How to distinguish between mechanical seals and hydraulic seals

Mechanical seals generally have no pressure requirements. They are metal hard seals. The liquid to be sealed is sealed by the rotation between several seals. The hydraulic seal has pressure requirements, and the joint surface is required to have a certain degree of smoothness. The sealing components are mostly made of rubber and pass through the seals. The local deformation achieves a closed effect.

Mechanical seals are static seals, such as sunken roll seals. Hydraulics are generally reciprocating seals, such as Y-rings, SPGW

The general mechanical seals are made of metal outside, and the hydraulic seals are now mainly made of PU and polyurethane, which is easy to distinguish!