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Impeller Clearance Adjustment For Slurry Pumps

The following procedure describes impeller clearance adjustment for slurry pumps with gland packing seal.

1, Stop the pump, loosen clamp bolt of bearing housing.

Loosening bearing assembly may damage the mechanical seal, so when slurry pump are fitted with mechanical seals, loosen only the clamp bolt near to the impeller.

The rise at bearing assembly drive end should be less than 0.25mm.

2, Rotate the shaft according to direction of rotation by hand and move the bearing assembly forward by tightening the adjusting screw until the impeller rubs on the front liner.

3, Release the nut that is just tightened by 1/3 turn, then move the bearing assembly back by tightening the front nut on the adjusting screw.

4, Tighten clamp bolts and adjusting screw nuts to secure the bearing assembly in position.

5, Ensure that the impeller does not contact with the front liner as rotating the shaft. If contact occurs, repeat step 3 and 4.

Note: After each impeller adjustment is completed, the bearing housing clamp bolts and adjusting screw nuts must be tightened.

With centrifugal expeller seal assembly fitted, the slurry pump impeller forward adjustment may increase shaft seal pressure, if leakage occurs, the impeller should be adjusted backward to solve the leakage.

Leakage may be solved by changing a different impeller which have improved expelling vanes on the back and front shrouds.

Any problems please feel free to contact us.

The impeller clearance adjustment is an important factor in maximizing wear life of both impeller and liners. Experience has shown that an increase in wear life of up to 20 – 50 percent can be achieved by regular slurry pump impeller adjustment, compared with slurry pump no adjustment of impeller clearance over its operating life.

Both rubber and metal lined slurry pumps with gland packing seal should drive impeller having minimum axial clearance with throat bush or cover plate liner, this is the most important thing while using high efficiency impellers.