The peristaltic pump is one of the more simple pumps in the categorie Positive Displacement Pumps. The peristaltic pump has no valves, diaphragms or plunjers. It consists of a hose and a rotor with two or more rollers. The hose is connected in the pumphouse, preventing it to move. The liquid only has contact with the inner side of the hose.

When the rotor rotates, the hose is being squeezed together by a roller. Because the hose is squeezed together, a sealed pumpchamber is being created, which pushed the liquid further down the hose. Behind the roller, the hose regains it's form which leads to underpressure, sucking the liquid into the hose.

The hose has to meet up to high requirements, since this is the most important part of the peristaltic pump and the only part that has contact with the liquid. The hose has to be flexible enough to regain it's normal shape when squeezed together, but at the same time it has to endure the pressures from the liquid and rollers. The time the hose needs to regain it's shape is important for the flow, cause this effects the speed of the pump. A pump with a hose that regains it's form slowly will not be able to process much liquid. Another important requirement of a hose, is it's chemical resistance. When processing acids, the hose should be able to handle those liquids. There are different hoses available for different liquids. For nutrition, the hose has to meet up to a certain quality requierement. When pumping abrasive liquids, the hose should be able to sustain these liquids. There are many hose-materials which have an optimal use for every circumstances.
But it's not only the material of the hose that has influence on these principles. The liquid itself can affect the elasticity from the hose. When a liquid has a high viscosity rating, the elasticity-limit of a hose is achieved sooner, creating a slower fillrate.

The advantages of the peristaltic pump
- The peristaltic pump has zero leakage.
- The liquid will stay clean within the pump
- The pump can be run dry.
- Because the hose is the only part that has physical contact with the liquid, this is the only part that needs to be replaced, when the pump has to be cleaned.
This pump is suitable for abrasive, highly viscous and dense products. The pump is most often used with the preparation of Pharmaceutica, nutrition and other similar sorts of materials.

Lab

Laboratorium peristaltic pumps are low pressure hose pumps. They have a capacity characteristic which is linear until the maximum pressure of 1.5 bar. With increasing pressure, the capacity decreases. This makes the laboratorium peristaltic pump alse suitable for dosing pumps.
Low pressure hose pumps are often constructed with 2, 3 or more rollers that provide the necessarry pressure on the hose. The number of rollers affect the capacity of the hose pump, since the volume of the hose decreases with every roller. The advantage of more rollers, is that the liquid flow is more smooth, since the pulsations created by the rollers are closer to each other. The pressure from the rollers are adjustable, creating the option to have backflow inside the hose. Some liquids require this, since it won't damage the liquid this way.

Industrial