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Thread: pool orifice, 100%, Dolphin, What's your experiences?

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    Troy R. Legner tlegner is on a distinguished road tlegner is on a distinguished road tlegner's Avatar
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    pool orifice, 100%, Dolphin, What's your experiences?

    What are your experiences using the 100% pool orifice with the Dolphin?

    Mixes, cylinder percentages used, depths, deco, etc...

    What have you used this orifice for, or thought about using it for?

    How did you use it or what are your ideas for using it?

    What range of loop FO2% fluxuations did you have?

    Did you use a seperate bypass gas of a lower percent?

    See ya,
    Troy

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    Re: pool orifice, 100%, Dolphin, What's your experiences?

    I have read that some have used the 100% orifice with an Apex DS4 and achieved a flow of .9 L/min. This was done with a filter in-line to protect the orifice.
    Anyone else use the pool jet this way? I would like to know the fluxuations in loop percentage and any spikes that might occur?

    see ya,
    Troy L

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    Re: pool orifice, 100%, Dolphin, What's your experiences?

    Quote Originally Posted by tlegner  View Original Post
    I have read that some have used the 100% orifice with an Apex DS4 and achieved a flow of .9 L/min. This was done with a filter in-line to protect the orifice.
    Anyone else use the pool jet this way? I would like to know the fluxuations in loop percentage and any spikes that might occur?

    see ya,
    Troy L
    Hi Troy,

    It Primarily depends on what your personal metabolic rate is.

    If you only need .65lpm, and the orifice is flowing at .9lpm you now have excess oxygen that is not being used which will cause your PO2 to potentially reach unsafe levels.

    Cheers

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    Re: pool orifice, 100%, Dolphin, What's your experiences?

    Quote Originally Posted by JasonF  View Original Post
    Hi Troy,

    It Primarily depends on what your personal metabolic rate is.

    If you only need .65lpm, and the orifice is flowing at .9lpm you now have excess oxygen that is not being used which will cause your PO2 to potentially reach unsafe levels.

    Cheers
    My VO2 is 1.12 L/min, 1.01 at near complete rest.
    I am presently exploring the idea of using an original Drager first stage. The 242 psi will run thru a Swagelok dual needle valve. This should choke the flow to achieve an ideal back pressure to go into a 100% "pool jet" orifice.
    I see several advantages to this. I can vary the flow to the orifice to fine tune the dose. The use of a sonic orifice has its own advantages over just a needle alone. The needle valves would operate under consistent conditions. I believe this would very accurately simulate ideal back pressure and flow to the orifice. I would be running it thru the original dose unit. There are mixing questions I have about that.

    One idea is to use the manual O2 add valve to bypass the needle valve. This should put the full 242 psi into the 100% orifice to flow ~1.8. My thought is that with this slow flow the mixing will be more homogenious. The time it takes to make adjustments might be a little too long. It would make a nice fine adjustment method when needed but not sure about it for use as the standard/ only add valve.

    Any thoughts out there on this and flow rates thru the O2 add valve?

    I am sure some of you have done this or something like it before. I read one posting of this applied to a kiss valve. This is similar but under less initial IP. I am thinking that the drager first stage offers a better starting point to work from.
    Any thoughts you all may have would be appreciated.
    Thanks,
    Troy Legner

  5. #5
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    Re: pool orifice, 100%, Dolphin, What's your experiences?

    Quote Originally Posted by tlegner  View Original Post
    My VO2 is 1.12 L/min, 1.01 at near complete rest.
    I am presently exploring the idea of using an original Drager first stage. The 242 psi will run thru a Swagelok dual needle valve. This should choke the flow to achieve an ideal back pressure to go into a 100% "pool jet" orifice.
    I see several advantages to this. I can vary the flow to the orifice to fine tune the dose. The use of a sonic orifice has its own advantages over just a needle alone. The needle valves would operate under consistent conditions. I believe this would very accurately simulate ideal back pressure and flow to the orifice. I would be running it thru the original dose unit. There are mixing questions I have about that.

