P.V. Factor

The pressure/ velocity factor is an attempt to correlate the relationship between the pressure and the velocity at the mechanical seal faces. Unfortunately carbon graphite is sensitive to “P”, but not to “V” so the correlation does not work too well when you talk about mechanical seals. However, this small point does not stop many seal companies from constructing a set of PV limits for various seal face combinations.

I once worked for a seal company that set the seal face PV limit by attaching one of the faces to a drill press and then running it against the mating face, under water, at various loads until it became obvious that the load was too much.

I guess it is as good a system as any, but unfortunately we are not always sealing fresh water. To do the job properly you would have to create a table of various face combinations, different loads, and multiple fluids…. good luck!



  • On February 16, 2018