Abstract: A device for measuring the pressure and temperature of fluids is provided, which has a temperature-sensitive element and a pressure-sensitive cell which are arranged connected to an electronic circuit, connected to which, in turn, are terminals of a connector by which a metal body is closed, in which the element and the cell are housed; the cell being housed in a cavity defined on one side of a plastic body through which electric conductors pass, which connect the element to the electronic circuit; the cell resting on a seal disposed between the cell and the base of the cavity, a wedge element placed over the cell which rests against the cell to compress the seal to thereby provide a seal around the mouth of a conduit through which the pressure of the fluid to be controlled is transmitted onto the cell.

Abstract: In a resistively heated heat-loss pressure gauge, electrical current is switched between a sensing element and a compensating element at different duty cycles. As a result, the sensing element is heated relative to the compensating element. A fixed resistance is placed in series with at least the compensating element. The current source applies current to heat the sensing element to a temperature at which the resistance of the sensing element matches the combined resistance of the compensating element and the fixed resistive element.

Abstract: The digital air pressure gauge includes an error correction lookup table database stored within a memory device within the gauge. The database includes reference air pressure values and associated measured air pressure values, where the reference air pressure values and associated measured air pressure values are determined at identical discrete time intervals as pressurized air is input into the gauge. A transducer generates an electrical signal representative of air pressure within a device such as a pneumatic tire. A microprocessor compares the electrical signal with measured air pressure values within the database and determines a closest measured air pressure value. The microprocessor then determines the associated reference air pressure value of the closest measured air pressure value. The reference air pressure value is then displayed as the accurate pressure of the pressurized air within the device. The gauge may be disposed within a tire valve cap with an RF transmitter.

Abstract: A hydraulic pressure sensor for measuring the pressure in a hydraulic pressure chamber 1. A reservoir housing 9 is connected to the pressure chamber, and the interior of the housing is divided by a slideable partition 13 which defines a reservoir chamber 8 which is connected to the pressure chamber and a sensor chamber 7 which is connected to a sensor element 5. The partition 13 is constructed as a piston and extends for sliding movement along the walls of the reservoir housing while exerting a frictional force. A spring 11 supports the partition relative to the reservoir housing against the pressure in the reservoir chamber 8. The partition 13 may be constructed as a differential piston, and consist of two or more piston sections 13.1, 13.2, 13.3, which extend independently of one another in a sliding and sealing manner, and mutually support one another by an intermediate spring 14.

Abstract: A novel method for interconnecting leads in a high pressure transducer without the use of solder employs a ceramic disc containing a number of through holes. Each hole has a tube inserted therein, which tubes are connected to the disc by brazing or a high temperature attachment. Each tube protrudes from both sides of the ceramic. The ceramic is coated in appropriate areas with molymanganese film, which is over plated with gold. This overcoat forms a brazed compound surface attached to the tubes of the ceramic. A semiconductor pressure transducer has output leads which are inserted through the ceramic into each tube. The other side end of the tube receives high temperature wires from a suitable connecting device. Each tube is then crimped and spot-welded to hold both the lead from the transducer and the high temperature leads to produce a strong bond without the use of solder. The header itself it typically welded to a pressure point.

Abstract: Techniques are disclosed for improving pressure sensor shock robustness in fluid containment devices by providing a mechanical filter configured to prevent high-frequency pressure shocks from damaging the pressure sensor. One approach includes a body of elastomeric material disposed on an external surface of the sensor. Another approach is a porous plug in a fluid pathway leading to the sensor. Yet another approach is to provide a seal structure with a labyrinth fluid path.

Abstract: Apparatus for generating a dynamic force response that simulates a dynamic force typically generated by an experimental event. A cam having a profile, such as a serrated profile, rotates about an axis according to a rotational speed profile. A braking device operatively connects to the cam, such as a follower biased against the cam, for generating a braking force resisting rotation of the cam. A measurement device measures the braking force on the cam to generate the dynamic force response.

Abstract: A force sensor for sensing the weight of a vehicle seat occupant for a vehicle's occupant protection system has a pressure sensor responsive to hydraulic pressure resulting from axial force applied to the force sensor. A constant force spring in the form of a diaphragm with two flanges simultaneous functions as a seal, a constant force bias spring, an armature support resistant to radial forces and a piston for converting force to hydraulic pressure. Two studs receive applied force. An electrical insulator is sealed to the walls of a passage inside of one of the studs to provide electrical communication while sealing against liquid leakage. A pressure sensor is mounted on the electrical insulator and connected to electrical conductors in the insulator by stitch bonding. The diaphragm resists radial movement while allowing axial movement thereby making the sensor insensitive to radial forces. By being a constant force spring the diaphragm makes the sensor insensitive to temperature variations.

