| 摘要 |
<p>Appts. for inducing the opening of a valve blocked by ice, partic. on a tank contg. a liquefied gas, is of the type comprising a screw-jack, rotation of which creates a thrust tending to detach the valve from its seat. The device is disposed on the part of the valve lever outside the body and incorporates two threaded elements and a return mechanism. The first threaded element is mounted pivoting on the lever. The second screwes on to the first. It includes means of rotating it and is capable of bearing on a part of the body of the valve. The return mechanism is able to bring the threaded elements back from their unblocking position to an inactive position in which they do not hinder the maneuvering of the valve lever. Device overcomes the fault of existing valves incorporating a screw-jack in which, if the operator forgets to bring the jack back to its initial position after opening the valve, the travel of the latter is reduced and it cannot return to the closed position.</p> |
