What is a hydraulic relief valve? This is a device used in the hydraulic circuit to limit pressure in one or more locations to protect components. While setting and troubleshooting the hydraulic relief valve safely, important practices need to be followed. A relief valve will control the heat generation and limit the amount of power generation. Avoiding hydraulic component & machinery damage, and protecting workers from hazards are the tasks assigned to hydraulic relief valves. Simplicity and low cost are the major benefits of relief valve than other electrical and mechanical devices. Direct-acting and pilot-operated are the two different types of relief valves that can be used for low flow rates and high flow rates respectively.
How to Set Hydraulic Relief Valves?
Step 1: Review and understand the circuit diagram and adjust the circuit based on the diagram. Usually, relief valves are aligned close to the pump in parallel.
Step 2: Identify and cap off the hoses on the removed system side of the relief valve with correct JIC caps or plugs. It is not advised to cap off the return or tank side of the relief valve. Also, to reduce contamination and to prevent fluid loss, unused hoses and fittings in the circuit need to handle properly.
Step 3: Connect a pressure gauge in between the relief valve and pump to identify the line pressure.
Step 4: Loosen the pressure relief valve adjustment until the gauge reading is close to zero.
Step 5: The relief valve reading can be adjusted by turning the adjuster clockwise. When the mentioned reading on the circuit diagram is achieved, tight the adjuster lock nut securely.
Step 6: Shut down the machinery to release the pressure. Reconnect hoses after removing caps or plugs. Test the machinery for proper working.
Common Problems of Hydraulic Relief Valve
Overpressure, under pressure and valve leakage, are important reasons for hydraulic relief valve malfunction. If the system is not providing the desired pressure, it may be because of the wrong calibration. This issue can be fixed easily by re-calibrating the pressure of the hydraulic relief valve. Blocked discharge, fire exposure, check valve failure, and thermal expansion are common reasons for relief valve failure.
Leakage is always a serious concern in every hydraulic machinery. When a hydraulic system leaks, it will cost a lot in terms of fluid wastage, money and environmental hazards. Leakage is a result of poor maintenance, wear & tear, contamination, valve misalignment, etc…
Hydraulic Relief Valve Troubleshooting
When any indications of hydraulic relief valve failure are noticed, it is required to take necessary actions immediately to rectify this issue. If the relief valve problem is severe, it is better advised to replace the valve than repairing. For maintenance, it is necessary to release the system hydraulic pressure by shutting off the electric power supply to the circuit. Also, the workspace for system maintenance needs to be cleaned properly to avoid contamination. Fluid level, fluid properties, presence of contaminants, valve misalignment, seal failure, and others are important factors that need to be monitored.