Abstract: A pressure transducer for measuring the pressure of a fluid comprising a housing having a cavity. A diaphragm capable of displacement is located within the cavity, dividing the cavity into a first and second chamber. The first chamber is capable of receiving a fluid to be measured, typically a liquid or a gas, while the second chamber contains a liquid such as a silicon oil. The second chamber also contains a gas and means for measuring the displacement of the diaphragm. Upon pressure being exerted against the diaphragm from the fluid, the diaphragm displaces against the liquid and gas, compressing and dissolving the gas as pressure is increased. Displacement of the diaphragm is measured by a measuring device, such as a strain gauge. When the gas is fully dissolved, further movement of the diaphragm is limited by the compressibility of the liquid.

Abstract: An inner space of an outer case is partitioned by a gas permiable diaphragm into a fluid pressure operating chamber and a reference pressure operating chamber. The former chamber communicates with a pressurized fluid inlet hole formed in the case, and the latter communicates with a pressure equalizing hole formed in the case. Electrical contacts are stored in the latter chamber to perform on/off-operation in response to deflection of the diaphragm caused by pressure change of pressurized fluid in the former chamber. Outer connection terminals for the contacts are supported by the outer case. A filter is provided in the equalizing hole.

Abstract: A switch having first and second housing members 12, 14 sandwiching a combination terminal and disc seat member 30 has a tortuous vent path 64, 66 and 68 formed through first and second, annular bearing surfaces 60, 62 in the top surface of the second housing member. The terminal and disc seat member 30 and top surface 42 of the second housing member are configured such that an interference fit is formed between the terminal and the disc seat member 30 and the second, annular bearing surface 62.

Abstract: A field emission device with an emitter on a first layer of material and an anode on a second layer of material, separated by a predetermined distance, with a sealed region therebetween. Changes in pressure external to the sealed region producing movement and consequent changes in the predetermined distance between the first and second layers, which change in distance produces a change in current between the emitter and anode. The change in current representing the change in differential pressure.

Abstract: A pressure sensitive control device having a housing made up of a plurality of housing members, a diaphragm, a bistable snap-disc, a switch and an actuator. The snap-disc moves from one configuration to another upon application of pressure over a predetermined amount to drive the actuator which moves the switch from its normal operating position, which can be either closed or open, to a tripped position, which is opposite its normal operating position. Two adjacent housing members, which support the snap-disc and switch, respectively, are formed with cooperating spacers which allow the spacing of these housing members to be continuously varied over a small range of adjustment to allow the switch point of the control device to be adjusted after partial assembly of the control device. The diaphragm and some of the housing members may be subassembled for testing the components of the control device prior to complete assembly.

Abstract: A variable reluctance transducer system incorporating digital control of parallel resonant circuits including two inductive sensors L1 and L2 on each side of a flat diaphram. The dual variable reluctance elements provide dual frequency signals for digital calculation to obtain a quotient of the frequencies, thereby substantially eliminating the resonant frequencies as a variable in the accuracy of the device. Manipulation of the produced quotient by a micro-controller 10 employing digital calibration tables stored in a programmable read only memory 14 allows calibration reponsive to a temperature sensor 16, thereby substantially eliminating temperature induced errors in the system, further increasing accuracy.

Abstract: A pressure/control gage (12) includes a housing (4) defining an elongate, generally funnel shaped fluid chamber (6) having an open end (8) at the base of the fluid chamber. The open end is sealed by a diaphragm (10). The sealed fluid chamber includes a liquid (26), such as mercury, and a gas (28) defining an interface (30) between the two. The liquid is positioned against the inner surface (20) of the diaphragm. The outer surface (22) of the diaphragm is coupled to a source of pressure (18). The location of the interface changes according to the pressure applied to the outer surface of the diaphragm. Preferably the housing is clear, so the interface can be visually observed, with visual markings (32, 34) indicating the pressure. Also disclosed is a novel surge control valve (40) in which a resilient material (42) is positioned transversely across the fluid passageway (24) connecting the pressure source and the diaphragm.

