On the Elimination of Welding Fume by Ring Hood

Abstract

Various local exhaust apparatuses are applied to eliminate the welding fume for the purpose of improving the environment in welding shops. Nevertheless, these apparatuses do not always function, but it comes into question that the parts to be welded are hurt in the case of CO₂ gas welding method, on account of the reason that inflow streams of hoods disturb the shield gas atmospheres.
Therefore, the following are tried to solve above mentioned problem; that is, making the hood's opening ring form would be effective to prevent the disturbance of shield gas atmosphere and to raise the inhaling efficiency of hood.
From the point of view in this experimental study, the sizes of hoods, the distances between base metals and hood's openings and the suction flow rates are varied, and the fundamental characteristics of hoods aie investigeted.
Now, the results are summarized as follows.
(1) Generally speaking, enlarging the size of a hood, closing the distance between a base metal and a hood's opening and increasing suction flow rate improve respectively the inhaling efficiency of hood.
(2) Such defects as the creation of blow-holes and the lowering of penetration efficiency are partly observed in cases of smaller sizes of hoods.
As the consequence, it is cleared that a ring hood is very effective, but always the most suitable hood should be designed, considering welding methods, welding position and so on.