Maintenance and management issues of hydraulic coal mine anchor drill RIGS
In general, the selection of hydraulic system oil should meet the following requirements: It must not contain steam, air or other impurities that are prone to vaporization or vaporization. It has excellent lubricating performance and a very high liquid film strength. Has a high degree of chemical stability; Appropriate viscosity and good viscosity-temperature performance. For drilling rig hydraulic oil, it iS recommended to use Lanchou or Shangchou hydraulic oil (200 40n1m ² /iS). In cases where the source is difficult, 30 # mechanical oil can be used in summer and 20# mechanical oil in winter.
The hazards and preventive measures of oil contamination in hydraulic systems Hydraulic system contamination is a major cause of hydraulic failures. Contaminants mixed into the system will accelerate the wear, abrasion, burning and even damage of hydraulic parts, or cause valve malfunction or noise. Contaminants can clog the throttle holes or throttling gaps of hydraulic components, alter the working performance of the hydraulic system, cause malfunction or even complete failure, and lead to misoperation and accidents. Dust particles in the hydraulic cylinder will accelerate the damage of seals, scratch the inner surface of the cylinder barrel, increase leakage, cause insufficient thrust or unstable operation, crawling, reduced speed, and produce abnormal sounds and vibrations. It may also cause the filter screen to clog, making it difficult for the hydraulic pump to draw in oil, resulting in poor oil return and causing cavitation, vibration and noise. When the clogging is severe, the filter screen will be punctured due to excessive resistance, completely losing its filtering function and creating a vicious cycle in the hydraulic system. Therefore, it is necessary to strengthen management, prevent oil contamination, and ensure the safe and reliable operation of the hydraulic system. (1) The hazards of oil contamination to the hydraulic system: blocking the fit clearances between the relatively moving parts of hydraulic components such as pumps and valves, blocking the throttle holes, damping holes and valve ports in hydraulic components, and preventing the components from working normally; When dirt enters the fit clearance between the relatively moving parts of hydraulic components, it will scratch the mating surfaces, damage the accuracy and surface roughness of the mating surfaces, accelerate wear, increase component leakage, and sometimes cause the valve core to get stuck, resulting in component failure. Excessive dirt in the oil causes the oil pump to suck oil: (1) The oil filter screen at the suction point is clogged, resulting in excessive suction resistance, which makes the oil pump unable to work normally, generating noise and vibration; The dirt in the oil will cause it to deteriorate. When water mixes into the oil, it will cause the oil to emulsify, reduce its lubricating performance, increase its acid value, shorten the service life of components and increase leakage. (2) Measures to prevent oil contamination. Among the common faults in hydraulic systems, many are caused by unclean oil. Therefore, keeping the oil clean is an important aspect of maintaining hydraulic equipment. The measures to prevent oil contamination are as follows: The area around the oil tank should be kept clean and the oil tank should be covered and sealed. The oil in the fuel tank should be replaced regularly. Generally, the oil should be changed after a cumulative operation of 1,000 hours. When oiling, it should pass through a filter with a mesh size of 120 or more. Regularly inspect and clean the filter; Regularly clean the hydraulic components with kerosene and unblock the pipelines. Regularly inspect the pipe joints and sealing devices between pipelines and components.
3. Hazards of Air Entering Hydraulic Systems and Preventive Measures: The oil used in hydraulic systems has very low compressibility, but the compressibility of low-pressure air is very high, approximately 10,000 times that of the oil. Even if there is a small amount of air in the system, its impact is significant and can cause system malfunctions. (1) Hazards of air entering the hydraulic system. The air dissolved in the hydraulic fluid will escape from the oil when the pressure is low, causing noise in the hydraulic system and creating bubbles and cavitation. When reaching the high-pressure area, under the impact of the pressure oil, the bubble skin is shattered, causing a sharp increase in pressure and generating noise in the system. When the vaporization in the oil is rapidly compressed, it releases a large amount of heat, causing local overheating and damaging the hydraulic components and hydraulic oil. The air in the oil is highly compressible, causing the working components to crawl and vibrate, thus disrupting the smoothness of operation. A large number of air bubbles mixed in the oil will deteriorate the oil, reduce its service life and accelerate the wear of components. (2) Measures to prevent air from entering the hydraulic system. Depending on the different reasons for air entering the hydraulic system, the following points should be noted during use and maintenance: Regularly check the oil level in the oil tank to ensure there is sufficient oil in the tank.
4: Maintain from the appearance, such as whether the joints are loose, whether there is oil leakage, and whether there are cracks in the pipeline, etc. Before starting the pump, check whether the oil is added as required and whether the oil temperature is normal. When the temperature is below 10℃, it should be operated without load for more than 20 minutes (especially in winter). Pump start-up and post-start-up inspection: When starting the pump, it should be started in a start-stop manner to raise the oil temperature and ensure the smooth operation of the driving device before entering normal use. After the pump starts, it is also necessary to check whether there are any adverse phenomena such as cavitation, overheating and bubbles.
