Abstract: A micromechanical pressure sensor device and a corresponding manufacturing method. The micromechanical pressure sensor device is equipped with a sensor substrate; a diaphragm system that is anchored in the sensor substrate and that includes a first diaphragm and a second diaphragm situated spaced apart therefrom, which are circumferentially connected to one another in an edge area and enclose a reference pressure in an interior space formed in between; and a plate-shaped electrode that is suspended in the interior space and that is situated spaced apart from the first diaphragm and from the second diaphragm and forms a first capacitor with the first diaphragm and forms a second capacitor with the second diaphragm. The first diaphragm and the second diaphragm are designed in such a way that they are deformable toward one another when acted on by an external pressure.

Abstract: An improved molten solder injection head having a vacuum filter and differential gauge system is provided. In one aspect, an injection head is provided. The injection head includes: a reservoir; an injection port on a bottom of the injection head connected to the reservoir; a vacuum port adjacent to the injection port on the bottom of the injection head connected to a vacuum source; and a filter disposed between the bottom of the injection head and the vacuum source. A method for molten solder injection using the present injection head is provided.

Abstract: Electromagnetic probes for analyzing a flowing multi-phase fluid are described herein. The probes generally use a probe assembly for measuring liquid properties in a multiphase fluid flowing in a conduit, the probe assembly comprising a first member with a probe portion and a connection portion, the probe portion having a central bore with a conductor and a pressure-resistant insulator surrounding the conductor, the conductor extending from an opening at a distal end of the probe portion into the connection portion, the connection portion having a connector coupled to a distal end of the connection portion, the connection portion having a seal face with a groove extending around the probe portion; and a second member that, when assembled, is in direct contact with the first member at the distal end of the connection portion to apply compression and to retain the first member against a wall of the conduit.

Abstract: A pressure sensor assembly, which includes a support substrate, circuitry mounted to the support substrate, at least one conductor mounted to the support substrate and in electrical communication with the circuitry, and at least one vertically conductive path connected to and in electrical communication with the at least one conductor. The pressure sensor assembly also includes a diaphragm, at least one sealing glass section connected to the diaphragm and the support substrate, and at least one lateral conductive feed-through mounted to the diaphragm. At least one conductive joint is connected to the vertically conductive path and the lateral conductive feed-through, and the conductive joint provides electrical communication between the vertically conductive path and the lateral conductive feed-through.

Abstract: Systems and methods are described for sensing soot (particulate matter) in an exhaust system of a vehicle. An example system comprises a sensor housing an exhaust inlet, an exhaust outlet, and a soot filter affixed across the exhaust outlet, and a piston with the housing, affixed to a spring via a conductive surface, the spring fluidly separated from the exhaust chamber by a piston seal. The system may further comprise a detection circuit including the conductive surface of a piston and a plurality of resistive elements and a separate regeneration circuit configured to supply electric heat across the soot filter to regenerate the sensor.

Abstract: A system for measuring the superposition of a plurality of sound waves propagating within a conduit containing a fluid having a plurality of transducers positioned substantially parallel to the flow direction along the wall of the conduit. The system includes means for modeling the superposition of a plurality of sound waves as they propagate within the conduit.

Abstract: A pressure-type contact switch includes a bourdon tube which expands and contracts depending on water pressure in a discharge conduit applied by a pressure pump; a link having an end connected to a free end of the bourdon tube; a first actuating lever having an end connected to the other end of the link and rotatably installed about a first rotation axis; a first semi-circle gear formed at the other end of the first actuating lever; a first link gear engaged with the first semi-circle gear and fitted to a central rotation axis to thereby cause the central rotation axis to rotate in normal and reverse directions; a rotation member fitted to the central rotation axis; a second actuating lever which is installed to the rotation member to be rotatable about a second rotation axis; and an extension lever fitted to an end of the second actuating lever.

Abstract: The vacuum regulator includes certain components so that the vacuum regulator is able to be pre-set to a desired vacuum. The vacuum regulator has been calibrated so that a desired vacuum can be selected from a range of vacuums, whether the regulator is in the “off” position or the “on” position, and, the desired vacuum results in delivery of a corresponding level of regulated vacuum when the unit is on.

