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Check valve for drops

  1. Jun 17, 2017 #1
    I'm having trouble finding any valves to use for my certain application. What I'm doing is trying to capture water droplets into a sealed container. What I need is some sort of check valve that needs nearly no pressure to let water through, but keep it contained once it has gone through the valve. Although I know this would be some sort of check valve, I have yet to find a type of check valve that will work. It will have to be oriented vertically, and must be automatic, meaning that I shouldn't have to open and close it manually or electronically. A swing, or tilting disk valve looks like it could work, but I'm not sure whether the disk would move when rotated around. Additionally, I've found ball drip valves, but haven't been able to really find out enough information to know whether or not it'll work. I know this isn't exactly a mathy or complex issue, but I figure somebody here must know what I'm talking about.
     
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  3. Jun 17, 2017 #2

    anorlunda

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    Might a cyclone moisture separator work for you?
     
  4. Jun 17, 2017 #3

    JBA

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    Will there be any back pressure on the check valve?
    does each drop have to immediately pass through the valve or can some water collect before the valve opens?
     
  5. Jun 17, 2017 #4
    It looks like cyclones are used to separate gasses or fluids at a more pressurized level, and they don't seem to have a check valve sort of end, so unless there is a certain type that does what I want, I couldn't find it.
     
  6. Jun 17, 2017 #5
    Some water can accumulate, but the less the better.
     
  7. Jun 17, 2017 #6

    anorlunda

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    That's right. To use one, you suck air from the container with a fan, force it through the cyclone separator, then blow the dried air back into the container. A separator has three connection, wet air in, dry air out, water out. Maybe that doesn't fit your app either.

    But water droplets don't easily migrate to a wall or a valve (think of a cloud in the sky, or fog). Even if you have a valve, how to you plan to get the drops to move to the valve?

    Another approach is that of a dehumidifier. Basically, it is a refrigerator that makes a plate cold. Water from the air condenses on the plate and runs down the plate to be collected in a bucket. A fan blows air over the cold plate.
     
  8. Jun 17, 2017 #7
    The dehumidifier approach is what I'm doing. Basically, I have a dehumidifier that will create the water drops, letting them roll off into a funnel, where they will have to go through the sort of valve that I'm looking for.This is just to keep the water in a contained space where it can't leak out, no matter its orientation. Imagine it like a water bottle without a lid, and only a check valve to get in.
     
  9. Jun 17, 2017 #8

    anorlunda

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    Ah ha. But if you need it to work in any orientation, a check valve won't work. How about a wick? A wick works, even against gravity.
    Aa
     
  10. Jun 17, 2017 #9
    I read a bit about wicking, and it sounds like the perfect method of doing this, but are there any pluming-esque devices that do this? Could I use a small tube and fill it with some material that would draw the water in one side and drip it out the other?
     
  11. Jun 17, 2017 #10

    anorlunda

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    I don't know of commercial devices. But your idea with the tube should work if you don't pack it too tightly.

    To improve the flow rate (if you need that) something to squeeze the outside end once in a while instread of waiting for a drip.

    Buy wick made for kerosene lanterns. Those wicks are very effective.
     
  12. Jun 17, 2017 #11
    It looks like these wicks are just cotton strips, so if I were to roll up a piece and put it in say, a rubber tube, would the liquid enter one side and flow through the entirety of the tube through to the other side and drip out there? And also, say i tipped the container upside down, could the water from the container come back through the wick in the wrong direction? If so, I'd imagine it would be plugged up and only release a bit of water at a time and not come rushing through.
     
  13. Jun 17, 2017 #12

    anorlunda

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    The purpose of a wick in a kerosene lantern is to lift fuel from the tank up to the flame, so yes it works uphill. Two inches vertical in my oil lamp.

    The coarseness of the weave in the material is critical, so some cloth is better than others.

    For more info, see this. https://en.m.wikipedia.org/wiki/Capillary_action

    You still have some engineering to do to make it practical. Size, shape, and so on.
    Good luck.
     
  14. Jun 21, 2017 #13

    JBA

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    There is a style of check valve that might work for you that is called a "duckbill check valve". Google under that title and you will find an array of manufacturers and designs of this type of valve. (Sorry for the delayed response but it took me forever to remember the correct name for this style.)
     
  15. Jun 21, 2017 #14

    anorlunda

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    The OP specified any orientation. I think he also means gravity feed. The duckbill (also called a joker valve) won't work in any orientation because the water won't run uphill.
     
  16. Jun 21, 2017 #15

    JBA

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    Post#1
    Post#7
    As stated, I believe the intent is to collect the water vertically as per Post#1 and retain it in any orientation as per Post#7.
     
  17. Jun 21, 2017 #16
    By retain, I just mean I don't want it to be able to flow back out if the container managed to get raised over level of the valve. I looked at duck valves, and though their principle seems perfect, it looks like it would take flow as opposed to drops or a stagnant weight of water to open it up. By chance, would you know if they have an extremely low opening pressure? At this point, a wick sounds like the right application.
     
  18. Jun 22, 2017 #17

    JBA

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    There would probably some water collection required but that would depend upon the thickness and stiffness of the duckbill end wall materials. These could be made very flexible and thin; but, at some point that might weaken the tip to the point that it would invert itself if the weight of the water is too high with the container upside down. Keep in mind that the duckbill valve is progressive opening, not snap acting, so that it is sort of a controlled leak device itself, so it only needs to flex enough at its center (it weakest opening point) to allow it to keep up with the drip rate.

    From a drip collection point, I agree that it would appear a wick is the best choice but, as stated above, if the container is tipped to the point that the bottom of the wick is submerged then then contained water can flow back up the wick and leak out. At the same time, the smaller the wick, the slower that leakage will be, so how much leakage will depend on the drip rate that the wick needs to absorb.

    Just a passing thought is that one possibility, if you have sufficient height available above the collection bottle, might be to use a combination of a wick with a duckbill valve below it that is able to open with a bit of collected water. That way,if the container is inverted, only the water between the wick and the duckbill would be leaked. Also if the container is to be removed and transported then only the duckbill need be retained with the bottle to prevent spillage.
     
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