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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. 119(e) of U.S. Provisional Patent Application No. 62/086,970, filed on Dec. 3, 2014 and entitled “Online Inspection for Composite Structures”, the contents of which are hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to the field of machine vision inspection and more particularly, to an online inspection/measurement system that is able to obtain measurements of features of a surface of a composite component in order to evaluate the acceptability of the features.
BACKGROUND OF THE ART
[0003] Composite structures (or components) are generally made from two or more constituent materials with significantly different physical or chemical properties. When combined, they produce a structure with characteristics different from the individual materials, with the aim of using the benefit of both.
[0004] When manufacturing composite structures using a manufacturing process such as Automated Fiber Placement (AFP) or Automated Tape Layering (ATL), inspecting the dimensional requirements of the manufactured structures is an important part of the manufacturing process. At least part of the inspection process is done on freshly laid fiber. It is very difficult to obtain high quality images from such surfaces due to the different directional reflectivity of the fibers. In addition, the features to be inspected are black details on black background, thus producing poor contrast.
[0005] For these reasons, known methods for performing dimensional inspection involve gathering data via manual inspection using a hand-held laser tracker, and having an operator compare the measured data with theoretical data from a Computer-Aided Design (CAD) file. In the case of a composite structure having many plies, manual inspection of the fibers of each ply of the structure is extremely time consuming. Another shortcoming of manual inspection is that it is dependent on the hand and eye skills of the operator, which makes it harder to validate the inspection at a later time.
[0006] There is therefore a need to improve the inspection phase of the manufacturing process for certain structures.
SUMMARY
[0007] There is described an online inspection method and system having an illumination system that provides bright-field and dark-field illumination concurrently or sequentially, at varying intensities, in order to acquire images that may be read by an image processing device. The image processing device may obtain measurements of features in the images and evaluate acceptability of the features.
[0008] In accordance with a first broad aspect, there is provided a system for online inspection of a composite structure manufactured by an automated tool. The system comprises an image acquisition device in proximity to a head of the tool above a surface of the composite structure and defining a field of view on the surface of the composite structure, the image acquisition device and the surface of the composite structure defining a bright-field illumination zone and a dark-field illumination zone; and an illumination system positioned above the surface of the composite structure. The illumination system comprises a top illumination light source inside the bright-field illumination zone, for projecting light at a first intensity onto the surface of the composite structure within the field of view that is reflected by the surface towards the image acquisition device; and a side illumination light source inside the dark-field illumination zone, for projecting light at a second intensity different from the first intensity onto the surface of the composite structure within the field of view that is reflected by the surface away from the image acquisition device.
[0009] In some embodiments, the system further comprises an optical adapter positioned between the image acquisition device and the surface of the composite structure for spacing the image acquisition device from the surface and/or directing a vision axis of the image acquisition device substantially perpendicularly to the surface. In some embodiments, an enclosure houses the optical adapter and the illumination system and is coupled to the image acquisition device.
[0010] In some embodiments, the image acquisition device comprises a lens having a long focal length F and a corresponding viewing distance D. In some embodiments, the long focal length F is at least five times longer than a diagonal of one of a film plane and a digital sensor of the image acquisition device. In some embodiments, the viewing distance D is at least twenty times longer than the diagonal of one of the film plane and the digital sensor of the image acquisition device.
[0011] In some embodiments, at least one of the top illumination light source and the side illumination light source comprises an array of Light Emitting Diodes (LEDs). In some embodiments, the array of LEDs is at least one of curved and composed of LEDs of varying intensities. In some embodiments, the LEDS comprise flash LEDs. In some embodiments, at least one of the top illumination light source and the side illumination light source comprises a backlighting plate.
[0012] In some embodiments, at least one of the top illumination light source and the side illumination light source projects colored light onto the surface. In some embodiments, the colored light is one of red-orange and blue.
[0013] In some embodiments, the image acquisition device comprises a shutter time synchronized with a response time of the illumination system.
[0014] In accordance with another broad aspect, there is provided a method for online inspection of a composite structure manufactured by an automated tool. The method comprises illuminating a surface of the composite structure by projecting light at a first intensity onto the surface of the composite structure from a top illumination light source and projecting light at a second intensity different from the first intensity onto the surface of the composite structure from a side illumination light source. The method also comprises acquiring an image of the illuminated surface of the composite structure using an image acquisition device in proximity to a head of the automated tool, the image acquisition device and the surface of the composite structure defining a bright-field illumination zone comprising the top illumination light source and a dark-field illumination zone comprising the side illumination light source.
[0015] In some embodiments, the method further comprises directing a vision axis of the image acquisition device substantially perpendicularly to the surface with an optical adapter. The optical adapter may also be used to space the image acquisition device from the surface. In some embodiments, the optical adapter and the illumination system are comprised in an enclosure coupled to the image acquisition device.
[0016] In some embodiments, acquiring an image comprises acquiring the image with a long focal length F and a corresponding viewing distance D. In some embodiments, the long focal length F is at least five times longer than a diagonal of one of a film plane and a digital sensor of the image acquisition device. In some embodiments, the viewing distance D is at least twenty times longer than the diagonal of one of the film plane and the digital sensor of the image acquisition device.
[0017] In some embodiments, at least one of the top illumination light source and the side illumination light source comprises an array of Light Emitting Diodes (LEDs). In some embodiments, the array of LEDs is at least one of curved and composed of LEDs of varying intensities. In some embodiments, the LEDS comprise flash LEDs. In some embodiments, at least one of the top illumination light source and the side illumination light source comprises a backlighting plate.
[0018] In some embodiments, illuminating the surface of the composite component comprises projecting colored light onto the surface. In some embodiments, the colored light is one of red-orange and blue.
[0019] In some embodiments, acquiring at least one image comprises acquiring a sequence of multiple images, each one with a different and customized illumination strategy applied in accordance with a specific local morphology of the surface of the composite structure.
[0020] In some embodiments, illuminating the surface of the composite structure comprises projecting light at the first intensity and projecting light at the second intensity in a sequential manner.
[0021] In this specification, a lens said to have a “long focal length” is intended to mean that it magnifies the image of the subject, such as a telephoto lens or a super telephoto lens. As the focal length of the lens increases, the depth of field gets shallower (for a same viewing distance) and the angle of view is narrower. As such, the term long focal length refers to the relationship between the absolute focal length of the lens and the diagonal of the film image. In some embodiments, the long focal length is provided from about 70 mm to about 300 mm. In some embodiments, the long focal length is provided from about 135 mm to about 300 mm. In some embodiments, the long focal length comprises a focal length greater than or equal to about 70 mm. In some embodiments, the long focal length is at least five times longer than the diagonal of a sensor provided in the image acquisition device. In some embodiments, a viewing distance for a long focal length is at least twenty times longer than the diagonal of the sensor provided in the image acquisition device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:
[0023] FIG. 1 is a schematic diagram of an exemplary system for online inspection of a composite structure manufactured by an automated tool;
[0024] FIG. 2 a is an exemplary image of the surface of a composite component captured while the surface is illuminated with only left side dark-field illumination;
[0025] FIG. 2 b is an exemplary image the surface of the composite component captured while the surface is illuminated with left side dark-field illumination and top side bright-field illumination;
[0026] FIG. 2 c is an exemplary image of the surface of the composite structure with a red-orange light illumination from the left side;
[0027] FIG. 2 d is an exemplary image of the surface of the composite structure with a red-orange light illumination from the top side;
[0028] FIG. 3 is an exemplary embodiment of a light guide used as an illumination source;
[0029] FIG. 4 is an exemplary embodiment of a system for online inspection having an optical adapter;
[0030] FIG. 5 a is an exemplary image of the surface of a composite component without any pre-processing;
[0031] FIG. 5 b is the image of FIG. 5 a with standard pre-processing;
[0032] FIG. 5 c is the image of FIG. 5 a with color inversion pre-processing; and
[0033] FIG. 6 is a flowchart of an exemplary method for the image acquisition phase of the online inspection of a composite structure manufactured by an automated tool.
[0034] It will be noted that throughout the appended drawings; like features are identified by like reference numerals.
DETAILED DESCRIPTION
[0035] A method and system for online inspection of a composite structure manufactured by an automated tool will be described. For illustrative purposes, the tool described is an Automated Fiber Placement (AFP) machine but other automated manufacturing tools, such as Automated Tape Layering (ATL) machines, may be used. In order to manufacture a composite structure using AFP, fiber strips (tows) are laid along a mold in multiple layers in order to create a composite structure having the shape of the mold. The fiber strips are placed along the mold in accordance with fiber laying trajectories that are input into the AFP machine to create a given structure in accordance with a set of design parameters. Some of the features that may be inspected include, but are not limited to, fiber gaps, fiber overlap, angle deviations, debris, and tow positions.
[0036] The composite structure may comprise various materials, such as but not limited to cements, concrete, reinforced plastics, metal composites and ceramic composites. For example, the composite structure may be composed of composite fiber-reinforced plastics. The composite structure may be used for various applications, including but not limited to buildings, bridges, space crafts, aircrafts, watercrafts, land vehicles including railway vehicles, and structures such as wind turbine blades, swimming pool panels, bathtubs, storage tanks, and counter tops.
[0037] The system for online inspection of a composite structure manufactured by an automated tool generally comprises an image acquisition device 100 and an illumination system 101 , as illustrated in FIG. 1 . The image acquisition device 100 may be any instrument that records images that can be stored directly, transmitted to another location, or both. For example, the image acquisition device 100 may be a video camera, a still camera, a digital camera, an image sensor, a CCD sensor, a CMOS sensor, and an active pixel sensor, among other possibilities.
[0038] Images are processed by an image processor (not shown) to perform inspection in real time or substantially real time, i.e. as each layer is being laid upon the mold to form the composite structure. The image acquisition device 100 is mounted to a head of the automated tool 103 and defines a field of view (FOV) on a surface of the composite structure 106 . Also defined by the image acquisition device 100 and the surface of the composite structure 106 are a bright-field illumination zone 105 and a dark-field illumination zone 107 . The bright-field illumination zone 105 is the area above the composite structure surface 106 where light emitted from a light source and projected within the FOV will be reflected into the image acquisition device 100 . The dark-field illumination zone 107 is the area above the composite structure surface 106 where light emitted from a light source and projected within the FOV will be reflected away from the image acquisition device 100 . One or more top illumination light sources 102 is provided inside the bright-field illumination zone 105 . One or more side illumination light source 104 is provided inside the dark-field illumination zone 107 . In some embodiments, four side illumination lights sources 104 are provided, namely a front side source, a back side source, a left side source, and a right side source.
[0039] The illumination system 101 is thus a combination of dark-field light and bright-field light and is provided in order to reveal sufficient details available on the surface 106 of the composite structure to ensure that an image captured by the image acquisition device 100 may contain enough information to be successfully processed by an image processor. The side illumination light source 104 is provided at a first intensity and is used to create high contrast images from shadows, i.e. highlight the surface details. However, too much shadow prevents accurate measurement from the image processor. While a human operator may be able to distinguish more easily the defects in a high contrast image, excess shadow may be problematic for an image processor. The top illumination light source 102 is thus provided at a second intensity different from the first intensity to fill the edges of the shadows created by the side illumination light source 104 so that these edges are not mistaken by the image processor as real features.
[0040] FIGS. 2 a and 2 b illustrate the difference between having only dark-field illumination and having a combination of bright-field and dark-field illumination. FIG. 2 a shows an image of a surface illuminated only with a left side illumination light source 104 and no top illumination light. FIG. 2 b shows an image of the same surface illuminated with a left side illumination light source 104 and a top illumination light source 102 . Using the right proportion of dark field and bright field illumination, the shadow edges seen in FIG. 2 a are reduced or substantially eliminated while preserving the high contrast of the image. The illumination system 101 is thus conceived specifically for an online system whereby images are processed in real-time and automatically.
[0041] The illumination system 101 may comprise a diffuser in order to create non-coherent light and thus avoid noise introduced by sparkling reflections over the fiber details (speckles) and strong casted shadows. The diffuser may be provided for the top illumination light source 102 and/or the side illumination light source 104 . In order to increase the depth of field; the image acquisition device 100 may be provided with an aperture that closes a large portion of the optical field of the lens. A fast shutter speed (with a short opening time) may be used to ensure a short exposure time, so that the image is not blurred, as images are taken while the surface is moving. A light source with a very fast response time may be used to allow precise synchronization with the shutter speed of the image acquisition device 100 . In addition, the settings for the image acquisition device 100 , such as the shutter speed and the aperture size; may be different from image to image and may change in real time. The automatic adjustment of settings allows the quality of the images captured by the image acquisition device to be consistent while capturing images of different surface particularities, such that they may be inspected in an automated mode in real time while the surface is moving.
[0042] In some embodiments, the top illumination source 102 and/or the side illumination source 104 comprises a light guide 300 as illustrated in FIG. 3 . The light guide 300 may be composed of a prism and multiple mirrors. An LED (Light Emitting Diode) light source 302 is provided on at least one side edge of the light guide 300 . A primary scattering mirror 304 is providing along a top edge of the light guide 300 while a secondary scattering mirror 306 is provided along a bottom edge thereof. The light guide can be a prism as illustrated or a long bundle made of fiber optics. An exit scattering window 308 allows scattered (i.e. very diffuse light) light to exit from the bottom edge of the light guide 300 . Alternatively or in combination with the light guide 300 , the top illumination source 102 and/or the side illumination source 104 comprises an LED array illumination plate. The plate may be straight or curved to widen the field of view. The LEDs in the array may also be modulated in intensity in order to provide an even illumination field. In other words, each LED in the array may have its intensity set independently to obtain the desired illumination field. Alternatively or in combination with the light guide 300 , and/or the LED array illumination plate, the top illumination source 102 and/or the side illumination source 104 comprises a liquid crystal display (LCD) back illumination system, referred to herein as a backlighting plate. A backlighting plate may thus provide a very even illumination field with a high level of diffusibility, and include the side illumination source 104 and the light guide in one compact feature. The backlighting plate may also be curved and/or have individual nano-imprinted micro lenses regulated to a desired intensity level.
[0043] In some embodiments, the intensity of the light sources (side and/or top) may be too high to provide continuous illumination as this may cause the surface 106 to burn or be cured. Flash LED illumination may be used. Such light sources have a very short response time and also emit “cold” light. The flash LED illumination intensity is usually at least one order of magnitude higher than of a continuous mode LED illumination, for the short time provided by the shutter, thus allowing for a brighter or more intense illumination system 101 . In addition, the small dimension of flash LEDs allows installation in a dense array, thereby achieving very even light emissivity from the light source.
[0044] In some embodiments, the top illumination source 102 and/or the side illumination source 104 may be configured to project colored light onto the surface 106 . Colors may be used to distinguish between layers of the composite structure. For example, when illuminating the surface 106 with a light frequency in the red-orange portion of the visible light spectrum, light absorption is very high and strongly dependent on fiber orientation. Different plies of the structure may thus be revealed using red-orange light using fiber orientation. The last ply of the ply lay-up may be visually “detached” from the previous ply using red-orange light. FIGS. 2 c and 2 d are exemplary embodiments of the composite structure imaged with a red-orange light. In FIG. 2 c , the red-orange light is provided only from the side illumination source 104 while in FIG. 2 d , the red-orange illumination is provided only from the top illumination source 102 . As shown, in both cases, the last ply is clearly distinguished from the previous ply.
[0045] The red-orange light may be provided at a wavelength of about 625 nm to about 775 nm. In some embodiments, orange light at a wavelength of about 590 nm may be used. In some embodiments, red light at a wavelength of about 650 nm may be used. In some embodiments, red-orange light at a wavelength of about 621 nm may be used. In another example, blue light can be used to create high contrast images due to the high reflectivity of the AFP surface. Blue light may be provided at a wavelength of about 425 nm to about 490 nm. In some embodiments, blue light may be provided at a wavelength of about 475 nm. Other colors may also be used, as a function of a desired reflectivity and/or absorption of the light on the material. Color may be chosen based on the material of the composite structure, and/or the color of the material, and/or based on the desired purpose of the lighting and image acquisition, i.e. to distinguish between plies or to highlight certain details on the surface of the structure. Colored light may be used in combination with white light in order to create a desired effect.
[0046] In some embodiments, the top illumination source 102 and/or the side illumination source 104 may be configured to project infrared light onto the surface 106 . When the surface is pre-heated by a heat lamp to improve tackiness, the last ply of carbon is hot from the compaction roller. A camera can be set to acquire images in the infrared domain in order to distinguish the hot layer from the background, similarly to the embodiment with red-orange illumination.
[0047] As shown in FIG. 1 , the surface 106 of the composite structure may be curved, thus introducing parallax errors into the images. Parallax errors may be minimized by having a small field of vision, a vision direction that is perpendicular to the surface, a small angle of vision (or long vision distance), and/or inspection performed very close to the surface. When imaging the surface of a composite structure manufactured by AFP, the vision field cannot be reduced beyond a certain size imposed by the ply lay-up geometry. The free space close to the compaction roller is limited, thus complicating installation of the camera near the surface of the composite structure and with the vision direction perpendicular to the surface. In addition, a long vision distance also makes installing the camera in proximity to the compaction roller a challenge. As a result, in some embodiments, the online inspection system is provided with an optical adapter positioned between the image acquisition device and the surface of the composite structure for spacing the image acquisition device from the surface and directing a vision axis of the image acquisition device substantially perpendicularly to the surface. The image acquisition device may thus be mounted to the head of the tool and a long focal length is used for the image acquisition device.
[0048] FIG. 4 is a side view of an exemplary embodiment of an online inspection system 400 having a long focal length and an optical adapter. A camera 408 provided with a lens having a long focal length is mounted to the AFP lay-up head 402 . The optical adapter 412 spaces the camera 408 from the surface 406 and directs a vision axis of the camera 408 substantially perpendicularly to the surface 406 . The spacing of the camera 408 from the surface 406 also allows room for the illumination system 410 below the camera 408 and above the surface 406 . The illumination system 410 and the optical adapter 412 may be provided in a single housing 409 . In some embodiments, the housing may be a darkroom enclosure, in order to block out all ambient light and allow for better control of light projected onto the surface 406 of the composite structure. Alternatively, the housing 309 may enclose only the illumination system 410 , and the optical adapter 412 may be provided separately therefrom.
[0049] The optical adapter 412 may be composed of one or more optical elements for directing the vision axis of the image acquisition device perpendicularly to the surface being imaged. For example, the optical adapter 412 may be composed of a half-penta prism or a pair of mirrors. Other optical elements may also be used.
[0050] In some embodiments, the online inspection system 400 is provided with a long vision distance, a short shutter time, a closed aperture, high intensity illumination, very diffuse illumination, no light coherency or very low light coherency of the light beam, a shallow angle illumination very close to the surface, a top side illumination in conjunction with a shallow angle illumination, a flash illumination light source having a very fast response, and light emitted at a specific wavelength to detach the last ply from the background. While it may seem that diffuse light sources are readily available, the level of diffusibility required by the composite surface is much higher than what is currently available. This is due to the very small dimension of the fibers, which can easily create speckle if the illumination light is even only a little bit coherent.
[0051] In some embodiments, color inversion is used to enhance a contrast between the dark features of the composite structure and the dark background. Color inversion facilitates filtering of the background of the image after feature extraction without losing useful information. Color inversion may be particularly useful when the features themselves are black and the background is black, thus having very low contrast. FIG. 5 a is an example of an original image as captured by an image acquisition device of an online inspection system. In this example, the objective is to detect gaps in the surface of the composite structure. FIG. 5 b is an example of the original image after standard preprocessing typically applied to the image. As shown, many features can be seen on the image, not only the gaps. FIG. 5 c is an example of the original image with color inversion. The gaps 502 are clearly shown without additional features in the image. The level of filtering may be automated since the feature to background ratio can be optimized in a feedback loop of the processor.
[0052] FIG. 6 is a flowchart of an exemplary embodiment of a method for online inspection of a composite structure manufactured by an automated tool. The method comprises a first step 600 of illuminating the surface of the composite structure followed by a step 606 of acquiring at least one image of the illuminated surface. The illumination step 600 may be composed of a step 602 of projecting bright-field illumination onto the surface of the composite component and a step 604 of projecting dark-field illumination onto the surface of the composite component. The bright-field illumination is provided by a top illumination light source at a first intensity and the dark-field illumination is provided by a side illumination light source at a second intensity different from the first intensity. The two intensities are adjusted to provide a suitably contrasted image without too much shadow, in order to allow an image processor to detect features in the image and/or perform measurements in the image. The bright field illumination and the dark field illumination steps can be applied simultaneously or in sequence one after the other (but in the same shutter opening). The sequence application may be used if different colors are used for dark field and bright field illumination, to avoid unpredictable subtractive or additive color formation.
[0053] In some embodiments, acquiring at least one image comprises acquiring a sequence of multiple images. Each one of the images in the sequence may be acquired with a different and customized illumination strategy. The illumination strategy may be selected/applied in accordance with a specific local morphology of the surface of the composite structure. The method may thus be adapted in real time to the surface of the composite component, and inspection may be performed in an automated manner.
[0054] As stated above, the image acquisition device may be mounted to the head of the automated tool. Alternatively, the image acquisition device may be built into the head of the tool. The image processor may be provided remotely from the image acquisition device, thus allowing the portion of the system attached to the head of the automated tool to remain lightweight and small in volume. Color inversion image preprocessing may be used for the detection of certain types of features. Color inversion may be applied directly by the image processor or by an intermediate device receiving the acquired image from the image acquisition device, such as a Programmable Logic Controller (PLC), an upper level controller, etc.
[0055] The methods and systems described herein allow for real-time inspection of freshly laid fiber in a timely manner. The high volume of features and locations on the composite structure requires speed so as to account for changes in surface reflectivity as the surface of the composite structure dries. The means described herein used to enhance the contrast of the features under inspection, such as light frequencies, illumination type, and angles of illumination, allow high quality images to be acquired for a quick and automated inspection process.
[0056] The above description is meant to be exemplary only, and one skilled in the relevant arts will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. For example, the blocks and/or operations in the flowcharts and drawings described herein are for purposes of example only. There may be many variations to these blocks and/or operations without departing from the teachings of the present disclosure. For instance, the blocks may be performed in a differing order, or blocks may be added, deleted, or modified. The structure illustrated is thus provided for efficiency of teaching the present embodiment. The present disclosure may be embodied in other specific forms without departing from the subject matter of the claims. Also, one skilled in the relevant arts will appreciate that while the systems and methods disclosed and shown herein may comprise a specific number of elements/components, the systems and methods may be modified to include additional or fewer of such elements/components. The present disclosure is also intended to cover and embrace all suitable changes in technology. Modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.
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There is described an online inspection method and system having an illumination system that provides bright-field and dark-field illumination concurrently or sequentially, at varying intensities, in order to acquire images that may be read by an image processing device. The image processing device may obtain measurements of features in the images and evaluate acceptability of the features.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a lens drive control device and an image pickup apparatus using the lens drive control device and, more particularly, to a lens drive control device and an image pickup apparatus suited for use in small-sized electronic still cameras (e.g., digital cameras) having an image pickup element such as a CCD (charge-coupled device).
[0003] 2. Description of Related Art
[0004] In recent years, the image pickup apparatus using an image pickup element such as a CCD have been widespread in the form of video cameras or electronic still cameras. These image pickup apparatus are capable of taking and storing a video image with ease. The stored video image can be viewed on the CRT (cathode-ray tube) or like display device or printed out as photographs.
[0005] However, the conventional video camera and electronic still camera trend to take over the system of the silver-halide film camera without any considerable alternation. For the electronic still camera, some disadvantages arise in employing all the features of that system.
[0006] For example, lens drive systems which prevail in the lens-shutter-type silver-halide cameras have a common feature that, when switched from the non-shooting mode where the lens barrel is retracted into the camera body to the shooting mode, the zoom lens is driven to the wide-angle end in response to turning-on of the electric power supply. On the contrary, for the small-sized electronic still camera, there are occasions that such an initial setting is unfavorable.
[0007] An appropriate type of optical system to the small-sized electronic still camera is the negative lead type of zoom lens in which the front lens unit is negative in refractive power and the rear lens unit is positive in refractive power. In some cases, the physical length for the wide-angle end of the negative lead type of zoom lens becomes longer than for the telephoto end. With the zoom lens of such a form, when the electric power supply is turned on, it results that the initial setting process of the zoom lens goes to the wide-angle end after having once passed across the telephoto end. On the contrary, the electronic still camera has a feature that the telephoto end is rather more often enjoyed than the wide-angle end. This is because, when the electronic still camera is used as a document camera to read documents into the computer or to shoot personal name cards, the telephoto end is usually used at which the distortion is lesser than at the wide-angle end.
[0008] On consideration of such a usage of the electronic still camera, it is not always necessary to take the initial setting in the wide-angle end in response to turning-on of the power supply. Also, in the lens configuration described above, the initial setting process overruns the telephoto end which is rather high in the frequency of use. Therefore, the zoom lens is apt to be driven wastefully, thereby causing the premature consumption of the battery.
BRIEF SUMMARY OF THE INVENTION
[0009] An object of the present invention is to provide a lens drive control device which prevents the lens from being driven wastefully when the electric power supply is turned on, and an image pickup apparatus using the lens drive control device.
[0010] To attain the above object, in accordance with an aspect of the invention, there is provided a lens drive control device, which comprises a zoom lens, drive means for driving at least one lens unit which constitutes the zoom lens, control means for controlling the drive means, and a switch for switching between a shooting state and a non-shooting state of the zoom lens, wherein, when the zoom lens is switched from the non-shooting state to the shooting state by the switch, the control means causes the drive means to drive the zoom lens to a zoom position other than a wide-angle end.
[0011] In accordance with another aspect of the invention, there is provided a lens drive control device, which comprises a zoom lens in which a distance between a lens surface closest to an object side and a lens surface closest to an image side becomes minimum in a predetermined zoom position other than a wide-angle end, drive means for driving at least one lens unit which constitutes the zoom lens, control means for controlling the drive means, and a switch for switching between a shooting state and a non-shooting state of the zoom lens, wherein, when the zoom lens is switched from the non-shooting state to the shooting state by the switch, the control means causes the drive means to drive the zoom lens to the predetermined zoom position.
[0012] In accordance with a further aspect of the invention, there is provided a lens drive control device, which comprises a zoom lens, drive means for driving at least one lens unit which constitutes the zoom lens, control means for controlling the drive means, a switch for switching between a shooting state and a non-shooting state of the zoom lens, storage means for storing a zoom position taken when the zoom lens has been switched from the shooting state to the non-shooting state by the switch, and command means for issuing a command to read out the zoom position stored in the storage means, wherein, when the zoom lens is switched from the non-shooting state to the shooting state by the switch, if the command to read out the zoom position stored in the storage means is issued by the command means, the control means causes the drive means to drive the zoom lens to the zoom position stored in the storage means.
[0013] In accordance with a still further aspect of the invention, there is provided an image pickup apparatus having the lens drive control device described above.
[0014] These and further aspects and features of the invention will become apparent from the following description of preferred embodiments thereof taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0015] [0015]FIG. 1 is a block diagram of an image pickup apparatus having a lens drive control device according to an embodiment of the invention.
[0016] [0016]FIG. 2 is a flow chart for explaining an operation of the image pickup apparatus.
[0017] [0017]FIG. 3 is a flow chart for explaining the operation of the image pickup apparatus.
[0018] [0018]FIG. 4 is a sectional side view of a lens part of the image pickup apparatus.
[0019] [0019]FIG. 5 is a front view of the lens part of the image pickup apparatus.
[0020] [0020]FIG. 6 is a diagram showing the zooming movements of lens units of a numerical example 1 of an optical system in the embodiment of the invention.
[0021] FIGS. 7 (A), 7 (B) and 7 (C) are longitudinal section views of the numerical example 1 of the optical system in three operative positions.
[0022] FIGS. 8 ( 1 ), 8 ( 2 ), 8 ( 3 ) and 8 ( 4 ) are graphic representations of the aberrations of the numerical example 1 of the optical system in the wide-angle end.
[0023] FIGS. 9 ( 1 ), 9 ( 2 ), 9 ( 3 ) and 9 ( 4 ) are graphic representations of the aberrations of the numerical example 1 of the optical system in a middle focal length position.
[0024] FIGS. 10 ( 1 ), 10 ( 2 ), 10 ( 3 ) and 10 ( 4 ) are graphic representations of the aberrations of the numerical example 1 of the optical system in the telephoto end.
[0025] [0025]FIG. 11 is a diagram showing the zooming movements of lens units of a numerical example 2 of an optical system in the embodiment of the invention.
[0026] FIGS. 12 (A), 12 (B) and 12 (C) are longitudinal section views of the numerical example 2 of the optical system in three operative positions.
[0027] FIGS. 13 ( 1 ), 13 ( 2 ), 13 ( 3 ) and 13 ( 4 ) are graphic representations of the aberrations of the numerical example 2 of the optical system in the wide-angle end.
[0028] FIGS. 14 ( 1 ), 14 ( 2 ), 14 ( 3 ) and 14 ( 4 ) are graphic representations of the aberrations of the numerical example 2 of the optical system in a middle focal length position.
[0029] FIGS. 15 ( 1 ), 15 ( 2 ), 15 ( 3 ) and 15 ( 4 ) are graphic representations of the aberrations of the numerical example 2 of the optical system in the telephoto end.
[0030] [0030]FIG. 16 is a diagram showing the zooming movements of lens units of a numerical example 3 of an optical system in the embodiment of the invention.
[0031] FIGS. 17 (A), 17 (B) and 17 (C) are longitudinal section views of the numerical example 3 of the optical system in three operative positions.
[0032] FIGS. 18 ( 1 ), 18 ( 2 ), 18 ( 3 ) and 18 ( 4 ) are graphic representations of the aberrations of the numerical example 3 of the optical system in the wide-angle end.
[0033] FIGS. 19 ( 1 ), 19 ( 2 ), 19 ( 3 ) and 19 ( 4 ) are graphic representations of the aberrations of the numerical example 3 of the optical system in a middle focal length position.
[0034] FIGS. 20 ( 1 ), 20 ( 2 ), 20 ( 3 ) and 20 ( 4 ) are graphic representations of the aberrations of the numerical example 3 of the optical system in the telephoto end.
DETAILED DESCRIPTION OF THE INVENTION
[0035] Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.
[0036] [0036]FIG. 1 is a block diagram showing an image pickup apparatus having a lens drive control device according to an embodiment of the invention.
[0037] Referring to FIG. 1, a first lens unit 1 has a negative refractive power. A second lens unit 2 has a positive refractive power. The first lens unit 1 acts as the compensator, while the second lens unit 2 acts as the variator. The first and second lens units 1 and 2 constitute a zoom lens. Incidentally, for the zoom lens configuration, many other types may be considered. So, it is to be understood that the zoom lens in the invention is not confined to the type shown in FIG. 1.
[0038] A stop SP, an optical low-pass filter 3 and an image sensor 4 such as interline-type CCD are included in the optical system. Light entering through the first lens unit 1 is adjusted in the intensity by the stop SP and passes through the second lens unit 2 and the low-pass filter 3 to form an image on the image sensor 4 .
[0039] An amplifier 5 amplifies an output signal of the image sensor 4 and outputs the amplified output signal. A camera processing circuit 6 processes the output signal of the amplifier 5 as a video signal. The video signal outputted from the camera processing circuit 6 is supplied to a recording part 7 , where the video signal is recorded on a recording medium. As the recording medium, a magnetic disc, a magnetic tape, a PC card, or a magneto-optical disc may be considered.
[0040] An electric motor 8 drives the stop SP, and is controlled by a CPU 14 . An auto-focus (AF) circuit 9 determines a focusing state of the zoom lens at the present time on the basis of the video signal from the camera processing circuit 6 and outputs information on the focusing state to the CPU 14 . In the image pickup apparatus in the present embodiment, the AF method to be used is assumed to take it as the in-focus position when a frequency component of the luminance component of the video signal reaches a peak, or the so-called the “TV signal” AF. Instead of this, the TCL type, or the infrared type may be used.
[0041] A focusing lens is driven to axially move in such a way as to make minute excursions on the basis of the information on the focusing state sent from the AF circuit 9 . In the case of the embodiment, the focusing lens may be either the first lens unit 1 or the second lens unit 2 . Otherwise, both of the lens units 1 and 2 may be used as the focusing lens. As the focusing lens is driven to minutely oscillate, the luminance signal of video signal obtained by the image sensor 4 oscillates in synchronism with the oscillation of the focusing lens. Such a luminance signal is transferred from the image sensor 4 through the camera processing circuit 6 and the AF circuit 9 to the CPU 14 . When the luminance signal exceeds a certain value, the CPU 14 determines that an in-focus state has been attained and, then, stops the focusing lens from further excursion.
[0042] A reset switch 10 is provided for the first lens unit 1 . When a counter disposed in the CPU 14 is used to measure the moving amount of the first lens unit 1 , the reset switch 10 functions as a sensor for the reference position. Another reset switch 11 is provided for the second lens unit 2 . When another counter disposed in the CPU 14 is used to measure the moving amount of the second lens unit 2 , the reset switch 11 functions as a sensor for the reference position.
[0043] Stepping motors 12 and 13 function as drive means for moving the lens units 1 and 2 , respectively. When the lens units 1 and 2 are moved to effect zooming, focusing, or retracting, the stepping motors 12 and 13 are energized through respective drivers 20 and 21 .
[0044] The CPU 14 functions as a control means, and, in response to the respective input signals, controls the movements of the motor 8 for the stop SP, the stepping motors 12 and 13 , an electronic shutter, and others. A trigger switch 15 , when pushed, renders the CPU 14 to actuate the electronic shutter and the recording part 7 so that the video image formed on the image sensor 4 is taken in and recorded on the recording medium. A memory 16 temporarily stores information on the zoom position taken when the electric power supply is turned off.
[0045] A power supply switch 17 , when closed, connects the electric power supply to the CPU 14 . A zoom switch 18 , when pushed to the wide-angle end, actuates the CPU 14 to command the drivers 20 and 21 so that zooming goes to the wide-angle end, or when pushed to the telephoto side, zooming goes to the telephoto side, or when not pushed, zooming does not take place.
[0046] A recovery switch 19 determines which zoom position is resumed as the zoom lens moves when the power supply switch 17 is turned on again, depending on its ON/OFF position. In the present embodiment, if the recovery switch 19 is in the ON position, setting is carried out so that the zoom lens is driven to the position stored in the memory 16 obtained when the power supply has been last turned off. If the recovery switch 19 is in the OFF position, the zoom lens is driven to a position where the overall lens length (distance from a lens surface closest to the object side to a lens surface closest to the image side) of the zoom lens becomes shortest.
[0047] Next, an operation of the image pickup apparatus according to the embodiment is described with reference to flow charts shown in FIGS. 2 and 3.
[0048] After the flow of operation has started at a step F 10 , the ON/OFF of the power supply switch 17 is first determined. If the power supply switch 17 is in the on-state, the flow proceeds to a step F 12 , where the ON/OFF of the recovery switch 19 is determined.
[0049] If the recovery switch 19 is in the off-state, the flow proceeds to a step F 13 , where the lens units 1 and 2 are driven from the retracted position (stowage position) to the zoom positions where the overall lens length becomes shortest. Meanwhile, if the recovery switch 19 is in the on-state, the memory 19 is accessed at a step F 14 to read out the zoom position stored. Then, at a step F 15 , the lens units 1 and 2 are driven to the read-out zoom position.
[0050] If the zoom switch 18 is found to be turned on (to either one of the wide-angle and telephoto sides) at a step F 16 , the flow proceeds to a step F 17 , where the lens units 1 and 2 are driven along their respective loci toward the wide-angle end or the telephoto end depending on the switched side of the zoom switch 18 . If the zoom switch 18 is found to be turned off, the flow proceeds to a step F 18 , skipping the step F 17 .
[0051] If, at the step F 18 , the trigger switch 15 is found to be turned on, the flow proceeds to a step F 19 , where the AF circuit 9 is driven to effect automatic focusing. If, at a step F 20 , an in-focus state is found to be attained, the flow proceeds to a step F 21 , where the video image is taken in. At the next step F 22 , the recording part 17 carries out recording of the video image on the recording medium. If the trigger switch 15 is found to be turned off, the flow returns to the step F 16 .
[0052] A step F 23 , a check is made to find the ON/OFF of the power supply switch 17 . If the power supply switch 17 is found to be turned on, the flow returns to the step F 16 . If the power supply switch 17 is found to be turned off, the flow proceeds to a step F 24 , where the current zoom position is stored in the memory 16 . At the next step F 25 , the lens units 1 and 2 are driven to the position where the overall lens length becomes shortest. Then, at a step F 26 , the zoom lens is stowed (retracted) into the camera body. Then, the power supply is turned off at a step F 27 .
[0053] Next, with reference to FIGS. 4 and 5, the structural arrangement of a lens part of the image pickup apparatus in the present embodiment is described below. FIG. 4 is a longitudinal side section view of the lens part and FIG. 4 is a front end view of the same.
[0054] In FIGS. 4 and 5, an axially movable first lens unit 101 , an axially movable diaphragm unit 102 and an axially movable second lens unit 103 correspond to the first lens unit 1 , the stop SP and the second lens unit 2 , respectively, shown in FIG. 1. A holding frame 104 holds the first lens unit 101 . As the holding frame 104 moves axially, the holding frame 104 is restrained from rotation by a guide bar 105 . The guide bar 105 has such a stroke as to cause the overall lens length of the zoom lens to become shorter in the non-shooting state than in the shooting state. Another guide bar 106 guides the diaphragm unit 102 to move along the optical axis, and has such a stroke as to cause the overall lens length of the zoom lens to become shorter in the non-shooting state than in the shooting state. A holding frame 107 holds the second lens unit 103 . As the holding frame 107 moves axially, the holding frame 107 is restrained from rotation by a guide bar 108 . The guide bar 105 has such a stroke as to cause the overall lens length of the zoom lens to become shorter in the non-shooting state than in the shooting state. A U bar 109 restrains the first holding frame 104 , the diaphragm unit 102 and the second holding frame 107 from turning about the respective guide bars 105 , 106 and 108 in the direction perpendicular to the optical axis, and has such a stroke as to cause the overall lens length of the zoom lens to become shorter in the non-shooting state than in the shooting state.
[0055] A stepping motor 110 is arranged to drive the holding frame 104 axially. A rack 111 transmits the driving force of the stepping motor 110 to the holding frame 104 . A sensor 112 is arranged to detect the initial position of the first lens unit 101 . Another stepping motor 113 is arranged to drive the second lens unit 103 axially. Another rack 114 transmits the driving force of the stepping motor 113 to the holding frame 107 . Another sensor 115 is arranged to detect the initial position of the second lens unit 103 . The stepping motors 110 and 113 correspond to the stepping motors 12 and 13 shown in FIG. 1, respectively, and the sensors 112 and 115 correspond to the reset switches 10 and 11 shown in FIG. 1, respectively.
[0056] A spring 116 urges the diaphragm unit 102 always toward the object side. A main tube 117 holds the guide bars 105 , 106 and 108 and the bar 109 at their one ends, and fixedly carries the stepping motors 110 and 113 and the sensors 112 and 115 .
[0057] A CCD unit 118 is integrally composed of a low-pass filter 118 a and a chip 118 c and has an image receiving surface 118 b . The CCD unit 118 corresponds to a combination of the low-pass filter 3 and the image sensor 4 shown in FIG. 1.
[0058] A rear tube 119 holds the guide bars 105 , 106 and 108 and the U bar 109 at their opposite ends and fixedly carries the CCD unit 118 . The stepping motors 110 and 113 are mounted on a motor holding plate 120 .
[0059] The upper half of FIG. 4 shows the state of the lens part in which the first lens unit 101 is in the most forward position. The lower half of FIG. 4 shows the state in which the lens part is in the retracted position. In moving the first lens unit 101 forward, the stepping motor 110 is energized to transmit its driving force to the rack 111 . The driving force transmitted to the rack 111 causes the holding frame 104 to axially move forward. Along with the forward movement of the holding frame 111 , the diaphragm unit 102 which is urged by the spring 116 toward the object side, too, is moved forward. The diaphragm unit 102 , which is being moved forward, eventually abuts on a stopper 117 a provided on the main tube 117 and stops from further moving forward, thus reaching the position of the upper half of FIG. 4. On the other hand, in moving the first lens unit 101 backward, the stepping motor 110 is energized in the reversed direction. So, the reverse driving force of the stepping motor 110 is transmitted to the rack 111 to move the holding frame 104 toward the image side. After a projection 104 a of the holding frame 104 , which is being moved backward, abuts on the diaphragm unit 102 , the diaphragm unit 102 , too, is moved backward together with the holding frame 104 , thus reaching the position of the lower half of FIG. 4.
[0060] The driving force generated by the stepping motor 113 is transmitted through the rack 114 to the holding frame 107 , thus axially moving the holding frame 107 backward and forward. The sensor 112 is arranged to detect the initial position of the holding frame 104 and the sensor 115 is arranged to detect the initial position of the holding frame 107 . The sensors 112 and 115 send detection signals to a CPU (not shown in FIGS. 4 and 5), which corresponds to the CPU 14 shown in FIG. 1. The CPU controls the energization of the stepping motors 110 and 113 in accordance with the detection signals received.
[0061] Next, numerical examples 1 to 3 of optical systems suited for use in the lens drive control device in the present embodiment are shown. In the numerical data for the examples 1 to 3, ri is the radius of curvature of the i-th lens surface, when counted from the object side, di is the i-th lens thickness or air separation, when counted from the object side, ni is the refractive index of the material of the i-th lens element, when counted from the object side, and υi is the Abbe number of the material of the i-th lens element, when counted from the object side. The lens surface indicated by * is an aspheric surface, and in the numerical data there are also the values of the radius of the osculating sphere and the aspheric coefficients in the following polynomial:
X = h 2 / R 1 + 1 - ( 1 + K ) ( h / R ) 2 + Bh 2 + Ch 6 + Dh 8
[0062] where X is the coordinate in the direction of the optical axis and h is the coordinate in the direction perpendicular to the optical axis, the direction in which light advances being taken as positive. R is the radius of the osculating sphere, and K, B, C and D are the aspheric coefficients. Also, the notation D-0X means 10 −x .
Numerical Example 1: f = 3.74849 Fno = 1:2.8 2ω = 64.8° r1 = 205.814 d1 = 1.00 n1 = 1.74330 ν1 = 49.2 *r2 = 3.621 d2 = 1.35 r3 = 6.370 d3 = 2.10 n2 = 1.64769 ν2 = 33.8 r4 = 46.696 d4 = Variable r5 = ∞(Stop) d5 = Variable r6 = 4.880 d6 = 2.20 n3 = 1.83400 ν3 = 37.2 r7 = −76.972 d7 = 0.18 r8 =−20.357 d8 = 1.60 n4 = 1.84666 ν4 = 23.8 r9 = 3.588 d9 = 0.11 r10 = 3.929 d10 = 1.90 n5 = 1.73077 ν5 = 40.6 *r11 = −84.003 d11 = Variable r12 = ∞ d12 = 3.10 n6 = 1.51633 ν6 = 64.2 r13 = ∞ Variable Focal Length Separation 3.75 8.55 11.02 d4 11.74 2.17 1.20 d5 6.69 2.61 1.20 d11 2.00 5.62 7.49 Aspheric Coefficients: For r2: R = 3.62053D + 00 K = −1.06318D + 00 B = 1.10799D − 03 C = −3.27073D − 06 For r11: R = 8.40029D + 01 K = −2.06156D + 02 B = 2.51718D − 03 C = 1.50000D − 04 Numerical Example 2: f = 3.75003 Fno = 1:2.8 2ω =63.6° r1 = 60.170 d1 = 1.00 n1 = 1.74330 ν1 = 49.2 *r2 = 3.472 d2 = 2.78 r3 = 8.363 d3 = 4.13 n2 = 1.84666 ν2 = 23.8 r4 = 17.062 d4 = Variable r5 = ∞(Stop) d5 = 1.10 r6 = 6.211 d6 = 4.78 n3 = 1.69680 ν3 = 55.5 r7 = −10.395 d7 = 0.31 r8 = −6.817 d8 = 2.00 n4 = 1.84666 ν4 = 23.8 r9 = −2163.195 d9 = 1.20 r10 = 10.043 d10 = 1.60 n5 = 1.73077 ν5 = 40.6 *r11 = 21.256 d11 = Variable r12 = 154.453 d12 = 1.00 n6 = 1.80400 ν6 = 46.6 r13 = −23.948 d13 = 3.10 r14 = ∞ d14 = 3.10 n7 = 1.51633 ν7 = 64.2 r15 = ∞ Variable Focal Length Separation 3.75 8.60 11.10 d4 11.85 2.69 1.10 d11 1.12 9.04 13.12 Aspheric Coefficients: For r2: R = 3.47155D + 00 K = −1.52122D + 00 B = 2.11152D − 03 C = −1.34125D − 05 For r11: R = 2.12556D + 01 K = 6.49763D + 01 B = 3.59566D − 04 C = −5.36520D − 05 Numerical Example 3: f = 3.75000 Fno = 1:2.8 2ω = 64.6° r1 = −1580.189 d1 = 1.00 n1 = 1.58313 ν1 = 59.4 *r2 = 2.786 d2 = 1.85 r3 = 5.844 d3 = 1.50 n2 = 1.84666 v2 = 23.8 r4 = 10.648 d4 = Variable r5 = ∞(Stop) d5 = 1.10 r6 = 5.328 d6 = 2.10 n3 = 1.58313 ν3 = 59.4 r7 = −11.129 d7 = 0.30 r8 = −44.181 d8 = 1.00 n4 = 1.84666 ν4 = 23.8 r9 = 6.765 d9 = 0.38 *r10 = −17.497 d10 = 1.50 n5 = 1.80610 ν5 = 40.9 r11 = −6.978 d11 = Variable r12 = 12.184 d12 = 1.50 n6 = 1.51633 ν6 = 64.1 r13 = −51.853 d13 = 3.10 r14 = ∞ d14 = 3.10 n7 = 1.51633 ν7 = 64.2 r15 = ∞ Variable Focal Length Separation 3.75 8.60 11.10 d4 11.85 2.69 1.10 d11 1.12 9.04 13.12 Aspheric Coefficients: For r2: R = 2.78636D + 00 K = −6.97078D − 01 B = −4.78910D − 04 C = 1.77019D − 05 D = −1.64098D − 06 For r10: R = 5.32776D + 00 K = −9.08473D − 01 B = −7.94778D − 04 C = −1.82429D − 06 D = −1.44616D − 06
[0063] [0063]FIG. 6 shows the total zooming movement of each of the lens units in the paraxial zone of the numerical example 1. The optical system of the numerical example 1 is of the 2-unit type with the minus-plus refractive power arrangement. The negative first lens unit as the compensator and the positive second lens unit as the variator are moved in differential relation to vary the focal length.
[0064] As is apparent from FIG. 6, in the numerical example 1, the overall lens length (a distance between a lens surface closest to the object side and a lens surface closest to the image side) of the zoom lens is shortest in the telephoto end. In application of the invention to the optical system of the numerical example 1, it is, therefore, desirable that the retraction starts from the telephoto end and, when the power supply is turned on, the zoom lens first moves to the telephoto end.
[0065] FIGS. 7 (A), 7 (B) and 7 (C) are longitudinal section views of the numerical example 1 of the optical system in three zoom positions. The overall lens length of the zoom lens is shortest in the telephoto end as shown in FIG. 6. FIGS. 8 ( 1 ), 8 ( 2 ), 8 ( 3 ) and 8 ( 4 ) to FIGS. 10 ( 1 ), 10 ( 2 ), 10 ( 3 ) and 10 ( 4 ) are graphic representations of the aberrations of the numerical example 1 of the optical system in the respective zoom positions indicated in FIGS. 7 (A), 7 (B) and 7 (C). FIGS. 8 ( 1 ) to 8 ( 4 ) are in the wide-angle end, FIGS. 9 ( 1 ) to 9 ( 4 ) are in a middle focal length position, and FIGS. 10 ( 1 ) to 10 ( 4 ) are in the telephoto end.
[0066] [0066]FIG. 11 shows the total zooming movement of each of the lens units of the numerical example 2. The optical system of the numerical example 2 is of the 3-unit type with the minus-plus-plus refractive power arrangement. The negative first lens unit and the positive second lens unit are moved in differential relation to vary the focal length.
[0067] As is apparent from FIG. 11, in the numerical example 2, the overall lens length of the zoom lens is shortest in a zoom position indicated by A. In application of the invention to the numerical example 2, it is, therefore, desirable that the retraction starts from the zoom position A, and when the power supply is turned on, the zoom lens first moves to the zoom position A.
[0068] FIGS. 12 (A), 12 (B) and 12 (C) are longitudinal section views of the numerical example 2 of the optical system in three zoom positions. The overall lens length of the zoom lens is shortest neither in the wide-angle end nor in the telephoto end, but in a certain zoom position for the middle focal length. FIGS. 13 ( 1 ), 13 ( 2 ), 13 ( 3 ) and 13 ( 4 ) to FIGS. 15 ( 1 ), 15 ( 2 ), 15 ( 3 ) and 15 ( 4 ) are graphic representations of the aberrations in the respective zoom positions shown in FIGS. 12 (A), 12 (B) and 12 (C). FIGS. 13 ( 1 ) to 13 ( 4 ) are in the wide-angle end, FIGS. 14 ( 1 ) to 14 ( 4 ) are in the middle focal length position, and FIGS. 15 ( 1 ) to 15 ( 4 ) are in the telephoto end.
[0069] [0069]FIG. 16 shows the total zooming movement of each of the lens units of the numerical example 3. The optical system of the numerical example 3 is of the 3-unit type with the minus-plus-plus refractive power arrangement. The negative first lens unit and the positive second lens unit are moved in differential relation to vary the focal length.
[0070] As is apparent from FIG. 16, in the numerical example 3, the overall lens length of the zoom lens is shortest in a zoom position indicated by B. In application of the invention to the numerical example 3, it is, therefore, desirable that the retraction starts from the zoom position B, and when the power supply is turned on, the zoom lens first moves to the zoom position B.
[0071] FIGS. 17 (A), 17 (B) and 17 (C) are longitudinal section views of the numerical example 3 of the optical system in three zoom positions. The overall lens length of the zoom lens is shortest neither in the wide-angle end nor in the telephoto end, but in a certain zoom position for the middle focal length. FIGS. 18 ( 1 ), 18 ( 2 ), 18 ( 3 ) and 18 ( 4 ) to FIGS. 20 ( 1 ), 20 ( 2 ), 20 ( 3 ) and 20 ( 4 ) are graphic representations of the aberrations in the respective zoom positions indicated by FIGS. 17 (A), 17 (B) and 17 (C). FIGS. 18 ( 1 ) to 18 ( 4 ) are in the wide-angle end, FIGS. 19 ( 1 ) to 19 ( 4 ) are in a middle focal length position, and FIGS. 20 ( 1 ) to 20 ( 4 ) are in the telephoto end.
[0072] The image pickup apparatus in the present embodiment, when the power supply is turned on, moves the lens from the retracted position to that zoom position which compromises the minimum distance and the high frequency of use. Therefore, the shooting state can be quickly made up. Also, since the zoom position taken when the power supply has been turned off at the last time is stored, the zoom lens can be moved to the stored zoom position, if necessary, when the power supply is turned on again. Therefore, the wasteful driving of the zoom lens can be reduced. So, the consumption of the battery in the image pickup apparatus can be reduced.
[0073] As has been described above, in the lens drive control device and the image pickup apparatus according to the embodiment of the invention, the wasteful lens driving can be reduced when the power supply is turned on.
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A lens drive control device includes a zoom lens, a drive mechanism for driving at least one lens unit which constitutes the zoom lens, a control circuit for controlling the drive mechanism, and a switch for switching between a shooting state and a non-shooting state of the zoom lens, wherein, when the zoom lens is switched from the non-shooting state to the shooting state by the switch, the control circuit causes the drive mechanism to drive the zoom lens to a zoom position other than a wide-angle end.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation of application Ser. No. 08/386,904, filed Feb. 7, 1995, now abandoned, which is a continuation-in-part of U.S. patent application Ser. No. 08/283,110, filed Jul. 29, 1994 now U.S. Pat. No. 5,453,666, which is a continuation-in-part of U.S. patent application Ser. No. 07/980,831, filed Nov. 24, 1992 now U.S. Pat. No. 5,430,354, which is a continuation-in-part of U.S. patent application Ser. No. 07/856,771, filed Mar. 24, 1992, which has issued as U.S. Pat. No. 5,256,946 on Oct. 26, 1993.
BACKGROUND OF THE INVENTION
This invention relates generally to a high intensity discharge (HID) lamp ballast and, more particularly, to an ignition scheme for starting an HID lamp.
An HID lamp generally refers to a family of lamps including high pressure mercury, high pressure sodium, metal halide and low pressure sodium. A conventional ballast for powering an HID lamp includes an ignitor. The ignitor provides high voltage ignition pulses applied to the lamp for starting the latter.
The energy from the high voltage pulses generated by the ignitor are provided to the lamp prior to the lamp entering its glow mode. At the time that the lamp begins to enter its glow mode, the ignitor is shut off. No high voltage pulses are generated during the glow mode. When ignition is successful, the lamp proceeds rapidly through the glow mode to a steady state condition, that is, from a glow discharge to an arc discharge condition between the lamp's electrodes.
The amount of energy required for successful ignition varies and depends on factors such as, but not limited to, partial pressures of the gasses within the lamp. When an insufficient amount of energy is delivered to the HID lamp to ignite the latter, the lamp can become stuck in its glow mode and never reach a steady state (full arc) condition.
Repeated exposure to prolonged periods within the glow mode can damage the HID lamp electrodes. Destruction of the lamp can result.
Accordingly, it is desirable to provide an improved HID ballast having a more reliable HID ignition scheme. The ignition scheme, in particular, should avoid prolonged periods of time within the glow mode.
SUMMARY OF THE INVENTION
Generally speaking, in accordance with a first aspect of the invention, a ballast for lighting a high intensity discharge lamp having a glow mode includes output terminals and an ignitor for producing ignition pulses prior to and at least substantially throughout the glow mode of a high intensity discharge lamp. The ignitor includes a voltage sensor for sensing the voltage across the output terminals and is responsive to the voltage sensor in its production of ignition pulses.
The lamp avoids remaining within the glow mode for an extended period of time by producing ignition pulses not only prior to but also substantially throughout the glow mode of the high intensity discharge lamp. The ignition pulses produced prior to and substantially throughout the glow mode provide sufficient energy for successful takeover, that is, for the lamp to move from a glow discharge to arc discharge operating condition. Damage of the lamp electrodes and consequent lamp destruction based on prolonged duration within the glow mode during start-up is substantially eliminated.
Preferably, the ignitor includes a bilateral switching device such as, but not limited to, a SIDAC having a breakover voltage corresponding to the level of voltage expected across the lamp during its glow mode. The ignitor also can include a capacitor coupled to the bilateral switching device and through which the capacitor discharges at breakover of the bilateral switching device.
In accordance with another aspect of the invention, a lighting arrangement includes an HID lamp having a glow mode and an ignitor for producing ignition pulses prior to and at least substantially throughout the glow mode of the HID lamp.
In accordance with yet another aspect of the invention, a method for starting a high intensity discharge lamp includes the steps of producing ignition pulses prior to the lamp entering its glow mode, continuing to produce ignition pulses substantially throughout the glow mode of the lamp and discontinuing the production of ignition pulses after transition to full arc discharge. The method typically also includes sensing the voltage across the ignitor in determining when to produce the ignition pulses and when to discontinue production of the ignition pulses.
Accordingly, it is an object of the invention to provide an improved ignition scheme for more reliably starting an HID lamp.
It is another object of the invention to provide an improved HID ballast which provides sufficient energy to the HID lamp so as to avoid the latter remaining in its glow mode for a prolonged period of time during start up.
Still other objects and advantages of the invention, will, in part, be obvious, and will, in part, be apparent from the specification.
The invention accordingly comprises several steps in the relation of one or more such steps with respect to each of the others, and the device embodying features of construction, combination of elements and arrangements of parts which are adapted to effect such steps, all is exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWING
For a fuller understanding of the invention, reference is had to the following descripion taken in connection with the accompanying drawing in which FIG. 1 is a lighting system in accordance with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1, a ballast 10 is connected through a pair of input terminals 33 and 36 to an A.C. source 20. Ballast 10 provides power through a pair of output terminals 39 and 42 to an HID lamp 40.
Ballast 10 includes an autotransformer 60 having a primary winding 60 with a tap 63. Winding 60 is connected to input terminals 33 and 36. A capacitor 66 is connected between tap 63 and one end of a ballast winding 65. Ballast winding 65 which is magnetically coupled to primary winding 60 includes a first tap 76 and a second tap 77. The portion of ballast winding 65 between taps 76 and 77 is commonly referred to as an ignitor winding 79. The other end of ballast winding 65 is connected to output terminal 39.
Ballast winding 65 serves to limit/control the level of current flowing through lamp 40 when the latter is lit. A SIDAC 89 and a capacitor 92 are connected respectively to taps 76 and 77. SIDAC 89 and capacitor 92 are also connected through the serial combination of an inductor 95 and a resistor 96 to the junction joining primary winding 60, input terminal 36 and output terminal 42 together. Ignitor winding 79, SIDAC 89, capacitor 92, inductor 95 and resistor 96 serve together as an ignitor (i.e., starting circuit) 80. Ignitor 80 can be integrally connected to ballast winding 79. Alternatively, SIDAC 89 and capacitor 92 can be detachably connected to tap points 76 and 77, respectively.
Ballast 10 operates as follows. Power is supplied from A.C. source 20 to input terminals 33 and 36 of ballast 10. The voltage produced by A.C. source 20 is insufficient to ignite/start lamp 40, the latter of which requires ignition (starting) pulses. The ignition pulses are provided by ignitor 80. More particularly, as current flows through capacitor 92, inductor 95 and resistor 96, capacitor 92 charges to the breakover voltage of SIDAC 89.
The breakover voltage is chosen so as to correspond to the characteristic glow discharge voltage of lamp 40. In other words, the breakover voltage is chosen so as to reflect when the lamp is about to enter its steady state mode of operation.
Once the breakover voltage is reached, SIDAC 89 switches from its previous OFF-state to its ON-state. Capacitor 92 now discharges through ignitor winding 79 and SIDAC 89 resulting in a voltage pulse produced across ignitor winding 79. Through transformer action (i.e. ballast 65 acting as an autotransformer), a high voltage pulse is developed across output terminals 39, 42. The cyclical charging and discharging of capacitor 92 produces a series of high voltage pulses across output terminals 39, 42. By associating the breakover voltage of SIDAC 89 with the glow mode of lamp 40, ignition pulses are provided by ignitor 80 prior to and substantially throughout the glow mode of lamp 40. During transition from glow arc to full arc, the voltage across lamp 40 temporarily increases. Following transition into a full arc condition (discharge), the voltage across lamp 40 sufficiently drops to turn OFF SIDAC 89. Accordingly, after transition to full arc discharge, ignitor 80 is shut OFF.
SIDAC 89 serves as a voltage sensor for sensing the voltage across output terminals 39 and 42 of ballast 10. Ignitor 80, in response to SIDAC 89 cyclically turning ON and OFF, provides a sufficient amount of energy for successful takeover of lamp 40. In particular, the continuous production of ignition pulses prior to and at least substantially throughout the glow mode avoids lamp 40 remaining within the glow mode for an extended period of time. Damage of the lamp electrodes and consequent lamp destruction based on prolonged duration within the glow mode is substantially eliminated.
For example, when lamp 40 is of a metal halide type, nominally rated at 150 watts, 95 volts with SIDAC 89 having a breakover voltage of between about 110-125 volts, a voltage pulse of about 110-125 volts is applied across ignitor winding 79. A voltage of about 1800 to 3500 volts is developed across output terminals 39, 42 for starting the lamp. The SIDAC breakover of about 110-125 volts corresponds to a lamp voltage of between 150 v-200 v, respectively. The cycle of charging capacitor 92 until reaching the SIDAC breakover voltage resulting in the generation of a high voltage pulse applied to lamp 40 is repeated prior to and at least substantially throughout the glow mode of lamp 40. Ignitor 80 is shut OFF at the end of the glow mode.
More particularly, once lamp 40 is lit, the voltage across SIDAC 89 drops below its breakover voltage. Ignitor 80 is no longer able to produce a voltage pulse across ignitor winding 79. In other words, as long as lamp 40 remains lit, ignitor 80 will produce no additional voltage pulses.
In accordance with the preferred embodiment of the invention, ballast 30 is a 150 watt metal halide constant wattage autotransformer (CWA) available from Advance Transformer Company of Rosemont, Ill. as part no. 71A5486. Capacitor 66 is nominally rated at 22.5 μf, 240 volts. SIDAC 89 is available from Shindengen Electric Mfg. Co., Ltd. as Part No. K1V12 and has a nominally rated breakover voltage of about 110-125 volts. Capacitor 92 is nominally rated at about 0.33 microfarads. Lamp 40 is a high intensity discharge type, such as but not limited to, a 150 watt, 95 volt metal halide type. Inductor 96 typically includes two serial connected coils, each nominally rated at 22 millihenries. Resistor 95 is nominally rated at 3.5K ohm.
As now can be readily appreciated, the invention provides an improved ignition scheme in which ignition pulses are produced prior to and at least substantially throughout the glow mode of lamp 40. Prolonged periods of time within the glow mode are substantially eliminated by providing sufficient energy for successful takeover lamp 40.
It will thus be seen that the objects set forth above and those made apparent from the preceding description, are efficiently obtained and since certain changes may be made in the above construction without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
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An ignition scheme for starting a high intensity discharge lamp requiring energy in the form of ignition pulses to be provided to the lamp prior to and substantially throughout the glow load of the lamp. An ignitor includes a bilateral switching device such as, but not limited to, a SIDAC having a breakover voltage corresponding to the lamp voltage during the lamp glow mode. The ignition scheme substantially eliminates the lamp remaining in its glow mode for a prolonged period of time thereby minimizing the possibility of lamp destruction from damage to the lamp electrodes.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to file systems for computers, and more particularly relates to a file system which employs no inter-related metadata.
2. Description of Related Art
Modern file systems have an accepted problem that limits their performance, reliability, availability, and flexibility. The problem is that the file system's metadata is composed of inter-related structures on the physical media. Modern file systems use this metadata to organize the user data and to keep track of resources within the file system.
This inter-related metadata can become out-of-sync with itself because of system failures or software "bugs". The out-of-sync metadata can lead to data corruption and system failures. The task of keeping the metadata in sync with itself is complex and limits the performance, reliability, availability, and flexibility of modern file systems.
There have been a number of books and treatises written on operating systems such as the UNIX® 1 operating system. These include excellent summaries of the file systems employed by the operating system. For example, see "The Design and Implementation of the 4.3BSD UNIX® Operating System" by Leffler, McKusick, Karels and Quarterman.
It is a study in and of itself to understand the complexity and the amount of internal "bookkeeping" which is required to properly update, create and maintain a file system for a complex operating system. By way of example only, the UNIX® file system is summarily described below with reference to FIGS. 1A & 1B of the drawings.
In the UNIX® file system, the internal representation of a file is given by an "inode" which contains a description of the disk layout of the file data and other information such as the file owner, access permissions, and access times. The term inode is a contraction of the term "index node" and is commonly used in literature on the UNIX® system. Every file has one inode, but it may have several "names", all of which map into the inode. Each name is called a "link".
A computer process during the execution of a program requires the interpretation of a pattern of bytes that the CPU interprets as machine instructions (called "text"), data, and stack. Many processes appear to execute simultaneously as the kernel schedules them for execution, and several processes may be instances of one program. When a "process" refers to a file by name (including its'path, sometimes referred to as a pathname), the kernel parses the file name one character at a time, checks that the process has permission to search the directories in the path, and eventually retrieves the inode for the file. For example, if a process calls open "/fs4/bjf/sun/sourcefile", the kernel retrieves the inode for "/fs4/bjf/sun/sourcefile". When a process creates a new file, the kernel assigns the file an unused inode. Inodes are stored in the file system, but the kernel, when manipulating files, reads them into an inode table contained in memory.
As illustrated in FIG. 1A, the kernel contains two other data structures, the "file table" and the "user file descriptor table". The file table is a kernel structure, which keeps track of (1) the byte offset in the file where the user's next read or write will start and (2) the access rights allowed to the opening process. The user file descriptor table is allocated for every process, and it identifies all open files for a process. When a process opens or creates a file, the kernel allocates an entry from each table, corresponding to the file's inode. Entries in the three structures, i.e. user file descriptor table, file table, and inode table, maintain the state of the file and the user's access to it. The kernel returns a file descriptor for the open and read system calls, which is an index into the user file descriptor table. When executing read and write system calls, the kernel uses the file descriptor to access the user file descriptor table, follows pointers to the file table and inode table entries, and, from the inode, finds the data in the file. For now, suffice it to say that use of the three tables briefly described above allows diverse degrees of sharing access to a file.
The UNIX® file system has the structure depicted in FIG. 1B, and briefly described below. Referring now to FIG. 1B, the "boot block" occupies the beginning of a file system, typically the first sector, and as is conventional, may contain the "bootstrap" code that is read into the machine to initialize the operating system. Although only one boot block is needed to boot the system, every file system has a (possibly empty) boot block.
The "super block" describes the state of a file system, the size of the file system, the number of free blocks in the file system, a list of free blocks available on the file system, the index of the next free block in a list of free blocks, the size of the inode list, the number of free inodes in the file system, a list of free inodes in the file system, the index of the next free inode in the free inode list, lock fields for the free block and free inode lists, and a flag indicating that the super block has been modified.
The "inode list" is a list of inodes that follows the super block in the file system. Conventionally, administrators specify the size of the inode list when configuring a file system. The kernel references inodes by index into the inode list. One inode is the "root inode" of the file system: it is the inode by which the directory structure of the file system is accessible after execution of the "mount" system call.
The "data blocks" start at the end of the inode list and contain file data and administrative data. An allocated data block can belong to one and only one file in the file system.
Moreover, there are numerous other parts of the typical UNIX® file system which complicate and make burdensome the file structure, integrity and other aspects of record keeping for the file system. For example, directories are the files that give the file system its hierarchical structure. In the instance of a UNIX® operating system, directories are important in converting a file name to an inode number.
SUMMARY OF THE INVENTION
In accordance with this invention, the above problems have been solved by accessing a "chunk" in a storage medium by hashing an access tag. A chunk is a predetermined number of bytes or blocks. A chunk may be any size, but in a given file system, all chunks are the same size. The chunk is divided into two portions, tag and data. The data is data usually for part of a file, but a small file might be small enough to be contained in one chunk. When the chunk is stored in a storage medium, the tag is referred to as a storage tag. The storage tag is made up of a pathname, filename and path to a file, and a logical offset, the number of bytes or blocks from beginning of file to the chunk.
In operation, an access tag is received from a user requesting access to a "chunk" in a storage medium. The access tag is identical to the storage tag of the chunk being requested by a user. The pathname and the logical offset in the access tag is hashed to generate a suggested location for the storage of the chunk in the storage medium. The storage medium is searched from the suggested location to locations proximate to the suggested location to look for a match between the storage tag and the access tag to locate the chunk requested by the user.
As a further feature of the invention, the searching operation is accomplished by reading the storage tag of the chunk at the suggested location, comparing each storage tag read by said reading step with the access tag and indicating a tag match if the storage tag matches the access tag, detecting an available-for-write chunk if said comparing step has not indicated a tag match and the chunk is empty, and scanning in a preset search pattern from the suggested location to a new storage location to read the storage tag of a new chunk. The steps of comparing, detecting and scanning are repeated until a tag match or an available-for-write chunk is detected.
In accordance with the file system of the present invention, the file is initially written to a location computed by hashing the pathname and the logical offset. The placement of the data is always read first to ensure that there isn't a conflicting chunk, i.e. one that has been previously written, in the place where the data is to be written. When locating the data for reading, modifying, or updating it, the pathname and the logical offset must be hashed with the same hashing operation employed for writing the file. The hashing operation generates a hint for the file location. Once the hint is provided, the Tagged Hashed File System (THFS) searches the disk (or if in cache memory) from that point on until it finds a match in the tag with the pathname and logical offset.
The THFS has many useful characteristics in its availability, reliability and flexibility. It is more available than other file Systems because a Tagged, Hashed File System is designed to avoid being in an inconsistent state. The THFS can be accessed immediately without a lengthy check-and-repair cycle. Moreover, the THFS is kept in a consistent state without complex logging or journaling technology. The THFS of the present invention is more reliable because the "good" portions of the user's data can be easily recovered even in the event of partial media failure or partial file system corruption. The THFS is much more flexible because it is only loosely tied to the physical media. Upstream and downstream caching at the block level is easily implemented. There is no requirement that the system search on only one piece of media for the pathname and offset found in the tag. For example, the system may easily check local disk(s), server's disk(s), the Hierarchial Storage Subsystem, and/or the Backup Subsystem. Additionally, the system could easily cache desired blocks of a file with a particular pathname wherever it wanted.
A great advantage of the THFS of the present invention is that since there is no metadata, no journal is required thereby eliminating the complexities of a journaling type file system. Additionally, while conserving disk space, which makes the file system of the present invention more useful, implementation is fast and easy.
Another major advantage of the THFS is that it easily survives media corruption without "hanging" in the file system i.e., for example, there could be disk damage, and only thing that would be hurt or possibly lost is where the damage had occurred. Thus the THFS of the present invention does not have to rely upon inter-related metadata to insure either writes or reads.
Another very distinct advantage is that with very large systems, e.g. 200 GByte systems, where system boot may take 2+ hours, a system boot with the file system of present invention takes very little time, i.e. less than 5 minutes.
In all these ways, the THFS of the present invention is useful as a replacement for the more complex, metadata bound or constrained file system.
A more complete understanding of the invention may be had by referring to the following description taken in conjunction with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWING(S)
FIG. 1A is a schematic & abbreviated representation of the file descriptors, file table and inode table of a portion of the UNIX operating system's file system.
FIG. 1B is a schematic & abbreviated representation of the file system layout of the UNIX® operating system's file system.
FIG. 2A is a schematic representation of a group of chunks, and in which each chunk has a tag or header, and user's data.
FIG. 2B illustrates the primary logical operations of a preferred embodiment of the invention.
FIG. 2C illustrates the search operation included in FIG. 2B.
FIG. 3 is a data processing system which provides the operative elements to perform the logical operations of the invention.
FIG. 4 is a flow chart demonstrating an example hashing operation to aid in file location/placement in accordance with the present invention.
FIG. 5 is a flow chart exemplifying the read process of the tagged, hashed file system.
FIG. 6 is a flow chart illustrating the write process of the tagged, hashed file system.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In accordance with a preferred embodiment of the invention, the tagged, hashed file system (THFS) writes and reads user data in "chunks," each chunk contains user data and a tag. The size of a chunk is a preset number of bytes or blocks. All chunks in the THFS are the same size. The tag identifies the chunk. The same tag is hashed to identify the location of storage space in storage media for the chunk. The media may be either non-volatile storage or volatile memory (as the case may be). When accessing such data, a hashing operation hashes the tag to "hint" or suggest the location of the chunk to be written/read. The chunk is located (if previously written) by looking at the suggested location for the tag of the chunk. The tag is a name (hereinafter referred to as pathname, because it includes the filename and the path for finding the file as part of the name) plus an offset in bytes or blocks from the beginning of file.
Referring to FIG. 2A, a user's file is broken up into chunks 50, each chunk 50 has a tag portion 55 and a user's data portion 60. For our examples, assume a chunk size of 1024 bytes. The tag 55 contains two items of information: (1) the pathname (filename +full path information including subdirectories etc.) and (2) the offset in blocks or bytes that the chunk is located from the beginning of the file. (NOTE: A block may be any convenient size, usually in most systems, e.g. UNIX®, DOS, OS/2® etc., some multiple of 512 bytes, e.g. 1024 . . . . 4096 etc.) For example, suppose the pathname was "/a/b/c", and the data chunk desired by the particular application program was fifty (50) blocks from the beginning of file. Then the tag 55 is "/a/b/c, 50". The file offset could also be set forth in terms of "bytes" offset from the start of the file. This is the more typical or conventional way of data-within-a-file designation, depending upon the operating system or application program protocol. The byte offset, in this example, would be 51,200 bytes (50 times 1024).
With the above file system and chunk storage structure in mind, the primary logical operations for accessing a chunk of a file in accordance with a preferred embodiment of the invention are shown in FIG. 2B. The access operation begins at logical operation 33 which receives an access tag in an access (read/write) request message from the user. The access tag is identical to the storage tag on the chunk in the storage medium, i.e. the chunk the user is requesting access to. Operation 34 then hashes the access tag to generate a suggested location in the storage medium where the chunk can be found. Any number of hashing operations may be selected to perform operation 34. (One embodiment for the hashing operation is described hereinafter with reference to FIG. 4.) The search operation 35 searches in a search pattern from the suggested location for the chunk to other storage locations for chunks proximate to the suggested location. The search operation is looking for a tag match, i.e. a match between the access tag in the access request and the storage tag in a chunk at a storage location in the storage medium.
FIG. 2C illustrates the logical operations that make up search operation 35 in FIG. 2B. The search operation begins at step 36 which reads the storage tag of the chunk at the suggested location received from the hashing operation 34 (FIG. 2B). Decision operation 37 compares the access tag to the storage tag. If there is a match, the search operation branches "Yes" to operation 38. Access location operation 38 reads or writes the chunk at the storage location found by the tag match.
If there is no tag match, the search operation branches "No" to decision operation 39. Decision operation tests the user data space 60 (FIG. 2A) in the chunk to see if the chunk is empty. If the chunk is empty, the chunk is available for writing. If the chunk is not empty, decision operation branches "No" to scanning operation 40. Scanning operation 40 then scans the storage medium in a preset pattern to move the read/write transducer of the storage medium to a new location. This new location will be chosen by the preset pattern to be proximate to the location just read and rejected through operations 37 and 39. The best choice for the scan pattern and the physical proximity of the new location to the rejected location depends on the efficiencies of the scanning mechanism. Proximity in time of access may be more relevant to the choice than proximity in physical space on the storage medium. At the new location, operation 41 reads the storage tag of the chunk, and the storage operation loops back to decision operation 37 to compare for a tag match.
If there is no tag match decision operation 39, detects whether the chunk is empty as described above. If the chunk is empty, the search operation branches "Yes" to decision operation 42. Decision operation 42 detects whether the access request is a write operation. If the access operation is a read operation, the search operation branches "No" to operation 43. Operation 43 sends an error message back to processor/user that the chunk is "Not found." If the access operation is a write operation, the process branches "Yes" from decision operation 42 to operation 44.
Operation 44 writes data from the user application to the chunk in the storage medium. Then update operation 45 changes the storage tag at the chunk just written to the access tag in the access (write) request. Thereafter, the newly written chunk can be accessed using the access tag.
In summary, the search operation starts at the suggested location. If it does not find a tag match or an empty chunk at the suggested location, it scans in a preset pattern to new locations until it does find a tag match or an empty chunk. If the search finds a tag match, it accesses the chunk. If the search finds an empty chunk and the access is a read request, the search returns a "not found" message. If the search finds an empty chunk and the access is a write request, the write data is written to the empty chunk and the storage tag of the newly written chunk is updated to match the access tag.
The operating environment in which the present invention is used encompasses a general distributed computing system, wherein general purpose computers, workstations, or personal computers are connected via communication links of various types, in a client-server arrangement. This is done so that programs, data and the like, many in the form of objects, may be made available by and to various users on the system.
Some of the elements of a data processing general purpose workstation computer 20 are illustrated in FIG. 3, wherein a processor 21 is shown, having an input/output (I/O) section 22, a central processing unit (CPU) 23 and a memory section 24. The I/O section 22 is connected, inter alia, to a keyboard 25, a display or monitor 26, and non-volatile memory. The non-volatile memory may include a disk storage unit 29 (e.g. a hard drive), a CD-ROM or optical disk drive unit 27 and in the illustrated instance a floppy disk drive 30. (As is conventional, the drive controllers may be contained in the processor 21 or in the drives themselves). The CD-ROM unit 27 can read/write a CD-ROM medium 28 which typically contains programs and data, while the floppy disk drive 30 can read and write floppy disks 31. The computer program products which may be employed for carrying out the methods and apparatus of the present invention, may reside in the memory section 24, on disk storage unit 29, on the CD-ROM 28 or floppy disk 31 of such a system. Examples of such systems include SPARC systems offered by Sun MICROSYSTEMS, Inc., personal computers offered by IBM Corporation and by other manufacturers of IBM-compatible personal computers, and systems running the UNIX® or other operating system.
In another embodiment of the invention in FIG. 5, assume that the data for the file with the pathname "/a/b/c" was already on disk and the operator-user desires to get the data for modification, addition, etc. the process outlined in FIG. 5 is followed. Assume that the data processing system 20 of FIG. 3 has been initialized and is up and running. At the outset, the operator/user of the data processing system illustrated in FIG. 3, and described heretofore, will call up an application program (e.g. a word processing program), as by the keyboard 25 via the computer 21, from the hard disk 29 or the CD-ROM drive 27 and CD-ROM 28, or even the floppy disk 31. Then assume the operator calls up a file with the pathname "/a/b/c," and the application program is programmed to give the offset at the end of the user's file which for example purposes is in block 50. When the operator/user calls up the file with the pathname "/a/b/c", the pathname is placed on the screen 26a of the monitor 26 by the system, and as is conventional, the operating system reads into memory 24 the file with the pathname "/a/b/c". This is accomplished, as shown in FIG. 5, by first reading at process step 65, the pathname and offset (/a/ b/c, 51,200). By a simple calculation, as in process step 66, the offset 51,200 is converted to a chunk number, in the illustrated instance, 51,200/1024=50.
The pathname and offset are utilized in a hashing operation to give to the file system a convenient starting place (a "hint" or suggestion) to look for a chunk with tag containing the desired pathname and offset. This hashing function takes place at process step 70 in FIG. 5. To this end, the hashing operation may be of any convenient type, e.g. a quadratic type, or a simple type, depending only upon the user's wishes and how well it works from a time-to-access the file basis.
Turning now to FIG. 4, a simple hashing operation is illustrated. However, it should be understood that the hashing operation may be of any convenient type which should allow for rapid access to the desired chunk containing the user data block of the sought-for file. For chunk 50 of a file with a pathname /a/b/c, operation 71 sums the ASCII value of the characters in the file's pathname. In the example pathname, "/a/b/c", the ASCII values are: /=47, a=97, b=98, c=99. Therefor, 3 times 47=141, and 141+97+98+99=435. Operation 72 then adds the chunk number of the file offset 50 to the sum from operation 71, e.g. 435+50. Decision operation 73 tests whether the sum, 485, from operation 72 is less than the file system size. If the file system size is 1024 blocks, the hashing operation branches "Yes" from decision operation 73 to operation 75. Operation 75 uses sum 485 as a "hint" or a suggestion as to where to start looking for the file with the pathname "/a/b/c" and an offset of chunk 50.
If the sum is greater in size than the size of the file system, hash operation branches "No" from operation 73 to operation 74. Division operation 74 divides the sum from operation 72 by the file system size and use the remainder as a "hint" or suggestion as to where to start looking for the file with the pathname "/a/b/c" and an offset of chunk 50. Operation 75 would then send the remainder onto the search operation as the suggested location for the chunk.
As an example of the above situation set forth in the last hashed process step, assume the pathname is "/sun/bjf/fuller" and the offset is still 50. The sum of the ASCII code for this pathname is 1337. (/=47, s=115, u=117, n=110, b=98, j=106, f=102, 1=108, e=101, r=114). Summing the ASCII code for that pathname and offset or chunk number (1337+50)=1387, and dividing that number by 1024 equals 1 plus a remainder of 363. Therefore, the "hint" or suggestion is to "start looking at chunk 363".
After the Hash Function gives a "hint" as to where the file is located, the disk controller causes the head of the disk drive to seek the suggested location of the chunk on the disk, and as shown at process step 78, the disk (or if in memory, the memory) is read, using the hint as a suggested starting point. A search routine in the file system insures that the disk is searched in a predetermined pattern. The search pattern is the same for which the pattern was employed for finding a blank or unused block for a write is found. The search can be circular, (i.e. after the "hint" block tag is read, then the first block below the "hint" block and then the first block above the "hint" block, and then the second block above then the second below and so on) or it can be in consecutive chunk order or any other predetermined and consistent pattern until one of two situations occurs, either a tag is read matching the pathname and offset or a predetermined event occurs which signals to stop the search. Such an event can be the reading of a location and chunk with either a blank block or unused tag. A blank block or a block with an unused tag is a block which is available for writing. As shown, if a "hit" or tag match occurs, the data is returned to the system, as in step 80. In the loop of "No" hit, is a decision step 81 which determines if a blank block is read, or a tag of a block is read having no pathname and offset. If that occurs the search is terminated, and a message indicating such, is returned to the operator-user's screen 26a, e.g. at step 82, that "the file was not found".
When a file is to be put to disk, e.g. the disk drive 29 or on the disk 28 associated with the CD-ROM drive 27, the logical operations of FIG. 6 are followed. Assume that the same word processor application is active (running on the data processing system 20), and the operator-user decides to save a new file "/a/b/c", with the end of file being at offset 50. When he enters the command "save" the write process commences as at process step 85. If the offset is given as bytes, the same conversion occurs as in FIG. 5 in process step 66, and as discussed above. The hash function step 70 then is commenced and the same operation heretofore described and set forth above with reference to FIG. 4 is employed to give a "hint" as to the proper location for read/write.
Because there is no related metadata to indicate that the file is or is not already in existence, the first function is to check if such a file already exists. Thus a read function occurs and loops to check whether or not a block exists with the tag containing the pathname and offset of the file. As long as the search for a file with a tag having the same pathname and offset occurs in the same pattern as set forth above and described relative to FIG. 5, the search continues until the file is found or an "empty" block (a block free for being written to, in this context, is considered an empty block) is found. If an empty block is found, then the file is not present and a write will occur as shown by the decision step 81 and the process step 83. The tag of the written block will contain the filename and the offset. In the event that a file is found with the same filename and offset (decision step 79 returns "Yes"), then a message may be returned to the operator user on screen 26a of the monitor 26, for example, as shown in process step 84, "ADD TO OR OVERWRITE FILE?" The operator-user can then make a determination to overwrite the existing file or stop, and command a "save" for a new or different file name etc.
The THFS of the present invention is much more flexible because it is only loosely tied to the physical media. Upstream and downstream caching at the block level is easily implemented. In the previous example, there is no requirement that the system search on only 1 piece of media for block 50 of file "/a/b/c" or "/sun/bjf/fuller". For example, the system may easily check local disk(s) (such as multiple floppy disks 31), or CD-ROM disks 28, server's disk(s), a hierarchial storage subsystem, and/or a backup subsystem. Additionally, the system could easily cache blocks of a file wherever desired.
The THFS of the present invention is more available than other file Systems because a Tagged, Hashed File System is never in an inconsistent state. The simple but elegant file system of the present invention can be accessed immediately without a lengthy check-and-repair cycle. Moreover, the THFS heretofore described is kept in a consistent state without complex logging or journaling technology.
In addition, the THFS of the present invention is more reliable because the "good" portions of the user's data can be easily recovered even in the event of partial media failure or partial file system corruption.
Although the invention has been described with a certain degree of particularity, it should be recognized that elements thereof may be altered by person(s) skilled in the art with out departing from the spirit and scope of the invention as hereinafter set forth in the following claims.
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In the tagged, hashed file system, each finite portion of a file of the user's data is tagged with a pathname (filename and path) and a logical offset of the data within the file. A hint, as to where the portion is located in storage in the THFS, is computed by hashing the pathname and the logical offset. Once the hint is provided, then the THFS commences to search storage from the location suggested by the hint until it finds a match between the tag on the portion with the pathname and logical offset. When a portion is to be written, the intended location for placement of the portion must be read to ensure that it is available for writing, i.e. empty. If the location is not available, then a search must be made for the closest available (empty) location, and the user data is written there. If during a read operation a matched tag is not found until an empty area is read, the search will terminate, and the user application will be notified that no file was found.
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BACKGROUND OF THE INVENTION
This invention relates to sputtering devices which deposit a metallic film on the surface of a workpiece by the utilization of a cathode sputtering phenomenon which occurs in a glow discharge.
In general, in sputtering devices, the cathode sputtering phenomenon accompanying glow discharge, that is, the phenomenon that the material of a cathode is vaporized into metallic atoms or a mass of metallic atoms by the bombardment of gas ions thereto, a part of the atoms being scattered, is utilized. The metallic atoms thus scattered are adhered to the surface of a workpiece positioned in the vicinity of the anode thereby to form a metallic film thereon.
A feature of such sputtering is that the lower the pressure of the gas atmosphere in which the sputtering is effected, the smaller the number of chances for the metallic atoms emitted from the cathode to collide with the residual molecules between the electrodes is, and at the same time the finer the finish of a metallic film obtained by depositing the metallic atoms arriving directly at the workpiece is. That is, the pressure of the gas atmosphere should be as low as possible to improve the quality of the metallic film deposited on the work piece.
In conventional sputtering devices of this type, conditions for effectively conducting sputtering in a glow discharge are experimentally determined by the nature and state of the gas and the cathode material employed therein, and especially the pressure of the gas, which must be maintained at a certain value (of the order of 1-2×10 -2 Torr in direct current glow discharge, in general) for the occurrence of a glow discharge. Thus, lowering the pressure of the gas is limited.
Furthermore, in conventional sputtering devices, electrons emitted from the target during the sputtering collide with the anode thereby increasing the temperature of the latter. The temperature of the workpiece placed near the anode is also increased by the radiant heat from the anode. Therefore, the heat stability of the workpiece must be taken into consideration.
SUMMARY OF THE INVENTION
Accordingly, a primary object of this invention is to provide a sputtering device in which the direction of a magnetic field orthogonally crosses that of an electric field. A magnet is disposed within the target so that the magnetic force lines of the magnet start from the surface of the target and return to the same in an electrode space (defined later), and sputtering is effectively performed under electromagnetic action even in a gas atmosphere of extremely low pressure.
Another object of the invention is to provide a sputtering device in which a target is uniformly sputtered, and therefore the distribution in thickness of a metallic film deposited on a workpiece is uniform.
A further object of the invention is to provide a sputtering device which provides excellent cooling in order to carry out sputtering at low temperature.
A still further object of the invention is to provide a sputtering device in which the structure of the permanent magnet is simple and the handling of the same is also simple so that no difficulties are caused during sputtering.
The specific feature of the sputtering device according to this invention resides in that cylindrical cathode and anode electrodes are coaxially disposed and a magnetic field is generated orthogonal with the electric field thereby controlling the drift motion of electrons so that they do not reach the anode unless they lose their energy upon colliding with gas molecules. In order to cause the drift motion of the electrons to occur in a particular region, one or a plurality of magnets having a radial magnetic field are disposed in parallel to the target or cathode (perpendicularly to the electric field).
The sputtering device thus described has the following merits:
(1) Formation of a metallic film on a workpiece can be achieved in a high vacuum (less than 2-3×10 -4 Torr in direct current discharge).
(2) The amount of the temperature rise of the workpiece is less. It is said that a main cause of the temperature rise of the workpiece is the flow of electrons into the anode (which sometimes serves as a base plate).
(3) Deposition rate is high. Since the temperature rise of the workpiece is less, as was described above, a large electric power can be applied to the sputtering device, and therefore a high deposition rate can be obtained.
(4) The structure of the target is simple:
(a) Since the electric discharge is effected in a high vacuum, insulation for the target can be simple. Thus, it is unnecessary to provide a dark space shield, or the like.
(b) The discharge is effected only at places where the electric and magnetic fields are crossed orthogonal 14. Therefore, the cathode is covered with a deposition material only at the portions where the discharge is effected.
(5) Cooling of the electrodes can be readily achieved.
(a) The cathode can be cooled with water by the conventional water-cooling method if a permanent magnet is employed.
(b) One or several rods disposed in parallel to the cathode and perpendicularly to the direction of the drift motion of the electrons can be used as anodes. If these anodes are replaced by pipe-shaped anodes, they can be readily cooled with water. Furthermore, since the energy of the electrons is small when they have reached the anodes, the amount of water necessary for cooling the anode can be relatively small.
The nature, principle and utility of this invention will become more apparent from the following detailed description and the appended claims when read in conjunction with the accompanying drawings in which like parts are designated by like reference characters.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIGS. 1(a) and 1(b) are respectively a vertical sectional view and a horizontal sectional view illustrating a first example of a sputtering device according to this invention;
FIGS. 2(a) and 2(b) are respectively a vertical sectional view and a horizontal sectional view illustrating a second example of the sputtering device according to the invention;
FIG. 3 is a vertical sectional view showing a third example of the sputtering device according to the invention;
FIG. 4 is a graphical representation indicating the distribution in thickness of a metallic film deposited on a workpiece by the sputtering device shown in FIGS. 1(a) and 1(b);
FIG. 5 is also a graphical representation indicating the distribution in thickness of a metallic film deposited on a workpiece by the sputtering device shown in FIG. 3;
FIG. 6 is a vertical sectional view illustrating a fourth example of the sputtering device according to the invention; and
FIG. 7 is a vertical sectional enlarged view showing the erosion profile of a target incorporating a magnet, as shown in FIGS. 1(a) and 1(b).
DETAILED DESCRIPTION OF THE INVENTION
A first example of a sputtering device, as shown in FIGS. 1(a) and 1(b), comprises a base plate 1 and a cylindrical cover 2 which is hermetically and detachably mounted on the base plate 1 by the use of packing 101, to provide a vacuum container 3. In this container 3 there are coaxially provided a target (or cathode) 4, anodes 5, and workpieces 6.
The target 4 is obtained by plating or spraying with target material 41 such as chrome (Cr) the outer surface of cylinder 8 of non-magnetic material which is mounted through an insulator 7 on the central portion of the base plate 1, or by winding a wire or strip of target material 41 such as molybdenum (Mo) or tungsten (W) around the cylinder 8. If the cylinder 8 is made of material such as aluminum (Al), copper (Cu) or stainless steel (SUS), no treatment such as described above is necessary, that is, it can be used, as it is, as the target 4.
In this example, the anodes 5 are rod-shaped electrodes provided on the base plate 1. The rod-shaped electrodes 5 are disposed in such a manner that they surround the target 4. Furthermore, the workpieces 6 are placed in such a manner that they surround the electrodes 5.
In the cylinder 8, there is provided a cylindrical magnet 9 having a through-hole along its axis in such a manner that the direction of the magnetic field H of the magnet 9 crosses orthogonally the direction of the electric field E between the electrodes 4 and 5.
Packings 10 are provided between the base plate 1 and the insulator 7, and between the insulator 7 and the bottom of the cylinder 8 so that the inside of the cylinder is maintained airtight. A cooling-water inlet pipe 12 for introducing cooling water W into the cylinder 8 and a cooling water outlet pipe 11 for discharging the cooling water W out of the cylinder 8, as shown in FIG. 1(a), penetrate into the cylinder 8 through the base plate 1, the outlet pipe 11 extending through the through-hole of the magnet 9 so that the cooling water is circulated in the cylinder 8 so as to cool the target 4 whose temperature is increased by bombardment of gas ions.
Furthermore, in the base plate 1 there are provided an air suction port 14 to which a vacuum pump 13 is connected, and a gas injection port 17 to which a gas cylinder 15 is connected through a control valve 16.
The operation of the sputtering device thus described will bow be described.
First, the vacuum pump 13 is operated to evacuate the vacuum container 3. Then, the vacuum container 3 is filled with the gas from the gas cylinder 15; however, the gas in the vacuum container 3 is maintained at a predetermined pressure at all times by adjusting the control valve 16 of the gas cylinder 15.
If, under this condition, a suitable exciting voltage V is applied across the target 4 and the anodes 5 to provide a glow discharge therebetween, the cathode sputtering phenomenon described before takes place, that is, the target atoms sputtered are deposited on and adhered to the surfaces of the workpieces 6, thus forming a film on the workpiece which has strongly adhered thereto.
In this operation, the magnetic field H of the magnet 9 causes a force F along the electrodes 4 and 5 provided in the form of coaxial cylinders to act on the electrons which have been emitted from the target 4 by the bombardment of the gas ions, as a result of which the electrons are enclosed in a space defined by the electric field formed by the electrodes 4 and 5 and the magnetic field of the magnet 9 (hereinafter referred to as "electrode space" when applicable), and are moved along the electrodes. Accordingly, the density of the electrons in the electrode space is increased, and therefore the glow discharge becomes vigorous and sputtering is effected more actively.
Thus, even if the pressure in the vacuum container 3 is reduced from 1×10 -2 Torr to a value of the order of 1×10 -4 , sputtering can be carried out at high efficiency. Furthermore, in the sputtering device according to the invention, the number of electrons (emitted by the cathode) which collide with the workpieces is considerably reduced, and the temperature rise of the workpieces is also considerably reduced.
A second example of a sputtering device according to this invention is shown in FIGS. 2(a) and 2(b). Its operating principle is completely the same as that of the first example described above.
In the second example, a workpiece holder 18 is provided at the central portion of a vacuum container 3 made of non-magnetic insulating material, and a target 42 and a hollow cylindrical magnet 91 (both being cylindrical) surround the workpiece holder 18. More specifically, the target 42 has outer and inner walls forming a cylindrical chamber 19 in which the magnet 91 is disposed and cooling water W is circulated through inlet and outlet pipes 12 and 11.
A workpiece 6 is placed on the workpiece holder 18 as is shown in FIGS. 2(a) and 2(b). Since in this case the surface of the target 42 is larger in area than that of the workpiece, the rate of growth of a metallic film on the workpiece is quicker. This is one of the merits of the second example.
Thus, the sputtering devices according to this invention are advantageous in that the sputtering can be achieved at high efficiency even in a gas atmosphere of extremely low pressure, and a fine metallic film is therefore deposited on a workpiece. In addition, the sputtering devices according to this invention provide good cooling, and therefore it is possible to form a metallic film even on materials, such as paper and synthetic resin, which are low in thermal stability.
In the examples described above, the direct current sputtering method is employed; however, it should be noted that the invention is not limited thereto or thereby. That is, the RF sputtering method using a high-frequency electric source can be employed in the examples.
A third example of a sputtering device according to this invention, as shown in FIG. 3, is similar to the first example except that a plurality of small magnets 92 are disposed in the target 4 so that the distribution in thickness of a metallic film deposited on a workpiece 6 is uniform.
In the sputtering device having a cylindrical magnet such as that shown in FIGS. 1(a) and 1(b), only the part of the target 4 where the magnet 9 is provided is the sputtering source. Therefore, the thickness of a metallic film is uneven as is shown in FIG. 4. This has been known through several experiments.
In order to overcome this difficulty accompanying the first example, the single cylindrical magnet 9 shown in FIGS. 1(a) and 1(b) is divided into a plurality of cylindrical magnets 92, that is, a plurality of sputtering sources are formed so that the distribution of metallic atoms emitted by sputtering is uniform throughout the target material.
The third example is similar in construction and operation to the first example shown in FIGS. 1(a) and 1(b). However, the magnets 92 are spaced at suitable intervals along the target material 41. More specifically, the magnets 92 provided at the top and the bottom portion of the target material are spaced at relatively short intervals and at the same time the magnets provided at the middle portion thereof are spaced at relatively long intervals so that the distribution of metallic atoms emitted by sputtering is uniform throughout the target material, that is, the density of the metallic atoms emitted in the electrode space is uniform. Accordingly, the distribution in thickness of a metallic film deposited on a workpiece 6 becomes uniform, too. Therefore, the size (especially the height) of a workpiece 6 to be treated by the third example can be greater than that of a workpiece to be treated by the conventional sputtering devices or the first and second examples described before.
Similarly as in the first and second examples, the sputtering device shown in FIG. 3 is also advantageous in that sputtering can be achieved at high efficiency even in a gas atmosphere of extremely low pressure, and a fine metallic film is deposited on a workpiece.
A fourth example of a sputtering device according to this invention, as shown in FIG. 6, is similar in construction to that shown in FIG. 1(a) except that a magnet 93 provided in the target 4 is moved along the axis of the target 4 so as to obtain uniformity in thickness of a metallic film deposited on a workpiece 6 and also uniformity in consumption of the target 4 (or 41) in the electrode space.
In the sputtering device shown in FIGS. 1(a) and 1(b), the portion of the target 4 where the magnet is provided is the sputtering source. If it is assumed that the electric power applied to the sputtering device is constant, the rate of sputtering of the target 4 is proportional to the strength of the magnetic field H and to the perpendicularity of the magnetic field H with the electric field E (or how close the angle formed by the magnetic and electric fields is to 90°) on the surface of the target. Therefore, the consumption of the target 4 due to the sputtering, as shown in FIG. 7, is concentrated at the central portion of the target where the center of the magnet 9 is positioned, that is, the central portion of the target is decayed. The more the sputtering advances, the more the consumption is increased. Thus, the central portion of the target 4 is consumed sooner than the other portion. Therefore, it is necessary to replace the target 4 when the central portion of the target material has been consumed. Otherwise, the sputtering rate is decreased, which leads to lowering the efficiency of the sputtering device.
Accordingly, the service life of the target 4 is short in this sputtering device. This is considerably uneconomical.
Furthermore, the thickness of a metallic film formed on a workpiece 6 is greater at its portion opposite to the central portion of the target which has been most deeply decayed by sputtering than the other portion (FIG. 4). Therefore, it is impossible to deposit a metallic film uniform in thickness on the workpiece by the use of the sputtering device shown in FIG. 1(a).
The sputtering device shown in FIG. 6 is designed to overcome the above-described difficulty accompanying the sputtering device of FIG. 1(a).
In the sputtering device (FIG. 6), the length of the magnet 93 is shorter than the length L of the target 4, and this magnet 93 is moved vertically, or along the target 4, by means such as a manual operation, a motor-operated mechanism, or a hydraulic mechanism.
In the sputtering device thus described, during sputtering the magnet 93 is moved at least half a reciprocating distance along the target 4 with the progress of the sputtering. Accordingly, as the magnet 93 is moved in this way, the portion of the target 4 where the sputtering is effected most is also moved. As a result, the surface of the target 4 is uniformly consumed, and therefore a metallic film uniform in thickness is deposited on a workpiece 6.
In the sputtering device shown in FIG. 6, the phenomenon that the target is locally sputtered as in the case of the conventional sputtering devices, or the first and second examples of the invention is not observed, that is, the target is uniformly consumed, and accordingly, the target can be effectively and economically used. Moreover, the thickness of a metallic film deposited on a workpiece is uniform.
Thus, with the sputtering device shown in FIG. 6, the deposition of metal film can be achieved economically with good results. This sputtering device is suitable for depositing a metallic film on a relatively long workpiece.
Furthermore, since the magnet 93 is movable as described, that is, the distribution of the magnetic field in the electrode space is controlled, sputtering can be effected at a desired portion of the target, that is, the distribution in thickness of a metallic film on a workpiece can be controlled as desired.
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The sputtering device disclosed herein is based on the fact that the lower the pressure of a gas atmosphere in which glow discharge is effected the smaller the number of chances for metallic atoms emitted from a target or cathode by sputtering to collide with residual molecules between the electrodes is, and the finer the finish of a metallic film formed by depositing the metallic atoms arriving directly to a workpiece is. Also, if the energy of electrons emitted from the target is reduced upon arrival at the anode, the temperature rise inside of the device and especially that of the workpiece can be minimized.
The target and the anode are provided in the form of coaxial cylinders, and a magnet is disposed in the target in such a manner that the direction of the magnetic field orthogonally crosses that of the electric field, so that the electro-magnetic force encloses the electrons in an electrode space to increase the density of electrons therein, whereby sputtering is effectively carried out even in a gas atmosphere of extremely low pressure and direct collision of the electrons with the anode is prevented, thereby minimizing the temperature rise of the work-piece.
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FIELD OF THE INVENTION
[0001] The field of the invention relates to applicators for nasal cannulae of the type defined in the preambles of the independent patent claims.
[0002] The invention relates to the field of nasal cannulae, which are used for pneumatically splinting the respiratory tract.
DISCUSSION OF RELATED ART
[0003] In the CPAP therapy (Continuous Positive Airway Pressure Therapy) a patient is supplied via a nose mask with a continuous positive airway pressure relative to the ambient air pressure. This positive airway pressure, if chosen appropriately, ensures that the upper respiratory tract remains completely opened during the whole night, so that no obstructive respiratory disorders occur. One also talks about pneumatically splinting the respiratory tract. The necessary positive airway pressure depends, inter alia, on the sleep phase and the position of the body of the sleeping person. In order to limit the positive airway pressure, which is perceived as unpleasant, to the necessary amount a therapy apparatus (AutoCPAP) is disclosed in WO 02/083221 A2, which adjusts the positive airway pressure automatically, thereby adapting it to the sleep phase and the position of the body.
[0004] In order to facilitate the breathing, moreover, BiPAP apparatus and multilevel apparatus have been developed. These apparatus have the property to support the patient's breathing by reducing the positive airway pressure as he is exhaling and by increasing the positive airway pressure again as he is inhaling. That is, these apparatus work with at least two pressure levels. Such apparatus are known, for instance, from DE 691 32 030 T2 and WO 02/26283 A2.
[0005] Furthermore, oxygen nasal cannulae for the oxygen treatment are known from the prior art. By means of the oxygen nasal cannula air at an increased oxygen partial pressure (>210 mbar) or pure oxygen is administered into the patient's nose. An oxygen treatment is carried out, for instance, in case of an acute or chronic hypoxemia resulting from a respiratory or cardiovascular disorder (myocardial infarction, shock) or certain intoxications caused, for instance, by carbon monoxide, carbon dioxide, coal gas or smoke.
[0006] The use of oxygen nasal cannulae in an anti-snore apparatus is known from WO 02/062413 A2. In this context oxygen nasal cannulae are designated as nasal cannulae. WO 02/062413 A2 further discloses nasal cannulae having integrated jet pumps, which are illustrated in FIGS. 4 and 5 of 02/062413 A2.
[0007] US 2003/0079749 A1 and WO 2006/072231 A2 describe nasal cannulae whose nose pieces have rounded edges. The air sweeps past these edges, thereby largely avoiding hissing and whistling noises.
[0008] FR 2 827 778 discloses an apparatus which is designated as a monolithic part and resembles the nose part of a nasal cannula. The apparatus serves to support a patient's respiration without or with insufficient spontaneous respiration through the nostrils. The dimensions are adapted to premature infants. Distal, tubular elements project into the nostrils. Foamed discs around the tubular elements serve as a resilient stop. In another embodiment the tubular elements are placed in two dome-shaped sleeves which are connected by a bridge on the side of the sleeves facing away from the nose. Two ducts are supplied with a respirable gas in parallel. A capillary tube serves as a pressure probe. At the beginning of an inspiration phase a supply device receives through the capillary tube a pressure drop and can supply the patient with a continuous or pulse-shaped jet of respirable gas. After an inspiration phase the supply device is instructed by the pressure transmitted through the capillary tube to stop the gas supply. Thus, the patient is able to freely exhale.
SUMMARY OF THE INVENTION
[0009] It is the object of the invention to provide improved applicators for nasal cannulae.
[0010] This object is achieved with the teaching of the independent claims.
[0011] Preferred embodiments of the invention are defined in the dependent claims.
[0012] A valve in a wall of the body of the applicator, with the valve allowing gas only from the ambiance to flow into the body of the applicator, has the surprising advantage that the user is not exposed to the risk of suffocating if the connected compressor is defective.
[0013] A top slipped over the prongs can adapt the outer shape of the prongs in a surprisingly simple fashion to the inner shape of the nostrils of a patient. Thus, merely the small, relatively simply shaped top has a patient-specific shape, and not the large nasal cannula whose shape is relatively complicated. Hence, greater quantities of the nasal cannula and, thus, a reduction of costs are achieved.
[0014] A bridge between the two sealing cones of the top on their side facing the body ( 11 ) prevents a single sealing cone from getting lost. Furthermore, in a surprisingly simple fashion, the sealing cones are prevented from turning out of position on the prongs. Finally, the bridge also prevents the top from unintentionally getting pulled off from the prongs.
[0015] Rim-shaped sealing lips on the side of the sealing cones facing away from the body of the applicator produce a comfortable tight connection with the inner wall of the respective nostril.
[0016] As the sealing cones are partially hollow between an inner part and an outer cone so as to allow a gas flow between the inner part ( 31 , 32 ) and the respective outer cone ( 33 , 34 ) parallel to the inner part ( 31 , 32 ), the additional air resistance in the nostril is kept small by the applicator.
[0017] It is an advantage of the membrane-loaded outlets on the body-sided end of the outer cones that the user does not inhale again the exhaled, used air. Moreover, the choice of the rigidity of the shim-shaped membranes allows an adjustment of the positive airway pressure produced by the applicator, which facilitates the control of the connected compressor.
[0018] The collar on the nose-sided end of the prongs advantageously prevents the top from unintentionally getting pulled off.
[0019] The cover permits a simple mounting of the flexible membrane.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] A preferred embodiment of the invention with reference to the accompanying drawings shall be explained in more detail below. In the drawings:
[0021] FIG. 1 shows a front view of an applicator according to the invention;
[0022] FIG. 2 shows a top view of an applicator according to the invention;
[0023] FIG. 3 shows a rear view of an applicator according to the invention;
[0024] FIG. 4 shows a bottom view of an applicator according to the invention;
[0025] FIG. 5 shows the front view of FIG. 1 without top and cover;
[0026] FIG. 6 shows the bottom view of FIG. 4 without top and cover; and
[0027] FIG. 7 shows the bottom view of FIG. 6 without membranes.
LIST OF REFERENCE NUMBERS
[0000]
1 applicator
11 body
12 top
13 , 14 membrane
15 cover
16 , 17 membrane
18 , 19 prong
20 , 21 tube connection
22 hollow space
23 , 24 sealing cone
25 , 26 , 27 , 28 sealing lip
29 bridge
30 rib
31 , 32 inner cylinder
33 , 34 outer cone
35 , 36 collar
37 oblong hole
38 aperture
39 groove
40 , 41 frusto-conical prolongation
42 braces
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0049] FIG. 1 shows a front view of the applicator 1 according to the invention. The applicator 1 is mainly formed of a body 11 that is connected to a compressor by two tube connections 20 , 21 via a non-illustrated tube loop. The body 11 has two prongs 18 , 19 over which a top 12 has been slipped. The top 12 is substantially comprised of two sealing cones 23 , 24 . Synonyms or equivalents of a compressor are a pump, a compressed air source, a supply device or a blower. In FIG. 1 substantially only the collars 35 , 36 of the prongs 18 , 19 can be seen. The prongs 18 , 19 without the sealing cones 23 , 24 are shown in FIG. 5 .
[0050] The sealing cones according to FIG. 1 are adapted to the inner shape of the nostrils of a user at the top, i.e. on their nose-sided end away from the body. The sealing cones are, in fact, slightly smaller than the openings of the user's nostrils. This small gap is bridged and sealed by sealing lips 25 , 26 , 27 and 28 . The sealing lips 25 , 26 , 27 and 28 themselves have approximately the shape of a circumferential surface of a very flat cone. This means that they extend from the inward top to the outward bottom. As a result of this shape the sealing cones can be easily introduced into the nose and represent a small resistance to prevent the applicator from slipping out of the nose.
[0051] The sealing cones 23 , 24 are connected to each other on their lower end, which is away from the nose and close to the body, by a bridge 29 in order to prevent the sealing cones 23 , 24 from being pulled off from the prongs 18 , 19 too easily and to prevent the sealing cones 23 , 24 from being turned out of position relative to the body 11 and the user's nostrils.
[0052] On the side of the body 11 opposite the prongs 18 , 19 the body 11 is provided with an oblong hole 37 , which is easy to recognize in FIGS. 6 and 7 . The oblong hole 37 is sealed by a cover 15 which forms two valves together with the membranes 16 , 17 (see FIG. 4 ). The cover has a circumferential groove 39 on its outer edge, which engages with the wall of body 11 that limits the oblong hole 37 . Hence, the cover 15 is clamped relative to the wall of body 11 and seals the oblong hole 37 in a gas-tight manner.
[0053] The body 11 encloses a hollow space 22 . Especially the inner surfaces of the body 11 do not have any sharp edges. Rather are all edges rounded off so as to minimize flow noises. As the wall of the body 11 has approximately the same thickness these rounded portions can also be seen on the outside of body 11 .
[0054] FIG. 2 shows a top view of an applicator according to the invention. It can be recognized that the sealing cones 23 , 24 are comprised of outer cones 33 and 34 , inner cylinders 31 and 32 and ribs 30 mechanically connecting the outer cones 33 , 34 to the inner cylinders 31 , 32 . The outer surfaces of the prongs 18 , 19 are approximately cylindrical and define a fit with the inner surfaces of the inner cylinders 31 , 32 .
[0055] In operation respirable gas compressed by a compressor flows from the tube connections 20 , 21 through the hollow space 22 through the prongs 18 , 19 into the nose of a user. Vice versa, exhaled air flows through the sealing cones 23 , 24 , i.e. between the inner cylinders 31 , 32 and the outer cones 33 , 34 past the ribs 30 , through slightly downwardly bent membranes 13 and 14 to the outside. This means that the user practically no longer inhales any exhaled air.
[0056] As shown in FIG. 1 , the outer cones 33 , 34 end slightly above the body 11 , while the inner cylinders 31 , 32 come up to the body 11 . The openings between the inner cylinders 31 , 32 and the outer cones 33 , 34 are sealed by the membranes 13 , 14 . However, if there is a certain positive airway pressure between the inner cylinders 31 , 32 and the outer cones 33 , 34 , as is the case during exhaling, the membranes 13 , 14 are bent slightly downwardly so that exhaled air can escape to the atmosphere. The administered positive airway pressure can be adjusted by means of the hardness of the membranes 13 , 14 and the size of the membranes 13 , 14 together with the size of the body-sided outlets of the sealing cones 23 , 24 . The inner cylinders 31 , 32 have at least one step which presses the membranes 13 , 14 against the outer cones 33 , 34 . In another embodiment the inner cylinders 31 , 32 may also be provided with grooves which fix the vertical positions of the membranes relative to the outer cones 33 , 34 .
[0057] FIG. 3 shows a rear view of an applicator according to the invention.
[0058] FIG. 4 shows a bottom view of an applicator according to the invention. In this view one can recognize the two valves in the cover 15 . The cover 15 has two round cavities each partially closed by a cross. Between the braces 42 of the cross four approximately quadrant-shaped apertures 38 remain in the cover 15 . The apertures 38 are sealed from inside by the flexible membranes 16 , 17 so that air can enter the hollow space 22 from the outside, while it cannot escape from inside out of the hollow space 22 through the apertures 38 to the outside. FIG. 6 shows the same view as FIG. 4 , however, without illustrating the cover 15 , so that the membranes 16 , 17 seem to float in the air. The two valves allow a user to inhale even if no respirable gas is supplied through the tube connections 20 , 21 in the event of a failure of the compressor.
[0059] The two membranes 16 , 17 each have a frusto-conical prolongation 40 and 41 in the center which projects towards the viewer in FIGS. 4 and 6 . The frusto-conical prolongations are connected to the actual membranes by cylindrical sections. The cylindrical sections have a diameter smaller than the largest diameters of the frusto-conical prolongations, so that a groove is defined between each frusto-conical prolongation and the respective membrane. This groove rests in a central hole in the braces 42 of the crosses in the cavities of the cover 15 .
[0060] FIG. 5 shows a view similar to that of FIG. 1 , however, without illustrating the top 12 with the sealing cones 23 , 24 and the cover 15 . That is, the cylindrical prongs 18 , 19 , the collars 35 , 36 as well as the membranes 13 , 14 are easier to recognize. On the bottom side, the frusto-conical prolongations 40 , 41 of the membranes 16 , 17 project out of the oblong hole 37 .
[0061] FIG. 7 shows a view similar to that of FIG. 6 , however, without illustrating the membranes 16 and 17 . In this view, the oblong hole 37 allows a sight through the hollow space 22 to the inside of the rounded junctions between the prongs 18 , 19 and the rest of the body 11 . On the inside the radius of the rounded portion is approximately as large as the inner diameter of the prongs 18 , 19 . One can see in FIG. 5 that the radius of this rounded portion on the outside is approximately half as large as on the inside. That is because the wall thickness in the region of the prongs 18 , 19 is approximately half the size as in the rest of the body 11 .
[0062] In can be recognized in FIGS. 2 , 4 , 6 and 7 that the body is substantially broader than the tube connections 20 , 21 . Apart from the purpose of providing space for the cover 15 and the valves located in the cover 15 this measure also has the purpose of reducing the flow velocity of the gas in the junction region between the prongs 18 , 19 and the body 11 by enlarging the cross-section, thereby reducing flow noises.
[0063] The invention was explained in more detail by means of preferred embodiments above. A person skilled in the art will appreciate, however, that various alterations and modifications may be made without departing from the spirit of the invention. Therefore, the scope of protection will be defined by the following claims and their equivalents.
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The invention relates to an applicator for a nasal cannula, comprising a body ( 11 ) enclosing a hollow space ( 22 ). The applicator further comprises tube connections ( 20, 21 ) for supplying a respirable gas into the hollow space ( 22 ). The applicator further comprises prongs ( 18, 19 ) for administering the respirable gas into the nostrils of a person. A valve ( 15, 16, 17, 38, 42 ) is located in a wall of the body ( 11 ) so that respirable gas can flow from the outside through the valve into the hollow space ( 22 ), but not in the reverse direction. The invention further relates to an applicator having a top of sealing cones ( 23, 24 ), wherein the sealing cones ( 23, 24 ) may be provided with rim-shaped sealing lips on their side facing away from the body ( 11 ), which produce a tight seal with the inner wall of the respective nostril.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. National Stage Application of International Application No. PCT/EP2011/067361 filed Oct. 5, 2011, which designates the United States of America, and claims priority to DE Application No. 10 2010 042 969.4 filed Oct. 26, 2010, the contents of which are hereby incorporated by reference in their entirety.
TECHNICAL FIELD
[0002] The disclosure relates to a piezoelectric component comprising a stack-like actuator body, in which a plurality of piezoelectric elements and internal electrode layers are arranged in an alternating manner in a stacking direction. In this case, the internal electrode layers are each alternately electrically conductively connected to one of two metallizations on an outer face of the stack. The two metallizations are each connected to an electrically conductive electrode structure by an electrically conductive contact element. The piezoelectric component may be embodied, for example, as a piezoelectric actuator in a fuel injection valves for a motor vehicle.
BACKGROUND
[0003] Piezoelectric components of this kind are used, for example, as piezoelectric actuators in fuel injection valves for motor vehicles. It is known that stack-like actuator bodies of this type, also called piezo stacks in the text which follows, tend to develop cracks. In particular, monolithic piezo stacks, in which the internal electrodes do not each extend over the entire cross-sectional area of the piezo stack, exhibit inactive regions in which the piezoelectric elements which are arranged in between are not deflected when a voltage is applied. In contrast, the piezoelectric element is expanded when a voltage is applied in the active region of the piezo stack, in which each piezoelectric layer is arranged between two electrodes. Therefore, during operation and even during polarization, voltages which lead to cracks in the piezoelectric elements can be produced in the boundary region between this active region and the inactive region.
[0004] Cracks of this type can spread over the metallizations on the side faces of the piezo stack during operation. In order to avoid breakdown of the piezo stack, the outer metallizations are reinforced, for example, by metallic structures, such as wire meshes or the like. Said metallic structures are designed, for example, in such a way that they can bridge cracks in the metallization at any desired points and therefore prevent disconnection of individual subregions of the piezo stack from the power supply.
[0005] More recent developments in stack production have, on account of the introduction of predetermined breaking points, led to the piezo stacks breaking at defined points. In this case, for example, porous intermediate layers, which preferably break when the stack is mechanically overloaded, are provided during stack production. On account of a crack of this type, the piezo stack can be, for example, completely separated into two stack elements. Piezo stacks with predetermined breaking points are known, for example, from DE 10 2004 031 402 A1 and DE 10 2004 031 404 A1.
[0006] Known contact-making arrangements, for example with a wire meshing, which can bridge the cracks in a piezo stack which occur in the outer metallization place high demands on the metallic structures used and are accordingly expensive.
SUMMARY
[0007] One embodiment provides a piezoelectric component, comprising a stack-like actuator body, in which a plurality of piezoelectric elements and internal electrode layers are arranged in an alternating manner in a stacking direction, wherein the internal electrode layers are each alternately electrically conductively connected to one of two metallizations on an outer face of the stack, and the metallizations are each connected to an electrically conductive electrode structure by an electrically conductive contact element, wherein the stack-like actuator body has at least one predetermined breaking point, and the metallizations and/or the contact elements have/has a cutout in the region of the at least one predetermined breaking point.
[0008] In a further embodiment, the contact elements, with the exception of the region of the at least one predetermined breaking point, form a fixed connection between the metallizations and the electrode structures.
[0009] In a further embodiment, the contact elements comprise solder or conductive adhesive.
[0010] In a further embodiment, the electrode structure is designed to be expandable at least in the region of the at least one predetermined breaking point.
[0011] In a further embodiment, the electrode structure has a metallic mesh or has a meandering metallic structure at least in parts.
[0012] In a further embodiment, the stack-like actuator body is of monolithic design.
[0013] Other embodiments provide a fuel injection valve for use in a motor vehicle, the fuel injection comprising a piezoelectric component including any of the features disclosed above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Exemplary embodiments will be explained in more detail below based on the schematic drawings, wherein:
[0015] FIG. 1 schematically shows an example piezoelectric component according to a first example embodiment; and
[0016] FIG. 2 shows a piezoelectric component according to a second example embodiment.
DETAILED DESCRIPTION
[0017] Embodiments of the present disclosure provide an improved contact-making arrangement for a piezo stack, which contact-making arrangement avoids the abovementioned problems.
[0018] Some embodiments provide a piezoelectric component comprising a stack-like actuator body, in which a plurality of piezoelectric elements and internal electrode layers are arranged in an alternating manner in a stacking direction. The internal electrode layers are each alternately electrically conductively connected to one of two metallizations on an outer face of the stack. The metallizations are each connected to an electrically conductive electrode structure by an electrically conductive contact element.
[0019] In this case, the stack-like actuator body has at least one predetermined breaking point, and the metallizations and/or the contact elements have/has a cutout in the region of the at least one predetermined breaking point.
[0020] Some embodiments provide a fuel injection valve for a motor vehicle, wherein the valve comprises a piezoelectric actuator as disclosed herein.
[0021] Some embodiments are based on the fact that the expansion of the piezo stack is distributed largely homogeneously over the length of the piezo stack in the interior of the piezo stack when a voltage is applied. However, in the outer region, that is to say on the outer faces with the main contact-making arrangements, the expansion in length is concentrated in the region of the predetermined breaking points by the predetermined breaking points. A crack in the piezo stack at the predetermined breaking point can lead to separation of the metallization. Therefore, the two subregions, which adjoin the predetermined breaking point, of the outer faces of the stack are subject to a comparatively large relative shift in relation to one another in the event of a change in length of the total stack. In contrast, the relative change in length of the outer face of the stack between two predetermined breaking points is comparatively low.
[0022] This permits a fixed connection between the metallization and the electrode structures in the case of the disclosed piezoelectric component, with the exception of the region of the predetermined breaking points. In order to establish a fixed connection of this type, the contact elements may comprise solder or conductive adhesive. Even when there is a largely flat contact-connection between the electrode structures and the metallization outside the region of the predetermined breaking points, this can follow a relatively small change in length. To this end, the entire electrode structure may be expandable or at least flexible.
[0023] However, the electrode structure may be designed to be expandable at least in the region of the predetermined breaking points. This provides the advantage that the electrode structure can also bridge a comparatively large relative change in length in the region of the predetermined breaking point. Therefore, a reliable contact-connection can be ensured over the entire stack length. The electrode structure may be designed to be elastically expandable at least in the region of the predetermined breaking point.
[0024] An expandable electrode structure of this type can be formed, for example, by a metallic mesh or a meandering metallic structure. In this case, the ability to expand can be realized due to the shaping of the electrode structure in combination with an ability of the material to deform.
[0025] The stack-like actuator body of the piezoelectric component may preferably be a monolithically designed piezo stack in which piezoceramic layers and internal electrodes are stacked and sintered to form a block. Making contact with the piezoelectric component may be advantageous for use in piezoelectric stacks which, on account of the design of the internal electrodes, have active and inactive regions. However, in principle, the piezo stack can also be a fully active stack in which the internal electrodes cover the entire cross-sectional area of the stack. There are no inactive regions in fully active piezo stacks of this kind since, when a voltage is applied, voltage is passed through all the piezoceramic layers by virtue of the applied electrodes and therefore said piezoceramic layers are deflected.
[0026] The piezoelectric component 10 illustrated in FIG. 1 , which may be embodied for example as a piezoelectric actuator of a fuel injection valve in a motor vehicle, comprises a stack 11 in which piezoelectric elements 12 are arranged alternately with internal electrode layers 13 a and 13 b in stacks. The stack-like actuator body 11 is sintered to form a monolithic block from the piezoceramic layers 12 with electrode layers 13 a or 13 b applied thereto and porous intermediate layers 17 , which are arranged therebetween, for forming the predetermined breaking points. The internal electrode layers 13 a and 13 b alternately lead to two outer faces of the actuator stack, where they are electrically conductively connected to a metallization 14 a or 14 b.
[0027] An expandable electrode structure 15 is attached to the outer face of the surface metallization 14 a or 14 b by a contact element 16 , wherein the region of the predetermined breaking points 17 of the piezo stack is cutout. The contact element 16 is, for example, conductive adhesive or solder. A fixed connection between the electrode structure 15 and the metallization 14 is formed outside the regions of the predetermined breaking points 17 by said contact element. A separate electrode structure 15 is attached to each of the metallizations 14 a and 14 b.
[0028] The electrode structure 15 comprises a wire mesh which is designed to be expandable at least in the region of the predetermined breaking points. An external electrical voltage can be applied to the piezoelectric component at the electrode structures 15 by means of connection elements. The voltage is applied to the individual piezoceramic layers 12 via the internal electrodes 13 a and 13 b. As a result, the individual piezoceramic layers experience a change in thickness, as a result of which the length of the stack-like actuator body changes. On account of the predetermined breaking points 17 in the actuator body, the change in length at the side faces of the actuator stack 11 takes place substantially in the region of the predetermined breaking points 17 . In contrast, the relative change in length at the outer faces in the regions between the predetermined breaking points 17 is comparatively low. Therefore, a fixed connection between the electrode wire mesh 15 and the metallization 14 a or 14 b can be maintained. The contact element 16 is interrupted only in the region of the predetermined breaking points 17 , and therefore the expandable wire mesh 15 can elastically compensate the movement of the piezo stack in this region.
[0029] FIG. 2 shows a second example embodiment of the piezoelectric component, which may be embodied for example as a piezoelectric actuator of a fuel injection valve in a motor vehicle, with identical components being provided with the same reference symbols as shown in the embodiment of FIG. 1 . The layered body 11 comprising piezoceramic layers 12 and internal electrodes 13 a and 13 b and also the predetermined breaking points 17 is of identical design to the layered body of the first exemplary embodiment from FIG. 1 . However, in contrast to the first exemplary embodiment, the metallization 14 a and 14 b is interrupted in the region of the predetermined breaking points 17 in this case. The metallization 14 a and 14 b usually has an adhesion promoter which firstly ensures adhesion of the surface metallization on the ceramic stack 11 and secondly makes it possible for solder or conductive adhesive to adhere to the metallization layer. The cutout in the surface metallization 14 a and 14 b in the region of the predetermined breaking point 17 has the result that solder or conductive adhesive which is applied over the surface or continuously in said region does not adhere to the ceramic layer element. There is therefore a cutout between the electrode 15 and the layered body in the region of the predetermined breaking points 17 .
[0030] An expandable electrode structure 15 , for example a wire mesh or a meandering metallic structure, can maintain its ability to expand even when solder or conductive adhesive is applied to it.
[0031] The ability to expand is restricted only when the contact-making arrangement is fixedly connected to the surface metallization of a ceramic body 11 by the solder or the conductive adhesive. In this way, the ability of the electrode 15 to expand in the region of the predetermined breaking points 17 can be utilized, and the interruption in the surface metallization 14 a or 14 b can therefore be bridged, in the case of the design variant illustrated in FIG. 2 too.
[0032] The disclosed piezoelectric component therefore has a reliable contact-making arrangement for piezoelectric layer elements with a lower stiffness than conventional contact-making arrangements. Since the ability of the contact-making arrangement or the wire mesh electrode or meandering structure to expand can be limited to regions of the predetermined breaking points, substantially more simple and more cost-effective electrode structures are possible in this case.
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A piezoelectric component, e.g., for use as an actuator of a fuel injection valve in a motor vehicle, may include a stack-shaped actuator body including a plurality of piezoelectric elements and inner electrode layers arranged in an alternating manner in a stacking direction, each inner electrode layer being connected alternately to one of two metalizations on an outer face of the stack in an electrically conductive manner. Each metalization is connected to an electrically conductive electrode structure via an electrically conductive contacting element (e.g., adhesive or solder). The stack-shaped actuator body has at least one predetermined breaking point, and the metalizations and/or the contacting elements have a recess in the region of the at least one predetermined breaking point.
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CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims under 35 U.S.C. §119(a) the benefit of Taiwanese Application No. 102128808, filed Aug. 12, 2013, the entire contents of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to semiconductor packages and fabrication methods thereof, and more particularly, to a semiconductor package having wafer-level circuits and a fabrication method thereof.
2. Description of Related Art
Along with the rapid development of electronic industries, electronic products are developed toward multi-function and high electrical performance. Accordingly, there have been developed various types of flip-chip packaging modules such as chip scale packages (CSPs), direct chip attached (DCA) packages and multi-chip module (MCM), and 3D IC chip stacking technologies.
FIG. 1A is a schematic cross-sectional view of a conventional semiconductor package 1 . Referring to FIG. 1A , the semiconductor package 1 has a packaging substrate 14 having a plurality of bonding pads 140 having a large pitch, a through silicon interposer (TSI) 10 disposed on the packaging substrate 14 , and a semiconductor chip 12 disposed on the through silicon interposer 10 and having a plurality of electrode pads 120 having a small pitch. The through silicon interposer 10 has a plurality of through silicon vias (TSVs) 100 formed therein and a redistribution layer (RDL) structure 101 formed on the TSVs 100 . The RDL structure 101 is electrically connected to the bonding pads 140 of the packaging substrate 14 through a plurality of conductive elements 18 . An underfill 13 is formed between the through silicon interposer 10 and the packaging substrate 14 for encapsulating the conductive elements 18 . The electrode pads 120 of the semiconductor chip 120 are electrically connected to the TSVs 100 of the through silicon interposer 10 through a plurality of solder bumps 121 . Further, an underfill 13 is formed between the through silicon interposer 10 and the semiconductor chip 120 for encapsulating the solder bumps 121 .
If the semiconductor chip 12 is directly disposed on the packaging substrate 14 , joints formed between the solder bumps 121 of the semiconductor chip 12 and the bonding pads 140 of the packaging substrate 14 can be adversely affected by a big CTE (Coefficient of Thermal Expansion) mismatch between the semiconductor chip 12 and the packaging substrate 14 , thus easily resulting in delamination of the solder bumps 121 from the packaging substrate 14 . Further, the CTE mismatch between the semiconductor chip 12 and the packaging substrate 14 induces more thermal stresses and leads to more serious warpages, thereby reducing the reliability of electrical connection between the semiconductor chip 12 and the packaging substrate 14 and even resulting in failure of a reliability test.
Therefore, the through silicon interposer 10 made of a semiconductor material close to the semiconductor chip 12 is provided so as to effectively overcome the above-described drawbacks.
However, to form the TSVs 100 of the through silicon interposer 10 , a plurality of through holes need to be formed in the through silicon interposer 10 and filled with a metal material, which incurs a high cost. For example, for a 12-inch wafer, the TSV cost occupies about 40% to 50% of the total cost for fabricating the through silicon interposer 10 . Consequently, the cost of the final product is increased.
Further, the fabrication of the through silicon interposer 10 is quite complicated, thus resulting in a low yield of the semiconductor package 1 .
To overcome the above-described drawbacks, a semiconductor package 1 ′ without a through silicon interposer, as shown in FIG. 1B , is proposed. Referring to FIG. 1B , a plurality of semiconductor chips 12 are disposed on a circuit portion 11 on a carrier (not shown) through a plurality of solder bumps 121 . Then, an encapsulant 16 is formed on the circuit portion 11 for encapsulating the semiconductor chips 12 so as to protect the semiconductor chips 12 and increase the rigidity of the semiconductor package 1 ′. Thereafter, the carrier (not shown) on the lower side of the circuit portion 11 is removed and an insulating layer 17 is formed on the lower side of the circuit portion 11 . The circuit portion 11 is partially exposed from the insulating layer 17 so as for a plurality of conductive elements 18 such as solder balls to be formed thereon.
However, since the gap between the semiconductor chips 12 is very small, when the carrier on the lower side of the circuit portion 11 is removed, stresses induced by a CTE mismatch between the semiconductor chips 12 , inter-metal dielectric (IMD) layers of the circuit portion 11 and the encapsulant 16 can easily cause cracking of the IMD layers of the circuit portion 11 and even cause cracking of the solder bumps 121 , for example, a crack k of FIG. 1B .
Therefore, there is a need to provide a semiconductor package and a fabrication method thereof so as to overcome the above-described drawbacks.
SUMMARY OF THE INVENTION
In view of the above-described drawbacks, the present invention provides a semiconductor package, which comprises: a circuit portion having opposite first and second sides; a plurality of semiconductor elements disposed on the first side of the circuit portion; a lamination member disposed on the semiconductor elements; and an insulating layer formed on the first side of the circuit portion for encapsulating the semiconductor elements.
In the above-described package, the insulating layer can further encapsulate the lamination member. Furthermore, the lamination member can be exposed from a surface of the insulating layer.
In the above-described package, the insulating layer can be flush on sides with the lamination member.
The above-described package can further comprise an adhesive layer formed between the semiconductor elements and the lamination member. The adhesive layer can further be formed between the insulating layer and the lamination member. The adhesive layer can be made of a die attach film (DAF) or a thermal interface material (TIM).
In the above-described package, the insulating layer can further be formed between the lamination member and the semiconductor elements.
The above-described package can further comprise a plurality of conductive elements formed on the second side of the circuit portion.
The present invention further provides a fabrication method of a semiconductor package, which comprises the steps of: providing a semiconductor structure comprising a carrier, a circuit portion formed on the carrier and a plurality of semiconductor elements disposed on the circuit portion; disposing a lamination member on the semiconductor elements; forming an insulating layer on the circuit portion for encapsulating the semiconductor elements; and removing the carrier.
In the above-described method, the insulating layer can further encapsulate the lamination member. After forming the insulating layer, the method can further comprise exposing the lamination member from a surface of the insulating layer.
In the above-described method, the lamination member can be disposed on the semiconductor elements through an adhesive layer. The adhesive layer can be made of a die attach film (DAF) or a thermal interface material (TIM).
In the above-described method, the carrier can be a silicon-containing substrate.
After the carrier is removed, the above-described method can further comprise exposing the circuit portion so as to form a plurality of conductive elements on the circuit portion.
The present invention provides another fabrication method of a semiconductor package, which comprises the steps of: providing a semiconductor structure comprising a carrier, a circuit portion formed on the carrier and a plurality of semiconductor elements disposed on the circuit portion; forming an insulating layer on the circuit portion for encapsulating the semiconductor elements; disposing a lamination member on the semiconductor elements and the insulating layer; and removing the carrier.
In the above-described method, the lamination member can be disposed on the semiconductor elements and the insulating layer through an adhesive layer. The adhesive layer can be made of a die attach film (DAF) or a thermal interface material (TIM).
In the above-described method, the carrier can be a silicon-containing substrate.
After the carrier is removed, the above-described method can further comprise exposing the circuit portion so as to form a plurality of conductive elements on the circuit portion.
The present invention still provides another fabrication method of a semiconductor package, which comprises the steps of: providing a semiconductor structure comprising a carrier, a circuit portion formed on the carrier and a plurality of semiconductor elements disposed on the circuit portion; providing a lamination member having an insulating layer and disposing the lamination member on the circuit portion through the insulating layer, wherein the insulating layer encapsulates the semiconductor elements; and removing the carrier.
In the above-described method, the insulating layer can further be formed between the lamination member and the semiconductor elements.
In the above-described method, the carrier can be a silicon-containing substrate.
After the carrier is removed, the above-described method can further comprise exposing the circuit portion so as to form a plurality of conductive elements on the circuit portion.
In the above-described package and methods, an underfill can further be formed between the circuit portion and the semiconductor elements.
In the above-described package and methods, the insulating layer can further be formed between the circuit portion and the semiconductor elements.
In the above-described package and methods, the lamination member can be a dummy die.
According to the present invention, a lamination member is provided to increase the strength between adjacent semiconductor elements. Therefore, the present invention overcomes the conventional cracking problem caused by a CTE mismatch between the semiconductor elements and the insulating layer when the carrier is removed.
BRIEF DESCRIPTION OF DRAWINGS
FIGS. 1A and 1B are schematic cross-sectional views of conventional semiconductor packages;
FIGS. 2A to 2E are schematic cross-sectional views showing a fabrication method of a semiconductor package according to a first embodiment of the present invention, wherein FIG. 2E ′ shows another embodiment of FIG. 2E ;
FIGS. 3A to 3D are schematic cross-sectional views showing a fabrication method of a semiconductor package according to a second embodiment the present invention, wherein FIG. 3D ′ shows another embodiment of FIG. 3D ; and
FIGS. 4A to 4D are schematic cross-sectional views showing a fabrication method of a semiconductor package according to a third embodiment the present invention, wherein FIG. 4D ′ shows another embodiment of FIG. 4D .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The following illustrative embodiments are provided to illustrate the disclosure of the present invention, these and other advantages and effects can be apparent to those in the art after reading this specification.
It should be noted that all the drawings are not intended to limit the present invention. Various modifications and variations can be made without departing from the spirit of the present invention. Further, terms such as “first”, “second”, “on”, “a” etc. are merely for illustrative purposes and should not be construed to limit the scope of the present invention.
FIGS. 2A to 2E are schematic cross-sectional views showing a fabrication method of a semiconductor package 2 according to a first embodiment of the present invention.
Referring to FIG. 2A , a semiconductor structure 2 a is provided, which has a carrier 20 , a circuit portion 21 formed on the carrier 20 , a plurality of semiconductor elements 22 disposed on the circuit portion 21 , and an underfill 23 formed between the circuit portion 21 and the semiconductor elements 22 .
In the present embodiment, the carrier 20 is a silicon-containing substrate.
The circuit portion 21 has a plurality of dielectric layers 210 and a plurality of circuit layers 211 alternately stacked on one another. Further, the circuit portion 21 has a first side 21 a on which the semiconductor elements 22 are disposed and a second side 21 b opposite to the first side 21 a and bonded to the carrier 20 .
Each of the semiconductor elements 22 is flip-chip bonded to the circuit layers 211 of the circuit portion 21 through a plurality of conductive bumps 221 , and the underfill 23 encapsulates the conductive bumps 221 .
The circuit layers 211 are wafer-level circuits instead of packaging-substrate-level circuits. Currently, packaging substrates have a minimum line width and pitch of 12 um, while semiconductor processes can provide a line width and pitch below 3 um.
Referring to FIG. 2B , an adhesive layer 24 is formed on the semiconductor elements 22 . In the present embodiment, the adhesive layer 24 is made of a die attach film (DAF) or a thermal interface material (TIM) such as a thermal adhesive.
Referring to FIG. 2C , a lamination member 25 is disposed on the adhesive layer 24 to increase the strength between the semiconductor elements 22 .
In the present embodiment, the lamination member 25 is a dummy die singulated from a wafer.
In another embodiment, the adhesive layer 24 is formed on the lamination member 25 first and then the lamination member 25 having the adhesive layer 24 is disposed on the semiconductor elements 22 through the adhesive layer 24 .
Referring to FIG. 2D , an insulating layer 26 is formed on the first side 21 a of the circuit portion 21 for encapsulating the semiconductor elements 22 .
In the present embodiment, the lamination member 25 is partially encapsulated by the insulating layer 26 and exposed from a surface of the insulating layer 26 . In another embodiment, the lamination member 25 is entirely encapsulated by the insulating layer 26 and not exposed from the insulating layer 26 .
The insulating layer 26 can be an encapsulant, a lamination film or a coating layer.
Referring to FIG. 2E , the carrier 20 is removed to expose the second side 21 b of the circuit portion 21 and a plurality of conductive elements 28 are formed on the second side 21 b of the circuit portion 21 . Thereafter, a singulation process is performed along cutting paths S of FIG. 2D to obtain a plurality of semiconductor packages 2 .
In the present embodiment, a plurality of conductive pads 212 electrically connected to the circuit layers 211 are formed on the second side 21 b of the circuit portion 21 first and then an insulating layer 27 is formed on the second side 21 b of the circuit portion 21 . The insulating layer 27 has a plurality of openings 270 exposing the conductive pads 212 such that the conductive elements 28 such as solder balls are formed on the exposed conductive pads 212 .
In another embodiment, the singulation process can be performed before formation of the conductive pads 212 , the insulating layer 27 and the conductive elements 28 .
In another embodiment, the underfill 23 can be omitted. Instead, the insulating layer 26 is formed between the circuit portion 21 and the semiconductor elements 22 for encapsulating the conductive bumps 221 , as shown in FIG. 2E ′.
FIGS. 3A to 3D are schematic cross-sectional views showing a fabrication method of a semiconductor package 3 according to a second embodiment of the present invention. Different from the first embodiment, the present embodiment forms the insulating layer before disposing the lamination member, which is detailed as follows.
Referring to FIG. 3A , a semiconductor structure 2 a of FIG. 2A is provided.
Referring to FIG. 3B , an insulating layer 36 is formed on the first side 21 a of the circuit portion 21 for encapsulating the semiconductor elements 22 . The semiconductor elements 22 are exposed from a surface of the insulating layer 36 .
Referring to FIG. 3C , a lamination member 35 is disposed on the semiconductor elements 22 and the insulating layer 36 .
In the present embodiment, the lamination member 35 is disposed on the semiconductor elements 22 and the insulating layer 36 through an adhesive layer 34 .
The lamination member 35 is a non-singulated wafer-type dummy die.
Referring to FIG. 3D , the carrier 20 is removed to expose the second side 21 b of the circuit portion 21 and a plurality of conductive elements 28 are formed on the second side 21 b of the circuit portion 21 . Thereafter, a singulation process is performed along cutting paths S of FIG. 3C to obtain a plurality of semiconductor packages 3 . Side surface 36 a of the insulating layer 36 are flush with side surfaces 35 a of the lamination member 35 .
In another embodiment, referring to FIG. 3D ′, after forming the conductive elements 28 and before performing the simulation process, the lamination member 35 is thinned to form a lamination member 35 ′ having a reduced thickness.
FIGS. 4A to 4D are schematic cross-sectional views showing a fabrication method of a semiconductor package 4 according to a third embodiment of the present invention. The present embodiment differs from the second embodiment in the bonding of the lamination member to the semiconductor elements, which is detailed as follows.
Referring to FIG. 4A , a semiconductor structure 2 a of FIG. 2A is provided.
Referring to FIG. 4B , a lamination member 45 having an insulating layer 46 is provided. The lamination member 45 is a non-singulated wafer-type dummy die.
Referring to FIG. 4C , the lamination member 45 is disposed on the first side 21 a of the circuit portion 21 through the insulating layer 46 . The insulating layer 46 encapsulates the semiconductor elements 22 .
In the present embodiment, the insulating layer 46 is formed between the lamination member 45 and the semiconductor elements 22 for bonding the lamination member 45 to the semiconductor elements 22 .
Referring to FIG. 4D , the carrier 20 is removed to expose the second side 21 b of the circuit portion 21 and a plurality of conductive elements 28 are formed on the second side 21 b of the circuit portion 21 . Thereafter, a singulation process is performed along cutting paths S of FIG. 4C to obtain a plurality of semiconductor packages 4 . Side surfaces 46 a of the insulating layer 46 are flush with side surfaces 45 a of the lamination member 45 .
In another embodiment, referring to FIG. 4D ′, after forming the conductive elements 28 and before performing the singulation process, the lamination member 45 is thinned to form a lamination member 45 ′ having a reduced thickness.
According to the present invention, a lamination member 25 , 35 , 35 ′, 45 , 45 ′ is bonded to two adjacent semiconductor elements 22 so as to increase the strength between the adjacent semiconductor elements 22 . Therefore, the present invention avoids cracking of the conductive bumps 221 and the dielectric layers 210 of the circuit portion 21 caused by a CTE mismatch between the semiconductor elements 22 and the insulating layer 26 , 36 , 46 when the carrier 20 is removed.
The present invention further provides a semiconductor package 2 , 2 ′, 3 , 3 ′, 4 , 4 ′, which has: a circuit portion 21 having opposite first and second sides 21 a , 21 b ; a plurality of semiconductor elements 22 disposed on the first side 21 a of the circuit portion 21 ; a lamination member 25 , 35 , 35 ′, 45 , 45 ′ disposed on the semiconductor elements 22 ; and an insulating layer 26 , 36 , 46 formed on the first side 21 a of the circuit portion 21 for encapsulating the semiconductor elements 22 .
The lamination member 25 , 35 , 35 ′, 45 , 45 ′ can be a dummy die.
In an embodiment, the insulating layer 26 further encapsulates the lamination member 25 , and the lamination member 25 is exposed from a surface of the insulating layer 26 .
Preferably, the semiconductor package 2 further has an underfill 23 formed between the first side 21 a of the circuit portion 21 and the semiconductor elements 22 . In another embodiment, the insulating layer 26 is filled between the first side 21 a of the circuit portion 21 and the semiconductor elements 22 .
In an embodiment, the semiconductor package 2 , 2 ′, 3 , 3 ′ further has an adhesive layer 24 , 34 formed between the semiconductor elements 22 and the lamination member 25 , 35 , 35 ′. The adhesive layer 24 , 34 can be made of a die attach film (DAF) or a thermal interface material (TIM). In an embodiment, the adhesive layer 34 is further formed between the insulating layer 36 and the lamination member 35 , 35 ′.
In an embodiment, side surfaces 36 a , 46 a of the insulating layer 36 , 46 are flush with side surfaces 35 a , 45 a of the lamination member 35 , 45 .
In an embodiment, the insulating layer 46 is further formed between the lamination member 45 , 45 ′ and the semiconductor elements 22 .
In an embodiment, the semiconductor package 2 , 2 ′, 3 , 3 ′, 4 , 4 ′ further has a plurality of conductive elements 28 formed on the second side 21 b of the circuit portion 21 .
According to the present invention, a lamination member is bonded to two adjacent semiconductor elements to increase the strength between the adjacent semiconductor elements, thereby avoiding cracking of the conductive bumps of the semiconductor elements.
The above-described descriptions of the detailed embodiments are only to illustrate the preferred implementation according to the present invention, and it is not to limit the scope of the present invention. Accordingly, all modifications and variations completed by those with ordinary skill in the art should fall within the scope of present invention defined by the appended claims.
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A fabrication method of a semiconductor package is disclosed, which includes the steps of: providing a semiconductor structure having a carrier, a circuit portion formed on the carrier and a plurality of semiconductor elements disposed on the circuit portion; disposing a lamination member on the semiconductor elements; forming an insulating layer on the circuit portion for encapsulating the semiconductor elements; and removing the carrier. The lamination member increases the strength between adjacent semiconductor elements so as to overcome the conventional cracking problem caused by a CTE mismatch between the semiconductor elements and the insulating layer when the carrier is removed.
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FIELD OF INVENTION
[0001] This invention relates to a method for fabricating large scaffolds in a variety of shapes with an organized pore structure. The pore structure is organized such that pores are generally aligned perpendicular to the edges of the scaffold, regardless of the particular macroscopic scaffold shape.
BACKGROUND OF THE INVENTION
[0002] Implanting a scaffold to regenerate lost or damaged tissue, requires the use of a scaffold that supports adequate cell migration into and around the scaffold, short-term support of these cells following implantation with an adequate supply of oxygen and nutrients and long-term angiogenesis and remodeling of the scaffold (degradation of the scaffold and remodeling of the vasculature and tissue architecture). These functions should be supported for new stroma and tissue formation.
[0003] Scaffolds are prefabricated supports, which may be seeded with cells. While cells can easily adsorb into the outermost portions of the scaffold, cell distributions may not be uniform throughout the scaffold due to random motility and limitations in the diffusion of nutrients. This in turn may lead to uneven and distorted regeneration of tissue, which, if allowed to persist, may create other pathologies. Even if cells are homogenously distributed throughout a large-scale scaffold, there is a need for a vascular supply to nourish the cells in the interior of the scaffold, since these cells are positioned in a location within the scaffold, which is not readily accessible to the surrounding vasculature and are therefore deprived of nutrients and oxygen necessary for their long term viability. Cell survival necessitates it being within the diffusion distance of a capillary, for the formation of a concentration gradient facilitating an exchange whereby the cell can receive an adequate concentration of oxygen and nutrients. While a vascular supply can grow into an implanted scaffold from surrounding vascularized tissue, the angiogenic process takes time, which may result in cell death in the scaffolding interior, prior to adequate vascularization.
[0004] One of the limitations to date in successful tissue engineering is a lack of an appropriate material and architecture whereby complex tissues may be assembled, in particular providing the ability of appropriate cells to align themselves along desired characteristic dimension to form a functioning tissue. Thus scaffolds, which can provide a size/scale large enough to be applicable for use in the regeneration of breast or of other organs are lacking.
[0005] While, collagen-based scaffolds fabricated via lyophilization (where a suspension of collagen and an acid, is frozen in a pan-shaped, or tubular mold and sublimated to produce sheets (1-3 mm thick) of porous scaffold), the macroscopic shapes obtained by these methods (i.e., small tubes or thin sheets) are familiar. To date, no method producing porous scaffolds with significantly larger characteristic lengths or scaffolds with organized pore structures that influence cell migration as well as nutrient transport into the scaffold have been introduced.
SUMMARY OF THE INVENTION
[0006] In one embodiment, the invention provides a solid, porous scaffold for implantation, comprising an organic polymer, having a width of at least 3.5 mm in at least one direction, and pores oriented perpendicular to an edge of said scaffold. In one embodiment, the scaffold comprises pores situated closer to a surface of said scaffold having a diameter, which is greater than pores situated further from said surface
[0007] In one embodiment, this invention provides a process for preparing a solid, porous, biocompatible scaffold having a width of at least 3.5 mm in at least one direction, and pores oriented perpendicular to an edge of said scaffold, the process comprising the steps of:
a) applying a polymeric mixture to a mold comprised of a conductive material, wherein said mold has at least 2 components b) immersing the suspension-filled mold in (a) in a super-cooled refrigerant held at a constant temperature, for a period of time until said suspension is solidified, whereby ice crystals are formed in said solidified suspension, said crystals being oriented perpendicular to an edge of said scaffold; c) exposing a portion of said solidified suspension to conditions which enable sublimation in said portion, whereby pores are formed which are perpendicular to an edge of said scaffold; and d) removing the remaining components of said mold to expose said solid porous scaffold.
[0012] In another embodiment, this invention provides a scaffold produced according to the processes of the invention.
[0013] In one embodiment, the invention provide a method of organ or tissue engineering in a subject, comprising the step of implanting a scaffold of the inevntion, including in one embodiment, in application to wound healing.
[0014] In one embodiment, the invention provides a method of organ or tissue repair or regeneration in a subject, comprising the step of implanting a scaffold. of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The invention is directed to solid gradient scaffolds, methods of producing the same, and therapeutic applications arising from their utilization.
[0016] Scaffolds are in one embodiment, porous materials used for a variety of tissue engineering applications; one major application of porous scaffolds is as templates that induce regeneration of lost or damaged tissue. In order to treat larger tissues and organs (characteristic length scale>1 mm), it is necessary to develop technologies able to produce scaffolds with significantly larger characteristic lengths, an organized pore structure, and in a variety of macroscopic shapes to suit each implant site.
[0017] In one embodiment, the term “porous” refers to a matrix that comprises holes or voids, rendering the material permeable In another embodiment, the scaffold is non-uniformly porous. In one embodiment, non-uniformly porous scaffolds allow for permeability at some regions, and not others, within the scaffold, or in another embodiment, the extent of permeability differs within the scaffold.
[0018] In one embodiment, this invention provides a solid, porous scaffold for implantation, comprising an organic polymer, having a width of at least 3.5 mm in at least one direction, and pores oriented perpendicular to an edge of the scaffold.
[0019] In one embodiment, the term “scaffold” or “scaffolds” refers to three-dimensional structures that assist in the tissue regeneration process by providing a site for cells to attach, proliferate, differentiate and secrete an extra-cellular matrix, eventually leading to tissue formation. In one embodiment, a scaffold provides a support for the repair, regeneration or generation of a tissue or organ.
[0020] In one embodiment, the scaffold comprises a biocompatible material, which, in another embodiment may comprise carbohydrate, or in another embodiment, proteins or specific amino acids, or in another embodiment, a biocompatible polymer or monomer as described herein, or in another embodiment, a combination thereof.
[0021] In one embodiment, the scaffold comprises at least one polymer, which is a natural polymer, or in another embodiment an organic polymer, or in another embodiment, an extracellular matrix protein, or in another embodiment an analogue thereof, or in another embodiment, a combination thereof.
[0022] In one embodiment, the polymer is a copolymer. In another embodiment, the polymer is a homo- or, in another embodiment heteropolymer. In another embodiment, the polymer of this invention are natural polymer. In another embodiment, the polymer is a free radical random copolymer, or, in another embodiment, a graft copolymer. In one embodiment, the polymer may comprise proteins, peptides or nucleic acids.
[0023] In one embodiment, a graft copolymer of two different extracellular matrix components is formed, such as for example a type I collagen and GAG. The final ratio of collagen/GAG may be equal, in another embodiment, to any combination between 85/15 to 100/0 w/w by methods well known in the art (Yannas, et al. PNAS 1989, 86:933)). According to this aspect of the invention, and in one embodiment, a length of the polymer is then exposed to a concentration gradient of a collagenase, for a period of time, wherein time, in another embodiment, is varied, which may, in another embodiment, provide for greater digestion of for example collagen, in some sections of the scaffold thus exposed. In one embodiment, digestion is a function of enzyme concentration, or in another embodiment, exposure time to a given concentration, or in another embodiment, a combination thereof.
[0024] For example, and in one embodiment, the scaffold is comprised of a graft copolymer of a type I collagen and a GAG, whose ratio is controlled by adjusting the mass of the macromolecules mixed to form the copolymer.
[0025] In another embodiment, the polymer may comprise a biopolymer such as, for example, collagen. In another embodiment, the polymer may comprise a biocompatible polymer such as polyesters of [alpha]-hydroxycarboxylic acids, such as poly(L-lactide) (PLLA) and polyglycolide (PGA); polymer disclosed in U.S. Pat. No. 6,333,029 or 6,355,699; or any bioresorbable and biocompatible polymer, co-polymer or mixture of polymer or co-polymer known in the art, or hereinafter discovered, which perform or function substantially similarly.
[0026] In one embodiment, the biodegradable polymer comprise functional groups such as esters, anhydrides, orthoesters, and amides. In another embodiment, the polymer biodegrades rapidly such as for example in one embodiment poly[lactide-co-glycolide], polyanhydrides, and polyorthoesters. In one embodiment, bioerodible polymers include polylactides, polyglycolides, and copolymers thereof, poly(ethylene terephthalate), poly(butyric acid), poly(valeric acid), poly(lactide-co-caprolactone), poly(lactide-co-glycolide), polyanhydrides, polyphosphazenes, poly(.epsilon.-caprolactone), poly(dioxanone), poly(hydroxybutyrate), poly(hydroxyvalerate), polyorthoesters, blends, and copolymers thereof. Examples of biodegradable and biocompatible polymers of acrylic and methacrylic acids or esters include poly(methyl methacrylate), poly(ethyl methacrylate), poly(butyl methacrylate), poly(isobutyl methacrylate), poly(hexyl methacrylate), poly(isodecyl methacrylate), poly(lauryl methacrylate), poly(phenyl methacrylate), poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutyl acrylate), poly(octadecyl acrylate), etc. Other polymers which can be used in the present invention include polyalkylenes such as polyethylene and polypropylene; polyarylalkylenes such as polystyrene; poly(alkylene glycols) such as poly(ethylene glycol); poly(alkylene oxides) such as poly(ethylene oxide); and poly(alkylene terephthalates) such as poly(ethylene terephthalate). Additionally, polyvinyl polymers can be used which include polyvinyl alcohols, polyvinyl ethers, polyvinyl esters, and polyvinyl halides. Exemplary polyvinyl polymers include poly(vinyl acetate), polyvinyl phenol, and polyvinylpyrrolidone. It is to be understood that any combination of polymers as described herein may be used in the scaffolds and methods of this invention and represent an embodiment thereof.
[0027] In another embodiment, the polymers comprise in one embodiment extracellular matrix (ECM) component. In another embodiment, the ECM component is purified from tissue, by means well known in the art. For example, if collagen is desired, in one embodiment, the naturally occurring extracellular matrix can be treated to remove substantially all materials other than collagen. The purification may be carried out to substantially remove, or in another embodiment, enrich for glycoproteins, or in another embodiment glycosaminoglycans, or in another embodiment proteoglycans, or in another embodiment lipids, or in another embodiment non-collagenous proteins or in another embodiment nucleic acid (DNA or RNA), by methods known to one skilled in the art.
[0028] In one embodiment, the polymer may comprise Type I collagen, Type II collagen, Type IV collagen, gelatin, agarose, cell-contracted collagen containing proteoglycans, glycosaminoglycans or glycoproteins, fibronectin, laminin, elastin, fibrin, synthetic polymeric fibers made of poly-acids such as polylactic, polyglycolic or polyamino acids, polycaprolactones, polyamino acids, polypeptide gel, copolymers thereof and/or combinations thereof.
[0029] In one embodiment, the polymers may comprise a functional group, which enables linkage formation with other molecules of interest, some examples of which are provided further hereinbelow. In one embodiment, the functional group is one, which is suitable for hydrogen bonding (e.g., hydroxyl groups, amino groups, ether linkages, carboxylic acids and esters, and the like).
[0030] In another embodiment, functional groups may comprise an organic acid group. In one embodiment, the term “organic acid group” is meant to include any groupings which contain an organic acidic ionizable hydrogen, such as carboxylic and sulfonic acid groups. The expression “organic acid functional groups” is meant to include in one embodiment, any group that function in a similar manner to organic acid groups under specific reaction conditions, for instance metal salts of such acid groups, such as, for example alkali metal salts like lithium, sodium and potassium salts, or alkaline earth metal salts like calcium or magnesium salts, or quaternary amine salts of such acid groups, such as, for example quaternary ammonium salts.
[0031] In one embodiment, functional groups may comprise acid-hydrolyzable bonds including ortho-ester or amide groups. In another embodiment, functional groups may comprise base-hydrolyzable bonds including alpha-ester or anhydride groups. In another embodiment, functional groups may comprise both acid- or base-hydrolyzable bonds including carbonate, ester, or iminocarbonate groups. In another embodiment, functional groups may comprise labile bonds, which are known in the art and can be readily employed in the methods/processes and scaffolds described herein (see, e.g. Peterson et al., Biochem. Biophys. Res. Comm. 200(3): 1586-159 (1994) 1 and Freel et al., J. Med. Chem. 43: 4319-4327 (2000)).
[0032] In another embodiment, the scaffold further comprises a pH-modifying compound. In one embodiment, the term “pH-modifying” refers to an ability of the compound to change the pH of an aqueous environment when the compound is placed in or dissolved in that environment. The pH-modifying compound, in another embodiment, is capable of accelerating the hydrolysis of the hydrolyzable bonds in the polymer upon exposure of the polymer to moisture and/or heat. In one embodiment, the pH-modifying compound is substantially water-insoluble. Suitable substantially water-insoluble pH-modifying compounds may include substantially water-insoluble acids and bases. Inorganic and organic acids or bases may be used, in other embodiments.
[0033] In one embodiment, as described herein, other molecules may be incorporated within the scaffold, which may, in another embodiment, be attached via a functional group, as herein described. In another embodiment, the molecule is conjugated directly to the scaffold.
[0034] In one embodiment, the extracellular matrix proteins comprise a collagen, a glycosaminoglycan, or a combination thereof. In another embodiment, the polymers of this invention may comprise extracellular matrix components, such as hyaluronic acid and/or its salts, such as sodium hyaluronate; glycosaminoglycans such as dermatan sulfate, heparan sulfate, chondroiton sulfate and/or keratan sulfate; mucinous glycoproteins (e.g., lubricin), vitronectin, tribonectins, surface-active phospholipids, rooster comb hyaluronate. In some embodiments, the extracellular matrix components may be obtained from commercial sources, such as ARTHREASE™ high molecular weight sodium hyaluronate; SYNVISC® Hylan G-F 20; HYLAGAN® sodium hyaluronate; HEALON® sodium hyaluronate and SIGMA® chondroitin 6-sulfate.
[0035] In another embodiment, one or more biomolecules may be incorporated in the scaffold. The biomolecules may comprise, in other embodiments, drugs, hormones, antibiotics, antimicrobial substances, dyes, radioactive substances, fluorescent substances, silicone elastomers, acetal, polyurethanes, radiopaque filaments or substances, anti-bacterial substances, chemicals or agents, including any combinations thereof. The substances may be used to enhance treatment effects, reduce the potential for implantable article erosion or rejection by the body, enhance visualization, indicate proper orientation, resist infection, promote healing, increase softness or any other desirable effect.
[0036] In one embodiment, the scaffold varies in terms of its polymer concentration, or concentration of and component of the scaffold, including biomolecules and/or cells incorporated within the scaffold.
[0037] In one embodiment, the biomolecule may comprise chemotactic agents; antibiotics, steroidal or non-steroidal analgesics, anti-inflammatories, immunosuppressants, anti-cancer drugs, various proteins (e.g., short chain peptides, bone morphogenic proteins, glycoprotein and lipoprotein); cell attachment mediators; biologically active ligands; integrin binding sequence; ligands; various growth and/or differentiation agents (e.g., epidermal growth factor, IGF-I, IGF-II, TGF-β I-III, growth and differentiation factors, vascular endothelial growth factors, fibroblast growth factors, platelet derived growth factors, insulin derived growth factor and transforming growth factors, parathyroid hormone, parathyroid hormone related peptide, bFGF; TGFβ superfamily factors; BMP-2; BMP-4; BMP-6; BMP-12; sonic hedgehog; GDF5; GDF6; GDF8; PDGF); small molecules that affect the upregulation of specific growth factors; tenascin-C; hyaluronic acid; chondroitin sulfate; fibronectin; decorin; thromboelastin; thrombin-derived peptides; heparin-binding domains; heparin; heparan sulfate; DNA fragments, DNA plasmids, or any combination thereof.
[0038] In one embodiment growth factors include heparin binding growth factor (hbgf), transforming growth factor alpha or beta (TGF.beta.), alpha fibroblastic growth factor (FGF), epidermal growth factor (TGF), vascular endothelium growth factor (VEGF), some of which are also angiogenic factors. In another embodiment factors include hormones such as insulin, glucagon, and estrogen. In some embodiments it may be desirable to incorporate factors such as nerve growth factor (NGF) or muscle morphogenic factor (MMF). In one embodiment, TNF alpha/beta, or Matrix metalloproteinases (MMP's) are incorporated.
[0039] In another embodiment, the scaffold may comprise one or more of an autograft, an allograft and a xenograft of any tissue with respect to the subject. In one embodiment, the tissue is a homogenate, which in one embodiment comprises the scaffold used to repair, or in one embodiment, regenerate the same tissue, such as in one embodiment to grow bone tissue.
[0040] In another embodiment, the scaffold implanted may further comprise cells. In one embodiment, the cells are seeded on said scaffold, or in another embodiment, on the periphery of the scaffold. In another embodiment, the cells are stem or progenitor cells. In another embodiment, the method further comprises the step of administering cytokines, growth factors, hormones or a combination thereof to the subject.
[0041] In one embodiment, the scaffolds may comprise cells. In one embodiment, the cells may include one or more of the following: chondrocytes; fibrochondrocytes; osteocytes; osteoblasts; osteoclasts; synoviocytes; bone marrow cells; mesenchymal cells; stromal cells; stem cells; embryonic stem cells; precursor cells derived from adipose tissue; peripheral blood progenitor cells; stem cells isolated from adult tissue; genetically transformed cells; a combination of chondrocytes and other cells; a combination of osteocytes and other cells; a combination of synoviocytes and other cells; a combination of bone marrow cells and other cells; a combination of mesenchymal cells and other cells; a combination of stromal cells and other cells; a combination of stem cells and other cells; a combination of embryonic stem cells and other cells; a combination of progenitor cells isolated from adult tissue and other cells; a combination of peripheral blood progenitor cells and other cells; a combination of stem cells isolated from adult tissue and other cells; and a combination of genetically transformed cells and other cells. In another embodiment, any of these cells for use in the scaffolds and methods of the invention, may be engineered to express a desired molecule, such as for example heparin binding growth factor (hbgf), transforming growth factor alpha or beta (TGF.beta.), alpha fibroblastic growth factor (FGF), epidermal growth factor (TGF), vascular endothelium growth factor (VEGF), some of which are also angiogenic factors. In another embodiment expressed factors include hormones such as insulin, glucagon, and estrogen. In another embodiment factors such as nerve growth factor (NGF) or muscle morphogenic factor (MMF), or in another embodiment, TNF alpha/beta are expressed.
[0042] In one embodiment, the scaffolds of this invention is porous, wherein said pores vary in one embodiment in terms of depth, which may range in another embodiment, from about 1 to about 35000 μm, and in one embodiment, in terms of diameter, which may range in another embodiment from about 0.75 to about 1500 μm, or in another embodiment, a combination thereof, within said scaffold. In one embodiment, the ratio between the length of the scaffold and the height of the scaffold is larger than 10.
[0043] In one embodiment, the term “about” refers to a deviation from the range of 1-20%, or in another embodiment, of 1-10%, or in another embodiment of 1-5%, or in another embodiment, of 5-10%, or in another embodiment, of 10-20%.
[0044] In one embodiment the pores vary in diameter from about 1 to about 100 μm, or in another embodiment, from 100 to about 200 μm, or in another embodiment, from 200 to about 300 μm, or in another embodiment, from 300 to about 400 μm, or in another embodiment, from 400 to about 500 μm, or in another embodiment, from 500 to about 750 μm, or in another embodiment, from 750 to about 1000 μm, or in another embodiment, from 1000 to about 1500 μm, or in another embodiment, from 1500 to about 2000 μm, or in another embodiment, from 2000 to about 2500 μm, or in another embodiment, from 2500 to about 3000 μm, or in another embodiment, from 3000 to about 3500 μm
[0045] In one embodiment the pores vary in diameter from about 1 to about 100 μm, or in another embodiment, from 100 to about 200 μm, or in another embodiment, from 200 to about 300 μm, or in another embodiment, from 300 to about 400 μm, or in another embodiment, from 400 to about 500 μm, or in another embodiment, from 500 to about 750 μm, or in another embodiment, from 750 to about 1000 μm.
[0046] In another embodiment, the invention provides a solid porous scaffold, in which the pores form a channel, where, in another embodiment, the channels are distributed on the face of the scaffold, or in another embodiment, oriented along an axis, which in another embodiment, the width of said channel is greater at a point more proximal to the scaffold surface, than to its core. In one embodiment, the channel narrows from the periphery of the scaffold to its center. In some embodiments, pores situated closer to a surface of said scaffold have a diameter which is greater than pores situated further from said surface.
[0047] In one embodiment the pores, or in another embodiment channels formed by the pores are designed for a particular tissue formation, such as in one embodiment for regeneration of intestine tissue, or in another embodiment for kidney, or in another embodiment for bone, or in another embodiment for breast, or in another embodiment innervated tissue.
[0048] In one embodiment, the width of the channel varies between about 1 μm to 5 cm, or in another embodiment between about 1 μm to 200 μm, or in another embodiment between about 1 μm to 200 μm, or in another embodiment between about 200 μm to 400 μm, or in another embodiment between about 400 μm to 600 μm, or in another embodiment between about 600 μm to 800 μm, or in another embodiment between about 800 μm to 1 mm, or in another embodiment between about 1 mm to 5 mm, or in another embodiment, between 5 mm to about 1 cm, or in another embodiment, between 1 cm and 2 cm, or in another embodiment, between 2 cm and 3 cm, or in another embodiment, between 3 cm and 4 cm, or in another embodiment, between 4 cm and 5 cm.
[0049] In one embodiment, scaffolds that are non-uniformly porous are especially suited for tissue engineering, repair or regeneration, wherein the tissue is a connector tissue, or wherein the scaffold is utilized to engineer, repair or regenerate two or three, or more, tissues in close proximity to one another. A difference in porosity may facilitate migration of different cell types to the appropriate regions of the scaffold, in one embodiment. In another embodiment, a difference in porosity may facilitate development of appropriate cell-to-cell connections among the cell types comprising the scaffold, required for appropriate structuring of the developing/repairing/regenerating tissue. For example, dendrites or cell processes extension may be accommodated more appropriately via the varied porosity of the scaffolding material. In another embodiment, the permeability differences in the scaffolding material may prevent and enhance protein penetrance, wherein penetration is a function of molecular size, such that the lack of uniform porosity serves as a molecular sieve. It is to be understood that the gradient scaffolding of this invention may be used any purpose for which non-uniform porosity is desired, and is to be considered as part of this invention.
[0050] In another embodiment, the scaffold varies in its average pore diameter and/or distribution thereof. In another embodiment, the average diameter of the pores varies as a function of its spatial organization in said scaffold. In another embodiment, the average diameter of the pores varies as a function of the pore size distribution along an arbitrary axis of the scaffold. In another embodiment, the scaffold comprises regions devoid of pores. In another embodiment, the regions are impenetrable to molecules greater than 1000 Da in size.
[0051] In one embodiment, the term “average pore diameter” refers to area average diameter, D 3,2 . In another embodiment, D 3,2 is a measure of average pore diameter and in another embodiment follows a lognormal distribution. In one embodiment the term “D 3,2 ” refers to the average diameter of the pores calculated assuming spherical pores and inferring the average diameter from the surface area exposed to the measuring device.
[0052] In one embodiment, lognormal distribution will be determined according to the following formula for calculating the frequency distribution:
[0000]
df
=
1
σ
2
π
exp
[
-
(
d
p
-
d
A
)
2
2
σ
2
]
dd
p
Wherein:
[0000]
d p is the pore diameter in μM
d A is the average pore diameter
a is the standard deviation of pore sizes in μM
[0056] In one embodiment, the term “pore size distribution refers to σ, the standard deviation of pore sizes in μM.
[0057] In this aspect of the invention, and in one embodiment, the scaffolds of the invention vary in terms of their cross-link density. In another embodiment cross-link density may be modified by any crosslinking technology known in the art. In one embodiment the term “cross link density” refers to the average number of monomers between each cross-link. In another embodiment, the lower the number of monomers between cross links, the higher the cross link density, which, in another embodiment affects the physic-chemical properties of the scaffold. The cross-linking density should be controlled in one embodiment, so as to obtain a pore size large enough to allow cell migration. In another embodiment, pore size may be determined by scanning electron microscopy or in another embodiment, by using macromolecular probes. A cell suspension containing cells such as, in one embodiment, keratinocytes, chrondocytes and osteoblasts, is injected into the polymer network along with suitable growth factors. The cells would then be allowed to grow within the network. As the cells grow the network around them would degrade. The timing of the network degradation should coincide with the cells forming their own network (organ/tissue) through inter-cell contacts.
[0058] In one embodiment, the invention provides a process for preparing a solid scaffold, wherein the process further comprises exposing said scaffold to a cross-linking agent after applying a polymeric suspension to a mold comprised of a conductive material, wherein said mold has at least 2 components. In another embodiment, the cross-linking agent is glutaraldehyde, or in another embodiment formaldehyde, or in another embodiment paraformaldehyde, or in another embodiment formalin, (1 ethyl 3-(3-dimethyl aminopropyl)carbodiimide (EDAC), or in another embodiment UV light, or in another embodiment, a combination thereof. In one embodiment the exposure time vary to control the cross-link density as described hereinabove. In one embodiment, super-cooling the polymeric suspension under conditions inducing a gradient as described herein, creates a scaffold wherein the cross link density varies throughout the scaffold.
[0059] In one embodiment, the size and shape of said scaffold is a function of the tissue into which the scaffold is to be implanted.
[0060] In another embodiment, the scaffold, when implanted, promotes angiogenesis within, or proximal to the scaffold.
[0061] In one embodiment the scaffold is comprised of a material whose stiffness is sufficient to resist compressive forces of tissue proximal to a site of implantation. In another embodiment, the degree of cross-linking of the scaffold material is adjusted to compensate for the compressive forces of the surrounding tissue. In one embodiment, initial polymer slurry concentration is varied as a function of the compressive force of the target tissue. In one embodiment, the scaffold comprises plasticizers which impart some elasticity to the scaffold, yet preventing scaffold collapse. In one embodiment the scaffolds are so constructed so that the plasticizer is concentrated at the surface of the scaffold, or in another embodiment the concentration of the plasticizer will vary in depth and distribution to add elasticity and improve resistance to the compressive force of the surrounding target tissue.
[0062] In another embodiment, the plasticizer may be any substance of molecular weight lower than that of the biocompatible polymer that creates an increase in the free volume. In one embodiment, the plasticizer is an organic compound, which in one embodiment is triglyceride of varying chain length, or in another embodiment, the plasticizer is water.
[0063] In one embodiment, the scaffold is fabricated using a process that creates an amorphous glassy-state solid, comprised of a biocompatible polymer. In one embodiment “glassy-state solid” refers to an amorphous metastable solid wherein rapid removal of a plasticizer causes increase in viscosity of the biopolymer to the point where translational mobility of the critical polymer segment length is arrested and alignment corresponding to the polymer's inherent adiabatic expansion coefficient is discontinued.
[0064] In one embodiment, preparation of an amorphous glassy-state solid is accomplished by rapid cooling of an aerated melt of the biocompatible polymer, or in another embodiment by rapid solvent removal under vacuum, or in another embodiment, by freeze-drying. In one embodiment, preparing an amorphous glassy-state solid is accomplished by extrusion, which in one embodiment is at temperatures higher than 65° C. or, in another embodiment, at temperatures between about 4 and about 40° C. In one embodiment, width, length, depth, or a combination thereof, of the surface folds are designed into the dye used for extrusion, in conjunction with extrusion conditions. It will be understood by a skilled person in the art, that any process capable of producing amorphous glass with high portion of interconnected porosity (sponge-like) where the pore size is controllable by varying the fabrication conditions is appropriate for use for producing a scaffold of this invention and is thus within the scope of the invention.
[0065] In one embodiment, scaffolds are prepared according to the processes of this invention, in a highly porous form, by freeze-drying and sublimating the material. This can be accomplished by any number of means well known to one skilled in the art, such as, for example, that disclosed in U.S. Pat. No. 4,522,753 to Dagalakis, et al. For examples, porous gradient scaffolds may be accomplished by lyophilization. In one embodiment, extracellular matrix material may be suspended in a liquid. The suspension is then frozen and subsequently lyophilized. Freezing the suspension causes the formation of ice crystals from the liquid. These ice crystals are then sublimed under vacuum during the lyophilization process thereby leaving interstices in the material in the spaces previously occupied by the ice crystals. The material density and pore size of the ro resultant scaffold may be varied by controlling, in other embodiments, the rate of freezing of the suspension and/or the amount of water in which the extracellular matrix material is suspended at the initiation of the freezing process.
[0066] According to this aspect of the invention and in one embodiment, to produce scaffolds having a relatively large, uniform pore size and a relatively low material density, the extracellular matrix suspension may be frozen at a slow, controlled rate (e.g., −0.1° C./min or less) to a temperature of about −20° C., followed by lyophilization of the resultant mass. To produce scaffolds having a relatively small uniform pore size and a relatively high material density, the extracellular matrix material may be tightly compacted by centrifuging the material to remove a portion of the liquid (e.g., water) in a substantially uniform manner prior to freezing. Thereafter, the resultant mass of extracellular matrix material is flash-frozen using liquid nitrogen followed by lyophilization of the mass. To produce scaffolds having a moderate uniform pore size and a moderate material density, the extracellular matrix material is frozen at a relatively fast rate (e.g., >−1° C./min) to a temperature in the range of −20 to −40° C. followed by lyophilization of the mass.
[0067] In another embodiment, this invention provides a process for preparing a solid, porous, biocompatible scaffold having a width of at least 3.5 mm in at least one direction, and pores oriented perpendicular to an edge of said scaffold, the process comprising the steps of applying a polymeric suspension to a mold comprised of a conductive material, wherein said mold has at least 2 components; super-cooling the suspension-filled multicomponent mold in the previous step in a refrigerant held at a constant temperature, for a period of time until said suspension is solidified, whereby ice crystals are formed in said solidified suspension, said crystals being oriented perpendicular to an edge of said scaffold; exposing a portion of said solidified polymeric suspension by removing at least one component to conditions which enable sublimation in said portion, whereby pores are formed which are perpendicular to an edge of said scaffold; and removing the remaining components of said mold to expose said solid porous scaffold, thereby preparing a solid, porous, biocompatible scaffold.
[0068] In another embodiment, the invention provides a process for preparing any of the scaffolds described herein.
[0069] In one embodiment, “polymeric suspension” or “suspension” refers to any suspended system that would form a solid scaffold upon removal of one phase in the system. In one embodiment, the suspended system is a suspension, or in another embodiment an emulsion, or in another embodiment, a gel or in another embodiment, a foam. In one embodiment, the polymeric suspension is comprised of monomers or in another embodiment, single biocompatible molecules.
[0070] In one embodiment, the invention provides a process for preparing a solid scaffold, wherein the process further comprises super-cooling the suspension-filled mold in after applying a polymeric suspension to a mold, at a constant temperature, for a period of time until said suspension is solidified, whereby ice crystals are formed in said solidified suspension, said crystals being oriented perpendicular to an edge of said scaffold. In another embodiment, the solidified suspension or a portion thereof, is exposed to conditions which enable sublimation in the exposed region, where in another embodiment, pores are formed perpendicular to an edge of said scaffold, or in another embodiment, the pores formed vary in their diameter in the exposed region, relative to the unexposed region.
[0071] In one embodiment, the porous scaffold has “tunnels” which may be oriented in another embodiment from the periphery to the core of the scaffold, such that in one embodiment, the diameter of the tunnel narrows as a function of the distance from the periphery. In another embodiment the tunnels is the result of removal of mold components creating open tunnels leading from the periphery of the scaffold into the center of the scaffold. In one embodiment, removable of specific mold components, which in one embodiment may be at the surface of the scaffold, or, in another embodiment, at the interior and conditions for solidifying the suspension, may be such that tunnels are created.
[0072] According to this aspect of the invention, and in one embodiment, in order to produce a gradient scaffolding of this invention, the freezing rate is controlled, such that a thermal gradient is created within the scaffold, during its formation. For example, a slurry of interest comprising polymers as described and/or exemplified herein, may be inserted in a supercooled silicone oil bath, as described by Loree et al. (1989) Proc. 15 th Annual Northeast Bioeng. Conf., pp. 53-54). According to this aspect, in one embodiment, the container is only partially immersed, and is not completely submerged in the bath, such that a freezing front which travels up the length of the container is created, thereby creating a temperature gradient within the slurry.
[0073] In another embodiment, a solar bath effect is used to control ice crystallization rate and size in the mold, which facilitate control of the pore size in the lyophilized scaffold mass. In one embodiment, a solute is incorporated into the mass and a temperature gradient is induced by placing the pan containing the mass on a cold plate, which in one embodiment may be the freeze-dryer shelf, or in another embodiment a heat lamp may be placed on top of the pan. Since solubility is a function of temperature, a solute concentration gradient will result. In another embodiment, solute concentration affects the freezing temperature, resulting in different crystal size in a fixed freezing time, which, in a gradually concentrated solute will result in graduated porosity with pore size inversely proportional to the direction of increased solute concentration. In one embodiment, the solute comprises heterogeneous nucleation centers for water.
[0074] In one embodiment, the gradient is preserved by halting the freezing process prior to achieving thermodynamic equilibrium. The means for determining the time to achieving thermodynamic equilibrium in a slurry thus immersed, when in a container with a given geometry, will be readily understood by one skilled in the art. Upon achieving the desired temperature gradient, the slurry, in one embodiment, is removed from the bath and subjected to freeze-drying. Upon sublimation, the remaining material is the scaffolding comprising the polymer, with a gradient in its average pore diameter.
[0075] In another embodiment, a gradient in freezing rate of the scaffold is generated with the use of a graded thermal insulation layer between the container, which contains the scaffold components, and a shelf in a freezer on which the container is placed. In one embodiment, a gradient in the thermal insulation layer is constructed via any number of means, well known in the art, such as, for example, the construction of a thicker region in the layer along a particular direction, or in another embodiment, by varying thermal conductivity in the layer. The latter may be accomplished via use of, for example, aluminum and copper, or plexiglass and aluminum, and others, all of which represent embodiments of the present invention.
[0076] In one embodiment, the invention provides a process for preparing a solid porous, biocompatible scaffold of the invention which utilizes a mold with at least 2 components. In one embodiment, a multicomponent mold of a size and shape approximating the tissue into which said scaffold is to be implanted is used. In one embodiment, mold is comprised of two or more conductive materials, where, in another embodiment, the conductive materials differ in terms of their heat transfer coefficient, leading to difference in local rates of freezing during the super-cooling of the polymeric suspension. In one embodiment, each component of the multicomponent mold is comprised of a different conductive material.
[0077] In one embodiment, the invention provides a scaffold prepared according to the process described herein.
[0078] In another embodiment, the process further comprises the step of exposing the scaffold to a gradient of solutions, which are increased in their concentration of an enzyme, which degrades or solubilizes at least one extracellular matrix component. According to this aspect of the invention, and in one embodiment, digestion of at least one extracellular matrix component increases as a function of increasing enzyme concentration.
[0079] In one embodiment, the step of locally decreasing Tg to below that of the storage temperature, is followed by a change in environmental condition, increasing Tg such that the scaffold's Tg is above the storage temperature. In another embodiment, increasing Tg to above the storage conditions is achieved by dehydration of the matrix, which in one embodiment is done by exposing the matrix to temperatures lower than the desired Tg, or in another embodiment, by exposing the matrix to saturated salt solutions. In one embodiment, the saturated salt solution used is Lithium Chloride (LiCl), or in another embodiment Potassium Acetate (K + CH 3 COO − ) or in another embodiment to Phosphorous Pentoxide (P 2 O 5 ), or in another embodiment to a concentration of Sulfuric acid imparting relative humidity values of below 0.35. In one embodiment, when exceeding Tg is achieved by locally heating the scaffold, removal of the heating element will result in local cooling of the scaffold material to below Tg, thereby inhibiting further pore collapse according to the methods of the invention. In one embodiment, increasing Tg may involve cross-linking of the scaffold material, thereby increasing the critical segment length (x).
[0080] In one embodiment, controlled pore collapse is conducted along an axis of the scaffold. In one embodiment, water evaporation from regions of interest may be accomplished at appropriate pressure known in the art, such as, for example, through the use of hot air directed at the region. According to this aspect of the invention, the dried regions will be devoid of pores, or in another embodiment, will be diminished in terms of the extent of porosity in the region, by the controlled collapse of these pores, due to surface tension issues.
[0081] In one embodiment, the term degrade/s or solubilizes encompasses partial degradation or solubilization, or in another embodiment, complete degradation or solubilization.
[0082] In one embodiment, the invention provides a method of organ or tissue engineering in a subject, comprising the step of implanting a scaffold of this invention.
[0083] In another embodiment, this invention provides a method of organ or tissue repair or regeneration in a subject, comprising the step of implanting a scaffold of this invention in a subject.
[0084] According to these aspects of the invention, and in one embodiment, the scaffold may be one produced by a process of this invention.
[0085] In one embodiment, this invention provides an implantable gradient scaffold, which may have varying mechanical properties to fit the application as to the desired implantation site of the scaffold. For instance, the pore size and the material density may be varied to produce a scaffold having a desired mechanical configuration. In particular, such variation of the pore size and the material density of the scaffold is particularly useful when designing a scaffold which provides for a desired amount of cellular migration therethrough, while also providing a desired amount of structural rigidity. In addition, according to the concepts of the present disclosure, implantable devices can be produced that not only have the appropriate physical microstructure to enable desired cellular activity upon implantation, but also has the biochemistry (collagens, growth factors, glycosaminoglycans, etc.) naturally found in tissues where the scaffolding is implanted for applications such as, for example, tissue repair or regeneration.
[0086] In one embodiment, the method of the invention is used for wound healing.
[0087] In one embodiment, the term “wound” refers to damaged biological tissue in the most general sense. In another embodiment, the wound is a laceration of the skin. In one embodiments, the wound may be an abrasion of the skin with two separated parts of tissue which in another embodiment, need to be brought together. In one embodiments, the wound may refer to a surgical incision. In another embodiment, the wound may involve damage to lung tissue, arterial walls, or other organs with elastic fibers. In one embodiment, the wound may involve an abscess, or in another embodiment, the wound may be exacerbated by diabetes. In one embodiment, the methods and scaffolds of the invention are used to accelerate wound healing.
[0088] According to this aspect of the invention and in one embodiment, wound healing may comprise fibrin clot formation, recruitment of inflammatory cells, reepitheliazation, and matrix formation and remodeling and as such, the scaffolds of this invention in one embodiment or the methods in another, may incorporate molecules involved in these stages with the scaffold. In another embodiment, immediately after tissue injury, blood vessel disruption leads to the extravasation of blood and concomitant platelet aggregation and blood coagulation resulting in fibrin clot formation and similarly, the scaffolds of this invention in one embodiment or the methods in another, may incorporate molecules involved in this stage, or in another embodiment, its facilitation. Activated platelets trapped within the fibrin clot degranulate and release a variety of cytokines and growth hormones. These cytokines and growth hormones help to recruit inflammatory cells to the site of injury, to stimulate angiogenesis, and to initiate the tissue movements associated with reepitheliazation and connective tissue contraction. In one embodiment, the scaffold of the invention is comprised of invaginated surface topography, allowing for regrowth of disrupted blood vessels. In another embodiment, the scaffold further comprises cytokines and growth hormones.
[0089] In one embodiment, neutrophils and monocytes are recruited to the site of injury by a number of chemotactic signals including in another embodiment the growth factors and cytokines released by the degranulating platelets, formyl methionyl peptides cleaved from bacterial proteins, and the by-products of proteolysis of fibrin and other matrix proteins. Neutrophil infiltration ceases in one embodiment after a few days, but macrophages continue to accumulate by continued recruitment of monocytes to the wound site. Activated macrophages release growth factors and cytokines thereby amplifying the earlier signals from the degranulating platelets.
[0090] In another embodiment, formation of granulation tissue and reepithelialization of the wound starts. Reepithelialization is performed in one embodiment, by the basal keratinocytes which lose their attachments to the basal lamina and crawl over the provisional matrix of fibrin and fibronectin, and underlying matrix, followed by epidermal cells reproduction—thereby providing the replacement cells needed. Keratinocyte proliferation is regulated by keratinocyte growth factor and members of the epidermal growth factor (EGF) family, which in another embodiment are incorporated into the scaffolds, or in one embodiment, the methods of the invention. In order to migrate through the fibrin clot, the keratinocytes must dissolve the fibrin barrier in front of them. Plasmin is the chief fibrinolytic enzyme used in this process and as such may be incorporated in one embodiment into the scaffold of the invention and used in the methods of the invention in another embodiment. Reepitheliazation is made easier by the underlying contractile connective tissue, which shrinks to bring the wound margins toward one another. Epidermal migration ceases when the wound surface has been covered by a monolayer of cells.
[0091] In one embodiment, cells of the new epidermis undergo the standard differentiation program of cells in the outer layers of unwounded epidermis. A new stratified epidermis is, thereby, reestablished from the margins of the wound inward. Matrix formation and remodeling begins simultaneously with reepithelialization. The matrix is constantly altered over the next several months with the elimination of the fibronectin from the matrix and the accumulation of collagen that provides the residual scar with increasing tensile strength. As such molecules involved in inhibition of excessive scaring, or in one embodiment enzymes facilitating elimination of fibronectin, such as in another embodiment MMP's, may be incorporated in one embodiment into the scaffold of the invention and used in the methods of the invention in another embodiment. Elastin fibers, which are responsible for the elasticity of tissue, are only detected in human scars years after the injury. In one embodiment, the gradient scaffold of the invention is seeded with epidermis cells at the periphery of the scaffold and implanted into the wound, thereby accelerating healing of the wound.
[0092] According to this aspect of the invention and in one embodiment, a solid, porous, biocompatible gradient scaffold, seeded with epidermal cells and further comprising one or more extracellular matrix components or analogs thereof, is used to heal an open wound by implanting the scaffold into the wound, wherein the scaffold comprises elastin, neutrophils, monocytes and EGF. In another embodiment, the scaffold is additionally seeded with stem cells, which in one embodiment are engineered to express growth factors.
[0093] In one embodiment, the method and solid gradient scaffold of the invention is used for regeneration of breast tissue, following breast augmentation procedure. In another embodiment, following the incision and insertion of the gradient scaffold of the invention, inflammatory exudate starts to flow into the large open pore channels at the scaffold surface within the first few hours following implantation. Fibrin, formed from fibrinogen condenses creating a network on which blood vessels can grow. Other factors and cells present in exudate help reconstruct the stroma within the scaffold and promote angiogenesis. The vasculature in the pre-existing tissue becomes closer to the scaffold due to contraction of the surrounding tissue and increased pressure from the space taken up by the implant. An additional vascular network is also formed surrounding the scaffold as capsule forms. The high concentration of angiogenic factors in exudate and from migrating/seeded cells causes blood vessels to grow into the scaffold, supporting the nearby cells indefinitely.
[0094] The following examples are presented in order to more fully illustrate the preferred embodiments of the invention. They should in no way be construed, however, as limiting the broad scope of the invention
EXAMPLES
Example 1
Regeneration of a Large 3D Volume of Breast Tissue
[0095] The scaffold used is a sphere which is 50 mm in diameter, the pore structure form open channels at or near the surface which extend to the center of the scaffold. The diameter of these channels increases from the center to the scaffold surface, with the diameter near the surface as high as a few millimeters. As the channels extend toward the center they may divide to form a network of channels inside the scaffold, mimicking the progressive division of blood vessels in tissue. The scaffold is seeded with appropriate cells in the periphery. The cells extend from the outer surface to an approximate depth of 10 mm inside the scaffold. The scaffold also has VEGF bound onto the collagen fibers. The diameter of the pore channels at the scaffold surface is 1 mm.
[0096] The procedure for implanting the device is analogous to the procedure used to implant saline-filled breast implants. Saline-filled breast implants are fully coated implants available in fixed-volume, with a thick shell, a peripheral seam, and an internal septation, which divide the implant into compartments, intended to minimize bulging of one part of the implant when another part was compressed. Texturing of implant shells is intended to reduce capsular contracture. The incisions are made either directly below the nipple/areolar complex, in the crease below the breast, or in the axillary region, depending on the patient's anatomy and preference. The implants are usually placed underneath the pectorals (chest) muscle, as saline implants in this location give the breast a much more natural feel and appearance. Nearly all breast tissue may be visualized in mammograms with the implants under the muscle; less so when it is placed over the muscle
[0097] The scaffold is inserted by using a trans-axillary approach. The device is placed above the pectoralis major muscle. The placement of the scaffold above pectoralis major is expected to increase capsular contracture, and help bring the vascular bed in close proximity with the scaffold surface. The patient is placed under general anesthetic. Following the axillary incision the surgeon creates a small pocket to insert the scaffold between the breast gland tissue and pectoralis major. The scaffold is inserted into the space formed and the incision is closed. Following surgery the patient wears a specially designed undergarment to protect the device from being dislodged and from excessive compressive force. Pain medications are utilized as necessary following surgery. Once in place, the pressure from the surrounding tissue brings the existing vasculature in contact with the device's outer surface, forcing tissue into contact with the scaffold. The formation of capsule around the implant occurs spontaneously, creating multiple layers of fibrous tissue containing a variable amount of contractile cells, the innermost layers contain vasculature which is brought in close proximity to the scaffold. The degree to which capsule forms around the implant is dependant on the material from which it is composed, forming more around synthetic polymers.
[0098] Inflammatory exudate is released from capillaries in phases, bathing the wound created by the incision, in plasma proteins. Different cell types are recruited over time to remove damaged tissue, induce the formation of new tissue, reconstruct damaged matrix, basement membrane and connective tissue, and establish a new blood supply. Fluid exudate is released in three phases following injury: the first phase begins almost immediately after injury and involves a histamine-stimulated release of fluid and lasts anywhere between 8 to 30 minutes. The next phase is similar beginning straight after the first; it lasts longer, up to several days. The final phase commences a few hours after injury and the effects become maximal in 2-3 days, gradually resolving over a matter of weeks. Cellular exudate is produced in the second and third phases. The general make-up of the matrix becomes more fluid, allowing the contents of the exudate to diffuse more easily, but a sudden increase in tissue pressure doesn't occur. This will help exudate flow through the pores and channels in the scaffold, without a sudden increase in pressure damaging the implant. The components of exudate, both cellular and molecular (as detailed earlier) aid in angiogenesis and the regeneration of tissue.
[0099] The inflammatory exudate starts to flow into the large open pore channels at the scaffold surface within the first few hours following implantation. Fibrin, formed from fibrinogen condenses, creating a network on which blood vessels can grow. Other factors and cells present in exudate help reconstruct the stroma within the scaffold and promote angiogenesis. The vasculature in the pre-existing tissue comes closer to the scaffold due to contraction of the surrounding tissue and increased pressure from the space taken up by the implant. An additional vascular network is formed surrounding the scaffold as capsule forms. The high concentration of angiogenic factors in exudate and from migrating/seeded cells causes blood vessels to grow into the scaffold, supporting the nearby cells indefinitely.
[0100] By having oriented channels which can direct blood vessels growth, the channels in the scaffolds structure decrease the distance blood vessels travel through otherwise random angiogenesis to reach the center of the scaffold. They also decrease the amount of blood vessel growth required to vascularize the outer regions of the scaffold, thus rapidly vascularizing a large proportion of the volume of the implant (since x mm of blood vessel growth toward the surface fills a greater volume of scaffold than it would nearer the center).
[0101] The phase of cell proliferation begins early on at around 24-48 hours, peaking at around 2-3 weeks. Tissue remodeling begins from around 1-2 weeks. Near complete degradation of the scaffold and tissue regeneration is achieved within 4 weeks.
Example 2
Freeze-Sublimation Methods for Constructing Gradient Scaffolding with Varied Pore Diameter
Preparation of Slurry
[0102] Extracellular matrix components, such as, for example, microfibriallar, type I collagen, isolated from bovine tendon (Integra LifeSciences) and chondroitin 6-sulfate, isolated from shark cartilage (Sigma-Aldrich), 10% (w/w) at 1:1 ratio are combined with 0.05M acetic acid at a pH ˜3.2 are mixed at 15,000 rpm, at 4° C., then degassed under vacuum at 50 mTorr.
Varying Pore Diameter
[0103] The suspension is placed in a container, and only part of the container (up to 10% of the length) is submerged in a supercooled silicone bath. The equilibration time for freezing of the slurry is determined, and the freezing process is stopped prior to achieving thermal equilibrium. The container is then removed from the bath and the slurry is then sublimated via freeze-drying (for example, VirTis Genesis freeze-dryer, Gardiner, N.Y.). Thus, a thermal gradient occurs in the slurry, creating a freezing front, which is stopped prior to thermal equilibrium, at which point freeze-drying is conducted, causing sublimation, resulting in a matrix copolymer with a graded average pore diameter field.
[0104] In another method, the suspension is placed in a container, on a freezer shelf, where a graded thermal insulation layer is placed between the container and the shelf, which also results in the production of a gradient freezing front, as described above. The graded thermal insulation layer can be constructed by any number of means, including use of materials with varying thermal conductivity, such as aluminum and copper, or aluminum and plexiglass, and others.
[0105] In one embodiment, the container is a multicomponent mold, containing removable elements. In one embodiment, removal of these elements following solidification of the polymeric suspension creates tunnels within the frozen slurry, thereby optimizing their orientation. In another embodiment, the removable elements have conical shape, such that in one embodiment, the tunnel diameter narrows the further the distance is from the periphery of the scaffold.
[0106] In one embodiment, the surface of the mold creates indentations and channels in the frozen slurry, thereby creating surface folds of desired geometry and distribution across
[0107] The foregoing has been a description of certain non-limiting preferred embodiments of the invention. Those of ordinary skill in the art will appreciate that various changes and modifications to this description may be made without departing from the spirit or scope of the present invention, as defined in the following claims.
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This invention relates to a method for fabricating large scaffolds in a variety of shapes with an organized pore structure. The pore structure is organized such that pores are generally aligned perpendicular to the edges of the scaffold, regardless of-the particular macroscopic scaffold shape. Specifically, a freeze-drying based fabrication method for creating large, polymeric porous scaffolds for tissue engineering applications, with an organized pore structure of columnar pores extending from the scaffold periphery into the main mass of the scaffold.
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CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation application which is based upon and claims priority from prior U.S. patent Ser. No. 11/926,031, filed on Oct. 28, 2007, now U.S. Pat. No. 7,514,327 [Notice of Allowance mailed on Nov. 20, 2008], which is a divisional of prior U.S. patent Ser. No. 11/117,276, filed on Apr. 27, 2005, now U.S. Pat. No. 7,352,029, each of the aforementioned patent applications is herein incorporated by reference in their entirety.
FIELD OF THE INVENTION
The present invention generally relates to the field of semiconductor devices. More specifically, the present invention relates to a semiconductor multiplexing device that generates an electronically scannable conducting channel with two oppositely formed depletion regions. The multiplexing device has numerous applications. For example, the multiplexing device could be used to address multiple bits within a memory cell, or to connect nano lines to micro lines within a minimal space or could be used to build a nanoscale programmable logic array or to perform chemical and/or biological sensing at the nanoscale (molecular) level.
BACKGROUND OF THE INVENTION
Conventional memory devices are limited to mostly 1 bit at the intersection of a wordline (WL) and a bitline (BL) in a memory array. For example, DRAM devices are limited to 1 bit per intersection, which corresponds to the presence of only one capacitor at each node. Similarly, FLASH devices have at most 2 bits per cell, in a multibit or multilevel configuration. These 2 bits can be detected based on the magnitude and direction of the current flow across the cell.
However, conventional memory devices are not capable of easily accommodating more than two memory bits at every crosspoint intersection. It would therefore be desirable to expand the access capability in memory devices to select or read multiple bits at every memory area or crosspoint that is normally desired by one memory wordline and bitline.
One problem facing conventional semiconductor lithographic techniques is the ability to electrically interconnect nano-scaled lines or patterns (on the order of 1 nm to 100 nm) and micro-scaled lines or patterns (on the order of 90 nm or a feature that could be typically defined by semiconductor processes such as lithography). Such connection is not currently practical, as it requires a significant interconnect semiconductor area, which increases the cost and complexity of the manufacturing process or the final product.
It would therefore be desirable to have a multiplexing device or an addressing device that establishes selective contact to memory cells, logic devices, sensors, or between nano-scaled lines and micro-scaled lines within a minimal space, thus limiting the overall cost and complexity of the final product.
The need for such a multiplexing device has heretofore remained unsatisfied.
SUMMARY OF THE INVENTION
The present invention satisfies this need, and presents a multiplexing device capable of selectively addressing multiple nodes or cross-points, such as multiple bits within a volatile or non-volatile memory cell. This multi-node addressing aspect of the present invention uses the fact that wordline and bitline voltages can be varied in a continuous fashion, to enable the selection or reading of multiple states at every crosspoint.
The present multi-node addressing technique allows, for example, 10 to 100 bits of data to be recorded at a single node, or in general to access bits of data that are of the order of 100 times more densely packed than conventional lithographically defined lines. As used herein, a node includes for example the intersection of a wordline and a bitline, such as a memory wordline and bitline.
The multiplexing devices selectively generates a thin, elongated, semiconducting (or conducting) channel (or window) at a desired location within a substrate, to enable control of the width of the channel, from a first conducting sea of electrons on one side of the substrate to a second conducting sea of electrons on the other side of the substrate.
In one embodiment, the multiplexing device generates an electronically scannable conducting channel with two oppositely formed depletion regions. The depletion width of each depletion region is controlled by a voltage (or potential) applied to a respective control gate at each end of the multiplexing device.
In another embodiment, the depletion width is controlled from one control gate only, allowing the access to the memory bits for both the reading and writing operations to be sequential. Other embodiments are also contemplated by the present invention.
If the depletion width is controlled at both ends of the multiplexing device, along the same axis, the conducting channel can be small (e.g., sub 10 nm) to enable random access to the memory bits. This embodiment is applicable to random access memories, such as SRAM, DRAM, and FLASH, for embedded and standalone applications and to programmable logic arrays.
BRIEF DESCRIPTION OF THE DRAWINGS
The various features of the present invention and the manner of attaining them will be described in greater detail with reference to the following description, claims, and drawings, wherein reference numerals are reused, where appropriate, to indicate a correspondence between the referenced items, and wherein:
FIG. 1 is a schematic illustration of an exemplary multiplexing device of the present invention, comprising a scannable conducting channel having a relatively narrow width, shown in a first position within a scanning region;
FIG. 2 is a schematic illustration of the multiplexing device of FIG. 1 , showing the scannable conducting channel with a relatively wider width, in a second position within the scanning region;
FIG. 3 is a schematic illustration of another embodiment of the multiplexing device of FIGS. 1 and 2 , wherein the scannable conducting channel connects conducting lines, such as nano-scaled lines, on one side of the multiplexing device to electrodes on the opposite side of the multiplexing device;
FIG. 4 is a schematic illustration of yet another embodiment of the multiplexing device of FIG. 3 , wherein the scannable conducting channel connects conducting lines, such as nano-scaled lines, on one side of the multiplexing device to other conducting lines, such as nano-scaled lines, on the opposite side of the multiplexing device;
FIG. 5 is a schematic illustration of still another embodiment of the multiplexing device of FIG. 4 , wherein the scannable conducting channel connects conducting lines, such as nano-scaled lines, on one side of the multiplexing device to other conducting lines, such as micro-scaled lines, on the opposite side of the multiplexing device;
FIG. 6 is a schematic illustration of another embodiment of the multiplexing device of the previous figures, wherein the scannable conducting channel is curvilinearly (non-linearly) controlled, to connect non-coaxially (or coplanarly) disposed lines on both sides of the multiplexing device;
FIG. 6A is a schematic illustration of another embodiment of the multiplexing device of FIG. 6 , illustrating two discrete depletable regions separated by a transition region therebetween;
FIG. 7 is a schematic illustration of a further embodiment of the multiplexing device of the previous figures, wherein the scanning region is formed of a plurality of discrete regions;
FIG. 7A is a schematic illustration of a further embodiment of the multiplexing device of FIG. 7 , showing alternative embodiments of the discrete regions;
FIG. 8 is a schematic illustration of still another embodiment of the present invention, exemplifying a three-dimensional configuration comprised of a plurality of stackable multiplexing devices;
FIG. 9 is a block diagram illustrating a serial connectivity of a plurality of multiplexing devices of the previous figures;
FIG. 10 is a perspective view of an exemplary multi-node cross-point array configuration using a plurality of multiplexing devices of the previous figures, illustrating a two-dimensional architecture;
FIG. 11 is a schematic illustration of another exemplary multiplexing device of the present invention that is similar to the multiplexing device of FIG. 1 , where the depletion region is controlled by a single electrode;
FIG. 12 is a schematic illustration of the multiplexing device of FIG. 11 , wherein the scannable conducting channel connects conducting lines, such as nano-scaled lines, on one side of the multiplexing device to electrodes on the opposite side of the multiplexing device;
FIG. 13 is a schematic illustration of the multiplexing device of FIG. 1 , where the depletion region is controlled by applying a reverse bias to a p−n (or p+−n or n+−p junction);
FIG. 14 is a schematic illustration of another embodiment of the multiplexing device of FIG. 7A , showing alternative embodiments of the intermediate regions;
FIG. 15 is a schematic illustration of a semiconductor-on-insulator (e.g., SOI) MOSFET that shows the effects of a floating polysilicon region in the multiplexing device of FIG. 14 ;
FIG. 16 is an isometric, schematic illustration of the multiplexing device of FIG. 14 , rotated about its side; and
FIG. 17 is an isometric view of a multiplexing array formed of an array of multiplexing devices of FIG. 16 .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIGS. 1 and 2 illustrate an exemplary multiplexing device 100 of the present invention. The multiplexing device 100 comprises a conducting channel 110 that is controllably scannable within a scanning region 106 . A first gate oxide layer 104 is disposed intermediate the scanning region 106 and a first control gate 102 , at one end of the multiplexing device 100 . At the opposite end of the multiplexing device 100 , a second gate oxide layer 114 is disposed intermediate the scanning region 106 and a second control gate 116 .
When suitably biased by a potential V 1 , the first control gate 102 generates a first depletion region 108 in the scanning region 106 . Similarly, when the second control gate 116 is suitably biased by a potential V 2 , it generates a second depletion region 112 in the scanning region 106 . The first and second depletion regions 108 , 112 interact to generate the conducting channel 110 .
The width w 1 of the first depletion region 108 is regulated by the potential V 1 and the doping concentration in the scanning region 106 . Similarly, the width w 2 of the second depletion region 112 is regulated by the potential V 2 and the doping concentration in the scanning region 106 . As a result, the width and the position of the conducting channel 110 can be very precisely controlled. FIGS. 1 and 2 illustrate the conducting channel 110 at two different positions along the scanning region 106 , and having different widths.
In a structure that is suitable for the formation of multiplexing device 100 , the first and second control gates 102 and 116 , respectively, are formed of conductive layers. As used herein a conductive layer can be formed of any suitable conductive or semiconductive material. For example the conductive layer can be formed of copper, tungsten, aluminum, a silicided layer, a salicided layer, a semiconductive layer, or a conductive layer, such as metallic materials, polysilicon, silicon germanium, metallic composites, refractory metals, conductive composite materials, epitaxial regions, amorphous silicon, titanium nitride, or like conductive materials. Preferably, the conductive layers are formed of polysilicon layers that are doped with dopant atoms. Dopant atoms can be, for example, arsenic and/or phosphorus atoms for n-type material, or boron atoms for p-type material.
Although the first and second control gates 102 and 116 can be lithographically defined into two distinct sections that are oppositely disposed relative to the scanning region 106 , as illustrated in FIG. 1 , it should be clear that the first and second control gates 102 and 116 could be disposed at different positions relative to the scanning region 106 . In particular, while the multiplexing device 100 is illustrated as having a generally rectangular shape, it should be clear that multiplexing device 100 could assume various other shapes, such as circular, oval, square, and various other shapes. Some of these alternative designs for the multiplexing device 100 could require the allocation of the first and second control gates 102 and 116 at various positions that are not necessarily opposite.
The two distinct sections of the first and second control gates 102 and 116 can be of a different conductivity type, for example: one section can be n-type while the other section can be p-type dopants or the two regions could have different metals. Known or available masking and ion implanting techniques can be used to alter the doping of portions of conductive layers.
The first and second control gates 102 and 116 can have the same or different widths. The width of each control gate can, for example, exceed 1000 angstroms. The voltages V 1 and V 2 applied to the first and second control gates 102 and 116 , respectively, can vary between approximately 0 and +/−100 volts.
A dielectric first gate oxide layer 104 is formed intermediate the first control gate 102 and the scanning region 106 . Similarly, a dielectric second gate oxide layer 114 is formed intermediate the second control gate 116 and the scanning region 106 . As used herein a dielectric layer can be any insulator such as wet or dry silicon dioxide (SiO 2 ), hafnium oxide, silicon nitride, tetraethylorthosilicate (TEOS) based oxides, borophospho-silicate-glass (BPSG), phospho-silicate-glass (PSG), boro-silicate-glass (BSG), oxide-nitride-oxide (ONO), oxynitride materials, plasma enhanced silicon nitride (p-SiN x ), a spin on glass (SOG), titanium oxide, or like dielectric materials or composite dielectric films with a high k gate dielectric. A preferred dielectric material is silicon dioxide.
The scanning region 106 can be formed of any suitable, depletable material. In this exemplary illustration, the scanning region 106 is formed of a depletion region, such as silicon or polysilicon layer that is lightly doped with either an n-type dopant, or a p-type dopant. In this exemplary embodiment, the scanning region 106 is doped with an n-type dopant. The width of the scanning region 106 could exceed 5 nm. The various components of regions and layers of the multiplexing devices described herein, could be made using, for example, known or available methods, such as, for example, lithographic processes.
In operation, by varying the voltages V 1 and V 2 on the first and second control gates 102 , 116 , respectively, the conducting channel 110 is controllably scanned along the directions of the scanning arrows A and B, up and down the central column of the multiplexing device 100 . In the present exemplary embodiment, the width, w (e.g., w 1 , w 2 ) of the depletion regions 108 , 112 is determined by the following equation:
w= (2) 1/2 λ n ( v l ) 1/2
where λ n is the extrinsic Debye length of the conducting channel 110 ; v l is defined by (q*(V bi +V)/kT)−2 where V bi is the built-in potential and V is the applied voltage. For an n-concentration of 10**16/cc the maximum depletion width is on the order of 1 micron.
FIG. 2 is a schematic illustration of the multiplexing device of FIG. 1 , showing the scannable conducting channel 110 with a relatively wider width, in a second position within the scanning region 106 .
FIG. 3 illustrates another multiplexing device 200 according to an alternative embodiment of the present invention, wherein the scannable conducting channel 110 connects conducting lines 201 , such as nano-scaled lines 202 through 210 (e.g., having a width between approximately 5 angstroms and 1,000 angstroms), on one side of the multiplexing device 200 , to one or more electrodes 228 on the opposite side of the multiplexing device 200 . To this end, the multiplexing device 200 further includes a source 226 , a first oxide layer 222 , and a second oxide layer 224 .
In this exemplary embodiment, the first oxide layer 222 is in contact with the first control gate 102 and the first gate oxide layer 104 . Similarly, the second oxide layer 224 is in contact with the second control gate 116 and the second gate oxide layer 114 . The source 226 is formed intermediate the first oxide layer 222 and the second oxide layer 224 , in contact with the scanning region 106 , and the electrode 228 . Layers 222 and 224 serve to isolate the gate regions 102 and 116 from the electrode ( 228 ) and source ( 226 ).
The source 226 can be formed of a silicon or polysilicon layer that is doped with either an n-type dopant, or a p-type dopant. The source 226 could be formed of any conductive or semiconductive material that forms an electrical contact to the scanning region 106 and electrode 228 . In this exemplary embodiment, the source 226 is doped with an n+−type dopant. In operation, the conducting channel 110 is generated as explained earlier in connection with FIGS. 1 and 2 , and is scanned across the scanning region 106 to establish contact with the desired line, for example line 204 , allowing the source 226 to inject electrons through the conducting channel 110 , into the selected line 204 .
In FIG. 3 , the source 226 has an inner surface 236 that is illustrated as being generally flush with the oxide layers 222 , 224 . It should however be understood that the inner surface 236 A of the source 226 could alternatively be recessed relative to the oxide layers 222 , 224 , as shown in a dashed line. Alternatively, the inner surface 236 B of the source 226 could extend beyond the oxide layers 222 , 224 , as shown in a dashed line.
FIG. 4 illustrates another multiplexing device 300 according to the present invention. Multiplexing device 300 is generally similar in construction to the multiplexing device 200 of FIG. 3 , but is designed for a different application. The scannable conducting channel 110 of the multiplexing device 300 connects conducting lines 201 , such as nano-scaled lines 202 - 210 , on one side of the multiplexing device 300 , to other conducting lines 301 , such as nano-scaled lines 302 - 310 , on the opposite side of the multiplexing device 300 .
In this exemplary embodiment, the lines 301 are coaxially aligned with the lines 201 , so that the conducting channel 110 interconnects two aligned lines, such as lines 204 and 304 .
FIG. 5 illustrates another multiplexing device 400 according to the present invention. Multiplexing device 400 is generally similar in construction to the multiplexing device 300 of FIG. 4 , but is designed for a different application. The scannable conducting channel 110 connects conducting lines 401 , such as nano-scaled lines 402 - 405 , on one side of the multiplexing device 400 to other conducting lines 411 , such as micro-scaled lines 412 - 415 , on the opposite side of the device 400 (e.g., having a width that exceeds approximately 100 angstroms).
FIG. 6 illustrates another multiplexing device 500 according to the present invention. Multiplexing device 500 is generally similar in construction to the multiplexing devices 100 , 200 , and 300 of FIGS. 1-3 , but will be described, for simplicity of illustration, in connection with the design of multiplexing device 300 of FIG. 4 . The scannable conducting channel 510 is curvilinearly (non-linearly) controlled, to connect non-coaxially (or coplanarly) disposed lines 201 , 301 on both sides of the multiplexing device 500 .
In order to effect this curvilinear conducting channel 510 , the multiplexing device 500 is provided with four control gates 502 , 503 , 504 , 505 that are arranged in pairs, on opposite sides of the scanning region 106 . In this specific example, the control gates 502 , 504 are disposed, adjacent to each other, on one side of the scanning region 106 , and are separated by an insulation layer 512 . Similarly, the control gates 503 , 505 are disposed, adjacent to each other, on the opposite side of the scanning region 106 , and are separated by an insulation layer 514 .
Potentials can be applied independently to the control gates 502 - 505 , to generate a first depletion region 508 and a second depletion region 512 , so that the conducting channel 510 is curvilinear. To this end, control gates 502 and 503 are paired, so that when a potential V 1 is applied to the control gate 502 and a potential V 2 is applied to the control gate 503 , a first portion 520 of the conducting channel 510 is formed. Similarly, when a potential V′ 1 is applied to the control gate 504 and a potential V′ 2 is applied to the control gate 505 , a second portion 522 of the conducting channel 510 is formed.
Portions 520 and 522 of the conducting channel 510 are not necessarily co-linear, and are interconnected by an intermediate curvilinear section 524 . As a result, it is now possible to connect line 207 to line 305 even though these two lines are not co-linearly disposed. Other lines on opposite (or different) sides of the multiplexing device 500 could be interconnected by the conducting channel 510 , by independently scanning the first and second portions 520 , 522 of the conducting channel 510 , along the arrows (A, B) and (C, D), respectively.
While FIG. 6 illustrates only four control gates 502 - 505 , it should be clear that more than four gates can alternatively be used.
FIG. 6A illustrates another multiplexing device 550 according to the present invention. Multiplexing device 550 is generally similar in construction to the multiplexing device 500 of FIG. 6 . Similarly to FIG. 6 , the scannable conducting channel 510 is curvilinearly (non-linearly) controlled, to connect non-coaxially (or coplanarly) disposed lines 201 , 301 on both sides of the multiplexing device 550 . However, the switching device 550 comprises two discrete depletion regions 551 , 552 that are separated by an intermediate, electrically conducting transition region 555 .
In order to effect the curvilinear conducting channel 510 , the multiplexing device 500 is provided with four control gates 562 , 563 , 564 , 565 that are arranged in pairs, on opposite sides of the scanning regions 551 , 552 , wherein each pair of control gates is separated from the other pair by the intermediate transition region 555 . In this specific example, the control gates 562 , 564 are disposed, adjacent to each other, and are separated by the intermediate transition region 555 , while the control gates 563 , 565 are disposed, adjacent to each other, on the opposite side of switching device 550 , and are separated by the intermediate transition region 555 .
Potentials can be applied independently to the control gates 562 - 565 , to generate the first depletion region 551 and the second depletion region 552 , so that the conducting channel 510 is curvilinear. To this end, control gates 562 and 563 are paired, so that when a potential V 1 is applied to the control gate 562 and a potential V 2 is applied to the control gate 563 , a first portion 520 of the conducting channel 510 is formed. Similarly, when a potential V′ 1 is applied to the control gate 564 and a potential V′ 2 is applied to the control gate 565 , a second portion 522 of the conducting channel 510 is formed.
The switching device 550 further includes a plurality of gate oxide layers 572 , 573 , 574 , and 575 that separate the control gates 562 , 563 , 564 , and 565 from their respective depletion regions 551 , 552 .
While FIG. 6A illustrates four control gates 562 - 565 and one the intermediate transition region 555 , it should be clear that more than four gates and one intermediate transition region 555 can be successively used to form the switching device 550 .
FIG. 7 illustrates yet another multiplexing device 600 according to the present invention. Multiplexing device 600 is generally similar in construction to any of the previous multiplexing devices of FIGS. 1-6 , but will be described, for simplicity of illustration, in connection with the design of multiplexing device 200 of FIG. 3 . FIG. 7 illustrates the feature that the scanning region 616 could be continuous or formed of a plurality of discrete sub-regions, such as sub-regions 606 , 608 , 610 with boundaries 607 , 609 therebetween.
FIG. 7A illustrates a further multiplexing device 650 according to the present invention. Multiplexing device 650 is generally similar in construction to multiplexing device 600 of FIG. 7 . The scanning region 656 of multiplexing device 600 is formed of a plurality of discrete sub-regions, such as sub-regions 676 , 677 , 678 , with intermediate regions 680 , 681 , 682 therebetween. The intermediate regions 680 , 681 , 682 serve the function of extending the depletion regions 676 , 677 , 678 and further isolating the conducting channels from each other.
While only three intermediate regions 680 , 681 , 682 are illustrated, it should be clear that one or more intermediate regions may be formed. In this particular embodiment, the intermediate regions 680 , 681 , 682 are generally similar in design and construction, and are dispersed along the scanning region 656 . In another embodiment, the intermediate regions 681 , 682 are disposed contiguously to each other. The spacing between the intermediate regions 680 , 681 , 682 and the widths of all the regions in the embodiments described herein, could be changed to suit the particular applications for which the multiplexing devices are designed.
Considering now an exemplary intermediate region 681 , it is formed of two semiconductor layers 690 , 691 with an intermediate layer 692 having a high dielectric constant material that is sandwiched between the semiconductor layers 690 , 691 . According to another embodiment, the intermediate layer 692 is made of a semiconducting material that is different from that of layers 690 and 691 to form a quantum well structure.
Intermediate region 682 includes an intermediate region 699 that is generally similar to the intermediate region 692 . Alternatively, the intermediate regions 692 , 699 could have different work functions than the work function of semiconductor layer 691 so as to produce a quantum well function.
FIG. 8 illustrates another multiplexing device 700 of the present invention, exemplifying a three-dimensional configuration. Multiplexing device 700 is comprised of a plurality of stackable multiplexing devices, such as multiplexing devices 100 , 200 , 300 , 400 , 500 , 600 , that can be different or similar. Each of these stackable multiplexing devices can be independently controlled as described in connection with FIGS. 1-7 .
According to this embodiment, one, or a group of multiplexing devices 100 , 200 , 300 , 400 , 500 , 600 can be selected by applying suitable depletion potentials V 3 , V 4 , to two outer electrodes 703 , 704 , respectively. Once the multiplexing device or a group of multiplexing devices 100 , 200 , 300 , 400 , 500 , 600 is selected, the selected multiplexing device or a group of multiplexing devices 100 , 200 , 300 , 400 , 500 , 600 is operated individually, as described earlier. In addition, a high-K insulation layer (e.g., 711 , 712 , 713 , 714 , 715 ) is interposed between two contiguous multiplexing devices (e.g., 100 , 200 , 300 , 400 , 500 , 600 ).
FIG. 9 illustrates another multiplexing device 800 of the present invention, exemplifying the serial connectivity of a plurality of multiplexing devices, such as multiplexing devices 200 , 300 , 400 . Each of these serially connected multiplexing devices 200 , 300 , 400 can be independently controlled, and the output of one multiplexing device used to control the accessibility of the subsequent multiplexing device.
FIG. 10 is a perspective view of an exemplary multi-node cross-point array 900 using at least two multiplexing device, e.g., 200 , 300 whose respective outputs are selected as described above, onto output lines 201 , 301 , are selected as described above. The selected outputs are processed (collectively referred to as “processed outputs”), as desired, by for example, operational devices 950 . The processed outputs can be used directly, or, as illustrated in FIG. 10 , they can be further fed to one or more multiplexing devices, e.g., 400 , 700 , resulting in outputs that are fed to respective output lines 400 , 700 .
The operational devices 950 could be, for example, memory cells, logic devices, current-driven or voltage-driven elements, such as light emitters, heat emitters, acoustic emitters, or any other device that requires addressing or selective accessibility.
As an example, the operational device 950 can include a switchable element that is responsive to current change or voltage change, or phase change, resulting in change of resistance or magneto-resistance, thermal conductivity or change in electrical polarization. Alternatively, the operational devices can include a carbon nano tube, a cantilever, a resonance driven device, or a chemical or biological sensor.
FIG. 11 is a schematic illustration of another exemplary multiplexing device 1100 according to the present invention. The multiplexing device 1100 is generally similar in design and operation to the multiplexing device 100 of FIG. 1 , and comprises a conducting region 1112 that is controllably scannable within a scanning region 106 . The gate oxide layer 104 is disposed intermediate the scanning region 106 and the control gate 102 , at one end of the multiplexing device 1100 . At the opposite end of the multiplexing device 1100 , an insulator layer, such as an oxide layer 1114 , is disposed contiguously to the scanning region 106 . It should be clear that the insulator layer 1114 is optional.
The depletion region 1108 is controlled by applying a potential V 1 to the control gate 102 , in order to generate the conducting region 1112 . An important feature of the multiplexing device 1100 is to control the width w of the depletion region 1108 using a single control gate 102 . Unlike the multiplexing device 100 , the undepleted region 1112 of the multiplexing device 1100 is not necessarily a small region. It could, in some cases, encompass the entire scanning region 106 under the control gate 102 and the gate oxide 104 . As further illustrated in FIG. 12 , the multiplexing device 1100 enables concurrent multibit sequential programming.
FIG. 12 is a schematic illustration of the multiplexing device 1100 of FIG. 11 , wherein the scannable conducting channel 110 connects conducting lines, such as nano-scaled lines 201 , on one side of the multiplexing device 1100 to electrodes (or to a micro line) on the opposite side of the multiplexing device 1100 . Since the multiplexing device 1100 comprises a single control gate (or electrode) 102 , many nano-scaled lines 201 could be selected for any value of the control gate potential V 1 . This requires a serial access scheme as compared to a random access scheme used by the embodiments of FIGS. 1-8 .
FIG. 13 is a schematic illustration of a multiplexing device 1300 that is similar to the multiplexing device 100 of FIG. 1 , but without the two gate oxide layers 104 , 114 . In the previous embodiments, the depletion regions 108 , 112 were comprised, for example of a depletion region of a Metal Oxide Semiconductor (MOS) system. However, the depletion regions 108 , 112 of the multiplexing device 1300 of FIG. 13 form two p+−n junctions (or alternatively one p+−n junction) with the adjacent control gates 102 , 116 , respectively. In an alternative embodiment, the depletion regions 108 , 112 form two n+−p junctions (or alternatively one n+−p junction) with the adjacent control gates 102 , 116 , respectively.
By applying potentials V 1 and V 2 to the p+ regions (control gates 102 and 116 ), a conduction channel 110 could be formed in around the middle of the scanning region 106 . One of the advantages of this multiplexing device 1300 is that the breakdown voltages of p-n junctions can be higher than the gate oxide breakdown voltages. This means that higher voltages could be applied to the control gate 102 , 116 . This could also mean that the scanning region 106 could be bigger. In an alternative embodiment, the multiplexing device 1300 could be formed of a single control gate, such as control gate 102 .
In yet another embodiment, the depletion regions 108 , 112 of the multiplexing device 1300 are formed by Schottky barriers (Metal-semiconductor regions), wherein the first and second control gates 102 and 116 are formed of a metal material. The depletion width in the Schottky barrier is controlled much the same way as the depletion width in a p-n junction.
Similarly to the illustration of FIG. 3 , it is possible to select nano-scaled lines 201 by applying appropriate potentials V 1 and V 2 to the first and second control gates 102 , 116 , respectively, and connect it to the micro-scaled line or source 226 . Alternatively Schottky barriers (metal-n or metal-p) regions may be used to do the connection as well.
FIG. 14 is a schematic illustration of another multiplexing device 1400 according to the present invention. The multiplexing device 1400 is generally similar in function and operation to the multiplexing device 650 of FIG. 7A , and shows an alternative embodiment of the intermediate regions 1480 , 1481 , in order to illustrate an exemplary instance of nano-pillar addressing.
In this embodiment, the semiconducting depletion regions 676 , 677 , 678 are physically separated through a combination of dielectrics (e.g., oxide/nitride/high-K) and electrode/semiconducting regions that are referred to as intermediate regions 1480 , 1481 . This allows a reduction in the leakage between the bits and extends the range of the maximum depletion region possible. This may also allow low voltage operation. Though only three semiconducting depletion regions 676 , 677 , 678 and two intermediate regions 1480 , 1481 are shown for illustration purpose only, it should be clear that a different number of regions could alternatively be used.
Each semiconductor depletion region 676 , 677 , 678 is bounded by at least one thin dielectric layer, e.g., 690 , 691 , which is preferably but not necessarily composed of an oxide in order to passivate the sidewalls and to guarantee good electrical properties. Sandwiched between layers 690 and 691 in each intermediate region 1480 , 1481 is a high-K dielectric material 1491 , 1492 , respectively. This minimizes the voltage drop between the intermediate regions 1480 , 1481 while maintaining isolation. The high-K dielectric material 1492 could be any dielectric with a reasonable dielectric constant, wherein a higher dielectric constant provides better electrical properties.
Each of the intermediate regions 1480 , 1481 further comprises two side insulation regions on opposite ends of the high-K dielectric material 1491 , 1492 . More specifically, intermediate region 1480 further comprises two side insulation regions 693 , 695 , and intermediate region 1481 further comprises two side insulation regions 694 , 696 . Side insulation regions 693 - 696 isolate the high-K dielectric material 1491 , 1492 from the semiconducting depletion regions 676 , 677 , 678 .
Alternatively, each of the dielectric layers 690 , 691 comprises a thin dielectric material, typically oxide, that bounds the semiconducting depletion regions 676 , 677 , 678 . However, the intermediate regions 1480 , 1481 between the dielectric layers 690 , 691 are filled with a semiconducting material or a metal material to form regions 1491 , 1492 . Each of the regions 1491 , 1492 is preferably floating and its potential depends on the capacitive coupling of the different control electrodes 102 , 114 to these regions 1491 , 1492 .
This design is desirable for the following reasons. A heavily doped semiconductor or metallic region further minimizes the applied voltage requirements. In addition, the work function difference between the electrode/semiconductor region 1492 and the semiconductor region results in an inversion layer (thin layer of electrons) at the interface of the semiconducting depletion regions 676 , 677 , 678 . This allows the multiplexing device 1400 to work via the depletion of the inversion layer charge as opposed to a charge resulting from ionized dopant atoms, and therefore minimizes dopant fluctuation effects. In this case, insulation regions 693 - 696 are required to prevent shorting of the electrodes (i.e., 1491 , 1492 ) to the various semiconducting depletion regions 676 , 677 , 678 and to keep it electrically isolated. This effect is further illustrated in FIG. 15 using the example of a simple MOS device 1500 .
As further illustrated in FIG. 7A , the multiplexing device 1400 of FIG. 14 , wherein the scannable conducting channel 110 could be connected to conducting lines, such as nano-scaled lines 201 , on one side of the multiplexing device 1400 to electrodes (or micro lines) on the opposite side of the multiplexing device 1400 .
FIG. 15 illustrates the effect of including floating polysilicon/electrode regions ( 1491 and 1492 in FIG. 14 or 1525 in FIG. 15 ) in semiconducting structure 1500 . Structure 1500 is generally formed of a silicon on insulator (SOI) wafer with a thin (e.g., less than approximately 100 nm) silicon region on top of an insulator (oxide). The MOS device includes an n-channel device with n+ source regions 1505 and drain regions 1510 . The gate 1525 is formed of n+ polysilicon material. At zero bias gate, the potentials of the source 1505 and drain 1510 develop an inversion layer 1507 in the channel of semiconductor region 1515 . This inversion layer 1507 is generated because of the work function difference between the gate 1525 and the silicon/semiconductor 1515 . This work function difference causes the bands in the silicon 1515 at zero gate voltage to bend in much the same way as a transistor with positive applied bias. This inversion charge in the addressing scheme may be depleted in much the same way as dopant charge. One way to think about the transistor in FIG. 15 is that it emulates a negative threshold voltage transistor.
Referring now to FIG. 16 , it illustrates a multiplexing device 1600 according to the present invention. Multiplexing device 1600 is generally similar to multiplexing device 1400 of FIG. 14 , but is rotated about its side. Multiplexing device 1600 comprises a plurality of nano-pillars 1676 , 1677 , 1678 , 1679 that are interposed between the first control gate 102 , the second control gate 116 , and intermediate regions 1610 , 1615 , 1620 . The intermediate regions 1610 , 1615 , 1620 are generally similar in construction and operation to the intermediate regions 1480 , 1481 of FIG. 14 . While four nano-pillars 1676 , 1677 , 1678 , 1679 are illustrated, it should be clear that a different number of nano-pillars can be selected. A plurality of oxide/dielectric layers 1686 , 1687 , 1688 surround the intermediate regions 1610 , 1615 , 1620 to isolate them from the nano-pillars 1676 , 1677 , 1678 , 1679 , and the operational devices 1635 , 1645 .
Arrows C indicate the direction of the electrical currents flowing through one or more nano-pillars 1676 , 1677 , 1678 , 1679 selected by depletion, as described earlier. While the direction of the current is shown in the current direction, it should be clear that the current could alternatively flow in the opposite direction. The current flows between the two electrodes 1602 , 1604 , through operational devices 1635 , 1645 (denoted earlier as operational devices 950 ).
FIG. 17 shows a multiplexing array 1700 that is formed of an array of multiplexing devices 1600 of FIG. 16 , with the electrodes 1602 , 1604 , the operational devices 1635 , 1645 , and the control gates 102 , 116 removed for clarity of illustration. The plurality of multiplexing devices 1600 are separated and insulated by a plurality of insulation layers 1705 . The insulation layers 1705 are preferably, but not necessarily formed of oxide layers, and could alternatively be made of the same material as the intermediate region 1610 . While only four multiplexing devices 1600 are illustrated, it should be clear that a different number of multiplexing devices 1600 can alternatively be used.
It is to be understood that the specific embodiments of the present invention that have been described are merely illustrative of certain applications of the principle of the multiplexing device. Numerous modifications may be made to the multiplexing device without departing from the spirit and scope of the present invention.
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An electronically scannable multiplexing device is capable of addressing multiple bits within a volatile or non-volatile memory cell. The multiplexing device generates an electronically scannable conducting channel with two oppositely formed depletion regions. The depletion width of each depletion region is controlled by a voltage applied to a respective control gate at each end of the multiplexing device. The present multi-bit addressing technique allows, for example, 10 to 100 bits of data to be accessed or addressed at a single node. The present invention can also be used to build a programmable nanoscale logic array or for randomly accessing a nanoscale sensor array.
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BACKGROUND
[0001] 1. Technical Field
[0002] The present invention discloses a method and a process for extracting shale oil and gas by fracturing and chemical retorting oil shale in in-situ vertical well, in which shale oil is extracted in in-situ underground oil shale and is served as unconventional oil and gas energy for making up shortage of petroleum resources, and which belong to a technical field of retorting of petroleum.
[0003] 2. Description of the Related Art
[0004] At present, shale oil (artificial petroleum), which is used to substitute for naturally occurring petroleum, may be refined from shale oil by virtue of retorting technology, and is also used for electricity generation by utilizing combustion thereof. Under the current situation that price of the oil keeps high, shale oil refining has good economic benefits and is a most realistic available measure to make up shortage of naturally occurring petroleum. Electricity generation by oil shale has good economic, environmental and social benefits to these provinces and districts which encounter shortage of coals. However, production and development of shale oil always adopts conventional method of underground exploitation and on-ground retorting, which encounters lots of shortcomings
1). The on-ground retorting has large excavation cost. 2). The on-ground retorting needs large land-use footprint. 3). The on-ground retorting leads to a great deal of landslide in exploration area. 4). The tailings resulted from the on-ground retorting are difficult to be treated, and its bulk accumulation causes secondary pollution. 5). The tailings resulted from the on-ground retorting carry away lots of heat so that heat from the tailings is unavailable, which results in energy waste. 6). Waste gas and sewage obtained from the on-ground retorting causes excessive pollution of the environment.
SUMMARY
[0011] The present invention discloses a method and a process for extracting shale oil and gas by fracturing and chemical retorting oil shale in in-situ vertical well, which fundamentally solve the above mentioned shortcomings and problems caused by underground exploitation and on-ground retorting.
[0012] The following is a technical solution of a method for extracting shale oil and gas by fracturing and chemical retorting oil shale in in-situ vertical well disclosed in the present invention.
[0000] The method comprises:
drilling, depending on the situation of an oil shale stratum, a fractured burning well and several export production wells from the ground to the underground oil shale stratum, wherein the export production wells are distributed in a honeycombed manner around the fractured burning well as a center; establishing a fracturing chamber within the fractured burning well, to pressurizedly fracture out the oil shale stratum; injecting a highly pressurized medium for the oil shale stratum (air, water and quartz sand) into the fractured burning well, and fracturing out several cracks of 1 to 3 mm in the oil shale stratum, the cracks being filled with gap fillers (quartz sand), so as to establish oil gas passages; establishing a burning chamber within the fractured burning well, injecting a combustible gas and a combustion-supporting gas into the burning chamber, and, igniting the combustible gas so that the combustible gas is burning at a bottom of the burning chamber (to ignite combustible matter in the oil shale), to heat the oil shale stratum up to 550-600° C., to achieve heating and retorting of the oil shale so that the shale oil and gas are driven and extracted; exporting the shale oil and gas to the ground through the oil gas passage and the export production wells; introducing, in the oil shale stratum, an oxidant through the vertical well, to oxidize a sphaltenes and fixed carbon remained in the oil shale after being retorted, where the heat generated is used as a heat source for subsequent retorting, thereby achieving extraction of the shale oil and gas by underground in-situ continuous retorting of the oil shale; separating the exported shale oil and gas by a ground gas-liquid separator, and delivering the separated shale oil to a product tank for storage and sale; and, delivering combustible gas to a gas power package for power generation.
[0014] A process for implementing the mentioned method of extracting shale oil and gas by fracturing and chemical retorting oil shale in in-situ vertical well according to the present invention is disclosed. The process comprising the following steps of:
1). depending on distribution and strike of an oil shale stratum, selecting specific locations of a fractured burning well and export production wells, drilling a fractured burning well and several export production wells from the ground to the underground oil shale stratum, wherein a drilling depth of the fractured burning well should not penetrate through the oil shale stratum, the export production wells should penetrate through the oil shale stratum, and, the export production wells are distributed in a honeycombed manner around the fractured burning well as a center; 2). establishing a fracturing chamber within the fractured burning well, taking out a well casing, injecting a highly pressurized medium in to the oil shale stratum through the fractured burning well, pressurizedly fracturing out several cracks of 1 to 3 mm in the oil shale stratum, and filling the cracks with gap fillers (quartz sand), so as to establish oil gas passages; wherein the step 2) further comprises:
i). drifting and flushing the well; ii). running a hydraulic casing nozzle into a wellbore; iii). closing the casing and shale wall gaps to form a closed fracturing space; iv). implementing a hydraulic jet perforation, by the hydraulic casing nozzle, on the oil shale stratum, wherein a mortar containing base fluid (water) and sand-laden fluid at 20-35% is pumped at a cutting stage, and, when the sand-laden fluid is distanced from the nozzle at about 25 meters, pump speed is sharply increased to ensure that a sufficient pressure different (55-80 MPa) which is required to implement the hydraulic jet perforation is obtained; v). replacing fracture rocks from the perforation, after 2-3 minutes of operation of the hydraulic jet perforation; vi). pumping crosslinked carbamidine gel and sand (at a rate of 20-30: 40-60), to enhance an expansion strength; vii). discharging fluid after fracturing, and flushing the sand to support the cracks; viii). injecting a fluid temporary plugging agent into the wellbore; vi). lifting up a drilling tool to a designed position, to fracture a next stratum, and repeating the steps iii). to vi).;
3). establishing a burning chamber within the fractured burning well; wherein the step 3) further comprises:
i). flushing the well, to bring the sand-contained water within the fractured burning well onto the ground; ii). equipping a sealing casing onto a head of the fractured burning well and running the sealing casing till 0.5 meter under the oil shale stratum, and, closing the casing and the shale wall gaps by means of an expansion agent; iii). Equipping combustible gas and air introducing pipes and an electronic ignition system within the fractured burning well, and, closing the head, to form a burning chamber in a segment of the oil shale stratum; iv). delivering LPG and air into the burning chamber via a combustible gas delivery pipe, and, igniting the combustible gas by the electronic ignition system; v). heating the oil shale stratum to 550-600° C. after igniting the oil shale, stopping supply of the combustible gas when it is measured that temperature of the gas from the production well reaches 200° C. and, driving and extracting some of the shale oil and gas to a ground gas-liquid separator via oil gas passages and the export production wells;
4). continuing to inject highly pressurized air into the well, to oxidize a sphaltenes and fixed carbon remained in the oil shale after being retorted, under high temperature, so as to generate fresh combustible gas while driving and extracting the shale oil and gas to the ground via the oil gas passages and the export production well; 5). separating the exported shale oil and gas by the ground gas-liquid separator, and delivering the separated shale oil to a product tank for storage; and, 6). delivering the separated combustible gas, via the gas-liquid separator, to a gas power package for power generation.
[0035] There are six export production wells distributed in a honeycombed manner.
[0036] The highly pressurized medium is selected from air, water or mortar.
[0037] The oxidant is selected from air or oxygen-enriched gas.
[0038] The hydraulic casing nozzle mainly comprises an upper centralizer, an ejection gun, a check valve, a lower centralizer, a screen pipe and a guide shoe, wherein a surface of the ejection gun is provided with an ejection nozzle, the ejection nozzle has one end communicated with the casing by a nipple and the other end communicated with the screen pipe by the check valve, an outside of the nipple is cased with the upper centralizer, pipe wall of the screen pipe is uniformly distributed with several screen meshes, the lower centralizer is cased over the screen pipe, and, the guide shoe is secured to a top of the screen pipe.
[0039] The present invention has the following positive effects.
[0040] The shale oil is extracted in in-situ underground oil shale by a chemical heat treatment process of fracturing and chemical retorting the shale oil and gas, which avoids bulk exploitation of oil shale mine and averts environmental pollution brought by on-ground retorting. Secondly, underground continuous retorting is achieved by utilizing a sphaltenes and fixed carbon remained in the oil shale after being retorted, accordingly, the heat is self-sufficient. Thirdly, the chemical heat treatment process is neither a single physical heating process nor an underground spontaneous combustion process, pores in the rock are gradually increased during the course of reaction, and, it is suitable for most oil shale strata. The present invention has advantages of small investments, low operating costs, small environmental pollutions, high resource utilization rate, and fast yields of oil and gas, etc..
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] FIG. 1 is a principle diagram of a method for extracting shale oil and gas by fracturing and chemical retorting oil shale in in-situ vertical well according to the present invention;
[0042] FIG. 2 is a structural schematic diagram of distribution of vertical wells according to the present invention; and
[0043] FIG. 3 is a structural principle diagram of a hydraulic casing nozzle according to the present invention;
[0044] in which:
[0045] 1 . fractured burning well, 2 . export production well, 3 . gas-liquid separator, 4 . product tank, 5 . gas power package, 6 . oil shale stratum, 7 . other stratum, 8 . oil gas passage, 9 . material conveyor, 10 . discharge and transport machine, 11 . oil pump, 12 . crack, 13 . fracturing fluid tank, 14 . LPG storage tank, 15 . oxidant tank, 16 . upper centralizer, 17 . ejection gun, 18 . ejection nozzle, 19 . check valve, 20 . lower centralizer, 21 . screen pipe, 22 . guide shoe, 23 . casing, and, 24 . nipple.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0046] In order to provide a much clearer understanding of essences and characteristics of the present invention, implementation and positive effects of the present invention will be described hereinafter in detail in conjunction with these embodiments. It should be understood that the below description is not intended to limit the scope of the present invention.
Embodiment 1
[0047] Fuyu-Changchun Mountain Oil Shale Mine, in which a total reserves is of 45.274 billion tons, is taken as an implementation base. The oil shale has an average grade of 5.53%, an industrially developable resources total amount of 18 billions, an embedded depth of 160-800 meters with top and bottom strata of mousey shale, and an average thickness of 5 meters.
[0048] As shown in FIG. 1 , depending on distribution and strike of an oil shale stratum, specific locations of a fractured burning well and export production wells are selected, a fractured burning well 1 (a head of which has a diameter of 200 mm) and six export production wells 2 (a head of each of which has a diameter of 200 mm) are drilled from a underground rock stratum 7 to a underground oil shale stratum 6 (which is distanced from the ground at 380 meters). As shown in FIG. 2 , the six export production wells 2 are distributed in a honeycombed manner around the fractured burning well 1 as a center. The fractured burning well and the export production wells are drilled from the ground to the underground oil shale stratum, wherein a drilling depth of the fractured burning well should not penetrate through the oil shale stratum, the export production wells should penetrate through the oil shale stratum, and, the export production wells are distributed in a honeycombed manner around the fractured burning well as a center.
2). A fracturing chamber is established within the fractured burning well, a well casing is taken out, a highly pressurized medium is injected into the oil shale stratum through the fractured burning well, several cracks of 1 to 3 mm are pressurizedly fractured out in the oil shale stratum, and the cracks are filled with gap fillers (quartz sand), so as to establish oil gas passages. The step 2) further comprises:
i). drifting and flushing the well; ii). running a hydraulic casing nozzle into a wellbore; iii). closing the casing and shale wall gaps to allow the oil shale stratum to form a closed fracturing space; iv). implementing a hydraulic jet perforation, by the hydraulic casing nozzle, on the oil shale stratum 6 , wherein a mortar containing base fluid (water) and sand-laden fluid (at 20-35%) is injected from the fracturing fluid tank 13 into the oil shale stratum 6 by a material conveyor 9 (at a cutting stage), and, when the sand-laden fluid is distanced from the nozzle at about 25 meters, pump speed is sharply increased to ensure that a sufficient pressure different (55-80 MPa) which is required to implement the hydraulic jet perforation is obtained to fracture the oil shale stratum 6 to generate cracks 12 of 1-3 mm; v). replacing fracture rocks from the perforation, after 2-3 minutes of operation of the hydraulic jet perforation; vi). pumping carbamidine gel base fluid by an annular bore, in accordance with a design annular bore discharge capacity or at a maximum pump speed allowed by an maximum pressure of annular bore, and, pumping crosslinked gel and sand, in accordance with a design of an oil pipe, (to enhance an expansion strength); vii). discharging fluid after fracturing, wherein the quartz sand is remained to support the cracks, forming a plurality of oil gas passages 8 , the plurality of oil gas passages 8 being converged and communicated with the export production well 2 ; viii). injecting a fluid temporary plugging agent into the wellbore; iv). lifting up a drilling tool to a designed position, to fracture a next stratum, and repeating the steps iii). to vi).
3). A fracturing chamber is established within the fractured burning well. The step 3 ) further comprises:
a first step of, flushing the well, to bring the sand-contained water out of the well onto the ground; a second step of, equipping a sealing casing onto a head of the fractured burning well and running the sealing casing till 0.5 meter under the oil shale stratum, and, closing the casing and the shale wall gaps by means of an expansion agent; a third step of, equipping combustible gas and air introducing pipes and an electronic ignition system within the fractured burning well, and, closing the head, to form a burning chamber in a segment of the oil shale stratum; a fourth step of, delivering LPG and air from a LPG storage tank 14 and an oxidant tank 15 respectively through the fractured burning well 1 into the oil shale stratum 6 by a material conveyor 9 , and, igniting the combustible gas by the electronic ignition system; a sixth step of, heating the oil shale stratum 6 to 550-600° C. after igniting the oil shale, stopping supply of the combustible gas when it is measured that temperature of the gas from the production well 2 reaches 200° C. and, driving and extracting some of the shale oil and gas to a ground gas-liquid separator 3 via oil gas passages 8 and the export production wells 2 ; introducing an oxidant into the oil shale stratum 6 to oxidize a sphaltenes and fixed carbon remained in the oil shale after being retorted, where the heat generated is used as a heat source for subsequent retorting the subsequent oil shale progressively, wherein the generated shale oil and gas are passed through;
4). continuing to inject highly pressurized air (the air: 1000 m 3 per hour) from the oxidant tank 15 into the fractured burning well 1 by a material conveyor 9 , to oxidize asphaltenes and fixed carbon remained in the oil shale 6 after being retorted, under high temperature, so as to generate fresh combustible gas (while driving the shale oil and gas) to the gas-liquid separator 3 via the oil gas passages 8 and the export production well 2 , so that the underground in-situ extraction of the shale oil and gas is achieved; 5). separating the exported shale oil and gas by the ground gas-liquid separator 3 , and delivering the separated shale oil to a product tank 4 for storage and sale, by an oil pump; and, 6). delivering the separated combustible gas, via the gas-liquid separator 3 , to a gas power package 5 for power generation, by a discharge and transport machine 10 .
Embodiment 2
[0069] Qiangguo Oil Shale Mine, in which a total mining area is of 675.5 km 2 , the total resources is of 6.172 billion tons and the exploitable total resources is of 4.94 billion tons, is taken as an implementation base. The oil shale has an average grade of 5%, an embedded depth of 160-800 meters with top and bottom strata of mousey shale, and an average thickness of 6 meters.
[0070] As shown in FIG. 1 , depending on distribution and strike of an oil shale stratum, specific locations of a fractured burning well 1 and export production wells 2 are selected, a fractured burning well 1 (a head of which has a diameter of 200 mm) and six export production wells 2 (a head of each of which has a diameter of 200 mm) are drilled from a underground rock stratum 7 to a underground oil shale stratum 6 (which is distanced from the ground at 380 meters). As shown in FIG. 2 , the six export production wells 2 are distributed in a honeycombed manner around the fractured burning well 1 as a center. The fractured burning well and the export production wells are drilled from the ground to the underground oil shale stratum, wherein a drilling depth of the fractured burning well should not penetrate through the oil shale stratum, the export production wells should penetrate through the oil shale stratum, and, the export production wells are distributed in a honeycombed manner around the fractured burning well as a center.
2). A fracturing chamber is established within the fractured burning well, a well casing is taken out, a highly pressurized medium is injected into the oil shale stratum through the fractured burning well, several cracks of 1 to 3 mm are pressurizedly fractured out in the oil shale stratum, and the cracks are filled with gap fillers (quartz sand), so as to establish oil gas passages. The step 2) further comprises:
i). drifting and flushing the well; ii). running a hydraulic casing nozzle into a wellbore; iii). closing the casing and shale wall gaps to allow the oil shale stratum to form a closed fracturing space; iv). implementing a hydraulic jet perforation, by the hydraulic casing nozzle, on the oil shale stratum 6 , wherein a mortar containing base fluid (water) and sand-laden fluid (at 20-35%) is injected from the fracturing fluid tank 13 into the oil shale stratum 6 by a material conveyor 9 (at a cutting stage), and, when the sand-laden fluid is distanced from the nozzle at about 25 meters, pump speed is sharply increased to ensure that a sufficient pressure different (55-80 MPa) which is required to implement the hydraulic jet perforation is obtained to fracture the oil shale stratum 6 to generate cracks 12 of 1-3 mm; v). replacing fracture rocks from the perforation, after 2-3 minutes of operation of the hydraulic jet perforation; vi). pumping carbamidine gel base fluid by an annular bore, in accordance with a design annular bore discharge capacity or at a maximum pump speed allowed by an maximum pressure of annular bore, and, pumping crosslinked gel and sand, in accordance with a design of an oil pipe, (to enhance an expansion strength); vii). discharging fluid after fracturing, wherein the quartz sand is remained to support the cracks, forming a plurality of oil gas passages 8 , the plurality of oil gas passages 8 being converged and communicated with the export production well 2 ; viii). injecting a fluid temporary plugging agent into the wellbore; iv). lifting up a drilling tool to a designed position, to fracture a next stratum, and repeating the steps iii). to vi).
3). A fracturing chamber is established within the fractured burning well. The step 3) further comprises:
a first step of, flushing the well, to bring the sand-contained water out of the well onto the ground; a second step of, equipping a sealing casing onto a head of the fractured burning well and running the sealing casing till 0.5 meter under the oil shale stratum, and, closing the casing and the shale wall gaps by means of an expansion agent; a third step of, equipping combustible gas and air introducing pipes and an electronic ignition system within the fractured burning well, and, closing the head, to form a burning chamber in a segment of the oil shale stratum; a fourth step of, delivering LPG and air from a LPG storage tank 14 and an oxidant tank 15 through the fractured burning well 1 into the oil shale stratum 6 by a material conveyor 9 , and, igniting the combustible gas by the electronic ignition system; a sixth step of, heating the oil shale stratum 6 to 550-600° C. after igniting the oil shale, stopping supply of the combustible gas when it is measured that temperature of the gas from the production well 2 reaches 200° C. and, driving and extracting some of the shale oil and gas to a ground gas-liquid separator 3 via oil gas passages 8 and the export production wells 2 ; introducing an oxidant into the oil shale stratum 6 to oxidize a sphaltenes and fixed carbon remained in the oil shale after being retorted, where the heat generated is used as a heat source for subsequent retorting the subsequent oil shale progressively, wherein the generated shale oil and gas are passed through;
4). continuing to inject highly pressurized air (the air: 1000 m 3 per hour) from the oxidant tank 15 into the fractured burning well 1 by a material conveyor 9 , to oxidize a sphaltenes and fixed carbon remained in the oil shale 6 after being retorted, under high temperature, so as to generate fresh combustible gas (while driving the shale oil and gas) to the gas-liquid separator 3 via the oil gas passages 8 and the export production well 2 , so that the underground in-situ extraction of the shale oil and gas is achieved;
separating the exported shale oil and gas by the ground gas-liquid separator 3 , and delivering the separated shale oil to a product tank 4 for storage and sale, by an oil pump; and, delivering the separated combustible gas, via the gas-liquid separator 3 , to a gas power package 5 for power generation, by a discharge and transport machine 10 .
Embodiment 3
[0091] Referring to FIG. 3 , there discloses a hydraulic casing nozzle involved in embodiments 1 and 2 , it mainly comprises an upper centralizer 16 , an ejection gun 17 , a check valve 19 , a lower centralizer 20 , a screen pipe 22 , a guide shoe 23 , a casing 23 and a nipple 24 , wherein a surface of the ejection gun 17 is provided with an ejection nozzle 18 , the ejection nozzle 17 has one end communicated with the casing 23 by a nipple 24 and the other end communicated with the screen pipe 21 by the check valve 19 , an outside of the nipple 24 is cased with the upper centralizer 16 , pipe wall of the screen pipe 21 is uniformly distributed with several screen meshes, the lower centralizer 20 is cased over the screen pipe 21 , and, the guide shoe 22 is secured to a top of the screen pipe 21 .
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The present invention provides a method and a process for extracting shale oil and gas by fracturing and chemical retorting oil shale in in-situ vertical well. A vertical well ( 1 ) is drilled towards an underground oil shale stratum ( 6 ) and a highly pressurized medium is injected into the oil shale stratum. Cracks of 1 to 3 mm are fractured out in the oil shale stratum with the well serving as a center and are filed with gap fillers, so that oil gas passages ( 8 ) are established. Then, a heating apparatus is added into the oil shale stratum to heat the oil shale stratum to 550° C., the oil shale is initially retorted, the shale oil and gas are extracted, and the shale oil and gas are led out of the ground via the oil and gas channel. After that, an oxidizer is introduced for oxidization reaction with a sphaltenes and fixed carbon contained in the oil shale after being retorted, where the heat generated is used as a heat source for subsequent retorting, thus achieving underground in-situ shale oil extraction. This solves the problem that existing ground-level retorting has in terms of large recovery costs, difficult treatment of tailings, a variety of environmental issues, and large land-use footprint.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is related to fabrics having a fiber structure to which is applied low glass transition temperature viscous polymer adhesives.
[0003] 2. Description of Related Art
[0004] Current soft body armor systems made from woven fabrics require high weight density per unit area, partly in order to achieve less than 44 mm back face deformation (BFD) as required by NIJ standard 0101.04 Rev. A. BFD is an indicator of blunt trauma, the lower the BFD, the better the protection from blunt trauma. Although many soft body armor constructions can adequately stop ballistic projectiles, the shock associated with blunt trauma can still cause substantial injury or death. Consequently, high-end lightweight vests typically use hybrids of woven fabrics with substantial amounts of nonwoven laminated structures, such as Honeywell's Goldflex® or Spectrashield®.
[0005] U.S. Pat. No. 5,776,839 discloses the application of dilatant dry powders, with a typical composition consisting of carbon black, fumed silica (nano-silica), and a small amount of adhesive “glue” to ballistic fibers and fabrics.
[0006] U.S. Pat. No. 5,229,199 considered rigid composites of woven aramid fabrics coated with an adhesion modifier and imbedded in a matrix resin. The reduced friction and weakened interfaces led to improved ballistic performance. If friction is too high in a fabric, or if the matrix is too stiff, ballistic resistance is severely compromised.
[0007] Lee, Y. S. et al. (N.J. Advanced Body Armor Utilizing Shear Thickening Fluids, 23 rd Army Science Conference, 2002) consider shear-thickening suspensions of particles in conjunction with ballistic fibers.
[0008] U.S. Pat. No. 4,678,702 discloses discloses a protective laminate formed by bonding layers of Kevlar® fabric together by layers of Surlyn® under heat and pressure to cause the Surlyn® to flow into and encapsulate the yarn of the Kevlar® fabric.
[0009] Fabrics impregnated with solid adhesives, such as polyethylene film, in monolithic systems could lead to a significant loss of penetration resistance due to a combination of high stiffness, the processing conditions needed for impregnation and to the absence of some of the ballistically significant material, such as Kevlar®, a polyaramid available from E.I. du Pont de Nemours and Co, Wilmington, Del. (DuPont).
[0010] Woven fabric based soft body armors typically exhibit large BFD, thereby requiring higher basis weight for compliance with NIJ standard 0101.04 Rev. A. For example, current vests made of 100% woven Kevlar® can weigh more than 1.0 psf to achieve Level II protection under the NIJ standard. Some film-impregnated fabrics, (such as those with polyethylene film) are typically used in conjunction with untreated fabric layers, with the impregnated layers placed nearer the body to control BFD. Such hybrid systems are needed in order to compensate for the weight gain associated with film lamination and to minimize overall stiffness of the assembly. Nevertheless, such solutions often significantly compromise ballistic resistance.
BRIEF SUMMARY OF THE INVENTION
[0011] This invention is directed to penetration resistant article made from a plurality of fabric layers that include fibers and a polymer having a glass transition temperature in the range of −40 to about 0° C., and a zero shear melt viscosity of about 2×10 6 to about 10 13 poise at 20° C. and the article has an area density less than 1.5 lb/ft 2 and the polymer is 1 to about 8 percent by weight of the fabric.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The present invention provides for significantly reducing the area density of woven fabric systems for soft body armor systems by incorporating strain-responsive viscous liquid polymers, such as described in co-pending U.S. patent application assigned to DuPont, designated internally as KB-4800. Such systems have a superior balance of V 50 and BFD.
[0013] A reduction of about 20% in the basis weight from about 1 psf to about 0.84 psf has been demonstrated with this invention. In addition to reduced BFD well below 44 mm, V 50 remains relatively unaffected, despite using fewer ballistically significant Kevlar® layers, thus permitting basis weight reduction. V 50 is the critical velocity in meters per second (m/s) where half of the bullets are completely stopped by a panel and half penetrate through the panel.
[0014] Moreover, because of the strain-responsive nature of coated fabrics, the protective systems, vests for example, remain flexible and comfortable during normal usage, becoming locally rigid only upon impact at ballistic strain rates. Without being bound by any particular theory, it is believed that the adhesive polymer “ligaments” that are present at the yarn crossovers are broken and reformed as the viscous polymer is able to flow and recreate such “ligaments”. However, solid adhesives, such as Kraton®, do not exhibit this self-healing, most likely because they do not exhibit strain hardening as do the polymers of this invention. Diagonal stretch data in Table I demonstrates this difference. It has been further shown by analysis of recovered projectiles from ballistic tests that the fabrics coated with the subject strain responsive polymers, such as ethylene/methyl acrylate copolymer, poly(vinyl propionate) and poly(hexyl methacrylate) significantly stiffen up upon ballistic impact. Furthermore, cross-sectional images of captured projectiles indicate significantly higher projectile blunting and damage using the inventive system, which further attests to the better BFD performance.
[0015] The present invention utilizes small amounts of strain-responsive viscous liquid polymer with appropriate molecular weight and T g as described in KB-4800. Such polymers, when applied in small amounts in accordance with this invention, provides a flexible system that has a superior balance of BFD and V 50 at lower basis weight than currently possible. As noted above, these systems produce a significantly higher degree of projectile damage and blunting) that are often characteristic of non-woven systems such as Goldflex® or Spectrashield®, but with increased comfort.
[0016] Ballistic resistance of fiber fabrics is an extremely complex problem because of the interplay of a very large number of variables and the extremely short time (about 100 microseconds) of the event. Selecting an appropriate strain-responsive polymer that will perform satisfactorily against a large number of criteria is very challenging, especially since such material properties are not typically achieved at such high strain rates. Additional challenges arise in impregnating fabric and finally designing a low basis weight vest with the necessary balance of penetration resistance and protection from blunt trauma.
EXAMPLES
[0017] Advantages are further exemplified in the examples below. Plain weave fabric pieces of 840 denier (930 dtex) poly(para-phenylene terephthalamide) yarn available from DuPont under the trademark KEVLAR® were woven at 26×26 ends per inch (10.2×10.2 ends per centimeter) for use as the base fabric.
[0018] copolymer having a high MW of about 100,000 g/mol and a zero shear rate melt viscosity of 1×10 7 Poise (Po) at 20° C. measured by capillary viscometry is referred to as “E/MA-high”. It is available as Vamac® VCD 6200 from DuPont. An ethylene/methyl acrylate (38/62 w/w %) with a glass transition temperature of −32° C. having a medium Mw of about 40,000 g/mol and a zero shear rate melt viscosity of 6×10 6 Po at 20° C. and is referred to as “E/MA-medium”. It is an experimental grade made by DuPont.
[0019] Ballistic tests were conducted against a 0.357 magnum bullet, based on the test protocol for NIJ Level II as described in NIJ Standard-0101.04 entitled “Ballistic Resistance of Personal Body Armor”. The back face deformation of no more than 44 mm is required to meet the performance requirement. Results of the ballistic tests, including both V 50 and back face deformation were shown in Table I.
Examples 1-4
[0020] Twenty layers for each of the following fabric layers for Examples 1-4 were made into various composite structures of about 15″×15″ size panels with an area density of about 4.1 kg/sq m.
[0021] Example 1 was prepared by scouring, i.e., multiple water rinsings to remove finish oil (as disclosed in co-pending patent application, also assigned to Dupont and designated internally as KB-4805) and then coating the base fabric with about 4.7 wt % E/MA-medium from a 7% solution in toluene.
[0022] Example 2 was prepared by scouring and then coating the base fabric with about 4.9 wt % E/MA-medium from a 20% solution in toluene.
[0023] Example 3 was prepared by scouring and coating the base fabric with about 4.7 wt % with wt % E/MA-high from a 20% solution in toluene.
[0024] Example 4 was prepared by scouring and coating the base fabric with about 4.5 wt % E/MA-medium from a 15% solution in toluene.
[0025] It is noted that, with an area density of about 4.1 kg per square meter, Examples 1 to 4 all showed good ballistic V 50 and low back face deformation, i.e. 31 to 39 mm opposite the NIJ back face deformation requirement of less than 44 mm.
Comparative Example A
[0026] In this comparative example, twenty-one layers of the base fabric layer were made into a composite structure of about 15-inch×15-inch panels with an area density of about 4.1 kg/sqm. Ballistic tests, based on the same test protocol employed for Examples 1-4 for NIJ Level II were conducted.
[0027] The results, as shown in Table I, indicate that while its ballistic V 50 was acceptable, the back face deformations were marginal opposite the NIJ back face deformation requirement.
Comparative Example B
[0028] This comparative example was prepared by scouring and coating the base fabric with about 8.5 wt % E/MA-medium from a 7% solution in toluene. Nineteen layers of the coated fabric were made into a composite structure of about 15″×15″ panel with an area density of about 4.1 kg/sqm. Ballistic tests, based on the same test protocol employed for Examples 14 for NIJ Level II were conducted.
[0029] It is noted that the panel showed a poor ballistic V 50 value, which resulted in a penetration, by the 0.357 magnum bullet when tested at 436±10 m/sec.
Comparative Example C
[0030] This comparative example was prepared by laminating the base fabric layer with a layer of Surlyn® film of about 23 micrometers thickness under the press condition of about 127° C. and 100 psi for about 20 minutes. Surlyn® is available from DuPont. Seventeen layers were made into a composite structure of about 15″×15″ size panel with an area density of about 4.1 kg/sqm. Ballistic tests, based on the same test protocol employed for Examples 14 for NIJ Level II were conducted.
[0031] The results, as shown in Table I, indicate that the fabric layers laminated with Surlyn® film showed a poor ballistic V 50 which resulted in a penetration by the 0.357 magnum bullet when tested at 436±10 m/sec.
TABLE 1 # Area Example No. layers density BFD V 50 m/sec 1 20 4.1 33; 37 479 2 20 4.1 32; 38 467 3 20 4.1 39; 31 482 4 20 4.1 32; 35 476 Comp. A 21 4.1 40; 38; 41; 44 488 Comp. B 19 4.1 penetrated 439 Comp. C 17 4.1 penetrated 431 BFD was measured in mm based on a 0.357 magnum bullet at 436 ± 10 m/sec
Examples 5-9
[0032] Examples of woven polyaramid fabrics were coated with various amounts of either E/MA-medium or E/MA-high. For the comparative example, the fabric was coated with Kraton® a solid adhesive available from Kraton Polymers Co., Houston Tex. The test samples measured 6 cm×6 cm and were stretched by gripping at opposite diagonal corners. The testing essentially determines the in-plane shear deformation properties at low strain rates (0.2 inches/min), with the strain applied at a 45 degree angle to the warp and weft directions. The test is terminated at low forces relative to the strength of the fabric in order to protect the load cell and also to prevent fiber damage to the fabric so that multiple cycles could be applied to the same sample. Not intending to be bound by any particular theory, it is believed that initially the comparative examples and the working examples behave similarly. With increasing load, a large departure occurs as the “ligaments” of the polymer adhesives of the inventive examples are twisted and stretched, while in the comparative example, free twisting and sliding of the fiber bundles occur. Finally at higher extension levels “the ligaments” become over stretched and progressively break down until the fabric itself starts to become substantially loaded at the highest stresses. Diagonal stretch data is presented in Table 2.
TABLE 2 Example Coating Peak Force, gm 5 4.4% E/MA-high 1 st cycle 190 2 nd cycle 125 3 rd cycle (after 48 hrs) 160 6 6% E/MA-high 1 st cycle 290 2 nd cycle 170 3 rd cycle (after 48 hrs) 290 7 3.1% E/MA-med 1 st cycle 200 2 nd cycle 110 3 rd cycle (after 48 hrs) 120 8 6% E/MA-med 1 st cycle 220 2 nd cycle 160 3 rd cycle (after 48 hrs) 210 9 10% E/MA-med 1 st cycle 250 2 nd cycle 145 3 rd cycle (after 4 hrs) 225 D 7% Kraton ® 1 st cycle 900 2 nd cycle 210 3 rd cycle (after >3 hrs) 230
[0033] The fabrics impregnated with the ethylene/methyl acrylate copolymers show significant self-healing as indicted by maintaining peak forces through the stretching cycles. On the other hand, the solid adhesive as represented by Comparative Example D does not recover the first cycle peak forces upon subsequent cycles, thus indicating a lack of self-healing. The results illustrate the practical advantage of the liquid adhesives as strain hardening materials that stiffen upon ballistic impact and can repair themselves.
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A penetration resistant article with an area density less than 1.5 lb/ft 2 made of a plurality of fibrous fabric layers that have applied thereto about 1 to 8 percent by weight of a polymer having a glass transition temperature in the range of minus 40 to about 0° C. and a zero shear melt viscosity 2×10 6 to about 10 13 poise at 20° C.
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[0001] This application is a continuation-in-part of U.S. application Ser. No. 08/460,516, filed Jun. 2, 1995, which is hereby incorporated by reference for all purposes.
COPYRIGHT NOTICE
[0002] A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the xerographic reproduction by anyone of the patent document or the patent disclosure in exactly the form it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
MICROFICHE APPENDIX
[0003] The Microfiche Appendix (17 fiche with total of 1027 frames) includes source code for implementing an embodiment of the invention.
BACKGROUND OF THE INVENTION
[0004] The present invention is related to remote monitoring of computer programs and, more particularly, to a adding remote monitoring instructions to a computer program so that the execution of the computer program may be monitored at a remote site.
[0005] As computer systems increasingly become more powerful and complex, so too do the computer programs that operate upon these computer systems. The increased complexity has resulted in much longer development times. Currently, computer programs take months and sometimes years to progress from pre-alpha through beta and final release.
[0006] Developers have long realized that when a computer program is very complex, it is more efficient to have customers run the computer program (typically beta versions) so that the full functionality of the computer program in different environments may be exercised. Few developers have the people, machines and time to do the testing that may be provided by their customers.
[0007] There are many problems that are presented with beta testing computer programs. Many of the problems revolve around the fact that the developer is at a remote site from the customers. At the remote site, it is difficult for the developer to know what is happening on a customer's computer system. Most customers do not have the expertise or resources to effectively convey problems to the developer. Without adequate information, it may be nearly impossible for a developer to correct a problem.
[0008] The preceding is just one of the problems presented to a developer that is trying to develop a computer program that is running at a customer's site. Other problems include customers having platform differences, dealing with the evolving computer program through to final release, upgrading customers' computer programs, tracking bugs, analyzing multi-tasking or multi-threaded applications, and developing multi-vendor applications just to name a few.
SUMMARY OF THE INVENTION
[0009] The present invention provides innovative systems and methods for remotely monitoring the execution of computer programs. Monitoring instructions (or data collecting instructions) are added the computer program so that during execution of the program, data may be collected regarding the program execution. The collected data may be automatically sent to a remote system or site for analysis. The present invention creates little or no performance impact on the client yet provides valuable information to the developer of the program.
[0010] In one embodiment, the present invention provides a method of remotely monitoring execution of a computer program in a computer system, comprising the steps of: modifying the computer program to include at least one monitoring instruction; executing the computer program; the at least one monitoring instruction collecting data regarding the execution of the computer program; and sending the collected data to a remote system.
[0011] In another embodiment, the present invention provides a distributed computer system, comprising: a server computer; a client computer in communication with the server computer; and a computer program running on the client computer that includes monitoring instructions that collect and send data regarding execution of the computer program to the server computer.
[0012] In another embodiment, the present invention provides a computer program product for remotely monitoring execution of a computer program, comprising: a computer readable storage medium storing the computer program comprising: code that calls at least one monitoring instruction, the at least one monitoring instruction collecting data regarding the execution of the computer program; and code that sends the collected data to a remote system
[0013] Other features and advantages of the present invention will become apparent upon a perusal of the remaining portions of the specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] [0014]FIG. 1 illustrates an example of a computer system used to execute the software of the present invention;
[0015] [0015]FIG. 2 shows a system block diagram of a typical computer system used to execute the software of the present invention;
[0016] [0016]FIG. 3 is a block diagram of a distributed computer system where a server computer may remotely monitor execution of computer programs on client computers;
[0017] [0017]FIG. 4 is a high level flowchart of a process of remotely monitoring execution of a computer program;
[0018] [0018]FIG. 5 illustrates a mechanism operating systems utilize to access routines in a system library;
[0019] [0019]FIG. 6 illustrates utilizing hooks to intercept systems calls and PV API calls;
[0020] [0020]FIG. 7 is a table of types of end-run-conditions for computer programs and the information that may be available;
[0021] [0021]FIG. 8 is a high level flowchart of a process of end-of-run processing of a computer program;
[0022] [0022]FIG. 9 is a high level flowchart of a process of performing remote debugging of a computer program;
[0023] [0023]FIG. 10 is a high level flowchart of a process of remotely upgrading the version of a computer program;
[0024] [0024]FIG. 11 is a block diagram of a bug tracker interfacing with a computer system of the present invention;
[0025] [0025]FIG. 12 is a block diagram of a computer system remotely monitoring computer programs in a multi-tasking or multi-threaded environment;
[0026] [0026]FIG. 13 is a block diagram of a computer system remotely monitoring computer programs incorporating portions from multiple vendors; and
[0027] [0027]FIG. 14 shows an object code file augmented to include new data collection instructions.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0028] The present invention provides a remote data collection facility that may be utilized for developers to monitor a program under test (PUT). A PUT is therefore a computer program or application that has been distributed to a client (or other site) for which the developer would like to monitor the execution remotely. This remote monitoring may be performed from pre-alpha through beta and final release. In a preferred embodiment, the present invention is incorporated in PureVision (PV) which is available from Pure Software Inc., Sunnyvale, Calif.
[0029] In the description-that follows, the present invention will be described in reference to an IBM compatible computer running under one of the Windows family of operating systems. The present invention, however, is not limited to any particular computer architecture or operating system. Therefore, the description the embodiments that follow is for purposes of illustration and not limitation.
[0030] [0030]FIG. 1 illustrates an example of a computer system used to execute the software of the present invention. FIG. 1 shows a computer system 1 which includes a monitor 3 , screen 5 , cabinet 7 , keyboard 9 , and mouse 11 . Mouse 11 may have one or more buttons such as mouse buttons 13 . Cabinet 7 houses a CD-ROM drive 15 , a system memory and a hard drive (see FIG. 2) which may be utilized to store and retrieve software programs incorporating code that implements the present invention, data for use with the present invention, and the like. Although a CD-ROM 17 is shown as an exemplary computer readable storage medium, other computer readable storage media including floppy disks, tape, flash memory, system memory, and hard drives may be utilized. Cabinet 7 also houses familiar computer components (not shown) such as a central processor, system memory, hard disk, and the like.
[0031] [0031]FIG. 2 shows a system block diagram of computer system 1 used to execute the software of the present invention. As in FIG. 1, computer system 1 includes monitor 3 and keyboard 9 . Computer system 1 further includes subsystems such as a central processor 102 , system memory 104 , I/O controller 106 , display adapter 108 , removable disk 112 (e.g., CD-ROM drive), fixed disk 116 (e.g., hard drive), network interface 118 , and speaker 120 . Other computer systems suitable for use with the present invention may include additional or fewer subsystems. For example, another computer system could include more than one processor 102 (i.e., a multi-processor system) or a cache memory.
[0032] Arrows such as 122 represent the system bus architecture of computer system 1 . However, these arrows are illustrative of any interconnection scheme serving to link the subsystems. For example, a local bus could be utilized to connect the central processor to the system memory and display adapter. Computer system 1 shown in FIG. 2 is but an example of a computer system suitable for use with the present invention. Other configurations of subsystems suitable for use with the present invention will be readily apparent to one of ordinary skill in the art.
[0033] [0033]FIG. 3 is a block diagram of a distributed computer system where a server computer may remotely monitor execution of PUTs on client computers. A server computer 202 is in communication with multiple clients, of which clients 204 , 206 and 208 are shown. The server may communicate with the clients via transport mechanisms known in the art including HTTP, email, network of LAN or WAN, and the like. Additionally, the server and clients may communicate via a media like a floppy or tape as shown between the server and client 208 .
[0034] The computer system that monitors a PUT will be designated a “server” and a computer system on which the PUT executes will be designed a “client.” For simplicity, the server computer will be described as the computer system that performs development of the PUT and remote monitoring of execution of the PUT. However, the development and remote monitoring may be performed on entirely different computer systems and at different locations.
[0035] A client executes the PUT which includes additional monitoring instructions for collecting data regarding the PUT execution. The collected data may be stored locally on the client until it is transferred to the server for analysis. The collected data is sent or transferred to the server via a transport mechanism.
[0036] The present invention provides a platform independent application programming interface (API) for directing the data collection for an executing PUT. As shown, client 204 is operating under the Unix operating system. In contrast, client 206 is operating under one of the family of Windows operating systems. The API of the present invention (PV API) is portable as a same set of API calls apply to PUTs running on both operating systems. This functionality allows developers to create a single source tree across different platforms. Although platform-specific API calls may be provided, these calls will be ignored if the platform is incompatible.
[0037] [0037]FIG. 4 is a high level flowchart of a process of remotely monitoring execution of a PUT. The flowchart is divided into a server-side and a client-side to indicate on which computer systems the steps are performed. At step 302 , the PV API is installed on the server computer for remotely monitoring the PUT. In a preferred embodiment, the PV API calls are stored in a dynamic-link library (DLL). As will be discussed in more detail in reference to FIGS. 5 and 6, hooks that are available in Windows may be utilized to intercept the system calls. A similar mechanism may be utilized for Unix systems.
[0038] At least one PV API call is placed in the PUT source code at step 304 . The PV_Start call may be added to the PUT source code to start monitoring of the PUT during execution. Data will be collected regarding the execution and, in a preferred embodiment, the collected data will be automatically sent to the server. The data is typically collected until the PUT finishes execution. Other PV API calls may be utilized to customize the data collection. Thus, developers may dynamically change the data that will be collected over the application development cycle from pre-alpha to beta through final release.
[0039] At step 306 , the PUT is compiled and linked into an executable computer program. After the PUT is a computer program that incorporates remote monitoring instructions, the PUT is sent to the client. The PUT may be sent to the client in any number of ways including networks and magnetic media like floppies.
[0040] Once the PUT is installed on the client, the PUT is executed at step 310 . Although multi-tasking and multi-threaded applications perform tasks in parallel, each task or thread essentially operates by executing statements in sequential order. Accordingly, in discussing this figure, all applications will be generalized to this sequential execution of statements.
[0041] At step 312 , the next statement is retrieved. The client then determines if the statement is a PV API call at step 314 . If it is not, the PUT statement is executed at step 316 . A PUT statement is basically any statement that is not a PV API call for remote monitoring.
[0042] The client calls the PV API specified by the statement at step 318 . There are numerous types of PV API calls that may be called including calls that perform the following:
[0043] starting and ending a PUT run
[0044] controlling the amount of data being collected
[0045] logging unstructured data
[0046] inserting simple per-run data
[0047] inserting complex data fields
[0048] platform-specific functions
[0049] Thus, there are a variety of PV API calls that may be made at step 318 . However, the goal of most of the calls revolves around data collection regarding the execution of the PUT.
[0050] The PV API calls allow the developer to specify characteristics of the data that will be collected during a PUT run. For example, in addition to the developer being able to turn data collection on and off at locations in the PUT with PV_On and PV_Off, the developer is also able to specify that data collected under a given type should be discarded (e.g., to reduce the amount of collected data that is sent to the server). Additionally, the developer may specify that data collected will be stored in a database table with the calls PV_DBAddStringToRow and PV_DBAddIntToRow. Thus, the developer is provided great flexibility in specifying what data will be collected and how the data will be available.
[0051] At step 320 , it is determined whether the PUT is finished executing. If it is not, execution resumes at step 312 where the next statement is retrieved. Otherwise, the client performs END-HOOK data collection at step 322 . In a preferred embodiment, END-HOOK is the mechanism in Windows through which data is collected after the PUT terminates or crashes. In order to aid the developer in tracking down crashes, information regarding the hardware, operating system, PUT (e.g., version number), and the like may be automatically collected to indicate the environment of the client. In a preferred embodiment, this information is automatically collected with a single API call, PV_Start.
[0052] Once the data is collected regarding the PUT execution, the data is sent to the server at step 324 . Once at the server, the data may be analyzed. The data may be analyzed to fix bugs in the PUT, track feature utilization, optimize execution of the PUT, and the like.
[0053] [0053]FIG. 5 illustrates a mechanism operating systems utilize to access routines in a system library. A call table 402 is kept in memory and associates system calls to routines in a system library 404 . For each call, a pointer indicates the routine in the system library that should be executed for the call. For example, one call in the table would be the exit( ) call which would then result in executing a routine in the system library that exits or terminates the current process (with exit codes). In Windows, the call table is also called the Windows system table and the system library may be called the Windows run-time DLL. These structures are also available in Unix and other operating systems.
[0054] [0054]FIG. 6 illustrates utilizing hooks to intercept system calls and PV API calls. Utilizing hooks, a preferred embodiment of the invention intercepts the calls in the call table. A call table 452 is modified utilizing hooks to redirect the system calls to a PV library 454 . The PV library includes routines that include statements to facilitate remote monitoring of PUT execution. The routines in the PV library may also call routines in a system library 456 . In a preferred embodiment, the PV library is a Windows DLL.
