In contrast, the only component of a peristaltic pump that comes into contact with the product is the tubing. If the tubing is a single-use item that is supplied pre-sterilized, the need for cleaning and sterilization is eliminated, as is the risk of cross-contamination.
Extending validation periods in aseptic and sterile processes by providing single-use tubing sets and predictable pump-service intervals is an important aspect of product development at Flexicon. Part of Watson-Marlow Pumps Group, Flexicon offers single-use tubing sets, each of which is supplied complete with a validation package.
The DAFPA (disposable aseptic fluid path) sets are supplied double-bagged and gamma-irradiated ready for use. Various single-use tubing-set configurations are available. These include the required pharmaceutical-grade silicone tubing for the pump and, depending on the application, a sterile filter, aseptic quick-connect fittings, prefillable product bag, and filling nozzle.
Production managers switching from piston pumps to peristaltic pumps are often surprised at the highly accurate, pulsation-free flow that modern peristaltic pumps achieve. In addition, sophisticated electronic control of the pump motor enables the flow rate to be ramped up, maximized, and ramped down again, thereby reducing aeration and foaming so that short cycle times can be maintained. It is not unusual for peristaltic pumps to be used on filling systems processing up to 150 bottles per minute.
Flexicon’s pumps are normally fitted with a pumphead having two sets of six rollers, with the two sets of rollers offset from each other. Product is drawn through two parallel tubes and, after exiting the pumphead, the flows are combined via a Y-connector so that the pulsation from the two sets of rollers is combined. The resultant smooth flow is comparable with that achieved using piston pumps down to microfill levels.
With appropriately sized tubing, peristaltic pumps can deliver volumes down to 0.5 mL at an industry-standard accuracy of +/-0.5%; smaller volumes can be delivered with an accuracy of +/-1%. Typical high-speed filling machines use in-process checkweighing to monitor the filling accuracy and, if necessary, the output from this can be used in a closed-loop pump-control system.