Abstract: Exemplary embodiments of the present invention provide a differential pressure transducer that comprises first and second diaphragms of different configurations, i.e., different diameters and/or thicknesses. The pressure transducer provides more versatility over prior art designs as the diaphragms can be of different configurations yet still maintain substantially similar back pressures. Therefore, the errors commonly associated with back pressures are eliminated because the back pressures from the diaphragms ultimately cancel out in the sensor's differential pressure measurement.

Abstract: A pressure sensor chip includes a sensor diaphragm that outputs a signal in accordance with a pressure differential, and first and second holding members that face, on peripheral edge portions thereof, one face and another face of a sensor diaphragm, and are in contact therewith. In the peripheral edge portion of the first holding member, in a region that faces the one face of the sensor diaphragm, a region on an outer peripheral side is a region that is bonded to the one face of the sensor diaphragm, and a region on an inner peripheral side is a region that is not bonded to the one face of the sensor diaphragm.

Abstract: A co-planar differential pressure sensor module is provided. The module includes a base having a pair of recesses. A pair of pedestals is also provided where each pedestal is disposed in a respective recess and is coupled to a respective isolation diaphragm. A differential pressure sensor has a sensing diaphragm and a pair of pressure sensing ports. Each port of the differential pressure sensor is fluidically coupled to a respective isolation diaphragm by a fill fluid. The module also includes circuitry coupled to the differential pressure sensor to measure an electrical characteristic of the sensor that varies with differential pressure. The base is constructed from a material that is suitable for submersion in seawater. A method of constructing a co-planar differential pressure sensor module is also provided. In another embodiment, a pressure sensor module is provided. The pressure sensor module includes a base having a recess. A pedestal is disposed in the recess and is coupled to an isolation diaphragm.

Abstract: A pressure sensor including: a casing fluid-tightly divided into a first and a second chamber by a deformable membrane and means for connecting the first chamber to the environment and the second chamber to a tank for an operative fluid of an electric household appliance for detecting the level thereof according to a deformation of the membrane upon the establishment of a differential pressure in the two chambers; wherein the membrane carries toward the first chamber a rigid disc operatively associated with a switch carried by the casing to either close or open the switch upon the deformation of the membrane beyond a predetermined entity.

Abstract: A vacuum sensor for sensing vacuum in a sealed enclosure is provided. The sealed enclosure includes active MEMS devices desired to be maintained in vacuum conditions. The vacuum sensor includes a motion beam anchored to an internal surface in the sealed enclosure. A driving electrode is disposed beneath the motion beam and a bias is supplied to cause the motion beam to deflect through electromotive force. A sensing electrode is also provided and detects capacitance between the sensing electrode disposed on the internal surface, and the motion beam. Capacitance changes as the gap between the motion beam and the sensing electrode changes. The amount of deflection is determined by the vacuum level in the sealed enclosure. The vacuum level in the sealed enclosure is thereby sensed by the sensing electrode.

Abstract: Fabry-Perot and Bragg grating optical measuring principles are combined with a torsional stress sensing mechanism that converts torque applied in one fluid environment to force exerted in a second environment to measure extreme environmental parameters such as pressure in a petroleum producing borehole.

Abstract: A drug delivery device (10) includes a pressurized reservoir (14) in communication with a flow path to an outlet (12). The flow path includes two normally-closed valves (16, 18) and a flow restriction (18). A pressure measurement arrangement (22) measures a differential fluid pressure between two points (24, 26) along the flow path which span at least part of the flow restriction (18), one of the points being between the valves (16, 18). A controller (28) selectively opens the valves (16, 18) to deliver a defined quantity of the liquid medicament to the outlet (12).