[0055] Additionally, PV API calls are also added to call table 452 so that the appropriate routines in the PV library will be called. As an example, FIG. 6 shows that a PV API call PV_EndRunNow may cause the execution of the END_HOOK routine in the PV library. The PV_EndRunNow terminates the data collection on the client but allows the PUT to continue execution.
[0056] [0056]FIG. 7 is a table of types of end-run-conditions for PUTs and the information that may be available in each case. Correctly identifying and reporting the way a PUT finished execution provides significant information to a developer. In a preferred embodiment, there are seven ways in which a PUT may stop execution (which are shown in the table of FIG. 7):
[0057] 1. PUT Normal Exit—exiting by invoking a member of the exit family of routines or returning from the main routine
[0058] 2. PUT exec( )—invoking a different executable by successfully calling exec
[0059] 3. PUT Exception Caught by Developer—catching an exception or signal in an exception handler and invoking exit from the handler
[0060] 4. PUT Exception Uncaught by Developer—encountering an uncaught exception
[0061] 5. PUT Dies via uncatchable event—encountering an uncatchable event (e.g., stack overflow or kill process)
[0062] 6. Developer ends run before PUT ends—PV API call to stop data collection (PV_EndRunNow)
[0063] 7. PureVision Dies via an unexpected event—the data collection software of the present invention halts (e.g., power off or internal error)
[0064] All of the above end-of-run types except for 4. would pass through the modified call table. The information available indicates the information the present invention may analyze and include in the data collected that will be sent to the server.
[0065] [0065]FIG. 8 is a high level flowchart of a process of end-of-run processing of a PUT. When an end-of-run (i.e., the end of data collection except for the final data collection for the end-of-run) occurs, the routine END_HOOK is executed in the PV library at step 502 . The present invention includes a default for handing the end of run. By default the present invention automatically intercepts and reports end-of-run instances as follows.
[0066] At step 504 , the PUT run is classified. The PUT run is classified as either a normal or abnormal run. In Windows, an abnormal run is defined as a PUT that terminates with an uncaught exception or with a caught exception followed by a non-zero exit code. Similarly, on Unix an abnormal run is defined as a PUT that terminates with an uncaught signal or exits with a non-zero exit code.
[0067] Data is collected for the end-of-run at step 506 . As mentioned earlier, information regarding the hardware, operating system, PUT (e.g., version number), user identifier, PUT start time, PUT execution duration, exit code, exit exception, and the like may be automatically collected to indicate the environment of the client at an end-of-run. Additionally, in the event of an abnormal run, stack information of the client may be collected for analysis on the server.
[0068] At step 508 , the collected data is sent to the server. The server may then remotely analyze the data it receives. If the end of the PUT is reached at step 510 , the PUT is exited at step 512 . Otherwise, the PUT continues execution at step 514 . In a preferred embodiment, the collected data is automatically transmitted to the server without requiring the client to issue a command to send the collected data.
[0069] Although the present invention provides a default mechanism for handling end-of-run situations, it also allows the developer to customize end-of-run processing. The PV API PV_RegisterEndHook allows a callback function to be defined that will be utilized instead of the default end-of-run processing. The custom END_HOOK processing is shown as step 516 in FIG. 8.
[0070] [0070]FIG. 9 is a high level flowchart of a process of performing remote debugging of a PUT on the server. Some of the steps that may be utilized are not shown in the figure. For example, it is not shown that the PUT is linked into an executable program. However, these steps will be readily apparent to one of skill in the art.
[0071] At step 552 , the PUT is compiled with the source code including PV API calls to collect data for remote debugging. A module map is created during compilation and it is stored at step 554 . The module map is essentially a table that for each module in the PUT source code contains the address and offset of every function in the module. Typically, the module map is stored on nonvolatile storage (e.g., a hard drive) on the server.
[0072] The executable PUT is sent to the client at step 556 . On the client-side, the PUT is executed at step 558 . When an end-of-run is encountered, the END_HOOK directs the client to save both the call stack and the module list at step 560 . The call stack is a list of addresses of function calls that were sequentially invoked during the PUT execution. The call stack is therefore generated while the PUT runs.
[0073] The module list is a list of modules, including modules in the executable and any DLLs, along with the base address and size of each module. The module list is also created while the PUT runs.
[0074] At step 562 , the client generates a module name/relative virtual address (RVA) list. The module name/RVA list is generated from the call stack and the module list. The module name/RVA list shows the sequence of function calls as a list of module names and relative offsets into each module. Typically, the module name/RVA list is generated during end-of-run processing.
[0075] The module name/RVA list is sent to the server along with any other collected data at step 564 . On the server, a symbolic call stack is generated from the module map and the module name/RVA list at step 566 . The symbolic call stack is the sequence of functions calls including the module name, function name, and offset into the function for each call. Utilizing the symbolic call stack, the PUT may be remotely debugged on the server at step 568 . In a preferred embodiment, the present invention also reports uniqueness of the call stacks so that a developer may more quickly determine if the same problem is occurring on other clients' computers.
[0076] [0076]FIG. 10 is a high level flowchart of a process of remotely upgrading the version of a PUT. The present invention also provides bidirectional communication between the server and the client. The developer may inform the client of upgrades and/or automatically have new software (e.g., new products, versions or patches) downloaded onto the client's machine.
[0077] As an example, step 602 shows a PUT running on the client computer. During execution, a PV API call (e.g., PV_Start) sends the PUT version number to the server at step 604 . The server receives the PUT version number and determines if the version is current at step 606 . If the version is not current, the current version (or a patch) may be downloaded to the client at step 608 . Additionally, the client may be queried as to whether it is desirable to get an upgrade in the event that they would prefer to retain the older version for any number of reasons (e.g., stability).
[0078] Whether a new version is downloaded or not, the PUT continues execution at step 610 . Utilizing this process, the developer is able to accurately track which clients are running what versions of software. Additionally, as the developer is able to more quickly upgrade older versions, the testing of the program is more efficient as clients do not continue to run older versions reporting old problems or bugs.
[0079] [0079]FIG. 11 is a block diagram of a bug tracker interfacing with a computer system of the present invention. The present invention may also interface with commercially available (or ones created by the developer) bug tracking software. A distributed system including a server computer 652 and multiple client computers 654 are shown.
[0080] A bug tracking application 656 is designed to track the bugs that are found in the PUT and other information regarding the bug. When an event occurs during execution of the PUT that necessitates reporting (e.g., a bug), a PV API call is utilized to collect the data for reporting the event to the bug tracking application.
[0081] The bug tracking application may receive the information it requires directly from the clients or the clients may send information to the server with the server collecting the information. The server may then format the collected bug information and sends it to the bug tracking application. Additionally, a PV API call may send collected data to more than one server if this is desirable for the developer.
[0082] [0082]FIG. 12 is a block diagram of a computer system remotely monitoring PUTs in a multi-tasking or multi-threaded environment. It is desirable for developers to know how two or more programs (or threads) interact in a multi-tasking (or multi-threaded) environment. For example, it may be useful to know which application is the bottleneck, the sequence of application calls or what percentage of processor time is consumed by each application.
[0083] As shown, a server computer 702 is in communication with a client computers 704 and 706 . Programs A and B are running on one client and program C is running on another client. Although A and B are described as programs, they may also be threads of the same program. Programs A, B and C are running concurrently and separate data is collected for each program (although the data may be stored on the same hard driver, it is shown separate for clarity). In a preferred embodiment, PV_Start returns a handle that may be utilized to uniquely identify a program or thread. The other PV API calls may receive this handle as a parameter so that data for each program or thread is collected together.
[0084] In a preferred embodiment, the data collected for each program includes timestamps as to when the program began running. Additionally, information that indicates what program invoked another program may be collected. Once this collected data is received by the server, the server will be able to reconstruct the sequence of program execution on the clients.
[0085] [0085]FIG. 13 is a block diagram of a computer system remotely monitoring computer programs incorporating code portions from multiple vendors. A PUT may include code portions or sections from multiple vendors. However, each vendor should receive information specific to the code that they produced. As shown a PUT 752 includes code portions from vendors A, B, C, and D. When the code for a specific vendor is entered, a PV_Start call is made which returns a handle specifying the appropriate vendor (e.g., A). Other PV API calls may then be sent to the appropriate handle specifying which vendors' code has generated the call and in which file the collected data should be stored. Thus, data for each vendor may be collected and stored separately (although, of course, it may be on the same hard drive).
[0086] Although the above has described modifying the source code to include PV API calls for data collection, the present is not limited to any specific method. For example, the present invention may utilize object code processing that inserts the data collection instructions into the object code of the PUT.
[0087] [0087]FIG. 14 shows an object code file augmented to include new data collecting instructions. A preexisting object code file 802 (“OLDFILE.O”) is augmented by an expansion means 804 to include data collecting instructions for the present invention. An augmented object code file 806 (“NEWFILE.O”). Typically, the expansion means is a general purpose computer like the one shown in FIG. 1. As the expansion means operates on object code, remote monitoring may be performed on the final executable product, not just those portions for which source code is available.
[0088] The Microfiche Appendix includes source code for implementing an embodiment of the invention. The source is written in C++ and is designed for an IBM compatible computer running under one of the Windows family of operating systems.
[0089] Appendix A, a PureVision Unix & Windows API Specification, and Appendix B, a PureVision Programmers' Guide, are filed herewith as part of the application and are incorporated by reference for all purposes.
[0090] While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications and equivalents may be used. It should be evident that the present invention is equally applicable by making appropriate modifications to the embodiments described above. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the metes and bounds of the appended claims.
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Systems and methods for remotely monitoring the execution of computer programs are provided. Monitoring instructions are added the computer program so that during execution of the program, data may be collected regarding the program execution. The collected data may be automatically sent to a remote system or site for analysis. The monitoring instructions create little or no performance impact on the client yet provide valuable information to the developer of the program. Additionally, the monitoring instructions may be changes during computer program development.
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[0001] This application claims priority to copending U.S. provisional application entitled, “Georgia Panels” having ser. No. 60/409,657, filed Sep. 10, 2002, which is entirely incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to erosion control devices generally for use at construction sites.
BACKGROUND OF THE INVENTION
[0003] At construction sites there is usually a large amount of digging of ground, which results often in piles of loose dirt and gravel, or in large stretches of bare earth. Such earth or dirt piles, generally being non-compacted, and often even compacted, are subject to erosion by wind or, more particularly by rainfall. When such raw earth is adjacent to streets or roads, rain can and most often does, wash the dirt over the road, creating a muddy hazardous condition. When the raw earth is adjacent a drainage ditch or sump and drainage pipe, such can be clogged or even plugged or dammed by the dirt that is washed into the ditch, sump, and/or pipe.
[0004] It is usually the practice to place plastic sheeting between the raw earth and a street, road, or other path, which is done by driving spaced wooden stakes into the ground along the stretch to be protected, and tacking or stapling plastic sheeting thereto, to form a plastic fence or dam. Such an arrangement at least partially dams the flow of dirt (usually mud) but is subject to wear and tear, often collapsing when the dammed load becomes too great. This problem also arises when the plastic strip is used to protect a drainage ditch, for example.
[0005] In the case where a sump and/or drainage pipe is to be protected, the protective structure is not as simple. Generally, assuming, for example, a square shaped sump, a square ditch is dug paralleling the sides of the sump, and vertical steel posts are driven into the ground at the four corners of the square. These posts are cross braced at their tops and their verticality maintained usually by two-by-fours attached to diagonally opposed posts and to each other. It is the usual practice to stretch plastic or felt sheeting around the square formed by the posts, and material such as chicken wire can be used to support the fabric spans. It is often the case that a mesh material, known as silt fencing, is supported by the chicken wire instead of the plastic or felt. Silt fencing is commercially available and is a plastic mesh sheeting material which allows the passage of water, but blocks, at least to some extent, the passage of debris, e.g., earth and rocks. The material extends down into the trench and is covered by, for example, lumped dirt, to prevent debris passing through the bottom edge of the structure. The structure as just described is relatively expensive to construct and, further, can only be used once, having to be completely disassembled for removal.
[0006] It is desirable, therefore, that a relatively simple, effective erosion control arrangement that can be reused where needed be available that has the inherent versatility to protect a wide variety of situations from erosion, or the deleterious results thereof.
SUMMARY OF THE INVENTION
[0007] The present invention, in its basic form, is a panel formed of vertical and horizontal approximately one quarter inch in diameter metal rods, preferably aluminum, spaced approximately six inches apart and welded at their intersections. Such paneling is commercially available and is known as livestock fencing, and is both fairly rigid and strong.
[0008] In accordance with the principles of the invention, in a first embodiment thereof, assuming nine vertical rod panels of fencing, the two vertical end rods and the third, fifth, and seventh vertical rods extend below the lowest horizontal rod or to the lower ends of the vertical rods a distance of approximately one foot, while the alternate vertical rods (second, fourth, sixth, and eighth) extend below the lowest horizontal rod a distance of approximately three inches. It will be appreciated that there may be more or fewer vertical rods, with alternate rods being of different lengths. Additionally, while five horizontal rods are adequate for proper performance of the invention, there may be fewer or more such rods, depending on the particular need. A sheet of silt fencing material is attached at the top of the panel by puncturing it with the ends of the vertical rods, which extend slightly above the uppermost horizontal rod. When so punctured, with the rod ends extending therethrough, the top edge of the sheet is firmly attached to the panel. The lower ends of the short vertical rods are bent outward and puncture the lower portion of the silt fencing material, which is stretched taut, thereby fixing the sheet to the panel at the top and bottom.
[0009] Several panels can be joined together to form almost any desired shape by clamping the end vertical members at the top and bottom by means of hog rings, to be discussed more fully hereinafter, or other reusable clips. When so clamped, the panels may be moved or rotated relative to each other to form almost any desired polygonal shape.
[0010] In a second embodiment of the invention, a panel for use in such a milieu as road grading where it is impractical to trench the subgrade for controlling the flow of water. It may also be used for slope drain inlets for water velocity dissipation and one ditch paving. The panel is similar to the basic panel except, as will be seen hereinafter, the silt fencing material extends well past the lower end of the panel and is bent up and attached, as by hog rings to one of the intermediate horizontal rods, thus forming a pocket. The pocket may be filled with coarse sand or other suitable material so that the end of the completed panel functions as a sand bag to redirect flowing water, for example.
[0011] In still another embodiment of the invention, the panel of the first embodiment has a thin, flat aluminum strip affixed to the lower horizontal rod and extending the length of the panel with the plane of the strip being vertical. When the panel (or panels) is to be used where trenching is undesirable, such as on a grassy lawn, the panel is pressed down so that the aluminum strip makes a narrow cut in the ground but extends far enough into the ground to maintain the panel upright, in conjunction with the long vertical rods.
[0012] These and other features of the present invention will be readily apparent from the following detailed description, read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIGS. 1 ( a ) and 1 ( b ) are front and side elevation views respectively of the basic unit of the present invention
[0014] FIGS. 2 ( a ) and 2 ( b ) are views of a coupling means for coupling together two or more of the units for FIGS. 1 ( a ) and 1 ( b )
[0015] [0015]FIG. 3 is an elevation view of a prior art arrangement for erosion control;
[0016] [0016]FIG. 4 is a top plan view of the arrangement of FIG. 3;
[0017] [0017]FIG. 5 is a perspective view of the units of the present invention as used in erosion control;
[0018] [0018]FIG. 6 is a perspective view of the units of the present invention as used in erosion control;
[0019] FIGS. 7 ( a ) and 7 ( b ) are, respectively, front and side elevation views of a modified unit for controlling water flow as well as erosion control; and
[0020] FIGS. 8 ( a ) and 8 ( b ) are, respectively, front and side elevation views of a unit embodying the features of FIGS. 1 ( a ) and 1 ( b ) as modified for use in areas where trenching is undesirable.
DETAILED DESCRIPTION
[0021] FIGS. 1 ( a ) and 1 ( b ) are, respectively, a front elevation view and a side elevation view of the basic panel 11 of the present invention. Panel 11 comprises a plurality of spaced vertical rods 12 and rods 13 , and end rods 14 and 16 . The rods are, preferably, {fraction (3/16)}-¼ inch aluminum or galvanized steel, although other size rods of sufficient stiffness may be used. It is to be understood that there may be more or fewer vertical rods than the nine shown in FIG. 1( a ), however, in the interests of portability, the number of vertical rods is preferably in a range, for example, of six to ten or twelve. As can be seen in FIGS. 1 ( a ) and 1 ( b ) end rods 14 and 16 and rods 12 are longer than rods 13 , with which they alternate. The longer rods, as shown in FIG. 1( a ) penetrate deeply into the ground (shown as a wavy line) to anchor the panel securely in upright position. A plurality of spaced horizontal rods 17 extend across the panel and are welded or otherwise affixed at their junctions with the vertical rods. As can be seen more clearly in FIG. 1( b ), the vertical rods 12 , 13 , 14 and 16 extend slightly above the uppermost horizontal rod 17 . Also, as best seen in FIG. 1( b ), the lower ends of rods 13 are bent outward to form anchors 18 for a sheet 19 of silt fencing material, which is a fine mesh material of plastic or other suitable material. The sheet 19 is stretched tight and anchored at the top of the panel by penetration of the upper extensions of the vertical rods into the mesh of sheet 19 . As seen in FIG. 1( b ), sheet 19 has a flap overlap 21 at the bottom of the panel, upon which dirt, stones, bricks or the like may be placed to prevent silt from passing under the panel.
[0022] In use, the panel 11 is installed by the operator first digging a narrow trench approximately three inches deep. The bottom of the panel is then placed in the trench and the panel is forced down to make the bottom extensions of the vertical rods 12 , 14 , and 16 penetrate the ground to a depth where the bottom horizontal rod is at ground level or slightly below. The trench is then back filled.
[0023] As pointed out in the foregoing, one of the principal features of the present invention is that the panel 11 obviates the necessity of wood and/or steel posts to which it is time consuming to attach a long length of silt fencing material or other plastic sheeting. Where long lengths of silt blocking are required, individual panels may be movably coupled to each other by means of hog rings, as shown in FIGS. 2 ( a ) and 2 ( b ). Hog ring 22 which is generally made of a semi-pliable metal, is shown in its open position in FIG. 2( a ). In FIG. 2( b ), ring 22 is shown in its closed position, having been squeezed around the end rods 14 and 16 of two panels. Ring 22 holds the vertical rods 14 and 16 together, but permits rotation of the panels 11 relative to each other. Rings 22 should be used in more than one place on the end rods 14 and 16 , at the top and at the bottom end region, such as just below the lowermost horizontal rod 17 , for example. Thus several panels may be strung together to extend for any desired length. Further, where special shapes are required, the panels may be rotated relative to each other, as will be discussed hereinafter.
[0024] In FIGS. 3 and 4 there is shown a drainage pipe and square sump arrangement 23 . The pipe 24 opens into the sump 26 which forms a catch basin for water which is carried away by pipe 24 . A typical prior art arrangement for preventing silt, dirt, rocks, etc. from accumulating in the sump 26 comprises four metal rods 27 , preferably of steel, driven into the ground at the four corners of the sump 26 , spaced therefrom as best seen in FIG. 4. First 28 and second 29 bracing members extend between diagonally opposed rods 27 , forming an X configuration and are nailed or bolted together at their intersection. Members 28 and 29 may be, for example, wooden two-by-fours, and are notched at their ends to hold the posts 27 . Typically, a sheet of plastic or felt is stretched about the perimeter of the square thus formed. It can be appreciated that it takes time to assemble such an arrangement and, when it is no longer necessary, it is usually scrapped, having had a very specialized used.
[0025] [0025]FIG. 5 is a perspective view of the drainage pipe 24 and sump 26 shown in FIGS. 3 and 4, protected by four substantially identical panels 11 , as depicted in FIGS. 1 ( a ) and 1 ( b ) which are held together by hog rings 22 . Additional small hog rings or other type clips 32 are shown for additionally securing the top of the sheets 19 , each to its respective panel frame. When the silt barrier is no longer needed, it is only necessary to detach the hog rings 22 and take the four now separate panels away. The panels may be used again and again, it only being necessary to remove the dirty and clogged sheet 19 from each panel and replacing it with a clean sheet 19 .
[0026] [0026]FIG. 6 is a perspective view of another configuration of panels 11 for use with a tapered flume 33 amplifying into a drain pipe (not shown). In this arrangement, only two panels 11 are necessary to form an L-shaped barrier in front of the flume 33 , and, as in the configuration of FIG. 5, when no longer needed, the panels 11 can be disconnected and removed until needed again.
[0027] It is often the case, especially in construction projects such as road building, where erosion control involves the control of water flow. Thus, in road subgrading, prior art types of silt fences, as discussed hereinbefore, are not usable because of the need to dig a trench for the silt fence, which contractors do not want to do. Further, the prior art type of silt fence does not control silt laden water flowing parallel to it, nor is it usually strong enough to withstand incursion of water at high velocities. In FIGS. 7 ( a ) and 7 ( b ) there is shown the basic panel 36 of the invention for use in controlling water flow wherein the silt fencing material 19 extends much farther below the bottom horizontal bar 17 and is looped up and its end attached to one of the intermediate horizontal members 17 by any suitable means such as wire clips or hog rings (not shown), thereby forming a pocket 37 which is filled with sand or other water resistant material 38 , thereby forming a sand bag at the base of the panel 36 , which stems the flow of the water through the panel 36 . Because the panels 36 may be arranged when joined together in any desired configuration, they may be used to channel the water flow or to attenuate its velocity.
[0028] FIGS. 8 ( a ) and 8 ( b ) depict a modification 41 of the panel 11 of FIGS. 1 ( a ) and 1 ( b ). The modification comprises a thin horizontal strip 42 , preferably of suitable metal, welded to the lowermost horizontal strip 17 . When the panel 41 is to be used on a surface where trenching is undesirable, such as a grassy lawn, the strip 42 , preferably having a pointed lower edge 43 cuts a very narrow slit in the lawn upon downward pressure, thus allowing the vertical strips 12 , 14 , and 16 to be sunk below the lawn's surface for insuring a rigid upright panel.
[0029] It is to be understood that the various features of the present invention might be incorporated into other types of erosion control arrangements, and that other modifications or adaptations might occur to workers in the art. All such variations or modifications are intended to be included herein as being within the scope of the invention as set forth herein. Further, in the claims hereafter, the corresponding structure, materials, acts, and equivalents of all means or step-plus-function elements are intended to include any structure, materials, or acts for performing the functions in combination with other elements as specifically claimed.
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An erosion control device is a panel formed of spaced horizontal and spaced vertical rods joined together to create a frame upon which is mounted a sheet of silt fencing material. A plurality of such panels may be rotatably joined together to form different configurations of erosion control fencing. The panels are reusable and the silt fencing material may be replaced thereon. The silt fencing material may be used to form a pocket for sand, thus forming a sandbag at the base of the panel for controlling water flow. The panel may have affixed thereto at the base a narrow metallic strip for cutting into the ground as the panel is forced downward thereon.
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[0001] This is a continuation of application Ser. No. 08/087,178 filed Jul. 2, 1993, which is a continuation-in-part of application Ser. No. 07/960,085 filed Oct. 9, 1992.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of germicidal systems employing bacteria-destroying ultraviolet lights. In particular, the present invention relates to a system for producing an air flow through a baffled ultraviolet sterilization chamber mounted behind a wall or ceiling, wherein the ultraviolet light intensity, the air residency time, and the air exchange rate for the air volume in a given space, are such that a percentage of tuberculosis bacteria are destroyed that effectively prevents transmission of such disease by airborne sputum.
BACKGROUND OF THE INVENTION
[0003] Tuberculosis is the most common cause of death from infectious disease in the world today. It infects millions of people each year and causes hundreds of thousands of fatalities. The disease is particularly prevalent in less-industrialized countries where high population densities, poor sanitary conditions and a high percentage of individuals in poor health contribute to the spread of infectious diseases.
[0004] After a long period of declining rates of tuberculosis infection in the United Sates, it is believed that the infection rate is now increasing. The increasing rate is apparently due to a combination of factors. One factor is undoubtedly increased immigration from parts of the world with high rates of infection. For example, in the United States the case rate of tuberculosis per 100,000 population was 9.3 in 1985, resulting in over 22,000 cases and over 1,200 deaths. In Southeast Asia, both the case rate and the death rate are believed to be many times that, and immigrants from that part of the world now constitute 3 to 5% of new cases in the United States.
[0005] Another factor related to increased rates of tuberculosis infection appears to be the use of living quarters with high population densities and less-than-ideal sanitary conditions for persons in ill health who are susceptible to the disease. Such conditions are commonly found in shelters for the homeless, prisons and some nursing homes. Another important factor in the increased rate of infection is infections among patients with Acquired Immune Deficiency Syndrome (AIDS) and intravenous drug users.
[0006] Another reason for the recent increased incidence of tuberculosis is probably the failure of many medical professionals to diagnose and treat the disease early and properly. The relative rareness of the disease in the United States since the early epidemics resulted in an entire generation of health care workers without much experience in the disease. Further, diagnosing the disease is not always easy, for the symptoms are similar to the symptoms of many other disorders. Therefore, the disease is often misdiagnosed and mistreated, and the degree of infectiousness of the disease is underappreciated.
[0007] Even after it is recognized that a set of symptoms may indicate tuberculosis, the tests for the disease are somewhat imprecise and tend to require judgment by an experienced professional. For example, one diagnostic tool is chest x-rays which typically show apical-posterior segment cavitary changes in tuberculosis infected patients. However, in elderly individuals—who comprise a relatively large proportion of tuberculosis patients—lobar or patchy lower-zone shadows may simulate bacterial or aspiration pneumonia. Also, x-rays in the elderly may mislead the physician by showing a solitary pulmonary nodule or a pleural effusion. Another important tuberculosis test is the tuberculosis skin test, but a major disadvantage to the tuberculosis skin test is that it generates a high number of both false-positive and false-negative results. The most precise test is microscopic examination of a sputum sample, but this test may require the use of at least three separate samples of sufficient volume, which may require gastric aspiration or bronchoscopy in patients with low sputum production.
[0008] The normal body reaction to infection by is tuberculosis bacteria is to build a fibrous wall around each bacterium. Initially, a person may be unaware of any infection, but over a period of months or even years the infection produces inflammation and eventually destruction of tissue. The manifestations as the disease progresses generally include cough, fever, night sweats, hemoptysis, chest pain, weight loss and malaise. The usual treatment for tuberculosis is administration of drugs over a period of many months such as isoniazid, rifampin and pyrazinamide and ethambutol. Persons recently infected but with no active disease are usually given isoniazid preventive therapy, particularly if they have other risks such as malnutrition, gastrectomy, diabetes mellitus, pneumoconiosis, malignancy or if for some reason they have immunosuppression such as from corticosteroid therapy, renal impairment or HIV infection. In short, tuberculosis in a normal healthy patient is typically a disease that is curable by drugs, although the drug therapy is quite prolonged. A serious concern—and yet another reason for the recent increase in tuberculosis—is the development of drug-resistant tuberculosis. It is estimated that at least 5% of new cases are resistant to the usual drug therapy, and that the percentage in some areas of the United States is as high as 20%. While non-drug-resistant tuberculosis is typically 99% curable in patients with normal immune responses, drug-resistant tuberculosis is only about 50-60% curable. A related concern is drug therapy on non-drug-resistant tuberculosis for patients who are intolerant of the drugs. In those cases, drug therapy is complicated because the drug is effective against the infection but has serious adverse effects on the patient such as hepatitis or serious rashes.
[0009] Another concern is raised by the increasing incidence of non-tuberculosis mycobacterial pulmonary infections. Many such infections produce symptoms similar to those of tuberculosis infections, but may be more difficult to identify and treat. Moreover, they may be transmitted through the same means as tuberculosis and tend to infect the same types of susceptible individuals.
[0010] The transmission of the tuberculosis bacteria is accomplished almost exclusively by infected individuals expectorating microdroplets of bacteria-containing sputum by coughing or sneezing. These microdroplets are suspended in the air and are inhaled by other individuals in the vicinity. The bacteria typically lodges in the lower lung where it proliferates, and may be disseminated to other organs as well. The microdroplets of sputum which contain the bacteria may be very small—on the order of 0.01 microns. In fact, it appears that the smallest droplets are the most effective in communicating the disease since the smallest droplets stay airborne indefinitely and are easily inhaled to the lower lung where they are not readily removed. Studies have shown that aerosol droplets on the order of 1-5 microns are highly effective vehicles for transmitting the disease.
[0011] One controversial approach to combatting the disease has been the use of vaccines. However, the efficacy of tuberculosis vaccines is debatable. Even the trials which seemed to show some efficacy have shown less efficacy among adults than among infants and children. An additional objection to widespread vaccinations is that by inducing tuberculin reactivity in the population they would confound the detection and measurement of infections through the use of skin tests, since skin tests in vaccinated individuals would presumably result in a false-positive. This would severely curtail the practice of preventive drug therapy among infected patients who have not yet developed outward symptoms.
[0012] The airborne aspect of the disease has led toward systems for preventing the transmission of the disease which focus on filtration and sterilizing devices. One approach is the use of masks. Simple surgical masks are thought to be insufficient in view of the very small size of the sputum microdroplets which are effective in communicating the bacteria. Instead, disposable particulate respirators are recommended. The use of masks is fraught with practical difficulties; they are physically uncomfortable, they impair breathing (which is already impaired for many patients), and they disrupt speaking. To be effective at all, it would probably be necessary for the masks to be worn not just by the patients, but also by noninfected individuals. In view of the long distances that airborne microdroplets containing viable bacteria can travel, it would be necessary for the masks to be worn by noninfected individuals throughout the general vicinity of a patient and not just those in the immediate presence of a patient. Moreover, it is not known for certain whether the use of masks would actually be effective even if the practical problems were tolerated or overcome.
[0013] Another preventive measure which relies on the airborne aspect of the bacteria is the use of modified ventilation systems. It is currently recommended that facilities used for tuberculosis patients undergo certain minimum air exchange rates, under the theory that dilution of infectious air with clean air will reduce the concentration of bacteria and hence the likelihood of transmission of the disease. While this approach is theoretically sound, it is problematic in implementation. Modern buildings are normally designed with fixed ventilation systems which are not easily modified to produce the requisite air exchange rate. Even if they are suitably modified, they may be rendered ineffective by an open door or by shifting air-flow patterns. A high air exchange rate also increases cooling and heating costs. Finally, there is the issue of the ultimate disposition of the contaminated air that is removed, and whether it is appropriate to simply release it outside the facility.
[0014] Another approach to reducing the transmission of the disease is the use of high-efficiency filtration systems. For such a system to be effective, however, it must employ a very dense filter to trap very small particles. This entalls a powerful fan, high energy usage, loud noise, and meticulous installation and maintenance. There is also concern that the filters and the rest of the air-flow path may themselves become sites of bacteria colonization.
[0015] Yet another approach to reducing the transmission of the tuberculosis bacterial employs ultraviolet light as a germicide. It was discovered some time ago that airborne bacteria are susceptible to ultraviolet light in wavelengths of about 254 nm. Wells S. F., On Air - Borne Infection: II - Droplets and Droplet Nuclei, Am. J. Hyg. 1934 20: 611-8; Wells W. F., Fair G. M., Viability of E. Coli Exposed to Ultraviolet Radiation in Air, Science 1935; 82:280-1. That finding led to the development of systems using ultraviolet light as a germicide against airborne bacteria such as measles and tuberculosis. However, interest in such systems diminished when later investigators were unable to obtain the desired efficacy. Also contributing to the diminished interest in such systems was the recognition that ultraviolet lights produced harmful ozone and also produced skin and eye irritation. With the development of streptomycin and chemotherapy for tuberculosis treatment, the belief became prevalent that tuberculosis would be eradicated and that preventive systems would be unnecessary.
[0016] The systems that were developed using ultraviolet light as a germicide against tuberculosis were imprecise, marginally effective, and perhaps dangerous. The most common system simply employed ultraviolet lights mounted on or suspended from a wall or ceiling of a room. For example, a system employing lights suspended from the ceiling is described in some detail in Riley, R. Z., Knight, M. and Middlebrook, G., Ultraviolet Susceptibility of BCG and Virulor Tubercle Bacilli, Am. Rev. of Resp. Dis., 1976, 113:413. The problems in such a system are numerous. It relies completely on normal air circulation in the room where it is installed to bring the bacteria within range of the ultraviolet light. The normal circulation in a room may be too low for the ultraviolet light to destroy a necessary proportion of bacteria, or the normal circulation may be high enough but of a pattern that does not bring the airflow past the ultraviolet light. Moreover, there is no single test to determine whether the circulation rate and patterns are adequate or not for a given installation. Further, such systems quickly become contaminated by dust on the light bulbs which diminishes their effectiveness. From a safety standpoint, one of the greatest concerns is that the simple light shields used with such systems allow light to be reflected off the walls and ceiling and onto the skin and eyes of the occupants. The degree of danger associated with the indirect ultraviolet irradiation is disputed, but there is undoubtedly at least some danger if the period of exposure is prolonged. In explaining the necessary safety precautions, Riley, R. L. and Nordell, E. A., Clearing the Air, The Theory and Application of Ultraviolet Air Disinfection, Am. Rev. Respir. Dis. 1989 139:1286, stated:
[0017] Does germicide UV cause inflammation of skin and eyes? It can, but the standard set by the National Institute of Occupational Safety and Health (NIOSH) is very conservative. Overhead installations must be inspected for ‘hot spots’ (greater than 0.2 uW/cm 2 ) with a sensitive UV meter. Installers should anticipate readjusting fixture height up or down based on meter readings. Baffles designed to prevent direct eye contact will also need adjustment after the initial installation. Excessively reflective surfaces about fixtures may contribute to excess radiation, but this can be reduced with nonreflective paint or by spraying the surface with stove black. If the intensity of UV does not exceed 0.2 uW/cm 2 , the likelihood of skin or eye irritation is minimal during an 8-h exposure. Persons with especially sensitive skin, with systemic lupus erythematous, for example, may need to avoid exposure or take measures to protect their skin.
[0018] This illustrates some of the difficulties and dangers of employing ultraviolet lights behind a simple light shield; the light may generate dangerous and unpredictable “hot spots”, it is not appropriate for those with sensitive skin or eyes, and it requires careful consideration of the placement and the orientation and reflectivity of the surrounding surfaces. Finally, even if all those precautions are observed, the quote only indicates that skin and eye irritation is “minimal” rather than nonexistent and only for exposure periods of 8 hours. Of course, for the system to be effective against transmission of airborne disease in, for example, a patient room, it would have to operate continuously and not just for 8 hour periods. The article goes on to acknowledge that:
[0019] UV or disinfection that is inappropriately applied, poorly planned, or carelessly used may be ineffective, dangerous, and falsely reassuring. The guidelines and precautions listed above are not intended to enable a would-be user of UV to plan, purchase, install, or check the adequacy of a UV installation. Detailed instructions for UV installers have been published. However, there is currently little commercial interest in UV-for air disinfection and, therefore, little expert guidance for comprehensive planning and installation. Renewed consumer interest may stimulate the UV industry to correct this deficiency.
[0020] Notwithstanding the uncertainly expressed in the Riley and Nordell article regarding the dangers of ultraviolet radiation, that article is actually more cognizant of those dangers than much of the other literature on the subject. For example, the article by Riley, Knight and Middlebrook, supra, does not even mention the dangers to the skin and eyes of ultraviolet radiation, or any precautions that should be taken to minimize those dangers.
[0021] There are number of ultraviolet germicidal systems that have been patented, but as in the case of the scientific literature mentioned above, those patents teach little about the dangers of ultraviolet radiation and how to effectively minimize the dangers, or how to position and operate the devices to achieve the requisite bacterial kill rate to prevent transmission of disease.
[0022] For example, U.S. Pat. No. 3,975,790 by Patterson is for an ultraviolet lamp fixture used in combination with a conventional commercial vacuum cleaner, and U.S. Pat. No. 4,087,925 by Bienek is for a sterilizing hand dryer, in which ultraviolet lights are positioned within the housing of a blower that is used to dry wet hands, where the blower is of the type commonly used in commercial restrooms. The devices of Patterson and Bienek seem to include little or nothing for light baffling to prevent leakage of allowable light to outside the housing, and the patents teach nothing about optimal flow rates, air-exchange rates or other information for the effective use of the machines. The devices are obviously intended as general, and only partially effective, sterilizing tools rather than as comprehensive and predictably effective systems.
[0023] Another patent, U.S. Pat. No. 4,210,429 by Goistein, employs a “squirrel-cage” type blower which draws air into a housing through a air intake filter, through the blower, and through a sterilization chamber containing ultraviolet lights. The air leaves the sterilization chamber, passes through a second filter and a charcoal filter and finally exits through an outlet. The specification indicates that the purpose of the device is to remove “pollens, lung damaging dust, smoke, bacteria and any one of a number of other irritants and micro-organisms” and that it does so for “particles down to 0.3 microns in size with an efficiency of 99.9%”. The device is characterized as an “air purifier” rather than as a germicidal device; the use of three distinct filters including a very fine filter for removing extremely small particles, a charcoal filter for removing odors and a pre-filter for removing particles, is distinguishable in design and function from the present invention. This extensive filtration would require a high-capacity blower to achieve any effective air exchange rate. The device is not specifically designed for destroying the tuberculosis bacteria or any other specific bacteria, although it would obviously be effective in doing so to some extent. Therefore, the patent teaches nothing about the use of the device for that purpose or the optimal flow rates or positioning of the device for that purpose.
[0024] U.S. Pat. No. 5,074,894 by Nelson is for a hospital room to quarantine patients with tuberculosis or other respiratory diseases caused by airborne pathogens. Although one embodiment of the system includes an air circulation circuit with ultraviolet lights, the patent is directed primarily toward negative pressure and filtering aspects utilizing high-efficiency particulate air filters.
[0025] Other patents describing the use of ultraviolet light as a germicide against airborne bacteria include, U.S. Pat. Nos. 4,448,750 by Fuesting, 4,896,042 by Humphreys, 4,990,311 by Hirai and 4,047,072 by Wertz, 4,990,313 by Pacosz, 3,072,978 by Minto, 4,227,446 by Sore, 3,347,0235 by Wiley, 4,786,812 by Humphreys, 4,990,311 by Hirai, 4,931,654 by Horng, 4,806,768 by Keutenedjian, 4,750,917 by Fugii, 3,757,495 by Sievers, 3,750,370 by Brauss, 3,745,750 by Arff, 3,744,216 by Halloran, 3,674,421 by Decupper, 3,576,593 by Cicirello, and 5,185,015 by Searle. Patents directed toward the use of ultraviolet light as a germicide against bacteria in water or other liquids include U.S. Pat. Nos. 4,400,270 by Hillman, 4,482,809 by Maarschalkerweerk, 5,102,450 by Stanley and 5,124,131 by Wekhof.
SUMMARY OF THE INVENTION
[0026] The present invention is an apparatus and process for destroying airborne pathogenic bacteria such as the tuberculosis bacteria. Ultraviolet lights of a sufficient intensity are positioned within a sterilization chamber where they irradiate an air stream containing the bacteria, typically in the form of suspended microdroplets of sputum. The sterilization chamber has an exit and an entrance, and a blower is positioned preferably at the exit to draw air into the entrance and through the sterilization chamber and out the exit. The air circulates behind an intake baffle and into the sterilization chamber having a set of ultraviolet lights. An outlet baffle at the opposite side of the sterilization chamber bounces the air that passes the ultraviolet lights back over the ultraviolet lights a second time, and around the outlet baffle to the fan. The fan then expels the sterilized air back into the room. The air passing through the sterilization chamber is virtually completely sterilized of viable tuberculosis bacteria by the chosen dosimetry of the system, which is achieved by appropriately sizing the sterilization chamber employing ultraviolet lights of the correct intensity, and utilizing the right air flow rate through the blower. The apparatus is configured to, fit behind a wall in a room, or preferably, above a suspended ceiling. Air is drawn by a fan from the room into an intake duct and into the apparatus.
[0027] The sterilization chamber includes a filter on the intake side to filter out large particles such as dust, in order to minimize the contamination of the ultraviolet light bulbs. The filter is deliberately designed not to intercept small particles such as microdroplets, since the filter could then become a bacteria colony. The use of a low density filter also minimizes the resistance to air flow, thereby allowing the use of a smaller, more efficient and quieter blower. With the exception of this intake filter for removing large particulates, the apparatus preferably does not include any devices that would intercept and retain microdroplets or other small particles in a way that resists the air flow and poses the possibility of becoming a bacteria colonization site; the small particulates and microdroplets with destroyed bacteria simply pass through the apparatus and are expelled back into the environment.
[0028] Both the air intake and exhaust to the sterilization chamber are baffled so that ultraviolet light must reflect off multiple surfaces before exiting the sterilization chamber. The interior surfaces of the baffles may be light-absorptive to minimize their reflectivity and further lessen the possibility of ultraviolet light leaking from the sterilization chamber into the environment.
[0029] The apparatus is used in a space having a volume of air that results in an air exchange rate of preferably 12-15 air exchanges per hour. At that air exchange rate, it has been determined that a sufficient volume of air will circulate through the apparatus and will prevent any air stagnation in the room, that a high enough percentage of tuberculosis bacteria will be destroyed before they are inhaled by persons in the room to prevent transmission of the disease.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] [0030]FIG. 1 is a pictorial cutaway view of the present invention.
[0031] [0031]FIG. 2 is a side sectional view of the present invention, taken along line 2 - 2 of FIG. 1, installed in a suspended ceiling.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] A pictorial view of a preferred embodiment of the invention is shown in FIG. 1. The principal elements of the invention 10 include an exterior housing 40 having an air intake duct 42 and an air discharge duct 44 , a squirrel-cage type blower 120 and set of ultraviolet lights 150 in a sterilization chamber 180 within the housing 40 . The air intake duct 42 is preferably positioned at one end 46 of the housing and the air discharge duct 44 is positioned at the opposite end 47 of the housing 40 .
[0033] As better shown in the sectional view of FIG. 2, the air intake duct 42 has positioned within it a filter 60 which substantially fills the intake duct 42 so that all air drawn through the air intake duct 42 must pass through the filter 60 . The filter 60 is preferably not a high-density filter, but is instead designed to intercept and retain only fairly large particulates such as dust. The purpose of the filter 60 is not to allow the apparatus 10 to purify the air, but is merely to intercept dust over 10 microns in size that would otherwise contaminate the ultraviolet light bulbs 150 . In a preferred embodiment, the filter is model no. DP1-40, available from Airguard Industries located in Louisville, Ky. The filter 60 is retained in the air intake duct 42 by means of clips, brackets or any other suitable retention means (not shown) that allow easy removal and replacement of the filter 60 .
[0034] It is notable that in the preferred embodiment, there is no filter at all in the air discharge duct 44 or elsewhere downstream from the sterilization chamber. Therefore, the only filter in the preferred embodiment is the large particulate filter 60 positioned in the air intake duct 42 . The apparatus 10 is designed to allow small particulates, including microdroplets of sputum containing bacteria that are destroyed by the ultraviolet lights as described below, to be expelled back into the environment. As a result, the apparatus does not have a site that traps and allows the colonization of bacteria, which would require frequent cleaning or sterilization. In addition, there is very little resistance to air flow, thereby allowing the use of a relatively small, low-energy and quiet motor and blower system, as further described below.
[0035] In this respect, the present system is fundamentally different from prior art devices that are designed to remove dirt, pollen and other particulates and odor from the air. Those prior art systems employ dense and multiple filters and noisy high-energy blowers to indiscriminately remove impurities from the air. But they are not specifically for the purpose of destroying pathogenic pulmonary bacteria such as tuberculosis and their efficiency in doing so is undocumented and questionable. In contrast, the present system is specifically designed for destroying bacteria such as the tuberculosis bacteria, and is highly effective in accomplishing that using a relatively small, energy efficient, quiet apparatus, but the present system makes no attempt at all to remove impurities from the air. Even the bacteria itself is released back to the environment once it is killed by the apparatus.
[0036] The air discharge duct 44 is preferably positioned remotely from the air intake duct 42 , so that the exhausted air circulates into the environment rather than being immediately drawn back into the apparatus 10 . In the embodiment shown in FIGS. 1 and 2, the positioning of the ducts 42 and 44 on opposite ends of the housing produces a circulatory effect through the environment of the apparatus 10 by drawing air into the apparatus 10 through the air intake duct 42 and expelling air from the apparatus 10 through the air discharge duct 44 , roughly in the direction of the arrows shown in FIG. 2. The air discharge duct 44 may be covered with a grill (not shown) to prevent the introduction of hands or objects into the air discharge duct 44 and to diffuse the air stream exhausted from there. A door 183 is positioned in the bottom of the housing 40 as shown in FIG. 2 and is attached to the housing 40 by a hinge 185 or other suitable attachment means. The door is positioned to allow ready access to the ultraviolet lights 150 and to the filter 60 to allow them to be changed or cleaned.
[0037] The sterilization chamber 180 is baffled on the upstream side by an intake baffle 182 , and on the downstream side by a pair of exhaust baffles 184 and 187 , to prevent ultraviolet light from leaking from the sterilization chamber 180 out the air intake duct 42 or air discharge duct 44 and into the environment where it could damage the skin and eyes of patients and other persons. The baffles also improve the circulation of the air over the ultraviolet bulbs in the manner described below. The intake baffle 182 in the preferred embodiment is an S-shaped element fabricated from sheet metal or other appropriate material that is not degraded by ultraviolet light. The lower portion of the intake baffle 182 is curved away from the air intake duct 42 to receive the incoming air, while the upper portion of the intake baffle 182 is curved toward the sterilization chamber 180 to allow the incoming air to flow smoothly over the top of the intake baffle 182 and into the sterilization chamber 180 . The intake baffle 182 may be attached to the housing 40 at the bottom of the intake baffle 182 or at the ends.
[0038] The exhaust baffles 184 and 187 form a channel therebetween for the air to leave the sterilization chamber 180 , as best shown in the sectional view of FIG. 2. Both exhaust baffles 184 and 187 are curved with the inner side of the curve away from the sterilization chamber 180 . The air passes under the lower edge of the upper exhaust baffle 184 , through the channel defined by the upper baffle 184 and 187 , and over the upper edge of the lower exhaust baffle 187 .
[0039] The upper exhaust baffle 184 may be attached to the housing 40 at the top of the upper exhaust baffle 184 or at the ends. The lower exhaust baffle 187 may be attached to the housing 40 at the bottom of the lower exhaust baffle 187 or at the ends.
[0040] It can be appreciated that for any ultraviolet light to escape from the sterilization chamber 180 through the air discharge duct 44 , it must reflect off the walls of the sterilization chamber 180 , reflect through the channel defined by the upper and lower exhaust baffles 184 and 187 , and then through the blower 120 and out the air discharge duct 44 . For any ultraviolet light to escape through the air intake duct 42 , it must reflect off the walls of the sterilization chamber 180 , into the space between the air intake duct 42 and the intake baffle 182 , through the air intake filter 60 and through the air intake duct 42 . The possibility of light escaping can be further reduced by applying an absorptive coating or paint to the interior surfaces of the baffles 182 , 184 and 187 and the other interior surfaces of the housing 40 .
[0041] Although the baffling described above to prevent ultraviolet light from escaping presents a circuitous route for the passage of air from the air intake duct 42 through the sterilization chamber 180 and out the air discharge duct 44 , the baffles are still designed to minimize the resistance to air flow. Thus, as shown by the arrows in FIG. 2, the air can flow reasonably smoothly with limited turbulence loses, thereby allowing a small, quiet and efficient blower system.
[0042] An important aspect of the embodiment shown in FIGS. 1 and 2 is that the baffles 182 and 184 and sterilization chamber 180 are configured such that the air passes the ultraviolet lights twice. As shown by the arrows of FIG. 2, the air passes the ultraviolet lights a first time immediately after it passes over the top of the air intake baffle 182 and into the sterilization chamber. The air pathway is blocked on the opposite side of the sterilization chamber by the air exhaust baffle 184 . The inclined and curved surface of the air exhaust baffle, together with the top wall of the housing 40 , define a space 186 to receive the air after it passes the ultraviolet light a first time. The air then reflects off the air exhaust baffle 184 and out of the space 186 and back toward the ultraviolet lights for a second pass. The air is then drawn out of the sterilization chamber 180 by passing under the exhaust baffle 184 and into the blower 120 .
[0043] The blower 120 in the preferred embodiment is of the “squirrel-cage” type. The blower 120 draws air through its ends and propels the air out the middle and into the exhaust duct 44 . The exact size of the blower and the motor for the blower depend on the desired use of the machine and the size of the environment in which it will be used, as further discussed below. The motor is preferably of the normal alternating current type and is in communication with the electrical system (not shown) of the apparatus, which also powers the ballasts for the ultraviolet lights 152 . The electrical system is ordinary, and the details of it will be apparent to those skilled in the wiring of lights and motors and it is not further described herein.
[0044] The apparatus 10 is preferably positioned in the suspended ceiling 191 of a patient room as shown in a preferred arrangement in FIG. 2. Cutouts in the ceiling 191 are provided for the air intake duct 42 , air discharge duct 44 and access door 183 . The microdroplets from the patient are expectorated from the patient into the surrounding air where they are suspended. The air currents produced by the apparatus 10 draws air into the apparatus 10 from intake duct 42 . The filter 60 traps large dust particles, but allows small particles to pass including the micro droplets of small bacteria-containing sputum. The air with the suspended microdroplets passes through the sterilization chamber where the bacteria are destroyed by passing twice over the ultraviolet lights, and the air along with the suspended microdroplets with the then-killed bacteria are expelled from the apparatus 10 back into the room through the air discharge duct 44 . Because the air discharge duct 44 is preferably positioned at one end 46 of the apparatus 10 while the air intake duct 42 is positioned at the other end 47 of the apparatus, the air being drawn into the air intake duct 42 and expelled from the air discharge duct 44 produces a circulatory effect through the room which increases the flow of new unsterilized air into the apparatus. This circulatory effect also helps prevent the air from short-circuiting the circulation pattern by leaving the apparatus 10 through the air discharge duct 44 and immediately re-entering the apparatus 10 through the air intake duct 42 without passing through the room.
[0045] It has been determined experimentally that transmission of the tuberculosis bacteria from an infected patient to an uninfected person can be effectively prevented by ensuring that there are approximately 10 to 15 air changes per hour in the patient room using the apparatus and positioning described above. The phrase “10 to 15 air changes per hour” means a circulatory effect through the apparatus in which the total volume of air through the apparatus per hour equals the air volume of the room multiplied times a number between 10 and 15, inclusive. For example, one air change per hour in a 1,000 cubic foot room would require an apparatus through which 1,000 cubic feet of air pass per hour. Therefore, in a patient room having dimensions of 10 by 10 by 10 feet for a total volume of 1,000 cubic feet, or other dimensions for a total volume of 1,000 cubic feet, the apparatus should be capable of circulating through it at the rate of 10,000 to 15,000 cubic feet of air per hour.
[0046] The exact dimensions of the apparatus to achieve such a flow rate in a preferred embodiment include a housing 40 having a length of about 48 inches, a height of about 15.5 inches, and a depth of about 36 inches.
[0047] The air intake duct 42 is roughly 6 inches by 24 inches and the air discharge duct 44 is roughly 6 inches by 18 inches. The opening between the top of the air intake baffle 182 and the housing 40 is about 4 inches, and the opening between the bottom of the air exhaust baffle 184 and the housing 40 is about 4 inches. The motor is a 115 volt, 1,725 rpm motor, and the blower 120 includes 4 by 9 inch blower wheels. The ultraviolet lights 152 are model D-36-3 by American U. V. Co.
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A germicidal method and apparatus for destroying airborne pathogenic bacteria such as tuberculosis bacteria using ultraviolet light. Air is drawn through a filter and into a sterilization chamber that is irradiated with ultraviolet light, and out through an exhaust opening. Consideration for the characteristics of the room in which the apparatus is installed and the positioning of the installation allows effective prevention of transmission of disease through expectoration and inhalation of airborne microdroplets of bacteria-containing sputum. The filter is of the low-density type which traps large particulates, but not small particulates of the size of the microdroplets, so that the filter does not become a bacteria colonization site. Baffles on the air intake opening and air exhaust opening to prevent ultraviolet light from escaping into the environment. The sterilization chamber is constructed such that the air passes the ultraviolet light bulbs twice as it circulates therethrough.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an anchor for tying a masonry veneer wall to the framing of an architectural structure.
2. Description of the Prior Art
With modern construction techniques, it is a common practice to enclose the framing of a building with a masonry veneer wall.
Many architects and engineers firmly believe that masonry wall cracking would be reduced to a minimum if walls were permitted more freedom of movement. Accordingly, systems have been heretofore designed to provide lateral restraint while permitting horizontal and vertical movement.
In one form of such system heretofore manufactured and sold by the applicant's assignee, AA Wire Products Company of Chicago, Ill., a flexible tie for tying masonry walls to concrete or to steel is provided which is sold under the trademark "DOVETAIL FLEX-O-LOK" (to concrete) and "FLEX-O-LOK" (to steel). Examples of such ties include a masonry wall laterally tied to concrete or steel columns, or masonry walls laterally tied to concrete or steel beams, or precast concrete panels or stone laterally tied to poured concrete or steel back-up. In such an arrangement, a wire form or flat steel form of anchor is fastened either to an intervening flat plate or directly to an architectural structure as a matter of customer choice, whereupon a tying member adjustably moves relative to the anchor and is inserted between courses of the adjoining veneer wall, thereby to permit the desired flexibility.
The prior art is also exemplified by the Schwalberg U.S. Pat. No. 4,021,990 issued May 10, 1977 wherein a veneer anchor comprises a plate member having a vertically projecting bar portion secured thereto and disposed in substantially parallel relationship with the plate member. The anchor is employed to secure a wallboard to a vertical channel or standard framing member. Thereafter, a mason inserts a wall tie between the plate member and projecting bar portion and the wall tie is built into the outer wythe of the wall system. Since the wall tie is capable of vertical movement, vertical adjustability is effected.
To ensure structural stability and to resist lateral pressure, such as that resulting from wind forces, it is necessary to tie the masonry veneer wall to the framing. Furthermore, it is often desirable to maintain a gap between the framing and veneer wall for ventilation and drainage purposes or to accommodate a layer of insulating material.
The prior art structures do not accomplish such objectives with full effectiveness.
SUMMARY OF THE INVENTION
According to the present invention, an anchor is formed of an integral metal form which is preformed as an L-shaped bar such as an angle iron. The outstanding leg of the anchor has one or more slotted holes formed therein in a selected spaced relation depending on the end use. The leg overlying the building frame member is provided with holes through which fasteners, such as screws or nails, are inserted for securing the anchor to either metal or wood studs.
The depth of the outstanding leg and the spacing of the slotted openings is selectively varied to allow a desired thickness of insulating material to be placed in the gap between the framing and the veneer wall. The relative thinness of the outstanding anchor leg allows adjacent pieces of insulating material to be placed within close proximity of one another, thus minimizing energy-losing holes in the insulation.
A wire tie is inserted through one of the slotted holes in the anchor and is vertically adjustable to be embedded in a horizontal masonry joint. The wire may bear against the perimeter of the slotted hole. By virtue of such provision the present invention provides improved resistance to compressive as well as axial forces, thereby maximizing its functional effectiveness.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary perspective view of a masonry veneer wall construction incorporating a wall with insulation and embodying the principles of the invention;
FIG. 2 is a perspective view of the wall anchor used in the environment of FIG. 1;
FIG. 3 is a top plan view taken along the line III--III of FIG. 1;
FIG. 4 is a side sectional view taken along the line IV--IV of FIG. 1;
FIG. 5 is a perspective fragmentary view of a masonry veneer wall construction wherein the wall anchor of the present invention is used with a different form of wall construction utilizing metal studs and no insulation;
FIG. 6 is a top view taken along the line VI--VI of FIG. 5;
FIG. 7 is a side sectional view of a masonry veneer wall construction incorporating the anchor of the invention as used with a so-called weeper tie; and
FIG. 8 is a top sectional view taken along the line VIII--VIII of FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1, an insulated wall construction denoted generally at W, comprises a masonry veneer M, wood stud framing F, and a layer of insulation I. A wall anchoring means for tying the masonry veneer to the framing F embodying the principles of the present invention is shown generally at A.
According to the invention, the anchoring means A comprises a metallic member shaped as a prefabricated metal form, for example, an L-shaped metallic bar, with two legs perpendicularly offset with respect to one another comparable to an angle iron. Thus, as best shown in FIG. 2, there is provided a first leg 12 having a longitudinal edge 13 and opposite end edges 14 and 16. The leg 12 is intended to lie against a corresponding framing member, whether that framing member be wood, steel or concrete. In order to affix the leg 12 to an adjoining surface of a framing member, there is provided a pair of spaced through holes 17 and 18 located inwardly of the end edges 14 and 16, respectively.
A second leg 19 is offset perpendicularly with respect to the leg 12 and is provided with a longitudinal edge 20 and opposite end edges 21 and 22.
In the form of the invention illustrated in FIG. 1, the leg 19 of the anchoring means A is selected to be of a length sufficient to extend completely through the insulation I and to locate the edge 20 adjacent the inner surface of the veneer M.
It is contemplated by the present invention that there be provided in the leg 19 one or more elongated recesses or openings to accommodate an adjustable tie. Accordingly, there is shown in the drawings, by way of example, two separate slots or elongated openings which are indicated at 26 and 27, respectively, the slots 26 and 27 being located inwardly of the edge 20 and bounded longitudinally by ends 28 and 29 and laterally by sides 33 and 34 with respect to the slot 26, and bounded by the ends 30 and 31 and the sides 35 and 36 with respect to the slot 27. The extreme ends 28 and 31 are inwardly of the edges 21 and 22, respectively, and the inner ends 29 and 30 are spaced from one another and separated by a continuous web portion of the leg 19 shown specifically at 32. In practical effect, therefore, the limits of adjustability are prescribed by the ends of the two slots, namely, the extreme ends 28 and 31. Preferably, the slots 26 and 27 are arranged in a coaxial disposition with respect to one another, although it is conceivable that the slots could be located on different axes and the anchor would still be functional. Generally, the slots are disposed in parallelism to the main longitudinal axis of the anchor.
With respect to the anchoring means A, as shown in FIGS. 1-4, it will be apparent that the slots 26 and 27 are located inwardly of the edge 20 but are spaced so that the slots will extend outwardly of the insulation I, permitting ready access to slots 26 and 27 for accommodation of a tie member designed to provide lateral restraint while permitting horizontal and vertical movement.
It is contemplated by the present invention that the depth of the leg 19 be selectively varied so that the anchoring means A could be provided in specifically selected sizes for different end use applications. Thus, the selectively variable dimension would be the dimension between the corner joint 23 and the slot inner sides 34 and 36 which dimension is shown in FIG. 2 at 24. As an example of how the width of the outstanding leg 19 may be selected to accommodate intervening layers of insulating material of various thicknesses, it may be noted that to accommodate a one inch (25.4 mm) thick insulation layer, the dimension 24 may be set at 11/8 inch (28.6 mm). To accommodate a two inch (50.8 mm) thick insulation layer, the dimension 24 may be set at 21/8 inch (54.0 mm).
In order to effect flexible anchorage and wall clamping, ties shown generally at 40 are provided which may conveniently be formed in varied sizes. For example, 3/16" mill galvanized wire is provided in a truncated triangular configuration. Nos. 9 or 6 gauge or 1/4" is also selectively available.
As best shown in FIG. 3, the wire form tie member has angled side legs 41 and 42 meeting at an apical portion truncated to form an end leg 43. There are two base legs 44 and 45 separated by a gap 46 to permit the tie 40 to be inserted into the slots of the anchor. The ties vary from 3" to 9" in depth to accommodate veneer walls of different thickness.
Layers of insulating material I are interposed between the veneer wall and the framing C. The pieces of insulating material may be brought together so that they are separated only by the thickness of the outstanding leg 19 of the anchor A. If the edges of the insulation are notched to fit around the outstanding leg 19, the insulation may be abutted. With either approach, minimal energy losing air gaps in the insulation may be achieved.
The end leg side 43 of the tie 40 serves to confine the insulating material I and maintain an air gap G between the masonry veneer M and the insulation I.
As best seen on FIG. 4, the length of a slotted hole, or, as in this exemplary embodiment, the combined lengths of the slotted holes 26 and 27 should be somewhat greater than the thickness of a course of brick or block B. This will provide an adequate range of vertical adjustment of the tie 40 so that the tie 40 may rest atop a brick or block B regardless of the placement of the anchor A along the stud C.
It is also possible to apply the anchor of the invention in a wall construction incorporating a layer of wallboard. The wallboard may be interposed between the stud C and the anchor A with fasteners such as nails 50 and 51 driven through the holes 17 and 18 and wallboard into the stud C.
In the form of the invention shown in FIGS. 5 through 8, the anchor A is connected to a metal stud D and is used to lock a veneer M without an insulation layer. Thus, the leg 19a is provided with a structural configuration of comparable characteristics each denoted by a comparable reference numeral, but with a suffix "a".
The slot or slots 26a and 27a, are in effect, located at a lesser depth since the insulation layer need not be accommodated.
Referring to FIG. 5, the anchoring means of the invention is shown as incorporated in a non-insulated wall construction. The anchoring means A is similar in all respects to the embodiment shown in FIGS. 1 through 4, except that the width or depth or the outstanding leg 19a is smaller or shallower. This embodiment is suitable for use in wall constructions where no layer of insulation or other material is desired between the stud D and the masonry M.
This embodiment of the anchor A is shown in FIG. 5 as being used with a metal stud D. As best seen in FIG. 6, the anchor may be attached to the stud D by a fastener such as a rivet or a sheet metal screw 36.
In the form of the invention shown in FIGS. 7 and 8, the anchor A is connected to a stud D or a wall and is used to lock a veneer M by means of a so-called weeper tie. The tie 37 is formed of a bent wire and is generally rectangular having a gap 38 in one of the shorter sides 39. There are two downward bends 47 and 48 formed in the longer sides of the tie 37 intended to cause accumulated moisture to fall within the air space between the masonry D thus preventing wetting of wall surfaces.
It should be appreciated that alternative designs of ties such as tie 37 and 40 may be used interchangeably with the various embodiments of the anchor of the invention, such as the anchors shown in FIGS. 1 through 4 and in FIGS. 5 through 8.
It may be seen that compressive forces against the wall will be transmitted by the wire tie to an inner edge 34 or 36 (as shown in FIG. 2) of the slots 26 or 27 and then through the outstanding leg 19 ultimately distributing the load to the framing over the entire area of the overlying leg 12. Thus, both pushing and pulling forces such as those developed by wind pressures are effectively resisted.
As is now apparent, a new and useful masonry veneer wall anchor is provided, capable of accommodating a layer of insulating material and resisting pulling or pushing forces.
Although modifications might be suggested by those skilled in the art, it will be understood that I wish to embody within the scope of the patent described herein all such modifications as reasonably and properly come within the scope of my contribution to the art.
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A masonry veneer wall anchor formed of an integral metal form preformed as an L-shaped bar has one leg overlying a building frame member for attachment thereto and has an outstanding leg with slotted holes formed therein in selected spaced relation through which a tying member may be inserted for vertical adjustment, the tying member engaging the edges of the slot to provide improved resistance to compressive as well as pulling forces, thereby maximizing functional effectiveness.
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BACKGROUND
Technical Field
The present disclosure concerns in general resonant switching converters circuits and in particular a control method of a resonant dc-dc converter aimed to optimize conversion efficiency (i.e., the ratio between the power provided to the load and that drawn from the input source) at low load, and a circuital implementation thereof, preferably realized in integrated form.
Description of the Related Art
Resonant converters represent a broad class of switching converters and include a resonant circuit playing an active role in determining the input-output power flow. In these converters, a bridge (half-bridge) consisting of four (or two) power switches (typically power MOSFETs) supplied by a dc voltage generates a square voltage wave that is applied to a resonant circuit (also termed resonant tank) tuned to a frequency close to the fundamental frequency of the square wave. Because of its selective response, the resonant circuit mainly responds to the fundamental component and negligibly to the higher order harmonics of the square wave. As a result, the circulating power may be modulated by varying the frequency of the square wave, holding the duty cycle constant at 50%. Moreover, depending on the resonant circuit configuration, the currents and/or voltages associated with the power flow have a sinusoidal or piecewise sinusoidal shape.
These voltages and/or currents are rectified and filtered so as to provide DC power to the load. In offline applications (i.e., those operated from the power line), the rectification and filtering system supplying the load is coupled to the resonant tank circuit by means of a transformer providing galvanic isolation between the source and the load, to comply with safety regulations. As in every isolated dc-dc converters, also in this case a distinction is made between a primary side (as related to the primary winding of the transformer) connected to the input source and a secondary side (as related to the secondary winding(s) of the transformer) providing power to the load through the rectification and filtering system.
As an example of resonant converter, FIG. 1 shows the so-called LLC resonant converter, probably today's most widely used resonant converter, especially in its half-bridge version. The designation LLC stems from the fact that the resonant tank employs two inductors (L) and a capacitor (C).
The resonant converter comprises a “totem-pole” of transistors M 1 and M 2 connected between the input voltage source node Vin and ground GND, controlled by a control circuit. The common terminal HB between the transistors M 1 and M 2 is connected to a resonant tank comprising a series of a capacitor Cr, an inductance Ls and another inductance Lp connected in parallel to a transformer with a center-tap secondary winding. The two windings of the center-tap secondary are connected to the anodes of two diodes D 1 and D 2 , whose cathodes are both connected to the parallel of a capacitor Cout and a resistance Rout; the output voltage Vout of the resonant converter is across said parallel while the DC output current Iout flows through Rout.
Resonant converters offer considerable advantages as compared to traditional switching converters (which are not resonant, but typically PWM—Pulse Width Modulation—controlled): waveforms without steep edges, low switching losses in the power switches due to their soft-switching operation, high conversion efficiency (>95% is easily reachable), ability to operate at high frequencies, low EMI generation (Electro-Magnetic Interference). All these features make resonant converters ideal candidates when high power density is to be achieved, that is, when conversion systems capable of handling considerable power levels in a relatively small space are preferred.
As in most DC-DC converters, the output voltage is kept constant against changes in the operating conditions (i.e., the input voltage Vin and the output current Iout) through a control system that uses closed-loop negative feedback. As shown in the block diagram of FIG. 2 , this is achieved by comparing a portion of the output voltage Vout to a reference voltage Vref, their difference (error signal) is amplified by an error amplifier whose output Vc (control voltage) is transferred to the primary side across the isolation boundary typically via an optocoupler. The optocoupler changes the control voltage Vc into a control current I FB . Note that normally the circuit arrangement comprising the error amplifier and the optocoupler is such that the control voltage Vc and the control current I FB change in opposite directions: if Vc increases I FB decreases, if Vc decreases, I FB increases. The control current I FB modifies a quantity X within the converter which the power carried by the converter substantially depends on.
In resonant converters, as mentioned earlier, this significant quantity is the switching frequency of the square wave stimulating the resonant tank (X=ƒ sw ). In nearly all practical resonant converters, if frequency rises the delivered power decreases and vice versa.
A consideration common to many applications of switching converters, resonant and not, is that conversion efficiency is maximized also under light load conditions to comply with regulations and recommendations on energy saving (e.g., EnergyStar, CEC, Eu CoC, Climate Savers, etc.).
A popular technique for optimizing light load efficiency in all switching converters (resonant and not) is to make them work in the so-called “burst-mode”. With this operating mode the converter works intermittently, with series (bursts) of switching cycles separated by time intervals during which the converter does not switch (idle time). When the load is such that the converter has just entered burst-mode operation, the idle time is short; as the load decreases, the duration of the bursts decreases as well and the idle time increases. In this way, the average switching frequency is considerably reduced and, consequently, so is the effect of the two major contributors to power losses at light load:
1) switching losses associated to the parasitic elements in the converter
2) conduction losses related to the flow of reactive current in the resonant tank (e.g., the magnetizing current in the transformer). In fact, this current only flows while the converter is switching and is essentially zero during the idle time.
The duration of the bursts and the idle time are determined by the feedback loop so that the output voltage of the converter always remains under control. To explain the mechanism governing this operation it is convenient to refer to a concrete example.
FIG. 3 shows how burst-mode operation is implemented in the integrated control circuit L 6599 by STMicroelectronics, as well as a simplified schematic of its internal current-controlled oscillator (CCO). FIG. 4 shows the oscillator waveform of the CCO, its relationship with the gate drive signals for M 1 and M 2 produced by the pulse-train generator and the voltage of the half-bridge midpoint HB, i.e., the square wave voltage applied to the resonant tank.
The CCO is programmed by means of the capacitor C 1 connected from pin CF to ground and by the current I R sourced by the pin RFmin, which provides an accurate reference voltage Vr (=2 V). I R is internally mirrored and a current K M ·I R is alternately sourced and sunk from pin CF, originating a symmetrical triangular waveform included between a peak value (=3.9 V) and a valley value (=0.9 V) across C 1 . As a result, the higher the current I R , the faster C 1 is charged and discharged and the higher the oscillation and switching frequency (ƒ osc ) Denoting with ΔV osc the peak-to-valley swing of the oscillator (=3 V), the following relationship can be found:
f
osc
=
K
M
I
R
2
Δ
V
osc
C
1
The current I R is the sum of the current flowing through R 1 (=Vr/R 1 ) and the current I FB sunk by the phototransistor of the optocoupler OC that transfers the control voltage Vc across the isolation boundary. Therefore, the current I FB actually modulates I R , closing the feedback loop that regulates the output voltage of the converter and making it work at a frequency given by:
f
sw
=
f
osc
=
K
M
2
Δ
V
osc
C
1
(
Vr
R
1
+
I
FB
)
.
Note that this is done consistently with the relationship that links the delivered power to frequency in the resonant converter and the configuration of the feedback circuit. In fact, when the load demands less power, the output voltage tends to increase; the feedback loop reacts by reducing the control voltage Vc, which increases the OC current I FB , and, therefore, the switching frequency as well, thus reducing the delivered power and counteracting the output voltage rise.
The timing components R 1 , R 2 and C 1 define the oscillation frequency range of the CCO. In particular, R 1 sets the minimum operating frequency, which occurs when the current I FB is zero:
f
sw
·
min
=
f
osc
·
min
=
K
M
Vr
2
Δ
V
osc
R
1
C
1
.
R 2 along with R 1 sets the maximum operating frequency, that is, the frequency at which the device enters burst-mode operation, in which the device operates in short bursts, separated by idle periods. In fact, when I FB is such that the voltage on pin STBY, V STBY , is lower than the threshold voltage V th , the output of the comparator CO 1 goes high and inhibits the oscillator and the pulse-train generator, causing both switches M 1 and M 2 to stay off. This frequency is given by:
f
sw
·
max
=
f
osc
·
max
=
K
M
2
Δ
V
osc
C
1
(
Vr
R
1
+
Vr
-
V
th
R
2
)
.
Therefore, there is a discontinuity in the ƒ osc vs. I FB relationship, so that its complete expression is:
f
sw
=
f
osc
=
{
K
M
2
Δ
V
osc
C
1
(
Vr
R
1
+
I
FB
)
if
I
FB
≤
Vr
-
V
th
R
2
0
otherwise
.
(
1
)
With the aid of FIG. 5 it is possible to explain burst-mode operation as follows.
When the load decreases (and the switching frequency rises) to the point that V STBY falls below the threshold V th , the converter stops switching and the idle time begins. Since no more energy is delivered during the idle time, the load is supplied only by the filtering system (normally, the output capacitor bank Cout shown in FIG. 1 , which here acts as energy reservoir as well) and the output voltage starts decaying. The feedback loop reacts to this by increasing the control voltage Vc, so I FB decreases and V STBY rises; as V STBY exceeds V th by a quantity equal to the hysteresis V H of the comparator CO 1 , the output thereof goes low thus re-enabling the oscillator and the pulse-train generator. M 1 and M 2 restart switching and the idle time ends. Due to this, the output voltage increases and, consequently, Vc decreases, I FB increases and V STBY decreases: as soon as it falls again below V th the converter stops switching again, and so on.
Note that the oscillator frequency at the beginning of a burst, ƒ osc.bb , is slightly lower than ƒ osc.max , in fact:
f
osc
·
bb
=
K
M
2
Δ
V
osc
C
1
[
Vr
R
1
+
Vr
-
(
V
th
-
V
H
)
R
2
]
=
f
osc
·
max
-
K
M
V
H
2
Δ
V
osc
R
2
C
1
.
(
2
)
BRIEF SUMMARY
The performance of the above illustrated technique is rather good and the benefit in terms of efficiency improvement significant. However, the efficiency targets set by the upcoming regulations and recommendations concerning energy saving are becoming more and more demanding and it is tough to meet them even with resonant converters and their present day burst-mode control techniques. As a matter of fact, substantially all the control devices for resonant converters commercially available have a burst-mode operation that, apart from some minor details not concerning efficiency optimization, works in the way illustrated above.
There is a demand for a new and more efficient burst-mode technique that would make easier to meet these new challenging targets. Many studies on this topic are ongoing, a review of which is provided by the appended list of references.
In [1], a new technique is proposed where the “burst duty cycle”, intended as the ratio of the duration of a burst to their repetition period, is changed depending on the output current Iout, while the switching frequency is kept constant within each burst. This technique cannot be easily used in systems where the control device is located on the primary side because the information coming from the output current sensing circuit has to cross the isolation boundary. Additionally, in [1] the usage of an MCU is proposed, which limits the applicability of the method to high-end systems where cost is not a prime concern.
In [2] a hysteretic (in the end, synonymous with burst-mode) control scheme is proposed where the converter always operates at the resonance frequency of the resonant tank and the low-side MOSFET M 2 is kept always on during the idle time. This technique is simple but has the drawback of depleting the energy in the resonant tank completely. When a burst starts, the energetic state of the resonant tank has to be restored, similarly to a start-up condition but without high frequency operation that limits circulating currents. Big currents, large output voltage ripple and audible noise are expected.
In [3] a novel LLC burst mode control with a constant duration of the bursts and optimal switching pattern is proposed. The duration of bursts is constant, while the idle time is modulated by load conditions. In each burst, a three pulse switching pattern is implemented to keep output voltage low frequency ripple at a minimum. Also in this case the usage of an MCU is proposed, which brings the same limitations mentioned earlier.
In [4] a method is proposed in which the converter operates below the resonance frequency of the resonant tank during burst-mode, which seems to be quite a design limitation.
According to an embodiment described in the present disclosure a new and more efficient burst-mode technique is provided, as compared to those discussed above, that, on one hand, provides a substantially improved efficiency with limited drawbacks in terms of output voltage ripple increase and audible noise, and, on the other hand, lends itself to a relatively simple and low-cost circuit implementation.
According to another embodiment, a circuital implementation of the new and more efficient burst-mode method is disclosed, preferably to be realized in integrated form on a silicon chip. According to a further embodiment, a control device for resonant converters is disclosed, embedding the aforesaid circuit and a resonant converter controlled by the control device.
According to an embodiment, a method for controlling operation of a resonant converter is provided, including controlling a switching frequency of the converter, and thereby its power output, in direct relation to a feedback current, shifting the converter to an idle condition when the feedback current exceeds a first threshold, and introducing a nonlinearity into the relation of the switching frequency and the feedback current when the current exceeds a second threshold, lower than the first threshold.
According to another embodiment, a device for controlling a resonant converter is provided, that includes a current controlled oscillator having an input configured to receive a feedback control current from the controller and an output configured to provide a switching control signal for the converter, at a frequency that is related to a value of the feedback control signal current. The device also includes a burst mode control circuit configured to introduce a nonlinearity into the relation of the switching control signal frequency and the feedback control signal current while the control signal current is greater than a first threshold, and to shift the current controlled oscillator to an idle condition while the feedback control signal current is greater than a second threshold, higher than the first threshold.
According to an embodiment, the burst mode control circuit is configured the prevent the frequency of the switching control signal from increasing while the feedback control signal current is greater than the first threshold.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 shows a known LLC resonant half-bridge converter as an example of resonant dc-dc converters that can be rendered more efficient by the method of this disclosure.
FIG. 2 shows a block diagram illustrating a typical known example of output voltage regulation control loop in a resonant dc-dc converter such as that described with reference to FIG. 1 .
FIG. 3 shows the known current-controlled oscillator (CCO) in the commercial device L 6599 from STMicroelectronics as well as the circuit that implements the burst-mode operation.
FIG. 4 shows the triangular wave generated by the CCO of FIG. 3 , and its relationship with the gate-drive signals produced by the pulse-train generator.
FIG. 5 shows the key waveforms that illustrate burst-mode operation of the CCO of FIG. 3 , at light load.
FIGS. 6A-E show five possible examples of nonlinearity (“A”, “B”, “C”, “D”, “E”) in the ƒ osc (I FB ) function that, according to the applicant's findings, increase the energy transferred by a switching cycle of a resonant converter during burst-mode operation.
FIG. 7 shows an exemplary embodiment of a circuit that implements a nonlinearity of type “A” in the ƒ osc (I FB ) function.
FIG. 8 shows an exemplary embodiment of a circuit that implements a nonlinearity of type “B” in the ƒ osc (I FB ) function.
FIG. 9 shows an exemplary embodiment of a circuit that implements a nonlinearity of type “C” in the ƒ osc (I FB ) function.
FIG. 10 shows a first exemplary embodiment of a circuit that implements a nonlinearity of type “D” in the ƒ osc (I FB ) function.
FIG. 11 shows a second exemplary embodiment of a circuit that implements a nonlinearity of type “D” in the ƒ osc (I FB ) function.
FIG. 12 shows a third exemplary embodiment of a circuit that implements a nonlinearity of type “D” in the ƒ osc (I FB ) function.
FIG. 13 shows a first exemplary embodiment of a circuit that implements a nonlinearity of type “E” in the ƒ osc (I FB ) function.
FIG. 14 shows a second exemplary embodiment of a circuit that implements a nonlinearity of type “E” in the ƒ osc (I FB ) function.
FIG. 15 shows a third exemplary embodiment of a circuit that implements a nonlinearity of type “E” in the ƒ osc (I FB ) function.
FIG. 16 shows an external circuit that used for testing purposes, to implement a nonlinearity of type “C” in the ƒ osc (I FB ) function of STMicroelectronics resonant converter controller L 6599 .
FIG. 17 shows evaluation data of the light-load efficiency observed in a 90 W LLC resonant converter based on STMicroelectronics controller L 6599 with the external circuit of FIG. 16 , as compared to the same controller in a conventional circuit.
FIG. 18 are oscilloscope screen shots showing that the increase in the output voltage ripple caused by the circuit in FIG. 16 is acceptably low.
DETAILED DESCRIPTION
As mentioned earlier, the effectiveness of burst-mode operation in increasing light load efficiency stems from the reduction of the average switching frequency, which leads to a reduction of the switching losses associated to the parasitic elements in the converter and of the conduction losses associated to the reactive currents flowing in the resonant tank.
Therefore, to optimize efficiency during burst-mode operation, the power demanded by the load should be provided while minimizing the average switching frequency or, in other words, the number of switching cycles the converter performs per second. This can be achieved by maximizing the energy carried by the converter in each cycle, so as to reduce the number of cycles over time.
Since in a resonant converter the power it delivers increases when the switching frequency is reduced, the energy per cycle will increase if during burst-mode the converter is forced to switch at a lower frequency. Therefore, with reference to the schematic in FIG. 3 , the principle behind embodiments described in the present disclosure is to introduce a nonlinearity in the ƒ osc (I FB ) function just prior to reaching the discontinuity at I FB =(Vr−V th )/R 2 . To achieve a lower switching frequency this nonlinearity should originate an interval (I FB .a−I FB .b) where either the function ƒ osc (I FB ) or its derivative dƒ osc /dI FB or both have a step discontinuity such that ƒ osc (I FB )≦ƒ osc (I FB .a) for I FB ε(I FB .a, I FB .b). I FB .a represents the point on the ƒ osc (I FB ) characteristic at which the nonlinearity begins, and I FB .b is the point on ƒ osc (I FB ) at which the circuit stops switching and enters idle time mode. Between the two points, although the current I FB continues to rise, the switching frequency ƒ osc does not, thus reducing the overall average switching frequency during burst mode operation.
When increasing the energy-per-cycle level in burst-mode, this can produce an increase of the ripple in the output voltage. A trade-off can be employed to increase the energy-per-cycle without unduly increasing the ripple.
An assumption that is done in the following discussion is that the current level I FB .bb=(Vr−V th −V H )/R 2 (refer to eq. (2)) at which the converter resumes switching is always ≧I FB .a.
FIGS. 6A-6E show five possible examples of nonlinearity meeting the above assumption and that lend well themselves to a simple circuit implementation. Nonlinearities “A” and “B” keep ƒ osc (I FB ) continuous and have a discontinuity in the derivative; nonlinearity “C” introduces a discontinuity in ƒ osc (I FB ) only; nonlinearities “D” and “E” introduce a discontinuity both in ƒ osc (I FB ) and its derivative. Nonlinearities “C” and “D” look almost identical. However, after the discontinuity, with the former the slope of ƒ osc (I FB ) is unchanged, whereas with the latter the slope of ƒ osc (I FB ) changes too. For small amplitude of the discontinuities, which is what happen in practice, they are actually nearly indistinguishable.
In the following discussion some practical implementations of the nonlinearities of FIGS. 6A-E will be shown. They all refer to an exemplary current controlled oscillator (CCO) structure similar to that depicted in FIG. 3 , including two current mirrors connected to a timing capacitor C 1 and wherein one or both mirrors are coupled, through other current mirrors in cascade, to a dedicated input pin of the oscillator in order to make possible that the charge and/or discharge current of the timing capacitor C 1 be proportional to a current (I r ) sunk through said dedicated input pin.
Of course, similar types of functionality can be realized starting from different oscillator structures, with appropriate modifications that, in view of present disclosure, will be obvious to the skilled artisan.
The circuit shown in FIG. 7 is an example of implementation of the nonlinearity “A,” employing a current controlled oscillator (CCO) 10 A, a burst mode control circuit 12 A, a comparator CO 1 , and a pulse-train generator 13 according to one embodiment. The CCO 10 A includes a first current mirror 14 , including transistors Q 2 , Q 3 , Q 4 , bias resistor R B , and an inhibit switch SW; and a second current mirror 16 , including transistors Q 5 , Q 6 , connected to a timing capacitor C 1 . The inhibit switch SW enables (when closed) the oscillator by connecting the first current mirror 14 to a first clamp circuit 18 , including op-amp OA 1 and transistor Q 1 , in order to make possible that the charge and/or discharge current of the timing capacitor C 1 be proportional to a current (I r ) sunk through said dedicated input pin. Also connected to the input pin RFmin are resistors R 1 , R 2 and the optocoupler OC. The CCO 10 A also includes comparators CO 2 , CO 3 , a flip-flop FF, and a transistor Q 7 coupled to the second current mirror 16 .
The burst mode control circuit 12 A includes a second clamp circuit 20 including an op-amp OA 2 and a transistor Q 8 coupled by another input pin STBY to the optocoupler OC; a current mirror 22 including transistors Q 9 , Q 10 ; a current mirror 24 including transistors Q 11 , Q 12 ; and a reference current source providing a reference current I ref .
As long as I FB <I FB .a (i.e., V STBY >V th ), where I FB .a=(Vr−V th )/R 2 , it is I R2 =I FB and I S =0. When I FB equals I FB .a (i.e., when V STBY =V th ), a second precision clamp circuit 20 made up of the op-amp OA 2 and transistor Q 8 is activated and prevents V STBY from further decreasing. Therefore, as the optocoupler OC sinks a current I FB >I FB .a the current through R 2 remains fixed at I FB .a, and the oscillator frequency at ƒ osc (I FB .a). The extra current I S =I FB −I FB .a is provided by the clamp circuit 20 , in particular by Q 8 . This current is mirrored by transistors Q 9 , Q 10 and compared to the reference current I ref mirrored by transistors Q 11 , Q 12 . As long as I S <I ref the collector of Q 11 is substantially at Vcesat and the output of the comparator CO 1 is low. When I S becomes larger than I ref , the Vce of Q 11 goes up and as it exceeds V th1 the output of CO 1 goes high and inhibits the oscillator through the switch SW and the pulse-train generator 13 . Note, incidentally, that I FB .b=I FB .a+I ref . Note also that the CCO is exactly the same as that shown in FIG. 3 .
The circuit shown in FIG. 8 is an example of implementation of the nonlinearity “B” employing a current controlled oscillator 10 B and a burst mode control circuit 12 B according to another embodiment. It can be thought as derived from the circuit in FIG. 7 with the addition of current mirrors 26 , 28 , 30 in the CCO 10 B and current mirrors 32 , 34 in the burst mode control circuit 12 B. The current mirror 26 includes transistors Q 3 , Q 4 , Q 15 , bias resistor R B , and inhibit switch SW, current mirror 28 includes transistors Q 14 , Q 16 , current mirror 30 includes transistors Q 2 , Q 13 , current mirror 32 includes transistors Q 9 , Q 10 , Q 17 , and current mirror 34 includes transistors Q 18 , Q 19 .
It works substantially in the same way as the circuit in FIG. 7 , except that the mirror 34 subtracts the current I S , sourced by Q 8 , from the current I R sourced by Q 1 and going from Q 13 to the mirror 28 . Thus, this mirror and the subsequent mirrors 16 , 26 in the chain, mirror I R −I S . As a result, the larger I S , the smaller the current KM·(I R −I S ) charging and discharging C 1 and, therefore, the lower ƒ osc (I FB )=ƒ osc (2I FB .a−I FB ).
I FB .a and I FB .b are the same as in the previous circuit. For simplicity, the mirrors 32 , 34 work with a 1:1 mirroring ratio; with a different mirroring ratio it is possible to change the slope of the ƒ osc (I FB ) characteristic in the region (I FB .a, I FB .b).
The circuit of FIG. 9 is an exemplary implementation of the nonlinearity “C” including a CCO 10 C and a burst mode control circuit 12 C according to an embodiment. The CCO is the same as that shown in FIG. 3 except for the addition of a switch SPDT 1 that is configured to switch the reference voltage on the non-inverting input of the op-amp OA 1 between Vr and a second value Vr r <Vr. The burst mode control circuit 12 C includes a comparator CO 4 having a non-inverting input coupled to the input pin STBY, an inverting input that receives the threshold voltage V th1 , and an output coupled to a control terminal of the switch SPDT 1 . Either reference voltage value is selected by the output of the comparator CO 4 : if the output is high (which occurs when I FB <I FB .a i.e., V STBY >V th1 , the single-pole double-throw switch SPDT 1 connects the non-inverting input of op-amp OA 1 to Vr, otherwise to Vr r .
As V STBY =V th1 and the output of CO 4 goes low, the resulting drop ΔVr=Vr−Vr r in the reference voltage for OA 1 determines the same drop ΔVr in the voltage appearing on the pin RFmin. As a consequence, also V STBY will drop by ΔVr since I FB is unchanged. If ΔVr≧V th1 −V th , V STBY will immediately fall below V th , which asserts the output of CO 1 high, thus inhibiting the oscillator through the switch SW, and the pulse-train generator. In this case it is substantially I FB .a=I FB .b=(Vr−V th1 )/R 2 . If, instead ΔVr<V th1 −V th , the frequency drop resulting from ΔVr voltage, equal to:
Δ f osc = K M 2 Δ V osc C 1 Δ Vr R 1 , ( 3 )
will force the feedback loop to react by increasing I FB to compensate for the sudden increase of energy delivery, so V STBY will quickly fall below V th (<V th1 ), thus triggering the same series of events as in the previous case. Note that the change ΔVr does not modify the slope of the ƒ osc (I FB ) relationship.
In this case it is I FB .a=(Vr−V th1 )/R 2 , I FB .b=(Vr−V th )/R 2 .
The circuit in FIG. 10 is a first exemplary circuit that implements the nonlinearity “D” employing a CCO 10 D and a burst mode control circuit 12 D according to an embodiment. The burst mode control circuit 12 D includes a comparator CO 4 having a non-inverting input coupled to the input pin STBY, an inverting input that receives the threshold voltage V th1 , and an output coupled to the base of a transistor Q 21 coupled between the bases of transistors Q 18 , Q 19 and ground. The comparator CO 1 has its inverting and non-inverting inputs respectively coupled to the input pin STBY and the threshold voltage V th and its output coupled to the switch SW and the pulse-train generator 13 . The CCO 10 D has the same structure as that in the circuit in FIG. 8 , with the addition of a transistor Q 20 that mirrors a portion k 1 (k 1 <1) of I R towards a current mirror 36 , including transistors Q 18 , Q 19 , of the burst mode control circuit 12 D. This subtracts the current k 1 I R from the current I R going from Q 13 to the mirror 28 . Thus, this mirror and the subsequent mirrors 14 , 16 , 26 in the chain, mirror (1−k 1 )I R .
As long as I FB <I FB .a (i.e., V STBY >V th1 ), the output of comparator CO 4 is high, Q 21 is on and the mirror 36 is disabled; the current flowing through the chain of mirrors 14 , 16 , 28 is IR and the charge/discharge current for C 1 is KM·IR. As V STBY =V th1 the output of CO 4 goes low, Q 21 is switched off and the mirror 36 is activated; the current flowing through the chain of mirrors 14 , 16 , 28 jumps from IR to (1−k 1 )IR and the charge/discharge current for C 1 to KM·(1−k 1 )IR.
The resulting frequency decrease will force the feedback loop to react by increasing I FB to compensate for the sudden increase of energy delivery, so V STBY will quickly fall below V th (<V th1 ), will assert the output of CO 1 high, thus inhibiting the oscillator through the switch SW and the pulse-train generator 13 .
Also in this circuit it is I FB .a=(Vr−V th1 )/R 2 , I FB .b=(Vr−V th )/R 2 .
The circuit in FIG. 11 is a second exemplary circuit that implements the nonlinearity “D,” and includes a CCO 10 E and a burst mode control circuit 12 E according to another embodiment. The CCO 10 E includes a current mirror 38 ; including transistors Q 2 , Q 3 , Q 4 , Q 22 , Q 23 and inhibit switch SW; transistor Q 24 coupled between Q 22 and ground; transistor Q 25 coupled between Q 23 and ground; a first diode D 1 coupled between the emitters of Q 22 and Q 3 ; and a second diode D 2 coupled between the emitters of Q 23 and Q 4 . In this case the current mirror 38 , which charges and discharges C 1 , is split in two modules: Q 23 +Q 4 (charge), Q 22 +Q 3 (discharge via Q 5 , Q 6 ). Transistors Q 23 and Q 22 mirror a portion k 1 (k1<1) of IR, Q 4 and Q 3 mirror the remaining portion (1−k 1 ) of IR.
As long as V STBY >V th1 , the output of comparator CO 4 is low, Q 24 and Q 25 are off, thus Q 22 and Q 23 deliver their collector current to the mirror Q 5 , Q 6 via diode D 1 and to capacitor C 1 via diode D 2 , respectively. Therefore, the charge/discharge current for C 1 is KM·IR. As V STBY =V th1 the output of CO 4 goes high, Q 24 and Q 25 are turned on, thus the collector current k 1 IR of both Q 22 and Q 23 is diverted to ground. The diodes D 1 and D 2 isolate Q 24 and Q 25 so that the oscillator operation is unaffected except for the charge/discharge current for C 1 that jumps to KM·(1−k 1 )IR.
Also in this case, the resulting frequency decrease forces the feedback loop to react by increasing I FB to compensate for the sudden increase of energy delivery, so V STBY quickly falls below V th (<V th1 ), which asserts the output of comparator CO 1 high, thus inhibiting the oscillator through the switch SW and the pulse-train generator 13 .
I FB .a and I FB .b are the same as in the previous circuit.
The circuit in FIG. 12 is a third exemplary circuit that implements the nonlinearity “D,” and includes a CCO 10 F and a burst mode control circuit 12 F according to a further embodiment.
The burst mode control circuit 12 F is the same as the burst mode control circuit 12 B of FIG. 9 . The CCO 10 F is the same as that shown in FIG. 3 except for the addition of a single-pole double-throw switch SPDT 2 that is configured to switch the reference voltage on the non-inverting input of the comparator CO 2 between a first value V V1 and a second value V V2 <V V1 . Either value is selected by the output of the comparator CO 4 : if the output is high (which occurs when V STBY >V th1 ), the single-pole double-throw switch SPDT 2 connects the non-inverting input to V V1 , otherwise to V V2 . Note that V V1 corresponds to the 0.9 V reference voltage shown in the schematics in FIGS. 7 to 11 .
As long as V STBY >V th1 , the output of CO 4 is high and the oscillator swing is ΔVosc=3.9−V V1 . As V STBY =V th1 and the output of CO 4 goes low, the peak-to-valley swing ΔVosc will increase by the difference V V1 −V V2 , thus originating a step reduction both in ƒ osc (I FB ) and in the slope of ƒ osc (I FB ) (refer to eq. 1), like the first two exemplary circuits. This frequency drop will force the feedback loop to react by increasing I FB to compensate for the sudden increase of energy delivery, so V STBY will quickly fall below V th (<V th1 ), the output of CO 1 will be asserted high, thus inhibiting the oscillator through the switch SW, and the pulse-train generator.
I FB .a and I FB .b are still the same.
Obviously, the very same functionality can be obtained by changing the reference voltage for comparator CO 3 from a first value Vp 1 (=3.9 V) to a second value Vp 2 >Vp 1 .
It is worth noticing that the nonlinearity “E” can be thought as the combination of nonlinearity “D” and nonlinearity “A”. As such, one embodiment of its implementation can be the combination of the circuit in FIG. 7 and the circuit in FIG. 10 . This is shown in the exemplary circuit in FIG. 13 , which includes a CCO 10 G and a burst mode control circuit 12 G.
As long as I FB <I FB .a (i.e., V STBY >V th ), where I FB .a=(Vr−V th1 )/R 2 , it is I R2 =I FB and I S =0. The output of CO 4 is high, Q 21 is on and the mirror 36 is off; the current flowing through the chain of mirrors 16 , 26 , 28 is IR and the charge/discharge current for C 1 is KM·IR. As V STBY =V th1 the output of CO 4 goes low, Q 21 is switched off and the mirror 36 is activated; the current flowing through the chain of mirrors 16 , 26 , 28 jumps from IR to (1−k 1 )IR and the charge/discharge current for C 1 to KM·(1−k 1 )IR.
The resulting frequency decrease will force the feedback loop to react by increasing I FB to compensate for the sudden increase of energy delivery, so V STBY will quickly fall and reach V th (<V th1 ). The precision clamp made up of the op-amp OA 2 and Q 8 is activated and prevents V STBY from further decreasing. Therefore, as the optocoupler sinks a current I FB >(Vr−V th )/R 2 , I R2 is constant, and so is the oscillator frequency. The extra current I S is provided by Q 8 . This current is mirrored by current mirror 22 and compared to the reference current I ref mirrored by mirror 24 . As long as I S <I ref the collector of Q 11 is substantially at Vcesat and the output of the comparator CO 1 is low. When I S becomes larger than I ref , the Vce of Q 11 goes up and as it exceeds Vth 2 the output of CO 1 goes high and inhibits the oscillator through the switch SW and the pulse-train generator 13 .
In this circuit it is: I FB .a=(Vr−V th1 )/R 2 , I FB .b=(Vr−V th )/R 2 +I ref .
According to an alternative embodiment, the implementation of nonlinearity “E” can be the combination of the circuit in FIG. 7 and the circuit in FIG. 11 . This is shown in the circuit in FIG. 14 , which includes a CCO 10 H and a burst mode control circuit 12 H.
As long as I FB <I FB .a (i.e., V STBY >V th ), where I FB .a=(Vr−V th1 )/R 2 , it is I R2 =I FB and I S =0. The output of CO 4 is low, Q 24 and Q 25 are off, thus Q 22 and Q 23 deliver their collector currents to the mirror Q 5 , Q 6 via D 1 and to C 1 via D 2 , respectively. Therefore, the charge/discharge current for C 1 is KM·IR. As V STBY =V th1 the output of CO 4 goes high, Q 24 , Q 25 are turned on, thus the collector current k 1 IR of both Q 22 and Q 23 is diverted to ground. The diodes D 1 and D 2 isolate Q 24 and Q 25 so that the oscillator operation is unaffected except for the charge/discharge current for C 1 that jumps to KM·(1−k 1 )IR.
Again, the resulting frequency decrease will force the feedback loop to react by increasing I FB to compensate for the sudden increase of energy delivery, so V STBY will quickly fall down to V th (<V th1 ). The precision clamp made up of the op-amp OA 2 and Q 8 is activated and prevents V STBY from further decreasing. Therefore, as the optocoupler sinks a current I FB >(Vr−V th )/R 2 , I R2 is constant, and so is the oscillator frequency. The extra current I S is provided by Q 8 . This current is mirrored by Q 13 , Q 14 and compared to the reference current I ref mirrored by Q 9 , Q 10 . As long as I S <I ref the collector of Q 11 is substantially at Vcesat and the output of the comparator CO 1 is low. When I S becomes larger than I ref , the Vce of Q 11 goes up and as it exceeds V th2 the output of CO 1 goes high and inhibits the oscillator through the switch SW and the pulse-train generator 13 .
In this circuit it is: I FB .a=(Vr−V th1 )/R 2 , I FB .b=(Vr−V th )/R 2 +I ref .
Finally, according to an embodiment, the implementation of nonlinearity “E” can be the combination of the circuit in FIG. 7 and the circuit in FIG. 12 . This is shown in the circuit in FIG. 15 , which includes a CCO 10 I and a burst mode control circuit 12 I.
As long as I FB <I FB .a (i.e., V STBY >V th ), where I FB .a=(Vr−V th1 )/R 2 , it is I R2 =I FB and I S =0. The output of CO 4 is high and the single-pole double-throw switch SPDT connects the non-inverting input to V V1 >V V2 , so that the oscillator swing is ΔVosc=3.9−V V1 . As V STBY =V th1 and the output of CO 4 goes low and the swing ΔVosc increases by the difference V V1 −V V2 , thus originating a step reduction in ƒ osc (I FB ).
Once more, the resulting frequency decrease will force the feedback loop to react by increasing I FB to compensate for the sudden increase of energy delivery, so V STBY will quickly fall down to V th (<V th1 ), thus triggering the same series of events as in the previous cases.
Among the five nonlinearities considered so far, the nonlinearity “A” has the advantage of leaving the CCO unchanged but appears to be the least effective since it exercises just a mild clamping action on the oscillator frequency. Additionally, it has the least flexibility: it is just a fixed change of slope to zero. All the others appear to be more effective because they exercise a stronger action on the oscillator frequency (they actually reverse the feedback from negative to positive) and the intensity of their action can be adjusted by changing either the mirroring ratios or the switched reference voltages.
The nonlinearity “C” has also the advantage of keeping the CCO unchanged but introduces a fixed jump in the oscillator frequency proportional to the minimum switching frequency ƒ osc .min=ƒ osc (0) (refer to equations 1 and 3) and not to the switching frequency in the discontinuity point ƒ osc (I FB .a). This means that, depending on the frequency range, this discontinuity could be too large in some cases or too small in others. Programming the amplitude of the discontinuity with an external circuit could be a solution but would employ an additional dedicated pin, which might not be available. The discontinuity “C”, therefore, will not be considered for integration.
The simplest implementation seems to be that of the nonlinearity “D”, in particular the circuit in FIG. 12 , in which are added just a comparator CO 4 and the switch SPDT 2 . The experimental verifications have been therefore focused on nonlinearity “D”, although nonlinearities “B” and “E” look promising in terms of performance too and are definitely worth further investigations.
To evaluate the effectiveness in terms of light load efficiency improvement an experiment has been realized using an external circuit to simulate that kind of nonlinearity. To this purpose, the circuit of FIG. 16 has been built and connected to the resonant controller L 6599 mentioned earlier, and the effectiveness evaluated on a 90 W LLC resonant converter (Vin=400 V, Vout=19 V).
The circuit is composed of a current generator (R 3 , R 4 , D 4 , Q 26 ) that sources about 20 μA when the base of Q 26 is pulled low via R 5 by the output of one of the comparators included in the LM 393 . This comparator receives on its inverting input a reference voltage generated by the shunt regulator TL 431 and the adjustment circuit composed of R 6 , R 9 and the potentiometer R 8 . The non-inverting input is connected to STBY through R 7 that, in combination with R 10 provides the comparator with a small hysteresis. R 8 has been tuned to the values of V th , and the hysteresis V H of CO 1 in the L 6599 , to properly set the position of I FB .a at (Vr−V th −V H )/R 4 .
When transistor Q 26 is turned on, the current IR has a sudden 20 μA negative step change. 20 μA is about 10% of IR when I FB =I FB .a. This causes an equal change in the charge/discharge current of C 1 (in the L 6599 , KM=1) and, therefore, a proportional reduction in the switching frequency, which triggers the above described reversal of the feedback sign and pushes V STBY below V th .
It is worth noticing that this circuit implements the nonlinearity “C” and not the nonlinearity “D”. In fact, the circuit of FIG. 16 , although similar in concept to the circuit in FIG. 10 , subtracts a fixed amount of current, so it creates a discontinuity in ƒ osc (I FB ) but leaves its slope unchanged. However, as previously highlighted, for small discontinuities like in our case they are almost indistinguishable, so their difference in terms of performance is not expected to be significant.
The results of the bench evaluation of the experimental converter are summarized in the graph of FIG. 17 , where the efficiency with and without the external circuit are compared. The load range taken into consideration goes from 0.25 to 7.5 W, i.e., from 0.28% to 8.3% of the nominal load. In this range the external circuit has brought an efficiency rise around 5% on average. As shown in the oscilloscope pictures of FIG. 18 , the increase in the output voltage ripple is moderate and, for most applications, tolerable: from 1% to 1.2% of Vout.
One skilled in the art will recognize that corresponding voltage-controlled oscillators could be used in place of the current-controlled oscillators discussed above.
REFERENCES
[1] B. Wang, X. Xin, S. Wu, H. Wu, J. Ying, “Analysis and Implementation of LLC Burst Mode for Light Load Efficiency Improvement”, Applied Power Electronics Conference and Exposition, 2009. APEC 2009. Twenty-Fourth Annual IEEE, Page(s): 58-64.
[2] J. Qin, Z. Moussaoui, J. Liu, G. Miller, “Light Load Efficiency Enhancement of a LLC Resonant Converter”, Applied Power Electronics Conference and Exposition (APEC), 2011 Twenty-Sixth Annual IEEE, Page(s): 1764-1768
[3] F. Weiyi, F. C. Lee, P. Mattavelli, H. Daocheng, C. Prasantanakorn, “LLC resonant converter burst mode control with constant burst time and optimal switching pattern”, Applied Power Electronics Conference and Exposition (APEC), 2011 Twenty-Sixth Annual IEEE, Page(s): 6-12
[4] Y. Liu, “High Efficiency Optimization of LLC Resonant Converter for Wide Load Range”. Thesis, Virginia Polytechnic Institute and State University, 2007.
The various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.
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An effective method enhances energy saving at low load in a resonant converter with a hysteretic control scheme for implementing burst-mode at light load. The method causes a current controlled oscillator of the converter to stop oscillating when a feedback control current of the output voltage of the converter reaches a first threshold value, and introduces a nonlinearity in the functional relation between the frequency of oscillation and said feedback control current or in a derivative of the functional relation, while the control current is between a lower, second threshold value and the first threshold value, such that the frequency of oscillation remains equal or smaller than the frequency of oscillation when the control current is equal to the second threshold value. Several circuital implementations are illustrated, all of simple realization without requiring any costly microcontroller.
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This is a division, of application Ser. No. 439,732, filed Feb. 5, 1974, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates in general to safety seat belt buckles and, more particularly, to a design which provides an optimum combination of design features and parameters to provide a functional combination of high strength, small size, low weight, ease of use and versatility in use together with a reasonable cost to manufacture.
There are a large number of safety seat belt designs which have been used and are being used as well as a large number of designs that have been proposed and are known in the art. It is simple enough to design a buckle to readily meet any one or two given functional criteria as long as other functional criteria are sacrificed. However, as a practical matter there must be a trade-off between such characteristics as low weight and small size on the one hand and structural strength on the other hand. Ease and cost of manufacture is another feature which must be traded off against both weight and size as well as against strength. Other important functional features are ease of manipulation so that the passenger or driver can readily buckle and unbuckle when required. Furthermore, since the use of a seat belt requires some degree of minimum acceptance by the riding public, aesthetic features and simplicity in use as well as weight and size are factors to take into consideration in any given design in order to enhance the likelihood that as large a number of users as possible will in fact use the seat belt rather than try to defeat any system in which the seat belts are used.
Accordingly, the main purpose of this invention is in a seat belt buckle design that provides an optimum combination of parameters that include weight, strength, size, ease of use, reliability, and ease and cost of manufacture.
It is a further purpose of this invention to provide a basic seat belt buckle design which has versatility in that (a) it can be used for a seat belt buckle which either incorporates or omits an electrical switch for an interlock system and (b) it can be used either for a center seat buckle or an outboard seat buckle wherein these two buckles are designed to prevent improper hookup of an outboard seat buckle with a center seat clip and prevent improper hookup of a center seat buckle with an end seat clip. In effect, versatility is another parameter which is part of the optimum combination of parameters to which this invention is addressed.
BRIEF DESCRIPTION OF THE INVENTION
In brief, this invention employs a metal housing within which there is mounted a pushbutton lever, a V-shaped leaf type spring to bias said lever into an upward position, and a single plastic insert for holding an electrical switching arrangement and to provide a crush resistent wall between a plastic cover and the housing. Primarily because of the crush resistent wall on the plastic insert, the cover is designed so that it does not bear or have to resist any significant loading forces. The cover can thus be varied for aesthetic purposes or for the purpose of making sure that the center seat buckle and clip are noncompatible with the outboard seat buckle and clip. The pushbutton lever has sufficient mechanical advantage so that the wearer can readily release the clip and buckle even when there is considerable tension in the webbing to which the clip and buckle are connected. A coil spring loaded rotatable shaft having a radially extending finger serve to make or break the electrical switch connection. The finger is engaged by the leading edge of the clip during buckling and causes the shaft to which it is connected to rotate so that one of the coil spring ends is brought into contact with the electrical circuit to complete the circuit indicating that the buckling has occurred.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing an assembled buckle and an associated clip of a first embodiment of this invention.
FIG. 2 is a perspective view showing an assembled buckle and associated clip of a second embodiment of this invention; the difference between the embodiments shown in FIGS. 1 and 2 being in the buckle cover and in the clip configuration.
FIG. 3 is a perspective view of the buckle of this invention with the cover removed.
FIG. 4 is a plan view of the FIG. 3 buckle in partial cross section with the cover removed and without the push button release lever thereby showing the spring underlying the lever and the electrical connections used to indicate that buckling has been completed.
FIG. 5 is a perspective partial blow-up showing three portions of the buckle in blow-up fashion; the three portions being (a) the cover which is shown in partial cross section, (b) the crush bar member together with the electrical connections carried thereon, and (c) the housing with the release lever assembled thereon and the spring, in invisible lines, beneath the lever.
FIG. 5A is a partial view illustrating the relationship of a housing wall opening and lever tabs.
FIG. 6 is a perspective blow-up, excluding the cover, of the five remaining major elements of the buckle; namely from top to bottom, the electrical connection arrangement, the crush bar member, the lever, the spring and finally the housing.
FIG. 7 is a perspective blow-up view of the rotatable shaft and biasing spring mounted thereon which spring also operates to provide an electrical contact.
FIG. 8 is a longitudinal cross-section through the buckle in the unbuckled state.
FIG. 9 is a longitudinal cross-section through the buckle showing the condition where the clip has been inserted and thus is the buckled state.
FIG. 10 is a longitudinal cross-section similar to that of FIGS. 8 and 9 showing the release lever depressed and the clip being ejected from the buckle.
FIGS. 11 and 12 represent a first embodiment of the electrical contact arrangement in which the contact is normally open during the unbuckled state; FIG. 11 showing a perspective view of the contact and FIG. 12 showing a cross-sectional view through the rotatable shaft and operative finger attached thereto.
FIGS. 13 and 14 are similar to that of FIGS. 11 and 12 except that they represent a second embodiment of the contact arrangement wherein the electrical contact is normally closed during the unbuckled state.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 2 illustrate one of the advantages of the basic buckle design of this invention. FIG. 1 shows a buckle 20 and associated clip 21 for an outboard seat while FIG. 2 represents a buckle 22 and associated clip 23 for a center seat. The arrangement shown prevents incorrect buckling of a clip with a buckle for which it is not associated. Yet both buckles use the same basic structure, the most significant difference between the buckle 20 and the buckle 22 being in the covers 24 and 25 respectively. One of the advantages of this invention is that the buckle cover design can be substantially ornamental because it is not load bearing nor does it provide support or positioning for the components of the buckle. Thus, the cover 24, 25 can be designed to provide a new functional feature which is to avoid the improper buckling of dissociated clip and buckle.
Comparing the FIG. 2 arrangement to the FIG. 1 arrangement, the housing 27 of the FIG. 2 buckle is slightly longer than the housing 26 of the FIG. 1 buckle so that the shoulder 28 of the clip 21 will abut against the forward end of the housing 27 and thus prevent latching of the clip 21 in the buckle 22. The FIG. 2 cover 25 has a recessed forward end 29 which mates with a forward projection 30 of a housing 31 on the clip 23. This housing 31 covers the usual friction holding roll (not shown) that is required to permit adjusting the length of the belt strap 32 on the center seat. Since the center seat is not designed with a retractor this older method of adjusting belt 32 length has to be employed and thus the housing 31 exists as a base for providing the additional mating projection 30. Because the shoulder 33 of the clip 23 is further back from the latching opening 34 of the clip 23 than is the case of the FIG. 1 clip, the FIG. 2 clip 23 can proceed further into the buckle housing 27 than can the FIG. 1 clip 21. But because of the projection 30 on the FIG. 2 clip 23, the FIG. 1 buckle cover 24 will prevent the FIG. 2 clip 23 from extending sufficiently far into the FIG. 1 buckle 20 to latch.
The rest of the figures all relate to the same embodiment with a minor exception as to an electrical contact mechanism as shown in FIGS. 13 and 14. A basic terminology usage herein should be defined. As used herein, the forward end of the buckle is considered to be the end having the opening that admits the clip. Thus, the back end of the buckle 20 is the end which is attached to the buckle strap 38. Similarly, the front end of the clip 21 is considered herein to be the end that enters the front end of the buckle 20 while the back portion of the clip 21 is the portion to which the clip strap 39 is connected. The top of the buckle 20 is considered to be the cover 24 while the base or bottom is the opposite surface, which is the main surface 41 of the housing 42. Thus when a first element is described as being above a second element, that means the first element is close to the cover 24 than is the second element.
The buckle 20 is composed of a housing 42 within which there is mounted a manually operated lever 43 and a generally V-shaped leaf spring 44 (best seen in FIG. 6). The leaf spring 44 is positioned between the housing base 41 and the forward portion of the lever 43. The spring 44 biases the lever 43 into its normally up position. The lever 43 can be depressed toward the housing base 41 only so long as user digital pressure is maintained on the pushbutton 45 portion of the lever 43.
The lever 43 has a forward edge 43a, two sidewardly extending ears 43e, a clip engaging latch portion 43c, an opening 43d rearward of the latch portion 43c and the substantially horizontal pushbutton portion 45. The lever ears extend into pie-shaped openings 62a in the side wall 62 of the housing 42.
As a further matter of terminology, the term horizontal is used herein to denote substantial parallelism to the base 41 and the term vertical denotes substantial perpendicularity to the base 41.
In addition, a plastic crush bar unit 48 is mounted in the housing 42 rearward of the leaf spring 44. This unit 48 includes a three-sided U-shaped wall 50 positioned around the pushbutton 45 and extending from the housing base 41 to slightly above the plane of the pushbutton 45. This wall 50 will take any loading that may be applied between the cover 24 and the housing 42 thereby providing a crush resistent buckle design. By employing this wall 50 to give the crush resistent parameter, the cover 24 can be designed and is designed without requiring the structural strength that would otherwise be required if the cover 24 had to be relied on to provide the crush resistent parameter. Thus, the alternate cover design shown in FIG. 2 is facilitated.
The unit 48 has three forwardly projecting legs 51, 52 and 53. A small rotatable shaft 54 is mounted on the center leg 52. A finger 55 extends out from this shaft 52. A coil spring 56 is mounted on the shaft 54 and engages the shaft 54 (as shown in FIG. 6) so as to bias the shaft to a rotational position where the finger 55 extends upward (see FIGS. 3 and 8). When so biased, the finger 55 is rotated against an end wall 52a of the center leg 52 thereby preventing further rotation of the shaft 54 and causing the finger 55 to normally project above the wall 52a. When the clip 21 is inserted into the buckle 20, the leading edge of the clip will abut against the forwardly facing side of the finger 55 forcing the finger 55 back thereby rotating the shaft 54 and the coil spring 56 mounted thereon. The two U-shaped electrical connections 57, 58 are positioned so that the connection 57 is in continuous contact with one end 56a of the coil spring 56 (see FIG. 6). The other end 56b of the coil spring 56 is normally in the open position shown in FIG. 12. But, when the finger 55 is moved back causing the shaft 54 and coil 56 to rotate (counterclockwise as seen in FIG. 12), the end 56b rotates down into contact with the second connection element 58 thereby completing an electrical circuit through the buckle 20 from the wire 59 to the wire 60.
As shown in FIGS. 6, 8 and 9, the leaf spring 44 has a base porton 44b which rests against the housing base 41 and two upward and rearward extending arms 44a which bear against the under surface of the lever 43 thereby biasing the lever 43 into its normal upward position. The leaf spring 44 has two upwardly bent side walls 44s which bear against the inner surface of the housing side walls 62 of the housing 42 to position the spring 44 laterally and hold the spring 44 from rattling. Two resilient vertical walls 44c at the back of the leaf spring 44 abut against the crush bar unit 48 and aid in holding snug the parts within the buckle. A tab 44t is bent out from one of the leaf spring side walls 44s to catch into an opening 62b (see FIG. 5A) in the housing 42 side walls 62 and thereby retain the leaf spring 44 against longitudinal movement backward within the housing 42. The opening 62b is an extension of one of the two pie-shaped openings 62a to provide a total opening on one side wall 62 great enough to permit assembling the lever 43 into the housing 42. As shown in FIG. 5A, the spring side walls 44s are stepped to provide a vertical edge 44e. This edge 44e, at least at the opening 62b, holds the lever ear 43e against longitudinal movement back within the opening 62b.
The steel lever 43 includes two sidewardly projecting ears 43e at the front end thereof. These ears fit within the pie-shaped openings 62a of the steel housing side wall 62. The upward limit of rotation of the lever 43 is determined by contact between the ears 43e and the upper edges of the openings 62a. At least nominally, forward movement of the ears 62a is determined by the forward edges of the openings 62a. However, the rearward edge 42a of the J-shaped front section of the housing 42 is positioned sufficiently close (10 to 30 mils in one embodiment) to the forward edge 43a of the lever so as to carry a part of the load on the lever 43 when a clip is locked in and exerts a large forward force on the lever 43. This relationship of housing edge 42b to lever edge 43a tends to minimize bowing of the lever 43 under high loads because as the lever 43 deflects under high loads, the J section 42b takes up the load and distributes the load over the entire front edge 43a of the lever.
The crush bar unit 48 in addition to the three wall crush bar 50 and the three forwardly projecting legs 51, 52, 53, also includes two resilient side walls 64. These side walls 64 are integral with the plastic unit 48 but these side walls 64 have a thickness such that they will flex laterally sufficient to permit snapping of the plastic unit 48 into the metal housing 42 by virtue of engagement between side projection 64a on each side wall 64 and openings 62d on each housing side wall 62. The projection 64a are bevelled on the underside so as to facilitate pushing the unit 48 into the housing 42 and so that the projections 64a can ride down the inner surface of the side walls 62 until they snap into the opening 62b.
This crush bar unit 48 also contains a back member 66 which member 66 includes sections 66a that are somewhat U-shaped in cross section so that the sections 66a engage the rear wall of the opening 41a in the base of the housing 42, through which opening 41a the buckle strap 38 is looped for attachment to the buckle 20. Thus, the buckle strap 38 (see FIG. 8) loops around the plastic section 66a and does not directly impinge on the metal wall for the opening 41a. This provides a degree of protection from abraiding and excess local tension on the strap 38.
An acetyl copolymer resin is used for the plastic crush bar unit 48.
In operation, and with particular reference to FIGS. 8, 9 and 10, the buckle 20 in normal unbuckled state is shown in FIG. 8, the buckle 20 in normal buckled state is shown in FIG. 9 and the buckle while the clip is being unbuckled or unlatched is shown in FIG. 10. When the clip 21 is inserted into the front opening 20a of the buckle 20, it is guided by the J-shaped front end 42b of the housing and is held down by inwardly extending flanges 62c of the front part of the housing side wall 62. Thus, the clip 21 is constrained to contact the rearwardly and slightly upwardly sloping latch portion 43c of the lever 43. The inward progression of the clip 21 forces the lever 43 to pivot down around a line that is approximately at the contact between the ears 43e and the forward edge of the openings 62a in the side wall 62. When the clip 21 has ridden in far enough, the clip opening 68 will be engaged by the rearwardly facing shoulder of the latch portion 43c permitting the lever 43 to snap back up to the position shown in FIG. 9 and thereby positively hold in the clip 21. At the same time, as disclosed above, the forward end of the clip 21 contacts the upwardly extending finger 55 causing it to rotate counterclockwise as seen in the drawings and causing the terminals 58 and 56b to contact thereby completing an electric circuit and providing an indication that the clip 21 is indeed latched into the buckle 20 and thus that the occupant is buckled up. It will be noted that the finger 55 projects up through the opening 43d immediately rearward of the latch portion 43c so that the clip 21 will contact the finger 55 during insertion.
One advantageous feature of the finger 55 design and arrangement shown can best be understood with reference to FIG. 10. On release of the clip 21, the passenger depresses the push button 45 portion of the lever 43 thereby bringing the latch portion 43c below the lever of the clip 21 so that the clip 21 can be pulled out. However, in addition, the finger 55 is biased by the spring 56 to move in a clockwise direction. Thus, as may be seen in FIG. 9, the finger 55 exerts a small upward and backward pressure on the clip 21. This pressure has no effect during the buckled state except perhaps to better seat the clip 21 against the rearwardly facing edge of the latch 43c. However, once the lever 43 and its latch 43c has been moved out of the way, the relatively small pressure exerted by the finger 55 meets no resistance and thus tends to move the clip 21 out of the buckle 20. This not only provides an improved passenger feel for the releasing mechanism, but also aids to assure that the clip 21 does not sit in place and thus is not relatched upon release of the disengaging pressure on the push button 45.
FIGS. 13 and 14 illustrate an embodiment in which the normally open terminals 58 and 56b (as shown in FIGS. 11 and 12) are normally closed terminals 58' and 58b. The buckled-up state is thus indicated by the opening of an electric circuit rather than the closing of a circuit. Otherwise, this FIGS. 13 and 14 arrangement is the same as shown in the other FIGS. and the same reference numerals are therefore used.
An advantageous feature of the way in which the lever 43 and spring 44 are mounted in the housing 42 and in which they bear against one another is that these three units 42, 43 and 44 operate as a functional buckle regardless of the condition or even presence of the plastic unit 48 or plastic cover 24. Thus this design enhances safety on collision and extends effective life of the buckle.
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A self-sufficient three-piece structure constituting an open top metal housing within which there is mounted a pushbutton lever and a V-shaped leaf-type spring between lever and base of housing. A single plastic insert providing a crush resistent wall between base of housing and plastic cover also holds an electrical switching arrangement. The electrical switching arrangement includes a rotatable shaft and a radially outward extending finger which is actuated by insertion of the mating clip.
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BACKGROUND OF THE INVENTION
The present invention generally relates to electric heating apparatus and, in a preferred embodiment thereof, more particularly relates to a specially designed dual element electric water heater which is easily field convertible among various heating element control modes without the previous necessity of changing either of the heating element control thermostats or altering the wiring interconnections therebetween.
In a common construction thereof a vertically oriented dual element electric water heater has spaced apart upper and lower resistance type electric heating elements which horizontally extend into the interior of the water storage tank portion of the heater. The operation of these upper and lower heating elements is controlled by upper and lower electric thermostats which are respectively associated with the upper and lower heating elements.
Various modes of operating the upper and lower heating elements, with either single or three phase electric power supply to the water heater, are typically available. Representatively, these heating element operational modes include (1) single phase simultaneous element operation, in which the two heating elements are simultaneously cycled by their associated thermostats; (2) single phase simultaneous element operation with 4 wire outlet operation, (3) single phase non-simultaneous element operation, in which the two heating elements are independently cycled by their associated thermostats, (4) single phase non-simultaneous element operation with 4 wire outlet operation; (5) single phase non-simultaneous element operation with 3 wire outlet operation; (6) three phase simultaneous element operation; and (7) three phase non-simultaneous element operation. The two heating element-controlling thermostats are typically disposed in openings formed in the jacket insulation structure of the water heater that surrounds its storage tank portion. The electrical wiring that operatively interconnects the thermostats is, for the most part, disposed between the tank and the insulation structure.
In the past, in order to provide these seven representative element control modes seven separate embodiments or “variants” of the water heater needed to be built, with each water heater variant having different thermostat wiring configurations and/or combinations of thermostat types. The need to build separate variants to provide all of the representative types of heating element control listed above carries with it several problems, limitations and disadvantages.
For example, the construction of the water heater is made more complex since, in essence, it needs to be constructed in seven different ways—each having a different thermostat type combination and/or thermostat wiring interconnection configuration. Additionally, and quite importantly, once the water heater is constructed to provide a predetermined element: control mode, it is not practical or economical to alter this selected control mode. This is due to the fact that to alter the originally built-in element control mode, changes must be made to the thermostat wiring and/or the types of thermostats used must be altered. Because the thermostat interconnection wiring is disposed between the jacket insulation structure and the water heater storage tank portion such wiring is, as a practical matter, inaccessible for such conversion.
Accordingly, if a dual element water heater constructed in this conventional manner does not provide the desired heating element control mode, it has to be replaced with another manufactured variant of the water heater that has the desired heating element control mode incorporated therein during its original manufacture. In view of this it can be readily seen that a need exists for a dual element electric water heater which eliminates or at least substantially reduces the above-mentioned problems, limitations and disadvantages typically associated with conventionally constructed dual element electric water heaters. It is to this need that the present invention is directed.
SUMMARY OF THE INVENTION
In carrying out principles of the present invention, in accordance with a preferred embodiment thereof, a liquid heating apparatus having first and second spaced apart liquid heating elements is provided. The apparatus is representatively in the form of an electric water heater having vertically spaced apart upper and lower electric resistance type heating elements that horizontally extend into the interior of a water storage tank portion of the water heater. First and second electric thermostats are respectively and controllingly associated with the upper and lower heating elements, and wiring, representatively in the form of a wiring harness, is operatively connected to the first and second thermostats and has lead end portions variably connectable to a source of electrical power. The water heater also preferably includes a junction box having a terminal block portion with line side terminals to which electrical power supply leads may be variably connected, and water heater side terminals to which the aforementioned wiring harness lead end portions may be variably connected.
Preferably, the first electric thermostat, which controls the upper heating element, is of a single pole double throw configuration, and the second electric thermostat, which controls the lower heating element, is of a single pole single throw configuration. The wiring harness is connected to the first and second thermostats in a manner such that, without replacing either of the first and second thermostats and/or altering the wiring connections to either thermostat, a plurality of heating element control modes may be provided simply by changing the wiring connections to the terminal block.
Representatively, these element control modes include (1) a single phase simultaneous dual element control mode, (2) a single phase simultaneous dual element control mode with four wire outlet operation, (3) a single phase non-simultaneous dual element control mode, (4) a single phase non-simultaneous dual element control mode with four wire outlet operation, (5) a single phase non-simultaneous dual element control mode with three wire outlet operation, (6) a three phase simultaneous dual element control mode, and (7) a three phase non-simultaneous dual element control mode.
In an illustrated preferred embodiment of the electric water heater, the first electric thermostat has an ECO portion with first, second, third and fourth power supply terminals, and a switch portion with a switch power terminal and first and second switch contacts. The second electric thermostat has an ECO portion with first, second, third and fourth power supply terminals, a switch power terminal and a switch contact.
Additionally, the wiring harness includes (1) a first wire interconnected between the first power supply terminal of said first thermostat ECO portion and the switch power terminal of the first thermostat switch portion, (2) a second wire interconnected between the first switch contact of the first thermostat switch portion and the upper heating element, (3) a third wire interconnected between the fourth power supply terminal of the first thermostat ECO portion and the upper heating element, (4) a fourth wire interconnected between the first power supply terminal of the second thermostat ECO portion and the switch power terminal of the second thermostat, (5) a fifth wire interconnected between the switch contact of the second thermostat switch portion and the lower heating element, (6) a sixth wire interconnected between the fourth power supply terminal of the second thermostat ECO portion and said lower heating element, and (7) a series Of electrical leads each having a first end portion operatively connected to one of the first and second thermostats, and a second end variably connectable to the water heater side of the terminal block.
The series of wiring harness leads variably connectable to the water heater side of the terminal block preferably include (1) a first lead connected at one end to the first power supply terminal of the second thermostat ECO portion and variably connectable at the other end to the water heater side of the terminal block, (2) a second lead connected at one end to the first power supply terminal of the first thermostat ECO portion and variably connectable at the other end to the water heater side of the terminal block, (3) a third lead connected at one end to the second power supply terminal of the first thermostat ECO portion and variably connectable at the other end to the water heater side of the terminal block, (4) a fourth lead connected at one end to the second switch contact of the first thermostat switch portion and variably connectable at the other end to the water heater side of the terminal block, and (5) a fifth lead connected at one end to the second power supply terminal of the second thermostat ECO portion and variably connectable at the other end to the water heater side of the terminal block.
In a preferred embodiment of the dual element electric water heater the water heater has an external well area in which the terminal block ends of the wiring harness leads may be disposed prior to their operative connection to the terminal block, and the junction box is removably connectable to the water heater and may be shipped loose therewith for subsequent mounting thereon and operative connection to external power supply leads and the terminal block ends of the wiring harness leads.
While the liquid heating apparatus of the present invention is representatively an electric water heater, it could alternatively be a variety of other types of liquid heating apparatus. Additionally, while the outer ends of the aforementioned wiring harness leads are representatively connectable in selectively variable manners to a terminal block portion of a junction box, it will be readily appreciated by those of skill in this particular art that they could alternatively be variably connected to an electrical power source in a variety of other manners if desired.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a highly schematic cross-sectional view through a field conversion dual element electric water heater embodying principles of the present invention;
FIG. 2 is a schematic wiring diagram of a thermostat/heating element portion of the water heater; and
FIG. 3 is a schematic diagram of a junction box/terminal block structure operatively associated with the heating element control thermostats of the water heater.
DETAILED DESCRIPTION
Schematically illustrated in FIG. 1 is a dual element electric water heater 10 embodying principles of the present invention. Water heater 10 includes a vertically oriented cylindrical metal water storage tank 12 which has, at its top end, suitable water inlet and outlet piping connections 14 and 16 . Vertically spaced apart elongated upper and lower electric resistance type water heating elements 18 and 20 longitudinally extend horizontally into the interior of the tank 12 from a vertical sidewall portion thereof. The tank 12 is surrounded by an insulation jacket structure 22 including an outer metal skin portion 24 and a foamed-in insulation material 26 interposed between the metal skin portion 24 and the tank 12 .
Extending along a vertical side portion 12 a of the tank through which the upper and lower heating elements 18 , 20 inwardly extend is an insulating bag structure 28 which is filled with the insulating material 26 and has a vertically spaced pair of peripherally sealed access openings 30 , 32 extending therethrough and respectively positioned somewhat above the outer ends of the upper and lower heating elements 18 , 20 . Bag openings 30 , 32 are respectively aligned with sidewall access openings formed in the jacket metal skin portion 24 and covered by removable access plates 34 and 36 . Upper and lower electric thermostats 38 , 40 are respectively received in the bag access openings 30 , 32 and may be accessed by removing the plates 34 and 36 .
The upper and lower thermostats 38 and 40 are respectively and controllingly coupled to the upper and lower heating elements 18 , 20 and are electrically interconnected to one another by a subsequently described wiring harness 42 which is disposed between the insulation bag 28 and a vertical sidewall portion of the tank 12 . During shipment of the water heater 10 , upper end portions of various individual wires which make up the harness 42 are placed in a top end well area 44 in the water heater 10 for subsequent operative connection to a terminal block portion 46 of a junction box 48 . Representatively, the junction box 48 is shipped loose with the water heater and is subsequently attached to a top end portion thereof as schematically depicted in FIG. 1 .
Turning now to FIG. 2, in the illustrated preferred embodiment of the dual element electric water heater 10 , the upper thermostat 38 is of a single pole double throw configuration and has an ECO (energy cut-off) high limit control portion 38 a operatively associated with a switch portion 38 b , and the lower thermostat 40 is of a single pole single throw configuration and has an ECO high limit control portion 40 a operatively associated with a switch portion 40 b.
The upper thermostat ECO portion 38 a has power supply terminals 50 , 52 , 54 , 56 , and the upper thermostat switch portion 38 b has a switch power terminal 58 and switch contacts 60 and 62 . The lower thermostat ECO portion 40 a has power supply terminals 64 , 66 , 68 , 70 , and the lower thermostat switch portion 40 b has a switch power terminal 72 and a switch contact 74 .
Wiring harness 42 includes a wire 76 interconnected between the power supply terminal 54 and the switch power terminal 58 ; a wire 78 interconnected between the switch contact 60 and the upper heating element 18 ; a wire 80 interconnected between the power supply terminal 56 and the upper heating element 18 ; a wire 82 interconnected between the power supply terminal 68 and the switch power terminal 72 ; a wire 84 interconnected between the switch contact 74 and the lower heating element 20 ; and a wire 86 interconnected between the power supply terminal 70 and the lower heating element 20 .
The wiring harness 42 also includes five water heater power connection leads WH 1 ,-WH 5 which are connectable in various subsequently described, selectively variable manners to the terminal block portion 46 of the junction box 48 to provide the upper and lower heating elements with a variety of control modes without the necessity of removing and replacing either of the thermostats 38 , 40 and/or altering any of the wiring that interconnects the thermostats 38 , 40 . The power connection leads WH 1 -WH 5 extend upwardly from the thermostats 38 , 40 behind the insulation bag 28 (see FIG. 1 ), with upper end portions of the leads WH 1 -WH 5 being received in the well area 44 prior to connection of such upper lead end portions to the terminal block 46 as subsequently described herein.
As schematically depicted in FIG. 2, the lower end of lead WH 1 is connected to the lower thermostat power supply terminal 64 ; the lower end of lead WH 2 is connected to the upper thermostat power supply terminal 50 ; the lower end of lead WH 3 is connected to the upper thermostat power supply terminal 52 ; the lower end of lead WH 4 is connected to the upper thermostat switch contact 62 ; and the lower end of lead WH 2 is connected to the lower thermostat power supply terminal 66 .
Turning now to FIG. 3, the terminal block portion 46 of the junction box 48 has a line side 46 a with terminals L A -L D , and a water heater side 46 b with terminals H A -H D electrically coupled to the line side terminals L A -L D as indicated by the dashed lines. With the junction box 48 operatively mounted on the top end of the water heater 10 as schematically shown in FIG. 1, the control mode of the water heater's upper and lower heating elements 18 , 20 may be selectively varied simply by reconfiguring various wiring connections to the terminal block 46 as will now be described.
Representatively, there are seven different dual heating element operational control modes available for the water heater 10 simply by altering the wiring connections to the terminal block 46 , and without changing the wiring interconnection between the thermostats 38 , 40 and/or replacing either thermostat with another type of thermostat. These seven heating element operational control modes, and the terminal block wiring configurations that yield them, are as follows:
Single Phase Simultaneous Dual Element Control Mode
As schematically depicted in FIG. 3, to provide the water heater 10 with a single phase, simultaneous control of its upper and lower electric resistance type upper and lower heating elements 18 and 20 , single phase power supply lines 88 , 90 are respectively connected to the terminal block line side terminals L A and L B . On the water heater side 46 b of the terminal block 46 wiring harness leads WH 1 and WH 2 are connected to the terminal H A , wiring harness leads WH 3 and WH 5 are connected to the terminal H B , and the wiring harness lead WH 4 is connected to the terminal H C .
Single Phase Simultaneous Dual Element Control Mode With 4 Wire Outlet Operation
To provide this dual element operational control mode, the two single phase power supply leads are connected to terminals L A and L B on the line side 46 a of the terminal block 46 . On the water heater side 46 b of the terminal block 46 , wiring harness lead WH 2 is connected to terminal H A , wiring harness lead WH 3 is connected to terminal H B , and wiring harness lead WH 4 is connected to terminal H C . Wiring harness leads WH 1 and WH 5 are connected to an off peak meter or timer.
Single Phase Non-Simultaneous Dual Element Control Mode
To provide this dual element operational control mode, the two single phase power supply leads are connected to terminals L A and L B on the line side 46 a of the terminal block. On the water heater side 46 b of the terminal block 46 wiring harness leads WH 1 and WH 3 are connected to terminal H B , wiring harness lead WH 2 is connected to terminal H A , and wiring harness leads WH 4 and WH 5 are connected to terminal H C .
Single Phase Non-Simultaneous Dual Element Control Mode With 4 Wire Outlet operation
To provide this dual element operational control mode, the two single phase power supply leads are connected to terminals L A and L B on the line side 46 a of the terminal block. On the water heater side 46 b of the terminal block 46 wiring harness leads WH 1 and WH 3 are connected to terminal H B , wiring harness lead WH 2 is connected to terminal H A , and wiring harness leads WH 4 and WH 5 are connected to terminal H C . Additionally, if off peak metering is desired, an off peak meter or timer is connected to terminals L C and L D on the line side 46 a of the terminal block, wiring harness lead WH 4 is connected to terminal H C , and wiring harness lead WH 5 is connected to terminal H D .
Single Phase Non-Simultaneous Dual Element Control Mode With 3 Wire Outlet Operation
To provide this dual element operational control mode, the two single phase power supply leads are connected to terminals L A and L B on the line side 46 a of the terminal block. On the water heater side 46 b of the terminal block 46 wiring harness lead WH 2 is connected to terminal H A , wiring harness lead WH 3 is connected to terminal H B , and wiring harness leads WH 4 and WH 5 are connected to terminal H C . If off peak metering is desired, wiring harness lead WH 1 is connected to terminal H D and an off peak meter is connected to terminal L D .
Three Phase Simultaneous Dual Element Control Mode
To provide this dual element operational control mode, three phase power supply leads are connected to the terminal block line side terminals L A , L B and L D . On the water heater side 46 b of the terminal block 46 wiring harness leads WH 1 and WH 2 are connected to terminal H A , wiring harness lead WH 3 is connected to terminal H B , wiring harness lead WH 4 is connected to terminal H C , and wiring harness lead WH 5 is connected to terminal H D .
Three Phase Non-Simultaneous Dual Element Control Mode
To provide this dual element operational control mode, three phase power supply leads are connected to the terminal block line side terminals L A , L B and L C . On the water heater side 46 b of the terminal block 46 wiring harness lead WH 1 is connected to terminal H A , wiring harness lead WH 2 is connected to terminal H B , wiring harness lead WH 3 is connected to terminal H C , and wiring harness leads WH 4 and WH 5 are connected to terminal H D .
As can readily be seen from the foregoing, the water heater 10 may uniquely be field-converted selectively among its seven representative dual heating element operational control modes simply by appropriately altering the electrical connections to the terminal block 46 . In contrast to conventionally constructed dual element electric water heaters, there is simply no need to either (1) replace either of the upper and lower thermostats 38 , 40 with another type of thermostat, and/or (2) change the wiring connections to the two thermostats. This advantageously makes the representatively listed seven dual heating element operational control modes available with the single illustrated variant of the dual element electric water heater 10 . While the present invention has been illustratively incorporated in an electric water heater it will be readily appreciated that principles of the invention could also be incorporated in dual element liquid heating devices of other types if desired. It will additionally be appreciated that while the outer ends of the wiring harness leads WH 1 -WH 5 are representatively connectable in selectively variable manners to a terminal block portion of a junction box, they could alternatively be variably connected to an external electrical power source in a variety of other manners if desired.
The foregoing detailed description is to be clearly understood as being given by way of illustration and example, the spirit and scope of the present invention being limited solely by the appended claims.
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An electric water heater has upper and lower electric resistance type heating elements respectively controlled by a single pole, double throw upper thermostat and a single pole, single throw lower thermostat. The upper and lower thermostats are operatively interconnected by a wiring harness having outer wire end portions that may be connected in various orientations to the terminal block portion of an external junction box to provide the water heater with a variety of heating element operating modes without having to replace either of the thermostats or vary the wiring harness interconnections therebetween. The water heater may thus be advantageously manufactured in a single variant that may be easily and quickly modified in the field to selectively alter the heating element control mode of the water heater.
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BACKGROUND
1. Field
The present invention relates to a method for adjusting the resonant frequencies of a vibrating microelectromechanical device.
2. Related Art
Vibrating masses are commonly used elements in microelectromechanical (MEMS) devices such as MEMS resonators and resonant inertial sensors. These microfabricated resonators can be used in MEMS gyroscopes to sense the rotation of the device by measuring changes in vibrational amplitudes upon rotation. In typical vibrating mass gyroscopes, the device may be driven in one axis and the vibrational amplitude sensed in another axis. An example of a resonator structure used in a MEMS gyroscope is the Disc Resonator Gyroscope (DRG) described in U.S. Pat. No. 7,347,095, entitled “Integral Resonator Gyroscope” and U.S. Patent Application Pub. No. 2007/10017287. The resonant frequencies of the device in these two axes are typically required to be identical for operation, and are designed to have common frequencies. However, the process for manufacturing MEMS resonators typically produces devices with resonant frequencies which are not precisely at the desired resonant frequency value for each vibratory axis due to production tolerances. These differences between the resonant frequencies of the MEMS resonator in the drive and sense axes are commonly called frequency splits. These splits are typically tuned into coincidence by an electronic or electromechanical means to enable device operation. Correction methods can be performed to adjust the resonant frequencies of a MEMS resonator in order to correct for frequency splits. However, such correction methods may over or under correct the resonant frequencies and thus do not produce the level of precision necessary to adequately adjust the resonant frequencies of the MEMS resonator. If the frequency split of the MEMS resonator is too large, that is, the resonant frequencies of the MEMS resonator in its operational axes deviate too much from the desired resonant frequencies coincident value, then the MEMS resonator may be inaccurate or be unsuitable for its purpose. Further, the method for implementing these corrections may be incompatible with repeatable volume manufacturing processes.
Thus, there is a need for a method to more efficiently and accurately adjust the resonant frequencies of a vibrating microelectromechanical device to reduce the frequency split of the resonator device.
SUMMARY
In one embodiment, the present invention is a method for adjusting the resonant frequencies of a vibrating mass including the steps of patterning a surface of a device layer of the vibrating mass with a mask, etching the vibrating mass to define a structure of the vibrating mass, determining a first set of resonant frequencies of the vibrating mass, determining a mass removal amount of the vibrating mass and a mass removal location of the vibrating mass to obtain a second set of resonant frequencies of the vibrating mass, removing the mask at the mass removal location, and etching the vibrating mass to remove the mass removal amount of the vibrating mass at the mass removal location of the vibrating mass.
In another embodiment, the present invention is a method for adjusting the resonant frequencies of a vibrating MEMS device including the steps of patterning a surface of the vibrating MEMS device with photoresist, the photoresist having open areas located where the MEMS device should be etched, etching the vibrating MEMS device at locations corresponding to the open areas, determining a first resonant frequency of the vibrating MEMS device along a first axis and a second resonant frequency of the vibrating MEMS device along a second axis, determining a first mass removal amount of the vibrating MEMS device and a first mass removal location of the vibrating MEMS device to alter the first resonant frequency and reduce a resonant frequency difference between the first resonant frequency and the second resonant frequency, removing the photoresist at the first mass removal locations using laser ablation, and etching the vibrating MEMS device to remove the first mass removal amount of the vibrating mass at the first mass removal location of the vibrating MEMS device.
In yet another embodiment, the present invention is a method for adjusting resonant frequencies of a vibrating MEMS device including the steps of determining a first resonant frequency of the vibrating MEMS device along the first axis and a second resonant frequency of the vibrating MEMS device along the second axis, determining a mass removal amount of the vibrating MEMS device and a mass removal location of the vibrating MEMS device to alter the first resonant frequency and reduce a resonant frequency difference between the first resonant frequency and the second resonant frequency, coating a surface of the vibrating MEMS device with a conformal masking material, removing the masking material at the mass removal location using laser ablation, and etching the vibrating MEMS device using deep reactive ion etching to remove the mass removal amount of the vibrating MEMS device at the mass removal location of the vibrating MEMS device.
BRIEF DESCRIPTION OF THE DRAWINGS
The features, objects, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, wherein:
FIG. 1 is a flow chart of an embodiment of the present invention;
FIG. 2 is a side view of a vibrating mass;
FIG. 3 is a side view of a vibrating mass;
FIG. 4 is a side view of a vibrating mass;
FIG. 5 is a side view of a vibrating mass;
FIG. 6 is a top view of a vibrating mass;
FIG. 7 is a flow chart of an alternate embodiment of the present invention;
FIG. 8 is a side view of a vibrating mass;
FIG. 9 is a side view of a vibrating mass;
FIG. 10 is a side view of a vibrating mass;
FIG. 11 is a side view of a vibrating mass; and
FIG. 12 is a side view of a vibrating mass.
DETAILED DESCRIPTION
Methods and systems that implement the embodiments of the various features of the present invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the present invention and not to limit the scope of the present invention. Reference in the specification to “one embodiment” or “an embodiment” is intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least an embodiment of the present invention. The appearances of the phrase “in one embodiment” or “an embodiment” in various places in the specification are not necessarily all referring to the same embodiment. Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements. In addition, the first digit of each reference number indicates the figure in which the element first appears.
FIG. 1 is a flow chart of an embodiment of the present invention. In Step S 102 , the process to adjust the resonant frequencies of a vibrating mass begins. As shown in FIG. 2 , a surface 4 of a device layer 22 of vibrating mass 2 is patterned with a mask 6 , in Step S 104 . Mask 6 can be, for example, an etch mask such as photoresist. Device layer 22 can be connected to a supporting substrate 12 that may provide mechanical and electrical interconnection to the movable elements of vibrating mass 2 as well as to the stationary elements that serve as, for example, drive and sense electrodes. Open areas 8 can be formed in mask 6 corresponding to locations in device layer 22 where material should be removed in device layer 22 to define a device structure of vibrating mass 2 . Open areas 8 in the mask 6 can be formed by photolithographic processing.
Vibrating mass 2 can be any mass that vibrates and which has resonant frequencies that need to be adjusted. In one embodiment, vibrating mass 2 is a vibrating MEMS device such as a MEMS resonator. In another embodiment, vibrating mass 2 is a silicon MEMS resonator. In yet another embodiment, vibrating mass 2 is the vibrating element of a MEMS sensor. In still another embodiment, vibrating mass 2 is quartz. Likewise, device layer 22 can be formed from silicon in one embodiment and quartz in another embodiment. It is contemplated that vibrating mass 2 can be used in a gyroscope or any other device where vibrations are required. In one embodiment, vibrating mass 2 is used for navigation such as with vehicles, munitions, or personnel. In another embodiment, vibrating mass 2 is used for orientation sensing. Furthermore, vibrating mass 2 can be used undersea or in head tracker systems. Vibrating mass 2 can have any thickness, but in an exemplary embodiment, vibrating mass 2 has a thickness between approximately 100 μm to 600 μm.
In one embodiment mask 6 is photoresist. For example, mask 6 can be positive photoresist, negative photoresist, SU-8 photoresist, photoresist including a mixture of diazonaphthoquinone (DNQ) and novolac resin, deep ultraviolet photoresist, or any other type of resist. Mask 6 can be, for example between approximately 2 μm thick to 30 μm thick depending on the desired etch depth, etch rate, and selectivity to photoresist etching. In another embodiment, the mask may be an inorganic thin film, such as nickel, patterned by techniques such as etching or liftoff.
In Step S 106 , vibrating mass 2 is etched at device layer 22 to form trenches 10 as shown in FIG. 3 . In one embodiment, vibrating mass 2 can be etched using deep reactive ion etching. In another embodiment, vibrating mass 2 is etched using deep reactive ion etching using a time-sequenced etch and passivate chemistry, such as using sulfur hexafluoride, SF6 for the etching and octafluorocyclobutane, C4F8 for the passivation in a process commonly known as the Bosch process.
In Step S 108 , vibrating mass 2 is analyzed to determine if the resonant frequencies of vibrating mass 2 need to be adjusted and locations of vibrating mass 2 where mass should be removed from device layer 22 to achieve the desired resonant frequencies of vibrating mass 2 . For example, if vibrating mass 2 has a resonant frequency of approximately 14.950 kHz in a first axis and a resonant frequency of approximately 14.900 kHz in a second axis, then vibrating mass 2 should be adjusted to decrease the resonant frequency of the first axis by 50 Hz to bring the values for both the first axis and the second axis into conformity at a common resonant frequency of approximately 14.900 kHz.
Adjusting the resonant frequencies of vibrating mass 2 can be done, for example, by removing select amounts of mass from select locations of vibrating mass 2 . In Step S 110 , the mass removal amount of device layer 22 is determined while in Step S 112 , the mass removal location of device layer 22 is determined. In one embodiment, mask 6 remains on vibrating mass 2 when analysis of vibrating mass 2 is performed. It is contemplated that since mask 6 may be approximately 6 μm or less thick while vibrating mass 2 may be 100 μm to 600 μm thick, that disproportional distributions of mask 6 may have a negligible effect on the analysis of vibrating mass 2 . This may be especially true where it is unlikely that mask 6 will be distributed unevenly in a significant manner throughout vibrating mass 2 .
In Step S 114 , select locations of mask 6 are removed corresponding to the select locations of vibrating mass 2 as shown in FIGS. 4 and 6 . FIG. 4 is a side view of vibrating mass 2 while FIG. 6 is a top view of vibrating mass 2 . In FIGS. 4 and 6 , trenches 10 expose supporting substrate 12 . As shown in FIGS. 4 and 6 , select holes 14 are created in mask 6 corresponding to select locations where mass from device layer 22 should be removed so that vibrating mass 2 can have the desired resonant frequencies. In one embodiment, mask 6 is removed through laser ablation. It is contemplated that by using a low energy laser ablation, the amount of mask 6 that is removed can be better controlled when compared with a high energy laser ablation. Furthermore, with the use of a low energy laser ablation, it is contemplated that less debris can be created. With less debris, there is less chance that the debris will affect the operation and yield of the device. At low energies, the masking resist layer can be removed without damaging the underlying material of device layer 22 . In one embodiment, the low energy laser ablation can be performed using a laser system commonly used for trimming electronic components and reworking electronic circuits. The low energy laser ablation can have a spot size of approximately 1 μm to 10 μm, pulse energy of approximately 0.1 mJ to 2.0 mJ, and wavelengths of approximately 266 nm to 1064 nm.
Furthermore, equipment for low energy laser ablation may be cheaper, more compact and more readily available than equipment for high energy laser ablation. This can allow the low energy laser ablation equipment to be placed within a closer location to an area where steps S 104 and S 106 are performed which can lead to quicker processing and production of vibrating mass 2 with the desired resonant frequencies. This can reduce the production time for the device incorporating vibrating mass 2 and thus increase the number of devices incorporating vibrating mass 2 that are produced within a given period of time. This can also eliminate the need to remove the device from the clean production area, reducing the likelihood of introducing particulate contamination.
In Step S 116 , vibrating mass 2 is etched to remove select amounts of mass at select locations of vibrating mass 2 forming blind vias or cavities 16 as shown in FIG. 5 . In one embodiment, vibrating mass 2 can be etched using deep reactive ion etching. In another embodiment, vibrating mass 2 can be etched using deep reactive ion etching using time-sequenced etch and passivate chemistries such as the Bosch process using sulfur hexafluoride, SF6 and octafluorocyclobutane, C4F8. These cavities 16 may be of any arbitrary shape, and may include, for example, cylinders, squares, or linear trenches. After etching vibrating mass 2 , it is contemplated that the resonant frequencies of vibrating mass 2 can be adjusted to approximately the desired resonant frequencies. For example, if vibrating mass 2 originally has a resonant frequency of 14.950 kHz on the first axis and 14.900 kHz on the second axis, but vibrating mass 2 should have a common resonant frequency of 14.900 kHz on both axes, then after etching, vibrating mass 2 can have a resonant frequency of approximately 14.900 kHz on both axes. In step S 112 , the process ends.
In some cases, vibrating mass 2 may have a frequency split even after performing the steps of FIG. 1 . For example, vibrating mass 2 can have a resonant frequency of 14.9905 kHz on the first axis and 14.990 kHz on the second axis when the desired common resonant frequency is 14.990 kHz. The present invention, however, advantageously reduces the frequency split of vibrating mass 2 .
Furthermore by using the steps disclosed in FIG. 1 , it is contemplated that vibrating mass 2 can remain in a production environment or foundry throughout the entire process instead of being moved to a separate location. The minimization of movements of vibrating 2 can reduce manufacturing costs as moving vibrating mass 2 can be costly. Furthermore, the reduction of movement is beneficial in reducing the likelihood that vibrating mass 2 will be damaged during the moving process by the introduction of particulates by virtue of its removal from a clean production environment.
It is also contemplated that the steps disclosed in FIG. 1 may be advantageously used in devices where the device frequencies are testable after Step S 106 with masking layer 6 still in place and where the device can accommodate the over etch needed to remove the mass removal amount at the mass removal locations.
Although not depicted, in another embodiment, should the resonant frequencies of vibrating mass 2 still be unacceptable, any or all of step S 106 to step S 112 can be repeated. That is, if the resonant frequencies of vibrating mass 2 is 14.9905 kHz in the first axis and 14.990 kHz in the second axis then vibrating mass 2 can have more mass removed in select new additional mass removal locations with a new additional mass removal amount such that vibrating mass 2 has a resonant frequency of 14.990 kHz in both axes. However, if the new resonant frequencies are still unacceptable, then again, any or all of step S 106 to step S 112 can be repeated until vibrating mass 2 has suitable resonant frequencies. However, in subsequent applications of the process, the etching mask remains open in the original mass removal locations as well as any new mass removal locations defined. Thus, during subsequent etch processing mass will continue to be removed at the original mass removal locations as well as at the newly defined mass removal locations. This should be taken into consideration in defining the new mass removal locations and mass removal amounts.
FIG. 7 is a flow chart of an alternate embodiment of the present invention. In Step S 702 , the process to adjust the resonant frequencies of a vibrating mass begins. The process depicted in FIG. 7 begins by utilizing vibrating mass 2 which is already etched at device layer 22 to form trenches 10 and which already has mask 6 removed as shown in FIG. 8 .
In Step 706 , vibrating mass 2 is analyzed to determine if the resonant frequencies of vibrating mass 2 need to be adjusted and locations of device layer 22 where mass should be removed to achieve the desired resonant frequencies of vibrating mass 2 . For example, if vibrating mass 2 has a resonant frequency of 14.950 kHz in a first axis and a resonant frequency of 14.900 kHz in a second axis, then vibrating mass 2 should be adjusted to decrease the resonant frequency of the first axis by 50 Hz to bring the values for both the first axis and the second axis into conformity at a common resonant frequency of 14.900 kHz.
To adjust the resonant frequencies of vibrating mass 2 select amounts of mass from select locations of vibrating mass 2 can be removed. In Step S 706 , a mass removal amount of device layer 22 is determined while in Step S 708 , a mass removal location of device layer 22 is determined.
In Step S 710 , vibrating mass 2 is coated with a conformal masking material 18 as shown in FIG. 9 . Masking material 18 can be, for example, parylene. Parylene provides a vapor-deposited conformal coating that can be deposited at low process temperatures. The dry coating process avoids the issues of capillary adhesion forces and particulate contamination that are commonly associated with liquid-based processing. The conformal coating ensures protective masking of the areas that are desired to remain non-etched. Parylene can also be removed by dry processing using oxygen plasma, which facilitates removal after the process is completed. Other materials that provide complete coating of the device top surface to provide the masking under etch can similarly be used. For example, in another embodiment the masking material may be a metal film deposited by sputtering, evaporation, or atomic layer deposition (“ALD”). It is preferred that this material can be selectively removed upon completion of the process without damaging or degrading other parts of the device.
In Step 712 , select locations of masking material 18 are removed corresponding to the select locations of vibrating mass 2 as shown in FIG. 10 . As shown in FIG. 10 , select holes 20 are created in masking material 18 corresponding to select locations where mass from device layer 22 should be removed so that vibrating mass 2 can have the desired resonant frequencies. In one embodiment, insulation material 18 is removed through laser ablation. Again the use of low energy laser ablation can be beneficial compared to the use of high energy laser ablation to reduce debris, reduce the likelihood of damage to underlying material 2 , and reduce associated financial costs.
In Step 714 , vibrating mass 2 is etched to remove select amounts of mass at select locations of vibrating mass 2 forming cavities 16 as shown in FIG. 11 . In one embodiment, vibrating mass 2 can be etched using deep reactive ion etching. In another embodiment, vibrating mass 2 can be etched using deep reactive ion etching using time-sequenced etch and passivate chemistries such as the Bosch process. After etching vibrating mass 2 , it is contemplated that the resonant frequencies of vibrating mass 2 can be adjusted to approximately the desired resonant frequencies. For example, if vibrating mass 2 originally has a resonant frequency of 14.950 kHz on the first axis and 14.900 kHz on the second axis, but vibrating mass 2 should have a common resonant frequency of 14.900 kHz on both axes, then after etching, vibrating mass 2 could have resonant frequencies of approximately 14.900 kHz on both axes.
In Step 716 , the remaining masking material 18 in vibrating mass 2 is removed as shown in FIG. 12 . Masking material 18 can be removed, for example, through etching. In the preferred embodiment in which the masking material is parylene, oxygen plasma etching may be used. In step S 718 , the process ends.
It is contemplated that any or all Steps S 704 through S 716 can be repeated as necessary in order to further adjust the resonant frequencies of vibrating mass 2 .
It is also contemplated that the steps disclosed in FIG. 7 may be advantageously used in devices where the original masking layer must be removed prior to testing or where device over etch cannot be accommodated.
In one embodiment, the process described in FIG. 1 and FIG. 7 can be combined. That is, after the process in FIG. 1 is completed and the resonant frequencies of vibrating mass 2 still needs to be adjusted, etch mask 6 can be removed after step S 116 in FIG. 1 and instead of ending the process, the process can go to Step 704 with the addition of a layer of masking material 6 . Thus, the initial frequency tuning could be accomplished using the process disclosed in FIG. 1 , and subsequent fine adjustments done with the process disclosed in FIG. 7 .
Advantageously the processes described in FIG. 1 and FIG. 7 permit the frequency tuning to be accomplished at the wafer scale. This allows the wafer of tuned devices to continue wafer-scale processing, preserving the cost benefits inherent to batch processing. In particular, wafer-scale vacuum packaging is an attractive process for sealing resonator devices in an environment that allows operation with high quality factor. The processes described in FIG. 1 and FIG. 7 maintain this compatibility.
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The present invention relates to a method for adjusting the resonant frequencies of a vibrating microelectromechanical (MEMS) device. In one embodiment, the present invention is a method for adjusting the resonant frequencies of a vibrating mass including the steps of patterning a surface of a device layer of the vibrating mass with a mask, etching the vibrating mass to define a structure of the vibrating mass, determining a first set of resonant frequencies of the vibrating mass, determining a mass removal amount of the vibrating mass and a mass removal location of the vibrating mass to obtain a second set of resonant frequencies of the vibrating mass, removing the mask at the mass removal location, and etching the vibrating mass to remove the mass removal amount of the vibrating mass at the mass removal location of the vibrating mass.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to multi-layer coating apparatuses and, particularly, to a multilayer coating apparatus for delivering coating materials to a surface of an object.
2. Discussion of the Related Art
A coating apparatus is for applying a coating material onto a surface of an object. The coating apparatus is usually required to be capable of controlling a flux or other coating material flowing to the surface, a flow velocity, a relative moving velocity between the surface of the object and the coating apparatus, and a distance between the object and the coating apparatus, in order to control a thickness of the coating material formed on the object and to distribute the coating material evenly on the surface of the object. In general, in many circumstances, a plurality of layers of the various coating materials is required to be coated/formed on an object. For example, a photosensitive composite film stack usually includes nine or more layers of materials. Thus, a multilayer coating apparatus that is capable of simultaneously coating a plurality of layers of materials is demanded.
In order to improve the coating quality, many modifications have been made to the coating apparatus. For example, an unfluctuating rolling edge has been proposed to sustain a flux of the liquid flowing on the slide surface, and/or an inhaled air removal device has been devised for eliminating an excess of inhaled air brought into the coating area by the moving object.
Slide hoppers are often employed in such multilayer coating apparatuses for supplying and guiding the coating materials to flow onto a surface of an object. A conventional slide-hopper-type, multilayer coating apparatus having a slide/extrusion hopper is adapted for dispensing a liquid composition onto a moving object. Such coating apparatuses generally can be categorized into a slide-rolling-edge type and a slide-curtain type.
China Patent Application No. 01100242.5 discloses a slide rolling edge type, multilayer coating apparatus and a slide curtain type, multilayer coating apparatus. In accordance with that application and referring to FIG. 3 , the slide rolling edge type, multilayer coating apparatus 10 is illustrated. The slide rolling edge type, multilayer coating apparatus 10 includes a slide hopper 16 and a roller spindle 34 . An object 12 to be coated is wound on the outer circumference of the roller spindle 34 and is driven to jointly rotate with the roller spindle 34 . Coating materials 14 A, 14 B and 14 C are forced to flow from corresponding material containers (not shown) to corresponding cavities 18 , 20 and 22 by corresponding pumps (not shown). The coating materials 14 A, 14 B and 14 C extend breadthwise to a predetermined width. The coating materials 14 A, 14 B and 14 C are extruded through corresponding slots 24 , 26 and 28 . The coating materials 14 A, 14 B and 14 C are then combined into a multilayer composite coating material 14 on a slide surface 30 . The multilayer composite coating material 14 flows down along a projection portion 32 of the slide surface 30 , forming a rolling coating material edge 36 bounded by the projection portion 32 and the moving object 12 . Herein, an inhaled air removal device 38 is employed to remove the air brought/carried by the moving object 12 and to thereby stably sustain the rolling edge 36 . Therefore, a multilayer coating film A is formed on the moving object 12 .
FIG. 4 illustrates a slide curtain type coating apparatus 10 ′, as per the above-referenced application. The slide curtain type coating apparatus 10 ′ is similar to the slide rolling edge type, multilayer coating apparatus 10 , as illustrated in FIG. 3 . However, in the case of the slide curtain type coating apparatus 10 ′, the projection portion 32 of the slide surface is located farther away from the object 12 to be coated, when considered relative to the projection portion 32 of the slide rolling edge type coating device 10 . The multilayer composite coating material 14 falls in the form of a curtain from the projection portion 32 of the slide surface 30 to the object 12 . The multilayer composite coating material 14 is then extended to form a multilayer coating film A. A pair of guiding means 44 is disposed for guiding the falling multilayer composite coating material 14 . An inhaled air removal device 46 is disposed and configured for removing the air brought/carried by the moving object 12 and for thereby promoting the formation of an even coating on the object 12 .
The foregoing moving objects 12 to be coated may, for example, be ordinary papers, plastic films, resin half-tone papers or a composite papers, or potentially a flexible electronic substrate material. The coating materials 14 A, 14 B and 14 C generally comprise emulsion, surface-active agents, and/or viscosity enhancing agents, as well as, of course, the primary coating material(s).
However, the aforementioned multilayer composite material 14 is formed on the slide surface 30 of the slide hopper 16 prior to being coated onto the object 12 . Therefore, mutual diffusion between the coating materials 14 A, 14 B and 14 C can inevitably occur. This mutual diffusion may adversely impair the coating quality.
Accordingly, a multilayer coating apparatus and a related method are needed in the art which can avoid the potential mutual diffusion of coating materials prior to their being coated on the object.
SUMMARY
The present invention provides a multilayer coating apparatus for coating an object. The multilayer coating apparatus includes a slide hopper. The slide hopper has a main body, the main body essentially including a plurality of separate cavities for receiving coating materials, a plurality of separate slots in communication with the corresponding cavities, and a plurality of separate projection portions formed on the slide hopper. The projection portions each have a substantially sloping slide surface configured for allowing the coating material exiting from the slot to directly flow onto the object.
Compared with the conventional technologies, the multilayer coating apparatus according to the present invention delivers coating materials to the surface to be coated via a plurality of independent slide surfaces. Since these slide surfaces are independent of each other, diffusion between coating materials before they reach to the surface to be coated can mostly be avoided, thus improving coating quality.
Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Many aspects of the present coating system and the method of its use can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, the emphasis instead being placed upon clearly illustrating the principles of the present coating system and its use. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
FIG. 1 is a schematic cross-sectional view of a slide rolling edge type, multilayer coating apparatus according to a preferred embodiment of the present coating system;
FIG. 2 is a schematic cross-sectional view of a multilayer coating apparatus according to another preferred embodiment of the present coating system;
FIG. 3 is a schematic cross-sectional view of a conventional multilayer coating apparatus; and
FIG. 4 is a schematic cross-sectional view of another conventional multilayer coating apparatus.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate at least one preferred embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1 , a multilayer coating apparatus 100 according to a preferred embodiment of the present coating system is shown. The multilayer coating apparatus 100 includes a slide hopper 116 and a roller spindle 110 . An object 112 to be coated is wound on the outer circumference of the roller spindle 34 and is driven to move jointly with the roller spindle 110 . The slide hopper 116 has a main body 117 that generally includes a plurality of cavities 118 , 120 and 122 and has a plurality of slots 124 , 126 and 128 defined therein. The cavities 118 , 120 and 122 are respectively configured for accommodating coating materials 114 A, 114 B and 114 C.
The slide hopper 116 further comprises a plurality of flat projection portions 130 , 132 and 134 located on the top thereof, respectively corresponding to and communicating with the slots 124 , 126 and 128 . The flat projection portions 130 , 132 and 134 correspondingly have associated sloping slide surfaces 131 , 133 and 135 . The plurality of slots 124 , 126 and 128 are, respectively, in fluid communication with the corresponding cavities 118 , 120 , 122 . The coating materials 114 A, 114 B and 114 C can be forced to flow into the cavities 118 , 120 and 122 from corresponding containers (not shown) by flux controlling pumps (not shown). Widths of the slots 124 , 126 and 128 are advantageously equal (or at least approximately so, depending on the degree of precision required) to the width of the surface to be coated (or as the case may be, to the width of the portion of the surface desired to be coated).
The object 112 wound on the roller spindle 110 is driven to move jointly therewith. The ends of the flat projection portions 130 , 132 and 134 are preferably disposed as close as possible to the surface of the object 112 to facilitate the formation of a uniform and even coating on the object 12 . Upon being respectively extruded from the slots 124 , 126 and 128 , the coating materials 114 A, 114 B and 114 C, under a gravitational force acting thereon, flow along the corresponding slide plane surfaces 131 , 133 and 135 to the lower ends of the projection portions 130 , 132 and 134 . Thus, the coating materials flow separately prior to be coated on the object 112 . Therefore, mutual diffusion between the coating materials, prior to reaching the object to be coated, is effectively eliminated.
FIG. 2 shows a multilayer coating apparatus 100 ′ for coating an object 112 according to another preferred embodiment of the present coating system. The multilayer coating apparatus 100 ′ includes a slide hopper 140 and a roller spindle 110 . An object 112 is wound on the outer circumference of the roller spindle 34 and is driven to move jointly with the roller spindle 110 . The slide hopper 140 has a main body 142 that generally includes a plurality of cavities 118 , 120 and 122 and has a plurality of slots 124 , 126 and 128 defined therein. The slots 124 , 126 and 128 are respectively in fluid communication with the cavities 118 , 120 , 122 . The plurality of cavities 118 , 120 and 122 are respectively configured for accommodating coating materials 114 A, 114 B and 114 C.
The slide hopper 140 further comprises a plurality of curved projection portions 170 , 172 and 174 located on the top of the slide hopper 140 . These curved projection portions 170 , 172 and 174 respectively correspond to and fluidly communicate with the slots 124 , 126 and 128 . The curved projection portions 170 , 172 and 174 each have sloping curved slide surfaces 171 , 173 and 175 for guiding coating materials 114 A, 114 B and 114 C to flow toward the object 112 .
The coating materials 114 A, 114 B and 114 C are forced to flow from corresponding containers (not shown) to the cavities 118 , 120 and 122 by means of flux controlling pumps (not shown). Widths of the slots 124 , 126 and 128 are substantially equal to a width of the to-be-coated surface of the object 112 (or to the width of portion thereof to be coated, as the case may be). Guiding means 180 , 182 and 184 are additionally provided and are configured to allow the coating materials 114 A, 114 B and 114 C to smoothly flow from the projection bent slide edges 170 , 172 and 174 onto the surface of the object 112 . The object 112 is wound on and driven by a roller 110 .
Upon being extruded from the slots 124 , 126 and 128 , the coating materials 114 A, 114 B and 114 C, under the gravitational force acting thereon, flow along the corresponding slide curving surfaces 171 , 173 and 175 to corresponding lower ends of the bent slide edges 170 , 172 and 174 . Thereafter, the coating materials 114 A, 114 B and 114 C, being guided by the guiding means 180 , 182 , and 184 , fall down to the surface of the object to be coated 112 . Thus, the coating materials flow separately prior to being coated on the object 112 . Therefore, mutual diffusion, prior to reaching the object to be coated, is effectively avoided.
According to another aspect of the foregoing embodiments, the slide hoppers 116 and 140 can advantageously be made of any of various ceramic materials or ceramic-based composites, including oxide ceramics, such as Al x O y , Zr x O y , Mg 2 SiO 4 , and ZrSiO x ; nitride ceramics such as Si x N y , Ti x N y , Al x N y , and B x N y ; and carbide ceramics such as Si x C y , Ti x C y , W x C y , and Cr x C y ; and composites composed substantially of at least one of such materials. In addition, an inhaled air removal device, such as those illustrated in FIGS. 3 and 4 , may also be employed with the present embodiments of the coating system in order to remove the air brought/carried by the object 112 .
It is to be further understood that the above-described embodiments illustrate the scope of the invention but do not restrict the scope of the invention. Variations may be made to the embodiments without departing from the spirit or scope of the invention as claimed herein.
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The present coating system ( 100 ) provides a multilayer coating apparatus for coating an object ( 112 ). The multilayer coating apparatus includes a slide hopper ( 116, 140 ). The slide hopper includes a main body ( 116, 140 ), the main body essentially including a plurality of separate cavities ( 118, 120, 122 ) for receiving coating materials, a plurality of separate slots ( 124, 126, 128 ) in communication with the corresponding cavities, and a plurality of separate projection portions ( 130, 132, 134 ) formed on the slide hopper, the projection portions each having a substantially sloping slide surface ( 131, 133, 135 ) configured for allowing the particular coating material exiting from the slot to directly flow onto the object.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This Non-Provisional Application claims the benefit of co-pending U.S. Provisional Application Ser. No. 61/346,302, filed on May 19, 2010, which is incorporated herein in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to hygienic products, and more particularly, to an inexpensive finger protection device usable on public keypads and the like.
BACKGROUND INFORMATION
[0003] Store customers are routinely required to interact with public data input devices. These public data input devices include keypads, card readers, and signature capture devices used by customers at checkout counters as they pay for merchandise and services. Public data input devices also include airline check-in kiosks, bank and ATM keypads, and the like where transactions are initiated, executed, and/or completed.
[0004] The practicality and usability of the public data input devices has led to great popularity, with large numbers of customers being required to touch the same relatively small contact surfaces throughout the day. The cleanliness of these contact surfaces thus suffers. Customers inadvertently transfer dirt and illness-causing microorganisms to the public data input devices simply by using them for their intended purpose.
[0005] The fingers of the customers may be particularly unsanitary at the end of a shopping trip due to the multitude of diverse surfaces touched as items for purchase are selected. Customers shopping in the garden section may have dirt from plants or chemicals from fertilizer remaining on their hands. The hands of customers buying raw meat may come into contact with dripping juices containing dangerous (and increasingly antibiotic-resistant) campylobacter, salmonella, or other bacteria. Other customers may have a cold or other virus or may be supervising children who do. Other customers may have grease or oil on their hands from their places of business.
[0006] Currently there is no practical means or method to protect one customer from the dirt and microorganisms left on the public data input devices by the previous customers. Particularly when customers have a nick or cut on their hands, they are vulnerable to infection from common bacteria and viruses, as well as more alarming HIV, Hepatitis, herpes, blood-borne pathogens, or other infectious diseases. Placing gloves on the hand could. protect the hand, but gloves are bulky, awkward, and inconvenient. Thus a need exists for a convenient protective device.
[0007] Further, the public data input, devices may be impaired or damaged by the dirt from the customers' hands, thus necessitating repair. For example, dirt under a key of a keypad may cause that number or letter to become unfunctional. Thus a device to protect the signature capture devices, keypads, and other digital input devices is advantageous.
[0008] Additionally, many companies give inexpensive promotional items to clients or tradeshow attendees to advertise their services or products. These items may be marked with logos, slogans, the company name, or other brand-image promoting graphics. Though numerous items are available, current inexpensive promotional items have been used repetitively, thus diminishing their impact and desirability. A new inexpensive, functional item that can be marked with promotional graphics is beneficial.
[0009] Accordingly, there is an established need for a practical, convenient hygienic finger protector capable of effectively protecting customers' fingers from microorganisms and dirt and capable of protecting public data input devices from dirt from fingers, yet inexpensive enough to be provided complimentarily by companies as a advertising or promotional item.
SUMMARY OF THE INVENTION
[0010] The present invention is directed to an inexpensive, practical hygienic finger protector for protecting against contamination by dirt or microorganisms, while allowing the wearer to input data or a signature into public data input devices such as keypads, ATM PIN pads, and signature capture devices.
[0011] The hygienic finger protector preferably includes a flexible, rubber-like, tubular sheath having a proximal open end and a distal closed end. The open end is adapted to receive a human finger. The finger protector is designed to reach to approximately the first finger joint.
[0012] The finger protector further includes a knob-like protuberance imbedded into the closed end of the sheath, disposed below the downward-facing fingertip of the inserted finger. The protuberance allows a user to input his or her signature into a digital signature capture device, such as used when signing for payment by a credit card of purchases at a retail store.
[0013] Optional aspects, including a keychain attachment, embedded data storage, and aesthetic cut-outs are presented.
[0014] An object of the present invention is to provide a hygienic finger protector that protects a finger from unsanitary conditions.
[0015] A further object of the present invention is to provide a hygienic finger protector that is practical to use for inputting a digital signature in a signature capture device.
[0016] Another object of the present invention is to provide a hygienic finger protector that provides a suitable carrier for a logo or other graphic.
[0017] An additional object of the present invention is to provide a hygienic finger protector that can be customized.
[0018] These and other objects, features and advantages of the present invention will become more readily apparent from the attached drawings and from the detailed description of the preferred embodiments, which follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The preferred embodiments of the invention will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the invention, where like designations denote like elements, and in which:
[0020] FIG. 1 is a perspective view showing a first embodiment of the hygienic finger protector of the present invention as utilized on an index finger of a wearer;
[0021] FIG. 2 is a perspective view showing a first embodiment of the hygienic finger protector of the present invention;
[0022] FIG. 3 is a cut view taken along the lines 3 - 3 of FIG. 2 , showing a first embodiment of the hygienic finger protector of the present invention;
[0023] FIG. 4 is a side view showing a second embodiment of the hygienic finger protector of the present invention;
[0024] FIG. 5 is a front view showing a second embodiment: of the hygienic finger protector of the present invention;
[0025] FIG. 6 is a cut view taken along the lines 6 - 6 of FIG. 5 , showing a second embodiment of the hygienic finger protector of the present invention;
[0026] FIG. 7 is a front view showing a third embodiment of the hygienic finger protector of the present invention;
[0027] FIG. 8 is a side view showing a fourth embodiment of the hygienic finger protector of the present invention;
[0028] FIG. 9 is a side view showing a fifth embodiment of the hygienic finger protector of the present invention;
[0029] FIG. 10 is a side perspective view showing a sixth preferred embodiment of the hygienic finger protector of the present invention;
[0030] FIG. 11 is a side perspective view showing the sixth preferred embodiment of the hygienic finger protector of the present invention;
[0031] FIG. 12 is an end perspective view showing the sixth preferred embodiment of the hygienic finger protector of the present invention;
[0032] FIG. 13 is a rear side perspective view showing the sixth preferred embodiment of the hygienic finger protector of the present invention; and
[0033] FIG. 14 is a side perspective view showing the seventh embodiment of the hygienic finger protector of the present invention.
[0034] Like reference numerals refer to like parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] Shown throughout the figures, the present invention is directed toward a hygienic finger protector that is easily and quickly donned when needed for shielding the finger from dirt, contamination, and microorganisms, yet allows the wearer to directly sign a signature capture device to input a digital signature, as well as to input data into keypads, number pads, PIN pads, and the like. Further, the hygienic finger protector is inexpensive and easily imprintable, allowing usage as a carrier for logos, slogans, the company name, or other brand-image promoting graphics. Additionally, the hygienic finger protector of the present invention permits incorporation of one or more cutouts of any of a variety of shapes, permitting further customization.
[0036] Seven embodiments are presented, a first embodiment, ( FIG. 1 to FIG. 3 ), a second embodiment illustrating a fingernail-shaped cutout 27 ( FIG. 4 to FIG. 6 ), a third embodiment illustrating a customized cutout 28 ( FIG. 7 ), a fourth embodiment illustrating an indicium (such as an imprinted logo or brand-image promoting graphic 33 ) and a keychain attachment 30 ( FIG. 8 ), a fifth embodiment illustrating an embedded data storage device 35 ( FIG. 9 ), a contoured sixth preferred embodiment, ( FIG. 10 to FIG. 13 ), a contoured seventh embodiment with a fingernail-shaped cutout 27 ( FIG. 14 ).
[0037] Referring now to FIG. 1 , a hygienic finger protector, shown generally as reference number 10 , is illustrated in accordance with a first embodiment of the present invention, as being utilized on a wearer's index finger for directly signing a signature capture device 11 or for inputting data into the number Pad 12 . As shown, the hygienic finger protector 10 comprises a tubular sheath 20 and a knob-like protuberance 25 embedded within the tubular sheath 20 .
[0038] The tubular sheath 20 has a proximal open end 21 , has a distal closed end 29 , and has a sheath wall 23 of an adequate thickness to retain embedded knob-like protuberance 25 . The distal closed end 29 is cone-shaped with a somewhat elongated tube extending to open end 21 . The tubular sheath 20 is sized and configured to receive a human finger (generally an index finger). When inserted, the fingertip generally abuts the closed end 29 . The proximal open end 21 is configured with a finger-receiving opening sized to allow a fingertip to be inserted.
[0039] The hygienic finger protector may be offered in multiple sizes to accommodate fingers of differing sizes (such as, small, medium, and large), with the tubular sheath 20 varying both in length and in diameter of the open end 21 . Preferably the tubular sheath 20 is configured to reach to approximately the first joint of the finger, though variations in length are within the scope of the invention.
[0040] The sheath wall 23 is preferably formed of a natural or man-made rubber-like material. The rubber-like material is thicker than commonly available latex finger cots, thereby increasing strength and durability. Also, the rubber-like material is sufficiently thick ( FIG. 2 , FIG. 3 ) to retain the embedded knob-like protuberance 25 within the sheath wall 23 . Optionally, the sheath wall 23 may be formed of a rigid plastic, flexible plastic, or a combination of rigid plastic and flexible plastic. For example, the distal end may be formed of a rigid plastic with the protuberance 25 formed unitarily with the distal end, with a flexible plastic proximal portion non-removably joined to the rigid plastic distal portion. Or, alternatively, the entire sheath wall 23 could be formed integrally with the protuberance 25 of a rigid plastic. Preferably the sheath, open end 21 , and closed end 29 are formed of flexible, rubber-like material with the protuberance 25 formed of a more rigid plastic.
[0041] The knob-like protuberance 25 is preferably a spheroidal or ovoidal bead of plastic, with the plastic having a sufficient rigidity to impress a signature into a signature capture device. The protuberance 25 is adapted to be pressed against the signature capture device to create a focus of pressure satisfactory to input the signature. Optionally, the protuberance 25 may be formed of metal, may be magnetized, or have the operative properties of an electromagnetic pen meeting the standard specifications for electromagnetic pens used with electronic signature pad sensors to create a digital signature.
[0042] The protuberance 25 is located in a downward-facing position toward the closed end 29 , situated under the fingertip of the wearer for convenience of inputting a signature. Protuberance 25 may be approximately ⅛ to ⅜ inches in diameter, as illustrated. During manufacture the knob-like protuberance 25 may be placed and positioned in the viscous rubber-like material before hardening.
[0043] Referring now to FIG. 4 to FIG. 6 , the second embodiment of the hygienic finger protector 10 provides a fingernail-shaped cutout 27 configured to allow the nail of the wearer to be displayed through cutout 27 and configured to accommodate longer nails, artificial nail tips, fashion nails, nail enhancements, or nail extensions. The cutout 27 allows the display of nail polish and nail art designs.
[0044] The third embodiment of FIG. 7 illustrates a customized cutout 28 . The customized cutout 28 provides a high degree of adaptability to current trends and marketing needs, allowing customization for particular companies (via logos or other brand-image promoting shapes) and/or for timely retail sales (seasonal shapes).
[0045] Cutout 27 and cutout 28 may be cut or trimmed after fabrication of sheath 20 or sheath 20 may be molded with cutout 27 , 2 $ formed unitarily.
[0046] The fourth embodiment illustrates the utilization of printing to customize the hygienic finger protector 10 . The sheath 20 is imprinted with indicium or indicia 33 , such as a desirable, marketable graphic. The marketable graphic 33 is designed to increase the desirability and personalization of the hygienic finger protector 10 . For example, the indicium 33 may be artwork; a slogan, saying, or other text; or a company-related image, logo, or other brand-image promoting graphic.
[0047] Optionally, cutout 27 or customized cutout 28 may be utilized with the imprinting of the brand-image promoting graphic, indicium 33 .
[0048] The fourth embodiment of FIG. 8 further includes an extended bulge 30 or thickened region of sheath 23 having an aperture 38 configured to receive a key ring or keychain 31 . The aperture 38 may be simply an opening in the extended bulge 30 or, for more durability, may have a grommet embedded into extended bulge 30 with a center aperture to receive a key ring or keychain 31 .
[0049] The fifth embodiment of FIG. 9 illustrates an embedded data storage device 35 . The embedded data storage device 35 is operable to store data and, in some aspects, to transmit data. The data storage device 35 may be a bar code, RFID tag (radio frequency identification label generally configured with a integrated circuit to store and process data and to modulate and demodulate a radio-frequency signal and configured with an antenna), a keycard (configured to store a digital signature), a smart card (operable to process data by way of an integrated circuit and to receive input and deliver output), or the like.
[0050] The embedded data storage device 35 allows enhanced customization. The embedded data storage device 35 can be configured to supply identification information. For example, the stored data may be a preferred shopper number to allow the customer wearing the hygienic finger protector to obtain discounts or the stored data may designate a group affiliation, such as allowing the customer to be identified with a particular school for enabling school rewards.
[0051] FIG. 10 to FIG. 13 illustrate the sixth embodiment of the hygienic finger protector 10 , which includes a contour 26 of sheath 20 and a raised rim 36 . An alternate keychain attachment 30 is also shown. The keychain attachment 30 has an interior aperture 38 sized and configured for receiving a keychain, a ring, a cord, a cable, or the like.
[0052] The contour 26 is a curved shape that allows the distal end 29 of sheath 20 to generally conform to the shape of a typical fingertip. The incorporation of the contour 26 reduces or prevents rotation of the finger protector 10 with relation to the inserted fingertip. The contour 26 may include both an interior contour and/or an exterior contour.
[0053] The raised rim 36 is a circumferential rounded rim at the edge of proximal open end 21 . The raised rim 36 provides a smooth entrance for the fingertip, allowing quick and easy insertion. Allowing the finger protector 10 to be quickly donned provides an advantage in rushed situations, such as when ready to sign a digital signature pad or input a PIN number at a busy store checkout counter. Additionally, the raised rim 36 provides an aesthetically pleasing,finished appearance for the edge. Optionally, the raised rim 36 or other portion of the sheath may be formed in a second color to enhance the appeal of the finger protector 10 .
[0054] FIG. 14 illustrates the seventh embodiment of the present invention, which incorporates the features of the sixth embodiment and adds a cutout rim 34 . The cutout rim 34 is a rounded rim at the edge of cutout 27 . Similar to the circumferential raised rim 36 , the cutout rim 34 provides a smooth, pleasing finished appearance for the edge. Preferably both the circumferential raised rim 36 and the cutout rim 34 are unitarily molded with sheath 20 .
[0055] To use the hygienic finger protector 10 , the customer inserts his finger (generally the index finger) into the sheath 20 until the tip of the finger abuts the distal closed end 29 of sheath 20 . The finger, covered by the hygienic finger protector 10 , may be used to input numbers into the keypad. 12 (such as PIN numbers, phone numbers, etc.). Optionally, the protuberance 25 may be pressed against the signature capture device 12 and moved to create a signature. The finger is thus protected from dirt and bacteria and viruses (such as, for example, HIV, Hepatitis, herpes, blood-borne pathogens, and other infections) that contaminate the keypad. 12 or signature capture device 11 . Also, the keypad 12 and signature capture device 11 are protected from dirt from customers' hands, which may lead to less maintenance and cleaning, saving employee time and reducing costs.
[0056] Companies may choose to customize the hygienic finger protector 10 and to provide the customized finger protectors 10 to clients and customers to create goodwill, brand recognition, and the like. Due to the low cost per hygienic finger protector 10 , they may advantageously be used as complimentary promotional items to give to tradeshow attendees to advertise services or products.
[0057] Since many modifications, variations and changes in detail can be made to the described preferred embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative, and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents.
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An inexpensive, practical hygienic finger protector is provided, which includes a tubular sheath having a proximal open end and a distal closed end. The open end is adapted to receive a human finger to approximately the first joint with the tip of the finger, when inserted, abutting the closed end. The finger protector further includes a knob-like protuberance imbedded into the closed end of the sheath, disposed below the downward-facing fingertip of the inserted finger. The finger protector guards against contamination by dirt or microorganisms, while allowing the wearer to input data or signatures into public data input devices such as keypads or s keypads, card readers, and signature recorders. Optionally aspects, including a keychain attachment, embedded data storage, and aesthetic cut-outs are presented.
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BACKGROUND OF THE INVENTION
This invention relates to the preparation and utilization of a unique use for a drilling fluid for use with rotary drilling and more particularly for use with horizontal drilling where drill pipe slides into a borehole with a downhole motor used for rotation of the drill bit the drilling fluid utilizing an oil in water emulsion prepared from water, oil, and an emulsifier. The external phase of the emulsion is water and can be a variety of source waters. The internal phase is oil which amounts to more than 50 percent by volume of the drilling fluid. The oil can be a variety of oils such as crudes, diesels, vegetable oils, poly alpha olefins, etc. The emulsifier is prepared from blending a mixture of alcohol ether sulfates, polyols, and sodium resinates derived from wood resulting in a drilling fluid with improved high temperature stability, and elevated yield points which are easily controllable.
The term "STABLE MUL" will be used throughout this disclosure as referring to the water external oil in water micellar dispersion drilling fluid which is the subject of this application.
Well drilling operations have been shown to be improved by the use of various micellar emulsions. The prior art is replete with drilling fluids utilizing various emulsifying agents.
U.S. Pat. No. 4,536,297 to Loftin el. al. discloses a drilling fluid composed of water, viscosity enhancer, fluid loss reducer, rheology stabilizer, and a water soluble clay-stabilizing organic salt.
U.S. Pat. No. 3,760,892 to Walker discloses a drilling fluid and method of use comprising an aqueous dispersing agent.
U.S. Pat. No. 3,561,548 to Mondshine discloses an emulsion drilling fluid and method for adjusting the osmosity of the aqueous phase of a drilling mud by using inorganic salts so that the mud aqueous phase osmosity equals the aqueous interstitial fluid osmosity.
U.S. Pat. No. 3,558,545 to Lummus discloses a low solids drilling fluid utilizing a pair of polymers use as flocculating agents for clays.
U.S. Pat. No. 3,699,042 to Browning, et. al. discloses a drilling fluid and process comprising an aqueous phase thickening agent, an organic polyelectrolyte ligand and a transition metal component.
U.S. Pat. No. 3,734,856 to Son discloses an oil external micellar dispersion formulated from a petroleum sulfonate emulsifier.
These prior inventions and numerous others offer significant advances in drilling mud technology, however there has never been developed an oil in water drilling fluid which contains at least 50 percent by volume oil in the internal phase while also withstanding high temperatures and providing high yield points, low gel strengths and ultra low fluid loss values.
The applicant has found that use of the STABLE MUL system as a drilling fluid as disclosed provides a fluid with elevated yield points and low gel providing ideal properties for drilling, coring, workover, and completion of wells.
In rotary and horizontal drilling of wells, a string of drill pipe having a drill bit and a bottom hole assemble mounted on the lower end thereof is rotated to cause the bit to create the borehole. A drilling fluid circulated down through a continuously rotating hollow drill string must provide sufficient lubricity, yield point, and thermal stability, in addition to not damaging formation zones. It is most preferable that the drilling fluid allow the drill string to be operated continuously without interruption to maximize the drilling operation economics. The present invention is intended to provide a process for drilling a well utilizing a drilling fluid which accomplishes these objectives.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a method a drilling a well using a water external micellar dispersion for use as a drilling fluid on rotary drilling operation and which is exceptionally useful in horizontal drilling operations.
It is a further object of the invention to provide an oil in water micellar dispersion drilling fluid which can withstand high temperatures and which has more than 50 percent oil by volume in the internal phase.
It is a further object of the present invention to provide an oil in water micellar dispersion drilling fluid which has more than 50 percent by volume oil in the internal phase while also remaining stable at elevated temperatures of about 375° F. and also providing high yield points, low gel strengths, and ultra low fluid loss values.
It is a further object of the invention to provide an oil in water micellar dispersion drilling fluid system which allows for easy control and maintenance of the drilling fluid yield point by either adding more oil or water to the fluid either before or during drilling operations.
It is a further object of the invention to provide an oil in water micellar dispersion drilling fluid which demonstrates excellent cleaning capacity of the borehole during drilling of the well and no observed packing-off during drilling operation or settling when out of the hole.
It is a further object of the present invention to provide an oil in water micellar dispersion system for use as a drilling fluid which drilling fluid weighs as low as 7.2 pounds per gallon for easy use upon under-pressured zones.
It is a further object of the present invention to provide an oil in water micellar dispersion for use as a drilling fluid which provides excellent lubricity properties thereby decreasing buildup of torque and drag particularly when sliding a downhole motor said dispersion further decreasing borehole washout, stuck pipes, and fill on bottom.
It is a further object of the present invention to provide an oil in water micellar dispersion for use as drilling fluid which demonstrates stable flow and rheology characteristics when exposed to elevated temperatures above 350° F.
It is a further object of the present invention to provide an oil in water micellar dispersion system for use as a drilling fluid which demonstrates ultra low fluid loss and also acts as a well stimulation fluid.
It is still a further object of the present invention to provide an ecologically safe oil in water drilling fluid system which utilizes ecology safe oils such as canola, palm, caster, soy bean, tung, and poly alpha olefins, etc.
It is still another object of the present invention to provide a drilling fluid emulsion system having an oil/water ratio of at least 70 percent oil and 30 percent water.
It is another object of the present invention to provide a drilling process utilizing a drilling fluid which provides a return of permeability rather than damaging permeability in the production zone.
Applicant's water external micellar dispersion drilling fluid contains between 50 and 90 percent by volume hydrocarbon fluid or oil, between 1 and 10 percent by volume emulsifier, and about 10 to 50 percent by volume water. The resulting emulsion may contain weighting materials such as calcium carbonate, barite, iron oxide, and combinations of such materials. Additionally, the resulting emulsion may contain water phase thickening agents such as high molecular weight sodium poly acrylamide, hydroxyethyl cellulose, and zanthan gums. Furthermore, the water phase may contain organic and inorganic salts. The emulsifier system also contains water soluble resins, alcohol ether sulfonates, and polyols.
DESCRIPTION OF THE INVENTION
While the present invention will be fully described it is to be understood at the outset that persons skilled in the art may modify the invention herein described while still achieving the desired result of the invention. Accordingly, the description which follows is to be understood as a broad informative disclosure directed to persons of skill in the appropriate arts and not as limitations upon the present invention.
The STABLE MUL system is composed of an external water phase and an oil internal phase utilizing an emulsion system comprising alcohol ether sulfonates blended with a polyol and water soluble resonates made from wood resins.
The STABLE MUL system components are premixed with water prior to addition of any hydrocarbon fluids. The water soluble wood resonates made from wood are supplied from Hercules under the tradenames "DRESENATE-TX" and "VINSOL-NVX" and are supplied as the sodium salts of the water soluble resonates. The wood resonates amount to about 14 percent by volume of the premixed emulsion and are added to an amount of water which water amounts to about 55 percent by volume of the total premixed emulsion. Next a product sold by Witco under the tradename "FOAM 3-X" which is an alcohol ether sulfonate blended with a polyol of molecular weight of about 2000 is added to the premix amounting to about 32 percent by volume of the total premixed emulsion. Care should be exercised in the mixing stage of the Witco product to prevent excessive foaming. The preferred concentration of the chemical ingredients of the premixed emulsion should be about 45 percent while the water should be about 55 percent. The premixed emulsifier system is then canned out or drummed out to be shipped to the oilfield for use in making an oil in water emulsion for drilling wells.
In the oilfield the STABLE MUL system is prepared for use as a drilling fluid by first drawing up an amount of water which will result in a final product of about 30 percent water by volume. The premixed emulsion is added to the water at about 20 pounds of premixed emulsion per barrel of final product desired. The amount of the premixed emulsion added can range between 10 and 30 pounds per barrel of final product desired. To the water/emulsion mixture is added the desired hydrocarbon fluid which should amount to about 70 percent by volume of the final product desired. The volume of hydrocarbon fluid can also vary between 50 and 90 percent of the final product.
The water used can be from a variety of sources including brine water, brackish water, and soft water. The hydrocarbon fluid can is most preferable diesel however other oils are suitable including canola oil, soy bean oil, rape seed oil, other vegetable oils, palm oil, caster oil, tung oil, mineral oils, crude oils, and poly alpha olefins.
The emulsion system is controlled or adjusted in the field by adding either water, hydrocarbon fluid or STABLE MUL system emulsion. When hydrocarbon fluid is added to the 70 percent oil emulsion system the yield point increases, while addition of water to the 70 percent oil emulsion system reduces the yield point. Table 2 illustrates the rheology of the emulsion system at varying oil/water ratios. As illustrated in Table 2 the emulsion system gel strength is also controllable by varying oil/water ratios.
The emulsion fluid also experiences ultra low fluid loss which results in borehole wall protection from enlarging during drilling and no shale problems have been observed using the emulsion system. Additionally, permeability studies have demonstrated the positive effects from the use of the emulsion system as compared to other drilling mud systems. Table 3 illustrates return permeability studies indicating a 110 percent return for the STABLE MUL emulsion system, as compared to other drilling mud systems.
The STABLE MUL system also exhibits thermal stability even up to 350° F. Table 4 illustrates rheology for the STABLE MUL system at various temperatures both before and after hot rolling.
Table 1 illustrates the STABLE MUL systems stability at various concentrations of solids and compares the rheology and filtrate of STABLE MUL at different concentrations of solids with heat aging. It is contemplated that solids may be removed from the STABLE MUL system using known solid removal equipment, thus recovering the STABLE MUL system for reuse.
The density of the STABLE MUL system can be varied between 7.2 pounds per gallon and above 12 pounds per gallon by the addition of various weighting agent already known to the art including calcium carbonate, barite, and iron oxides.
Aqueous phase viscosity enhancing agents may also be employed for use with the STABLE MUL system such as high molecular weight sodium polyacrylamide, hydroxyethylcellulose, or zanthan gums.
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The use of a water external micellar dispersion as a drilling fluid for rotary and horizontal drilling operations wherein the drilling fluid contains more than 50% oil in the internal phase, improved high temperature stability, high yield points, low gel strengths, and ultra low fluid loss.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is the U.S. National Stage of International Patent Application No. PCT/CA2009/001228 filed on Sep. 4, 2009, the disclosure of which is hereby incorporated by reference in its entirety.
FIELD
The present invention relates generally to computer data processing systems and more specifically relates to a computerized method and system for compiling electronic identifiers.
BACKGROUND
When properly executed, surveys can be an immensely valuable tool in a wide variety of endeavours, including social sciences, marketing, customer relationships, and political polling. Other endeavours that benefit from surveys can also be enumerated.
A completely accurate survey would of course involve every member of a relevant target group. However, such breadth is often impractical and surveying techniques have been developed whereby only a sample of the relevant target group need take the survey. If the sample is of a sufficient size, and sufficiently random, then the results of the survey can have a high degree of accuracy in reflecting the results of the survey were the entire target group to take the survey. Computerized methods and systems can further assist in the accuracy and speed of taking such surveys.
SUMMARY
An aspect of the specification provides a computing engine comprising: at least one processing unit; at least one storage unit connected to the at least one processing unit; at least one public switched telephone network (PSTN) gateway connected to the at least one processing unit; the PSTN gateway configured connect to a plurality of plain old telephone system (POTS) terminals via the PSTN; at least one Internet gateway connected to the at least one processing unit; the Internet gateway configured connect to a plurality of computing clients via the Internet; the processing unit configured to perform a random connection to at least one of the POTS terminals and to receive an electronic address associated with at least one of the computing clients.
The electronic address can be an email address.
The processing unit can be configured to receive a set of telephone numbers corresponding to at least a portion of the POTS terminals, and the processing unit can be configured to randomly select a POTS terminal from the set in order to perform the random connection.
The processing unit can be configured to perform a plurality of random connections to different POTS terminals and to receive a plurality of electronic addresses corresponding to each of the POTS terminals.
A number of the plurality of random connections can correspond to a sample size determined according to a survey design.
The processing unit can be further configured to validate the electronic address. The validation can be implicit. The validation can also explicit whereby the processing unit addresses a query to the electronic address; the query including a request for a response having a predefined expected contents. The predefined expected contents can correspond to a password that was provided as part of completing the random connection.
The processing unit can be configured to generate a voice message at the at least one of the POTS terminals, the voice message requesting provision of the electronic address.
Another aspect of the specification provides a computing engine comprising at least one processing unit; at least one storage unit connected to the at least one processing unit at least one first-type communication gateway connected to the at least one processing unit; the first-type communication gateway configured connect to a plurality of first-type communication terminals via a first network; at least one second-type communication gateway connected to the at least one processing unit; the second-type communication gateway configured connect to a plurality of second-type communication terminals via a second network; the processing unit configured to randomly connect to at least one of the first-type communication terminals and to receive an address corresponding to at least one of the second-type communication terminals.
Another aspect of the specification provides a computerized method for randomized compilation of electronic addresses comprising: via at least one processing unit, performing a random selection of one of a plurality of plain old telephone system (POTS) terminal addresses associated with a public switched telephone network (PSTN); via the at least one processing unit, controlling a PSTN gateway interconnecting the processing unit and the PSTN to establish a connection with the one of the POTS terminal addresses; via the at least one processing unit, sending an electronic message representing a request to provide an electronic address associated with at least one of a plurality of computing clients that are connected to a data network; via the at least one processing unit, receiving the electronic address associated with the at least one of a plurality of computing clients that are connected to the data network; via the at least one processing unit, storing the electronic address associated with the at least one of a plurality of computing clients in a storage device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of a system for randomized compilation of electronic identifiers.
FIG. 2 is a flowchart depicting a method for randomized compilation of electronic identifiers.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Referring now to FIG. 1 , a system for randomized compilation of electronic identifiers is indicated generally at 50 . System 50 comprises a computing engine 54 , which itself comprises a processing unit 58 that interconnects volatile storage 62 and non-volatile storage 66 . Engine 54 also comprises a first communication gateway 70 connected to processing unit 58 , and a second communication gateway 74 also connected to processing unit 58 . System 50 also comprises an administration terminal 78 that connects to processing unit 58 . Administration terminal 78 is configured to provide input to processing unit 58 via a keyboard or mouse or other input device, and also configured to generate output from processing unit 58 via a display or other output device.
Engine 54 can be implemented as a single server, or an array of servers, based on any well-known computing environment(s) including a module that houses one or more central processing units, volatile memory (e.g. random access memory), persistent memory (e.g. hard disk devices) and network interfaces. For example, engine 54 can be a Sun Fire V480 running a UNIX operating system, from Sun Microsystems, Inc. of Palo Alto Calif., and having four central processing units each operating at about nine-hundred megahertz and having about sixteen gigabytes of random access memory. However, it is to be emphasized that this particular server is merely exemplary, and a vast array of other types of computing environments, or array of computing devices, for engine 54 is contemplated. Furthermore, various functions within each engine 54 can be divided out amongst different servers.
System 50 also comprises a first communication network 82 that connects to a plurality of first-type communication terminals 86 - 1 , 86 - 2 . . . 86 - n . (Generically, first-type communication terminal 86 , and collectively, first-type communication terminals 86 ). A backhaul link 90 connects network 82 to first communication gateway 70 .
System 50 also comprises a second communication network 94 that connects to a plurality of second-type communication terminals 98 - 1 , 98 - 2 . . . 98 - n . (Generically, second-type communication terminal 98 , and collectively, second-type communication terminals 98 ). A backhaul link 102 connects network 94 to second communication gateway 74 .
In a present exemplary embodiment, first-type communication terminals 86 are plain old telephone service (POTS) telephones and network 82 is the public switched telephone network (PSTN). Also in the present exemplary embodiment, second-type communication terminals 98 are desktop or laptop computing devices with email and web-browsing functionality and network 94 is the Internet.
Of note is that each first-type communication terminals 86 and POTS network 82 reflect a communication system characterized by an addressing scheme that is finite and predictable. For example, in North America, POTS telephones have standard ten-digit telephone number of the form “XXX-XXX-XXXX”. Such a scheme is finite as the ten-digit number will always fall within the range of zero through 9,999,999,999 even if not all of those numbers are actually used. Accordingly there are is a total of “n” possible first-type communication terminals 86 , where n has a theoretical maximum of 9,999,999,999.
In contrast, each second-type communication terminal 98 and Internet 94 reflect a communication system that is characterized by an addressing scheme that is infinite and not predictable. For example, each second-type communication terminal 98 may have an email client application associated with an email address of the form AAAA@BBBBB.CCC. Note that none of the fields in the email address need have a consistent number of characters and therefore there are potentially an infinite number of possible email address combinations. Accordingly there are total of “o” possible second-type communication terminals 86 , where o has no theoretical maximum at all.
System 50 also comprises an external database 104 that is connectable to processing unit 58 via network 94 , link 102 and gateway 74 . External database 104 is configured to maintain a list of addresses for each first-type communication terminal 86 .
Referring now to FIG. 2 , a method for randomized compilation of electronic identifiers is represented in the form of a flow-chart and indicated generally at 200 . Method 200 can be performed using system 50 , and hereafter method 200 will be explained with reference to system 50 . It should be understood however that system 50 or method 200 or both can be modified.
At block 205 , a first set of addresses is received. In system 50 , block 205 is effected by processing unit 58 , which receives electronic data representing a finite set of addresses. In the present embodiment the finite set of addresses represent some or all of the addresses for each first-type communication terminal 86 . The data can be manually entered via terminal 78 , or received from external database 104 . When the data is received at processing unit 58 , it can also be locally stored in persistent storage 66 for further use.
In a present embodiment, the set of addresses can be selected to correspond with only a portion of first-type communication terminals 86 . In the context of delivering surveys, the portion of first-type communication terminals 86 can be selected based on a geographic region where it is known that first-type communication terminals 86 are expected to be located. Again, referring to the North American region, it can be desired to only include those first-type communication terminals 86 that are located in Canada, in which case the set of addresses received at block 205 can be restricted to addresses that correspond to first-type communication terminals 86 located in Canada. By the same token, it can also be desired to restrict the set of addresses received at block 205 to a particular sub-type. For example, many POTS telephone numbers are assigned to non-POTS networks, such as wireless telephony communication devices or Voice over Internet Protocol (VOIP) devices. Accordingly, the set of addresses received at block 205 can be restricted to land-line communication terminals 86 that are based on POTS. It will now be apparent that other criteria can be used to select only particular sets of addresses at block 205 .
At block 210 , a desired sample size is received, and represented further herein as variable “a”. The number “a” can be equivalent to the total number of addresses received at block 205 . More typically, the number “a” is smaller, and possibly much smaller, than the total number of addresses received at block 205 . Where method 200 is being used in relation to administration of a survey, then the number “a” can be set to correspond to a survey sample size that is established during the design of the survey. Of course, when the number “a” is greater, so too is the confidence in the results of the survey.
At block 215 , a counter is set to zero such that subsequent cycles through the remaining steps of method 200 can be tracked in relation to the desired sample size “a”.
At block 220 , an address is randomly selected from the address set. Various random number generation operations can be used by processing unit 58 to effect block 220 . Generally, it is desired to select a high-quality operation that, as much a possible, produces a truly random result. Examples of random number generation operations are discussed further below. Assume, for example, that as a result of block 220 that the address for first-type communication terminal 86 - 1 is selected.
At block 225 communication is initiated with a first-type communication terminal 86 that corresponds to the address selected at block 220 . In this example, first-type communication terminal 86 - 1 . To effect block 225 , processing unit 58 controls gateway 70 so as to dial the POTS telephone number associated with first-type communication terminal 86 - 1 and wait for confirmatory signals from network 82 that this communication has been successfully initiated.
Gateway 70 can be configured with an auto-dialer to perform block 225 . Where a ‘busy-signal’ is received then gateway 70 can be further configured to periodically redial. Likewise, where there is a ring-back signal, but no answer, then gateway 70 can also be configured to attempt to periodically redial a predefined number of times.
At block 230 , a determination is made as to whether a successful connection has been made. In this specific example, processing unit 58 and gateway 70 can be configured to ascertain whether a connection with first-type communication terminal 86 - 1 was successful. For example, a “no” determination will be reached where a busy signal, or “no answer” is consistently received despite attempting to redial for the predefined number of times. A “no” determination can also be reached where network 82 sends a signal indicating that the number is not actually connected.
If a “no” determination is made at block 230 , then at block 235 the counter from block 215 is left unchanged, and at block 240 the address selected at block 220 is removed (or flagged for such) from the set of addresses originally received at block 25 .
At block 245 a determination is made as to whether or not there are any remaining addresses in the set received at block 205 . A “no” determination leads to an exception block 250 (e.g. where an error message is generated on terminal 78 ) and method 200 ends. A “yes” determination at block 245 returns method 200 to block 220 at which point another address is randomly selected from the remaining set of addresses. In other words, the address removed at block 240 is no longer a possible result during the performance of block 220 .
Returning now to block 230 , if a “yes” determination is made at block 230 then method 200 advances to block 255 . A “yes” determination would typically be reached when a signal is received via network 82 that first-type communication terminal 86 - 1 has been answered.
At block 255 , a request is sent for a secondary address. In system 50 , block 255 is typically effected by processing unit 58 generating an audio-message that was previously stored in storage 66 which requests the provision of an address associated with a second-type communication terminal 98 . In a present embodiment, the address that is requested is preferred to be an address that operated by the answerer at block 255 . Assuming that first-type communication terminal 86 - 1 and second-type communication terminal 98 - 1 are operated by one answerer, then the address that is requested would be an address that is associated with second-type communication terminal 98 - 1 .
Optionally, at block 255 , further steps can be taken to try and verify that the answerer of terminal 98 - 1 actually owns or otherwise has control over terminal 98 - 1 . For example, a message can be played inquiring if the answerer owns or otherwise has such control, with responses gathered via interactive voice response (IVR) technology. As a further enhancement at block 255 , IVR technology can be employed to select a language that is preferred by the answerer, and then the request for the secondary address can be made via such language.
At block 260 , a response is received to the request made at block 255 . The form in which the response is received is not particularly limited. The response can be received via terminal 86 - 1 and can be via voice, or via entry of a sequence of dual-tone-multi-frequency DTMF key presses on terminal 86 - 1 . The response can also be via terminal 98 - 1 , where an email or other electronic signal is sent directly from terminal 98 - 1 to processing unit 58 indicating the association between terminal 86 - 1 and terminal 98 - 1 .
Where the received response is via voice, sent through terminal 86 - 1 to processing unit 58 , then processing unit 58 can additionally be configured with a voice-to-text module that converts the voice representation of the received address into an American Standard Code for Information Interchange (ASCII) format or a similar code that can then be used to generate a string of numbers or text or both which can be used to address communication terminal 98 - 1 directly through network 94 . Another option is that an operator of terminal 78 listens to the voice representation, either a recording or in real time, and manually enters the string of numbers or text or both which can be used to address communication terminal 98 - 1 directly through network 94 .
Where the received response is via DTMF, then likewise the DTMF signals are decoded by processor 59 into a string of numbers or text or both which can be used to address communication terminal 98 - 1 directly through network 94 .
Where the received response is via terminal 98 - 2 , then the response will typically inherently be string of numbers or text or both which can be used to address communication terminal 98 - 1 directly through network 94 . Additionally, however, if the response is receive via terminal 98 - 1 then a verification process can be employed to validate the correspondence between terminal 86 - 1 and terminal 98 - 1 . For example, a unique web-site address hosted by processing unit 58 , combined with a unique password that is provided as part of the request at block 255 can be employed. Thus, terminal 98 - 1 can be used to access the web-page hosted by processing unit 58 , and the web-page can prompt for entry of the POTS number associated with terminal 86 - 1 , as well as the unique password that was provided at block 58 , thereby validating the association between terminal 86 - 1 and terminal 98 - 1 .
The type of address that is received at block 260 is not particularly limited. For example, email addresses would be a common type of address received at block 260 which would reflect an association with an appropriate terminal 98 . Other examples include instant message addresses or social networking web-site identities.
At block 265 , the address received at block 265 is validated. The validation can be implicit or explicit or both. An implicit validation of an email address can be based on a determination as to whether or not the email address is properly formed, generally corresponding to the format of AAAA@BBBBB.CCC. For example, the absence of an “@” symbol, or the presence of multiple “@” symbols, provides an indication that the address is not properly formed and therefore implicitly the received address will fail validation at block 265 .
An explicit validation at block 265 can include sending a communication from processing unit 58 that is addressed to the address that is received at block 260 (i.e. terminal 98 - 1 ), and then waiting for a response from that address. Again, using the specific example of email, an email can be sent from processing unit 58 to terminal 98 - 1 via network 94 that asks the email-recipient to provide data-input representing a confirmation. Such a confirmation could include a confirmation that in fact terminal 98 - 1 is associated with terminal 86 - 1 . The confirmation could also include a password or other unique data string that was initially provided at block 255 via terminal 86 - 1 , whereby such a password would be received at terminal 98 - 1 and sent to processing unit 58 to complete the validation.
In a present embodiment, a “no” determination at block 265 causes method 200 to return to block 235 , and then to block 240 , ultimately leading back to block 220 or to an exception at block 250 , as previously described. (In a variation, a “no” determination could also include one or more attempts to retry request for the secondary address by re-cycling one or more times through blocks 255 , 260 and 265 rather than immediately returning to block 235 from block 265 on a validation failure at block 265 ).
A “yes” determination at block 265 causes method 200 to advance to block 270 , at which point an association is made between address selected at block 220 , and the address received at block 260 . In the specific example above, processor 54 can effect block 270 by storing an entry in a database that identifies a relationship between the address selected at block 220 (e.g. terminal 86 - 1 ) and the address received at block 260 (e.g. terminal 98 - 1 ).
At block 275 , a connection is initiated with the address associated with the communication terminal received at block 260 . Such a communication can include a further email or other type of electronic communication that is between processor 54 and terminal 98 - 1 . In the survey example, it is contemplated that block 275 can include the initiation of the administration of a survey via terminal 98 - 1 , and utilizing the interactive hardware functionality of terminal 98 - 1 .
At block 280 , a determination is made as to whether the communication initiated at block 275 was successful. If the survey being administered is not completed, or not responded to, then a “no” determination would be made at block 280 . However, a successful completion of the survey leads to a “yes” determination at block 280 .
At block 285 , the counter initiated at block 215 is incremented (i.e. b=b+1) and at block 290 a determination is made as to whether the desired sample size has been fulfilled (i.e. is b<a?). If the desired sample size has not been fulfilled, then method 200 advances to block 295 at which point the counter initiated at block 215 is incremented by one (i.e. b=b+1) and then method 200 returns to block 240 , which has been previously described.
If a “no” determination is made at block 290 (i.e. the desired sample size is fulfilled), then method 200 ends with the successful completion of the survey.
Variations are contemplated. For example in method 200 , the counter can be omitted in favour of modifying method 200 such that the entire set of finite addresses received at block 205 is contacted. This can be effected by setting “a” at block 210 to equal the total number of addresses received at block 205 . Alternatively, blocks 210 , 215 , 235 , 285 , 290 , etc. (i.e. those blocks that relate to counting) can be omitted. Furthermore, various ones of the validations (e.g. block 265 ) can be omitted if the potential resulting errors are acceptable within the parameters of the survey design.
As another example, the process for randomly selected addresses of first-type communication terminals can be effected in different ways. For example, seeds can be downloaded from an external vendor (e.g. which operates database 104 ) which contain unique ten-digit phone numbers, as well as any other identifying fields in the seed sample.
The seeds can then be imported into a SQL Server database and stored in storage 66 . During the important, each seed is assigned its own numeric Increment value, which is initially set to zero and constrained within the range 0-9,999.
A sample size and all the filters to be applied to the seeds are then manually provided through terminal 78 .
Processing unit 58 then retrieves the entire set of seeds from database 66 matching the specified filters and enumerates them sequentially. If no seeds match the conditions, the process is terminated. Otherwise, the processing unit 58 calculates and displays the ratio of sample size to number of seeds.
Processing unit 58 then uses a random number generator operation. Any off-the-shelf random number generator operation can be used, but in one example, where the SQL database at storage 66 is a Microsoft® SQL server, then the random number generator operation provided with that SQL software can be used.
Processing unit 58 uses the random number generator to obtain a random floating-point value between zero and one. Processing unit 58 multiplies the value by the number of seeds and discards all the digits after decimal point. The resulting number is then used by the processing unit 58 to pick a seed with the same sequential number from the previously selected set. This process provides processing unit 58 with a randomly selected seed.
An increment counter associated with the seed is increased by one by processing unit 58 . If the increment counter result equals 10,000, then the increment value is reset to 0.
The processing unit 58 then adds the last four digits of the phone number contained in the selected seed and the increment value. If the resulting value contains more than four digits, only the four least significant digits are stored in storage 66 by processing unit 58 . If the result contains less than four digits, processing unit 58 appends zeroes to the left of the result in order to produce a four-digit value. This procedure allows for the same seed to be used 10,000 times before producing a duplicate value, which effectively helps achieve the functionality of block 240 .
The resulting four-digit value is then appended to the first six digit of the phone number contained in the selected seed. This results in a ten-digit phone number that becomes a candidate for use at block 225 .
If the newly generated phone number is already present in the current sample, then it is discarded by processing unit 58 . Otherwise, the number appended to the sample along with the area code, first character of the postal code or zip code of a physical address corresponding to the location of first-type terminal 86 , and first three characters of the postal code associated with the seed. Each generated number is saved as record in a comma-separated file (or other database format) containing these four columns.
Random number generation is then repeated until the sample reaches the size specified by user.
The foregoing is intended to provide non-limited examples of how the present invention can be implemented. The scope of time-limited monopoly sought is defined solely by the claims attached hereto.
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A computerized method and system for compiling electronic identifiers is provided. In one embodiment a computer-based engine is provided that includes a processor and two communication gateways. The first communication gateway connects to a plurality of first-type communication devices. The second communication gateway connects to a plurality of second-type communication devices. The processor is configured to randomly connect to at least one of the first-type communication devices and receive input representing an address of at least one of the second-type communication devices.
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TECHNICAL FIELD OF THE INVENTION
In drilling or completing oil or gas wells various strings of pipe are made up or disconnected in a vertical position in the derrick one joint at a time and are stored horizontally on pipe racks adjacent the rig. The floor of the rig is elevated substantially above the pipe rack and therefore transferring a pipe between the pipe racks and the elevated rig floor requires careful handling both to protect the pipe and the personnel around the rig. Numerous solutions to the problem of transferring pipe from rack to rig have been suggested: for example, U.S. Pat. Nos. 4,083,193; 4,054,210; and 4,235,566.
Heavy joints of casing or drill collars are more difficult to handle than smaller and lighter pipe such as drill pipe and therefore require more stable and more sophisticated pipe handling equipment including means for controlling the rate of acceleration and deceleration involved in moving massive objects to protect the pipe as well as the pipe handling apparatus.
SUMMARY OF THE INVENTION
An apparatus for transferring pipe between the pipe rack and the rig floor and particularly large diameter heavy casing, drill collars as well as drill pipe, includes a horizontal base structure to be positioned on the ground between the pipe racks so as to receive pipe from either side. Nested within the base is a trough trestle, the front end of which is attached to cariages slidably mounted on an inclined track which guides the front end of the trestle as it is raised from the base to a position adjacent the rig floor. The rear end of the trestle remote from the drilling rig has an articulated support leg, the upper end of which is pivotally connected to the trestle and the lower end of which is slidably mounted in the track in the base so that as the front end of the trestle is moved upwardly along the inclined track the rear articulated leg first slides forward in the track to a stop and then pivots and swings the rear of the trestle upwardly to a desired elevation. A telescopically mounted pipe receiving trough is mounted in the trough trestle which is moved outwardly to project the pipe over the rig floor at a height convenient for the reach of the rig crew who connect the upper end of the pipe to the rig elevators or other lifting apparatus in the derrick.
Reversal of the above procedure will enable a joint of pipe to be lowered from a suspended position in the derrick to the pipe rack or storage. The present invention includes means for tilting the trough to either side for discharging pipe to the racks on either side as desired. The present invention also includes means for controlling acceleration and deceleration of the trough and trough trestle and lifting and lowering operations to avoid shock loads imposed by sudden stopping with massive loads imposed on the structure.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial side elevation of an elevated rig floor with the pipe handling apparatus shown partially in elevation and partially in section in the nested position for receiving pipe from the adjacent pipe rack;
FIG. 2 is a sectional view taken on line 2--2 of FIG. 1 showing details of the trough mounted in the trough trestle in a position for receiving a joint of pipe;
FIG. 3 is a section view similar to that shown in FIG. 2 but showing the trough in an elevated and tilted position for discharging pipe from the trough;
FIG. 4 is a view partially in elevation and partially in section showing the trough trestle in an intermediate position between the nested position shown in FIG. 1 and the fully raised position shown in FIG. 5;
FIG. 5 is a view partially in elevation and partially in section showing the pipe handling apparatus in the elevated position with the trough carrying the pipe extended to position the end of the pipe above the edge of the rig floor;
FIG. 6 is a schematic view showing the lift cylinder and carriage arrangement for lifting the forward end of the trough trestle along the inclined track;
FIG. 7 is a sectional view taken on line 7--7 of FIG. 6 showing additional details of the carriage apparatus from the forward end of the trough trestle along the inclined track; and
FIGS. 8A, B and C and 9A, B and C are schematic views illustrating the track for lifting the rear end of the trough trestle.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Illustrated in FIGS. 1 and 2 of the drawings is the base support B which comprises a plurality of longitudinally extending structural members 12 and 13 which are secured together by vertical supports 14 and horizontal members 15 to form an open top U-shaped truss which is adapted to be positioned on the ground adjacent a drilling rig R between the pipe rack (not shown) in the position usually occupied by the catwalk. Nested within the open-top U-shaped base member B is the trough trestle T in which the trough T' is telescopically mounted. The trough trestle T is supported at its front end by the carriage C which runs on the spaced inclined tracks K which extend from the front end of the base B upwardly to a point adjacent the edge of the elevated rig floor F. As shown, the rig R includes substructure S as well as rig floor F with the rig floor being supported at an elevation of twenty to forty feet above the ground on the substructure S depending upon the particular drilling rig configuration. If desired, the track K can be inclined at the same angle adjacent to the normal V door ramp and secured to the rig substructure or other suitable support means.
The carriage C comprises a U-shaped channel body including rollers 20 received in facing U-shaped channel tracks 22 which are secured in spaced relation by suitable transverse members or a plate 22', as desired.
The carriage has ears 24 which receive pin 25 for pivotally mounting the trough trestle T to the carriage. Such carriage C is connected to a pair of chains 27 which are rove over a pair of spaced sheaves 28 mounted on the end of the hydraulic lift piston 29 positioned within the U-shaped channel 30 on which the rollers 20 are mounted. One end of the chain 27 is secured to the lift piston cylinder 32 which is mounted on the forward end of the base B or to some point on the inclined track K, as desired. The other end of the chain 27 is secured to the carriage C by a suitable pin or other securing means 33.
The piston in the lift cylinder 32 travels approximately half of the distance travelled by the carriage C due to the chain drive arrangement shown in FIG. 6.
The rear end of the trough trestle T is carried on the articulated leg L which comprises a triangular truss type member having a forward or upper leg 44 and a shorter or lower leg 45 with the ends of such legs connected together by a pin which carries a roller 46 that moves in the track 48. A short leg 49 connects the ends of the legs 45 and 44 to form the articulated leg L. The track 48 includes a stop 48' at the forward end which limits forward movement of the roller 46 on the forward end of the articulated leg L. When the front end of the trough truss T is raised along the inclined track K into the successive positions shown in FIGS. 4 and 5 the rear end of the trough trestle T is first moved forward until the roller 46 engages the stop 48' and thence the continued upward and forward movement of the carriage C along the inclined track K causes the rear end of the trough trestle to move upwardly and forwardly on the articulated leg L. With this arrangement no independent vertical assist is required to assist in the initial lifting of the rear end of the trough trestle T'.
After reaching the uppermost position shown in FIG. 5, the trough T' is moved telescopically relative to the trough trestle T by means of a double acting hydraulic cylinder 60 as shown in FIGS. 4 and 5. In FIG. 4 the trough T' is in a retracted position relative to the trestle T and in FIG. 5 the trough T' is shown in a telescopically extended position relative to the trough trestle T. A single piston rod 61 extends through the cylinder 60 and is provided with a piston (not shown) which may be shifted hydraulically from end to end of the cylinder 60. Chain sheaves 62 and 64 are secured to the upper and lower ends, respectively, of the rod 61 for receiving drive chain 62' and 64' connected to the trough upper and lower trolleys, 65 and 66 on the trough T'.
One end of the chain 62' is connected to the trough T' at 70 and the other end of such chain is connected to the cylinder 60 or supporting structure; similarly, one end of the chain 64' is connected to the trough at 71 and the other end is connected to the cylinder 60 or supporting structure.
With the chain 62' and 64' rove over their respective sheaves 62 and 64 mounted on the common piston rod 61, it will be appreciated that the double acting cylinder 60 provides positive hydraulic control means for both extending and retracting the trough T' with respect to the trough trestle T to thereby provide a positive control for accelerating and decelerating motion of the loaded trough T'. As the rod 61 is shifted upwardly from the position shown in FIG. 4 to the position shown in FIG. 5 the chain moves the trough T' from its retracted position to the extended position for placing the end of the pipe P over the edge of the rig floor F. Of course, it will be appreciated that the trough T' is not shifted to its telescopically extended position until after the trough trestle T has been raised to a sufficient elevation to enable the end of the trough T' to clear the upper edge of the rig floor F. Similarly, in lowering the loaded trough T' the piston in the cylinder 60 is moved from the extended position shown in FIG. 5 to the retracted position shown in FIG. 4 thereby shifting the sheave 64 rearwardly of the trough trestle T to thereby move the trough T' into its retracted position shown in FIG. 4. The piston rod 61 has a piston (not shown) that travels in either direction in the cylinder 60 to provide a means of positive control in both directions of travel to provide positive means to control the forces involved in accelerating and decelerating large masses, such as large diameter casing, drill collars and the like.
As shown in FIG. 2 of the drawings, the trough trestle T comprises a pair of flanged beam members 80 and 81 which are secured together at longitudinally spaced points by transverse web members 83. Secured in the inner facing sides of the beams 80 and 81 are a pair of inwardly facing U-shaped channel track members 85 and 86 which are provided for receiving rollers 87 and 88, respectively. Such rollers are secured by pins to parallel side members 90 and 91 which are connected by a transverse web member (not shown) to form the sides of the trough member T'. At the upper edges of the sides 90 and 91 are hinge members 90a and 91a, respectively having suitable openings therein for receiving pivot pins 95 (FIG. 3) for pivotally mounting a center section of the trough 96. It would be appreciated that there are a pair of longitudinally spaced hinge members 90a and 91a for receiving the pivot pins 95 in a number of places spaced along either edge of the trough 96. With this arrangement the trough member 96 may be tilted toward the side on which the pivot pins 95 are placed to enable the trough to discharge pipe to pipe racks on either side. Dual cylinder scissors jacks 101 and 102 are pivotally mounted on support arms 103 and 104 that are secured to the inner sides of the flanged beams 80 and 81, respectively. Such cylinders are pivoted on pivot pins 101a and 102a, respectively, which are carried by the support arms 103 and 104.
The scissors arrangement comprises four arms 105, 106, 107 and 108, respectively which are pinned together at their respective ends by means of pins 105a, 106a, 107a and 108a, respectively.
As shown in FIG. 2, the cylinders 101 and 102 are pivotally mounted on the transverse plates to permit free pivotal movement of the cylinder pistons 101b and 102b, respectively, upwardly against the pins 106a and 108a, respectively. Also shown in FIG. 1 the upper ends of the cylinder rods 101b and 102b, respectively are radiused for receiving pins 106a and 108a. As shown in FIG. 2, in the retracted position the radiused ends disengage the pins. With the trough 96 pinned to the hinge members 90a, when the piston rods 101b and 102b are extended upwardly and move the pins 108a and 106a upwardly, the trough 96 which is pivoted at 107a and 90a is tilted to the lefthand side as viewed in FIG. 3 of the drawings. It will be appreciated that by pinning the right hand edge of the trough 96, it will be tilted to the right as viewed in FIG. 3 when the scissors arrangement is in the elevated position as illustrated in FIG. 3. Thus, by pinning either one side or the other of the trough 96, it may be tilted either right or left for receiving or discharging pipe from pipe racks placed on either side of the trough.
Shown in FIG. 8 of the drawings is an alternative embodiment of the track for guiding the articulated leg in raising the rear end of the trough trestle T. In the FIG. 8 embodiment there are two rear tracks; a substantially horizontal track 101 and upwardly curved track 102. The track 101 receives the lower end 103 of the articulated leg L' and the track 102 receives a roller 104 which is positioned at the rear end of the articulated leg. As shown in phantom in the drawing, movement of the front end of the trough trestle upwardly along the inclined track K causes the articulated leg to move forward along the tracks 101 and 102, the track 102 causing the leg to begin pivoting upwardly in the curved portion 102a and thereafter when the roller 103 strikes the stop 105 in the track 101, the articulated leg L' is pivoted upwardly into a position for raising the rear end of the trough trestle T.
In FIG. 9 of the drawings is illustrated yet another embodiment of the means for guiding the movement of the articulated leg L" and it is moved by movement of the forward end of the trough trestle T' upwardly along the inclined tracks K. In this embodiment the rear track 109 is inclined upwardly and then turned into a horizontal plane so that as the trough trestle T' begins its upward movement along the track K, the rear roller 110 will start up the inclined track and as it reaches the flat or substantially horizontal portion of the track 110, the rear of the trough trestle will move horizontally forward until such time that the lower end of the articulated leg reaches the stop in the lower track which will cause it to begin pivotal motion which will then cause the rear end of the trestle to again assume an upward and forward direction of movement.
Sliding the rear articulated leg forward as the carriage C is lifting the front end of the trough trestle T acts to increase the angle between the track trestle and the base prior to initiating an upward lifting moment on the rear end of the trough trestle, thus significantly reducing the force required to lift the rear end of the trough trestle T on the articulated leg L. This eliminates the need for an independent lifting apparatus which would otherwise be required with articulated lifting devices. It has been found that in the preferred embodiment, the trough trestle T should attain an angle of at least twenty-two degrees with respect to the longitudinal axis of the horizontal support base before the rear end of the trough trestle T' begins to swing vertically upwardly.
In operation of the apparatus of the present invention the trough trestle T begins in a retracted or nested position in the base support as illustrated in FIG. 1 of the drawings. The lift cylinder 32 is actuated causing the sheave 28 to move upwardly to the position shown in the FIG. 5 of the drawings thereby moving the carriage C upwardly to a position adjacent the rig floor F and moving the trough trestle T upwardly to the inclined position shown in FIG. 5 also. With the upward movement of the trough trestle T, the rear articulated leg L is caused to move forward in the track 48 until the forward end 46 of the leg L strikes the stop 48' and thereafter continued upward movement of the carriage along the inclined track K causes the articulated leg to be pivoted as shown in FIGS. 4 and 5 until it is in a substantially upright position and thereby lifts the rear end of the trough trestle to a sufficient height that the pipe P which projects out of the trough T' is positioned over the edge of the rig floor F at a height which the rig crew working on a rig floor can conveniently reach.
Once the trough trestle has been moved upwardly to the inclined position shown in FIG. 5, the dual acting piston in the cylinder 60 is actuated to move the sheave 62 upwardly to the position shown in FIG. 5 thereby shifting the trough T' to the extended position projecting out over the edge of the rig floor F. This movement positions the pipe P at a position to enable the crew on a rig floor to attach it to rig elevators (not shown) or other lifting apparatus to lift the pipe from the trough T' into a substantially vertical position in the rig where it can thereafter be lowered into position for connecting to a string of pipe supported in the rig.
In laying down pipe with the apparatus of the present invention it is first suspended in the rig and then swung over to place the lower end of the pipe in the extended trough T' and thereafter lowering of the lifting apparatus in the rig will lower the pipe as it is slid into the through until it strikes the hydraulic bumper 99 which is positioned at the rear end of the trough T'. With the pipe thus positioned in the trough T', the dual acting piston in the cylinder 60 is actuated to cause the sheave 64 to be moved downwardly into the position shown in FIG. 4 to thereby retract the trough in the trough trestle. Thereafter, downward movement of the carriage C is caused by lowering the piston in the cylinder 32 to turn the through trestle to the position shown in FIG. 1. With the trough in this position, the cylinders 101 and 102 are actuated to lift the scissors jack so as to lift the portion of the trough T' which is pivotally mounted as shown in FIG. 2 to a position such as shown in FIG. 3 to thereby tilt to one side and cause the pipe carried in the trough to be rolled out of the trough and onto an adjacent pipe rack.
The foregoing disclosure and description of the invention are illustrative and explanatory thereof and various changes in the size, shape and materials as well as in the details of the preferred embodiment may be made without departing from the spirit of the invention.
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A pipe pick-up and laydown machine for lifting a joint of pipe from a generally horizontal position on a pipe rack to an inclined and elevated position relative to an elevated rig floor for connection to rig elevators by the drilling crew. The apparatus includes a horizontal base position adjacent the pipe racks with a pipe carrying trough slidably mounted in a trough trestle which can telescope in and out of one end of the trestle. An inclined track extends from one end of the base to a position near the edge of the rig floor and structure is provided for lifting the front end of the trough trestle along the inclined track. The rear end of the trough trestle is mounted on a sliding articulating arm which first moves forward as the front end of the trough trestle is elevated on the inclined track and then stops and pivots to raise the rear end of the trestle to incline the pipe carrying trough at a desired elevation when extended over one edge of the rig floor. The operation is reversed when laying down pipe. The apparatus also can roll pipe to pipe racks positioned on either side of the apparatus.
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INCORPORATION BY REFERENCE
[0001] This application is a continuation of and claims priority to U.S. patent application Ser. No. 15/072,174, filed Mar. 16, 2016, which claims the benefit of U.S. Provisional Patent Application No. 62/202,104, filed Aug. 6, 2015, both of which are incorporated by reference in their entireties. The disclosure below also references various features of U.S. patent application Ser. No. 14/579,752, filed Dec. 22, 2014, and U.S. Pat. No. 8,788,405 B1, issued Jul. 22, 2014. The entire disclosures of those applications are hereby made part of this specification as if set forth fully herein and incorporated by reference for all purposes, for all that they contain.
BACKGROUND
[0002] Embodiments of the present disclosure generally relate to identifying phishing, spam, and malicious electronic communications.
[0003] Phishing communications are unsolicited electronic communications, from fraudulent senders masquerading as trustworthy entities, seeking sensitive information from recipients of the unsolicited electronic communications. Spam communications are unsolicited bulk communications akin to electronic junk mail. Malicious communications include unsolicited communications sent with the intention of disrupting the recipient's computer or network communications intended to install “malware” (hostile or intrusive software, in the form of executable code, scripts, active content, and other software, which includes computer viruses, worms, Trojan horses, ransomware, spyware, adware, scareware, and other malicious programs). It is important for local network administrators to identify such communications and take appropriate actions to protect the local network or the recipients' computers or sensitive information. In this disclosure, the term “undesirable electronic communications” or “undesirable communications” encompasses, among other things, phishing, spam, and other malicious electronic communications, including those discussed above and others described herein.
SUMMARY
[0004] A recipient of a potentially undesirable electronic communication can forward the electronic communication to an administrator. A computer-implemented data analysis system can group the potentially undesirable electronic communication with any other similar potentially undesirable electronic communications in a data cluster and classify the data cluster with a classification reflecting a priority for assessing the potentially undesirable electronic communication(s) in the data cluster. The system can also generate user interface data for rendering an interactive user interface allowing an analyst to view the context and scope of the data cluster and triage all potentially undesirable electronic communication(s) in the data cluster as a group. The systems, methods, and devices described herein each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure, several non-limiting features will now be discussed briefly.
[0005] Embodiments of the present disclosure relate to a data analysis system that may automatically generate memory-efficient clustered data structures, automatically analyze those clustered data structures, automatically tag and group those clustered data structures in tiers, and provide results of the automated analysis and grouping in an optimized way to an analyst. The automated analysis of the clustered data structures (also referred to herein as “data clusters” or simply “clusters”) may include an automated application of various criteria or rules so as to generate a tiled display of the tiers of related data clusters such that the analyst may quickly and efficiently evaluate the tiers of data clusters. In particular, the tiers of data clusters may be dynamically re-grouped and/or filtered in an interactive user interface so as to enable an analyst to quickly navigate among information associated with various tiers and efficiently evaluate the tiers of data clusters.
[0006] As described below, tiers of data clusters may include one or more potentially undesirable electronic communications, such as emails, text messages, newsgroup postings, and the like. In an example application, a human analyst may be tasked with deciding whether potentially undesirable electronic communication represents a phishing, spam, or malicious communication. In a very large local network, such as in a company employing hundreds of thousands of employees, such decisions may require a large team of analysts evaluating massive numbers of individual electronic communications. Certain embodiments include the inventive realization that grouping related potentially undesirable electronic communications in a data cluster can reduce the labor required for such decision making by allowing for triage of all potentially undesirable electronic communication(s) in the data cluster as a group.
[0007] Moreover, an individual potentially undesirable electronic communication often includes insufficient information for the analyst to effectively make such decisions. For example, the analyst could initiate an investigation with a single potentially undesirable electronic communications, such as a potentially malicious email. If the analyst examined this email by itself, then the analyst may not observe any suspicious characteristics. Certain embodiments include the inventive realization that an analyst may make better decisions based on a collection of related potentially undesirable electronic communications. For instance, two malicious emails may be related by an identical sender or similar subject fields. By viewing the emails in the context of a data cluster, the analyst could discover additional potentially undesirable electronic communications relating to the original email because of a shared characteristic. The analyst could then mark all the potentially undesirable electronic communications in the data cluster as malicious, based on the shared characteristic.
[0008] As described herein, various embodiments of the data analysis system of the present disclosure automatically create clusters of related potentially undesirable electronic communications, tags and groups the clusters in tiers, and generates an interactive user interface in which, in response to inputs from the analyst, information related to the tiers of clusters may be efficiently provided to the analyst. Accordingly, the analyst may be enabled to efficiently evaluate the tiers of clusters.
[0009] Generation of the memory-efficient clustered data structures may be accomplished by selection of one or more initial potentially undesirable electronic communication of interest (also referred to herein as “seeds”), adding of the initial potentially undesirable electronic communication to the memory-efficient clustered data structure (or, alternatively, designating the initial potentially undesirable electronic communication as the clustered data structure, or an initial iteration of the clustered data structure), and determining and adding one or more related potentially undesirable electronic communications to the cluster. The number of potentially undesirable electronic communications in the cluster may be several orders of magnitude smaller than in the entire electronic collection of data described above because only potentially undesirable electronic communication related to each other are included in the clusters.
[0010] Additionally, the automated analysis and scoring of clusters (as mentioned above) may enable highly efficient evaluation of the various data clusters by a human analyst. For example, the interactive user interface is generated so as to enable an analyst to quickly view critical groups of data clusters (as determined by automated grouping in tiers), and then in response to analyst inputs, view and interact with the generated information associated with the clusters. In response to user inputs the user interface may be updated to display data associated with each of the generated groups of clusters if the analyst desires to dive deeper into data associated with a given group of clusters.
[0011] In various embodiments, seeds may be automatically selected/generated according to various seed determination strategies, and clusters of related potentially undesirable electronic communications may be generated based on those seeds and according to cluster generation strategies (also referred to herein as “cluster strategies”). Also, as mentioned above, the system may rank or prioritize the generated clusters. High priority clusters may be of greater interest to an analyst as they may contain related potentially undesirable electronic communications that meet particular criteria related to the analyst's investigation. In an embodiment, the system may enable an analyst to advantageously start an investigation with a prioritized cluster, or group of clusters, including many related potentially undesirable electronic communications rather than a single randomly selected potentially undesirable electronic communications. Further, as described above, the cluster prioritization may enable the processing requirements of the analyst's investigation to be highly efficient as compared to processing of the huge collection of data described above. As mentioned above, this is because, for example, a given investigation by an analyst may only require storage in memory of a limited number of potentially undesirable electronic communications associated with a small number of clusters, and further, a number of potentially undesirable electronic communications in a cluster may be several orders of magnitude smaller than in the entire electronic collection of data described above because only potentially undesirable electronic communications related to each other are included in the cluster. Further, an analyst may not need to view many (or, alternatively, any) potentially undesirable electronic communications associated with a cluster to evaluate the cluster, but rather may evaluate the cluster based on the automatically generated cluster information.
[0012] In various embodiments, grouping of related data clusters enables an analyst to review the data in a logical way. For example, the data clusters may be tagged and grouped according to a recipient's position in the local network. Further, when a group of related data clusters is determined by the analyst to not be important, the analyst may quickly dismiss all potentially undesirable electronic communications of that group of clusters, rather than each potentially undesirable electronic communication separately. This advantageously enables computationally-efficient processing, allowing analysts to process entire clusters with one click rather than email by email.
[0013] According to an embodiment, a computer system is disclosed, the system comprising one, some, or all of the following features, as well as features described elsewhere in this disclosure. The system can comprise one or more computer readable storage devices configured to store one or more software modules including computer executable instructions, records of first electronic communications to internal recipients within a local network for a period of time, the records reflecting, for each of the first electronic communications, a plurality of characteristics, and/or a plurality of prescreened electronic communications, at least some of the prescreened electronic communications in the first electronic communications, each prescreened electronic communication preliminarily identified as a potential undesirable electronic communication, and each prescreened electronic communication comprising the plurality of characteristics.
[0014] The system can also comprise one or more hardware computer processors in communication with the one or more computer readable storage devices and configured to execute the one or more software modules in order to cause the computer system to: access, from the one or more computer readable storage devices, the plurality of prescreened electronic communications and the records; group, from the plurality of prescreened electronic communications, a data cluster of the prescreened electronic communications sharing a similar characteristic from the plurality of characteristics; based on a first characteristic associated with the data cluster and the same first characteristics of the records, identify recipients associated with the data cluster from the first electronic communications; based on one or more attributes of the data cluster, classify the data cluster with a classification reflecting a priority for assessing whether the prescreened electronic communications associated with the data cluster are undesirable electronic communications, such that, once initiated, the classifying is performed by the one or more hardware computer processors, without the need for manually performing the classifying; generate user interface data for rendering an interactive user interface on a computing device, the interactive user interface including an element selectable by a user, the selectable element reflecting the classification; and/or update the user interface data such that, after the selectable element is selected by the user, the interactive user interface further includes informational data regarding the data cluster, the informational data reflecting the recipients associated with the data cluster.
[0015] According to an aspect, the plurality of characteristics can comprise a from field corresponding to a purported author of the respective first electronic communication, one or more recipient fields corresponding to the recipients of the respective first electronic communication, and a subject field corresponding to a purported topic of the respective first electronic communication.
[0016] According to another aspect, the one or more attributes can comprise the number of prescreened electronic communications in the data cluster. The one or more attributes can comprise an identity of one or more recipients of the prescreened electronic communications in the data cluster. Each prescreened electronic communication can further comprise a message body, and the one or more hardware computer processors in communication with the one or more computer readable storage devices can be configured to execute the one or more software modules in order to cause the computer system to parse the message body for any uniform resource locators. The one or more attributes can comprise a determination that the message body includes at least one uniform resource locator.
[0017] According to yet another aspect, the computer system can further comprise a network connection configured to access, from one or more remote networks not within the local network, one or more domain name system blackhole lists or real-time blackhole lists, the one or more attributes comprising a determination that the message body includes at least one uniform resource locator, or a portion thereof, on the domain name system blackhole list(s) or real-time blackhole list(s). The one or more computer readable storage devices can be further configured to store a log of requests from the local network seeking resources outside the local network, and the one or more hardware computer processors in communication with the one or more computer readable storage devices can be configured to execute the one or more software modules in order to cause the computer system to identify instances in the log indicating a request from the local network seeking a parsed uniform resource locator. The informational data can further reflect an identification of the instances in the log.
[0018] According to another aspect, the one or more hardware computer processors in communication with the one or more computer readable storage devices can be configured to execute the one or more software modules in order to further cause the computer system to receive a disposition from the user that the prescreened electronic communications associated with the data cluster are undesirable electronic communications. The one or more hardware computer processors in communication with the one or more computer readable storage devices can be configured to execute the one or more software modules in order to further cause the computer system to, based on the disposition, transmit an electronic notification to the recipients associated with the data cluster.
[0019] According to an embodiment, a computer-implemented method is disclosed, the method comprising one, some, or all of the following features, as well as features described elsewhere in this disclosure. The method can comprise, as implemented by one or more computer readable storage devices configured to store one or more software modules including computer executable instructions, and by one or more hardware computer processors in communication with the one or more computer readable storage devices configured to execute the one or more software modules, accessing, from the one or more computer readable storage devices, a plurality of electronic communications, each comprising a message body, a from field corresponding to a purported author of the respective prescreened electronic communication, and a subject field corresponding to a purported topic of the respective prescreened electronic communication, grouping, from the plurality of electronic communications, a data cluster of the electronic communications sharing a similar from field or a similar subject field, and/or accessing, from one or more remote networks, one or more domain name system blackhole lists or real-time blackhole lists.
[0020] The method can further comprise, for one or more of the electronic communications in the data cluster, parsing the respective message body for uniform resource locators, based at least in part on a determination that the message body includes at least one uniform resource locator, or a portion thereof, on the domain name system blackhole list(s) or real-time blackhole list(s), classifying the data cluster with a classification reflecting a priority for assessing whether the electronic communications associated with the data cluster are undesirable electronic communications, such that, once initiated, the classifying is performed by the one or more hardware computer processors, without the need for manually performing the classifying, generating user interface data for rendering an interactive user interface on a computing device, the interactive user interface including an element selectable by a user, the selectable element reflecting the classification, and/or updating the user interface data such that, after the selectable element is selected by the user, the interactive user interface further includes informational data regarding the data cluster.
[0021] According to an aspect, each electronic communication can further comprise the one or more recipient fields. The computer-implemented method can further comprise accessing records of first electronic communications to internal recipients within a local network for a period of time, the records reflecting, for each of the first electronic communications, a from field corresponding to a purported author of the respective first electronic communication, one or more recipient fields corresponding to the recipients of the respective first electronic communication, and a subject field corresponding to a purported topic of the respective first electronic communication.
[0022] According to another aspect, the computer-implemented method can further comprise, based on the from field or the subject field associated with the data cluster and the from fields or the subject fields of the records, identifying additional recipients associated with the data cluster from the first electronic communications. The classifying can be further based, at least in part, on an identity of one or more the recipients of the electronic communications in the data cluster.
[0023] According to yet another aspect, the method can further comprise accessing a log of requests from the local network seeking resources outside the local network; and identifying instances in the log indicating a request from the local network seeking a parsed uniform resource locator. The informational data can comprise an identification of the instances in the log.
[0024] According to another aspect, the method can further comprise receiving a disposition from the user that the electronic communications associated with the data cluster are undesirable electronic communications. The method can further comprise, based on the disposition, transmitting an electronic notification to recipients associated with the data cluster and the additional recipients.
[0025] In various embodiments, computer-implemented methods are disclosed in which, under control of one or more hardware computing devices configured with specific computer executable instructions, one or more aspects of the above-described embodiments are implemented and/or performed.
[0026] In various embodiments, a non-transitory computer-readable storage medium storing software instructions is disclosed that, in response to execution by a computer system having one or more hardware processors, configure the computer system to perform operations comprising one or more aspects of the above-described embodiments.
[0027] Further, as described herein, a data analysis system may be configured and/or designed to generate user interface data useable for rendering the various interactive user interfaces described. The user interface data may be used by the system, and/or another computer system, device, and/or software program (for example, a browser program), to render the interactive user interfaces. The interactive user interfaces may be displayed on, for example, electronic displays (including, for example, touch-enabled displays).
[0028] Additionally, it has been noted that design of computer user interfaces “that are useable and easily learned by humans is a non-trivial problem for software developers.” (Dillon, A. (2003) User Interface Design. MacMillan Encyclopedia of Cognitive Science, Vol. 4, London: MacMillan, 453-458.) The various embodiments of interactive and dynamic user interfaces of the present disclosure are the result of significant research, development, improvement, iteration, and testing. This non-trivial development has resulted in the user interfaces described herein which may provide significant cognitive and ergonomic efficiencies and advantages over previous systems. The interactive and dynamic user interfaces include improved human-computer interactions that may provide reduced mental workloads, improved decision-making, reduced work stress, and/or the like, for an analyst user.
[0029] Further, the interactive and dynamic user interfaces described herein are enabled by innovations in efficient interactions between the user interfaces and underlying systems and components. For example, disclosed herein are improved methods of receiving user inputs, translation and delivery of those inputs to various system components (for example, retrieval of clusters), automatic and dynamic execution of complex processes in response to the input delivery (for example, grouping and filtering of clusters), automatic interaction among various components and processes of the system, and/or automatic and dynamic updating of the user interfaces. The interactions and presentation of data via the interactive user interfaces described herein may accordingly provide cognitive and ergonomic efficiencies and advantages over previous systems.
[0030] Advantageously, according to various embodiments, the disclosed techniques provide a more effective starting point and user interface for an investigation of potentially undesirable electronic communications of various types. An analyst may be able to start an investigation from a group of clusters of related potentially undesirable electronic communications instead of an individual potentially undesirable electronic communication, which may reduce the amount of time and effort required to perform the investigation. The disclosed techniques may also, according to various embodiments, provide a prioritization of multiple clusters, and dynamic re-grouping of related clusters and cluster filtering. For example, the analyst may also be able to start the investigation from a high priority group of clusters, which may allow the analyst to focus on the most important investigations, and may quickly evaluate that group of clusters based on the efficient user interface generated by the system. In each case, the processing and computational requirements of such an investigation may be significantly reduced due to the creation and use of highly efficient cluster data structures of related potentially undesirable electronic communications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The following drawings and the associated descriptions are provided to illustrate embodiments of the present disclosure and do not limit the scope of the claims. Aspects and many of the attendant advantages of this disclosure will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
[0032] FIG. 1 is a block diagram of a server system, as used in an embodiment.
[0033] FIG. 2 is a block diagram of a computing system for analyzing potentially undesirable electronic communications, as used in an embodiment.
[0034] FIG. 3 is a process of analyzing potentially undesirable electronic communications, as used in an embodiment.
[0035] FIG. 4 is process of taking action based on potentially undesirable electronic communications, as used in an embodiment.
[0036] FIG. 5 is a process of analyzing potentially undesirable electronic communications and taking action based thereon, as used in an embodiment.
[0037] FIG. 6 is a process of analyzing potentially undesirable electronic communications, as used in an embodiment.
[0038] FIG. 7 is a data cluster analysis user interface in which multiple data clusters are prioritized, as used in an embodiment.
[0039] FIG. 8 is a data cluster analysis user interface showing potentially undesirable electronic communications for a high priority group of data clusters, as used in an embodiment.
[0040] FIGS. 9-13 are dossier analysis user interfaces showing informational data regarding a data cluster, as used in an embodiment.
[0041] FIGS. 14A and 14B are dossier analysis user interfaces showing informational data regarding a data cluster, as used in an embodiment.
[0042] In the drawings, the first one or two digits of each reference number typically indicate the figure in which the element first appears. Throughout the drawings, reference numbers may be reused to indicate correspondence between referenced elements. Nevertheless, use of different numbers does not necessarily indicate a lack of correspondence between elements. And, conversely, reuse of a number does not necessarily indicate that the elements are the same.
DETAILED DESCRIPTION
[0043] Although certain preferred embodiments and examples are disclosed below, inventive subject matter extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and to modifications and equivalents thereof. Thus, the scope of the claims appended hereto is not limited by any of the particular embodiments described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding certain embodiments; however, the order of description should not be construed to imply that these operations are order dependent. Additionally, the structures, systems, and/or devices described herein may be embodied as integrated components or as separate components. For purposes of comparing various embodiments, certain aspects and advantages of these embodiments are described. Not necessarily all such aspects or advantages are achieved by any particular embodiment. Thus, for example, various embodiments may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may also be taught or suggested herein.
[0044] Terms
[0045] In order to facilitate an understanding of the systems and methods discussed herein, a number of terms are defined below. The terms defined below, as well as other terms used herein, should be construed broadly to include, without limitation, the provided definitions, the ordinary and customary meanings of the terms, and/or any other implied meanings for the respective terms. Thus, the definitions below do not limit the meaning of these terms, but only provide example definitions.
[0046] Database: A broad term for any data structure for storing and/or organizing data, including, but not limited to, relational databases (for example, Oracle database, mySQL database, and the like), spreadsheets, XML files, and text files, among others. The various terms “database,” “data store,” and “data source” may be used interchangeably in the present disclosure.
[0047] Potentially undesirable electronic communication: An electronic communication that has been preliminarily screened and identified as a possible undesirable electronic communication but that has not been triaged by a designated analyst and conclusively identified as an undesirable electronic communication. A potentially undesirable electronic communication may represent a document or other unstructured data source such as an e-mail message, a news report, or a written paper or article. Each potentially undesirable electronic communication may be associated with a unique identifier that uniquely identifies it. The preliminary screening can be done by a human recipient. The preliminary screening can be done automatically, without human intervention, by electronic rules or a program.
[0048] Cluster: A group or set of one or more related potentially undesirable electronic communications. A cluster may be generated, determined, and/or selected from one or more sets of potentially undesirable electronic communication according to a cluster generation strategy. A cluster may further be generated, determined, and/or selected based on a seed. For example, a seed may comprise an initial potentially undesirable electronic communication of a cluster. Potentially undesirable electronic communications related to the seed may be determined and added to the cluster. Further, additional potentially undesirable electronic communications related to any clustered potentially undesirable electronic communication may also be added to the cluster iteratively as indicated by a cluster generation strategy. Potentially undesirable electronic communications may be related by any common and/or similar properties, metadata, types, relationships, and/or the like. Clusters may also be referred to herein as “data clusters.”
[0049] Seed: One or more potentially undesirable electronic communications that may be used as a basis, or starting point, for generating a cluster. A seed may be generated, determined, and/or selected from one or more sets of potentially undesirable electronic communications according to a seed generation strategy. For example, seeds may be generated from potentially undesirable electronic communications accessed from various databases and data sources.
[0050] Dossier: A collection of information associated with a cluster or a group of clusters and/or a user interface for displaying such a collection.
[0051] Overview
[0052] When investigating phishing, spam, or malicious communications, an analyst may have to make decisions regarding a large number of electronic communications that may or may not be related to one another, and which may be stored in an electronic data store or memory. For example, such a collection of data may include hundreds of thousands or millions of potentially undesirable electronic communications, and may consume significant storage and/or memory. Determination and selection of relevant communications within such a collection may be extremely difficult for the analyst. Further, processing of such a large collection of data (for example, as an analyst uses a computer to sift and/or search through large pluralities of potentially undesirable electronic communications) may be extremely inefficient and consume significant processing and/or memory resources.
[0053] This disclosure relates to a system for analyzing potentially undesirable electronic communications (also referred to herein as the “system”) in which computationally-efficient clustered data structures (also referred to herein as “clusters”) of related electronic communications may be automatically generated and analyzed, tagged, grouped, and results may be provided for interaction from an analyst, for example. Generation of clusters may begin by automatic generation, determination, and/or selection of one or more initial communications of interest, called “seeds.” Clusters of related electronic communications may be generated based on those seeds and according to cluster generation strategies (also referred to herein as “cluster strategies,” “clustering strategies,” and/or “cluster generation rules”). Seeds and related electronic communications may be accessed from various databases and data sources including, for example, databases maintained by financial institutions, government entities, private entities, public entities, and/or publicly available data sources. Such databases and data sources may include a variety of information and data, such as, for example, computer network-related data, and/or computer-related activity data, among others. Further, the databases and data sources may include various relationships that link and/or associate electronic communications with one another. Various electronic communications and relationships may be stored across different systems controlled by different items and/or institutions. According to various embodiments, the system may bring together data from multiple data sources in order to build clusters.
[0054] In the following description, numerous specific details are set forth to provide a more thorough understanding of various embodiments of the present disclosure. It will be apparent to one of skill in the art, however, that the systems and methods of the present disclosure may be practiced without one or more of these specific details.
DESCRIPTION OF THE FIGURES
[0055] Embodiments of the disclosure will now be described with reference to the accompanying Figures. The terminology used in the description is not intended to be interpreted in any limited or restrictive manner, simply because it is being utilized in conjunction with a detailed description of certain specific embodiments of the disclosure. Furthermore, embodiments of the disclosure described above and/or below may include several novel features, no single one of which is solely responsible for its desirable attributes or which is essential to practicing the embodiments of the disclosure herein described.
[0056] I. Implementation Mechanisms
[0057] According to one embodiment, the techniques described herein are implemented by one or more special-purpose computing devices. The special-purpose computing devices may be hard-wired to perform the techniques, or may include digital electronic devices such as one or more application-specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs) that are persistently programmed to perform the techniques, or may include one or more general purpose hardware processors programmed to perform the techniques pursuant to program instructions in firmware, memory, other storage, or a combination. Such special-purpose computing devices may also combine custom hard-wired logic, ASICs, or FPGAs with custom programming to accomplish the techniques. The special-purpose computing devices may be desktop computer systems, server computer systems, portable computer systems, handheld devices, networking devices or any other device or combination of devices that incorporate hard-wired and/or program logic to implement the techniques.
[0058] Computing device(s) are generally controlled and coordinated by operating system software, such as iOS, Android, Chrome OS, Windows XP, Windows Vista, Windows 7, Windows 8, Windows Server, Windows CE, Unix, Linux, SunOS, Solaris, iOS, Blackberry OS, VxWorks, or other compatible operating systems. In other embodiments, the computing device may be controlled by a proprietary operating system. Conventional operating systems control and schedule computer processes for execution, perform memory management, provide file system, networking, I/O services, and provide a user interface functionality, such as a graphical user interface (“GUI”), among other things.
[0059] FIG. 1 is a block diagram that illustrates a computer system 100 upon which an embodiment may be implemented. For example, any of the computing devices discussed herein may include some or all of the components and/or functionality of the computer system 100 .
[0060] Computer system 100 includes a bus 102 or other communication mechanism for communicating information, and a hardware processor, or multiple processors, 104 coupled with bus 102 for processing information. Hardware processor(s) 104 may be, for example, one or more general purpose microprocessors.
[0061] Computer system 100 also includes a main memory 106 , such as a random access memory (RAM), cache and/or other dynamic storage devices, coupled to bus 102 for storing information and instructions to be executed by processor 104 . Main memory 106 also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor 104 . Such instructions, when stored in storage media accessible to processor 104 , render computer system 100 into a special-purpose machine that is customized to perform the operations specified in the instructions.
[0062] Computer system 100 further includes a read only memory (ROM) 108 or other static storage device coupled to bus 102 for storing static information and instructions for processor 104 . A storage device 110 , such as a magnetic disk, optical disk, or USB thumb drive (Flash drive), etc., is provided and coupled to bus 102 for storing information and instructions.
[0063] Computer system 100 may be coupled via bus 102 to a display 112 , such as a cathode ray tube (CRT) or LCD display (or touch screen), for displaying information to a computer user. An input device 114 , including alphanumeric and other keys, is coupled to bus 102 for communicating information and command selections to processor 104 . Another type of user input device is cursor control 116 , such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor 104 and for controlling cursor movement on display 112 . This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allows the device to specify positions in a plane. In some embodiments, the same direction information and command selections as cursor control may be implemented via receiving touches on a touch screen without a cursor.
[0064] Computing system 100 may include a user interface module to implement a GUI that may be stored in a mass storage device as executable software codes that are executed by the computing device(s). This and other modules may include, by way of example, components, such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables.
[0065] In general, the word “module,” as used herein, refers to logic embodied in hardware or firmware, or to a collection of software instructions, possibly having entry and exit points, written in a programming language, such as, for example, Java, Lua, C or C++. A software module may be compiled and linked into an executable program, installed in a dynamic link library, or may be written in an interpreted programming language such as, for example, BASIC, Perl, or Python. It will be appreciated that software modules may be callable from other modules or from themselves, and/or may be invoked in response to detected events or interrupts. Software modules configured for execution on computing devices may be provided on a computer readable medium, such as a compact disc, digital video disc, flash drive, magnetic disc, or any other tangible medium, or as a digital download (and may be originally stored in a compressed or installable format that requires installation, decompression or decryption prior to execution). Such software code may be stored, partially or fully, on a memory device of the executing computing device, for execution by the computing device. Software instructions may be embedded in firmware, such as an EPROM. It will be further appreciated that hardware modules may be comprised of connected logic units, such as gates and flip-flops, and/or may be comprised of programmable units, such as programmable gate arrays or processors. The modules or computing device functionality described herein are preferably implemented as software modules, but may be represented in hardware or firmware. Generally, the modules described herein refer to logical modules that may be combined with other modules or divided into sub-modules despite their physical organization or storage
[0066] Computer system 100 may implement the techniques described herein using customized hard-wired logic, one or more ASICs or FPGAs, firmware and/or program logic which in combination with the computer system causes or programs computer system 100 to be a special-purpose machine. According to one embodiment, the techniques herein are performed by computer system 100 in response to processor(s) 104 executing one or more sequences of one or more instructions contained in main memory 106 . Such instructions may be read into main memory 106 from another storage medium, such as storage device 110 . Execution of the sequences of instructions contained in main memory 106 causes processor(s) 104 to perform the process steps described herein. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions.
[0067] The term “non-transitory media,” and similar terms, as used herein refers to any media that store data and/or instructions that cause a machine to operate in a specific fashion. Such non-transitory media may comprise non-volatile media and/or volatile media. Non-volatile media includes, for example, optical or magnetic disks, such as storage device 110 . Volatile media includes dynamic memory, such as main memory 106 . Common forms of non-transitory media include, for example, a floppy disk, a flexible disk, hard disk, solid state drive, magnetic tape, or any other magnetic data storage medium, a CD-ROM, any other optical data storage medium, any physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, NVRAM, any other memory chip or cartridge, and networked versions of the same.
[0068] Non-transitory media is distinct from but may be used in conjunction with transmission media. Transmission media participates in transferring information between non-transitory media. For example, transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise bus 102 . Transmission media can also take the form of acoustic or light waves, such as those generated during radio-wave and infra-red data communications.
[0069] Various forms of media may be involved in carrying one or more sequences of one or more instructions to processor 104 for execution. For example, the instructions may initially be carried on a magnetic disk or solid state drive of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to computer system 100 can receive the data on the telephone line and use an infra-red transmitter to convert the data to an infra-red signal. An infra-red detector can receive the data carried in the infra-red signal and appropriate circuitry can place the data on bus 102 . Bus 102 carries the data to main memory 106 , from which processor 104 retrieves and executes the instructions. The instructions received by main memory 106 may retrieve and execute the instructions. The instructions received by main memory 106 may optionally be stored on storage device 110 either before or after execution by processor 104 .
[0070] Computer system 100 also includes a communication interface 118 coupled to bus 102 . Communication interface 118 provides a two-way data communication coupling to a network link 120 that is connected to a local network 122 . For example, communication interface 118 may be an integrated services digital network (ISDN) card, cable modem, satellite modem, or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface 118 may be a local area network (LAN) card to provide a data communication connection to a compatible LAN (or WAN component to communicate with a WAN). Wireless links may also be implemented. In any such implementation, communication interface 118 sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information.
[0071] Network link 120 typically provides data communication through one or more networks to other data devices. For example, network link 120 may provide a connection through local network 122 to a host computer 124 or to data equipment operated by an Internet Service Provider (ISP) 126 . ISP 126 in turn provides data communication services through the world wide packet data communication network now commonly referred to as the “Internet” 128 . Local network 122 and Internet 128 both use electrical, electromagnetic or optical signals that carry digital data streams. The signals through the various networks and the signals on network link 120 and through communication interface 118 , which carry the digital data to and from computer system 100 , are example forms of transmission media.
[0072] Computer system 100 can send messages and receive data, including program code, through the network(s), network link 120 and communication interface 118 . In the Internet example, a server 130 might transmit a requested code for an application program through Internet 128 , ISP 126 , local network 122 and communication interface 118 .
[0073] The received code may be executed by processor 104 as it is received, and/or stored in storage device 110 , or other non-volatile storage for later execution.
[0074] FIG. 2 is a block diagram of the computer system 100 for analyzing potentially undesirable electronic communications, as used in an embodiment. In variations, additional blocks may be included, some blocks may be removed, and/or blocks may be connected or arranged differently from what is shown.
[0075] Computer system 100 interfaces with local network 122 , described above with reference to FIG. 1 . Users 221 interact with the local network 122 , for example, for email, text messaging, newsgroups, etc. In certain embodiments, users 221 can receive electronic communications via the local network 122 . A recipient (one of the users 221 ) of an electronic communication can make a preliminary determination that the communication is a potential phishing, spam, or malicious communication and forward the communication to an administrator. For example, a company employee can forward a potential phishing, spam, or malicious email to a corporate “abuse” email account (e.g., abuse@example.org).
[0076] Computer system 100 may include computer readable storage devices. For example, computer system 100 may include electronic communications records storage device 207 . The electronic communications records storage device 207 may be configured to store records of first electronic communications to internal recipients within a local network for a period of time. As an example, the electronic communications records storage device 207 can store records of emails sent to recipients within the local network 122 over the last week or the last month or the last six months. An example can be a PROOFPOINT (Proofpoint, Inc., Sunnyvale, Calif.) log. For each of the first electronic communications, a record can reflect the “from” field corresponding to a purported author of the first electronic communication, one or more “recipient” fields corresponding to the recipients of the respective first electronic communication (e.g., a “to” field, a “cc” field, and/or a “bcc” field), and/or the subject field corresponding to a purported topic of the respected first electronic communication. An electronic communications record need not be an email itself. This term is a broad term and encompasses subsets of data about electronic communications. For example, the term encompasses certain metadata regarding emails.
[0077] Computer system 100 may further include electronic communications storage device 203 . The electronic communications storage device 203 may be configured to store a plurality of prescreened electronic communications. As an example, the electronic communications storage device 203 can store prescreened emails. In at least one embodiment, each prescreened electronic communication is preliminarily identified as a potential undesirable electronic communication.
[0078] As used herein, the term prescreened electronic communication refers to an electronic communication that has been reviewed and identified as potentially having a certain characteristic or characteristics. The review need not be detailed or performed by someone with special training. For example, the initial recipient of the electronic communication can perform the prescreening. In this regard, a prescreened electronic communication can refer to an email that has been reviewed by its human recipient and judged or identified as a potentially undesirable electronic communication. In other instances, as noted above, the prescreening can occur without human intervention, for example, with applied rules or a suitable program. A company employee can forward a potential phishing, spam, or malicious email to an abuse account. Fourth access module 227 and/or another suitable module interfacing with the local network 122 can execute a suitable script to download the emails in the abuse email account to a computer folder or subfolder or other database as text-formatted file, such as an .eml file. The computer folder, subfolder, or other database can represent an example of electronic communications storage device 203 , discussed above. Each prescreened electronic communication in the electronic communications storage device 203 can include a from field, one or more recipient fields, a subject field, and/or a message body.
[0079] Computer system 100 may include one or more modules which may be implemented as software or hardware. For example, computer system 100 may include first access module 201 . The first access module 201 may be configured to access, from the electronic communications storage device 203 , the plurality of prescreened electronic communications. Computer system 100 may include second access module 205 . The second access module 205 may be configured to access, from the electronic communications records storage device 207 , the records.
[0080] Computer system 100 may include grouping module 211 . Grouping module 211 of computer system 100 may be configured to group, from the plurality of prescreened electronic communication, a data cluster of the prescreened electronic communications. A data cluster may be generated, determined, and/or selected from one or more sets of electronic communications according to a cluster generation strategy. A data cluster may further be generated, determined, and/or selected based on a seed. For example, seeds may comprise emails received within a time or date range, such as the last 24 hours. Electronic communications related to the seeds may be determined and added to the cluster. Further, additional electronic communications related to any clustered electronic communication may also be added to the cluster iteratively as indicated by a cluster generation strategy. Electronic communications may be related by any common and/or similar properties, metadata, types, relationships, and/or the like. Data clusters may also be referred to herein as “clustered data structures,” “electronic communication clusters,” and “clusters.” Data clusters are described in further detail in U.S. patent application Ser. No. 14/579,752 and U.S. Pat. No. 8,788,405, which have been incorporated herein by reference in their entireties.
[0081] In at least one embodiment, the prescreened electronic communications of a data cluster share a similar from field and/or a similar subject field. For example, the grouping module 211 can identify an initial electronic communication and its from field and/or its subject field. The grouping module 211 may identify additional electronic communications with similar from fields and/or similar subject fields and add them to the cluster. In at least one embodiment, the grouping module 211 identifies electronic communications having the same from field. Alternatively, or in conjunction, the grouping module 211 can identify electronic communications having from fields with similar characteristics. For instance, the grouping module 211 can implement regular expression matching or another suitable pattern recognition algorithm to identify email addresses having the same local part (the part before the “@” symbol), even if the email addresses have different domain parts (the part after the “@” symbol). Or the grouping module 211 can identify email addresses having similar patterns, such as abc1def@example.com, bcd2efg@example.com, and cde3fgh@example.com. As yet another example, grouping module 211 can identify electronic communications having the same subject field. Alternatively, or in conjunction the grouping module 211 can identify electronic communications having subject fields with similar characteristics. For instance the grouping module 211 can identify email subjects following a pattern, such as “<Varying Bank Name>: Online Banking Security Precaution,” using a suitable technique such as regular expression matching.
[0082] Other suitable techniques for identifying additional electronic communications with similar from fields and/or similar subject fields and adding them to the cluster with the grouping module 211 are also contemplated. Yet another example of such grouping can include grouping based on similar edit distances. Edit distance is a technique of quantifying how dissimilar two strings (such as words) are to one another by counting the minimum number of operations required to transform one string into the other.
[0083] Optionally, computer system 100 may further include an identification module 213 . The identification module 213 of computer system 100 may identify additional recipients associated with the data cluster. As noted above, a data cluster comprises prescreened electronic communications. The additional recipients need not be associated with prescreened electronic communications. For example, many recipients within a local network may receive similar emails and some of those recipients may report the emails as potential phishing communications to an administrator. Some recipients may not report the emails to anyone, however.
[0084] In this regard, the additional recipients can be identified in the records accessed by second access module 205 or in another electronic communications storage device (not shown). For example, identification module 213 can identify the subject field of the prescreened electronic communications or a substring within the subject field of the prescreened electronic communications, such as the first, middle, or last n characters. Then, the identification module 213 can access electronic communications records storage device 207 (optionally via second access module 205 ) and identify additional electronic communications having the same subject field or substring. Based on the subject fields of the identified additional electronic communications, the identification module 213 can determine additional recipients of those additional electronic communications corresponding with the associated to, cc, or bcc fields.
[0085] Computer system 100 may include an optional classification module 215 . Classification module 215 of computer system 100 may be configured to classify, based on one or more attributes of the data cluster, the data cluster with a classification reflecting a priority for assessing whether the prescreened electronic communications associated with the data cluster are undesirable electronic communications. Advantageously, the classification module 215 is configured such that, once initiated, the classifying is performed by the one or more hardware computer processors, without the need for manually performing the classifying.
[0086] For instance, in one embodiment, classification module 215 can automatically determine a rank or status of a recipient of a prescreened electronic communication in a data cluster without requiring user intervention. As an example, classification module can identify an employee identification number associated with a recipient, cross reference the employee identification number against an organizational database for the local network, and determine the recipient's rank. The relevant information, such as the employee identification number and rank, can be stored to the data cluster dossier. A data cluster including a recipient with a sufficiently high rank or status, such as a C suite officer or critical employee, may be assigned classification reflecting a high priority for assessing whether the prescreened electronic communications associated with the data cluster are undesirable electronic communications.
[0087] Computer system 100 may also include a parsing module 217 . As discussed above, each prescreened electronic communication can comprise a message body in some embodiments. Parsing module 217 of computer system 217 may be configured to parse, for one or more of the electronic communications in the data cluster, the respective message body for certain strings, such as uniform resource locators.
[0088] Computer system 100 may include a user interface module 219 . The user interface module 219 can be configured to generate user interface data for rendering an interactive user interface on a computing device. The user interface module 219 can also be configured to update the user interface data. User interface module 219 may include one or more modules configured to generate user interfaces, such as web pages, desktop applications, mobile interfaces, voice interfaces, and the like. The user interface module 219 may invoke the above described modules in order to make calculations to be presented to individuals. The user interface module 219 may present data via network. The user interface module 219 may further receive input from individuals so that the input may be provided to the appropriate modules and/or stored.
[0089] Computer system can optionally interact with a proxy log 225 via the local network 122 . In general, the proxy log 225 is produced by a local network proxy server and gives detailed information about the URLs accessed by specific users 221 . In various embodiment discussed herein, fourth access module 227 and/or another suitable module interfacing with the local network 122 can execute a suitable script to search the proxy log for a particular URL or IP address and determine which users 221 (if any) have accessed the URL.
[0090] Computer system 100 is also configured to interface with DNSBL or RBL 128 or other blacklist. DNSBL stands for a DNS-based Blackhole List, and RBL stands for Real-time Blackhole List. These are “blacklists” of locations on the Internet reputed to send email spam or other undesirable electronic communications. In computing, a blacklist is a basic access control mechanism for allowing through elements, except those explicitly mentioned in the list. Those items on the list are denied access. Third access module 209 can be used to interface with third party vendor's DNSBL or RBL 128 or other blacklist via Internet 223 . For example, as described in greater detail below, third access module 209 can be instructed to check an IP address against DNSBL or RBL 128 or other blacklist, such as dnsbl.example.net. The third access module 209 can take the IP access (such as 192.168.42.23) and reverse the order of the octets (23.42.168.192). The third access module 209 can then append the domain name of DNSBL or RBL 128 or other blacklist, yielding 23.42.168.192.dnsbl.example.net. Subsequently, the third access module 209 can look up this name in the DNS as a domain name. The query will either return an address, indicating that the IP address is blacklisted or a no-such-domain code (such as NXDOMAIN), indicating that the IP address is not blacklisted. If the IP address is listed, the third access module 209 optionally can look up why the IP address is listed as a text record, a function supported by most blacklist services.
[0091] II. Implementation Methods
[0092] FIG. 3 shows an example method for implementing computer system 100 of FIG. 2 , namely, a process of analyzing potentially undesirable electronic communications. In box 301 , computer system 100 accesses electronic communications. Box 301 of FIG. 3 can be implemented with first access module 201 and second access module 205 of FIG. 2 . In an example embodiment, a script is executed to generate the initial seeds for generating collections of clusters of related data from the seeds, as described in U.S. Pat. No. 8,788,405, incorporated herein by reference. The seeds can be, for instance, a time or date range of emails to target. The script can update the seeds each run to have the time or date range be, for example, the last 24-hour window.
[0093] In box 303 a , computer system 100 identifies electronic communications with similar from fields. In box 303 b , computer system 100 identifies electronic communications with similar subject fields. As discussed with reference to FIG. 2 , box 303 a in box 303 b can be implemented with identification module 213 . It should be clear that computer system 100 does not necessarily have to implement both box 303 a and box 303 b in the method. They can be implemented in the alternative. In box 305 , computer system 100 groups similar electronic communications in a data cluster. Box 305 can be implemented with grouping module 211 . For example, a cluster strategy, as described in U.S. Pat. No. 8,788,405, can be executed. The cluster strategy can process new emails, that is, emails received within the last 24 hours. The cluster strategy loads any data cluster object that has been modified in the last day. In other embodiments, the cluster strategy can load any data cluster object previously marked as malicious, which may encompass emails received greater than 24 hours in the past. For each new email, the strategy checks whether that email is already part of a data cluster. The strategy can merge the email with an existing data cluster based on subject. Emails that are not part of a data cluster generate new data clusters that eventually can be linked to other emails with similar subjects, senders, etc. Linking emails can be based off an identification property number for the data cluster. A data cluster can include information such as the submitter(s), recipients, external senders, subjects, and any URLs for the associated potentially undesirable electronic communications, as well as the body of the relevant email(s). A dossier can be created for each data cluster. The dossier comprises additional information besides the information from the potentially undesirable electronic communications that is relevant during analyst triage.
[0094] In box 307 , computer system 100 classifies the data cluster. Box 307 can be implemented with classification module 215 . An example classification is a priority tier, reflecting a priority for assessing whether the potentially undesirable electronic communications associated with the data cluster are actually undesirable electronic communications. The classification can be performed without the need for manual user intervention.
[0095] A factor in the classification algorithm can include the number of potentially undesirable electronic communications that are in the data cluster. Certain embodiments include the inventive realization that multiple similar potentially undesirable electronic communications submitted to an abuse account are more likely to be undesirable electronic communications than single instance electronic communications submitted to the abuse account.
[0096] Another factor in the classification algorithm can include whether the data cluster comprises any URLs on a DNSBL and/or RBL or other blacklist. Certain embodiments include the inventive realization that a data cluster including a URL on a DNSBL and/or RBL or other blacklist is more likely to be associated with undesirable electronic communications than a data cluster that does not include URLs or any identified URLs are not on a DNSBL and/or RBL or other blacklist.
[0097] Another factor in the classification algorithm can include whether the data cluster is associated a recipient with a sufficiently high rank or status, such as a C suite officer or critical employee. For example, it is important to identify phishing attacks targeting high ranking individuals in a local network, as compromised information can affect the local network's integrity. The identified tiers can be classified as desired. For example, tier 0 may be defined to relate to the highest priority data clusters (those most likely to be phishing or malicious communication) while tier 3 relates to the lowest priority data clusters (those most likely to be spam communications).
[0098] In box 309 , computer system 100 generates a user interface with at least one selectable element reflecting the classification. And in box 311 , computer system 100 updates the user interface with information regarding the data cluster. Box 309 and box 311 can be implemented with user interface module 219 . For example, an analyst can review a dossier associated with a data cluster in a tier 0 classification and determine if the associated data cluster is malicious, phishing, spam, or a legitimate communication. The analyst assigns the dossier a status. The status is transferred to the data cluster. The analyst can mark entire clusters as legitimate or not.
[0099] FIG. 4 shows another example method for implementing computer system 100 of FIG. 2 , namely, a process of taking action based on potentially undesirable electronic communications. In box 401 , computer system 100 displays a user interface with information regarding data cluster to user. In box 403 , computer system 100 receives a disposition regarding the data cluster from a user. In box 405 computer system 100 transmits electronic notification based on the disposition. For example, a network administrator can execute a script to identify data clusters that were recently updated with a status. The script can identify all recipients associated in the dossier (including recipients who did not report the electronic communication to an abuse account) and send the recipients an email indicating the received electronic communication was a phishing, malicious, or other high-risk communication. In certain embodiments, when a new recipient reports an electronic communication as potentially undesirable and the cluster strategy merges the electronic communication with an existing data cluster already assigned a status, the script will send the new recipient a notification.
