External air inlet to boiler house - has larger top pipe section forming annular gap with bottom one

摘要

The inlet delivers external air into a room, particularly combustion air into a boiler house, and has an upright length of pipe with a wind cowl. The pipe is in two or more coaxial sections one above the other. The top one (7) is sufficiently larger than the bottom one (8) to leave an annular gap between them. The cowl (9) can have one or more axial partitions (11) protruding into the top pipe section, the lower edge (12,13) of each including an acute angle with the pipe axis.