The main factors that affect the accuracy of peristaltic pump

Peristaltic pump is a kind of tubing pump, relying on the flexibility of the tube to work, can be used to continuous transmission and filling, the liquid only flows through the tube, so the health level is the highest of all kinds of pump. Peristaltic pump has a good self-sealing, can be simplified in the pipeline design, so in recent years, more and more filling machinery began to use peristaltic pump as a filling unit. However, some of the structural characteristics of the peristaltic pump will cause accuracy error during transmission, the following to explain in detail the reasons and solutions.

Peristaltic pump transmission of liquid is a share of a transmission, if the amount between each share is equal, then whether it is filling or continuous transmission can get very accurate results. The volume of the liquid is the volume of the tube between the two rollers of the peristaltic pump. The formation of this cavity has two factors: first, need two rollers to be cut off, and secondly, the tube itself needs to have Elasticity, the flexibility of the tube during operation will change, so the volume of the cavity will change, resulting in the problem of transmission accuracy.

A new tube with a cross-section is circular. When it is squeezed on the peristaltic pump for a few minutes, the cross-sectional area of the tube will become elliptical (see figure below), the time is very short and the oval shape will gradually become more elliptical shape, the process is relatively long, the amount of change is relatively slow, so the new tube flow rate attenuation at the beginning is relatively fast, and will gradually slow down until the hose ruptures.

 So the peristaltic pump precision problems are all around the elasticity of the tube, resulting in changes of the elasticity of the tube including three reasons, first, the elastic characteristics of the tube itself, Second, the pump head size accuracy ; Third, the amount of change of the transmission of liquid.

First explain the reasons for the first, the flexibility of the tube itself is determined by two aspects, one is the material problem, the other is the size of the tube, the tube material is no longer explain for details here, please see "Types and Selection of Peristaltic Pump tubings". The problem with the size of the tube is well understood. In the case of the same wall thickness, the greater the inner diameter of the tube, the worse the elasticity, on the contrary will be better; in the case of the same diameter of the tube, the thicker the wall thickness , The better the flexibility, and vice versa is worse. So when the high precision is required, it is improtant to use the appropriate size of the tube to minimize the resulting error.

Second, explain the reasons for the second aspect of the pump head accuracy, in the case of the same tube, if the gap between the wheel and the arc is too small, or the gap is not uniform, will cause the tube was over-squeezed, Resulting in the tube plastic deformation and dramatic changes in the flexibility of the tube, which ultimately affect the transmission accuracy. Uneven pressure pipe, will lead to a significant reduction in tubing life, therefore increasing the cost of peristaltic pump.

Thirdly, regarding the amount of change in the transfer liquid. The amount of change in the same type of liquid can be summed up by two factors. First, the amount of change in the temperature of the transfer liquid, because the tube is a flexible plastic body, different temperatures, will make its elastic changes, Said the higher the temperature, the worse the flexibility of the tube; second, the transmission of liquid night changes (that is, peristaltic pump suction range changes), because the peristaltic pump absorbs the liquid depending the elasticity of the tube, so the effect of suction the peristaltic pump has a large effect on the flow rate of the peristaltic pump (the head lift of the peristaltic pump has little effect on the flow rate) because the resistance generated by the suction line will directly counteract the resilience of the tube and affect the size of the rebound cavity.

If we want to improve the accuracy of peristaltic pump, it is necessary to exclude optimization according to the above factors one by one. First, the choice of a higher elastic material of the tube, and try to use the size of a reasonable tube; second, using of higher quality peristaltic pump head, ZHUNZE pump head has done a comprehensive optimization for the above effects factors, basically can be ruled out because the impact of the size of the pump head; third, to ensure uniformity of transmission of liquid, and liquid surface stability.

The above is the problems of the peristaltic pump using in the case of high-precision transmission need to pay attention to, in the conventional transmission, that is, the accuracy is not very high occasions, some problems can be negligible.

This article is write by Baoding ZHUNZE Precision Pump Manufacturing Co., Ltd. original, without authorization can not be reproduced!