The principles of insulation drying:
In positive pressure drying, the insulation is flooded with dry, heated air through special openings.
During the course of the flooding phase, the dry air becomes enriched with moisture from the insulation material, escapes via the edge joints or other relief openings into the room and is dried again by means of installed dehumidifying units.
Via this cycle, drying to the material-specific balanced humidity is achieved.
In the vacuum method, the entire procedure is reversed. The moist air is extracted from the insulation by means of vacuum turbines.
In this way, a vacuum is created in the insulation which causes air from the room, dried by dehumidifiers, to flow in via the opened edge joints or other relief openings to balance the pressure again.
the same as vacuum!
In order to extract a certain volume of air, for example 100 m³ at a counter-pressure of 100 mbar (e.g. styrofoam, mineral wool), around 20 % more energy is required than to flood the damp course with the same volume of air at an identical counter-pressure (100 mbar). At a counter-pressure of 150 mbar (e.g. Perlite), the difference increases to 30 %.
Or to put in another way: A damp course drying unit using the positive pressure method can flood 20 to 30 % more air into the damp course than it can extract using the vacuum method under the same conditions!
Summary: depending on the method, the area performance of the vacuum method is lower than that of the positive pressure method.
Important note about the vacuum method:
In this method, the use of a filter is necessary so that, amongst others, no water or particles can get into the compressor. This would lead to blockage of the turbine and thus to destruction of the unit. Benefit from the advantages of the Trotec filter chain – for more information…
| Advantages and disadvantages of the methods in comparison |
Positive pressure | Vacuum |
|---|---|---|
| Danger of uncontrolled spread of water in not affected zones |
yes | no |
| Potential inventory damage and room atmosphere deterioration in adjoining areas | yes | no |
| Pressed-in moisture in edge/corner areas can lead to prolonged drying times |
yes | no |
| Area performance for identical machine use | 100 % | 80 % |
| General drying duration in relation | normal | faster |
| Mineral-dependent efflorescence in natural stone floors possible due to capillary pressure | yes | no |
| Warp damage in bitumen screed flooring possible | yes | no |
| Protection against contamination of breathing air by spores, allergens or suspected carcinogenic micro-fibres possible | no | yes |
| Number of necessary drill holes for air flooding openings |
more | less |
| Application in hygienic area such as hospitals, old peoples’ homes, schools, kindergartens, etc |
prohibited | yes |