Carbon monoxide detection apparatus

Claim 2

A carbon monoxide detector comprising; (a) at least one forward biased solid-state measuring diode connected to provide a first output signal; (b) an equal number of forward biased solid-state reference diodes connected to provide a second output signal; (c) a deposit of an oxide of a noble metal in heat conducting relationship to the measuring diode, said deposit serving as an catalyst for carbon monoxide oxidation; and (d) electrical means for generating an output signal that varies in accordance with the difference between the first and second output signals.

Claim 3

A carbon monoxide detector as set forth in claim 1 in which the noble metal is platinum.

Claim 4

A carbon monoxide detector as set forth in claim 1 in which said deposit is a coating applied to the body of each measuring diode.

Claim 5

A carbon monoxide detector as set forth in claim 1 in which the measuring diodes are mounted in a metal casing and in which said deposit is applied to the casing.

Claim 6

A carbon monoxide detector as set forth in claim 1 in which the operating temperature of the diodes is in the range of 160° C. to 300° C.

Claim 7

A carbon monoxide detector as set forth in claim 2 in which the operating temperature of the diodes is approximately 180° C.

Claim 8

A carbon monoxide detector as set forth in claim 1, 2, 5 or 6 in which the detector is supplied with a sample gas that contains enough oxygen to prevent any carbon monoxide therein from reducing the noble metal oxide to the noble metal.

Claim 9

A carbon monoxide detector as set forth in claim 1 in which the deposit is held in place by a layer of a thermally conducting epoxy.

Claim 10

A carbon monoxide detector comprising: (a) a plurality of series-connected measuring thermocouple junctions coated with an oxide of a noble metal; (b) an equal number of series-connected reference thermocouple junctions not coated with an oxide of a noble metal; (c) electrical means for comparing the total voltage at the measuring thermocouple junctions with the total voltage at the reference thermocouple junctions.

Claim 11

A carbon monoxide detector comprising: (a) a plurality of series-connected measuring thermocouple junctions coated with an oxide of a noble metal; (b) an equal number of series-connected reference thermocouple junctions not coated with an oxide of a noble metal; (c) electrical means for comparing the total voltage at the measuring thermocouple junctions with the total voltage at the reference thermocouple junctions.

Claim 12

A carbon monoxide detector as set forth in claim 9 in which the noble metal is platinum.

Claim 13

A carbon monoxide detector as set forth in claim 9 in which the operating temperature of the thermocouple junctions is in the range of 160° C. to 300° C.

Claim 14

A carbon monoxide detector as set forth in claim 10 in which the operating temperature of the thermocouple junctions is approximately 180° C.

Claim 15

A carbon monoxide detector as set forth in claim 9, 11 or 12 in which the detector is supplied with a sample gas that contains enough oxygen to prevent any carbon monoxide therein from reducing the noble metal oxide to the noble metal.

Claim 16

A carbon monoxide detector as set forth in claim 9 in which the oxide is held in place by a layer of a thermally conducting epoxy.

Claim 17

A carbon monoxide detector comprising: (a) at least one temperature responsive measuring element connected to provide a first signal; (b) an equal number of temperature responsive reference elements connected to provide a second signal; (c) casing means for mounting the measuring elements and the reference elements; (d) a temperature maintenance chamber surrounding the casing means, the chamber having an inlet and an outlet; (e) means for regulating the temperature inside the temperature maintenance chamber; (f) a deposit of a noble metal oxide on said casing means in heat conducting relationship to the measuring elements and not in heat conducting relationship to the reference elements; (g) said inlet and outlet being arranged to direct a flow of a sample gas across the deposit; and (h) means for generating an output signal that varies in accordance with the difference between said first and second signals.

Claim 18

A carbon monoxide detector comprising: (a) at least one temperature responsive measuring element connected to provide a first signal; (b) an equal number of temperature responsive reference elements connected to provide a second signal; (c) casing means for mounting the measuring elements and the reference elements; (d) a temperature maintenance chamber surrounding the casing means, the chamber having an inlet and an outlet; (e) means for regulating the temperature inside the temperature maintenance chamber; (f) a deposit of a noble metal oxide on said casing means in heat conducting relationship to the measuring elements and not in heat conducting relationship to the reference elements; (g) said inlet and outlet being arranged to direct a flow of a sample gas across the deposit; and (h) means for generating an output signal that varies in accordance with the difference between said first and second signals.

Claim 19

A carbon monoxide detector as set forth in claim 15 in which the temperature inside the temperature maintenance chamber is between 160° C. and 300° C.

Claim 20

A carbon monoxide detector as set forth in claim 15 in which the noble metal is platinum and in which the temperature inside the temperature maintenance chamber is approximately 180° C.

Claim 21

A carbon monoxide detector as set forth in claim 15, 16 or 17 in which the detector is provided with a sample gas that contains enough oxygen to prevent the reduction of the noble metal oxide to the noble metal.

Claim 22

A carbon monoxide detector as set forth in claim 15 in which the noble metal is platinum.