Choose hydraulic cylinder seals
Oct 05, 2021
Compression-type seals commonly used in hydraulic seals are mainly O-rings, round seals, and rectangular rings. They have the advantages of simple structure, easy manufacturing, and low cost. Therefore, they are widely used dynamic seals in hydraulic transmission systems. Components and static sealing components.
The specifications of hydraulic seals installed in the seal groove usually produce 15~25% radial compression deformation, and produce high initial contact stress on the sealing surface, thereby preventing the leakage of pressureless liquid.
When the hydraulic cylinder is working, the pressure liquid squeezes the self-sealing compression hydraulic seal to further deform it, and produces a greater pressure of the pressure liquid on the surface of the seal specification, which should be strictly the pressure. The increased and increased additional contact stress, together with the initial contact stress, prevents the leakage of the pressure liquid.
When the standard working pressure of hydraulic cylinder seals is greater than 10MPA, in order to avoid a part of the synthetic rubber self-sealing compression hydraulic seal being squeezed into the sealing gap and being cut off during the reciprocating movement of the hydraulic cylinder, it must be leaked. A synthetic resin retaining ring, such as a nylon back up ring, a POM back up ring and a filled PTFE back up ring, is provided on the pressure side of the self-sealing compression hydraulic seal.
Therefore, when purchasing seals for maintenance, most customers will buy them according to the size and color of the sample, which will only increase the difficulty of purchasing, and it may not be possible to select the right product. DSH Seals recommends the following methods to improve the accuracy of the procurement of seals:
1. Movement direction: First determine the movement direction of the location of the seal, such as reciprocating, rotating, spiral or fixed.
2. Sealing key points: For example, it is determined whether the active point is the tie rod seal with the inner diameter or the piston seal with the outer diameter.
3. Temperature grade: consult the original machinery operating instructions or evaluate the working temperature according to the actual working environment to determine the required materials. For the description of the temperature level, please refer to the following notes for production users.
4. Pressure level: refer to the relevant data from the original mechanical instructions, or infer the working pressure level by observing the hardness and structure of the original seal. For the description of the pressure level, please refer to the following notes for production users.
5. Size: Most users will buy according to the used old samples, but after a period of use, the original size of the seal will be greatly affected by factors such as temperature, pressure and wear. The selection according to the sample can only be used as a reference , A better method is to measure the size of the metal groove where the seal is located, the accuracy will be higher.
