Abstract: Mass flow controllers and associated methods are provided. A mass flow controller includes a control valve configured to control flow of a fluid in a flow path and first and second flow sensors. The second flow sensor includes a pressure sensor adjacent a flow restrictor disposed in the flow path. A controller is configured to control actuation of the control valve. The controller is configured to determine a first mass flow rate based on one or more first fluid flow parameters detected by the first flow sensor, determine a second mass flow rate based on one or more second fluid flow parameters detected by the second flow sensor, calculate an orifice area of the flow restrictor based on the determined first mass flow rate, and compare a nominal orifice area of the flow restrictor with the calculated orifice area to assess a condition of the second flow sensor.

Abstract: Pulsed gas delivery is obtained with mass flow control using a thermal mass flow sensor and control valve. The controller is augmented for pressure control with a downstream pressure sensor. In separate control modes of operation, the control valve is controlled in response to the flow sensor during pulse gas delivery mode and controlled in response to the downstream pressure sensor during pressure control mode of operation.

Abstract: Mass flow control (MFC) devices capable of reporting inlet pressure and methods of reporting inlet pressure are provided. A mass flow controller (MFC) includes a chamber configured to receive a fluid, an upstream valve disposed upstream of the chamber, and a downstream control valve disposed downstream of the chamber. The MFC further includes a pressure sensor that detects fluid pressure in the chamber. The MFC further includes a controller configured to control actuation of the upstream valve. The controller is configured to toggle between two modes of reporting a measured inlet pressure. In a first mode, the controller reports a measured inlet pressure based on a reading from the pressure sensor and storing the reading to a buffer when the upstream valve is open. In a second mode, the controller reports the measured inlet pressure based on the reading stored to the buffer when the upstream valve is closed.

Abstract: Mass flow control (MFC) devices capable of reporting inlet pressure and methods of reporting inlet pressure are provided. A mass flow controller (MFC) includes a chamber configured to receive a fluid, an upstream valve disposed upstream of the chamber, and a downstream control valve disposed downstream of the chamber. The MFC further includes a pressure sensor that detects fluid pressure in the chamber. The MFC further includes a controller configured to control actuation of the upstream valve. The controller is configured to toggle between two modes of reporting a measured inlet pressure. In a first mode, the controller reports a measured inlet pressure based on a reading from the pressure sensor and storing the reading to a buffer when the upstream valve is open. In a second mode, the controller reports the measured inlet pressure based on the reading stored to the buffer when the upstream valve is closed.

Abstract: A system and method provides a more precise mole delivery amount of a process gas, for each pulse of a pulse gas delivery, by measuring a concentration of the process gas and controlling the amount of gas mixture delivered in a pulse of gas flow based on the received concentration of the process gas. The control of mole delivery amount for each pulse can be achieved by adjusting flow setpoint, pulse duration, or both.

Abstract: Mass flow controller (MFC) devices capable of self-verification and methods of providing for self-verifying mass flow control are provided. An MFC includes a chamber configured to receive a fluid, an upstream valve disposed upstream of the chamber, and a downstream control valve disposed downstream of the chamber. The MFC further includes a pressure drop element disposed downstream of the downstream control valve and first and second pressure sensors. A controller of the MFC is configured to control actuation of the downstream control valve by toggling between flow-based feedback control and pressure-based feedback control. In flow-based feedback control, a flow is monitored based on a rate of decay of pressure in the chamber as detected by the first pressure sensor upon closure of the upstream control valve. In pressure-based feedback control, a pressure upstream of the pressure drop element, as detected by the second pressure sensor, is monitored.

Abstract: Devices and methods for mass flow verification are provided. A mass flow verifier includes a chamber configured to receive a fluid, a critical flow nozzle upstream of the chamber, a chamber valve, a downstream valve, and a bypass valve. The chamber valve is configured to selectively enable fluid flow from the critical flow nozzle to the chamber. The downstream valve is configured to selectively enable fluid flow from the chamber to a downstream location. The bypass valve is configured to selectively enable fluid flow from the critical flow nozzle to a dump location. The mass flow verifier further includes a controller configured to verify flow rate of the fluid based on a rate of rise in pressure of the fluid as detected by a pressure sensor in the chamber.

Abstract: A mass flow controller and methods of providing for mass flow control are provided. A mass flow controller includes a control valve configured to control flow of a fluid in a flow path. A first flow sensor detects a first set of fluid flow parameters, and a second flow sensor detects a second set of fluid flow parameters. The first and second flow sensors are of distinct flow measurement types. The mass flow controller further includes a controller configured to determine a set of first mass flow rates based on the first set of fluid flow parameters detected by the first flow sensor and calibrate the second flow sensor based on the determined set of mass flow rates of the first mass flow sensor and the second set of fluid flow parameters.

Abstract: Pressure control methods and devices are provided. A pressure controller includes a control valve configured to control pressure of a fluid in a flow path, a flow restrictor disposed in the flow path, and distal and proximal pressure sensors. The distal pressure sensor detects fluid pressure at the flow restrictor at a location distal from the control valve, and the proximal pressure sensor detects fluid pressure at the flow restrictor at a location proximal to the control valve. The pressure controller further includes a controller configured to: 1) control actuation of the control valve based on pressure as detected by the distal pressure sensor and a pressure setpoint, and 2) determine a mass flow rate based on pressure as detected by the distal and proximal pressure sensors.

