General reasons for leakage on mechanical equipment

General causes of mechanical equipment leakage

1) Design reasons One of the main reasons for equipment leakage is unreasonable design. For example, in the external spline milling machine produced by the machine tool factory, more than 40 oil leaks were found after inspection. Almost all of these leaks were caused by poor design. The main reasons for the above problems are: insufficient attention to this aspect of the product design, designers are not familiar with the sealing technology, and even leave inherent weaknesses in the design, resulting in equipment leakage. For the user, it is More difficult to manage.

        This unreasonable design is usually manifested in: First, the selected sealing structure is not compatible with the working pressure, working temperature, medium characteristics, and environmental conditions; second, not paying attention to anti-corrosion, anti-vibration, pressure equalization, dredging, etc. The measures are only one-sided consideration of plugging, for example, ventilation, oil return, and liquid guiding devices are not considered in the design.

2) Problems in equipment manufacturing. Poor manufacturing and processing of equipment is often an important cause of leakage. Among them are mainly the problems of machining accuracy and surface roughness. For example, gear pumps, hydraulic valves, etc. all use clearance to control the leakage. If the manufacturing accuracy does not meet the design requirements, it will increase the internal leakage, reduce the oil delivery efficiency or affect the accuracy of the action. The surface roughness should be determined according to the sealing method, location and selection of seals, etc. Too high or low is not good. If the sealing surface is too rough, it is easy to cause interface leakage. If the surface roughness is too small, it will sometimes cause leakage. For example, when liquid sealant or anaerobic sealant is used, when the sealing surface roughness Ra is less than 0.8㏕, the sealing effect will not be good; O-ring seal is used to seal, such as If the shaft roughness Ra is less than 0.025㏕, the sealing effect is no longer improved, but even decreased. In addition, equipment leakage is also related to the sealing surface processing method. If the sealing surface has radial machining tool marks, it is easier to leak than axial turning machining tool marks.

3) The problem of the equipment installer The quality of equipment installation also has a greater impact on leakage. For example, the assembly process is chaotic, the installation technique is not good, and the scraping and tightening of bolts do not comply with the technical regulations, etc., which are also one of the causes of equipment leakage. Practice has proved that if a piece of the same mechanical equipment is installed by a skilled technician, it will often have better performance and is not easy to leak, and it will be easy to leak if it is installed by an inexperienced person.

4) Reasons for sealing elements and materials Improper selection of sealing elements and materials often results in short service life of the sealing device, poor sealing performance, and easy leakage of the equipment. In recent years, new sealing materials and their products have continued to appear, and their performance is many times better than traditional sealing elements and materials, such as polytetrafluoroethylene, expanded graphite, liquid sealant, Avène sealant, etc. The applications have been quite effective .

5) Reasons for operation and maintenance Improper operation and poor maintenance are the direct causes of equipment leakage, such as excessive refueling, clogged air vents, uncompressed packing seal glands, and do not deal with them in time when the joints appear slightly exposed, sealing elements If it is damaged, replace it in time. If the felt ring for sealing is not immersed and dried, replace it. Use fillers and gaskets that fail in time. If you are not familiar with or even understand the correct use of various seals and sealants, it will cause equipment leakage. .

        In short, there are many reasons for the leakage of mechanical equipment, and the various reasons include a variety of influencing factors, which sometimes overlap each other and are more complicated. Therefore, it is necessary to make a specific analysis of each influencing factor to find out the main cause of equipment oil leakage.