Abstract: An improved pressure sensor element and pressure sensor array is formed by a cathode layer, a cathode tip attached to the cathode layer, and an anode layer opposing the cathode layer. The magnitude of the electron current flowing between the cathode tip and the anode layer is dependant on the field strength at the cathode tip, which is dependant on the separation between the cathode tip and the anode layer. As a deflectable anode layer is deflected towards the cathode tip, the field strength increases, causing a corresponding change in the magnitude of the flow of electrons. The cathode tip is separated from the anode layer such that electron current is produced at relatively low voltages by tunneling or field emission. The exact method of current production is selected by controlling the initial separation between the anode layer and the cathode tip.

Abstract: A microsensor or micromechanical device based upon the piezoelectric properties of thin film lead zirconate titanate (PZT) with a thickness of between 0.1 and 5 microns. The thin film PZT is sandwiched between first and second electrodes which are provided with electrical connection means for electrically connecting the electrodes to a voltage sensor or voltage source. The invention also relates to a method for making such microsensor or micromechanical device.

Abstract: A pressure sensitive control device having a housing made up of a plurality of housing members, a diaphragm, a bistable snap-disc, a switch and an actuator. The snap-disc moves from one configuration to another upon application of pressure over a predetermined amount to drive the actuator which moves the switch from its normal operating position, which can be either closed or open, to a tripped position, which is opposite its normal operating position. Two adjacent housing members, which support the snap-disc and switch, respectively, are formed with cooperating spacers which allow the spacing of these housing members to be continuously varied over a small range of adjustment to allow the switch point of the control device to be adjusted after partial assembly of the control device. The diaphragm and some of the housing members may be subassembled for testing the components of the control device prior to complete assembly.

Abstract: An improved pressure sensor element and pressure sensor array is formed by a cathode layer, a cathode tip attached to the cathode layer, and an anode layer opposing the cathode layer. The magnitude of the electron current flowing between the cathode tip and the anode layer is dependant on the field strength at the cathode tip, which is dependant on the separation between the cathode tip and the anode layer. As a deflectable anode layer is deflected towards the cathode tip, the field strength increases, causing a corresponding change in the magnitude of the flow of electrons. The cathode tip is separated from the anode layer such that electron current is produced at relatively low voltages by tunneling or field emission. The exact method of current production is selected by controlling the initial separation between the anode layer and the cathode tip.

Abstract: A piezoelectric pressure sensor is provided with a sensor housing including an inner sensor housing, accommodating an piezoelectric element, and an outer sensor housing threaded to a test article. The inner sensor housing is attached to the outer sensor housing in such a manner that a prestress applied to the piezoelectric element does not change due to an axial strain in the outer sensor housing. The axial strain is produced when the outer sensor housing is mounted to a test article.

Abstract: Members as an upper fixing screw, a piezoelectric element, a pressure transmitting member are located closer to region of an engine to be measured and the like than a fitting thread portion of a sensor casing so that a pre-stress on the piezoelectric element can be constantly maintained at a predetermined value, thus enabling pressure measurement with a high degree of accuracy. Further, a projecting portion or a spacer is provided on the backside of a pressure receiving surface in order to ensure the surface contact between the pressure transmitting member and the back surface of the pressure receiving surface, thus preventing the stress from concentrating on corners of the bottom surface of the pressure transmitting member.

Abstract: A residual ink quantity detecting apparatus for detecting a residual quantity of ink in a supply source of ink for supplying ink to an ink-jet printer comprises a deviation member, which is connected to an ink supply path extending from the supply source, constitutes part of the path and can be deviated upon change in pressure in the path, an adjusting member for adjusting a deviation of the deviation member in order to set a pressure at which the deviation member is deviated and a detection unit for detecting the deviation of said deviation member.

Abstract: A differential pressure switch has a main switch body divided into three chambers by means of two diaphragms, thereby sealing the center chamber that contains a snap-action switch. The two diaphragms are mechanically connected by a strut that can move only along a single line of motion, so that movement of one diaphragm is transmitted to the other. Movement of the strut is coupled to an actuator of the snap action to produce the desired switching action.