Abstract: Apparatus for measuring a differential pressure of a fluid flowing through a fluid line includes a nozzle having a nozzle interior wall defining a nozzle chamber. The nozzle interior wall tapers at a constant rate of area reduction to generate a laminar fluid flow. A differential pipe is coupled to the nozzle and fluidly communicates with a downstream portion of the fluid line. The differential pipe has a pipe interior wall defining a differential chamber fluidly communicating with the nozzle chamber. A first pressure port is formed in the nozzle and fluidly communicates with the nozzle chamber to obtain a first gauge pressure of the fluid, and a second pressure port is formed in the differential pipe and fluidly communicates with the differential chamber to obtain a second gauge pressure of the fluid.

Abstract: A transducer comprising a filter assembly that measures low amplitude, dynamic pressure perturbations superimposed on top of a high static pressure through the implementation of a low-pass mechanical filter assembly. The filter assembly may comprise a dual lumen reference tube and a removable filter subassembly further comprising a porous metal filter and narrow diameter tube. The transducer, which may be capable of operating at ultra-high temperatures and in harsh environments, may comprise of a static piezoresistive pressure sensor, which measures the large pressures on the order of 200 psi and greater, and an ultrasensitive, dynamic piezoresistive pressure sensor which may capture small, high frequency pressure oscillations on the order of a few psi. The filter assembly may transmit static pressure to the back of the dynamic pressure sensor to cancel out the static pressure present at the front of the sensor while removing dynamic pressure.

Abstract: There is disclosed an internally switched multiple range transducer. The transducer employs a plurality of individual pressure sensors or Wheatstone bridges fabricated from semiconductor materials and utilizing piezoresistors. Each sensor is designed to accommodate accurately a given pressure range, therefore, each sensor is selected to provide an output when an applied pressure is within its accommodated range. As soon as the pressure exceeds the range, then another sensor is employed to produce an output. Each of the sensors, or each separate transducer, is coupled to a switch or other device to enable the selection of one of the plurality of sensors to operate within its given pressure range when the applied pressure is in that range. In this manner one obtains pressure measurements with a high degree of accuracy across a relatively large pressure range.

Abstract: The present disclosure relates to pressure sensors. In one illustrative embodiment, the pressure sensor may include a pressure sensor assembly having pressure ports on opposite sides of the pressure sensor assembly. The pressure sensor may include a protective housing including a first housing member and a second housing member defining a cavity for securely housing the pressure sensor assembly. The protective housing may include a first port coupled to one of the pressure ports of the pressure sensor assembly and a second port coupled to the other pressure port of the pressure sensor assembly. In some cases, the protective housing may include one or more aligning features, one or more positioning features, and a boss, which can include two or more bumps, on each side of the cavity around the pressure ports.

Abstract: A pressure sensor including a sensor chip; a differential pressure diaphragm provided in the center portion of the sensor chip; a first differential pressure gauge formed along a radial direction relative to the center of the differential pressure diaphragm, provided on a first edge of the differential pressure diaphragm; a second differential pressure gauge formed along a circumferential direction, which is perpendicular to the radial direction, provided in the vicinity of the first differential pressure gauge on the first edge of the differential pressure diaphragm; and a static pressure diaphragm disposed between an edge portion of the sensor chip and one of the edges, other than the first edge, of the differential pressure diaphragm, provided to the outside of the differential pressure diaphragm.

Abstract: A pressure transducer arrangement and method of operation is provided. The pressure transducer and methods of operation reduce error in determining an offset value by eliminating error relating to fluid flow through the transducer arrangement when the offset value is determined. In a particular embodiment, the apparatus and method includes a lockout valve that prevents fluid flow between first and second fluid pressure sources when the offset value is determined.

Abstract: A pressure sensor for detecting a pressure of a first object to be measured; a pressure sensor for detecting a pressure of a second object to be measured; a temperature sensor for detecting the temperature of the pressure sensor and the pressure sensor; a first correcting portion for executing a correction that eliminates a fluctuation portion, due to a change in temperature, from the detection signal of the pressure sensor, and for outputting the signal, after the correction, as a measurement signal for the first object to be measured; and a second correcting portion for executing a correction that eliminates a fluctuation portion, due to a change in temperature, from the detection signal of the pressure sensor, and for outputting the signal, after the correction, as a measurement signal for the second object to be measured; wherein the temperature sensor is integrated with the pressure sensor and the pressure sensor so as to be in a state of mutual contact.

