Calor Lite - half full or not ?

Discussion in 'Tech/Mech General' started by iceclimber, Apr 10, 2016.

  1. iceclimber

    iceclimber Funster

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    A bit of a techy question ? The calor lite 6 kg gas bottle weighs 10.5 kg full & apparently 4.5 kg empty (never actually checked weight of an empty ?)

    Can it be reasonably assumed that a bottle that weighs in at around 7.5 - 8 kg is half full ? Or, is there some non-linear relationship ...... as i'm pretty sure that the closer a gas bottle get to empty the more useless it is at providing a good enough pressure to cook with etc.... ?
     
  2. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    Yes that would equate to an approximately half full (or half empty depending on your outlook on life) 6KG cylinder. Certainly in low temperatures the overall cylinder pressure can drop (I've seen as low as 35 psi in a near empty propane cylinder in January but over 100 psi in a full one in July) but as the regulator drops this to a working pressure of 30 millibar (about 0.5 psi) it should not affect the cylinder's ability to produce useful vapour until it really is almost completely empty.

    D.
     
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  3. iceclimber

    iceclimber Funster

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    Hi Dave, thanks. Here's a quick question for you as you are on-line.

    I'm now happy my EBL99 is charging OK on EHU, with 14.2v initially & then dropping to 13.8v as the float voltage. (all as per the manual)
    BUT ...... today after i'd been on EHU for 36 hrs, & the batteries were definitely fully charged. Yet, for the 3 hrs drive home the alternator was putting 14.4v to the batteries ..... Is this correct ? Does the alternator go straight to the batteries or via the EBL99 ?
    (I have a victron BMV 700 across the batteries)
     
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  4. jonandshell

    jonandshell Funster

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    No it's half empty!

    But then again, we missed out on pre-booked Funster tickets for Peterborough!:)
     
  5. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    The alternator charge goes via the EBL unit. Schaudt electrics are generally very reliable and I see no reason to worry about your setup.

    D.
     
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  6. colmorangie

    colmorangie Funster

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    Morning reading the above and seeing that the gas pressure post the regulator is only 0.5 psi (less than atmospheric) does this mean that post the regulator if you get a Leek air goes in the system rather than gas coming out????
    Sure this is not true but don't understand why not?
    Thanks
     
  7. mjltigger

    mjltigger Funster

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    I think you are right. Hence it being difficult to light things if your system isn't perfectly sealed
     
  8. scotjimland

    scotjimland Funster Life Member

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    The reason is that the 0.5psi pressure is Gauge Pressure .. NOT Absolute Pressure

    A gauge is often used to measure the pressure difference between a system and the surrounding atmosphere. This pressure is often called the gauge pressure

    The absolute pressure - pabs - is measured relative to the absolute zero pressure - the pressure that would occur at absolute vacuum. All calculations involving the gas law requires pressure (and temperature) to be in absolute units.


    [​IMG]



    http://www.engineeringtoolbox.com/pressure-d_587.html
     
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  9. colmorangie

    colmorangie Funster

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    Ok so pressures quoted and shown on gauges are using atmospheric as zero. That makes sense so 0.5 psi is sort of 15.2 psi assuming they have used 14.7 psi as atmospheric.
    I suppose otherwise when my van tyres were down to 10 psi they would self inflate to 14.7..........
    Wow I am of for a lay down
     
  10. Geordies

    Geordies Funster

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    I'd doubt you'd come across any application where ordinary folk are reading any pressure relative to absolute zero. It's almost exclusively used in science and industry. Your going to be reading gauge pressure which is pressure relative to atmospheric pressure.
     
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