Patent GB-926618-A (GB)
Title: Method of and apparatus for putting into and out of operation heat exchangers
IPC: D01G1/04
Filed: 1959-09-02
Abstract: 926,618. Gas turbine plant. SULZER FRERES S.A. Sept. 2, 1959 [Sept. 4, 1958], No. 29981/59. Class 110 (3). [Also in Groups XIII and XXIX] A method of putting into and out of operation installations for the transmission of heat having wall parts over which flows a medium whose temperature varies and which heats or cools the wall parts, comprises effecting at least one discharge of medium upstream and/or downstream of a wall part which is to be supervised to influence the flow in dependence on the temperature and/or the temperature and/or the temperature gradient, which quantity is sensed at a determined location in the medium or the wall, so that the quantity remains within the predetermined limits. The invention is applicable to the tube system of steam generators through which a cooling medium passes on extinction of the furnace or a heating medium on lighting of the furnace. The invention is also applicable to a closed cycle gas-turbine installation. In Fig. 1, pump 13 feeds water to an evaporator 11 and a superheater 12, e.g. of austenitic steel, heated at 14. In the case of a closed cycle gas turbine installation, the unit 13 would be a compressor which supplies air under pressure to the tube system 10. The supervised part 12 has its temperature gradient and temperature sensed by devices 22, 26 respectively feeding signals to a regulator 23 which controls the upstream and downstream discharges at 17, 18 by valves 19, 20 respectively in order to maintain the rate of change of temperature within predetermined limits. The regulator may receive simultaneously a signal of the temperature or the rate of flow of the medium at 32 and control a discharge valve 27a in the evaporator. The regulator may also control a steam inlet 33 and a further discharge 21. In a second embodiment, a boiler has three tube sections each having an inlet throttle and connected at their ends by four pipes to a by-pass from a feed pump to a consumer line containing three valves in parallel with each section. The first throttle and by-pass valve are adjusted manually in accordance with a chronometer and the temperature of the first section. The second throttle and valve are controlled by adjustable electric resistances on a programme drum rotated by an electric motor 59 in accordance with e.g. temperature of the furnace gases. The third throttle and valve are adjusted by a regulator controlled by a device detecting temperature gradient in the third section. This regulator comprises a bent eccentrically bored loop of tubing 72, Fig. 4, connected to the wall 71 and actuating through spring 76 on piston valve 77 controlling supply and exhaust of pressure to the end of piston valve 78 adjustably loaded at 79 for a predetermined temperature gradient and controlling through piston 82 the by-pass valve 63. When valve 63 is fully open, the piston begins to open the tube section throttle 48. In Fig. 5 temperature gradient is detected by thermocouples 95, 96 in a variable thickness wall and fed through amplifier 97 and solenoid 98 to actuate piston valve 101 and piston 102 whereby valves 19, 20, Fig. 1, are operated respectively through lever 103 and cam 105. By manually raising valve 108, piston supply valve 113 and valve 120 in series or parallel with valve 20 are closed, piston by-pass valve 114 opened and fulcrum 116 locked by pistons 110, 118, and valve 104 may be controlled at 119 by device 32, Fig. 1.