The purpose of the Kirchweger condenser (German: ''Kirchweger-Kondensationseinrichtung'' or ''Kirchwegersche Abdampfkondensation'') was to preheat

feedwater Boiler feedwater is an essential part of boiler operations. The feed water is put into the steam drum from a feed pump. In the steam drum the feed water is then turned into steam from the heat. After the steam is used it is then dumped to the ma ...

in a steam locomotive using the exhaust steam from the engine. It was invented in 1850 by Heinrich Kirchweger. A similar system was developed by Rohrbeck.

Overview

Exhaust steam was extracted from the steam chest and fed through a 100 mm diameter pipe under the locomotive to the tender. There the steam was fed directly into the feedwater, which thus heated up to boiling point. The remaining steam was allowed to escape to atmosphere through a second chimney on the tender. The quantity of steam could be regulated using a cock on the tender. The Rohrbeck system differed in detail from the Kirchweger condenser, in which steam was removed at the

blast pipe The blastpipe is part of the exhaust system of a steam locomotive that discharges exhaust steam from the cylinders into the smokebox beneath the chimney in order to increase the draught through the fire. History The primacy of discovery of ...

and led away along the top of the

boiler A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, centr ...

. The system was regulated by a throttle valve on the blast pipe.

Fuel savings

Using such a system, fuel savings of between 10 and 20% were possible, depending on the operating conditions. In some circumstances even as much as 30% could be saved. The

Lower Silesian-Märkisch Railway Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Gloucestershire, England See also *Nizhny Nizhny (russian: Ни́жний; masculine), Nizhnyaya (; feminine), or Nizhneye (russian: Ни́� ...

(''Niederschlesisch-Märkische Eisenbahn'') put this saving at 7.5% on its locomotives.

Contamination

However the contamination of

boiler feedwater Boiler feedwater is an essential part of boiler operations. The feed water is put into the steam drum from a feed pump. In the steam drum the feed water is then turned into steam from the heat. After the steam is used it is then dumped to the ma ...

with foreign bodies was a problem. Old sources report erosion of the boiler plates which was caused by fatty acids contained in the lubricant accompanying the exhaust steam. On the other hand, the formation of scale in the boiler was delayed because a proportion of the boiler scale constituents had already been left behind in the tender.

Withdrawal

With the introduction of

injector An injector is a system of ducting and nozzles used to direct the flow of a high-pressure fluid in such a way that a lower pressure fluid is entrained in the jet and carried through a duct to a region of higher pressure. It is a fluid-dynamic ...

s for feeding water into the boiler, exhaust steam condensers were taken out of use from the 1860s, because injectors could only handle cold water. By about 1880, around 900 German locomotives had been fitted with condensing apparatus.

References

;General * R. von Helmholtz, W. Staby: ''Die Entwicklung der Lokomotive im Gebiete des Vereins Deutscher Eisenbahnverwaltungen, 1. Band, 1835 - 1880''; Verlag von R. Oldenburg, München und Berlin, 1930 {{Steam engine configurations Steam locomotive technologies Locomotive parts