Function and adjustment method of superimposed relief valve

Stacked relief valve: full analysis of principle, adjustment and maintenance

As the core control component in the hydraulic system, the superimposed relief valve assumes the important responsibility of stabilizing the system pressure and ensuring the safe operation of the equipment. With its unique structural design and flexible adjustment method, it has been widely used in industrial automation, construction machinery and other fields. This article will start from the basic concepts and systematically explain its adjustment methods and maintenance points to help readers deeply master this key technology.

1. Core characteristics of superimposed relief valve

The superimposed relief valve adopts a modular design concept and consists of a main valve core assembly and a superimposed installation valve block. Its working principle is based on the pressure balance theory in fluid mechanics, and it controls the pressure and flow in the hydraulic system by adjusting the valve opening. When the system pressure exceeds the set value, the valve core automatically opens and leads excess hydraulic oil back to the tank to maintain system pressure stability. This design not only simplifies the hydraulic pipeline layout, but also achieves accurate pressure control and rapid response.

2. Detailed explanation of diversified adjustment methods

(1) Manual adjustment: basic control mode

The manual adjustment method is widely used in situations that do not require high control accuracy due to its intuitive operation and low cost. The specific operation process is as follows:

Pre-tightening positioning: First tighten the handle positioning nut to ensure that the handle does not rotate accidentally during the adjustment process.

Pressure setting: Turn the adjustment handle clockwise to increase the system pressure setting, and turn it counterclockwise to decrease the pressure. Each rotation usually corresponds to a specific pressure change, which needs to be determined by referring to the product manual.

Lock confirmation: After the adjustment is in place, tighten the positioning nut again to prevent the pressure setting value from drifting during operation.

Typical applications: Pressure initialization of machine tool hydraulic systems, pressure adjustment of simple hydraulic devices.

(2) Hydraulic remote adjustment: high-precision control solution

For complex systems that require remote control or dynamic adjustment, hydraulic remote adjustment shows unique advantages. Its working principle is to output a control signal through the proportional pressure valve to achieve stepless adjustment of the pressure of the relief valve.

Signal connection: Connect the proportional pressure valve to the hydraulic system control circuit to ensure stable signal transmission.

Pressure programming: The target pressure value is set through the controller, and the proportional valve outputs the corresponding pressure signal.

Dynamic response: After the overflow valve receives the signal, the valve core position is adjusted in real time, so that the system pressure can quickly reach and stabilize at the set value.

Technical advantages: fast response speed (up to milliseconds), high adjustment accuracy (±1%FS), and can achieve pressure program control.

3. The art of balance adjustment of bidirectional overflow valve

As a special structural form, the bidirectional relief valve has two independent working oil ports, which can realize independent pressure control of forward and reverse flow. The key points of its adjustment are as follows:

(1) Dividing pressure setting

Forward adjustment: Rotate the forward pressure adjustment knob, observe the forward pressure gauge, and gradually adjust to the design value.

Reverse adjustment: Adjust the reverse pressure in the same way to ensure that the pressure setting in both directions meets the process requirements.

(Bi) Two-way pressure balance

Synchronous observation: During the adjustment process, the pressure gauge display in both directions needs to be monitored simultaneously.

Fine-tuning balance: By adjusting the two knobs alternately, the forward and reverse pressure difference is controlled within the allowable range (usually ≤ 5%).

Dynamic verification: Simulate actual working conditions and check the pressure stability during bidirectional flow.

Application scenarios: hydraulic motor control circuit, symmetrical actuator pressure management.

4. Scientific maintenance and fault prevention

(1) Key points of daily inspection

Pressure stability monitoring: Regularly record system pressure data and analyze pressure fluctuations trends.

Leak inspection: Visually check whether there is hydraulic oil leakage at the joint surface of the valve body and the pipe joint.

Noise evaluation: Monitor abnormal sound during operation to determine whether the valve core is stuck or worn.

(II) Regular maintenance projects

Cleaning operation: Use hydraulic oil to clean the dirt on the valve body every 500 working hours.

Seal replacement: Replace consumable parts such as O-rings every 2000 working hours.

Performance testing: Use special testing equipment to verify that the pressure regulation characteristics meet the standards.

(III) Common fault handling

Pressure adjustment failure: Check whether the adjustment spring is broken or the valve core is blocked by impurities.

System pressure is low: check whether the overflow valve setting value is too low or the pump source is insufficient.

Large pressure fluctuations: Check the cleanliness of hydraulic oil, or replace the damping hole.

5. Outlook on technological development

As hydraulic technology develops towards intelligence, superimposed relief valves are integrating more advanced functions:

Electro-hydraulic integration: integrates pressure sensor and electronic control unit to realize closed-loop pressure control.

Adaptive adjustment: Automatically adjust the pressure setting value according to system load changes.

Troubleshooting: Built-in self-test program can monitor and warning for potential faults in real time.

Conclusion

The accurate adjustment and scientific maintenance of the superimposed relief valve are the key to ensuring the efficient and reliable operation of the hydraulic system. By mastering its working principle, adjustment method and maintenance key points, technicians can effectively improve equipment performance and extend service life. In the future, with the advancement of materials science and control technology, superimposed relief valves will surely show a broader application prospect.