Page 741 - Fluid Power

Piab Vacuum Academy PVATM
Vacuum theory What is vacuum?
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. At sea level it is usually 1,013 mbar = 101.3 kPa. 1 Pa equals 1 N/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 100,000 N. By reducing the pressure in a closed space the atmospheric pressure becomes a potential energy source.
A vacuum cleaner does not suck. Air and dust are pressed into the vacuum cleaner by the surrounding higher atmospheric pressure.
A suction cup adheres to a surface by the surrounding higher pressure.
Altitude above sea level
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 2,000
A definition for vacuum is:
m, the pressure is reduced by around 1% per 100 m. An application which is dimensioned to hold 100 kg at sea level, can manage only 89 kg at an altitude of 1,000 m.
The chapter “Tables” shows the effect of the atmospheric pressure on the vacuum level.
1. Atmospheric pressure = 0 at an altitude of 1,000 km
2. 1 bar (101.3 kPa) at sea level
At the summit of Mount Everest (8,848 m) the atmospheric pressure is approximately 330 mbar (33 kPa).
”A room without matter”. In everyday language; ”Air-free or almost air-free space”.
Source: Nationalencyklopedin, Bra Böcker, Höganäs, Sweden.