Abstract: This disclosure relates to mass flow verification systems for and methods of measuring and verifying the mass flow through a mass flow delivery/measurement device such as a mass flow controller. A mass flow verification system includes a preset volume, a temperature sensor, and a pressure sensor. The measured verified flow determined by the mass flow verification system can be adjusted to compensate for errors resulting from a dead volume within the mass flow measurement device.

Abstract: A system performs mass flow delivery of a fluid, and also performs mass flow verification of the fluid. The system includes an inlet valve that controls flow of the fluid into a chamber, an outlet valve that controls flow of the fluid out of the chamber, a pressure transducer that measures the pressure of the fluid within the chamber, a temperature sensor that measures the temperature of the fluid within the chamber, and a controller. The controller is configured to control opening and closing of the inlet and outlet valves, using the measurements of the pressure and the temperature change within the chamber, so as to verify, when in a first mode, a measurement of the flow rate of the fluid by a device, and so as to deliver, when in a second mode, a desired amount of the fluid from the chamber into a processing facility.

Abstract: This disclosure relates to mass flow verification systems for and methods of measuring and verifying the mass flow through a mass flow measurement device such as a mass flow controller. A mass flow verification system comprises a preset volume, a temperature sensor, and a pressure sensor. The measured verified flow determined by the mass flow verification system can be adjusted to compensate for errors resulting from a dead volume within the mass flow measurement device.

Abstract: A high accuracy mass flow verifier (HAMFV) which provides high measurement accuracy over a wide flow verification range with low inlet pressures is disclosed for verifying flow measurement by a fluid delivery device. The HAMFV includes a chamber defining a plurality N of inlets with upstream valves, an outlet with a downstream valve, a pressure sensor and a temperature sensor configured to measure the pressure and the temperature of the fluid within the chamber, respectively. A plurality N of critical flow nozzles is located adjacent to the corresponding upstream valve. The HAMFV further includes a controller configured to activate one of the plurality N of critical flow nozzles based on the desired flow verification range and the fluid type by opening the corresponding upstream valve and closing all other upstream valves. At least two of the plurality N of critical flow nozzles have different cross-sectional areas.

Abstract: A system performs mass flow delivery of a fluid, and also performs mass flow verification of the fluid. The system includes an inlet valve that controls flow of the fluid into a chamber, an outlet valve that controls flow of the fluid out of the chamber, a pressure transducer that measures the pressure of the fluid within the chamber, a temperature sensor that measures the temperature of the fluid within the chamber, and a controller. The controller is configured to control opening and closing of the inlet and outlet valves, using the measurements of the pressure and the temperature change within the chamber, so as to verify, when in a first mode, a measurement of the flow rate of the fluid by a device, and so as to deliver, when in a second mode, a desired amount of the fluid from the chamber into a processing facility.

Abstract: A high accuracy mass flow verifier (HAMFV) which provides high measurement accuracy over a wide flow verification range with low inlet pressures is disclosed for verifying flow measurement by a fluid delivery device. The HAMFV includes a chamber defining a plurality N of inlets with upstream valves, an outlet with a downstream valve, a pressure sensor and a temperature sensor configured to measure the pressure and the temperature of the fluid within the chamber, respectively. A plurality N of critical flow nozzles is located adjacent to the corresponding upstream valve. The HAMFV further includes a controller configured to activate one of the plurality N of critical flow nozzles based on the desired flow verification range and the fluid type by opening the corresponding upstream valve and closing all other upstream valves. At least two of the plurality N of critical flow nozzles have different cross-sectional areas.

Abstract: A flow verifier for verifying measurement by a fluid delivery device under test (DUT) includes a chamber configured to receive a flow of the fluid from the DUT, at least one temperature sensor to provide gas temperature in the chamber, at least one pressure transducer to provide gas pressure in the chamber, and a critical flow nozzle located upstream of the chamber along a flow path of the fluid from the DUT to the chamber. The critical flow nozzle and the flow verification process are configured to maintain the flow rate of the fluid through the nozzle at the critical flow condition such that the flow rate through the nozzle is substantially constant and substantially insensitive to any variation in pressure within the chamber downstream of the nozzle.

