Abstract: A transducer assembly for measuring the pressure difference between first and second pressures comprises a differential pressure transducer and a valve coupled to the differential pressure transducer. The differential pressure transducer has a first pressure region and a second pressure region and generates an electrical signal in response to a pressure differential between the first and second pressure regions. The valve is arranged to connect the first and second pressure regions when the pressure differential exceeds a first value. One embodiment of the valve comprises a chamber and a poppet. The chamber has a first port, a second port, and a wall. The cross sectional flow area of the chamber is larger than the cross sectional flow area of the first or second port.

Abstract: A gage connected to the rod end of the wing cylinder on a multi-section implement senses rod end pressure at the output of the hydraulic wing control (HWC) valve. The HWC valve is engaged or disengaged using the selective control valve (SCV) in the tractor, and the gage provides a visual indication to the operator of the following modes: 1) off; 2) fold wings; 3) unfold wings; 4) field operation--push wings down; and 5) field operation--pull wings up. In field operation, the gage also provides an indication of the force with which the cylinders are pushing or pulling on the wings to affect the cutting force of the wings.

Abstract: A conventional pressure transducer is provided on an adaptive connector wh fits either of two "wet side" bulkhead fittings on the breech door of a torpedo tube. The transducer is electrically connected to a recording device in the submarine by means of a cable with an adaptive connector that is configured to be received on either of the two "dry side" bulkhead fittings.

Abstract: A regulator for pneumatic system comprising a connecting bracket for connecting other air conditioning units to a regulator body. Because of this connecting bracket, the air conditioning units to be connected to each other can be modularized. The connecting bracket has, at its both ends, a pair of projection-like pawl sections which are engageable respectively with engaging sections formed respectively on outer peripheral surfaces of the other air conditioning units. Incorporated in the connecting bracket is a pressure gage for detecting secondary pneumatic pressure within the regulator body. The pressure gage comprises a pressure detecting section, a pressure display section, pressure setting section and an abnormality alarm section.

Abstract: A miniature electronic pressure gauge is described comprising a case (10) having an aperture leading to a transducer (1) connected to an amplifier (3), the transducer (1) and amplifier (3) being powered from a power source (2) in the form of a storage battery such as a Nicod battery. A pressure signal from the amplifier (3) is fed to a linearization circuit (4) and to an analogue/digital converter (6) clocked with pulses from clock generator (5). The output of converter (6) is fed to a decoder/driver (7) for a seven segment L.C.D. (8). In a preferred construction the pressure gauge is releasably retained in a fluid-tight engagement in a bore in the wall of a pressure chamber of a paint spray gun.

Abstract: The present invention provides an improved pressurization device for use with angioplasty balloon catheters, or the like. The device has a novel quick release mechanism which enables rapid advancement of a threaded screw plunger to attain initial pressurization, and then the subsequent engagement of said mechanism with the threaded surface of the plunger to achieve precise control during final pressurization of the balloon catheter. In addition, there is provided an improved and novel pressure indicating means for providing the physician with an analog readout of the pressure being applied to the balloon catheter.

Abstract: An air terminal flow detection scheme in an air distribution system effective for developing static pressure indications of the plenum of the air terminal from change in the flow through the air terminal over the period of time of the change.

Abstract: Apparatus for gauging high pressure gas in particular for the supply of oxygen gas on board on aircraft, the apparatus being associated with a gas tank or with a plurality of gas tanks having their outlets interconnected, the apparatus being wherein each individual tank is provided both with a pressure regulator connected to a common outlet duct, and with a pressure sensor producing a signal proportional to the pressure in the, or each, tank, with the or each, pressure sensor being connected to a calculation and storage unit suitable for determining the content of each individual tank on the basis of the signal associated therewith and taking account of the coefficient of compressibility of the gas contained in each individual tank on the basis of data stored in the storage unit for different values of pressure, and consequently deducing the overall available content, the calculation unit further including a readout for displaying the overall available content.

