Abstract: An expansion tank to be connected to a pipe system filled or with a liquid is disclosed. The expansion tank includes at least one connection opening for a liquid pipe. The tank has a main valve to close off the connection opening at a defined difference in pressure between the interior of the tank and the connection opening and/or at a defined liquid level in the tank. The tank also has an additional valve for closing off a channel extending through the closure member of the main valve from the interior of the tank to the connection opening. The additional valve is closed during normal operation of the expansion tank and is open if the difference in pressure between the interior of the tank and the connection opening is higher than the original pressure in the expansion tank.

Abstract: An expansion tank (1) which is intended to be connected to a pipe system which is filled or is to be filled with liquid, comprises a substantially closed tank (2) having at least a first connection opening (6) for connection to a liquid pipe, a second connection opening for connection to a source of pressurized gas (14), and an element (8) which can move inside the tank and is designed to move with the interface (11) between liquid (9) and gas (10) in the tank. The tank is provided, at the location of the second connection opening, with a valve assembly (7) which can open and close the second connection opening and can be actuated by the movable element (8) in the tank.

Abstract: An expansion tank 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 with at least one connection opening for a liquid pipe. The tank is provided with a main valve inside the tank having a valve seat and a closure member and being designed to close off the connection opening at a defined difference between the pressure in the interior of the tank and the pressure in the connection opening and/or at a defined liquid level in the tank. The tank is further provided with an additional valve for closing off a channel or passage extending through the closure member of the main valve from the interior of the tank to the connection opening.