The flow rate of a peristaltic pump is measured in ml/min. It’s generally described as a range, such as 0-10 ml/min (or a-b). The actual flow rate is a number and is proportional to the pump’s rotational speed. The formula is:
Rotational speed * Flow rate per revolution = Flow rate.
1. Rotational speed: The rotational speed of a peristaltic pump varies depending on the type of motor. AC and DC motors have a fixed speed, while stepper motors are variable speed motors. Generally, OEM peristaltic pumps are recommended to operate below 300 rpm (to consider hose lifespan), while peristaltic pumps with a housing are recommended to operate at a maximum of 600 rpm.
2. Flow rate per revolution: This is a core design parameter of the peristaltic pump. Different flow rates per revolution are the main parameter that distinguishes different peristaltic pumps. The unit is ml/rpm. For example, the K25S peristaltic pump has a flow rate of 4 ml/rpm, while the K4024 peristaltic pump has a flow rate of 6 ml/rpm.
3. Flow Rate: A flow rate of 0-10ml for a peristaltic pump typically indicates its minimum flow rate is 0ml/min, meaning the pump is stopped and not running. 10ml represents the maximum flow rate (OEM speed 300rpm, peristaltic pump with a housing speed 600rpm).
Generally, the peristaltic pump’s speed and flow rate are directly proportional (linear relationship); the higher the speed, the greater the flow rate. However, there is a maximum value (According to the resilience of the pump tubing or fatigue, please see how to choose the flow rate of a peristaltic pump). Therefore, changing the flow rate primarily involves changing the speed. If the desired flow rate cannot be achieved by adjusting the speed, the only solution is to increase the pump’s operating time.