History of LPI connections

[emoreira]

@emoreira I agree with your post with the exception of the quoted comment above. Yes, a leak can occur if the Schrader valve fails-but only if there is another seal malfunction or if the QD is not connected.

Self inflating of a bladder is caused by a malfunction in the inflator valve. It is worth noting that balanced valves, such as found in the Scubapro and Atomics inflators, are less prone to failure than the common inflator devices.

Hi Couv, Balanced inflator valves like Scubapro and the standard K inflator valve are the best choice. 100 % agree.
Inflator valves with a schrader valve inside, like Aqualung, Cressi, Mares and many others have 2 schrader valves in tandem. One in the hose, which is mantainded open while the hose is connected and a second one inside the valve which is actioned by the user to inflate the bladder. If this schrader valve brokes (usualy the small spring breaks owing to poor rinsing) this valve remains open or hardly closed and LP air keeps entering the bladder (self inflating). I mean the air leaks inside the bladder.
Inflator valves based in schrader valves, not only suffer from leaking schrader valves, but also I usually see plastic carriers (where the valve is threaded) broken owing to too much torque to screw in the valve. Again the bladder self inflates.
I hardly see any inflator hose with a broken schrader valve. This valve receives no water and works very litle.

 

[broncobowsher]

And higher flow is not always a better thing. I recall years ago they were doing tests of BCs holding the inflator button at the same time as the dump. If the inflator filled faster than the dump dumped, it was a fail.

There are nice things about an industry standard. Unless you are a very powerful player you will not change the standard, just alienate yourself from the market. Apple can set standards as they are such a big player. You really need to be that big to make changes. That standard BC quick connect works almost universally. Someone who owns a regulator set but rents a BC on vacation, it just plugs in. The dive shop with a large inventory of rental gear, just take two parts and they plug together. Add a drysuit, same connector. Even rebreather bailout use the standard BC connector.

The closest thing to a different standard would be some of the Omniswivel stuff. Even then it is still niche market stuff.

 

[emoreira]

And higher flow is not always a better thing. I recall years ago they were doing tests of BCs holding the inflator button at the same time as the dump. If the inflator filled faster than the dump dumped, it was a fail.

There are nice things about an industry standard. Unless you are a very powerful player you will not change the standard, just alienate yourself from the market. Apple can set standards as they are such a big player. You really need to be that big to make changes. That standard BC quick connect works almost universally. Someone who owns a regulator set but rents a BC on vacation, it just plugs in. The dive shop with a large inventory of rental gear, just take two parts and they plug together. Add a drysuit, same connector. Even rebreather bailout use the standard BC connector.

The closest thing to a different standard would be some of the Omniswivel stuff. Even then it is still niche market stuff.

I agree with the point that a dump valve should dump more volumen that what the inflator can inflate. Also for a Drysuit. But in the case of integrated octopus with the inflator, the standard DIN QD has not enough flow capacity to breathe at depth. Of course that an integrated Octopus and inflator, the flow to the BCD bladder shoud be restricted to what is needed, this is the dump capacity.

 

[broncobowsher]

I agree with the point that a dump valve should dump more volumen that what the inflator can inflate. Also for a Drysuit. But in the case of integrated octopus with the inflator, the standard DIN QD has not enough flow capacity to breathe at depth. Of course that an integrated Octopus and inflator, the flow to the BCD bladder shoud be restricted to what is needed, this is the dump capacity.

Agree. I was just pointing it out as the OP was doing research on inflators. Figured that was a detail that should be included.

 

[Gone for diving]

I can't think on what I have seen it,,,
but I am quite sure I have seen an M style air fitting used...
Maybe it was something someone butchered on, and wasn't factory,

In those applications, that valve is sparsely used, not like in a BCD inflator valve, which is oftenly used, much more in a BCD used by a dive school. This leads to premature inflator valve malfunction (leaks and/or bladder self inflating).

I don't think the sharder valve is the weak point in this quick connect, hooked up it sits open, it can only leak when disconnected from the Male fitting, (usually the oring leaks instead )
And if a shrader valve leaks its usually a slow leak that will not effect your dive,
(It means your bcd or drysuit hose is not connected), It's amazing how reliable a shrader really is, On AC systems its usually a very tiny leak the needs soapy water to see,
And theoretical on a reg set, a shrader valve rubber seal never sees dirt or water at the sealing surface, even underwater,

Now if a shrader valve is used as a bcd inflator button, that can be more problematic...

 

[broncobowsher]

I don't have anything setup to try it at this time, but I am pretty sure you could completely remove the schrader valve from the quick connect and it will work just fine so long as it stays connected. The schrader valve is only there to stop the airflow when the hose is not connected.

 

[emoreira]

I can't think on what I have seen it,,,
but I am quite sure I have seen an M style air fitting used...
Maybe it was something someone butchered on, and wasn't factory,




I don't think the sharder valve is the weak point in this quick connect, hooked up it sits open, it can only leak when disconnected from the Male fitting, (usually the oring leaks instead )
And if a shrader valve leaks its usually a slow leak that will not effect your dive,
(It means your bcd or drysuit hose is not connected), It's amazing how reliable a shrader really is, On AC systems its usually a very tiny leak the needs soapy water to see,
And theoretical on a reg set, a shrader valve rubber seal never sees dirt or water at the sealing surface, even underwater,

Now if a shrader valve is used as a bcd inflator button, that can be more problematic...

You are saying exactly the same of what I've written.

 

[LPI researcher]

The responses here are fantastic, thank you all!

 

[rjack321]

The larger bore QD used in Octo integrated Power Inflators, like Air2, TUSA Duo Air and others, or many Drysuits inflator valves, are the CEJN QD
Inflator hoses with DIN size QD use the standard schrader valve. Also many inflator valves use schrader valves. Schrader valves, as mentioned are used for car tires, Air Conditioning inspection valves, etc. In those applications, that valve is sparsely used, not like in a BCD inflator valve, which is oftenly used, much more in a BCD used by a dive school. This leads to premature inflator valve malfunction (leaks and/or bladder self inflating).

The schrader valve is a male valve (the pin) inside of a female hose end. The valve itself opens as soon as it's attached to the nipple. It's open throughout the dive and a failed open schrader valve does not lead to a self inflating wing at all. They can fail closed or get stuck closed, but generally speaking in that case you can't get the nipple into the female hose end in the first place. A self inflating wing from a leaking power inflator is failing from the button oring which are quite a bit downstream of the hose end.

The oring in the female side of the hose fitting is not actually part of the schrader valve itself.