Control valve
A control valve has a valve body and a flow control element preferably in the form of a disc, the valve body defining at least one inlet passage, the inlet passage culminating in an opening which is surrounded at least partially by a flow control surface, and the flow control element is so arranged as to be able to pass close to the flow control surface and across the opening to adjust the flow rate of at least one fluid which is caused to pass through the valve body, wherein the flow control element is constrained within the valve body by a stopping member, the stopping member being adapted to allow a positive clearance to exist between the flow control element and the flow control surface. The stopping member is preferably adjustable, allowing the positive clearance to be adjusted.
1. A control valve comprising a valve body and a flow control means, the valve body defining at least one inlet passage, the inlet passage culminating in an opening which is surrounded at least partially by a flow control surface, and the flow control means is so arranged as to be able to pass close to the flow control surface and across the opening to adjust the flow rate of at least one fluid which can pass through the said inlet passage, and the flow control means is constrained in a manner allowing allow a positive clearance to exist between the flow control means and the flow control surface, wherein the maximum extent of the positive clearance is determined by an adjustable stopping means which is movable relative to the valve body.
2. A control valve as claimed in claim 1 , wherein the adjustable stopping means includes a threaded device which cooperates with a mating thread associated with the valve body, such that rotation of the threaded device adjusts the positive clearance.
3. A control valve as claimed in claim 1 , wherein a locking means is provided to lock the position of the adjustable stopping means.
4. A control valve as claimed in claim 1 , wherein the flow control means is connected to a spindle, and the stopping means acts to constrain the spindle in at least one direction.
5. A control valve as claimed in claim 1 , wherein the positive clearance is in the range of 0.02 to 0.5 millimetres.
6. A control valve as claimed in claim 1 , wherein the flow control means is a substantially planar member in the shape of an incomplete disc.
7. A control valve as claimed in claim 6 , wherein the flow control means has the shape of an incomplete disc that is substantially semi-circular in shape.
8. A control valve as claimed in claim 1 , wherein the control valve includes an actuator which is operably connected to the flow control means and can be used to cause the flow control means to move.
9. A control valve as claimed in claim 1 , wherein the valve body defines two inlet passages and the control valve is adapted to control the mixing of two fluids.
10. A domestic mixing valve incorporating at least one control valve as claimed in claim 1 .