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A Basic Education on Compressors - How To?

Discussion in 'Compressors, Boosters & Blending Systems' started by lobbolt, May 17, 2012.

  1. lobbolt

    lobbolt Contributor

    # of Dives: 50 - 99
    Location: Taipei, Taiwan, Taiwan
    Hello Scubaboard,

    I am looking for the most basic education on compressors, all aspects of the operation, maintenance, usage... etc. But, I am not sure where to start, for a starting coverage of this aspect of SCUBA.


    Can you help me by pointing out a book, manual, or course, as to where to start?

    Thank you!
  2. supergaijin

    supergaijin Contributor

  3. kwindham

    kwindham Registered

    Here are some of the things I have learned so far about compressors that I hadn't considered before entering the hobby:

    - Swagelok connections have been known to fail if not installed correctly (follow the manufacturer's install procedure for tightening exactly)
    - A common grease gun or (more conveniently because getting grease out of your lines sucks) the small hand operated hydraulic power packs can generate up to 10k psi so you can do your own hydro tests at higher pressures to check for safe connections.
    - Because of the above problems, it is best to use threaded hp fittings wherever you may be operating valves or be present
    - The eaton / voss hydraulic fittings typically found on bauer compressors are much superior to swagelok fittings. Instead of simply swaging the line, these compression fittings use a "cut ring" ferrule which cuts into and positively retains the line.
    - Aluminum interfilters, filters, tanks, etc have a finite lifetime 15-20 years. Fatigue can turn these into ticking timebombs.
    - Excessive oil consumption in a compressor is caused by cylinder glazing (honing the cylinder magically fixes this).
    - Replacement piston rings are brittle as hell and require technique and patience to replace without breaking them.
    - Rings must be gapped precisely or they will break.
    - Every last part in a bauer compressor is metric. The pipe threads are British and importing metric tube from another country is probably cheaper even after the shipping than buying the overpriced metric tubing domestically.
    - 5/16" tube is a good substitute for 8mm tube (dimensions are almost identical)
    - Replacing simple things like an o-ring can sometimes be a headache because it may only be sold as part of a $100 kit.
    - Be prepared for the fact that almost nobody knows how to work on a hp compressor.
    - You can disassemble a $100 moisture filter and recharge the molecular sieve material easily by slowly increasing the heat on it in a toaster oven over a period of several hours (heat too quickly and the escaping steam can crack the beads) up to about 250F. Disassemble the cartridge by cutting the top inch off and discard. When placing back into your filter assembly, use the spring and an addt'l spacer to keep it together. After refilling the cartridge, if it has an integral moisture indicator, it will reverse its color after a few days of exposure to the recharged media.
    - Tube failures just make noise, but larger failures (filters, interfilters, etc) can cause property damage. Some commercial shops place their compressors behind concrete walls to avoid injury.
    - Always keep some pressure in empty cylinders to avoid possible moisture entry
    - Cascading is a cool way to fill a bottle without a booster pump. You can almost get full pressure.
    - The last compressor stage rattles unless it has back pressure.
    - Ultrasonic testing is supposed to be better than hydro testing for finding cracks
    - Don't screw your final stage filter caps on 100%. Back off a 1/4 turn because the pressure cycling can make them bind up
    - Compressor oil absorbs moisture. Moisture destroys compressors. Somebody claimed on the internet that they change their oil every 100 hrs and have achieved 20 yrs without an overhaul on their 4th stage. wow...

    Well, that's about all I can think of for now...
  4. detsgtdavis

    detsgtdavis Contributor

  5. lobbolt

    lobbolt Contributor

    # of Dives: 50 - 99
    Location: Taipei, Taiwan, Taiwan
    Thank you for the help!

    It's very much appreciated! :D
  6. NAM001

    NAM001 Contributor

    # of Dives: 500 - 999
    Location: the moon
  7. Blue Abyss

    Blue Abyss Instructor, Scuba

    # of Dives:
    Location: Seattle WA
    Check out the Oxygen Hackers Guide from Airspeedpress.com A good start to all things compressor and fill related stuff.
  8. Randy43068

    Randy43068 Guest

    # of Dives: 100 - 199
    Good stuff, thanks

    Sent from my ADR6300 using Tapatalk 2

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