    One idea is to use the manual O2 add valve to bypass the needle valve. This should put the full 242 psi into the 100% orifice to flow ~1.8. My thought is that with this slow flow the mixing will be more homogenious. The time it takes to make adjustments might be a little too long. It would make a nice fine adjustment method when needed but not sure about it for use as the standard/ only add valve.

    Any thoughts out there on this and flow rates thru the O2 add valve?

    I am sure some of you have done this or something like it before. I read one posting of this applied to a kiss valve. This is similar but under less initial IP. I am thinking that the drager first stage offers a better starting point to work from.
    Any thoughts you all may have would be appreciated.
    Thanks,
    Troy Legner

    Troy,

    Try thinking thru this dual restriction idea again.

    I get the impression that you're seeing 2 orifices as a 2 stage pressure reducer, and while it may work that way along a specific pressure gradient / flow line, it won't work that way otherwise.

    If your needle valve opening is even slightly larger in effective cross sectional area than the orifice, then pressure will gradually build behind the orifice to full IP pressure, you'll have a sonic flow condition and the fixed orifice will control as if no needle valve was there.

    If the needle valve is set even slightly smaller than the orifice, then it becomes the controlling orifice, you'll not have a sonic flow condition at the fixed orifice, and the fixed orifice may as well be a barn door.

    Dual restrictions are usually set up with the fixed restriction first, which lets a larger variable restriction, which would otherwise have a huge range, to have a much tighter range of control.

    An example would be a partial pressure fill station where the O2 fill whip whip might have a fixed restriction right before a scuba valve where it connects to the tank.


    Darlene

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    Re: pool orifice, 100%, Dolphin, What's your experiences?

    Quote Originally Posted by Scuba_Vixen  View Original Post
    Troy,

    Try thinking thru this dual restriction idea again.

    I get the impression that you're seeing 2 orifices as a 2 stage pressure reducer, and while it may work that way along a specific pressure gradient / flow line, it won't work that way otherwise.

    If your needle valve opening is even slightly larger in effective cross sectional area than the orifice, then pressure will gradually build behind the orifice to full IP pressure, you'll have a sonic flow condition and the fixed orifice will control as if no needle valve was there.

    If the needle valve is set even slightly smaller than the orifice, then it becomes the controlling orifice, you'll not have a sonic flow condition at the fixed orifice, and the fixed orifice may as well be a barn door.

    Dual restrictions are usually set up with the fixed restriction first, which lets a larger variable restriction, which would otherwise have a huge range, to have a much tighter range of control.

    An example would be a partial pressure fill station where the O2 fill whip whip might have a fixed restriction right before a scuba valve where it connects to the tank.


    Darlene
    Darlene,
    I left out a few points in my posting. The needle valves are mostly in control like you said. I am thinking the orifice will take on other rolls in line with the needle valves.

    The pressure drop is only “simulated”. The actual pressure is still 242 psi just like you said.

    My thinking is that the orifice will serve to isolate the needle valve and keep it in a more constant condition. My needle valve will not be located where I can adjust it on the dive like most (at least not at this stage. I’m working on it). This is a lesser function along the way.

    A larger purpose is that this setup creates a way to tap into the pressure drop on across the needle valve for a mav. Most manual add valves operate under a lower IP than the 242 psi. The manual add valve is actually under 242 psi but the differential can be halved tapping in across this needle valve. The orifice offers restriction of flow ultimately to ~1.8 L/min. This relieves the stress on O ring blow out in the mav and caps the final ultimate flow.

    If the mav went directly from the 242 to the dose unit it would result in an injection quantity that might be more than desired. I would guess that less is better than more. I can always hold the button longer but can’t undo an overshot of o2 as easy. It is possible to split the flow from the mav across more dose jets like the 5.8 L/min for a total of 7.6 L/min thru the mav, with more hardware, higher than wanted mav flow, and more complexity.

    Hopefully others will chime in and offer their experiences and comments on this approach and flow rates thru their mav.

    I also think that the orifice will serve to obtain a finer tuning of the flow with the needle valve. The pressure will build up on the orifice but the flow will not be the same as it would with the needle valve alone.