Abstract: A pressure difference measuring cell for registering pressure difference between a first pressure and a second pressure, comprises: an elastic measuring arrangement having at least one measuring membrane, or diaphragm, that comprises silicon; a platform, which is pressure-tightly connected with the elastic measuring arrangement; a first hydraulic path for transferring a first pressure onto a first surface section of the elastic measuring arrangement; and a second hydraulic path for transferring a second pressure onto a second surface section of the elastic measuring arrangement. The first pressure opposes the second pressure, and the elastic deflection of the measuring arrangement is a measure for the difference between the first and the second pressure, wherein the pressure difference measuring cell has additionally at least one hydraulic throttle, characterized in that the at least one hydraulic throttle comprises porous silicon.

Abstract: A process transmitter for measuring a process variable in an industrial process comprises a gauge pressure sensor, an excitation source and transmitter circuitry. The gauge pressure sensor measures a pressure difference between a process fluid and a reference volume, and generates a pressure sensor signal representing the pressure difference. The excitation source generates a pressure pulse within the reference volume to influence generation of the pressure sensor signal. The transmitter circuitry is connected to the gauge pressure sensor to provide an output related to a change in the pressure sensor signal due to the pressure pulse.

Abstract: A method and apparatus are described for fabricating an exposed differential pressure sensor (30) which protects interior electrical components (37) formed on a topside surface of a differential pressure sensor transducer die (31) from corrosive particles using a molding compound (39), but which vents both sides of a piezoresistive transducer sensor diaphragm (33) through a first vent hole (42) formed in an exposed die flag (36) and a second vent hole (38) formed in an exposed cap structure (33), enabling the sensor diaphragm (33) to sense differential pressure variations directly or indirectly through a protective gel.

Abstract: A pressure sensor includes a hydraulic path filled with a pressure transfer liquid and a pressure transducer having a pressure sensitive deformation body. The hydraulic path includes a channel which extends from a pressure input opening at least to the deformation body, wherein the pressure input opening is spaced a separation distance from the deformation body, and wherein pressure on the deformation body deviates from pressure at the pressure input opening by the difference of the hydrostatic pressure of the pressure transfer liquid between the pressure input opening and the deformation body.

Abstract: A micromechanical capacitive pressure sensor has a layered structure, which includes at least one deflectable carrier element for at least one deflectable measuring electrode in a first layer plane and at least one stationary carrier structure for at least one counter electrode in a second layer plane parallel to the first layer plane. The carrier structure is suspended in a closed cavity of the layered structure between two diaphragms, which are oriented essentially perpendicularly to the layer planes and delimit the cavity on two opposite sides. At least one pressure connection aperture is provided, via which at least one of the two diaphragms may be subjected to a pressure being measured. The carrier element is connected to the two diaphragms in such a way that diaphragm deformations cause a parallel shift of the measuring electrode relative to the counter electrode.

Abstract: A diaphragm section has a mesh-like beam section which partitions the diaphragm section into a plurality of rectangular regions, and a thin film section formed in the region partitioned by the beam section, and the thickness of the thin film section is less than that of the beam section.

Abstract: A MEMS differential pressure sensing element is provided by two separate silicon dies attached to opposite sides of a silicon or glass spacer, the sides of which are recessed and the recesses formed therein at least partially evacuated. The dies are attached to the spacer using silicon-to-silicon bonding provided in part by silicon oxide layers if a silicon spacer is used. The dies can be also attached to the spacer using anodic bonding if a glass spacer is used. Conductive vias extend through the layers and provide electrical connections between Wheatstone bridge circuits formed from piezoresistors in the silicon dies.

