A gases flow rate sensing system may be configured to operate in at least two different target temperature modes, based upon a measured temperature of the gases flow. In some embodiments, the gases flow sensing system may have a voltage divider containing a thermistor. The gases flow rate may be determined based upon a voltage output indicating an amount of power needed to maintain the thermistor at a target temperature as specified by the target temperature mode, and a measured temperature of the gases flow.

A gases flow rate sensing system may be configured to operate in at least two different target temperature modes, based upon a measured temperature of the gases flow. In some embodiments, the gases flow sensing system may have a voltage divider containing a thermistor. The gases flow rate may be determined based upon a voltage output indicating an amount of power needed to maintain the thermistor at a target temperature as specified by the target temperature mode, and a measured temperature of the gases flow.

A temperature monitoring system for accurate and real-time temperature monitoring may be employed at a conduit and/or a temperature control element. The conduit is configured to transport a fluid along the length of the conduit, and the conduit may comprise a variety of conduit structures having numerous cross-sections, shapes, orientation, geometry, operating conditions, operation functions, etc. The temperature control element operatively coupled to the conduit may be utilized to control the temperature of the fluid within the conduit. Typically, the temperature control element is configured to heat or cool the fluid within the conduit. The temperature monitoring system may further comprise one or more temperature sensors, such as distributed temperature sensor(s) or discrete temperature sensor(s), operatively coupled to the conduit and/or the temperature control element. The temperature sensor(s) are configured to capture temperature readings at one or more locations along the length of the conduit or the temperature control element.

A temperature monitoring system for accurate and real-time temperature monitoring may be employed at a conduit and/or a temperature control element. The conduit is configured to transport a fluid along the length of the conduit, and the conduit may comprise a variety of conduit structures having numerous cross-sections, shapes, orientation, geometry, operating conditions, operation functions, etc. The temperature control element operatively coupled to the conduit may be utilized to control the temperature of the fluid within the conduit. Typically, the temperature control element is configured to heat or cool the fluid within the conduit. The temperature monitoring system may further comprise one or more temperature sensors, such as distributed temperature sensor(s) or discrete temperature sensor(s), operatively coupled to the conduit and/or the temperature control element. The temperature sensor(s) are configured to capture temperature readings at one or more locations along the length of the conduit or the temperature control element.

We disclose herein a flow and thermal conductivity sensor comprising a semiconductor substrate comprising an etched portion, a dielectric region located on the semiconductor substrate, wherein the dielectric region comprises at least one dielectric membrane located over the etched portion of the semiconductor substrate and a heating element located within the dielectric membrane. The dielectric membrane comprises one or more discontinuities located between the heating element and an edge of the dielectric membrane.

A gas flow measuring circuit includes at least one reference resistor and at least one variable resistor that varies in accordance with the characteristics of the flow of a gas and means for determination of the difference between the reference resistor and variable resistor, with at least one current loop arrangement including first current source means coupled in series with said reference resistor and second current source means coupled in series with said variable resistor wherein both resistors are connected to ground for providing an ideally constant current through the respective resistor to produce first voltages across the reference resistor and second voltages across the variable resistor, and voltage measuring means for measuring the voltage difference between said reference resistor and said variable resistor to produce a characteristic voltage difference representative of the characteristics of the gas.

A thermal sensor device capable of maintaining measurement accuracy for a long period by suppressing plastic deformation due to thermal expansion of the heat generating resistor and reducing resistance change of the heat generating resistor, includes: a substrate having an opening; and a diaphragm having a structure in which a lower film, a heat generating resistor, and an upper film are stacked so as to bridge the opening, in which a film thickness of the lower film is larger than a film thickness of the upper film, an average thermal expansion coefficient of the lower film is larger than an average thermal expansion coefficient of the upper film, the lower film includes a plurality of films having different thermal expansion coefficients, and a film having a largest thermal expansion coefficient among the plurality of films is formed below a thickness center of the lower film.

It is an object to provide a flow rate sensor device having improved sensor responsiveness compared with the prior art. The present invention is a flow rate sensor device including a sensor element that detects a flow rate, wherein a sensor unit on which the sensor element is mounted and a drive substrate including a drive control circuit are connected through a connection portion narrower than a width of the drive substrate. Thus, a heat source in the drive substrate and a heat source in the sensor unit can be separated by the connection portion that is thin in width, and the thermal influence from the drive substrate to the sensor unit can be suppressed. Therefore, good sensor responsiveness can be maintained.

It is an object to provide a flow rate sensor device having improved sensor responsiveness compared with the prior art. The present invention is a flow rate sensor device including a sensor element that detects a flow rate, wherein a sensor unit on which the sensor element is mounted and a drive substrate including a drive control circuit are connected through a connection portion narrower than a width of the drive substrate. Thus, a heat source in the drive substrate and a heat source in the sensor unit can be separated by the connection portion that is thin in width, and the thermal influence from the drive substrate to the sensor unit can be suppressed. Therefore, good sensor responsiveness can be maintained.

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 sensor signal from the thermal mass flow sensor to produce a flow signal. A total nonlinearity characteristic function is determined based on nonlinearity effects on the flow signal and includes a first and second nonlinearity component function based on a first and second source of nonlinearity respectively. The total nonlinearity characteristic function is calibrated, and the first nonlinearity component function is adjusted responsive to changes in the first source of nonlinearity, after which the total nonlinearity characteristic function is updated. The flow signal is corrected to produce a corrected flow signal using the total nonlinearity characteristic function. A valve of the mass flow controller is controlled using the corrected flow signal and a setpoint signal.