GB739694A - Improvements in devices for measuring the temperature of a gaseous flow - Google Patents

Abstract

739,694. Thermometers. GENERAL MOTORS CORPORATION. July 6, 1954 [July 23, 1953], No. 19749/54. Class 97 (3). A thermometric device for use in a stream of gas comprises a tube within which are spaced insulators supporting one or more pairs of thermocouple wires, the tube having inlet apertures near both its ends, so arranged that a substantial portion of the thermocouple wires are exposed to the gas stream and the thermocouple(s) give(s) an indication of the average temperature of two different parts of the stream. As shown in Fig. 1, a stainless steel tubular shield 18 is mounted in theannular space between walls 10, 12 of a gas turbine. A pair of thermocouple wires 30 is mounted in magnesium oxide insulators 34, 36 in stainless steel tubes 20, 22 welded in shield 18. If desired, a second pair of thermocouple wires may be mounted behind the first. Gas from two parts of the stream flowing through the annular space enters by holes 44, 46 near opposite ends of the shield 18, and after passing over the thermocouple wires leaves by a centrally placed hole 48: In an alternative arrangement, Fig. 2, the shield 54 contains magnesium oxide insulators 56, 58, 60 supporting pairs of thermocouple wires 68, 72 and dividing the shield into chambers 62, 64, 66. Each chamber has opposite inlet and outlet holes and the thermocouple junctions extend respectively into chambers 64, 66 respectively. The thermocouple wires are connected in parallel and are of different diameters so that, notwithstanding their different lengths, their resistances are equal.