Pumping Abrasives
Masterflex® pumps are well suited for pumping abrasive slurries for several reasons. The peristaltic pumping action is gentle on the fluid, reducing tubing wear. The only part of the pump the fluid comes in contact with is a smooth piece of tubing; there are no fittings or valves that particles may clog. Abrasive materials can shorten the life of any pump, but the tubing is quickly and inexpensively replaced.
Follow these suggestions to get the maximum performance from your peristaltic pump:
- Choose abrasion-resistant tubing. Norprene® and PharMed® have good abrasion resistance. Tygon® is fair with abrasives, while silicone, C-FLEX® and Viton® are moderately resistant to wear from abrasive materials.
- Use an adjustable occlusion pump head. The standard occlusion for all Masterflex fixed occlusion pump heads is shown in Figure A. Abrasive materials, especially hard particles, are pressed into the tubing wall and can cause a great amount of wear. Using a variable occlusion pump head allows you to reduce the amount that the tubing is squeezed (Figure A). The result is less wear on the tubing. By increasing the occlusion to prime the tubing and then reducing it to pump, you'll get maximum performance from your pump with the least amount of wear on the tubing.
- Select a larger tubing size. This will reduce the rate that particles come into contact with the tubing wall. Soft particles should have an ID less than 25% of the ID of the tubing. Hard particles should be even smaller in relation to the ID of the tubing (less than 5%). Keeping these ratios will reduce the rate that the tubing is being worn from the inside (Figure B).
- Slow down the speed of the drive. This will cause a more gentle pumping action and increase the life of your tubing. Since many slurries are also viscous, slowing down the drive speed will also increase the efficiency of the pump.