Vapor Equalizing Valve

JB_8

It lets the air out of the pipe to let the steam in the pipe and heat the pipe up. This is a riser from the floor to the ceiling with the vent up at the ceiling?

Brian_45

Vapor Equalizing Valve

There is a silver nob on a pipe that says vapor equalizing valve. Any clue what this does? Is this a heating pipe or a hot water pipe?...I have steam heating in my apartment by the way. Thanks.