Back to basics

21 Apr 2016

People laugh sometimes when I say I work with vacuum. "Your work is to create nothing" is a common reply. I wondered if there was a better reply and started digging into the matter. So, let's start at the basics.

Wikipedia states that "vacuum is a space void of matter". You can also find definitions that vacuum happens when the pressure is so low that any particles in a space do not affect any processes being carried on there. In applied physics and engineering, on the other hand, it is probably more helpful to view vacuum as a negative pressure, as this is the force that can be harnessed to do work.

The first example of man-made vacuum is usually attributed to Evangelista Torricelli, who in 1643 filled a glass tube with mercury and turned it upside down in a dish of mercury. Some of the mercury remained standing in the tube, held up by the weight of the surrounding atmospheric pressure. Torricelli had created the barometer, and alongside millimeters or inches of mercury (mm Hg or inHg), Torricelli (Torr) is still used as a unit to measure both vacuum or pressure.

It took until the 20th century for vacuum to become a valuable industrial tool with the introduction of incandescent light bulbs and since then, the use of vacuum has exploded.

But what about us at Piab? We use compressed air to generate vacuum. Aren't they opposites? To use a high pressure to create a "space void of matter"? That leads me to Bernoulli's principle that states that an increase in the speed of a fluid occurs simultaneously with a decrease of pressure. That is the exact thing that happens when you take a shower and the shower curtain moves from hanging in a neutral vertical position to moving towards the high flow of the water stream in the shower. Or, where there is a strong stream of water flowing, it automatically draws water from the side streams and generates a flow from the side streams to the main high flow stream.

Using those analogies, it makes it easier to explain both what vacuum is and how you actually can relate to vacuum in everyday business... AND how Piab uses high pressure air pushing through a very small cartridge with openings on the sides while automatically pulling atmospheric air from the surrounding area to generate vacuum. Fascinating, isn't it?