Abstract: A tire monitoring and repairing device comprises a body having a front arm and a rear grip arm interconnected at their upper end with a connecting member to substantially form a U-shape. A pressure gauge is mounted in the front arm and a flash light device is mounted in the rear grip arm. The front arm further has a mouth piece projecting forward to form a pressure inlet. A tire repairing tool is detachably screwed to the mouth piece of the front arm. In addition, a tire tread ruler is provided in the rear grip arm.

Abstract: A liquid container hydrostatic level gauge, in particular a fuel tank level indicator, which operates with a differential pressure sensor, a zero point calibration related to the height of the fuel is performed upon the beginning of measurement, in order to dispense with a requirement for temperature independence and long-term stability of the zero point of the differential pressure sensor. A meter tube is disposed in the container interior, extending from above the maximum liquid level to as far as the container bottom with an opening for receiving fuel within the tank. The differential pressure sensor is connected by one meter input to the upper end of the meter tube and by its other meter input is exposed to the air pressure acting upon the surface of the liquid. An air pump is connected to the upper end of the meter tube between the upper level of the fuel and the input to the pressure sensor. At the beginning of measurement, the meter tube is flooded, and an output value (U.sub.

Abstract: An air pressure measuring pen of a neat and satisfactory design is provided. The pen includes a transparent hollow pen tube having a top end and a bottom end, a clipping cover connected to the top end and having an exhaust valve, a check valve and a measuring head, a spring urging in the pen tube apart a stopping medium and a piston in the pen tube, an ink holder, and an ink holder positioner connected to the bottom end.

Abstract: A capactive pressure sensor suitable for making highly sensitive, low pressure measurements is disclosed. The sensor may be mounted into a 0.5 mm OD catheter suitable for multipoint pressure measurements from within the coronary artery of the heart. The sensor employs a transducer which consists of a rectangular bulk silicon micro-diaphragm several hundred microns on a side by two microns thick, surrounded by a supporting bulk silicon rim about 12 microns thick. Both the diaphragm and the rim are defined by a double diffusion etch-stop technique. The transducer fabrication process features a batch wafer-to-glass electrostatic seal followed by a silicon etch, which eliminates handling of individual small diaphragm structures until die separation and final packaging. An addressable read-out interface circuit may be used with the sensor to provide a high-level output signal, and allows the sensor to be compatible for use on a multisite catheter having only two electrical leads.

Abstract: A system for measuring level of liquid material in a containment vessel that includes a hollow conduit composed of a first conduit section having an upper end coupled to a pressure sensor and a lower end disposed within the vessel. A second conduit section is coupled to the lower end of the first conduit section and extends downwardly therefrom at least to a minimum material measurement level within the vessel. The second conduit section has a vertical height coordinated with the maximum desired material measurement level within the vessel such that pressure of air captured within the first conduit section at such maximum material level prevents entry of the liquid material into the first conduit section. The cross sectional area of air flow within the second conduit section is at least ten times, and preferably at least sixteen times, greater than the cross sectional area to air flow within the first conduit section.

Abstract: A method for fluid pressure testing of a formation behind casing is set forth. A formation testing tool is lowered into the well to a specified depth opposite a formation of interest behind a casing. A test probe is extended and a perforation is formed from the test probe into the formation to obtain fluid communication with the formation. Utilizing a storage container in the testing tool, fluid is pumped from the formation into the test tool, or from the test tool into the formation and formation pressures are measured at selected intervals.

Abstract: System and method for monitoring gas pressure in semiconductor processing equipment and the like. A small backflow of an inert gas is passed through the monitoring system to isolate the system from corrosive gases in a chamber to which the system is connected. The backflow passes through a flow restrictor of known resistance between a pressure sensor and the chamber, and the drop in pressure across the restrictor is determined and combined with the pressure measured by the sensor to determine the pressure in the chamber.

