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Technology

The Technology Behind Vacuum

 
How Does Vacuum Work?
The principle behind Vacuum Compression is not based on mechanical, but atmospheric pressure. The negative pressure or vacuum in the press results in a difference of pressure with the surrounding atmosphere. This difference of Δp = 0.95 bar exerts a force of 95 kN evenly distributed over the panel's surface.

Natural Atmospheric pressure: patm

Pressure in Press (Vacuum): ppress

Pressure Difference (Force): Δp = patm - ppress

How Big is the Force?

The maximum pressure is:

  • Δp = 0.95 [bar]
  • Δp = 950 [mbar] or [hPa]

This results in a compression force of:

  • F = 95 [kN] ≈ 9.5 [t/m2]

Imagined as a one-dimensional mechanical force, this three-dimensional compression force could be seen as a 3.8 m high concrete block positioned on the panel.

Is the Force Sufficient?

Yes, it is. This is best proven by over 20 running production lines, some of which have been installed over 10 years ago.

In comparison with hydraulic presses, whose force goes up to 50 t/m2, the force seems to be quite small. The differences, however, are considerable. The hydraulic pressing method relies on a one-dimensional mechanical force which is not distributed evenly, while vacuum creates a three-dimensional and uniform pressure.

This has important effects on the produced panel:

Quality of Glue Joints:
Hydraulic Press
  • Mechanical force (One dimension)
  • Glue joints without pressure
  • Bad glueing
Vacuum Press
  • Atmospheric pressure (Three dimensions)
  • All Joints with the same pressure
Planarity of Panels:
Hydraulic Press
  • Panel is bent
  • Gaps have to be filled
  • Expensive foundations and floor load
Vacuum Press
  • Pressure on panel only
  • Guaranteed planarity
  • No deformation of the press

Technical Approval

The panels produced with the woodtec vacuum press have official approval for load-bearing components. This certification is put at the disposal of our clients.

 

Experiments

Various experimental test confirm the vacuum pressing method and the quality of the produced panels: