Get an 8 page pdf that explains some liquid filling machine principles for free by clicking on the image below.
copied from the internet
This is a link to an equipment supplier, but makes no comment/judgement on the company or its equipment. It is only posted as it seems to contain interesting technical information.
This nice and simple explanation of how gravity filling works is one of the many useful pieces of information on the APACKS website.
from: APACKS (click image for full story online)
This shows clearly how the fill volume is controlled by the very simple tactic of stopping the escape of air from above the filling liquid. The gravity in the name of the filler refers to the force that causes the liquid to flow, namely gravity rather than piston, auger or positive displacement.
Have a look at the site and see the different types of filling equipment available.
Aseptically packaged milk and juice has probably had the biggest impact of any technology in the beverages industry in the last 50 years.
One of the packaging machines of the Tetrapak, the company that started the trend by fabricating an aseptic machine, is pictured below.
from: TetraPak (click image for full story online)
This page actually contains an interactive diagram of the filler where you are able to look at key aspects of the machine and its design.
A nice way to view these multi million dollar machines!