Mechanical Seals
Mechanical Seals
(OP)
We have positive displacement pumps which use mechanical seals which are designed for a Max. Inlet pressure of 3.5bar.
It has been noticed that although we can maintain the 3.5bar during normal running conditions, the thermal relief valves on the inlet piping are set at 5.5bar
Does this mean the seals will leak or is the situation different when the seals are not rotating?
Regards
Paul
It has been noticed that although we can maintain the 3.5bar during normal running conditions, the thermal relief valves on the inlet piping are set at 5.5bar
Does this mean the seals will leak or is the situation different when the seals are not rotating?
Regards
Paul





RE: Mechanical Seals
RE: Mechanical Seals
RE: Mechanical Seals
I have noticed that the pump stuffing box is already linked to the pump inlet
Regards
Paul
RE: Mechanical Seals
Is this a sliding vane or gear pump, or something else?
The tubing you describe not only helps to lower the pressure in the seal chamber but to induce flow around the seal to help remove the heat it generates.
RE: Mechanical Seals
Are you sure the piping arrangement is not an internal relief line?
The problem with running an unbalanced seal at higher pressures is also that it generates more heat at higher pressures because not only do you have spring force pressing the faces together but you also have suction pressure adding to that which will increase the friction (e.g. heat) at the seal faces. This will lead to shorter seal life.
Tim S.
RE: Mechanical Seals
I would ask the seal vendor for his advice, but I would guess that at these pressures there is a fairly good chance that the seal will hold when stationary.