How Slurry Pumps Differ From Standard Pumps?
Pumping mud is not as easy as pumping water. Depending on the type of slurry, there are many variables in choosing the right pump for the slurry. There is no formula or set-in-stone answer as to what the best slurry pump design is. You must combine knowledge and application details to select the ideal slurry pump. Let's talk about how slurry pumps differ from standard pumps and how to narrow your choices.
What is slurry?
First, what is a slurry? A slurry is a semi-liquid mixture, usually consisting of fine particles. Examples of slurries can include manure, cement, starch, or coal suspended in water. There are countless other combinations that can be considered "slurries". Because of the added particles and thicker consistency, special pump requirements should be considered. A standard pump may be able to handle the fluid, but not as effectively as a properly sized slurry pump.
Consider the impeller. Slurry pumps must have thicker vanes than water pumps to prevent wear. Due to the increased thickness, there will be fewer vanes, otherwise the passages will be too narrow and will affect the performance of the pump. The impeller should have a large enough passage so that the largest solid particles can pass through without clogging.
Another important part of the slurry pump is its casing, which bears all the pressure. The slurry pump casing should have a large clearance between the impeller and the diversion angle to reduce wear and prevent large solid particles from getting stuck. Due to the extra space, there is more recirculation in the slurry pump casing under various operating conditions. Again, this accelerates wear compared to typical pumps.
Materials of Construction
Metal and/or rubber pump bushings are used to combat the erosion of solid particles found in the slurry. Metal slurry pump housings are usually made of carbide to resist erosion caused by increased pressure and circulation. Sometimes wear-resistant steel is used on the pump casing so that the pump can be welded if repairs are needed.
Keep in mind that slurry pumps are designed to adapt to specific pumping conditions. Pumps used in the cement industry handle most fine particles at low pressures, so the casing can be of lightweight construction. In rock pumping, the casing and impeller must be able to resist slamming, so they must be built thick and strong.
Slurry pumps can also simply axially adjust the clearance between the impeller and the adjacent throat casing sealing surface. This helps to maintain pump performance when internal components begin to wear.