Control valve

A control valve (1) for controlling liquid flow in a heating and/or cooling installation, the control valve (1) comprising:

• a valve housing (2) with an inlet (3) and an outlet (4),
• a flow area regulator for regulating a flow area of at least one variable size entry opening through which the liquid flowing through the control valve (1) from the inlet (3) to the outlet (4) has to pass,
• the flow regulator comprising at least one valve member (20,24) that is movable between a fully open position that corresponds to a largest possible flow area of the entry opening and a fully closed position that corresponds to the smallest possible flow area of the entry opening, in which said entry opening is essentially closed,
• a pressure regulating arrangement downstream of the flow area regulator with a pressure chamber (8) downstream of the flow area regulator and upstream of the pressure regulating arrangement,
• said pressure regulating arrangement being configured for maintaining an essentially constant differential pressure between the inlet pressure (P1) in the inlet (3) and the intermediate pressure (P2) in the pressure chamber (8),
• said pressure regulating arrangement comprising a movable throttle member (47) that cooperates with a plurality of exit openings (43),
• said movable throttle member (47) substantially closes said exit openings (43) in one of its positions,
• characterized by comprising at least one drain passage (54) connecting the pressure chamber (8) to the outlet (4) with the drain passage (54) still allowing liquid in the pressure chamber (8) to drain to the outlet (4) when said movable throttle member (47) is in said position where it closes said exit openings (43), said drain passage (54) connecting to the outlet (4) via one or more of the exit openings (43).

A control valve (1) for controlling liquid flow in a heating and/or cooling installation, the control valve (1) comprising:

• a valve housing (2) with an inlet (3) and an outlet (4),
• a flow area regulator for regulating a flow area of at least one variable size entry opening through which the liquid flowing through the control valve (1) from the inlet (3) to the outlet (4) has to pass,
• the flow regulator comprising at least one valve member (20,24) that is movable between a fully open position that corresponds to a largest possible flow area of the entry opening and a fully closed position that corresponds to the smallest possible flow area of the entry opening, in which said entry opening is essentially closed,
• a pressure regulating arrangement downstream of the flow area regulator with a pressure chamber (8) downstream of the flow area regulator and upstream of the pressure regulating arrangement,
• said pressure regulating arrangement being configured for maintaining an essentially constant differential pressure between the inlet pressure (P1) in the inlet (3) and the intermediate pressure (P2) in the pressure chamber (8),
• said pressure regulating arrangement comprising a movable throttle member (47) that cooperates with a plurality of exit openings (43),
• said movable throttle member (47) substantially closes said exit openings (43) in one of its positions,
• characterized by comprising at least one drain passage (54) connecting the pressure chamber (8) to the outlet (4) with the drain passage (54) still allowing liquid in the pressure chamber (8) to drain to the outlet (4) when said movable throttle member (47) is in said position where it closes said exit openings (43), said movable throttle member comprising a rolling diaphragm (47) that cooperates with said plurality of exit openings (43), and said rolling diaphragm (47) substantially closing the exit holes (43) in a position of the rolling diaphragm with the drain passage (54) still allowing liquid in the pressure chamber (8) to drain to the outlet (4).