Detector arrangements for analytical apparatus

Claim 2

In an analytical instrument having an analytical section, a source of carrier gas coupled to an inlet of the analytical section, and a detector coupled to an outlet of the analytical section, an improved detector arrangement comprising: a detector cell having a plurality of members forming at least one chamber and a gas conducting passage including an inlet port and an effluent gas outlet port for conducting a carrier gas to and away from said one chamber; sensing means positioned in said one chamber and adapted for sensing the presence of sample constituents in a carrier gas; means for coupling the inlet port of said detector to said analytical section for providing a gas flow passage therebetween; and, means providing an enclosed carrier gas flow passage extending over surfaces of said cell between said one chamber outlet port and atmosphere for conducting the effluent of said one chamber around said chamber and for venting to atmosphere thereby reducing leakage between said chamber and atmosphere.

Claim 3

The apparatus of claim 1 wherein said detector cell is formed of two chambers comprising detection and reference chambers and said effluent gas comprises an effluent of said reference chamber.

Claim 4

The apparatus of claim 1 wherein said one chamber is formed by abutting surfaces of first and second cell members and said flow passage means comprises a gas passageway formed in part by adjoining surfaces of said members.

Claim 5

The apparatus of claim 2 wherein said detector cell includes a conductive passageway through each of said chambers, said sensing means includes a sensing and a reference element positioned respectively in said sensing and reference chambers, and said means providing an enclosed passage includes an enclosure for establishing a flow path for surrounding said cell with an effluent gas of said reference chamber.

Claim 6

In a thermal conductivity detector arrangement for an analytical apparatus wherein a sample under analysis is introduced thereto: a detector cell including means forming a sensing and a reference chamber and providing independent gas-conductive passageways through said chambers, each of said passageways having inlet and outlet ports; first and second electrical sensing elements positioned in said first and second chambers respectively; a body providing an enclosure for said detector cell and defining an enclosed volume between the cell and body; means for introducing a sample-carrying gas under pressure from without said second enclosure to said sensing chamber inlet port; means for introducing the carrier gas under pressure from without said second enclosure to said reference chamber inlet port; means for conveying an effluent gas from said sensing chamber outlet port to a point without said enclosure body; said reference cell outlet port positioned for exhausting an effluent of said reference chamber to said enclosed volume; and, means for venting said enclosed volume to an atmosphere without said enclosure.

Claim 7

In a thermal conductivity detector arrangement for an analytical apparatus wherein a sample under analysis is introduced thereto: a detector cell including means forming a sensing and a reference chamber and providing independent gas-conductive passageways through said chambers, each of said passageways having inlet and outlet ports; first and second electrical sensing elements positioned in said first and second chambers respectively; a body providing an enclosure for said detector cell and defining an enclosed volume between the cell and body; means for introducing a sample-carrying gas under pressure from without said second enclosure to said sensing chamber inlet port; means for introducing the carrier gas under pressure from without said second enclosure to said reference chamber inlet port; means for conveying an effluent gas from said sensing chamber outlet port to a point without said enclosure body; said reference cell outlet port positioned for exhausting an effluent of said reference chamber to said enclosed volume; and, means for venting said enclosed volume to an atmosphere without said enclosure.

Claim 8

The detector arrangement of claim 5 including a porous gas-permeable medium positioned in said enclosed volume for reducing convection noise.

Claim 9

A thermal conductivity flow through detector comprising; a first body having a surface thereof; an inlet port and a outlet port providing a vent to atmosphere formed in said body; said body having a continuous depression in said surface defining a gas flow channel communicating between said ports; means positioned in said channel for supporting a resistive temperature-sensing element; said channel including an annular portion formed about said sensing support means; and, a second body having a surface thereof positioned in abutting relationship with the surface of said first body and defining with said depression a sensing chamber and an enclosed gas passageway for conducting the effluent of said chamber around said chamber thereby reducing leakage between said chamber and atmosphere.

Claim 10

A thermal conductivity flow through detector comprising; a first body having a surface thereof; an inlet port and a outlet port providing a vent to atmosphere formed in said body; said body having a continuous depression in said surface defining a gas flow channel communicating between said ports; means positioned in said channel for supporting a resistive temperature-sensing element; said channel including an annular portion formed about said sensing support means; and, a second body having a surface thereof positioned in abutting relationship with the surface of said first body and defining with said depression a sensing chamber and an enclosed gas passageway for conducting the effluent of said chamber around said chamber thereby reducing leakage between said chamber and atmosphere.

Claim 11

The detector of claim 7 wherein said first body includes first and second inlet ports and an outlet port formed in said body and said surface of said second body defines with said depression an enclosed gas passageway and sensing and reference chambers.

Claim 12

The detector of claim 7 wherein the depression in said detector includes a plurality of annular segments formed about said sensing support means.