Temperature compensation of strain gauge output
AssigneeDJ Instruments
InventorsThomas Lloyd Botker, Louis Panagotopulos
Life of this patent
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Abstract
An apparatus includes a casing defining a fluid flow channel, the casing including one or more diaphragms each defining a portion of the fluid flow channel, a strain gauge disposed on one of the one or more diaphragms, the strain gauge having a characteristic responsive to a pressure of fluid in the fluid flow channel, a temperature-sensitive circuit element disposed on one of the one or more diaphragms, the temperature-sensitive circuit element having a characteristic responsive to a temperature of the fluid in the fluid flow channel, and temperature compensation circuitry electrically coupled to the strain gauge and to the temperature-sensitive circuit element.
Claims39
An apparatus comprising:
- a casing defining a fluid flow channel, the casing comprising one or more diaphragms each defining a portion of the fluid flow channel,
- a strain gauge disposed on one of the one or more diaphragms, the strain gauge having a characteristic responsive to a pressure of fluid in the fluid flow channel,
- a temperature-sensitive circuit element disposed on one of the one or more diaphragms, the temperature-sensitive circuit element having a characteristic responsive to a temperature of the fluid in the fluid flow channel,
- wherein the strain gauge and the temperature-sensitive circuit element are both disposed on the same particular diaphragm,
- wherein the strain gauge is disposed on a flat surface of a first portion of the particular diaphragm, and
- wherein the temperature-sensitive circuit element is disposed on a flat surface of a second portion of the particular diaphragm, and
- temperature compensation circuitry electrically coupled to the strain gauge and to the temperature-sensitive circuit element.
A method comprising:
- flowing a fluid through a fluid flow channel, one or more diaphragms each defining a portion of the fluid flow channel,
- wherein a characteristic of a strain gauge disposed on a flat surface of a first portion of a particular diaphragm of the one or more diaphragms is responsive to a pressure of the fluid in the fluid flow channel, and
- wherein a characteristic of a temperature-sensitive circuit element disposed on a flat surface of a second portion of the particular diaphragm is responsive to a temperature, and
- modifying an output of the strain gauge based on the characteristic of the temperature-sensitive circuit element to compensate for temperature variation.
A method for fabricating a pressure gauge, comprising:
- defining a fluid flow path through a casing,
- thinning a portion of the casing to form a diaphragm, and
- disposing a strain gauge and a temperature-sensitive circuit element on the diaphragm, the strain gauge having a characteristic responsive to a pressure of fluid in the fluid flow path, and the temperature-sensitive circuit element having a characteristic responsive to temperature.
An apparatus comprising:
- a casing defining a fluid flow channel, the casing comprising one or more diaphragms each defining a portion of the fluid flow channel,
- a strain gauge disposed on one of the one or more diaphragms, the strain gauge having a characteristic responsive to a pressure of fluid in the fluid flow channel,
- a temperature-sensitive circuit element disposed on one of the one or more diaphragms, the temperature-sensitive circuit element having a characteristic responsive to a temperature of the fluid in the fluid flow channel,
- wherein the strain gauge is mounted on a backing, the backing providing a thermal time constant for heat transfer between the fluid and the strain gauge that is substantially equal to a thermal time constant for heat transfer between the fluid and the temperature-sensitive circuit element, and
- temperature compensation circuitry electrically coupled to the strain gauge and to the temperature-sensitive circuit element.
Dependencies are inferred from the claim text.