Patent GB-832604-A (GB)
Title: Improvements in or relating to thermocouple harness
IPC: F01D17/08
Filed: 1956-01-27
Abstract: 832,604. Thermocouple mountings. FENWAL Inc. Jan. 27, 1956 [Oct. 17, 1955], No. 2805/56. Class 40 (1). [Also in Group XXXVI] A harness section adapted to be coupled to a like section to form a thermocouple harness comprises at least one deformable segment 6 and means 5 fitted to the said segment or each said segment for supporting a thermocouple 8 and connecting it in circuit with an output from the harness. As shown, the harness comprises two thermocouple mounting sections 2, 3 which are coupled together by means of connector boxes 7 and which are connected to a utilization device such as a recording or indicating instrument by means of an output section 4. Each section 2, 3 inaddition to the connector boxes 7 has a number of the means 5 which, as shown, are terminal boxes, and these are joined together and to the connector boxes 7 by the segments 6. Another terminal box 5b is used for the connection of the output section 4. The segments 6 each consist of two insulating wires, each wire being mounted in a channel formed in a metal plate. Each terminal box 5 comprises a pair of interfitting base and cover parts 18 and 19. The parts 18, 19 are joined together by three hollow rivets 20 the central one of which provides a passage through which a shield tube 9 of the thermocouple 8 is passed and the others of which provide passages for bolt fasteners 38 by which the terminal box is connected to the thermocouple and also to a bracket 36 forming the means for detachably mounting the terminal box in a wall opening 37a about a gas stream. Each terminal box has two contact buttons 21 mounted in oversize openings in its cover 19 and insulated from the cover by mica washers 24. The wires of the segments 6 are joined to these buttons so that when they are in contact with corresponding contact buttons 14 on the thermocouples, the thermocouples are connected in parallel. Each thermocouple has a pair of wires 10 extending through the shield tube 9 and insulated from it by magnesium oxide. The wires 10 extend beyond the inner end of the shield tube and are joined together to form the hot junction 10a. They also extend beyond the other end of the shield tube 9 and are joined to the contact buttons 14 which are mounted in but insulated from a baseplate 13 connected to the shield tube 9. The base-plate 13 has apertures through which the fasteners 38 can pass to secure the thermocouple to the terminal box 5. The passage in the central rivet 20 in the terminal box for the shield tube 9 is off-set from the passages for the fastenings 38 so that the thermocouple can only be connected to the terminal box in one position. The plate 13 is provided with a cap 17 which is welded in place. The connector boxes 7 each comprise base and cover parts 28, 29 which are welded together after the wires of a segment 6 have been connected to contact buttons 31. These contact buttons are identical with the contact button in the terminal boxes 5 and mounted in the same way. The base and cover parts are joined by a hollow spacing rivet 30 through which a bolt fastener 34 can be passed to join one connector box 7 to another connector box 7. Each connector box 7 is provided with a plate 35, Fig. 1, which bears on the other box when two boxes are connected together, to correctly position them. The output section 4 comprises a segment which is similar to the segment 6 connecting the terminal boxes 5 and this is fitted with a terminal box 5a at one end which engages the terminal box 5b in the section 2. The terminal boxes 5a and 5b are similar to the terminal boxes 5 but differ in shape and have no opening for the thermocouple. The wires at the other end of the section 4 are fitted with clips for connection to terminal posts or the like. In a modification the terminal boxes 5 are connected by pairs of segments 6. The two sections on this modification can be joined at one end only. In a further modification a plurality of sections are connected in parallel.