Abstract: The multiple antisymmetric optimal (MAO) control algorithm is disclosed for a gas delivery system including a flow ratio controller for dividing a single mass flow into multiple flow lines. In the MAO control algorithm, each flow line is provided with a flow sensor and a valve actively controlled by a SISO feedback controller combined with a linear saturator to achieve the targeted flow ratio set point. For optimal control performance, these SISO controller and linear saturators are substantial identical. It is proved that each valve control command is multiple antisymmetric to the summation of all other valve control commands. Therefore, the MAO control algorithm guarantees that there exists at least one valve at the allowable maximum open position at any moment, which achieves the optimal solution in terms of the maximum total valve conductance for a given set of flow ratio set points.

Abstract: A thermal mass flow controller for controlling flow rate of a fluid includes a conduit configured to receive the fluid, a pressure sensor that measures the pressure of the fluid as the fluid flows within the conduit, a temperature sensor that measures the ambient temperature of the fluid, and a thermal sensor that generates an output representative of the flow rate of the fluid. The thermal mass flow controller further includes a control system configured to monitor the output from the thermal sensor, the pressure measured by the pressure sensor, and the ambient temperature measured by the temperature sensor, to regulate flow of the fluid within the conduit so as to compensate for a shift in the thermal sensor output caused by thermal siphoning.

Abstract: A thermal mass flow meter for measuring flow rate of a fluid includes a conduit that is configured to receive the fluid and that defines a primary flow path between an inlet and an outlet of the conduit. The conduit is bound at least in part by a sensor receiving surface. A thermal sensor tube has a thermal sensing portion that is mounted relative to the sensor receiving surface in a direction substantially perpendicular to both the primary flow path and the sensor receiving surface. When the thermal mass flow meter is mounted in a vertical direction so that fluid within the conduit flows in the vertical direction along the primary flow path, fluid within the sensor tube flows in a horizontal direction so as to substantially prevent thermal siphoning when the sensor tube is heated.

Abstract: A flow verifier for verifying measurement by a fluid delivery device under test (DUT) includes a chamber configured to receive a flow of the fluid from the DUT, at least one temperature sensor to provide gas temperature in the chamber, at least one pressure transducer to provide gas pressure in the chamber, and a critical flow nozzle located upstream of the chamber along a flow path of the fluid from the DUT to the chamber. The critical flow nozzle and the flow verification process are configured to maintain the flow rate of the fluid through the nozzle at the critical flow condition such that the flow rate through the nozzle is substantially constant and substantially insensitive to any variation in pressure within the chamber downstream of the nozzle.

Abstract: The antisymmetric optimal control algorithm is disclosed for a gas delivery system including a flow ratio controller for dividing a single mass flow into at least two flow lines. Each flow line includes a flow meter and a valve. Both valves of the flow ratio controller are controlled through a ratio feedback loop by the antisymmetric optimal controller which includes a single input single output SISO controller, an inverter and two linear saturators. The output of the SISO controller is split and modified before being applied to the two valves. The two valve control commands are virtually antisymmetric to the maximum allowable valve conductance position.

Abstract: A system and method for in-situ verification and calibration of flow control devices includes a first network physical layer connecting the flow control devices to a flow verification device. A controller of the flow verification device is programmed to communicate with each of the flow control devices through the first network physical layer, receive gas specific information and a transfer function from each of the flow control devices, and verify the flow of each flow control device. The controller of the flow verification device is further programmed to communicate with each of the flow control devices through the first network physical layer and, if necessary, calibrate the flow control devices. The verification and calibration of the flow control devices is preferably carried out based upon a single command provided through a tool controller connected to a second network physical layer connected to the flow control devices.

Abstract: A system and method for in-situ verification and calibration of flow control devices includes a first network physical layer connecting the flow control devices to a flow verification device. A controller of the flow verification device is programmed to communicate with each of the flow control devices through the first network physical layer, receive gas specific information and a transfer function from each of the flow control devices, and verify the flow of each flow control device. The controller of the flow verification device is further programmed to communicate with each of the flow control devices through the first network physical layer and, if necessary, calibrate the flow control devices. The verification and calibration of the flow control devices is preferably carried out based upon a single command provided through a tool controller connected to a second network physical layer connected to the flow control devices.