Gas Bottle volume indicator

Discussion in 'The Projects Forum' started by RodneyB, Nov 3, 2013.

  1. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
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    I would like to try and build an indicator that shows me how much gas I have left in my gas bottle.

    I have looked on the net for ideas but have found nothing suitable.

    I would imagine the best way is to measure the weight and then get it to light an LED to show you the volume.

    I have no idea how to go about this and would appreciate some advice. And direction

    Than you
     
  2. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
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    Are you serious or just playing around ???
     
  3. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
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    I am serious, I rely on gas for cooking, I purchase it in 20Kg bottles and often run out. I am seriously tired of this happening and I seriously want to build an indicator to let me know if nothing else when the volume is low.

    I am asking for ideas and guidance not a solution from there I will develop the project.

    Not sure why you would ask if I was serious. Or Joking, I don't ask on the forum unless I am really in need of assistance!
     
  4. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
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    I ask because some times people have to much time on their hands ....


    As far as a solution ...
    I am not sure but you could go 2 way that I know of .... One is to build a circuit with a pressure gauge to sound a alarm when the pressure falls below a certain point .. Or as you said get a scale and weight it and I can see that would be alot of problems to keep or maintain if the unit is outdoors or exposed to the weather..
     
    RodneyB likes this.
  5. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
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    Last edited: Nov 3, 2013
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Why not sit it on a scale and go by the weight as you suggested using a Load Cell.
    This is how most of the batch processing in the food industries and others is done.
    Omega can fix you up, I fitted one for a brewery for weighing Hops etc.
    Max.
     
    Last edited: Nov 3, 2013
  7. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
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    This is the kind of thing I was hoping for I will try and build a load cell. What is the measuring component in a load cell. I have to build it as I live in Zimbabwe and we don't have access to much technology.
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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  9. wayneh

    Expert

    Sep 9, 2010
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    My propane bottle has a gauge built into it and only cost a few bucks more than the ones without a gauge. Got it at Sam's IIRC. I believe it's a simple float gauge.

    We are talking about propane, right? FWIW, it's not a gas in the bottle - it's liquid. Quantitating a gas would require a pressure gauge or a weigh scale.
     
  10. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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  11. JohnInTX

    Moderator

    Jun 26, 2012
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    If you search Amazon for 'propane gas level indicator' you'll get dozens from simple liquid crystal tape (that senses the temperature difference between liquid and gas in the tank) to pressure gauges to fancy wireless transmitters.
     
  12. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    I just run my hand down the side of the tank while gas is being used. The cold level is the liquid level... Works for the little green camping bottles as well as the several gallon barbeque bottles..
     
  13. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    You could build a simple balance (a plank on a fulcrum) with a sliding counterweight to give you some indication of gas content.
     
  14. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    This is my kinda project.Often thought about this when we run out of gas sooner than it should have.

    I have a load cell around. This can be a project after I finish my current projects which is taking ages.
     
  15. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    My BBQ grill has a spring-loaded hook that holds the propane tank. When the tank is full the spring is stretched so the hook is about 4" below where it sits when empty. Think of a big "fishing spring-scale". It would be easy to add a microswitch near the "empty" height on setup like that.

    Ken
     
  16. tcmtech

    Well-Known Member

    Nov 4, 2013
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    One reasonably simple electronic solution would be to make a thermal comparator circuit that compares the ambient temperature to the temperature at the bottom of the tank.

    Reason being that when you are drawing vapor off your tank the liquid slowly cools down. When the volume of liquid becomes low the rate and extent of cooling will increase making the bottom the tank temp drop considerably more than what the ambient air temp is.

    At some point when the tank is low enough a comparator could easily sense the temperature differential having changed far enough and fast enough to give an fairly accurate indication that the overall fluid level is getting low.

    It may not be 100% accurate or reliable but under reasonable circumstances it would give you a way to be alerted to the tank running down. In theory anyway.

    More realistically a combination of weight and or tank pressure referencing system would be best.
     
    GopherT likes this.
  17. wayneh

    Expert

    Sep 9, 2010
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    FWIW, the pros use weight to fill the bottles and sell you propane by the pound.

    Reliability is going to be a problem if this is for an outdoor application. Moisture and dirt get everywhere and ruin everything. This argues for a simple non-electronic solution. Like a teeter-totter balance that raises the bottle when its weight falls below that of the opposing side.
     
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