hydraulic valves

As our technology advances, engineered machineries continue to undergo developments. Fact is, this can be applied particularly on hydraulic machineries commonly used in large and heavy equipment. Hydraulic machinery refers to equipment that use high-pressure fluid to accomplish work in industrial fields.

For a hydraulic machine to function, hydraulic fluid is pumped to a high-pressure level and then moved throughout the machines by different actuators. High-pressure hydraulic fluid is transmitted throughout the machine via hydraulic motors and hydraulic cylinders. The fluid is controlled directly or automatically by hydraulic valves and distributed through hoses and tubes.

Afterwards, the pumped hydraulic fluid flows to the actuators or motors then returns to a reservoir. The fluid is then filtered and re-pumped. The path taken by hydraulic fluid to circulate is called hydraulic circuit. Hydraulic circuits are of several types. An open center circuit is one example. This kind uses pumps to supply a continuous flow.

In open center circuits, the flow is returned to the tank through the control valve's open center. When the control valve is centered it provides an open return path to the tank and the fluid is not pumped to a high pressure. But, if the control valve is actuated, it routes fluid to and from an actuator and to the tank. The fluid's pressure will rise to meet any resistance. If the pressure rises too high, fluid returns to tank through a pressure relief valve and multiple control valves may be stacked in series. This type of circuit is practical to use because it uses inexpensive, constant displacement pumps.

Closed center circuits, on the other hand, supply full pressure to the control valves whether these are actuated or not. The pumps vary in flow rate, pumping very little hydraulic fluid until the operator actuates a valve. The valve's spool doesn't need an open center return path to tank. Multiple valves can be connected in a parallel arrangement and system pressure is equal for all valves.