Vacuum filler

A vacuum filler is a special kind of bottle filler that works by making use of air pressure. When you open up the top of the bottle, air rushes in and fills up the empty space, creating pressure. Normally, this would push the liquid out of the bottle and make a mess, but in a vacuum filler, the liquid is kept closed off with a valve until enough pressure builds up. When you release the valve, the pressure drops suddenly and the liquid is sucked in to fill up the empty space. This way, you can fill up the bottle without making a mess or spilling any liquid. Imagine blowing up a balloon and then quickly letting the air out - that's how a vacuum filler works!