|
| >Main structure of the mechanical
seals |
 |
Flexible
member
Face (Primary
Ring)
Metal Parts
Seat (Stationary
Ring)
Springs
|
 The
mechanical seasl shown in above is a simple light-duty design.
The sealing interface where the seal rotating and stationary faces
make rotational contact is a plane annulus. The sealing faces themselves
are lapped to a very high degree of flatness, measured in wavelengths
of light. The body of the rotating component of the mechanical
seal is free to float axially. This enables hydraulic pressure
to keep the main sealing faces together in operation; in the absence
of hydraulic pressure the spring serves the same purpose
The closing force on the seal is designed to provide
an acceptable compromise between leakage and wear. It must also be sufficient
to prevent the faces from separating in the event of mechanical shock or a pressure
fluctuation. A secondary seal prevents leakage between the floating assembly
and the shaft; often a rubber `O' ring is used for this purpose.
| Weak Spring Load |
 |
| Result = Unacceptable Leakage |
|
| Excessive Spring Load |
 |
| Result = Unacceptable Seal Life |
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