Peristaltic pump _ constant flow pump accuracy is 0.5% to 1%. Usually users will be two common problems:
1. Now that peristaltic pump accuracy can reach this level, but sometimes when we use a pump distribution of more than 2ml when the accuracy can be achieved, but in the sub-2ml when the following can not be satisfied?
2. Pump head speed is low, why the naked eye to see the pump tube liquid flow pause phenomenon?
Answer as follows:
1. Peristaltic pump is by squeezing the runner to achieve constant current output, that is, each revolution will produce a fixed flow output. However, peristaltic pump wheel in the process of rotation, each time leaving the pump tube, the liquid will be due to the pump tube rebound and back to absorb the formation of a sudden decrease in discharge flow rate that pulse. There are usually several squeeze wheel peristaltic pump, it will see a few pulses in the discharge port. If our pump has 2 pressure rollers, it generates 3 ml of flow per revolution, if you want to dispense 1 ml. This means that the pump needs to run only about 1/3 revolutions and the peristaltic pump can not guarantee the reproducibility of the flow within one revolution due to the presence of the runner pulse. As long as the peristaltic pump flow is greater than the amount of fluid produced per turn, the peristaltic pump will stop at that point when it was last started when it stopped dispensing.
CONCLUSIONS: The peristaltic pump flow rate is selected to exceed the per-turn rate of the peristaltic pump.
2. When the pump head speed is low, see the pump inlet pause phenomenon, which is due to the wheel just pressure pump tube, the smaller the inner space of the pump tube, so the liquid in the back row state, so At this time the flow of liquid forward flow offset by the row back. However, this does not affect the normal discharge of the liquid, so the discharge accuracy is still constant.