APPARATUS FOR PROTECTION AGAINST PRESSURE LOSS

摘要

The apparatus comprises a first chamber in which there is present a gaseous or vaporous medium under pressure and a second chamber which is predominantly filled with a liquid medium under a pressure independent from the pressure in the first chamber. In addition to these two chambers an intermediate chamber is filled in normal operation with substantially the same gaseous or vaporous medium at substantially the same pressure as present in the first chamber. The first chamber is connected through ducts via the intermediate chamber with the second chamber and at normal operation an unavoidable predetermined pressure drop is caused between said intermediate chamber and said second chamber. The pressure regulation is effected by a piston-operated shut off device adapted to assume an open and a closed position which device is disposed between the first and second chamber. The pressure present in the second chamber through the duct means will act on one end of the piston by means of the liquid medium present in the second chamber. The shut-off device is thereby moved into the normal open position. The pressure present in the first chamber by means of the connecting duct acts on the other end of the piston and will cause the shut-off device to move into the closed position if the pressure differential between the two pressures exceeds the predetermined pressure drop by a predetermined value. This will close the shut-off device and thus prevent an overrun from the first into the second chamber because of an excessive pressure drop in the second chamber.