Abstract: Hydraulic systems are mainly used in mining, but due to the harsh environment of the mine, some problems have arisen during the use of hydraulic systems. Some of these problems are quite obvious, but there are also many hidden problems. If discovered in a timely manner, it will bring great safety hazards and cause significant economic losses. This article will conduct a detailed analysis of the problems in the hydraulic system of mining machinery, and propose corresponding solutions to some of them. Z will focus on effective measures to prevent pollution of hydraulic oil in the hydraulic system of mining machinery, in order to provide some reference and reference for everyone.
【 Keywords 】 Mining machinery; Hydraulic system; Common faults; Solution measures
Foreword
With the rapid development of mining machinery in our country, the use of hydraulic systems has become more widespread, which shows the important role of hydraulic systems in mining. However, due to the harsh environment in mines and long-term use of hydraulic systems, many problems may arise in hydraulic systems, and hydraulic systems are relatively sensitive to pollution. However, hydraulic systems generally work in a closed state, and once a fault occurs, it will bring great inconvenience to maintenance. As an important part of mining operations, it is of great significance to strengthen the handling of hydraulic system faults.
1. Guiding ideology for maintenance of common faults in hydraulic systems of mining machinery
To effectively avoid or reduce the occurrence of hydraulic failures and shorten the processing time, it is necessary for us to fully understand the causes of common failures in mining machinery hydraulic systems, familiarize ourselves with the characteristics of hydraulic components and the structure and working principles of hydraulic systems, and master the configuration relationship, working conditions, and environmental requirements of hydraulic components, accessories, and systems; Establish and improve equipment technical condition inspection, maintenance, repair system and fault technical files, accumulate usage data and equipment operation records; Proficient in learning and applying modern advanced diagnostic techniques, familiar with and selecting appropriate hydraulic system fault diagnosis and analysis methods, and possessing necessary testing instruments and methods.
2. Common faults in hydraulic systems of mining machinery
2.1 The pressure of the system is abnormal
Abnormal pressure in hydraulic systems usually includes the following aspects: insufficient pressure. The reasons for insufficient system pressure are multifaceted, such as low setting of pressure reducing valve, damage to overflow valve bypass valve, damage to pressure reducing valve, etc., all of which will cause the system pressure to be too low; Secondly, there are various factors that can cause pressure instability, such as the presence of air in the oil, damage to the relief valve, deterioration of spring rigidity, or failure of the inflation valve, all of which can lead to unstable system pressure; Thirdly, the main reason for high pressure is the pressure reducing valve. There are certain problems with the setting of overflow valves, which can cause serious damage to the machine and seriously affect its normal operation.
2.2 System malfunction
The main reasons for abnormal system operation are: the electromagnetic valve in the system pressure normal actuator has a fault, or the limit and sequence device cannot work properly or the modulation is not correct, the signal has no command, the amplifier cannot work well or the modulation is not quite equal, all of which will cause the normal actuator of the system pressure to malfunction; Secondly, if the action of the executing component is too slow due to the small flow rate output by the pump or system leakage, it will cause the component's execution ability to be low, resulting in the component's action being too slow; Thirdly, due to abnormal pressure, there may be gas mixed in the oil or issues with the command amplifier, which can cause irregular movements.
2.3 The hydraulic impact of the system is significant
The main reason for the large hydraulic impact in the system is that: the impact generated during reversing will generate instantaneous kinetic energy or the mutual conversion between potential energies, and even instantaneous impact; Secondly, hydraulic cylinders may generate strong shock waves during their movement due to braking or other reasons.
2.4 The temperature of the system oil is too high
The reasons for the high temperature of the system are multifaceted: the pressure is set too high; The pressure relief time is too short, and the valve leakage is too large; High pressure but low flow rate, low pressure but high flow rate; The unreasonable construction or insufficient quantity of the fuel tank will cause the temperature of the system oil to be too high, which will cause serious damage to the equipment.
2.5 The pump cannot produce oil
There are also various reasons why the pump cannot produce oil: it is not connected to the power supply or there is a fault in the circuit; Secondly, the motor trips due to excessive power; Thirdly, the sliding pair inside the pump gets stuck, which can also cause the pump to not produce oil; Fourthly, there are many reasons why the pump does not absorb oil, such as insufficient fuel in the tank, unopened suction valve on the pump, or equipment problems. All of these can cause the pump to fail to deliver oil.
2.6 The noise of the pump is too loud
There are many reasons for excessive pump noise, including the phenomenon of air suction and blockage of certain parts of the oil suction filter, which will increase the resistance; If the suction position is too high or the position of the oil in it is too low, it will cause the phenomenon of suction being empty. In addition, if the viscosity of the oil is too high or the speed of the pump is too high, it will cause excessive noise from the pump; Secondly, inhaling bubbles will also generate significant noise during machine operation; Thirdly, poor operation of the hydraulic pump can also generate significant pressure in the hydraulic system, and in addition, many other situations can cause noise.
