Net weighing fillers, while accurate, are slow. Filling by hand means an operator must scoop up a product before weighing to ascertain how near they are to the target volume.
The length of time per dose can be considerable, and creates a high probability of variance from dose to dose.
It takes a long time to obtain an “acceptable” volume of target material using the simpler dose methodologies of manual hand filling/weighing.
Where traditional auger fillers are useful in large doses filling applications of dry powdered or granular products, Marta Romaniuk & Richard Lewis of the Biopharma Group believe they lack the level of precision required for the delivery of small incremental doses with close-tolerance, repeat accuracy.
The measuring tool selection must consider dosage and the size and shape of primary containers. This might affect the operator’s ability to dose their desired volume per minute or hour.
As a result, assistance from powder filling instruments has expanded across many markets, from pharmaceutical and diagnostic reagents, cosmetics, powdered metals and food.
In the volumetric powder filling approach, material is drawn-up in to an orifice of known dimensions using an integrated vacuum system.
The optimal filling system and procedure is then determined by the application for which they are used, and on the properties of the process material, such as:
- Bulk density
- Free flowing or non-free flowing
- Coarseness, concentration gradients and uniformity of powder
- Container type
During the selection of base machine, volumetric dosing barrel and filter type, variation in size of powder particles – from several microns to more granular volumes – must be taken in to account.
This may also improve the dosing capacity. In some cases, larger filter pores (40µm as opposed to 20µm) may improve the airflow through the dosing gun and aid in the products compaction. This would reduce potential product waste by simultaneous dose and filter purge.
During the dosing process, the residue powder inside the dosing chamber and on top of the filter will be expelled accurately by applying a pressure, defined by the user.
Kinematics specialises in this volumetric technique. It is partnered with the Biopharma Group.
They conduct a sample test protocol to identify the key powder and container characteristics. The outcome should provide a clear understanding of:
- The level of vacuum required to pick up and adequately pack material, without compromising its structure
- The depth of the product in the given dosing gun to calculate the volumetric measurements
- The level of tolerance expected when applying these aspects to the dose
Various Kinematics systems are available to simplify operation and increase productivity. All are supplied complete with extensive build diagrams, wiring configurations, and FDA approved parts, where required.
