What is this air tank fitting?

[1190R]

Just bought a used 300 gallon air tank
What is this fitting?

 

[archtimb]

Antique barbed fitting?

 

[whateg01]

What is the diameter? Looks like an old fitting for plastic pipe

 

[Dodgepu360]

Looks like one of these to me

https://www.homedepot.com/p/Water-Source-1-in-Steel-Male-Insert-Adapter-MAS100/203990017

 

[1190R]

Thanks guys
ArchT was right
I thought it might be some kind of crazy valve but it's just a barbed fitting

 

[The Cobbler]

it's a reducing barb fitting x NPT .
the NPT is larger & the hose barb is smaller

 

[Firebrick43]

Does your tank have a legible ASME certified data tag on it?. If not, it is not a reliable air tank

With that fitting someone has been using it for something other than high pressure air.

 

[larry_g]

if it is hollow through then it is a hose barb.

 

[1190R]

Does your tank have a legible ASME certified data tag on it?. If not, it is not a reliable air tank

With that fitting someone has been using it for something other than high pressure air.

It does
Going to hydrotest anyway

 

[1190R]

I want to replace the barbed fitting with a double tapped bushing for an auto drain valve
Which one of these is better and why?

 

[whateg01]

Why do you need double-tapped? The auto drain only threads into the outside, right? At least the ones I've used have.

 

[OccupantRJ]

I want to replace the barbed fitting with a double tapped bushing for an auto drain valve
Which one of these is better and why?

Those are generally called reducing bushings. A drain will need to be on the bottom of the tank. Are you planning to lay that on it’s side? It looks like a vertical air receiver used in industry designed to stand on the mounting ring, so the drain would likely be on that end. I would also want a pressure relief valve at/in it somewhere. I hope you have a rather large air compressor with a decent duty cycle.

 

[Old Man Roger]

Looks like a propane tank.

 

[welder4956]

Looks like a propane tank.

That's what I was thinking, but it's not quite the same. What is the max pressure rating on that tank?

 

[1190R]

Those are generally called reducing bushings. A drain will need to be on the bottom of the tank. Are you planning to lay that on it’s side? It looks like a vertical air receiver used in industry designed to stand on the mounting ring, so the drain would likely be on that end. I would also want a pressure relief valve at/in it somewhere. I hope you have a rather large air compressor with a decent duty cycle.

Correct. Tank will lie on its side and yes. I got a 5 hp IR rotary screw air compressor
Relief valve present

 

[dr_clyde]

Looks like a propane tank.

That's an industrial air receiver, not a propane tank.

It is designed for what OP is doing.

 

[1190R]

That's what I was thinking, but it's not quite the same. What is the max pressure rating on that tank?

 

[micromind]

I want to replace the barbed fitting with a double tapped bushing for an auto drain valve
Which one of these is better and why?

In my opinion, neither one is better than the other. The difference is the manufacturers design preference.

 

[1190R]

In my opinion, neither one is better than the other. The difference is the manufacturers design preference.

Thanks Micro