Normal intermediate pressure drop during purging?

[Bryan@Vintage Double Hose]

The cracking effort and flow rate of the Argonaut Kraken is on par with all modern regulators it was compared with and was actually better than most. It's not your Grandfather's double hose by any stretch.

 

[brtlmj]

OK, so the consensus seems to be that the drop I noticed is normal and nothing to worry about. Cool!

The regulator in question is an "old" Zeagle Flathead VI a.k.a. Apeks FST.

Thanks everyone!
Bart

 

[redacted]

IP drop does relate to breathing performance, but most modern systems are not effected in recreational diving conditions with reasonable supply pressures. Under more extreme conditions it may be more important This is one of the USN conclusions from their report (ADA048033) of the Scubapro Mk5 with Pilot 2nd.

"
Results of the test indicate that increased breathing resistance at
high RMV was due to first stage pressure drop instead of second stage
performance. Consequently, when the pilot second stage is supplied by two
first stages, inhalation resistance should remain nearly constant regardless
of the depth or RMV. However, the regulator has not been tested with two
ifirst stages nor will it be practical or necessary in most diving situations."

BTW, "high RMV" in this test was 75 l/m which is about 2.7 cf/min and testing was conducted to simulated depth of 300 ft.

That report also presents a few tables of data on IP drop as a function of supply pressure, depth, and air demand. It is interesting. (I have to wonder how much the filter comes into play for IP drop. When you look at results for different 1sts, any differences could be strongly influenced by the filter (and it condition).

Also, that reg was produced before most of us started diving.

 

[herman]

I don't find them to be even close. I think there's a reason they aren't mainstream anymore and marketing isn't one of them.

I would agree with you that unmodified DH regs of the past, esp with old parts were pretty poor performers compared to modern single hose regs but it's not true of updated ones. I have access to a modern computer based flow bench and recently had my Kraken double hose tested....in all fairness it's tweaked to the edge...but the results were impressive. It beat every single modern single hose reg in the computers data base including a Scubapro MK-25/A700 and an Atomic, don't recall which one, the only one that was better was a Posiden MK-3. The only time single hose regs got close or exceeded the Kraken (except for the Posiden) was on when the flow rates got above 11 CFM, which is a lot more than a diver can breath.
I have yet to test any of my updated DH reg but I suspect they will also come close since most of the updates are used in the Kraken....todays DH reg is not the same as the ones from the past.

 

[Boiler_81]

I would agree with you that unmodified DH regs of the past, esp with old parts were pretty poor performers compared to modern single hose regs but it's not true of updated ones. I have access to a modern computer based flow bench and recently had my Kraken double hose tested....in all fairness it's tweaked to the edge...but the results were impressive. It beat every single modern single hose reg in the computers data base including a Scubapro MK-25/A700 and an Atomic, don't recall which one, the only one that was better was a Posiden MK-3. The only time single hose regs got close or exceeded the Kraken (except for the Posiden) was on when the flow rates got above 11 CFM, which is a lot more than a diver can breath.
I have yet to test any of my updated DH reg but I suspect they will also come close since most of the updates are used in the Kraken....todays DH reg is not the same as the ones from the past.

I agree with the above, I have dove with the old style DH regulators, they for the most part breath hard. My rebuilt DA with a Phoenix nozzle and silicon diaphragm was an upgrade and closed the gap. My Kraken is a whole different ball game. I prefer it to my Apex single hose. The Kraken breaths well and has the added advantage of no bubbles in my face.

The Chairman should hook up with Bryan of vintage double hose and give a Kraken a try.

 

[tilikum]

I want a Kraken

 

[redacted]

Bryan

Without giving away too many secrets, what did you do to make the Kraken performance so much better than older DH regs?

 

[Bryan@Vintage Double Hose]

Bryan

Without giving away too many secrets, what did you do to make the Kraken performance so much better than older DH regs?

Since we just got a spot in the manufacturers section of the board I'll wait till they have Luis and Herman setup to moderate that section and then Luis can cover the topic in detail as he's the design engineer on it.

 

[Couv]

Since we just got a spot in the manufacturers section of the board.....

Congrats on getting a long overdue spot!

 

[buddhasummer]

I want a Kraken

Me too.