Created on:2021-12-28 10:13

Maintenance of hydraulic system and storage of vulnerable parts

Maintenance of hydraulic system and storage of vulnerable parts

Maintenance of hydraulic system

Like other machinery, the hydraulic device needs maintenance, regular inspection and replacement of parts to keep its accuracy and performance in the best state and give full play to the best function of the system. The maintenance shall be carried out according to the operating instructions, operating procedures or special requirements, and the maintenance records shall be made.

1. Establish and improve maintenance records

Maintenance record refers to the health record card during the operation of hydraulic equipment, which can generally specify the following contents.

(1) Hydraulic oil consumption record. This is conducive to determining the oil demand, strengthening cost accounting and quantitative management through oil consumption analysis. Timely refuel the system according to the records. It can also be used as the basis for oil leakage fault analysis to find and eliminate the leakage in time.

(2) Original operation records, including the records of pump pressure, temperature, vibration, etc. the working conditions of the pump can be mastered through analysis and comparison.

(3) Pollution records. The blockage of oil filter will lead to cavitation of hydraulic pump, increase of system vibration and noise and other faults. Through the analysis of dirt blockage and particle composition of the oil filter, the system wear, wear parts and hydraulic oil pollution can be judged, the hidden trouble can be reminded and supervised, and the problems existing in oil pollution management can be solved in time.

(4) Other records. In case of abnormal pressure, valve and actuator action failure and other accidents, records shall be made in order to find out the symptom of the fault and provide the original basis for fault analysis and troubleshooting.

2. Establish a regular test system for hydraulic oil

The regular test system mainly includes: sampling time, sampling method, analysis and test method of sample oil, oil change standard, etc.

The sampling of hydraulic oil shall be once a month, and that of ordinary hydraulic system shall be once every three months. In case of frequent pollution of the oil filter or water inflow into the system, the hydraulic oil shall be sampled and tested at any time.

3. Establish and improve feasible maintenance system

(1) Daily maintenance system. Daily maintenance refers to the routine inspection of hydraulic equipment by operators before, during and after use. The equipment is usually observed and inspected with the help of sensory organs such as eyes, ears, hands and nose and instruments installed on the equipment (such as pressure gauge, etc.).

1) Inspection before use.

① Inspection of oil quantity in the oil tank: observe from the oil level gauge, oil mark and oil window, and the oil quantity shall be determined above the oil mark line.

② Inspection of room temperature and oil temperature: generally, it can only be carried out in winter and summer. When the room temperature is lower than 10 ℃, preheat the oil; When the room temperature is higher than 35 ℃, heat dissipation measures shall be considered.

③ Inspection of pressure gauge: observe whether the pointer of the pressure gauge swings seriously, whether it can return to zero position and measuring range.

2) Inspection in use.

① When starting the overflow valve, confirm that it is adjusted to the minimum pressure, that is, loosen the pressure regulating handle, and then jog the oil pump to observe whether there are abnormal conditions. Such as whether the pump can deliver oil, whether there is abnormal sound, whether the pressure gauge fluctuates severely, etc.

② Adjust and check whether the regulating pressure of the overflow valve can rise and fall continuously and evenly, and then adjust to the set pressure after everything is normal.

③ Inspection of oil temperature, hydraulic pump shell temperature and electromagnet temperature: when the oil temperature is 20-55 ℃, it is normal, and the temperature of hydraulic pump shell is 10-30 ℃ higher than the room temperature. The temperature rise of electromagnet is shown on the electromagnet nameplate.

④ Oil leakage inspection; Check the oil leakage at the joint surface of pump, output shaft, pipe joint, the joint between oil cylinder piston rod and end cover, all sides of oil tank, and the installation surface, installation thread and installation flange of various valve components.

⑤ Noise and vibration inspection: check whether the oil pump has "cluck" sound, whether the electromagnet has "buzzing" sound, whether the pipeline has vibration sound, whether the oil cylinder has impact sound during reversing, and whether the pipeline is loose.

⑥ Inspection of pressure gauge.

3) Inspection before off duty (after shutdown).

