We disclose herein a flow sensor comprising: a first substrate comprising an etched portion, a dielectric region located on a first side of the first substrate, wherein the dielectric region comprises at least one dielectric membrane located over the etched portion of the first substrate, a sensing element located on or within the dielectric membrane, and a second substrate adjoining a second side of the first substrate. The first side of the first substrate and the second side of the first substrate are opposite sides. The first substrate and the second substrate cooperate to form a sensing channel through the flow sensor.

Mass flow controllers and methods for controlling mass flow controllers are disclosed. A method includes providing a gas through a thermal mass flow sensor of the mass flow controller and processing a flow sensor signal from the thermal mass flow sensor of the mass flow controller to produce a measured flow signal. The measured flow signal is corrected to produce a corrected flow signal by gradually applying non-linearity correction to the measured flow signal when a flow rate of the gas changes. A valve of the mass flow controller is controlled using the corrected flow signal and a setpoint signal.

A thermal flow-rate sensor includes: a first temperature sensor that detects the temperature at a specified location of the outer-wall surface of a pipe; a heat-transfer element that is arranged on the outer-wall surface of the pipe in a state separated from the first temperature sensor, and that exchanges heat with a measurement medium by heating or cooling the outer-wall surface of the pipe; a second temperature sensor that detects the temperature of a portion of the outer-wall surface of the pipe that is heated or cooled by the heat-transfer element; and a control unit that performs specified processing. A heat-flux sensor is arranged between the heat-transfer element and the outer-wall surface of the pipe and directly detects heat flux between the heat-transfer element and the pipe; and the control unit detects the flow rate of the measurement medium based on the temperature that is directly detected by the first temperature sensor, the temperature that is detected by the second temperature sensor, and the heat flux that is detected by the heat-flux sensor.

A method and apparatus for making a flow determination with respect to a flow through a fluid conduit is described. The apparatus comprises a first temperature sensor arranged to generate a temperature signal indicative of the temperature of the outer surface of the fluid conduit, a second temperature sensor arranged to generate a temperature signal indicative of the ambient temperature outside of the fluid conduit; and a processor arranged to make the flow determination. The flow determination is made by determining the first and second temperatures at a first time; predicting a predicted first temperature at a second time; determining the first temperature at the second time; and comparing the predicted first temperature with the determined first temperature at the second time.

The disclosed embodiments include a method, apparatus, and computer program product for improving the accuracy of a rate of decay measurement for real time correction in a mass flow controller or mass flow meter by using a thermal model to minimize thermally induced error in the rate of decay measurement.

A device for measuring the rate of flow of a fluid comprising. The device includes a heating element, a housing, and a detector. The heating element is located in an interior of the housing, the housing defining a first thermal path from the heating element to a first region of an exterior of the housing and a second thermal path from the heating element to a second region of the exterior of the housing. The detector is configured to detect a property associated with transfer of heat from the heating element to the exterior of the housing. The first thermal path has a first thermal conductivity and the second thermal path has a second thermal conductivity. The first thermal conductivity is greater than the second thermal conductivity. The first region of the exterior of the housing is smaller than the second region of the exterior of the housing.

An electric measurement method and apparatus for detecting a mass by an electric capacity (permittivity) or a material's dielectric constant, or alternatively, electric inductance (permeability). The mass may be any phase or combination of phases. The mass may be stationary or flowing. It may comprise discrete particles such as grain, or manufactured products such as ball bearings or threaded fasteners, etc. The mass may be a flow element in a rotameter or similar flow measurement device. The sensor comprises a volume which may be completely full or only partially full of the material. The material may be discrete components or a continuum. Sensor signals may be received by existing planter monitoring systems. In some embodiments the flow sensors are positioned external to the application port. In some embodiments sensors may be utilized which are responsive to the refractive index variation of specific chemicals.

An electronic device manufacturing system includes a mass flow controller (MFC) that has a thermal flow sensor. The thermal flow sensor may measure a mass flow rate and may include a sensor tube having an inner surface coated with a material to form an inner barrier layer. The inner barrier layer may prevent or substantially reduce the likelihood of a corrosive reaction from occurring on the inner surface, which may prevent or reduce the likelihood of the MFC drifting beyond the MFC's mass flow rate accuracy specifications. This may improve the repeatability of flow detection by the MFC. Methods of measuring and controlling a mass flow rate in an electronic device manufacturing system are also provided, as are other aspects.

A thermal, flow measuring device for determining and/or monitoring a mass flow of a measured medium, comprising a sensor element (1, 11, 21) having a measuring tube (2, 12, 22) with a tube wall (7, 17, 27) and with at least a first and a second temperature sensor element, which are especially embodied as resistance thermometers (3, 13, 23, 33), wherein at least one of the temperature sensor elements is heatable, wherein the measuring tube (2, 12, 22) has a longitudinal axis (A) and a tube contour (8, 18, 28) with a first tube cross section in the end regions of the measuring tube (2, 12, 22), wherein the measuring tube (2, 12, 22) includes a narrowing having a second tube cross section, which differs in form and/or area from the first tube cross section, wherein the narrowing is divided into at least two segments (6, 16, 26), wherein at least one of the segments (6, 16, 26) is angled relative to the longitudinal axis (A) of the measuring tube (2, 12, 22) by an angle () of at least 5 and wherein, in each case, one of the temperature sensor elements is arranged in a respective one of the two segments (6, 16, 26) externally on the tube wall (7, 17, 27) of the measuring tube (2, 12, 22) and is located in thermal contact with the measured medium.

The present invention is intended to improve the responsiveness while increasing a flow rate, and is an orifice having a valve seat surface, the orifice includes: a vertical channel that opens to valve seat surface and a facing surface that faces the valve seat surface; and a horizontal channel that opens to an outer circumferential surface between the valve seat surface and the facing surface, and that intersects with the vertical channel. The vertical channel is split into a plurality of channel branches from an intersection with the horizontal channel, with a space therebetween, on a side of the facing surface.