Abstract: An apparatus which utilizes solid state piezoresistive strain sensing means to measure the static pressure as well as the differential pressure across a primary element, such as an orifice plate, venturi tube, nozzle or wedge.

Abstract: A strain gauge pressure transducer comprising a housing having an internal pressure cavity across which is mounted a flexible elastomeric diaphragm that separates high and low pressure chambers in the gauge that the housing is arranged to separately connect the sources of high and low pressure, respectively. A range spring in the form of a leaf spring is anchored to the housing cantilever fashion in the high pressure chamber and to one side of the diaphragm to dispose the live length of same, as defined by a clamp device, in overlying relation to the diaphragm, to which the leaf spring live length is connected for deflecting movement thereof by the diaphragm.

Abstract: A digital differential pressure transducer with relatively low sensitivity to common mode line pressure errors. The transducer includes an airtight enclosure having a pair of pressure ports through which pressure is coupled to opposite sides of a pressure-sensing diaphragm or bellows. The force generated by the pressure differential across the diaphragm or bellows is coupled to a stress-sensitive resonator either directly or through a force-transmitting structure. A first bellows extends from the diaphragm or a bellows end cap. The first bellows has an effective area which is substantially smaller than the effective area of the pressure-sensing diaphragm or bellows so that it applies substantially less pressure-induced stress to the resonator than does the pressure-sensing diaphragm or bellows. A second bellows has an effective area and a mounting position chosen to counteract the effect of the first bellows on the pressure-sensing diaphragm or bellows.

Abstract: In a differential pressure transducer, of the type having a cantilever beam mechanically linked to a pressure-sensitive diaphragm, and piezoelectric strain gauges diffused into or bonded onto the beam, the beam has a relatively high compliance as compared with the diaphragm to facilitate operation in low pressure ranges and to increase the overall operating range of the unit. In addition, the beam is constructed so that the total bending energy is transmitted to the area of the strain gauges so as to achieve near-perfect operating efficiencies.

Abstract: A pressure transducer for automobiles comprises a closed housing, a member for detecting the pressure in the suction pipe of an engine and converting the pressure detected into electric signals, an amplification circuit disposed in the closed housing, and an air passage. The air passage communicates with the atmosphere, but prevents water from penetrating therethrough into the closed housing. The air passage comprises an air hole formed in a member defining the closed housing about terminals provided for leading the electric signals out of the closed housing.

Abstract: A liquid filled pressure pick-up or transducer comprises a housing, as strain gage sensor is supported in a liquid filled cavity in the housing and a membrane extends across an opening in the housing. A force transmitting rod connects the membrane to the strain gage sensor. In order to avoid damage especially to the membrane by extreme excess pressures, a plastically deformable support member acting as a stop is operatively held in the housing substantially in parallel to the membrane whereby the rod extends with play through the support member. An elastic seal extends around the rod hole in the support member toward the membrane. A substantially mirror symmetrical arrangement of two membranes and two support members results in a differential pressure transducer.

Abstract: A differential pressure transducer having a cantilever and a semiconductor strain gauge attached to each side of the cantilever at an intermediate portion of the latter. The cantilever has one end fixed by electron beam welding to a fixing member and the other end left for free displacement in response to a differential pressure. The displacement of the other end of the cantilever is detected as changes in the electric resistances of the semiconductor strain gauges.

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 transducer which includes a metal strain gage material formed on a flexible monocrystalline silicon diaphragm is disclosed. The transducer is fabricated to a large extent with semiconductor processing steps. Gold is diffused into a platinum-tungsten gage material. This allows the gage material to be chemically etched in the presence of other metals to define the active gage resistors. In the presently preferred embodiment, these resistors are formed over thin areas of the diaphragm to provide increased linearity and sensitivity.

Abstract: A pair of semiconductor diaphragm blocks, each having a diaphragm on a front surface of which a diffused resistor is formed as a pressure-sensitive element, and a circumferential support integral therewith, are confined within a sealed hollow package and bonded at their circumferential supports to opposite inside surfaces of the package such that the front surfaces of the diaphragms are positioned within a vacuum space within the package. This package is provided with through holes through which fluid pressures subject to measurement are introduced so as to arrive at the back surfaces of the diaphragms.

Abstract: A differential pressure to electrical signal transmitter has a pair of barrier diaphragms and a central control diaphragm located between the barrier diaphragms. Input fluids are applied to respective chambers on the outside of the barrier diaphragms while the chambers between the control diaphragm and the barrier diaphragm are filled by corresponding substantially incompressible fill liquids. The fluid pressure of the two fill fluids are conducted by corresponding fluid channels to respective sides of a displacement sensing element to produce an electrical signal representative of differential pressure. The control diaphragm is biased by spring loaded spacers located on corresponding sides of the control diaphragm. The spacers have fluid passages to permit the respective fill fluids to reach the control diaphragm.