Abstract: Apparatus is provided for sensing the pressure and temperature of fluid within a cavity of a block, such as hot plastic that flows into a mold cavity. The apparatus includes a piston (30) lying closely but slideably within a bore that extends from the cavity in the block. The outer end of the piston is coupled through a beam structure (36), in a shape of a diaphragm, to a rigid support (40). A strain gauge (44) mounted on the diaphragm senses piston deflection which is proportional to the pressure of fluid in the cavity. A highly heat conductive rod (80) extends through a hole in the middle of the piston, the rod having an inner end (84) that is flush with the piston and the rod having an outer end (86) joined at a thermocouple joint (92), so the temperature of the rod is sensed by the thermocouple to thereby sense the temperature of material in the cavity.

Abstract: A motion transducer having a user moveable plunger which compresses a spring for generating a force proportional to plunger displacement and applying the generated force to an actuator telescoped onto the plunger. The actuator has an elastomeric pad on the surface which contacts and reacts the generated force onto a force/pressure sensitive resistive strip which varies its resistance with the changing force applied by the elastomeric pad. The changes in resistance may be electrically detected to give an indication of plunger travel.

Abstract: A catheter that is guided into an intra-corporeal passageway is set forth. A catheter tube accommodates an element having a piston for detecting a pressure in the intra-corporeal passageway. Silicone gel is accommodated in the catheter tube to transmit the detected pressure in the catheter tube. A strain gage is disposed on a semiconductor chip to output an electric signal based on an amount of a deformation thereof indicative of the pressure in the catheter tube.

Abstract: An indicating device includes a housing that is separated into two sub-chambers by a flexible diaphragm. A indicating member is carried by the diaphragm so that the diaphragm and the indicating member move, within the housing, responsively to changes in the pressure of the air flowing through an air intake system caused by restrictions in or clogging of the air intake filter. The indicating device incorporates an electromechanical sensor for monitoring the position of the diaphragm and producing an output signal responsive thereto. In one embodiment, the sensor is a potentiometer which produces an output signal which varies continuously between a first value when the diaphragm is at its unrestricted position and a second value when the diaphragm is at its restricted position. In a second embodiment, the sensor includes a switching circuit which produces a switched output signal which varies between at least three states corresponding to three different diaphragm positions.

Abstract: A pressure sensor die is provided with a flexible membrane and a plunger which combine to amplify a low pressure signal while also providing media isolation between a fluid being measured and the internal components of a pressure sensor. One embodiment of the pressure sensor disposes an end of the plunger in direct contact with a pressure sensor die while another embodiment disposes an elastomeric diaphragm between the plunger and the pressure sensor die. This second embodiment creates a chamber between the plunger and the pressure sensor die in which a fluid is captured by movement of the plunger. The captured fluid is decreased in volume by movement of the plunger and the resulting increase in pressure in transmitted to a pressure sensitive portion of a pressure sensor die. The device is particularly useful in conjunction with applications where media isolation is required between the fluid being measured and the components of the pressure sensor, such as kidney dialysis machines.

Abstract: A device for determining a pressure of gas in an evacuated chamber including a cylinder positioned in fluid communication with the evacuated chamber with the cylinder forming a compressed gas chamber, a reciprocating piston received within the cylinder and mounted for reciprocal movement therein, a port or valve for providing selective fluid communication between the compressed gas chamber and the evacuated chamber is disclosed. A drive mechanism is provided for reciprocating the piston between a retracted position, where the compressed gas chamber communicates with the evacuated chamber, and an extended position where communication between the compressed gas chamber and the evacuated chamber is interrupted, the position being a position where a pressure transducer determines that a predetermined pressure differential between the chambers has been reached.

Abstract: An integral pressure sensor for a pressurized vessel, including a housing, a core element, a seal and a spring. This combination is disposed on the interior of the pressurized vessel. The core element is preferably a magnetic element or a steel ball which moves in the housing under the effect of the vessel pressure, and the chamber or housing pressure. The spring and seal combination together with the core element, function to trap a specified volume of the pressurized medium in the chamber when the vessel is initially pressurized. When the pressurized vessel leaks, the trapped pressure within the chamber exceeds the vessel pressure thereby causing the core element to move. The position or presence of the core element is detected using a detecting device such as a Hall-effect device or another magnetic device.

Abstract: A digital tire pressure gauge comprises a pressure measuring head to introduce thereinto the tire air. The pressure measuring head extends axially to form a tubular body in which a pressure bearing rod encased by a coil spring is received. The pressure bearing rod is coupled with a pressure converting unit serving to convert the displacement distance of pressure bearing rod into an electronic signal. A pressure displaying unit is connected with the output terminal of the pressure converting unit so as to exhibit thereon in digital form the electronic signal transmitted from the pressure converting unit.

