GB733657A - Improvements in governing systems for prime movers, such as elastic fluid turbines - Google Patents

Abstract

733,657. Turbines. GENERAL ELECTRIC CO. Jan. 1, 1953 [Jan 4, 1952], No. 52/ 53. Class 110 (3). [Also in Group XXIX] A governing system for a fluid-operated prime mover, e.g. a steam turbine 2 driving a generator 6 and having a motive fluid supply valve 3 movable by a hydraulic motor 4, comprises an isochronous speed governor 12 and an exhaust pressure governor 14, the latter being operative when an external electrical source 10 is connected by contact breaker 11 to the output of generator 6 to supply a load 7, while governor 12 becomes operative if breaker 11 is opened. Governor 14 may be of the kind described in Specification 536,242, [Group XXIX], and the pressure in turbine outlet 5 is applied via line 27 to position a rod 14c which actuates pilot valve 14g controlling motor 4 through lines 20, 21. With the breaker 11 closed a solenoid 19a holds a switch 19b open, thus permitting solenoid-operated valves 16a, 17a, 18a to close drain ports 16c, 17c, 18c respectively, whereby the pressure in line 27 is operative on governor 14, and pistons 31 and 15a are held in their raised positions. Piston 15a acts through a lever 15g to. lower the seat 12c of the pilot valve 12b of governor 12, to connect lines 20, 21 and permit valve 14g to be in sole control of motor 4, follow-up being provided by connection of lever 14d to valve rod 3a. The piston 31 holds a throttle valve 28 in open position to hold a lever 13c against stop 13d and thereby render a speed corrector 13 inoperative. Follow-up is provided for valve 12b by linkage 25, 24, 23, 22 and seat 12c, the pilot valve 13f of the speed corrector being actuated by a lever 13g connected to link 24, to control a piston 13a which is connected through lever 13c to link 25 and the corrector is only effective when throttle 28 is in its minimum flow position as determined by a stop 33 on the rod of piston. 31. When switch 11 is opened the switch 19b closes, causing valves 16a, 17a, 18a to move to open position, thereby bleeding off the pressure in line 27, and permitting pistons 31, 15a to move to these lower positions. Rod 14c moves valve 14g down and piston 15a moves the seat 12c up, thereby placing the speed governor in control. The speed corrector 13 comes into operation some time after the change to speed governing, the time being preselected by adjustment of valve 37. Specifications 262,133, [Class 135], and 442,705, [Group XXIX], also are referred to.