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  1. #46
    Join Date
    Oct 2010
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    Perth
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    26

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    OP here...

    My current compressor is a Ryobi Airwave 50L direct drive but I also have a 2.5HP 80L V Twin belt drive unit that currently being restored and that will be the primary unit. Its a beast and I suspect is capable of producing 4 or 5 times the CFM of the Ryobi. My use of compressed air in the shop is very basic. Blowing down projects (both metalwork and woodwork), cleaning off degreaser from parts etc. Some die grinding using a very basic die grinder but only doing small projects. Some spray painting - mostly things like small boxes or bits and pieces for the car. Don't plan on doing whole cars! I've been making do for years with a cheap crummy Ozito oil less compressor so even the Ryobi is a big step up let alone the belt drive. I have ordered genuine Nitto HiCupler connectors in 1/2" thread and was planning on using 20mm hardline poly tube so that alone will be a massive improvement over the pissy little curly cord airline that came with the Ozito! I'll put a U shaped bend with a tap for collecting water just inside the shed and I will put a moisture filter in as well but hadn't planned to do much more than that. My air usage really isn't that critical...

  2. #47
    Join Date
    Feb 2006
    Location
    Perth
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    23,395

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    Well I finally got enough energy and the parts together to do the following.

    1) Retic'ed Lines.
    Converted all the remaining 1/4 and 3/8" reticulated line junctions, from the compressor, up to (but not including all) the outlets to 1/2" BSP. The main issue was at the compressor tank outlet which was using a 4 way 1/4" brass junction". At a couple of points in the system utilised short 1/4" flexible braided SS hose connections which have been replaced with 1/2" BSP pressure hose.

    2) Outlets.
    All 10 quick release outlets on the retic arms are have been checked for leaks/corrosion/damage.

    Previously the outlets consisted of an assortment of (Al, brass, steel) of 1/4” (size 20) and 3/8” (size 30) no name Nitto style fittings. The intention is to also eventually replace all the 20s with 30's, and some with 1/2” (size 40) steel genuine Nitto quick release fittings and so far I have replaced 4 of the 20s with 30s or 40's.

    Three of the 10 outlets are permanently connected to devices, ie plasma cutter, the cooling lube mister system for my metal mill, and the 20m hose reel located just above head height near the main door of the shed. These don't have high flow demands so can stay on 30's. 40's should work better with air tools.

    The leaks/corrosion/damage in the fittings probably arose from abuse (dropped on the floor etc) and excess water getting into the system and, for some of the non-ferrous fittings, from galvanic corrosion. The most corroded fittings were those made of Al, and the steel valve springs inside some of the brass fittings.

    3) Hoses.
    From 6 of the outlets there were 3/8" hoses of lengths, ranging from 2, to 20m (on a reel) in use at various points around the shed. A damaged 3/8" hose has been replaced with a new 1/2" hose and 1/2 fittings, and I have the makings of another shortish 1/2" one. These 1/2" hoses will be used on air tools.

    4) Water filter
    The "water in the lines issue" had been improved considerably a few years back when I installed an auto vent valve that opens the water drain under the tank for 1/2s every 45 minutes - I leave my compressor and auto vent valve on most of the time so there's far less water inside the tank. The effect of the vent valve is easily observable from the amount of water released from the reticulated system "low point" where a drain/tap can be opened to release water from that point. Depending on compressor use, prior to the installation of the auto vent valve the amount of water coming from the drain would be in the 100’s of mL range, whereas after the valve was installed it now <1/10th of that amount.

    However, when I run the compressor continuously for more than a few minutes (ie plasma cutter) the compressor tank does not get a chance to cool down and condense the water so the vent valve has a limited effect. I had a small inline water trap/filter at the end of one of the retic arms and could easily see water appearing in the sight glass. I thought about installing that small filter in the main trunk line but the small size (1/4") of the inlets and outlets of the filter almost certainly stymied the air flow so what I wanted was something larger.