Abstract: An improved pressure transducer to measure and indicate fluid pressure levels including a housing in which a piston assembly is movable in response to pressure changes, the housing being of a composite material of metal and plastic and having grooves therein, the piston having bosses formed thereon to be engaged within the grooves of the housing to prevent rotation of the piston. The transducer is also designed to facilitate grounding of an electrical contact assembly located within the housing. The external portion of the housing may be formed in a hexagonl shape to facilitate installation and removal of the unit.

Abstract: An apparatus and method for measuring differential pressure of mud internal a drill string and mud in a borehole annulus is disclosed.

Abstract: A pressure transducer to measure and indicate fluid pressure levels including a housing in which a diaphragm and piston assembly is movable in response to pressure changes, the piston having a portion extending therefrom to engage a switch contact thereby disengaging the switch when the fluid pressure falls below a desired level.

Abstract: Force or pressure measuring device. Between a support member and a force or pressure introduction member elastomeric material is provided which strongly adheres to the two members and is in contact with at least one pressure sensor. With a preferred embodiment the support member is in a potlike form while the force or pressure introduction member is in the form of a piston received by the support member and forming a very narrow gap to the cylindrical surface thereof which gap is essentially completely filled by said elastomeric material.

Abstract: A fluid pressure transducer having a hollow enclosure with an elongated tubular guide supported therein around which a tubular piston moves in response to fluid pressure forces acting on one piston end. A spirally-wound wire resistance coil on the guide is contacted by one end of a conductor carried by the movable piston to effectively charge resistance through the conductor and parts of the coil. The conductor is connected to one end of a metal spring which opposes piston movement due to pressure forces. An opposite end of the metal spring is connected to a terminal to transmit the resistance changes.

Abstract: A tocodynamometer for measuring intra-amniotic pressure through the abdominal wall of obstetric patients, including a force transducer resiliently mounted in a housing, a precompressed coil spring between the housing and an outer backplate, and an attachment on the outer backplate for fastening thereto a belt tensioner for holding the apparatus against the patient adjacent the uterine wall.

Abstract: A transducer for establishing an output voltage proportional to an input fluid pressure supplied thereto. The transducer has a resistor with a voltage selector movable in electrical contacting engagement therewith to establish the output voltage. A piston actuates the voltage selector to its electrical contacting engagement with the resistor to establish the output voltage in response to the input fluid pressure acting on a diaphragm arranged in driving engagement with the piston.

Abstract: A hydraulic pressure transducer comprises a cylindrical housing having a plurality of circumferential inwardly and outwardly directed ribs which axially position and retain coaxially aligned operative components within the transducer. These components include a hydraulic piston and cylinder, a restoring spring disposed between two centering and retaining stabilizer cups, and a biasing spring which maintains the components in compressed juxtaposition to ensure accurate and immediate response while minimizing axial dimensional stack up. The transducer senses hydraulic pressure in, for example, a brake line and provides a variable resistance output which may be used in an auxiliary electric brake system controller commonly used on recreational trailers and the like.

Abstract: A pressure measuring device for measuring absolute or differential pressure has a hollow carrier, with a deformable measuring bar extending across the opening in the carrier. A transducer is fixed on the bar and converts deformation of the bar to electrical signals. The bar has weakened portions of reduced cross-section at four spaced positions thereon, in order to define the manner of deformation of the bar. A rigid piston connected to the bar substantially centrally thereof is sealingly displaceably guided in a pressure-receiving chamber whereby the piston is subjected to the pressure to be measured and thereby causes deformation of the bar, with the resultant production of electrical signals representing the pressure.

Abstract: A hydraulic pressure transducer comprises a cylindrical housing having a plurality of circumferential inwardly and outwardly directed ribs which axially position and retain coaxially aligned operative components within the transducer. These components include a hydraulic piston and cylinder, a restoring spring disposed between two centering and retaining stabilizer cups, and a biasing spring which maintains the components in compressed juxtaposition to ensure accurate and immediate response while minimizing axial dimensional stack up. The transducer senses hydraulic pressure in, for example, a brake line and provides a variable resistance output which may be used in an auxiliary electric brake system controller commonly used on recreational trailers and the like.

Abstract: A device for sensing and/or measuring fluid pressure which includes a pressure-sensing tube elongating as a function of fluid pressure therein, a non-expanding member connected to the tube and extending in generally parallel relation thereto and terminating short of a free distal end of the tube, and an electric resistance strain gage connected to and spanning the distance between the distal end of the tube and the adjacent end of the non-expanding member, the combination functioning to provide a mechanically amplified motion at the strain gage with excellent lineal signal to pressure response.

Abstract: A high pressure transducer includes a first disk member having positioned on a surface, a square piezoresistive bridge array. Located above and coaxial with the first disk member is a second member of a substantially greater thickness. The second member has a plurality of apertures in alignment with the terminal areas contained within said bridge pattern. The apertures accommodate leads which are directed from the bridge pattern on the first disk to utilization means for monitoring transverse variations in the bridge when operating in a high pressure environment.