How to solve seal leakage in multi-stage centrifugal pumps?
Thread Content
When a seal leakage is detected on one end, replace it； After the replacement, the seal on the other end is leaking – how should this be dealt with?
Check the dimensions before and after sealing each end – the sealing installation dimensions and the dimensions of the pump chamber (relative to the shaft shoulder)! Also, you can check the form and position tolerances!
There’s no doubt – rework is needed to reinstall the seal
Reply to 1# gw821022: Could you send a picture of the mechanical seal for a multi-stage pump? Which company’s product is it?
This is an inevitable issue during maintenance; there are problems due to a lack of careful attention, and it’s certain that the pump in question has shaft displacement.
You didn’t adjust the compression amount properly during installation. When installing, place the shaft in the middle position; when installing both ends together, first determine the total movement of the shaft and then set it in the middle position. The compression amount should be set to a value that is even
If a non-precision end seal is installed on a multi-stage pump, the rotor generally does not shift, and this does not affect the seal at the other end. However, if a positioning end seal is replaced, the positioning bearing has to be removed and reinstalled, which can pull on the rotor; if not done carefully, it may damage the other end seal. It is recommended that when replacing the positioning end seal of a multi-stage pump, first loosen the gland screws of the non-positioning end seal, remove the flange, and create a certain gap between the stationary and rotating rings.
When replacing components, special attention should be paid to the gap between the mechanical seals at both ends; if the gap is too small, the spring pressure will not be sufficient. It is also important to check whether the shaft is worn, as this can affect the fit between the moving and stationary surfaces of the mechanical seals