Thermal conductivity gauge
AssigneeMKS Instruments, Inc.
InventorsGerardo A. Brucker, Timothy C. Swinney
Life of this patent
Estimating the term…
Abstract
A thermal conductivity gauge measures gas pressure within a chamber. A sensor wire and a resistor form a circuit coupled between a power input and ground, where the sensor wire extends into the chamber and connects to the resistor via a terminal. A controller adjusts the power input, as a function of a voltage at the terminal and a voltage at the power input, to bring the sensor wire to a target temperature. Based on the adjusted power input, the controller can determine a measure of the gas pressure within the chamber.
Claims24
A thermal conductivity gauge for measuring gas pressure, comprising:
- a first resistor within a chamber coupled to a terminal;
- a second resistor in series with the first resistor and external to the chamber;
- an analog-to-digital converter (ADC) configured to determine a voltage across one of the first and second resistors;
- and
- digital circuitry configured to determine a measure of gas pressure within the chamber based on the voltage across one of the first and second resistors;
- wherein the first resistor is coupled to a grounded envelope encompassing a volume of the chamber.
A thermal conductivity gauge for measuring gas pressure, comprising:
- a first resistor within a chamber coupled to a terminal;
- a second resistor in series with the first resistor and external to the chamber;
- an analog-to-digital converter (ADC) configured to determine a voltage across one of the first and second resistors;
- digital circuitry configured to determine a measure of gas pressure within the chamber based on the voltage across one of the first and second resistors;
- and
- a controller configured to 1) determine a compensation factor based on an envelope temperature external to the chamber and 2) determine the measure of gas pressure as a function of the compensation factor.
A method of measuring gas pressure, comprising:
- applying a power input through a first resistor and a second resistor connected in series, the first resistor being coupled to a terminal within a chamber, the second resistor being external to the chamber;
- determining, via an analog-to-digital converter (ADC), a voltage across one of the first and second resistors;
- and
- determining, via digital circuitry, a measure of gas pressure within the chamber based on the voltage across one of the first and second resistors;
- wherein the first resistor is coupled to a grounded envelope encompassing a volume of the chamber.
A method of measuring gas pressure, comprising:
- applying a power input through a first resistor and a second resistor connected in series, the first resistor being coupled to a terminal within a chamber, the second resistor being external to the chamber;
- determining, via an analog-to-digital converter (ADC), a voltage across one of the first and second resistors;
- and determining, via digital circuitry, a measure of gas pressure within the chamber based on the voltage across one of the first and second resistors;
- determining a compensation factor based on an envelope temperature external to the chamber, and determining the measure of gas pressure as a function of the compensation factor.
A thermal conductivity gauge for measuring gas pressure, comprising:
- a circuit comprising a first resistor and a second resistor coupled in series, the first resistor being positioned within a chamber, the second resistor being external to the chamber;
- and
- an analog-to-digital converter (ADC) configured to determine a voltage across one of the first and second resistors;
- and
- digital circuitry configured to determine a measure of gas pressure within the chamber based on the voltage across one of the first and second resistors;
- wherein the first resistor is coupled to a grounded envelope encompassing a volume of the chamber.
Dependencies are inferred from the claim text.