An apparatus includes a casing defining a fluid flow channel, the casing including one or more diaphragms each defining a portion of the fluid flow channel, a strain gauge disposed on one of the one or more diaphragms, the strain gauge having a characteristic responsive to a pressure of fluid in the fluid flow channel, a temperature-sensitive circuit element disposed on one of the one or more diaphragms, the temperature-sensitive circuit element having a characteristic responsive to a temperature of the fluid in the fluid flow channel, and temperature compensation circuitry electrically coupled to the strain gauge and to the temperature-sensitive circuit element.

A pressure sensor includes a Wheatstone bridge circuit including a first resistor, a second resistor, a third resistor, and a fourth resistor having matching output characteristics. The pressure sensor further includes a first trim resistor in series with the Wheatstone bridge circuit, wherein the first trim resistor has output characteristics matching the output characteristics of the first resistor, the second resistor, the third resistor, and the fourth resistor of the Wheatstone bridge. The pressure sensor additionally includes a second trim resistor in parallel or a parallel loop with the Wheatstone bridge circuit, wherein the second trim resistor has output characteristics matching the output characteristics of the first resistor, the second resistor, the third resistor, and the fourth resistor of the Wheatstone bridge.

A polymeric fluid sensor includes an inlet configured to receive fluid and an outlet. A polymeric tube is fluidically interposed between the inlet and the outlet and has a first sensing location with a first sidewall thickness and a second sensing location, spaced from the first sensing location, with a second sidewall thickness. A sleeve is disposed about the polymeric tube. The first sidewall thickness is less than the second sidewall thickness and a first sensing element is disposed at the first location and a second sensing element is disposed at the second location. In another example, the first and second sidewall thicknesses are the same and a fluid restriction is disposed within the polymeric tube between the first and second sensing locations.

Intelligent temperature and pressure gauge assemblies (52) for use with vessels (24) having pressurized hazard suppression materials therein include temperature and pressure sensors (136, 138) coupled with a digital processor (72) with associated memory for storing empirical temperature and pressure data. The data includes normalized linear temperature-pressure curves consistent with static or slowly changing temperature conditions experienced by the vessels (24), as well as nonlinear temperature-pressure curves consistent with rapidly changing temperature conditions. In use, the assemblies (52) repeatedly sense the temperature and pressure conditions of the hazard suppression material and compare these sensed values with the stored values, and generate an output in conformance with the comparison. In this fashion, the assemblies (52) compensate for rapidly changing temperatures without generating false failure signals.

Certain implementations of the disclosed technology may include systems, methods, and apparatus for a sealed transducer with an adjustment port. The sealed transducer may include one or more terminals. A first terminal may include electrical connections for connecting to an input voltage source, a ground, and for providing a transducer output signal. A second terminal, for example, may include an electrical port for connecting to an external and separately sealed adjustment network. In one example implementation, the adjustment network can include one or more components configured to couple with internal circuitry of the transducer to alter a response of the transducer.

A pressure sensor includes a Wheatstone bridge circuit including a first resistor, a second resistor, a third resistor, and a fourth resistor having matching output characteristics. The pressure sensor further includes a first trim resistor in series with the Wheatstone bridge circuit, wherein the first trim resistor has output characteristics matching the output characteristics of the first resistor, the second resistor, the third resistor, and the fourth resistor of the Wheatstone bridge. The pressure sensor additionally includes a second trim resistor in parallel or a parallel loop with the Wheatstone bridge circuit, wherein the second trim resistor has output characteristics matching the output characteristics of the first resistor, the second resistor, the third resistor, and the fourth resistor of the Wheatstone bridge.

A bridge driver circuit applies a bias voltage across first and second input nodes of a resistive bridge circuit configured to measure a physical property such as pressure or movement. A sensing circuit senses a bridge current that flows through the resistive bridge circuit in response to the applied bias voltage. A temperature dependent sensitivity of the resistive bridge circuit is determined by processing the sensed bridge current. A voltage output at first and second output nodes of the resistive bridge circuit is processed to determine a value of the physical property. This processing further involves applying a temperature correction in response to the determined temperature dependent sensitivity.

The present disclosure provides a device for monitoring oil pressure in an oil cylinder of a diaphragm compressor, including a piston rod and a strain gauge circuit. The strain gauge circuit includes a strain gauge component and a bridge circuit connected, and the strain gauge component is arranged on the surface of the piston rod. A strain gauge component is noninvasively arranged on the piston rod of the diaphragm compressor to measure the load of the piston rod, such that the oil pressure can be measured indirectly, and thus the oil pressure of the diaphragm compressor can be measured nondestructively. Nondestructive and noninvasive monitoring of the diaphragm compressor is safe and reliable, and can achieve accurate monitoring of the oil pressure especially in high-pressure working conditions.

The invention relates to relates to a pressure cell configured for working according to the piezo-resistive principle and for use under high-energy radiation, particularly for use in space, i.e. to work under cosmic radiation. In order to reduce radiation drift effects during operation of the pressure cell, the pressure cell is treated with a radiation hardening procedure comprising an exposing of the cell with a radiation dose up to a saturation range of a radiation drift curve or above.

Apparatus and associated methods relate to sensing pressure and mitigating the error introduced by the thermoelectric effect. A pressure sensing device includes a pressure sensor, a temperature sensor, and an error correction device. The pressure sensor produces a voltage output proportional to a sensed pressure. The temperature sensor measures a first temperature at a first location and a second temperature at a second location to produce a temperature difference signal. The error correction device modifies the pressure output proportionally to the temperature difference signal to produce a temperature adjusted pressure output which compensates for error introduced from the temperature difference.