[0100] FIG. 5 shows another example method for implementing computer system 100 of FIG. 2 , namely, a process of analyzing potentially undesirable electronic communications and taking action based thereon. In box 501 , the computer system 100 accesses electronic communication records. In box 503 , computer system 100 identifies additional recipients associated with the data cluster. For example, PROOFPOINT logs can be searched for emails with similar subjects. This search identifies additional recipients that received potentially undesirable electronic communications but did not report them to the abuse account discussed above. The additional recipients and/or relevant PROOFPOINT log entries can be added to the data cluster dossier. In box 505 , computer system 100 updates the user interface with informational data reflecting the additional recipients. In box 507 , computer system 100 transmits an electronic notification to additional recipients based on the disposition.
[0101] FIG. 6 shows yet another example method for implementing computer system 100 of FIG. 2 , namely, a process of analyzing potentially undesirable electronic communications. In box 601 , computer system 100 parses electronic communications in the data cluster for any URLs. In box 603 , computer system 100 displays a user interface with information regarding the presence of any URLs. In box 611 , computer system 100 accesses the proxy log. In box 613 , computer system 100 determines whether the parsed URLs have been accessed by any users of the local network. In box 615 computer system 100 displays on the user interface information regarding the presence of any accessed URLs. For example, the local network proxy log can be searched for traffic to any URLs identified in the emails in the data cluster. This search identifies any members of the local network who visited a potentially malicious website by clicking on a URL in an email. These “clickers” can be added to the data cluster dossier.
[0102] In box 605 , computer system 100 accesses one or more DNSBLs and/or RBLs or other blacklists. In box 607 , computer system 100 determines whether the parsed URLs are on a DNSBL and/or RBL or other blacklist. In box 609 , computer system 100 displays on the user interface information regarding the presence of blacklist URLs.
[0103] FIG. 7 shows a data cluster analysis user interface in which multiple data clusters are prioritized. The interactive user interface (generated with user interface module 219 of FIG. 2 ) can include an element selectable by a user. This example includes four selectable elements, labeled tier 0, tier 1, tier 2, and tier 3. Here, the selectable elements relate to classifications reflecting the priority for assessing whether the prescreened electronic communications associated with data clusters are undesirable electronic communications.
[0104] A user selects a selectable element with a suitable input device such as a mouse, finger, or stylus. FIG. 8 shows a data cluster analysis user interface showing potentially undesirable electronic communications for a high priority group of data clusters. Turning next to FIG. 8 , the user has selected tier 0. The interactive user interface shown in FIG. 8 has been updated to show a list of data clusters associated with that tier. For example, the first item in the list shows a data cluster comprising one prescreened electronic communication with the subject field “ACTION REQUIRED BY Friday April 17 2015—FINAL REQUEST.” The second item in the list shows a data cluster comprising one prescreened electronic communication with the subject field “Employment Ref: QMK2015-2020-1XQM.” The third item in the list shows a data cluster comprising eight prescreened electronic communications with subject fields like “Review Secured Access.”
[0105] FIG. 8 also demonstrates certain aspects of the system's front-end filtering capabilities. The left-most column of FIG. 8 shows example metadata fields or filters that are filterable for each cluster. For example, a user can filter clusters based of a specific sender, rather than conducting tiled-tier filtering. A search bar in the upper-right corner of FIG. 8 allows for similar metadata search.
[0106] A user selects the third item in the list (the third data cluster) with a suitable input device. FIGS. 9-13 shows various aspects of a dossier analysis user interface showing informational data regarding a data cluster, here, the third data cluster. The interactive user interface shown in FIG. 9 has been updated to show informational data associated with the third data cluster. In this example, the interactive user interface displays a summary tab showing information such as who sent the prescreened electronic communications in the data cluster to the local network, who in the local network submitted it, which URLs were found in the prescreened electronic communications, which attachments were found in the prescreened electronic communications, and/or whether any of the URLs were found in a DNSBL and/or RBL or other blacklist. Here, the summary tab shows the prescreened electronic communications in the data cluster contain 61 total URLs and one attachment. Two of the URLs were found in a DNSBL and/or RBL or other blacklist, here the RISKIQ blacklist (RiskIQ, Inc., San Francisco, Calif.).
[0107] The user can select a messages tab with a suitable input device to have additional information data displayed on the user interface. The interactive user interface shown in FIG. 10 has been updated to show additional informational data associated with the third data cluster. In this example, the messages tab shows textual data, such as the message body, of prescreened electronic communications in the data cluster.
[0108] The user can select a clickers tab with a suitable input device to have additional information data displayed on the user interface. The interactive user interface shown in FIG. 11 has been updated to show additional informational data associated with the third data cluster. In this example, the clickers tab shows the result of searching the proxy log for the URLs associated with the data cluster to see who in the local network clicked on the links. The NAME field reflects the name of the user who accessed the URL. The NBID field reflects an identification number associated with the user. The BAND field reflects the user's rank or status within the local network, with a lower BAND number reflecting a higher ranking user. The NAME, NBID, and BAND can be stored in and retrieved from the data cluster dossier, as discussed.
[0109] The user can also select a recipients tab with a suitable input device to have additional information data displayed on the user interface. The interactive user interface shown in FIG. 12 has been updated to show additional informational data associated with the third data cluster. In this example, the recipients tab shows the result of searching electronic communications storage device 203 (such as a PROOFPOINT log) to identify recipients in the local network received electronic communications similar to the prescreened electronic communications, in addition to those recipients who reported the prescreened electronic communications to an administrator.
[0110] The user can also select a raw data option with a suitable input device to have additional information data displayed on the user interface. The interactive user interface shown in FIG. 13 has been updated to show additional informational data associated with the third data cluster. In this example, the raw data shows PROOFPOINT logs.
[0111] Turning next to FIGS. 14A and 14B , which show dossier analysis user interfaces showing informational data regarding a data cluster, once a data cluster is analyzed, an analyst gives the data cluster a status, such as “legitimate,” “spam,” “phishing,” or “malicious.” Depending on the status, recipients are notified, such as by email, informing the recipients not to enter their credentials or informing the recipients the prescreened electronic communications is legitimate and can be responded to. As noted above, in various embodiments, a recipient need not have reported a potentially undesirable electronic communication (e.g., to an abuse account) to receive the notification. It should also be understood that, in certain embodiments, a recipient can receive such a notification even if the potentially undesirable electronic communication received does not match all of the characteristics in the initial cluster in all respects. For example, a recipient may receive a notification if the recipient received an email from the same sender, with a slightly different subject but including the same phishing link, or variation on that phishing link and/or similar language.
[0112] All recipients associated with a data cluster can be identified (such as using PROOFPOINT logs) and stored in the data cluster dossier. The dossier can be cross-referenced for the notification. In yet another example, a seed email might lead to one hundred nearly identical emails being identified, but based on the characteristics of those emails, it may be discovered that there are other shared attributes among those that end up expanding the volume of potential spam that is captured. For example, email 1 is from sender A, with subject line B and link C. That link might show up in emails from a different sender D who does not use the same subject B. Nevertheless, the system would still recognize the emails are relevant because of the link. Then, the system can analyze emails with subject B and recognize that sender A is also using a third link and then cross reference and discover other senders using that different link.
[0113] III. Terminology
[0114] Each of the processes, methods, and algorithms described in the preceding sections may be embodied in, and fully or partially automated by, code modules executed by one or more computer systems or computer processors comprising computer hardware. The processes and algorithms may be implemented partially or wholly in application-specific circuitry.
[0115] The various features and processes described above may be used independently of one another, or may be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of this disclosure. In addition, certain method or process blocks may be omitted in some implementations. The methods and processes described herein are also not limited to any particular sequence, and the blocks or states relating thereto can be performed in other sequences that are appropriate. For example, described blocks or states may be performed in an order other than that specifically disclosed, or multiple blocks or states may be combined in a single block or state. The example blocks or states may be performed in serial, in parallel, or in some other manner. Blocks or states may be added to or removed from the disclosed example embodiments. The example systems and components described herein may be configured differently than described. For example, elements may be added to, removed from, or rearranged compared to the disclosed example embodiments. In addition, the inventions illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.
[0116] Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment.
[0117] Any process descriptions, elements, or blocks in the flow diagrams described herein and/or depicted in the attached figures should be understood as potentially representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process. Alternate implementations are included within the scope of the embodiments described herein in which elements or functions may be deleted, executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those skilled in the art.
[0118] It should be emphasized that many variations and modifications may be made to the above-described embodiments, the elements of which are to be understood as being among other acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure. The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the invention can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the invention with which that terminology is associated. The scope of the invention should therefore be construed in accordance with the appended claims and any equivalents thereof.
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A data analysis system receives potentially undesirable electronic communications and automatically groups them in computationally-efficient data clusters, automatically analyze those data clusters, automatically tags and groups those data clusters, and provides results of the automated analysis and grouping in an optimized way to an analyst. The automated analysis of the data clusters may include an automated application of various criteria or rules so as to generate an ordered display of the groups of related data clusters such that the analyst may quickly and efficiently evaluate the groups of data clusters. In particular, the groups of data clusters may be dynamically re-grouped and/or filtered in an interactive user interface so as to enable an analyst to quickly navigate among information associated with various groups of data clusters and efficiently evaluate those data clusters.
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RELATED APPLICATION DATA
This application claims priority of U.S. Provisional Application No. 60/645,401 filed on Jan. 19, 2005, which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
The present invention relates to medical instruments and, more particularly, to an apparatus and method for identifying pre-calibrated reusable instruments.
BACKGROUND OF THE INVENTION
Instruments that can perform a registering procedure generally include a fixed marker arrangement with passive or active markers, wherein the geometry of the marker arrangement can be identified by a navigation system. Using the geometry of the marker arrangement, it is possible to deduce the type or nature of the instrument. Various registering instruments exist for various applications, wherein each instrument is individually calibrated and must be registered or identified by the navigation system.
SUMMARY OF THE INVENTION
A pre-calibrated reusable instrument is provided that can include a plurality of instruments, wherein the plurality of instruments can be used, for example, to register bones or the like during medical procedures, such as a surgical procedure. Markers can be arranged on the pre-calibrated instrument, and their relative position with respect to each other can be identified by a navigation system. Once identified, the navigation system can deduce a location of a tip or pre-calibrated end of the instrument and/or of the plurality of instruments.
Further, there is provided a method for identifying the state of a pre-calibrated reusable instrument, wherein a relative position of markers with respect to each other is identified. By comparing the identified marker geometry with previously stored marker geometries, it is possible to deduce which instrument of the pre-calibrated reusable instrument can or is being used and/or is protruding from a casing, for example.
As used herein, pre-calibrating is understood to mean that the geometry of the reusable instrument is known or that data describing the geometry of the reusable instrument is known, wherein the known geometry and/or data are provided to or ascertained by a navigation system (or software of the navigation system) and can be stored in memory (e.g., a memory buffer). The data can include: positional and/or length details that, for example, identify the tips, ends or functional elements of the reusable instrument; the length of the reusable instrument; the position of the tips, ends or functional elements of the reusable instrument; and/or a shape of the tips, ends or functional elements of the reusable instrument.
The data describing the geometry of the pre-calibrated reusable instrument also can include information on the position of the markers on the pre-calibrated reusable instrument, and which marker arrangement or marker geometry corresponds to which functional element. The data can further include a possible use of a functional element. Accordingly, a navigation system, for example, can detect a marker geometry, from which it is possible to directly deduce which of the functional elements can, are, or should be used, or the shape of the usable functional element.
The pre-calibrated reusable instrument includes an instrument holder on or in which an instrument can be arranged, wherein the instrument can be moved relative to the instrument holder. The pre-calibrated instrument can further include at least three markers (e.g., active and/or passive markers), wherein at least one of the markers can be moved together with the instrument relative to the instrument holder. Thus, at least one of the markers can be connected to the instrument or arranged directly on the instrument, for example, such that the marker can be moved by a vector of the same direction and magnitude as the instrument, or such that the distances by which the marker and the instrument are shifted correspond in terms of direction and length. At least two of the markers can be connected to the instrument holder or can be fixedly or immovably arranged directly on the instrument holder, such that when the instrument is shifted relative to the instrument holder, the instrument and the marker connected to the instrument can perform a movement relative to the instrument holder and the at least two markers connected to the instrument holder.
The instrument can include at least two functional elements, such that the instrument exhibits the same functionality as at least two instruments each having one functional element or unit, wherein the functional elements of the instrument are preferably configured differently. The instrument can be held by the instrument holder and can be moved relative to the instrument holder and/or relative to the at least two markers connected to the instrument holder. The instrument holder can be configured as a hollow cylinder, wherein the instrument can be in the hollow or interior portion of the cylinder. Preferably, the instrument is mounted within the instrument holder such that it can be shifted with respect to the instrument holder. Further, the instrument also can be shifted along a longitudinal axis of the pre-calibrated reusable instrument or the instrument holder (e.g., along the longitudinal axis of the hollow cylindrical instrument holder). The instrument holder also can serve as a grip for the pre-calibrated reusable instrument.
The instrument, for example, together with the at least one marker connected to the instrument, can be moved or shifted relative to the instrument holder and/or relative to the markers connected to the instrument holder, wherein the instrument can be mounted non-rotatably in the instrument holder. This can ensure that movement of the instrument relative to the instrument holder is substantially constant and, in particular, that a translational movement is substantially constant and repeatable (e.g., moving or shifting is accomplished with tight positional tolerances).
The instrument, which preferably lies in the instrument holder, can be moved relative to the instrument holder into two fixed end states wherein, for example, the instrument locks in the end states and cannot be further moved or shifted until the end state is released (e.g., releasing a latch), at which point the instrument can be moved again. In particular, the end states of the instrument can be safety-locked, such that the instrument cannot be moved as long as the safety lock is activated or set, and can only be shifted relative to the instrument holder once the safety lock has been deactivated or released. The at least two functional elements of the instrument can be identical, similar or different, can have the same, similar or different functionality, and can be pre-calibrated. It can be known that the functional elements perform a particular function, can be situated on the instrument, or which functional element can, is or should be used with a particular marker arrangement or geometry. Thus, for example, a navigation system can detect or identify the respective marker geometry and can deduce from the marker geometry (wherein at least two markers can be connected to the instrument holder and at least one marker can be connected to the instrument) which functional element should be used or which functional element can be used or is available for use.
If, for example, two markers (e.g., active and/or passive markers) are connected to the instrument holder, and if one marker is connected to the instrument and the instrument includes two functional elements, then in one state of the pre-calibrated reusable instrument (e.g., in one fixed end state) the markers can form a particular marker geometry that indicates which of the two functional elements should be used or is ready to be used, for example. In a second state of the pre-calibrated reusable instrument, the markers can form another particular geometry, from which it can be deduced that the second functional element can be used or is ready to be used.
A registering procedure using the pre-calibrated reusable instrument can be performed wherein the reusable instrument is detected by a camera, such as an infrared camera, for example. The spatial position of the pre-calibrated reusable instrument can be ascertained, thereby enabling use of the at least two functional elements (which can have different shapes and can be used for registering different parts of the body, such as different bones or bone shapes) as registering instruments. A registering apparatus such as the pre-calibrated reusable instrument can be sufficient for performing various or multiple tasks. In contrast, conventional methods require the use of a number of instruments, such as registering apparatus or pointers, each of which have to be individually registered prior to use for registering bones or bone contours. The pre-calibrated reusable instrument, for example, is registered once. Thereafter, the pre-calibrated reusable instrument can be navigated by a navigation system, wherein due to the marker geometry, the navigation system and/or a computational unit can identify which functional element of the pre-calibrated reusable instrument is or should be used. Since all the functional elements are pre-calibrated, the functional element provided for use can be used for registering bones or bone contours. A calibrating procedure also can be sufficient to calibrate the reusable instrument together with the at least two functional elements, whereas when using a number of instruments each having one functional element, each instrument has to be individually calibrated.
The at least two functional elements of the instrument can be formed on the ends or tips of the instrument (e.g., as identical or different tips of an elongated or rod-shaped instrument that can be moved relative to the instrument holder into at least two fixed or invariable end states). In the at least two fixed end states of the instrument, at least one of the at least two functional elements, such as for example the tips of the instrument, can be protected by the instrument holder (e.g., by the instrument holder surrounding the functional element or the tips by the protected tip or functional element being situated in the interior of the instrument holder). The non-protected functional element or elements can be used for registration procedures. Particularly, only one of the functional elements or only one of the tips can be used in each end state, while the remaining functional elements may be protected by the instrument holder and may not be used.
At least one of the markers can be connected to the instrument or can be arranged directly on the instrument, and at least two markers can be connected to the instrument holder or arranged on the instrument holder. At least one marker arranged on the instrument can be shifted along a longitudinal axis of the pre-calibrated reusable instrument or instrument holder, in particular together with the instrument, and thus change its position relative to the at least two markers arranged on the instrument holder. From the new position of the at least one marker arranged on the instrument relative to at least two markers arranged (preferably fixed) on the instrument holder, it is possible to deduce which functional element or elements can or are being used. In other words, it can be deduced which functional elements are not protected by the instrument holder, or which functional elements cannot be used because they are surrounded or protected by the instrument holder.
In a first end state of the instrument, in which the instrument preferably can not be moved relative to the instrument holder, the at least three markers can form a triangle or polygon, wherein the triangle is not congruent to a triangle formed by the at least three markers in a second end state of the instrument. Due to the difference between the triangles or polygons or the difference in the geometry of the marker arrangement in the end states, a navigation system can ascertain the state of the reusable instrument, and ascertain and/or deduce from this which functional element of the instrument can be or is being used.
In a method for identifying the state of the pre-calibrated reusable instrument, one of at least two possible states or one of at least two possible marker geometries of the reusable instrument can be identified. The identified or current state or the identified or current marker geometry can be ascertained by means of stored information on the geometry of the pre-calibrated reusable instrument. For example, by comparing the current state or the current marker geometry with a plurality of known or stored marker geometries that can be stored in a database or memory, for example, it is possible to deduce which of the functional elements can be or is being used.
The invention further provides a computer program which, when it is loaded onto a computer or is running on a computer, performs a method as described above. The invention also provides a program storage medium or computer program product comprising such a program.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an exemplary pre-calibrated reusable instrument in accordance with the invention, in a first state.
FIG. 2 illustrates the pre-calibrated reusable instrument of FIG. 1 , in a second state.
FIG. 3 is a block diagram of a navigation system that can be used with the invention.
FIG. 4 is a block diagram of a computer system that can be used to implement the method of the present invention.
DETAILED DESCRIPTION
FIG. 1 shows an exemplary pre-calibrated reusable instrument 1 that includes a hollow cylindrical instrument holder 2 and a rod-shaped instrument 3 within the holder 2 . The instrument 3 includes tips 4 , 5 having different shapes, wherein the tips are located at distal ends of the instrument. The tips 4 , 5 have a different functionality from one another and can be used before, during, or after surgery for registering different points on the body or bone contours, for example. The instrument 3 can be a pointer instrument wherein the tips 4 , 5 can travel or scan and register bodies, such as parts of a patient's body or bones. Due to the different shape of the tips 4 , 5 of the pointer instrument, the tips 4 , 5 can be used for different tasks, such as registering different contours, bones or parts of the body, such that the instrument 1 having the two-tip pointer has the same functionality as two individual pointers each having one tip.
Two passive or active markers 6 , 7 are attached to the instrument holder 2 at positions A and C, while one marker 8 is attached to the instrument 3 . In the position or end state B 1 of the marker 8 , the three markers 6 , 7 , 8 form a triangle AB 1 C, if one imagines the markers 6 , 7 , 8 connected. In the fixed end state B 1 of the marker 8 , the marker 8 is preferably locked, latched or safety-locked, such that it can only be moved when a latch or safety lock has been released. As can be seen in FIG. 1 , one tip 5 of the instrument 3 lies fully in the instrument holder 2 or is surrounded by the instrument holder and, thus, is protected from being touched, damaged or broken. While the tip 5 lies in or is protected by the instrument holder, the other tip 4 can be used for a registration procedure.
The particular tip 4 , 5 being used is defined by the geometry of the marker arrangement, in particular by the triangle AB 1 C formed by the markers 6 , 7 , 8 . The marker arrangement can be detected by a navigation system, for example, and compared with known marker arrangements, such as triangular shapes. This comparison can be performed in a computational unit, for example, such as a computer. Based on the comparison of the current state or the current marker geometry with known states or marker geometries, it is possible to ascertain which tip 4 , 5 of the pointer or instrument 3 is being used for registration, so as to take into account specific data of the tip 4 , which can be used when registering a body or part of a body such as a bone.
FIG. 2 shows the pre-calibrated reusable instrument from FIG. 1 in a second, preferably fixed or safety-locked end state B 2 of the marker 8 , wherein the marker arrangement from FIG. 2 can be distinguished from the marker arrangement from FIG. 1 from any spatial direction. The triangle AB 2 C from FIG. 2 , formed by the three markers 6 , 7 , 8 , is not congruent with the triangle AB 1 C of the marker arrangement from FIG. 1 . More specifically, when viewed from any spatial point, the different sides of the two triangles AB 1 C and AB 2 C can be determined or and/or different angles of the two triangles AB 1 C and AB 2 C can be seen. It is therefore possible, from any spatial point, to clearly distinguish which position, in particular which fixed end state, the marker 8 is situated. From the determined marker position, it is possible to deduce which of the two tips 4 , 5 of the pointer or instrument 3 has been extended from the instrument holder 2 or which of the two tips 4 , 5 is lying in the instrument holder 2 . Further, due to the different shapes of the tips 4 , 5 , it is possible to deduce which data should be taken into account during a registration procedure, in particular in the calculations of the computational unit.
FIG. 3 illustrates a navigation system 10 that can be used to navigate or track the pre-calibrated reusable instrument 1 . The navigation system 10 includes cameras 12 , such as infrared cameras, operatively coupled to a computational unit 14 . The cameras 12 collect spatial data of the markers 6 , 7 , 8 , and provide this data to the computational unit 14 . Using the data, the computational unit 14 ascertains a position in three-dimensional space of the markers and there relative locations with respect to each other. Based on the relative location of the markers, the computational unit ascertains which tip 4 , 5 is within the instrument holder 2 and which tip 4 , 5 is extended from the instrument holder 2 . Further, the navigational system can track the location in three-dimensional space of the tips 4 , 5 , which then can be used to register a body part, for example.
Moving to FIG. 4 , the computational unit 14 for executing a computer program in accordance with the present invention is illustrated in more detail. The computational unit 14 includes a computer 20 for processing data, and a display 22 (e.g., a Cathode Ray Tube, Liquid Crystal Display, or the like) for viewing system information. A keyboard 24 and pointing device 26 may be used for data entry, data display, screen navigation, etc. The keyboard 24 and pointing device 26 may be separate from the computer 20 or they may be integral to it. A computer mouse or other device that points to or otherwise identifies a location, action, etc., e.g., by a point and click method or some other method, are examples of a pointing device. Alternatively, a touch screen (not shown) may be used in place of the keyboard 24 and pointing device 26 . Touch screens may be beneficial when the available space for a keyboard 24 and/or a pointing device 26 is limited.
Included in the computer 20 is a storage medium 28 for storing information, such as application data, screen information, programs, etc. The storage medium 28 may be a hard drive, an optical drive, or the like. A processor 30 , such as an AMD Athlon 64™ processor or an Intel Pentium IV® processor, combined with a memory 32 and the storage medium 28 execute programs to perform various functions, such as data entry, numerical calculations, screen display, system setup, etc. A network interface card (NIC) 34 allows the computer 20 to communicate with external devices.
The actual code for performing the functions described herein can be readily programmed by a person having ordinary skill in the art of computer programming in any of a number of conventional programming languages based on the disclosure herein. Consequently, further detail as to the particular code itself has been omitted for sake of brevity.
Although the invention has been shown and described with respect to a certain preferred embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.
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A pre-calibrated reusable instrument includes an instrument holder and an instrument held by and movable with respect to the instrument holder. The instrument includes at least two functional elements and at least three markers, wherein at least one of the markers is movable with the instrument relative to the instrument holder such that a movement of the instrument produces a corresponding movement of the at least one marker.
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BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a circuit for recovering a digital signal from an input signal received by way of galvanic separation, comprising two input terminals for the input signal and one output terminal for the recovered digital signal.
In the transmission of electrical signals between two systems A and B, it is frequently required that systems A and B must not be galvanically (metallically) connected to one another, that is to say there must not be a direct metallic connection between systems A and B. To galvanically isolate systems A and B, which are intended to exchange signals with one another, the insertion of a capacitor in each of the signal transmission lines or the use of a transformer for a pair of signal lines is possible in line-connected signal transmission. Accordingly, the coupling elements of capacitor or transformer, respectively, allow the transmission of signals between systems A and B without connecting these to one another galvanically.
However, the use of the coupling elements causes a change in the signal variation so that in the transmission of a signal from system A to system B, a device must be provided in system B by means of which the signal variation originally output by system A can be recovered. This is required especially in the case of digital signals because the digital signal processing devices in the receiving system B only operate reliably with defined signal structures.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a signal regeneration circuit, which overcomes the abovementioned disadvantages of the heretofore-known devices and methods of this general type and which allows a digital signal supplied to a receiver system by way of metallic isolation to be recovered from the received signal.
With the foregoing and other objects in view there is provided, in accordance with the invention, a signal regeneration circuit for recovering a digital signal from an input signal supplied via metallic isolation, comprising:
two input terminals receiving an input signal;
one output terminal outputting a recovered digital signal; and
a current direction sensor connected to the two input terminals for detecting a current direction prevailing between the two input terminals and outputting a signal representing the prevailing current direction.
In accordance with an added feature of the invention, the current direction sensor includes a voltage clamping configuration for fixing a voltage between the input terminals and a current mirror comprising an output driver configuration outputting the signal representing the prevailing current direction.
In accordance with an additional feature of the invention, the voltage clamping configuration includes a first series circuit of at least two diodes each connected in a given direction and a second series circuit of at least two diodes each connected in a direction opposite the given direction, the first and second circuits being connected to one another at a center node.
In other words, a preferred signal regeneration circuit has a current direction sensor which detects the current direction prevailing between the input terminals and outputs a signal corresponding to the prevailing current direction. In this configuration, the current direction sensor detects the direction of the current which flows between the two input terminals. The current direction sensor preferably includes a voltage clamping configuration and a current mirror. The voltage clamping configuration fixes the voltage between the input terminals to a predetermined maximum value. The current mirror detects the current flowing between the input terminals and supplies the detected current value to an output driver configuration at which the output signal can be picked up. It is especially preferred in this configuration that the voltage clamping configuration has a first and a second series connection of in each case at least two diodes connected in the same direction. In this configuration, the diodes of the first series circuit are connected in the opposite direction to the diodes of the second series circuit, and the series circuits are connected to one another at a center node.
In accordance with another feature of the invention, the current mirror includes a first current mirror circuit and a second current mirror circuit, the first current mirror circuit reflecting a current flow through the voltage clamping configuration in a first current flow direction and the second current mirror circuit reflecting a current flow through the voltage clamping configuration in a second current flow direction.
In accordance with again an added feature of the invention, the current mirror further includes a third current mirror circuit and a fourth current mirror circuit, the third current mirror circuit being connected to an output current path of the first current mirror circuit and the fourth current mirror circuit being connected to an output current path of the second current mirror circuit.
In accordance with again another feature of the invention, a connecting node connects an output current path of the third current mirror circuit with an output current path of the fourth current mirror circuit, the output current paths of the third and fourth current mirror circuits form the output driver configuration, and the connecting node outputs the output signal representing the prevailing current direction.
These foregoing features define a further, especially preferred exemplary embodiment of the signal regeneration circuit. The current mirror of the current direction sensor thereby has a first and a second current mirror circuit. In this configuration, the first current mirror circuit reflects the current flow through the voltage clamping configuration in a first current flow direction and the second current mirror circuit reflects the current flow through the voltage clamping configuration in a second current flow direction. In addition, it is especially preferred that the current mirror includes the third and fourth current mirror circuits. Here, the third current mirror circuit is connected to the output current path of the first current mirror circuit and the fourth current mirror circuit is connected to the output current path of the second current mirror circuit. The embodiment in which the output current path of the third current mirror circuit and the output current path of the fourth current mirror circuit are connected to one another and form the output driver configuration is especially preferred. The output signal can then be picked up at the connecting node of the output current paths of the third and fourth current mirror circuit.
In accordance with yet an added feature of the invention, the voltage clamping configuration includes a center node and a reference potential is added at the center node of the voltage clamping configuration. In this configuration, the reference potential is fixed with respect to the ground potential of the current direction sensor and thus of the signal-receiving system. The circuit structures of the current mirror can then be designed with respect to the ground potential of the receiving system.
In accordance with yet another feature of the invention, the reference potential has a value that lies within a range of threshold potentials of CMOS transistors in an integrated circuit.
In accordance with yet an additional feature of the invention, the current direction sensor is constructed with a plurality of transistors including bipolar transistors and CMOS transistors. In accordance with yet a further feature of the invention, the input signal is supplied to the inputs via capacitive coupling where capacitances are connected upstream of the two inputs in the signal flow direction.
In accordance with a concomitant feature of the invention, the current direction sensor comprises a buffer for temporarily storing a last prevailing current direction. In a preferred embodiment the buffer is constructed as a flip flop.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a signal regeneration circuit, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit schematic of a preferred exemplary embodiment of the signal regeneration circuit according to the invention; and
FIG. 2 is a circuit schematic of a novel circuit for generating a reference potential.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is seen a circuit that is essentially subdivided into four circuit blocks. A circuit block CC relates to the capacitive coupling between two signal lines. Circuit blocks VC, CM and OL together form a current direction sensor according to a preferred exemplary embodiment of the invention. The current direction sensor according to FIG. 1 includes a voltage clamping configuration VC, a current balancing configuration or current mirror CM and a buffer configuration OL. The current direction sensor is supplied via the capacitive coupling CC with a typically differential input signal that is evaluated by the current direction sensor and output as recovered input signal at its output terminal OUTPUT. The capacitive coupling configuration, in each of the signal lines, includes one coupling capacitor CHP 1 and CHP 2 and a series-connected resistor R 3 and R 4 , respectively. The free terminals of the resistors R 3 and R 4 , respectively, are connected to the input signal terminals INPUT 1 and, respectively, INPUT 2 of the voltage clamping cofiguration VC of the current direction sensor.
The voltage clamping configuration includes two series of diodes D 1 , D 2 , D 3 , D 4 and, respectively, D 5 , D 6 , D 7 , D 8 which are connected in antiparallel and which are connected at their free ends to the input signal terminals INPUT 1 and, respectively, INPUT 2 . A series circuit of resistors R 1 and R 2 is connected in parallel with the diode series circuits. The free ends of the resistor series circuit R 1 +R 2 are also connected to the signal input terminals INPUT 1 and, respectively, INPUT 2 . The two diode series circuits and the resistor series circuit are connected to one another at a center node B. The center node B is connected to a reference potential Vref which is fixed with respect to the ground potential of the receiving system. The signal input terminals INPUT 1 and, respectively, INPUT 2 are thus above and, respectively, below the reference voltage Vref by two diode conducting voltages V D with respect to the ground potential of the receiving system to which the current direction sensor belongs. In an integrated circuit, the diodes D 1 to D 8 are preferably constructed as bipolar transistors, the collector and base of which are short-circuited and thus emulate the function of a diode in a simple manner in the integrated circuit.
In the current mirror CM of the current direction sensor, the input current paths of a first and of a second current mirror circuit are connected between the center node B and the node of the input signal terminal INPUT 2 . The input current path of the first current mirror circuit includes a resistor RX and a bipolar transistor QX 1 of the npn type which is short-circuited to form a diode. The input current path of the first current mirror circuit is thus connected in the same conducting direction as the diode series circuit D 1 to D 4 . The input current path of the second current mirror circuit includes a resistor RY and a bipolar transistor QY 1 of the pnp type which is short-circuited to form a diode. Thus, the input current path of the second current mirror circuit has the same conducting direction as the diode series circuit D 5 to D 8 . The maximum current IX through the input current path of the first current mirror circuit and the maximum current IY through the input current path of the second current mirror circuit are identical in amounts. The current direction, however, is opposite in accordance with the diode switching direction. The amounts are:
[1 ]=|IX|=|IY |=(2 V D −V BE )| RX
where V D is the conducting voltage of a diode of the diode series circuits D 1 to D 8 and where V BE is the base-emitter voltage of transistor QX 1 and, respectively, QY 1 . Since V D ≈V BE ≈0.7 V, the following result is obtained:
[2 ]=|IX|=|IY|= 0.7V/ RX
whereby the resistors RX and RY have the same dimensions for reasons of symmetry. Accordingly, the same amounts of current are thus obtained for IX and IY.
In the output current path of the first current mirror circuit, the collector-emitter path of an npn transistor QX 2 is located and in the output current path of the second current mirror circuit, the collector-emitter path of a pnp transistor QY 2 is located. The base terminals and the emitter terminals of transistors QX 1 and QX 2 and of transistors QY 1 and QY 2 are connected to one another in order to form a current mirror circuit. The output current path of the first current mirror circuit is connected to the input current path of a third current mirror circuit and the output current path of the second current mirror circuit is connected to the input current path of a fourth current mirror circuit. In the input current path of the third current mirror circuit, the load path of a p-channel MOS transistor MX 1 is located. A free end of the load path of the transistor MX 1 is connected to the supply voltage terminal of the receiving system. In addition, the gate terminal of the transistor MX 1 is connected to the connecting node of the transistors QX 2 and MX 1 . Similarly, the output current path of the second current mirror circuit is connected to the input current path of a fourth current mirror circuit. In the input current path of the fourth current mirror circuit, the load path of an n-channel MOS transistor MY 1 is located, the free end of the load path being connected to the ground potential of the receiving system. The gate terminal of transistor MY 1 is connected to the connecting node of transistors QY 2 and MY 1 .
The output current path of the third current mirror circuit is formed by a p-channel MOS transistor MX 2 and the output current path of the fourth current mirror circuit is formed by the load path of an n-channel MOS transistor MY 2 . A free end of the load path of the transistor MX 2 is connected to the supply voltage terminal of the receiving system and a free end of the load path of the transistor MY 2 is connected to the ground terminal of the receiving system. The gate terminals of the transistors MX 1 and MX 2 and of transistors MY 1 and MY 2 are connected to one another in order to form a current mirror circuit. The load paths of the transistors MX 2 and MY 2 of the third and fourth current mirror circuit are connected to one another at a node S. At the node S, a logic signal can be picked up which indicates the current direction that is instantaneously prevailing between the input terminals INPUT 1 and INPUT 2 .
The current mirror CM is followed by the output buffer configuration OL in the signal flow direction. The output buffer configuration OL stabilizes the output signal at the node S of the current mirror CM. The output buffer circuit OL includes a flip flop FF consisting of CMOS inverters, the input terminal of which is connected to the output node S of the current mirror CM. One of the inverters of the flip flop FF also includes load transistors ML 1 and ML 2 which are also configured in complementary MOS technology. At the output terminal of the flip flop, three series-connected inverters A 1 , A 2 and A 3 are connected. The inverter A 3 is configured and dimensioned as a CMOS output driver. The output signal OUTPUT of the signal regeneration circuit of the invention is available at the output terminal of the inverter A 3 .
The voltage clamping configuration with the antiparallel-connected diode series circuits D 1 to D 4 and, respectively, D 5 to D 8 clamps the voltage between the signal input terminals INPUT 1 and INPUT 2 to a value which is four times a diode conducting voltage V D by amount. With respect to the center node B, the voltage at the signal input terminal INPUT 2 moves between Vref+2V D and Vref−2V D with respect to the ground potential of the receiving system. It should be mentioned at this point that in the case of a rectangular differential input signal present at capacitors CHP 1 and CHP 2 , the capacitors CHP 1 and CHP 2 discharge exponentially via resistors R 1 and, respectively, R 2 after each change in voltage level in the input signal. In this case, the current direction of the discharge current determines the logic state of the input signal. A first current direction is detected in the input current path of the first current mirror circuit and the second current direction is detected in the input current path of the second current mirror circuit. Although the input current paths of the first and second current mirror circuit according to FIG. 1 are connected between the center node B and the node of the input terminal INPUT 2 , the circuit operation can also be implemented with only a slightly different configuration if the input current path of the first or second current mirror or of the first and second current mirror is connected between the center node B and the node of the input terminal INPUT 1 .
The current IX in the input current path of the first current mirror circuit is reflected in its output current path and, at the same time, supplied to the input current path of the third current mirror circuit. Similarly, the current IY in the input current path of the second current mirror circuit is reflected in its output current path and supplied to the input current path of the fourth current mirror circuit. Since at a particular time, either only the first current mirror circuit or only the second current mirror circuit is in each case active, the output current paths of the third and fourth current mirror circuit can be connected to one another in order to pick up the output signal at the connecting node S.
If, for example, a negative input signal is present, that is to say the voltage difference between the input terminal INPUT 1 and input terminal INPUT 2 is negative and a current flows from the input terminal INPUT 2 to the input terminal INPUT 1 , a voltage which is twice a diode conducting voltage V D above the reference voltage Vref with respect to the ground potential of the receiving system is present at the input terminal INPUT 2 . Thus, a current IY calculated as above flows through the input current path of the second current mirror circuit. This current IY is reflected to the output current path of the second current mirror circuit, multiplied by the fourth current mirror circuit and applied via the node S to the flip flop FF in order to switch the state of the latter. Thus, the flip flop switches between the input terminals INPUT 1 and INPUT 2 in accordance with the currently prevailing current direction. The switching currents of the flip flop FF can be set by means of the load transistors ML 1 and ML 2 .
Referring now to FIG. 2, there is shown a circuit for generating the reference potential Vref. For this purpose, a current I B with a very low value is supplied to a node A. This current flows via npn transistors QB 1 and QB 2 , which are connected together to form diodes, and the load path of an n-channel MOS transistor away to the ground terminal of the receiving system. This results in a voltage drop of twice the base-emitter voltage V BE of transistors QB 1 and QB 2 and the threshold voltage VT of MOS transistor MB 1 . At the n-channel MOS transistor MB 2 , this current is reflected into an output current path via transistors MB 1 and MB 2 which are connected together to form a current mirror circuit. The output current path consists of the load path of transistor MB 2 , the collector-emitter path of an npn transistor QB 7 which is also connected together with transistor QB 2 to form a current mirror circuit, and the load path of a p-channel MOS transistor MB 5 . Via transistor MB 5 , the current in the output current path of the current mirror is reflected to the load path of a p-channel MOS transistor MB 6 . The latter activates a pnp transistor QB 4 and drives a further current mirror consisting of n-channel or MOS transistors MB 3 and MB 4 . In the output current path of this current mirror circuit, the load path of transistor MB 4 and the collector-emitter path of an npn transistor QB 3 is located, which, as a result, is also activated. The base of an output transistor QB 5 of the npn type is connected to a connecting node Y of transistor MB 6 and of transistor QB 4 . The base of an output transistor QB 6 of the pnp type is connected to a connecting node X between the emitter of transistor QB 3 and the load path of transistor MB 4 . The emitters of output transistors QB 5 and QB 6 are connected to one another and are at the required voltage Vref.
In this configuration, the voltage Vref is at the same magnitude as the potential at the node A. This is due to the fact that the bases of the transistors QB 3 and QB 4 are also connected to the node A and the transistors QB 3 and QB 4 are kept activated by the current mirrors of transistors MB 3 and MB 4 and, respectively, MB 5 and MB 6 . Thus, the node Y is above the potential of the node A by the voltage drop across the base-emitter diode of the transistor QB 4 . The voltage drop across the base-emitter diode of the transistor QB 5 then brings one back to the potential of the node A. The same result is obtained from the node A via the base-emitter path of the transistor QB 3 to the node X and from there via the base-emitter path of the transistor QB 6 to the output terminal Vref. Through the output stage of the transistors QB 5 and QB 6 , the reference voltage Vref can be picked up with low impedance and push-pull capability at the output terminal.
The circuit according to FIG. 2 belongs to the receiving system and, accordingly, is referred to its ground potential. This also applies to the supply voltage terminals, illustrated in FIG. 2, at the free ends of the load paths of transistors MB 5 , MB 6 , QB 3 and QB 5 . Between node A and the ground potential, a capacitor C 1 is also connected which filters out high-frequency noise from a surrounding supply voltage source or clock system sources. The voltage at node A, and thus the output voltage Vref, is twice a base-emitter voltage above the threshold voltage of a MOS transistor with respect to the ground potential of the receiving system.
The circuit according to the invention makes it possible to regenerate a differential input signal which is supplied via coupling capacitors CHP 1 and CHP 2 to the receiving system via input terminals INPUT 1 and INPUT 2 , as such referred to the ground potential of the receiving system and to output this signal at an output terminal OUTPUT. Accordingly, no direct current flows between the transmitting system and the receiving system and only an alternating-current component is transmitted. The circuit according to the invention can be constructed in a simple manner completely integrated in a semiconductor structure.
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The signal regeneration circuit recovers a digital signal from an input signal that is supplied via metallic isolation (galvanic separation). The circuit has two input terminals for the input signal and one output terminal for the recovered digital signal. A current direction sensor detects the current direction prevailing between the input terminals and outputs the signal in accordance with the last prevailing current direction. The circuit is advantageously used in connection with digital circuits that require potential isolation at their input terminals.
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The present application is the U.S. National Phase of International Application No. PCT/JP2012/063483, filed on May 25, 2012, which claims the benefit of Japanese Patent Application No. 2011-121706, filed on May 31, 2011, the entire contents of which are hereby incorporated by reference.
TECHNICAL FIELD
The present invention relates to an acoustic insulation device for a mobile vehicle such as a railway vehicle, and specifically, relates to an acoustic insulation device for a mobile vehicle that blocks the noise generated from a power collector disposed on a roof of a high-speed railway vehicle.
BACKGROUND ART
Conventionally, in railway vehicles, and especially in railway vehicles that travel at high speed, there are concerns that the noise generated in, and in the vicinity of, a device, especially a power collector, disposed on the roof of the vehicle may be increased by the increase in speed of the railway vehicles, so in order to insulate such noise, acoustic insulation bodies which are placed with a distance from the rooftop device in a width direction of the vehicle body and having a given length along the longitudinal direction of the vehicle body are provided on the roof.
On the other hand, in Shinkansen (bullet train) lines that are designed to be able to travel through conventional railway sections, such as miniature Shinkansens which travel from Shinkansen tracks directly to conventional railway lines, wherein the conventional railway lines have the track gauge converted from a narrow track for conventional railways to a standard gauge, the critical range of the vehicle body is narrow, so that the restrictions related to the width of the vehicle body or the height of the vehicle body are strict compared to Shinkansen sections, and in order to cope with such restrictions, there are demands for downsizing the device for insulating (blocking) the noise generated from the devices disposed on the roof of the vehicle.
In order to reduce or insulate the noise generated from devices such as the power collector disposed on the roof of the vehicle body of a mobile vehicle, an art of covering the vicinity of the power collector with a wind cover and providing an acoustic insulation wall for insulating noise to the outer side of the wind cover is already proposed, and an acoustic insulation device as disclosed in patent literature 1 is already proposed. In other words, an acoustic insulation device for a mobile vehicle having a simple configuration and having a high sound insulating effect is proposed, that fits within the critical range of vehicles in a conventional railway section, and that enables to ensure sufficient insulation distance between the acoustic insulation panel and the power collector. The acoustic insulation means is composed of first and second acoustic insulation bodies provided upright in a chevron-shape in a width direction of the vehicle body with respect to a device on the roof and having a predetermined length along a longitudinal direction of the vehicle body, wherein the first acoustic insulation body is arranged rearward to the second acoustic insulation body with respect to a direction of travel of the mobile vehicle.
Further, there is proposed a soundproof wall that is used as a side wall for roads, railways, factories and so on, that exerts sufficient soundproof effect not only for the nose that travels upward from a low area, but for the noise that travels downward from the upper area (patent literature 2). The soundproof wall illustrated in patent literature 2 has a first bifurcation wall that is inclined to a noise source side at an upper end of a main wall that extends upward, and a second bifurcation wall that is inclined to an opposite side from the noise source side, wherein at least one bifurcation wall out of the first and second bifurcation walls has a re-bifurcation wall that is re-bifurcated to a direction that differs from said bifurcation wall.
However, the soundproof wall taught in patent literature 2 is a soundproof wall that is provided at a fixed location such as on the ground, and there is no consideration on placing the wall on a railway vehicle that travels at a high speed. Therefore, it is difficult to apply the soundproof wall simply to a railway vehicle to realize a design that fits within the critical range of the vehicle. In addition, if there is a need to provide a means for insulating noise generated from a power collector of the railway vehicle, an insulation distance (the range of distance in which an object cannot be placed for insulation) with respect to the high voltage section of the power collector must be ensured, so that it is difficult to satisfy this request according to the method taught in patent literature 2.
In a railway vehicle, the main noise source is the power collector disposed on the roof of the vehicle. The acoustic insulation device of a mobile vehicle according to patent document 1 has been developed to block the noise generated from the power collector efficiently. The acoustic insulation device for a mobile vehicle is disposed to block the main source of noise that appears on a downstream side of the direction of flow of the noise source from an observer of the noise (or local residents) considering the direct advancing property of sound. However, sound not only has a direct advancing property, but it also has a reflecting or diffracting property. As for the noise generated from a power collector of the mobile vehicle, a portion of the noise is reflected or diffracted to come around the sound insulation wall and reaches the observer of the noise (or local residents).
CITATION LIST
Patent Literature
[PTL 1] Japanese Patent Application Laid-Open Publication No. 2009-179191
[PTL 2] Japanese Patent Application Laid-Open Publication No. 08-085921
SUMMARY OF INVENTION
Technical Problem
Therefore, the technical problem to be solved is to provide a means for blocking the noise being reflected or diffracted on acoustic insulation bodies provided upright to the vehicle body of a mobile vehicle and being transmitted outside the vehicle body, so as to further reduce the noise reaching the observer of the noise (or local residents).
The object of the present invention is to provide an acoustic insulation device for a mobile vehicle for blocking the noise that is reflected or diffracted on the acoustic insulation bodies provided upright to the vehicle body and being transmitted outside the vehicle body, that can fit within the critical range of the vehicle traveling in a conventional railway section, and that can ensure a sufficient insulation distance with the power collector, so that the noise reaching the observer (or local residents) is further reduced.
Solution to Problem
In order to solve the problems mentioned above, the present invention provides an acoustic insulation device for a mobile vehicle having acoustic insulation bodies provided upright on a roof of the vehicle body so as to oppose to a device disposed on the roof on both sides in a width direction of the vehicle body; wherein
the acoustic insulation device acts on a noise generated in, and in the vicinity of, the device and diffracted or reflected on the acoustic insulation body to suppress transmission of the noise to an outer side of the vehicle body.
According to the present invention, when a mobile vehicle travels, the noise generated in a device disposed on the rooftop and in the vicinity thereof when the vehicle travels is diffracted or reflected by the acoustic insulation bodies provided upright to the roof, and then the noise is transmitted to the outside of the vehicle, but since the acoustic insulation bodies act on the diffracted or reflected noise and prevent the noise from being transmitted to the outer side of the vehicle body, noise can be reduced efficiently.
One example of the means for acting on the noise being diffracted or reflected on the acoustic insulation bodies is an acoustic insulation body that is branched from the main acoustic insulation body provided upright on both width-direction sides of the vehicle body with respect to the device on the roof when seen via a projection from the longitudinal direction of the vehicle body. Further, it is possible to provide a secondary acoustic insulation body with respect to the main acoustic insulation body, so that the projection planes of the main acoustic insulation body and the secondary acoustic insulation body partially overlap. Furthermore, it is possible to provide a secondary acoustic insulation body at a position offset in the width direction of the vehicle body with respect to the main acoustic insulation body, so that when a projection is taken in the width direction of the vehicle body, the projection planes partially overlap. In any case, it is requested that that the requested critical range of the vehicle body and the insulation distance from the high voltage section of the power collector are ensured.
Advantageous Effects of Invention
According to the acoustic insulation device for a mobile vehicle of the present invention, the acoustic insulation body branched from the acoustic insulation body provided upright to the roof not only insulates direct noise but also reduces the noise being reflected or diffracted by conventional acoustic insulation bodies and reaching the observer (or local residents). However, since the branched acoustic insulation body itself may cause noise when the vehicle travels, noise is effectively reduced as a whole by disposing the branched acoustic insulation body so that only a portion of the area overlaps with the main acoustic insulation body instead of having all the area thereof overlap. Based on this effect, the present acoustic insulation device can realize the effect of reducing noise that is generated when the vehicle is traveling.
In the case of railway vehicles, the source of noise moves together when the vehicle travels. Therefore, the relative positional relationship between the observer of the noise (or local residents) and the noise source differs constantly. According to the configuration of the acoustic insulation bodies of the present invention, the areas of the acoustic insulation bodies partially overlap with each other, so that the sound blocking property can be achieved even when the sound source is moving.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view of a power collector unit illustrating a first preferred embodiment of an acoustic insulation device for a mobile vehicle.
FIG. 2 is a front view of the power collector unit shown in FIG. 1 .
FIG. 3 is a left side view of the power collector unit shown in FIG. 1 .
FIG. 4 is a right side view of the power collector unit shown in FIG. 1 .
FIG. 5 is a perspective view of a power collector unit illustrating a second preferred embodiment of the acoustic insulation device for a mobile vehicle.
FIG. 6 is a front view of the power collector unit shown in FIG. 5 .
FIG. 7 is a left side view of the power collector unit shown in FIG. 5 .
FIG. 8 is a right side view of the power collector unit shown in FIG. 5 .
FIG. 9 is a perspective view of the power collector unit illustrating a third preferred embodiment of the acoustic insulation device for a mobile vehicle.
FIG. 10 is a front view of the power collector unit shown in FIG. 9 .
FIG. 11 is a left side view of the power collector unit shown in FIG. 9 .
FIG. 12 is a right side view of the power collector unit shown in FIG. 9 .
DESCRIPTION OF EMBODIMENTS
Now, the preferred embodiments of an acoustic insulation device for a mobile vehicle according to the present invention will be described with reference to the drawings.
Embodiment 1
FIGS. 1 through 4 illustrate a first preferred embodiment of an acoustic insulation device for a mobile vehicle according to the present invention, showing the device in perspective view, front view, left side view and right side view, respectively. A mobile vehicle such as a railway vehicle running on tracks has multiple cars connected to realize a train formation, and a power collector, which is one of multiple roof-disposed devices, is disposed on a roof 3 of a specific car out of the multiple cars. As shown in FIGS. 1 through 4 , a power collector is disposed on the roof 3 of a mobile vehicle. The power collector is mainly composed of an insulator 6 fixed to the roof 3 of the vehicle, an underframe 4 supported on the insulator 6 , a collector shoe 5 coming in contact with the overhead wire to collect power from the overhead wire, an arm 7 supporting the shaft of the collector shoe 5 on the upper end, and hinges 8 a and 8 b . The shaft of the arm 7 is supported by the hinge 8 a having a rotation axis that is parallel with a width direction of the vehicle body with respect to the underframe 4 , and the arm can be folded down to store the collector shoe 5 in an inactive position or can be raised up to take a power collecting position, via a joint function realized by a hinge 8 b disposed at an intermediate joint section between the hinge 8 a and the arm 7 .
The insulator 6 is located at a position offset by a predetermined distance toward one side in the width direction of the vehicle body from a center of the width direction, and in correspondence thereto, the center position of the collector shoe 5 in the left and right directions of the body and the location of the arm 7 and hinges 8 a and 8 b are substantially at the center of the width direction of the vehicle body. The collector shoe 5 of the power collector is electrically connected to a different power collector within the same train formation. Therefore, even when the collector shoe 5 is stored in the inactive position, if the different power collector is collecting power, the collector shoe 5 will be charged to a same potential as the collector shoe of the different power collector.
Acoustic insulation bodies are disposed at opposing locations having the power collector intervened therebetween in the width direction of the vehicle body on the roof 3 of the vehicle body. On the left side of the power collector in the direction of travel of the vehicle, the acoustic insulation bodies are composed of a main acoustic insulation body 1 L and an acoustic insulation body 2 L having a smaller height. The acoustic insulation bodies 1 L and 2 L are disposed at the same width-direction position of the vehicle body, and divided continuous wall bodies are disposed in the longitudinal direction of the vehicle body. On the other hand, on the right side of the power collector in the direction of travel of the vehicle, the acoustic insulation bodies are composed of a main acoustic insulation body 1 R having a higher height and an acoustic insulation body 2 R having a lower height. The acoustic insulation bodies 1 R and 2 R are disposed at the same width-direction position of the vehicle body, wherein divided continuous wall bodies are disposed in the longitudinal direction of the vehicle body.
The acoustic insulation body 1 L is disposed at a position opposing to one insulator 6 in the direction of travel of the vehicle, and the acoustic insulation body 1 R is disposed at a position opposing to another insulator 6 . These acoustic insulation bodies 1 L and 1 R are wall bodies formed in a chevron-like shape along the direction of travel of the vehicle, and the heights of the top of the insulation bodies are substantially equivalent to the height of the insulator 6 . The arrangements of the acoustic insulation bodies 1 L and 2 L in the longitudinal direction of the vehicle body are opposite to 1 R and 2 R, so that when seen from the side direction, the acoustic insulation bodies 1 L and 1 R are not overlapped in the direction of travel of the vehicle, in other words, the bodies 1 L and 1 R are disposed so as not to substantially overlap with one another in the direction of travel of the vehicle. When seen from the side, the acoustic insulation body 1 L opposes to the acoustic insulation body 2 R, and the acoustic insulation body 1 R opposes to the acoustic insulation body 2 L.
When the vehicle having the acoustic insulation device arranged as above travels, noise is generated by traveling wind from the shoe body 5 , the insulator 6 and the arm 7 of the power collector being one of the rooftop devices, but the arrangement of the present acoustic insulation bodies enables to insulate such noise. That is, the movement of the vehicle causes the noise source of the power collector to move relatively rearward with respect to the direction of travel of the vehicle, and the alternating arrangement of the acoustic insulation bodies 1 L and 1 R causes the left-side acoustic insulation body 1 L to be displaced rearward in the direction of travel of the vehicle with respect to the acoustic insulation body 1 R disposed on the right side, so that the noise generated from the collector shoe 5 , the power collector insulator 6 and the power collector arm 7 can be blocked efficiently from the observer (or the resident area) on the left side of the direction of travel of the vehicle. Further, by disposing the chevron-shaped acoustic insulation bodies 1 L and 1 R having substantially the same height as the insulator 6 in an alternating manner, the skirts of the chevron-shapes of the acoustic insulation bodies 1 L and 1 R oppose one another with respect to the collector shoe 5 , which takes a non-power collecting position with the arm 7 folded, can ensure sufficient insulating distance without having to form notches. Further, by disposing the acoustic insulation bodies 1 L and 1 R having substantially the same height in an alternating manner, the flow speed will not be increased between the acoustic insulation bodies 1 L and 1 R, so that the increase of aerodynamic noise from the power collector can be prevented, and at the same time, the acoustic insulation bodies 1 L and 1 R can be stored within the critical range of conventional railway vehicles, and further, since the area exposed to the traveling wind becomes relatively small, the aerodynamic noise generated from the acoustic insulation bodies 1 L and 1 R can be minimized. According to the present embodiment, the acoustic insulation effect of a vehicle can be improved by disposing acoustic insulation bodies 1 L and 1 R having simple configurations, the insulating distance can be ensured by using acoustic insulation bodies having a maximum height that falls within the critical range of conventional railway vehicle sections, and the acoustic insulation effect can be achieved.
As shown specifically in FIGS. 1 and 2 , an acoustic insulation body 2 L having a smaller height disposed on one side (left side) in the width direction of the vehicle body on the roof 3 includes an acoustic insulation body 1 LB branched to an outer side in the width direction of the vehicle. According to the arrangement of the acoustic insulation bodies, as shown in FIG. 2 , acoustic insulation bodies 1 L and 2 L (not shown in the drawing because of its positional relationship) are provided upright, and an acoustic insulation body 1 LB is arranged to be branched to the outer side in the width direction of the vehicle body from the acoustic insulation body 2 L. On the other side (right side) in the width direction of the vehicle body, the acoustic insulation body 2 R having a smaller height disposed on the roof 3 includes an acoustic insulation body 1 RB 1 branched to an outer side in the width direction of the vehicle body and an acoustic insulation body 1 RB 2 branched to an inner side in the width direction of the vehicle body. According to the positional relationship of acoustic insulation bodies, as shown in FIG. 2 , acoustic insulation bodies 1 R and 2 R are provided upright, and acoustic insulation bodies 1 RB 1 and 1 RB 2 are branched from the acoustic insulation body 2 R.
FIG. 3 illustrates the present configuration from the left side. The acoustic insulation body disposed on the left side of the power collector is composed of a high acoustic insulation body 1 L, a low acoustic insulation body 2 L, and an acoustic insulation body 1 LB branched from the acoustic insulation body 2 L. The branched acoustic insulation body 1 LB has a portion thereof overlap with the acoustic insulation bodies 1 L and 2 L provided upright, when seen from the side.
FIG. 4 illustrates the present configuration from the right side. The acoustic insulation body disposed on the right side of the power collector is composed of a high acoustic insulation body 1 R, a low acoustic insulation body 2 R, an acoustic insulation body 1 RB 1 branched toward an outer side of the acoustic insulation body 2 R, and an acoustic insulation body 1 RB 2 branched toward the inner side thereof. The branched acoustic insulation bodies 1 RB 1 and 1 RB 2 are disposed so that a portion of the areas overlap with the acoustic insulation bodies 1 R and 2 R provided upright, when seen from the side.
The branched acoustic insulation bodies 1 LB, 1 RB 1 and 1 RB 2 are extended obliquely upward from the upper side of acoustic insulation bodies 2 L and 2 R, respectively. Further, as shown in FIGS. 1 and 3 , the acoustic insulation body 1 LB branched from the acoustic insulation body 2 L is extended along the longitudinal direction of the vehicle body to reach substantially the center of the longitudinal direction of the acoustic insulation body 1 L. Further, as shown in FIGS. 1 and 4 , the acoustic insulation body 1 RB 1 branched from the acoustic insulation body 2 R is extended along the longitudinal direction of the vehicle body to reach substantially the center of the longitudinal direction of the acoustic insulation body 1 R. The aerodynamic noise generated from the power collector and the vicinity thereof can be directly blocked by the acoustic insulation body composed of main acoustic insulation bodies and the acoustic insulation bodies branched therefrom, and even the reflected sound or the diffracted sound can be prevented effectively from being transmitted to the outer side of the vehicle body from the roof 3 , so that the acoustic insulation function can be further enhanced.
The branched acoustic insulation bodies 1 LB, 1 RB 1 and 1 RB 2 are located at positions so as not to interfere with the critical range of the vehicle in the conventional railway sections and the insulation distance of power collectors. Since the power collector is biased toward the left side with respect to the center of the vehicle, as shown in FIG. 2 , a branched acoustic insulation body cannot be disposed on the inner side of the acoustic insulation body 2 R disposed on the left side of the vehicle because of the insulation distance of the power collector, but if there is enough room from the viewpoint of critical range of the vehicle and the insulation distance of the power collector, a branched body can be disposed on the inner side or on both sides in the width direction of the vehicle body. Further, even just one of the branched acoustic insulation bodies 1 RB 1 and 1 RB 2 on the right side insulation body can exert an acoustic insulation effect. Based on actual measurement results, it is recognized that the branched acoustic insulation bodies disposed on the outer side in the width direction of the vehicle body exerts greater sound insulating effects. Further, the illustrated example shows the branched acoustic insulation bodies to be disposed on lower acoustic insulation bodies and extending to the middle of the higher acoustic insulation bodies, but it is possible to have the bodies extend to cover the whole length of the higher acoustic insulation bodies.
The present embodiment having the above-described arrangement enables to provide a simple configuration with a high sound insulating effect, that fits within the critical range of the vehicle in conventional railway sections, and that can ensure sufficient insulation distance between acoustic insulation bodies and the power collector. Furthermore, by only providing acoustic insulation bodies (or acoustic insulation walls), the sound insulating effect of noises generated from the power collector or other devices disposed on the roof can be achieved without increasing the cross-sectional area of the vehicle body. Moreover, considering the critical range of vehicles in conventional railway sections, the height of the acoustic insulation bodies are set lower compared to conventional acoustic insulation bodies. In order to prevent grounding between the acoustic insulation bodies and the horns of the power collector or the insulator, the insulation distance is also ensured between the acoustic insulation bodies and the power collector. Even further, by the branched acoustic insulation bodies, not only the direct noise but also the reflected sound from the opposing acoustic insulation bodies or the diffracted sound that comes around the acoustic insulation bodies can be suppressed from being transmitted to the outer side of the vehicle.
Embodiment 2
The second embodiment of the present invention will be described with reference to FIGS. 5 through 8 . FIGS. 5 through 8 illustrate a second embodiment of an acoustic insulation device for a mobile vehicle, showing the device in perspective view, front view, left side view and right side view, respectively. The members exerting equivalent functions as those of embodiment 1 are denoted by the same reference numbers in embodiment 2, and detailed descriptions thereof are omitted. Also according to the present embodiment 2, acoustic insulation bodies are disposed at opposing locations on a roof 3 of a mobile vehicle with the power collector intervened therebetween. A main acoustic insulation body 1 L and an acoustic insulation body 2 L having a smaller height than 1 L are disposed on top of the roof 3 in a similar formation as embodiment 1 on one side (left side) in the width direction of the vehicle body, but the acoustic insulation body 2 L does not have a branched acoustic insulation body. On the other hand, a main acoustic insulation body 1 R and an acoustic insulation body 2 R having a smaller height than 1 R are disposed on top of the roof 3 in a similar formation as embodiment 1 on the other side (right side) in the width direction of the vehicle body, but the acoustic insulation body 2 R does not have a branched acoustic insulation body.
FIG. 6 illustrates a front view of the present embodiment. As shown in FIG. 6 , the acoustic insulation bodies are disposed on both sides in the width direction of the vehicle body having the power collector intervened therebetween. In the present embodiment, a secondary insulation body 9 is disposed between the acoustic insulation body 1 R and the acoustic insulation body 2 R (not shown in FIG. 6 ) and the power collector on the other side (right side) in the width direction of the vehicle body. The secondary acoustic insulation body 9 has a smaller height than the acoustic insulation body 1 R but has a greater height than the acoustic insulation body 2 R, and is substantially equal to the height of the insulator 6 , wherein the overall shape thereof is a chevron shape, similar to the acoustic insulation body 1 R. Aerodynamic noise is generated if a secondary acoustic insulation body 9 is disposed at a position receiving the influence of the wake flow of acoustic insulation bodies 1 R and 2 R, so that the secondary acoustic insulation body 9 is disposed at a position on the inner side in the width direction of the vehicle body from the acoustic insulation body 2 R and in parallel with the acoustic insulation body 2 R, but with a distance approximately double the thickness (ΔL 1 ) in the width direction of the vehicle body of the acoustic insulation bodies 1 R and 2 R. According to the configuration of the present embodiment, the power collector is placed at a position offset toward the left side with respect to the center of the vehicle, so that the position in which the secondary acoustic insulation body 9 is placed ensures an insulation distance with respect to the high voltage section of the power collector. On the other hand, the secondary acoustic insulation body cannot be disposed between the power collector and the acoustic insulation bodies 1 L and 2 L, based on the relationship between the insulation distance with the collector shoe 5 when the arm 7 is at a folded state.
FIG. 7 illustrates the present configuration from the left side, and FIG. 8 illustrates the present configuration from the right side. Especially, as illustrated in FIG. 8 , the secondary acoustic insulation body 9 is arranged at a displaced position with respect to the acoustic insulation bodies 1 R and 2 R disposed on the right side, and when seen from the side, the secondary acoustic insulation body 9 has a portion of the area thereof overlapped with the acoustic insulation bodies 1 R and 2 R. The area in which the acoustic insulation body 1 R and the secondary acoustic insulation body 9 are overlapped in the longitudinal direction of the vehicle body is shown as ΔL 2 . This area ΔL 2 is the overlapped area at the skirt portion of the chevron shapes of the acoustic insulation body 1 R and the secondary acoustic insulation body 9 , so that the heights thereof are low, and the insulation distance with respect to the collector shoe 5 when the arm 7 is folded can be ensured.
Embodiment 3
The third embodiment of the present invention will be described with reference to FIGS. 9 through 12 . FIGS. 9 through 12 are views illustrating a third embodiment of an acoustic insulation device for a mobile vehicle according to the present invention, showing the device in perspective view, front view, left side view and right side view, respectively. The members exerting equivalent functions as those of embodiment 1 are denoted by the same reference numbers in embodiment 3, and detailed descriptions thereof are omitted. Also according to the present embodiment 3, acoustic insulation bodies are disposed at opposing locations so as to intervene the power collector on a roof 3 of a mobile vehicle. According to embodiment 3, as shown in FIG. 9 , a secondary acoustic insulation body 10 L is disposed on an outer side in the width direction of the vehicle body of the acoustic insulation bodies 1 L and 2 L disposed on the left side, and a secondary acoustic insulation body 10 R is disposed on an outer side in the width direction of the vehicle body of the acoustic insulation bodies 1 R and 2 R on the right side.
FIG. 10 illustrates a front view of the present configuration. As shown in FIG. 10 , the acoustic insulation bodies 1 R and 2 R and the acoustic insulation bodies 1 L and 2 L are disposed on both sides in the width direction of the vehicle body having the power collector intervened therebetween. In the present embodiment, the secondary acoustic insulation body 10 R is disposed on the outer side in the width direction of the vehicle body of the acoustic insulation bodies 1 R and 2 R disposed on the right side of the power collector, and on the other hand, the secondary acoustic insulation body 10 L is disposed on the outer side of the acoustic insulation bodies 1 L and 2 L disposed on the left side of the power collector. The height of the secondary acoustic insulation bodies 10 L and 10 R are respectively at a same level as the height of the acoustic insulation bodies 2 L and 2 R, and the overall shapes thereof are a low chevron shape in which both ends thereof in the longitudinal direction of the vehicle body are shaped similarly as the ends of acoustic insulation bodies 2 L and 2 R. Similar to embodiment 2, aerodynamic noise may occur if the distance between the acoustic insulation bodies and the secondary acoustic insulation bodies is small, so that the secondary acoustic insulation bodies 10 L and 10 R are positioned on the outer side in the width direction of the vehicle body to acoustic insulation bodies 2 L and 2 R and in parallel with the acoustic insulation bodies 2 L and 2 R but with a distance approximately double the thickness of the acoustic insulation bodies 1 R and 2 R in the width direction of the vehicle body. The secondary acoustic insulation bodies 10 L and 10 R are extended in the longitudinal direction of the vehicle body to reach the position corresponding to approximately the center of the acoustic insulation bodies 1 L and 2 L in the longitudinal direction of the vehicle body. Since the secondary acoustic insulation bodies 10 L and 10 R are disposed on the outer side of the acoustic insulation bodies 1 L and 2 L and the acoustic insulation bodies 1 R and 1 R in the width direction of the vehicle body, they must be restricted to a shape to fit within the critical range of a vehicle in conventional railway sections, but they are positioned at insulation distances from the high voltage section of the power collector.
FIG. 11 illustrates the present configuration from the left side, and FIG. 12 illustrates the present configuration from the right side. Especially, as shown in FIG. 11 , with respect to the acoustic insulation bodies 1 L and 2 L on the left side, the secondary acoustic insulation body 10 L is basically positioned within the area blocked by the acoustic insulation bodies 1 L and 2 L when seen from the side, but as shown in FIG. 12 , with respect to the acoustic insulation bodies 1 R and 2 R on the right side, the secondary acoustic insulation body 10 R has a somewhat higher height than the height of the acoustic insulation body 2 R, and it is located to cover the open space formed on the upper area of the skirts of the overlapped acoustic insulation bodies 1 R and 2 R (range ΔL 2 shown in FIG. 8 of embodiment 2) when seen from the side. The secondary acoustic insulation body 10 R contributes to prevent leakage of noise through this space. Since the secondary acoustic insulation body 10 R is disposed on the outer side of the right-side acoustic insulation bodies 1 R and 2 R in the width direction of the vehicle body, insulation distance can be ensured from the collector shoe 5 when the arm 7 of the power collector is folded.
The present invention has been described taking a railway vehicle as an example of the mobile vehicle, but the present invention is not restricted thereto, and it can be applied to vehicles in which noise is generated from a rooftop device such as a power collector when traveling at high speed. Moreover, the secondary acoustic insulation body 9 and the secondary acoustic insulation bodies 10 L and 10 R have been distinguished in the specification, but it is possible to adopt both secondary acoustic insulation bodies as long as various limitations such as space are satisfied.
REFERENCE SIGNS LIST
1 L, 1 R Acoustic insulation body
1 LB, 1 RB 1 , 1 RB 2 Branched acoustic insulation body
2 L, 2 R Acoustic insulation body
3 Roof
4 Underframe
5 Collector shoe
6 Insulator
7 Arm
8 a , 8 b Hinge
9 , 10 L, 10 R Secondary acoustic insulation body
ΔL 2 Overlap area
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Provided is an acoustic insulation device for a mobile vehicle in which sound transmitted to the exterior of the vehicle body is blocked by being reflected or diffracted by acoustic insulation bodies provided upright to the vehicle body; and the amount of noise that an observer or local residents are subjected to is further reduced. Movement of a mobile vehicle generates noise in, and in the vicinity of, a power collector or a similar device provided upright on the roof ( 3 ) of the vehicle. Acoustic insulation bodies ( 1 L), ( 2 L), ( 1 R), ( 2 R) are provided upright on the roof ( 3 ), and block noise travelling directly ahead. The noise is diffracted or reflected by the acoustic insulation bodies ( 1 L), ( 2 L), ( 1 R), ( 2 R), and moves so as to be transmitted to the vehicle exterior. However, a branched, blade-shaped acoustic insulation body ( 1 LB) provided to the acoustic insulation body ( 2 L), or branched acoustic insulation bodies ( 1 RB 1 ), ( 1 RB 2 ) provided to the acoustic insulation body ( 2 R), act on the diffracted or reflected noise to block sound, and therefore makes it possible to provide an acoustic insulation device for a mobile vehicle in which transmission to the outside of the vehicle body is minimized and the resulting noise is reduced.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] None
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] None
REFERENCE TO SEQUENCE LISTING OR PROGRAM LISTING
[0003] None
BACKGROUND OF THE INVENTION
[0004] The present invention applies to drainage systems, sprinkler systems, pool water filtration systems, and other plumbing systems that use pipes to transport fluid. The pipes and components of such plumbing systems are assembled using pipe fittings such as tees and elbows. These fittings allow pipes to be coupled together, redirected, and connected to drains, valves, sprinkler heads and other items for controlling the flow and delivery of fluid. After such a plumbing system is assembled, the replacement of an installed fitting is quite difficult since an installed fitting must be cut out of the system and cannot be directly replaced by a duplicate fitting without some amount of system modification and repair. This problem affects metal plumbing systems that are assembled with threaded fittings, since pipes and fittings cannot be unthreaded from any internal point. The problem also affects plastic plumbing systems that are assembled using a glue or cement that creates a semi-permanent or permanent bond between pipes and pipe fittings. In either case, repair of a defective pipe fitting or other component at a location internal to the plumbing system will require that pipes be cut to remove the installed pipe fitting and subsequently lengthened to allow insertion of a replacement pipe fitting. Often, access to an installed fitting is limited due to nearby pipes or other obstacles, and in the case of buried or hidden pipes, access may require excavation or other material removal.
[0005] The difficulty of repairing installed pipe fittings is well known, and prior art attempts to address this problem include multi-piece fittings or sleeves designed to be assembled around connecting pipes or fittings to form mechanical seals such as disclosed in U.S. Pat. Nos. 3,517,701, 3,771,820, 3,944,260, 4,889,370, and 4,109,944. Other prior art includes multi-piece fittings designed to be heat welded around connecting pipes as disclosed in U.S. Pat. No. 6,237,640. Other prior art includes multi-piece fittings with sliding sleeves or telescoping members such as disclosed in U.S. Pat. Nos. 6,318,761, 5,975,587, 4,858,958, 3,857,588 and 4,035,002. Each of these prior art approaches involve multi-piece assemblies, internal seals, field heat welding, or moving parts. Cost and complexity has precluded their widespread usage. Related prior art addresses failures in the pipe itself, as opposed to defective fittings, such as disclosed in U.S. Pat. Nos. 4,386,796 and 5,443,096.
[0006] The present invention is a new kind of pipe fitting that is specifically designed for repair applications. Although simple in concept, these Repair Pipe Fittings (also called Repair Fittings) minimize the amount of material removal, the number of components, the amount of disassembly and assembly, and the amount of labor that is required to replace an installed pipe fitting that is internal to a plumbing system.
BRIEF SUMMARY OF THE INVENTION
[0007] To remove an installed pipe fitting, all of the pipes connecting to the installed fitting must be cut. Even if these connecting pipes are cut as dose to the edges of the installed fitting as possible, the connecting pipes cannot be bridged by a new pipe fitting identical to the installed fitting because, after cutting out the installed fitting, the connecting pipes are too short to be inserted into a replacement fitting that is identical to the installed fitting. So, using standard fittings, replacement of a defective fitting requires further exposure of all connecting pipes so that they can be lengthened with couplings and pipe stubs so that the replacement fitting may be inserted. On the other hand, a Repair Pipe Fitting is a one-to-one replacement of a standard fitting that has been removed from a plumbing system. The arms (inlets and outlets) of a Repair Pipe Fitting are extended to allow adequate insertion of the pipe that is exposed after a defective fitting has been removed, thereby eliminating the need to extend the connecting pipes with couplings and stubs.
[0008] Replacement of a defective fitting using a Repair Pipe Fitting offers advantages over repair with a standard fitting. Repair pipe fittings reduce the amount of excavation required at the point of repair because connecting pipes do not need to be exposed for the addition of couplings and stubs. Because the connecting pipes do not have couplings added, they remain more flexible and easier to insert into the Repair Fitting. Repair cost is reduced through the use of Repair Pipe Fittings since the connecting pipes do not require extension: Repair Fittings eliminate the time to measure, cut pipe stubs and glue couplings, as well as the cost of the additional couplings and pipe. Repair Pipe Fittings can eliminate significant time and cost in those cases where an entire subsystem would otherwise need to be replaced due to access limitation at the point of failure.
[0009] Repair Pipe Fittings also increase the reliability of the repaired plumbing system. Joints are the most likely failure points in a plumbing system. Joint failures are not always apparent when the system is initially tested: they often manifest themselves as slow leaks after the repair has been completed and the system is in use. When replacement of a plastic pipe fitting is done in a confined space, the probability of a joint failure is increased since it is more difficult to apply cement to the entire pipe circumference, and it takes more time between application of cement and insertion of the pipe into the fitting since movement of connecting pipes is restricted. Moreover, it takes two additional joints to extend a cut pipe: one at each end of the straight coupling. A Repair Pipe Fitting reduces the number of joints in the repair by a factor of three.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0010] FIG. 1 . ¾″ 90° Elbow Glued in Place shows a cracked 90° elbow glued in place. As shown, an approximately 1.0 inch length of each connecting pipe is glued into the elbow.
[0011] FIG. 2 . ¾″ 90° Elbow Repair using Repair Elbow shows a 90° Repair Elbow glued in place. The Repair Elbow extends about 0.8″ beyond the ends of the original elbow allowing adequate insertion of the connecting pipes.
[0012] FIG. 3 . ¾″ 90° Elbow Repair using Standard Fittings shows a prior art repair using pipe stubs and straight couplings to allow a new elbow to be used in place of the old, cracked elbow.
[0013] FIG. 4 . Repair fittings Reduce the Required Access Space for Repair shows two elbow repairs in process to illustrate the reduction in access space required to use a Repair Pipe Fitting. This figure shows couplings and stubs as part of a replacement assembly.
[0014] FIG. 5 . Standard ¾ 90° Elbow—Cross Section shows a dimensioned cross section of a typical standard elbow. Insertion stops are noted in the Figure.
[0015] FIG. 6 . ¾ 90° Repair Elbow—Cross Section shows a dimensioned cross section of a ¾ 90° Repair Elbow. Insertion stops are noted in the Figure.
[0016] FIG. 7 . Standard ¾″ Reducing Tee—Cross Section shows a dimensioned cross section of a typical standard reducing tee.
[0017] FIG. 8 . ¾″ Reducing Repair Tee—Cross Section shows a dimensioned cross section of a ¾″ Reducing Repair Tee.
[0018] FIG. 9 . ¾″ Reducing Repair Tee with Gaskets shows an alternate approach for reconnecting cut pipes without the use of glue. This Repair Pipe Fitting is only usable in lower pressure applications such as non-line side sprinkler systems.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The present invention may be used in the repair of any plumbing system where pipes are glued, threaded or otherwise bonded into fittings. Such systems normally use pipe and fittings manufactured from plastics such as PVC (Poly-Vinyl Chloride) or ABS (Acrylonitrile-Butadiene-Styrene) with fittings manufactured from similar materials. These systems are used for drainage, lawn sprinklers, pool water circulation, and other similar applications. It is common for the fittings (e.g. tees or elbows) that are used to connect pipes, valves, and other components to fail after years of service. These failures include cracking of the fitting body, splitting of seams, stripping of threads, and leaking at joints. Moreover, failure of other system components may require replacement of fittings. When these failures occur, the installed pipe fitting must be cut out of the plumbing system.
[0020] FIG. 1 shows an installed elbow with a crack. FIG. 1 , Note [1] indicates that cuts must be made close to the edge of the installed fitting to allow use of a Repair Pipe Fitting. Removal of an installed pipe fitting also requires removal of the pipe ends that are glued into the fitting. As shown in FIG. 1 , approximately 1 inch of PVC is normally glued into a standard pipe fitting; after this length of pipe is removed, it is impossible to insert a single standard fitting in the location where the defective fitting has been removed. After removal of an installed fitting, the remaining pipe segments are too short to accommodate a new pipe fitting that is the same size as the pipe fitting that was removed.
[0021] FIG. 2 shows the pipes of FIG. 1 with a 90° Repair Elbow glued into the exact place where the defective elbow of FIG. 1 was removed. Note that each arm of the Repair Elbow is longer than the corresponding arm of the defective elbow by an amount sufficient to allow adequate insertion of the pipes that were cut to remove the defective elbow. In FIG. 2 , this additional length is shown as 0.8″, so that the overall length of each arm of the Repair Elbow is 3.0″, while the overall length of each arm on the defective elbow is 2.2″. FIG. 2 , Note [2] shows the insertion stop point for pipes inserted into the Repair Elbow is 2.2″ from the outside of the Repair Elbow, which is the overall size of the standard fitting. It should be understood that the principles illustrated by the 90° Repair Elbow in FIG. 2 apply equally well to 45° elbows, couplings, tees and other types of fittings.
[0022] FIG. 3 illustrates the prior art repair process for the defective elbow of FIG. 1 using standard fittings. Normally, a defective pipe fitting is replaced by an assembly comprising a new fitting with a pipe stub and straight coupling for each of the arms. To replace the defective elbow of FIG. 1 , connecting pipes must be cut back from the installed pipe fitting approximately one-half the width of a straight coupling as indicated by Note [3]. Straight couplings, indicated by Note [4], must be glued onto each of the cut back pipes. Pipe stubs of the approximate length of a straight coupling must be glued into the couplings as indicated by Note [5]. Finally, the standard elbow may be glued onto the pipe stubs as indicated by Note [6]. The final assembly of FIG. 3 comprises an elbow, two straight couplings and two pipe stubs, and the overall length of each arm of the assembly (4.5″) is approximately twice the length of the corresponding arm on the original fitting (2.2″). Note that the Repair Elbow shown in FIG. 2 is significantly smaller than the replacement assembly shown in FIG. 3 .
[0023] Pipe segments are less flexible after the addition of couplings, making insertion of the replacement assembly, or the insertion of the final component, more difficult. As shown in FIG. 4 , the access space required to allow pipe flexing and insertion of a Repair Pipe Fining is reduced from the space that is required to insert a prior art replacement assembly using standard fittings. FIG. 4 shows ¾″ Schedule 40 pipe which cannot be easily bent with less than a 6 foot radius. As shown, the Repair Elbow reduces the required access for repair by approximately 20%, which is often sufficient to eliminate a significant amount of excavation work and movement of nearby obstacles. FIG. 4 shows the replacement assembly as a unit, although the couplings and stubs are usually glued onto the pipes before the replacement fitting. The precise order of assembly of the prior art repair varies depending on the access space and obstructions encountered during the repair.
[0024] A cross section view of a standard ¾″ 90° elbow is shown in FIG. 5 . Overall size is 2.25″ square with accommodation for 0.95″ insertion depth. (There is some variation in the size and insertion depth across manufacturers, but not enough to impact the utility of the present invention.) A cross section of the 90° repair elbow is shown in FIG. 6 . The repair elbow extends 0.75″ beyond the edge of the standard elbow, which allows approximately 0.70″ insertion depth for the cut pipe, assuming 0.05″ of material is removed by the cutting tool when the defective elbow is cut out. Typical standard fittings are designed for insertion depths ranging from 0.70″ on short tees to 1.00″ on standard elbows and tees. A full 0.70″ insertion that is properly primed and cemented will be suitable for pressure-side application.
[0025] FIG. 7 and FIG. 8 show dimensioned cross section views of a standard reducing tee and a Reducing Repair Tee. Reducing tees with threaded ports are commonly used for sprinkler head risers. When a sprinkler head is forcibly broken off, it is possible for the riser to break off inside of the tee or for the tee to crack. The Reducing Repair Tee of FIG. 8 can be used to replace a cracked tee or a tee with stripped or otherwise unusable threads.
[0026] FIG. 9 shows a standard reducing tee, as normally used for sprinkler heads, above a variation of the Repair Tee. The Repair Tee in FIG. 9 uses screw-on caps to compress gaskets against the outside diameter of the inserted pipe. This type of fitting eliminates the glue or cement, and is suitable for non-pressure-side applications such as replacement of sprinkler head tees. As indicated by Note [7], the removal of a standard tee leaves a 2.75″ space in the pipe line, and the Repair Tee with gaskets is designed to bridge this gap. One end of the Repair Tee allows pipe insertion to approximately twice the final insertion depth so that the Repair Tee may be slid onto the connecting pipe in one direction, per Note [8], before being placed over the opposite pipe and slid into its final position as set by the stop indicated by Note [9]. Compression caps and o-ring gaskets are well known prior art; however, the use of these items in a Repair Tee as shown in FIG. 9 depends upon the extension and threading of the arms and proper design of the insertion depth stops as claimed by the present invention. The threaded cap and o-rings are shown in FIG. 9 to clarify the use of the Threaded Repair Tee.
[0027] Although the figures referenced in this patent have shown ¾″ PVC (Poly-Vinyl Chloride) pipe, the benefits of Repair Pipe Fittings are equally applicable to all other pipe sizes and to other material types including, but not limited to, ABS (Acrylonitrile-Butadiene-Styrene), CPVC (Chlorinated Poly-Vinyl Chloride), PE (Polyethylene), steel, iron and other metals. Moreover, the figures disclosed in this patent have shown a limited number of fitting types (90° elbows and reducing tees) for simplicity, yet the same principals apply equally well to 45° elbows, street ELLS, tees, couplings, and any other fitting type that is a potential failure point in a plumbing system. All such variations in pipe and fitting sizes, materials, and fitting types are deemed to be within the scope of the present invention. For example, the reducing tee shown in FIG. 9 is an example of a class of Repair Pipe Fittings that might include 45° elbows, 90° elbows, non-reducing tees, straight couplings and other fittings suitable for replacement of defective fittings in low-pressure systems.
[0028] Material or dimensional modification to increase strength or flexibility of the inlets and outlets is also anticipated. Flexible arms would facilitate repair, and it may prove possible to manufacture Repair Pipe Fittings from material similar to that used for flexible PVC pipe; although this is most likely possible only for non-pressurized portions of the plumbing system. Moreover, it is clearly possible to offer variations in the sizes of Repair Pipe Fittings to accommodate variation in the sizes of standard fittings. It is also possible to provide Repair Pipe Fittings to replace smaller Repair Pipe Fittings. Such modifications are obvious to anyone skilled in the art, and all such variations in dimensions and/or material are deemed to be within the scope of the present invention.
[0029] Alternate methods of sealing a Repair Pipe Fitting to connecting pipes are also anticipated. Just as it is possible to thread the arms of a Repair Fitting to accept caps and compression gaskets, thereby facilitating insertion in low pressure applications without glue, as shown in FIG. 9 , other types of bonding may be facilitated by the inlet and outlet extension of Repair Pipe Fittings. Threaded, heat bonded, welded and all such connection variations that are made possible by the extension of the inlets and outlets on the Repair Pipe Fitting are deemed to be within the scope of the present invention.
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Disclosed is a pipe fitting specifically designed for repair applications called a Repair Pipe Fitting. One or more of the arms (inlets or outlets) of a Repair Pipe Fitting is longer than the corresponding arm on a standard pipe fitting, so that connecting pipes that have been cut to remove a standard pipe fitting do not have to be extended to install a Repair Pipe Fitting. Repair pipe fittings are best suited for use with plastic pipe, where joints are sealed with cement, although Repair Pipe Fittings may also be used with metal pipe, where joints are sealed with welds or threads. Repair pipe fittings may be sealed using the same sealing method as used by the original fittings, such as cement for plastic fittings and pipes. Repair pipe fittings may also be sealed using a non-permanent sealing method such as compression caps and gaskets.
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This is a divisional of application Ser. No. 08/234,775 filed on Apr. 28, 1994 now U.S. Pat. No. 5,454,002.
BACKGROUND
The present invention is directed to a semiconductor laser, and a method for making such, having a high thermal conductivity heat sink component enabling the laser to be operated at higher temperatures.
Long-wavelength semiconductor lasers, which emit tunable infrared radiation in the 3 to 30 micron spectral range, are primarily used in tunable diode laser (TDL) spectroscopy systems. TDL spectroscopy, which involves tuning the laser around the absorption bands of a particular molecule, can readily measure sub parts per billion concentrations of trace gases making it a useful tool for detecting and monitoring gaseous pollutants. New pollution emission standards dictated by the Clean Air Act of 1990 will require the monitoring of thousands of smokestacks and other pollution sources throughout the United States. TDL spectroscopy, with its high resolution capabilities, is ideally suited for such monitoring. Atmospheric chemists are presently designing and building TDL spectrometers to measure trace gas concentrations throughout the Earth's atmosphere (M. Loewenstein, "Diode Laser Harmonic Spectroscopy Applied to In Situ Measurements of Atmospheric Trace Molecules", J. Quant. Spectros. Radiat. Transfer, 1988, 40, p. 249). Moreover, long-wavelength tunable diode lasers can be used in feedback control systems to actually reduce emission of pollutants (J. A. Sell, "Tunable Diode Laser of Carbon Monoxide in Engine Exhaust", SPIE, 1983, 438, p.67). Advances in laser performance may eventually allow extension of this pollution control technology to automobiles thus greatly expanding the market for long-wavelength lasers. TDL spectroscopy has also been used to study sub-monolayer concentrations of adsorbates on substrate surfaces (V. M. Bermudez, R. L. Rubinovitz and J. E. Butler, "Study of Vibrational Modes of Subsurface Oxygen on Al (111) Using Diode Laser Infrared Reflection-Absorption Spectroscopy", J. Vac. Sci. Tech., 1988, A6, p. 717). Due to the non-invasive nature of the laser probe, this technique can provide useful information on catalytic reactions and chemical processes (J. E. Butler, N. Bottka, R. S. Sillman, D. K. Gaskill, "In Situ, Real-Time Diagnostics of OMVPE Using IR-Diode Laser Spectroscopy", J. Crystal Growth, 1986, 77, p. 163).
An important TDL spectroscopy feature is its ability to identify and differentiate among compounds that contain different isotopes of a particular element. TDL spectrometers can therefore be used to monitor the motion of isotope-tagged tracer molecules. For example, pollutants tagged with 13 C could be released in the atmosphere and their motion monitored with airborne TDL spectrometers. This offers the unique advantage of observing chemical reaction pathways.
Another example of isotope tracing is in medical diagnostics. Metabolic pathways can be monitored by measuring the 13 CO 2 / 12 CO 2 ratio in the exhaled breath of a patient who has been administered a substance tagged with the non-radioactive isotope 13 C. The 13 CO 2 production correlates directly with the rate at which the particular substance is metabolized. For example, a simple diabetes test would involve feeding a patient 13 C-labeled sugar and monitoring the 13 CO 2 production rate. Such non-invasive analysis of metabolic pathways can form the basis for a whole new field of health research and patient diagnosis. (U. Lachish, S. Rotter, E. Adler, U. El-Hanany, "Tunable Diode Laser Based Spectroscopic System for Ammonia Detection in Human Respiration", Rev. Sci. Instrum., 1987, 58, p. 923, and R. M. Scheck and D. L. Wall, "Medical Diagnostics with TDLs", Photonics Spectra, January 1991, p. 110).
Although some near-infrared spectrometers based upon III-V semiconductor lasers have been developed (D. E. Cooper and R. U. Martinelli, "Near-Infrared Diode Lasers Monitor Molecular Species", Laser Focus World, November 1992, 133), the most widely used TDL spectrometers are based upon narrow bandgap IV-VI semiconductor (also known as lead salt) lasers. Temperature tuned IV-VI semiconductor lasers operate in the 3 to 30 μm spectral region, where gas molecules have their strongest absorption lines, and continue to exhibit better performance characteristics than lasers made from other narrow bandgap semiconductors such as HgCdTe (R. Zucca, M. Zandian, J. M. Arias, and R. V. Gil, "HgCdTe Double Heterostructure Diode Lasers Grown by Molecular Beam Epitaxy", J. Vac. Sci. Technol., 1992, B 10, p. 1587; A. Ravid and A. Zussman, "Laser Action and Photoluminescence in an Indium-Doped n-type Hg 1-x Cd x Te (x=0.375) Layer Grown by Liquid Phase Epitaxy", J. Appl. Phys., 1993, 73, p. 3979). However, by comparison with research on III-V and II-VI semiconductor materials and devices, research on IV-VI semiconductor materials and devices has lagged. Consequently, techniques that may prove successful in improving the performance of IV-VI semiconductor lasers have yet to be explored.
Maximum operating temperature is presently considered the most important limiting factor for IV-VI semiconductor tunable diode lasers. The highest-known operating temperature for devices operated in continuous wave (cw) mode, which is preferred over pulsed mode for infrared spectroscopy applications, is 203K for a laser emitting in the 3.5 μm range (Z. Feit, D. Kostyk, R. J. Woods, and P. Mak, "Single-Mode Molecular Beam Epitaxy Grown PbEuSeTe/PbTe Buried Heterostructure Diode Lasers for Co 2 High-Resolution Spectroscopy", Appl. Phys. Lett., 1991, 58, p. 343). Longer wavelength devices have even lower maximum operating temperatures. Thus, low operating temperatures necessitate the use of cumbersome liquid nitrogen or liquid helium cooling systems in spectrometers based upon these laser devices. A low laser operating temperature also limits the tuning range of individual devices. If TDL operating temperatures can be increased to above 220 to 230K then thermoelectric cooling (TEC) modules could be used enabling a significant simplification of TDL spectrometer instrumentation. Any increase in maximum operating temperature will also expand TDL tuning range, thus further simplifying TDL spectrometer operation.
Thermal modeling of IV-VI semiconductor lasers (R. Rosman, A. Katzir, P. Norton, K. H. Bachem, and H. Preier, "On the Performance of Selenium Rich Lead-Salt Heterostructure Laser with Remote p-n Junction", IEEE J. Quantum Electronics, 1987, QE-23, p.94) shows that there is a large difference under maximum operating temperature conditions, as much as 60 degrees, between the heat sink temperature and the active region temperature. This thermal gradient is reflected in the maximum operating temperature difference between pulsed and cw operation, observed to be as much as 120 degrees (B. Spanger, U. Schiessl, A. Lambrecht, H. B ottner, and M. Tacke, "Near-Room-Temperature Operation of Pb 1-x Sr x Se Infrared Diode Lasers Using Molecular Beam Epitaxy Techniques", Appl. Phys. Lett., 1988, 53, p. 2582). Improving heat removal from the active region would therefore lead to an increase in the maximum operating temperatures of IV-VI semiconductor lasers. The major factor limiting heat dissipation from the active region is the substrate which is still attached to the laser structure.
A substrate removal procedure has been developed for III-V semiconductor laser fabrication by E. Yablonovitch, E. Kapon, T. J. Gmitter, C. P. Yun, and R. Bhat, in "Double Heterostructure GaAs/AlGaAs Thin Film Diode Lasers on Glass Substrates", IEEE Photonics Tech. Lett., 1989, 1, p. 41. According to this technique, an AlGaAs/GaAs/AlGaAs laser structure is grown upon a GaAs substrate with a 500 Å AlAs selectively etchable release layer interposed between the substrate and laser structure. The laser structure is then supported from above by Apiezon W™ wax ("black wax") while the AlAs layer is etched with dilute HF. This "epitaxial lift-off" (ELO) process, which was developed to enable hybrid device packaging, does not degrade the performance of the laser device. Other examples of methods of epitaxial liftoff are seen in F. Agahi, K. M. Lau, A. Baliga, D. Loeber, and N. Anderson, "Photo-Pumped Strained-Barrier Quantum Well Lasers Fabricated by Epitaxial Liftoff", ISDRS, University of Virginia, Charlottesville, Va. (1993); C. Camperi-Ginestet, M. Hargis, N. Jokerst and M. Allen, "Alignable Epitaxial Liftoff of GaAs Materials with Selective Deposition Using Polyimide Diaphragms", IEEE Transactions Photonic Tech. Lett., Vol. 3, No. 12, pgs. 1123-1126, December 1991; and E. Yablonovitch, E. Kapon, T. J. Gmitter, C. P. Yun and R. Bhat, "Double Heterostructure GaAs/AlGaAs Thin Film Diode Lasers on Glass Substrates, IEEE Photonic Tech. Lett., Vol. 1, No. 2, pgs. 41-42, February 1989.
However, epitaxial-lift off methods using wax are difficult, time-consuming, require extra handling steps and are not readily adaptable to mass production techniques. A method for producing a laser not confined to the limitations of epitaxial lift-off using the wax method and which resulted in the production of a laser operable at higher temperatures would be desirable.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow chart outlining the processing steps of the present invention.
FIG. 2 is a perspective view of a plurality of plates used in the cleaving assembly.
FIG. 3 is a perspective view of a cleaving assembly used in accordance with the present invention.
FIG. 4A is a perspective view of an alternate version of a cleaving assembly, partially assembled.
FIG. 4B is a perspective view of the cleaving assembly of FIG. 4A completely assembled.
FIG. 5A is a perspective view of an epitaxial layer grown upon a substrate.
FIG. 5B is an enlarged detail view of the epitaxial layer of FIG. 5A.
FIG. 6 is a perspective view of a cleaving assembly having a bonding layer.
FIG. 7 is a perspective view of an epitaxial layer-substrate assembly with a bonding layer disposed thereon.
FIG. 8 is a perspective view of an epitaxial layer-substrate assembly bonded to a cleaving assembly.
FIG. 9 is a perspective view of an epitaxial layer cleaving assembly after substrate removal.
FIG. 10 shows a single plate, with a bonded epitaxial layer, detached from the cleaving assembly.
FIG. 11 shows a single laser bar cut from a detached plate.
FIG. 12 shows a perspective view of a laser bar with an insulating layer.
FIG. 13 shows a perspective view of a laser bar mounted upon a metal cold finger.
FIG. 14 shows a perspective view of the semiconductor laser device with a second metal cold finger.
FIG. 15 shows a perspective view of an alternate version of a semiconductor laser with a second metal cold finger.
FIG. 16 shows a perspective view of an epitaxial layer after for proton bombardment for producing a plurality of single mode waveguides.
FIG. 17 shows the epitaxial layer of FIG. 16 with a layer of BaF 2 evaporated thereupon.
FIG. 18 shows the epitaxial layer of FIG. 17 after photoresist removal.
FIG. 19 shows the epitaxial layer of FIG. 18 after application of a layer of bonding metal.
FIG. 20 is a perspective view of a laser bar having a plurality of single mode waveguides.
DESCRIPTION OF THE INVENTION
An objective of the present invention is to provide a laser having increased heat dissipation from the lasing region, thus allowing higher operating temperatures, and thereby optimizing cooling requirements. It is projected that by improving heat removal from the active region of the laser, the IV-VI semiconductor TDL maximum cw operating temperatures can be increased by more than 50K, thereby placing a considerable portion of the TDL operating temperature range within the effective range of thermoelectric cooling devices.
There has been a considerable need for improving heat dissipation from the active region of TDL devices due to the fact that IV-VI semiconductors have extremely low thermal conductivities, (see Table I).
TABLE I______________________________________Thermal conductivities (watt/cm K.) of variousmaterials at 300 K.PbSe PbTe BaF.sub.2 GaAs Silicon Copper CVD Diamond______________________________________0.018 0.023 0.329 0.60 1.412 5.0 >10.0______________________________________
All previous IV-VI semiconductor TDLs have been packaged with relatively thick (˜250 μm) PbTe substrates still attached to the device structure. Since PbTe is 217 times less thermally conductive than copper, heat is effectively removed from only one side of the device (the non-substrate side). By eliminating the substrate entirely and placing a second heat sink within microns of the active region, as is shown in the present invention, heat dissipation is effectively doubled. Thermal modeling results show that maximum TDL operating temperatures increase by more than 60 degrees when this second copper heat sink is used, a realistic value considering the work of R. Rosman, A. Katzir, P. Norton, K. H. Bachem, and H. Preier, "On the Performance of Selenium Rich Lead-Salt Heterostructure Laser with Remote p-n Junction", IEEE J. Quantum Electronics, 1987, QE-23, p.94. Use of the method of TDL fabrication procedure shown herein should increase maximum cw operating temperatures to greater than 260K.
The present invention, therefore, comprises a method for producing a tunable semiconductor diode laser using a IV-VI semiconductor material wherein the growth substrate has been removed (III-V and II-VI semiconductor materials may also be used). The overall process is described briefly in the flow chart shown in FIG. 1. In Step I, a cleaving assembly and a semiconductor epitaxial layer (or layers) which has been grown on an appropriate substrate by methods well known to one of ordinary skill in the art is provided. The exposed surface of the semiconductor epitaxial layer is then bonded to a prepared surface of the cleaving assembly, which is composed of a plurality of connected plates (Step II). The substrate is then removed, leaving only the semiconductor epitaxial layers bonded to the cleaving assembly (Step III). The single plates of the cleaving assembly are separated individually, causing the epitaxial layers to cleave along parallel crystallographic planes such as {100} or {110} planes (Step IV). Individual laser bars are then cut, if necessary, from each plate (Step V). The laser bar is then mounted on a cold head to form a packaged tunable diode laser (Step VI).
More particularly, the present invention comprises a method of producing a semiconductor laser device. The first step comprises providing a semiconductor epitaxial layer grown on a substrate. Next, a cleaving assembly having at least one cleaving portion is provided. The semiconductor epitaxial layer is bonded to the cleaving assembly wherein at least a portion of the semiconductor epitaxial layer is bonded to the cleaving portion or plate of the cleaving means and an adjacent portion of the semiconductor epitaxial layer is bonded to an adjacent portion of the cleaving assembly (which may be an adjacent cleaving portion or plate) which is adjacent the cleaving portion. Following this, the substrate is removed from the semiconductor epitaxial layer. Finally, the cleaving portion or plate is separated from the cleaving assembly wherein the portion of the semiconductor epitaxial layer bonded to said cleaving portion is cleaved from the adjacent portion of the semiconductor epitaxial layer. These steps may be repeated for additional cleaving portions or plates which may comprise the cleaving assembly. These steps form Fabry-Perot laser cavities in the semiconductor epitaxial layer resulting in a semiconductor laser device comprising a heat conductive portion derived from the cleaving portion and a laser portion derived from the epitaxial layer.
In a preferred version of the invention, the method has an initial step of providing a semiconductor assembly having an epitaxial layer grown on a substrate. The epitaxial layer has an upper surface with an epitaxial bonding layer disposed thereon. A cleaving means, more particularly a cleaving jig, comprising a plurality of detachably connected plates is provided. Each plate has an end surface, which end surfaces cooperate to form a cleaving jig bonding surface which has a cleaving jig bonding layer disposed thereon.
In the next step, a cleaving jig-semiconductor assembly is formed by bonding the epitaxial bonding layer of the semiconductor assembly to the bonding layer of the cleaving jig wherein is formed a bonding layer between the cleaving jig bonding surface and the upper surface of the epitaxial layer. Following this, the substrate is removed from the cleaving jig-semiconductor assembly. Finally, a plate is disconnected from the cleaving jig-semiconductor assembly wherein the epitaxial layer bonded to the plate is cleaved from a portion of the epitaxial layer bonded to an adjacent plate. This disconnection step forms a semiconductor laser cavity (Fabry-Perot) device comprising a plate portion which is heat conductive and a semiconductor portion.
This process may be followed by the additional step of cutting the semiconductor laser device into a plurality of laser bars wherein each laser bar comprises a plate portion and a semiconductor portion. Further, in the process, the step of providing a semiconductor assembly may be preceded by the additional step of applying the epitaxial bonding layer to the upper surface of the epitaxial layer. Also, the step of providing a cleaving jig may be preceded by the additional step of applying the cleaving jig bonding layer to the cleaving jig bonding surface. The plates may be further defined as being made from metal or from diamond. Additionally, an isolating layer for electrically isolating the laser bar may be applied to a portion of the plate portion of the laser bar. Finally, the laser bar thus electrically isolated may be disposed upon a cold finger whereby the isolating layer of the laser bar is disposed upon a mounting surface of the cold finger and the semiconductor portion of the laser bar is disposed adjacent a laser facing surface of the cold finger. A second cold finger, which also may be comprised of metal or diamond, may be disposed upon a portion of the laser bar for further enhancing heat dissipation.
The epitaxial layer may be a IV-VI, III-V or II-VI semiconductor. Further, the semiconductor assembly may further comprise a release layer positioned between the epitaxial layer and the substrate. Further, the laser bar may be further defined as having a semiconductor portion tunable within a range of from about 3 to about 30 micrometers. Further, the epitaxial layer of the semiconductor assembly may further comprise at least one single mode waveguide region. The plate of the cleaving jig may be further defined as having a thickness in a range of from about 100 to about 1000 micrometers.
The semiconductor laser assembly produced by the method of the present invention comprises (1) a cold finger having a mounting surface, and (2) a semiconductor laser having (a) a heat conductive portion having an end surface and a mounting surface, and (b) a semiconductor epitaxial layer having a bonding surface and an exposed end surface. In the semiconductor laser, the bonding surface of the epitaxial layer is bonded to the end surface of the heat conductive portion. The semiconductor laser is mounted upon the cold finger by engaging the mounting surface of the semiconductor laser with the mounting surface of the cold finger. The heat conductive portion of the semiconductor laser in one version of the invention is metal. The heat conductive portion of the semiconductor laser in another version of the invention is diamond. Further in a preferred version of the invention, the cold finger is comprised of metal.
The semiconductor laser assembly may further comprise an isolating layer disposed between the mounting surface of the semiconductor laser and the cold finger which serves to electrically isolate the mounting surface of the semiconductor laser from the cold finger. The assembly may further comprise a first electrical lead attached to a portion of the cold finger and a second electrical lead attached to the heat conductive portion of the semiconductor laser. The cold finger may further comprise a laser facing surface adjacent or against which the exposed end surface of the semiconductor epitaxial layer is disposed.
The semiconductor laser assembly may further comprise a second cold finger disposed upon a second contact surface of the heat conductive portion of the semiconductor laser. Portions of the second cold finger which are adjacent the first cold finger are electrically isolated from the first cold finger. This embodiment of the semiconductor laser assembly may further comprise a first electrical lead and a second electrical lead. In such case, each lead is attached to a separately isolated electrically conductive portion of the semiconductor laser assembly. At least one version of the semiconductor laser assembly described above may further comprise an optical pumping means for inducing emission of laser light. Any of the versions of the semiconductor laser device described herein may be installed in a spectrometer equipped to receive such a device.
The cleaving means used in a preferred version of the present invention is a cleaving jig comprising a plurality of metal plates. Each metal plate has a first facing surface, a second facing surface, a first side surface, a second side surface, an upper end surface and a lower end surface. The plurality of plates are positioned against each other such that each plate has at least one facing surface disposed against a facing surface of an adjacent plate. The lower end surfaces of the plurality of plates are all oriented in the same plane. The cleaving jig further comprises a connecting assembly which detachably connects the plurality of adjacently disposed plates into a plate assembly having a first end and a second end and wherein the lower end surfaces of the plates cooperate to form a bonding surface for bondingly connecting a semiconductor epitaxial layer to the plate assembly.
The connecting assembly may further comprise at least a first screw with screw threads and a second screw with screw threads. Each plate further comprises at least a first hole and a second hole through which the first screw and second screw are driven for connecting the plates and forming the plate assembly.
The cleaving jig may further comprise a first end block plate positioned at the first end of the plate assembly and a second end block plate positioned at the second end of the plate assembly. The second end block plate has a pair of holes with screw threads for matingly engaging the screw threads of the first screw and the second screw when the first screw and second screw are inserted through the first holes and second holes of the plates. The cleaving jig may further comprise a metallic bonding layer disposed upon the bonding surface.
A more detailed description of the process of fabricating the apparatus is provided below and in FIGS. 2-20.
Laser Fabrication
Shown in FIGS. 2 and 3 is a plurality of metal plates 10 which comprise subunits of a cleaving jig. Each metal plate 10, or cleaving portion, comprises an upper end 12, a lower end 14, a front surface 16, a rear surface 18, an upper side 20, a lower side 22, a first lateral side 24 and a second lateral side 26. Each plate 10 further has a height 28 which extends from the upper end 12 to the lower end 14, a width 30 which extends from the first lateral side 24 to the second lateral side 26 and a thickness 32 which extends from the front surface 16 to the rear surface 18. Each plate 10 further comprises a first hole 34a extending from the front surface 16 to the rear surface 18 and a second hole 34b in a different position in the plate 10 parallel to the first hole 34a. A first connector 36a and a second connector 36b are inserted through the holes 34a and 34b, respectively, of the plurality of plates 10, thereby forming the plates 10 into a cleaving jig 38. Together the upper sides 20 of the plates 10 of the jig 38 form an upper surface 40 of the jig 38. Each plate 10 is made from a high conductivity metal, preferably an oxygen-free high conductivity copper. As noted above, the plates 10 could be made from high thermal conductivity diamond, therefore, it will be understood that where used herein, the term metal can be substituted for by the word diamond. The thickness 32 of the plate 10 ultimately determines the length of the cavity of the laser. The thickness 32 is generally from about 100 to 1000 micrometers and more preferably from 300 to 1000 micrometers.
Shown in FIGS. 4A and 4B and represented by the general reference numeral 38a is an alternative version of the cleaving jig of the present invention. The jig 38a is the same as the jig 38 except that the plates 10 are sandwiched between a first end block 42a and a second end block 42b. First end block 42a has holes 34a and 34b which are counter bored and second end block 42b has holes 34a and 34b which are threaded for threadly engaging the threads of the connecting screws 36a and 36b. The heads of the connecting screws 36a and 36b can be recessed within the counter bored holes 34a and 34b of the first end block 42a. Shown in FIG. 4B is the completely assembled cleaving jig 38a. The jig 38a can be held in a milling device to allow milling of the edges of the plates to create a flush and uniform assembly of plates 10.
Shown in FIG. 5A is a semiconductor-substrate assembly 46 comprising a semiconductor epitaxial layer 48, which may further comprise a plurality of layers such as layers 48a, 48b and 48c as shown in FIG. 5B and as is well known to one of ordinary skill in the art. The layer 48 has a thickness 50 which preferably is from about 3 to 5 micrometers. The semiconductor-substrate assembly 46 further comprises a substrate 52 which in one version is silicon and which has a thickness 54, and a release layer 56 which in one embodiment is BaF 2 and which is disposed between the epitaxial layer 48 and the substrate 52 and which has a thickness 58. The semiconductor-substrate assembly 46 also has an upper exposed surface 60 which is the outermost layer of the epitaxial layer 48.
Shown in FIG. 6 is a cleaving jig 38 to which a bonding layer 62 has been applied by standard thermal evaporation techniques over the jig surface layer 40. The jig bonding layer 62 has a thickness 64 and an upper surface layer 66. Shown in FIG. 7 is a semiconductor-substrate assembly 46 to which a semiconductor bonding layer 68 has been applied by standard thermal evaporation techniques over the upper surface layer 60. The bonding layer 68 has a thickness 70 and an upper surface layer 72. Shown in FIG. 8 is a jig-semiconductor-substrate assembly 74 comprising a jig assembly 38 which is bonded to a semiconductor-substrate assembly 46 via a jig-semiconductor bonding layer 76 located between the upper surface 42 of the cleaving jig 38 and the upper surface 60 of the semiconductor-substrate 46. The jig 38 and semiconductor substrate assembly 46 are bonded to one another at a temperature of generally greater than about 235° C. The resulting jig-semiconductor bonding layer 76 has a thickness 78.
In the process of the present invention, the bonding layers 66 and 72 will preferably use a gold/tin eutectic bonding medium each having a thickness of about 1/2 micrometer, such as that described in: G. S. Matijasevic, C. C. Lee, C. Y. Lee, "Au-Sn Alloy Phase Diagram and Properties Related to Its Use as a Bonding Medium", Thin Solid Films, 1993, 223, p. 276 which is hereby incorporated herein by reference. Preferably, the thickness 78 of the bonding layer 76 is about one micrometer or less to allow cleavage of the bonding layer 76. It will be understood by one of ordinary skill in the art that the bonding layers 66 and 72 may each be comprised of a plurality of layers of bonding material.
Shown in FIG. 9 is a jig-semiconductor assembly 80 which is obtained when the substrate 52 is removed from the jig-semiconductor substrate assembly 74 by etching away or dissolving the release layer 56 in a manner known to one of ordinary skill in the art. The jig-semiconductor assembly 80 comprises the cleaving jig 38 which is bonded via the bonding layer 76 to the epitaxial layer 48. Also represented in FIG. 9 by dashed lines extending below the cleaving plates are a plurality of cleavage planes 82 which extend substantially perpendicularly through the epitaxial layer 48. After removal of the substrate 52 to form the jig-semiconductor assembly 80, the connectors 36a and 36b are removed, then each plate 10 can be detached from the adjacent plate 10 of the assembly 80 by sliding the plate 10 such that the epitaxial layer 48 is cleaved along {100} or {110} cleavage planes 82 to form a plate-semiconductor assembly 84 represented in FIG. 10. The plate-semiconductor assembly 84 has a height 86 which extends from the exposed lower surface 87 of the epitaxial layer 48, through the bonding layer 76 to the lower side 22 of the plate 10.
Shown in FIGS. 11 and 12 is a laser bar 88 which has been cut from the plate-semiconductor assembly 84 by cutting from the lower side 22 of the plate 10 through the plate 10 through the epitaxial layer 48. The laser bar 88 thus has a plate portion or metal finger portion 89 and a semiconductor laser portion 90. The semiconductor laser portion 90 may be comprised of a plurality of layers shown in FIGS. 10-11 as layers 90a, 90b and 90c. It will be understood by one of ordinary skill in the art that the semiconductor laser portion 90 may comprise more or fewer than the three layers 90a, 90b and 90c shown in FIGS. 11 and 12. The laser bar 88 has a cavity length 91 which is preferably in the range of from 100 to 1000 micrometers, more preferably between 300 and 1000 micrometers, a height 92 which may be from about 500 micrometers to as much as 1 centimeter, and an overall length 93. The metal finger portion 89 of the laser bar 88 has an end 94 with an end surface 96. The semiconductor laser portion 90 has an end 98. The laser bar 88 has a front surface 100, a rear surface (not shown), a first side surface 102 and a second side surface 104. In FIG. 12, the laser bar 88 is shown with an isolating layer 106 which has been disposed upon a portion thereof, preferably the first side surface 102. The isolating layer 106 isolates the metal finger portion 89 of the laser bar 88 enabling it to serve as an electrode. The isolating layer 106 could be either a thin plate of thermally conductive sapphire or a wafer of chemically vapor deposited (CVD) diamond or other suitable electrically isolating material. CVD diamond wafers are commercially available, for example, from Harris Diamond Corp., Arlington, N.J. or Norton Diamond Film, Northboro, Mass. (see G. Lu and E. F. Borchelt, "CVD Diamond Boosts Performance of Laser Diodes", Photonics Spectra, September 1993, p. 88). With thermal conductivities more than twice that of copper, CVD diamond will assist in the dissipation of heat from the laser active region.
After the isolating layer 106 has been applied, the laser bar 88 is disposed upon a metallic electrode 108 of a metal cold finger 110 as shown in FIG. 13 in a manner well known in the art resulting in a laser assembly generally referred to by reference numeral 112. The laser assembly 112 may have electrical leads 114 and 116 connected to the metal finger 89 and to the metal electrode 108. Moreover, the metal electrode 108 and the cold finger 110 may be integral to each other forming in essence a unitary electrode. The laser assembly 112 can then be installed in an instrument for use in spectroscopic applications known generally in the art such as those cited above and in the article by R. S. Eng, J. F. Butler and K. J. Linden; "Tunable Diode Laser Spectroscopy: An Invited Review", Optical Engineering, Vol. 19, No. 6, pgs. 945-960, 1980. For example, the laser assembly 112 could be installed in a tunable diode laser system for high resolution spectroscopy (FIG. 1.6 in Eng et al. cited above).
An additional metal heat sink may be disposed over the second side surface 104 to further increase the heat dissipation from the lasing region as further explained below.
Shown in FIG. 14, and referred to generally by the reference numeral 120 is a dual heat sink laser assembly. The dual heat sink laser assembly 120 is exactly the same as the laser-cold finger assembly 112 described above except that it further comprises a second isolating layer 122, a second metallic electrode 124, and a second cold finger 126. The second isolating layer 122 is disposed between the semiconductor laser portion 90 and the first metallic electrode 108. The second metallic electrode 124 is disposed upon a portion of the laser bar 88 to form an electrical contact therewith. The second cold finger 126 is in turn disposed upon the second metallic electrode 124 generally as indicated in FIG. 14. The arrow 128 generally indicates the direction of light emission from the laser diode 120.
Shown in FIG. 15 and referred to generally by the reference numeral 120a is an alternate version of a dual heat sink laser assembly. The laser assembly 120a is exactly the same as the laser assembly 120 except for the orientation of the isolating layers which separate the two electrode portions of the laser assembly. In this version, a laser bar 88a having a semiconductor portion 90a has an isolating layer 106a disposed upon an upper surface thereof. The lower surface of the laser bar 88a is contactingly disposed upon a mounting surface of a metallic electrode 108a which is itself mounted upon a metal cold finger 110a. A second isolating layer 122a separates the metallic electrode 108a from a second metallic electrode 124a which is disposed upon the laser bar 88a in a position such that the isolating layer 106a separates the metallic portion of the laser bar 88a from the second metallic electrode 124a. A second metal cold finger 126a may be disposed upon the second metallic electrode 124a.
It will be understood by one of ordinary skill in the art that the cold fingers, metallic electrodes, and isolating layers may be arranged in a variety of configurations which differ from the configuration shown in FIGS. 14 and 15. It will be understood by one of ordinary skill in the art that the metallic electrodes 108 and 108a and the cold fingers 110 and 110a may comprise a single functional unit such that each cold finger 110 or 110a itself may comprise the electrode 108 or 108a, respectively. This is also true for the second cold fingers 126 and 126a and second metallic electrodes 124 and 124a. In such cases the terms metallic electrode and cold finger may be used interchangeably and either may be generally referred to as a "metal electrode".
The semiconductor diode lasers may also be driven by optical pumping in a manner well known to one of ordinary skill in the art. Optically pumped devices have the advantage of needing neither p-n junctions nor electrical contacts. Since electric current is not driven through the device, lasing can be achieved at higher operating temperatures. High power near-infrared III-V semiconductor diode lasers or even LEDs may be used as pump sources for IV-VI semiconductor lasers, for example.
Semiconductor/Substrate Assemblies
By way of further explanation, an example of a IV-VI semiconductor/substrate assembly 46 is the Pb 1-x Sn x Se 1-y Te y system. This pseudobinary alloy can be used as the active region in lasers designed to operate in the 6 to 30 μm spectral range. Most IV-VI semiconductor DH and BH lasers have been fabricated with PbSe 1-y Te y ternary and Pb 1-x Sn x Se 1-y Te y quaternary layers lattice matched with Pb 1-x Sn x Te substrates (Y. Horikoshi, M. Kawashima, and H. Saito, "PbSnSeTe-PbSeTe Lattice-Matched Double Heterostructure Lasers", Japanese J. Appl. Phys., 1982, 21, p. 77; and A. Shahar and A. Zussman, "PbSnTe-PbTeSe Lattice Matched Single Heterostructure Diode Lasers Grown by LPE on a (111) Oriented PbSnTe Substrates", Infrared Physics., 1987, 27, p. 45).
Work has also been done with Pb 1-x Sn x Se 1-y Te y quaternary layers lattice matched with PbSe substrates (P. J. McCann, J. Fuchs, Z Feit, and C. G. Fonstad, "Phase Equilibria and Liquid Phase Epitaxy Growth of PbSnSeTe Lattice Matched to PbSe", J. Appl. Phys., 1987, 62, p. 2994; and H. Preier, A. Feit, J. Fuchs, D. Kostyk, W. Jalenak, and J. Sproul, "Status of Lead Salt Laser Development at Spectra-Physics", presented at the Second International Symposium on Monitoring of Gaseous Pollutants by Tunable Diode Lasers, November, 1988).
Such epitaxial structures, when grown on Pb 1-x Sn x Te or PbSe substrates, are usually fabricated into laser devices by cleaving the entire layer/substrate structure along {100} planes to form Fabry-Perot cavities.
Another example of a semiconductor substrate assembly 46 consists of three LPE layers grown on a BaF 2 substrate. An example of a method of growing an epitaxial layer on BaF 2 is provided in U.S. Ser. No. 07/367,459, entitled "A Chemical Method for the Modification of Substrate Surface to Accomplish Heteroepitaxial Crystal Growth", by P. J. McCann and C. G. Fonstad, filed Jun. 16, 1989, and which is hereby incorporated herein by reference.
Cleavage of the entire epitaxial layer/substrate structure along {100} planes would be difficult with a IV-VI semiconductor/BaF 2 structure since BaF 2 tends to cleave along {111} planes. In the present invention, this problem is solved for BaF 2 substrate-grown epitaxial layers by removing the BaF 2 substrate before cleaving the laser structure. Removing the BaF 2 substrate without chemically attacking the laser structure is possible since BaF 2 is soluble in water while IV-VI semiconductor epitaxial layers are not. An acid solution, preferably a 1:3 HCl:H 2 O solution, which dissolves BaF 2 30 times faster than water alone, could also be used to accelerate substrate removal. Besides having a compatible crystal structure and lattice matching capabilities, BaF 2 is an attractive substrate material for IV-VI semiconductor epitaxy and device development because its thermal expansion coefficient is nearly the same as that of the IV-VI semiconductors. Although BaF 2 substrates have been used for IV-VI semiconductor vapor phase epitaxy since 1970 [19] (H. Holloway and E. M. Logothesis, "Epitaxial Growth of Lead Tin Telluride", J. Appl. Phys., 1970, 41, p. 3543), LPE growth of IV-VI semiconductors on BaF 2 substrates has only recently been accomplished.
Heat dissipation could be also be enhanced by placing a thermoelectric cooler near the device in a manner well known in the art. The thermal properties of such a device are considered optimal for enabling high temperature TDL operation. Thermoelectric coolers are commercially available, for example, the "Frigichip" is available from Melcor, Inc., Trenton, N.J. Another type of TEC is available from Marlow Industries, Inc., Dallas, Tex.
The fabrication procedure outlined in FIGS. 2-15 yields broad area lasers, but can be modified to yield single mode lasers, desired for most infrared spectroscopy applications.
FIGS. 16-20 show the production of a semiconductor laser device having an array of waveguides for high power single-mode lasers. FIG. 16 shows a IV-VI semiconductor epitaxial layer 130 bonded via a BaF 2 buffer layer 132 to a substrate (e.g., silicon) 134. An array of photoresist material 136 is disposed upon the upper exposed surface of the epitaxial layers 130. The epitaxial-substrate-photoresist assembly 138 is subjected to a treatment such as proton bombardment which induces in the epitaxial layers regions 140 each having lower indexes of refraction than the unaffected portions of the epitaxial layer 130. Areas of the epitaxial layer 130 protected from proton bombardment by the photoresist material 136 serve as the single-mode waveguide regions 142 of the laser in a manner well known to one of ordinary skill in the art.
FIG. 17 shows an epitaxial-substrate-photoresist assembly 138 upon which a layer 144 of BaF 2 has been evaporated. The BaF 2 is applied to the assembly 138 to cover the lower index of refraction regions 140, as indicated in FIG. 18 wherein is shown an epitaxial-substrate assembly 146 after the photoresist material 136 has been removed. Shown in FIG. 19 is an epitaxial-substrate assembly 146 upon which a bonding layer 148 has been applied. The bonding layer 148 may be exactly the same as the bonding layer 68 described above in FIG. 7.
The epitaxial layer-substrate assembly 146 having the bonding layer 148 is then ready to be bonded to a cleaving jig for producing a semiconductor laser in a manner exactly as described above in the steps corresponding to FIGS. 8-13.
The layers 144 which remain on the epitaxial substrate assembly 146 shown in FIG. 17 can be protected from dissolution during the substrate removal step by bordering the exposed BaF 2 regions with a layer of photoresist material (not shown) such that the BaF 2 stripes do not extend all the way to the edge of the epitaxial layer.
Shown in FIG. 20 is a laser bar 150 comprising a metal finger portion 152 and a single-mode waveguide semiconductor laser portion 154. The laser bar 150 can then be used in exactly the same way as the laser bar 88 described above.
Laser fabrication from molecular beam epitaxy (MBE)-grown material on silicon substrates can be accomplished using the same epitaxial layer lift-off procedures that have been developed for III-V laser fabrication. Instead of AlAs, though, the BaF 2 buffer layer will function as the release layer. After eliminating the silicon substrate, the same procedure as outlined in above FIGS. 8-12 can then be used to fabricate laser devices. Since there is no thick PbTe substrate, such devices will exhibit the same superior active region heat dissipation as LPE-grown lasers fabricated using the BaF 2 substrate removal technique. Because MBE technology can produce larger bandgap Pb 1-x Eu x Se 1-y Te y alloys and has greater growth flexibility than LPE it offers the best promise for fabrication of TDLs that operate near room temperature. MBE growth combined with focused ion beam etching, through the use of a portable load-lock vacuum chamber, will also allow the fabrication of advanced laser devices such as high power buried heterostructure arrays.
Each of the patents, pending patent applications, and publications cited herein is hereby incorporated herein by reference.
Changes may be made in the construction and the operation of the various components, elements and assemblies described herein or in the steps or the sequence of steps of the methods described herein without departing from the spirit and scope of the invention as defined in the following claims.
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A semiconductor laser device, and method for making such, having higher operating temperatures than previously available. A semiconductor epitaxial layer is bonding to a cleaving assembly which allows the epitaxial layer to be manipulated without use of traditional substrate forms. The resulting semiconductor laser is bonded to a metal portion which serves as a heat sink for dissipating heat from the active lasing region. The resulting semiconductor lasers can be cooled by thermoelectric cooling modules, thus eliminating the necessity of using more bulky cryogenic systems.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thermoplastic fluorine-containing copolymer having flexibility.
2. Discussion of Background
A thermoplastic fluorine-containing copolymer having flexibility and excellent moldability is desired in the field of tubes, sealing materials, films or composite materials thereof. A copolymer of tetrafluoroethylene (hereinafter referred to as TFE) and propylene, which contains at most 60 mol % of polymer units based on TFE, is known as an elastomer.
A three-component copolymer comprising TFE, polypropylene and vinylidene fluoride (hereinafter referred to as VDF) is known as an elastomer.
Further, a copolymer of a fluorinated comonomer of the formula (2) or (3) given hereinafter with TFE or VDE is known as an elastomer.
For example, JP-A-50-50488 discloses a three-component copolymer comprising from 50 to 65 mol % of polymer units based on TFE, from 20 to 45 mol % of polymer units based on propylene and from 5 to 26 mol % of polymer units based on VDF.
JP-A-52-44895 discloses a three-component copolymer comprising from 5 to 50 mol % of polymer units based on TFE, from 5 to 40 mol % of polymer units based on propylene and from 30 to 90 mol % of polymer units based on VDF.
Further, JP-A-52-45685 discloses a three-component copolymer comprising from 25 to 50 mol % of polymer units based on TFE, from 25 to 45 mol % of polymer units based on propylene and from 10 to 30 mol % of polymer units based on VDF.
JP-A-58-71906 discloses a copolymer comprising from 50 to 88 mol % of polymer units based on a fluoroolefin such as TFE or VDF and from 12 to 50 mol % of polymer units based on the comonomer of the formula (3) as defined in the present invention.
Further, JP-A-1-22908 discloses a three-component copolymer comprising from 30 to 80 mol % of polymer units based on TFE, from 5 to 60 mol % of polymer units based on the copolymer of the formula (2) as defined in the present invention, and from 3 to 50 mol % of polymer units based on the comonomer of the formula (3) as defined in the present invention. Such a copolymer is described to be a resilient copolymer having excellent low temperature characteristics.
These copolymers are excellent in flexibility. However, their molded products are elastomeric and, as such, can not practically be used unless they are vulcanized.
On the other hand, a two-component copolymer comprising TFE and VDF is known to be a thermoplastic resin having a melting point of from 150° to 300° C., but it does not have flexibility (Polymer Science USSR A18, No. 12, p2691-2699).
Accordingly, it is conceivable that by increasing the content of polymer units based on TFE and decreasing the content of polymer units based on propylene in a three-component copolymer comprising TFE, propylene and VDF, it may be possible to obtain a copolymer having a thermoplastic nature while maintaining flexibility.
In fact, a copolymer comprising from 40 to 80 mol % of polymer units based on TFE, from 5 to 25 mol % of polymer units based on propylene and from 10 to 55 mol % of polymer units based on VDF, has been confirmed to be a thermoplastic fluorine resin which has flexibility and which has a melting point of from about 130° to about 200° C.
A thermoplastic resin is usually required to have a low melt viscosity for extrusion. However, with the above three-component copolymer, it has been found that if it has a low melt viscosity, the mechanical properties, particularly the tensile strength and the tensile elongation at a high temperature, deteriorate.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a novel thermoplastic fluorine-containing copolymer excellent in high temperature mechanical properties and flexibility.
The present inventors have conducted various studies to solve the above problems and as a result, have found that a fluorine-containing copolymer having polymer units based on a fluorinated comonomer as described hereinafter incorporated to a thermoplastic fluorine resin system comprising polymer units based on TFE, propylene and VDF, is a thermoplastic resin having adequate mechanical properties, particularly excellent high temperature mechanical properties, and desired flexibility. The present invention has been accomplished on the basis of this discovery. It, is believed that with the fluorine-containing copolymer having a fluorinated comonomer having a relatively large side chain introduced, the crystallinity has decreased, and entanglement of molecular chains to one another has increased, whereby high temperature mechanical properties have been improved.
That is, the present invention provides a fluorine-containing copolymer comprising:
(a) from 0.05 to 20 mol % of polymer units based on at least one fluorinated comonomer selected from the group consisting of fluorinated comonomers of the following formulae (1), (2) and (3):
X--R.sup.f --CY═CH.sub.2 (1)
X--R.sup.f --O--CF═CF.sub.2 (2)
CF.sub.3 --(CF.sub.2).sub.n --(O--CF(CF.sub.3)--CF.sub.2).sub.m --O--CF═CF.sub.2 (3)
wherein Y is a fluorine atom or a hydrogen atom, R f is a C 2-12 bivalent fluorinated organic group, X is a fluorine atom, a chlorine atom or a hydrogen atom, n is an integer of from 0 to 3, and m is an integer of from 1 to 4,
(b) from 30 to 85 mol % of polymer units based on TFE,
(c) from 1 to 30 mol % of polymer units based on propylene, and
(d) from 5 to 68.5 mol % of polymer units based on VDF.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The content of polymer units based on TFE in the fluorine-containing copolymer of the present invention is from 30 to 85 mol %. If TFE is less than this range, the decomposition temperature tends to be low, and the moldability tends to be impaired. On the other hand, if the content of polymer units based on TFE exceeds the above range, the polymer units based on TFE or the polymer units based on TFE-VDF tend to crystallize, whereby flexibility will be lost.
The content of polymer units based on propylene is from 1 to 30 mol %. If propylene is less than this range, the flexibility tends to be low, and if it exceeds this range, the copolymer tends to be elastomeric.
The content of polymer units based on VDF is from 5 to 68.5 mol %. The content of the fluorinated comonomer is from 0.05 to 20 mol %. If it is less than this range, the mechanical properties tend to be poor, and if it exceeds this range, the polymerization rate tends to be slow, whereby the productivity will be poor.
The fluorine-containing copolymer preferably has a volumetric flow rate within a range of from 1 to 10 (mm 3 /sec), as an index for the molecular weight. The volumetric flow rate is the volume of a molten sample extruded per unit time (mm 3 /sec) from a nozzle having a diameter of 1 mm and a length of 2 mm under a load of 7 kg at 200° C.
A preferred construction of the fluorine-containing copolymer of the present invention comprises:
(a) from 0.1 to 15 mol % of polymer units based on the fluorinated comonomer,
(b) from 40 to 75 mol % of polymer units based on TFE,
(c) from 5 to 25 mol % of polymer units based on propylene, and
(d) from 10 to 54.5 mol % of polymer units based on VDF.
As the fluorinated comonomer, one member selected from the group consisting of fluorinated comonomers of the formulae (1), (2) and (3), may be used, or two or more of them may be used in combination.
In the bivalent fluorinated organic group for R f in the formula (1) or (2), the number of substituted fluorine atoms may be at least 1. A completely fluorinated bivalent organic group is particularly preferred. R f is preferably a bivalent fluorinated organic group wherein the chain is constituted by carbon atoms only, or carbon and oxygen atoms.
Specifically, R f may, for example, be a perfluoroalkylene group or a perfluoroalkylene group containing an ether bond. The number of carbon atoms constituting the chain for R f is from 2 to 12, preferably from 2 to 10. R f is preferably of a straight chain structure, but may be of a branched structure. In the case of a branched structure, the branched moiety is preferably a short chain having from 1 to 3 carbon atoms.
As the fluorinated comonomer, a (perfluoroalkyl)ethylene such as (perfluorobutyl)ethylene, (perfluorohexyl)ethylene or (perfluorooctyl)ethylene, a perfluoro(alkyl vinyl ether) such as perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether) or perfluoro(propyl vinyl ether), or a compound of the formula (3) wherein n is 1 or 2, and m is 1 or 2, is preferably used.
When one fluorinated comonomer is used, a four component copolymer thereof with TFE, propylene and VDF will be obtained. When two or more fluorinated comonomers are used, it is believed that such fluorinated comonomers are mutually copolymerized to form a five-component copolymer or a copolymer having a higher multi-component structure.
Further, in addition to the above fluorinated comonomers, other copolymerizable components, such as ethylene, isobutylene, acrylic acid and its esters, metacrylic acid and its esters, chlorotrifluoroethylene, alkyl vinyl ethers such as ethyl vinyl ether and butyl vinyl ether, and vinyl esters such as vinyl acetate and vinyl benzoate, may be copolymerized. The content of polymer units based on these other copolymerizable monomers in the fluorine-containing copolymer is preferably not higher than 10 mol % in order to maintain the excellent properties of the fluorine-containing copolymer.
A particularly preferred construction of the fluorine-containing copolymer of the present invention comprises from 0.2 to 5 mol % of polymer units based on the fluorinated comonomer, from 45 to 75 mol % of polymer units based on TFE, from 8 to 20 mol % of polymer units based on propylene, from 10 to 40 mol % of polymer units based on VDF, and from 0 to 5 mol % of polymer units based on copolymerizable components other than the fluorinated comonomer.
As the polymerization method for preparing the fluorine-containing copolymer, any one of emulsion polymerization, suspension polymerization and solution polymerization may be employed. For example, the solution polymerization may be conducted in a fluorine-type solvent such as hydrofluorocarbon or hydrochlorofluorocarbon or in an alcohol type solvent such as tertiary butanol at a temperature of from -40° C. to +150° C. under a relatively low reaction pressure such as from 1 to 50 kg/cm 2 .
The suspension polymerization or emulsion polymerization can be carried out in an aqueous medium. For example, the emulsion polymerization can be conducted at a temperature of from 50° to 100° C. under a pressure of from 5 to 200 kg/cm 2 using a surfactant such as ammonium perfluorooctanoate or sodium lauryl sulfate, a polymerization initiator such as a peroxide, an azo compound or a persulfate, and optionally, a pH controlling agent such as phosphoric acid-phosphate or oxalic acid-oxalate, and a molecular weight controlling agent such as methanol, secondary butanol or pentane. Otherwise, by using a redox type initiator, such as ammonium persulfate, potassium persulfate, a combination of sodium persulfate and a sulfite or thiosulfate, or such a sulfite or thiosulfate and a salt of copper or iron, emulsion polymerization can be carried out at a low temperature of from -20° C. to +50° C.
In the emulsion polymerization, after completion of the reaction, freezing or coagulation by an addition of an electrolyte is carried out, followed by centrifugal separation or filtration to separate a latex of the fluorine-containing copolymer.
The fluorine-containing copolymer of the present invention can be used for various molded products or as a material for lining or coating electric wires. Especially, by virtue of its high flexibility, covered wires or tubes may be applied to complicated wirings or pipings, or to a place where vigorous movements are involved. Further, it has transparency, so that it is useful in the form of a film, for example, as a film for agricultural use excellent in weather resistance or as a cover for a solar cell, or as an interlayer for laminated glass utilizing its flame retardancy.
Now, the present invention will be described in further detail with reference to Examples. However, it should be understood that the present invention is by no means restricted to such specific Examples.
EXAMPLE 1
To a deaerated stainless steel autoclave having an internal capacity of 1 l and equipped with a stirrer, 635 g of deionized water, 5 g of ammonium perfluorooctanoate, 14.9 g of TFE, 1.4 g of propylene, 9.7 g of VDF and 1.2 g of (perfluorobutyl)ethylene were charged, and the temperature was raised to 80° C. Then, 5 ml of a 30% ammonium persulfate aqueous solution was injected to initiate polymerization. To supplement the pressure which decreased as the reaction progressed, a gas mixture comprising TFE/propylene/VDF in a molar ratio of 58/10/32, was introduced, and the reaction was continued under a pressure of 18.3 kg/cm 2 G.
(Perfluorobutyl)ethylene was added in an amount of 0.1 ml per 3 g of the gas mixture, and the reaction was continued for 8 hours.
After completion of the reaction, the monomers in the reactor were purged to obtain 840 g of a latex. Sulfuric acid was dropwise added to this latex for coagulation, followed by washing and drying to obtain 194 g of copolymer a. With respect to copolymer a, the composition (mol ratio) was analyzed by 19 FNMR and 1 HNMR, the melting point (°C.) was measured by DSC, and the volumetric flow rate (mm 3 /sec) as an index for the molecular weight, was measured. The results are shown in Table 1.
Further, the tensile modulus of elasticity (MPa), the tensile strength (kg/cm 2 ) at 25° C. and 100° C. and the tensile elongation (%) of the compression molded product of copolymer a are shown in Table 1.
EXAMPLE 2
To a deaerated stainless steel autoclave having an internal capacity of 1 l and equipped with a stirrer, 615 g of deionized water, 5 g of ammonium perfluorooctanoate, 2.48 g of ammonium oxalate hydrate, 0.82 g of oxalic acid dihydrate, 20 g of TFE, 2 g of propylene, 13 g of VDF and 0.77 g of (perfluorobutyl)ethylene were charged, and the temperature was raised to 50° C. Then, 12 ml of a 3.8% potassium permanganate aqueous solution was injected to initiate polymerization. To supplement the pressure which decreased as the reaction progressed, a gas mixture comprising TFE/propylene/VDF in a molar ratio of 58/10/32, was introduced, and the reaction was continued under a pressure of 17.8 kg/cm 2 G.
(Perfluorobutyl)ethylene was added in an amount of 0.1 ml per 5 g of the gas mixture.
The aqueous potassium permanganate solution was intermittently charged so that the polymerization rate became substantially constant. It was charged in a total amount of 61 ml. After 10.5 hours, the monomers in the reactor were purged to obtain 830 g of a latex. Sulfuric acid was dropwise added to this latex for coagulation, followed by washing and drying to obtain 168 g of copolymer b. The physical properties and mechanical properties of copolymer b were measured in the same manner as in Example 1, and the results are shown in Table 1.
EXAMPLE 3
To a deaerated stainless steel autoclave having an internal capacity of 1 l and equipped with a stirrer, 610 g of deionized water, 3.6 g of ammonium perfluorooctanoate, 14.8 g of disodium hydrogenphosphate 12 hydrate, 1.59 g of sodium hydroxide, 3 g of ammonium persulfate, 0.11 g of iron sulfate, 0.10 g of ethylene diamine tetracetate and 1.8 g of 2-butanol were charged. Then, 22.6 g of TFE, 3.5 g of propylene, 16.0 g of VDF and 1.3 g of (perfluorooctyl)ethylene were charged, and the temperature was maintained at 25° C. Then, 2 ml of a solution containing 1.76 g of sodium hydroxide and 0.29 g of Rongalite per 10 ml of water, was injected to initiate polymerization.
To supplement the pressure which decreased as the reaction progressed, a gas mixture comprising TFE/propylene/VDF in a molar ratio of 53/10/37, was introduced, and the reaction was continued under a pressure of 20.3 kg/cm 2 G. (Perfluorooctyl)ethylene was added in an amount of 0.1 ml per 5 g of the gas mixture, and the reaction was continued for 11 hours. After completion of the reaction, the monomers in the reactor were purged to obtain 827 g of a latex. Sulfuric acid was dropwise added to this latex for coagulation, followed by washing and drying to obtain 187 g of copolymer c. The physical properties and mechanical properties of copolymer c were measured in the same manner as in Example 1, and the results are shown in Table 1.
EXAMPLE 4
To a deaerated stainless steel autoclave having an internal capacity of 1 l and equipped with a stirrer, 635 g of deionized water, 2 g of ammonium perfluorooctanoate, 23.2 g of TFE, 0.9 g of propylene, 6.9 g of VDF and 10.7 g (10.0 mol %) of perfluoro(propyl vinyl ether) were charged, and the temperature was raised to 70° C. Then, 6 ml of a 30% ammonium persulfate aqueous solution was injected to initiate polymerization. To supplement the pressure which decreased as the reaction progressed, a gas mixture comprising TFE/propylene/VDF in a molar ratio of 65/15/20, was introduced, and the reaction was continued under a pressure of 16.2 kg/cm 2 G. After 9.5 hours, the monomers in the reactor were purged to obtain 824 g of a latex. Sulfuric acid was dropwise added to this latex for coagulation, followed by washing and drying to obtain 176 g of copolymer d. The physical properties and mechanical properties of copolymer c were measured in the same manner as in Example 1, and the results are shown in Table 1.
EXAMPLE 5
To a deaerated stainless steel autoclave having an internal capacity of 20 l and equipped with a stirrer, 11.8 kg of deionized water, 575 g of t-butanol, 96 g of methanol, 60 g of ammonium perfluorooctanoate, 266 g of TFE, 29 g of propylene, 233 g of VDF, and 16.3 g (0.8 mol %) of CF 3 (OCF(CF 3 )CF 2 )OCF═CF 2 (a compound of the formula (3) wherein n=0 and m=1, hereinafter referred to as the perfluoro(alkyl vinyl ether)), were charged, and the temperature was raised to 70° C. Then, 180 ml of a 30% ammonium persulfate aqueous solution was injected to initiate polymerization. To supplement the pressure which decreased as the reaction progressed, a gas mixture comprising TFE/propylene/VDF in a molar ratio of 44/12/44, was introduced, and the reaction was continued under a pressure of 17.4 kg/cm 2 G. The perfluoro(alkyl vinyl ether) was added in an amount of 0.1 ml per 7 g of the gas mixture, and the reaction was continued for 7.7 hours. Then, the monomers in the reactor were purged to obtain 14.7 kg of a latex. Ammonium chloride was dropwise added to this latex for coagulation, followed by washing and drying to obtain 2.1 kg of copolymer e. The physical properties and mechanical properties of copolymer e were measured in the same manner as in Example 1, and the results are shown in Table 1.
EXAMPLE 6
To a deaerated stainless steel autoclave having an internal capacity of 20 l and equipped with a stirrer, 11.8 kg of deionized water, 158 g of methanol, 60 g of ammonium perfluorooctanoate, 210 g of TFE, 24 g of propylene, 243 g of VDF, and 37.4 g (1.5 mol %) of (perfluorooctyl)ethylene were changed, and the temperature was raised to 70° C. Then, 210 ml of a 30% ammonium persulfate aqueous solution was injected to initiate polymerization. To supplement the pressure which decreased as the reaction progressed, a gas mixture comprising TFE/propylene/VDF in a molar ratio of 35/8/57, was introduced, and the reaction was continued under a pressure of 18.2 kg/cm 2 G. (Perfluorooctyl)ethylene was added in an amount of 0.1 ml per 2 g of the gas mixture, and the reaction was continued for 11.3 hours. Then, the monomers in the reactor were purged to obtain 14.1 kg of a latex. Ammonium chloride was dropwise added to this latex for coagulation, followed by washing and drying to obtain 2.0 kg of copolymer f. The physical properties and mechanical properties of copolymer f were measured in the same manner as in Example 1, and the results are shown in Table 1.
EXAMPLE 7
To a deaerated stainless steel autoclave having an internal capacity of 20 l and equipped with a stirrer, 11.8 kg of deionized water, 520 g of t-butanol, 135 g of methanol, 50 g of ammonium perfluorooctanoate, 399 g of TFE, 44 g of propylene, 125 g of VDF, and 35 g (3.0 mol %) of perfluoro(propyl vinyl ether) were charge, and the temperature was raised to 70° C. Then, 180 ml of a 30% ammonium persulfate aqueous solution was injected to initiate polymerization. To supplement the pressure which decreased as the reaction progressed, a gas mixture comprising TFE/propylene/VDF in a molar ratio of 65/20/15, was introduced, and the reaction was continued under a pressure of 17.6 kg/cm 2 G. Perfluoro(propyl vinyl ether) was added in an amount of 0.1 ml per 5 g of the gas mixture, and the reaction was continued for 9.6 hours. Then, the monomers in the reactor were purged to obtain 15.2 kg of a latex. Ammonium chloride was dropwise added to this latex for coagulation, followed by washing and drying to obtain 2.3 kg of copolymer g. The physical properties and mechanical properties of copolymer g were measured in the same manner as in Example 1, and the results are shown in Table 1.
EXAMPLE 8 (COMPARATIVE EXAMPLE)
To a deaerated stainless steel autoclave having an internal capacity of 1 l and equipped with a stirrer, 635 g of deionized water, 5 g of ammonium perfluorooctanoate, 14.9 g of TFE, 1.4 g of propylene, 9.7 g of VDF were charged, and the temperature was raised to 80° C. Then, 5 ml of a 30% ammonium persulfate aqueous solution was injected to initiate polymerization. To supplement the pressure which decreased as the reaction progressed, a gas mixture comprising TFE/propylene/VDF in a molar ratio of 58/10/32, was introduced, and the reaction was continued for 6.5 hours under a pressure of 18.0 kg/cm 2 G. After completion of the reaction, the monomers in the reactor were purged to obtain 830 g of a latex. Sulfuric acid was dropwise added to this latex for coagulation, followed by washing and drying to obtain 182 g of copolymer h. The physical properties and mechanical properties of copolymer h were measured in the same manner as in Example 1, and the results are shown in Table 1.
EXAMPLE 9 (COMPARATIVE EXAMPLE)
To a deaerated stainless steel autoclave having an internal capacity of 1 l and equipped with a stirrer, 610 g of deionized water, 3.6 g of ammonium perfluorooctanoate, 14.8 g of disodium hydrogenphosphate 12 hydrate, 1.59 g of sodium hydroxide, 3 g of ammonium persulfate, 0.11 g of iron sulfate, 0.10 g of ethylenediamine tetracetate and 1.8 g of 2-butanol were charged. Then, 22.6 g of TFE, 3.5 g of propylene and 16.0 g of VDF were charged, and the temperature was maintained at 25° C. Then, 2 ml of a solution containing 1.76 g of sodium hydroxide and 0.29 g of Rongalite per 10 ml of water, was injected to initiate polymerization.
To supplement the pressure which decreased as the reaction progressed, a gas mixture comprising TFE/propylene/VDF in a molar ratio of 53/10/37, was introduced, and the reaction was continued under a pressure of 20.1 kg/cm 2 G. After 10 hours, the monomers in the reactor were purged to obtain 841 g of a latex. Sulfuric acid was dropwise added to this latex for coagulation, followed by washing and drying to obtain 202 g of copolymer i. The physical properties and mechanical properties of copolymer i were measured in the same manner as in Example 1, and the results are shown in Table 1.
TABLE 1______________________________________Example No. 1 2 3 4 5______________________________________CompositionTFE 59.9 58.6 53.8 70.9 44.3Propylene 11.4 12.2 13.8 9.7 13.1VDF 27.3 28.5 32.0 15.6 41.9PFBE 1.4 0.7 -- -- --PFOE -- -- 0.4 -- --PPVE -- -- -- 3.9 --PAVE -- -- -- -- 0.7Melting point 139 144 141 136 113Volumetric 2.8 7.4 3.2 1.0 0.8flow rateTensile 230 220 180 89 117modulus ofelasticityAt 25° C.Tensile 236 171 218 181 195strengthTensile 466 496 487 460 524elongation (%)At 100° C.Tensile 30 27 29 21 25strengthTensile 1052 688 884 476 729elongation (%)______________________________________Example No. 6 7 8 9______________________________________CompositionTFE 37.8 67.4 60.7 54.7Propylene 7.8 19.7 9.7 15.4VDF 53.2 11.8 29.6 29.9PFBE -- -- -- --PFOE 1.2 -- -- --PPVE -- 1.1 -- --PAVE -- -- -- --Melting point 107 154 142 149Volumetric 2.2 5.7 1.8 0.9flow rateTensile 102 247 190 210modulus ofelasticityAt 25° C.Tensile 184 251 106 121strengthTensile 549 457 192 468elongation (%)At 100° C.Tensile 19 34 17 19strengthTensile 692 869 62 88elongation (%)______________________________________ PFBE: (Perfluorobutyl)ethylene PFOE: (Perfluorooctyl)ethylene PPVE: Perfluoro(propyl vinyl ether) PAVE: CF.sub.3 (OCF(CF.sub.3)CF.sub.2)OCF = CF.sub.2
As described in the foregoing, the thermoplastic fluorine-containing copolymer of the present invention obtained by polymerizing TFE, propylene, VDF and, as the fourth component, at least one fluorinated comonomer selected from those of the formulae (1), (2) and (3), has flexibility, transparency and excellent high temperature mechanical properties.
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A fluorine-containing copolymer comprising:
(a) from 0.05 to 20 mol % of polymer units based on at least one fluorinated comonomer selected from the group consisting of fluorinated comonomers of the following formulae (1), (2) and (3):
X--R.sup.f --CY═CH.sub.2 (1)
X--R.sup.f --O--CF═CF.sub.2 (2)
CF.sub.3 --(CF.sub.2).sub.n --(O--CF(CF.sub.3)--CF.sub.2).sub.m
--O--CF═CF 2 (3)
wherein Y is a fluorine atom or a hydrogen atom, R f is a C 2-12 bivalent fluorinated organic group, X is a fluorine atom, a chlorine atom or a hydrogen atom, n is an integer of from 0 to 3, and m is an integer of from 1 to 4,
(b) from 30 to 85 mol % of polymer units based on tetrafluoroethylene,
(c) from 1 to 30 mol % of polymer units based on propylene, and
(d) from 5 to 68.5 mol % of polymer units based on vinylidene fluoride.
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[0001] This application claims priority under 35 U.S.C. §119 to patent application no. DE 10 2015 201 727.3, filed on Feb. 2, 2015 in Germany, the disclosure of which is incorporated herein by reference in its entirety.
[0002] The disclosure relates to an internal gear pump for a hydraulic vehicle brake system. The disclosure furthermore relates to a method for producing the internal gear pump.
BACKGROUND
[0003] Modern brake-assistance and driving dynamics systems almost exclusively use oscillating positive displacement pumps as high pressure generating unit. Leakage passes over a circumference of a piston and along a guide length in a stationary cylinder.
[0004] Rotating positive displacement pumps have axial and radial leakage gaps between individual chambers of the displacement gear components. Internal gear pumps have leakage gaps for example axially on the end sides of the gear wheels, i.e. of the pinion and of the ring gear. This results in a conflict of objectives between minimal leakage and minimal friction of the rotating positive displacement pump.
[0005] DE 10 2013 201 384 A1 discloses an internal gear pump for a hydraulic vehicle brake system, having a pump shaft on which a pinion is arranged for conjoint rotation, having a ring gear which meshes with the pinion, and having a rotationally fixed axial disk which is arranged on and bears in a sealing manner against an end side of the pinion and of the ring gear.
SUMMARY
[0006] The present disclosure creates an internal gear pump for a hydraulic vehicle brake system, having a pump shaft on which a pinion is arranged for conjoint rotation, having a ring gear, wherein the pinion is arranged eccentrically in the ring gear and meshes with the ring gear, having a first axial plate which is arranged on a first end side of the pinion and of the ring gear, and having a second axial plate which is arranged on a second end side of the pinion and of the ring gear, wherein the first axial plate and the second axial plate delimit a pump chamber in the axial direction, wherein a toothing on the pinion and/or on the ring gear is configured such that an axial width of a tooth root of a respective tooth is configured to be greater than an axial width of a tooth crest of the respective tooth.
[0007] The present disclosure furthermore creates a method for producing an internal gear pump for a hydraulic vehicle brake system. The method comprises providing a pump shaft. In addition, the method comprises arranging a pinion on the pump shaft for conjoint rotation. The method moreover comprises arranging a ring gear eccentrically relative to the pinion on the pump shaft, wherein the pinion meshes with the ring gear. The method additionally comprises arranging a first axial plate on the pump shaft on a first end side of the pinion and of the ring gear. The method furthermore comprises arranging a second axial plate on the pump shaft on a second end side of the pinion and of the ring gear, wherein the first axial plate and the second axial plate delimit a pump chamber in the axial direction, wherein a toothing on the pinion and/or on the ring gear is configured such that an axial width of a tooth root of a respective tooth is configured to be greater than an axial width of a tooth crest of the respective tooth.
[0008] It is an idea of the present disclosure to increase the mechanical and hydraulic efficiency and also the service life of an internal gear pump. In the internal gear pump according to the disclosure, friction occurs between gear wheels and axially abutting plates that compensate for a leakage gap. This friction is reduced in that the axial width of the tooth root of a respective tooth is configured to be greater than an axial width of a tooth crest of the respective tooth on the pinion and/or on the ring gear. In this way, the internal gear pump can be operated in a fluid friction mode in operation. Advantageous embodiments and developments can be gathered from the claims and from the description with reference to the figures.
[0009] According to a preferred development, provision is made for an end-side surface of respective tooth flanks and/or tooth crest faces of the toothing on the pinion and/or on the ring gear to be configured in an at least partially convex manner. In this way, the solid contact pressure between the pinion and/or the ring gear and the axial plates abutting in each case in a sealing manner can be minimized.
[0010] According to a further preferred development, provision is made for a height of a convexity of the end-side surface of respective tooth flanks and/or tooth crest faces of the toothing on the pinion and/or on the ring gear to be between 10 nm and 1 mm. This allows a minimum lubrication gap height. Furthermore, when the internal gear pump is started up and shut down and when it runs down, solid body friction and/or mixed friction that occurs as a matter of principle can already be replaced with fluid friction at low pump speeds. In this way, the reliability can be increased considerably, in particular in vehicle applications having for example a high proportion of starting/stopping and/or when coasting.
[0011] According to a further preferred development, provision is made for the end-side surface of the respective tooth flanks and/or of the tooth crest faces of the toothing on the pinion and/or on the ring gear to be configured as a freeform surface in the form of at least one spline or as a geometrically defined surface conically, cylindrically or as a logarithmically profiled form. The design of the above-described geometrically topographical structures allows the solid contact pressure and as a result the operation of the internal gear pump in the fluid friction range to be minimized. As a result of a reduction in the mechanical friction of the pump, the required drive power is lowered substantially. A leakage flow between the components is advantageously reduced. Furthermore, the reliability of the components can be increased by the dominant proportion of fluid friction.
[0012] According to a further preferred development, provision is made for a surface of the first axial plate and/or of the second axial plate to be configured, at least in a region adjacent to the toothing on the pinion and/or on the ring gear, as a freeform surface in the form of at least one spline or as a geometrically defined surface conically, cylindrically or as a logarithmically profiled form. In this way, in addition to a modification of the tooth flanks and/or tooth crest faces of the toothing on the pinion and/or on the ring gear, further hydrodynamic effects can be created and thus the mechanical friction in the internal gear pump can additionally be reduced.
[0013] According to a further preferred development, provision is made for a length of the end-side surface of the tooth flanks and/or of the tooth crest faces of the toothing on the pinion and/or on the ring gear to be from 10 μm to 1 mm. This allows a minimum lubrication gap height. Furthermore, when the internal gear pump is started up and shut down and when it runs down, solid body friction and/or mixed friction that occurs as a matter of principle can already be replaced with fluid friction at low pump speeds. In this way, the reliability is increased considerably, in particular in vehicle applications having for example a high start/stop proportion and/or when coasting.
[0014] According to a further preferred development, provision is made for the end-side surface of respective tooth flanks and/or tooth crest faces of the toothing on the pinion and/or on the ring gear to be formed by lapping, grinding, turning and/or turn milling. In this way, the surface of the tooth flanks and/or of the tooth crest faces of the toothing on the pinion and/or on the ring gear can be machined such as to allow the solid contact pressure in the internal gear pump to be minimized.
[0015] According to a further preferred development, provision is made for the first axial plate and the second axial plate each to be configured as a disklike plate embodied in a one-part or multipart manner. In this way, the first and the second axial plate can be adapted in an advantageous manner to the respective structural requirements placed on the internal gear pump.
[0016] According to a further preferred development, provision is made for the end-side surface of respective tooth flanks and/or tooth crest faces of the toothing on the pinion and/or on the ring gear to be formed by lapping, grinding, turning and/or turn milling. In this way, the surface of the tooth flanks and/or of the tooth crest faces of the toothing on the pinion and/or on the ring gear can be machined such as to allow the solid contact pressure in the internal gear pump to be minimized.
[0017] The described configurations and developments can be combined with one another as desired.
[0018] Further possible configurations, developments and implementations of the disclosure also comprise combinations, not explicitly mentioned, of features of the disclosure that are described above or in the following text with regard to the exemplary embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The accompanying drawings are intended to convey further understanding of the embodiments of the disclosure. They illustrate embodiments and serve, in conjunction with the description, to explain principles and concepts of the disclosure.
[0020] Other embodiments and many of the advantages mentioned can be gathered with regard to the drawings. The illustrated elements of the drawings are not necessarily shown true to scale with respect to one another.
[0021] In the drawings:
[0022] FIG. 1 shows an exploded illustration of an internal gear pump for a hydraulic vehicle brake system according to a preferred embodiment of the disclosure;
[0023] FIG. 2 shows a schematic illustration of a pinion of the internal gear pump according to the preferred embodiment of the disclosure;
[0024] FIG. 3 shows a cross-sectional view of the pinion shown in FIG. 2 according to the preferred embodiment of the disclosure;
[0025] FIG. 4 shows a view in longitudinal section of the internal gear pump in the mounted state according to the preferred embodiment of the disclosure;
[0026] FIG. 5 shows a schematic illustration of the pinion of the internal gear pump according to a further embodiment of the disclosure;
[0027] FIG. 6 shows a cross-sectional view of the pinion of the internal gear pump according to the further preferred embodiment of the disclosure;
[0028] FIG. 7 shows a schematic illustration of a ring gear of the internal gear pump according to the further preferred embodiment of the disclosure;
[0029] FIG. 8 shows a cross-sectional view of the ring gear of the internal gear pump according to the further preferred embodiment of the disclosure;
[0030] FIG. 9 shows a view in longitudinal section of the internal gear pump in the mounted state according to the further preferred embodiment of the disclosure; and
[0031] FIG. 10 shows a flow chart of a method for producing an internal gear pump for a hydraulic vehicle brake system according to the preferred embodiment of the disclosure.
DETAILED DESCRIPTION
[0032] In the figures of the drawings, identical reference signs denote identical or functionally identical elements, parts or components, unless stated to the contrary.
[0033] FIG. 1 shows an exploded illustration of an internal gear pump for a hydraulic vehicle brake system according to a preferred embodiment of the disclosure.
[0034] The internal gear pump 1 has a housing 2 , a sealing ring 3 , a pump shaft 5 , a pinion 10 , a ring gear 12 , a crescent 13 , a first axial plate 14 and a second axial plate 15 . The pump shaft 5 is arranged so as to extend through the first axial plate 14 , the pinion 10 , the ring gear 12 , the second axial plate 15 and the housing 2 .
[0035] The pinion 10 is arranged on the pump shaft 5 for conjoint rotation. The pinion 10 is arranged (in a mounted state, not shown in FIG. 1 , of the internal gear pump) eccentrically in the ring gear 12 and meshes with the latter. The crescent 13 is likewise arranged eccentrically in the ring gear 12 , in particular between the pinion 10 and an inner circumference of the ring gear 12 . The pinion 10 has a toothing 18 on an outer circumference. The ring gear 12 has a toothing 20 on an inner circumference. The toothing 18 on the pinion 10 is configured such that it is suitable for meshing with the toothing 20 on the ring gear 12 . The first axial plate 14 is arranged on a first end side of the pinion 10 and of the ring gear 12 and bears against them in a sealing manner. The second axial plate 15 is arranged on a second end side of the pinion 10 and of the ring gear 12 and bears against them in a sealing manner. The first axial plate 14 , the pinion 10 , the ring gear 12 , the crescent 13 and the second axial plate 15 form a pump chamber 16 .
[0036] FIG. 2 shows a schematic illustration of a pinion of the internal gear pump according to the preferred embodiment of the disclosure. The pinion 10 preferably has the toothing 18 formed on an outer circumference of the pinion 10 . A respective tooth 19 of the toothing 18 on the pinion 10 has a tooth root 19 a and a tooth crest 19 b.
[0037] FIG. 3 shows a cross-sectional view of the pinion shown in FIG. 2 according to the preferred embodiment of the disclosure. The tooth 19 has the tooth root 19 a, the tooth crest 19 b, respective tooth flanks 19 c and a tooth crest face 19 d. The tooth 19 preferably has a predetermined geometric shape which is configured such that an axial width B 1 of the tooth root 19 a is configured to be greater than an axial width B 2 of the tooth crest 19 b.
[0038] The tooth flanks 19 c of the tooth 19 are preferably beveled in the present embodiment. A height
[0039] H of the slope of the respective tooth flanks 19 c is preferably between 10 nm and 1 mm. A length L of the end-side surface of the respective tooth flanks 19 c is preferably between 10 μm and 1 mm. The tooth crest face 19 d of the tooth 19 is configured in a planar manner in the present embodiment.
[0040] FIG. 4 shows a view in longitudinal section of the internal gear pump in the mounted state according to the preferred embodiment of the disclosure. The pinion 10 is preferably arranged eccentrically in the ring gear 12 and meshes with the latter. The first axial plate 14 is arranged on a first end side of the pinion 10 and of the ring gear 12 . The second axial plate 15 is arranged on a second end side of the pinion 10 and of the ring gear 12 . The first axial plate 14 and the second axial plate 15 each bear in a sealing manner against the pinion 10 and the ring gear 12 .
[0041] FIG. 5 shows a schematic illustration of the pinion of the internal gear pump according to a further preferred embodiment of the disclosure. The pinion 10 preferably has the toothing 18 formed on an outer circumference of the pinion 10 . A respective tooth 19 of the toothing 18 on the pinion 10 has a tooth root 19 a and a tooth crest 19 b.
[0042] FIG. 6 shows a cross-sectional view of the pinion of the internal gear pump according to the further preferred embodiment of the disclosure. The tooth 19 has the tooth root 19 a, the tooth crest 19 b, respective tooth flanks 19 c and a tooth crest face 19 d. An end-side surface of the respective tooth flanks 19 c of the tooth 19 are configured in a partially convex manner in the present embodiment. A length L of the end-side surface of the tooth flanks 19 c is preferably between 10 μm and 1 mm.
[0043] A height H of a convexity of the end-side surface of the respective tooth flanks 19 c is preferably between 10 nm and 1 mm. Alternatively, the length L of the end-side surface of the respective tooth flanks 19 c and the height H of the convexity of the end-side surface of the respective tooth flanks 19 c can also have another suitable dimension.
[0044] Alternatively to the convex shaping, the respective tooth flanks 19 c of the tooth 19 can be configured for example as a freeform surface in the form of at least one spline or as a geometrically defined surface conically, cylindrically or as a logarithmically profiled form.
[0045] FIG. 7 shows a schematic illustration of a ring gear of the internal gear pump according to the further preferred embodiment of the disclosure. The ring gear 12 has the toothing 20 on an inner circumference. Respective teeth 21 of the toothing 20 each have a tooth root 21 a, a tooth crest 21 b, respective tooth flanks 21 c and a tooth crest face 21 d.
[0046] FIG. 8 shows a cross-sectional view of the ring gear of the internal gear pump according to the further preferred embodiment of the disclosure.
[0047] The ring gear 12 preferably has the toothing 20 . An axial width B 1 of the tooth root 21 a of the respective tooth 21 is preferably configured to be greater than an axial width B 2 of a tooth crest 21 b of the respective tooth 21 .
[0048] In the present embodiment, the end-side surface of respective tooth flanks 21 c of the toothing 20 on the ring gear 12 is preferably configured in a partially convex manner. A height H of a convexity of the end-side surface of respective tooth flanks 21 c of the toothing 20 on the ring gear 12 is preferably between 10 nm and 1 mm. A length L of the end-side surface of the tooth flanks 21 c of the toothing 20 on the ring gear 12 is preferably between 10 μm and 1 mm.
[0049] Alternatively to the partially convex configuration of the end-side surface of respective tooth flanks 21 c of the toothing 20 on the ring gear 12 , said surface can be configured for example as a freeform surface in the form of at least one spline or as a geometrically defined surface conically, cylindrically or as a logarithmically profiled form.
[0050] The end-side surface of respective tooth flanks 19 c, 21 c and/or tooth crest faces 19 d, 21 d of the toothing 18 , 20 on the pinion 10 and/or on the ring gear 12 is preferably formed by lapping, grinding, turning and/or turn milling.
[0051] FIG. 9 shows a view in longitudinal section of the internal gear pump in the mounted state according to the further preferred embodiment of the disclosure. The pinion 10 is preferably arranged eccentrically in the ring gear 12 and meshes with the latter. The first axial plate 14 is arranged on a first end side of the pinion 10 and of the ring gear 12 . The second axial plate 15 is arranged on a second end side of the pinion 10 and of the ring gear 12 . The first axial plate 14 and the second axial plate 15 each bear in a sealing manner against the pinion 10 and the ring gear 12 .
[0052] The first axial plate 14 and the second axial plate 15 are preferably configured in a one-part manner. Alternatively, the first axial plate 14 and the second axial plate 15 can also be configured in a multipart manner.
[0053] In addition, a surface 14 a, 15 a of the first axial plate 14 and/or of the second axial plate 15 can be configured, in a region adjacent to the toothing 18 , 20 on the pinion 10 and/or on the ring gear 12 , as a freeform surface in the form of at least one spline or as a geometrically defined surface conically, cylindrically or as a logarithmically profiled form.
[0054] The geometrically defined surfaces or topographical configurations can preferably be oriented in one and/or a plurality of directions.
[0055] FIG. 10 shows a flow chart of a method for producing an internal gear pump for a hydraulic vehicle brake system according to the preferred embodiment of the disclosure.
[0056] The method comprises providing S 1 a pump shaft. In addition, the method comprises arranging S 2 a pinion on the pump shaft for conjoint rotation. The method moreover comprises arranging S 3 a ring gear eccentrically relative to the pinion on the pump shaft, wherein the pinion meshes with the ring gear. The method additionally comprises arranging S 4 a first axial plate on the pump shaft on a first end side of the pinion and of the ring gear. The method furthermore comprises arranging S 5 a second axial plate on the pump shaft on a second end side of the pinion and of the ring gear, wherein the first axial plate and the second axial plate delimit a pump chamber in the axial direction, wherein a toothing on the pinion and/or on the ring gear is configured such that an axial width of a tooth root of a respective tooth is configured to be greater than an axial width of a tooth crest of the respective tooth.
[0057] An end-side surface of respective tooth flanks and/or tooth crest faces of the toothing on the pinion and/or on the ring gear are preferably configured in an at least partially convex manner.
[0058] The end-side surface of the respective tooth flanks and/or of the tooth crest faces of the toothing on the pinion and/or on the ring gear is preferably configured as a freeform surface in the form of at least one spline or as a geometrically defined surface conically, cylindrically or as a logarithmically profiled form.
[0059] A surface of the first axial plate and/or of the second axial plate is preferably configured, at least in a region adjacent to the toothing on the pinion and/or on the ring gear, as a freeform surface in the form of splines or as a geometrically defined surface conically, cylindrically or as a logarithmically profiled form.
[0060] The first axial plate and the second axial plate are preferably each configured as a disklike plate embodied in a one-part or multipart manner.
[0061] The end-side surface of respective tooth flanks and/or tooth crest faces of the toothing on the pinion and/or on the ring gear is preferably formed by lapping, grinding, turning and/or turn milling.
[0062] Although the present disclosure has been described here with reference to preferred exemplary embodiments, it is not limited thereto but is modifiable in a wide variety of ways. In particular, the disclosure can be altered or modified in various ways without departing from the essence of the disclosure.
[0063] For example, the end-side surface of respective tooth flanks of the toothing on the ring gear can alternatively be beveled analogously to the preferred embodiment of the pinion. The slope is preferably constant and has a predetermined inclination. Alternatively to the provision of an internal gear pump, the present disclosure is also applicable for example to an external gear pump or gerotor pump.
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An internal gear pump for a hydraulic vehicle brake system includes a pump shaft, a pinion, a ring gear, a first axial plate, and a second axial plate. The pinion is disposed on the pump shaft, is configured to rotate conjointly therewith, and is arranged eccentrically within the ring gear so as to mesh therewith. The first and second axial plates are adjacent to the pinion and the ring gear. A toothing on at least one of the ring gear and the pinion is configured such that an axial width of a root of a respective tooth is greater than an axial width of a crest of the respective tooth. A corresponding method relates to producing such an internal gear pump.
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FIELD OF THE INVENTION
The present invention relates to semiconductor memory systems, such as static random access memory (SRAM) systems or dynamic random access memory (DRAM) systems. More specifically, the present invention relates to a memory system including an error detection and correction system.
DISCUSSION OF RELATED ART
Semiconductors memories such as DRAM and SRAM devices are susceptible to both soft and hard errors. Soft errors are generated when sub-atomic energetic particles hit the memory device and generate charge high enough to upset the state of one or more memory cells. Hard errors are generated by defects in the semiconductor device during the manufacturing process. The incorporation of error detection and correction circuitry in memory devices has been described in many prior art schemes.
For example, U.S. Pat. No. 5,638,385, entitled “Fast Check Bit Write For A Semiconductor Memory” by John A. Fifield et al., describes the use of error-correction codes (ECC), such as error-correction check bits, in a memory using two different types of memory cells. Smaller and slower memory cells are used to store data bits, while larger and faster memory cells are for storing error-correction check bits. The faster cells provide faster write access to the error-correction check bits, thereby compensating for the delay associated with the generation of the error-correction check bits, and minimizing the impact of the ECC generation on the overall memory write latency. This, however, is accomplished at the cost of larger area.
U.S. Pat. No. 6,065,146, entitled “Error Correcting Memory” by Patrick Bosshart, describes an error-correcting memory that imposes no penalty on memory access latency or operating frequency. This error-correcting memory performs error correction only during a refresh operation of the memory, during a second or subsequent read operation of a burst read sequence, or during a write-back operation. As a result, the error correction scheme does not increase the read latency of the memory. Similarly, error correction check bits are only generated during refresh operations of the memory. As a result, the generation of error correction check bits does not increase the write latency of the memory. However, this error correction scheme cannot correct data errors occurring in the first read operation of a burst read sequence, or in data written to the memory before the error correction check bits are generated.
U.S. Pat. No. 5,003,542, entitled “Semiconductor Memory Device Having Error Correcting Circuit and Method For Correcting Error”, by Koichiro Mashiko, et al., describes a memory that includes ECC circuitry incorporated in the sense amplifier area of the memory. More specifically, a second set of sense amplifiers and ECC correction logic is coupled to the bit lines of the memory array, thereby speeding up the error correction process by eliminating delays through the input/output (I/O) circuitry. However, this scheme requires that a second set of sense amplifiers and ECC correction logic be incorporated in each memory array. In general, there are many memory arrays in a memory device. As a result, this arrangement increases the array area and thus the silicon area of the memory. In addition, even though delays through the I/O circuit are eliminated, the delays through the ECC correction circuit still increase the memory cycle time. For a high-frequency memory, this increase is significant.
It would therefore be desirable to have an improved error detection and correction scheme that overcomes the above-described deficiencies of the prior art.
SUMMARY
Accordingly, the present invention provides a memory device or an embedded memory block that includes an array of memory cells with built-in ECC protection. In one embodiment, the memory cells are DRAM cells. In another embodiment, the memory cells are SRAM cells. The error-correction code function is designed so that the error-correction code generation does not increase the write access time of the memory device. The scheme also provides for write-back of corrected data without decreasing the operating frequency of the memory device.
To eliminate the effect of ECC generation on the write access time, a write buffer is used to facilitate a posted write scheme. During a first write access, a first write data value and the corresponding first write address are stored in a first entry of the write buffer. At this time, an error correction circuit generates a first error correction code in response to the first write data value. During a second write access, the first write data value and the first error correction code are transferred to a second entry of the write buffer and retired to the memory array. At the same time, a second write data value and a corresponding second write address are stored in the first entry of the write buffer. After the second write data value is stored in the first entry of the write buffer, the error correction circuit generates a second error correction code in response to the second write data value. The second write data value, second write address and second error correction code are stored in the write buffer until the next write operation. Because the error correction code is generated in parallel with the retiring of a previous write data value, and because the error correction circuit and write buffer operate faster than the memory array, the error correction code generation does not impose a penalty on the memory cycle time or the write access time.
Error detection and correction is also performed on data values read from the memory device. During a read access, a read data value and the corresponding ECC word are read from the memory array and provided to an error detection-correction circuit. The error detection-correction circuit provides a corrected read data value that is driven to the output of the memory device. The error detection-correction circuit also provides a corrected ECC word, and an error indicator signal, which indicates whether the read data value or corresponding ECC word included an error. In one embodiment, the error indicator signal indicates whether the read data value or corresponding ECC word included a single error bit. If the error indicator signal is activated, the corrected read data value and corrected ECC word are posted in the write-back buffer at the same time that the corrected read data value is driven to the output of the memory device. The corrected read data value and ECC word in the write-back buffer are retired to the memory array during an idle cycle of the memory array, during which no external access is performed. By retiring the corrected read data value and ECC word during an idle cycle, the write-back scheme does not have an adverse affect on the memory cycle time.
The number of entries in the write-back buffer is limited. Therefore the entries of the write-back buffer can be exhausted during a period of many consecutive read accesses that have correctable errors. In this case, an allocation policy can be executed to either drop the earliest entry in the write-back buffer (FIFO policy) or stop accepting entries in the write-back buffer (LIFO policy). The chance of having to invoke the allocation policy is small, because the number of words containing errors in the memory at a given time is small. The chance of reading all of these error words without a sufficient number of idle cycles in between is even smaller. Moreover, the allocation policy does not stop the memory device from functioning correctly, because a read data value/ECC word that contains an error, but cannot be posted in the write-back buffer, can still be accessed from the memory array, corrected by the error detection-correction circuit, and then driven to the memory output, as long as the data value/ECC word does not accumulate more error bits than the error correction circuit can correct. The write-back buffering decouples the memory array operation from the error correction operation, because the memory array does not need to wait for the corrected data before completing the access cycle. Therefore, the memory cycle time is not affected by the write-back operation. The read latency, however, is increased, because the data needs to propagate through the error detection correction unit before being driven to the output of the memory.
The present invention will be more fully understood in view of the following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a memory device in accordance with one embodiment of the present invention.
FIG. 2 is a block diagram of a write buffer-error correction code (ECC) generator in accordance with one embodiment of the present invention.
FIG. 3 is a circuit diagram illustrating a write-back buffer in accordance with one embodiment of the present invention.
FIG. 4 is a waveform diagram illustrating the timing of a write access in accordance with one embodiment of the present invention.
FIG. 5 is a waveform diagram illustrating the timing of a read transaction followed by a write-back operation in accordance with one embodiment of the present invention.
FIG. 6 is a waveform diagram illustrating the timing of two consecutive read access cycles followed by two consecutive write-back cycles in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION
FIG. 1 is a block diagram of a memory device 100 in accordance with one embodiment of the present invention. Memory device 100 includes memory array 101 , memory array sequencer 102 , address register 103 , multiplexer 104 , write buffer/ECC generator 105 , error detection/correction circuit 106 , write-back buffer 107 , output driver 108 and NOR gate 109 . The external interface of memory device 100 includes a 64-bit input data bus Di[ 63 : 0 ], a 64-bit output data bus Do[ 63 : 0 ], a read enable line REN, a write enable line WEN, a clock line CLK, and a 15-bit address bus A[ 14 : 0 ]. In the described embodiments, each bus/line and the corresponding signal are identified using the same reference element. For example, Di[ 63 : 0 ] is used to identify both the input data bus and the input data value transmitted on the input data bus.
In the described example, memory array 101 is a conventional 32k×72-bit memory array, although this is not necessary. In the described embodiment, memory array 101 includes a plurality of sub-arrays. Each sub-array includes word line drivers for the activation of a selected word line, and sense-amplifiers for the amplification of signals from the selected memory cells. Memory array 101 also contains address decoders for accessing the memory cells selected by the memory address MA[ 14 : 0 ] provided by multiplexer 104 . Memory array 101 includes circuitry that is well known to those of ordinary skill in the art of memory design.
Memory array 101 uses DRAM cells in the described embodiment, although SRAM cells can be used in an alternate embodiment. The refresh of the DRAM cells is managed by circuitry outside of memory device 100 by performing periodic read accesses on all of the word lines of memory array 101 . Additional logic can also be easily incorporated to adapt to the refresh scheme described in commonly-owned U.S. Pat. No. 6,028,804, “Method and Apparatus For 1-T SRAM Compatible Memory”. The operation of memory array 101 is controlled by memory array sequencer 102 , which generates a row access select signal RAS#, a sense amplifier enable signal SEN#, a column address select signal CAS# and a pre-charge signal PRC#. The functionality of these control signals and the operation of memory array sequencer 102 are described in more detail in commonly owned U.S. Pat. No. 6,147,535, entitled “Clock Phase Generator For Controlling Operation of a DRAM Array”. In the described embodiment, memory array sequencer 102 sequentially asserts the RAS#, SEN#, CAS# and PRC# signals in a predetermined manner to enable a memory access to be completed during a single clock cycle.
Address multiplexer 104 routes an input address MA[ 14 : 0 ] to memory array 101 from one of three different sources. One source is a latched address signal LA[ 14 : 0 ], which is driven by the output of address register 103 . Another source is the write buffer tag address WBTag[ 14 : 0 ], which is driven by the address field of write buffer/ECC generator 105 . The third source is the write-back buffer tag address WBBTag[ 14 : 0 ], which is driven by the address field of write-back buffer 107 . Address multiplexer 104 is controlled by the read enable signal REN and the write enable signal WEN. As described in more detail below, multiplexer 104 passes the latched address signal LA[ 14 : 0 ] during a read operation, when the read enable signal REN is asserted and the write enable signal WEN is de-asserted. Multiplexer 104 passes the write buffer tag address WBTag[ 14 : 0 ] during a write operation, when the write enable signal WEN is asserted and the read enable signal REN is de-asserted. Finally, multiplexer 104 passes the write-back buffer tag address WBBTag[ 14 : 0 ] during a write-back operation, when both the write enable signal WEN and the read enable signal REN are de-asserted.
Data input to memory array 101 and data output from memory array 101 is transmitted as a 72-bit memory data word MD[ 71 : 0 ] on a 72-bit data bus. The 72-bit data word MD[ 71 : 0 ] includes two fields: a 64-bit data field and a 8-bit error correction code (ECC) field. At the beginning of a memory cycle (as indicated by the falling edge of the RAS# signal), the 72-bit memory data word MD[ 71 : 0 ] is latched into a data register (not shown) in memory array 101 .
FIG. 2 is a block diagram of write buffer/ECC generator 105 in accordance with one embodiment of the present invention. In the described embodiment, write buffer/ECC generator 105 includes input register 200 , output register 201 , error correction code (ECC) generator 202 , AND gates 203 – 204 , comparator 205 , OR gates 206 – 207 , D type flip-flop 208 , and tri-state output buffers 210 – 211 . Write buffer/ECC generator 105 includes registers 200 and 201 . Registers 200 – 201 are configured into a first-in, first-out (FIFO) configuration. Input register 200 contains 79-bits for storing one address entry (15-bits) and one data entry (64-bits). Output register 201 contains 87-bits for storing one address entry (15-bits), one data entry (64-bits), and the associated error correction code (8-bits) generated by ECC generator 202 .
Write buffer/ECC generator 105 operates as follows. At the beginning of a first memory write access, a first write data value Di 1 [ 63 : 0 ] and a corresponding first write address Ai 1 [ 14 : 0 ] are applied to input register 200 , and the write enable signal WEN is asserted high. The clock signal CLK subsequently transitions to a logic high state, thereby causing AND gate 203 to provide a logic high signal to enable input register 200 . In response, input register 200 latches the first write data value Di 1 [ 63 : 0 ] and the corresponding first write address Ai 1 [ 14 : 0 ]. The first write data value Di 1 [ 63 : 0 ] is applied to ECC generator 202 . In response, ECC generator 202 generates a first error correction check bit signal CB 1 [ 7 : 0 ].
At the beginning of a second (subsequent) memory write access, a second write data value Di 2 [ 63 : 0 ] and a corresponding second write address Ai 2 [ 14 : 0 ] are applied to input register 200 , and the write enable signal WEN is asserted to a logic high value. The clock signal CLK subsequently transitions to a logic high value, thereby causing AND gate 203 to provide a logic high signal to enable register 200 , and causing OR gate 206 to provide a logic high signal to enable register 201 . In response, the first write data value Di 1 [ 63 : 0 ], the first write address Ai 1 [ 14 : 0 ] and the first check bit CB 1 [ 7 : 0 ] are latched into output register 201 . In addition, the second write data value Di 2 [ 63 : 0 ] and the second write address Ai 2 [ 14 : 0 ] are latched into input register 200 .
The logic high write enable signal WEN also causes OR gate 207 to provide a logic high signal to flip-flop 208 . This logic high signal is latched into flip-flop 208 in response to the rising edge of the CLK signal. As a result, flip-flop 208 provides a logic high signal to the enable terminals of tri-state output buffers 210 and 211 , thereby enabling these buffers. In response, output buffers 210 and 211 drive the first write data value Di 1 [ 63 : 0 ] and the first check bit CB 1 [ 7 : 0 ] from output register 201 to memory data bus MD[ 71 : 0 ]. The first write address value Ai 1 [ 14 : 0 ] is routed from output register 201 as write buffer tag address WBTag[ 14 : 0 ]. The write buffer tag address WBTag[ 14 : 0 ] is routed through multiplexer 104 to memory array 101 ( FIG. 1 ) in response to the logic high WEN signal and the logic low REN signal. The first write data value Di 1 [ 63 : 0 ] and the first check bit CB 1 [ 7 : 0 ] (i.e., memory data word MD[ 71 : 0 ]) is written to memory array 101 at the location identified by write buffer tag address WBTag[ 14 : 0 ].
In the foregoing manner, write buffer/ECC generator 105 operates as a posted write buffer. That is, during a write access cycle, data and address values previously posted to write buffer/ECC generator 105 are used to perform a write access to memory array 101 . New data and address values are posted to register 200 , and corresponding check bits are generated during the same write access cycle. Registers 200 - 201 and ECC generator 202 are significantly faster than memory array 101 . As a result, the operations performed within write buffer/ECC generator 105 do not slow down write accesses to memory array 101 .
Note that it is necessary to maintain data coherence if a read access hits the contents of write buffer/ECC generator 105 . To maintain data coherence, comparator 205 is coupled to receive both the current access address A[ 14 : 0 ] and the write address previously posted to input register 200 . Comparator 205 asserts a logic high MATCH output signal if the current access address matches the write address stored in input register 200 . The MATCH signal and the read enable signal REN are both provided to AND gate 204 . If comparator 205 detects a match, and the current access is a read access (REN=“1”), then AND gate 204 will assert a logic high write buffer hit signal WBHit, thereby indicating that the current read access has hit the contents of write buffer/ECC generator 105 .
The WBHit signal is applied to an input terminal of memory access sequencer 102 . When the WBHit signal is asserted to a logic high value, memory access sequencer 102 is prevented from generating the access control signals RAS#, SEN#, CAS#, and PRC#, thereby suppressing access to memory array 101 . Instead, the read data is provided by write buffer/ECC generator 105 in the manner described below.
Within write buffer/ECC generator 105 , the WBHit signal is applied to input terminals of OR gates 206 and 207 . Thus, when the WBHit signal is asserted high, OR gate 206 provides a logic high signal to the clock input terminal of register 201 . Consequently, the write data, write address and associated check bits stored in input register 200 are latched into output register 201 at this time. OR gate 207 provides a logic high signal to flip-flop 208 . This logic high signal is latched into flip-flop 208 in response to the rising edge of the CLK signal. Tri-state output buffers 210 and 211 are enabled in response to the logic high signal latched into flip-flop 208 . As a result, the data value and the corresponding ECC value stored in output register 201 are driven onto data bus MD[ 71 : 0 ]. The data and ECC values on data bus MD[ 71 : 0 ] are routed to error detection/correction unit 106 . In response, error detection/correction unit 106 provides a corrected data value, which is routed through output driver 108 to data output bus Do[ 63 : 0 ], thereby completing the read access.
Although the present example uses output register 201 , this element of write buffer 105 is not required in all embodiments. For example, the address stored in input register 200 can be driven directly as the write buffer tag address WBTag[ 14 : 0 ], the data value stored in input register 200 can be provided directly to output driver 210 , and the corresponding check bits CB[ 7 : 0 ] can be provided directly to output driver 211 . During a subsequent write operation, the data and address values stored in register 200 and the check bits provided by ECC generator 202 are latched directly into registers in memory array 101 , thereby eliminating the need for output register 201 .
Error Detection-Correction
Error detection/correction circuit 106 will now be described. Many different error detection/correction codes can be used in the present invention. For example, the odd-weight Hamming code discussed in U.S. Pat. No. 5,638,385, entitled “Fast Check Bit Write For a Semiconductor Memory” by John A. Fifield et al, and “Cost Analysis of On Chip Error Control Coding for Fault Tolerant Dynamic RAMs,” by N. Jarwala et al, Proceedings of the Seventeenth International Symposium on Fault-Tolerant Computing, Pittsburgh, Pa., Jul. 6–8, 1987, pp. 278–283 can be used in one embodiment. In the described embodiment, the odd-weight Hamming Code discussed in “16-bit CMOS Error Detection And Correction Unit”, Integrated Device Technology, Inc. Data Book, April 1990, Section 5.10, pp. 1–19 is used. The 72-bit modified Hamming Code provides single-bit error correction and double-bit error detection. The 72-bit code includes 64 data bits, and 8 check bits.
Implementation of error detection/correction using odd-weight Hamming code has been described in references including U.S. Pat. No. 5,638,385, entitled “Fast Check Bit Write For A Semiconductor Memory” by John A. Fifield et al., and “A Class Of Optimal Minimum Odd-Weight-Column SEC-DED Codes”, by M. Y. Hsiao, IBM Journal of Research and Dev., Vol. 14, July, 1970, pp. 395–401. In a preferred embodiment, error detection/correction unit 106 uses mainly combinational logic. For syndrome generation, 3 levels of 4-input and 3-input exclusive OR gates can be used. For syndrome decoding, 5-input AND gates can be used. This kind of implementation using combinational logic is well known to the art of logic design and therefore is not described further.
Error detection/correction unit 106 includes check bit generator 111 , syndrome generator and decoder 112 , and error correction unit 113 . During a read access, the odd-weight Hamming code is read from memory array 101 and driven on memory data bus MD[ 71 : 0 ]. Within error detection/correction unit, the memory bus is split into two fields: the read data word field RD[ 63 : 0 ] and the read check bit field RCB[ 7 : 0 ]. The read data word RD[ 63 : 0 ] is input to check bit-generator 111 . The check-bit generator 111 , similar to ECC generator 202 ( FIG. 2 ), generates an 8-bit ECC check bit value in response to read data word RD[ 63 : 0 ]. This ECC check bit value is provided to syndrome generator and decoder 112 . Syndrome generator and decoder 112 bit-wise compares (exclusive OR's) the read check bits RCB[ 7 : 0 ] with the ECC check bit value provided by check bit generator 111 . The resultant 8-bit syndrome word is decoded to determine whether the 72-bit code read from the memory array is free of error, contains a single-bit error, or contains multiple-bit errors. In the case of a single-bit error, syndrome generator and decoder 112 generates an 8-bit signal identifying the location of the error bit from the syndrome, and activates a single-error identifier signal (1-ERR) to a logic high state. The 8-bit syndrome signal identifying the location of the error bit is transmitted to error correction unit 113 . In response, error correction unit 113 corrects the error bit, which may exist in either the read data word RD[ 63 : 0 ] or the ECC check bit value RCB[ 7 : 0 ]. If no error is detected, the read data word RD[ 63 : 0 ] and ECC check bit value RCB[ 7 : 0 ] are not modified. In the case of multiple bit error, neither the read data word RD[ 63 : 0 ] nor the ECC check bit value RCB[ 7 : 0 ] is modified.
The read data value provided by error correction unit 113 is labeled as corrected data value CD[ 63 : 0 ] (even though it is understood that error correction unit 113 may not make any corrections to the read data value). Similarly, the ECC check bit value provided by error correction unit is designated as corrected ECC check bit value CCB[ 7 : 0 ]. The corrected data value CD[ 63 : 0 ] is driven through output driver 108 to the output data bus Do[ 63 : 0 ]. Both the corrected data value CD[ 63 : 0 ] and the corrected ECC check bit value CCB[ 7 : 0 ] are also driven to write-back buffer 107 . If the single-error indicator signal 1-ERR is asserted high, the corrected data value CD[ 63 : 0 ], the corrected ECC check bit value CCB[ 7 : 0 ], and the corresponding latched address LA[ 14 : 0 ] associated with the read access are all written to write-back buffer 107 . As described in more detail below, the corrected data value CD[ 63 : 0 ] and the corrected ECC check bit value CCB[ 7 : 0 ] are queued in write-back buffer 107 , in anticipation of a write-back operation to memory array 101 .
Write-Back Buffer
FIG. 3 is a circuit diagram illustrating write-back buffer 107 in accordance with one embodiment of the present invention. In this embodiment, write-back buffer 107 includes registers 300 – 301 , D-type flip-flops 310 – 311 , toggle flip-flops 312 – 313 , AND gates 321 – 326 , NAND gate 327 , OR gates 330 – 332 , NOR gate 333 , output multiplexers 341 – 343 and tri-state output drivers 351 – 352 . Registers 300 – 301 provide storage for 2 entries, wherein each entry includes an address field (ADDR), a data field (DATA) a correction check bit field (CCB) and a valid bit field (VALID). The valid bit field, when set to a logic ‘1’ value, indicates that the contents of the corresponding register are valid and should be written-back to memory array 101 . Registers 300 and 301 are arranged in a FIFO configuration in the described embodiment.
The address fields of registers 300 and 301 are coupled to receive the latched address signal LA[ 14 : 0 ], the data fields of registers 300 and 301 are coupled to receive the corrected data value CD[ 63 : 0 ], and the correction check bit fields of registers 300 and 301 are coupled to receive the corrected check bits CCB[ 7 : 0 ]. The address, data, correction bit and valid fields of register 300 are labeled LA 0 , CD 0 , CCB 0 and VA 0 , respectively. The address, data, corrected check bit and valid fields of register 301 are labeled LA 1 , CD 1 , CCB 1 and VA 1 , respectively. Corrected check bit values CCB 0 and CCB 1 stored in registers 300 and 301 are provided to multiplexer 341 . Corrected data values CD 0 and CD 1 stored in registers 300 and 301 are provided to multiplexer 342 . Latched address values LA 0 and LA 1 stored in registers 300 and 301 are provided to multiplexer 343 .
Multiplexers 341 – 343 are controlled by the Q output of toggle flip-flop 313 , which operates as a read pointer value, RP. If the read pointer value RP provided by flip-flop 313 has a logic “0” value, then multiplexers 341 , 342 and 343 route the CCB 0 , CD 0 and LA 0 values, respectively. Conversely, if the read pointer value RP has a logic “1” value, then multiplexers 341 , 342 and 343 route the CCB 1 , CD 1 and LA 1 values, respectively.
The outputs of multiplexers 341 and 342 are routed to tri-state output drivers 351 and 352 , respectively. Tri-state drivers 351 and 352 are controlled by the output enable signal OE provided at the Q output terminal of flip-flop 311 . When enabled, tri-state buffers 351 and 352 drive the signals received from multiplexers 341 and 342 as memory data output signals MD[ 71 : 64 ] and MD[ 63 : 0 ], respectively. The output of multiplexer 343 is directly provided as write-back buffer tag address WBBTag[ 14 : 0 ].
In general, write-back buffer 107 operates as follows. When a single error is detected by error detection/correction unit 106 during a read operation, the corrected data value, the corrected check bit value and the associated address value are written to one of registers 300 - 301 in write-back buffer 107 . During a subsequent idle cycle, the corrected data value and corrected check bit value are written back to memory array 101 at the location specified by the associated address value.
The operation of write-back buffer 107 will now be described in more detail. To initialize write-back buffer 107 , the RESET signal is initially asserted high. In response, OR gates 330 and 331 provide logic high reset values R 0 and R 1 to registers 300 and 301 , respectively. These logic high reset values R 0 and R 1 asynchronously reset the VALID bit fields of registers 300 and 301 to logic “0” values (i.e., VA 0 =VA 1 =“0”). The logic “0” VALID bits VA 0 and VA 1 cause OR gate 332 to provide a logic “0” output signal to AND gate 326 , thereby forcing the write-back buffer retire signal WBBRet to a logic “0” value. The logic “0” WBBRet signal is latched into flip-flop 311 , such that the output enable signal OE initially has a logic “0” value, thereby disabling tri-state output drivers 351 – 352 . When the WBBRet signal has a logic “0” value, no corrected data values are written back to memory array 101 . The logic “0” WBBRet signal is also applied to AND gates 324 and 325 . As a result, the WBBRet signal causes the reset values R 0 and R 1 provided by OR gates 330 and 331 to initially remain at logic “0” values after the RESET signal transitions to a logic “0” value.
The logic high RESET signal also sets the read pointer value RP provided by toggle flip-flop 313 to a logic “1” value, such that multiplexers 341 – 343 are initially set to pass the CCB 1 , CD 1 and LA 1 values, respectively, from register 301 .
The logic high RESET signal also resets the Q output of toggle flip-flop 312 to a logic “0” value. The Q output of toggle flip-flop 312 operates as a write pointer value WP. When the write pointer value WP is low, register 300 is designated to receive the corrected check bit value CCB[ 7 : 0 ], the corrected data value CD[ 63 : 0 ], and the latched address value LA[ 14 : 0 ]. Conversely, when the write pointer value WP is high, register 301 is designated to receive these values CCB[ 7 : 0 ], CD[ 63 : 0 ] and LA[ 14 : 0 ]. More specifically, when the write pointer value WP is low, AND gate 322 is enabled to pass the write buffer enable signal WBEN to the enable input terminal of register 300 as the load signal LD 0 . When the write pointer value WP is high, AND gate 323 is enabled to pass the write buffer enable signal WBEN to the enable input terminal of register 301 as the load signal LD 1 .
The write buffer enable signal WBEN is provided by AND gate 321 . AND gate 321 is coupled to receive the 1-ERR signal from error detection-correction circuit 106 . AND gate 321 is also coupled to receive a latched read enable signal LREN provided at the Q output of flip-flop 310 . (The read enable signal REN is latched into flip-flop 310 in response to the CLK signal to provide the latched read enable signal LREN). AND gate 321 is also coupled to receive the output of NAND gate 327 , which has input terminals coupled to receive valid bits VA 0 and VA 1 . Thus, the write buffer enable signal WBEN signal will be asserted high if there is a single error detected in a read data value (1-ERR=“1”) during a read operation (LREN=“1”) and there is an available entry in one of registers 300 and 301 (VA 0 and VA 1 not=“11”).
The first time that there is a single error detected during a read operation, the write buffer enable signal WBEN is asserted high. In response to the high WBEN signal and the low write pointer value WP, AND gate 322 asserts a logic high load signal LD 0 , which enables register 300 . In response, the CCB[ 7 : 0 ], CD[ 63 : 0 ] and LA[ 14 : 0 ] values provided during the read operation are latched into register 300 . In addition, the logic high LD 0 signal is latched into the VALID field of register 300 , thereby setting valid bit VA 0 to a logic high state.
The logic high valid bit VA 0 causes OR gate 332 to provide a logic high signal to AND gate 326 . During a subsequent idle cycle when there are no pending read or write accesses (i.e., REN=WEN=“0”), AND gate 326 will receive a logic high signal from NOR gate 333 . Under these conditions, the write-back buffer retire signal WBBRet is asserted high, thereby indicating that the contents of register 300 can be retired to memory array 101 , without interfering with a read or write operation. On the next rising edge of the CLK signal, the logic high WBBret signal toggles the read pointer value RP provided by flip-flop 313 to a logic “0” value, and causes the output enable signal OE of flip-flop 311 to transition to a logic “1” value. At this time, multiplexers 341 – 343 route the CCB 0 , CD 0 and LA 0 signals from register 300 . Tri-state buffers 351 and 352 are enabled to drive the CCB 0 and CD 0 values from register 300 as the MD[ 71 : 64 ] and MD[ 63 : 0 ] values in response to the logic high output enable signal OE. The latched address value LA 0 from register 300 is provided to memory array 101 as the write back buffer tag address WBBTag[ 14 : 0 ]. Note that the WBBTag[ 14 : 0 ] signal is routed through address multiplexer 104 in response to the logic low REN and WEN signals.
The logic high WBBRet signal is also provided to memory array sequencer 102 , thereby initiating the generation of the memory control signals (RAS#, SEN#, CAS#, PRC#) required to write the corrected data back to memory array 101 . At this time, the corrected data value CD 0 and corrected check bit value CCB 0 are written back to memory array 101 at the location identified by address value LA 0 .
The CLK signal subsequently transitions to a logic low level. At this time, the logic low CLK signal, the logic high WBBRet signal and the logic low read pointer value RP cause AND gate 324 to provide a logic high output signal. In response, OR gate 330 asserts a logic high reset signal R 0 , which resets the valid bit VA 0 in register 300 to a logic “0” value. The logic low VA 0 bit causes the WBBRet signal to transition to a logic low value.
As described above, the entry stored in register 300 is retired during an idle cycle (i.e., WEN=REN=“0”). However, as long as consecutive read or write operations occur, there will be no idle cycle during which the entry in register 300 can be retired. In this case, this entry remains in register 300 .
If another read operation (REN=“1”) having a single error (1-ERR=“1”) occurs before the next idle cycle, AND gate 321 will again assert the write buffer enable signal WBEN to a logic “1” value. The logic “1” value of the WBEN signal causes flip flop 312 to toggle, such that the write pointer value WP is changed to a logic “1” value. This logic high WP signal causes AND gate 323 to assert a logic high load signal LD 1 . In response, the CCB[ 7 : 0 ], CD[ 63 : 0 ] and LA[ 14 : 0 ] signals associated with the current read operation are loaded into register 301 as values CCB 1 , CD 1 and LA 1 , respectively. The logic high load signal LD 1 is also loaded into the VALID field of register 301 , such that valid bit VA 1 has a logic high value.
At this time, both of the valid bits VA 0 and VA 1 have logic “1” values. As a result, NAND gate 327 provides a logic “0” value to AND gate 321 . Consequently, the write buffer enable signal WBEN cannot be asserted until at least one of the valid bits VA 0 and VA 1 transitions to a logic “0” value. That is, no additional entries can be written to write-back buffer 107 until the entry stored in register 300 has been retired to memory array 101 . Note that if a single error condition exists during a subsequent read operation (before the entry in register 300 can be retired), then the corresponding corrected data value/check bits will not be written back to memory array 101 . However, the corrected data value will be read out of memory device 100 . Thus, failure to write-back the corrected value does not result in failure of memory device 100 . It is likely that the next time that this data value/check bit is read from memory array 101 , space will be available in write-back buffer 107 , such that the corrected data value/check bit can be properly written back to memory array 101 .
Specific examples of write, read and write-back operations will now be described.
Write Access Timing
FIG. 4 is a waveform diagram illustrating the timing of two write accesses in accordance with one embodiment of the present invention. Prior to the rising edge of clock cycle T 1 , the write enable signal WEN is asserted high, a first write data value D 0 is provided on input data bus Di[ 63 : 0 ], and a first write address value A 0 is provided on address bus A[ 14 : 0 ]. At the rising edge of clock cycle T 1 , the first write data value D 0 and the first write address A 0 are latched into register 200 . In FIG. 4 , the write data value stored in register 200 is designated as DATA 200 and the address value stored in register 200 is designated as ADDR 200 . During cycle T 1 , ECC generator 202 generates an ECC check bit value, CB 0 , in response to the first write data value D 0 stored in register 200 . Note that memory array sequencer 102 asserts the memory control signals RAS#, SEN#, CAS# and PRC# during the first clock cycle T 1 in response to the logic high write enable signal WEN. However, this write access is ignored in the present example for reasons of clarity.
No write access is performed during clock cycle T 2 (i.e., the WEN signal is low). As a result, the first write data value D 0 and the first write address A 0 remain latched in register 200 during cycle T 2 .
Prior to the rising edge of clock cycle T 3 , the write enable signal WEN is asserted high, a second write data value D 1 is provided on input data bus Di[ 63 : 0 ], and a second write address value A 1 is provided on address bus A[ 14 : 0 ]. At the rising edge of clock cycle T 3 , the first write data value D 0 , the first write address A 0 and the first ECC check bit value CB 0 are latched into register 201 . In FIG. 4 , the write data value stored in register 201 is designated as DATA 201 , the address value stored in register 201 is designated as ADDR 201 , and the ECC check bit value stored in register 201 is designated as CB 201 . Also at the rising edge of clock cycle T 3 , the second write data value D 1 and the second write address value A 1 are latched into register 200 . During cycle T 3 , ECC generator 202 generates an ECC check bit value, CB 1 , in response to the second write data value D 1 stored in register 200 .
The logic high write enable signal WEN enables output buffers 210 and 211 , such that these output buffers drive the first data value D 0 and the first ECC check bit value CB 0 from register 201 onto memory data bus MD[ 71 : 0 ]. The first write address A 0 is provided from register 201 as the write buffer tag signal WBTag[ 14 : 0 ]. This write buffer tag signal WBTag[ 14 : 0 ] is routed through multiplexer 104 to memory array 101 in response to the logic high write enable signal. Memory array sequencer, asserts the memory write signal Mwrite and the memory control signals RAS#, SEN#, CAS# and PRC# in response to the logic high write enable signal WEN during cycle T 3 , thereby enabling the first write data value D 0 and the first ECC check bit value CB 0 to be written to memory array 101 at the location specified by the first write address A 0 . Note that the second write data value D 1 and the second write address A 1 remain in register 200 until the next write access (or the next read access that hits write buffer 105 ). Also note that ECC check bit value CB 1 are waiting at the output of ECC generator 202 until the beginning of the next write access. In this manner, the generation of ECC check bit values doe not affect the write access latency of memory device 100 .
Single Read Access and Write-Back Timing
FIG. 5 is a waveform diagram illustrating the timing of a read transaction followed by a write-back operation in accordance with one embodiment of the present invention. Before the rising edge of clock cycle T 1 , the read enable signal REN is asserted high and a read address Ax[ 14 : 0 ] is provided on address bus A[ 14 : 0 ] to initiate a read access. At the rising edge of cycle T 1 , the read address Ax[ 14 : 0 ] is latched into address register 103 as the latched read address LAx[ 14 : 0 ]. This latched read address LAx[ 14 : 0 ] is driven to the memory address bus MA[ 14 : 0 ] through multiplexer 104 . Multiplexer 104 routes the latched read access address LAx[ 14 : 0 ] in response to the high state of read enable signal REN and the low state of the write enable signal WEN.
The logic high read enable signal REN is also latched into memory array sequencer 102 in response to the rising edge of cycle T 1 . In response, memory array sequencer 102 sequentially activates the memory array control signals RAS#, SEN#, CAS#, and PRC#, thereby reading the Hamming code word (i.e., MDx[ 71 : 0 ]) associated with the latched read address LAx[ 14 : 0 ]. Note that the only memory array control signal shown in FIG. 5 is the CAS# signal. The high state of the latched read enable signal REN in memory array sequencer 102 causes the memory write signal MWrite have a logic low value, thereby indicating that the present memory operation is a read access. Consequently, the accessed word MDx[ 71 : 0 ] is read out from the memory array on data bus MD[ 71 : 0 ].
The 72-bit accessed word MDx[ 71 : 0 ] is provided to error detection-correction unit 106 , wherein the data portion of the word (i.e., MDx[ 63 : 0 ]) and the check-bit portion of the word (i.e., MDx[ 71 : 64 ]) are separated for syndrome generation, error detection and correction. If a single-bit error is detected, syndrome generator 112 activates the single-error signal (1-ERR) high, and error correction unit 113 corrects the single-bit error in either the data word or the check-bits. The corrected data word CDx[ 63 : 0 ] is driven through output driver 108 as the output data value Do[ 63 : 0 ].
Within write-back buffer 107 , flip-flop 310 latches the logic high read enable signal REN at the rising edge of cycle T 1 , thereby providing a logic high latched read enable signal LREN. When the single error signal 1-ERR is activated high by syndrome generator 112 , AND gate 321 activates the write buffer enable signal WBEN to a logic high state. AND gate 322 activates the load data signal LD 0 to a logic high value in response to the logic high WBEN signal and the logic low write pointer value WP. At the beginning of clock cycle T 2 , the CLK signal transitions to a logic high state, thereby activating register 300 , such that the logic high LD 0 signal, the corrected check bits CCBx[ 7 : 0 ], the corrected data word CDx[ 63 : 0 ] and the associated latched address LAx[ 14 : 0 ] are written to register 300 of write-back buffer 107 . At the this time, the valid bit VA 0 transitions to a logic high state, and the corrected ECC code word, consisting of corrected check bits CCBx[ 7 : 0 ] and the corrected data word CDx[ 63 : 0 ], is available at the output of register 300 .
At the beginning of cycle T 2 , both the read enable signal REN and the write enable signal WEN are low, thereby indicating the absence of an external access. However, the valid signal VA 0 goes high after the rising edge of clock cycle T 2 . As a result, WBBRet signal has a low state at the rising edge of cycle T 2 . Thus, even though no external access is requested during cycle T 2 , write-back does not take place during cycle T 2 .
At the beginning of cycle T 3 , the high state of the WBBRet signal toggles the output of toggle flip-flop 313 (i.e., read pointer value RP) from high to low. The low state of the read pointer signal RP causes multiplexers 341 – 343 to route the corresponding contents of register 300 . As a result, the latched address value LAx[ 14 : 0 ] stored in register 300 is driven as the write-back buffer tag address WBBTagx[ 14 : 0 ]. The WBBTagx[ 14 : 0 ] signal is provided to multiplexer 104 . Multiplexer 104 routes the WBBTagx[ 14 : 0 ] signal as the memory address signal MA[ 14 : 0 ] in response to the logic low states of the REN and WEN signals. Multiplexers 341 and 342 route the corrected check bit value CCBx[ 7 : 0 ] and the corrected data word CDx[ 63 : 0 ] to tri-state buffers 351 and 352 , respectively. The output enable signal OE is asserted high when the high state of the WBBRet signal is latched into flip-flop 311 at the rising edge of cycle T 3 . The high OE signal enables tri-state buffers 341 and 342 to drive the corrected check bit value CCBx[ 7 : 0 ] and the corrected data word CDx[ 63 : 0 ] onto memory data bus MD[ 71 : 0 ].
Memory array sequencer 102 latches the logic high WBBRet signal at the rising edge of cycle T 3 , thereby resulting in the sequential activation of the memory control signals RAS#, SEN#, CAS# and PRC#. Memory array sequencer 102 also asserts the MWrite signal in response to the logic high WBBRet signal. As a result, the word on data bus MD[ 71 : 0 ] is written to the memory location specified by the address WBBTag[ 14 : 0 ]. At the falling edge of the CLK signal in cycle T 3 , AND gate 324 provides a logic high output signal, thereby driving the reset signal R 0 to a logic high state. The logic high reset signal R 0 resets the valid bit VA 0 to a logic low value. The logic low valid bits VA 0 and VA 1 cause OR gate 333 to provide a logic “0” output signal, which in turn, causes the WBBRet signal to transition to a logic “0” state. At the end of CLK cycle T 3 , the control signals RAS#, SEN#, CAS# and PRC# are de-asserted high, thereby completing the memory write operation and write-back cycle.
Notice that if a single-bit error does not occur in the read access of cycle T 1 , then neither the data nor the check bits read from memory array 101 will be corrected or stored in write-back buffer 107 . However, the uncorrected data is still driven out to the output data bus Do[ 63 : 0 ] by output driver 108 .
Back-to-Back Read Cycles and Write-Back Cycles
FIG. 6 is a waveform diagram illustrating the timing of two consecutive read access cycles followed by two consecutive write-back cycles in accordance with one embodiment of the present invention. Before the rising edge of clock cycle T 1 , the read enable signal REN is asserted high and a read address A 1 [ 14 : 0 ] is provided on address bus A[ 14 : 0 ] to initiate a read access. The read cycle operations and the control timing waveforms are similar to those shown in FIG. 5 . A single-bit error is detected in this first read access, which results in the corrected Hamming code word (CD 1 /CCB 1 ) and address A 1 [ 14 : 0 ] being stored in register 300 of write-back buffer 107 . At the rising edge of cycle T 2 , the high state of the 1-ERR and LREN signals causes toggle flip-flop 312 to change the write pointer value WP from a logic “0” value to a logic “1” value, thereby configuring register 301 of write-back buffer 107 to receive the next corrected Hamming code word and address.
Before the rising edge of clock cycle T 2 , another read enable signal REN is asserted high and a second read address A 2 [ 14 : 0 ] is provided on address bus A[ 14 : 0 ] to initiate a second read access. Again, the read cycle operations and the control timing waveforms are similar to those shown in FIG. 5 . A single-bit error is detected in this second read access. In response, error detection-correction circuit 106 asserts the 1-ERR signal and provides a corrected Hamming code word that includes corrected data CD[ 63 : 0 ] and corrected check bit CCB 2 [ 7 : 0 ]. In response to the logic high 1-ERR signal, the logic high LREN signal, and the logic high output of NAND gate 327 , AND gate 321 provides a logic high write buffer enable signal WBEN. In response to the logic high WBEN signal and the logic “1” write pointer value, AND gate 323 asserts the load signal LD 1 to a logic high value, thereby enabling register 301 . On the rising edge of cycle T 3 , the corrected Hamming code word (CD 2 /CCB 2 ), address A 2 [ 14 : 0 ] and the high state of LD 1 are latched into register 301 of write-back buffer 107 . Consequently, valid bit VA 1 is driven to a logic high value.
At the end of cycle T 2 , the low states of the REN and WEN signals indicate the absence of an external memory access. The low states of the REN and WEN signals, along with the high state of the VA 0 signal causes AND gate 326 to assert a logic high WBBRet signal. In write-back buffer 107 , this high WBBRet signal is latched into flip-flop 311 at the rising edge of cycle T 3 , thereby causing output enable signal OE to go high. The high state of the WBBRet signal at the rising clock-edge also causes toggle flip-flop 313 to drive the read pointer value RP to a logic “0” state. Consequently, first address A 1 [ 14 : 0 ] stored in register 300 is driven as the output signal WBBTag[ 14 : 0 ], while the corrected data and check bits CD 1 [ 63 : 0 ] and CCB 1 [ 7 : 0 ] stored in register 300 are driven as output signal MD[ 71 : 0 ]. The write-back buffer tag WBBTag[ 14 : 0 ] is provided to memory array 101 through multiplexer 104 in response to the logic low REN and WEN signals. In memory array sequencer 102 , the high state of the WBBRet signal is latched at the beginning of cycle T 3 . Subsequently, the MWrite signal is driven high and the memory array control signals RAS#, SEN#, CAS# and PRC# are activated in sequence so that memory array 101 goes through a memory write cycle with the corrected code word MD[ 71 : 0 ] written to the location specified by WBBTag[ 14 : 0 ]. The reset signal R 0 goes high in response to the falling edge of cycle T 3 , thereby resetting the valid bit VA 0 in register 300 . Resetting valid bit VA 0 invalidates the contents of register 300 . At the end of cycle T 3 , the memory array control signals are all deactivated high and memory array 101 is ready for another access.
At the end of cycle T 3 , the low states of the REN and WEN signals again indicate the absence of an external memory access. The low states of the REN and WEN signals, together with the high state of valid bit VA 1 causes the WBBRet signal to remain in a logic high state. At the beginning of cycle T 4 , the high state of the WBBRet signal causes the read pointer value RP provided by toggle flip-flop 313 to transition to a logic high state. As a result, multiplexers 341 – 343 are controlled to route the corrected check bit CCB 2 [ 7 : 0 ] and the corrected data value CD 2 [ 63 : 0 ] as the MD[ 71 : 0 ] value, and the address value A 2 [ 14 : 0 ] as the write back buffer tag value WBBTag[ 14 : 0 ]. Note that the output enable signal OE remains in a logic high state in response to the logic high WBBRet signal. In memory array sequencer 102 , the high state of the WBBRet signal is latched at the rising edge of cycle T 4 . The high state of the WBBRet signal causes the MWrite signal to remain high, thereby starting another write cycle in memory array 101 . The write cycle is performed with the successive activation of the RAS#, SEN#, CAS# and PRC# signals. This results in the modified Hamming code word MD[ 71 : 0 ] from register 301 being written back to memory array 101 at the location (A 2 ) specified by the WBBTag[ 14 : 0 ] read from register 301 . The reset signal R 1 goes high in response to the falling edge of cycle T 4 , thereby resetting the valid bit VA 1 in register 301 . Resetting valid bit VA 1 invalidates the contents of register 301 . At the end of cycle T 4 , the memory array control signals are all deactivated high and memory array 101 is ready for another access. When the valid bit VA 1 transitions to a logic low state, both of valid bits VA 0 and VA 1 have logic low values. As a result, OR gate 332 provides a logic low output signal, which causes the WBBRet signal to transition to a logic low state. The logic low valid bits VA 0 and VA 1 indicate that both entries of write-back buffer 107 have been retired to memory array 101 .
Note that if another read access occurs during cycle T 3 with a single-bit error on the accessed code word, then the corrected code word will not be written in the write-back buffer, because both of the valid bits VA 0 and VA 1 are high. The high valid bits VA 0 and VA 1 cause the output of NAND gate 327 to go low, and the output of AND gate (i.e., write-back enable signal WBEN) to go low. The low state of the WBEN signal prevents the load signals LD 0 and LD 1 from being asserted, and thereby prohibits writing new entries to registers 300 and 301 . Rather, the entries in registers 300 and 301 are preserved for subsequent write-back operations. The corrected code resulted from this third read access is not written back to the memory array 101 . However, this does not result in memory failure as long as the memory word does not accumulate another error bit, because this code word can still be read and corrected during a subsequent read access.
Although the invention has been described in connection with several embodiments, it is understood that this invention is not limited to the embodiments disclosed, but is capable of various modifications, which would be apparent to a person skilled in the art. For example, although the described embodiments have focused on a memory array using DRAM cells, it is understood that a memory array using SRAM cells or non-volatile memory cells can be implemented in other embodiments with some modification to the memory array sequencer. Such modification could be readily accomplished by one of ordinary skill in the art of memory design. Thus, the invention is limited only by the following claims.
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A memory device that uses error correction code (ECC) circuitry to improve the reliability of the memory device in view of single-bit errors caused by hard failure or soft error. A write buffer is used to post write data, so that ECC generation and memory write array operation can be carried out in parallel. As a result there is no penalty in write latency or memory cycle time due to ECC generation. A write-back buffer is used to post corrected ECC words during read operations, so that write-back of corrected ECC words does not need to take place during the same cycle that data is read. Instead, write-back operations are performed during idle cycles when no external memory access is requested, such that the write back operation does not impose a penalty on memory cycle time or affect memory access latency.
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TECHNICAL FIELD
The present invention relates to scroll-type fluid compressors, and in particular to a scroll-type fluid compressor external shaft bearing assembly.
BACKGROUND OF THE INVENTION
Scroll-type fluid compressors are well known in the prior art. U.S. Pat. No. 4,432,708 issued to Hiraga et al discloses an apparatus including two scrolls, each having a circular end plate and a spiral element disposed on each plate. The scrolls are radially offset such that both spiral elements cooperate to make a plurality of contacts between their spiral curved surfaces.
In operation, one of the scrolls is subjected to an orbital motion and the line contacts shift, resulting in a change in the volume of the fluid pockets contained within the scrolls. This change in volume of the fluid pockets is utilized to compress fluids, for example air conditioning fluids needed for operation of the air conditioning system of automobiles.
Prior art compressors such as disclosed in U.S. Pat. No. 4,604,039 to Terauchi and U.S. Pat. No. 4,890,987 to Sato et al include a main drive shaft supported by a main drive shaft bearing. The main drive shaft bearing is comprised of a bearing race and two spaced sets of bearings surrounding the circumference of the main drive shaft. The nose portion of the front cover of the compressor extends around and encloses the outer periphery of the main bearings. A clutch bearing is disposed directly on the outer diameter of the nose portion of the compressor.
The clutch bearing supports the clutch assembly used to induce and control the rotational motion needed to operate the compressor. The compressors disclosed in the Terauchi patent and the Sato et al patent are representative of prior art designs utilizing a dual bearing assembly for rotatably supporting both the main drive shaft and the clutch assembly. Both designs disclose a nose portion located intermediate the clutch bearing and the main drive shaft bearing. It is known in the art that this nose portion is difficult and relatively expensive to machine to rigid dimensional specifications. The precision machining of the nose portion adds expense to the manufacture of the overall compressor.
The main drive shaft bearing and outer pulley bearing in combination with the nose portion of the front cover also create an axial "stack up" of dimensional tolerances. This axial "stack-up" is the cumulative addition of dimensional tolerances of adjacent parts. This cumulative addition causes premature failure of the compressor components and drive belts.
The clutch assembly includes a rotor which rests on the clutch bearing and cooperates with an engagement hub assembly to comprise the main clutch assembly components needed for the compressor's operation. In use, when air conditioning is required inside the automobile the clutch assembly is energized by a switch in the passenger compartment. The clutch assembly is energized and an electromagnet in the clutch assembly creates a magnetic field pulling the engagement hub assembly toward the rotor. The engagement hub assembly and rotor engage and induce rotational movement in the main drive shaft. Eccentric mounting of a drive pin on a disc rotor associated with the main drive shaft induces orbital motion in the scroll., When the air conditioning system is not operating, the engagement hub assembly and rotor are not engaged and the rotor rotates independently from the engagement hub assembly.
Generally, wear occurs between the engagement hub assembly and rotor due to normal operating contact between the engagement hub assembly and rotor. If axial "stack ups" between the main bearing, nose portion and clutch bearing reach a high level, premature wear of the engagement hub assembly, rotor and other compressor components occurs. Axial stack-up also contributes to drive belt misalignment which greatly increases drive belt wear. If axial "stack-up" reaches a critical level, clutch engagement will not occur.
Precise relative positioning of interfacing components is a prerequisite to an acceptable compressor design. Relative parallel positioning or "squareness" as it is sometimes termed is essential for operation of the engagement hub assembly and rotor in the clutch assembly. Axial tolerance "stack up" alters the desired positional relationships and may cause premature wear because of contact between misaligned components. Specifically, any misalignment of the engagement hub assembly and rotor forces one portion of the engagement hub assembly to contact the rotor before the other portion, creating premature wear areas that lead to component failure. This condition decreases the overall life of the engagement hub assembly and rotor and consequently the overall life of the air conditioning compressor in general. Misalignment of the engagement hub assembly and rotor also heightens noise levels and vibration created by the clutch assembly during engagement.
The bearing assembly disclosed in U.S. Pat. No. 4,673,340 to Mabe et al patent depicts a main drive shaft bearing utilizing only one bearing assembly. The pulley bearing disclosed is similar to those disclosed in the Sato et al patent and the Terauchi patent. Again, a machined nose portion extends between the main drive shaft bearing and the pulley bearing. U.S. Pat. No. 4,432,708 to Hiraga et al discussed above discloses yet a third type of bearing assembly. A first bearing is used to support the main drive shaft. This bearing is located on an oversized journal disposed adjacent, but not between, the outer pulley bearing. The design of the nose portion requires machining of both inner and outer dimensions to fit and support the bearing assembly in operation.
SUMMARY OF THE INVENTION
The present invention is directed to a scroll-type fluid compressor bearing assembly. The bearing assembly includes a first main drive shaft bearing used for supporting the main drive shaft of the scroll compressor. A clutch assembly bearing is utilized to support the clutch/pulley mechanism needed to induce orbital motion for operation of the compressor. In the present invention the clutch assembly bearing includes an inner journal configured such that the clutch assembly can be mounted directly on the main drive shaft bearing. Thus, the clutch assembly bearing operates as an outer housing for the main drive shaft bearing.
It is an object of the present invention to provide a scroll-type compressor bearing assembly which reduces axial tolerance "stack ups" between the main drive shaft bearing and clutch assembly bearing.
It is another object of the present invention to provide a scroll-type compressor bearing assembly that allows for the use of a larger bearing which is less expensive than smaller bearing.
It is a further object of the present invention to provide a scroll-type bearing assembly where the clutch assembly bearing mounts directly upon the main drive shaft bearing and acts as a housing for such.
It is still a further object of the present invention to provide a scroll-type bearing assembly which reduces the machining requirements for the housings used to surround the inner components of scroll-type bearing compressors.
It is still yet another further object of the present invention to provide a scroll-type bearing assembly that provides for increased durability of compressor components and an increased drive belt life due to reduction in axial tolerance "stack ups" in the bearing assembly.
Further objects, features and other aspects of this invention will be understood from the detailed description of the preferred embodiment of this invention with reference to the attached drawings.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded, partial perspective view of a clutch assembly and main drive assembly of a scroll-type compressor utilizing the bearing assembly of the present invention; an
FIG. 2 is a partial cross-sectional view of the bearing assembly of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the attached drawings, in FIG. 1 there is shown generally the front assembly portion of a scroll type air compressor 10, with a front cover 12 and an extending nose member 14. Extending nose member 14 has a bearing contact surface 16. Main drive shaft 18 has a journal surface 20 for accepting main drive shaft bearing 22. Main drive shaft 18 is rotatably supported by main drive shaft bearing 22. A fastener groove 24 extends around the outer circumference of main drive shaft bearing 22. Clutch bearing 26 has an inner journal 29 configured such that main drive shaft bearing 22 is disposed and housed within inner journal 29. A snap ring 30 is affixed within fastener groove 24 on main drive shaft bearing 22. Snap ring 30 locates main drive shaft bearing 22 to the clutch assembly bearing 26. In addition, snap ring 30 further retains main drive shaft bearing 22 and clutch bearing 26 against bearing contact surface 16. Engagement hub assembly 40 has a contact surface 41. Contact surface 41 acts to further secure clutch assembly bearing 26 onto nose member 14.
Electromagnetic coil 28 is mounted onto nose portion 14 and locates inside clutch assembly rotor 32. Main drive shaft 18 includes an connecting portion 34 and a threaded portion 36. Connecting portion 34 extends through clutch assembly rotor 32 and connects to clutch assembly engagement hub assembly 38. Connecting portion 34 of main drive shaft 18 cooperates with a mating portion 38 within clutch assembly engagement hub assembly 40. Clutch assembly pulley 42 is affixed to or an integral part of rotor 32. As shown in FIG. 1, a washer 43 and a nut 44 attach the engagement hub assembly 40 to the drive shaft 22 and secure the entire bearing assembly onto the drive shaft.
In the rotating free state, that is when the air conditioning unit of the automobile is not in use, the drive belt running off the automobile engine is rotating pulley 42 which in turn rotates clutch assembly rotor 32. In the free state, the main drive shaft is not rotating and therefore the scrolls, not shown, are not orbiting and not compressing gas. If the air conditioning system of the automobile is turned on, electromagnetic coil 28 is energized and the magnetic forces induced by the electromagnetic coil bring engagement hub assembly 38 into engagement with clutch assembly rotor 32. At this time, the rotational movement of the rotor induced by the drive belt rotates main drive shaft 18. This rotational movement is translated into orbital movement by various components not shown to operate the inner scrolls for compressing gas.
As shown in FIG. 2, clutch assembly bearing 26 encompasses and houses main drive shaft bearing 22. FIG. 2 shows one embodiment of the present invention where the main drive shaft bearing is a common race 46 and ball bearing 48 combination. A similar race 50 and ball bearing 52 form the clutch bearing 26. It is contemplated that other rolling load bearing members can be utilized with the design of the present invention, such as needle bearings or pin bearings.
In addition, because nose portion 14 does not extend between the main drive shaft bearing 22 and clutch assembly bearing 26, a larger main drive shaft bearing can be utilized with a larger inner ball bearing. As is known in the art, larger ball bearings and larger bearing races are less expensive than smaller ball bearings and smaller bearing races utilized in smaller bearing assemblies. This larger bearing also increases overall main drive shaft bearing life and thereby extends the overall life of the air conditioning compressor. The nose portion 14 of front cover 12 does not extend between the main drive shaft bearing 22 and clutch assembly bearing 24. Thus the nose portion 14 of the present invention does not require expensive machining to achieve close tolerances. In addition, dimensional tolerances associated with the machining of nose portion 14 are no longer added cumulatively with the dimensional tolerances of main drive shaft bearing 22 and clutch assembly bearing 26.
Axial tolerance "stack ups" between main drive shaft bearing 22 and clutch assembly bearing 26 are significantly reduced because of the direct contact between the two bearings. This reduction in actual tolerance "stack up" reduces detrimental squareness or misalignment conditions that occur between the engagement hub assembly and rotor. This misalignment often contributes to premature wear of the clutch assembly. Because clutch bearing 26 and main drive shaft bearing 22 are in direct contact, the overall squareness of the bearing assembly is improved.
Because actual tolerance "stack ups" are greatly reduced, premature wear of the engagement hub assembly and rotor are reduced thereby expanding the overall life of the air compressor. Specifically, a reduction in dimensional axial "stack up" produces a better alignment of the engagement hub assembly and rotor of the air compressor. A better alignment between the engagement hub assembly and rotor produces a larger surface area upon engagement of the clutch and rotor together when the electromagnetic clutch is activated. Because a larger surface area is making contacting between the engagement hub assembly and rotor upon engagement of the electromagnetic clutch, the total wear or removal of small particles from the clutch and rotor upon engagement is spread out over this larger surface area. As stated previously, when the rotor and engagement hub assembly are aligned incorrectly due to axial stack ups, a portion of the engagement hub assembly will contact the rotor first at a tangential angle. This causes wear areas that deteriorate more quickly than other surface areas contained on the engagement hub assembly. Over time this condition produces premature wear of the entire clutch assembly.
In addition to overall clutch assembly wear, axial stack-ups can produce a misalignment of the drive belt. Misalignment of the drive belt causes increased drive belt wear and shortens the useful life of the drive belt. A reduction in axial stack-up will correspondingly reduce misalignment conditions causing increased drive belt wear. This reduction in drive belt wear will reduce maintenance and replacement costs associated with air conditioning compressors used in conjunction with internal combustion engines in automobiles.
This invention has been described in detail in connection with the illustrated preferred embodiments. These embodiments, however, are merely for example only and the invention is not restricted thereto. It will be easily understood by those skilled in the art that other variations and modifications can be easily made within the scope of this invention, as defined by the appended claims.
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A scroll-type fluid compressor including a main drive shaft and a clutch assembly. The scroll-type fluid compressor including an external shaft bearing assembly comprising a main drive shaft bearing and a clutch assembly bearing. The clutch assembly bearing includes an inner journal and the main drive shaft bearing mounts directly inside the inner journal such that the clutch assembly bearing forms a housing around the main drive shaft bearing.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention pertains to the art of refrigerators and, more particularly, to a unitary face frame for a refrigerator cabinet.
[0003] 2. Discussion of the Prior Art
[0004] In constructing an appliance cabinet, particularly a refrigerator cabinet, it is highly desirable to simplify the overall assembly of the cabinet to reduce manufacturing costs, yet it is imperative that the cabinet be structurally sound in order to counteract loads exerted thereon during use of the appliance. Mainly due to cost efficiencies and flexibility in workmanship, it has been commonplace to utilize sheet metal in the forming of most refrigerator cabinets in the market today. Since sheet metal is relatively thin and rather high loads are often placed on the cabinet, particularly by the opening and closing of a weighted down refrigerator door, a fair amount of effort has been applied in this art to provide reinforcement for such a refrigerator cabinet. Of course, an additional concern is the ease of assembly of the cabinet as a whole.
[0005] With this in mind, it has heretofore been proposed to form the sides and top of a refrigerator cabinet shell out of a single piece of bent sheet metal and then attach rear and bottom walls. Thereafter, the shell is structurally reinforced in an attempt to avoid deformation during use. Such known reinforcing arrangements generally take the form of either providing multiple, individually secured reinforcement members or individual members formed into a reinforcing frame which is then positioned at a front opening of the cabinet shell. At least the sides of the shell are attached to the frame to integrate the overall assembly. To perform this assembly operation, either various holes are provided in both the cabinet shell and the reinforcement members which must be aligned to receive mechanical fasteners or systematic welding operations are performed. In either case, these connections are designed to perform the sole function of interconnecting the shell to the reinforcement structure.
[0006] Constructing and mounting the reinforcing frame has proven to be a time consuming and costly manufacturing step. Forming individual frame members, joining the frame members to form an overall frame, and mounting the frame to the cabinet shell add a considerable amount of time to the manufacturing process. Likewise, forming the frame members and then fastening the frame members to the cabinet individually is also a labor intensive process.
[0007] Based on the above, there exists a need for a simplified reinforcing frame for a refrigerator cabinet. More specifically, there exists a need for a unitary face frame that is integrally formed from a single sheet of material and then fastened to an outer cabinet shell of a refrigerator.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to a unitary face frame for a refrigerator. The refrigerator includes an outer cabinet shell having a pair of laterally spaced, upright side walls and a top wall, each of which includes a respective forward portion. First and second liners are arranged adjacent one another in the cabinet shell and define corresponding first and second refrigerated compartments.
[0009] In accordance with the invention, the face frame is integrally formed from a single material sheet and then mounted to the outer cabinet shell at the forward portion of each of the opposing side and top walls. The face frame includes top, bottom and opposing side frame members, along with a mullion member that extends between either the top and bottom frame members or the opposing side frame members, depending upon desired refrigerator configuration. The mullion member establishes first and second openings that lead into the first and second refrigerated compartments respectively.
[0010] Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of a preferred embodiment when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is an upper right perspective view of a built-in refrigerator incorporating a unitary face frame constructed in accordance with the present invention;
[0012] FIG. 2 is an exploded view of the built-in refrigerator of FIG. 1 illustrating the unitary face frame;
[0013] FIG. 3 is an elevational view of the unitary face frame shown prior to a final forming process; and
[0014] FIG. 4 is an upper right perspective rear view of the unitary face frame of FIG. 3 following the final forming process.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] With initial reference to FIG. 1 , a refrigerator constructed in accordance with the present invention is generally indicated at 2 . Refrigerator 2 is shown to include a freezer door 6 having an associated handle 7 and a fresh food door 10 having an associated handle 11 . In the embodiment shown, refrigerator 2 is of the recessed type such that, essentially, only freezer and fresh food doors 6 and 10 project forward of a wall 15 . The remainder of refrigerator 2 is recessed within wall 15 in a manner similar to a plurality of surrounding cabinets generally indicated at 18 - 23 . Refrigerator 2 also includes a plurality of peripheral trim pieces 28 - 30 . In accordance with the most preferred embodiment of the invention, trim pieces 28 - 30 are formed of aluminum. However, other materials, such as plastic, could also be utilized. Finally, it should be noted that refrigerator 2 is preferably designed with main components of a refrigeration system positioned behind an access panel 32 arranged directly above trim piece 29 as clearly shown in this figure.
[0016] Although refrigerator 2 can take various forms, FIG. 2 represents, in exploded view form, the main cabinet components of a side-by-side model for refrigerator 2 . As illustrated, refrigerator 2 includes a front frame 40 which, as will be detailed more fully below, is formed from a single sheet of material. Refrigerator 2 also includes a freezer compartment box 55 defined by interconnected side, bottom, top and back panels 57 - 61 . In a similar fashion, a fresh food compartment box 65 is formed from side, bottom, top and back panels 67 - 71 . As freezer compartment box 55 and fresh food compartment box 65 are preferably formed as separate units, they are integrated into an overall refrigerator cabinet assembly by front frame 40 and an outer shell as defined by side walls 80 and 81 , a back wall 82 which is preferably defined by four separate panels 82 a - 82 d , a bottom wall 83 , a top cover member 84 and a front cover member 85 . As will be detailed more fully below, front frame 40 is adapted to be attached to forward portions (not separately labeled) of each side wall 80 , 81 such that, front frame 40 , freezer compartment box 55 , fresh food compartment box 65 , side walls 80 and 81 , back wall 82 , bottom wall 83 , top cover member 84 and front cover member 85 are all integrated together. Also provided about openings (not separately labeled) defined by front frame 40 are associated peripheral breaker elements 90 and 91 that snap-fittingly engage with front frame 40 , freezer compartment box 55 and fresh food compartment box 65 to define corresponding freezer and fresh food compartments.
[0017] For the sake of simplicity, the various components of a conventional refrigeration circuit have not been shown. However, with this configuration of refrigerator 2 , the various compressor, condenser, evaporator and the like components are preferably supported upon top panel 60 of freezer compartment box 55 , as well as top cover member 84 . In accordance with the most preferred embodiment of the invention, the evaporator is supported above freezer compartment box 55 while the compressor and condenser are located above fresh food compartment box 65 , with each of these components being accessible upon removing access panel 32 .
[0018] In accordance with the invention, front frame 40 includes top, bottom and opposing side frame members 110 - 113 along with a mullion member 117 that collectively define first and second openings 128 and 129 . In the embodiment shown, opening 128 corresponds to freezer compartment box 55 and opening 129 corresponds to fresh food compartment box 65 . Important in connection with the present invention, as best shown in FIG. 3 , front frame 40 is integrally formed from a single sheet of material. Preferably, front frame 40 is formed by a stamping process such that openings 128 and 129 are stamped out of a single sheet of material such as, for example, aluminum.
[0019] In further accordance with the invention, in addition to establishing openings 128 and 129 , the stamping process creates a plurality of outer edge portions 140 - 143 that correspond to top, bottom and opposing side frame members 110 - 113 respectively. Outer edge portions 140 - 143 are provided with a plurality of openings, one of which is indicated at 144 , which, as will be discussed more fully below, are employed when connecting front frame 40 to the remainder of refrigerator 2 . In addition to outer edge portions 140 - 143 , front frame 40 also includes first and second plurality of inner edge portions 145 - 148 and 153 - 156 . Inner edge portions 145 - 148 and 153 - 156 extend about and define openings 128 and 129 respectively.
[0020] Following the stamping process, front frame 40 undergoes a forming process during which outer edge portions 140 - 143 and first and second pluralities of inner edge portions 145 - 148 and 153 - 156 are folded or bent so as to define an outer peripheral U-shaped channel 161 , as well as a U-shaped mullion channel 164 , both of which open rearwardly as represented in FIG. 4 . Outer peripheral channel 161 and mullion channel 164 are open at rear portions thereof so as to receive outer edge portions of freezer compartment box 55 and fresh food compartment box 65 , as well as peripheral breaker elements 90 and 91 respectively.
[0021] In accordance with the most preferred form of the invention, peripheral frame 40 is provided with a plurality of corner or stiffening brackets 184 - 187 that are respectively arranged at an intersection (not separately labeled) of top and bottom frame members 110 and 111 with opposing side frame members 112 and 113 . Each stiffening bracket 184 - 187 is generally L-shaped having first and second leg portions, indicated at 190 and 191 for bracket 184 , which extend onto top frame member 110 and side frame member 113 respectively. Of course, the remaining stiffening brackets 185 - 187 include corresponding leg portions that extend onto top or bottom frame members 110 , 111 , as well as a respective side frame member 112 , 113 . In any case, stiffening brackets 184 - 187 are preferably fixedly mounted to front frame 40 through respective double-sided adhesive pads 195 - 198 . Once in place, stiffening brackets 184 - 187 provide additional stiffening to front frame 40 so as to minimize racking forces which may occur during shipment.
[0022] Based on the above, it should be readily apparent that front frame 40 , constructed in accordance with the present invention, provides for a simple, cost effective method of manufacture that removes many previously required steps to join top, bottom, opposing side frames and mullion members. By removing unnecessary steps in a manufacturing process, the present invention reduces costs and complexity associated with the construction of refrigerator 2 thereby providing the manufacturer with a competitive advantage.
[0023] Although described with reference to a preferred embodiment of the invention, it should be readily understood that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, while shown in connection with a built-in refrigerator, front frame 40 could also be employed in other side-by-side models, as well as top mount, bottom mount and French door style refrigerators. In general, the invention is only intended to be limited by the scope of the following claims.
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A refrigerator includes cabinet shell including a pair of laterally spaced, upright side walls and a top wall, each of which includes a respective forward portion. A face frame, integrally formed from a single, bent material sheet, is mounted to the forward portion of each of the opposing side and top walls. The face frame includes top, bottom and opposing side frame members, along with a mullion member that extends between either the top and bottom frame members or the opposing side frame members, depending upon desired refrigerator configuration. The mullion member establishes first and second openings that lead into first and second refrigerated compartments or the refrigerator.
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BACKGROUND OF THE INVENTION
[0001] The invention relates to improvements in suspended ceiling grid members and, in particular, to features for improving the structural integrity and performance of such members.
PRIOR ART
[0002] Grid members for suspended ceilings are typically made from steel strip stock roll formed most commonly into a T-shape that, in use, is inverted. Roll formed sheet metal tees customarily have the vertical portion of their cross-sections made of multiple layers of sheet stock. It is known from U.S. Pat. Nos. 4,489,529, 5,979,055, 6,047,511, and 6,446,407, for example, to secure the double layers of a grid tee together by deforming spaced local areas of the web into stitches for holding the layers in abutting contact. The latter patents disclose the formation of stitches in a strip rolling process.
SUMMARY OF THE INVENTION
[0003] The invention involves the lancing of multiple layers of a web in a roll formed sheet metal grid runner to create formations that prevent relative movement between the layers and thereby improve the performance of the grid runner. The disclosed lanced formations can be effectively used to improve the torsional rigidity of a grid runner by locating the formations distal from a neutral torsional axis of the runner. Additionally, the lanced formations can serve to maintain the web layers in abutting contact and thereby ensure that the visual appearance of certain types of grid runners remain uniform.
[0004] In the disclosed embodiments, the lance is in the form of a tab with an angular profile having one side remaining attached to the main body area of the web and the other sides at least partially cut from the main body of the web and at obtuse angles relative to the attached side. The lanced tab is formed with a bend parallel to the attached side to foreshorten the tab relative to the plane of the web and the opening in the web from which it is cut. This foreshortening of the tab in combination with the obtuse angles of its sides assures that a tight fit between its edges and the edges of the hole is created. The tab is preferably bent so that the tab edge of one web layer abuts the hole edge of another web layer and thereby locks the layers together in particular against relative sliding movement between the layers. By resisting relative sliding motion between the layers, the lanced tabs, when properly located on the web, can give the grid tee relatively high torsional rigidity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a fragmentary perspective view of a grid tee embodying the invention;
[0006] FIG. 2 is an enlarged fragmentary view of an area of the web of the tee of FIG. 1 after being lanced;
[0007] FIG. 3 is a cross-sectional view of grid tee lanced tabs in an intermediate formed condition taken in the staggered plane 3 - 3 in FIG. 2 ;
[0008] FIG. 4 is a cross-sectional view of other grid tee lanced tabs in an intermediate formed condition taken in the staggered plane 4 - 4 as indicated in FIG. 2 ;
[0009] FIG. 5 is a somewhat schematic enlarged view of one of the lanced tabs of FIG. 2 ;
[0010] FIGS. 6 and 7 are views similar to FIGS. 3 and 4 , respectively, illustrating the lanced tabs in their final configuration pressed back towards the plane of the web;
[0011] FIG. 8 is a fragmentary perspective view of a second embodiment of a grid tee embodying the invention; and
[0012] FIG. 9 is a fragmentary cross-sectional view of a lanced tab area of the tee taken in the plane 9 - 9 indicated in FIG. 8 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] Referring now to the drawings, and in particular to FIG. 1 , there is shown a form of a grid runner 10 in the general shape of an inverted tee. The grid runner or tee 10 includes a lower horizontal flange 11 and a vertical web 12 . The body of the tee is preferably formed as a single strip of mild steel sheet roll formed into the illustrated profile. The sheet stock is folded on itself at each lateral side or section 13 of the flange 11 so that these flange sections are double layers. Similarly, the web 12 is a structure of double layers 16 , 17 apart from where its upper region includes a third layer 18 . These three layers 16 - 18 exist between an upper edge 19 of one of the two main layers 16 and a downwardly facing edge 21 of the third or minor layer 18 . The third layer 18 is an integral extension of one of the double or main layers 17 and is folded downwardly over the upper edge 19 of the other major layer 16 . As seen in FIG. 1 , for example, the layers 17 , 18 sandwich and laterally trap the other layer 16 . The web 12 includes a reinforcing bulb 22 formed of opposed integral ribs rolled in the respective layers 16 , 17 .
[0014] The web 12 is lanced above the bulb 22 at locations 26 spaced along the length of the runner 10 . In the illustrated example, the lance 27 is arranged in groups of four at each location 26 . The lances, designated 27 , of a group are identical except for orientation; a pair of the lances 27 (at the left in FIG. 2 ) are displaced into the space below the plane of the drawing and the other pair of lances (at the right in FIG. 2 ) are disposed into the space above the plane of the drawing. Each lance or tab 27 of a pair is oriented 180°, in a vertical sense, from the other tab.
[0015] Each lance or tab 27 is partially cut through each of the layers 16 - 18 . The tab 27 when viewed in a plane parallel to the web 12 preferably has a polygonal profile and at least one side 28 that lies at an obtuse angle with a side 29 that remains uncut. The illustrated tabs 27 are shaped like a dovetail having two opposed sides 28 that are cut at obtuse angles with respect to the uncut side 29 . The tab 27 includes a fully cut side 32 extending between the obtuse sides 28 that, in the illustrated case, is parallel to the uncut side 29 .
[0016] The tabs 27 are formed in two operations. In the first operation, the far edge or side 32 remote from the uncut side 29 and portions of the obtuse edges or sides 28 remote from the uncut side are sheared from the three web layers 16 - 18 . At the same time, the tool shears the tab from the main areas of the web layers, it operates to form the tab material by bending it along a line 33 parallel to the sides 29 , 32 . The bend 33 requires the tab material on the side of the bend remote from the uncut side 29 to be drawn or to flow towards the bend. The tab 27 is thus foreshortened when viewed in a plane parallel to the plane of the web 12 .
[0017] FIG. 5 is a diagrammatic illustration of this foreshortening effect where the cut edge or side 32 is displaced vertically from its corresponding edge 34 on the body of the web 12 . The theoretical area 36 lying between the obtuse tab edges 28 and corresponding web hole edges 37 is a measure of the tight interference that can be obtained with the disclosed technique of forming the tab 27 to foreshorten it.
[0018] The second operation on the lances or tabs 27 involves pressing them back from the condition illustrated in FIGS. 3 and 4 towards the plane of the web 12 . The tabs 27 can be returned through a distance of about 75 to 80% of the distance they are originally displaced from the plane of the web. Preferably, the tabs 27 are bent back so that as depicted in FIGS. 6 and 7 , the tab layers are misaligned relative to the layers of the web. In particular, the tabs 27 are pushed back so that the middle layer of a tab straddles the middle layer 16 and one of the outer layers 17 or 18 of the web 12 . With reference to FIG. 6 , in the lanced region the upper part of outer layer 18 and the lower part of outer layer 17 cannot move longitudinally relative to the middle layer 16 because they are trapped by the inner layer of the tabs 27 . With reference to FIG. 7 , in the lanced region, the lower part of the outer layer 18 and the upper part of the outer layer 17 cannot move longitudinally because they are trapped by the inner layer of the tab 27 . The central layer of each tab 27 is reinforced and stabilized by the other two layers helping it to resist lateral deflection out of its final formed position straddling one or the other outer layers 17 or 18 of the web 12 at the opening formed by the respective tab.
[0019] The section views of FIGS. 3, 4 and 6 , 7 are taken in vertical planes for clarity. It will be understood that the above discussion of the offset and straddling by the middle tab layer of the middle web layer 16 and one or the other outer web layers 17 or 18 is applicable at the interface between the tab edges or sides 28 and the edges of the opening corresponding to these tab edges.
[0020] It will be noted that a single one of the lances or tabs 27 is capable of locking the several layers together when formed according to the invention in the described manner. The disclosed arrangement of four tabs affords a high level of redundancy in gripping action to assure reliable interlocking of the layers 16 - 18 .
[0021] When an elongated body made of folded or rolled sheet such as the grid runner 10 is subjected to torsion about its longitudinal axis, the layers of the body tend to shift longitudinally relative to one another. When the lances or tabs 27 are used to improve the torsional stiffness of a tee, it is desirable that the tab edges 28 are oriented at acute angles of between, for example, 0 and 45°, to a line perpendicular to the longitudinal direction of the grid runner. This orientation assures that the reaction forces between the tab and opening from which it is cut when a torque is applied to the grid runner work to resist relative longitudinal slippage between the layers. The position of the lanced tabs 27 near the upper extremity of the web 12 and therefore remote from a neutral torsional axis of the grid member enables the tabs 27 to more effectively resist twisting of the grid member.
[0022] FIG. 8 illustrates another embodiment of the invention applied to a grid runner or tee 41 . The grid runner 41 , in a generally conventional manner, includes a main body 42 and a cap strip 43 . The main body 42 is roll formed from a single sheet metal strip and includes a hollow bulb 44 , a double wall or layer web 46 and single layer flange portions 47 . The flange portions 47 are covered with the cap strip 43 which is folded over the outer edges of the flange portions 47 by a rolling process. The double layer web 46 is provided with lanced tabs 48 configured and grouped as described above in reference to the grid runner 10 . The tabs 48 differ from the tabs 27 in that they comprise only two layers of sheet metal as shown in FIG. 9 but retain the dovetail profile so as to include an edge on each of its opposite sides at obtuse angles to the attached side. FIG. 9 illustrates cross-sections of two typical lanced tabs 48 . As seen there, the tabs 48 , after being formed, are pushed back towards the plane of the web 46 so that one layer of each of the tabs is mechanically locked in a position where it straddles the two layers of the web. The lanced tabs 48 are preferably located near the flange portions 47 so that they are as far as practical, spaced from a neutral torsional axis to obtain greater effectiveness in resisting twisting about the longitudinal axis of the tee. Besides serving to torsionally stiffen a grid tee, the tabs can be useful in preventing the web layers from spreading apart which function can be especially important in certain special grid tee configurations such as disclosed in U.S. Pat. No. 4,535,580, for example. It will be understood that the tabs can be formed in a stamping press when other stamping operations are being performed on the grid tee.
[0023] While the invention has been shown and described with respect to particular embodiments thereof, this is for the purpose of illustration rather than limitation, and other variations and modifications of the specific embodiments herein shown and described will be apparent to those skilled in the art all within the intended spirit and scope of the invention. Accordingly, the patent is not to be limited in scope and effect to the specific embodiments herein shown and described nor in any other way that is inconsistent with the extent to which the progress in the art has been advanced by the invention.
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A roll formed sheet metal grid tee, having a multilayer web, is rigidified by a series of longitudinally spaced tabs lanced through the web. The tabs are cut with a dovetail shape and are foreshortened relative to the holes, made when they are formed, by bending them along a line parallel to a side of the tab that remains uncut. After being foreshortened, the tab is pressed back into its associated hole and tight locking interference is developed between the divergent dovetail sides of the tab and the hole. The tab is incompletely pushed back into the hole so that the layers of the tab are misaligned with corresponding respective layers of the web to assure that the tabs prevent relative shear-like movement and/or spreading of the web layers.
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RELATED APPLICATIONS
[0001] The present application claims the benefit under 35 U.S.C. §371 of International Patent Application No. PCT/EP2011/071966, having an international filing date of Dec. 6, 2011, the content of which is incorporated herein by reference in its entirety.
FIELD
[0002] The invention relates to a method of producing a rotor of an electric machine and moreover to a rotor produced by such method. The rotor is to be usable primarily with high-speed electric machines, in particular high-power electric machines and/or electric machines with rotors of large construction and concomitantly high requirements as to mechanical strength at high circumferential speeds. The invention also relates to an apparatus for producing such rotor.
BACKGROUND
[0003] A common type of construction of electric machines for fulfilling the requirements mentioned are permanently excited electric machines. For permanently excited electric machines with fast-rotating rotors of large construction, for example with rotor diameters greater than 150 mm and speeds above 2000 rounds per minute (rpm), there are specific measures necessary to secure the magnets on the rotor against the considerable centrifugal forces acting on the magnets. Usual measures are: (1) material-bonding attachment of the magnets on the magnetizable rotor carrier or arm by means of an adhesive, (ii) force-fit fixation of the magnets by a nonmagnetic external bandage, (iii) form-fit mounting by “burying” the magnets in a sheet-metal package and by means of mechanical mounting elements, respectively. Measures (i) to (iii) may also be combined.
[0004] All measures involve advantages and disadvantages. Adhesive bonding of the magnets pursuant to (i), in the light of the limited strength of adhesives, involves disadvantages in case of high centrifugal force loads due to high speeds. This effect is particularly pronounced when the rotor at the same time is subject to higher temperatures. Moreover, fatigue is to be expected with adhesives in the course of time, which however is strongly dependent on the environmental conditions in which the rotor is used. The result in the end is substantially uncontrolled lifting off of the magnets when subject to centrifugal forces, and thus a safety risk.
[0005] The magnets can be mounted to the rotor by bandages in force-fitting manner, cf. for example DE 10 2009 043 224 A1, EP 1 369 976 B1 or DE 10 2006 015 037 A1. Common bandages are made of nonmagnetic material or fiber-reinforced plastics and are applied to the rotor with a bias. The bias of the bandage is to be in an appropriate ratio to the centrifugal force to be expected, and possibly should be dimensioned slightly larger than the centrifugal force to be expected. This necessitates fitting tolerances between bandage and rotor that have to be observed relatively closely.
[0006] The common practice for manufacturing bandages of fiber-reinforced plastics materials consists in winding firstly a bandage on a winding mandrel with some undersize and then pulling the bandage onto the rotor. This can be effected e.g. by brief heating of the bandage and “shrinking” the same onto the rotor. For this purpose, there are frequently used so-called “prepregs” having fiber-reinforcements of fiberglass (GFK), carbon fiber (CFK) or ceramic fiber (KFK) materials in a plastics matrix. It has turned out, however, that bandages of such fiber-reinforced plastics materials do not work reliably at all times since it is difficult to pull such bandages onto the rotor with a bias and since they are easily damaged due to their anisotropy and brittleness. The lacking plastic strain capability of fiber-reinforced plastics materials turns out to be disadvantageous as well.
[0007] For producing bandages of metals, an approach has become accepted in which a thin-walled metal tube is made in undersize and is pulled, pressed or shrunk onto the rotor.
[0008] With bandages of metal, there is necessarily a closed metal surface in the air gap between rotor and stator in which there are eddy currents flowing, reducing the efficiency of the machine. Also, additional eddy current heating is unavoidable and in many cases—not least due to different thermal expansion of bandage and rotor core with permanent magnets—leads to unacceptable changes of the bias properties. This becomes felt in disturbing manner in particular when, due to high speed and/or large construction of the rotor, there are occurring high centrifugal force loads during operation. For preventing the losses in the bandage from becoming excessively large, the frequencies of the alternating fields must be kept sufficiently low, so that the closed metal bandage is poorly suited for multi-pole and thus high-torque drives.
[0009] Metal bandages are manufactured generally from non nonmagnetic metals since, when ferromagnetic or magnetizable metals are used, part of the magnetic flux is directly short-circuited from magnet to magnet and does not flow through the stator.
[0010] Bandage concepts necessarily involve an increase in the magnetic gap between rotor and stator. This is inconvenient especially as the effectiveness or efficiency of an electric machine in a non-linear relationship depends on the size of the air gap. Fractions of mm of more or less air gap may already have dramatic effects on efficiency.
[0011] Also with form-fitting attachment of the magnets according to variant (iii), a magnetic return path in magnetic portions above and between the magnets typically cannot be avoided, which thus results in corresponding power and efficiency degradation. In so far as form-fitting mounting concepts have been developed in which the air gap is not significantly larger than without mounting of the magnets, as described e.g. in DE 10 2008 055 893 A1, these are relatively complex as regards manufacture and assembly of the rotor.
[0012] By combining the afore-mentioned approaches, the disadvantages thereof can be kept within limits, however, at the cost of a relatively complex construction. An example of a construction combining a bandage concept with form-fitting or positive attachment of the magnets, can be found in DE 10 2007 771 B4. In the latter, the magnets are generally held by force-fit on the periphery of the rotor shaft by means of a bandage of a nonmagnetic metal tube. The magnets in addition are supported on the rotor shaft in guide groves in radially movable manner, and the bandage is centrally connected to the rotor shaft by two face-side end caps. These end caps can be expanded elastically in radial direction and thus hold the bandage centered with respect to the rotor axis also in a radially lifted state of the magnets at high speeds.
SUMMARY
[0013] It is the object of the invention to make available a novel method of mounting components of a rotor, in particular of permanent magnets in case of an electric machine excited by permanent magnets, on a rotor body through which the rotor components can be secured against mechanical force effects, in particular those caused by centrifugal forces, in simple and permanently reliable manner. In particular, the assembly expenditure for mounting the components is to be reduced over known solutions. Moreover, the invention is to indicate a correspondingly manufactured rotor.
[0014] According to the invention, this object is met by a method of producing a rotor of an electric machine, the rotor comprising a rotor body adapted to be rotated about a motor axis as well as at least one rotor component to be mounted to the rotor body, the method comprising the steps of: arranging the rotor component on the rotor body and winding a wire-like structure around the outer circumference of the rotor body having the rotor component arranged thereon so as to form a bandage, with the wire-like structure during winding thereof being held under an adjustable bias. The bandage obtained in this way may also be referred to as a “wire-wrap bandage”. For example, the rotor body may be in connection to a motor shaft.
[0015] The utilization of a wire-like structure, i.e. an elongate and flexible structure, which is generally thin (i.e. has a very small cross-sectional area in relation to its length), for winding around the rotor permits the use of material for the wire-wrap bandage that is of comparatively high strength due to the manufacturing process used for wires. Particularly high solidification or hardening is achieved with drawn wires, due to the manufacturing process of the same, in particular cold-drawn wires. Such wires as a rule are made from metal materials. For the bandages according to the invention, for example wire-like structures drawn from titanium, titanium alloys or certain stainless steels have proven suitable. Such materials can be used for making wire-like structures of high tensile strength. Such wire-like structure permits high biasing forces to be obtained already with low bandage thickness, and thus are excellently suited to fix rotor components that are subject to high centrifugal forces. In addition thereto, it has turned out that a number of such wire-like structures, also after hardening thereof occurring during forming into the wire-like structure, still have a sufficient plastic strain capability so that they will not break immediately upon reaching the tensile strength, but rather react to local excessive loads by elongation while retaining the tensile force. This holds, for example, for a number of metals and metal alloys, including the afore-mentioned metal materials titanium and alloys thereof as well as some stainless steels. Such wire-like structures thus do not only display high strength, but are also “good-natured”, i.e. they can be wound reliably and with defined bias.
[0016] The higher the bias adjusted in winding the bandage according to the invention, the higher the centrifugal forces that the bandage may be subject to, for a given material cross-sectional area. With the afore-mentioned materials, it is easily possible to choose a bias in a range just slightly below the yield strength of the wire-like structure. Often it will even be possible to work immediately at the yield strength of the wire-like structure or to slightly overstretch the wire-like structure. In some cases it will even be possible—as there is a certain distance in terms of strain between the tensile strength and the yield strength—to wind the wire-like structure with a bias that is above the yield strength of the same and that may possibly come close to the tensile strength of the same. It is advantageous in this regard when substantially non-brittle wire-like structures are used with which, in a tensile test, the tensile strength is as remote as possible from the yield strength in terms of strain. It is favorable when the strain, upon reaching of the tensile strength, is far above the strain upon reaching of the yield strength, as this permits high plastic strain. This property distinguishes the wire-like structures according to the invention over high-strength, but brittle materials, such as glass fiber or ceramic fiber reinforced materials in which yield strength and tensile strength are very close to each other in terms of strain.
[0017] The term “yield strength” in essence is to be understood as the stress at which, in a tensile test with a wire-like structure, an appreciable plastic or permanent deformation occurs, e.g. as indicated in a stress/strain diagram. For most wire-like structures, the strain limit, as a rule the 0.2% offset strain limit Rp 02 , can be used. With wire-like structures displaying a pronounced yield strength Re, the yield strength Re may also be used as reference point as of which the structure starts to undergo appreciable plastic deformation.
[0018] The tensile strength Rm of a wire-like structure is the stress determined from the maximum tensile force a tensile test, e.g. as indicated in a stress/strain diagram, in relation to the original cross-sectional area of the sample. In a stress/strain diagram, the tensile strength Rm results from the maximum stress occurring prior to fracture of the wire-like structure.
[0019] For producing a bandage of wire-like structure (wire-wrap bandage), the winding process on a rotor can be performed quite simply. There are just required a lathe for the rotor and an arrangement for adjusting and optionally controlling the bias or tensile force on the wire-like structure. The bandage may also be wound and attached relatively easily on rotors having complicated geometry of the outer surface, e.g. in the form of polygons. By utilizing wire-like structures of reduced cross-sectional area only, it is possible to keep within tolerable limits magnetic losses and losses due to eddy currents occurring in use. The selection of suitable materials for the wire-like structure may be contributory to this effect as well.
[0020] In the method, the wire-like structure may be unwound e.g. from a supply roll and passed through a wire guide means onto the outer circumference of the rotor to be provided with a wire-wrap. The rotor body resting on a support may be caused to rotate about its rotor axis, with the bias of the wire-like structure in the section between the wire guide means and the rotor body being adjusted by cooperation of the wire guide means and a torque control acting on the rotor body.
[0021] The wire guide means may act e.g. as a bias supporting means which sets a corresponding resistance force corresponding to the desired bias against the transport of the wire-like structure. This resistance force is overcome by a torque produced by a corresponding rotational force acting on the rotor. In doing so, the desired bias in the wire-like structure is produced.
[0022] The bias of the wire-like structure can be actively controlled during winding, typically by a feedback control.
[0023] When the wire guide means is used, the active control of the bias of the wire-like structure may be effected with the aid of the wire guide means. The latter may be provided e.g. in the form of a bias setting means for supporting the bias force. The current bias of the wire-like structure between the bias setting means and the outer circumference of the rotor is measured, and in accordance therewith the supporting force of the wire guide means to be overcome for conveying the wire-like structure through the wire guide means is increased or decreased accordingly. As an alternative, it is also possible to control the torque of the drive acting on the rotor body in accordance with the prevailing bias and the nominal bias of the wire-like structure in the section between wire guide means and rotor body. In certain cases, it may also be advantageous to actively control, typically by a feedback control, both the supporting force of the wire supply means and the torque of the drive acting on the rotor body.
[0024] In a preferred development, the maximum bias of the wire-like structure may be adjusted between 50 and 100% of the tensile strength of the wire-like structure, preferably between 70 and 100% of the tensile strength of the wire-like structure, and in particularly preferred manner between 80 and 100% of the tensile strength of the wire-like structure. The closer the bias is set to the tensile strength of the wire-like structure during the winding operation, the higher the centrifugal forces the bandage may be subjected to for given cross-sectional area of the bandage.
[0025] The bias may vary in the course of the winding operation, e.g. a lower bias may be set at the beginning and at the end of the winding operation, typically by a feedback control.
[0026] The maximum bias can be selected as a function of the following parameters: (i) rotor speed and/or (ii) mass of the rotating rotor components to be mounted (centrifugal force) and/or (iii) thermal conditions of use and/or (iv) mechanical load conditions (e.g. shocks).
[0027] The maximum bias of the wire-like structure may be set to values up to 700 MPa, preferably up to 1300 MPa and in particularly preferred manner up to 2000 MPa.
[0028] In preferred embodiments, the maximum bias of the wire-like structure can be set to values of at least 100 MPa, preferably at least 500 MPa and in particularly preferred manner at least 1000 MPa.
[0029] In particular, the bias of the wire-like structure at the beginning of the winding operation within a predetermined winding length on the outer circumference of the rotor can be increased from zero or an initial value that is at most 30%, preferably at most 20% and in particularly preferred manner at most 10% of the maximum bias, to a maximum winding bias. In addition thereto or as an alternative, the bias of the wire-like structure at the end of the winding operation within a predetermined winding length on the outer circumference of the rotor can be reduced from a maximum winding bias to zero or a final value which is at most 30%, preferably at most 20% and in particularly preferred manner at most 10% of the maximum bias. For example, the bias of the wire-like structure can be varied at the beginning and/or end of the winding operation within at least one rotor circumferential length to be wound, preferably within at least two rotor circumferential lengths to be wound and still more preferably within at least three rotor circumferential lengths to be wound, between the maximum bias and zero or the initial/final value.
[0030] At the beginning of the winding operation, a beginning—and/or towards the end of the winding operation, an end—of the wire-like structure can be fixed in axial direction laterally of the bandage wrap on the outer circumference of the rotor. To this end, e.g. corresponding screws and/or bolts may be used. For this purpose, the rotor may have axially beside the bandage wrap one projecting portion each. These portions may extend beyond the rotor component to be mounted on the rotor.
[0031] Winding of the wire-like structure on the outer circumference of the rotor preferably takes place at an angle parallel to a plane orthogonal to the rotor axis. However, winding may also be effected at an angle to such plane.
[0032] The outer circumference of the rotor also may have several winding layers of the wire-like structure wound on top of one another. The several winding layers arranged on top of one another may be wound at an identical winding angle with respect to a plane orthogonal to the rotor axis, or may be wound at different winding angles with respect to a plane orthogonal to the rotor axis. In addition thereto, it is also conceivable to wind the several winding layers arranged on top of one another from different wire-like materials. All of these measures permit specific settings in operation of the electric machines to be taken account of by way of the wire-wrap bandage. This holds in particular with regard to the thermal stress to be expected, as the thermal expansion of the various winding layers may be designed each for a specific one of a plurality of operating temperatures to be expected, and/or as each winding layer may be made of a material that is optimized with respect to a respective operating temperature to be expected.
[0033] Particularly, a wire-like structure with a diameter of at least 0.2 mm, preferably with a diameter of at least 0.3 mm and in particularly preferred manner with a diameter of at least 0.5 mm, may be wound onto the outer circumference of the rotor.
[0034] Moreover, a wire-like structure having a diameter of at most 3 mm, preferably a diameter of at most 2.5 mm and in particularly preferred manner a diameter of at most 2 mm, may be wound onto the outer circumference of the rotor.
[0035] A modification that turned out particularly favorable is an embodiment in which a wire-like structure having a diameter of about 1 mm is wound onto the outer circumference of the rotor.
[0036] The wire-like structure does not need to be of completely round cross-section. Other cross-sections are conceivable as well, in particular oval, quadrangular concave, quadrangular convex. The diameter meant thus is an effective diameter which results from a circle circumscribing the cross-sectional area of the wire-like structure.
[0037] Furthermore, it has turned out that winding a bandage of wire-like material on a rotor, as described hereinbefore, leads to safe mounting of rotor components on an outer circumference of the rotor which has a diameter of at least 30 mm, preferably of at least 100 mm and in particularly preferred manner of at least 300 mm. It has turned out in addition that safe mounting of rotor components is possible for diameters of the outer rotor circumference to be wound between about 2000 mm and 2500 mm and as far as up to 3500 mm.
[0038] Moreover, it has turned out that mounting in the manner described hereinbefore provides for safe attachment of rotor components up to maximum speeds of at least 4000 rpm and maximum centrifugal accelerations of 36000 m/s 2 , respectively. It has been established in preferred embodiments that safe conditions can be achieved even with maximum speeds of up to 5000 rpm and maximum centrifugal accelerations of up 56000 m/s 2 , respectively, and in particularly expedient embodiments even with maximum speeds of up to 6000 rpm and maximum centrifugal accelerations of up to 81000 m/s 2 , respectively.
[0039] Opposite the rotor, usually via an air gap, there is disposed a stator carrying electric windings. The rotor has poles formed of permanent magnets that are located opposite corresponding magnet poles on the stator.
[0040] The wire-like structure can be wound across an axial length of at least 25 mm on the outer circumference of the rotor, preferably across an axial length between 25 mm and 1000 mm, and in particularly preferred manner across an axial length between 50 mm and 1000 mm.
[0041] The rotor component to be mounted primarily comprises permanent magnets of a permanently excited rotor. The rotor component preferably is attached to an outer surface of the rotor body. For example, permanent magnets of a rotor often are in the form surface magnets. These may either be arranged just at the surface and then may be held solely with the aid of the wire-wrap bandage, or may be held on the rotor body in addition by material bonding, force-fit and/or form-fit.
[0042] The wire-like structure can be wound onto a plurality of rotor components distributed around the outer circumference of the rotor, with the outsides of the rotor components, in a cross-section orthogonal to the rotor axis, being arranged on a polygonal course, and with the wire-like structure being wound around the polygonal course. Applying a wire-wrap bandage in the manner described is particularly expedient with an arrangement of rotor components, e.g. permanent magnets, along the outside of the rotor so that the outsides of the rotor components constitute the supporting or abutment surface for the bandage. To this end, the outsides of the rotor components need not be ground first to a suitable outer diameter of the rotor, as it is generally necessary for applying a pre-fabricated bandage. Instead, the wire-like structure can be wound directly onto a polygonal outer contour, even if there are two circumferentially successive rotor components directly abutting each other.
[0043] The rotor component to be mounted, at least with respect to forces acting in circumferential direction, may also be attached in form-fit manner in recesses formed in the rotor body. The rotor component to be secured by way of the wire-wrap bandage against centrifugal forces acting in radial direction can be designed e.g. in the form of “buried” magnets. Such magnets are arranged in pockets formed in the rotor body. Securing against forces acting in circumferential direction then is implemented substantially in form-fit manner by the rotor body. Securing against centrifugal forces acting in radial direction can be obtained completely or partially by the wire-wrap bandage.
[0044] In certain embodiments, there may be provided portions axially beside, i.e. to the left and the right, of the rotor component in which deflection of the winding angle of the wire wrap takes place.
[0045] However, in addition to the permanent magnets of a rotor excited by permanent magnets, there may be provided still other permanent magnet configurations in the rotor, such as e.g. flux-concentrating trapezoidal geometries. Also such permanent magnet configurations, be they disposed at the surface of the rotor body or embedded in the rotor body completely or partially, can be held by the wire-wrap bandage. In these configurations, too, the centrifugal forces act against the adhesive strength or apply loads to (generally ferromagnetic) supporting webs which then are supported by the wire-wrap bandage of wire material.
[0046] The wire-wrap bandage, however, may also serve to secure other rotor components than permanent magnets against centrifugal forces acting in radial direction. Similar to a rotor equipped on the outside thereof with surface magnets (inner rotor), other rotors equipped with rotor components that are subject to centrifugal forces during operation can be provided with the wire-wrap bandage as well. Such rotor components may be e.g. high-speed inductive contactors in which metal pieces of special materials are embedded in a rotor carrier.
[0047] It is even conceivable to wind a wire-like structure onto a rotor that is not provided with permanent magnets.
[0048] Particularly, the wire-like structure for producing the bandage may be made from metal material. The term metal in this context is to be understood to comprise pure metals and particularly metal alloys. Metals generally have good mechanical behavior. In particular, they often have sufficiently high tensile strength for producing the necessary bias, along with good plastic deformability.
[0049] The wire-like structure preferably has a tensile strength of at least 700 MPa and more preferably of at least 1300 MPa, with at least 2000 MPa being particularly preferred.
[0050] The wire-like structure preferably has a modulus of elasticity (Young's modulus) of at the most 250 GPa and more preferably of at the most 180 GPa, with at the most 130 GPa being particularly preferred. The Young's modulus should be selected to achieve bias and elasticity as high as possible. This can be achieved particularly well when the Young's modulus is not excessively high, especially when the Young's modulus is within the ranges indicated. A relatively low Young's modulus also provides the advantage that thermal strain differences between rotor and bandage are translated to slight stress differences only and that strain defects have less critical effects.
[0051] The wire-like structure preferably has a plastic deformability of at least 1% and more preferably of at least 3%, with 5% being particularly preferred. The plastic deformability indicates the relative strain between offset strain limit Rp 0.2 or yield strength, respectively, and tensile strength Rm in the stress-strain diagram in %.
[0052] The use of a wire-like structure made of metal permits low thermal stresses between rotor and bandage, as the metal of the wire-like structure and the metal of the rotor core may be selected such that both show similar thermal expansion.
[0053] In embodiments, the wire-like structure may have an electric conductivity of at the most 10 MA/(V·m), preferably at the most 5 MA/(V·m), with at the most 3 MA/(V·m) being particularly preferred. This design possibility has the aim of preventing possibly arising eddy currents within the wire-wrap bandage due to the magnetic alternating fields introduced during operation of the machine. To this end, it is possible in addition or as an alternative to provide the wire-like structure with an insulating varnish coating or an insulating spun sheathing. The insulating varnish coating or spun sheathing can be applied to the wire-like structure prior to winding of the same, e.g. by pulling the wire-like structure through a corresponding varnish bath. As an alternative, an insulating varnish coating or wound sheathing can also be applied after the winding operation. This is preferably effected layer for layer.
[0054] This measure is preferably employed with machines having a large number of poles, e.g. machines with more than 4 poles and/or with machines using high rotational frequency, e.g. a rotational frequency of 2000 rpm or more. With such machines, eddy current losses, which are proportional to the square of the wire diameter and to the square of the frequency, make themselves felt in extremely negative manner.
[0055] In producing a multi-layer wire-wrap bandage, there may be applied a layer of insulating material between individual layers of the wire-like material wound onto the circumference of the rotor.
[0056] In accordance with embodiments, the wire-like structure can be made from nonmagnetic material. In this context, any material not having ferromagnetic properties may be deemed to be nonmagnetic. Nonmagnetic materials principally have a magnetic conductivity or magnetic permeability that is independent of the strength of external magnetic fields, in particular those which the bandage in the electric machine is subjected to during operation. In case of suitable nonmagnetic materials, the value of the magnetic permeability often is in the order of one. Nonmagnetic materials are chosen in order to possibly suppress an influence on the magnetic flux between rotor and stator of the electric machine in the air gap due to magnetic short-circuiting via the bandage.
[0057] The wire-like structure, for example, can be made of titanium or a nonmagnetic stainless steel. The term “titanium” in this context is to comprise pure titanium as well as titanium alloys. The term “stainless steel” is to be understood in general, as collective term for high-alloy, low-alloy or unalloyed steels of specific purity, e.g. steels whose contents of steel accompanying elements, such as sulfur and/or phosphorus, do not exceed a certain limit. More details for distinguishing stainless steels from basic steels and quality steels can be found in DIN EN 10 020 (2000).
[0058] Both materials offer a good compromise with respect to the properties demanded. Titanium is nonmagnetic and, in comparison with other metals, has a quite low modulus of elasticity (Young's modulus) of approx. 105 GPa with a plastic strain capacity between 5 and 10%. With wires drawn from titanium, a bias suitable for many applications and ranging between 1000 and 1300 MPa can be obtained. At the same time, titanium is nonmagnetic to such an extent that the magnetic situation in the air gap, apart from an increase of the magnetically effective air gap, is affected only insignificantly. The electric conductivity of titanium is rather low, so that eddy currents do not make themselves felt excessively. Another contributory fact in this regard is that the thermal expansion of titanium is very similar to that of rotor cores commonly used. Heating of bandage and rotor core caused by eddy currents thus does not result in an alteration of the bias. This facilitates also dimensioning.
[0059] The same holds for a number of nonmagnetic or non-magnetizable stainless steels. Examples are stainless steels with material numbers 1.4301 (tensile strength≈1770 MPa), 1.4401 (tensile strength≈1500 MPa), 1.4541, Phynox-Elgiloy CoCr20Ni16Mo7 (tensile strength up to 2000 MPa).
[0060] As an alternative, the wire-like structure can be made from a ferromagnetic material. In this context, a ferromagnetic material is understood to be a material that can be magnetized by an external magnetic field such that the magnetic field in the interior of the material is strengthened disproportionately to the strength of the magnetic field applied. Ferromagnetic materials have a value of magnetic permeability that is dependent on the strength of an external magnetic field. As long as magnetic saturation of the ferromagnetic material is not yet reached, the magnetic permeability of ferromagnetic materials is much higher than one. This condition is striven for in operation.
[0061] The winding is applied to the rotor magnets in the air gap between rotor and stator. As the actually present air gap for safety reasons must have a certain minimum size of typically 1 to 3 mm, attaching the wire-wrap bandage results in an extension of the magnetically effective air gap and thus results in a reduction of efficiency of the electric machine. This reduction is drastic as the efficiency of an electric machine is disproportionately dependent on the size of the air gap. When a wire-like structure of ferromagnetic type itself is used for forming the wire-wrap bandage, the wire-wrap bandage virtually extends the rotor. Thus, the result upon application of the bandage is merely a slightly larger external radius of the rotor, however no increase in the magnetically effective air gap.
[0062] In case the entire wire-wrap bandage is ferromagnetic, undesired magnetic short-circuiting results between adjacent poles. For avoiding such magnetic short-circuiting, it may be advantageous to bridge the space between individual poles of the machine (e.g. the space between the permanent magnets on the rotor in case of a machine excited by permanent magnets) using non-magnetizable or more poorly magnetizable wire-wrap bandage material. This can be achieved by employing a ferromagnetic material having successive first and second portions, with the first portions being easier to magnetize and the second portions being harder to magnetize. The arrangement of easier and harder magnetizable portions may be performed in advance, and in doing so care has to be taken that the distances between the first portions and the length of the second portions, respectively, corresponds to the distance between successive poles of the machine that varies with increasing radius of the rotor body. The ferromagnetic material in particular may be a soft-magnetic basic material that is subjected to a treatment in which influence is taken on the magnetic permeability and/or magnetic remanence and/or coercitive field strength of the material in the first portions and the second portions, respectively, by way of suitable measures. The permeability can be changed, for example, in certain portions by mechanical treatment, such as hardening, and/or thermal treatment, such as annealing. In similar way, the magnetic remanence and coercitive field strength can be influenced.
[0063] For example, in portions of the wire-like structure disposed between the rotor poles in the wound state, a high magnetic reluctance (i.e. lower magnetic permeability) can be introduced. This greatly reduces the afore-mentioned magnetic short-circuiting between the rotor poles.
[0064] For the wire-like structure, there may be used an anisotropic ferromagnetic material that is magnetizable such that the preferred direction of the vector of the magnetization after winding points in the radial direction of the rotor. The advantage of this material characteristic resides in that the preferred direction of the magnetizability of the wire material is parallel to the magnetizing direction of the rotor permanent magnets.
[0065] Disorder and thickness increases due to path changes can largely be avoided when the wire-like structure is composed of individual wires wound in parallel.