Abstract: The invention concerns a pressure sensor (5), particularly for a depth gauge (1), capable of having a high level of precision, owing to sufficient elastic deflection amplitude of the diaphragm (or membrane), while avoiding any risk of plastic deformation. The diaphragm (12) is formed by a flat metal disc. The peripheral region (13) thereof is neither welded nor inset, but it is pre-stressed against a stop strip (25) with a closed, preferably circular contour, and can pivot on the stop strip (25) when the diaphragm bends under the effect of fluid pressure in the pressure chamber (10). The pre-stressing may be achieved via a sealing gasket (21) located opposite the stop strip (25). Between said strip and a central aperture (15), a concave stop surface (20) limits the deflection of the diaphragm (12) and prevents any plastic deformation in the event of excessive pressure. Manufacture of the diaphragm is simple, with a high level of reproducibility, assembly is easy and the seal quality is high.

Abstract: A differential pressure gauge includes a housing, a leaf spring having a magnetic steel, a measuring diaphragm, a helix, a dial, a range adjusting device and a diaphragm cover. The measuring diaphragm is connected with the leaf spring by connectors. The range adjusting device includes an adjusting spring provided at a lower end of the measuring diaphragm, a balance spring provided at an upper end of the measuring diaphragm, an adjusting screw and a slider which are provided at a lower end of the adjusting spring. The adjusting end of the adjusting screw is provided outside of the housing. The adjusting spring can be compressed by the upper and lower displacement of the slider driven by the adjusting screw, thus affecting the rigidity of the system to change the range of the differential pressure gauge. The differential pressure gauge facilitates adjusting the range and has the accurate measurement.

Abstract: A process variable transmitter for measuring a pressure of a process fluid includes a process coupling having a first port configured to couple to a first process pressure and a second port configured to couple to a second process pressure. A differential pressure sensor is coupled to the first and second ports and provides an output related to a differential pressure between the first pressure and the second pressure. First and second pressure sensors couple to the respective first and second ports and provide outputs related to the first and second pressures. Transmitter circuitry is configured to provide a transmitter output based upon the output from the differential pressure sensor and/or the first and/or second pressure sensors. Additional functionality is provided by the transmitter using the sensed first and/or second pressures.

Abstract: The present disclosure relates to pressure sensors. In one illustrative embodiment, the pressure sensor may include a pressure sensor assembly having pressure ports on opposite sides of the pressure sensor assembly. The pressure sensor may include a protective housing including a first housing member and a second housing member defining a cavity for securely housing the pressure sensor assembly. The protective housing may include a first port coupled to one of the pressure ports of the pressure sensor assembly and a second port coupled to the other pressure port of the pressure sensor assembly. In some cases, the protective housing may include one or more aligning features, one or more positioning features, and a boss, which can include two or more bumps, on each side of the cavity around the pressure ports.

Abstract: A filter assembly for use with a static-dynamic piezoresistive pressure transducer that measures low amplitude, dynamic pressure perturbations superimposed on top of a high static pressure through the implementation of a low-pass mechanical filter assembly is disclosed. The filter assembly may comprise a dual lumen reference tube and a removable filter subassembly further comprising a porous metal filter and narrow diameter tube. The transducer, which may be capable of operating at ultra-high temperatures and in harsh environments, may comprise of a static piezoresistive pressure sensor, which measures the large pressures on the order of 200 psi and greater, and an ultrasensitive, dynamic piezoresistive pressure sensor which may capture small, high frequency pressure oscillations on the order of a few psi or less.

Abstract: A pressure sensor according to the present invention comprises: a differential pressure diaphragm, which is provided to a center part of a sensor chip; a differential pressure gauge, which is provided to a perimeter edge part of the differential pressure diaphragm and is formed in radial directions; a differential pressure gauge, which is disposed at a position at which it opposes the differential pressure gauge and, together with the first differential pressure gauge, sandwiches the differential pressure diaphragm and is formed in perimeter directions, which are perpendicular to the radial directions; a differential pressure gauge, which is provided in the vicinity of the differential pressure gauge and is provided in the perimeter directions; a differential pressure gauge, which is disposed at a position at which it opposes the differential pressure gauge and, together with the differential pressure gauge, sandwiches the differential pressure diaphragm and is formed in the radial directions; a static pressu

