Pivotal Systems Corporation

Jialing Chen

Joseph R Monkowski

Tao Ding

James MacAllen Chalmers

Adam Monkowski

Sherk Chung

Paul Tran

Sophia Leonidovna Shtilman

Yi Wang

James Macallen Chalmers

Adam J Monkowski

A method and apparatus for self-calibrating control of gas flow. The gas flow rate is initially set by controlling, to a high degree of precision, the amount of opening of a flow restriction, where the design of the apparatus containing the flow restriction lends itself to achieving high precision. The gas flow rate is then measured by a pressure rate-of-drop upstream of the flow restriction, and the amount of flow restriction opening is adjusted, if need be, to obtain exactly the desired flow.

Method and apparatus for gas flow control

An apparatus to measure the transient response of a mass flow controller (MFC). The size of a variable orifice, upstream of the MFC, is controlled such that the pressure between the orifice and the MFC is held constant during the entire time that the MFC is going through its transient response. The known relationship between the size of the orifice and the flow through it allows a determination of the transient response of the MFC.

Transient measurements of mass flow controllers

Methods and apparatus utilize a rate of drop in pressure upstream of a gas flow controller (GFC) to accurately measure a rate of flow through the GFC. Measurement of the gas flow through the many gas flow controllers in production use today is enabled, without requiring any special or sophisticated pressure regulators or other special components. Various provisions ensure that none of the changes in pressure that occur during or after the measurement perturb the constant flow of gas through the GFC under test. A pressure regulator is coupled to a gas source. The GFC is positioned downstream of the pressure regulator. A pressure transducer is measuring pressure in a volume between the pressure regulator and the GFC. Techniques are provided for increasing the pressure in the volume.

Method and apparatus for in situ testing of gas flow controllers

Methods and apparatus utilize a rate of drop in pressure upstream of a gas flow controller (GFC) to accurately measure a rate of flow through the GFC. Measurement of the gas flow through the many gas flow controllers in production use today is enabled, without requiring any special or sophisticated pressure regulators or other special components. Various provisions ensure that none of the changes in pressure that occur during or after the measurement perturb the constant flow of gas through the GFC under test.

An in-situ gas flow measurement controller measures the temperature and rate of pressure drop upstream from a flow control device (FCD). The controller samples the pressure and temperature data and applies the equivalent of a decimating filter to the data to produce filtered data at a slower sampling rate. The controller derives timestamps by counting ticks from the sampling clock of the A/D converter that is sampling the pressure at regular intervals to ensure the timestamps associated with the pressure samples are accurate and do not contain jitter that is associated with software clocks. The controller additionally normalizes the temperature reading to account for power supply fluctuations, filters out noise from the pressure and temperature readings, and excludes data during periods of instability. It calculates the gas flow rate accounting for possible non-linearities in the pressure measurements, and provides the computed gas flow measurement via one of many possible interfaces.

Method and apparatus for enhancing in-situ gas flow measurement performance

Methods and apparatus utilize a rate of drop in pressure upstream of a gas flow controller (GFC) to accurately measure a rate of flow through the GFC. Measurement of the gas flow through the many gas flow controllers in production use today is enabled, without requiring any special or sophisticated pressure regulators or other special components. Various provisions ensure that none of the changes in pressure that occur during or after the measurement perturb the constant flow of gas through the GFC under test. A pressure regulator is coupled to a gas source. The GFC is positioned downstream of the pressure regulator. A pressure transducer is measuring pressure in a volume between the pressure regulator and the GFC, wherein means are provided for increasing the pressure in the volume.

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Sunnyvale, CA, United States of America

Jialing Chen