Aqualung Impulse 2nd stage metal tube?

[redacted]

I think the Impulse is a balance second stage it does not have the standard demand valve style but it does have the standard balance design. It's been awhile since I work on one of these and all the old catalog I have don't say one away or the other.

Little to hard to tell from that schematic but I think it looks like an unbalanced barrel poppet. Looks like the seat is simple hockey puck style and the spring looks like it rides high on the poppet. Plus no apparent groove for an o-ring on the poppet stem. If item 30 is a washer, then it is clearly unbalanced. If it is an o-ring, them it could be balanced but the proportions just don't look right. Needs a longer, skinnier stem on the poppet.

 

[Couv]

Agree, also there does not seem to be a balance chamber. But as Awap said, hard to tell from the picture. If it's balanced, then the knob may serve that purpose.

 

[Zung]

Here's an enlarged drawing with captions, and items 30 & 31 are o-rings, but I can't see how the "poppet" can seal with the knob. I'd call it unbalanced.

 

[herman]

I have an XR2 which is the same reg- it's my pool reg and I can assure you it's unbalanced. The design is very similar to the Scubapro 109. A plastic poppet held under spring pressure from the adjustment knob, there is no hole in the poppet or a balance chamber at the end.

 

[eelpout]

The Impulse 2nd stage is not balanced. The trick to tuning the Impule/ XR 2 is to set the adjustable orfice to the point where the it almost stops free flowing and then use the "adjustable spring tension knob " on the other side and shut the free flow with a 3/4 of a turn. You have to inform the user that when the reg start free flowing that you trun the knob to stop it. I have been working on these regs since they first started shipping them. They were one of the first Aqualung/ US Divers regs that had an adjustable orfice like the rest fo the reg in the market.

Jim

 

[redacted]

Clearly looks unbalanced. But then having 2 o-rings (30 & 31) looks like they have a seal above and below the threads on the adjuster. That should protect those threads but leaves an area where pressure stay at 1 atm. If one fails, it looks like the adjuster/case will still seal but that also leave the area where it can accumulate water but will not drain or clean without some disassembly.

Went back and looked again because I didn't see what limited adjuster travel. The pin (24) must engage the narrow part of the adjuster which leaves that area open to ambient pressure. So one o-ring must do the sealing job (31) and the other (30) must be there to center/stabilize the adjuster.

 

[Fishpie]

I think that the USD Gulf/ Kirby Morgan Superflow was the first USDivers adjustable 2nd stage.
A much better reg all around.

 

[NCadiver]

Aqualung just confirm that the Impulse regulator 2nd stage is a balance second stage.

 

[Couv]

Aqualung just confirm that the Impulse regulator 2nd stage is a balance second stage.

I would be interested in hearing how this second stage is balanced. From the diagram posted above, it certainly does not look balanced, at least not pneumatically balanced.

Could you give us a bit more detail please.

c

 

[redacted]

Aqualung just confirm that the Impulse regulator 2nd stage is a balance second stage.

When you look at the schematic posted by Zung, do you see a design that looks like it is pneumatically balanced? Remember, with the early Delta 2nds, Oceanic used to like to call them balanced and, if pressed, they would fall back on mechanically balanced.