3. Diagnostic methods for faults
3.1 Subjective diagnostic techniques
Subjective diagnostic techniques mainly refer to the analysis and judgment of some faults by technicians based on their work experience. The methods generally adopted include intuitive experience method, parameter measurement method, and logical analysis method.
3.2 Intuitive experience method
This method mainly refers to maintenance personnel based on years of experience? Experience is gained by observing equipment and listening to its operating conditions to identify potential faults. Generally, this involves observing the operating speed of certain components, the height of the liquid level, or the condition of the oil, as well as listening for noise during the operation of the electric motor and the screaming sound of the overflow valve. This will effectively solve common problems in the equipment.
3.3 Parameter measurement method
This method mainly records the working parameters of each component during the operation of the equipment. And compare it with the normal value, which will help identify potential issues and solve them in a timely manner.
3.4 Logical analysis method
This method mainly establishes a certain logical connection between components and system equipment, so that once a fault occurs, it will be observed in the corresponding other equipment or from the system.
3.5 Diagnostic technology of instruments
Mainly through instrument display or computer analysis of possible faults in the system. There are many types of instruments, such as ordinary, specialized, and comprehensive. There are also many methods for instrument detection, such as vibration diagnosis, acoustic diagnosis, thermodynamic diagnosis, etc. These methods can accurately diagnose the problems that occur, and can also achieve online diagnosis and prevention work.
4. Measures to prevent hydraulic oil contamination
4.1 Keep hydraulic oil clean before use
Hydraulic oil can be contaminated by external factors during transportation and storage. Newly purchased hydraulic oil may appear clean, but it is actually very "dirty" and must be left to stand for several days before being filtered and added to the hydraulic system for use.
4.2 Keep the hydraulic system clean after assembly and before operation
Hydraulic components must be cleaned thoroughly during the processing and assembly process. The hydraulic system should be thoroughly cleaned after assembly and before operation. The oil used in the Z easy to use system should be cleaned. During cleaning, the oil tank must be completely sealed except for the ventilation valve L (with a dust cover), and the sealing components must not have burrs or edges.
4.3 Keep hydraulic oil clean during operation
Hydraulic oil is subject to environmental pollution during operation, so efforts should be made to prevent the intrusion of air and moisture during work. To completely eliminate the intrusion of water, air, and pollutants, a sealed oil tank is used, and an air filter is added to the ventilation hole to prevent dust, abrasives, and coolant from entering. The seals and capsules in the accumulator should be regularly inspected and replaced.
4.4 Use appropriate oil filters
This is an important means of controlling hydraulic oil pollution. According to the requirements of the equipment, different filtering methods, accuracies, and structures of oil filters should be selected in the hydraulic system, and the oil filters and oil tanks should be regularly inspected and cleaned.
4.5 Regularly replace hydraulic oil
Before replacing with new oil, the fuel tank must be cleaned once. If the system is dirty, it can be cleaned with kerosene and drained before injecting new oil.
4.6 Control the working temperature of hydraulic oil
The working temperature of hydraulic oil is too high, which is not conducive to hydraulic devices. Hydraulic oil itself will also accelerate deterioration, produce various products, and shorten its service life. Generally, the working temperature of hydraulic systems should be controlled below 65 ℃, and the hydraulic system of machine tools should be controlled below 55 ℃. Task implementation is to select hydraulic oil correctly and reasonably for the hydraulic system of jacks, which is a prerequisite for ensuring the high efficiency and normal operation of hydraulic equipment. When selecting hydraulic oil, it is recommended to choose hydraulic oil according to the variety number recommended by the hydraulic component manufacturer's samples and instructions, or to comprehensively consider factors such as the working pressure, working temperature, type of hydraulic components, and economy of the hydraulic system. Generally, the appropriate hydraulic oil variety should be selected first, and then the brand of hydraulic oil (i.e. viscosity grade) should be selected.). At the same time, special requirements for the working conditions of the hydraulic system should also be considered. For example, systems working in cold regions require high viscosity index, good low-temperature fluidity, and low freezing point of the oil; The servo system requires pure oil quality and low compressibility; The high-pressure system requires the oil to have good anti-wear properties. When selecting hydraulic oil, viscosity is an important parameter. Firstly, the type of hydraulic oil should be selected based on its working properties and environmental requirements.
5. Conclusion
To make the hydraulic system work better, it is necessary for the staff to have a good grasp of the corresponding components in the hydraulic system. In addition, it is necessary to establish a sound technical condition inspection and maintenance file on the mine, and to regularly maintain and clean the hydraulic system. Only in this way can the hydraulic system work better.
2025 May 3rd Week VAFEM Product Recommendation
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