Abstract: A variable flow rate valve system adjusts flow rate using the flow medium itself by creating differential pressures that determine a position of a valve member in relation to an associated valve seat. The valve system includes a diaphragm that divides a valve chamber into a control chamber and a flow chamber connected with an inlet. A valve body is connected with the diaphragm and cooperates with a valve seat to modulate flow from the inlet to an outlet and through the flow chamber. A first pilot valve in a first bypass extends between the outlet and the control chamber, and a second pilot valve in a second bypass extends between the inlet and the control chamber. The valves are controlled to selectively open or close respective bypasses to vary the flow through the flow chamber between a fully open and a fully closed condition in response to a control signal.

Abstract: A variable flow rate valve system adjusts flow rate using the flow medium itself by creating differential pressures that determine a position of a valve member in relation to an associated valve seat. The valve system includes a diaphragm that divides a valve chamber into a control chamber and a flow chamber connected with an inlet. A valve body is connected with the diaphragm and cooperates with a valve seat to modulate flow from the inlet to an outlet and through the flow chamber. A first pilot valve in a first bypass extends between the outlet and the control chamber, and a second pilot valve in a second bypass extends between the inlet and the control chamber. The valves are controlled to selectively open or close respective bypasses to vary the flow through the flow chamber between a fully open and a fully closed condition in response to a control signal.