Regulator and Tank Valve Terminology

[OMyMyOHellYes]

There is no such thing as a 3rd scuba stage, unless it's some really esoteric system. There may be a second, second stage reg, but not a third stage.

"Stage" refers to the function of reducing the HP side from the bottle in steps. First pressure reduction stage brings HP down from 3000-3500 down to the IP of say 120-150ish. Second stage brings the IP down from 120-150 to ambient pressure. There is no stage reducing pressure below that. I suppose somebody could introduced an intermediate intermediary stage but that would be silly.

Compressor systems often run three or even four stages to step up the pressure to get to the bottle's service pressure.

 

[OMyMyOHellYes]

A "K valve" can be "Yoke/International" or a DIN Valve.

A K valve can never be a DIN valve in the strict sense of the word.

Tank valves from the era in which the terms "K" and "J" evolved were both yoke valves; K valves were simply on/off where the J valve held an intermediary reserve pressure that had to be release to use on the way up. While DIN valves may be "binary" on/off, I have not ever seen them in the old Aqualung catalogs whre the "K" reference originates.

 

[lexvil]

Some shops doing reg rebuilding are charging " per stage ' and separating out labor and parts cost on different customer invoice lines. So they list 1st stage, 2nd stage, & 3rd stage. It helps their computerized inventory and subtracting the correct parts kit SKU numbers for on hand and reordering.
Not that it's right/wrong/correct,,,,,,it's just helps when a customer asks why they are being charged for two 2nd stages on the invoice.

That does explain it, I prefer the Bob Newhart version, this is my second stage Darrel and thins is my other seconds stage Darrel.

 

[lowwall]

Really confusing and it seems the tank valves are DIN and K but a “Yoke” adapter is necessary to use DIN 1st stage on K valve.

This is incorrect.

First let's deal with the K. Virtually all scuba tank valves sold today are K valves. K just means that it doesn't have a lever activated "reserve" function.

BTW, it's not really a reserve. "J" valves had a spring-loaded mechanism that shut off the air at a few hundred psi of tank pressure. Pulling a lever defeated the mechanism which allowed you to breathe the remaining air in the tank. These date to the days before the SPG was a standard part of diving equipment so it was useful to have a warning that you were low on air.

Getting back to today. K valves are available in DIN only, yoke/international only, or a combination that takes either via a screw-in flush fit adapter piece.

Finally, there are adapters that can be screwed on to a DIN first stage to make them compatible with a yoke valve, but at the cost of making the reg stick out further and making the whole system a bit less reliable.

 

[lowwall]

A K valve can never be a DIN valve.

Tank valves from the era in which the terms "K" and "J" evolved were both yoke valves; K valves were simply on/off where the J valve held an intermediary reserve pressure that had to be release to use on the way up. While DIN valves may be "binary" on/off, I have not ever seen them in the old Aqualung catalogs whre the "K" reference originates..

Except that the terms K valve and J valve have long been used in the generic sense.

For example: Thermo Pro DIN/K Modular Valve, Right (Typical Side)

 

[BoltSnap]

A K valve can never be a DIN valve.

Incorrect

 

[OMyMyOHellYes]

Except that the terms K valve and J valve have long been used in the generic sense.

For example: Thermo Pro DIN/K Modular Valve, Right (Typical Side)

Widespread usage does not make something right. A photocopy is not necessarily a Xerox, a facial tissue is not necessarily a Kleenex, a parking apron or ramp at a large commercial airport is almost never likely to be Tarmac. See also the widespread use of the term "clip" when one is really referring to a magazine.

Incorrect

No, I correctly said you incorrect.

 

[jborg]

Widespread usage does not make something right. A photocopy is not necessarily a Xerox, a facial tissue is not necessarily a Kleenex, a parking apron or ramp at a large commercial airport is almost never likely to be Tarmac.

Did Aqualung trademark the term "K valve"? Can only valves manufactured by Aqualung be called K valves?

 

[OMyMyOHellYes]

Did Aqualung trademark the term "K valve"? Can only valves manufactured by Aqualung be called K valves?

Actually, you would be correct. Only those from the original catalog would be "K" valves. So we would be referring to K-like valves.

I got up and put on my pedantic pantalones this morning.

Given single-mode valves' almost universal, ubiquitous nature, the term "valve" generally suffices. It is the base valve. Any deviation from that configuration/binary function would be where the qualifier would come in (modular, H, Y ...). The standard valve has three widely used types: DIN (200 and 300 BAR - even that 200 BAR reference is an incorrect nomenclature), yoke/internationa/A, and convertible/pro configuration. Some standard 200 BAR DIN cannot be used with the screw-in ring converters, thus the third configuration.

 

[CRT2]

From Sherwood SCUBA :

Sherwood Valves are the most used valves in diving. Sherwood Valves can be found on cylinders on every continent. The critical link between your regulator and tank, our patented Sherwood valve was designed specifically to handle today’s high-performance regulators. Sherwood valves are available in both Pro Valve (DIN/K) and K Valve.