Filling machines can be broken down in to 3 main categories: manual, semi-automatic and fully automatic. There are also two main filling technologies used – vacuum level filling and volumetric filling.
Manual Liquid Filling Machines
Manual liquid filling machines use a piston within a cylinder to force liquid into the container.
Known as volumetric filling, this technology dispenses the same volume every time.
The volume of liquid dispensed is pre-set by the operator for repeatability and can be changed within the available output volume range of the machine (between 100-500ml, for example). These machines require no power supply, are compact, and can often be bench mounted.
The operator positions the container in to the filling machine, pulls the lever until the end-stop is reached which forces the liquid out of the nozzle, into the container. In almost every case, manually operated liquid filling machines fill one container at a time.
Manual filling machines can be configured to work with a variety of liquids and a wide range of viscosities.
Depending on the liquid’s viscosity and volume dispensed per cycle, filling speeds of 15 containers per minute are likely.
Semi-automatic liquid filling machines
Semi-automatic liquid filling machines fulfil the same purpose as manual machines but have a source of power which allows for higher productivity.
Semi-automatic filling machines can have up to four filling heads, meaning 4 containers can be filled simultaneously which greatly increases productivity.
Many semi-automatic filling machines use the same principle as manual filling machines to dispense liquid into the container, but rather than pulling a lever, the operator either presses a foot pedal switch, or simply positions the containers in place and they fill by themselves; depending on the filling technology used.
Semi-automatic filling machines can be either freestanding, mobile units or bench-mounted and can draw liquid from either a hopper or from a separate vessel via feed tubes.
Fully automatic liquid filling machines
Fully automatic filling machines can be either volumetric filling or vacuum level filling and have the added production benefit of a bottle handling system to manoeuvre containers through the filling stage and seamlessly on to any further processes such as cap placement and label application.
Additional processes can also include nitrogen purging to remove oxygen from the top of filled bottles and individual serial number printing.
Commonly, containers will be placed on to a rotating feed table or similar mechanism which feeds containers into the filling machine as required. Caps can also be fed into the system via a rotating hopper which can correctly orientate them and position them in a chute for placement.
Depending upon a variety of factors, fully automatic filling machines will either fill each container in turn, or in batches of up to 12 containers at a time before releasing them to make way for the next 12 containers.
Fully automatic filling machines can be highly productive, filling up to 150 bottles per minute with anything from 5ml to 5.5 litres.