Created on:2021-07-27 09:58

Failure analysis of hydraulic support of coal mine equipment_ Measures to prevent column damage

Failure analysis of hydraulic support of coal mine equipment_ Measures to prevent column damage

(1) Measures to prevent column damage

The normal damage of the equipment in use is inevitable, and the column is no exception, such as the corrosion problem, contact surface wear problem and deplating problem mentioned in the following table. Although these damage forms account for a large proportion, the column will not be scrapped. The current maintenance methods can completely restore its performance, but several damage forms such as cylinder expansion and bending should be avoided. The preventive measures are as follows.

① For the problems in the design of the manufacturer (such as cylinder expansion, poor stability, etc.), it is suggested that the manufacturer increase the safety factor of the design to make the selected safety factor meet the requirements of the design manual (strength calculation of cylinder block n ≥ 5, stability calculation of piston rod n ≥ 6).

② In order to prevent the transverse force of the column, the user and maintenance unit should try to prevent the bracket from tilting. The user should regularly clean up the foreign matters in the column socket, reasonably adjust the distance between the supports, and regularly detect the action pressure of the column safety valve. The maintenance unit shall strictly implement the scrapping standard of four-bar pin, so as to make the repaired hydraulic support conform to the provisions on support deflection in the maintenance standard for coal mine electromechanical equipment formulated by the former Ministry of coal (the provisions are: the ratio of the height of the support in the horizontal position to the deviation size between the vertical line of the middle point of the front pillar socket of the top beam and the center line of the base shall not exceed 28:1).

 

Damage form of column

Form of damage

所占比例

 

损坏形式

所占比例

外缸、中缸局部胀缸,上、下腔串液

3%

 

导向套与缸体连接处的密封面损坏

1.5%

中缸、活柱弯曲

4%

 

外缸、中缸内壁锈蚀、磨损

5%

外缸、中缸内壁轴向划伤

3%

 

电镀面碰伤、划伤、镀层脱落

20%

导向套与缸体连接螺纹损坏

1.5%

 

 

 

 

 

(2) Reuse of damaged column

In the process of support overhaul, the overhaul cost of the column normally accounts for 20% of the overhaul cost of the whole hydraulic support. In special cases, the overhaul cost is quite amazing when batch scrapping occurs. In order to reduce waste and obtain better economic benefits, it is necessary to repair the hydraulic cylinder. The basic treatment method is as follows.

① The normal damaged column shall be repaired according to the general electroplating process.

② The bent and deformed movable column and middle cylinder are reshaped by press on the special worktable to meet the straightness requirements of the maintenance standard.

③ The middle cylinder of expansion cylinder was forced to compress after annealing treatment, and then transformed into a single telescopic belt mechanical extension column.

④ Special seal is used for outer and middle cylinders with slightly worn inner wall and enlarged cylinder mouth.

⑤ Due to the influence of the current electroplating process, the effect of repairing the scratch and serious corrosion on the inner wall of the cylinder mouth is not good, and further measures need to be explored.

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