Abstract: An optical pressure transducer employing input and output optical fibers defining therebetween an optical path. The optical path is interrupted by a fixed reflector and a moveable reflector. The moveable reflector is secured by adjustment means to the diaphragm that is responsive to pressure being measured.

Abstract: A pressure switch according to the invention combines a pressure chamber with diaphragm, plunger, spring-loaded switch mechanism and electrical contacts in a single compact assembly. According to one aspect of the invention, the terminal board of the pump motor is incorporated into the control switch housing, eliminating the need for wiring from the switch to the terminal board and enabling the switch to be mounted inside the wiring compartment of the motor. According to another aspect of the invention, a pair of opposing blades are used in the switch mechanism to eliminate side forces and decrease friction, improving accuracy and life of the switch. A simple set screw may be used with one of the switch blades, in cooperation with a stop associated with the other blade, to adjust the spring force and thereby control the pressure control differential.

Abstract: An orthopedic exercise chamber such as a slipper including a light-weight, self-contained limb load monitor is disclosed. The limb load sensor circuit provides extended service life for the miniature power supply that is included in the slipper, thereby making the slipper suitable for out-patient use. A fluid-filled plantar chamber that supports the entire load borne by the patient's foot is connected to the sensor circuit, thereby providing improved monitoring of the load being carried by the leg or foot that must be protected from excessive loading.

Abstract: In a pressure transducer (11), the diaphragm (14) is fastened at the front side of the housing (10) facing the combustion chamber of an internal combustion engine by weld connections. The pressure acting on the diaphragm (14) is transmitted via the plunger (16) to a sensor block (18) including a plurality of piezoelectrically acting crystals (19, 20). The quartz disks (19, 20) are glued together with one another and with an intermediate electrode (21) as well as with the housing (10) of the pressure transducer (11) by a conducting glue. The plunger (14), the abutment (23) and the piezoelectrically acting crystals (19, 20) are connected in the housing (10) so that force transmission to the crystals (19, 20) occurs without mechanical pretensioning. The pressure transducer (11) is virtually free of dynamic temperature errors and enables a relatively exact determination of the pressure curve with respect to time in the combustion chamber of an internal combustion engine in long-term operation.

Abstract: The pressure sensor consists of a substrate and a diaphragm joined together around the periphery so as to form a chamber. The surface of the diaphragm facing away from the substrate is exposed to a medium whose pressure is to be measured. To protect the diaphragm against corrosion or abrasion, the diaphragm surface exposed to the medium is covered with a layer of silicon carbide, preferably by chemical vapor deposition.

Abstract: A differential pressure switch assembly for low pressure applications permitting accurate "in field" set pointing of same, comprising a capsulized instrument that includes housing high and low pressure sections defining in assembled relation a pressure cavity across which such sections mount a flexible diaphragm separating high and low pressure chambers, with the low pressure section mounting at a site on the low pressure section a snap switch unit of a size appropriate for such assembly, which unit has a projecting plunger therefor that has an end portion disposed in the low pressure chamber of the unit, with the assembly further comprising a pressure differential sensor disposed for effecting electrical switching of the snap switch unit when the pressure of the assembly high pressure chamber exceeds that of the low pressure chamber by a predetermined differential.

Abstract: A condition responsive sending and indicating unit for sensing a condition and transmitting a signal representative of the sensed condition to an indicator at a remote location. The sending unit includes indicia for giving an indication of the sensed condition at the site of the unit, and has a movable contact operatively associated with a variable resistor in circuit with the remote indicator, whereby a variable signal is produced in response to variation in the sensed condition. Calibration of the unit is accomplished by adjustment of the set point of the movable means, and by adjustment of the position of the resistor relative to the movable contact.

Abstract: A tire pressure sensor for monitoring pressure in the tire of a motor vehicle wheel and comprising a reference pressure chamber, two contact members extending through a bushing insulator arranged in the base of the reference pressure chamber, and an electrically conducting diaphragm that separates the reference pressure chamber from the tire interior. The diaphragm has two contact zones that engage sequentially the two contact members upon being bent in response to air pressure in the tire interior reaching, respectively, a first value and a second value greater than the first value.

