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Introduction to several major factors affecting sealing performance

Speed of movement
When the movement speed is very low (<0.03m/s), it is necessary to consider the smoothness of the equipment operation and whether there is a "crawling" phenomenon. When the moving speed is high (>0.8m/s), the lubricating oil film may be destroyed, the oil seal is not well lubricated and the friction is heated, resulting in a greatly reduced life.
It is recommended that the polyurethane or rubber-plastic seal be operated in the range of 0.03m/s to 0.8m/s.
2. Temperature
Low temperatures can reduce the elasticity of polyurethane or rubber and plastic seals, causing leakage, and even the entire oil seal becomes hard and brittle. The high temperature causes the oil seal to expand and soften, causing a rapid increase in the frictional resistance of the oil seal during operation and a decrease in pressure resistance. It is recommended that the polyurethane or rubber and plastic oil seals have a continuous operating temperature range of -10 °C to +80 °C.
3. Work pressure
The oil seal has a minimum service pressure requirement. For low-pressure work, oil seals with low friction performance and low starting resistance must be used. Below 2.5MPa, the polyurethane oil seal is not suitable; when the high pressure is taken into account, the oil seal is subject to compression deformation, and the anti-extrusion retaining ring is required, and the groove processing also has special requirements.
In addition, oil seals of different materials have different optimal working pressure ranges. The optimum working pressure range for the polyurethane seal is 2.5 to 31.5 MPa.
The effects of temperature and pressure on the sealing performance are interrelated, so comprehensive considerations are needed. Seals
4. Working medium
In addition to selecting the working medium in strict accordance with the manufacturer's recommendations, it is important to keep the working medium clean. The aging or contamination of the oil not only causes failure of the components in the system, but also accelerates the aging and wear of the oil seal, and the dirt therein may be scratched or embedded in the oil seal to invalidate the seal. Therefore, the quality of the oil and its cleanliness must be checked regularly and the oil filter or oil should be replaced according to the maintenance specifications of the equipment. The air remaining in the oil in the cylinder is compressed by high pressure to generate high temperature, which causes the oil seal to burn out and even carbonize. To avoid this, exhaust gas treatment should be performed at the beginning of the hydraulic system operation. The hydraulic cylinder should also run at low speed and slow for a few minutes to confirm that the air remaining in the oil has been drained before it can work normally. Seals

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