Tag: Volumetric Filler

Whitepaper: Dry Filling

Written on by John Henry

In previous papers I discussed liquid filling. This month I’ll talk about dry, or solids, filling. There are many types of dry products ranging from fine powders like talc or flour, to irregular pieces like frozen chicken parts. Other types of dry products include pharmaceutical powders, regular shaped products like nuts and bolts, candies and pharmaceutical tablets.

A variety of filling technologies are available. Many times more than one technology will give satisfactory results on a particular product/package combination. In most instances, there is one technology which will give the best results when all factors are considered.

Dry filling technologies can be broken down into 3 basic categories:

  • Volumetric filling dispenses a measured volume of product.
  • Weight filling dispenses a measured weight of product.
  • Piece filling dispenses a specific count of product.

Sometimes the package label claim will determine the technology to be used. Two popular candy mints are packed in similar containers. In the 90’s and prior, one of them claimed a certain weight of mints on the label. The other claimed a specific number of mints. To assure label claims were met, one had to be filled by count, the other by weight.

Download the complete Dry Filling Whitepaper to continue learning about dry or solid filling.

Whitepaper: Piston Fillers

Written on by John Henry

Last month I discussed cosmetic or level style fillers. These fill a container to a certain level and fill volume is determined by the volume of the container. This is fine for many products, but others need more precise volume control. Volumetric fillers provide precise fills independently of the container. They do this by measuring physical volume, as in a piston filler. Other architectures measure the product by weight, mass or flow.

Level filler precision is typically rated by the distance from the top of the container. Volumetric fillers precision is typically rated by percentage accuracy. A volumetric filler rated at 1% accuracy would be expected to fill a 10oz container to +/-0.1oz. Some high precision models can fill to +/- 0.1% accuracy. This precision can be critical when filling a high value product like a pharmaceutical that might cost thousands of dollars an ounce. This rating is typically expressed as six sigma. This means that 99.7% of all fills will be within specification absent any extraneous factors.

Piston Filler Design

The most common volumetric filling technology is based on cylinder/piston combinations of various types. Regardless of details, all piston fillers include a piston, cylinder, and inlet and outlet valves. Most pistons used for filling are single acting and that will be the focus of this paper. Single acting means that they fill and discharge one dose per stroke.

There are a few companies that make double acting piston fillers that discharge one end of the cylinder while simultaneously filling the other. This allows them to fill 2 doses per fill cycle. This increases speed but adds complexity that is not usually necessary.

The dosage volume of a piston filler is a function of the diameter and stroke (linear travel) of the piston. A 5cm cylinder has an area of 19.6cm2 If the piston travels 10cm the total volume displaced will be 196cc (cubic centimeters). Fill volume is controlled by adjusting the length of the piston stroke.

Download the complete Piston Fillers Whitepaper to continue learning about the typical piston filler design.

 

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