Abstract: A pneumatic switch unit includes a switch housing. A conductive contact spring is mounted between diametric supports, one being adjustable. The spring has a central actuator arm and an offset contact arm interconnected to an encircling frame. A two piece switch actuator has clamp members clamped to the actuator arm. Separate end closure members secured to the switch housing ends. The closure member may clamp a diaphragm against the housing, with the diaphragm engaging the actuator. The closure member may have a mechanical actuating member or a simple closure plate engaging the actuator. The two switch housings may be mounted to the opposite sides of a single pressure chamber with end diaphragms closing the opposed ends of the switch housing. The pressure actuates both switch units to establish a sequence switch unit. The spring has a rectangular frame with a central opening having an actuating arm therein. The opposite spring ends are mounted in supports one of which is adjustable.

Abstract: A solid state measurand sensor is described in which the pressure sensor element is protected from the measurand by a combination of a pressure transfer medium and a thin covering membrane. A method is described for forming the diaphragm in situ. The diaphragm material is selected from a group of materials which includes fluorosilicone, so as to substantially avoid entrapment of air or formation of voids in the pressure transfer medium such as would degrade the performance of the sensor. The pressure transfer medium is gel-like material such as dimethyl silicone and equivalents. Alternatively, the gel may be fluorosilicone and the diaphragm may be dimethyl silicone. The membrane material is chosen to be substantially impermeable to the ambients or process media being measured and also flexible, is to be poured and cured in place on the assembly during fabrication.

Abstract: In order to prevent tilting and torsional stresses from entering the actual sensor element of a pressure sensor comprising a supporting part and an integrated sensor part, the proposal is put forward that the coresponding surfaces of a shoulder of the supporting part and of a fastening element screwed into the measuring bore be confugured as the lateral surfaces of cones whose generating lines intersect with the longitudinal axis of the supporting part, or as parts of the surface of a sphere whose center is situated on the longitudinal axis of the sensor part. The two corresponding faces transmitting the pressure from the fastening element onto the supporting part, and permitting a slight tilt of the longitudinal axis of the supporting part relative to the axis of the internal thread of the measuring bore.

Abstract: A transmitter that provides an output indicating pressure difference between a line pressure and atmosphere outside the transmitter is made intrinsically safe by coupling the sensor cavity as well as other cavities where ignition can occur to atmosphere only through flame quenching paths. The opening in the transmitter housing in which the sensor is mounted has a plug including a sensor cavity that holds the sensor, and a fitting which is couplable to the pressure line. An isolator is used for transmitting the process pressure to the sensor through an isolator diaphragm acting on an incompressible filling the sensor cavity and transmitting pressure through a hole that is shaped to provide a flame quenching path. The passageway flame isolates the sensor from the process fluid line. The opposite side of the sensor is connected to atmosphere only through paths which are flame quenching because of the passageway shape.

Abstract: The present invention provides a modular system for mounting one or more medical devices on an IV pole at a patient's bedside. The system comprises a support plate, and at least one modular interconnection receptacle adapted to be detachably mounted on the support plate and adapted to receive a medical device. In one embodiment, the interconnection receptacle has electrical connection means serving as an electrical conduit between the medical device and a monitor. The means for attaching the medical device to the interconnection receptacle has a greater retention force than the means for attaching the interconnection receptacle to the support plate. Thus, in response to a threshold force on the patient line connected to the medical device, the interconnection receptacle breaks free of the support plate while the medical device remains attached to the interconnection receptacle.

Abstract: A manometer device comprising a pointer to be fixed on a scale, a screw to be used to fix the pointer, and a sliding carriage cooperates with the screw; a pair of contacts are bolted on the lower surface of the sliding carriage. The two contacts can be used to connected with a fluid driver, and there is a pressure induction mechanism under the contacts which has a needle to thrust the contact point. With this mechanism, the center of the pressure induction mechanism would thrust the contact point open to cut off the current in the circuit while the pressure in the space to be measured reaches the pressure demonstrated by the pointer, and then the fluid driver would stop to act.

