Peristaltic pumps are indispensable in many industries, from pharmaceuticals to environmental protection. Because a single drive can pump multiple fluids simultaneously and without cross-contamination, peristaltic pumps offer a flexible and cost-effective solution for multi-channel fluid transfer.
Other advantages of peristaltic pumps include the ability to pump liquids over long distances, self-priming, and the handling of liquids containing suspended solids. Peristaltic pumps offer continuous flow, consistent performance, and reliable operation. Thanks to their multi-channel pump head, they can also pump multiple liquids simultaneously without cross-contamination.
Introduction to multi-channel peristaltic pumps
Technicians in research labs and production facilities often need to pump multiple fluids and channels simultaneously. Multi-channel peristaltic pumps offer a cost-effective solution to this problem, saving time, space, and resources.
Multi-channel peristaltic pumps use a single motor to drive multiple pump heads simultaneously. This saves space and allows for multi-channel pumps in a compact design. The adjustable motor speed allows specialists to control the flow rate and operating time of each channel simultaneously, thus varying the flow rate proportionally across all channels.
Multi-channel peristaltic pumps use a single drive motor, which requires less space and has fewer moving parts than other pump types, resulting in lower operating costs and lower energy consumption. This makes peristaltic pumps simple and economical to operate, but they require regular maintenance to ensure optimal performance. One of the most common maintenance procedures is the periodic replacement of the pump tubing, as it wears out over time. Peristaltic pumps offer a wide range of replacement pumpheads, motors, and tubing for a wide range of applications, including fluid transfer, metering, and dispensing. They are successfully used in a variety of industries, including pharmaceuticals, chemicals, biotechnology, food processing, printing, agriculture, and water treatment.
One of the key advantages of peristaltic pumps is their flexibility. The pumped fluid remains within the hose, so only this part of the pump comes into contact with the fluid. This significantly reduces the risk of contamination, ensures better control of the fluid composition and purity, and ensures process reliability.
Other advantages of peristaltic pumps include ease of installation, protection against internal backflow, and the following specifications and selection criteria to consider when evaluating peristaltic pumps:
- Liquid flow rate
- Properties of liquids
- Chemical compatibility of pipes
- Easily replaceable tubes
- Flexible pump design, e.g. interchangeable pump heads
- Overall accuracy between channels
- Torque requirements
- Block control function
Components of the peristaltic pump
Peristaltic pumps consist of three main components: the motor, the pump head, and the pump tubing. Since the pump tubing is the only component that comes into contact with the fluid being pumped, it must be compatible with it. Click here to learn more about pump tubing and chemical compatibility.
Four engine types
Peristaltic pumps typically use one of four motor types:
- AC motors consume the same amount of electricity as lighting and other appliances.
- A brushed DC motor uses brushes to transfer direct current to the rotor within a magnetic field. When loaded, the rotor rotates in one direction.
- A brushless DC (BLDC) motor uses an electronic controller to power the inner rotor . Brushless motors do not require brush replacement , reducing maintenance costs.
- Stepper motors deliver electrical current to a series of magnets surrounding the rotor, rather than to the rotor itself. Because the electrical current can be delivered as a series of digital pulses, stepper motors offer greater precision and control.
Technical properties of pumps and pipes
The flow rate and fluid dynamics of a peristaltic pump can be influenced by the tube size, the pump manifold design, the geometry of the tube block arrangement, the number of cylinders and the overall diameter of the cylinder block.
Each hose and pump head combination has unique performance characteristics .
For example, hoses with a higher wall thickness to inner diameter (ID) ratio can generate greater suction force than thin-walled hoses of the same ID and are therefore recommended for more viscous fluids.
pump hose
For all pump heads, the inner diameter of the tubing is directly proportional to the flow rate. As the tubing and rotor diameter increase, the buffer space (the space reserved for the fluid in the tubing between adjacent coils in the pump head) increases, thus determining the flow rate per head revolution.
High-precision pump tubing with tight tolerances must be used, and the pump itself must be calibrated to ensure accuracy. “High tolerance” means that the inner diameter and wall thickness of the pump tubing are maintained within extremely precise tolerances during the manufacturing process. Small changes in the pump tubing dimensions directly result in small changes in the flow rate.
Pump calibration by adjusting motor speed, run time, or clogging level (the pressure force acting on the pipe) can reduce variability and improve repeatability. Pumps should always be calibrated according to actual operating conditions, including fluid type and operating temperature.
Most pump tubing materials require an adjustment period during which the shape memory and fluid flow rate adjust and stabilize. The length of this period depends on the tubing size and material. For maximum accuracy, the new pump should be run for at least 10–15 minutes with new tubing before calibrating the flow rate of each channel.
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Multi-channel pump lines can be used independently or split into multiple lines using a manifold (e.g., a Y-piece). Using a manifold as a common inlet or outlet for multiple pipes reduces the number of pipes from the source to the receiving tank. Pump outlet lines can also be combined to increase flow.
Multi-channel manifolds can reduce flow pulsation when using offset pump heads. Be sure to use larger diameter tubing on the single-channel side of the manifold (above or below the pump) to reduce cavitation and pump backpressure .
Masterflex offers dual Y-assemblies with platinum-vulcanized silicone hoses.
Liquid type
Single-channel and multi-channel pumps handle fluids with similar properties. Low-viscosity fluids, such as water, flow easily through pipes of various sizes. High-viscosity fluids, on the other hand, may require larger-diameter pipes and relatively low pumping speeds.