    The actual higher IP will show its true potential as the orifice loses its differential needed to maintain a sonic flow the needle valve will keep pushing and nullifying the orifice as if it was not there. The needle is a choked flow but not a sonic flow. In the dual needle, the flow thru the second needle is, in my opinion, backwards. May or not have an effect. Not sure.
    All thought would be appreciated. Thanks,
    Troy Legner

  7. #7
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    Re: pool orifice, 100%, Dolphin, What's your experiences?

    Troy,

    Sketch out a plumbing diagram of how all these parts are going to be placed in the system.

    It sounds like you plan to have a MAV in parallel with a needle valve, both of which are on the supply side of a Drager 100% orifice.

    It also sounds like you're expecting the pressure difference between the 1st stage reg side of the needle valve and the orifice side of the needle valve to be in the range that common MAVs can work in. .....

    That's not likely to occur, at least predictably.

    If the needls valve is set to flow less than the orifice can, then the diffential pressure across it will increase as the flow rate of the needle adjustment becomes smaller with respect to the orifice's flow capability. Probably higher than most MAVs can handle.

    If the needle is set to flow more than the orifice, then there won't be any pressure drop accross the valve, and the mav can have no effect on the flow either.

    If I'm understanding your thought process, then what you're looking for is that small gray area where the needle valve is set to flow somewhat less than the orifice can, so that you could push the button for a burst of extra flow.

    If that's the case, and if this is intended for O2 control on an mCCR setup, then here's the issue:

    The Drager O2 orifice flows something like 2.5 l/m, more than twice your metabolic rate.

    You'd have to set the needle valve in the 1.0 l/m range (and that's if you have a plug in place of the orifice in the MAV) so that PO2 doesn't soar out of control.

    With that much differential in flow rates, the pressure across the needle valve (and with it, the MAV) will be very close to the 16 bar IP. ... There just is not going to be a pressure drop (at least a significant one) across the valve to tap into for a MAV.

    Having a neelde valve, and then not having it where you can reach it easily makes as much sense as taking a crap but leaving the TP in the other room.

    If I've misunderstood your plumbing plan, please sketch it out, maybe I'm on the wrong track.

    Darlene
    Last edited by Scuba_Vixen; 1st February 2010 at 18:04.

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    Troy R. Legner tlegner is on a distinguished road tlegner is on a distinguished road tlegner's Avatar
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    Re: pool orifice, 100%, Dolphin, What's your experiences?

    Quote Originally Posted by Scuba_Vixen  View Original Post
    Troy,

    Sketch out a plumbing diagram of how all these parts are going to be placed in the system.

    It sounds like you plan to have a MAV in parallel with a needle valve, both of which are on the supply side of a Drager 100% orifice.

    It also sounds like you're expecting the pressure difference between the 1st stage reg side of the needle valve and the orifice side of the needle valve to be in the range that common MAVs can work in. .....

    That's not likely to occur, at least predictably.

    If the needls valve is set to flow less than the orifice can, then the diffential pressure across it will increase as the flow rate of the needle adjustment becomes smaller with respect to the orifice's flow capability. Probably higher than most MAVs can handle.

    If the needle is set to flow more than the orifice, then there won't be any pressure drop accross the valve, and the mav can have no effect on the flow either.

    If I'm understanding your thought process, then what you're looking for is that small gray area where the needle valve is set to flow somewhat less than the orifice can, so that you could push the button for a burst of extra flow.

    If that's the case, and if this is intended for O2 control on an mCCR setup, then here's the issue:

    The Drager O2 orifice flows something like 2.5 l/m, more than twice your metabolic rate.

    You'd have to set the needle valve in the 1.0 l/m range (and that's if you have a plug in place of the orifice in the MAV) so that PO2 doesn't soar out of control.

    With that much differential in flow rates, the pressure across the needle valve (and with it, the MAV) will be very close to the 16 bar IP. ... There just is not going to be a pressure drop (at least a significant one) across the valve to tap into for a MAV.

    Having a neelde valve, and then not having it where you can reach it easily makes as much sense as taking a crap but leaving the TP in the other room.

    If I've misunderstood your plumbing plan, please sketch it out, maybe I'm on the wrong track.

    Darlene
    You are on the right track with me. You are just seeing the final result a little differently.

    Yes, The needle is in series with the orifice, and then the mav in parallel to the needle valve.

    hypothetically speaking:

    If you remove the needle valve then the orifice sees 242 psi and flows about 1.8 L/min.