Abstract: A control device, switch unit therefor and methods of making the same are provided, the electrical switch unit comprising a switch having a movable actuator, a lever pivotally carried by the switch unit and having one end adapted to be operatively interconnected to a movable part of a control device so as to be pivoted by the movement thereof, the lever being operatively interconnected to the actuator to operate the switch between the different conditions thereof in relation to the pivoted position of the lever, and a pair of mounting plates respectively having holding structure that hold the switch between the plates and respectively having pivot structure that pivotally mount the lever between the plates whereby the plates, the switch and the lever form a self-supporting switch unit.

Abstract: In a transducer, e.g. a pressure transducer, the sensing element comprises a torsional oscillator provided with magnetic means for feedback of signals to maintain oscillation. Typically the sensing element is formed by selective etching from a body of single crystal silicon.

Abstract: A control device, switch unit therefor and methods of making the same are provided, the electrical switch unit comprising a switch having a movable actuator, a lever pivotally carried by the switch unit and having one end adapted to be operatively interconnected to a movable part of a control device so as to be pivoted by the movement thereof, the lever being operatively interconnected to the actuator to operate the switch between the different conditions thereof in relation to the pivoted position of the lever, and a pair of mounting plates respectively having holding structure that hold the switch between the plates and respectively having pivot structure that pivotally mount the lever between the plates whereby the plates, the switch and the lever form a self-supporting switch unit.

Abstract: A multicontact vacuum responsive switch includes a housing divided into first and second chambers by a diaphragm. The first chamber is connected to a vacuum source while the second chamber communicates with atmospheric pressure, so that the diaphragm is movable within the housing in response to a pressure differential between the first and second chambers. A plate is connected to the diaphragm for movement therewith, and has an electrically conductive portion of a predetermined pattern. A plurality of electrical contacts are mounted in the housing and slidably contact the plate such that the contacts may selectively contact the electrically conductive portion of the plate in response to movement of the diaphragm means, which also cause movement of the plate. One of the contacts always contacts the conductive portion, and so is a reference contact.

Abstract: A pressure transducer capable of measuring very high pressures with great accuracy. The transducer includes a metal structure enclosing a volume which forms a resonant cavity to provide the tuning element in a UHF oscillator. The resonant cavity provides an inductance and a variable capacitance, the capacitance being variable as a function of the pressure to be measured. A transistor oscillator is very loosely coupled to the tuned circuit and provides positive feedback to maintain the oscillation. Due to the loose coupling between the transistor and the tune circuit, changes in the input reactance of the oscillator circuit have very little affect on the frequency of the tuned circuit. The frequency varies as a function of the pressure and provides an indication thereof. Two embodiments of the transducer are described. A first embodiment includes two concentric tubes, a section at the center of the outer tube being reduced in diameter to form an annular gap to provide the variable capacitance.

Abstract: Disconnection of a fluid conduit from a fluid fitting 38 and electrical conduit from apertures 28 in a fluid pressure sensing switch when servicing is required is avoided in a construction wherein a switch module 12 is secured to a base 10 mounting a fluid pressure receiving fitting 38 and electrical conduit receiving apertures 28 by only two threaded fasteners 24, allowing the module 12 to be separated readily from the base 10 without disturbing conduit connections.

Abstract: A multi-stage pressure-to-electric switch assembly includes a top casing provided with a pressure receiving chamber, a bottom casing integrally secured to the top casing in closing relation to the pressure receiving chamber, and a diaphragm clamped between the top casing and the bottom casing to be in sealing, closing relation to the pressure receiving chamber. This diaphragm is provided with three spaced-apart pressure response switch control portions, each portion including a switch control button. Three two-position electrical switches are fixedly supported with respect to the bottom casing. Three hollow, externally threaded switch control sleeves are aligned between the diaphragm control buttons and the switches. A switch operating control nut is threadably mounted on each of the switch control sleeves, and a switch operating plunger extends through each control sleeve between the diaphragm button and a switch.