    While i was thinking about this I stumbled on, literally at my feet, a box of assorted plumbing stuff I had scavenged from a skip at work including a standard Cuno SS water filter, and it dawned on me that a few $ worth of brass plumbing fittings would enabled me to install it into the compressed air trunk line at the point where the compressed air line comes into the shed as shown below. It had one pressure gauge point on the inlet side and I added the other to the outlet side - the pressure gauges are $8 ebay specials I had on hand for another (failed) project. When the filter is clean the pressure difference between the two gauges should be minimal and should only register a difference if filter was to start clogging up.
    With a clean water sediment filter installed the pressure difference is <1 psi.

    filterhousing.jpg

    Instead of hard plumbing the filter/water trap inline I used 1/2” hose and 1/2” BSP (40s) Nitto fittings so it can be easily removed if needed. The quick release fittings are not cheap but I figured if it completely fails I can use all the fittings elsewhere in my comp air system. You can see how much chunkier the clear 1/2" hoses are compared to the blue 3/8" in hose behind it. Using quick release fittings enable the two 1/2" hoses to be quickly removed from the filter and joined together while the filter is being serviced/fiddled with.

    The yellow handled tap in the photo is also a recent addition. This isolates the still full compressor tank outside the shed from the retic system inside the shed so I can work on anything down stream of the tap. Previously I had to go outside the shed, open the compressor enclosure and close a valve at the compressor tank outlet. Then repeat the opposite when I had finished so found myself constantly walking back and forth more than I wished,

    As far as using the Cuno as an actual air filter, I decided I would start with a standard 0.5micron water sediment filter which I already have a stash of for use on my under sink water filtration system for my coffee machine. I don’t expect this to catch much water as it is designed to let water but it filters down to 0.5 microns so should prevent fine particles getting through and I thought it would do as a starting point.

    Then I realised I would like to know how efficient any filter/trap/media is at removing the water vapour, so now I am up to my armpits investigating humidity measurements inside compressed air lines. So far I have knocked up a basic Arduino twin sensor humidity meter that compares compressor air intake air humidity with what's in the compressed air line, or can be used to compare pre and post filter humidity levels. However, it turns out to be a little more complex than I first thought as the humidity and humidity sensor is dramatically affected by the pressure. As some of you will know I don't mind mucking around with this stuff so I will be spending some time on this in the coming weeks. It's already making a good "inside the AC house" project when it's just too darn hot outside. When I have something that makes sense I will start a new thread about this maybe in the electronic forum.

    I have also recently found a source of desiccant pellets and will try this out when I get hold of the stuff. Apparently desiccant can generate even drier air than refrigerated air cooling. The benefit of using refrigerated air is the effectively zero servicing required whereas desiccant periodically requires replacement and/or regeneration by heating it in an oven for half an hour or so. This is OK if the regeneration is not needed too often but otherwise refrigerated air more readily suits high air volume users.

  3. #48
    Join Date
    Aug 2007
    Location
    Saskatoon, SK, Canada.
    Posts
    1,071

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    Bob 35 or 40 years ago I worked on air tankers used for dropping fire retardant on forest fires. They used a high pressure air system to open and close the bomb tank doors. We had to drain the systems daily or when the aircraft shut down for fuel and servicing. There were dryer bottles about the size of your filter and they were filled with marbles to increase the surface area inside the dryer chamber for the water to condense on. Since you like to experiment you could fill the bottle with glass marbles or the glass beads decorators love and see how effective they are at removing the water. They won't filter the particles but I remember them being quite good at removing the water and oil from the compressors.

  4. #49
    Join Date
    Feb 2006
    Location
    Perth
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    23,395

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    Quote Originally Posted by QC Inspector View Post
    Bob 35 or 40 years ago I worked on air tankers used for dropping fire retardant on forest fires. They used a high pressure air system to open and close the bomb tank doors. We had to drain the systems daily or when the aircraft shut down for fuel and servicing. There were dryer bottles about the size of your filter and they were filled with marbles to increase the surface area inside the dryer chamber for the water to condense on. S.
    Thanks for that. Sitting right in front of me is a vase with a bunch of these marbles in it!

  5. #50
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    Feb 2006
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    Perth
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    I have continued working on the Arduino absolute humidity meter and have posted about this in the Metal workers forum Humidity measurements in compressed air

    WARNING - the link is to an extremely science nerdy post - only go there if this topic really interests you as I don't want to be blamed for wasting your valuable shed time.

