What is the base work of preventive maintenance in hydraulic system?

The hydraulic system is widely used in processing equipment due to its unique advantages. A large number of hydraulic control components and hydraulic actuators are distributed in the processing and rolling equipment, and they play a vital role in the precision control and transmission control of the equipment.

However, the stability of the hydraulic system also directly affects the stability of the overall equipment, production efficiency, product quality and maintenance costs.To further regulate the hydraulic system maintenance and management should be based on scientific, standardized, data and information to perform routine maintenance and management of the hydraulic system.

Following is the basic work of preventive maintenance of hydraulic system.

(一) Hydraulic system point inspection

All hydraulic systems should be included in the daily point inspection management of the equipment. The hydraulic system point inspection items should cover the following 4 elements: “liquid level, pressure, temperature, vibration”.

From power components, control components, executive components to auxiliary components, all should be included in the inspection scope.The frequency of specific inspections can be determined according to the working conditions and strictly included in the maintenance procedures of each machine train.

The point inspection data is uniformly recorded in the informationized equipment management system, which is convenient for closed-loop management and control of abnormal problems and subsequent data query and analysis.

1. Inspection of liquid level points

All hydraulic system oil tanks shall have level control standards. The minimum liquid level of the hydraulic system oil tank shall not be lower than 50% of the actual height of the oil tank, and the maximum liquid level shall not be higher than 80% of the actual height of the oil tank.

In addition to checking the liquid level, record the relevant data and deal with the liquid level fluctuations compared to the previous time and within 24 hours.

2. Inspection of pressure points

Machine train equipment should be based on the hydraulic control schematic diagram, establish a hydraulic system “pressure list” and incorporate it into periodic control.

The “list of pressure values” shall cover the rated pressure of the hydraulic system, working pressure, working pressure of each control point, and pressure values of relevant relief valves.

And according to the equipment working conditions, the above-mentioned “pressure point inspection” work is reasonably divided to different positions of personnel who perform the inspection work.

3. Inspection of temperature points

The hydraulic system of the machine train equipment should establish a “temperature list” and include it in the daily inspection and control. The “temperature list” should cover key hydraulic components and parts.

According to the working conditions of the equipment, each machine train classifies the work of “temperature point inspection”, divides the frequency, and reasonably divides the work to the personnel of different positions who perform the inspection work.

4. Vibration point inspection

Vibration of the hydraulic system pipeline should be paid attention to during the point inspection. When the hydraulic system is running, except for the vibration of the hose, all hard pipes should not have visible vibration.

5. Dynamic monitoring system

For key parts, an equipment dynamic monitoring system with intelligent monitoring and analysis can be introduced, such as real-time monitoring of the temperature and vibration of the pump body.

(二)Preventive maintenance

In the work machine equipment maintenance procedures, a special “hydraulic system preventive maintenance list” should be formulated, which covers the performance inspection and maintenance of the main components of the hydraulic system, the maintenance of the cleaning filter system, the check of the pressure value of the pump and valve, the maintenance of the seal and the leakage Troubleshoot and check tightness of pipe clamps and pipe joints.

The preventive maintenance methods for the four major components of the hydraulic system are as follows:

1. Power components

As the power component of the hydraulic system, the hydraulic pump should be tested and maintained regularly.

2. Control components

Hydraulic system control components mainly perform preventive maintenance for pressure valves and flow valves. Regular pressure reducing valves, relief valves, and throttle valves should be tested once per year for the pressure regulation and throttling performance of the valves. The above-mentioned valve parts in key parts should be tested every six months.

3. operating units

The preventive maintenance of hydraulic cylinders and hydraulic motor actuators is mainly for the inspection of piston rod wear and deformation, and regular inspection or replacement of seals.In principle, the seals of hydraulic cylinders should be disassembled and inspected every 5 years, and replaced or continued to be used according to the inspection conditions.

