Slurry pump maintenance
For long trouble-free service with a minimum amount of maintenance it must pay much attention to following items.
5.1 Shaft Seal Care
In gland sealed pump periodically check gland seal water supply and pressure. Always maintain a small amount of clean water leakage along the shaft by regularly adjusting the gland. When gland adjustment is no longer possible replace full packing. Quantity and pressure of sealing water should be correspondence with the above mentioned requirements.
In centrifugal sealed pump lubricate the packing and lip ring regularly by means of the grease cup.
5.2 Impeller Adjustment
Pump performance changes inversely with the clearance existing between an impeller and the intake-side liner. For the pump high efficiency operation the clearance between the impeller and liner must be adjusted. In metal pump the clearance between an impeller and the frame plate liner should be in 0.5-1mm. In rubber liner pump the clearance between an impeller and front & back liner should be equal. Firstly stop the pump when adjusting the clearance.
Rotate shaft clockwise by hand and move bearing assembly forwards by tightening rear nut until the impeller starts to rub on front liner. For metal lined pumps, release the nut just tightened by half a turn, then move bearing assembly back by means of front nut until housing lug touches rear nut and the clearance will be in 0.5-1mm. For rubber lined pumps, release fully rear nut, rotate shaft clockwise by hand and move bearing assembly back by means of front nut until impeller starts to the back of the end cover. Calculate the average distance and adjust the bearing assembly forward to this distance to be sure of the correct clearance between impeller and front and back liner. After adjustment, check the impeller rotation again and tighten clamp bolts and both adjust screw nuts before starting up the pump. Then start up the pump.
5.3 Bearing Lubrication
A correctly assembled and pre-greased bearing assembly as well as adequate maintenance will have a long trouble-free life. Maintenance personal should open the bearing housings at regular intervals (not longer than twelve months) to inspect bearing and grease. The frequency and amount of lubricant to be added periodically depends upon a number of factors and a combination of them, including speed and size of bearing, duration and extent on-off operation, and the usual environmental condition such as ambient and operating temperature and so on. Bearing heating will be caused by over-lubricating. Therefore, adjustment and experience should be the final determining factors in establishing routine lubrication procedures. Following table can be referred to lubricate adequately.
5.4 Spare pumps should be turned in a quarter of turn so that the bearing may support static load and vibration from outside evenly.
Note: Above-mentioned is only suitable for the normal operating condition and intended to be a guideline.
Above-mentioned lubricants are used for bearing. For the bearing assemblies plugs inside bearing assembly are used for adding lubricant into the bearings and grease cup outside for cleaning labyrinths.