    The humidity meter has already been useful to, amongst other things, demonstrating that the location of my compressor affects the starting moisture content of the air. My situation applies in particular to compressor users who have their compressors located outside their shed in an enclosure. My enclosure uses a small vent fan in the false ceiling of the enclosure to vent/remove warm air from the enclosure while the compressor is running. Replacement air is drawn by the fan into the enclosure via a gap under the enclosure doors as I assumed this air would be cooler than air from higher up above the ground. However while it is cooler it is also moister, not helped by the fact that the floor of the compressor enclosure is teh top of a limestone retaining wall and several times a week the wall cops the garden sprinklers just 400 mm away. Some preliminary absolute moisture content measurements show that that the air just above the limestone floor is 20% moister than air 1.5m above the ground so just by changing the position of the air intake to the enclosure I might be able to change the moisture content of the compressed air in myself shed.

    Some caveats, this morning was quite still but the sprinklers have not been on for the last two days. It will be interesting to see what happens at other times like, just after the sprinklers have been on, or when it rains in winter, or when the stiff bone dry easterlies are blowing for a good 8 hours or so.

    If the moisture levels are consistently higher at the current draw location I will consider sealing the gap under the enclosure door and using a 100mm PVC pipe snorkel to draw air from above the line of the shed roof.

  6. #51
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    Feb 2006
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    Perth
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    Quote Originally Posted by BobL View Post
    If the moisture levels are consistently higher at the current draw location I will consider sealing the gap under the enclosure door and using a 100mm PVC pipe snorkel to draw air from above the line of the shed roof.
    Yesterday I measured the air moisture levels inside the enclosure a few mm above the air intake gap close to the limestone floor of the enclosure. Apart from down near the near by dampish garden bed, the moisture levels were was always higher inside than outside the enclosure, It was like, there was water coming out of the enclosure floor even though it looked and felt dry. After thinking about it for a few seconds it then dawned on me that this is where the compressor tank auto vent valve has been venting its condensed water load for the last 8 years!


    I'm guessing the vented water is being absorbed into the limestone floor and then the water evaporates back out of the floor into the enclosure air around the compressor. Additional water from rain or retic could also have been absorbed into the wall and travel up the wall and evaporate out of the top of the wall (ie enclosure floor) especially around the gap under the door which is where the air for the compressor and compressor cooling air is sucked into the enclosure.

    So I am going to
    a) Waterproof/Seal the floor of the enclosure
    b) Seal up the gaps under the door.
    c) fit an extension to the auto vent valve so that the vented water is ejected outside the enclosure!
    d) Add a snorkel to the enclosure so that (drier) intake air is drawn from higher above the enclosure.

  7. #52
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    Feb 2006
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    Perth
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    Quote Originally Posted by BobL View Post
    So I am going to
    a) Waterproof/Seal the floor of the enclosure
    b) Seal up the gaps under the door.
    c) fit an extension to the auto vent valve so that the vented water is ejected outside the enclosure!
    d) Add a snorkel to the enclosure so that (drier) intake air is drawn from higher above the enclosure.
    I've completed 3 of these 4 things.
    For pics and details see Humidity measurements in compressed air

  8. #53
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    Feb 2006
    Location
    Perth
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    Just picked up 2.5kg of free Silica gel crystals from a mate.
    Sigel.jpg
    They're a mix of orange and dark red. The orange are indicator crystals and turn green when saturated. Guess what's going into the filter

  9. #54
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    Feb 2006
    Location
    Perth
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    Just tried the desiccant out in the water filter holder and its works really well.

    To prevent crap and desiccant dust from escaping into the rest of the system I packed the desiccant around a standard 0.5 micron water sediment filter (orange arrow).
    The air comes in above the desiccant beads and then goes trough the beads, through the sediment filter and up though the middle of the filter to the filter outlet.

    To force the air to travel further through more desiccant I wrapped the outside top half of the sediment filter in cling wrap - this makes a major difference in the outcome.

    600gSIgel3.jpg

    The Absolute humidity in the using this setup reduced the moisture content of the compressed air by >97%.
    It's almost certainly less than this but am limited by the fact that a $5 DIY Arduino humidity sensor will not read below 1% relative humidity or 0.2mg/L. absolute humidity

    Even better, when I released a high volume of air from an air hose over period of 60s the absolute humidity at the outlet does not increase.
    I will try some even longer releases to see if the desiccant becomes overwhelmed.

