Peristaltic Pump Manufacturers

1 2 3 Next >

Results 1 to 25 of 74

About Peristaltic Pumps

Peristaltic pumps are positive displacement pumps, which offer isolation from the environment and any moving part. A biological process called peristalsis inspired the conception of these pumps. Organs like the esophagus and organisms such as earthworms exhibit this process. These pumps are best suited for transfer of sterile, environment sensitive, and highly viscous fluids. The mentioned factors logically make it perfect for medicinal and sanitation applications.

Working Principle:

The working principle involves suction of fluid towards relatively low-pressure region from a high-pressure one. The pumping can be achieved by both circular and linear encapsulation of the liquid inside the flexible tube. Constriction of the tube in these pumps is referred to as occlusion and subsequent release is called restitution. Pumping is attained by constricting the tube and increasing the low-pressure volume until enough vacuum is created to pull the liquid towards it.

Pump Construction:

Pumps of this nature are classified into two, based on the principle of vacuum generation for the suction of fluid.

1. Rotary
2. Linear

Rotary type peristaltic pumps are uncomplicated; they comprise of a flexible tube running across a casing in a circular fashion. The motor shaft's center is made to align with the center of the tubing and casing. A setup, consisting of at least two rolling shoes with no less than 180° difference between them, is constructed. The difference of 180° prevents a probable malfunction after few cycles.

Linear type peristaltic pumps, on the other hand, are a bit more elaborate, since occlusion and restitution need to occur like an oscillating wave. This is achieved by a setting of multiple linearly arranged shoes, which constrict the tube based on a statically eccentric motor and shaft system. The shoe setup has a boring to let the shaft run perpendicularly through it. To enable an oscillatory function, the boring on each of these rods is placed at different vertical levels.

Circular pumps:

Liquid is encapsulated between the two shoes after low pressure is generated by the previous combination of shoes. The volume per cycle in a circular type pump is independent of the distance between the shoes, when the number of shoes is even. On the other hand, the volume per two cycles is independent of the distance between two shoes when the number of shoes is odd. The number of shoes also adds to the perception of continuous flow.

Linear pumps:

Unlike circular pumps, the linear pumps' characteristics are dependent on the span of vacuum and liquid capture cycle. Output per cycle is indifferent to the even numbers of the capture cycle and output per cycle becomes independent of odd number of capture cycles after two cycles of pumping.

In both circular and linear types, the construction should adhere to good design practice, which requires equidistant shoes. This avoids the output to be dependent on the probability of a particular shoe initiating the operation of the pump. These pumps are capable of handling 25 psi of pressure and with latest breakthrough in material technology, pumps handling pressures up to 40 psi can also be custom designed.

Material Selection:

Since the only part in contact with the fluid is the pipe, it is imperative that the material should be chemically compatible with the fluid flowing through it. Hence, the material should be resistant to chemical shocks at both room temperature and elevated temperatures because at elevated temperatures chemical resistance tends to decrease. This forms the basis for one of the factors affecting the selection of material for the tube. Apart from the chemical compatibility of the material, the fatigue resistance of the tube is also of prime importance. From the above mentioned constraint, it is quite apparent that the process warrants that the material should retain its original size and shape, even after repeated occlusions. Furthermore, the amount of occlusion is directly responsible for the efficacy of the pump itself. Thus, material selection in relation to the tube is a very narrow fit and it needs to be an elastomer. Since most of them are chemically incompatible, lined tubes offer relatively better performance. Lined tubes have their inner surfaces laminated with chemically compatible material and outer surfaces are constituted by material that satisfies the physical requirements of the material. A draw back in the above mentioned case is that the deterioration of the laminated surface has to be constantly monitored, failure of which leads to leakage and eventual contamination of the fluid. The lamination chemical can be monitored by adding color substitutes. An accurate selection process entails a tedious tabulation of chemical and physical compatibility of material. This process has become simple in the recent times with easy access to chemical compatibility software. After material identification, it is usually followed by an immersion test to corroborate the software forecast. Immersion test necessitates weighing and measuring the tube made of the chosen material. The tube is then immersed in the fluid, which it is supposed to transport. After the stipulated 48-hour wait, the tube is weighed and measured after rinsing and cleaning the tube. Any anomaly in the physical characteristic beyond a tolerance of ±5-10% is indicative of its incompatibility. The test parameters, if fulfilled by material, are further subjected to pump test. Substitution of the test material in a working peristaltic pump under normal working conditions constitutes the pump test. Further endurance tests for pressure and temperature can be done at the user’s discretion. Auxiliary factors such as transparency, cost, gas permeability, and regulatory approval can also have an impact on a case to case basis.

