Pneumatic Tube System - How it works
The driving force of a pneumatic tube system is pneumatics. Pneumatics can be traced back to Hero of Alexandria in the 1st century AD.
Imagine a hot summer day, relaxing on a terrace with a cold drink and a straw... By sucking on the end of the straw you create a vacuum in it. The liquid in the glass will be sucked into the straw by this vacuum. The liquid level in the straw is going down again, when you gently blow into the straw. This is the working principle of pneumatics.