How long should it take to fill a 50L tank from empty?

  1. Submariner1 Member

    Messages:
    100
    Location:
    Berkshire
    Just wondered how long it should take this compressor to fill to 145 psi from empty?
    Seems to work fine, but as its my first compressor no idea if its performing properly.

    I am going to empty it down completely tomorrow, to check their is no water in it. Hence interested how long it should take to reach 10 Bar.

    is there a formula to work out ?

    Manual says to empty it after every session, is that necessary or can one just let a fair bit out of the drain valve (hopefully to remove any condensed water ) or do you have to let out all the air to get the water out?

    spec is:-
    kW 2.2 , Hp 3
    L/min 355
    c.f.m 12.5
    Bar 10
    Psi 145
     
  2. RonA

    RonA specialist in repairing sealed for life equipment

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    Location:
    Stockton on Tees, UK
    Is the reservoir 12.5 cubic feet capacity?
    RonA
     
  3. 8ob

    8ob Forum Supporter

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    Location:
    moscow on thames
    My pea brain has got the tank capacity at 10 x atmospheric so 500ltrs divided by the 355ltrs a minute = 1.4 minutes less pumping losses. :dontknow:

    Bob
     
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  4. m_c Member

    Messages:
    586
    Location:
    East Lothian
    This. But if it's your typical combined motor/compressor assembly, pumping losses will likely be quite high.
     
  5. James1979 Forum Supporter

    Messages:
    1,612
    Location:
    Orkney
    There will be water in it. It’s a by product of compressing air I’m afraid. It’s due to heating it up then cooling again I believe. Not sure on the exact science but smaller compressors work harder and get hotter hence more water in my experience.

    Don’t know what you’re using it for but mine runs a plasma cutter and water is bad. I’ve got the usual traps etc but the best thing I got was a timed solenoid valve on the drain. Exhaust through the wall to outside and keeps the air a lot drier. I’ve set it to 10s every 15 mins which seems fine.

    oh and I drain it fully every time I turn it off and leave the cock open without fail.
     
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  6. skotl

    skotl Forum Supporter

    Messages:
    7,379
    Location:
    Edinburgh, UK
    That works for my equally pea sized brain, as my 90l tank takes around three minutes from memory

    Also, I open the drain valve and let it empty (and leave the valve open) whenever I'm finished using it
     
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  7. m_c Member

    Messages:
    586
    Location:
    East Lothian
    How much water ends up in the tank, is all down to how humid the atmosphere is. If you run a compressor in 0% humidity (Serbia or the Sahara at peak heat would do it), then you won't get water in the tank.

    How much stays in the tank, and how much goes out the airline, is all down to how warm the tank gets in use. Compressing air causes it to heat up, so the smaller the tank is in relation to the compressor, the less surface area there is to dissipate that heat, so less moisture condenses in the tank and instead goes out the airline connection. The cooler you can get air before it reaches the tank, the cooler the tank will remain, with more moisture being trapped in the tank.
     
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  8. James1979 Forum Supporter

    Messages:
    1,612
    Location:
    Orkney
    Cheers. I knew it was along those lines. It’s my nemesis as it’s death to plasma tips so I try everything to get rid of it. Being in Orkney the moisture content in the air is a lot on a good day. More on a day like today
     
  9. skotl

    skotl Forum Supporter

    Messages:
    7,379
    Location:
    Edinburgh, UK
    Do you have a dehumidifier? Mine stopped working in the garage for three days before I noticed, and I only realised when I saw the sheen of rust on the tools I'd left out.
    Keeping it running 24x7 makes a massive difference, in my experience.

    Edit: This is what I have, although I got mine for £80 as an as-new refurb off ebay. It has a drain hose outlet so is permanently peeing out a thin pipe through the wall

    Buy Challenge 10 Litre Dehumidifier | Dehumidifiers | Argos
     
  10. Submariner1 Member

    Messages:
    100
    Location:
    Berkshire
    not sure says 50 Litres
     
  11. Submariner1 Member

    Messages:
    100
    Location:
    Berkshire
     
  12. Submariner1 Member

    Messages:
    100
    Location:
    Berkshire
    I think its what I call a separate belt drive motor and pump B5474D88-14D1-4989-AC6E-16926F095D31.jpeg motor and pump
     
  13. Submariner1 Member

    Messages:
    100
    Location:
    Berkshire
    Thanks for the info.
    Looks like drain every time is the way to go.
    Thats a real pain as the drain valve is going to jet wet air and water at the floor.
    Not much room under the tank.
     
    James1979 likes this.
  14. awemawson Forum Supporter

    I refreshed the Silica Gel in my home made air drier yesterday - all my air supply runs through it and I have a type of gel that changes colour when exhausted (so do I !!!) 3 hours at 130 degrees in an electric fan oven and it's good for another 3 months or so. I made a second one to feed this already dried air to my CNC plasma table, and so far it's never had to be refreshed in over 3 years.

    Drier is described here:

    https://madmodder.net/index.php/topic,11936.0.html
     
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  15. Submariner1 Member

    Messages:
    100
    Location:
    Berkshire
    thanks
    I think I will have to work out some sort of remote drain cock, as getting under this is not easy.
    Plus with this sound deadening mat, there is maybe only 20 mm clearance to the mat.
     
  16. awemawson Forum Supporter

    I fitted my main compressor tank with a timed drain down system, rejecting float systems as I've had them fail. This one blows down for a few seconds every 45 minutes between 08:00 and 17:00. Repeat and duration are the longest that the device can be set to, so I run it through a time switch so it doesn't blow off in the night time.

    Described here :

    https://madmodder.net/index.php/topic,11941.0.html
     
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  17. James1979 Forum Supporter

    Messages:
    1,612
    Location:
    Orkney
    Sounds a bit like what I have although I don’t have a time switch. Blows off when it’s working, drained down when it’s not.

    As far as OP’s drain goes, it’ll be a standard bsp thread I’d think. Mines 3/8. You can come from that into an elbow then away. If you’re tight on space either get an elbow and go straight into tank or raise it a bit on two bits of channel or I section. Weld a frame up if it needs but just laying them on the floor should suffice

    I put a drain run in with copper water pipe so the timer exhausts to outside through the wall. Saves getting moisture in the workshop unnecessarily
     
  18. m_c Member

    Messages:
    586
    Location:
    East Lothian
    They're generally a bit more efficient than the combined units.

    Personally, I'd never fully drain a compressor every day. Just make sure you have some kind of system to drain the water regularly.
     
  19. barking mat

    barking mat Barking at Pigeons

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    4,649
    Location:
    Brittany, The Arz Valley.
    Is the problem getting it up to 10 bar? Not eight?

    Non return valve issue?
     
  20. Submariner1 Member

    Messages:
    100
    Location:
    Berkshire
    I did this last night and put a small towel under the drain. Ended up with a 2” circle of wet frozen towel. So not that much water.
    But I had opened the drain valve after the first use, for enough time to pressure drop from 10 bar to 8 Bar.

    Question re leaving the drain cock fully open (which I did) after the total drain down. Would you leave it open in an unheated garage (not sure if your are heated) ?
    Although I assume its unlikely damp air would get back up such a small drain tap?
    And the same question, if you were not going to use it for 3 months?
    Just wondered would it be better or worse to drain down and leave for a few days, to ensure all water leaked out and then shut the valve?
     
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