vent pipe

noun Plumbing.

a pipe above a waste pipe or soil pipe that allows gas to escape from the system.

Origin of vent pipe

First recorded in 1855–60

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Typical simple forms of vent-pipe suitable for acetylene apparatus are shown in Fig. 7.
Acetylene, The Principles Of Its Generation And Use
F. H. Leeds
It is indispensable that every acetylene apparatus shall be fitted with a safety-valve, or more correctly speaking a vent-pipe.
Acetylene, The Principles Of Its Generation And Use
F. H. Leeds
Nevertheless this form of vent-pipe produces a gurgling noise, and would be better for a trumpet-shaped mouth.
Acetylene, The Principles Of Its Generation And Use
F. H. Leeds
So tall a vent-pipe, however, seriously raises the centre of gravity of the bell and may make it top-heavy.
Acetylene, The Principles Of Its Generation And Use
F. H. Leeds
No water enters the vent-pipe from the holder, and therefore no gurgling or irregular pressure is produced.
Acetylene, The Principles Of Its Generation And Use
F. H. Leeds