The Characteristics Of The Use Requirements Of The Combined Seal Products
Apr 11, 2022
Selection of composite seal materials.
There are three requirements for the selection of combined seal materials:
1. The selected materials can meet the physical performance requirements required
physically；
2. The ability to maintain physical properties within the working period of normal
use
3. The material must have wear resistance. Rubber and synthetic rubber are ideal
seal production materials. Most of the materials currently used are mainly synthetic
rubber or leather. The synthetic rubber material has low rigidity, can deform with
the unevenness of the sealing surface to compensate for the sealing, has high
tensile strength and elongation, and has high pressure impact resistance.
The choice of the structure of the combined seal.
The structural form of the combined seal can be selected according to different
working pressures and working environments. But no matter which seal material is
used, it is impossible to meet various performance requirements at the same time.
PTFE is used as the sealing material of the sealing ring, and the rubber O-ring is
used as the elastic pressing force.
Geometry and size of combined seals
The material of the combined seal works for a long time at the working temperature,
which will cause the volume to increase by about 10 to 20 percent. For the design of
the groove size of the V-ring seal, the volume expansion factor of the seal product
during operation is considered. Failure to do so will cause the seals to stick,
resulting in damage due to excessive friction. The fitting clearance of the
installed O-ring should be strictly controlled to prevent extrusion. The geometric
shape and size of the combined seal product itself have a great influence on the
sealing and friction performance of the seal itself, and should be selected or
designed reasonably according to the different working environment conditions.
Improve the surface finish of the sealing surface.
Improving the sealing surface finish can reduce the friction coefficient and improve
the friction conditions. The sealing surface acting on linear motion needs to be
ground; the sealing surface of rotary motion needs to be ground and polished.
Correct installation of combined seals.
Often due to improper assembly, seals have been damaged before work. There should be
a chamfer at the place where the sealing ring is installed to avoid the sharp point
from scratching the seal, and it can also be used as a guide sleeve when installing
the sealing ring. When installing the seal through the thread, use a special
installation tool to protect the seal from scratching the sealing surface during
installation.
