Hyd cylinder seals commonly use self-sealing compression type hydraulic seals, which are mainly O-ring, round sealing ring, rectangular ring, etc. They have a simple structure, are easy to manufacture, are low cost, and have other advantages, so they are widely used in hydraulic transmission systems of dynamic and static seals. They are installed in the sealing groove, which usually produces 15 ~ 25% of the radial compression deformation, and the sealing surface has a high initial contact stress to prevent the leakage of non-pressurized liquid.
Selecting Hydraulic Seals
When purchasing maintenance seals, like piston Seals, rod Seals, shaft lip seals, wiper Seals, etc., most users will go by the size and color of the sample, which will only increase the difficulty of purchasing, and they may not always be able to choose the right product. It is recommended that the following procedures be used to improve the accuracy of seal purchasing:
- Direction of motion
Determine the direction of motion where the seal is located, such as reciprocating, rotating, spiral, or fixed.
- Seal focus
For example, decide whether the point of movement is in the inner diameter of the tie rod seal or the end of movement is in the outer diameter of the piston seal.
- Temperature rating
Check the operating temperature from the original machine instructions or evaluate the operating temperature according to the actual working environment to decide the required material. For the temperature rating, please refer to the following notes for manufacturing users.
- Pressure Rating
Check the relevant data from the original machine instructions or deduce the working pressure level by observing the hardness and structure of the original seals. For the description of the pressure level, please refer to the following precautions for production users.
Most users will be used according to the old sample selection. Still, the seals, after some time, will be temperature, pressure wear, and other factors significantly affect the original size; according to the sample selection can only be used as a reference; a better way is to measure the seal location of the metal groove size, the accuracy will be higher.
Note To Users
The general cause of damage to the seals, but also almost the work requirements of the seals:
1. Hardening (aging)
One of the causes of the leakage of seals is that the effects of temperature harden the material itself. When the hardness is too high, the seal cannot fill the gap between the seal and the mating parts, and leakage will occur.
2. Wear and tear
The seals’ wear involves the mating parts’ surface finish, movement speed, transmission media, etc. Different sealing materials are adapted to different movement speeds.
When the seal is subjected to excessive pressure, it will be extruded into the metal gap, causing damage to the seals and leakage. This situation involves the hardness of the seal itself and the metal gap being too large. If, in the design, selection, processing, or installation of improper handling, there will be extrusion damage.
The situation is manifested in the seal softening or even dissolution because the seal is invaded by the media and the selection of materials when the error occurs. If the press contains water or solvents, you should pay special attention.