Patent ID: 6155531
Filing Date: 2000-12-05
Classification: F15B,F16K

Abstract:
A proportional control valve for turning a main valve shaft to any desired position between fully open and fully closed comprisinga housing,control valve shaft means connectable to said main valve shaft for causing said main valve shaft to rotate in response to rotation of said control valve shaft means,piston means operatively connected to said control valve shaft means, said housing having first and second chambers separated by said piston means, said piston means being movable in a first direction for increasing the volume of said first chamber while decreasing the volume of said second chamber and in a second direction for increasing the volume of said second chamber while decreasing the volume of said first chamber, said control valve shaft means being rotatable in one of a clockwise direction and a counter-clockwise direction for opening said main valve in proportion to said piston movement in a first direction and rotatable in the other of a clockwise direction and a counter-clockwise direction for proportionally closing said main valve in proportion to said piston movement in a second direction,solenoid means mounted on said housing for selectively pressurizing one of said first and second chambers thereby causing said piston means to reduce the other of said first and second chambers and enlarge said one chamber, andreturn means disposed in the other of said first and second chambers and in operative engagement with said piston means for urging said piston means to reduce said one of said chambers and enlarge said other chamber,whereby the rotational position of said control valve shaft means is fixed by the position of said piston means when the opposing forces of the pressure and said return means are in equilibrium.