Plumbers? Steamfitters?

[lptools]

Hello, Are there any plumbers, or, steamfitters here? I am guessing these are plumbing, or, boiler related. Any idea what these are called, or, used for?? Thanks, Lou

[p_toad]

Looks like an E clip on the one.   Are the plugs removable?   Appear to be max temp limiters to me, but i'm not a pipefitter.   

[Chillylulu]

Are there small tubes coming iff tge back side?

We used to use similar hollow vessels on mercury check rate-of-rise systems. H.A.D.'s or heat activated devices.

Chilly

[lptools]

Hello, Guys. Good eye on the clip, but that is the only one of about 10 that had the clip. The threaded end appears to be lead filled,and the discs appear to be sandwiched. I will try later to get one apart. Thanks, Lou

[oldgoaly]

I'm gonna say for steam or hot water, thermostatic control valve. There will be a glycol or some type of fluid in the diaphragm.
At the local foundry casting class there was one in the brass crucible to be melted. I saw it just had a bad feeling. So instead of starting up the furnace and melting the brass in the pot I took the valve apart. Yep diaphragm was filled with a fluid.

[lptools]

Hello, Oldgoaly. I think you have it!!!  Here is a link to what you described. I am still guessing, but I think what I have is a replaceable part of a valve. I heard the fluid moving in the large one. Thanks, Lou

[lptools]

Hello, Oldgoaly. Thanks again for the info. I found a good picture of what I have. After all the things I looked at, there is one on ebay!!!!!   Item No. 28261457180