Abstract: There is disclosed an internally switched multiple range transducer. The transducer employs a plurality of individual pressure sensors or Wheatstone bridges fabricated from semiconductor materials and utilizing piezoresistors. Each sensor is designed to accommodate accurately a given pressure range, therefore, each sensor is selected to provide an output when an applied pressure is within its accommodated range. As soon as the pressure exceeds the range, then another sensor is employed to produce an output. Each of the sensors, or each separate transducer, is coupled to a switch or other device to enable the selection of one of the plurality of sensors to operate within its given pressure range when the applied pressure is in that range. In this manner one obtains pressure measurements with a high degree of accuracy across a relatively large pressure range.

Abstract: A sensor design, respectively a micromechanical sensor structure for capacitive relative-pressure measurement, that will allow very small pressure differentials to be reliably recorded at high absolute pressures even in harsh, particle-laden measuring environments. For that purpose, the micromechanical sensor element includes a deflectable diaphragm structure which is provided with at least one deflectable electrode, and a fixed support structure for at least one fixed counter-electrode which is located opposite the deflectable electrode. The diaphragm structure includes two mutually parallel configured diaphragms that are joined rigidly to one another via at least one connecting crosspiece, so that each application of force to one of the two diaphragms is directly transmitted to the respective other diaphragm.

Abstract: A dual pressure sensor using a reduced number of parts to simplify its structure and having increased ease of assembly and improved air tightness. The dual pressure sensor has an airtight container, two pressure sensor units received in the airtight container so as to be in intimate contact with each other and a substrate. The pressure sensor units has two bases, two pressure sensing diaphragm chips, and an output correction circuit. The pressure sensing diaphragm chips are secured to the bases, respectively. The bases are constructed respectively from base bodies having communication paths formed inside them and also respectively from pressure introduction sections integral with and projecting from the base bodies. The pressure introduction sections respectively project outward from insertion holes formed in the airtight container.

Abstract: A pressure sensor is disclosed wherein pressure induced changes in birefringent properties of an optical sensing element are read out by transmission of at least one light beam. The pressure sensor can include at least one single-material transparent body which is subjected to at least two different pressures (p1, p2) in at least two different regions via at least two pressure chambers. The transparent body can transmit by a parallel or minimally divergent light beam without total reflection in the body such that the pressure-induced birefringence and a corresponding differential phase shift between linear polarisation components of the light beam depends on a difference of the different pressures (p1, p2).

Abstract: In order to reduce hysteresis and other noise components included in the output signal characteristic of a differential pressure sensor, an elastic reaction member which operates together with a diaphragm provided in a chamber of the differential pressure sensor includes a contact portion which contacts the diaphragm, and a plurality of springs which are arranged symmetrically about the contact portion. Each of the springs is a plate shaped or linear shaped spring which is bent into the form of a letter C, U, J, or V, and has one of its ends fixed to a wall which defines the chamber, while its other end is connected to the contact portion. When the contact portion shifts together with the diaphragm, the deformations of the plurality of springs are mutually balanced, so that rotation and horizontal deviation of the contact portion with respect to the diaphragm is suppressed.

Abstract: An apparatus for measuring the differential pressure of fluid in filter. The apparatus comprises a housing defining a pressure chamber. A differential pressure gauge divides the pressure chamber into first and second fluid chambers. The differential pressure gauge is arranged to measure a differential pressure between fluid in the first chamber and fluid in the second chamber. The differential pressure gauge has a variable output.

Abstract: A pressure transducer for a pressure sensor (2) for determining at least one pressure (pa, pb) in a process media (3a, 3b) has a housing (4) with a separating diaphragm (5a, 5b), at least one first pressure-sensing element (6a, 6b), a contact media (7a, 7b), at least one first connection element (8a, 8b) and at least one first seal (9a, 9b). The separating diaphragm (5a, 5b) separates the process media (3a, 3b) from the contact media (7a, 7b), the contact media (7a, 7b) conveys the pressure (pa, pb) of the process media (3a, 3b) determined by the separating diaphragm (5a, 5b) to the first pressure-sensing element (6a, 6b). The first seal (9a, 9b) houses the first connection element (8a, 8b) and the housing (4), the separating diaphragm (5a, 5b) and the first seal (9a, 9b) form a first pressure chamber (10a, 10b).

