Compared with a piston pump, a peristaltic pump has the following characteristics
The peristaltic pump can provide a wide range of filling volume, 0.1ml ~ 500ml. Of course, it depends on different hose diameters. When changing the filling volume, you only need to replace the hose with the appropriate diameter, and you don't need to purchase and reserve the pump body compatible with other filling volumes.
From the perspective of sterility:
The plunger pump is composed of many mechanical parts, which are in contact with products, such as seals, plunger, pump body, and valve (if necessary). These parts undoubtedly need to be assembled, cleaned, and sterilized before use. As the disposable packaging technology has been developed, if the peristaltic pump is used with disposable discarded packaging materials (buffer bag, hose, filling needle), it can avoid any cross-contamination caused by the filling circuit and reduce the workload of cleaning verification.
Even if the plunger pump is equipped with SIP / CIP function, the economic impact of its time and energy consumption also needs to be considered.
From the perspective of product applicability:
1. There is a gap between the piston and the pump body of the piston pump. When the piston of the piston pump compresses the high-speed liquid medicine through/into the small aperture channel, the shear force may have a potential impact on some biological products sensitive to shear force.
2. If the viscosity of the product is high, the piston pump is easy to produce larger pressure in the inner cavity when the piston extrudes the liquid medicine, and this pressure is easy to affect the filling accuracy in the micro filling, while the filling pressure of the peristaltic pump is relatively low.
3. Some products react to metal parts, so the filling kit made of primary packaging materials without metal parts also avoids the contact between liquid medicine and metal.
Taking a certain brand filling pump as an example, this paper briefly describes the mechanism of the peristaltic pump
The pump head of the peristaltic pump has two roller groups, each group has several rollers;
Two hose tubes pass through a group of rollers to form a channel;
Then the two channels meet in a Y shape, and the squeezing pulses of the two channels are superimposed to cancel each other. After that, the "no" pulse liquid is filled into the vial through the precisely controlled motor. In the market, for the filling volume of more than 1ml, some brands of peristaltic pumps can achieve the filling accuracy of + / - 0.5%. Moreover, with the online weighing feedback system of the scanning machine, the stability of the filling can be ensured, and there is no obvious difference between the filling accuracy and the plunger pump. Of course, the hose has a great influence on the overall performance of the peristaltic pump. The wall thickness uniformity, fatigue resistance, or material memory of the hose are important reference factors that need to be paid attention to in the selection.