Finishing off-gas collection

Considerable amounts of fume have to be captured and extracted when using thermal separation techniques. The work area may be as enclosed as much as possible, but ensuring the freedom of movement and that the inhaled air supply of the worker can be assisted. Dust collection techniques during abrasive cutting and grinding are differentiated between stationary machines and hand machines. Rigid hoods are customary at stationary machines, partly in connection with partial housings. 

Collection of the dust takes place via extracting walls, roof domes, moveable hoods or extraction work benches. An effective aid when collecting emissions are hot-air curtains which direct additional air into the cabin. The additional air used may be cleaned recycled extraction air, in order to economise on heating energy. However, it should be noted, that a portion of fresh air will still always need to be provided from the outside. 

Reduction of diffuse emissions of metallic particles and dust. 

The collection and extraction of dust-laden off-gas consumes energy. 

Operational data have been given in Section 3.11 and show that emission from cutting, scarfing and welding (without off-gas cleaning) are low compared to those for fetding and shot blasting. 

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