Working of Hydraulic Relief Valves

21 September 2010- Hydraulic mechanism has made our lives very easier. The steering wheel in our vehicle, the farm tractors, log splitter, construction machines etc. , there is the application of hydraulic mechanism. Regardless of the application, hydraulics are all basically the same. There is use of a fluid pump to increases the pressure of the hydraulic fluid, which move either a motor or a long cylinder to perform the required task. An important component of a hydraulic system is the hydraulic valve. If for some reason the hydraulic pump does not work and there is too much of pressure, the excess pressure must be released so that there is no personnel injury and damages to the equipment. A relief valve is used just for this situation.

How does relief valve works?

When the hydraulic system reaches an unsafe or excessive level, pressure relief valves are used. If these valves are not used, then there is every chance of the hoses being damaged or hydraulically driven motors or cylinders being blown apart with high pressure. Fixed pressure relief valves are used as a safety device for any kind of very high or excessive pressure situation. There are different varieties of relief valves. Some are available for one time use only. They must be replaced when they have performed the task. There are others which can be reused for releasing the high-pressure fluid. There are certain other varieties where the valves may allow the fluid to go back into the reservoir tank for further use. In such valves, the small sized hydraulic systems release the fluid to outside of the sealed system. Whatever the case, the use of a pressure relief valve is a clear indication that there is a failure in the hydraulic system.

Adjustable relief valves

Besides the fixed relief valves, adjustable relief valves are also widely used in hydraulic systems. Usually the the big size hydraulic presses can use the adjustable valve as a control mechanism to apply only so much pressure for pressing or bending metal. The adjustable relief valve let a certain pressure to reach in the sealed system. When this pressure is reached, the hydraulic fluid is released back into the reservoir tank and the fluid is reused. This helps in maintaining the pressure at a particular gauze reading for a proper amount of force to be enforced on to the cylinders. Generally, all hydraulic presses make use of adjustable pressure relief valve for the operation of the cylinders.