Combustible concentration analyzer

• US 4,141,955 A
• Filed: 10/25/1977
• Issued: 02/27/1979
• Est. Priority Date: 10/25/1977
• Status: Expired due to Term

• Current Assignee: Joseph O. Obiaya
• Original Assignee: Joseph O. Obiaya
• Inventors: Obiaya, Joseph O.
• Primary Examiner(s): Wolk, Morris O.
• Assistant Examiner(s): Turk, Arnold
• Application Number:
  US05/845,050
• Time in Patent Office: 490 Days
• Field of Search: 23/254 E, 23/232 E, 23/255 E, 136/224, 136/225, 136/226, 136/227
• US Class Current: 422/95
• CPC Class Codes: G01N 25/32 using thermoelectric elements
• CPC Class Codes: G01N 33/0016 by regulating a physical variable, e.g. pressure, temperature

Abstract

Combustible element analyzer for determining the combustible element concentration of a sample gas. The sample is routed through an inlet conduit, mixed with a source of air, heated to an elevated temperature and analyzed by the combustible element analyzer. The analyzer includes a number of series connected thermocouples forming a thermopile. Exothermic reactions induced in the sample by catalyst elements create temperature variations along the thermopile. These variations cause a voltage difference along the thermopile whose value can be correlated to the combustible element concentration within the sample. Means are included for maintaining uniform sample flow past the analyzer and for maintaining analyzer calibration should the flow rate vary.

Claims

1. A combustible element analyzer comprising:

(a) a substrate base formed from an electrically insulating material;

said base including two configured opposite surfaces;

(b) a plurality of series connected thermocouples attached to a first surface of said base, said thermocouples forming a thermopile matrix;

(c) a plurality of catalyst material structures connected at spaced locations along said matrix to induce exothermic oxidation reactions at alternate junctions of said thermocouples among the components of a fluid sample thereby producing voltage differences along said matrix;

said voltage differences adding in series to produce a total voltage signal larger than electrical noise within the thermopile, thereby enhancing the signal to noise ratio;

(d) means for electrically connecting the matrix to a monitor which will correlate matrix voltage to combustible gas concentration; and

(e) a means for raising the ambient temperature of said matrix to a uniform value, said means attached to a second surface of said base material.

2. The combustible element analyzer of claim 1 wherein the catalyst element is platinum, and the matrix thermocouples are formed from chromel and alumel.