NEEDLE VALVES

[rjack321]

You have to know the secret handshake to get one, though. I was told they were prototypes only available to testers and not for sale to consumers.

Maybe that's changed since I asked last year, though. I ended up getting a subgravity one and am quite happy with it.

Jim

It hasn't changed. They make all kinds of toys on the side for the special friends.

 

[tbone1004]

You have to know the secret handshake to get one, though. I was told they were prototypes only available to testers and not for sale to consumers.

Maybe that's changed since I asked last year, though. I ended up getting a subgravity one and am quite happy with it.

Jim

it has not changed to my knowledge.

 

[Heat Miser]

correct, no blocking necessary and the dual CMF's make it so you don't really have to touch it for depth changes, only workload changes.

None of the needles have to be blocked which is essentially the only reason they're really used on mCCR's, but you do have to adjust them as you change depths which is why guys like Fathom tell you to dive a blocked first stage anyway so you are only changing it with workload, but the Kiss design is a bit better

what are the pro's and con's of a dual CMF?

 

[rjack321]

what are the pro's and con's of a dual CMF?

con: there's 2x as much to clog up. @nadwidny knows the consequences of a clogged orifice
pro: you can dive with a dynamic 1st and not have to continually dick with the knob. you really only need to touch it for workload changes. So no depth limit

Alternatively, you can also just hike up your static IP to 200-225psi and not have mess with a regular needle valve with no CMF either. And if it clogs just open in up to pass the miniscule debris. Con, if you want to do 400ft+ dives you are still limited by the static IP.

 

[rddvet]

(not sure why I cant get that above quote to go away. Please ignore that part)

Out if curiosity, do you know if that tripple combination is designed so that the first stage doesn't require blocking but you get the adjustability?

Just a side note. My wife and I have done quite a few dives on unblocked 1st stages with the fathom needle valve. Sadly the reason is we've been plagued with the dreaded HP seat issues on Apeks regs that Apeks seem to deny exists. So we always had a backup unplugged reg ready to go. We've both done dives down to about 130ft with the unblocked regs. Neither of us were bothered by it, but I have to adjust alot more than she does. If I was doing much deeper dives I would definitely want a blocked 1st, but for shallower dives it's preferred, but not an absolute deal-breaker necessity.
As stated above, I've had tons of issues with Apeks regs and I can't stand them at this point. We've been slowly converting over to the Halcyon (same as a scubapro) diaphragm 1st. Martin at tecme can make plugs for that reg and they're cheap and he ships fast. I've been absolutely happy with the halcyons. The only issue is that for very deep dives that I don't do anyway (200ft plus), it's best to have a stronger spring. As far as I know, they're only available for Apeks regs.

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A ScubaBoard Staff Message...

The Apeks HP seat discussion is being split off to the new thread Apeks HP Seat failure: rumor or fact? in the Regulator forum.

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[Gone for diving]

As far as I know, they're only available for Apeks regs.

I have had custom springs made for other equipment, Not for a dive regulator...

So I am sure you can get some custom made, maybe 1 wire size up,... or a tad longer,
Just a thought...

 

[-JD-]

correct, no blocking necessary and the dual CMF's make it so you don't really have to touch it for depth changes, only workload changes.

None of the needles have to be blocked which is essentially the only reason they're really used on mCCR's, but you do have to adjust them as you change depths which is why guys like Fathom tell you to dive a blocked first stage anyway so you are only changing it with workload, but the Kiss design is a bit better

In theory you can use a dynamic 1st stage in any needle valve. In practice you will be f***ing with that tiny tiny knob constantly with even minor changes in depth (up down 20ft). It's a colossal pita with dry gloves on, or using a scooter, or with a camera.

Going from 0.2 LPM up to 1.2 LPM (who works harder than that diving?) is about 3/4 to 7/8ths of a turn. It's way easier to use a blocked 1st with a stronger spring so you can run a 200psi IP. That's a 400ft dive before you need to worry about your O2 shutting off.

Including a CMF in a needle valve negates one of the best features, the plain needle valves are clog proof.

(not sure why I cant get that above quote to go away. Please ignore that part)


Just a side note. My wife and I have done quite a few dives on unblocked 1st stages with the fathom needle valve. Sadly the reason is we've been plagued with the dreaded HP seat issues on Apeks regs that Apeks seem to deny exists. So we always had a backup unplugged reg ready to go. We've both done dives down to about 130ft with the unblocked regs. Neither of us were bothered by it, but I have to adjust alot more than she does. If I was doing much deeper dives I would definitely want a blocked 1st, but for shallower dives it's preferred, but not an absolute deal-breaker necessity.
As stated above, I've had tons of issues with Apeks regs and I can't stand them at this point. We've been slowly converting over to the Halcyon (same as a scubapro) diaphragm 1st. Martin at tecme can make plugs for that reg and they're cheap and he ships fast. I've been absolutely happy with the halcyons. The only issue is that for very deep dives that I don't do anyway (200ft plus), it's best to have a stronger spring. As far as I know, they're only available for Apeks regs.

Thank you all - Sorry, I should have been a bit more specific. I understand the blocking of the first stage with the needle valve is to eliminate the depth compensating variability in the IP and produce a static, but adjustable flow rate. I find the tradeoffs between the various rebreather design choices fascinating. Someday ...

@rjack I was thinking about what I had heard about clogging CMFs and was wondering at the tradeoffs vs. having to do a blocked 1st.

@rddvet I wonder if the Apeks compatible plugs and springs would cross over to the HOG D1/D2, DGX-D6, D6 - Excursion, DRIS Illusion (Dive Rite??) designs my understanding is that they are pretty similar conceptually. At < @200 ea. complete blocked spares would not be much of an issue vs Apek$$$$.

 

[jale]

Hi
I got Chris K valve and it seems to me that this one plus the Fathom plus the Subgravity are the same based on a iqsub mav block.
I use it with a "normal" reg and don't have any problem adjusting.
I found that with a zip-tie on the "stick", the adjustment is easier. After, it is like everything : just get used to
Too bad the KISS is not sold...

 

[jale]

Thank you all - Sorry, I should have been a bit more specific. I understand the blocking of the first stage with the needle valve is to eliminate the depth compensating variability in the IP and produce a static, but adjustable flow rate. I find the tradeoffs between the various rebreather design choices fascinating. Someday ...

@rjack I was thinking about what I had heard about clogging CMFs and was wondering at the tradeoffs vs. having to do a blocked 1st.

@rddvet I wonder if the Apeks compatible plugs and springs would cross over to the HOG D1/D2, DGX-D6, D6 - Excursion, DRIS Illusion (Dive Rite??) designs my understanding is that they are pretty similar conceptually. At < @200 ea. complete blocked spares would not be much of an issue vs Apek$$$$.

Hi
I don't know about the spring but I did used a HOG D1 5th port on a Apeks DST so the spring may be ok...just saying

 

[tbone1004]

The springs are compatible with Apeks-esque regulators.

Pros and cons were covered and I agree, especially with @rddvet 's point about the hassle of having a regulator kick it and not being able to/wanting to use a "normal" first stage. I use a Poseidon first stage because it has the only OPV that seems to not fail all the time but I have a custom brass plug made for it that Forrest Wilson had done some years ago with the Wet Mules. They used a bolt with a wing nut to set it, but the one I have is a brass plug that replaces the entire top assembly which does make it easier to adjust than the blocked ones, just have to be careful with them.