|Can the seal be rebuilt?
One of the mysteries associated with pump seal repair is "When is my mechanical
seal suitable for repair?" Often times the seal looks good to the naked eye, but when
it gets to a repair center the comment comes back "This seal is non-repairable."
How do you know if your pump seal is repairable or not? Obvious catastrophic damage
to the seal such as a broken sleeve or an extremely eroded gland would indicate that you
may have significant problems that would prevent a repair. If you have more pieces of the
seal come out of the pump than went in would indicate a non-repairable situation. The best
thing to do is have a trained pump seal specialist evaluate the seal. Even a seal
that looks hopeless externally can sometimes be brought back to new condition for
relatively little money.
All pump seals function basically the same way. Two
mating faces contact each other forming a seal at the mating surface. Usually one surface
is made of a soft material such as carbon and the other surface is made from a hard
material such as silicon carbide. A series of O-rings or other sealing materials form
seals on the shaft and gland area. Everything is held in the stuffing box by a gland of
some sort. Depending on the design of the pump seal, everything may be mounted on a
sleeve and cartridge mounted to incorporate the gland into the seal itself.
|What is involved in a proper rebuild
The most important thing to do first is choose a company that has a good reputation for
quality repairs and ethical business practices. There are many companies today that claim
to bring seals "up to the original equipment manufacturer's standards," but they
use inferior materials that result in shorter product life and in some cases, cause
serious damage to the pumping equipment. Research carefully the facility doing the repairs
to ensure that it has the latest manufacturing and testing equipment. On-site engineering
capabilities and tools, such as finite element analysis, lead to better overall repair
companies. If the company you choose is sending the seal components to outside sources to
be refurbished, audit the sources to ensure you are getting a quality repair.
best source for repairs is a company that does everything in-house including
manufacturing, assembly, and testing. This ensure that you have product integrity
throughout the process.
The first step in repairing any pump seal is documenting the seal properly--where
it came from, the service it is in, and any other comments that may have come from the
user company. The next step is to disassemble and clean the seal completely for inspection.
After the seal has been inspected a list of components necessary for rebuild can be