what is the little metal lip in my yoke valve?

[Bubba_in_cali]

hello. there seems to be a lip at the lower part of the circular opening to which I connect my regulator. While replacing the O-ring in here, I noticed that the circular opening is not perfectly circular. I have circled the flattish lip in green in the photo attached

Would you happen to know what that is? I don't see such a lip and my other cylinders. This is supposed to be in aluminum 80 ft.³ cylinder.

Thank you for your time.

bubba

 

[happy-diver]

https://static1.squarespace.com/static/55031996e4b0562b390e52e4/t/5a53bb9424a69443fdf71318/1515437015704/Thermo-Valves-Manual.pdf

 

[Zef]

-Z

 

[johndiver999]

Time for a toothbrush and vinegar

 

[happy-diver]

Not vinegar, but Phosphoric Acid

I have a brass bristled toothbrush

 

[happy-diver]

For the immediately gratified time poor, that shall no longer delve to learn more

View attachment 785509

-Z

 

[broncobowsher]

View attachment 785509

-Z

Interesting. At first I thought they had a rough service. Then I noticed they were all like that. Now I know why!

 

[Bubba_in_cali]

View attachment 785509

-Z

Got it, thank you Zef!

 

[Bubba_in_cali]

https://static1.squarespace.com/static/55031996e4b0562b390e52e4/t/5a53bb9424a69443fdf71318/1515437015704/Thermo-Valves-Manual.pdf

Thank you, happy-diver, I see on page 14 there!

 

[Bubba_in_cali]

Time for a toothbrush and vinegar

Oh yeah? Ok, will do, thanks johndiver999.