hotte de captage

CONT: Receiving hoods are positioned to catch contaminants that are discharged from an operation in a predictable direction. Examples of receiving hoods include canopies located over a hot process in which hot exhaust fumes rise to the hood level by their own buoyancy, and hoods located adjacent to grinding wheels to catch the stream of dust generated by the spinning wheel. Receiving hoods may physically resemble capture hoods, but they differ with respect to the principle used for contaminant capture. Capture hoods operate at a higher flow rate to generate the air velocities necessary to capture contaminants from a source some distance from the hood opening. Receiving hoods, on the other hand, are positioned to catch the stream of contaminants delivered to them by forces intrinsic to the operation.
OBS: Hood designs can be placed into three broad categories based on the methods used to capture contaminants: exterior hoods, receiving hoods, and exhaust enclosures.