How to use two air compressors to increase CFM

Discussion in 'Remodel Forum & Blog' started by cicerored, Nov 11, 2010.

  1. cicerored

    cicerored New Member

    Messages:
    27
    Location:
    Clay, New York, United States
    Hi,

    I have read that it is possible and safe to combine the output of two air compressors for high CFU applications. I was wondering how to accomplish this. It seems to me that using an unregulated air tank would be the best way. So the input of both compressors would be connected to the air tank and a 3/8" hose for the output.

    Anyone ever done this or have advise?

    Thanks
    Red
  2. Thatguy

    Thatguy Homeowner

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    Location:
    MD
    Last edited: Nov 11, 2010
  3. cicerored

    cicerored New Member

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    27
    Location:
    Clay, New York, United States
    The check valves are a great ideal. This set up would be parallel, right, with the two tanks into one?
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
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    Location:
    Cave Creek, Arizona
    quote; in series increases PSI.

    The ONLY way to increase PSI is to adjust the pressure switch. Put check valves on the outlet of the two compressors and use short hoses to connect them into a tee. It will also work without the check valves, because both have to be set to the same pressure.
  5. cicerored

    cicerored New Member

    Messages:
    27
    Location:
    Clay, New York, United States
    I just want to increase the CFU/Minute
  6. Thatguy

    Thatguy Homeowner

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    Location:
    MD
    Identical compressors, right?

    I don't see a difference between having two compressors running into one tank and your output is taken from that single tank
    or two compressors with both their tank outputs running into a tee.

    Just make sure there is no way to overpressure any tank.

    Can you post the specs of the compressors? It may make a difference with positive displacement compressors vs. others.
    Last edited: Nov 11, 2010
  7. leejosepho

    leejosepho DIY scratch-pad engineer

    Either way is fine since each motor must have its own pressure switch anyway ... and both motors even could be pushing air into just one tank with their respective pressure switches sitting side-by-side on a tee (or possibly even connected to just one switch if the switch can handle the load). Also, no check valves are needed (or even a good idea) anywhere other than between each motor and its tank. Using check valves in the outputs of two tanks teed together accomplishes nothing more than making it impossible for either motor to send air into the other tank.

    Edit for correction: A bleed valve and check valve likely *will* be needed for at least one tank in order to manually bleed that tank down to get that motor started at all ... and that means my thought of two pressure switches on a tee on one tank also needs some further thought!
    Last edited: Nov 12, 2010
  8. jimbo

    jimbo Plumber

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    8,997
    Location:
    San Diego
    Multi stage compressors are used for higher PSI. But as built, the guages and limit switches of "regular" compressors would not allow you to get higher PSI. I also doubt that the compressor itself would handle the much higher output, even though the DP is the same. Theory is correct,though. We used 4 stage compressors on the boats for the 4500 PSI air system.
  9. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    If both compressors are always under load you may not need a check valve. Things may get weird when the load is removed.
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,843
    Location:
    Cave Creek, Arizona
    Most compressors have an "unloader" on their switches so that the motor can start under load. The check valves would be so that the compressors could be disconnected without having turn off both compressors and drain the pressure from them.
    Last edited: Nov 13, 2010
  11. dlarrivee

    dlarrivee New Member

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    1,172
    Location:
    Canada
    He isn't looking for pressure, he is looking for volume.

    CFM is NOT PSI.

    HJ is correct, almost ALL newer compressors have an unloading valve so that the motor/compressor doesn't have to fight the compression of the full tank.
  12. raj

    raj New Member

    Messages:
    2
    Location:
    atlanta
    New compressor requirement

    Here is my brand new requirement…..

    “I’m looking for a compressor mechanism which should give me around 3500psi of air pressure.
    By using the natural air, at room temperature, is it possible to create the pressure of around 3500psi by using an air compressor. The compressors which are already available in the market are costing around $3000. It is too expensive for my usage and i cannot afford that much money.

    So that, I’m planning to build a new compression mechanism which suits my requirement.

    Can anybody help me how to generate this pressure or are there any other air compressors which are available in the current market for less than $2000.
  13. LLigetfa

    LLigetfa DIYer, not in the trades

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    4,066
    Location:
    NW Ontario, Canada
    In what way is this related to the 2 year old thread you dug up? I don't see anything within it that would apply.
  14. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,843
    Location:
    Cave Creek, Arizona
    You are trying to fill scuba air tanks, and NO standard compressor will come anywhere near that pressure. Most are limited to 150 pis MAX. Using them, the only thing you can increase is the volume. The pressure you want requiress specialized components and they would be highly regulated to make sure they are kept in a safe condition at all times. Otherwise, you would be working with a "bomb".
  15. raj

    raj New Member

    Messages:
    2
    Location:
    atlanta
    You are right HJ...i'm trying to fill Scuba air tanks...is there any way to make this new compression mechanism by my own....
    i heard that, bauer compressor, junior II gives the pressure of 3500PSI. but, this is too expensive. if possible, I'm planning to come up with a new solution for a less price. I just want to know the possibility, whether is it possible to manufacture or not and how difficult it is to manufacture a new compressor.
  16. nestork

    nestork Janitorial Technician

    Messages:
    98
    Location:
    Winnipeg
    You've kinda got the cart before the horse here.

    YOU need to think up a new way to inexpensively compress air to those kind of pressures first.

    THEN, based on your idea, you'll have some idea of whether it's possible to build a machine to do that.

    But, you're up against quite a challenge, cuz...

    Work = Force X Distance, or
    Work = (Force/Area) X (Distance X Area), or
    Work = Pressure X Volume

    You need to figure out a much less expensive way to do the same amount of work as the Bauer Junior II air compressor does.

    Good Luck
    Last edited: Sep 10, 2012
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