Patent ID: 7185491

Claim:
A steam engine comprising: a fluid container in which liquid-phase working fluid is filled, the fluid container having a loop pipe for forming a circular fluid passage through which the working fluid is moved back and forth; a heating device for heating the working fluid in the fluid container and vaporizing the same; a cooling device for cooling down and liquidizing steam, which is vaporized from the liquid-phase working fluid by the heating device; and an output device for producing a mechanical energy from self-excited movement of the working fluid generated by a repeated operation of vaporization of the working fluid by the heating device and liquefaction of the working fluid by the cooling device, wherein the heating device, the cooling device, and the output device are arranged in this order, and the heating device is located at a lower position than the cooling device, wherein the steam engine further comprises: a first valve arranged in a passage portion of the loop pipe, which is formed between the heating device and the output device and bypasses the cooling device, for opening and closing the passage portion; and a second valve arranged in another passage portion of the loop pipe, which is formed between the cooling device and the output device and bypasses the heating device, for opening and closing the other passage portion.