Abstract: A gauge is described for measuring the gas pressure in high pressure gas cylinders. The gauge is mounted in the high pressure port of the cylinder valve, while gas is delivered through a lower pressure portion. The gauge comprises a cylindrical housing and a retaining nut, with the housing rotatable relative to the retaining nut. The cylindrical housing encloses a coiled bourdon tube which communicates with the gas in the cylinder and coils up or uncoils in response to changes in pressure. A viewing glass encloses a pointer and scale arrangement seated in the housing to permit the gas cylinder pressure to be displayed.

Abstract: Methods, materials and devices for the remote measurement of physical variables with fiber optic systems use a single excitation light source for generating through the use of at least one luminescence converter, both a signal beam and a reference beam, and allow the transmission of both beams through a single fiber to a single photodetector, thus producing photo-electric signals the relative intensities of which are only minimally affected by changes of the intensity of the interrogating light beam, optical losses, or detector drift. In contrast to the prior art, the luminescent materials of this invention can be used either as transducers for physical parameters or as means for processing information from other optical transducers, without requiring a change in the luminescence properties of said materials under the influence of the measured parameter.

Abstract: Multi-functional sensor comprises a support base made from borosilicate, a diaphragm with a E-shaped section secured to the base, the diaphragm being made from single crystalline silicon, principal plane thereof being oriented to be a crystalline plane (110), a differential pressure sensor having p-doped piezoresistor elements formed in the principal plane of the diaphragm at a thin wall portion of the E-shaped sectional diaphragm, each element being arranged along a crystal axis <111>, a static pressure sensor having p-doped piezoresistor elements formed in the principal plane at an outer peripheral thick wall portion of the E-shaped sectional diaphragm, each element being arranged along the crystal axis <111>, and a temperature sensor having a p-doped piezoresistor element formed in the principal plane at the outer peripheral thick wall portion of the E-shaped sectional diaphragm, the element being arranged along the crystal axis <100>.

Abstract: A combination air flow and vacuum meter comprising a rigid transparent tubular housing having an inlet end, an opposite outlet end adapted for insertion into a central vacuum inlet or the like, a compression spring-mounted piston riding along an air flow controlling cone internal to the body, a vacuum guage mounted on the housing, and a reading scale on the housing that is calibrated with the spring and cone for indicating flow rate upon spring-loaded deflection of the piston. A plate or valve is attached to the housing and movable between open and closed positions to prevent air flow through the meter to measure vacuum in the closed position and to permit air flow through the meter to measure both vacuum and air flow rate in the open position.

Abstract: A sensor apparatus includes a pressure sensor, a reference device and a temperature sensor collocated within a common environment. The reference device and the temperature sensor are constructed to have temperature response times matched to the temperature response time of the pressure sensor to compensate for temperature gradients produced either by external heating or by pressure-volume heating.

Abstract: A pressure measuring instrument for the measurement of the combustion chamber pressure in a cylinder of an internal combustion engine, comprises a piezoelectric pressure sensor. The sensor includes an annular disk-like electrode with an output terminal, a piezoelectric element in contact with said electrode, a pair of annular pressure acting members having interposed therebetween said electrode and said piezoelectric element, and a lead. The piezoelectric pressure sensor is disposed between a first wall on a cylinder head and a second wall of a spark plug.

Abstract: A brain ventricle shunt system having a first catheter to be inserted into brain ventricle, a second catheter to be inserted into another part of a human body, and a shunt main body connected at one end thereof to the first catheter and at the other end to the second catheter. A check valve is provided for preventing cerebrospinal fluid from flowing back from the second catheter to the first catheter. The shunt main body has a reservoir formed therein and communicated with the first catheter to store the cerebrospinal fluid therein. A dome-shaped flexible portion is formed on the shunt main body and defining the reservoir. The dome-shaped flexible portion is provided to be upwardly projected from the shunt main body by pressure of brain ventricle and provided to be pressed through a scalp by a rod of an external pressure sensor to compress the reservoir.

