Abstract: A mass flow control apparatus and methods for calibrating and tuning the mass flow apparatus are provided. The mass flow apparatus can be calibrated by receiving a calibration input signal that provides one or more properties of a gas that is flowing through a main fluid flow path and performing one or more measurements, using one or more sensors, on the gas. The calibration includes determining a calibration parameter based on the results of the one or more measurements and the calibration input signal and adjusting a proportional valve, based on the calibration parameter, to adjust a flow rate, of the gas through the apparatus, to match a setpoint flow rate.

Abstract: A mass flow control apparatus is capable of controlling a flow rate of a fluid to a tool. Pressure of the fluid is regulated by a solenoid valve, which receives signals from a control module. Various set points may be inputted to the control module, whereby control module receives pressure sensor signals from across a flow restrictor and adjusts the solenoid valve to control the fluid flow rate to equal a set point.

Abstract: 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.

Abstract: A mass flow control apparatus comprising a proportional valve upstream of a flow measurement portion, a pressure sensing element fluidly connected to determine a fluid pressure downstream of the flow measurement portion, and a dynamically adjustable variable valve downstream of the flow measurement portion and adjacent to the pressure sensing element connection. Fluid conductance of the variable valve is adjusted according to a control scheme based upon limitations of the flow measurement portion. Integral flow verification may be enabled with additional fluid pathway elements upstream of the flow measurement portion.

Abstract: A mass flow control apparatus comprising a proportional valve upstream of a flow measurement portion, a pressure sensing element fluidly connected to determine a fluid pressure downstream of the flow measurement portion, and a dynamically adjustable variable valve downstream of the flow measurement portion and adjacent to the pressure sensing element connection. Fluid conductance of the variable valve is adjusted according to a control scheme based upon limitations of the flow measurement portion. Integral flow verification may be enabled with additional fluid pathway elements upstream of the flow measurement portion.

Abstract: A mass flow control apparatus comprising a proportional valve upstream of a flow measurement portion, a pressure sensing element fluidly connected to determine a fluid pressure downstream of the flow measurement portion, and a dynamically adjustable variable valve downstream of the flow measurement portion and adjacent to the pressure sensing element connection. Fluid conductance of the variable valve is adjusted according to a control scheme based upon limitations of the flow measurement portion. Integral flow verification may be enabled with additional fluid pathway elements upstream of the flow measurement portion.

Abstract: A mass flow control apparatus comprising a proportional valve upstream of a flow measurement portion, a pressure sensing element fluidly connected to determine a fluid pressure downstream of the flow measurement portion, and a dynamically adjustable variable valve downstream of the flow measurement portion and adjacent to the pressure sensing element connection. Fluid conductance of the variable valve is adjusted according to a control scheme based upon limitations of the flow measurement portion. Integral flow verification may be enabled with additional fluid pathway elements upstream of the flow measurement portion.

Abstract: A mass flow control apparatus comprising a proportional valve upstream of a flow measurement portion, a pressure sensing element fluidly connected to determine a fluid pressure downstream of the flow measurement portion, and a dynamically adjustable variable valve downstream of the flow measurement portion and adjacent to the pressure sensing element connection. Fluid conductance of the variable valve is adjusted according to a control scheme based upon limitations of the flow measurement portion. Integral flow verification may be enabled with additional fluid pathway elements upstream of the flow measurement portion.

Abstract: 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.

Abstract: An electronically or mechanically controlled system is devised, such that the outlet control system in a flow path delivers a desired flow rate of pre-mixed ratio and quantity of gases based on inlet and outlet pressure conditions. The desired flow rate from the system/device does not depend on type of gas/fluid being mixed such that system will always deliver a mixed gas and also do a real-time measurement of actual flow of the mixture.

Abstract: 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.

Abstract: Mass flow control methods and systems are described enabling rate of decay measurements with an orifice (or flow restrictor) located between the control volume and the outlet valve such that the outlet valve acts as the valve restricting backpressure. The system may include a main flow path and a reduced flow path that split the gas flow based on the received set point and backpressure. Measuring valve coil temperature may be used by measuring voltage and current of the valve of known resistance at room temperature and using copper coefficient of thermal resistivity delta. This temperature data may improve adjacent transducer temperature data and adjust the transducer output. Flow calculation during a long ROD pressure drop (in reduced flow rate) by making smaller flow calculation during sub section of the same, adjusting the control loop of delivered flow in real time while the ROD is still going and repeating.

Abstract: 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.

Abstract: A system comprises a flow restrictor connected to a fluid flow path and located upstream from a chamber. The flow restrictor comprises an adjustable flow restriction aperture defined by the flow path region between a first element and a second element of the flow restrictor, and a drive unit configured to adjust the relative positions of the first element, second element or both to modify the fluid flow path across the aperture. The first or second element provides a curved boundary in the aperture flow path to form a converging region, a region of closest approach and a diverging region, within the flow path. Flow rate may be determined using a reference volume upstream from the flow restrictor.

Abstract: 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.