Argonaut Kraken "Volcano Orifice" Adjustment?

[Nemrod]

As I remember, it adjusts the distance between the orifice and the seat. There is a complication in that the rotation also disturbs the alignment of the internal airway, thus the limited adjustment range before airflow is cut off. I found no perceivable difference in ease of breathing due to the adjustment.

The orifice has a hole through it that does align with the air passage. However, the machine part is also relieved such that air can flow around the part. I never noticed any difference, perhaps at great depth, maybe. I can assure you that if the orifice is backed out, say a half turn or more, you can notice a restriction in air flow but that is not due to the passage alignment.

Initially Bryan was adjusting the orifice much as we would an orifice in a G250 or 109 to stop the hiss and the setting lever height. He had turned the orifice inward until the orifice knife edge made contact with the soft seat and flow stopped. That is incorrect. The orifice should be set flush (on the exterior) and adjust your lever height from the inside as always.

I was sent, very early on, a prototype Kraken by Bryan to use and test. I of course jumped in the pool with it right away, also took it on a long Florida trip and used it extensively. I immediately noticed on the first pool dive that something was amiss, it just would not give me any air. I spoke to Bryan and he was explaining to me how he adjusted the regulator. Hmmm. I tore it down to pieces but immediately came upon the problem, the orifice was set too low at least a full turn proud of the exterior surface. It has been so long ago now but I think I spoke with Luis afterwards also for his recommendation, anyways, I reset the orifice flush and all was well, went on my trip and used the Kraken every dive with no further problems. Second hand, maybe urban legend, but I think Luis told Bryan, the Kraken is not a Scubapro, do you see Scubapro engraved on it anywhere ? I am sure that Luis will come along and correct all of my errors and explain how it really was . I miss Bryan .

 

[Luis H]

The orifice has a hole through it that does align with the air passage. However, the machine part is also relieved such that air can flow around the part. I never noticed any difference, perhaps at great depth, maybe. I can assure you that if the orifice is backed out, say a half turn or more, you can notice a restriction in air flow but that is not due to the passage alignment.

Initially Bryan was adjusting the orifice much as we would an orifice in a G250 or 109 to stop the hiss and the setting lever height. He had turned the orifice inward until the orifice knife edge made contact with the soft seat and flow stopped. That is incorrect. The orifice should be set flush (on the exterior) and adjust your lever height from the inside as always.

I was sent, very early on, a prototype Kraken by Bryan to use and test. I of course jumped in the pool with it right away, also took it on a long Florida trip and used it extensively. I immediately noticed on the first pool dive that something was amiss, it just would not give me any air. I spoke to Bryan and he was explaining to me how he adjusted the regulator. Hmmm. I tore it down to pieces but immediately came upon the problem, the orifice was set too low at least a full turn proud of the exterior surface. It has been so long ago now but I think I spoke with Luis afterwards also for his recommendation, anyways, I reset the orifice flush and all was well, went on my trip and used the Kraken every dive with no further problems. Second hand, maybe urban legend, but I think Luis told Bryan, the Kraken is not a Scubapro, do you see Scubapro engraved on it anywhere ? I am sure that Luis will come along and correct all of my errors and explain how it really was . I miss Bryan .

I highlighted in bold a very true statement.

The orifice is adjustable, but it is not normally necessary to adjust it, to get a cracking effort of around 0.6 inWC to about 0.7 inWC. Adjusting the orifice will change the second stage spring pressure a little, but again, it is not normally necessary to adjust it. There is so much mechanical advantage with the lever and the large diaphragm that the slight change in second stage spring pressure is barely noticeable.

As @Nemrod mention, the orifice travel is limited. It can be unscrewed (outward rotation) only about 1/2 a revolution without restricting flow. On the inward rotation (increasing spring pressure) it can go more that a full revolution, but there is never a need to do that.

