Suggested upgrade for Welding Gas Cannisters

Metal Shop
#1

Saw these mentioned on the MakeZine site: it’s a $20 valve knob cover which visually and automatically indicates that the tank valve is open. It’s two nested caps: the inner one has red stripes, while the outer one has notches which allows you to selectively see parts of the inner cap.

When you open the valve, the outer cap first rotates relative to the inner cap, exposing the RED warning stripes. When you close the valve, the outer cap rotates back and covers the red stripes automatically as a part of the valve-closing process.

Provides an automatic and easily seen visual reminder that the tank is open. Seems like a good investment in preventing wasted gas due to a tank being left open for an extended period.

3 Likes
#2

I see 1 large issue and 1 smaller issue with these. First being safety, there is no function of the cap that stops it from giving a false positive if you manage to partially close the valve and the cap displays all yellow. Second, how do we keep track of our $20 valve caps if you have a scheduled cylinder refill program as in many cases they just switch out the cylinder taking your cap with it.

This is a cool idea, especially for the home shop where you can guarantee you did things the right way, but probably not for DMS from my perspective. Just my 2 cents.

#3

The swapout sounds like a legitimate issue: do the gas folks remove the tanks from the welders, or only from another location? Theses caps slip over the top of the existing valve handles - they don’t replace them - so if WE move the tanks to a swap-out location, moving these covers over to the new tank can be part of the swapout procedure.

re: your second (well, actually first) concern about false positives: I haven’t used them so I don’t know if they’ll swap from “open” to “closed” without closing the valve firmly: I could see designing the part to be “sticky” in the open position so that it wouldn’t move to the closed position until the valve itself was firmly closed and stopped moving in response to pressure. Thus, only slight pressure would be needed to “open” the indicator, but firm pressure would be needed to “close” it.

Could it work this way? Yes. Does it work this way? I have no first hand knowledge, but it would be prudent to do so to avoid such false positives.

#4

I can’t find much more on them. I see an issue is that you are supposed to open the bottles fully. Not sure if they take that into account.

1 Like
#5

I thought the same thing when I realized they were just a cap. But, I’ve also used rather tight valves at times when they have been opened with too much force. A situation like that would be an issue for even the sticky design. Having that failure condition a possibility does undermine this cap.

#6

Yeah, they don’t replace training. I think they are to prevent accidentally forgotten, open tanks.

1 Like