Choosing the right pump for your operation

By |  July 1, 2016

Pumps used in mining applications are subject to the harshest and most demanding conditions on earth. From dewatering to mineral extraction, pumps are required to perform efficiently in difficult conditions and for long hours. It is important to select the most appropriate pumps for each specific application.

There are a number of factors to consider in selecting and configuring pumps. The first step is to define the overall system objectives, considering such things as uptime requirements, maintenance spending targets and energy efficiency requirements.

Once those goals have been established, the process of choosing the best pumps for a mining application can begin.

Start by choosing a pump type that is suitable, given your application and system objectives. Certain pump types are more energy efficient than others, have different physical footprints, require different maintenance frequency, and have different price points.

If more than one pump technology could meet your criteria and you are unsure of the tradeoffs, contact a pump manufacturer or distributor to help with the selection process.

Size and configuration

This illustration shows both lineshaft (left) and submersible (right) turbine pump applications.

This illustration shows both lineshaft (left) and submersible (right) turbine pump applications.

Once a pump type has been selected, it must be sized and configured for the application. To do this, engineers must define the flow rate or volume of water that will pass through the pump per unit in time, based on the requirements of the application.

Then they must determine the static head and friction loss of the system. The static head is the height of a column of water that would be produced at a given pressure.

Calculating the static head identifies the internal energy of a fluid owing to the pressure exerted on it from the pump. Friction loss is the reduction of static head that occurs due to viscous effects generated by the size and surface of the pump and flow path.
Friction loss occurs throughout the entire system and must be accounted for; narrow corners and valves that impede flow create high friction loss.

Many pump manufacturers offer online selection software that takes operating parameters (e.g. flow rate and head) and generate pump configurations with their corresponding Best Efficiency Points (BEP). This enables selection of the most hydraulically efficient pump size based on the system’s requirements.

Online software can also help with Net Positive Suction Head (NPSH), and other selection considerations, such as the environmental conditions the pump will be working in, which determine the best motor enclosure, base plate (where applicable), paint and other options.

For mining applications, it is important to select a pump that is compatible with the media being transported. Some pumps are specifically designed to handle slurries, and may be constructed with hardened metal components or use rubber-lined casings to reduce abrasion.

They can be used to move mixtures of liquid and suspended solids in a broad array of applications such as mine drainage, dredging of settling lagoons, and pumping of drilling mud.

In an industry in which maintaining production, maximizing uptime and minimizing maintenance are the keys to success, keeping the system running is a top priority. By selecting the proper pumps, companies can keep work progressing and costs in line.

 

Nate Maguire is the Americas business unit director, industry and agriculture for Xylem’s applied water systems business unit.


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