Improvements in and relating to the control of the cooling water system of condensers, for example in a steam turbine plant

摘要

In a condenser system of the type wherein steam is condensed by direct contact with sprays of cool water, the warm water discharged from the condenser 30 (Fig. 6) is cooled by indirect heat exchange with air, the heat exchanger comprises several sectors 42 each associated with a plug valve having six ports; one pair of ports 6, 9 (Fig. 4) can be connected to the associated heat exchanger sector, another pair 4, 7 can be connected to a water storage tank 48, one port 5 of the third pair can be connected to the spray nozzles of the condenser and the other port 8 can be connected to the water circulation pumps 37. The individual heat exchange sectors are readily put into, or taken out of, service. The ports 5 are connected to the spray nozzles of the condenser via manifold 40, hydraulic turbines 33, and pipes 32. The outlets from the bottom of the condenser lead to pumps 37 which are connected to manifold 35 and the ports 8 of the valves. Pumps 37 are partly driven by turbines 33 and partly by electric motors 43. When a particular heat exchanger sector is in service, the plug is adjusted so that ports 8, 9, 6, 5, are open; and this permits water to flow from manifold 35 into the sector, and the cooled water to be discharged from the sector into manifold 40. In order to empty the sector quickly, the plug is adjusted so that ports 6, 7, 9 and 4 are open (ports 5 and 8 being closed), in order to connect the sector with pipe 44 and tank 48. To refill the sector, the plug is in the position shown in Fig. 4, whereby water flows from manifold 35 through port 8 and the internal duct 23 in the plug to port 6 and thence through pipe 46 to the sector, and water also flows past the chamfered edge 22 of the plug to port 9 and pipe 49 and thence to the sector. By-pass valve 41 permits, if opened, part of the water from the manifold to return directly to the spray nozzles of the condenser, without passing through the heat exchanger, whereby the temperature of the water sprayed into the condenser can be matched to the actual requirements of the operation. Water is supplied to the condenser from tank 48 via valve 55, when the water level in the condenser drops below a predetermined minimum.