Flat cross=section venting pipe - has trapezoidal form with rounded corners, being dimensionally wider horizontally

摘要

The pipe is for a venting or ventilation conduit and particularly for use with a fume-extraction cowl. The pipe cross-section has a horizontal base which is longer than its height. The height of the cross-section at one side is greater than at the other. The top surface (28) can run at an acute angle to the base (24), or it can be in two straight sections, one of which at least is at an acute angle to the base, while the other is parallel with the latter.