The peristaltic pump is a kind of hose pump, which depends on the elasticity of the hose to work, can be continuously transmitted, can also be filled, the liquid only flows through the hose, so the sanitary grade is the highest of all pump types. Peristaltic Pump has good self-sealing, in the design of the pipeline can be simplified, so in recent years, more and more filling machinery began to use peristaltic pump as filling unit.
But the peristaltic pump because of some of its own structural characteristics, will make the peristaltic pump in the use of transmission accuracy problems, the following to explain in detail the reasons for the emergence and solutions. Peristaltic Pump transmission Liquid is a load of transmission, if the amount between each share is equal, then whether filling or continuous transmission can get very accurate results. The volume of this liquid is the volume of the hose cavity between the two rollers of the peristaltic pump, and there are two factors in the formation of this cavity: first, the need for two rollers to squeeze the cutoff, and second, the need for the hose itself to be elastic, the hose in the process of operation elasticity will change, so the volume of this cavity will also change,
The problem of transmission accuracy is created. A new tube, the cross section is round, and when squeezed on the peristaltic pump for a few minutes, the cross-sectional area of the hose becomes oval (see figure below), the change time is very short, and this oval shape will gradually become a more elliptical form, the process is relatively long, the amount of change is also relatively slow,
So the flow rate attenuation of the new pipe at the beginning is relatively fast, the future will gradually slow down until the hose rupture.
Therefore, the precision of the peristaltic pump is all around the change of hose elasticity, resulting in the change of hose elasticity is divided into three reasons, first, the elastic characteristics of the hose itself; second, the size accuracy of the pump head problem; Third, the amount of change in the transmission liquid. First of all, explain the first reason, the elasticity of the hose itself is determined by two aspects, on the one hand is the problem of materials, on the other hand, the size of the hose problem, the problem of hose materials is no longer detailed here, details see “peristaltic Pump Hose type and selection.” The problem of hose size is well understood, in the case of the same wall thickness, the larger the inner diameter of the hose, the worse the elasticity, the better the opposite, the thicker the wall of the hose under the same inner diameter, the better the elasticity, the worse the reverse.
Therefore, in the high precision requirements of the occasion, to choose the right size of the hose to minimize the resulting error. Secondly, explain the second aspect of the cause, the size of the pump head problem, the same hose, if the gap between the roller and the arc is too small, or the gap is not uniform, will cause the hose local excessive extrusion, so that the hose produces plastic deformation, resulting in drastic changes in the elasticity of the hose, which ultimately affects the accuracy of transmission.
Uneven pressure tubes can also lead to a significant reduction in the life of the hose, thus increasing the cost of using the peristaltic pump. The third aspect, about the amount of change in the transmission liquid. The amount of change of the same liquid can be summed up by two factors, first, the amount of change in the temperature of the transmission liquid, because the hose is an elastic plastic body, different temperature, will make its elasticity change, generally speaking, the higher the temperature, the worse the elasticity of the hose; second, the change of the transmission liquid at the night
Because the peristaltic pump absorbs the liquid by the elasticity of the hose itself, the change of the suction process has a great influence on the flow rate of the peristaltic pump (the head of the peristaltic pump has little effect on the flow rate), because the resistance generated by the suction process directly offsets the ability of the hose rebound and affects the size of the rebound cavity. To improve the accuracy of the peristaltic pump, it is necessary to eliminate the optimization according to the above factors one by one. First, the use of higher elasticity of the hose, and try to choose a reasonable size of the hose, and second, the selection of high-quality peristaltic pump head, to eliminate the impact of pump head size, optional peristaltic pump head for the above factors to do a comprehensive optimization, basically can be excluded because of the size of the pump head caused by the impact;
And the stability of the liquid surface. The above is the peristaltic pump in the application of high-precision transmission needs to pay attention to the problem, in the conventional transmission, that is, the requirements of accuracy is not very high occasions, some problems can be ignored.