GB870666A - A device for the automatic starting of emergency feed-water pumps - Google Patents

Abstract

870,666. Fluid-pressure servomotor control systems. PRVNI BRNENSKA STROJIRNA, ZAVODY KLEMENTA GOTTWALDA, NARODNI PODNIK. Oct. 29, 1958 [Oct. 29, 1957 (2); Nov. 5, 1957], No. 34680/58. Class 135. [Also in Groups XXVI and XXVIII] A device for automatic starting of emergency feed-water pumps 1 with steam-turbine drive 2 on a drop in water pressure in the common feed line 28 by means of an auxiliary oil pump 29 driven by a steam turbine, in which the steam supply to the latter is controlled by the pressure in the suction line 34 of the pump 1. A pressure reduction in line 28, due to failure of the main electrically driven feed pumps, moves shuttle valve 32 via a lever and diaphragm 30 to pass pump suction line pressure through pipe 33 to diaphragm 38 to open steam supply valve 36 for turbine 29 driving the auxiliary oil pump, the speed of the turbine being controlled by pump outlet pressure actuating steam valve 41 through pipe 42 and a diaphragm. Oil pressure from pump 29 passes piston valve 20, which may be moved by hand at 24 or by a centrifugal trip device 23 on overspeeding of turbine 2 for connecting the pressure line 19 to sump, and moves piston 16 as far as line 26 to open a small steam supply valve 13 for low-speed warming up of turbine 2. Oil pressure via line 19, restriction 7 and line 6 moves piston valve 11 so that oil pressure via line 42 actuates piston 8 and opens turbine regulating valve 9. Pressure in line 26 leads to sump via piston valve 25, but the latter is moved downwards by pressure in 19 so that after a delay the drain to sump is closed and pressure in 26 lifts a piston valve 22 to release pressure in line 6 whereby piston valve 11 is lowered and piston 8 raised to close turbine valve 9 for equalizing pressure on both sides of main steam supply valve 14. With pressure built up in line 26, piston 16 opens valve 14 to supply full steam pressure and opens line 27 whereby pressure in line 19 acts on the top of valve 22 to stop the venting of line 6, whereupon pressure in line 6 raises valve 11 to re-open turbine regulating valve 9 for full-speed driving of pump 1. Pump 1 drives an oil pump 43 to replace pump 29 and its outlet pressure in line 42 closes valve 41 to cut out turbine and pump 29. The speed of turbine 2 is controlled by governor 3 actuating a leak-off valve with respect to a moving seat on the end of the hollow stem of piston 4 which actuates a further piston and piston valve 5 controlling a leak-off from line 6 leading to valve 11 controlling valve 9.