Sealing mechanism and seal life
The function of oil seal is to prevent mixing of two fluids each other, or to prevent oil leakage mostly for a rotating motion and rarely for reciprocating motion.
The sealing mechanism is subject to various factors including seal profile, material, rotating surface, revolution speed, medium temperature and pressure, vibration, eccentricity, out of roundness and axial movement of the shaft.
Sealing mechanism consists of mainly two functions:
1) Static Sealing: Sealing between bore and outer surface of seal,
2) Dynamic Sealing: Sealing by lip on the shaft. Functions are shown below.
Figure 5
1) Static Sealing:
The outer surface of the radial shaft seal, has the task of making a static seal between the surface and the housing bore.
2) Dynamic Sealing:
The function of sealing lip is to provide a sealing at the at the contact line of the sealing edge on the rotating shaft surface. Insufficient or excessive radial force, the sealing applies on the shaft, will effect the sealing mechanism ability.
Figure 6: Sealing lip fitness
Figure 7: Power consumption versus shaft diameter
The sealing torque and power consumption increase as shaft size and rotational speed increases. In no circumstances must the sealing lip be run dry. For this reason greasing or oiling of both seal and shaft must be done prior to installation to assure sealing lip lubrication during the very shaft rotations.
Figure 8: Shell life of various rubber elastemers with respect to temperature
Elastomers when exposed to heat tend to harden and become brittle, the longer the exposure or the higher the temperature, the greater the ageing effects. Temperature/Shell-Life characteristics of a range of elastomers are in above figure.
Factors effecting sealing lip temperature:
Oil temperature
Mechanical factors
Excessive radial load
Sealing elements
-
Sealing mechanism and seal life
About SKT
References
Vendors
Materials
Storing the parts
Catalog
Sealing elements
Rotary shaft seals
Water pump seals
Valve stem seals
Brake systems
Shock absorber seals
Hydrolic seals
O-Rings
Plugs
Bushing and mounts
Various products
Seal kits
Repair kits
PTFE Parts
Iron Sheet Parts
Important information
New product form
Query
List of parts
List of where-used
