Dust and Fume extraction

Dust and fume extraction is commonly used in industrial applications to either reduce environmental emissions or reduce occupational exposure for people working in an area. The purpose of fume and dust extraction is to remove the fume and/or dust from the hazardous source location and extract it to another location where it can be collected or dispersed so that it is no longer a hazard.

Different Types of Dust and Fume Treatment 

The decision on how to treat the extracted dust or fume depends on its quantity and how hazardous it is. Examples of possible treatments are listed in the table below.

Description	Possible Treatment/Fume collection device
Welding fume	Extract the fume away from operator and disperse fume outside to atmosphere.
Laboratory fume cabinet	Extract fume and disperse to atmosphere
Dust from a conveyor transfer point	Extract the dust from the transfer point and capture the dust with a bag house dust collector.
Dust from laboratory pulveriser	Extract the dust from the transfer point and capture the dust with a bag house dust collector.
Fume from smelting equipment	Extract the fume and/or dust from the working area and capture with a wet scrubber.
Dust from a woodworking facility	Extract the dust and capture with a cyclone dust collector.

Capture Velocity

Transport of the dust and fume from the source is done by creating sufficient air velocity to initially draw the fume into the capture hood attached to the ductwork and then keep the dust and fume particles airborne while traveling in the ductwork until they reach the equipment capturing the dust or fume. Often a single collection device, such as a dust collector or scrubber, will be used to collect dust or fume from several different points within one area, resulting in multiple ductwork branches off a main duct. It is critical that each individual duct has sufficient velocity to keep the dust or fume airborne in the duct to prevent settling out. For this reason, it is critical that the entire ductwork system is designed and sized (balanced) to match the performance of the extraction fan and ensure that each individual duct is achieving the design duct velocity. The use of dampers to adjust flow in the duct should be avoided, as any adjustment to the flow velocity in one duct branch will unbalance all the other duct branches, resulting in performance deficient. Balancing flows between the individual ducts can be achieved permanently by sizing the lengths and diameters of all the individual ducts to get the required pressure drop during the design stage.

Rapallo Capability

Rapallo has experience and capability to completing engineering design of dust and fume extraction systems, along with the specification and selection of appropriate fume and dust extraction equipment from vendors. If you have a new system you are looking to install or you have an existing system that is not performing as it should and you want it assessed, please contact Rapallo to discuss further. To see more about Rapallo’s design capabilities, visit our website at Engineering & Projects | rapallo.com.au.