Hydraulics and Pneumatics: Unit II: Hydraulic Actuators and Control Components
simple (or direct-acting) pressure relief valve
Hydraulic Actuators and Control Components - Hydraulics and Pneumatics
The construction and operation of a simple poppet (ball)-type direct-acting pressure valve is illustrated in Fig.6.16(a).
SIMPLE (OR DIRECT-ACTING) PRESSURE RELIEF VALVE 1. Construction and Operation The construction and operation of a simple poppet (ball)-type direct-acting pressure valve is illustrated in Fig.6.16(a). It has one inlet port which is normally closed under the influence of spring force. An adjustable spring load provides the pressure setting of the relief valve. When the inlet pressure overcomes the force exerted by the spring, the valve opens and vents to the atmosphere or back to the sump. Thus the relief valve protects the other elements in the system from excessive pressure by diverting the excess fluid to the sump or atmosphere when the system pressure tends to exceed the preset level. The direct-acting type of relief valves have a ball, poppet or a sliding spool working against a spring. As the inlet pressure decreases, the valve closes again. The adjusting screw cap is used to adjust the pressure limit and to vary the spring force. 2. Graphic Symbol Fig.6.16(b) represents the graphic symbol of simple relief valve. 3. Application of Simple Relief Valves The direct-acting pressure relief valves are used where the flow rate and the system pressure are low. 4. Limitation of Simple Relief Valves. When the required system pressure is high, a heavier spring is required. Because of the use of heavier spring, the problem of valve chatter or pressure fluctuations are very common.
Hydraulics and Pneumatics: Unit II: Hydraulic Actuators and Control Components : Tag: : Hydraulic Actuators and Control Components - Hydraulics and Pneumatics - simple (or direct-acting) pressure relief valve
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Hydraulics and Pneumatics
ME3492 4th semester Mechanical Dept | 2021 Regulation | 4th Semester Mechanical Dept 2021 Regulation