Views: 2454 Author: Site Editor Publish Time: 2020-07-10 Origin: Site
In the hydraulic system and its system, the sealing device is used to prevent the leakage of working medium and the intrusion of external dust and foreign objects. The element that plays a role in sealing is the seal accessories. Leakage will cause waste of working medium, pollute the machine and environment, and even cause malfunction of the machine operation and personal accident of the equipment. Therefore, seals and sealing devices are an important part of hydraulic equipment. Its working reliability and service life are an important indicator for measuring the quality of the hydraulic system. So what are the factors that affect the hydraulic seal?
When the movement speed is very low (<0.03m / s), it is necessary to consider the stability of the equipment operation and whether there is a creeping phenomenon. When the movement speed is very high (> 0.8m / s), the oil film that plays the role of lubrication may be damaged, and the oil seal will not be well lubricated which will generate friction and heat, resulting in a greatly reduced life. It is recommended that polyurethane or rubber-plastic oil seals work in the speed range of 0.03m / s ~ 0.8m / s.
Low temperature will reduce the elasticity of the polyurethane or rubber-plastic oil seal, which will cause leakage and even the entire oil seal becomes hard and brittle. High temperature will cause the volume of the oil seal to expand and become soft, causing the friction resistance of the oil seal to increase rapidly and the pressure resistance to decrease during exercise. It is recommended that the continuous operating temperature range of polyurethane or rubber-plastic oil seal is -10C ~ + 80C.
The oil seal has a minimum starting pressure which is required by minimum service pressurs. Low-pressure operation must use an oil seal with low friction performance and low starting resistance. Below 2.5MPa, the polyurethane oil seal is not suitable; when high pressure, the pressure deformation of the oil seal should be considered. With anti-extrusion retaining rings, groove processing also has special requirements.
In addition, oil seals of different materials have different optimal working pressure ranges. The best working pressure range for polyurethane oil seal is 2.5 ~ 31.5MPa. The effects of temperature and pressure on the mechanic seals performance are interrelated, so comprehensive consideration is required.
In addition to strictly selecting the working medium in accordance with the manufacturer's recommendations, it is essential to keep the working medium clean. The aging or pollution of the oil will not only cause the components in the system to fail, accelerate the aging and wear of the oil seal, but also the dirt in it may scratch or be embedded in the oil seal, making the seal invalid. Therefore, the quality and cleanliness of the oil must be checked regularly, and the oil filter or oil must be replaced according to the maintenance specifications of the equipment. The air remaining in the oil is compressed by high pressure, which will produce high temperature and cause the oil seal to burn out and even carbonize. To prevent this from happening, exhaust treatment should be performed at the initial operation of the hydraulic system. The hydraulic cylinder should also run at low pressure and slow speed for several minutes to confirm that the air remaining in the oil has been exhausted before it can work normally.
We hope the information will help you know more about hydraulic seal.