One of the fastest-growing types of positive displacement pumps on the market is the peristaltic pump. Once used exclusively in the lab, this pump has been transformed for use in process control, water treatment and plant production. Yet it remains largely unknown to many people, despite its many advantages.
The popularity of the peristaltic pump – a.k.a. tubing pump – can be attributed to its design. An electric motor turns a set of rollers, which compress and release flexible tubing as they rotate. This squeezing action creates a vacuum that draws fluid through the tubing. Because the flexible tubing is the only wetted part, maintenance and clean up is simple and convenient.
The peristaltic pump creates a contamination-free pumping system. The fluid being pumped remains inside the tubing at all times and thus never comes in contact with any pump gears, seals, diaphragms, or other moving parts. As a result, finding a pump compatible with a particular solution is as simple as choosing the correct tubing which may need to be chemically compatible to the product.
This makes peristaltic pumps ideal for transferring chemically aggressive or abrasive solutions as well as high-purity fluids. There is no need to worry about corrosion or wear and tear on parts, and no need to worry about contamination. Moreover, most types of pump tubing can be sterilised through autoclaving, gamma irradiation or ethylene oxide gas application, and most systems facilitate steam-in-place (SIP) and clean-in-place (CIP) techniques. This ensures complete sterility of the entire pump system with minimal cost.
Peristaltic pumps are simple to operate and easy to customise. They are self-priming, and many models have interchangeable pump heads that can be mounted in minutes using finger-tightened screws. Engineering advances have yielded designs that allow the tubing even in large process pumps to be loaded or replaced in seconds. In addition, most pumps feature simple controls, with a dial or keypad for speed control, and straightforward menus for programming more complex tasks.
Peristaltic pumps require very little maintenance beyond tubing replacement. Tubing must be replaced periodically to offset reduced flow performance. This procedure typically takes just seconds, which can be an advantage when using the same pump to transfer or dispense different chemicals. When solutions are changed, only the tubing needs to be changed, and the pump can be up and running within minutes.
In addition, many tubing pumps are designed with high Ingress Protection (IP) ratings, which means they can be hosed down for quick, thorough cleaning.
Peristaltic pump systems are compatible with a wide range of tubing materials, including silicone, thermoplastics, Viton, and even rigid PTFE. There are also newly developed formulations of bi-layer, or co-extruded tubing, in which a long-life tubing material is laid over a thinner inner material that is compatible with aggressive chemicals, resulting in a tubing that’s collective properties in a pump exceed those of either material alone.
Many tubing types also meet United States Pharmacopoeia (USP), Food and Drug Administration (FDA), U.S. Department of Agriculture (USDA) and/or National Sanitation Foundation (NSF) agency requirements. This makes peristaltic pumps suitable for handling a variety of fluids, from sensitive cell cultures to industrial solvents, and allows the same pump to be used in multiple applications simply by changing the tubing.
Multimedia pumping capabilities
In addition to generating enough suction to self-prime, peristaltic pumps create sufficient vacuum to successfully pump most viscous fluids — including those too heavy for other types of pumps. Yet, because these pumps employ a gentle pumping action that leaves solid components of the fluid, including cell walls and particulates, intact, they are excellent for moving sensitive fluids, slurries and suspended solids.
Peristaltic pumps are also used to move liquids, gases and mixed-phase fluids. If gas bubbles are present in the fluid stream (for instance, through out-gassing from solution), they can be pumped right along with the liquid portion without any flow disruption. For this reason, peristaltic pumps can also run dry without damage.
Peristaltic pumps are relatively inexpensive to operate. They are cost effective because they are easy to clean, they are effectively impervious to the most abusive, pump-damaging chemicals, and, because the same pump can be used for multiple applications this results in lower labour costs, lower maintenance costs, less downtime, and increased production.
Peristaltic pumps have become a critical and reliable part of processes ranging from chemical transfer to pharmaceutical processing to wastewater treatment. Their versatility and ease of use has helped them meet a multitude of fluid-handling challenges.
INSTRULAB – A DIVISION OF AIR & VACUUM TECHNOLOGIES
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