Abstract: A spark plug with pressure sensor comprising; a center electrode having a high voltage terminal; an insulator provided around said center electrode to securely support it; a tubular metallic shell provided to support said insulator at its inner side; a pressure sensor having a piezoelectrical element at least enclosed by a casing of a metallic hollow ring; the metallic shell having a diameter-increased portion and a diameter-reduced portion; the casing of the sensor being inserted into the diameter-reduced portion with an inner side of the casing tightly engaging the outer side of the diameter-reduced portion; a mount means having a ring portion and a flange portion; the ring portion tightly inserted into the diameter-reduced portion while the flange portion tightly sandwiching the casing with a step between the diameter-reduced portion and the diameter-increased portion; and the ring portion being welded to said diameter-reduced portion to maintain air-tight relationship between an innerside of the ring port

Abstract: A modular switch device includes a housing enclosing an interconnected control module, a display module and a power module. A sensor module supplying analog data signals from one of a temperature or pressure sensing element connects to the control module through a passage in the housing. A user connects his electrical wires and electrical power to the electrical assembly within the housing through an opening. The user can select between AC and DC switched output modules and the presence or absence of a 4-20 milliampere output module by plugging and unplugging same from wells provided in the housing. The manufacturer and user thus can modify the standard housing, which includes an internal electrical assembly to be a pressure or temperature switch and to provide selected output switch characteristics by applying and removing selected sensor and output modules thereto.

Abstract: A multiple location negative air pressure monitor is provided which enables the air pressure within a work space to be monitored at various locations throughout the work space so that the site operator is assured that the proper negative air pressure is maintained throughout the work area.

Abstract: An osmometer for use in the measurement of gases, liquids and solids is disclosed. The osmometer includes a semipermeable hollow fiber, capable of passing liquids but not dissolved solids. The hollow fiber contains a media component with a predetermined osmolarity compatible with the sample to be measured. A gas volume is also contained within the hollow fiber and a sensor is present and located adjacent to the gas volume. The sensor is responsive to changes in the gas or media volume due to changes in the media component caused by the influx or efflux of water to the hollow fiber.

Abstract: A gauger for a car includes a housing having a tubular receiving room, a gauge head having an air inlet and an axial projection capable of being urged against a car air valve, a pressure-measuring plunger slidably received in the receiving room, a piston engaging with the plunger for being forced by an air pressure to protrude plunger from the receiving room, an elastic member mounted for returning the piston to rest against the gauge head when the projection is removed from the air valve, two conducting members respectively mounted on the gauge head, and a circuit device electrically connected to the conductive members and capable of showing an electrical power state of a car battery. Such gauger is also designed to detect the wearing degree of a tire tread.

Abstract: A medical infusion pump includes a housing (10), a pump assembly (30), a bubble sensor assembly (120), a pressure sensor assembly (140) and a flow control assembly (180). The pump assembly includes a ring (26) with teeth (44) and a wheel (46) mounted for eccentric rotation within the ring. The pumping action is developed by the rotation of the wheel which continuously closes a portion of tubing (36) against one or two teeth as it goes through the pumping cycle. The bubble sensor includes a pair of sensor blocks (124) defining a generally V-shaped trough for cradling a portion of the tubing. The pressure sensor assembly detects pressure variations by movement of a diaphragm (168) coupled to a magnet (162) which is operatively coupled to a Hall effect circuit (160). The flow control assembly includes a thumb wheel (196) having a cam groove (197) interacting with a valve stem (199) for controlling the fluid flow through an orifice and associated valve seat (194).

Abstract: A unique combination of two transducers. A hot film shear stress gauge and a piezoelectric pressure transducer are coaxially located along the longitudinal centerline of a cylindrical metal shell. The hot film shear stress gauge is exposed to the fluid while the pressure transducer is positioned directly below. Conductors are attached to each and the remaining volume filled with plastic to form a colinear unit. The conductors attached to the hot film element provide power while the conductors attached to the piezoelectric transducer transmit pressure produced electrical signals therefrom. The resulting configuration allows the measurement of fluctuating shear stress and fluctuating pressure to be made simultaneously at a single spatial location at a solid wall bounding a turbulent fluid flow layer.

