Approaches to reduce flow pulsation on peristaltic pumps and principles

Peristaltic pumps inherit with flow pulsation as a natural result of the way in which the pump operates by compressing the tubing.   There are several approaches that can be used to reduce flow pulsation in peristaltic pumps.  The principles behind these approaches to reducing flow pulsation in peristaltic pumps involve minimizing the amount of disruption to the flow of the fluid and allowing the fluid to pass through the pump smoothly and evenly.  A few commonly used methods are discussed herein: 

• Increase the number of rollers: By increasing the number of rollers in the pump, the flow pulsation can be reduced because the fluid is being displaced more frequently.   Take the DG15 series pump head as an example.  DG15-24 with two channels has 4 rollers and can generate flow rate as high as 1800 mL/min while the DG15-48 and DG15-28 have 8 rollers which can generate smooth and less pulsatile flow.  However, the flow rate is less than the DG15-24 pump head. The max flow rate of DG15-28 and -48 is about 75mL/min.  Thus, it's a tradeoff when selecting high flow pump and pumps with smooth flow. 

Fig 1. DG15 series pump heads with 4 or 8 rollers 

• Use a high-compliance tubing: Using a tubing with high compliance (i.e. flexibility) can help to reduce flow pulsation because it can absorb some of the pressure fluctuations that are generated by the rollers.   A long and flexible tubing introduced helps to reduce flow pulsation because it can absorb some of the pressure fluctuations that are generated by the rollers. 

• Implement active control systems. These systems use sensors and control valves to actively adjust the flow in rea-time to eliminate flow pulsation.  For example, install flow meters inline with peristaltic pumps. These devices can measure the flow rate and provide feedback to control systems, allowing for more precise control of flow.  A variety of flow meters with different working mechanisms, including variable area flow meters, differential pressure, turbine, paddle-wheel sensors and ultrasonic can be found here:  https://www.auroraprosci.com/fluid-handling/Flow-Meters 

• Use flow-modifying components:  These components, such as orifices, nozzles, and flow straighteners can be used to change the flow characteristics and smooth out the flow.  

• Use a pulsation dampener: A pulsation dampener is a device that is placed inline with the pump and hose, and it acts to absorb the shock of the fluid being displaced and smooth out the pulsations in the flow.  One example of flow dampener is illustrated below. 

Fig 2. Example of internal structure of a typical flow damper

• Special pump head with a phase compensation mechanism that drives two channels alternatively.  A special tubing (see image below) is split into two channels on inlet of the pump head and the rollers squeeze the fluid through the tubing in the pump head, where after it flows into one channel again.  The two channels operate 180 degree out of phase to eliminate flow pulsation.  This pump head is suitable for flow rates application. For example DMD-15 pump head can generate flow ranging from 80 mL/min to 2070 mL/min with different tubing IDs.  

Fig 3.  Schematic of DMD-15 phase compensation mechanism to eliminate flow pulsation 

If you have any questions or need assistance to reduce the flow pulsation in your peristaltic pumping systems, please feel free to reach out to us at sales at auroraprosci dot com!