[0066] By means of the manufacturing steps described hereinbefore, it is possible to produce a rotor for an electric machine. The electric machine comprises a rotor body adapted to be rotated around a rotor axis being connected to a motor shaft, and has at least one rotor component to be mounted on the rotor body and which has a wire-wrap bandage of a wire-like structure that is wound around an outer circumference of the rotor body having the rotor component disposed thereon, so as to form a bandage. The wire-like structure is held on the rotor body under an adjustable bias, with the average bias of the wire-wrap bandage thus formed being greater to withstand the largest centrifugal forces to be expected during operation. Such a rotor may have one or more of the properties described hereinbefore. In addition to the manufacturing method described, such a rotor is deemed to constitute patentable subject matter of its own.
[0067] The invention moreover relates to an apparatus for producing a rotor for an electric machine. The rotor comprises: a rotor body adapted to be rotated around a rotor axis, e.g. by being connected to a motor shaft, at least one rotor component to be mounted on the rotor body as well as a wire-wrap bandage of a wire-like structure that is wound around an outer circumference of the rotor body having the rotor component disposed thereon so as to form a bandage. The apparatus comprises: a wire guide means for guiding the wire-like structure onto the outer diameter of the rotor to be provided with a wire wrap, and a support for the rotor body which permits the rotor body resting thereon to be set into rotation. Furthermore, the apparatus permits adjustment of the bias of the wire-like structure by cooperation of the wire guide means and a torque control acting on the rotor body. The apparatus may comprise a control for actively controlling the bias of the wire-like structure in the section thereof between the wire guide means and the rotor body by cooperation of the wire guide means and the torque control acting on the rotor body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0068] The invention will be described in more detail hereinafter by way of embodiments with reference to the drawings wherein:
[0069] FIG. 1 shows a simplified schematic illustration of an apparatus for making a rotor with wire-wrap bandage according to an embodiment;
[0070] FIG. 2 shows a simplified schematic sectional view along the rotor axis, illustrating half of a rotor provided with a multi-layer wire-wrap bandage according to an embodiment;
[0071] FIG. 3 shows a simplified schematic illustration of a rotor provided with a wire-wrap bandage according to an embodiment; and
[0072] FIG. 4 shows a simplified schematic sectional view along the rotor axis, illustrating a rotor with a multi-layer wire-wrap bandage according to an embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0073] The figures illustrate embodiments of the rotor provided with a wire-wrap bandage and of the apparatus for producing the rotor. The figures equally use the same reference numerals for designating like or similar components. However, such components are described in more detail referring to one of the figures only, while it is to be understood that such description is also applicable to the component(s) bearing the same reference numeral in the other figures, unless express reference is made to specific differences.
[0074] FIG. 1 shows in a highly simplified schematic view an apparatus 100 for producing a rotor 10 having an outer circumference 12 and a rotor body 14 , according to an embodiment. Rotor 10 has an axis of rotation A and is designed in essence to be rotationally symmetric with respect to this axis of rotation A.
[0075] Rotor 10 serves for use with an electric machine, not shown in the drawings, which has a stator and a rotor that are coaxially arranged around a common axis A. Between rotor 10 and stator (not shown), there is provided an air gap (in FIG. 1 adjacent the outer circumference of rotor 10 ).
[0076] The stator generally carries electric windings that are arranged around winding cores and facing the rotor via the air gap. The electric machine preferably is an electric machine excited by permanent magnets in which the rotor 10 is provided with permanent magnets 16 (shown schematically in FIG. 1 , cf. also FIG. 2 or FIG. 4 ) which are disposed around the outer circumference 12 (internal rotor) or an inner circumference (external rotor) of rotor 10 , respectively, so as to face the stator windings formed on the stator via the air gap. In the construction illustrated in FIG. 1 , rotor 10 is designed as internal rotor in which the permanent magnets 16 are disposed near an outer circumference 12 of rotor 10 . The permanent magnets 16 may be mounted on the rotor surface as surface magnets and/or may be received completely or partially inside pockets formed in rotor body 14 , in the manner of so-called “buried” magnets.
[0077] Rotor 10 consists of several separate parts. These include magnetically active parts, such as the permanent magnets 16 , but also a magnetic return path via which the magnetic flux within rotor 10 takes place between the permanent magnets 16 . The magnetic return path is not shown in more detail in the figures. It may have the configuration of a hollow cylindrical element and serve at the same time as a structural part, i.e. as supporting member, for the permanent magnets 16 . As an alternative or in addition, there may be provided further structural elements, e.g. inductive contactors in which metal pieces of specific materials are embedded in a rotor carrier or arm, or other permanent magnet configurations provided in rotor 10 , e.g. trapezoidal geometries that concentrate magnetic flux.
[0078] The permanent magnets 16 preferably are radially magnetized, i.e. the vector of magnetization of the same has a preferred direction pointing in radial direction either away from axis A outwardly or toward axis A inwardly.
[0079] The permanent magnets 16 , but also other components, as described, are subjected to high centrifugal forces during operation of the electric machine and thus have to be attached to the rotor body 14 or other structural parts in correspondingly firm and reliable manner. This can be effected by way of one or more of the constructions described at the outset, i.e. by material bonding using adhesive, by force-fit using a bandage and/or by form-fit by embedding in pockets formed in rotor body 14 or by structural parts cooperating with rotor body 14 , respectively. In case a bandage is used for attachment, it is provided according to the invention to use a wire-wrap bandage 18 according to embodiments still described in more detail hereinafter. The wire-wrap bandage 18 is illustrated in FIG. 1 merely by its reference numeral 18 . It is shown in more detail in various embodiments in FIGS. 2 to 4 . If reference is made to numeral 18 hereinafter, this is to be understood to the effect that the respective statements hold for all embodiments of the bandage, unless expressly stated otherwise.
[0080] Bandage 18 is applied to the outer circumference 12 of rotor 10 with a bias and thus holds the individual parts of the rotor 10 together. In addition thereto, the individual parts of the rotor 10 may be joined to each other by means of other connections, e.g. mechanical form-fit connections, adhesive connections etc.
[0081] Bandage 18 , in the installed state of rotor 10 , is located in the air gap between rotor 10 and stator. The bandage 18 , at least when it is made from nonmagnetic material, thus increases the distance between the mutually facing, magnetically active parts of rotor 10 and stator since, for safety reasons, the remaining air gap, i.e. the distance between the mutually opposite movable parts of rotor and stator, cannot be reduced below a minimum measure which, depending on the particular design of the electric machine, is between 1 mm and 3 mm. It is to be understood that attempts are made to form the bandage 18 as thin as possible. However, there are limits in this regard as well, since the bandage 18 can secure the rotor components (e.g. permanent magnets 16 ) to be secured against centrifugal forces only against such centrifugal forces that do not significantly exceed the bias of the bandage multiplied by the cross-sectional area of the same. The thicker the bandage 18 , the higher the tolerable centrifugal forces with identical bias of the bandage. In practical application, the thickness of the bandage is relatively low and is in the range of just a few mm or even fractions of mm. For example, a rotor having a diameter of 40 cm, magnets with a thickness of 12 mm and a nominal speed of 3800 rpm, may have a bandage thickness of 0.9 mm. This bandage can be wound as a single layer from 0.9 mm thick wire or in two layers from 0.5 mm thick wire or in three layers from 0.35 mm thick wire. The wire in particular can be made from titanium or a titanium alloy. A wire e.g. of titanium Ti-6Al-4V ELI or a comparable titanium alloy has turned out suitable in this regard. In the illustrations of FIGS. 1 to 4 , the bandage 18 is shown with a disproportionately large thickness.
[0082] In the method depicted in FIG. 1 , a wire-like structure 20 (in the following also referred to as winding wire) is unwound from a supply roll 22 rotatably supported by a supporting block and is guided by a rope or wire guide 24 onto the rotor 10 to be provided with a bandage. The rope or wire guide 24 , indicated in FIG. 1 only schematically, comprises a guide means 26 for engagement with the wire-like structure 20 such that the wire-like structure 20 is held in guide means 26 with a holding force corresponding to the desired bias of the wire-like structure 20 being wound onto rotor 10 . If the wire-like structure is to be transported through guide means 26 , a transportation force directed counter to this holding force has to be applied. During transport through the guide means, due to the retaining or holding force a bias proportional to the holding force is created in the wire-like structure 20 in its section between guide means 26 and rotor 10 . The guide means 26 thus at the same time has the function of a bias actuator that sets a bias force resulting in bias of the wire-like structure 20 in its section 20 a between guide means 26 and rotor 10 .
[0083] The rotor 10 to be wound, i.e. to be provided with the wire-wrap bandage, rests on a support 28 coupled to a drive motor (not shown). The support 28 is formed e.g. in a supporting block. The drive motor is operated in torque-controlled manner. Both the drive motor and the guide means 26 are connected to a control means 30 . This control means 30 takes over the bias control in such a manner that the control means 30 drives the drive motor for the rotor 10 as well as the guide means 26 so as to determine a specific biasing force and a predetermined torque of the drive motor. The control means 30 preferably performs control such that the actual bias in section 20 a of the wire-like structure is detected by a sensor 32 and a corresponding signal is fed to control means 30 . By way of a comparison between desired or nominal bias of the wire-like structure 20 and the actual bias detected by the sensor 32 in section 22 a , the control means 30 controls the guide means 26 and/or the drive motor of rotor 10 such that the actual bias tracks the desired bias as exactly as possible.
[0084] The amount of the predetermined and possibly actively track-controlled bias of the wire-like structure 20 and possibly the accuracy of the tracking control may be determined on the basis of various parameters resulting from the subsequent operation and conditions of use of the rotor 10 . Especially the following parameters are feasible: (1) rotor speed and/or (2) mass and arrangement of the rotating rotor components to be secured against centrifugal forces (e.g. permanent magnets 16 ) and/or (3) subsequent thermal conditions of use and/or (4) subsequent mechanical load conditions (e.g. shocks) of the electric machine. In addition thereto, it has to be considered that the material and the geometry (in particular the cross-sectional area) of the wire-like structure 20 used to form the wire-wrap bandage 18 has an influence on the maximum settable bias. It has turned out in some embodiments that it is favorable to adjust the maximum bias of the wire-like structure 20 in section 20 a between 50 and 100% of the tensile strength of the wire-like structure, in other embodiments in particular to values between 70 and 100% of the tensile strength of the wire-like structure 20 , and in still other embodiments to values between 80 and 100% of the tensile strength of the wire-like structure 20 .
[0085] More thorough investigations have revealed furthermore that it is expedient to establish the bias of the wire-like structure 20 in section 20 a not in a sudden at the beginning of the winding operation, but rather to increase the bias within one to three revolutions of the rotor 10 from zero or a relatively low initial value to the predetermined maximum bias. In like manner, it has turned out expedient to decrease the bias of the wire-like structure 20 in section 20 a at the end of the winding operation slowly from the maximum bias provided to zero or a relatively low final value. For example, the bias both at the beginning of the winding operation and at the end of the winding operation may be established and released, respectively, within one to three revolutions of the rotor 10 .
[0086] At the beginning of the winding operation, the wire-like structure 20 is mounted at a fixing point provided laterally of the rotor body 14 , e.g. a bolt or screw. In like manner, the wire-like structure 20 at the end of the winding operation is mounted at a fixing point provided laterally of the rotor body 14 , e.g. a bolt or screw. These fixing points are not illustrated in the drawings.
[0087] Eddy currents induced within the wire bandage 18 by the magnetic alternating fields occurring during operation of the electric machine can be suppressed generally in the wire-wrap bandage 18 in that the bandage 18 is composed of a wound, single wire-like structure 20 the cross-sectional area of which does not allow higher electric currents. Moreover, if measures are taken to suppress current flow between possibly mutually abutting sections of the wound wire-like structure 20 , e.g. with the aid of a suitable insulation of the wire-like structure 20 by a coating of insulating material, eddy currents are effectively suppressed. It has turned out that, with diameters of the wire-like structure 20 between 0.3 mm and 2 to 3 mm, eddy currents can be kept sufficiently low. The afore-mentioned larger diameters of the wire-like structure 20 between 1 and 3 mm permit effective mounting of rotor components also with respect to centrifugal forces to which such components are subjected to in large and high-speed machines. For example, a rotor having a diameter of 40 cm, magnets with a thickness of 12 mm and a nominal speed of 3800 rpm may have a bandage thickness of 0.9 mm, consisting of one layer of 0.9 mm thick wire, of two layers of about 0.5 mm thick wire or three layers of about 0.35 mm thick wire. The wire may be made in particular from titanium or a titanium alloy. A suitable wire has turned out to be e.g. a wire of titanium Ti-6Al-4V ELI or a comparable titanium alloy. A preferred diameter of the wire-like structure 20 is about 1 mm Speaking of diameter of the wire-like structure 20 in this context, this does not mean that the wire-like structure 20 must have a strictly circular cross-sectional shape. Other cross-sectional shapes are conceivable as well, such as oval or angular cross-sectional shapes. The term diameter in such cross-sectional shapes refers to the effective diameter as measure of the cross-sectional area.
[0088] Moreover, it has turned out expedient to make the wire-like structure 20 of a material having an as low as possible electric conductivity. However, at the same time it is also important to use a material with favorable mechanical properties in particular with respect to tensile stress. In particular, care is to be taken to provide for sufficiently high tensile strength and sufficient plastic strain capacity as otherwise the centrifugal forces arising can be taken up by very voluminous bandages only. Some metals have proven particularly advantageous in this respect, e.g. titanium and titanium alloys, respectively, as well as stainless steel. The wire-like structure 20 therefore is made of such metals in currently preferred embodiments. As a matter of principle, a nonmagnetic material should be selected for the wire-like structure 20 , in order not to affect the magnetic flux in the air gap. Titanium and its alloys meet this property. Also most of the stainless steels have a sufficiently nonmagnetic behavior in the range of magnetic field strengths of interest here.
[0089] A completely different approach consists in making the wire-like structure 20 from a material having ferromagnetic properties. A ferromagnetic material, as compared to a vacuum, has a high magnetic permeability or magnetic conductivity. Examples of ferromagnetic materials are a number of steels, including stainless steels with material numbers 1.4016 and 1.4511 or ferrous metals such as Fe, Ni, Co and alloys thereof. The advantage hereof is that an additional bandage 18 disposed in the air gap between rotor 10 and stator does not result in a significant increase in the magnetic distance between the mutually opposite poles on rotor and stator. Rather, a bandage 18 consisting of ferromagnetic material has the result that the magnetic flux in bandage 18 takes place with less reluctance. This effect can be exploited for passing the magnetic flux between the poles of rotor and stator more effectively and to thus compensate for the increase in the distance between the poles of rotor and stator that is caused by insertion of the bandage 18 . In certain embodiments, the bandage 18 may even be designed as an extension of the rotor 10 . The magnetically effective distance in the air gap (i.e. the magnetic distance to be bridged by the magnetic flux between rotor and stator) then is as large as or only slightly larger than in a design without bandage 18 . The outer circumference of the rotor then may be virtually equated with the outer circumference of the bandage 18 , which in FIG. 2 is indicated by numeral 12 ′.
[0090] In order to possibly avoid magnetic short-circuiting, the bandage in the respective intermediate portions between the poles of the machines, if possible, should not be ferromagnetic, or should at least be less ferromagnetic, i.e. should have a magnetic permeability as low as possible and thus high reluctance to magnetic flux. The size of the intermediate portions is determined by the poles of the electric machines, i.e. by the stator windings and optionally by the permanent magnets on the rotor in case of an electric machine excited by permanent magnets. Such a bandage can be obtained e.g. by providing the wire-like structure 20 —already prior to winding the same onto rotor—in alternating manner with portions having a ferromagnetic effect (magnetic permeability much higher than one) and portions having an inferior ferromagnetic effect (magnetic permeability in the order of one). The first portions with ferromagnetic properties are arranged mutually spaced apart such that, in winding the same onto rotor 10 , they correspond to the distance between the poles of the machines and, in case of a machine excited by permanent magnets, thus come to lie on the permanent magnets 16 of the rotor, while in the intermediate spaces between the poles, e.g. the permanent magnets 16 or the stator winding, the bandage material shows no or an inferior ferromagnetic behavior. To this end, there may be provided a corresponding pretreatment of the wire-like structure 20 in which individual, mutually spaced apart portions of the wire-like structure 20 —which is made of corresponding ferromagnetic material—are rendered less ferromagnetic.
[0091] Such influencing of the magnetic properties can be implemented by suitable mechanical treatment of the portions concerned. A heat treatment is also feasible as an alternative or in addition. For forming the bandage, it is also possible to use a substantially nonmagnetic wire material which in the desired first portions, i.e. in the region of the rotor poles, has ferromagnetic material applied thereto in addition.
[0092] After the pretreatment, the length of the individual first portions of the wire-like structure 20 with ferromagnetic properties should correspond to the circumferential direction of a permanent magnet 16 on the rotor or the extent of the stator windings, respectively, and the length of the second portions between the ferromagnetic first portions should correspond to the extent of an intermediate portion between the permanent magnets 16 in circumferential direction or to the distance between adjacent stator windings, respectively. As an alternative, it is also possible that a wire-like structure 20 of a ferromagnetic material, during winding the same onto rotor 10 , is actively transformed to a non-ferromagnetic or at least less ferromagnetic state in the respective portions located between two adjacent permanent magnets 16 on the rotor or stator windings, respectively.
[0093] In all of the modifications mentioned it is particularly effective when the wire-like structure 20 , in the portions associated with permanent magnets 16 or stator windings, respectively, are magnetized in such a manner that the preferred direction of magnetization points in the radial direction. To this end, the wire-like structure 20 can be made of a corresponding anisotropic ferromagnetic material.
[0094] FIG. 2 shows a highly simplified schematic sectional view along the rotor axis A, illustrating half of a rotor 10 provided with a multi-layer wire-wrap bandage 18 according to any embodiment. The multi-layer bandage 18 consists of several layers 32 a , 32 b , 32 c of the wire-like structure 20 . Each layer is constituted by a plurality of side-by-side or juxtaposed sections of the wire-like structure 20 . The wire-like structure 20 is wound such that the individual juxtaposed sections within a layer extend parallel to each other and that only spaces as small as possible are left between the juxtaposed sections. The winding direction is substantially parallel to a plane orthogonal to rotor axis A. The winding of the individual layers 32 a , 32 b , 32 c with respect to each other is such that the wire sections of all layers extend parallel to each other and the wire sections of one layer each are offset to the adjacent wire sections of the respective layer above and below, respectively. In this manner, a tightest-possible packing of the individual wire sections can be obtained and thus, with a given number of windings of the wire-like structure 20 around rotor 10 , the thickness of the bandage 18 in its entirety can be kept as small as possible.
[0095] It is also possible to produce a wire-wrap bandage 18 with multi-layer winding of wire-like structure 20 similar to that illustrated in FIG. 2 , in which the individual layers 32 a , 32 b , 32 c are wound with slightly different winding angles with respect to a plane orthogonal to rotor axis A, e.g. with two alternating winding angles in the respective successive layers 32 a , 32 b , 32 c . The individual layers 32 a , 32 b , 32 c then are each wound at an angle in mirror symmetry with respect to the plane orthogonal to the rotor axis A. In this manner it is possible to comply with different requirements holding in subsequent operation of the rotor 10 . For example, the individual layers 32 a , 32 b , 32 c can be optimized with respect to different thermal conditions which the rotor 10 will be subject to later on. It is also possible to wind the individual layers 32 a , 32 b , 32 c from different wire-like structures 20 (in particular wire-like structures 20 of different materials and/or wire-like structures of different diameters).
[0096] FIG. 3 shows a highly simplified illustration of a rotor 10 provided with a wire-wrap bandage 18 according to an embodiment. The drawing reveals the parallel arrangement of the juxtaposed winding sections of the wire-like structure 20 at the outer circumference of rotor 10 having a winding angle substantially parallel to a plane orthogonal to rotor axis A. Moreover, feeding of the wire-like structure 20 to the rotor 10 in the section 20 a between rotor 10 and wire guide means 26 can be seen.
[0097] Finally, FIG. 4 shows a highly simplified sectional view across the rotor axis A, illustrating a rotor 10 provided with a multi-layer wire-wrap bandage 18 according to an embodiment. The rotor 10 is an internal rotor and has on its outer circumference a plurality of circumferentially successive permanent magnets (only some thereof bearing numeral 16 in exemplary manner). The permanent magnets 16 in general have the shape of parallelepipeds. The surface thereof directed outwardly in the installed position has a substantially planar shape. The magnets 16 thus are not ground to a common outer diameter, but constitute a succession of prism surfaces extending in circumferential direction. This is shown in the sectional view of FIG. 4 as a surrounding polygonal succession of the outsides of the permanent magnets 16 . The wire-like structure 20 is wound directly on the prism surfaces 34 and thus forms a wire-wrap bandage 18 of annular outside circumference. Due to the bias of the wire-wrap bandage 18 , the permanent magnets 16 are safely held against centrifugal forces occurring during operation. Round grinding of the permanent magnets 16 to establish the outer surface of the rotor 10 is not necessary.
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The invention relates to a method of producing a rotor ( 10 ) of an electric machine, the rotor ( 10 ) comprising a rotor body ( 14 ) adapted to be rotated about a rotor axis (A) as well as at least one rotor component ( 16 ) to be mounted to the rotor body ( 14 ), said method comprising the steps of: arranging the rotor component ( 16 ) on the rotor body ( 14 ) and winding a wire-like structure ( 20 ) around an outer circumference ( 12 ) of the rotor body having the rotor component ( 16 ) arranged thereon so as to form a bandage ( 18 ), with the wire-like structure ( 20 ) during winding thereof being held under an adjustable bias.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to image reproduction machines, such as printers and copiers, and more particularly relates to paper feed apparatus for such machines.
2. Description of Related Art
In conventional image reproduction machines such as, for example, laser printers, cut paper sheets to be imprinted with the reproduced image are fed through printing means within a housing portion of the machine, and then discharged from the housing into an external paper receiving well formed in the housing. In a laser printer, these printing means include a rotating photoconductive drum from which toner, in the pattern of the image to be reproduced, is electrically transferred onto the moving sheet. As is moves away from the drum, the sheet is passed through a fuser structure which, by a combination of heat and mechanical pressure, fuses the applied toner to the sheet.
Upon exiting the fuser structure the sheet is guided through a curved path, typically around a guide roller, to a spaced plurality of exit roller sets that frictionally drive the imprinted sheet through and then horizontally discharge it, in a forward direction, from a horizontally elongated housing outlet opening into the paper receiving well. The bottom side of the well typically has a horizontal paper support surface spaced forwardly apart and downwardly offset from the outlet opening. Extending rearwardly from the back edge of this horizontal paper support surface is a rearwardly and downwardly ramped surface forming a rearward extension of the horizontal support surface.
The exit roller sets each comprise a rotationally driven resilient roller that pinches the sheet against an idler roller whose axis is upwardly and rearwardly offset from the axis of the driven roller. In theory, the exit roller structure of the printer is positioned relative to the overall bottom side of the receiving well in a manner such that a leading edge portion of the first discharged sheet clears the depressed rear area of the well before its natural downward bend causes it to contact and slide forwardly along the horizontal support surface as the balance of the sheet is discharged from the housing outlet opening.
When the first sheet is fully discharged, a rear end portion thereof bends downwardly into the depressed rear well area and comes to rest on the ramped bottom side surface thereof. Each subsequently discharged sheet follows this discharge sequence, but contacts the previously discharged sheet instead of contacting the bottom side surface of the well, so that a bent stack of discharged sheets is progressively formed in the well area of the housing.
While this is the intended discharge path of each imprinted sheet, a potential paper curling problem can distort the discharge path of the sheets such that they simply roll up in the depressed rear well area, thereby preventing the intended bent stacking of the discharged sheets. This paper curling problem is particularly pronounced in instances where relatively light weight paper is being used, and where there is a sharp guide path bend at the exit of the fuser structure, and can cause the leading edge of the first exiting sheet to bend downwardly to an extent that it strikes the ramped well surface instead of the horizontal well surface in front of it.
When this occurs, the sheet simply bends into a rolled configuration and undesirably remains in the depressed well area. The leading edges of successively discharged sheets similarly strike the ramped well surface, or previously rolled sheets as the case may be, and quickly build up to block the paper discharge path.
One previously proposed solution to this problem has been to radially enlarge one relatively thin end portion of each of the driven exit rollers so that as each sheet is pinched between and driven forwardly by the exit roller sets these radially enlarged roller end portions form on the underside of the driven sheet relatively small corrugation lines along the entire length of the sheet. This permanent corrugation of the sheet tends to stiffen it sufficiently so that as it is discharged from the printer housing its leading edge clears the ramped well surface and properly lands on the horizontal well surface in front of it, thereby forming the desired bent stack of discharged sheets in the well area instead of forming a disorderly array of rolled sheets in the depressed rear well portion.
While this permanent sheet corrugation method tends to solve the aforementioned paper curling problem, it often creates a new problem--namely, the "crinkling" of the sheets as they are discharged from the printer housing outlet opening. Specifically, by positioning the thin, disc-shaped corrugating structures immediately adjacent the paper "pinch" zones of the exit roller sets, the sheets are subjected to relatively large side-to-side shortening forces at the points at which they traverse the "nip" areas of the exit roller sets. Accordingly, longitudinal portions of the sheets are forcibly caused to slide longitudinally within the nip areas of the roller sets, thereby crinkling the sheets.
Another limitation commonly associated with conventionally configured image reproduction machines, such as the laser printer discussed above, relates to the maximum number of discharged sheets that may be stacked in the aforementioned bent configuration in the housing well area before the stack blocks the external paper discharge path and must be removed from the well. It will be appreciated from the general well geometry described above that the rear edge of the horizontal bottom well surface must be close enough to the housing outlet opening to assure that the leading edges of the discharging sheets forwardly clear such rear edge before they bend down to a level below that of the horizontal well surface. Otherwise, the previously described sheet roll-up problem will occur.
Of course, the closer this rear edge is positioned to the housing outlet opening, the less likely it is that such roll-up will occur. However, as this rear edge is moved closer to the outlet opening a corresponding decrease in the minimum distance between the ramped well surface and the outlet opening also occurs. While the available stack height directly above the horizontal surface of the open-topped well is not theoretically limited, the maximum number of discharged sheets that may be stacked in the well is limited by this distance between the ramped well surface and the outlet opening. Specifically, as the discharged paper stack grows, at some point the bent rear portion of the top sheet interferes with the discharge of the next sheet, and the stack must be removed from the well before subsequent sheets can be discharged thereto.
In printers, and other types of image reproduction machines having this conventional well and paper discharge design, the optimal front-to-rear placement of the rear edge of the horizontal well surface tends to result in an outlet opening-to-ramped well surface dimension which limits the maximum number of discharged sheets that can be received in the well area to a number less than 500 (i.e., the number of cut paper sheets in a standard one ream package). As an example, a conventional printer of the general type described above typically has a discharge stack capacity of from about 425 to about 450 sheets--i.e., a number substantially short of a more desirable 500 sheet stack capacity.
Another problem that conventional printers and other types of image reproduction machines of this well configuration tend to have is related to their pivotally mounted paper output sensor member that is positioned outwardly adjacent the housing outlet opening and functions to monitor the number of sheets in a given discharge stack thereof. The sensor, typically a small plastic molding, is pivoted upwardly by each discharged sheet and then pivots downwardly to rest upon the top side of the stack until this pivot cycle is initiated again by the next discharged sheet. Particularly when the discharged paper stack is relatively thick, the sensor is subject to being forced upwardly and broken by the stack as the stack is removed from the well by lifting it upwardly and rearwardly therefrom.
It can readily be seen from the foregoing that it would be desirable to provide an image reproduction machine of the general type described with paper discharge apparatus that eliminates or at least substantially reduces the above mentioned discharge problems, limitations and disadvantages. It is accordingly an object of the present invention to provide such apparatus.
SUMMARY OF THE INVENTION
In carrying out principles of the present invention, in accordance with a preferred embodiment thereof, an image reproduction machine generally as described in the preceding section is provided with specially designed paper deflector apparatus that uniquely functions to (1) essentially eliminate the aforementioned paper curling problem without causing appreciable crinkling of the image-imprinted sheets, (2) increase the maximum number of discharged sheets that may be operatively stacked within the housing well area, without altering the well geometry, and (3) protect the pivoted paper output sensor from damage or breakage by the paper stack as the stack is removed from the housing well area.
The image reproduction machine, representatively a laser printer, is provided with a horizontally spaced series of exit roller sets positioned at the printer housing outlet opening. Each exit roller set includes a relatively large diameter resilient drive roller laterally pressed against a smaller diameter along a paper nip area horizontally aligned with the nip areas of the other exit roller sets, along which a discharging paper sheet is frictionally gripped as the exit roller sets drive the sheet outwardly into the open-topped well area through the housing outlet opening.
The paper deflector apparatus, in a preferred embodiment thereof, is removably attachable to the printer above the exit roller sets and is provided with a plurality of first depending deflector means that are interdigitated with the exit roller sets. Each of these first depending deflector means has a bottom surface area centrally positioned between an adjacent pair of exit roller sets at a level somewhat lower than those of the roller set nip areas. As each successively discharged sheet is gripped by and driven through the exit roller sets, the bottom surface areas of the first depending deflector means contact and downwardly bend portions of the sheet disposed between adjacent pairs of the exit roller sets.
Such downward bending causes the discharging sheet to temporarily assume a corrugated configuration as it exits the roller sets. This serves to momentarily stiffen the sheet, as its leading edge forwardly approaches the rear edge of the horizontal bottom surface portion of the receiving well, and prevent its leading edge from striking the ramped well surface and causing the sheet to roll up in the rear well depression. Importantly, the first depending deflection means are configured, and positioned relative to the exit roller sets, in a manner such that the temporary sheet corrugations have a rather gentle curvature which, coupled with a relatively large sheet contact surface of each of the deflection means, serves to prevent both creasing and sideways crinkling of the discharging sheet.
The paper deflector apparatus is also provided with a spaced plurality of second depending deflector means having bottom surface portions positioned somewhat above the bottom surface portions of the first depending deflector means. As a rear top side edge section of the discharged paper stack portion within the depressed rear well area begins to upwardly approach housing outlet opening, the second depending deflector means function to downwardly engage each successively discharged sheet in a manner forcing a leading edge portion thereof against a rear edge portion of the previously discharged sheet on the top of the stack. The contact by the discharging sheet with the underlying sheet causes the underlying sheet (and one or more sheets beneath it) to be forwardly offset relative to the discharging sheet after it exits the housing outlet opening and comes to rest on top of the balance of the paper stack.
This frictional forward shifting effect is repeated by each successively discharged sheet, by the action thereon of the second depending deflector means, in a manner causing an uppermost portion of the stacked sheets to be progressively staggered in a forward direction relative to one another. This forward relative staggering of the uppermost stack sheets serves to diminish the stack depth adjacent the housing outlet opening relative to the stack depth over the horizontal bottom side surface of the housing well area.
The effect of such stack depth reduction adjacent the housing opening is to advantageously increase the total number of discharged sheets that may be operatively stacked in the well area before the sheets must be removed to clear an external discharge path for a new batch of sheets. In an illustrated embodiment of an image reproduction machine provided with the paper deflector apparatus of the present invention, the nominal 450 sheet discharge stacking capacity of the machine is increased to at least 500 sheets, thereby providing the machine with a convenient one ream paper feed batch capacity.
In a preferred embodiment thereof, the paper deflector apparatus is a molded plastic plate member having an elongated rectangular configuration having a longitudinally spaced plurality of clip portions formed on its bottom side surface and permitting the deflector plate to be removably clipped onto a support bar portion of the machine that overlies the housing outlet opening. The aforementioned first and second depending deflector means are formed on the clip portions.
According to another feature of the present invention, the leading side edge of the deflector plate has a small notch formed therein. The notch is positioned and configured to receive an outer end portion of the paper output sensor member as it is upwardly pivoted by contact with the paper stack as the stack is lifted upwardly and rearwardly out of the housing well area. The receipt of the outer end portion of the paper output sensor member in the deflector plate notch serves to limit the upward pivotal motion of the member, and limit the upward bending forces thereon, to thereby protect the member from damage or breakage by the paper stack as the stack is lifted from the well area.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 (Prior Art) is a schematic partial cross-sectional view through a conventional laser printer illustrating a portion of its paper feed path, and depicting a potential curling problem associated with an image-imprinted paper sheet being discharged from its housing outlet opening;
FIG. 2 (Prior Art) is a schematic side elevational view of a pair of conventional printer exit roller sets provided with radially enlarged corrugating end portions in an attempt to solve this paper curling problem;
FIG. 3 is a top side perspective view of a paper discharge deflector plate structure embodying principles of the present invention;
FIG. 4 is a bottom side perspective view of the deflector plate structure;
FIG. 5 is an enlarged scale cross-sectional view through the printer illustrating the deflector plate structure operatively attached thereto and functioning to nonpermanently corrugate and temporarily stiffen a paper sheet being discharged from the printer housing outlet opening;
FIG. 6 is a cross-sectional view through the discharging sheet, taken along line 6--6 of FIG. 5, schematically illustrating the unique paper corrugating and stiffening action of the deflector plate structure;
FIG. 7 is a horizontally foreshortened cross-sectional view through the printer, similar to that shown in FIG. 5, schematically illustrating a paper stack height increasing feature of the deflector plate structure; and
FIG. 8 is an enlarged scale perspective view of a portion of the deflector plate structure illustrating the manner in which it protects the printer's pivotable paper output sensor member against damage or breakage as a discharged paper stack is lifted out of the paper receiving well area of the printer.
DETAILED DESCRIPTION
Cross-sectionally illustrated in simplified form in FIG. 1 (Prior Art) is a conventional image reproduction machine representatively in the form of a laser printer 10. Printer 10 has a housing 12 provided with an open-topped discharged paper receiving well area 14 positioned forwardly (i.e., rightwardly) of a horizontally elongated housing outlet opening 16. Well 14 has a horizontal bottom side surface 18 which is forwardly and downwardly offset from the outlet opening 16, and a downwardly and rearwardly ramped surface 20 extending rearwardly from the back edge 22 of surface 18 and forming the front boundary of a depressed rear end area 23 of the well.
Positioned immediately above the outlet opening 16 is an elongated metal support bar 24 that extends parallel to the outlet opening and overlies three horizontally spaced exit roller sets 26. Each exit roller set 26 includes a resilient drive roller 28 connected to a drive shaft 29, and a smaller diameter idler roller 30 pressed downwardly against the drive roller and rearwardly offset relative thereto.
The exit roller sets 26 form a portion of paper feed means that are operative to drive successive cut paper sheets, such as the illustrated sheet 32 through the housing 12, along a dotted line feed path P, and then forwardly discharge the sheets into the well area 14 in a manner such that they come to rest therein in a stack S. In the stack S, front portions F of the sheets rest upon the horizontal well surface 18, with rear portions R of the sheets being downwardly bent into the depressed well area 14a and supported on its ramped rear surface 20.
The paper feed path P is bounded on opposite sides thereof by conventional guide structures, such as the schematically depicted structures 34 and 36, that serve to define the path. As each successive sheet is operatively fed through the housing 12 along path P, it sequentially passes between a rotating photoconductive drum 38 and a corotron unit 40, through a fuser unit 42, around a guide roller 44, and into the nip areas N between the contacting drive and idler roller pairs 28,30.
As each sheet passes between the drum 38 and the corotron unit 40, toner deposited on the drum in a predetermined image pattern controlled by a laser L beamed onto the drum, is electrically transferred onto the sheet by the corotron. The transferred toner is then fused onto the sheet, by a combination of heat and mechanical pressure, by the fuser unit 42 as the sheet is passed therethrough on its way to the nip areas N of the exit roller sets 26.
The printer 10 is conventionally designed and configured in a manner such that as each imprinted sheet 32 is forwardly discharged through the housing outlet opening 16, while the discharged sheet portion naturally bends downwardly due to its weight, the leading sheet edge portion 46 will upwardly and forwardly clear the back well surface edge 22 and then contact and slide forwardly along the horizontal well surface 18 (or the top side of stack S as the case may be) until the remainder of the sheet is discharged and falls downwardly into the depressed rear well area 23.
In this conventionally designed printer, a paper curling problem can arise--particularly when relatively light weight paper is being used--due to the relatively sharp paper exit bend at the fuser 42 that tends to "set" a curl in each sheet exiting the fuser. This curling tends to accentuate the downward bending of the sheet 32, as it exits the housing outlet opening 16, to an extent that its leading edge portion 46 strikes the ramped well surface 20 (or the downwardly bent rear stack portion as the case may be), thereby causing the sheet 32 to simply roll up in the depressed well area 23 as indicated in dotted lines in FIG. This occurrence, of course, prevents the desired orderly stack S from being formed, and greatly reduces the number of sheets that can be discharged from the housing 12 is a given printing batch.
A conventional solution to this paper curling problem is shown in simplified form in FIG. 2 (Prior Art) and involves the placement of radially enlarged corrugating discs 48 on one end of each of the drive rollers 28 closely adjacent its associated nip area N. As the sheet 32 is forwardly discharged from the exit roller sets 26, the discs 48 form relatively sharp corrugating bends 50 in the sheet along its entire length. These sharp corrugating bends 50 tend to stiffen the discharging sheet to an extent counteracting the undesirable sheet curl sufficiently to cause the leading sheet edge portion to upwardly and forwardly clear the back well surface edge portion 22 as intended.
The paper stiffening achieved by the thin corrugating discs 48, however, tends to create two new paper handling problems. First, the sharp corrugating bends created closely adjacent the nip areas N tend to undesirably form small but permanent crease lines along the length of the sheet. Second, the positioning of the corrugating structures immediately adjacent the nip areas N tends to impose substantial lateral shortening forces on the sheet as it traverses the nip areas. These shortening forces can cause portions of the sheet to longitudinally slide along the nip areas, as indicated by the arrows 52 in FIG. 2, thereby permanently crinkling the discharging sheets.
Turning now to FIGS. 3 and 4, these paper feed problems are uniquely solved by the provision and attachment to the laser printer 10 (or to another type of image reproduction machine having a similarly configured paper discharge portion) of exiting paper deflector apparatus that embodies principles of the present invention. In the illustrated preferred embodiment thereof, the apparatus is in the form of a molded plastic deflector bar 60 having an elongated rectangular base portion 62 with a length approximately equal to the horizontal length of the support bar 24 (FIG. 1).
Base portion 62 has a top side 64; a bottom side 66; a slightly downturned rear side edge 68; a front side edge 70; and a pair of opposite end edges 72 and 74. For purposes later described, a small rectangular notch 76 is formed in the front side edge 70. A longitudinally spaced series of two outboard clips 78 and two inboard clips 80 are formed on front edge portions of the underside of the base portion 62 beneath and downwardly offset from rectangular molding openings 82 therein. Each of the clips 78,80 extends rearwardly from its connection to the base portion 62, has a free rear end 84, and defines with the underside of the base portion 62 a rearwardly opening slot 86 that is forwardly bounded by a longitudinally extending transverse rib 88 projecting outwardly from the bottom side 66 of the base portion 62.
As can best be seen in FIG. 4, depending from the underside of each of the two outboard clips 78 are three spaced apart ribs 90 having rear end surfaces 92 forwardly offset from the rear ends 84 of clips 78, and aligned, forwardly and downwardly sloping bottom side edge surface 94. Depending from the underside of each of the inboard clips 80 are three spaced ribs 96 having rear end surfaces 98, the central surface 98 being aligned with the clip end 84, with the two outboard surfaces 98 in each three rib set being forwardly offset from their associated clip end 84.
For purposes later described, rear portions 100 of the bottom side edge surfaces of ribs 96 are parallel to the bottom side surface 66 of base portion 62 and are deeper in a downward direction than the ribs 90 on the outboard clips 78. Front end portions 102 of the bottom side edges of the ribs 96 are aligned with and sloped identically to front end portions of the bottom side edge surfaces of the ribs 90 on the outboard clips 78.
Turning now to FIG. 5, portions of an improved laser printer 10a are cross-sectionally illustrated in somewhat schematic form. Printer 10a is identical to the conventional printer 10 previously described in conjunction with FIG. 1 except for the addition thereto, in a manner subsequently described, of the specially designed paper deflector bar 60 of the present invention. For ease in comparison between the improved printer 10a and the conventional printer 10, components in printer 10a similar to those in printer 10 have been given identical reference numerals with the subscripts "a".
The deflector bar 60 is removably installed on the support bar 24a simply by inserting the leading front edge of the support bar 24a into the clip slots 86 (see FIG. 4) and then pushing the deflector bar rearwardly onto the support bar until the leading edge of the support bar bottoms out against the elongated bottom side rib 88 of the base portion 62 of the deflector bar. The downturned rear side edge 68 of the base portion 62 serves to frictionally retain the deflector bar 60 in place on the support bar 24a.
As best illustrated in FIG. 6, with the deflector bar 60 removably installed in this manner, the two sets of outboard ribs 90 are spaced outwardly apart from the horizontally outer exit roller sets 26a(1) and 26a(3) and are spaced slightly upwardly apart from the nip areas N. Each of the two sets of inboard ribs 96 are centrally positioned between one of the two adjacent exit roller set pairs 26a(1),26a(2) and 26a(2),26a(3), with the deepened rear portions 100 of ribs 96 (see FIG. 5) being somewhat downwardly offset relative to the nip areas N.
As the sheet 32 is forwardly discharged outwardly through the housing outlet opening 16a, the deepened rear portions 100 of the depending deflector ribs 96 downwardly contact and bend lateral portions of the sheet centrally disposed between the adjacent exit roller set pairs 26a(1),26a(2) and 26a(2),26a(3) to form corrugation areas C in the discharging sheet. These corrugation areas C in the sheet 32 serve to stiffen the sheet as it passes over the depressed housing well area 23a, thereby permitting the leading sheet edge portion 46 to upwardly and forwardly clear the rear well surface edge portion 22a to cause sheet 32, and subsequently imprinted and discharged sheets to stack properly in the well area 14a.
Importantly, due to their central positioning between adjacent pairs of exit roller sets, and their relatively wide undersurface areas that contact the sheet 32, the deepened rear portions 100 of the inboard rib sets 96 cause the corrugation areas C to assume a rather gentle downward curvature and to progressively dissipate as the sheet is discharged. Because of these temporary sheet corrugation and stiffening characteristics provided by the ribs 96, the sheet 32 is not permanently creased, and does not have a tendency to laterally crinkle, as it passes through the exit roller sets 26a. It can readily be seen that this provides a substantial improvement over the conventional sheet corrugating and stiffening structure shown in FIG. 2.
Referring now to FIGS. 1 and 7, the installed deflector bar 60 provides the improved laser printer 10a with another desirable feature, provided by front underside portions of the depending deflector ribs 90 and 96, namely the ability to operatively stack a substantially larger number of sheets 32 in the housing well area 14a, during a given printout batch, than can be accommodated in the identically configured well area 14 of the conventional printer 10 shown in FIG. 1.
As a rear top side portion of a discharged paper sheet stack S upwardly approaches the housing outlet opening 16 in the conventional printer 10, rear edge portions of the uppermost sheets in the stack will begin to block the external paper discharge path of the printer, thereby requiring the printing to be stopped until the stack is removed from the well area. Typically, in the illustrated conventional printer 10, this event occurs when about 450 or so discharged sheets (i.e., a number of sheets substantially less then the 500 sheets in a standard one rear package) have been stacked in the housing well area.
In the representative improved printer 10a, however, 500 or more discharged sheets 32 may be operatively stacked in the well area 14a at one time as will now be described with reference to FIG. 7. As the number of discharged sheets 32 in stack S increases, the top side of a rear portion of the stack begins to upwardly approach the housing outlet opening 16a. When this occurs, the front edge portion 32f of the discharging sheet 32 is downwardly contacted by front undersurface portions of the depending deflector ribs 90,96 (which are upwardly offset relative to the exit roller nip areas N) in a manner forcing such front edge portion 32 into frictional forward sliding contact with the underlying rear edge portion 32r of the previously discharged sheet 32.
Such frictional sliding contact causes the front edge portion 32f of each underlying sheet 32 in an uppermost stack portion to be forwardly staggered relative to the front edge portion 32f of the next discharged sheet, and also causes a similar front-to-rear staggering of the rear edge portions 32r of the two sheets. This progressive staggering of the rear end portions 32r in an uppermost section of the stack S uniquely functions to reduce the effective stack height X adjacent the outlet opening 16a in the depressed well area 23a compared to the actual stack height Y above the horizontal bottom well side surface 18a.
In turn, this permits a substantially larger of sheets 32 to be operatively stacked in well 14a than could be operatively stacked in the identically configured well 14 of the conventional printer 10. For example, in the illustrated conventional printer 10, the maximum stack capacity is approximately 450 sheets. With the paper deflector bar 60 installed, however, it is able to operatively stack at least 500 sheets--i.e., a full one ream package of cut paper sheets.
Referring now to FIGS. 1 and 5, the printers 10 and 10a are respectively provided with conventional paper output sensor members 104,104a that are pivoted upwardly and downwardly by the successively discharged sheets 32 as they upwardly contact the sensor member outer end portions 106,106a. In the printer 10, the sensor member 104 is susceptible to being upwardly pivoted and broken off by the paper stack S as the stack is upwardly and rearwardly lifted out of the housing well 14. However, this potential sensor member breakage is essentially eliminated in the improved printer 10a.
Specifically, as shown in FIG. 8, as the sensor member 104a is upwardly engaged and pivoted by the paper stack S during upward and rearward removal of the stack from the well area 14a, the outer sensor member end portion 106a is upwardly received and retained in the front edge notch 76 of the base portion 62 of the deflector bar 60. This safely limits the upper pivotal motion of the member 104a and prevents excessive counterclockwise torque from being imposed thereon by the paper stack as it is being lifter out of the housing well area 14a.
The foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims.
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An image reproduction machine has an outlet opening through which successive image-imprinted paper sheets are forwardly discharged by a spaced series of exit roller sets. The discharged sheets are delivered into an open-topped housing well area having a horizontal bottom surface with a back edge forwardly and downwardly offset from the outlet opening, and a ramped surface extending downwardly and rearwardly from the horizontal surface back edge. A deflector bar adjacent the outlet opening has first downwardly projecting portions that engage each discharging sheet and temporarily corrugate and stiffen it in a manner assuring that its front end portion will forwardly clear the rear horizontal surface edge before bending down to its level. These downwardly projecting portions are interdigitated with the exit roller sets and positioned to perform their temporary corrugation function without crinkling the discharging sheets. The deflector bar is also provided with second downwardly projecting portions that function, as the stack nears its maximum height, to cause each successive discharging sheet to engage the previously discharged sheet in a manner forwardly advancing and staggering the uppermost sheets. This reduces the effective stack height adjacent the outlet opening to thereby permit a greater number of discharged sheets to be stacked in the well before the stack blocks the external sheet discharge path. A notch in the deflector bar serves to receive and protect the pivoted paper output sensor portion of the machine as the stack is removed from the well.
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[0001] This patent is a U.S. national application of PCT international application no. PCT/IB99/01996, filed Dec. 13, 1999, which claims the right of priority to and benefit of the earlier filing date of Great Britain application serial no. 9827646.2, filed Dec. 17, 1998.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to support devices for portable apparatus such as cameras, microphones, telescopes, surveying equipment and the like.
[0004] 2. Description of the Related Art
[0005] Many devices are known for the mounting of cameras and like articles on flat surfaces, windows, railings, etc. However, the devices are generally bulky and complex and have limited mounting capabilities.
[0006] U.S. Pat. No. 5,055,864 describes a portable camera support comprising a bracket which is intended to provide a stable platform for a camera in window openings, for example of a motor vehicle. However, this bracket would not be appropriate for mounting a camera on a flat surface or on a curved surface such as a railing. U.S. Pat. No. 4,439,032 describes a portable camera support which utilizes a strap which passes around a railing or tree and which is intended to mount a camera firmly thereon.
[0007] International Publication no. WO-A-98/39178 describes a pedestal for stable support of a variety of equipment, for example a camera, and which comprises two limbs which can be used to either stand the support on a surface e.g. a table, or hang the support from a vertical member, e.g. a vehicle window. It is however extremely bulky.
[0008] Great Britain Patent No. 2,272,834 describes a camera support that is more versatile in terms of how it can be used, but it is relatively complex in terms of the large number of parts. It is essentially a tripod that is separable to offer greater possibilities for the support to be mounted elsewhere than on flat surfaces.
[0009] U.S. Pat. No. 3,908,945 is directed to a portable camera mounting apparatus having a hollow telescopic body structure for supporting a camera. The body structure includes, among other features, support legs that can be detachably mounted to the body structure. This device is limited to support articles on a substantially horizontal surface, such as a table, floor, or the ground.
[0010] It is therefore an object of the present invention to provide a support for cameras and like articles which is extremely versatile in terms of its mounting and supporting capabilities, yet which is extremely compact and composed of relatively few components.
SUMMARY OF THE INVENTION
[0011] In accordance with the present invention there is provided a support device for cameras and like articles which comprises a base member, at least one mounting means for support means removably carried by the base member for mounting of a camera or like article thereon, and a plurality of support legs detachably mounted to the base member to project therefrom in a plurality of different selected orientations relative to the base member. The various orientations may be selected to establish a plurality of different selected support functions and orientations for the support device, whereby a support device that is versatile in use is obtained.
[0012] Preferably the support legs are securable to the base member through screw-threaded members with the respective female members being formed in the base member, preferably threaded holes whose axes are orientated along a plurality of different directions, preferably in at least three orthogonal directions.
[0013] The support legs when not performing the support function may be carried in bores in the base member in a non-functional position. The bores add rigidity to the base member and reduce the weight thereof. Preferably the legs are retained in the bores by being screwed into threaded portions of said bores. Preferably, four support legs are provided with the base member each being housed in a respective bore.
[0014] The base member is preferably provided with a recess in its underside, and with slots there through, to enable the base member to be secured by tie means passed through the slots to an elongate supporting member, such as a rail, a pole, a post or the limb of a tree, which is positioned in the recess. The recess may have a substantially ‘V’ shaped or generally arcuate cross-section and its surface may be provided with a non-slip surface by, for example, being ribbed or knurled.
[0015] These variations, modifications, and alterations of the various preferred embodiments and methods may be used either alone or in combination with one another as will become more readily apparent to those with skill in the art with reference to the following detailed description of the preferred embodiments and the accompanying figures and drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0016] In order that the invention may be more fully understood, one presently preferred embodiment of camera support in accordance with the invention will now be described by way of example and with reference to the accompanying drawings in which:
[0017] [0017]FIG. 1 is a schematic plan view of the support device;
[0018] [0018]FIG. 2 is a schematic view from one end of the support device shown in FIG. 1 taken in the direction of the arrow denoted by reference numeral II in FIG. 1, with the support legs removed;
[0019] [0019]FIG. 3 is a schematic view of the support device, taken from the other end and in the direction indicated by the arrow denoted by reference numeral III in FIG. 1, with the support legs removed;
[0020] [0020]FIG. 4 shows one of the support legs of the device; and
[0021] [0021]FIG. 5 is a side view of the body member taken in the direction of arrow denoted by reference numeral V in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0022] According to the present invention, a support device is shown in the drawings that may be used with cameras or other optical equipment. The device has a base member 10 made from any suitable material such as engineering plastics material such as polyamide, acetal resin, thermoplastic polyester or a metal such as aluminum or die cast zinc. The base is shaped somewhat in the manner of a bridge, as can be seen most clearly from FIGS. 2 and 3. The base member 10 has a top portion 12 with end walls 13 , 13 a and side portions 15 , 15 a . The top portion 12 is provided with a threaded hole 11 (FIG. 3) forming a mounting means for a like screw-threaded stud shaft of a removable support-and-tilt assembly 16 and which will be described in more detail hereinafter.
[0023] The top portion 12 of the base member is provided with a pair of parallel slots 18 which extend in the longitudinal direction almost the full length of and through the thickness of the base member.
[0024] One side portion 15 a has an outwardly projecting integral lug 24 with a keyhole-shaped hole 26 there through. The lug 24 enables the support device to be hung by lug 24 from a wall fixing e.g. a screw, nail or pin.
[0025] As shown most clearly in FIGS. 2 and 3, the underside 66 of the base member is provided with a substantially ‘V’ shaped or generally arcuate recess 29 . The recess 29 comprises two ribbed surfaces 28 inclined at about 120 degrees or arc to each other. The ribbed surfaces provide grip to enable the support device to be mounted on an elongate supporting member such as a rail, a pole, a post or the limb of a tree, as indicated in broken outline at 30 in FIG. 2. The support device would be fixed to the supporting member 30 by the use of a flexible strap or tie (not shown) which is threaded through the slots 18 in the base member and around the supporting member 30 . It will be appreciated that with this configuration, supporting members 30 of a wide variety of thicknesses can be accommodated and have the support device held stably or firmly thereto.
[0026] An important feature of the invention is the provision of four support legs 32 , one of which is shown in FIG. 4. Each support leg 32 comprises an elongate stem with a threaded stub 34 at one end. Two resilient rings 36 , for example of rubber or plastics material, are recessed into the stem at spaced intervals along the length of the support leg so to provide a resilient surface which is slightly proud of the surface of the leg. The support legs 32 are normally housed within bores 38 formed in the base member 10 , when the support device is not in use. The bores 38 extend from one end wall 13 to the other end wall 13 a through the main body of the base member. These bores 38 terminate at said other end of the base member, as shown in FIG. 3, in reduced diameter screw-threaded portions or holes 40 . When not in use, the support legs 32 are pushed into the bores 38 (FIG. 2) and have their threaded ends 34 screwed into the threaded holes 40 . The legs 32 may have any desired length but preferably leave only a short portion of the plain end of the support leg 32 projecting from the end of the base member. The non-threaded end portion of the legs 32 may be knurled to facilitate the screwing and unscrewing of the legs.
[0027] The support legs 32 play a key role in the use of the support device. They have a number of different applications, depending upon need. Each corner of the base member 10 is provided with two screw-threaded holes 42 (FIGS. 2 and 3) adjacent to the bottom of the base member. Each of these screw-threaded holes 42 is dimensioned to receive a threaded stub end 34 of a support leg 32 . Thus, as shown in FIG. 1, the support legs 32 can be screwed into the corners of the base member 10 to extend in four directions at right-angles to each other and thus provide a stable support for the support device, preventing it from tilting in any direction. Alternatively, if needed, the support legs 32 can be screwed into the holes 42 in opposite ends 13 , 13 a , or in opposite sides 15 , 15 a of the base member in order to provide greater stability in one direction than in the normal direction. The individual support legs 32 can be used, as necessary, to meet the individual circumstances. Because the holes 42 are adjacent to the bottom of the base member, the support legs 32 , when screwed into place, have their undersides flush with the flat surface on which the base member is positioned. This prevents any wobbling of the unit.
[0028] The support device of the present invention also permits the unit to be mounted stably on for example the window of a motor vehicle, or indeed on any generally upright plate-like member. As described above, the other end 13 a of the base member 10 , shown in FIG. 3, is provided with a plurality of screw-threaded holes 40 , which are each dimensioned to receive the threaded stub end 34 of the support legs 32 . When screwed into place in these holes 40 and in holes 42 , the support legs may define a channel. Such a channel may for example receive the glass of a vehicle window, as indicated schematically at 46 in FIG. 3. As shown, two of the support legs would be positioned on one side of the glass and the other two on the other side, thereby holding the assembly stably on the glass. The resilient annular members 36 on each support leg 32 make contact with the surfaces of the glass and assist in holding the unit securely in place without wobbling.
[0029] In addition to providing the threaded holes 40 , 42 to receive the support legs 32 , the end wall 13 A of the base member can be provided with a slot 23 , as shown in FIG. 3, which extends substantially along the line of the glass indicated at 46 in FIG. 3. Such a slot could open into the slots 18 and thereby extend over a substantial part of the end-to-end dimensions of the base member, i.e. into the plane of the drawing as shown in FIG. 3. The base member 10 would then form a caliper type support and the slot 23 would then receive the window glass or the like, with the legs of the caliper lying each side of the glass and a bridge portion 49 straddling the edge of the window. The slots could be faced with a rubber or plastic material for protection purposes and to prevent vibration. The top portion 12 of the base member may be provided with a screw-threaded bore 19 (FIG. 1) which receives a thumb wheel type clamping screw (not shown) for clamping the body directly to the glass. The clamping screw may have a resilient tip where it engages the glass in order to minimize damage to the clamped surface. Additionally, the base member may be provided with further threaded holes 47 located in the side portions in the bridge portion 49 so that the legs 32 may be positioned to extend parallel to the edge of the window and prevent rocking of the support device in the plane of the glass.
[0030] The support-and-tilt assembly 16 is particularly adapted for the mounting of a camera on the support device. A screw-threaded stub at the bottom of the unit extends from a generally cylindrical rod 48 that has a concentric annular collar 50 . The upper end of the collar 50 houses a ball from which a shaft 58 extends upwards, terminating in a threaded end 60 onto which is screwed a cap 62 . The ball joint that is thereby achieved enables a camera screwed onto the threaded end 60 to be adjusted in position.
[0031] If further height is required for the support device, then the support-and-tilt assembly 16 can be unscrewed from the base member and an extension member can be fitted between the base member and the support-and-tilt assembly 16 . The base member 10 is also provided in said one end wall 13 with a further threaded hole 64 (FIG. 2) into which the support-and-tilt assembly can be fitted as an alternative position, particularly when the device is used as in FIG. 3 for mounting a camera on a window glass, or vertical support such as a rail, a pole, a post or the limb of a tree. Then, the support legs 32 extend downwards, over the glass, and the support-and-tilt assembly extends upwards, facilitating its use.
[0032] In a further embodiment of the support device, the underside of the base member, indicated at 66 in FIGS. 2 and 3, is provided with threaded holes adjacent the corners (not shown) having axes normal to the holes 42 and dimensioned to receive the threaded ends 34 of the support legs 32 . This enables the device to be mounted on an object which is located between the support legs 32 , with the support-and-tilt assembly 16 set in the top surface 12 of the base member, as shown in the drawings. A plurality of spaced holes may be provided to accommodate different sizes of supporting member.
[0033] In another variation a plurality of spaced screw-threaded holes for the legs 32 may be provided in the surface 28 of the recess 29 . These holes may be spaced apart irregularly and have axes inclined at different angles to the surface 28 allowing legs 32 to be screwed at various inclinations into the base member 10 at variable spaced locations so that the legs may act as clamps against smaller diameter articles or elongate supporting members 30 . The screw-threaded portions 34 of the legs 32 may have increased lengths to facilitate this function.
[0034] The support device provides a compact unit which, when in a disassembled condition, with the legs housed in the bores 38 , can be carried in the pocket of the user, and which can be assembled to provide different constructions having different end uses.
[0035] Although the exemplary embodiments of the present invention have been described in detail above, numerous alterations, modifications, and variations of the preferred embodiments disclosed herein will be apparent to those skilled in the art and they are all contemplated to be within the spirit and scope of the instant invention. For example, although specific embodiments, modifications, variations, and examples have been described in detail, those with skill in the art will understand that such can be modified to incorporate various types of substitute and/or additional materials, components, elements, and relative arrangement thereof for compatibility with the wide variety of contemplated uses and equipment available and in use in the related industries. Accordingly, even though only few variations, modifications, and examples of the present invention are described herein, it is to be understood that the practice of such additional modifications and variations and the equivalents thereof, are within the spirit and scope of the invention as defined in the following claims.
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A support device for cameras and like articles that comprises a base member ( 10 ), mounting means ( 11, 64 ) for support means ( 16 ) removably carried by the base member for mounting of a camera or like article thereon, and a plurality of support legs ( 32 ), which are detachably mountable to the base member ( 10 ) to project therefrom in a plurality of different selected orientations relative to the base member and to provide selected support functions. The support legs ( 32 ), when not performing the support function, may be housed in bores ( 38 ) in the base member ( 10 ).
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FIELD OF THE INVENTION
The present invention relates to double containment pipe assemblies wherein an inner or primary pipe is located within an outer or containment pipe, and more particularly, to support apparatus for supporting an inner or primary pipe within an outer or containment pipe.
BACKGROUND INFORMATION
Hazardous fluids are routinely conveyed within enclosed pipes or conduits. Recognizing that such pipes and conduits can leak due to manufacturing defects, excessive pressure, corrosion, and joint defects, for example, which may be due to thermal stresses, double-containment piping systems have been developed in which an inner or primary pipe is located within an outer or containment pipe forming an annulus between the inner and outer pipes. The annulus is typically dry, except in the event of a leak of fluid carried by the inner pipe. The inner pipe is typically supported by resting directly on the lower, inside wall of the outer pipe. Alternatively, support apparatus are provided in which the inner pipe is supported in spaced relation to the inside wall of the outer pipe. Exemplary supports are illustrated in the following U.S. Pat. Nos. 5,141,184; 5,018,260; 4,751,945; 3,863,679; and 3,417,785.
Although such prior supports may be used to support the inner pipe within the outer pipe, and provide ready access to the inner pipe at spaced locations along the outer pipe, such supports are typically joined to the inner pipe and/or the outer pipe by welding or bonding means to secure the support in place. The welding or bonding process can require significant construction and assembly time, which results in added project costs, and further prolongs the installation time of the double-containment piping system. The welding or bonding process also typically requires that the support be made of the same material as either the inner or the outer pipe so that it can be adequately welded or bonded to the respective pipe. Accordingly, any flexibility in selecting the material for the support is frequently limited by the materials of the inner and outer pipes.
Prior supports also frequently directly support an inadequate portion of the inner pipe in comparison to that which is typically required for single-wall above-ground pipes. For example, there are one-piece collar-type supports which by design fit less than perfectly around the external circumference of the inner pipe, in order to slip the support into position over the inner pipe. This type of collar support is then secured in place typically by welding or otherwise bonding the support to the inner pipe. Thus, although such a support may surround the inner pipe, it typically does not maintain sufficient support of the entire circumference of the inner pipe because its inner diameter is inherently greater than the outer diameter of the inner pipe. This is a particular disadvantage with fiberglass pipes, which typically require uniform support along the entire circumference of the inner pipe.
SUMMARY OF THE INVENTION
The present invention is directed to a centering support for a double-containment pipe assembly including an inner pipe within an outer pipe. The centering support comprises a first half defining a first surface substantially conforming to the curvature of the outer surface of the inner pipe, and a second half defining a second surface substantially conforming to the curvature of the outer surface of the inner pipe. The first and second surfaces are seated on opposite sides of the inner pipe relative to each other on the outside surface of the inner pipe, and the first and second halves are coupled together by at least one fastening member for coupling the centering support to the inner pipe.
In one embodiment of the present invention, the first and second surfaces are substantially defined by a first radius slightly greater than the radius of the outside surface of the inner pipe. The first half further defines a third surface substantially conforming to the curvature of the inside surface of the outer pipe, and the second half further defines a fourth surface substantially conforming to the curvature of the inside surface of the outer pipe.
In one embodiment of the present invention, at least one of the first and second halves includes at least one flange portion for receiving a fastening member for coupling the first and second halves together on the inner pipe. A substantially flat portion is preferably defined adjacent the flange portion to facilitate insertion of a tool to manipulate the fastening member coupled through the flange portion. In one embodiment of the present invention, at least one of the first and second halves includes two flange portions, each being located on a distal end of the respective half for receiving a fastening member for coupling the first and second halves together on the inner pipe.
Preferably, at least one of the third and fourth surfaces includes a void or cut-out for air flow or drainage through an annulus between the inner and outer pipes. A resilient material is also preferably inserted between the first and second surfaces and the inner pipe to facilitate firmly engaging the centering support to the inner pipe, without subjecting the inner pipe to any damaging stress.
In one embodiment of the present invention, the first and second halves are coupled together on one end by a hinge member and coupled together on the other end by the fastening member.
One advantage of the centering support of the present invention, is that because the first and second surfaces of the halves substantially conform to the outer surface of the inner pipe, and the two halves are mechanically coupled together by the fastening member, the centering support is firmly engaged with the inner pipe throughout the circumference of the inner pipe to support the inner pipe. The degree to which the centering support firmly engages the inner pipe is selected by simply adjusting the fastening member.
Another advantage of the centering support of the present invention, is that it does not have to be welded or otherwise bonded to either the inner or outer pipe, but rather is simply mechanically coupled to the inner pipe by the fastening member. This results in significant time savings, and thus cost savings in assembling a double-containment pipe assembly.
Other advantages of the centering support of the present invention will become apparent in view of the following detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is cross-sectional view of a centering support embodying the present invention taken along the line 1--1 of FIG. 2.
FIG. 2 is side view of the centering support of FIG. 1.
FIG. 3 is a cross-sectional view of another centering support embodying the present invention formed by coupling together two upper halves of the centering support of FIG. 1.
FIG. 4 is a cross-sectional view of another centering support embodying the present invention formed by coupling together essentially two lower halves of the centering support of FIG. 1.
FIG. 5 is a front plan view of another centering support embodying the present invention in which the two halves of the centering support are coupled together by a hinge assembly.
FIG. 6 is a side view of the centering support of FIG. 5.
DETAILED DESCRIPTION
In FIG. 1, a centering support embodying the present invention is indicated generally by the reference numeral 10. The centering support 10 includes an upper half 12 and a lower half 14. The upper half 12 defines an upper semi-circular surface 16, and the lower half 14 defines a lower semi-circular surface 18. The upper and lower halves 12 and 14 are fitted over a primary pipe A, illustrated in phantom lines in FIG. 2, and coupled together by fasteners 20. In the embodiment of the present invention illustrated, the fasteners 20 are bolts having either socket or allen heads, and threaded portions for attachment to the lower half 14. An elastomeric or other type of resilient material 24 is preferably fitted between the upper and lower semi-circular surfaces 16 and 18, respectively, to facilitate the ability to tightly couple the upper and lower halves onto the primary pipe A. The semi-circular surfaces 16 and 18 are each defined by a radius R1, which is preferably slightly greater than the outside radius of the primary pipe A to permit insertion of the elastomeric material 24 between the primary pipe A and centering support 10.
As shown in FIG. 1, the upper half 12 has a generally omega-shape, which is defined by flats 26 on either side of the upper half relative to each other, a curved top surface 32 extending between the flats 26, and corresponding flange portions 28, each oriented substantially perpendicular to a respective flat 26. Each flange portion 28 defines an aperture 30 for receiving a respective fastener 20. Each flat 26 is substantially parallel to the vertical centerline of the upper half 12 to facilitate insertion of a socket or allen wrench, or other type of tool adjacent the flat to tighten or remove the respective fastener 20.
The surface 32 is defined by a radius R2, which is slightly less than the inside radius of an outer or containment pipe B, illustrated in phantom lines in FIG. 2, to permit insertion of the assembled centering support 10 and primary pipe A within the outer pipe B. The edges of the top surface 32 are preferably beveled, as shown by phantom lines in FIG. 1, to facilitate insertion within the outer pipe B. A generally semi-circular cut-out 34 may be formed within the approximate central portion of the top surface 32 to permit continuous flow of air within the annulus between the primary pipe A and the outer pipe B. The cut-out 34 may take any of numerous shapes to permit the flow of air through the annulus. For example, the cut-out 34 may equally take the shape of a flat or chord, as indicated by phantom lines in FIG. 1. The transition points between the various surfaces are preferably defined by either a smooth radius or fillet, as shown in FIG. 1, to prevent localized stress under load, such as when the fasteners 20 are tightened.
The lower half 14 is generally saddle-shaped, as shown in FIG. 1, and includes a lower surface 36 also defined by the radius R2. The edges of the lower surface 36 are also preferably beveled, as indicated by phantom lines in FIG. 1, to facilitate insertion of the assembled centering support 10 and primary pipe A within the outer pipe B. A flat surface (or chord) 38 may be formed in the approximate central portion of the lower surface 36 to permit the drainage of fluid, if any, through the annulus between the inner and outer pipes. The surface 38 may take any of numerous shapes to permit the flow of fluid through the annulus. For example, the surface 38 may take the shape of a semi-circle as indicated in phantom lines in FIG. 1. The distal ends of the lower half 14 are each defined by a flat surface 40 for seating against a respective flange portion 28 of the upper half 12. A threaded aperture 42 is formed within each flat surface 40 for receiving the threaded portion of a respective fastener 20 to clamp the upper and lower halves together around the primary pipe A. As with the upper half 12, the transition points between the various surfaces of the lower half 14 are each preferably defined by a smooth radius to prevent localized stress under load.
The upper and lower halves 12 and 14 may be constructed of any suitable material, including metal, reinforced-thermosetting plastic, or thermoplastic. The upper and lower halves 12 and 14 may also include recesses 44 formed in the side surfaces, as indicated by phantom lines in FIG. 2. The recesses 44 are particularly suitable when the halves 12 and 14 are formed by injection molding, resin-transfer molding, compression molding, or casting, for example. The recesses 44 not only result in the use of less material for the halves 12 and 14, but can also increase the overall strength of the centering support 10 by forming a ribbed configuration. The recesses 44 are dimensioned in a manner known to those of ordinary skill in the art so as to leave sufficient wall thickness adjacent the threaded apertures 42 to avoid failure.
In FIG. 3, another embodiment of the present invention is illustrated in which the centering support 10 is formed by two upper halves 12 which can be coupled together on an inner pipe A. The two upper halves 12 are each the same as the upper half 12 described above in connection with FIGS. 1 and 2, and therefore like reference numerals are used to indicate like elements. In this embodiment of the present invention, the adjacent flange portions 20 are coupled together by bolts extending through the aligned apertures 30 and secured in place by respective nuts. One advantage of this embodiment of the present invention is that it is only necessary to manufacture the upper half 12, thus reducing the overall cost of the double-containment piping system.
In FIG. 4 another embodiment of the present invention is illustrated, in which two lower halves 14 are coupled together to form the centering support 10. In this embodiment of the present invention each lower half 14 is essentially the same as the lower half described above in connection with FIG. 1, and therefore like reference numerals are used to indicate like elements. The two halves 14 differ only in that the top half has counter-sunk holes 45 defined in the surface 36 to receive the fasteners 20, and a cut-out 34 rather than a flat 38. The other half 14 has corresponding threaded holes 42, as described above, for receiving the threaded portions of the fasteners to couple the two halves together onto the inner pipe. This centering support is similarly advantageous in that because the two halves are very similar in construction, the overall complexity, and thus cost of the centering support is reduced.
In FIGS. 5 and 6 another embodiment of the present invention is illustrated which is similar to the embodiment of FIG. 4, and therefore like reference numerals are used to indicate like elements. The embodiment of FIGS. 5 and 6 differs from the embodiment of FIG. 4 essentially in that the two halves 14 are coupled together on one end by a hinge assembly 46, and coupled together on the other end by a fastener 20. The hinge assembly 46 is formed by a pair of lobes 48, each being formed on one end of each half 14, and which are coupled together by a hinge fastener 50. Thus, the centering support can be opened by moving the two halves relative to each other about the hinge assembly 46 to fit the support over the inner pipe. The centering support can then be firmly coupled to the inner pipe by tightening the fastener 20. As will be recognized by those skilled in the art, numerous different hinge configurations may be employed. One advantage of this embodiment of the present invention, is that the time required for assembly of the centering support to the primary pipe is reduced because only one fastener is required to attach the centering support to the primary pipe.
One advantage of the centering support of the present invention is that it can be used to electrically isolate the primary pipe A from the outer pipe B, or from other components of the double-containment piping system. For example, if the primary pipe A and outer pipe B are metal, the centering support 10 can be made from a non-metallic material, such as a thermosetting plastic, and thus can effectively electrically isolate the primary pipe from the outer pipe. With prior centering support devices which require welding or otherwise bonding of the centering support to the inner pipe, this advantage cannot be achieved. In the system of the present invention, because the two halves are simply mechanically coupled together on the inner pipe, electrical isolation can be easily and inexpensively achieved between the inner and outer pipes.
Another advantage of the centering support of the present invention is that because the inside surfaces (16 and/or 18) substantially conform to the outer diameter of the inner pipe, and the two halves are mechanically coupled together, the centering support is firmly engaged with the inner pipe throughout the circumference of the inner pipe to support the inner pipe. The degree to which the centering support engages the inner pipe is selected by simply adjusting the fastener(s) 20. With prior one-piece collar-type supports, for example, this result typically cannot be achieved because the inner diameter of the collar support is inherently greater than the outer diameter of the inner pipe.
Another advantage of the centering support of the present invention is that the support does not have to be welded or otherwise bonded to either the inner or outer pipe as with prior centering supports for double-containment piping systems. Rather, the centering support of the present invention is simply mechanically coupled to the primary pipe by tightening the fasteners, which in turn drives the two halves together into firm engagement with the entire circumference of the inner pipe. Accordingly, it is significantly easier and faster to assemble a double-containment piping system with the centering supports of the present invention in comparison to systems using one-piece collar supports, or supports similarly requiring welding or bonding for assembly.
It is noted that numerous variations can be made to the centering support 10 that are within the scope of the present invention. For example, the particular shape and location of the cut-outs to permit the flow of air or the drainage of fluid through the annulus between the inner and outer pipes may be varied, along with the location of the cut-outs. For example, it may be desirable to form apertures through one or both halves to perform this same function.
It is also noted that numerous types of fastening means may be employed to couple the upper and lower halves together. Hex-head, socket-head, or allen-head fasteners are only examples of the numerous types of fasteners that may equally be employed. The particular surface configuration of the flats 26 may also be varied as long as they are shaped to permit insertion of a socket wrench, or other type of tool, for tightening the fasteners 20. For example, the flats 26 may be formed with a curved surface configuration.
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A centering support for a double containment pipe assembly of an inner pipe located within an outer pipe, has a first half defining a first surface substantially conforming to the outer surface of the inner pipe, and a second half defining a second surface substantially conforming to the outer surface of the inner pipe. The first and second surfaces are seated on the outside surface of the inner pipe, and the first and second halves are coupled together by at least one fastening member for coupling the centering support to the inner pipe.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application relates to and claims the benefit of priority to U.S. Provisional Patent Application No. 60/719,375 filed on Sep. 22, 2005, incorporated herein by reference in its entirety.
BACKGROUND
[0002] The present disclosure relates to airflow control devices for vehicles, and more particularly, to reversibly deployable vehicle spoilers that use active materials to effect deployment and retraction.
[0003] Airflow over, under, around, and/or through a vehicle can affect many aspects of vehicle performance including vehicle drag, vehicle lift and down force, and cooling/heat exchange for a vehicle powertrain and air conditioning systems. Reductions in vehicle drag improve fuel economy. Vehicle lift and downforce can affect vehicle stability and handling. As used herein, the term “airflow” refers to the motion of air around and through parts of a vehicle relative to either the exterior surface of the vehicle or surfaces of elements of the vehicle along which exterior airflow can be directed such as surfaces in the engine compartment. The term “drag” refers to the resistance caused by friction in a direction opposite that of the motion of the center of gravity for a moving body in a fluid. The term “lift” as used herein refers to the component of the total force due to airflow relative to a vehicle acting on the vehicle in a vertically upwards direction. The term “downforce” used herein refers to the component of total force due to airflow relative to the vehicle acting on a vehicle in a vertically downward direction.
[0004] Devices known in the art of vehicle manufacture to control airflow relative to a vehicle are generally of a predetermined, non-adjustable geometry, location, orientation and stiffness. Such devices generally do not adapt as driving conditions change, thus the airflow relative to the vehicle cannot be adjusted to better suit the changing driving conditions. Additionally, current under-vehicle airflow control devices can reduce ground clearance. Vehicle designers are faced with the challenge of controlling the airflow while maintaining sufficient ground clearance to avoid contact with and damage by parking ramps, parking blocks, potholes, curbs and the like. Further, inclement weather, such as deep snow slush or rainfall, can damage the device and/or impair vehicle handing.
[0005] There are many general types of airflow control devices used for vehicles. One of these is spoilers. FIG. 1 illustrates a vehicle 1 that includes a spoiler 5 in the location typically associated with its function as discussed below. A spoiler is designed to improve traction by increasing the downward force on the rear portion of a vehicle. The use of spoilers increases the cornering capability and improves stability at high speeds, but often at the expense of additional aerodynamic drag and weight. Without the presence of a spoiler, the area at the rear of the vehicle would experience more lift at higher speeds as a function of the flow aerodynamics.
[0006] Current spoilers are generally of a fixed geometry, location, orientation, and stiffness. Such devices can thus not be relocated, reoriented, reshaped, etc. as driving conditions change and thus airflow over/around the vehicle body can not be adjusted to better suit the changed driving condition. In those spoilers that are not of a fixed geometry, location, etc., the spoilers are typically made adjustable by mounting and/or connecting the devices to hydraulic, mechanical, electrical actuators and/or the like. For example, some vehicle spoilers may adjust location and/or orientation in response to an actuator signal. However, such actuators generally require additional components such as pistons, motors, solenoids and/or like mechanisms for activation, which increase the complexity of the device often resulting in increased failure modes, maintenance, and manufacturing costs.
[0007] Accordingly, it would be desirable to have a deployable spoiler that can be tuned according to the driving conditions and that enhances device simplicity while reducing device problems and the number of failure modes.
BRIEF SUMMARY
[0008] Reversibly deployable spoilers and methods are disclosed herein. In one embodiment, the spoiler defines a surface of the vehicle that can increase or decrease airflow down force during movement of the vehicle. The spoiler comprises a housing having an opening; an airflow control member translatably disposed within the housing and slidably engaged with the opening; and an active material actuator comprising an active material in operative communication with the airflow control member to effect deployment and retraction of the airflow control member from and into the housing.
[0009] In another embodiment, the spoiler comprises a housing comprising an airflow control member rotatably disposed within the housing, wherein rotation of the airflow control member increases or decreases airflow down force during movement of the vehicle; and an active material actuator in operative communication with the airflow control member to effect rotation of the airflow control member.
[0010] In yet another embodiment, a spoiler for a vehicle comprises a post translatable to a vehicle surface; an airflow control member mounted on the post; and an active material actuator comprising an active material in operative communication with the post to effect translation of the post relative to the vehicle surface.
[0011] In still another embodiment, the spoiler comprises a flexible surface positioned on the vehicle so as to affect airflow down force upon flexure thereof; a rotatable cam in contact with the flexible surface; and an active material actuator in operative communication with the airflow control member to effect rotation of the cam and cause flexure to the flexible surface.
[0012] The above described and other features are exemplified by the following figures and detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Referring now to the figures, which are exemplary embodiments and wherein like elements are numbered alike:
[0014] FIG. 1 illustrates a vehicle that includes a spoiler in a location typically associated with its function;
[0015] FIG. 2 illustrates a sectional view of a reversibly deployable spoiler for a vehicle in a retracted position in accordance with one embodiment of the present disclosure;
[0016] FIG. 3 illustrates a sectional view of the reversibly deployable spoiler of FIG. 2 in a deployed position;
[0017] FIG. 4 illustrates a sectional view of a reversibly deployable spoiler for a vehicle in a deployed position in accordance with another embodiment of the present disclosure;
[0018] FIG. 5 illustrates a sectional view of the reversibly deployable spoiler of FIG. 4 in a retracted position;
[0019] FIG. 6 illustrates a sectional view of a reversibly deployable spoiler for a vehicle in a retracted position in accordance with yet another embodiment of the present disclosure;
[0020] FIG. 7 illustrates a sectional view of the reversibly deployable spoiler of FIG. 6 in a deployed position;
[0021] FIG. 8 illustrates a sectional view of a reversibly deployable spoiler that employs a rotary mechanism in accordance with another embodiment;
[0022] FIG. 9 illustrates a sectional view of a reversibly deployable spoiler that employs a rotary mechanism in accordance with yet another embodiment;
[0023] FIG. 10 illustrates a perspective view of a reversibly deployable spoiler that utilizes active material translatable posts in accordance with another embodiment;
[0024] FIG. 11 is a sectional view of the reversibly deployable spoiler of FIG. 10 ;
[0025] FIG. 12 illustrates a suitable active material actuator for retracting the spoiler of FIG. 10 ; and
[0026] FIG. 13 illustrates a suitable active material actuator for deploying the spoiler of FIG. 10 .
DETAILED DESCRIPTION
[0027] Active material actuated reversibly deployable airflow spoilers are disclosed herein. The airflow spoilers are suitable for use on vehicles on which it might be desirable to have on-demand greater downforce such as may be desired for vehicles utilized on occasion in competitive driving. It should be apparent that the airflow spoilers are mounted on a surface of the vehicle that can affect downforce to the vehicle during driving conditions. Typically, this position is at or about a rear deck of the vehicle although it is not intended to be limited to such location. Either deployment or stowing of the spoiler in these embodiments is in each case based on either a rigid body translation or rotation effected through just a single activation cycle (or at most a very small number of activation cycles) of an active material. Advantages associated with utilizing active materials to effect these changes include, among others, increased device simplicity, a reduced number of failure modes and thus increased device robustness, and reduced device volumes, masses, and energy requirements for activation because of their higher energy densities.
[0028] The classes of active materials included are those that exhibit a change in stiffness and/or dimensions in response to an actuation signal which can take various forms depending on the particular active material. Suitable active materials include, but are not limited to, shape memory alloys (SMA), shape memory polymers (SMP), electroactive polymers (EAP), ferromagnetic SMAs, electrorheological fluids (ER), magnetorheological fluids (MR), piezoelectric ceramics, various combinations of the foregoing materials, and the like such as is disclosed in pending U.S. patent application Ser. Nos. 10/983,330, 10/893,119, 10/872,327, and 10/983,329, all of which are incorporated by reference in their entireties.
[0029] The active material based spoiler devices for controlling vehicle airflow are generally directed to devices in which the active material (one or more) is connected externally either directly or remotely to a surface of an airflow control member causing either rigid body translation, rotation, or morphing of the airflow control device's airflow control surfaces.
[0030] In an embodiment shown in FIGS. 2 and 3 , there is shown a spoiler generally designated by reference numeral 10 in the retracted and deployed positions, respectively. The spoiler 10 includes a housing 12 that contains an active material based actuator 14 and a deployable airflow member 16 . The housing 12 has a bottom wall 18 , sidewalls 20 extending from the bottom wall and a top wall 22 . The housing 12 includes a slot opening 24 in the top wall 22 and is configured to permit retraction and deployment of the airflow control member 16 into and out of the housing 12 . The active material 26 is in operative communication with the deployable airflow member to provide the retraction and deployment.
[0031] Using shape memory alloys as an exemplary active material, a shape memory alloy wire 26 is tethered at one end to a selected one of the walls or stationary anchor structure 38 within the housing 12 and at the other end is tethered to the second portion 30 of the airflow control member 16 . As shown, the deployable airflow member 16 is generally “L” shaped having a first portion 28 slidably engaged with the slot opening 24 and a second portion 30 substantially perpendicular to the first portion. The housing 12 further includes a bias spring retaining structure 32 that is attached or integral to the top wall 22 to which the airflow control member 16 is slidably mounted. A bias spring 34 is disposed intermediate and in a biased relationship with the second portion of the airflow control member 16 and the bias spring retaining structure 32 . The bias spring retaining structure 32 further includes a channel 36 for receiving the shape memory alloy wire 26 , which has one end fixedly attached to an anchor structure 38 within the housing and the other end and fixedly attached to the second portion 30 . The shape memory alloy wire 26 is disposed about one or more pulleys 42 and threaded through the channel 36 to provide vertical movement of the airflow control member 16 . Activation of the shape memory alloy wire 26 causes a phase transformation, which results in contraction of the wire with a force sufficient to overcome those forces associated with the bias spring 34 . The result is that the airflow control member 16 is slidably deployed from the slot opening 24 . Deactivation causes the bias spring to psuedoplastically deform the shape memory alloy back to about its original position and length, which also results in retracting the airflow control member 16 . In this manner, airflow as indicated by arrows 46 can be altered, which can be used to affect the downforce caused by the airflow on the vehicle. An optional flap seal 44 is disposed about the slot opening 24 to prevent particulate matter from entering the housing.
[0032] For this and other embodiments disclosed herein, the bias spring is generally chosen so that its axial stiffness (i.e., spring constant) is greater than that of the active material when the active material is not activated. For example, in the case of the shape memory alloy wire, the axial stiffness of the bias spring is chosen to be greater than that of the shape memory alloy wire when it is in its lower temperature martensite stiffness and is less than that of the wire when it is in its higher temperature austenite phase.
[0033] In FIGS. 4 and 5 , a spoiler 50 is shown in the deployed and retracted positions, respectively. The spoiler 50 includes a housing 52 having a bottom wall 54 , a top wall 56 , and sidewalls 58 . The housing 52 further includes a slot opening 60 in which an airflow control member 62 is slidably engaged therewith. The airflow control member 62 is generally “L” shaped having a first portion 64 and a second portion 66 substantially perpendicular to the first portion. A bias spring 68 has one end fixed attached to the second portion 66 and the other end fixedly attached to the bottom wall 54 . An active material 70 , e.g., is tethered at one end to a selected one of the walls or stationary anchor structure 72 within the housing 62 and at the other end is tethered to the second portion 66 of the airflow control member 62 . The shape memory alloy wire 70 is disposed about one or more pulleys 74 and configured to provide vertical movement of the airflow control member 62 . Activation of the shape memory alloy wire 70 causes a phase transformation, which results in contraction of the wire with a force sufficient to overcome those forces associated with the bias spring 68 .
[0034] In this embodiment, activation of the shape memory alloy wire 70 would cause simultaneous contraction of the shape memory alloy wire and expansion of the bias spring to deploy the airflow control member 62 as opposed to compressive process shown in previous embodiment discussed immediately above. Deactivation of the shape memory alloy wire would result in the bias spring pseudoplastically deforming the shape memory alloy wire to retract the airflow control member within the housing 62 . A seal can be disposed about the slot opening.
[0035] In FIGS. 6 and 7 , a spoiler 80 is shown in the retracted and deployed positions, respectively. The spoiler 80 includes a housing 82 having a bottom wall 84 , a top wall 86 , and sidewalls 88 . The housing 52 further includes a slot opening 90 in which an airflow control member 92 is slidably engaged therewith. The slot opening 90 extends to the bottom wall and includes a shoulder 94 distally located from the top surface 86 . The airflow control member 92 has a generally planar shape and is slidably engaged with the slot opening.
[0036] An active material 96 , e.g., shape memory alloy wire, is tethered at one end to the airflow control member 92 and at the other end to the bottom wall 84 within the housing 82 . The shape memory alloy wire 96 is configured to provide vertical movement of the airflow control member 82 . A bias spring 98 is seated onto the shoulder 94 and is in contact with the airflow control member 92 . The bias spring 98 is dimensioned such that in the absence of an activation signal to the shape memory alloy wire, the bias spring positions the airflow control member 82 into the air flow path, i.e., causes deployment of the airflow control member from the housing. Upon activation of the shape memory alloy wire, the wire contracts causing the bias spring to compress, thereby retracting the airflow control member 82 . As such, the length of the slot opening to the shoulder of the recess is about equal or less than the length of the airflow deployable member 92 and the length of the bias spring upon compression by the shape memory alloy wire.
[0037] In another embodiment shown in FIG. 8 , a spoiler 100 is depicted in which the active material (one or more) is connected externally either directly or remotely to the airflow control member 102 . In this example, the airflow control surface 102 is attached to a axle 104 , which is free to rotate about its axis. A spring 106 and an SMA wire 108 are attached to the hollow tube 104 in an opposing fashion such that their tensions balance each other and rotation of the tube through external means will increase the tension in one while reducing tension in the other. At low vehicle speeds, tension in the spring 106 combined with reduced stiffness and greater length in the SMA wire 108 keeps the spoiler rotated flush to the vehicle surface and out of the way. At high vehicle speeds, the temperature of the SMA wire is raised, e.g., through resistance heating, to produce a phase change from martensite to austenite in the SMA wire. This results in typically a four percent reduction in its length and a significant increase in its stiffness. This combined change in length and stiffness results in a rotation—deployment—of the airflow control device and a stretching of the counterbalancing spring 106 . Upon shutting off the current that is causing resistance heating of the SMA wire, the wire cools to its martensite phase and the stretched spring returns the airflow control device to its stowed position.
[0038] Although reference has been made specifically to the use of shape memory alloys, it is to be noted that an EAP could also be used in place of SMA as the actuator in these embodiments in order to achieve the desired linear or rotary deployment. Especially in the case of deployment by translation, packaging becomes much less an issue with EAP, as variously in tendon, sheet, or slab form, EAP can be made to experience 100% strain when subjected to an applied voltage.
[0039] Embodiments are also envisioned, as indicated, in which the externally attached active material is used to morph the airflow control surface(s) of the spoiler. As shown in FIG. 9 , the spoiler 110 includes a cam-like device that is located adjacent to a flexible surface of an airflow control member 114 . Activation of an active material 116 physically linked to the cam 112 , such as an SMA wire or spring or an EAP sheet or tendon will cause rotation of the cam, which rotation elastically deforms the flexible airflow control surface of the airflow control device. A bias spring 118 , which could take various forms, or the energy stored elastically in the deformed surface could be used to return the surface of the airflow control device to its original configuration once the activation signal is removed.
[0040] In an alternative embodiment, the airflow control devices can be configured with latching mechanisms, involving either active materials directly (such as holding in position through the field activated change in shear strength in ER and MR fluids), or that are active material actuated or otherwise, that hold the deployable airflow control device in either the deployed or stowed positions thus allowing either power on or power off position/shape hold, i.e., in power off approaches power for actuation is then only needed in these embodiments during deploying or stowing of the active airflow control device.
[0041] In another embodiment, the spoiler defines a discrete body (i.e., airflow member) positioned on, positioned above, or positioned within a recess within the vehicle surface, that by its movement/repositioning with respect to the vehicle surface can increase or decrease airflow down force during movement of the vehicle. As shown in FIGS. 10 and 11 , the spoiler 120 is illustrated utilizing active material translatable posts 122 upon which the air deflecting member 124 is seated.
[0042] The spoiler 120 includes a spoiler body 122 (i.e., airflow control member) seated onto at least one post 124 (two of which are shown in FIG. 10 ). The post is translatable with respect the vehicle body 126 . By way of example, the post is disposed within a recess 128 formed in the vehicle body. However, it should be noted that the posts may be variously slidably engaged with slot opening in the airflow control member, the vehicle surface, or both and/or contain telescoping portions that can extend or shorten their height. An active material actuator similar to those discussed above comprising an active material is disposed in operative communication with the airflow control member to effect raising, lowering, and/or rotating of the airflow control member with respect to the vehicle surface. A latch 130 may be employed to lock the airflow member 122 at a desired position, e.g., in the fully deployed or retracted positions, which then permits deactivation of the active material while maintaining the position of the airflow control member.
[0043] FIG. 12 illustrates an exemplary active material actuator 140 that retracts the post 124 when the active material is activated. The post 124 is seated on a compression spring 142 . An active material such as a shape memory alloy wire is anchored to the spoiler at one end 146 and to the vehicle 126 at another end 148 . One or more pulleys 150 can be utilized to configure the active material actuator 140 . The post 124 moves downward and is latched upon activation of the active material 144 as shown. Upon deactivation, the latch can be selectively unlatched causing the compression spring to decompress and deploy the post and airflow member 122 from the vehicle body. In the case of shape memory alloys, the wire would pseudoplastically deform.
[0044] FIG. 13 illustrates an exemplary active material actuator 160 that deploys the post when the active material is activated. In this embodiment, a compression spring 162 is biased such that the post 124 is in the retracted position when the active material (counterforce) is not activated. Upon activation of the active material 166 , the post deploys from the vehicle body. Using shape memory alloys as an exemplary active material, one end of the SMA is anchored to the vehicle at anchor point 168 and at its other end to the post 124 at anchor point 170 . Optionally, a pulley 164 can be employed. A latch 130 can be used to selectively maintain the spoiler in an “up” position even when the active material is deactivated. The latch can be integrated with the active material actuator (i.e., be active material actuated), mechanically actuated, hydraulically actuated, or pneumatically actuated as may be desired for different applications. In a preferred embodiment, the actuator wires are horizontally disposed within the length of the spoiler or within the vehicle body.
[0045] Active material includes those compositions that can exhibit a change in stiffness properties, shape and/or dimensions in response to the activation signal, which can take the type for different active materials, of electrical, magnetic, thermal and like fields. Preferred active materials include but are not limited to the class of shape memory materials, and combinations thereof. Shape memory materials generally refer to materials or compositions that have the ability to remember their original at least one attribute such as shape, which can subsequently be recalled by applying an external stimulus, as will be discussed in detail herein. As such, deformation from the original shape is a temporary condition. In this manner, shape memory materials can change to the trained shape in response to an activation signal.
[0046] Generally, SMPs are phase segregated co-polymers comprising at least two different units, which may be described as defining different segments within the SMP, each segment contributing differently to the overall properties of the SMP. As used herein, the term “segment” refers to a block, graft, or sequence of the same or similar monomer or oligomer units, which are copolymerized to form the SMP. Each segment may be crystalline or amorphous and will have a corresponding melting point or glass transition temperature (Tg), respectively. The term “thermal transition temperature” is used herein for convenience to generically refer to either a Tg or a melting point depending on whether the segment is an amorphous segment or a crystalline segment. For SMPs comprising (n) segments, the SMP is said to have a hard segment and (n- 1 ) soft segments, wherein the hard segment has a higher thermal transition temperature than any soft segment. Thus, the SMP has (n) thermal transition temperatures. The thermal transition temperature of the hard segment is termed the “last transition temperature”, and the lowest thermal transition temperature of the so-called “softest” segment is termed the “first transition temperature”. It is important to note that if the SMP has multiple segments characterized by the same thermal transition temperature, which is also the last transition temperature, then the SMP is said to have multiple hard segments.
[0047] When the SMP is heated above the last transition temperature, the SMP material can be shaped. A permanent shape for the SMP can be set or memorized by subsequently cooling the SMP below that temperature. As used herein, the terms “original shape”, “previously defined shape”, and “permanent shape” are synonymous and intended to be used interchangeably. A temporary shape can be set by heating the material to a temperature higher than a thermal transition temperature of any soft segment yet below the last transition temperature, applying an external stress or load to deform the SMP, and then cooling below the particular thermal transition temperature of the soft segment.
[0048] The permanent shape can be recovered by heating the material, with the stress or load removed, above the particular thermal transition temperature of the soft segment yet below the last transition temperature. Thus, it should be clear that by combining multiple soft segments it is possible to demonstrate multiple temporary shapes and with multiple hard segments it may be possible to demonstrate multiple permanent shapes. Similarly using a layered or composite approach, a combination of multiple SMPs will demonstrate transitions between multiple temporary and permanent shapes.
[0049] For SMPs with only two segments, the temporary shape of the shape memory polymer is set at the first transition temperature, followed by cooling of the SMP, while under load, to lock in the temporary shape. The temporary shape is maintained as long as the SMP remains below the first transition temperature. The permanent shape is regained when the SMP is once again brought above the first transition temperature. Repeating the heating, shaping, and cooling steps can repeatedly reset the temporary shape.
[0050] Most SMPs exhibit a “one-way” effect, wherein the SMP exhibits one permanent shape. Upon heating the shape memory polymer above a soft segment thermal transition temperature without a stress or load, the permanent shape is achieved and the shape will not revert back to the temporary shape without the use of outside forces.
[0051] As an alternative, some shape memory polymer compositions can be prepared to exhibit a “two-way” effect, wherein the SMP exhibits two permanent shapes. These systems include at least two polymer components. For example, one component could be a first cross-linked polymer while the other component is a different cross-linked polymer. The components are combined by layer techniques, or are interpenetrating networks, wherein the two polymer components are cross-linked but not to each other. By changing the temperature, the shape memory polymer changes its shape in the direction of a first permanent shape or a second permanent shape. Each of the permanent shapes belongs to one component of the SMP. The temperature dependence of the overall shape is caused by the fact that the mechanical properties of one component (“component A”) are almost independent from the temperature in the temperature interval of interest. The mechanical properties of the other component (“component B”) are temperature dependent in the temperature interval of interest. In one embodiment, component B becomes stronger at low temperatures compared to component A, while component A is stronger at high temperatures and determines the actual shape. A two-way memory device can be prepared by setting the permanent shape of component A (“first permanent shape”), deforming the device into the permanent shape of component B (“second permanent shape”), and fixing the permanent shape of component B while applying a stress.
[0052] It should be recognized by one of ordinary skill in the art that it is possible to configure SMPs in many different forms and shapes. Engineering the composition and structure of the polymer itself can allow for the choice of a particular temperature for a desired application. For example, depending on the particular application, the last transition temperature may be about 0° C. to about 300° C. or above. A temperature for shape recovery (i.e., a soft segment thermal transition temperature) may be greater than or equal to about −30° C. Another temperature for shape recovery may be greater than or equal to about 20° C. Another temperature for shape recovery may be greater than or equal to about 70° C. Another temperature for shape recovery may be less than or equal to about 250° C. Yet another temperature for shape recovery may be less than or equal to about 200° C. Finally, another temperature for shape recovery may be less than or equal to about 180° C.
[0053] Suitable polymers for use in the SMPs include thermoplastics, thermosets, interpenetrating networks, semi-interpenetrating networks, or mixed networks of polymers. The polymers can be a single polymer or a blend of polymers. The polymers can be linear or branched thermoplastic elastomers with side chains or dendritic structural elements. Suitable polymer components to form a shape memory polymer include, but are not limited to, polyphosphazenes, poly(vinyl alcohols), polyamides, polyester amides, poly(amino acid)s, polyanhydrides, polycarbonates, polyacrylates, polyalkylenes, polyacrylamides, polyalkylene glycols, polyalkylene oxides, polyalkylene terephthalates, polyortho esters, polyvinyl ethers, polyvinyl esters, polyvinyl halides, polyesters, polylactides, polyglycolides, polysiloxanes, polyurethanes, polyethers, polyether amides, polyether esters, polystyrene, polypropylene, polyvinyl phenol, polyvinylpyrrolidone, chlorinated polybutylene, poly(octadecyl vinyl ether) ethylene vinyl acetate, polyethylene, poly(ethylene oxide)-poly(ethylene terephthalate), polyethylene/nylon (graft copolymer), polycaprolactones-polyamide (block copolymer), poly(caprolactone) dimethacrylate-n-butyl acrylate, poly(norbornyl-polyhedral oligomeric silsesquioxane), polyvinyl chloride, urethane/butadiene copolymers, polyurethane block copolymers, styrene-butadiene-styrene block copolymers, and the like, and combinations comprising at least one of the foregoing polymer components. Examples of suitable polyacrylates include poly(methyl methacrylate), poly(ethyl methacrylate), poly(butyl methacrylate), poly(isobutyl methacrylate), poly(hexyl methacrylate), poly(isodecyl methacrylate), poly(lauryl methacrylate), poly(phenyl methacrylate), poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutyl acrylate) and poly(octadecyl acrylate). The polymer(s) used to form the various segments in the SMPs described above are either commercially available or can be synthesized using routine chemistry. Those of skill in the art can readily prepare the polymers using known chemistry and processing techniques without undue experimentation.
[0054] Similar to shape memory polymers, shape memory alloys exist in several different temperature-dependent phases. The most commonly utilized of these phases are the so-called martensite and austenite phases. 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 (As). The temperature at which this phenomenon is complete is called the austenite finish temperature (Af). 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 (Ms). The temperature at which austenite finishes transforming to martensite is called the martensite finish temperature (Mf). Generally, the shape memory alloys are softer and more easily deformable in their martensitic phase and are harder, stiffer, and/or more rigid in the austenitic phase. In view of the foregoing properties, expansion of the shape memory alloy is preferably at or below the austenite transition temperature (at or below As). Subsequent heating above the austenite transition temperature causes the expanded shape memory alloy to revert back to its permanent shape. 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.
[0055] 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 shape memory effects, superelastic effects, and high damping capacity.
[0056] Suitable shape memory alloy materials include, but are not intended to be limited to, 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-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, changes in yield strength, and/or flexural modulus properties, damping capacity, superelasticity, and the like. Selection of a suitable shape memory alloy composition depends on the temperature range where the component will operate.
[0057] Active materials also include, but are not limited to, shape memory material such as magnetic materials and magnetorheological elastomers. Suitable magnetic materials include, but are not intended to be limited to, soft or hard magnets; hematite; magnetite; magnetic material based on iron, nickel, and cobalt, alloys of the foregoing, or combinations comprising at least one of the foregoing, and the like. Alloys of iron, nickel and/or cobalt, can comprise aluminum, silicon, cobalt, nickel, vanadium, molybdenum, chromium, tungsten, manganese and/or copper. Suitable MR elastomer materials have previously been described.
[0058] The spoilers and methods of the present disclosure are able to adjust features such as shape, dimension, stiffness, location, combinations thereof, and the like by changing the at least one attribute of active material to match the needs of different driving conditions. Changes in at least one attribute of active material include shape, dimension, stiffness, combinations thereof and the like. Utilizing active materials to affect these changes provide devices of increased simplicity and robustness, while reducing the number of failure modes, device volume and energy requirements for activation due to higher energy densities.
[0059] The active material may also comprise an electroactive polymer such as ionic polymer metal composites, conductive polymers, piezoelectric material and the like. As used herein, the term “piezoelectric” is used to describe a material that mechanically deforms when a voltage potential is applied, or conversely, generates an electrical charge when mechanically deformed.
[0060] Suitable MR elastomer materials include, but are not intended to be limited to, an elastic polymer matrix comprising a suspension of ferromagnetic or paramagnetic particles, wherein the particles are described above. Suitable polymer matrices include, but are not limited to, poly-alpha-olefins, natural rubber, silicone, polybutadiene, polyethylene, polyisoprene, and the like.
[0061] Electroactive polymers include those polymeric materials that exhibit piezoelectric, pyroelectric, or electrostrictive properties in response to electrical or mechanical fields. The materials generally employ the use of compliant electrodes that enable polymer films to expand or contract in the in-plane directions in response to applied electric fields or mechanical stresses. 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.
[0062] 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.
[0063] 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 or small 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. In many cases, electroactive polymers may be fabricated and implemented as thin films. Thicknesses suitable for these thin films may be below 50 micrometers.
[0064] 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.
[0065] Materials used for electrodes of the present disclosure may vary. Suitable materials used in an electrode may include graphite, carbon black, colloidal suspensions, thin metals including silver and gold, silver filled and carbon filled gels and polymers, and ionically or electronically conductive polymers. It is understood that certain electrode materials may work well with particular polymers and may not work as well for others. By way of example, carbon fibrils work well with acrylic elastomer polymers while not as well with silicone polymers.
[0066] The active material may also comprise a piezoelectric material. Also, in certain embodiments, the piezoelectric material may be configured as an actuator for providing rapid deployment. As used herein, the term “piezoelectric” is used to describe a material that mechanically deforms (changes shape) when a voltage potential is applied, or conversely, generates an electrical charge when mechanically deformed. Preferably, a piezoelectric material is disposed on strips of a flexible metal or ceramic sheet. The strips can be unimorph or bimorph. Preferably, the strips are bimorph, because bimorphs generally exhibit more displacement than unimorphs.
[0067] One type of unimorph is a structure composed of a single piezoelectric element externally bonded to a flexible metal foil or strip, which is stimulated by the piezoelectric element when activated with a changing voltage and results in an axial buckling or deflection as it opposes the movement of the piezoelectric element. The actuator movement for a unimorph can be by contraction or expansion. Unimorphs can exhibit a strain of as high as about 10%, but generally can only sustain low loads relative to the overall dimensions of the unimorph structure.
[0068] In contrast to the unimorph piezoelectric device, a bimorph device includes an intermediate flexible metal foil sandwiched between two piezoelectric elements. Bimorphs exhibit more displacement than unimorphs because under the applied voltage one ceramic element will contract while the other expands. Bimorphs can exhibit strains up to about 20%, but similar to unimorphs, generally cannot sustain high loads relative to the overall dimensions of the unimorph structure.
[0069] Suitable piezoelectric materials include inorganic compounds, organic compounds, and metals. With regard to organic materials, all of the polymeric materials with non-centrosymmetric structure and large dipole moment group(s) on the main chain or on the side-chain, or on both chains within the molecules, can be used as candidates for the piezoelectric film. Examples of suitable polymers include, for example, but are not limited to, poly(sodium 4-styrenesulfonate) (“PSS”), poly S-119 (poly(vinylamine)backbone azo chromophore), and their derivatives; polyfluorocarbons, including polyvinylidene fluoride (“PVDF”), its co-polymer vinylidene fluoride (“VDF”), trifluoroethylene (TrFE), and their derivatives; polychlorocarbons, including poly(vinyl chloride) (“PVC”), polyvinylidene chloride (“PVC2”), and their derivatives; polyacrylonitriles (“PAN”), and their derivatives; polycarboxylic acids, including poly(methacrylic acid (“PMA”), and their derivatives; polyureas, and their derivatives; polyurethanes (“PUE”), and their derivatives; bio-polymer molecules such as poly-L-lactic acids and their derivatives, and membrane proteins, as well as phosphate bio-molecules; polyanilines and their derivatives, and all of the derivatives of tetramines; polyimides, including Kapton molecules and polyetherimide (“PEI”), and their derivatives; all of the membrane polymers; poly(N-vinyl pyrrolidone) (“PVP”) homopolymer, and its derivatives, and random PVP-co-vinyl acetate (“PVAc”) copolymers; and all of the aromatic polymers with dipole moment groups in the main-chain or side-chains, or in both the main-chain and the side-chains, and mixtures thereof.
[0070] Further, piezoelectric materials can include Pt, Pd, Ni, Ti, Cr, Fe, Ag, Au, Cu, and metal alloys and mixtures thereof. These piezoelectric materials can also include, for example, metal oxide such as SiO 2 , Al 2 O 3 , ZrO 2 , TiO 2 , SrTiO 3 , PbTiO 3 , BaTiO 3 , FeO 3 , Fe 3 O 4 , ZnO, and mixtures thereof; and Group VIA and IIB compounds, such as CdSe, CdS, GaAs, AgCaSe 2 , ZnSe, GaP, InP, ZnS, and mixtures thereof.
[0071] Suitable active materials also comprise magnetorheological (MR) compositions, such as MR elastomers, which are known as “smart” materials whose rheological properties can rapidly change upon application of a magnetic field. MR elastomers are suspensions of micrometer-sized, magnetically polarizable particles in a thermoset elastic polymer or rubber. The stiffness of the elastomer structure is accomplished by changing the shear and compression/tension moduli by varying the strength of the applied magnetic field. The MR elastomers typically develop structure when exposed to a magnetic field in as little as a few milliseconds. Discontinuing the exposure of the MR elastomers to the magnetic field reverses the process and the elastomer returns to its lower modulus state.
[0072] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
[0073] While the disclosure has been described with reference to an exemplary embodiment, 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 disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims.
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A reversibly deployable spoiler for a vehicle comprises a body and an active material in operative communication with the body. The active material, such as shape memory material, is operative to change at least one attribute in response to an activation signal. The active material can change its shape, dimensions and/or stiffness producing a change in at least one feature of the active spoiler airflow control device such as shape, dimension, location, orientation, and/or stiffness to control vehicle airflow and downforce to better suit changes in driving conditions such as speed, while reducing maintenance and the level of failure modes. An activation device, controller and sensors may be employed to further control the change in at least one feature of the active spoiler airflow control device such as shape, dimension, location, orientation, and/or stiffness. A method for controlling vehicle airflow selectively introduces an activation signal to initiate a change of at least one feature of the device that can be reversed upon discontinuation of the activation signal.
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CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to headrests for seats. More particularly, the invention concerns a fully adjustable headrest for use in connection with furniture and with passenger vehicles such as aircraft, trains and busses.
2. Discussion of the Prior Art
Various types of headrests for use in passenger vehicles have been suggested in the past. As the general rule, these headrests are designed primarily to satisfy safety aspects rather than to provide a comfortable seating posture. Typically, the prior art vehicle headrests comprise only a vertically adjustable head support panel designed to provide protection against injury in the event of an accident. However, some vehicle headrests have also been provided with lateral headrest elements. Exemplary of such a headrest is that described in U.S. Pat. No. 5,997,091 issued to Rech et al.
Even more complex headrests have been designed for use in military aircraft and, more particularly in military aircraft for use in conjunction with ejection seats. Typical of this class of headrest design are those disclosed in U.S. Pat. No. 4,883,243 and U.S. Pat. No. 4,899,961 both issued to Herndon. Another such headrest design is disclosed in U.S. Pat. No. 4,466,662 issued to McDonald et al.
In addition to the development of headrests for use in military aircraft, significant advances have been made in recent years in the design of headrests for use in commercial aircraft. Exemplary of such headrests are those described in U.S. Pat. Nos. 6,250,716, 6,467,846, 6,666,517, 7,040,705, 7,264,313 and 7,364,239 issued to Clough.
As will become clear from the discussion that follows, the headrest of the present invention represents a substantial improvement over the prior art headrests and provides significantly greater ease of adjustability and therefore greater support and comfort to the user.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of one form of the seat headrest apparatus of the invention.
FIG. 2 is a rear view of the seat headrest apparatus shown in FIG. 1 .
FIG. 3 is a greatly enlarged, generally perspective, exploded view of the area designated in FIG. 1 as 3 - 3 .
FIG. 4 is a greatly enlarged, generally perspective, exploded view of the area designated in FIG. 3 as 4 - 4 showing the construction of one form of the friction detent hinge of the seat headrest apparatus.
FIG. 4A is a greatly enlarged view taken along lines 4 A- 4 A of FIG. 1 .
FIG. 4B is a view similar to FIG. 4A , but showing the friction detent hinge moved from a first, at rest position, to a second position.
FIG. 4C is a view similar to FIG. 4B , but showing the friction detent hinge moved from the second position to a third position.
FIG. 5 is a generally perspective, exploded rear view of the seat headrest shown in FIG. 1 .
FIG. 6 is a generally perspective, exploded rear view of the seat headrest shown in FIG. 5 illustrating the upward movement of the headrest relative to the elongated guide of the apparatus.
FIG. 7 is a generally perspective, exploded rear view of the seat headrest shown in FIG. 6 illustrating the manner of interconnection of the seat connector plate of the apparatus to the elongated guide.
FIG. 8 is a front view of an alternate form of seat headrest apparatus of the invention.
FIG. 9 is a rear view of the alternate form of seat headrest apparatus of the invention shown in FIG. 8 .
FIG. 10 is a generally perspective, exploded rear view of the alternate form of seat headrest shown in FIG. 9 .
FIG. 11 is a front view of the alternate form of seat headrest apparatus of the invention shown in FIG. 8 showing the headrest assembly pivoted forwardly relative to the elongated guide of the apparatus.
FIG. 12 is an enlarged view taken along lines 12 - 12 of FIG. 11 .
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an adjustable headrest that provides both support and comfort to the user and can be used in connection with furniture including household and office furniture and also in connection with various types of passenger vehicles.
Another object of the invention is to provide a headrest of the aforementioned character that includes slide means for permitting easy height adjustment of the headrest and also includes a friction imparting assembly for holding the headrest in a desired elevated position.
Another object of the invention is to provide easily adjustable, wing like, side support panels that are pivotally connected to a centrally located, vertically adjustable head support panel by means of novel friction hinges that include detent features that permit the wing like side support panels of the headrest to be locked into predetermined angular orientations.
Another object of the invention is to provide a seat connector that can be readily connected to a vehicle seat.
Another object of the invention is to provide a headrest construction of the class described that is of a simple construction and one that can be inexpensively produced and maintained.
DESCRIPTION OF THE INVENTION
Referring to the drawings and particularly to FIGS. 1 and 2 , one form of the seat headrest of the invention is there illustrated and generally designated by the numeral 14 . The seat headrest here comprises a support assembly 16 that includes a first, centrally disposed head support panel 18 , a second side panel 20 that is connected to panel 18 by a novel friction hinge assembly 22 and a third side panel 24 that is connected to central panel 18 by a novel friction hinge assembly 22 . To reduce the overall weight of the headrest, central head support panel 18 , as well as side panels 20 and 24 , are each provided with a multiplicity of weight reduction apertures 25 .
As will be discussed in greater detail hereinafter, side panels 20 and 24 are pivotally movable from an at rest position wherein they are substantially coplanar with the central head support panel 18 to selected angularly extending forward positions. When side panels 20 and 24 are pivoted into selected angularly forward positions, they can provide a comfortable lateral support to the passenger's head. As best seen in FIGS. 1, 2 and 5 of the drawings, support assembly 16 is connected to a mounting assemblage 26 that here comprises an elongated guide 28 and a connector plate 30 that can be connected to a seat “S” by any suitable means such as suitable connectors 33 (Figures land 5 ). Elongated guide 28 includes oppositely disposed guide rails 28 a that are adapted to be rollably engaged by two sets of transversely spaced apart roller assemblies 38 that are mounted on central head support panel 18 . The roller assemblies 38 , each of which are of identical construction, include grooved rollers 38 a that roll along guide rails 28 a so that the headrest assembly 16 can be adjustably moved upwardly and downwardly so as to enable the desired adjustment in the height of the assembly. A transversely extending connector member 40 spans the spaced apart rollers in the manner illustrated in FIG. 5 and defines a guide channel 41 within which guide 28 is disposed (see also FIG. 6 ). To reduce the overall weight of the assembly, connector plate 30 is provided with a multiplicity of weight reduction apertures 31 .
Forming an important aspect of the headrest assembly of this latest form of the invention is a resistance imparting assembly for imparting resistance to the movement of headrest assembly 16 upwardly and downwardly relative to guide 28 . In the present form of the invention, this novel resistance imparting assembly comprises a uniquely configured, generally T-shaped leaf spring designated in the drawings by the numeral 43 . As best seen in FIGS. 3 and 4 , spring 43 includes a transverse connector portion 43 a that is affixed to central head support panel 18 and a downwardly extending, curved central portion 43 b that extends into channel 41 . When the headrest assembly 16 is mounted on guide 28 in the manner shown in FIG. 5 , the curved central portion 43 b of the spring will be yieldably deformed so that it is brought into pressural engagement with the guide. With this construction, as the headrest assembly is moved upwardly and downwardly, the central portion 43 b of the spring will frictionally engage the surface of the guide 28 and will yieldably resist sliding movement of headrest assembly 16 relative to the guide.
Referring particularly to FIGS. 3 and 4 of the drawings, the friction hinge assemblies 22 of this embodiment of the invention can be seen to comprise an elongated, generally cylindrical shaped shaft 42 and first and second bands 44 and 46 that are rotatably carried by shaft 42 (see FIG. 3 ). Importantly, shaft 42 is provided with a pair of circumferentially spaced detents, or flats 42 a and 42 b ( FIGS. 4 and 4A ). As used herein, the term “detent” means a device for positioning and holding one part in relation to another in a manner such that the device can be released by force applied to one of the parts.
First and second bands 44 and 46 of each of the hinge assemblies 22 are connected to central panel 18 by suitable connectors “C”, while one of the shafts 42 of the hinge assemblies 22 is connected to the side panel 20 and the other of the shafts is connected to the side panel 24 . As best seen in FIG. 3 of the drawings, the shafts 42 are connected to the side panels by means of connector leaves 48 and suitable connectors 49 .
Importantly, band 44 of each of the hinge assemblies is provided with a detent engaging segment, or flat 50 that, as the band is rotated, is engageable with a selected one of the detents 42 a and 42 b of shaft 42 to prevent rotation of the band relative to the shaft. This novel detent feature of the friction hinges allows the user to feel the hinge snap into position when the hinge is rotated to a certain angle. More particularly, when the band is rotated around the shaft to the point where the detent engaging segment aligns with the detent on the shaft, the hinge snaps into place giving the user a positive indication that the hinge is in a selected position. The strength and feel of the detent feature is dependent on various factors including the depth of the flat on both the shaft and the band, the size of the shaft, the thickness of the band material, the hardness on both the shaft and the band, the type of grease used, the type of surface treatment done on the shaft and the band and the amount of interference between the shaft and the band. Hinge assemblies 22 are readily commercially available from Hanaya Inc. of Ponte Vedra, Fla.
As illustrated in FIG. 4A of the drawings, when the central panel 18 and the side panels are disposed in an at rest, coplanar configuration, the flat 50 on the band 44 resides in engagement with the cylindrical surface of the shaft 42 . It is to be noted that FIGS. 4A through 4C of the drawings show only part of central panel 18 and side panel 24 and illustrate only the angular adjustment of side panel 24 . However, it is to be understood that the angular adjustment of side panel 20 is accomplished in exactly the same manner as the angular adjustment of side panel 24 . Referring particularly to FIG. 4A , when the side panel 24 , along with shaft 42 is rotated approximately 30 degrees into the position shown in FIG. 4B , flat 50 on the band 44 will snap into engagement with detent, or flat 42 a on the shaft 42 , thereby locking the side panel into the angularly inwardly extending position. Further rotation of the side panel, along with shaft 42 , will cause the flat 50 to move out of engagement with detent 42 a and into the position shown in FIG. 4C . In this position, the flat 50 on the band will snap into engagement with detent, or flat 42 b provided on shaft thereby locking the side panel into the approximately 90 degree angularly inwardly extending position shown in FIG. 4C .
Referring next to FIGS. 8 through 12 , an alternate form of seat headrest of the invention is there illustrated and generally designated by the numeral 54 . This alternate form of the seat headrest is similar in many respects that illustrated in FIGS. 1 through 7 and like numbers are used in FIGS. 8 through 12 to identify like components. Seat headrest 54 here comprises a support assembly 56 that includes a central head support member 58 , a first lateral, or side panel 20 that is connected to member 58 by a novel friction hinge 22 and a second lateral, or side panel 24 that is connected to central member 58 by a novel friction hinge 22 . As before, to reduce the weight of the central head support member 58 , and side panels 20 and 24 , each is provided with a multiplicity of weight reduction apertures 25 .
As in the earlier described embodiment of the invention, side panels 20 and 24 are pivotally movable from an at rest position wherein they are substantially coplanar with the central head support member 58 to selected angularly extending forward positions. Angular movement of side panels 20 and 24 is accomplished substantially identical manner to that described in connection with the embodiment of FIGS. 1 through 7 .
The primary difference between this latest embodiment of the invention and that illustrated in FIGS. 1 through 7 resides in the fact that support assembly 56 is pivotally connected to a mounting assembly 60 that is of a slightly different construction from mounting assembly 26 ( FIG. 10 ). More particularly, support assembly 56 is pivotally connected to mounting assembly 60 by a conventional, generally commercially available tilt hinge assembly 62 that includes a first leaf 62 a that is connected to the front surface of head support member 58 (see FIG. 8 ) and a second connector assembly 62 b that is connected to the rear surface of the central panel (see FIG. 10 ). Tilt hinge assembly 62 includes a shaft 63 a and a pair of bands 63 b.
Second connector assembly 62 b is, connected to a connector member 64 which forms a part of mounting assembly 60 (see FIG. 10 ). As indicated in FIG. 10 , connector member 64 is connected to a connector member 66 which is, in turn, connected to an elongated guide 68 . Guide 68 is of similar construction to guide 28 and can be connected to a seat “S” by any suitable means. Elongated guide 68 includes oppositely disposed guide rails 68 a that are adapted to be rollably engaged by two pairs of spaced apart roller assemblies 38 that are mounted on central head support member 58 . The roller assemblies 38 , each of which are of identical construction, include grooved rollers 38 a that roll along guide rails 68 a so that the headrest assembly 56 can be adjustably moved upwardly and downwardly so as to enable the desired adjustment in the height of the assembly. A connector member 40 spans the spaced apart rollers and defines a channel 71 within which guide 68 is disposed (see also FIG. 9 ).
Forming an important aspect of the headrest assembly of this latest form of the invention is a resistance imparting spring for imparting resistance to the movement of headrest assembly 56 upwardly and downwardly relative to guide 68 . As before, this novel resistance imparting spring comprises a uniquely configured leaf spring 43 that includes a transverse connector portion 43 a that is affixed to connector member 66 and a downwardly extending central portion 43 b that extends into channel 41 . When the headrest assembly 56 is mounted on guide 68 in the manner shown in the drawings, the central portion 43 b of the spring will be yieldably deformed so that it is brought into pressural engagement with the guide. With this construction, as the headrest assembly is moved upwardly and downwardly, the central portion 43 b of the spring will frictionally engage the surface of the guide 68 and will yieldably resist sliding movement of headrest assembly 56 relative to the guide. As before, guide 68 is connected to a connector member 30 which is connected to seat “S” in the manner illustrated FIG. 12 .
Having now described the invention in detail in accordance with the requirements of the patent statutes, those skilled in this art will have no difficulty in making changes and modifications in the individual parts or their relative assembly in order to meet specific requirements or conditions. Such changes and modifications may be made without departing from the scope and spirit of the invention, as set forth in the following claims.
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An adjustable headrest that provides both support and comfort to the user and one that can be used in connection with various types of passenger vehicles. The headrest includes slide mechanisms for permitting easy height adjustment of the headrest and also includes an adjustment mechanism for adjusting the headrest forwardly and rearwardly. Further, the headrest includes easily adjustable, wing-like, side-support members that are pivotally connected to a centrally located, vertically adjustable head support member by specially designed hinges.
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TECHNICAL FIELD
[0001] The present invention, relates to a carboxyl group-containing polymer composition. Specifically, the present invention relates to a carboxyl group-containing polymer composition useful as a raw material for detergent additives and the like.
BACKGROUND ART
[0002] Carboxyl group-containing polymers contained in carboxyl group-containing polymer compositions are useful polymers used in various industrial fields and are useful specifically for use in aqueous environment (e.g. dispersants, detergent compositions).
[0003] An example of conventional carboxyl group-containing polymers is a (meth)acrylic acid-based copolymer that includes 70 to 95 mol % of a structure unit (a) derived from a (meth)acrylic acid-based monomer (A) and 5 to 30 mol % of a structure unit (b1) derived from a (meth)allyl ether monomer (B1) and is terminated with a sulfonic acid group at one or both ends of its main chain (Patent Literature 1). Patent Literature 1 states that this (meth)acrylic acid-based copolymer exhibits excellent chelating ability, dispersibility, and gel resistance.
[0004] Another example is a scale inhibitor that contains a (meth)acrylic acid-based polymer including a structure unit (a) derived from a (meth)acrylic acid-based monomer (A), a structure unit (b) derived from a sulfonic acid-based monomer (B), and a structure unit (c) derived from another (meth)acrylic acid-based monomer (C) (Patent Literature 2). Patent Literature 2 states that this scale inhibitor containing a (meth)acrylic acid-based polymer has an excellent capacity to inhibit scale of calcium phosphate.
CITATION LIST
Patent Literature
[0005] Patent Literature 1: JP-A 2002-3536
[0006] Patent Literature 2: JP-A 2009-28618
SUMMARY OF INVENTION
Technical Problem
[0007] As described above, carboxyl group-containing polymers of various structures arc under examination.
[0008] Currently, there is a water saving trend in fabric washing (e.g. use of used water in bathtub for fabric washing) with a recent growing concern of consumers for environmental problems. The use of used water in bathtub for fabric washing has disadvantages such as attachment or soil components in the water to fibers in fabric washing, and condensed hardening components in the water as a result of heating the water several times. Therefore, much higher performance than before is required to prevent soil components from reattaching to fibers (referred to as anti-soil redeposition ability) in fabric washing using harder water.
[0009] However, not all conventional carboxyl group-containing polymers and compositions containing these polymers meet the recent demanding need, that is, high performance in aqueous environment enough, and therefore further improvements are required to provide polymers and compositions that meet the recent need and are suitably used as higher-performance detergent additives.
[0010] The present invention has been made in view of this problem and an object of the present invention is to provide a composition containing a carboxyl group-containing polymer which exhibits excellent anti-soil redeposition ability in fabric washing.
Solution to Problem
[0011] The present inventors examined compositions that can be suitably used as detergent additives and the like and found that a composition that contains a carboxyl group-containing polymer including specific ratios of a structure unit derived from an acrylic acid-based monomer and a structure unit derived from a sulfonic acid group-containing monomer exhibits notable anti-soil redeposition ability even in hard water.
[0012] Additionally, such a composition was found to be preeminent in this performance when it contains a specific level of an adduct of a hydrogen sulfite to the acrylic acid-based monomer (A), and thus found to be suited as a detergent additive which meets the recent need. Thus, the present inventors found a way to solve the above problem and therefore completed the present invention.
[0013] Specifically, the present invention provides a carboxyl group-containing polymer composition containing a carboxyl group-containing polymer. The carboxyl group-containing polymer includes a structure unit (a) derived from an acrylic acid-based monomer (A) at a level of from 60 to 70% by mass and a structure unit (b) derived from a sulfonic acid group-containing monomer (B) at a level of from 30 to 40% by mass based on 100% by mass of all structure units derived from all monomers in the carboxyl group-containing polymer, and has a weight average molecular weight of 23,000 to 50,000. The carboxyl group-containing polymer composition further contains an adduct of a hydrogen sulfite to the acrylic acid-based monomer (A), and the adduct is present at a level of 0.3 to 5% by mass based on 100% by mass of the solids content of the carboxyl group-containing polymer composition.
[0014] The following description is offered to describe the present invention in detail.
[0015] It should be understood that combinations of two or more of preferable modifications of the present invention described herein are also preferable modifications of the present invention.
[Carboxyl Group-Containing Polymer]
[0016] The carboxyl group-containing polymer composition of the present invention is a composition that contains a carboxyl group-containing polymer. First, the carboxyl group-containing polymer is described.
[0017] The carboxyl group-containing polymer (hereinafter, also simply referred to as “polymer”) includes a structure unit (a) at a level of from 60 to 70% by mass and a structure unit (b) at a level of from 30 to 40% by mass based on 100% by mass of all structure units derived from all monomers in the carboxyl group-containing polymer (hereinafter, also simply referred to as “all the structure units”). The structure unit (a) is derived from an acrylic acid-based monomer (A), and the structure unit (b) is derived from a sulfonic acid group-containing monomer (B). The weight average molecular weight of the carboxyl group-containing polymer is 23,000 to 50,000.
<Acrylic Acid-Based Monomer (A)>
[0018] The carboxyl group-containing polymer herein is a polymer essentially including the structure unit (a) derived from an acrylic acid-based monomer (A) (hereinafter, also simply referred to as monomer (A)).
[0019] Examples of the acrylic acid-based monomer (A) include monomers represented by the formula (1):
[0000]
[0000] wherein R 1 represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group.
[0020] Examples of the structure unit (a) derived from an acrylic acid-based monomer (A) include a structure derived from a monomer (A) in which the carbon-carbon, double bond is converted to a single bond. Specific examples thereof are those represented by the formula (2):
[0000]
[0000] wherein R 1 is defined as above.
[0021] Due to the presence of the structure unit (a), the carboxyl group-containing polymer can act as a high-performance dispersant and exhibit notable anti-soil redeposition ability against hydrophobic soils.
[0022] When R 1 in the formulas (1) and (2) is a metal atom, an ammonium group, or an organic amine group, the acrylic acid-based monomer (A) is a metal salt, an ammonium salt, or an organic amine salt of acrylic acid.
[0023] Examples of metal atoms for R 1 in the formulas (1) and (2) include alkali metal atoms such as lithium, sodium, and potassium; and alkaline earth metal atoms such as magnesium and calcium; and aluminum and iron.
[0024] Examples of organic amines for R 1 include alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine; alkylamines such as monoethylamine, diethylamine, and triethylamine; and polyamines such as ethylenediamine and triethylenediamine.
[0025] R 1 is preferably a hydrogen atom, an alkali metal, or an ammonium group because they have a greater effect of improving the anti-soil redeposition ability of the polymer. R 1 is more preferably a hydrogen atom, sodium, potassium, or an ammonium group, and still more preferably a hydrogen atom or sodium.
[0026] Specific examples of the acrylic acid-based monomer (A) include acrylic acid and salts thereof. The acrylic acid-based monomer (A) is preferably acrylic acid or the sodium salt thereof.
[0027] The wording “the carboxyl group-containing polymer of the present invention contains a structure unit (a) derived from an acrylic acid-based monomer (A)” means that the prepared polymer contains a structure unit represented by the formula (2). Specifically, the “structure unit (a) derived from an acrylic acid-based monomer (A)” herein is intended to include structure units introduced in a step before a polymerization reaction and structure units introduced in a step after a polymerization reaction, and refers to, for example, a structure unit that is incorporated in the polymer by synthesizing the acrylic acid-based monomer (A), and then copolymerizing the acrylic acid-based monomer (A) with another monomer, or a structure unit that is completed by forming the main chain of the carboxyl group-containing polymer by copolymerization, and then introducing a side chain of a specific structure thereto.
[0028] The carboxyl group-containing polymer of the present invention may include only one structure unit (a) or may include two or more structure units (a).
[0029] The structure unit (a) is contained at a level of 60 to 70% by mass based on 100% by mass of all the structure units derived from ail the monomers in the carboxyl group-containing polymer (i.e. the total amount of the structure unit (a), and structure units (b) and (a) described below). The polymer which includes the structure unit (a) at a level within this range is capable of successfully interacting with soil components when the composition of the present invention which contains the polymer is used as a detergent builder and the like. Therefore, the polymer can disperse soil particles by the interaction and exhibit anti-soil redeposition ability.
[0030] The level of the structure unit (a) is preferably 62 to 70% by mass, more preferably 64 to 70% by mass, and still more preferably 66 to 70% by mass.
[0031] In the present invention, when the mass ratio (% by mass) of the structure unit (a) to all the structure units derived from all the monomers in the carboxyl group-containing polymer is calculated, the structure unit (a) is treated as its corresponding acid. In the case of the structure unit —CH 2 —CH(COONa)- derived from sodium acrylate, the mass ratio (% by mass) of the structure unit derived from the corresponding acid (acrylic acid), that is, the mass ratio (% by mass) of the structure unit —CH 2 —CH(COOH)— is calculated. Likewise, when the mass ratio (% by mess) of the acrylic acid-based monomer (A) to all the monomers is calculated, the acrylic acid-based monomer (A) is treated as its corresponding acid. For example, to determine the mass ratio of sodium acrylate, the mass ratio (% by mass) of the corresponding acid (acrylic acid) is calculated instead.
[0032] The method for preparing the acrylic acid-based monomer (A) is not particularly limited.
<Sulfonic Acid Group-Containing Monomer (B)>
[0033] The carboxyl group-containing polymer herein is a polymer essentially including a structure unit (b) derived from a sulfonic acid group-containing monomer (B) (hereinafter, also referred to as monomer (B)) as well.
[0034] Examples of the sulfonic acid group-containing monomer (B) include monomers represented by the formula (3):
[0000]
[0000] wherein R 2 represents a hydrogen atom or a methyl group; R 3 represents a CH 2 group, a CH 2 CH 2 group, or a direct bond; R 4 and R 5 independently represent a hydroxyl group or —SO 3 Z; Z represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group; and at least one of R 4 and R 5 is —SO 3 Z.
[0035] Examples of the structure unit (B) derived from a sulfonic acid group-containing monomer (B) include a structure derived from a monomer (B) in which the carbon-carbon double bond is converted to a single bond. Specific examples thereof are those represented by the formula (4):
[0000]
[0000] wherein R 2 , R 3 , R 4 , and R 5 are all defined as above.
[0036] Due to the presence of the structure unit (b), the carboxyl group-containing polymer can act as a high-performance dispersant for tough soils, and exhibit notable anti-soil redeposition ability against hydrophobic soils.
[0037] R 2 in the formulas (3) and (4) represents a hydrogen atom or a methyl group, and is preferably a hydrogen atom.
[0038] R 3 represents a CH 2 group, a CH 2 CH 2 group, or a direct bond, and is preferably a CH 2 group.
[0039] R 4 and R 5 independently represent a hydroxyl group or —SO 3 Z, and at least one of R 4 and R 5 is —SO 3 Z. In order to more successfully ensure the effect of the present invention enough, it is preferable that only one of R 4 and R 5 is —SO 3 Z.
[0040] Z represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group.
[0041] In the case that Z is a metal atom, an ammonium group, or an organic amine group, —SO 3 Z is a metal salt, an ammonium salt, or an organic amine salt of sulfonic acid.
[0042] Examples of metal atoms and organic amines for Z include the same metal atoms and organic amines listed above for R 1 . Z is preferably a hydrogen atom, an alkali metal atom, or an ammonium group, more preferably a hydrogen atom, sodium, or potassium, and still more preferably a hydrogen atom or sodium.
[0043] Specific examples of the sulfonic acid group-containing monomer (B) represented by the formula (3) include 3-(meth)allyloxy-2-hydroxypropanesulfonic acid, 3-(meth)allyloxy-1-hydroxypropanesulfonic acid, and salts of these. In order to more successfully ensure the effect of the present invention enough, 3-(meth)allyloxy-2-hydroxypropanesulfonic acid and salts thereof are preferably, and 3-allyloxy-2-hydroxypropanesulfonic acid and the sodium salt thereof are more preferable.
[0044] The wording “the carboxyl group-containing polymer of the present invention contains a structure unit (b) derived from a sulfonic acid group-containing monomer (B)” means that the prepared polymer contains a structure unit represented by the formula (4). Specifically, the “structure unit (b) derived from a sulfonic acid group-containing monomer (B)” herein is intended to include structure units introduced in a step before a polymerization reaction and structure units introduced in a step after a polymerization reaction, and refers to, for example, a structure unit that is incorporated in the polymer by synthesizing the sulfonic acid group-containing monomer (B), and then copolymerizing the sulfonic acid group-containing monomer (B) with another monomer, or a structure unit that is completed by forming the main chain of the carboxyl group-containing polymer by copolymerization, and then introducing a side chain of a specific structure thereto.
[0045] The carboxyl group-containing polymer of the present invention may include only one structure unit (b) or two or more structure units (b).
[0046] The structure unit (b) is contained at a level of 30 to 40% by mass based on 100% by mass of all the structure units derived from all the monomers in the carboxyl group-containing polymer (i.e. the total amount of the structure units (a) and (b) and structure unit (e) described below). The polymer which includes the structure unit (b) at a level within this range is capable of successfully interacting with soil components when the composition of the present invention containing the polymer is used as a detergent builder and the like. Therefore, the polymer can disperse soil particles by the interaction and exhibit anti-soil redeposition ability.
[0047] The level of the structure unit (b) is preferably 30 to 38% by mass, more preferably 30 to 36% by mass, and still more preferably 30 to 34% by mass.
[0048] In the present invention, when the mass ratio (% by mass) of the structure unit (b) to all the structure units derived from all the monomers in the carboxyl group-containing polymer is calculated, the structure unit (b) is treated as its corresponding acid. In the case of a structure unit derived from sodium 3-allyloxy-2-hydroxypropanesulfonate, the mass ratio (% by mass) of the structure unit derived from the corresponding acid (3-allyloxy-2-hydroxypropanesulfonic acid) is calculated. Likewise, when the mass ratio (% by mass) of the sulfonic acid group-containing monomer (B) to all the monomers is calculated, the sulfonic acid group-containing monomer (B) is treated as its corresponding acid. For example, to determine the mass ratio of sodium 3-allyloxy-2-hydroxypropanesulfonate, the mass ratio (% by mass) of the corresponding acid (3-allyloxy-2-hydroxypropanesulfonic acid) is calculated instead.
[0049] The method for preparing the sulfonic acid group-containing monomer (B) is not particularly limited, and any suitable method can be used for the preparation. For example, a method for adding a hydrogen sulfite to the glycidyl group of (meth)allylglycidyl ether is mentioned as an example of a simple method for the preparation.
<Other Monomers>
[0050] The carboxyl group-containing polymer of the present invention may include structure unit(s) (e) derived from other monomer(s) (E) (monomer(s) other than the acrylic acid-based monomer (A) and the sulfonic acid group-containing monomer (B)). The carboxyl group-containing polymer may contain only one structure unit (e) or two or more structure units (e).
[0051] The other monomer(s) (E) (hereinafter, also referred to as monomer(s) (E)) are not particularly limited, provided that they are copolymerizable with the monomers (A) and (B). Appropriate ones can be selected by considering desired effects.
[0052] Specific examples of other monomers (E) include carboxyl group-containing monomers other than the monomer (A) such as methacrylic acid, maleic acid, crotonic acid, itaconic acid, 2-methyleneglutaric acid, and salts of these; sulfonic acid group-containing monomers other than the monomer (B) such as vinylsulfonic acid, (meth)allylsulfonic acid, 1-acrylamido-1-propanesulfonic acid, styrenesulfonic acid, and salts of these; polyalkylene glycol chain-containing monomers such as monomers obtained by adding alkylene oxides to unsaturated alcohols (e.g. (meth)allylalcohol, isoprenol) and (meth)acrylic acid esters of alkoxyalkylene glycols; vinyl aromatic compound-based monomers having a heterocyclic aromatic hydrocarbon group such as vinyl pyridine and vinyl imidazole; amino group-containing monomers such as dialkylaminoalkyl (meth)acrylates (e.g. dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl acrylate), dialkylaminoalkyl (meth)acrylamides (e.g. dimethylaminoethyl acrylamide, dimethylaminoethyl methacrylamide, dimethylaminopropyl acrylamide), allylamines including diallylamine and diallylalkylamines (e.g. diallyldimethylamine), and quaternized compounds of these; N-vinyl monomers such as N-vinyl pyrrolidone, N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylformamide, N-vinyl-N-methylacetamide, and N-vinyloxazolidone; amide-based monomers such as (meth)acrylamide, N,N-dimethylacrylamide, and N-isopcopylacrylamide; hydroxyl group-containing monomers such, as (meth)allylalcohol and isoprenol; alkyl (meth)acrylate-based monomers such as butyl(meth)acrylate, 2-ethylhexyl (meth)acrylate, and dodecyl (meth)acrylate; hydroxyalkyl (meth)acrylate-based monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-hydroxyhexyl (meth)acrylate; vinylaryl monomers such as styrene, indene, and vinylaniline; and isobutylene and vinyl acetate.
[0053] The quaternized compounds can be obtained by the reaction between the amino group-containing monomers and common quaternizing agents. Examples of the quaternizing agents include alkyl halides and dialkyl sulfates.
[0054] The structure units (e) derived from other monomers (E) refer to structure units derived from the monomers (E) in each of which the carbon-carbon double bond is converted to a single bond. The wording “the carboxyl group-containing polymer of the present invention contains structure unit(s) (e) derived from other monomer(s) (E)” means that the prepared polymer contains structure unit(s) in which the carbon-carbon double bond in the monomer(s) (E) is converted to a single bond.
[0055] The level of the structure unit(s) (e) derived from other monomer(s) (E), which are optional components, is preferably 0 to 10% by mass based on 100% by mass of all the structure units derived from all the monomers in the carboxyl group-containing polymer (i.e. the total amount of the structure units (a), (b), and (e)). The level is more preferably 0 to 5% by mass, and still more preferably 0% by mass.
[0056] In the case that the structure unit (e) is a structure unit derived from an amino group-containing monomer, the mass ratio of this structure unit to all the structure units derived from all the monomers and the mass ratio of the amino group-containing monomer to all the monomers are calculated by treating the structure unit and the monomer as the corresponding unneutralized amine. For example, in the case that the other monomer (E) is vinylamine hydrochloride, the mass ratio (% by mass) of its corresponding unneutralized amine, that is, the mass ratio of vinylamine is calculated instead.
[0057] The mass ratios (% by mass) of quaternized amino group-containing monomers and structure units derived from these are calculated without counting the mess of counteranions.
[0058] In the case that the structure unit (e) is a structure unit derived from an acid group-containing monomer, the mass ratio (% by mass) of the structure unit to all the structure units derived from all the monomers is calculated by treating the structure unit as its corresponding acid. The mass ratio (% by mass) of the acid group-containing monomer to all the monomers is also calculated by treating the monomer as its corresponding acid.
<Physical Properties of Carboxyl Group-Containing Polymer>
[0059] The carboxyl group-containing polymer of the present invention contains the structure units (a) and (b) at specific levels defined above, and optionally contains the structure unit(s) (e) at a specific level defined above. These structure units may be arranged in either a block or random fashion.
[0060] The weight average molecular weight of the carboxyl group-containing polymer is 23,000 to 50,000. If the weight average molecular weight is in this range, the anti-soil redeposition ability is improved. The weight average molecular weight is preferably 23,000 to 45,000, more preferably 24,000 to 40,000, still more preferably 25,000 to 38,000, and particularly preferably 27,000 to 33,000.
[0061] The weight average molecular weight used herein is determined by GPC (gel permeation chromatography) and can be determined with the device under the measurement conditions described in Examples below.
[0062] The carboxyl group-containing polymer of the present invention and the composition of the present invention have high anti-soil redeposition ability, and preferably have an anti-soil redeposition ratio of at least 37%. The anti-soil redeposition ratio is more preferably at least 38%, and still more preferably at least 40%.
[0063] The anti-soil redeposition ratio can be measured by the procedure described in Examples below.
[Method for Preparing Carboxyl Group-Containing Polymer]
[0064] The carboxyl group-containing polymer of the present invention can be prepared by copolymerizing monomer materials which essentially include specific amounts of an acrylic acid-based monomer (A) represented by the formula (1) and a sulfonic acid group-containing monomer (B) represented by the formula (3), and optionally include a specific amount of other monomer(s) (E).
[0065] In the method for preparing the carboxyl group-containing polymer of the present invention, the amounts of the respective monomers need in the polymerization are specifically as follows. The amount of the monomer (A) is 60 to 70% by mass, and the amount of the monomer (B) is 30 to 40% by mass based on 100% by mass of all the monomers (the monomers (A), (B), and (E)). The use of the monomer (A) in an amount of less than 60% by mass may result in reduced absorbability to hydrophilic soils, and therefore may result in reduced anti-soil redeposition ability and detergency against hydrophilic soils. The use of the monomer (B) in an amount of leas than 30% by mass may result in reduced detergency against tough soils.
[0066] The amounts of the monomers (A) and (B) are preferably 62to 70% by mass and 30 to 33% by mass, respectively, more preferably 64 to 70% by mass and 30 to 36% by mass, respectively, and still more preferably 66 to 70% by mass and 30 to 34% by mass, respectively.
[0067] In addition, the monomer(s) (E) may be used in an amount of 0 to 10% by mass based on 100% by mass of all the monomers (the monomers (A), (B), and (E)). The amount is more preferably 0 to 5% by mass, and still more preferably 0% by mass.
[0068] The polymerization method to obtain the carboxyl group-containing polymer of the present invention is not particularly limited, and a common polymerization method or a modified method thereof can be used. Examples of polymerization methods include radical polymerization. Specific examples thereof include oil-in-water emulsion polymerization, water-in-oil emulsion polymerization, suspension polymerization, dispersion, polymerization, precipitation polymerization, solution polymerization, aqueous solution polymerization, and bulk polymerization. Among these polymerization methods, solution polymerization is preferable because it is a highly safe method and provides production (polymerization) cost savings.
[0069] In the case of solution polymerization, the monomers are polymerized in a solvent.
[0070] The solvent may be one consisting of an organic solvent but is preferably one containing water. The solvent preferably contains at least 50% by mass of water based on the total amount (100% by mass) of the solvent, and the amount of water is more preferably at least 80% by mass. In particular, 100% by mass of water is preferable. Examples of organic solvents that can be used alone or in combination with water include aqueous organic solvents such as lower alcohols (e.g. ethanol, isopropanol), amides (e.g. N,N-dimethylformamide), ethers (e.g. diethyl ether, dioxane), glycol, glycerin, and polyethylene glycols.
[0071] Only one solvent may be used alone, or two or more solvents may be used in combination.
[0072] The amount of the solvent is preferably 40 to 300 parts by mass, more preferably 45 to 200 parts by mass, and further more preferably 50 to 150 parts by mass per 100 parts by mass of all the monomers (the monomers (A), (B), and (E)). The use of the solvent in an amount of less than 40 parts by mass per 100 parts by mass of all the monomers may result in production of a polymer with a high molecular weight. The use of the solvent in an amount of more than 300 parts by mass per 100 parts by mass of all the monomers may result in a low concentration of the resulting polymer, and therefore a step for removing the solvent may be required in some cases.
[0073] A portion or all of the solvent is charged in a reaction vessel at an initial stage of the polymerization, and a remaining portion of the solvent may be added (dropwise) to the reaction system during the polymerization reaction. Alternatively, the monomers and agents such as a polymerization initiator may be dissolved in the solvent and this solution containing these components may be added (dropwise) to the reaction system.
[0074] The reaction by solution polymerization is not particularly limited and may be carried out in a common way. The reaction is typically carried out, for example, by charging the solvent in the reaction system, and adding dropwise solutions containing the monomers and a solution containing a polymerization initiator (hereinafter, also referred to as initiator). In such a case, the concentration of each solution to be added dropwise is not particularly limited, and may be appropriately determined.
[0075] For example, in the case that solutions containing the monomers and a solution containing an initiator are added dropwise to the solvent set in the reaction system, the monomer (A), the monomer (B), the monomer(s) (E) (if necessary), the initiator, and other additives (if necessary) may be dissolved in solvents, respectively, and the polymerization may be carried out by adding (dropwise) the solutions to the reaction system during the polymerization in an appropriate manner. In this case, a portion or all of the monomer (A) may be charged in the reaction system before the start of the polymerization.
<Polymerization Initiator>
[0076] In the preparation method, commonly used polymerization initiators may be used. Specifically, suitable examples thereof include persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; azo compounds such as 2,2′-azobis(2-amidinopropane)hydrochloride, 4,4′-azobis-4-cyanovaleric acid, azobis isobutyronitrile, and 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile); and organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, di-t-butyl peroxide, and cumene hydroperoxide. Persulfates and 2,2′-azobis(2-amidinopropane)hydrochloride are more preferable among these polymerization initiators. Any of these polymerization initiators may be used alone, or two or more of these may be used in combination.
<Chain Transfer Agent>
[0077] In the preparation method, a chain transfer agent may be used as a molecular weight controlling agent for the polymer. The use of a chain transfer agent advantageously prevents an increase in the molecular weight of the resulting polymer over a certain level and therefore results in more efficient production of a carboxyl group-containing polymer having low-molecular weight.
[0078] A hydrogen sulfite and/or a compound capable of producing a hydrogen sulfite is/are used as chain transfer agent(s) in the preparation method. In this case, it is preferable to use a polymerization initiator in addition to the hydrogen sulfite and/or the compound capable of producing a hydrogen sulfite. Additionally, a heavy metal ion may be used in combination as a reaction accelerator as described below.
[0079] If a hydrogen sulfite and/or a compound capable of producing a hydrogen sulfite is/are used as chain transfer agent(s), the resulting polymer is terminated with a sulfonic acid (salt) group at one or both ends of its main chain.
[0080] Examples of compounds capable of producing a hydrogen sulfite include pyrosulfurous acid (salts), dithionous acid (salts), and sulfurous acid (salts). Particularly, pyrosulfurous acid (salts) are preferable.
[0081] The salts are preferably salts with metal atoms, ammonium, and organic amines.
[0082] Examples of the metal atoms include monovalent alkali metal atoms such as lithium, sodium, and potassium; divalent alkaline earth metal atoms such as calcium and magnesium; and trivalent metal atoms such as aluminum and iron.
[0083] Examples of the organic amines include alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine; and triethylamine.
[0084] Among hydrogen sulfites and the compounds capable of producing a hydrogen sulfite, hydrogen sulfites are preferable.
[0085] Examples of hydrogen sulfites include sodium hydrogen sulfite, potassium hydrogen sulfite, and ammonium hydrogen sulfite. Particularly, sodium hydrogen, sulfite is more preferable.
[0086] Specific examples of the compounds capable of producing a hydrogen sulfite include sodium pyrosulfite and potassium pyrosulfite; sodium dithionite and potassium dithionite; and sodium sulfite, potassium sulfite, and ammonium sodium sulfite. Particularly, sodium, pyrosulfite is more preferable.
[0087] Any of these hydrogen sulfites and compounds capable of producing a hydrogen sulfite may be used alone, or two or more of these may be used in combination.
[0088] In addition to a hydrogen sulfite and/or a compound capable of producing a hydrogen sulfite, any of the following compounds may also be used as a chain transfer agent. Examples of such chain transfer agents include thiol-based chain transfer agents such as mercaptoethanol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, octyl 3-mercaptopropionate, 2-mercaptoethansulfonic acid, and n-dodecyl mercaptan; halides such as carbon tetrachloride, methylene chloride, bromoform, and bromotrichloroethane; secondary alcohols such as isopropanol and glycerin; and lower oxides such as phosphorous acid, bypophosphorous acid, and salts of these (e.g. sodium hypophosphite, potassium hypophosphite). Any of these chain transfer agents may be used alone, or two or more of these may be used in combination.
<Reaction Accelerator>
[0089] In the preparation method, a reaction accelerator may be added to reduce the amount of agents used in the reaction such as the polymerization initiator. Examples of reaction accelerators include heavy metal ions.
[0090] The term “heavy metal ions” used herein is intended to include metal ions having a specific gravity of not less than 4 g/cm 3 . Preferred examples of heavy metals for the heavy metal ions include iron, cobalt, manganese, chromium, molybdenum, tungsten, copper, silver, gold, lead, platinum, iridium, osmium, palladium, rhodium, and ruthenium. Any of these heavy metals may be used alone, or two or more of these may be used in combination. Among these, iron is more preferable.
[0091] The ionic valency of the heavy metal ions is not particularly limited. For example, when iron is used as a heavy metal, the reaction accelerator may include iron ion in the Fe 2+ form, or Fe 3+ form, or may include iron ion in both forms.
[0092] These heavy metal ions may be used in any forms, provided that they are present in ion forms. For handleability, these heavy metal ions are preferably used in solution forms obtained by dissolving heavy metal compounds. The heavy metal compounds are any compounds, provided that they each contain a desired heavy metal that is to be captured in a polymerization initiator. Appropriate one can be selected according to a polymerization initiator used in combination.
[0093] When iron ion is used as a heavy metal ion, preferred examples of heavy metal compounds include Mohr's salt (Fe(NH 4 ) 2 (SO 4 ) 2 .6H 2 O), ferrous sulfate heptahydrate, ferrous chloride, and ferric chloride. When manganese ion is used as a heavy metal ion, manganese chloride or the like is suitable. All of these are water-soluble compounds and therefore are used in aqueous solution forms and easy to handle. Solvents used to prepare a solution of a heavy metal compound are not limited to water, provided that they dissolve the heavy metal compound and do not inhibit the polymerization reaction in the preparation of the carboxyl group-containing polymer of the present invention.
[0094] A heavy metal ion may be added in any manner. Preferably, all of the heavy metal ion is added before the completion of addition of the monomers. More preferably, the heavy metal ion is charged all at once at the start of the reaction.
[0095] The amount of the heavy metal ion is preferably 0.1 to 10ppm per the total amount of the polymerization reaction solution at the completion of the polymerization. If the amount of the heavy metal ion is less than 0.1 ppm, the effect by the heavy metal ion may not be provided enough. If the amount of the heavy metal ion is more than 10 ppm, the color tone of the resulting polymer may be deteriorated. Furthermore, polymers produced with excess heavy metal ions may cause colored soils when used as detergent builders.
[0096] The term “at the completion ex the polymerization” means the time when the polymerization reaction in the polymerization reaction solution substantially ends such that the desired polymer is provided. For example, in the case that the polymer produced in the polymerization reaction solution is neutralized, with an acid component, the amount of the heavy metal ion is determined based on the total amount of the polymerization reaction solution after the neutralization. In the case that two or more heavy metal ions are contained, the total amount of the heavy metal ions are within the above range.
[0097] In the preparation method, other compounds such as catalysts for decomposing the polymerization initiator and reducing compounds may be added in the reaction system upon the polymerization reaction in addition to the above-mentioned compounds.
[0098] Examples of catalysts for decomposing the polymerization initiator include halogenated metals such as lithium chloride and lithium bromide; metal oxides such as titanium oxide and silica dioxide; metal salts of inorganic acids such as hydrochloric acid, hydrobromic acid, perchloric acid, sulfuric acid, and nitric acid; carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, and benzoic acid, and esters and metal salts thereof; and heterocyclic amines such as pyridine, indole, imidazole, and carbazole, and derivatives thereof. Any of these decomposition catalysts may be used alone, or two or more of these may be used in combination.
[0099] Examples of reducing compounds include organic metal compounds such as ferrocene; inorganic compounds capable of generating metal ions (e.g. iron, copper, nickel, cobalt, manganese ions) such as iron naphthenate, copper naphthenate, nickel naphthenate, cobalt naphthenate, and manganese naphthenate; inorganic compounds such as ether adducts of boron trifluoride, potassium permanganate, and perchloric acid; sulfur-containing compounds such as sulfur dioxide, sulfuric acid esters, thiosulfuric acid salts, sulfoxylates, benzene sulfinic acid and substituted compounds thereof, and analogues of cyclic sulfinic acids such as p-toluene sulfinic acid; nitrogen-containing compounds such as hydrazine, β-hydroxyethylhydrazine, and hydroxylamine; aldehydes such as formaldehyde, propionaldehyde, n-butylaldehyde, isobutylaldehyde, and isovalerianaldehyde; and ascorbic acid. Any of these reducing compounds may be used alone, or two or more of these may be used in combination.
[0100] The combination of the chain transfer agent, the polymerization initiator, and the reaction accelerator is not particularly limited, and each of them can be suitably selected from the above examples. Either the polymerization initiator or the reaction accelerator may not be used. Preferred examples of the combination of the chain transfer agent, the polymerization initiator, and the reaction accelerator (written in this order) include sodium hydrogen sulfite/sodium persulfate/none, sodium hydrogen sulfite/none/Fe (ion), and sodium hydrogen sulfite/sodium persulfate/Fe (ion). The combinations of sodium, hydrogen sulfite/sodium persulfate/none and sodium hydrogen sulfite/sodium persulfate/Fe (ion) are more preferable, and the combination of sodium hydrogen sulfite/sodium persulfate/Fe (ion) is still more preferable. Here, “none” means that nothing is used as the corresponding agent.
<Amount of Polymerization Initiator and Other Agents>
[0101] The amount of the polymerization initiator is not particularly limited, provided that it is enough to initiate the copolymerization of the monomers. The amount of the polymerization initiator is preferably not more then 15 g per mol of all the monomers (the monomers (A), (B), and (E)), and more preferably 1 to 12 g.
[0102] When a persulfate is used as the polymerization initiator, the amount of the persulfate is preferably 1.0 to 5.0 g, and more preferably 2.0 to 4.0 g per mol of all the monomers. If the amount of the persulfate is less than 1.0 g, the resulting polymer tends to have a high molecular weight. On the other hand, addition of more than 5.0 g of the persulfate may not produce an effect proportional to the added amount and cause disadvantages such as low purity of the resulting polymer.
[0103] The method for adding the persulfate is not particularly limited, but it is preferable to almost continuously add the persulfate dropwise in an amount of at least 50% by mass of the predetermined required amount based on a consideration of its decomposability and the like. The amount is more preferably at least 80% by mass, and still more preferably 100% by mass (i.e. the persulfate is preferably all added dropwise). In the case that the persulfate is continuously added dropwise, the drop rate may be changed.
[0104] The drop-wise addition time is also not particularly limited. Since the persulfate is an initiator to be decomposed in a comparatively short time when the reaction is carried out under the suitable reaction conditions described below (e.g. temperature, pressure, pH), it is preferable to continue drop-wise addition of the persulfate until the completion of drop-wise addition of the monomers. It is more preferable to complete drop-wise addition of the persulfate within 30 minutes after the completion of drop-wise addition of the monomers, and is particularly preferable to complete the addition within 5 to 20 minutes after the completion of drop-wise addition of the monomers. Through such a process, the amount of residual monomers in the resulting polymer solution can be strikingly reduced.
[0105] Even if drop-wise addition of the initiator is completed before the completion of drop-wise addition of the monomers, the polymerization does not suffer from any disadvantages. The timing of the completion of drop-wise addition of the initiator can be determined according to the amount of residual monomers in the resulting polymer solution.
[0106] The starting timing of drop-wise addition of the polymerization initiator is not particularly limited and is appropriately determined. For example, drop-wise addition of the initiator may be started before drop-wise addition of the monomers. When two or more initiators are used in combination, a certain time after the start of drop-wise addition of one of the initiators or after the completion of drop-wise addition of this initiator, drop-wise addition of the other initiator(s) may be started. In each case, the starting timing of drop-wise addition of initiator(s) can be appropriately determined according to the decomposition speed of the initiator(s) and the reactivity of the monomers.
[0107] In the case that the polymerization initiator is added dropwise, the concentration of the initiator solution is not particularly limited and is preferably 5 to 60% by mass, and more preferably 10 to 50% by mass. In the polymerization reaction, when initiator concentrations is less than 5% by mass, the initiator solution contains a solvent at a high concentration, resulting in low concentrations of the monomers. In this case, the polymeriziability of the monomers may be strikingly low, and a remarkably large portion of the monomers may remain in the resulting polymer solution. Such concentrations are disadvantageous in terms of cost because of low transportation efficiency and productivity. Concentrations of more than 60% by mass are disadvantageous in terms of safety and handleability upon drop-wise addition.
[0108] The amount of the chain transfer agent is not particularly limited, provided that it is determined such that the monomers (A), (B), and (E) are allowed to polymerize well. The amount of the chain transfer agent is preferably 1 to 20 g, and more preferably 2 to 15 g per mol of all the monomers (the monomers (A), (B), and (E) ). If the amount of the chain transfer agent is less than 1 g, the molecular weight of the resulting polymer may not be controlled. On the other hand, the use of more than 20 g of the chain transfer agent may result in large amounts of impurities and therefore lead to low purity of the resulting polymer. Especially, when more than 20 g of a hydrogen sulfite is used, excess hydrogen sulfite is decomposed in the reaction system, which may disadvantageously result in generation of sulfur dioxide gas. In addition, the use of more than 20 g of the chain transfer agent may be disadvantageous in terms of cost.
[0109] A preferable combination of the initiator and the chain transfer agent is one or more of persulfates and one or more of hydrogen sulfites.
[0110] In this case, the blending ratio between the persulfate(s) and the hydrogen sulfite(s) is not particularly limited. Preferably, 0.5 to 5 parts by mass of the hydrogen sulfite(s) is/are used with respect to 1 part by mass of the persulfate(s). The lower limit of the amount of the hydrogen sulfite(s) is more preferably 1 part by mass, and is further more preferably 2 parts by mass with respect to 1 part by mass of the persulfate(s). The upper limit of the amount of the hydrogen sulfite(s) is more preferably 4 parts by mass, and further more preferably 3 parts by mass with respect to 1 part by mass of the persulfate(s). If less than 0.5 parts by mass of the hydrogen sulfite(s) is/are used with respect to 1 part by mass of the persulfate(s), the total initiator amount required to produce a lower-molecular weight polymer may increase. On the other hand, the use of more than 5 parts by mass of the hydrogen sulfite(s) may increase side reactions and therefore increase impurities produced in the side reactions.
[0111] The total amount of the chain transfer agent, the initiator, and the reaction accelerator is preferably 2 to 20 g per mol of all the monomers (A), (B), and (E). If these agents are used in an amount within this range, the carboxyl group-containing polymer of the present invention can be efficiently produced, and the molecular weight distribution of the polymer can be controlled within a desired range. The total amount of them is more preferably 4 to 18 g, and further more preferably 6 to 15 g.
[0112] In the preparation method, the monomers, the polymerization initiator, and the chain transfer agent may be added in a reaction vessel by continuous addition such as drop-wise addition and portion-wise addition. Each of them may be separately charged in the reaction vessel, or they may be mixed with other materials or in a solvent or the like in advance.
[0113] Specifically, these materials may be added by methods such as a method including charging all the monomers into the reaction vessel and adding the polymerization initiator to the reaction vessel to copolymerize the monomers; a method including charging a portion of the monomers into the reaction vessel, and adding the polymerization initiator and the remaining monomers continuously or portionwise (preferably, continuously) to the reaction vessel to copolymerize the monomers; and a method including charging a polymerization solvent into the reaction vessel, and adding all of the monomers and the polymerization initiator. Among these methods, the method including continuously adding the polymerization initiator and the monomers dropwise into the reaction vessel to copolymerize the monomers is preferable because it provides polymers having a narrow (sharp) molecular weight distribution and improves the dispersibility of soils and anti-soil redeposition ability. Polymerization may be batchwise polymerization or continuous polymerization.
<Polymerization Condition>
[0114] In the preparation method, the polymerization temperature is appropriately determined based on factors such as the polymerization method, the solvent, and the polymerization initiator. The polymerization temperature is preferably 25° C. to 200° C., more preferably 50° C. to 150*° C., furthermore preferably 60° C. to 120° C., and particularly preferably 80° C. to 110° C. At polymerization temperatures of lower than 25° C., the resulting polymer may have too high weight average molecular weight and larger amounts of impurities may be produced.
[0115] The polymerization temperature is not necessarily kept substantially constant throughout the polymerization reaction. For example, the temperature may be set at room temperature at the start of the polymerization, and increased to a target temperature at an appropriate temperature rising rate or over an appropriate temperature rising time, and then kept at the target temperature. Alternatively, the temperature may be altered (increased or decreased) with a lapse of time during the polymerization reaction depending on the method for the drop-wise addition of the monomers, the initiator, and the like. The term “polymerization temperature” used herein means the temperature of the react ion solution during the polymerization reaction. The method for measuring the polymerization temperature and means for controlling the polymerization temperature may be appropriately selected from any methods and controlling means. For example, the polymerization temperature can be measured with a common device.
[0116] The pressure during the polymerization in the preparation method is not particularly limited and can be suitably determined. For example, the pressure may be any of ambient pressure (atmospheric pressure), reduced pressure, and increased pressure. The atmosphere in the reaction system may be an air or inert gas atmosphere. In order to produce an inert gas atmosphere in the reaction system, the air in the system is replaced with an inert gas such as nitrogen before the start of the polymerization, for example. In this atmosphere, the atmospheric gas (such as oxygen gas) in the reaction system dissolves in the liquid phase and serves as a polymerization inhibitor.
[0117] In the preparation method, the solids content of the reaction solution (polymer solution) at the completion of addition of the monomers, the polymerization initiator and the chain transfer agent is preferably not less than 35% by mass. In the case that the solids content is less than 35% by mass, the productivity of the resulting polymer may not be strikingly improved. The solids content is more preferably 40 to 70% by mass, and further more preferably 45 to 65% by mass. When solids contents is not less than 35% by mass at the completion of addition of the monomers, the polymerization initiator and the chain transfer agent, the polymerization can be performed in one step in a high concentration reaction solution. Namely, the polymer can be effectively produced. In this case, steps such as a concentration step can be omitted, which in turn leads to remarkable improvement in the productivity of the polymer and suppresses an increase in the production cost.
[0118] The solids content can be calculated by sampling a portion of the reaction solution after completion of the drop-wise addition, and quantifying nonvolatile matters after one-hour treatment with a hot air dryer at 130° C.
[0119] In the preparation method, a maturing step may be performed to improve the polymerization rate of the monomers and the like after addition of all the raw materials. The maturing time is preferably 1 to 120 minutes, more preferably 5 to 60 minutes, and further more preferably 10 to 30 minutes. Maturing for less than one minute is insufficient such that portion of the monomers may remain. Consequently, impurities derived from the remaining monomers may deteriorate performance of the product. Maturing for more than 120 minutes may result in a colored polymer solution.
[0120] In the preparation method, the polymerization time is not particularly limited, and is preferably 30 to 420 minutes, more preferably 45 to 390 minutes, further more preferably 60 to 360minutes, and still further more preferably 90 to 300 minutes. The term “polymerization time” used herein means a time in which the monomers are being added, that is, a time from the start to the end of addition of the monomers.
[Carboxyl Group-Containing Polymer Composition]
[0121] The carboxyl group-containing polymer composition of the present invention contains the carboxyl group-containing polymer. The carboxyl group-containing polymer has a weight average molecular weight of 23,000 to 50,000, and includes a structure unit (a) derived from an acrylic acid-based monomer (A) at a level of from. 60 to 70% by mass and a structure unit (b) derived from a sulfonic acid group-containing monomer (B) at a level of from 30 to 40% by mass based on 100% by mass of all structure units derived from all monomers in the carboxyl group-containing polymer. The carboxyl group-containing polymer composition further contains an adduct of a hydrogen sulfite to the acrylic acid-based monomer (A), and the adduct is present at a level of 0.3 to 5% by mass based on 100% by mass of the solids content of the carboryl group-containing polymer composition.
[0122] The adduct of a hydrogen sulfite to the acrylic acid-based monomer (A) (hereinafter, also referred to as “hydrogen sulfite adduct”) is an impurity derived from the acrylic acid-based monomer (A) which remains unpolymerized although the above hydrogen sulfite and/or the compound capable of producing a hydrogen sulfite used as a chain transfer agent is added thereto. Specific examples thereof include 3-sulfopropionic acid (salts) and the like.
[0123] The level of the hydrogen sulfite adduct is, as described above, 0.3 to 5% by mass based on 100% by mass of the solids content of the carboxyl group-containing polymer composition. Due to the presence of the hydrogen sulfite adduct at a level in the above range, the detergency against muddy soils is improved. The level of the polymer is preferably 0.6 to 3% by mass, and more preferably 0.7 to 2% by mass.
[0124] The carboxyl group-containing polymer composition of the present invention may further contain other components other than the carboxyl group-containing polymer and the hydrogen sulfite adduct.
[0125] Examples of other components include, but are not limited to, residual polymerization initiator, residual monomers, by-products of the polymerization, and water. One or more of these components may be contained.
[0126] In terms of anti-soil redeposition ability, the carboxyl group-containing polymer composition of the present invention preferably contains 1 to 99.5% by mass of the carboxyl group-containing polymer based on 100% by mass of the carboxyl group-containing polymer composition. The level is more preferably 30 to 99% by mass, and still more preferably 40 to 98% by mass.
[0127] In one preferable modification, the carboxyl group-containing polymer composition contains 40 to 60% by mass of the carboxyl group-containing polymer and 35 to 59.5% by mass of water.
[0128] In terms of improvement in anti-soil redeposition ability of the carboxyl group-containing polymer composition of the present invention, the amount of the sulfonic acid group-containing monomer (B) remaining unreacted in the carboxyl group-containing polymer composition is preferably not more than 5000 ppm and more preferably not more than 2500ppm based on the solids content of the carboxyl group-containing polymer composition.
[Usage of Carboxyl Group-Containing Polymer Composition]
[0129] The carboxyl group-containing polymer composition of the present invention can be used as a coagulant, flocculating agent, printing ink, adhesive, soil control (modification) agent, fire retardant, skin care agent, hair care agent, additive for shampoos, hair sprays, soaps, and cosmetics, anion exchange resin, dye mordant and auxiliary agent for fibers and photographic films, pigment dispersant for paper making, paper reinforcing agent, emulsifier, preservative, softening agent for textiles and paper, additive for lubricants, water treatment agent, fiber treating agent, dispersant, additive for detergents, detergent builder, detergent composition, detergent, scale control agent (scale depressant), metal ion binding agent, viscosity improver, binder of any type, emulsifier, and the like.
[0130] The carboxyl group-containing polymer composition of the present invention has high performance when used in aqueous environment. In addition, the polymer composition has high hard water resistance, detergency, anti-soil redeposition ability, clay dispersibility, and interaction with surfactants and therefore exhibits better performance when used in water treatment agents, dispersants, detergent builders, detergent compositions, and detergents.
<Water Treatment Agent>
[0131] The carboxyl group-containing polymer composition of the present invention can be used in water treatment agents. In these water treatment agents, other additives such as polyphosphates, phosphonates, anti-corrosion agents, slime control agents, and chelating agents may be added, if necessary.
[0132] Such water treatment agents are useful for scale inhibition of cooling water circulation systems, boiler water circulation systems, seawater desalination plants, pulp digesters, black liquor condensing kettles and the like. In addition, any suitable water soluble polymer may be included within a range of not affecting the performance or effect of this composition.
<Further Treating Agent>
[0133] The carboxyl group-containing polymer composition of the present invention can be used in fiber treating agents. Such fiber treating agents contain at least one selected from the group consisting of dyeing agents, peroxides, and surfactants, in addition to the carboxyl group-containing polymer composition of the present invention.
[0134] In these fiber treating agents, the carboxyl group-containing polymer composition of the present invention preferably constitutes 1 to 100% by mass, and more preferably 5 to 100% by mass of the total amount. In addition, any suitable water soluble polymer may be included within a range of not affecting the performance or effect of this composition.
[0135] An example of the amounts of components in these fiber treating agents is described below. The fiber treating agents can be used in steps of scouring, dyeing, bleaching and soaping in fiber treatment. Examples of dyeing agents, peroxides, and surfactants include those commonly used in fiber treating agents.
[0136] Regarding the blending ratio (in solid content) between the carboxyl group-containing polymer composition of the present invention and at least one selected from the group consisting of dyeing agents, peroxides, and surfactants, for example, a composition that contains at least one selected from the group consisting of dyeing agents, peroxides, and surfactants at a level of 0.1 to 100 parts by mass per part by mass of the composition of the present invention is preferable as a fiber treatment agent in terms of improvement in whiteness, color uniformity; and dyeing fastness of fibers.
[0137] Such a fiber treating agent can be used for any suitable fibers including cellulosic fibers such as cotton and hemp, synthetic fibers such as nylon and polyester, animal fibers such as wool and silk thread, semisynthetic fibers such as rayon, and textiles and mixed products of these.
[0138] For a fiber treating agent used in a scouring step, an alkali agent and a surfactant are preferably used together with the composition of the present invention. For a fiber treating agent used in a bleaching step, a peroxide and a silicic acid-based agent (e.g. sodium silicate) which serves as a decomposition inhibitor for alkaline bleaches are preferably used with the composition of the present invention.
<Inorganic Pigment Dispersant>
[0139] The carboxyl group-containing polymer composition of the present invention can be used in inorganic pigment dispersants. In these inorganic pigment dispersants, other additives such as condensed phosphoric acid and salts thereof, phosphonic acid and salts thereof, and polyvinyl alcohol may be added, if necessary.
[0140] In these inorganic pigment dispersants, the carboxyl group-containing polymer composition of the present invention preferably constitutes 5 to 100% by mass of the total amount. In addition, any suitable water soluble polymer may be included within a range of not affecting the performance or effect of this composition.
[0141] These inorganic pigment dispersants exhibit good performance as inorganic pigment dispersants for heavy or light calcium carbonate and clay used for paper coating. For example, by adding such an inorganic pigment dispersing agent in a small amount to inorganic pigments and dispersing them in water, a highly concentrated inorganic pigment slurry such as a highly concentrated calcium carbonate slurry having low viscosity, high fluidity, and excellent temporal stability of these properties can be produced.
[0142] When such an inorganic pigment dispersant is used as a dispersant for inorganic pigments, the amount of the inorganic pigment dispersant is preferably 0.05 to 2.0 parts by mass per 100 parts by mass of inorganic pigments. The use of the inorganic pigment dispersant in an amount within this range provides a sufficient dispersion effect proportional to the added amount and is advantageous in terms of cost.
<Detergent Builder>
[0143] The carboxyl group-containing polymer composition of the present invention can be also used as a detergent builder. The detergent builder can be added to detergents for various usages such as detergents for clothes, tableware, cleaning, hair, bodies, toothbrushing, and vehicles.
<Detergent Composition>
[0144] The carboxyl group-containing polymer composition of the present invention can also be used in detergent compositions.
[0145] In the detergent compositions, the amount of the carboxyl group-containing polymer composition is not particularly limited, and the carboxyl group-containing polymer composition is preferably present at a level of 0.1 to 15% by mass, more preferably 0.3 to 10% by mass, and further more preferably 0.5to 5% by mass based on the total amount (100% by mass) to provide excellent detergent builder performance.
[0146] If intended for use in fabric washing, the detergent compositions typically contain surfactants and additives which are commonly used in detergents. Such surfactants and additives are not particularly limited and are appropriately selected based on common knowledge in the detergent industry. The detergent compositions may be powder detergent compositions or liquid detergent compositions.
[0147] One or more surfactants selected from the group consisting of anionic surfactants, nonironic surfactants, cationic surfactants, and amphoteric surfactants are used. When two or more of them are used in combination, the total amount of anionic surfactant(s) and nonionic surfactant(s) is preferably not less than 50% by mass, more preferably not less than 60% by mass, further more preferably not less than 70% by mass, and particularly preferably not less than 80% by mass based on the total amount (100% by mass) of all the surfactants.
[0148] Suitable examples of anionic surfactants include alkylbenzene sulfonates, alkylether sulfates, alkenylether sulfates, alkyl sulfates, alkenyl sulfates, α-olefinsulfonates, α-sulfo fatty acids and esters of these, alkane sulfonates, saturated fatty acid salts, unsaturated fatty acid salts, alkylether carboxylates, alkenylether carborylates, amino acid-type surfactants, N-acylamino acid-type surfactants, alkyl phosphates and salts of these, and alkenyl phosphates and salts of these. The alkyl groups or alkenyl groups in these anionic surfactants may be linear or branched.
[0149] Suitable examples of nonionic surfactants include polyoxyalkylene alkyl ethers, polyoxyalkylene alkenyl ethers, polyoxyethylene alkyl phenyl ethers, higher-fatty-acid alkanol amides and alkylate oxide adducts thereof, sucrose fatty acid esters, alkyl glycoxydes, fatty acid glycerin monoesters, and alkylamine oxides. The alkyl groups or the alkenyl groups in these nonionic surfactants may be linear or branched.
[0150] Suitable examples of cationic surfactants include quarternary ammonium, salts. Suitable examples of amphoteric surfactants include carboryl-type amphoteric surfactants, and sulfobetaine-type amphoteric surfactants. The alkyl groups or the alkenyl groups in these cationic and amphoteric surfactants may be linear or branched.
[0151] In these detergent compositions, those surfactants are typically present at a level of 10 to 60% by mass based on the total amount (100% by mass), and are preferably present at a level of 15 to 50% by mass, more preferably at a level of 20to 45% by mass, and further more preferably at a level of 25 to 40% by mass. The use of surfactants at a level of less than 10% by mass may result in insufficient detergency. On the other hand, the use of surfactants at a level of more than 60% by mass is disadvantageous in terms of cost.
[0152] Suitable examples of additives include stain inhibitors (e.g. benzotriazole, ethylene thiourea), soil release agents, color migration inhibitors, softening agents, alkaline substances for pH adjustment, perfumes, solubilizing agents, fluorescent agents, coloring agents, foaming agents, foam stabilizers, lustering agents, bactericides, bleaching agents, bleaching assistants, enzymes (e.g. proteases, lipases, cellulases), dyes, and solvents. Powder detergent compositions preferably contain zeolite.
[0153] These detergent compositions may contain other detergent builders in addition to the carboxyl group-containing polymer composition of the present invention. Examples of other detergent builders include, but are not particularly limited to, alkali builders such as carbonates, hydrogen carbonates, silicates, and sulfates; chelate builders such as tripolyphosphoric acid salts, pyrophosphoric acid salts, Glauber's salt, nitrilotriacetic acid salts, ethylenediaminetetraacetic acid salts, diethylenetriaminepentaacetic acid salts, citric acid salts, diglycolic acid salts, oxycarboxylic acid salts, salts of (meth)acrylic acid copolymers, acrylic acid-maleic acid copolymers, fumaric acid salts, and zeolite; and carboxyl derivatives of polysaccharides such as carboxymethyl cellulose. Examples of counter salts used with these builders include alkali metals such as sodium and potassium, ammonium, and amines.
[0154] In the detergent compositions, the above additives and other detergent builders are preferably present at a total level of 0.1 to 50% by mass based on the total amount (100% by mass). The level is more preferably 0.2 to 40% by mass, further more preferably 0.3 to 35% by mass, still further more preferably 0.4 to 30% by mass, and particularly preferably 0.5 to 20% by mass. The use of the additives and other detergent builders at a total level of less than 0.1% by mass may result in insufficient detergency, and the use of the additives and other detergent builders at a total level of more than 50% by mass is disadvantageous in terms of cost.
[0155] If should be understood that the concept of the “detergent compositions” includes detergents used only for specific usages such as bleaching detergents which have improved performance delivered by one component therein, in addition to synthetic detergents of household detergents, detergents for industrial use (e.g. detergents used in the textile industry), and hard surface detergents.
[0156] In the ease of a liquid detergent composition, the water content of the liquid detergent composition is preferably 0.1 to 75% by mass, more preferably 0.2 to 70% by mass, further more preferably 0.5 to 65% by mass, still more preferably 0.7 to 60% by mass, still further more preferably 1 to 55% by mass, and particularly preferably 1.5 to 50% by mass of the total amount of the detergent composition.
[0157] In the case of a liquid detergent composition, the kaolin turbidity of the detergent composition is preferably not more than 200 mg/L, more preferably not more than 150 mg/L, further more preferably not more than 120 mg/L, still further more preferably not more than 100 mg/L, and particularly preferably not more than 50 mg/L.
[0158] The kaolin turbidity can be measured as follows. A uniformly stirred sample (liquid detergent) is charged in a 50 mm-square cell with a thickness of 10 mm, and bubbles are removed therefrom. Then, the sample is measured for turbidity (kaolin turbidity; mg/L) at 25° C. with a turbidimeter (trade name: HDH2000, product of Nihon Denshoku Industries Co., Ltd.).
[0159] These detergent compositions have high dispersibility and are less likely to show performance deterioration even after stored for a long time, or to generate precipitation of impurities even after stored at a low temperature. Therefore, the use of these detergent compositions provides detergents with strikingly high performance and stability.
Advantageous Effects of Invention
[0160] The carboxyl group-containing polymer composition of the present invention is designed as described above and exhibits high anti-soil redeposition ability in fabric washing. Due to this performance, the carboxyl group-containing polymer composition of the present invention can be suitably used as a raw material for detergent additives and the like.
DESCRIPTION OF EMBODIMENTS
[0161] The following description is offered to describe the present invention by way of Examples. The present invention, however, is not limited only to these examples. All parts are by mass unless otherwise specified, and all percentages are by mass unless otherwise specified.
[0162] The monomers and reaction intermediates were quantified and measured for physical properties by the methods described below.
<Measurement Condition of Weight Average Molecular Weight (GPC)>
[0163] Measuring device: L-7000 series (product of Hitachi Ltd.)
[0164] Detector; HITACHI RI Detector, L-7490
[0165] Column: SHODEX Asahipak GF-310-HQ, GF-710-HQ, GF-1G 7B (products of Showa Denko K. K.)
[0166] Column temperature; 40° C.
[0167] Flow velocity: 0.5 ml/min
[0168] Calibration, curve: Polyacrylic acid standard (Product of Sowakagaku Co., Ltd)
[0169] Eluent: 0.1 N sodium acetate/acetonitrile=-3/1 (mass ratio)
<Quantification of Acrylic Acid-Based Monomer, Sulfonic Acid Group-Containing Monomer, and Hydrogen Sulfite Adduct>
[0170] The acrylic acid-based monomer, the sulfonic acid group-containing monomer, and the hydrogen sulfite adduct were quantified by liquid chromatography under the following conditions.
[0171] Measuring device; L-7000 series (product of Hitachi Ltd.)
[0172] Detector: UV detector, L-7400 (product of Hitachi Ltd.)
[0173] Column: SHODEX RSpak DE-413 (product of Showa Denko K. K.)
[0174] Temperature: 40° C.
[0175] Eluent: 0.1% phosphoric acid aqueous solution
[0176] Flow velocity: 1.0 ml/min
<Measurement of Solids Content>
[0177] A mixture of 1.0 g of a carboxyl group-containing polymer composition of the present invention and 1.0 g of water was left in an oven heated to 130° C. in nitrogen atmosphere for one hour so as to be dried. The solids content (%) and volatile component content (%) were calculated from the mass change before and after the drying step.
EXAMPLE 1
[0178] In a 1000-ml glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (29.7 g) and Mohr's salt (0.0117 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, an 80% acrylic acid aqueous solution (hereinafter, also referred to as 80% AA) (162.0 g), a 40% aqueous solution of sodium 3-allyloxy-2-hydroxypropanesulfonate (hereinafter, also referred to as 40% HAPS) (174.5 g), a 15% sodium persulfate aqueous solution (hereinafter, also referred to as 15% NaPS) (42.4 g), and a 35% sodium hydrogen sulfite aqueous solution (hereinafter, also referred to as 35% SBS) (18.2 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 35° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, 15% NaPS, and 35% SBS were 180 minutes, 120 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.
[0179] The resulting solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerizsation was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise a 48% sodium hydroxide aqueous solution (hereinafter, also referred, to as 48% NaOH (127.5 g).
[0180] Through these steps, a polymer aqueous solution (1) containing a polymer (1) of the present invention was prepared. The solids content of the polymer aqueous solution (1) was 45%, the weight average molecular weight of the polymer (1) was 30,000; and the HAPS content of the polymer aqueous solution (1) was 2000 ppm based on the solids content of the polymer aqueous solution (1).
EXAMPLE 2
[0181] In a 2000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (92.1 g) and Mohr's salt (0.0310 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (450.0 g), 40% HAPS (429.2 g), 15% NaPS (115.8 g), and 35% SBS (23.2 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, 15% NaPS, and 35% SBS were 180 minutes, 120 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.
[0182] The resulting solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (350.6 g).
[0183] Through these steps, a polymer aqueous solution (2) containing a polymer (2) of the present invention was prepared. The solids content of the polymer aqueous solution (2) was 45%; the weight average molecular weight of the polymer (2) was 39,000; and the HAPS content of the polymer aqueous solution (2) was 600 ppm based on the solids content of the polymer aqueous solution (2).
EXAMPLE 3
[0184] In a 2000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (29.1 g) and Mohr's salt (0.017 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA, (162.0 g), 40% HAPS (174.5 g), 15% NaPS (42.4 g), and 35% SBS (21.2 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, 15% NaPS, and 35% SBS were 180 minutes, 120 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.
[0185] The resulting solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (127.5 g).
[0186] Through these steps, a polymer aqueous solution (3) containing a polymer (3) of the present invention was prepared. The solids content of the polymer aqueous solution (3) was 45%; and the weight average molecular weight of the polymer (3) was 23,000; and the HAPS content of the polymer aqueous solution (3) was 1800 ppm based on the solids content of the polymer aqueous solution (3).
COMPARATIVE EXAMPLE 1
[0187] In a 1000-ml glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (31.0 g) and Mohr's salt (0.0120 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (162.0 g), 40% HAPS (174.5 g), 15% NaPS (42.4 g), and 35% SBS (30.3 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, 15% NaPS, and 35% SBS were 180 minutes, 150 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.
[0188] The resulting solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (127.5 g).
[0189] Through these steps, a comparative polymer aqueous solution (1) containing a comparative polymer (1) was prepared. The solids content of the comparative polymer aqueous solution (1) was 45%; and the weight average molecular weight of the comparative polymer (1) was 12,000.
COMPARATIVE EXAMPLE 2
[0190] In a 2000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (165.1 g) and Mohr's salt (0.0259 g) were stirred-while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (450.0 g), 40% HAPS (111.3 g), 15% NaPS (104.1 g), and 35% SBS (14.9 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, 15% NaPS, and 35% SBS were 180 minutes, 150 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.
[0191] The resulting solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (386.4 g).
[0192] Through these steps, a comparative polymer aqueous solution (2) containing a comparative polymer (2) was prepared. The solids content of the comparative polymer aqueous solution (2) was 45%; and the weight average molecular weight of the comparative polymer (2) was 40,000.
COMPARATIVE EXAMPLE 3
[0193] In a 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (79.6 g) and 40% HAPS (132.6 g) were stirred while heating to the boiling point. Thus, a polymerization reaction system was built. Next, 80% AA (198.0 g), 48% NaOH (142.6 g), 15% NaPS (48.9 g), and 35% hydrogen peroxide (hereinafter, also referred to as 35% H 2 ) 2 ) (34.9 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at the boiling point, with stirring. The drop-wise addition time of 80% AA was 180 minutes; the drop-wise addition time of 48% NaOH was 165 minutes after 15 minutes from the start of drop-wise addition of 80% AA; the drop-wise addition time of 15% NaPS was 190 minutes; and the drop-wise addition time of 35% H 2 O 2 was 140 minutes after 10 minutes from the start of drop-wise addition of 80% AA. The drop-wise addition of each solution was continuously performed at a constant rate.
[0194] The resulting solution was maintained (matured) at the boiling point for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (10.2 g).
[0195] Through these steps, a comparative polymer aqueous solution (3) containing a comparative polymer (3) was prepared. The solids content of the comparative polymer aqueous solution (3) was 45%; and the weight average molecular weight of the comparative polymer (3) was 20,000.
<Anti-Soil Redeposition Ability Test/Carbon Black>
[0196] An anti-soil redeposition ability test was performed with carbon black in the following procedure.
[0197] (1) Cotton cloth available from Testfabrics Inc. was cut into 5 cm×5 cm white cloth samples. The degree of whiteness was determined for the white cloth samples by measuring the reflectance with a colorimetric color difference meter (SE2000, product of Nippon Denshoku Industries Co., Ltd.).
[0198] (2) Pure water was added to calcium chloride dihydrate (8.82 g) such that hard water (20 kg) was prepared.
[0199] (3) A mixture (90.0 g) was prepared by adding pure water to sodium dodecylbenzensulfonate (4 g), sodium hydrogen carbonate (4.75 g), and sodium sulfate (4 g) and adjusted to pH 10 with a sodium hydroxide aqueous solution. Pure water was further added thereto such that a surfactant aqueous solution l100.0 g in total) was prepared.
[0200] (4) A tergotmeter was set at 25° C. The hard water (1 L), the surfactant aqueous solution (2.5 g), a 0.4% (cased on the solids content) polymer aqueous solution (2.5 g), zeolite (0.075 g), and carbon black (0.05 g) were stirred for one minute in a pot at 100 rpm. Subsequently, seven white cloth samples were put into the mixture, and the mixture was stirred for ten minutes at 100 rpm.
[0201] (5) The white cloth samples were wrung by hand, and hard water (1 L) at 25° C. was poured into the pot and stirred at 100rpm for two minutes.
[0202] (6) The white cloth samples were each covered with a piece of cloth and dried by ironing while wrinkles were smoothed. The cloth samples were measured again for reflectance as whiteness with the colorimetric difference meter.
[0203] (7) The anti-soil redeposition ratio was determined from the following equation, based on the measurement results. Anti-soil redeposition ratio (%)=(whiteness of white cloth after washed)/(initial whiteness of white cloth)>100
[0204] The mass ratios between the structure units (a) and (b) in the polymers, the weight average molecular weights of the polymers, the 3-sulfopropionic acid (3SPA) contents, and the anti-soil redeposition ability of the compositions prepared in Examples and Comparative Examples are shown in Table 1.
[0000]
TABLE 1
Structure units
Anti-soil
(a)/(b)
Weight average
3SPA
redeposition
(% by mass)
molecular weight
(ppm)
ability
Example 1
68/32
30,000
15,000
38.6
Example 2
70/30
39,000
4,000
37.5
Example 3
68/32
23,000
12,000
39.4
Comparative
68/32
12,000
20,000
35.5
Example 1
Comparative
90/10
40,000
300
35.9
Example 2
Comparative
77/23
20,000
0
33.5
Example 3
[0205] The results of Examples and Comparative Examples demonstrate that the carboxyl group-containing polymer compositions of the present invention which contain a carboxyl group-containing polymer including a structure unit (a) derived from an acrylic acid-based monomer (A) and a structure unit (b) derived from a sulfonic acid group-containing monomer (B) at specific levels, and having a specific weight average molecular weight, and further contain a specific amount of an adduct of a hydrogen sulfite to the acrylic acid-based monomer (A) have good anti-soil redeposition ability in hard water environment.
[0206] Thus, it is presumed that the same mechanism of sufficiently producing good anti-soil redeposition ability works when any of the compositions of the present invention having the above specific constitution.
[0207] Therefore, it should be understood from the results of Examples, the present invention can be applied in the entire technical field of the present invention and in the various modifications disclosed herein, and produce advantageous effects.
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The present invention provides a carboxyl group-containing polymer composition that exhibits excellent anti-soil redeposition ability in fabric washing. The carboxyl group-containing polymer composition contains a carboxyl group-containing polymer, which includes specific ratios of a structure unit (a) derived from an acrylic acid-based monomer (A) and a structure unit (b) derived from a sulfonic acid group-containing monomer (B) and has a specific weight average molecular weight, and a specific amount of an adduct of a hydrogen sulfite to the acrylic acid-based monomer (A).
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RELATED APPLICATION
This application is a continuation-in-part of Ser. No. 772,422, filed Sept. 4, 1985, now abandoned, and the benefits of 35 USC 120 are claimed relative to it.
BACKGROUND OF THE INVENTION
Field of the Invention and Related Art Statement
The present invention relates to a process for preparing hyaluronic acid with a microbe capable of producing hyaluronic acid (hereinafter referred to as a "hyaluronic acid-producing microbe"). More specifically, this invention relates to a process for preparing hyaluronic acid comprising incubating a hyaluronic acid-producing microbe in a culture medium containing blood serum, a bacteriolytic enzyme, a surface active agent, or a bacteriolytic enzyme plus a surface active agent to yield and accumulate hyaluronic acid in the culture medium, and isolating the same.
Hyaluronic acid exists in connective tissues such as joints, vitreous bodies, umbilical cords, cartilages, skins, and combs of fowls as a constituent thereof, and fulfils important functions such as flexibility and structure maintainence of tissues, and metabolic regulation of cells. Hyaluronic acid is a very large high molecular weight polymer, and a solution thereof has a high viscoelasticity and a water-holding function. Therefore, it has a wide variety of uses in cosmetics, medicines for wounds, eye waters, medicines for arthritis.
Hyaluronic acid has heretofore been commercially obtained by a method of extraction thereof from combs of fowls, vitreous bodies of bovine eyes, umbilical cords, cetacean cartilages, or the like. However, hyaluronic acid obtained from living bodies by the extraction method is in the form of a complex formed with a protein or a mucopolysaccharide such as chondroitin, and hence, needs complicated steps for separation and purification. Furthermore, since it is present in most cases in the form of a mixture with hyaluronidase, there has been drawbacks in that such a hyaluronic acid may be decomposed in the course of extraction and purification steps to reduce its molecular weight, and as consequent effects thereof its viscosity and water-holding property are lowered. In view of the above, an attempt to prepare hyaluronic acid by the cultivation method has been disclosed in Japanese Patent Laid-Open Specification No. 56692/1983. However, it is a difficult point of this method that the productivity of hyaluronic acid is poor.
The inventors of the present invention have made intensive investigations in order to solve the above-mentioned problem involved in the preparation of hyaluronic acid. As a result, it has been found that use of a culture medium containing blood serum added thereto or a culture medium containing a bacteriolytic enzyme and/or a surface active agent added thereto in incubation of a hyaluronic acid-producing microbe largely increases the productivity of hyaluronic acid. The present invention has been completed based on this finding.
THE OBJECT AND SUMMARY OF THE INVENTION
As is apparent from the foregoing description, the object of this invention is to provide a process for preparing hyaluronic acid with a stable and greatly increased productivity and at a low cost.
In one aspect of the present invention, there is provided a process for preparing hyaluronic acid comprising the steps of incubating a microbe capable of producing hyaluronic acid in a culture medium containing blood serum added thereto to yield and accumulate hyaluronic acid in the culture medium, and isolating hyaluronic acid therefrom.
In another aspect of the present invention, there is provided a process for preparing hyaluronic acid comprising the steps of incubating a microbe capable of producing hyaluronic acid in a culture medium containing a bacteriolytic enzyme and/or a surface active agent added thereto to yield and accumulate hyaluronic acid in the culture medium, and isolating hyaluronic acid therefrom.
DETAILED DESCRIPTION OF THE INVENTION
As the hyaluronic acid-producing microbe to be used in the process of this invention, there can be mentioned, for example, Streptococcus equi Ferm BP-879, Streptococcus zooepidemicus, Ferm BP-878.
In the process of this invention, there may be used any one of bovine blood serum, equine blood serum, swine's blood serum, caprine blood serum, sheep's blood serum, fowl's blood serum, and human blood serum. As to bovine blood serum, there may be used blood serum taken from any one of a fetus, a new-born calf, a calf, a cow, and a bull. In place of blood serum, whole blood taken from a bovine, an equine, a swine, a goat, a sheep, a fowl, or a human being may be used. Alternatively, a component differentiated from blood serum of any animal as mentioned above or a human being may be used in place of blood serum and the component fractionated from blood serum containing lysozyme. The amount of blood serum to be added to the culture medium is preferably 0.3%-5.0% by volume, most preferably 1.5% by volume.
As the bacteriolytic enzyme that may be used in the process of this invention, all bacteriolysis-active enzymes are usable, but lysozyme is most preferred. The amount of the bacteriolytic enzyme that may be added to the culture medium is not particularly limited but is preferably 100 to 2,500 units, more preferably 300 to 2,000 units, most preferably 500 to 1,000 units, per liter of the culture medium. Too small an amount of the bacteriolytic enzyme added results in a small amount of hyaluronic acid yielded and accumulated. Too large an amount of the bacteriolytic enzyme added disadvantageously leads to so much bacteriolysis that the growth of the hyaluronic acid-producing microbe may be obstructed.
As to the timing of addition of the bacteriolytic enzyme to the culture medium, it is preferred to make the addition under aseptic conditions after sterilization of a culture medium to which the enzyme is to be added, for example, according to the pressure steam sterilization method, and subsequent cooling to a temperature of 45° C. or lower.
Examples of the surface active agent that may be used in the process of this invention include cetyltrimethylammonium bromide, cetylpyridinium chloride, Tween 80 (trade name of a surfactant manufactured by Kao Kagaku Kabushiki Kaisha), Tween 90 (trade name of a surfactant manufactured by Kao Kagaku Kabushiki Kaisha), sodium laurylsulfate, Triton X-100 (trade name of a surfactant manufactured by Rohm & Haas Co.), Span 80 (trade name of a surfactant manufactured by Kao Kagaku Kabushiki Kaisha), Span 90 (trade name of a surfactant manufactured by Kao Kagaku Kabushiki Kaisha), Nonion(trade name of a surfactant manufactured by Nippon Oil and Fats Co., Ltd, and diethyhexyl sulfosuccinate. The amount of the surface active agent to be added to the culture medium is preferably 0.5 to 10 g, more preferably 0.5 to 3 g, most preferably 1.0 to 2.0 g, per liter of the culture medium. The surface active agent is added to the culture medium before sterilization of the culture medium with pressure steam.
In the process of the present invention, a culture medium before addition of the blood serum, or the bacteriolytic enzyme and/or the surface active agent may be any usually employed culture medium for incubating a hyarulonic acid-producing microbe, and may contain, for example, 2.0 to 3.0% of glucose, 0.5% of a yeast extract, 1.5% of peptone, 0.3% of potassium dihydrogenphosphate, 0.2% of potassium monohydrogenphosphate, 0.01% of sodium thiosulfate, 0.01% of magnesium sulfate heptahydrate, 0.002% of sodium sulfite, 0.001% of cobalt (II) chloride, 0.001% of manganese (II) chloride, and a 0.5% of a defoaming agent and may have a pH of, for example, 6.0 to 8.5 or 2.0% of glucose, 0.3% of potassium dihydrogen-phosphate, 0.2% of potassium monohydrogenphosphate, 0.01% of sodium thiosulfate, 0.01% of magnesium sulfate heptahydrate, 0.002% of sodium sulfite, and 0.5% of a defoaming agent and may have a pH of, for example, 6.0 to 8.5. (Every % herein and hereinafter mentioned means a weight/volume % wherein the weight and the volume are expressed in terms of gram and deciliter, respectively unless otherwise described.)
In the process for preparing hyaluronic acid according to the present invention, a culture medium containing no blood serum is sterilized, for example, according to the pressure steam sterilization method, and cooled to a temperature of 45° C. or lower, at which blood serum may be added to the above-mentioned culture medium under aseptic conditions. Subsequently, a hyaluronic acid-preparing microbe is inoculated into the resulting culture medium. The culture medium is then agitated by blowing air therethrough or allowed to stand at a temperature of preferably 25° C. to 40° C., particularly preferably 35° C., and at a controlled pH of preferably 6.5 to 8.0, most preferably about 7.0, for 1 to 2 days to effect incubation, followed by further addition of a saccharide component in an amount of 3% to the culture medium and further incubation for 10 hours to 2 days to yield and accumulate hyaluronic acid.
Alternatively, a culture medium containing neither an bacteriolytic enzyme nor a surface active agent or a culture medium containing a surface active agent and no bacteriolytic enzyme is sterilized, for example, according to the pressure steam sterilization method, and cooled to a temperature of 45° C. or lower, at which an bacteriolytic enzyme is added to the culture medium under aseptic conditions, followed by inoculation of a hyaluronic acid-producing microbe into the resulting culture medium under aseptic conditions. Where no bacteriolytic enzyme is to be added, a culture medium containing a surface active agent added thereto is sterilized, for example, according to the above-mentioned pressure steam sterilization method, and cooled to a temperature of 45° C. or lower, at which a hyaluronic acid-producing microbe is inoculated into the culture medium under aseptic conditions. The culture medium is then agitated under an air stream blowing or allowed to stand at a temperature of preferably 25° C. to 40° C., particularly preferably 30° C. to 35° C., and at a controlled pH of preferably 6.5 to 8.0, most preferably 7.0, for 1 to 2 days to effect incubation, followed by further addition of a saccharide component in an amount of 3% to the culture medium and further incubation for 1 to 2 days to yield and accumulate hyaluronic acid.
Thereafter, the culture medium is rid of the microbe by centrifugal separation or filtration, and the resulting filtrate is stripped of low molecular weight substances by ultrafiltration or dialysis. Subsequently, an alcohol such as methanol or ethanol may be added to the filtrate stripped of the low molecular weight substances to precipitate a crude product of hyaluronic acid. The precipitated hyaluronic acid is dissolved in water again. Thereafter, cetyltrimethylammonium bromide is added to the resulting solution to effect differential precipitation with the cetyltrimethylammonium bromide. Subsequently, a known purification procedure such as ion exchange chromatography or gel permeation chromatography is applied to purify the resulting hyaluronic acid.
By using a culture medium containing blood serum added thereto or a culture medium containing a bacteriolytic enzyme and/or a surface active agent added thereto according to the process of the present invention, the productivity of hyaluronic acid can be greatly improved e.g. by 4 to 5 times, per liter of the culture medium, as compared with that of the method of incubation carried out by using an ordinary culture medium containing none of blood serum, an bacteriolytic enzyme, and a surface active agent (see Comparison Examples). Furthermore, since there is almost no lot-to-lot variation in quality of the bacteriolytic enzyme and the surface active agent to be used, hyaluronic acid can be always prepared with a constant quality and productivity. Thus the present invention provides an epoch-making process for preparing hyaluronic acid. The content of the impurities in the hyaluronic acid obtained according to the process of this invention is so exceedingly small that the product of the process of the present invention is the highest grade of hyaluronic acid. Thus it can be favorably employed in applications to pharmaceuticals and cosmetics.
As has hereinbefore be described, it was confirmed that the process for preparing hyaluronic acid according to the present invention is a process capable of producing high purity hyaluronic acid in a stabilized manner with a high productivity.
The following Examples will specifically illustrate the present invention in contradictinction to Comparison Examples, but should not be construed as limiting the scope of the invention.
Streptococcus equi Ferm BP-879 and Streptococcus zooepidemicus Ferm BP 878 used in the present invention have been deposited under the Budapest Treaty and will be irrevocably and without restriction or condition released to the public upon the issuance of a patent.
EXAMPLE 1 AND COMPARISON EXAMPLE 1
22.5 ml of blood serum of a bovine new-born was added under aseptic conditions to 1.5 liters of a culture medium containing 2.0% of glucose, 0.3% of potassium dihydrogenphosphate, 0.2% of potassium monohydrogenphosphate, 0.011% of sodium thiosulfate, 0.01% of magnesium sulfate heptahydrate, 0.002% of sodium sulfite, 0.001% of cobalt (II) chloride, 0.001% of manganese (II) chloride, and 1.0% of soybean 091, and having a pH of 7.0. 100 ml of a previously prepared culture medium of Streptococcus equi Ferm BP-879 was inoculated into the resultant culture medium, and the microbe was incubated under an air stream of 0.7 vvm at a rotation of a stirrer of 300 rpm at a temeprature of 35° C. for 40 hours while automatically controlling the pH to 7.0. Thereafter, 25 g of glucose was added to the culture medium under aseptic conditions, followed by further incubation for 10 hours. 1.6 liters of ion-exchanged water was then added to the resulting culture medium, followed by centrifugal separation to remove the microbe. Dilute hydrochloric acid was added to the supernatant thus obtained to adjust the pH thereof to 5.5. The resulting solution was concentrated by a hollow-fiber ultrafilter to 0.75 liter, and dialyzed against ion-exchanged water. The resulting solution was purified by known methods; successively by differential precipitation with ethyl alcohol, treatment with cetylpyridinylammonium chloride, and chromatography with ion-exchange Cellulofine (trade mark) to obtain 8.7 g of a white powder of purified sodium Hyalurouate.
The amount of the product was 5.8 g per liter of the culture medium. The protein content of the purified sodium hyaluronate was 0.05% by weight. The molecular weight of the purified sodium hyaluronate was measured by gel permeation chromatography with Sepharose 6B (trade name) manufactured by Pharmcia Finechemicals Co., and found to be 2×10 6 daltons. A physiological saline containing 1% by weight of the sodium hyaluronate was intravenously injected to a rabbit, which, however, did not show any pyrogeneous reaction.
In a run as Comparison Example 1, a hyaluronic acid-producing microbe was incubated under the same conditions and in the same procedure as in Example 1 except that a culture medium in which serum component was removed from and 0.5% of a yeast extract and 1.5% of peptone were added to the culture medium of Example 1 was used. The resultant culture medium was subjected to the same treatment and purification as in Example 1 to obtain 0.9 g of a white powder of purified sodium hyaluronate. The amount of the product was 0.6 g per liter of the culture medium.
EXAMPLE 2
1.5 liters of a culture medium containing 2.0% of glucose, 0.5% of a yeast extract, 1.5% of peptone, 0.3% of potassium dihydrogenphosphate, 0.2% of potassium monohydrogenphosphate, 0.011% of sodium thiosulfate, 0.01% of magnesium sulfate heptahydrate, 0.002% of sodium sulfite, 0.001% of cobalt (II) chloride, 0.001% of manganese (II) chloride, and 0.5% of soybean oil, and having a pH of 7.0 was poured into a minijar fermentor having an internal volume of 3.0 liters, and sterilized with pressure steam at 120° C. for 15 minutes, followed by cooling to room temperature. 0.75 mg (675 units) of egg albumen lysozyme was added to the resultant culture medium under aseptic conditions. Subsequently, 0.1 leter of a previously prepared culture medium of Streptococcus zooepidemicus Ferm BP-878 was inoculated into the culture medium, and the microbe was incubated under an air stream of 0.7 vvm at a rotation of a stirrer of 300 rpm at 35° C. for 24 hours while automatically adjusting the pH to 7.0. Thereafter, 100 ml of a 50% aqueous glucose solution was added to the culture medium under aseptic conditions. Incubation was further continued under the above-mentioned incubation conditions for 26 hours. 3.2 liters of ion-exchanged water was added to the resultant culture medium, followed by agitation and centrifugal separation for removal of the microbe. The supernatant thus obtained was concentrated to 1.6 liters by a hollow-fiber ultrafilter, and dialyzed against ion-exchanged water. Sodium acetate was added to the resulting solution so as to give a sodium acetate content of 0.5%, followed by addition of 5 liters of ethanol for precipitation of polysaccharides including hyaluronic acid which is thereafter isolated by centrifugal separation.
The isolated polysaccharides containing hyaluronic acid was dissolved in 0.5 liter of ion-exchanged water, and 0.23 liter of a 4% of aqueous cetyltrimethylammonium bromide solution was added to the resulting solution, followed by separation of a precipitate formed. The precipitate was dispersed in 40 ml of an aqueous sodium chloride solution having a concentration of 0.3 mole/liter, followed by centrifugal separation. 120 ml of ethanol was added to the supernatant solution, followed by separation of a precipitate formed. The precipitate was dissolved in ion-exchanged water, and purified by ion exchange chromatography to obtain 7.8 g of a white powder of purified sodium hyaluronate. The amount of the product was 5.2 g per liter of the culture medium. The purified sodium hyaluronate had a protein content of 0.05% by weight. The intrinsic viscosity [η] of the purified sodium hyaluronate as measured by an Ubbellohde viscometer was 17.3 dl/g. Thus it was confirmed that the molecular weight thereof was 1,005,000 daltons.
EXAMPLE 3
1.5 liters of a culture medium containing 2.0% of glucose, 0.5% of a yeast extract, 1.5% of peptone, 0.3% of potassium dihydrogenphosphate, 0.2% of potassium monohydrogenphosphate, 0.011% of sodium thiosulfate, 0.01% of magnesium sulfate heptahydrate, 0.002% of sodium sulfite, 0.001% of cobolt (II) chloride 0.001% of manganese (II) chloride, 0.5% of soybean oil, and 1.5 g of Tween 80 (trade name) as the surface active agent, and having a pH of 7.0 was poured into a minijar fermentor having an internal volume of 3.0 liters, and sterilized with pressure steam at 120° C. for 15 minutes, followed by cooling to room temperature. Subsequently, 0.1 liter of a previously prepared culture medium of Streptococcus equi Ferm BP-879 was inoculated into the resulting culture medium under aseptic conditions, and the microbe was incubated under the same incubation conditions and by the same incubation method as in Example 2. Thereafter, the culture medium was subjected to the same purification treatment as in Example 2 to obtain 6.1 g of a white powder of sodium hyaluronate. The amount of the product was 4.1 g per 1 liter of the culture medium. The purified sodium hyaluronate had a protein content of 0.03% by weight. The intrinsic viscosity [η] thereof as measured by an Ubbellohde viscometer was 12.0 dl/g. Thus it was confirmed that the molecular weight thereof was 628,000 daltons.
EXAMPLE 4
0.7 g of Tween 80 (trade name) as the surface active agent was added to 1.5 liters of a culture medium containing 2.0% of glucose, 0.5% of a yeast extract, 1.5% of peptone, 0.3% of potassium dihydrogenphosphate, 0.2% of potassium monohydrogenphosphate, 0.011% of sodium thiosulfate, 0.01% of magnesium sulfate heptahydrate, 0.002% of sodium sulfite, 0.001% of cobolt (II) chroride, 0.00% of manganese (II) chroride, and 0.5% of soybean oil, and having a pH of 7.0. The culture medium was then poured into a minijar fermentor having an internal volume of 3.0 liters, and sterilized with pressure steam at 120° C. for 15 minutes, followed by cooling to room temperature. 0.4 mg (360 units) of egg albumen lysozyme was then added to the culture medium under aseptic condition. Subsequently, 0.1 liter of a previously prepared culture medium of Streptococcus zooepidemicus Ferm BP-878 was inoculated into the culture medium, and the microbe was incubated under the same incubation conditions and by the same incubation method as in Example 2. Thereafter, the resultant culture medium was subjected to the same purification treatment as in Example 2 to obtain 8.0 g of a white powder of purified sodium hyaluronate. The amount of the product was 5.3 g per liter of the culture medium. The purified sodium hyaluronate had a protein content of 0.04% by weight. The intrinsic viscosity [η] thereof as measured by an Ubbellohde viscometer was 15.0 dl/g. Thus it was confirmed that the molecular weight thereof was 837,000 daltons.
COMPARISON EXAMPLE 2
1.5 liters of a culture medium containing 2.0% of glucose, 0.5% of a yeast extract, 1.5% of peptone, 0.3% of potassium dihydrogenphosphate, 0.2% of potassium monohydrogenphosphate, 0.011% of sodium thiosulfate, 0.01% of magnesium sulfate heptahydrate, 0.002% of sodium sulfite, 0.001% of cobolt (II) chroride, 0.00% of manganese (II) chroride, and 0.5% of soybean oil, and having a pH of 7.0 was poured into a minijar fermentor having an internal volume of 3.0 liters, and sterilized with pressure steam at 120° C. for 15 minutes followed by cooling to room temperature. Subsequently, 0.1 liter of a previously prepared culture medium of Streptococcus zooepidemicus Ferm BP-878 was inoculated into the culture medium, and the microbe was incubated under the same incubation conditions and by the same incubation method as in Example 2. Thereafter, the culture medium was subjected to the same purification treatment as in Example 2 to obtain 1.5 g of a white powder of purified sodium hyaluronate. The amount of the product was 1.0 g per liter of the culture medium. The purified sodium hyaluronate had a protein content of 0.03% by weight. The intrinsic viscosity [η] thereof as measured by an Ubbellohde viscometer was 12.0 dl/g. Thus it was confirmed that the molecular weight thereof was 628,000 daltons.
EXAMPLES 5-7 AND COMPARATIVE EXAMPLE 3
In Example 5, to the same amount of and the same kind of the culture medium as used in Example 1, the same amount of Streptococcus equi FERM BP-879 as used in Example 1 was added and under the condition based upon Example 1, incubation was carried out for 11 hours.
In Example 6, to the same amount of and the same kind of the culture medium as used in Example 2, the same amount of Streptococcus zooepidemicus FERM BP-878 as used in Example 2 was added and under the condition based upon Example 2, incubation was carried out for 11 hours.
In Example 7, to the same amount of and the same kind of the culture medium as used in Example 3, the same amount of Streptococcus equi FERM BP-879 as used in Example 3 was added and under the condition based upon Example 3, incubation was carried out for 11 hours.
In comparative Example 3, to the same amount of and the same kind of the culture medium as used in Comparative Example 1, the same amount of Streptococcus equi FERM BP-879 as used in Comparative Example 1 was added under the condition based upon Comparative Example 1, incubation was carried out for 11 hours.
10 ml of each of the culture mediums obtained in Examples 5 to 7 and Comparative Example 3, respectively, were taken up and radia of formed capsules were measured by using an optical microscope. With regard to the remaining other culture mediums, purification treatments were carried out in Example 5 by the procedure based upon Example 1, in Example 6 by the procedure based upon Example 2, in Example 7 by the procedure based upon Example 3, in Comparative Example 3 by the procedure based upon Comparative Example 1, respectively and purified sodium hyaluronate were obtained.
The results of these experiments are shown in Table 1.
TABLE 1__________________________________________________________________________ radia (μm) production amount of of capsule number of hyaluronic acid mean standard measure- (g) per 1 L of additives value deviation ment culture medium__________________________________________________________________________Example 5 blood serum 1.88 ±0.390 26 6.0Example 6 Lysozyme 2.17 ±0.334 18 5.5Example 7 Tween 80 1.71 ±0.245 22 4.5comparative none 2.52 ±0.455 14 0.7example 3__________________________________________________________________________
When these results are subjected to test, significant differences are recognized at 99% reliability between Examples 5 or 7 and Comparative Example 3, and at 90% reliability between Example 6 and Comparative Example 3. Thus, it can be seen that the formation of capsule becomes less by the addition of blood serum, Lysozyme or Tween 80. This means that the above-mentioned additives suppress the accumulation to the hyaluronic acid capsule and performs the function of liberating hyaluronic acid to the culture medium.
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A process for producing a hyaluronic acid can be provided steadly, with a greatly improved productivity and at an inexpensive cost by incubating a hyaluronic acid-producing microbe in a culture medium formed by adding a blood serum or a bacteriolytic enzyme and/or a surfactant, accumulating and isolating the hyaluronic acid.
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BACKGROUND OF THE INVENTION
This invention relates to a capacitive sensor for determining the position of a moving element, for example, the rotor of an electromechanical actuator.
In typical capacitive sensors, for example, the one shown in Brosens, U.S. Pat. No. 4,135,119, four identical stationary curved plate electrodes are arranged around the lower end of the rotor with their inner surfaces facing the rotor. Each plate is electrically connected to the plate on the opposite side of the rotor. Thus there are two pairs of plates. The rotor has a pair of pole faces. Each pole face cooperates with two of the plates, one from each pair, such that the difference in the capacitances between the pole face and each of the two plates is a function of the rotor's angular position. In typical applications the four plates are soldered at their bases to a printed circuit board and are supported by an epoxy potting material.
It has also been proposed to form the electrode plates on two identical rings that are stacked axially (but with one rotated relative to the other). The rotor pole faces then would cooperate with the plate surfaces on the two rings to provide the desired capacitance differential.
SUMMARY OF THE INVENTION
One general feature of the invention is a capacitive position sensor in which the stationary capacitive surfaces make up two sets, one set forming a first integral unit, the other set forming a second integral unit; the two units are held together with the capacitive surfaces of each set resting in corresponding spaces in the other unit such that all surfaces of both sets intersect a common radial plane and the surfaces of one set are electrically isolated from the surfaces of the other set.
Preferred embodiments of the invention include the following features. Each integral unit is a closed ring-shaped single metal piece with the surfaces and spaces defined around its circumference. The two units are identical. Each unit includes a set of electrode plates (each bearing one of the capacitive surfaces) and a planar ring-shaped base that bridges the plates; the plates project axially from the base. An insulative board lies between and electrically insulates the respective planar bases of the two integral units. Each unit has two surfaces arranged on opposite sides of the rotating element, and the rotating element has two capacitive surfaces.
The capacitive position sensor is mechanically rigid because pairs of the plates are integrally formed and the two resulting rings are rigidly registered relative to one another. The rotor is well shielded from surfaces other than the electrode plate surfaces, minimizing stray capacitances to ground. The construction is compact and economical and is accomplished using thermally compatible materials. Null and gain drift resulting from temperature and aging are reduced; temperature stability is within the range of 100 parts per million per degree Centigrade. The assembly can be stress relieved before assembly, and no machining is required after assembly. The sensor is useful, e.g., in optical scanners.
Other advantages and features will become apparent from the following description of the preferred embodiment, and from the claims.
DESCRIPTION OF THE PREFERRED EMBODIMENT
We first briefly describe the drawings.
DRAWINGS
FIG. 1 is a cross-sectional side view of an electromechanical actuator and a schematic diagram of a feedback circuit used to drive the actuator.
FIG. 2 is a top view of the actuator.
FIG. 3 is an exploded view of the capacitive position sensor portions of the actuator.
FIG. 4 is a schematic isometric view of the capacitive sensor rings as assembled.
FIGS. 5A, 5B are top views of the capacitive position sensor with two different rotor positions.
STRUCTURE
Referring to FIGS. 1, 2, conventional actuator 10 has drive coils 12, 14 powered by a drive circuit 16 to cause rotor 18 of actuator 10 to rotate to a desired position, based on position information derived from capacitive position sensor assembly 20. The stator 15 of actuator 10 includes two stator pole pieces 17, 19 and two permanent magnets 21, 23.
Rotor 18 (50/50 nickel/iron) includes cylindrical pole faces 30, 32 (diameter 0.493 inches). Rotor 18 is mechanically grounded by a torsion bar 43. Pole faces 30, 32 cooperate with stator pole faces 34, 36, 38, 40 (on pole pieces 17, 19) to drive rotor 18 about an axis 42, supported on bearings 44, 46. The lower end of rotor 18 extends axially beyond stator pole faces 34, 36, 38, 40 and pole faces 30, 32 there provide capacitive surfaces 31, 33 that cooperate with capacitive position sensor assembly 20 to provide position information to circuit 16.
Referring to FIG. 3, the capacitive position sensor assembly 20 includes two identical integral metal rings 50, 52 (monel) each 0.250" high. These rings mate with each other through a round hole 54 in a printed circuit board 56 to form a sandwich which is mounted to a monel clamp base 58 by screws 60, 62. Clamp base 58 is fixed relative to stator 15 and provides a rear bearing seat 59 for holding the rear bearing of rotor 18. Inner capacitive surfaces 64, 66, 68, 70 of 0.055 inch thick electrode plates 72, 74, 76, 78 define a 0.500 inch diameter cylinder which surrounds rotor 18 leaving a 0.0035 inch air gap between capacitive surfaces 64, 66, 68, 70 and rotor capacitive surfaces 31, 33. The outer surfaces of electrode plates 72, 74, 76, 78 have a diameter of 0.610 inches which fits within the 0.625 inch diameter of cpening 54 in printed circuit board 56.
Thus there are two sets of capacitive sufaces: one set 64, 66 on ring 50, the other set 68, 70 on ring 52. The two surfaces of each set lie on opposide sides of the rotor.
Printed circuit board 56 includes a 0.062 inch thick printed circuit board substrate which separates rings 50, 52, keeping them electrically isolated from each other. On the top surface of board 56 is printed a copper rim 80 which is soldered to the under surface of a 0.093 inch thick lip 82 of ring 50 providing electrical contact 84 for connecting ring 20 (and hence the two capacitive surfaces 64, 66) to circuit 16 (FIG. 1). The outer diameter of rim 80 is 0.850 inches which is identical to the outer diameter of lip 82. On the bottom surface of board 56 is printed an identical copper rim (not shown) which connects to a 0.093 inch thick lip 83 of ring 52 in an identical manner.
Each ring 50, 52, includes two cutouts 81, 85, and 87, 89. Each cutout lies between two adjacent plates, and has an inner wall diameter of 0.700 inches, large enough to accommodate an electrode plate of the other ring.
Thus, referring to FIGS. 4, 5A, 5B, when assembled, the plates of each ring lie within the cutouts of the other ring with sufficient space to keep them electrically isolated from each other, and the two rings are spaced apart axially by board 56. In addition, the four capacitive surfaces 64,66, 68, 70 all intersect a common plane., e.g., the plane of board 56.
Referring again to FIG. 1, circuit 16 connects to rings 50, 52 via lines 90, 92. This circuit, which operates as described in Rohr, U.S. Pat. No. 4,142,144, assigned to the same assignee as this application, and incorporated herein by reference, produces on line 98 a current which is proportional to the difference in the capacitances to ground (note that rotor 18 is electrically grounded) of rings 50, 52. Based on this current, which is indicative of the rotor's position, position comparator 94 determines if the rotor is in the desired position, and, if necessary, adjusts the current in coils 12, 14 to correct the rotor's position.
Referring again to FIG. 3, diodes 95 mounted on board 56 are the diodes shown in the schematic of FIG. 1. Preferably the remainder of circuit 16 (FIG. 1), except for position comparator 94, is mounted on a separate printed circuit board (not shown) that is housed within the casing of actuator 10.
OPERATION
Referring to FIGS. 5A, 5B, as rotor 18 moves counter clockwise from the position in FIG. 5A to the position in FIG. 5B, the areas of pole faces 30, 32 that overlap with ring 50 increase while the areas that overlap with ring 52 decrease. Since the capacitance between a given ring and the rotor is proportional to the area of overlap, the rotor's position can be determined by computing the difference between the capacitances to ground of rings 50, 52.
Other embodiments are within the following claims.
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A capacitive position sensor for sensing changes in the position of a rotating element, in which there are two sets of stationary capacitive surfaces, one set forming a first integral unit, the other set forming a second integral unit; the two units are held together with the surfaces of each set resting in corresponding spaces in the other unit such that all surfaces of both sets intersect a common radial plane and the surfaces of one set are electrically isolated from the surfaces of the other set.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to the field of controlling a home automation system and, in particular, to controlling a home automation system by a wearable device, to regulate the user's health.
[0002] Advances in electronic technology allow for near instantaneous communication and data exchange, while leading to ever smaller devices. Recent advances in sensor technology, as well as the miniaturization of both electronics and power sources allow for the scaling down of commonly used devices. Specifically, computing devices have benefited from recent advancements in microprocessor design, providing increasingly complex computations while providing successively diminutive size.
[0003] Many smart devices provide a user with access to computing capabilities even as the user moves about to various locations. Wearable technological computing devices include non-intrusive devices a user may wear on their body without impeding daily activities. Common wearable devices may include a watch, ring, necklace, bracelet or other wrist worn device. Such devices may work independently, connect to a network, or sync to another electronic device such as a smart device similar to a mobile phone. Many wearable electronic devices include ‘smartness’ features which enables them to be programmed to operate in different modes. Such devices may have the ability to be programmed for a fixed routine and can work (start/stop/other operations) accordingly. Alternatively such devices may even be started on an occurrence of a particular event as well.
SUMMARY
[0004] According to one embodiment of the present invention, a method for controlling an appliance based on a physiological aspects of a user is provided, the method comprising: identifying, by one or more processors, a wearable device, with at least one user sensor, wherein the wearable device is associated with a user, and wherein the at least one user sensor monitors at least one physiological aspect of the user; identifying, by one or more processors, at least one controllable appliance associated with the user, with at least one appliance sensor and at least one controllable setting; receiving, by one or more processors, health information of the user; in response to receiving the health information of the user, generating, by one or more processors, a user profile, wherein the user profile comprises parameters related to the health of the user; receiving, by one or more processors, a first set of data from the wearable device and a second set of data from the at least one controllable appliance; determining, by one or more processors, whether the received first set of data and the received second set of data matches the parameters related to the health of the user; and in response to determining that the received data does not match the parameters related to the health of the user, adjusting, by one or more processors, at least one controllable setting of the at least one controllable appliance, so that the second set of data from the at least one controllable appliance and the first set of data from the wearable device matches the user profile.
[0005] Another embodiment of the present invention provides a computer program product for controlling an appliance based on a physiological aspects of a user, based on the method described above.
[0006] Another embodiment of the present invention provides a computer system for controlling an appliance based on a physiological aspects of a user, based on the method described above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a functional block diagram illustrating a data processing environment, in accordance with an embodiment of the present invention;
[0008] FIG. 2A is a flowchart illustrating the operational steps for coordinating appliance profiles, in accordance with an embodiment of the present invention;
[0009] FIG. 2B is a flowchart illustrating operational steps for controlling a user's environment, in accordance with an embodiment of the present invention;
[0010] FIG. 3 is a block diagram depicting communication between components of FIG. 1 , in accordance with an embodiment of the present invention; and
[0011] FIG. 4 is a block diagram of the internal and external components of a computer system, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
[0012] Electronic devices have become an essential part of daily life. The small size of computing devices allows them to be easily portable and even wearable. Wearable devices, are unobtrusive for the wearer, as they are small and light weight.
[0013] Advances in electronic technology allow for devices to communicate and exchange data. Many devices have ‘smartness’ features enabling such devices to be programmed to operate in different modes. For example, devices may be programmed for a fixed routine providing various operations (i.e., start, stop, etc.). For instance, at a predetermined time, powering on an air conditioner and/or heater, to make the environment comfortable when the user arrives. Similarly, in another instance, at a predetermined time, powering on an oven (with food already in it), such that a meal will be ready when the user returns home from a day at work. Such devices may even be started on an occurrence of a particular event. For instance, a water pump may engage and fill a water tank on sensing a low water level.
[0014] With wide spread of the Internet of things (TOT), there is an emergence of new abilities to control consumer devices using applications that are installed on smart devices (referred to hereinafter as ‘App’). The IOT is the network of physical objects (devices) containing electronic sensors, software and network connectivity, which enable the physical objects to collect and exchange data with other physical devices and/or electronic systems. The IOT, through a network infrastructure, allows objects to be sensed and controlled remotely, integrating physical objects with electronic computer systems.
[0015] In an exemplary embodiment of the present invention, IOT may be used to monitor and control various mechanical and electrical systems used in one's home. For example, IOT may be used to improve a person's personal comfort, convenience, and security by controlling lighting, heating, ventilation, air conditioning, appliances, communication systems, and home security systems. For instance, utilizing a device's tracking information, such as location of a user, an App may help automatically activate one or more consumer devices at home on meeting pre-determined criteria.
[0016] Embodiments of the present invention provide systems and methods to automatically utilize a wearable device by receiving and analyzing inputs for various user parameters activities, and then accordingly controls/programs the TOT enabled appliances used by the user to ensure that the health profile of the user is maintained. Additionally, embodiments of the present invention provide systems and methods to automatically control the TOT if the user's normal routine is altered in order to improve the user's personal comfort, and/or physiological health.
[0017] Embodiments of the present invention derive different user activities that directly and/or indirectly relate with the health of the user, and through TOT influence the functioning of smart appliances to benefit the user's health. The user's health may be determined from the body temperature of the user.
[0018] It is to be understood that while the concepts included herein are presented in the context of a wearable device, the concepts disclosed herein may be applied in other contexts as well if the appropriate hardware is available.
[0019] The present invention will now be described in detail with reference to the Figures. FIG. 1 is a functional block diagram illustrating a data processing environment, in accordance with an embodiment of the present invention. FIG. 1 provides only an illustration of one embodiment and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environment may be made by those skilled in the art without departing from the scope of the invention, as recited by the claims.
[0020] In the depicted embodiment, environment 100 includes server 120 , smart appliance 130 , wearable device 140 , all interconnected over network 110 . Server 120 , smart appliance 130 and wearable device 140 may include internal and external hardware components, as depicted and described in further detail with respect to FIG. 4 .
[0021] Network 110 may be a local area network (LAN), a wide area network (WAN), such as the Internet, the public switched telephone network (PSTN), a mobile data network (e.g., wireless Internet provided by a third or fourth generation of mobile phone mobile communication), a private branch exchange (PBX), any combination thereof, or any combination of connections and protocols that will support communications between server 120 , smart appliance 130 , and wearable device 140 , in accordance with embodiments of the invention. Network 110 may include wired, wireless or fiber optic connections. Environment 100 may include additional computing devices, servers or other devices not shown.
[0022] In the exemplary embodiment, server 120 is a server computer. In other embodiments, server 120 may be a management server, a web server or any other electronic device capable of receiving and sending data. In another embodiment, server 120 may represent a server computing system utilizing multiple computers as a server system, such as in a cloud computing environment. Server 120 contains dynamic user program 122 , and information repository 124 .
[0023] In the various embodiments of the present invention, dynamic user program 122 receives various data, for example geographical and physiological of a user, and determines how to improve the user's personal comfort, and/or physiological health corresponding to the detected received data.
[0024] Dynamic user program 122 may track geological locations and physiological conditions of the user via sensor(s) 142 in wearable device 140 . Dynamic user program 122 operates generally to control smart appliance 130 based on a user's geological location and physiological condition. Dynamic user program 122 analyzes all information contained in information repository 124 relating to a specific user's wearable device 140 . While depicted on server 120 , in the exemplary embodiment, dynamic user program 122 may be located on wearable device 140 , maintaining and managing smart appliances 130 .
[0025] In an embodiment dynamic user program 122 receives various data, for example geographical and physiological of a user. Dynamic user program 122 may analyze data received from sensor(s) 132 and sensor(s) 142 .
[0026] Dynamic user program 122 may analyze data received from additional sensor(s) not show in environment 100 . Dynamic user program 122 , may for example intelligently track numerous aspects of a user based on information received from sensor(s) 142 . Utilizing at least one sensor(s) 142 , the wearable program may detect various geographical and physiological aspects of a user, which correlate to specific predetermined activity.
[0027] For example, dynamic user program 122 may detect a routinely occurring activity pattern for a specific day, date and/or time. Thereby if the user breaks from his regular routine, dynamic user program 122 will automatically adjust smart appliance 130 accordingly.
[0028] In another example, dynamic user program 122 may detect a spike in a user's physiological condition, and automatically adjust smart appliance 130 to assist the user accordingly. For example, if a user's heartrate and temperate rise, dynamic user program 122 may determine a user is working out and automatically adjust the thermostat at the user's house to best suit the user. In another example, sensors determine that the user is sleeping, dynamic user program 122 may derive a specific meal to eat when the user wakes up conforming to the user's health profile as provided by a dietitian.
[0029] Dynamic user program 122 may include a user interface allowing a user to interact with the program and set baseline parameters. The user interface may be a graphical user interface. For example, the graphical user interface may include a dashboard to view a listing of all registered smart appliances, ability to remove a smart appliance, ability to add a new smart appliance as well as details of the user's physiological parameters.
[0030] Information repository 124 may include any suitable volatile or non-volatile computer readable storage media, and may include random access memory (RAM) and cache memory (not depicted in FIG. 1 ). Dynamic user program 122 may be stored in a persistent storage component (not depicted) for execution and/or access by one or more of processor(s) via one or more memories (for more detail refer to FIG. 4 ). Alternatively, or in addition to a magnetic hard disk drive, the persistent storage component can include a solid state hard drive, a semiconductor storage device, read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, or any other computer readable storage media that is capable of storing program instructions or digital information.
[0031] Information repository 124 can be implemented using any architecture known in the art such as, for example, a relational database, an object-oriented database, and/or one or more tables. Information repository 124 stores actual, modeled, predicted, or otherwise derived patterns of movement based on sensor data. For example, information repository 124 stores all information received from wearable device 140 . Information repository 124 may contain lookup tables, databases, charts, graphs, functions, equations, and the like that dynamic user program 122 may access to both maintain a specific parameter as well as manipulate various parameters on smart appliance 130 . Information stored in information repository 124 may include: various geographical locations, specific physiological actions linked to the various geographical locations, various user patterns, and the like. While depicted on server 120 , in the exemplary embodiment, information repository 124 may be on a remote server or a “cloud” of computers interconnected by one or more networks utilizing clustered computers and components to act as a single pool of seamless resources, accessible to dynamic user program 122 via network 110 .
[0032] In the various embodiments of the present invention, smart appliance 130 represents any physical object of the IOT which may be controlled to affect the physiological wellbeing of a user, and/or to increase the overall environment efficiency by minimizing wasted electricity. It is noted that although FIG. 1 depicts only one smart appliance 130 , there can be numerous smart appliances receiving commands from dynamic user program 122 . For example, smart appliance 130 many include a user's oven, car, smart phone, smart TV, heating air conditioning and ventilation (HVAC) equipment, etc.
[0033] Smart appliance 130 is controlled by dynamic user program 122 . In the various embodiments of the present invention, smart appliance 130 may represents an air conditioning unit, a heating unit, a ventilation system, cooking equipment or any other type of object associated with the IOT. Smart appliance 130 includes sensor(s) 132 .
[0034] Sensor(s) 132 detect and/or measure various environmental aspects in or around smart appliance 130 . Utilizing the IOT, sensor(s) 132 detects aspects of the physical world, and integrates such measurements into the electronic system. In an embodiment of the present invention, sensor(s) 132 may detect the ambient temperature of smart appliance 130 , and transmit such information to dynamic user program 122 . For example, if dynamic user program 122 determines that the temperature of a user's house needs be at a specific level in order to maintain the user's ideal physiological temperature, then through sensor(s) 132 , dynamic user program 122 will know either to change (raise or lower the temperature) or maintain the current temperature of smart appliance 130 .
[0035] Smart appliance 130 allows for automatic customization by dynamic user program 122 . For example, smart appliance 130 may be controlled via a thermostatic control interface for an air conditioning or heating unit, wherein dynamic user program 122 can raise or lower the environmental temperature based on the user's determined geographical and/or physiological need. In another example, smart appliance 130 may be controlled via thermostatic control interface for an oven, wherein dynamic user program 122 can raise the oven temperature based on the user's determined geographical and/or physiological need.
[0036] In the various embodiments of the present invention, wearable device 140 represents wearable devices. For example, wearable device 140 might be smart watches, capable of detecting various inputs and transmitting data to server 120 . Wearable device 140 may be multi-purpose devices that, for example, include a telephone, or digital music player, a fitness tracker, a ring, etc. Examples of wearable device 140 include, but are not limited to, a ring, a bracelet, a wristband or a wristwatch. Generally, wearable device 140 is wearable and able to detect various geographical and physiological aspects of the user. In an exemplary embodiment, wearable device 140 is a device worn by a user. Wearable device 140 includes sensors(s) 142 .
[0037] Wearable device 140 may be provided in various form factors and may be designed to be worn in a variety of ways. In some embodiments of the present invention, a wearable device 140 is a smart watch. A smart watch is a computerized wristwatch with functionality that is enhanced beyond mere time keeping; rather a smart watch is essentially a wearable computer. Many smart watches can run applications, while others contain additional capabilities, for example, making and receiving phone calls, replacing a traditional smart phone. In other embodiments of the present invention, a wearable device 140 is a wrist band.
[0038] In an embodiment, wearable device may include a user interface (not show), allowing the user to override, if necessary, dynamic user program 122 . A user interface may include a graphical user interface.
[0039] Sensor(s) 142 sense, detect and/or measure various movements and physiological conditions of a user. For example, sensor(s) 142 might detect motion of the user, via accelerometers, gyroscopes etc. Similarly, sensor(s) 142 may include access to a global positioning system (GPS) allowing dynamic user program 122 to determine the exact location and speed of travel of the user. Additionally, sensor(s) 142 may detect physiological aspects of the user such as body temperature, heart rate, blood pressure, and the like. Sensor(s) 142 may be any sensor or sensor system known in the art to assist dynamic user program 122 in determining aspects of the user, in order ensure the health of the user.
[0040] One of ordinary skill in the art will appreciate that any arrangement of input sensors may be included on wearable device 140 to receive data of the user. Sensors 142 of wearable device 140 may include, but are not limited to, accelerometers, gyroscope, thermometer, altimeter, barometer, compass, location determining device (e.g., GPS), proximity sensors, motion detectors, touch sensors, or the like. As one skilled in the art may see, any sensor or sensor combination in wearable device 140 may be used without deviating from the invention, as sensor(s) 142 permit a user to interact with wearable device 140 .
[0041] Wearable device 140 may include an information repository as well as additional components not shown.
[0042] In an embodiment, wearable device 140 may leverage other devices external to the wearable device such as a mobile phone or a personal computer. For example, wearable device 140 may access a user's smart TV to determine how much television the user watched and recommend low calorie food as the user may have been inactive for a period of time.
[0043] The concepts disclosed and discussed herein, may be applied to both, a standalone wearable device (similar to that of wearable device 140 ), as well as a wearable device that leverages functionalities provided in external devices, e.g., smartphones, wireless headphones, etc.
[0044] Reference is now made to FIG. 2A and FIG. 2B . FIG. 2A is flowchart 200 A illustrating operational steps for coordinating appliance profiles, in accordance with an embodiment of the present invention. FIG. 2B is flowchart 200 B illustrating operational steps for controlling a user's environment, in accordance with an embodiment of the present invention.
[0045] Flowchart 200 A depicts dynamic user program 122 acquisition of information and determining an appropriate user profile. In step 210 , dynamic user program 122 , detects a wearable device, similar to that of wearable device 140 , of FIG. 1 . In an embodiment, a wearable device may be capable of detecting various user parameters such as one's physical conditions. Similarly, in an embodiment, the detected wearable device may detect and/or determine a user's activity level. For example, the detected wearable device providing physiological conditions on the user may provide details such as, the sleep the user had, the kind of working the user had completed, the type of workout completed, users current body temperature and the like. In an embodiment wearable device may sense the user's surroundings, such as temperature, barometric pressure, humidity level etc. An embodiment of the present invention may also notate the time of each sensor reading.
[0046] Wearable device 140 may keep track of the user's physiological conditions. Alternatively, an information repository associated with wearable device or dynamic user program 122 may keep track of the user's physiological conditions. A user's physiological conditions may include workout duration, workout intensity, calorie count, sleep duration, body temperate, daily routine, etc.
[0047] In step 212 dynamic user program 122 receives at least one controllable smart appliance, similarly to that of smart appliance 130 of FIG. 1 . In an embodiment, smart appliance 130 has an ability to communicate with dynamic user program 122 . In an embodiment, smart appliance 130 may be registered and/or controlled by dynamic user program 122 . In an embodiment smart appliance 130 may be controlled directly from wearable device 140 .
[0048] Optionally in step 212 , dynamic user program 122 may receive a health profile of a user. In an embodiment, dynamic user program 122 may receive a health profile as created by a user's doctor, dietitian, family member, or any other individual who has knowledge of the user and can assist the user in creating a health profile. Alternatively, or additionally, dynamic user program 122 may generate the health profile of the user by prompting the user with multiple questions and physiological readings in order to create a baseline of the user.
[0049] In step 214 , dynamic user program 122 , generates a profile for the appliances based on the user's health profile (as received in step 220 ). In an embodiment, dynamic user program 122 , may utilize various readings from smart appliance 130 and will determine IOT appliance settings that comply with the health profile of the user. Based on the generated profile of appliances, dynamic user program 122 , may, based on the immediate health needs of the user, automatically alter the smart appliances.
[0050] Flowchart 200 B depicts dynamic user program 122 acquiring of information from sensors and determining an appropriate environment for the user. In step 210 , dynamic user program 122 , receives information from a user's wearable device 140 and/or from a smart appliance 130 registered to a user's wearable device 140 . Received information may relate to any physiological condition of the user as sensed by a sensor 142 on wearable device 140 .
[0051] In step 224 , dynamic user program 122 , analyzes the data and determines whether the environment corresponds to the user health profile as generated in step 214 . Based on the physiological conditions and the respective attributes obtained by wearable device 140 for a user, dynamic user program 122 , manages all the registered consumer smart devices and automatically adjusts each device to be best suited for the user. If in step 224 it is determined that the environment is within the parameters set within the user health profile, then dynamic user program 122 , returns to step 220 waiting to receive new data on the user.
[0052] However, if the environment does not correspond to the user health profile, then in step 226 , dynamic user program 122 adjusts the environment by controlling one or more smart devices. Dynamic user program 122 achieves automatic customization of the user's appliances as the program dynamically adapts following the user's physiological attributes obtained from the user's wearable device. In an embodiment, dynamic user program 122 , ensures no adverse impact on the user's health. In an embodiment, dynamic user program 122 , optimizes the usage of the consumer appliances, as they are utilized only when necessary as they adapt specifically to the user.
[0053] In an embodiment, based on the received readings in step 220 , dynamic user program 122 will inform the smart appliances about the required settings that comply with the user health profile of the user. Thereby the smart appliance will adjust to meet the health needs of the user.
[0054] Reference is now made to FIG. 3 . FIG. 3 is a block diagram depicting communication between components of FIG. 1 , in accordance with an embodiment of the present invention. Embodiment 300 portrays the communication between three components, wearable device 140 , dynamic user program 122 , and smart appliance 130 . It is noted that embodiment 300 may contain additional components not shown, for example, there can be more than one smart appliance.
[0055] Line 310 represents wearable device 140 ′s continuous monitor of a user's physiological attributes. Line 310 also represents syncing and communicating the user's physiological attributes to dynamic user program 122 .
[0056] Line 320 represents the syncing of smart appliances 130 current state to dynamic user program 122 . Smart appliance 130 sends current environmental status updates to dynamic user program 122 . In return for a status update coupled with the user's physiological condition, line, 325 represents dynamic user program 122 automatic customization of smart appliances 130 , based on wearable data.
[0057] In an exemplary embodiment, dynamic user program 122 oversees and prevents health issues if a user's schedule changes. For instance, if an individual is in a hot environment, and suddenly switches to a cold environment, then the individual may face health issues such as, an asthma attack or dry skin. For example, dynamic user program 122 detects, from wearable device 140 , that the user is working out and in a warm environment and dynamic user program 122 detects, from the user's smart air conditioning appliance, that the user's house is set to cool; then dynamic user program 122 may override the preset temperature of the smart air conditioning unit and fine tune the actual temperature to meet the physiological needs of the user. Further, if dynamic user program 122 determines the user is 20 minutes away from the house and it takes 13 minutes to bring the temperature of the house to the ideal setting, then dynamic user program 122 , may engage the air conditioning 7 minutes after the determination, to most effectively and efficiently use electricity in conjunction to benefiting the user's health.
[0058] Similarly, dynamic user program 122 , may even preset the user's water temperature in the shower to align with the user's physiological conditions, in particular the user's body temperature.
[0059] In an exemplary embodiment, dynamic user program 122 , may override a predefined smart appliance schedule due to a change in the user's schedule. For example, if the user has a daily routine of waking up in the morning, placing a high caloric dinner in the microwave oven to eat after work, going to the gym, then work, then on his way home from work at a certain predefined distance, the microwave oven automatically turns on, cooking his meal so it is ready when the user arrives at home following his day at work. However, if the user's routine changed as the user skipped the gym, then the user would need to alter the predefined program set for the microwave oven, as the food may not be recommended if the user did not work out. Therefore, dynamic user program 122 detects, from wearable device 140 , that the user did not work out today, breaking from the normal pattern. Therefore, dynamic user program 122 determines that the user should not eat a high caloric dinner, and will interrupt the predefined program for the microwave oven.
[0060] In this exemplary embodiment, dynamic user program 122 , may assist the user in determining what to eat based on current physiological conditions. For example, if a dietitian provided the user with a diet App to help the user order food, dynamic user program 122 may recommend specific food based on whether the user received less sleep, partook in an unplanned activity, or exhibited measurable signs of stress.
[0061] FIG. 4 is a block diagram of internal and external components of a computer system 400 , which is representative of the computer systems of FIG. 1 , in accordance with an embodiment of the present invention. It should be appreciated that FIG. 4 provides only an illustration of one implementation, and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environment may be made.
[0062] Computer system 400 includes communications fabric 402 , which provides communications between computer processor(s) 404 , memory 406 , persistent storage 408 , communications unit 412 , and input/output (I/O) interface(s) 414 . Communications fabric 402 can be implemented with any architecture designed for passing data and/or control information between processors (such as microprocessors, communications and network processors, etc.), system memory, peripheral devices, and any other hardware components within a system. For example, communications fabric 402 can be implemented with one or more buses.
[0063] Memory 406 and persistent storage 408 are computer readable storage media. In this embodiment, memory 406 includes random access memory (RAM) 416 and cache memory 418 . In general, memory 406 can include any suitable volatile or non-volatile computer readable storage media.
[0064] Persistent storage 408 may include, for example, a plurality of magnetic hard disk drives. Programs are stored in persistent storage 408 for execution and/or access by one or more of the respective computer processors 404 via one or more memories of memory 406 . In this embodiment, persistent storage 408 includes a magnetic hard disk drive. Alternatively, or in addition to a magnetic hard disk drive, persistent storage 408 can include a solid state hard drive, a semiconductor storage device, read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, or any other computer readable storage media that is capable of storing program instructions or digital information.
[0065] The media used by persistent storage 408 may also be removable. For example, a removable hard drive may be used for persistent storage 408 . Other examples include optical and magnetic disks, thumb drives, and smart cards that are inserted into a drive for transfer onto another computer readable storage medium that is also part of persistent storage 408 .
[0066] Communications unit 412 , in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit 412 includes one or more network interface cards. Communications unit 412 may provide communications through the use of either or both physical and wireless communications links. Software and data used to practice embodiments of the present invention can be downloaded to computer system 400 through communications unit 412 (i.e., via the Internet, a local area network, or other wide area network). From communications unit 412 , the software and data may be loaded to persistent storage 408 .
[0067] I/O interface(s) 414 allows for input and output of data with other devices that may be connected to computer system 400 . For example, I/O interface 414 may provide a connection to external devices 420 , such as a keyboard, keypad, a touch screen, and/or some other suitable input device. External devices 420 can also include portable computer readable storage media such as, for example, thumb drives, portable optical or magnetic disks, and memory cards. Software and data used to practice embodiments of the present invention, can be stored on such portable computer readable storage media and can be loaded onto persistent storage 408 via I/O interface(s) 414 . I/O interface(s) 414 also connect to a display 422 .
[0068] Display 422 provides a mechanism to display data to a user and may be, for example, a computer monitor. Display 422 can also be an incorporated display and may function as a touch screen, such as a built-in display of a tablet computer.
[0069] The present invention may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention.
[0070] The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.
[0071] Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device.
[0072] Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention.
[0073] Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions.
[0074] These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks.
[0075] The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks.
[0076] The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.
[0077] The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The terminology used herein was chosen to best explain the principles of the embodiment, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
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Embodiments of the present invention provide a method and system for dynamically controlling an appliance based on information received from a wearable device, to regulate the user's health. A wearable device is identified and configured to monitor at least one physiological aspect of the user. A controllable appliance with at least one sensor and at least one controllable setting is also identified. Health information of the user is received and utilized in generating, a user profile which comprises parameters related to the health of the user. Data from the wearable device and data from the controllable appliance is analyzed and it is determined whether the data matches the parameters related to the health of the user. If the data does not match the parameters related to the health of the user, then at least one controllable setting of the at least one controllable appliance is adjusted.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not applicable.
BACKGROUND
[0002] 1. Field of Invention
[0003] This invention relates to flexible band retainers; specifically, a means to keep electrical cords coiled or bundled up, and a means to secure male to female connections.
[0004] 2. Description of Prior Art
[0005] In the past, attempts have been made to provide a means to keep or secure coiled or bundled electrical cord. U.S. Pat. No. 5,802,676 discloses a strap, which secures a bundled cord using hook latch material. However, this fastener is rendered ineffectual when it collects dirt and debris. U.S. Pat. No. 5,024,402 to Hamel, another strap type device, is for use exclusively on small tools and appliances. U.S. Pat. No. 4,182,005 reveals another strap type cord keeper with a cumbersome mechanism to cinch up the strap. A need has long existed to provide a simple cord keeper.
[0006] A need has also existed for a means to keep secure the connection of male to female plug ends on electrical cords. Many contemporary patents that address this problem suffer from deficiencies and disadvantages. A keeper should have high retentive properties without requiring excessive accuracy of location. Some keepers heretofore known are very complicated for such a simple task. Many of these could cause damage to the electrical cord resulting in electrical short. A keeper should be made of nonconductive material as to be effectively insulated electrically.
[0007] Examples of contemporary keepers which present some of the above mentioned problems are disclosed in U.S. Pat. Nos. 4,690,476; 5,104,335; and 5,732,445.
SUMMARY OF INVENTION
[0008] In accordance with the present invention a cord keeper strap comprises a strap with elastic properties, a plurality of holes along the longitudinal axis thereof, and a button fastener.
OBJECTS AND ADVANTAGES
[0009] Accordingly, several objects and advantages of the present invention:
[0010] (a) to provide a simpler keeper that can be easily attached to a single strand of electrical cord;
[0011] (b) to provide a keeper that by means of its resilient elastic character can be stretched around bundled or coiled strands of electrical cord, rope, hoses or the like, thereby securing said article for storage;
[0012] (c) to provide a keeper which can be used to secure the connection between male and female plug ends on electrical cords;
[0013] (d) to provide a keeper suitable for securing unwanted slack in electrical cords on household appliances, and;
[0014] (e) to provide a keeper suitable for securing the bundled cord of a small tool or appliance to said article.
DRAWING FIGURES
[0015] In the drawings a closely related figure has the same number and an alphabetic suffix.
[0016] [0016]FIG. 1 is a plan view of a cord keeper strap.
[0017] [0017]FIG. 2 is a side elevation view of a button fastener.
[0018] [0018]FIG. 2A is a plan view of a button fastener.
[0019] [0019]FIG. 3 is a perspective view showing a cord keeper strap attached to a typical electrical cord.
[0020] [0020]FIG. 4 is a perspective view showing a cord keeper strap in a typical application securing a coiled electrical cord.
[0021] [0021]FIG. 5 is a perspective view of a cord keeper strap securing the male to female connection of electrical cords.
[0022] [0022]FIG. 6 is a perspective view of a cord keeper strap securing a bundled electrical cord.
[0023] [0023]FIG. 7 is a perspective view of a cord keeper strap securing a bundled cord to a tool.
REFERENCE NUMERALS IN DRAWINGS
[0024] [0024] 10 cord keeper strap 12 round hole 14 cross shaped hole 16 slotted hole 18 billet end of strap 20 head of button fastener 22 circular flange 24 base of button fastener 26 shank of button fastener 28 electrical cord 32 male electrical cord plug 34 female electrical cord plug 36 tool (drill motor)
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0025] A preferred embodiment of the present invention the cord keeper strap is illustrated in FIG. 1. The strap 8 is composed of a flexible and elastic material, preferably, fabricated from a suitable grade of rubber or plastic, to achieve the desired elasticity. The strap 8 has a plurality of holes aligned along the longitudinal axis. Round hole 12 is designed to accept the button fastener as illustrated in FIG. 2. Head 20 and shank 26 can be forcibly inserted through hole 12 by means of the strap material surrounding the hole yielding to the thrust of insertion. The base 24 comes to rest against said strap while circular flange 22 is seated in hole 12 . The diameter of circular flange 22 is slightly greater than the diameter of hole 12 to ensure a proper seating abutment.
[0026] As illustrated in FIG. 3, while base 24 rests against cord 28 , cross shaped hole end of strap is wound part way around cord 28 . Billet end 18 is passed through cross shaped hole 14 thus encircling cord 28 . Furthermore, since the composition of the strap is substantially elastic, flexible and resilient, by stretching and pulling a tight cincture can be made about cord 28 .
[0027] As illustrated in FIG. 4, once a cincture has been made and strap 10 is attached to cord 28 , the remainder of strap 10 can be stretchably wrapped around the whole of coiled cord 28 . After wrapping cord 10 one or more times around said coiled cord 28 , select an appropriate slotted hole 16 as to provide a tight cincture, and pull said hole over head 20 . Allow the elastic properties of the strap to pull the slotted or narrower end of hole 16 against shank 26 completing a cincture and securing cord 28 for stowage.
[0028] [0028]FIG. 5 illustrates another application of the present invention. While strap 10 is already affixed to the male end 32 of an electrical cord, and the male end 32 to female end 34 connection is made with another cord, it is desirable to keep that connection secure. Strap 10 can be stretchably wrapped around and over female plug end 34 and accompanying cord 28 one or more times, configuration is determined by the size and shape of said plug ends 32 and 34 . Select an appropriate hole 16 and by pulling it over button head 20 , as described above, said male to female connection will be held secure.
[0029] [0029]FIG. 6 illustrates another embodiment of the present invention. The cord keeper strap can be wholly smaller yet proportionately the same. In this embodiment the base 24 and flange 22 may be molded as part of strap 10 leaving only shank 26 and head 20 outwardly exposed. In this application a bundled electrical cord 28 can be secured by using the same method as described for FIG. 4. Since cincture to any electrical cord is not restricted by excessive accuracy of location the same method of securing can be used on a bundle of slack anywhere on the length of said electrical cord.
[0030] [0030]FIG. 7 illustrates another application of the present invention. A bundled electrical cord 28 with affixed cord keeper strap 10 can be secured to its host tool 36 or small appliance. While holding said bundled cord 28 against a suitable part of tool 36 , the strap 10 is stretchably wrapped around both cord 28 and the suitable part of tool 36 . Select a proper hole 16 and pull it over button head 20 . The tool and cord are now ready for storage.
[0031] In view of the forgoing, it can be seen that the present invention provides an improved cord keeper. By means of its resilient elastic character the cord keeper strap is an effective and useful tool for securing electrical cords and like articles in many applications.
[0032] While particular embodiments of the present invention have been shown and described some changes and modifications may be made without departing from the broader aspects of the present invention. Therefore, it is the aim of the appended claims to cover all such embodiments.
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A cord keeper strap is disclosed herein having an elongated flexible strap with resilient elastic properties and a plurality of holes along its longitudinal axis. Through employment of a selected hole a cincture can be made about a cord. Other selected holes may be employed by a button fastener and to secure bundled or coiled articles for storage.
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REFERENCE TO RELATED APPLICATIONS
[0001] This application is a national stage application under 35 USC 371 of International Application No. PCT/JP2009/065043, filed Aug. 28, 2009, which claims priority from Japanese Patent Application No. 2008-222075, filed Aug. 29, 2008, the contents of which prior applications are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a semiconductor light emitting element which is resistant to an open failure, and a semiconductor light emitting device using the semiconductor light emitting element.
BACKGROUND OF THE INVENTION
[0003] A semiconductor light emitting element using nitride semiconductors such as gallium nitride is capable of emitting an ultraviolet light, a blue light, a green light and the like and has a high light emitting efficiency and property of low power consumption, as well as the semiconductor light emitting element is easy to reduce a size, resistant to, for example, mechanical vibrations and has a long life and high reliability. Therefore, applications of the semiconductor light emitting element to a large scale display, a traffic light, a backlight of a liquid crystal display and the like have rapidly progressed, recently.
[0004] The semiconductor light emitting element generally has a stack structure provided with a light emitting layer between a n-type semiconductor layer and a p-type semiconductor layer and emits a light by recombination of an electron and a hole injected into the light emitting layer from the n-type semiconductor layer and the p-type semiconductor layer, respectively. Therefore, a technology of how to efficiently extract the light generated in the light emitting layer is the important technology that determines a characteristic (efficiency) of the light emitting device.
[0005] Hence, a semiconductor light emitting element having a structure provided with an n-type semiconductor layer, an n-side pad electrode disposed on a part of the n-type semiconductor layer, a light emitting layer widely disposed on the n-type semiconductor layer so as to separate from the n-side pad electrode, a p-type semiconductor layer disposed on the light emitting layer, an insulator layer disposed on a part of the p-type semiconductor layer, a transparent electro de layer covering an exposed surface of the p-type semiconductor layer and the insulator layer, and a p-side pad electrode disposed at a position facing the insulator layer across the transparent electrode layer has been known (see, for example, Patent Documents 1 to 5).
[0006] The n-side pad electrode and the p-side pad electrode are connected to an external circuit (power source), respectively by wire bonding or bump bonding in order to apply a voltage between the n-type semiconductor layer and the p-type semiconductor layer. In the semiconductor light emitting element described above, a light emission just below the p-side pad electrode can be suppressed, and a light toward the p-side pad electrode from the light emitting layer is reflected to a side of a light emitting surface (a contact surface between the transparent electrode layer and the p-type semiconductor layer) by the insulator layer to be output from the light emitting surface. As a result, a high light emitting power can be obtained.
[0007] In addition, as an another example, a structure has been proposed, in which an electrode layer having a high contact resistance or a semiconductor layer having a low electrical conductivity is disposed on the p-type semiconductor layer, and the p-side pad electrode is disposed on the electrode layer, while contacting with a transparent electrode layer (see, for example, Patent Documents 6 to 8). In the structure, a light emission just below the p-side pad electrode is suppressed, thereby resulting in high light emitting power.
[0008] However, in the semiconductor light emitting elements disclosed in the Patent Documents 1 to 5 and the Patent Documents 6 to 8, there is a common problem that a disconnection in the transparent electrode layer is likely to be caused. Explanation will be given of the problem in reference to FIG. 8A and FIG. 8B . FIG. 8A is a cross sectional view schematically showing a structure in the vicinity of the p-side pad electrode in a conventional semiconductor light emitting element. As shown in FIG. 8A , a semiconductor light emitting element 110 A has a structure in which an insulator layer, or an electrode layer having a high contact resistance, or a semiconductor layer having a low electrical conductivity (hereinafter, referred to as an insulator layer and the like 112 ) is disposed on a surface of a p-type semiconductor layer 111 , a transparent electrode layer 113 A is disposed so as to cover these layers, and a p-side pad electrode 114 A is disposed at a position facing the insulator layer and the like 112 across the transparent electrode layer 113 A. Since the transparent electrode layer 113 A is generally formed by sputtering, a film thickness of the transparent electrode layer 113 A becomes thin at a step portion S (side face portion of the insulator layer and the like 112 ) of the transparent electrode layer 113 A indicated by dotted lines in FIG. 8A . As a result, a breakdown or disconnection (so-called open failure) is likely to be caused at the step portion S due to current concentration.
[0009] In order to solve the foregoing problem, another semiconductor light emitting element with a structure schematically shown in FIG. 8B has been proposed (see, for example, Patent Documents 9 to 13). A semiconductor light emitting element 110 B has the structure, in which the insulator layer and the like 112 is disposed on a surface of the p-type semiconductor layer 111 , a transparent electrode layer 113 B having a height substantially identical to that of the insulator layer and the like 112 is disposed on the p-type semiconductor layer 111 , and a p-side pad electrode 114 B is disposed so as to cover the insulator layer and the like 112 and a part of the transparent electrode layer 113 B. By setting a contact area between the p-side pad electrode 114 B and the transparent electrode layer 113 B to be large, the contact area is prevented from generating a current concentration.
[Patent Document 1] JPn. Pat. Appln. KOKAI Publication No. H08-250768 [Patent Document 2] JPn. Pat. Appln. KOKAI Publication No. H09-36431 [Patent Document 3] JPn. Pat. Appln. KOKAI Publication No. H09-129921 [Patent Document 4] JPn. Pat. Appln. KOKAI Publication No. 2004-140416 [Patent Document 5] JPn. Pat. Appln. KOKAI Publication No. H09-129922 [Patent Document 6] JPn. Pat. Appln. KOKAI Publication No. H11-4020 [Patent Document 7] JPn. Pat. Appln. KOKAI Publication No. H11-87772 [Patent Document 8] JPn. Pat. Appln. KOKAI Publication No. 2003-174196 [Patent Document 9] JPn. Pat. Appln. KOKAI Publication No. H10-173224 [Patent Document 10] Pamphlet WO98/42030 [Patent Document 11] JPn. Pat. Appln. KOKAI Publication No. 2000-124502 [Patent Document 12] JPn. Pat. Appln. KOKAI Publication No. 2002-353506 [Patent Document 13] JPn. Pat. Appln. KOKAI Publication No. 2003-124517
SUMMARY OF THE INVENTION
[0023] However, as the semiconductor light emitting element 110 B shown in FIG. 8B , if an area of the p-side pad electrode 114 B is enlarged, an area where a light is absorbed by the p-side pad electrode 114 B increases, and as a result, a light emitting area decreases. On the other hand, if the contact area between the p-side pad electrode 114 B and the transparent electrode layer 113 B is reduced, the open failure is likely to be caused by the current concentration as with the semiconductor light emitting element 110 A shown in FIG. 8A .
[0024] When a light emitting apparatus is manufactured using a light emitting device, generally, a plurality of light emitting devices are connected in series. Therefore, if an open failure occurs in a transparent electrode layer of one of the plurality of light emitting devices, it happens that a current does not flow in all of the light emitting devices, in addition to no light emission of the light emitting device of the open failure, thereby resulting in losing a function as a light emitting apparatus. Therefore, it is important to avoid a generation of the open failure.
[0025] The present invention has been developed in consideration of the foregoing problem, and it is an object of the present invention to provide a semiconductor light emitting element which is capable of avoiding a generation of open failure of the semiconductor light emitting element by securing a current path if a disconnection is generated in a transparent electrode layer. In addition, it is another object of the present invention to provide a semiconductor light emitting device using the semiconductor light emitting element.
[0026] A semiconductor light emitting element according to the present invention includes: a first semiconductor layer; a light emitting layer disposed on the first semiconductor layer; a first pad electrode disposed on the first semiconductor layer so as to separate from the light emitting layer; a second semiconductor layer disposed on the light emitting layer; an insulator layer disposed on one part of areas of the second semiconductor layer and provided with a hole portion passing through in a thickness direction of the second semiconductor layer; a transparent electrode layer disposed continuously from the other part of areas of the second semiconductor layer to a part of an upper surface of the insulator layer; and a second pad electrode which is disposed in contact with the second semiconductor layer through the hole portion of the insulator layer and in contact with the transparent electrode layer at a position facing the insulator layer across the transparent electrode layer. In the semiconductor light emitting element, a contact resistance between the second pad electrode and the second semiconductor layer is larger than a contact resistance between the transparent electrode layer and the second semiconductor layer.
[0027] In the semiconductor light emitting element, when the transparent electrode layer is not disconnected, a current substantially does not flow between the second pad electrode and the second semiconductor layer because the contact resistance between the transparent electrode layer and the second semiconductor layer is different from the contact resistance between the second pad electrode and the second semiconductor layer, and a current flows between the transparent electrode layer and the second semiconductor layer. If the disconnection occurred in the transparent electrode layer, a current flows through a contact surface between the second pad electrode and the second semiconductor layer to form a current path by an overvoltage breakdown of the second semiconductor layer/light emitting layer/first semiconductor layer. Then, when a light emitting apparatus is formed using a plurality of the foregoing semiconductor light emitting elements, even if the disconnection occurred in the transparent electrode layer of one of the semiconductor light emitting elements, the current path is secured and the other semiconductor light emitting elements can be maintained to be capable of light emitting
[0028] In the semiconductor light emitting element according to the present invention, it is preferable that a thickness of the insulator layer is 10 to 500 nm, a thickness of the transparent electrode layer is 20 to 400 nm, and a thickness of the second pad electrode is 400 to 2000 nm.
[0029] By forming the thicknesses as described above, resistances of the transparent electrode layer and the second pad electrode can be made small. In addition, when there is no disconnection in the transparent electrode layer, a generation of current concentration from the second pad electrode toward just below thereof can be avoided.
[0030] In the semiconductor light emitting element according to the present invention, it is preferable that a shape of an opening of the hole portion in the insulator layer is circular or substantially circular, and an area of the opening is not more than 80% of a contact area between the insulator layer and the second semiconductor layer.
[0031] Since the shape of the opening of the hole portion in the insulator layer is a shape of a contact surface between the second pad electrode and the second semiconductor layer, if the transparent electrode layer is disconnected, a distribution of current passing through the contact surface can be homogenized by forming the shape in circular or substantially circular. In addition, by forming the area of the opening of the hole portion in the insulator layer not more than 80% of the contact area between the insulator layer and the second semiconductor layer, a light absorption by the second pad electrode can be made small.
[0032] In the semiconductor light emitting element according to the present invention, it is preferable that an average diameter of the hole portion of the insulator layer is not less than 16 μm.
[0033] By forming the average diameter as described above, the semiconductor light emitting element can be prevented from generating an open failure.
[0034] In the semiconductor light emitting element according to the present invention, it is preferable that the first semiconductor layer is disposed on a predetermined substrate.
[0035] By forming the semiconductor light emitting element on the predetermined substrate, a semiconductor light emitting device provided with a plurality of semiconductor light emitting elements can be easily formed.
[0036] The semiconductor light emitting device according to the present invention includes a plurality of semiconductor light emitting elements each of whose first semiconductor layer is disposed on a predetermined substrate and at least two of the semiconductor light emitting elements are connected in series.
[0037] In addition, another semiconductor light emitting device according to the present invention includes a plurality of the semiconductor light emitting elements disposed on a predetermined substrate and at least two of the semiconductor light emitting elements are connected in series.
[0038] In these semiconductor light emitting devices according to the present invention, even if one semiconductor light emitting element becomes unable to emit a light, the semiconductor light emitting device can be prevented from becoming unable to emit light as a whole.
[0039] According to a semiconductor light emitting element of the present invention, the semiconductor light emitting element can be prevented from generating an open failure even if a disconnection occurs in the transparent electrode layer, because the second pad electrode is in direct contact with the second semiconductor layer and a current flows through the contact surface by forming a current path. Therefore, in a semiconductor light emitting device using a plurality of semiconductor light emitting elements, or in a semiconductor light emitting device using a plurality of semiconductor light emitting elements which are disposed on a single substrate, the semiconductor light emitting device can be prevented from generating the condition that the semiconductor light emitting device does not emit light as a whole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] FIG. 1A is a top view showing a structure of a semiconductor light emitting element according to a first embodiment of the present invention;
[0041] FIG. 1B is a cross sectional view showing the structure of the semiconductor light emitting element according to the first embodiment taken along A-A line of FIG. 1A ;
[0042] FIG. 1C is a cross sectional view showing the structure of the semiconductor light emitting element according to the first embodiment taken along B-B line of FIG. 1A ;
[0043] FIG. 2A is a schematic illustration showing a brief structure of a light emitting apparatus constituted by using a semiconductor light emitting element shown in FIG. 1A to FIG. 1C , which is an example of a connecting structure using a direct current power source;
[0044] FIG. 2B is a schematic illustration showing a brief structure of a light emitting apparatus constituted by using a semiconductor light emitting element shown in FIG. 1A to FIG. 1C , which is an example of a connecting structure using an alternate current power source;
[0045] FIG. 3 is a top view showing a brief structure of a semiconductor light emitting element according to a second embodiment of the present invention;
[0046] FIG. 4 is a top view showing a brief structure of a semiconductor light emitting element according to a third embodiment of the present invention;
[0047] FIG. 5 is a top view showing a brief structure of a semiconductor light emitting element according to a fourth embodiment of the present invention;
[0048] FIG. 6A is a cross sectional view showing a brief structure of a semiconductor light emitting element according to the fourth embodiment taken along C-C line of FIG. 5 ;
[0049] FIG. 6B is a cross sectional view showing a brief structure of the semiconductor light emitting element according to the fourth embodiment taken along D-D line of FIG. 5 ;
[0050] FIG. 7 is a graph showing relationships between an open-circuit failure generation voltage (applied voltage) and a breakdown rate as well as an accumulated breakdown rate;
[0051] FIG. 8A is a cross sectional view showing an example of a structure of a conventional semiconductor light emitting element; and
[0052] FIG. 8B is a cross sectional view showing an another example of a structure of a conventional semiconductor light emitting element
DETAILED DESCRIPTION OF THE INVENTION
[0053] Hereinafter, embodiments of the present invention will be explained in detail by referring to drawings.
First Embodiment
[0054] A top view showing a brief structure of a semiconductor light emitting element according to the first embodiment of the present invention is shown in FIG. 1A , a cross sectional view taken along A-A line in FIG. 1A is shown in FIG. 1B , and a cross sectional view taken along B-B line in FIG. 1A is shown in FIG. 1B . This semiconductor light emitting element 10 includes a substrate 11 , a first semiconductor layer 12 , a light emitting layer 13 , a second semiconductor layer 14 , an insulator layer 15 , a transparent electrode layer 16 , a first pad electrode 17 and a second pad electrode 18 .
[0055] In FIG. 1A to FIG. 1C , one semiconductor light emitting element 10 is formed on a single substrate 11 , but the present invention is not limited to this. For example, a plurality of independent first semiconductor layers 12 may be formed on a surface of the single substrate 11 , and each of the foregoing layers and each of the foregoing electrodes may be formed on each of the first semiconductor layers 12 . An explanation will be given below of each foregoing element of the semiconductor light emitting element 10 .
[Substrate]
[0056] As a material of the substrate 11 , the material having a lattice matching which is capable of epitaxially growing a semiconductor (compound semiconductor) constituting the first semiconductor layer 12 is used. For example, Al 2 O 3 (sapphire), MgAl 2 O 4 (spinel), SiC, SiO 2 , ZnS, ZnO, Si, GaAs, C (diamond), LiNbO 3 (lithium niobate), and Nd 3 Ga 5 O 12 (neodymium gallium garnet) may be used. An area and thickness of the substrate 11 are not limited specifically.
[First Semiconductor Layer]
[0057] The first semiconductor layer 12 to be formed on a surface of the substrate 11 is constituted by an n-type semiconductor material which is formed by doping an n-type dopant in III-V group compound semiconductors. As the III-V group compound semiconductors, for example, GaN, AlN and InN or In α Al β Ga 1-α-β N (0≦α, 0≦β, 0<α+β≦1) which is a mixed crystal of GaN, AlN and InN, III-V group compound semiconductors which are formed in such a manner that a part of or all of III-group element in the In α Al β Ga 1-α-β N are substituted by, for example, B, or a part of N is substituted by other V-group elements such as P, As and Sb, GaAs-based compound semiconductors (for example, AlGaAs, InGaAs), InP-based compound semiconductors (for example, AlGaInP), and III-V group compound semiconductors such as InGaAsP which is a mixed crystal of GaAs-based compound semiconductor and InP-based compound semiconductor, may be used. In addition, as a n-type dopant, for example, Si, Ge, Sn, S, O, Ti and Zr, which are IV-group element or VI-group element, may be used.
[Second Semiconductor Layer]
[0058] The second semiconductor layer 14 to be formed on a surface of the light emitting layer 13 is constituted by a p-type semiconductor material which is formed by doping a p-type dopant in III-V group compound semiconductors. The III-V group compound semiconductors to be used for the second semiconductor layer 14 are identical to the III-V group compound semiconductors to be used for the first semiconductor layer 12 . Then, the descriptions will be omitted. As the p-type dopant, for example, Be, Zn, Mn, Cr, Mg and Ca may be used.
[Light Emitting Layer]
[0059] The light emitting layer 13 is formed on a surface of the first semiconductor layer 12 so as to separate from the first pad electrode 17 , while securing a formation area of the first pad electrode 17 , which is connected to a predetermined power source, on the first semiconductor layer 12 . The light emitting layer 13 has a function to radiate energy as a light which is generated by recombination of electrons and holes injected from the first semiconductor layer 12 and the second semiconductor layer 14 , respectively. In order to effectively develop the function, it is preferable that the light emitting layer 13 has a quantum well structure including a well layer and a barrier layer as a quantum structure.
[0060] Specifically, a semiconductor material constituting the light emitting layer 13 may be any one of a non-doped semiconductor, an n-type impurity doped semiconductor and a p-type impurity doped semiconductor. Especially, the non-doped semiconductor or the n-type impurity doped semiconductor is preferably used. Here, an undoped semiconductor may be used for the well layer and the n-type impurity doped semiconductor may be used for the barrier layer. In the quantum well structure, a wavelength of a light to be produced in the light emitting layer 13 can be adjusted by a species and an amount of the dopant doped in the well layer. For example, when the light emitting layer 13 consists of a III-V group compound semiconductor, a light having a wavelength of about 60-650 nm, preferably 380-560 nm, may be emitted. If the well layer contains Al, a light having a wavelength range which is unable to achieve by a conventional well layer of InGaN, specifically, about 365 nm that corresponds to a band gap energy of GaN, or shorter wavelength can be obtained. Then, depending on, for example, an application of the semiconductor light emitting element 10 , a species and an amount of the dopant doped in the well layer may be set in order to adjust a wavelength of the emitting light.
Modified Example of First Semiconductor Layer/Light Emitting Layer/Second Semiconductor Layer
[0061] Here, a brief explanation will be given of a modified example of the first semiconductor layer 12 /light emitting layer 13 /second semiconductor layer 14 . As a first modified example, a structure that stacks a contact layer/a clad layer in this order on the substrate 11 may be used as the first semiconductor layer 12 , and similarly, a structure that stacks a clad layer/a contact layer in this order on the light emitting layer 13 may be used as the second semiconductor layer 14 . As a second modified example, a structure that forms a buffer layer between the substrate 11 and the first semiconductor layer 12 , forms the light emitting layer 13 on the buffer layer, in addition, forms a buffer layer on the second semiconductor layer 14 and forms the insulator layer 15 as well as the transparent electrode layer 16 on the buffer layer, may be used. As a third modified example, the first semiconductor layer 12 and the second semiconductor layer 14 each having a multi-layer structure that stacks an undoped semiconductor layer and a doped semiconductor layer alternately may be used.
[First Pad Electrode]
[0062] The first pad electrode 17 has a role as a terminal for electrically connecting a predetermined power source and the first semiconductor layer 12 , and a role as a terminal for connecting a plurality of the semiconductor light emitting elements 10 in series (see FIG. 2A and FIG. 2B , which will be described later). In the semiconductor light emitting element 10 , as shown in FIG. 1A and FIG. 1C , the first pad electrode 17 is formed on a step surface which is formed by cutting a part of an upper surface of the first semiconductor layer 12 , in order to separate (not to directly contact with each other) the light emitting layer 13 formed on an upper surface of the first semiconductor layer 12 from the first pad electrode 17 . Meanwhile, the first pad electrode 17 may be disposed on a surface of the first semiconductor layer 12 without forming the step surface separated (electrical insulation) from the light emitting layer 13 .
[0063] The first pad electrode 17 is in contact with the first semiconductor layer 12 with a low resistance. Hereinafter, in the specification, a state that a semiconductor material is in contact with an electrode material with a low resistance within a driving voltage of the semiconductor light emitting element 10 is referred to as “ohmic contact” (Therefore, the first pad electrode 17 is in contact with the first semiconductor layer 12 with ohmic contact). On the other hand, a state of a contact with a resistance higher than the ohmic contact is referred to as “Schottky contact”. There is such a difference of resistance between the ohmic contact and the Schottky contact that when a current flows through the ohmic contact, substantially, no current flows through the Schottky contact in the structure where an ohmic contact and a Schottky contact are formed in parallel.
[0064] From the foregoing point of view, as a material of the first pad electrode 17 , Ti, Al, Cr, Mo, W, Ag, and ITO which have a low contact resistance with the first semiconductor layer 12 , or alloys containing at least one of these metals are preferably used for a layer in contact with the first semiconductor 12 . The layer may be a single layer or a multilayer. Especially, a multilayer such as Ti/Rh/Au, Ti/Pt/Au, Ti/Ir/Au, Ti/Ru/Au, or Al—Si—Cu alloy/W/Au is preferably used because the first pad electrode 17 and the second pad electrode 18 can be formed concurrently. As the multilayer, specifically, the multilayer of Ti/Rh/Au each having a thickness of 2 nm/200 nm/500 nm may be used.
[Insulator Layer]
[0065] The insulator layer 15 has a function to reduce a light absorption by the second pad electrode 18 by reflecting the light emitted from the light emitting layer 13 . Therefore, as a material of the insulator layer 15 , the material having a refractive index smaller than that of the second semiconductor layer 14 , for example, SiO 2 , Al 2 O 3 , SiN, MgF 2 , CaF 2 , LiF, AlF 3 , BaF 2 , YF 3 , LaF 3 , CeF 3 , Y 2 O 3 , ZrO 2 , and Ta 2 O 5 may be used.
[0066] In addition, the insulator layer 15 has a function to homogenize a current flowing in the second semiconductor layer 14 . Namely, if the insulator layer 15 is not disposed, a current from the second pad electrode 18 concentrates in an area of the transparent electrode layer 16 located just below the second pad electrode 18 . As a result, the current in the second semiconductor layer 14 becomes inhomogeneous, and accordingly, the luminous efficiency may be decreased due to insufficient utilization of area of the light emitting layer 13 . However, by disposing the insulator layer 15 , the area located just below the second pad electrode 18 can be prevented from generating the current concentration and the lowering of the luminous efficiency can be suppressed.