    If you remove the needle and adjust the IP to ~120 psi the orifice will flow .9 L/min. Others here are diving the pool jet with an Apex first stage. These are the flows they are reporting. Maybe slightly less pressure than 120psi.

    if you install the needle valve and adjust the needles flow to .9 L/min the back pressure between the needle and orifice will rise to ~120 psi and the orifice will flow the same ~.9 L/min.

    If you increase the flow thru the needle the back pressure will increase and the flow through the orifice will increase porportionally the same as if you made an adjustment the the first stage.

    The needle valve must be in hand, during diving, if you are using a non compensated first stage, but not if you are using compensated stage. It does not just as if it were an orifice.

    It is possible to then to also use a pressure gauge in this section to measure the back pressure and know the flow rates.

    The needle is not a pressure reducer in itself. The 120 psi will begin to rise towards the full 242 psi when the sonic orifice does not have at least 2X pressure differential over the orifice. In this event the needles flow of .9 L/min will be maintained thru the orifice even though it is out of the orifice sonic range. It would diminish in a regular KISS aplication.

    The established flow of the needle will be consistent up to its limitations given the 242 psi actual ip.

    There are variations in the total outcome of a sonic orifice to that of a Choked flow. I just can't find that information right now. It maybe minor. If is is then any deviations will be countered by the orifice since the needle will not be effected by ambient pressure within its range.

    With the Add valve in parallel to the needle, it can bypass the choke and deliver the full 242 psi to the orifice. This maybe twice the metabolic rate but still not enough for a typical manual injection shot without holding the button for an extra long time then normal. Given the injection thru the original dose unit it will be better for mixing but not too fun to hold. More predictable accuracy in delivery with experience.

    Golem tells me that their add valves can handle 250 psi. It might not be needed to run the add valve in parallel. May just need to run it through an orifice of its own to counter the higher pressure.

    I need to have the Needle Rebreather divers post their use of the needle valves. They will have a lot better insight to the diving characteristics of a needle valve and if it is actually needed to be in hand or there as an added benefit of adjustment. (I'm still working on it)

    I hope this explains things better. I do better some days than others explaining myself.
    See ya,
    Troy Legner

  9. #9
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    Re: pool orifice, 100%, Dolphin, What's your experiences?

    Quote Originally Posted by tlegner  View Original Post
    You are on the right track with me. You are just seeing the final result a little differently.

    Yes, The needle is in series with the orifice, and then the mav in parallel to the needle valve.

    hypothetically speaking:

    If you remove the needle valve then the orifice sees 242 psi and flows about 1.8 L/min.

    If you remove the needle and adjust the IP to ~120 psi the orifice will flow .9 L/min. Others here are diving the pool jet with an Apex first stage. These are the flows they are reporting. Maybe slightly less pressure than 120psi.

    if you install the needle valve and adjust the needles flow to .9 L/min the back pressure between the needle and orifice will rise to ~120 psi and the orifice will flow the same ~.9 L/min.

    If you increase the flow thru the needle the back pressure will increase and the flow through the orifice will increase porportionally the same as if you made an adjustment the the first stage.

    The needle valve must be in hand, during diving, if you are using a non compensated first stage, but not if you are using compensated stage. It does not just as if it were an orifice.

    It is possible to then to also use a pressure gauge in this section to measure the back pressure and know the flow rates.

    The needle is not a pressure reducer in itself. The 120 psi will begin to rise towards the full 242 psi when the sonic orifice does not have at least 2X pressure differential over the orifice. In this event the needles flow of .9 L/min will be maintained thru the orifice even though it is out of the orifice sonic range. It would diminish in a regular KISS aplication.

    The established flow of the needle will be consistent up to its limitations given the 242 psi actual ip.

    There are variations in the total outcome of a sonic orifice to that of a Choked flow. I just can't find that information right now. It maybe minor. If is is then any deviations will be countered by the orifice since the needle will not be effected by ambient pressure within its range.

