Abstract: A pressure sensing transmitter is provided that has high overpressure protection. The transmitter includes an housing having a first cell, a second cell, a sensing chamber, first and second pressure signal receiving means, and a differential sensor chip for measuring the pressure differential between the first and second pressure signal receiving means. Each cell further includes a cylinder with a clearance of an overpressure diaphragm mounted on the housing, an isolation diaphragm mounted on the other face, and a channel coupling the overpressure and isolation diaphragm and further coupling one cell to the first pressure signal receiving means and the other cell to the second pressure signal receiving means. Each overpressure diaphragm is positioned such that an overpressure protection cavity is formed between it and the housing. The first cell cavity is further coupled to the second pressure signal receiving means and the second cell cavity is further coupled to the first pressure signal receiving means.

Abstract: Methods and apparatus for operating an optical communications system having at least two communicating entities (10,12). In accordance with a method of the invention a first step transmits communication link control information from a first entity to a second entity over a first optical channel having a first data bit rate. Responsive to the transmitted communication link control information, a second step of the method transmits data information from the second entity to the first entity over a second optical channel having a second data bit rate that is greater than the first data bit rate. The first optical channel is preferably a relatively low-bandwidth diffuse transmission infrared radiation channel. The second optical channel is preferably a relatively high-bandwidth infrared channel. One of the entities is a network adapter coupled to a wired network. The network adapter is preferably ceiling mounted. The other entity may be a mobile data processor.

Abstract: The invention improves upon the diaphragm/beam-type transducers and method of manufacturing same described in U.S. Pat. No. 4,368,575.The new transducers and method of manufacture utilize strips or slivers of silicon or germanium which are larger than the individual strips used in the apparatus and method described in U.S. Pat. No. 4,368,575 by an amount sufficient to permit (a) the formation of two gages on each strip and (b) the forming of bonding pads on each gage. The bonding pads are formed on the gage strip before the strip is bonded to the beam, so that formation of the bonding pads and bonding of the strip to the beam can be handled automatically. The strips are mounted to one side of the midpoint of the beams, so that when a diaphragm/beam is deflected by application of a fluid pressure, one of the two gages will undergo a tension strain while the other gage will undergo a compression strain.

Abstract: A resistive strain gauge sensor of the type including a circuit board carrying circuitry, a diaphragm bonded to the circuit board, and strain gauge circuitry on the diaphragm. The strain gauge circuitry includes a plurality of leads defining free ends and the circuitry on the circuit board defines a plurality of leads defining free ends. The diaphragm is bonded to the circuit board by a frit layer and the frit layer includes voids which are in respective alignment with the free ends of the strain gauge leads and the free ends of the circuit board leads. A conductive epoxy is positioned in the voids in the frit layer to establish electrical communication between the strain gauge circuitry leads and the circuit board leads without the use of solder joints.

Abstract: A resistive strain gauge pressure sensor including upper and lower housings coacting to define a pressure chamber within the housing. A board member is clamped between the housings and defines a diaphragm portion which extends across the pressure chamber to divide the pressure chamber into upper and lower chamber portions. All of the circuitry of the sensor is screen printed onto the lower planar face of the board member including the various resistor elements of the strain gauge assembly, the various elements of the conditioning circuit receiving the output of the strain gauge assembly, and the various further leads required to connect the circuitry elements to the terminals of the sensor. The sensor terminals are provided by a plurality of connector pins extending downwardly through the board member for connection at their respective lower ends to the circuitry provided on the lower face of the board member.

Abstract: A resonant pressure transducer, having a deformable diaphragm or membrane exposed to an ambient environment wherein a pressure force to be measured exists, is provided. A transducer according to the present invention comprises a converter for transmitting the pressure force experienced by the diaphragm to a resonator vibrated by an exciter whose resonant frequency is a function of the intensity of the ambient pressure force to be determined. The converter and resonator are mounted in a rigid frame. The converter has flexible bending means able to absorb the bending moments resulting from the deformation of the diaphragm, so as to transmit to the resonator a tension or a compression force free from bending moments that generate stresses at the entrance of the resonator.

Abstract: A precision, low cost, capacitor sensor comprised of two parallel plates, with an air dielectric, with preferably both substrates comprised of vitreous materials and electrically conductive coating, but with at least one of the substrates and coating being transparent. The coatings are preferably of identical material, thickness and pattern to offset stress distortion of the sensor plates from thermal expansion and contraction. Uniform spacing between the plates is provided by means of glass fibers of uniform diameter, dispersed in a matrix of adhesive and bonded under pressure, deposited between the plates as two thin semicircular seal rings surrounding the dielectric and separated by a diametrical gap, allowing entrance or escape of air dielectric. A novel feature, provided by at least one plate and coating being transparent, is use of optical measuring techniques during fabrication to verify acceptability of the manufacturing process and uniformity of the sensor product.

Abstract: Low temperature wafer bonding process enhancement makes a wafer surface hydrophobic, preparing it with a buffered oxide etchant and then exposing it to H.sub.2 O.sub.2 before thermoelectric bonding. Has particular application to diaphragm-based pressure sensor construction.

Abstract: A pressure sensor comprises a pair of pressure compartments with deflective end walls and an elongated displaceable member with two extremities respectively anchored to the deflective end walls of the two pressure compartments, and a capacitor with first series of capacitor plates affixed to the elongated displaceable member and a second series of capacitor plates disposed in an alternating arrangement with the first series of the capacitor plates and affixed to a stationary member, wherein the pressure difference between the two pressure compartments displaces the elongated displaceable member in axial directions thereof and changes the capacitance value between the first and second series of capacitor plates and, consequently, the numerical value of the differential pressure is determined as a function of the measured value of the capacitance.

