Filling and dosing machines are packaging machines which measure out a product from a bulk supply by some predetermined value, e.g. volume, level in a container, mass or count. The filling method used is influenced largely by the nature of the product e.g. liquid, gas, piece goods, powder, free flowing solids or sticky paste, but also by the measure for selling the product e.g. by weight, by volume or by count.
However, it does not necessarily follow that products which are sold by volume have to be measured by volume, for example oils which are sold by volume are frequently filled by weight because the density of the oil varies significantly with temperature; conversely products like rice or frozen peas which are sold by weight may actually be filled by volume because this can be done at higher speed and lower cost. In fact it is not uncommon for products sold by count to be filled by weight.
Filling machines may comprise of one or a number of dosing devices that may be arranged with or without a mechanism to control containers or packages as they are filled.
Fill & Seal machines undertake the filling function as described above, but incorporate a sealing mechanism to close the container in a variety of ways (see Sub Pages). These machines are distinguished from Form Fill and Seal machines (see Form Fill Seal Pages) in that they fill and seal pre-made packages or containers. A separate Page covers dedicated Closing machines.
Volumetric and level filling is typically associated with liquid or gas products, but a whole range of products also use this technology including dry products such as powders and granules, pet foods, through to semi-liquids such as gels and pastes, or even products which are normally solid at room temperature like fats, lipstick and stick deodorants.
Different methods of filling have been developed not only to accommodate the different characteristics of the product but also to achieve various accuracies of fill, because while for a low value product there may be no incentive to fill more accurately than the statutory requirements, for high value product increased accuracy can represent a considerable saving in product "giveaway".
The filling of powders and free flowing solids poses particular problems because of the generation of dust and variations in bulk density. Very dusty products are typically filled using auger fillers or vacuum fillers, but where the bulk density of product varies significantly it will usually be necessary to combine this with a weight correction mechanism like a checkweigher because typically these products are sold by weight.
The filling of carbonated drinks like soft drinks or beer and products like liquid detergents which have a tendency to foam also poses significant problems which are typically solved using a technique called "bottom up filling", where the filling nozzle is inserted into the container and slowly raised during the filling process so that the mouth of the filling nozzle is always kept below the level of the liquid.
At their simplest filling machines can be single head bench mounted devices that are manually operated and at their most sophisticated rotary fillers which can incorporate scores of filling heads and be able to fill and seal thousands of cans every minute.
The two most common arrangements of fillers with multiple fil