water flow project

Discussion in 'General Electronics Chat' started by SonOfAnarchy ZA, Jan 14, 2014.

  1. SonOfAnarchy ZA

    Thread Starter Member

    Jul 13, 2011
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    Hi guys I'm trying to do research on a project that im going to be starting soon. basically im going to use an Arduino to sense the flow of water. My question is what would the best sensor be to pickup the water flow through a clear tube. I don't need flow rate(would be nice but not necessary).:)
     
  2. inwo

    Well-Known Member

    Nov 7, 2013
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    External or can it be internal?

    I've researched and experimented with several types.
    I've only used internal devices, plumbed into the stream.

    There is the paddle type, water wheel, probe, and external reed switch with magnet inside.

    The paddle type adds quite a bit of restriction and fouls easily.

    The probe works electronically by sensing the difference of temp. between the in & out side of heated probe.
    Needs lots of recalibration with rust bacteria fouling.

    An ultrasonic sensor can work externally if you need to measure thru the tubing.

    The water wheel type works best for my application. I count the pulses with plc to display flow rate in GPM.
     
  3. SonOfAnarchy ZA

    Thread Starter Member

    Jul 13, 2011
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    thanks for the reply

    would this work http://www.communica.co.za/Catalog/Details/P0667377023. my worry with a paddle type sensor is it will be measuring the flow of water and methanol im worried the meth will damage the sensor. all i really need is to detect the presence of the water meth mix
     
  4. inwo

    Well-Known Member

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  5. sirch2

    Well-Known Member

    Jan 21, 2013
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    Google Electromagnetic flow meter. Basically the water acts as a conductor moving through a magnetic field and generates a current. You need a couple of coils on the outside of the pipe and a couple of electrodes through the pipe wall to pick up the induced current.
     
  6. SonOfAnarchy ZA

    Thread Starter Member

    Jul 13, 2011
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    that looks perfect! im just worried the methanol eats it away or makes it brittle
     
  7. SonOfAnarchy ZA

    Thread Starter Member

    Jul 13, 2011
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  8. wayneh

    Expert

    Sep 9, 2010
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    I think that would work fine as long as your stream is "clean" and free of debris. It has moving parts I think, so it could be prone to fouling. I'm also a little leary that the description doesn't mention a range of flow, the minimum rate need to trigger the switch, or anything like that. And no mention that the fluid-contact parts are all the same metallurgy.

    You said you have a clear tube? I'd consider a break-beam optical method. Totally no-contact.
     
  9. inwo

    Well-Known Member

    Nov 7, 2013
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    This isn't a complete answer but it mentions that it's nylon construction.

    "Hi, can i operate this water flow sensor under salt water?

    Yeah, it is made of nylon with fiber that can be used in the salt water."

    And this,
    "Many resins, nylons and rubbers, particularly nitrile (Buna-N), ethylene-propylene, teflon and neoprene are used satisfactorily as components of equipment in methanol service."

    The wheel type are great in that they out put an accurate flow rate.
    In my app. I needed a positive indication of flow. Other types could give false positive when fouled.


    As a wheel can't rotate without flow it's very fail-safe.
     
  10. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Many of the impeller type flow sensors you can buy are meant for fuel flow monitoring in automotive apps.

    Their datasheet should state what type of fuels they are safe with, and that probably includes ethanol and methanol.

    Just watch out for temperature, if your liquids are above room temperature.
     
  11. SonOfAnarchy ZA

    Thread Starter Member

    Jul 13, 2011
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    thank for the reply's appreciate it!
     
  12. SonOfAnarchy ZA

    Thread Starter Member

    Jul 13, 2011
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    ok after a bit of research i found that the flow sensor is not going to work as the flow rate is a maximum of 250psi and my system will run at 300psi. All i really need is to detect the presence of liquid in the system. any ideas?
     
  13. inwo

    Well-Known Member

    Nov 7, 2013
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    Need more information.

    What does pressure have to do with detecting flow?
    psi is not a flow rate?
    High pressure flow sensors should be available.

    There may be liquid in the line with no flow.

    A capacitive prox switch?
    Probes that sense conductivity of the liquid?

    Pressure sensor/switch in the part of the circuit where pressure changes with flow? Right after pump.
     
  14. wayneh

    Expert

    Sep 9, 2010
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    Methanol at 300psi? That's a non-trivial safety issue. I'm not sure anyone here should comment without a lot more detail about what you are doing.
     
  15. inwo

    Well-Known Member

    Nov 7, 2013
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    May not have to be concerned. "Methanol at 300psi?"
    Antifreeze maybe?

    Do need more information.
     
  16. SonOfAnarchy ZA

    Thread Starter Member

    Jul 13, 2011
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    ok so heres the full story:D

    I've got a water methanol kit for my car. I'm building a progressive controller. The kit has a 300psi pump and if the pump fails or i get a block in the piping or nozzle that would cause serious damage to my car so i would like to build a fail safe for the system. It will be a 50/50 water and methanol mix going through the line.
     
  17. wayneh

    Expert

    Sep 9, 2010
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    And so ends another thread.
    Take a look at the Terms of Service for this forum. Automotive modifications not allowed. (Unsafe things not allowed either.)
     
  18. SonOfAnarchy ZA

    Thread Starter Member

    Jul 13, 2011
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    that makes no sense what so ever this is my race car that is used in a safe controlled area(track) and all i want to do is to make the system safer???:confused:
     
  19. wayneh

    Expert

    Sep 9, 2010
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    Some of the rules around here are a bit squishy, as the mods try to retain some flexibility and allow a free exchange while still being safe. The automotive rule is not squishy at all. But I'm no mod, so maybe they see this case differently. Maybe a race car is not an "auto".

    I think I understand that you're trying to avoid a loss of flow of the water/methanol since it is providing cooling and slows detonation, similar to an octane boost.

    Were you thinking of protecting each cylinder individually? I'm trying to understand the flow rate. I think it's much lower than most industrial flow detectors will be made for. I was thinking detecting a loss of pressure would be easier, but that would not protect against a situation where it plugs, and you still have pressure but no flow.
     
  20. inwo

    Well-Known Member

    Nov 7, 2013
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