Abstract: A pressure receiving member which has a diaphragm held in a pressure receiving case is manufactured independently of a main sensor body member, which has a switch accommodated in a switch case. The pressure receiving member and the main sensor body member are then assembled to provide a pressure sensor.According to the present invention, since the pressure receiving portion and the main sensor body are manufactured individually, a diaphragm inversion movement test can be carried out individually of the testing of switch turning on and off, and hence only satisfactory pressure receiving portion and main sensor body which passed the respective tests will be utilized in the operation of assembling pressure sensors.

Abstract: A strain or pressure responsive transducer comprises a pair of elongate beam resonators arranged end to end and provided with a flexible coupling therebetween. The arrangement oscillates e.g. in a double see-saw or butterfly mode. The transducer is disposed on a diaphragm whereby strain may be transmitted to the oscillatory system. The frequency of oscillation is a function of this strain.

Abstract: A semiconductor integrated pressure transducer in which a semiconductor substrate incorporates a hermetically sealed system comprising a first chamber communicating with a second chamber via a capillary. The first chamber contains a fluid and has at least one portion of a wall in the form of a deformable membrane separating the atmosphere within the chamber from that external to the sensor. The second chamber contains a compressible gas and has rigid walls. The capillary is partially filled with electrically conducting liquid, and the liquid physically separates the fluid in the first chamber from the gas in the second chamber. The wall of the capillary is electrically conductive at least in two separated regions such that in use, at a predetermined external atmosphere pressure, the electrically conductive liquid makes contact with both electrically conductive regions thereby completing an electrical circuit.

Abstract: A tire pressure gauge located within a self-contained enclosure having a changeable numeric display at its exterior. An air inlet on the enclosure is utilized to establish pneumatic communication between the interior of an inflated tire and the interior of the enclosure. The enclosure interior is provided with electronic pressure responsive circuits operably connected to the display for presenting a numerical reading of air pressure. A power control circuit is operated by a programmed CPU, which electronically shifts it between operative and inoperative states to prolong battery life. The programmed CPU also detects maximum pressure readings, which are announced to the user by an electronically driven audible signal device within the hand-held enclosure.

Abstract: A transducer, particularly for ballistic high pressure measurements, comprises an assembly body, with a shoulder sealing section and a sensor member, which can be received in a recess in the assembly body. The assembly body can be screwed into a component, e.g. a gun barrel, the measurement area on the sealing section being sealed. The assembly body has a tubular extension extending beyond the sealing section, which extension encompasses the sensor member on a cylindrical fitting face. The high sealing forces required for sealing the measurement area are kept remote from the sensor member. The measuring sensitivity of the transducer is therefore independent of the prevailing tightening torques. A cylindrical gap between the sensor member and assembly body provides additional insulation between the sealing forces and the prestress forces prevailing in the sensor member. The cylindrical gap is sealed against the pressure medium by a force fit or weld between the assembly body and the sensor member.

Abstract: A fluid pressure transducer apparatus comprising a fluid pressure transducer mechanism and a fluid pressure-transmitting path. The fluid pressure transducer mechanism includes a fluid pressure detection mechanism, having a detection surface of a fluid pressure, for converting a fluid pressure into an electrical signal, and a chamber, formed on the detection surface, for storing a fluid. The path includes a cylindrical member having a first port communicating with the chamber and a plurality of second ports arranged on a surface perpendicular to an axis of the cylindrical member, and a stop cock arranged in the cylindrical member to be slidable with an inner surface of the cylindrical member. The stop cock has a path defined therein and a handle for slidably rotating the stop cock in the cylindrical member through a predetermined angle so that the path communicates the first port with only one of the plurality of second ports and no other second ports communicate with each other.

Abstract: A fluid filled force or pressure sensor for measuring an external force such as a fluid pressure. The apparatus includes a housing having a substantially planar backup surface, a flexible diaphragm having its radially outer portion sealed to the backup surface of the housing. A variable volume fluid chamber is formed between the backup surface and the diaphragm and is filled with a pressurized working fluid causing the diaphragm to flex outwardly away from the backup surface. The apparatus also includes a sensor chamber formed in the housing and in fluid communication with the variable volume fluid chamber. Mounted within the sensor chamber is a means for sensing variations in the density of the working fluid within the sensor chamber, such variations in density being caused by flexing of the diaphragm as a result of variations in the external pressure to be measured.

