Abstract: A mass flow controller includes a thermal mass flow sensor in combination with a pressure sensor to provide a mass flow controller that is relatively insensitive to fluctuations in input pressure. The pressure sensor and thermal sensor respectively provide signals to an electronic controller indicating the measured inlet flow rate and the pressure within the dead volume. The electronic controller employs the measured pressure to compensate the measured inlet flow rate and to thereby produce a compensated measure of the outlet flow rate, which may be used to operate a mass flow controller control valve.

Abstract: A mass flow controller includes an electronic controller for which a plurality of closed loop control codes sets may be uploaded. In a dual processor embodiment, one processor may upload a plurality of codes sets for another, with the selection of codes sets determined by the uploading processor either autonomously or through user interaction.

Abstract: A mass flow controller includes a thermal mass flow sensor in combination with a pressure sensor to provide a mass flow controller that is relatively insensitive to fluctuations in input pressure. The pressure sensor and thermal sensor respectively provide signals to an electronic controller indicating the measured inlet flow rate and the pressure within the dead volume. The electronic controller employs the measured pressure to compensate the measured inlet flow rate and to thereby produce a compensated measure of the outlet flow rate, which may be used to operate a mass flow controller control valve.

Abstract: A mass flow controller includes a network interface port and interface software that provide direct access to the mass flow controller. The mass flow controller also includes diagnostic software that permits a technician to execute diagnostics through the network interface port.

Abstract: A system for dividing a single mass flow, including an inlet adapted to receive the single mass flow and at least two flow lines connected to the inlet. Each flow line includes a flow meter and a valve. The system also includes a controller programmed to receive a desired ratio of flow through a user interface, receive signals indicative of measured flow from the flow meters, calculate an actual ratio of flow through the flow lines based upon the measured flows, and compare the actual ratio to the desired ratio. The controller is also programmed to calculate the desired flow through at least one of the flow lines if the actual ratio is unequal to the desired ratio, and provide a signal indicative of the desired flow to at least one of the valves.

Abstract: A thermal mass flow controller includes a sensor assembly, a valve assembly, and mass flow controller housing. A thermal ground limits the conductive thermal path between the mass flow controller housing and the sensor assembly and, due to the limited cross-section of the thermal ground, substantially eliminates externally imposed thermal gradients within the sensor assembly. The controller also includes a thermally dissipative element that conducts thermal energy along a path from the valve assembly away from the sensor assembly.

Abstract: A system for dividing a single mass flow, including an inlet adapted to receive the single mass flow and at least two flow lines connected to the inlet. Each flow line includes a flow meter and a valve. The system also includes a controller programmed to receive a desired ratio of flow through a user interface, receive signals indicative of measured flow from the flow meters, calculate an actual ratio of flow through the flow lines based upon the measured flows, and compare the actual ratio to the desired ratio. The controller is also programmed to calculate the desired flow through at least one of the flow lines if the actual ratio is unequal to the desired ratio, and provide a signal indicative of the desired flow to at least one of the valves.

Abstract: A mass flow controller includes a thermal mass flow sensor in combination with a pressure sensor to provide a mass flow controller that is relatively insensitive to fluctuations in input pressure. The pressure sensor and thermal sensor respectively provide signals to an electronic controller indicating the measured inlet flow rate and the pressure within the dead volume. The electronic controller employs the measured pressure to compensate the measured inlet flow rate and to thereby produce a compensated measure of the outlet flow rate, which may be used to operate a mass flow controller control valve.

Abstract: A thermal mass flow controller includes a sensor assembly and mass flow controller housing. A thermal ground limits the conductive thermal path between the mass flow controller housing and the sensor assembly and, due to the limited cross-section of the thermal ground, substantially eliminates externally imposed thermal gradients within the sensor assembly.

Abstract: A thermal mass flow controller includes a sensor assembly, a valve assembly, and a mass flow controller housing. A thermally conductive element conducts heat from the valve assembly away from the sensor assembly, thereby reducing uncontrolled contributions of heat to the sensor assembly.

Abstract: A mass flow controller includes a thermal mass flow sensor in combination with a pressure sensor to provide a mass flow controller that is relatively insensitive to fluctuations in input pressure. The pressure sensor and thermal sensor respectively provide signals to an electronic controller indicating the measured inlet flow rate and the pressure within the dead volume. The electronic controller employs the measured pressure to compensate the measured inlet flow rate and to thereby produce a compensated measure of the outlet flow rate, which may be used to operate a mass flow controller control valve.

Abstract: A mass flow controller includes an electronic controller that provides a web server that allows access to the web server through such interworking networks as the Internet.

Abstract: A mass flow controller includes a mass flow sensor and a calibrator configured to perform a self-calibration on the mass flow controller. The calibrator generates flow measurements that are used as “standards” and flow measurements from the mass flow sensor are correlated to flow measurements from the calibrator.

Abstract: A mass flow controller includes an interface and control for executing diagnostics while the mass flow controller's electronic controller executes closed loop process control.

Abstract: A mass flow controller includes an electronic controller that monitors a mass flow signal from a mass flow sensor and produces a closed loop control signal for operation of an outlet valve. The electronic controller includes two processors, one of which may be a deterministic and the other a non-deterministic processor.

Abstract: A mass flow controller includes a pressure sensor that senses pressure within the mass flow controller and displays the pressure. The pressure display may be local, mounted directly to the mass flow controller, or it may be connected through a link to the mass flow controller for remote display.

Abstract: A mass flow sensor calibrator employs a variable-flow fluid source, a receptacle of known volume, and a pressure differentiator. The variable-flow fluid source supplies gas at varying rates to the mass flow sensor being calibrated and at proportional rates to a receptacle of known volume. A pressure differentiator computes the time derivative of gas flow into the receptacle of known volume and, from that, the actual flow into the receptacle. Given the actual flow, the proportionate flow into the mass flow sensor may be determined and the flow signal from the mass flow sensor correlated to the actual flow.

Abstract: A mass flow controller includes a network interface port and interface software that provide direct access to the mass flow controller. The mass flow controller also includes diagnostic software that permits a technician to execute diagnostics through the network interface port.

Abstract: A mass flow controller includes an electronic controller for which a plurality of closed loop control codes sets may be uploaded. In a dual processor embodiment, one processor may upload a plurality of codes sets for another, with the selection of codes sets determined by the uploading processor either autonomously or through user interaction.

Abstract: A system for dividing a single mass flow, including an inlet adapted to receive the single mass flow and at least two flow lines connected to the inlet. Each flow line includes a flow meter and a valve. The system also includes a controller programmed to receive a desired ratio of flow through a user interface, receive signals indicative of measured flow from the flow meters, calculate an actual ratio of flow through the flow lines based upon the measured flows, and compare the actual ratio to the desired ratio. The controller is also programmed to calculate the desired flow through at least one of the flow lines if the actual ratio is unequal to the desired ratio, and provide a signal indicative of the desired flow to at least one of the valves.