Passage-ventilation system for clearing fumes from drain

摘要

A first blower fan (2) is mounted at the mouth (5) of a first passage, and a second suction fan (3) is mounted at the mouth of a second passage (6). Each fan can be designed for use as a suction fan or blower. The blower fan can be mounted with its front towards the mouth of the passage, and the suction fan may be mounted with its motor towards the mouth of the passage. Adaptor rings (4) can be mounted at the mouths, these typically being stepped so as to give two different internal diameters. The smaller of these matches the external diameter of the front of the first fan and the larger that of the rear of the second fan.