4. Auxiliary components
(1) Fuel tank

All oil tanks of high-pressure servo hydraulic system should be cleaned at least once a year, and all oil tanks of low-pressure auxiliary hydraulic system should be cleaned once every two years.The inside of all hydraulic system oil tanks should be separated from the oil suction side and the oil return side according to the design standards, and the height of the pump suction port from the bottom of the oil tank should not be less than twice the diameter of the suction port pipe.

(2) Filter

All hydraulic systems should use filters with differential pressure indicators, and perform filter replacement and maintenance work based on the alarm conditions of the differential pressure indicators. The differential pressure indicators should be checked every six months.

The filtration accuracy of the filter element at the outlet of the pump should not be less than 7μm, and the filtration accuracy of the circulating filter system of the pump station should not be less than 5μm.

(3) Plate cooler

The heat exchange effect of the plate cooler should be checked once a month, and the execution records and data comparison of the temperature of the cooling water in and out, and the temperature of the in and out oil should be integrated. According to the data chain comparison and the cooling effect in the same season of the previous year, the plate cooler shall be disassembled and maintained.

In principle, the plate cooler should be disassembled and maintained at least once every three years.Periodic inspection and cleaning of Y-type filters of all plate cooler inlet pipes should be finished per quarter.

(4) Pipeline

The pipeline maintenance work of the hydraulic system is mainly carried out for pipe joint inspection, pipe clamp tightening inspection, hose inspection and so on.

All pipe joints and pipe clamps shall be classified and regularly tightened inspection according to the distribution of valve stations and equipment working conditions. The longest period of tightening inspection shall not exceed 1 time/quarter.The fastening of pipe joints and pipe clamps should be based on the “131” principle, that is, focus on the control of a line above the strip, within 3 meters of the execution end, and a power source output end.

The visual inspection of the hose should be carried out once per month, which can be carried out in conjunction with the periodic short-term regular inspection of the equipment.

5. Accumulator

All accumulators shall perform periodic inspection of airbag pressure, and the inspection cycle is once per quarter. The air bag inflation pressure is 70% to 75% of the working pressure of the control oil circuit of the accumulator.

(三)Leakage control of hydraulic system

  1. The machine train equipment should establish a standardized leakage control ledger, and the ledger information should cover the specific leakage location, leakage degree, approximate leakage volume, leakage point seal parameters and other information.

2. The machine train equipment should establish a list of common and key control leak points, and form a leak detection operation guide to guide the operators and electric clamp maintenance personnel to perform the hydraulic system leak detection work.

3. The electric fitters who    perform the leakage treatment of the hydraulic system shall be trained to perform the norms.

 4. For the preventive maintenance of leaks, a dedicated person should be designated to be responsible for the closed-loop management and control of standardized operations and problems.

5. For the 5S management of hydraulic system leakage, a division of responsibility system can be adopted, such as the system of appointing people and points.

 6. If the hydraulic system leakage management and control of the current month fails to achieve the control target, a relevant leakage analysis meeting should be organized and the meeting minutes should be formed; the person in charge and the completion time of the problem improvement item should be clarified, and closed-loop control and follow-up assessment should be implemented.

hydraulic hoses              test point            hydraulic test fittings              parker hydraulic test fittings           hydraulic test ports             hydraulic test hoses               hydraulic equipment corporation                 pressure gauge fittings                 test points              pressure gauge connection             hydraulic fluid test point                parker fittings              connecting threads test point            hydraulic test port fittings           hydraulic coupling and hose           mini hydraulic presses           shock valves          press valves          flange valve          test point        fluid hydraulics         fluid connectors           hydraulic quick disconnect fittings         flange manufacturer        fluid power solutions            pressure couplings              fluid coupler            hydraulic flanges                hydraulic pressure test      hydraulic equipment supplier            hydraulic fittings hose coupling                hose fitting             hydraulic test kit                     hydraulic test point                              hydraulic quick coupler              pressure test point              hydraulic coupling               hydraulic test port                    pressure gauge adaptor



Contact Us Now

*We respect your confidentiality and all information are protected