When blasting parts dust is created on the surface of the material being treated. This occurs during processes such as de-scaling, deburring, surface finishing (e.g. texturing, polishing) and parts cleaning (removal of rust, sand, paint and contaminants).
Dust is generated by blasting abrasives such as iron, stainless steel shots or a variety of granulate material. For a clean and safe work environment, the dust must be thoroughly extracted and separated from the air.
When selecting an extraction system, it is necessary to take into consideration both the dust characteristics as well as your individual requirements (i.e. constantly growing product quantity at high blasting quality versus a declining efficiency). There are two categories for considerations:
Blasting processes have a high risk of producing sparks from the shot material. This spark, combined with combustible process material, can create a high risk for fires. These risks can be mitigated by utilizing a spark pre-separator or automatic fire suppression system for a dust collector system. The risk can be completely removed by utilizing a wet scrubber dust collection system.
Depending on the material being processed and the dust generated, an explosive material could be collected within your air filtration system, which requires explosion protection measures. To identify the material safety risk the collected process dust (or representative sample) should be tested for explosion characteristics. This helps to determine the components for explosion protection necessary to install on a dry dust collector. This risk is eliminated by utlizing a wet scrubber dust collector.
Determining whether to recirculate the exhaust air in the facility (versus exhausting outside) is a factor that affects the appropriate efficiency of the filter technology and media chosen. Additionally, abrasive material in the blasting process can damage the filter media, if the necessary precautions are not taken, and dust particle emissions may be returned to the air.
The quantity of material and the level of abrasiveness helps determine the appropriate pre-separation process necessary to effectively exhaust particulates. Types of pre-separation include:
Inlet Deflector: A deflector at the inlet to the dust collector to protect the filter media from damage from the abrasive material
Cyclone: High efficiency separation by a reinforced cyclone to withstand the abrasive material and separate out larger particulates to reduce the load on the dust collection system
Drop-Out Box: Drop-out box to separate any larger shot that is pulled from the process. This shot is collected for reuse once separated from the air stream
The quantity of dust generated in the process and the amount of interaction/handling by personnel has a large impact on the disposal. Examples of available disposal methods include:
Level Sensors: any disposal option can also be upgraded with a level sensor to monitor and indicate the fill level of the disposal container
Sludge Conveyer: for automatic disposal of wet scrubber systems
Drums/Big-Bags with Rotary Lock: for high volume disposal and on-line disposal
Drums: for higher volume disposal
Buckets: for lower volume disposal