Abstract: The invention involves the design of a miniaturized piezoelectric pressure ransducer used for measuring pressure-time characteristics in gun tubes during the propellant ignition and burning process. The transducer utilizes a Z-cut tourmaline crystal as the piezoelectric pressure sensing element which produces a finite amount of electrical charge (normally expressed in picocoulombs) for a given change in pressure. The tourmaline crystal is incapsulated in a mechanical fixture which provides means for mounting in the gun tube. Electrical terminals are provided for connnecting to signal conditioning and recording instrumentation. Insulators are provided for electrically insulating the pressure sensing element from weapon ground.

Abstract: Air data measurement apparatus for use on an aircraft, comprises a housing (1) open at both ends (2, 3) and divided into two chambers (8, 9) by a transverse wall (7). The leading end chamber (8) contains a total pressure sensor (11) and the trailing end chamber (9) contains a total temperature sensor assembly (15) whereby the apparatus functions to measure total temperature and pressure at a common point on an aircraft.

Abstract: A capacitive pressure sensor suitable for making highly sensitive, low pressure measurements is disclosed. The sensor may be mounted into a 0.5 mm OD catheter suitable for multipoint pressure measurements from within the coronary artery of the heart. The sensor employs a transducer which consists of a rectangular bulk silicon micro-diaphragm several hundred microns on a side by two microns thick, surrounded by a supporting bulk silicon rim about 12 microns thick. Both the diaphragm and the rim are defined by a double diffusion etch-stop technique. The transducer fabrication process features a batch wafer-to-glass electrostatic seal followed by a silicon etch, which eliminates handling of individual small diaphragm structures until die separation and final packaging. An addressable read-out interface circuit may be used with the sensor to provide a high-level output signal, and allows the sensor to be compatible for use on a multisite catheter having only two electrical leads.

Abstract: According to the invention, a single structure is provided to both produce pressure in and evacuate a space. The inventive device has a barrel with a chamber and separate vacuum and pressure passageways in communication with the chamber. A check valve is mounted in the vacuum passageway to permit flow of air into the chamber through the vacuum passageway but to prohibit flow out of the chamber through the vacuum passageway. A second check valve is mounted in the pressure passageway to permit flow of air out of the chamber through the pressure passageway but to prohibit passage of air through the passageway into the chamber. A plunger is movably mounted in the chamber to selectively develop pressure in the chamber and pressure passageway upon being moved in a first direction and to draw air from the chamber and evacuate the vacuum passageway upon being moved opposite to the first direction.

Abstract: An improved SCUBA diving gauge. A pictograph display is provided which has a shape which conveys the type of information being displayed. The pictograph has the shape of a SCUBA tank for a tank pressure display and the shape of a person for a display of nitrogen absorbed. Pressure transducers coupled to the SCUBA tank and the external water provided the pressure readings required to produce the respective displays. The differential signal from the transducer is supplied to a processor through an auto-zeroing circuit. The auto-zeroing circuit uses a capacitor initially coupled to an amplifier reference input and single ended output to store an offset voltage. During a measurement, the capacitor is disconnected from the amplifier output and has its other lead coupled to a full scale value of the differential input to produce an output signal which is a ratio.

Abstract: Apparatus for measuring the drop height of a container by detecting changes in altitude pressure resulting from the drop of the container. The apparatus includes transducers for measuring absolute temperature, atmospheric barometric pressure, and the differential pressure between the release elevation and the impact elevation.

Abstract: Method and apparatus are provided for simultaneously measuring temperature and pressure in a class of crystalline materials having anisotropic thermal coefficients and having a coefficient of linear compression along the crystalline c-axis substantially the same as those perpendicular thereto. Temperature is determined by monitoring the fluorescence half life of a probe of such crystalline material, e.g., ruby. Pressure is determined by monitoring at least one other fluorescent property of the probe that depends on pressure and/or temperature, e.g., absolute fluorescent intensity or frequency shifts of fluorescent emission lines.