Low-viscosity fluids flow smoothly and with minimal wear through pipes of any diameter. High-viscosity fluids require larger-diameter pipes and lower pumping speeds (rpm).
Types of peristaltic pump heads
There are three types of peristaltic pump heads:
- Stackable single-channel heads
- Multi-channel head
- Cartridge head
Multi-channel heads and cartridges allow the placement of several hose channels in a relatively small space.
Frequent tubing changes can significantly increase the time required for pump setup and maintenance. Some multi-piece pump heads must be disassembled or removed from the motor to replace the tubing. Other types of multi-piece pump heads , such as most cartridge pump heads and multi-channel pumps, are easier to install and maintain because the tubing can be removed and replaced without disassembling the pump head.
Stackable single-channel pump heads
Single-channel pump heads can be stacked and added or removed as needed. This is one reason why they are popular in applications requiring flexible pump design. They are also ideal for applications with large pipe diameters, high suction lifts, or high discharge pressures.
Depending on the speed range and axial thrust, two to four pumpheads can be installed on one motor. The MasterFlex L/S Easy-Load II dual-channel pumphead allows four pumpheads to be installed on one motor, providing up to eight channels. Multiple pumpheads can be of the same type or compatible with different tube sizes. This allows for a combination of tube sizes or pumphead types to achieve the desired flow rate. Flow ratios over 100:1 are possible.
Stackable pump heads with offset cylinders reduce torque loading in the pump circuit when two or more pump heads are stacked on top of each other. Depending on the position of the end cylinder, stackable pump heads with offset cylinders can deliver slightly different fluid volumes between channels during short dispensing sessions or when dispensing small doses. These differences are likely to disappear during continuous pump operation or when dispensing volumes exceeding hundreds of milliliters.
Cartridge pump head
Pump heads are designed for a specific maximum number of channels. Depending on the pump head and motor power, you can use any number of channels. Pump heads are available individually or as part of a pump. Masterflex L/S pump heads are modular and compatible with most Masterflex L/S motors. A single pump head supports up to 12 channels, each with a flow rate of 0.0005 ml/min.
The cartridge pump’s long cylinder design allows for simultaneous fluid transfer between cartridges thanks to a larger number of cylinders compared to single-channel pump heads. This reduces pulsation and ensures greater precision at low volumes and flow rates. This makes the cartridge pump head ideal for pumping small volumes and low flow rates.
Pumpheads with adjustable clogging compensation cartridges offer the highest channel-to-channel accuracy of any pumphead. They can adjust the clogging in each channel to compensate for small changes in tubing dimensions that can cause slight flow rate variations.
Multi-channel pump head
Multi-channel pump heads combine many of the best features of cartridge heads and multi-channel heads.
Multi-channel pump heads can be stacked with up to 32 channels, depending on the pipe diameter, fluid composition, and axial thrust. These heads offer relatively low flow pulsation across two, four, or eight channels without the need for cartridge pump heads. Flow is synchronized between channels, eliminating the need for clogging correction. This combination of features gives multi-channel pump heads the stacking flexibility of single-channel pump heads (with synchronized flow) and the throughput of cartridge pump heads.
The Masterflex L/S multi-channel pump head is suitable for use with micro-perforated tubing and Masterflex L/S tubing.
Selecting a pump head control unit
Selecting the most suitable variable speed motor for your application depends on the required torque, power, and speed. Low-speed motors offer higher torque and allow for greater clearance between the pump head and pipe than high-speed motors.
Variable frequency drives (VFDs) are typically used as the main drives. These drives enable simultaneous flow control in all channels and ensure that the flow in the secondary channels is proportional to the flow in the main channels.
Different speeds and gear ratios result in different torques, and different pipe sizes result in different power outputs. This means you can achieve different performance levels by adjusting the motor speed or choosing different pipe sizes.
Digital controllers enable precise and repeatable speed control, ensuring accurate flow rates. They also display flow rate, pump motor speed (rpm), and dispensed and accumulated volume over multiple cycles. Unless multiple flow meters are installed in the system, flow rate and volume are typically displayed for a single channel.
Liquid application
Constant-flow, constant-speed pumps are popular for their consistent performance, line load stability, and ease of use. Combined with precision extruded tubing, these pumps offer channel-to-channel transfer accuracy of 3 to 5%. This accuracy is suitable for a wide range of applications, including large-volume fluid transfer, heat exchangers, and ink transfer in printing plants. The Masterflex I/P constant-speed pump system is designed for flushing systems and is available in three- and four-channel versions.
Cartridge and multi-channel pump heads are typically used in applications requiring precise sampling, dosing, and measurement of liquids. Synchronized cylinders ensure coordinated fluid transfer between the pump head channels.
Applications requiring high performance and precision include precise dosing and measurement, analytical research and quality control, and environmental sampling and monitoring. Multi-channel pump heads offer flow accuracy of 1.5% to 2%. Pump heads with adjustable cartridges offer flow accuracy of 1%.
Choose a solution with a multi-channel peristaltic pump
Peristaltic pumps combine excellent fluid transfer performance with the configuration flexibility required for multi-channel applications. A wide selection of tubing sizes and materials, interchangeable pump heads, and motors allow you to efficiently adapt your pumping system to your desired performance.
Multi-channel peristaltic pump systems are suitable for a wide range of applications and save time, space, and resources. Contact us today to discuss the pump, head, and hose options best suited to your needs.