Abstract: A two or three axis load cell capable of measuring axial and one or more shear forces is disclosed. The load cell can comprise a force collector connected by one or more connecting rods to one or more cross pieces. The load cell can comprise a single cross piece and can measure an axial force applied to the load cell and at least one component of shear force applied to the load cell. In other embodiments, the load cell can comprise two cross pieces, disposed at disparate angles, to enable the measurement of an axial force and both components of shear force applied to the force collector. The cross pieces are equipped with a means, such as piezoresistive elements to measure their deflection due to the applied forces on the force collector. The connecting rods can be fitted with additional piezoresistors to measure the axial forces on the force collector.

Abstract: The RTD device of the present invention is comprised of a semiconductor substrate and a substantially thin conductive metal layer disposed upon the semiconductor substrate, wherein the conductive metal has a substantially linear temperature-resistance relationship. The conductive layer is etched into a convoluted RTD pattern, which consequently increases the overall resistance and minimizes the overall mass of the RTD assembly. A contact glass cover and a conductive metal-glass frit are placed over the RTD assembly to hermetically seal the RTD. The resultant structure can be “upside-down” mounted onto a header or a flat shim so that the bottom surface of the semiconductor substrate is exposed to the external environment, thus shielding the RTD from external forces. The resultant structure is a low mass, highly conductive, leadless, and hermetically sealed RTD that accurately measures the temperature of liquids and gases and maintains fast response time in high temperatures and harsh environments.

Abstract: A combined wet-wet differential transducer and a gage pressure transducer located in the same housing, comprising a semiconductor chip which comprises a gage sensor chip on one section and a differential sensor chip on a second section. Each sensor chip has a Wheatstone bridge comprising piezoresistors and is responsive to an applied pressure. The gage chip and the differential chip are placed in a header having a front section and a back section adapted to receive a first and second pressure, respectively. The sensors are in communication with first and second pressure ports such that the absolute sensor provides an output indicative of a pressure applied to a first port and the differential sensor provides an output indicative of the pressure difference between the first and second pressure ports.

Abstract: A pressure transducer comprising a corrosion resistant metal diaphragm, having an active region, and capable of deflecting when a force is applied to the diaphragm; and a piezoresistive silicon-on-insulator sensor array disposed on a single substrate, the substrate secured to the diaphragm, the sensor array having a first outer sensor near an edge of the diaphragm at a first location and on the active region, a second outer sensor near an edge of the diaphragm at a second location and on the active region, and at least one center sensor substantially overlying a center of the diaphragm, the sensors connected in a bridge array to provide an output voltage proportional to the force applied to the diaphragm. The sensors are dielectrically isolated from the substrate.

Abstract: A single pressure sensing capsule has a reference pressure ported to the rear side of a silicon sensing die. The front side of the silicon sensing die receives a main pressure at another port. The difference between the main and reference pressure results in the sensor providing an differential pressure output. The reference pressure or main pressure may be derived from a pump pressure which is being monitored. The pump pressure output is subjected to a pump ripple or a sinusoidally varying pressure. In order to compensate for pump ripple, a coiled tube or an adjustable dampening chamber comprising a spiral inlet tube and a volume cavity can be used. The tube length is selected to suppress the pump ripple as applied to the sensor die. In this manner, the pump ripple cannot cause resonance which would result in pressure amplification and which pressure amplification would destroy the sensor.

Abstract: Disclosed herein is an electronic switch that comprises a pressure sensitive bridge array adapted to monitor pressure and activate an indicator when the monitored pressure exceeds a predetermined value indicative of a dangerous condition. The electronic switch further comprises a monitoring circuit adapted to test the overall operability of the pressure sensitive bridge array and its accompanying electronics control circuitry.

Abstract: It is an objective of the present invention to provide a pressure transducer assembly for measuring pressures in high temperature environments that employs an elongated tube which is terminated at one end by an acoustic micro-filter. The micro-filter has a plurality of apertures extending from one end to the other end, each aperture is of a small diameter as compared to the diameter of the transducer and the damper operates to absorb acoustic waves impinging on it with limited or no reflection. To improve the absorption of acoustic waves, the elongated tube may be tapered and/or mounted to a support block and further convoluted to reduce the overall size and mass of the device. A pressure transducer with a diaphragm flush may be mounted to the elongated tube and extend through to the inner wall of the tube. Hot gases propagate through the elongated tube and their corresponding pressures are measured by the transducer.

Abstract: It is an object of the present invention to provide a pressure transducer having a header wherein the header is comprised of a first section and a second section that are offset from each other. Each first and second section has a flexible diaphragm adapted to receive a first and second pressure, respectively. A central channel connects the diaphragms and a pressure sensor, located within the central channel, communicates with the channel and produces an output equal to the difference between the first and second pressures. The resultant device is a low differential pressure transducer which enables one to bring leads from the sensor out while having diaphragms of substantially the same size and diameter, therefore enabling the diaphragms to exhibit the same back pressure and be equally compliant.

Abstract: It is an objective of the present invention to provide a highly sensitive optical pressure sensor that uses a Mach-Zehnder Interferometer to measure pressure. The pressure sensor comprises a deflectable diaphragm including a substantially central boss and channel and an optical waveguide having a first arm and a second arm, wherein the first arm is substantially aligned with an edge of the boss and the second arm is substantially aligned with an edge of the channel, and further wherein the first and second arms contain a periodic array of etched holes to improve the overall sensitivity of the pressure sensor. The pressure sensor further comprises a light source coupled to the optical waveguide for introducing light to the waveguide and a light detector coupled to the waveguide for detecting changes in the intensity of light. The change in light intensity is then correlated to an applied pressure.

Abstract: A combined wet-wet differential transducer and a gage pressure transducer located in the same housing, comprising a semiconductor chip which comprises a gage sensor chip on one section and a differential sensor chip on a second section. Each sensor chip has a Wheatstone bridge comprising piezoresistors and is responsive to an applied pressure. The gage chip and the differential chip are placed in a header having a front section and a back section adapted to receive a first and second pressure, respectively. The sensors are in communication with first and second pressure ports such that the absolute sensor provides an output indicative of a pressure applied to a first port and the differential sensor provides an output indicative of the pressure difference between the first and second pressure ports.

Abstract: It is an objective of the present invention to provide a pressure transducer assembly for measuring pressures in high temperature environments that employs an elongated tube which is terminated at one end by an acoustic micro-filter. The micro-filter has a plurality of apertures extending from one end to the other end, each aperture is of a small diameter as compared to the diameter of the transducer and the damper operates to absorb acoustic waves impinging on it with limited or no reflection. To improve the absorption of acoustic waves, the elongated tube may be tapered and/or mounted to a support block and further convoluted to reduce the overall size and mass of the device. A pressure transducer with a diaphragm flush may be mounted to the elongated tube and extend through to the inner wall of the tube. Hot gases propagate through the elongated tube and their corresponding pressures are measured by the transducer.