Peristaltic Pump- As from the name it’s clear that these pumps work on the principle based on the natural physiologic function of peristalsis. This word was first coined in 1859 and its origin is from a Greek word - Peristaltikos. Definition of Peristalsis- Successive waves of involuntary contraction passing along the walls of a hollow muscular structure (esophagus, intestine , tubing in case of pumps) and forcing the contents outward

 

Natural Peristalsis

The working Principle-

Operating Principle is Simple, It has two main parts:-

1. The Tube or Hose

2. The Shoes and Revolving motor

I'll Discuss about different types of tubes and revolving motor system later, for now let's see about the Operating Principle of Peristaltic Pumps

 

Objective:-

We want liquid to be pumped from one source to another without coming in contact with motor parts.

 

How is it done-?

1. There are two ends of the pump tubing - one from which the material goes in and other from which the material comes out. The inlet tube is attached to a source to which the material has to be pumped and the outlet tube is attached to the place where the material has to be delivered.

2. Now this tube is installed on the revolving rotor system which has shoes or rollers to push the material in forward direction.

 

Simple peristaltic pump

Step1-

Tube /hose are fixed between the tube bed and the rotor/ shoes. At each location the tube is squeezed (Position A, B, C)

 

Step2-

When motor is switched on their roller move across the tube/ hose in rhythmically squeezing the tube along its length in direction of revolving rotor.

 As the roller moves forward the part of the tube which was squeezed recovers and come back in it's normal form.(Tubes are elastomeric) This process result in formation of vacuum.Step3-

 

Step4-

There is more than one roller which successively presses the tube. The part o liquid/material between the two rollers makes a 'Pillow'. This pillow is the actual pump chamber and determines the volume per 'roller step' and hence flow rate.

Pillow formaton


Step5- 
 

The Pillow Volume will depend upon following features

Inner diameter of the tubing,

Tubing properties,

The drive and pump head specifications

The liquid or material been pumped.

The physical application condition.

 

That is all about the working of peristaltic pump.