Injector

Steam feed pumps are driven with steam jet pumps, which are used as feed pumps for steam boilers of steam power plants and steam locomotives. Because of their simple structure and with an availability of the required amount of steam, the steam jet pump, in the event that other pumps are failed, is used as a reserve on ships.

Principle

The taken out of the boiler steam at high pressure is passed into a pipe to the nozzle, where it reaches a high exit velocity. This is sucked by a shunt pipe supply water to the steam velocity, and accelerated. The velocity of the water is converted to an opposite line by deceleration in static pressure which is higher than the pressure in the boiler. The water is thus fed into the boiler. This operation is only possible because the hot vapor cools and condenses. Thus, the previously invested evaporation energy is released again and contributes to the acceleration.

Use in the steam locomotive

These are often known also under the name " injector " type of dining establishment is divided into non-absorbent and absorbent pumps, depending on whether the water will flow from the pump or the Tender must be sucked from her. The former pumps (type Friedmann ) are built a little easier, but are in the steam locomotive of the risk of freezing exposed, they must lie deeper than the Tender ground and are therefore usually located below the cab. The sucking pumps have the advantage that they are more accessible. They are laterally screwed to the back boiler and are therefore protected from risk of frost.

A special design for the locomotive steam jet pumps is the Friedmann'sche Abdampfinjektor. Here is a part of the Maschinenabdampfs is used as motive steam for the injector. At low engine power with insufficient exhaust steam steam can also be mixed. At standstill, the engine of the Abdampfinjektor can also be operated with steam.

The steam jet pumps are characterized by simple design and very low wear, since, in contrast to the piston pumps have no moving parts. However, the water to be conveyed must have a sufficiently low temperature for reliable operation of the pump possess.

• Steam technology
• Steam boiler technology
• Jet pump
• Steam locomotive technology