What is “Slurry” and why does it take a special pump to handle it?

Sep 11, 2012   //   by main_admin   //   Business  //  1 Comment

The word “slurry” is used to describe a liquid with solids in suspension. This can be as light as chocolate milk (cocoa particles suspended in milk), or as heavy as concrete (sand, rocks, crushed limestone in water).

Pumps that are designed to handle slurries must be able to counteract the effect that solids in the material have on the equipment and systems in which they are used. If the solids are abrasive (think sand or crushed rock), the pumps must be constructed of materials that will resist the erosion that comes as a result of the impact of those particles have as they come into contact with the pump casing and impeller. Special hardened metal alloys, elastomer liners, or combinations of both are commonly used to effectively control these forces. The impellers are designed with wider vanes to handle over sized materials that are commonly found in processes such as hard rock mining, dredging, or pulp and paper.

Selection of pumps to handle slurries with settling solids must take into consideration the size, density, shape, and concentration of the solids along with the temperature and viscosity of the liquid in the mixture. If you take a gallon of water and add a cup of dry sand to it, the sand particles will quickly settle to the bottom of the container. If you are pumping a slurry containing sand, the material must maintain a velocity within the pump and the piping to maintain the particles in suspension or the pipe will quickly become clogged. Therefore, the heavier the solids—the faster they will settle and the higher the velocity required to keep the solids in solution.

These are just a couple of the details that are taken into consideration when selecting a slurry pump. Similar to the difference in jogging on pavement vs jogging on the beach, the effects of solids require special considerations and designs to counteract the changes brought about by the materials being pumped.

1 Comment

  • In addition to wear and impact resistant wet end materials, slurry pumps have robust mechanical ends, The shafts and bearings are much larger than found on similar sized water pumps.

    GIW pumps do not require back side clearing vanes to reduce thrust loads. Bearing are sized to handle common loads. Back side clearing vanes on impellers do have their place for expeller/dynamic seals but with high concentrations, these back side vanes can increase wear on the back side of the pump casing.

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