How Does a Peristaltic Pump Work?

What is peristaltic pump?

Peristaltic pumps are positive displacement pumps that are used to pump various types of fluids. The fluid is contained within an elastic tube – which is built or installed inside a circular (or linear) pump encasement. Peristaltic pumps can be used to deliver a precisely measured volume specific load of liquid material. Variable speed peristaltic pumps are used for continuous pumping at a variety of motor speeds. The concept of a peristaltic pump was born out of a mechanism called peristalsis. Peristalsis is a series of muscle contractions that support the automatic processes of the digestive system. With peristaltic pumps, the flexible tube is compressed between the pump housing and the rollers. The rollers are housed within the pump head. The compressed portion of the tube forces the liquid material through the tube, which delivers the desired dose of fluid. In the medical field, peristaltic pumps enable safe delivery of pharmaceuticals and other critical liquids to the patient. Because the fluid being delivered only contacts the inside of the tubing, they provide flexibility for transferring fluid, maintaining sterility and reducing contamination. The flow rate of the pump can be controlled or adjusted by simply adjusting the size of the pump or the rate of rotation of the pump head. The pumps can support a range of flow rates based on their size. Pumping of shear-sensitive fluid can also be accomplished with use of peristaltic pumps. Peristaltic pumps also deliver exceptional flow control and flexibility. Pharmaceuticals and other critical solutions can be administered in specific doses of mL/min, or blood can be pumped through external filters for dialysis.

The Pros and Cons of Peristaltic Pumps

While beneficial to the medical industry, peristaltic pumps have numerous pros and cons. Here is a brief overview of them.

Pros	Cons
Eliminates contamination hazards	Tubing / hoses can leak over time, resulting in reduced efficiency
Can handle toxic, viscous, or shear-sensitive media	Low pressure
Simple installation and low-cost maintenance	Require routine cleaning and maintenance
Built-in back-flow prevention without additional equipment, such as valves	Intermittent flow rate and pulse rate

 

Components Frequently Used by Peristaltic Pump Manufacturers

The four common types of motors for peristaltic pumps are:

• Brushed direct current (DC motor)
• Brushless direct current (BLDC motor)
• Alternating current (AC motor)
• Stepper motor

The flexible tube in the pump can be made from materials like silicone, natural rubber, fluoropolymer, or polyvinyl chloride (PVC). Peristaltic pump manufacturers find natural rubber generally offers the most resistance, compared to other materials. For chemically corrosive media, fluoro elastomeric materials are often used to protect the tubing from corrosion. Corrosion can lead to decreased efficiency and leaks, which can be quite dangerous. It is important to give special consideration to the diameter of the tubing utilized. In order for these peristaltic pumps to work properly, the wall thickness of the tubing must line up with the space between the roller and the housing of the pump head. Such consideration can aid in maximizing the life of the tube. Pump manufacturers must also adapt to the evolving needs of the customer. Cutting-edge technology and innovative methodologies are key in developing the gold standard for peristaltic pumps.

Peristaltic Pump Suppliers

Peristaltic pump suppliers are selective in determining which pump manufacturers to supply to consumers. Since peristaltic pumps are used for a wide variety of functions, quality requirements for the different pumps vary. For this reason, many peristaltic pump suppliers supply pumps that are employed in many different industries. These industries include:

• Food and beverage
• Biopharmaceutical
• Water and waste treatment
• Chemical
• Print and packaging
• Ceramics

OEM peristaltic pumps are purchased from pump manufacturers for use in other equipment. OEM peristaltic pumps are generally not standalone units, but are intended for incorporation with another device or system.

How are Peristaltic Pump Flow Rates Determined?

A peristaltic pump head can often accommodate different pump tube sizes. Tubes with a different inner diameter will result in different flow rates. When the inner diameter is larger, the flow rate will be higher. In contrast, when the inner diameter is smaller, the flow rate is lower. Ideally, the peristaltic pump will generate a consistent flow rate each turn. These ideal conditions do not take the viscosity of the liquid into consideration. Liquids with a higher viscosity will generally have a lower flow rate and use a tubing with a greater wall thickness.
 
   

Considerations for Peristaltic Pumps

One of the most common factors to consider when purchasing a peristaltic pump is the ease of use. Ease of use can include the operation of the pump and the convenience of easy maintenance. For example, the amount of time it takes to change the tubing on the pump. Another consideration could be the number of rollers that are used. The number of rollers has a direct impact on how the pump handles fluids. Moreover, more rollers can help maintain consistent levels of pulsation. The size of the pump is important to consider as well. The size affects the amount of fluid the pump is able to deliver. In addition to their medical uses, small peristaltic pumps can be used in laboratories. Some peristaltic pumps are more efficient than others and can offer multiple channels. Multi-channel pumps allow different media to be pumped simultaneously through different tubes. If you are considering a multi-channel peristaltic pump, cross-contamination must be avoided. Peristaltic pumps also may have special features that allow you to adjust pressure levels. This is a useful feature that can help adjust the pump when using different types of tubing. For example, when transitioning from the use of a soft silicone tubing to a tough fluoroelastomer tubing material.

Your Trusted Partner for Peristaltic Pumps

RBC Medical is a pioneer in the medical device industry. With over 25 years of experience, our engineering team has the experience you need for FDA-approved device manufacturing in the U.S. Contact us today to find out why over 93% of customers have chosen RBC Medical as their preferred partner for medical device projects.