Abstract: A transducer assembly having a housing provided with an inlet port which is adapted for communication with an exhaust passage of an internal combustion engine. The housing includes at least one pressure chamber to which the inlet port opens and an apparatus for detecting pressure in the chamber. The inlet passage to the chamber being subject to ice blockage when ambient temperatures fall below freezing. As such, an apparatus which extends at least partially through the inlet passage is provided to prevent complete ice blockage of the inlet passage whereby assuring proper performance of the transducer assembly.

Abstract: An improved SCUBA diving gauge. A pictograph display is provided which has a shape which conveys the type of information being displayed. The pictograph has the shape of a SCUBA tank for a tank pressure display and the shape of a person for a display of nitrogen absorbed. Pressure transducers coupled to the SCUBA tank and the external water provide the pressure readings required to produce the respective displays. The differential signal from the transducer is supplied to a processor through an auto-zeroing circuit. The auto-zeroing circuit uses a capacitor initially coupled to an amplifier reference input and single ended output to store an offset voltage. During a measurement, the capacitor is disconnected from the amplifier output and has its other lead coupled to a full scale value of the differential input to produce an output signal which is a ratio.

Abstract: Several specific types of optical sensors capable of measuring temperature, pressure, force, acceleration, radiation and electrical fields, fluid level, vapor pressure, and the like, are disclosed, along with an electro-optical system for detecting the optical signal developed by the sensor. One such probe utilizes a convex shaped structure consisting of an elastomeric material attached to an end of an optical fiber, the elastomeric material being coated with a luminescent material, a combination that is capable of measuring both temperature and pressure. Such a probe is also specifically adapted for measuring surface temperature by making a good physical contact with the surface being measured. Another such probe utilizes a similar structure but of a non-elastomeric material for the purpose of detecting both temperature and either index of refraction of vapor pressure changes.

Abstract: Regarding a gas pressure gage for measuring a gas pressure in a vacuum chamber of a semiconductor element manufacturing apparatus, or the like, the present invention has made it possible to attain a small-sized and unitary gas pressure gage and to implement a thorough measurement of gas pressure from the atmospheric pressure to a high vacuum of about 10.sup.-10 Torr, by mounting both a mechanical vibrator type pressure gage and an ionization type pressure gage on a flange provided for fitting a chamber and by providing a control circuit for making the former gage operate in a low-vacuum region and the latter in a high-vacuum region.

Abstract: A method and apparatus are disclosed for deriving digital signals from analog variations of different sensing elements in a transducer. Each sensing device controls the frequency of a variable frequency oscillator, which is energized when a reading is to be taken for that specific sensing device. The periodic signal is coupled to a first counter which counts a presettable total number of cycles so as to establish a variable time period proportioned to the value represented by the then existing state of the sensing device. Concurrently, a second counter is operated for a like time interval, but counts cycles from a fixed frequency clock source at a much higher frequency. The number of cycles counted by the second counter is proportional to the analog signal from the sensing device. This arrangement enables the analog signals from the sensing devices to be digitized in sequence with compact circuitry having low power drain.

Abstract: A conduction-responsive meter head has a device having electrical conduction responsive to a condition such as pressure to be metered. The device communicates with the condition to provide its electrical-conduction response to a bridge electrically including the device. A power supply has two terminals on the meter head for providing electrical power to the bridge. The measurement signal from the bridge is provided, however, to a third terminal by a lead from the bridge.

Abstract: A diaphragm pump is provided for pumping paint and similar substances at relatively elevated pressures (300 psi). A pressure sensor is provided for operating the pump in order to maintain the desired pressure. The pressure sensor is located adjacently first outlet passage and is provided with a deflector which deflects the fluid in the outlet passage over the surface of the sensor diaphragm. By providing continuous flow over the face of the sensor diaphragm, paint and similar substances are prevented from drying and/or clogging thereby preventing erratic operation or failure of the device. The connecting rod which is attached to the diaphragm has an outwardly extending and downwardly tapering support surface which supports the diaphragm when under the elevated pressures of which this unit is capable of operation. An upper support member is also provided for further support.

