There is provided a fluid sensing apparatus (120) comprising a fluid flow channel (121) having a flow restriction (125), a first fluid port (132) at a first location (131) upstream of the flow restriction, a second fluid port (134) at a second location (133) downstream of the flow restriction, a fluid sensor (130) in fluid communication with the first fluid port and second fluid port, and a laminar flow element (150). The laminar flow element includes a flow stabilisation rod (151) which extends along the fluid flow channel at least from the first location to the second location to define a fluid sensing portion of the fluid flow channel between the outer wall (122) of the fluid flow channel and the outer surface (153) of the flow stabilisation rod. The flow restriction comprises a reduction in the hydraulic diameter of the fluid sensing portion of the fluid flow channel which is caused by a decrease in diameter of the fluid flow channel, or by an increase in the diameter of the flow stabilisation rod, or by both a decrease in diameter of the fluid flow channel and an increase in the diameter of the flow stabilisation rod. Also provided is a mass flow controller (100) including such a fluid sensing apparatus.

A method includes obtaining actual flow measurements generated by a flow meter, where the actual flow measurements identify a flow of material in a passageway. The method also includes generating estimated flow measurements based on process variable measurements other than the actual flow measurements. The method further includes comparing the estimated flow measurements and the actual flow measurements and determining whether a problem exists based on the comparison. The estimated flow measurements could be generated using one or more models mathematically representing how the flow of material in the passageway relates to non-flow process variables associated with the process variable measurements. The process variable measurements could be obtained from one or more sensors associated with a flow restrictor in the passageway, one or more sensors positioned within the passageway, and/or one or more sensors positioned outside the passageway.

An air flow meter capable of rapidly following a change of a pulsation state of an input signal includes: an air flow rate detection element that generates an input signal Qsen relating to an air flow rate to be measured; and a calculation unit that performs calculation to generate an output signal Qout in response to the input signal Qsen. The calculation unit includes: the output signal calculation unit that performs calculation including exponentiation of raising the power of the output signal Qout by more than one; the input signal calculation unit that performs calculation on the input signal Qsen; the subtractor that obtains the difference between the calculation results by the output signal calculation unit and the input signal calculation unit; and the integrator that integrates the difference obtained by the subtractor, and the output signal Qout is generated based on the output from the integrator.

In a substrate processing system according to an exemplary embodiment, gas supply units are configured to supply gases to chambers through first gas flow channels thereof, respectively. Chamber pressure sensors are configured to measure pressures in the chambers. A second gas flow channel is connected to the first gas flow channel of each of the gas supply units. A reference pressure sensor is configured to measure a pressure in the second gas flow channel. In a method according to an exemplary embodiment, each of the chamber pressure sensors is calibrated by using a measurement value thereof and a measurement value of the reference pressure sensor which are obtained in a state where pressures in a corresponding chamber, the first gas flow channel of a corresponding gas supply unit, and the second gas flow channel are maintained.

A differential pressure sensor is provided with an indicator assembly to represent the measured differential pressure. The sensor includes a cylindrical tube with a magnetic piston slidably disposed within. The indicator assembly is positioned adjacent to the tube and includes a first magnet having a first polarity direction and a second magnet having a second polarity direction. The magnets are provided in the indicator assembly such that the first and second polarity directions are parallel to one another. The first and second magnets are symmetrically disposed and offset from one another about a center of rotation of the indicator assembly.

Pressure regulating systems are provided. The pressure regulating systems include a pressure sensor configured to sense pressure of water flowing through a pressure regulating device; an actuator coupled to the pressure sensor; an electronics module configured to receive pressure information related sensed pressure from the actuator and process the received pressure information; and a radio module coupled to the device and configured to receive the processed sensor information from the electronics module, communicate the processed sensor information to a remote location and receive pressure adjustment information from the remote location. The received pressure adjustment information is used to adjust water pressure in the water network from the remote location.

This signal processing unit includes: a comparison signal output unit which outputs a comparison signal on a negative side that corresponds to a negative side portion, of a second amplitude-increased signal, which is on the negative side with respect to the comparison threshold TH; an averaging processing unit which outputs an average signal obtained by averaging the comparison signal; a coefficient multiplication processing unit which outputs a coefficient-multiplied signal obtained by multiplying the average signal by an adjustment coefficient set in advance; and a signal correction processing unit which outputs, as a flow rate signal, a value obtained by correcting a first amplitude-increased signal so as to be decreased by use of the coefficient-multiplied signal, wherein the comparison threshold TH is set on the basis of an output characteristic of a sensor measured in advance with respect to at least a forward flow direction of an intake air.

Fluid control systems, including mass flow control systems, mass flow ratio control systems, and mass flow and ratio control systems, as well as corresponding methods for fluid control are provided. These systems allow one shared pressure sensor to be used for multiple flow channels, and a controller which can accurately determine mass flow on the basis of fluid pressure detected by this shared pressure sensor.

An air flow meter capable of rapidly following a change of a pulsation state of an input signal includes: an air flow rate detection element that generates an input signal Qsen relating to an air flow rate to be measured; and a calculation unit that performs calculation to generate an output signal Qout in response to the input signal Qsen. The calculation unit includes: the output signal calculation unit that performs calculation including exponentiation of raising the power of the output signal Qout by more than one; the input signal calculation unit that performs calculation on the input signal Qsen; the subtractor that obtains the difference between the calculation results by the output signal calculation unit and the input signal calculation unit; and the integrator that integrates the difference obtained by the subtractor, and the output signal Qout is generated based on the output from the integrator.

There is provided an apparatus for detecting the deteriorating health of a patient receiving gas from a respiratory device. The apparatus comprises a sensor unit configured to monitor a flow rate or pressure of a gas that is flowing in a pipe that connects the respiratory device to a gas delivery device worn by the patient, and a processor configured to measure a respiratory rate of the patient based on variations in the flow rate or pressure of gas in the pipe and to implement a trend analysis of the measured respiratory rate. The processor is configured to generate a warning when it determines that there is an upward trend in the measured respiratory rate and that a magnitude of the trend exceeds a threshold.