A self-correcting pressure-based mass flow control apparatus includes outlet pressure sensing to enable correction for non-ideal operating conditions. Further the mass flow control apparatus having a fluid pathway, a shutoff valve in the fluid pathway, a reference volume in the fluid pathway, a first pressure measuring sensor in fluid communication with the reference volume, a first temperature measuring sensor providing a temperature signal indicative of the fluid temperature within the reference volume, a proportional valve in the fluid pathway, and a second pressure measuring sensor in fluid communication with the fluid pathway.

Provided is a device for measuring a gas concentration, including: a preheating module configured to preheat and rectify an input to-be-measured gas to output a first stage gas; a differential pressure conversion module connected to the preheating module, wherein the differential pressure conversion module is configured to allow the first stage gas flowing through to generate a differential pressure change value; and a processing module configured to acquire a volume concentration of the to-be-measured gas according to the differential pressure change value; wherein the differential pressure conversion module comprises a capillary laminar flow unit having a plurality of capillaries, and flow channels of the plurality of capillaries become a main channel of a gas flow, so as to form a laminar flow structure. A method for measuring a gas concentration is further provided, including measuring a concentration of a to-be-measured gas using the above-mentioned device for measuring a gas concentration.

Provided is a device for measuring a gas concentration, including: a preheating module configured to preheat and rectify an input to-be-measured gas to output a first stage gas; a differential pressure conversion module connected to the preheating module, wherein the differential pressure conversion module is configured to allow the first stage gas flowing through to generate a differential pressure change value; and a processing module configured to acquire a volume concentration of the to-be-measured gas according to the differential pressure change value; wherein the differential pressure conversion module comprises a capillary laminar flow unit having a plurality of capillaries, and flow channels of the plurality of capillaries become a main channel of a gas flow, so as to form a laminar flow structure. A method for measuring a gas concentration is further provided, including measuring a concentration of a to-be-measured gas using the above-mentioned device for measuring a gas concentration.

To provide a flow rate control valve that can improve responsiveness of flow rate control of a pressure differential type of a flow rate control device. The flow rate control valve is so configured to comprise a pair of valve members each of which has a seat surface being in contact with each other, to provide an internal flow channel that opens toward the seat surfaces and that passes through the inside of at least one of the valve members, and to control a flow rate of a fluid flowing out through the internal flow channel to the outside by adjusting a separation distance between the seat surfaces. And a restricted flow channel is formed in the internal flow channel so that a differential pressure is generated between an upstream side and a downstream side of the restricted flow channel.

A flowmeter for measuring a fluid flow rate in a pipe includes a base made of a flexible material; a bridge made of a rigid material, wherein the bridge is attached to the base to form a microchannel; and a pressure sensor formed within the base. The microchannel has a height H between 100 and 400 μm.

A reference volume for use with pressure change flow rate measurement apparatus has an internal structure comprising elements with cross section and length comparable to the cross section and length of adjacent interstitial fluid regions. The reference volume may have one or more heat conduction elements exterior to and in good thermal contact with a corrosion resistant material that defines the internal fluid holding region.

A reference volume for use with pressure change flow rate measurement apparatus has an internal structure comprising elements with cross section and length comparable to the cross section and length of adjacent interstitial fluid regions. The reference volume may have one or more heat conduction elements exterior to and in good thermal contact with a corrosion resistant material that defines the internal fluid holding region.

A flow rate ratio control device is provided with a main flow path, a plurality of branch flow paths that branch off from a terminus of the main flow path, a plurality of fluid control devices that are provided respectively on each branch flow path, and that are each equipped with a valve and a pressure-based flow rate sensor that is disposed downstream of the valve, and an operation setting unit that establishes settings such that, based on the target flow rate ratio, any one fluid control device from among the plurality of fluid control devices is made to operate in a flow velocity control mode in which the flow velocity of a fluid is controlled upstream of each valve, and the remaining fluid control devices are made to operate in a flow rate control mode in which the flow rate is controlled based on the target flow rates.

A flow rate ratio control device is provided with a main flow path, a plurality of branch flow paths that branch off from a terminus of the main flow path, a plurality of fluid control devices that are provided respectively on each branch flow path, and that are each equipped with a valve and a pressure-based flow rate sensor that is disposed downstream of the valve, and an operation setting unit that establishes settings such that, based on the target flow rate ratio, any one fluid control device from among the plurality of fluid control devices is made to operate in a flow velocity control mode in which the flow velocity of a fluid is controlled upstream of each valve, and the remaining fluid control devices are made to operate in a flow rate control mode in which the flow rate is controlled based on the target flow rates.

A fluid delivery system includes N first valves. Inlets of the N first valves are fluidly connected to N gas sources, respectively, where N is an integer greater than zero. N mass flow controllers include a microelectromechanical (MEMS) Coriolis flow sensor having an inlet in fluid communication with an outlet of a corresponding one of the N first valves. A second valve has an inlet in fluid communication with an outlet of the MEMS Coriolis flow sensor and an outlet supplying fluid to treat a substrate arranged in a processing chamber. A controller in communication with the MEMS Coriolis flow sensor is configured to determine at least one of a mass flow rate and a density of fluid flowing through the MEMS Coriolis flow sensor.