For settling slurries and manual calculations, Cave’s correlation is the most common method of allowing for the effects of solids on pump performance. Later methods like the Metso method which include pump size effect are utilized when sizing software's like PumpDim are used. These methods are more accurate and the Cave method is often too conservative.
To obtain a better understanding of the pump sizing process, the inexperienced user is strongly recommended to study the booklet "Slurry Pump Basic" published by Metso Sweden AB. See downloads below.
- Optimized to ensure maximum efficiency
- Ensure safe and reliable operation with maximum time between failure
- V-belt drive selection
- Pipe system sizing
Pump performance with settling slurries
The results from PumpDim are representative for settling slurries with “normal” particle size and distribution, such as those found in mineral processing industries, with concentrations lower than 40% by volume.
The program considers and/or calculates for example the following parameters:
- Critical flow velocity to avoid settling of particles in pipes.
- The complete pipe head loss system curve when static head, pipes, fittings and other components are specified.
- Pumping of froth when a froth factor is specified.
- Effect of solids on the generated pump head and pump efficiency.
- Recommends material for the pump wet end considering particle size and distribution.
- Selects pump size for the specified duty and calculates required pump speed.
- Calculates shaft deflection and bearing life at the duty point.
- Recommends motor size and drive for the duty.
- Calculates slurry density based on particle and liquid density and concentration and/or tonnage. Calculates actual flow through an existing installation based on pipe system, slurry properties and pump speed i.e. determining circulating load in mill discharge applications.
Homogenous slurries with particles essentially smaller than 50 um i.e. clays, cement slurries, coating and filler quality calcium carbonates that have a non-Newtonian behavior, need to be treated as a viscous liquid. The true slurry plastic dynamic viscosity, yield stress and flow index need to be known. These parameters can be established from test work carried out by Metso, or other laboratory.
For particles with a flaky or fibrous shape i.e. some mill scale applications and paper pulp applications need special considerations. Please consult Metso's application specialists.
The program has been developed by Metso and remains our property at all times. It shall be returned upon request. The software is Metso’s copyright and shall not be copied or passed to third parties without our written permission.
Any information gained from the software is advisory only, and implies no legal binding offer or warranty, unless confirmed by Metso. Any questions regarding the software shall be addressed to the local Metso office.
|Slurry pump basic handbook - English||Download|