Abstract: A pressure-measuring head for measuring the pressure of a fluid consists of a membrane-like diaphragm (6), which separates a pressure chamber (4) from a reference chamber (7), to which the pressure-sensitive elements, e.g., thick-film resistors or strain gauges, are applied. Under the effect of the pressure in the pressure chamber, these pressure-sensitive elements perform a deflection which is proportional to the pressure occurring in the pressure chamber. An electric contact is switched during simultaneous displacement of the membrane (6) arranged in a sensor housing by a predeterminable distance (19) after a defined pressure value has been reached in the pressure chamber. A measuring head of such a design is also able to assume a swithing function without additional auxiliary energy, besides sending an electrically processable pressure signal.

Abstract: A purge gas pressure monitoring system has a piezometer tube running from a pressure measuring instrument into a medium to be monitored. A temperature detector device extends the length of the piezometer tube. Outputs from the pressure measuring instrument and the temperature detector device are coupled to a central processing device or microcomputer for monitoring the outputs and using the outputs along with stored data to calculate a corrected pressure signal which is corrected for errors including errors arising as a result of variations of the average temperature along the piezometer line from a reference value.

Abstract: Magnetostrictive wire having a low surface-to-volume ratio established by a onstant non-planar cross-section, is helically deformed into contact with a shaft under a stress maintaining the wire in fixed relation to the shaft surface. Magnetic anisotropy is imparted to the wire by twist thereof about its cross-sectional axis while the wire is being helically deformed into contact with the shaft surface to form a torque sensor through which accurate torque detection is achieved.

Abstract: A pressure sensor for detecting pressure in a combustion chamber of internal combustion engines has a housing, a sensor element composed of a piezoresistive material and arranged in the housing, a diaphragm, a punch introducing a pressure to be determined onto the sensor element and located between the diaphragm and the sensor element. The punch has a counterbearing, a hybrid has a base, and a preprocessing circuit has electronic components. The sensor element, the hybrid with its base and the electronic components of the preprocessing circuit are located on the counterbearing of the punch.

Abstract: A pressure sensitive sensor in which a pressure detecting convex portion is formed on the surface of a pressure-sensitive and conductive elastomer sheet, and an electrode is arranged on the reverse side of the pressure detecting convex portion for making it possible to detect a pressure acting in the direction in parallel or in the oblique direction with a slight angle with respect to the surface of a pressure-sensitive and conductive elastomer component. In addition, for obtaining a high detection density, a contact is made up with a face-defined body defining a pressure face, and a contacting convex portion is made to protrude from the face-defined body, where the contact is resiliently supported onto the pressure-sensitive elastomer sheet.

Abstract: A temperature responsive sensor is located in the airflow over the specified surface of a body and is maintained at a constant temperature. An active thermal isolator is located between this temperature responsive sensor and the specified surface of the body. The temperature of this isolator is controlled to reduce conductive heat flow from the temperature responsive sensor to the body. This temperature control includes (1) operating the isolator at the same temperature as the constant temperature of the sensor and (2) establishing a fixed boundary temperature which is either (a) less than or equal to or (b) slightly greater than the sensor constant temperature.

Abstract: Disclosed is an oil-filled pressure gauge leak-stoppage device including a rivet-like rubber gasket and a metal gasket respectively mounted on a plane on the peripheral wall of the casing around an axle hole thereof to seal the gap between the casing and the stem of the gauge, which stem being inserted out of the casing through the axle hole. A plastic gasket is directly molded on a chamfered annular groove on the bottom of the head of each gauge tie screw around its shank to seal the gap between the casing and the respective tie screw.

Abstract: A pressure sensor includes a liquid crystal positioned between transparent, electrically conductive films (18 and 20), that are biased by a voltage (V) which induces an electric field (E) that causes the liquid crystal to assume a first state of orientation. Application of pressure (P) to a flexible, transparent film (24) causes the conductive film (20) to move closer to or farther from the conductive film (18), thereby causing a change in the electric field (E'(P)) which causes the liquid crystal to assume a second state of orientation. Polarized light (P.sub.1) is directed into the liquid crystal and transmitted or reflected to an analyzer (A or 30). Changes in the state of orientation of the liquid crystal induced by applied pressure (P) result in a different light intensity being detected at the analyzer (A or 30) as a function of the applied pressure (P).

Abstract: A luminescent pressure sensitive composition for determining an air pressure pattern includes a binder, preferably a polymer binder, with a luminophore, of which the intensity of luminescence depends on air pressure. The luminophore of which the intensity of luminesence depends on air pressure (active luminophore) is mixed together with an additional luminophore of which the intensity of luminescence has a different dependence on air pressure than the active or reference luminophore.

Abstract: A weather-fastness test method utilizing a novel sample holder and constituted by the steps of fixing the sample to the holder which is provided with metal coils the shape of which varies in accordance with the variation in the temperature of the ambient air and the radiation heat from a light source and which are connected so as to apply a force to the sample as the temperature changes, placing the sample under predetermined conditions, e.g. exposing the sample to radiation by light, to air having a temperature and humidity of predetermined levels, and to rain, while the sample is under repeated tension, compressive force and/or bending stress due to the variation of the shape of the coils and imparted to the sample, and then evaluating the weather-fastness resistance of the sample.

Abstract: A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum florescent display.