Seals are materials or parts that prevent fluid or solid particles from leaking from adjacent joints and external impurities such as dust and moisture from intruding into the internal parts of machinery and equipment.
Use classification
Classified by function: divided into shaft seal, hole seal, dust seal, guide ring, fixed seal, rotary seal;
Classified by material: divided into nitrile rubber, EPDM rubber, fluorine rubber, silica gel, fluorosilicone rubber, nylon, polyurethane, engineering plastics, etc.
Storage
The storage temperature of the seal is preferably below 30 °C to avoid high temperature aging of the seal;
The seal must be stored in a sealed package to avoid contact with moisture or dust in the air;
The seal must be protected from strong light to prevent the seal from being eroded or premature by ozone in the air.
The factors affecting the performance of various seals are different. For example, mechanical seals (filler seals, etc.) have factors such as temperature, medium, wear and pressure.
Use points
(1) Select the appropriate seal material and hydraulic oil, as well as adaptability to working temperature and oil compatibility.
(2) The geometric position accuracy (concentricity) of the sliding parts relative to the seal is high (such as hard chrome plating) and the surface roughness is fine to prolong the service life.
1 For the hydraulic pump and the motor journal, the oil seal not only requires the roughness of the sliding surface to be within 0.25m of Ra, but also requires hard chrome plating on the surface. In the specific use, it is necessary to adjust the diameter of the lip of the oil seal according to the specific conditions. The spring force is applied to make it elastic, and a sealing sleeve or a thin gasket is used to protect the sealing ring during installation, so as to prevent the lip from rolling and twisting, causing the spring to slip out.
2 The inner surface of the hydraulic cylinder is usually processed by rolling, which not only improves the surface roughness, but also makes the surface cold-hardened, which is beneficial to prolong the service life of the sealing ring. In addition, the pressure used, the length and type of the sliding surface have a great influence on the service life. Therefore, the “check” time should be determined based on these conditions.
3 It is required that the sealing surface is in a good lubrication state and prevents intrusion of dirt. It is also a necessary condition to use the oil that meets the specified cleaning level and the correct installation method.
