What is this?

iix

Photos from a post on reddit

JUGHNE

A really neat air vent for some old "Off the wall(roof)" 2 pipe vapor system back when others would just stick the air vent into the chimney......some one here really knows. Should melt the snow around it.

Abracadabra

Some kind of steam controlled diaphragm valve? Found a "Western Kieley Steam Specialty Company" and pics of some similiar stuff but not much else.

http://www.ebay.ca/sch/sis.html?_nkw=1 2 600 KIELEY MUELLER 1456 ACTUATED PLUG VALVE&_itemId=201149671996

unclejohn

These guys don't know either.
https://www.youtube.com/watch?v=-l5tpY6SXMc