1. Field of the Invention
The present invention relates to an arrangement for a submarine vehicle, comprising a thermal, steam-powered engine, a condenser for condensing the exhaust given off by the engine, a compressor for compressing a non-condensable fraction of the exhaust, and an exhaust outlet for draining the compressed exhaust fraction into the water surrounding the vessel. The expression submarine vessel is used here to denote primarily, but not exclusively, a torpedo.
2. Description of the Prior Art
In conventional submarine torpedos, which are powered by thermal engines, an arrangement is provided which generates water vapour by burning a fuel, usually a liquid hydrocarbon. The oxygen for the combustion process is taken from an accompanying oxygen supply, for example air, hydrogen peroxide or liquid oxygen. The gases produced by combustion and the water vapour generated at a high temperature are led into the engine and are converted into mechanical work. The exhaust gases from the engine are usually discharged at a point on top of the extreme stern of the torpedo.
If the exhaust gases are to leave the torpedo, then the gas pressure must be higher than the existing depth pressure. Since the torpedoes must be capable of being used against targets moving at different depths, they are fitted with an adjustable depth regulator. When the torpedo is set for a greater depth, the depth pressure which the exhaust gases must overcome will also be greater. A high back-pressure will reduce the operating efficiency (power output) of the torpedo engine and will increase the noise level due to the fact that the pressure inside the operating cylinder of the engine will be high when the outlet to the sea is opened.
It has accordingly been proposed, see U.S. Pat. No. 3,973,392, that only the non-condensable fraction of the exhaust gas be drained, instead of draining all the exhaust. Since the former usually constitutes only a small proportion of the exhaust gas, it will consequently be necessary to sacrifice only a very small amount of energy in order to expel the exhaust gas from the torpedo.
It has been found, however, that the noise radiated by the engine is troublesome even in torpedoes of this kind.