Vacuum Theory 101

What is vacuum?


A vacuum cleaner does not suck – air is pushed in by the surrounding higher atmospheric pressure.

A definition for vacuum is: “A room without matter“.
In everyday language; “Air-free or almost air-free space“.
Nationalencyklopedin, Bra Böcker, Höganäs, Sweden.

When using the terms ”vacuum”, ”negative pressure”, ”suction”, etc., we mean a pressure that is lower than the atmospheric pressure, which is the pressure of the weight of the air above us.

By reducing the pressure in a closed space the atmospheric pressure becomes a potential energy source.


(1) Atmospheric pressure = 0 at an altitude of 1,000km (2) 1 bar (101.3kPa) at sea level

(1) Atmospheric pressure = 0 at an altitude of 1,000km
(2) 1 bar (101.3kPa) at sea level

Altitude above sea level

At sea level atmospheric pressure is usually 1,013 mbar = 101.3 kPa.
1 Pa = 1N/m2

Which means that a column of air with a cross-sectional area of 1 m2 presses on the surface of the earth with a force of around 100,000N.

A suction cup adheres to a surface by the surrounding higher pressure.

As the atmospheric pressure is the working force, the force will consequently change with the atmospheric pressure. This means that the present barometric pressure and the altitude above sea level must be taken into consideration.

Up to 2,000m, the pressure is reduced by around 1% per 100m. An application which is dimensioned to hold 100kg at sea level, can manage only 89kg at an altitude of 1,000m.