Plastic Insert in Corny Keg Gas Dip Tube?

[Brushwood Brewing]

I picked up a used corny keg this morning and am cleaning it out. In the gas dip tube, there's an orange plastic insert. See below photo (where the insert has been taken out of the dip tube). I've not seen this in any of my other kegs. A few questions:

1. What is the purpose of the insert?
2. If I remove the insert, but keep the existing gas dip tube, will everything still function properly with no leaks?
3. If I purchase a new gas dip tube without an insert, will it work properly with the existing ball lock gas-in fitting? Or is the ball lock gas-in fitting specially made to fit with this insert?

I don't trust the insert, since it's plastic and has probably been sitting in this uncleaned keg for years, so I want to get rid of it regardless.

Thanks all.

 

[day_trippr]

That is actually the gas dip tube. I have a keg like that one. I shortened it to ~1/2" total length just as I've shortened the stainless steel gas tubes on my other 15 kegs. I've never seen a combination of steel and plastic gas dip tubes on any corny keg. I'm guessing someone drilled out the riser to use a steel diptube then discovered something didn't work as expected.

It is necessary to have a gas dip tube to carry the small O-ring under it's flange that seals both the dip tube and the gas post to the threaded riser. You can replace that one with a new tapered tube like the original, here:

https://www.chicompany.net/diptubes-c-376_1_493/diptube-plastic-beveled-p-3344.html
Cheers!

 

[day_trippr]

Thinking about the possibilities a bit more I'm wondering if someone just stuck the plastic dip tube inside the steel one for some random reason and it's not actually needed. Indeed, no doubt if there's a small O-ring involved at all it clearly would be applied to the outer, steel tube, and that's doing all the work while theoretically the plastic tube is just going along for the ride.

Certainly worth an experiment: leave the plastic tube out, make sure you do have that small dip tube O-ring in place on the steel dip tube, put the gas post back on, charge the keg up with at least a few psi, then flip it over in a sink full of water and see if there are any bubbles streaming out of the gas post area...

Cheers!

 

[Red over White]

Is it a 10 gal corny, race track lid?

 

[Brushwood Brewing]

Is it a 10 gal corny, race track lid

No, just a 5gal with standard lid.

@day_trippr Interesting. Thanks for the link. I'll give that a shot, just removing the plastic insert. Yes there was an O-ring on the steel dip tube; I'm going to replace all the O-Rings anyway.

 

[odie]

strange.

The gas dip tube's only purpose I believe is to hold the o-ring in place and give the poppet's feet something to rest on so as to not tear the o-ring. It can be as short as 1/8-1/4 inch probably and function just fine. It's probably usually longer so as to be handled easier and/or not get lost.

One of my kegs came with just a plastic dip tube. But it was not a plastic tube inside a metal one.

 

[day_trippr]

I bet the original gas dip tube length was sized as a filling indicator. If I had an untrimmed original for any of my 16 kegs I'd test that theory.

Otherwise, you're right, they just need to be long enough to hold an O-ring and stay in place on the threaded riser while the post is screwed down. I cut all mine to ~3/8" including the one plastic dip tube I have...

Cheers!

 

[Brushwood Brewing]

I simply removed the plastic insert and replaced the o-ring (with a standard size). It seems to be working fine. Thanks all.