Abstract: A marine riser anticollapse valve is disclosed for preventing a marine riser from collapsing under external sea water pressure in the event of a sudden loss of internal drilling fluid pressure. An external valve structure is provided for each of a plurality of openings in the wall of a riser pup joint. Each of the valve structures includes a cylinder having an opening in communication with a body wall opening. A piston in each cylinder is subject to sea water pressure but is prevented from opening when riser bore pressure of a sufficient magnitude is applied internally to the piston via the pup joint opening and cylinder opening. When the riser bore pressure falls, the piston is driven to an open position allowing sea water to enter the riser.

Abstract: A coding circuit comprises an astable multivibrator which transforms the measurement of the variables in question, for instance pressure and temperature, into a time measurement. The astable multivibrator delivers a pulse signal whose pulse width is a function of the temperature and the cyclic ratio of which is a function of the pressure.

Abstract: Apparatus is described which is adapted to analyze various operating conditions and characteristics of steam cleaners and pressure washer (e.g., of the type which heats water and forces it out of a nozzle under pressure). The test apparatus includes means for testing and analyzing operating characteristics and parameters such as inlet and outlet water temperature, water pump head pressure, coil outlet pressure, fuel pressure, water flow rate, voltage and electrical current draw, stack temperature, and hydrocarbon emissions. The test apparatus is useful in servicing pressure washers and in comparing the operation of one pressure washer to another pressure washer. The test apparatus is also very useful in detecting possible safety hazards existing in steam cleaners and pressure washer.

Abstract: A tool which is designed primarily to be used by truckers, which takes the form of a housing, one end of which terminates in a graspable handle and the other end of which terminates in an operating head. Within the graspable handle there is located an air pressure gauge. Within the operating head, there is located a valve assembly. The valve assembly is to be connectable to a source of pressurized air which is to be conducted through an air passage assembly within the housing to an air pressure gauge. The air pressure operates an inflation valve of the air pressure gauge and visually displays a value corresponding to the amount of air pressure. The operating head includes a groove arrangement permitting mounting thereon of an accessory tool. The valve assembly is movable relative to the operating head.

Abstract: A temperature-compensated Bourdon tube gauge for indicating a parameter of a pressurized fluid, including a support structure, a Bourdon tube having an open fixed end receiving the fluid and a free closed end carrying an indicating member, a dial member carrying a parameter scale disposed along the path of motion of the indicating member, and a temperature-responsive element for moving the dial member in accordance with a sensed temperature such that the indicating member indicates the fluid parameter on the dial member scale. The temperature-responsive element comprises a bimetallic element connected between the support structure and the dial member. The bimetallic element may be connected to the dial member by a lever having a "variable fulcrum" which varies along the length of the lever in accordance with the shape of a cam with which the lever is maintained in contact.

Abstract: A pressure transducer of the type providing a continuous electrical output signal indicative of the variation in sensed pressure having a metallic preferably aluminum armature attached for movement with a resilient pressure responsive diaphragm. A resonant circuit includes a coil disposed adjacent the armature and an oscillator provides current flow in the coil which generates eddy currents in the armature; and, movement of the diaphragm and armature causes the eddy currents therein to alter the effective inductive reactance of the coil and shift the frequency of resonance of the circuit. Circuit means are provided to emit an output signal indicative of the frequency shift for enabling a continuous determination to be made of the sensed pressure on the diaphragm. An auxiliary snap-action switch is provided remotely from the diaphragm and is actuated by a non-metallic rod from the armature passing through the central region of the coil. The circuitry is preferably mounted on a p.c.

Abstract: A pressure-biased, temperature sensor means utilizing a cooperating pair of aligned bellows operators in a chamber communicating with a fluid system. One of the bellows expanding in response to an elevated temperature of said fluid and the second bellows expanding in response to a decrease in fluid pressure. Both of the bellows operate to move a diaphragm operator to close a switch means in a signal circuit thereby completing the circuit and energizing a signal means.