The hydraulic relief valve and the hydraulic pressure reducing valve are two important pressure management devices in a hydraulic system. Whether you are engaged in machinery manufacturing, automobile manufacturing, or other industries, mastering the method of adjusting and setting hydraulic relief and pressure reducing valves is indispensable to building or maintaining your hydraulic systems. This article will give you a detailed introduction on how to adjust and set them.
What are Hydraulic Relief Valve and Pressure Reducing Valve?
The hydraulic relief valve is a safety device in a hydraulic system. It is usually located at the pump outlet to release the pressure and restrict the high pressure. This device can protect the whole hydraulic system from overpressure, reduce the damage to components in the system, and therefore ensure the power output and efficiency of the hydraulic system.
As a pressure control device, the hydraulic pressure reducing valve can effectively balance the valve internal spring and the downstream pressure, drain the hydraulic oil into the hydraulic tank, thereby delivering low pressure downstream. This can provide your hydraulic system with stable power, allowing the stable operation of your machine.
Hydraulic Relief Valve Adjust and Set
Step 1:Tools Preparation
At the beginning of adjusting and setting the valve, you should prepare the tools. Usually, you should prepare a screwdriver, wench, and a hydraulic pressure gauge. Most importantly, take adequate personal protection, like wearing gloves and safety glasses. These protective devices can safeguard you against unexpected incidents.
Step 2:Determine the Valve Position and Pressure
After all tools are prepared, you should watch the operating manual or drawings to determine the relief valve position. What’s more, you should consult the manual to confirm the specified pressure setting, ensuring your hydraulic system can operate normally.
Step 3:Hydraulic Pressure Gauge Installation
Install the hydraulic pressure gauge between the pump and the relief valve. This can help you read the pressure value and observe its variation.
Step 4:Pressure Relief and Adjustment
In this step, you should loosen the jam nut first to relieve the pressure. And you will see the value on the pressure gauge is 0. After that, increase or decrease the pressure by rotating the relief valve screw. Usually, you can rotate clockwise the screw to increase relief pressure and counterclockwise to decrease relief pressure. Slowly and gradually rotate the screw until it achieves the pressure you need.
Step 5:Testing
After adjusting the hydraulic relief valve, you can start the machine and test the pressure. The pressure in the circuit can’t be higher than the set pressure.
Step 6: Finish and Tighten the Jam Nut
When you have completed all the steps and the pressure has achieved your requirements, you can tighten the jam nut and restart the machine for your use.
Notice During Adjusting and Setting
You can‘t tighten or loosen the pressure relief valve screw completely. This may result in overcompensation of the pressure and damage the valve. Usually, a 1/4 turn will make a noticeable pressure difference, so you should rotate in small, gradual steps to adjust the valve.
The Possible Problems with the Hydraulic Relief Valve
When adjusting the hydraulic relief valve, there may be some problems. You should find and solve these problems as early as possible.
Can Not Reach the Set Pressure
One of the reasons is that the pressure relief valve releases pressure in advance, so the pressure of the hydraulic system may lower the set pressure. You can ask a technician to recalibrate the pressure relief valve. The other reason may be that your relief valve is damaged and the seals are worn. This can also result in the leakage of flow and low pressure.
Overhigh Pressure
This may occur when the pressure relief valve is stuck. The radial unbalanced force of the hydraulic oil may cause the valve to be stuck. You can enhance the cleanness of the hydraulic oil, which can reduce the risk of being stuck. What’s more, you should tighten the valve screw as required by the design. Because the valve may deform under stress and therefore get stuck.
Hydraulic Relief Valve Malfuncton
The pressure relief valve may be worn or malfunction after long use. For example, a broken spring may result in the unwork of a pressure relief valve. Therefore, you should maintain or replace the pressure relief valve in time.
Hydraulic Pressure Reducing Valve Adjust and Set
Step 1:Tools Preparation
You need to prepare a screwdriver, a wrench, and a hydraulic pressure gauge. What’s more, wear protective equipment to ensure your safety.
Step 2:Determine the Valve Position
Watch the operating manual or drawings to determine the hydraulic pressure valve position. Select the appropriate pressure value of your pressure reducing valve according to the operating manual.
Step 3:Hydraulic Pressure Gauge Installation
Disconnect the power supply, and install a pressure gauge in the downstream of the valve, helping you observe if the pressure is overhigh.
Step 4:Pressure Relief and Adjustment
Then you should loosen the locking nut so that you can rotate the adjustable scrow. It is the same as the relief valve; clockwise rotation can increase pressure, while counterclockwise rotation decreases pressure. You should notice that it is enough to rotate the adjusting screw slightly at a time, then gradually increase or decrease the pressure according to your system specifications.
Step 5:Testing
Restart the hydraulic system, and observe if the pressure achieves your requirement. If the pressure value is not aligned with your needs, you can readjust the pressure reducing valve until you achieve your needs. After that, measure the pressure multiple times, ensuring the pressure value is stable.
Step 6: Finish and Tighten the Locking Nut
The last step is to tighten the locking nut after all settings and adjustments have been completed.
Notice During Adjusting and Setting
You should notice that if the outlet pressure is higher than the set pressure, then you need to loosen the locking nut again and adjust the pressure from low pressure to high pressure.
Attention After Adjustment
The Pressure Inspection
After completing adjusting and setting your hydraulic pressure reducing valve, you should inspect if the pressure can achieve your set pressure value. This can determine whether your adjustments are effective.
The Flow Inspection
Inspect the flow in the circuit. You can detect flow by monitoring pressure readings. If the flow is stable, then the pressure will also be stable. While the flow is unstable, this means the adjustment may bring this instability.
Leakage Detection
You should inspect the pressure reducing valve and other connections, ensuring there is no leakage. A slight leakage can greatly influence the adjustment and set of your hydraulic pressure reducing valve.
Conclusion
In conclusion, adjusting and setting hydraulic relief/pressure reducing valves is an essential process to enhance the efficiency and safety of your hydraulic system. If you have any questions about these steps or want to learn more about the hydraulic system, feel free to contact us or visit Target Hydraulics for more information.
FAQ
What is the Difference Between a Hydraulic Pressure Relief Valve and a Hydraulic Pressure Reducing Valve?
These two valves are both pressure management devices; the following are their main differences.
| Hydraulic Relief Valve | Hydraulic Pressure Reducing Valve | |
| Function | As a safety device, release the redundant pressure, ensuring the safety of the hydraulic system. | As a pressure control device, it actively reduces upstream pressure to a stable outlet pressure to meet the pressure requirements of the hydraulic system |
| Operating Status | Opens when necessary, after relieving the pressure to a specified level, it will close. | Usually kept open, continuously and actively adjust the pressure. |
| Components Design | Simple design, usually contains a spring spool or a ball, sealing the valve by spring force. | Complex design and usually contains a valve housing, a pressure Spring, and a Piston slide valve. |
Can the Hydraulic Relief Valve be reset?
Yes, the hydraulic relief valve is a safety device; it only turns on when necessary. When the pressure is overhigh, it will take effect and relieve the redundant pressure. When the pressure reaches the specified level, it will reset. This is repeated to ensure the safe and efficient operation of the hydraulic system.
Can the Hydraulic Relief And Pressure Reducing Valves be Adjusted During Operation?
No, you can’t adjust these valves during their operation. This may greatly influence your safety. As the hydraulic system operates at high pressure, this may release high pressure and hurt you. What’s more, the released high pressure will also damage the machine. And the pressure will be unstable; therefore, it will influence your adjustment and setting.
