fLOW CONTROL VALVES
Flow control valves come in all shapes, sizes, and designs. Their basic function, how ever, is the same-to control flow of air. Flow control valves for hydraulic systems (liquids under pressure) are of the same basic design. A typical example of a flow control valve is the simple water faucet installed in homes.
Globe valves and needle valves are standard designs used for flow control. Unidirectional flow control valves control the flow in one direction but permit free flow in the other direction. Pressure-compensated flow control valves are also manufactured. These valves control the amount of flow and will maintain a constant flow at different pressures. These valves are ideal for some applications but should be used only when required because of their higher cost.
The check valve is another type of flow control valve. The function of a check valve is to permit flow in only one direction. A very common function of flow control valves is to control the speed of cylinders and air motors . The speed of cylinders or air motors depends on the amount of air, which can be controlled by flow control valves.