Peristaltic pump for viscous liquid transport
Number of hits:5662017-01-06 08:15:01 Sources: http://www.084290.com/jsfw/n42.html
The working principle of the peristaltic pump is essentially depend on the elasticity tube to form a vacuum, using atmospheric pressure liquid extraction. The liquid is completely surrounded by a hose. Due to the natural tightness of peristaltic pump, so that the size of the head of the peristaltic pump flow almost no effect.
In fact if each hose squashed can recover at the next time before being squeezed again, peristaltic pump flow will remain unchanged. So it is very important to maintain the original shape of the hose to maintain the flow. This explains the two problems, the first peristaltic pump peristaltic pump: why the highest speed is no more than 650RPM, the hose springback is the need for a very short time, if the speed is too high will cause the hose is not rebound to the original again by the roller extrusion, will destroy the peristaltic pump flow linearity; second: the effect of suction on the size of the peristaltic pump flow is large, when the absorption process is relatively large, atmospheric pressure on the liquid support will be offset by a lot of hose will be relatively large rebound resistance, will extend the hose rebound time, causing the hose is not to rebound before the original shape will be again when the two roller extrusion, between the liquid volume package decreases, and make the peristaltic pump flow decreases.
Fluid flow through the pipeline, the pipeline will be subject to the resistance of the wall, there are three reasons for the size of the resistance:
The first is whether the inner wall of the pipe is smooth, the inner wall of the pipeline is more smooth, and the resistance to the fluid is smaller;
Second: the size of the pipe diameter, pipe diameter is smaller, the greater the resistance to fluid;
Third: the length of the pipeline, the pipeline length is longer, the fluid resistance is greater, even in the water and the absorption process is zero, if the suction end of the pipe is more than ten meters or tens of meters in length, the flow is a big influence.
The liquid viscous transmission, pipeline resistance will be doubled, so to control the various unfavorable factors, according to the above analysis, we can know that the first to choose the smooth wall pipe, one end of the suction pipe second to choose the larger diameter, length of the third end of the suction hose must be short, and a very important point is to choose the thick wall pipe, thick walled tube with elastic thin-walled tube is much higher for liquid viscosity has very obvious advantage.
The fluid viscosity is very high, the peristaltic pump transmission when do not have to run at the highest speed, because the fluid viscosity is very high, the peristaltic pump flow curve is a parabola like downward opening shape, so through adjusting the appropriate speed, to achieve the highest transmission flow, rather than at the highest speed.