FILTER TESTS with the aid of a DUST TUNNEL

The Fram dust tunnel is a room 50 ft. long by 15 ft. wide, by 13 ft. high. A 200,000 cu. ft./min. blower is mounted slightly below floor level in one end of the room. It is driven by V‐belts from drums located transversely across the room, the drums being driven by the rear wheels of the car.