Hydraulic control valve

Hydraulic control valve

Hydraulic control valves are used to modify fluid flow or pressure rate in a process system which also can be used to control and direct the oil or fluid from the time it leaves the pump until it starts on its return to the reservoir in a hydraulic circuit. Hydraulic valves as used in industrial applications are built in several pressure ranges. The typical applications at present are in the range of 0 to 1500 lb per sq in., but the trend is toward higher pressures. Various types of valves are used in hydraulic systems to control or regulate the flow medium. Basically valves are expected to control: Blocking or stopping of flow, Direction of flow, Pressure of flow media, Flow quantity Types of Hydraulic Control Valves.

The various parameters that need to be controlled in the case of oil energy are firstly, in a hydraulic machine the actuators make to and fro motion. Hence the direction of oil feeding the cylinder or motor needs to be reversed. This means that the direction of oil flow is an essential aspect of hydraulic operation. This is achieved by direction control valves. Secondly, oil energy does the work due to pressure in the oil system. In a mechanical or hydraulic system there may be a need to increase or decrease the oil pressure depending on the specific requirement. Hence a group of valves called pressure control valves have been designed. Finally, the speed of the actuators needs to be altered as per operational requirement.

The control valve is almost always the first one encountered by the oil or fluid after it leaves the pump. From that point on throughout the circuit, the type of valve employed depends upon the design of the circuit. In a very simple circuit, the only other valve used will probably be the master control valve. In a complex circuit the oil may flow through a sequence valve, master control valve, reducing valve, flow control valve, check valve and several others before it finally returns to the reservoir.