Expansion tank with valve

摘要

An expansion tank (1) which is intended to be connected to a pipe system which is filled or is to be filled with a liquid, comprises a closed tank (2) with at least one connection opening (3) for a liquid pipe. The tank (2) is provided with a main valve (51) inside the tank (2) having a valve seat ((52) and a closure member (53) and being designed to close off the connection opening (3) at a defined difference between the pressure in the interior of the tank (2) and the pressure in the connection opening (3) and/or at a defined liquid level (57) in the tank (2). The tank (2) is further provided with an additional valve (71) for closing off a channel or passage (72) extending through the closure member (53) of the main valve from the interior of the tank (2) to the connection opening (3). The additional valve (71) is closed during normal operation of the expansion tank (1) when connected to a pipe system filled with liquid and is open if the difference between the pressure in the interior of the tank (2) and the pressure the connection opening (3) is higher than the original pressure in the expansion tank (1) when it was delivered ex works. <IMAGE>