    With the Add valve in parallel to the needle, it can bypass the choke and deliver the full 242 psi to the orifice. This maybe twice the metabolic rate but still not enough for a typical manual injection shot without holding the button for an extra long time then normal. Given the injection thru the original dose unit it will be better for mixing but not too fun to hold. More predictable accuracy in delivery with experience.

    Golem tells me that their add valves can handle 250 psi. It might not be needed to run the add valve in parallel. May just need to run it through an orifice of its own to counter the higher pressure.

    I need to have the Needle Rebreather divers post their use of the needle valves. They will have a lot better insight to the diving characteristics of a needle valve and if it is actually needed to be in hand or there as an added benefit of adjustment. (I'm still working on it)

    I hope this explains things better. I do better some days than others explaining myself.
    See ya,
    Troy Legner

    I believe I see exactly where our thoughts diverge.

    My analysis is that if you have a needle valve in a 16 bar IP line cranked down to limit the flow rate to ~1 l/m, then the pressure in the downstream line will be much closer to whatever the loop pressure is than ~100 + psi. In other words, the Drager orifice might as well be a barn door, as it won't offer enough restriction to effect a sufficient pressure drop across it.

    Your take is that it won't work like that, and that there will be somewhere around 100 psi or more differential across the Drager orifice that would then allow ~140 at the MAV.

    Even if that were to be the case, there's still a huge problem, the Drager orifice would kill the effect of pushing the button on the MAV to get a quick burst of O2 into the loop. All you could do is fill the hose from the MAV to the orifice to full IP, and wait for it to seep thru the orifice. You'd be holding the MAV button for 10 seconds, maybe way more, to effect what would otherwise be a half second burst.

    If you put an orifice before a MAV to reduce pressure before it, then pressing the button will be useless as there won't be enough supply flow.

    Oh, wait, the orifice in the MAV is gonna flow almost 1 l/m, you're gonna have to plug it and just use the manual pushbutton add capability and actually control you're O2 delivery with just the needle valve.

    This is becoming a shit load of plumbing to get squat.

    If the GG valve is good for 250, then try it by itself, I don't think you're going to like the finger tip pressure to open a push valve against that high a pressure, but I'm kind of a wuss, and run it thru a 32% orifice or better yet, remove the orifice altogether and use a Tecme injection port in it's place P/N A0030.

    Outside the box can be good, but don't loose track of the stuff in the box that still needs to be considered.


    Darlene


    I guess you'll just have to build it and then we'll know for sure
    Last edited by Scuba_Vixen; 2nd February 2010 at 01:20.

  10. #10
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    Re: pool orifice, 100%, Dolphin, What's your experiences?

    Quote Originally Posted by Scuba_Vixen  View Original Post
    I believe I see exactly where our thoughts diverge.


    Your take is that it won't work like that, and that there will be somewhere around 100 psi or more differential across the Drager orifice that would then allow ~140 at the MAV.

    Even if that were to be the case, there's still a huge problem, the Drager orifice would kill the effect of pushing the button on the MAV to get a quick burst of O2 into the loop. All you could do is fill the hose from the MAV to the orifice to full IP, and wait for it to seep thru the orifice. You'd be holding the MAV button for 10 seconds, maybe way more, to effect what would otherwise be a half second burst.


    If the GG valve is good for 250, then try it by itself, I don't think you're going to like the finger tip pressure to open a push valve against that high a pressure, but I'm kind of a wuss.

    Outside the box can be good, but don't loose track of the stuff in the box that still needs to be considered.


    Darlene


    I guess you'll just have to build it and then we'll know for sure

    Yes, we are on the right track!! And you also see the problems too. In order to only allow the MAV to see 140 psi I have to run it through the orifice. Yeah, its not looking good for having to hold the button for 10 minutes. In my other posting someone told me that their flow through the mav is 16 l/min. and he holds it for 2 seconds. Realistically that makes my setup holding the valve for 9 seconds. Have to re think that.

    The orifice really serves to hold the back pressure to take the load off of the MAV "without orifice".

    I will be traveling in 2 weeks so I will work on a design in my spare time for my own manual add valves, orifice, and needle options. I'm currently experimenting with anodizing. The shop smells very pungent right now.
    See ya,
    Troy L.
    p.s.
    Already talking to Martin about a DS4 first stage.

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