Common Problems of a Hydraulic Relief Valve
Hydraulic systems, used for heavy equipment and other machinery, operate on a system of pumps and motors that use fluid. During operation, pressure builds up, with the pressure, at times, exceeding the limits of the system. For protection, a hydraulic relief valve activates itself when the pressure reaches a predetermined level, removing enough fluid to lower the pressure to an acceptable level. But that relief valve can suffer problems of its own during normal operation.
1. Improper setting
A major problem with any hydraulic system, whether it is brakes, power steering, construction machinery, or aviation, is overheating. According to Machinery Lubrication, a common cause of system overheating is the improper setting, or adjustment, of the relief valve. During normal operation the relief valve is closed, and stays closed until the pressure reaches a certain limit, which is determined by the setting. If the setting is not done correctly, then the valve will not activate, and the hydraulic fluid will overheat.
2. Spring failure
A hydraulic relief valve has a spring which is the activation mechanism. Thus, when the pressure reaches its limit, the spring opens the valve, and the excess fluid is diverted to a storage area. If the spring fails to deploy, then the relief valve will not work. According to Machine Tool Help, a cause of spring failure, to be checked before replacing the valve, is accumulation of particles due to normal wear and tear. A good cleaning, which should be done as part of normal maintenance, normally solves this problem.
3. Valve failure
The relief valve does not operate all the time. But when it does, it goes unnoticed since the pressure remains acceptable and the machinery continues to operate. So failure of the valve due to age or use can be a problem. Relief valves do not last forever, just like any other piece of equipment, so replacing them periodically will prevent their failure.