[0067] A thickness of the insulator layer 15 is preferably set to 10-750 nm. If the thickness is less than 10 nm, it is difficult to suppress the current concentration effectively. On the other hand, if the thickness is more than 750 nm, when the transparent electrode 16 is formed, a thickness of the transparent electrode layer 16 in the vicinity of a side face of the insulator 15 becomes thin due to the thick insulator layer 15 . If the thin portion is formed once in the film of the transparent electrode layer 16 as described above, an open failure is likely to be caused in the thin portion due to a concentrated current from the second pad electrode 18 . The thickness of the insulator layer 15 is, more preferably, set to 250-600 nm.
[0068] The insulator layer 15 is provided with a hole portion 19 . With respect to a role of the hole portion 19 and a shape setting condition thereof, explanations will be given later together with the explanation of a function of a contact surface between the second pad electrode 18 and the second semiconductor layer 14 .
[Transparent Electrode Layer]
[0069] The transparent electrode layer 16 is formed to cover an upper surface of the insulator layer 15 except for the hole portion 19 of the insulator layer 15 , and substantially a whole area of an upper surface of the second semiconductor layer 14 , where the insulator layer 15 is not formed. The transparent electrode 16 has a role to electrically connect the second pad electrode 18 and the second semiconductor layer 14 and to supply a current to the second semiconductor layer 14 . In the normal use condition (condition of no disconnection in the transparent electrode layer 16 ) of the semiconductor light emitting element 10 , the transparent electrode layer 16 forms an ohmic contact with the second semiconductor layer 14 so that a current flows between the second pad electrode 18 and the second semiconductor layer 14 through the transparent electrode 16 .
[0070] In addition, the transparent electrode layer 16 has a role to radiate a light emitted from the light emitting layer 13 to outside through thereof. Therefore, especially, a material which has a large light transmission rate in the wavelength range of a light emitted from the light emitting layer 13 is preferably used for the transparent electrode layer 16 . For example, oxides containing at least one selected from In, Zn, Sn, Ga, W and Ti, specifically, ITO, IZO, ZnO, In 2 O 3 , SnO 2 and TiO 2 , and composite oxides thereof are used for the transparent electrode layer 16 . Meanwhile, as the transparent electrode layer 16 , a Ni/Au stack film may also be used.
[0071] A thickness of the transparent electrode layer 16 is preferably set to 20-400 nm for enabling the light emitting layer 13 to emit a light homogeneously in a large area by a current flowing homogeneously in the second semiconductor layer 14 except for the area just below the insulator layer 15 , and for suppressing absorption of light emitted from the light emitting layer 13 by the transparent electrode layer 16 .
[0072] It is noted that a film thickness of the transparent electrode layer 16 in the vicinity of a side face of the insulator layer 15 is formed to be thin in comparison with that of an upper portion of the second semiconductor layer 14 and that of an upper portion of the insulator layer 15 . This is caused by a film thickness of the insulator layer 15 and a film forming method (this will be described later) of the transparent electrode layer 16 . In this sense, the structure has a similar structure to that shown in FIG. 8A , which was explained as the prior art.
[Second Pad Electrode]
[0073] The second pad electrode 18 has a role as a terminal to electrically connect a predetermined power source and the transparent electrode layer 16 and a role as a terminal to connect a plurality of the semiconductor light emitting elements 10 in series or in parallel. In order to prevent a light generated in the light emitting layer 13 from being absorbed by the second pad electrode 18 , the second pad electrode 18 is disposed on a surface of the transparent electrode layer 16 above the insulator layer 15 so that the outer periphery of the second pad electrode 18 is located inside the outer periphery of the insulator layer 15 , or overlap with the outer periphery of the insulator layer 15 .
[0074] The second pad electrode 18 is in contact with the second semiconductor layer 14 through the hole portion 19 of the insulator layer 15 . Here, a contact resistance between the second pad electrode 18 and the second semiconductor layer 14 is larger than that between the second pad electrode 18 and the second semiconductor layer 14 through the transparent electrode layer 16 . Namely, the second pad electrode 18 forms a Schottky contact with the second semiconductor layer 14 . Therefore, in the normal use condition, as described above, a current flows from the second pad electrode 18 to the second semiconductor layer 14 through the transparent electrode layer 16 , however, the current does not flow directly from the second pad electrode 18 to the second semiconductor layer 14 through the hole portion 19 of the insulator layer 15 .
[0075] It is preferable that the second pad electrode 18 has a single layer structure or a multilayer structure including a layer which is in contact with the second semiconductor layer 14 and made of Ti, W, Nb, Al, Sn, Si, Hf, Y, Fe, Zr, V, Mn, Gd, Ir, Pt, Ru, Ta or Cr that is a material having a large contact resistance with the second semiconductor layer 14 , or made of alloys containing at least one of these metals. Especially, if Ti is used in a portion in contact with the second semiconductor layer 14 , Ti forms a Schottky contact with a p-type semiconductor that is used for the second semiconductor layer 14 , while Ti forms an ohmic contact with an n-type semiconductor that is used for the first semiconductor layer 12 and with various kinds of oxides that are used for the transparent electrode layer 16 . Therefore, it is preferable to form the first pad electrode 17 and the second pad electrode 18 concurrently. Accordingly, a multilayer structure such as Ti/Rh/Au, Ti/Pt/Au, Ti/Ir/Au, Ti/Ru/Au and Al—Si—Cu alloy/W/Pt/Au are preferably used.
[Function of Schottky Contact Between Second Pad Electrode and Second Semiconductor Layer]
[0076] As described above, a film thickness of the transparent electrode layer 16 is thin in the vicinity of a side face of the insulator layer 15 . Then, a disconnection may occur due to, for example, a current concentration at the thin portion. If the disconnection occurs in the transparent electrode layer 16 , a current does not flow from the second pad electrode 18 to the second semiconductor layer 14 through the transparent electrode layer 16 . However, in the light emitting device 10 , if the disconnection occurs in the transparent electrode layer 16 , a current flows from the second pad electrode 18 to the second semiconductor layer 14 through a Schottky contact surface (hereinafter, simply referred to as Schottky contact) between the second pad electrode 18 and the second semiconductor layer 14 . Due to the current at this time, an overvoltage breakdown is caused in the first semiconductor layer 12 /light emitting layer 13 /second semiconductor layer 14 to form a short circuit, thereby resulting in securing a current path. Therefore, for example, in a light emitting apparatus that connects a plurality of the semiconductor light emitting elements 10 in series, a current path is secured although the semiconductor light emitting element that is disconnected in the transparent electrode layer 16 does not emit a light. As a result, current supplies to the other semiconductor light emitting elements do not stop, and light emissions of the other semiconductor light emitting elements can be maintained.
[0077] A planer shape of the hole portion 19 disposed in the insulator layer 15 is identical to a shape of the Schottky contact. By forming the shape in circular or ellipsoidal, if a disconnection occurs in the transparent electrode layer 16 , a distribution of a current passing through the Schottky contact is likely to be homogeneous, and a current pass directed from the Schottky contact to the first pad electrode 17 can be surely formed when an overvoltage breakdown is caused in the first semiconductor layer 12 /light emitting layer 13 /second semiconductor layer 14 .
[0078] An area of the Schottky contact is identical to an opening area of the hole portion 19 of the insulator layer 15 , and it is preferable that the opening area of the hole portion 19 is not more than 80% of a contact area between the insulator layer 15 and the second semiconductor layer 14 . This is because when the semiconductor light emitting element 10 is normally used, the second pad electrode 18 absorbs a light emitted in the light emitting layer 13 through the Schottky contact. Then, by forming the area of the Schottky contact to be small, the light absorption by the second pad electrode 18 can be made small.
[0079] It is preferable that an average diameter of the hole portion 19 of the insulator layer 15 is not less than 16 μm. Here, the average diameter means that if the planer shape (that is, the shape of the Schottky contact) of the hole portion 19 is not circular, for example, if the shape is ellipsoidal, the average diameter is an average length of the major axis and the minor axis, and if the shape is square, the average diameter is a diameter of a circle having the same area with the square. As shown in the embodiment described later, if the average diameter of the hole portion 19 is not less than 16 μm, when an open failure occurs in the transparent electrode layer 16 , a current path can be surely formed by causing an overvoltage breakdown in the first semiconductor layer 12 /light emitting layer 13 /second semiconductor layer 14 by the current passing through the Schottky contact.
[0080] Meanwhile, a bonding wire is bonded to the second pad electrode 18 in order to connect the second pad electrode 18 to a power source or another semiconductor light emitting element 10 . The boding wire is preferably bonded to the upper center (an area above the hole portion 19 of the insulator 15 ) of the second pad electrode 18 . Then, a current flowing in the second pad electrode 18 can be made homogeneous, and if a disconnection occurs in the transparent electrode layer 16 , a current tends to flow toward the Schottky contact just below the upper center of the second pad electrode 18 . Therefore, it is likely to cause an overvoltage breakdown in the first semiconductor layer 12 /light emitting layer 13 /second semiconductor layer 14 , and likely to form a current path.
[Light Emitting Apparatus]
[0081] In FIG. 2A and FIG. 2B , a schematic illustration showing a brief configuration (that is, a connecting structure of semiconductor light emitting elements) of a light emitting apparatus using a semiconductor light emitting element according to the foregoing first embodiment is shown. Here, an example of a connecting structure that uses a direct current is shown in FIG. 2A , and an example of a connecting structure that uses an alternative current is shown in FIG. 2B . Meanwhile, since a structure of the semiconductor light emitting element 10 constituting each of the light emitting apparatuses shown in FIG. 2A and FIG. 2B is obvious from FIG. 1A to FIG. 1C , explanations on elements of the semiconductor light emitting element 10 are omitted in FIG. 2A and FIG. 2B .
[0082] The light emitting apparatus shown in FIG. 2A has a structure that connects a plurality (12 pieces are exemplified in FIG. 2A ) of the semiconductor light emitting elements 10 in series in a line by bonding wires, and the semiconductor light emitting elements 10 can be turned on simultaneously using a direct current power source. The light emitting apparatus shown in FIG. 2B has a structure that connects two line units, each consisting of a plurality (6 pieces in FIG. 2B ) of the semiconductor light emitting elements 10 connected in series in a line by bonding wires, in parallel against an alternative current power source, and currents flowing in the two line units have opposite directions to each other (when a current flows in one line unit, no current flows in the other line unit). Namely, the light emitting apparatus shown in FIG. 2B has a structure where the semiconductor light emitting elements 10 in each of the line units alternately emit lights by line unit, depending on a frequency of the alternative current output from the alternative current power source.
[0083] In these light emitting apparatuses, even if a disconnection (breakdown) is generated in the transparent electrode layer 16 of one semiconductor light emitting element 10 , the semiconductor light emitting element 10 is prevented from generating an open failure since a current path passing through the foregoing Schottky contact and the first semiconductor layer 12 /light emitting layer 13 /second semiconductor layer 14 is formed between the second pad electrode 18 and the first pad electrode 17 . Then, even if one semiconductor light emitting element 10 becomes unable to emit a light, the remaining eleven semiconductor light emitting elements 10 can maintain the condition capable of emitting a light. Meanwhile, in FIG. 2A and FIG. 2B , for example, the twelve semiconductor light emitting elements 10 may be disposed on a single substrate. In addition, a plurality of the light emitting apparatus, shown in FIG. 2A and FIG. 2B , consisting of the twelve semiconductor light emitting elements 10 may be further connected in series in order to form another new light emitting apparatus.
[Fabrication Method of Semiconductor Light Emitting Element]
[0084] The fabrication method of the semiconductor light emitting element 10 is briefly described by the following steps.
[0000] (1) Formation of the first semiconductor layer 12 , the light emitting layer 13 and the second semiconductor layer 14 on a substrate surface.
(2) Formation of the insulator layer 15 and the transparent electrode layer 16 .
(3) Etching a part of area in order to form the first pad electrode 17 .
(4) Formation of the first pad electrode 17 and the second pad electrode 18 .
[0085] Explanations of the steps (1) to (4) will be given below.
[Formation of First Semiconductor Layer, Light Emitting Layer, and Second Semiconductor Layer]
[0086] The first semiconductor layer, the light emitting layer, and the second semiconductor layer can be formed by growing a semiconductor (compound semiconductor) on a surface of a cleaned substrate 11 using a gas containing, for example, a predetermined semiconductor material and dopants with various kinds of vapor phase epitaxy such as MOVPE (metal-organic vapor phase epitaxy), HDVPE (halide vapor phase epitaxy), MBE (molecular beam epitaxy), and MOMBE (metal-organic molecular beam epitaxy). In this case, according to a composition of the semiconductor layer (first semiconductor layer 12 consisting of n-type semiconductor/light emitting layer 13 /second semiconductor layer 14 consisting of p-type semiconductor) to be formed, a gas species is changed and a growth time is adjusted depending on a film thickness of each of the semiconductor layers, and as a result, these semiconductor layers can be formed continuously.
[Formation of Insulator Layer and Transparent Electrode Layer]
[0087] The insulator layer 15 having a planar ring shape is formed on a part of a surface of the second semiconductor layer 14 . For example, the insulator layer 15 may be formed by growing a material composing the insulator layer 15 on a predetermined area by sputtering and the like using a photomask, and removing the photomask thereafter.
[0088] The transparent electrode layer 16 may be formed by growing a conductive oxide containing at least one selected from In, Zn, Sn, and Ga on a whole surface of the insulator layer 15 , for example, after the insulator layer 15 is formed, and subsequently conducting etching on the area (that is, the area of the hole portion 19 and its vicinity of the insulator layer 15 and the area for forming the first pad electrode 17 ) that the transparent electrode layer 16 is unnecessary.
[Partial Etching for Forming First Pad Electrode 17 ]
[0089] An etching mask is formed except for an area for forming the first pad electrode 17 , etching is conducted until a mid depth of the first semiconductor layer 12 by, for example, dry etching, and after that, the etching mask is removed. Thus, the area for disposing the first pad electrode 17 can be formed.
[Formation of First Pad Electrode and Second Pad Electrode]
[0090] The first pad electrode 17 and the second pad electrode 18 may be formed concurrently in such a manner that, for example, a resist pattern is formed so that areas for forming the first pad electrode 17 and the second pad electrode 18 are exposed, then, Ti/Rh/Au are grown sequentially by using, for example, spattering. After that, the resist pattern is removed. It is noted that the fabrication method of the semiconductor light emitting element 10 is not limited to the foregoing processes. For example, the following processes may be applied to the fabrication method. After the first semiconductor layer 12 /light emitting layer 13 /second semiconductor layer 14 are formed, an area for forming the first pad electrode 17 is formed by etching. Then, the first pad electrode 17 is formed, and subsequently, the insulator layer 15 , the transparent electrode layer 16 and the second pad electrode 18 are formed sequentially.
Second Embodiment
[0091] FIG. 3 is a top view showing a brief structure of a semiconductor light emitting element according to a second embodiment of the present invention. An element of a semiconductor light emitting element 10 A shown in FIG. 3 and having a function identical to that of the semiconductor light emitting element 10 shown in FIG. 1A to FIG. 1C has the same reference number with that of the semiconductor light emitting element 10 in the drawings and the explanation. This is the same with semiconductor light emitting elements according to a third embodiment and a fourth embodiment, which will be described later.
[0092] FIG. 3 is drawn in a similar manner to FIG. 1A , and the semiconductor light emitting element 10 A has a shape of substantially square in plan view and includes the substrate 11 , the first semiconductor layer 12 (overlapped with the substrate 11 ) formed on the substrate 11 , the first pad electrode 17 disposed at a corner portion on the first semiconductor layer 12 , the light emitting layer 13 disposed on the first semiconductor layer 12 separated from the first pad electrode 17 , the second semiconductor layer 14 (overlapped with the light emitting layer 13 ) disposed on the light emitting layer 13 , and the insulator layer 15 disposed on the second semiconductor layer 14 .
[0093] The insulator layer 15 is disposed on a part of an upper surface of the second semiconductor layer 14 and includes a nearly circular core portion disposed at a corner portion which is located diagonally to the corner portion where the first pad electrode 17 is disposed and an extending portion extending along a side direction of the second semiconductor layer 14 from the core portion. The foregoing shape of the insulator layer 15 is formed corresponding to a shape of the second pad electrode 18 . The hole portion 19 passing through in the thickness direction is disposed near the center of the core portion.
[0094] In addition, the semiconductor light emitting element 10 A includes the transparent electrode layer 16 , which covers an upper surface of the insulator layer 15 without covering the hole portion 19 of the insulator layer 15 as well as an area where the insulator layer 15 is not formed on the second semiconductor layer 14 , and the second pad electrode 18 which is in contact with the second semiconductor layer 14 through the hole portion 19 of the insulator layer 15 and located at a position facing the insulator layer 15 across the transparent electrode layer 16 so as to come in contact with the transparent electrode layer 16 .
[0095] In the plan view shown in FIG. 3 , the second pad electrode 18 has a size to fall inside the insulator layer 15 . The second pad electrode 18 includes a core portion 40 disposed on the core portion of the insulator layer 15 and extending portions 41 a , 41 b disposed on respective extending portions of the insulator layer 15 . By disposing the extending portions 41 a , 41 b as described above, a current in a whole surface of the second semiconductor layer 14 can be made homogeneous. As a result, a light emission that effectively utilizes a light emitting area of the light emitting layer 13 becomes possible. In addition, by adjusting a shape of the insulator layer 15 to that of the second pad electrode 18 , a generation of current concentration just below the second pad electrode 18 can be avoided.
[0096] Meanwhile, with respect to a current flow to the second semiconductor layer 14 from the second pad electrode 18 in the case
[0097] that the second pad electrode 18 is provided with the extending portions 41 a , 41 b , it is thought that a current flow (current density) to the second semiconductor layer 14 from the core portion 40 is larger than a current flow to the second semiconductor layer 14 from the extending portions 41 a , 41 b . Therefore, a structure which is provided with the insulator layer 15 only just below the core portion 40 of the second pad electrode 18 may be adopted.
[0098] The transparent electrode 16 forms an ohmic contact with the second semiconductor layer 14 , and the second pad electrode 18 forms a Schottky contact with the second semiconductor layer 14 . Namely, although a planar structure of the semiconductor light emitting element 10 A is different from that of the semiconductor light emitting element 10 in FIG. 1A to FIG. 1C , as described above, a cross sectional structure of the semiconductor light emitting element 10 A is identical to that of the semiconductor light emitting element 10 in FIG. 1A to FIG. 1C described above. Therefore, if the transparent electrode layer 16 is disconnected, a current flows through the Schottky contact between the second pad electrode 18 and the second semiconductor layer 14 while securing a current path, and as a result, the semiconductor light emitting element 10 A can be prevented from generating an open failure.
Third Embodiment
[0099] A top view showing a brief structure of a semiconductor light emitting element according to a third embodiment of the present invention is shown in FIG. 4 . FIG. 4 is drawn in a similar manner to FIG. 1A , and a semiconductor light emitting element 10 B has a shape of substantially square and includes the substrate 11 , the first semiconductor layer 12 (overlapped with the substrate 11 ) formed on the substrate 11 , and the first pad electrode 17 disposed on one end of the first semiconductor layer 12 in the longitudinal direction of the first semiconductor layer 12 . The first pad electrode 17 includes a core portion 42 disposed at an end on the first semiconductor layer 12 in the longitudinal direction of the first semiconductor layer 12 and an extending portion 43 extending form the core portion 42 along a long side of the first semiconductor layer 12 .
[0100] In addition, the semiconductor light emitting element 10 B includes the light emitting layer 13 disposed on the first semiconductor layer 12 separated from the first pad electrode 17 , the second semiconductor layer 14 (overlapped with the light emitting layer 13 ) formed on the light emitting layer 13 , and the insulator layer 15 formed on the second semiconductor layer 14 . The insulator layer 15 includes a core portion disposed on the second semiconductor layer 14 at an end in the longitudinal direction opposite to the first pad electrode 17 and an extending portion extending from the core portion along the long side. The foregoing shape of the insulator layer 15 is formed corresponding to a shape of the second pad electrode 18 . In addition, the hole portion 19 passing through in the thickness direction is disposed near the center of the core portion.
[0101] In addition, the semiconductor light emitting element 10 B includes the transparent electrode layer 16 , which covers an upper surface of the insulator layer 15 without covering the hole portion 19 of the insulator layer 15 and an area where the insulator layer 15 is not formed on the second semiconductor layer 14 , and the second pad electrode 18 which is in contact with the second semiconductor layer 14 through the hole portion 19 of the insulator layer 15 and located at a position facing the insulator layer 15 across the transparent electrode layer 16 so as to come in contact with the transparent electrode layer 16 .
[0102] In the plan view shown in FIG. 4 , the second pad electrode 18 has a size to fall inside the insulator layer 15 . The second pad electrode 18 includes the core portion 40 disposed on the core portion of the insulator layer 15 and an extending portion 41 disposed on the extending portion of the insulator layer 15 . By disposing the extending portion 41 in the second pad electrode 18 as well as disposing the extending portion 43 in the first pad electrode 17 , a current in a whole surface of each of the first semiconductor layer 12 and the second semiconductor layer 14 can be made homogeneous. As a result, alight emission that effectively utilizes alight emitting area of the light emitting layer 13 becomes possible. In addition, by adjusting a shape of the insulator layer 15 to that of the second pad electrode 18 , a generation of current concentration just below the second pad electrode 18 can be avoided. It is noted that even if the second pad electrode 18 includes the extending portion 41 , the insulator layer 15 may be disposed only just below the core portion 40 .
[0103] The transparent electrode 16 forms an ohmic contact with the second semiconductor layer 14 , and the second pad electrode 18 forms a Schottky contact with the second semiconductor layer 14 . Namely, although a planar structure of the semiconductor light emitting element 10 B is different from that of the semiconductor light emitting element 10 in FIG. 1A to FIG. 1C as described above, a cross sectional structure of the semiconductor light emitting element 10 B is identical to that of the foregoing semiconductor light emitting element 10 in FIG. 1A to FIG. 1C . Therefore, when the transparent electrode layer 16 is disconnected, a current flows through the Schottky contact between the second pad electrode 18 and the second semiconductor layer 14 while securing a current path, and as a result, the semiconductor light emitting element 10 B can be prevented from generating an open failure.
Fourth Embodiment
[0104] A top view showing a brief structure of a semiconductor light emitting element according to a fourth embodiment of the present invention is shown in FIG. 5 . FIG. 6A is a cross sectional view of the semiconductor light emitting element taken along C-C line of FIG. 5 , and FIG. 6B is a cross sectional view of the semiconductor light emitting element taken along D-D line of FIG. 5 . The semiconductor light emitting element 10 C has a structure provided with two light emitting portions connected in parallel. The semiconductor light emitting element 10 C includes the substrate 11 and the first semiconductor layer 12 formed on the substrate 11 , and areas of the respective light emitting portions are allocated on the common first semiconductor layer 12 .
[0105] The each light emitting portion is provided with the first pad electrode 17 formed on the first semiconductor layer 12 , and the first pad electrode 17 includes a core portion 42 having a nearly circular shape in plan view and an extending portion 43 extending through the core portion 42 in the radial direction. The light emitting layer 13 is formed on the first semiconductor layer 12 so as to separate from the first pad electrode 17 , and the second semiconductor layer 14 is disposed on the light emitting layer 13 . As shown in FIG. 6A , the light emitting layer 13 is common to the two light emitting portions and the second semiconductor layer 14 is also common to the two light emitting portions. Namely, areas of respective light emitting portions are allocated to the common light emitting layer 13 and to the common second semiconductor layer 14 .
[0106] The semiconductor light emitting element 10 C has such a structure that the second pad electrode 18 surrounds a periphery of the first pad electrode 17 , and the second pad electrodes 18 provided in respective light emitting portions are connected to each other. The second pad electrode 18 includes core portions 40 disposed at two corner portions on the short side of respective light emitting portions and extending portions 41 extending from the core portion 40 along the long side. The insulator layer 15 is formed on the second semiconductor layer 14 corresponding to a shape of the second pad electrode 18 , and a shape of the insulator layer 15 is designed so that the second pad electrode 18 is fallen inside the insulator layer 15 in plan view shown in FIG. 5 .
[0107] The semiconductor light emitting element 10 C includes the insulator layer 15 , the transparent electrode layer 16 , the first pad electrode 17 and the second pad electrode 18 . The first pad electrode 17 includes the core portion 42 and the extending portion 43 , the second pad electrode 18 includes the core portion 40 and the extending portion 41 , and the insulator layer 15 has a shape corresponding to that of the second pad electrode 18 so that the second pad electrode 18 is fallen inside the insulator layer 15 in plan view shown in FIG. 5 . The hole portion 19 passing through in the thickness direction is disposed in an area lower than the core portion 40 in the second pad electrode 18 and the insulator layer 15 .
[0108] The each light emitting portion includes the transparent electrode layer 16 which covers an upper surface of the insulator layer 15 without covering the hole portion 19 of the insulator layer 15 and an area where the insulator layer 15 is not formed on the second semiconductor layer 14 . The second pad electrode 18 having the foregoing shape is, as shown in FIG. 6A , disposed in such a manner that the second pad electrode 18 is in contact with the second semiconductor layer 14 through the hole portion 19 of the insulator layer 15 and located at a position facing the insulator layer 15 across the transparent electrode layer 16 so as to come in contact with the transparent electrode layer 16 .
[0109] By disposing the extending portions 41 in the second pad electrode 18 as well as disposing the extending portion 43 in the first pad electrode 17 , a current in a whole surface of each of the first semiconductor layer 12 and the second semiconductor layer 14 can be made homogeneous. As a result, a light emission that effectively utilizes a light emitting area of the light emitting layer 13 becomes possible. In addition, by adjusting a shape of the insulator layer 15 to that of the second pad electrode 18 , a generation of current concentration just below the second pad electrode 18 can be avoided. It is noted that even if the second pad electrode 18 includes the extending portion 41 , the insulator layer 15 may be disposed only just below the core portion 40 .
[0110] The transparent electrode 16 forms an ohmic contact with the second semiconductor layer 14 , and the second pad electrode 18 forms a Schottky contact with the second semiconductor layer 14 . Therefore, if the transparent electrode layer 16 is disconnected, a current flows through the Schottky contact between the second pad electrode 18 and the second semiconductor layer 14 while securing a current path, and as a result, the semiconductor light emitting element 10 C can be prevented from generating an open failure.
[0111] Explanations for the semiconductor light emitting elements 10 , 10 A, 10 B and 10 C according to the embodiments 1 to 4 of the present invention have been made. However, the present invention is not limited to these embodiments and, for example, a shape of the light emitting device in plan view may be oval, parallelogram or polygonal, other than square or oblong (rectangle). In addition, in the first to fourth embodiments, the first pad electrode is formed on a side identical to the side of the second pad electrode as seen from the substrate. However, the arrangements of the first pad electrode and the second pad electrode are not limited to this, and a structure having no substrate or having a conductive substrate may be adopted and, for example, the first pad electrode on the first semiconductor layer may be disposed on a side opposite to the semiconductor light emitting element across the semiconductor layers and the second pad electrode.
EXAMPLES
[0112] As a semiconductor light emitting element of EXAMPLE 1, a semiconductor light emitting element having a structure shown in FIG. 1 was fabricated. The semiconductor light emitting element of EXAMPLE 1 was fabricated by the following processes. A first semiconductor layer made of a GaN-based n-type semiconductor, a light emitting layer made of a GaN-based undoped semiconductor and a second semiconductor layer made of a GaN-based p-type semiconductor were sequentially formed on a sapphire substrate by MOCVD. After that, etching was conducted in order to form an area (see FIG. 1A ) for disposing a first pad electrode, and a part of the first semiconductor layer was exposed. Meanwhile, in order to concurrently fabricate a plurality of semiconductor light emitting elements of EXAMPLE 1, the first semiconductor layer/light emitting layer/second semiconductor layer were formed on the sapphire substrate.
[0113] Here, the first semiconductor layer had the following structure. A buffer layer (film thickness: about 10 nm) made of AlGaN was grown on the sapphire substrate. Subsequently, an undoped GaN layer (1 μm), an n-side contact layer (5 μm) made of GaN containing 4.5×10 18 /cm 3 of Si, an n-side first multilayer (total thickness: 335 nm) consisting of three layers of a bottom layer (300 nm) made of undoped GaN, an interlayer (30 nm) made of GaN containing 4.5×10 18 /cm 3 of Si and an upper layer (5 μm) made of undoped GaN, and an n-side second multilayer (total thickness: 64 nm) that is a superlattice structure where an undoped GaN layer (4 nm) and an undoped In 0.1 Ga 0.9 N layer (2 nm) were alternately stacked ten times for each and further, an undoped GaN layer (4 nm) was stacked, were grown in this order on the buffer layer.
[0114] Next, the light emitting layer was formed of a multiquantum well structure (total thickness: 193 nm) consisting of a barrier layer (25 nm) made of undoped GaN and a layer which was formed by stacking a well layer (3 nm) made of In 0.3 Ga 0.7 N, a first barrier layer (10 nm) made of In 0.02 Ga 0.98 N and a second barrier layer (15 nm) made of undoped GaN alternately six times for each layer.
[0115] In addition, the second semiconductor layer had a structure that sequentially stacked the p-side multilayer (total film thickness: 36.5 nm), which was formed of a superlattice structure formed by stacking a Al 0.15 Ga 0.85 N layer (4 nm) containing 5×10 19 /cm 3 of Mg and an In 0.03 Ga 0.97 N layer (2.5 nm) containing 5×10 19 /cm 3 of Mg alternately five times for each and further stacking another Al 0.15 Ga 0.85 N layer (4 nm) containing 5×10 19 /cm 3 of Mg, and a p-side contact layer (120 nm) made of GaN containing 1×10 20 /cm 3 of Mg, in this order.
[0116] At a predetermined position (see FIG. 1A ) on a surface of the second semiconductor layer that is a light emitting surface, an insulator layer made of SiO 2 having a flat ring shape which includes a hole portion having an inner diameter of 10 μm and has an outer diameter of 76 μm was grown 500 nm in thickness by sputtering. After that, a transparent electrode layer made of ITO provided with a hole portion having an inner diameter 6 μm larger (that is, inner diameter: 16 μm) than the diameter (hole diameter) of the hole portion of the insulator layer was grown 170 nm in thickness on the insulator layer and the second semiconductor layer.
[0117] In addition, the second pad electrode having a diameter of 70 μm was formed by spattering so as to directly contact with the second semiconductor layer through the hole portion of the insulator. A structure of the second pad electrode was a three-layered structure of Ti/Rh/Au, and thicknesses of the three layers were 1.5 nm/200 nm/500 nm, respectively. In addition, when the second pad electrode was formed, the first pad electrode was formed concurrently with the formation of the second pad electrode with a structure identical to that of the second pad electrode. Here, a shape of the first pad electrode in plan view was nearly circular having an average diameter of 70 μm. Meanwhile, the second pad electrode forms a Schottky contact with the second semiconductor layer (GaN-based p-type semiconductor), and the second pad electrode forms an ohmic contact with the transparent electrode (ITO). The first pad electrode forms an ohmic contact with the first semiconductor layer (GaN-based n-type semiconductor).
[0118] Next, a semiconductor light emitting element having a size of 500 μm×290 μm was cut out by dicing and bonded on a metal lead frame. Then, Au wire was bonded to each of the first pad electrode and the second pad electrode and the semiconductor light emitting element was molded with epoxy resin. According to the processes described above, the semiconductor light emitting element of EXAMPLE 1 was fabricated.
[0119] As a semiconductor light emitting element of EXAMPLE 2, a semiconductor light emitting element having a structure identical to that of the semiconductor light emitting element of EXAMPLE 1 except that a diameter of the hole portion of the insulator layer is 16 μm and that a diameter of the hole portion of the transparent electrode layer corresponding to the hole portion of the insulator layer is 22 μm was fabricated. Similarly, as semiconductor light emitting elements of EXAMPLES 3, 4, 5 and 6, semiconductor light emitting elements having structures identical to that of the semiconductor light emitting element of EXAMPLE 1 except that diameters of the hole portions of the insulator layers of EXAMPLES 3, 4, 5 and 6 are 22 μm, 28 μm, 34 μm and 40 μm, respectively and that diameters of the hole portions of the transparent electrode layers corresponding to the respective hole portions of the insulator layers are 28 μm, 34 μm, 40 μm and 46 μm, respectively were fabricated. In addition, as a semiconductor light emitting element of a COMPARATIVE EXAMPLE having a conventional structure, a semiconductor light emitting element (see FIG. 8A ) which has no hole portion in the insulator layer, that is, which has no area that the second pad electrode is in direct contact with the second semiconductor layer, was fabricated.
[0120] A voltage to generate an open failure in the semiconductor light emitting elements of the COMPARATIVE EXAMPLE and EXAMPLES 1 to 6 was investigated by applying a voltage of machine model between the first pad electrode and the second pad electrode and investigating an electric conduction between the first pad electrode and the second pad electrode. Meanwhile, generally, the applying a voltage of machine model is to charge up a capacitor of 200 pF at an appropriate voltage and to apply the voltage to a device, and may be conducted using, for example, electrostatic breakdown test equipment (Model: DWP-3000) manufactured by DAITRON TECHNOLOGY CO., LTD.
[0121] A graph showing relations between an open-circuit failure generation voltage (applied voltage) and a breakdown rate as well as an accumulated breakdown rate is shown in FIG. 7 . It is noted that in FIG. 7 , the breakdown rate (a ratio of open failure samples to total samples) is indicated by bar charts, and the accumulated breakdown rate is indicated by line charts. In addition, a value of the open-circuit failure generation voltage on the horizontal axis corresponds to the line charts (accumulated breakdown voltage), and the bar charts (breakdown rate) are shown at positions shifted from the actual open-circuit failure generation voltages, while the actual open-circuit failure generation voltages are shown near the bar charts.
[0122] With respect to the semiconductor light emitting element of the COMPARATIVE EXAMPLE, the open failure generation was not observed at applied voltage of 534V (that is, the semiconductor light emitting element was capable of emitting a light). However, at applied voltage of 640V, the open failure was generated in the semiconductor light emitting elements at a rate of 20%. In addition, at applied voltage of 747V, the open failure was generated in the semiconductor light emitting elements at a rate of 60% (The accumulated breakdown rate is 80%), and at applied voltage of 960V, the open failure was generated in the remaining 20% of the semiconductor light emitting elements (The accumulated breakdown rate is 100%). It was proven that the open failure generation in the COMPARATIVE EXAMPLE was caused by a disconnection of the transparent electrode layer.
[0123] On the other hand, in the semiconductor light emitting element of EXAMPLE 1, the open failure generation was not observed at applied voltage of 534 to 854V. Comparing this result with that of the COMPARATIVE EXAMPLE, it was considered that although the transparent electrode layer was disconnected at the applied voltage at 80% of the samples, a current path was secured in the first semiconductor layer/light emitting layer/second semiconductor layer due to a current flow through the Schottky contact between the second pad electrode and the second semiconductor layer. In the semiconductor light emitting element of EXAMPLE 1, the open failure was generated at 80% of the semiconductor light emitting elements by applied voltage of 960V, and at applied voltage of 1096V, the open failure was generated in the remaining 20% of the semiconductor light emitting elements. This was considered that a breakdown was caused by an excess current in the hole portion between the second semiconductor layer and the second pad electrode due to a small diameter of the hole portion disposed in the insulator layer. From the above facts, it can be seen that the semiconductor light emitting element of EXAMPLE 1 has a structure that the open-circuit failure generation voltage is high and the open failure is hardly caused in comparison with the semiconductor light emitting element of the COMPARATIVE EXAMPLE.
[0124] The open failure was not observed in the semiconductor light emitting elements of EXAMPLES 2 to 6 even if 1174V was applied to the devices. Then, the bar charts indicating the breakdown rates of the semiconductor light emitting elements of EXAMPLES 2 to 6 are not shown in FIG. 7 . This was considered that a current flowed through the Schottky contact between the second pad electrode and the second semiconductor layer and a current path in the first semiconductor layer/light emitting layer/second semiconductor layer was secured by enlarging a diameter of the hole portion disposed in the insulator layer larger than 16 μm, and thereby, the hole portion was also not broken by an excess current within the range of applied voltages of the present tests.
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Provided is a semiconductor light emitting element wherein generation of an open failure of the light emitting device can be eliminated by ensuring a current pathway when disconnection is generated in a transparent electrode layer. A semiconductor light emitting element ( 10 ) is provided with: a first semiconductor layer ( 12 ) on a substrate ( 11 ); a light emitting layer ( 13 ) on the first semiconductor layer ( 12 ); a second semiconductor layer ( 14 ) on the light emitting layer ( 13 ); an insulator layer ( 15 ) provided with a hole portion ( 19 ) in a partial region on the second semiconductor layer ( 14 ); a transparent electrode layer ( 16 ) covering the upper surface of the insulator layer ( 15 ) and the second semiconductor layer ( 14 ) without covering the hole portion ( 19 ); and a second pad electrode ( 18 ) brought into contact with the second semiconductor layer ( 14 ) through the hole portion ( 19 ) and faces the insulator layer ( 15 ) with the transparent electrode layer ( 16 ) therebetween. Contact resistance between the second pad electrode ( 18 ) and the second semiconductor layer ( 14 ) is set larger than that between the transparent electrode layer ( 16 ) and the second semiconductor layer ( 14 ).
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This invention pertains to means for handling submersible equipment, which has a lifting bail, from a remote location, and to a method for doing the same.
BACKGROUND OF THE INVENTION
When handling equipment which is submersed in liquid, for instance a submersible pump, it is a normal practice to have a chain attached to the equipment. An end of the chain is held above the liquid level, and when the equipment has to be lifted (and subsequently lowered), a lifting hoist is attached to the out-of-liquid end of the chain. This procedure requires a somewhat laborious engagement of a hoist hook with a shackle, and the latter with a lifting bail, or handle, on the equipment. As this operation is troublesome and time consuming, another procedure has become common. In this, a hoisting hook has its safety lock disabled, and the hook is angled to find and engage the equipment, by snaring the lifting bail thereof for instance. This introduces a considerable safety risk to the personnel as, clearly, the equipment load may loosen from the un-safetied hook, especially with any oscillation or swinging of the hook suspended load.
Another problem, which is especially important in sewage pump stations, is that the original lifting chain of the pump unit corrodes at the liquid level and, therefore, must be replaced at recurring intervals.
One way to overcome these difficulties is to arrange a guide unit from above, i.e., from ground level, down to the submersed load, and permanently attached to the submersed load. A lifting device, then, is guided along the guide unit, and down to the submersed equipment, when the equipment must be raised to ground level. The guide unit, then, must be made of a material that does not corrode, e.g., nylon for instance, and be so thin or filamentary, that it would not be mistaken for a load-lifting agent.
An example of a lifting device which operates according to the aforesaid is shown in the Swedish Patent No. 810 2854-0. In this, a lifting eye is lowered down to a submersible pump along a guide cord, and is hooked to a short chain attached to the pump. This device has good functioning for moderate weight loads, but does not meet the requirements for heavy loads where the connection between the lifting device and the pump must be more solid.
In light of the foregoing, it is an object of this invention to set forth a means for, and a method of, handling a submersible equipment, comprising a lifting device of the type that is described in the Swedish Patent No. 900 1774-0. This lifting device includes a shackle which can be turned relative to the body of the lifting device. Too, the body is provided with a lock, acted upon by the shackle, which prevents a turning of the lifting hook during lifting and/or loading, and is so designed that an unloaded lifting hook takes an evacuating, open position.
SUMMARY OF THE INVENTION
It is an object of this invention, then, to set forth means for handling a submersible equipment which has a lifting bail, comprising a length of non-corroding, filamentary material; a hook; and means supporting said hook in suspension; wherein said filamentary material is in penetration of said lifting bail of said equipment; a first end of said filamentary material is coupled to said hook; said supporting means comprises means operative for moving said hook into proximity with said bail; and means for pulling a second end of said filamentary material, for (a) drawing said filamentary material through said bail, and (b) causing said hook to snare said bail.
It is also an object of this invention to disclose a method of handling a, submersible equipment which has a lifting bail, comprising the steps of penetrating the lifting bail of the equipment with a length of non-corroding, filamentary material; suspending a lifting hook; coupling one end of said filamentary material to the hook; moving the hook into proximity with the bail; and pulling a second end of the filamentary material to cause the hook to snare the bail.
Further objects of this invention, as well as the novel features thereof, will become apparent by reference to the following description, taken in conjunction with the accompanying figures.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical illustration of a submersible equipment, i.e., a pump, and the inventive handling means, according to an embodiment thereof, operatively engaged with the pump;
FIG. 2 is an illustration like that of FIG. 1 in which, however, the lifting hook has been lowered to, and has snared, the pump lifting bail;
FIG. 3 is a same vertical illustration wherein, now, the novel handling means is commencing to lift the pump;
FIG. 4 depicts a same vertical illustration in which, now, the filamentary material is relaxed in order that the lifting hook can be released from the bail;
FIG. 5 shows the novel handling means being withdrawn from the pump, having served its function, and being disposed in a storage status; and
FIG. 6 is a flow diagram of the novel method as disclosed herein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1, a pumping station 10 has a submersible pump 12 therein, the pump 12 has electrical cabling 14 connected thereto and a lifting bail 16 at the top thereof. A non-corroding, filamentary material 18 is in penetration of the bail 16. A hoist 20 has a chain 22 depending therefrom, the hoist 20 being set above ground level. The chain 22 is coupled to a first hook 24 which has a shackle 26 engaged therewith. A lower, depending end of the shackle 26 is pivotably coupled to a lifting hook body 28. A lifting hook 30 is also pivotably coupled to the body 28. A first end 32 of the length of filamentary material 18 is removably coupled to the tip of the hook 30. The opposite end 34 of the material 18 is connected to a take-up winch 36. A pair of limbs 38 and 40 are fixed to the body 28, and extend therefrom in a generally common direction. The limbs 38 and 40 have loops at the outermost ends thereof through which the material 18 is threaded. Consequently, the limbs 38 and 40 guide the winch-directed portion of the filamentary material 18 away from the lifting hook-directed portion thereof, so that the two portions will not become entangled inadvertently.
The aforementioned Swedish Patent No. 900 1774-0 is incorporated herein by reference, as it fully discloses the nature and structure of the body 28, the shackle 26, and the spring-biasing of the lifting hook 30. It can be seen that the lifting hook 30, in FIG. 1, is so oriented that it will snare nothing; it will engage and lift nothing in its open attitude. Spring means (not shown) disclosed in the latter Swedish patent, interposed between the body 28 and the hook 30, holds the hook in the FIG. 1 attitude thereof.
The hoist 20 and the winch 36 are operated to lower the lifting hook 30 into proximity to the bail 16. This is shown in FIG. 2. The winch-connected portion of the material 18 is tensioned, by means of the winch 36, and this overcomes the bias of the aforecited spring means. Consequently, the lifting hook 30 rotates relative to the body 28, and enters and snares the bail 16. Resultantly, lifting can commence by means of the hoist 20. At this time, the body 28 is turned clockwise, relative to the shackle 26, causing a locking function, described in Swedish patent No. 900 1774-0, to be effected. In this locking function, the lifting hook 30 takes a non-turnable, fixed position relative to the body 28. The locked disposition remains until the shackle 26 has been turned in an opposite direction relative to the body 28.
FIG. 3 shows the novel handling means during the lifting of the pump 12. The lifting hook 30 is locked in its bail-engaged disposition, defining a very secure connection to the load. The hoist 20 takes up chain 22 and the load while the winch 36 takes up material 18. Means not shown takes up the cabling 14.
When servicing of the pump 12 is completed, and the latter has to be returned to its operating disposition in the station 10, the novel handling means is employed again. During lowering of the serviced pump 12 into the station 10, the several components and parts take the dispositions shown in FIG. 3.
FIG. 4 represents the disengagement of the lifting hook 30 from the bail 16, upon the pump 12 having been set down in the station 10. The shackle 26 is turned by gravity clockwise relative to the body 28. This releases the aforesaid locking function so that the lifting hook 30 can be turned counter-clockwise and disengage from the bail 16. The winch 36 is operated to provide an adequate slack in the associated portion of the filamentary material 18, and the cited spring biasing, between the body 28 and the hook 30, causes the hook 30 to rotate, as noted, to its horizontal or open attitude.
Now, as shown in FIG. 5, the novel handling means can be raised again, above the pump 12, for a storage disposition until it is needed again. Upon the hoist 20 and the winch 36 raising the handling means to the top of the station 10, the end 32 of the filamentary material 18 can be disengaged from the hook 30 and set at a station mounting 42, and the end 34 can be disconnected from the winch 36 and set at a mounting 44.
FIG. 6 outlines the steps comprised by the novel method of handling a submersible equipment, such as pump 12, namely: penetrating the lifting bail 16 of the equipment with a length of non-corroding, filamentary material 18; suspending a lifting hook 30; coupling one end 32 of the filamentary material to the hook 30; moving the hook into proximity with the bail 16; and pulling a second end 34 of the filamentary material to cause the hook 30 to snare the bail 16.
While I have described my invention in connection with a specific embodiment thereof, and particular steps of procedure, it is to be clearly understood that this is done only by way of example, and not as a limitation to the scope of the invention as set forth in the objects thereof and in the appended claims.
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A length of non-corroding, filamentary material penetrates a lifting bail of the submersible equipment, and one end of the material is coupled to a hook, while the opposite end is pulled to cause the hook to snare the bail. The hook is held in suspension, but moved into proximity to the bail to enable the material to be drawn through the bail, and to cause the hook to engage the bail for sub sequent lifting of the equipment.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional Patent Application No. 60/603,610, which was filed Aug. 23, 2004 and which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] This invention is directed generally to forming anti-microbial materials, and more particularly to forming foam materials having anti-microbial activity and/or filtration properties.
BACKGROUND
[0003] There are several prior art methods that describe metallizing of foam substrates (e.g., Pat. Nos. 6,395,402; 5,151,222; 3,661,597). Different methods have been used to metallize foam for various applications such as EMI shielding etc. Pat. No. 6,395,402 discuss the metallization of copper/nickel for EMI applications. While the adhesion of the metal to the foam may be good, the process cannot produce a good silver coating due to the difference in deposition rates of copper versus silver. In addition, these materials do not provide any-microbial activity as copper/nickel do not provide anti-microbial properties. The other patents listed produce rigid foam that cannot be used in a medical/anti-microbial application(s) or as a flexible filter.
[0004] Accordingly, what is needed is a method of metallizing foam that is capable of using silver. Also what is needed is a method of forming a foam material that has anti-microbial activity. Additionally what is needed is a method of forming a foam material that may be used as a filter and having anti-microbial activity.
SUMMARY OF THE INVENTION
[0005] The present invention provides a method of metallizing a foam material. The method may be used to form a foam material having anti-microbial activity by metallizing the foam with a metal, such as silver. The resulting foam may be used in a variety of different applications such as a filter material. The methods of the present invention are simpler than prior art methods since the foam materials may be metallized without the need for an activation/seeding step. The resulting foam may also be designed such that the product has a low resistance and/or an optimal metal ion release. The method of the present invention uses one or more of the steps of etching the foam, pre-metallizing the foam and metallizing the foam with silver. Depending on the selected properties of the final foam, the method may use some or all of these steps.
[0006] These and other embodiments are described in more detail below.
DETAILED DESCRIPTION OF THE INVENTION
[0007] The present invention is more particularly described in the following description and examples that are intended to be illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. As used in the specification and in the claims, the singular form “a,” “an,” and “the” may include plural referents unless the context clearly dictates otherwise. Also, as used in the specification and in the claims, the term “comprising” may include the embodiments “consisting of” and “consisting essentially of.”
[0008] The present invention provides a method of metallizing a foam material. The method may be used to form a foam material having anti-microbial activity by metallizing the foam with a metal that provides anti-microbial activity to a material. The resulting foam may be used in a variety of different applications that may benefit from a material having anti-microbial activity including, but not limited to, the use of the metallized foam as a filter material. The methods of the present invention are simpler than prior art methods because the foam materials may be metallized without an activation/seeding step commonly associated with prior art methods. The resulting metallized foam materials are formed such that the metal adheres well to the foam. The resulting foam may be designed such that the product has a low resistance and/or an optimized silver ion release.
[0009] The methods of the present invention are designed to metallize foam without the need for an activator. As such, the methods of the present invention are capable of metallizing the film through one or more of the steps of etching the foam, pre-metallizing the foam and/or metallizing the foam with the selected metal. Depending on the selected properties of the final foam, one or more of these steps may be omitted while still achieving a metallized foam product. As used herein, an “etchant” is a material capable of etching or removing portions of the foam material to permit better adhesion of the metal to the foam substrate to be metallized.
[0010] Accordingly, in a first aspect, the methods of the present invention etch the foam to increase the surface area of the foam. To etch the foam, the foam substrate is first quenched using an etchant and then rinsed. The etchant may be, in one embodiment, a base solution. The type of base solution may be any base solution capable of removing or etching portions of the foam substrate. The type of base solution that may be used may vary depending on one or more factors including, but not limited to, the foam substrate to be etched, the metal to be applied, the degree of etching desired, and/or the final characteristics of the metallized foam. Examples of base solutions that may be used for the etchant include, but are not limited to, alkaline hydroxides, such as lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, francium hydroxide, beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, or a combination thereof. In one embodiment, the base solution is sodium hydroxide.
[0011] The foam may be etched by immersing the foam substrate in a solution containing the etchant. As used herein; “immersed” is meant to include any method by which a solution may be contacted with at least a portion of a surface area of a foam substrate including, but not limited to, dipping, spraying, immersing, quenching, and/or any other method capable of applying a liquid to at least a portion of a substrate.
[0012] In one embodiment, the first step in the process may be performed either immediately prior to the second step or may be performed as a preparation step with subsequent steps taking place at a future time. As such, thicker foams and/or extended amounts of foam may be treated in a mass processing step. This would enable a manufacturer to quench thick foam (1′ thick) and 12 feet or more of length at a time. Alternatively, flame-treated non-etched foam may be etched in-house using a stronger solution of sodium hydroxide.
[0013] The first etching step may be performed under a range of operating temperatures and/or dwell or etch times, depending on the type of foam to be etched, the etchant used, and/or the selected characteristics of the finished product. Various embodiments for the methods of the present invention are set forth below, although it is to be understood that other embodiments are also included within the scope of the present invention. For the percentage of the foam that is etched:
Etching % First Embodiment 3-75 Second Embodiment 10-50 Third Embodiment 15-40 Fourth Embodiment ˜25
[0014] For the temperature at which the process is to be operated:
Temperature range ° C. First Embodiment 10-60 Second Embodiment 15-50 Third Embodiment 20-40 Fourth Embodiment ˜30
[0015] For the etch time of the process:
Etch Time in Minutes First Embodiment 1-45 Second Embodiment 10-30 Third Embodiment 15-30 Fourth Embodiment ˜25
[0016] The temperature and time of etch may be dependent on the concentration of the etchant solution.
[0017] After the foam has been etched, the foam may be conditioned with a non-ionic surfactant or other suitable material to enable the surface to be wet out and/or to clean the surface of any debris/dirt. A good rinsing process using de-ionized water with temperature under 70° C. follows may be used with the following embodiments:
Temperature of DI Water First Embodiment 5-70 Second Embodiment 10-50 Third Embodiment 20-40 Fourth Embodiment ˜30
[0018] Some polyether foams may not be etched since the chemistry as described below is sufficient to activate the surface of the foam material. As a result, for the methods of the present invention, when a polyether foam is used as the foam substrate, the foams may be metallized without the need for an activation/seeding step or an etching step for preparing the foam for metallization.
[0019] After the step of etching the foam, then the methods of the present invention may include a pre-metallization step. The pre-metallization step is utilized to prepare the foam for the application of the metal and to help facilitate attachment of the metal to the foam substrate. In one embodiment, the pre-metallization step may be accomplished by dipping the etched foam in an acid solution. An acid dip, such as with HCl, may then be used. The acid dip acts as a pre-metallizing step utilizing the acid as the solvent. Other acids, such as sulfuric acid or nitric acid, may be used for the pre-metallization step. A rinsing step may then be used upon completion of the pre-metallizing step.
[0020] For the dwell times of the pre-metallizing step, various embodiments are set forth below:
Dwell Time in acid (minutes) First Embodiment 1-35 Second Embodiment 3-30 Third Embodiment 5-20 Fourth Embodiment ˜15
[0021] For the concentration of the acid in the pre-metallizing step, various embodiments include:
Concentration of acid (%) First Embodiment 0.5-35 Second Embodiment 1-20 Third Embodiment 3-18 Fourth Embodiment ˜15
[0022] The pre-metallization step may, in one embodiment, provide a mixture of stannous chloride and muriatic acid. The amount of stannous chloride may be, in one embodiment, selected to be between about 60 gm/l up to about 140 gm/l and the concentration of the muriatic acid may be between about 6 to about 15%. The dwell time may be selected to be between about 3 and 15 minutes. Once the pre-metallization step is completed, the process may be followed by a special counter flow rinsing with controlled water flow. This step enables the acid to remove any excess salts and acids from the substrates yet leave an optimum amount of activators on the surface. For the concentration of the muriatic acid, various embodiments are set forth below:
Concentration of acid (%) First Embodiment 4-25 Second Embodiment 5-20 Third Embodiment 8-18 Fourth Embodiment ˜10
[0023] For the concentration of the stannous chloride, various embodiments are set forth below:
Concentration of Stannous Chloride First Embodiment 5-40 Second Embodiment 10-30 Third Embodiment 20-25 Fourth Embodiment ˜10
[0024] For the dwell time, various embodiments for the present invention may include:
Dwell time in minutes First Embodiment 5-60 Second Embodiment 10-50 Third Embodiment 20-30 Fourth Embodiment ˜10
[0025] It is to be understood that embodiments for the concentration of the acid, the concentration of the stannous chloride and/or the dwell time are not required to be used in the order listed above in the respective tables, but may be used in any order or combination thereof. Accordingly, in one embodiment, the concentration of the acid may be from about 5 to about 20%, the concentration of the stannous chloride may be about 10%, and the dwell time may be from about 5 to about 60 minutes. Alternatively, in another embodiment, the concentration of the acid may be from about 8 to about 18%, the concentration of the stannous chloride may be from about 5 to about 40%, and the dwell time may be from about 10 to about 50 minutes.
[0026] Once the foam has been prepared, the methods of the present invention then include a final step of applying the metal to the foam. The step may be referred to as a metallization step. The metallization step may be performed using known metallization technologies such as those described in Pat. No. 3,877,965 or patent application Ser. No. 10/666,568, which are hereby incorporated by reference.
[0027] The metallized foam may then be placed in an oven at 60-70° C. for about 30 minutes to produce a semi-quenching effect to help attach the metal to the foam.
[0028] The methods of the present invention may be used with a variety of different metals that may be desired to be attached to a foam substrate. In one embodiment, the metal is silver. Silver provides anti-microbial, conductive and/or anti-static properties to the foam substrate. In alternative embodiments, the metal may be selected from copper, gold, aluminum, or any other metal capable of being attached to a foam substrate.
[0029] The present invention may be used with any type of foam. Examples of foams that may be used include, but are not limited to, polyurethane, polyester, polyether, or a combination thereof. The resulting foams have enhanced resistance (ohms/square), anti-microbial activity, ion release, or a combination thereof, as compared to prior art foams.
[0030] The metallized foam products made according to the methods of the present invention may be used in any application wherein the advantages offered by the metal may be utilized. For example, due to the anti-microbial benefits, if the metal is silver, the metallized foam may be used as a filter material for the filtration of liquids. In addition, the foam may be in the form of a thin layer, such that the resulting metallized foam may be used as a wrap for wounds to assist in healing of the wounds.
[0031] The present invention will now be further described through examples. It is to be understood that these examples are non-limiting and are presented to provide a better understanding of various embodiments of the present invention.
EXAMPLES
Example 1
[0032] A bath was prepared by dissolving 4.2 gm of silver nitrate in de-ionized water. It was then complexed with 3.3 ml of 27% aqua ammonia. A quenched foam sample weighing 24.0 gm was cleaned with non-ionic surfactant such as Triton X-100 and rinsed thoroughly. Foam was etched with 15% HCl for 20 minutes. The foam was then pre-metallized with solution having 10% HCl and 10 gm/l of anhydrous tin chloride for 20 minutes. The foam was then rinsed in counter flow de-ionized water. 0.63 gm of tetra sodium EDTA was dissolved in 2 liters of de-ionized water. 6.5 ml of NEL/AEM surfactant was also added to the bath. The foam was placed in the reactor and solution was agitated. Silver complex was added and then 1.8 ml of formaldehyde was added. After three hours the sample was removed and subjected to hot water rinse. Then a 0.2% NaOH solution was (50 mL volume) was made up and at 60° C. The metallized foam was then dipped into the solution. The color changed to a gold tone.
Example 2
[0033] The sample obtained from example 1 cut to produce a 1.5 gm sample. This was then placed in a beaker with 5% sodium chloride solution for 24-hour period at 37° C. The solution after 1-hour period was then tested for silver ions using a Perkin Elmer Analyst 300. The ion release was 0.5 ppm
Example 3
[0034] The sample obtained from example 1 was cut to weight 0.75 gm and was subjected to Dow Corning Corporate Test Method 0923 and/or ASTM-E2149 Test method. The organism used was Staphylococcus aureus ATCC 6538. The reduction of organism growth was over 99.9%.
Example 4
[0035] The Sample obtained from example 1 was subject to process similar to the one described in U.S. patent application Ser. No. 10/836,530, the disclosure of which is hereby incorporated by reference in its entirety. This sample was then subjected to the ion release protocol as described in example 2. The ion release was at 6.2 ppm in one hour
Example 5
[0036] The sample obtained from example 1 was subject to ASTM E-2149 test for antimicrobial efficacy. The organism used was Staphylococcus aureus ATCC 6538. The reduction of organism growth was over 99.9%.
[0037] The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention.
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A method of producing a metallized polymeric foam that produces an anti-microbial material using an advanced method of metallizing polymeric foam with a metal, such as silver. The foam material may be polyurethane, polyester, polyether, or a combination thereof. The method provides a 3-dimensional surface coating of the metal. The metallized substrate is durable and highly adherent. Such metallized foam is a highly effective filter and/or an anti-microbial product. The mechanism of filtration is mainly due to Vander Der Wal attraction. The anti-microbial activity may be due, in part, to the release of select metal ions as a response to stimuli.
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The United States Government has rights in this invention pursuant to Contract No. DE-AC04-76DP00789 between the Department of Energy and AT&T Technologies, Inc.
BACKGROUND OF THE INVENTION
The present invention relates to an empirical electrical method for remote sensing of steam quality utilizing flow-through grids which allow measurement of the electrical properties of a flowing two-phase mixture.
The measurement of steam quality in the oil field is important to the efficient application of steam assisted recovery of oil. Because of the increased energy content in higher quality steam it is important to maintain the highest possible steam quality at the injection sandface. The effectiveness of a steaming operation without a measure of steam quality downhole close to the point of injection would be difficult to determine. Therefore, a need exists for the remote sensing of steam quality.
A number of methods currently exist for the measurement of steam quality. For example, a December 1981 publication by Sandia National Laboratories, SAND80-7134, contains an article by A. R. Shouman entitled "Steam Quality Measurement: A State of the Art Review". Shouman reviewed existing methods and identified two techniques which could be useful for remote sensing of pure steam, one based on acoustic propagation characteristics of two-phase flow and a second on venturimeters.
Another method is disclosed by H. A. Wong, D.S. Scott, and E. Rhodes in an article "Flow Metering in Horizontal Adiabatic Two-Phase Flows" found in Flow/81: Its Measurement and Control in Science and Industry, Vol. 2, 1981, pp. 505-516. Wong et al. have developed a twisted tape venturimeter for two-phase quality measurements. Although this method has been used for steam quality measurements in the field, no detailed calibration measurements on wet, high pressure steam have been reported.
A venturimeter/orifice plate system has been used successfully (although not downhole) for wet steam quality measurements at up to 980 pounds per square inch (psi) by D. B. Collins and M. Gacesa as described in the March 1971 publication of J. Basic Engineering on pp. 11-21.
Other more recent techniques of steam quality measurement include gamma and x-ray attenuation. In order to be useful however, they require extensive calibration against known standards over the complete range of conditions which may be encountered downhole.
Therefore it is desired to provide an empirical electrical method for the remote sensing of steam quality that can be adapted to downhole steam quality measurement.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an empirical method for the remote sensing of steam quality.
It is another object of the present invention to provide an empirical method for the remote sensing of steam quality that can be easily adapted to downhole steam quality measurements.
It is a further object of the present invention to provide a device for allowing measurement of the electrical properties of two-phase flow in the method of steam quality measurement.
It is a still further object of the present invention to provide a device for allowing measurement of the electrical properties of two-phase flow in the method of steam quality measurement which will not alter the flow characteristics and at the same time be able to withstand an adverse environment.
Briefly described, in accordance with the present invention, an empirical electrical method for the remote sensing of steam quality has been developed. A device is made from special flow-through grids which allow measurement of the electrical properties of a flowing two-phase mixture without interfering with the flow. The effect on the capacitance of the flowing mixture at low frequencies yield a straight line relationship. The device must be calibrated for each specific application, and clearly can be adapted to other applications.
More specifically, the present invention is directed to a method for measuring the quality of steam flowing through a conduit in a downhole oil well system at the injection sandface, the improvement comprising the steps of: calibrating the system by filling a conduit containing two spaced electrodes with steam samples of known qualities; applying an AC signal across the terminals; measuring the capacitance between the electrodes as a function of frequency of the applied signal for each steam sample; and determining a frequency range where measured capacitance is a linear function of steam quality. The calibrated system is then used by injecting an unknown sample of steam into the conduit; applying an AC signal at a selected frequency within the frequency range to the electrodes; measuring the capacitance between the electrodes at the selected frequency; and determining steam quality from the capacitance measurement.
The electrodes may be spaced either longitudinally of the conduit in which case planar electrodes are used or transversely of the conduit in which case cylindrical electrodes are used.
In either case the electrodes are disposed downhole adjacent to the oil well sandface and all capacitance measurements are made remotely above the steam injection zone.
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 plan view of a single planar flow-through electrode a pair of which are utilized to measure the steam quality in accordance with the present invention;
FIG. 2 is a side elevational view partially in section illustrating three flow-through electrodes of the type illustrated in FIG. 1 mounted in a pipe for measurement of electrical and thermal properties of steam flowing therethrough;
FIG. 3 is a diagrammatic view of a portion of a flow system including a cooler bath, a conventional enthalpy tank for measuring steam quality, and an input to an analyzer and signal source;
FIG. 4 is a diagrammatic view of the laboratory apparatus utilized for measuring steam quality with the standard calorimeter techniques of the enthalpy tank of FIG. 3 and the electrical properties using the electrodes of FIG. 2 for developing the empirical data to be utilized in the downhole steam quality measurement method of the present invention;
FIG. 5 is a diagrammatic view of a data analyzing and recording system for the steam quality and electrical parameters measured by the system of FIG. 4;
FIG. 6 is a graph showing a correlation of steam quality with the measured capacitance between a pair of electrodes of FIG. 2 having capacitance at a low frequency voltage signal (20 Hz) applied therebetween;
FIG. 7 is a graph showing a correlation of steam quality with the measured capacitance between a pair of electrodes of FIG. 2 with a high frequency voltage signal (2000 Hz) applied therebetween;
FIG. 8 is a graph illustrating the substantially linear relationship between capacitance and steam quality between a voltage signal frequency range of about 20 to 200 Hz, as determined by the empirical data generated by the system of FIG. 4; and
FIG. 9 is an alternative embodiment of cylindrical electrodes spaced transversely of a conduit through which steam is flowing at a downhole location.
DETAILED DESCRIPTION OF THE INVENTION
Referring in detail to FIG. 1 there is illustrated a single flow-through electrode 10 for measurement of electrical and thermal properties of steam flowing therethrough. As will become more readily apparent hereinafter a spaced pair of such electrodes will be utilized in accordance with the present invention to measure steam quality downhole near the sandface of an oil well.
Each electrode 10 is made using a computer-generated rectangular grid pattern 12 of 0.51 mm wires 14 on a 6 mm grid space 16 surrounded by a 25 mm outer annulus 18 of a 3 mm width. A tab 20 extends from the outer annulus 18. This computer-generated pattern is photo etched onto 0.13 mm 304 stainless steel resulting in a physical electrode having parts corresponding to those computer-generated parts described hereinabove.
Electrodes 10 are plated with Wood's nickel strike to a thickness of about 0.0025 to 0.005 mm and then with about 0.0025 to 0.0037 mm of gold on top of the nickel by the Englehart technique. Electrical connection to the electrode 10 is made with 2.18 mm chromel/alumel, stainless steel sheath thermocouple wires 22 with the ball spot welded to the electrode 10 at a point 24. The sheath 22 is sealed with RE-X glass ceramic 26 at one end of a bidirectional sleeve 28 mounted in a perpendicular arrangement on tab 20.
The RE-X glass ceramic 26 was developed by General Electric for high voltage insulators and has a coefficient of expansion closely matched to chromel/alumel resulting in a good glass to metal seal. RE-X glass ceramic 26 is workable at 950° C. but will withstand a continuous temperature of 830° C. without degradation rendering it highly suitable for application in downhole steam measurement. This glass ceramic 26 has a weathering resistance better than glass and as good as glazed porcelain.
At the sleeve 28 end opposite that of the ceramic seal 26 are electrode leads 30 to be coupled to an impedance analyzer and thermocouple readout provided in the data recording system of FIG. 5 to be described hereinafter.
Referring to FIG. 2 there is illustrated a side elevational view partially in section of an electrical grid system of a plurality of spaced flow-through electrodes 10 for measurement of electrical and thermal properties of steam flowing through a conduit or tube 32. The tube 32 is disposed in the laboratory system of FIG. 4 to be described hereinafter.
Three electrodes 10 are mounted in a 50 mm ID pyrex T-tube 32 having flanged ends 34a, b and c with gaskets 36a, b and c mounted to each respective flanged end 34a, b and c by any suitable attachment means such as bolts 38(a-f). The three electrodes 10 are held in place by phenolic (laminated sheet cloth fabric base) spacers 40 with a 50 mm outer diameter and a 25 mm inner diameter. These spacers 40 are arranged such that the distance between each adjacent electrode 10 is 12 mm.
Leads 30 from the electrodes 10 and thermocouples 22 are fed out through the right angle section of the pyrex T-tube 32 to a junction box 42 (see FIG. 4). The junction box 42 serves as the branching off area whereby it is possible to measure either temperature through the thermocouples 22 of each electrode 10 or electrical parameters through just one lead 30 of each thermocouple 22. Use of this junction box 42 is useful to prevent interference between temperature measurements and measurements of electrical parameters.
FIG. 3 illustrates a portion of a flow system including conventional enthalpy tank 50 utilized in the laboratory system of FIG. 4 to be described hereinafter for measuring steam quality using standard condensing calorimeter techniques.
An enthalpy tank 50 is made by forming a coil 52 of 10 mm copper inside a container 54. Steam is passed through the coil 52 and allowed to exit through a perforated cylinder 56 at the end of the coil 52 and into water 58. The initial column of water 58 should be chosen to cover both the coil 52 and exit cylinder 56. A stirring magnet 60 located on the bottom of the enthalpy tank 50 is activated by a stirrer motor 62 and subsequently keeps the water 58 well mixed.
A small change in temperature (ΔT) of the water is used to measure the initial and final mass and temperature of the water over a range of 30° C. in order to reduce evaporative losses as much as possible. The container 54 is insulated by insulation blanket 64 to minimize heat loss and thermal variations.
The actual calculation of steam quality X is a result of the equation: ##EQU1## where h f is the enthalpy of saturated liquid, h fg is the change in enthalpy between a saturated liquid and a saturated vapor, and h is the measured enthalpy. Values for h f and h fg are taken from standard tables for the measured values of the steam temperature and/or pressure.
All measured quantities are for the appropriate systems in equilibrium. For instance, after the steam is turned off to the enthalpy tank 50, the copper coil 52 is disconnected from the rest of the system and the water bath 58 is stirred until the enthalpy tank has come to thermal equilibrium.
FIG. 4 illustrates a laboratory apparatus and method for developing the empirical data required for measuring downhole steam quality utilizing standard calorimeter techniques with enthalpy tank 50 of FIG. 3 and the flow-through electrode grid structures 10 of FIGS. 1 and 2.
In utilizing this laboratory procedure, the steam quality is measured first with enthalpy tank 50 followed by electrical parameter measurements with electrodes 10 in tube 32.
Plant steam is generated by suitable means, dispensed through a cooler bath having cooling coils 68 used to vary steam quality, then the steam quality is measured first in the enthalpy tank 50 as previously described. Measurements from this enthalpy tank 50 may be fed through lead lines 66 a and b to data logger 44 shown in FIG. 5. After steam quality has been measured in this manner, the steam is then diverted to an experimental vessel 70 containing the pyrex T-tube 32, having flow through electrodes 10 therein. Electrode leads 1, 2 and 3 are fed to the junction box 42.
In every case, the electrode grid system enclosed in the pyrex T-tube 32 is kept at steam temperature by temperature controlled heat tape wrapped around the tube chamber after which the whole chamber is wrapped in insulation. This combination is generally indicated as a heater 72 and is kept at steam temperature by a heater control 74. Various valves V, gauges G and drains D complement the system described. After the electrode chamber in T-tube 32 reaches equilibrium, electrical measurements may be made between each adjacent pair of electrodes, with the data being averaged.
FIG. 5 illustrates a view of a detecting and recording system for the data generated in the laboratory system of FIG. 4.
Temperature measurements are obtained through the thermocouples 22 using a data-logger 44, and electrical parameters are measured through one lead 30 of each thermocouple 22 using an impedance analyzer 46. In measuring the impedance, an operator switches the junction box 42 to scan successive pairs of electrode leads 30 which are input into the junction box 42. Automated data recording is done at 5, 10, 20, 50, 100, 200, 500, 1000, 2000 and 5000 Hertz (Hz) of the parallel capacitance and conductance between each set of electrodes 10 being scanned. At each frequency, a series of measurements is made and averaged, then these data are fed into a computer 48. All data is analyzed by the computer 48 to determine whether computer transfer errors have occurred and corrective measurements are made as needed. Intermediate results may be printed for each frequency, and when measurements have been made over the entire range of frequencies, all accumulated data is stored on magnetic tape for later analysis.
Lead lines 66 a and b entering into data logger 44 serve to transfer data obtained from standard condensing calorimeter techniques as described with respect to FIG. 3. Results from the standard condensing calorimeter technique are used as a basis of comparison to validate the accuracy of the steam quality measurements using the electrical parameters (capacitance) of the flow through electrode grids.
FIG. 6 is a graph showing actual test results correlating steam quality with capacitance between electrodes 1 and 2 at low frequencies (20 Hz) of voltage signals applied therebetween. This proves to be a straight line (linear) relationship, indicating that capacitance measurements using the flow through grid process at low frequencies will yield accurate and easily interpretable steam quality information.
FIG. 7 is a graph showing actual test results correlating steam quality with capacitance between electrodes 1 and 2 at high frequencies (2000 Hz) of voltage signals applied therebetween. The non-linear relationship illustrated makes measurements using the flow-through grid system at high frequencies difficult to predict and may result in erroneous projections of steam quality at the sandface.
FIG. 8 is a graph illustrating the test results of the laboratory system of FIG. 4 over a wide frequency range of voltage signals applied between electrodes 1 and 2. the results show a substantially linear relationship of steam quality curves between frequency and capacitance in the frequency range from about 20Hz to 200Hz. Thus, the test results show that steam quality can be accurately measured as a function of the capacitance between spaced flow-through electrodes over a frequency range of 20 Hz to 200 Hz.
A variation in the geometry of the flow through electrodes previously described could be two concentric cylinders E1,E2 made of a similar wire mesh as in the electrodes 10 illustrated in FIG. 9. Electrodes E1,E2 are mounted such that their center lines are also on the center line of the steam injection string pipe P. Additional information may be obtained from this arrangement such as if any steam has condensed and is on the outer walls of the tubing. This could be measured by obtaining the capacitance M between the outer electrode E1 and the pipe P. The capacitance C between E1 and E2 is measured to determine steam quality.
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.
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An empirical method for the remote sensing of steam quality that can be easily adapted to downhole steam quality measurements by measuring the electrical properties of two-phase flow across electrode grids at low frequencies.
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BACKGROUND OF THE INVENTION
This invention relates to apparatus for determining the angular position of a rotatable device, shaft or the like.
There are numerous types of devices for measuring the angular position of a shaft or the like. Such devices sometimes referred to as shaft angle encoders oftentimes utilize a light source or sources, photo detectors, and some kind of "coded" card which moves between the light sources and photo detectors as the shaft whose angle is to be measured is rotated. As the card is moved, various light patterns are detected by the photo detectors to indicate angular position of the shaft.
The coded card is oftentimes formed into a drum and mounted on the shaft to rotate therewith. The light source (or the photo detectors) is positioned inside the drum with the photo detectors (or light source) being positioned outside the drum. Examples of shaft angle encoders which utilize such a drum or cylinder configuration are described in U.S. Pat. Nos. 3,714,448; 3,731,107; 3,742,486 and 3,770,970. One of the drawbacks with this drum-type configuration is the spatial problem of conveniently positioning the necessary components inside and outside of the drum. Such positioning may be quite awkward, especially since the shaft whose angle is to be determined will be associated with some equipment which must be accounted for in locating the shaft angle encoder equipment.
Another arrangement oftentimes used with the coded card is to provide a disc mounted on the shaft whose angle is to be determined, locate or code a plurality of openings in the disc, and position a light source or sources on one side of the disc and photo detectors on the other side. Examples of this type of arrangement are described in U.S. Pat. No. 3,234,394 and 3,381,288. Again, with this type configuration, it is oftentimes difficult to conveniently position the shaft angle encoder equipment so as not to interfere with the equipment associated with the shaft.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a simple and inexpensive angular position measuring arrangement having few component parts.
It is another object of the present invention to provide such an arrangement in which most of the component parts thereof may be positioned at substantial distances and out of the way of the shaft whose angular position is to be determined.
The above and other objects of the present invention are realized in a specific illustrative embodiment which includes a prism coupled to rotate with a shaft whose angular position is to be determined, a light beam source for detecting a light beam onto the prism to pass therethrough, and an array of photo detectors positioned to intercept the light beam passing through the prism. The prism is formed to refract the beam of light and to direct the light onto different ones of the photo detectors as the prism, and thus the shaft, is rotated. The particular photo detector onto which the beam of light impinges determines the angular position of the shaft.
In another embodiment of the invention, the prism is provided with reflective surfaces to direct the beam of light in directions other than those in which the refracted beam is directed to enable measuring the angular position of the shaft through a greater angular displacement thereof.
BRIEF DESCRIPTION OF THE DRAWING
The above and other objects, features and advantages of the present invention will become apparent from a consideration of the following detailed description presented in connection with the accompanying drawings in which:
FIG. 1 is a perspective view of angular position measuring apparatus made in accordance with the present invention;
FIG. 2 is an end view of the shaft and prism of FIG. 1; and
FIGS. 3A, 3B, and 3C are end views of an alternative embodiment of the invention which includes a prism having both refractive and reflective surfaces.
DETAILED DESCRIPTION
Referring to FIG. 1, there is shown the basic components of one embodiment of the present invention. In this embodiment, a semicylindrical prism 2 is mounted on the end of a shaft 6 whose angular position is to be determined. A light source 10 directs a narrow beam of light 14 onto a curved side 2a of the prism, and this beam passes through the prism and exits from a flat side 2b. The light beam source 10 is maintained in a fixed position relative to the prism 2 and shaft 6 and utilizes well known methods for producing the narrow light beam. This could be done for example using a combination of focusing lenses and a lamp.
A series array of photo detectors 18 is positioned in an arced configuration on the side of the prism 2 opposite the light beam source 10. The photo detector array 18 may consist of any of a variety of photo responsive elements such as photo transistors, photo resistors, etc., which exhibit some electrical parametric change depending upon the presence or absence of a light falling on the element. A photo transistor, for example, is a light sensitive solid state device which either allows passage of current or prevents passage of current therethrough when exposed to light. When the light beam passing through the prism 2 falls on a particular one of the photo detectors in the array 18, that photo detector applies an electrical signal to utilization apparatus 22.
The prism 2 is mounted on the shaft 6, as generally shown in FIG. 2, so that as the shaft 6 is rotated, the light beam 14 will enter the prism normal to the curved surface 2a. This can be done by mounting the prism 2 to rotate about the center of curvature 24 of the curved side 2a. With the beam 14 entering the prism 2 normal to the surface 2a, no refraction of the beam at that surface takes place. The beam of light 14 passes through the prism 2 and exits from the flat side 2b of the prism and is there refracted to impinge on one of the photo detectors of the array 18. As the shaft 6, and thus prism 2, are rotated, the direction of the refracted beam is caused to move to impinge on successive ones of the photo detectors of the array 18. In particular, as the prism 2 is rotated in the counterclockwise direction, the refracted beam moves in the clockwise direction along the array 18 and as the prism 2 is caused to move in a clockwise direction, the refracted beam is caused to move in a counterclockwise direction.
The particular angle at which the refracted beams exits from the flat surface 2b of the prism can be determined by the well known Snell's Law. Since the exit angle of the refracted beam can be determined as a function of the angular position of the prism 2, the particular photo detector of the array 18 on which the refracted beam falls determines the angular position of the shaft 6. The signal applied by the particular photo detector to the utilization apparatus 22 thus indicates to the utilization apparatus the angular position of the shaft 6.
The utilization apparatus 22 might illustratively use the information supplied from the photo detector array 18 to provide some type of visual readout specifying the angular position of the shaft or to perform some computation in which the angular position of the shaft is of importance, etc.
It will be noted that with the FIGS. 1 and 2 structure, the angular position of the shaft 6 may be determined as the shaft rotates through some predetermined angular displacement less than 180°. The range of angular positions of the shaft 6 which may be measured is determined by the index of refraction of the prism 2 and specifically by the so-called critical angle of the prism (the angle of incidence of a beam of light on an interface at which no refracted ray exists). For a prism having an index of refraction of 1.5, the "critical angle" for a light beam in the prism striking a prism/air interface is about 40 degrees so that refraction will occur only through an angular displacement of the prism of about 80° (i.e., through rotation of the prism from an angle of incidence of about 40° on one side of the normal of the refractive interface to about 40° on the other side of the normal). Outside of this 80° range no refraction occurs and so, of course, no signal would be generated by photo detectors. It should also be noted that as such a prism is rotated through the 80° range, the refracted ray moves through an angular displacement of about 75°. This can be verified by applying Snell's Law to a prism of the type shown in FIGS. 1 and 2 and assuming that the index of refraction of the prism is 1.5.
The prism configuration shown in FIGS. 3A through 3C enable determining the angular position of a shaft through a greater angular displacement that can be done with the FIGS. 1 and 2 configuration. In the FIGS. 3A through 3C prism configuration, a four-sided prism 30 is provided with one side 30a being curved about a center of curvature 34, an opposite side 30b being substantially flat, and the two other sides 30c and 30d also being substantially flat and having silvered (or other reflective material) surfaces to reflect light impinging thereon. The four sides of the prism 30 might illustratively be oriented relative to each other in such a manner as to privide for a continuous readout from the photo detector array 44 as the prism is rotated through some predetermined angular displacement. That is, as the prism 30 is rotated through some predetermined range, the incident light beam 36 is either refracted or reflected onto the photo detector array 44 to provide an indication of the angular position of the prism and thus of the shaft on which it is mounted. This can best be understood by describing an exemplary range of movement of the prism 30 as shown in FIGS. 3A through 3C.
Assume that the prism 30 is positioned so that the incident beam of light 36 enters the prism through the curved surface 30a. In such a case, the beam travels through the prism 30 and is refracted at the surface 30b of the prism to impinge on one of the photo detectors in a range of the photo detector array 44 indicated by the arrow 40. When the prism is positioned in this manner, the light beam is refracted as previously described for the configuration of FIGS. 1 and 2. Assume now that the prism 30 is rotated in a clockwise direction to a point where the incident beam of light 36 strikes the reflective surface 30c of the prism. When this occurs, the light beam, of course, is no longer refracted but rather is reflected from the surface 30c to strike the photo detector array 44 somewhere in the range indicated by arrow 48 (See FIGS. 3B and 3C).
To avoid an ambiguous readout, the reflective surface 30c must be oriented with respect to the curved surface 30a such that the light reflected from the surface 30c will impinge on photo detectors different from those on which the refracted beam inpinges. To provide a continuous readout as the prism is rotated as indicated in FIGS. 3A and 3B, the photo detectors on which the reflected beam are to impinge must be positioned so that just as the prism 30 is rotated to position where the light beam 36 begins to strike the reflective surface 30c, the resulting reflected light beam will strike a photo detector in range 48. With the configuration shown in FIGS. 3A through 3C, the photo detector in question would be the photo detector indicated at 48a. Then, as the prism 30 were rotated further in the clockwise direction, the reflected beam would impinge on successive ones of the photo detectors in the range 48. When the prism 30 is rotated to a position in which the surface 30c is out of the line of travel of the beam 36, then, of course, no reflection occurs from surface 30c. The position of the prism 30 just before this would occur is shown in FIG. 3C. As can there be seen, the incident beam of light 36 strikes the prism at the reflective surface 30c very near the intersection of the surfaces 30c and 30b. It can be visualized that if the prism 30 were rotated in the clockwise direction a few more degrees, the incident beam 36 would strike the surface 30b and not the reflective surface 30c.
If the prism 30 of FIGS. 3A through 3C were rotated in the counterclockwise direction beginning from the position shown in FIG. 3A, it can be visualized that eventually the incident beam of light 36 would fall upon the reflective surface 30d causing a reflected beam to impinge on one of the photo detectors in the range designated by the arrow 52. In the manner described, a readout would be provided through an angular displacement by the prism 30 of about 180°, i.e., through a range beginning at the position in which the incident beam of light 36 strikes the reflective surface 30c very near the intersection of that surface with the surface 30b and ending at the position in which the incident beam of light 36 strikes the surface 30d very near the intersection of that surface with the surface 30b.
It can be appreciated that various arrangements using refractive and reflective surfaces on a prism body could be provided for giving a readout specifying shaft position. For example, the prism of FIGS. 3A through 3C might be provided with a one-way reflective surface at surface 30b so that a light beam striking the surface from a direction within the prism is refracted, but a light beam striking the surface from a direction without the prism is reflected. In such a case, a readout through a 360 degree rotation of the prism could be achieved.
It is to be understood that still other embodiments could be devised by those skilled in the art without departing from the spirit and scope of the invention, and the appended claims are intended to cover such other embodiments.
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Angular position measuring apparatus includes a prism mounted on a shaft whose angular position is to be determined, and a light source for directing a beam of light onto the prism. The prism is formed so that the light beam enters one surface of the prism and is refracted by another surface and caused to be directed in different directions as the prism, and thus the shaft, is rotated. Also included is an array of photo detectors positioned so that the refracted light impinges on various ones of the photo detectors depending upon the angular position of the shaft. The photo detector on which the light impinges is thereby caused to generate an electrical signal which is applied to utilization apparatus.
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FIELD OF THE INVENTION
[0001] The invention relates to a system and method for interaction between users, particularly users of an online community, such as a social network. More generally, the system and method automatically discovers potential relationships which may facilitate more interaction between users.
BACKGROUND OF THE INVENTION
[0002] Online communities, such as social networking sites, continue to grow in popularity as they allow participants to safely interact with other participants in a virtual environment. However, the potential for interaction between the various participants may not be readily apparent, and this may limit the actual interactions that take place between the participants. Some prior art solutions have attempted to define potential relationships between individuals. However, this has been based on limited analysis of user activity or self-identification through surveys, resulting in mapping of only simple connections between users.
SUMMARY OF THE INVENTION
[0003] The present invention relates to a system and method for interaction between users, particularly users of an online community, such as a social network. More generally, the system and method automatically discovers potential relationships which may facilitate more interaction between users. Automatically discovering the potential for increased interaction between users may have significant added value, both in terms of business opportunities for the site operator due to increased usage, and in terms of usefulness and effectiveness of the online social networking site for the users.
[0004] In an embodiment, a system and method in accordance with the present invention automatically generates user-interest profiles for each user of an online community, such as an online social network. The users are classified into different interest groups, and then the potential user relationships are displayed using various linking tools, such as hyperlinks in the case of web page interfaces, for example. The system and method may also gather information about whom and how individual users interact with other users and systems. Unlike conventional data gathering techniques, the system and method in accordance with an embodiment of the present invention clusters keywords in user log data in order to extrapolate and identify interconnections or relationships that may result in potential interactions between users.
[0005] In an aspect, there is provided a method of facilitating interaction between users of an electronic community, comprising: reviewing a user activity log for each user in the electronic community; executing a natural language parser to extract significant noun phrases from the user activity log; updating user profiles from the newly extracted noun phrases, based on their usage frequency and importance value; and storing the updated profiles in a user profile and relationship data base; and executing a similarity based clustering algorithm to cluster user profiles, thereby discovering relationships among users and storing them in a user profile and relationship database.
[0006] In an embodiment, the method further comprises displaying for each user the one or more relationships to which the user is assigned, together with a list of users assigned to the one or more relationships.
[0007] In another embodiment, the method further comprises storing for each user the one or more relationships to which the user is assigned in a user profile and relationship database.
[0008] In another embodiment, the method further comprises displaying the one or more relationships together with a list of users.
[0009] In another embodiment, the method further comprises providing a user interface for modifying the user profile in the user profile and relationship database, such that a user may manually add or remove the keywords and modify the weights of the keywords.
[0010] In another embodiment, the method further comprises: updating the user profiles from user activity logs at regular intervals; re-executing the similarity based clustering algorithm on the updated user profiles at regular intervals; displaying any newly assigned relationships to which the user is assigned, together with a list of users assigned to the newly assigned relationships; and removing any relationships to which the user is no longer assigned.
[0011] In another embodiment, the method further comprises providing a user interface for limiting the number of relationships displayed, and the number of users displayed for each relationship.
[0012] In another aspect, there is provided a system for facilitating interaction between users of an electronic community, comprising: means for reviewing a user activity log for each user in the electronic community; means for executing a natural language parser to extract significant noun phrases from the user activity log; means for updating user profiles from the newly extracted noun phrases, based on their usage frequency and importance value; and storing the updated profiles in a user profile and relationship data base; and means for executing a similarity based clustering algorithm to cluster user profiles, thereby discovering relationships among users and storing them in a user profile and relationship database.
[0013] In an embodiment, the system further comprises means for displaying for each user one or more relationships to which the user is assigned, together with a list of users assigned to the one or more relationships.
[0014] In another embodiment, the system further comprises means for storing for each user the one or more relationships to which the user is assigned in a user profile and relationship database.
[0015] In another embodiment, the system further comprises means for displaying the one or more relationships together with a list of users.
[0016] In another embodiment, the system further comprises means for providing a user interface for modifying the user profile in the user profile and relationship database, such that a user may manually add or remove the keywords and modify the weights of the keywords.
[0017] In another embodiment, the system further comprises: means for updating the user profiles from user activity logs at regular intervals; means for re-executing the similarity based clustering algorithm on the updated user profiles at regular intervals; a display for displaying any newly assigned relationships to which the user is assigned, together with a list of users assigned to the newly assigned relationships; and means for removing any relationships to which the user is no longer assigned.
[0018] In another embodiment, the system further comprises means for providing a user interface for limiting the number of relationships displayed, and the number of users displayed for each relationship.
[0019] In another aspect, there is provided a data processor readable medium storing data processor code that when loaded into a data processor device adapts the device to perform a method of facilitating interaction between users of an electronic community, comprising: code for reviewing a user activity log for each user in the electronic community; code for executing a natural language parser to extract significant noun phrases from the user activity log; code for updating user profiles from the newly extracted noun phrases, based on their usage frequency and importance value; and storing the updated profiles in a user profile and relationship data base; and code for executing a similarity based clustering algorithm to cluster user profiles, therefore discovering relationships among users and storing them in a user profile and relationship database.
[0020] In an embodiment, the data processor readable medium further comprises code for displaying for each user the one or more relationships to which the user is assigned, together with a list of users assigned to the one or more relationships.
[0021] In another embodiment, the data processor readable medium further comprises code for storing for each user the one or more relationships to which the user is assigned in a user profile and relationship database.
[0022] In another embodiment, the data processor readable medium further comprises code for displaying the one or more relationships together with a list of users.
[0023] In another embodiment, the data processor readable medium further comprises code for providing a user interface for modifying the user profile in the user profile and relationship database, such that a user may manually add or remove the keywords and modify the weights of the keywords.
[0024] In another embodiment, the data processor readable medium further comprises: code for updating the user profiles from user activity logs at regular intervals; code for re-executing the similarity based clustering algorithm on the updated user profiles at regular intervals; code for displaying any newly assigned relationships to which the user is assigned, together with a list of users assigned to the newly assigned relationships; and code for removing any relationships to which the user is no longer assigned.
[0025] These and other aspects of the invention will become apparent from the following more particular descriptions of exemplary embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In the figures which illustrate exemplary embodiments of the invention:
[0027] FIG. 1 shows a generic data processing system that may provide a suitable operating environment;
[0028] FIG. 2 shows a schematic block diagram of an illustrative system in accordance with an embodiment;
[0029] FIG. 3 shows an illustrative method in accordance with an embodiment;
[0030] FIG. 4 shows another illustrative method in accordance with an embodiment;
[0031] FIG. 5 shows another illustrative method in accordance with an embodiment; and
[0032] FIG. 6 shows yet another illustrative method in accordance with an embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0033] As noted above, the present invention relates to systems and methods for interactions between users of an online community, such as an online social network.
[0034] The invention may be practiced in various embodiments. A suitably configured data processing system, and associated communications networks, devices, software and firmware may provide a platform for enabling one or more embodiments. By way of example, FIG. 1 shows a generic data processing system 100 that may include a central processing unit (“CPU”) 102 connected to a storage unit 104 and to a random access memory 106 . The CPU 102 may process an operating system 101 , application program 103 , and data 123 . The operating system 101 , application program 103 , and data 123 may be stored in storage unit 104 and loaded into memory 106 , as may be required. An operator 107 may interact with the data processing system 100 using a video display 108 connected by a video interface 105 , and various input/output devices such as a keyboard 110 , mouse 112 , and disk drive 114 connected by an I/O interface 109 . In known manner, the mouse 112 may be configured to control movement of a cursor in the video display 108 , and to operate various graphical user interface (GUI) controls appearing in the video display 108 with a mouse button. The disk drive 114 may be configured to accept data processing system readable media 116 . The data processing system 100 may form part of a network via a network interface 111 , allowing the data processing system 100 to communicate with other suitably configured data processing systems (not shown). The particular configurations shown by way of example in this specification are not meant to be limiting.
[0035] Now referring to FIG. 2 , shown is an illustrative system 200 in accordance with an embodiment. As shown, system 200 may include an activity log server 202 which logs a user's interactions within the system 200 , including the user's interaction with various system modules, and with other users of system 200 . Many kinds of user activities (e.g. email, voicemail, voice conversations, instant messages, and electronically stored files, among others) can be logged, and converted into text format as necessary for the purposes of clustering noun phrases or keywords extracted from user log data, in order to extrapolate and identify potential interconnections or relationships.
[0036] The activity log server 202 may be operatively connected to an intelligent profile updater 204 which may be configured to update the user's profile based on recent user activity, as logged on activity log server 202 . The intelligent profile updater 204 may also be configured to check the user activity logs periodically (e.g. daily, hourly, weekly), and to analyze the user activity logs with the help of a language parsing engine 206 and a digital hierarchical dictionary 212 . A digital hierarchical dictionary, such as WORDNET®, groups noun phrases into sets of cognitive synonyms (“synsets”), each expressing a distinct concept. These synsets are then interlinked into a semantic hierarchical tree by means of conceptual-semantic and lexical relations. The intelligent profile updater 204 may further be operatively connected to a user profile and relationship database 208 . The natural language parsing engine 206 may be used to calculate the meaningfulness of noun phrases or keywords, and to extract meaningful noun phrases or keywords for constructing a user profile. The constructed user profile may then be stored in the user profile and relationship database 208 .
[0037] User profile and relationship database 208 may in turn be operatively connected to a clustering algorithm module 210 which may be used to cluster users into different and possibly overlapping context groups. The clustering algorithm module 210 may also be operatively connected to digital hierarchical dictionary 212 for calculating similarity distances between the noun phrases or keywords.
[0038] Still referring to FIG. 2 , the user profile & relationship database 208 may be operatively connected to a front-end user relationship display 214 which may be adapted to display the relationship between users or user groups. For example, in a web based application interface, these relationships may be shown using hyperlinks. The relationships may also be displayed using various other means, such as graphical connectors linking two or more users. User profile and relationship database 208 may also be operatively connected to a front-end manual profile updater 216 , which may be adapted to allow users to manually update their own profiles and override any potential relationship links calculated and assigned by the system 200 .
[0039] As will be further explained below, in this system 200 , the discovered relationships between users are not static. Rather, the relationships may continue to evolve as the users' interests change over time. New potential relationships may form between users and old relationships may disappear, as explained further below.
[0040] Now referring to FIG. 3 , shown is an illustrative method 300 in accordance with an embodiment. As shown, method 300 begins at block 301 , where the user activities logged in the activity log server 202 are retrieved and input at block 301 for processing.
[0041] Next, method 300 proceeds to block 302 , where method 300 may review each user's end of day user activity log. While a daily review of a user's activity log takes place in this illustrative example, it will be appreciated that various other time periods may also be used for the purposes of analysis, such as weekly, or hourly for example.
[0042] Method 300 may then proceed to block 303 , where method 300 performs a text extraction from the user's activity logs. If the logged activity is not already in a text format (e.g. voicemail and recorded voice conversations), then the logged activity can be converted into suitable text format using various known speech-to-text conversion tools.
[0043] Method 300 may then proceed to block 304 where the text messages, which may have been translated into text from voice or other types of user activity logs, are parsed by a language parsing engine, such as natural language parsing engine 206 of FIG. 2 . In an illustrative embodiment, the natural language processing engine used may be the General Architecture for Text Engineering (GATE) natural language engine.
[0044] Method 300 may then proceed to block 305 , where method 300 may employ the natural language parsing engine 206 to form a noun phrases vector containing 0 to n number of noun phrases.
[0045] Method 300 may then proceed to block 306 , where method 300 may map common names, or names not found in the digital hierarchical dictionary 212 , to dictionary defined noun phrases. For example, if “George Bush” is not in the digital hierarchical dictionary 212 , it may be mapped to a word or phrase in the digital hierarchical dictionary 212 , such as “politics” or “American politics”. The mapped word or phrase, for example, “American politics” may then be used for the keyword analysis. This mapping is provided by human and can be stored in a pure text file or in a database table before hand. It acts like an extension to the digital hierarchical dictionary. It is used in certain situations when the meaning of certain words and idioms are only known to certain audiences. In method 300 , this file or table is searched for locating the similar phrase in the digital hierarchical dictionary.
[0046] Method 300 may then proceed to block 307 , where method 300 may calculate the importance value of each new noun phrase or keyword, and remove the less meaningful ones. As an illustrative example, the importance value of each noun phrase or keyword may be decided by its depth in the semantic hierarchical tree of the online dictionary, WORDNET®. For example, in WORDNET, “bike” has a greater importance value than “vehicle” because bike is a specific type of vehicle, and is therefore more descriptive.
[0047] Method 300 may then proceed to block 308 , where the most important keywords left after block 307 form a keywords vector of 0 to n noun phrases. Method 300 may then proceed to block 309 , where the new keywords vector is applied to update a user profile. All the keywords in a user profile are weighted by their usage frequency by the user and importance value. It could be a brand new keyword that is added to the user profile including the weight of importance value. Or if a keyword is already in the user profile, its weight may be increased by the importance value of the instance of the keyword. The user profile also maintains a feature list, which contains a list of most highly weighted keywords. This feature list is then used by the clustering algorithm for user relationship discovery in method 400 as described further below. The feature list evolves every time the user profile is updated. A more important keyword can be added to the feature list while a less important one is thrown out. This changing feature list affects the relationship discovery process. As described earlier, new potential relationships may form while old relationships may disappear. Method 300 may then loop back to block 301 , and repeat as necessary.
[0048] Now referring to FIG. 4 , shown is a method 400 for generating user-related processes in accordance with an embodiment. Method 400 starts at block 401 for all users. Method 400 then proceeds to block 402 where method 400 processes keywords using a member similarity based clustering algorithm module (e.g. clustering algorithm module 210 ). This clustering module classifies user profiles by using a member importance function and a member similarity function. In the present system, the member importance function is implemented as the depth in the semantic hierarchical tree of a dictionary. The member similarity function is then implemented as the path distance in the semantic hierarchical tree of a dictionary (e.g. digital hierarchical dictionary 212 ). The Clustering algorithm 402 allows the tuning of the clustering parameters for different effects. For example, we may adjust the similarity threshold to fine tune the number of clusters it returns. The bigger the similarity threshold, the less number of clusters (relationships); The smaller the similarity threshold, the more number of clusters (relationships).
[0049] Method 400 then proceeds to block 403 , where method 400 generates a list of interconnections for all users, each one containing a list of users, and a group of representative keywords for that group.
[0050] Method 400 then proceeds to block 404 , where method 400 calculates a relationship importance value based on the total sum of the importance values of its keywords that representing this relationship.
[0051] Method 400 then proceeds to block 405 , where method 400 stores these relationships in the user profile and relationship database (e.g. user profile and relationship database 208 ). In the database, each relationship has an importance value and a group of representative keywords, as well as a reference to a list of users in that group. The importance value represents the relative significance of this. The group of representative keywords are the outcome of the clustering algorithm (like block 210 ). The keywords are usually closely related in meaning and when clustered together, they also define the type of the relationship. For example, a relationship is represented by “George Bush, American Politics”. There could be active users on the topics of “George Bush, American Politics”, and they are included in this relationship. The keyword clustering method as summarized above is also described in greater detail in co-pending U.S. patent application Ser. No. 11/366,517.
[0052] Now referring to FIG. 5 , shown is an illustrative example of a method 500 for displaying the user interconnections. This process is activated, for example, when a user logs in his/her application or web page. The backend process retrieves the relationship groups and users that are related to the current user, formats them, and displays them, for example as hyperlinks. The relationships shown can be filtered by the user's current log-on role and context. For example, the relationships shown when a user logs on at home are different from the relationships shown when a user logs on at work.
[0053] Method 500 begins at block 501 with a user login, and proceeds to block 502 , where a relationship display module is activated upon user access of an application or webpage.
[0054] Method 500 then proceeds to block 503 , where the user profile and relationship database is searched to retrieve all relationships which contain the user, up to a maximum size as defined by the user, the most important relationships being retrieved first.
[0055] Method 500 then proceeds to block 504 , where for each relationship retrieved in block 503 , the user profile and relationship database is searched for other users in that relationship, up to a maximum size as defined by the user.
[0056] Method 500 then proceeds to block 505 , where the relationship list as retrieved in blocks 503 and 504 is formatted, with each relationship and its users being interconnected, for example by hyperlink in a web page interface.
[0057] Now referring to FIG. 6 , shown is a method 600 for managing a user profile. Method 600 begins with a user login at block 601 and proceeds to block 602 , where method 600 accesses the relationship profile section of the user. From block 602 , method 600 may proceed to any one of blocks 603 to 607 , where method 600 performs each of the following steps.
[0058] At block 603 , method 600 searches all relationships related to a keyword, so that a user knows the connections of a keyword to known relationships and the effects it can bring to the relationship building process by adding/removing this keyword to/from his/her profile. Method 600 then proceeds to block 604 , where method 600 modifies the user's keywords section (e.g. add, remove, modify, or move up or down in priority) so as to manually affect the relationship building process. Method 600 may also by-pass block 603 to go to block 604 directly. From block 604 , method 600 proceeds to block 608 , where the user exits his/her profile section.
[0059] At block 605 , method 600 may allow the user to turn the auto profiler and relationship display on or off. Method 600 may then proceed to block 608 where the user exits.
[0060] At block 606 , method 600 may allow the user to set the maximum number of relationships to which a user may be associated. Method 600 may then proceed to block 608 where the user may exit.
[0061] At block 607 , method 600 may allow the user to set the maximum number of users that can be displayed under any relationship. Method 600 may then proceed to block 608 , where the user may exit the profile section.
[0062] As will be appreciated, the user profile interface described above is meant to be interactive and configurable by the user to suit their needs. As well, the system in not static, but rather the user input can and will be used to influence the relationship group outcomes. For instance, the users can modify their own profiles so to manually affect the relationship generation process. For example, if the user has posted a message that has a word “rose” in it, but he doesn't want to be connected to people with a gardening interest, he/she can delete the keyword “rose” from his keyword profile. The profile can also be used to “discover” relationships in an area where the user has no electronic history based on the user's activity log. For instance if he has not had any electronic activities relating to “rose gardening”, but he wants to be connected to people with that interest, he can also manually add keywords to his keyword profile, which would cause the system to evaluate again, looking for new potential relationships. As well, the user can move the keywords to emphasis or de-emphasis an area. For example, if a user has lost interesting in rose gardening, the user may move those keywords down the priority list by reducing its weight.
[0063] The user can also limit the number of users that can be displayed under any discovered relationship. This can be done, for example, by displaying only the top five users and/or relationships. Similarly if the user is searching for more obscure topics, the user can specify relationships that fall in the range of the lower than 10 and higher than 25.
[0064] By managing the keywords, the users can expose, hide, and filter what information they or others see. In an embodiment, the user can also type in a keyword, and the system will present the keywords/clusters related to that keyword. This permits the ability to search a user's relationship map. For example, the keywords “pruning roses” may be typed in the system to show potential relationships and related keywords. In this manner, the user knows how she/he should handle that keyword in her/his profile.
[0065] While various illustrative embodiments of the invention have been described above, it will be appreciated by those skilled in the art that variations and modifications may be made. Thus, the scope of the invention is defined by the following claims.
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There is disclosed a method of facilitating interaction between users of an electronic community. In an embodiment, the method comprises: reviewing a user activity log for each user in the electronic community; executing a natural language parser to extract significant noun phrases from the user activity log; updating user profiles from the newly extracted noun phrases, based on their usage frequency and importance value; and storing the updated profiles in a user profile and relationship data base; and executing a similarity based clustering algorithm to cluster user profiles, thereby discovering relationships among users and storing them in a user profile and relationship database. The method may further comprise displaying for each user the one or more relationships to which the user is assigned, together with a list of users assigned to the one or more relationships. The method may also comprise storing for each user the relationship to which the user is assigned in a user profile and relationship database.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a divisional of U.S. patent application Ser. No. 12/135,229, filed Jun. 9, 2008, the disclosure of which is incorporated by reference herein its entirety.
BACKGROUND
The present invention relates generally to memory devices and, more particularly, to an apparatus and method for low power sensing in a multi-port SRAM using pre-discharged bit lines.
A typical static random access memory (SRAM) cell includes an array (rows, columns) of individual SRAM cells. Each SRAM cell is capable of storing a voltage value therein, which voltage value represents a corresponding binary logical data bit value (e.g., a “low” or “0” value, and a “high” or “1” value). One existing configuration for an SRAM cell includes a pair of cross-coupled devices such as inverters. Using CMOS (complementary metal oxide semiconductor) technology, each inverter comprises a pull-up PFET (p-channel) transistor connected to a complementary pull-down NFET (n-channel) transistor, with the two transistors in each inverter typically connected in series between a positive voltage potential and ground. The inverters, further connected in a cross-coupled configuration, act as a bistable latch that stores the data bit therein so long as power is supplied to the memory array.
The transistors within the typical SRAM cell exhibit relatively significant current leakage, particularly at the word-line transistor gates and the bit-line transistor gates. Since known SRAM cell designs require a constant power level both to maintain the data bit stored in the SRAM latch and to allow the reading from and the writing to of data, the current leakage increases the power used by the array of SRAM cells. For example, one common technique is to continuously pre-charge all of the read bit lines within the SRAM to a logical high level; that is, to a positive voltage of, e.g., +1 volts. This is done when the bit lines are not being accessed. After a read cycle involving certain read bit lines, those bit lines are returned to their pre-charge state. The resulting undesirable use of power in these prior art designs increases with the increase in SRAM cell density and the overall number of cells on an integrated circuit (IC), such as a stand-alone memory device, or as part of a processor or application-specific integrated circuit (ASIC).
Various techniques to reduce the leakage current have been proposed, such as increasing the size of the cell by making the devices longer, increasing the threshold voltages of the cell, adding additional transistors to the cell, or lowering the voltage to the array when the cell is not being accessed. However, all of these techniques can increase the area of the array, or significantly reduce the performance of the array.
What is needed is an apparatus and method to reduce the DC power consumption in a multi-port SRAM cell due to relatively large cell current leakage as well as to reduce the AC power consumption in the multi-port SRAM cell due to relatively large read bit line voltage swings.
SUMMARY
The foregoing discussed drawbacks and deficiencies of the prior art are overcome or alleviated, in an exemplary embodiment, by an apparatus for low power sensing in a multi-port SRAM using pre-discharged bit lines. In an exemplary embodiment, the apparatus includes a first switch that holds a bit line associated with the memory cell at a zero volt potential when the memory cell is not being accessed; a second switch that holds a sense line at a first voltage potential for a period of time after access to the memory cell has been allowed, wherein the sense line is connected to the bit line when the memory cell is being accessed, and wherein the bit line is energized to a second voltage potential different than the first voltage potential when the memory cell is being accessed; and a sense amplifier that senses the second voltage potential on the bit line when the memory cell is being accessed.
In another exemplary embodiment, a method for low power sensing in a multi-port SRAM using pre-discharged bit lines includes holding a bit line associated with the memory cell at a zero voltage potential when the memory cell is not being accessed; energizing the bit line to a first voltage potential different than the zero voltage potential during an access of the memory cell; and sensing the memory cell contents when the associated bit line has reached the first voltage potential.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to the exemplary drawings wherein like elements are numbered alike in the several Figures:
FIG. 1 is a schematic diagram of a multi-port SRAM cell;
FIG. 2 is a schematic diagram of circuitry that includes the SRAM cell of FIG. 1 and illustrates an exemplary embodiment of the present invention; and
FIG. 3 shows several signal timing diagrams within the circuitry of FIG. 2 .
DETAILED DESCRIPTION
Disclosed herein is an apparatus and method for low power sensing in a multi-port SRAM using pre-discharged bit lines. Briefly stated, the apparatus and method pre-charges the SRAM read port bit lines to a logic low level of zero volts (i.e., “pre-discharges” the bit lines). As a result, the read port bit lines of the multi-port SRAM do not leak DC current when pre-discharged as such. The apparatus and method holds the SRAM read port bit lines that are not being read at any particular point in time at ground (zero voltage) potential, and energizes selected read port bit lines (i.e., applies a potential thereto) only when the selected read port bit lines are accessed to read or sense the stored information within the selected memory cell. In addition, the potential applied to the selectively energized read bit lines is lower in value than the full rail voltage potential (typically +1 volts or Vdd); that is, the applied potential is at an intermediate value between Vdd and ground, thereby saving AC power due to relatively lower voltage swings on these lines.
Referring to FIG. 1 , there is shown a typical multi-port (e.g., two port) SRAM memory cell 100 . The cell 100 includes a base cell 102 that comprises six CMOS transistors 104 - 114 , wherein the base cell 102 constitutes both the write port of the memory cell 100 and the basic storage element of the memory cell 100 . FIG. 1 also shows a read port 116 in which both the true and complement read bit lines, rblt 118 , rblc 120 , are connected to a sense amp 122 (SA), shown in FIG. 2 , for sensing the logic value stored in the cell 100 . A plurality of the read ports 116 may be used as part of a single memory cell 100 , if desired.
The base cell 102 of FIG. 1 includes a bistable latch 124 comprising a first pair of PMOS (e.g., PFET) and NMOS (e.g., NFET) transistors 104 , 106 connected in series as an inverter between a positive power supply potential Vdd (e.g., +1 volts) and a ground potential (e.g., 0 volts). The latch 124 further comprises a second pair of PMOS and NMOS transistors 108 , 110 , also connected in series as an inverter between the power supply potential Vdd and ground. The transistors 104 , 106 have their respective gate terminals connected together at a storage node 126 , which is also connected to the drain terminals of both transistors 108 , 110 , which drain terminals are connected together. This storage node 126 is referred to as the “complement” node. Similarly, the transistors 108 , 110 have their respective gate terminals connected together at a storage node 128 , which is also connected to the drain terminals of both transistors 104 , 106 , which drain terminals are connected together. This storage node 128 is referred to as the “true” node. In normal operation of the base cell 102 , the true storage node 128 and the complement storage node 126 typically store complementary logic levels (i.e., one node stores a binary “1” while the other node stores a binary “0”, or vice versa). Thus, the PMOS transistors 104 , 108 operate as load transistors and the NMOS transistors 106 , 110 operate as drive transistors within the base cell 102 .
The base cell 102 also includes two NMOS transistors 112 , 114 . A first transistor 112 is connected between a true write bit line, wblt 130 , and the storage node 128 . A second transistor 114 is connected between a complement write bit line, wblc 132 , and the storage node 126 . Gate terminals of these transistors 112 , 114 are connected to a common write word line, wwl 134 . As such, the transistors 112 , 114 each have their respective gate potentials controlled by the write word line, wwl 134 .
The read port 116 further includes four NMOS transistors 136 - 142 . Two of the transistors 136 , 138 are connected in series between the true read bit line, rblt 118 , and ground. Another two of the transistors 140 , 142 are connected in series between the complement read bit line, rblc 120 , and ground. Gate terminals of two of the transistors 136 , 140 are connected to a common read word line, rwl 144 . As such, the transistors 136 , 140 have their respective gate potentials controlled by the read word line, rwl 144 . The gate of transistor 138 is connected to the complement storage node 126 in the base cell 102 , while the gate of transistor 142 is connected to the true storage node 128 in the base cell 102 . In general, the transistors 136 - 142 within the read port 116 do not necessarily need to be long channel or SRAM-type high voltage threshold devices. It suffices that these transistors 136 - 142 are such that any current leakage therethrough does not degrade the signal to a large enough extent to cause any read errors.
In operation of the base cell 102 and the read port 116 , when the common write word line, wwl 134 , is active, access to the cell for write or read operations is enabled. Thus, when wwl 134 is active, data may be written to the storage nodes 126 , 128 via the two complementary write bit lines, wblt 130 , wblc 132 , respectively. When the common write word line, wwl 134 , is inactive, the data previously written to the storage nodes 126 , 128 is held steady by the latch 124 comprised of the transistors 104 - 110 . When the common read word line, rwl 144 , is active, data is read from the storage nodes 126 , 128 via the two complementary read bit lines, rblt 118 , rblc 120 . In a typical SRAM memory cell 100 , it is not necessary to periodically assert the common write word line 134 (i.e., apply a voltage thereto) to refresh the data held in the latch 124 . The data will be held in a steady state in the latch 124 as long as power is continuously applied to the cell 100 .
FIG. 2 shows an exemplary embodiment of the present invention. In the multi-port SRAM, multiple rows 200 , 202 of SRAM memory cells 100 (two rows 200 , 202 are shown, each row having a plurality of cells 100 ) may each be connected to the sense amp 122 . For each row 200 , 202 of cells 100 , the cells 100 are connected together by the respective read bit lines: rblt 0 204 and rblc 0 206 for row zero 200 ; rblt 1 208 and rblc 1 210 for row one 202 . These read bit lines 204 - 210 are the read bit lines 118 , 120 originating from the read port 116 in FIG. 1 . Each read bit line 204 - 210 is connected to the sense amp 122 through a corresponding bit switch circuit, where each bit switch circuit is comprised of an NFET pass gate transistor 212 - 218 , each having a relatively high voltage threshold. The true read bit lines 204 , 208 of each row 200 , 202 pass through the corresponding bit switch circuits 212 , 216 and connect together as a true sense line, slt 220 . Similarly, the complement read bit lines 206 , 210 of each row 200 , 202 pass through the corresponding bit switch circuits 214 , 218 and connect together as a complement sense line, slc 222 . The gate terminal of each bit switch circuit NFET transistor 212 , 214 for row zero 200 is controlled (i.e., the NFET transistor is turned “on”) by a positive active signal line, bso 224 . Similarly, the gate terminal of each bit switch circuit NFET transistor 216 , 218 for row one 202 is controlled by a positive active signal line, bs 1 226 . The sense lines 220 , 222 are provided to the sense amp 122 , which is enabled by a sense signal line, set_en 228 .
FIG. 2 also illustrates that, in accordance with the present invention, the apparatus further includes an NFET transistor 230 - 236 for a corresponding one of each of the read bit lines 204 - 210 . The drain terminal of each NFET transistor 230 - 236 is connected to the corresponding read bit line 204 - 210 , while the source terminal of each transistor 230 - 236 is connected to ground. The gate terminal of each transistor 230 - 236 is connected to a common positive active control signal line, pdbl 238 . As described in detail hereinafter, when one or more of the transistors 230 - 236 are turned on, the corresponding read bit line 204 - 210 is pulled down to ground potential, thereby “pre-discharging” the corresponding read bit line 204 - 210 , with the result being that no DC current leakage occurs on these lines 204 - 210 when pre-discharged as such.
In FIG. 2 , the sense lines, slt 220 and slc 222 , are also connected to a sense line pre-charge control circuit that comprises three PFET transistors 240 - 244 . The gate terminals of all three transistors 240 - 244 are connected to a negative active sense line pre-charge signal, xpusl 246 . When this signal, xpusl 246 , turns on each of the transistors 240 - 244 , the sense lines, slt 220 and slc 22 , are pre-charged to a high logic level of Vdd (e.g., +1 volts).
In the apparatus of FIG. 2 in accordance with an exemplary embodiment of the present invention, the read bit lines 204 - 210 are pre-charged to a logic low level of, e.g., ground or zero volts (“pre-discharged”), through the NFET transistors 230 - 236 , rather than to a logic high level of, e.g., Vdd or +1 volts, as in the prior art. Also, as compared to prior art dual-ended sensing apparatus and methods, the bit switch circuit transistors 212 - 218 now comprise relatively high threshold voltage (Vt) NFETS instead of PFETS. In addition, the polarity of the transistor controls signals (i.e., the gate voltage signals) agree with their respective transistor device-types, and the timing of the sense line pre-charge control signal, xpusl 246 , has been changed, as illustrated in FIG. 3 . These changes do not increase the area occupied by the SRAM memory cell 100 . In fact, in practice it has been discovered that the area is reduced slightly.
When the read bit lines 204 - 210 are pre-discharged to a logic low level, no DC leakage occurs through the read ports 116 of the SRAM. A slight delay in reading out the stored data occurs because the read bit lines 204 - 210 are energized to an intermediate voltage level between Vdd and ground prior to their sensing or reading out of the stored values therefrom. This is done by keeping the sense line pre-charge control signal, xpusl 246 , active for a short period of time after the word line, wwl 134 , has been activated, as shown in FIG. 3 . AC power is reduced because only selected ones of the bit lines 204 - 210 that are being read are energized at any particular point in time, and also because, even when energized, the selected bit lines 204 - 210 are not fully charged to Vdd but to a voltage that is intermediate between Vdd and ground.
Referring also to FIG. 3 , there illustrated are several signal traces of voltage values versus time at different points in the circuit of FIG. 2 . The respective bit switch control signals, bs 0 224 , bs 1 226 , are active high as shown in FIG. 2 and in the top trace 300 . In the example shown, row 1 202 is activated because the pass gate transistor control signal, bs 1 226 , assumes a logic high value shortly after time t=1, thereby turning on NFETS 216 , 218 , while the pass gate transistor control signal, bs 0 224 , remains at a low logic level, thereby keeping NFETS 212 , 214 off and not allowing the read bit signal lines, rblt 0 204 and rblc 0 206 , to influence the sense lines, slt 220 and slc 222 .
As shown in the next trace 302 , the pre-discharge control signal, pdbl 238 , for the NFETS 230 - 236 assumes a low logic level also shortly after time t=1, thereby turning off the NFETS 230 - 236 (i.e., removing the “pre-discharge” or zero volt state of the read bit lines 204 - 210 ). Also, shortly after time t=1, the common read word line, rwl 144 , assumes a high logic level, thereby allowing access to the cell 100 . The sense line pre-charge control signal, xpusl 246 , stays at a logic low until approximately t=2, at which time it changes to a logic high, thereby turning off the PFETS 240 - 244 . This delay between rwl 144 going high and xpusl 246 going high allows the selected read bit lines (here, rblt 1 208 and rblc 1 210 ) to become energized to a voltage value intermediate between Vdd and ground, as described hereinafter.
The next trace 304 shows the read bit lines for the selected row, row 1 202 , in which the true read bit line, rblt 1 208 , and the complement read bit line, rblc 1 210 , are energized and start to increase in voltage beginning shortly after time t=1. The read lines will achieve a voltage value intermediate between Vdd (e.g., +1 volts and ground). This increase in voltage is due to the aforementioned delay between rwl 144 going high and then xpusl 246 going high. That is, the sense line pre-charge PFETS 240 - 244 remain turned on for a short time after rwl 144 is activated until xpusl 246 also goes high, which allows for charge-sharing from the sense lines, slt 220 and slc 222 , to the bit lines rblt 1 208 and rblt 0 210 , of the selected row 202 . One of the bit lines, rblt 1 208 , will not rise in voltage as quickly as that of the other bit line, rblc 1 210 , due to the “0” state of the selected cell 100 in this exemplary embodiment.
The next trace 306 shows the sense lines, slt 220 and slc 222 , and the set enable signal, set_en 228 . As compared to the prior art, the set enable signal is delayed slightly in transitioning from logic low to logic high (at approximately time t=3) to account for the time it takes to energize the read bit lines 208 , 210 . Consequently this delays the sense line resolution, which is the time at which the sense line signal, slt 220 , assumes a logic low (i.e., at approximately time t=4). Thereafter the logic bit values on the selected read bit lines can be sensed or read by the sense amp 122 .
The apparatus and method of the present invention pre-charges the read port bit lines 204 - 210 to a logic low level when they are not being read or sensed so that the read ports 116 of the multi-port SRAM do not unnecessarily leak DC current. The bit lines 204 - 210 are held at ground and energized only when they are accessed, as shown in FIG. 3 . Hence the read port DC leakage due to the SRAM cells is significantly reduced, as compared to prior art schemes that pre-charge the read bit lines to Vdd. There is a small amount of current leakage through the bit switch transistors 212 - 218 . However, this amount of leakage is significantly less than that of the cells for all but the smallest SRAM sizes. In addition, the AC power is reduced because the bit lines 204 - 210 are not fully charged to a full voltage rail potential (e.g., of Vdd) when they are energized (as shown in FIG. 3 ), and also because only the bit lines 204 - 210 that are being read are energized. When the selected read bit lines 204 - 210 are energized, some current leakage occurs. However, because typically only a selected few, and not all, of the bit lines are energized at any one point in time, the overall amount of current leakage caused by the energized bit lines is significantly lower then in the prior art where all of the bit lines are typically pre-charged to Vdd.
The read performance is delayed slightly to allow the bit lines to energize to some intermediate voltage lower than Vdd prior to the read operation. The delay penalty is small, and depends on the technology voltage and temperature. For example, in a 65 nm CMOS bulk technology at a slow process corner and low voltage, the delay penalty is about 60 ps. At a 1 GHz cycle time, this would represent a 6% decrease in performance. With newer technologies, the write time of the cell limits the performance more than the read time, so delaying the read slightly may not affect overall performance at all. Implementation of the present invention requires no additional area over current multi-port SRAM designs and does not change the design structure of the sense amp 122 .
The expected power savings brought about by the present invention depends on the memory configuration and the operating voltage. For example, at 1V in a 65 nm CMOS-bulk technology, a two-port array configured as 8 columns with 64 cells per column, a savings of approximately 654 nW per sense amp occurs. At a cycle time of 900 ps, the AC power savings are 2400 nW per sense amp. For an ASIC design employing 60 two-port SRAM macros, each with 2000 sense amps, then approximately 78 mW leakage and 0.29 W AC power per chip may be saved.
While the invention has been described with reference to a preferred embodiment or 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 the 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.
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A method for sensing the contents of a memory cell within a static random access memory (SRAM) includes holding a bit line associated with the memory cell at a zero voltage potential when the memory cell is not being accessed; energizing the bit line to a first voltage potential different than the zero voltage potential during an access of the memory cell; and sensing the memory cell contents when the associated bit line has reached the first voltage potential.
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TECHNICAL FIELD
This invention relates to dispensing cartridges and, more particularly to dispensing cartridges in which a user does not come into contact with the dispensed product prior to insertion of the dispensing cartridge into a receiving machine, and method therefore.
BACKGROUND
In industrial environments, it is commonly desirable to be able to insert a product, usable in a machine, into that machine without the user or operator of the machine coming into direct contact with the product. This is particularly true when the product is caustic or corrosive, or when it would otherwise be detrimental for the user or operator to come into direct contact with product.
This is particularly true in industrial laundry or washing environments where it is common for detergents and other wash aids, such as rinse aids, to be replenished in washing equipment.
Many detergents products are distributed in solid form and are dissolved in use in the machine into which the solid detergent product is utilized. Such dissolvable solid products, of which detergent is just one example, are commonly distributed in containers.
A thermoformed blister pack or a package with a lid could be used to distribute dissolvable solid detergents. This would typically require the user to remove the back or lid from the package and drop the solid detergent block into the machine utilizing the detergent. Unfortunately, this technique would expose the user of the machine to direct contact with the solid detergent block which is not desirable.
One solid dissolvable detergent block has been distributed in a shrink wrapped plastic film. Small pin holes in the film allow the evacuation of otherwise trapped air as the film shrinks to conform to the shaped of the detergent block as the detergent block is packaged. Unfortunately, these same pin holes allow moisture from the atmosphere to enter the package. The addition of moisture to a detergent block package causes the detergent block package to swell around each of the pinholes resulting in an unsightly product.
Plastic, blow molded bottles have also been used as dispensers for this type of material but such plastic, blow molded bottles also suffer from many of the disadvantages of the other packages discussed.
SUMMARY OF THE INVENTION
The present invention provides a dispensing cartridge for a product usable in a machine, particularly a dissolvable solid product, which can not easily contact the user during insertion, yet is readily usable by the machine. Also, the dispensing cartridge is economic to construct and is easy to handle by the user.
In one embodiment, the present invention provides a dispensing cartridge for holding a product adapted to be inserted into a machine configured to utilize the product. A container has a bottom and at least one side wall. The bottom of the container has an opening configured to cooperate with the machine. A removable cover closes the opening in the container and prevents contact with the product before the dispensing cartridge is inserted into the machine.
In one embodiment, the present invention provides a dispensing cartridge for holding a product adapted to be inserted into a machine configured to utilize the product. A container has a bottom and at least one side wall. The bottom of the container has an opening configured to cooperate with the machine. A removable cover closes the opening in the container and prevents contact with the product before the dispensing cartridge is inserted into the machine.
In a preferred embodiment, the removable cover is formed within the bottom of the container by perforations in the bottom of the container.
In a preferred embodiment, the removable cover is placed over the opening.
In another embodiment, the present invention provides a dispensing cartridge for holding a product adapted to be inserted into a machine configured to utilize the product. A container has a bottom and at least one side wall. The bottom of the container has an opening configured to cooperate with the machine. A removable label covers the opening in the container and prevents contact with the product before the dispensing cartridge is inserted into the machine.
In a preferred embodiment, the removable label is adhesive backed.
In another embodiment, the present invention provides a dispensing cartridge for holding a dissolvable solid product adapted to be inserted into a machine configured to utilize the dissolvable solid product by dissolving the dissolvable solid product from the dispensing cartridge. A container has a bottom, a top and at least one side wall. The bottom of the container has an opening configured to cooperate with the receptacle of the machine when the dispensing cartridge is inserted into the machine. The bottom of the container is formed from at least two angled side walls forming an acute angle at the bottom of the container. The container has a handle for aiding carrying of the dispensing cartridge before the dispensing cartridge is inserted into the machine. A removable, adhesive backed label covers the opening in the bottom of container, hermetically sealing the container, and prevents contact with the dissolvable solid product before the dispensing cartridge is inserted into the machine.
In another embodiment, the present invention provides a dispensing cartridge for holding a solid detergent product adapted to be inserted into a machine configured to utilize the solid detergent product by dissolving the solid detergent product from the dispensing cartridge. A container has a bottom, a top and at least one side wall. The bottom of the container has an opening configured to cooperate with the receptacle of the machine when the dispensing cartridge is inserted into the machine. The bottom of the container is formed from at least two angled side walls forming an acute angle at the bottom of the container. The container has a handle for aiding carrying of the dispensing cartridge before the dispensing cartridge is inserted into the machine. A removable, adhesive backed label covers the opening in the bottom of container, hermetically sealing the container, and prevents contact with the solid detergent product before the dispensing cartridge is inserted into the machine.
In a preferred embodiment, the container is thermoformed.
In a preferred embodiment, the container is a clamshell.
In a preferred embodiment, the handle is formed into the top of the container.
In another embodiment, the present invention provides a method of dispensing a dissolvable solid product into a machine. The dissolvable solid product is held in a dispensing cartridge. The dispensing cartridge is a container having a bottom and at least one side wall, the bottom of the container having an opening configured to cooperate with the machine, and a removable label covering the opening in the bottom of container preventing contact with the dissolvable solid product. The removable label is removed from the opening in the bottom of the container. The dispensing cartridge is inserted into the machine. The dissolvable solid product is dissolved from the dispensing cartridge.
In a preferred embodiment, the product is a detergent.
In a preferred embodiment, the product is a sanitizer product.
In a preferred embodiment, the product is a caustic product.
In a preferred embodiment, the product is a corrosive product.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is an isometric view of an embodiment of a dispensing cartridge according to the present invention with the cartridge open;
FIG. 2 is a top view of the dispensing cartridge of FIG. 1 ;
FIG. 3 is an isometric view of an embodiment of a dispensing cartridge according to the present invention with the cartridge closed holding a detergent block;
FIG. 4 is a view of the dispensing cartridge of FIG. 3 closed holding a detergent block showing an opening through which the detergent block may be dissolved;
FIG. 5 is a view of the dispensing cartridge of FIG. 3 and FIG. 4 showing the opening through which the detergent may be dissolved covered with a label;
FIG. 6 is an alternative embodiment of a dispensing cartridge according to the present invention with an opening created from perforations.
DETAILED DESCRIPTION
FIGS. 1 and 2 show an embodiment of dispensing cartridge 10 of the present invention open and without holding any product. Dispensing cartridge 10 can be thermoformed from a single piece of polyvinylchloride (PVC), polyethylene teraphalate (PET) and, preferably, high density polyethylene (HDPE). It is roughly divided into a first half 12 and a second half 14 along hinge line 16 . First half 12 is formed with a first bubble 18 and second half 14 is formed with a second bubble 20 . Dispensing cartridge 10 is designed to be folded along hinge line 16 using location guides 22 , 24 as an aid and be sealed around the periphery of dispensing cartridge 10 with the exception of hinge line 16 . First bubble 18 and second bubble 20 form a space, when dispensing cartridge 10 is closed, for holding a product to be dispensed, preferably a dissolvable solid product, such as a detergent block or a sanitizer block. A portion of both first half 12 and second half 14 near hinge line 16 is formed with angled sidewalls 30 and 32 , respectively, forming an acute angle at hinge line 16 . In this embodiment, first half 12 and second half 14 are about 6.625 inches (16.8 centimeters) by 5.75 inches (14.6 centimeters) and 2.139 inches (5.4 centimeters) deep.
Handle 26 is formed into one side of second half 14 opposite from hinge line 16 . In this embodiment, handle 26 extends about 1.75 inches (4.45 centimeters) beyond second bubble 20 in second half 14 and extends along the long dimension of second half 14 . Handle 26 allows dispensing cartridge 10 to be easily carried and to be easily inserted into a machine (not shown) into which the product is to be dispensed.
An opening 28 is cut into angled sidewalls 30 and 32 at and on either side of hinge line 16 . Opening 28 is small enough to prevent the product to be dispensed from falling from dispensing cartridge 10 but large enough to allow the product to be dispensed from dispensing cartridge 10 when dispensing cartridge 10 is inserted into a receiving machine. In this embodiment, opening 28 is an oval having a longer diameter of approximately 1.75 inches and a shorter diameter of approximately 1 inch.
In this embodiment, dispensing cartridge 10 is transparent allowing a user to visually determine the amount of the product to be dispensed remaining in dispensing cartridge 10 .
FIGS. 3 and 4 show an embodiment of dispensing cartridge 10 in a closed position holding solid product 34 to be dispensed. In this condition, dispensing cartridge 10 has had opening 28 opened by the user and dispensing cartridge 10 is ready to be inserted into the machine into which solid product 34 is to be dispensed. These figures illustrate the ease with which dispensing cartridge 10 may be carried and inserted into the machine into which solid product 34 is to be dispensed. In operation, once inserted, liquid, preferably water, from the machine is allowed to circulate in the proximity of opening 28 . Solid product 34 , such as a detergent block, being dissolvable by such liquid, is gradually dissolved out of dispensing cartridge 10 and advantageously utilized by the machine, such as a laundry machine.
FIG. 5 shows an embodiment of dispensing cartridge 10 having label 36 secured over opening 28 . Label 36 is secured in place over opening 28 with adhesive 38 . It is preferred that label 36 be adhesive backed. In this embodiment, solid product 34 is distributed to the end user with label 36 in place. With label 36 in place, a user can not come into contact with solid product 34 . If solid product 34 were a caustic or a corrosive product, a user would be spared direct contact with such product.
A user would remove label 36 from dispensing cartridge 10 prior to inserting dispensing cartridge 10 into the machine into which solid product 34 is to be dispensed. Even though label 36 has been removed, the relatively small surface area of dispensing cartridge 10 through which solid product 34 is exposed and the ease of manipulating dispensing cartridge 10 with handle 26 makes it easy for a user to avoid any direct contact with solid product 34 .
FIG. 6 shows an alternative embodiment of dispensing cartridge 10 in which a covering for opening 28 is formed with the material used to formed first half 12 and second half 14 . In this embodiment, instead of directly forming or cutting an opening into angled sidewalls 30 and 32 , a potential opening 40 is created by perforations 42 . Distributed with potential opening 40 still covering solid product 34 , a user may easily tear potential opening 40 into opening 28 by removing the material of angle sidewalls 30 and 32 by tearing at perforations 42 .
Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not limited to the illustrative embodiments set forth above.
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A dispensing cartridge for holding a product adapted to be inserted into a machine configured to utilize the product. A container has a bottom and at least one side wall. The bottom of the container has an opening configured to cooperate with the machine. A removable cover closes the opening in the container and prevents contact with the product before the dispensing cartridge is inserted into the machine.
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REFERENCE TO RELATED APPLICATION
Application is a 371 of PCT/FR99/00315, filed Feb. 12, 1999 which in turn claims priority to France 98 01741 filed Feb. 13, 1998 Both documents are incorporated by reference for all purposes.
FIELD OF THE INVENTION
The present invention relates to a set of plant promoters which can be induced by biotic or abiotic stresses, in particular by pathogens, to their use, to expression vectors comprising said promoters and a gene of interest, and to cells and/or plants transformed with said vectors. The invention also relates to methods for obtaining said cells or plants, said transformed plants exhibiting improved resistances to said pathogens.
BACKGROUND OF THE INVENTION
Diseases, whether they are of fungal, bacterial or viral origin, are the major problem in viticulture, both in terms of the quality of the musts and of the wines produced (for example Botrytis cinera, which is a grey mould agent which attacks the berries at grape-harvesting and leads to bad tastes in the wines), drops in production (for example foliar diseases such as grape downy mildew or grape powdery mildew, attacks by Botrytis on flowers or Fan leaf disease of the grapevine linked to the presence of the virus G.F.L.V., Grape Fan Leaf Virus), or even to that of the survival of the vineyard (for example wood diseases such as eutypiosis or esca syndrome). The conventional control arsenal ranges from simple prophylaxis to plant-protection treatments, biological control to date being used very little.
Chemical control is of course the most widely used method, even though treatments are increasingly being tempered (models for forecasting risks of disease for grape downy mildew for example). With regard to fungicides for example, the French vineyard, which represents approximately 10% of the cultivated land in France, each year uses close to 40% of the fungicides consumed in this country. On a European level, on close to 4 million hectares of vineyard, the 9 to 10 treatments which are carried out each year to control these diseases lead to the use of 120,000 tonnes of fungicidal products.
To cite just the problem of grey mould, it is estimated that over the years 1992 to 1993, 25 to 30% of the 3.7 million hectares of European vineyard were concerned, for a cost of plant-protecting products of 97 and 69 million German Marks (DM), respectively.
The use of these products is not without consequence for the environment (it is the case, for example, for the soil fumigants used to destroy nematodes, which are vectors of the grape fan leaf virus). It also sometimes poses technological problems, with difficulties which can occur during fermentations (the use of sterol biosynthesis inhibitors can block yeast growth at the end of fermentation) and commercial difficulties (procymidone, an anti-Botrytis product, which is sometimes found in wines, hence the American dispute in the years 1990 to 1991).
Moreover, the use of these products has already led to the appearance of resistant strains. This phenomenon has been particularly marked in Champagne and, for some years, the “Comité Interprofessionnel des Vins de Champagne” (CIVC) [Interprofessional Committee of the Wines of Champagne] has recommended not treating against Botrytis.
To overcome these drawbacks, it is imperative to balance the use of plant-protecting products by developing novel methods of control in order to considerably decrease the amounts of products spread over vineyards.
Two approaches are currently envisaged:
Reinforce prophylaxis and decrease the amount of products used (cultivation methods and preventive control, models for forecasting risks of disease, novel spreading materials, novel, more degradable molecules, etc.).
Improve the resistance of the grape varieties to disease.
For this second approach, conventional genetic improvement via the sexual pathway (hybridization with tolerant varieties) is impossible according to French legislation on Appellations d'Origine Contrôlée (A.O.C.) (registered designations of origin) which imposes the grapevine varieties which are to be used for a given appellation (designation). In addition, technically, grapevine, which is a ligneous plant, would require several tens of years to integrate one or more novel resistance properties while at the same time conserving the biochemical and aromatic properties of the grapevine varieties, which are factors of the organoleptic quality of the wines produced.
The control of the regeneration and of the genetic transformation of the grapevine, which has been carried out by the research team of the laboratories of the applicant company since 1988-1990, has made it possible to envisage using the modern techniques of cellular and molecular biology to increase the tolerance of grapevine varieties to fungal diseases.
Henceforth, it is possible, on the one hand, to integrate, into the genome of the grapevine, one or more homologous or heterologous genes which enable the overexpression or expression of a molecule of interest, which is of protein or other nature, and/or the opening of a new biosynthetic pathway and, on the other hand, to regenerate a plant which is more tolerant to one or more diseases, i.e. which has defense mechanisms which are reinforced with respect to the pathogen(s) in question.
There are several different mechanisms of this type in plants. Some can be regarded as being passive and are linked to the physicochemical properties of the cells, epidermal tissues and/or organs of the plant (for example the cuticle or the morphological properties of the grape cluster). Others belong to the dynamics of gene/gene interactions (plant resistance genes and pathogen avirulence genes, mechanisms of host/parasite interactions). These interactions can lead to the development of hypersensitivity reaction (rapid death of the cells of the plant around the point of infection in order to block the colonization of the plant by the fungus, bacterium or virus), but also to the synthesis and to the accumulation of a whole series of compounds. Among these, some can be parietal constituents which are involved in the formation of a “physical” barrier around the point of infection (callose, lignin, hydroxyprolinerich protein, etc.), and others are molecules having antimicrobial functions which are more or less well defined (phytoalexins, pathogen-associated proteins: PR proteins (pathogenesis-related protein), etc.).
The overexpression of these molecules which have antimicrobial functions or which are involved in the formation of a physical barrier around the point of infection can provide plants with a “natural” resistance in response to stresses, in particular stresses of microbial type.
However, constitutive overexpression of this type of protein cannot be envisaged without drawbacks for the plant (energetic cost, slowing down of growth, etc.), which is why it is necessary to envisage the use of inducible promoters and in particular of promoters which are inducible by the stress itself. This is precisely the subject of the present invention.
The present invention relates to a nucleic acid sequence chosen from the group comprising:
a) the IND S1 sequence,
b) any sequence corresponding to a fragment of the IND S1 sequence and having a promoter sequence effect in plants.
The invention also relates to promoters in plants, chosen from the group comprising:
a) the promoter PMs PR10-1 corresponding to the IND S1 sequence,
b) a promoter of PMs PR10-1 type corresponding to a sequence according to the invention.
Said promoters of PMs PR10-1 type are preferred which exhibit at least 80% homology with the IND S1 sequence. Those which exhibit at least 90% or 95% homology with said sequence are particularly preferred. The promoter sequences in plants which are characterized in that they comprise at least one sequence which is identical to those of the abovementioned promoters are also included in the present invention.
The subject of the invention relates most particularly to the use of the promoters according to the invention for the tissue-specific or non-tissue-specific expression of a gene in a way which is inducible in plants by a biotic or abiotic stress.
Among said biotic stresses according to the invention, the biotic stresses engendered by the attack of a parasite such as a virus, bacterium, yeast or fungus are particularly preferred.
Among said abiotic stresses according to the invention the abiotic stresses engendered by a mechanical wound, such as that caused in particular by an insect or by a physical phenomenon such as wind or frost, are particularly preferred.
The promoters or promoter sequences according to the invention can be used to prepare systems for expression in plants, the systems being able to be inducible and/or constitutive depending on the plant tissues or organs transformed (cf. Examples 2, 3 and 4).
These promoters were obtained from the regulatory sequences of PR protein genes in lucerne. Advantage was taken of the incompatibility response (hypersensitivity reaction, HR) obtained in the host/parasite relationship between lucerne ( Medicago sativa ) and Pseudomonas syringae pv pisi in order to study the promoter which is responsible for this reaction.
When Pseudomonas attacks lucerne, the appearance of a plant reaction is observed in the region of infection.
The plant material was thus removed following the bacterial attack in order to construct a cDNA library from the messenger RNAs produced in the infected regions adjacent to the necrosis. An amplification by polymerase chain reaction (PCR), using synthetic polynucleotides corresponding to motifs which are conserved in PR protein genes of leguminous plants, made it possible to obtain a radioactive probe which was then used to select transcripts in the cDNA library. Among these, one of them was retained since, after sequencing, it exhibited good homology with equivalent genes encoding PR proteins which are known for other plants (cf. FIGS. 1 and 1 a which represent the general scheme of the method for isolating the promoter).
The analysis showed that it corresponded to a gene encoding a class 10 PR protein according to the van Loon (1994) classification. This gene was therefore designated Ms PR10-1 ( Medicago sativa class 10 PR protein, clone 1).
A subject of the present invention is also systems which are for expressing a gene in plants and which are characterized in that they comprise at least the sequence of said gene under the control of a promoter or of a sequence according to the invention. Among the expression systems according to the invention, expression vectors, and in particular plasmid-type expression vectors, are preferred. Advantageously, said expression vectors are characterized in that they can be transferred into strains of Agrobacterium.
A subject of the invention is also a system or vector for expressing a gene in plants according to the invention, characterized in that it is inducible in plants by a biotic or abiotic stress, preferably a biotic or abiotic stress such as those described above.
The invention also relates to the systems or vectors according to the invention, characterized in that said gene is a gene of interest.
A gene is considered to be a gene of interest if its modification may be desired or used in any type of industry, including agriculture. Besides the already mentioned agriculture, industries such as, for example, the agrofoods industry, the cosmetics industry, the pharmaceutical industry, the chemical industry, etc. will come to mind. This list of examples is not, of course, limiting.
The gene may thus be, for example, a gene of agronomic interest or a gene which enables the plant to produce substances having a value for human or animal nutrition or health. Among the genes of agronomic interest, please note, for example, any gene whose expression makes it possible to modify the physiology of the plant, such as in particular inhibiting, slowing down, accelerating or triggering steps or phenomena which are involved at a given period in the life of the plant, or any gene whose expression makes it possible to improve or decrease the resistance of the plant to physical, chemical or biological attacks. Among the genes of interest which enable the plant to produce substances having a value for human or animal nutrition or health, is meant, for example, the genes which encode pharmaceutical or enzymatic compounds (which can be used for the biosynthesis or biodegradation of organic compounds) or compounds with nutrient value, or genes which make it possible to modify or to inhibit the expression of pharmaceutical, nutrient or toxic compounds or of aromas.
The invention comprises in particular the systems or vectors according to the invention, characterized in that said gene of interest is a gene which is involved in the response to a biotic or abiotic stress, preferably in the response to the inducing biotic or abiotic stress.
Preferably, the invention relates to the systems or vectors according to the invention, characterized in that the biotic stress is the attack of a parasite and the gene of interest is a gene of resistance to said parasite.
Even more preferably, the invention comprises the systems or vectors according to the invention, characterized in that the parasite is a virus, a bacterium, a yeast or a fungus, and the gene of interest is a gene which is involved in the synthesis of a molecule with anti-pathogen action, preferably a gene which is involved in the synthesis of phytoalexins or of PRs.
The constructs which enable the expression of these genes may of course comprise, besides the gene of interest, in particular coding strand 3′-end polyadenylation sequences, as well as enhancer sequences of said gene or of a different gene.
Of course, the constructs will have to be adapted in order to ensure that the gene will be read in correct reading frame with the promoter, and it will obviously be possible to envisage using if this is necessary, several promoters of the same type, as well as several enhancer sequences.
It is also possible to express, with the aid of the promoters according to the present invention, several genes, which are either placed in cascade or carried by different expression systems.
Among the genes of interest which can be expressed by the constructs according to the present invention, mention should be made of the genes which can be placed under the control of the promoter PMs PR10-1 in order to trigger mechanisms of resistance to the plant pathogens which are viroids, viruses, phytoplasmas, bacteria and fungi, or also even the resistance to insects or to ravages (the promoter also being inducible, in tobacco in particular, by wounds).
Among the possible strategies, reference may be made to the reviews by LAMB et al., 1992; VAN LOON et al., 1994; BROOGLIE and BROOGLIE, 1993; CHET, 1993 and to that by PAPPINEN et al., 1994.
By way of example, mention may be made, whether they are homologous or heterologous, of the genes encoding:
hydrolytic enzymes such as chitinases (BROOGLE et al., 1991) or β1-3 glucanases (KAUFFMAN et al., 1987), or combinations of genes encoding these two enzymes,
PR proteins (VAN LOON et al., 1994) such as osmotin (LIU et al., 1994, ZHU et al., 1995), thaumatin-like PR-proteins (VIGERS et al., 1992) or class 1 PR proteins (CUTT et al., 1989; HAHN K. and STRITTMATTER G., 1994),
RIP proteins (ribosome Inactivating Protein) of plants (LOGEMANN J. et al., 1992) or of other organisms or microorganisms,
proteins which have an inhibitory role for fungus attack enzymes: protease inhibitor (MASOUD et al., 1993), polygalacturonase-inhibiting proteins (TOUBART et al., 1992) or other inhibitory proteins,
lectins or chitin binding proteins (BROEKAERT et al., 1989; LERNER and RAIKHEL, 1992),
proteins such as (T4) phage or mammalian lysozyme (DURING et al., 1992),
proteins which are involved in the phytoalexin biosynthetic pathway (HAIN et al., 1993),
antimicrobial peptides such as defensin (BROEKAERT et al., 1995; VIGERS et al., 1991; TERRAS et al., 1995),
pathogen-resistance proteins (DE WIT, 1992) which are involved in or trigger hypersensitivity reactions (STRITTMATTER et al., 1995) or enzymes which lead to the production of hydrogen peroxide (WU et al., 1995),
proteins which lead to the production of antifungal, antibacterial or anti-insect toxins (KINAL et al., 1995),
proteins with peroxidase function which can intervene in lignin polymerization (LAGRIMINI et al., 1987) or in other oxidative reactions (BRADLEY et al., 1992),
proteins of viral origin, such as proteins of the shell of viruses in the sense or antisense position (see BEJARANO and LICHTENSTEIN, 1992),
proteins which are involved in the synthesis of molecules which trigger the signal transduction chain of stress mechanisms (jasmonic acid, salicylic acid, etc.) or proteins which are themselves involved as a stress signal or intermediates in the transduction chain (systemin, GTP binding proteins) for this, see SCHEEL et al., 1991, VERMA et al., 1994; VERA-ESTRELLA et al., 1994),
proteins which are toxic for insects (VAECK et al., 1987).
This list is not limiting.
A subject of the present invention is also plant cells which are transformed with a system or vector according to the present invention. Advantageously, said plant cells are grapevine cells and the gene of interest is a gene which confers resistance to a parasite.
The present invention also relates to methods for obtaining cells, characterized in that plant cells are transformed with the aid of a microbiological method which includes an expression system or a vector according to the invention.
Among the most widely used transformation methods, mention should be made in particular of the methods which use Agrobacterluin, whether it is Agrobacterium tumefaciens or Agrobacterium rhizogenes.
These methods are known, and they will not be described again in detail.
This technology, using plasmid systems, makes it possible to carry out a first transformation of a strain of competent bacteria, generally E. coli, which makes it possible to control the structure of the plasmids, and then the strain is used to transfer the recombinant plasmids into strains of agrobacteria which will then be used to transform the plant cells.
The present invention also relates to the transformed plant cells obtained by this method.
The invention also comprises a method for obtaining a plant expressing a gene of interest, characterized in that plant cells of said plant are transformed with the aid of a system or of a vector according to the invention, the cells expressing the gene of interest are selected and a plant is regenerated from said selected cells.
The invention also comprises the plants which comprise a system or a vector according to the invention, and/or cells according to the invention, preferably the plants obtained by implementing a method according to the invention.
It should in particular be noted that the constructs according to the present invention and which use the inducible promoters have made it possible to transform diverse plants, in particular tobacco ( Nicotiana benthamiana ), lucerne ( Lotus corniculatus ) and also grapevine (Vitis sp.).
It has also been possible, moreover, to demonstrate the advantage of the promoter according to the present invention during the regeneration of plants from cells. Specifically, the promoters of equivalent constructs which use strong constitutive promoters have never made it possible to obtain regenerated plants and it might be that the production of defense proteins leads very rapidly to the necrosis of the cells, thus preventing regeneration. This is an additional advantage of the constructs according to the present invention in some systems of plant transformation and regeneration.
Other properties and advantages of the constructs and of the methods according to the present invention may be demonstrated in the examples which follow.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 1 a : general scheme representing the various steps of the method for isolating the inducible promoter FMs PR10-1 corresponding to the IND S1 sequence.
FIG. 2 : representation which is of the various clones isolated and corresponds to a Southern blot, hybridized with the 5′- and 3′-portions of DNA-PR7, which are delimited by an internal Barn HI site (B) which was detected in this cDNA.
FIG. 3 : SEQ ID No.1: DNA sequence corresponding to the IND S1 sequence, which is the isolated genomic sequence of the inducible lucerne promoter PMs PR10-1.
Restriction sites: E=Eco RI, B=Bam HI.
The values indicated in the figure are expressed in kb (kilobases).
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLE 1
Production of Genomic Clones Comprising Regulatory Sequences of Lucerne PR Protein Genes
Production of a Probe for the Purpose of Finding the Promoters (cf. FIGS. 1 and 1 a )
The incompatibility response (hypersensitivity reaction: HR) which is obtained in the lucerne ( Medicago sativa ), and Pseudomonas syringae pv pisi host/parasite relationship made it possible to construct a cDNA library. It was prepared from messenger RNAs which were extracted and purified from the region adjacent to the necrosis caused by the bacterial infection. The samplings of plant material were carried out 6 hours after infiltrating with the bacterial suspension.
In leguminous plants, PR proteins are known to have conserved motifs; this made possible the synthesis of oligonucleotides corresponding to these motifs, which were defined on the basis of sequencing which had already been carried out on pea and soybean PR proteins. A PCR amplification made it possible to obtain a radioactive probe, which was then used to select transcripts from the cDNA library. Among these, one of the clones: cDNA-PR7, was adopted since, after sequencing, it exhibited 87% homology with the genes encoding the pea and soybean PR proteins. The analysis showed that it in fact corresponded to a gene encoding a class 10 PR protein according to the VAN LOON et al. (1994) classification. It was designated Ms PR10-1 ( Medicago sativa class 10 PR protein, clone 1).
A control, which was carried out in lucerne by Northern blot, showed that the corresponding transcript began to accumulate 3 hours after the infection in the case of the incompatibility response, went through a maximum between 24 and 48 hours and decreased slowly from 72 hours onwards.
This fragment is characterized by the existence of an internal Bam-BI site (marked with a B in FIG. 1) which delimits two portions:
the one, termed 5′, of approximately 340 bases, includes the region upstream of the ATG (transcribed but untranslated) and a downstream sequence corresponding to 306 bases,
the other, termed 3′, corresponds to the end of the coding portion, i.e. 165 bases, and to the untranslated 3′ region, i.e. 186 nucleotides from the stop codon to the start of the poly A.
Isolation of Genomic Clones Comprising PR Protein Promoters
Isolation of genomic clones
A lucerne genomic library, prepared in EMBL4 (titer: 7×10 8 p.f.u. (plates forming unit)·ml −1 ), was used on this occasion, and 6×10 5 p.f.u. were plated out. The 5′ fragment of Ms PR10-1 (cDNAPR7) was used as a probe to screen this library and 45 clones gave a signal, which was strong for 13 of them. The restriction mapping and hybridizations, which were carried out with the 5′ and 3′ fragments of Ms PR10-1, made it possible to conclude that there were 7 distinct clones (cf. FIG. 2 ). The comparison of the sizes of the 7 clones (9.3; 6.5; 6.1; 5.8; 4.8; 4.2; 2.2 kb) obtained from the screening of the library with that of the bands detected on Southern blot of lucerne genomic DNA showed good agreement between these two types of experimental data (cf. FIG. 2 ). It was thus possible to deduce therefrom that the genes encoding the PR7 protein corresponded to a small multigenic family.
The fragments (Eco-RI/Eco-RI sites) of these clones (apart from clone C12) were then subcloned in whole or in part, and sequencing was undertaken.
Sequencing carried out
One clone was chosen to be sequenced first, clone C15 (cf. FIG. 1 a ).
The initial sequencing work demonstrated the presence of an intron of approximately 315 nucleotides in the open reading frame of the gene encoding the PR protein. The clone being studied was then analyzed after digestion with Bam HI (cf. FIG. 1 a ). Clone C15: 6.1 kb.
The analysis of the clone by Eco RI and Bam HI made it possible to obtain two fragments, E-B (approximately 2.4 kb) and B-E (approximately 3.7 kb). After sequencing and comparing the coding sequence (interrupted by a 600-nucleotide intron) with that of Ms PR10-1 (cDNA-PR7), it appeared that this genomic clone was absolutely identical to this reference cDNA.
Analysis of the expression of the isolated clones in the lucerne-Pseudomonas system
The experiments related to clone C15, using the 5′ extension technique in order to determine the messenger molecules which were in fact transcribed during the induction of the defense reactions. This technique also has the advantage of making it possible to locate the transcription start site. The results showed that clone C15 was in fact expressed during the induction of the defense reactions in the leaves, during the lucerne/Pseudomonas interaction.
EXAMPLE 2
Genetic Transformations Carried Out in Order to Verify the Promoter Activity of the Isolated Clone
Promoter Regions Used
Two promoters were adopted for these verification transformations: a control promoter and the PR promoter which was isolated from the lucerne genome and which was derived from C15 (corresponding to the promoter PMs PR10-1).
Ca MV-35S promoter
This promoter, which is a so-called constitutive promoter, is conventionally used. It corresponds to the sequence for regulation of the transcription of the gene of the 35S RNA subunit of the cauliflower mosaic virus (CaMV). The promoter region which was used to prepare the construct with the gus reporter gene in fact corresponds to a fraction of this promoter, which was re-isolated in the form of an Eco RI/Bam HI fragment from the plasmid pDH51 (PIETRZAK et al. , 1986).
PR promoter
The promoter region of genomic clone C15 was studied. This promoter was subsequently termed PMs PR10-1.
PMs PR10-1:
It is derived from the 2.4-kb Eco RI/Bam HI (E/B) fragment of clone C15 FIG. 1 a ) The integration of this fragment into the binary plasmid, upstream of the reporter gene (see below), was made difficult since there was no restriction site in clone C15 between the TATA box (start of transcription) and the ATG (start of translation). Deletion experiments were therefore carried out until a fragment of approximately 1.5 kb (IND S1 sequence) was obtained. Another Bam HI site was then added, by blunt-end ligation, to the fragment thus obtained in order to enable its insertion upstream of the various coding sequences subsequently used. This fragment thus comprises, with reference to the cDNA which was used to clone it, and besides the upstream promoter region: 39 terminal nucleotides of the 5′UTR (UnTranslated Region) of the Ms PR10-1 gene, located 10 bp from the ATG start codon, the ATG of the Ms PR10-1 gene and a short fragment of its coding region (10 bp), immediately upstream of the integrated Bam HI site. Taking into account the cloning sites, the promoter thus constructed has a potential ATG which might lead to the presence of two ATG codons, a short distance from each other, when constructing chimeric genes. There might then be a risk of modifying the coding frame of the gene used (reporter gene or gene of agronomic interest).
For the transformation experiments with the reporter gene, PMs PR10-1 (PRI) was used in unmodified form after having been cloned into the STRATAGENE Bluescript pSK+/− plasmid. It was possible to re-isolate it in the form of an Eco RI/Bam HI fragment of 1.5 kb approximately.
Plasmids used
a) p35S-gus intron (VANCANNEYT et al., 1990)
This plasmid is a derivative of pBin19 (BEVAN, 1984) and, as such, possesses the right and left borders of the binary plasmids, enabling the insertion of the portion contained between these borders into plants using agrobacteria.
The development of the gus-intron (intron derived from the potato LSI gene) reporter gene made it possible to eliminate the false positives (in particular in transient expression) which were due to contaminating agrobacteria. They are unable to splice the introns.
Conventionally, this gene encoding a β-glucoronidase makes it possible to obtain a blue coloration when using a specific substrate (5-bromo-4-chloro-3indolyl-β-glucuronide). This blue colour then indicates that the analysed plant has been transformed and, as a consequence, that the coding sequence of the gene corresponding to the enzyme has been transcribed and, therefore, that the promoter which controls it has been induced.
b) pPR97
This plasmid was constructed by one of the laboratories participating in the project in order to test the effectiveness of promoters (P. RATET, ISV, cited in SZABADOS et al., 1995). It has, in particular, the advantage of possessing a multiple cloning site, which allows transcriptional fusion with the coding frame of the gus gene ( E. coli uid A) containing the LSI intron. It also possesses some of the properties of the preceding plasmid p35S-gus-intron (borders for integration into the plant genome, selection gene affording resistance to antibiotics such as neomycin: npt II gene).
The activity of the promoter can be revealed and measured by histochemical and enzymatic assays such as GUS.
pPR97 derivatives
Two main constructs were made and subsequently used for transforming model plants.
a) pPR97-35S
The 35S promoter, cloned into the plasmid pDH51 (cf. paragraph below concerning the strains of agrobacteria), was excised and inserted into the multiple cloning site of pPR97, upstream of the reporter gene, in the form of an Eco RI/Bam HI fragment. This plasmid is both a positive control for demonstrating that the construct is functional, and a reference, since the 35S promoter was placed in the same environment as the promoter isolated from the PR protein clones.
b) pPR97-PMs PR10-1
The 1.5 kb were inserted into the same cloning site as that defined above, in this case too in the form of an Eco RI/Bam HI fragment.
c) pG3-3
This made it possible to obtain a strong positive control via a histochemical assay and an enzymatic assay by cloning two 35S promoters in an inverted tandem. The activator sequences of the promoters then act synergistically. The coding frame of the gus-intron gene was then placed under the control of one of the two 35S promoters.
The strains of agrobacteria prepared
The various plasmids were used to transform competent E. coil strain DH5α bacteria by heat shock in calcium chloride medium. After selecting the transformed bacteria on medium containing antibiotic (kanamycin) and using a miniprep to verify that they were recombinant, they were used to transfer the recombinant plasmids into strains of agrobacteria by triparental conjugation using the E. coil strain HB101 which harbors the autotransferable plasmid pRK2013 (DITITA et al., 1985).
Two strains of agrobacteria were adopted: EHA 105, which is a disarmed Agrobacterium tumefaciens and which enables the regeneration of transformed plants (stable transformations), and A4TC24, which is Agrobacterium rhizogenes and which was used to obtain the hairy root reaction and composite plants whose roots are transformed but which otherwise have a phenotype which is identical to that of the original phenotype.
Genetic transformations on model plants
Two types of transformation (transient and stable) were carried out using three plant models, Nicotiana benthamiana, Medicago truncatula and Lotus corniculatus.
The results presented will be mainly those obtained with N. benthamiana.
Transient transformations
This first series of experiments was carried out in order to allow rapid verification of the functionality of the constructs prepared with the gus gene in eukaryotic cells.
N. benthamiana leaves were thus excised and cocultured on agar medium with the various derivatives of the strain EHA 105. Histochemical assays were then carried out 48 hours after the transformation, and then examined after overnight incubation (12 h).
The control plasmids p35S-gus-intron and pPR97-35S gave a GUS coloration which was positive although weak with the second plasmid.
This weak reactivity without doubt comes from a construction problem, since a portion of the polylinker had to be retained in the vicinity of the transcription start site and of the ATG of the gus gene. Since this polylinker comprises a repeat sequence it can interfere with the transcription of the gene.
The construct pPR97-PMs PR10-1 showed gus gene activity which was similar to that of the 35S gus-intron positive control. This promoter, which was expected to be inducible, thus exhibited an effect which was comparable to a constitutive promoter in this case.
This result can be explained as being the consequence either of the bacterial infection or of the wounds inflicted on the leaves during sampling or during culturing. Since the first hypothesis cannot be verified, the experimental protocol was modified in order to decrease the stress caused to the explants (increase in the osmolarity of the coculture medium using sucrose concentrations of 10 to 30 g.1 −1 , application of a more or less high vacuum range: from 10 to 80 mm of mercury of relative vacuum and creation of more or less severe lesions on the leaves with significant or moderate crushing of the epidermis).
The results showed that as the pressure increased, the number of transformed cells increased. However, a compromise should be found in order to obtain stable transformations, since the many transient transformations obtained in this case frequently turn out to be subsequently lethal for the cells. They are then incapable of giving rise to cali and thus of regenerating shoots and then plants.
Moreover, the inducible nature of the promoter is in part confirmed since, while the coloration due to the 35S gus-intron construct can be detected up to 5 days after coculturing, that obtained with pPR97-PMs PR10-1-gus-intron appears more rapidly at 48 hours but then subsides very rapidly.
Stable transformations
a) Tobacco: N. benthamiana
A series of transformations was carried out with pPR97-35S, pPR97-PMs PR10-1 and PG3-3. A considerable number of plantlets was obtained with this series of transformations. For each of the plasmids used, an attempt was made to obtain at least 7 acclimatized plants. However, this was not possible for p35S-gus-intron, with which only 5 plants were regenerated and acclimatized. The results obtained are compiled in Table 1.
TABLE 1
Stable transformations obtained in N. benthamiana by transformation
with the Agrobacterium tumefaciens strain EHA 105 and its derivatives.
Cali/explants
Shoots
Plantlets
Constructs
cultured
obtained
In vivo
Accl
p35S-gus-intron
10 (45)
6 (1)
5
5
pPr-97-35S
115/122
23
13
12
gus-intron
pPR97-PMs PR10-1
135/139
27
20
7
gus-intron
pG3-3-35S as an
not evaluated
37
28
20
inverted tandem
(strong promot.)
Legend to Table 1
The results are expressed as amount obtained.
Ace.: acclimatized plantlets.
Number of shoots per explant: the number in brackets corresponds to the number of shoots obtained at one month for the first series. For this series (comprising the 35S gus-intron constructs), the cali were left longer on the culture medium in order to obtain a maximum of shoots and thus of plants to acclimatize. For the second series, after one month, a sufficient number of shoots had been obtained and the experiment was then stopped.
Genetic transformations: they are carried out conventionally on 1-cm 2 pieces of leaf lamina which are submerged in the Agrobacterium suspension for 30 seconds and then cocultured for 48 hours before being subcultured onto agar medium for cell division and caulogenesis: M. S. (MURASHIGE and SKOOG, 1992), 0.1 mg×1 −1 NAA (naphthaleneacetic acid), 1 mg×1 −1 BAP (benzylaminopurine), 400 mg×1 −1 cefotaxime (elimination of the agrobacteria) and 70 mg×1 −1 kanamycin (agent for selecting transformed cells). As soon as the first shoots have appeared (approximately one month after coculturing), they are placed on rooting medium which is identical to the former except that it does not contain plant hormones.
The analysis of the results, in terms of the expression of the gus-intron gene, depending on the nature of the promoter which is located upstream of the coding frame of the gene, show that the promoter PMs PR10-1 gives the best results of all of the promoters tested. A more detailed analysis is presented below.
Properties of the promoter PMs PR10-1
Plasmid pPR97-PMs PR10-1-gus-intron
This promoter gave the best results, with differences in constitutive expression of the gus gene depending on the organs tested.
a) Activity in cali
Strong constitutive expression was found. A few minutes of incubation were sufficient to obtain a positive histochemical assay. The promoter is thus strongly induced in this type of material, this being in agreement with the results obtained by VAN LOON (1985). Cali which are cultured in vitro are in a state of stress and, under these conditions, PR proteins are expressed.
b) Activity in acclimatized whole plants Roots
The promoter is induced and the histochemical assay is positive after 2 hours of incubation (as against 5 hours with the 35S promoter). The activity of the gus gene is not uniform in tobacco roots, only the epidermis of the old parts and the apical meristem gave the blue coloration which is characteristic of the assay. According to the literature, defense gene activity in the roots is also observed under conventional conditions.
Flowers
A strong constitutive activity was found in the flowers and, more particularly, in the anthers and the pollen of all the tobacco plants which were transformed with this construct. Gus gene activity was also detected in the trichomas of the sepals and, more weakly, in the petals. These results are also in agreement with those of VAN LOON (1985), which indicate defense gene expression in the floral parts.
Leaves
Weak constitutive gus activity was observed in the trichomas of young leaves of adult plants. In tobacco, the large-leaved rosette stage corresponds to the juvenile stage and the aging stage to that of the formation of seeds. This weak activity was predominantly observed in the multicellular trichomas. To our knowledge, the expression of a PR protein in such structures has never been described.
Constitutive inducing activity of the isolated promoter PMs PR10-1 is thus possible in the trichomas of tobacco leaves (3 plants out of 7), but it appears to be under the influence of the development stages.
In the absence of induction by a pathogen, the activity of the promoter in tobacco is thus limited to the root, to the floral parts (anthers and pollen) and to a few cells of the aerial part (essentially trichomas).
EXAMPLE 3
Other Plant Species Transformed
Medicago truncatula
For this species, an attempt was made to produce composite plants, i.e. plants which possess both a wild-type aerial part (not genetically transformed) and transformed roots.
Young germinations were used. After development of the main root, the hypocotyls, which had been excised, were soaked in a suspension of Agrobacterium tumefaciens EHA 105 harboring either the plasmid p35S-gus-intron or the plasmid pPR97-PMs PR10-1-gus-intron, so as to subsequently obtain newly formed transformed roots. After one week, roots were obtained and a GUS histochemical assay was carried out. For this experiment, the control consisted of young germinations which were treated in an identical manner to the previous batches (hypocotyls excised, but not soaked in the suspension of agrobacteria).
All the explants of the control batch formed new roots within one week; by contrast, only 50% reacted in the case of the batches treated with the agrobacteria. Whatever the treatment, no root gave a positive response to the GUS assay. Conversely, although necrosed, the base of the hypocotyls in the treated batches often reacted to give a blue coloration (presence of transformed cells). The necrosed part of the explants was then excised, and they were set to rooting again. 50% then developed newly formed roots, some of which proved to be positive in the assay in a few regions.
Chimeric roots (transformed and untransformed cells) were thus obtained, the transformed parts corresponding to cell lines having integrated the construct into a basal stem cell.
The two constructs tested, p35S-gus-intron and pPR97-Pms PR10-a1-gus-intron, gave these transformed root cell lines in 3 and 2 explants, respectively, out of the 6 which were subjected to experiment for each batch.
Although the experimental model is not suited to the study being pursued (study of the expression of PR proteins in the phenomenon of nodulation by Rhizobium), it nevertheless demonstrated that the promoter PMs PR10-1 is just as functional in this plant as in the original plant ( Medicago sativa ).
Lotus corniculatus
In this case too, the aim of the experiment was to study the induction of the promoter in nodulation by the symbiotic bacterium Rhizobium meliloti NZP 2037 (PETIT et al., 1987). Composite plants were thus produced by transforming hypocotyl cells of young Lotier germinations with Agrobacterium rhizogenes strain A4TC24, so as to obtain the hairy root phenomenon (hairy root phenotype). Once this had developed, the main roots were excised and the plantlets were placed in liquid medium to increase the development of the phenomenon. Once the plants were acclimatized, the study of the induction of the promoter(s) was carried out by placing the plantlets under nodulation conditions (BLONDON, 1964). The two promoters which were used for the study were the same as those used in the experiment carried out with M. trunculata: 35S and PMs PR10-1. Using these two constructs, less than 10% of the roots having the hairy root phenotype exhibited roots which were positive in the GUS assay. In general, the roots with this phenotype gave fewer nodules than the control roots.
For those obtained with the construct comprising the 35S promoter, only the nodules exhibited a positive response in the GUS assay, whereas for the other (promoter PMs PR10-1), the coloration developed over the whole of the root, apart from the secondary root initiation point. Moreover, this latter construct did not make it possible to obtain nodules on the hairy root-derived roots in interaction with Rhizobium meliloti.
EXAMPLE 4
Study of the Hypersensitivity Reaction of Tobacco Transformed with the Constructs which Use the Promoter of the Lucerne PR Gene and the gus-intron Gene
Hypersensitivity reaction in N. benthamiana transformed with the constructs which combine the promoter of the lucerne PR gene and the gus-intron gene.
Hypersensitivity reaction (HR) assay
The hypersensitivity reaction (HR), developed in the N. benthamiana/Pseudomonas syringae pv. pisi interaction, was used in this study. Transformed tobacco plants, which had incorporated into their genome the various inserts of the plasmids p35S-gus-intron and pPR97-PMs PR10-1-gus-intron, were acclimatized and then infiltrated with a suspension of P. syringae (ESNAULT et al., 1993) at a concentration of 10 9 bacteria per ml. The solution was injected into the lamina using a hypodermic syringe. Using such a model, the HR-type reaction is regarded as being fully developed after 48 hours. The leaves, which had been infiltrated with the bacterial suspensions, were removed at 24, 48 and 96 hours after inoculation in order to evaluate, by GUS histochemical assay, the induction of the various promoters studied. The analysis of a possible systemic response was also evaluated, using the same histochemical assay, on leaves located below the infiltrated leaf.
Study of the induction of the promoters under HR-type reaction conditions
a) 35S constitutive promoter
In the case of the 35S constitutive promoter (plasmid pG3-3, for example), the inoculation with P. syringae did not modify the response in the assay, and this was evident after a few minutes of incubation. The infiltration with the bacteria does not, therefore, adversely modify the constitutive glucoronidase activity which is obtained with the 35S promoter.
b) Promoter of the PR protein gene: Promoter PMs PR10-1
As shown in Table 2, this promoter is readily inducible by pathogen attack. At 24 hours, the HR-type reaction is not yet fully developed (48 hours for complete display); however, the GUS assay is already positive. In the case of the young transformed tobacco plants which were obtained, the coloration is weak and is located predominantly in the lamina of the infiltrated leaf.
With regard to the systemic response, the response in the leaf which is below the infected leaf, the coloration is only present in the lamina. The adult (with developed stems but not yet having flowered) and juvenile (rosetted) tobacco plants have the same type of response, with weak gus gene activity, as determined by the histochemical assay.
For the older tobacco plants, which are in flower or are bearing seeds, the coloration obtained in the assay is more intense, especially in the veins and the trichomas of the infected leaf, and, in the case of the systemic response, is only in these tissues.
Differences in expression of the reporter gene are thus demonstrated depending on the age of the plant. This response, which is dependent on the development stage, was found in most of the studies carried out on plant PR proteins. The induction of the promoter PMs PR10-1 is a transient phenomenon, since the expression of the reporter gene is no longer visible 96 hours after the inoculation with the bacteria.
The induction is not limited, either, to the HR-type reaction obtained in the plant/bacterium interaction. The same type of response was obtained with the construct PMs PR10-1-gus-intron when one of the plants became infected with a fungus. A homogeneous expression of the gus gene was then visible over the whole of the infected leaf, apart from the region of contamination which, itself, was necrosed.
TABLE 2
Induction of the various promoters studied during the
HR-type reaction between N. benthamiana and P. syringae.
24 h after inoculation
96 h after inoculation
Infiltrated
Leaf
Infiltrated leaf HR-
Construct
leaf
below
type reaction
PMs PR10-1
6/7
6/7
0/3
pG3-3 (35S)
3/3
3/3
0/3
Legend to Table 2
The results are presented as the number of plants responding positively in the GUS histochemical assay with respect to the number of plants analyzed.
Quantitative Expression of the gus-intron Gene Under the Control of the Various Promoters
The method is based on an enzymatic assay.
It uses:
a) a crude extract of the enzyme encoded by the gus gene, which is obtained from transformed tobacco plants, and
b) a substrate, p-nitrophenylglucoronide. The rate of hydrolysis of the substrate is monitored using a spectrophotometer and is related to the total amount of proteins in the extract. The method requires, however, the presence of a strong promoter upstream of the gus gene, since it is relatively insensitive.
Consequently, it was not used for assays in which 12 or more hours of incubation with the substrate used for the histochemical assay (X gluc: 5-bromo-4-chloro-3-indolyl-β-glucoronide) were required.
Under these experimental conditions, the 35S promoter, placed in the plasmid pG3-3, gave a rate of substrate hydrolysis (expressed in arbitrary units) which was 5 times higher than with the promoter PMs PR10-1, itself placed in the plasmid pPR97. On the other hand, the promoter PMs PR10-1 gave a stronger expression of the gus gene than did the 35S promoter, when this 35S promoter is placed in the plasmid p35S-gus-intron. Specifically, in this latter case, no substrate hydrolysis was detected.
Similarly, it was not possible to obtain spectrophotometrically detectable values with the other constructs.
Conclusions
The promoter PMs PR10-1, which is isolated from M. sativa (lucerne), entirely satisfies the characteristics which are required for its use as a sequence for regulating a gene of agronomic interest which is able to act in plant defense against pathogen attack. It is inducible by a pathogen (bacterium and fungus), this being a process which can take place including in a heterologous system, tobacco. It also has a weak constitutive activity, mainly in the roots, including in other heterologous systems ( M. truncatula and L. corniculata ).
Another constitutive activity, which has not yet been explained, has also been noted in the embryonic cali of lucerne.
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1
1
1392
DNA
Medicago sativa
1
gaattcttca aaaaaaaagt tgcccttgag aaactaataa gttaataaac taagacctct 60
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gaattaattt gatactgatg atttttaaag ctgtagatat ttacgtattt agttaaaaaa 240
atacaattat tatatattta attggtgtgt ctattcaagt gtttaactta agttgaggtt 300
tattcttatg ttactaagtt ggagtggaga agaagactat ttgcttggga ggaggaacgc 360
ccagtagaat gtgttattat tttttatttt tttgtaagga gtagagtgtg ttatgttgct 420
tgaataattt ttttttgtag gataatgtat tagacaaata aatttggaaa cacgaccctg 480
tcaaagagta cacggtaaag ggggtggtat acaaaagagt gcgtcgctct attcttcagg 540
tcatttggtt tgctacagtt taggaaattt gggaggaaag aaataacaga ctgtataacg 600
tcaaagaatg ctcggttatt caggtggtag ataagattaa gtttcttgct tttgcatggg 660
tgaaggcaaa gtttgcttct cttccattca attaccatgg gtggcggctt agtccgttta 720
ccatactgga cataggctaa gagtttttct tttctcgttt ttccattaca agttctttat 780
gtaaatactg ttttgacttt ggtgttcttc ccttagtaca ccttgtgcta ggaaggacta 840
ttttgatttg gtaatatatt tcattttaac ctcttaaaaa aaaatcagga aaagaaaaag 900
ataaaggtcg gaagtgttac ctgattataa aataaatgat taaattgaaa ataaagataa 960
ataactaaaa tgttttctat aattaagtta agagatgaaa tatgtaattt tcccaattat 1020
atattatgta agtttttatt tattttatat acgttgtttt gctttgaaat ttgagtggtc 1080
ttggaggaga gaaaaacaaa agagaaaaga aaaattaata gtagatgcaa taattttgtt 1140
agtccaaata ataatatagt tttctttaaa aataatatca tccaaactca tacattaaaa 1200
atattattca aatttatgtc acgtcacaat gagaaaaaat ggcccaacga ccttgtatta 1260
cacatcatcg tcatcatcat ctaaagtcta aacaatacat cttcttttcc tataaataca 1320
agactcaact ccactcataa atcacacagg caaacaatta acttcttaat agtttgttat 1380
ttcacacatt ag 1392
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The invention concerns a set of plant promoters inductible by biotic or abiotic stresses, in particular by pathogens, their use, expression vectors comprising said promoters and a gene of interest, cells and/or plants transformed by said vectors. The invention also concerns methods for obtaining said cells and plants, said transformed plants with improved resistance to said pathogens.
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FIELD OF THE DISCLOSURE
[0001] The present disclosure relates in general to apparatus and methods for introducing fluids into a casing string or other tubular element during well construction operations, and for removing fluids from the casing string. In particular, the disclosure relates to apparatus and methods for introducing a fluid such as drilling mud or cement slurry into a casing string at a selected depth by means of a tubular inner string.
BACKGROUND
[0002] Typical construction of an oil or gas well includes the operations of assembling a casing string, inserting the casing string into a wellbore, and cementing the casing in place in the wellbore. Casing assembly involves connecting multiple individual lengths of pipe (or “joints”) to form an elongate casing string. Threaded connections are usually used to join the individual lengths of pipe, requiring the application of torque to “make up” the connections, or to “break out” the connections should the string need to be disassembled. After a wellbore has been drilled to a desired depth into a subsurface formation, by means of a rotating drill bit mounted to the end of a drill string, the drill string is withdrawn and the casing string is then inserted essentially coaxially within the wellbore.
[0003] In the alternative method known as casing drilling (or “drilling with casing”), the wellbore is drilled with a drill bit mounted to the bottom of the casing string, eliminating the need for a separate drill string. After the well is drilled, the casing remains in the wellbore. As used in this patent document, the term “drill string” is to be understood, in the context of the drilling phase, as referring to the casing string for purposes of well construction operations using casing drilling methods.
[0004] During the drilling phase of well construction, a selected drilling fluid (commonly called “drilling mud”) is pumped under pressure downward from the surface through the drill string, out through ports in the drill bit into the wellbore, and then upward back to the surface through the annular space that forms between the drill string and the wellbore (due to the fact that the drill bit diameter is larger than the drill string diameter). The drilling fluid, which may be water-based or oil-based, carries wellbore cuttings to the surface, and can serve other beneficial functions including drill bit cooling, and formation of a protective cake to stabilize and seal the wellbore wall.
[0005] Once the well has been drilled to a desired depth and the casing is in place within the wellbore, the casing is cemented into place by introducing a cement slurry (commonly referred to simply as “cement”) into the wellbore annulus. This is typically done by introducing an appropriate volume of cement into the casing string (i.e., a volume corresponding to the volume of the wellbore annulus), and then introducing a second and lighter fluid (such as drilling mud or water) into the casing under pressure, such that the second fluid will displace the cement downward and force it out and around the bottom of the casing, and up into the wellbore annulus. In the typical case, this operation is continued until the cement has risen within the wellbore annulus up to the top of the casing. Once thus cemented, the casing acts to structurally line the wellbore and provide hydraulic isolation of formation fluids from each other and from wellbore fluids.
[0006] In some applications it is desirable to introduce cement into the casing through a tubular “inner string” inserted into the casing bore and arranged to extend from the proximal (i.e., upper) end of the casing string to a selected depth, typically near the distal (i.e., lower) end of the casing string or near what is referred to as the “casing shoe”. The inner annulus between the inner string and casing is left fluid-filled and sealed near the proximal end of the casing so that cement pumped through the inner string is then introduced into the casing near the shoe. The fluid filling the inner annulus tends to prevent cement flow up the inside of the casing and instead the cement is urged to immediately enter the casing wellbore annulus during pumping. This is known in the art as an “inner string cement job” and typically requires an adaptor nubbin, sealingly connecting between the casing and the inner string. On top-drive-equipped rigs, the adaptor nubbin also connects to the top drive, facilitating the functions of rotation and reciprocation during cementing to further promote distribution of the cement in the casing to the wellbore annulus.
[0007] It is increasingly common in the drilling industry to use top-drive-equipped drilling rigs instead of traditional rotary table rigs, and to install casing (an operation commonly referred to as “casing running”) and/or to drill with casing directly using the top drive. Casing running tools (CRTs), such as the “Gripping Tool” described in U.S. Pat. No. 7,909,120, connect to the top drive quill and support these well construction operations by engaging the upper end of the tubular string (i.e., drill string or casing string, as the case may be) so as to allow transfer of axial and torsional loads between the tubular string and the top drive, and to allow the flow of fluids (such as drilling mud and cement) into or out of the casing string through a central passage or bore in the tool. Such tools thus enable the top drive to be used for make-up and break-out of connections between joints of pipe, hoisting and rotation of tubular strings, casing fill-up, circulation of drilling mud, and cementing of casing.
BRIEF SUMMARY
[0008] The present disclosure teaches embodiments of cementing adaptor tools for sealingly connecting an inner string to the distal (lower) end of a CRT while also facilitating the functions of reciprocation and rotation, so that the CRT can be used to replace the function of the adaptor nubbin without the need to engage with the casing threads, thus providing a sealed flow path for cement into the inner string and thereby enabling the CRT to be used perform an “inner string cement job”. This has the advantages of exploiting the existing capacity of the CRT to grip and seal with the casing, obviating the need for an adaptor nubbin customized to the casing thread (and thus removing the risk of damage to the casing thread), and eliminating the need to rig down the CRT after running the casing to replace it with the adaptor nubbin, thus saving time and reducing risk of damage.
[0009] Cementing adaptors in accordance with the disclosure are provided with a swivel connection for limiting torque that will typically arise during rotation of the inner string casing assembly as a result of frictional interaction between the inner string and the casing as they are rotated in wellbores having at least some deviation from vertical, thus inducing lateral loading between the casing's inner surface and tubular inner string's outer surface. It will be apparent to persons skilled in the art that right-hand rotation of the casing relative to the wellbore will tend to cause left-hand torque to build toward the proximal (upper) end of the inner string, which torque tends to back off the connections between the joints comprising the inner string (which are normally provided as right-hand-threaded connections).
[0010] The swivel connection further limits the torque that might otherwise overload the CRT or the connection between the cementing adaptor and the CRT. It will be apparent to persons skilled in the art that the swivel may take various forms and use various means to transfer loads from the inner string to the CRT while minimizing friction in the connection. Such alternative means may include (without being limited to) plain bushings, rolling element bearings, and pressurized fluid chambers.
[0011] To provide further protection for the CRT and the cementing adaptor against the risk of overload from bending loads that might arise from lateral gravity loads on the inner string in applications such as slant drilling (or other operations tending to displace the inner string away from substantially concentric alignment with the casing), suitable centralizers can be mounted to the inner string elements to act between the tubular inner string and the inside of the casing at selected locations along the length of the inner string to adequately support the inner string to a depth sufficient to prevent excess bending at the attachment point to the CRT or at any point in the inner string. It will be apparent to persons skilled in the art that the length and lateral stiffness of the inner string elements connecting the centralizers to the cementing adaptor can be selected to minimize bending loads at the attachment point.
[0012] Cementing adaptors in accordance with the present disclosure also provide means for sealing the annular space between the outer surface of the inner string and the inner surface of the casing, to prevent fluid in this annular space from being displaced out of the casing when cement is being pumped down the inner string, such that the cement is urged into the annular space between the outer surface of the casing and the wellbore.
[0013] Alternative embodiments of cementing adaptor tools in accordance with the present disclosure may also be adapted for use in conjunction with a plug-dropping manifold tool. A plug-dropping manifold tool, as is known to the art, has means to provide a swivel fluid entry to an inner string bore or tool bore, plus means for releasing one or more plugs (which may be ball plugs, wiper plugs or other similar devices), and include means for positively indicating the dropping of such plugs, while facilitating the functions of reciprocation and rotation by providing means for transferring axial and torsion loads from a top drive to the various tubulars used in oil well drilling and construction. In such embodiments, the cementing adaptor is attached to the distal (lower) end of a CRT mounted to the distal end of the plug-dropping manifold tool. The bores of the CRT and the inner string cementing tool are sized and aligned so that plugs released from the plug-dropping manifold tool will pass through the cementing adaptor and the inner string to provide functions including:
[0014] separation of displacing fluids from displaced fluids;
[0015] positive wiping of the inner surfaces of the casing to further enhance complete fluid displacement; and
[0016] engagement with their intended targets located downhole from the inner string.
[0017] Downhole targets may include devices such as cement staging tools or subsea cementing wiper plug launchers where the casing wiper plug is carried at the distal end of the cementing string and launched when a dropped ball or dart is pumped down and into engagement with the device in a manner known in the art of well cementing. Cementing adaptor tools adapted for use with plug-dropping manifold tools provide the advantage of not having to rig out the CRT to launch plugs or to perform ball drops, and also facilitate side-entry fluid injection (mud or cement), which is desirable in cases where operators prefer not to have certain fluids or slurries (such as cement) run through the top drive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Embodiments in accordance with the present disclosure will now be described with reference to the accompanying Figures, in which numerical references denote like parts, and in which:
[0019] FIG. 1 is a cross-sectional view of an embodiment of a cementing adaptor tool in accordance with the present disclosure, shown fitted with a stab guide/thread protector to allow for normal casing running operations with the cementing adaptor attached.
[0020] FIG. 2 is a cross-sectional view of the cementing adaptor tool in FIG. 1 , shown as it would appear disposed between and attached to a casing running tool and an inner string.
[0021] FIG. 3 is a cross-sectional view of the assembly in FIG. 2 , disposed within a tubular casing string with the casing running tool grippingly engaging the casing string.
[0022] FIG. 4 is a cross-sectional view of an assembly generally as in FIG. 2 , but with an inner string centralizing pup mounted between the inner string and the lower end of the cementing adaptor tool.
DETAILED DESCRIPTION
[0023] FIGS. 1 through 4 illustrate embodiments of a cementing adaptor tool 100 in accordance with the present disclosure. Cementing adaptor 100 is of an elongate and generally cylindrical configuration, with a proximal (upper) end 101 that can be rigidly attached to a casing running tool (CRT) and a distal (lower) end 103 that can be rigidly attached to a tubular inner string. Cementing adaptor 100 is provided with an internal flow path FP and configured such that flow path FP will be continuous with and sealed to an internal flow path in the CRT after cementing adaptor 100 has been mounted to the CRT. This internal flow path FP generally runs the length of the tool and allows for flow of fluid from the CRT through the cementing adaptor from the proximal end to the distal end.
[0024] Disposed between the proximal and distal ends of cementing adaptor 100 is a swivel element which allows an inner string attached to the distal end of cementing adaptor 100 to rotate independently of the CRT, and to minimize torque build-up within the inner string and thus minimize torque transfer from the inner string to the CRT. The distal end of cementing adaptor 100 typically will incorporate the male end of a shouldering threaded connection designed to threadingly and sealingly engage the female (or box end) of an inner string (which typically will be made up from oilfield drill pipe). Cementing adaptor 100 further incorporates a casing seal assembly designed to seal the annular space between cementing adaptor 100 and a casing string.
[0025] Referring now to FIG. 1 , cementing adaptor 100 with a proximal (upper) end 101 , a middle interval 102 , and a distal (lower) end 103 is shown in cross-sectional view with a stab guide 110 attached to distal end 103 . Cementing adaptor 100 comprises an elongate and generally cylindrical carrier 120 , a generally cylindrical swivel element 140 , a generally cylindrical connector 160 , and a generally cylindrical casing seal assembly 180 . Carrier 120 extends between proximal end 101 and middle interval 102 of cementing adaptor 100 and has an upper end 121 , a middle interval 122 , and a lower end 123 , with middle interval 122 and lower end 123 being separated or demarcated by an annular shoulder rib 127 extending radially outward from carrier 120 . Swivel 140 is coaxially and rotatably disposed about middle interval 122 of carrier 120 , above shoulder rib 127 . A load thread 124 and a seal 125 are provided at upper end 121 of carrier 120 . A plurality of seal grooves 126 are disposed along the outside surface of middle interval 122 . Annular shoulder rib 127 defines an upward facing shoulder 128 and a downward facing shoulder 129 . Lower end 123 is formed with a plurality of seal grooves 130 .
[0026] In the illustrated embodiment, casing seal assembly 180 includes a packer cup 181 of a type common to many oilfield casing seal assemblies. Casing seal assembly 180 is coaxially carried by carrier 120 , and sealingly engaged with one or more of seal grooves 126 on middle interval 122 of carrier 120 . It is understood that the performance criteria for seal assembly 180 will vary depending on casing weights and pressure requirements and may be changed from job to job as required. It is also to be understood that various options exist for alternative casing seal arrangements, and that cementing adaptors in accordance with the present disclosure are not limited to the use of the illustrated casing seal arrangement or any other particular casing seal arrangement.
[0027] In the illustrated embodiment, swivel element 140 has an upper end 141 , a lower end 142 with a lower end face 147 , and an internal surface 143 defining a downward-facing annular shoulder 144 near upper end 141 . Threads 145 are provided in a lower region of internal surface 143 , and pins 146 are provided through openings in the cylindrical wall of swivel 140 below threads 145 . Upper end 141 of swivel 140 sealingly engages a seal groove 126 on carrier 120 above shoulder rib 127 . Downward-facing shoulder 144 is parallel and adjacent to upward facing shoulder 128 on shoulder rib 127 , Shoulders 128 and 144 are separated by and mutually abutted by a friction-reducing bushing 150 . Connector 160 has an upper end 161 , a lower end 162 , an inside cylindrical surface 167 and an annular upper face 168 at upper end 161 , and an outer surface 163 , with threads 164 on an upper region of outer surface 163 for mating engagement with threads 145 on swivel 140 . A plurality of pockets 165 are formed into outer surface 163 for engagement with pins 146 . Tapered threads 166 are provided on outer surface 163 at lower end 162 .
[0028] It to be is understood that cementing adaptors in accordance with the present disclosure are not limited to embodiments incorporating the illustrated shouldering threaded connection. Depending on the application, this style of connection to the inner string may be modified either by providing a different connector or by providing a crossover to adapt the tool to a different size or style of connection.
[0029] Inside surface 167 at upper end 161 of connector 160 sealingly engages seals 130 on lower end 123 carrier 120 , while thread 164 engages thread 145 on swivel 140 and pins 146 engage pockets 165 to prevent thread disengagement and to react any torque generated through friction on shoulder 144 . Upper face 168 of connector 160 abuts downward-facing shoulder 129 of carrier 120 . Stab guide 110 , with lower tapered face 111 , upper shoulder 112 , tapered internal thread 113 , and locking pins 114 , loosely threadingly engages tapered thread 166 on connector 160 . Locking pins 114 engage pockets 169 on lower end 162 of connector 160 to prevent thread disengagement and to react any incidental torque.
[0030] With reference now to FIG. 2 , cementing adaptor 100 is shown disposed between and rigidly attached to the lower end 201 of a casing running tool (CRT) 200 (such as, by way of example only, a “Gripping Tool” as described in U.S. Pat. No. 7,909,120) and the upper end 301 of an inner string 300 . Carrier 120 of cementing adaptor 100 is rigidly attached to and in sealing engagement with the inside surface 202 on the lower end of CRT 200 . In this embodiment, the attachment method is a threaded and pinned arrangement wherein axial load is carried by thread 124 on carrier 120 and the mating thread on CRT 200 , and torque is reacted in shear through a plurality of cap screws 203 in holes 133 on carrier 120 . A seal 125 engages a seal face 204 on CRT 200 to provide a continuous sealed bore through the CRT 200 and adaptor 100 . Still referring to FIG. 2 , tapered and shouldered thread 166 of connector 160 is shown engaged with a female tapered shouldering thread 302 on the upper end 301 of an inner string 300 , providing rigid attachment and sealing engagement.
[0031] Referring now to FIG. 3 , cementing adaptor 100 is shown disposed between and rigidly attached to lower end 201 of CRT 200 and upper end 301 of inner string 300 . CRT 200 is shown engaged with and gripping a casing string 400 . Packer cup 181 is shown engaged with the inner surface 401 of casing string 400 , sealing off the annular space below packer cup 181 between cementing adaptor 100 and inner surface 401 of casing string 400 from the annular space above packer cup 181 between CRT 200 and inner surface 401 of casing string 400 . As thus arranged, CRT 200 is able to hoist, rotate, and reciprocate the casing, with any incidental relative rotation as a result of the tumbling action of inner string 300 within casing 400 (such as in a deviated wellbore) being relieved through the action of swivel 140 . This arrangement thus facilitates and enables the functions required for running an inner string cementing job, including rotation and reciprocation of the casing string, taking into consideration the hoisting and torque capacities of both the system as a whole and its individual components.
[0032] Referring now to FIG. 4 , cementing adaptor 100 is shown disposed between and rigidly attached to lower end 201 of CRT 200 and upper end 301 of inner string 300 , with CRT 200 engaging and gripping casing string 400 , generally as seen in FIG. 3 . In this arrangement, however, an inner string pup 500 with a centralizing flange 501 is disposed between and attached to connector 160 and inner string 300 , and a side load bushing flange 190 is disposed between upward-facing shoulder 168 on connector 160 and lower end face 147 of swivel 140 . Both the outer diameter of bushing flange 190 and centralizing flange 501 are selected to be close to the minimum allowable casing diameter (or “drift”). The arrangement of these centralizing flanges prevents side loads induced by slant-drilling operations (or other forces tending to displace the inner string eccentric from substantially coaxial alignment with the casing) from overloading carrier 120 in bending, which would typically occur in the region of minimum section near upper end 121 of carrier 120 . It to be is understood that when significant side load is anticipated during an inner string cementing job, the axial spacing of these flanges can be selected in consideration of the compliance of both the cementing adaptor and the inner string, and in consideration of the clearance between the outer diameter of the flanges and the inner diameter of casing 400 , to prevent excessive bending stresses in cementing adaptor 100 and CRT 200 .
[0033] It will be readily appreciated by those skilled in the art that various modifications of cementing adaptor tools in accordance with the present disclosure may be devised without departing from the scope and teaching of the present disclosure, including modifications which may use equivalent structures or materials hereafter conceived or developed. It is to be especially understood that the disclosure is not intended to be limited to any described or illustrated embodiment, and that the substitution of a variant of a claimed element or feature, without any substantial resultant change in function or operation, will not constitute a departure from the scope of the disclosure. It is also to be appreciated that the different teachings of the embodiments described and discussed herein may be employed separately or in any suitable combination to produce desired results.
[0034] In this patent document, any form of the word “comprise” is to be understood in its non-limiting sense to mean that any item following such word is included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one such element.
[0035] Any use of any form of the terms “connect”, “engage”, “attach”, “mount”, or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the subject elements, and may also include indirect interaction between the elements such as through secondary or intermediary structure.
[0036] Relational terms such as “parallel”, “concentric”, and “coaxial” are not intended to denote or require absolute mathematical or geometrical precision. Accordingly, such terms are to be understood as denoting or requiring general or substantial precision only (e.g., “generally parallel” or “substantially parallel”) unless the context clearly requires otherwise.
[0037] Wherever used in this document, the terms “typical” and “typically” are to be interpreted in the sense of representative or common usage or practice, and are not to be understood as implying invariability or essentiality.
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A cementing adaptor includes a cylindrical carrier carrying a casing seal, a middle interval and a lower end separated by an annular rib, and a cylindrical swivel element disposed around and coaxially rotatable relative to the middle interval. A cylindrical connector has an upper end rotatably disposed around the carrier's lower end and non-rotatably connected to the swivel element, plus a lower end connectable to an inner tubular string. With the carrier's upper end connected to a casing running tool (CRT), this assembly can be disposed within a casing string with the casing seal engaging the casing and preventing fluid flow into the casing annulus below the seal when cement is pumped down the inner string, such that the cement is urged into the wellbore annulus. The swivel connection limits torque transfer that might otherwise overload the CRT or its connection to the cementing adaptor.
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CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of International Application PCT/EP2012/001288 filed Mar. 23, 2012, designating the United States and published on Oct. 4, 2012 as WO 2012/130418. This application also claims the benefit of the U.S. Provisional Application No. 61/467,422, filed on Mar. 25, 2011, and of the German patent application No. 10 2011 015 126.5 filed on Mar. 25, 2011, the entire disclosures of which are incorporated herein by way of reference.
BACKGROUND OF THE INVENTION
[0002] The invention concerns an aircraft tail region with a cooling system installed in the aircraft tail region, and a method of operating a cooling system installed in the aircraft tail region.
[0003] Fuel cell systems make it possible to generate electrical current with low emissions and high efficiency. At present there are therefore efforts to use fuel cell systems in various mobile applications, e.g., in automotive engineering or aviation, to generate electrical energy. For example, in an aircraft, replacing the generators which are currently used for on-board power supply, and are driven by the main engines or auxiliary power units (APUs), with a fuel cell system is conceivable. A fuel cell system could also be used for emergency power supply to the aircraft, and to replace the ram air turbine (RAT) which has been used until now as the emergency power unit.
[0004] As well as electrical energy, a fuel cell in operation generates thermal energy, which must be carried away from the fuel cell using a cooling system, to prevent overheating of the fuel cell. A fuel cell system which is used in an aircraft, e.g., for on-board power supply, must be designed so that it is capable of covering a high requirement for electrical energy. However, a powerful fuel cell from the point of view of generating electrical energy also generates a large quantity of thermal energy, and therefore has a high cooling requirement. Additionally, on board an aircraft many further technical devices, which generate heat and must be cooled to ensure safe operation, are provided. These technical devices include, for example, air-conditioning units or electronic control components of the aircraft.
[0005] Aircraft cooling systems which are currently used include air inlet openings, which are usually provided in the region of the aircraft outer skin, and which for example can be in the form of ram air inlets, and are used to convey ambient air as coolant into the aircraft cooling system. Cooling air which is heated by receiving heat from devices to be cooled on board the aircraft is usually carried back into the environment through air outlet openings, which are also provided in the region of the aircraft outer skin. However, air inlet openings and air outlet openings which are formed in the aircraft outer skin increase the air resistance, and thus the fuel consumption of the aircraft. Also, aircraft cooling systems which are supplied with cooling air via ram air inlets have high pressure losses, cooling power which is limited among other things by the maximum incoming air volume flow through the ram air inlets, and relatively high weight.
[0006] From WO 2010/105744 A2, an aircraft cooling system which is suitable for cooling a fuel cell system, and which includes a cooler with coolant channels through which ambient air can flow, is known. The coolant channels are formed in a matrix body of the cooler, the outer surface of which, when the cooler is fitted in an aircraft, forms an outer surface of the aircraft outer skin. In contrast, an inner surface of the matrix body, when the cooler is fitted in an aircraft, forms an inner surface of the aircraft outer skin. In flying operation of an aircraft equipped with the cooling system, the coolant flow through the coolant channels which are formed in the matrix body of the cooler is controlled so that the coolant enters the coolant channels which are formed in the matrix body in the region of the outer surface of the matrix body, and leaves the coolant channels which are formed in the matrix body in the region of the inner surface of the matrix body. The cooling air is carried out of the aircraft through an opening which is formed in the region of a transom of the aircraft. In contrast, in ground operation of the aircraft the coolant flow is controlled so that cooling air is fed in through the opening which is formed in the region of the transom of the aircraft. The cooling air then flows through the coolant channels which are formed in the matrix body of the cooler, from the inner surface of the matrix body in the direction of the outer surface of the matrix body.
SUMMARY OF THE INVENTION
[0007] This invention is based on the object of providing an aircraft tail region in which an energy-efficient aircraft cooling system which can be operated with low noise and is also suitable for carrying away large thermal loads from a heat generating device, e.g., a fuel cell system, on board the aircraft, is installed. The invention is also based on the object of giving a method of operating such an aircraft cooling system installed in an aircraft tail region.
[0008] An aircraft tail region according to the invention includes a cooling system installed in the aircraft tail region, with a cooler which forms a section of an outer skin of the aircraft tail region. Preferably, the cooler is arranged in a lower shell region of the aircraft tail region, said lower shell region facing the ground in operation of the aircraft tail region. The cooler has a shape, size and structural properties which make it possible to use the cooler as an aircraft outer skin section. In particular, the cooler comprises a material which makes it possible to use the cooler as an aircraft outer skin section. For example, a main body of the cooler may comprise a metal or a plastic material, in particular a fibre-reinforced plastic material. The cooler is preferably mounted detachably, meaning that the cooler is preferably mounted on corresponding supporting elements, e.g., components of the aircraft structure, and/or fixed to sections of the aircraft outer skin adjacent to the cooler, so that the cooler can be at least partly detached from its position comparatively easily. In this way, components which are arranged within the aircraft tail region can be made conveniently accessible for replacement or maintenance purposes. Fitting an additional access door, which makes access to the interior of the aircraft tail region possible, is then unnecessary. This makes it possible to achieve additional weight savings.
[0009] The cooler includes coolant channels allowing a flow of ambient air therethrough, and extending from a first surface of the cooler, which forms an outer surface of the aircraft outer skin, to a second surface of the cooler, which forms an inner surface of the aircraft outer skin. The cooler may be provided only with coolant channels, through which a coolant of a heat-generating device on board the aircraft may be fed for direct cooling. Alternatively, however, the cooler may also be in the form of a heat exchanger. In the cooler, as well as multiple coolant channels, multiple thermal transfer medium channels, through which a thermal transfer medium to be cooled can flow in operation of the cooler, may be formed. If coolant is carried through the coolant channels, the cooling energy contained in the coolant can be transferred to the thermal transfer medium to be cooled, so that the thermal transfer medium is cooled. Finally, using the cooler both as a heat exchanger and to carry coolant for direct cooling of a heat-generating device on board an aircraft is conceivable. Then, when the coolant flows through the cooler, it can deliver cooling energy to a thermal transfer medium, and additionally, before or after flowing though the cooler, be used for direct cooling of a heat-generating component or heat-generating system on board the aircraft.
[0010] The cooler may also include multiple ribs, which extend from the first surface of the cooler. The ribs are preferably adapted to act as flow baffles, i.e., to guide an airflow which flows over the first cooler surface, e.g., in flying operation of the aircraft, in a desired direction over the first cooler surface. A further advantage of the version of the cooler with multiple ribs extending from the first cooler surface is that the ribs protect the cooler, and in particular the first cooler surface, from external influences. To minimize the frictional resistance caused by the ribs in flying operation of the aircraft, and to make even flow over the first cooler surface possible, the ribs are preferably aligned essentially parallel to flow lines of an airflow which flows over the first surface of the cooler in flying operation of the aircraft. The ribs may also have a contour which is curved in the direction of the first cooler surface. The ribs which extend from the first cooler surface may comprise the same material as the main body of the cooler, but also of a different material. For example, the ribs may comprise a metal or a plastic material, preferably a fibre-reinforced plastic material. For example, in the aircraft tail region according to the invention, a cooler described in WO 2010/105744 A2 can be used.
[0011] The aircraft tail region according to the invention also includes a fan system, which is adapted to convey ambient air through the coolant channels of the cooler at least in specified operating phases of the cooling system. The operation of the fan system may be controlled by means of a suitable control unit. The control unit may be adapted to control the fan system so that the fan system, in particular in ground operation of an aircraft equipped with the aircraft tail region, conveys ambient air through the coolant channels of the cooler. Thus even in ground operation of the aircraft, proper flow through the coolant channels of the cooler and consequently proper functioning of the cooling system are ensured. However, if required, the control unit may control the fan system even in flying operation of the aircraft so that it conveys ambient air through the coolant channels of the cooler.
[0012] Finally, the aircraft tail region according to the invention includes a first opening which is formed in the outer skin of the aircraft tail region, and which allows, in conveying operation of the fan system, ambient air which is supplied through the coolant channels of the cooler into an interior of the aircraft tail region to be discharged back into the aircraft environment.
[0013] The aircraft tail region according to the invention has the advantage that the cooler replaces a component which is present in the aircraft tail region in any case, namely a section of the aircraft outer skin. The cooler thus requires no or, according to its thickness, only a little additional installation space. The cooler also causes a comparatively small additional weight. Finally, the cooler, compared with conventional systems, enables a multiplication of the area through which coolant may flow. In this way the cooler provides very high cooling power and also causes only very small pressure losses. Therefore, the cooler can be used in a specially advantageous manner on board an aircraft to carry away large thermal loads from a heat-generating device, e.g., a fuel cell system, very efficiently.
[0014] Preferably, the cooler forms a section of an outer skin of the aircraft tail region, said section being arranged at a first distance from a transom of the aircraft tail region. For example, the distance of the cooler from the transom of the aircraft tail region may be chosen so that the cooler is reliably outside an aircraft tail region section which could be affected by a tail strike (ground contact of the aircraft tail region when the aircraft takes off). The fan system is preferably arranged at a second distance from the transom of the aircraft tail region, the second distance being less than the first distance.
[0015] In a preferred embodiment of the aircraft tail region according to the invention, the cooler and the first opening which is formed in the outer skin of the aircraft tail region are positioned relative to each other so that at least in specified operating phases of the cooling system, ambient air is supplyable through the first opening into the interior of the aircraft tail region, and dischargeable back through the coolant channels of the cooler into the aircraft environment, driven by differential pressure. In other words, the cooler is preferably arranged in a region of the outer skin of the aircraft tail region onto which, in flying operation of an aircraft equipped with the aircraft tail region, a lower pressure acts than onto the first opening For example, the first opening may be arranged at a lower distance from the transom of the aircraft tail region than the cooler. In the case of such a version of the aircraft tail region according to the invention, in flying operation of the aircraft, pressure differences which are present in any case in the region of the aircraft outer skin can be used to convey the coolant through the coolant channels of the cooler and finally back to the aircraft environment through the first opening, which acts as a coolant outlet. The fan system can then be operated with less power at least in some operating phases of the aircraft cooling system, and consequently if required be designed to be less powerful and thus more compact and of less weight. However, at least it is unnecessary to operate the fan system always in the range of its maximum power, so that the lifetime of the fan system can be increased and its maintenance liability can be reduced.
[0016] The cooling system which is integrated in the aircraft tail region according to the invention can thus, e.g., under the control of the control unit of the fan system, be operated in various operating phases and different operating modes. For example, the control unit may control the coolant flow by corresponding operation of the fan system in ground operation of the aircraft, in such a way that the coolant flows through the coolant channels of the cooler from outside to inside, and finally is discharged back from the interior of the aircraft tail region into the aircraft environment via the first opening In contrast, in flying operation of the aircraft, the coolant flow may be controlled, e.g., by corresponding positioning of the cooler and the first opening, so that the coolant is supplied via the first opening into the interior of the aircraft tail region, and finally flows through the coolant channels of the cooler from inside to outside.
[0017] In the outer skin of the aircraft tail region, at least one second opening may be formed, and ambient air may be supplied through it to the driving device for driving the fan system for cooling. The second opening is preferably positioned so that ambient air which flows through the second opening into the interior of the aircraft tail region flows directly over the driving device for driving the fan system. Preferably, the second opening is arranged at a lesser distance from the transom of the aircraft tail region than the first opening
[0018] In the region of the first and/or second opening formed in the outer skin of the aircraft tail region, multiple lamellae, which essentially extend parallel to each other, may be provided. The lamellae may be adjustable in steps or continuously between a closed position in which they define a closed surface which cannot be flowed through and at least one open position in which they define a surface allowing to be flowed through via corresponding through-flow slits. By corresponding control of the position of the lamellae, the air volume flow which is fed via the first and/or second opening formed in the outer skin of the aircraft tail region into the interior of the aircraft tail region can be controlled flexibly as desired, depending on the cooling air requirement of the cooling system. Additionally, because of the flexible adjustability of the position of the lamellae depending on the cooling air requirement of the cooling system, optimization of the air resistance and consequently fuel consumption of the aircraft is made possible, since the ram effect of the lamellae in flying operation of the aircraft can always be chosen to be only as high as is necessary to achieve the desired air volume flow in the interior of the aircraft tail region.
[0019] The lamellae may be integrated into an outer skin contour of the aircraft tail region in the region of the first and/or second opening formed in the outer skin of the aircraft tail region, so that they seal or release the first and/or second opening directly, depending on their positions. However, alternatively the lamellae may be integrated into a flap, which itself is adjustable in steps or continuously between a closed position in which it seals the first and/or second opening formed in the outer skin of the aircraft tail region, and an open position in which it releases the first and/or second opening formed in the outer skin of the aircraft tail region. Such a configuration makes possible specially flexible control of the air volume flow which is supplied into the interior of the aircraft tail region, since on the one hand the flap itself, and on the other hand the lamellae, can be brought into corresponding positions to control the air volume flow. Integration of the lamellae into an outer skin contour of the aircraft tail region in the region of the first and second openings formed in the outer skin of the aircraft tail region is possible. Additionally, the lamellae, both in the region of the first and in the region of the second opening formed in the outer skin of the aircraft tail region, may be integrated into a flap. Finally, configurations in which the lamellae are integrated into an outer skin contour of the aircraft tail region in the region of one opening, and into a flap in the region of the other opening, are conceivable.
[0020] The lamellae are preferably adjustable into a first open position or a second open position, according to choice. In the first open position of the lamellae, an airflow which flows around the outer skin of the aircraft tail region in flying operation of the aircraft may flow onto an inner surface of the lamellae, which in the closed position of the lamellae faces an interior of the aircraft tail region. In this way, the lamellae can steer the air through the first and/or second opening into the interior of the aircraft tail region. In contrast, in the second open position of the lamellae, an airflow which flows around the outer skin of the aircraft tail region in flying operation of the aircraft may flow onto an outer surface of the lamellae, which in the closed position of the lamellae faces away from an interior of the aircraft tail region.
[0021] In their first open position, the lamellae generate a high ram pressure in the airflow which flows around the outer skin of the aircraft tail region in flying operation of the aircraft, and consequently make it possible to feed a large air volume flow into the interior of the aircraft tail region. However, this results in an increase of the air resistance and thus fuel consumption of the aircraft. In the second open position of the lamellae, the ram pressure which the lamellae generate in the airflow which flows around the outer skin of the aircraft tail region in flying operation of the aircraft, and consequently the air resistance which the lamellae generate, is significantly less. If only a little air is to be fed into the interior of the aircraft tail region, or if air is to be carried out of the interior of the aircraft tail region into the environment through the through-flow slits which the lamellae define, it is therefore useful to position the lamellae in their second open position, to avoid increasing the air resistance and therefore the fuel consumption of the aircraft unnecessarily.
[0022] The fan system of the aircraft tail region according to the invention may include two axial fans, which may be operated redundantly. However, preferably the fan system includes a radial fan. A “radial fan” here is understood to be a fan which sucks air in an axial direction, i.e., in a direction parallel to the axis of rotation of the fan, deflects it by 90° and finally carries it away in a radial direction. A radial fan makes it possible to implement large pressure increases, and in operation reacts insensitively to fluctuations in the flow of air fed to the fan. This makes specially efficient operation of the cooling system possible. At the same time, it may be possible to do without additional fans, and consequently operation of the cooling system with low noise may be achieved.
[0023] The first opening which is formed in the outer skin of the aircraft tail region is preferably positioned radially relative to the radial fan of the fan system. Through it, in operation of the radial fan, after flowing through the coolant channels of the cooler, cooling air can be fed specially efficiently out of the interior of the aircraft tail region back into the aircraft environment through the first opening, with low loss.
[0024] A driving device for driving the radial fan may extend from the radial fan in the direction of the transom of the aircraft tail region. The driving device may be in the form of an electric motor or similar, for example. A driving device which extends from the radial fan in the direction of the transom of the aircraft tail region is easily and conveniently accessible for maintenance and repair purposes. The driving device can also be replaced quickly if required.
[0025] A fuel tank of a fuel cell system may be positioned between the cooler and the fan system. The fuel tank may, for example, be adapted to receive hydrogen. In all operating phases of the cooling system, cooling air flows over a fuel tank which is positioned between the cooler and the fan system, and which consequently is always optimally ventilated. This increases the safety of the tank.
[0026] In a method according to the invention for operating a cooling system installed in an aircraft tail region as described above, with a cooler which forms a section of an outer skin of the aircraft tail region and includes coolant channels allowing a flow of ambient air therethrough, and extending from a first surface of the cooler to a second surface of the cooler, a fan system, and a first opening which is formed in the outer skin of the aircraft tail region, the fan system, at least in specified operating phases of the cooling system, conveys ambient air through the coolant channels of the cooler into an interior of the aircraft tail region. The ambient air which is supplied through the coolant channels of the cooler into the interior of the aircraft tail region in conveying operation of the fan system is discharged back into the aircraft environment through the first opening, which is formed in the outer skin of the aircraft tail region.
[0027] At least in specified operating phases of the cooling system, ambient air may be supplied through the first opening into the interior of the aircraft tail region, and discharged back through the coolant channels of the cooler into the aircraft environment, driven by differential pressure.
[0028] Ambient air may be fed through at least one second opening, which is formed in the outer skin of the aircraft tail region, to a driving device for driving the fan system for cooling.
[0029] In the region of the first and/or second opening formed in the outer skin of the aircraft tail region, multiple lamellae, which essentially extend parallel to each other, may be provided. The lamellae may be adjusted, depending on the operating state of the cooling system, in steps or continuously between a closed position in which they define a closed surface and at least one open position in which they define a surface allowing to be flowed through via corresponding through-flow slits.
[0030] The lamellae may be integrated into an outer skin contour of the aircraft tail region in the region of the first and/or second opening formed in the outer skin of the aircraft tail region. The lamellae may also be integrated into a flap, which itself is adjusted, depending on the operating state of the cooling system, in steps or continuously between an open position, in which it seals the first and/or second opening formed in the outer skin of the aircraft tail region, and an open position, in which it releases the first and/or second opening formed in the outer skin of the aircraft tail region.
[0031] The lamellae may be adjusted, depending on the operating state of the cooling system, into a first open position or a second open position, according to choice. In the first open position of the lamellae, an airflow which impinges around the outer skin of the aircraft tail region in flying operation of the aircraft impinges onto an inner surface of the lamellae, which in the closed position of the lamellae faces an interior of the aircraft tail region. In contrast, in the second open position of the lamellae, an airflow which flows around the outer skin of the aircraft tail region in flying operation of the aircraft impinges onto an outer surface of the lamellae, which in the closed position of the lamellae faces away from an interior of the aircraft tail region.
[0032] Ambient air which is supplied into the interior of the aircraft tail region may flow over a fuel tank of a fuel cell system, which is positioned between the cooler and the radial fan, for cooling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Preferred embodiments of the invention are now explained in more detail on the basis of the attached schematic drawings, of which
[0034] FIGS. 1 a to 1 d show a representation of a first embodiment of an aircraft tail region with a cooling system installed in the aircraft tail region,
[0035] FIG. 2 shows a detailed representation of a cooler of the cooling system,
[0036] FIG. 3 shows a three-dimensional exploded view of a radial fan of the cooling system,
[0037] FIGS. 4 a and 4 b show detailed representations of a first opening which is formed in an outer skin of the aircraft tail region, and which can be sealed by a conventional sealing flap,
[0038] FIGS. 5 a and 5 b show detailed representations of a first opening which is formed in an outer skin of the aircraft tail region, and in the region of which multiple lamellae are integrated into an outer skin contour of the aircraft tail region,
[0039] FIGS. 6 a and 6 b show a side view and plan view of a second embodiment of a aircraft tail region with a cooling system installed in the aircraft tail region, and
[0040] FIGS. 7 a and 7 b show a side view and rear view of a third embodiment of a aircraft tail region with a cooling system installed in the aircraft tail region.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] In FIGS. 1 a to 1 d, a first embodiment of an aircraft tail region 10 , in which a cooling system 12 is installed, is shown. A cooler 14 of the cooling system 12 forms a section of an outer skin 16 of the aircraft tail region 10 , said section being arranged at a first distance Al from a transom 15 of the aircraft tail region 10 . In particular, the distance Al of the cooler 14 from the transom 15 of the aircraft tail region 10 is chosen so that the cooler 14 is reliably outside a section of the aircraft tail region 10 which could be affected by a tail strike. The cooler 14 is arranged in a lower shell region of the aircraft tail region 10 , said lower shell region facing the ground in operation of the aircraft tail region 10 .
[0042] A main body of the cooler 14 comprises a material, e.g., a metal or a plastic material, in particular a fibre-reinforced plastic material, the mechanical properties of which are adapted to the requirements which are set for an aircraft outer skin section. This ensures that the cooler 14 meets the structural requirements which result from its positioning in the region of the aircraft outer skin. The cooler 14 is mounted detachably on corresponding supporting elements, e.g., components of the aircraft structure, and/or fixed to sections of the aircraft outer skin adjacent to the cooler 4 . Thus the cooler 14 can be detached from its position comparatively easily, and can make components which are arranged within the aircraft tail region 10 conveniently accessible for replacement or maintenance purposes.
[0043] As can be seen in the detailed representation of the cooler 14 in FIG. 2 , the main body of the cooler 14 has multiple lamellae 18 . The lamellae 18 delimit multiple coolant channels 20 , which extend from a first surface 22 of the cooler 14 to a second surface 24 of the cooler 14 . The first cooler surface 22 thus forms an outer surface of the aircraft outer skin, whereas the second cooler surface 24 forms an inner surface of the aircraft outer skin. Air can flow through the cooler 14 via coolant channels 20 which are formed in the cooler 14 . The air which flows though the coolant channels 20 is used to supply cooling energy to a fuel cell system on board the aircraft. For this purpose, the cooler 14 is in the form of a heat exchanger. When cooling air flows through the coolant channels 20 of the cooler 14 , the cooling energy content of the cooling air falls steadily by cooling energy transfer to the heat-generating component to be cooled. As explained in more detail below, cooling air can flow through the coolant channels 20 of the cooler 14 , as shown in FIG. 2 , from outside to inside, i.e., from the first cooler surface 22 in the direction of the second cooler surface 24 . However, the cooling air can also be guided through the cooler 14 from inside to outside, i.e., from the second cooling surface 24 in the direction of the first cooling surface 22 .
[0044] The first cooler surface 22 , which forms an outer surface of the aircraft outer skin, has a structure which is suitable for reducing the frictional resistance of the first cooler surface 22 in flying operation of an aircraft equipped with the aircraft tail region 10 , when air flows over the first cooler surface 22 . For example, the lamellae 18 which are formed in the main body of the cooler 14 in the region of the first cooler surface 22 can form fine, sharp-edged ribs, which are essentially aligned parallel to the airflow which flows over the first cooler surface 22 in flying operation of an aircraft equipped with the aircraft tail region 10 . Such a version of the first cooler surface 22 ensures that the frictional resistance of the aircraft is not increased by integration of the cooler 14 into the aircraft outer skin, but can even be reduced. This makes it possible to achieve fuel savings.
[0045] The cooler 14 also includes multiple ribs 26 , which extend from the first surface 22 of the cooler 14 . The ribs 26 function as flow baffles, and are aligned essentially parallel to flow lines of an airflow which flows around the first cooler surface 22 in flying operation of an aircraft equipped with the aircraft tail region 10 . The ribs 26 also have a contour which is curved in the direction of the first cooler surface 22 . A airflow which flows over the first cooler surface 22 in flying operation of the aircraft can be controlled as desired by the ribs 26 . The ribs 26 also protect the cooler 14 , and in particular the first cooler surface 22 , from external influences, e.g., bird strike, ice strike, etc.
[0046] The aircraft tail region 10 also includes a fan system 28 with a radial fan, which is arranged at a second distance A 2 from the transom 15 of the aircraft tail region 10 . The second distance A 2 is less than the first distance A 1 , i.e., the fan system 28 is arranged nearer the transom 15 of the aircraft tail region 10 than the cooler 14 . In operation, the radial fan which is shown in detail in FIG. 3 sucks air in the axial direction, i.e., in a direction parallel to the axis of rotation R of the fan, deflects the air by 90° and finally carries the air away in a radial direction. The radial fan is mounted by means of a holding frame 30 (see FIG. 3 ) in the aircraft tail region 10 . Alternatively, the holding frame 30 can also be a gasproof wall. A driving device 32 in the form of an electric motor, and controlled by a control unit (not shown), drives the fan system 28 . The driving device 32 for driving the fan system 28 extends from the radial fan in the direction of the transom 15 of the aircraft tail region 10 , and is therefore easily and conveniently accessible for maintenance and repair purposes. The driving device 32 can also be replaced quickly if required.
[0047] Finally, in the outer skin 16 of the aircraft tail region 10 , a first opening 34 is formed. The first opening 34 , which is formed in the outer skin 16 of the aircraft tail region 10 , is positioned radially relative to the radial fan, i.e., essentially at the same distance A 2 from the transom 15 of the aircraft tail region 10 as the radial fan. In flying operation of an aircraft equipped with the aircraft tail region 10 , a higher pressure acts on the section of the outer skin 16 in which the first opening 34 is formed than on the section of the outer skin 16 formed by the cooler 14 . In this way, in flying operation of the aircraft, ambient air can flow into the interior of the aircraft tail region 10 through the first opening 34 , and be fed back into the aircraft environment through the coolant channels 20 of the cooler 14 , driven by differential pressure. Operation of the fan system 28 is unnecessary for this purpose.
[0048] In ground operation of the aircraft, the driving device 32 , under the control of the control unit, drives the fan system 28 so that the radial fan sucks air out of the aircraft environment through the coolant channels 20 of the cooler 14 into the interior of the aircraft tail region 10 . Air is then carried out of the interior of the aircraft tail region 10 via the first opening 34 , which is positioned radially to the radial fan. Both in flying operation and in ground operation of an aircraft equipped with the aircraft tail region 10 , the air which is fed into the interior of the aircraft tail region 10 , when it flows through the interior of the aircraft tail region 10 , is fed via a fuel tank 36 of the fuel cell system to be cooled by means of the cooling system 12 . In this way, the tank 36 , which is suitable to receive hydrogen and arranged in the flow path of the cooling air between the cooler 14 and the fan system 28 , is always sufficiently ventilated.
[0049] In the outer skin 16 of the aircraft tail region 10 , a second opening 38 , through which ambient air can be fed to the driving device 32 for driving the fan system 28 for cooling, is also formed. The second opening 38 is positioned so that ambient air which is fed through the second opening 38 into the interior of the aircraft tail region 10 flows directly over the driving device 32 for driving the fan system 28 .
[0050] The first opening 34 which is formed in the outer skin 16 of the aircraft tail region 10 may be sealable by a conventional sealing flap 40 , shown in FIGS. 4 a and 4 b . Alternatively, however, the first opening 34 may also be sealable by multiple lamellae 42 which extend essentially parallel to each other and may be tilted relative to the outer skin 16 of the aircraft tail region 10 (see FIGS. 5 a and 5 b ). In the configuration shown in FIGS. 5 a and 5 b , the lamellae 42 in the region of the first opening 34 are integrated into an outer skin contour of the aircraft tail region 10 , and can be adjusted in steps or continuously between a closed position in which they define a closed surface and seal the first opening 34 , and two different open positions, in which they define a surface which can be flowed through via corresponding through-flow slits 43 .
[0051] In a first open position of the lamellae 42 (see FIG. 5 a ), an airflow L, which flows around the outer skin 16 of the aircraft tail region 10 in flying operation of the aircraft, flows onto an inner surface 42 a of the lamellae 42 , which in the closed position of the lamellae 42 faces an interior of the aircraft tail region 10 . The lamellae 42 thus deflect the air through the first opening 34 into the interior of the aircraft tail region 10 . In contrast, in a second open position of the lamellae 42 (see FIG. 5 b ), the airflow L, which flows around the outer skin 16 of the aircraft tail region 10 in flying operation of the aircraft, flows onto an outer surface 42 b of the lamellae 42 , which in the closed position of the lamellae 42 faces away from an interior of the aircraft tail region 10 .
[0052] In their first open position, the lamellae 42 generate a high ram pressure in the airflow L which flows around the outer skin 16 of the aircraft tail region 10 in flying operation of the aircraft, and consequently make it possible to feed a large air volume flow into the interior of the aircraft tail region 10 . The lamellae 42 can each have the same shape. In contrast, in the configuration according to FIGS. 5 a and 5 b , the extent, i.e., area, of the lamellae 42 increases in the direction of the airflow L. In this way, even lamellae 42 which in the first open position of the lamellae 42 according to FIG. 5 a are arranged “behind” other lamellae 42 in the direction of the airflow L still have an area onto which flow is possible, and can generate a ram pressure in the airflow L. On the other hand, if only a little air is to be fed into the interior of the aircraft tail region 10 , or if air is to be carried out of the interior of the aircraft tail region 10 into the environment through the through-flow slits 43 which the lamellae 42 define, it is therefore useful to position the lamellae 42 in their second open position, to avoid increasing the air resistance and therefore the fuel consumption of the aircraft unnecessarily.
[0053] The second opening 38 which is formed in the outer skin 16 of the aircraft tail region 10 can also be sealable by a conventional sealing flap. Alternatively, however, the second opening 38 can also be sealable by multiple lamellae 42 which extend essentially parallel to each other and can be tilted relative to the outer skin 16 of the aircraft tail region 10 .
[0054] A second embodiment of an aircraft tail region 10 , shown in FIGS. 6 a and 6 b , differs from the arrangement according to FIGS. 1 a to 1 d in that the fan system 28 , instead of a radial fan, has two or more axial fans which work redundantly. Also, the first opening 34 is positioned not in the region of a lower shell but in the region of an upper shell of the aircraft tail region 10 . In the region of the first opening 34 , a flap 44 , which can be adjusted between a closed position and an open position, is arranged. In its closed position, the flap 44 seals the first opening 34 . In contrast, in its open position, the flap 44 releases the first opening 34 . Lamellae 42 which can be tilted relative to a base area of the flap 44 are integrated into the flap 44 , and can be adjusted in steps or continuously between a closed position, in which they define a closed surface, and two different open positions, in which they define a surface which can be flowed through via corresponding through-flow slits 43 . Otherwise, the structure and mode of operation of the aircraft tail region 10 shown in FIGS. 6 a and 6 b correspond to the structure and mode of operation of the aircraft tail region 10 according to FIGS. 1 a to 1 d.
[0055] Finally, FIGS. 7 a and 7 b show a third embodiment of an aircraft tail region 10 , in which the two redundantly working axial fans are arranged in a flow path between the cooler 14 and the transom 15 of the aircraft tail region 10 , so that the first opening 34 is positioned in the region of the transom 15 . Otherwise, the structure and mode of operation of the aircraft tail region 10 shown in FIGS. 7 a and 7 b correspond to the structure and mode of operation of the aircraft tail region 10 according to FIGS. 6 a and 6 b.
[0056] As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.
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An aircraft tail region including a cooling system installed in the aircraft tail region. The cooling system comprises a cooler, which forms a section of an outer skin of the aircraft tail region, and includes coolant channels allowing a flow of ambient air therethrough, and extending from a first surface of the cooler to a second surface of the cooler. The cooling system also includes a fan system, which is adapted to convey ambient air through the coolant channels of the cooler at least in specified operating phases of the cooling system, and a first opening, which is formed in the outer skin of the aircraft tail region, and which allows, in conveying operation of the fan system, ambient air which is supplied through the coolant channels of the cooler into an interior of the aircraft tail region to be discharged back into the aircraft environment.
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[0001] This invention was made with government support under contract F33615-98-C-1212 awarded by Air Force Research Laboratory. The government has certain right in the invention.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention relates generally to methods and apparatus for the deposition or growth of thin films upon a substrate. More particularly, the invention pertains to method and apparatus for a liquid metal evaporation source for use in molecular beam epitaxy (MBE) and other epitaxy and deposition techniques predominantly used in semiconductor technology.
BACKGROUND OF THE INVENTION
[0003] The evaporation of metals in vacuum systems is widely used in industrial applications to form reflective and/or protective metal coatings. Evaporation of liquid metals such as Gallium (Ga), Indium (In), and Aluminum (Al) under ultra-high vacuum conditions in Molecular Beam Epitaxy (MBE) is also used in the growth of compound semiconductors such as Gallium Arsenide (GaAs) and Indium Phosphide (InP) and related materials. These thin semiconductor layers are used to fabricate a variety of technologically important electronic and optoelectronic devices such as microwave transistors, optical detectors and lasers.
[0004] These techniques are used in the manufacture of, among other things, compound semiconductors. Compound semiconductors are crystalline semiconductor materials made from a chemical compound using elements from groups III and V or groups IIB and VI of the periodic table, such that the compounds are isoelectronic with the elemental semiconductors (e.g., silicon and germanium from group IV). In addition, the resulting compounds have similar semi-conducting properties to silicon, though some important practical differences arise that enable use of these materials in the manufacture of special electronic devices and integrated circuits.
[0005] Compound semiconductors are generally characterized by a direct energy gap, which permits radiative transitions between conduction and valence bands to occur, resulting in the emission of electromagnetic radiation. The wavelength of the radiation is related to the energy band gap, and the compound semiconductors can be alloyed to produce the appropriate band gaps for emission of visible light, or infrared radiation for optical communications. These materials are therefore used for light emitting diodes (LEDs), semiconductor lasers, etc. GaAs and InP are also used in microwave devices and integrated circuits, including transferred electron devices, high electron mobility transistors (HEMT), and heterojunction bipolar transistors (HBT).
[0006] Epitaxy is a method of growing a thin layer of material upon a single-crystal substrate, such as silicon, so that the crystal structure of the layer is identical to that of the substrate. The material, which may be the same as the substrate or a different one, is usually deposited from a gaseous mixture (i.e., vapor phase epitaxy) but also may be deposited from a liquid mixture (i.e., liquid phase epitaxy). These techniques are extensively used in semiconductor technology when a layer (the epitaxial layer) of different conductivity or band gap than the substrate is required.
[0007] Vapor phase epitaxy (VPE), a form of chemical vapor deposition (CVD), is the most common method of epitaxy. For VPE, the material to be deposited on the substrate is heated to its gaseous state in a furnace also containing the substrate material. While the substrate material is held at a temperature just below its solidification point, the gas molecules reach the substrate and are deposited on its surface, thereby replicating the substrate crystal structure. The conditions in the furnace can typically be adjusted with respect to temperature and pressure to allow particular desired combinations of substrate and deposited material to be produced.
[0008] For example, the deposition rate is governed by the temperature of the sample and the pressure of the reactant gases inside the reactor. These parameters can also affect the quality of the resulting epitaxial layer, in terms of chemical purity and number of defects present in the crystalline film. In VPE, the reactants and conditions are chosen to enable the reaction at the semiconductor surface to produce a layer following the crystalline ordering of the underlying layer.
[0009] Often the reactants are inorganic materials, though recently the use of organic compounds containing metal atoms has been employed for VPE of compound semiconductors—otherwise known as organo-metallic vapor phase epitaxy (OMVPE). Generally, these reactions are carried out at reduced pressure, and the process is called low pressure chemical vapor deposition (LPCVD). Also, faster deposition occurs at higher pressures, and some processes can take place at atmospheric pressure; atmospheric pressure chemical vapor deposition (APCVD). Reaction rates can also be increased by using energetic reactant gases. For example, the use of a glow discharge or plasma at low pressure to provide highly energetic and reactive species is employed in plasma enhanced chemical vapor deposition (PECVD).
[0010] Similar to VPE, liquid phase epitaxy (LPE) is a method of growing an epitaxial layer on a substrate, but from a molten material. With LPE the substrate is placed in, for example, a slider while the material to be deposited is contained in molten form in, for example, a graphite “boat”. The molten material is supercooled to just below the solidification temperature, while the slider containing the substrate is moved slowly across its surface. Atoms of the molten material then solidify onto the substrate. This particular method of epitaxy is most useful for III-V or II-VI compound semiconductors, such as gallium arsenide substrates. LPE, however, has its limitations (e.g., LPE cannot produce very thin high-quality layers, etc.), but is inexpensive and capable of growing many material compositions. LPE is therefore still used in the manufacture of some devices, such as light-emitting diodes, that do not require such thin uniform high-quality layers.
[0011] Of particular use in semiconductor technology is the growth process of Molecular Beam Epitaxy (MBE). MBE is a growth process involving the deposition of thin films of material onto a heated substrate in a vacuum by directing molecular or atomic beams onto the substrate. Deposited atoms and molecules then migrate to their energetically preferred lattice positions on a heated substrate, thus, yielding film growth of high crystalline quality and optimum thickness uniformity. MBE is widely used in the research, development, and manufacture of compound semiconductors, as well as for thin-film deposition of elemental semiconductors, metals and insulating layers. Under suitable conditions the MBE process can be controlled to produce almost any required epitaxial layer composition, thickness and doping level with a resolution of virtually one atomic layer, to a high degree of accuracy and uniformity across a substrate wafer. Of course, MBE has its disadvantages, such as the high-vacuum requirements, complex and costly equipment, and the slow growth rate of the epitaxial layer.
[0012] A principal apparatus utilized in MBE deposition is the thermal effusion cell having a crucible, which contains the effusion material, for example gallium, arsenic, or other elements or compounds. During the MBE process, the crucible is heated to vaporize and effuse the material out of the crucible through an orifice into an ultra high vacuum growth chamber for deposition onto the heated substrate, which is located in the growth chamber. Typically, one or more cells are actuated in the growth chamber and generate a beam which is directed at a predetermined angle toward the substrate which is mounted on a rotating substrate holder. Control of the beam is typically accomplished via shutters and/or valves. During use, various preparatory procedures are first performed on the substrate. Then, the cells are powered up, heated and unshuttered. Finally, the desired epitaxial deposition is accomplished on the heated, rotating substrate. After growth is completed, the epitaxial wafer is cooled and removed from the chamber.
[0013] Conventional source crucibles are constructed of an inert refractory material, such as pyrolytic boron nitride (PBN), which is stable at high effusion temperatures. The crucibles are typically formed by a CVD process utilizing a forming graphite mandrel in a deposition chamber. In the past, various crucible designs and configurations have been used in the MBE process. However, these prior art crucibles have significant limitations. The primary problems associated with existing crucibles are (1) low capacity, (2) lack of uniformity, (3) oval defect production, (4) short term flux transients, (5) long term flux transients, etc.
[0014] The amount of material a crucible may hold for a particular MBE process is its capacity. Greater capacity permits construction of larger and/or a greater number of devices per load of source material in the crucible. The desired capacity has been achieved in some designs by utilizing a straight-wall, cylindrical configuration. However, crucibles having a cylindrical configuration throughout tend to provide poor depositional uniformity because the molecular beam emitted from the zero draft cylindrical orifice is too tightly focused or collimated upon the substrate holder.
[0015] Next, uniformity relates primarily to the uniformity of the thickness of the layers deposited over the target substrate area via the material emitted from the orifice of the crucible but may also be compositional in nature. Uniformity has been achieved in some conventional designs by utilizing a conically configured crucible body having a positive draft. However, crucibles having a conical configuration have limited capacity, exhibit depletion effects, and are prone to flux transients (the volume of a cone is only ⅓ the volume of a cylinder with the same height and base area).
[0016] Morphological defects present on the formed semiconductor device are called oval defects. Source-related oval defects are thought to be caused by “spitting” from the material melt at the crucible base which occurs when droplets of condensed material form at the crucible orifice (due to a reduced temperature in the orifice region) and then roll back into the melt. Oval defect production has been reduced in some designs by heating the orifice or lip of the crucible to prevent the material condensation, commonly referred to as “hot lip” devices. A disadvantage with some hot lip source designs is that they produce a hydrodynamically unstable flux, they tend to produce undesirable levels of impurities due to enhanced outgassing, and they often exhibit rapid depletion effects.
[0017] Lastly, short term or shutter-related flux transients are changes in the effusion rate over time due to the activation of the source shutter, which causes radiational cooling of the crucible while long term flux transients are changes in effusion rate over time due to decreases in the surface area of the melt. Generally, flux transients are a problem in crucible designs having a conical configuration throughout.
[0018] Numerous known crucibles are well suited for use in an MBE effusion cell. For example, a typical MBE effusion cell, generally would comprise a head assembly and a mounting flange and support assembly. The mounting flange and support assembly couples the effusion cell to an MBE growth chamber and supports the head assembly at a predetermined position within the growth chamber. The crucible is preferably constructed of PBN and has a conical configuration with an outwardly oriented orifice having an annular lip. The effusion cell may include various optional features such as an integral shutter, an integral water cooling system, and the like.
[0019] Another type of apparatus utilized in MBE processes is the gas plasma source or emitter. Gas plasma sources have a plasma chamber with a gas inlet attached at one end for input of a gas such as Nitrogen into the chamber. A high frequency RF coil or plate is then used to crack the gas and form an active species, for example, atomic Nitrogen, which is effused through an output end, typically disposed opposite the gas inlet end. The output end of the emitter typically has one or more apertures. The effused species egresses through the output end apertures into an ultra-high vacuum growth chamber where the species combines with other elements or compounds. An example of this process is a Nitrogen gas plasma source used to generate non-ionized N 1 to subsequently yield Gallium Nitride in the growth chamber.
[0020] Prior art plasma chambers are typically multi-piece structures. The various components of the structure are typically constructed of pyrolytic boron nitride (PBN). These multi-piece chamber structures have significant limitations. A primary problem is that they are prone to leaking when under gas pressure during operation. Leaking gas will not be cracked by the source and this results in a loss of efficiency. Other problems found in prior art sources include generation of instabilities, high levels of N 2 gas in the growth environment, and low levels of N 1 .
[0021] One solution to these problems has been to use quartz to form the chamber because quartz can be shaped into a one piece design. However, for some high temperature applications, such as growth of Gallium Nitride crystals, the quartz tube can melt and lose its shape. Also, quartz can contribute undesirable Oxygen (O) and Silicon (Si) gas into the growth environment
[0022] With MBE, elemental arsenic and phosphorous are often heated to obtain the species necessary to grow the desired semiconductor layers. However, the species of arsenic, i.e., As 4 , derived from heating elemental arsenic or phosphorous are difficult to handle and the tetramer form leads to point defects or regions of high phosphorous or arsenic concentrations in the growing layer. To avoid these problems, phosphine, PH 3 , and arsine, AsH 3 , have been used in CVD and MBE growth processes. These materials are generally broken down into smaller molecules or components by heating the molecule above its bond breaking temperature, i.e., “cracked” into useful species of P 2 and As 2 by passing them through a heated zone to liberate the hydrogen as H 2 gas. The process of using the gas in a heated atmosphere to break down the arsine and phosphine is generally referred to as thermal cracking. Thermal cracking aims at the reduction of molecular size by application of heat without any additional sophistication such as catalyst or hydrogen.
[0023] Thermal cracking is achieved in MBE processes through the use of a thermal cracker. A thermal cracker is typically used for materials, like arsenic, where it is desirable after evaporation of the source material to further crack the molecules of the source material. Cracking effusion devices first sublimate solid source material and then “crack” it, that is, convert the vaporous material to smaller atomic species by subjecting it to extremely high temperatures. A thermal cracker typically has two or more thermal zones. The crucible of a two zone cracker generally has a large body portion located in the first, lower temperature zone and a smaller diameter cracking portion extending through the second, higher temperature zone. The source material is placed in the body portion, where it is heated, causing the material to evaporate and effuse into the cracking portion. The higher temperature in the second zone (or cracking portion) causes the source material to crack as it passes therethrough. The cracked material then effuses out of the exit orifice, where it is deposited onto the substrate.
[0024] Because of the inwardly directed transition area between the body portion and the cracking portion of the crucible used in such thermal crackers, it was not possible to make such crucibles for crackers out of PBN. Instead, these crucibles are typically made out of a weldable metal such as tantalum or titanium. This severely limited the types of source materials which could be used in a thermal cracker, because the tantalum or titanium crucible is not suitable for use with liquid metal source materials, such as Silver (Ag), Aluminum (Al), Gold (Au), Boron (B), Barium (Ba), Bismuth (Bi), Cadmium (Cd), Cobolt (Co), Cesium (Cs), Copper (Cu), Iron (Fe), Gallium (Ga), Gadolinium (Gd), Germanium (Ge), Mercury (Hg), Indium (In), Potassium (K), Lanthanum (La), Lithium (Li), Sodium (Na), Nickel (Ni), Lead (Pb), Palladium (Pd), Praseodymium (Pr), Platinum (Pt), Rubidium (Rb), Antimony (Sb), Scandium (Sc), Selenium (Se), Silicon (Si), Tin (Sn), Tellurium (Te), Thallium (Tl), Vanadium (V), Ytterbium (Y), and Zinc (Zn).
[0025] In MBE, molecular beams of certain elements, such as pure phosphorus, are directed onto the surface of a substrate, where they react with each other to create a layer with the desired properties used to construct complex semi-conducting structures. Phosphorus effusion devices are constructed using either a one or two chamber design. In a single chamber design, solid red phosphorus is sublimated at about 300 Celsius (C) in a furnace or crucible, which is vacuum evacuated. When the red phosphorus is sublimated, it produces both red phosphorus vapor and white phosphorus vapor, which is then introduced to the phosphorus cracker by a valve before being directed to the substrate.
[0026] Such a single chamber design suffers from at least one drawback. In particular, some of the vaporous white phosphorus condenses on the walls of the chamber. At an operating temperature of 300 C, the vapor pressure of white phosphorus is significantly higher than that of red phosphorus. As a result, when the valve is closed, a large pressure build-up occurs in the chamber. When the valve is then opened to the cracker, pressure bursts occur into the MBE chamber. The excess release of phosphorus into the MBE chamber is harmful to the MBE growth system. In addition, the MBE chamber requires several hours after such a pressure burst to recover to a proper working pressure.
[0027] To reduce this problem, it has been proposed to add a second chamber to the system design. The vaporous white phosphorus is purposefully condensed in a second chamber so that it deposits on the walls of the second chamber. This second chamber is independently temperature regulated so that the walls are cooler to encourage the white phosphorus condensation, which significantly reduces the vapor pressure within the second chamber. A valve admits the vaporous phosphorus to the cracker where P 4 phosphorus is converted to P 2 phosphorus.
[0028] A critical requirement in MBE growth is the need to precisely control the metal evaporation rates to reproducibly grow thin semiconductor layers with precise thickness and compositions. In addition, the metal evaporation rates must be controlled to within 0.5 percent in order to obtain lattice-matching of ternary and quaternary alloys on host substrates (for example In 0.532 Ga 0.478 As and In 0.521 Al 0.479 As on InP substrates). In conventional MBE systems, metals are usually evaporated in heated crucibles that are conical in shape to achieve thickness and compositional uniformity in the deposited films over large rotating substrates or multiple substrate holding platens. (See for example, Parker, Herman, etc. regarding MBE technology). The molecular beam fluxes emanating from the crucible and incident upon the substrate can be approximated by the Knudsen effusion equation that is given by:
J ( T ) = AP ( T ) Cos Φ pd 2 ( MT ) 1 / 2 Equation ( 1 )
where J(T) is the molecular flux density incident upon the substrate in units of cm −2 s −1 , T is the absolute temperature in Kelvin (K), A is the area of the liquid metal surface in cm 2 , P(T) is the metal vapor pressure of the element in Torr, d is the distance between the metal surface and the substrate in cm, M is the molecular weight of the metal in gram-mole −1 , and Φ is the angle between the normal to the substrate surface and the metal crucible axis.
[0029] The geometry of a prior art conical crucible evaporation source is shown in FIG. 1 . A conical crucible 10 preferably made from Pyrolytic Boron Nitride (PBN) or Pyrolytic Graphite (PG) is radiantly heated by a resistive heater element 18 . The crucible temperature is sensed and controlled by a thermocouple 17 to establish a desired evaporation rate of the metal atoms upon the substrate. It is seen that the taper angle of the conical crucible 104 enables the substrate holder 11 heated by a resistive heating element 16 to be exposed to the entire evaporation surface of the metal to provide uniform coating of the metal film through rotation of the substrate 19 . The conical crucible taper angle 104 prevents shadowing of the substrate by the crucible walls as the liquid metal is depleted in the crucible over time through evaporation of the metal. The initial surface area of the metal 12 is reduced over time due to metal depletion to a final surface area 13 . The distance of the metal surface to the substrate also increases from an initial distance 15 to a final distance 14 .
[0030] The depletion effect of the metal in the conical crucible leads to a decrease in the metal evaporation rate impinging upon the substrate (at a fixed crucible temperature) over time due to two geometrical effects. The first geometrical effect is that the evaporation surface area A is decreased due to metal depletion leading to a reduction in evaporation rate at a fixed evaporation temperature as given in Equation 1. The reduction in the surface area of the metal from an initial area 20 at initial time to t 0 a reduced area 21 at a later time t 1 is illustrated in FIG. 2 . The shape of the metal surface area is elliptical since the crucible is normally tilted at an angle to the substrate surface normal as shown in FIG. 1 . The second geometrical effect is that the distance d between the metal evaporation source and the substrate also increases due to depletion of the metal source which again leads to a reduction of evaporation rate at a fixed evaporation temperature as given in Equation 1. The principle of the second geometrical effect has been reported in Jones et al. “Linear Motion Oven for Variable Incident Group III Flux” J.Vac.Sci.Technol. B 13(2) March/April 1995, which discloses an MBE effusion cell with an adjustable source-to-substrate distance to mechanically adjust the evaporation rate. Although this method may be useful in some circumstances, there is a limited practical range over which this distance can be adjusted.
[0031] In order to maintain a constant metal evaporation rate upon the substrate, the crucible temperature must be gradually increased with time to compensate for the reduction in metal surface area A and increased source-to-substrate distance d. As given in Equation 1, the increase in cell temperature leads to an increase in the vapor pressure of the metal P(T) to offset the decrease of A and the increase in d. This requires a time-consuming and tedious re-calibration procedure that is normally performed daily in the MBE growth process. Errors in flux measurement can result in layer thickness and compositions that do not meet specifications that adversely affect wafer yields. In addition, the metal fluxes cannot be measured in real-time during the MBE growth process leading to further errors and decreased wafer yields. Lattice-matching of semiconductor layers becomes problematic near the end of the life of the source charges as the metal surface areas reach a minimum area resulting in rapid changes in metal evaporation rates with time.
[0032] Several metal evaporator designs have been used to overcome the problem of the reduction in surface area in conical crucible evaporation sources due to metal depletion. One such example, shown in FIG. 3 , exhibits low flux transient behavior as shutters of individual furnaces are opened to initiate the process and with excellent flux uniformity over the surface being processed and over the processing time. Here, the crucible is designed for liquid melts of Group III metals, including Gallium, Indium, and Aluminum, and comprises a two member construction in which the outer member (i.e., containing the melt) is generally cylindrical and of maximum capacity consistent with the furnace interior, and the inner member has a conical configuration with a small aperture at the bottom for optimum molecular beam formation. The conical member increases the thermal impedance between the melt surface and the interior of the MBE system to reduce the flux transient and increases the uniformity of the molecular beam over the area being processed, and over the time that the process is being conducted.
[0033] FIG. 3 shows a prior art design making use of a truncated conical crucible insert 31 with open top and bottom circular orifices inserted in a cylindrical crucible 30 which holds the liquid metal source 36 . A radiant resistive heater element 34 is located in close proximity to the mouth of the cylindrical crucible and the truncated conical insert. The temperature of the cylindrical crucible is sensed and controlled by a thermocouple 35 . The advantage of this cell configuration is that the surface area of the metal does not change from its initial surface area 32 to intermediate surface area 33 measured at a later time. Only when the edge of the metal surface touches the bottom edge of the cylindrical crucible will the surface area of the metal 37 decrease. This configuration significantly lessens the reduction in the evaporation rate as the metal is depleted in the crucible since the surface area of the metal stays approximately the same for a long period of time during metal evaporation. However this metal evaporator still has several problems. Since the source-to-substrate distance still increases with time, this will result in a reduction in metal evaporation rate. Therefore the crucible temperature still must be gradually increased with time in order to maintain a constant metal evaporation rate. Also this configuration leads to some focusing of the metal beam flux over the substrate as the metal surface recedes in the cylindrical crucible which adversely affects the deposition uniformity across the substrate. Another problem with this cell configuration is that the truncated conical crucible 31 is indirectly heated by the radiant heater element 34 through the walls of the cylindrical crucible 30 . This leads to condensation of metal droplets on the conical crucible that fall back by gravity into the metal evaporator which leads to numerous “spitting” defects in the grown layers. This problem has been solved in another design that uses a self-heated truncated conical insert placed in a similar cell configuration. The source includes an open-ended crucible and a removable orificed covered plate for covering the open end of the crucible, with the cover plate having an encapsulated heater to reduce orifice blockage. The self-heated conical insert can be maintained at a higher temperature than the metal surface to eliminate any condensation of metal droplets on the insert.
[0034] Another evaporator configuration that behaves similarly to the previously described evaporator is illustrated in FIG. 4 . In this design a single-piece crucible 40 is formed by chemical vapor deposition of pyrolytic Boron Nitride (PBN) on a shaped graphite mandrel. Through high temperature oxidation, the graphite mandrel is burned away leaving a cylindrically shaped PBN bottom reservoir 45 that contains the liquid metal source. A conical shaped nosecone 41 formed on top of this reservoir is used to broadly diffuse the metal beam flux to improve the uniformity of the deposited metal films. This evaporator design has several advantages over the previous designs. The single-piece crucible design eliminates any possibility of metal flux leakage since there are no mating surfaces between the reservoir and the nosecone. Also the nosecone can be heated to very high temperatures by the radiant heater element 44 to prevent condensation of metal droplets that can cause “spitting” defects. Additionally, the initial surface area remains constant throughout most of the lifetime of the metal source 46 until the edge of the metal surface 47 touches the crucible bottom 411 . Since the source-to-substrate distance still increases with time, the cell temperature controlled by the thermocouple must still be gradually increased in order to maintain a constant metal evaporation rate. The deposited metal uniformity across the substrate will also degrade with time due to the focusing affect of the nosecone as the metal surface recedes in the cylindrical crucible due to metal depletion from evaporation. Another problem of the single piece crucible design is that the narrow opening of the nosecone attached to the reservoir requires loading of small solid pellets of the metal source material thus reducing the loading volume of the source material by approximately 50%.
[0035] The crucible 40 generally comprises a base section 45 and a conical section with a first or outer orifice 49 disposed at one end of the conical section and open to the exterior of the crucible 40 . The base section 45 and a conical section form a single, unitary piece. The crucible 40 is formed of an inert, corrosion resistant material. A preferred material is PBN, such as PyroSyl™ sold by CVD Products, Inc. of Hudson, N.H. The crucible 40 is constructed via a chemical vapor deposition process set forth in detail below. All boundary edges between the base member 45 and conical member elements mentioned below in detail are preferably radius edges. In the embodiment of crucible 40 shown, the length and other dimensions of may be varied consistent with the basic teachings of this invention.
[0036] The base section 45 has a substantially cylindrical configuration with a side wall 416 , a bottom 411 disposed at one end of the side wall, and a negative draft tapered wall or neck (formed in conjunction with nosecone 41 ) disposed at the opposite end of the side wall. The side wall 416 has a predetermined substantially uniform circumference and a predetermined length. The negative draft wall tapers inwardly (laterally) towards the central longitudinal axis (not shown) of the crucible 40 (and hence, the side wall 416 ) preferably at an angle approximately 45.0 degrees with respect to the longitudinal plane of the exterior of the base section 45 . The negative draft wall terminates at its outward end to define a second or inner orifice 413 . The second orifice 413 is a region of smallest diameter in the crucible 40 .
[0037] The conical section is defined by the portion of the crucible extending from the second orifice 413 to the periphery of the first orifice 49 . The conical section comprises a positive draft wall 414 and an annular lip 415 . The wall 414 tapers outwardly (laterally) away from the central longitudinal axis of the crucible 40 at a preferred approximate angle of 9.0 degrees measured with respect to the central axis. The annular lip 415 extends outwardly from the terminal edge of the wall 414 .
[0038] The crucible 40 is typically oriented upwardly at an angle for MBE. An element or compound is added to the crucible and heated by the dual filament system, for example, of an effusion source to form a melt. In use, the conical section of the crucible 40 yields a level of thickness uniformity which matches that provided by conical crucibles. Additionally though, the design minimizes depletion effects. In all types of cells the beam equivalent pressure at a constant cell temperature decreases over time due to depletion of the source melt material. This effect is greater in cells using conical crucibles because of more rapid reductions in melt surface area in those cells. The effect is further increased in hot lip cells because they are typically somewhat less efficient in their use of material. Presumably, this is due to reevaporation from the hot lip area, such reevaporation not being directed toward the substrate. The crucible 40 of this invention virtually eliminates depletion effect by providing a melt surface 42 which is consistent in size (area) and shape at different levels 43 . The portion of the melt surface “seen” by the substrate is equivalent to the size of the inner orifice 413 . In contrast, in crucibles which are conical throughout, the distance between the crucible orifice and the melt surface increases and the melt surface area decreases as the melt charge depletes in volume, thus causing them to exhibit enhanced depletion effects. Another advantage of the crucible 40 of this invention is the large crucible volume provided by the straight wall, cylindrical base section 45 , which increases useful capacity in comparison to conical crucibles. A further advantage is that the inner orifice 413 provided by the integral conical section forms a thermal baffle between melt and the shutter (not shown) improving hydrodynamic stability and reducing shutter-related transients. Finally, the integrally formed conical section enables optimal positioning of the tip filament of the dual filament heating system to minimize oval defect production.
[0039] In another example, a phosphorus effusion source describes a sublimating and cracking apparatus for producing a beam of molecules to be deposited on a substrate. This example is particularly useful with phosphorus as the source material includes a vacuum jacket enclosing and supporting a red phosphorus crucible, a condensing crucible for white phosphorus and a connecting tube within a vacuum space. Red phosphorus is first transformed and deposited as white phosphorus in the condensing chamber, which is then directed to a cracking section where the white phosphorus is cracked and subsequently directed to the substrate.
[0040] Another example is an apparatus for varying the flux of a molecular beam emanating from an effusion source. The apparatus includes a means for controllably adjusting the angular distribution of a molecular field effusing from a source material within the effusion cell, thereby adjusting the flux of the beam. Also disclosed is a method which includes the step of selectively altering the angular distribution of an effusing molecular field produced by a heated source material, which comprises the molecular beam, thereby varying the flux of the beam.
[0041] Yet another example of an effusion source for the generation of molecular beams is adapted to be positioned at an angle to the horizontal within a vacuum chamber of an MBE system including heating structures around the source to create uniform temperatures across the source in planes substantially parallel to the horizontal. This causes uniform temperatures in planes substantially parallel to the horizontal in materials placed within the source and intended for MBE applications.
[0042] Another example comprises a vaporization chamber containing the material to be vaporized and provided with at least one opening with a given cross-section for maintaining the material to be vaporized in the liquid state within said chamber and for emitting controlled flow molecular beams. It further comprises a sleeve integral with the vaporization chamber surrounding the opening or openings having a given cross-section, and heating means for maintaining the temperature within the vaporization chamber and for obtaining an adequate temperature in the sleeve to prevent condensation of the vaporized material in said sleeve and in the opening or openings having a given cross-section.
[0043] Another example of an evaporation source incorporates a shaped nozzle. The evaporation source is such that an evaporation material is vaporized and jetted through a nozzle having a gradually opening cross-section, whereby the size of atom clusters of the jetted vapor can be controlled.
[0044] Another apparatus is a rapid response evaporator for material deposition in vapor and comprises a vessel which is heated to a temperature just above the melting temperature of the liquid which it contains. A funnel shaped evaporator structure is inserted into the heated liquid in which the vertical tube is a capillary structure to raise the heated liquid from the vessel. Because of the low thermal mass of the upper portion of the evaporator and the liquid in its capillary structure, it can respond to heat changes quickly enough to rapidly vary the rate of evaporation and the thickness of the deposited coating.
[0045] There are numerous problems and disadvantages associated with the prior art liquid metal evaporation sources discussed above. For example, these prior art embodiments suffer from inconsistent evaporation and deposition rates, melt depletion, exhibit a need for frequent recalibration to accompany associated changes in MBE process rates, and small, low capacity crucibles that result in a low overall throughput of substrate deposition.
SUMMARY OF THE INVENTION
[0046] The present invention provides a new liquid metal evaporation source configuration, which overcomes the disadvantages and limitations of the prior art sources. More particularly, disclosed is a new liquid metal evaporation source for use in MBE and other related metal vacuum deposition techniques, which consists, in the preferred embodiment, of three separately heated temperature zones. The first zone is the evaporator, including an integral level sensor used to measure and regulate metal height, maintained at a high temperature to evaporate a liquid metal contained in a crucible. The second zone operates as a reservoir for the liquid metal source in the shape of a hollow cylinder with a close fitting circular piston, held at a temperature substantially below that of the evaporator but above the melting point of the metal. The third zone consists of a hollow transport tube that connects the evaporator and reservoir, sustained at an intermediate temperature between their temperature zones. When pressure is applied to the reservoir piston, liquid metal is forced through the tube into the evaporator.
[0047] Melt depletion due to metal evaporation and the consequent reduction in the metal deposition rate is a problem that is overcome by the subject invention. This is accomplished through the use of a separate high capacity reservoir to contain the liquid metal that is attached to the metal evaporator by means of a co-joining hollow transport tube. The reservoir is used to replenish the metal lost during the evaporation process. The reservoir is most conveniently formed in the shapes of a hollow cylinder with a close-mating circular piston made from refractory material, preferably high purity, densified graphite and/or pyrolytic boron nitride. The cylinder and piston can be machined to close tolerances to prevent leakage of the liquid metal out of the containing wall of the reservoir. The surface tension of the liquid metal prevents it from penetrating through the narrow gap between the reservoir cylinder and the circular piston walls. Linear motion of the piston in the cylinder is used to force the liquid metal through the hollow transport tube into the high temperature evaporator. The evaporator, hollow transport tube, and reservoir are all independently heated to prevent solidification of the liquid metal.
[0048] The height of the liquid metal in the evaporator can be easily sensed through the use of one or two conducting probes insulated from the evaporator crucible and are preferably made from graphite or other refractory materials that do not react with the heated liquid metal. A low resistance contact is formed when the liquid metal just comes in contact with the conducting probes similar to a liquid mercury switch that is normally used in thermostats to control ambient temperature. The low resistance contact between the metal and the conducting probes can be input into a feedback control circuit that can adjust the linear position of the piston in the reservoir by means of a motor-driven linear feedthrough attached to the piston. In this manner, a constant liquid metal height in the evaporator can be maintained to produce a constant evaporation rate on the substrate throughout the lifetime of the liquid metal source charge. In one embodiment of this invention, the evaporator, hollow transport tube, and reservoir cylinder are machined concentrically from a single piece of refractory material, preferably high purity, densified graphite on which may be applied a thin coating of pyrolytic graphite (PG) and/or pyrolytic boron nitride (PBN). This single-piece construction eliminates any possibility of liquid metal leakage between the evaporator, hollow transport tube, and the liquid metal reservoir.
[0049] In a second embodiment of this invention, both the concentric evaporator and the hollow transport tube are joined to the liquid metal reservoir by machined mating flanges. One version of this design joins the axes of the hollow transport tube and the reservoir at a right angle. This configuration allows the liquid metal reservoir to be located outside of the cell port on the MBE system or vacuum chamber. This enables a very large capacity reservoir to be constructed that provides very long operating times before the reservoir needs to be reloaded. This configuration also reduces the hydrostatic pressure on the piston in the reservoir from the total height of the liquid metal above the reservoir. The non-concentric configuration reduces the possibility of liquid metal leakage around the cylinder walls and piston by reducing the hydrostatic pressure of the liquid metal on the piston. This also enables much larger capacity reservoirs to be constructed that are external to the MBE vacuum chamber, which results in higher throughput of deposited substrates.
[0050] Consequently, it is an object of the invention to provide a new liquid metal evaporation source which comprises three separately heated temperature zones to minimize the melt depletion of the liquid metal and consequently minimize reduction in the deposition rates.
[0051] It is another object of this invention to provide a liquid metal evaporation source with an integral level sensor and an external reservoir for liquid metal to replenish the evaporator which results in a time invariant constant melt surface area and metal source-to-substrate distance. The two insulated conductor probes within the evaporator crucible comprise a sensor used to regulate the height of liquid metal. Feedback input from the sensor allows for active position adjustment of the reservoir piston. This level sensor feedback control enables a constant level height of the liquid metal in the evaporation source. This combination of height detection sensing and corresponding piston adaptation results in metal deposition rates which are time invariant.
[0052] A further object of this invention is to provide a constant evaporation rate and high uniformity of metal deposition on a rotating substrate or multiple substrate containing platen that is maintained throughout the entire capacity and operating time of the liquid metal reservoir source. The existence of a separate reservoir allows for the constant replenishment of metal lost during the evaporation process. A uniform evaporator liquid metal height is successfully maintained by the evaporator sensor/reservoir piston combination. As a result, a consistent evaporation area is preserved and a constant metal evaporation rate retained.
[0053] Yet another object of this invention is the elimination of the time-consuming process for re-calibration of the metal evaporation rates normally required in prior art conical crucible metal evaporation sources due to metal source depletion effects. As previously explained, a uniform evaporation area and rate is sustained within the evaporator through the implementation of a liquid metal height sensor that serves to adjust the reservoir piston's position. The provision for a separate reservoir connected to the evaporator by a hollow transport tube allows for large capacity reservoir construction. The metal source therefore is depleted at a much slower rate and re-calibration is not frequently required.
[0054] Still another object of this invention is to provide higher throughput of deposited substrates in an MBE system. A non-concentric system configuration allows reservoir location outside of the vacuum chamber of the MBE system. This provides an opportunity for a large capacity reservoir to be utilized, allowing for longer operation periods and a resulting increased throughput.
[0055] Other objects, features, and characteristics of the present invention, as well as the methods of operation and functions of the related elements of the structure, and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following detailed description with reference to the accompanying drawings, all of which form a part of this specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] A further understanding of the present invention can be obtained by reference to a preferred embodiment set forth in the illustrations of the accompanying drawings. Although the illustrated embodiment is merely exemplary of systems for carrying out the present invention, both the organization and method of operation of the invention, in general, together with further objectives and advantages thereof, may be more easily understood by reference to the drawings and the following description. The drawings are not intended to limit the scope of this invention, which is set forth with particularity in the claims as appended or as subsequently amended, but merely to clarify and exemplify the invention.
[0057] For a more complete understanding of the present invention, reference is now made to the following drawings in which:
[0058] FIG. 1 shows a cross-sectional view of a prior art conical crucible, liquid metal evaporator, and heated substrate in an MBE system;
[0059] FIG. 2 illustrates the change in liquid metal surface area with time due to metal depletion from evaporation in a prior art inclined conical crucible, such as that shown in FIG. 1 ;
[0060] FIG. 3 shows a cross-sectional view of a prior art truncated crucible insert in a cylindrical crucible containing a liquid metal;
[0061] FIG. 4 shows a front view of a prior art unibody, monolithic negative draft MBE crucible;
[0062] FIG. 5 shows a cross-sectional view of one embodiment of a liquid metal evaporation source according to the present invention illustrating a single-piece concentric evaporator crucible, hollow transport tube and liquid metal reservoir wherein the liquid metal reservoir consists of a hollow cylinder and mating piston machined from a single piece of refractory material together with an integral liquid metal level sensor;
[0063] FIG. 6 shows a cross-sectional view of a preferred embodiment of a liquid metal evaporation source according to the present invention illustrating a concentric evaporator and hollow transport tube joined by leak-proof mating flanges at a right angle to an external cylindrical reservoir and mating piston;
[0064] FIGS. 7A & 7B show a schematic diagram of the preferred embodiment of an integral liquid metal level sensor according to the present invention comprising a PBN coated graphite nosecone with an extended sensor probe that is insulated from the graphite crucible wall and is inserted in the top opening of the evaporator crucible; and
[0065] FIG. 8 shows a schematic diagram of the preferred embodiment of an automated feedback sensor control circuit according to the present invention to control the linear position of the piston within the evaporator to maintain a constant liquid metal level.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0066] As required, a detailed illustrative embodiment of the present invention is disclosed herein. However, techniques, systems and operating structures in accordance with the present invention may be embodied in a wide variety of forms and modes, some of which may be quite different from those in the disclosed embodiment. Consequently, the specific structural and functional details disclosed herein are merely representative, yet in that regard, they are deemed to afford the best embodiment for purposes of disclosure and to provide a basis for the claims herein which define the scope of the present invention. It should be noted that those individuals skilled in the art may be able to make some modifications of the preferred embodiments but which are based upon the underlying teachings contained within the subject invention.
[0067] Referring first to FIG. 5 , illustrated is one embodiment of a liquid metal evaporation source 500 according to the subject invention. Specifically, liquid metal evaporator 56 , hollow transport tube 54 , and hollow reservoir cylinder 50 are all machined from a single piece of refractory material, preferably high-purity densified graphite that is optionally coated with a thin layer of chemical vapor deposited pyrolytic graphite (PG) or pyrolytic boron nitride (PBN). Likewise, a close-mating piston cylinder 51 is machined from the same or similar refractory material to make a leak-tight seal for the liquid metal 503 held in the reservoir cylinder 50 . The evaporator wall 522 , the hollow transport tube wall 542 , and the hollow reservoir wall 502 which contain the liquid metal 503 are preferably machined in cylindrical form to minimize the gaps between the reservoir piston 51 and optional nosecone and level sensor 521 . The liquid metal will be contained within the reservoir cylinder by the surface tension of the liquid metal under certain conditions wherein the gap separating the walls of the reservoir cylinder 502 and the piston 51 are machined to be within required tolerances. A mathematical expression for the maximum permissible gap spacing between the cylindrical walls of the reservoir and piston is derived in subsequent paragraphs.
[0068] Evaporator heater element 57 , hollow transport tube heater element 55 , and reservoir heater element 53 are used to respectively heat by infrared radiation the walls of the evaporator 56 , hollow transport tube 54 , and reservoir 50 to prevent solidification of the liquid metal in any part of cell 500 . Graphite has efficient black-body radiation absorption that will reduce the required heater element powers to achieve nominal operating temperatures for the cell in comparison to other refractory materials such as pyrolytic boron nitride (PBN) or SiO 2 (quartz). Evaporator thermocouple 511 , hollow transport tube thermocouple 512 , and reservoir thermocouple 513 are used to independently sense and control the respective temperatures in the three separate temperature zones. Also optional radiation shields typically made from Tantalum (Ta) foil (not shown) and optional water-cooling jacket (not shown) to surround the heater elements and provide thermal isolation of the respective temperature zones may be used in accordance with the invention. Under normal operation, evaporator 56 is preferably held at the highest temperature to vaporize the liquid metal, while hollow transport tube 54 is held at some intermediate temperature and reservoir 50 is held at the lowest temperature, preferably just slightly above the melting point of the metal material being used for deposition. Of course, other temperature arrangements may be used, such as maintaining each of evaporator 56 , hollow transport tube 54 and reservoir 50 at the same temperature.
[0069] Liquid metal 503 can be forced by the piston 51 into the evaporator 56 by means of an attached linear motion shaft 52 . The position of the linear motion shaft 52 can be changed either manually or optionally through an attached motor drive. By this means, liquid metal can be forced into the evaporator to replace liquid metal that is depleted through the metal evaporation process. The introduction of an optional level sensor 523 can be used to sense and regulate the position of the liquid metal surface 501 therein to maintain a constant metal evaporation rate at a fixed evaporator temperature sensed and controlled by the evaporator thermocouple 511 .
[0070] An optional conical nosecone with attached level sensor 521 can be inserted within the evaporator cylinder wall 522 . The conical nosecone section is used to provide dispersion of the evaporated metal flux to obtain uniform thickness deposition of the metal on the coated substrates. The angle of the nosecone is designed to simultaneously achieve optimum deposited metal thickness uniformity on the coated substrates together with low consumption of the liquid metal in the evaporation process. A leak-tight seal can be made using mating flat flanges 530 between the lip of the conical nosecone with attached level sensor 521 and the top lip of the evaporator crucible 56 .
[0071] In the preferred embodiment, the conical nosecone with attached level sensor 521 is preferably machined from a single piece of high purity graphite which is coated with a thin insulating layer of pyrolytic boron nitride (PBN). An electrically conducting level sensor contact point 524 is made by machining away a small area of the PBN coating on the graphite level sensor probe 523 . An electrical contact to the graphite nosecone and level sensor (not shown) can be made with an insulated threaded metal rod preferably made from refractory metal such as Molybdenum (Mo), Tantalum (Ta), or Tungsten (W) that attaches to a machined threaded hole through the PBN insulating layer into the conducting graphite of the nosecone with attached level sensor 521 . A second electrical contact can be made to the liquid metal 503 by means of a separate electrical wire contact 525 to the electrically conducting graphite wall of the cell body 500 . The electrical resistance between the level sensor probe contact point 524 and the liquid metal contact point on the cell body 525 is determined by the vertical height of the liquid metal 501 contained in the evaporator 56 . When the vertical height of the liquid metal 501 is below the level sensor contact point 524 , the electrical resistance between the probes is very high (open circuit). When the vertical height of the liquid metal 501 is equal to or above the level sensor contact point 524 , the electrical resistance between the probes is very low (short circuit). This liquid metal electrical contact switch is similar to that of a Mercury (Hg) switch used in thermostats that are used to control heating and cooling systems to regulate ambient room temperature. In a similar manner, the level sensor can be used to sense and control the position of the piston 51 by means of a linear actuator 52 to maintain a constant liquid metal height in the evaporator to maintain a constant metal evaporation rate at a fixed evaporator temperature. The use of the two level sensor probes to automatically control the liquid metal height in the evaporator by means of motor drive of the piston linear actuator is described in subsequent paragraphs.
[0072] Proper operation of the liquid metal evaporation source of the subject invention requires that the liquid metal is contained within the reservoir and does not leak past the piston. The diameter of the reservoir inner cylinder wall 502 must be slightly larger than the outer diameter of the cylindrical piston 51 to form a sliding leak-tight seal between these parts. For the case of a liquid metal that does not wet or react with the graphite reservoir cylinder 502 and the cylindrical piston 51 , containment of the liquid metal within the reservoir relies upon the surface tension of the liquid metal. Under certain design conditions, the liquid metal is prevented from flowing past the small gap separating the reservoir inner cylinder walls and the piston cylinder walls.
[0073] A quantitative expression is derived which relates the maximum permissible gap between the reservoir cylinder inner diameter and piston cylinder outer diameter to insure containment of the liquid metal within the reservoir by the surface tension of the liquid metal. Work must be done on the closed system in order to change the surface area of the liquid metal when it is forced into the gap between the reservoir cylinder and piston. The differential work required to increase the liquid metal surface area is given by
ⅆ G surface = γ ⅆ A ( Equation 2 ) = γ [ π D + π ( D + Δ ) ] ⅆ h ~ 2 γπ D ⅆ h ( Equation 3 )
where dG surface is the change in surface energy in the liquid metal, γ is the surface tension of the liquid metal, dA is the differential change in surface area of the liquid metal, D is the diameter of the piston, Δ is the small gap between the reservoir cylinder wall and piston cylinder wall, and dh is the differential vertical height change of the liquid metal within the gap Δ between the reservoir cylinder and piston cylinder.
[0074] The internal pressure of the liquid metal at the gap between the reservoir and piston results from hydrostatic pressure due to the vertical height difference of the liquid metal surface 501 above the piston 51 and is given by
P=ρgh (Equation 4)
where P is the hydrostatic pressure, ρ is the density of the liquid metal, g is the gravitational constant, and h is the vertical height difference between the liquid metal in the evaporator above the piston surface.
[0075] The work performed by the hydrostatic pressure of the liquid metal forcing the liquid metal within the piston gap is given by
dG pressure =P[πDΔdh]=[ρgh][πDΔdh] (Equation 5)
[0076] Under equilibrium, the differential energies are the same. The threshold condition before the liquid metal will flow past the piston gap Δ is determined by setting Equations 3 and 5 to be equal and is given by
2γπ Ddh=[ρgh][πDΔdh] (Equation 6)
[0077] The maximum permissible gap Δ that can be used between the reservoir cylinder and piston walls can be determined from Equation 6 and is given by
Δ=2 γ/[ρgh] (Equation 7)
[0078] Thus the maximum permissible gap Δ is given by the liquid metal surface tension multiplied by two and divided by the hydrostatic pressure of the liquid metal exerted upon the piston surface. The design gap between the reservoir and the piston is therefore chosen to be smaller than that given by Equation 7 to insure sufficient margin so that the liquid metal will never penetrate past the open space gap separating the piston outer cylinder wall from the reservoir inner cylinder wall. This relation also determines the maximum permissible wear between the graphite walls of the reservoir inner cylinder and piston outer cylinder before leakage of liquid metal will occur past the piston.
[0079] Example: Calculate the maximum permissible gap Δ required for a leak-tight seal between the reservoir inner cylinder and piston outer cylinder for Ga where the vertical height of the liquid metal in the evaporator is 30 cm above the piston. Substituting into Equation 7 gives
Δ = 2 ( 720 dynes / cm ) /
[ 5.9 gm / cm 3 980 cm / s 2 30 cm ]
= 0.0083 cm ( Equation 8 )
[0080] A machined sliding gap Δ=0.003-0.004 cm can be achieved between a reservoir inner cylinder and piston outer cylinder with nominal diameters of 10 cm using a so-called “sliding fit” between these parts. This machining tolerance provides a good design margin by a factor of 2 to obtain a leak-tight seal for Ga between the reservoir and piston using a vertical height of 30 cm for Ga in the evaporator above the piston. Experimental measurements performed on a model reservoir are also in excellent agreement with this calculation.
[0081] Turning next to FIG. 6 shown is the preferred embodiment of a liquid metal evaporation source 600 according to the subject invention. In this configuration, evaporator 66 and hollow transport tube 64 may be attached to the reservoir body 60 using threaded assemblies that are leak-tight to the liquid metal or by any other known leak-tight attachment means. Concentric evaporator 66 and attached hollow transport tube are joined at right angles to the axis of the reservoir cylinder 60 preferably by a threaded joint 631 . Flat mating flanges 633 on the threaded end of the hollow transport tube 64 and threaded reservoir cylinder body 60 will insure a leak-tight seal. Liquid metal 603 will pass through the reservoir body into the hollow transport tube 64 by a co-joining right angle passageway 632 machined into the reservoir cylinder body.
[0082] During operation this preferred embodiment of the subject invention shown in FIG. 6 is similar to that of alternate embodiment shown in FIG. 5 . That is, liquid metal evaporator 66 , hollow transport tube 64 , and hollow reservoir cylinder 60 are machined from a refractory material, preferably high-purity densified graphite that is optionally coated with a thin layer of chemical vapor deposited pyrolytic graphite (PG) or pyrolytic boron nitride (PBN). Likewise, a close-mating piston cylinder 61 is machined from the same or similar refractory material to make a leak-tight seal for the liquid metal 603 held in the reservoir cylinder 60 . The evaporator wall 622 , the hollow transport tube wall 642 , and the hollow reservoir wall 602 which contain the liquid metal 603 are preferably machined in cylindrical form to minimize the gaps between the reservoir piston 61 and optional nosecone and level sensor 621 . The liquid metal will be contained within the reservoir cylinder by the surface tension of the liquid metal under certain conditions wherein the gap separating the walls of the reservoir inner cylinder 602 and the piston outer cylinder 61 are machined to be within required tolerances as previously described.
[0083] Evaporator heater element 67 , hollow transport tube heater element 65 , and reservoir heater element 63 are respectively used to heat by infrared radiation the walls of evaporator 66 , hollow transport tube 64 , and reservoir 60 to prevent solidification of the liquid metal in any part of cell 600 . Graphite has efficient black-body radiation absorption that will reduce the required heater element powers to achieve nominal operating temperatures for the cell in comparison to other refractory materials such as pyrolytic boron nitride (PBN) or SiO 2 (quartz). Evaporator thermocouple 611 , hollow transport tube thermocouple 612 , and reservoir thermocouple 613 are used to independently sense and control the respective temperatures in the three temperatures in the three separate temperature zones. Also optional radiation shields typically made from Tantalum (Ta) foil (not shown) and optional water-cooling jacket (not shown) to surround the heater elements and provide thermal isolation of the respective temperature zones may be used in accordance with the invention. Under normal operation, evaporator 66 is preferably held at the highest temperature to vaporize the liquid metal, while hollow transport tube 64 is held at some intermediate temperature and reservoir 60 is held at the lowest temperature, preferably just slightly above the melting point of the metal material being used for deposition. Of course, other temperature arrangements may be used, such as maintaining each of evaporator 66 , hollow transport tube 64 and reservoir 60 at the same temperature.