Abstract: A process pulsation diagnostic system comprises a primary element, a sensor and a processor. The primary element generates a differential pressure along a fluid flow. The sensor samples the differential pressure. The processor generates a pulsation diagnostic based on a standard deviation of the differential pressure, such that the pulsation diagnostic is indicative of a degree of process pulsation in the fluid flow.

Abstract: The disclosure relates to a differential pressure transducer unit comprising an over-load protection system which is used to measure low differential pressure in liquids and gases under high static pressure load which can be connected to flanges on the working pressure lines. The differential pressure transducer unit consists of a planar multi-layered arrangement comprising layers which are conductive, insulating and which are insulated from each other, whereby the insulating and conductive layers comprises recesses which at least partially cover each other, wherein the measuring mechanism and the measuring value processing means are accommodated. At least one of the layers is a functional component of the over-load protection system.

Abstract: A method and apparatus for measuring the size and distribution of particles within a multiphase fluid flowing within a pipe is provided, wherein the apparatus includes at least one metering device for determining at least one of the mixture density of the fluid, the flow rate of the fluid and the dispersion of the fluid, wherein the at least one metering device generates meter data responsive to at least one of the mixture density of the fluid, the flow rate of the fluid and the dispersion of the fluid and a processing device communicated with the at least one metering device, wherein the processing device receives and processes the meter data to generate fluid information responsive to the size and distribution of the particles within the fluid.

Abstract: A differential liquid pressure sensor (10) has an upper housing (12) that mounts a connector portion (12a) and receives in a recess a sense element module (14). The sense element module is a body in which a generally U-shaped oil filled passageway (14h) is formed with openings at opposite ends provided on respective first and second diaphragm mounting surfaces. A fluid pressure sense element, such as a piezoresistive sense element (15) is disposed in one of the passageway openings and flexible metal diaphragms (14a, 14b) are mounted on the respective diaphragm mounting surfaces of the module facing a common direction. A lower housing (18) having first and second port connections for the respective diaphragms is disposed on the lower surface of the module.

Abstract: The object of this invention is to provide a method of maintaining a multi-tubular reactor which can ensure the uniformity of states of reaction in the reaction tubes in the multi-tubular reactor. This invention is a method of maintaining a multi-tubular reactor in good condition by selecting a part of reaction tubes in a multi-tubular reactor at random, measuring a differential pressure occurring in each reaction tube when passing gas therethrough, separating any reaction tube showing an abnormal differential pressure as compared with the average of differential pressures in reaction tubes packed with an fresh catalyst of the same kind, giving adequate treatment to the separated reaction tube and returning it into the reactor with any other selected reaction tube falling within a normal range.

Abstract: A method and an apparatus for servicing a coolant system is disclosed. Using the apparatus, a user may fill the coolant system with coolant. The user may also measure a current pressure of the coolant system. The apparatus then compares the current pressure with a predetermined pressure associated with an ambient temperature to determine a coolant charge status. The apparatus alerts a user to the coolant charge status of the coolant system using an indicating device.

Abstract: Reliability and accuracy in a pressure measurement transmitter are provided by employing a plurality of absolute or gauge pressure sensors operating in conjunction with a differential pressure sensor. A method is also provided to perform diagnostics based upon the readings of the three pressure sensors. Further, should one of the three pressure sensors fail, a reasonable estimate of process pressure being measured by the failed sensor can be generated based upon the remaining two sensors.

Abstract: A fiber optic differential pressure sensor. In a described embodiment, a differential pressure sensor system for use in a subterranean well includes a fluid property sensing housing having a flow passage formed therethrough. A differential pressure sensor has an optical fiber extending in a wall having a first side and a second side, each of the first and second sides being exposed to pressure in the flow passage.