Types and introduction of hydraulic seals - static seals

1. Hydraulic seal O-ring

The seal with a circular cross-section can achieve sealing by eliminating the gap by pre-compression, and can automatically increase the contact stress between the seal and the sealing surface as the pressure increases, thereby improving the sealing effect. It can be used for static sealing of high-pressure end faces and cylindrical surfaces, and can also be used for low-pressure reciprocating dynamic sealing of low-pressure moving speed. Inexpensive, simple, good sealing, automatic compensation after wear and tear.

2. Various sealing gaskets for hydraulic sealing

Combined sealing gasket is a combined sealing gasket made of oil-resistant rubber inner ring and steel outer ring, which is easy to install and reliable in sealing. It is mostly used for end face sealing of threaded pipe joints, etc.

3. Sealant for hydraulic seals

The sealant has fluidity and can fill the gap between the two joint surfaces, and it can seal and prevent leakage under a certain tightening force. According to the nature of the film formed between the two bonding surfaces, it can be divided into four types: dry adhesion type, dry peelable type, non-dry sticky type and semi-dry viscoelastic type. It is divided into two categories: liquid sealant and anaerobic sealant.

After dry peelable coating, the solvent volatilizes quickly to form an elastic film, which is easy to peel off from the adhesive. It has good vibration resistance, but it is easy to volatilize and is difficult to use on a large area.

The non-drying sticky sealant does not dry for a long time after application, and always maintains viscoelasticity. Therefore, it has good detachability, high vibration resistance and impact resistance, and is suitable for large-area coating.

The semi-dry viscoelastic type is between the above two and has the advantages of both.

Anaerobic sealants are suitable for pressure-resistant sealing of some small surfaces such as threaded pipe joints, which can prevent impact loosening and leak-proof.

The application method of liquid sealant and anaerobic sealant is: pretreatment (remove oil, rust, decontamination) → coating (coating 0.06-0.1mm) → drying → fastening.