During an audit of an apartment building in N. Wisconsin that started life as a high school built in 1908, I found this very strange cast iron - steel device up in the floored attic. Anybody have any idea what it is??
The whole thing is about 2 feet tall and weighs 75 pounds or more. The bottom two-thirds (straight sides) is a tube made out of thick cast iron, and it looks a lot like cast iron sewer pipe. (And yes, the building does have cast iron sewers and sewer vents.) And, as you can see when looking at it from the bottom, inside the tube of this lower portion there are two spiral fins.
The bulbous top portion is thinner -- I think it's not cast iron but heavy sheet metal, like 12 or 10 gauge. I didn't look closely enough at the fitting in the bulb -- I do not know whether it's threaded to accept an NPT pipe nipple or not. I was, after all, supposed to be working on auditing the building...
I don't even know for sure that it's a building component, but I think it is. (It could be part of some wierd 1920s high school science demo. Maybe the Mad Scientist HS teacher performed unspeakable "experiments" up in the attic!) The building is fairly small, maybe 7,000 square feet per level, two stories tall with a full basement and a walk-up stairway to the floored attic above. The walls of the orignal building were triple-wythe brick. The chimneys (for the long-decommissioned boilers) are all conventional brick, so I don't think this is a smokestack cap.
It appears to be an early "flush" toilet. I've seen two very similar devices in turn-of-the-century homes, one in a basement alcove and one in a "shed" attached to the rear of the house. They both had water valves with a pipe angled into the bowl. It doesn't appear that it was connected, but just sitting in the attic, so likely just placed there rather than throwing it away.
Looks like the base of an old water tank, I've found some old water tanks in attics of pre-1900 buildings that were used to maintain good watre pressure before municipal water systems were available. Any other guesses out there ?
Looks to me like the top of a steam relief vent used to terminate the top of the vent pipe from a boiler feed unit receiver or pressure relief valve. The top was designed with a drain you can see on the side, this kept it clear of ice. The bulb top was jacketed so steam filled it, warmed it and kept ice from forming in the bowl, so it did not plug the next release.
One company that made them was Marshalltown out of Iowa. Look for that on the casting. These are collectable to some pack rats :)
I have searched Google Images for a photo of a similar device and I have one photo at work from a 1936 High School north of Boston. May post that if I can find it to show it "in place".
You may also see these on old steam tug boats, often a relief pipe running up the side of the boiler smoke stack. This is the bulbous object at the top of these vents.