Abstract: A valve system for gas or liquid, comprising a hydraulic power transmission (19) where the pressure of hydraulic fluid is controlled by fluid pressure actuated members (15) and the changes of the fluid pressure actuate operative members (5, 7, 10) of the valve system, where the fluid pressure actuated members and the operative members comprise a tubular expandable bellows (10, 14, 25) with one gable (21) closed and the other (22) connected via tubes (11, 23) or similar to other expandable bellows (10, 14, 25) in the valve system and the thus arisen closed space in filled with hydraulic fluid (24), and that the expandable bellows (10) in the operative member stand in connection with a valve body (5) in a valve tube (1) and that the fluid pressure actuated members (15) is placed outside the valve tube (1). The valve body (5) is movable in the longitudinal direction of the valve tube (1) and in close contact with a seat (3) when the valve system is closed.

Abstract: A minimum flow valve device includes a housing providing a liquid passageway therethrough having an inlet end and an outlet end; a guide element mounted in the liquid passageway which provides an internal chamber that is open towards the inlet end of the liquid passageway, the guide element including a discharge orifice communicating with the internal chamber; an unloading pipe extending through the housing and communicating with the discharge orifice; an annular non-return valve element; and a valve sleeve member connected to the non-return valve element and extending within the internal chamber. The valve sleeve member includes orifices such that when the non-return valve element and the valve sleeve member are positioned to block liquid flow through the liquid passageway, liquid will flow through the discharge orifice and out the unloading pipe.