Abstract: A differential pressure to electrical signal transmitter has a pair of barrier diaphragms and a pair of nested internal control bellows located between the barrier diaphragms. A first internal volume defined between one barrier diaphragm and a corresponding mating support plate in the transmitter body is pressurized with a first fluid, and a second internal volume defined by the other barrier diaphragm and a respective mating support plate in the transmitter body is pressurized with a second fluid. The first volume is connected by a first fluid of conduit to a first chamber of a differential pressure sensor and is filled with a first incompressible fill fluid. The second volume is connected by a second fluid conduit to a second chamber of the sensor and is filled with a second incompressible fill fluid. The pressures of the two fill fluids act on opposite sides of the differential pressure sensor whereby an electrical output signal is produced dependent on the difference between the fill fluid pressures.

Abstract: A pressure sensor comprises essentially magnetoresistive elements formed on a diaphragm serving as a stress magnifier. The diaphragm may be made, for example, of glass in a thickness of 0.5 millimeter, and the magnetoresistive elements can be formed thereon in any desired pattern of thin stripes by ordinary thin-film techniques. Such sensor elements can be mass produced, e.g., by vapor deposition and etching on a large sheet of diaphragm material and cutting into chips of desired shape and size.

Abstract: A pressure sensing device having a separator diaphragm through which pressure is transmitted from a working fluid to a liquid within a first part of the device and a transducer for measuring the pressure of the liquid or the difference between the pressure of the liquid and the pressure of an external fluid. A pressure overload diaphragm comprises a dished plate which forms part of a side wall of the first part of the device and has an inner section of the plate extending inwardly of that part. The overload diaphragm is inflexible or substantially inflexible over a working range of differential pressures applied thereto but the inner section thereof moves outwardly of the first part of the device if the differential pressure exceeds a predetermined value.

Abstract: A differential pressure to electrical signal transmitter has a pair of flat barrier diaphragms and a central control diaphragm located between the barrier diaphragms. First chambers between one of the barrier diaphragms and the control diaphragm, and a first length of capillary tubing connected between the first chambers and one chamber of a remotely located sensor capsule, are filled with a first incompressible fill liquid. Second chambers between the other barrier diaphragm and the control diaphragm, and a second length of capillary tubing connected between the second chambers and another chamber of the sensor capsule, are filled with a second incompressible fill liquid. The fill liquids are made to pump up their respective flat barrier diaphragms to cause the latter to have a dome shape and hence to be free from "oil canning." A chamber on the outside of one barrier diaphragm is pressurized with a first fluid, and a chamber on the outside of the other barrier diaphragm is pressurized with a second fluid.

Abstract: A differential pressure transducer utilizing fluid-filled chambers as pressure transfer linkage to an isolated, fluid-filled aneroid sensing system. Isolation diaphragms are spread by means of internal fluid pressure fill of transfer chambers, thus providing elevated line pressure mode and pressure-biased operation. Construction offers media isolation from sensitive interior elements of the transducer. Material to come into physical contact with a pressure medium may thus be chosen for specific application. Dual, nested aneroid sensors cooperated to produce a linear displacement in response to an applied pressure differential. A cantilever beam assembly responds to the linear displacement so caused by flexing in a degree proportional to the applied pressure differential. The fluid-filled sensing system may comprise nested, aneroid capsule diaphragms, carrying a sufficient amount of incompressible fluid to support the capsule diaphragm for high line pressure use.

Abstract: A pressure sensing device comprising a ring surrounding or adapted to surround a body subjected to internal pressure; means to connect the ring physically to the body at spaced locations, the connecting means transmitting to the ring dilation and contraction movements of the body due to variation of pressure therein; said movement transmitted by the connecting means causing a portion of the ring between adjacent spaced locations to flex elastically in the manner of a bending beam, and an electrical transducer mounted upon said flexing portion of the ring, to produce electrical signals dependent on the pressure variation. One form of the device is adapted to clamp around an engine fuel line to sense fuel pressure. Another form of the device is adapted to measure engine cylinder pressure. In a further development of the invention these two forms of device are combined to feed information to engine analysing circuitry producing a visual display.

Abstract: A differential pressure to electrical signal transmitter has a pair of barrier diaphragms and one or two central control diaphragms located between the barrier diaphragms. A chamber on the outside of one barrier diaphragm is pressurized with a first fluid, and a chamber on the outside of the other barrier diaphragm is pressurized with a second fluid. First chambers between one of the barrier diaphragms and the control diaphragm, and a first length of capillary tubing connected between the first chambers and one chamber of a remotely located sensor capsule, are filled with a first incompressible fill liquid. Second chambers between the other barrier diaphragm and the control diaphragm, and a second length of capillary tubing connected between the second chambers and another chamber of the sensor capsule, are filled with a second incompressible fill liquid.