Source Capture Filtration Systems
Source capture systems fall into several categories, each designed for different purposes. The correct solution will depend on the application (e.g., manual welding, robotic welding, cutting or grinding).
- Overhead Hoods: Hoods are generally the best solution for robotic or laser welding applications. Welding fumes are contained within the overhead hood, keeping them out of the ambient air in the facility and making them easier to collect. Overhead hoods can be configured to contain one or more welding operations. Overhead hoods are sometimes also used with manual welding applications. However, they do not keep weld fumes out of the breathing zone for the welder, so they must be combined with another source capture system or personal protective equipment for the welders inside the hood.
- Fume Guns: Fume guns are a two-in-one welding gun and fume capture device that extract the contaminants as soon as they are created. Because the extraction is occurring right at the welding arc, it is always positioned correctly for maximum extraction efficiency. Fume guns work well for welding applications where the welder is highly mobile and it is not practical to use a fume arm—for example, large pieces that require welders to crawl over the equipment or use lifts, or welding inside equipment such as tanks or ship hulls. Older fume guns tended to be bulky and reduce visibility for welders, so many welders have resisted using them. However, newer fume guns like the RoboVent Extractor are smaller and lighter so they are more comfortable to use and maintain good visibility of the weld seam.
- Fume Arms: Fume arms are movable suction devices that are manually positioned over or near the weld arc. They are used for manual welding applications. Used correctly, they are highly efficient (roughly 95%) at capturing fumes in their immediate vicinity. Because they are so focused, they require relatively little airflow, making them an energy efficient capture solution. However, they must be continually repositioned as the welder moves in order to maintain their capture efficiency. Fume arms work best for smaller parts that are very size-consistent and remain stationary on the bench, reducing the need for manual repositioning of the arm.
- Backdraft/Sidedraft Intake Plenum: This system consists of inlet or grill connected to the main ductwork system and mounted behind or beside the welding zone. It is best suited for bench or fixture welding applications with larger parts of fairly consistent size and placement on the bench or fixture. Unlike fume arms, there is no need for the operator to adjust anything; the air intake is always in the correct position. The backdraft/sidedraft plenum must be sized for the largest possible part that will be welded in front of or beside it. It uses more airflow, and thus more energy, than a fume arm.
- Downdraft table: Downdraft tables are most often used for cutting and grinding applications. Unlike thermally generated weld fumes, which rise, dust created by cutting or grinding falls out of the air. A downdraft table assists gravity with a downward airflow that pulls particulates out of the air and into a collector.