Condensation locomotive
Condensation locomotives are a special type of steam locomotive .
The profitability of steam locomotives suffers to a large extent from the large amount of energy that is required to evaporate the boiler feed water in the first place. This energy and water is lost to operation when the steam is expelled from the chimney. This gave rise to the idea of recovery from the evaporation condensation early on .
Evaporative condensation technology
As early as 1854, some of the cylinder exhaust steam from locomotives was fed into the water tanks using the Kirchweger system in order to preheat the feed water. The system was improved around 1890 by first sending the exhaust steam through tubes fitted with cooling fins . This capacitor was mounted on the roof of the locomotive. These so-called dummy locomotives were used especially in America in urban tram traffic, but many locomotives of this type were also built in Great Britain , Germany and Russia .
In principle, the exhaust steam was passed through pipe systems in the vehicle , in which the steam condensed back into water by cooling and was then returned to the storage tank. The tube systems were partly equipped with cooling fins and were placed in the airstream to increase the cooling effect and thus the condensation. The arrangement of the cooling tubes in rows and parallel on the long flat walls of the locomotive tenders , some of which were particularly long for this purpose, was structurally particularly advantageous .
According to the later system from Henschel & Sohn , up to 95% of the boiler feed water could be recovered. The distillate was of great purity and considerably reduced the calcification of the boiler, the so-called scale formation. In addition, the machines could travel longer distances, depending on the type of locomotive and location of use, of up to 1200 km, without having to replenish feed water. Another advantage was that the boiler feed water was preheated to almost 100 ° C using the heat from the exhaust steam, which meant that less energy was required to make the water in the boiler evaporate.
In the individual, experimentally built locomotives with turbine drive instead of the piston steam engine , the steam cooling associated with the exhaust steam condensation created a negative pressure at the steam outlet of the turbine , which increased the output of the turbine.
In conventional locomotives, the cylinder exhaust is released through the blowpipe into the smoke chamber. On the way to the chimney, it pulls the smoke gases out of the fire box and at the same time creates the typical exhaust blow of the steam locomotive. In the condensation locomotive, the blowpipe was replaced by a turbine driven by exhaust steam with fan blades, which sucked in the flue gases and provided for the fire. Therefore, no exhaust beating can be heard from the condenser. The exhaust steam is fed into the condensers without any ash particles. However, the oil contained in the cylinder exhaust must be trapped with oil separators. The condensate can be de-oiled so well in two stages that it only contains 2 to 5 parts per thousand of oil. With appropriate maintenance of the locomotives, this value can be maintained over the entire operational period. The boiler water nevertheless tended to foam up because the superheated steam oil cannot be completely separated from the water and accumulates more and more in the largely closed circuit if the maintenance of the locomotives is neglected.
Preheating and condensation reduce water consumption by 90–95% and fuel savings of around 10%. When comparing a normal steam locomotive with a locomotive with exhaust steam condensation, there is no significant loss of power due to additional driven units such as fan and induced draft turbines. However, the operating costs are about twice as high because of the additional components to be maintained, so that it only made sense to use it on routes with insufficient water supply.
Applications
Altogether, including the steam turbine locomotive, more than 50 locomotive types with exhaust steam condensation are known:
- Special condensate wagons were developed for the Sudan Military Railway , but the operating materials continued to be carried on the locomotive, as the locomotive could also be driven without the condensate wagon.
- A side effect of the condensation was the reduction of the exhaust steam, which was an advantage when driving through tunnels and in urban areas. As early as 1880 , the London District Railway was using condensation locomotives in the subway shafts in order not to impair the climate for passengers as much there. Similar machines were also used in other English cities and on the Vienna Stadtbahn .
- Another side effect was that locomotives with a condensation device could not be detected as easily by low-flying pilots during war, especially in cold weather, because of the lower vapor plume.
- In the 1920s, turbine-powered steam locomotives were tested, such as the German T18 1001, T18 1002 (both based on the Zoelly system , Switzerland), T38 3225 (with a Ljungström turbine ) and similar locomotives in the USA , Switzerland and Sweden and in the UK . In order to improve the efficiency of the turbine and thus also the performance, the pressure difference in front of and behind the turbine had to be set up as large as possible, which could be brought about by an exhaust steam condensation. When the turbine is driven, the steam advantageously does not entrain any oil, since there are no parts in contact with the steam that have to be lubricated.
- In the 1930s, Henschel first delivered Henschel patent condenser locomotives to Argentina , the Soviet Union and Iraq ; later, Russian locomotive factories built over 1,400 locomotives using this technology.
- In the first half of the 1940s, a large number of class 52 locomotives of the Deutsche Reichsbahn were equipped with condenser tenders. They were initially used in war zones east of Germany, later also in northern France and Belgium. Due to the lack of a steam plume, they were not so easily noticed by the crews of enemy aircraft and could also be used in areas where the infrastructure for the intake of feed water was no longer available due to destruction. After the war , some machines of the 52 kon series were stationed in the Mainz-Bischofsheim depot. In 1950 there were 16 locomotives with the numbers 1853z, 1862, 1907, 1919, 1935, 1941, 1957, 1987z, 1997, 2001, 2005, 2013, 2014, 2015, 2017, 2020, 2021, 2022 and 2024z; other machines were stationed in Kirchweyhe, Duisburg-Wedau, Rosenheim, Munich-Ost and -HBf and Nördlingen, but were parked until mid-1954. In the area of what was later to become the GDR, 25 machines remained, which were used in the Cottbus area and converted into the normal version while retaining their company number. In Germany, the tender of 52 has been preserved in 1972 (source: Kondenslok.de), but no matching locomotive.
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- The South African Railway - Class 25 traveled the long distances through the Karoo Desert, where reducing water consumption was of great importance. These condenser locomotives were in use until about 1978; Then they too were replaced by diesel and electric locomotives over short distances, where they were dismantled to the standard 25 NC (non condensing) version because of the high operating costs (apart from two examples still preserved today). The six-axle condenser tenders were converted into conventional tenders with a very large water tank, which could be used to distinguish the converted locomotives from the ones that were delivered as 25 NC from the outset. One of the two preserved condenser locomotives, No. 3511, was last in service in 1992. Class 25 was preceded by a class 20 test locomotive, and the Rhodesian Railways also tested a locomotive.
Under the size and weight restrictions and burdened by the specific vibrations in railway operations, the maintenance costs significantly exceeded the savings due to the reduced fuel consumption. The advantages outweighed the advantages only on routes with a lack of water supply as well as during the war in Russia, e.g. by camouflaging trains by avoiding exhaust steam.
literature
- Peter Zander: Souvenirs from Maffei - about the development of steam locomotives with condensation equipment from Henschel & Sohn, Kassel . Part 1: Railway History No. 53 (2012), pp. 54–60.
- Hendrik Bloem, Fritz Wolff: 52 condens. Restless over the taxiway and the Rhine. In: BahnEpoche 22 spring 2017, Verlagsgruppe Bahn Fürstenfeldbruck 2017, ISSN 2194-4091, pp. 36–47.
- Jan-Henrik Peters: Kassel - Schöneweide - Eastern Front; The development of the condensation engine for use in World War II . Railway history No. 12 (2005), pp. 8-25.
- Leopold Niederstraßer (Ed.): Guide for the steam locomotive service . 9th edition (1957); Chapter 7.7 "Condenser Locomotives", pp. 384–388.
Web links
Individual evidence
- ↑ Zander.