| 摘要 |
<p>The gun is for underwater hunting at long or short range, and incorporates means for additional easy compression of the pressurized air already in the air chamber. Typically, this can be in the form of a piston sliding in a tube closed at one end by a union incorporating an inflation valve. To give the extra compression, the piston can be thrust by a hydraulic pump comprising a tube, a valved piston, a lever and a non-return valve. The velocity ratio of the lever allows water, in which the pump is immersed, to be injected into the chamber on the other side of the first piston mentioned, thus forcing it rearwards and compressing the air behind it further.</p> |
