Internal threads on CO2 tank fitting

[rnorman57]

I had a 5 lb CO2 tank refilled today, and I happened to notice the fitting has internal threads. Anyone know what these are for? The outside threads are standard CGA 320.

 

[hotbeer]

Anyone know what these are for?

A different type of connection than what you have. That way it will work for both you and for someone else that has the other type connection.

Propane cylinders are the same way. I have a grill that uses the external threads of the bottle to make the connection. And a space heater that uses the internal threads to make a connection.

 

[bracconiere]

that's the filter threads for the cancer chemicals...california requires all co2 tanks to be rifled to put a spin on the gas!

looks kinda like the fittings that are on a regulator for the gauges, output, and arm to hook up to the tank?

 

[day_trippr]

Just gonna drop this here...

https://www.amazon.com/Leak-Stopper-Permanent-Ring-Cylinders/dp/B018UNZLHU

 

[rnorman57]

A different type of connection than what you have. That way it will work for both you and for someone else that has the other type connection.

Propane cylinders are the same way. I have a grill that uses the external threads of the bottle to make the connection. And a space heater that uses the internal threads to make a connection.

Yes, unfortunately I'm old enough to remember when the internal (POL I think they are called) threads were the only way to connect to a propane tank. I still have a burner that connects that way. Obviously the internal threads are for a different type of connection...thanks.

 

[day_trippr]

POL threads on a propane cylinder are hella wider bore than the hole in a cga320 valve.
I wouldn't want to try hanging a regulator off those threads...

 

[rnorman57]

that's the filter threads for the cancer chemicals...california requires all co2 tanks to be rifled to put a spin on the gas!

looks kinda like the fittings that are on a regulator for the gauges, output, and arm to hook up to the tank?

Yes, the outer threads are for the typical regulator connection. I was just curious if the internal threads were for some other purpose.

 

[rnorman57]

POL threads on a propane cylinder are hella wider bore than the hole in a cga320 valve.
I wouldn't want to try hanging a regulator off those threads...

Ok. I don't get why the comparison

 

[bracconiere]

I was just curious if the internal threads were for some other purpose.

possibly the valves are standard, and if the tank had a dip tube something like this?

https://www.aliexpress.us/item/3256...irect=y&gatewayAdapt=glo2usa&_randl_shipto=US
(edit: didn't notice that was aliexpress)

 

[Misplaced_Canuck]

A different type of connection than what you have. That way it will work for both you and for someone else that has the other type connection.

Propane cylinders are the same way. I have a grill that uses the external threads of the bottle to make the connection. And a space heater that uses the internal threads to make a connection.

The outside threads are the "new" threads, the inside are obsolete. Eventually they will be removed.

 

[day_trippr]

The outside threads are the "new" threads, the inside are obsolete. Eventually they will be removed.

Every propane fill station I've ever used used the POL threads. I'd be surprised if that ever changes...

Cheers!

 

[Misplaced_Canuck]

Every propane fill station I've ever used used the POL threads. I'd be surprised if that ever changes...

Cheers!

For now it does I haven't seen a single grill that uses the internal threads in a long time.

 

[day_trippr]

The dual-stage high-flow regulator I use on my propane brew rig is POL-type, but it's also adjustable, not something you'll find on a BBQ

Cheers!

 

[Deadalus]

I have an adapter for my portable grill that uses the interior threads. The grill is setup to use the 1lb propane bottles. Confused the hell out of me because I had never seen a grill hooked up using that connection.

Maybe the CO2 tank is filled up with the interior threads similar to how propane tanks are as mentioned by day_trippr.

 

[day_trippr]

Not a chance wrt CO2 cylinders. That inside thread on the cga320 valve shown is strictly there for accessories...

Cheers!

 

[rnorman57]

So nobody really knows what the internal threads are for, other than "a different type of connection".

 

[Dr_Jeff]

So nobody really knows what the internal threads are for, other than "a different type of connection".

See post #4

 

[hotbeer]

See post #4

I doubt the original intention was just for giving more life to a banged up mating face.

I'd ask the people where the tank is filled. Might be more for people on that end of the business to use than for the consumer to use. Maybe a older type hookup. Possibly to connect many tanks together and use in a manifold cascade system.

 

[Dr_Jeff]

I doubt the original intention was just for giving more life to a banged up mating face.

I'd ask the people where the tank is filled. Might be more for people on that end of the business to use than for the consumer to use. Maybe a older type hookup. Possibly to connect many tanks together and use in a manifold cascade system.

What that is, is a seal so that one doesn't need the fiber or plastic gaskets..

 

[Cider Wraith]

Yup ...

 

[day_trippr]

fwiw, best as I can tell the cga 320 valve specification does not require those internal threads.
And I can find valves being sold that don't have them...

Cheers!