Area damage

In the case of piston steam engines, surface damage refers to the release of energy which is caused by the contact of the hot steam with cool and thus heat (energy) dissipating surfaces. The cooling of these surfaces is caused, for example, by poor insulation and the resulting heat release to the outside air.

Another area damage that cannot be remedied by insulation measures also occurs in the working cylinders of the steam engine , because the expansion of the steam during the working stroke also significantly reduces the temperature of the steam. The next time the work area is filled, these cooled surfaces absorb heat from the freshly introduced steam, which is then no longer available for work.

The effect of surface damage is particularly critical when using wet steam or saturated steam , which is particularly easy to cool due to its high water droplet content. Another associated disadvantage is that when saturated steam is used, a lot of rainwater remains in the cylinders and damages the lubricating film .

Remedy: In terms of design, the contact surfaces with the outside air can be kept small and well insulated. In addition, the expansion of the working steam can be distributed over two or three cylinders connected in series ( composite effect ) and / or the working steam can be heated in a steam dryer or superheater to such an extent that the condensation of the steam no longer begins on the working stroke.