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US 5,295,389 AGranted
Thermal conductivity detector
AssigneeYamatake-Honeywell Co., Ltd.
InventorsMitsuhiko Nagata, Shoji Kamiunten, Tatsuyuki Uchida, Misako Seita
Life of this patent
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Abstract
A thermal conductivity detector includes a thin diaphragm, a heat-generating portion, and a pair of boundary holes. The thin diaphragm is obtained by forming a space in part of a base. The heat-generating portion is formed in the diaphragm. The boundary holes are formed to surround the heat-generating portion.
Claims15
A thermal conductivity detector comprising in combination:
- a substrate base with a cavity in said substrate base;
- a thin diaphragm extending over said cavity;
- a heater element formed on a central portion of said diaphragm, said heater element exhibiting a characteristic change in its electrical impedance as a function of the thermal conductivity of a fluid flow passing over said heater element;
- a plurality of boundary holes in said thin diaphragm, said boundary holes framing said heater element at a predetermined distance from said heater element to provide thermal isolation between the heater element and said base;
- and
- said predetermined distance being sufficient that particles adhering to said boundary holes have a minimal effect on fluid flow in the vicinity of said heater element.
3 more elements
A thermal conductivity detector comprising in combination:
- a substrate base with a cavity in said substrate base;
- a thin diaphragm extending over said cavity;
- a heater element formed on a central portion of said diaphragm, said heater element exhibiting a characteristic change in its electrical impedance as a function of the thermal conductivity of a fluid flow passing over said heater element;
- a plurality of boundary holes in said thin diaphragm, said boundary holes framing said heater element at a predetermined distance from said heater element to provide thermal isolation between the heater element and said base;
- said predetermined distance being sufficient that particles adhering to said boundary holes have a minimal effect on fluid flow in the vicinity of said heater element;
- and
- a plurality of slits extending through said diaphragm in a region between said substrate base and said plurality of boundary holes.
4 more elements
Dependencies are inferred from the claim text.