Feed water pump

A feed water pump (often just called feed pump for short ) is a pump that supplies a steam boiler or steam generator with feed water that is required to generate the steam .

In steam power plants it is designed as a centrifugal pump . In larger power plants , the feed pump is preceded by a backing pump, which provides the necessary primary pressure. The feed pump is usually driven by its own, smaller steam turbine, the so-called feed pump drive turbine or also called "Spat" for short . "ESP" electric feed pumps handle start-up and shutdown . The power range of such pumps can be up to 42 MW in large power plants and is thus the largest single item of the own requirements of a steam power plant.

For safety reasons, each boiler must have at least two independently working feed devices (for large systems, one turbo feed pump and two electric feed pumps).

Piston pumps are also used for smaller steam systems (locomotives, steam cranes , smaller boiler systems) . These duplex pumps consist of two mechanically coupled pistons. The drive piston is driven by steam pressure and moves the pump piston, which pumps the feed water. The drive piston has a larger diameter than the pump piston. This allows the pump to generate a higher pressure than is supplied to it as drive pressure.

Another design previously used on steam locomotives, among other things, is the steam jet feed pump , a jet pump driven by steam .

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  Feed water pumps for the Baden biomass cogeneration plant with a pressure difference of a maximum of 90 bar and an amount of around 40 m³ / h

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  Feed water pump (main pump) power plant Niederaussem Block K a final pressure of 360 bar and an amount of 3750 m³ / h, driven by a SPAT

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  Feed water pump power plant Altbach / Deizisau HKW 2 . Structure (vL): backing pump, motor, gear control clutch, main pump

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  Redundant feed water pumps of the Steyr biomass cogeneration plant designed for 140 bar differential pressure at 40 m³ / h and with a withdrawal at 20 bar for 10 m³ / h.

Individual evidence

1. ↑ Florian Grabner: The DKW comparison process (PDF; 174 kB), page 1 ff, accessed July 29, 2012.