Draeger Orifices?

[NotDeadYet]

Before I waste a load of wedge on a Dolphin bypass valve, can the actual orifice be removed from the screwie-in-holder-tube-thingie?

I have a new RB on it's way and my KISS valve from the old one is getting shifted to the new one. My plan... my old RB has a p-port in the base of the scrubber... if (and that's a big if) the orifice can be removed I could replace it with a 0.004" off the shelf jobbie. Hook my O2 up to it, diluent up to the bypass and I now have a combined O2 addition and ADV in one unit. Add a drysuit valve for manual O2 addition to the exhale bag. However, if the orifices can't be removed then the plan is dead in the water. And before any clever clogs suggests it , the 100% OEM orifice has too high a flow rate, I've already checked. I'm intending it as a back-up unit so need the ADV and it has to be clean and simply rigged.

Ta,

Stuart

[johnv]

Originally Posted by NotDeadYet

Before I waste a load of wedge on a Dolphin bypass valve, can the actual orifice be removed from the screwie-in-holder-tube-thingie?

Yep, the dolphin bypass valve makes a great ADV and manifold, you can unscrew the brass sonic orifice bit to leave 2 small holes which are big enough for 1L / minute and flushes. I did this on my Mk 1 and it works fine. The main problem is that all the screw fittings are non standard, you need to get the "complete" unit and then cut the end of the hozes you get, you can then add re-usable hoze fittings of the type required, eg 3/8 UNF for your diluent, or 1/4 bsp to convert to swagelok, connect to a KISS valve etc.

John

[narked at 90]

hello stuart, yes you just unscreew the orofices(there are two in each fitting)
so if you nobbled one of the two you get a lower flow rate!!
and as john said the fitting are non standard but you can either reuse the fittings off a dolphin or tec-blue make adaptors to fit to standard hoses
or you as i did and just made my own
king regards
john

[NotDeadYet]

Cheers, John.

What I want to do is remove the actual orifice itself from inside one of these dosage thingies and replace it with a smaller orifice so that I don't need the KISS valve at all, if you see what I mean. Basically make my own Draeger 0.8l/min jet so the O2 LP hose attaches straight to it. Can the actual jet assembly be taken apart?

[narked at 90]

i know you can take out the jets but i dont know if you could fit anouther in it's place as i have never seen jets from other companys they may have differant carriers
the dreager ones are just little brass screew in types
i cant remember what the flow is on the pool jet but could you remove one of the two jets or block it then lower your i.p to get your flow? as the dolphins i.p is 16.5 so the jets where picked to go with that and they then used two jets in the same doesage port, so blocking one will half the flow rate.
does that make any sense?

john routley

Originally Posted by NotDeadYet

Cheers, John.

What I want to do is remove the actual orifice itself from inside one of these dosage thingies and replace it with a smaller orifice so that I don't need the KISS valve at all, if you see what I mean. Basically make my own Draeger 0.8l/min jet so the O2 LP hose attaches straight to it. Can the actual jet assembly be taken apart?

[johnv]

Originally Posted by narked at 90

the dreager ones are just little brass screew in types
i cant remember what the flow is on the pool jet

I think all the flow rates on the draeger orifices are too high for O2 addition.
I have a couple of small .0035 orifices packaged in a plastic capsule that allows them to be inserted into LP hoze, but you don't get a manual add.

John

[divetheworld]

Originally Posted by narked at 90

i cant remember what the flow is on the pool jet but could you remove one of the two jets or block it then lower your i.p to get your flow? as the dolphins i.p is 16.5 so the jets where picked to go with that and they then used two jets in the same doesage port, so blocking one will half the flow rate.

Read the above again, I dont think you caught what John is saying.
The Dolphin dosage units have TWO jets inside each module. If you use the 100% pool jet and block one of them the flow rate might be what you are looking for.
The pool jet (100%) is 1.5 ltrs/min.
If you only use one port, then you should find a reduction in flow as John stated. According to the maths, this should be half but with a different IP, this may be different in real life. I have tried things according to the math and then found it different because of some weird shit that I hadnt thought of.
Sometimes it's "Jeez, that works better than it should!" and sometimes its "Bollox, why is'nt that working".

Technical breakdown drawings are here-> http://www.danshop.com/dolphindosier.html

[NotDeadYet]

Ahhh... I think I'd a totally different idea of how the dosage head works. My idea of it was that it had an input to the ADV which was either open or close plus another port for constant flow addition where you fitted the appropriate jet. Have I got it totally wrong? Are the orifices used in combo with one another, you don't pick the one you want, hook it up and forget the others?

What I was hoping I'd be able to do is take a jet, either remove the orifice or drill it out and fit an off the shelf orifice in it. I've got a few Norgren orifices would give the same flow rate as a KISS. But if the orifices are used in combination with one another then the idea is a no goer.

John, I wasn't bothered about the manual add, it's a sidemount RB and it has a drysuit inflator on the exhale lung where I can reach it.

Oh well, saved myself £200

Cheers,

Stuart

[johnv]

Originally Posted by NotDeadYet

Ahhh... I think I'd a totally different idea of how the dosage head works. My idea of it was that it had an input to the ADV which was either open or close plus another port for constant flow addition where you fitted the appropriate jet. Have I got it totally wrong? Are the orifices used in combo with one another, you don't pick the one you want, hook it up and forget the others?

stuart, you have exactly the right idea, the ADV input goes to an LP port on the 1st stage and the orifice goes, via a seperate LP hoze to another port on the 1st stage. You select the orifice by changing the port that the orifice host is screwed to. refering to the diagram on the above post, drager never really intend you to unscrew the brass orifice parts, you simply select the size orifice you want by screwing the LP hoze into the correct one and screwing blanking caps onto the others.

if you're near bristol, or are at the next section meeting, give me a nudge and I can show you what you need to see. Using the unit as an O2 manifold and and ADV works well. it's a right good ADV too.

John

John

[NotDeadYet]

It makes sense now, you select the orifice by moving the hose not the way I thought which was just installing a single orifice. Ta for that John. Tecme do adaptors to let you use standard reg hoses on the unit, so I may price it up.

Cheers,

Stuart