① Oil level inspection of oil tank: if the oil level drops a lot after shutdown, find out where the reduced oil leaks and flows (ground, trench or cooling water tank).

② Clean and scrub the dirt on the exposed surface of oil tank, hydraulic components, oil cylinder, etc.

③ The handle position of each valve shall be restored to the "pressure relief", "stop", "back" and other positions.

④ If it is convenient, touch the oil filter by hand to confirm the dirt blockage, and make records and disposal.

⑤ Turn off the power and fill in the shift handover record.

Although the above routine inspection and maintenance will take some time and energy, through inspection and observation of phenomena such as a little leakage and a little pressure change, faults and accident signs can be found as soon as possible, and some simple treatment can be made to eliminate potential faults and prevent major faults and accidents, which is really twice the result with half the effort. Therefore, it is suggested that the daily maintenance work should be included in the responsibility system for assessment.

(2) Regular maintenance and inspection system. This work is a planned preventive inspection dominated by professional maintenance personnel and attended by production workers. Like daily inspection, it is a work to make equipment maintenance more reliable and longer life, and to find fault signs and trends as soon as possible. In addition to human senses, certain inspection tools and instruments should be used to find and record equipment abnormalities, damage, wear and oil leakage, so as to determine the repair parts, parts to be replaced, type and time of repair, and arrange the repair plan accordingly. Regular maintenance and inspection often cooperate with cleaning and oil change. Regular maintenance and inspection can make daily inspection easier.

1) Quarterly (3 months) maintenance inspection.

① Check in detail according to the contents of daily inspection.

② Disassemble and clean the oil filter and analyze the dirt.

③ Check the cylinder piston rod surface for strain.

2) Maintenance inspection every 6 months (half a year).

① Conduct general inspection according to quarterly inspection items.

② Check the coupling between motor and oil pump, replace the flexible ring and add grease if necessary.

③ Disassembly and inspection of solenoid valve.

④ Disassembly and inspection of pressure valve.

⑤ Disassembly and inspection of flow valve.

⑥ Check the filling gas pressure of the accumulator.

⑦ Hydraulic oil contamination check (change oil if necessary).

⑧ Pipeline inspection. In particular, check whether the rubber or nylon hose is damaged or broken.

3) Annual maintenance inspection.

① Conduct general inspection according to the above items.

② Disassemble and repair the oil pump, replace the worn parts of the oil pump or replace the pump with a new one.

③ Dismantle and repair the oil cylinder, and replace the oil cylinder seal and damaged parts.

④ Clean and change the oil tank.

⑤ Check and tighten the sealing reliability of pipe joints.

⑥ Disassemble and check the overflow valve and dispose according to the situation.

⑦ Clean or replace the air filter.

(3) Comprehensive inspection. Comprehensive inspection shall be conducted every two or several years. The content and scope of the inspection shall be extensive, and a thorough and comprehensive inspection shall be conducted as far as possible. All hydraulic components shall be disassembled through comprehensive inspection, and repaired or replaced according to the conditions and problems found after disassembly. During comprehensive inspection, the repaired or replaced hydraulic parts shall be recorded. These can be used as a reference for finding and analyzing faults and preparing spare parts in the future. Before comprehensive inspection, vulnerable parts such as seals, filter elements, leather bags of accumulators, pipe joints, hard hoses and electromagnets shall be prepared in advance, because these parts can be expected to be replaced. During the comprehensive inspection, if it is found that the operating instructions of hydraulic equipment are lost, try to prepare and file them.

Storage of vulnerable parts

The stored vulnerable parts shall meet the requirements of specification, model and material, and maximize the interchangeability of vulnerable parts. Special wearing parts or non-standard parts shall be prepared in advance.

The type and quantity of vulnerable parts stored depend on the type of system, the number of equipment, the service life of vulnerable parts, the change or aging time of vulnerable parts material, the supply of vulnerable parts, storage place, economic situation and other factors. During the storage of vulnerable parts, pay attention to rust prevention and dust prevention to prevent deformation and deterioration, especially some spare parts prone to chemical changes (seals, hydraulic oil, etc.) should be properly stored. All spare parts shall be marked with specification, model and use position for maintenance personnel to find.

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