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 pressure transmitter with a fluid isolator that includes a sensor tube and a fill tube that have “D” shaped ends that connect together in a port internal to the transmitter. The shaped ends can be brazed into the port for sealing. Fitting both the sensor tube and the fill tube in the same port provides a low cost isolator with reduced isolator liquid volume. The fluid isolator has an isolator diaphragm with a central diaphragm region overlying a central backing plate that includes a annular groove. The annular groove avoids slow response of the isolator after an overpressure condition.

Abstract: A pressure sensor configured to sense an applied pressure, comprising a diaphragm support structure, a diaphragm coupled to the diaphragm support structure and configured to deflect in response to applied pressure, a moveable member coupled to the diaphragm and configured to move in response to deflection of the diaphragm, and an optical interference element coupled to the moveable member and configured to interfere with incident light, wherein the interference is a function of position of the moveable member.

Abstract: A sensor has an electrical interconnect grown in a cavity between first and second layers that are bonded together. Electrically conductive grain growth material is selectively deposited on at least one of two electrically conductive film interconnect regions that face one another across the cavity. The grain growth material is then grown upon predetermined conditions to form the electrical interconnect between the two interconnect regions. A sensor element deposited in the cavity is electrically coupled between the layers by the interconnect. The grain growth material can be tantalum that is heated after the layers are bonded to grow grains that interconnect the electrically conductive films.

Abstract: A pressure transmitter with first and second absolute pressure sensors receives process pressures from corresponding first and second process inlets. A transmitter circuit coupled to the first and second absolute pressure sensors generates a differential pressure type output. A third absolute pressure sensor coupled to the transmitter circuit receives atmospheric pressure from a third inlet. The transmitter circuit generates a second type of transmitter output that can be a gage or absolute pressure type. Single crystal. sapphire pressure sensors are preferred to provide enough accuracy for measuring accurately over 200:1 pressure range.

Abstract: A pressure sensor is provided for measuring a pressure difference between two fluids which does not require isolation fluid. The pressure sensor includes a diaphragm support member having an outer periphery and diaphragms coupled thereto. Movement of the diaphragms are the movement of a moveable member. The movement can be sensed to determine the applied differential pressure. The coupling member is joined to the outer periphery with a web. The web is recessed from opposed outwardly facing surfaces of the outer periphery, and first and second diaphragms disposed on opposite sides of the diaphragm support member. Each diaphragm is joined to the outer periphery and to the coupling member.

Abstract: A device and method are able to compensate for diaphragm deformation (offset) and varying dielectric constants present in a process field environment. The device can be implemented as a pressure sensor or a transmitter having a pressure sensor. The pressure sensor, filled with a dielectric fill-fluid, includes at least three capacitor plates, disposed about a diaphragm. At least two capacitor plates are placed on one side of a conductive diaphragm, and are arranged in a particular manner with respect to the diaphragm. At least one capacitor plate is placed on the other side of the diaphragm. The method compensates for both diaphragm offset and variances in the dielectric constant of the fill-fluid. An error compensated measurement of differential pressure is a function of the amount of diaphragm deflection detected at the edge region subtracted from the amount of diaphragm deflection.

Abstract: A sensor system includes a first sensor for sensing a parameter in a first sensing range and providing a first sensor signal indicative of the parameter. A second sensor senses the parameter in a second sensing range and provides a second sensor signal indicative of the parameter. The second sensing range is larger than the first sensing range and the first and second sensing ranges overlap in a transition overlap region. A sensor output device provides a sensor output signal based on the first and second sensor signals by blending components of the first and second sensor signals according to a blending function such that the sensor output signal is single valued, has no induced hysteresis and is continuously differentiable.

Abstract: A pressure transmitter has a pressure sensor coupled to an isolator diaphragm by a fill fluid such as oil. According to the invention, means are provided for measuring the position of the isolator diaphragm and comparing the measured position with an expected position to give an indication of fill fluid leakage. Non-contact arrangements such as capacitive and ultrasonic techniques are disclosed for measuring isolator diaphragm position, as well as contacting arrangements such as switches. The fill fluid loss arrangement can be incorporated into a two-wire transmitter, which transmitter can be made to send a warning signal to a control unit when fill fluid loss is detected.

Abstract: A transmitter measures pressures and has a pressure sensor and an additional pressure sensor providing additional measurement capability to the transmitter, such as an extended measurement range or measurement redundancy. Both pressure sensors share an overpressure protection device which protects them from pressures exceeding a preselected pressure limit. The pressure sensors are batch fabricated and are formed in a single piece of brittle material.

Abstract: A transmitter measures pressures and has a pressure sensor and an additional pressure sensor providing additional measurement capability to the transmitter, such as an extended measurement range or measurement redundancy. Both pressure sensors share an overpressure protection device which protects them from pressures exceeding a preselected pressure limit. The pressure sensors are batch fabricated and are formed in a single piece of brittle material.

Abstract: A pressure sensor utilizes the effect of different elastic moduli between layers or sections of different material that are bonded together to form a body, so that when the bonded material unit is subjected to a uniform hydrostatic external pressure, the differences in the elastic moduli of each of the materials will cause the materials to deflect in a predictable manner proportional to pressure. The amount of warpage or deflection of the body of material can be measured as a function of pressure. Specifically, two layers of materials, such as silicon and borosilicate glass, which have substantially different elastic moduli can be bonded across an interface surface to form an assembly, and when subjected to a substantially uniform pressure on the exterior surfaces the assembly will deflect for indicating applied pressure at relatively high pressure ranges.

Abstract: A solid state pressure sensor utilizes a brittle diaphragm made of a material such as silicon, which is mounted between base plates of glass, and which deflects in response to pressure. The base plates of glass can have recesses formed therein to receive the diaphragm and provide a full support across the diaphragm under overpressure conditions to prevent overstressing the diaphragm, or the diaphragm can have such contoured surfaces for forming overpressure stop surfaces against the facing base plate. The diaphragm has grooves defining a central portion that deflects, and whereby the grooves will form webs joining the central portion to an outer rim so that the diaphragm acts similarly to a "free edge" diaphragm in its deflection characteristics. The grooves defining the webs can have various configurations for achieving the results desired.

Abstract: A strain gauge sensor for providing an electrical output responsive to a parameter applied to a substrate. A homogenous thin film circuit is deposited on an insulating layer which is deposited on a substrate of single-crystal material. The thin film circuit includes a strain gauge responsive to strain transferred through the insulating layer from the substrate and resistance trimming networks trimmed by removal of thin film material from the trimming networks to adjust zero and gain. A diaphragm is etched in the substrate to form a pressure sensor. An optional support layer may be added to the sensor for mounting the sensor to a surface.

Abstract: A capacitive pressure sensor has a diaphragm means a portion of which is conductive which forms a first capacitor electrode. The sensor also has a reference disc means a portion of which is conductive which forms a second capacitive electrode. The diaphragm means and the reference disc means are supported in a spaced, over-lying relationship to each other by a peripheral spacer means. Responsive to pressure, the diaphragm means deflects relative to the reference disc means thus changing the capacitive spacing of the diaphragm means and the reference disc means. The diaphragm means, reference disc means and spacer means are formed from substantially the same material. The spacer means is disposed between the diaphragm means and the reference disc means adjacent their outer edges and the diaphragm means, reference disc means and spacer means are then fused together.

Abstract: A capacitance type differential pressure sensor which includes isolation diaphragms and incompressible fluid filling so that the sensing element does not have to be exposed to hostile fluids for pressure sensing and which isolation diaphragms are arranged in a manner to minimize sensitivity to acceleration forces encountered during use.