For slurry pumps, impellers are manufactured in hard metal white irons or metal reinforced elastomers. The optimum pump speed, or speed range, can be achieved by suitable means, for example, v-belt drive or variable speed drives, to meet the duty requirements. Drive/installation mode of slurry pump: v-belt drive (CR, CL, CV, ZV, ZL, ZR), flexible coupled drive (DC), direct variable speed drive, etc.
Slurry Pump impeller diameters (hard metal or elastomers) cannot easily be altered, so a speed change is necessary as to change pump performance. This is normally done with a V-belt drive. By changing one or both pulleys, the pump can be slightly adjusted to achieve the duty point.
If the belts are tensioned correctly, modern V-belt drives are extremely reliable with a life expectancy of 40,000 hours and a power loss of less than 2%. Typical max. speed ratio for V-belt drives is 5:1 with 1500 rpm motors and 4:1 with 1800 rpm motors.
For duties up to approximately 400hp, V-belt drives from a fixed-speed motor are commonly employed. Where frequent variations are required, this solution is unattractive because the pump must be stopped to change speed and the speed changes are stepped.
Flexible coupled drive is a kind of direct drive for slurry pump. The shafts of motor and pump are in the same line with a flexible coupling. There is a flexible ring in the coupling which has buffering and damping functions. The shafts do not need strict centering during installation.
are always used in the submersible pumps and where application dictates on horizontal and vertical pumps. The motor and pump are coupled with a shaft or a coupling. For certain applications, (varying flow conditions, long pipe lines, etc.) direct variable speed drives should be used.
With variable speed drives, the flow of a slurry pump can be closely controlled by tying the speed to a flow meter. Changes in concentration or particle size then have a minimal effect on flow rate. If a pipe line start to block, the speed will increase to keep flow velocity constant and help prevent blockage.
Modern electronic drives, particularly variable speed drives have many advantages (can be used with standard motors) and are widely used.
Flexible coupled drive and V-belt drive should be preferred applied as the prices are cheaper and the dismountings are easy. Working range of slurry pump is commonly changed by adjusting rev., while difference exists between rev. of slurry pump and motor, V-belt drive and direct variable speed drive can be used to change pump rev. to meet the requirement. V-belt drive is easier, but the required space is larger. If the head range is wider, V-belt drive should be combined with variable speed drive.