[0084] Liquid metal 603 can be forced by the piston 61 into the evaporator 66 by means of an attached linear motion shaft 62 . The position of the linear motion shaft 62 can be changed either manually or optionally through an attached motor drive. By this means, liquid metal can be forced into the evaporator to replace liquid metal that is depleted through the metal evaporation process. The introduction of an optional level sensor 623 can be used to sense and regulate the position of the liquid metal surface 601 therein maintaining a constant metal evaporation rate at a fixed evaporator temperature sensed and controlled by the evaporator thermocouple 611 .
[0085] An optional combined conical nosecone with attached level sensor 621 can be inserted within the evaporator cylinder wall 622 . The conical nosecone section is used to provide dispersion of the evaporated metal flux to obtain uniform thickness deposition of the metal on the coated substrates. The angle of the nosecone is designed to simultaneously achieve optimum deposited metal thickness uniformity together with low consumption of the liquid metal in the evaporation process. A leak-tight seal can be made using mating flat lip flanges 630 between the conical nosecone with attached level sensor 621 and the top lip of the evaporator crucible 66 .
[0086] In the preferred embodiment, the conical nosecone with attached level sensor 621 is preferably machined from a single piece of high purity graphite which is coated with a thin insulating layer of pyrolytic boron nitride (PBN). An electrically conducting level sensor contact point 624 is made by machining away a small area of the PBN coating on the graphite level sensor probe 623 . An electrical contact to the graphite nosecone and level sensor (not shown) can be made with an insulated threaded metal rod preferably made from refractory metal such as Molybdenum (Mo), Tantalum (Ta), or Tungsten (W) that attaches to a machined threaded hole through the PBN insulation into the conducting graphite. A second electrical contact can be made to the liquid metal 603 by means of a separate electrical wire contact 625 to the electrically conducting graphite wall of the cell body 600 . The electrical resistance between the level sensor probe contact point 624 and the liquid metal contact point 625 is determined by the vertical height of the liquid metal 601 contained in the evaporator 66 . When the vertical height of the liquid metal is below the level sensor contract point 624 , the electrical resistance between the probes is very high (open circuit). When the vertical height of the liquid metal 601 is equal to or above the level sensor probe, the electrical resistance between the probes is very low (short circuit). This liquid metal electrical contact is similar to that of a Mercury (Hg) switch used in thermostats that are used to control heating and cooling systems to regulate ambient room temperature. In a similar manner the level sensor can be used to sense and control the position of the piston 61 by means of a linear actuator 62 to maintain a constant liquid metal height in the evaporator to maintain a constant metal evaporation rate at a fixed evaporator temperature. The use of the level sensor to automatically control the liquid metal height in the evaporator by means of motor drive of the piston linear actuator is described in subsequent paragraphs.
[0087] An advantage of this cell configuration is clearly shown in FIG. 6 . Specifically, the large capacity of external reservoir 60 for liquid metal 603 may be made independently as large as practical since reservoir 60 may be placed outside the source flanges of the MBE or vacuum deposition system. This enables the system to be loaded with a very large supply of liquid metal 603 to allow continuous operation of the MBE system for a very long period (e.g. one year or more). In addition, liquid metal 603 may be lowered back into reservoir 60 prior to venting the vacuum system to atmospheric pressure before, for example, periodic MBE maintenance thus preventing extensive oxidation of the metal source.
[0088] Another important benefit of the right angle evaporator/reservoir design is that it reduces the maximum hydrostatic pressure of the liquid metal exerted upon the piston as given by the expression in Equation 7. This is because the piston is positioned above the lowest point of the liquid metal contained in the reservoir cylinder walls 602 . In contrast, the full hydrostatic pressure of the liquid metal is exerted on the piston in the fully concentric cell design shown in FIG. 5 since the piston is at the lowest vertical point in this configuration. Thus the right angle reservoir design increases the permissible gap tolerance requirement between the reservoir cylinder walls 602 and the piston cylinder walls 61 which enables very large capacity liquid metal reservoirs to be constructed. In addition, the maximum force exerted on the piston 61 and piston linear actuator 62 is also reduced. This will reduce the force requirement ratings on the linear actuator and motor drive required for automatic control of the piston position.
[0089] Referring next to FIG. 7A , shown is an enlarged schematic of the preferred embodiment of the nosecone cap with an attached liquid metal level sensor probe 700 according to the present invention. A cross-section of the conical nosecone with attached level sensor probe 70 is shown in FIG. 7A . This part is preferably made from electrically and thermally conductive graphite and is coated with preferably a thin pyrolytic boron nitride (PBN) layer for insulation of the nosecone with attached level sensor probe from the graphite evaporator sidewalls 522 ( FIG. 5 ) or 622 ( FIG. 6 ). The coefficient of thermal expansion of the graphite is chosen to be similar to PBN to prevent cracking or delamination of this insulating layer from the nosecone with attached level sensor probe. The conical orifices in the nosecone with outer diameter 76 and inner diameter 77 and angular taper 74 is used to provide dispersion of the metal evaporation to achieve desired uniformity of metal deposition over the coated substrates. The conical orifice diameters and taper angle are also chosen to achieve efficient utilization of the liquid metal in the metal evaporation process. The level sensor probe 71 is attached to the bottom of the nosecone part and is inserted into the liquid metal contained within the evaporator. An electrical contact point 75 to the liquid metal is formed by machining away a small area of the PBN insulating layer covering the graphite. Electrical contact to the sensor probe is provided by a machined threaded hole 73 that is attached to an insulated refractory metal rod (not shown) made from Molybdenum (Mo), Tantalum (Ta), or Tungsten (W). A flat lip flange 72 is used to seal the nosecone to a mating flat lip flange on the evaporator crucible. This prevents any evaporation of the liquid metal through these flanges which is problematic if the metal comes in contact with the Ta top filament heaters 57 ( FIG. 5 ) or 67 ( FIG. 6 ) which can cause the filament heaters to burn out prematurely. The two flat flanges are joined together using insulated threaded rods or screws (not shown) which attach to the threaded holes 73 to provide a leak-tight seal.
[0090] A plan view of the nosecone and level sensor is shown in FIG. 7B . It is seen that the extended level sensor probe is preferably formed in the shape of a partial annular ring or crescent which inserts into the liquid metal in the evaporator. The outer radius of the level sensor probe is machined to form a close fit with the inner cylinder walls of the evaporator crucible. This will improve radiant heat transfer to the level sensor probe due to its close proximity with the evaporator crucible sidewall in order to prevent condensation of liquid metal droplets on the level sensor probe. Metal droplets that condense on the level sensor probe can be a source of defects in the deposited metal films on the coated substrates. A thin arc is machined through the insulating PBN layer at a fixed distance below the nosecone bottom orifice 77 to provide the contact point 75 for the level sensor probe. This machined thin arc contact point will provide the same relative liquid metal contact point with respect to the top of the evaporator even if the nosecone is rotated slightly (e.g. within 60°) from its nominally intended installation position. This will insure reproducible positioning of the liquid metal height in different cells to produce similar metal evaporation characteristics. It is preferable to locate the level sensor point below the bottom nosecone orifice so that the nosecone can be maintained at a higher temperature compared to the liquid metal that is evaporated. This will prevent condensation of small metal droplets on the nosecone that can fall back into the liquid metal which can cause defects in the deposited metal films. This metal droplet formation is the origin of so-called “oval defects” that are found in the growth of GaAs by MBE and must be avoided. The level sensor contact position 75 can also be adjusted to reduce the volume of liquid metal contained within the evaporator crucible. Smaller volume capacity of liquid metal within the evaporator crucible will enable faster thermal response of the evaporator to effect changes in the metal evaporation rates if desired. Preferably, three threaded holes 73 are formed in the bottom of the flat sealing lip flange on the nosecone. Insulated threaded rods or screws made from refractory metal (not shown) are used to join together the lip flange to the flat lip flange on the top of the evaporator crucible to provide a leak-tight seal.
[0091] The height of the liquid metal within the evaporator crucible can be determined by use of the level sensor probe. One electrical contact to the liquid metal is made by contact of a conducting wire 525 ( FIG. 5 ) or 625 ( FIG. 6 ) to the electrically conductive graphite cell body containing the liquid metal. When the vertical height of the liquid metal is below the contact point 75 on the level sensor, the resistance between the two probes will be very high (open circuit). Therefore under the open circuit condition, it is known that the liquid metal is below the desired height in the evaporator crucible. Conversely, when the vertical height of the liquid metal is equal to or above the level sensor contact point 75 , the resistance between the two probes is very low (short circuit). Thus by moving the piston in the reservoir up and down slightly, the liquid metal height can be very accurately set to exactly the height of the contact point 75 on the level sensor probe. By this means, very reproducible metal evaporation rates can be maintained at a fixed evaporator temperature over the life of the charge of liquid metal contained within the evaporator. The piston position can be set either manually by measuring the resistance between the two probes or automatically using a simple motor control circuit as described in the next paragraphs.
[0092] Turning now to FIG. 8 , shown is a schematic diagram of a simple motor control circuit 800 which may be used in accordance with the present invention to control the motion of motor-driven linear feedthrough 52 or 62 and hence reservoir piston 51 or 61 . Preferably, control circuit 800 uses an op amp comparator 85 and an op amp unity gain buffer amplifier 84 to drive a low voltage relay 81 . DC motor 82 is connected to DC power supply 80 through the normally open (NO) switched contacts in relay 81 , and is in turn used to drive a linear motion shaft, for example, linear feedthrough 52 or 62 shown in FIGS. 5 and 6 , respectively, attached to reservoir piston 51 or 61 . In addition, a bias network 86 of four resistors 801 , 802 , 803 , 804 , preferably with values of 100 Ω, 100 Ω, 10 Ω and 5 Ω, respectively, is used to set the threshold level of op amp comparator 85 . When the liquid metal level sensor 87 is open circuit, the output of op amp comparator 85 is high thus energizing coil 88 in relay 81 , which applies voltage to DC motor 82 . Consequently, piston 51 or 61 will continue to push liquid metal 502 or 602 into evaporator 56 or 66 until the surface of the metal comes in contact with level sensor probes 524 or 624 . Thus, when liquid metal 503 or 603 touches level sensor probes 524 or 624 , a low resistance approximating a short circuit will develop that effectively forces the positive input of op amp comparator 85 to ground potential 83 . In this case, the output of op amp comparator 85 is low thus turning off relay coil 88 and removing voltage from DC motor 82 .
[0093] The operation of motor control circuit 800 will automatically regulate the height of liquid metal 503 or 603 so that it continuously remains in contact with level sensor probes 524 or 624 . Also, a slight amount of hysteresis can be built into motor-driven linear feedthrough 52 or 62 (typically<1 mm) to prevent oscillations therein due to vibrations in the liquid melt surface. Also, not shown is a protection mechanism to prevent piston 51 or 61 from continuously moving into reservoir 50 or 60 in the case where the wire leads to liquid metal sensor probes 524 or 624 are broken, thereby resulting in an open circuit. For example, a mechanical stop can be used to limit travel of piston 51 or 61 over a short period of time. Alternatively, a safety mechanism could use an electronic detection circuit to periodical measure the sensor probe resistance. That is, if the sensor resistance remained high for too long of a time period, then DC voltage to the motor would be disabled and an alarm would be activated.
[0094] Alternatively, the output voltage from relay 81 can be used as an input control signal for a stepper motor controller. The height of the liquid metal in the evaporator 501 or 601 could be precisely lowered within the evaporator relative to the level sensor contact point 524 or 624 . This could be used to effect reproducible reductions in metal evaporation rates by lowering the liquid metal height in the evaporator.
[0095] While the present invention has been described with reference to one or more preferred embodiments, such embodiments are merely exemplary and are not intended to be limiting or represent an exhaustive enumeration of all aspects of the invention. The scope of the invention, therefore, shall be defined solely by the following claims. Further, it will be apparent to those of skill in the art that numerous changes may be made in such details without departing from the spirit and the principles of the invention. It should be appreciated that the present invention is capable of being embodied in other forms without departing from its essential characteristics.
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A liquid metal evaporation source for use in Molecular Beam Epitaxy and related metal vacuum deposition techniques. An evaporator is maintained at a high temperature to evaporate a liquid metal, a reservoir for holding the liquid metal source is maintained at a temperature above the melting point of the metal but below the temperature in the evaporator, and a hollow transport tube connecting the evaporator and reservoir is maintained at a temperature between these temperatures. The reservoir is in the shape of a hollow cylinder with a close-fitting cylindrical piston which is used to force the liquid metal through the hollow transport tube into the evaporator. The liquid metal will not flow past the piston seal if a suitably small gap is formed between the piston and the reservoir walls wherein the surface tension of the liquid metal will exceed its hydrostatic pressure against the piston thus forming a leak-tight seal.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent Application No. 61/372,728, filed Aug. 11, 2010, which is incorporated herein in its entirety.
BACKGROUND
[0002] Pullulan was first used in breath films and this is still likely the largest application for this gum polysaccharide at the present time. In addition, pullulan is also used as a coating for tablets and has been successfully used to replace gelatin in gel capsules with the same heat sealing properties as gelatin. Pullulan achieved its GRAS status in 2002.
[0003] Pullulan is a water-soluble, extracellular polysaccharide produced by certain strains of the polymorphic fungus Aureobasidium pullulans, formerly known as Pullularia pullulans. The basic structure of pullulan was elucidated from the works of several researchers showing that it is a linear polymer of maltotriose subunits (glucose joined by α-(1→4) linkages) connected via α-(1→6) glycosidic linkages. Subsequently, it was established that there is a minor percentage of randomly-distributed maltotetraose subunits and these subunits were also joined by α-(1→6) linkages. The regular occurrence of α-(1→6) linkages kinks the structure of pullulan and interrupts what would otherwise be a linear starch amylose chain structure. The unique pattern of α-(1→6) linkages between maltotriose subunits gives the pullulan polymer distinctive physical properties, such as structural flexibility and high water solubility, resulting in distinct film- and fiber-forming characteristics such as: oxygen impermeability, edibility, biodegradability, and high solubility in water.
[0004] Pullulan, however, is expensive and cost restrictive compared to many other gum polymers. This high cost places significant economic and practical limits on its use. Certain prior art non-pullulan gum films, even at low concentrations or low film thicknesses, have the tendency to thicken the saliva, while still other prior art non-pullulan gum films tend to dissolve too slowly or not dissolve at all. These are unacceptable attributes and therefore, these prior art gums will not work as a replacement for pullulan. Certain commercial prior art pullulans, when dissolved at 25% w/w in water, have a viscosity at 20 RPM of 16,000-22,000 cP, are soluble in cold water, and produce a clear film that dissolves readily in the mouth with minimal thickening of the saliva. Further, many non-pullulan gum polysaccharides such as the standard grades of carboxymethylcellulose (CMC), methylcellulose, other cellulose derivatives, alginate, carrageenan, pectin, xanthan, etc., produce strong films at low gum concentrations but they are limited by their higher viscosity and, hence, they cannot be used at the same concentration as pullulan to achieve the same solids in a slurry prior to casting. Similarly, texture, mouthfeel, and rigidity differ between pullulan and other prior art non-pullulan materials, such as, gum polysaccharides.
[0005] As such, there is a need for a lower cost material with similar properties and functionalities as pullulan. The materials and methods disclosed herein provide a low cost solution to the problems described above.
SUMMARY
[0006] The disclosure herein relates generally to materials configured for use as pullulan replacements and their use in various applications such as breath films, films for drug delivery, and other edible films and coating applications. The materials and methods disclosed herein are configured to mirror the properties and functionalities of pullulan, without incurring the high cost and while avoiding one or more of the disadvantages or prior art materials. For example, in one embodiment, the material disclosed herein comprises a film forming material and one or more of soluble filler, standardizing, or texture altering ingredients, wherein the material is blended such that its properties and functionalities are similar to pullulan.
BRIEF DESCRIPTION OF THE DRAWING
[0007] FIG. 1 shows pictures of the pullulan control film and Replacements C & D.
DETAILED DESCRIPTION
[0008] One aspect of the invention is a material that can replace some or all of pullulan's unique properties and functionalities. Thus, any given embodiment of the invention may not necessarily replace all of pullulan's functionalities in a given application, but would be an improvement in at least one functional area normally recognized as being a defining characteristic or particular advantage of pullulan. For example, the invention may provide a replacement for pullulan by mimicking functionalities such as tensile strength, clarity, solubility of an initial product, solubility of the end use application product, texture, viscosity, oxygen impermeability, edibility, biodegradability, high water solubility, or similar properties. For example, the invention may have different solubility or clarity compared to pullulan while matching other properties, such as tensile strength or viscosity.
[0009] A further aspect of the invention includes novel methods of preparing or physically modifying blended materials to produce unique properties and functionalities. Thus, where one aspect of the invention calls for mirroring, at least one aspect, of pullulan, also disclosed are materials with unique properties created by preparing, physically modifying, and/or blending starting materials to produce unique properties and functionalities.
[0010] For example, in one embodiment, when the materials are incorporated into a final product, the solubility of the final product is similar to, or improves upon, the solubility of the same final product containing pullulan.
[0011] The material of the invention may be used in such applications as breath or flavor strips, tablet coatings, gel caps, tobacco products, films for cheese or spice flavor delivery, films as barriers in food products, non-food products including industrial, personal care, and pharmaceutical products.
[0012] Certain commercial prior art pullulans, when dissolved at 25% w/w in water, have a viscosity at 20 RPM of 16,000-22,000 cP, are soluble in cold water, and produce a clear film that dissolves readily in the mouth with minimal thickening of the saliva. Many other gum polysaccharides such as the standard grades of carboxymethylcellulose (CMC), methylcellulose, other cellulose derivatives, alginate, carrageenan, pectin, xanthan, etc., produce stronger films at much lower gum concentrations but they are limited by their higher viscosity and, hence, they cannot be used at the same concentration as pullulan to achieve the same solids in a slurry prior to casting. Similarly, texture, mouthfeel, and rigidity differ between pullulan and other prior art non-pullulan materials, such as, gum polysaccharides. As such, the materials of the invention include additional ingredients in order to overcome these deficiencies. For example, certain embodiments include fillers, standardizing, or texture-altering ingredients, blended in certain concentrations, to the main film forming materials to achieve properties and functionalities similar or equivalent to pullulan.
[0013] By way of non-limiting example, pullulan Replacement A comprises a main film forming material comprising approximately from about 1.5% to about 60% of a gum, such as cellulose gum, methylcellulose, other cellulose derivatives, alginate, propylene glycol alginace, xanthan gum, pectin, carrageenan, starch or a blend or combination thereof; and about 15% to about 75% of soluble filler and/or texture altering ingredient(s) comprising of a monosaccharide, disaccharide, oligosaccharide, dextrins, low viscosity gums such as gum arabic, inulin, larch, or a blend or combination thereof. Among other properties, this combination serves to weaken the film creating a material with strength similar to that of the pullulan film.
[0014] As another example, pullulan Replacement B, a sugar free version, comprises a main film forming material approximately from about 1.5% to about 60% of a gum such as cellulose gum, methylcellulose, alginate, propylene glycol alginate, xanthan gum, pectin, carrageenan, or a blend or combination thereof; and about 15% to about 75% of soluble fillers and/or film texture altering ingredients comprising of a sugar alcohol [for example, maltitol, sorbitol, xylitol, mannitol, erythritol, etc.], and/or low viscosity gums such as gum arabic, inulin, larch, or a blend or combination thereof. This combination serves to weaken the film creating a material with, among other features, a strength similar to that of the pullulan film
[0015] A further example, pullulan Replacement C, comprises a main film forming material comprising approximately from about 50% to about 98% of a gum, such as low viscosity cellulose gum, methylcellulose, hydroxypropylmethylcellulose and other cellulose derivatives, a low viscosity guar gum, alginate, propylene glycol alginate, xanthan gum, pectin, carrageenan, starch or a blend or combination thereof; and about 1.5% to about 60% of soluble fillers, standardizing and/or texture altering ingredients comprising of a sugar and sugar equivalent caloric ingredients such as a monosaccharide, disaccharide, oligosaccharide, dextrins, starch hydrolyzate or a blend or combination thereof. This combination creates materials with, among other features, viscosity, tensile strength, solubility, and sensory properties optimized to mirror pullulan properties and functionalities. In one particular embodiment, the material comprises about 96% hydroxypropylmethlycellulose (HPMC) about 3% CMC and about 1% maltodextrin.
[0016] As another example, pullulan Replacement D, a sugar free version, comprises a main film forming material approximately from about 50% to about 98% of a gum such as low viscosity cellulose gum, methylcellulose, hydroxypropylmethylcellulose and other cellulose derivatives, low viscosity guar gum, alginate, propylene glycol alginate, xanthan gum, pectin, carrageenan, or a blend or combination thereof; and about 1.5% to about 60% of sugar-free soluble fillers, standardizing and/or texture altering ingredients comprising of a sugar alcohol [for example, maltitol, sorbitol, xylitol, mannitol, erythritol, etc.], and/or low viscosity gums such as gum arabic, inulin, larch, arabinoxylan, hydrolyzed guar, resistant maltodextrin, or a blend or combination thereof. This combination creates materials with, among other features, viscosity, tensile strength, solubility, and sensory properties optimized to mirror the properties and functionalities of pullulan. For example, one embodiment comprises about 94% HPMC, about 1% CMC, and about 5% low viscosity guar.
[0017] In a further aspect of the invention, the materials may include anti-foaming ingredient. This will ensure that the materials disclosed herein have foaming characteristics similar to pullulan. For example, any of the Replacements A-D may also include an anti-foaming ingredient.
[0018] As shown in Table 1, the viscosity of pullulan can be matched by proper selection and blending of the gum and non-gum components disclosed herein. For example, both pullulan Replacements C & D matched the viscosity of the pullulan control of approximately 18,000 cP average at 25% concentration [w/w in water]. Viscosity is one critical factor in casting because it affects the uniformity and evenness of the cast, and influences the mouthfeel of the finished film when it dissolves in the mouth. As mentioned, certain prior art non-pullulan gum films, even at much lower concentrations or lower film thicknesses, have the tendency to thicken the saliva, while still other prior art non-pullulan gum films tend to dissolve too slowly or not dissolve at all. These are unacceptable attributes for a film and coating and therefore, these prior art gums will not work as a replacement for pullulan, unlike the blended compositions disclosed herein.
[0019] FIG. 1 shows pictures of the pullulan control film and Replacements C & D. The 25% solution of Replacements C & D both have a light yellow tinge in contrast to the pullulan control, which was water clear, however, their finished films are very comparable to the control in color and clarity. These exemplary films were made using the Mathis LabCoater/Dryer where the solution was cast at 20 mils [0.51 mm] and dried using a 2-stage drying process first at 130° F. and then at 175° F. However, without deviating from the invention, other techniques known to those of skill in the art could also be used to prepare the materials disclosed herein.
[0020] Table 2 compares the tensile strengths of certain examples of the materials disclosed herein and a pullulan control, measured longitudinally [along the direction of the cast] and transversally [across the cast] using the TA-XTP plus Texture Analyzer on a 1″×4″ [2.54 cm×10.16 cm] strip of film. These results demonstrate that embodiments such as Replacements C & D match the tensile strength of the pullulan of about 13,000 g of force.
[0021] Table 3 compares the dissolution of the pullulan control film and certain examples of the materials disclosed herein. Strips of each material, measuring 25 mm×25 mm, were placed in 100 ml of water and stirred using a magnetic stir bar. As shown, the dissolution times for Replacements C & D are similar to the pullulan control. The sensory results in Table 4 also demonstrate that the attributes of the materials disclosed herein, such as thickness, mouth coating, and disintegration in the saliva were the same as control, while taste demonstrated only a slight deviation. Table 5 further shows the similarities between the viscosity of pullulan and the materials disclosed herein.
[0000]
TABLE 1
Viscosity of pullulan and pullulan replacements at 25% concentration.
Average Viscosity, cP
Pullulan Control
18000
Pullulan Replacement C
18300
Pullulan Replacement D
18500
[0000]
TABLE 2
Tensile strengths of pullulan control and the pullulan replacement films.
All were 25% solution cast at thickness of 20 mils [0.51 mm]
Pullulan Control
g Force
Pullulan Control
g Force
Longitude 1
14784.7
Transverse 1
12027.8
Longitude 2
14704.2
Transverse 2
11846.8
Longitude 3
12676.6
Transverse 3
12951.6
Longitude 4
13274.9
Transverse 4
15206.3
Average
13860.1
Average
13008.1
S.D.
1050.5
S.D.
1543.3
Pullulan Replacement C,
Pullulan Replacement C,
Batch 1
Batch 1
Longitude 1
11169.3
Transverse 1
12670.7
Longitude 2
13744.2
Transverse 2
12309.3
Longitude 3
12054.3
Transverse 3
11955.6
Longitude 4
12891.5
Transverse 4
16894.4
Average
12464.8
Average
13457.5
S.D.
1105.4
S.D.
2309.8
Pullulan Replacement C,
Pullulan Replacement C,
Batch 2
Batch 2
Longitude 1
13805.5
Transverse 1
14812.6
Longitude 2
13470.5
Transverse 2
15514.9
Longitude 3
11708.1
Transverse 3
11588.5
Longitude 4
12453.2
Transverse 4
14279.2
Average
12859.3
Average
14048.8
S.D.
959.0
S.D.
1486.5
Pullulan Replacement D,
Pullulan Replacement D,
Batch 1
Batch 1
Longitude 1
14662.7
Transverse 1
12821.7
Longitude 2
12536.2
Transverse 2
13204.6
Longitude 3
11987.5
Transverse 3
14600.1
Longitude 4
15107.5
Transverse 4
15138.1
Average
13573.5
Average
13699.3
S.D.
1541.8
S.D.
1696.0
Pullulan Replacement D,
Pullulan Replacement D,
Batch 2
Batch 2
Longitude 1
13452.0
Transverse 1
12624.3
Longitude 2
14233.3
Transverse 2
14471.8
Longitude 3
12779.6
Transverse 3
15084.6
Longitude 4
13578.6
Transverse 4
15563.8
Average
13510.9
Average
14436.1
S.D.
595.8
S.D.
1287.9
[0000]
TABLE 3
Pullulan films dissolution time in minutes. Film dimension = 25
mm × 25 mm.
Pullulan
Pullulan
Pullulan
Replication
Control
Replacement C
Replacement D
1
3.0
2.8
2.7
2
2.0
2.9
3.6
3
3.0
3.3
2.0
4
3.8
2.8
1.6
5
2.9
3.1
2.1
Average
2.9
3.0
2.4
[0000]
TABLE 4
Sensory attributes of pullulan replacement films tested against pullulan.
A score of 0 indicates the same sensory attributes as the control.
Attribute
Pullulan Replacement C
Pullulan Replacement D
Thickness
0.18
−0.45
Mouth Coating
0.18
−0.27
Taste
−1
−1
Disintegration
−0.55
0.36
[0000]
TABLE 5
Viscosity of pullulan and pullulan replacements at 25% concentration.
Viscosity, cP
Pullulan
18050
Replacement A
18050
Replacement B
17600
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This disclosure relates generally to materials configured to replace pullulan and pullulan functionalities and their use in applications such as edible films, coatings, breath or flavor strips, tablet coatings, gel caps, tobacco products, films for cheese or spice flavor delivery, films as barriers in food products, and non food products including industrial, personal care and pharmaceutical products. In addition, the materials and methods disclosed herein are configured for use in similar products that do not incorporate pullulan but would benefit from pullulan-like properties and functionalities.
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BACKGROUND OF THE INVENTION
This present invention relates to compression, hermetic glass-to-metal seals and current feed-throughs. Such seals are commonly used as feed-throughs for signal conductors in hermetically sealed, metal cased capacitors, relays and other electronic components.
The invention has particular application in the manufacture of hermetic glass-to-metal seals for capacitors which handle high amperage current pulses, which may be AC or pulsating DC. It has been realized that hermetic glass-to-metal seals introduce heating and power loss when used as feed-throughs for signal conductors handling high amperage pulsating currents.
The purpose of this invention is to set forth improved compression-type, hermetic glass-to-metal seals which will provide significantly lower heating and power loss when used in high amperage pulsating current applications than prior art.
The following discussion will describe the manufacture of a compression, hermetic glass-to-metal seal, used in a metal cased hermetically sealed capacitor. However, it will be understood that the formation and use of a compression, hermetic glass-to-metal seal in accordance with the present invention is widely applicable to analogous structures, metal cased relays and other hermetically sealed electronic components.
The art of manufacturing compression, hermetic glass-to-metal seals is well-known and has been described by Mayer in U.S. Pat. No. 3,035,372. Such seals comprise an outer metal compression ring which contains an annular glass button through which is disposed a coaxial conductor assembly including an outer tube or eyelet and an inner conductor. Commonly the inner conductor is plain copper wire of a suitable gauge to carry the currents of the circuits involved. The outer tube or eyelet which surrounds the wire is used to obtain the essential glass to metal bond which is needed for hermeticity. Such compression seals are commonly manufactured in different manufacturing operations. In a first, high temperature stage, the ring, glass button, and tube are fired to form a unitary seal assembly. This assembly is mounted to a can such as a cylindrical tube containing the electrical components such as a capacitor such that the lead wire from the latter protrudes through the eyelet of the preassembled seal. The capacitor case and seal are then soldered together in the second stage at a temperature much lower than the initial manufacture of the seal. The conductor is soldered to the eyelet in a similar manner.
Prior art calls for the outer member (1) to be made of common steel the glass member (2) to be selected from the potash soda or potash lead type and the inner member (3) to be made of nickel 52, an iron nickel alloy containing about 52% nickel and 48% iron.
Examination of the thermal expansion properties of the materials shows that the outer ring (1) has higher thermal expansion than either the glass or central member so that the glass is placed in radial compression. Nickel 52 has a coefficient of thermal expansion slightly lower than the glass. The result is that the outer ring (1) transmits radial compression into the glass (2) which is transmitted to the inner member (3). For glasses of the type mentioned such as Corning 9010 or 9013 a good bond can be made to nickel 52. The physical strength and hermeticity of the just described prior art is excellent, and the physical integrity and electrical performance for conduction of steady state direct electrical current of the just described seals is excellent.
With the increasing use of pulsating and alternating current in circuit design it has become evident that a significant loss of power occurs when high frequency signals must pass through the 52 alloy eyelet via the copper conductor. When sufficient signal energy exists, the eyelet temperature can possibly increase up to the point of melting the soft solder joint which is used to hermetically seal the copper lead wire conductor to the eyelet.
The resultant drain of power from these electronic circuits requires that the circuits deliver more power. This results in increased weight and size for these electronic or electrical devices and equipment to overcome the losses due to the the hermetic seal effects.
The losses are primarily ferro-magnetic and partially due to skin-effect or eddy current.
To overcome these losses we investigated available non-magnetic materials which could match suitable sealing glasses and have found that Hastelloy B alloy (consisting essentially of 65% nickel and 30% molybdenum) possesses an acceptably low coefficient of thermal expansion.
The construction of a seal with Hastelloy B proved entirely satisfactory and is the preferred embodiment of the present invention. Hastelloy B is a trademark of Cabot Corporation of Kokomo, Ind.
Investigation has shown that compression, hermetic glass-to-metal seals introduce heating and power loss when used as feed-throughs for signal conductors handling high amperage pulsating currents. These effects are now found to result from induction heating of the nickel 52 inner member or eyelet.
The cause of the heating is not precisely known, and might be falsely attributed to the construction of the capacitor or to dielectric heating of the glass seal or to any of the other components. An isolation test was performed in which it was discovered that the small nickel 52 eyelet having a conductor passed therethrough carrying a current was readily heated, particularly if the inside diameter of the aperture were relatively close to that of the diameter of the wire, as in seals of the present type. This heating mechanism was felt to be directly analogous to RF induction heating (i.e., magnetic induction heating, and eddy current induction heating, or some combination). Substitution of a non-magnetic stainless steel eyelet in this experiment resulted in virtually no heating whatsoever. However, a compression seal of this type cannot be constructed to use these results since stainless steel is unsuitable in glass to metal hermetic bonds because of its coefficient of thermal expansion is too high. A non-magnetic metal having a good capability of bonding to glass was desired; and also having a property of an acceptable thermal expansion coefficient. Of all alloy materials readily available, only the alloy Hastelloy B (consisting essentially of 65% nickel and 30% molybdenum) possessed an acceptably low coefficient of thermal expansion, was known to be non-magnetic and makes a good bond to glass. The construction of a seal with Hastelloy B proved entirely satisfactory and is the preferred embodiment of the present invention.
The selection of a material for use as the inner eyelet member is critical and such a material must have the following properties:
1. The material must be non-ferromagnetic.
2. The material must possess good chemical bonding properties during the sealing operation.
3. The coefficient of thermal expansion must be compatible with the glass to maintain hermeticity.
4. The elasticity characteristics of the alloy should be compatible with the glass so as to allow equalization of compressive forces created without setting up unduly high stesses.
5. The material must be relatively inexpensive.
It has been found that the alloy commonly known as Hastelloy B* has the properties required and is entirely suitable and the preferred metal alloy for use in the present invention. Hastelloy B is an alloy of about 64% nickel and 28% molybdenum with other percentages of alloying material being limited to about 1/2% carbon, 5% iron, 2.5% cobalt and 1% chromium. This alloy is widely used for its outstanding corrosion resistance. The coefficient of thermal expansion, of Hastelloy B is about 100 cm/cm×10 -7 /°C. and will bond very well to glasses such as Corning 9013 and 9010 which have thermal coefficients of expansion of about 95 cm/cm×10 -7 /°C.
Testing has also shown that the use of a non-ferromagnetic outer ring further reduces the effects of induction heating.
In the present invention a non-magnetic outer ring made of monel or non-magnetic stainless steel 304 is used to reduce induction heating. The inner member is a hollow or solid tube. The glass is Corning 9013 and 9010.
In the specifications, the following abbreviations may be used in the following descriptions.
Nickel=Ni
Molybdenum=Mo
Tungsten=W
Hastelloy=Hastelloy B, TM of Cabot Corporation. (Other Hastelloy trademarked products are not included.)
Platinum=Pt
Palladium=Pd
The following units are used through this description: coefficient of linear expansion-cm/cm/°C.×10 -7 . Percentage compositions of alloys given herein in weight percent (w/o), in accordance with common engineering practice. 300 Series steels, such as 304, refer to AISI designations.
Before any investigation to solve this problem was made, consideration was given to the use of copper-to-glass seals. Copper-to-glass seals, however, are not practical for the following reasons: the type of glass used with copper seals is soluable in solutions used in plating. Copper must be plated prior to the sealing step to ensure a good metal-to-glass bond. In addition, copper-to-glass seals do not maintain hermeticity after being exposed to temperature cycling.
SUMMARY OF THE INVENTION AND OBJECTS
It is the general object of the present invention to provide a compression glass to metal hermetic seal which will overcome the above limitations and disadvantages.
A further object of the invention is to provide a compression seal of the above character which is relatively free of inductive loss when passing pulsating currents. A further object of the invention is to provide a hermetic compression seal of the above character which is reliable in operation, having an excellent glass-to-metal bonding character, and which is inexpensive to construct and may be manufactured with non-critical procedures.
A further object of the invention is to provide a compression seal of the above character which is relatively free of power loss when passing pulsating currents. A further object of the invention is to provide a hermetic compression seal of the above character which is reliable in operation, having an excellent glass-to-metal bonding character, and which is inexpensive to construct.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a capacitor incorporating a hermetic glass to metal compression seal constructed in accordance with the present invention.
FIG. 2 is a cross-sectional view partially broken away of one of the compression seals of the component of FIG. 1.
FIG. 3 is an exploded view of the end seal and the capacitor construction of the capacitor of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1 and 3, there is shown a capacitor component which is constructed in accordance with the present invention and includes an outer metal case 10 surrounding a capacitor 12 which may be insulated from the case by a plastic sheath 14. The capacitor has electrical leads consisting of wires 16,18 which pass through end seals 20. Each end seal is of the hermetic type in which an outer metal ring 22 compressively loads an intermediate disc 24 made of glass which surrounds and is fused to an eye of metal 26. The assembly of the unit involves physically locating the various parts together in the designed manner of assembly and subjecting the joints between the ring 22 and the can 10 to RF or other heating so as to fuse a solder or brazing alloy to join these parts. The eyelets at each end 26 are soldered to the respective leads 16,18 by direct application of flame heat.
Difficulties previously experienced due to heating of capacitor components, have finally been traced to heating of the eyelet. The metal eyelet serves as a transition from the glass to the lead itself and permits manufacture of the hermetic seal as a distinct and separate component part so that its manufacture is normally accomplished in a specialized glassworks, whereas the component itself may be manufactured as other electrical components and fused to the hermetic seal with brazing and soldering techniques. The eyelet must possess a number of desirable characteristics in order to be successful. It has been found that, when made of a material which is non-ferromagnetic at the temperature of operation, induction heating losses can be reduced to a level substantially below current experience and made capable for severe applications where reduction of component size to a minimum is essential.
It has been found that the alloy commonly known as Hastelloy B is entirely suitable for this purpose and is a preferred metal alloy for use in the present invention. Hastelloy B is an alloy of about 64% nickel and 28% molybdenum with other percentages of alloying material being limited to about 0.5% carbon, 5% iron, 2.5% cobalt and 1% chromium. This alloy is widely used for its outstanding corrosion resistance, particularly in as welded condition without further treatment and data is available for its use in that application, but relatively little electrical and magnetic data is available for use in the present application. Even so, Hastelloy B is found to possess a low Curie temperature, so that it is non-ferromagnetic at temperatures of operaton down to -65° C. In general, the coefficient of thermal expansion is about 100 cm/cm×10 -7 /°C. and when properly treated, bonds very well to glasses such as Corning 9013 and 9010 which have thermal coefficients of expansion of about 95 cm/cm×10 7 /° C. Hastelloy B is essentially paramagnetic at all temperatures of operation and is found to have low magnetic and electrical losses. Platinum, palladium, and nickel-tungsten alloy are also expected to be operable in this invention but possess one or more disadvantages, usually relating to cost and availability.
The following analysis is based upon a review of the literature and is given in aid of understanding the scope of the invention and the way that the useful materials can be distinguished. Hastelloy B has an excellent induction heating characteristic from the view of RF heating. RF heating has a depth of penetration which is related to the bulk resistivity and magnetic permeability as a function of temperature in such a way that as the temperature goes up, the resistivity should go up, which is true for Hastelloy B. Also, as the temperature goes up, the magnetic permeability goes down, so as to give greater penetration. Induction heating also depends on the third power of the magnetic field concentration so that it is particularly important that the penetration be good so as to avoid high surface heating. While these factors may or may not be applicable in certain current carrying circumstances, they can become applicable as the strength of the field strength increases significantly. Platinum is expected to be somewhat less satisfactory in the above analysis, but still workable. Similar nickel-tungsten alloy and palladium characteristics are not available.
With respect to thermal expansion, Hastelloy B is found to be excellent since it is compatible with a wide range of available glasses. Platinum is also excellent as is palladium. Nickel-tungsten alloy is expected to be good-to-excellent based on predictions from the known expansion coefficients of nickel-tungsten, and the considerable similarity of the curve temperature curve in the phase diagrams of the nickel-tungsten systems to nickel-molybdenum.
With respect to bonding to glasses, the Hastelloy B is found to be excellent, particularly when assembled with relatively conventional manufacturing technology as will be briefly outlined hereinafter. Both the platinum and palladium have known bonding characteristics which are at least fair. Nickel-tungsten alloy bonding characteristics are not known. The electrical properties of the metal alloy of the eyelet include a resistivity that is as low, since it is the major source of I 2 R heating, if the configuration demands the eyelet to carry current. However, if the eyelet is an intermediate section surrounding a high conductivity copper lead, for example, its I 2 R loss will be low in any event, so that such a coaxial structure is to be desired. The coaxial configuration of Hastelloy B eyelet with a high conductivity lead such as copper is excellent. In this connection, it might further be mentioned that the electrical resistivity plays several roles, and the exact mechanism for a particular signal may be different than for other signals. In that connection, it is found that it is desirable that the electrical resistivity be high in order to minimize eddy current losses. On this ground it would appear that a composite of a Hastelloy eyelet and a copper lead is the most satisfactory combination from the point of view of obtaining a non ferro-magnetic material to eliminate the hysteresis loss of both the stress and rotational type, that the eyelet resistivity is high to minimize eddy current losses by induction; that the cost of these materials is quite low; and that the thermal coefficient of expansion and temperature dependence thereof is compatible with glass.
The eyelet alloy must exhibit good chemical resistance to corrosion of a moderate type, and must possess good chemical bonding properties in glass sealing operations. It is useful if an oxide film can be formed to provide for a good glass to metal bond. In this connection, Hastelloy is good and platinum is fair.
The cost, of course, of Hastelloy B is relatively low, so as to make it an excellent candidate, whereas the cost of platinum is so high as to make it prohibitive in all but the most unusual situations.
The electromagnetic stability of all of these materials is high, so that this is not a factor; nor is the density, thermal conductivity, thermal diffusion, or specific heat. The formability of platinum is excellent whereas that of Hastelloy B is only fair.
The elasticity characteristics of the alloy should be compatible with the glass disc and with the outer compression ring, so as to allow equalization of compressive forces created without setting up unduly high stresses. In this application, Hastelloy B is found to be good, while the elasticity properties of platinum in this connection are not known even though its tensile data would appear to be good, and ductibility appear to be at least fair. It must be appreciated that the chemical bonding and thermo elastic properties of Platinum contain a sufficient number of variables, therefore it is difficult to predict, much less find, an alloy which is assuredly satisfactory. Thus, it is a surprising result that this relatively common alloy, Hastelloy B, should possess all of the properties which are required for a good seal, possess relatively few, if any, disadvantages. It is found that the combination of a simple outer seal ring with the glass and Hastelloy B material results in an exceptionally high quality seal which has no chemical or mechanical or electrical disadvantages insofar as the present testing admits.
It might be mentioned that Hastelloy B is a relatively old alloy, being known for about forty years at the time of this writing. However, in its initial version was difficult to obtain with controlled silicon and carbon content, which can prevent precipitation of carbides. This has been largely overcome in Hastelloy B-2. This property, however, is not relied upon and either the older Hastelloy B-1 or the newer Hastelloy B-2 are satisfactory.
Generally, the metal preparation includes passing the Hastelloy through a hot, high humidity hydrogen atmosphere to act as a reducing media and create a good bonding surface (to glass).
In addition to essential reduction of heat achieved by substitution of a non-ferromagnetic metal or alloy in the eyelet, it is found that a further induction heating reduction is achieved by substituting a non-ferromagnetic stainless steel such as SS 304 as the material of which the outer compression ring is made. In order to obtain the desired compression the thermal coefficient of expansion should remain high. Stainless steel 304 at 190 cm/cm/°C. -7 is satisfactory.
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Glass-to-metal hermetic seal of the compression type in which a central metal eyelet is sealed to a central conductor, the eyelet being bondable to and having a coefficient of expansion characteristic compatible with glass in which the eyelet is made non-ferromagnetic to eliminate unwanted induction heating and losses in pulsatory current carrying operation. The method of forming the seal is disclosed.
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BRIEF DESCRIPTION OF THE INVENTION
This invention relates generally to transient overvoltage protection devices. More particularly, it relates to electrical connectors with an overvoltage protection feature.
BACKGROUND OF THE INVENTION
All types of conductors are subject to transient voltages which potentially disable unprotected electronic and electrical equipment. Transient incoming voltages can result from lighting, electromagnetic pulses, electrostatic discharges, or inductive power surges.
More particularly, transients must be eliminated from electrical connectors commonly used in radar, avionics, sonar and broadcast. The need for adequate protection is especially acute for defense, law enforcement, fire protection, and other emergency equipment. A present approach to suppressing transients in connectors is to use silicon p-n junction devices. The p-n junction device is mounted on the connector contact; it serves as a dielectric until the voltage surge reaches a sufficient value to generate avalanche multiplication. Upon avalanche multiplication, the transient is shunted through the silicon device to the connector housing.
Several problems are associated with this prior art solution and other approaches which analogously use Zener diodes, varistors, and gas discharge tubes. Mounting the devices on the connector is difficult. Similarly, since the discrete devices are mounted to one another, they may not withstand hostile physical environments. Also, prior art devices are relatively heavy.
The electrical characteristics of prior art devices allow for improvement. An ideal device would have the capability of handling high energy and possess a response time in the sub-nanosecond range.
OBJECTS AND SUMMARY OF THE INVENTION
It is a general object of the present invention to provide an overvoltage protection apparatus.
It is a related object of the invention to provide an overvoltage protection apparatus which is not mounted on a conductor, but is moldably designed with the conductor.
A related object of the invention is to provide an overvoltage protection apparatus which eliminates discrete connection with the conductor and thereby provides a moldable and rugged design.
A further related object of the present invention is to provide an overvoltage protection apparatus which is lightweight.
Another object of the invention is to provide an overvoltage protection apparatus capable of handling high energy.
Yet another object of the invention is to provide an overvoltage protection apparatus with a sub-nanosecond response time.
These and other objects are achieved by a connector which includes a plurality of leads and a conductive plate which includes a number of bores extending through it. The leads are spaced from the walls of the bores. A quantum mechanical tunneling material is placed between the leads and the walls of the bores in order to support the leads. This configuration serves to connect the leads to the plate by quantum mechanical tunneling when the voltage between the leads and the plate exceeds a predetermined voltage.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:
FIG. 1 is a perspective view of a simplified connector using the apparatus of the present invention.
FIG. 2 is an enlarged cross-sectional view of a bore, lead, and overvoltage protection material from a connector taken along the line 2--2 of FIG. 1.
FIG. 3 is a perspective view of a simplified embodiment of the overvoltage protection apparatus of the present invention.
FIG. 4 is a perspective view of an alternate simplified embodiment of the overvoltage protection apparatus of the present invention.
FIG. 5 is a graph of clamp voltage versus volume percent conductive particles for the overvoltage protection material of the present invention.
FIG. 6 is an example test circuit for measuring the overvoltage response of a simplified embodiment of the present invention.
FIG. 7 is a graph of voltage versus time for a transient overvoltage pulse applied to a simplified embodiment of the present invention.
FIG. 8 is a graph of current versus voltage for a simplified embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Turning now to the drawings, wherein like components are designated by like reference numerals in the various figures, attention is initially directed to FIG. 1. A simplified power connector 10 is depicted therein. The connector 10 includes a number of leads 12 and a conductive plate 14. The conductive plate 14 includes a number of bores 16. The conductive housing 18 is shown in phantom. Composite material 20 is positioned between the leads 12 and the bores 16 of the conductive plate 14 in such a manner as to support the leads 12.
This simplified connector discloses the nature of the present invention. Of course those skilled in the art appreciate that a connector may include a number of components not disclosed herein, for instance, seals, grommets, shells, couplings, springs, and washers. Similarly, those skilled in the art will appreciate that connectors are used in a variety of voltage ranges and therefore they are configured for their specific application. For instance, in industrial applications such as portable welding equipment, construction equipment, and maintenance equipment, connectors operate in the range between 50 and 200 amps and up to 600 volts. Alternatively, mining equipment, airport runway lighting, and petrochemical industry equipment employs special environment connectors operating between 200 and 800 amps and 600 to 1000 volts. It will be appreciated by those skilled in the art that the invention disclosed herein is applicable in all of these applications.
Turning to FIG. 2, depicted therein is an enlarged cross-sectional view of the overvoltage protection device of FIG. 1, taken along the line 2--2. The figure discloses the precise nature of the composite material 20. Particularly, the figure discloses that the material 20 includes a number of particles 22 positioned within binder 28. The distance between particles 22 is depicted by space 26. The on-state resistance and the off-state resistance of the material 20 are determined by the inter-particle spacing 26 within the binder 28 as well as by the electrical properties of the insulating binder 28.
As the FIG. 2 suggest, the overvoltage protection apparatus of the present invention has a moldable design. As a result of this moldable design, the material is readily positioned contiguous with lead 12 and within bores 16.
This moldable design obviates problems in the prior art with mounting discrete elements such as diodes and varistors on a conductor. These prior art connections between the conductor and the discrete elements are not as rugged as the unitary moldable design of the present invention.
This moldable feature allows for simplified embodiments separate from embodiments relating to connectors 10. FIGS. 3 and 4 depict such embodiments. The device 11 includes a lead 12 which is surrounded by composite material (concentric member) 20. The composite material 20 is surrounded by a conductor jacket (second conductor) 24. The figures depict that the conductor jacket 24 is grounded. In FIG. 4, the conductor jacket 24 extends along a portion of the length of the axial conductor or lead 12.
Regardless of the particular embodiment utilized, the invention operates in the same manner. A transient on lead 12 induces the composite material 20 to switch from a high-resistance state to a low-resistance state thereby largely clamping the voltage to a safe value and shunting excess electrical current from the lead 12 through the composite material 20, through the second conductor 24 (or conductive plate 14) to system ground.
Electrically, the binder 28 serves two roles: first it provides a media for tailoring separation between conductive particles, thereby controlling quantum mechanical tunneling; second, as an insulator it allows the electrical resistance of the homogenous dispersion to be tailored.
During normal operating conditions and within normal operating voltage ranges, with the material 20 in the off-state, the resistance is quite high. Typically, it is either in the range required for bleed-off of electrostatic charge, ranging from one hundred thousand ohms to ten mega-ohms or more, or it is in a high resistance state in the 10 (to the 9th) ohm region.
Conduction by static bleed in the off-state and conduction in response to an overvoltage transient is primarily between closely adjacent conductive particles 22 and results from quantum mechanical tunneling through the binder 28 separating the particles. The electrical potential barrier for electron conduction between two particles 22 is determined by the separation distance 26 and the electrical properties of the insulating binder material 28. In the off-state this potential barrier is relatively high and results in a high electrical resistivity for the non-linear material. The specific value of the bulk resistivity can be tailored by adjusting the volume percent loading of the conductive particles in the binder, their particle size and shape, and the composition of the binder itself. For a well-blended, homogenous system, the volume percent loading determines the inter-particle spacing.
Application of a high electrical voltage to the material 20 dramatically reduces the potential barrier to inter-particle conduction and results in greatly increased current flow through the material via quantum-mechanical tunneling. This low electrical resistance state is referred to as the on-state of the non-linear material. The details of the tunneling process and the effects of increasing voltages on the potential barriers to conduction are described by the quantum-mechanical theory of matter at the atomic level, as is known in the art. Because the nature of the conduction is primarily quantum mechanical tunneling, the time response of the material to a fast rising voltage pulse is very quick. The transition from the off-state resistivity to the on-state resistivity takes place in the sub-nanosecond regime.
By way of example, if the diameter of the device in FIG. 4 is 0.02 inches (the conductors being spaced approximately 0.01 inches apart), a clamping voltage of 200 volts to 400 volts, an off-state resistance of ten mega-ohms at ten volts, and a clamp time less than one nanosecond may be achieved. Other clamping voltage specifications can be met by adjusting the thickness of the material formulation, or both.
An example of the material formulation, by weight, for the particular embodiment shown in FIG. 4 is 35% polymer binder, 1% cross linking agent, and 64% conductive powder. In this formulation the binder is Silastic 35 U silicon rubber, the crosslinking agent is Varox peroxide, and the conductive powder is nickel powder with 10 micron average particle size. The table shows the electrical properties of a device made from this material formulation.
______________________________________Electrical Resistance in off-state 10 (to the 7th) ohms(at 10 volts)Electrical Resistance in on-state 20 ohmsResponse (turn-on) time <5 nanosecondsCapacitance <5 pico-farads______________________________________
Those skilled in the art will understand that a wide range of polymer and other binders, conductive powdes, formulations and materials are possible. Other conductive particles which can be blended with a binder to form the non-linear material in this invention include metal powders of aluminum, beryllium, iron, gold, silver, platinum, lead, tin, bronze, brass, copper, bismuth, cobalt, magnesium, molybdenum, palladium, tantalum, tungsten and alloys thereof, carbides including titanium carbide, boron carbide, tungsten carbide, and tantalum carbide, powders based on carbon including carbon black and graphite, as well as metal nitrides and metal borides.
The primary function of the binder is to establish and maintain the inter-particle spacing of the conducting particles in order to ensure the proper quantum mechanical tunneling behavior during application of an electrical voltage. Accordingly, insulating binders can include but are not limited to organic polymers such as polyethylene, polypropylene, polyvinyl chloride, natural rubbers, urethanes, and epoxies, silicone rubbers, fluoropolymers, and polymer blends and alloys. Other insulating binders include ceramics, refractory material, waxes, oils, and glasses
While substantially an insulator, the binder's resistivity can be tailored by adding or mixing various materials which alter its electrical properties. Such materials include powdered varistors, organic semiconductors, coupling agents, and antistatic agents.
A wide range of formulations can be prepared following the above guidelines to provide clamping voltages from fifty volts to fifteen thousand volts. The inter-particle spacing, determined by the particle size and volume percent loading, and the device thickness and geometry govern the final clamping voltage.
Referring to FIG. 5, depicted therein is Clamping Voltage as a function of Volume Percent Conductor for materials of the same thickness and geometry, and prepared by the same mixing techniques as heretofore described. The off-state resistance of the devices are all approximately ten mega-ohms. The on-state resistance of the devices are in the range of 10 to 20 ohms, depending upon the magnitude of the incoming voltage transient.
FIG. 6 shows a test circuit for measuring the electrical response of a device made with materials of the present invention. A fast rise-time pulse, typically one to five nanoseconds, is produced by pulse generator 30. The output impedance 32 of the pulse generator is fifty ohms. The pulse is applied to the overvoltage protection apparatus 11 which is connected between the high voltage line 34 and the system ground 36. The voltage versus time characteristics of the non-linear device are measured at points 38, 40 with a high speed storage oscilloscope 42.
Referring now to FIG. 7, the typical electrical response of device 11 tested in FIG. 6 is depicted as a graph of voltage versus time for a transient overvoltage pulse applied to the device 11. In the figure, the input pulse 44 has a rise time of five nanoseconds and a voltage amplitude of one thousand volts. The device response 46 shows a clamping voltage of 360 volts in this particular example. The off-state resistance of the device tested in FIG. 7 is eight mega-ohms. The on-state resistance in its non-linear resistance region is approximately 20 ohms to 30 ohms.
FIG. 8 depicts the current-voltage characteristics of a device made from the present invention. The highly non-linear nature of the material used in the invention is readily apparent from the figure. Specifically, below the threshold voltage Vc the resistance is constant, or ohmic, and very high, typically 10 mega-ohms for applications requiring static bleed, and 10 (to the 9th) ohms or more for applications which do not require static bleed. On the other hand, above the threshold voltage Vc the resistance is extremely voltage dependent, or non-linear, and can be as low as approximately 10 ohms to 30 ohms for devices made from the present invention.
The process for fabricating the material of the present invention includes standard polymer processing techniques and equipment. A preferred process uses a two roll rubber mill for incorporating the conductive particles into the binder material. The polymer material is banded on the mill, the crosslinking agent (if required) is added, and then the conductive particles are added slowly to the binder. After complete mixing of the conductive particles into the binder, it is sheeted off the mill rolls. Other polymer processing techniques can be used including Banbury mixing, extruder mixing and other similar mixing equipment.
Thus, it is apparent that there has been provided, in accordance with the invention, an overvoltage protection device that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description.
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A connector is disclosed which includes a plurality of leads and a conductive plate. The plate includes a number of bores extending through it. The leads are spaced apart the walls of the bores. A quantum mechanical tunneling material is placed between the leads and the walls of the bores in order to support the leads. This configuration serves to connect the leads to the plate by quantum mechanical tunneling when the voltage between the leads and the plate exceeds a predetermined voltage.
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BACKGROUND OF THE INVENTION
The present invention relates to surgical knives and particularly to knives used in ophthalmic surgery.
For many years, the predominant method of treating a diseased lens is to remove the diseased lens and replace it with an intraocular lens ("IOL"). Two surgical procedures are preferred for removing the diseased lens: extracapsular cataract extraction and phacoemulsification. Extracapsular cataract extraction involves removing the lens in a relatively intact condition by use of a vectus or similar surgical instrument. Phacoemulsification involves contacting the lens with the vibrating cutting tip of an ultrasonically driven surgical handpiece to emulsify the lens, thereby allowing the emulsified lens to be aspirated from the eye. Although extracapsular cataract extraction has been the preferred surgical technique, phacoemulsification has become increasingly popular, in part because the cutting tip of the ultrasonic handpiece requires only a relatively small (approximately 3 millimeter) tunnel incision.
A typical IOL comprises an artificial lens ("optic") and at least one support member ("haptic") for positioning the IOL within the capsular bag. The optic may be formed from any of a number of different materials, including polymethylmethacrylate (PMMA), polycarbonate and acrylics, and it may be hard, relatively flexible or even fully deformable so that the IOL can be rolled or folded prior to insertion. The haptics generally are made from some resilient material, such as polypropylene or PMMA and are generally attached to the optic at the 9 o'clock and 3 o'clock positions. IOL's may be characterized as either "one-piece" or "multi-piece." With one-piece IOL's, the haptic and the optic are formed integrally as a blank and the IOL is then milled or lathed to the desired shape and configuration. The multi-piece IOL's are formed either by attaching the haptic to a pre-formed optic or by molding the optic around the proximal end of the haptic.
The diameter of the optic varies depending on the design of the IOL, but an optic diameter of around 5 millimeters (mm) is most common. Although some IOL's are made from a foldable material, allowing the IOL to be inserted through the typical 3 mm incision used with phacoemulsification, in general, the incision must be enlarged after the aspiration of the cataractous lens to allow the IOL to be implanted. Prior to the present invention, surgeons typically used two separate surgical knives, one with a blade width of approximately 3.2 mm for making the initial incision, and a second knife with a blade width of approximately 5.2 mm for widening the initial incision to permit IOL insertion. While the use of two separate knives works well, it results in added expense and time in purchasing, inventorying and, in the case of reusable knives, sterilizing two different knives.
Accordingly, a need continues to exist for a surgical knife that will precisely cut both the initial small incision needed for the ultrasonic cutting tip and the wider IOL insertion incision used in phacoemulsification.
BRIEF SUMMARY OF THE INVENTION
The present invention improves upon prior art surgical knives by providing a knife with a dual width blade. The first portion of the blade contains a sharp cutting point that, at its widest point, is approximately 3.2 mm wide, the incision width most commonly used with phacoemulsification cutting tips. The blade width then flares gently along a generally arcuate path to approximately 5.2 mm, the incision width preferred by surgeons for small incision, PMMA IOL insertion. The dual widths of the surgical knife of the present invention allow the surgeon to make both required incisions with a single knife, thereby eliminating the use of two separate knives.
Accordingly, one objective of the present invention is to provide a surgical knife capable of making incisions of varying widths.
Another objective of the present invention is to provide a surgical knife capable of making both incision widths typically needed during cataract surgery using phacoemulsification.
Another objective of the present invention is to provide a surgical knife having a scalloped, dual-width blade.
These and other objectives and advantages of the present invention will become apparent from the detailed description, drawings and claims that follow.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a plan view of the surgical knife of the present invention.
FIG. 2 is a cross-sectional view of the intraocular lens illustrated in FIG. 1 taken along line 2--2.
FIG. 3 is an enlarged plan view of the surgical knife of the present invention taken at circle 3 on FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
As can be seen in FIGS. 1, 2 and 3, surgical knife 10 of the present invention includes a blade 12 and a handle 14. Knife 10 may be either reusable or disposable. If knife 10 is to be reusable, blade 12 may be made of any suitable material such as stainless steel or titanium and handle 14 may be made from stainless steel, titanium, or aluminum. If knife 10 is to be disposable, handle 14 also may be made of suitable thermoplastic, fiberglass or composite material. Handle 14 is preferably cylindrical, although other cross-sectional shapes may also be used, and contains knurling 16 or other suitable roughening to make handle 14 more positive to grip.
As can be seen in FIG. 2, blade 12 preferably has a thin cross-section and a sharpened edge 11, is between 17 and 19 mm long, with 18 mm being preferred, and is attached to end 18 of handle 14 by any conventional means. As can best be seen in FIG. 3, cutting end 20 of blade 12 opposite handle end 18 is generally V-shaped from tip 22 to reference points 24 so that the width of cutting end 20 of blade 12 at reference points 24 is approximately between 2.8 and 3.5 mm, with 3.2 mm being preferred. The length of cutting end 20 between tip 22 and reference points 24 is approximately between 3.0 and 4.0 mm, with 3.5 mm being preferred. Between reference points 24 and terminal points 26, cutting end 20 of blade 12 widens along a generally arcuate path to approximately between 3.5 and 5.4 mm, with 5.2 mm being preferred. The use of a scalloped design between reference points 24 and terminal points 26 forces edge 11 to slice across the tissue to be cut rather than pushed against the tissue, allowing for more control and even, smooth cutting. The radius of the arcuate path is approximately between 5.5 mm and 7.5 mm and the length of cutting end 20 of blade 12 between reference points 24 and terminal points 26 is approximately between 2.0 and 3.0 mm, with 2.5 mm being preferred.
In use, the surgeon pushes tip 22 of knife 10 against and pierces the tissue to be cut. The surgeon continues to push tip 22 against the tissue until cutting end 20 is suitably inserted into the tissue up to reference points 24 and removes knife 10. The phacoemulsification of the cataract is performed through this relatively small incision. Once phacoemulsification is complete, the surgeon fully inserts cutting end 20 of knife 10 into the incision, widening the incision to the width of blade 12 at terminal points 26, the widest part of blade 12 and removes knife 10. The IOL (not shown) can now be inserted.
This description is given for purposes of illustration and explanation. It will be obvious to those skilled in the relevant art that modifications may be made to the invention as described herein without departing from its scope or spirit.
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A surgical knife having a handle and a blade with a first generally V-shaped portion for cutting an incision having a first width of approximately 3.2 millimeters and a second generally arcuate portion for widening the incision to a second width of approximately 5.2 millimeters.
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BACKGROUND
Many digital circuits receive a clock signal to operate. One type of circuit that receives a clock signal to operate is a memory circuit, such as a dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), or double data rate synchronous dynamic random access memory (DDR-SDRAM). In a memory circuit operating at high frequencies, it is important to have a clock signal that has about a 50% duty cycle. This provides the memory circuit with approximately an equal amount of time on the high level phase and the low level phase of a clock cycle for transferring data, such as latching rising edge data and latching falling edge data into and out of the memory circuit.
Typically, a clock signal is provided by an oscillator, such as a crystal oscillator, and clock circuitry. The oscillator and clock circuitry often provide a clock signal that does not have a 50% duty cycle. For example, the clock signal may have a 45% duty cycle, where the high level phase is 45% of one clock cycle and the low level phase is the remaining 55% of the clock cycle. To correct or change the duty cycle of the clock signal, a duty cycle detector can indicate the duty cycle of the clock signal and the output of the duty cycle detector can be provided to the clock circuitry that corrects the clock signal to have about a 50% duty cycle.
For these and other reasons there is a need for the present invention.
SUMMARY
One aspect of the present invention provides a duty cycle detector comprising a first circuit configured to receive clock cycles including a first level and a second level. The first circuit is configured to obtain a first value based on the length of the first level and to obtain second and third values based on the length of the second level. The first value is compared to the second and the third values to determine a duty cycle range of the clock cycles.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is block diagram illustrating one embodiment of an electronic system according to the present invention.
FIG. 2 is a block diagram illustrating one embodiment of a duty cycle detector according to the present invention.
FIG. 3 is a diagram illustrating one embodiment of a phase length detector circuit.
FIG. 4 is a diagram illustrating one embodiment of a comparator circuit.
FIG. 5 is a timing diagram illustrating the operation of one embodiment of a duty cycle detector according to the present invention.
DETAILED DESCRIPTION
In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
FIG. 1 is a block diagram illustrating one embodiment of an electronic system 20 according to the present invention. Electronic system 20 includes a host 22 and a memory circuit 24 . Host 22 is electrically coupled to memory circuit 24 via memory communications path 26 . Host 22 can be any suitable electronic host, such as a computer system including a microprocessor or a microcontroller. Memory circuit 24 can be any suitable memory, such as a memory that utilizes a clock signal to operate. In one embodiment, memory circuit 24 comprises a random access memory, such as a dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), or double data rate synchronous dynamic random access memory (DDR-SDRAM).
Memory circuit 24 includes a duty cycle detector 28 that receives a clock signal CLK at 30 and an inverted clock signal bCLK at 32 . Clock signal CLK at 30 is the inverse of inverted clock signal bCLK at 32 . In one embodiment, duty cycle detector 28 receives clock signal CLK at 30 and/or inverted clock signal bCLK at 32 from host 22 via memory communications path 26 . In other embodiments, duty cycle detector 28 receives clock signal CLK at 30 and/or inverted clock signal bCLK at 32 from any suitable device, such as a dedicated clock circuit that is part of memory circuit 24 or situated outside memory circuit 24 .
Duty cycle detector 28 provides two output signals, OUTPUT 1 at 34 and OUTPUT 2 at 36 , to indicate a duty cycle range of clock signal CLK at 30 . Duty cycle detector 28 provides output signals, OUTPUT 1 at 34 and OUTPUT 2 at 36 , to indicate whether the duty cycle of clock signal CLK at 30 is within a duty cycle range, greater than the duty cycle range, or less than the duty cycle range. Duty cycle detector 28 provides the output signals, OUTPUT 1 at 34 and OUTPUT 2 at 36 , to the source of clock signal CLK at 30 and inverted clock signal bCLK at 32 . The source, such as host 22 or a dedicated clock circuit that is part of memory circuit 24 or outside memory circuit 24 , corrects the clock signal CLK at 30 and inverted clock signal bCLK at 32 to have a duty cycle within the duty cycle range. In one embodiment, the duty cycle range is centered around a 50% duty cycle.
FIG. 2 is a block diagram illustrating one embodiment of duty cycle detector 28 according to the present invention. Duty cycle detector 28 includes a phase length detector circuit 52 and a comparator circuit 54 . Phase length detector circuit 52 is electrically coupled to comparator circuit 54 via comparator communications path 56 .
Phase length detector circuit 52 receives clock signal CLK at 58 and inverted clock signal bCLK at 60 and provides three values to comparator circuit 54 via comparator communications path 56 . Clock signal CLK at 58 is the inverse of inverted clock signal bCLK at 60 . One of the three values represents the length of one phase of clock signal CLK at 58 and the other two of the three values represents the other phase of clock signal CLK at 58 .
Comparator circuit 54 receives the three values and compares the one value that represents the length of one phase of clock signal CLK at 58 to each of the other two values. Comparator circuit 54 provides output signals, OUTPUT 1 at 62 and OUTPUT 2 at 64 , to indicate a duty cycle range of clock signal CLK at 58 .
FIG. 3 is a diagram illustrating one embodiment of phase length detector circuit 52 . Phase length detector circuit 52 receives clock signal CLK at 102 and inverted clock signal bCLK at 104 and 106 . Clock signal CLK at 102 is the inverse of inverted clock signal bCLK at 104 and 106 . Phase length detector circuit 52 provides voltage values VA at 108 , VB at 110 , and VC at 112 to a comparator circuit, such as comparator circuit 54 (shown in FIG. 2 ).
Phase length detector circuit 52 includes a first phase length detector 114 , a second phase length detector 116 , and a third phase length detector 118 . First phase length detector 114 receives clock signal CLK at 102 and provides voltage value VA at 108 that represents the length of the high level phase of clock signal CLK at 102 . Second phase length detector 116 receives inverted clock signal bCLK at 104 and provides voltage value VB at 110 that is one representation of the length of the high level phase of inverted clock signal bCLK at 104 , which is the length of the low level phase of clock signal CLK at 102 . Third phase length detector 118 receives inverted clock signal bCLK at 106 and provides voltage value VC at 112 that is another representation of the length of the high level phase of inverted clock signal bCLK at 106 , which is the length of the low level phase of clock signal CLK at 102 . In other embodiments, first phase length detector 114 can receive inverted clock signal bCLK and second and third phase length detectors 116 and 118 can receive clock signal CLK.
First phase length detector 114 includes a first capacitor C 1 at 120 , a first switching transistor 122 , a first bias transistor 124 , a first logic gate 126 , and a first reset transistor 128 . First switching transistor 122 and first bias transistor 124 are n-channel metal oxide semiconductor (NMOS) transistors and first reset transistor 128 is a p-channel metal oxide semiconductor (PMOS) transistor. Also, first logic gate 126 is an AND gate. In other embodiments, first switching transistor 122 , first bias transistor 124 , and first reset transistor 128 can be any suitable type of transistor and first logic gate 126 can be any suitable logic gate.
One side of the drain-source path of first reset transistor 128 is electrically coupled to power VCC at 130 and the other side of the drain-source path of first reset transistor 128 is electrically coupled at 108 to one side of the drain-source path of first switching transistor 122 and one side of first capacitor C 1 at 120 . The other side of the drain-source path of first switching transistor 122 is electrically coupled at 132 to one side of the drain-source path of first bias transistor 124 . The other side of the drain-source path of first bias transistor 124 is electrically coupled to a reference, such as ground, at 134 and the other side of first capacitor C 1 at 120 is electrically coupled to the reference at 134 .
First logic gate 126 receives clock signal CLK at 102 and a gating signal GATE 1 at 136 . The output of first logic gate 126 is electrically coupled at 138 to the gate of first switching transistor 122 . Also, the gate of first reset transistor 128 receives an active low reset signal bRESET at 140 and the gate of first bias transistor 124 receives a bias voltage VBIAS at 142 .
Clock signal CLK at 102 and gating signal GATE 1 at 136 are provided to first logic gate 126 . If gating signal GATE 1 at 136 is at a low logic level, the output of first logic gate 126 is at a low logic level that turns off first switching transistor 122 . With first switching transistor 122 turned off, reset signal bRESET at 140 is provided at a low voltage level to turn on first reset transistor 128 and charge first capacitor C 1 at 120 to a high voltage level. Reset signal bRESET at 140 is switched to a high voltage level to turn off first reset transistor 128 and terminate charging of first capacitor C 1 at 120 . Also, bias voltage VBIAS at 142 is provided to the gate of first bias transistor 124 to bias first bias transistor 124 to conduct current.
Gating signal GATE 1 at 136 is provided at a high logic level for one or more high level phases of clock signal CLK at 102 . With gating signal GATE 1 at 136 at a high logic level, the output of first logic gate 126 follows clock signal CLK at 102 . If clock signal CLK at 102 is at a high logic level, the output of first logic gate 126 is at a high logic level to turn on first switching transistor 122 and current flows through first switching transistor 122 and first bias transistor 124 to the reference at 134 . First capacitor C 1 at 120 discharges with first switching transistor 122 turned on and the voltage value VA at 108 represents the length of the high level phase of clock signal CLK at 102 .
Second phase length detector 116 includes a second capacitor C 2 at 144 , a second switching transistor 146 , a second bias transistor 148 , a second logic gate 150 , and a second reset transistor 152 . Second switching transistor 146 and second bias transistor 148 are NMOS transistors and second reset transistor 152 is a PMOS transistor. Also, second logic gate 150 is an AND gate. In other embodiments, second switching transistor 146 , second bias transistor 148 , and second reset transistor 152 can be any suitable type of transistor and second logic gate 150 can be any suitable logic gate.
One side of the drain-source path of second reset transistor 152 is electrically coupled to power VCC at 130 and the other side of the drain-source path of second reset transistor 152 is electrically coupled at 110 to one side of the drain-source path of second switching transistor 146 and one side of second capacitor C 2 at 144 . The other side of the drain-source path of second switching transistor 146 is electrically coupled at 154 to one side of the drain-source path of second bias transistor 148 . The other side of the drain-source path of second bias transistor 148 is electrically coupled to the reference at 134 and the other side of second capacitor C 2 at 144 is electrically coupled to the reference at 134 .
Second logic gate 150 receives inverted clock signal bCLK at 104 and gating signal GATE 2 at 156 . The output of second logic gate 150 is electrically coupled at 158 to the gate of second switching transistor 146 . Also, the gate of second reset transistor 152 receives active low reset signal bRESET at 140 and the gate of second bias transistor 148 receives bias voltage VBIAS at 142 .
Inverted clock signal bCLK at 104 and gating signal GATE 2 at 156 are provided to second logic gate 150 . If gating signal GATE 2 at 156 is at a low logic level, the output of second logic gate 150 is at a low logic level that turns off second switching transistor 146 . With second switching transistor 146 turned off, reset signal bRESET at 140 is provided at a low voltage level to turn on second reset transistor 152 and charge second capacitor C 2 at 144 to a high voltage level. Reset signal bRESET at 140 is switched to a high voltage level to turn off second reset transistor 152 and terminate charging of second capacitor C 2 at 144 . Also, bias voltage VBIAS at 142 is provided to the gate of second bias transistor 148 to bias second bias transistor 148 to conduct current.
Gating signal GATE 2 at 156 is provided at a high logic level for one or more high level phases of inverted clock signal bCLK at 104 . With gating signal GATE 2 at 156 at a high logic level, the output of second logic gate 150 follows inverted clock signal bCLK at 104 . If inverted clock signal bCLK at 104 is at a high logic level, the output of second logic gate 150 is at a high logic level to turn on second switching transistor 146 . Current flows through second switching transistor 146 and second bias transistor 148 to the reference at 134 . Second capacitor C 2 at 144 discharges with second switching transistor 146 turned on and voltage value VB at 110 represents the length of the high level phase of inverted clock signal bCLK at 104 , which is the low level phase of clock signal CLK at 102 .
Third phase length detector 118 includes a third capacitor C 3 at 160 , a third switching transistor 162 , a third bias transistor 164 , a third logic gate 166 , and a third reset transistor 168 . Third switching transistor 162 and third bias transistor 164 are NMOS transistors and third reset transistor 168 is a PMOS transistor. Also, third logic gate 166 is an AND gate. In other embodiments, third switching transistor 162 , third bias transistor 164 , and third reset transistor 168 can be any suitable type of transistor and third logic gate 166 can be any suitable logic gate.
One side of the drain-source path of third reset transistor 168 is electrically coupled to power VCC at 130 and the other side of the drain-source path of third reset transistor 168 is electrically coupled at 112 to one side of the drain-source path of third switching transistor 162 and one side of third capacitor C 3 at 160 . The other side of the drain-source path of third switching transistor 162 is electrically coupled at 170 to one side of the drain-source path of third bias transistor 164 . The other side of the drain-source path of third bias transistor 164 is electrically coupled to the reference at 134 and the other side of third capacitor C 3 at 160 is electrically coupled to the reference at 134 .
Third logic gate 166 receives inverted clock signal bCLK at 106 and gating signal GATE 2 at 172 . The output of third logic gate 166 is electrically coupled at 174 to the gate of third switching transistor 162 . Also, the gate of third reset transistor 168 receives active low reset signal bRESET at 140 and the gate of third bias transistor 164 receives bias voltage VBIAS at 142 .
Inverted clock signal bCLK at 106 and gating signal GATE 2 at 172 are provided to third logic gate 166 . If gating signal GATE 2 at 172 is at a low logic level, the output of third logic gate 166 is at a low logic level that turns off third switching transistor 162 . With third switching transistor 162 turned off, reset signal bRESET at 140 is provided at a low voltage level to turn on third reset transistor 168 and charge third capacitor C 3 at 160 to a high voltage level. Reset signal bRESET at 140 is switched to a high voltage level to turn off third reset transistor 168 and terminate charging of third capacitor C 3 at 160 . Also, bias voltage VBIAS at 142 is provided to the gate of third bias transistor 164 to bias third bias transistor 164 to conduct current.
Gating signal GATE 2 at 172 is provided at a high logic level for one or more high level phases of inverted clock signal bCLK at 106 . With gating signal GATE 2 at 172 at a high logic level, the output of third logic gate 166 follows inverted clock signal bCLK at 106 . If inverted clock signal bCLK at 106 is at a high logic level, the output of third logic gate 166 is at a high logic level to turn on third switching transistor 162 and current flows through third switching transistor 162 and third bias transistor 164 to the reference at 134 . Third capacitor C 3 at 160 discharges with third switching transistor 162 turned on and the voltage value VC at 112 represents the length of the high level phase of inverted clock signal bCLK at 106 , which is the low level phase of clock signal CLK at 102 .
In phase length detector circuit 52 , each of the capacitors including first capacitor C 1 at 120 , second capacitor C 2 at 144 , and third capacitor C 3 at 160 has a different capacitive value as compared to the other capacitors. First capacitor C 1 at 120 has a capacitive value that is situated midway between the capacitive value of second capacitor C 2 at 144 and the capacitive value of third capacitor C 3 at 160 . First capacitor C 1 at 120 has a capacitive value of CV, second capacitor C 2 at 144 has a capacitive value of CV times (1−X), and third capacitor C 3 at 160 has a capacitive value of CV times (1+X), where X is a percentage of capacitive value CV, such as 4%. Capacitive value CV can be in any suitable capacitive value range, such as the picofarad range or the nanofarad range. In other embodiments, first capacitor C 1 at 120 can have any suitable capacitive value in relation to the capacitive values of second capacitor C 2 at 144 and third capacitor C 3 at 160 .
In operation, phase length detector circuit 52 receives clock signal CLK at 102 and inverted clock signal bCLK at 104 and 106 . Also, phase length detector circuit 52 receives bias voltage VBIAS at 142 to bias each of the bias transistors, including first bias transistor 124 , second bias transistor 148 , and third bias transistor 164 , to the same bias voltage level. Thus, each of the bias transistors is biased to conduct the same amount of current.
The gating signals GATE 1 at 136 and GATE 2 at 156 and 172 are provided at a low logic level to turn off each of the switching transistors, including first switching transistor 122 , second switching transistor 146 , and third switching transistor 162 . With each of the switching transistors turned off, the active low reset signal bRESET at 140 is provided at a low voltage level to turn on the reset transistors, including first reset transistor 128 , second reset transistor 152 , and third reset transistor 168 . With each of the reset transistors turned on, the capacitors, including first capacitor C 1 at 120 , second capacitor C 2 at 144 , and third capacitor C 3 at 160 , are charged to a high voltage level, such as close to VCC. After charging the capacitors, the active low reset signal bRESET at 140 is set to a high voltage level to turn off the reset transistors and terminate charging the capacitors.
Next, gating signal GATE 1 at 136 is provided at a high logic level to gate clock signal CLK at 102 to first switching transistor 122 . Also, gating signal GATE 2 at 156 and 172 is provided at a high logic level to gate inverted clock signal bCLK at 104 and 106 to second switching transistor 146 and third switching transistor 162 . Gating signal GATE 1 at 136 is provided at a high logic level from before a high phase level in clock signal CLK at 102 until after a high phase level in clock signal CLK at 102 . Gating signal GATE 2 at 156 and 172 is provided at a high logic level from before a high phase level in inverted clock signal bCLK at 104 and 106 until after a high phase level in inverted clock signal bCLK at 104 and 106 . Gating signal GATE 1 at 136 and gating signal GATE 2 at 156 and 172 are provided at a high logic level for the same number of high phase levels.
For example, gating signal GATE 1 at 136 is provided at a high logic level for one high phase level of clock signal CLK at 102 . With gating signal GATE 1 at 136 at a high logic level, clock signal CLK at 102 transitions to a high logic level that turns on first switching transistor 122 . With first switching transistor 122 turned on to conduct current, first capacitor 120 discharges through first switching transistor 122 and first bias transistor 124 . As clock signal CLK at 102 transitions to a low logic level, first switching transistor 122 is turned off and first capacitor 120 discontinues discharging. Gating signal GATE 1 at 136 is switched to a low logic level and the resulting voltage value VA at 108 represents the length of the high level phase of clock signal CLK at 102 .
Also, gating signal GATE 2 at 156 and 172 is provided at a high logic level for one high phase level of inverted clock signal bCLK at 104 and 106 . As clock signal CLK at 102 transitions to a low logic level, inverted clock signal bCLK at 104 and 106 transitions to a high logic level that turns on second switching transistor 146 and third switching transistor 162 . With second switching transistor 146 turned on to conduct current, second capacitor 144 discharges through second switching transistor 146 and second bias transistor 148 . With third switching transistor 162 turned on to conduct current, third capacitor 160 discharges through third switching transistor 162 and third bias transistor 164 . As inverted clock signal bCLK at 104 and 106 transitions to a low logic level, second switching transistor 146 and third switching transistor 162 are turned off and second capacitor 144 and third capacitor 160 discontinue discharging. Gating signal GATE 2 is provided at a low logic level and the resulting voltage values VB at 110 and VC at 112 are representations of the length of the high level phase of inverted clock signal bCLK at 104 and 106 , which is the length of the low level phase of clock signal CLK at 102 .
The capacitive value of second capacitor C 2 at 144 is smaller than the capacitive value of third capacitor C 3 at 160 and second capacitor C 2 at 144 discharges faster than third capacitor C 3 at 160 . Thus, the resulting voltage value VB at 110 is less than the resulting voltage value VC at 112 . If the resulting voltage value VA at 108 is between the resulting voltage value VB at 110 and the resulting voltage value VC at 112 , clock signal CLK at 102 has a duty cycle within a predetermined duty cycle range defined by the capacitive values of the capacitors, including first capacitor C 1 at 120 , second capacitor C 2 at 144 , and third capacitor C 3 at 160 . In one embodiment, if the capacitive value of first capacitor C 1 at 120 is capacitive value CV and the capacitive value of second capacitor C 2 at 144 is capacitive value CV minus 4% and the capacitive value of third capacitor C 3 at 160 is capacitive value CV plus 4%, a resulting voltage value VA at 108 between the resulting voltage value VB at 110 and the resulting voltage value VC at 112 indicates a duty cycle in the range of 49% to 51% (or 50% plus or minus 1%). In other embodiments, the relationship between the capacitive values of the capacitors and the duty cycle range can be any suitable relationship.
If the resulting voltage value VA at 108 is less than the resulting voltage value VB at 110 , the high level phase is high for a longer length of time than the low level phase and the duty cycle of clock signal CLK at 102 is greater than the predetermined duty cycle range.
If the resulting voltage value VA at 108 is greater than the resulting voltage value VC at 112 , the high level phase is high for a shorter length of time than the low level phase and the duty cycle of clock signal CLK at 102 is less than the predetermined duty cycle range.
FIG. 4 is a diagram illustrating one embodiment of a comparator circuit 54 . Comparator circuit 54 receives voltage value VA at 202 and 204 , voltage value VB at 206 , and voltage value VC at 208 . Comparator circuit 54 compares voltage value VA at 202 and 204 to voltage value VB at 206 and to voltage value VC at 208 and provides outputs OUTPUT 1 at 210 and OUTPUT 2 at 212 . The outputs indicate the duty cycle range of clock signal CLK, such as clock signal CLK 102 (shown in FIG. 3 ).
Comparator circuit 54 includes a first comparator 214 , a second comparator 216 , an OR gate 218 , and an AND gate 220 . The negative input of first comparator 214 receives voltage value VA at 202 and the positive input of first comparator 214 receives voltage value VB at 206 . The output of first comparator 214 is electrically coupled to one input of OR gate 218 and to one input of AND gate 220 via first output path 222 . Also, first comparator 214 receives an enable signal EVALUATE at 224 that enables first comparator 214 to provide an output on first output path 222 .
The negative input of second comparator 216 receives voltage value VA at 204 and the positive input of second comparator 216 receives voltage value VC at 208 . The output of second comparator 216 is electrically coupled to one input of OR gate 218 and to one input of AND gate 220 via second output path 226 . Also, second comparator 216 receives enable signal EVALUATE at 224 that enables the second comparator 216 to provide an output on second output path 226 .
In operation, voltage value VA at 202 and 204 , voltage value VB at 206 , and voltage value VC at 208 are provided to comparator circuit 54 from a phase length detector circuit, such as phase length detector circuit 52 (shown in FIG. 2 ) and phase length detector circuit 52 of FIG. 3 . Also, first comparator 214 and second comparator 216 receive enable signal EVALUATE at 224 to enable the outputs of first comparator 214 and second comparator 216 .
If voltage value VA at 202 and 204 is greater than voltage value VB at 206 and less than voltage value VC at 208 , the output of first comparator 214 is at a low logic level and the output of second comparator 216 is at a high logic level. In response, the output of OR gate 218 provides a high logic level output signal OUTPUT 1 at 210 and the output of AND gate 220 provides a low logic level output signal OUTPUT 2 at 212 . A high output signal OUTPUT 1 at 210 and a low output signal OUTPUT 2 at 212 indicate voltage value VA at 202 and 204 is between voltage value VB at 206 and voltage value VC at 208 and in the predetermined duty cycle range, such as between 49% and 51%.
If voltage value VA at 202 and 204 is less than voltage value VB at 206 , then voltage value VA at 202 and 204 is also less than voltage value VC at 208 . The output of first comparator 214 is at a high logic level and the output of second comparator 216 is at a high logic level. In response, the output of OR gate 218 provides a high logic level output signal OUTPUT 1 at 210 and the output of AND gate 220 provides a high logic level output signal OUTPUT 2 at 212 . A high output signal OUTPUT 1 at 210 and a high output signal OUTPUT 2 at 212 indicate voltage value VA at 202 and 204 is less than voltage value VB at 206 and voltage value VC at 208 and clock cycle CLK has a duty cycle that is greater than the predetermined duty cycle range, such as greater than 51%.
If voltage value VA at 202 and 204 is greater than voltage value VC at 208 , then voltage value VA at 202 and 204 is also greater than voltage value VB at 206 . The output of first comparator 214 is at a low logic level and the output of second comparator 216 is at a low logic level. In response, the output of OR gate 218 provides a low logic level output signal OUTPUT 1 at 210 and the output of AND gate 220 provides a low logic level output signal OUTPUT 2 at 212 . A low output signal OUTPUT 1 at 210 and a low output signal OUTPUT 2 at 212 indicate voltage value VA at 202 and 204 is greater than voltage value VB at 206 and voltage value VC at 208 and clock cycle CLK has a duty cycle that is less than the predetermined duty cycle range, such as less than 49%.
FIG. 5 is a timing diagram illustrating the operation of one embodiment of a duty cycle detector according to the present invention. The duty cycle detector is similar to duty cycle detector 28 of FIG. 2 . The duty cycle detector includes a phase length detector circuit, such as phase length detector circuit 52 of FIG. 3 , and a comparator circuit, such as comparator circuit 54 of FIG. 4 .
The phase length detector circuit receives clock signal CLK at 300 and inverted clock signal bCLK at 302 , which is the inverse of clock signal CLK at 300 . Also, the phase length detector circuit receives gating signals GATE 1 at 304 and GATE 2 at 306 and the active low reset signal bRESET at 308 . In addition, the phase length detector circuit receives a bias voltage (not shown), such as bias voltage VBIAS (shown in FIG. 3 ), to bias the bias transistors 124 , 148 , and 164 to conduct current.
The phase length detector provides voltage values at 310 , including voltage value VA at 312 , voltage value VB at 314 , and voltage value VC at 316 to the comparator circuit. An enable signal EVALUATE at 318 is received by the comparator circuit to enable outputs from the comparators. The comparator circuit provides output signals OUTPUT 1 at 320 and OUTPUT 2 at 322 .
To begin, gating signals GATE 1 at 304 and GATE 2 at 306 are provided at a low logic level at 324 to turn off switching transistors 122 , 146 , and 162 . The reset signal bRESET at 308 is at a low logic level at 326 to turn on reset transistors 128 , 152 , and 168 and charge capacitors 120 , 144 , and 160 to high voltage levels, indicated at 328 . To obtain a duty cycle range, reset signal bRESET at 308 is switched to a high voltage level at 330 to turn off reset transistors 128 , 152 , and 168 and discontinue charging capacitors 120 , 144 , and 160 .
Gating signal GATE 1 at 304 transitions to a high logic level at 332 , while clock signal CLK at 300 is at a low level. At 334 , clock signal CLK at 300 switches to a high level that turns on first switching transistor 122 and begins to discharge first capacitor 120 . Voltage value VA at 312 drops at 336 as first capacitor 120 discharges. At 338 , clock signal CLK at 300 switches to a low level that turns off first switching transistor 122 and discontinues discharging first capacitor 120 . At 340 , gating signal GATE 1 at 304 switches to a low logic level and at 342 the resulting voltage value VA at 312 on first capacitor 120 represents the length of the high level phase of clock signal CLK at 300 .
Gating signal GATE 2 at 306 transitions to a high logic level at 344 , while inverted clock signal bCLK at 302 is at a low level. At 346 , inverted clock signal bCLK at 302 transitions to a high level, which turns on second switching transistor 146 and third switching transistor 162 . With second switching transistor 146 and third switching transistor 162 turned on, second capacitor 144 and third capacitor 160 begin to discharge. At 348 , since the capacitive value of second capacitor 144 is smaller than the capacitive value of third capacitor 160 , voltage value VB at 314 discharges faster than voltage value VC at 316 . At 350 , inverted clock signal bCLK at 302 transitions to a low level that turns off second switching transistor 146 and third switching transistor 162 . Turning off second switching transistor 146 and third switching transistor 162 discontinues discharging second capacitor 144 and third capacitor 160 . At 352 , gating signal GATE 2 at 306 switches to a low logic level. At 354 , the resulting voltage value VB at 314 on second capacitor 144 is one representation of the length of the high level phase of inverted clock signal bCLK at 302 , which is the length of the low level phase of clock signal CLK at 300 . At 356 , the resulting voltage value VC at 316 on third capacitor 160 is another representation of the length of the high level phase of inverted clock signal bCLK at 302 , which is the length of the low level phase of clock signal CLK at 300 .
At 358 , enable signal EVALUATE at 318 transitions to a high voltage level to enable first comparator 214 and second comparator 216 . Output signal OUTPUT 1 at 320 and output signal OUTPUT 2 at 322 become valid at 360 . With voltage value VA at 312 between voltage value VB at 314 and voltage value VC at 316 , output signal OUTPUT 1 at 320 is at a high logic level at 362 and output signal OUTPUT 2 at 322 is at a low logic level at 364 . Enable signal EVALUATE at 318 transitions to a low voltage level at 366 to tri-state first comparator 214 and second comparator 216 . Output signal OUTPUT 1 at 320 and output signal OUTPUT 2 at 322 become invalid at 368 . Reset signal bRESET at 308 transitions to a low level at 370 that charges capacitors 120 , 144 , and 160 and voltage values, voltage value VA at 312 , voltage value VB at 314 , and voltage value VC at 316 , to high voltage levels at 372 .
The duty cycle detector provides the output signals, OUTPUT 1 at 320 and OUTPUT 2 at 322 , to the source of clock signal CLK at 300 and inverted clock signal bCLK at 302 . The source receives the valid output signals, OUTPUT 1 at 320 and OUTPUT 2 at 322 , between 360 and 368 . If the valid output signals, OUTPUT 1 at 320 and OUTPUT 2 at 322 , indicate the duty cycle of clock signal CLK at 300 is not within the duty cycle range, the source corrects the clock signal CLK at 300 and inverted clock signal bCLK at 302 to have a duty cycle closer to and eventually within the duty cycle range.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.
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A duty cycle detector comprising a first circuit configured to receive clock cycles including a first level and a second level. The first circuit is configured to obtain a first value based on the length of the first level and to obtain second and third values based on the length of the second level. The first value is compared to the second and the third values to determine a duty cycle range of the clock cycles.
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FIELD OF THE INVENTION
[0001] The present invention relates to an antitumor formulation based on paclitaxel and albumin nanoparticles able to give injectable reconstituted aqueous mixtures having high inalterability with time.
BACKGROUND OF THE INVENTION
[0002] Paclitaxel is a natural substance well known in literature, with important antitumor activity. Its poor water solubility makes it difficult to administer to man, for which reason various systems have been developed to render it injectable.
[0003] Bristol Myers Squibb (BMS) have conceived and patented a composition, known by the name of TAXOL®, in which the paclitaxel is emulsified with cremophor which induces various side effects in the patient (Lorenz et al., Agents Action 7, 63-67 (1987); Weiss et al., J. Clin. Oncol. 8, 1263 (1990)). The BMS formulation also involves lengthy administration times due to the dilution of the active principle.
[0004] To obviate the described drawbacks, BMS have patented (EP-A-0584001, EP-A-0783885, EP-A-0783886, U.S. Pat. No. 5,641,803, U.S. Pat. No. 5,670,537) formulations of TAXOL® with the same dose of paclitaxel but with other excipients able to prevent strong anaphylactic reactions. However in all cases patient administration must be effected very slowly, over a period of about 3 hours.
[0005] To prevent the side effects of TAXOL®, the cremophor was replaced with human serum albumin (HSA) in view of its biocompatibility and its considerable capacity to bind to the paclitaxel (Kumar et al., Res. Comm. in Chem. Path. and Pharm., 80 (3), 337-343 (1993); Paal et al., Eur. J. Biochem. 268, 2187-2191 (2001)). The property of HSA to form microspheres containing active principles dissolved in organic solvents insoluble in water (Kramer et al., J. Pharm. Sci. 63, 1646-1647 (1974); Grinstaff and Suslick, J. Am. Chem. Soc. 112, 7807-7809 (1990); Grinstaff and Suslick, Polym. Prepr. 32, 255-256 (1991)) has also enabled the development of systems for administering paclitaxel in higher concentrations than with TAXOL®.
[0006] Injectable nanoemulsions of paclitaxel and HSA can be obtained by known ultrasonication, high pressure homogenization and microfluidization techniques (Alleman et al., Eur. J. Pharm. Biopharm. 39 (5), 173-191 (1993)).
[0007] On the basis of these elements and by using the aforestated ultrasonication and high pressure homogenization techniques, the American company VivoRx Pharmaceuticals Inc. has developed the formulation CAPXOL (R) containing paclitaxel and HSA.
[0008] In U.S. Pat. No. 5,439,686, U.S. Pat. No. 5,498,421, U.S. Pat. No. 5,560,933 and the corresponding WO 94/18954, VivoRx claims microparticles of paclitaxel and HSA prepared using ultrasonication techniques, to give particles of mean size (MPS) <10 microns. The preparation methods described in these patents cannot be used on an industrial scale, and moreover the microparticles thus obtained have too high an MPS, which makes them unsuitable and unusable for administration to patients.
[0009] This was well known to the said VivoRx, which then in U.S. Pat. No. 5,916,596 and U.S. Pat. No. 6,096,331 and in WO 98/14174 and WO 99/00113 described and claimed sterile nanoemulsions of paclitaxel and HSA obtained by reconstituting with sterile aqueous 0.9% NaCl solution lyophilized powders with MPS<0.2 microns. These nanoemulsions, which are obtained using high pressure homogenization, as described in the cited patents, are stated to have high stability, where the term “stability” means that the MPS is constant with time and that nanoparticle precipitation is absent (U.S. Pat. No. 6,096,331, Ex. 11).
[0010] Using maximum care, the present applicants have several times reproduced the examples of the aforestated patents, in particular Examples 1, 5 and 6 of U.S. Pat. No. 5,916,596, without ever obtaining the result specified in the examples and claimed in the patent. Having prepared the mixtures as described, then processing them with an Avestin homogenizer within the pressure range recommended in U.S. Pat. No. 5,916,596, nanoemulsions at pH=6.7 were obtained which, when evaporated in a rotavapor as reported in the said patent, always provided nanoemulsions with MPS of about 0.2 microns (increase of MPS>0.02 microns after evaporation) which are poorly stable in their formulations in injectable physiological solutions (increase in MPS of about 0.05 microns and tendency to sediment in about 12 hours) and difficult to filter through 0.22 microns filters for their sterilization, in contrast to that stated in the said patent.
[0011] The present applicants have made the most careful attempts to effect filtration with the membranes described in U.S. Pat. No. 5,916,596, but these attempts have always failed, with clogging of the filters and paclitaxel yields always <30%, in contrast to the 70-100% declared. Moreover the stability (evaluated in accordance with the teachings of Example 11 of U.S. Pat. No. 6,096,331) of the products prepared by the method just described, then lyophilized and reconstituted as reported in U.S. Pat. No. 5,916,596 and U.S. Pat. No. 6,096,331 has never reached 24 hours (hence much less than the 72 hours declared in the patents).
SUMMARY OF THE INVENTION
[0012] The main object of the present invention is therefore to provide an antitumor formulation consisting of nanoparticles of paclitaxel and human serum albumin, which with a physiological solution enables injectable reconstituted mixtures to be formed in which said particles have a stability (in the aforestated sense) considerably greater than that possible in the known art, and specifically a stability exceeding 24 hours.
[0013] This and further objects are attained by a formulation consisting of a lyophilized powder of nanoparticles of paclitaxel and human serum albumin, in which the paclitaxel is present in a quantitity between 1% and 20% and the albumin between 60% and 98%, the percentages being by weight and the mean nanoparticle size being less than 0.2 microns, wherein said lyophilized powder contains between 1% and 20% by weight of biocompatible salts obtained by salification of at least one biocompatible acid or due to the presence of at least one biocompatible acid buffer substance, the acid or the buffer substance being present in a quantity such that the pH of a reconstituted aqueous injectable mixture of the powder is between 5.4 and 5.8.
[0014] The presence of the salts is due to the fact that an acid buffer substance is (as chemists well know) formed by an acid and a salt thereof and that some basic groups present in albumin are salified by the acids, therefore providing a mixture having a pH lower than a typical pH of albumin, i.e. 6.79-6.89 according to Merck Index, 13 th Ed. page 1519.
[0015] Experiments have shown that if use is made of an acid buffer substance (such as a mixture of citric acid and sodium citrate), the results are not so good as with the use of the acid alone (citric acid or other biocompatible acid), as far as the abovementioned stability is concerned.
[0016] Obviously, the pH of the lyophilized powder can be easily measured after water has been added to form an aqueous mixture with it. The acidic nanoparticles have been studied showing that also water is present therein: the amount of water in the powder is up to 5% (w/w), usually about 2% to 4.5% (w/w). As a consequence, even the above mentioned nanoparticles containing water form part of the present invention.
[0017] The invention also relates to injectable reconstituted aqueous mixtures of such formulations, in which the paclitaxel is present at a concentration between 0.1 and 3 mg/ml, preferably between 0.5 and 2.5 mg/ml.
[0018] The formulations of the invention may be obtained by mixing a sterile aqueous solution of human serum albumin (HSA) with a sterile solution of paclitaxel and treating this mixture in accordance with the teachings of the aforesaid Vivorx patents, but differing from such teachings in the fact that to the aqueous HSA solution, before it is mixed with paclitaxel, at least one biocompatible acid or acid buffer substance is added in a quantity sufficient to bring the pH of the solution to between 5.4 and 5.8, preferably between 5.5 and 5.7.
[0019] The biocompatible acids may be chosen from the group consisting of HCl, citric acid, phosphoric acid, acetic acid, biocompatible organic and inorganic acids.
[0020] The same formulations may be obtained also by a process according to which an aqueous mixture containing paclitaxel and albumin at a temperature between 0° C. and 40° C. is subjected to homogenization treatment at high pressure between 9000 and 40000 psi, to give a nanoemulsion which is frozen between −20° C. and −80° C. and is finally lyophilized by heating at a temperature between +20° C. and +35° C., wherein said aqueous mixture is obtained under sterile conditions by dissolving said albumin in sterile water to a concentration between 2% and 3% (w/v), then adding to said albumin solution between 2% and 4% (v/v) of chloroform and then paclitaxel in sterile powder form in a quantity between 5.40% and 15.0%, preferably between 5.60% and 13.7%, by weight on the weight of the albumin present in the solution, at least one biocompatible acid or acid buffer substance being added to said albumin solution before adding the paclitaxel in a quantity sufficient to bring the pH of the mixture to between 5.4 and 5.8, preferably between 5.5 and 5.7.
[0021] It may be noted that the use of paclitaxel in sterile powder form in the latter process not only greatly simplifies the plant itself and the process compared with the known art and enables the time required to complete the mixing of the various components before the homogenization treatment to be considerably shortened, but also enables better final yields to be obtained and simplifies the conditions to be observed in order to obtain the desired sterile lyophilized powders.
[0022] The results obtained with the use of the formulations according to the present invention are totally unexpected and surprising, because they are in contrast to the teachings of the art which provides for the use of HSA solutions of pH values resulting from the dilution of injectable solutions of said albumin complying with FDA specifications, hence at pH=6.9±0.5 (see Examples 1, 5 and 6 of U.S. Pat. No. 5,916,596). In contrast to the teachings of the known art, it has been discovered that at pH values between 5.4 and 5.8 a stability of greater than 24 hours can be obtained for the reconstituted lyophilized products.
DETAILED DESCRIPTION OF THE INVENTION
[0023] To clarify the understanding of the characteristics of the present invention, some non-limiting examples of its implementation will now be described.
EXAMPLE 1
[0024] Preparation of a formulation with HCl and paclitaxel dissolved in cloroform An injectable aqueous 25% (w/v) HSA solution in accordance with FDA specifications (pH=6.9+0.5) is diluted to 3% (w/v) with sterile demineralized water, the pH being corrected to 5.6 with 1M HCl which salifies some basic groups present in albumin. 40 ml of said solution, previously sterilized, are mixed with 1.2 ml of a sterile solution of paclitaxel (59.0 mg/ml) in CHCl 3 , after which the mixture is processed in a homogenizer (suitably sterilized) at high pressure (9000-40000 psi) until a nanoemulsion (MPS<0.2 microns) is obtained, this being frozen to −25° C. and lyophilized for 60 hours under sterile conditions, while raising the temperature to +20° C.
[0025] The powder obtained, containing 4.25% (w/w) of paclitaxel and 3.6 (w/w) of water, is reconstituted with an aqueous 0.9% NaCl solution to a paclitaxel concentration of 2 mg/ml. The formulation obtained has an MPS of 0.16 microns, pH=5.6, and a stability >24 hours.
[0026] Equivalent results were obtained by using phosphoric acid instead of HCl.
EXAMPLE 2
[0027] Preparation of a Formulation With Citric Acid and Paclitaxel Dissolved in Cloroform
[0028] An injectable aqueous 25% (w/v) HSA solution in accordance with FDA specifications (pH=6.9±0.5) is diluted to 2.5% (w/v) with sterile demineralized water, the pH being corrected to 5.5 with sterile citric acid which salifies some basic groups present in albumin. 60 ml of said solution are mixed with 1.7 ml of a sterile solution of 60.0 mg/ml of paclitaxel in CHCl 3 , after which the mixture is processed in a homogenizer (suitably sterilized) at high pressure (9000-40000 psi) until a nanoemulsion (MPS<0.2 microns) is obtained, this being rapidly frozen to −40° C. and lyophilized for 55 hours under sterile conditions, while raising the temperature to +35° C.
[0029] The powder obtained, containing 5.2% of paclitaxel and 4.9% (w/w) of water, is reconstituted with an aqueous 0.9% NaCl solution to a paclitaxel concentration of 2 mg/ml. The formulation obtained has an MPS of 0.17 microns, pH=5.5, and a stability >24 hours.
EXAMPLE 3
[0030] Preparation of a formulation with HCl and paclitaxel dissolved in cloroform An injectable aqueous 25% HSA solution in accordance with FDA specifications is diluted to 3% (w/v) with sterile demineralized water, the pH being corrected to 5.6 with 1M HCl which salifies some basic groups present in albumin. 60 ml of said solution, suitably sterilized, are mixed with 1 . 5 ml of a sterile solution of 75 mg/ml of paclitaxel in CHCl 3 , after which the mixture is processed in a homogenizer (suitably sterilized) at high pressure (9000-40000 psi) until a nanoemulsion (MPS<0.2 microns) is obtained, this being frozen to −50° C. and lyophilized for 50 hours under sterile conditions, while raising the temperature to +30° C.
[0031] The powder obtained, containing 4.41% of paclitaxel and 3.8% (w/w) of water, is reconstituted with an aqueous 0.9% NaCl solution to a paclitaxel concentration of 2.5 mg/ml. The formulation obtained has an MPS of 0.175 microns, pH=5.6, and a stability >24 hours.
[0032] By repeating the same procedure but without adding HCl and hence working at about pH 6.5, a formulation is obtained with an MPS of 0.24 microns and a stability of about 10 hours.
EXAMPLE 4
[0033] Preparation of a Formulation With Citric Acid From a Paclitaxel Solution
[0034] An injectable aqueous 25% (w/v) HSA solution in accordance with FDA specifications is diluted to 3% (w/v) with sterile demineralized water, the pH being corrected to 5.4 with sterile citric acid which salifies some basic groups present in albumin.
[0035] 50 ml of said solution are mixed under vigorous agitation for at least 40 minutes with 1.25 ml of a sterile solution of paclitaxel in chloroform (75 mg/ml).
[0036] The mixture is processed in a homogenizer (suitably sterilized) at high pressure (9000-40000 psi) until a nanoemulsion (MPS<0.2 microns) is obtained, this being rapidly frozen to −30° C. and lyophilized for 57 hours under sterile conditions, while raising the temperature to +35° C.
[0037] The powder obtained, containing 5.00% (w/w) of paclitaxel and 4.3 (w/w) of water, is reconstituted with an aqueous 0.9% NaCl solution to a paclitaxel concentration of 2 mg/ml. The formulation obtained has an MPS of 0.19 microns, pH=5.4, and a stability >24 hours.
[0038] Equivalent results are obtained by using acetic acid instead of citric acid.
EXAMPLE 5
[0039] Preparation of a Formulation With HCl and Paclitaxel in Powder Form
[0040] An injectable aqueous 25% (w/v) HSA solution in accordance with FDA specifications (pH=6.9±0.5) is diluted to 3% (w/v) with sterile demineralized water, the pH being corrected to a value of 5.6 with 1M HCl which salifies some basic groups present in albumin.
[0041] 57 ml of said solution, previously sterilized, are mixed under vigorous stirring for at least 30 minutes, with 1.40 ml of sterile chloroform and with 108 mg of sterile paclitaxel (titre >99%) in powder form.
[0042] The mixture is processed in a homogenizer (suitably sterilized) at high pressure (9000-40000 psi) until a nanoemulsion (MPS<0.2 microns) is obtained, this being rapidly frozen to −80° C. and lyophilized for 55 hours under sterile conditions, while raising the temperature to +30° C.
[0043] The powder obtained, containing 4.83% (w/w) of paclitaxel and 4% (w/w) of water, is reconstituted with an aqueous 0.9% NaCl solution to a paclitaxel concentration of 2 mg/ml. The formulation obtained has an MPS of 0.175 microns, pH=5.6, and a stability >24 hours.
[0044] Equivalent results are obtained by using phosphoric acid instead of hydrochloric acid.
[0045] It is important to remark that the use of sterile paclitaxel in powder form enables to achieve the important advantage that only one reactor is required for forming the liquid mixture containing HSA and paclitaxel with consequent reduction of costs and time necessary for completing the process.
EXAMPLE 6
[0046] Preparation of a Formulation With Citric Acid and Paclitaxel in Powder Form
[0047] An injectable aqueous 25% (w/v) HSA solution in accordance with FDA specifications is diluted to 3% (w/v) with sterile demineralized water, the pH being corrected to a value of 5.4 with citric acid which salifies some basic groups present in albumin.
[0048] 50 ml of said solution, previously sterilized, are mixed under vigorous stirring for at least 40 minutes, with 1.23 ml of sterile chloroform and with 98 mg of sterile paclitaxel (titre >99%) in powder form.
[0049] The mixture is processed in a homogenizer (suitably sterilized) at high pressure (9000-40000 psi) until a nanoemulsion (MPS<0.2 microns) is obtained, this being rapidly frozen to −30° C. and lyophilized for 57 hours under sterile conditions, while raising the temperature to +35° C.
[0050] The powder obtained, containing 4.80% (w/w) of paclitaxel and 3.8% (w/w) of water, is reconstituted with an aqueous 0.9% NaCl solution to a paclitaxel concentration of 2 mg/ml. The formulation obtained has an MPS of 0.19 microns, pH=5.4, and a stability >24 hours.
[0051] Equivalent results are obtained by using acetic acid instead of citric acid.
EXAMPLE 7
[0052] Preparation of a Formulation With Sterile Citric Acid and Paclitaxel in Powder Form.
[0053] An injectable aqueous 25% (w/v) HSA solution in accordance with FDA specifications is diluted to 3% (w/v) with sterile demineralized water, the pH being corrected to a value of 5.5 with sterile citric acid which salifies some basic groups present in albumin.
[0054] 37 ml of said solution are mixed under vigorous stirring for at least 40 minutes, with 0.91 ml of sterile chloroform and 71 mg of sterile paclitaxel (titre >99%) in powder form, after which the mixture is cooled to 5-8° C.
[0055] The mixture is processed in a homogenizer (suitably sterilized) at high pressure (9000-40000 psi) until a nanoemulsion (MPS<0.2 microns) is obtained, this being rapidly frozen to −80° C. and lyophilized for 58 hours under sterile conditions, while raising the temperature to +30° C.
[0056] The powder obtained, containing 4.70% (w/w) of paclitaxel and 4.5% (w/w) of water, is reconstituted with an aqueous 0.9% NaCl solution to a paclitaxel concentration of 2 mg/ml. The formulation obtained has an MPS of 0.185 microns, pH=5.5, and a stability >24 hours.
EXAMPLE 8
[0057] Preparation of a Formulation Containing 9.36% of Paclitaxel
[0058] An injectable aqueous 25% HSA solution in accordance with FDA specifications is diluted to 3% (w/v) with sterile demineralized water, the pH being corrected to 5.6 with 1M HCl which salifies some basic groups present in albumin. 60 ml of said solution, suitably sterilized, are mixed with 2.15 ml of a sterile solution of 110 mg/ml of paclitaxel in CHCl 3 , after which the mixture is processed in a homogenizer (suitably sterilized) at high pressure (9000-40000 psi) until a nanoemulsion (MPS<0.2 microns) is obtained, this being frozen to −50° C. and lyophilized for 50 hours under sterile conditions, while raising the temperature to +30° C.
[0059] The powder obtained, containing 9.36% of paclitaxel and 3.9% (w/w) of water, is reconstituted with an aqueous 0.9% NaCl solution to a paclitaxel concentration of 2.5 mg/ml. The formulation obtained has an MPS of 0.175 microns, pH=5.6, and a stability >24 hours.
EXAMPLE 9
[0060] Preparation of Formulation at pH 5.5
[0061] An injectable aqueous 20% (w/v) HSA solution in accordance with FDA specifications (pH=6.9±0.5) is diluted to 3% (w/v) with sterile demineralized water, the pH being corrected to a value of 5.5 with citric acid which salifies some basic groups present in albumin.
[0062] 110 ml of said solution are mixed with 4.10 ml of sterile CHCl 3 and with 639 mg of sterile paclitaxel (titre >99%) in powder form, then the mixture is processed in a high pressure homogenizer (suitably sterilized) until a nanoemulsion (MPS about 0.2 microns) is obtained, this being filtered through a sterile filter (0.2 microns), evaporated under vacuum to remove the solvents, frozen and lyophilized under sterile conditions for 48 hours.
[0063] The powder obtained, containing 10.8% (w/w) of paclitaxel, is reconstituted with an aqueous 0.9% NaCl solution to a paclitaxel concentration of 2 mg/ml. The formulation obtained has an MPS of 0.15 microns and a stability >24 hours.
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Antitumor formulation based on nanoparticles of paclitaxel and human serum albumin as obtained by the addition of a biocompatible acid to an aqueous albumin solution before this is mixed with paclitaxel during the nanoparticle production process, the injectable solutions of this formulation having a pH between 5.4 and 5.8 and having stability and inalterability with time.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of International Patent Application No. PCT/CN2010/000765 with an international filing date of May 28, 2010, designating the United States, now pending. The contents of the aforementioned application, including any intervening amendments thereto, are incorporated herein by reference.
CORRESPONDENCE ADDRESS
[0002] Inquiries from the public to applicants or assignees concerning this document should be directed to: MATTHIAS SCHOLL P.C., ATTN.: DR. MATTHIAS SCHOLL ESQ., 14781 MEMORIAL DRIVE, SUITE 1319, HOUSTON, TX 77079.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The invention relates to a method and device for automatically monitoring the production of fluid film.
[0005] 2. Description of the Related Art
[0006] To determine the accuracy of fluid film thickness is a common issue of many industries, for example, the glue film thickness of the adhesive pasting production, the grinding film thickness of the food processing industry and the color pigment production, and so on. For even grinding and steady dispensing of flour mixture in the food processing industry, if inappropriate amount of flour mixture is dispensed in the oven, under the fixed speed and steady temperature processing condition, pre-mature cooking or overcooking may occur, and it can also cause fire in the extreme situation. For the substrate pasting production, the correct amount of adhesive application is also an important issue. In normal pasting process, the operator can only execute the quality control inspection from the final product and determine whether the quality is satisfied. In any case of quality problems, such a production batch has already failed to meet standard quality and becomes the uncontrollable wastage.
[0007] In the printing industry, the evenness of color film thickness is an important issue to determine the production quality. The determination of the accurate and appropriate printing ink value is a hot topic in the printing industry. Nowadays, color adjustment solely relies on the operator's subjective judgment. Traditional color adjustment is based on the worker's skill. The trial method is employed to achieve the color balance condition. Each color station of a printing machine is equipped with many inking control zones, and a machine operator spends a lot of time to adjust the inking values, which can lead to a great delay of color correction and cause imbalance printing results. In daily life, the stamp surface of a traditional rubber stamp needs to pick up ink film from an ink pad, and stamps onto the paper. If the ink pad lacks of ink, for example, the stamp surface has carried thin thickness of ink film, the printing image will become light, and vice versa, the ink pad with excessive ink will have the too dark stamping. For the case of the imbalance of inking level condition between the ink pad surface, the stamping image will be imbalance and results in stamping failure. Hence, trial methodology has to be applied before every time of stamping. First of all, it has to find out whether the ink pad has sufficient ink, and then proceed of stamping until satisfaction before actual stamping production begins. This is a typical problem which needs to be fixed in the printing industry and the trial methodology is commonly used.
[0008] In traditional printing technology, color correction process has to collect the printing information from the printed sheet, and an operator has to use a visual or reading device to scan the traditional color bar to monitor and amend the color value. No matter which method is applied, manually or automatically correcting the color zones needs analysis from the finished product. As a result, the color correction respond time is delayed. During the high speed and large volume production process, the delay of color correction responding time can cause a large amount of defect products. Because of the above reason, the industry needs a direct and pro-active color controlling system to replace the indirect density retrieving method from the conventional color bar.
[0009] All industries quality control system needs to retrieve production data for amendment. The work flow of data collection is described as follows: the selection of data reading device; the analyzer installation location; the timing of collecting the production data, and so on. These can clearly distinguish the major different between this invention and the conventional data reading method.
[0010] By comparing this invention with the conventional method: This invention technology is overrided the traditional method, the major different of monitoring the fluid dispensing value hardware is installed at the up stream of the production work flow, the reading device has already begun to monitor the metering system and analyzing the material dispensing value before the actual product being made; this system will be repeatedly to compare the dispensing value accuracy with the pre-determined reference setting, it will be in a real time bases to conduct the closed loop adjustment if it is out of range condition, it will amend the fluid thickness continuously and maintain the product quality within tolerance, meanwhile it continues to feed onto the substrate for production and the goal is to deliver the product at the best quality perfect result, hence this is a pro-active and creative quality control technology. In order to have the conventional method of the closed loop fluid thickness control to keep within the tolerance, the amendment data must be collected from the quality control media tool which measures the finished product, the data reading device has to be installed at the down stream of the production work flow, the actual installation position must be at the products discharge location for the fluid thickness inspection from the immediate finished products, which is used to verify the applied material whether it is acceptable or needs to be adjusted. Because of the inspection system can only inspect from the finished products, such inspection position will not be possible nor simultaneously to inspect the dispensing value at the up stream location of fluid metering system for controlling the material dispensing value: for the time being, the production line continues to apply the material dispensing value which has been set prior to the inspection, therefore the defect gets worse as the excessive material are still dispensing until the new dispensing value generates from inspection completion, a passive way of quality control technology.
[0011] This invention is a pro-active inspection method, which is different with the passive type of operation. The pro-active method is repeatedly control in production, which is a creative up stream technology. It is a totally vise-verse technology by comparing with conventional passive way technology which inspects the finished products at the downstream location.
[0012] The fluid application industry does not record any pro-active way inspection technology at the up stream work flow so far, therefore this invention is the innovative way to adopt the pro-active technology background; creatively changes the conventional passive quality inspection mode from the downstream end product data collection to the up stream position to become a new technology which has a pro-active mode of controlling.
[0013] Regardless the described passive way or pro-active way, the data collecting condition can be retrieved from flat or rotating surface; both reading conditions will not affect this invention data retrieving work flow and location setting.
SUMMARY OF THE INVENTION
[0014] This invention can solve the technical problem such as, how to provide a method and device which can initiatively, proactively, accurately, appropriately pre-determine and monitor the production of the fluid films at the upstream process. In printing process, applying this initiative and proactive monitor method to accurately adjust the color value against the pre-determined color zone inking value, and achieve the ultimate inking value before production will reduce the unnecessary adjustment time and material wastage and maintain the products in the highest quality level.
[0015] This invention provides an initiative and pro-active intelligent controlling method for fluid films in the material metering process, based on measuring the fluid film thickness to automatically control the material metering production system.
[0016] The invention provides an initiative, pro-active, intelligent monitoring method for fluid films, comprising:
activating a dispenser to deliver appropriate material from a storage duct to a metering system for even distribution of a fluid film; allowing the fluid film to pass a sample retrieving roller; measuring the fluid film on the sample retrieving roller using a data reading device to obtain film thickness data; transmitting the data to an analyzer to examine the data against a predetermined reference value; transmitting a comparison result in real time by the analyzer to a production equipment controlling console; controlling the storage duct to dispense material through the material metering system and adjusting the film thickness; repeating the above steps to make a film thickness within the reference range; and maintaining the thickness at the narrowest tolerance deviation, and continuously delivering onto a substrate for production.
[0025] Printing ink is also a kind of fluid type material. Color pigment becomes a printing ink film after passing through the metering system. The thickness of the printing ink film is measurable. Such an ink film is a color measuring media. The retrieved ink film data can analyze the color value after such material being measured.
[0026] In a class of this embodiment, the fluid film is a printing ink film.
[0027] The method of the invention can be used to maintain an even ink film color value, to cover up the printing plate surface by accurately adjusting the ink zones.
[0028] Each ink zone requires sufficient storage of printing ink, from the material storage duct and the metering system to the printing plate surface, to cover up the printing area, and finally transfers onto the substrate surface for production. For different printing area and each ink zone, different amount of inking value is required. A good printing product needs an even and consistence supply of ink and metering system in order to provide an appropriate inking distribution. The ultimate goal is to accurately maintain and continuously amend the inking system operation without using the finished printing product as the inking value correction aim.
[0029] This invention provides an initiative and proactive method, comprising pre-examining the fluid type film thickness, determining the even metering volume, continuously monitoring and maintaining the film thickness within tolerance range, then transferring to the application system for production. The result of each finished product shall be the best and uniform quality as well as at the minimum deviation tolerance level, the high accuracy of the finished products prediction at the best quality result.
[0030] In a class of this embodiment, the pre-set fluid film reference target adopts a neutral grey balance technology. Pre-determined black “K” neutral black color value functions as the reference blue print for the neutral grey formation inking units which are the composition of the primary and subsequent color group as reference aim. The analyzer uses the pre-determined black “K” value to compute each related production color unit in appropriate matching condition by determining the desire ink film thickness, proceeds with even metering, amends the ink film when necessary to the uniform condition, continuously transfers to the substrate for production.
[0031] This invention can adopt the neutral grey balance technology disclosed International Patent Application Nos. PCT/CN2008/001021 and PCT/CN2009/001490. Based on the neutral grey balance theory, the primary color is the commonly used material for the color printing production, e.g. cyan shaded as blue, magenta shaded as red and yellow. Combining the three primary color in different values forms the color picture. In theory, equal portion of the primary color mixed with each other will form a dark black color called “neutral black”. The “neutral grey” is the result of the equal portion of pre-determined percentage of halftone. Further combination of a primary color and a secondary color such as a primary color with its opponent color can also form the “neutral grey” which comprises cyan+red, magenta+green, and yellow+blue. To combine more subsequent color groups with the appropriate condition can be also form the “neutral grey”.
[0032] This invention related to the usages of neutral grey balance theory. The primary and subsequent color have their color balance relationship, which provides the accurate balanced color value information for pre-determining the ink film thickness. Using the initiative, pro-active control of each color ink film thickness, positively monitoring the requirement of each color printing unit ink film thickness shall maintain the neutral grey condition. This invention also involves the usages of many different measuring methods, continuous determination, automatic adjustment of the inking value to even distribution on the printing plate surface, and then transferring to the substrate surface. Such printed area shall receive an even inking value/ink film thickness/ink density for executing production.
[0033] This invention is the method of initiative, pro-active pre-determination of ink setting which can rapidly and accurately control the ink film thickness, and then the ink film is transferred to the printing plate for continuous production. The printing result of each printed sheet can achieve the consistency and keep within the tolerance. The advantage of this invention is fast to set up the equipment, greatly reduce the ink and material wastage, less demand of operator's color technical skill, remove the subjective decision of color adjustment, and unrestricting of reproduction. High accurate prediction and control of the product's quality is the ultimate advantage.
[0034] This methodology of this invention is an intelligent proactive color determination system, which is combined with the neutral gray balance color theory. During the printing process, the individual production unit inking evenness does not represent the color values in all units and the color imbalance may significantly affect the printing results. Based on the grey balance theory, the primary colors and subsequent colors must be in appropriate proportion to form a neutral gray balanced printing. The pure black (neutral black) color film is used to determine the color value of density/brightness reference for each color composition to form the neutral gray, such a result can ensure the entire printing job achieving balanced color.
[0035] The invention adopts the working principle of the neutral gray balance and monitoring system: the ink dispensing system of each color production unit is equipped with the ink film thickness reading device, continuously measures and extracts of data, calculates and adjusts. By using the grey balance theory, the pre-determined value of black color becomes the reference target for the grey balance component colors to form the appropriate ink film thickness for the grey balance printing. This invention device can prepare the desire ink film in advance and then automatically adjust within its color production unit and no needs to retrieve the inking correction information from the printed job; hence the result can greatly reduce the examination time as well as the speed of grey balance correction.
[0036] Neutral grey color balance component is based on the combination of color values between the primary and subsequent color density and brightness of color gamut value. This invention is creative, initiative, and proactive in measuring the color film thickness to interpret the pigment density, color gamut, brightness value for the color correction value of each color. It is a practical, effective, simple, direct, fast and accurate measuring method compared with a traditional measuring method.
[0037] The invention provides an initiative and proactive intelligent fluid type film monitoring device, comprising a data reading device, a sampling roller, a data conversion system, a comparison system, and a production control system. The data reading device is attached on the drive shaft, and scans film thickness values from the surface of the sampling roller, and then the data will be transmitted through a signal line to a data conversion system, the comparison system sends the correction instructions to the production control system for conducting the correction.
[0038] The device is equipped with an intelligent control system. Such a device comprises the data reading device, the comparison system, and the production control system, and the data conversion system. The data reading device for each production unit will obtain data, and sends the data to the comparison system via the data conversion system. After the comparison system analyzes and determines the film thickness correction plan for each production unit, the production control system executes the control process. The steps are repeated for intelligent control.
[0039] Referring to FIG. 21 , the controlling work flow circuit diagram of determining the grey balance value, measuring, analysis, calculation and execution are summarized as follows: to begin with, the comparison system has been set with the default neutral grey balance value, and then sends the default color film thickness to the reference value circuit. At the same time, the PLC programmable control device attached to the printing units 1 , 2 , 3 , 4 and etc sends commands to the data reading device, to execute the ink film data collection operation. The thickness value is forwarded to the signal receiving system for analysis, and then the ink film thickness comparison unit compares the value against the default setting and determines whether the correction is necessary, if necessary, the amended data will be processed by the amplifier. Finally, the selector will determine the color correction requirement and then return signal to the comparison system. By referencing from the color value and ink film thickness look up table, the correction command will transmit the correction value in real time through the production control system for repeating operation.
[0040] While in production, the device allows an operator to input the new reference value based on the actual requirement to the data comparison system for the real time appropriate adjustment and controlling operation.
[0041] The data reading device of the device can be installed independently, and work back and forth along the drive shaft to scan the surface of the sampling roller for the film thickness data collection (as shown in FIGS. 4 , 5 , 6 A, 6 B).
[0042] The data reading device can also be installed with a rotational measuring head for changing the measurement direction (as shown in FIGS. 7A , 7 B).
[0043] The data reading device can also be installed on the drive shaft with the reflector or similar reflection device which is in 90 degrees angle of measurement between the sampling roller to collect the film thickness information (as shown in FIGS. 8A , 8 B).
[0044] The data reading device can be installed on a fixed rack with a plurality of reading heads; such heads collect the film thickness data from the sampling roller surface (as shown in FIGS. 9 , 10 , 11 A, 11 B).
[0045] The measuring device can be equipped with the following elements:
[0046] i) a single scanning head, which can be traveled back and forth, or work with a rotational reflection device to travel back and forth over the ink film thickness sampling roller to collect data from each color zone (as shown in FIGS. 4 , 5 , 6 A, 6 B, 7 A, 7 B, 8 A, 8 B); or
[0047] ii) a plurality of scanning heads, a series of connected reading heads. The quantity is based on the spacing between the number of ink zones and they will be placed along the sampling roller to collect data from each ink zone (as shown in FIGS. 9 , 10 , 11 A, 11 B).
[0048] The reading speed of a plurality of scanning heads system is faster than that of the single head.
[0049] This invention has a comprehensive evaluation on color values with initiative proactive adjustment features. The data reading device can collect ink zone values from each color production unit, such values will pass through the analyzer to determine the requires ink film for achieving the evenness inking coverage, and then to adjust the suitable inking quantity according to the actual requirement.
[0050] The device is equipped with a compensation system to assess production environment changes such as production speed, operation temperature, humidity and etc for making film thickness compensation and controlling the tolerance deviation.
[0051] There are two choices of selections:
[0052] i) Grey Balance analyzing system: Grey balance analyzing system takes into account the relationship between color unit inking values for achieving the grey balance condition, and compares the value with the “K” Black ink value to achieve grey balance production, then the analyzing system transmits the suitable inking values to each color production unit for increasing or decreasing the ink zones correction for the best grey balance result at minimum deviation.
[0053] ii) Non Grey Balance analyzing system: For special color production, the grey balance analyzing system will be switched off, each color printing unit will resume its independent color assessment initiative proactive analyzing function, each color unit does not have the inter color balance relationship, the operator has the choice of using the number of printing unit and determines the inking value to meet the product requirements.
[0054] The data reading procedure of the device of the invention is:
[0055] 1) Grey Balance production: Based on the product requirement, the pre-determined black “K” value will transmit to the color comparison system for continuous analyzing of the color correction values. The ink film thickness data reading device will continuously collect the inking values from each ink zone through the sampling roller, and the data will be directly provided to the grey balance analyzer for determining each color correction scheme, repeatedly to execute the amendment of ink zone values adjustment through the production control system.
[0056] 2) Non Grey Balance production: Based on the product requirement, specially define each production unit inking value, then transmit the values to the data reading device for continuous analysis of the ink zone values adjustment. The ink film thickness data reading device in each inking unit will continuously collect the ink zone values through the film thickness sampling roller for determining color correction scheme, repeatedly to execute the amendment of ink zone values adjustment through the production control system.
[0057] The use of the neutral grey balance analyzing system requires to input the pre-determined grey balance value as the standard reference data, which comprise precise ink film thickness of the primary and subsequent colors and the density or color brightness values. The reference data is converted into the ink film thickness. The data reading device will be continuously monitor and verify with the pre-determined reference data for correction purpose. The excessive or in-sufficient inking value will be immediately delivered to the production control system console for real time amending of each color production unit for accurate ink film thickness adjustment.
[0058] The installation of data reading device can be classified into internal and external type. The internal type needs to follow the design of the production machine metering system and to determine whether there is enough space available to do so, needs an appropriate installation fixture, and needs permanent fastening of the reading device onto the metering system. The single unit data reading device can be in the form of back and forth traveling. The reading device can be fixed in position with reflective device traveling back and forth or in rotational operation as well as multi units fixed position data reading devices installed on to the fixture, and collects the data from the sampling roller by direct or in-direct contact method for accurate scanning and retrieving the data.
[0059] The external type is the special design of independent mechanical fixture, and the reading device needs to be fastened. The single unit data reading device can be in the form of back and forth traveling. The reading device can be fixed in position with reflective device traveling back and forth or in rotational operation as well as multi units fixed position data reading devices installed on the fixture, and have the installation screws to fasten it onto the metering system, with direct or in-direct contact method to collect data from the sampling roller. In additional, the external unit can also be divided into with and without sampling roller, which depends on the selection method of data collection.
[0060] The film thickness data collecting system can be more than one unit to collect the multiple film thickness measurement data from the metering system. The purpose of multiple data collection can provide more film thickness samples to achieve accuracy by mathematical analyzing method.
[0061] To increase the scanning capability, more than one type of data reading device can be installed within one sampling system for data reading operation.
[0062] The data reading device can employ mechanical type reading, or employ a resistive tensioning reading to detect the surface tension resistance value during the ink film metering, and the value can be used to determine the ink film thickness; besides, it can also be an electromagnetic type, ultrasonic scanning type, or a laser and optical scanner.
[0063] The device can select a particular color data reading device to collect the measurement, which uses the individual color printing unit's independent ink film thickness analyzer to continuously collect the ink film thickness value, to perform real time analyze on each ink zone inking condition, then forwards the amended inking value to the ink dispensing system accordingly.
[0064] This invention device can be used in combination with mechanical, electronic, and digital production equipments.
[0065] The data reading device scanning system can be classified as following: Mechanical reading device, using the mechanical contact to measure the actual ink film thickness; the resistive tensioning reading to detect the surface tension resistance value to determine the film thickness; electromagnetic reading device, using the suitable magnetic wave energy, to absorb, to reflect or to penetrate the ink film on the roller surface; an ultrasonic sensor, comparing the sound wave time traveling difference between the ink film and sensor to determine the changes of film thickness; the laser measuring device, using the laser ray emission and receiving time difference to measure the micro meter distance; the optical reading device such as densitometer, spectral densitometer, imaging device, spectrometer, it can be used to directly analyze the ink film density, contrast, color strength, chromatic result. The above measuring data can determine the grey balance condition by using the reference black (neutral black) color, this is used to initiatively and proactively determine the particular production color printing unit ink film thickness in balancing to each other to form neutral grey, and then proceed printing onto the substrate. Those color without the grey balance relationship will become a special color, that particular production unit can select the pre-determined ink film thickness and disable the neutral grey balance analyzing system, automatically scan, monitor, amend such ink film thickness to fulfill the even coverage on the application roller system to execute printing process.
[0066] The data reading device obtains data through the PLC programmable controller to compute and digitize the result, and then transmit in optical, electronic, digital form to the computer to calculate and determine the ink film thickness, this can provide appropriate correction values to the production control system for amending the ink film thickness.
[0067] FIG. 20 is the conversion chart for the ink film thickness, density, and color brightness value. The market available color substance has carried different fluid body; the fluid type printing ink film thickness is based on its physical characteristic to represent the ink density, color brightness relationship. The look up table is used to record each color unit ink film thickness, density, and color brightness values.
[0068] Based on the above scanning methods, installation means, creating the look up tables, data retrieving, all of these can provide the information for the grey balance analyzer to predict each primary color ink film thickness to achieve the grey balance, and then compare the grey value with the pre-determined “K” reference value. When necessary, increasing, decreasing, or maintaining each color unit's inking value through the optical, electronic, digital transmission method for sending the amendment to the production control console in real time, to initiatively, pro-actively, and continuously execute the color adjustment. Such color value information will be forwarded to each color printing unit's ink zone for pro-actively pre-determining the appropriate ink film for the high quality and accurate grey balance production.
[0069] This invention relates to a kind of initiative, proactive, intelligent controlling device for fluid films. The device can install more than one unit of data reading device or more than one unit of sampling device; it can also be installed more than one unit of data reading devices and more than one unit of sampling device within the metering system to collect multiple fluid films thickness data along the same fluid dispensing zone for determination of the correction value whenever necessary to improve the accuracy of fluid film thickness evenness production.
[0070] This invention provides the device for the initiative proactive intelligent control on the fluid type films, which is equipped with an intelligent controlling system, and the device comprises the data reading device, the comparison system, the production control system, and the data conversion system. The data reading device for each production unit's will obtain data, and deliver the data through the data conversion system to the comparison system to analyze and determine the film thickness correction plan for each production unit to execute the amendment through the production control system and execute the control process in closed loop operation.
[0071] The fluid film correction system and device can be a direct type, which comprises a sampling roller, doctor blade, container, data reading device, PLC programmable control device. The data reading device is used to collect the excess fluid film information and then transmits the command in real time to the PLC programmable control device to control the gap spacing for controlling the allowable fluid to pass through for forming the film thickness.
[0072] The fluid films correction system and device can be an indirect type, which comprises a sampling roller, roller, doctor blade, container, data reading device, PLC programmable control device. The data reading device is used to collect the excess fluid films information then transmits the command in real time bases to the PLC programmable control device to control the gap spacing for controlling the allowable fluid to pass through for forming the film thickness.
BRIEF DESCRIPTION OF THE DRAWINGS
[0073] FIG. 1 : a schematic diagram of an initiative proactive fluid type films controlling method and device.
[0074] FIG. 2 : a schematic diagram of an initiative proactive fluid type films controlling method and device with adoption of the neutral gray balance monitoring system.
[0075] FIG. 3 : a schematic diagram of an initiative proactive fluid type films controlling method and device, each production color unit has its own individual inking control and continuously maintain the color correction continuously and each production color unit does not have any grey color balance relationship.
[0076] FIG. 4 : a schematic diagram of an internal type single unit data reading device, back and forth measuring.
[0077] FIG. 5 : a schematic diagram of an external type single unit data reading device, back and forth measuring without sampling roller attachment.
[0078] FIG. 6A : a schematic diagram of an external type single unit data reading device, back and forth measuring with sampling roller attachment.
[0079] FIG. 6B : a three-dimensional diagram of an external type single unit data reading device, back and forth measuring with sampling roller attachment.
[0080] FIG. 7A : a schematic diagram of a fixed external type single unit data reading device with adoption of the rotational mirror or similar device, by diffract the measuring angle direction back and forth the sampling roller.
[0081] FIG. 7B : a three-dimensional diagram of external type single unit data reading device.
[0082] FIG. 8A : a schematic diagram of a fixed external type single unit data reading device with adoption of the mirror or similar device, by diffract 90 degree the measuring angle back and forth the sampling roller, and this system has attached with the sampling roller.
[0083] FIG. 8B : a three-dimensional diagram of an external type single unit data reading device.
[0084] FIG. 9 : a schematic diagram of a fixed internal type multi unit data reading device measuring.
[0085] FIG. 10 : a schematic diagram of an external type multi unit data reading device without the sampling roller attachment.
[0086] FIG. 11A : a schematic diagram of an external type multi unit data reading device with the sampling roller attachment.
[0087] FIG. 11B : a three-dimensional diagram of external type multi unit data reading device with the sampling roller attachment.
[0088] FIG. 12 : Laser theory
[0089] FIG. 13 : a schematic diagram of a laser distance measurement of the bare sampling roller without carrying the color film.
[0090] FIG. 14 : a schematic diagram of a laser distance measurement of the sampling roller carrying with the color film.
[0091] FIG. 15 : Ultrasonic theory
[0092] FIG. 16 : a schematic diagram of an ultrasonic distance measurement of the bare sampling roller without carrying the color film.
[0093] FIG. 17 : a schematic diagram of an ultrasonic distance measurement of the sampling roller carrying with the color film.
[0094] FIG. 18 : a schematic diagram of an optical color density and color gamut value reflection measurement.
[0095] FIG. 19 : a schematic diagram of an optical color density and color gamut value transmission measurement.
[0096] FIG. 20 : Look up table for Ink film thickness, color density, and color gamut value.
[0097] FIG. 21 : Grey balance color value determination, measurement, analyzing, calculation, and correction execution control circuit diagram.
[0098] FIGS. 22 , 23 : Fluid type film direct correction system and device schematic diagram.
[0099] FIGS. 24 , 25 : Fluid type film in-direct correction system and device schematic diagram.
[0100] FIG. 26 : The proactive intelligent controlling method for fluid printing ink film thickness value vs the traditional passive system color film thickness controlling method.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0101] The following embodiments of this invention with the content for further elaboration:
Example 1
Initiative Proactive Intelligent Controlling Method and Application Device for Fluid Type Films
[0102] See FIG. 1 , an initiative proactive intelligent controlling method for fluid type films device comprises a production control system console 7 , production units 1 , 2 , 3 , and 4 , metering unit 52 , a data reading device 5 , and a referencing quality analyzing system 6 .
[0103] To implement this invention which is a kind of initiative proactive intelligent controlling method for fluid type films device comprising: entering the predetermined metering material reference value to the analyzing device 6 as the monitoring reference usages. The analyzing device determines the metering film thickness from the look up table (table 20 ) which is the relationship between the film thickness and material requirement value. By giving command to the dispensing system for delivering the appropriate amount of material to the metering unit 52 and execute the even film metering via the sampling roller 9 ; operate the data reading device 5 to measure the film thickness from the sampling roller 9 , obtain the data and transmits to the analyzing system 6 against the film thickness reference for comparison. If the comparison result is not acceptable, the analyzing system 6 will deliver in real time the film thickness correction value to the production control system 7 for controlling the dispensing system through the metering unit to correct the production film thickness. The above description is a repeatedly operation process, it can rapidly provide the film thickness to achieve the reference range, and maintain within the narrowest tolerance deviation, continuously deliver onto the substrate for production. It can maintain the highest quality result and achieve the closest tolerance as well as minimum wastage. For each production unit, the even film thickness does not have any color balance relationship, the operator can freely determine the film thickness setting to achieve the product requirement.
[0104] Any similarity of the following examples' methodologies and devices to this example will not be repeated.
Example 2
Initiative Proactive Intelligent Controlling Method and Application Device for Fluid Type Films with the Adoption of the Neutral Grey Balance Production Technology
[0105] See FIG. 2 , a device comprises a production control system 7 , production units 1 , 2 , 3 , and 4 , metering unit 52 , data reading device 5 , and the neutral grey balance comparison system 6 . Based on the pre-determined printing color sequencing order, freely place the black, cyan, magenta, and yellow ink onto the printing units 1 , 2 , 3 , and 4 . Enter the pre-determined black ink value to the neutral grey balance analyzing device 6 as the neutral grey balance requirement referencing usages. The analyzing device will determine the metering film thickness from the look up table (table 20 ) which is the film thickness and material dosage value. The black, cyan, magenta, and yellow inking unit data reading device 5 will measure the film thickness from the sampling roller 9 , by using the initiative and proactive method to provide the neutral grey balance information to the analyzing device 6 to compare with the pre-determined black inking value. If it is not acceptable, it calculates the grey balance value for the neutral grey balance component colors to determine the correction ink film thickness value, and transmit to the production control system 7 , by giving command to each printing unit inking dispensing system to deliver the appropriate amount of printing ink to the metering unit 52 and execute the ink film metering. The above process is a repeated operation, it can be highly accurate to provide the film thickness for achieving the reference range and maintaining within the tolerance, before delivering to the production line for production, as it is an initiative proactive mode, automatically makes correction in real time bases, continuously maintain the highest quality result and achieves at the closest tolerance as well as minimum wastage.
Example 3
Initiative Proactive Intelligent Independent Production Controlling Modular for Controlling the Fluid Type Film Thickness
[0106] See FIG. 3 , for example in each printing unit, the special color ink can be chosen in printing unit 1 for production. The data reading device 5 will initiatively and proactively measure the color data from each ink zone. The unevenness ink zone result will be sent directly to such unit's ink zone controller 8 in real-time for repeated adjustment, without using the production control system 7 for correction. The operator can also use the production control system 7 as the optional choice for changing the ink value(s). Any similarity to this embodiment will not be repeated.
Example 4
Built-In Monitoring Type of an Initiative Proactive Intelligent Controlling Modular for Controlling the Fluid Type Film Thickness
[0107] See FIG. 4 , provided is a housing of the production equipment 13 . A single data reading device is attached to the drive shaft 10 , the data reading device 5 travels back and forth as the arrow direction along the drive shaft 10 , carries the scanning head back and forth, accurately reads the ink film thickness from the surface of the ink film thickness sampling roller 9 . Using optical, electronic, digital transmission connection 11 delivers the data to the PLC programmable control device 12 for digitize the reading; it is an initiative and proactive production system for continuous monitoring and correction usages.
Example 5
Independent Single Piece External Type Monitoring Device of an Initiative Proactive Intelligent Controlling Modular for Controlling the Fluid Type Film Thickness
[0108] See FIG. 5 , the production machine is not equipped with a sampling roller. This invention system needs to design an independent mechanical anchorage device, equipped with a frame 40 , by using fastening screws 41 to secure the connection bars 42 against the production machine's metering system housing 13 . Drive shaft 10 is equipped with a single data reading device 5 with operating back and forth as the arrow indication direction and working along the drive shaft 10 , to accurately scan the ink film thickness from the surface of the sampling roller 9 for the thickness value. Any similarity to this example will not be repeated.
Example 6
Independent Single Piece External Type Monitoring Device of an Initiative Proactive Intelligent Controlling Modular for Controlling the Fluid Type Film Thickness
[0109] See FIGS. 6A , 6 B, the system is equipped with a sampling roller. The system basic functionality is similar to that of FIG. 5 , and the only different is that the ink film thickness sampling roller 9 is installed at the frame 40 as part of the single piece monitoring modular. Any similarity to the embodiment 4 will not be repeated.
Example 7
Independent Single Piece External Type Monitoring Device of an Initiative Proactive Intelligent Controlling Modular for Controlling the Fluid Type Film Thickness
[0110] See FIGS. 7A , 7 B, the system is equipped with a sampling roller. The system needs to design an independent anchorage device, equipped with an installation frame 40 , by using fastening screws 41 to secure the connection bars 42 against the production machine metering system housing 13 . A single data reading device 5 is fixed onto the bracket. The reading device can collect the ink film thickness from the rotational reflector or similar reflection device, by changing the angle of measurement in between the sampling roller 9 surface, to accurately scan the ink film thickness for reading the value. Any similarity to the example 4 will not be repeated.
Example 8
Independent Single Piece External Type Monitoring Device of an Initiative Proactive Intelligent Controlling Modular for Controlling the Fluid Type Film Thickness
[0111] See FIGS. 8A , 8 B, the system is equipped with a sampling roller. The system needs to design an independent mechanical anchorage device, equipped with an installation frame 40 , by using fastening screws 41 to secure the connection bars 42 against the production machine metering system housing 13 . A single data reading device 5 is fixed inside the frame 40 , the reflector or similar reflective device is attached to the drive shaft 10 , back and forth traveling as arrow indicated direction, the reflector or similar reflective device has changed the measurement direction by 90 degree angles between the sampling roller 9 surface. Any similarity to the example 4 will not be repeated.
Example 9
Built-In Type Multi Units Monitoring Device of an Initiative Proactive Intelligent Controlling Modular for Controlling the Fluid Type Film Thickness
[0112] See FIG. 9 , the production equipment housing 13 with permanent frame equipped with multi data reading devices 5 , accurately read the film thickness values from the surface of the film thickness sampling roller 9 . Any similarity to the example 4 will not be repeated.
Example 10
External Type Independent Multi Monitoring Device of an Initiative Proactive Intelligent Controlling Modular for Controlling the Fluid Type Film Thickness
[0113] See FIG. 10 , the system is equipped with a sampling roller. The system needs to design an independent mechanical anchorage device, equipped with an installation frame 40 , by using fastening screws 41 to secure the connection bars 42 against the production machine metering system housing 13 . The multi unit data reading device 5 is fixed onto the permanent structure to accurately scan the ink film thickness values from the surface of the sampling roller 9 . Any similarity to the example 4 will not be repeated.
Example 11
Independent Multi Heads External Type Monitoring Device of an Initiative Proactive Intelligent Controlling Modular for Controlling the Fluid Type Film Thickness
[0114] See FIG. 11A , 11 B, the system is equipped with a sampling roller. The system basic design is similar to that of FIG. 9 , and the only different is that an ink film thickness sampling roller 9 is installed onto an independent anchorage device 40 . Any similarity to the example 4 will not be repeated.
Example 12
Laser Type Monitoring Device of an Initiative Proactive Intelligent Controlling Modular for Controlling the Fluid Type Film Thickness
[0115] See FIG. 12 , provided is a laser construction. The system comprises active material 17 , which is placed between two reflective type mirrors 15 , 16 . A resonator 19 is formed by two reflective minors and the laser reflective material, by using this to provide the light beam. The atom of the laser active material has been activated by the external energy 21 , excited to the higher energy lever condition. The light beam bounces back and forth 20 between two minors and then forms an accurate fixed speed of light beam. To release the light beam from the resonator, one of the mirrors 16 can only rebound half of the light beam; this can allow the other half of the laser light beam 18 to freely go through the minor.
[0116] See FIG. 13 , the data reading device 5 has been equipped with the laser resonator device, laser beam resonator, and light beam receiver to measure the light beam emission and receiving time, and calculate and record the non ink film bare roller surface 22 and the distance 31 between the data reading device. The mathematical formula is as below: displacement=speed of light×the total light traveling time between emission and receiving/2 times (Back and forth journey).
[0117] See FIG. 14 , the data reading device 5 has been equipped with the laser resonator device to measure the time between the light emission and receiver, and calculate and record the ink film thickness surface 23 and the distance 32 between the data reading device. The displacement result is used to calculate the ink film thickness. The ink film thickness mathematical formula as: the ink film thickness=the bare sampling roller without the ink film displacement 31 −the sampling roller adhering with ink film displacement 32 .
Example 13
Ultrasonic Scanning Type Monitoring Device of an Initiative Proactive Intelligent Controlling Modular for Controlling the Fluid Type Film Thickness
[0118] See FIG. 15 , provided is an ultrasonic emitter 24 which is an electro-gas type ultrasonic generator 27 . Piezoelectric emitter comprises two pieces of transmitter chip 25 and a resonance plate 26 , and the ultrasonic resonance is generated by applying an external pulse signal onto the transmitter chip and creates vibration. Conversely, the ultrasonic receiver 30 comprises two piezoelectric chips 25 , the resonance plate 26 receives the external ultrasound 29 , and the ultrasonic wave energy will vibrate the resonance plates, which can convert this mechanical motion to electrode signal for time computing usages.
[0119] See FIG. 16 , the data reading device 5 is equipped with the ultrasonic emitter to measure the time between the sound wave emission and receiving, and calculate and record the bare roller surface 22 without ink film and the distance 31 between the data reading device. The ink film thickness mathematical formula as: displacement=340 (the speed of sound)×the total sound wave traveling time between emission and receiving/2 times (Back and forth journey)
[0120] See FIG. 17 , the data reading device 5 is equipped with the ultrasonic emitter, to measure the time between the sound emission and receiver, and calculate and record the ink film thickness surface 23 and the distance 32 between the data reading device. The displacement result is used to compute the ink film thickness. The ink film thickness mathematical formula as: the ink film thickness=the bare sampling roller without ink film displacement 31 −the sampling roller adhering with ink film displacement 32 .
Example 14
Optical Type Measuring Device of an Initiative Proactive Intelligent Controlling Modular for Controlling the Fluid Type Film Thickness
[0121] See FIG. 18 , provided is an optical color density and color gamut brightness reflective measuring. The measuring system comprises a standard illumination lighting 43 , optical lenses construction component 44 , filter 45 , spectrometer 46 , and optical computing device 50 . The reading method is to measure the light reflective data 48 from the reflective material 47 . By using the appropriate light source D50, D60 to shine over the measuring subject, the reflective measurement such as paper 47 . Such light source penetrates through the examination material to the substrate layer, and then bounces back through the examination material with carrying certain density (the rate of filtering) to reduce the intensity for computing the color density or color brightness or individual color value digitally. The measuring material under illumination by lighting system, the amount of light of reflection, through the optical lenses component and filter, are directly transmitted to the spectrometer or digital imaging device (CCD, CMOS) for measurement. Use the optical computer to accurately analyze the color density or color gamut brightness values.
[0122] See FIG. 19 , provided is an optical color density and color gamut brightness penetration measuring. The measuring system comprises a standard illumination lighting 43 , optical lenses construction component 44 , filter 45 , spectrometer 46 , and optical computing device 50 . The reading method is to measure the light penetration data 48 through the sampling material 49 . Use the appropriate light source D50, D60 to shine onto the measuring subject, and get the penetrative measuring from the transparent film media 49 density. Such light source will depend on the density of the measuring material (rate of transparent) to reduce the intensity for computing the color density or color gamut brightness or individual color value digitally. The measuring material under illumination by lighting system, the amount of light of penetration, through the optical lenses component and filter, are directly transmitted to the spectrometer or digital imaging device (CCD, CMOS) for measurement. Use the optical computer to accurately analyze the color density or color gamut brightness values.
[0123] Implementation of the method for the fluid type films is equipped with the direct and indirect controlling systems and devices.
[0124] Set a fixed distance 33 in mechanical way that the fluid thickness can pass through. The excessive fluid film 37 will be collected by the adjustable mechanical spacing roller 34 and doctor blade 35 . This controlling system is equipped with data reading device 5 for monitoring whether there is any excessive fluid film and real time re-adjust the dispensing value and re-set the distance 33 for controlling the film thickness. The doctor blade installation can be a direct and in-direct method.
Example 15
[0125] FIG. 22 and FIG. 23 show a direct-type system and device. The sampling roller 9 is equipped with a doctor blade 35 with pre-determined distance for collecting the excessive fluid type film. Such a distance 33 is the spacing which can make the fluid films pass through. The excessive fluid film 37 will be removed by the doctor blade and store at the container 36 for re-cycling back to the dispensing duct. The container is equipped with a data reading device 5 , which is used to monitor whether there is any excessive fluid film collected. If the device 5 has detected signal, then the amendment command will be sent in real time to the PLC controlling unit 12 for digitize the signal. The material duct changes the dispensing value and the spacing 33 by the doctor blade 35 for direct control of the film thickness. This system is an initiative and proactive consistent monitor to amend the fluid film thickness requirement.
Example 16
[0126] FIG. 24 and FIG. 25 show an indirect-type system and device. The sampling roller 9 is equipped with a roller 34 with pre-determined spacing to collect the excessive fluid film. The roller surface is equipped with a tight fit doctor blade 35 . Such a distance 33 is the spacing for fluid films to pass through. The excessive fluid films 37 will be removed by the pre-determined spacing roller; the tightly contacted doctor blade will continuously collect the excessive fluid from the pre-determined spacing roller and store at the container 36 for re-cycling back to the dispensing duct. The container is equipped with a data reading device 5 , which is used to monitor whether there is excessive fluid films collected. If the device 5 has detected signal, then the amendment command will be sent in real time to the PLC controlling unit 12 for digitizing the signal. The material duct amends the dispensing value and re-determines the spacing 33 by the pre-determined spacing roller 34 for direct control of the film thickness. This system is an initiative and proactive consistence monitor to amend the fluid film thickness requirement.
Example 17
[0127] FIG. 26 : show the different work flow for the proactive intelligent controlling method for fluid type color printing ink film thickness value vs the traditional passive color film thickness controlling method.
[0128] The proactive intelligent controlling method for fluid printing ink film thickness value work flow has begun with:
a) color film delivered by production equipment to begin the production; b) by using the proactive control system for checking color film thickness value to analyze, the color film thickness whether acceptable or out of range; c) if out of range, the closed loop repeated adjustment for color film thickness to determine the new thickness value for color film delivered by production equipment and continuous the next production cycle; and d) if acceptable, the correct color film will deliver onto the substrate for finishing printing to become finished product.
[0133] The traditional passive color film thickness controlling method work flow has begun with:
a) color film delivered by production equipment to begin the production; b) whatever color film thickness on the equipment will deliver onto the substrate for finishing production to become finished product; c) after the product being made, the passive system of quality control module to conduct the quality inspection process for analyzing whether the finished product is unacceptable or not; d) for any unacceptable product shall become defect products which has already been produced; and e) based on the defect result to determine the correction value, and then execute the delivering correction color film thickness process for entering the next production cycle.
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A method for monitoring production of a fluid film, including: activating a dispenser to deliver appropriate material from a storage duct to a metering system for even distribution of a fluid film; allowing the fluid film to pass a sample retrieving roller; measuring the fluid film on the sample retrieving roller using a data reading device to obtain film thickness data; transmitting the data to an analyzer to examine the data against a predetermined reference value; transmitting a comparison result in real time by the analyzer to a production equipment controlling console; controlling the storage duct to dispense material through the material metering system and adjusting the film thickness; repeating the above steps to make a film thickness within the reference range; and maintaining the thickness at the narrowest tolerance deviation, and continuously delivering the film onto a substrate for production.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to time locks for bank vaults and, more particularly, to a low current drain battery operable timer for releasing a gravity operated mechanical block.
2. Description of the Prior Art
For decades, mechanical timers have been employed as time locks for bank vaults. Such mechanical timers must be accurate despite environmental changes and wear. To eliminate wear as a variable, substantial maintenance has been required. The setting of mechanical time locks is generally complicated and missetting often occurs.
Various electrically operated time locks can be used but the power consumption is relatively high. With high power consumption, battery power becomes a predominant problem for long term settings. Reliance upon a source of alternating current from conventional power sources or backup generators will not satisfy criteria for good practice.
Electromechanical time locks for bank vaults generally suffer from all of the wear and maintenance problems attendant mechanical locks and generally have high power requirements. While the electrical timers in electromechanical locks are generally sufficiently accurate, the mechanics activated to lock and unlock a bank vault require high tolerances subject to malfunction due to contamination or are easily detuned to the state of inoperability and require meticulous adjustments.
SUMMARY OF THE INVENTION
A gravity operated vertically rectilinearly translatable block is positionable in a relaxed position to permit opening of a bank vault door. Upon setting of the timer, an upwardly directed spring bias is imposed upon the block to raise the block to a raised position which position inhibits translation or repositioning of a bar; such repositioning is necessary to open the vault door. Actual upward translation of the block will occur in response to spring bias only after the timing mechanism has been previously set and upon closing of the vault door. A timing mechanism includes a crystal oscillator for generating a stream of pulses at a predetermined frequency. After division, the pulses are counted by units, decades and hundreds and produce outputs to an input to each of corresponding comparators. Settable thumb wheels are adjusted to provide a visual indication of the time lock period and provide a further input to each of the comparators. Upon correspondence at the comparators of the counted inputs with the set inputs, an output signal is generated to actuate electromagnetic devices for releasing the block and permit the block to drop by force of gravity to its relaxed position. Thereafter, the vault door may be opened. Failsafe means are incorporated to eliminate the possibility of generating a false output signal due to electronic component failure. The low battery drain of the timer permits use of conventional batteries as power sources. Various indicators are provided to reflect the status of various of the components.
It is therefore a primary object of the present invention to provide a fail safe time lock for a bank vault door.
Another object of the present invention is to provide a gravity operated mechanical release for permitting opening of a bank vault door upon lapse of a predetermined time period.
Yet another object of the present invention is to provide a time lock for a bank vault door settable by translation of a single lever.
Still another object of the present invention is to provide a time lock for a bank vault door which is settable long prior to closing of the vault door.
A further object of the present invention is to provide an electronic timer for comparing the number of pulses in a pulse train with an electrical input generated by time indicating thumb wheels in order to generate an output signal for releasing a bank vault time lock.
A still further object of the present invention is to provide a low current drain battery operated timer for releasing a lock block of a bank vault time lock.
A still further object of the present invention is to provide a fail safe timer for precluding inadvertent unlocking of a bank vault time lock due to component failure.
A still further object of the present invention is to provide a method for selectively mechanically locking a bank vault door.
A still further object of the present invention is to provide a method for timing the unlocking of a bank vault time lock.
These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention may be described with greater clarity and specificity with reference to the following drawings, in which:
FIG. 1 is a perspective view of the timer;
FIG. 2 is an exploded isometric view of the front mounted mechanical components;
FIG. 3 is an isometric exploded view of the rear mounted components;
FIG. 4 is a cross sectional view illustrating the location within the case of both the mechanical and electrical components;
FIG. 5A illustrates the front mechanical components after latching;
FIG. 5B illustrates the front mechanical components after the timer has tripped;
FIG. 6A illustrates the position of the mechanical components subsequent to latching and prior to closure of the vault door;
FIG. 6B and 6C illustrate the operation of the mechanical components upon tripping of the latch;
FIG. 7 is a partial cross sectional view illustrating the position of the mechanical components subsequent to latching and prior to closure of the vault door;
FIG. 8 illustrates the position of the mechanical components after latching and closure of the vault door;
FIG. 9 illustrates the position of the mechanical components prior to latching and while the vault door is open; and
FIGS. 10A, 10B and 10C illustrate the electronic timer circuitry.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Timers for controlling or regulating the time of opening a bank vault door have been in use for a period of years. These timers are generally activated upon closure of the bank vault door. Often, such a timer must be set to correspond with the time of closing of the bank vault door. This requirement has and will cause problems due to human error and forgetfulness. All bank vault timers have certain mechanical components which are actuated either by mechanical clockwork devices or by electric or electronic counting or timing circuits. Because mechanical devices tend to wear, they must be carefully designed to preclude or minimize inoperability due to such wear. Moreover, the mechanical elements, which are repositionable with respect to one another, must be carefully designed to prevent inadvertent jamming and resulting inoperability; and, the cost of maintenance of these mechanical time locks exceeds one dollar per day.
When electronic circuitry is used to provide a timing function, setting of the time period must be relatively easy, foolproof, and indicated to an operator. Preferably, initiation of the timing cycle should correspond with actuation of a mechanical lock out feature cooperating with the bank vault door. That is, the mechanical lock out feature must not be engagable without a commensurate actuation of the electric or electronic timer. Power failure is always a potential problem at any installation; the electrically energized timer should therefore be capable of automatically switching to a battery power source without jeopardizing the timing function underway in the event the main power source fails.
As there are many types of bank vaults, a timer for a bank vault door should be readily adaptable to be used with any of a plurality of presently available bank vaults. Such universality of use increases the potential market and therefore, with higher sales volume, the costs can be maintained reasonably low. To further enhance a low cost timer, both the mechanical and electrical components must be relatively inexpensive to manufacture and assemble without compromise of quality.
Referring to FIG. 1, there is shown a bank vault timer 10 having a case 12 for enclosing the operative elements. Electrical power is provided to the timer via electrical conductors 14 entering through a slot 16 in case 12. The face of the case includes thumb wheels 18,20 and 22 having corresponding numerals 24,26 and 28, respectively, to indicate the number of hours that must lapse before a bank vault door can be opened. A display 30 may be incorporated to provide a visual indication of the number of hours remaining before the bank vault door can be opened. Switch 32 is a reset switch. Switch 34 may be incorporated to control operation of display 30. A further switch 36 is a power on/power off switch.
Most presently used bank vault doors include a rectilinearly translatable rod which translates as a function of locking and unlocking of the door. Depending upon the manufacturer and the door model, this rod may be more or less accessible. Timer 10 includes means (see FIG. 4) for mounting the timer in conjunction with a surface adjacent the translatable rod. Because of different door configurations, the timer may have to be mounted at different elevations with respect to the rod. For this reason, timer 10 may include two ports 38 and 40. Depending upon the mounting position of the timer, the rod will penetrably engage one of these ports. By restricting translation of the rod within timer 10, opening of the door will be precluded. Accordingly, timer 10 operates upon the underlying principle of preventing the requisite translation of the rod to a degree sufficient to prevent opening of the door unless a predetermined time period has elapsed. A further feature of timer 10 permits setting of the timer while the bank vault door is open with the rod in full penetrable engagement with the timer. This latching function is initiated by raising arm 44 extending through vertical slot 46 in case 12. Upon raising arm 44, it will become latched and reset switch 32 will be actuated and the timer will begin to run. The arm will be unlatched when the timer reaches the lapsed time values set on the dials (it may be noted that the time values can be set on the dials before or after reset). Upon closing of the vault door, and partial or full retraction of the rod from within timer 10, repenetration of the rod into the timer will be precluded and the door cannot be opened.
Referring to FIG. 2, there is shown a base plate 50 for attachment to a mounting surface attendant the vault door. A body block 52 is secured to base plate 50 by means of allen head bolts 54 which threadedly engage corresponding cavities 56 in the base plate. The body block includes a passageway 58 for routing conductors 14 therethrough. A cylindrical passageway 60, aligned with port 38, extends through body block 52 for receiving the rod. A similar cylindrical passageway 62 extends from port 40 through the body block. It is to be understood that only one of the cylindrical passageways will in fact be used but by forming two such cylindrical passageways within the body block, timer 10 may be used with differently configured vault doors. A cylindrical cavity 64 is configured to receive and mountingly support solenoid 66. A similar cylindrical cavity 68 mountingly supports solenoid 70. A slot 72 extends transversely through body block 52. A plate 74 is slidably attached to face 76 of body block 52 by allen head bolts 78,80 and 82 penetrably engaging slots 84,86 and 88 in the plate and threadedly engaging threaded cavities 90,92 and 94, respectively. A slot 96 in plate 74 is superimposed with slot 72 in body block 52 upon mounting of the plate. A miniature switch 100, having an actuating roller arm 102, is mounted upon body block 52 with bolts extending through the switch into threaded engagement with threaded cavities 104,106. A bar magnet 108 is mounted upon plate 74 by bolts 110,112 engaging threaded cavities 114,116. A pair of magnetic switches 118,119 are secured to body block 52 by bolts 120,122 engaging threaded cavities 124,126. Switches 118,119 are magnetically switched closed in response to the proximity of magnet 108 when plate 74 is raised. These switches, when closed, energize lighted displays to indicate AC and DC power availability status, respectively.
Referring to FIG. 3, the structure attendant the rear side of body block 52 will be described. A rectangular shaped recess 130 is formed in body block 52 to slidably receive lock block 132. The lock block is of a thickness commensurate with the depth of recess 130. Moreover, the lock block is of a length less than that of the recess to permit and accommodate longitudinal translation of the lock block within the recess. The lock block includes a central plate 134 having rectangular block members 136,138 disposed at opposed ends. A post 140 extends downwardly from block member 138 and supports a coil spring 142. A floating cam 144 includes a cavity disposed in the upper surface thereof for translatably receiving post 140. The floating cam includes two distinct elements. A cam element 146 penetrably engages slot 72 in body block 52. The cam element includes an inclined surface 148 for engaging the roller of roller arm 102 extending from switch 100. The floating cam includes a pair of shoulders 150,152 vertically displaced from one another and in general vertical alignment with one another. A latch 160 includes a pawl 162 extending horizontally therefrom. The latch is secured to each of plungers 164,166 of solenoids 66,68. A coil spring 170 may be mounted upon plunger 166 along with a washer 172 to bear against the rear edge of latch 160. A similar coil spring 174 may be mounted upon plunger 168 along with a washer 176 to bear against the rear edge of the latch. A post 180 may be formed in recess 130 to bear against and serve in the manner of a pivot pin in cooperation with curved edge 182 of latch 160.
Referring to FIG. 4, there is shown a partial cross sectional view of timer 10. Base plate 50 is secured to mounting surface 190 of a bank vault door by means of countersunk mounting bolts 192. Cover 12 is secured to back plate 50 by countersunk bolts 194. The space within cover 12 anterior of body block 52 houses a thumb wheel module 196, of which thumb wheel 18 is partly illustrated. Similarly, a module for display 30 is mounted within the cover on the far side of plate 74 (see FIGS. 1 and 2). The space generally below module 196 and the display module and anteriorly of body block 52 houses circuit boards 198,200 containing various electronic components necessary to perform the timing and display functions. A switch 202, which is not a user accessible switch, is a test switch. It permits accelerated counting from one count per hour to one count per second. Stand offs, such as stand off 204, may be secured to and extend anteriorly from body block 52 to support the circuit boards.
The quiescent and active functions of plate 74 and anteriorly extending arm 44 will be described with joint reference to FIGS. 5A and 5B. To begin the timing cycle, arm 44 (note FIG. 1) is raised along slot 46 and plate 74 will be similarly raised, as indicated by arrow 210. The lower end of slot 96 in plate 74 (see FIG. 3) will bear against the lower edge of cam element 146 of floating cam 144 to raise the floating cam. In the raised position, the floating cam will become latched by engagement of pawl 162 with shoulder 150. Roller arm 102, resting upon inclined surface 148 in the quiescent state, will roll onto surface 154. The arm will pivot toward miniature switch 100 and the state of the switch will change. This switching function will provide a triggering signal to the timing circuit via conductors 212. After the initial upward movement of arm 44, an operator may release the arm. Upon release, plate 74 will drop to its lower position, as depicted by arrow 214. The sliding movement of the plate is accommodated by bolts 78,80 and 82 penetrably engaging slots 84,86 and 88. Upon downward positioning of plate 74, floating cam 144 will remain in the raised and latched position and the resulting relative repositioning between the plate and the floating cam is accommodated by slot 96. Further upward movement of arm 44, with commensurate translation of plate 74, will have no effect upon repositioning of the floating cam.
Upon termination of the timing period, floating cam 144 will become unlatched and it will drop downwardly, which translatory movement is accommodated by slot 96. At the lower position of the floating cam, the roller of roller arm 102 will be transposed from surface 154 to inclined surface 148. The resulting pivotal movement of the roller arm will produce a control signal upon conductors 212. Magnetic switch 108, attached to body block 52, will change state in response to vertical translation of magnet 118 as a result of vertical translation of plate 74. The change in state of magnetic switch 108 is conveyed to circuitry by means of conductors 216.
The latching and unlatching of floating cam 144 will be described with joint reference to FIGS. 6A, 6B and 6C, which figures illustrate a posterior view of body block 52. Plunger 166 of solenoid 66 extends into recess 130 to loosely engage the upper end of latch 160 by means of a pin 164. Coil spring 170, bearing against the latch via washer 172, urges the latch away from side wall 131. Upon energization of solenoid 66, plunger 166 is retracted to draw the upper end of latch 160 toward side wall 131. Plunger 168 of solenoid 68 is secured to the lower end of latch 160 by means of a further pin 164. The lower end of the latch is urged away from side wall 131 of recess 130 by coil spring 174 bearing against washer 176 adjacent the latch. Upon energization of solenoid 68, plunger 168 will retract to draw the lower end of latch 160 toward side wall 131. Post 180 loosely supports curved surface 182 of latch 160 and serves in the manner of a pivot point upon retraction of plunger 166.
Shoulder 152 of floating cam 144 rests upon pawl 162 of latch 160 when the floating cam is in the lower position (as shown in FIG. 5B). When the floating cam is in the raised position (as shown in FIGS. 5A and 6A) shoulder 150 rests upon pawl 162. Upon actuation of either or both of solenoids 66,68, latch 160 will be drawn toward side wall 131. The resulting repositioning of the latch will disengage pawl 162 from shoulder 150. Upon such disengagement, upward support for the floating cam in its raised position is non existent. Floating cam 144 will then drop in response to gravity and in response to the force exerted by coil spring 142 disposed between the floating cam and block 138 of lock block 132. As a guide to vertical translation of the floating cam, post 140 extends into cavity 158 developed in the upper end of the floating cam. This function is more clearly illustrated in FIG. 6B wherein arrow 220 represents retraction of plunger 166 and pawl 162 is shown clear of shoulder 150 to permit the floating cam to drop. Preferably, solenoid 66 is energized slightly prior to energization of solenoid 68 in order to obtain a cocking action of latch 160, as illustrated. The subsequent retraction of plunger 168 as a safety measure in the event solenoid 66 doesn't operate or in the event plunger 166 is not retracted, as particularly illustrated in FIG. 6C and depicted by arrow 222, laterally displaces the lower part of the latch to permit downward movement of floating cam 144, as depicted by arrow 224 by drawing latch 162 clear of shoulder 150.
Upon upward movement of arm 44 and accompanying plate 74, the floating cam will be raised, as discussed above. The upward translation of the floating cam will cause curved surface 159, upwardly of shoulder 150, to bear against the lower edge of pawl 162 of latch 160 and cause translation of the latch toward side wall 131. Such translation will permit passage of shoulder 150 past pawl 162. Upon such passage of shoulder 150, latch 160 will be forced away from sidewall 131 by coil springs 170,174.
A bank vault door includes a rod 230 which translates linearly in response to locking and unlocking of the door lock mechanism. Such rod is depicted in FIGS. 6A, 7, 8 and 9. In the embodiment illustrated, rod 230 extends into cylindrical passageway 62. When the vault door is open, rod 230, disposed within cylindrical passageway 62, extends across recess 130 (as depicted in FIG. 6A). To accommodate this position of the rod, block member 136 of lock block 132 is dimensioned and positioned beneath rod 230, as shown in FIG. 7. The interference between block member 136 and the rod precludes upward movement of lock block 132. Nevertheless, for reasons described with respect to FIGS. 6A, and 6B and 6C, floating cam 144 is free to translate upwardly and downwardly without commensurate movement of the lock block. Upon retraction of rod 230, which will occur upon closing of the vault door, rod 230 is translatably repositioned out of recess 130. With such withdrawal of the rod, it will no longer interfere with block member 136. Accordingly, lock block 132 is free to be raised. In the raised position, as depicted in FIG. 8, block member 136 is positioned in general alignment with cylindrical passageway 62 and will effectively preclude translation of rod 230 into recess 130 in body block 52. Without such translation of rod 230, the vault door cannot be opened.
Upon upward translation of floating cam 144 and locking it in place by engagement of pawl 162 with shoulder 150, coil spring 142 will be compressed. The compressed coil spring will exert an upward force upon block member 138 of lock block 132 and urge upward movement of the lock block and it will be raised, as discussed above.
On completion of the time interval set by timer 10, solenoids 66,68 will be energized to retract the respective plungers. The act of retracting the plungers will reposition latch 160 to permit floating cam 144 to drop. The resulting lowered position of the floating cam, as depicted in FIG. 9, will permit extension of coil spring 142 and remove the upward urging bias against block member 138. Accordingly, lock block 132 will drop to the position depicted in FIG. 9. The dropped lock block will reposition block member 136 to a point out of alignment with cylindrical passageway 62. Thereafter, rod 230 may be translated along the cylindrical passageway and through recess 130.
In certain applications, it may be preferable to locate timer 10 such that cylindrical passageway 60 receives rod 230 of the vault door. In such event, the above described procedure would be duplicated except that block member 138 would serve the functions of restricting and accommodating passage of rod 230 within cylindrical passageway 60 across recess 130.
As alluded to above, timer 10 can be set by actuating reset switch 32 and upward movement of arm 44 with the door open. Such upward movement will latch floating cam 144 in its upper position. However, because of interference between rod 230 and block member 136, the lock block will not be reset. Nevertheless, the timing function will have been triggered and the time period would be counting. Upon closing of the vault door, the retraction of rod 230 would remove the restraint against block member 136 and the lock block would rise to block further penetration of rod 230 into recess 130. Thus, the setting of timer 10 can be effected long before it is time to close the vault door and the timing function will be under way even while the vault door is open and the vault is in use.
The countdown timer circuit for actuating the latch to release the lock block and permit opening of a bank vault door will be described with joint reference to FIGS. 10A, 10B and 10C. Before proceeding with a detailed description of the circuit, it may be beneficial to provide an overview of the function of the major sections. The timer circuit is a three digit timer that counts up to 199 hours. It requires a very low current while maintaining adequate accuracy and provides ease of operation. The elapsed time is set by three thumb wheels. Thereafter, actuating the reset button will start the count at zero and continue the count until the preset time is reached. A signal is generated on completion of the time period to energize the solenoids and actuate the latch to permit the lock block to drop out of interfering relationship with the bank vault door rod. The total current drain of timer 10 is approximately 250 milliamps. This low current drain provides, from a widely available commercial battery, 63 hours of operation without charge. These figures compare favorably with other timing circuits drawing approximately 3 amps per hour.
Because it may be useful to obtain an overview of the timer prior to a discussion of the individual components and their discrete functions, the following synopsis is presented. Comparators IC4, IC5 and IC6 form the heart of the timer. Upon agreement between the twelve inputs from the three counters, IC1, IC2 and IC3, with the twelve inputs from the three thumb wheel switches, as determined by comparators IC4, IC5 and IC6, the output of comparator IC6 goes high. The pulse generated by comparator IC6 terminates the operation of the timer. That is, the output of the comparator increases from 0.3 volts to approximately 2.5 volts. This pulse is transmitted along conductors 336 and 326 to pins 4 of counters IC1, IC2 and IC3 to inhibit further counting. Simultaneously, the pulse is transmitted along conductor 386 to Darlington transistors TP1 and TP2 to initiate opening of the vault door.
More particularly, three up/down digital counters, IC1, IC2 and IC3, are driven by precision crystal oscillator IC10 and CMOS multivibrator IC7 having two invertor circuits and a divider and providing an output frequency of 1.20058 Hz. IC8 counts down from 1.20058 Hz to 1 Hz per hour; additionally, it generates a 1+ Hz output signal to display active operation of the system. Counters IC1, IC2 and IC3 may be of the type known as 74LS190. The output of the counters is applied to three four-bit comparators, IC4, IC5, IC6, which may be of the type known as 74LS85. The three thumb wheels provide an input to the three comparators in a binary coded decimal mode. Once the input number is applied and the reset switch actuated, the counters will count up from zero to the number corresponding with the input from the respective thumb wheel switch. The last comparator generates a stop pulse. The stop pulse energizes a Darlington amplifier (TP1) which provides the requisite current to operate one of the solenoids. A slight time delay will occur before a second Darlington amplifier (TP2) is energized to operate the second solenoid. A regulated 5 volt DC current is provided by a regulator (REG 1), of a type known as 7805, to all counter circuits. Various further features are included, such as reverse voltage protection, noise suppression, failsafe feature security override. The latter is an XY matrix whereby two individuals can provide data to generate an output signal to actuate the solenoids in the event of circuit failure. An on/off switch SW3 (34) is provided for turning off the display when not needed to conserve power. Isolation against reverse polarity of the power source and compensation for failure of a conventional AC power supply is provided.
Thumb wheels 18,20 and 22 provide a voltage output reflective of a specific number from 0 to 9. These thumb wheels, or number generators, permit entry in parallel, rather than serially, of the number of hours to be made. This feature substantially eases and simplifies operation of the timer to an operator. A crystal oscillator, IC10, is a precision crystal oscillator to provide sufficient accuracy to meet the tight time schedules of a bank. The crystal oscillator generates a precise 18641 Hz signal coupled to IC7 via conductor 300. The function of potentiometer POT1, interconnected between pin 9 of IC7 and crystal IC10, is to provide a potential for variable feedback to accommodate differences in range of sensitivity of crystals which are commercially available. With the use of an oscilloscope or like instrument, the input frequency to IC7 can be readily set very accurately irrespective of variations in the crystals that might be used. IC7 includes internal counters that divide by 2 16 to produce a 1.20058 Hz output signal on conductor 302 at pin 3. Conductor 302 applies the output signal to pin 10 of IC8. The output of IC8 is conveyed via conductor 304 from pin 1 of IC8 to pin 3 of IC9. IC9 contains invertor and driver circuits. The output of IC9 appears at pin 2 and is conveyed via conductor 306 to test switch SW1. The output of switch SW1 (202) is conveyed via conductor 308 to pin 14 of IC1. IC1 is an up/down digital counter. The purpose for test switch SW1 (202) is that of accelerating the timer to compress the time of one hour to one second for test purposes; it is not available to an end user. On throwing the switch, the output signal on pin 3 of IC7 is applied directly to pin 14 of IC1 to bypass the countdown by IC8.
To initiate operation of the timer, all counters (IC1, IC2 and IC3) have to be reset to zero. This function is performed by reset switch SW2 (32), which switch may be a double pole, double throw switch. On actuation, the switch will ground each of pins 11 of IC1, IC2 and IC3, which grounding zeros all internal flip flops. Simultaneously, switch SW2 (32) applies 5 volts to pin 11 of IC8 via conductor 311, which pin is normally grounded through the switch, to zero the counter. Simultaneously, 5 volts is applied to pin 12 of IC7 via conductor 312 to reset the crystal circuit; normally, pin 12 is grounded through switch SW2. Accordingly, a simple push upon the reset switch SW2 (32) eliminates resetting of all individual counters and the work load upon a bank employee is substantially reduced.
The three main counters, IC1, IC2 and IC3 are reversible counters. In the configuration employed, each of them counts up. IC1 counts from zero to 10, IC2 provides a decades count and IC3 provides a hundreds count. IC1 generates a binary code from zero to 9 by providing outputs upon pins 2, 3 and 6. When the count of 9 is reached, a carry is provided at pin 13 and an input signal will appear at pin 14 of IC2 via conductor 322. IC2 will provide an output on pins 2, 3 and 6 in the same manner as IC1. On completion of the count, a carry will generate an output at pin 13 which is conveyed to pin 14 of IC3 via conductor 324. Pins 2, 3 and 6 of IC3 will provide an output in the same manner as discussed with respect to IC1. Pins 4 of each of IC1, IC2 and IC3 are interconnected via conductor 326 and with pin 9 of IC9 and with pin 6 of IC6 via conductor 336. A signal on pin 4 will disable counters IC1, IC2 and IC3. Each of pins 7 of IC1, IC2 and IC3 are connected via conductor 330 to each of pins 1 of IC4, IC5 and IC6 to limit the count to zero to 9 instead of zero to 15. On reaching the count of 9, a resetting function is performed. Similarly, conductor 330 interconnects terminal G of each of displays 1, 2 and 3. These displays are also reset.
A 5 volt regulated power is applied to pins 16 of each of ICs 1, 2, and 3. Because these integrated circuits switch very rapidly, approximately at a 20 megacycle rate, voltage spikes may occur. The function of each of capacitors C1 is that of grounding transient voltage spikes. Similarly, the power applied to pin 16 of each of ICs 4, 5 and 6 is smoothed of transient voltage spikes by capacitors C2.
Pin 3 of IC4 is connected to a 5 volt power supply. It serves the function of limiting the count to zero to 9. IC4 provides an output at pin 6 connected via conductor 332 to pin 3 of IC5 to start the count of IC5 to limit the count of IC5 to zero to 9. IC5 provides an output at pin 6 connected to pin 3 of IC6 via conductor 334 to limit the count of IC6 to a count of zero to 9. Pin 6 of IC6 is connected via conductor 336 to conductor 326, the latter being in electrical communication with pins 4 of IC1, IC2 and IC3. With these connections, all three comparators, IC4, IC5 and IC6, will begin their count at zero. Upon obtaining an output at pin 6 of IC6, an output signal is provided which will ultimately result in termination of the timer and opening of the vault door.
The input to comparator IC4 is provided by dial 3 acting through terminals 1, 2, 4 and 8 to provide a desired numeral. A 5 volt power source, acting through current limiting resistors, R1, R2, R4 and R8, interconnects with terminals 1, 2, 4 and 8 of dial 3 and pins 10, 12 13 and 15 of IC5 via conductors 340,342,344 and 346, respectively. Accordingly, a selected numeral of dial 3 will provide an appropriate signal input to comparator IC4. Dial 2 includes a duplicated capability for providing the equivalent of a numerical input to pins 10,12,13 and 15 via conductors 348,350,352 and 354. By design, comparator IC6 is limited to a single numeral, 1, in order for the timer to provide a maximum output of 199 hours. Accordingly, terminal 1 of dial 1 provides an input to pin 10 of comparator IC6 via conductor 356. Power from a 5 volt source is provided via resistor R1. Pins 12,13 and 15 of IC6 are grounded via conductors 358,360 and 362. Accordingly, manipulation of dials 1, 2 and 3 will generate the proper code to correspond with the number of hours to be counted.
Displays 1, 2 and 3 are seven segment displays for displaying the number of hours remaining during a countdown. Terminal A of each of the displays is connected to a five volt power source. Terminals B, C and G of each display control the segments of the seven segment display which is to be lighted. Comparator IC4 provides an output at pin 11 transmitted to terminal B of display 1 via conductor 364. Pin 14 of IC4 provides an output via conductor 366 to terminal C of display 1. Terminal 1 of IC4 provides an output to terminal G of display 1 via conductor 330. It may be noted that conductor 364 is also tied in with pin 2 of IC1, conductor 366 is tied in with pin 6 of IC1 and conductor 330 is tied in with pin 7 of IC1. Similarly, pin 11 of comparator IC5 is connected to terminal B of display 2 and pin 2 of IC2 via conductor 368. Pin 14 of comparator IC5 provides an output to terminal C of display 2 via conductor 370; this conductor is also connected with pin 6 of IC2. Pin 1 of comparator IC5 is connected to pin 7 of IC2 via conductor 330 and to terminal G of display 2 via conductor 372. Pin 11 of comparator IC6 provides an input to terminal B of display 3 via conductor 374; this conductor is also connected to pin 2 of IC2. Pin 14 of comparator IC6 is connected to terminal C of display 3 via conductor 376 and to terminal 6 of IC3. Terminal 1 of comparator IC6 is connected to pin 7 of IC3 via conductor 330 and to terminal G of display 3 via conductor 378. Terminal E of display 1 is interconnected with terminals E of display 2 and 3 via conductor 380. This conductor is grounded through display switch SW3 to energize the respective segments of displays 1, 2 and 3.
Pin K of display 1 is electrically connected to light emitting element 382 identified by the designation "run". It provides a visual indication to an operator that the oscillator is running and that the unit is ready to be actuated. Pin K is connected to pin 4 of IC9 via conductor 384. Pin 4 of IC9 goes high only when crystal oscillator IC7 and counter IC8 are functioning along with IC9.
Pin 6 of IC6 goes high on completion of the previously set time. The output is conveyed via conductor 336 to conductor 386 to solenoid drive circuits TP1 and TP2. Preferably, TP1 and TP2 are very high gain Darlington transistors in order to generate up to 4 amperes to drive solenoids SOL1 and SOL2. Since the two solenoids are not to be operated simultaneously, but sequentially, a timed delay circuit formed by resistor TR and capacitor C attendant transistor TP2 is employed. This provides a 50-100 millisecond timed delay, depending upon the values of TR (normally 1.47K ohms) and capacitor C. Power for the solenoids is provided from +12 volt source through diodes D1, D2 and conductor 388. Current to the collector of transistor TP1 is provided through conductor 388 and conductor 392 via the coil of solenoid SOL1. Current to solenoid SOL2 is provided via conductor 388 and conductor 390 and to the collector of transistor TP2. Transistor TP1 will conduct upon presence of a signal on conductor 394 and transistor TP2 will conduct after the time delay defined by resistor TR and capacitor C. Switch SW4 (100) is ganged with solenoids SOL1 and SOL2 to switch SW4 (100) from the normally closed to the open (grounded) position. Prior to switching, switch SW4 (100) provides an input from conductor 386 to two conductors 396, 398 connected to pins 12 and 14 of, respectively, an IC9. These inputs will terminate further output of IC9. Light emitting element 422, connected intermediate pins 6 and 15 of IC9, is energized upon application of voltage to pins 12 and 14 of IC 9 as a result of actuation of at least one of solenoids SOL1 and SOL2. More specifically, when switch SW4 is in the normally closed (NC) position, both conductors 386 and 398 are at the same potential (low). When the timer reaches its final value and the solenoids are activated, switch SW4 goes to the normally open (NO) position. This grounds conductor 386 and allows voltage to flow to LED 422. Thereby, a visual indication can be provided that at least one solenoid has been energized and the latch of the timer has been unlatched; however, this indicator is optional.
Regulator REG1 is connected to conductor 388 and provides a 5 volt output on conductor 400 which is connected to the various circuit components, as indicated. Capacitor C2 is incorporated to prevent oscillation of regulator REG1. Capacitor C1 decouples the regulator from ICs 1 to 6; it also provides some current smoothing.
Because there is always the possibility of circuit failure due to any number of causes, it is mandatory that operation of solenoids SOL1 and SOL2 be performable without destruction of timer 10. To achieve this end, a matrix M may be employed. This type of matrix is sometimes referred to as an XY matrix. It requires two inputs, one for the X axis and one for the Y axis individually held by different bank security persons. Each of such two persons would energize his/her respective axis. At the point of intersection, a hole would be drilled which would result in application of a voltage on conductors 402, 404 to energize SOL1 and on conductors 406, 408 to energize SOL2.
A battery BAT is connected to +12 volt supply via 3 pole single throw switch SW5. An available alternating current power source provides power to charging network CN. Coupling diodes D3, D4 provide a trickle charge to battery BAT via conductor 410. Switch SW6 (119) is closed on raising of plate 74 (See FIGS. 2, 5A and 5B). Transistor TR20, connected through switch SW6 (119) switch SW5 (36) and conductor 412 to the output of the coupling diodes, provides an indication on conductor 413 that the charging current is functioning. Conductor 413 is connected to terminal K of display 3. An input signal on terminal K energizes light emitting element 414 to signal that DC power is provided. Switch SW7 (118) is closed on raising plate 74 (See FIGS. 2, 5A and 5B). Transistor TR30 is connected to charger CN via switch SW7 (118), switch SW5 (36) and conductor 416. The output of transistor TR30, conveyed via conductor 418 energizes terminal K of display 2. Terminal K activates light emitting element 420 to indicate that AC power is available. Normally open switch SW6 (119) may be ganged with the display switch, SW3 (34), to energize light emitting element 414 only when the display is lighted. The threshold voltage at the base of transistor TR20 is 0.6 volts, whereby an indication is not provided unless at least a threshold voltage of 0.6 volts is provided at the base electrode of transistor TR20 and a threshold voltage of 0.7 is provided at the base electrode of transistor TR30. Accordingly, when these voltages are exceeded by the battery, or the AC power, respectively, the respective light emitting elements are turned on. (Switch SW5 (36) is also termed the master switch, switch 36. In some installations, master switch SW5 may be elected not to be used in accordance with bank policy to preclude the possibility of an employee inadvertently leaving the switch in the off position.) It may be noted that battery BAT is within the bank vault; therefore, the timer cannot be turned off or otherwise be disconnected without access through the bank vault door.
Although a failure mode is rare for the integrated circuits used in the above described and illustrated timer, inadvertent opening of the bank vault due to a failure of a circuit component would be intolerable and unacceptable. The timer described above precludes a failure of any of the components from causing an unintentional opening of the vault door. This result is assured since a failure of a component will result in, at worst case, a low level signal on any particular conductor or pin. To confirm this conclusion, each of the components will be reviewed with respect to the effect resulting from failure of the component. A failure of the crystal, IC10, or IC7 will curtail further pulses on conductor 307 and pin 3. Without generated pulses, the timer will stop. A failure of IC8 would prevent an output on pin 1 of IC8 and conductor 304 and no further action would occur. Since IC9 is simply an invertor, failure would result in no further action. Failure of any of IC1, IC2 or IC3 would cease propagation of pulses and the timer would stop. A failure of IC4 or IC5 would preclude a voltage or pulse on conductors 332 and 334 and the timing function would cease. Should IC 6 fail, pins 6 and 7 would not provide a high output on conductor 320 and Darlington transistors TP1 and TP2 would not be triggered. Since the twelve inputs on comparators IC4, IC5 and IC6 have to agree with the thumb wheel switches to permit opening of the vault, such agreement cannot occur if any component of the timer fails. Should there be a component failure, the manually operated X-Y matrix would have to be implemented.
While the principles of the invention have now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, elements, materials and components used in the practice of the invention which are particularly adapted for specific environments and operating requirements without departing from those principles.
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A low current drain timer for bank vaults is easily settable to limit opening of the vault to a predetermined time, irrespective of the time of closing the vault. Three thumb wheels having corresponding indicia are set to designate the elapsed time necessary for reopening. A timer is activated by a reset switch and the manual repositioning of a mechanical latch, which latch permits later closure of a vault door. Either of sequentially operating solenoids at the lapsed time permit opening of the vault door. A backup battery power source renders the timer unaffected by failure of a conventional electrical power source.
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FIELD OF THE INVENTION
The present invention relates to database systems, and more particularly to confidential data encryption in database systems.
BACKGROUND OF THE INVENTION
Just as computers have become more and more prevalent in everyday life, networks of linked computers have become important in distributing information amongst computer users. Many computer systems are organized according to a client/server metaphor. Generally, in client/server computing, end users are each provided with a desktop computer or terminal known as a “client.” The clients are connected using a network to another computer known as a “server”, because its general function is to serve or fulfill requests submitted by clients. Application programs running on the clients prepare requests and transmit them to the server over the network. A ‘network’ of computers can be any number of computers that are able to exchange information with one another. The computers may be arranged in any configuration and may be located in the same room or in different countries, so long as there is some way to connect them together (for example, by telephone lines or other communication systems) so they can exchange information. Just as computers may be connected together to make up a network, networks may also be connected together through tools known as bridges and gateways. These tools allow a computer in one network to exchange information with a computer in another network.
Of particular interest in today's computing environment are relational database applications. Relational DataBase Management System (RDBMS) software using a Structured Query Language (SQL) interface is well known in the art. The SQL interface has evolved into a standard language for RDBMS software and has been adopted as such by both the American Nationals Standard Organization (ANSI) and the International Standards Organization (ISO).
In RDBMS software, all data is externally structured into tables. The SQL interface allows users to formulate relational operations on the tables either interactively, in batch files, or embedded in host languages such as C, COBOL, etc. Operators are provided in SQL that allow the user to manipulate the data, wherein each operator operates on either one or two tables and produces a new table as a result. The power of SQL lies in its ability to link information from multiple tables or views together to perform complex sets of procedures with a single statement.
The power of being able to gather, store, and relate information in database systems and then operate on that information through SQL allows for an almost limitless range of applications for such technology. Together with computer networks, including the Internet, incredible opportunities exist for people and businesses to communicate and to conduct commerce. Concerns arise with these opportunities, particularly with regard to ensuring confidentiality of personal information, sensitive communications, and financial data.
For example, users sometimes are required to input personal information, such as credit card information, for processing within a website. While security techniques may be used during the transmission of the data, within the database receiving and storing the information, the information remains accessible to the database administrator (DBA). A DBA refers to an individual who is responsible for the design, development, operation, safeguarding, maintenance, and use of a database. Unfortunately, the accessibility of the confidential, personal information of a user creates an opportunity for intruders/malicious DBAs to misuse the information.
Accordingly, a need exists for a technique that provides users with a straightforward and flexible manner of protecting confidential information within a database. The present invention addresses such a need.
SUMMARY OF THE INVENTION
The present invention provides aspects for integrating encryption functionality into a database system. The aspects include providing at least two functions to support data encryption in a database system. The at least two functions are utilized within structured query language statements to preserve confidentiality of user-specified data in the database system.
Through the aspects of the present invention, users have better assurance that data private to a database application remains inaccessible to others, such as database administrators. Further, the provision of the encryption functionality of the present invention in an integrated manner with SQL creates a substantially unlimited range of database environments within which the present invention may be used. These and other advantages of the aspects of the present invention will be more fully understood in conjunction with the following detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an overall block diagram of a computer system network in accordance with the present invention.
FIG. 2 illustrates a diagram representation of a database system environment in accordance with the present invention.
FIG. 3 illustrates a block flow diagram for achieving the protection of confidential data in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to protection of confidential data within a database by a user. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Thus, the present invention is not intended to be limited to the embodiment shown, but is to be accorded the widest scope consistent with the principles and features is described herein.
As shown in FIG. 1 , a plurality of computer systems 1 a , 1 b , 1 c are interconnected via a network 2 (which could be the public Internet or a private intra-corporate Intranet or wide area network). It should be appreciated that although FIG. 1 illustrates a network of computer systems, this is meant as exemplary and not restrictive of the type of environment suitable for the aspects of the present invention. Thus, the aspects may also be provided within a single computing system environment. Accordingly, one ( 1 c ) of the computer systems is shown expanded for further illustration.
Computer system 1 c has a processor 13 for controlling the overall operation of the computer system 1 c , a high speed cache memory 12 , a long-term storage device 14 (e.g., hard disk drive), and a database management system 15 , e.g., an RDBMS system, such as DB 2 .
In accordance with the present invention, functions are provided that achieve privacy and user control of access to data in the database system 15 , so that only users with the proper access and password can view the data. These functions are integrated into the database system 15 to allow access via SQL statements executed in the database system 15 . The integration of the functionality into the database system 15 with the present invention occurs through a straightforward approach that can be utilized as desired with any client application of the database, as described in more detail hereinbelow.
Referring to the diagrams of FIG. 2 and FIG. 3 , functions, including encrypt function 20 and decrypt function 22 , achieve the protection of confidential data in the database system 15 . The functions 20 and 22 are suitably provided as user-defined functions in the database system 15 (step 30 ). A user-defined function (UDF) generally refers to a function that is defined to the database management system and can be referenced thereafter in SQL queries. Alternatively, the functions 20 and 22 may be defined through standard techniques as built-in functions within a database system. The functions 20 and 22 can then be utilized via SQL to ensure data confidentiality in the database system 15 (step 32 ), i.e., the encrypt function 20 is processed by SQL processing 24 to generate the encrypted form of data as the data is inserted or updated from a client application 26 in the database system 15 , while SQL processing 24 of the decrypt function 22 generates the decrypted form of the data during selects from the database system 15 by the client application 24 . Thus, each item of data can be uniquely encrypted. Alternatively, a single key/password can be used to encrypt an entire column of data in the database system 15 .
By way of example, suppose a table exists for social security numbers (SSN) of employees (EMP) of a company in the database system 15 . The following example SQL statements illustrate the use of the encrypt and decrypt functions and encryption password in accordance with the present invention to ensure confidentiality with such a table.
INSERT INTO EMP (SSN) VALUES ENCRYPT (‘289-46-8832’, ‘GEORGE’); SELECT DECRYPT (SSN, ‘GEORGE’) FROM EMP;
In this example, the SELECT statement returns the value “289-46-8832.”
In a further embodiment, the encrypt function 20 may encrypt a password hint, as well. A password hint refers to a phrase that assists data owners in remembering their passwords. With the ability to encapsulate password hints, another function, GETHINT, can be defined that returns an encapsulated password hint.
When the inclusion of a hint for the password is desired, such as the use of the hint “WASHINGTON” for remembering the password of “GEORGE”, the insert statement for the example becomes:
INSERT INTO EMP (SSN) VALUES ENCRYPT (‘289-46-8832’, ‘GEORGE’, ‘WASHINGTON’);
A select statement to get the hint:
SELECT GETHINT (SSN) FROM EMP; returns the value “WASHINGTON.”
As demonstrated by the example, the encrypt function 20 and decrypt function 22 preferably follow the basic formats:
ENCRYPT (data-string-expression, password-string-expression) returns varchar DECRYPT (data-string-expression, password-string-expression) returns varchar or ENCRYPT (data-string-expression (clob), password-string-expression) returns clob DECRYPT (data-string-expression (clob), password-string-expression) returns clob.
The format for the encrypt function 20 with a password hint preferably follows the format:
ENCRYPT (data-string-expression, password-string expression, hint-string expression) returns varchar or ENCRYPT (data-string-expression (clob), password-string expression, hint-string-expression) returns clob
And, for the GETHINT function:
GETHINT (data-string-expression) returns varchar or GETHINT (data-string-expression (clob)) returns varchar
In the foregoing formats, varchar suitably refers to variable-length character data with a length of ‘n’ characters, and clob refers to character large object, i.e., a sequence of characters (single-byte, multi-byte, or both) where the length can be up to 2 gigabytes that can be used to store large text objects, as is well understood in the art. In an exemplary embodiment, the password valid length is 6 to 128 and the hint valid length is 0 to 32. The provision of the password may be done explicitly, or in alternate embodiment, for systems utilizing a login context that requires a user to enter password, the password entered could be utilized as an implicit provision of the encryption key password for the encrypt functions.
With the encryption techniques using a password as an encryption key, the present invention provides a straightforward and flexible technique to protect confidential data in a database in a manner that allows integration with well-established, non-proprietary SQL techniques. Accordingly, users have better assurance that data private to a database application remains inaccessible to others, such as database administrators. Further, the provision of the encryption functionality of the present invention in an integrated manner with SQL creates a substantially unlimited range of database environments within which the present invention may be used.
Although the present invention has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the present invention. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.
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Aspects for integrating encryption functionality into a database system are described. The aspects include providing at least two functions to support data encryption in a database system. The at least two functions are utilized within structured query language statements to preserve confidentiality of user-specified data in the database system.
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FIELD OF THE INVENTION
[0001] The present invention relates to a system for preparing antimicrobial fabrics, coated with metal oxide nanoparticles by a novel sonochemical method.
BACKGROUND OF THE INVENTION
[0002] Antibacterial fabrics are widely used for production of outdoor clothes, under-wear, bed-linen, and bandages. Antimicrobial resistance is very important in textile materials, having effects amongst others on comfort for the wearer. The deposition of metal oxides known to possess antimicrobial activity, namely ZnO, MgO and CuO, can significantly extent the applications of textile fabrics and prolong the period of their use.
[0003] Zinc oxide has been recognized as a mild antimicrobial agent, non toxic wound healing agent, and sunscreen agent. Because it reflects both UVA and UVB rays, zinc oxide can be used in ointments, creams and lotions to protect against sunburn and other damage to the skin caused by ultraviolet lights [Godfrey H. R. Alternative Therapy Health Medicine, 7 (2001) 49]. At the same time ZnO is an inorganic oxide stable against temperatures encountered in normal textile use, contributing to its long functional lifetime without color change or oxidation. The antibacterial properties of MgO and CuO nanoparticles were also demonstrated [ Controllable preparation of Nano-MgO and investigation of its bactericidal properties . Huang L., Li D. Q, Lin Y. J., Wei M., Evans D. G., Duan X. L. Inorganic Biochemistry, 99 (2005) 986, and Antibacterial Vermiculite Nano-Material . Li B., Yu S., Hwang J. Y., Shi S. Journal of Minerals & Materials Characterization & Engineering, 1 (2002) 61].
[0004] An antimicrobial formulation containing ZnO powder, binding agent, and dispersing agent was used to protect cotton and cotton-polyester fabrics [“Microbial Detection, Surface Morphology, and Thermal Stability of Cotton and Cotton/Polyester Fabrics Treated with Antimicrobial Formulations by a Radiation Method”. Zohby M. H., Kareem H. A., El-Naggar A. M., Hassan, M. S., J. Appl. Polym. Sci. 89 (2003) 2604] This formulation was applied to fabrics under high energy radiation of Co-60 γ or electron beam irradiation and then subjected for fixation by thermal treatment. A superior antimicrobial finish was achieved with cotton fabrics containing 2 wt % ZnO and with cotton-polyester fabrics containing 1 wt % ZnO. The particle size of ZnO in these samples according to SEM measurement was 3-5 μm. In spite of good antimicrobial activity, the disadvantages of this method are the use of additional binding and dispersing agent, and requirements of high energy radiation and an additional stage of thermal curing. It was also reported that ZnO-soluble starch nanocomposite was impregnated onto cotton fabrics to impart antibacterial and UV-protection functions with ZnO concentration 0.6-0.8 wt % [ Functional finishing of cotton fabrics using zinc oxide-soluble starch nanocomposites . Vigneshwaran N., Kumar S., Kathe A. A., Varadarajan P., Prasad V., Nanotechnology 17 (2006) 5087]. The particle size of ZnO in zinc oxide-starch composition was reported as 38 nm. However, in this work the special stabilizing agent, namely, acrylic binder is used which should undergo the additional stage of polymerization at 140° C.
[0005] Hence, an improved method of dispersion metal oxide nanoparticles onto textiles is still a long felt need.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] In order to understand the invention and to see how it may be implemented in practice, a plurality of embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which
[0007] FIG. 1 presents an XRD pattern indicating hexagonal phase of ZnO matching PDF file: 89-7102.
[0008] FIG. 2A-C presents HR SEM images of the fabric coated with ZnO: a—before coating, b—after coating, c—high magnification of figure b.
[0009] FIG. 3A , B present images of fabric coated with ZnO: a—before coating, b—after coating.
[0010] FIG. 4A , B presents a Comparing hydroxyl radicals generated from microscale and nanoscale ZnO, using DMPO as a spin-trapping agent and Theoretical (Computer) simulation of the ESR spectrum of hydroxyl radicals.
[0011] FIG. 5 presents the amount of the hydroxyl radicals in a medium containing both ZnO and bacteria.
SUMMARY OF THE INVENTION
[0012] The present invention comprises a system and method for sonochemical dispersion of metal oxide nanoparticles onto textiles.
[0013] It is within the core of the present invention to provide a method for ultrasonic impregnation of textiles with metal oxide nanoparticles consisting of steps of:
a. preparing a water-ethanol solution; b. adding M(Ac) 2 to said solution, forming a mixture; c. immersing said textiles in said mixture; d. adjusting the pH of said mixture to basic pH by means of addition of aqueous ammonia; e. purging said mixture to remove traces of CO 2 /air; f. irradiating said mixture with a high intensity ultrasonic power; g. washing said textile with water to remove traces of ammonia; h. further washing said textile with ethanol, and drying in air.
thereby producing a textile—metal oxide composite containing homogeneously impregnated metal oxide nanoparticles, without use of electromagnetic radiation.
[0022] It is further within provision of the invention to provide the aforementioned method where said water-ethanol solution is in a ratio of approximately 1:9.
[0023] It is further within provision of the invention to provide the aforementioned method where M(Ac) 2 is added in a concentration of between 0.002 and 0.02 M.
[0024] It is further within provision of the invention to provide the aforementioned method where M is selected from a group consisting of metals Zn, Mg, Cu.
[0025] It is further within provision of the invention to provide the aforementioned method where said basic pH is approximately 8.
[0026] It is further within provision of the invention to provide the aforementioned method where said step of purging is carried out with argon for 1 hour.
[0027] It is further within provision of the invention to provide the aforementioned method where said step of irradiating said mixture is carried out for 1 hour
[0028] It is further within provision of the invention to provide the aforementioned method where said step of irradiating said mixture is carried out by means of an ultrasonic horn
[0029] It is further within provision of the invention to provide the aforementioned method where said step of irradiating said mixture is carried out using ultrasonic waves at a frequency of approximately 20 kHz.
[0030] It is further within provision of the invention to provide the aforementioned method where said step of irradiating said mixture is carried out using ultrasonic waves at a power of approximately 1.5 kW
[0031] It is further within provision of the invention to provide the aforementioned method where said step of irradiating said mixture is carried out under a flow of argon
[0032] It is further within provision of the invention to provide the aforementioned method where said step of irradiating said mixture is carried out at approximately 30° C.
[0033] It is further within provision of the invention to provide the aforementioned method where said textile composite contains between 0.1 wt % and 10 wt % of metal oxide (MO).
[0034] It is further within provision of the invention to provide the aforementioned method where MO nanocrystals are between 10 nm and 1000 nm in diameter. It is further within provision of the invention to provide textiles imparted with bacteriostatic properties by means of ultrasonic irradiation of said textiles in an aqueous metal oxide mixture, thereby attaining uniform impregnation of said textiles with metal oxide nanoparticles.
[0035] According to another embodiment of the present invention, when commercial MO nanoparticles are introduced in the sonication mixture or MO nanoparticles commercially available (prepared by another method and not sonochemically). The ultrasound can still be used for “throwing stones” at the fabric surface, and good antibacterial properties are obtained.
[0036] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0037] The following description is provided, alongside all chapters of the present invention, so as to enable any person skilled in the art to make use of said invention and sets forth the best modes contemplated by the inventor of carrying out this invention. Various modifications, however, will remain apparent to those skilled in the art, since the generic principles of the present invention have been defined specifically to provide a means and method for providing a wood-resin composite.
[0038] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. However, those skilled in the art will understand that such embodiments may be practiced without these specific details. Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention.
[0039] The term ‘sonochemical irradiation’ hereinafter refers to exposure to sonic power, generally in the ultrasonic range of frequencies.
[0040] The term ‘sonochemistry’ refers to the study or use of sonochemical irradiation.
[0041] The term ‘nanoparticles’ hereinafter refers to particles of size ranging from about 10 micrometers to about 10 nanometers.
[0042] The term ‘oxide’ hereinafter refers to any inorganic oxide such as ZnO, MgO, CuO, and the like. In the following when ZnO is used specifically, it is used in exemplary fashion and can be replaced by any oxide as will be obvious to one skilled in the art.
[0043] The term ‘plurality’ refers hereinafter to any positive integer e.g, 1,5, or 10.
[0044] It is within provision of the instant invention to offer a new process for preparation of textiles impregnated with nanometric oxide particles. The sonochemical method is applied for the deposition of ZnO nanocrystals on textile materials to impart them excellent antimicrobial activity. A comparison of the suggested ZnO-textile nanocomposite shows a clear advantage of the ultrasound radiation over all other available methods as will be described below.
[0045] We have demonstrated that sonochemical irradiation is a suitable method for synthesis of nanomaterials, and their deposition/insertion on/into ceramic and polymer supports. One of the many advantages demonstrated for sonochemistry is that a homogeneous dispersion of the nanoparticles on the surface of the substrate is achieved in one step. In this step the nanoparticles of the desired products are formed and accelerated onto/into the surface or body of the polymer or ceramics via microjets or shock waves that are created when a sonochemically produced bubble collapses near a solid's surface. The current patent is based on the work done by the inventors—see The Preparation of Metal-Polymer Composite Materials using Ultrasound Radiation , S. Wizel, R. Prozorov, Y. Cohen, D. Aurbach, S. Margel, A. Gedanken. J. Mater. Res. 13,(1998) 211; Preparation of amorphous magnetite nanoparticles embedded in polyvinylalcohol using ultrasound radiation“ . R. Vijaykumar, Y. Mastai, A. Gedanken, Y. S. Cohen, Yair Cohen, D. Aurbach, J. Mater. Chem. 10 (2000) 1125; Sonochemical Deposition of Silver Nanoparticles on Silica Spheres V. G. Pol, D. Srivastava, O. Palchik, V. Palchik, M. A. Slifkin, A. M. Weiss. A. Gedanken, Langmuir, 18, (2002) 3352; Synthesis and Characterization of Zinc Oxide-PVA Nanocomposite by Ultrasound Irradiation and the Effect of the Crystal Growth of the Zinc Oxide” R. Vijayakumar, R. Elgamiel, O. Palchik, A. Gedanken, J. Crystal Growth and Design, 250 (2003) 409; Sonochemical Deposition of Silver Nanoparticles on Wool Fibers . L. Hadad, N. Perkas, Y. Gofer, J. Calderon-Moreno, A. Ghule, A. Gedanken,. J. Appl. Polym. Sci. 104 (2007)1732. These publications studied the deposition of large variety of nanoparticles on different kinds of substrates. The deposition was conducted either with materials that were dissolved in the irradiated solution or dispersed (not dissolved) in the solution.
[0046] The use of the sonochemical method helps to achieve all the principal requirements of the antimicrobial textile coated with nanomaterials: small particle size, regular shape, and homogeneous distribution of ZnO nanoparticles on the fabrics. Amongst the advantages of using ultrasound over other methods is that ultrasonic shockwaves effectively blast the oxide nanocrystals onto a fabric's surface at such speed that it causes local melting of the substrate, guaranteeing firm embedding of the nanocrystals within the textile fibers. Textiles sonochemically impregnated with ZnO displays outstanding antimicrobial activity in the case of both gram-positive and gram-negative bacteria.
[0047] An experimental procedure was developed as follows for testing and evaluation purposes. Other routes will be obvious to one skilled in the art, and the following is provided only by way of example.
PREPARATION PROCEDURE
[0000]
1. A textile sample (such as a cotton square of about 100 cm 2 ) is placed in a 0.002-0.02 M solution of M(Ac) 2 , (where M stands for metals Zn, Mg, Cu; and Ac stands for acetate ion) in a water:ethanol (1:9) solution.
2. The pH is adjusted to 8 with an aqueous solution of ammonia.
3. The reaction mixture is then purged with argon for 1 hour in order to remove traces of CO 2 /air.
4. The solution is irradiated for 1 hour with a high intensity ultrasonic horn (Ti-horn, 20 kHz, 1.5 kW at 70% efficiency) under a flow of argon at 30° C.
5. The textile is washed thoroughly with water to remove traces of ammonia, then further washed with ethanol and dried in air.
[0053] It is also within provision of the invention to prepare the metal solutions as above using metal nitrates or other salts, as will be obvious to one skilled in the art.
[0054] As will also be obvious to one skilled in the art, the coating process can be accomplished without producing nanoparticles ‘in house’, by adding nanoparticles obtained by some other means to solution and ultrasonically treating as above in steps 2-5. The yield (amount of nanoparticles on the textile) in this case would be lower but enough to get antibacterial properties.
RESULTS
[0055] A sample coated by the above process with MO was tested for its antibacterial properties with gram-positive ( S. aureusa ) and gram-negative ( E. coli ) cultures. Antibacterial effects were shown in treated textiles even at a coating concentration of less than 1%, for all metal oxides mentioned above (Zn, Mg, Cu). We observed 98% reduction of the two strains of the bacteria after 1 hour.
[0056] Our experiments have also demonstrated that antibacterial treatment of ZnO coated bandages can increase the sensitivity of bacteria cells to two kinds of antibiotics; a 43% additional reduction in colonies was detected for Chloramphenicol due to the metal oxide and 34% for Ampicillin. The concentrations of antibiotics used in these experiments were much lower than those normally expected to cause any significant change in the bacteria growth. Thus, our results indicate a cooperative or synergic effect of metal oxide textile impregnation and antibiotic treatment.
[0057] The textile composite so produced contains on the order of 1 wt % of metal oxide (MO). The MO nanocrystals are of size ˜150 nm, and are homogeneously distributed on the surfaces of the textile fibers.
[0058] The metal oxide concentration in the fabrics prepared as above can be varied in the range 0.5-10.0%.
[0059] We now refer to FIG. 1 which displays XRD patterns of fabrics coated with zinc oxide, confirming the presence of ZnO nanocrystals. The homogeneous distribution of ZnO nanocrystals on the textile fibers was demonstrated in high-resolution SEM micrographs ( FIG. 2 ). After sonochemical deposition of ZnO nanocrystals on the fabrics the color and texture of the material didn't change ( FIG. 3 ).
[0060] As is known in the art, the existence of free radicals can aid in destruction of bacteria. In our investigation, the generation of both active oxygen species (O 2 − and OH.) from the ZnO powder was demonstrated using ESR measurements. Moreover, we found that at the nanoscale regime of ZnO particle size, the amount of the generated OH. was considerably higher than that of the microscale size, probably due to a higher specific surface area of the smaller particles ( FIG. 4 ). Similar spectra were obtained when a piece of ZnO-cotton coated bandage was introduced in the ESR tube. These results are in good agreement with the measured influence of particle size on the antibacterial activity of ZnO powders, as it was found that the antibacterial activity of ZnO increased with decreasing particle size. This is supported by the following table of results measuring bacteria reduction for two bacteria types ( E. coli and S. aureusa ) after various treatment times, for different particle sizes of ZnO crystallites. Sample ZnO-1 has diameter ˜8 nm, sample ZnO-2 has diameter ˜275 nm, and sample ZnO-3 has diameter ˜600 nm.
[0000]
TABLE 1
bacteria population reduction for different grainsizes and treatment
times.
E. coli
S. aureus
Duration of
% Reduction
% Reduction
Sample
treatment [h]
[CFU mL −1 ]
N/N 0
in viability
[CFU mL −1 ]
N/N 0
in viability
ZnO-1
0
6.5 × 10 7
1
0
1.2 × 10 7
1
0
1
5.2 × 10 6
8.0 × 10 −2
92
3.5 × 10 6
2.9 × 10 −1
21
2
6.5 × 10 5
1.0 × 10 −2
99
2.0 × 10 6
1.7 × 10 −1
83
3
1.3 × 10 3
2.0 × 10 −3
99.8
2.4 × 10 5
2.0 × 10 −2
98
ZnO-2
0
6.5 × 10 7
1
0
1.2 × 10 7
1
0
1
10 × 10 7
1.6 × 10 −1
84
6.4 × 10 6
5.3 × 10 −1
47
2
3.3 × 10 6
5.1 × 10 −2
95
4.1× 10 6
3.4 × 10 −1
66
3
3.3 × 10 5
2.0 × 10 −3
99.5
1.3 × 10 6
1.1 × 10 −1
89
ZnO-3
0
6.5 × 10 7
1
0
1.2 × 10 −7
1
0
1
2.0 × 10 7
3.1 × 10 −1
69
1.0 × 10 7
8.7 × 10 −1
13
2
1.69 × 10 7
2.6 × 10 −1
74
8.2 × 10 6
5.8 × 10 −1
42
3
8.5 × 10 6
21.3 × 10 −1
87
3.8 × 10 6
3.2 × 10 −1
68
[0061] As is clear from the table above, the bacteria populations are reduced with greater exposure time and smaller ZnO grain size. The above explanation for these results is further substantiated in FIG. 6 which presents ESR hydroxyl radical spectra of water suspensions with different ZnO samples, showing clearly that as the grainsize decreases the hydroxyl signal increases.
[0062] The textiles sonochemically impregnated with ZnO demonstrate high stability; the amount of ZnO remaining in the textile after 50 washing cycles remains constant. The stability of nanoparticles on the fabric was measured after 50 washing cycles by both TEM measurements, and titrating the fabric with EDTA to determine the amount of ZnO.
[0063] In another experiment, we measured the amount of the hydroxyl radicals in a medium containing both ZnO and bacteria ( e.coli and s.aureusa in saline). An enhancement of the amount of hydroxyl radicals could be detected comparing to samples without the bacteria ( FIG. 5 ). We assume that this enhancement comes from an oxidative stress of the bacteria in a medium containing the ZnO.
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We disclose a system for preparing antimicrobial fabrics, coated with metal oxide nanoparticles by means of a novel sonochemical method. These antibacterial fabrics are widely used for production of outdoor clothes, under-wear, bed-linen, bandages, etc. The deposition of metal oxides known to possess antimicrobial activity, namely ZnO, MgO and CuO, can significantly extent the applications of textile fabrics and prolong the period of their use. By means of the novel sonochemical method disclosed here, uniform deposition of metal oxide nanoparticles is achieved simply.
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[0001] This applications claims priority from U.S. provisional application Serial No. 60/214,685 filed Jun. 27, 2000, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a portable luggage carrier, and more particularly, to a carrier comprising an exercise means attached to and in cooperation with the carrier. The carrier comprises, in addition to the exercise means, a support member having pivotably attached thereto a fold out luggage supporting member having collapsible wheel means attached to the luggage supporting member by means of a telescoping handle means affixed to the support.
[0004] 2. Brief Description of the Prior Art
[0005] This invention relates to a portable luggage carrier, such as for example a carrier for such loads as suitcases, golf bags, etc. Such carriers have been provided in the past but heretofore there has not been such a carrier which contains or is associated with an exercise means to provide a source of exercise when the carrier is not supporting luggage.
SUMMARY OF THE INVENTION
[0006] This invention relates to a portable luggage carrier, and more particularly to such a carrier having an exercise means associated or incorporated therewith. The carrier comprises a support member for supporting the luggage, a fold out platform means connected to the support member for holding the luggage having a collapsible wheel means affixed to the support means in association with a handle means affixed to the support member, and an exercise means attached to the support means.
BRIEF DESCRIPTION OF THE DRAWING
[0007] [0007]FIG. 1 is a perspective view of a portable luggage carrier of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0008] Referring to FIG. 1 a luggage carrier 30 is shown according to the invention. As used herein the term “luggage” is not meant to be limited to a case for carrying clothes, but is meant to include all types of suitcases, boxes, golf bags, athletic bags and the like. The carrier 30 is utilized or destined for carrying luggage (not shown), e.g. a suitcase, a golf bag, boxes, etc.
[0009] The collapsible carrier 30 has a support member or frame 41 having a first leg 42 and a second leg 43 and adjoining cross arm 44 affixed to legs 42 and 43 . Affixed to the cross arm 44 is a pair of triangular braces 46 and 47 for supporting the cross arm 44 and legs 42 and 43 .
[0010] A fold out platform device 48 is pivotably attached to the support member 41 for holding the luggage (not shown) when not in use for exercising. The platform means 48 has support legs 49 and 51 conventionally attached thereto, e.g. welded, bolted, or integrally formed as part of platform means 48 , at each front corner thereof for supporting the carrier 30 when it is loaded with the luggage it is intended to carry. The support legs 49 , 51 may be fabricated from the same material as the platform 48 , which may be plastic or a metal, or may differ from platform 48 and attached to platform 48 by any conventional means, e.g. by bolting, welding, etc.
[0011] Platform means 48 is pivotably attached to the frame 41 by any conventional means. For illustrative purposes only, such pivotable attachment can be carried out as illustrated in U.S. Pat. No. 4,248,453, incorporated hereinto by reference in its entirety. In particular as illustrated in FIG. 1, the fold out platform device 48 is provided with a pair of hinge members 53 and 54 integrally formed therein, which are capable of being rotated about the cross arm 44 when it is desired that platform means 48 is to remain in an extended position perpendicular to the cross arm 44 . The arm 44 is internally threaded with a plurality of threaded openings 56 destined to receive a plurality of securing rods 57 destined to pass through mating holes 58 contained in the binges 53 and 54 . One end of the rod 57 is matingly threaded for screwing into openings 56 to secure the platform means 48 so that it does not rotate if desired. The type of rotational and attachment means is not critical and as indicated any such means known in the art can be employed.
[0012] The platform means 48 has a plurality of tension springs which are interchangeable with one another. The tension springs are illustrated in FIG. 1 as spring 59 , 61 and 62 . The springs 59 , 61 and 62 are releasably attached to the bottom 63 of the platform means 48 along its horizontal axis by any conventional suitable means known in the art, e.g. bolting, threaded security pins, etc. Typically, the tension springs are attached by means of bolting.
[0013] The tension springs 59 , 61 and 62 are of different tensions and are interchangeable with one another, i.e. a higher tension spring 59 can be removed from the platform means 48 and interchanged with a removed lower tension spring 62 or a removed intermediate tension spring 61 , as desired, to change the tension for the lifting and rotation of platform means 48 during the destined exercise operation, utilizing reversible shock cords, illustrated in FIG. 1 as having numeral 64 .
[0014] The shock cords 64 are intended to provide various pulling exercises using the platform means 48 at a selected tension, e.g. high, medium, low, by adjusting the springs 59 , 61 , 62 . In this regard, in operation, the spring closest to the rear end 66 of the platform means 48 , when provided with the highest tension spring, illustrated as spring 59 , will provide the highest level of exercise. The shock cords 64 have a loop 67 which is releasably connected to the front end 69 of the platform 48 , utilizing any conventional means, e.g. a loop/link releasable attachment mechanism as illustrated in U.S. Pat. No. 4,373,716, which is incorporated by reference hereinto in its entirety.
[0015] Provided in the front end 69 of the platform means 48 is a crunch bar 71 . The crunch bar 71 is destined to provide support for the exerciser's legs (not shown) when the carrier is used horizontally in an exercise mode. In this regard, also provided on the supporting frame 41 of the carrier 30 is a lockable rowing-type seat 72 of conventional design fabricated from metal, plastic, etc. The seat 72 is supported on the legs 42 and 43 and extends perpendicularly thereto and is slideable therealong when the carrier is 30 in a horizontal exercise mode. The seat 72 is slideable along legs 42 and 43 in any conventional manner. Typically a channel (not shown) is fabricated in each leg 42 , 43 and an appendage, e.g. a rod, etc. (not shown) extends from, the sides 73 of the seat 72 into each channel (not shown) and traverses the length of each such channel a calculated, predetermined distance.
[0016] The seat 72 is affixed to each leg 42 , 43 whereby it lies flat when the carrier 30 is in its carrying or supporting mode or when the carrier is in a vertical exercise mode. The seat 72 , as previously indicated, can be rotated whereby it extends away from the legs 42 , 43 , typically at a right angle from legs 42 and 43 and is locked, by an conventional means, e.g. threaded rods, etc., in such a position thereby enabling a person who is exercising to sit on the seat 72 on the support 41 , when it is in a vertical position. The rotation of the seat 72 can be accomplished by any conventional means, e.g. a hinge mechanism with locking bolts, etc.
[0017] Affixed to and connecting legs 42 and 43 is an axle (not shown) which rotatably supports a pair of wheels 74 and 76 for both rolling the carrier 30 when carrying a load (not shown) and increasing the stability of the carrier 30 . The wheels 74 , 76 are preferably made of plastic, however, any suitable material can be used, such as for example a metal, wood, rubber, etc. Once the wheels 74 , 76 are put on the axle (not shown) end caps 77 and 78 are force fitted onto the axle (not shown) to keep the wheels 74 , 76 thereon. Alternatively, any conventional retaining means can be employed.
[0018] A telescoping handle means 79 is affixed to the support or frame 41 . The handle means 79 has telescoping sections 81 and 82 which pass into legs 42 and 43 and are releasably locked therein. The handle means 79 is not critical and can be of any conventional type. In this regard reference is made to U.S. Pat. Nos. 3,998,476 and 4,248,453, which describe such typical handle means which have telescoping tube assemblies which are moveable between extended and retracted positions. The disclosures of these two patents are incorporated by reference hereinto in their entirety.
[0019] As illustrated in FIG. 1, the shock cords 64 are attached to two loops 83 and 84 , e.g. by means of hooks, which are removably attached to the top bar 86 of the handle means 79 . The top bar 86 is removably affixed to the handle means 79 and when so removed, in the exercise mode, of the carrier 30 , with cords 64 attached thereto are used to pull up and down the tensioned platform means 48 , in a similar exercise fashion illustrated in U.S. Pat. No. 4,373,716, incorporated by reference hereinto in its entirety. Additionally, it is to be noted that the cords 64 , can be extended over the bar 86 to the opposite side of the carrier 30 when the carrier 30 is used in an exercise mode.
[0020] It is again to be noted that the carrier 30 can be used in a horizontal plane i.e. lying down, and in a vertical plane, i.e. erect, as when carrying a load when not in the exercise mode.
[0021] In an alternative embodiment, a carry-on luggage bag suitable for storage in the overhead compartment of an airplane can be employed. Typically, these luggage bags have a wheel means and a telescoping handle means similar to that as previously described in FIG. 1 for carrier 30 . Additionally the platform means 48 , shock cords 64 and their attachment can be configured and fixed in the bottom of such luggage bag covered over by a masking film or base upon which the traveler's clothes, toiletries, etc. are placed when travelling. In an exercise mode the carry-on luggage with its counterpart platform means 48 and shock cords 64 can be employed as previously described.
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This invention relates to a portable luggage carrier, and, more particularly, to such a carrier having an exercise means associated therewith. The portable carrier comprises a support member or means for supporting the luggage. A fold out platform means connected to the support means for holding the luggage is provided and the carrier has a collapsible wheel means affixed to the support means in association with a handle means affixed to the support member.
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[0001] The present application is a continuation of PCT Serial No. PCT/US02/29356 filed on Sep. 17, 2002, now pending, which claims the priority of U.S. Provisional Patent Application Serial No. 60/325,806, filed on Sep. 28, 2001 (now abandoned) and 60/341,032, filed on Dec. 12, 2001 (now abandoned), and which is a continuation-in-part of U.S. Ser. No. 09/934,399, filed on Aug. 21, 2001 (now U.S. Pat. No. 6,695,815) which is a continuation of U.S. Ser. No. 09/511,100 filed on Feb. 23, 2000 (now U.S. Pat. No. 6,302,873). The disclosures of each of these prior related applications are hereby fully incorporated by reference herein.
FIELD OF THE INVENTION
[0002] This invention generally relates to cannulas and, more specifically, to cannulas used during minimally invasive surgery for allowing the introduction of instruments, such as laparoscopic tools, during surgical procedures.
BACKGROUND OF THE INVENTION
[0003] Minimally invasive surgery is a popular alternative to more traditional surgery. This is due to the fact that minimally invasive surgery generally results in less pain and shorter hospital stays for the patient. Also, the cost of performing a surgical procedure through minimally invasive techniques can be substantially less than more traditional surgical approaches.
[0004] Minimally invasive surgical techniques require access into the body of a patient through a small working channel of an apparatus known as a trocar-cannula complex. A relatively small access incision is made in the patient at the appropriate location on the patient to receive the trocar-cannula complex. When the trocar-cannula complex is combined with long, narrow instruments, the resulting assembly allows a surgeon to work inside the body through the small access incision or port site. This approach has resulted in the aforementioned clinical advantages and extensive health care cost savings.
[0005] Traditionally, the trocar-cannula complex has been configured with three parts. The first part is the top portion and is referred to in the medical industry as the hub. The hub defines the entrance to the trocar-cannula complex and also includes various seals and air insufflation components. The second part is the trocar, which is a long, narrow blade extendable through an inner cannula to allow smooth penetration into the body of the patient through the tissue layers. The third portion is an outer cannula which is a tubular member of the complex adapted to pass into the body cavity. The outer cannula provides an interface between the patient's tissue at the access incision or port site and the trocar assembly.
[0006] Minimally invasive surgery has grown in popularity in recent years and many new types of trocar-cannula products have been proposed and introduced to address different surgical needs and procedures. The various trocar-cannula complexes include reusable and disposable cannulas and trocars, as well as hybrid varieties that comprise combinations of reusable and disposable components of the trocar-cannula complexes. A complex which is a combination of reusable and disposable components is known as a resposable device. Such devices continue to improve surgical outcomes and economics.
[0007] Animal studies on cancer treatments involving the performance of minimally invasive surgery point to a growing body of evidence which supports the concept of delivering an irrigant to the port site after the surgical procedure. In these studies, the irrigants were delivered by a syringe and needle and included substances such as betadine, saline and lidocaine. These studies showed that irrigating the port site with such substances immediately after the surgical procedure beneficially resulted in a lower incidence of infection or less pain, depending on the irrigant. However, the technique also resulted in increased operative time and increased exposure of the surgical staff to needle sticks. In addition, the potential for contaminants to spread to the port site during the surgery has been well documented. Irrigation performed only at the end of the surgical procedure unfortunately cannot reduce patient exposure to contaminants during the procedure.
[0008] In view of the above-mentioned drawbacks in the field, there is a need for more effective delivery of fluids to an access point or port in the body of a patient before, during, and/or after the performance of minimally invasive surgery. Such delivery of fluid(s) could assist in patient treatment, such as through the delivery of cancer treatment medication or other medication, as well as reduction of port site contamination and infection, and reduction of post-operative pain. Other uses of the invention may be made in connection with delivering any desired fluid to a patient.
SUMMARY OF THE INVENTION
[0009] The present invention generally relates to a unique fluid delivery cannula which provides an interface between an access point or port in the body of a patient and a working channel which may receive tools or instruments used during minimally invasive surgery. In accordance with one general aspect of the invention, the cannula allows introduction of fluid(s) at the port site, or another site within the body of the patient, at any time after the cannula is introduced through the access point or port site of the body. The fluids may be introduced manually, such as through a manually operated syringe coupled in fluid communication with one or more fluid passages in or on the wall of the cannula. Alternatively, the fluids may be delivered automatically through a suitable medical pump or other device.
[0010] The fluids may include, for example, saline solution, lidocaine-containing fluids, betadine-containing fluids, or other substances, depending on the intended use and desired purpose. Presently, it is contemplated that such fluids will be especially beneficial to reduce post-operative pain, prevent infection and contamination at the port site and provide for many types of treatment to an affected area within the body of the patient. Another potential use is for delivering tissue adhesive to the patient.
[0011] In one embodiment, the fluid delivery cannula releasably attaches to the hub. In another embodiment, the fluid delivery cannula is integrally formed with at least a portion of the hub. As one example, the fluid delivery cannula may be integrally molded with a housing portion which is configured to receive valving components and/or other insufflation components, while also allowing the trocar to pass through into the fluid delivery cannula. The hub can include a fluid inlet comprising a coupling, such as a standard luer connection, for receiving a manually operated syringe device allowing for the injection of the desired fluids. The fluid delivery cannula preferably has, in addition to a main lumen for receiving the trocar, one or more fluid passages for irrigation purposes. In the preferred embodiments, the cannula has a layered construction with multiple fluid passages contained between two layers of the cannula. The outside surface of one layer of the cannula includes grooves or recesses in fluid communication with the fluid inlet and an outer layer of the cannula includes one or more apertures or perforations communicating with the grooves for dispensing the fluid. Also in the preferred embodiment, the outside portion of the cannula, which has the fluid dispensing apertures, provides a visual target zone for the accurate delivery of the fluid to the port site. For example, this may comprise using a different color, texture, or other visually identifiable indicia at that fluid dispensing location of the cannula such that the surgeon can accurately determine where the fluid is being directed.
[0012] The invention may be manufactured in many different manners while still functioning in accordance with the inventive principles. As mentioned above, the preferred form of the invention includes an inner cannula member having a grooved outer surface to define multiple fluid passages. An outer layer of biocompatible material (e.g., PTFE) is preferably heat shrunk onto the outer surface to enclose and seal the grooves to form passages. This biocompatible material includes, preferably, several apertures positioned around the circumference of the cannula and communicating with the grooves so that the fluid may be dispensed around the entire circumference of the cannula at a specific location along the length thereof. Alternatively, or in addition, fluid passages and one or more apertures may be provided only at one location about the circumference of the cannula for even more targeted delivery of the fluid.
[0013] As alternative embodiments, the outer layer may be comprised of a layer which is configured similar to a condom and rolled onto the cannula and which includes the necessary aperture(s) for fluid delivery to the patient. The outer layer may be a rigid layer which is coupled to the inner cannula member in a rigid fashion or, for example, in a movable fashion such as a rotatable fashion to allow opening, closing, or size adjustment of the fluid delivery passage(s). As one additional alternative, the outer layer may be formed at least partially of a porous material which provides the necessary apertures. Such porous materials may, for example, take the form of sintered metals, filter media, paper, mesh cloth or a porous plastic.
[0014] Another embodiment of the invention provides an expandable sleeve that may itself comprise a cannula through which a trocar or trocar assembly is inserted or which may take the place of the perforated outer layer of the grooved cannula discussed above. Other expandable sleeve embodiments may also be configured in accordance with this aspect of the invention as well. Such an expandable sleeve can, for example, allow trocars having different diameters to be inserted through the sleeve. Therefore, the same expandable fluid delivery sleeve may be used in connection with different sized trocars or trocar assemblies thereby reducing or eliminating the need for different sized fluid delivery cannulas or sleeves.
[0015] Various objects, advantages and features of the invention will become more readily apparent to those of ordinary skill upon review of the following detailed description of the preferred embodiment taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] [0016]FIG. 1 is a perspective view showing a trocar-fluid delivery cannula complex constructed in accordance with the invention and being used during a minimally invasive surgical procedure.
[0017] [0017]FIG. 2 is a cross sectional view taken generally along the longitudinal axis of the trocar-fluid delivery cannula complex of FIG. 1 for showing the irrigant flow path.
[0018] [0018]FIG. 3 is an enlarged cross sectional view similar to FIG. 2, but more clearly showing the flow path for the delivery of fluid through the cannula.
[0019] [0019]FIG. 4 is a cross sectional view taken along line 4 - 4 of FIG. 2.
[0020] [0020]FIG. 5 is a plan view of the fluid delivery cannula with the outer layer or sheath removed for clarity.
[0021] [0021]FIG. 6 is a plan view of another embodiment in which the fluid delivery cannula is integrally formed with a portion of a trocar hub.
[0022] [0022]FIG. 7 is a cross sectional view taken along line 7 - 7 of FIG. 6.
[0023] [0023]FIG. 8 is a longitudinal cross sectional view similar to FIG. 2, but illustrating an alternative embodiment of the invention incorporating an expandable fluid delivery sleeve.
[0024] [0024]FIG. 9 is a perspective view of another alternative embodiment of an expandable fluid delivery sleeve or cannula.
[0025] [0025]FIG. 10 is a cross sectional view taken along line 10 - 10 of FIG. 9.
[0026] [0026]FIG. 11 is an enlarged perspective view of the distal end of another expandable fluid delivery sleeve or cannula.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0027] [0027]FIG. 1 illustrates a trocar-fluid delivery cannula complex 10 constructed in accordance with one preferred embodiment of the invention. Complex 10 includes a trocar assembly 12 which may include a conventional hub assembly 14 . Representative trocar assemblies are shown and described in previous patents, such as my previous U.S. Pat. Nos. 6,063,060; 6,039,725; 5,865,817; and 5,865,809, the disclosures of which are hereby fully incorporated by reference herein. In accordance with the invention, a cannula 16 is positioned on the outside of trocar assembly 12 and includes a base portion 16 a . A syringe 18 couples to base portion 16 a of cannula 16 through a fluid coupling, such as a standard luer connector assembly 20 . A plunger 18 a of syringe 18 is used to manually inject a fluid into base portion 16 a of cannula 16 . An outer layer or sheath 24 , preferably formed of PTFE (Teflon®), is secured to the outer surface of an inner tube 26 of cannula 16 and includes apertures 22 . In the preferred embodiment, sheath 24 is a tube which is heat shrunk onto inner tube 26 but it may take other forms and may be secured in other ways. As will be described below, cannula 16 includes appropriate fluid passages communicating with an inlet passage in base portion 16 a to allow the fluid to be dispensed through apertures 22 as shown by arrows 28 . Hub assembly 14 further includes an insufflation valve 30 and a gas inlet 32 for receiving a pressurized gas, such as CO 2 .
[0028] As further shown in FIGS. 2 and 3, base portion 16 a of cannula 16 is threaded onto hub assembly 14 by threads 34 . Thus, cannula 16 may be easily coupled to and decoupled from hub assembly 14 . In the preferred embodiment, cannula 16 is disposable, however, it also may be manufactured as a reusable device intended to be sterilized between uses. Trocar assembly 12 more specifically comprises a trocar 50 received by a protective shield 52 . It will be appreciated that other instruments and tools may be inserted through the working channels formed by either irrigating cannula 16 or other tubular member(s) positioned within cannula 16 . This includes many other configurations of trocars or trocar assemblies as generally recognized in the art.
[0029] More specifically referring to FIGS. 3 - 5 , irrigation fluids are introduced through luer connector 20 a (FIG. 3) into fluid inlet 60 and groove or channel 62 formed in inner tube 26 of cannula 16 . Groove 62 communicates with an annular, circumferential groove 64 and groove 64 communicates with three separate longitudinal grooves 66 which are spaced in 120° increments about inner tube 26 . Grooves 66 respectively communicate with three partially annular grooves 68 which, in turn, each communicate with two longitudinal grooves 70 . Longitudinal grooves 70 communicate with apertures 22 in sheath 24 and apertures 22 thereby dispense the fluid at the port site 40 or, if cannula 16 is appropriately inserted and positioned, elsewhere within the patient.
[0030] As mentioned above, the outer sheath 24 of the cannula 16 is preferably formed of PTFE and, more preferably, the outer sheath 24 is transparent or at least translucent. In addition, the area of sheath 24 containing apertures 22 may be formed with a distinct color, texture or other visually identifiable indicia which allows the surgeon to accurately position the apertures 22 with respect to the tissue to be infused with irrigation fluid. The various grooves in the outside surface of the inner tube 26 may be substituted with one or more passages within the walls of the inner tube 26 and may be of any suitable configuration and shape so long as the function of delivering fluid through the wall of the cannula 16 is facilitated by the configuration. The outer wall or sheath is a heat shrinkable material, such as an elastomeric material, however, this may also be substituted by other components or even eliminated, for example, if the passages and apertures are in the wall of an integrally formed cannula or if another fluid delivery structure is carried on the outer cannula. The inner tube in the preferred embodiment is preferably formed from aluminum with the various grooves in its outer surface being machined, however, it may instead be formed of other materials, such as plastic materials, and formed by other techniques such as molding. The preferred embodiment is especially advantageous in that it is simple to manufacture and the outer sheath forms a seal at the upper and lower ends of the inner tube while, at the same time, defining walls of the internal passages formed by the various grooves.
[0031] [0031]FIGS. 6 and 7 illustrate a second illustrative embodiment of the invention comprising an fluid delivery cannula 100 which includes an irrigating portion 102 and a hub or housing portion 104 formed in one piece. For example, the entire structure shown in FIGS. 6 and 7 may be molded from a polymeric material, such as conventional medical grade polymers, using Mu-cell technology or other appropriate molding techniques. In FIGS. 6 and 7, the outer layer or sheath containing the one or more perforations has been removed for clarity. Housing portion 104 includes a port 106 for receiving valving and gas input components as are known in the art. A fluid input 108 is formed on cannula 100 and communicates with a passage 110 for the introduction of the necessary or desired fluids to irrigation portion 102 . A space 112 is provided for the necessary valving, sealing components, etc., typically used in trocar hubs. A lumen 114 extends along an axis 116 for receiving the trocar (not shown) and other working instruments. A system of fluid delivery passages is formed on the outside surface of irrigation portion 102 in the same illustrative pattern as discussed with respect to the first embodiment. This includes an annular groove 120 which communicates with passage 110 and delivers the fluid to three separate longitudinal passages 122 positioned at 120° increments around the outside surface of irrigation portion 102 relative to axis 116 . Grooves 122 communicate with respective partially annular grooves 124 . Again, while only two grooves 124 are shown in the drawings, a total of three grooves are formed in the outer surface of irrigation portion 102 positioned at 120° increments about axis 116 . Each partially annular groove 124 communicates with two separate longitudinal grooves 126 . Although only two grooves 126 are shown in FIG. 6, it will be appreciated that a total of six such grooves are formed in the outer surface of irrigation portion 102 in this particular embodiment. As in the first embodiment, grooves 126 communicate the fluid to perforations in the outer sheath (not shown) which then deliver the fluid to the patient. The outer sheath, as in the first embodiment, is preferably heat shrunk onto irrigation portion 102 so as to seal all of the grooves in the same manner as shown, for example, in FIGS. 2 and 3 of the first embodiment. As mentioned above, it will be appreciated that many other configurations of fluid delivery passages may be utilized in the cannula within the spirit and scope of this invention.
[0032] In FIG. 8, like reference numerals refer to like elements of structure between the two embodiments. In the alternative trocar-cannula complex 150 of FIG. 8, the outer sleeve or layer 24 (not shown) which was affixed to the grooved cannula 26 has been removed and replaced by an expandable sleeve 152 . Expandable sleeve 152 may be a layered construction including a mesh layer 154 and an outer elastomeric layer 156 . Layer 156 is uniformly perforated about its entire periphery, such as in a circumferential zone 158 as shown in FIG. 8, so that at least some of the perforations 160 line up with the longitudinal grooves 70 of the cannula 26 . Thus, fluid is delivered through input 20 a and into grooves 66 , 68 , 70 as described previously with respect to the first embodiment and this fluid is transferred through the expandable inner mesh layer 154 and expandable outer elastomeric layer 156 containing perforations 160 . It will be appreciated that many other forms than the layered mesh construction shown may be used in place of the expandable sleeve 152 shown in FIG. 8. FIG. 8 illustrates the use of the expandable sleeve 152 in connection with a 10 mm trocar assembly, however, in accordance with this aspect of the invention, the expandable fluid delivery sleeve 152 may alternatively be used with other trocars having larger or smaller diameters. A rigid handle portion 162 is provided at the proximal end of sleeve 152 to allow application and removal of sleeve 152 to and from trocar 12 . In order to seal the distal end of the expandable sleeve, a seal 164 may be provided distally of the mesh layer 154 as generally illustrated in FIG. 8. Alternatively, this seal 164 may be eliminated and the mesh layer 154 could then allow additional fluid to be delivered from the distal end of the sleeve 152 .
[0033] [0033]FIGS. 9 and 10 illustrate another embodiment of an expandable fluid delivery sleeve 200 which does not need the separate cannula 26 (FIG. 8) for fluid delivery as in the embodiment of FIG. 8. Instead, this sleeve 200 is formed in a manner allowing fluid delivery to take place via an input 202 and sleeve 200 alone. Sleeve 200 is formed of a layered construction including an outer perforated layer 204 , an intermediate mesh layer 206 , and an inner layer 208 . Each layer 204 , 206 , 208 is expandable such that sleeve 200 may be used effectively on trocars having different diameters. The intermediate mesh layer 206 allows fluid to travel through the interstices therein from an appropriate fluid passageway extending through input 202 and an upper handle portion 210 . Alternatively, other types of fluid passages may be utilized. A trocar (not shown) is inserted through the bore 212 at the proximal end such that it extends through the distal end 214 of the expandable sleeve 200 . Perforations 216 are preferably formed in a desired zone 218 of sleeve 200 generally as described with respect to the previous embodiments. This zone 218 may be formed of a different color or in any other manner which indicates the positioning of the perforations to the doctor during the surgical procedure. Although not shown in FIGS. 9 and 10, this sleeve 200 may also have a seal at the distal end 214 to prevent fluid from leaking out the distal end 214 .
[0034] As exemplified in FIG. 11, a distal end 230 of the expandable sleeves may be formed so as to allow fluid delivery to take place directly at the distal end. This aspect is shown in FIG. 11 schematically by indicating that the intermediate mesh layer 206 extends slightly beyond the other layers or is otherwise unsealed and, therefore, the fluid pathway through the mesh material 206 remains unblocked at the distal end 230 . This general aspect of fluid delivery from the distal end 230 may be used alone or in conjunction with fluid delivery from surface perforations as previously described.
[0035] Many different types of irrigation fluids may be introduced through the fluid delivery cannulas of this invention. These include, but are not limited to, saline solutions, lidocaine-containing fluids, betadine-containing fluids, cancer treatment fluids, or any other fluid necessary or desired for a particular medical procedure. In addition, fluids other than irrigation fluids or treatment fluids may be delivered through the cannulas of this invention. As one additional example, bioadhesives may be delivered to an incision site or any other necessary tissue repair site to provide for quicker and more effective administration of the adhesive to the desired site. Many different types of trocars and cannulas may be utilized within the scope of this invention. These trocars and cannulas may be inserted through a port site of a patient together in one operation or separately, for example, by using a needle introducer for an expandable cannula and subsequently introducing the trocar.
[0036] While the present invention has been illustrated by a description of a preferred embodiment and while this embodiment has been described in some detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The various features of the invention may be used alone or in numerous combinations depending on the needs and preferences of the user. This has been a description of the present invention, along with the preferred methods of practicing the present invention as currently known. However, the invention itself should only be defined by the appended claims, wherein I claim:
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A fluid delivery cannula which provides an interface between an access point or port in the body of a patient and a working channel which may receive tools or instruments used during minimally invasive surgery. The cannula allows introduction of fluid(s) at the port site, or another site within the body of the patient. The fluid delivery cannula can releasably attach to a hub associated with a trocar assembly or may be integrally formed with at least a portion of the hub. In one form, an inner cannula member includes a grooved outer surface to define multiple fluid passages and a perforated outer layer is placed over the inner cannula member. Another form provides an expandable sleeve that may itself comprise a cannula through which a trocar or trocar assembly is inserted or which may take the place of the perforated outer layer of the grooved cannula.
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CROSS-REFERENCE TO RELATED APPLICATION
U.S. patent applications Ser. No. 07/989,615, now U.S. Pat. No. 5,303,235 issued Apr. 12, 1994, Ser. No. 07/990,479 (now pending) and Ser. No. 07/990,385, now U.S. Pat. No. 5,335,229 issued Aug. 2, 1994 were filed concurrently herewith.
TECHNICAL FIELD
This invention relates to digital communications systems and, more particularly, to telecommunications management networks.
BACKGROUND OF THE INVENTION
In prior telecommunications management networks, it was necessary to manually input the identities of the communications system elements within the network. The identity information was required at each element in the network. Consequently, when a network element was either added or deleted, each of the elements would have to be manually updated with the identity of the element or elements being added or deleted from the network. Additionally, when adding a network element, all the identity information of the other elements in the network would have to be manually inputted into the new network element. Such manual inputting of the identity information into the network elements is not only time consuming, but prone to errors.
One telecommunications management network that uses a so-called "Directory Services Network Element" (DSNE) to automatically maintain identity information of network elements in a centralized data base is disclosed in co-pending United States patent application Ser. No. 07/990,479 (now pending). In the noted management network, the DSNE maintains all of the identity information of network elements within one or more sub-networks associated with it. One problem with such a management network is that proper operation of the centralized database depends on the ability of the network elements to communicate with the DSNE. If the DSNE fails, or the communications path between a network element and the DSNE fails, the network elements can no longer communicate with the DSNE and with each other. Another drawback of such a management network is that a network element must always query the DSNE before it can communicate with another network element in its sub-network. This, in turn, increases network communications traffic and introduces delays in inter-network element communications.
SUMMARY OF THE INVENTION
The problems related to a DSNE failure in a telecommunications management network are overcome, in accordance with the principles of the invention, by the DSNE automatically distributing the identity information of all network elements in a sub-network to all the network elements in that sub-network. Specifically, the DSNE automatically distributes all the identity information for all network elements within a sub-network to a newly registered network element and also supplies the identity information for the newly registered network element to all the other network elements within the sub-network. Since, each sub-network can be defined as a set of network elements that require significant communications with each other, distribution of the identity information for all the network elements in the sub-network to all the network elements in that sub-network significantly reduces the number of queries made to the DSNE. Furthermore, in the event of a DSNE failure, the network elements in a sub-network may still be capable of communicating with each other, thereby improving communications survivability.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawing:
FIG. 1 shows, in simplified block diagram form, details of a network element which may be employed either as a Directory Services Network Element (DSNE) or as a remote Network Element (NE);
FIG. 2 shows, in simplified block diagram form, a telecommunications network in which the invention may be incorporated;
FIG. 3 illustrates the operation of the invention using a particular protocol stack;
FIG. 3A is a flow chart illustrating the enhancement to the routing exchange protocol interface;
FIG. 4 is a flow chart illustrating the operation of an aspect of the invention in a Directory Services Network Element (DSNE);
FIG. 5 is a flow chart illustrating the operation of a distribution manager routine employed in the routine of FIG. 4;
FIG. 6 is a flow chart illustrating the operation of a distribution agent routine employed to interwork with the distribution manager routine of FIG. 5;
FIG. 7 is a flow chart illustrating the operation of the DSNE in updating all the network elements with new identity information;
FIG. 8 is a flow chart illustrating the operation of network elements other than the DSNE upon receiving the updated identity information;
FIG. 9 shows, in simplified block diagram form, a telecommunications network in which the invention may be practiced;
FIG. 10 is a table illustrating a directory information base (DIB) included in the DSNE of FIG. 9;
FIG. 11 is a table of identity information distributed by the DSNE to network elements A1, A2 and A3 of FIG. 9;
FIG. 12 is a table of identity information distributed by the DSNE to network elements B1, B2, B3 and B4 of FIG. 9;
FIG. 13 is a table of identity information distributed by the DSNE to network elements C1, C2, C3 and C4 of FIG. 9;
FIG. 14 shows, in simplified block diagram form, a telecommunications network in which a plurality of network elements are integrated into one network element illustrating an aspect of the invention;
FIG. 15 shows, in simplified block diagram form, details of DSNE 1402 employed in "DSNE" 1401 of FIG. 14;
FIG. 16 shows, in simplified block diagram form, details of network elements A1 * , B1 * and C1 * integrated into "DSNE" 1401 of FIG. 14;
FIG. 17 shows, in simplified block diagram form, one configuration, including integrated network elements into the single integrated network element of FIG. 14;
FIG. 18 is a table illustrating a directory information base included in the integrated "DSNE" 1401 of FIG. 14;
FIG. 19 is a table of identity information distributed by DSNE 1402 of FIG. 14 to integrated network element A1 * ;
FIG. 20 is a table of identity information distributed by the integrated "DSNE" 1401 of FIG. 14 to network elements A2 and A3;
FIG. 21 is a table of identity information distributed by DSNE 1402 of FIG. 14 to integrated network element B1 * ;
FIG. 22 is a table of identity information distributed by the integrated "DSNE" 1401 of FIG. 14 to network elements B2, B3, B4 and B5;
FIG. 23 is a table of identity information distributed by DSNE 1402 of FIG. 14 to integrated network element C1 * ; and
FIG. 24 is a table of identity information distributed by the integrated "DSNE" 1401 of FIG. 14 to network elements C2, C3 and C4.
DETAILED DESCRIPTION
FIG. 1 shows in simplified block diagram form, details of a Network Element 100 (DSNE/NE) which may be employed as either a Directory Services Network Element (DSNE) or a remote Network Element (NE) in a telecommunications management network. Hereinafter, Network Element 100 is referred to as DSNE/NE 100. Specifically, shown are microprocessor 101, read only memory (ROM) 102, random access memory (RAM) 103, non-volatile memory (FLASH) 104 and direct memory access unit (DMA) 105 which form a local processor complex within DSNE/NE 100. Such local processor complexes are known and operate in well-known fashion. Microprocessor 101 is interfaced via RS-232 driver/receiver 106 and LAPB controller 107 via circuit path 108 to an external network management system (not shown). Operation of units 106 and 107 are well-known in the art. Microprocessor 101 is also interfaced via IEEE 802.3 LAN controller 109 and circuit path 110 to a so-called intra-office local area network (LAN) (not shown). Additionally, microprocessor 101 is interfaced via LAPD controllers 111-1 through 111-N and corresponding optical interfaces 112-1 through 112-N, respectively, to fiber optic links 114-1 through 114-N. Again, LAPD controllers 111 and optical interfaces 112 are well-known in the art.
FIG. 2 shows, in simplified form, the logical operation of DSNE/NE 100 when configured as DSNE 201 and also as remote NE 204 to effect directory services registration, in accordance with the principles of the invention. Specifically, when configured as DSNE 201, DSNE/NE 100 of FIG. 1 is provisioned to provide Distribution Manager (DM) function 202 and includes a global Directory Information Base (DIB) 203. When configured as NE 204, DSNE/NE 100 of FIG. 1 is provisioned to provide Distribution Agent (DA) function 205 and includes local cache 206. As will be apparent to those skilled in the art, DSNE/NE 100 of FIG. 1 typically includes all the routines to effect both the functions of DSNE 201 and the functions of remote NE 204 and depending on how it is configured, the appropriate ones of DM 202, DIB 203, DA 205 and cache 206 will be activated.
FIG. 3 shows in simplified form, an Open System Interconnection (OSI) protocol stack 300 which includes at least network layer 3 including appropriate routing protocols and applications layer 7. It will be apparent that the OSI protocol stack typically would include other layers for supporting other functionality as desired by the implementor. Such an OSI protocol stack is known in the art and is defined in ISO/ICE 7498:1987. It is noted that in prior such OSI protocol stacks each layer operates independently of the other layers and was specifically designed to allow interaction between adjacent layers only and not between layers separated by other layers. In accordance with the principles of the invention, a so-called newly reachable remote NE element, for example, 204 of FIG. 2, is automatically registered in DSNE 201. This is realized, in accordance with the invention, by employing routing exchange protocols Intermediate System-Intermediate System (IS-IS) and End System-Intermediate System (ES-IS) in network layer 3 of the OSI protocol stack 300 to dynamically maintain identity information of newly reachable network element 204 in routing table 301 and by enhancing the routing exchange protocol interface to automatically supply an indication that either newly reachable network element 204 has been detected or an indication that an existing network element has ceased to be reachable directly to applications layer 7 of ISO protocol stack 300 and, specifically, therein to a directory distribution protocol. The enhancement to the routing exchange protocol and its interface, in accordance with the invention, is shown in FIG. 3A and described below. The directory distribution protocol in layer 7 interfaces with distribution manager 202 (FIG. 2) in such a manner as will be described below. It should be noted, however, that DSNE 201 and NE 204, as well as, any other NEs in a SONET Management Sub-system Branch (SMSB), will be operating the IS-IS and ES-IS routing protocols so that DSNE 201 will be able to automatically detect the presence of newly reachable network element or network elements which cease to be reachable, in accordance with the principles of the invention. Consequently, the indications of newly reachable network elements and indications that existing network elements cease to be reachable are maintained via distribution manager 202 automatically and the need for manually inputting such information, as was done in the past, is eliminated. Protocols IS-IS and ES-IS are well-known in the art and are defined in ISO/IEC 10589:1991 and ISO/IEC 9542:1988, respectively. Network layer 3 also includes a connectionless network protocol (CLNP) which provides a connectionless mode of network service, in well known fashion, as defined in ISO/IEC 8473:1988. Applications layer 7 also includes a subset of the directory services protocol as defined in CCITT Recommendation X.500: 1988. The associated control service element (ACSE), in applications layer 7, is employed to establish associations between applications routines residing in different network elements, in known fashion, and is defined in CCITT Recommendations X.217 and X.227. Specifically, by way of an example, there would be an association established via ACSE between the distribution manager (DM) in DSNE 201 and the distribution agent (DA) in remote NE 204.
FIG. 3A is a flow chart illustrating the enchancement made to the routing exchange protocol and its interface in the network layer, in accordance with the invention, to automatically supply an indication that either a newly reachable network element has been detected or an indication that an existing network element has ceased to be reachable directly to applications layer 7 of ISO protocol stack 300 (FIG. 3) and, specifically, therein to a directory distribution protocol. The routine of FIG. 3A would typically be stored in flash 104 of the DSNE/NE 100 (FIG. 1) and is employed when provisioned as a DSNE. Specifically, the routing exchange protocol is entered via step 311. Thereafter, step 312 causes the known normal protocol functions of the routing exchange protocol to be performed. It is noted as a result of such functions being performed, newly reachable network elements are added to routing tables in the routing exchange protocol and network elements that are no longer reachable are removed from the routing tables of the routing exchange protocol in known fashion. Then, step 313 tests to determine if any newly reachable network element(s) has been added to the routing table of the routing exchange protocol. If the test result in step 313 is no, step 314 is by-passed and control is passed to step 315. If the test result in step 313 is yes, control is passed to step 314 which generates an indication(s) that a newly reachable network element(s) has been detected which indication is automatically supplied directly to applications layer 7 and, therein, to the directory distribution protocol, in accordance with the invention. In this manner, the routing exchange protocol interface is enchanced, in accordance with the invention. Thereafter, step 315 tests to determine if any network element(s) which is no longer reachable has been removed from the routing tables of the routing exchange protocol. If the test result in step 315 is no, step 316 is by-passed and control is returned to step 312. If the test result in step 315 is yes, control is passed to step 316 which generates an indication(s) directly that an existing network element(s) has ceased to be reachable and automatically supplies the indication(s) to the applications layer 7 and, therein, to a directory distribution protocol, in accordance with the invention. Again, in this manner the routing exchange protocol interface is enhanced, in accordance with the invention. Thereafter, control is returned to step 312. Again, it is noted that the loop comprising steps 312 through 316 effects the enchancement to the routing exchange protocol and its interface, in accordance with the invention.
FIG. 4 is a flow chart illustrating the operation of DSNE 201 in automatically registering identity information of remote network elements, in accordance with the invention. The routine of FIG. 4 would typically be stored in flash 104 of the DSNE/NE 100 (FIG. 1) and is employed when provisioned as a DSNE. Specifically, step 401 indicates the DSNE 201 startup. Thereafter, step 402 causes a routing table to be obtained from network layer 3, specifically routing table 301 of FIG. 3. Then, step 403 tests to determine if there are any entries to register in routing table 301. It is noted that upon startup, the DSNE 201 is going to attempt to register all entries populated in routing table 301. The entries in routing table 301 are identity information, i.e., network addresses, of remote network elements forming one or more sub-networks with DSNE 201. If there are entries in routing table 301, step 404 will obtain the next entry. Upon obtaining an entry, step 405 will call a distribution manager (DM) routine which performs the automatic registration of the network address in accordance with the invention. The distribution manager routine is shown in FIG. 5 and described below. Upon performing the automatic registration in step 405, control is passed to step 406 which tests to determine whether a so-called SONET Management Sub-network Branch (SMSB) should be updated. If the test result in step 406 is yes, then, step 407 calls a DM update SMSB routine to effect the updating of the SMSB automatically, in accordance with the principles of the invention. Thereafter, control is returned to step 403, and steps 403 through 406 (or 407) are iterated until all network addresses of remote network elements in routing table 301 (FIG. 3) have been registered. Once there are no longer any entries in routing table 301 to be registered, control is passed to step 408 where the routine waits until a "newly reachable NE" indication is received from the enhanced routing exchange protocol interface, in accordance with the principles of the invention. Upon receiving the newly reachable NE indication, control is passed to step 409 and the DM registration routine of FIG. 5 is called. Again, the DM registration routine effects, in accordance with the principles of the invention, the automatic registration of the network address of the newly reachable remote NE. Thereafter, control is passed to step 410 which tests to determine whether an SMSB should be updated. If the test result in step 410 is no, control is returned to step 408. If the test result in step 410 is yes, then, step 411 calls a DM update SMSB routine to effect the updating of the SMSB automatically, in accordance with the principles of the invention. Thereafter, control is returned to step 408. Details of the DM update SMSB are shown in FIG. 7 and described below.
FIG. 5 is a flow chart illustrating the operation of the distribution manager (DM) registration routine employed in FIG. 4. Again, this routine is also stored in flash 104 (FIG. 1). Specifically, the DM registration routine is entered via step 501. Thereafter, step 502 starts a timer. The interval of the timer is such as to allow for the automatic registration of a remote network element, e.g., NE 204 (FIG. 2) and is left to the implementor. Step 503 causes DSNE 201 (FIG. 2) to send a registration initialization request to the remote NE 204 and, therein, to a so-called distribution agent (DA) routine which is shown in FIG. 6 and described below. Step 504 causes DSNE 201 to wait for either a response from the DA in the remote NE 204 or the time out of the timer in step 502. Step 505 tests to determine if the timer has timed out. If the result is yes, the timer has timed out and control is returned to the routine in FIG. 4. If the test result in step 505 is no, step 507 causes DSNE 201 to receive a valid response, i.e., receive registration initialization response from the DA in the remote NE 204. Step 508 tests whether the DA in the remote NE 204 successfully provided a valid response. If the test result is no, control is returned via step 506 to the routine of FIG. 4. If the test result in step 508 is yes, a valid response has been received and step 509 causes the DSNE 201 to receive a registration add request from the DA in the remote NE 204. Thereafter, step 5 10 tests to determine whether the name and address, i.e., the identity information of the remote NE 204 is valid. If the test result is no, step 511 sends a registration add response error indication to the DA in the remote NE 204 and control is returned via step 506 to the routine shown in FIG. 4. If the test result in step 510 is yes, the identity information of the remote NE 204 is valid and step 512 causes that identity information and an update flag to be added to global D1B 203. Thereafter, step 513 automatically causes a registration add response success indication along with identity information of DSNE 201, in accordance with the principles of the invention, to the DA in the remote NE 204. Then, step 514 tests to determine whether the update flag supplied in step 512 indicates that the SMSB information should be updated. That is, whether or not the newly registered remote NE 204 should receive, in accordance with the principles of the invention, identity information of any other network elements in the SMSB including NE 204. If the test result in step 514 is no, control is returned via step 506 to the routine of FIG. 4. If the test result in step 514 is yes, step 515 causes an update SMSB indication to be supplied to the routine of FIG. 4 which, in turn, as indicated above, causes the identity information of the remote NE 204 to be automatically distributed to any other elements in the SMSB including NE 204, in accordance with the invention.
FIG. 6 is a flow chart of the distribution agent (DA) routine employed in the remote network elements to automatically provide identity information to the DSNE. The routine is also typically stored in flash 104 of each of the network elements (FIG. 1). Specifically, the DA routine is entered via step 601. Thereafter, step 602 causes the remote NE 204 (FIG. 2) to receive a registration initialization request from the DM routine of FIG. 5 employed in DSNE 201 (FIG. 2). Then, step 603 tests to determine whether the registration initialization request is valid. If the test result is no, step 604 causes a registration initialization response error to be sent to the DM routine of FIG. 5 in DSNE 201. Thereafter, the routine is exited via step 605. If the test result in step 603 is yes, a valid registration initialization request has been received and step 606 causes a registration initialization response success indication to be sent to the DM routine of FIG. 5 in DSNE 201. Step 607 causes a timer to be started. The interval of the timer is such as to allow the identity information of the remote NE 204 to be sent to the DM routine in DSNE 201 and obtain a response indicating reception from the DM routine of FIG. 5 in DSNE 201. Then, step 608 causes a registration add request with the NE 204 identity information to be automatically sent to the DM routine in DSNE 201, in accordance with the principles of the invention. Step 609 causes the DA to wait for a response from the DM or time-out of the timer. Step 610 tests to determine if the timer interval has elapsed. If the test result in 610 is yes, no response has been obtained from the DM and the routine is exited via step 605. If the test result in step 610 is no, a response has been obtained from the DM and step 611 causes reception of the registration add response from the DM routine in DSNE 201. Then, step 612 tests to determine whether the received registration add response is valid. If the test result is no, the routine is exited via step 605. If the test result in step 612 is yes, the registration add response is valid and step 613 causes the identity information of DSNE 201 to be stored in local cache 206 (FIG. 2) of NE 204, in accordance with the principles of the invention.
FIG. 7 is a flow chart showing the steps of the DM update SMSB routine of FIG. 4. Specifically, the DM update SMSB routine is entered via step 701. The routine is typically stored in flash 104 of the DSNE/NE 100 (FIG. 1) and is employed when provisioned as a DSNE. Then, step 702 causes the SMSB identity information to be retrieved from global directory information base (DIB) 203 in DSNE 201 (FIG. 2). Step 703 tests to determine if any of the SMSB network elements require to be updated. If the test result is no, control is returned via step 704 to the routine of FIG. 4. If the test result in step 703 is yes, a timer is started. The interval of the timer is such as to allow the identity information for the SMSB to be distributed to a network element in the SMSB. Then, step 706 causes an update request with the SMSB information to be sent to the DA in a network element, e.g. NE 204. Step 707 causes DSNE 201 to wait for a response or time out of the timer in step 705. Step 708 tests to determine if the timer has elapsed. If the test result is yes, control is passed to step 712. If the test result in step 708 is no, step 709 causes DSNE 201 to receive an update response from the DA of the remote NE 204. Then, step 710 tests to determine whether an update flag supplied from the DA in remote NE 204 is changed. If the test result is no, control is passed to step 712. This indicates that the particular remote NE will continue to receive further updates concerning SMSB identity information. If the test result in step 710 is yes, step 711 causes the update flag for this particular remote NE to be changed in global DIB 203 (FIG. 2). This indicates that the particular remote NE will no longer receive updates concerning SMSB identity information. Thereafter, step 712 tests to determine if any more of the SMSB network elements require to be updated. If the test result in step 712 is no, control is returned via step 704 to the routine of FIG. 4. If the test result in step 712 is yes, then, control is returned to step 705 and steps 705 through 712 are iterated until all necessary network element updates are performed. It is noted that while the invention is described herein in terms of the updates performed following the addition of new network elements to the network, the principles of the invention are equally applicable to applications that require updating of SMSB information; such an application would include, but not be limited to, the updates required following a modification of identity information (e.g., a change in TID) of a network element in a sub-network.
FIG. 8 is a flow chart illustrating the operation of the update SMSB distribution agent routine employed in the remote network elements, e.g., NE 204 (FIG. 2), to automatically update the local cache in the network element. The routine is typically stored in flash 104 of each of the network elements. Specifically, the DA update SMSB routine is entered in step 801. Thereafter, step 802 causes the network element to receive an update request from the DM in DSNE 201. Then, step 803 causes the local cache in NE 204 to be updated with the new SMSB identity information. Step 804 causes an update response with an update flag to be sent to the DM in DSNE 201. Thereafter, the DA update SMSB routine is exited via step 805.
FIG. 9 shows, in simplified block diagram form, a sample network 900 incorporating the inventions. Specifically, shown is network management system 901 which may be, for example, a known operations and support system employed to manage a telecommunications network. Network management system 901 is interfaced to DSNE 902 which may be, for example, a Digital Access and Cross Connect System (DACS), a digital multiplexer or the like. One such Digital Access and Cross Connect System which may be employed in practicing the invention is the DACS IV-2000, commercially available from AT&T, and one such digital multiplexer which may be employed in practicing the invention is the DDM-2000, also commercially available from AT&T. DSNE 902 and network management system 901 communicate via link 903 using, for example, the known X.25 packet protocol. Referring to FIG. 1, the interface in DSNE 902 to communications link 903 is RS-232 Driver/Receiver 106 and LAPB controller 107. DSNE 902 communicates via local area network (LAN) 904 with a number of sub-networks. In this example, DSNE 902 interfaces via LAN 904 with sub-network A, including network elements A1, A2 and A3, sub-network B, including network elements B1, B2, B3 and B4 and sub-network C, including network elements C1, C2, C3 and C4. Again, referring to FIG. 1 the interface in DSNE 902 to LAN 904 is, in this example, IEEE 802.3 LAN controller 109, which is well known in the art. Similarly, in sub-networks A, B, and C, network elements A1, B1 and C1 each interface to LAN 904 via IEEE 802.3 LAN controller 109 (FIG. 1). In sub-network A, network elements A1, A2 and A3 communicate with each other via optical links. Specifically, network element A1 communications with network element A2 via optical link 905 and network element A2 communicates with network element A3 via optical link 906. As also shown in FIG. 1, in this example, LAPD controller 111 and optical interface 112 are employed to interface with a corresponding optical link in sub-network A. Similarly, in sub-network B, network elements B1, B2, B3 and B4 interface with each other via optical links. Specifically, network element B1 communicates with network element B2 via optical link 907, network elements B2 and B3 communicate via optical link 908 and network elements B2 and B4 communicate via optical link 909. In this example, a LAPD controller 111 and an optical interface 112 are employed to interface with each of the corresponding optical links in sub-network B. Finally, in sub-network C, network elements C1, C2, C3 and C4 interface with each other via optical links. Specifically, network elements C1 and C2 communicate via optical link 910, network elements C2 and C3 communicate via optical link 911, network elements C3 and C4 communicate via optical link 912 and network elements C4 and C1 communicate via optical link 913. In this example, a LAPD controller 111 and an optical interface 112 are employed to interface with a corresponding optical link. It is noted that each of the network elements, including DSNE 902, has its own unique network address and unique name specific to the telecommunications management network. It should also be noted that communications among network elements (DSNE and/or NEs) is via a data communications channel (DCC).
FIG. 10 is a table of directory information base (DIB) included in DSNE 902 of FIG. 9. Shown are the network names, i.e., target identifiers (TIDs), network addresses, i.e., network service access points (NSAPs) of the network elements and which SMSB the particular network element is included in. NSAPs are defined in ISO/IEC 8348:1987/addendum 2:1988. However, for simplicity and clarity of exposition NSAPs having fewer numbers are described here. Thus, for example, DSNE 902 having NSAP "xy 2744" is included in all the SMSB's. Network elements A1 through A3 having NSAPs "xy 9247", "xy 7741" and "xy 1012", respectively, are included in SMSB "A", network elements B1 through B4 having NSAPs "xy 2571 ", "xy 3314", "xy 0241" and "xy 4447", respectively, are included in SMSB "B" and network elements C1 through C4 having NSAPs "xy 5893", "xy 2727", "xy 4155" and "xy 6002", respectively, are included in SMSB "C".
FIG. 11 shows a table of identity information distributed by DSNE 902 of FIG. 9, in accordance with the principles of the invention, to network elements A1, A2 and A3 of sub-network A. It is noted that the network names and network addresses of the other network elements in the sub-network A and the DSNE are supplied to each network element. Again, the DSNE and NEs A1, A2 and A3 form SMSB "A".
FIG. 12 is a table of identity information distributed by the DSNE 902 of FIG. 9, in accordance with the principles of the invention, to network elements B1, B2, B3 and B4 of sub-network B. It is noted that the network names and network addresses of the other network elements in the sub-network B and the DSNE are supplied to each of the network elements. Again, the DSNE and NEs B1, B2, B3 and B4 form SMSB "B".
FIG. 13 is a table of identity information distributed by the DSNE 902 of FIG. 9, in accordance with the principles of the invention, to network elements C1, C2, C3 and C4 of sub-network C. It is again noted that the network names and network addresses of the other network elements in the sub-network C and the DSNE are supplied to each of the network elements. Again, the DSNE and NEs C1, C2, C3 and C4 form SMSB "C"
FIG. 14 shows, in simplified block diagram form, a telecommunications management system 1400 in which network elements, or portions thereof, are integrated with DSNE 1402 to form a single new "DSNE" 1401. The telecommunications network of FIG. 14, from an apparatus point of view, is similar to that of FIG. 9, except that network elements A1 * , B1 * and C1 * , or portions thereof as will be explained below, are essentially integrated with DSNE 1402 to form a so-called new "DSNE" 1401, which appears to the sub-networks as a single network element from an OAM&P perspective. Again, this is realized, in accordance with the invention, by provisioning the network element being integrated, or a portion thereof, so that it can only provide its identity information to DSNE 1402 and can only receive identity information of DSNE 1402. DSNE 1402 will not provide the identity information of any of the integrated network elements to any of the other network elements in the sub-network which is interfaced to it. DSNE 1402 performs both end systems functions, as well as, intermediate systems functions. That is to say, DSNE 1402 is capable of terminating applications messages, as well as, routing and relaying messages to SMSBs A, B and C, in this example. Those network elements of network 1400 which are essentially identical to those shown in network 900 of FIG. 9 are similarly numbered and will not be described in detail again.
Thus, in telecommunications network 1400, new "DSNE" 1401 appears, in accordance with the invention, to be a single integrated DSNE to each of sub-networks A, B and C. In this example, however, sub-network A now includes only network elements A2 and A3, sub-network B now includes network elements B2 through B5 and sub-network C now includes only network elements C2 through C4. Network elements A1 * (1403), B1 * (1404) and C1 * (1405) are integrated into new "DSNE" 1401 and appear as "routers" or so-called "intermediate systems" (ISs) to the other network elements in SMSBs A, B and C, respectively. In this manner, new "DSNE" 1401 can provide optical interfaces to each of sub-networks A, B and C of FIG. 14 without the need of expending significant development time and cost.
Referring to FIG. 15, shown in simplified form, are details of DSNE 1402 of FIG. 4. Note that, the only difference between DSNE 1402 of FIG. 15 and DSNE/NE 100 of FIG. 1 are that unnecessary elements have been eliminated. In DSNE 1402 flash memory 104 LAPD controller 111 and optical interfaces 112 have been eliminated. Otherwise, the remaining elements in DSNE 1402 are identical to those in DSNE/NE 100 of FIG. 1 and have been similarly numbered and will not be described again.
Referring to FIG. 16, shown in simplified form, are details of the network elements A1 * , B1 * and C1 * of FIG. 14. Note that the only differences between the network element of FIG. 16 and the network element of FIG. 1 are that the RS-232 driver/receiver 106 and LAPB controller 107 of FIG. 1 have been eliminated. Otherwise, the remaining elements in the network element of FIG. 16 have been similarly numbered to those in FIG. 1 and will not be described again.
FIG. 17 shows, in simplified form, an implementation of "DSNE" 1401 employing commercially available equipment units. Specifically, shown is a DACS IV-2000 (1702), which is commercially available from AT&T, which would interface with the external network management system (not shown) and interface via a LAN 904 to DDM-2000 digital multiplexer units, or portions thereof (see FIG. 16), namely, 1703, 1704 and 1705 to provide optical interfaces to a plurality of SMSBs A, B and C, respectively. To this end, the SONET data communications channel from each of the DDM-2000's integrated into the DSNE would be utilized to communicate with remote network elements in each of the sub-networks. Specifically, the SONET data communications channel bytes D1-D3 and/or D4-D12 of the SONET overhead channel.
FIG. 18 is a table of directory information base (DIB) included in DSNE 1402 of FIG. 14. Shown are the network names (TIDs), network addresses (NSAPs) of the network elements and which SMSB the particular network element is included in. Thus, for example, DSNE 1402 is included in all the SMSBs. Network element A1 * is included in sub-network A * . Network elements A2 and A3 are included in sub-network A. Network element B1 * is included in sub-network B * . Network elements B2 through B5 are included in sub-network B. Network element C1 is included in sub-network C * . Network elements C2 through C4 are included in sub-network C. It is noted that the network elements having an * indicates that they are integrated into "DSNE" 1401. Thus, the new single "DSNE" 1402 includes DSNE 1402 and NEs A1 * B1 * and C1 * .
FIG. 19 shows a table of identity information distributed by DSNE 1402, in accordance with the principles of the invention, to network element A1 * . It is noted that the identity and name of network element A1 * is only shared with DSNE 1402. Network element A1 * appears transparent to network elements A2 and A3 of sub-network A from an Operations, Administration, Maintenance and Provisioning (OAM&P) perspective.
FIG. 20 shows a table of identity information distributed by DSNE 1402 via network element A1 * and, hence, "DSNE" 1401 of FIG. 14 to network elements A2 and A3 of sub-network A. It is noted that the network names and network addresses of the other network elements in the sub-network and DSNE 1402 are supplied to each network element in the sub-network A. "DSNE" 1401 and NEs A2 and A3 form SMSB "A".
FIG. 21 shows a table of identity information distributed by DSNE 1402, in accordance with the principles of the invention, to network element B1 * . It is noted that the identity and name of network element B1 * is only shared with DSNE 1402. Network element B1 * appears transparent to network elements B2 through B5 of sub-network B from an Operations, Administration, Maintenance and Provisioning (OAM&P) perspective.
FIG. 22 is a table of identity information distributed by DSNE 1402 via network element B1 * and, hence, "DSNE" 1401 of FIG. 14, in accordance with the principles of the invention, to network elements B2, B3, B4 and B5 of sub-network B. Again, it is noted that the network names and network addresses of the other network elements in the sub-network B and DSNE 1402 are supplied to each of the network elements. "DSNE" 1401 and NEs B2, B3, B4 and B5 form SMSB "B".
FIG. 23 shows a table of identity information distributed by DSNE 1402, in accordance with the principles of the invention, to network element C1 * . It is noted that the identity and name of network element C1 * is only shared with DSNE 1402. Network element C1 * appears transparent to network elements C2 through C4 of sub-network C from an Operations, Administration, Maintenance and Provisioning (OAM&P) perspective.
