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Several major factors affecting the sealing performance

Jul. 15, 2019


Several major factors affecting the sealing performance shared by Connector Cavity Plug Supplier.

1. Speed

When the motion speed is very low (< 0.03m/s), the smoothness of the operation of the equipment and whether there is "crawling" phenomenon should be considered. When the movement speed is very high (>, 0.8m/s), the lubricating oil film may be damaged, and the seal may be heated due to friction due to poor lubrication, resulting in a greatly reduced service life.

It is recommended that polyurethane or rubber seal should work within the speed range of 0.03m/s ~ 0.8m/s.

2. The temperature

Low temperature will make polyurethane or rubber seal elasticity reduced, resulting in leakage, and even the whole seal becomes hard and brittle. High temperature will make the oil seal volume expansion, soft, resulting in rapid increase in the friction resistance and pressure resistance capacity. It is suggested that the continuous operating temperature range of polyurethane or rubber seal is -10℃ ~ +80℃.

3. Work stress

The seal has a zui minimum service pressure requirement. Low pressure work must choose low friction performance, starting resistance small seals. Below 2.5mpa, polyurethane seals are not suitable; High pressure to consider the pressure deformation of seals, need to prevent extrusion ring, groove processing also has special requirements.

In addition, different materials of seals have different zui good working pressure range. For polyurethane seals, the working pressure range of zui jia is 2.5 ~ 31.5MPa.

The influence of temperature and pressure on the sealing performance is interrelated, so it should be considered comprehensively. See table:

Imported polyurethane PU material

Maximum working pressure

Maximum temperature range

The velocity is -25 ~ +80 ~ 25 ~ +110

0.5 m/s 28 mpa 25 mpa

0.15 m/s 40 mpa 35 mpa

Connector Cavity Plug Supplier

4. Working medium

In addition to selecting working media strictly according to the manufacturer's recommendations, it is essential to keep working media clean. The aging or contamination of oil will not only make the components in the system malfunction, accelerate the aging and wear of seals, but also the dirt in the system may scratch or embed in the seals, making the seals invalid. Therefore, it is necessary to check the oil quality and cleanliness regularly, and replace the oil filter or oil according to the maintenance specifications of the equipment. The residual air in the oil cylinder after high pressure compression will produce high temperature oil seal burning, even carbonization. In order to avoid this situation, the initial operation of the hydraulic system, should be exhaust treatment. The hydraulic cylinder should also run at a low pressure and slow speed for several minutes to confirm that the residual air in the oil has been discharged before it can work normally.

5. Lateral load

The supporting ring must be installed on the piston to ensure that the cylinder can bear larger load. The sealing element and the supporting ring have completely different functions, and the sealing element cannot replace the supporting ring load. The hydraulic cylinder with lateral force must be equipped with support ring with strong bearing capacity (metal ring can be used for heavy load) to prevent leakage and abnormal wear caused by eccentric working of sealing element.

6. Hydraulic shock

There are many factors that produce hydraulic impact, such as the moment when the bucket of an excavator suddenly hits a stone, or when the crane lifts or drops heavy objects. Except in the factor, for high pressure large flow hydraulic system, the executive element (hydraulic cylinder or hydraulic motor, etc.) when reversing, if the performance of the reversing valve is not very good, it is easy to produce hydraulic impact. The instantaneous high pressure produced by hydraulic shock may be several times the working pressure of the system, which in a very short time will tear the oil seal or partially squeeze it into the gap, causing serious damage. The general hydraulic impact of the cylinder should be installed on the piston rod buffer ring and baffle ring. The buffer ring is mounted in front of the oil seal to absorb most of the impact pressure, and the retaining ring prevents the oil seal from squeezing into the gap under high pressure and causing the root to be bitten.

That's all for the sharing, thanks for your reading, and we also supply connector Cavity terminal plug for sale, if you have any demand for our products, just feel free to contact us.

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