Abstract: Mass flow controller (MFC) devices capable of self-verification and methods of providing for self-verifying mass flow control are provided. An MFC includes a chamber configured to receive a fluid, an upstream valve disposed upstream of the chamber, and a downstream control valve disposed downstream of the chamber. The MFC further includes a pressure drop element disposed downstream of the downstream control valve and first and second pressure sensors. A controller of the MFC is configured to control actuation of the downstream control valve by toggling between flow-based feedback control and pressure-based feedback control. In flow-based feedback control, a flow is monitored based on a rate of decay of pressure in the chamber as detected by the first pressure sensor upon closure of the upstream control valve. In pressure-based feedback control, a pressure upstream of the pressure drop element, as detected by the second pressure sensor, is monitored.

Abstract: Mass flow controllers that can provide for improved bleeding time and can be manufactured with less complexity and cost are provided. A mass flow controller includes a body having a valve outlet bore defining a flow path and an adjustable valve configured to control flow of a gas through the flow path. A valve element includes an outlet orifice of the adjustable valve and is disposed within the bore. The mass flow controller further includes a pressure drop element disposed coaxially with the valve element within the bore. An upstream pressure sensor is configured to detect a pressure at a location in the flow path between the adjustable valve and the pressure drop element, and a controller is configured to determine a flow rate through the flow path based on pressure as detected by the upstream pressure sensor.

Abstract: A system and method for dividing a single mass flow into secondary flows of desired ratios to total flow. Each secondary flow line includes a pressure drop element, an absolute pressure sensor and a differential pressure sensor. The nonlinear relationship between flow and pressures can be transformed into a function of the absolute and differential pressures that has a linear relationship with the flow.

Abstract: Devices and methods for mass flow verification are provided. A mass flow verifier includes a chamber configured to receive a fluid, a critical flow nozzle upstream of the chamber, a chamber valve, a downstream valve, and a bypass valve. The chamber valve is configured to selectively enable fluid flow from the critical flow nozzle to the chamber. The downstream valve is configured to selectively enable fluid flow from the chamber to a downstream location. The bypass valve is configured to selectively enable fluid flow from the critical flow nozzle to a dump location. The mass flow verifier further includes a controller configured to verify flow rate of the fluid based on a rate of rise in pressure of the fluid as detected by a pressure sensor in the chamber.

Abstract: Mass flow controllers that can provide for improved bleeding time and can be manufactured with less complexity and cost are provided. A mass flow controller includes a body having a valve outlet bore defining a flow path and an adjustable valve configured to control flow of a gas through the flow path. A valve element includes an outlet orifice of the adjustable valve and is disposed within the bore. The mass flow controller further includes a pressure drop element disposed coaxially with the valve element within the bore. An upstream pressure sensor is configured to detect a pressure at a location in the flow path between the adjustable valve and the pressure drop element, and a controller is configured to determine a flow rate through the flow path based on pressure as detected by the upstream pressure sensor.

Abstract: Systems and methods for detecting a composition of a binary gas mixture are provided. Such methods and systems include, with a species-dependent mass flow meter, sensing a mass flow rate of a binary gas mixture comprising gases of differing gas correction factors and, with a species-independent pressure sensor, sensing a total pressure of the binary gas mixture. An output representative of a relative concentration of one gas of the binary gas mixture is provided. The relative concentration is determined as a function of the sensed mass flow rate and the sensed total pressure.

Abstract: A gas delivery system and associated method includes a flow channel, a control valve, a downstream pressure sensor, and a controller. The control valve controls flow of gas in the flow channel. The downstream pressure sensor, located downstream of the control valve, measures gas pressure in the flow channel. The controller has an external trigger input to receive a trigger signal applied to a shutoff valve downstream from the control valve. The controller operates in separate modes based on a state of the trigger signal. In a non-triggered mode, the controller controls pressure at the pressure sensor via the control valve in accordance with a first gain schedule. In the triggered mode, the controller controls the pressure at the pressure sensor via the control valve in accordance with a second gain schedule that is distinct from the first gain schedule.

Abstract: A system and method provides a more precise mole delivery amount of a process gas, for each pulse of a pulse gas delivery, by measuring a concentration of the process gas and controlling the amount of gas mixture delivered in a pulse of gas flow based on the received concentration of the process gas. The control of mole delivery amount for each pulse can be achieved by adjusting flow setpoint, pulse duration, or both.

Abstract: A system and method for dividing a single mass flow into secondary flows of desired ratios to total flow. Each secondary flow line includes a pressure drop element, an absolute pressure sensor and a differential pressure sensor. The nonlinear relationship between flow and pressures can be transformed into a function of the absolute and differential pressures that has a linear relationship with the flow.

Abstract: A system and method provides a more precise mole delivery amount of a process gas, for each pulse of a pulse gas delivery, by measuring a concentration of the process gas and controlling the amount of gas mixture delivered in a pulse of gas flow based on the received concentration of the process gas. The control of mole delivery amount for each pulse can be achieved by adjusting flow setpoint, pulse duration, or both.

Abstract: A fluid control system and associated method for pulse delivery of a fluid includes a shutoff valve and a mass flow controller (MFC) upstream of the shutoff valve. The MFC includes a flow channel, a control valve to control flow of fluid in the flow channel, a flow sensor to measure flow rate in the flow channel, and a controller having a valve input from the shutoff valve indicating opening of the shutoff valve. The controller is configured to respond to the valve input to control flow of fluid through the control valve to initiate and terminate a pulse of fluid from the flow channel to the shutoff valve to control a mass of fluid delivered during the pulse of fluid. The valve input can be a pressure signal, and the MFC can include a pressure sensor to sense the pressure signal.