Again the preferred setting is with the back of the screw flush (or very close to flush) with the body and the screw slot lined up with the center dot (or at least in between the two outer dots). Therefore, the adjustments should be limited to + or - half a revolution. Once again, this is not normally needed.

To finely tune the cracking effort I normally just adjust the IP. I find it that between 125 psi to 135 psi it provides the best cracking effort of about 0.6 inWC.

I have easily adjusted the cracking effort lower than that (as low as 0.2 inWC), but that serve no purpose since the exhaust valve has a radius of 0.5 inches. With a cracking effort of less than 0.5 inWC, you will start getting a very minor free-flow when vertical, due to the water column differential pressure.


The last statement from @Nemrod in the quote below is very accurate. The adjustment possibility is a secondary benefit and very rarely needed.

And yes, the first stage orifice (volcano in shape also) is also replaceable, if it is ever damaged and the sealing edge is less than perfect. It uses the same replaceable orifice as most Aqua Lung modern diaphragm first stages.

"The useful advantage is that the orifice is now replaceable and a damaged orifice no longer ruins an expensive piece of equipment."

Never. Leave it aligned to the middle position and flush to surface. Turning the orifice out can result in insufficient gas flow as the orifice will retreat into the broach it sits inside and turning inward can alter/drop the lever adjustment.

Here is a photo of my DD6 Kraken now owned by a buddy. You can clearly see that if you turn that orifice out that the LP seat will come to rest upon the edge of the broach, not the knife edge, restricting air flow. That is not good.



Correctly aligned adjustable orifice and set flush for best engagement with the LP seat.



The useful advantage is that the orifice is now replaceable and a damaged orifice no longer ruins an expensive piece of equipment.

 

[Wallowa]

Fascinating.....thanks, very clear description of function and design.

Luis....is there a user's or repair manual?

Thanks...Phil
AK19-067

 

[Luis H]

Hi Phil,

Sorry, I have not had the chance to write any kind of a comprehensive manual.

For a repair manual of the first stage, it is OK to use the service manual for an Aqua Lung Conshelf or the older Titan. I intentionally used all the same internal valve components in the design so that parts will be available for a long time.

The second stage is a very simple downstream demand valve. The seat can be easily replace without affecting any adjustments. The second stage is locked with the two side screws, but once the side screws are removed, the lever can be lifted to retract the seat carrier and the second stage can be unscrewed as a complete unit. The seat can be replaced (or even flipped over) and the second stage can be reinstalled. Just need to make sure the lever is lifted during the process to avoid cutting the soft seat.

None of this should be done if you are not familiar with servicing a regulator. But if you are familiar with regulator service, this is all very simple and straight forward.

There are a few improvements and other minor details that I can expand on, but this should be good for now.

There is a regulator company that has approach me about restarting production of the Argonaut/ Kraken, but progress has been a bit slow. Maybe after they move forward, I will write a manual of some kind. For the most part I should be able to collect all the different stuff I have been writing in the last 15 years or so...

Good luck and have fun with it.

 

[Luis H]

I should have mentioned the following.

If anyone is going to turn the second stage volcano orifice (for whatever reason), the soft seat needs to be retracted from the orifice to avoid the volcano orifice edge cut into the soft seat. Therefore, the regulator must be open, and the second stage needs to be lifted or pushed down to lift the seat carrier.

If the orifice is going to be adjusted (for whatever reason), the lever height will also have to be adjusted, therefore the can needs to be open anyway. Moving the orifice in or out with affect the lever height.

For a full and complete overhaul (something very rarely needed), the second stage mechanism would be removed first as a complete subassembly, before removing the volcano orifice.

If you need full service, you may want to contact @rsingler here in SB.

Good luck and happy double hose diving.

 

[Nemrod]

One thing I did not mention and I do not think Luis touched on it, turning the orifice screw without pressing down on the diaphragm lever may result in cutting the LP soft seat. Another reason, if'n you need more reasons, to just let it be.

Oops, that is what I get for not refreshing the page. Oh well .