FIG. 24 is a table of identity information distributed by DSNE 1402 via network element C1 * and, hence, "DSNE" 1401 of FIG. 14, in accordance with the principles of the invention, to network elements C2, C3 and C4 of sub-network C. Again, it is noted that the network names and network addresses of the other network elements in the sub-network C and DSNE 1402 are supplied to each of the network elements. "DSNE" 1401 and NEs C2, C3 and C4 form SMSB "C".
The above-described arrangements are, of course, merely illustrative of the application of the principles of the inventions. Other arrangement may be devised by those skilled in the art without departing from the spirit or scope of the inventions. Although the arrangements are described herein in the context of telecommunications systems, it will be apparent that they are equally applicable to other types of data communications systems, for example, but not limited to, data communications between various types of computers as network elements. Additionally, it should be noted that the network elements (DSNE(s) and/or NE(s)) may interface with any desired number of other network elements.
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In a telecommunications management network including a network element provisioned as a so-called Directory Services Network Element (DSNE) and at least one sub-network intended to include one or more network elements, the DSNE automatically distributes the identity information of all network elements in a sub-network to all the network elements in that sub-network. Specifically, the DSNE automatically distributes all the identity information for all network elements within a sub-network to a newly registered network element and also supplies the identity information for the newly registered network element to all the other network elements within the sub-network. Since, each sub-network can be defined as a set of network elements that require significant communications with each other, distribution of the identity information for all the network elements in the sub-network to all the network elements in that sub-network significantly reduces the number of queries made to the DSNE. Furthermore, in the event of a DSNE failure, the network elements in a sub-network may still be capable of communicating with each other, thereby improving communications survivability.
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BACKGROUND
[0001] This relates generally to devices that are useful in reducing the likelihood of falls by the elderly or the infirm.
[0002] Falling is a major cause of injury and mortality in elderly citizens. The risk of a fall in elderly people has been estimated at 30 percent per year for people older than 65 years of age. Of those who fall, 20 percent will need medical intervention, while 19 percent will result in a fracture. After the age of 65 years, one person in three will fall at least once a year, all of which makes falls the greatest cause of death in elderly people. Even non-injurious falls have significant negative consequences for the individual because of the fear of falling, functional deterioration, anxiety, depression, and loss of confidence. There is evidence that, if not detected and treated early enough, a person who is prone to fall may pass a threshold after which intervention for risk factors are inadequate to reduce further falls and to prevent a cascade of inevitable decline, loss of independence, and eventual institutionalization.
[0003] The elderly and infirm may use handrails for support. This may be due to lack of mobility, lack of balance, or reduced eyesight. Elderly or infirm people may use stair banisters and supporting handrails to support themselves as they move from one location within their home to another. Handrails are particularly common on stairways and in bathrooms and are frequently installed in other rooms as well.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a front elevational view of one embodiment of the present invention;
[0005] FIG. 2 is a schematic depiction of the embodiment of FIG. 1 ; and
[0006] FIG. 3 is a flow chart for one embodiment of the present invention.
DETAILED DESCRIPTION
[0007] Referring to FIG. 1 , a handrail 12 is shown in position over a stairway indicated as S. However, the handrail may be positioned in a number of other locations as well, and may be along both inclined and horizontal walkways. For example, handrails may be provided in bathrooms proximate to toilets, sinks, bathtubs, and showers. They may also be provided along walkways in homes, hospitals, and other buildings.
[0008] The handrail 12 includes a force sensor 14 on its upper surface that detects the magnitude of an applied force, and the nature of applied force. By “nature of the applied force”, it is intended to refer to the ability to determine information about a surface area that applies the force to the handrail. In some embodiments, this information may indicate whether the user is simply touching the handrail with fingertips, palms, or actually grasping the handrail.
[0009] In one embodiment, the sensor 14 may be a Kinotex® tactile force sensor, available from Tactex Controls, Inc., Victoria, B.C., Canada. This force sensor provides the information about both the magnitude of force, and the area through which the force is applied. The tactile force sensor may include a sensor that measures minute displacements due to forces applied on its surface. It may be constructed of plastic fiber embedded in foam. Thus, it may flexible or rigid and can operate with soft surfaces or from beneath durable wear layers. A single sensing element, called a taxel, is comprised of a send-and-receive fiber. Red light at 650 nanometers shines through the transmit fiber to illuminate the form. An external force compressing the foam increases the intensity of backscattered light. The intensity of light is monitored by a receive fiber. The receive fiber is coupled to a photodiode that measures the light level returned from the received fiber.
[0010] The tactile force-sensing material 14 may be positioned over the entire length of the handrail 12 in some embodiments. This enables the monitoring of force while the user moves along the handrail 12 . The material 14 can be used to determine how the handrail 12 is being used, when the force is applied, how much force is applied, how much dependence on the handrail is indicated, and how the handrail is being grasped, for example by wrapping the fingers around the handrail, by simply putting the palm on the handrail, or by touching the handrail with fingertips. Each of these items may raise risk factors, and may also be used over time to indicate changes in patterns of activity, which may be indicative of the need for assistance.
[0011] For example, increased dependence on the supporting handrail may indicate that the person is experiencing balance or gait difficulties indicating an increased possibility of a fall. A long-term trend of increasing dependency on the handrail may suggest that the user should be alerted to his or her increased imbalance and instability. In addition, the longterm monitoring trend of applied pressure by the user's hand on the rail during movement along the handrail can be used to indicate changing ambulatory confidence or the need for physical support. When a trend towards imbalance or instability is detected, a feedback mechanism may alert the user to the possibility of a fall or allow caretakers to monitor the person.
[0012] For example, a feedback mechanism in the form of an audio message may alert the user to be more careful based on the way that the user is using the handrail.
[0013] Another problem is that falls on stairs may be due in part to poor visibility. Light-dependent diodes 10 may be provided along the length of the handrail 12 , for example near the stairs S, to monitor lighting conditions both at the top and bottom of the stairs. If the lighting condition is below a predefined level of illumination, a voice alert may prompt the user to turn on a light before moving along a handrail. This illumination condition may be examined when the person attempts to use the handrail, upon initial contact with the handrail sensor 14 .
[0014] Data on the pressure applied to the handrail 12 , dependency on the handrail 12 , and usage patterns may be communicated by the handrail sensors 14 to a server (not shown) that can then be accessed by caregivers for review and trend analysis. For example, wireless networking communication may be used to communicate the information from a location where the user is present, such as in the home, to a location where caregivers are present, such as a hospital or doctor's office or other monitoring facility.
[0015] In one embodiment, the feedback to the user may be in the form of a vibrating array 15 embedded within the handrail 12 . Upon feeling the vibration, the user is alerted to the imbalance situation, which may suggest the possibility of a fall and may be thereby advised to proceed more carefully or to summon assistance. The use of a vibratory feedback eliminates the possibility that those with impaired hearing may miss other warnings, especially audible warnings.
[0016] Thus, referring to FIG. 2 , in accordance with one embodiment of the present invention, a processor-based system may include a processor 20 . The system may be located at the user's premises or may be located remotely. The processor 20 may be coupled through a chipset 24 to a bus 18 . The bus 18 may be coupled to an interface 16 to the sensor array 14 . The processor 20 may also be coupled to a memory 22 storing a program 32 to be described hereinafter.
[0017] The chipset may also be coupled to a vibratory array 15 embedded within the sensor array 14 . The vibratory array 15 may use piezoelectric actuators in one embodiment.
[0018] The light monitor array 10 may monitor the lighting conditions along the handrail. In some cases the array 10 may control the lights to turn the lights on automatically or to turn the lights on to a brighter level as needed.
[0019] A network interface 36 may provide wired or wireless communication to a remote server where a caregiver may be located in some embodiments.
[0020] An audio interface 28 may interact with a speaker 30 which may provide audible warnings to the user as described above. In some embodiments, a microphone 29 may be provided to enable the user to provide verbal information. This verbal information may involve an immediate feedback from the user, such as summoning help, or may be simply recorded and passed with other information for further analysis. For example, the user may simply indicate that the user is having difficulty with the stairs, and this together with the force information may be analyzed at the remote location at a subsequent time.
[0021] Referring to FIG. 3 , in some embodiments, a monitor program 32 may be stored in the memory 22 . In such case, the memory 22 may be a computer-accessible medium in the form of a semiconductor memory, a magnetic memory, or an optical memory, to give some examples.
[0022] In one embodiment, a check of diamond 34 determines whether the sensors 14 in the handrail 12 are active. They activate immediately upon touch by the user in one embodiment. For example, only the uppermost and lowermost sensors may be continually active and the others may be powered down. As soon as one of the sensors at the top or bottom of the stairway S is contacted, all the sensors may be immediately turned on. Whenever one of these upper or lower sensors is touched, the sensor active indication is returned at diamond 34 , all the sensors are turned on, and the recording of a force pattern begins as indicated in block 36 .
[0023] The recording of the force pattern may involve recording not only the magnitude of the force but also the area of contact. The area of contact may be transformed into a determination of whether the user is providing only fingertip contact, palm contact, or grasping contact of the handrail.
[0024] After the user has traversed at least an initial portion of the handrail 12 , the pattern of applied force may be compared to thresholds, as indicated in block 38 . Thus, as part of traversing the entire stairway, an initial assessment may be made. That assessment may involve an assessment of the real-time information as well as a comparison to historical patterns of usage to determine whether any indication that a dangerous situation has arisen may be derived. If the force pattern is out of the threshold or inconsistent with the pattern history, as determined in diamond 40 , an alert may be issued at 42 . This alert may be an audible alert, for example through the speaker 30 , a vibratory alert through the vibratory array 15 , or the summoning of assistance from a caregiver.
[0025] Next, a check at block 44 determines whether the light intensity along the handrail 12 is adequate. If not, as determined in diamond 46 , an alert may be issued at block 48 . The alert may again be an audible, vibratory, or remote notification alert. It may also actually involve activating lights to provide additional illumination.
[0026] If the lighting is okay, a check at diamond 50 compares the force history to a threshold. For instance, as more data is provided as the user traverses the handrail, better and better comparisons to force history may be achieved. If the force history is out of the threshold range, as determined in diamond 52 , another alert of the type already described may be issued.
[0027] Other situations that may be monitored may be the lack of continued contact with the handrail after beginning contact. If it is determined that the user has neither continued up the stairway nor turned around and returned, based on contact with the handrail, an alert may be issued because it is possible that the user has actually fallen.
[0028] While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
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A monitor, which may be closely associated with a handrail, may determine the amount of force applied to the handrail. The monitor may also determine the pattern in which force is applied to the handrail in order to assess how the user is contacting the handrail. The user's application of force to the handrail can be monitored along the course of movement along the handrail and may be compared to historical usage patterns.
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BACKGROUND
The present invention relates to cooking ovens. More particularly, the field of the present invention is that of grease splatter capture shields for use in impingement and other ovens.
Impingement ovens provide accelerated cooking times in many applications. In the operation of an impingement oven, columnated jets of hot air or steam are directed at food items and transfer heat at a much greater rate than in convection ovens. Impingement oven systems are disclosed in U.S. Pat. Nos. 4,626,661 and 4,438,572, which are explicitly incorporated by reference herein.
One problem with oven cooking involves grease and fat in food items being cooked. For example, chickens have fat which renders out during cooking. As the jets of hot air flow over the chicken in an impingement oven, fat vaporizes and is carried away from the baking pan. Usually something blister pops, or a similar occurs, and the fat spatters into the cooking chamber to be carried by various air flows. The air with vaporized fat then circulates around the oven and deposits the fat, thereby severely soiling the interior of the oven. This problem is exacerbated by a grill rack which compresses the chicken to improve its cooking, because the internal vapor pressure and moisture pressure developed by the grill rack causes additional splatter.
Some attempts to solve this problem involved enveloping the pan, grill, and food product to contain the grease. These attempts fail because they effectively stop the impingement air flow and increase cooking time
Also, grease extractors are known for ventilator hoods in laboratories, but such extractors rely on high velocities of air movement. For impingement ovens, grease moves at a relatively low velocity as it comes off the food product and forms deposits on the oven interior before being drawn through the air recirculation system.
Another problem with impingement ovens involves the basting of items such as chickens. A significant amount of the chicken's natural moisture is vaporized and carried away in the air flow. Sometimes, the chicken will be aesthetically unpleasing because it has dried out during its cooking in the impingement oven. At other times, the chicken is not dried but may lack the full flavor of a chicken baked and basted in a conventional oven.
One object of the present invention is to provide a splatter capture shield which prevents the escape of fat and grease into the oven interior while still allowing the jets of air to cook the food item.
Another object of the present invention is to provide a splatter capture shield which self-bastes the food item.
SUMMARY OF THE INVENTION
The present invention is a capture shield for impingement ovens which prevents vaporized grease or fat from exiting the baking pan, but allows the hot jets of air to cook the food item. To accomplish this, a plurality of elongate shield elements extend over the pan and block any direct flow of air. The air flow diverts around the shield elements, so suspended fat and grease impact on the sides of the elements, deposit on the sides, and accumulate. Eventually, the deposited fat and grease drip back down onto the food item. Thus, the capture shield of the present invention provides self-basting impingement cooking while greatly preventing grease deposits on the oven itself.
The present invention, in one form, is a splatter capture shield for a baking pan and grill rack in an impingement oven. The capture shield comprises a pair of side walls, a pair of end aprons, and a plurality of elongate shield elements. The end aprons are connected between the side walls, with the end aprons adapted to fit over the grill rack. The shield elements have two ends attached to the side walls and are arranged between end aprons. The shield elements vertically overlap and obstruct a direct line-of-sight from over the shield to the baking pan, and are spaced apart to allow air to pass through substantially all of the capture shield.
BRIEF DESCRIPTION OF THE DRAWINGS
The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a side view of a baking pan and capture shield assembly of the present invention wherein the shield is shown in section.
FIG. 2 is an exploded view of FIG. 1.
FIG. 3 is a top view of the capture shield of the present invention.
FIG. 4 is a diagrammatic end view of the capture shield.
FIG. 5 is a diagrammatic end view of a pan and alternative embodiment of the present invention.
FIG. 6 is a diagrammatic end view of a V-configuration embodiment of the present invention.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate a preferred embodiment of the invention, in one form thereof, and such exemplifications are not to be construed as limiting the scope of the disclosure or the scope of the invention in any manner.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The capture shield of the present invention is designed for use within an impingement oven as well as other ovens. Examples of impingement ovens which are compatible with the present invention are found in the aforementioned U.S. Pat. Nos. 4,626,661 and 4,438,572. Referring to FIGS. 1, 2, and 3, capture shield 8 is located on grill rack 10, both of which are attached over baking pan 12. A food item such as a chicken is placed within baking pan 12 and grill rack 10 is placed on the chicken to compress and flatten it. Baking pan 12 is rectangularly shaped with four side walls and an open top. Preferably, the bottom of baking pan 12 has a grooved surface 13 defining ribs 13a and depressions. Grill rack 10 includes a plurality of transverse rods 14 which pivot about an axial rod 16. Connected to both ends of grill rack 10 are hooks 18 which are adapted to latch over retainer 20 of baking pan 12. End aprons 22 of capture shield 8 are adapted to fit closely over end loops 24 of grill rack 10. Alternately, grill rack 10 can be omitted.
In accordance with the present invention, capture shield 8 is provided with a plurality of elongate fins 26. Each fin 26 has a vertical portion 28 and a slanted portion 30. Slanted portions 30 extend from the bottoms 32 of vertical portions 28 downwardly toward the center of baking pan 12. The lower ends 34 of slanted portions 30 of fins 26a and 26b are located about the center of baking pan 12 and are contiguous. All fins 26 have a slanted portion 30 which extends under an adjacent vertical portion 28, excepting fins 26a and 26b. With this structure, a line-of-sight from directly over capture shield 8 to baking pan is blocked (FIG. 3). Alternate capture shield designs are shown in FIGS. 4, 5, and 6. Each design shares the characteristic that a direct vertical path out of baking pan 12 is blocked. FIG. 4 is the design depicted in FIGS. 1-3. Each fin 26 has a vertical portion 28 and slanted portion 30. FIG. 5 is the Bernoulli rod arrangement, with transverse rod 36 having obstructing rods 38 and 40 positioned above and below, respectively. Bottom obstructing rods 38 are spaced apart and extend completely across baking pan 12, with top obstructing rods 40 positioned over the spaces between rods 38. With this arrangement, vertical tangential lines on either side of a top obstructing rod 40 intersect the circumference of a bottom obstructing rod 38. Thus no vertical line-of-sight can extend through capture grill 8'.
FIG. 6 is a V-configuration arrangement, with fins 42 having the shape of a horizontal V. Each fin 42 has a vertex 44, an upwardly slanted portion 46, and a downwardly slanted portion 48. Slanted portions 46 and 48 extend in a horizontal direction toward the center of the baking pan, with each pair of slanted portions 46 and 48 having the vertex 44 of its adjacent fin 42 located within the boundaries of the triangle defined by portions 46 and 48. In the center, middle fins 42a and 42b have a similar contour but are smaller than the other fins 42, and rod 50 is positioned between middle fins 42a and 42b for blocking the direct line-of-sight.
If desired, the grill rack 10 could be omitted and the capture shield 8 could be clamped to pan 12 in order to compress the food product and impart the grill markings on the top of the food product. The fins 26 of shield 8 will be heated by the impinging air and this, in combination with a sugar based glaze, will impart the appropriate grill markings on the food product.
In operation, grill rack 10 is pivoted to open access to the interior of baking pan 12 and food items such as pieces of chicken (not shown) are placed within baking pan 12. Next, grill rack 10 is pivoted over to cover baking pan 12, usually pressing down on the food items inside and latched in place. Once grill rack 10 is securely in position, capture shield 8 is positioned over grill rack 10, with end aprons 22 mating with respective end loops 24. The resulting assembly is placed within an impingement oven, which may be either a moving conveyor surface or a stationary surface.
Once in the impingement oven, jets of hot air are directed into baking pan 12, heating the chicken then recirculating. As the chicken is heated, fat and grease are vaporized and enter the air flow. However, as the air recirculates and leaves baking pan 12, the flow collides with the surfaces of fins 26. The collisions divert the air in the flow, but the heavier suspended fat and grease particles tend to deposit and accumulate on the surfaces of fins 26. Although some fat or grease may avoid fins 26, a great majority of the vaporized fat and grease form droplets. After a period of time, the droplets created by the accumulation start to flow downwardly on the surfaces of fins 26 and drip back onto the chicken, thus basting the chicken with its own drippings. For fat and grease that does not vaporize, the depressions on surface 13 of baking pan 12 provide grease wells which collect the grease between ribs 13a and beneath the chicken.
While this invention has been described as having a preferred design, it can be further modified within the teachings of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention following its general principles. This application is also intended to cover departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
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A splatter capture shield for impingement ovens. The shield has a plurality of elements which are vertically overlapping but not physically touching to allow the jetted air streams of the impingement oven into a baking pan, but not to allow escaping gas with entrained grease to pass through the shield without hitting one of the shield elements. The vaporized grease collects on the shield elements and then drips back down on the food item, thus self-basting the food item.
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BACKGROUND OF THE INVENTION
The invention relates to a device for adjusting the phase angle of a camshaft of an internal combustion engine with a drive gear for driving a camshaft accommodated in a coaxial arrangement relative to the camshaft and with an electric motor for rotating the camshaft relative to the drive gear, wherein the electric motor has two concentrically arranged rotors, of which the one is connected to the camshaft and the other to the drive gear.
To obtain optimum values for fuel consumption and exhaust emissions in different areas of the internal combustion engine's operating characteristics, the valve timing must be varied in dependence of different operating parameters. An elegant manner of varying the valve timing is realized by rotating the camshaft relative to its driving gear. The camshaft of an internal combustion engine is usually driven by a sprocket wheel, which is connected to the crankshaft via a drive chain, or by a drive gear configured as a pulley, which is connected to the crankshaft via a toothed belt.
DESCRIPTION OF THE PRIOR ART
In GB 2 221 513 A a camshaft adjusting mechanism is described wherein an electric motor operates a set of link arms turning the camshaft relative to its driving gear. To this purpose an actuating element carrying the pivoted arms is shifted in axial direction. This solution however involves considerable expense and play on account of the large number of bearings.
In DE 41 10 088 C1 and DE 39 29 619 A1 adjusting mechanisms are described wherein an adjusting element is provided between a member connected to the camshaft and a member connected to the drive gear, which element has two helical threads meshing with corresponding threads of the camshaft or the drive gear. By axially displacing this adjusting element, the camshaft can be rotated relative to its drive gear. Axial displacement of the adjusting element may be obtained by actuating a hydraulic plunger which is operated in dependence of the desired adjustment. The disadvantage of this solution is that the forces required can only be attained with a large hydraulic plunger necessitating considerable constructional expense. Moreover, a comparatively large quantity of oil is required for operating the plunger, which will necessitate a suitably sized pump and thus add to the engine load. As a further drawback of this known type of mechanism, adjustment of the camshaft is possible only between two extreme positions.
An electric adjusting device also is presented in DE 41 01 676 A1, wherein an electric motor is provided for displacing the adjusting element by means of a threaded spindle. As the adjusting element rotates essentially at camshaft speed, an axial thrust bearing must be provided between the electric motor and the adjusting element, which takes up the relative movement between the non rotating and the rotating member. In the above solution, the thrust bearing is more or less permanently subject to load throughout the entire operating period, since the torsional moments acting between drive gear and camshaft will produce a force acting on the adjusting element in axial direction. For this reason the thrust bearing is a critical component which will limit the useful life of the engine. A similar solution is disclosed in DE 33 20 835 A1, wherein the same disadvantages are encountered.
In DE 36 07 256 A a mechanism is described, wherein a stepping motor is provided for adjusting the camshaft, which stepping motor being connected to both camshaft and drive gear. As the stepping motor must take up the entire driving torque for the camshaft, such a solution cannot be achieved within reasonable limits of expense.
This disadvantage is avoided in the adjusting device disclosed in DE 41 10 195 for two structural components connected in their rotating drive, in which an electric motor with a stationary stator is driving a planet carrier supporting a couple of concentric planet gears. Such a stationary electric motor however always has to run during operation, adjustment of the two structural components relative to one another being carried out by faster or slower run. To adjust such a device is complicated.
EP 0 596 860 A discloses a device for adjusting the valve opening times in which the camshaft has a hollow configuration and comprises an inner shaft. The cams are bipartite, wherein each single cam section can be turned relative to the other by a determined angle. The rotation of the two cam sections is executed by a revolving electric motor, which is supplied via slip rings. Similar solutions are disclosed in U.S. Pat. Nos. 5,417,186 and 4,770,060.
A former suggestion of the applicant, published in EP-A 0 903 471 presents an adjusting mechanism for the phase angle of a camshaft with a planetary gear set, in which the adjustment is executed by an electric motor that is supplied with current by means of slip contacts.
Adjusting the phase angle of a camshaft by means of an electric motor proved an advantageous solution in practical operation. To supply the electric motors by means of slip contacts however is the weak point of such devices.
SUMMARY OF THE INVENTION
It is an object of the present invention to avoid these drawbacks and to develop a device as described above in such a manner that slip rings, slip contacts and the like can be omitted.
It also is an object of the invention to have a first coil arrangement non rotatably linked to one of the rotors, said first coil arrangement electromagnetically interacting with a stationary coil arrangement in order to induce or to transmit the energy needed for the operation of the electric motor.
The main point of the invention is that the electric motor that occasions the adjustment of the camshaft is energized without any contact by a coil arrangement. The energy may hereby either be transmitted like in a transformer via an air core or be induced like in a generator. Since the electric motor is a rotating member, the following description will not distinguish stator and rotor of the electric motor, as this is generally the case, but will rather speak of two rotors. One of the rotors is basically connected to the camshaft, whereas the other rotor is connected to the drive gear which may be configured as a sprocket wheel or as a pulley wheel for receiving a toothed belt. Since the driving torque needed to adjust the phase angle of the camshaft is quite big, and since, on the other side, the adjusting angle is quite small, it commonly is necessary to provide a set of gears that converts a relative movement of the two rotors of some revolutions into a rotation of the camshaft relative to the drive gear of approximately 15° to 20°.
In a particularly preferred embodiment of the present invention the set of gears is composed of a rigid, circular hollow gear and of a flexible externally toothed gear, which is accommodated on a roller bearing with an elliptical inner ring that meshes with the hollow gear. Such a gear is commonly called a Harmonic-Drive. As already described above, a quite big step-up ratio is needed between the electric motor and the member it is driving, which may be achieved by such a set of gears. If for example the teeth of the hollow gear amount to 100 and the teeth of the elliptical gear amount to 98, the step-up ratio obtained is of about 1:50. Since this is achieved by a single-stage gear without using planet gear or the like, the device according to the invention may thus be of an extremely compact design.
To have a rotor directly connected to the elliptical inner ring of the roller bearing constitutes a particularly favorable solution in this connection. It is also of advantage when the internally toothed gear has entered a rigid connection with a rotor. Thanks to these measures, a simple and compact layout may be achieved.
The disadvantage of the Harmonic Drives of the art is that they only can be loaded to a limited extent because of their relatively fine teeth. Such gears are particularly sensitive to impulsive loads. In order to avoid this disadvantage, the gear may be made of the following component parts: a first plane of action arranged on the inner periphery of a first engaging part, a second plane of action arranged on the outer periphery of a flexible engaging part and engaging the first plane of action and a driving member arranged coaxially to the first engaging part and to the flexible engaging part, a roller bearing provided with a non circular inner ring being accommodated on said driving member and having a flexible outer ring connected to the flexible engaging part and pushing it by preferably two points against the first engaging part, wherein the first plane of action of the first engaging part frictionally engages the second plane of action of the flexible engaging part.
In such a gear, the evident allocation of the different component parts with regard to the phases and the exact transmission ratio of a toothed gearing is no longer given, but resistance to overload may thus be achieved, which is not possible with a toothed gearing. Furthermore, the gear according to the invention is unaffected by dirt and requires little lubrication.
A further advantage of the invention is that the eccentricity of the wave generator may be considerably smaller than in a toothed gearing of the art. In those traditional toothed gearings, it is necessary to make the eccentricity so big that the teeth of the first and of the second plane of action do not come into conflict outside the engaging areas. In the solution according to the invention, the eccentricity is only defined by the small path needed to establish a frictional engagement. That is why the deformation of the flexible engaging part during operation is considerably smaller, which reduces losses and increases service life.
In principle it is possible to have the first and the second plane of action meshing on one, two, three or more points. It proved particularly advantageous however to provide two opposite engaging points. In such a solution, the inner ring of the roller bearing is essentially elliptical in cross section.
Secure transmission of force may particularly be achieved by giving the first plane of action a conical shape with a small aperture angle. Eventual wear can thus be compensated, too. In this connection, it is particularly advantageous to have the aperture angle amounting to between 1° and 10°, preferably between 2° and 6°. In this case, the wave generator preferably is embodied in such a manner that the outer ring of the roller bearing has got a conical shape with a small aperture angle. The aperture angle of the outer ring should thereby essentially match the aperture angle of the first plane of action.
It is particularly advantageous to provide a pressure means that presses the first plane of action in axial direction against the second plane of action. An independent adjustment of the pressure force and with it of the transmissible torque may thus be achieved. The pressure means preferably is provided with a spring that prestresses the first engaging part and the flexible engaging part against each other in axial direction.
In a particularly preferred variant a rotor of the electric motor is essentially configured as a tube-shaped sleeve that supports on its inner circumference a winding electromagnetically interacting with a winding or with a permanent magnet arranged on the other rotor, the sleeve having on its external circumference a coil arrangement cooperating with a stationary coil arrangement. A particularly simple bearing of the movable component parts is thus made possible. The inner rotor may for example support permanent magnets interacting with windings arranged on the inner circumference of the outer rotor. By feeding the outer rotor with alternate current of an appropriate frequency, the electric motor may be operated like a synchronous machine. In theory, it is also possible to configure the inner rotor as a squirrel-cage rotor and to operate the electric motor as an asynchronous motor. These variants have the advantage that the inner rotor needs not to be fed with external power. Higher efficiency may be achieved however by energizing the inner rotor electromagnetically, too.
The coil arrangements comprise at least one winding each that is essentially accommodated in circumferential direction. Thus, the electric current transmitted by the coil arrangement becomes independent of the camshaft's speed. This is important, since the transmission executed by the coil arrangement not only supplies the power for the operation of the electric motor, but also includes the control data.
In this connection it is particularly advantageous to have the sleeve rigidly connected to the drive gear. The rigid connection is also to be used in case the sleeve is configured integral with the drive gear.
Thanks to the preferred configuration of the inner rotor as a tube-shaped sleeve, the construction of the device and particularly its erection may be considerably facilitated, since the whole adjusting device may essentially be fastened onto the camshaft by means of one single screw.
In another variant of the present invention one rotor is connected to the other rotor via a ribbon cable in order to transmit electric power for the energization of a rotor. In this solution, advantage has been taken of the fact that the two rotors move in opposite direction during only a few revolutions. In this solution, one rotor is fed with power via a coil arrangement. The other rotor is communicating with the first rotor via the ribbon cable. In this connection, it is particularly advantageous to have one rotor fitted with an electronic control unit for evaluating the control signals transmitted through the ribbon cable. In this way, the current needed to supply a rotor may be changed by the control unit, in its frequency for example. It is thus possible to imitate for example the functioning of a stepping motor.
In an alternative variant of the invention the two rotors are each provided with an independent coil arrangement, each of which interacting with a corresponding stationary coil arrangement. Thanks to the independent energization, an independent energization of windings in both rotors may be achieved easily, too.
It also is advantageous to have the first coil arrangement and the stationary coil arrangement configured as a rotary current generator. Electric current may thus be produced in a particularly easy and reliable manner. The current production in this generator depends on the energizing current so that the motor may be driven in a simple way. If need be, a second field winding may be provided, which brings the rotor to slow down in order to also effect in a fast and reliable way a backward adjustment. As an alternative, the current produced by the generator may be phase shifted in a corresponding circuit element before it is fed to the electric motor, which also makes a return of motion possible.
A compact design and a particularly fast response characteristic may also be achieved even at low speed when the stationary coil arrangement is provided with a number of poles which is superior to the one of the rotors of the electric motor. The slip of the squirrel-cage rotor may thus efficiently be compensated.
A preferred variant of the invention has the drive gear communicating with the crankshaft via a frictionally engaged drive. A frictionally engaged drive, for example a V-ribbed belt, is of advantage for being considerably cost-saving. However, the clear phase relation of the drive gear to the crankshaft of the internal combustion engine gets lost. This may be compensated by the adjusting device according to the invention, which offers unlimited adjusting possibilities.
The present invention will be described more explicitly in the following with the help of the embodiments illustrated in the figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal section through a first variant of the invention;
FIG. 1A is a slightly modified variant of the embodiment in FIG. 1;
FIG. 2 is an exploded view of a common Harmonic Drive;
FIGS. 3A, B, C, D are representations intended to explain the way a Harmonic Drive operates;
FIG. 4 to 8 are longitudinal sections or partially axonometric representations in vertical section of further variants of the invention.
FIG. 9, 10 , 11 and 11 A are details of a further variant of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The device of FIG. 1 consists of a camshaft 1 and of a sleeve 2 which is rotatable relative to the camshaft 1 and which has a sprocket wheel 3 configured in such a way that it is integral with it. A gear 6 is connected to the camshaft 1 by means of a screw 4 and a disk 5 , which gear 6 is configured as a thin-walled cylinder terminated at one end by a rigid disk 7 . The screw 4 secures the disk 7 of the gear 6 non rotatably relative to the disk 5 and the camshaft 1 . In the area 8 , the sleeve 2 is configured as a circular, internally toothed gear that engages the gear 6 . By its inner side, the gear 6 props on the outer ring 9 of a roller bearing 10 which is configured as a ball bearing. The inner ring 11 of the roller bearing 10 has got an elliptical shape so that the gear 6 only engages the internally toothed area 8 of the sleeve 2 by two points facing each other in circumferential direction. The number of teeth of the gear 6 is smaller by two than the number of teeth of the internally toothed area 8 that constitutes a hollow gear. The inner ring 11 of the roller bearing 10 is rigidly connected in an inner rotor 12 , which is essentially shaped like a tube. On the opposite end, the rotor 12 is borne on the sleeve 2 via a ball bearing 13 . On its outer periphery, the inner rotor 12 carries a winding 14 interacting with a winding 15 configured on the inner periphery of the sleeve 2 , which constitutes the outer rotor. The windings 14 and 15 are further connected by a ribbon cable 22 that transmits electric current from the sleeve 2 onto the inner rotor 12 . The ribbon cable 22 has got length enough to bridge the potential area of rotation of the rotors 2 , 12 running in opposite directions. An electronic control unit, which is not illustrated in FIG. 1, may be provided to change for example the frequency of the current transmitted to the winding 14 in order to change accordingly the speed of the inner rotor 12 relative to the sleeve 2 .
The electric power for energizing the windings 14 and 15 is obtained by a stationary coil arrangement 16 , which cooperates with a coil arrangement 17 arranged on the sleeve 2 . In order for the current transmission across the air gap 18 to be independent of the speed of the sleeve 2 , the coil arrangements are wound in circumferential direction. Sheet iron 19 is used to reinforce the electromagnetic field.
The sleeve 2 is rotatably borne opposite the housing 20 , which has been only hinted at, and the whole device is closed by a cover 21 . Thanks to the tube-like configuration of the rotor 12 , the complete device except for its cover 21 may be fastened by only screwing in the screw 4 on the camshaft 1 .
Operation of the device of the present invention now will be described more thoroughly. If the adjusting angle of the camshaft 1 cannot be changed, it is actually not necessary to energize the electric motor, since the set of gears 23 consisting of the gears 6 , 8 is self-locking. In order to secure the position, a current may however be transmitted via the coil arrangements 16 , 17 , which keeps the windings 14 , 15 in a stable position relative to one another. In this case, drive gear 3 and camshaft 1 rotate at the same speed. If the phase angle of the camshaft 1 can be adjusted, a motor-actuated control feeds the coil arrangement 16 with an appropriate voltage that is transmitted to the coil arrangement 17 on the sleeve 2 . The current induced therein supplies the winding 15 on the sleeve 2 and, via the ribbon cable 22 and the control unit, the winding 14 on the inner rotor 12 . In the simplest case, the control unit may be configured as a rectifier circuit that feeds the windings 14 with a constant direct current so that the magnetic polarity existing on the periphery of the outer rotor 2 is independent of the frequency of the alternative current transmitted through the coil arrangements 16 , 17 . An alternating current however is applied on the outer winding 15 and produces a rotating electromagnetic field effecting a rotation of the inner rotor 12 relative to the sleeve 2 . Since the gear 6 has two teeth less than the hollow gear 8 , one complete revolution of the inner rotor 12 causes the camshaft 1 to rotate relative to the sleeve 2 to the extent of two teeth. Therefore, the torque that has to be produced on the electric motor only constitutes a small fraction of the actually required adjusting torque.
The variant of FIG. 1A widely corresponds to the one of FIG. 1 . The analogous parts are referred to with the same reference numerals and are not described again in the following. In this variant of an embodiment, screws 25 are screwed in the sleeve 2 in radial direction, said screws engaging into ring segment shaped recesses 40 of the camshaft 1 . The allowable rotating angle of the camshaft 1 is thus defined. This variant also differs from the afore described one by its cover 21 that is pulled over the sprocket wheel 3 and directly fixed to the housing 20 . The drive chain 3 a is illustrated in FIG. 1 A. FIG. 1A also shows the control unit 41 which is supplied by the coil arrangement 17 . The winding 15 on the sleeve 2 is directly energized via the control unit 41 , whereas the winding 14 on the rotor 12 is fed via the ribbon cable 22 . In this variant, the control unit 41 may be formed in such a manner that the control pulses transmitted by pulse-width modulation are used together with the actual driving power for producing two alternating currents in order to energize the windings 14 and 15 . At the same frequency, no rotation takes place and the adjusting angle of the camshaft 1 remains the same. A leading or a lagging movement of the camshaft 1 may be occasioned by an appropriate difference in frequency. Thanks to a Hall detector or the like, which is not illustrated in the drawings herein, it is possible to get some information about the instant adjusting angle of the camshaft 1 . Power supply occurs via connections 28 that communicate with the coil arrangement 16 .
FIG. 2 shows details of a Harmonic Drive in an axonometric exploded view. The inner ring 11 of the roller bearing 10 is elliptic with a slight eccentricity. The outer ring 9 is directly supported by the inner side of a flexible gear 6 . This gear 6 meshes by two opposite points with a rigid, internally toothed gear 8 , which has got a circular shape.
FIGS. 3A, B, C and D show the mode of operation of this Harmonic Drive. In the position shown in FIG. 3B, the inner ring 11 is rotated 90° clockwise relative to the position shown in FIG. 3 A. The FIG. 3C shows a further rotation by 90° and FIG. 3D one complete revolution by 360°. For the sake of clarity, an arrow 11 a was introduced into the FIG. 3A, B, C and D. The number of teeth of the flexible gear 6 is smaller by two than the number of teeth of the internally toothed gear 8 . A small difference in angular velocity between gear 6 and gear 8 arises out of it. As may be seen in the Figures, the sign 6 a that alludes to the gear 6 is moved slowly counterclockwise while the inner ring 11 is turning. As a whole, the rotating angle corresponds to the central angle of two teeth of the gear 6 .
The variant of FIG. 4 only differs from the variant of FIG. 1 by having the winding 14 of the inner rotor 12 supplied via a separate coil arrangement 27 that interacts with another, stationary coil arrangement 26 . Thus, intensity of current, frequency and phase position of the currents in the windings 14 and 15 may be adjusted irrespective of one another. Control may thus be structured with particular degrees of freedom.
It is noted that in cases in which the adjusting torque is small, permanent magnets may be arranged on the inner rotor 12 , said permanent magnets cooperating with a winding 15 on the sleeve 2 . In this way, one pair of coil arrangements feeding the winding 15 on the sleeve 2 may suffice and it is no longer necessary to provide a ribbon cable like in the variant in FIG. 1 or another coil arrangement like in the embodiment of FIG. 2 .
In order to ensure emergency operation in case of failure of the adjusting device, a projection 30 is provided in the sleeve 2 , said projection engaging a peripheral groove of the camshaft 1 so that adjustment is possible in an allowable range only.
In the variant of FIG. 5, the coil arrangements 36 , 37 are arranged in such a way that their front sides are conspiring. The drive gear 3 is configured as a pulley having two engagement surfaces 3 a and 3 b , one of them serving to receive a toothed belt (not shown) driving said pulley via a crankshaft, whereas the other is provided to drive another camshaft (not shown). Furthermore, a recess 38 having the shape of a circular segment is provided in the camshaft 1 , a mating projection communicating with the drive gear 3 engaging said recess in order to limit the motion of rotation. The remaining structure is similar to the one of the afore described variant.
FIG. 6 shows schematically another variant of the invention. A motor winding 44 is rigidly connected to the sleeve 2 , which is rotatable relative to the camshaft 1 and which has an integrated drive gear 3 , so that the sleeve 2 constitutes the rotor of the electric motor. Another rotor of this electric motor is constituted by a short-circuit rotor 45 that communicates with the camshaft 1 via a Harmonic Drive 56 which only is diagrammatically hinted at in FIG. 1 . The Harmonic Drive may be embodied as shown in the FIGS. 2 and 3A, 3 B, 3 C and 3 D or it may be configured as a friction gear of mainly the same structure. The Harmonic Drive 56 has a big transmission ratio of for example 50:1 so that the electric motor only has to provide one fifty est of the adjusting torque of the camshaft 1 . In order to limit the holding load to nearly zero when stationary, a double free-wheel 57 is provided between the short-circuit rotor 45 and the sleeve 2 , said double free-wheel effecting that the drive torque of the camshaft 1 does not produce any torque on the electric motor, so that, when stationary, the electric motor does not have to provide any torque. Further more, a first coil arrangement 58 configured as a generator winding is connected to the rotor, said first coil arrangement also communicating electrically with the motor winding 44 . A stationary coil arrangement 59 induces in the coil arrangement 58 a current that serves to move the short-circuit rotor 45 relative to the motor winding 44 . The speed of the short-circuit rotor 45 relative to the motor winding 44 may be controlled via the current supply 60 of the stationary coil arrangement 59 . Since only an exciting current has to be transmitted to the connection 60 , the electrical supply system of the motor vehicle is hardly loaded by the adjusting device. When the first coil arrangement 58 has got twelve or eighteen poles for example and the motor winding 44 has got six poles, an electrical transmission ratio is created that guarantees a fast adjusting motion of the camshaft even at low speed.
In FIG. 7, the stationary coil arrangement 59 representing the field winding, the first coil arrangement 58 representing the winding of the generator, the motor winding 4 , which is connected mechanically and electrically to the first coil arrangement, and the short-circuit rotor 45 are depicted. In the illustrated variant, the different component parts are placed radially into each other. Any other geometric configuration like for example an axial arrangement with a disk rotor or an arrangement having the electric motor outside the generator may be chosen, when constructional circumstances so require. The short-circuit rotor 45 also may have a conical shape in order to optimize the torque behavior.
FIG. 8 shows schematically how the device according to the invention is built in. A housing 70 covers the camshaft 1 , a cover 71 receives the stationary coil arrangement 59 . A shaft seal 82 seals the adjusting device relative to the cylinder head.
The gear of FIG. 9 consists of a motor shaft 100 provided on its end with a bearing surface 101 on which a roller bearing 102 configured as a ball bearing is wedged up. The roller bearing 102 has an inner ring 103 whose outer periphery is elliptical. The flexible outer ring 105 gets its elliptical shape by the rollers 104 . Since the outer periphery of the outer ring 105 is slightly beveled, the ring as a whole adopts the shape of an elliptical cone. A flexible engaging part 106 sits close to the outer ring 105 . The second plane of action 107 is arranged on the outer periphery of the engaging part 106 , said second engaging part engaging a first engaging part 108 arranged on the inner periphery of a first engaging part 109 . The first plane of action 109 has got the shape of a circular cone. An output shaft 110 is communicating with the engaging part 106 . A thin-walled inner ring of uniform thickness that is fixed on an elliptical bearing surface may be used instead of an elliptical inner ring 103 , so that an elliptical circumferential surface is obtained by resilient deformation.
The way of operation of the device according to the invention is explained more thoroughly in the following. In the position illustrated in FIG. 10, the planes of action 107 and 108 are in contact in the areas 111 and 112 , which are opposite to one another. When the motor shaft 100 rotates, these areas 111 and 112 creep along the first plane of action 108 until they reach their original position. The second plane of action 107 thereby rolls off on the first plane of action 108 . Since the circumference U 1 , of the first plane of action 108 is slightly bigger than the circumference U 2 of the second plane of action 107 , the engaging part 106 rotates slightly in a direction opposite the direction of rotation of the motor shaft 100 . The transmission ratio i, which is defined by the speed of the motor shaft over the speed of the output shaft, corresponds to the reciprocal value of the eccentricity ε, when the latter is defined according to the following equation:
=(U 1 −U 2 )/U 1
Depending on the material chosen, values of i=1/ may be achieved in a range of 100 through 300 and more. Generally speaking, the harder the substances used for the planes of action 107 and 108 , the bigger the transmission ratio may become.
FIG. 11 shows a set of gears according to the invention that is part of an adjusting device for the camshaft of an internal combustion engine, which has not been illustrated in detail. A frictional wheel 206 , configured as a thin-walled cylinder and constituting the flexible engaging part, is fixed to the camshaft 201 by means of a screw 204 . A sleeve 202 having a sprocket wheel 203 integrated to it is rotatable relative to the camshaft 201 . A roller bearing 210 is given an elliptical shape so that the frictional wheel 206 engages an engaging area of the sleeve 202 by only two points located opposite each other in circumferential direction. The circumference of the frictional wheel 206 is slightly smaller than the circumference of the plane of action 208 , which is arranged on a ring 220 that may be displaced in axial direction relative to the sleeve 202 and that is configured as a hollow gear. The inner ring of the roller bearing 210 is rigidly connected in a drive element 212 communicating with an adjusting motor (not shown).
To make sure that the required pressure of the frictional wheel 206 acting against the ring 220 is permanent, a spring 221 is provided that prestresses the ring 220 relative to the sleeve 202 .
In FIG. 11A, an exploded view shows the structure of the above mentioned set of gears. Although the ring 220 is axially slidable in guides 219 on the sprocket wheel 203 , it is non rotatably borne. The drive element 212 is connected to a support 214 for the inner ring of the roller bearing 210 via a ring 213 . The connection is secured by a disk 215 and by a Seeger circlip ring.
The present invention permits creation of an electric motor driven adjustment of the camshaft of an internal combustion engine that has got a particularly simple design and that is particularly robust and long-lived due to the fact that it avoids any slip contacts.
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The invention relates to a device for adjusting the phase angle of a camshaft of an internal combustion engine with a drive gear for driving a camshaft accommodated in a coaxial arrangement relative to the camshaft and with an electric motor for rotating the camshaft relative to the drive gear, the electric motor having two concentrically arranged rotors, of which the one is connected to the camshaft and the other to the drive gear. Simple and safe adjusting is achieved by having a first coil arrangement non rotatably linked to one of the rotors and electromagnetically interacting with a stationary coil arrangement in order to induce or to transmit the energy needed for the operation of the electric motor.
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DESCRIPTION 1. Technical Field
This invention generally relates to rotary compressors and specifically to relief valves for providing refrigerant to prevent damage during reverse rotation of rotary compressors. 2. Background Art
The typical rotary hermetic compressor is configured as typically one of two types. One type is the high side compressor and the other type is the low side compressor. This means simply that the motor which operates the compression portion of the system is disposed in the discharge or high-pressure portion of the hermetic shell, hence being a high-side compressor or that the motor is disposed in the suction or low pressure portion of the hermetic shell, thus being known as a low-side compressor. A common problem with the rotary compressor is the tendency of compressed refrigerant to flow from the discharge portion of the hermetic shell through the compression portion of the compressor system to the suction side of the hermetic shell and hence to repressurize the low-side of the system. This tendency may be eliminated by preventing reverse rotation of the compression portion of the system so that refrigerant may not pass through the compressor to the low-side portion of the hermetic shell.
This is typically accomplished by the inclusion in the compressor system of a check valve such as a reed valve or ball valve to prevent reverse flow of the refrigerant. It is also possible to accomplishe this by the inclusion of a solenoid operated shutoff valve in the refrigerant system to which the compressor is connected.
In a refrigeration system having a compressor which is protected from reverse rotation by a check valve, a separate additional problem arises in the event that the compressor is operated in reverse rotation for some reason such as improper wiring of the driving motor. This problem was recognized in U.S. Pat. No. 4,560,330, directed toward the high side compressor. In the high side compressor, a suction line check valve was included to prevent reverse rotation of the compressor due to pressure differential between discharge and suction line pressure, however, in the event of driven reverse rotation, discharge pressure refrigerant would be pumped from the discharge port to the suction line valve. This results in excessively high pressure tending to breakdown the exterior portion of the wraps in the scroll compressor described in the patent. The solution lay in providing a check valve to release this abnormally high pressure refrigerant to the discharge pressure portion of the hermetic shell.
It is impractical to apply the type of relief valve used in a high-side compressor to a low-side compressor. For example, if the check valve were placed on the suction line of the low-side compressor, refrigerant gas at discharge pressure would fill the entire hermetic shell upon each cessation of compressor operation, due to reverse rotation of the compressor elements. This would require that the entire hermetic shell, including that portion normally at suction pressure, be constructed to withstand discharge pressure refrigerant. This would require an unnecessarily heavy and expansive hermetic shell. Furthermore, in the event of intentional or accidental reverse rotation by reverse action of the motor, the entire hermetic shell could be subject to refrigerant at pressure equal to or exceeding the normal discharge pressure of the refrigerant. This could result in a bursting of the hermetic shell, with possible attendant injury and expense, or alternatively, the necessity of providing an unduly heavy and expensive hermetic shell. Finally, this design would necessitate the pumping down by the compressor of the entire suction portion of the hermetic shell to suction pressure before the check valve would open to admit refrigerant from the suction line, resulting in an unnecessary period of recompression of refrigerant at the beginning of each cycle of operation. This would adversely affect the efficiency of the system, introducing unnecessary time lag into the system response to demand for cooling and an unnecessary cost for recompressing the refrigerant.
Therefore, it is an object of this invention to provide a relief valve for preventing damage to a rotary compressor in reverse rotation.
It is another object of this invention to provide such a relief valve in a low-side compressor.
It is a still further object of the invention to provide such a relief valve as will permit the most economical operation of a low-side compressor.
It is a still further object of the invention to provide such a reverse rotation relief valve as will permit the lightest and most inexpensive construction of a low-side compressor.
It is yet another object of the invention to provide such a relief valve which is simple and economical in assembly, maintenance, and operation.
These and other objects of the invention will be apparent from the attached drawings and the Description of the Preferred Embodiment that follows hereinbelow.
SUMMARY OF THE INVENTION
The subject invention is a relief valve for a low-side rotary compressor which comprises a means for providing refrigerant at suction pressure to the discharge port of the compressor when the compressor is operated in reverse rotation. This is accomplished by the provision of a relief passage having a pressure responsive relief valve installed therein. This relief passage, in the preferred embodiment, is comprised of a body defining a chamber with a first passage extending from the chamber to a source of refrigerant at suction pressure and a second, intermediate passage extending from the chamber to the discharge port. A detached valve element operates within the chamber to cover and close the first passage when discharge pressure refrigerant enters the chamber by way of the intermediate passage and opens to permit the flow of suction pressure refrigerant into the chamber and through the intermediate passage when the pressure differential between the refrigerant in the suction pressure portion exceeds that of the refrigerant in the discharge port. This condition occurs when the compressor is operated in reverse, as the discharge check valve is then closed and the pressure of refrigerant in the discharge port becomes substantially low. In this condition, the relief valve of the subject invention provides oil-entraining refrigerant at suction pressure so that the compressor elements are not deprived of lubrication or the cooling effect of the refrigerant passing therethrough.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a cross-sectional view of a low-side scroll compressor including the preferred embodiment of the subject invention.
FIG. 2 shows an enlarged partial cross-sectional view of the compressor portion of the compressor of FIG. 1.
FIG. 3 shows a cross-sectional view of the compressor of FIG. 2 taken along section line 3--3.
FIG. 4 shows a partial cross-sectional view of the compressor of FIG. 2.
FIG. 5 shows a partial cross-sectional view of the subject invention during normal operation of the compressor as taken along section line 5--5 of FIG. 4.
FIG. 6 shows the relief valve of the subject invention during reverse-rotation of the compressor as taken along section line 5--5 of FIG. 4.
FIG. 7 shows a cross-sectional view of the valve housing of the subject invention as taken through section line 7--7 of FIG. 4.
FIG. 8 shows a cross-sectional view of an alternative embodiment of the subject invention in the compressor of FIG. 2 taken along section line 3--3.
FIG. 9 shows a partial cross-sectional view of the alternative embodiment as taken along section line 9--9 of FIG. 8.
FIG. 10 shows a cross-sectional view of yet another embodiment of the subject invention in the compressor of FIG.2 taken along section line 3--3.
FIG. 11 shows a cross-sectional view of the valve housing of FIG. 10 taken along section line 11--11.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A refrigerant compressor system generally denoted by reference numeral 20 is shown in FIG. 1. Refrigerant compressor system 20 is a rotary compressor housed in a hermetic shell 22. The refrigerant compressor system 20 is not shown in FIG. 1 in detail since details regarding the compressor need not be disclosed to understand the form and function of the subject invention. In actual application of the subject invention, a scroll-type refrigerant compressor system is used. It is understood that a rolling piston or other rotary compressor would be equally suitable for application of the subject invention.
Reference may be had to U.S. Pat. Nos. 801,182; 3,924,977; 4,082,484 and 4,415,318, for a more complete discussion of the scroll-type fluid apparatus, its principles of operation and particulars of construction.
Disposed within the hermetic shell 22 is a fixed scroll 24 having a centrally located aperture defining a discharge port 26. An orbiting scroll 28 is disposed in a parallel spaced relationship with respect to the fixed scroll 24. A fixed involute wrap 30 is disposed on the fixed scroll 24, and an orbiting involute wrap 32 is disposed on the orbiting scroll 28 such that the respective involute wraps are in interleaving engagement definig a plurality of pockets having volume decreasing toward the center of the respective wraps. A swing-link mechanism 34 provides for compliant orbital non-rotating motion of the orbiting scroll 28.
The fixed scroll member 24 further serves to divide the hermetic shell 22 into a discharge pressure portion 36 and a suction pressure portion 38. It is to be understood that the division of the hermetic shell 22 into the discharge pressure portion 36 and the suction pressure portion 38 could be accomplished in the rotary compressor by other means such as an independent barrier member, and that the use of the fixed scroll member 24 is not to be taken as limiting. A suction port 40 is provided to admit suction pressure refrigerant to the suction pressure portion 38 of the hermetic shell 22, and a discharge port 42 is provided to remove discharge pressure refrigerant from the discharge pressure portion 36 of the hermetic shell 22
The refrigerant compressor system 20 is driven by an internal electric motor 50 disposed within the suction pressure portion 38 of the hermetic shell 22. The electric motor 50 includes a stator 52 and a rotor 54. A drive shaft 56 passes through the rotor 54, with its lower end extending into a reservoir of oil 58. Disposed at the lower distal end of the drive shaft 56 is a centrifugal oil pump 60 operative to cause oil 58 to flow upward through an internal bore 62 within the drive shaft 56. The oil thus forced upward through the internal bore 62 lubricates surfaces subject to friction within the compressor system 20 such as the lower drive shaft main bearing 64. The drive shaft bearing 64 is supported in a framework 66 which is attached to the hermetic shell 22 and includes other bearings and structure necessary to support the orbiting scroll member 28. The oil pump 60, motor 50, components of the motor 50 and the structures for supporting the motor 50 are not disclosed in detail, as they are believed to be generally understood in the art. It is understood, for example, that oil pump 60 would be equally suitable if a gear-type or similar pump were used.
The refrigerant compressor assembly 20 further includes means for preventing a backflow of refrigerant from the discharge pressure portion 36 into the discharge port 26 when the pressure of refrigerant in the discharge pressure portion 36 exceeds the ressure of refrigerant in the discharge port 26 Perferably this is accomplished by a compressor discharge valve assembly 100, which is generally shown disposed atop the fixed scroll member 24 adjacent the discharge port 26. This discharge valve assembly 100 may be a ball-type valve, a pressure relief valve, or other suitable valve.
Preferably, the discharge valve assembly 100 is comprised of a valve stop member 120, two guide collars 130, and a detached valve element 140 operating between a closed position and an open position. In the open position, the valve element 140 rests against the valve stop member 120, thus permitting refrigerant to flow from the discharge port 26 to the discharge pressure portion 36 of the hermetic shell, while in a closed position the valve element 140 coveringly seals the discharge port 26 to prevent a flow of refrigerant from the discharge pressure portion 36 into the discharge port 26. As will be described more fully herein, the valve element 140 assumes the closed position under either of two conditions, the first being the inoperative stae of the compressor, and the second being the reverse rotation operation of the compressor.
A relief valve assembly 200 as in the preferred embodiment of the subject invention is shown disposed on the upper surface 190 of the fixed scroll member 24. The relief valve assembly 200 is comprised of a valve containment member or relief housing 220 and a relief valve element 240. The housing 220 cooperates with the upper surface 190 to define a relief chamber 210 wherein the relief valve element 240 operates to freely move between an open position and a closed position in response to any pressure differential acting upon the valve element 240.
A bore having a first end disposed in the suction pressure portion 38 of the hermetic shell 22 and a second end disposed in the relief chamber 210 defined by housing 220 and upper surface 190 constitutes a first, suction pressure source passage, 260 enabling a flow of refrigerant from the suction pressure portion 38 to the relief chamber 210. A second, intermediate refrigerant flow passage 270 is defined by a bore having a first end in the relief chamber 210 defined by the relief housing 220 and upper surface 190, and a second end flowably intersecting the aperture defining the discharge port 26 of the fised scroll member 24.
The relief housing 220 is secured to the fixed scroll member 24 in the preferred embodiment by two guide bolts 250 which extend through suitable guide bolt apertures 222 in the relief housing 220. The preferred location of the guide bolts 250 is most readily apparent in FIGS. 3 and 4. The guide bolts 250 are disposed at opposite sides of the relief housing 220 to accommodate the relief valve element 240 therebetween, thereby serving the dual purpose of guiding the relief valve element 240 between the open and closed position while simultaneously positionally securing the relief housing 220. The guide bolts 250 limit the travel of the relief valve element 240 to prevent misalignment and ensure proper sealing of the relief valve element 240 over the aperture in the upper surface 190 defining the second end of the suction pressure source passage.
In the preferred embodiment, the guide bolts 250 include smooth guide portions and threaded end portions extending into suitable threaded apertures (not shown) in the fixed scroll member 24. It will be apparent to those skilled in the art that the relief housing 220 may be secured to the upper surface 190 by such means as welding and, likewise, that the guide bolt holes 222 could be threaded to accommodate a mating threaded portion of the guide bolts 250, and that it would not be necessary to provide apertures in the fixed scroll member 24 in alternative embodiments.
The relief housing 220, as generally shown in FIGS. 1-7, is comprised of a generally rectilinear body with a downwardly extending wall portion 224 extending about the terminal end of the housing 220. The wall portion 224 extends to a wall end 226 which is planar for sealing engagement with the planar upper surface 190. In the preferred embodiment, no separate seal is required between the housing 220 and the upper surface 190, however, it will be apparent to those skilled in the art that a suitable elastomer seal or a sealing material such as a suitable caulk could be disposed therebetween to further enhance the sealing effect if desired.
A cavity which when the housing 220 is secured by bolts 250 to the upper surface 190 comprises the relief chamber 210, is defined withing the relief housing 220 by a generally planar inner surface 228 and the downwardly extending wall 226. The inner surface 228 is generally parallel to the upper surface 190 of the fixed scroll member 24, and includes a plurality of relief valve engaging protuberances 230. The protuberances 230 serve to stop the relief valve element 240 in the open position. In the preferred embodiment, there are three such protuberances 230 in parallel disposition, each such protuberance 230 being rectilinear in shape. Although these protuberances 230 are shown perpendicularly disposed with respect to the long access of the relief valve element 240, they could equally well be disposed in parallel orientation with respect to this axis. Futhermore, these protuberances 230 need not be rectilinear in shape, but may be downwardly extending dimples of hemispheric or conical shape.
The relief valve element 240 preferably is a substantially thin, planar element having oppositely disposed ends 244, each comprised of two hemispheric lobes 245 with an arcuate portion 246 of a circle defined therebetween for closely fitting about the guide bolt 250. The radius of the arcuate portion 246 of the end 244 is sized to provide a clearance of several thousandths of one inch between the valve element 240 and the guide bolts 250, for free movement of the relief valve element 240. The dispostion of the valve element 240 in the relief valve assembly 200 is depicted in FIGS. 2 through 6.
In operation, the electric motor 50 is energized causing the rotor 54 and the drive shaft 56 to rotate. This rotation is translated by the swing-link mechanism 34 to cause orbital non-rotating movement of the orbiting scroll member 28 with respect to the fixed scroll member 24. The interleaving fixed involute wrap 30 and orbiting involute wrap 32 thus generate a plurality of pockets of decreasing volume from the radially outer ends of the respective wraps toward the center of the respective wraps.
During the operation of the electric motor 50, refrigerant gas is drawn into the suction pressure portion 38 through the suction port 40 from the refrigeration system (not shown). The refrigerant gas then circulates through the components of the electric motor 50 and entrains in the refrigerant gas flow a portion of the oil in the reservoir of oil 58. The oil entraining refrigerant is then compressed in the plurality of pockets defined by the interleaving wraps of the respective scrolls and ejected through the discharge port 26. The ejected oil entraining refrigerant gas forces the valve element 140 to the open position, permitting the now discharge pressure refrigerant to be exhausted to the discharge pressure portion 36 and returned to the refrigeration system through the discharge port 42.
A portion of the discharge pressure refrigerant enters the second, intermediate passage 270 and flows therethrough to fill the relief chamber 210 defined in the relief housing 220 with refrigerant at discharge pressure. As the refrigerant in the first passage 260 is at suction pressure, the relief valve element 240 is forced by the weight of gravity and the pressure differential between the discharge pressure refrigerant and the suction pressure refrigerant to the closed position. In this position, the relief valve element 240 sealingly covers the first passage 260, preventing flow of refrigerant therethrough.
Upon de-energization of the electric motor 50, the valve element 140 immediately moves to a closed position, whereby the valve element is disposed about the discharge port 26 in a covering, sealing manner. This prevents a backflow of refrigerant from the discharge pressure portion 36 into the discharge port 26. The discharge pressure refrigerant may force some slight reverse rotation of the orbiting scroll member 28 until the refrigerant pressure in the discharge port 26, second intermediate passage 270 and relief chamber 210 in the housing 220 is reduced to a point where it is insufficient to cause reverse rotation, however, the volume of refrigerant therein is substantially small. In this state, both the valve element 140 and the relief valve element 240 remain in the closed positions due to the action of the pressure differential upon the respective valve elements in combination with the action of gravity upon the valve element mass.
In the event of accidental or intentional reverse rotation of the orbiting scroll member 28 with respect to the fixed scroll member 24, the fixed wrap 30 and the orbiting wrap 32 function as expanders, removing refrigerant from the discharge port 26. The pressure of refrigerant in the discharge port 26 is reduced below that of refrigerant at suction pressure, and refrigerant is drawn from the second, intermediate passage 270 and the relief chamber 210. As the refrigerant is withdrawn therefrom, the pressure of refrigerant in the relief housing 220 is reduced below that of the refrigerant at suction pressure. The pressure of refrigerant in the first passage 260 then exceeds that of the refrigerant in the relief chamber 210, thereby forcing the relief valve element 240 to the open position along the guide bolts 250 to engage the protuberances 230. The refrigerant thus entering the relief chamber 210 in the housing 220 from the first passage 260 flows through the housing 220 and the second intermediate passage 270 into the discharge port 26, supplying refrigerant to the scroll wraps 30 and 32. This oil entrained refrigerant provides lubrication to the wraps to prevent damage due to lack of lubrication, in addition to providing a source of refrigerant to prevent breakdown of the wraps 30 and 32 due to excessively low pressure at the inner ends thereof.
An alternative embodiment of the relief valve assembly 200a is shown in FIGS. 8 and 9, disposed on the upper surface 190a of the fixed scroll member 24a. As in the preferred embodiment, the relief valve assembly 200a is comprised of a housing 220a cooperating with the upper surface 190a to define a relief chamber wherein a relief valve element 240a operates between an open and a closed position. The relief housing 220a is secured to the fixed scroll 24a by two guide bolts 250a which extend through suitable guide bolt apertures 222a in the relief housing 220a. Two coil springs 280a are disposed in the relief housing 220a, each spring 280a being coaxially disposed about a respective guide bolt 250a between the relief valve element 240a and the relief housing 220a. Alternatively, a leaf spring 280a or a single coil spring 280a mat be disposed between the guide bolts 250a. The springs 280a acts to bias the relief valve element 240a to the closed position. Preferably, the springs 280a have a small spring constant k to provide a minimal biasing force while causing the relief valve element 240a to move rapidly to the closed position in response to changes in the refrigerant pressures.
In operation, this alternative embodiment is similiar to that of the preferred embodiment, however, the springs 280a cause the relief valve element 240a to remain in or return to the closed position whenever the refrigerant pressure in the discharge port 26a in combination with the pressure by the spring 280a on the relief valve element 240a exceeds the refrigerant suction pressure.
In another alternative embodiment shown in FIGS. 10 and 11, the relief housing 220b includes integral guide portions 225b disposed in the relief chamber. The guide portions 225b are integral with the downwardly extending wall 244b, being coplanar with the wall end surface 226b, and with the inner surface 228b. Preferably, the guide portions 225b are semi-cylindric, having an axis parallel to the axis of guide bolt holes 222b extending through the relief housing 220b. This alternative embodiment is, in operation, identical to the preferred embodiment. However, this alternative embodiment does not require the use of guide bolts 250b, but may use standard threaded bolts or may be secured by welding epoxy to the fixed scroll member 24b, and hence may be more economical of manufacture in large quantities.
Preferably, the componenets of the relief valve assembly 200 are formed of suitable steel alloy. While it is possible that the relief housing 220 may be a machined component in its entirety, the housing 220 is preferably forged, cast, or formed from powdered metal and the guide holes 222 and the wall end 226 machined by drilling or milling, as appropriate. The relief valve element 240 is preferably formed by die-press operations, although the relief valve element 240 may be formed by casting or forging if desired.
Additionally, in the preferred embodiment, the first passage 260 is formed at an angle of 55° from the vertical and the second passage 270 is formed at an angle of 37° from the vertical. It is readily apparent that these angles may be changed within a reasonable range, provided only that the ends of the respective passages are disposed to accomplishe the proper flow.
The subject invention provides a simple and inexpensive means for preventing damage to the compressor when operated in reverse rotation either accidentally or intentionally. Furthermore, the subject invention offers the advantage of requiring little or no adjustment or maintenance. Additionally, the subject invention in its preferred embodiment is virtually immune to failure due to fatigue, as there are no elastomeric or other components required to flex or bend and thus fatigue. Finally, the subject invention adds little weight to the compressor system and is not detrimental to the operating efficiency of the compressor system.
Modifications to the preferred embodiment of the subject invention will be apparent to those skilled in the art within the scope of the claims that follow herein.
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In a rotary compressor, a relief valve for providing refrigerant at suction gas pressure to the discharg port when the rotary compressor is operated in the reverse rotation direction. The relief valve includes in the preferred embodiment a passage for providing a source of refrigerant at suction pressure, a pressure responsive relief valve, and a passage for providing refrigerant at suction pressure from the relief valve to the discharge port. When the compressor system is operated in the correct rotation, refrigerant at discharge pressure maintains the relief valve in the closed position, preventing flow from the discharge port to the suction pressure source. When the compressor system is operated in the reverse rotation however, the pressure in the discharge port is reduced to below that of the refrigerant in the suction pressure source, whereupon the releif valve opens permitting flow from the suction pressure source to the discharge port. This thereby provides a source of refrigerant to the compressor to prevent damage to the compressor system during the reverse rotation period.
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[0001] This application is a complete application claiming the benefit of provisional application Ser. No. 60/855,399, filed Oct. 31, 2006.
FIELD OF THE INVENTION
[0002] The present invention includes a tool to aid a plumber in working with faucet connections by the use of a set of sockets sized to fit the nuts generally associated with faucet and water line connection.
BACKGROUND OF THE INVENTION
[0003] Installation of faucets, whether in a kitchen, bathroom, utility room or other location, usually involves the securing of the faucet at the rear of a sink rim or sink basin. With the faucet water connections being located below a counter top or sink level, the area within which the water connections are made is often limited and difficult to access.
[0004] Due to space constraints, it is difficult to provide the lateral swinging motion of a wrench required to initially anchor the faucet on a counter top or on top of a sink rim by securing a washer, usually plastic, around a threaded pipe of the faucet protruding through the counter top or sink lid.
[0005] After securing the washer and thereby the faucet in place, water connections are made by flexible water connection lines between a water shut off valve and the intake to the sink hot and cold water lines. All of these connections are usually made in limited sight areas and even more limited lateral wrench movement areas.
SUMMARY OF THE INVENTION
[0006] Accordingly, it is an object of the present invention to easily secure a nut to anchor a sink in a fixed location and to connect two water lines to the faucet, all performed in a limited space with a single tool.
[0007] This object is accomplished by the present invention through the use of a single elongated pipe having a plurality of grip bars projecting from an exterior surface to assist in grabbing, holding and twisting of the pipe. The pipe has two integral sockets at opposite ends of the pipe.
[0008] One socket at one end of the pipe is hexagonal and the other socket at the other end of the pipe is round with twelve slots. The two sockets are formed at opposite ends of a single, unitary, approximately 1.75 inch outer diameter, PVC or ABS plastic pipe. The pipe is approximately 12 inches long.
[0009] The pipe allows passage through its hollow interior of a water supply line. Each of the ends of the pipe performs a different function for anchoring a faucet and connecting a water supply line. The pipe is reversible to take off or tighten a faucet connection and a water line connection.
[0010] The hexagonal socket includes an internal taper terminating in at least one stop pin to provide a tight fit on a hexagonal water line connecting nut. A stop ledge formed of the at least one stop pin prevents a nut from passing through the socket.
[0011] At the opposite end of the pipe, the equidistant twelve spaced slots accommodate projecting flanges of a plastic nut used to anchor the faucet to a support surface. The flanges of the nut are typically spaced at 30 degrees (12 flanges), 60 degrees (6 flanges), 90 degrees (4 flanges), 120 degrees (3 flanges), or 180 degrees (2 flanges).
[0012] Accordingly, for installation of a sink, the multi-slotted end of the tube is passed over a hand tightened water line to be extended between a shut off valve and the water inlet connection of a hot or cold water connection for the faucet. A nut surrounding the threaded inlet of the faucet has its flanges engage with the slots of the pipe and, by rotation of the pipe, the nut draws the escutcheon plate of the faucet onto either the rim of the sink or the counter top to which the faucet is to be secured. Continued rotation of the pipe secures the nut in tight contact with the under surface of the counter top onto which the sink is mounted.
[0013] The pipe is then retracted and reversed and threaded over the flexible water line to engage the nut that secures the water line to the hot or cold water inlets of the sink. The nut of the water line connection is received in the hexagonal shaped end of the pipe and prevented from passing through the hollow interior of the pipe by at least one stop pin. The pipe is then rotated to secure the connection of the water line to the inlet of the hot and cold water lines of the faucet. The pipe is then retracted over the water line and the free end of the flexible water line is connected to the hot or cold water supply line.
[0014] Accordingly, it is an object of the present invention to provide a single integral pipe having a socket at each of its two ends.
[0015] It is another object of the present invention to provide a single integral pipe having a socket at each of its two ends with one of the sockets including twelve slots for accommodating spaced flanges of a plastic nut at 30 degree, 60 degree, 90 degree, 120 degree or 180 degrees of separation.
[0016] It is still yet another object of the present invention to provide a single integral pipe having a socket at each of its two ends with one of the sockets including twelve slots for accommodating spaced flanges of a plastic nut at 30 degree, 60 degree, 90 degree, 120 degree or 180 degrees of separation with the opposite end of the pipe including a hexagonal shaped opening for engaging, but preventing from passing through, a nut connecting a flexible water line connection to a water line inlet of a sink.
[0017] It is still yet another object of the present invention to provide a single integral pipe having a socket at each of its two ends with one of the sockets including twelve slots for accommodating spaced flanges of a plastic nut at 30 degree, 60 degree, 90 degree, 120 degree or 180 degrees of separation with the opposite end of the pipe including a hexagonal fitting for engaging, but preventing from passing through, a nut connecting a flexible water line connection to a water line inlet of a sink with the exterior of the pipe including semi-circular grip bars for assisting in grabbing and rotating of the pipe.
[0018] These and other objects of the invention, as well as many of the intended advantages thereof, will become more readily apparent when reference is made to the following description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The following drawings illustrate examples of various components of the plumber's wrench disclosed herein, and are for illustrative purposes only. Other embodiments that are substantially similar can use other components that have a different appearance.
[0020] FIG. 1 is a perspective view of the plumber's pipe wrench of the present invention.
[0021] FIG. 2 is a top view of the plumber's wrench.
[0022] FIG. 3 is a bottom view of the plumber's wrench.
[0023] FIG. 4 illustrates the use of two plumber's wrenches to secure a faucet to a rim of a sink with the left hand plumber's wrench engaging and tightening a nut on a threaded portion on the cold water inlet, and the right hand wrench securing a flexible water line to the water inlet of the hot water connection for the faucet.
[0024] FIG. 5 is a partial sectional view illustrating the engagement of the nut at the end of the flexible water line connection which is secured to a water inlet line of the faucet.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] In describing a preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to 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.
[0026] With reference to the drawings, in general, and FIGS. 1-3 , in particular, a plumber's wrench embodying the teachings of the subject invention is generally designated as 10 . With reference to its orientation of FIG. 1 , the wrench includes a single unitary tube 12 made of PVC or ABS plastic.
[0027] The tube has an outside diameter of approximately 1.75 inches and an interior diameter of approximately 1.375 inches. The overall length of the pipe is approximately 12 inches.
[0028] The pipe has two opposite ends 14 and 16 . Extending between the opposite ends are a plurality of equi-spaced semi-circular grip bars 18 extending from end 16 to within approximately one inch of end 14 . The bars have a height of approximately 0.1 inches.
[0029] End 14 is tapered from a portion of the pipe including the bars 18 over approximately one inch of the terminal end of the pipe to decrease its outer diameter to approximately 1.3 inches. End 14 has an interior hexagonal shaped opening 20 with a separation distance between opposite faces of the hexagonal shaped opening 20 of approximately 0.906 inches.
[0030] Projecting radially inwardly from an interior surface of the pipe are two stop pins 22 which prevent passage through the interior of the pipe of a hexagonal shaped nut normally used to connect a flexible water line to a water inlet of a faucet. Alternatively, instead of two stop pins 22 , a ledge extending radially inwardly from the interior of the pipe forms at least a portion of a circle to similarly engage a nut supported above the ledge for engagement with the side walls of the hexagonal shaped opening 20 .
[0031] At opposite end 16 , a plurality of slots 24 having a width of approximately 0.156 inches (approximately 5/32 inches) and a height of approximately ½ inch are cut from the pipe 12 . The dimensioning of the slots is such as to engage the flanges of a nut used to secure a faucet to a support surface.
[0032] In FIG. 4 , a faucet 30 is mounted on a counter top 32 by the use of the plumber's wrench of the present invention. In this Figure, two wrenches are shown as a demonstration of the functions that may be accomplished by a single plumber's wrench of the present invention, reversed for two different functions.
[0033] On the left hand side of FIG. 4 , the plumber's wrench 10 is used with end 16 engaging a nut 34 by having its flanges 36 being engaged in the slots 24 formed at end 16 . Movement of the wrench 10 in the direction of arrow 38 engages the flanges and by rotation of the pipe in the direction of arrow 40 , tightens or loosens the nut 34 to draw the faucet into tight contact with the counter top.
[0034] On the right hand side of FIG. 4 , the wrench 10 has been reversed so that end 14 has been passed over flexible water line connection 42 . A nut 44 is engaged in end 14 .
[0035] The flexible water line connection 42 passes through the hollow interior of the wrench 10 and between the stop pins 22 until the nut 44 is retained by the stop pins 22 for at least a loose fit of the sidewalls of the nut 44 with the sidewalls of the hexagonal opening 20 in end 14 . Movement of the wrench in the direction of arrow 46 tightens or loosens the nut 44 on a water inlet to the faucet 30 .
[0036] As shown in greater detail in FIG. 5 , the nut 44 is shown engaged in the end 14 of the wrench 10 for engagement, holding and rotation with the wrench. The flexible water line 42 passes through the interior of the hollow wrench so as long as the nut 44 is initially threaded onto a water inlet line of the faucet, the wrench may be slid along the flexible water line 42 and into engagement with the nut 44 even without visual confirmation, for subsequent rotation of the wrench and tightening of the nut 44 .
[0037] The foregoing description should be considered as illustrative only of the principles of the invention. Since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and, accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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A single tool easily secures a nut to anchor a sink in a fixed location and to connect two water lines to the faucet, all performed in a limited space. The use of a single elongated pipe having a plurality of grip bars projecting from an exterior surface assists in grabbing, holding and twisting of the pipe. The pipe has two integral sockets at opposite ends of the pipe.
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BACKGROUND OF THE INVENTION
This invention relates to an improved extruder and more particularly to a new and improved extruder screw for plasticizing plastic materials such as polyurethanes.
The mixing and working of plasticizing materials with extruder screws have been directed to increasing their efficiency by improving the overall efficiency of the screw design for general purpose work. The design changes have been generally in the flight configuration or pitch design. To increase the working of the plastic material, improvements have been directed to leading off the fluent material as well as to providing a series of mixing pins to provide a more thorough mixing. The present invention is directed to providing a novel means for increasing shear while simultaneously increasing heat transfer and altering the flow pattern to enhance mixing and to reduce temperature fluctuation across the screw channel which improves the quality and quantity of the mixed product.
SUMMARY OF THE INVENTION
The present invention is directed to a new and improved screw design that has a series of flights which cooperate with a plurality of axially spaced shear rings, which rings have slits throughout the circumference thereof. The slits extend from the periphery of the ring to the root of the screw channel. The slits in the rings provide a restriction to the flow of the material being worked which increases the shearing action and improving the processing of the unmelted particles which are thus sheared into smaller particles. This action increases the heat generated and improves the heat transfer to the material being processed, thereby providing a much more uniform temperature profile than heretofore obtained within the melt.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of an extruder screw showing flights having a plurality of axially spaced shear rings.
FIG. 2 is a cross sectional view taken along line 2--2 of FIG. 1 with a portion of the shear ring shown in full.
FIG. 3 is an enlarged front fragmentary view of a portion of the extruder screw with a portion of the shear ring in full.
FIG. 4 is an enlarged fragmentary cross-sectional view showing a portion of one of the shear rings with the fins in full, similar to FIG. 2.
FIG. 5 is an enlarged fragmentary cross-sectional view showing a portion of a second shear ring with the fins in full.
FIG. 6 is an enlarged fragmentary cross-sectional view showing a portion of a third shear ring with the fins in full.
DETAILED DESCRIPTION
Referring to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a feed screw 4 having a flight 5 of constant pitch, although other types of flights, such as dual flights, and other pitches may be used. The diameter of the core 6 of the extruder screw is shown as of uniform dimension, however, it is contemplated that the invention may be applied to cores of varying diameters. The flight 5 has a leading edge 7 and a trailing edge 8.
Axially spaced along the length of the extruder feed screw 4 are a plurality of shear rings 10, 11 and 12. The shear rings are identical in construction except that their axial length and the dimension of the slits in the respective shear rings are different, accordingly only one shear ring will be described. Shear ring 10 has a plurality of radially extending fins 15 that extend radially outwardly from the core 6 of the extruder. Each fin 15 has a pair of side portions 16 such that a pair of adjacent fins define a groove 17 between adjacent side portions 16. Groove 17 extends radially outwardly from the outer surface of the core 6 of the feed screw 4 to the peripheral surface of the shear ring 10.
The axial lengths of the respective fins 15 or the grooves 17 of the respective shear rings 10, 11 and 12 are longer as one goes towards the forward end or torpedo end of the feed screw. It is contemplated that these lengths of the fins 15 may be constant for the different rings, however, in the processing of materials that is not highly heat sensitive, it has been found desirable to increase the axial length of the fins which in turn increases the length of the respective grooves 17.
Another variable in the respective shear rings 10, 11 and 12 is to make the width of the respective slits decrease in size as one moves in the forward direction of the feed screw. The progressive reduction in size of the openings in the shear rings or the reduction in width of the slits 17 progressively increases the shear as well as heating of the compound being processed.
In the operation of the extruder feed screw 4, the material being processed moves up the channel of the feed screw by the interaction of the flight 5 on the material and as the material reaches the first shear ring 10, the material is forced therethrough by the pressure exerted from the following material due to the rotation of the screw and its flights. As the material is moved through the slits 17, the unmelted particles of the material being processed is sheared into smaller particles. The frictional heat generated by such action aids in the melting of the unfluxed particles. With such shear rings, the flow pattern is altered thereby enhancing mixing and reduces temperature fluctuation across the channel. With the slits smaller as one moves towards the forward portion of the feed screw 4, the amount of heat generated can be increased. The amount of frictional heat generated is proportional to the number of slits and a large number of slits can be installed in a given section of a screw to enable it to generate a controlled amount of heat which can be transferred efficiently to the plastic materials minimizing temperature fluctuation of the material being processed because the thickness of the plastic film in the slits is very thin providing effective heat transfer. It has been found that not only the width and length of the slit openings affect the quality of the extrudate, but also the number of shear rings in a given screw affect the final quality of the extrudate. As an example, an extruder feed screw having a 21/2 inch diameter screw with a length of 24:1 L/D, three slit rings are very effective to increase quantity and quality of mix by having the slits of the first ring four hundredths of an inch, with the slits of the second ring 35 thousandths of an inch, and the slits of the third shear ring being 25 thousandths of an inch.
Various modifications are contemplated and may obviously be resorted to by those skilled in the art without departing from the described invention, as hereinafter defined by the appended claims, as only a preferred embodiment thereof has been disclosed.
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An extruder screw having an elongated core with helical flights with a plurality of axially spaced shear rings along the length thereof. The shear rings have radial slots that extend axially through the shear rings. The length and width of the slots vary in dimension.
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CROSS REFERENCE TO RELATED APPLICATION
This application is a Divisional application of Ser. No. 08/341,675, filed Nov. 17, 1994, now U.S. Pat. No. 5,503,022, dated Apr. 2, 1996, which was a Continuation-In-Part application of Ser. No. 08/253,972, filed Jun. 3, 1994, now U.S. Pat. No. 5,445,012, which was a Continuation application of Ser. No. 08/008,474, filed Jan. 25, 1993, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of the invention relates to engines for boats, and more particularly, to a new and improved method of determining if the water impeller, which is located in the drive unit, of a marine engine, and which pumps coolant water to the engine from the body of water on which the boat or watercraft is disposed, is functioning properly.
The impeller tester provides for the measurement of the inlet and outlet water pressures. These pressures are measured and transmitted through a calibrated gauge or calibrated transducers and lamp modification to indicate to the operator if the water impeller has adequate water supply and if the water impeller is functioning properly.
2. Description of the Prior Art
While various devices and components have been utilized in the prior art in allowing the marine engine to be started and run out of water, they have not communicated if the water impeller in the out drive unit is functioning properly.
Prior state of the art devices are only designed to supply water to the marine engine's drive unit. These devices allow for a method to attach a standard garden hose from a faucet to the drive unit. The amount of water supplied from the faucet is not monitored by these devices and only allows that water be supplied to the marine engine by the water pressure which is available within the municipal water system. A fault of these water supply systems is that they do not indicate if sufficient water pressure is being supplied to safely run the engine, without damaging the water impeller, nor can they determine if the water impeller which is located in the drive unit is functioning and capable of pumping non-pressurized water to the marine engine. These devices thereby will allow the engine to function correctly and not over heat when tested out of the water even though the water impeller in the drive unit has failed and is no longer capable of pumping ambient water (unpressurized) to the marine engine when the watercraft is put in actual service.
As such, it may be appreciated that there continues to be a need for a new and improved method to monitor water pressures both while supplying water to a marine engine when being tested out of water and while the craft is in actual service.
The testing of the boat or watercraft's marine engine is done out of water in order to determine if the marine engine is operating properly prior to taking it to an area intended for watercraft use.
Prior art testing devices allow water to be supplied to the marine engine but do not communicate whether or not the drive components are functioning properly. This is due to the water being supplied under pressure. Water supplied under pressure will supply the engine with sufficient coolant so that it appears to be functioning properly even though the water impeller has failed and will not supply water to the marine engine when the watercraft is put in actual use.
U.S. Pat. No. 2,100,754 (Seegers) discloses a pressure gauge which includes a dual gauge, with one portion of the dial graduated for vacuum pressure and a second portion for positive pressure readings. The dial is adjustable to provide a desired zero reference.
U.S. Pat. No. 2,227,514 (Seegers) discloses another type of pressure gauge in which the dial is also calibrated for vacuum pressure and for positive pressure. The dial is adjustable to provide a desired zero reference.
U.S. Pat. No. 2,247,102 (Sugden et al) discloses a pressure gauge having an adjustable dial.
U.S. Pat. No. 3,969,931 (Lanning) discloses tester apparatus for testing the hydraulic capabilities of an outboard drive assembly.
Italian patent 277,473 (Drager) discloses the coupling of a gauge to a fluid line.
Italian patent 546,083 (Malakoff) discloses the use of a pressure gauge between threaded ends for insertion into a fluid line.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known methods of supplying water to a marine engine while being tested out of water, the instant invention provides an impeller tester which communicates to the operator that there is sufficient inlet water pressure available and correct outlet vacuum pressure induced by the water impeller when the unit is tested out of water. This is necessary if an individual is to insure that the marine engine will be supplied with sufficient coolant when the water impeller is not being supplied with pressurized coolant from a household faucet. As such, the general purpose of the instant invention, which will be described subsequently in greater detail, is to provide a new and improved method of supplying pressurized coolant to a marine engine and which has all the advantages of prior art and none of the disadvantages.
The marine engine, both inboard and outboard types, is equipped with a drive unit. This out drive unit not only incorporates the means to propel the craft by the rotation of a propeller, but also incorporates a water impeller which provides the means to pump water to the marine engine's cooling components while the craft is in service.
Prior the art devices are designed to supply water to the drive unit in order that the marine engine can be test run when the craft is out of the water prior to taking the craft to the desired recreation area, but do not incorporate any method of monitoring whether correct initial water pressure is present or whether the water impeller is functioning correctly.
One embodiment of the present invention comprises a cylinder housing which has a female thread at one end to allow a standard garden hose to be attached to the cylinder. On the other end of the cylinder is a male thread which allows the cylinder to be attached to existing devices used in supplying pressurized water to the out drive unit. The invention also incorporates a nipple in its center to provide for the attachment of a calibrated gauge.
The gauge has two calibrated scales which are separated by a zero position between them. On one side of the zero position the gauge is calibrated to read water pressure in PSI, and on the other side of the zero position the gauge is calibrated to read Inches of Vacuum. The pressure side of the gauge measures the water pressure supplied to the drive unit from the garden hose or other source of input water. The gauge is scaled so the operator can adjust the inlet water pressure to a specific value and insure that a sufficient amount of water is being supplied so that the water impeller is not damaged when the marine engine is started. The gauge is rotatable to allow the scale to be rotated to the zero position prior to starting the engine. Upon starting the marine engine, the second scale of the gauge will communicate to the operator of the apparatus that the water impeller is providing adequate suction (Inches of Vacuum) to supply the engine with coolant water.
The gauge is calibrated in two modes to insure that the operator can visually determine by the calibrations on the gauge that sufficient water is initially being supplied and that the water impeller is providing sufficient suction to supply proper coolant to the engine when the craft is put in actual operation and the water impeller is not being supplied by a pressurized water source.
Additional forms of the present invention include the integration of the means to supply the pressurized water to the drive unit in conjunction with the impeller tester being an integral part of the water supplying device. Also, a form of the invention may be installed permanently in the watercraft and may display to the operator that the water impeller is providing an adequate water supply to the engine while the craft is in actual use.
It is an object of the instant invention to provide a new and useful impeller tester which has all the advantages of the prior art and none of the disadvantages.
It is another object of the instant invention to provide a new impeller tester which may be easily and efficiently manufactured and marketed.
It is a further object of the instant invention to provide a new impeller tester which is of a durable and reliable construction.
It is another object of the present invention to provide new and useful apparatus for testing the impeller of a marine drive unit.
It is another object of the present invention to provide new and useful apparatus for continually monitoring the output of an impeller in an marine drive unit.
It is another object of the present invention to provide an emergency water pump for a marine engine.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of the apparatus of the present invention.
FIG. 2 is a front view of the apparatus of FIG. 1.
FIG. 3 is a front view of the apparatus of FIG. 2 illustrating the use thereof.
FIG. 4 is a front view of the apparatus of the present invention sequentially following FIG. 3 and illustrating the operation thereof.
FIG. 5 is a front view of the apparatus of the present invention sequentially following FIG. 4 in illustrating the operation of the apparatus.
FIG. 6 is a view in partial section schematically illustrating an alternate embodiment of the apparatus of FIGS. 1-5.
FIG. 7 is a top view of the apparatus of FIG. 6.
FIG. 8 is a side view schematically illustrating an alternate embodiment of the apparatus of the present invention.
FIG. 9 is a perspective view illustrating the operation of the elements involved with the apparatus of FIGS. 1-7.
FIG. 10 is a view in partial section illustrating the operation of the apparatus of FIG. 7 related to the environment of a portion of the apparatus of FIGS. 8 and 9.
FIG. 11 is a schematic circuit diagram illustrating the operation of the apparatus of FIG. 8.
FIG. 12 is a schematic diagram of another alternate embodiment of the apparatus of the present invention.
FIG. 13 is a schematic representation of an alternate embodiment of the apparatus of the present invention utilizing an auxiliary electric water pump.
FIG. 14 is a schematic representation of an alternate embodiment of the apparatus of FIG. 13.
FIG. 15 is a schematic representation of another alternate embodiment of the apparatus of FIG. 13.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is an isometric projection of an impeller tester apparatus 10 in accordance with the present invention. The apparatus 10 includes a cylinder 1 through which water flows in the direction indicated by the arrows. A calibrated gauge 5 is secured to the cylinder 1 to indicate the relative pressure of the water flowing through the cylinder 1.
FIG. 2 is a front view of the calibrated gauge 5 included in the apparatus 10. The gauge 5 is set in a pre-test position and water is not being supplied to the crafts water impeller in the FIG. 2 condition.
FIG. 3 is a front view of the calibrated gauge 5, with water being supplied to the water impeller tester apparatus 10. The gauge 5 is indicating the water pressure supplied to the water impeller of a craft prior to starting the craft's engine.
FIG. 4 is a front pictorial view of the calibrated gauge 5 sequentially following FIG. 3, with the gauge 5 rotated clockwise to the zero position, effectively canceling out the pressure of the supplied water for test purposes.
FIG. 5 is a front pictorial view of the calibrated gauge 5, sequentially following FIG. 4. The craft's engine is now started and the calibrated gauge 5 is indicating that sufficient vacuum is being produced by the water impeller of the craft to insure that sufficient coolant is supplied to the engine of the craft when the craft is put in actual operation.
Arrows in FIGS. 1, 3, 4, and 5 indicate the direction of water flow.
The impeller tester apparatus 10 comprises the cylinder member 1, and at one end of the cylinder 1 there is an attachment 3 which allows the impeller tester 10 to be connected to a standard household water faucet or hose bib by a garden hose (See FIG. 7). At the opposite end of the cylinder 1 is a male threaded end 2 which attaches to an existing water supply device, such as shown in FIGS. 7 and 8, currently available for supplying coolant to the out drive of a boat.
Also attached to the cylinder member 1 is a nipple 4 which allows the calibrated gauge 5 to be attached to the cylinder member 1. The calibrated gauge 5 includes a zero position 6 between a positive pressure scale 7 and a vacuum pressure scale 8. Pressure is indicated by a pointer 9.
The calibrated gauge 5 incorporates the means for the operator to determine the necessary water pressure required for the water impeller by monitoring the reading of the pointer 9 on the positive pressure scale 7 when water is supplied but prior to starting the engine as shown in FIG. 3.
The calibrated gauge 5 is also capable of being rotated to the pre-test zero position 6. After the water impeller is supplied with an adequate water supply, as specified on the scale 7 within the calibrated gauge 5, the gauge is then rotated to the zero position 6, as shown in FIG. 4. At this time the marine engine is then started. The operator can then observe the vacuum scale 8 of the calibrated gauge 5 to determine if sufficient vacuum is being produced by the water impeller to supply the marine engine with proper coolant during its normal operation. This is determined by the operator observing the indication of the pointer 9 within vacuum scale 8, as shown in FIG. 5.
If the pointer 9 is within the appropriate range or scale value within the vacuum scale 8, then the required vacuum is present to insure that the water impeller is operating properly and will supply the marine engine with sufficient coolant to allow for safe operation when the craft in which the engine and the drive unit is disposed is put in its intended use environment.
FIG. 6 comprises a view in partial section schematically illustrating an alternate embodiment 100 of the apparatus 10 of FIGS. 1-5. FIG. 7 is a top view of the apparatus 100 of FIG. 6. For the following discussion, reference will primarily be made to FIGS. 6 and 7.
The embodiment 100 comprises a cylinder 102 with an input connector 104 on one end and a threaded, output connector 112 at the opposite end of the cylinder 102 from the input connector 104. Large arrows adjacent to FIGS. 6 and 7 illustrate the direction of the flow of the water through the apparatus 100.
Remote from the input connector 104, which is substantially identical to the attachment connector 3 of the apparatus 10 of FIGS. 1-5, and adjacent to the output connector 112, is a valve 106. The valve 106 is disposed in the bore of the cylinder 102. The valve 106 is a variable flow valve. The valve 106 includes a valve actuator 108 extending outwardly from the cylinder 102. Movement of the actuator 108 varies the flow of water through the valve 106 and accordingly through the cylinder 102.
Adjacent to the input connector 104 is an orifice 110. The orifice 110 extends through a wall at the input end 104 of the cylinder 102.
The purpose of the orifice 110 is to make certain that the apparatus 100 functions properly with low water pressure as input to the apparatus 100. The orifice 110 also serves to regulate the flow rate requirements for various size engine displacements.
Extending radially through the cylinder 102 is an air bleed aperture 114. The air bleed aperture 114 extends to an air bleed valve 116. The valve is shown in FIG. 7, while the aperture is shown in FIG. 6.
The purpose of the aperture 114 and the valve 116 is to allow air to be bled from the apparatus 100 when water is initially turned on. That is, when a hose is connected to the input connector 104, and water is turned on, the valve 116 is opened, and remains open until water flows substantially continuously from the valve 116. At that time air has been purged from the apparatus 100 and the valve 116 may then be closed.
Extending upwardly from the cylinder 102 is a nipple or conduit 117. The nipple or conduit 117 extends between the cylinder 102 and a gauge 118. The gauge 118 is substantially identical to the gauge 5 of the apparatus of FIGS. 1-5. The gauge 118 accordingly includes provision for zeroing the pointer after the initial water pressure stabilizes and before the engine to which the apparatus is connected begins to run. This is all as discussed above.
The purpose of the valve 106 and its actuator 108 is to enable an operator or user of the apparatus 100 to provide a desired initial pressure for the apparatus. In essence, the valve 106 and its actuator 108 work in conjunction with the orifice 110. It is preferable to have an initial desired pressure of 8 to 12 PSI from the input water connection 104 through the apparatus 100 and on to the tester apparatus, as will be discussed in detail below.
It appears that a minimum pressure of about 6 PSI is required in order to accurately test an impeller of a boat drive system. Thus, when the air bleed valve 116 is closed, the valve actuator 108 is adjusted to control the flow through the cylinder 102 in order to provide the desired initial pressure of about 8 to 12 PSI. A maximum desired pressure is about 14 PSI. When the initial pressure has been set, the indicator or pointer is then zeroed, as illustrated in FIG. 4, in order to test the impeller of the boat drive, as will be discussed in detail below.
If desired, the absolute pressure scale of the gauge 118, which shows only the pressure of the water, before the zeroing function, may be appropriately color coded. Accordingly, there would be a yellow line between 6 and 8 PSI on the scale, then a green line between 8 and 12 PSI, and another yellow line between 12 and 14 PSI. A red line would extend above 14 PSI to indicate that such pressure is too high for proper functioning of the tester apparatus.
FIG. 8 is a schematic diagram illustrating an alternate embodiment of the apparatus of the present invention. The embodiment of FIG. 8 includes a drive unit 20 which is connected to a water cooled engine 50. FIG. 10 comprises a view in partial section through the drive unit, and a tester is shown secured to the drive unit. For the following discussion, reference will primarily be made to FIGS. 8 and 10.
The drive unit 20 includes a housing 22 with a pair of water input openings 24 and 25 in the housing 22. A pair of conduits 26 and 27 extend from the openings 24 and 25, respectively, to a housing or chamber 29 in which is disposed an impeller 28. From the chamber 29 in which the impeller 28 is disposed, a conduit 30 extends through the drive 20 and to a tee 32.
When the drive unit 20 is disposed in the water, the chamber 29 is below the water line so that the chamber automatically fills with water. The water line is indicated in FIG. 8 by a dashed line 21.
From the tee 32, a conduit 34 extends to a water pump 52 on the engine 50. The water pump 52 receives the flow of water from the impeller 28 and circulates the water as a coolant through the engine 50.
From the engine 50, a return water conduit 54 extends to the drive unit 20 and to a conduit 36 therein. The water from the conduits 54 and 36 is then discharged from the drive 20 adjacent to a propeller 38.
The mechanical elements which transmit the power from the engine 50 to the propeller 38 are not shown, since they are not part of the present invention. Rather, only the engine 50 and its components which relate rather directly to the present invention, along with the drive unit 20 and its elements, which are cooperatively involved in the present invention, are illustrated.
From the tee 32, a conduit 60 extends to a gauge 62. The gauge 62 is responsive to the pressure of the water flowing in the conduit 30 from the impeller 28.
With the engine 50 operatively connected to the drive 20, and with the drive 20 disposed in water, the output of the impeller 28 to the water pump 52 is monitored by the gauge 62. The gauge 62 is a pressure gauge which has a direct reading, unlike the gauge 5 illustrated in FIGS. 1-5. Thus, the gauge 62 monitors the output of the impeller 28 to provide cooling water to the water pump 52 while the drive 20 is in the water, and while the drive 20 is propelling a craft powered by the engine 50.
Another alternate embodiment of the apparatus of the present invention is illustrated in FIGS. 9 and 10. FIG. 9 comprises a perspective view of the apparatus of FIGS. 1-7 in a use environment for monitoring the output of the impeller 28 when the drive 20 is out of the water. A hose 13, which may be a garden hose, or the like, appropriately connected to a source of water pressure, is connected to the attachment 3 of the cylinder 1. The opposite end of the cylinder 1, remote from the input attachment 3, is in turn connected to a testing clamp or tester 70.
FIG. 10 comprises a view in partial section through the testing clamp 70 disposed over the openings 24 and 25 in the drive housing 22. For the following discussion, reference will primarily be made to FIGS. 9 and 10.
The tester 70 includes a pair of cups, including a cup 72 and a cup 82. The cups 72 and 82 are secured together by a clamp 92. The cup 72 includes a knob 74, and one portion of the clamp 92 is secured to the knob 74. The cup 72 is secured to the drive housing 22 over the opening 25.
The cup 82 includes a knob 84, and a bore 86 extends through the knob 84 and the cup 82 to communicate with the interior of the cup 82 and accordingly to communicate with the opening 24 when the tester 70 is in place. The clamp 92 is also secured to the knob 84 of the cup 82.
A conduit 88, with a fitting 90, is appropriately secured to the cup 82 at the bore 86.
A flow of water through the hose 13 flows through the cylinder 1, which is secured to the fitting 90, and through the conduit 88, the opening 24, the conduit 26, and to the impeller 28 in the chamber 27. The gauge 5 is adjusted as discussed above in conjunction with the explanation of FIGS. 1-5, to indicate the pressure of the flow of water through the hose 13. When the engine 50 is then started, if the impeller 28 is functioning properly, there will be a drop in the pressure, as indicated in FIG. 5. The drop in pressure indicates the functioning of the impeller 28.
FIG. 11 is a schematic circuit diagram of another alternate embodiment of the apparatus of the present invention, and related primarily to the embodiment of FIG. 8.
In the embodiment of FIG. 11, a light or lamp system embodiment 120 is illustrated. The light or lamp system embodiment 120 includes an input water conduit 122, which is comparable to the conduit 30 illustrated in FIG. 8. The conduit 122 extends to a pressure transducer 124, which replaces the tee 32 of FIG. 8. A conduit 126 extends from the pressure transducer 124 to a water pump, such as the water pump 52 of FIG. 8.
The pressure transducer 124 is connected to a battery 130 by a conductor 132. The pressure transducer 124 is also connected to a lamp 136 by a conductor 134.
During the operation of the engine to which the apparatus 120 is connected, if the pressure sensed by the pressure transducer 124 drops below a predetermined minimum, current flows from the battery 130 through the conductors 132, the transducer 124, and the conductor 134 to illuminate the lamp 136. The illumination of the lamp 136 indicates that there is a drop in the water pressure. This in turn indicates that the impeller which provides a flow of water through the conduit 122 is not functioning properly.
FIG. 12 comprises a schematic circuit diagram of an alternate embodiment of the light system embodiment of FIG. 11. FIG. 12 accordingly comprises an enhanced electronic or lamp system 150 in which the output of a pressure transducer 152 is modified or varied in accordance with the speed of an engine, not shown, such as the engine 50.
In the embodiment of FIG. 12, the water input conduit 122 from the embodiment of FIG. 8 is again illustrated as comprising the water input to the pressure transducer 152. The water conduit 126 then extends from the pressure transducer 152 to the water pump of the engine to which the apparatus 150 is connected, as discussed above.
The output of the pressure transducer 152 varies in response to the pressure of the water in conduit 122, and the water pressure in turn is responsive to the speed of the engine, such as the engine 50, to which the apparatus 150 is connected.
The speed of the engine is transmitted from an engine coil or ignition module 154 on a conductor 156 to an electronic control module 160. The electronic control module 160 includes microprocessor technology to respond to the speed of the engine, as indicated by input pulses on the connector 156 from the coil or module 154, and to predetermined parameters of pressure, depending on engine speed. Power for the control module 160 is provided by the conductor 132 from a battery, such as the battery 130 as shown in FIG. 11.
A conductor 162 extends from the control module 160 to the transducer 152. Input voltage to the transducer 152 flows to the transducer 152 on the conductor 162, and an output voltage from the transducer 152 is transmitted to the control module 160 on a conductor 164. The voltage on conductor 162 comprises control voltage for the transducer 152, and is battery voltage. The output voltage from the transducer 152 on conductor 164 comprises input voltage for the control module 160.
The electronic control module 160 interprets the input voltage on conductor 164 from the transducer 152 in terms of the rpm of the engine, as indicated by the input pulses or input signal on conductor 156. It is only when the two input signals on conductors 156 and 164 are "out of balance" that an output from the control module 160 on a conductor 166 to the lamp 136 causes the lamp 136 to be illuminated. Thus, the illumination of the lamp 136 indicates an imbalance in the desired or appropriate pressure in the conduit 122 in relation to the rpm of the engine.
There has thus been outlined, rather broadly, the more important features of the instant invention in order that the detailed description may be better understood, and in order that the present contribution to the art may be better appreciated. Those skilled in the art will appreciated 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 instant invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the instant invention.
The gauges discussed above in conjunction with the various embodiments have been generally described simply as "gauges" without regard to their types. Reference has been made to absolute pressure, and, of course, reference has been made to the zeroing of the gauge and the illustration of vacuum pressure on one side of the zero and positive pressure on the other side of the scale. This is best shown in FIGS. 1-5. The pressure gauges accordingly have been direct reading pressure gauges, in which the pressure is a direct reading resulting from the flow of the water through the cylinders to which the gauges are attached. However, it may be desired to use a liquid filled gauge, which includes a diaphragm for actuating a pressure pointer. In such case, a movable bezel will be fitted over the liquid filled gauge, with the movable bezel simply showing a zero index which will be placed over the pointer after the initial pressure has been established. When the engine of the boat is started after the gauge has been zeroed, a pressure drop may be noted from the zero point.
Moreover, while the apparatus of the present invention has been described in terms of a drive unit 20, shown as a stern drive unit connected to an inboard engine 50, it is obvious that the invention also applies to a total outboard unit in which the engine is disposed above the drive unit. Such is illustrated in dash dot line in FIG. 8 by an engine 51 disposed at the upper portion of the drive unit 20. Such are well known as simply outboard units. Such outboard units have essentially the same elements and requirements as discussed in conjunction with the engine 50.
FIG. 13 comprises an alternate embodiment of the apparatus of the present invention in which an auxiliary or emergency water pump is used in the environment of FIG. 12.
FIG. 13 shows a transom 180 of a boat or water craft, but with the drive unit omitted for purposes of clarity. The water line 21 is indicated by the dashed line. Beneath the water line 21, and extending through the transom 180, is an aperture 182. A conduit 184 extends from the aperture 182 to a pump 186. A conduit 188 extends from the pump 186 to a one way check valve 190. A conduit 192 extends from the one way check valve 190 to a tee element 194.
The input conduit 122 from the impeller (See FIG. 12) is shown extending to the transducer 152, and the conduit 126 is shown extending from the transducer 152 to a check valve 127. From the check valve 127, a conduit 140 extends to the tee 194. Thus, water flow from both the impeller through the conduit 122, etc. and from the pump 186 extends to the tee 194. From the tee 194, a conduit 196 then extends to the engine driven water pump, such as the pump 52. Shown in FIG. 8.
Output of the pump 186, which is an electrical pump, is controlled by the control module 160. The control module 60 acts in substantially the same way as discussed above in conjunction with FIG. 12. Thus, when the control module 60 senses that the output of the impeller through the conduit 122 and the transducer 152 is below a predetermined minimum, current transmitted on conductor 166 will cause the lamp 136 to be illuminated, thus advising the users of the craft that the impeller of the drive unit has either failed or is not producing substantial water output for cooling the engine.
A conductor 168 extends from the conductor 166 to the emergency or auxiliary pump 186. The current flow on the conductor 166 and the conductor 168 will cause the pump 186 to begin pumping cooling water from below the water line 21 through the aperture 182 and the conduit 184, etc., as discussed above. The pump 166 is illustrated as a constant speed pump, and its output is accordingly constant.
It will be understood that the auxiliary pump 186 may also be used in the environment of FIG. 11, in which the engine RPM is not taken into consideration with respect to the pumping efficiency of the impeller of the drive unit. Rather, in the embodiment of FIG. 11, if the flow of water from the impeller through the conduit 122 drops below a predetermined minimum, as sensed by the transducer 124, current flows through the conductor 134 to illuminate the warning lamp 136. In such case, the pump 186 may be connected directly to the conductor 134, again causing the pump 186 to pump water to the engine driven water pump.
The check valves 190 and 127 insure that there is a one way flow of the water to the engine driven water pump.
FIG. 14 comprises a schematic representation of an alternate embodiment of the apparatus illustrated schematically in FIG. 13, utilizing a solenoid to actuate the auxiliary pump 186. Essentially, the above description of the apparatus illustrated in FIG. 13 is also applicable to the embodiment of FIG. 14, except that a solenoid 200 is connected to the conductor 166 by a conductor 202. In turn, the solenoid 200 is connected to the pump 186 by a conductor 204. A conductor 206 extends from the conductor 204 to a lamp 208.
When the information from the transducer 152 indicates that water flowing through the conduit 122 from the impeller in the drive unit drops below a predetermined minimum flow rate in accordance with the parameters determined in response to the speed of the engine from the coil or the ignition module 154, the control module 160 causes a current flow in conductor 166 to illuminate the warning lamp 136. At the same time, the current flow in conductor 166 is transmitted by the conductor 202 to the solenoid 200. The solenoid 200 is thus energized, and in turn turns on the pump 186. The pump 186 is a variable speed pump whose output varies with its input voltage. The input voltage to the pump 186 is from the control module 160 on conductor 170 through the now energized solenoid 200 and the conductor 204 from the solenoid. Current on conductor 204 also illuminates the lamp 208 via conductor 206. The lamp 208 confirms that the solenoid 200 has been energized to turn on the pump 186.
The voltage on conductor 170 is a variable voltage, responding to the input from the distributor 154. The output of the pump 186 thus varies with engine speed.
The pump 186 pumps water from the aperture 182 and the transom 180 beneath the water line 21 through the conduit 184, and through the conduit 188 and through the one way check valve 190, and the conduit 192 to the tee 194. The water from the pump 186 then flows through the conduit 196 to the engine driven water pump (See FIG. 8). The check valve 127 insures that water from the conduit 192 does not flow backwards, but flows only through the conduit 196 to the engine driven water pump.
FIG. 15 comprises another alternate embodiment in which the impeller of the drive unit is completely eliminated. The electric pump 186 is connected directly to the transducer 152 by the conduit 188. Thus, water from below the water line 21 flows through the aperture 182 in the transom 180 and through the conduit 184 directly to the pump 186. From the pump 186, the conduit 188 extends to the transducer 152. From the transducer 152, the conduit 126 extends to the engine of the water craft and to the engine driven water pump thereon.
RPM information from the engine (See FIG. 8) is sensed by the distributor coil 154 and is transmitted on conductor 156 to the control module 160. An appropriate voltage is transmitted to the pump 186 on conductor 165 from the control module 160. The voltage on conductor 165 varies with the speed of the engine as represented by the output from the distributor 154.
Thus, the pump 186 of FIG. 13 is a constant speed pump, while the pumps, 186 of FIGS. 14 and 15 are variable speed pumps providing outputs in response to engine speed. Thus, the output of the pump 186 is directly related to the engine RPM or engine speed information sensed by the distributor 154 and transmitted to the control module 160.
From the control module 160, information is transmitted on conductor 162 to the transducer 152. In turn, output information from the transducer 152 is transmitted to the control module 160 on conductor 164 to confirm that the pump 186 is working properly.
The warning lamp 136 is illuminated by an output on the conductor 166 from the control module 160 if the output of the pump 186 fails or is below the predetermined minimum, as determined by the control module 160.
The control module 160 is in turn controlled by an ignition switch 133 in the conductor 132 from the battery positive. Thus, the pump 186 will only operate when the ignition switch 133 of the craft in which the apparatus is installed is closed, thus indicating that the engine is "on" and operating.
While the principles of the invention have been made clear in illustrative embodiments, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, the elements, materials, and components used in the practice of the invention, and otherwise, which are particularly adapted to specific environments and operative requirements without departing from those principles. The appended claims are intended to cover and embrace any and all such modifications, within the limits only of the true spirit and scope of the invention.
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A marine engine is provided with a drive unit which incorporates a water impeller to supply water to the marine engine in order to maintain proper engine cooling. Devices are currently available that allow the watercraft's engine to be started when the craft is not in actual service. These devices attach to the crafts out drive unit and they provide for water, from a household faucet, to be supplied to the water impeller. These devices have no form of measurement to communicate to the operator that a sufficient amount of water is initially being supplied to the water impeller to prevent damage to that component nor do they communicate if the water impeller is capable of producing sufficient suction to feed the crafts engine with sufficient coolant so that the engine will not over-heat when the craft is placed in its operating environment. The present invention includes an impeller tester which may be placed in existing drive water supply devices or which may be permanently installed in the water craft. The apparatus communicates to the operator of the craft that a sufficient supply of water is available and that the water impeller will not be damaged upon starting and running the craft's engine.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a backpack assembly with audio components and more particularly pertains to generating sound through components in a backpack.
2. Description of the Prior Art
The use of backpacks and radios is known in the prior art. More specifically, backpacks and radios heretofore devised and utilized for the purpose of generating sound from radios in various devices are known to consist basically of familiar, expected, and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which has been developed for the fulfillment of countless objectives and requirements.
By way of example, the prior art discloses in U.S. Pat. No. 4,084,139 to Jakobe a shoulder supported stereophonic radio receiver.
U.S. Pat. No. 4,484,276 to Sata discloses a personal audio device.
U.S. Pat. No. 4,589,134 to Waldron discloses a personal sound system.
U.S. Pat. No. 4,764,962 to Eckman discloses a stereo speaker system for walkman-type radio and/or cassette player.
U.S. Pat. No. 4,785,984 to Seitz-Gangemi discloses an athletic radio holder.
In this respect, the backpack assembly with audio components according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of generating sound through components in a backpack.
Therefore, it can be appreciated that there exists a continuing need for new and improved backpack assemblies with audio components which can be used for generating sound through components in a backpack. In this regard, the present invention substantially fulfills this need.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of backpacks and radios now present in the prior art, the present invention provides an improved backpack assembly with audio components. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved backpack assembly with audio components and method which has all the advantages of the prior art and none of the disadvantages.
To attain this, the present invention essentially comprises a new and improved backpack assembly with audio components comprising, in combination, a backpack having a container for the support of materials to be transported, the backpack having a lower face, an upper face, a front face, a rear face and side faces as well as shoulder straps for receipt by a user; a plurality of pockets formed in one of the side faces, the pockets including a first upper pocket having an aperture with a speaker secured therein, the aperture having a screen on its exterior surface for covering the speaker, a supplemental support sheet interior of the first pocket with an aperture adjacent to the lower end for the passage of a speaker wire, the upper end of the upper pocket being opened with an internal flap secured thereabove to the interior of the side wall and a downwardly extending edge removably couplable with the upper edge of the first pocket; a second lower pocket formed in the side wall beneath the first pocket, the second pocket having a height of about two times its width, the second pocket having an interior support sheet secured at its lower end to the backpack beneath the second pocket and having an upper opened end with an internal flap secured at its upper edge to the interior of the side wall above the second pocket and having a lower edge releasably secured to the upper edge of the second pocket, the second pocket having an exterior opening with a laterally disposed cross-piece therebetween with a first external flap secured at its upper end to the exterior surface of the backpack above the second pocket for exposing the battery region of a radio in the second pocket and a lower end releasably secured to the crosspiece and a second external flap secured to the cross piece and a lower end releasably secured to the exterior of the backpack beneath the second opening for providing access to the radio controls; and a radio located within the second pocket.
There has 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.
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 its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions 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. 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.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent of 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.
It is therefore an object of the present invention to provide new and improved backpack assemblies with audio components which have all the advantages of the prior art backpacks and radios and none of the disadvantages.
It is another object of the present invention to provide new and improved backpack assemblies with audio components which may be easily and efficiently manufactured and marketed.
It is further object of the present invention to provide new and improved backpack assemblies with audio components which are of durable and reliable constructions.
An even further object of the present invention is to provide new and improved backpack assemblies with audio components which are susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly are then susceptible of low prices of sale to the consuming public, thereby making such backpack assembly with audio components economically available to the buying public.
Still yet another object of the present invention is to provide a new and improved backpack assemblies with audio components which provide in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
Still another object of the present invention is to generate sound through components in a backpack.
Lastly, it is an object of the present invention to provide new and improved backpack assembly with audio components comprising a backpack having a container for the support of materials to be transported, the backpack having a lower face, an upper face, a front face, a rear face and side faces; a plurality of pockets formed in one of the side faces, the pockets including a first upper pocket having an aperture with a speaker secured therein, a supplemental support sheet interior of the first pocket with an aperture adjacent to the lower end for the passage of a speaker wire, the upper end of the upper pocket being opened with an internal flap secured thereabove to the interior of the side wall and a downwardly extending edge removably couplable with the upper edge of the first pocket; and a second lower pocket formed in the side wall beneath the first pocket, the second pocket having an interior support sheet secured at its lower end to the backpack beneath the second pocket and having an upper opened end with an internal flap secured at its upper edge to the interior of the side wall above the second pocket and having a lower edge releasably secured to the upper edge of the second pocket, the second pocket having an exterior opening with a laterally disposed cross-piece therebetween with a first external flap secured at its upper end to the exterior surface of the backpack above the second pocket for exposing the battery region of a radio in the second pocket and a lower end releasably secured to the crosspiece and a second external flap secured to the cross piece and a lower end releasably secured to the exterior of the backpack beneath the second opening.
These together with other objects of the invention, along with 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 the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
FIG. 1 is a perspective view of the preferred embodiment of the new and improved backpack assembly with audio components constructed in accordance with the principles of the present invention.
FIG. 2 is a perspective view of one side of the backpack of FIG. 1 with the flaps lifted.
FIG. 3 is a cross-sectional view of the upper portion of the sound components of FIG. 2.
FIG. 4 is a cross-sectional view of the lower portion of the sound components of FIG. 2.
FIG. 5 is a perspective view of the improved backpack assembly illustrated in FIG. 1 showing the internal compartments of the backpack.
FIG. 6 is a perspective view of a shoulder strap of the backpack assembly.
The same reference numerals refer to the same parts through the various Figures.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference now to the drawings, and in particular to FIG. 1 thereof, the preferred embodiment of the new and improved backpack assembly with audio components embodying the principles and concepts of the present invention and generally designated by the reference numeral 10 will be described.
The present invention, the new and improved backpack assembly with audio components, is comprised of a plurality of component elements. Such elements in their broadest context include a backpack, pockets including an upper pocket and a lower pocket and a radio within the lower pocket. Such components are specifically configured and correlated with respect to each other so as to attain the desired objective.
More specifically, the backpack assembly 10 has as its main component a backpack 12. Such backpack is a container for support of materials to be transported. The backpack includes a lower face 14, an upper face 16, a front face 18, a rear face 20 and side faces 22. The backpack also includes shoulder straps 24 for receipt by the arms of a user.
Within the backpack is a plurality of pockets. Such pockets are formed on one side face 28. Such pockets include a first upper pocket 30. Such upper pocket has an aperture 32. An audio speaker 34 is secured within the aperture. The aperture is also provided with a screen on its exterior surface for covering the speaker.
Within the first pocket is a supplemental support sheet 38. Such support sheet is interior of the first pocket. It has an aperture 40 adjacent to the lower end for the passage of a speaker wire 42. The upper end 44 of the upper pocket is formed with an opening 46. It also includes an internal flap 48 secured thereabove to the interior of the side wall. It also has a downwardly extending edge 50. Such edge is removably couplable with the upper edge 52 of the first pocket.
Next provided is a second or lower pocket 56. The second pocket is formed in the side wall beneath the first pocket. The second pocket has a height of about two times its width.
The second pocket has an interior support sheet 60. Such sheet is secured at its lower end 62 to the backpack beneath the second pocket. The support sheet also has an upper opening 64 with an internal flap 66 secured at its upper edge 68 to the interior of the side wall. Such securement is above the second pocket. The internal flap also has a lower edge 70 which is releasably secured to the upper edge 72 of the second pocket.
The second pocket has an exterior opening 76 with a laterally disposed crosspiece 78 therebetween. It also has a first external flap 80 secured at its upper end 82 to the exterior surface of the backpack above the second pocket. This functions for exposing the battery region 84 of the radio 86 located in the second pocket. The first external flap also has a lower end 88 secured to the crosspiece and a second external flap 90 secured to the crosspiece and a lower end 92 releasably secured to the exterior of the backpack beneath a second opening. This arrangement is for providing access to the radio controls 94.
The last component of the system is the radio located within the second pocket for providing the music to be played through the speaker, support being totally provided by the backpack at one side edge.
The present invention is an adaptation of products that already exist on the market. The present invention comprises a backpack which is used by students during the school year and campers which is used year round.
The products that adapt to the backpack may include a radio, cassette-player or compact disc. These articles are well-known and have different presentations according to quality, power, functions etc. When combining the backpack with its different presentations, the result is a new product that has a great market.
The present invention is a product consisting of a backpack that has a radio installed in the lower part of its right side and one speaker in each side on the upper part. The radio is installed through the inside of the backpack but all covered by a rubber cover, in such a way that when putting in--or taking out books or other things, the radio is not seen, touched or moved. On the outside, there are only three buttons (on/off volume, tuning and balance), the dial, and a plug for the headphones. These buttons are easily reached by reaching back when wearing the backpack. All this is covered by a flap that has a square of Velcro on its inner lower part, on the upper part of the flap, there will be a zipper which when opened, will show a hard plastic box that contains the batteries.
The speakers will have a two inch diameter which will be inserted through the inside of the backpack and covered with plastic so they will not be seen or moved. From the outside, the speakers will be seen as hard plastic circles with perforations. The connecting wires of the radio to the speakers will go inside and covered with plastic so they will not be seen.
This model can be made with low quality materials for the backpack and an AM radio so it can be sold for a low price. It can also be presented with high quality materials for the backpack and an AM/FM radio and be sold for a higher price in stores where higher quality products are sold.
This model has basically the same installation than the model with the radio, with the difference that what is being installed here is a cassette player. The flap on the side will cover the small door where the cassette goes, the keys and control knobs.
A great variety of products can be presented in this model, for example, backpack with cassette player, backpack with cassette player with an AM/FM radio, tape recorder and player with AM/FM radio, etc. They can also have different types of controls like an equalizer, sound balance on the speakers, tuning control, etc.
In some models the speakers can be rectangular and instead of going on the sides of the backpack, they will go on the two straps, so that when wearing the backpack, the speakers will end up close to the shoulders from the front.
In the model with a compact disc player, the compact disc player will be installed in the backpack for the higher price market.
In the model with the sound pack for the beach, a cassette player with an AM/FM radio or a compact disc can be installed. the material of this backpack will be of a neon-colored plastic of several different sizes, the purpose being for putting towels, combs, swimsuits, etc. in it. The side walls will be rigid to hold the sound system, but it may be given another position due to that in this model an additional protection is needed so that sand or water will not get in the cassette player or compact disc player.
As to the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided.
With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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A backpack assembly for holding audio components comprising a backpack having lower, upper, front, rear and two side faces. One of the side faces includes a plurality of pockets formed interiorly of the bag. One of the plurality of the pockets is sized to hold a speaker therein and a second of the plurality of pockets is sized to hold a radio therein wherein the radio and the speaker are operatively connected by a speaker wire extending from the speaker to the radio.
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The invention described herein was made in the course of work under a grant or award from the Department of Health, Education, and Welfare.
DESCRIPTION
1. Technical Field
This invention relates to a compound which is characterized by vitamin D-like activity.
More specifically this invention relates to a derivative of vitamin D 3 .
Vitamin D 3 is a well-known agent for the control of calcium and phosphorous homeostasis. In the normal animal or human this compound is known to stimulate intestinal calcium transport and bone-calcium mobilization and is effective in preventing rickets.
It is also now well known that to be effective vitamin D 3 must be converted in vivo to its hydroxylated forms. For example, the vitamin is first hydroxylated in the liver to form 25-hydroxy vitamin D 3 and is further hydroxylated in the kidney to produce 1α,25-dihydroxy vitamin D 3 or 24,25-dihydroxy vitamin D 3 . The 1α-hydroxylated form of the vitamin is generally considered to be the physiologically active or hormonal form of the vitamin and to be responsible for what are termed the vitamin D-like activities, such as increasing intestinal absorption of calcium and phosphate, mobilizing bone mineral, and retaining calcium in the kidneys.
2. Background Art
References to various of vitamin D derivatives are extant in the patent and other literature. See, for example, U.S. Pat. Nos. 3,565,924 directed to 25-hydroxycholecalciferol; 3,697,559 directed to 1,25-dihydroxy cholecalciferol; 3,741,996 directed to 1α-hydroxycholecalciferol; 3,907,843 directed to 1α-hydroxyergocalciferol; 3,715,374 directed to 24,25-dihydroxycholecalciferol; 3,739,001 directed to 25,26-dihydroxycholecalciferol; 3,786,062 directed to 22-dehydro-25 -hydroxycholecalciferol; 3,847,955 directed to 1,24,25-trihydroxycholecalciferol; 3,906,014 directed to 3-deoxy-1α-hydroxycholecalciferol; 4,069,321 directed to the preparation of various side chain flourinated vitamin D 3 derivatives and side chain fluorinated dihydrotachysterol 3 analogs.
DISCLOSURE OF INVENTION
A new derivative of vitamin D 3 has now been found which expresses excellent vitamin D-like activity and which, therefore, could serve as a substitute for vitamin D 3 in its various known applications and would be useful in the treatment of various diseases such as osteomalacia, osteodystrophy and hypoparathyroidism.
This derivative has been identified as 24,24-difluoro-25-hydroxycholecalciferol (24,24-difluoro-25-hydroxy vitamin D 3 or 24 F 2 ,25-OHD 3 ).
BEST MODE FOR CARRYING OUT THE INVENTION
The compound of this invention was synthesized in accordance with the following description and abbreviated schematic: ##STR1##
Cholenic acid 1 was treated with dihydropyran in a suitable organic solvent (CH 2 Cl 2 ) at 0° in the presence of P-toluene sulfonic acid and then with 1 N Na OH in ethanol at 20° to form the cholenic acid tetrahydropyranyl ether (protection of the hydroxyl group in the A ring). This compound was then treated with an excess of CH 3 Li in tetrahydrofuran (THF)-ethyl ether at 0° C. for four hours after which the protective tetrahydropyranyl group was removed by treatment with ρ-TsOH in CH 2 Cl 2 -methanol for 24 hours at 20° C. Subsequent acetylation (Ac 2 O-pyridine-CH 2 ,20°, 24 hours) gave the methylketone 2 (mp 148°-151°, δ2.12 (3H,s,C-25), m/e 354 (M-60)) (Yield=6% overall from 1).
The methylketone 2 was refluxed for seven hours in acetic anhydride in the presence of ρ-TsOH (enolacetylation) to give the diacetate 3 (mp 109°-110°, δ5.02 (1H, m, C-23) 1.90 (3H,s,C-25) m/e 396 (M-60)). The diacetate was then converted to the difluorocyclopropane 4 by heating with sodium chlorodifluoro-acetate in diglyme at 170° for 0.5 hours. Yield, 34%; mp 112°-115°, 5.38 (1H,m,C-6), 4.60 (1H,m,C-3), 2.05 (3H,s,24-OAc), 2.02 (3H,s, 3-OAc), 1.60 (3H,m,C-26), m/e 446 (M-60)).
Treatment of 4 with LiOH in THF-methanol-water at 20° C. for two hours followed by acetylation (AC 2 O-pyridine-CH 2 Cl 2 ,20°, 24 hr.) gave, after chromatography on silica gel, the difluoroketone 5(9.3% yield, mp 135°-136-5°, δ2.26 (3H,t,J HF =1 Hz,C-26), m/e 404 (M-60)). The difluoroketone was obtained in a mixture with the 23(E)-and the 23(Z)-conjugated ketone, with the difluoroketone being separated by chromatography on silica gel).
The difluoroketone 5 was reacted with an excess of CH 3 Mg1 in ethyl ether at 0° C. for 15 minutes and was then acetaylated (AC 2 O-pyridine-CH 2 Cl 2 , 20°, 20 hr.) to furnish the 25-carbinol, 6, in 85% yield (mp 163°-164-5°, δ1.28 (6H,s,C-26,27), m/e 420 (M-60)). The carbinol, 6, was allylically brominated by reacting it with N-bromo-succinimide in refluxing CCl 4 for 25 minutes. The brominated compound was then dehydrobrominated by treatment with s-collidine in refluxing xylene for 15 minutes to give a mixture of the 4,6-diene and the 5,7-diene, 7. The 5,7-diene (λmax 263, 272, 282 and 292 nm, m/e 419 (M-59)) was isolated in 28% yield, by treatment with ρTsOH in acetone at 20° for 15 hours followed by preparative thin-layer chromatography (benzene-ethyl acetate (15:1), 3times). The recovered 5,7-diene was saponified by treatment with 5% KOH-methanol at 20° C. for 15 hours and then irradiated (Hanovia high pressure quartz mercury vapor lamp, model 654A36; 200 W) in a mixture of ethanol and benzene for 2.5 minutes at b 0° C. to give the previtamin 8 in solution. The irradiated solution was refluxed for one hour and then fractionated with thin-layer chromatography (silicagel, benzene-ethyl acetate, (5.1), 3 times) and high pressure liquid chromatography (Zorbax SIL, 25 cm×2.1 mm i.d., available through the DuPont Co., Wilmington, Delaware) CH 2 Cl 2 ) to yield 24,24-difluoro-25-hydroxy vitamin D 3 , 9, (λmax 264 nm, λmin 228 nm, m/e 436 (M+), 421, 418, 403, 377, 271, 253, 136, 118).
Statement
If it is desired for certain purposes the acetylated 5,7-diene after recovery as described above can be saponified by well known means (5% KOH in MeOH, 20°, 15 hours) to convert the acetoxy group at the 3-position to hydroxyl.
Also, if desired, the previtamin 8 can be recovered by evaporation of solvent at 5° and the subsequent chromatograph on silica gel, and subsequently converted to the vitamin.
Biological Activity
Male weanling rats were housed in hanging wire cages and fed ad libitum the low calcium, vitamin D deficient diet described by Suda et al (J. Nutr. 100, 1049 (1970)) for three weeks prior to their use in the following assays.
Intestinal Calcium Transport
Groups of five or six rats fed as above were given respectively a single dose (650 ρmole) of either 24,24-difluoro-25-hydroxy vitamin D 3 (24 F 2 ,25-OH 2 ) or 25-hydroxy vitamin D 3 (25-OHD 3 ) dissolved in 0.05 ml of 95% ethanol intrajugularly 8, 23 or 30 hours prior to sacrifice. The rats in the control group were given the ethanol vehicle only. They were then killed by decapitation after the respective times prescribed and their duodena were used to measure the intestinal calcium transport activity in accordance with the techniques of Martin and DeLuca (Am. J. Physiology 216, 1351 (1969)). Results are shown in the table below.
Table 1______________________________________ Compound .sup.45 Ca serosal/.sup.45 Ca mucosalGiven 8 h 23 h 30 h______________________________________Control 2.7 ± 0.2*.sup.(a) 2.5 + 0.4.sup.(a) 2.6 ± 0.2.sup.(a)24F.sub.2,25- 6.6 ± 1.2.sup.(b) 5.9 ± 0.6.sup.(b) 8.2 ± 2.1.sup.(b)OHD.sub.325-OHD.sub.3 5.0 ± 0.7.sup.(c) 5.5 ± 0.8.sup.(c) 5.7 ± 1.4.sup.(c)Significance (b) & (c) from (b) & (c) from (b) & (c) fromof difference (a) (a) (a) ρ<0.001 ρ<0.001 ρ<0.001 (b) from (c) (b) from (c) (b) from (c) ρ<0.025 N.S. ρ<0.05______________________________________ *Standard deviation of the mean
To show the effect of small doses of 24F 2 ,25-OHD 3 on intestinal calcium transport rats fed the low calcium diet as indicated above, in groups of 5 or 6 were given a single dose of 24F 2 ,25-OHD 3 or 25-OHD 3 dissolved in 0.05 ml of 95% ethanol intrajugularly. Rats in the control group received the vehicle alone. Either 20 hours or 168 hours after receiving the dose the rats were killed and their duodena were used to measure the intestinal calcium transport activity in accordance with the Martin and DeLuca procedure referenced above. Results are shown in Table 2 below.
Table 2______________________________________Compound Dosage .sup.45 Ca serosal/.sup.45 Ca mucosalGiven (ρmole/rat 20 h 168 hControl 1.5 ± 0.5*.sup.(a) 2.0 ± 0.4.sup.(a)24F.sub.2, 25-OHD.sub.3 6.5 1.9 ± 0.6.sup.(b) 2.1 ± 0.1.sup.(b) 32.5 1.9 ± 0.3.sup.(b) 3.7 ± 0.9.sup.(c)25-OHD.sub.3 6.5 1.8 ± 0.4.sup.(b) 2.1 ± 0.2.sup.(b) 32.5 2.2 ± 0.6.sup.(b) 3.8 ± 0.7.sup.(d)Significance (b) from (a) (b) from (a)of difference N.S. N.S. (c) from (a) ρ<0.05 (d) from (a) ρ<0.001______________________________________ *Standard derivative of the mean
Serum Calcium Concentration
Rats fed as indicated above were divided into groups of six rats each. The rats in one group were given a single dose of 650 ρ mole of 24F 2 ,25-ODH 3 , in the second group a dose of 650 ρ mole of 25-OHD 3 (in each case the vitamin D 3 derivative was dissolved in 0.05 ml of 95% ethanol) while the third group (control) was given the vehicle alone. The materials were administered intrajugularly either 8 or 29 hours prior to sacrifice.
The rats were killed by decapitation after the indicated times, the blood collected and centrifuged to obtain the serum. The serum (0.1 ml) was mixed with 1.9 ml of 0.1% NaCC solution and the calcium concentration was measured with an atomic absorption spectraphotometer (Perkin-Elmer Model HO-214). Results are shown in the table below.
Table 3______________________________________ Serum calcium (mg/100 ml)Compound Given 8 h 24 h______________________________________Control 7.7 ± 0.2*.sup.(a) 3.9 ± 0.1.sup.(a)24F.sub.2,25-OHD.sub.3 4.9 ± 0.2.sup.(b) 5.2 ± 0.2.sup.(b)25-OHD.sub.3 4.7 ± 0.3.sup.(b) 5.3 ± 0.2.sup.(b)Significance (b) from (a) (b) from (a)of difference ρ<0.001 ρ<0.001 *Standard derivative of the mean
Antirachitic Activity
Male weanling rats (Holtzman Co., Madison, Wisconsin) maintained in hanging wire cages were fed, in groups of six the low phosphorous diet described in Am. J. Physiol 204, 833 (1963) (Guroff, DeLuca and Steenbock) and were simultaneously given either 24F 2 , 25-OHD 3 dissolved in 0.1 ml ethanol/propylene glycol (5/95, v/v) subcutaneously every day for two weeks. Rats in the control group were fed in like manner but received only the vehicle subcutaneously.
Twenty-four hours after receiving the last subcutaneous dose the rats were killed by decapitation and their duodena were used for measurement of intestinal calcium transport as described above. Their radii and ulnae were removed for measurement of widened epiphyseal plates, and femurs for determination of ash content (femurs were dried to constant weight and then ashed in a muffle furnace at 650° C. for 8 hours.)
Results obtained are shown in the table below.
Table 4__________________________________________________________________________Compound Dosage Intestinal Calcium Width of Epiphyseal Femur AshGiven (ρmole) Transport (I/O) Plate (mm) Total (mg) PercentControl 2.1 ± 0.3*.sup.(a) 3.2 ± 0.3.sup.(a) 29.71 ± 3.06.sup.(a) 27.3 ± 224F.sub.2,25-OHD.sub.3 6.5 5.7 ± 1.2.sup.(b) 1.5 ± 0.2.sup.(b) 37.53 ± 3.82.sup.(b) 30.9 ± 1.1 6.5 11.2 ± 2.3.sup.(c) 0.5 ± 0.1.sup.(c) 52.95 ±3.55.sup.(c) 38.5 ± 1.125-OHD.sub.3 6.5 5.4 ± 0.3.sup.(d) 1.5 ± 0.3.sup.(d) 39.83 ± 6.31.sup.(d) 31.7 ± 2 6.5 10.8 ± 2.0 .sup.(e) 0.6 ± 0.2.sup.(e) 53.66 ± 6.72.sup.(e) 38.4± 2.7*Significance (b),(c),(d), & (e) (b) from (a) (b) from (a) (b) fromof difference from (a) ρ<0.005 ρ<0.005 ρ<0.01 ρ<0.001 (d) from (a) (d) from (a) (d) from ρ<0.025 ρ<0.025 ρ<0.025 (c) & (e) from (a) (c) & (e) from (a) (c) & (e) ρ<0.001 ρ<0.001 from (a) ρ<0.00__________________________________________________________________________ *Standard derivation of the mean
Male weanling rats were fed the low phosphorous diet referenced above and then divided into groups of five or six rats each. The rats in each group were given respectively a single dose (as shown in the table below) of either 24F 2 ,25-OHD 3 or 25-OHD 3 dissolved in 0.05 ml of 95% ethanol intrajugularly. Rats in the control group received the ethanol vehicle above. 168 hours after receiving the indicated dosage the rats were killed by decapitation, the blood of each group was collected and the radii and ulnae were removed to determine antirachitic activity in accordance with the rat line test (U.S. Pharmacopoeia, 15th Rev., Mack Publishing Co., Easton, Pa., 1955, p. 889). The blood was centrifuged immediately after collection to yield the serum. The inorganic phosphorous in the serum was determined by the method of Chen et al (Anal. Chem., 28, 1756, (1956)).
Results obtained are shown in the table below.
Table 5______________________________________ Serum InorganicCompound Dosage Phosphorous Line Test ScoreGiven (ρmole) (mg/100 ml) (Unit)______________________________________Control 1.6 ± 0.2*.sup.(a) 024F.sub.2,25-OHD.sub.3 130 3.0 ± 0.2.sup.(b) 4.4 ± 1.4.sup.(a) 325 3.5 ± 0.4.sup.(b) 525-OHD.sub.3 130 3.3 ± 0.1.sup.(b) 2.6 ± 0.6.sup.(b) 325 3.6 ± 0.4.sup.(b) 3.5 ± 0.6Significance (b) from (a) (b) from (a)of difference ρ<0.001 ρ<0.025______________________________________ *Standard deviation of the mean
To determine the antirachitic activity in response to a daily dose of 24F 2 ,25-OHD 3 rats were fed the low phosphorous diet referenced above for three weeks. They were then given either 24F 2 ,25-OHD 3 or 25-OHD 3 (in each case, 65 ρ mole dissolved in 0.1 ml ethanol/propylene glycol (5/95, v/v) subcutaneously every day for 8 days while being maintained on the same diet (9 rats were in each group). The rats in the control group (4 rats) were given only the ethanol/propylene glycol vehicle in the same manner.
Twenty-four hours after receiving the last dose they were killed and their radii and ulnae were removed and used for measuring antirachitic activity (rat line test, supra) while the femurs were removed and ashed as described above.
Results obtained are shown in the table below.
Table 6______________________________________Compound Line Test Total Femur Ash Percent AshGiven Score (Unit) (mg) (%)______________________________________Control 0 23.80 ± 3.98*.sup.(a) 19.5 ± 3.4.sup.(a)24F.sub.2,25-OHD.sub.3 >>5 37.03 ± 4.94.sup.(b) 26.2 ± 1.8.sup.(b)25-OHD.sub.3 >>5 38.56 ± 5.79.sup.(b) 27.4 ± 2.4.sup.(b)Significance (b) from (a) (b) from (a)of difference ρ<0.001 ρ<0.005______________________________________ *Standard deviation of the mean
It is evident from the foregoing data that 24,24-difluoro-25-hydroxy vitamin D 3 exhibits pronounced vitamin D-like activity and appears to be wholly as effective in this regard as 25-hydroxy vitamin D 3 (see U.S. Pat. No. 3,565,924).
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The invention provides a new derivative of vitamin D 3 , 24,24-difluoro-25-hydroxycholecalciferol.
The compound is characterized by vitamin D-like activity in its ability to increase intestinal calcium transport, increase serum calcium and inorganic phosphorous concentration and to prevent the development of rickets. It would find ready application as a substitute for vitamin D 3 and in the treatment of disease states evincing calcium-phosphorous imbalance and which are non-responsive to vitamin D 3 therapy.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 12/461,482, filed Aug. 12, 2009, which claims priority to U.S. Provisional Patent Application No. 61/188,727, filed Aug. 12, 2008.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a location-based recovery device and risk management system for portable computing devices and data.
[0004] 2. Related Art
[0005] With the advent of telecommunications, it has become useful and desirable for enterprises and individuals to employ various forms of sensors and communications devices to monitor the condition and location of certain assets such as portable computing devices. Advances in digital, electronic and wireless communication devices have extended the range and convenience of portable asset monitoring. Global Positioning Satellites (GPS) such as Inmarstat, Iridium, Globalstar, or Msat now increase the accuracy of portable asset location and movement. Such technologies are significant in improving efficiency and economic management of portable assets. Such devices and business practices are well known in the prior art.
[0006] There are approximately a dozen disclosures describing GPS features that relate to portable device theft and recovery that constitutes the known prior art relating to the present invention. The present invention provides novel and useful improvements, methods and processes for reducing economic and property losses related to the theft or loss of portable computing devices which, without limitation, is distinguished from the prior art in the following discussion.
[0007] In U.S. Patent Publication No. 2006/0007039, a method and system arc disclosed for expanding law enforcement recovery efforts for missing vehicles using VHF enabled networks and concealed GPS receivers. The present invention application is distinguished in that its hardware elements are novel and unique to the small dimensions of a portable computing device. A further limitation of the prior art is that it substantially provides only passive tracking capabilities. An improvement of this invention over the prior art is the novel enablement of the tracking device to receive and initiate certain limited and useful operations of the stolen or missing computing assets to prevent unauthorized use of its digital content.
[0008] U.S. Patent Publication No. 2004/0198309 discloses a stolen vehicle tracking and recovering method that utilizes cellular telecommunication networks for providing location guidance information to improve vehicle recovery. An improvement of the present invention over the prior art is its use of an implanted GPS device within a portable computing device that communicates directly with a global positioning satellite network and independently of the operating system of the portable computing device.
[0009] In U.S. Patent Publication No. 2003/0005316, the prior art teaches a mobile system that is provided with a theft recovery mechanism comprising a host chipset and a locator subsystem connected to the host chipset that is arranged to determine a current location of the mobile system; and a main storage connected to the host chipset and arranged to store an operating system (OS) and contain an OS-Present application and/or a Pre-OS application configured to enforce security policies during user authentication and determine whether the mobile system may have been stolen or used inappropriately based on the security policies. A novel improvement of the present invention is its use of an implanted autonomous device that coordinates theft and tracking functions separate from an existing computing operating system. This improvement provides a measure of security from programming interference or compromise by software viruses that can attack and compromise mobile device operating systems.
[0010] In U.S. Pat. No. 5,793,283, titled “Pager Vehicle Theft Prevention and Recovery System”, the prior art teaches a theft prevention and recovery system using pager network for vehicles, which transmits a designated electronic alarm signal via free space through an electronic transceiver when a remote alarm activation signal is received. The user instructs the transceiver to transmit a continuous pager signal containing longitudinal and latitudinal coordinates generated by the GPS. The longitudinal and latitudinal coordinates allow the car to be traced and recovered. The present invention is distinguished from this prior art because its mode of operation configures to the unique parameters of a personal computing system, which contains data files. In the event of a loss or theft of the personal computing system, a novel improvement of the present invention is that it can determine and activate procedures on the data files if such data files must be cordoned off, destroyed, encrypted or transmitted to a remote and secure location.
[0011] Other prior art is disclosed in U.S. Patent Publication No. 2007/0180207, which involves secure radio frequency identification (RFID) backup/restore for computing/pervasive devices. This prior art uses an automated RFID based data backup and recovery system for a computing device to invoke logic to initiate physical copying and transmission of digital storage device content to remote storage device. The present invention is distinguished by its separate universal GPS device that is installed in a portable computing device. Further the present invention requires positive activation by the user and can trigger disablement of the host computing device to prevent economic loss related to a potential disclosure breach of proprietary, personal or commercial data.
[0012] In U.S. Patent Publication No. 2006/0033616, titled “Smart Container Gateway”, the prior art comprises a smart container gateway that provides communication with global and local networks, container and cargo security sensors and cargo identification tags. The smart container gateway communicates with one or more networks by means of an integrated structural RF antenna, power generator and radio control subsystem. The present invention is distinguished in that its application requires insertion of a compact and covert device into the interior space of the portable computing device and requires external power from the host device and external activation prior to performing or activating to perform any function.
[0013] In U.S. Patent Publication No. 2005/0017900, titled “Tracking Unit”, the prior art describes a tracking unit for assisting in the recovery of stolen monies or other property includes a housing containing a GPS receiver for receiving GPS signals from overhead satellites, a cellular phone transceiver, a microprocessor, and a battery. Following a theft, the microprocessor activates the cellular phone transceiver to dial the telephone number of a central monitoring station. The present invention is distinguished in that it is directly installed into the theft risk (i.e. the portable computing device) in which it is installed.
[0014] In U.S. Patent Publication No. 2004/0075539, titled “Vehicle Monitoring System”, the prior art discloses “remote theft monitoring for vehicle by sensing vehicle displacement, engine operation and key entry.” When a possible theft condition is determined, the service provider server will generate a message to alert a security agency. The present invention disclosure is distinguished by its use in portable computing devices and its requirement for active external activation by an owner to operate its novel features and benefits.
[0015] In U.S. Pat. No. 6,049,269, titled “Wide Area Wireless System for Access Into Vehicles and Fleets for Control, Security, Messaging, Reporting and Tracking”, the prior art invention uses a paging signal initiated by owner if his or her vehicle is stolen, on-board paging receiver, decoder, controller, alarm and ultimate disablement of vehicle. The present invention is an improvement in its use of a novel software based method that employs an insertable GPS device into portable computing devices. In the present invention, a novel software based method computes a GPS system purchase price related to the savings from economic loss by recovery or by cash compensation in the event of an unrecoverable loss of said portable computing device.
[0016] Notwithstanding the prior art discussed herein, the invention is novel because none of the prior disclosures either alone or in combination are sufficient to disclose the invention set forth in this application. As a result, the present invention offers numerous advantages over the prior art, including, without limitation:
[0017] a) The claimed invention discloses a novel and useful GPS device and antennae system that may be covertly and efficiently installed into a portable computing device.
[0018] b) The invention is a novel means to employ software in the GPS device that may instruct the portable computing device to transmit, alter or destroy data files in the portable computing device to prevent loss of economic value or personal privacy.
[0019] c) The invention is a novel software based method and financial system to acquire and install such a GPS device and software and to provide an insurance product to compensate for loss by the theft of or accidental loss of portable computing devices. From the discussion that follows, it will become apparent that the present invention addresses the deficiencies associated with the prior art while providing numerous additional advantages and benefits not contemplated or possible with prior art constructions.
SUMMARY OF THE INVENTION
[0020] A location-based recovery device and risk management system for portable computing devices and data is disclosed herein. The location-based recovery device and risk management system both protects data stored on portable computing devices and assists in the location and recovery of portable computing devices that have been stolen or otherwise lost. The stored data may be overwritten or encrypted for later decryption when the portable computing device is recovered. In this manner, such data is protected even when the portable computing device is lost.
[0021] Various embodiments of the location-based recovery device and risk management system are disclosed herein. For instance, in one exemplary embodiment, the location-based recovery device and risk management system may be a portable computing device comprising a power source configured to allow operation of the portable computing device without being connected to an electrical outlet, a data storage assembly configured to store one or more data files on the portable computing device, and a wireless communication assembly.
[0022] The wireless communication assembly may be configured to receive one or more wireless signals to determine a geographic location of the portable computing device, receive input indicating the theft or loss of the portable computing device, and transmit the geographic location of the portable computing device after receiving the input indicating the theft or loss of the portable computing device.
[0023] Upon receiving one or more particular wireless transmissions, the data storage assembly modifies the data files utilizing a random binary fill or encryption that is capable of decryption if the portable computing device is recovered. This protects the data files on the portable computing device. It is contemplated that the particular wireless transmissions may only be transmitted by an authorized user of the portable computing device.
[0024] It is noted that the wireless communication assembly may have various configurations. For example, the wireless communication assembly may comprise a GPS device, a cellular data transceiver, a Wi-Fi data transceiver, or various combinations thereof in one or more embodiments.
[0025] In another exemplary embodiment, the location-based recovery device and risk to management system may be a data protection and recovery system for a portable computing device (e.g., a laptop, tablet, or smartphone). Such system may comprise one or more communication devices configured to send one or more transmissions to the portable computing device indicating the theft or loss of the portable computing device, wherein the portable computing device is configured to, upon receipt of one or more particular transmissions, modify data stored thereon utilizing a random binary fill or encryption that is capable of decryption if the portable computing device is recovered. The communication devices will typically also be configured to receive a response from the portable computing device indicating the geographic location of the portable computing device.
[0026] A user interface of the system may query a user whether to activate data file management on the portable computing device. Upon receiving user input activating data file management, the communication devices transmit the particular transmissions thereby causing the portable computing device to modify the data stored thereon utilizing a random binary fill or encryption that is capable of decryption if the portable computing device is recovered. The particular transmissions may be received wirelessly by the portable computing device. It is noted that the communication devices may be further configured to transmit one or more instructions to the portable computing device to decrypt encrypted data store thereon.
[0027] The user interface may be further configured to query the user whether to activate file management comprising the random binary fill or encryption that is capable of decryption if the portable computing device is recovered. In addition, it is contemplated that the user must be an authorized user of the data protection and recovery system in order to utilize the system's capabilities.
[0028] Various methods for data protection and recovery for a portable device are disclosed herein as part of the location-based recovery device and risk management system as well. For instance, in one exemplary embodiment, a method for data protection and recovery for a portable device may comprise providing a data storage device configured to store data on the portable device and to modify the stored data utilizing a random binary fill or encryption that is capable of decryption and data recovery if the portable device is recovered, and wirelessly receiving input indicating the theft or loss of the portable computing device via a signal reception and transmission assembly of the portable computing device. Upon receiving the particular wireless transmissions, a geographic location of the portable computing device is determined and reported to a user via the signal reception and transmission assembly.
[0029] In the method, modification of the stored data utilizing a random binary fill or encryption that is capable of decryption and data recovery if the portable device is recovered is conditioned upon receipt of one or more particular wireless transmissions by the signal reception and transmission assembly.
[0030] It is noted that the method may further comprise installing a GPS device, cellular data transceiver, Wi-Fi data transceiver, or various combinations thereof in the portable device as part of the signal reception and transmission assembly. Similar to above, it is contemplated that the particular wireless transmissions may only be transmitted by an authorized user of the portable device.
[0031] Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.
[0033] FIGS. 1A-1C are exemplary schematics illustrating the elements of the invention device in various view planes that demonstrate the composition of electrical and structural elements necessary for installation into a portable computing device.
[0034] FIG. 1A is a frontal plane view of said exemplary device.
[0035] FIG. 1B is a back plane view of said exemplary device.
[0036] FIG. 1C is a side view of said exemplary device.
[0037] FIG. 2 is an exemplary process and software block flow diagram for use of the installed exemplary device of FIGS. 1A-C in the event of theft or loss of the portable computing device to which the device is covertly affixed.
[0038] FIG. 3 is a block diagram illustrating a preferred embodiment of the method and system disclosed by the present invention which respects to, purchase, registration, signal generation, tracking and control of the installed exemplary device of FIGS. 1A-1C .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] In the following description, numerous specific details are set forth in order to provide a more thorough description of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without these specific details. In other instances, well-known features have not been described in detail so as not to obscure the invention.
[0040] Due to the growth of the Information Technology (IT) infrastructure and general decrease in costs and sizes of GPS device components, there has been a growing demand for GPS implementation within portable assets, such as portable computing devices. As individuals and enterprises expand the use of portable computing devices such as with laptop, tablet, and handheld computers (e.g., smartphones), there has been an increasing recognition of the vulnerability such devices have for theft or loss and the corresponding increase in economic value and corresponding loss when theft or loss occurs. For example, of the more than 10,000 laptops that go missing every month at Chicago O'Hare Airport, approximately only 22% are ever recovered.
[0041] A problem in the prior art has been an inability to configure and fabricate GPS devices that were compact enough to conveniently install on portable computing devices. A further problem is the inability to configure an embedded antennae configuration with such a compact GPS device that will reliably transmit such signals usable by a GPS tracking network for device recovery in the event of theft or loss. A still further problem has been a lack of means to configure such GPS devices for simple, rapid and covert installation into existing portable computing devices that will be both efficacious yet difficult to detect and disable by thieves. A still further problem in the prior art is the lack of an enabling system to instruct the installed GPS device in a portable computing device to instruct the computing device to transmit, alter or destroy stored data files to prevent economic loss or breach of privacy rights. A still further problem is the lack of a suitable business method and process to price, acquire and install such GPS devices, concurrent with a method to price and provide a risk management financial instrument to compensate a purchaser for potential the risk of loss and impairments occasioned by the irrecoverable or partial recovery of portable computing devices and data therein installed.
[0042] Currently, GPS is a fast-growing field. For instance, cell phones currently have the ability to have GPS on them, as do automobiles, thereby giving GPS products off-the-shelf availability. However, in the present invention, the device's solutions and implementation, and the size of the unit make it unique. In addition, the present invention includes a novel, computationally based recovery replacement program that utilizes a generated insurance service to mitigate the risks and costs associated with theft and loss of portable computing devices.
[0043] Therefore, a first object of the present invention is to disclose a novel and useful GPS device and antennae system that may be covertly and efficiently installed into a portable computing device through the memory slots on the motherboard.
[0044] A second further object of the invention is to disclose a novel means to employ specific software (referred to herein as “Silver Bullet software”) in the GPS device that may independently instruct the portable computing device to transmit, alter or destroy data files in the portable computing device to prevent loss of economic value or personal privacy through the unique coding of the Silver Bullet software application.
[0045] A third further object of the present invention is to disclose a novel computerized and enabled method to acquire and install such a GPS device and software and to provide a computer generated insurance product to compensate for accidental loss or theft of such portable computing devices.
[0046] The present invention is embedded into the portable computing device via au open card slot on the motherboard of said portable computing device, which is respectively illustrated in the diagrams of FIGS. 1A , 1 B, and 1 C. In a preferred embodiment, the device is always powered on, even when the portable computing device is not plugged in. The power drain is minimal due to the fact the device is in “sleep mode” and allows for a SMS message to be sent to the device on demand and therefore locating the portable computing device with accuracy within 5 meters.
[0047] Unlike prior art products that are required to be connected to the Internet, the present invention can be located on demand regardless of whether or not the portable computing device is plugged in or connected to the Internet. A SMS text message is sent to the device and it responds with longitude/latitude parameters of its locations. These parameters are entered into a mapping software system and locate the device and display its location on a map of the area within 5 meters of accuracy.
[0048] In contrast, prior art devices are typically embedded into the systems BIOS and can only be located from internet “hotspots” such as Starbucks coffee, bookstores and other wired locations, etc. This means the portable computing device can only be located from an internet connection in which it is connected therefore no on demand capability exist with the prior art products and, therefore, are less accurate.
[0049] The present invention incorporates other novel features as well. For example, if desired by the owner, a transmitted message to the Silver Bullet software can be sent to and through the present invention to destroy the data contained on the hard drive rendering the portable computing device useless. The Silver Bullet software function will issue a command to the present invention that will activate a binary overwrite command that will fill the entire hard drive with 1's and 0's rendering the portable computing device useless and even unable to boot up since the operating system will also be overwritten. Prior art products do not offer or anticipate this capability.
[0050] Furthermore, in the unlikely event the portable computing device is not recovered within a definite time (e.g., 15 calendar days), the risk management process of the present invention will electronically commence an order, payment and shipment process to replace the portable computing device with a comparable product of like, kind and quality or better. Additionally the risk management process can also electronically provide compensation to the owner for the lost economic value of the data files stored on the unrecovered portable computing device.
[0051] It will be obvious to one skilled in the art that the invention may take numerous forms of device and system configurations that will accommodate a diversity of covert GPS tracking devices, portable computing devices, and electronically implemented, software-based insurance and purchase business systems. What follows is a preferred embodiment of the useful novelties of the present invention. However, for one skilled in the art it will be obvious that the novel features disclosed herein may be employed with equal utility to alternate configurations of the invention elements.
[0052] The disclosed invention is the GPS personal tracking and recovery device used inside of laptops and other types of portable computing devices. In a preferred embodiment with this type of system, a battery or power source is required. If the device is charged using its internal battery it typically has four hours of run time and three days of standby time. However, if the invention device is charged using the laptop power source in which the invention device was installed, that device can operate efficiently using inside power as long as that power is available. In some cases, people will disconnect the power and/or repackage. However, when it becomes time to re-engage power, the invention device will begin transmitting again and has been set on a protocol that allows the user to continue to transmit immediately. If somebody attempts to change the exterior of the portable computing device, the invention's embedded chip will still react.
[0053] Referring now to FIG. 1A , the exemplary invention is shown in frontal plane view. At 100 the flexible antenna for GMS transmission is displayed. At 102 , a GPS antenna is displayed. A telephone modem 104 provides for reception and transmission of software enabled data and instructions between the invention device and a remote invention user. A GPS transmitter 106 enables the invention device to transmit and obtain location signals from a GPS/GSM array. A SIMM card housing and apparatus 108 together with the modem 104 , antennae 102 , 100 and the GPS transmitter 106 are affixed and communicate with a circuit board 110 . In the present embodiment, the circuit board 100 is in signal communication with the computing element of portable computing device through a connector rail 112 . The circuit board 110 has an electric power connection with the portable computing device at 114 .
[0054] Referring now to FIG. 1B is a back plane “through view” of the exemplary invention which was previously referenced in FIG. 1A . The invention illustrated in FIG. 1B maintains the same orientation as FIG. 1A and the observer views the back plane view through the front plane orientation. The conspicuous feature of FIG. 1B is a rechargeable battery element 118 , affixed to the circuit board 110 , which communicates with external recharging power through the battery recharge port at 114 .
[0055] Referring now to FIG. 1C is an alternative side view of the invention device illustrating an alternative positioning of some of the invention device elements. More specifically, the circuit board 110 is shown housing various communication circuit elements 120 within the circuit board 110 itself. The flexible antenna 100 is mechanically affixed to the rechargeable battery 118 . The connector rail 112 and battery recharge port elements are deliberately omitted in the plane view to highlight other invention elements. However, for one skilled in the art such alternate assemblies are well understood and frequently used to minimize overall device size and/or connection compatibility to the portable computing device. Further, flexibility in the invention device element assembly lends itself to covert design in either imitation of other circuit elements or compact size. Either option is novel and useful in preventing invention device tampering or detection.
[0056] For this exemplary application, the invention tracking device will be used inside of a laptop computing device, deriving its power source directly from said computer's battery source as shown at 114 in FIGS. 1A and 1B respectively. The invention device allows the laptop owner to use either a desktop computer, a third party tracking service and/or a cellular phone for immediate tracking capability. Additionally, once the invention device registers the laptop as missing, an owner has the ability to initiate regular monitoring whereby, for example, the installed device can transmit a location, based upon plain sight, every two minutes up to every 24 hours.
[0057] This invention's tracking device is useful because of the fact that there is a high theft and low recovery rate of laptops. An additional novel benefit is that this invention device can be used in almost any type of device which utilizes an AC/DC power source and which can be converted to the 12-volt standard typically required. The usefulness of this device is self-evident with the ability to recover misplaced or stolen products through the ability to have immediate real-time access based upon GPS satellite transmission.
[0058] FIG. 2 is a block diagram indicating an exemplary software enabled process utilizing the tracking device. Such a process starts 200 with physical installation of the device at a step 205 , referenced in FIGS. 1A-C . Concurrently at step 205 , the software components are installed in the invention device and a covert tracker device 225 such as a desktop computer, cellular phone or a telecommunications service provider system. The enabled covert tracking device system remains dormant at a step 210 until activation by a transmitted request from the owner or authorized user to an operational covert tracker device. An activation of the installed device at a step 215 results in a query at a decision step 220 on whether to activate the tracking program routine. A “no” response at decision step 220 returns the installed device to a dormant mode at step 210 . A “yes” at decision step 220 requires manual activation of the software elements to activate tracking operations at a step 225 through transmission and detection of GPS location coordinates at a step 230 . Upon activation, the owner or authorized user is queried as to whether to commence data file management via the installed tracker device at a decision step 235 . A “no” at decision step 235 returns either to the decision step 220 tracker query option or to automated tracking at step 225 that continues periodic detection and transmission of GPS location coordinates. A “yes” at decision step 235 is indicative of a threat that data on the portable computing device is at risk of unauthorized use or unacceptable loss. A “yes” at decision step 235 thus queries the owner or authorized user to encrypt or destroy portable computing device data files at a decision step 240 . If the “destroy” option is authorized, the invention initiates its Silver Bullet software routine to overwrite and destroy portable computing device data files. It will be obvious to one skilled in the art that the Silver Bullet software may also be used to uninstall or disable stored software programs, protocols or operating systems deemed proprietary and a cause of economic loss in the event of loss or imminent unauthorized use of the portable computing device. If the encrypt option is selected at decision step 240 then the owner/authorized user is queried whether to transmit such data files at a decision step 245 . If a “yes” occurs at decision step 245 then the installed tracking device uploads and sends such files to the activation location at a step 250 . If an owner successfully recovers the portable computing device at a decision step 260 , the tracking routine ends and the system is returned to its initial settings of the dormant state at step 210 . If the laptop or data are not recovered within a definite time at decision step 260 , the owner then electronically files an insurance claim at a step 265 , which makes compensation to the owner for loss. Upon replacement of the lost hardware, the user process returns to step 205 for installation and protection of the replacement device.
[0059] Referring now to FIG. 3 , a preferred embodiment of the method of the present invention is shown. A laptop computer owner 360 who will own or owns a portable laptop 330 will procure the covert GPS device 320 in connection with a purchase agreement that incorporates an insurance policy related to a future event involving theft or loss of laptop 330 . The policy will be produced using a novels series of software algorithms that utilize, without limitation, a plurality of data inputs; the cost of GPS device 320 , the cost of installation of GPS device, the cost of monitoring service 340 , the cost of communications from monitoring service to GPS satellite array 310 , the cost of communication of the GPS satellite with covert GPS device 320 , a future time based value of information and data maintained or to be maintained on laptop 330 for which owner 360 will be compensated in the event of theft or loss of laptop. The payments made by laptop owner 360 to insurer 350 may be a lump sum or a series of fixed or variable payments. The covert GPS device 320 will be installed by a certified contractor and will place the covert device into laptop 330 in a manner that makes it difficult to recognize the covert device as other than the normal hardware of laptop. The contractor will also connect the covert device power receptacle to the power system of laptop 330 . The contactor will enable an anti tampering feature of covert GPS device 320 to trigger an alarm or automatic transmission signal as part of the security protection features of the invention. The covert GPS device 320 will be electronically enabled using embedded software algorithms that may also be encrypted to provide security to the owner 360 and an identifier code for monitoring service 340 and GPS satellite array 310 . In the event of a theft or loss of laptop 330 , owner 360 will communicate the event to insurer 350 . Insurer 350 will communicate with service 340 to initiate a tracking algorithm to locate laptop 330 . Alternately, the owner 360 call report will be automatically forwarded to monitoring service 340 . GPS device 320 will receive an enabling transmission from GPS Satellite 310 and commence periodic GPS location emissions using power derived from laptop 330 power source.
[0060] In a further variation of the invention, the monitoring service 340 will manually or automatically transmit to the GPS satellite array 310 an authorization for covert device 320 to initiate a wireless data transmission of files stored on laptop 330 to secure files managed by the monitoring service 340 . These files will be forwarded under secure transmission or recorded on to a suitable data storage medium for physical delivery of such data files stored on laptop 330 to owner 360 . In a still further variation of the invention the instructions regarding data stored on laptop 330 may instruct the laptop to alter or eradicate such stored files.
[0061] In summary and without limitation, the invention is comprised of the following elements:
[0062] A first element consisting of fabricating an installed covert tracking device further comprised of circuit, electronic and power elements as shown in FIGS. 1A , 1 B, and 1 C that is compatible with the portable computing device into which it is installed;
[0063] A second element where said covert tracking device is acquired in conjunction with a software generated insurance policy and tracking system to mitigate the risk of loss of a portable computing device into which said covert tracking device is installed;
[0064] A third element of installing the covert tracking device covertly inside the portable computing device and further attaching it to the power source and/or battery of said portable computing device where said tracking device itself does not rely on any functions from the portable computing device and is stand-alone other than the power source;
[0065] A fourth element where, once the tracking device is installed in the portable computing device, and in the event for whatever reason the portable computing device is misplaced and or stolen, an owner of the lost portable computing device will have the ability to telecommunicate to activate a recovery protocol utilizing the tracking features of the covert tracking device;
[0066] A fifth element where recovery of all portable computing devices using this tracking device invention is based upon real-time GPS locations and, in the event recovery is not immediate, the tracking device itself receives a communication that allows the tracking device to power on and regularly source and transmit GPS location data until actual recovery or determination of an unrecoverable loss of said portable computing device.
[0067] A sixth element where a portable computing device being misplaced or stolen, a certain minimum time must lapse (e.g., 5 days) before it is deemed unrecoverable. If the portable computing device is not recovered within the lapsed period, a risk management underwriter will be obligated, through said insurance policy, to replace the unrecovered portable computing device together with a compensable sum for the economic loss of proprietary data files.
[0068] It will be obvious to one skilled in the art that this invention device, method and process apply to numerous other types of portable computing devices. The immediate invention opportunity appears to be with laptops, as there is apparently a unique and unmet need to mitigate sensitive and valuable data storage and restriction issues in the event of loss or theft of the portable computing device.
[0069] While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of this invention. In addition, the various features, elements, and embodiments described herein may be claimed or combined in any combination or arrangement.
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A device and software utilizing Global Positioning Satellite (GPS) technologies for monitoring and recovering portable computing devices and, a method and system for acquiring such devices, protecting data on such devices, and for compensating owners of devices. A GPS mechanism of the invention provides real time tracking of missing devices that may be coordinated with security agencies to intercept and recover missing computing devices. When a stolen device is unrecoverable, the invention may receive a signal to initiate data recovery where a wireless network is available to recover data for the owner. Alternatively, the GPS mechanism instructs the device to encrypt or destroy stored data files to prevent commercial espionage or privacy violations. The invention discloses a software system and method for computing a purchase price of the GPS mechanism, computing compensation for loss of the device and lost data.
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CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/398,461, filed on Jun. 25, 2010, which is hereby incorporated by reference in its entirety.
BACKGROUND
1. Field of the Invention
The field of the invention relates to roofing materials, and more particularly to methods and systems for spacing panels on roofs.
2. Description of the Related Art
Roofs cover the uppermost part of a space or building, protecting the space or building interior from rain, snow, wind, cold, heat, sunlight, and other weather effects. Many roofs are pitched or sloped to provide additional protection against the weather, allowing rain or snow to run off the angled sides of the roof. Roofs generally include a supporting structure and an outer skin, which can be an uppermost weatherproof layer. The supporting structure of a roof typically includes beams of a strong, rigid material such as timber, cast iron, or steel. The outer layer of a roof can comprise panels or boards constructed of timber, metal, plastic, vegetation such as bamboo stems, or other suitable materials.
In some cases, a pitched roof is desired to shield a space against elements such as rain or snow, while still admitting light into the space and allowing air to freely circulate through the roof and into the space. Thus, methods and systems to efficiently and reliably attach an outer skin to the supporting structure of a roof such that the roof shields against weather elements, admits light, and allows advantageous air circulation are desired and remain a significant challenge in the design of roofing systems.
SUMMARY OF CERTAIN EMBODIMENTS
The systems, methods, and devices of the invention each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this invention, its more prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this invention provide advantages over other roofing systems.
Methods and devices for spacing panels on a roof are provided. In one embodiment, a wedge-shaped device for spacing panels on a roof includes a bottom surface; a top surface inclined at an angle α relative to the bottom surface; and an integral support structure connecting the top surface and the bottom surface. The support structure includes a plurality of support ribs and a plurality of nail boxes.
Another embodiment provides a method of installing roof panels on roof support beams. The method includes fastening a plurality of wedge-shaped spacers to a top surface of one or more roof support beams; and fastening a bottom surface of one or more roof panels to the spacers.
In yet another embodiment, a roof panel spacer system for constructing a roof is provided. The system includes a plurality of support beams; a plurality of spacers fastened to at least some of said support beams; and a plurality of roof panels fastened to the plurality of spacers. Each spacer orients each roof panel substantially horizontal to the ground. Each spacer is positioned to create a space between adjacent roof panels allowing air and light to pass through the roof. Each spacer is also positioned to create an overlap between adjacent roof panels, inhibiting rain and other weather elements from passing through the roof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a top perspective view of an embodiment of a roof panel spacer device.
FIG. 1B is a bottom perspective view of the device of FIG. 1A .
FIG. 1C is a bottom elevational view of the device of FIG. 1A .
FIGS. 2-7 illustrate the device of FIG. 1A in use on a roof.
FIG. 8 is a top elevational view of the device of FIG. 1A .
FIG. 9A is a side elevational view of the device of FIG. 1A .
FIG. 9B is a side elevational view of the device of FIG. 1A showing additional internal features.
FIG. 10A is a back elevational view of the device of FIG. 1A .
FIG. 10B is a back elevational view of the device of FIG. 1A showing additional internal features.
FIG. 11A is a bottom perspective view of another embodiment of a roof panel spacer device.
FIG. 11B is a bottom elevational view of the device of FIG. 11A .
FIG. 11C is a cross-sectional view of the device of FIG. 11A taken along line 11 C- 11 C of FIG. 11B .
FIG. 11D is a cross sectional view of the device of FIG. 11A taken along line 11 D- 11 D of FIG. 11B .
FIGS. 12-15 illustrate the device of FIG. 11A in use on a roof.
DETAILED DESCRIPTION
Any feature or combination of features described herein are included within the scope of the present invention provided that the features included in any such combination are not mutually inconsistent as will be apparent from the context, this description, and the knowledge of one skilled in the art. In addition, any feature or combination of features may be specifically excluded from any embodiment of the present invention. For purposes of summarizing the present invention, certain aspects, advantages, and novel features of the present invention are described herein. Of course, it is to be understood that not necessarily all such aspects, advantages, or features will be present in any particular embodiment of the present invention.
It is to be understood that embodiments presented herein are by way of example and not by way of limitation. The intent of the following detailed description, although discussing exemplary embodiments, is to be construed to cover all modifications, alternatives, and equivalents of the embodiments as may fall within the spirit and scope of the invention.
Roof Panel Spacer for Two-Sided Roof
FIG. 1A is a top perspective view of an embodiment of a roof panel spacer 100 according to the present invention. FIG. 1B is a bottom perspective view of the spacer 100 . FIG. 1C is a bottom elevational view of the spacer 100 . The spacer 100 generally has a width W measured along an x-axis of the spacer 100 , a length L measured along a y-axis of the spacer 100 , and a height H measured along a z-axis of the spacer 100 . The spacer 100 includes a top surface 102 ; a bottom surface 104 ; sides 106 , 108 ; a back 110 ; and a front 112 .
The height H of the spacer 100 can be measured at different locations along the spacer 100 . For example, the height of the spacer 100 at the back 110 can be H BACK , while the height of the spacer 100 at the front 112 can be H FRONT . Embodiments of the spacer 100 can be wedge-shaped. For example, the top surface 102 can be inclined at an angle α relative to the bottom surface 104 . Additionally, the bottom surface 104 can be inclined at an angle β relative to the back 110 . In some aspects, the top surface 102 is oriented at an angle of 90° or about 90° relative to the back 110 .
The spacer 100 can include an integral support structure connecting the top surface 102 and the bottom surface 104 . The support structure can include a plurality of support ribs. For example, the spacer 100 includes width ribs 130 , 132 extending along the width W of the spacer 100 between the sides 106 , 108 . The spacer 100 can also comprise a length rib 134 extending along the length L of the spacer 100 between the back 110 and the front 112 . Bottom surfaces of the ribs 130 , 132 , 134 can form all or a portion of the bottom surface 104 of the spacer 100 .
In some aspects, the support structure also includes a plurality of nail boxes. For example, the spacer 100 includes nail boxes 150 , 152 , 154 , 156 , which will be described in greater detail below with reference to FIGS. 8-10B . The nail boxes can be configured to accept nails or other fasteners. Some embodiments of the nail boxes 150 , 152 , 154 , 156 comprise a hollow tube extending from the top surface 102 and the bottom surface 104 . The nail boxes can be connected to the width ribs 130 , 132 via flanges 160 , 162 , 164 , 166 , respectively. The spacer 100 may also comprise a nail box 168 disposed in the length rib 134 . Other configurations are possible. For example, in some aspects, the spacer 100 may not comprise one or more of width ribs, length ribs, nail boxes, and/or flanges.
FIGS. 2-7 illustrate one embodiment of a spacer according to the present invention in use on a roof 268 . Referring now to FIG. 2 , a first spacer 200 according to one embodiment is positioned between a first support beam 270 and a roofing panel or board 275 . The support beam 270 includes a top surface 272 . The panel 275 comprises a top surface 276 and a bottom surface 278 . A second spacer 200 is also positioned between a second support beam 280 and the panel 275 . The support beams 270 , 280 can comprise portions of the support structure of a roofing system, and the panel 275 can comprise a portion of the outer skin of the roofing system.
A top surface 202 of the spacers 200 are adjacent to and contact the bottom surface 278 of the panel 275 , while a bottom surface 204 of the spacers 200 are adjacent to and contact the top surfaces 272 of the support beams 270 , 280 . Other configurations are possible. For example, in another embodiment, the top surface 202 of the spacers 200 may be adjacent to the support beams 270 , 280 and the bottom surface 204 of the spacers 200 may be adjacent to the panel 275 .
FIGS. 3 and 4 illustrate embodiments of the spacers 200 in use. The support beams 270 , 280 are inclined relative to a horizontal axis x of the roof 268 by an angle θ BEAM . The panel 275 is inclined relative to the horizontal axis x of the roof 268 by an angle θ PANEL . As described above, the spacers 200 are positioned between the panel 275 and the support beams 270 , 280 . Additional spacers 200 (not illustrated in FIGS. 3 and 4 , but illustrated in FIG. 5 ) are positioned between a panel 282 and the support beams 270 , 280 . An “n” number of panels can be positioned on the support beams 270 , 280 using the spacers 200 . Additionally, the panels 275 , 282 can be positioned on “n” number of support beams using the spacers 200 in order to construct the roof 268 .
In some embodiments, the spacers 200 are positioned on the support beams 270 , 280 such that the panels 275 , 282 are horizontal or substantially horizontal to the ground and θ PANEL is 0° or about 0°. The spacers 200 may be positioned on the support beams 270 , 280 such that a vertical space 284 separates the panels 275 , 282 . In the embodiment illustrated in FIG. 3 , for example, each of the adjacent panels on the roof 268 are separated by the vertical space 284 . The spacers 200 can be positioned along the support beam 270 at the same or substantially the same distance intervals, such that the vertical spaces 284 separating adjacent panels are the same or substantially the same. It will be understood, however, that the vertical space 284 separating adjacent panels of the roof 268 need not be the same or substantially the same across the entire roof 268 . The vertical spaces 284 can advantageously allow for air to enter the space underneath the roof 268 and circulate within the space. Advantageously, the vertical spaces 284 can also allow light to enter the space underneath the roof 268 .
In some aspects, the top surface 276 of the panel 275 and the bottom surface 278 of the panel 282 overlap in a region 286 . This overlap between adjacent panels 275 , 282 can advantageously restrict rain and other weather elements from passing through the vertical space 284 and entering the space underneath the roof 268 . For example, embodiments of spacers described herein can shield the interior of a building or other space below a roof from light rain and/or rain without horizontal wind.
Persons of skill in the art will understand that the spacers 200 can be used with roofs 268 of varying slope or pitch. For example, the support beams 270 , 280 may be less sloped relative to the horizontal axis x of the roof 268 (corresponding to a smaller beam angle θ BEAM than that illustrated in FIGS. 2-7 ), in which case the angle α of the spacer 200 may be decreased. Similarly, the support beams 270 , 280 may be more sloped relative to the horizontal axis x of the roof 268 (corresponding to a greater beam angle θ BEAM than that illustrated in FIGS. 2-7 ). In such cases, the angle α of the spacer 200 can be increased accordingly. Of course, it will be understood that beam angle θ BEAM may not be equal to the angle α of the spacer 200 .
FIG. 5 illustrates a plurality of spacers 200 use on adjacent panels 275 , 282 . For example, the panel 275 is spaced from the support beam 270 by a first spacer 200 , from the support beam 280 by a second spacer 200 , and from a support beam n BEAM by a third spacer 200 . The panel 282 is spaced from the support beam 270 by a fourth spacer 200 , from the support beam 280 by a fifth spacer 200 , and from the support beam n BEAM by a sixth spacer 200 . Each of the panels of the roof 268 can be spaced from the support beams in a similar manner.
FIG. 6 illustrates the vertical spaces 284 that can be provided between adjacent panels 275 , 282 according to some embodiments of the present invention. As described above with reference to FIGS. 3 and 4 , the vertical spaces 284 between adjacent panels of the roof 268 can allow air and light to enter through the roof 268 , while also preventing weather elements such as rain from entering the space below the roof 268 .
FIG. 7 illustrates a plurality of spacers 200 in use on the roof 268 . A spacer is provided at the interface between each panel and each supporting beam. As described above with reference to FIG. 3 , the top surface of a first panel and the bottom surface of a second, higher panel are horizontally overlapped such that rain and other weather elements falling in a vertical direction do not enter the vertical spaces 284 and penetrate the space below the roof 268 .
Embodiments of the spacers 200 can advantageously be used to construct two-sided roofing structures. For example, the roof 268 illustrated in FIGS. 2-9 comprises a first side 288 and a second side 290 . The spacers 200 are positioned between support beams and panels on the first side 288 , as well as between support beams and panels on the second side 290 .
FIG. 8 is a top elevational view of the spacer 100 . FIG. 9A is an elevational view of the side 106 of the spacer 100 , illustrating internal features in dashed lines. FIG. 9B is an elevational view of the side 106 showing additional internal features such as the width ribs 130 , 132 . FIG. 10A is an elevational view of the back 110 of the spacer 100 , illustrating internal features in dashed lines. FIG. 10B is an elevational view of the back 110 illustrating additional internal features, including ribs and nail box features.
As described above with reference to FIGS. 1A-1C , the spacer 100 can include nail boxes 150 , 152 , 154 , 156 , and 168 . In one embodiment, the nail box 150 comprises a recessed area 151 and the nail box 152 comprises a recessed area 153 . The recessed areas 151 , 153 can accommodate the head of a nail or other fastener disposed in nail boxes 150 , 152 , respectively. It will be understood that other nail boxes of the spacer 100 can comprise recessed areas, and that the spacer 100 need not comprise any recessed areas around the nail boxes.
Referring now to FIG. 9A , the bottom surface 104 of the spacer 100 may be inclined at an angle α relative to the top surface 102 . The angle α can be between about 10° and about 25°. In one embodiment, the angle α corresponds to the angle θ BEAM of the support beams of the roof relative to a horizontal axis x of the roof. Where α equals θ BEAM , the top surface 276 of the panels of the roof may lie substantially horizontally on the spacers, such that the angle θ PANEL of the panels relative to the horizontal axis x of the roof is 0° or about 0°.
Additionally, the bottom surface 104 can be inclined at an angle β relative to the back 110 . The angle β can be between about 80° and about 65°. In the embodiment illustrated in FIG. 9A , angle α is about 18° and the angle β is about 72°. Other configurations are possible. For example, for a roof comprising support beams disposed at an angle θ BEAM of 20°, the spacer 100 can be modified such that the angle α is 20° and the angle β is 70°.
FIGS. 10A and 10B show additional views of the spacer 100 . FIG. 10A illustrates nail boxes 150 , 152 , 154 , 156 , 168 , as well as recessed areas 151 , 153 in dashed lines. FIG. 10B illustrates rib 134 in dashed lines.
FIG. 1A illustrates advantageous dimensions of certain specific embodiments of the spacer 100 . For example, the top surface of the spacer 100 is about 6 inches by about 4 inches; and the back 110 is about 4 inches by about 2 inches. Persons of skill in the art will understand that other dimensions are possible, and embodiments of the spacer 100 are not limited to the number or configuration of nail boxes shown, or the dimensions of spacer 100 .
Roof Panel Spacer for Roof with Three or More Sides
FIG. 11A is a bottom perspective view of an embodiment of a roof panel spacer 1300 according to the present invention. FIG. 11B is a bottom elevational view of the spacer 1300 . FIG. 11C is a cross-sectional view taken along line 11 C- 11 C of FIG. 11B . FIG. 11D is a cross-sectional view taken along line 11 D- 11 D of FIG. 11B . Embodiments of the spacer 1300 can be used to construct roofing structures with three or more sides.
The spacer 1300 generally has a width W measured along an x-axis of the spacer 1300 , a length L measured along a y-axis of the spacer 1300 , and a height H measured along a z-axis of the spacer 1300 . The spacer 1300 includes a first top surface 1302 A; a second top surface 1302 B; a bottom surface 1304 ; and sides 1306 , 1308 , 1310 , 1311 , 1312 , and 1313 . In some aspects, the spacer 1300 includes a peaked top surface.
The height H of the spacer 1300 can be measured at different locations along the spacer 1300 . For example, the height of the spacer 1300 where the sides 1310 , 1311 meet can be H MAX , while the height of the spacer 1300 where the sides 1308 , 1311 meet can be H MID . Embodiments of the spacer 1300 can be wedge-shaped. For example, the top surface 1302 of the spacer 1300 may be inclined at an angle α relative to the bottom surface 1304 . The bottom surface 1304 can also be inclined by an angle β 1 relative to the intersection of the sides 1308 , 1311 . Additionally, the bottom surface 1304 can be inclined at an angle β 2 relative to the intersection of the sides 1310 , 1311 .
The spacer 1300 can include an integral support structure connecting the top surface 1302 and the bottom surface 1304 . The support structure can include a plurality of support ribs. For example, the spacer 1300 includes width ribs 1330 , 1332 extending along the width W of the spacer 1300 between the sides 1306 , 1308 . The spacer 100 can also comprise a length rib 1334 extending along the length L of the spacer 1300 between the sides 1310 , 1311 and the sides 1312 , 1313 . Bottom surfaces of the ribs 1330 , 1332 , 1334 can form a portion of the bottom surface 1304 of the spacer 1300 .
In some aspects, the support structure includes a plurality of nail boxes. For example, the spacer 1300 comprises nail boxes 1350 , 1352 , 1354 , 1355 , 1356 , and 1357 . Some embodiments of the nail boxes 1350 , 1352 , 1354 , 1355 , 1356 , and 1356 comprise a hollow tube extending from the top surface 1302 and the bottom surface 1304 . The nail boxes 1354 , 1355 can be connected to the width rib 1331 via flanges 1360 and 1362 . Other configurations are possible. For example, in some aspects, the spacer 1300 may not comprise width ribs, length ribs, nail boxes, and/or flanges.
In some aspects, the nail box 1354 comprises a recessed area 1351 and the nail box 1355 comprises a recessed area 1353 (not illustrated). The recessed areas 1351 , 1353 can accommodate the head of a nail or other fastener disposed in nail boxes 1354 , 1355 , respectively. It will be understood that other nail boxes of the spacer 1300 can comprise recessed areas, and that the spacer 1300 need not comprise any recessed areas around the nail boxes.
FIGS. 12-15 illustrate this embodiment of a spacer according to the present invention in use on a roof 1468 that has three or more sides. Referring now to FIG. 12 , a spacer 1400 according to one embodiment is positioned between a support beam 1470 and a first roofing panel or board 1475 . The roof 1468 also comprises a second spacer 1400 positioned between the support beam 1470 and a second panel 1482 . The support beam 1470 includes a top surface 1472 . The panels 1475 , 1482 each include a top surface 1476 and a bottom surface 1478 . The support beam 1470 can comprise a portion of the support structure of a roofing system, and the panels 1475 , 1482 can comprise a portion of the outer skin of the roofing system.
A top surface 1402 of the spacers 1400 are adjacent to and contact the bottom surfaces 1478 of the panels 1475 , 1482 , while a bottom surface 1404 of the spacers 1400 are adjacent to and contact the top surface 1472 of the support beam 1470 . Other configurations are possible.
In one embodiment of the present invention, the spacers 1400 are positioned on the support beam 1470 such that a vertical space 1484 separates the panels 1475 , 1482 . In some aspects, each of the adjacent panels on the roof 1468 are separated by a vertical space 1484 . As described above with reference to FIG. 3 , the vertical spaces 1484 can advantageously allow for air to enter the space underneath the roof 1468 and circulate within the space. Advantageously, the vertical spaces 1484 can also allow light to enter the space underneath the roof 1468 .
In some aspects, the top surface 1476 of the panel 1475 and the bottom surface 1478 of the panel 1482 overlap in a region 1486 . This overlap between adjacent panels 1475 , 1482 can advantageously restrict rain and other weather elements from passing through the spaces 1484 and entering the space underneath the roof 1468 .
FIGS. 13-15 illustrate a plurality of panels spaced from the support beam 1470 by the spacers 1400 . The panel 1475 and a panel 1492 are positioned on a first spacer 1400 (not illustrated), and the panel 1482 and a panel 1494 are positioned on a second spacer 1400 (not illustrated). A third spacer 1400 is also positioned on the support beam 1470 , ready to receive panels. As described above, the spacers 1400 allow the panels 1492 , 1494 to be advantageously separated by a vertical space 1484 .
Installation of Roofing Spacers
Embodiments of the roofing spacers described herein can be installed using fasteners such as nails. In one embodiment, a spacer according to the present invention is first positioned on a support beam. Nails are driven into one or more nail boxes of the spacer. The nails may be driven into nail boxes comprising recessed areas, for example. These nails may initially restrict movement of the spacer relative to the support beam until additional nails are driven into the spacer. Next, a panel is positioned over the spacer, and additional nails are driven through the panel into the spacer. In some aspects, the installer is aware of the general location of the nail boxes which remain empty, but is not able to see the precise location of the empty nail boxes through the panel. The installer can estimate the location of the empty nail boxes and aim the nails so that they enter the spacer at or near the empty nail boxes.
It will be understood by those of skill in the art that positioning nails precisely in the nail boxes is not required to install embodiments of spacers described herein. Nails and other fasteners can effectively secure the spacers to support beams, and panels to the spacers, if they are driven into the nail boxes, the ribs, and/or the flanges described herein. It will also be understood that a nail need not be driven into each nail box provided on the spacers in order to secure the spacer to a support beam, or to secure a panel to the spacer.
Materials for a Roofing Spacer
Embodiments of the spacers described herein can be made of any suitable material, including plastic or metal. In one embodiment, spacers according to the present invention are made of polypropylene copolymer. In some aspects, the comonomer of the polypropylene copolymer is ethylene. Polypropylene copolymer is characterized as having high impact resistance strength. Polypropylene copolymer also has slightly increased elongation at break, and is thus more pliable, compared to unmodified polypropylene homopolymer. Typical material properties of polypropylene copolymer are provided in Table 1 below.
TABLE 1
Property
Yield Point
24
MPa
Elongation at Yield
10-12%
Tensile Break
33
MPa
Elongation at Break
650%
Tensile Modulus
1050
MPa
Flexural Modulus
1270
MPa
Flexural Strength
25-26
MPa
Tensile Impact
800
kJ/m2
Spacers described herein need not be made of polypropylene copolymer, and can be made of any suitable material, including but not limited to materials exhibiting material properties similar to that of polypropylene copolymer. Spacers made of polypropylene copolymer can advantageously accept fasteners without shattering or suffering other adverse structural effects which may result when a nail or other fastener is driven into the spacer.
Embodiments of the spacers described herein can be molded from one piece of injection-molded plastic, such that the spacer is monolithic. The spacers described herein can also be manufactured by connecting together separate components, such as the top surface, the bottom surface, the back, and the integral support structure, to form one spacer.
The above-described embodiments have been provided by way of example, and the present invention is not limited to these examples. Multiple variations and modifications to the disclosed embodiments will occur, to the extent not mutually exclusive, to those skilled in the art upon consideration of the foregoing description. Additionally, other combinations, omissions, substitutions and modifications will be apparent to the skilled artisan in view of the disclosure herein. Accordingly, the present invention is not intended to be limited by the disclosed embodiments.
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Devices, methods, and systems are provided herein for spacing an outer skin of a roof from the supporting structure of the roof such that the roof shields against weather elements, admits light, and allows advantageous air circulation. In one embodiment, a wedge-shaped device for spacing panels on a roof includes a bottom surface, a top surface inclined at an angle relative to the bottom surface, and an integral support structure connecting the top surface and the bottom surface, the support structure including a plurality of ribs and a plurality of nail boxes.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. patent application Ser. No. 11/943,329, filed Nov. 20, 2007, now U.S. Pat. No. 7,905,990, which application is fully incorporated herein by reference.
FIELD OF THE INVENTION
The present invent relates to the rapid thermal conversion of wood and/or other biomass into high yields of valuable liquid product, e.g., bio-oil.
BACKGROUND OF THE INVENTION
Biomass has been the primary source of energy over most of human history. During the 1800's and 1900's the proportion of the world's energy sourced from biomass dropped sharply, as the economical development of fossil fuels occurred, and markets for coal and petroleum products took over. Nevertheless, some 15% of the world's energy continues to be sourced from biomass, and in the developing world, the contribution of biomass to the energy supply is close to 38%.
Solid biomass, typically wood and wood residues, is converted to useful products, e.g., fuels or chemicals, by the application of heat. The most common example of thermal conversion is combustion, where air is added and the entire biomass feed material is burned to give hot combustion gases for the production of heat and steam. A second example is gasification, where a small portion of the biomass feedstock is combusted with air in order to convert the rest of the biomass into a combustible fuel gas. The combustible gas, known as producer gas, behaves like natural gas but typically has between 10 and 30% of the energy content of natural gas. A final example of thermal conversion is pyrolysis where the solid biomass is converted to liquid and char, along with a gaseous by-product, essentially in the absence of air.
In a generic sense, pyrolysis is the conversion of biomass to a liquid and/or char by the action of heat, normally without using direct combustion in a conversion unit. A small quantity of combustible gas is also a typical by-product. Historically, pyrolysis was a relatively slow process where the resulting liquid product was a viscous tar and a “pyrolygneous” liquor. Conventional slow pyrolysis has typically taken place at temperatures below 400° C. and at processing times ranging from several seconds to minutes. The processing times can be measured in hours for some slow pyrolysis processes used for charcoal production.
A more modern form of pyrolysis, termed fast pyrolysis, was discovered in the late 1970's when researchers noted that an extremely high yield of a light pourable liquid was possible from biomass. In fact, liquid yields approaching 80% of the weight of the input woody biomass material were possible if the pyrolysis temperatures were moderately raised and the conversion was allowed to take place over a very short time period, typically less than 5 seconds.
The homogeneous liquid product from fast pyrolysis, which has the appearance of espresso coffee, has since become known as bio-oil. Bio-oil is suitable as a fuel for clean, controlled combustion in boilers, and for use in diesel and stationary turbines. This is in stark contrast to slow pyrolysis, which produces a thick, low quality, two-phase tar-aqueous mixture in very low yields.
In practice, the fast pyrolysis of solid biomass causes the major part of its solid organic material to be instantaneously transformed into a vapor phase. This vapor phase contains both non-condensable gases (including methane, hydrogen, carbon monoxide, carbon dioxide and olefins) and condensable vapors. It is the condensable vapours that constitute the final liquid bio-oil product and the yield and value of this bio-oil product is a strong function of the method and efficiency of the downstream capture and recovery system. The condensable vapors produced during fast pyrolysis continue to react in the vapour phase, and therefore must be quickly cooled or “quenched” in the downstream process before they can deteriorate into lower value liquid and gaseous products. As fast pyrolysis equipment is scaled up in commercial operations, particular attention must be given to the strategy and means of rapid cooling, quenching and recovery of the liquid bio-oil product.
SUMMARY
The present invention provides improved rapid thermal conversion processes of biomass by effecting the efficient recovery of high yields of valuable liquid product (e.g., bio-oil) from the vapor phase, on a large scale production.
In an embodiment, biomass material, e.g., wood, is feed to a conversion system where the biomass material is mixed with an upward stream of hot heat carriers, e.g., sand, in a substantially oxygen-free environment in a thermal conversion temperature range between 350 and 600° C. The hot heat carriers contact the biomass material thermally converting the biomass into a hot vapor stream, which is cooled, condensed, and recovered downstream as a liquid product. In a preferred embodiment, the thermal conversion occurs at a temperature of around 500° C. with a resident time of less than 5 seconds, and more preferably less than 2 seconds.
The hot vapor stream is directed to a condensing chamber, or a multiple of condensing chambers, where the hot vapor stream is rapidly cooled from a conversion temperature of approximately 350° C. to 600° C. to a temperature of less than 100° C. in less than 1 s, more preferably to a temperature of less than 50° C. in less than 100 ms, and most preferably to a temperature of less than 50° C. in less than 20 ms. In a preferred embodiment, the upward flowing vapor stream is cooled by rapidly quenching the vapor stream with a downward flow of quench media. This rapid and intimate cooling or quenching by a downward flow of quench media condenses the vapor stream into liquid product. In a preferred embodiment, a portion of the condensed liquid product is drawn out of the condensing chamber, or chambers, cooled and circulated back to the condensing chamber, or chambers, to provide the quench media. The liquid product used for the quench media may be cooled to a temperature of between 30° C. and 50° C. before being circulated back to the condensing chamber. Preferably, the quench media is poured down at a rate of at least 10 gpm/sq. ft (gallon per minute/sq. ft) of the cross-sectional area of the condensing camber, and more preferably at a rate of at least 50 to 100 gpm/sq. ft. The liquid product in the chamber is collected as a valuable liquid product, e.g., bio-oil, that can be used, e.g., for fuel and/or other commercial uses. The processes of the invention are able to produce high yields of valuable liquid product, e.g., approximately 75% or more of the input biomass material.
In an embodiment, a second condensing chamber located downstream of the first condensing chamber is used to condense vapor that evades condensation in the first condensing chamber to increase the yield of liquid product. The second condensing chamber may use the same or different quench media as the first condensing chamber.
In an embodiment, a demister and filter are associated with the first and/or second condensing chambers to remove fine particles from the gas stream exiting the condensing cambers and collect additional liquid product from the gas stream.
Preferably, the conversion and collection process is carried at or near atmospheric pressure, which makes biomass feeding, conversion, and the collection of the liquid product easier and safer. This also allows the biomass to be continuously feed to the conversion system at a high rate facilitating large scale industrial production of the liquid product.
The above and other advantages of embodiments of this invention will be apparent from the following more detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a diagram of a thermal conversion and liquid product collection system according to an exemplary embodiment of the present invention.
FIG. 2 shows a feed system for feeding biomass feedstock to the thermal conversion system according to an exemplary embodiment of the present invention.
FIG. 3 shows a reheater for reheating heat carriers according to an embodiment of the present invention.
FIG. 4 is a table showing results for exemplary thermal conversion processes according to embodiments of the present invention.
DETAILED DESCRIPTION
FIG. 1 shows a rapid thermal conversion system 10 for converting biomass, e.g., wood, into high yields of liquid product according to an exemplary embodiment of the present invention.
Feed System
The feed system 15 is used to provide a regulated flow of solid biomass feedstock to the conversion system 10 . Preferably, the biomass feedstock is a dry wood feedstock, which may be in the form of sawdust, but liquid and vapour-phase (gas-phase) biomass materials can be effectively processed in the rapid thermal conversion system using an alternative liquid or vapour-phase feed system. Biomass feedstock materials that may be used include, but are not limited to, hardwood, softwood, bark, agricultural and silvicultural residues, and other biomass carbonaceous feedstocks. Embodiments of the invention can also be applied to the conversion of other carbonaceous feedstocks including, but not limited to, plastics, polymers, hydrocarbons, petroleum, coal, and refinery feedstocks. Since the conversion system operates at slightly above atmospheric pressure (i.e., sufficient pressure to overcome the back pressure of the down stream equipment), the feed system 15 should provide material to the conversion system 10 under slight pressure (1.2 atmospheres) while at the same time accepting feedstock material from, e.g., a wood storage silos, which is at atmospheric pressure. To achieve a continuous supply of feedstock in this manner a lock-hopper system is utilized, which is shown in greater detail in FIG. 2 .
The feed system 10 comprises a feedstock surge bin 17 , a feed bin 20 , and a transfer valve 22 , e.g., knife gate valve, between the surge bin 17 and feed bin 20 . The valve 22 provides isolation of the surge bin 17 from the feed bin 20 , and preferably comprises an elastomer seat to ensure a gas tight seal. The valve 22 allows filling of the surge bin 17 with feedstock under atmospheric conditions while maintaining a seal in the feed bin 20 so that the feed bin 20 can operate at above atmospheric pressure.
The feedstock surge bin 17 is preferably a cylindrical vessel constructed of carbon steel and has a capacity that is sufficient to hold enough feedstock, e.g., for approximately 30 minutes of feedstock transfer before refilling. The surge bin 17 is equipped with a bottom-out feed system and internal bridge-breaking device used to dislodge held-up biomass material. Examples of bridge breaking devices include a sweep-arm with or without finger projections, vibration devices, swing chains, and the like. The rate of feedstock discharge from the surge bin 17 may be fixed and a full transfer cycle completed within approximately 10 minutes. Three level sensors (high level switch high, low level switch low, and low-low level switch) may be used to activate feedstock transfer. In addition, continuous monitoring of the feedstock material level in the surge bin 17 may be achieved with a level transmitter. When the level of material in the surge bin 17 drops to activate the low level switch, feedstock material will automatically be transferred from the feedstock storage system (not shown) to the surge bin 17 . The high level switch is used to indicate when the surge bin is full and the material transfer from the feedstock storage system is terminated. The low-low switch is a back-up switch to indicate that the bin is empty when the low level switch is not triggered. This may occur, e.g., when material holds up on the low level switch giving a false reading. The valve 22 is closed when the surge bin is being filled.
When the level in the feed bin 20 reaches the lower level switch, feedstock material is automatically transferred from the surge bin 17 to the feed bin 20 . Prior to opening the valve 22 , the pressure of the surge bin 17 is equalized with the feed bin 20 . The feedstock material can be transferred from the surge bin 17 to the feed bin 20 by direct transfer when the surge bin 17 is located directly above the feed bin 20 and the valve 22 is opened. Alternatively, if the bins are off-set, then an auger or screw feeder system (not shown) can be used to transfer material from the surge bin 17 to the feed bin 20 . The auger or screw can be horizontal or inclined depending on the relative orientation of the two bins. The feed bin 17 is preferably constructed of carbon steel and is equipped with a volumetric bottom-out feeder. The volumetric feeder provides a metered flow of material to a constant speed conversion inlet screw conveyor 35 , which transfers the material to the conversion system 10 . The operator can adjust the desired flow of material by adjusting the speed of the screw conveyor 35 . To provide feedstock conditioning, an internal bridge-breaking system is incorporated.
The constant speed screw conveyor 35 is constructed of stainless steel and is provided with high temperature seals and bearings. The conveyor 35 may operate at a constant speed and is capable of discharging material into the conversion system 10 at a higher rate than is being provided by the volumetric feeder. This ensures a homogeneous, dispersed flow of material. For safety, the outlet of the screw 35 is fitted with an emergency isolation knife valve and water quench system.
Thermal Conversion System
The thermal conversion system 10 includes a reactor 30 that mixes the feedstock with an upward flowing stream of hot heat carriers, e.g., sand, in a mixing zone. The reactor is essentially oxygen free. The feedstock enters the reactor 30 just below the mixing zone and is contacted by the upward flowing stream of hot heat carriers (sand) and their transport fluid (recycle gas). The result is thorough and rapid mixing and conductive heat transfer (including ablation) from the heat carriers to the feedstock. The hot heat carriers instantly flash the feedstock into a hot vapor, which is cooled, condensed, and recovered downstream as a liquid product.
Thermal conversion of the feedstock is initiated in the mixing zone under moderate temperatures, e.g., approximately 500° C. (approximately 930° F.) and continues through to the separation system 40 located downstream of the reactor 30 . The resident time in the reactor is preferably less than 5 seconds, and more preferably less than 2 seconds. The solid heat carriers along with by-product char are removed from the product vapor stream in the separation system 40 . Preferably, the separation system is fitted with high-abrasion resistant liner to minimize the likelihood of premature failure. The product vapor stream passing through the separation system 40 is directed to the downstream liquid product recovery system 50 .
In the embodiment shown in FIG. 1 , the separation system 40 comprises two cyclonic separators 43 and 45 . The first cyclonic separator 43 separates the solid heat carriers and by-product char from the product stream. The solids that have been removed in the first separator 43 are directed to a reheater unit 47 . The second separator 45 removes char that is not removed in the first separator 43 . The reheater unit 47 is shown in greater detail in FIG. 3 .
In the reheater unit 47 , the by-product char is converted by the addition of air to heat and combustion gases. Typically, there is more than sufficient heat generated by the combustion of by-product char and gas to satisfy the heat requirements of the thermal conversion process (external fuels, such as natural gas, are rarely used and typically for system start-up alone). The excess heat from the reheater can be productively used for other purposes, including biomass drying, steam generation, space heating, power generation, etc. The heat generated in the reheater elevates the temperature of the solid heat carriers, which can then be transferred to the feedstock material in the reactor 30 to achieve the necessary reaction temperatures.
Liquid Product Collection System
The hot vapor product stream from the solids separation system 40 is directed via an insulated duct to a primary collection column or condensing chamber 50 . Preferably, the hot vapor stream is brought from a conversion temperature of approximately 350° C. to 600° C., to less than 100° C. in less than 1 s. More preferably, the hot vapor stream is reduced to less than 50° C. in less than 0.1 s (100 ms), and most preferably to a temperature of less than 50° C. in less than 20 ms. The primary collection column 50 is equipped with a liquid distributor 53 located in the upper portion of the column 50 . Cooled liquid product or other appropriate quench media (e.g., water, diesel, other petroleum based liquid, polysorbate, etc) is circulated through the distributor 53 and allowed to “rain” down on the incoming vapor stream. Various types of distributor systems can be employed. Examples include, but are not limited to, vane, pipe, chimney, finger distributor, spray head, nozzle design, trays, packing, etc. Preferably, at least 10 gpm/sq. ft (gallons per minute/sq. ft) of column cross-sectional diameter of quench liquid is circulated through the collection column. More preferably, at least 50 to 100 gpm/sq. ft of column cross-sectional diameter of quench liquid is circulated through the collection column. The dense stream of liquid raining down the column not only serves to immediately cool and quench the incoming vapor but also provides nucleation sites for the collection of the liquid product. Typically, the hot vapor enters the collection column 50 just above the normal operating level of the collected liquid in the column 50 . The vapor not collected in the primary collection column 50 along with the non-condensable gas exit the column 50 through a top exit port 55 . This mode of operation is counter-current. In another mode of operation in which it is desired to minimize the length of the hot vapor piping the hot vapor enters through the upper portion of the column 50 and the vapor not collected in the column 50 along with the non-condensable gas exit through a port situated in the lower portion of the column (just above the normal liquid level). This mode of operation is co-current. The column 50 may be equipped with a demister in the gas exit section of the column to reduce the carryover of liquid droplets into the second collection column 60 .
Condensed liquid that has associated with the down flowing atomized quench stream accumulates in the lower portion of the column 50 . In addition, heavy condensed droplets fall to the lower portion of the column 50 due to gravitational sedimentation. Level transmitters in the column 50 are used to monitor and maintain the desired liquid levels. In an embodiment, a portion of the liquid product is drawn out from the column 50 and pumped by a condenser pump 57 through a heat exchanger 58 to cool the liquid product to, e.g., 30 to 50° C. The cooling medium for the heat exchanger 58 can be water. Other cooling means may be employed including a glycol system, an air cooler, or the like. The cooled liquid product is circulated back to the column distribution system 53 to provide the quench media for the incoming vapor stream.
The liquid product in the collection column is pumped out to product storage tanks (not shown) to maintain the desired liquid level. The collected liquid product provides a valuable liquid product, bio-oil, that can be used, e.g., for fuel and/or other commercial uses.
The vapor is rapidly quenched because the vapor and liquid product are thermally labile (chemically react at higher temperatures). By using a high liquid recirculation/quench rate, the incoming vapor is rapidly quenched, which avoids undesirable chemical reactions such as polymerization that occur at higher temperatures. Further, the high recirculation rate of the liquid product used for the quench media prevents the quench media from reaching undesirably high temperatures.
The vapor not collected in the primary collection column 50 or vessel is directed to a secondary collection column 60 (secondary condensing column). Again as was the case for the primary condensing column 50 the collected product liquid is used as a quench media via an overhead distribution system 53 . Preferably, at least 10 gpm/sq. ft of column cross-sectional diameter of liquid is circulated through the column 60 . More preferably, at least 50 to 100 gpm/sq. ft of column cross-sectional diameter of quench liquid is circulated through the column 60 . The column 60 may be equipped with a demister in the gas exit section of the column 60 to reduce the carryover of liquid droplets, mist or aerosols into the downstream demister or filtering systems. The cross-sectional diameter of this column 60 may be the same as the primary collection column 50 . However, it is typically smaller in diameter since greater superficial gas velocities will facilitate the removal of the fine droplets or aerosols in the demister section of the column 60 .
Mist, aerosols and non-condensable gas that exit the secondary collection column 60 are directed to a separate demister system 70 . If the secondary collection column 60 is equipped with an internal demister unit, then the downstream separate demister may not be required. The demister system 70 preferably removes mist droplets that are greater than 3 microns. These droplets tend to be captured in the demister by inertial impaction. The particles, which are traveling in the gas stream, are unable to abruptly change direction along with the gas as the flow goes through the demisting system 70 due to their weight. As a result, they impact the fibers of the demister and are subsequently captured. Mist particles that come in contact with the demister fibers adhere by weak Van Der Waals forces. The accumulating impacting mist droplets tend to join together to form larger single droplets that finally fall to the lower portion of the demister vessel due to gravitational sedimentation.
The demister system 70 may comprise a series of mist eliminator units. The first unit is a vane mist eliminator which can remove about 99% of the mist as low as 10 microns. Next is a stainless steel wire mesh pad having a density of about 5 lbs/ft 3 and a wire diameter of 0.011 inches (surface area of 45 ft 2 /ft 3 , and 99.0% voids). Other materials may be used besides steel including glass, alloy 20, Teflon, polypropylene, or the like. This is followed by a 9 lb/ft 3 stainless steel wire mesh pad, again 0.011 inch diameter (surface area of 85 ft 2 /ft 3 , and 98.0% voids). The final mist eliminator unit is a co-knit style comprising a metal wire construction with fiberglass. The pad is 9 lb/ft 3 with a wire diameter of 0.00036 inches (surface area of 3725 ft 2 /ft 3 , and 99.0% voids).
Fine aerosols (i.e., less than approximately 3 microns), condensed particles of greater than 3 microns that evaded the demister system 70 , and non-condensable gas from either the secondary condensing column 60 or the demister system 70 pass to a final filtering system 80 . The filter system 80 may comprise two fiber beds 80 A and 80 B set up in parallel, as shown in FIG. 1 . Again, as was the case with the demister system 70 , particles larger than about 3 microns are captured by inertial impaction. Condensed particles between 1 and 3 microns tend to be captured through interception in which the particles follow the non-condensable gas stream line that comes within about one particle radius of the surface of a fiber. Particles of less than 1 micron are captured through diffusion or Brownian movement in which the particles have a tendency to attach themselves to the fibers of the filter 80 due to their random motion. Again, captured particles tend to join together to form larger liquid droplets. However, the pressure drop across the filter 80 may exceed predetermined limits before a sufficient quantity of material has drained to the lower section of the filter vessel. In addition, re-entrainment of collected material can occur as the localized loading of liquid increases the effective open cross-sectional area of the filter decreases thereby increasing the flow of gas through the remaining open areas. This increase flow of gas leads to increased velocities that can lead to higher than desired pressure drops and possibly re-entrainment, and loss of captured liquid. Therefore, the filtering system 80 can consist of more than one filter unit which can be set up in parallel or in series as required. Typically two filter units 80 A and 80 B are employed in parallel in which one filter unit is on-line at any one time. A filter unit may remain on-line for a period of about 8 to 24 hours (typically 12 hours). When the filter unit is switched off-line it is allowed to drain. The pressure drop across the filter unit can also dictate the period of time that the unit is allowed to remain on-line. Pressure drops that exceed predetermined limits (typically 100 inches of water column) can lead to failures of the filter elements (i.e., tear holes can develop in the fabric) of the filter unit.
Since the collected mists and aerosol liquid can tend to be relatively viscous at ambient conditions a reheat exchanger 90 can be employed between the secondary condenser column 60 and the demister 70 and fiber bed filters 80 A and 80 B. Alternatively, if the demister is incorporated in the secondary condenser column 60 , the reheat exchanger will be installed upstream of the fiber bed filters 80 A and 80 B only. This reheat exchanger 90 is used to slightly elevate the temperature of the vapor stream (up to about 60-65° C.) and enable a sufficient viscosity reduction of the captured liquids in the downstream systems 70 and 80 to allow adequate drainage.
The gas filtered through the filter system 80 is recycled back to the reactor 30 by reactor blower 95 . The recycled gas provides the transport fluid for the upward flow of hot carriers in the mixing zone of the reactor 30 .
Results for exemplary thermal conversion processes according to embodiments of the present invention will now be discussed. In these examples, the primary and secondary collection columns each had a diameter of approximately 4 feet. The feed rate of biomass material into the conversion system varied between approximately 2650 to 3400 lb/hr. The temperature of the incoming vapor was approximately 500° C. with a flow rate of approximately 1100 standard cubic feet per minute (scfm). In these examples, a portion of the liquid product in each collection column was cooled and circulated back to the collection column to provide the quench media. Table 1 below shows quench temperatures and recirculation rates for nine exemplary process parameters. The quench temperature is the temperature of the cooled liquid product prior to injection back to the collection column, and the recirculation rate is the flow rate of the liquid product at the top of the collection column.
TABLE 1
Quench Temperatures and Recirculation Rates
BIO-OIL
BIO-OIL
QUENCH
RECIRCULATION
EXAMPLE
TEMPERATURE (° C.)
RATE (GPM)
1
36
750
2
30
760
3
41
715
4
36
670
5
30
675
6
41
675
7
36
625
8
30
625
9
41
625
Results for the nine examples are shows in Table 2 in FIG. 4 . Each exemplary process was conducted over a period of approximately 12 hours. Table 2 shows the percentage distribution of bio-oil collected in the primary and secondary collection columns or condensers, in which the collection in the secondary collection column included bio-oil collection from the demister and fiber bed filters. Table 2 also shows properties of the bio-oil collected from the primary and secondary collection columns.
Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that the disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read this disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the spirit and scope of the invention.
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An improved rapid thermal conversion process for efficiently converting wood, other biomass materials, and other carbonaceous feedstock (including hydrocarbons) into high yields of valuable liquid product, e.g., bio-oil, on a large scale production, is disclosed. In the process, biomass material, e.g., wood, is fed to a conversion system where the biomass material is mixed with an upward stream of hot heat carriers, e.g., sand, that thermally convert the biomass into a hot vapor stream. The hot vapor stream is rapidly quenched with quench media in one or more condensing chambers located downstream of the conversion system. The rapid quenching condenses the vapor stream into liquid product, which is collected from the condensing chambers as a valuable liquid product.
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This application is a continuation of U.S. patent application Ser. No. 14/672,470, filed Mar. 30, 2015, which claims priority to U.S. Provisional Patent Application Ser. No. 61/974,254 filed on Apr. 2, 2014 in the name of Russell W. White and Stanley M. Dufek entitled ROPE CLEATING SYSTEM, the content of which is hereby incorporated by reference.
TECHNICAL FIELD
The following disclosure relates to rope cleats, and more particularly to a rope cleating system.
BACKGROUND
Generally speaking, rope cleats facilitate the securing of a rope to or around an object. Often, a cleat is attached to a dock, and a person ties a rope that is connected to a boat around the cleat. One example is a double horn cleat to which a person typically ties a cleat hitch knot. However, many boaters do not know how to tie proper knots like the cleat hitch knot.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an exploded view of a rope cleating system that incorporates teachings of the present disclosure for improved performance.
FIG. 2 depicts a photographic style image that depicts use of a rope cleating system that incorporates teachings of the present disclosure.
FIG. 3A illustrates a traditional double horned cleat with a rope secured using a cleat hitch knot.
FIG. 3B illustrates a traditional double horned cleat with a rope secured using an arbitrary knot that will not remain secure.
DETAILED DESCRIPTION
As mentioned above, a rope cleat can be used to facilitate the securing of a rope to or around an object. One type of cleat, the double horned cleat, can often be found on boat docks. In many cases, the cleat is bolted or screwed to a wooden dock and made available to docking boats. In such a circumstance, the docking boat may have a rope tied to some portion of the boat. The end of the rope that is not tied to the boat may be used to tether the boat to the dock by wrapping the rope around the double horned cleat. As shown in FIGS. 3A and 3B , there can be significant differences in the type of knot used to tie off to the cleat. FIG. 3A illustrates a traditional double horned cleat with a rope secured using a cleat hitch knot. The knot depicted in FIG. 3A is an effective knot and should keep a tethered boat securely connected to the dock. FIG. 3B illustrates a traditional double horned cleat with a rope secured using an arbitrary knot that will not remain secure.
Many boaters lack the knot tying expertise necessary to safely secure a boat to an available double horned cleat. The cleating systems depicted in FIGS. 1 and 2 , in addition to other potential benefits, could help these boaters to safely secure their boats to available docks. As mentioned above, FIG. 1 illustrates an exploded view of a rope cleating system 100 that incorporates teachings of the present disclosure for improved performance. As shown, system 100 includes a cleating sleeve 102 , an anchoring sleeve 104 , and a floating shell 106 . Though system 100 is depicted in an exploded manner, one skilled in the art will recognize how system 100 may be connected into a unit. Moreover, one skilled in the art will recognize that the three-piece system could also be manufactured as a one-piece or a two-piece system. Similarly, a designer may elect to utilize a system with more than three pieces.
As shown, cleating sleeve 102 defines a generally elliptical opening 108 through which a rope may be doubled back upon itself. Cleating sleeve 102 also includes a member 109 and an end cap 110 that defines a shoulder 112 that may serve to help keep floating shell 106 in position when cleating sleeve 102 and anchoring sleeve 104 are connected. Cleating sleeve also includes a cleat opening 114 that defines three cleating locations indicated generally at 116 . In practice, a rope may pass through elliptical opening 108 (along the bottom of the opening), around anchoring sleeve 104 (as defined more fully below) and back through elliptical opening 108 (this time above the earlier passed rope). The tag end of the rope routed in such a way may then be pulled into cleat opening 114 and removably locked in place.
Cleating sleeve 102 also includes locking port 116 , which may interact with locking node 118 to help secure cleating sleeve 102 to anchoring sleeve 104 . In some instances, locking port 116 and locking node 118 may releasably connect sleeves 102 and 104 . For example, a designer may offer system 100 as a kit with more than one anchoring sleeves like sleeve 104 . Each of the sleeves included in such a kit may be sized for use with different diameters of rope. If a boater is using ⅜ inch rope, the boater may use an anchoring sleeve designed for ⅜ to ½ inch rope (for example). If the boater is using ⅝ inch rope, the boater may upsize to an anchoring sleeve designed for ropes larger than ½ inch.
As shown, anchoring sleeve 104 includes a dual port system 120 , which may allow for a separation of the rope as it passes into and out of anchoring sleeve 104 . Dual port system 120 (as depicted) extends through member 121 and includes deflection slits 122 , which facilitate the sliding of anchoring sleeve 104 or at least a portion of sleeve 104 into cleating sleeve 102 . In addition, deflection slits 122 may create a spring force that helps lock depicted locking node 118 into locking port 116 . Anchoring sleeve 104 may also include an end cap 124 that acts in a manner similar to end cap 110 .
As shown, dual port system 120 may include two holes that remain independent from one another and are formed all the way through anchoring sleeve 104 . Such a design may keep a rope passed through the bottom hole and then routed back through the top hole from being “pulled through” and accidently removed from system 100 . As shown, the holes of anchoring sleeve 104 may be specifically designed for a given diameter of rope. The holes may also be designed with some “slop” to allow for some flexibility in the diameter of rope used. For example, the holes may allow for the sliding through of a rope having a ⅜ inch diameter, a ½ inch diameter, or both.
System 100 , as depicted, also includes floating shell 106 , which surrounds cleating sleeve 102 and anchoring sleeve 104 when system 100 is snapped together. Though floating shell 106 , as depicted, is intended to provide buoyancy and to help system 100 float when in use, a given designer may choose to create floating shell 106 from a material that does not float. As shown, floating shell 106 is intended to float and to provide some give or impact resistance. As such, floating shell 106 may be formed from several different materials. For example, floating shell 106 may be formed from neoprene, sponge, foam, rubber, plastic, some other lightweight material, and/or a combination of materials. Similarly, cleating sleeve 102 and anchoring sleeve 104 may be formed from the same or different materials. In one example version of system 100 , cleating sleeve 102 and anchoring sleeve 104 may be formed from an extruded plastic material while floating shell 106 may be formed from a scuba foam, a fabric, a foam, a neoprene, or other high buoyancy material that facilitates screen printing on its exterior surface.
As depicted, floating shell 106 is sized to fit snugly around cleating sleeve 102 and anchoring sleeve 104 and to be held in place by end caps 110 and 124 when cleating sleeve 102 and anchoring sleeve 104 are connected to one another. In addition, floating shell 106 includes cut out 126 , which may help a user to pull the tag end of a rope into cleat opening 114 without undue interference from floating shell 106 . As shown, the generally elliptical cross section of cleating sleeve 102 , anchoring sleeve 104 , and the hole 128 formed through floating shell 106 may help to keep cut out 126 in position relative to cleat opening 114 . In addition, a designer may elect to include a printable location 130 on shell 106 to facilitate the inclusion of marketing, branding, and/or contact information, some or all of which may be printed and/or reproduced on shell 106 .
As indicated above, system 100 incorporates teachings of the present disclosure and represents one way a designer may choose to implement some teachings. Many things could be altered if a designer so chooses without departing from the present teachings. As mentioned above, the number of component parts within system 100 may be changed. Similarly, different materials may be chosen. Components of a system like system 100 may include, for example, one or more of a plastic material, a rubber material, a spandex material, a leather material, a neoprene material, a metal material, a wooden material, a woven material, and/or some other material that is suitable for performing the objectives of system 100 .
As indicated above, FIG. 2 depicts a photographic style image of a rope cleating solution 200 that incorporates teachings of the present disclosure. As shown, a system 202 , which may be like system 100 , is shown in an assembled state. In addition, a rope 204 is shown as passing through system 202 around double horned cleat 206 and back through system 202 . Rope 204 , as depicted, has been seated into a cleating mechanism 208 , which may be similar to cleat opening 114 . The tag end 210 of rope 204 is shown as resting on a wooden dock 212 to which double horned cleat 206 is attached.
System 202 also depicts an outer shell 214 , which may be similar to floating shell 106 . As shown, outer shell 214 presents a printable surface 216 onto which the words “SeaRay” and “www.searay.com” are printed. The printing technique may include, for example, silk screen printing, embossing, branding, labeling, stamping, embroidering, etc., and/or some combination of these or other techniques. As shown, printable surface 216 may made from a material and offered in a size and shape that facilitates the inclusion of branding, marketing, and/or contact information, among other things.
In one offering, a system, like system 202 , may work with various standard rope diameters, may be made of some combination of soft, durable, and/or floating materials, and may provide a surface to add marketing and contact information. Such a system may, for example, help boaters who tie knots like the one depicted in FIG. 3B to safely and securely tether their boats to docks with double horned cleats.
A system incorporating teachings of the present disclosure may replace, add, or delete many of the above-described features and components without departing from the scope of the disclosure. One skilled in the art will recognize that the many of the above-described components could be combined or broken out into other combinations.
Although the present invention has been described in detail, it should be understood that various changes, substitutions and alterations to the devices, methods, and other aspects and techniques of the present invention can be made without departing from the spirit and scope of the invention as defined by the appended claims.
While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
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A system for rope cleating is disclosed. A system incorporating teachings of the present disclosure may include a cleating component, an anchoring component, and an exterior shell. In practice, the system may facilitate connecting a boat to a dock even if the boater is unfamiliar with proper nautical knots.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an integrated unit performing a plurality of functions related to air treatment in pneumatic systems.
2. State of the Prior Art
Practically all pneumatic systems using compressed air for actuation functions of every type start with a unit for treatment of the compressed air. In fact, the air before being admitted into the distributors and actuators is required to be regulated and filtered. Therefore, these units are applied to all working machines, such as assembling machines, machine tools, packaging machines, etc.; in the compressed-air distribution systems, in the car field, in particular in equipped lorries, in the industry field, etc.
All known units consist of individual elements, each having a specific function, that are then assembled in series with each other. The most traditional combination of elements used in automation may comprise a manual on-off valve at the inlet, a filter, a pressure regulator, an electric on-off valve, a pressure switch, several intakes, etc.
The elements can be someway of the modular type so as to have attachments and sizes compatible with each other in the same series, but in any case they are always elements that must be assembled one after the other.
There are many limits and defects in the units made with known elements. It is to be mentioned the big sizes, in particular with a high extension in the formation direction of the series; the very bad ergonomics due to the fact that the functions of interest of the user or the maintenance man are distributed in an incoherent manner on the unit, some on the upper side (the pressure regulating hand grips, for example), some on the front (manometer, etc.), some on the lower side (filter cup), so that there are not only positioning difficulties but also a poor understanding of the functions performed by each element and of the point which must be acted upon for regulations; the difficulties for servicing interventions, such as replacement of the filter cartridge; the very bad overall aesthetic appearance that is no longer suitable for the modern machines for which the units are designed.
In addition, some functional problems are still unresolved, so that the reliability of the system as a whole is impaired due to leakages, jamming, etc.
For example, in known filter modules or elements the servicing interventions, such as replacement of the filter cartridge, are difficult and often uncomfortable, above all when the unit is positioned in regions of the machine utilizing it that are hardly accessible. In particular, in order to receive the condensate at the filter base, the cartridge is always disposed vertically in a cup under the air inlet, with the air flow that is radially directed from the cartridge outside to the inside. Such an arrangement creates problems in terms of vertical bulkiness that can be hardly resolved, so that uncomfortable operations are required even if the filter cup is only to be unscrewed.
In addition, the automatic systems for condensate discharge are subjected to jamming in the presence of solid particles suspended in the air and therefore they are often refused by the user.
It is a general aim of the present invention to obviate the above mentioned drawbacks by providing an innovative integrated unit enabling supply of the different facilities that are necessary at the inlet of pneumatic systems and, among other things, possessing features of small bulkiness, high reliability, practical and quick use and ready maintenance.
It is a further aim of the present invention to provide said unit with a filtering device equipped with an efficient and easily accessible filter, above all for the operations concerning maintenance and replacement of the cartridge and that, if also equipped with a device for condensate discharge, does not suffer for jamming due to the presence of solid particles entrained into the device by the air flow.
A still further aim of the present invention is to provide the unit with a regulation device for progressive starting that is of reduced bulkiness and is capable of offering a satisfactory progressive starting irrespective of the conditions of the circuit downstream thereof.
SUMMARY OF THE INVENTION
In view of the above aims, in accordance with the invention, an integrated unit for air treatment in pneumatic systems has been devised, which comprises a box-shaped body provided with an inlet for the air to be treated and with at least one outlet for the treated air and containing devices for treatment and regulation of the air flow between the inlet and outlet, said devices comprising at least one filter device, one pressure regulator and one progressive-starting device.
BRIEF DESCRIPTION OF THE DRAWINGS
For better explaining the innovative principles of the present invention and the advantages it offers over the known art, a possible embodiment applying said principles will be described hereinafter by way of example, with the aid of the accompanying drawings. In the drawings:
FIG. 1 is a diagrammatic front view of a unit in accordance with the invention;
FIG. 2 is a diagrammatic view partly in section of part of the inside of the unit seen in FIG. 1 ;
FIG. 3 is a diagrammatic view of the unit taken along line III-III in FIG. 2 ;
FIG. 4 is a diagrammatic view in section of a detail of the unit where also part of the block diagram of the unit circuit is represented;
FIG. 5 is a diagrammatic view of the unit taken along line V-V in FIG. 2 .
DETAILED DESCRIPTION OF THE INVENTION
With reference to the drawings, shown in FIG. 1 is an integrated unit generally denoted at 210 , implemented in accordance with the principles of the invention. Unit 210 has a generally parallelepiped or box-shaped conformation with a body 10 on the external surface of which connectors, commands, indicators, etc. appear. In particular, a main inlet connector 11 and an opposite main outlet connector 12 are present. Advantageously, also an auxiliary outlet 13 which is filtered but not regulated and two auxiliary outlets 14 , 15 in parallel to the main outlet 12 but with a connector of different diameter (¼″, for example) can be present. All connectors are disposed on side faces.
The indicators and commands are disposed on the front panel. As clarified in the following, they comprise, among other things, a regulator 224 for regulation of the progressive-starting function and a manual shutoff and air-discharge valve 228 . Advantageously, there may be also the presence of a pilot pressure regulator 227 , an outlet pressure switch 17 , a manometer 16 and LED signallers visually indicating the activation state of the pressure switch and the state of a possible inner solenoid valve (denoted at 229 in FIG. 4 ). The connections of the manometer and pressure switch at the exit of the device are well visible in the section in FIG. 5 as well.
As further described in the following, unit 210 also comprises a filter device 114 whose plug 120 for access to the cartridge is disposed with a horizontal axis and appears on the front panel as well, and a condensate discharging device 115 with a lower outlet 127 for the water and projecting from the lower side of the unit.
Also provided may be an electric side connector 18 reproducing the electric signals of the pressure switch and LED indicators and said connector 18 is powered and receives the activation signal from the solenoid valve.
Shown in FIG. 2 is part of the whole unit. In particular, clearly shown is the main inlet connector 11 , the device portion 110 concerning filtering and condensate discharge, with the filter unit 114 and the condensate collection and discharge assembly 115 , a piloted valve 212 for pressure regulation, a piloting unit with progressive starting 215 .
Diagrammatically shown in FIG. 3 is a section taken along line III-III in FIG. 2 of the portion 110 of unit 210 carrying out air filtering and condensate discharge, in accordance with a preferred solution of the invention.
With reference to FIG. 3 , the filter and condensate discharge region comprises a body 111 (advantageously of one piece with the body of the remainder of the unit) provided with an inlet 112 for the air to be filtered coming from the main inlet connector 11 , and an outlet 113 for the filtered air which is directed to the remainder of the unit and towards the main outlet connector 12 . Housed in body 111 is the filter unit 114 and the condensate collection and discharge assembly 115 .
The filter unit 114 is advantageously extended along a horizontal axis 116 while the condensate assembly 115 is disposed under the filter unit and is extended along a vertical axis 117 . The condensate assembly is disposed downstream of the filter unit and the air flow radially passes through the filter from the inside to the outside.
In particular, the filter unit is provided with a suitable cylindrical filtering cartridge 118 , received in a suitable seat 119 sealingly closed by the threaded plug 120 , also of horizontal axis 116 .
Advantageously, the air inlet 112 communicates with the inside of cartridge 118 through an on-off valve 121 the closure member 122 of which is pushed and closed against an abutment 123 by the action of a spring 124 . Axially present internally of the plug 120 is a rod 125 that, when the plug 120 is correctly screwed down in place, keeps the valve open against the action of spring 124 .
The condensate assembly 115 comprises a cup 126 for collection of the condensate entrained through the filter. The cup has a lower exhaust outlet 127 that can be operated either manually (with a screw threaded plug or a valve, for example) or advantageously in an automatic manner by a known float valve 128 opening when the liquid level in the cup exceeds a predetermined threshold.
Present on the cup 126 top is a system consisting of inclined lamellae 129 such disposed that they are licked by the air flow directed towards the outlet 113 so as to separate the condensate from the flow itself and cause dripping of the condensate into the underlying cup.
The horizontal arrangement of the filter with front extraction makes the device both compact and of easy placement and quick maintenance. In addition, the air flow passing through the filter cartridge from the inside to the outside causes the intercepted dirt to remain internally of the cartridge when the latter is removed from its seat, which will facilitate replacement of the cartridge and make it quicker. Separation of the condensate after filtering also prevents particles of dirt from reaching the condensate assembly and stopping or clogging the exhaust outlet. This ensures a high reliability of the possible advantageous self-discharge device.
Automatic closure of the inlet air flow when the filter plug is unscrewed avoids accidental air escape into the surrounding atmosphere and makes filter replacement more comfortable and quicker. Since separated flow cut-off cocks are not required, the device is cheaper and less bulky.
Turning back to FIG. 2 , the outlet 113 after discharge of the condensate directly leads to a regulation valve 212 provided with a closure member 240 that, urged by a spring 241 , closes passage to the outlet 12 . The closure member 240 is operated for opening by a control piston 242 which is acted upon, on the side towards the closure member, by the outlet pressure (through a passage 243 ) and, on the side opposite to the closure member, by a control pressure (through a passage 213 ). Thus a pressure regulating valve 212 of the differential type is obtained, i.e. a regulation member that is movable by means of the opposite thrusts produced by the pressure coming out of the regulator itself and by the pressure at the piloting inlet 213 .
The piloting inlet is controlled by a piloting module or unit, generally denoted at 215 , to perform, among other things, the function of progressive starting.
An advantageous embodiment of the piloting unit 215 is shown in FIG. 4 (in an extended view for better understanding). This unit 215 comprises an inlet 230 that will be connected upstream of valve 212 (through a passage 214 , not shown in FIG. 2 ), and an outlet 211 directed to the outlet connector 12 .
As clearly shown in the circuit diagram drawn under module 215 , between the inlet and outlet there is the presence of the pressure regulator 212 being controlled by the piloting inlet 213 .
Connected upstream of regulator 212 is the inlet of a secondary circuit 214 leading to a piloting unit 215 supplying the piloting command 213 to valve 212 .
The piloting unit comprises a progressive starting device 216 fed from the inlet 214 and sending air from the outlet 226 to the piloting command 213 .
In particular, device 216 comprises an inlet duct 217 connected to the inlet 214 , possibly through further control members to be described in the following. Duct 217 is divided into a main branch 218 , connected with the outlet 226 through an on-off valve or closure member 219 pushed for closure by a spring 220 , and a secondary branch 221 reaching the outlet 226 through a throttled passage 222 . Throttling 222 can be advantageously obtained in an adjustable manner by means of a pin 223 axially movable through an adjusting hand grip 224 .
A distributor or slide valve 225 exerts pressure on the closure member 219 in the direction of the opening thereof, against the action of spring 220 , due to the pressure to which it is subjected that is created in the outlet duct 226 . In this manner, the flow rate established by the pin produces a gradual pressure increase in the outlet duct until the thrust present on the side downstream of the closure member 219 overcomes the thrust on the upstream side and the closure member opens the main duct 218 to the outlet. It is apparent that pressure variation on the outlet 226 is used to consequently control operation of valve 212 that will thus produce a corresponding pressure variation in the outlet line 211 . Obviously the variation on the outlet 211 takes place irrespective of what is connected therewith.
Thus a perfect progressive starting is obtained under any load condition of the line. Reaching of the condition of full operation of the main circuit is also ensured irrespective of the presence of possible small pressure losses on the main circuit itself.
In the advantageous embodiment described, the true progressive starter acts on piloting of a valve instead of being directly placed on the main line, which on the contrary happens in the known art.
Such a structure also offers other advantages. The progressive starter 216 must be sized for the (very reduced) pilot flow rate necessary for regulator 212 and not for the much bigger flow rate of the main line 211 . This enables a progressive starting unit to be made which is of much more reduced bulkiness than in the solutions of the known art. The intrinsic sturdiness of the unit is also favored.
The piloting circuit of valve 212 with which the progressive starter is connected can also advantageously be a pilot circuit for pressure regulation on the main line. In fact, if along line 214 a known pilot pressure regulator 227 is placed, pressure stabilization on the outlet line 211 occurs during normal operation after the progressive starting. In addition, also provided in series with the pilot regulator can be a manual valve 228 and/or an electric valve 229 , of the type 3/2. Advantageously, as shown in FIG. 4 , valve 228 can be inserted in the body of the progressive starter. Valves 228 , 229 enable opening and closure of valve 212 to be carried out in a controlled manner. Thus an efficient piloted regulator of reduced bulkiness and high sturdiness is obtained.
At this point it is apparent that the intended purposes have been achieved by providing an integrated unit having many functions while being of reduced sizes, said unit also offering high efficiency, reliability and sturdiness. It is clear that an integrated unit manufactured in accordance with the invention can be easily positioned in reduced spaces while always maintaining high accessibility and ease of use and maintenance. It is also apparent that the manufacturing costs can be greatly reduced as compared with those of the known art according to which separated elements to be assembled are provided. In particular, use of a monobloc body between the inlet and outlet of the unit and enclosing most of the facilities required further reduces costs and bulkiness and prevents many possibilities of leakage. In the advantageous embodiment shown the whole unit is substantially formed of two bodies, the main one 20 , with the filter, the controlled valve 212 and all the ducts between the inlet and outlets, and a secondary body implementing the control module 215 . Due to the front arrangement of the displays and commands, the device can be easily mounted on a panel.
Obviously, the above description of an embodiment applying the innovative principles of the present invention is given by way of example only and therefore must not be considered as a limitation of the scope of the patent rights herein claimed.
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An integrated unit for air treatment in pneumatic systems comprises a box-shaped body provided with an inlet for the air to be treated and at least one outlet for the treated air and holds devices for treatment and regulation of the air flow between the inlet and outlet. The devices consist of at least one filter device, one pressure regulator and one progressive-starting device.
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This application is a divisional application of U.S. Ser. No. 08/260,488, filed Jun. 15, 1994, now pending, which is a continuation of U.S. Ser. No. 07/881,677, filed May 12, 1992, now abandoned, which is a continuation-in-part of application Ser. No. 07/648,655, filed Jan. 31, 1991 now U.S. Pat. No. 5,112,635, which, in turn, is a continuation-in-part of application Ser. No. 07/375,241, filed Jul. 3, 1989, now abandoned, of the same title and by the same inventors, for which as to common disclosures, the benefit of the earliest filing dates is claimed.
DESCRIPTION
1. Technical Field
This invention relates to an apparatus for and method of applying a liquid coating composition to a moving web of paper, and more particularly to a coating apparatus and method involving new and improved applications of an inverted trailing blade type. The invention is principally concerned with the application of heavier weight coatings, e.g., 51/2 and more pounds per side per ream, to paper webs traveling at ultra-high speeds of 3,000, 4,000 and more feet per minute.
2. Background Art
U.S. Pat. No. 4,250,211 discloses a novel inverted blade type apparatus and paper coating method that has come to be known as the "short dwell time application" or "SDTA" method and apparatus. The SDTA coater has essentially revolutionized the paper coating art.
The present invention provides a new and improved coating apparatus and method which utilizes, in a specific non-conventional interrelationship, modifications of and improvements upon SDTA and other web coating technologies.
A conventional coater of the trailing blade type includes means for applying a liquid coating composition to a moving web of paper, usually while the web is supported and carried by a resilient backing roll, together with a doctor blade located on the trailing side of the applicator and bearing under pressure against the roll supported coated web to level the applied coating. In general, an excess of coating material is applied to the web, and the trailing blade then meters or removes the excess while uniformly spreading the retained coating onto the web surface.
A first generation of blade coating apparatus, known as the "pond" or "puddle" coater, is comprised essentially of a blade angled downwardly toward and contacting the backing roll on the downwardly moving, incoming side of the roll and forming therewith a reservoir for coating material. The web is moved on the backing roll continuously through the reservoir and the "pond" or "puddle" of coating material therein, whereupon the exposed surface of the web picks up coating material which is struck off and leveled to the desired final thickness or coat weight as a consequence of passage of the web through the nip defined between the blade and the backing roll. Examples of this type of coater are shown in Pulp & Paper, Apr. 29, 1963, pp. 56-58, Paper Trade Journal, Oct. 27, 1969, pp. 58-62 and Paper Trade Journal, Feb. 22, 1971, p. 56.
A variant on the pond type coater, publicized as the Kohler Coater, eliminates the backing roll, disposes the pond or puddle in the horizontal plane, moves the web across the surface of the pond, and utilizes a variable pressure air knife to press the paper web against the blade at the web outlet end of the pond. The Kohler Coater, which is not known to have gained commercial acceptance, is disclosed in Kohler U.S. Pat. No. 3,113,884, Colgan U.S. Pat. No. 3,083,685; and articles appearing in the June 1959 issue of The Paper Industry, p. 232; the Jun. 8, 1959 issue of Paper Trade Journal, pp. 31-32; the February 1960 issue of Tappi, pp. 183-187; Pulp and Paper, Second Edition, Vol. III, Interscience Publishers, pp. 1565-1566; and Pulp and Paper Manufacture, Second Edition, Vol. II, 1969, McGraw Hill Book Company, pp. 510-511.
A second generation of blade coating apparatus is comprised of a dip roll applicator, which usually bears against the roll supported web at or adjacent the bottom dead center position of the roll, and a blade spaced downstream from the dip roll and converging toward and contacting the roll supported web, usually on the upwardly moving, outgoing side of the roll. Since this results in the blade converging upwardly into engagement with the roll supported web, the blade is known as an inverted trailing blade. As the web moves with the backing roll, the dip roll is rotated through a reservoir of coating liquid and picks up and transfers to the web an excess of coating liquid. The web then travels to the inverted blade where the excess coating liquid is removed from the web and the retained coating is leveled to the desired final coat weight thickness. Examples of the dip roll applicator with inverted blade (known by the acronym "drib") are disclosed in Rush, U.S. Pat. No. 2,746,877; Dickerman, et al., U.S. Pat. No. 2,949,382; Brezinski, U.S. Pat. No. 3,202,536; the Apr. 29, 1969 issue of Pulp & Paper, p. 57, and the Oct. 27, 1969 issue of Paper Trade Journal, pp. 60-61. In installations wherein a pool of coating liquid is accumulated at the nip between the two rolls, the coater may also be known as a "flooded nip" coater. Another version, involving the use of several applicator rolls in sequence, called the Champflex Coater, is disclosed at pages 56-57 of the Apr. 29, 1963 issue of Pulp & Paper. Also, dip roll applicators may be used in combination with other coaters for precoating or prewetting the web, as is shown for example in the illustration of the Kohler Coater in Pulp and Paper Manufacture, p. 511, and also in Damrau U.S. Pat. No. 4,250,211 and Damrau U.S. Pat. No. 4,310,573.
A major shortcoming of dip roll coaters is the development of a film split pattern in the final coated web, i.e., the appearance in the coating of substantially continuous longitudinal stripes or lines, as web coating speeds are increased above 2,500 feet per minute and coatweights exceed about 51/2 bone dry pounds per side per 3,300 square foot ream.
A third generation of blade coater, called the flexible blade or "Flexiblade" Coater, is comprised of a closed, pressurized, coating application chamber which sealingly engages the roll supported web, usually near the bottom of the backing roll, and has a back, rear or outgoing wall comprised of a flexible blade for spreading the coating material uniformly on the web surface. The "Flexiblade" Coater made by The Black-Clawson Company is disclosed in Jacobs U.S. Pat. No. 3,079,889 and in an article appearing in the Apr. 8, 1963 issue of Paper Trade Journal. It is also briefly described at p. 57 of the Apr. 29, 1963 issue of Pulp & Paper as well as other trade periodicals, both U.S. and foreign.
Other flexible blade coaters employing a closed or sealed, pressurized application chamber are described in U.S. Pat. No. 2,796,846 to Trist and U.S. Pat. No. 3,273,535 to Krikorian.
In another variant of the sealed chamber type of coater, coating liquid under pressure is extruded onto the web in the closed application chamber and an excess of coating is metered onto the traveling web by a metering bar at the rear or outgoing end of the chamber and the excess is then removed and the coating leveled to its final coat weight thickness by an inverted trailing blade engaging the web downstream from the metering bar. Patents describing coaters of this type include Galer, U.S. Pat. No. 3,192,895; Hunger, U.S. Pat. No. 3,486,482 and Nagler, U.S. Pat. No. 3,518,964. Of the three, the patent to Hunger U.S. Pat. No. 3,486,482, is the most representative.
The closed chamber type of coaters suffered the problem of excessive web breaks due to engagement of the traveling paper web with the mechanical sealing means required at the incoming, front or upstream end of the closed application chamber. Efforts to alleviate the problem, for example, by the use of flexible blade seals, such as those of Trist, or by spacing the Jacobs et al. seal member slightly from the web as suggested in the literature, failed to cure the problem. As a consequence, closed chamber coaters, including the Black-Clawson "Flexiblade" Coater, have been substantially if not entirely replaced by subsequent developments in paper coating technology. The above described variant thereof, as represented by the patent to Hunger, is not known to have been used commercially at all.
A fourth generation of blade coater, which was introduced by Black-Clawson as a replacement for the "Flexiblade" Coater, is characterized by an inverted trailing blade preceded by a fountain applicator which, like a dip roll, applies an excess of coating liquid to the web, which excess is subsequently removed and the coating leveled to its desired thickness by the trailing blade. Apparatus of this type, which are called Fountain Blade Coaters, are described in the Mar. 13, 1967 and May 13, 1968 issues of Paper Trade Journal (at pp. 52-53 and 64-67, respectively) and in a paper presented by Black-Clawson at a Tappi conference in 1978, and are disclosed in detail in the patents to Phelps et al., U.S. Pat. No. 3,418,970, Penkala et al. U.S. Pat. No. 3,453,137 and Coghill, U.S. Pat. No. 3,521,602. A competitive apparatus, employing a jet applicator rather than a fountain applicator, is described in the German periodical Das Papier, No. 7, 1972, pp. 332-338, at page 334. Similar disclosures appear in an article by Ing. Josef Geistbeck, appearing in the German publication Walzen Und Glattschaberstreichanlagen, and in German Auslegeschrift No. 2359413.
With these prior art fountain and jet applicators, the amount of excess coating that is delivered to the trailing blade is purportedly metered onto the web by a metering or overflow strip which is located at the downstream edge of the applicator and adjustably spaced from the surface of the web to accomodate the escape of coating liquid between the web and the overflow strip. In use, these coaters encounter difficulties when running at high speed because the web catches on the metering bar and tears, thereby producing web breaks and causing machine down time and loss of production.
Some prior art coaters inherently employ a relatively long coating liquid dwell or soak time on the web, i.e., the time interval between the initial application and final blading of the coating. As a result, the water portion of the coating composition, as well as the water soluble or dispersable materials contained therein, migrate into the moving web at a more rapid rate than the pigment and eventually cause an undesirable imbalance in the coating constituents and their rheological properties. Long soak periods are also incompatible with the application of successive wet coats without intervening drying, i.e., wet on wet coatings, because the successive coat tends to migrate into and contaminate the previous coat.
In an effort to control soak time, Black-Clawson introduced a variation of its fountain blade coater wherein the fountain applicator and the doctor blade are separate assemblies and are relatively adjustable toward and away from one another in order to vary the dwell time of the coating on the web between application and doctoring. This coater, called the Vari-Dwell Coater, is described in the proceedings of the Tappi 1986 Blade Coating Conference, pages 109-113, and the Tappi 1987 Coating Conference, pages 141-149.
The problems associated with long dwell times are discussed in U.S. Pat. No. 3,348,562 to Neubauer, who discloses a coater wherein a narrow stream of viscous coating is extruded onto an inverted trailing blade that defines a nip region with the roll supported web. Since the coating is bladed immediately after application, soak times are purportedly kept to a minimum. However, the coating application is such that the coating material is unpressurized after leaving the orifice and is supported on the blade or trailing side only, with the leading side of the stream being unsupported and exposed to the environs in the zone of application. Consequently, the coating material is not properly or uniformly applied to the web. Disclosures of a related nature are contained in U.S. Pat. No. 3,484,279 (FIG. 3) to Clark et al. and U.S. Pat. No. 3,070,066 to Faeber.
The fifth generation of blade coater comprises the short dwell time application coater or "SDTA" coater which is rapidly replacing the prior art blade coaters. In essence, the closed chamber, flexible blade, fountain blade and jet applicator coaters have been rendered obsolete, and the puddle and roll type coaters are being relagated to web precoating or prewetting functions in wet on wet coating systems. The short dwell time or "SDTA" coater is disclosed in detail in U.S. Pat. No. 4,250,211, and its advantages are discussed in the May 1984 issue of Pulp & Paper, pages 102-104.
The "SDTA" coater is characterized by a coating application chamber having a very small dimension in the direction of web travel, a doctor blade pressure loaded against the coated web at and defining the downstream or web outlet end of the chamber, a novel liquid seal formed within a fairly generous gap defined between the applicator and the web at the upstream or web inlet end of the chamber, and means for supplying coating liquid to the chamber under pressure and in such copiously excess quantities as to cause a continuous high volume flow of coating liquid through the gap out of the upstream or front end of the chamber in a direction opposite to the direction of web travel, thereby to form and maintain a liquid seal within the gap and to maintain the coating liquid under pressure in the chamber and as it is applied to and doctored off the web; the doctoring occuring immediately at the downstream end of the application zone while the coating liquid is maintained under pressure. The flow of excess coating liquid through the gap defined between the web and the front edge of the application zone, in the direction reverse to the direction of movement of the web, is such that the gap is continuously and completely filled with reversely flowing coating liquid in quantity sufficient to: (a) close and seal off the gap at the front edge of the zone to maintain the pressure application of the coating liquid to the web within the application zone; (b) strip air off the web as it approaches and enters the application zone, thereby to eliminate air induced skips and voids in the layer of coating applied to the web and insure uniform overall coating of the web; (c) prevent entrainment of air in the coating liquid in the application zone and in the coating liquid that is applied to the web, thereby to eliminate coating imperfections due to the presence of air bubbles in the coating on the web; (d) prevent entry of foreign matter through the gap into the application zone and the coating liquid therein; and (e) continuously clean and purge the application chamber and application zone to insure the integrity, homogeneity and uniform distribution of a continuously fresh supply of coating liquid within the application zone, and to ensure that no foreign matter or impurities, e.g., lumps or coagulated coating, reach the doctor blade where they could cause scratching of the coating or create other problems deleterious to the coating process, or result in web breaks.
Due to the facts that the moving web of paper is pressed firmly, continuously and tightly against the surface of the backing roll by the reversely flowing liquid seal at the front or web entry end of the application zone, by the pressure of the coating liquid within the application zone, and by the pressure loaded doctor blade at the rear or web exit end of the zone, the web cannot catch or snag on coater components and the web breaking and other disadvantages of prior art coaters are eliminated. Consequently, coating compositions can be applied to the web under pressure within a short dwell time, free of skips and voids even at very high web speeds. The SDTA coater has proven itself in use at speeds up to 4000 feet per minute ("fpm") and beyond to apply a more uniform layer of coating onto a web than any prior art coater.
Characteristics of the applied coating can be varied or enhanced by precoating the web, e.g., by a roll applicator as shown in U.S. Pat. No. 4,250,211 and improvement patent, U.S. Pat. No. 4,310,573, or by use of an internal leveling blade as disclosed in improvement patent, U.S. Pat. No. 4,369,731, or by use of a second, internal liquid seal as disclosed in improvement patent, U.S. Pat. No. 4,452,833, or by use of other improvements of note such as disclosed in U.S. Pat. No. 4,396,648, 4,440,105, and 4,503,804.
A proposed variation on the SDTA coater, one version of which is disclosed in FIG. 3 of Wohlfeil patent, U.S. Pat. No. 4,706,603, involves essentially closing off the gap between the coater and the web at the upstream or web inlet end of the coating application chamber and draining excess coating from the chamber via drain holes in the upstream or front wall of the application chamber; the rate of drainage being such as to maintain the coating liquid in the chamber under pressure and to insure a sealed relationship between the web and the coater at the web inlet end of the application zone.
Another variant, a version of which is disclosed in U.S. Pat. No. 4,963,397 to Michael A. Mayer et al., involved utilization of a short dwell type of apparatus to rework a previously applied excess layer of coating liquid, e.g., a dip roll applied excess layer, to distribute over the web a more uniform layer of the coating; specifically, a layer of coating that is free of the film split pattern of dip rolls when operated at speeds above about 2,500 fpm; the blade of the short dwell coater being used to remove excess coating from the web and to smooth and level the coating to the desired wet film thickness and coat weight; the excess coating removed by the blade being drained away via the SDTA, e.g., in a manner such as disclosed in Wohlfeil. For another variant, see also U.S. Pat. No. 4,859,507 to Wayne A. Damrau.
While the SDTA, including the above-described variation and variants thereof, has significantly advanced the state of the art, it has not provided a final solution to all the expectations of the paper coating industry. As the industry presses forward to attain even greater capacity, efficiency and economy in the production of coated papers, even the SDTA coater has on occasion produced coated papers that would not satisfy the increased demand for high quality coatings at higher web speeds. In particular, when applying heavier weight coatings, for example, 51/2 and more pounds per side per 3,300 square foot ream, to the higher grades of paper webs, e.g., groundwood free merchant grades, at ever increasing production speeds, SDTA coatings, though of substantially uniform thickness and free of skips and voids, have exhibited decreased surface smoothness and streakiness in the direction of web travel through the coater, i.e., so-called machine direction or "MD" streakiness. Precoating or prewetting the web or reworking a previously applied excess coating on the web will not eliminate these problems. Dip roll applicators in particular encounter their own inherent limitations at web speeds in the order of 2,800 fpm due to splitting of the film of coating liquid being applied by the roll, resulting in a nonuniform coating having a longitudinally streaked or striped appearance, i.e., film split pattern.
While the SDTA coater and the above-described variants thereof can in most instances eliminate the film split pattern of the dip roll coating, MD streakiness and/or unacceptably diminished surface smoothness, i.e., surface roughness, may still result. Thus, whether used alone or in combination with a dip roll applicator, existing apparatus and methods, when operated at higher speeds to apply heavier weight coatings, may not in all cases produce a coated paper that will satisfy the exacting demands of the high quality printing, graphic arts and publishing trades.
SUMMARY OF THE INVENTION
The present invention comprises an improved paper coating apparatus and method capable of extremely high speed production of coated papers fullfilling the exacting demands of the trade, and specifically eliminating both film split pattern and MD streakiness in heavier weight coatings produced at high web coating speeds. The invention provides an improved coater and coating method making non-conventional use of SDTA type applicator apparatus for distributing excess coating liquid in a highly turbulent state over the surface of the web, and utilizing primary and secondary trailing blades for effecting precisely controlled sequential doctoring of the excess to the final wet film thickness of coating desired on the web; the primary blade being located at the downstream or web outlet end of the distribution zone of the apparatus and doctoring onto the web a substantially uniform layer of coating having a limited or controlled thickness which is in excess of the desired final wet film thickness (and significantly in excess of that conventionally applied by an SDTA coater); the secondary blade being spaced downstream from the primary blade and being physically and hydrodynamically isolated from the coating application zone; the secondary blade doctoring the primary blade's limited excess of coating off the web and leveling and smoothing the retained coating to the final wet film thickness desired.
As used in accordance with the present invention, the SDTA type of apparatus is effective to distribute over the entire surface of the high speed traveling web, within a limited application zone, an excess of coating that is entirely free of skips, voids, film split pattern and other imperfections, except MD streakiness and surface roughness. Due to the liquid turbulences, eddy currents and other hydrodynamic disturbances that are generated in the coating liquid in the application zone of the apparatus at very high web speeds, the coating medium in the zone exhibits extreme hydrodynamic impulse variations and fluctuations across the width of the web which cause transversely shifting variations across the width of the web in the thickness or caliper of the coating liquid being applied to the web, i.e., cross direction or "CD" caliper variations, which result in overall MD streakiness, diminished surface smoothness, and other imperfections in the final coated web.
According to the present invention, the primary blade is utilized to contain and isolate the hydrodynamic pressure fluctuations and impulse forces, and to gain a preliminary degree of control over the coating to be retained on the web, but without overwhelming the primary blade. First, the primary blade is utilized to isolate the hydrodynamic eddy currents and turbulences with the application zone and to confine the same therein. Second, the primary blade is employed to doctor onto the moving web an excess of coating liquid in the form of a relatively quiescent layer having an overall high degree of uniformity, except for small but nevertheless unacceptable variations in CD caliper profile. Third, the primary blade effects a controlled doctoring of this quiescent layer to a limited thickness just sufficiently in excess of the desired final wet film thickness to accomodate a subsequent final wet film doctoring of the liquid on the web under optimum blading or doctoring conditions.
Even with a relatively light mechanical loading thereon, the primary blade in the coater of the invention results in transport to the secondary blade, on the high speed traveling web, of a generally uniform, relatively quiescent layer of coating liquid of precisely controlled and limited excess thickness that is free of skips, voids and other anomalies or abberations, other than the unacceptable variations in CD caliper profile.
The secondary blade of the coater of the invention is spaced downstream from the primary blade and is thereby isolated from the turbulences and hydrodynamic impulses generated in the application or distribution zone. Because the secondary blade is isolated from such forces and disturbances, and because the primary blade applies a carefully controlled and uniform though potentially imperfect layer of excess coating onto the web, and because the caliper variations in the layer of coating on the web are instable and continuously shift back and forth transversely of the web, the hydrodynamic pressure exerted by the coating medium on the secondary blade is extremely uniform and constant across the entire width of the blade. The secondary blade can therefore exert a constant doctoring pressure or force on the coated web substantially uniformly across the width of the web, thereby to produce an extremely uniform coating lay on the web, free of film split patterns, CD caliper variations and MD streakiness.
In addition, the surface of the final coating on the web exhibits increased smoothness over conventionally applied coatings, and as well, a significant decrease in blade scratches. The decrease in scratches may be attributed to the fact that the primary blade is continuously flushed with the excess coating liquid in the application zone so that any debris in the coating liquid supply is quickly flushed away from the primary blade and does not by-pass the primary blade to interfere with optimum operation of the secondary blade. Thus, use in accordance with the invention of two spaced blades working sequentially on the same coating results in a coating lay that is very smooth surfaced and substantially scratch free.
Unlike prior art coating methods and apparatus such as some fountain coaters and dip roll coaters, the method and apparatus of the present invention results in a paper smoothness which is relatively high at high web speed and is relatively constant at all web speeds, i.e., produces a paper whose smoothness is independent of the web speed at which it was coated. Additionally, again unlike such prior art coating methods and apparatus, the method and apparatus of the present invention produces paper that is higher in gloss and declines less in gloss as the web speed at which it was coated increases.
The dwell time of the relatively quiescent layer of coating liquid on the web, occasioned by the spacing between the primary and secondary blades, is beneficial in that it enables the boundary layer of coating next to the web to become somewhat immobilized, which immobilized coating uniformly supports the tip of the secondary blade so that the final leveling and smoothing of the applied coating takes place where the coating is quite stable, thereby to provide a very uniform coating entirely free of MD streakiness, and exibiting smoothness and other quality improvements over conventionally applied coatings.
The invention further resides in preferred time intervals between the two blading operations and preferred minimum and maximum rates of delivery of excess coating liquid from the primary blade to the secondary blade to insure proper performance of the final blading operation. The invention also includes various precoating and/or web preconditioning techniques useful in producing extremely high quality coatings at very high production speeds.
The invention thus engenders a further step forward in the art of blade coating, and envisions improved multi-stage wet on wet coating methods.
Other objects and advantages of the invention will become apparent from the following detailed description, considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration, in side view, of a first embodiment of a paper web coating apparatus provided in accordance with the invention including sequence in the direction of web travel on a web supporting roll, of a dip roll applicator, a preliminary treating or doctoring device, and the coater of the invention;
FIG. 2 is a schematic illustration of a second embodiment of a paper web coating apparatus provided in accordance with the invention including, in sequence in the direction of web travel on a web supporting roll, of first and second ones of the coating apparatus of the invention;
FIG. 3 is a side view, partly in vertical section, of a unitary coater provided in accordance with the invention;
FIG. 4 is a graph of Parker Printsurf smoothness versus web speed for several prior art methods and coaters and also the present invention where after coating the paper was supercalandered at the same conditions; and
FIG. 5 is a graph of Tappi 75° Gloss versus web speed for several papers coated by prior art methods and coaters and also the present invention where after coating the paper was supercalandered at the conditions.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The following is a description of the best mode presently contemplated by the applicants for carrying out the preferred embodiments of their invention. While the embodiments of the invention shown in the drawings are illustrated schematically in side view only, it is to be understood that the drawings represent fairly massive machine components having substantial width, e.g., 156 inches or more, in the direction perpendicular to the plane of the paper. Schematic illustrations suffice for purposes of disclosure to persons of ordinary skill in the art inasmuch as the individual machine elements are known in the art.
Referring to the drawings, and particularly to FIGS. 1 and 2, a continuous web of paper traveling in the direction of the arrows at speeds of at least 3,000 feet per minute ("fpm"), and up to 4,000 and 5,000 fpm and beyond, is guided into engagement with the surface of a large diameter web backing roll 10 rotating in the direction of web travel and having a resilient surface layer 12, the web preferably wrapping the roll over an arc of about 140 degrees.
The coating apparatus of FIG. 1 is comprised of a web backing roll 10 and, insequence in the direction of web travel about the roll, a dip roll applicator 20, a first coating doctoring device 30, and the coater 40 of the invention, which is comprised of a non-conventionally operated short dwell time or SDTA applicator 42, a primary inverted trailing blade 44, and a secondary inverted trailing blade 46. The essence of the invention resides in the coater comprising the applicator 42, the primary blade 44 and the secondary blade 46. However, a dip roll applicator 20 has been shown as part of the apparatus because a dip roll can in many cases enhance the overall coating operation, especially when applying heavier coatings, by forcing coating composition into the interstices, voids and valleys on the surface of the web so that the subsequent coating can be applied to a more uniform surface which has been pretreated to provide for better holdout of the final coating. This in turn will impart a better ink holdout characteristic to the coated paper to enhance its printability.
Also, by mounting all of the coating instrumentalities for movement toward and away from the web, as indicated by the arrows, to accomodate selective use of the same, the apparatus of FIG. 1 provides a coating station having great universality of use.
FIG. 2 illustrates a coating apparatus provided in accordance with the invention and with which the ultimate in wet on wet coating techniques can be practiced. This apparatus comprises two of the coaters of the invention 40a and 40b mounted in sequence on a common web backing roll 10; the coaters being comprised respectively of an applicator 42a, a primary blade 44a and a secondary doctoring device 46a, and an applicator 42b, a semi-final blade 44b and a final blade 46b.
FIG. 3 illustrates one embodiment of a physical construction of a unitary coater provided in accordance with the invention and comprised of an applicator 42, a primary trailing blade 44 and a final trailing blade 46.
The present invention embodies new and improved utilizations of SDTA coating technology in order to attain now and improved results heretofore unattainable. However, the construction of the aplicator 42 as utilized in connection with the invention is, in general, much the same as illustrated and described in U.S. Pat. Nos. 4,250,211, 4,310,573, 4369,731, 4,396,648, 4,440,105, 4,452,833 and 4,503,804, the teachings of which are incorporated herein by reference. As shown in the drawings, each applicator 42 comprises a coating composition receiving chamber 51 to which coating liquid is delivered from a source of supply in large quantity and under pressure; suitable pumps and piping (not shown) being provided for that purpose. The coating liquid passes from the chamber 51 through a restricted orifice 52, which produces a highly uniform and evenly distributed flow of coating liquid into a pressurized coating outlet slot or application zone 53. The zone 53 is preferably closed at its rearward end by the primary doctor blade 44 which sealingly engages the coated web under pressure at the downstream, back or web exit end of the zone. A pair of edge dams or seals (not shown) seal off the opposite side edges of the zone. At the front or web entry end of the zone, an orifice plate 55 having an upper edge spaced from the web defines with the web a gap 56 within which a reversely flowing coating liquid seal is established during operation of the coater. The coating flowing reversely through the gap 56 is returned via a channel 57 to the coating liquid source of supply for recycling and recirculation to the coater.
Esoteric coating compositions are not required for practice of the invention. Conventional compositions for producing enamel coated printing papers for the graphic arts and publications trade are preferred. A suitable composition comprises a starch-latex adhesive system with clay and/or calcium carbonate at 62% solids and a Brookfield viscosity of 5200 centipoise ("cps") at 20 revolutions per minute ("rpm"). Many other suitable coating compositions are known in the art.
As indicated by the arrows in FIGS. 1-3, the applicator 42 is adapted to be moved toward and away from the roll 10 to accomodate threading of the web through the coater and to accomodate variable positioning of the applicator relative to the roll supported web.
Coating liquid is supplied to the chamber 51 of the applicator 42 under pressures and in copious quantities sufficiently in excess of that to be applied to the web to cause coating liquid to completely fill the gap 56 and to flow continuously through the gap 56 in a direction opposite to the direction of web travel substantially uniformly across the entire width of the application zone. The size of the gap 56 and the pressure and the quantity of the coating liquid forced through the gap in a direction opposite to the direction of travel of the speeding web are correlated to one another to ensure that the gap is completely and continuously filled with reversely flowing coating liquid sufficient to:
a) completely close the gap 56 and seal off the front edge of the application zone 53 to ensure pressure application of the coating composition to the web;
b) strip air off the surface of the web as it approaches and enters the coating application zone 53 to prevent air induced skips and voids in the coating subsequently applied to the web;
c) prevent entrainment of disruptive air bubbles in the coating liquid within the application zone and the coating liquid applied to the web;
d) prevent entry of foreign matter into the application zone and the coating liquid therein; and
e) continuously purge the entirety of the coating delivery lines, the inlet chamber 51, the restricted orifice 52, the application zone 53 and the gap 56, thereby continuously to ensure the integrity, homogeneity and uniform distribution throughout the application zone of a continuously fresh supply of coating liquid free of foreign matter and impurities.
Because of the advantages that are achieved by the above described construction and mode of operation of the illustrated applicator 42, it is preferred in practice of the present invention to an apparatus and a method of operation as described, i.e., wherein coating liquid is applied under pressure to the web within a limited application zone 53 and copious quantities of the coating liquid are caused to flow in a direction opposite to the direction of web travel through a gap 56 at the front or upstream edge of the application zone 53 to form a liquid seal within such gap. However, it is believed feasible to utilize the proposed variation disclosed in FIG. 3 of Wohlfeil patent, U.S. Pat. No. 4,706,603 and/or the variants disclosed in Mayer et al., U.S. Pat. No. 4,963,397 and Damrau, U.S. Pat. No. 4,859,507, should one desire to do so. Thus, references to the application zone 53 and to the distribution of coating liquid in a turbulent state over the surface of the web should be understood to encompass variants as well as the preferred embodiment.
When constructed and operated in accordance with the preferred guidelines described, prior art SDTA coaters have been effective to apply a very uniform coating to the web. With and without a dip roll, the SDTA has produced extremely high quality coatings of various weights on a variety of base sheets at various speeds. Commercial operations are routinely conducted at 3,250 fpm for applying coat weights up to about 5 to 6 bone dry pounds per side per 3,300 square foot ream to groundwood paper webs, and experimental operations on lighter weight coatings have been observed at speeds up to 5,000 fpm. However, when applying coat weights in excess of about 51/2 pounds per ream per side to the higher quality grades of paper, e.g., merchant grade web offset papers, especially free sheets having no groundwood, SDTA coatings tend to exhibit a streaky pattern, i.e., MD streakiness, as web speeds approach and exceed 3,000 fpm.
Having found a method that cures the problem, i.e., by virtue of the present invention, it can now be said, with the benefit of hindsight, that certain factors contribute markedly to MD streaking at higher coat weights. First, the increase in the velocity of the web passing through the distribution or application zone 53 in a given unit of time so intensifies the development of primary vortices and secondary vortical fluid motions and/or other disturbances in the coating liquid in the zone that irregular and variable hydrodynamic impulse forces are exerted by the liquid against different portions of the blade 44 across the width of the coater. Second, because the blade 44 is pressed mechanically against the web at less pressure for higher coat weights than it is for lower coat weights, the blade is less resistant to irregular and variable hydrodynamic impulse forces imparted thereto by the liquid and will permit passage of more coating under the portions thereof having a high hydrodynamic liquid force thereon than under the portions thereof having a lesser hydrodynamic liquid force thereon. This results in variations across the width of the web in the thickness or caliper of the layer of coating applied to the web. Such variations, though very slight, render the coated paper unacceptable. Because the locale of the irregular and variable impulse forces acting on the blade will inherently shift back and forth in directions transversely across the web due to the irregular nature of the turbulence of the liquid in the application or distribution zone, these cross direction or "CD" variations in the caliper of the coating will not simply leave one or more continuous longitudinal streaks in the coating, but instead will impart an overall streaky appearance to the coated web. The streaky appearance renders the coated paper unacceptable for quality printing and the graphic arts.
In contrast to prior art SDTA practices, wherein the SDTA coater is self-contained and the SDTA doctor blade is mechanically loaded at a sufficiently high pressure against the roll supported web to level the coating composition to final wet film thickness, coat weight and surface smoothness, the present invention, in its preferred embodiment, teaches operation of the applicator portion of an SDTA in a non-conventional manner. Specifically, as used in accordance with the present invention at web speeds in excess of 3,000 fpm, the applicator 42 distributes coating liquid in a turbulent state over the surface of the high speed traveling web to impart thereto an excess of coating that is continuous and entirely free of skips, voids and film split pattern, but otherwise somewhat irregular.
The primary blade 44 of the invention is pressed against the roll supported web at a relatively low mechanical loading pressure adjacent the outlet end of the turbulent zone. Despite the light mechanical loading thereon, the primary blade 44 confines and isolates the highly turbulent mass of coating liquid within the application zone 53 and doctors onto the web a relatively quiescent layer of coating having a thickness in excess of the desired final wet film thickness of the coating on the web. Though the excess layer from the primary blade 44 will embody CD caliper variations and exhibit a streaky pattern, the layer of coating on the web is nevertheless a generally or substantially uniform layer; specifically, a much more uniform layer than can be applied with a dip roll or any other presently known apparatus.
In addition, even though the primary blade 44 is biased against the web at a relatively low mechanical loading pressure, the primary blade effectively controls the amount and overall average thickness of the coating applied to the web so that only a limited excess of coating liquid remains on the high speed traveling web; specifically, an excess providing for rates of delivery, within minimum and maximum limits, of excess coating liquid to the secondary blade 46 sufficient to accomodate optimum wet film doctoring at the secondary blade, but not so excessive as to overwhelm the hydrodynamic capacity of the secondary blade. With the coater of the invention, the amount or rate of delivery of excess coating liquid to the final blade is more accurately controlled, and is significantly less, than with any presently known coating apparatus.
Thus, primary blade 44 of the coater of the invention provides for delivery to the secondary blade 46 of the coater of a continuous, uniform, essentially quiescent layer of coating liquid of limited excess thickness that is free of skips, voids and other anomalies, except unacceptable variations in CD caliper profile.
The secondary blade 46 of the coater of the invention is spaced downstream from the applicator 42 and the primary blade 44 of the coater, in physical isolation from the hydrodynamic impulse forces generated in the application zone 53, and is pressed uniformly and tightly against the web to perform a final blading action on the non-turbulent essentially quiescent layer of coating liquid that is doctored onto the web by the primary blade 44. The blade 46 is mounted in a blade holder 61 which, as indicated by the arrows, may be moved toward and away from the roll 10 to accomodate threading of the web through the coater and to permit adjustment of the blade relative to the roll supported web. Excess coating removed from the web by the blade 46 is returned to the source of coating supply via a catch pan 62 and suitable piping 63 for recycling and recirculation to the applicator 42.
The excess amount of coating liquid on the web between the primary blade 44 and the secondary or final blade 46 must be adequate to maintain sufficient coating liquid at the nip between the blade 46 and the roll supported coated web to ensure that the final blading operation is carried out under wet blading conditions; to provide for adequate run off from the blade to purge the blade, flush away debris and keep the blade clean; and to prevent drying or coagulation of the coating composition on or before the final blade 46. On the other hand, the amount of excess should be limited to the extent feasible to accomplish the foregoing operational objectives and, at the same time, to minimize the work load on the final blade, to avoid overloading the blade hydrodynamically, and to avoid exceeding the capacity of the coater to dispose of excess coating liquid via the catch pan 62 and piping 63.
Also, the spacing between the blades 44 and 46 must be such as to provide a controlled dwell time of the coating on the web and assure optimum blading conditions at the final blade.
Assuming these conditions are satisfied, preferably in the manner and within the parameters explained in greater detail hereinafter, the layer of coating composition delivered to the blade 46 will result in imposition on the blade of a very uniform and constant hydrodynamic pressure across the entire width of the blade, essentially if not completely free of irregular and variable impulse forces. This is accomplished by reason of the facts that (a) the final blade 46 is physically removed from the application zone 53 and thus isolated from the nonuniform and turbulent hydrodynamic impulse forces generated within the zone 53, (b) the layer of coating doctored onto the web by the primary blade 44 is in fact essentially uniform, (c) the amount or thickness of the layer of coating liquid doctored onto the web by the primary blade is only of a minimal limited excess optimum for final wet blading, and (d) the CD caliper variations in such layer of coating are not constantly in the same location on the web, but shift back and forth transversely of the web, so that the layer of coating as it encounters the blade 46 is of an essentially uniform and constant thickness across the entire width of the coated web. The hydrodynamic pressure or impulse force of the coating medium on the final blade is therefore very uniform and constant across the entire width of the blade, and the blade can be mechanically loaded uniformly across its width to exert an essentially uniform and constant leveling and blading force on the coated web to impart thereto an extremely uniform coating lay free of CD profile variations and MD streakiness. The resultant uniform coating exhibits a significant increase in surface smoothness and a significant decrease in blade scratches.
Due to the fact that there is some dwell time of the excess coating on the web in the interval between the two blades 44 and 46, the boundary layer of coating immediately adjacent the surface of the web will become somewhat immobilized and the final blading will take place within this immobolized boundary layer or zone, where the coating is quite stable, so that the tip of the final blade 46 is uniformly supported by such layer and therefore functions more effectively to impart a uniform and smooth surfaced coating on the web.
Due to the construction and mode of operation of the coater of the invention, the coater is essentially free of self-induced or self-propogated breaks in the high speed traveling web. Specifically, as the moving web of paper approaches the preferred embodiment of the coater of the invention, it is pressed firmly, tightly and continuously over its entire surface area against the surface of the backing roll 10 by the liquid flowing reversely through the gap 56 at the front or web entry end of the coating application zone 53 and by the pressure of the coating liquid within the zone 53. Consequently, the web cannot catch or snag on the orifice plate 55 or any other coater components, and the web is fed in a firmly and smoothly supported condition to the primary blade 44. The blade 44 in turn applies an essentially uniform mechanical loading force on the roll supported web at the rear or web exit end of the zone 53. The web therefore leaves the blade 44 in firm, tight and continuous engagement with the surface of the roll, and with a generally uniform layer of coating thereon, so that the web moves without distortion or displacement relative to the roll to the blade 46 for fully supported, very uniform and smooth final blading of the coating thereon. Also, because the application zone 53 is so small and such intense eddy currents are developed in the coating liquid therein at high web speeds, the coating composition does not coagulate or develop lumps or particulate clumps that could lodge on either of the blades to cause streaks, scratches or breaks. Thus, web breakage and resultant downtime are rarely if ever caused by the coater of the invention.
To attain the best results from the coater of the invention, the applicator 42, the primary blade 44 and the final blade 46 should all contact the roll supported web within the lower quadrant on the upwardly moving side of the roll 10, i.e., intermediate the six and three o'clock positions as the coater is illustrated in FIGS. 1-3. In order to accomodate web pre-coating apparatus, such as illustrated in FIGS. 1 and 2, it will usually prove desirable, and it is therefore preferred, to have the tip of the final blade 46 contact the roll supported web at or in close proximity to the horizontal centerline of the roll 10 on the upwardly moving, outgoing side of roll, i.e., at the three o'clock position as the coater is illustrated in FIGS. 1-3. The tip of the primary blade 44 should contact the roll supported web from about 4 to about 24 inches upstream from the tip of the blade 46 when operating at web speeds of 3,000 to 5,000 fpm. With a conventionally or appropriately sized backing roll 10, such as a 50 inch diameter roll, we have found it preferable to have the primary blade 44 contact the web in the order of about 30-40 degrees upstream from the final blade 46, i.e., in the vicinity of the four o'clock position as illustrated in FIGS. 1-3. This location assures optimum operation of the applicator 42 and the blade 44; provides for adequate but not excessive dwell time of the coating on the web before final blading; provides sufficient space within which to mount the catch pan 62 and piping 63; and results in a compact physical construction that will accomodate installation of selected pre-coating apparatus between the bottom dead center position of the roll and the applicator 42, as is illustrated in FIGS. 1 and 2.
In addition, in order to achieve the above described mode of operation and attain the best results from the coater of the invention, it is necessary to observe and adhere to various operational criteria. In respect of the preferred embodiment of the coater of the invention, the upper edge of the orifice plate 55 of the applicator 42 should be spaced from the surface of the web by a dimension within the range of about 1/16 inch to about 1/2 inch, preferably within the range of 1/8 to 3/8 inch; the plate 55, as indicated by the double headed arrow thereon, being slidably mounted on the body of the applicator to accommodate such adjustment. Coating liquid is preferably supplied to the chamber 51 at a pressure in the range of from about 7 to about 100 inches of water (1/4 to 3.5 pounds per square inch, "psi"), and in quantities sufficiently in excess of that applied to the web to cause a reverse flow of coating liquid through the gap 56 adequate to completely and continuously fill said gap with reversely flowing coating liquid substantially uniformly across the width of the web. Reverse flow through the gap 56 should preferably be in the order of about 0.75 to about 2.0 or more gallons per minute ("gpm") per inch of web width.
With a sufficient amount of coating liquid delivered to the chamber 51, under sufficient pressure, the coating composition will be applied under pressure to the web within the application zone 53. The dimension of the zone 53 in the direction of web travel, depending upon web speed, may be in the order of from about 1/4 to about 4 inches, preferably about 1/2 to about 11/2 inches. In most commercial operations to date, the dimension has been in the order of about 3/4 to about 3 inches, usually about 1 inch, so that the distribution of turbulent coating liquid onto the web is of short duration, i.e., short dwell, in the order of about 0.0004 to about 0.0100 of a second.
The distributed coating is then immediately doctored, preferably while under pressure at the web exit end of the zone 53, by the primary blade 44. The blade 44 must be adjusted to press against the coating applied to the web in the zone 53 in such manner as to doctor onto the web a layer of coating having a thickness in excess of the desired wet film thickness of the final coating on the web. As above stated, the amount of the excess must be carefully controlled to insure delivery of excess coating liquid to the blade 46 in an amount and at a rate that will provide for optimum operation of the blade and prevent imposition of undue hydrodynamic impulse forces on the blade. On trial runs at web speeds of 3,000 fpm to 4,000 fpm, utilizing a coating composition having 62% solids, it has been found that the amount of the excess should be at least about 0.25 gpm per inch of blade width and should not exceed about 0.75 gpm per inch of blade width. Stated in inches of wet film thickness, the film doctored onto the web by the primary blade should be from about 0.0010 to about 0.0040 inch thicker than the desired final wet film thickness. Depending upon the final weight of the coating to be retained on the web after final blading at 46, and the amount of excess to be delivered from the primary blade 44 to the final blade 46, the pressure exerted on the coated web by the tip of the blade 44 should preferably be within the range of from about 1.0 to about 4.5 pounds per lineal inch ("pli").
