2.2.4 Damp blasting
When using the conventional damp blasting method water or vapour is injected in small quantities, 30 kg/h at most, into the blasting hose.
This water mist being distributed most finely encases the blasting grain. When the grain that is accelerated by the nozzle impinges on the surface the dust generated by bursting is bound by up to 95%.
The injection pressure required to wet the dry abrasive compressed-air stream amounts to a maximum of 35 b. The amount to be injected can be adjusted according to the dust volume.
In case of vapour wetting the compressed-air/abrasive stream is heated additionally so that the surface dries immediately after the impact of the wet abrasive. This mainly avoids deposition of sludge residuals on the surface. The vapour causes the chlorides and sulphates being in the mains water to be removed. By this, metallically polished blasted steel surfaces tend to renewed surface oxidation only much later compared to damp blasting with water.
Schematic presentation of damp blasting
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- Table of contents
- 1. Fields of application of abrasive blasting technology
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2. Blasting technology
- 2.1 Airless blast cleaning
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2.2 Injection blasting
- 2.2.1 Compressed air blasting (also air blast cleaning or sand blasting)
- 2.2.2 Pressure blasting (injector blasting)
- 2.2.3 Vacuum-compressed-air blasting and vacuum injection blasting
- 2.2.4 Damp blasting
- 2.2.5 Wet blasting
- 2.2.6 Slurry blasting
- 2.2.7 Ice Blasting
- 2.2.8 Water- jetting cleaning and hydro-jetting
- 2.2.9 Wet blasting for fine surface treatment
- 2.2.10 Combination of different blasting methods
- 2.3 Laser cleaning
- 3. Abrasive
- 4. Efficiency assessment of abrasive blasting
- 5. Influence of compressed-air blasting on the surface of the workpiece
- 6. Generation of compressed air
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7. Plants for compressed-air blasting
- 7.1 Small and medium-sized blasting pots
- 7.2 Large blasting pots
- 7.3 Double-chamber blasting pot
- 7.4 Mixing and dosing valve
- 7.5 Hoses, lengths of hoses, couplings
- 7.6 Selection of a blasting pot in considering the wear and tear behaviour
- 7.7 Increased wear and tear at the blasting pot caused by wrong adjustment
- 8. Remote control and emergency shut-downs
- 9. Jet nozzles
- 10. Stationary blasting halls
- 11. Mobile abrasive blasting equipment
- 12. Laws and provisions