Autotutorial for Peristaltic Pumps
How do they work?
Peristaltic pumps are positive displacement pumps utilizing flexible tubes full of liquid and a rotor. Positive displacement means that a set a amount of flow rate will be delivered to the system regardless of the pressure on either side. As the rotor turns, it squeezes the flexible tubing forcing a specific amount of fluid out of the pump.
Pump Speed
The rotor on the peristaltic pump sets the pump speed by how many revolutions per minute that the rotor will turn. We have two types of pumps we currently utilize, one can vary between 1-100 rpm. You may encounter a pump with a capability up to 600 rpm. Check the pump as different ones in Process Controller software require different VIs to operate.
Flexible Tubing Sizes
For each tubing size, different pump speeds will correspond to different flow rates being output by the pump.
The peristaltic tubing sizes are rather arbitrary and are labeled by numbers: 13, 14, 16, 17, and 18 in increasing order of size.
The table below gives you an idea of the flow rates that can be achieved by a peristaltic pump for different tubing sizes.
Tubing Number |
13 |
14 |
16 |
17 |
18 |
|---|---|---|---|---|---|
Tubing Size(ID) |
0.8 mm |
1.6 mm |
3 mm |
6.3 mm |
8 mm |
Pump Speed (rpm) |
~2-100 |
~2-100 |
~2-100 |
~2-100 |
~2-100 |
Flow Rate (mL/min) |
0.1-6.0 |
0.3-21.0 |
1.3-80.0 |
4-280 |
6-380 |
From this chart, you can easily calculate a pump speed given a tubing number and flowrate. At the appropriate tubing number, divide the given flowrate by the maximum flowrate and multiple this quantity by 100. This simple calculation will give you the speed of the pump in rpms given a tubing size and flow rate.
What tubing size and pump speed would you use to acquire a flowrate of 500 mL/min? Keep in mind that you can use more than one pump head...