Another, more accurate and less variable dependent, description of acceptable limits on the layer of coating between the two blades 44 and 46 would be to define the same in terms of bone dry coat weights per 3,300 square foot ream ("lbs/rm"). Based on the trial runs referred to above and assuming final bone dry coat weights within the range of 5 to 15 pounds per ream, the amount of coating metered onto the web by the blade 44 should be such as would result in bone dry coatings within the range of about 25 to about 85 bone dry pounds per ream. Based on a bone dry analysis, the layer of coating applied by the primary blade 44 should be in the order of about 2 to 10 times the final coat weight of the coating that is doctored to the web at the final blade 46.
With lesser excess flow rates than above stated, the amount of excess coating is not sufficient to purge and flush the blade 46 and to flow continuously from the blade into the catch pan 62. Coating solids build-up would occur and greatly hamper runnability of the coater. consequently, there would be no assurance that the blade 46 would operate cleanly in a wet layer continuously across the web, and coating in the vicinity of the blade 46 could potentially coagulate and impair the efficient operation of the blade, possibly causing blade scratches and streaks in the final coating. Excess flow rates greater than the stated upper limit would be wasteful and inefficient and could result in hydrodynamic over-loading of the coating system and the final blade, and possibly result in the reintroduction of CD coating lay profile variations and MD streakiness. It is preferable to minimize the work required of the secondary blade 46 to insure that the blade tip exerts a uniform pressure across the entire width of the web. Thus, excess flow rates need to be maintained within acceptable minimum and maximum limits.
Also, the spacing between the blades 44 and 46, and thus the dwell time of the coating on the web between the two blades, must be maintained within acceptable upper and lower limits. The spacing should preferably be from about 4 to about 24 inches to maintain a dwell time in the order of from about 0.003 to about 0.040 seconds at web speeds of 3,000 to 5,000 fpm. This results in providing adequate dwell time for the boundary layer of coating at the surface of the web to become sufficiently immobilized and stabilized to provide for optimum operation of the blade 46 within this boundary layer or zone. Excessive dwell time, with consequent excessive immobilization of the boundary layer, is to be avoided as that would impose excessive operational requirements on the blade 46 and result in a less desirable final coat. In order to achieve a final bone dry coat weight of 5 to 15 pounds per side per ream with a 62% solids coating compostion, the pressure exerted by the tip of the secondary blade 46 on the coated web should preferably be within the range of from about 2 pli to about 9 pli.
When operated under the described conditions, the secondary blade 46 will perform efficiently and effectively to doctor onto the web a very uniform and smooth surfaced coating free of MD streaking.
The improved coating method and coater of the invention, comprised of the non-conventional applicator 42 and the primary and secondary blades 44 and 46, thus cure the problems encountered with predecessor coaters and coating methods, including the conventional SDTA. However, on those occasions when it is desired to pre-coat the web, or to utilize first and second coating compositions having different characteristics and advantages, or to apply an especially heavy weight of coating to the web, it may prove advantageous to have a preliminary coater precede the coater of the invention.
For purposes of carrying out multiple coating processes in a wet on wet relationship, two of the coaters of the invention may be mounted for sequential application of coatings to a web supported on a common backing roll as illustrated schematically in FIG. 2, or a coater of the invention may be preceded by a conventional applicator as illustrated schematically in FIG. 1.
In the apparatus of FIG. 1, just before reaching the bottom dead center position of the roll 10, the roll supported web passes a dip roll applicator 20 having a coating reservior or pan 22 within which a dip roll 24 is rotated to pick up coating composition from the pan and transfer it to the exposed lower surface of the web. As is known in the art, the dip roll 24 is rotated in such a direction that the upper surface thereof moves in the same direction but at a surface speed slower than that of the web. The roller may engage the web, or just kiss the web, or be spaced from the web depending upon the functions to be performed by and the nature of the coating to be applied to the web by the roll 24.
As indicated by the double headed arrow, the dip roll is independently movable toward and away from and adjustable relative to the roll 10 to accommodate threading of the web through the coater, to accommodate selective use of the dip roll, and to accommodate appropriate adjustment of the dip roll relative to the roll supported web.
If desired, the dip roll applicator 20 could be preceded and/or replaced by a puddle or pond coater located on the downwardly moving, incoming side of the roll 10.
As a further and highly advantageous alternative, the dip roll applicator 20 may be followed, as at 30, by pre-metering chamber means of the type disclosed in U.S. Pat. No. 4,963,397 or by jump shear plate means as disclosed in U.S. Pat. No. 4,859,507, the teachings of each of which are incorporated herein by reference. Use at 30 of the apparatus disclosed in either of the U.S. Patents mentioned above will eliminate or minimize the dip roll film split pattern that develops in the coating resulting from operation of the dip roll at web speeds in excess of bout 2,800 fpm, thereby to deliver a more uniformly pre-coated web to the applicator 42 and/or primary blade 44. Excess coating removed from the web by the apparatus 30 and/or overflowing the pan 22 is returned via channel 32 to a source of supply (not shown) for recycling and for recirculation back to the pan 22.
From the foregoing, the mode of operation of the coating apparatus illustrated in FIG. 2 will be apparent to those skilled in the art. In essence, the first coater 40a will apply to the web an even smoother and more consistent pre-coat than can be applied with a dip roll or any other presently known applicator or coater. Also, the capacity for selective use of the blades 44a and 46a, in conjunction with the blades 44b and 46b, provides the facility for subjecting the applied coating to two, three or four zones of shear at the nip between the coated web and respective ones of the four inverted blades, thereby to insure application to the web of very consistent and uniform coatings of very high quality and smoothness, free of MD streaking and other imperfections.
As an alternative, the secondary blade 46a of the first coater 40a could be replaced with the pre-metering chamber means or jump shear plate means 30 previously referred to. Thus, the FIG. 2 apparatus should be understood to comprise a first short dwell applicator 42a, a first doctoring means 44a, a secondary doctoring means 46a or 30, a second short dwell distribution apparatus 42b, a semi-final blade 44b and a final blade 46b, all selectively operable to achieve various paper coating objectives.
In the arrangement illustrated in FIG. 2, the tip of the final blade 46b should preferably engage the roll supported web at or in proximity to the horizontal centerline of the roll on the upwardly moving, outgoing side of the roll, the semi-final blade 44b should engage the web about 30° to 40° upstream from the final blade, the first applicator 42a should be on the upwardly moving side of the roll 10, suitably within about the first 25° downstream from the bottom dead center position of the roll, and the first primary blade 44a should contact the web at about 25° downstream from bottom dead center, i.e., 25° to 35° upstream from the semi-final blade 44b. If used, the secondary doctoring means 46a or 30 should be fitted between the blade 44a and the applicator 42b as best suited to the particular physical environment.
The purpose in utilizing two of the coaters of the invention in sequence on a common backing roll is to facilitate production of very high quality coatings on webs traveling at the highest speeds presently contemplated, i.e., 5,000 fpm.
Simulation studies reveal that web speed dominates the flow of the coating liquid in the application zone 53, whereas fluid rheology does not significantly alter flow characteristics at high web speeds, at least close to the nip between the web and the web blade 44. At very high speeds, a high intensity vortex with counter rotating vortices is developed within the application zone, which generates extreme hydrodynamic instabilities that may be responsible for the difficulty in controlling CD coat weight uniformity. The simulation and the conclusions drawn therefrom would tend to explain the observation of unusual. turbulence in the coating liquid flowing reversely through the orifice gap 56 at web speeds of 4,000 to 5,000 fpm.
The coater of the present invention provides the best means known for eliminating CD caliper variations and MD streaking, and utilization of two of the coaters in sequential order will ensure both a uniform pre-coat and a uniform final coat under conditions such that neither the secondary doctor 46a nor the final blade 46b will be subjected to nonuniform hydrodynamic impulse forces. Thus, the final coating, even at web speeds approaching 5,000 fpm, will fulfill all of the expectations and requirements of the graphic arts and quality printing and publication trades.
The current requirements in such trades for coated papers of the type intended to be produced by practice of the method of the invention with the apparatus of the invention are listed below. In the list of characteristics, "Printsurf" refers to Parker Printsurf printing surface smoothness (the lower the number, the smoother the surface); Paper Gloss is the gloss of the coated paper before printing, as measured at different angles of reflectance; and GIH is the gloss ink hold-out of the coated paper, using red and black commercial sheet offset inks, as measured at different angles of reflectance (a higher number indicating a better result).
______________________________________Paper Web: Merchant grade paper having little or no groundwood with a brightness of 79 and above.Coat Weight: 5 to 15 lbs per side per 3,300 sq ft ream.Appearance: Overall uniformity of coating lay. No film split pattern or MD streakiness. No observable scratches or other imperfections in the coating lay.Printsurf: 1.10 and lower (lower number is smoother)GIH Red 20°: 40-70GIH Black 20°: 20-50Paper Gloss 20°: 15-35GIH Red 75°: 80-100GIH Black 75°: 80-100Paper Gloss 75°: 60-90______________________________________
The foregoing standards have been established with respect to coatings applied to merchant grade webs by means of a DRIB coater, i.e., a dip roll applicator and an inverted trailing blade, operating at speeds up to about 2,500 fpm. At speeds in excess of about 2,500 fpm, a DRIB applied coating will no longer satisfy the "appearance" characteristic above stated, which is one of the most if not the most important of the requirements imposed by the trade.
The coating method and coater of the invention overcome this problem and provide coated papers meeting or exceeding all of the above requirements, and particularly the "appearance" requirement, even when operated at web coating speeds in excess of 3,000 fpm, and on up to 5,000 and more fpm. In addition, coated papers produced in accordance with the invention exhibit significant improvements over their DRIB coated counterparts in terms of significantly reduced blade scratches and significantly improved ink hold-out, gloss, and surface smoothness, all of which are very important characteristics of the coated paper. For example, when coating the felt side of the same paper with the same coating composition at the same coat weight and under comparable conditions, the coating method of the invention produced the following improvements in the coated web:
______________________________________Coat Weight: 12.5 lbs per side per 3,300 sq ft ream Method Without Method With Dip DRIB Dip Roll Pre-Coat Roll Pre-Coat______________________________________Printsurf 0.94 0.93 0.85GIH Red 20° 54 58 64GIH Black 20° 45 50 54Paper Gloss 20° 31 36 35GIH Red 75° 98 99 100GIH Black 75° 95 96 97Paper Gloss 75° 85 88 88______________________________________
Thus, the invention provides significant advantages over the prior art and facilitates the production at ultra high speeds of coated papers fullfilling the exacting demands of the publication trades.
Operational criteria for representative trial runs of the coater of the invention at speeds of 3,000 to 4,000 fpm to produce coated papers that satisfy all of the above requirements and specifications and that are very smooth surfaced and free of MD streaking are as follows:
______________________________________Sample No. 1 2 3 4______________________________________Final Coat Wt (lbs/rm) 5.3 5.3 14.7 15.3Web Basis Wt (lbs/rm) 49.1 51.6 42.3 42.2Web Speed (fpm) 3120 3893 3045 3955Coating Supply (gpm/in) 1.2 1.13 1.55 1.55Primary Blade Pressure (pli) 2.3 2.3 1.5 1.5Primary Blade Metered .321 .385 .413 .487to Web (gpm/in)Primary Blade Metered .00198 .00191 .00261 .00237Film Thickness (in)Final Blade Pressure (pli) 5.5 5.5 2.0 2.6Final Wet Coat on .054 .067 .147 .198Web (gpm/in)Final Wet Coat .000333 .000333 .000929 .000964Film Thickness (in)Excess Coating to Final .267 .318 .267 .289Blade (gpm/in)______________________________________
Operational criteria for representative trial runs of the coater of the present invention preceded by a dip roll applicator 20 (i.e., the coating apparatus of FIG. 1 without the apparatus 30) to produce coated papers free of MD streaking and satisfying all of the requirements of the printing and graphic art trades are as follows:
______________________________________Sample No. 5 6 7 8______________________________________Final Coat Wt (lbs/rm) 5.3 5.8 14.3 14.1Web Basis Wt (lbs/rm) 42.6 42.4 48.6 48.1Web Speed (fpm) 3020 3926 3027 3859Dip Roll Speed (fpm) 450 500 450 500Dip Roll Supply (gpm/in) 2.18 2.46 2.18 2.46Applicator Supply (gpm/in) 1.05 1.05 1.14 1.14Primary Blade Pressure (pli) 2.3 2.3 1.7 2.0Primary Blade Metered .329 .789 .664 .738to Web (gpm/in)Primary Blade Metered .00210 .00387 .00423 .00368Film Thickness (in)Final Blade Pressure (pli) 5.5 5.5 2.7 3.8Final Wet Coat on 0.052 0.074 .141 .178Web (gpm/in)Final Wet Coat .000332 .000363 .000898 .000888Film Thickness (in)Excess Coating to .277 .715 .523 .560Final Blade (gpm/in)______________________________________
All of the above described trials were made on the same laboratory pilot coater; the web was a web offset, merchant grade, free sheet; the coating composition comprised a starch-latex adhesive system with clay at 62% solids and a viscosity of 5200 cps at 20 rpm; the orifice gap 56 was 0.1875 inches from the web; the primary blade was 0.015 inches thick and its angle was 35° to the tangent of the roll 10 at the point of blade tip contact; the secondary blade was also 0.015 inches thick and its angle to the roll tangent was 45°; and the secondary blade 46 was spaced 13.1 inches circumferentially downstream from the primary blade 44. For the wet on wet coatings using the dip roll applicator 20, the surface of the roll 24 was spaced 0.005 inches from the web and the roll was driven at a surface speed between 13 and 15% of the speed of the web. All samples were completely coated without skips or voids. Paper gloss, smoothness and printability improvements were observed. Most importantly, the coated sheets exhibited no streakiness and fullfilled the "appearance" requirements of the trade.
Referring now to FIG. 3, a physical construction for the preferred embodiment of the coater of the invention is illustrated as comprising a short dwell applicator 42, a primary blade 44 and a secondary blade 46 all adjustably mounted on and carried by a common support structure.
The previously described components of the applicator 42 are mounted on and supported by a rigid transverse beam 68 which is mounted for pivotal movement toward and away from the roll 10 by means of a pair of pivot arms 70 which are pivotally mounted on the machine frame (not shown) on opposite sides of the frame outwardly of the opposite ends of the roll 10. The pivot arms 70 are adapted to be moved simultaneously by hydraulic or pneumatic rams or similar means (not shown) to swing the beam 68 and the applicator components supported thereby toward and away from the web supporting roll for shut-down, maintenance and cleaning, to facilitate threading of the web through the coater, and to adjust the position of the applicator relative to the roll supported web. Preferably, adjustable stops 71 are provided on the machine frame for engagement by the arms 70 to facilitate movement of the applicator into properly adjusted relation to the roll.
In the illustrated embodiment of the invention, the primary blade 44 is carried by the beam 68, and the beam 68 is journaled at its opposite ends on the pivot arms 70 for pivotal movement about a pivot axis that is essentially coincident with the tip of the blade 44. An adjusting means, such as a motorized screw jack, indicated partially at 72, is operable to pivot the beam supported elements relative to the arms 70 thereby to vary and adjust the angle of the primary blade 44 relative to the surface of the roll supported coated paper web. Alternatively, the blade 44 could be mounted on its own adjustable supporting structure for independent adjustment relative to the web.
The blade 44 is retained in a blade holder 44c by means of a first pneumatic tube 44d, or other suitable blade clamping means, and is adjustably biased against the roll supported coated web by means of a second pneumatic blade loading tube 44e which is adjustably mounted on the holder 44c. By adjusting the location of the tube 44e and the pressure of the air supplied thereto, the tip of the blade 44 can be pressed against the coated web at various blade tip pressures, as previously described.
As is known in the art, the blading action of a doctor blade on a coated web is a function of blade thickness, angle and loading. In the case of the primary blade 44 of the invention, we have successfully utilized a blade thickness of 0.015 inches and an angle of attack of about 35 degrees. The preferred loading on the primary blade is from about 1 to about 41/2 pounds per lineal inch depending upon the physical characteristics and the amount of the coating to be doctored onto the web.
The secondary blade 46 in the illustrated embodiment of the invention is mounted on and supported by a rigid transverse beam 73 which is pivotally mounted at its opposite ends on a pair of V-shaped brackets 74 located at the two sides of the machine outwardly of the opposite ends of the roll 10, the two brackets 74 being tied together for conjoint movement by a tubular cross tie 75. The brackets 74 are pivoted at 76 to the pivot arms 70 supporting the beam 68, whereby the entire combination of elements comprising the coater can be swung simultaneously toward and away from the roll 10 without disrupting any previously established adjustments of the applicator 42, the primary blade 44 and the secondary blade 46.
An adjusting means, preferably in the form of a hydraulic or pneumatic ram 77, extends between each pivot arm 70 and the associated bracket 74 to adjust the position of the blade 46 relative to the applicator 40 and the roll supported coated web. Adjustable stops 78 are preferably provided for engagement by the brackets 74 to facilitate movement of the blade 46 into its adjusted position relative to the roll 10. Also, an adjusting means 79 extends between and is pivotally connected at its opposite ends to the bracket cross tie 75 and the beam 73 to pivot the beam about a pivot axis that is essentially coincident with the tip of the blade 46, thereby to adjust the angle of the secondary blade 46 relative to the surface of the coated web.
The secondary blade is mounted in its blade holder 61 by a first pneumatic tube 46d, or other clamping means, and is adjustably biased against the surface of the coated web by a second pneumatic blade loading tube 46e.
In practice of the present invention, we have successfully employed a secondary blade having a thickness of 0.015 inches and an angle of attack of about 45 degrees. The preferred loading for the secondary blade is from about 2 to 9 pounds per lineal inch, depending upon the coatweight of the coating to be finally doctored onto the web.
FIG. 4 illustrates how the method and apparatus of the present invention when coating a woodfree 60 pound base sheet, which was first given a prime coat of 11/2 pounds per side and then coated with 81/2 pounds per side and supercalandered, develops a superior and relatively constant paper smoothness of about 1.32 Parker Printsurf (PPS) when coated at web speeds of from 2000 feet per minute (fpm) to 4000 fpm. See Curve A. This paper may be compared to supercalandered prior art dip roll inverted blade coated paper (Curve B) and prior art fountain type coated paper (Curve C) wherein, PPS deteriorates with increasing web speeds. FIG. 5 illustrates how the method and apparatus of the present invention, develops a paper, just described, with considerably higher Gloss (Curve A) that decreases or declines less with increased web speed at which it was coated (having a lower slope in a plot of gloss versus speed) than does similar prior art dip roll inverted blade coated paper (Curve B) or similar prior art fountain coated paper (Curve C). The advantages of the present invention are the paper, after supercalandering, is of a more uniform smoothness and consistent gloss, of say 70, or higher, regardless of what web speed the coating process was carried out. Thus, whether made at 2000, 3000, 4000 or more feet per minute, the smoothness and gloss is much more similar than with these other prior art type coaters, giving the papermaker additional flexibility in operation and yet being able to satisfy customer demands.
With the coater thus physically constructed, the present invention can be practiced with particular facility to attain all of the advantages herein described, and particularly to produce at very high web speeds coated papers having excellent surface characteristics entirely free of MD streaking and other imperfections.
While certain preferred embodiments of the invention have been illustrated and described, it is to be appreciated that various changes, rearrangments and modifications may be made therein without departing from the scope of the invention, as defined by the appended claims.
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A method for coating a web with a coating material by applying a metered coating material onto the web and smoothing the applied coating material evenly onto the web with a flexible predoctoring blade. The coating material is applied to the web by the predoctoring blade in the form of a high velocity laminar flow in advance of the predoctoring blade. The coating mix is fed to a stem part of the flexible blade via an exit channel having a narrow opening. The loading of the flexible blade, acting as a smoothing device, is controlled in a cross direction of the web in order to control the cross directional profile of the applied coating web. The feed velocity of the laminar flow is at least one small m/sec.
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The present invention is directed to a power conservation system for modulated data communications, and more particularly to a power conservation system for transmission systems in which data is modulated over a communications loop from a central office location to a customer premises.
BACKGROUND
Wire loops extending from a telephone company central office to a customer premises are a ubiquitous part of the existing communications infrastructure. These wire loops form a communications network often referred to as the plain old telephone service' (POTS) network. The POTS network originated to support analog voice phone service.
The POTS network currently supports a wide range of communications services in addition to analog voice phone calls. These services include digital data transmissions from facsimile (FAX) machines and computer modems. Voice calls, FAX connections, and computer modem transmissions all operate within the frequency spectrum of traditional POTS calls, thus ensuring compatibility with the existing wire loop infrastructure and allowing transport of these services end-to-end through the POTS phone network. However, the use of POTS-compatible transmission frequencies severely limits the maximum information carrying capacity of the wire loop.
Certain transmission technologies may use carrier frequencies greater than those required for POTS services to exceed the information capacity limits of POTS calls over wire loops. However, since the existing POTS loop infrastructure was not designed for carrying such high frequency signals, severe impediments to such transmission exist. In particular, as a result of electromagnetic coupling among wire loops, electromagnetic noise signals are induced on the loops. This electromagnetic coupling may occur among the large number of loops in the wire bundles that extend from the central office to various customer distribution points.
Noise signals induced on the loops by electromagnetic coupling may not be perceptible on POTS voice calls. However, such signals may significantly interfere with wide-bandwidth modulated data transmissions that use high frequency signals. To reduce interference problems, sophisticated signal processing circuitry, such as digital signal processors (DSPs), are used within modulated data receiver and transmitter units to remove noise, to encode and decode desired signals, and to perform error correction functions.
To minimize the number of wire loops needed to service a customer's premises, POTS signals and modulated data transmission signals may be combined on a single wire loop. To combine POTS and wide-bandwidth modulated data transmission signals, the wide-bandwidth modulated data is transported using frequencies (spectrum) greater than those of POTS services. This spectrum usage allows a POTS service connection to be supported by its traditionally allocated spectrum while simultaneously supporting high frequency modulated data transmission. Thus, current technology permits POTS and high bandwidth data may be carried between customer premise equipment (CPE) and a central office (CO) on a single wire loop. At the central office, the POTS signal frequencies are separated from the high frequency data signal; the POTS signal is then handled by the existing POTS switch and network, while the high frequency spectrum is directed to separate processing components.
Signal processing, transmitting, and receiving circuitry for such high frequency modulated data signals requires a substantial amounts of power, typically up to 5 watts per loop served. For a large central office, potentially serving many thousands of such data connections, this power usage is substantial.
SUMMARY
In general, in one aspect, the invention features a method of conserving power in a terminal unit having a transmitter and receiver for modulated data communication over a communications loop that is shared with voiceband telephone equipment. The method includes monitoring the loop to detect a shut-down condition, reducing power consumption of certain of the electronic circuits in the terminal unit upon detection of a shut-down condition, monitoring the loop with a monitoring circuit to detect a resume signal outside the voiceband frequency range on the loop, and restoring power to the electronic circuits when the resume signal is detected.
Implementations of the invention may include one or more of the following features. The modulated data may be a bit stream including framing information, and a shut-down condition may be indicated by a loss of framing information. The modulated data may include a signaling channel and a shut down condition may be indicated by bits transmitted in the signaling channel. The resume signal may be an AC signal at a frequency above voiceband, such as a 16 kHz AC signal.
In general, in another aspect, the invention features a modulated data transmitting and receiving unit. The unit includes a connector for coupling the unit to a communications loop, circuitry to transmit and receive a modulated data signal in a frequency range above voiceband, and circuitry to detect a resume signal in the frequency range above voiceband and then to initiate a power up sequence for the transmit and receive circuitry.
Implementations of the invention may include one or more of the following features. The connector may be a two-wire connector. The transmit and receive circuitry may include Asymmetric Digital Subscriber Line transmit and receive circuitry. The resume signal detection circuitry may be a 16 kHz frequency detector. The communications loop may be a wireless communications loop. The resume signal may be an AC signal greater than 4 kHz or may be a multi-tone AC signal. The unit may also include a control signal interface to receive a start-up signal, and circuitry to transmit a resume signal upon receipt of the start-up signal.
In general, in another aspect, the invention features a modulated data transmitting and receiving unit. The unit includes a connector for coupling the unit to a communications loop, a control signal interface for receiving a start-up signal, circuitry to transmit and receive a modulated data signal at frequencies above voiceband, and circuitry to transmit a resume signal on the loop upon receipt of a start-up signal on the control signal interface.
Implementations of the invention may include one or more of the following features. The communications loop may a wireless loop. The control signal interface may be a data interface, such as a peripheral component interconnect (PCI) interface. The start-up signal may be indicated by receipt of data on the control signal interface. The control signal interface may be used for the exchange of both the start-up signal and of data between the modulated data transmitting and receiving unit and customer premise equipment.
Among the advantages of the invention are the following. Modulated data signal processing, transmitting, and receiving circuitry can be placed in a low power state when inactive, and then re-energized to resume full power operation as needed. Central office terminals (COTs) and customer premises equipment (CPE) units can exchange shut-down and resume signals without interfering with POTS services on the wire loop. Additionally, either a CPE or a COT unit can initiate both a low power state and resumption to a full power state.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of an ADSL unit in accordance with the invention.
FIG. 2 is a diagram of a central office with a central office terminal (COT) ADSL unit connected by a two-wire loop to a customer premises equipment (CPE) ADSL unit in accordance with the invention.
FIG. 3 is a flowchart of a data exchange between two connected ADSL units in accordance with the invention.
DETAILED DESCRIPTION
Asymmetric Digital Subscriber Line (ADSL) technology is used to transmit wide-bandwidth modulated data over a two-wire loop using high frequency carrier signals. ADSL allows a two-wire loop to simultaneously transport POTS analog voice phone services along with high speed modulated digital data over wire loops of up to 18,000 feet. This simultaneous support of POTS and modulated digital services is provided by transporting POTS services using their traditionally allocated spectrum while transporting modulated digital data using spectrum outside of the POTS range.
FIG. 1 is a block diagram of an ADSL unit. To send and receive modulated digital data, the ADSL unit 100 employs high speed signal processing electronics 111 that includes, for example, digital signal processing (DSP) circuitry. Signal processing electronics 111 eliminate stray electronic noise induced on the two-wire loop 120 and, along with transmit circuitry 112 and receive circuitry 113, are used to send and receive modulated data. In addition, signal processing circuitry 111 may implement error correcting algorithms, such as the Reed-Solomon algorithm, to further reduce data errors that arise during transmission. The signal processing, transmit, and receive functions may be provided by, for example, a Motorola CopperGold chip set or a GlobeSpan Technologies STAR or SLADE chip set. Control circuitry 117 is provided to control operation of the ADSL unit 100, to control power usage by ADSL unit circuitry, and for storage of ADSL unit parameters.
To provision ADSL service, an ADSL unit 100 is located at each end of a wire loop 120. Referring to FIG. 2, an ADSL unit 100 located at the subscriber premises 240 is referred to as a customer premises equipment (CPE) ADSL unit 242. A second ADSL unit 100, typically located at a telephone company central office 230, is known as the central office terminal (COT) unit 232. The CPE unit and the COT unit are connected by a two-wire loop 220 of up to 18,000 feet.
Central office and customer premises equipment connects to the ADSL unit through a data interface 116 (FIG. 1). At the central office end of the loop 230, the data interface of the COT unit 232 is connected to central office data switching equipment 234. At the subscriber end of the loop 240, the data interface of the CPE unit 242 is connected to customer premise equipment such as a personal computer 244.
Data to be transmitted by an ADSL unit is arranged in a structure known as a `frame` prior to being transmitted. A frame is an arrangement of bits including both user data and signaling information required by the ADSL units. When there is nothing to transmit between ADSL units, the user data portion of the frame may be filled with idle packets. Within the ADSL framing structure is a low bit rate signaling channel over which handshaking information can be exchanged between ADSL units. This signaling channel may be used, for example, to test the wire loop transmission path and to send ADSL device status information.
Circuitry within each ADSL unit 232 and 242 is used to remove noise, to perform error correction, to multiplex data, and to transmit and receive data. This is done without interfering with POTS audio and signaling transmissions over the two-wire loop 220, which uses spectrum below 4 kilohertz (kHz). Modulated data from the ADSL units 232 and 242 is transmitted using spectrum above 4 kHz, typically using a range of frequencies of 40 kHz and greater. Signal filters 233 and 243 (known as "splitters") are used to join signals being transmitted from one location, for example, the central office 230, and to separate signals when they are received at the distant location, for example, the customer premises 240.
Within the central office 230, a splitter 233 is used to combine outgoing signals from the POTS switching equipment 231 and the COT ADSL unit 232 for transmission on the loop 220. The splitter 233 also provides signals received on the two-wire loop 220 to both the POTS switching equipment 231 and to the COT ADSL unit 232. Signals to be sent to the POTS switching equipment 231 are filtered by the splitter 233 so as to remove frequencies above voiceband. The resulting filtered signal may be handled by the POTS switch 231 as if it had originated on a traditional analog POTS connection. The signal from the splitter 233 to the COT ADSL unit 232 may contain the full frequency spectrum as it arrives over the wire loop 220 or may be filtered to remove voice band frequencies.
At the customer premises 240, a splitter 243, which may serve as a telephone company network interface (NI) device, is used to combine outgoing signals from customer premises POTS-compatible equipment 241 and the CPE ADSL unit 242 for transmission on the loop 220. The splitter 243 is also used to direct signals received on the two-wire loop 220 to both customer premises POTS equipment 241, such as an analog telephone or a FAX machine, and to the CPE ADSL unit 242.
Signals to be sent to the customer premises POTS equipment 241 are filtered to remove frequencies above voice band. The resulting filtered signal may be handled by the customer premises POTS equipment 241 as if it had originated on a traditional analog POTS connection. The signal from the splitter 243 to the CPE ADSL unit 242 may contain the full frequency spectrum as it arrives over the wire loop 220 or it may be filtered to remove voiceband frequencies. The CPE ADSL unit 242 may be incorporated in, for example, an ADSL modem connected to a personal computer 244 that is programmed to send and receive over the ADSL connection. Circuitry to handle POTS and ADSL data functions may be combined within a single physical device handling signal splitting and filtering, POTS call processing and modulated data processing, transmitting, and receiving. Alternatively, these functions may be achieved using a number of physically separate devices.
Prior to initiating transport of modulated data over the loop 220, signals are exchanged over the loop 220 between the COT unit 232 and the CPE unit 242 to adapt the ADSL units to the electronic characteristics of the particular wire loop 220. For example, loop loss characteristics, which are a function of loop length, wire gauge, wire composition, and other factors, are exchanged. This exchange of information is often referred to as handshaking. Once handshaking is completed, transmission of user data may begin.
To reduce power requirements, the ADSL units 232 and 242 may enter low power mode when user data transmission is complete. Either unit may initiate the low power mode. If, for example, the CPE unit 242 initiates low power mode, it does so by sending a shut-down signal to the COT unit 232. This shut-down signal may be conveyed in the ADSL low bit rate signaling channel; alternatively, an out-of-band signal on the loop may be used, for example, a 16 kHz AC signal. Still another alternative is for the CPE unit to stop sending ADSL framing information (such as would happen if the CPE unit were powered down).
Upon receipt of the shut-down signal, the COT unit 232 optionally stores in memory 117 characteristics of the loop 220 that were determined by CPE to COT handshaking. Likewise, upon sending the shut-down signal, the CPE unit 242 may also optionally store the loop characteristics that it obtained through CPE to COT handshaking. Storing loop characteristics enables rapid resumption of user data transmission when the units are returned to full power mode. Each unit 232 and 242 may then enter low-power mode by shutting off the now unnecessary sections of signal processing 111, transmitting 112, and receiving 113 circuitry. The loop 220 will then be in an inactive state. Circuitry 115 to detect the resume signal must remain capable of signal detection during low power operation. If the COT unit 232 were to initiate low power mode, signals would be exchanged with the CPE unit 242 in a like fashion.
In alternative embodiments, both CPE 242 and COT 232 units may be capable of reduced power operation. Alternatively, only the COT 232 unit may reduce its power consumption, or only the CPE unit 242 may reduce its power consumption. If only the COT unit 232 is to reduce its power consumption, the COT unit 232 will not require resume signal generation 114 circuitry, nor will the CPE unit 242 require resume signal detection circuitry 115. Similarly, if only the CPE unit 242 is to reduce power consumption, the CPE unit 242 will not require resume signal generation 114 circuitry nor will the COT unit 232 require resume signal detection circuitry. Thus, the particular circuit components that can be placed in a low power mode may vary among differing brands, models, and versions of ADSL units.
To return a unit that is in low power mode to full power operation, a resume signal is sent to the unit. In one embodiment, a COT ADSL unit resumes full power operation upon receipt of a 16 kHz AC signal that is sent over the wire loop by a CPE ADSL unit. This resume signal may be detected by the COT unit using a 16 kHz AC signal detector 115 that employs conventional frequency detection techniques. This detector 115 remains operative when the unit 232 is in low-power mode. If the CPE unit 242 is capable of reduced power operation, a resume signal sent from the COT unit 232 to the CPE unit 242 would be similarly received at the customer premises and detected by the CPE unit 242.
Upon receipt of the resume signal, the receiving ADSL unit returns the signal processing 111, transmitting 112, and receiving 113 circuitry to full power mode. If loop transmission characteristics had been stored, these parameters are retrieved from memory 117 and used to enable data transmission to resume quickly by reducing the time needed to determine loop transmission characteristics. After resumption of full power mode, additional handshaking between ADSL units 232 and 242 may occur. Upon reaching a fully operational state, transmission of user data may resume.
Referring to FIGS. 2 and 3, one exemplary application of the invention is to reduce power requirements needed to maintain a link between a personal computer (PC) 244 and a remote data source 250. The remote data source 250 may be, for example, an Internet service provider (ISP) or an online service provider (OSP). In an exemplary configuration, a CPE ADSL unit 242 is connected by a digital interface 247 to a personal computer 244 programmed to send and receive data over the ADSL unit 242. The CPE ADSL unit 242 may be incorporated in an ADSL modem that is installed in, or connected to, the PC 244. The CPE ADSL unit 242 is connected by a wire loop 220 to a COT ADSL unit 232 at a central office 230 at which a link to the remote data source 250 exists.
In the exemplary configuration, the wire loop 220 is initially inactive, thus preventing information flow between the CPE 242 and COT 232 ADSL units. To return the loop 220 to an active state, a start-up signal is sent to the CPE ADSL unit (step 301). The start-up signal is, for example, a command sent over the digital interface 247 from a device driver or other program module running in the PC 244 or may be represented by power to the CPE ADSL unit being turned on. Upon receipt of the start-up signal, the CPE ADSL unit may restore saved loop characteristic parameters (step 302). The CPE ADSL unit then transmits a 16 kHz resume signal on the loop (step 303) The resume signal is subsequently detected by loop monitoring circuitry in the COT unit (step 304). If the COT unit is in a low power state, it will return to full power operation upon detection of the resume signal from the CPE unit, this may include restoring loop characteristic parameters (step 305). If the COT unit was not in a low power state, the resume signal may be ignored by the COT unit. CPE and COT ADSL units may then exchange handshaking information to establish reliable data communication between the units (step 306). Handshaking information may be required where, for example, loop characteristics have changed due, for example, to temperature-dependent changes in loop resistance.
Handshaking information may also be exchanged for other device initialization purposes.
Once reliable data transmission from the CPE to the COT ADSL units is established, information may be exchanged over the established data path (step 307). Referring to FIG. 2, the personal computer 244 may use the data path between ADSL units to communicate with a remote data source by sending information over a digital interface 247 to the CPE ADSL unit 242. This digital interface may be an industry standard computer interface such as a small computer systems interface (SCSI), an Ethernet interface, or a peripheral component interconnect (PCI) interface, or other industry standard or vendor proprietary interfaces allowing two-way data exchange. Information from the PC to the CPE unit may include both user data and signaling information to control CPE ADSL unit operation or, by relaying such signaling over an ADSL to ADSL unit signaling channel, to control COT ADSL unit operation. User data provided to the CPE unit by the PC is transmitted to the COT unit over the established CPE to COT data transmission path.
Data received at the COT unit may be converted to a data signal format compatible with standard telephone company switching equipment, for example, a 1.544 million bits per second (Mbps) T1 data signal, or to asynchronous transfer mode (ATM) cells over an optical carrier level 3 (OC-3) synchronous optical network (SONET) interface. The received data, now in a central office equipment compatible format, may be provided over a standard telephony interface 236 to telephone company high speed data switching equipment 234, such as a digital cross connect switch or multiplexing equipment to a second interface 251 that connects to a remote data source 250. Alternatively, the data may flow from the COT ADSL unit 232 directly to the remote data source 250 without handling by intermediary switching equipment 234. Two way data transfers between the remote data source 250 and the PC 244 may then take place over the resulting path from PC 244 to CPE unit 242 to COT unit 232 to switching equipment 234 to remote data resource 250.
Referring again to FIG. 3, the COT unit may be returned to low power mode by sending a shut-down signal from the CPE unit to the COT unit (step 308). The shut-down signal may be an expressly transmitted signal or may be inferred. For example, the shut down signal may be expressly sent as a series of signaling bits transmitted between the CPE and COT ADSL units. Alternatively, if the PC and COT ADSL unit are shut off, a shut-down signal may be inferred from the loss of transmitted framing information between the CPE unit and the COT unit. The shut-down signal is subsequently detected by monitoring circuitry in the COT ADSL unit (step 309). Upon detecting a shut-down signal, the COT unit may save loop characteristics (step 310) and enter low power mode by reducing power to now unnecessary circuitry (step 311). The described procedure 300 may be repeated to resume data transmission. Essentially the same sequence may occur to reduce power at a CPE ADSL unit 242. A CPE ADSL unit may enter a low power mode when, for example, a preset or programmed period of time passes without any user activity on the data path or an appropriate signal is sent from the COT ADSL unit.
Other embodiments are within the scope of the following claims. For example, while the invention has been described in the context of ADSL units providing an asymmetric data channel, the invention may be applied to other terminal units wherein voice band services share a loop with modulated data transmission, such as in Symmetric Digital Subscriber Line (SDSL) and Rate Adaptive Digital Subscriber Line (RADSL) terminal units. Similarly, while systems with two-wire loops have been described, the invention may be used in systems including wireless loops and loop segments. Wakeup signals may include multi tone signals and other signals outside the POTS spectrum. Terminal unit circuitry may include digital circuitry, analog circuitry, software, firmware, or a combination of these elements. The scope of the invention should be limited only as set forth in the claims that follow.
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Methods and apparatus for conserving power in terminal units that transmit and receive modulated data over a communications loop that is shared with voiceband telephone equipment are disclosed. The methods include monitoring the loop to detect a shut-down condition and reducing power consumption of certain of the electronic circuits in the terminal unit upon detection of a shut-down condition. The methods also include monitoring the loop with a monitoring circuit to detect a resume signal outside the voiceband frequency range on the loop and restoring power to the electronic circuits when the resume signal is detected. The apparatuses include a modulated data transmitting and receiving unit having a connector for coupling the unit to a communications loop, circuitry to transmit and receive a modulated data signal in a frequency range above voiceband, and circuitry to detect a resume signal in the frequency range above voiceband and then to initiate a power up sequence for the transmit and receive circuitry.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a Continuation of U.S. application Ser. No. 09/274,286 filed Mar. 22, 1999 now U.S. Pat. No. 6,273,947.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to methods of preparing a compound semiconductor crystal and to the compound semiconductor crystals prepared thereby, and particularly to methods of preparing a carbon-containing, compound semiconductor crystal and compound semiconductor crystals obtained thereby.
2. Description of the Background Art
It has been conventionally well known that as for an LEC method using a stainless chamber there is a correlation between the CO gas concentration provided in the chamber and the carbon concentration of a GaAs crystal in a high-pressure Ar gas ambient.
FIG. 3 is a graph of carbon concentration in a GaAs crystal versus CO gas concentration in a LEC furnace found in Advanced Electronics Series I-4 Bulk Crystal Growth Technology, Keigo Hoshikawa, BAIFUKAN, p.184, Fig. 7.22. FIG. 3 shows that carbon concentration in a GaAs crystal and CO gas content in the LEC furnace are correlated by a straight line. In the LEC method, the correlation represented in the graph is applied to the adjustment of carbon concentration in a GaAs crystal. The carbon concentration in a GaAs crystal can be controlled by adjusting the CO gas content in the ambient gas using a CO gas cylinder and an Ar gas cylinder for dilution connected to the stainless chamber.
FIG. 4 shows an exemplary GaAs crystal growth equipment for the LEC method disclosed in Japanese Patent Laying-Open No. 1-239089. Referring to FIG. 4 , Japanese Patent Laying-Open No. 1-239089 discloses a method of preparing a single crystal of compound semiconductor by placing in a predetermined gas ambient a raw-material housing portion housing a raw-material melt, detecting at least the concentration of one of H 2 , O 2 , CO 2 and CO corresponding to components of the ambient gas, and controlling the detected concentration of a component at a predetermined value to keep over the entirety of an ingot a predetermined concentration of a residual impurity mixed into a resulting single crystal.
This method can, however, not be applied in preparing a compound semiconductor crystal in a gas-impermeable airtight vessel incapable of supplying a gas from outside the airtight vessel, such as a quartz ampoule.
Japanese Patent Laying-Open No. 3-122097 discloses a method of preparing a GaAs crystal in a quartz ampoule wherein a carbon source is arranged internal to the ampoule and external to a crucible in fluid communication with a polycrystalline compound provided as a raw material to allow the GaAs crystal to be doped with carbon. “Fluid communication” means a free flow of vapor and heat between the inside and outside of the crucible which allows carbon to be transferred into the crucible and thus to a melt. In accordance with the method, a carbon disk is arranged on an opening of a cap. It discloses that the ingots of various doped levels can be provided by varying the amount of carbon arranged external to the opening and/or the crucible.
With this method, however, a large amount of carbon source is placed above the melt. Thus fine powder of carbon falls thereon and can thus vary the carbon concentration thereof. Particularly, the controllability can be poor at a slight carbon concentration corresponding to a level of 0.1×10 15 cm −3 to 2×10 15 cm −3 .
Japanese Patent Laying-Open No. 64-79087 discloses a method of preparing a single crystal of GaAs doped with carbon to reduce dislocation, using a reactor or a boat for crystal growth at least partially formed of carbon. It discloses that when a graphite boat is used, a part of the carbon boat changes into a gas (CO or CO 2 ) due to oxygen derived from a small amount of As 2 O 3 , Ga 2 O or the like remaining in the quartz reactor and the gas is thus added to the single crystal of GaAs in synthesis reaction or in single-crystal growth.
In accordance with this method, however, it is difficult to control the carbon concentration in the crystal due to the difficulty of controlling the amount of As 2 O 3 , Ga 2 O or the like remaining in the quartz reactor. In particular, the controllability can be poor at a slight carbon concentration corresponding to a level of 0.1×10 15 cm −3 to 2×10 15 cm −3 .
Japanese Patent Laying-Open No. 2-48496 discloses a method of preparing a Cr-doped, semi-insulating GaAs crystal wherein a quartz boat or a quartz crucible is used to grow the crystal under the existence of nitrogen oxide or carbon oxide. It discloses that when a GaAs crystal is grown under the existence of nitrogen oxide or carbon oxide, the oxide serves as an oxygen doping source to reduce the Si concentration of the grown crystal so that a semi-insulating crystal is reliably provided.
However, this method contemplates control of oxygen concentration and does not describe control of carbon concentration.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a method of preparing a compound semiconductor crystal allowing the compound semiconductor crystal to be doped with carbon in high reproducibility, and a compound semiconductor crystal prepared thereby.
In one aspect of the present invention, a method of preparing a compound semiconductor crystal includes the steps of sealing carbon oxide gas of a predetermined partial pressure and a compound semiconductor provided as a raw material in a gas-impermeable airtight vessel, increasing the temperature of the airtight vessel to melt the compound semiconductor material sealed in the airtight vessel, and thereafter decreasing the temperature of the airtight vessel to solidify the melted compound semiconductor material to grow a compound semiconductor crystal containing a predetermined amount of carbon.
The carbon oxide gas includes at least one type of gas selected from the group consisting of CO gas and CO 2 gas.
In growing the crystal, preferably the melted compound semiconductor material is at least partially kept in contact with boron oxide (B 2 O 3 ).
In growing the crystal, more preferably the melted compound semiconductor material has its upper surface entirely covered with boron oxide (B 2 O 3 ).
Preferably, the boron oxide (B 2 O 3 ) has a water content of no more than 300 ppm, more preferably no more than 100 ppm.
Preferably, variation of the water content of the boron oxide (B 2 O 3 ) is controlled to fall within a range from +20% to −20%.
In accordance with the present invention, the carbon oxide gas sealed in the airtight vessel preferably has a partial pressure of 0.1 to 100 Torr at 25° C.
In accordance with the present invention, carbon oxide gas is preferably sealed in an airtight vessel according to an expression:
C CARBON =α×P 0.5 (1),
wherein C CARBON (cm −3 ) represents carbon concentration in a compound semiconductor crystal, P (Torr) represents partial pressure of the carbon oxide gas, and α represents any coefficient.
In expression (1) coefficient α preferably ranges from 0.25×10 15 to 4×10 15 cm −3 /Torr, more preferably 0.5×10 15 to 2×10 15 cm −3 /Torr.
In accordance with the present invention, preferably the step of subjecting the airtight vessel to a vacuum heat treatment is also provided before the step of sealing carbon oxide gas in the airtight vessel.
The vacuum heat treatment is preferably provided at a temperature of no more than 350° C.
In accordance with the present invention, at least the internal wall of the airtight vessel and at least the outer surface of the contents of the airtight vessel other than the compound semiconductor material and the boron oxide are preferably formed from a material which does not contain carbon.
The material which does not contain carbon includes at least one material selected from the group consisting, e.g., of quartz, silicon nitride, boron nitride, pyrolytic boron nitride and alumina.
In accordance with the present invention, the gas-impermeable airtight vessel can at least partially be formed from quartz.
Preferably, the portion formed from quartz has a thickness of no less than 1.5 mm.
In growing the crystal, preferably the portion formed from quartz is controlled to have a temperature of at most 1270° C.
In accordance with the present invention, in growing the crystal a space behind a raw-material melt of melted compound preferably has its most heated portion and its least heated portion with a temperature difference of no more than 300° C. therebetween.
In accordance with the present invention, the space behind the raw-material melt is preferably larger, more preferably no less than twice larger in volume than the space on the side of the raw-material melt.
A method of preparing a compound semiconductor crystal in accordance with the present invention is applicable to preparing a compound semiconductor crystal of GaAs.
In another aspect, the present invention provides a compound semiconductor crystal prepared in accordance with the above-described method of preparing a compound semiconductor crystal, having a carbon concentration of 0.1×10 15 cm −3 to 20×10 15 cm −3 .
In accordance with the present invention, the compound semiconductor includes GaAs.
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 shows preparation of a GaAs crystal as one example of a method of preparing a compound semiconductor crystal in accordance with the present invention.
FIG. 2 shows a position of a sample for FTIR measurement in a crystal.
FIG. 3 is a graph of carbon concentration in a GaAs crystal versus CO gas concentration in a conventional LEC furnace.
FIG. 4 shows one example of conventional GaAs crystal growth equipment for the LEC method.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is based on a method of preparing a compound semiconductor crystal in a sealed system (a system incapable of supplying a gas from outside an airtight vessel) using a gas-impermeable airtight vessel.
In accordance with the present invention, carbon oxide gas of a predetermined partial pressure as well as a compound semiconductor provided as a raw material are sealed in a gas-impermeable airtight vessel, the temperature of the airtight vessel is increased to melt the compound semiconductor material and the temperature of the airtight vessel is then decreased to solidify the melted compound semiconductor material to grow a compound semiconductor crystal to thereby allow the compound semiconductor crystal to be doped with carbon with high reproducibility.
As the carbon oxide gas, a stable CO or CO 2 gas can be used to allow the crystal to be doped with carbon in particularly high reproducibility.
In growing the crystal, preferably at least a portion of the melt of the compound semiconductor material can be kept in contact with boron oxide (B 2 O 3 ) and more preferably the upper surface of the melt can be entirely covered with boron oxide (B 2 O 3 ) to prevent other elements of impurities from being introduced into the melt so as to further enhance the reproducibility of the carbon concentration of the crystal.
To reduce an influence of the water contained in B 2 O 3 to control the carbon concentration of the crystal in high reproducibility, B 2 O 3 preferably has a water content of no more than 300 ppm, more preferably no more than 100 ppm. To reduce an influence of variation of the water content of B 2 O 3 to control the carbon concentration of the crystal in high reproducibility, the variation of the water content of B 2 O 3 is preferably controlled to fall within a range from +20% to −20%.
To obtain a practical carbon concentration for a compound semiconductor crystal, i.e., 0.1×10 15 cm −3 to 20×10 15 cm −3 , carbon oxide gas requires a partial pressure of 0.1 to 100 Torr at 25° C., substantially establishing the relation: (carbon concentration in a compound semiconductor crystal)=α×(partial pressure of carbon oxide gas) 0.5 , wherein α represents any coefficient and is preferably 0.25×10 15 to 4×10 15 cm −3 /Torr, more preferably 0.5×10 15 to 2×10 15 cm −3 /Torr.
Conventionally in the prior art, the ambient gas has been represented or quantified by its concentration. For example, an ambient gas for GaAs crystal growth typically has a pressure of 1 to 30 atm. When an ambient gas of 1 atm and an ambient gas of 30 atm which have the same gas concentration are converted into terms of partial pressure, the partial pressure of the latter is 30 times larger than that of the former.
The invention of the present invention have found that in a method of preparing a compound semiconductor crystal in a sealed system (a system incapable of supplying a gas from outside an airtight vessel) using a gas-impermeable airtight vessel, the carbon concentration in the crystal is correlated to the partial pressure of the carbon oxide gas sealed in the airtight vessel rather than the concentration of the carbon oxide gas sealed in the airtight vessel.
Herein the carbon oxide gas sealed in the airtight vessel is represented in the partial pressure at 25° C., since the partial pressure of the carbon oxide gas increases as the temperature of the airtight vessel is increased in growing a crystal. Since a GaAs crystal has a melting point of approximately 1238° C., the partial pressure of the carbon oxide gas sealed at a room temperature (of 25° C.) is considered to be increased by approximately five times during the crystal growth.
While in accordance with the present invention, carbon oxide gas having a predetermined partial pressure is sealed in an airtight vessel, carbon oxide gas may be sealed together with another gas, which can include inert gases, such as helium, neon, argon, krypton, xenon, and nitride gas. When carbon oxide gas is only sealed, it has a concentration of 100%. When carbon oxide gas is sealed, e.g., together with any of the above gases of 50%, the carbon oxide gas has a concentration of 50%. It should be noted, however, that if carbon oxide gas is thus sealed together with any of the above gases, the expression: (carbon concentration in a compound semiconductor crystal)=α×(partial pressure of carbon oxide gas) 0.5 is sufficiently satisfied by the coefficient α preferably having the value of 0.25×10 15 to 4×10 15 cm −3 /Torr, more preferably 0.5×10 15 to 2×10 15 cm −3 /Torr.
Removal of water absorbed in the airtight vessel further enhances the reproducibility of the carbon concentration in the crystal. Accordingly it is preferable to apply a vacuum heat treatment to the airtight vessel before it is sealed. The vacuum heat treatment applied immediately before the vessel is sealed is applied preferably at no more than 350° C., at which temperature B 2 O 3 does not soften or deform.
To control the carbon concentration of the crystal in high reproducibility, at least the internal wall of the airtight vessel and at least the outer surface of the contents of the vessel other than the compound semiconductor as a raw material and boron oxide are preferably formed from a material qhich does not contain carbon, so that further generation of carbon oxide gas can be prevented in the vessel. More specifically, the airtight vessel is preferably formed from a material which does not contain carbon, or the vessel preferably has its internal wall coated with a material which does not contain carbon. It is also preferable that the contents of the airtight vessel other than the compound semiconductor material and boron oxide be formed from a material which does not contain carbon or that the contents have the outer surface coated with a material which does not contain carbon. The material which does not contain carbon is preferably quartz, silicon nitride, boron nitride, pyrolytic boron nitride or alumina.
Furthermore, the gas-impermeable airtight vessel of the present invention can at least partially be formed from quartz, since quartz has superior airtightness and hardly reacts with elements forming the compound semiconductor or carbon oxide gas.
In accordance with the present invention, carbon oxide gas having a predetermined partial pressure is sealed in a gas-impermeable airtight vessel. However, when the airtight vessel is deformed and its internal volume is changed, the partial pressure of the sealed carbon oxide gas is changed and the carbon concentration of the resulting compound semiconductor crystal will deviate from a targeted carbon concentration.
The strength of quartz is reduced at high temperature and is significantly reduced at a temperature at which a GaAs crystal is grown, i.e., 1238° C. If a gas-impermeable airtight vessel is at least partially formed from quartz, the difference between the pressure internal to the vessel and that external to vessel deforms the quartz portion of the vessel and thus changes the internal volume of the vessel. The inventors of the present invention have found that as the vessel's quartz portion is increased in thickness, deformation of the quartz portion is reduced at high temperatures and variation in the vessel's internal volume is thus reduced. The inventors have also found that the quartz portion of the vessel preferably has a thickness of no less than 1.5 mm, more preferably no less than 2.0 mm, still more preferably no less than 2.5 mm.
The inventors have also found that as temperature is decreased, deformation of quartz is reduced and variation in the vessel's internal volume is reduced. The inventors have also found that the quartz portion of the vessel preferably has a temperature of at most 1270° C., more preferably at most 1260° C., further still more preferably at most 1250° C.
In accordance with the present invention, carbon oxide gas of a predetermined partial pressure is sealed in a gas-impermeable airtight vessel. When the temperature of the airtight vessel varies, however, the partial pressure of the sealed carbon oxide gas changes and the carbon concentration of the resulting compound semiconductor crystal thus deviates from a targeted carbon concentration.
In particular, the hollow gas-filled space on the side of the raw-material melt, more specifically, the space between the crucible 5 and the ampoule 8 located below the interface (labeled A in FIG. 1 ) of raw-material melt 2 and boron oxide 4 , i.e., the space on the side of the seed crystal has its temperature reduced as crystal growth proceeds. When this hollow space on the side of the raw-material melt is large in volume, the average temperature and hence partial pressure of the carbon oxide gas in the airtight vessel are reduced significantly.
In contrast, the temperature of the hollow gas-filled space behind the raw-material melt, i.e., the hollow gas-filled space within the ampoule 8 located above interface A can be controlled regardless of crystal growth. Thus, controlling the temperature of this space behind the raw-material melt, can prevent reduction of the average temperature of the carbon oxide gas in the airtight vessel and reduce reduction of the partial pressure of the carbon oxide gas in the vessel. Reducing the temperature difference between the most and least heated portions of the space behind the raw-material melt can reduce reduction of the partial pressure of the carbon oxide gas in the vessel. The temperature difference between the most and least heated potions of the space behind the melt is preferably no more than 300° C., more preferably no more than 200° C., still more preferably no more than 100° C.
When the hollow gas-filled space behind the raw-material melt is larger in volume than the hollow gas-filled space on the side of the raw-material melt, this can further reduce the reduction of the partial pressure of the carbon oxide gas in the vessel that is caused when the average temperature of the gas in the vessel is reduced. The space behind the raw-material melt is preferably no less than twice, more preferably no less than three times, still more preferably no less than four times larger in volume than that on the side of the raw-material melt.
Furthermore, the method of the present invention is particularly applicable to preparation of GaAs crystal.
Hereinafter, an example of actual preparation of a GaAs crystal in accordance with the present invention will now be described in detail.
FIG. 1 shows an exemplary method of preparing a compound semiconductor crystal in accordance with the present invention, using a gas-impermeable airtight vessel formed from quartz (referred to as a “quartz ampoule” hereinafter) to prepare a GaAs crystal.
Referring to FIG. 1 , a GaAs seed crystal 3 of orientation <100>, 5 kg of GaAs 2 as a raw material, and 50 g of boron oxide 4 (referred to as “B 2 O 3 ” hereinafter) with a water content of 70 ppm were initially placed in a crucible 5 formed from pyrolytic boron nitride (referred to as “pBN” hereinafter) and having an inner diameter of 80 mm and also having a cylindrical portion of approximately 30 cm in length, and crucible 5 was housed in a quartz ampoule 8 of 2.5 mm thick. The space behind the raw-material melt placed in quartz ampoule 8 , i.e., that located above the interface denoted by arrow A in FIG. 1 was adapted to be four times larger in volume than the space on the side of the raw-material melt, i.e., that located below interface A.
Quartz ampoule 8 has vacuumed to 1×10 −6 Torr and also heated to 300° C. to remove water adsorbed on the internal wall of ampoule 8 and the raw material. Then, CO 2 gas 7 of 3 Torr was introduced and sealed in ampoule 8 . Ampoule 8 was mounted on a support 9 and thus set internal to a vertical heater 6 provided in a chamber 10 , and the temperature of heater 6 was increased to melt GaAs material 2 and an upper portion of seed crystal 3 .
Then the temperature profile of the heater was adjusted to decrease the temperature from the side of the seed crystal 3 and the entirety of raw-material melt 2 was thus solidified to grow a crystal. In the crystal growth, the highest temperature of ampoule 8 was also controlled not to exceed 1250°. Furthermore, the temperature of an upper portion of ampoule 8 was controlled so that the space located behind the raw-material melt, i.e., that located above interface A shown in FIG. 1 had its most heated portion and its least heated portion with a temperature difference of no more than 100° C. therebetween.
The temperature was reduced to a room temperature and quartz ampoule 8 was then cut and opened to separate a GaAs crystal from crucible 5 .
The resulting GaAs crystal had a diameter of 80 mm, and the portion having the diameter of 80 mm was approximately 18 cm long. A sample of 5 mm thick for measurement of carbon concentration was cut out at the position of a shoulder of the crystal (fraction solidified: g of 0.1). FIG. 2 shows the position of the shoulder of the crystal from which the sample was cut out. Fourier Transform Infrared Spectroscopy (FTIR) was used to measure the concentration of the carbon substituted at an arsenic site (referred to as “C As ” hereinafter). The measured C As concentration was 2.1×10 15 cm −3 .
The C As concentration in the crystal grown under a different partial pressure of sealed CO 2 was similarly measured. The measured results are provided in Table 1.
TABLE 1
Partial pressure of sealed CO 2 gas and
C As concentration in GaAs crystal
Partial pressure of sealed CO 2 gas
C As concentration in GaAs crystal
(Torr)
(cm −3 )
0.5
0.8 × 10 15
3.0(embodiment)
2.1 × 10 15
4.5
2.7 × 10 15
6.0
3.1 × 10 15
10.0
4.0 × 10 15
30.0
6.5 × 10 15
60.0
10.0 × 10 15
100.0
13.2 × 10 15
It has been found from the results presented in Table 1 that the relation: (carbon concentration in a compound semiconductor crystal)=α×(partial pressure of carbon oxide gas) 0.5 can be substantially established, wherein a≈1.25×10 15 cm −3 /Torr, under the conditions of the first embodiment.
As a result of experimentally growing a crystal under various conditions, it has been revealed that to obtain a value of a practical carbon concentration in a compound semiconductor crystal, i.e., 0.1×10 15 to 20×10 15 cm −3 , a preferable partial pressure of carbon oxide gas is 0.1 to 100 Torr at 25° C., substantially establishing the relation: (carbon concentration in a compound semiconductor crystal)=α×(partial pressure of carbon oxide gas) 0.5 and that coefficient α preferably ranges from 0.25×10 15 to 4×10 15 cm −3 /Torr, more preferably 0.5×10 15 to 2×10 15 cm −3 /Torr 0.5 , since the coefficient can vary with the conditions of the experiment carried out.
It has also been found as a result of an experiment using B 2 O 3 with its water content varied from 30 to 1000 ppm that the carbon concentration in the crystal can be controlled in higher reproducibility when the water content of B 2 O 3 is lower and has less variation. Satisfactory reproducibility of the carbon concentration in crystal is achieved when the water content of B 2 O 3 is no more than 300 ppm, particularly no more than 100 ppm and the variation of the water content of B 2 O 3 is controlled to fall within a range from +20% to −20%. With CO 2 gas replaced with CO gas, a similar result has also been obtained in a similar manner.
Thus, the present invention can provide a method of preparing a compound semiconductor crystal in a sealed system (a system incapable of supplying a gas from outside an airtight vessel) using a gas-impermeable airtight vessel to allow the compound semiconductor crystal to be doped with carbon in high reproducibility.
Furthermore, carbon oxide gas of a predetermined partial pressure sealed in the gas-impermeable airtight vessel together with compound semiconductor provided as a raw material allows a compound semiconductor crystal with a desired carbon concentration and hence with a desired electrical characteristic to be prepared in high reproducibility, since the electrical characteristic of the compound semiconductor crystal depends on the carbon concentration of the crystal.
Thus the present invention can provide satisfactory crystal yield.
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.
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A method of preparing a compound semiconductor crystal is able to dope the crystal with carbon with high reproducibility. The method includes the steps of sealing a carbon oxide gas of a predetermined partial pressure and a compound semiconductor material in a gas-impermeable airtight vessel, increasing the temperature of the vessel to melt the compound semiconductor material sealed in the vessel, and then decreasing the temperature of the vessel to solidify the melted compound semiconductor material to grow a compound semiconductor crystal containing a predetermined amount of carbon. With this method, a compound semiconductor crystal with a carbon concentration of 0.1×10 15 cm −3 to 20×10 15 cm −3 is prepared with high reproducibility.
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STATEMENT REGARDING SEQUENCE LISTING
The Sequence Listing associated with this application is provided in twxt format in Lieu of a paper copy, and is hereby incorporated by reference into the specification. The name of The text file containing the Sequence Listing is 430192 — 401USPC_SEQUENCE_LISTING.txt. The text file is 2.3 KB, was created on Sep. 26, 2013, and is being Submitted electronically via EFS-Web.
FIELD OF INVENTION
The present invention relates to the biological, physiological, immunological and pharmacological effect of placental protein 13 (PP-13), its fractions, derivatives and gene expressions. In particular, the invention relates to methods for preventing and/or treating preeclampsia of pregnant female mammal, especially pregnant women. This facilitates and makes possible early clinical intervention when a preeclamptic condition or the risk to develop it is determined with the purpose to cure, reverse or reduce the severity of the pathological disease conditions associated with the disorder.
BACKGROUND OF THE INVENTION
Preeclampsia is a syndrome defined by hypertension and proteinuria developed after twenty (20) weeks of gestation that also may be associated with myriad other signs and symptoms, such as oedema, visual disturbances, elevated liver enzyme, hemolysis, low platelets, headaches, and epigastric pain [ 1 ]. One sub-form of the disease, denoted HELLP, standing for hemolysis, elevated enzyme liver and low platelets, can occur with or without hypertension, and the term preeclampsia include this sub-form throughout this document. This disease complicates 3-7% of all pregnancies and is a multisystem maternal disorder that is the most common cause of death for both children and mothers during pregnancy. While the clinical manifestations appear from week 20, the underlying mechanisms may begin as early as at the time of implantation. As the disease progresses the disease may develop into its severe type called eclampsia, caused by angiospasmus in the brain and brain oedema that may result in severe epileptic seizures, stroke and death.
The etiology for preeclampsia is unknown but it is believed that during placentation, the invasion by the placental cells, the trophoblasts, into the uterus wall layer of the spiral arteries appears to be incomplete [ 2 - 3 ] and the severity of hypertension may be related to the degree of trophoblastic invasion [ 4 ]. Vasoconstriction and elevated resistance to blood flow follows as a consequence. The etiology is also described as decreased placental perfusion (or placental insufficiency), in combination with oxidative stress that causes general endothelial cell damage within the placenta which may result in endothelial inflammation, affecting the maternal vascular system and the vascularization of the kidneys.
About one third of cases develop in the first pregnancies. Other risk factors include multifetal gestations, conceiving through in-vitro fertilization, particularly oocyte donation, preeclampsia and hypertension disorders in a previous pregnancy, family history of preeclampsia, chronic hypertension, pregestational diabetes, vascular and connective tissue disease, nephropathy, antiphospholipid antibody syndrome, systemic lupus erythematosus (SLE), obesity, age 35 years and older, teenagers and African-American race [ 5 ]. Preeclampsia is a leading cause of maternal mortality and morbidity accounting for about 12-18% of all pregnancy-related maternal deaths. It is also associated with a high perinatal mortality and morbidity. The only curative treatment for preeclampsia today is to deliver the fetus and removal of the placenta.
Mothers who develop preeclampsia at pregnancy are at increased risk for cardiovascular diseases and diabetes, and their offsprings are at risk for obesity and diabetes, in addition to developmental disorders such as motor and cognitive disorders and blindness.
Reduced uterine perfusion associated with increased vascular resistance can be detected with Doppler ultrasound of the maternal uterine arteries. The increased impedance to the uterine artery perfusion, or increased pulsatility index and Doppler notch indicates that the mother may have a higher risk of developing preeclampsia, resulting in various endothelial problems such as a general endothelial inflammation. The symptoms of preeclampsia typically appear in the third trimester of pregnancy and are usually detected by routine monitoring of the woman's blood pressure and urine proteins
Currently, there are no known cures for preeclampsia except for delivery of the fetus. However, the decision to deliver a patient with preeclampsia must balance both maternal and fetal risks. Preeclampsia can vary in severity from mild to life threatening. A mild form of preeclampsia can remain mild with bed rest and frequent monitoring. For moderate to severe cases, hospitalization is necessary and blood pressure medication and anticonvulsant medications to prevent seizures are prescribed. If the condition becomes life-threatening to the mother or the baby, the only cure is to terminate the pregnancy often resulting in a prematurity of the newborn due to the pre-term delivery. There are two main goals of management of women with preeclampsia: prevention of seizures or eclampsia and control of hypertension. Magnesium sulfate has been used for the prevention of seizures, usually as an intravenous delivery. Daily calcium supplementation and early use of Aspirin may reduce the frequency of the disorder particularly if administered before 16 weeks. Antioxidant vitamins have not been shown to prevent preeclampsia. The management of blood pressure levels with the drugs labetalol or hydralazine has shown benefits although to a limited time.
Novel biomarkers have been found that may be used to detect the syndrome. One such is expressed in the placenta already during the first trimester and may be used to predict pregnancies at risk, a protein called placental protein 13 (PP-13) [ 6 ]. The concentration of PP-13 has been shown to be altered in maternal blood in pregnancy disorders such as preeclampsia. More recent studies have shown that the serum levels of PP-13 are significantly reduced at 6-13 weeks in cases developing early, as well as late-onset preeclampsia [ 7 ]. PP13 is a member of the β-galactoside binding S-type galectin superfamily and is only expressed in placental tissues of higher primates, and within the villous trophoblast it can only be found in the multinucleated syncytiotrophoblast [ 8 ]. PP-13 is expressed and released into the intervillous space, where it enters the maternal circulation and can be detected in maternal blood. While in unaffected pregnancies serum concentrations of PP-13 rise moderately from the first to the third trimester of pregnancy, women who develop preeclampsia start with a lower than normal PP-13 level in the first trimester, and a diagnostic test was develop to use the lower PP-13 level as a measure to predict high risk for preeclampsia. PP-13 levels sharply increase between the first to the third trimester in women who enter the active phase of the disease. This stip change in the level of PP-13 is further assisting in predicting the risk to develop the disorder
SUMMARY OF THE INVENTION
As shown above, there is a need to identify the pregnant subjects at risk of developing pregnancy associated diseases, preferably those at risk of developing preeclampsia and eclampsia, and provide them with the appropriate management regimens. The present invention provides such prevention and/or treatment which has been shown to provide necessary biological effect that will influence the pathophysiology of the disease such as preventing the development of preeclampsia or reducing its severity, when administered into the maternal circulatory system in pregnant women who have been identified to be at risk of suffering from preeclampsia or delivered to the pregnancy in a different way. The best outcome will occur if the pregnant women will receive the treatment, according to the invention, before week 20.
The present invention is based on the inventors' studies on placental protein 13 (PP-13). PP-13 belongs to a group of sugar binding proteins called galectins and they have not been shown to be associated with having cardiovascular, renal or any other biological effect on the stress level. However, this protein or galectin offers more hope of meaningful treatment than any other treatment suggestions available today. Numerous studies on PP-13 have never suggested or associated this protein with recovering the pathophysiology of preeclampsia. Also, the method for diagnosis of pregnant women at risk of developing preeclampsia according to the present invention is very important for this invention. Furthermore, the method for monitoring the progression or regression of the risk factor before week 20 is also important for this invention, in order to help pregnant women to avoid preeclampsia or eclampsia with all the serious risks involved both for the women and/or the fetus.
Surprisingly, PP-13 has been found to cause dilation of arteries and veins, resulting in reduced vascular resistance and preconditioning of the arteries as well as local angiogenesis in uterine arteries and decrease the stress level following administration to a female mammal. Unexpectedly, this is exactly what is needed or what is missing in those women diagnosed with preeclampsia not the active stage of the disease but also in its pre-clinical stage when the underlying pathology is developed. Interestingly, this vasodilation occurs already in the first trimester, forming the connection between low PP-13 and high Doppler impedance as were identified in women at risk to develop preeclampsia. There is a need for a drug or a treatment that may be used as soon as early signs of elevated risk of developing preeclampsia are identified, preferentially as soon as pregnancy is detected, after conception. The optimal start of treatment should occur as soon as low levels of PP-13 has been detected e.g. in week 5-20, preferably in week 6-18 or more preferably in week 7-16.
DETAILED DESCRIPTION
In a first aspect, the invention provides a compound for use as a medicament to affect the pathophysiology of pregnancy to prevent pregnancy associated disease in humans (women) such as but not limited to preeclampsia and/or eclampsia, characterized in that the compound is related to placental protein 13 (PP-13). The compound is preferably human PP-13, most preferably the native full-length protein (as expressed in human tissue) but can also be an active subunit, fragment or derivative thereof.
In another aspect, the invention provides a method of preventing or treating pregnancy associated disease in a female person comprising administering to said person a compound related to PP-13. The pathophysiology affected by the invention can in some embodiments be the physiology of the disease related but not limited to any of the cardiovascular system, renal system, immune system and/or psychology of the disease. Preferably, the compound affects physiology associated with uterine vascularization.
PP-13 to be used according to the invention can be derived from a suitable source, such as human placenta tissue, or over expressed in human or animal cell culture or transgenic organisms or cells expressing human PP-13.
Burger et al. [ 9 ], the teachings of which are hereby incorporated in full, disclose the full sequence of human PP-13 protein and its encoding nucleotide sequence, and teach how the protein can be overexpressed in bacterial cell culture, and isolated and purified. In useful embodiments of the invention other cell cultures are used for the overexpression of PP-13, such as but not limited to cells of human origin, animal cells, fungal cells, or plant cells, or in transgenic organisms such as transgenic animals including mice, pigs, cows, or transgenic plants. In one embodiment the protein is expressed and isolated from BeWo cells, which are regularly used as a cell culture model to mimic in vivo syncytialisation of placental villous trophoblast.
The protein comprises 139 amino acids and has a molecular weight of about 16 kDa (calculated 15.6 kDa). The protein sequence is depicted in the enclosed sequence listing as SEQ ID NO:1 and its encoding cDNA sequence as SEQ ID NO:2 (starting codon at position 15). The PP-13 protein is found in the body as a 32 kDa dimer protein, secreted to the extracellular fluid of the placenta and reaching the maternal blood circulation the amniotic fluid and urine. Both the monomer and dimer as well as oligomers can be used in accordance with the present invention. The protein is expressed in and may be isolated from the placenta and its various layers, from syncytiotrophoblasts, extravillous trophoblasts and chorionic villus from the placenta.
The protein as found in the human body is glycosylated and in preferred embodiments, glycosylated forms are used in the present invention, i.e. glycosylated monomer, dimer or fragment; however non-glycosylated forms are also useful and within the scope of this invention, such as those forms that are expressed in expression systems not capable of protein glycolysation. In some of the accompanying examples, non-glycosylated PP-13 is used, expressed in bacterial expression systems, and these forms exhibit activity in accordance with the invention.
In useful embodiments of the invention, derivatives of PP-13 are used, such as but not limited to PEGylated derivatives that may include PEGylated native protein, or PEGylated subunits or fragments. PEGylation refers to the covalent attachment of polyethylene glycol polymer chains to the protein. Methods for PEGylating proteins are well known to the skilled person, see e.g. Fee [ 10 ].
The compound and methods of the present invention provide for various routes of administration in accordance with the present invention. These include but are not limited to injections (intravenous, intradermal, subcutaneous, or uterine injections), infusions, nasal, pulmonal, rectal, vaginal delivery or administered via cervix or any transdermal or under-dermal device.
Administration of PP-13 will, according to the invention, provide a preconditioning of arteries and angiogenesis as well as an endothelial effect and/or neuronal effect on the uterine vascularization, arteries and/or veins, causing them to dilate and provide and prepare the uterus for the need of receiving increased flow of blood to support, among others, the rapid fetal growth after week 20 in pregnancy.
Administration of PP-13 will, according to the invention, provide a preconditioning of arteries and angiogenesis, an endothelial effect and/or neuronal effect on the systemic vascularization, arteries and/or veins, causing them to dilate, resulting in lower vascular resistance and lower the systemic blood pressure, both systolic as well as diastolic blood pressure, to provide the optimal blood pressure for the placenta, kidneys as well as other organs to function properly during pregnancy. The vasodilation in the kidney and other nonreproductive organs is one of the earliest maternal adaptation's to occur during pregnancy. The administration of PP-13, according to the invention, provides an endothelial effect and/or neuronal effect on the kidney vascularization, arteries and/or veins, causing them to dilate, which is very important to occur before the end of the first trimester. The low level or lack of PP-13, according to the invention, cannot provide the necessary changes in glomerular filtration rate or in the tubular re-absorption before the week 20 after conception unless the maternal body is provided with external administration of PP-13 to prepare the kidneys for the necessary changes.
According to the invention, administration of PP-13 affects the stress level of the mother, by causing central nervous system (CNS) effect and/or affecting the adrenal gland that produces glucocorticoids making the pregnant women more relaxed and prepared for the remaining pregnancy time.
Administration of PP-13 should occur as often as necessary, such as once or more often, and up to unlimited times. Preferably regularly, in a regimen range from a daily dose to a weekly basis, to provide the maternal body with the necessary amount of the protein. The dose should preferably be calculated according, but not limited to following formula:
D =( C desired −C actual )· V d ·W
where D is the dose; C desired is the desired PP13 plasma concentration; C actual is the actual PP-13 plasma concentration; V d is the volume of distribution and W is the body weight. Calculations may need to be adjusted based on serum creatinin, renal clearance, albumin and/or other biological parameters.
In a preferred embodiment, the mammal is a human (women).
In certain embodiments, the compound of the invention is administered in doses that provide a serum concentration of PP-13 in the range of 100-600 pg/mL, preferably in the range of about 150-300 pg/mL and more preferably a concentration in the range of about 175-260 pg/mL. Preferably the compound is administered in a dose that provides equivalent serum concentrations of PP-13 in the range of about 100-600 pg/mL, preferably in the range of about 150-300 pg/mL placental protein 13. Administration of PP-13according to the invention may be carried out alone or in combination with other biologically active compounds such as, but not limited to, relaxin, 17β-estradiol, and/or progesterone.
Such concentrations can be suitably obtained with dose concentrations in injection solutions in the range of about 1-10 μg/mL, such as in the range 2-6 μg/mL, such as about 2, 3, or 5 μg/mL. Suitable injection doses of such injection formulations would be in the range of 200 μL-2 mL, such as in the range 0.5-1 mL.
In embodiments using nasal spray devices, doses in the range of 50-200 μL, such as about 100 μL can be suitable delivered in one or two puffs, as illustrated in the accompanying examples.
In embodiments using vaginal pasery, doses in the range of 5-200 μL, such as about 50 μL can be mixed with a vaginal gel to be suitable for being delivered in one, two or daily use, similar to the way progesterone is used to prevent preterm delivery.
Furthermore, administration of PP-13 may be used in accordance with this invention to preconditioning of arteries in general, especially arteries such as in the heart in both males and female as well as to use PP13 or its derivatives to induce angiogenesis in specific regions of the body such as the brain or the heart in both males and females.
EXAMPLES
PP-13 used in each experiments was a purified human PP-13, expressed in cell culture and/or bacterial culture ( E. coli ), produced (isolated and purified) by Hy-Labs, Ltd. Rehovot, Israel (www.hylabs.co.il).
Example 1
A group of rabbits received 15 ng/kg PP-13 diluted in saline. The administration occurred into the marginal ear vein, slowly over 30 seconds. The animals were observed and sampled for blood samples over the following hours.
Results: The volume of distribution was found to be 221,9 mL/kg and the half-life was found to be 10,6 hours. Within 5 minutes from the beginning of the intravenous drug administration the behavior of the animals changed from being very alert to being relaxed, calm and did not run away when approached for the next blood sample.
Discussion: PP-13 affects the stress levels and makes the animals relaxed and peaceful, which is an important function of PP-13 during pregnancy.
Example 2
Formulations of PP-13 are produced using purified PP-13 (3,0 ug/mL) and PEGylatedPP-13 (equivalent to 3,0 μg/mL of pure PP-13) in saline. About 1 mL of these solutions was administered slowly intravenously to pregnant women in week 11, having the PP-13 levels around 20 pg/mL. Subsequent blood sampling showed that the final serum concentration, 1 hour after the administration is about 200 pg/mL. The women having purified PP-13 require additional doses daily until week 20 from conception, whereas the women receiving PEGylatedPP-13 required additional doses on weekly intervals.
Example 3
A formulation of PP-13 is produced using purified PP-13 (60 μg/mL) and PEGylatedPP-13 (equivalent to 60 μg/mL of pure PP-13) in saline containing 2% methoxypolyethyleneglycole (mPEG 350). The formulation is placed into a multidose nasal spray bottle. Twice daily, the pregnant women who has low serum PP-13 or carry at least one major risk factors to preeclampsia (or two mild ones, stratified according to the WHO) use one puff (about 0,1 mL or 6 μg) of these solutions in week 11, having the PP-13 levels around 20 pg/mL. Subsequent blood sampling showed that the final serum concentration, 1 hour after the administration is about 200 pg/mL. The women having PEGylatedPP-13 needed only one puff per day until week 20 from conception, pregnancy age predefined by last menstrual period or ultrasound dating of pregnancy.
Example 4
Samples are collected from pregnant women. The pregnant woman may be an individual who has been determined to have a high risk of preeclampsia based on her personal or family history or other risk factors as defined by the WHO and/or after determination of the woman's low level PP-13.
A formulation of PP-13 is produced and administered to cervix using pharmaceutically acceptable techniques and formulations in such a way that PP-13 is absorbed through cervix into the uterus.
Example 5
A 244 g rat was anaesthetized with Brietal (50 mg/kg) followed by Inactin (110 mg/kg). After anesthesia the rat was prepared and equipped with blood pressure meter (intra-arterial) on a temperature controlled plate to keep her temperature around 37° C. When the blood pressure was stable (about 45-60 min) the rat received IV dose of 0.1 ml of PP-13 solution (Dose=15 ng). The results obtained are shown in FIG. 1 , illustrating a blood pressure lowering effects of PP-13according to the invention, where the top line shows the blood pressure, the middle line show the pulse and the lowest (dotted) line shows the mean arterial pressure.
Example 6
PP-13 was placed into an Alzet osmotic pump system releasing about 0.14 ng/min. The pumps were placed surgically into gravid female 15 week old Sprague-Dawley rats where the controls received the pumps with saline. Blood PP-13 periodically determined on blood samples and urine collection.
The PP-13 group had significantly lower systolic and diastolic blood pressure than the control animals. At the same time the heart rate increased significantly in the PP-13 group indicating that a general vasodilatation had occurred, reducing the peripheral resistance by about 35%. The placenta also showed angiogenesis.
References
1. ACOG Practical Bulletin. Clinical Management Guidelines for Obstetrician-Gynecologists: Diagnosis and management of preeclampsia and eclampsia, Number 33, January 2002 p. 159-167.
2. Zhou Y, Fisher SJ, Janatpour M, Genbacev O, Dejana E, Wheelock M et al. Human cytotrophoblasts adopt a vascular phenotype as they differentiate: a strategy for successful endovascular invasion? J Clin Invest 1997; 99: 2139-2151.
3. Fox H. The placenta in pregancy hypertension. In: Rubin PC ed handgook of hypertension, volume 10: hypertension in pregnancy. New York: Elsevier 1988: 16-37.
4. Madazli R, Budak E, Calay Z, Aksu MF. Correlation between placental bed biopsy findings, vascular cell adhesion molecule and fibronectin levels in pre-eclampsia. BJOG 2000, 107, 514-518.
5. Walker JJ. Pre-eclampsia. Lancet 2000; 356, 1260-1265.
6. Than NG, Sumegi B, Than GN, Berente Z, Bohn H. Isolation and sequence analysis of a cDNA encoding human placental tissue protein 13 (PP13), a new lysophospholipase, homologue of human eosinophil Charcot-Leyden crystal protein. Placenta 1999; 20, 703-710.
7. Huppertz B, Sammar M, Chefetz I, Neumaier-Wagner P, Bartz C, Meiri H. Longitudinal determination of serum placental protein 13 during development of preeclampsia. Fetal Diagn Ther 2008; 24, 230-236.
8. Than NG, Romero R, Goodman M, Weckle A, Xing J, Dong Z et al. A primate subfamily of galectins expresssed at the maternal-fetal interface that promote immune cell death. Proc Natl Acad Sci USA 2009; 106, 9731-9736.
9. Burger O, Pick E, Zwickel J, Klayman, M, Meiri H, Slotky R, Mandle S, Rabinovitch L, Paltieli Y, Admon A, Gonen, R. Placental Proten 13 (PP-13): Effects on Cultured Trophoblasts, and Its Detection in Human Bodu Fluids in normal and Pathological Pregnancies. Placenta 2004, 25, 608-622.
10. Fee, C. J. (2009), “Protein conjugates purification and characterization”, PEGylated Protein Drugs: Basic Science and Clinical Applications, Veronese, F. M., Ed. Birkhauser Publishing: Basel, 113-125.
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The present invention relates to the biological and pharmacological effects of placental protein 13 (PP-13), an effect that may be used as a treatment and/or prevention of preeclampsia and placental insufficiencies, in pregnant female mammals, especially pregnant women. The invention relates to a method to treat female mammals with the purpose to precondition the uterine arteries and prevent and/or reverse the pathological conditions associated with placental insufficiency such as preeclampsia, HELLP and/or eclampsia.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention is related generally to safety valves. More particularly, this invention pertains to subsurface safety valves which employ a curved flapper for controlling fluid flow through a production tubing string.
[0003] Surface controlled, subsurface safety valves (SCSSVs) are commonly used to shut in oil and gas wells. Such SCSSVs are typically fitted into production tubing in a hydrocarbon producing well, and operate to block the flow of formation fluid upwardly through the production tubing should a failure or hazardous condition occur at the well surface.
[0004] SCSSVs are typically configured as rigidly connected to the production tubing (tubing retrievable), or may be installed and retrieved by wireline, without disturbing the production tubing (wireline retrievable). During normal production, the subsurface safety valve is maintained in an open position by the application of hydraulic fluid pressure transmitted to an actuating mechanism. The hydraulic pressure is commonly supplied to the SCSSV through a control line which resides within the annulus between the production tubing and a well casing. The SCSSV provides automatic shutoff of production flow in response to one or more well safety conditions that can be sensed and/or indicated at the surface. Examples of such conditions include a fire on the platform, a high/low flow line pressure condition, a high/low flow line temperature condition, and operator override. These and other conditions produce a loss of hydraulic pressure in the control line, thereby causing the flapper to close so as to block the flow of production fluids up the tubing.
[0005] 2. Description of the Related Art
[0006] Most surface controlled subsurface safety valves are “normally closed” valves. This means that the valves utilize a flapper type closure mechanism which is biased in its closed position. In many commercially available valve systems, the bias is overcome by longitudinal movement of a hydraulic actuator. In some cases the actuator of the SCSSV comprises a concentric annular piston Most commonly, the actuator comprises a small diameter rod piston located in a housing wall of the SCSSV.
[0007] During well production, the flapper is maintained in the open position by a flow tube connected downhole to the actuator. From a reservoir, a pump at the surface delivers regulated hydraulic fluid under pressure to the actuator through a control conduit, or control line. Hydraulic fluid is pumped into a variable volume pressure chamber (or cylinder) and acts against a seal area on the piston. The piston, in turn, acts against the flow tube to selectively open the flapper member in the valve. Any loss of hydraulic pressure in the control line causes the piston and actuated flow tube to retract, which causes the SCSSV to return to its normally closed position by a return means. The return means serves as the biasing member, and typically defines a powerful spring and/or gas charge. The flapper is then rotated about a hinge pin to the valve closed position by the return means, i.e., a torsion spring, and in response to upwardly flowing formation fluid.
[0008] In some wells, high fluid flow rates of as much as 250 million cubic feet or more per day of gas may be produced through the SCSSV. In high flow rate wells, it is well known that curved or arcuate flappers may be used to provide a larger inside diameter, or bore, in the SCSSV as compared to a flat flapper. Examples of such SCSSVs are described in U.S. Pat. Nos. 2,162,578; 4,531,587; 4,854,387; 4,926,945; 5,125,437; and 5,323,859. Curved flapper arrangements enable a larger production tubing inner diameter and, thus, allow for a greater rate of hydrocarbon production through the valve area.
[0009] In either flat or curved flappers, as the tubular piston and operator tube retract, the flapper closure passes across the lower end of the operator tube and throttles the flow as it rotates toward the closed or “seated” position. At high flow rates, a high differential pressure may be developed across the flapper that may cause distortion and warping of the flapper as it rubs against the operator tube. Also, a flapper seat may be damaged if it is slammed open against the valve housing or slammed shut against the valve seat in response to the high-pressure differentials and production flow regimes. Damage to the flapper seat or leakage around the flapper may also occur if the flapper is closed on any debris in the well, such as sand or other aggregate that may be produced with the hydrocarbons.
[0010] In prior art SCSSVs, the flapper is seated in a variety of configurations. The flapper may be seated against an annular sealing face, either in metal-to-metal contact, or metal against an annular resilient seal.
[0011] In U.S. Pat. No. 3,955,623 discloses a flapper having a flat, annular sealing face. The flapper is engagable against a flat, annular valve seat ring, with sealing engagement being enhanced by an elastomeric seal ring that is mounted on the valve seat.
[0012] U.S. Pat. No. 4,457,376, the valve seat includes a downwardly facing, conical segment having a sloping sealing surface. The flapper closure member has a complimentary, sloping annular sealing surface that is adapted for surface-to-surface engagement against the conical valve seat surface.
[0013] U.S. Pat. No. 5,125,457, (expired) also presents a curved flapper. The flapper has a sealing surface with a convex spherical radius which seats in a matching concave housing. It also has a concave spherical portion constructed of an elastomeric material. The spherical radius flapper/seat has an alternate embodiment shown in U.S. Pat. No. 5,323,859. This patent teaches metal-to-metal sealing surfaces with no resilient seal.
[0014] In U.S. Pat. Nos. 5,682,921, and 5,918,858 a flat sealing surface is provided on both the flapper and the seat, fashioned in a sinusoidal undulating shape and having a combination metal and resilient seal.
[0015] In all these arrangements, the flapper rotates about a hinge assembly that comprises a hinge pin and a torsion spring. It will be appreciated by those of ordinary skill in the art, that structural distortion of the flapper, or damage to the hinge assembly which supports the flapper for rotational movement into engagement with the valve seat, can cause misalignment of the respective sealing surfaces, thereby producing a leakage path around the flapper.
[0016] Misalignment of the flapper relative to the valve seat may also be caused by the deposition of sand particles or other debris on the valve seat and/or sealing surfaces. Sand may be produced in both gas and oil wells, under low flow rate conditions as well as high flow rate conditions. It is particularly difficult to obtain positive sealing engagement of either flat or curved flappers and valve seats in low-pressure, sandy environments.
[0017] The integrity of the sealing engagement between the flapper and valve seat may be compromised under low flow rate conditions, while the same safety valve may provide positive closure and sealing engagement under high flow rate, high differential pressure conditions In this respect, slight misalignment may be overcome by high-pressure impact and engagement of the flapper against the valve seat. However, the same misalignment may produce a leakage path under low differential pressure conditions. Such misalignment will prevent correct seating and sealing of the flapper. The result is that a large amount of formation fluid may escape through the damaged valve, wasting valuable hydrocarbon resources, causing environmental pollution, and creating potentially hazardous conditions for well operations personnel. During situations involving damage to the wellhead, the well flow must be shut off completely before repairs can be made and production resumed. Even a small leak through the flapper safety valve in a gas well can cause catastrophic damage.
[0018] The following U.S. Pat. Nos. pertain to SCSSVs having flapper closure mechanisms and are hereby incorporated by reference: 3,788,595; 3,865,141; 3,955,623; 4,077,473; 4,160,484; 4,161,960; 4,287,954; 4,376,464; 4,449,587; 4,457,376; 4,531,587; 4,583,596; 4,605,070; 4,674,575; 4,854,387; 4,890,674; 4,926,945; 4,983,803; 4,986,358; 5,125,457; 5,137,090; 5,263,847; 5,323,859; 5,423,383; 5,285,851; 5,918,858; 5,682,921.
SUMMARY OF THE INVENTION
[0019] The present invention provides an improved flapper and seat for a surface controlled subsurface safety valve (SCSSV). The SCSSV of the present invention provides a curved flapper having a novel sealing surface for engaging a novel corresponding sealing surface in the seat. The sealing surface of the flapper is configured to contact the sealing surface of the seat along a sinusoidal sealing line, or seam, such that the reactive force from the seat is normal to the sinusoidal seating line. Thus, a more effective seal is achieved when the flapper pivots to its closed position. In operation, the novel SCSSV will safely and effectively shut in a well below the earth's surface in the event of damage to the wellhead or flow line, or in the event of a malfunction of any surface equipment, with the shut-in being accomplished whether the well is operating in low flow or in high flow conditions.
[0020] The present invention also provides an improved surface-controlled, subsurface flapper safety valve in which the flapper closure mechanism and valve seat are tolerant of irregularities, such as obstructions or surface distortions caused by sand deposits or erosion of their respective sealing surfaces. The present invention also provides an improved flapper mechanism and seat in an SCSSV assembly having, in one embodiment, a flapper having a spherical sealing surface, and a corresponding metallic seat having a conical sealing surface. In one aspect, the sealing surface of the flapper has a convex spherical configuration relative to the seat. The sealing surface of the seat, in turn, has a concave conical shape relative to the flapper. In such an arrangement, the present invention provides an improved valve seat for an SCSSV adapted to provide a positive seal against a curved or arcuate flapper closure mechanism to overcome imperfect alignment or surface finish of its sealing surface relative to the safety valve seat.
[0021] The present invention also provides an improved flapper mechanism and seat in an SCSSV assembly having, in another embodiment, a flapper having a spherical sealing surface, and a corresponding metallic “hard” seat having a conical sealing surface. Disposed concentrically within the hard seat is also a “soft” valve seat made of a yieldable material such as an elastomer (nitrile, neoprene, AFLAS®, KALREZ®), a thermoplastic polymer (TEFLON®, RYTON®, or PEEK®), or a soft metal (lead, copper, zinc and brass). The soft seat defines a concave spherical or conical segment. The surfaces of the hard seat and the soft seat are configured to lie in sealable contact within the spherical radius that defines the sealing surface on the flapper. The surfaces are configured to provide a positive seal along a continuous interface seam between the conical hard seat, the (optional) resilient soft seat and the concave spherical sealing surface of the flapper.
[0022] According to the foregoing alternative arrangement, a convex spherical sealing segment of the flapper is received in nesting engagement against the surface of the soft seat, and against the conical sealing segment of the hard seat. The nesting arrangement allows for some misalignment of the flapper relative to the valve seat without interrupting surface-to-surface engagement therebetween. In this respect, the surface of the soft seat will tolerate a limited amount of angular misalignment of the flapper that might be caused by structural distortion of the closure or deflection of the hinge assembly, enabling a low-pressure seal. Line contact between the convex spherical segment of the flapper and the conical hard seat serves to realign the flapper as pressure increases. The hard seat also supplies sufficient structural rigidity to enable a pressure seal at high pressures. Positive sealing engagement between the flapper and the hard and soft seats is also obtained in sandy environments by engagement of the yieldable seat which conforms about surface irregularities which may be caused by surface deposits or surface erosion caused by the production of sandy fines.
[0023] It will be appreciated by one of ordinary skill in the art, that the foregoing net result of this interaction, is a flapper and seat system that performs in a sandy environment throughout any pressure range required in a hydrocarbon producing well for both tubing retrievable and wireline retrievable SCSSVs, and for both hydraulic or electrically actuated embodiments thereof.
[0024] As has been described in detail above, the present invention has been contemplated to overcome the deficiencies of the prior equalizing safety valves specifically by disclosing significant improvements to the flapper closure mechanism and the corresponding seat. The novel features of the invention are set forth with particularity in Detailed Description of Preferred Embodiments and The Claims. The invention will best be understood from the following description when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] So that the manner in which the above recited features of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
[0026] [0026]FIG. 1 is a semi-diagrammatic schematic, in cross section, of a typical production well having a surface controlled, tubing retrievable subsurface safety valve installed according to the present invention;
[0027] [0027]FIG. 2 is an isometric view, in partial section, of a tubing retrievable subsurface safety valve of the present invention shown in the open position;
[0028] [0028]FIG. 3 is an isometric view, in partial section, of a tubing retrievable subsurface safety valve of the present invention shown in the closed position;
[0029] [0029]FIG. 4 is a close-up detailed isometric view, in partial section, of a flapper and seat in the all-metal configuration (without a soft seat) in a subsurface safety valve of the present invention, shown in the closed position;
[0030] [0030]FIG. 5 is an exploded isometric view of a flapper/seat subassembly of the present invention, shown in the closed position and without a soft seat;
[0031] [0031]FIG. 6 illustrates a sphere and cone sealing method and seal interface line in accordance with prior art.
[0032] [0032]FIG. 7 is an exploded isometric view of a flapper/seat subassembly of the present invention, shown in the closed position and with a combination soft/hard seat;
[0033] [0033]FIG. 8 is a cross-sectional view of a flapper/seat subassembly of the present invention, shown in the closed position and with soft seat/hard seat configuration;
[0034] [0034]FIG. 9 is a cross-sectional view of a flapper/seat subassembly of the present invention, shown in the open position and with the soft seat/hard seat configuration;
[0035] [0035]FIG. 10 is an isometric view of a flapper and seat in the soft seat/hard seat configuration of the present invention shown in the open position, incorporated into a substrate safety valve;
[0036] [0036]FIG. 11 is a close-up detailed isometric view, in partial section, of a flapper and seat in the soft seat/hard seat configuration of the present invention shown in the closed position, incorporated into a subsurface safety valve;
[0037] [0037]FIG. 12 is an isometric view of a flapper and seat in the soft resilient seat/hard seat configuration in a subsurface safety valve of the present invention shown in the closed position with a flapper closing means;
[0038] [0038]FIG. 13 is an exploded isometric view of a metal-to-metal flapper and seat in a subsurface safety valve of the present invention shown in the open position with a flapper closing means and an equalizing means;
[0039] [0039]FIG. 14 is an exploded isometric view of a metal-to-metal flapper and seat in a subsurface safety valve of the present invention shown in the closed position with a flapper closing means and an equalizing means; and
[0040] [0040]FIG. 15 is an enlarged isometric view of a closed flapper/seat subassembly in partial section, which illustrates details of the all-metal flapper and seat of the present invention.
[0041] [0041]FIGS. 16, 17, 18 and 19 are rotated isometric views of the flapper closure mechanism.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0042] In the description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawings may be but are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the invention. One of normal skill in the art of subsurface safety valves will appreciate that the present invention can and may be used in all types of subsurface safety valves, including but not limited to tubing retrievable, wireline retrievable, injection valves, subsurface controlled valves (such as storm chokes), or any type of flapper safety valve that benefits from a larger flow area by the employment of a curved or arcuate flapper closure mechanism.
[0043] Referring now to FIG. 1, a subsurface safety valve 10 is shown in place in a typical well completion schematic 12 . A land well is shown for the purpose of illustration; however, it is understood that a subsurface safety valve 10 of the present invention may be commonly used in offshore wells. Visible in the well 12 of FIG. 1 are a wellhead 20 , a master valve 22 , a flow line 24 , a casing string 26 , production tubing 28 , and a packer 30 . In operation, opening the master valve 22 allows pressurized hydrocarbons residing in the producing formation 32 to flow through a set of perforations 34 and into the well 12 . The packer 30 seals an annulus 35 between the casing 26 and the production tubing 28 in order to direct the flow of hydrocarbons. Hydrocarbons (illustrated by arrows) flow into the production tubing 28 , through the subsurface safety valve 10 , through the wellhead 20 , and out into the flow line 24 .
[0044] Referring now to FIG. 2, a subsurface safety valve 10 of the present invention is shown in the open position. An upper nipple 36 and a lower sub 38 serve to sealingly connect the safety valve 10 to the production tubing 28 . The safety valve 10 is maintained in the open position by hydraulic pressure. Hydraulic pressure is supplied by a pump (not shown) in a control panel 14 through a control line 16 to the safety valve 10 . The hydraulic pressure holds a flapper closure mechanism 18 within the safety valve 10 in the open position. Because the safety valve 10 is a “fail closed” device, loss of hydraulic pressure in the control line 16 will cause the flapper closure mechanism 18 to actuate, thereby blocking the upward flow of hydrocarbons to the surface.
[0045] As noted, the safety valve 10 shown in FIGS. 1 and 2 is hydraulically actuated. In this respect, the safety valve 10 includes a hydraulic chamber housing 40 and a piston 42 therein. The piston 42 is typically a small diameter piston which moves within a bore of the housing 40 in response to hydraulic pressure from the surface. Alternatively, the piston may be a large concentric piston which is pressure actuated. It is within the scope of the present invention, however, to employ other less common actuators such as electric solenoid actuators, motorized gear drives and gas charged valves (not shown). Any of these known or contemplated means of actuating the subsurface safety valve 10 of the present invention may be used.
[0046] Energizing the actuating means 42 serves to open the subsurface safety valve 10 . In the arrangement of the safety valve 10 shown in FIG. 2, the application of hydraulic pressure through the control line 16 serves to force the piston 42 within the chamber housing 40 downward. The piston 42 , in turns, acts upon a flow tube 44 , translating the flow tube 44 longitudinally. In FIG. 2, the flow tube 44 is shown shifted fully downward due to the energy from the actuating means 42 . In this position, the flow tube maintains the flapper closure mechanism 18 (obscured by flow tube 44 in this figure) in an open position.
[0047] [0047]FIG. 3 presents the safety valve of the present invention in its closed position. In this position, the flapper 18 is blocking the wellbore. A power spring 46 is shown in its fully compressed position acting on a connecting means 48 , allowing the power spring 46 to bias the flow tube to an upward position.
[0048] When pressure (or energy) is released from the piston 42 as shown in FIG. 3, the power spring 46 moves the flow tube 44 longitudinally upward, allowing the flapper closure mechanism 18 to close, and thereby preventing flow from the well.
[0049] [0049]FIG. 4 depicts, in quarter section, a close up view of a portion of the closed subsurface safety valve 10 of FIG. 3. Features illustrated are the flow tube 44 , a lower end of the power spring 46 , and the flapper closure mechanism 18 , all arranged inside the lower sub 38 .
[0050] Referring now to FIG. 5, FIG. 5 presents an exploded isometric view of a flapper/seat subassembly of the present invention. The flapper 18 is shown in the closed position with a metal-to-metal seal. A hard seat 50 adapted for use in a safety valve 10 has a concave conical sealing surface 58 formed therearound. A flapper mount 60 is affixed to the hard seat 50 by a plurality of attachment screws 62 threaded into a plurality of threaded holes 63 . Close tolerance alignment pins 64 assure a precision alignment between a centerline of the flapper mount 60 and the hard seat 50 . A clevis pair 66 is fashioned into the flapper mount 60 wherein a mounting hole 68 is drilled through for receiving at least one flapper pin 70 . The curved flapper 18 is rotatably mounted on the at least one flapper pin 70 by a hinge 72 , having pin hole 74 drilled therethrough. Thus, the flapper 18 pivots between its open and closed positions about the flapper pin 70 .
[0051] In operation, the curved flapper 18 swings in an arc of substantially 80-90 degrees between its opened and closed positions about the pin 70 . In its open position, the flapper 18 is positioned essentially vertically so as not to obstruct the upward flow of hydrocarbons from the well. In its closed position, the flapper 18 seals essentially horizontally within the well so as to obstruct the upward flow of fluids. The flapper 18 is configured to meet a sealing surface 58 in the seat 50 . In the arrangement shown in FIG. 5, the flapper 18 includes a convex spherical sealing surface which engages a corresponding convex spherical sealing surface in the seat 50 .
[0052] The convex spherical sealing surface 76 formed on the curved flapper 18 results in a slightly elliptical flapper shape. FIGS. 16 - 19 more clearly depict the elliptical shape.
[0053] The geometrical configurations of the sealing surfaces 58 , 76 in the present invention are complex. Visualization of the complexity of this geometry in a two dimensional environment for most requires illustration of a simpler and well-known sealing device. Reference is thus made to the sealing device often employed in “poppet type” valves. FIG. 6 shows a simplified prior art arrangement of a convex spherical poppet seal 52 and a convex conical seat 54 , the sealing surface of the seat being tangent to the spherical radius of the poppet seal 52 . The interface between the spherical poppet 42 and the convex conical seat 54 forms a flat circular sealing line 56 . Pressure forces acting on the spherical poppet 42 creates very high local stresses along the sealing line 56 , thereby affecting a fluidic seal along the flat circular sealing line 56 . The seating line 56 represents every point on the convex conical seat 54 that is tangent to the surface of the spherical poppet seal 52 . Visualizing this tangency is helpful in understanding the geometry of the present invention. The flapper and seat seal of the present invention is related to the ball and cone poppet seal, but is more complex. The flat circular sealing line 56 of the poppet seal will not transcribe onto the geometry of a curved flapper with a spherical sealing segment. In this respect, the curved flapper is designed to maximize the inside diameter of a SCSSV.
[0054] In recent years, engineers and designers have employed highly advanced computerized software known generically as parametric solid modeling. Parametric solid modeling software is marketed under various brand names including: PRO-ENGINEER™, SOLID WORKS™, and SDRC-IDEAS™. Use of such software allows the designer to create and visualize geometries that are difficult or even impossible to describe in two-dimensional media, including two-dimensional drawings. Manufacturers first realized the difficulty where traditional drawings could not be used to either build or inspect parts. Means were created to translate the computerized electronic geometry directly to machine code. This increases capability, and efficiency and saves time over manufacturing processes that require drawings. It also provides the only means for reliably manufacturing a flapper and seat arrangement of the present invention.
[0055] The present invention, and specifically the interaction of the convex spherical sealing surface 76 and the concave conical sealing surface on the hard seat 50 , can more easily be visualized in the “soft seat” embodiment hereinafter described in FIG. 7.
[0056] In FIG. 7, the hard seat 50 again has a concave conical sealing surface 58 . However, it also has a seat recess 78 for receiving a soft seat 80 . As before, flapper mount 60 is affixed to the hard seat 50 by a plurality of attachment screws 62 threaded into a plurality of threaded holes 63 . Close tolerance alignment pins 64 assure a precision alignment between a centerline of the flapper mount 60 and the hard seat 50 . A clevis pair 66 is fashioned into the flapper mount 60 wherein a mounting hole 68 is drilled through for receiving at least one flapper pin 70 . The curved flapper closure mechanism 18 is rotatably mounted on the at least one flapper pin 70 by a hinge 72 , having pin hole 74 drilled therethrough.
[0057] In operation, the curved flapper closure mechanism 18 pivots in an arc of substantially 80-90 degrees between its opened and closed positions about the pin 70 . The concave conical sealing surface 58 of the seat 50 is adapted to receive the closed flapper closure mechanism 18 of the present invention upon which a convex spherical sealing surface 76 is formed.
[0058] The interaction between the concave conical sealing surface 58 of the seat 50 and the convex spherical sealing surface 76 of the flapper 18 is along a pair of sinusoidal sealing lines. First, a hard sinusoidal sealing line 82 is formed in the hard seat 50 ; second, a soft sinusoidal sealing line 84 is formed on the soft seat 80 . Not obvious in this figure is the “angle” of the concave conical sealing surface. A single conical angle is represented by line 86 . In order to provide the desired seal with the flapper 18 , this conical angle 86 must be substantially tangent to a flapper sealing line 88 on the convex spherical sealing surface of the flapper 18 . It must also be substantially tangent to a sinusoidal sealing line 82 formed in the hard seat 50 and the soft sinusoidal sealing line 84 formed on the soft seat 80 . (The flapper sealing line 88 is illustrated in FIGS. 16 - 19 .) This means that the conical angle 86 depicted must be variable circumferentially around a cross-sectional perimeter of the hard seat 50 .
[0059] As earlier discussed, the variable conical angle 86 cannot be accurately depicted in this 2-D format. Computer software was used to generate the required solid model geometry to depict the part, as well as the machining code necessary to manufacture the part. A Coordinate Measuring Machine or CMM may be used to inspect manufactured parts for accuracy. For purposes of this disclosure, it must be understood that the angle of intersection between the sealing surfaces 58 , 76 varies along the perimeter of the flapper 18 .
[0060] When it becomes necessary to close, the flapper 18 rotates about the pin 70 until it begins to nest in the hard seat. The flapper sealing line 88 on the convex spherical sealing surface 76 first contacts the sinusoidal sealing line 84 formed on the soft seat 80 . This interaction allows for an effective seal at low pressures. The soft seal 80 is fabricated from a resilient material. Preferably, the resilient seat is constructed of an elastomeric material having a durometer hardness in the range of 60 to 99. Other materials, however, are satisfactory for the soft seat 80 . Acceptable examples include a thermoplastic polymeric material, e.g., tetrafluoroethylene (TFE) fluorocarbon polymer or polyetheretherkeytone (PEEK), a reinforced thermoplastic containing carbon or glass, or a soft metallic material, e.g., lead, copper, zinc, gold or brass.
[0061] At higher pressures, the resilient nature of the soft seat material deforms. The flapper sealing line 88 on the flapper seating surface 76 engages the sinusoidal sealing line 82 formed in the hard seat 50 . This interaction allows for a high-pressure seal. Forces along the sinusoidal sealing line due to pressure are resolved very efficiently in the present invention. The reactive force from the hard seat normal to the sinusoidal sealing line inhibits and virtually eliminates the metaphorically descriptive “Taco Effect”, or tendency of prior art curved flappers to bend like the familiar food item when subjected to high pressure. Any such bending in a flapper can cause undesirable leakage and possible failure. The present invention also resolves stresses in the flapper and seat in a very efficient manner.
[0062] Reference is now made to FIGS. 8 and 9. FIGS. 8 and 9 present cross-sectional views of a flapper 18 of the present invention, along with a resilient soft seat 80 , the hard seat 50 , the flapper mount 60 , and the hinge 72 . In FIG. 8, the flapper 18 is in its closed position. In FIG. 9, the flapper 18 is shown in the open position. FIG. 9 also clearly shows an interface between the hard sinusoidal seating line 82 and the soft sinusoidal seating line 84 .
[0063] [0063]FIG. 10 provides an assembled isometric view of a flapper closure mechanism 18 , a hard seat 50 , and a soft seat 80 for use in a subsurface safety valve 10 of the present invention, shown in the open position. Also visible in this view is an interface between the hard sinusoidal seating line 82 and the soft sinusoidal seating line 84 , as well as the convex spherical sealing surface 76 on the flapper 18 .
[0064] [0064]FIG. 11 is a close-up detailed isometric view, in partial section, of a flapper closure mechanism 18 , a hard seat 50 , and a soft seat 80 for use in a subsurface safety valve of the present invention. In this view, the valve 10 is shown in the closed position. The soft seat 80 is configured to protrude above the hard seat 50 . As the flapper 18 closes, the resilient soft seat 50 initially engages the flapper 18 to provide a low-pressure seal. As pressure increases, the flapper closure mechanism 18 moves to contact the hard seat 50 , thereby providing the valve with a high-pressure seal.
[0065] [0065]FIG. 12 is an assembled isometric view of a safety valve of the present invention, shown in the closed position. A flapper spring means 92 for biasing the flapper 18 to the closed position is seen. One of ordinary skill in the art of safety valve design will understand that there are many well-known means to bias a flapper 18 to the closed position. . Use of any type of spring means to close the flapper 18 of the present invention is regarded within the scope and spirit of the present invention.
[0066] [0066]FIG. 13 is an assembled isometric view of the safety valve of FIG. 12, shown in the open position. A flapper spring means 92 for biasing the flapper closure mechanism 18 to the closed position is again shown. Also depicted, is an optional equalizing valve means 94 . In FIG. 13, the pressure equalizing means 94 is a dart.
[0067] The equalizing means 94 shown in FIG. 13 is a well-known device for equalizing differential pressures across the flapper 18 When the flapper 18 is closed, pressure builds up below, and acts on the flapper's surface area. This pressure force may be as high as 20,000 psig. This amount of force is too great for the flow tube 44 to overcome. Therefore, a means of equalizing pressure is required in order for the flapper 18 to open. When it becomes necessary to open the SCSSV, the flow tube 44 (not shown in this view) translates downward and contacts the dart 94 . Dart 94 includes an opening which permits fluid to bleed through the valve 10 , thereby equalizing pressure above and below the flapper 18 . When pressure substantially equalizes across the flapper 18 , the flow tube 44 translates axially downward and fully opens the SCSSV.
[0068] [0068]FIG. 14 is an exploded isometric view of a safety valve 10 of the present invention, shown in the closed position. The valve 10 also includes a pressure equalizing means 94 . The valve 10 of FIG. 14 utilizes metal-to-metal contact between the flapper 18 and the seat 50 . Visible are the flapper mount 60 , the flapper pin 70 , a leaf spring 96 , an equalizing dart 94 , and at least one dart spring 100 . A hole 102 is machined through the flapper for receiving the dart 98 . The at least one dart spring 100 biases the dart 94 to a closed position.
[0069] [0069]FIG. 15 is an enlarged isometric view of a flapper 18 , a hard seat 50 , and a flapper mount 60 . . This Figure illustrates details of the all-metal flapper and seat engagement of the present invention, in one aspect.
[0070] [0070]FIGS. 16, 17, 18 , and 19 are rotated isometric views of the curved flapper 18 used in a valve 10 of the present invention. These Figures show the substantially elliptical shape of flapper 18 . Also shown in these rotated views are the convex spherical sealing surface 76 of the flapper 18 , and the sinusoidal shape of the flapper sealing line 88 .
[0071] It should be noted that while a tubing retrievable embodiment is shown and discussed herein, the curved flapper and seat of the present invention might also be adapted for use in a wireline retrievable subsurface safety valve. Operation of the tubing retrievable subsurface safety valve 10 is otherwise in accord with the operation of any surface controllable, wireline retrievable safety valves that employ this invention.
[0072] Although the invention has been described in part by making detailed reference to specific embodiments, such detail is intended to be and will be understood to be instructional rather than restrictive. As has been described in detail above, the present invention has been contemplated to overcome the deficiencies of the prior equalizing safety valves specifically by improving the sealing capabilities of curved flapper subsurface safety valves.
[0073] Whereas the present invention has been described in relation to the drawings attached hereto, it should be understood that other and further modifications, apart from those shown or suggested herein, might be made within the scope and spirit of the present invention.
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A curved flapper and seat is disclosed for use in a subsurface safety valve. The flapper is biased to a normally closed position to prevent fluid flow through the wellbore. The curved flapper has a sealing surface for engaging a corresponding sealing surface on a seat when the flapper is in its closed position. The sealing surface of the flapper is configured to contact the sealing surface of the seat along a sinusoidal sealing line, or seam, such that the reactive force from the seat is normal to the sinusoidal seating line. In one aspect, the sealing surface of the flapper has a convex spherical configuration relative to the seat. The sealing surface of the seat, in turn, has a concave conical shape relative to the flapper. When well conditions dictate, a resilient soft seat may optionally be used, and is disposed on the seat proximate the sinusoidal seating line.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of the U.S. National Stage designation of co-pending International Patent Application PCT/EP2003/050782 filed Nov. 3, 2003, which claims priority to U.S. provisional application No. 60/424,681 filed Nov. 8, 2002 and European patent application no. 02405995.8 filed Nov. 19, 2002, and the entire contents of these applications are expressly incorporated herein by reference thereto.
FIELD OF THE INVENTION
The invention relates to a method of operating a gas turbine power plant and a gas turbine power plant.
BACKGROUND OF THE INVENTION
In the last years different projects were launched with the aim to develop emission free gas turbine based processes using semi-closed cycles with CO 2 /H 2 O mixtures as working fluid. Methods of operating such power plants are known for example from EP-A1-0 939 199 and EP-A1-0 953 748. In these processes the fuel, usually natural gas, reacts with technically pure oxygen generated either in an external air-separation unit or internally in an integrated membrane reactor. One major disadvantage of using air-separation units for these kind of processes is that they consume a great amount of energy, thus penalizing the efficiency and power output of the plant. From the literature it can be found that the energy demand for air-separation units is as high as 0.3 kWh/kg O 2 produced. The energy consumption for separating the oxygen from the air can be decreased very much if oxygen-separating membranes are used. Also this technique has a few disadvantages, namely: metal to ceramic sealing is needed that can withstand temperatures >800° C., the turbine inlet temperature (TIT) and the ceramic sealing temperature are linked, which limits the maximum TIT and thus lowers the performance of the plant and one needs to separate large amounts of air, corresponding to the total O 2 required for full oxidation of fossil fuel powering the gas turbine.
SUMMARY OF THE INVENTION
The present invention relates to providing a method of operating a gas turbine power plant and a gas turbine power plant which avoid disadvantages of the prior as well as increasing the overall efficiency of the power plant.
This present invention is related to making use of so-called partial oxidation (POX) of the natural gas to syngas consisting of CO and H 2 . The oxygen required for this partial oxidation is provided by a ceramic, air separation membrane, thermally integrated into the process. This syngas would then be water gas shifted to produce even more hydrogen and convert the CO to CO 2 , and finally use the produced hydrogen as fuel in a gas turbine.
By doing this, one would overcome the temperature limit previously set by the membrane. The membrane reactor unit would be combined to both work as an oxygen transferring membrane and as a reactor for the partial oxidation. One membrane type that can be used to separate the oxygen from the air is a so-called “Mixed Conducting Membrane” (MCM). These materials consist of complex crystalline structures, which incorporate oxygen ion vacancies (5-15%). The transport principle for oxygen transport through the membrane is adsorption on the surface followed by decomposition into ions, which are transported through the membrane by sequentially occupying oxygen ion vacancies. The ion transport is counterbalanced by a flow of electrons in the opposite direction completing the circuit. The driving force is a difference in oxygen partial pressure between the permeate and retentate sides of the membrane. The transport process also requires high temperatures, i.e. >700° C. In an embodiment of the present invention the surfaces of the permeate side of the membrane that contain the syngas are coated with catalytic material to promote the formation of synthesis gas 17 1 and, in particular, hydrogen. Catalyst materials used for autothermal reforming are Rh, Ru, Co, Fe or bimetallic combinations thereof.
Optionally, prior to entering the membrane reactor, the air stream from the compressor can be lead to a catalytic burner where the air is heated by means of catalytic combustion. The fuel for the catalyst is either hydrogen or natural gas. Thereby the use of hydrogen is preferred to avoid producing CO 2 . The reason for using a catalytic burner is to increase the average temperature in the membrane/POX reactor thereby increasing the oxygen flux through the membrane. Also, the temperature gradient in the reactor will be lower and thus the thermal stresses for the reactor will decrease.
Advantageously the syngas coming from the membrane/POX reactor consisting of hot steam, H 2 and CO can enter a low temperature heat exchanger, where the syngas mixture is cooled down by an incoming stream of the compressed air from the compressor. Another possibility would be to use a medium temperature heat exchanger to raise the temperature of the mixture of steam and natural gas before the mixture enters the membrane/POX reactor. This would flatten out the temperature profile in the membrane/POX reactor and thus lower the temperature gradients in this.
After the expansion the hot flue gases of the gas turbine can be utilised in a heat recovery steam generator producing steam for the bottoming steam cycle and producing more power in a steam turbine and electricity in a generator.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are illustrated in the accompanying drawings, in which:
FIG. 1 illustrates a gas turbine power plant according to the present invention; and
FIG. 2 illustrates the partial oxidation of the membrane/partial oxidation reactor.
The drawings show only the parts important for the invention. Same elements will be numbered in the same way in different drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a syngas based low emission power plant according to the present invention. Air 1 is fed through a compressor 2 before the compressed air 3 is fed at least through a membrane/partial oxidation (POX) reactor 4 . After the membrane/POX reactor 4 the air is burned in a combustion chamber 5 together with hydrogen 6 . The flue gases are then expanded in a turbine 7 , which is driving the compressor 2 and producing electricity in a generator 8 . After the expansion the hot flue gases 9 are utilised in a heat recovery steam generator 10 producing steam for the bottoming steam cycle 11 and producing more power in a steam turbine 12 and electricity in a generator 13 .
As can be seen from FIG. 1 , natural gas 14 is being mixed with superheated intermediate pressure steam 15 and is then lead to the membrane/POX reactor 4 . One possibility here would be to use a medium temperature beat exchanger 16 to raise the temperature of the mixture of steam 15 and natural gas 14 . This would flatten out the temperature profile in the membrane/POX reactor 4 and thus lower the temperature gradients in this. Since the temperature involved is not too high (<900° C.), it might be possible to use a metal heat exchanger.
As seen in FIG. 2 , in the membrane/POX reactor 4 , oxygen is transferred through a membrane 18 from a first side to a second side and is partially oxidised (as well as reformed with steam) on the membrane 18 surface with the natural gas 14 by the following reactions:
CH 4 +0.5O 2 2H 2 +CO+35.67 kJ/mol
CH 4 +H 2 O CO+3H 2 −205 kJ/mol
CO+H 2 O CO 2 +H 2 +41.15 kJ/mol
In sum, the three reactions combine to produce a mixture of H 2 , CO and CO 2 ; the overall heat balance and product mixture is dictated by the amount of oxygen (and endothermic reactions) that is present. The design of the membrane/POX reactor 4 is such that the overall process is autothermal, and the membrane temperature is of ca. 800° C. The membrane/POX reactor 4 would be combined to both work as an oxygen transferring membrane and as well as doing the partial oxidation. One membrane type that can be used to separate the oxygen from the air is a so-called “Mixed Conducting Membrane” (MCM). These materials consist of complex crystalline structures, which incorporate oxygen ion vacancies (5-15%). The transport principle for oxygen transport through the membrane 18 is adsorption on the surface followed by decomposition into ions, which are transported through the membrane by sequentially occupying oxygen ion vacancies. The ion transport is counterbalanced by a flow of electrons in the opposite direction. The driving force is a difference in oxygen partial pressure between the permeate and retentate sides of the membrane 18 . The transport process also requires high temperatures, i.e. >700° C. In an embodiment of the present invention the surfaces of the permeate side of the membrane 18 (that containing the syngas 17 1 ) is coated with catalytic material to promote the formation of synthesis gas 17 1 and, in particular, hydrogen. Catalyst materials used for autothermal reforming are Rh, Ru, Co, Fe or bimetallic combinations thereof (e.g. Co/Fe).
The syngas 17 1 , now consisting of hot steam, H 2 and CO enters a low temperature heat exchanger 19 , where the syngas 17 1 mixture is cooled down by an incoming stream of the compressed air 3 from the compressor 2 . Optionally, the air stream from the low temperature heat exchanger 19 can then be lead to a catalytic burner 20 where the air is heated by means of catalytic combustion. The fuel for the catalytic burner 20 is either hydrogen 21 or natural gas 14 . Use of hydrogen 21 is preferred to avoid producing CO 2 . The reason for using a catalytic burner 20 is to increase the average temperature in the membrane/POX reactor 4 , increasing the oxygen flux through the membrane 18 . Also, the temperature gradient in the reactor 4 will be lower and thus the thermal stresses for the reactor 4 will decrease. This catalytic burner 20 can also be used to help control process conditions within the MCM reactor during start up or to address instabilities within the membrane/POX reactor 4 associated with the autothermal reforming and potential catalyst deactivation. The temperature of the MCM reactor will be very sensitive to the amount of O 2 present and there could be some strange transients during start up. A quick reacting catalytic burner 4 running on H 2 could help for process control.
After the syngas 17 1 has been cooled down in the low temperature heat exchanger 19 , the syngas 17 1 is then further cooled down in a CO shift reactor 22 , lowering the temperature further to about 200-300° C. Depending on the chosen cooling temperature, water will condense out or not. Since a low temperature favors the CO shift reaction it might be wise to keep the temperature low. This will also lower the water consumption for the cycle since the condensed water 23 can be re-injected in the bottoming steam cycle 11 . The medium used for the cooling is boiler feed water 24 1 , 24 2 from a bottoming steam and water cycle 11 . During the cooling of the syngas 17 1 , in the CO shift reactor 22 , the syngas 17 1 undergoes the following reaction:
CO+H 2 O H 2 +CO 2 +41.15 kJ/mol
The CO shift reactor 22 is in other words used to convert CO and water to CO 2 and more hydrogen. Also this reaction is mildly exothermic, leading to some of the water which was condensed out during the cooling (or all water if the cooling temperature is high) being evaporated again, taking heat from the exothermic process described above. After the CO shift reactor 22 the syngas 17 2 consists ideally of H 2 , CO 2 and H 2 O. This syngas 17 2 is then lead to some kind of CO 2 absorption equipment 25 , based on either chemical or physical absorption. The CO 2 removal rate in this kind of equipment is around 90%. Low pressure steam 26 needed for the CO 2 removal is extracted from the steam turbine 12 , and the condensed water 27 is lead back to the feed water tank of the steam cycle 11 . The removed CO 2 28 is further compressed by means of inter-cooling in a compressor 29 , producing liquid CO 2 30 that might be deposited or used in for instance enhanced oil recovery.
After removing most of the CO 2 , the syngas 17 3 mainly consisting of H 2 , H 2 O and some remaining CO 2 is lead to a combustion chamber 5 , to be burned together with air from the first side of the membrane/POX reactor 4 . The water in the syngas 17 3 helps control the combustion temperature and thus lowers NO x formation. A part of the resulting syngas 17 3 comprising hydrogen 6 from the CO 2 removal equipment 25 can as well be burned in the catalytic burner 20 .
LIST OF DESIGNATIONS
1 Air
2 Compressor
3 Compressed air
4 Membrane/partial oxidation (POX) reactor
5 Combustion chamber
6 Hydrogen
7 Gas turbine
8 Generator
9 Hot flue gases
10 Heat recovery steam generator
11 Bottoming steam cycle
12 Steam Turbine
13 Generator
14 Natural gas
15 Superheated steam
16 Medium temperature heat exchanger
17 1 , 17 2 , 17 3 Syngas
18 Membrane
19 Low temperature heat exchanger.
20 Catalytic burner
21 Hydrogen
22 CO shift reactor
23 Condensed water
24 Boiler feed water
25 CO 2 absorption equipment
26 Low pressure steam
27 Condensed water
28 CO 2
29 compressor
30 liquid CO 2
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A method of operating a gas turbine power plant and gas turbine power plant are disclosed wherein hydrogen for the combusting process is produced by feeding natural gas mixed with steam through a membrane/partial oxidation reactor and converting the natural gas at least to H 2 and CO. Thereby oxygen is transferred from the compressed air through the membrane of the membrane/partial oxidation reactor and the oxygen is used for the partial oxidation process of the natural gas. The process is followed by converting the syngas in a CO shift reactor and a CO shift reactor to a CO 2 removal equipment to mainly hydrogen.
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FIELD OF THE INVENTION
The present invention concerns the field of dentistry, and especially relates to improved dental restorations.
BACKGROUND OF THE INVENTION
Composite restorative materials are finding ever-increasing use in dentistry. Although current composites are designed primarily for use as restorations for anterior and other non-load-bearing regions of tooth structure, these materials (perhaps prematurely) are being applied to the posterior acclusal region as well. As anterior restorative materials, many of the current composites have performed reasonably well, although clinical and other studies have shown that these esthetic filling materials have several significant shortcomings; namely, color instability, lack of stain resistance, marginal leakage and chemical erosion which contributes to anatomic loss.
The susceptibility of the organic matrix to chemical disintegration is a likely critical factor contributing to the wear of dental composites both in stress-bearing and stress-free applications. The complex interaction of composite restorations with the many chemical substances (e.g. H 2 O, O 2 , food-related chemicals, etc.) found in the oral environment, can by diffusion-controlled processes initially lead to plasticization, and ultimately to chemical degradation of the polymer matrix. Since they exists in a predominantly aqueous environment, the transport of other chemical substances into the polymer phase is likely to be water-assisted.
The solubility parameter of the dental resin system employed for restorative materials, its water-related properties (e.g., water sorption), and its degree of polymerization and crosslinking, are important factors governing the extent of chemical softening and disintegration that will occur in dental composites. The relatively hydrophilic matrices of conventional bis-GMA (2,2,-bis[4'(3"-methacroyl-2"-hydroxypropoxy)phenyl]propane) or urethane methacrylate copolymer systems have solubility parameters similar to certain chemical substances (e.g. food derived chemicals) found in the oral cavity. Composites based on these resin systems, therefore, will display an affinity not only for water but also for many of the chemical moieties generated intraorally. The complex sorption/desorption processes that occur in these composites may induce not only stresses but also degenerative chemical reactions that accelerate the failure of these restorative materials.
U.S. Pat. No. 4,292,029 to Craig et al employs a large amount of fluorinated alkyl methacrylate (1,1,5-trihydrooctafluoropentyl methacrylate, OFPMA) in conjunction with an analog of bis-GMA in an attempt to overcome the drawbacks of the conventional bis-GMA resin system. The hydrophobic composite represents a significant advance in designing an esthetic restorative material with enhanced resistance to the assaults of the oral environment. The dental resin system suffers however from several serious deficiencies, namely (a) loss of OFPMA on mixing because of its relatively high vapor pressure and its greater potential for irritation than a bulky fluorinated monomer of low vapor pressure; (b) undesirably greater opacity than desirable because of the relatively low refractive index of OFPMA and (c) low strength.
The relatively low crosslinked density of the OFPMA polymeric matrix results in composites of relatively low strength which fail to meet the minimum requirement for diametral tensile strength (34 MPA) established by the American Dental Association. In addition, such composite materials exhibit a relatively high contraction on polymerization. Craig mentions but does not give actual examples of composites derived from fluorinated bis-GMA analogs or other fluorinated dimethacrylates (e.g. tetrafluoroethylene glycol dimethacrylate); the existence of the latter is doubtful. Also, the use of fluorinated silane agents is mentioned, but again, no examples of how they are used are given. The fluorinated silane agents (e.g. hydrooctafluorobutyltrichlorosilane) cited are actually not coupling agents and their sole or improper use leads to extremely weak composites. Only the dual silanization procedure disclosed below leads to strong composites having excellent compatibility of the resin and filler components.
SUMMARY OF THE INVENTION
Accordingly, the invention relates to improved hydrophobic dental resin systems, especially such systems containing a high concentration of fluorinated monomers. More generally, it is an object of the invention to overcome deficiencies in the prior art, such as indicated above; and to provide for improved dental materials and their use.
Composites based on such dental resin systems have polymeric matrices that are highly immune to chemical softening and chemical degradation. The composites are not readily wet by water or saliva; exhibit extremely low water sorption and marginal leakage; and are also relatively oleophobic, which further enhances their resistance to surface staining; and have lesser opacity because of higher refraction index (compared to OFPMA). Further, and importantly, the composites demonstrate low polymerization shrinkage, which tends to generate stress points at composite-cavity wall interfaces.
In particular, the invention relates to the use of bulky, highly fluorinated methacrylate monomers in preparing dental resin systems having reduced water sorption and polymeric shrinkage characteristics but at least adequate strength. The use of 1,1 dihydropentadecafluorooctyl methacrylate (PDFOMA), a bulky highly fluorinated monomethacrylate (PFMMA), with PFMA, a bulky highly fluorinated multifunctional methacrylate according to formula II below and known as PFMA: ##STR1## is uniquely different from the prior art dental resins.
The PFMA prepolymers employed herein are highly fluorinated, multiacrylated monomers which comprise fluorinated analogs of the widely used bis-GMA or of similar difunctional or multifunctional, non-fluorinated prepolymer monomers (e.g. urethane derivatives of bis-GMA derived from bis-GMA and diisocyanates such as 1,6-hexamethylene diisocyanate). Both types of multifunctional monomers yield polymeric matrices that are highly cross-linked. However, the present fluorinated, crosslinking or thermosetting monomers, in addition impart a low surface energy character to the matrices similar to that of fluorocarbon polymers such as poly(tetrafluoroethylene). Such low surface energy polymeric matrices are highly resistant to the absorption of aqueous fluids (i.e. they are hydrophobic) and to staining by food derived products (e.g. they tend to be oleophobic).
The crosslinking nature of these highly fluorinated resins is important because it reduces the solubility of the resin components and leads to composite and sealant materials of enhanced strength, excellent dimensional stability, excellent chemical resistance, and extremely low permeability to fluid penetration. These features are especially critical if dental composite and sealant materials are to have a long service life in the oral environment. By contrast, currently used resin-based dental materials have a relatively high permeability to oral fluids which leads to chemical softening or plasticization and ultimately to degradation of the composite or sealant.
PFMA is preferably a prepolymer product. The prepolymer product is both highly fluorinated and multifunctional, and possesses an extremely high molecular weight, but yet has a relatively modest viscosity for its great bulk. This oligomeric or prepolymer compound is compatible with a wide range of both hydrocarbon and fluorocarbon diluent monomers, and thus, it is possible to vary the content of covalently bound fluorine in the dental resin over a wide range. Because of its bulky nature and the minimal amounts of diluent monomer needed to obtain dental resins of workable viscosities, PFMA based resins yield dental composite and sealant materials having very low shrinkage on polymerization. This latter property is of importance because of this very modest polymerization contraction leads to composites and sealants with less residual stresses and, also, improves margin adaptability of the material to the cavity walls, thereby reducing the potential for microleakage and the formation of secondary caries.
The systems comprising PFMMA employed herein are single-phase resin systems based on non-hydroxylated derivatives of bis-GMA and including a minor portion of fluorinated monofunctional alkyl methacrylate, especially PDFOMA, as diluent. These systems exhibit characteristics comparable to the systems comprising PFMA described supra. Both systems are useful in a variety of dental applications including composites, cements, and sealants. The refractive indices of dental resins based on PFMA and similar PFMA prepolymers are in the range of N D 25 ° C. =1.420 to 1.460 which is compatible with many particulate glass fillers. Thus, composites based on PFMA and silanized fillers of the above type are translucent enough to be used as anterior restorations where esthetics are an important consideration. Composites prepared according to the dual silanization process according to the present invention, wherein filler is sequentially reacted with a silane coupling agent and fluorinated silane, are particularly preferred.
DETAILED DESCRIPTION OF THE INVENTION
The invention comprises dental resin systems including highly fluorinated alkyl methacrylate monomers or prepolymers, and dental materials, especially composites, prepared therefrom.
In one embodiment of the invention, the system includes a major portion of non-hydroxylated homolog or analog of bis-GMA, and a highly polyfluorinated alkyl monomethacrylate (PFMMA) as diluent monomer. Highly perfluorinated alkyl monomethacrylates of the formula I: ##STR2## wherein R is CH 2 --(CF 2 ) x F or CH 2 --(CF 2 ) x --H, and x is at least 5, usually from 2 to about 10, are preferred, especially the former, and most especially PDFOMA.
In another embodiment of the invention, the resin system is based on a highly polyfluorinated multifunctional methacrylate prepolymer (PFMA) preferably in combination with one or more diluent monomers to reduce viscosity; a number of diluent monomers unexpectedly function to increase strength of the system. The preferred multifunctional methacrylate prepolymer is PFMA according to the following formula II, in combination with one or more relatively hydrophobic fluorocarbon- or hydrocarbon-alkyl methacrylate monomer diluents of the type exemplified in Table I or II, below: ##STR3##
PFMA is a known compound described, e.g. in J. Dent. Res. 58: Spec. Issue A (1979).
Products according to the invention prepared from these dental systems include dental composites comprising polymeric matrices and silanized glass filler; preferably, silanized glass fluorosilanized according to the process of the invention is employed as filler for good composite strength.
The systems and composites of the present invention represent an improvement over prior art systems, retaining important water-related characteristics of the prior art materials, and also providing significantly improved physical and mechanical properties, especially good strength and dimensional stability.
PFMMA systems according to the invention are prepared by combining a minor proportion [less than about 15% (w/w), preferably from 5 to 12% (w/w)], of fluorinated monomethacrylate of the formula I (PFMMA) with a nonhydroxylated homolog or analog of bis-GMA; a preferred monomethacrylate of the formula I is 1,1-dihydropentadecafluorooctyl methacrylate (PDFOMA); preferred bis-GMA variants include 2,2-bis (p-beta-methacryloxy ethoxy) phenyl propane(bis-EMA) or an oligomeric urethane methacrylate containing a diluent monomer and known as a non-hydroxylated derivative of bis-GMA: ##STR4##
(Generalized chemical structure of the oligomeric urethane methacrylate component of the NCO monomer [bis-GMA(NCO)] which also contains a diluent monomer. R is an aliphatic hydrocarbon connecting group for the urethane functional groups.)
Attempts to prepare single phase formulations using high concentrations of PDFOMA and bis-EMA or the urethane derivative of bis-GMA were unsuccessful. With 1,10-decamethylene dimethacrylate (DMDMA) as a third monomer it was possible to obtain single phase formulations containing 8-11% by weight of PDFOMA. Composites prepared with PDFOMA resins had excellent diametral tensile (DTS) and compressive strengths (CS) (48 MPA and 253 MPA, respectively) but were not expecially hydrophobic.
PFMA systems according to the invention are prepared by blending a polyfluorinated multifunctional methacrylate (i.e. PFMA, one having a plurality of reactive vinyl groups) with a compatible diluent monomer to reduce prepolymer viscosity without adversely affecting valuable properties. Especially suitable monomers are relatively hydrophobic alkyl methacrylates, alkylene dimethacrylates or fluoroalkyl methacrylates of the types exemplified in Tables I and II. Alkyl groups containing from about 2-12 carbon atoms are especially contemplated with DMDMA, NPDMA and PDFOMA being particularly useful. Mixtures of diluent monomers are also used to advantage.
These systems have major amounts of hydrocarbon and/or fluorocarbon-diluent monomers (e.g. DMDMA, PDFOMA). Composites dereived from these PFMA resins have good mechanical properties (DTS=39 MPA and CS=188 MPA) and are extremely hydrophobic. The latter reflects the mechanically strong composites obtained from low surface energy polymeric binders.
Composites are suitably prepared by incorporating reinforcing filler into the polymerized or prepolymerized resin systems as known in the prior art. In the preferred embodiment of the invention, fluorosilanized glass is employed as filler. In order to preserve the strength of the composite, glass filler particles are silanized in known manner with a silane coupling agent, followed by silanization with a fluorinated silane agent such as 1,1,2,2,-tetrahydrotridecafluorooctyldimethyl chlorosilane; the resultant fluorosilanized glass is employed as filler in amounts of from about 25 to 85 wt. % of resin system, as exemplified in Table V. Suitable glass starting materials include commercial glass filler such as borosilicate glass powder, quartz, fused quartz and fused silica.
The following examples are included as illustrative of the invention.
EXAMPLES
Materials and Methods
The hydrocarbon and fluorocarbon monomers employed, with their names, abbreviations, chemical structures, molecular weights and sources are given in Tables I and II below. The amine polymerization accelerators employed are similarly listed in Table III below. In addition, some formulations contained the multifunctional chain transfer agent, pentaerythritol tetra(3-mercaptoproprionate), PETMP, and additional inhibitor in the form of BHA (2,6-di-tert-butyl-4-methylphenol). The synthesis of the polyfluoro-prepolymer multifunctional methacrylate, PFMA, was previously described (Antonucci, J. M.; New Monomers for Use in Dentistry, Organic Coatings and Plastic Chemistry (ACS) 42, 198-203, 1980; Antonucci, J. M.; New Monomers for Use in Dentistry, Biochemical and Dental Applications of Polymers, Eds. Gebelein, C. G. and Koblitz, F. F.; Plenum Press, N.Y., N.Y., 357-371, 1981). The chemical structure and some properties of PFMA are given above. A generalized representation of the chemical structure of the oligomeric urethane methacrylate in the NCO monomer, bis-GMA(NCO), is given above. This oligomeric monomer contains a diluent comonomer (e.g. triethylene glycol dimethacrylate).
EXAMPLE I
Resins Based on PDFOMA
Preliminary experiments to prepare a resin analogous to that derived from OFPMA (3)/bis-EMA (J. Dent. Res. 58: 1981-86, 1979) but using the more highly fluorinated PDFOMA in place of OFPMA were unsuccessful. The two monomers were incompatible at high concentrations (e.g. 20-70) of PDFOMA with phase separation occuring at ambient temperature. Similar results were obtained using bis-GMA (NCO) in place of bis-EMA and equally high concentrations of PDFOMA.
With DMDMA as a mutually miscible co-diluent it was possible to prepare bis-EMA/DMDMA resin formulations having 8-11 wt. % of PDFOMA. With bis-GMA (NCO) and DMDMA, similar amounts (8-10 wt. %) of PDFOMA were easily incorporated into resin formulations.
EXAMPLE II
Preparation of Reinforcing Filler
(a) A-174 Silanized Glass with 1 wt. % Benzoyl Peroxide
A commercial glass (Corning Glass, 7725, Corning Glass Works, Corning, N.Y.) powder containing barium oxide was silanized by a modification of a procedure described previously (J. Dent. Res. 61:1439-43, 1982 incorporated herein by reference). The glass powder was weighed into a round bottom flask and sufficient cyclohexane was added to give a loose slurry on swirling (e.g. 100 g of powder per 100 ml of cyclohexane). Based on the weight of the powder, a solution of 0.5 wt. % 3-methacryloxypropyltrimethoxysilane (A-174) (Corning Corp., N.Y., N.Y.) and 2.0 wt. % n-propylamine was added to the slurry and the flask was connected to a rotary evaporator. The slurry was mixed for one hour at atmospheric pressure at room temperature. After this period the flask was heated at 60°-65° C. by means of a water bath and moderate vacuum (20-30 mm Hg) was applied to the rotating flask. After the cyclohexane was removed, the flask was cooled to room temperature and the vacuum disconnected. The powdered silanized glass was swirled with fresh cyclohexane and the solvent decanted through a filter under a moderate vacuum. This procedure was repeated several times with fresh solvent in order to remove traces of the amine and soluble silane products. The glass powder was finally dried by exposure to a high vacuum (approximately 1 mm Hg) for 25 hours. The silanized glass was then coated with 1 wt. % benzoyl peroxide using a dilute solution of this peroxide in methylene chloride and the usual rotary evaporation procedure.
(b) Fluorosilanized glass (F-Glass) with 1 wt. % benzoyl peroxide
A portion of the previously silanized (A-174) glass was given a second silanization treatment with 0.5 wt. % of tridecafluoro-1,1,2,2-tetrahydrooctyldimethylchlorosilane (TDFOS) (Petrarch Systems, Inc., Bristol, PA) in cyclohexane containing 1 wt. % triethylamine by the same procedure used to prepare the A-174 silanized glass. The F-glass was then coated with 1 wt. % benzoyl peroxide by the deposition procedure previously described.
EXAMPLE III
Resins Based on PFMA
(a) Formulation of Composites
Known powder/liquid formulation techniques were used to prepare glass filled composites according to the resin formulations shown in Tables IV and V. Filler was prepared according to Example II. Filler was blended with oligomer PFMA and diluent monomer and the admixture polymerized in known manner (Antonucci publications, supra, incorporated herein by reference).
(b) Evaluations of Composites
(i) Setting Time.
The setting times of the various composite formulations were measured as described in ADA Specification No. 8 except that the specimen is transferred to the 100% relative humidity chamber at 37° C. one minute after mixing the powder and liquid components. Testing with the Gilmore needle commences after 1.5 min. from the start of the mix and continues every 0.5 min. until a setting time is determined.
(ii) Diametral Tensile Strength
The diametral tenside strengths of the composites were determined according to ADA Specification No. 27 (JADA 94:1191-94, 1977).
(iii) Compressive Strength
The compressive strengths of the composites were determined by a procedure similar to that employed for the determination of the diametral tensile strengths (JADA 94, op.cit.). Specimens were prepared in molds, 6 mm×12 mm, and crushed using a crosshead speed of 0.5 cm/min.
(iv) Water Sorption
The determination of water uptake of the composite specimens was performed in accordance with ADA Specification No. 27 (JADA 94, op.cit.). In addition, a new technique involving near infrared spectroscopy was used for measuring the water sorption of several thin composite specimens (50-100 μm) prepared by polymerization between crossed microscope slides (Anal. Chem. 33: 1947-47, 1961). Absorbance due to water occurs in a very transparent region of the near infrared spectrum at 5203-5220 cm -1 (2.0-1.9 μm).
(c) Results
1. PDFOMA Based Composites
The setting times, diametral tensile strengths (DTS), compressive strengths (CS) and water sorption values of composites prepared from resin systems consisting of bis-EMA/DMDMA or bis-GMA (NCO)/DMDMA with relatively modest quantities (8-11 wt. %) of PDFOMA as a secondary diluent monomer are given in Table IV. The wt. % of covalently bound fluorine in this type of fluoro-resin system is only 4.9-6.8.
All composites had acceptable setting times and DTS values in excess of the minimum (34 MPa) required by the ADA Specification; CS values were in the range 178-253 MPa, typical of many conventional composites. Water sorption covered a range 0.28-0.72 mg/cm 2 , also typical of many conventional composites. However, most of the values tended toward the low end of the water sorption scale.
One unexpected consequence of using PDFOMA in these formulations was a significant increase in the setting times of the usually very reactive resins based on bis-EMA or bis-GMA(NCO) and DMDMA. For example, a resin system consisting of equal parts by weight of bis-GMA(NCO) and DMDMA with 0.4 wt. % BDMA and 0.1 BHT wt. % set in less than a minute when mixed with 3 parts of silanized glass coated with 1 wt. % benzoyl peroxide. Similar formulations with 8-10 wt. % PDFOMA had markedly longer setting times (5-7, Table IV). By contrast, the replacement of PDFOMA by n-octyl methacrylate (OMA), the hydrocarbon analog of PDFOMA in the bis-GMA(NCO)/DMDMA monomer system resultd in composites with shorter setting times (9 and 10, Table IV). 9 contains an amount of OMA (4.05 wt. %) equivalant in molality to the PDFOMA in 7, Table IV. 10 (Table IV) which had the lowest water sorption (0.28 mg/cm 2 ) of all the bis-GMA(NCO)/DMDMA composites contains more than twice this molal concentration of OMA. It was not possible to prepare a single phase formulation of this resin system with an equivalent amount (approx. 20 wt. %) of PDFOMA.
It is believed that resin formulations containing significant quantities of highly fluorinated monomers such as PDFOMA may dissolve more oxygen than hydrocarbon resin systems and, therefore, may be more sensitive to air inhibition. This inhibitory effect can be compensated by the use of higher concentrations of the amine polymerization accelerator (e.g. 5, Table IV). The esthetics and color stability of the composite were compromised by this approach. A more satisfactory solution is to use modest amounts of the high molecular weight, multifunctional chain transfer agent, PETMP, which functions both as a synergistic accelerator, reactive diluent and agent for ameliorating the effects of air inhibition. The esthetics, color stabilities and mechanical properties of composites prepared with PETMP were superior to those prepared without the polythiol.
The use of the dual silanized F-glass as a filler was not effective in reducing water uptake but, in some cases, an improvement in mechanical strength was noted (compare 3, 4, 5, 6, 8A Table IV). With fluoro-resin systems, especially those of high fluorine content (e.g. PFMA), it was found that F-glass facilitated the mixing of powder/liquid formulations.
2. PFMA Based Composites
The setting times, DTS and some CS and water sorption values for composites prepared from resin systems utilizing PFMA as the major monomeric component are given in Table 5. The wt. % of covalently bound fluorine ranged fron 30.4 to 41.5 for this type of fluoro-resin system.
As can be seen from Table V, a great variety of diluent monomers can be used with PFMA ranging from MMA to bis-EMA. In addition fluorocarbon methacrylates such as OFPMA and PDFOMA also are compatible with PFMA. All the composites had suitable working characteristics and setting times. The 24 hour DTS values are in the 30-40 MPa range, but with most formulations giving composites exceeding the ADA minimum of 34 MPa. Formulation 6A which a somewhat deficient 24 hour DTS of 32.3 MPa increased in strength to about 36 MPa after 48 hours (Table V). Similar increases in strength with time were noted for formulation 31 (24 h DTS=39; 1 W DTS=42 MPa) and for formulation 4 (24 h DTS=38, 2W DTS=39 MPa). Formulation 31 also had remarkably low water sorption (Table V). Formulations 3H, 7A and 7B (Table V) had CS values of 165, 159 and 188, respectively, which are similar to those of some conventional composites. The water sorption values are in the exceedingly low range of 0.13-0.23 mg/cm 2 , similar to that of the hydrophobic composites based on OFPMA/bis-EMA. Preferred difunctional methacrylate hydrocarbon diluent monomers are NPDMA, DMDMA, HMDMA, bis-MA and bis-EMA. Some of these monomers require the use of a second diluent monomer to be effective. The trifunctional methacrylate, TMPTMA, which gave high strength composites with bis-GMA, failed to strengthen similar PFMA composites.
The use of binary or ternary diluent systems for PFMA often resulted in an increase in strength properties of the fluoro-composite. For example, formulation 1 which employed only MMA as a diluent yields a composite with a DTS of 31 MPa whereas formulation 2, which also utilized NPDMA and PETMP gave significantly higher strength (DTS=40 MPa) materials (Table V). The use of a second crosslinking diluent such as NPDMA and TMPTMA should have a similar strengthening effect on PFMA/TMPTMA based composites.
The use of PETMP aided the esthetics, color stability and, often, the strength properties of these composites. With modest amounts of PETMP less of the amine polymerization accelerator is required to obtain the same setting time and at least equivalent DTS values (compare 3A and 3B with 3C and 3D, Table V). With PETMP and the same content of amine accelerator, shorter setting times and higher DTS values are obtained (Compare 3F and 3G with 3H and 3I, Table V).
As part of a binary or ternary diluent monomer systems, the bulky solid dimethacrylates, bis-MA and bis-EMA, were miscible with PFMA (4, 10A, 10B, 10C, Table V). In formulation 10A, the very fluid hydrophobic resin, OFPMA (3)/bis-EMA (1) of Craig et al (e.g. U.S. Pat. No. 4,292,029; J. Dent Res. 58: 1981-86, 1979) was used as the diluent for PFMA and gave composites of good strength (DTS=38 MPa). A variant of this formulation (10B, 10C) using a ternary diluent system of OFPMA, bis-EMA and NPDMA also gave hydrophobic composites of good strength (DTS=38 and 40 MPa, respectively.) 9A and 9B (Table V) which used HFIPMA as the major diluent monomer and NPDMA as the minor diluent monomer for PFMA also gave hydrophobic composites with good strength properties. 7A and 7B, (Table 5) which used DMDMA as the only diluent monomer, gave composites with good strength properties and extremely low water uptake. As noted above, the use of F-glass did not enhance the hydrophobicity of the composite system but did improve the ease of mixing of these powder/liquid formulations.
(d) Water Sorption by Near-Infrared Spectroscopy
In contrast to determination of water sorption by the method outlined in ADA Specification No. 27 which requires immersion of relatively large specimens in water, correction for solubility effects, long equilibration times and the measurement of small changes in large numbers, the near-IR method has the following advantages: (1) thin films which have short equilibration times are used, (2) comparative measurements after immersion in water versus simple exposure to atmospheres of 100% relative humidity (which eliminates leaching or solubility effects) can be made and (3) the time dependent water-sorption behavior of the specimen may be easily monitored. The spectra obtained indicate the sensitivity of this method.
The extreme reluctance to water uptake by the composite film derived from PFMA (3H, Table V) is made strikingly evident by the absence of any absorbance peak for water after the dry composite film is exposed to the same humid atmosphere for 24 hours.
As expected, water-related properties, such as water sorption, for these PFMA based composites are similar to the hydrophobic composites reported by Craig et al. The significantly greater mechanical strength of the PFMA derived composites compared to those derived from OFPMA/bis-EMA probably is a conseqience of the greater degree of crosslinking possible with the PFMA based resins which yields polymeric matrices of higher glass transition temperatures than those obtainable with the OFPMA/bis-EMA monomer system.
Due to the prepolymer nature of principal monomeric component, PFMA, and its relatively low viscosity, PFMA based composites and sealants exhibit rather low polymerization contraction.
TABLE I__________________________________________________________________________Hydrocarbon Monomers MolecularName Abbreviation Chemical Structure Weight Source__________________________________________________________________________Methyl Methacrylate MMA ##STR5## 100 Aldrich Chemical Co. Milwaukee, WINeopentyl Dimethacrylate NPDMA ##STR6## 240 Esschem Essington, PA1,10-Decamethylene Dimethacrylate DMDMA ##STR7## 310 Esschem Essington, PA1,6-Hexamethylene Dimethacrylate HMDMA ##STR8## 254 Esschem Essington, PAn-Octyl Metahcrylate OMA ##STR9## 198 Polysciences, Inc. Warrington, PA2,2-BIS[p-(Metha- cryloxy) Phenyl] Propane BIS-MA ##STR10## 364 Polysciences, Inc. Warrington, PA2,2-Bis[p-(Metha- cryloxyethyloxy) Phenyl] Propane BIS-EMA ##STR11## 444 ESPE GAMBL Seefeld, GermanyTrimethylol Propane Trimethacrylate TMPTMA ##STR12## 338 ESSCHEM Essington, PANCO Monomer BIS-GMA (NCO) See Text >1000 L. D. Caulk Co. Milford,__________________________________________________________________________ DE
TABLE II__________________________________________________________________________Fluorocarbon Monomers MolecularName Abbreviation Chemical Structure Weight Source__________________________________________________________________________HexafluoroIsopropyl Methacrylate HFIPMA ##STR13## 236 Columbia Organic Chemicals, Columbia, SCOctafluoropentyl Methacrylate OFPMA ##STR14## 300 PCR Research Chemicals, Inc., Gainesville, FLPentadecafluorooctyl Methacrylate PDFOMA ##STR15## 468 Columbia Organic Chemicals, Columbia, SCPolyfluorinated PFMA See formula II 10,320 SynthesizedPolymethacrylate__________________________________________________________________________
TABLE III__________________________________________________________________________Polymerization Accelerators MolecularName Abbreviation Chemical Structure Weight Source__________________________________________________________________________p-Tert-Butyl-N,N Dimethylaniline BDMA ##STR16## 177 Aldrich Chemical Co. Milwaukee, WIPN,NDimethyl- aminophenethanol DMAPE ##STR17## 165 Aldrich CHemical Co. Milwaukee, WIN,NDimethyl-sym- xylidine DMSX ##STR18## 149 Aldrich Chemical Co. Milwaukee WIPN,NDiethyl- aminophenylacetic Acid DEAPAA ##STR19## 207 Synthesized__________________________________________________________________________
TABLE IV__________________________________________________________________________COMPOSITION AND PROPERTIES OF EXPERIMENTAL COMPOSITESFORMULATED WITH BIS-EMA OR BIS-GMA/NCO AND DMDMA AND PDFDMA Strength, MPa WaterForm Liquid Composition Setting Diametral Sorption % FNo. WT % Time (Min) Tensile.sup.a Compressive.sup.a (mg/cm.sup.2) in Resin__________________________________________________________________________1 BIS-EMA 44.31 5.0 36.0 (2.8).sup.b 174 (4) -- 6.8 DMDMA 44.31 PDFOMA 11.15 BDMA 0.232 BIS-EMA 44.25 3.5 41.0 (3.0) 208 (27) 0.72 (0.16) 6.8 DMDMA 44.25 PDFOMA 11.15 BDMA 0.353 BIS-EMA 49.25 3.0 43.2 (1.2) -- 0.28 (0.02) 5.6 DMDMA 41.25 48.5 (3.5).sup.c .sup. 0.32 (0.01).sup.c PDFOMA 9.30 BDMA 0.204 BIS-EMA 45.91 3.0 43.4 (2.9) -- -- 4.9 DMDMA 45.91 41.0 (3.1).sup.c PDFOMA 7.98 BDMA 0.205 BIS-GMA/NCO 51.58 4.5 40.5 (2.9).sup.b 232 (8).sup.b 0.41 (0.14) 4.9 DMDMA 39.84 46.3 (2.2).sup.c 248 (10).sup.c .sup. 0.36 (0.14).sup.c PDFOMA 8.07 BDMA 0.41 BHT 0.106 BIS-GMA/NCO 54.77 4.0 42.8 (4.6) -- -- 4.6 DMDMA 33.48 45.7 (2.3).sup.c PDFOMA 9.18 PETMP 2.22 BDMA 0.25 BHT 0.107 BIS-GMA/NCO 58.55 4.5 40.3 (3.3) 210 (16) 0.71 (0.05) 5.5 DMDMA 31.68 PDFOMA 9.02 BDMA 0.57 BHT 0.188 BIS-GMA/NCO 57.70 4.5 46.1 (3.3) 253 (4) 0.43 (0.03) 5.4 DMDMA 31.06 45.5 (5.2).sup.c 251 (16).sup.c .sup. 0.57 (0.03).sup.c PDFOMA 8.87 PETMP 1.99 BDMA 0.20 BHT 0.189 BIS-GMA/NCO 62.20 2.5 41.7 (4.1) 221 (4) 0.36 (0.05) 0 DMDMA 33.45 OMA* 4.05 BDMA 0.20 BHT 0.1010 BIS-GMA/NCO 50.90 2.0 34.8 (4.5) 165 0.28 (0.09) 0 DMDMA 39.47 OMA 8.97 EDMA 0.36 BHT 0.30__________________________________________________________________________ *OMA = nOctyl Methacrylate, Hydrocarbon Analog of PDFOMA .sup.a Average of 5 determinations .sup.b Standard Deviation .sup.c Using FGlass
TABLE V__________________________________________________________________________Composition and Properties of Experimental CompositesBased on PFMALiquid Setting Strength (MPa) WaterForm Composition P/L Time Diametral Tensile Compressive Sorption Wt. PercentNo. (wt. %) Ratio.sup.c (min) (std. dev.).sup.a (std. dev.).sup.a (mg/cm.sup.2) F in Resin__________________________________________________________________________1 PFMA 86.55 3 5.0 30.9 (1.1).sup.b -- -- 38.3 MMA 12.91 DMAPE 0.542 PFMA 72.80 3.5 2.5 39.7 (2.8) -- -- 32.2 NPDMA 14.00 MMA 10.80 PETMP 2.00 DMAPE 0.403A PFMA 70.50 3.5 3.0 34.0 (3.3) -- -- 31.2 NPDMA 29.10 DMAPE 0.403B PFMA 70.45 3.5 3.0 36.5 (1.2) -- -- 31.1 NPDMA 29.09 DMAPE .453C PFMA 69.59 3.5 3.5 35.6 (3.0) -- -- 30.8 NPDMA 28.70 PETMP 1.55 DMAPE 0.163D PFMA 69.51 3.5 3.0 38.7 (0.9) -- -- 30.7 NPDMA 28.62 PETMP 1.55 DMAPE 0.283E Same as 3D 3.5 3.0 38.8 (1.2) -- -- 30.7 with F-Glass3F PFMA 70.00 3.5 5.0 35.5 (0.2) -- -- 30.9 NPDMA 29.55 DEAPAA 0.453G PFMA 69.90 3.5 4.5 35.7 (2.5) 30.9 NPDMA 29.50 DEAPAA 0.603H PFMA 68.87 3.5 3.0 38.7 (2.5) 188 (20) 0.20 (0.03) 30.4 NPDMA 29.06 PETMP 1.62 DEAPAA 0.453I PFMA 69.20 3.5 3.0 39.2 (2.3) -- 0.15 (0.02) 30.6 NPDMA 29.20 42.4 (1.0)* PETMP 1.00 DEAPAA 0.604 PFMA 70.60 3.5 4.0 37.6 (1.0) -- 0.19 (0.01) 31.0 NPDMA 19.07 39.1 (2.3)** BIS-MA 9.62 PETMP 0.97 DMAPE .285 PFMA 59.00 3 4.0 36.4 (3.0) -- -- 35.3 PDFOMA 15.20 HMDMA 15.20 BIS-EMA 10.00 DMSX 0.60 *Stored 1 week in distilled water at 37° C. Stored 2 weeks in distilled water at 37° C.6A PFMA 78.15 3 2.0 32.3 (3.0).sup.b -- 0.15 (0.02) 34.5 DMDMA 18.49 35.6 (2.4)*** PETMP 3.13 BDMA 0.236B Same as 6A 3 2.0 32.0 (1.6) -- 0.23 (0.01) 34.5 with F-Glass7A PFMA 74.33 3.5 4.0 35.8 (2.9) 165 (29) 0.13 (0.01) 32.9 DMDMA 24.86 PETMP 0.54 BDMA 0.277B Same as 7A 3.5 4.0 35.3 (2.0) 159 (14) 0.16 (0.03) 32.9 with F-Glass*7C PFMA (68.84) 3 2.0 41.0 (1.0).sup.b 232 (9).sup.b 0.17 (0.02) 30.4 DMDMA (29.50) PETMP (0.98) **DHPPT (0.40) DMAPE (0.28)*7D PFMA (69.53) 3 6.0 39.0 (1.0) -- 0.18 (0.02) 30.4 DMDMA (29.79) DHPPT (0.40) DMAPE (0.28)7E Same 3 6.0 36.0 (6) -- 0.21 (0.02) 30.47F Same 4 5.0 41.0 (3) -- 0.18 (0.02) 30.48A PFMA 71.50 3.5 4.5 30.7 (2.5) -- -- 31.6 TMPTHA 27.20 PETMP 1.00 DMAPE 0.308B PFMA 75.50 3.5 3.5 29.8 (1.1) 34.9 TMPTMA 20.60 PDFOMA 2.50 PETMP 1.00 DMAPE 0.30 BHT 0.109A PFMA 69.10 3.5 4.5 35.3 (3.0) 41.0 HFIPMA 21.80 NPDMA 8.40 DMAPE 0.709B PFMA 68.30 3.5 3.0 39.6 (1.2) 0.20 (0.03) 40.6 HFIPMA 21.60 NPDMA 8.30 PETMP 1.10 DMAPE 0.7010A PFMA 68.10 4.0 7.5 37.7 (1.7) -- -- 41.5 OFPMA 22.40 BIS-EMA 7.50 PETMP 1.40 DMAPE 0.6010B PFMA 66.72 3.5 5.0 38.4 (1.8) -- -- 38.3 OFPMA 17.44 BIS-EMA 5.83 NPDMA 8.67 PETMP 0.90 DMAPE 0.4410C Same as 10B 4.0 2.5 40.0 (2.8) 0.21 (0.01) 38.311 PFMA (69.27) 4.5 6.5 40.0 (1) -- 0.17 (0.02) 30.4 HMDMA (28.08) PETMP (1.32) DHPPT (0.58) DMAPE (0.58) BHT (0.17)__________________________________________________________________________ *Fused quartz silanized with A174 and coated with 1% BP used in these formulations **DHPPT = N,N--Bis(2Hydroxypropyl)p-toluidine ***Stored in distilled water for 48 hours at 37° C. .sup.a mean of 5 determinations; 24 hour storage at 37° C. .sup.b standard deviation .sup.c except for composites employing F = Glass, powder was glass silanized with 3methacryloxypropyltrimethoxysilane (A174) and coated with 1 wt % benzoyl peroxide (see Table 4)
It will be obvious to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown in the drawings and described in the specification.
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Dental resin systems prepared from polyfunctional or monofunctional highly-fluorinated methacrylate prepolymers are described. Preferred systems comprise (a) a major amount of a polyfluorinated aligomeric polyfunctional methacrylate such as (PFMA), preferably in combination with a diluent monomer such as 1,10-decamethylene dimethacrylate (DMDMA), methyl methacrylate (MMA), neopentyl dimethacrylate (NPDMA), 1,6-hexamethylene dimethacrylate (HMDMA), etc., or mixtures thereof; and (b) a minor amount of a polyfluorinated monofunctional methacrylate (PFMMA), such as 1,1-dihydropentadecafluorooctyl methacrylate (PDFOMA) as a minor or secondary diluent monomer in a non-hydroxylated bis-GMA resin system. The products are generally useful as hydrophobic dental materials, esepcially as composited (with fillers), sealants and cements.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates, in general, to hydraulic couplings, and specifically to hydraulic couplings used in undersea drilling and production applications. More particularly, the invention involves undersea hydraulic couplings having seal retainers that hold and retain seals between the coupling members. The improved seal retainer of the present invention utilizes pressure actuated metal seals to improve the fluid integrity of the seal retainer and associated hydraulic coupling.
[0003] 2. Description of Related Art
[0004] Subsea hydraulic couplings are old in the art. The couplings generally consist of a male member and a female member with seals to seal the junction between the male and female members. The female member generally has a cylindrical body with a relatively large diameter bore at one end and a relatively small diameter bore at the other. The small bore facilitates connections to hydraulic lines, while the large bore contains the seals and receives the male portion of the coupling. The male member includes a probe section insertable into the large bore of the female member. According to various embodiments of the device, the seals either abut the end, or face, of the male member or engage the male member about its outer circumference. Hydraulic fluid is then free to flow through the female and male portions of the coupling and seals prevent that flow from escaping about the joints of the coupling.
[0005] Optionally, a check valve may be installed in the female member and also in the male member. Each check valve is open when the coupling is made up; however, each check valve closes when the coupling is broken so as to prevent fluid from leaking out of the system of which the coupling is part.
[0006] Application Ser. No. 10/285,062 filed on Oct. 31, 2002 commonly assigned to the assignee of the present invention, entitled “Seal Retainer For Undersea Hydraulic Coupling,” incorporated herein by reference, discloses a seal retainer for use with a female coupling member, wherein the seal retainer contains all seals for the female coupling. The seal retainer may be easily removed and repaired without damage to the female coupling member.
[0007] In higher pressure situations additional seal integrity may be desired to prevent fluid leakage from the hydraulic coupling. Therefore, what is needed is a seal retainer that contains a metal seal that can be pressure energized to prevent fluid leakage in either direction inside the coupling. A copending application filed on the same day as the present application with the same assignee and inventor entitled “Seal Retainer with Metal Seal Members for Undersea Hydraulic Couplings” is directed to the use of press fit or interference fit metal seals and is incorporated herein by reference.
SUMMARY OF THE INVENTION
[0008] The present invention provides an improved seal retainer for an undersea hydraulic coupling that provides higher integrity metal, pressure energized seals while still providing the benefits of removal of seals as a single unit together with the seal retainer. The metal seals are designed to engage both the male probe as well as shoulders inside the receptacle of the female coupling member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.
[0010] FIG. 1 is a section view of the improved seal retainer of the present invention according to a first embodiment.
[0011] FIG. 2 is a section view of a female coupling member with the improved seal retainer according to the first embodiment.
DETAILED DESCRIPTION
[0012] As shown in FIG. 1 , in a first embodiment, seal retainer 10 comprises shell 21 and seal carrier 30 , with central bore 20 extending therethrough. The seal carrier fits together with the shell to form the seal retainer that may be inserted and removed from a female undersea hydraulic coupling member. The seal retainer 10 holds and secures one or more annular seals that are configured to engage the male coupling member.
[0013] In a first embodiment, the shell 21 is generally ring-shaped body with an outer diameter 22 that may be threaded to engage the female coupling member. The shell has first end 28 , second end 45 , first larger inner diameter 23 , second smaller inner diameter 25 , and internal shoulder 27 between the first and second inner diameters. The shell also may include negative or reverse angle shoulder 26 that extends radially inwardly from internal shoulder 27 . Holes 35 may be included in the first end of the shell, and a spanner or other tool may be inserted into the holes to rotate the shell 21 to engage or disengage it from the female member.
[0014] In the first embodiment, the seal carrier 30 is a generally ring shaped body, part of which engages or fits at least partially into the shell 21 . The seal carrier has first end 39 which fits into the shell, second end 29 , first larger outer diameter 42 , second smaller outer diameter 32 , first larger inner diameter 36 , and second smaller inner diameter 34 . In one embodiment, the seal carrier may have negative or reverse angle shoulder 37 between the first larger inner diameter and second smaller inner diameter. The seal carrier also may include outer shoulder 31 between the first larger outer diameter and the second smaller outer diameter.
[0015] In one embodiment, the first end of the seal carrier slides into the first larger inner diameter of 23 of the shell. There may be little or no clearance between the second smaller outer diameter of the seal carrier and the inner diameter of the shell, or there may be a slight interference fit. When the first end of the seal carrier is fully inserted into the shell, the first end 39 may abut internal step 27 of the shell, and first end 45 of the shell may abut outer shoulder 31 of the seal carrier.
[0016] In the embodiment of FIG. 1 , the seal retainer holds third annular seal 60 between reverse angled shoulders 26 and 37 that restrain the seal from implosion into central bore 20 . Third annular seal 60 may be an elastomeric ring with a dovetail cross section, and may have a dovetail interfit between the reverse angled shoulders. The inner diameter of the third annular seal 60 may extend further into the central bore than the smaller inner diameters of the shell or seal carrier, to seal radially with the male member when the male member is in the receiving chamber. O-rings 62 are included on the outer circumference of the third annular seal to form a seal with inner diameter 36 of the seal carrier 30 .
[0017] Seal carrier 30 is preferably made of metal. Machined out of the body of seal carrier 30 is a metal lip seal 64 that extends around the inner circumference. The metal lip seal 64 is machined so that when the probe of the male coupling member is inserted into the female coupling member, the metal lip seal 64 will be forced out slightly causing a press fit or interference fit. The distance the metal lip seal 64 is displaced is preferably around 0.001 inches. Pressurized fluid will tend to try and escape the coupling up along the probe of the male member, or around the outside of seal retainer 10 . Metal lip seal 64 is designed to prevent fluid loss along the probe. If pressurized fluid is attempting to flow up along the probe, it will first fill cavity 66 , which as the pressure builds, will simply work to increase the seal pressure of the metal lip seal 64 against the probe. To prevent fluid flow around the seal retainer 10 , concave metal seal 68 and o-ring 70 are used.
[0018] FIG. 2 shows the seal retainer 10 as shown in FIG. 1 as it is installed in a female coupling member 72 . As can be seen in FIG. 2 , the female coupling member has a receptacle defined by inner diameter 74 for receiving the seal retainer. The female coupling member additionally has shoulders 76 and 78 for contacting end 29 of the seal carrier, as well as seals 68 and 70 . Metal concave seal 68 is machined so that when end 29 is in contact with shoulder 76 , the legs of concave metal seal 68 are in press contact with shoulder 78 so that some slight displacement of the legs of seal 68 occurs. The displacement of the legs of metal concave seal 68 is preferably in the range of 0.001 inches. When the probe of the male coupling member is inserted, cavity 80 will remain. If pressurized fluid attempts to flow around the seal retainer from the male probe, the fluid will fill cavity 80 first causing increased pressure on metal concave seal 68 to further seal off the fluid flow. Vice versa, if fluid from outside the coupling tries to come around the seal retainer and gets past primary seal 70 , the fluid will likewise fill cavity 82 causing additional pressure to further seal off fluid flow using metal concave seal 68 . As will be apparent to others of skill in the art, metal concave seal 68 could be designed to be pressure energized from only one direction using just a lip seal as with 64 .
[0019] As those of skill in the art, not only are there variations to the configurations of the metal seals that may be made, but the invention could be used with only one metal seal, or additional metal seals. The invention, accordingly, should be understood to be limited only by the scope of the appended claims.
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An improved seal retainer for an undersea hydraulic coupling member, which utilizes pressure energized metal seals to maintain fluid integrity. One or more metal seals designed to have a press or interference fit are utilized in such a way that pressurized fluid trying to escape past the seal actually helps to pressure energize the seal to ensure a better seal.
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FIELD OF THE INVENTION
The present invention relates to a spectacle frame, as well as a process for assembling a foot with lugs belonging to such a frame to an organic lens.
Specifically, the frame according to the invention belongs to the type in which two side-arms adapted so as each to be fitted to an individual one of two organic lenses via one of its ends forming a hinge and a bridge adapted to be fitted between the two lenses, a part of the side-arms and/or of the bridge including means of direct fixing to the lenses.
BACKGROUND OF THE INVENTION
Document DE-C-291 548 discloses a type of means for directly fixing a bridge to the edge of a mineral lens.
Another category of frames of the aforesaid type, known as "three-piece frames", is available commercially.
These are frames which do not include a part adapted so as to encircle the periphery of the lenses, and which have therefore been designed so as to meet a desire for lightness and discreetness. The bridge and the side-arms of these frames are fixed to the lenses by screwing through the lenses which have therefore to be drilled for this purpose. Screwing requires recourse to a set of screws, washers, nuts and lock-nuts.
Such frames nevertheless have several major drawbacks, resulting in particular in their not being able to be assembled with lenses other than by a highly experienced and highly skilful optician. As a matter of fact, the choice of the angle at which the drilling is to be performed is critical in order that, once assembly has been carried out, the lenses are properly located in the desired wearing plane; once the angle has been chosen, it is difficult to make it comply with the drilling; finally, the optician must take all precautions to prevent the lens from cracking either during the initial drilling, or subsequently, namely during the operation of tightening the screws after fitting, or even in the course of use, under the effect of the stress exerted on the lens. In the event of breakage, the optician has to fashion a new lens and again devote considerable time and effort to the fixing thereof, and this may give rise to very significant costs. As a result, numerous opticians are reticent to propose such frames. Let us add that these frames have, for the optician, the drawback of entailing a relatively complex and costly assembly device, owing to the diversity of the pieces forming the fixing means.
Coming to the wearer, the placement of the fixing means generates a certain occular nuisance, in particular in the nasal area, owing to the fact that the screws are located within his field of vision. In extreme cases, the wearer may even manifest a convergent squint (wearers exhibiting small pupillary distances).
Finally, spectacles which include such frames are tricky to maintain. Apart from their intrinsic fragility, a problem results from the fact that, in such frames, the screws serving to fix the bridge pass through the lens and through a tab appertaining to the bridge and which is thus applied closely against the internal face of the lens. Dirt slips between this tab and the lens, which dirt is inaccessible but visible from the outside face of the lens. Ultrasound cleaning does not generally allow this dirt to be totally eliminated and the only means of removing it completely is to dismantle the bridge, with the risk of breaking the lens which this entails when dismantling and refitting.
SUMMARY OF THE INVENTION
The purpose of the present invention is to remedy these various drawbacks by proposing a spectacle frame of very low weight, which can be fixed to the lenses by simple means, which any optician can implement, which offers the wearer of spectacles a total visual field and which poses no cleaning problem.
These purposes are achieved in the sense that, according to the invention, the means of fixing of a part of the side-arms and/or of the bridge to the lenses consist in a foot provided with two lugs that are spaced from each other by from around 5 to around 10 mm and are engageable with two blind holes provided in said edge of said lenses, wherein said blind holes do not extend from one face of said lenses to the other, the directions into which the lugs extend, from the respective regions of connection of said lugs with said foot, being divergent. The lenses are therefore no longer drilled.
The foot with lugs may optionally be integral with the part of the side-arms and/or of the bridge.
Advantageously, each of the lugs makes an angle of around 45° with respect to the so-called "principal" direction of the foot in the vicinity of the lug. In this way, the lugs are effectively immobilized in the blind holes.
The term "principal direction" is understood to mean the direction of the tangent to the foot, in the case of a curved foot, and the longitudinal axis of the foot, in the case of a straight foot.
The side-arm part can for example be a joining piece which is integral both with one of the two rotary elements of the hinge and with the foot, the joining piece being perpendicular both to the axis of rotation of the hinge and to the foot.
The side-arm part can also be a joining piece which is integral both with one of the two rotary elements of the hinge and with the foot the joining piece making an angle of between around 80° and around 85° with the so-called "principal" direction of the foot in the vicinity of the joining piece. From the point of view of the wearer of the spectacles which incorporate this frame, the foot is then fixed higher or lower on the edge of the lens than in the previous case.
The bridge part can for example be the end of the bridge itself, integrally secured to, and perpendicular to the foot.
The invention also relates to spectacles which incorporate a frame according to the invention.
The invention further relates to a process for assembling a foot with lugs belonging to a frame according to the invention to an organic lens of spectacles, which comprises the steps consisting:
a) in making a pair of V-shaped blind holes in the edge of the lens, so that the unit formed by the edge part of the lens lying between the blind holes and each of the adjacent walls, the so-called "matching walls", of each blind hole has substantially the same geometry as the foot with lugs;
b) in coating the matching walls of the blind holes with a near-instantaneous setting adhesive;
c) in inserting and then in holding each of the against the matching wall of the blind holes, for the time required for setting;
d) in filling in by means of an adhesive the remaining empty space in the blind holes, between the lugs and the other wall of the blind holes.
Preferably, step d) is implemented around two hours after the end of step c). By virtue of this two stage sticking process, the lugs are effectively immobilized in the blind holes, to the matching wall of which they adhere particularly strongly, even when performing, for example, flexural or tensile movements of the side-arm part and/or bridge part at the corresponding foot.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be further detailed below, with reference to the appended drawings in which:
FIG. 1 is a perspective view of a portion of side-arm of a frame according to the invention, fixed to an edge part of a lens;
FIG. 2 is a schematic sectional view of the unit represented in FIG. 1; and
FIG. 3 is a schematic sectional view of a portion of bridge of a frame according to the invention, fixed to an edge part of a lens.
DETAILED DESCRIPTION OF THE INVENTION
In these figures, identical reference numerals identify identical or similar elements.
FIGS. 1 and 2 illustrate a unit consisting of a side-arm portion of spectacles 1 made of steel or titanium, for example, which is partially folded and pivotably mounted on a cylindrical hinge 2, secured to a joining piece 3. The joining piece 3 assumes the form of a square, the two ends of which are in the shape of arcs of circles, one being adapted to the semi-circumference of the hinge 2 and secured to the latter, and the other being secured to a foot 4. The foot 4 offers, opposite the joining piece 3, a substantially rectangular surface which exhibits a small curvature both in the longitudinal and transverse directions, and a small thickness, relative to its other dimensions. The joining piece 3 is located approximately in the transverse midplane of the rectangle. The foot 4 is provided with two lugs 5 and 6 each of which projects from, and has a width less than, a width of the said rectangle. The lugs 5,6 extend in two divergent directions X--X' and Y--Y', respectively, so as to make an angle A of around 45° with the tangent T to the foot 4 at the joining piece 3. The two lugs 5 and 6 have the form of claws which can have a length of 1 to 2 mm and a width of 0.5 mm, for example. The distance d between the lugs 5,6 is between around 5 and around 10 mm; it can for example be 9 mm. The lugs 5 and 6 penetrate respectively into two blind holes 8 and 9 made in the edge 7 of the lens V, part of which is represented.
FIG. 3 illustrates an assembly similar to that of the previous figures, which differs from them only through the fact that a bridge portion 15 has been substituted for the unit consisting of side-arm portion 1, hinge 2 and joining piece 3 of the previous figures; the bridge 15 is integral with, or integrally secured to, the foot 4 via its ends 17. This figure will not therefore be described in greater detail. In this case, the distance separating the two lugs 5 and 6 is for example 8 mm.
The frame unit, as represented in FIGS. 1 and 2, consisting of two side-arms each provided with a foot with lugs and of a bridge, as represented in FIG. 3, provided with a foot with lugs at each of its ends, is made from a lightweight metal and weighs, for example, no more than three grams.
The invention also relates to a four-step process for assembling a foot with lugs according to the invention to a lens edge. This process will be described by reference to FIGS. 1 to 3.
In the first step, a pair of blind holes 8 and 9 is formed in the edge 7 of a lens V, for example by means of a 0.5 mm diameter drill. Each blind hole is delimited, on the one hand, by a wall 10,11 matching with a respective lug 5, 6 and, on the other hand, by another wall 13,14.
The blind holes 8,9 have a geometry such that the unit formed by the edge part of the lens 12 lying between the two blind holes 8 and 9, on the one hand, and the two matching walls 10 and 11, on the other hand, has substantially the same geometry as the foot with lugs 4 provided with lugs 5,6. In the case represented in FIGS. 1 to 3, the foot 4 has a slightly curved shape. It could also have a straight or even dihedral shape, depending on the shape of the lens to which the frame is applied.
The second step consists in coating the matching walls 10,11 with a quick-setting adhesive such as, for example, an adhesive based on epoxy resin, phenolic resin, cyanoacrylate, etc.
In the third step, the two lugs 5 and 6 are introduced into the blind holes 8 and 9, respectively, and pressed against the matching walls 10 and 11, respectively, of the latter, but without deforming the lugs 5,6. The lugs 5,6 are held pressed against the walls 10,11 for the time required for the adhesive to set, which may for example be 30 seconds.
The fourth step, which is for example implemented two hours after the third step, consists in filling in with the aid of the same adhesive or of a different adhesive the empty spaces between the lugs 5 and 6 and the free walls 13 and 14, respectively, of the blind holes 8 and 9, as seen at 16.
As evident from the above description, the invention affords a spectacle frame which, apart from its lightness, is strong and practically invisible, offers a total field of vision and is readily adaptable to concave or convex organic lenses of any shape, especially round, oval, rectangular or pantoscopic and appropriate to any type of correction such as myopia, hypermetropia, astigmatism or presbyopia, as well as to multifocal lenses.
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The spectacle frame comprises two side pieces each adapted to be secured to one of two organic lenses by hinging one of its ends, and a bridge adapted to be secured between the two lenses, a part of the side pieces and/or the bridge comprising elements for directly securing them to the lenses. The securing elements are adapted to engage a portion of the cut-out edge of the lenses over a length of approximately 5-10 mm.
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BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to a novel system consisting of a laundry treatment machine such as a washing machine, washer-dryer or dryer provided a housing which includes a stamped sheet metal bottom panel and of a pedestal which includes lateral frame and/or housing components and a support surface for receiving the laundry treatment machine. Moreover, the invention relates to a method of making such a system.
[0002] European patent specification EP 0,943,721 A1 discloses a laundry treatment machine manufactured by a so-called frame construction. It involves assembling a sheet metal bottom panel, two L-shaped angular frame elements and a cross into a support frame for receiving the functional components of the machine and which is thereafter enclosed by covering panels such as a front wall, side walls and a lid.
[0003] German patent specification DE 198 32 675 A1 discloses a pedestal consisting of a box-like sub-structure on which a laundry treatment machine may be positioned. It is intended to increase the working height of the machine and to provide an ergonomic improvement for the user.
[0004] Moreover, German utility model DE 203 02 572 U1 discloses a pedestal with a drawer for a washing machine . In this case, the edges and corner areas of the surfaces are structured as U-shaped profiles or pipes of rectangular cross-section to ensure the required stability.
[0005] From German patent specification DE 196 31 639 A1 a system of stackable kitchen appliances and kitchen furniture is known. In this case, tubular reinforcements are used which defined the coupling sites for any further appliance or furniture.
[0006] Since there is little demand for such pedestals, their manufacture is relatively dear in view of the fact that the costs of their tools have to be apportioned to low quantities. Also, their structure must provide the stability necessary for the weight of 100 kg of a washing machine.
OBJECT OF THE INVENTION
[0007] It is, therefore, an object of the present invention to provide a system of the kind referred to which while economical provides structural stability.
[0008] Another object of the invention is to provide a novel method of making such a system.
[0009] Other object will in part be obvious and will in part appear hereinafter.
BRIEF SUMMARY OF THE INVENTION
[0010] In a preferred embodiment, the object is accomplished by a system of the kind referred to which is provided with a pedestal including a stamped sheet metal bottom panel of predetermined configuration and by a laundry treatment machine provided with a bottom panel of a substantially similar or complementary configuration.
[0011] The method of producing the system is accomplished by stamping the bottom panels for the pedestal and for the laundry treatment machine by the same stamping or clicking machine.
[0012] The advantages to be derived from the practice of the invention are the result from the fact that components are being used for manufacturing the pedestal which in terms of their stability have been proven in connection with washing machines. In addition, because of the large number their manufacturing costs are relatively low.
[0013] In an advantageous embodiment of the invention the bottom panel of the pedestal is made of sheet metal which is thinner than the sheet metal used for bottom panels of laundry treatment machines. In this manner it is possible, in addition to the savings derived from using the same tools for bottom panels of both laundry treatment machines and the pedestals, to generate further savings as a result of lower material costs for the pedestals.
[0014] In a useful embodiment, the pedestal is provided with a drawer at its front side.
DESCRIPTION OF THE SEVERAL DRAWINGS
[0015] FIG. 1 is a perspective view of the entire system consisting of a pedestal and a washing machine positioned thereon;
[0016] FIG. 2 depicts the pedestal of FIG. 1 with pulled-out drawer;
[0017] FIG. 3 depicts the pedestal of FIG. 2 without the drawer; and
[0018] FIG. 4 depicts the bottom sheet metal panel of the pedestal or washing machine as an individual component.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] The household washing machine 1 shown in FIG. 1 is positioned on a pedestal 2 and connected therewith in a manner to be described. The structure of such a washing machine is sufficiently known from European patent specification EP 0,943,721 A1 and is, therefore, neither shown nor described in any detail. Its housing is manufactured as a frame structure, the frame including, among other components, a sheet metal bottom panel. In the context of the invention, it is only the manufacture of this sheet metal bottom panel 3 which is important and which shown in detail in FIG. 4 . Initially, it is severed by a punching or clicking operation as one piece from a coil of sheet metal (not shown) and provided with the required cut-outs 4 and openings 5 . Thereafter, recesses 6 and protrusions 7 are formed in a multiple step stamping operation by a stamping process by one or more stamping tools. In this manner, a circumferential margin 8 is formed in the sheet metal bottom panel 3 . In addition, stamped nuts 9 for the reception of machine feet 10 (see FIGS. 1 and 2 ) are formed during this process.
[0020] For manufacturing the pedestal 2 shown as a single component in FIGS. 2 and 3 a sheet metal bottom panel 3 . 1 is used which is subjected to a similar shaping process as the sheet metal bottom panel 3 of the washing machine 1 . Since it need not be quite as stable or sturdy as the bottom panel of the washing machine 1 the bottom panel 3 . 1 may be made of thinner sheet metal. A unitary body 11 constitutes a further component of the pedestal 2 . It constitutes the two side walls 12 and a supporting surface 13 for the washing machine 1 . This component, too, is initially cut by punching from a coil of sheet metal and provided with a pattern of openings the function of which will be described hereinafter. Thereafter, the side walls 12 are folded, and a marginal strip 14 , 15 is folded down from the front as well as rear of the supporting surface 13 . In their overlapping area 16 , these marginal strips are joined by clinch connections 17 . The body 11 is connected to the bottom panel 3 . 1 by blind rivets 18 . Thereafter, a flat panel (not shown) is screwed to the rear of the body 11 to close it.
[0021] The marginal strips 14 of the side walls 12 are bent inwardly by a further chamfering operation. In this manner, they form abutments 19 for threadedly connecting two lateral sheet metal fastening panels 20 which in turn are each provided with a telescoping rail 21 . The rails 21 serve to receive a drawer 22 shown in FIG. 1 in its inserted state and in FIG. 2 in its withdrawn state. The structure of such a drawer 22 is generally known and is not, therefore, described here in any detail. It is to be mentioned, however, that the front panel 23 of the drawer 22 is dimensioned such that is it completely covers the front side of the pedestal 2 .
[0022] In its front section, the telescoping rail 21 is fastened to the chamfer 19 of the pedestal as well ass to the fastening panel 20 . To this end, both components are provided with consecutively positioned bores of which FIG. 3 only shows bore 24 at the chamfer 19 . The added fastening of the telescoping rail 21 at the pedestal 2 provides for a defined alignment of the front panel 23 relative to the edges of the pedestal 2 .
[0023] For erecting the system, feet 10 usually screwed into the bottom panel 3 of the washing machine 1 are removed therefrom and threaded into the stamped nuts in the bottom panel 3 . 1 of the pedestal 2 . Threaded pins (not shown) are screwed into the stamped nuts 9 in the bottom panel 3 of the washing machine 1 . Thereafter, the washing machine 1 is aligned relative to the support surface 13 such that the threaded pins protrude into corresponding bores 25 in the surface 13 . To connect the washing machine 1 to the pedestal 2 each threaded pin is secured by a nut screwed onto the pin in the interior of the pedestal 2 . The numerous bores 25 are provided for the accommodation of various types of machines.
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A system for stacking a laundry treatment machine provided with a bottom panel of predetermined three-dimensional configuration onto a pedestal or the like provided with a support surface of a complementary three-dimensional configuration. The bottom panel is preferably made of sheet metal of a predetermined thickness or gauge, and the support surface is made of a sheet metal of lesser thickness or gauge.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. application Ser. No. 11/530,310 filed Sep. 8, 2006, now U.S. Pat. No. 7,800,812, which in turn claims the benefit of U.S. application Nos. 60/596,198 filed Sep. 8, 2005, 60/721,731 filed Sep. 28, 2005, and 60/597,162 filed Nov. 14, 2005, each of which is incorporated herein by reference for all purposes.
BACKGROUND OF THE INVENTION
Light valves have been in use for more than sixty years for the modulation of light. As used herein, a light valve is defined as a cell formed of two walls that are spaced apart by a small distance, at least one wall being transparent, the walls having electrodes thereon, usually in the form of transparent, electrically conductive coatings. The cell contains a light-modulating element (sometimes herein referred to as an “activatable material”), which may be either a liquid suspension of particles, or a plastic film in which droplets of a liquid suspension of particles are distributed.
The liquid suspension (sometimes herein referred to as “a liquid light valve suspension” or “a light valve suspension”) comprises small, anisotropically shaped particles suspended in a liquid suspending medium. In the absence of an applied electrical field, the particles in the liquid suspension assume random positions due to Brownian movement, and hence a beam of light passing into the cell is reflected, transmitted or absorbed, depending upon the cell structure, the nature and concentration of the particles, and the energy content of the light. The light valve is thus relatively dark in the OFF state. However, when an electric field is applied through the liquid light valve suspension in the light valve, the particles become aligned and for many suspensions most of the light can pass through the cell. The light valve is thus relatively transparent in the ON state. Light valves of the type described herein are also known as “suspended particle devices” or “SPDs.” More generally, the term suspended particle device, as used herein, refers to any device in which suspended particles align to allow light to pass through the device when an electric field is applied. Light valves have been proposed for use in numerous applications including windows, skylights, and sunroofs, to control the amount of light passing therethrough or reflected therefrom as the case may be. As used herein the term “light” generally refers to visible electromagnetic radiation, but where applicable, “light” can also comprise other types of electromagnetic radiation such as, but not limited to, infrared radiation and ultraviolet radiation.
The SPD is laminated between two pieces of glass or plastic to form a sandwich which is sometimes called SPD Glass or SPD Plastic, and which can be further used to form a glass or plastic window. With such SPDs forming a window, the amount of light passing through the window can be finely controlled based upon the characteristics of the electricity passing through the SPD. The degree to which something reduces the passage of electromagnetic radiation is known as opacity. When referring to windows, changes in opacity is often noted as a change in a windows tinting, its light transparency or transparency and each of these terms may be equally be used to mean the same.
Such SPDs are now being installed into glass so that the amount of light passing through the glass can be finely controlled based upon the characteristics of the electricity passing through the glass. At least one method by which such glass and thus its opacity or light transparency may be controlled is described by Malvino, in U.S. Pat. Nos. 6,897,997 and 6,804,040 collectively referred to as the Malvino patents. But a device envisioned by Malvino, while suitable for the manual control of a small number of co-located windows, is not scalable nor does it provide the automated intelligence to actively and dynamically control environments of more than a few windows such as in an automobile, marine vehicle, train or aircraft, to as much as a residential or commercial building or a skyscraper of such SPD windows.
The Malvino patents provide the basis for driving SPD glass by varying voltage at a fixed frequency which will cause the glass to lighten toward clear or to darken so as to block most light passing through it. That device is capable of mapping the non-linear characteristics of SPD into a linear range of values that could be thought of as setting the glass from say 0 to 100%. The range is broken down into a small discrete set of settings for perhaps 6 different opaqueness levels and 6 specific resistor and capacitor combinations are built into the implementation and are manually selected to set the proper voltage for the associated degree of tinting. Through that implementation, a linear manual control, such as a slide switch or a rotating dial may be attached to the Malvino controller to directly vary the amount of light allowed through the glass at any time.
The Malvino patents review the use of a few fixed frequencies at which to drive an SPD. As described, driving the device at a lower frequency tends to have a slight lower energy utilization curve with regard to the power needed to drive the SPD. Frequencies in the range of 15 hertz to 60 hertz were discussed. There is a serious potential problem with the aforementioned controller operating the SPD when driven by these frequencies. It is possible that the SPD will “sing” and be heard as a tone in the B-flat range by being driven by a fixed frequency within that range. An SPD controlled window typically consists of SPD-capable material in the form of a clear Mylar coated with SPD emulation, placed in between two pieces of glass. The SPD is basically sandwiched and held in place by glass on both sides. If 50/60 Hertz current travels through the sandwiched SPD, in some cases, the Mylar will start to vibrate in resonance with the driving frequency and may be heard by people near the window as an annoying hum.
A considerable issue in the wide-scale worldwide deployment of SPD windows, is on how residential and commercial buildings will be wired up to allow some “central intelligence” to operate the individual windows. Today, there is no concept of running wires to windows from some control room in the building. It is not desirable to introduce a new requirement for building wiring in the introduction of SPD glass around the world, since thousands of installation people would need to learn and understand new building wiring requirements. Yet, if any other techniques are employed to “wire” each window to the “central intelligence”, it must require little or no training, and be a relatively low cost so as not to make the use of SPD glass prohibitive.
SUMMARY OF THE INVENTION
The invention relates to a wirelessly enabled apparatus and associated mesh networking software installed in large arrays in order to dynamically control the “skin” of residential and commercial buildings throughout the day in order to absorb or reflect sunlight in such a manner as to dramatically reduce the energy consumption of such buildings. The integration of a mesh network lowers the cost of deployment of such control by permitting the individual devices that control one or more windows, to act as a relay point in moving control signals from intelligent control points in a Building Skin Control System to the individual controllers or sets of controllers which will effect the desired changes. The invention further relates to a Suspended Particle Device control apparatus and associated network installed in large arrays in order to dynamically control the glass windows of residential and commercial buildings throughout the day in order to absorb or reflect sunlight in such a manner as to dramatically reduce the energy consumption of such buildings. The use of a hierarchical distribution system over a LAN or WAN reduces the time to transmit commands from a central intelligence point, the Master Building Control Point, to all window controllers in a structure to set individual windows to a specific level of opaqueness.
The device described herein corrects for the “singing” problem by providing the option of driving the SPD at a variable frequency in the low frequency range rather than a single fixed frequency. Optionally, in lieu of using a continuously variable SPD driving frequency, the Controller may randomly drop or phase shift several cycles per second. The change/shift is not enough to be visibly noticeable but it would eliminate the “ringing effect”. As will be seen below, the system according to the invention scales from the single-window environment to a building with a size beyond that of the currently largest in the world, Taipei 101 in the Xin-Yi district of Taipei, with over 32,000 windows.
This invention provides for a range of SPD control far beyond that previously in existence. The “Scalable Controller” a.k.a. “SC” of this invention adds intelligence that greatly expands the capabilities of prior controllers. As in prior implementations, one to several pieces of glass may be controlled by a single controller, where several is a relatively small number such as 8 and each piece of glass is hardwired to the controller. The Scalable controller further supports a setup phase whereby the user may configure the relationship between manual external control or several individual manual controls and which window/windows are to be controlled from that manual setting. In a setting of four windows under the Scalable Controller, where the windows are referred to as A, B, C and D, a user may configure the SC so that windows AB are controlled as a single window and CD as another, or ABC is controlled as a single window and D as another, or ABCD is controlled as a single window or, ABCD are controlled as 4 separate windows.
This system coordinates the settings of each of the windows in a building in an intelligent manner from a central intelligence point known of the Master Building Control Point. It will make intelligent decisions based on many factors including real time events, as to the proper amount of visible light to permit to flow through each window in order to take best advantage of the solar heating effect.
Enhanced capabilities of the SC over prior inventions provide for full control of all operational parameters which effect the characteristics of a SPD. This type of control exists in each SC to optimize SPD performance by power utilization or switching speed potentially taking into account external temperature, while controlling the haze and clarity.
The flexibility of the SC and its networking capabilities also support the display of textual messages or special light tinting sequences as part of a multimedia presentation. Such a multimedia display could change windows along the facade of an office building in time to the changes in perhaps Christmas Music during the holiday period. A scaled-down version of such a system could provide for a moving textual display across small SPD pixels sitting in a box on a desktop. These diverse applications reflect the flexibility and importance of this invention.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be described with respect to a drawing in several figures, of which:
FIG. 1 is a diagram showing an SPD window controller under manual adjustment from a single external device.
FIG. 2 is the controller of FIG. 1 with the addition of a photocell or other photosensor to detect the brightness of sunlight shining on the window under control.
FIG. 3 creates the Intelligent Controller from FIG. 2 by introducing a microprocessor to perform a number of different functions in support of more sophisticated controller capabilities as well as Scalable Network operations of controllers. In addition to the photocell or other photosensor additional inputs from sensors expand the data which the Scalable controller may use to make decisions on how to change window opacity.
FIG. 4 shows the Intelligent Controller with a plurality of manual inputs that are coupled to one or several window panes that are under the direct control of the controller as set up by the user via a set up procedure in the control software. A single manual input may control one window or, two, three or four at one time as if it were a single piece of SPD glass. More then one manual input may be used to control the same set of glass in order to support manual controls that operate from different points in the same room.
FIG. 5 shows different combinations of four-window panes in this example, and how the set up software allows any combination of sets of individual panes to be treated as a single pane of glass.
FIG. 6 shows one of the earliest packet switching or mesh networks in which data may be sent along alternate paths through intermediate nodes in order to reach a destination point. This is an example of the 4-node Arpanet in 1969, the precursor to today's Internet. Host computers sent data to other Host computers in this network and utilized the services of the Interface Message Processor (IMP) to move data packets to other IMPs which were not destination point but would further relay packets toward the IMP directly connected to the desired destination Host.
FIG. 7 shows a more advanced packet switched meshed network in which specific processing applications operate on the same computer that is running the packet switching software thereby combining the functions of Hosts and IMPs in the earlier Arpanet systems. Increases in microprocessor power allowed these functions to be combined onto a single platform. This is an example of a Radio Paging Network application utilizing the Data Link Handler (DLH) protocol created by the Inventor to convert isolated Citywide radio paging (beeper) systems, also known as Paging Terminal Nodes (PTNs), into a nationwide network capable of alerting someone wherever they are located in the country instead of just a single city. The Arpanet and Internet utilize formalized routing protocol specifications such as the Routing Information Protocol (RIP) to dynamically maintain a list of best routes to a destination at each node. DLH utilizes a proprietary routing protocol to maintain a list of primary and alternate routes. The proprietary DLH network was eventually replaced with the Radio Paging Industry standard Telocator Network Paging Protocol (TNPP) protocol which the Inventor helped to create and Chaired the Industry committee to promote the use of this protocol for more than 11 years. TNPP was used along with a manufacturer-specific proprietary routing protocol to maintain the best and alternate paths to each destination node.
FIG. 8 shows a Scalable Controller network consisting of the Intelligence Controller of FIG. 3 integrated with a radio transceiver (XCVR) to send packets of data to other transceiver equipped Scalable Controller (CTL) nodes. Routing data similar to the Internet RIP, maintains a list at each Controller node of the best next node to receive data on the path to the destination node. Unlike the wired network of FIGS. 6 and 7 , the radio network of FIG. 8 may sometimes properly receive data addressed to a different node than that which received it. In this case, the received data is ignored/dropped by the node which is not the next node along the optimal path to the destination.
FIG. 9 shows an example of a network of FIG. 8 where a Building Control Point is connected to one of the nodes of the network. The BCP is a data processing site to determine which portions of a building are to be automatically set to a specific opacity at any moment of the day or night. The Data Processing system may optionally be connected to the Internet and to a remote central monitoring service which oversees the operations of the SPD Building Skin Control System on behalf of many building owners.
FIG. 10 shows an example of a redundant Master Building Control Point (MBCP) consisting of a primary MBCP and a secondary MBCP in the network to insure that the entire system continues to operate normally even if the primary MBCP should fail. If the primary MBCP should fail, the secondary MBCP will take over its functionality so that the entire system continues to operate normally.
FIG. 11 shows how different areas of a building would have different types of Hierarchical Control Points to oversee the operation of Scalable Controllers in certain portions of a building.
FIG. 12 is a Hierarchical mapping of Control Points showing how commands generated at the highest level Control Point are logically distributed to lower level Control Points that distribute the commands to more and more elements at lower hierarchy levels.
FIG. 13 shows how the Master Building Control Point interfaces with an Intelligent Energy Control System (IECS) via a computer interface utilizing the widely used Extensible Markup Language format referred to as XML.
FIG. 14 shows how the path of the Sun across the sky changes how the sunlight falls on the windows of a building throughout the day. The Sun path changes slightly each day of the year as the Earth rotates around the Sun. For any latitude and longitude on the planet, the path that is traversed is well known.
FIG. 15 shows five controllers each controlling twenty-four panes.
FIG. 16 shows the letter “E” formed by a 5 by 7 pixel array with a border.
FIG. 17 shows a lighting effect in which each pane differs from its neighbor by a few percent.
FIG. 18 shows a controller sending a command to a decoder which in turn communicates commands to windows.
FIG. 19 shows two Scalable Controllers (SCs) consisting of the Intelligent Controller of FIG. 1 integrated with a LAN interface so that they can send packets of data to a Master Control Point (MCP) located on the LAN.
FIG. 20 shows that when LANs has reached its maximum capacity, due to cable length, a Bridge may be introduced in order to add another LAN segment to extend the size of the LAN.
FIG. 21 shows how to further extend the size of a local network when the maximum number of LAN segments and Bridge/Repeaters has been deployed.
FIG. 22 shows the logical connections that form a hierarchy of control points in order to reduce the point to point communication loading on the MCP to issue commands to all SCs in a building.
FIG. 23 shows how the Master Control Point, which provides the central control intelligence for all of the individual windows in a structure, can connect to an external Intelligent Energy Control System via a computer interface using the widely used Extensible Markup Language format referred to as XML. The external system can modify its operations knowing where windows have been changed. The external system may receive sensor input through the MCP and may command the MCP to modify the setting or some or all windows under its control. The MCP also has the option of changing the operation of the windows under IECS command if better algorithms have been developed on the IECS and the External system starts sending the proper control commands.
FIG. 24 shows the major subsections which comprise the Scalable Controller.
FIG. 25 shows one of the typical three-dimensional tables of data that is programmed into the controller to operate it. Such table provide information on the interaction of three variables that together control the operation of SPD based glass.
DETAILED DESCRIPTION OF THE INVENTION
With the incorporation of a Microprocessor into the Scalable Controller, the capabilities and flexibility of the device are expanded dramatically for use both in a standalone environment as well as being a data point in a sea of such controllers which, under such intelligent control, can dynamically modify the skin of an office building to provide unprecedented control over its energy usage. Even in the standalone environment, the SC can be programmed with the intelligence to reduce energy usage in the room where it is being used. The SC may be put into an automatic mode instead of being under manual control and can operate as described below.
Although the same functions may be achieved in several ways, in the implementation described herein, the end user has the ability to set the latitude, longitude, window orientation from North, and window angle from vertical into a suitable data processing program. This program creates a profile that can be downloaded into the SC which uses the setup data to determine the location on the earth of the window(s) under control and thereby, for each window, its angle from the sun at any time of the day. A time/date clock operates in the SC to drive its window(s) based upon the time of day, day of year, and the location on the planet. At 1:00 PM on July 2nd in Manhattan, N.Y., the windows directly facing the sun would be set to the maximum opaqueness while those angled away from the sun would have reduced opaqueness and those on the opposite side of the building might be totally clear. As the sun crosses the sky, each window changes according to the built-in profile. Yet at 1:00 PM on July 2nd in Sydney Australia, those windows facing the sun will be clear, so that the building's heating system requirements may be reduced by utilizing the sun to heat windows directly facing the sun, while windows on the opposite side of the building would be turned dark so as to keep heat trapped in the building. A photocell connected to the SC will provide external sensor input so as to allow the SC to further fine tune the current opaqueness based upon current cloud and weather conditions. Sidereal information has been well known and calculable for centuries and may thus be profiled into the SC device itself. Weather conditions that might block the sun are random real-time events.
Although such Intelligent control permits several windows to operate autonomously, in a larger-scale implementation, it is desirable to put entire segments of building windows under a coordinated set of controls. In relatively large types of environments, rather than using a profile of individual windows, it is possible to perform more real-time data processing and to make more intelligent decisions of the opacity of every segment of a building at any point in time. The SC of this invention is capable of expanding so as to operate in such a mode.
This system virtually eliminates all building wiring issues to put all SPD windows under a central control. Each Scalable Controller is outfitted with a low-power, low-data-rate, limited-range, radio transceiver. These radio transceivers are capable of communicating on a point-to-point basis to one or more radio transceivers located within other Scalable Controllers in a 3-dimensional space around each controller. The SC microprocessor is further outfitted with mesh networking software. Such types of software have been in existence in various incarnations for a long period of time. The radio transceivers send specially formatted packets of data back and forth between each other. Some packets contain data which is used to operate the mesh network itself while other packets contain sensor data or window control information. Routing control packets are one type of mesh control packet which is sent. Each SC can be thought of as a “node” in the mesh network. The routing information is used to leave information at each individual node to indicate an available “route” to move data from a window controller to another intermediate window controller along a path to a “Hierarchical Control Point (HCP)” or from an HCP through intermediate window controllers on its way to a specific individual window controller. An HCP is the location of a special data processing node, as opposed to a window controller node, which is capable of coordinating the changing of the opaqueness of windows for some segment of a building. There may be several Office Control Points (OCP), Section Control Points (SCP), Region Control Points (RCP), Floor Control Points (FCP), Multi-floor Control Points (MCP) and a single Building Control Point (BCP) located in typical building environment. A single Control Point might exist in a small implementation while all types of Control Points may exist in a very large-scale implementation. The use of additional Control Points reduces communication overhead in the mesh network and decreases the time delay between the time a window opaqueness modification command is sent and when it is acted upon at individual windows. In this instantiation of the invention, any window SC can become a Control Point via a command sent from the Building Control Point. Although a Building Control Point is an Intelligent Data Processing System, the lower hierarchical control points have a relatively small set of fixed commands and operations which can easily be handled at the Microprocessor at any window SC. In the largest-scale implementation of the Scalable Controller Network, the BCP can inform the Multi-Floor Control Points (MCP) to change the settings of each window on all floors; the MCP will distribute this request to each of the FCP's; the FCP's will distribute the request to the RCP's; the RCP's will send the command to SCP's; and the SCP's will forward the commands to OCP's which will command each window controller in an office to execute the required change. Because of the expansion to multiple nodes at each level of the hierarchy, commands may be simultaneously sent within different non-overlapping areas of the network where they may pass through intermediate nodes with no or little queuing delay, thus having the request executed throughout the building in a seemingly simultaneous fashion.
Typically, a window controller is not in direct radio communication with the location in the building where a HCP might be located. But every window controller will typically be within radio communication of several other window controllers. The mesh networking software permits a data packet to be sent from a source node to any neighboring node that is along a path which eventually leads to the destination node, through a series of hops through intermediate nodes. Because of the multiple paths that exist between nodes, data can typically be routed around areas of the network that might be temporarily undergoing radio interference. Data retransmission and acknowledgments during point-to-point communications insure that data is not dropped by one node until the next node in the network has accepted the data being sent. If such acknowledgment is not received, a node may send its data onto an alternate path to the destination. If a segment of the radio network should become isolated, a packet hop count insures that packets which will never reach their ultimate destination are eliminated from the network. End-to-end acknowledgments let the source and destination nodes recognize when data must be retransmitted in its entirety because it may have been dropped due to a particular radio failure creating isolated subnetworks. Reporting processes built into the Building Controller monitor the nodes in the network, gather interconnectivity data, and take into account the window controller addresses to assist the installer in insuring that all nodes are capable of communicating with the Hierarchical Control Points. Where it might be found that some portion of the overall network is isolated from another portion, special nodes may be installed in a geographical area between existing segments of the network, in order to provide a bridging point for data to move from one network segment toward the other. There should typically be at least two nodes to bridge isolated segments together. The bridges are nothing more than window Scalable Controllers that are not connected to any SPD window.
The Scalable Controllers may be equipped with various types of sensors that may be used in more finely controlling the energy usage in a building. A photocell may be placed onto each SPD glass and connected to its SC. The Building Control Point “BCP” may command all the SCs to periodically send sensor data to the BCP or the BCP may periodically poll each of the SCs to read photocell and other sensor data. Through an initial system configuration procedure at the BCP, it is made aware of the configuration of the building, the compass direction in which windows face, the latitude and longitude of the building, the angle at which each window is from the vertical, and the location of unique node and window addresses. Input from photocells throughout the building allow the BCP to utilize voting techniques to determine the best areas of the building in which to increase or decrease opaqueness in order to reduce the overall building energy requirements for heating and air conditioning. If a readable compass and glass angle detector is installed at each SC, the process of modeling the building to establish more precise control of each window, is simplified, by directly providing this configuration information.
The BCP allows the system operator to establish special overrides for portions of the building at certain times of the day and days of the year. This might be utilized to specify a region of the building undergoing glare from reflections from other buildings or natural features in the area. The override features would allow a normally clear window to perhaps to be darkened for some period to eliminate the glare onto that portion of the building. So some regions of a building might be under automatic control while other segments of the building may be under special override conditions at the time. A complex combination of each control may be in effect at one time.
Many “Green” buildings already incorporate an Intelligent Energy Control System such as the Honeywell Enterprise Buildings Integrator (EBI). These types of systems operate/monitor/control the building HVAC system, circulation of fresh air, elimination of building odors, control of electric usage, and reduction of energy requirements to unoccupied areas. These top-of-the-line systems also incorporate building security, monitoring and access control, asset tracking, fire and smoke detection and even control fire doors and public announcement systems. This invention extends the capabilities of these sophisticated systems in a manner that was never possible before. These system may now effectively control the skin of the building dynamically during the day, optimizing the use of the sun along with the movement of heat and air conditioning around the building. The combination of both systems provides a level of efficiency of an even higher level than that capable of standalone windows or BCP controlled windows, since it directly controls multiple subsystems in a building in a coordinated fashion.
In this instantiation of the invention, the BCP will provide an interface to an external system to provide additional sensor data to the external system and to allow the external system to request adjustments to light levels around the building in a high-level form. One of the preferred high-level forms in which an external system will represent sensor data and requests to adjust light levels to the BCP and the BCP will represent responses to such data and requests through this interface is known as XML. XML is an abbreviation for Extensible Markup Language and is a widely used open standard for organizing and exchanging structured documents and data between two computers. A computer to computer link over which data is transferred in the XML format is often referred to as an XML link or an XML interface. The BCP takes requests from the XML link, interprets them and executes them by sending the proper commands through the hierarchical network to effect the changes requested by the external Intelligent Energy Control System (IECS). When operating in this mode, the automated controls of the BCP are bypassed. A periodic “heartbeat” transfer of XML command/responses over the BCP/IECS link insures that the two systems remain in sync and that they coordinate operations. In the event the heartbeat is lost, the BCP can fall back to its automated mode and operate the building independently until the IECS system comes back on-line.
This invention utilizes low-cost, low-power, limited-range Radio Transceivers co-located with each window controller device, to form a large scale wireless network between all of the windows in a residential or commercial building. Windows are typically within 10 meters of each other within buildings, so limited range transceivers are perfectly suited for this environment. The microprocessor-driven software within each controller operates the local application functions of the controller while at the same time executing radio packet switching type software used to send messages from source nodes to destination nodes in a building, even though the source and destination node are not in direct communication with each other because of their distance from each other. The data which are to be moved from the source to the destination are sent to a transceiver which is reachable from the source node, and toward another radio transceiver that is reachable along a path which will eventually get the packetized data to the desired destination.
The technique of moving messages from source computers to destination computers through intermediate points in a multiply-connected array of computers was originally referred to as Packet Switching and was first characterized in the Arpanet, the precursor to the Internet in 1969. FIG. 6 , which represents the Arpanet's 4-node network operational in December 1969, could potentially send a packet of data from Host 161 to Host 163 , by handing the data packet to Interface Message Processor (IMP) 61 , which might forward it to IMP 62 , and to IMP 63 where it is handed to destination Host 163 . If IMP 62 finds that the link to IMP 63 is not functioning for some period of time, the same data from Host 161 to 163 could be handed over to IMP 64 to forward the data to IMP 63 instead of using the failed direct link. The concept in a packet-switched network is to locate alternate paths to get the packet to the ultimate destination point even if some individual communication paths are out of service. Some packet networks utilize fixed routing tables to define alternate data paths in the event of link failures and have algorithms to determine when primary or alternate paths are to be utilized. Other packet networks have dynamically updated routing information that is periodically updated between adjacent nodes in order to continually maintain a list of the best route to any ultimate destination in the network.
With improvements in hardware and software, the separation of a Host (applications processor) and a packet switching network of nodes (the Interface Message Processors—IMP's) was no longer necessary. The 1980 ITT-DTS Faxpak facsimile Store-and-Forward packet switching system integrated an application which provided compatibility between different speed fax machines of the time, with a message passing network which allowed messages to always be delivered locally instead of via what (in those days) were more expensive calls over long-distance lines. The Wide Area Paging network in FIG. 7 ran an application that permitted any node in the network to accept a paging message (phone number) specified through a dial-in telephone call, a text message received from an operator, or a message received from a remote node, to a paging message that would be encoded and transmitted at a destination node. The packet switching software that operated at the same nodes, directed paging application packets to be dropped off at the proper destination node or nodes to page a person in multiple cities.
Packet networks typically operated with dedicated communication circuits between nodes in different cities. More recently, the same multi-path packet switching technique has been deployed into networks of radio transceivers, utilizing radio links in lieu of wired links between pairs of nodes. These radio packet switching systems have become known as mesh networks. Unlike the 2-D wired communication circuits as in FIG. 7 , the radio devices in a mesh network permit point-to-point communications within a 3-D region of each node. In an office environment, where each window may represent a node, windows within a few feet left or right of a particular window can be thought of as potential intermediate nodes, as well as windows that are potentially a few floors above or a few floors below a particular window.
In this instantiation, a header packet in each transmission packet specifies the source node address, destination node address and the address of the next hopping point along the path to the destination. This data is transmitted in three dimensions when it is time for this Scalable Controller to transmit information to another point in the network. Many receivers will detect interference in the data they receive, and will ignore the received data. Several other receivers may receive the packet but with transmission errors. Only the node to which the correctly received packet is addressed will keep the packet, analyze it and will decide if the data item is to be forward toward another intermediate node to the final destination or if the packet is to be handled by the application software at this node.
To allow multiple commands to be outstanding and be executed at different points in the network simultaneously, a logical hierarchical structure is introduced into the network. Certain network nodes are designated as Hierarchical Control Points (HCP) that only forward data toward lower level Hierarchical Control Points. Ultimately, the lowest level HCP logically forwards data only to a subset of all Scalable Controllers in the network. This logical configuration allows a single command to be branched out in multiple commands and each of those commands to further expand to even more multiple commands, thereby controlling the maximum number of nodes with the minimal number of control messages at the highest level. So a command to make all windows clear in a segment of a building would be initiated at the highest level node and be handed down to lower levels nodes that understood where this command needs to be sent in order to effect the desired windows in the building.
On the other hand, sensor data that was considered as an urgent data item to which to reach, captured at the individual Scalable Controllers, would be directed to higher and then higher levels of HCPs until the data item reaches the highest level HCP.
Turning to FIG. 1 , we see an SPD window controller 2 under manual adjustment from a single external device 1 . It controls a window 5 .
FIG. 2 shows the controller of FIG. 1 with the addition of a photocell 10 to detect the brightness of sunlight shining on the window 5 under control.
FIG. 3 creates the Intelligent Controller from FIG. 2 by introducing a microprocessor 3 to perform a number of different functions in support of more sophisticated controller capabilities as well as Scalable Network operations of controllers. In addition to supporting the photocell 6 or other photosensor as the non-Intelligent controller of FIG. 2 , additional inputs from sensors 8 expand the data which the Scalable controller may use to make decisions on how to change window opacity.
FIG. 4 shows the Intelligent Controller with a plurality of manual inputs 1 that are coupled to one or several window panes 51 - 54 that are under the direct control of the controller as set up by the user via a set up procedure in the control software. A single manual input may control one window or two, three or four at one time as if it were a single piece of SPD glass. More than one manual input may be used to control the same set of glass in order to support manual controls that operate from different points in the same room.
FIG. 5 shows different combinations of four-window panes in this example, and how the set up software allows any combination of sets of individual panes to be treated as a single pane of glass. In a setting of four windows under the Scalable Controller, where the windows are referred to as A, B, C and D, a user may configure the SC so that windows AC are controlled as a single window and BD as another, or BCD is controlled as a single window and A as another, or ABCD is controlled as a single window or, A, B, C, D, are controlled as four separate windows.
FIG. 6 shows one of the earliest packet switching or mesh networks in which data may be sent along alternate paths through intermediate nodes in order to reach a destination point. This is an example of the 4-node Arpanet in 1969, the precursor to today's Internet. Host computers sent data to other Host computers in this network and utilized the services of the Interface Message Processor (IMP) 61 to move data packets to other IMPs 62 , 64 which were not destination points but would further relay packets toward the particular IMP 63 directly connected to the desired destination Host 163 .
FIG. 7 shows a more advanced packet switched meshed network in which specific processing applications operate on the same computer that is running the packet switching software thereby combining the functions of Hosts and IMPs in the earlier Arpanet systems. Increases in microprocessor power allowed these functions to be combined onto a single platform. This is an example of a Radio Paging Network application utilizing the Data Link Handler (DLH) protocol created by the Inventor to convert isolated Citywide radio paging (beeper) systems, also known as Paging Terminal Nodes (PTNs), into a nationwide network capable of alerting someone wherever they are located in the country instead of just a single city. The Arpanet and Internet utilize formalized routing protocol specifications such as RIP to dynamically maintain a list of best routes to a destination at each node. DLH utilizes a proprietary routing protocol to maintain a list of primary and alternate routes. The proprietary DLH network was eventually replaced with the Radio Paging Industry standard TNPP protocol which the Inventor helped to create and Chaired the Industry committee to promote the use of this protocol for more than 11 years. TNPP was used along with a manufacturer-specific proprietary routing protocol to maintain the best and alternate paths to each destination node. A paging message originating at Paging Terminal Node (PTN) B 72 might be passed to other PTNs 73 , 74 until reaching a PTN 71 which is in turn coupled with antennas which pass digital information in RF form to a pocket paging receiver 171 .
FIG. 8 shows a Scalable Controller network consisting of the Intelligent Controller of FIG. 3 integrated with a radio transceiver (XCVR) to send packets of data to other transceiver equipped Scalable Controller (CTL) nodes. Routing data similar to the Internet RIP, maintains a list at each Controller node of the best next node to receive data on the path to the destination node. Unlike the wired network of FIGS. 6 and 7 , the radio network of FIG. 8 may sometimes properly receive data addressed to a different node than that which received it. In this case, the received data is ignored/dropped by the node which is not the next node along the optimal path to the destination. Each controller 81 , 82 , 83 , 84 has a controller, a microprocessor, and a radio transceiver.
FIG. 9 shows an example of a network of FIG. 8 where a Master Building Control Point (MBCP) 90 is connected to one of the nodes of the network. The MBCP 90 is a data processing site to determine which portions of a building are to be automatically set to a specific opacity at any moment of the day or night. The Data Processing system may optionally be connected to the Internet 91 and to a remote central monitoring service 92 which oversees the operations of the SPD Building Skin Control System on behalf of many building owners.
FIG. 10 shows an example of a redundant Master Building Control Point (MBCP) consisting of a primary MBCP and a secondary MBCP in the network to insure that the entire system continues to operate normally even if the primary MBCP should fail. One MBCP (shown as a data processor) is connected to node 81 and a second MBCP (also shown as a data processor) is connected to a node 87 . If the primary MBCP should fail, the secondary MBCP will take over its functionality so that the entire system continues normal operations.
FIG. 11 shows how different areas of a building would have different types of Hierarchical Control Points (HCPs) to oversee the operation of Scalable Controllers in certain portions of a building.
FIG. 12 is a Hierarchical mapping of Control Points showing how commands generated at the highest level Control Point are logically distributed to lower level Control Points that distribute the commands to more and more elements at lower hierarchy levels. There may be several Office Control Points (OCP), Section Control Points (SCP), Region Control Points (RCP), Floor Control Points (FCP), Multi-floor Control Points (MCP) and a single Building Control Point (BCP) located in typical building environment. A single Control Point might exist in a small implementation while all types of Control Points may exist in a very large-scale implementation. The use of additional Control Points reduces communication overhead in the mesh network and decreases the time delay between the time a window opaqueness modification command is sent and when it is acted upon at individual windows. In this instantiation of the invention, any window SC can become a Control Point via a command sent from the Master Building Control Point. Although a Master Building Control Point is an Intelligent Data Processing System, the lower hierarchical control points have a relatively small set of fixed commands and operations which can easily be handled at the Microprocessor at any window SC. In an intermediate size implementation of the Scalable Controller Network, the MBCP can inform the FCPs 96 , 99 ; the FCPs will distribute the request to the RCPs 97 , 100 , 101 , 102 ; the RCPs will send the command to OCPs which will command each window controller in an office (not shown for clarity) to execute the required change. Because of the expansion to multiple nodes at each level of the hierarchy, commands may be simultaneously sent within different non-overlapping areas of the network where they may pass through intermediate nodes with no or little queuing delay, thus having the request executed throughout the building in a seemingly simultaneous fashion.
FIG. 22 shows the logical connections that form a hierarchy of control points in order to reduce the point-to-point communication loading on the Multi-Floor Control Point MCP to issue commands to all SCs in a building. In the example shown, the MCP sends commands to two Floor Control Points (FCP) that are optimally placed on separate LANs. Simultaneously, each FCP can relay the command to Section Control Points (SCP) that in turn may transmit the commands to Office Control Points (OCP). Each OCP may simultaneously relay the commands it has received to the one or more SCs for which it is responsible. Ultimately all of the SCs will have received the required commands, but the hierarchical structure reduces the total number of data transmissions across the entire network to reach each SC from the MCP.
FIG. 13 shows how the Master Building Control Point 110 interfaces with an Intelligent Energy Control System (IECS) 111 via an XML interface 112 . FIG. 23 shows in more detail how the Master Building Control Point 204 , which provides the central control intelligence for all of the individual windows in a structure, can connect to an external Intelligent Energy Control System 210 via an XML link 209 , so that the external system may receive sensor input through the MBCP and may command the MBCP to modify the setting or some or all windows under its control.
FIG. 14 shows how the path of the Sun across the sky changes how the sunlight falls on the windows of a building throughout the day. The Sun path changes slightly each day of the year as the Earth rotates around the Sun. For any latitude and longitude on the planet, the path that is traversed is well known.
Another embodiment of the invention transforms an array of windows into a part of a multi-media display. Office buildings are often decorated in a manner as to enhance the appearance of the city in which it is located. In Houston, for example, many of the large buildings are outlined in rows of small lights on the perimeter of each building so as to form an outline of the cities skyline each evening. During holidays, many buildings will turn specific lights on and off in the building late at night when the building is primarily empty so as to display some pattern associated with the holiday. For example, during Christmas, a cross may appear in the windows of a large building. Or diamond shape patterns may be displayed at different floor levels of a building and at adjacent buildings as part of the winter season.
This embodiment extends the MBCP functions so that it may direct SPD windows to be part of a video presentation. The controllers are unaffected when adding this capability because they already have the ability to change any pane of glass under their control to any setting from clear to dark or any setting in between under manual or under automated control from the MBCP. So a special, non-energy-efficiency-related application may exist in the MBCP to operate the windows in a special manner as desired by the building operator.
Textual Messaging Mode
There are two modes of operation, although they may both operate simultaneously. The first mode is to use SPD windows to form a textual display of messages. In its simplest application each pane of SPD glass represents a single pixel of information. The size of the window pane and the matrix size making up a letter defines how far away the user must be from the window to be able to clearly read the letters formed. In some cases a square box of 4 or 9 (2.times.2 or 3.times.3) windows may be controlled as one in order to increase the size of an individual pixel. Each controller receives a command from the MBCP to set its pixel to on or off or at some degree of shading. Using a set of 48 windows, a 6.times.8 pixel array may form any letter or punctuation and include a one-pixel border around each letter.
The MBCP may operate in another mode where the message(s) to be displayed is given to it via an external system rather than from local consoles on the MBCP. The MBCP will support several interfaces for message entry. This includes an XML type command set between the MBCP and an external system. The command set may operate over a LAN connection, serial port, infrared port or other physical method. The MBCP may be programmed with a sequence of letters/words/messages to display, with timing information, and with a starting pixel location. Changing the window/pixel settings at the specified rate will provide the sensation that the text message is scrolling across the windows. This is done, for example, by removing one vertical column of pixel data on the left side of the display by shifting the setting of one window to the right over to the one window on the left. The column of pixels at the right-most window is for the next letter to be displayed. This provides a smooth scrolling right to left. In a similar manner the letters may also be scrolled left to right for languages written in the opposite direction. The starting location of each row of text may be specified so that messages may start at any floor of windows or several floors at the same time.
Logic in the MBCP will also provide for other textual display features taking advantage of the capabilities of SPD Glass. For example, letters may appear upside down and be changed right side up. They could perhaps be rotated vertically along any of the rows that make up each letter. The pixels can start at clear and the letters can be formed by varying the darkness of each pixel individually or from top to bottom or bottom to top for some interesting special effects. Words can be brought into display in the same manner. Darkening columns of pixels left to right and right to left meeting in the middle of a sentence or starting in the center and radiating out to the left and right. Or different starting columns may be selected and the pixels may radiate out in one direction or both as the letters darken. There is no limit as to the combinations that can be made to make the generation of the display more interesting than just displaying a letter at a time at a given intensity. Of course any of these special display methods will be available over the XML interface so external devices may drive arrays of SPD Glass.
Although this example reviews the use of SPD Glass on an office building as a means of displaying messages, this may be scaled down to smaller applications, depending upon the size of each pane of glass or pixel. For example, messages could be scrolled across an atrium of SPD glass just above the heads of people standing under it. Or, if very small panes of glass are used, small moving displays of SPD glass could be created.
Video Mode
The SPD windows on a structure may also be looked at as a sea of pixels each capable of being set to any shading level from 0% to 100%, the ends of the range being thought of as Off and On. There is an endless combination of different light level settings across each pixel in a large array, to provide many random and well-structured visual effects that would entertain people viewing such a display. A large number of preprogrammed sets of sequences may be defined and stored in the MBCP. Each sequence may provide some special effect seen across the glass. Sequences may be defined such as:
Flash from all dark to all light
Start from all dark and lighten to clear slowly
from left to right
right to left
top to bottom
bottom to top
center to edge in a increasing squares manner
edge to center
Checkerboard pattern
And many many others
The MBCP will support many means of initiating a sequence and the ability to store away ‘scripts’ of preprogrammed sets of sequences. The MBCP will be able to be driven via the serial port or LAN connection of a PC. It can also support an external device that is actually an array of buttons and switches, where the combination of a switch setting and pressing a button initiates a pre-programmed sequence. In this way an operator may “play” sequences in time to external music, just as a laser light show operator uses a similar type panel to initiate pre-programmed lighting effects that are in tune with the music playing. An elaborate array of new sequences may be established off-line and sent to the MBCP from an external system at any time. Some of these external sequences may be later stored in the MBCP and called up by reference number rather than having to repeatedly download the sequence from an external device. For further integration in a multi-media environment, when the window array is set to full dark, video projectors could potentially be utilized to display moving images across the SPD glass. This sequence would be requested when external video projectors are commanded to start displaying video data.
The array of pixels associated with one instantaneous state of a sequence, is set to specific levels via the sending of wireless commands to each of the necessary controllers to set its associated pixels to the proper setting. The wireless command may be received directly from the radio interface at the MBCP or via any intermediate node(s)/controller(s) in the array (mesh packet network) when the controller of a particular pixel is not in direct communication with the MBCP.
The ability of the MBCP to provide visual special effects across window arrays is further enhanced through a set of special interfaces that are supported by the MBCP. The MBCP can be made to appear as a controllable lighting system to lighting industry standard DMX based Intelligent Control System. These systems already have support for creating and saving scripts of special effects in support of multi-media lighting shows.
X.10 Control of SPD Windows
The controllers of the invention may operate over a wireless network in support of automatic remote control in a large building environment. But in smaller environments, such as a residential project having perhaps 16 windows, the wireless control solution may be overly expensive in some situations. In order to address this situation, there is another variation of the scalable controller. Instead of integrating the controller with a radio transmitter and receiver as described above, this invention provides an interface to the above controller which is capable of receiving X.10 control signals over a 110 VAC/220 VAC power line. A United States patent that is now expired covered the X.10 communication protocol. Yet, because of how long it has been in existence, the number of compatible products that exist, the easy availability of X.10 controllers that send control signals over the power line, and their low cost, an X.10 compatible interface is desirable. FIG. 18 shows a controller 181 transmitting X.10 signals, sending a command to an X.10 decoder 182 which in turn communicates commands to windows 183
The X.10 interface option will be placed onto the controller circuit card that is operating one or more panes of glass. Each controller will operate via a direct power connection to the 110 VAC/220 VAC power line. Up to 256 windows may be controlled in this environment. Each window controller will be assigned an X.10 Letter (Home/Network ID) and Number Code (Device ID). When the window controller sees its address on the powerline bus, it will then look for a command signal such as ON, OFF, DIM UP, DIM DOWN. An ON signal will be executed at the controller as a signal to set the window to full Dark. An OFF signal will be interpreted as setting the window to full Clear. The controller maintains the current setting of the window under its control. A DIM UP command will slowly increase the darkness of a window from 0% toward 100% and a DIM DOWN command will slowly decrease the darkness making the window clearer. Any X.10 device capable of sending these four signals to any of the 256 possible X.10 addresses will now be capable of controlling any SPD window. X.10 controllers currently exist to send these four signals under manual control or to program a computer to send commands at particular times of the day. This will provide a very simple means of local control of a small number of SPDs. A similar interface will exist for support of several wireless replacements to X.10 devices, Z-Wave, Insteon, and 802.11.15 ZigBee.
FIG. 15 shows 5 controllers each controlling 24 window/panes. These window panes may physically be aligned so that A and B are next to each other and E and D are directly below them. This would form an 8.times.12 pixel array. Commands from the MBCP will be sent via its local transmitter, M, into the wireless mesh network. Because of the mesh networking aspects of the controller network, if the MBCS is capable of communicating directly with controller D but finds it cannot directly communicate with controller B, it may route command data through node controller C to command B to set its pixels. To control the settings at node A, the command may for example go via the path M,D,E.A or M,D,B,A or M,C.B,A.
FIG. 16 shows show the letter “E” formed in a 5 by 7 pixel array of darkened windows, with a border at the left and top having a width of a single window/pixel.
FIG. 17 shows a lighting effect in which each pane differs from its neighbor by a few percent.
It will be appreciated that this invention provides for a range of SPD control far beyond that previously in existence. The “Scalable Controller” a.k.a. “SC” of this invention adds intelligence that greatly expands the capabilities of prior controllers. As in prior implementations, one to several pieces of glass may be controlled by a single controller, where several is a relatively small number such as eight and each piece of glass is hardwired to the controller. The Scalable controller further supports a set up phase whereby the user may configure the relationship between manual external control or several individual manual controls and which window/windows are to be controlled from that manual setting. In a setting of four windows under the Scalable Controller, where the windows are referred to as A, B, C and D, a user may configure the SC so that windows AB is controlled as a single window and CD as another, or ABC is controlled as a single window and D as another, or ABCD is controlled as a single window or, ABCD are controlled as 4 separate windows, as mentioned above in connection with FIG. 5 .
Although such intelligent control permits several windows to operate autonomously, in a larger scale implementation, it is desirable to put entire segments of building windows under a coordinated set of controls. In relatively large types of environments, rather than using a profile of individual windows, it is possible to perform real-time data processing and make more intelligent decisions of the opacity of every segment of a building at any point in time. The SC of this invention is capable of expanding so as to operate in such a mode.
When the SC is in manual mode, it utilizes inputs from the room occupant to control the precise setting of the opaqueness of the SPD glass or plastic it is controlling. There is a range of different manual input devices that might be used. Switches, rheostat-like devices, or capacitance-type devices that have no moving parts but can sense the touch of a finger, for example, my all be utilized. But the SCs may also receive commands sent to it via a Local Area Network to which the is connected. The SC allows for the plug in of an LAN card so that it may receive commands from elsewhere in the network to control functions to be performed. Multiple LANs may be connected via Repeater/Bridges to increase the size of the physical area of building windows that is being covered. When the maximum length LAN has been reached, a router can be deployed to connect independent LANs to each other in the creation of a wide area network capable of reaching every SC in the building. The purpose of this wide area network is so that each SC may receive commands that are initiated from a central intelligence point, the Master Building Control Point (MBCP), where a data processing system is making decisions as to the optimal setting of each window. The MBCP is capable of taking in data from sensors that are collocated with SCs by polling for their data, and from other inputs that may be read through the network it is connected to, utilize latitude and longitude information, time of day, day of year, and other facts in order to make decisions how to optimally set the current opacity levels across the building. The MBCP may then send commands through the network to each individual window to select the optimal setting.
The Scalable Controllers may be equipped with various types of sensors that may be used in more finely controlling the energy usage in a building. A photocell may be placed onto each SPD glass and connected to its SC (see FIGS. 2 and 3 ). The Master Building Control Point “MBCP” may command all the SCs to periodically send sensor data to the MBCP or the MBCP may periodically poll each of the SCs to read photocell and other sensor data. Through an initial system configuration procedure at the MBCP, it is made aware of the configuration of the building, the compass direction in which windows face, the latitude and longitude of the building, the angle at which each window is from vertical, and the location of unique node and window addresses. Input from photocells throughout the building allow the MBCP to utilize voting techniques to determine the best areas of the building in which to increase or decrease opaqueness in order to reduce the overall building energy requirements for heating and air conditioning. If a readable compass and glass angle detector is installed at key SCs, the process of modeling the building to establish more precise control of each window, is simplified, by directly providing this configuration information.
In order to reduce the overall load on the backbone of the LANs and to allow commands to be executed truly simultaneously across the network, a hierarchy of Intelligent Control Points may be created. The control points could be nothing more than individual SCs that are commanded by the MBCP to act as relay stations on behalf of the MBCP. At the highest level of the hierarchy, the Master Building Control Point exists that makes intelligent decisions as to the current settings of opaqueness at all points in a building of SPD glass. Depending upon the size of the implementation, there are several levels of hierarchy. The Master Control Point sends opaqueness modification commands to one or more of the Hierarchical Control Points that in turn communicate with several lower level Hierarchical Control Points and eventually to each of the individual SCs for which it is responsible. Such a multi-level distribution of control reduces the volume of data packets traversing the LAN on which the Master Control Point exists and hands off the command distribution to each of the local LANs thus reducing the load on the Master and on the backbone network. It also allows for commands to be executed more quickly than if each had to be sent directly from the Master Control Point, since each Hierarchical Control Point is performing the distribution of commands for the Master on each of its local LANs. Therefore commands are sent simultaneously across multiple LANs instead of serially. This allows a very large number of Suspended Particle Devices to be changed more quickly and simultaneously.
In this instantiation of the invention, the MBCP will provide an XML interface (as shown in FIG. 13 ) to an external system to provide window tinting information and additional sensor data to the external system and to allow the external system to request adjustments to tinting levels around the building or adjust room lighting under its control. The MBCP takes requests from the XML link, interprets them and executes them by sending the proper commands through the Hierarchical network to effect the changes requested by the external Intelligent Energy Control System (IECS). When operating in this mode, the automated controls of the MBCP can be optionally bypassed, rather than using the derived information to command all windows to set in an optimal way. Instead, the commands are generated based upon the XML messages that are received from the IECS. Aperiodic “Heartbeat” transfer of XML command/responses over the MBCP/IECS link, insures that the two systems remain in sync and coordinating operations. In the event the heartbeat is lost, the MBCP can fall back to its automated mode and operate the building independently until the IECS system comes back online. Optionally the MBCP can remain in direct control of window tinting providing the IECS with data to help augment its operations.
FIG. 19 shows two Scalable Controllers (SCs) 191 , 192 consisting of the Intelligent Controller of FIG. 1 integrated with a LAN interface 194 so that they can send packets of data by means of a LAN 193 to a Master Control Point (MBCP) 192 located on the LAN.
FIG. 20 shows that when each of several LANs 201 has reached its maximum capacity, due to cable length of in this example, a Bridge 202 may be introduced in order to add another LAN segment to extend the size of the LAN. This would be the first method used in a structure to be employed to connect more controllers to a Master Building Control Point 204 which is controlling the settings of all of the SCs. This figure also depicts a Hub 205 which provides direct connectivity to individual SCs 206 rather than multiple SCs hanging off a shared wire. The connection between the Hub 205 and the individual SCs 206 may be wired or could be wireless. Using wireless LANs reduces the amount of building wiring that must be done to connect every Scalable Controller to the network that will provide connectivity to the Master Control Point 204 containing the building control logic.
FIG. 21 shows how to further extend the size of a local network when the maximum number of LAN segments and Bridge/Repeaters 202 has been deployed. A Router component 207 is added which allows new and independent LAN segments to be connected to the Router 207 . The Router 207 recognizes when data has been directed to a LAN address that is on a different LAN, and it then takes that data from the receiving LAN and resends it over the correct LAN where the destination address is located. Mapping tables tell the Router 207 what ranges of addresses each LAN handles. SCs located all over a large building are connected to the closest LAN in order to receive messages from the Master Building Control Point 204 located on the same or a remote LAN or from the Hierarchical Control Point located on the same LAN. This allows the MBCP to instantaneously change the opacity setting of any window in the building.
It will be appreciated that what has been described above greatly expands the Malvino patents in terms of scalability. But the SC also expands the basic functionality of the Malvino patents by providing a means of control of SPD far beyond that envisioned in those patents. The microprocessor-driven device can control the modulation of the voltage, setting of any desired operating frequency and/or setting of waveform characteristics to at least one suspended particle device (SPD) thereby controlling the light valve opacity characteristics of the device, as well as a means of manually controlling the modulating means where manual control information is read by the microprocessor and said microprocessor then adjusts modulating means based upon the setting of the manual control. There can be a plurality of manual control devices and/or a plurality of individual SPDs hardwired to the microprocessor driven device. There can be a setup procedure where the relationship between which one of a plurality of manual control devices is to be used to directly control the SPD opacity of one or more of a plurality of hardwired SPDs so as to act as if it is a single SPD. There can be a means of externally controlling the modulating means through digital commands received over a communications channel. There can be a radio transmitter and receiver, using point-to-point radio communications to transmit and receive data at neighboring microprocessor driven devices, where remote radio receiving device interprets the header of a packet of data sent by the transmitting device and only processes the receiving data if necessary as determined from the packet header data. If the header data at the receiving microprocessor specifies that said receive data is meant for a different microprocessor driven device that is not directly in communication with the receiving device, the receiving device shall resend the data packet toward another microprocessor driven device or node, by consulting an on-board dynamically updated Routing Table to send the data further along in the aforementioned network via additional intermediate hopping points. Once said packet of data reaches its final destination point, it is processed by application software at that final destination.
Many different types of packets may be sent through the network, some of which are used to maintain the network itself, others which move statistical data through the network and others which move application data such as Light Valve commands, through the network. One type of network packet may distribute instantaneous routing information that will be used at each node to assist in the determination of the best next route to be used to move this packet toward the destination node. Another type of packet will contain SPD Glass control command for a remote node, asking the remote node to change the local Light Valve to a particular setting.
The system may incorporate an interface to a Local Area Network (LAN) to connect a Master Building Control Point, a microprocessor-driven device which makes intelligent decisions regarding what opaqueness should be set at an individual window, and sends commands to other parts of the system over the LAN. The LAN may be wired via Thinnet, Thicknet, twisted pair, optical fiber or other wired LAN means, or wireless using any variant of IEEE 802.11, or IEEE 802.15 or other wireless LAN means. The LAN may be bridged to another LAN to extend restrictions on bus length or the number of devices connected to one bus. The LAN may be extended using a router in order to connect to other LANs over a much larger area of a residential or commercial building that can be reached by a single LAN in order to communicate with the Master Building Control Point attached to the local or wider area network.
The controller may run a particular set of software that enables it to perform its normal functions in addition to becoming an “Intelligent Control Point” on the LAN referred to as the Hierarchical Control Point. This device is capable of communicating with every one of the devices in a hierarchy.
The system may automatically change the Light Valves under its control, based upon the physical orientation of the SPD on the earth, the latitude and longitude of the SPD, the day of the year and the time of the day. The microprocessor will support a profile of data which is derived from off-line processing of the orientation of the window in space at every moment of the year so that optimal Light Valve settings may continuously be made in order to reduce energy utilization in residential and commercial environments using window based SPDs.
If manual override operations are used to override automated operations, after a specific period of time automated operations may resume. Automated operations may be resumed when a room occupancy sensor does not show any movement in a room for a specific period of time. The system may support a small number of fixed profiles for daytime and night time opacity settings and a switch to manually set which profile is currently in effect. There may be two profiles and the manual switch may be labeled Summer and Winter. There may be four profiles and the manual switch is labeled Summer, Fall, Winter and Spring.
In the system, optimal Light Valve settings may be derived in real time in lieu of using a predetermined profile of information. Such real-time calculations might be performed at the Master Building Control Point.
A device comprising the same electronics as a controller that operates an SPD may not connected to any SPD but may only be used as an intermediate hopping point to move data between other fully SPD operational devices, utilized in spots where radio coverage is poor where fully operational devices are unable to communicate directly with each other. This hopping-point device may be placed in an otherwise dead spot between other devices, to act as a bridge between the other devices.
In the system, messages may flow through a hierarchy of specialized nodes and not from any node to any other node in the network. At the highest level of the hierarchy, a Control Point exists that makes intelligent decisions as to the current settings of opaqueness at all points in a building of SPD glass. Depending upon the size of the implementation, there are several levels of hierarchy. One of these Building Control Points communicates several lower level control points so that each may simultaneously act upon the command to modify the Light Valve setting at a controller. The lower level control point may further distribute the command to another lower level of control points to further spread the command to the largest number of points in the quickest time so that the windows may be activated as quickly as possible.
In the system, messages may flow through a hierarchy of Intelligent Control Points located on the same or different LANs than the Master Control Point. At the highest level of the hierarchy, a Control Point exists that makes intelligent decisions as to the current settings of opacity at all points in a building of SPD glass. Depending upon the size of the implementation, there are several levels of hierarchy. The Master Control Point sends opacity modification commands to one or more of the Hierarchical Control Points which in turn communicate with several lower level Hierarchical Control Points and eventually to each of the individual controllers within its realm of control. Such a multi-level distribution of control reduces the volume of data packets traversing the LAN on which the Master Control Point exists and hands off the command distribution to each of the local LANs thus reducing the load on the Master and on the backbone network. It also allows for commands to be executed more quickly than if each had to be sent directly from the Master Control Point, since each Hierarchical Control Point is performing the distribution of commands for the Master on each of its local LANs. Therefore commands are sent simultaneously across multiple LANs instead of serially. This allows a very large number of Suspended Particle Devices to be changed more quickly and simultaneously.
The SC may modulate the frequency across a variable range, occurring simultaneously with the varying of Voltage driving the SPD. Driving the device over a variable frequency can eliminate a potential for the glass to “sing” (generating an audio tone) that would otherwise annoy human individuals in the same room.
A scalable controller may include a sensor circuit to detect a drop in the current flow through the SPD. This would be indicative of a breakage in the SPD. In this event the SC sends the MBCP a “glass breakage detection” message to denote the event. The MBCP in receiving the alarm is capable of determining which window this came from and will request human intervention through any of a number of different means. This might include one or more radio paging messages sent over the Internet, a short message for one or more cell phones sent over the Internet, calling a central station monitoring facility and generating a synthetic voice message, sending a message over the Internet to a monitoring service specifically overseeing the SPD-glass building control, among other means. The MBCP maintain hysteresis logic so that if flooded with breakage detection messages at any one time, multiple alerts are not generated, unless they are not responded to in a given period of time. The MBCP is capable of turning off the glass-breakage detection logic at an SC for any period of time, so as to avoid being flooded with messages from entire sections of the building, after the alert has been acknowledged.
For all SPD applications including automotive, marine, aerospace and architectural, the controller of this invention can drive the SPD in more sophisticated ways than in the Malvino patents.
First, various waveforms can be used rather than a single waveform.
Second, the duty cycle can be varied, to conserve energy.
Within the controller, two or more electro-optical lookup tables can be stored to support multiple types of SPD.
The manner of driving the SPD can be adjusted based upon external temperature.
And, power can be dynamically managed to optimize power consumption.
The Malvino U.S. Pat. Nos. 6,897,997 and 6,804,040 provided for a basic method of driving SPD based material so that it changes from its clear to dark state or to various levels of opacity in between. These basic patents do not address the full operational parameters of SPD or their control. The microprocessor-centric SC provides for an unprecedented level of fine and optimized control of SPD through several methodologies, algorithms and feedback mechanisms that this enhanced controller patent describes.
The Malvino '997 and '040 patents were concerned with the creation of some set of electronics that would allow SPD-based material to change state. But detailed studies of the nature of SPD reveals that there are several features of SPD other than opacity that must be taken into account to properly control SPD-based windows. And there are many variable factors which control these features.
The main feature of SPD is in its ability to move from a clear state to a dark state and back again or to any intermediate opacity level, based upon the frequency and AC voltage level applied. But other important features to control are switching time, haze, clarity, possible singing or humming of the SPD laminated between two pieces of glass or plastic, and power consumption. There are many parameters whose settings affect these features. These are AC voltage, frequency, frequency tolerance, temperature, wave form, wave phase, duty cycle, thickness of the SPD, the manufacturer of the SPD and sometimes which production run itself within one manufacturer. The simple circuits of the Malvino U.S. Pat. Nos. 6,897,997 and 6,804,040 are incapable of factoring in all of these parameters to provide the desired performance of the SPD.
Different applications of SPD will require optimization of some manner of operating a SC. In building applications that are targeted at energy efficiency the SC will emphasize those functions aimed at energy conservation. Switching speed would be traded off for energy efficiency. In an automobile the vendor may wish opacity changing time, also referred to as glass switching time or glass switching speed, to remain constant regardless of the exterior temperature of the vehicle. The SC can insure a lower switching speed by driving the SPDs at a higher frequency when the outdoor temperature is very low at the expense of utilizing more power.
FIG. 24 shows the logical structure of an embodiment of the invention. This is an enhanced controller not only in its ability to become part of a larger coordinated network of controllers, but it the enhanced intelligence of each individual node in its control of SPD.
The Command and Control portion of the controller receives commands from an external source (such as an optional A/D type device like a dimmer switch for example) or other microprocessors over a communications link, to set the light opacity level of SPD Glass to a particular level. The SC may utilize sensors through its A/D interface to determine the external temperature to take this into account to optimize either switching time or power consumption, whichever is of more importance to the user. A particular shape wave form is set up by the wave generation logic which modulates the required amount of power at the optimal frequency to switch the glass. To reduce the power being utilized to maintain the SPD at a particular opacity level, the duty cycle of the waveform utilized is reduced. Algorithms built into the software of the SC take into account the goal which is to be achieved and adjust the setting of the factors mentioned to provide the desired goal. The SC has full flexibility to adjust all performance affecting parameters in a particular environment.
The controller has a series of internal 3-dimensional tables similar to FIG. 25 , which map various operational parameters against others in order to know how the changing of one factor or two factors will affect the third. For example, the table might define the proper voltage and frequency required for absolute levels of light transmission. Another such table would describe the relationship between switching time and frequency for a given amount of power. A third table would provide a model of switching time and frequency for a given temperature. A fourth table would evaluate switching time and frequency for a given temperature.
Using algorithms built into the intelligent controller it may make trade-offs to optimally operate SPD according to the goals that are programmed into its memory. If the maintenance of switching time at less than 2 seconds from dark to clear is desired, then these algorithms will pull data from these tables to increase the frequency of the AC signal, increase the voltage and provide extra power in order to provide a specific level of opacity for a particular manufacturer's SPD. If in another instance, power consumption was the factor for optimization, the SC would operate the SPD at a lower frequency and adjust the voltage accordingly in order to achieve absolute levels of opacity, where the reduced power consumption would be at the expense of a switching speed of perhaps 8 seconds instead of 2.
This data is repeated for each manufacturer of SPDs so that the controller may make proper decisions based upon the particular SPD being utilized. There may be a day when industry standardization will insure that all SPD reacts in exactly the same repeatable way across manufacturers and across production runs from one manufacture, but until the industry can achieve this level of quality control across different manufacturing processes, multiple tables which model performance must be preprogrammed into the tables of the controller. But the end result is that the controller is a universal controller for all SPD applications.
The set of tables stored in the controller are typically created off-line through laboratory experimentation of each manufacturer's SPD. The resultant data is stored in the tables of the controller or may be downloaded into the controller over its communication channel.
In some implementations of the controller some of the three-dimensional tables will be collapsed to two dimensions as the third factor is not one measured or under the control of the particular model of controller. For example, a basic model of controller may not utilize a temperature sensor and will operate continually under the assumption of a fixed operating temperature. One of the sets of tables in the controller is known as the EO (Electro-Optical) table. This table is ordered by opacity at 0% (dark) to 100% (clear). Each entry contains the optimal frequency and voltage to set a particular manufacturer's glass to the given opacity level. If temperature is not going to be considered in the operation of this version of the controller, the EO table remains two-dimensional.
In addition to using its algorithms and internal tables to set the various parameters to control the SPD, the controller can dynamically change its parameter settings based upon measurement and feedback from sensors connected to its A/D inputs. For example, a light source and photocell or phototransistor or other photodetector may be used to shine a specific intensity light through the changing SPD and to a photocell which will detect the actual light level. The EO table being used to switch the SPD to a particular opacity level may not have a temperature component in its entry. But the controller can measure actual switching time by measuring how long it takes for the glass to reach the opacity level requested, because its light/photocell logic can measure when the actual opacity level has been achieved. Knowing the time, the controller algorithms can determine a better frequency and voltage to operate the glass to reduce the switching time to the desired level. The measuring devices are used in the creation of a feedback loop to auto-adjust operational parameters.
The intelligent controller is able to further reduce the amount of power consumption of SPD to values lower than that achieved by operating the SPD at an optimal frequency and voltage for a given opacity level at a given temperature. The controller may change the duty cycle of the power output to not keep the SPD under constant AC power. Logic in the controller can reduce the number of complete wave form cycles being generated over a given period of time. So if ‘m’ cycles would normally occur in time ‘t’, every other cycle could be ignored and power shut down in those cycles, to achieve a 50% duty factor. In general the goal is to only keep the power operating only ‘n’ out of every ‘m’ cycles in order to reduce power. At some point there will be a visible flickering of the SPD noticed. Experimentation derives another three-dimensional table which specifies the lowest allowable duty cycle for a given opacity level against a third parameter such as operating temperature.
Experimentation and an analysis of the three-dimensional graphs of operational parameters and their resulting features, reveal other mixed operating modes by taking advantage of aspects of different graphs. Reasonable switching speeds of 2 seconds dark to clear at room temperature can be achieved at 60 Hz and 20-100 volts AC. More optimal energy performance is achieved below 60 Hz, perhaps better at 30 Hz, without causing flickering in the SPD. Higher frequencies (400 Hz) can switch the SPD much faster but use more power to effect the switching. The controller takes advantage of these factors when optimizing for switching speed by shifting to a higher frequency during the transition from one opacity level to another then reducing the frequency to the lower allowable range to maintain the opacity setting at low power.
It will be appreciated that one skilled in the relevant art may readily devise myriad obvious variants and improvements upon the invention without undue experimentation, none of which depart in any way from the invention and all of which are intended to be encompassed within the claims which follow.
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A scalable apparatus and a network environment dynamically changes the light transparency of a single SPD device, a small number of SPD devices or thousands of such SPD devices installed in windows in automobiles, aircraft, trains, marine vehicles, residential homes, commercial buildings and skyscrapers. A scalable apparatus and a network environment dynamically changes the light transparency of a single SPD device or thousands of such SPD devices in the presentation of a multi-media special effects display. Textual messages, graphical images and simulated motion effects are driven. Such scalable apparatus being capable of driving and using several operational parameters of SPD materials such as frequency range, AC voltage and temperature so as to provide fine control of SPD characteristics such as switching speed and power consumption.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for producing sorbic acid and its derivatives (e.g., sorbic acid salts, sorbic acid esters, etc.). More particularly, the invention pertains to the use of a novel catalyst in the production of a crotonaldehyde-ketene adduct (an intermediate of sorbic acid to be referred to simply as a polyester) from crotonaldehyde and ketene.
2. Description of the Prior Art
Sorbic acid and its derivatives are characterized by a superior fungicidal activity and non-toxicity to man and are useful as food additives.
One typical method for the commercial production of sorbic acid comprises reacting crotonaldehyde with ketene in the presence of a catalyst and distilling off the unreacted crotonaldehyde or solvent from the reaction product to form a polyester (to be referred to as the synthesizing step), hydrolyzing the polyester in the presence of a mineral acid or an alkali hydroxide or heat-decomposing it in the presence of a catalyst to form crude sorbic acid (to be referred to as the decomposition step), and purifying the crude sorbic acid by distillation, adsorption, crystallization, etc., to form purified sorbic acid (to be referred to as the purification step).
Generally, improvement of a certain method is done by a completely remedial method or a coping method. Certainly, the former is a better measure, and this is true also with the production of sorbic acid. Usually, a method for producing sorbic acid is evaluated by the yield and purity (as shown by the degree of whiteness, etc.) of the resulting sorbic acid. Improvement of these factors is effected by improving the step of synthesizing the polyester, the source of sorbic acid. It is desirable to produce a polyester of better grade (as reflected by purity, etc.) in a higher yield. This is because from the standpoint of the overall process of producing sorbic acid, the purity of the polyester determines the portion of the polyester which is convertible to sorbic acid, and better purities naturally lead to higher yields of sorbic acid. The balance obtained by subtracting the purity of the polyester from 100% is that portion of the polyester which is not convertible to sorbic acid. This portion often becomes tarry at the time of decomposition or hydrolysis of the polyester, and reduces the grade of the resulting sorbic acid. As a result, an increased load is exerted on the subsequent purification step for the production of sorbic acid of a higher grade. This gives rise to an increase in the loss of sorbic acid incident to purification, and consequently reduces the yield of sorbic acid, resulting in a vicious circle. Thus, poor purities of the polyester result in poor yields and grades of sorbic acid.
Conventionally known catalysts used in the addition reaction of crotonaldehyde with ketene in the synthesizing step include, for example, Lewis acids such as boron fluoride and aluminum chloride (see U.S. Pat. No. 2,484,067), zinc salts of organic acids containing not more than 3 carbon atoms (see French Pat. No. 1,309,051), metal salts of fatty acids containing 4 to 18 carbon atoms (see Japanese Patent Publication No. 7212/62), and zinc sorbate (see British Pat. No. 885,217). However, the Lewis acids do not give results which are feasible in practical applications. Testing of the fatty acid metal salts has shown that the yield and purity of the polyester in the synthesizing step are low. Furthermore, in the decomposition and purification steps, the yield and whiteness of sorbic acid are poor, and by-product tarry materials occur in large amounts. In other words, the portion of the polyester which is convertible to sorbic acid, which corresponds to the purity of the polyester, is small. To put it another way, the yield and grade of the resulting sorbic acid are reduced because the portion of the polyester which is not convertible to sorbic acid is large.
SUMMARY OF THE INVENTION
Accordingly, a principal object of the present invention is to provide a process for producing sorbic acid from a better grade adduct of crotonaldehyde and ketene.
A more particular object of the present invention is to provide a process for preparing sorbic acid from an adduct which has a low tarry portion.
A further object of the present invention is to provide a process for producing sorbic acid having low colored matter.
Extensive investigations have led to the discovery that when a phosphine or a pyridine is used in addition to a zinc salt of an aliphatic carboxylic acid as a catalyst in the production of the polyester in the synthesizing step, the grade of the resulting polyester can be improved markedly, and, as a result, the yield and grade of sorbic acid in the subsequent decomposition and purification steps increase remarkably, and moreover, the resulting sorbic acid has a low content of colored matter and thus decreases the load on the subsequent purification step. Thus, the present invention provides a markedly improved process for producing sorbic acid and its derivatives over the conventional processes.
Thus, according to this invention, there is provided a process for producing sorbic acid and its derivatives, which comprises reacting crotonaldehyde with ketene in the presence of a catalyst, and decomposing or hydrolyzing the resulting adduct, said catalyst comprising a zinc salt of an aliphatic carboxylic acid and a phosphine or a pyridine.
DETAILED DESCRIPTION OF THE INVENTION
The zinc salt of aliphatic carboxylic acid used in this invention may be a salt containing water of crystallization or an anhydrous salt. The aliphatic carboxylic acid is a saturated or unsaturated aliphatic carboxylic acid having at least 2 but up to 18 carbon atoms and preferably 2 to 6 carbon atoms. Suitable aliphatic carboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, sorbic acid, stearic acid, etc.
Suitable phosphines are tertiary phosphines of the general formula R 1 R 2 R 3 P, in which each of R 1 , R 2 and R 3 represents an alkyl or aryl group. The alkyl group may be a straight chain, branched chain or cyclic alkyl group having 1 to 8 carbon atoms. The aryl group includes a phenyl group, an alkyl-substituted phenyl group (such as a tolyl group) and a halogen-substituted phenyl group (such as a p-chlorophenyl group). Specific examples of the tertiary phosphines are triethylphosphine, tripropylphosphine, tributylphosphine, triphenylphosphine, dimethylphenylphosphine and methyldiphenylphosphine.
Suitable pyridines are those expressed by the formula ##STR1## wherein each of R 4 , R 5 , R 6 , R 7 and R 8 represents a hydrogen atom or a lower alkyl group (preferably a straight chain or branched chain alkyl group having 1 to 4 carbon atoms). Specific examples of these pyridines are pyridine, picoline, lutidine, gamma-collidine, tetramethylpyridine, pentamethylpyridine, methylethylpyridine, ethylpyridine, propylpyridine, butylpyridine, etc. A mixture of the phosphine and the pyridine cannot be used, but two or more of pyridines or phosphines can be used together.
The zinc salt of an aliphatic carboxylic acid as a catalyst component is added in an amount required to maintain the catalytic activity depending on the reaction temperature or the solubility of the zinc salt in the solvent used. Usually, the amount of the zinc carboxylate is about 0.1 to 5.0% and preferably about 0.2 to 4.0% by weight based on the crotonaldehyde. A suitable amount of the phosphine, the other catalyst component, is about 0.3 to 1.0 mol and preferably about 0.4 to 1.0 mol per mol of the zinc salt of the aliphatic carboxylic acid, and a suitable amount of the pyridine is about 0.5 to 3.0 mols and preferably about 1.0 to 2.5 mols per mol of the zinc salt of the aliphatic carboxylic acid.
The addition of the catalyst does not require a particularly complex operation, and the aliphatic carboxylic acid zinc salt and the phosphine or pyridine may be added successively or simultaneously. Preferably, the reaction is started after the mixture of the added components is stirred for about 30 minutes. Mixing of the aliphatic carboxylic acid zinc salt and the phosphine or pyridine possibly results in the formation of a complex between these components, forming a catalytically active species in the process of this invention. Hence, a separately prepared complex between the aliphatic carboxylic acid zinc salt and the phosphine or pyridine may be used as a catalyst ingredient.
The process of this invention is practiced by contacting liquid crotonaldehyde with gaseous ketene either batchwise or continuously. The ketene can be used at atmospheric pressure or at higher or lower pressures depending upon the mode of generation. It is also possible at this time to dissolve the catalyst in crotonaldehyde as a solvent and react the solution with ketene in a molar proportion less than the crotonaldehyde. Alternatively, in carrying out the reaction the catalyst may be diluted with another solvent such as an aromatic hydrocarbon (e.g., benzene, toluene, xylene, chlorobenzene, nitrobenzene, etc.); an aliphatic hydrocarbon (e.g., n-hexane, heptane, octane, etc.); a chlorinated hydrocarbon (e.g., chloromethylene, chloroform, carbon tetrachloride, etc.); or an alicyclic hydrocarbon (e.g., cyclohexane, cycloheptane, etc.). The reaction temperature should be determined by considering the boiling point of the solvent. Usually, the suitable reaction temperature is from about 0° to 60° C. Removal of the excess of crotonaldehyde or solvent by distillation from the resulting reaction mixture gives the polyester.
When the polyester is heat-decomposed in a customary manner in the presence of an alkali catalyst such as potassium carbonate or sodium acetate, or hydrolyzed in a customary manner with a strong acid such as hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, etc. or a strong alkali such as an alkali hydroxide (e.g., NaOH, KOH, etc.), sorbic acid or sorbic acid salts are formed. When this procedure is performed in the presence of an alcohol, a sorbic acid ester can be directly obtained.
As a specific embodiment of the present invention, hydrolysis of the polyester with hydrochloric acid is shown below.
The suitable weight ratio of the polyester to hydrochloric acid is from 1:1 to 1:3, and the suitable hydrochloric acid concentration in its aqueous solution is at least 30% (i.e., concentrated hydrochloric acid). The hydrolysis temperature is chosen from the range of 50° to 120° C. When the resulting mixture is treated by filter or centrifuge, crude sorbic acid is obtained. To obtain purified sorbic acid, the crude sorbic acid is treated in a known manner such as distillation, adsorption or crystallization.
The process of this invention affords high purity polyester in high yields. Sorbic acid of high grade can be obtained in high yields by decomposing and then purifying the polyester. Since the resulting polyester has a very reduced content of by-product tarry materials as compared with polyesters obtained by the conventional processes, the color of the resulting sorbic acid is markedly improved, and therefore, the subsequent purification step can be performed advantageously.
In the purification step subsequent to decomposition, the reduced content of by-product tarry materials means a marked decrease in the load on conventionally practiced purifying operations such as distillation, adsorption (including ion exchange treatment and activated carbon treatment), recrystallization, and washing. Specifically, in the distillation method, the rectifying effect can be small (i.e., the impurities to be removed are small), the diameter and the number of trays in the distillation tower can be reduced, and moreover, the amount of heat energy consumed decreased. In the adsorption method, the volume of the apparatus can be reduced, and the amount of the adsorbent can also be decreased. In the recrystallization method or the washing method, the amount of the solvent used decreases, and the number of treating cycles can be reduced. Furthermore, the amounts of required subsidiary materials used decrease, and the cost of recovering them also decreases. With the reduced load on these operations the change of sorbic acid to a tarry material with time can also be inhibited. Thus, the industrial value of the process of the invention is very great.
The following Examples and Comparative Examples illustrate the present invention in greater detail. All parts in these Examples are by weight.
EXAMPLE 1
2 parts of zinc isobutyrate was added to 600 parts of crotonaldehyde, and 1 part of tri-n-butyl phosphine was added thereto. The mixture was stirred at room temperature for 30 minutes, and 179 parts of gaseous ketene was introduced into the mixture. During this time, the reaction mixture was maintained at 40° to 50° C. After the reaction, the unreacted crotonaldehyde was distilled off at a reduced pressure of 50 mmHg to afford 473 parts of a clear pale yellow polyester having a high viscosity. The apparent yield of the polyester based on the ketene was 99.1%. The molecular weight of the resulting polyester, measured by a vapor pressure osmometer, was 4,300 on an average.
100 parts of concentrated hydrochloric acid was added to 67.5 parts of the resulting polyester. The mixture was heated to 80° C. to hydrolyze the polyester. After cooling, the product was treated by a centrifugal separator to obtain crude sorbic acid. The crude product had a reduced content of by-product tarry matter. The crude sorbic acid was decolorized with activated carbon, and crystallized from an aqueous solution to afford 57.5 parts of sorbic acid having a melting point of 134° C. The yield of sorbic acid based on the polyester was 85.2%. The apparent purity of the polyester is evaluated by the yield of sorbic acid based on the polyester. To evaluate the whiteness of the resulting sorbic acid, 1 g of the sorbic acid was dissolved in a 1 N sodium hydroxide solution and the total amount was adjusted to 10 ml. The transmittance of this solution was measured at a wavelength of 400 mμ using a 1 cm cell with a 1 N sodium hydroxide solution as a control. The transmittance was 89.0%.
COMPARATIVE EXAMPLE 1
Instead of the zinc isobutyrate and tri-n-butyl phosphine, 2 parts of zinc isobutyrate alone was added to 600 parts of crotonaldehyde. With stirring, 179 parts of gaseous ketene was introduced. During this time, the reaction temperature was maintained at 40° to 50° C. After the reaction, the reaction mixture was worked up in the same way as in Example 1. The apparent yield of the polyester based on the ketene was 89.6%. The polyester had a clear yellow color, and a molecular weight of 2,100. The yield of sorbic acid obtained from the polyester was 76.9%. The transmittance of the sorbic acid solution was 71.0%, and the amount of by-product tarry matter was large.
EXAMPLE 2
Example 1 was repeated using 2 parts of zinc acetate and 1 part of tri-n-butyl phosphine instead of the zinc isobutyrate and tri-n-butylphosphine used in Example 1. The yield of the resulting polyester based on the ketene was 99.6%. The color of the polyester was clear pale yellow. The yield of sorbic acid obtained from the polyester was 84.8%. The transmittance of the sorbic acid solution was 87.5, and the amount of by-product tarry matter was small.
COMPARATIVE EXAMPLE 2
Example 2 was repeated using 2 parts of zinc acetate alone instead of the zinc acetate and tri-n-butylphosphine used in Example 2. The yield of the polyester based on the ketene was 89.1%, and the color of the polyester was brown. The yield of sorbic acid obtained from the polyester was 78.4%. The transmittance of the sorbic acid solution was 74.0%, and the amount of by-product tarry matter was large.
EXAMPLE 3
Example 1 was repeated using 2 parts of zinc isobutyrate and 1 part of triphenylphosphine instead of the zinc isobutyrate and tri-n-butylphosphine used in Example 1. The yield of the polyester based on the ketene was 98.9%, and the yield of sorbic acid obtained from the polyester was 84.2%. The transmittance of the sorbic acid solution was 86.8%.
EXAMPLE 4
Example 1 was repeated using 2 parts of zinc isobutyrate and 1.4 parts of pyridine instead of the zinc isobutyrate and tri-n-butylphosphine used in Example 1. The yield of the polyester based on the ketene was 99.1%, and the yield of sorbic acid obtained from the polyester was 84.0%. The transmittance of the sorbic acid solution was 88.0%.
EXAMPLE 5
Example 1 was repeated using 2 parts of zinc isobutyrate and 1.7 parts of α-picoline instead of the zinc isobutyrate and tri-n-butylphosphine used in Example 1. The yield of the polyester based on the ketene was 99.5%. The yield of sorbic acid obtained from the polyester was 85.5%. The transmittance of the sorbic acid solution was 88.5%.
EXAMPLE 6
Example 1 was repeated using 2 parts of zinc acetate and 1.9 parts of 2,5-lutidine instead of the zinc isobutyrate and tri-n-butylphosphine used in Example 1. The yield of the polyester based on the ketene was 99.8%, and the yield of sorbic acid obtained from the polyester was 86.0%. The transmittance of the sorbic acid solution was 89.5%.
EXAMPLE 7
Example 1 was repeated using 2 parts of zinc acetate and 1.9 parts of 2,4-lutidine instead of the zinc isobutyrate and tri-n-butylphosphine used in Example 1. The yield of the polyester based on the ketene was 99.7%, and the yield of sorbic acid obtained from the polyester was 85.8%. The transmittance of the sorbic acid solution was 88.5%.
EXAMPLE 8
Ethanol (300 parts) and 3 parts of concentrated sulfuric acid as a catalyst were added to 100 parts of the polyester obtained in Example 1, and the mixture was reacted under reflux for 1 hour, followed by distillation at a reduced pressure of 10 mmHg to afford 109 parts of ethyl sorbate. The yield of the ethyl sorbate based on the polyester was 87.5%.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
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A process for producing sorbic acid and its derivatives, which comprises reacting crotonaldehyde with ketene in the presence of a catalyst and decomposing or hydrolyzing the resulting adduct, said catalyst comprising a zinc salt of an aliphatic carboxylic acid and a phosphine or a pyridine.
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[0001] This application for patent claims the benefit of U.S. Provisional Application Ser. No. 61/808,207 entitled CONDOM filed Apr. 3, 2013.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to a condom for contraceptive and prophylactic use, and ultimately, enhanced pleasure. In particular, this invention relates to an improved condom for vaginal intercourse which encourages its use beyond merely for prevention and protection.
[0003] The use of conventional condoms for contraceptive and prophylactic use has been known for years. The present invention is directed to overcoming the negative stigma of traditional condom use by providing an alternative use technique which heightens pleasure beyond natural intercourse. Sexually transmitted diseases are a public health concern that affects all people, regardless of nationality and age group. The medical profession, along with governmental and health organizations, strongly advocate the use of condoms to prevent unplanned pregnancies and the spread of sexually transmitted diseases, including the human immunodeficiency virus (HIV) that can result in acquired immune deficiency syndrome (AIDS).
[0004] The male condom is donned on the penis of the male partner during sexual intercourse. The typical male condom is a snug fitting, elongated tubular sheath emulating the natural contours of the penis. It has an open, proximal end for the insertion of the penis, and a closed, distal end to receive the ejaculate of seminal fluids. Typically, conventional condoms are produced using a dip molding process with glass formers to achieve a wall thinness to maximize tactile sensations through the material. The open, proximal end has a peripheral bead for rigidity to assist donning and doffing, and ultimately, constrictively securing the condom on the penis. The condom material barrier and the agents within the lubricant provide a very substantial shield. These agents include spermicides and microbicides which inactivate or block infection by sexually transmitted pathogens.
[0005] Several condoms have been developed with various irregularities on an otherwise smooth, exterior surface to stimulate the female anatomy for heightened pleasure. They include ridges, blisters, bunched-up excess material, and protrusions. However, the thin flaccid membrane lacks sufficient structural rigidity to retain any effective shape minimizing their effectiveness.
[0006] During intercourse, the female participant only receives tactile stimulation of the vulva and perineum regions at the moment of full penetration by the male. Thus, most of the various textures and projections about the proximal condom opening are relatively non-effective for sustained, female stimulation.
[0007] The difficulties and limitations suggested in the preceding and desired features are not intended to be exhaustive but rather are among many which may tend to reduce the effectiveness and user satisfaction with condoms. Other noteworthy problems and limitations may also exist; however, those presented above should be sufficient to demonstrate that condoms appearing in the past will admit to worthwhile improvement.
BRIEF SUMMARY
[0008] One preferred embodiment of the invention which is intended to address concerns and accomplish at least some of the foregoing objectives comprises a condom capable of being dip molded using glass formers to achieve wall thinness and its unique characteristics. This embodiment possesses a tether extending from the distal region of the condom body of sufficient length to allow a participant to grasp during sexual intercourse. Preferably, the tether is simply an axial or angular extension of the condom body with a diminished diameter, or may be a separate piece attached at or near the distal region of the body. This allows the tether attachment point to stay within the vagina or near the vaginal opening during the male's partial withdrawal to ensure vulva region contact and sustained stimulation, and the positioning of the condom on the penis. The tether can have several different surface configurations, from very aggressive to extremely subtle, for varied levels of stimulation.
DRAWINGS
[0009] Other objects and advantages of the present invention will become apparent from the following detailed description of preferred embodiments thereof taken in conjunction with the accompanying drawings wherein:
[0010] FIG. 1 is an axonometric view of a condom in accordance with one embodiment of the subject invention.
[0011] FIG, 2 is another axonometric view of the same condom
[0012] FIG. 3 is a cross sectional view of FIG. 1 .
[0013] FIG. 4 is an axonometric view of a condom in accordance with the preferred embodiment of the subject invention; the main variation is the tether geometry.
[0014] FIG. 5 is a side view of an alternative with an angled tether.
[0015] FIG. 6 is a cross sectional view of FIG. 5 .
[0016] FIG. 7 is a side view of an alternative embodiment; the main variation is the tether mechanical attachment to the body.
[0017] FIG. 8 is a cross section view of FIG. 7 .
[0018] FIG. 9 is an alternate embodiment of the invention where the extension is provided with transverse ribs or balls.
DETAILED DESCRIPTION
[0019] Referring now particularly to the drawings, wherein like reference characters refer to like parts, and initially to FIG. 1 , there will be seen an axonometric view of the condom 10 in accordance with a preferred embodiment of the invention. The condom 10 in FIG. 1 is to be donned by the male participant about his penis. This condom 10 has a sheath body 11 with a distal end 12 and an open, proximal end 14 . At the distal end 12 , a tether 13 extends axially from the body sheath 11 . The distal end 15 of tether 14 is preferably closed. At the open proximal end 14 , the condom 10 has a beaded cuff 16 formed by back-rolling cuff material. This cuff 16 provides rigidity to assist in donning and doffing the condom 10 , and constrictively securing the condom 10 about the penis. In the distal region 12 of condom 10 , there is an enlarged section 17 designed to entrap the head of the penis when the tether 14 is pulled in an opposing direction to the penis caused by being within the vagina. This region is also for the containment of ejaculated seminal fluids. The juncture 18 of the condom body 11 and tether 14 is a seamless continuation of the wall material. Both the tether 13 and the condom body 11 taper towards their distal ends, 15 and 12 . The axial alignment with draft greatly facilitates stripping the finished condom 11 from the dipping former.
[0020] The axonometric view of condom 10 in FIG. 2 reveals the proximal open end of the sheath 11 banded by the beaded cuff 16 .
[0021] The cross-sectional view of condom 10 in FIG. 3 displays the seamless juncture 18 in the wall structures of the sheath body 11 and tether 13 .
[0022] FIG. 4 shows a condom 30 with a similar sheath structure 31 and a varied textured tether 33 . In this tether 33 has a helical “drill bit” geometry 34 to create sustained, random surfaces from ridges 35 and valleys 36 for stimulation of the vulva region and clitoris of a female partner during thrusting intercourse.
[0023] A side view of condom 40 in FIG. 5 illustrates an angular tether 43 extending at approximately a 45 degree angle with respect to an imaginary central longitudinal axis of the sheath body 41 which is integrally molded onto a distal region 42 of sheath body 41 . Juncture 44 of the tether 43 is a seamless continuation in the wall structure of the sheath 41 and the tether 43 , as revealed in cross-sectional view FIG. 6 . In this embodiment of the subject condom the sheath does not have an enlarged area at the distal region 42 and instead relies on the pliable nature of the thin material 45 for entrapment of the head of the penis when the tether 43 is pulled in an opposing direction to the penis caused by being within the vagina. Seminal fluid is contained within a base region 47 of the integral tether 43 .
[0024] FIG. 7 depicts a condom 50 with a body sheath 51 and a separate tether 53 that is attached, as opposed to being integral, with the body sheath 51 . The condom body sheath 51 and a separate tether 53 are separately dip molded and then physically attached at juncture 54 . The distinct, separate walls of the body sheath 55 and the tether 53 are shown in the cross-sectional view in FIG. 8 . The secure juncture 54 may be constructed thermally or with an adhesive. There is a provisional blister 57 in the distal region 52 of the sheath 51 for containment of seminal fluid.
[0025] FIG. 9 discloses yet another embodiment of the invention where a tether extension 60 may be a flat strip with a series of transversely extending ribs or a plurality in serially connected spheres or balls 62 .
[0026] In use the subject condom is designed to be worn by a male partner with the tether extending in a reverse fold posture along the top of the condom upon insertion during intercourse. A female partner grasps the distal end of the tether and by gentle pulling on the end of the tether is able to control the pressure of the tether structure gliding across the female clitoris as the male partner thrusts in a conventional missionary intercourse position. The condom is composed of any conventional condom composition and the tether is fabricated with the same material as the condom such as for example a latex rubber composition or other materials having elastic characteristics.
[0027] In describing the invention, reference has been made to preferred embodiments and illustrative advantages of the invention. Those skilled in the art, however, and familiar with the instant disclosure of the subject invention may recognize additions, deletions, modifications, substitutions and other changes that will fall within the purview of the subject claims.
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A condom features a generally cylindrical sheath with an open proximal end and a distal end that fits onto a male penis. The condom also features a tether which is connected at the distal end of the sheath. The tether has an axial length greater than the axial length of the sheath and is designed to be grasped by a female partner during intercourse and placed into a rubbing contact the clitoris.
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