How to Choose a Peristaltic Pump for Laboratory Liquid Transfer

When choosing a peristaltic pump for laboratory liquid transfer, the first question is often simple:

What is the maximum flow rate?

However, maximum flow rate is only one part of the selection process.

Different laboratory applications may require very different conditions. Some experiments need only a few milliliters per minute, while others require several hundred milliliters per minute. Some systems run for a few minutes, while others operate continuously for several hours.

The type of tubing, system pressure, liquid properties, and whether the pump needs to run in both directions can also make a significant difference.

So, how should you choose a peristaltic pump for laboratory use?

1. Start with the Actual Flow Rate

The first step is to determine the flow rate that your experiment actually needs.

For example, if your application normally requires 70–200 ml/min, a pump that can adjust within this range may be more useful than simply choosing a pump with the highest possible flow rate.

For the ZP300, the reference flow range depends on the tube size:

• ID 3.2 × OD 6.4 mm: approximately 70–235 ml/min
• ID 4.8 × OD 8 mm: approximately 120–450 ml/min

The actual flow rate of a peristaltic pump is not always a fixed value.

Tube size, tube material, pump speed, liquid properties, and system pressure can all affect the final flow rate.

For laboratory equipment, it is therefore better to focus on the normal working flow range rather than only looking at the maximum flow.

2. Why Does Tube Size Affect Flow Rate?

This is one of the most important things to understand about peristaltic pumps.

A peristaltic pump moves liquid by repeatedly compressing flexible tubing. The tube inner diameter therefore has a direct effect on how much liquid is moved with each cycle.

In general, a larger tube ID allows a higher flow rate.

However, a larger tube is not necessarily better for every application.

A smaller tube may be more suitable when lower flow is required, while a larger tube can be useful for higher flow applications.

When choosing tubing, consider:

• Required flow rate
• Liquid compatibility
• Working pressure
• Temperature
• Operating time
• Tube durability

3. Tubing Material Matters

For a peristaltic pump, the liquid mainly comes into contact with the tubing.

This makes tubing selection particularly important.

The cheapest tube is not always the right choice. The material should be compatible with the liquid and operating conditions.

Silicone Tubing

Silicone tubing is flexible and relatively economical. It can be suitable for general liquid transfer where strong chemical resistance is not required.

For long-term operation or special liquids, however, compatibility between the silicone tube and the liquid should be checked before use.

Norprene Tubing

Norprene tubing offers good chemical stability and temperature resistance and can be considered for applications where tube durability is important.

Its reference operating temperature range is approximately -59°C to 135°C.

Under suitable conditions, tube life can reach approximately 1,000 hours. Actual service life depends on factors such as pump speed, liquid, pressure, and temperature.

For this reason, a stated tube life should be treated as reference data rather than a fixed service life for every application.

4. When Is Forward and Reverse Operation Useful?

Some laboratory systems only need to move liquid from point A to point B.

In other applications, the liquid may need to:

• Return to the original container
• Drain from the tubing
• Change transfer direction
• Empty the tubing
• Move between different containers

In these situations, a reversible peristaltic pump can make the system easier to operate.

For example, the ZP300 can change the pump rotation direction using a direction switch, allowing the liquid transfer direction to be reversed.

This can be useful when developing laboratory equipment or small automated fluid systems.

5. Consider Tube Life for Continuous Operation

One important characteristic of a peristaltic pump is that the tubing is a consumable component.

The pump head repeatedly compresses the tube during operation. Over time, this mechanical stress can cause the tube to wear.

Under otherwise similar conditions:

Lower pump speed → less mechanical stress on the tube → potentially longer tube life.

However, actual tube life also depends on:

• Pump speed
• Liquid
• Temperature
• Pressure
• Tube material
• Operating time

If a laboratory system needs continuous operation, tube replacement should therefore be considered during the equipment design stage.

6. Don't Ignore System Pressure

Flow rate is not the only parameter that matters.

If the liquid system has significant back pressure, the actual flow may differ from the flow measured under low-pressure conditions.

For example, the ZP300 has a reference positive pressure of approximately 0.18 MPa and negative pressure of approximately -0.095 MPa.

For a real application, however, the complete tubing system should be considered, including tubing size, tubing length, pressure, and liquid properties.

7. A Simple Peristaltic Pump Selection Process

If you are selecting a pump for laboratory equipment, the following process can help.

Step 1: Determine the flow rate

Do you need 10 ml/min, 100 ml/min, or 400 ml/min?

Step 2: Identify the liquid

Is it a water-based liquid, food liquid, or a liquid with special chemical properties?

Step 3: Select the tubing

Choose the tube ID and material based on the required flow and liquid compatibility.

Step 4: Check system pressure

Determine whether the application has significant back pressure.

Step 5: Consider operating time

Will the pump operate for a few minutes or continuously for several hours?

Step 6: Decide whether speed control or reverse operation is needed

If the flow rate or liquid direction needs to change during the experiment, these functions can be useful.

8. A Practical Example: ZP300

For applications requiring approximately 70–450 ml/min liquid transfer, an adjustable peristaltic pump such as the ZP300 can be considered.

Different tube sizes can be used for different flow ranges, while the pump speed can be adjusted with a control knob. Forward and reverse operation is also available.

However, this does not mean that the ZP300 is suitable for every laboratory application.

The final selection should still be based on the actual flow rate, liquid properties, pressure, temperature, and operating time.

Conclusion

Choosing a laboratory peristaltic pump is not simply about finding the pump with the highest flow rate.

Several factors work together:

Flow rate + tube size + tube material + pressure + operating time + liquid properties.

Considering these factors before purchasing can make it easier to achieve stable liquid transfer and manage tube life during operation.

For laboratory systems requiring approximately 70–450 ml/min and adjustable flow with reversible operation, the ZP300 can be one option to consider.