Accuracy and repeatability in precision dispensing and dosing

Louise Davis

The method of using a positive displacement technology for the dispensing or dosing of liquids can bring many benefits to those for whom repeatability, precision, reliability and accuracy are important.

preeflow volumetric dispensing pumps have found applications in sectors such as electronics and semiconductor manufacturing, aerospace, medical device assembly and pharmaceuticals – from the application of small quantities (microlitres) of adhesive to the dosing of fluids into vials. The assurance that the dispensed volume will always be the same to within a high level of tolerance is very valuable to critical processes.

An example of where preeflow’s volumetric dispensing capability meets an industry need is in the application of adhesive in medical catheter manufacturing. Adhesives are used in the bonding of balloons and hubs to lumens, marker bands, and manifolds and connectors. This is an industry where accuracy and repeatability are of paramount importance in achieving a consistent, validated process. Since the nature of the assembly means that full automation is not always feasible, the bonding process can be manual. Catheters have small bond areas, and squeeze out or witness of excess adhesive would be unacceptable, so adhesive placement and amount need to be precise. The use of a preeflow eco-PEN, triggered by a foot pedal, gives the assembly operator more control of this intricate operation and confidence in the adhesive amount.

preeflow volumetric pumps dispense from the microlitre range on up, to an accuracy of ±1% independently of viscosity, while exhibiting low shear force on any media. They can dose continuously at rates up to 60ml per minute. The direction of flow can be reversed leading to clean cut off of the material, preventing drips or stringing.