Abstract: A solid state semiconductor pressure sensor is described in which the pressure sensor element is protected from the ambient whose pressure is being measured by a combination of a pressure transfer medium and a thin covering membrane. A method is described for applying the thin covering membrane so as to substantially avoid entrapment of air or formation of voids in the pressure transfer medium which would degrade the performance of the sensor. The pressure transfer medium is a gel-like material such as a silastic. The membrane is chosen to be substantially impermeable to the ambients being measured and sufficiently flexible to be rolled across the surface of the assembly during fabrication and to avoid attenuation of the input pressure signal. Fluorosilicone is an example of a suitable membrane material.

Abstract: A pressure sensor comprising an air-tight container, enclosing water vapor therein, which elastically deforms depending upon a variation in the external pressure to result in a variation in the content volume thereof, a moisture sensor disposed within the container, and a moisture detector which electrically detects a variation in the amount of moisture to be absorbed by the moisture sensor depending upon the internal partial pressure of the water in the container due to the elastic deformation of the container.

Abstract: A pressure measuring apparatus comprising a diaphragm to which pressure to be measured is applied and a resilient vibrator connected to the diaphragm, which acts to produce a signal based on its natural frequency relative to the pressure, wherein the diaphragm comprises a peripheral circumferential portion, a central fixing portion and a non-planar intermediate portion therebetween, with the central portion being connected to the vibrator and having its edge disposed at a non-perpendicular angle with respect to the vibrator area to which it is connected. The apparatus eliminates adverse influences due to initial distortion, hysteresis of the diaphragm and produces accurate measurements.

Abstract: Aircraft instrument for indicating air pressure, air pressure rate of change and accelerations of the aircraft movement based on the use of an optical laser interferometer. The air pressure is connected to one of several mirrors in the interferometer which causes the interference pattern to move up or down in response to the change in air pressure or acceleration. The interferometer uses a laser beam projected onto an optical detector that senses the motion of the interference pattern and produces a corresponding electrical signal which is connected to a linear motor which in turn is linked to the same mirror but in a negative feed-back arrangement that seeks to restore the position of the interference pattern. The amplifier output is an electrical analog of the atmospheric air pressure. The rate-of-climb is obtained by differentiating the amplifier output. The acceleration is produced by connecting the mirror to a mass.

Abstract: A one piece housing suitable for housing semiconductor chips is molded from a polymer material. Electrical leads pass through a molded one piece housing to provide electrical contact between the semiconductor die and external circuitry. A hole can be provided in the bottom of the package if the package is to be used as a unibody pressure transducer package.

Abstract: Fluid density measuring apparatus and method for directly measuring fluid density or indirectly measuring pressure. The apparatus includes a bellows and a generally rigid hollow housing having openings through which fluid may flow to the interior of the housing, and a vibratory single-ended tuning fork mounted in the housing. The apparatus also includes circuitry for causing the tines of the tuning fork to resonate, for example, 180 degrees out of phase in a transverse direction, with the frequency of the tines varying with variation in the density of the fluid surrounding the tines. Circuitry is also included for determining the frequency at which the tuning fork tines resonate. When the density of the fluid into which the housing is placed changes, the frequency of vibration of the tines of the tuning fork is caused to change to provide a measure of the pressure.

Abstract: In order to prevent tilting and torsional stresses from entering the actual sensor element of a pressure sensor comprising a supporting part and an integrated sensor part, the proposal is put forward that the corresponding surfaces of a shoulder of the supporting part and of a fastening element screwed into the measuring bore be configured as the lateral surfaces of cones whose generating lines intersect with the longitudinal axis of the supporting part, or as parts of the surface of a sphere whose center is situated on the longitudinal axis of the sensor part. The two corresponding faces transmitting the pressure from the fastening element onto the supporting part, and permitting a slight tilt of the longitudinal axis of the supporting part relative to the axis of the internal thread of the measuring bore.