Occlusion:

Occlusion of the tube is of primary importance because of its impact on the efficacy of the pump as well as fatigue resistance of the tube. A tradeoff between the two factors has to be made since more squeezing leads to better vacuum creation and thereby higher efficiency, whereas lower constriction leads to a better tube life. Good design practices require fixing the occlusion at an earlier stage to avoid wear and tear of the tube and malfunctioning of the pump. However, occlusion can also be fixed at a later stage in case of non-availability of a replacement material of better quality or otherwise. To avoid aberration of the tube exteriors, lubricants are filled in the casings. These lubricants contribute to better fatigue resistance of the tube, thereby allowing increased occlusion.

Occlusion rollers or shoes are classified into two types - fixed and spring. As the name suggests, the fixed type runs over the tube with a fixed support, whereas the spring type has the tube supported by a spring system, which allows for a constant occlusion even with varying pressure and tube width.

Pump Efficiency:

Pump efficiency is reliant on factors such as the amount of vacuum generated and rpm of the motor. The vacuum generation itself is dependent on the distance between the shoes and occlusion. Increased occlusion and distance between the shoes results in efficiency in terms of power consumed and volume per cycle. The rpm of the motor is also a contributing factor. Although the number of cycles per minute increases the efficiency, the designer has to be cognizant of load characteristics of the motor, fatigue of the tube, and process requirements. At user's discretion, the above mentioned parameters are fixed to cater to their need for higher output or better tube life.

Channel Classification:

Apart from their working principle, peristaltic pumps can further be classified by the number of channels and their ability to branch off and amalgamate channels. These pumps are generically called multi-channel peristaltic pumps. The classifications are as follows:

• Flow dividing
• Discrete channel
• Common channel peristaltic pumps

Flow dividing pumps consist of a flow splitting mechanism to supply multiple destinations at the same time, from a single source. Discrete channel peristaltic pumps are the ones transporting fluid from multiple sources to multiple destinations discretely. The shoe setup is separate for each channel and need not be synchronized with each other. The shoe setups are driven by a single motor in most of the cases. Additionally, a mechanism to disengage a system is also put in place to avoid unnecessary fatigue of the tube serving the idle channel. Common channel peristaltic pumps are used to increase the flow rate by adopting a timing mechanism in the shoe setup, which entails an overlapping of the vacuum generation cycle and liquid transportation cycle between different channels. This allows for improved flow rate and better use of motor power. Dosing for a process with different sterile fluids can be done using Flow dividing pumps.

Tube Classification:

As tubes form a major part of the pump setup, pumps are further classified based on the characteristics of the tube. The choice of tube is reliant on the pressure generated in the pump. Any pump handling more than 12 psi is usually fitted with reinforced tubes called hose. Such pumps are called hose pumps.

Applications:

• Dialysis
• Aquarium water supply
• Blood transfusion
• Blood supply
• Sewage handling
• Pharmaceutical production
• Production of Edibles
• Removal of blockages

Advantages:

• Ease of maintainability
• Environmental isolation
• Ability to handle high viscous fluids
• No back flow
• Hygienic

Copyright ©2024 Zycon Global Services, LLC
By using Zycon, you agree to our Terms of Use. No portion of this site or its content may be copied, modified, reproduced, transmitted, distributed, or reverse engineered without the express written permission of Zycon.