The cause of leakage of hydraulic support column jack

Leakage of hydraulic support column jack is mainly manifested in: cylinder port leakage and piston leakage. Cylinder port leakage is the leakage caused by the poor sealing performance between the guide sleeve and cylinder barrel, guide sleeve and piston rod.

Piston leakage mainly includes the piston and piston rod, piston and cylinder barrel between the sealing performance caused by the leakage. The leakage caused by the hydraulic support column jack is mainly due to the failure of the hydraulic seals and mechanical design and manufacturing unreasonable.

A. the reason for the hydraulic seals

Hydraulic seals mainly include dust rings, guide rings, O-shaped seals and their matching retaining rings, combination seals. Seals in the hydraulic support column jack work process plays a very important sealing role, the merits of its performance directly determines the performance of the hydraulic support column jack. In the process of hydraulic support to complete the support, due to the unreasonable structure of the seals, wear and installation reasons, there will often be leakage, this situation will make the hydraulic support work efficiency is reduced.

1. the structure of the hydraulic seals is not reasonable design

Seals need a suitable working environment, and require good heat resistance, gas tightness, strong wear resistance, water resistance, different materials have different requirements for the operating environment of the seal. Hydraulic support jack in the working pressure of the seal, working temperature and the need to withstand the impact load are key points to consider in the use of the seal. For example, the seal material selection is not reasonable, neither to ensure the hardness, toughness, elasticity and other physical properties of the seal, but also to ensure its wear resistance, ease of assembly and other performance. Seal groove size is not reasonable, resulting in easy damage to the seal, which will also reduce the sealing performance of the column jack.

2. the wear and tear of hydraulic seals

Wear of the hydraulic seals include wear and tear of the seals of the hydraulic support column jack and wear caused by emulsion pollution. Seals made of rubber and other materials, due to prolonged use prone to aging, cracking, damage, etc.; parts are damaged by the collision in the course of work, will scratch the seals, may also cause leakage.

(1) Wear of seals. The higher the relative motion speed of the seal surface, the higher the friction and wear between the hydraulic seal and the seal surface, which is easy to reduce the sealing performance of the hydraulic seal; the higher the working pressure of the emulsion, the additional contact stress generated on the surface of the hydraulic seal is bound to be relatively large, which will easily lead to premature wear of the hydraulic seal, thus reducing the sealing performance of the hydraulic seal.

(2) The pollution of emulsion leads to the wear of hydraulic seals. Downhole rock dust, coal dust, moist air and water droplets are very easy to pollute the emulsion and greatly accelerate the wear of hydraulic seals; on the other hand, the abrasive chips generated by normal wear of hydraulic pumps and hydraulic valves, etc. will also accelerate the pollution of the emulsion, and the emulsion containing solid particles of pollutants similar to abrasive for grinding the machined surface of metal parts, resulting in premature wear of hydraulic seals and reducing their sealing role.

3. unreasonable installation of seals caused by leakage

Column jack in the installation process, cylinder head, guide sleeve, piston rod, piston, cylinder installation parts are not clean, machining process generated during the iron chips, burrs and other foreign objects left in the installation parts, in the seals are not coated with smoothing agent, the need to deform the installation of the seals do not apply the appropriate installation tools, may cause the seal leakage.

B. the hydraulic support design and manufacturing reasons

 

Hydraulic support column jack is the main load-bearing and height-adjusting equipment, in addition to a high load-bearing capacity, should also have a large effective stroke.

 

Hydraulic support to the heavy and large development of the column jack length, bore, seal type and other aspects put forward higher requirements, requiring a more reasonable structural design. The groove structure design is not reasonable, mechanical processing accuracy is not high, the choice of seal ring is not reasonable, will cause the column jack leakage .

The physical properties of the material, mechanical properties below the design requirements, no heat treatment of the material or treatment does not meet the requirements, welding is not standardized, the machining accuracy of the parts, roughness is not enough, will also cause a decline in sealing performance, thus causing leakage.

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