Ventilation of Huge Welding Shop

Abstract

A huge factory is ventilated with monitor roof, lots of roof fans, and/or natural ventilation. Welding shops at shipyard for construction of huge vessels are also conventionary ventilated. However, emitted enormous volume of fume during welding, the shop is poorly ventilated. In this report, some new approaches are developed on the idea of parallel ventilation current and effective exhaust: welding fume is traped in parallel ventilation current of the least air swirl as possible which is caused by ventilation facilities, and escorted to exhaust electric fans which are equipped on the wall of lower reaches of the current. One of the materializations of the idea is the upward ventilation current. Fresh air is supplied through many holes on holed welding floor to grow into parallel ventilation current which tend to roof, and welding fume is trapped in the current to roof ventilators without diffusion. This is effective because welding fume has the initial upward velocity, and found successful in Sakai Shipyard of this company. Another is the horizontal ventilation current. Air is accelerated by many electric fans at the regular intervals to grow into horizontal current which has enough velocity to able to catch welding fume running away upward. Hence, the current should have more velocity than the former because the direction of the current is perpendicular to that of fume. Performance and arrangement of electric fans might be designed using the velocity distribution and equi-velocity lines of the jet from electric fans which is calculated in the report.