    Here is what the whole shebang looks like.
    The business end is just the water filter cartridge - the rest is plumbing for the sensor .
    IOsystem.jpg

    Heres the display side of the absolute humidity meter.
    There are two sensors connected to this display unit.
    I = the sensor inside the compressed air line,
    0 = sensor outside the shed in the compressor enclosure.
    S = Saturated water pressure, and H = Absolute humidity.
    The readout shows H air in the line is 0.2 down from 7 mg/L or ~97%
    DIsplay2.jpg

    I wouldn't suggest going and buying a water filter holder specifically to do this but if you happen to have one laying around (a plastic one should work almost as well) then for the price of few plumbing parts and some Silica gel beads you can have very dry compressed air.

    The sensor and sensor plumbing was essential for me to accurately assess the setup and will be handy the future to know when to renew the Silica gel beads but as Bohdan mentioned you could use a transparent filter holder or put a small transparent chamber in the air line with a few indicator beads in it to tell you when the silica gel beads need attention.

  10. #55
    Join Date
    Feb 2016
    Location
    Canberra
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    2,829

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    BobL - going out on a limb here.

    I was talking with a spray painting mate and he recommended the use of Steel Camel filters for the lines with spray guns. Maintenance, Repair and Overhaul Products for Corrosion Control of Heavy Equipment and Cranes

    Steel Camel is specifically designs to utterly dry moisture from compressed air.

    NOW I was thinking about this post of yours! Given water pressure can be 500psi up to 1000psi - could I not get a clear water filter housing, add in a 0.5 micron filter and some visual indicative desiccant around it as you have? i.e. get a Really Big One like this? (20").... or put three in line.

    I've seen a few in an online search that are 18" x 6".

    I'm spraying, so I don't need 100psi... I strangle it to 15psi at the guns anyway.... so if I get 80 - or whatever - out the end of it I'd be pretty happy.

    One could easily just use plumbing fittings to attach it to the air lines.


    The clear tube will allow one to easily see when it's time for the oven!

    Thoughts?


    s-l1600.jpg

    e.g. https://www.clarencewaterfilters.com...lter-housings/

  11. #56
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    Feb 2006
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    Perth
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    Quote Originally Posted by woodPixel View Post
    BobL - going out on a limb here.

    I was talking with a spray painting mate and he recommended the use of Steel Camel filters for the lines with spray guns. Maintenance, Repair and Overhaul Products for Corrosion Control of Heavy Equipment and Cranes

    Steel Camel is specifically designs to utterly dry moisture from compressed air.

    NOW I was thinking about this post of yours! Given water pressure can be 500psi up to 1000psi - could I not get a clear water filter housing, add in a 0.5 micron filter and some visual indicative desiccant around it as you have? i.e. get a Really Big One like this? (20").... or put three in line.
    Mains water pressure is typically about 7 bar (105 psi) Here in Perth it is maintained between about 25 and 140 psi. Most mains water plumbing products are rated at 1 Mbar or more so you should still be OK.

    Anyway it should work.
    I would get one and try it out and see how long

    Given all the effort I put into mine with prefilter water condensation coils and auto water venting set I am a somewhat disappointed with how short a time the desiccant lasts. Some of this is due to some leaks in my system that I have not been able to identify although I have not had a really good look. This means the compressor runs far more than it needs to so it puts a fair bit of water through the system.

  12. #57
    Join Date
    Jun 2005
    Location
    Helensburgh
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    6,076

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    Quote Originally Posted by woodPixel View Post
    BobL - going out on a limb here.

    I was talking with a spray painting mate and he recommended the use of Steel Camel filters for the lines with spray guns. Maintenance, Repair and Overhaul Products for Corrosion Control of Heavy Equipment and Cranes

    Steel Camel is specifically designs to utterly dry moisture from compressed air.

    NOW I was thinking about this post of yours! Given water pressure can be 500psi up to 1000psi - could I not get a clear water filter housing, add in a 0.5 micron filter and some visual indicative desiccant around it as you have? i.e. get a Really Big One like this? (20").... or put three in line.

    I've seen a few in an online search that are 18" x 6".

    I'm spraying, so I don't need 100psi... I strangle it to 15psi at the guns anyway.... so if I get 80 - or whatever - out the end of it I'd be pretty happy.

    One could easily just use plumbing fittings to attach it to the air lines.


    The clear tube will allow one to easily see when it's time for the oven!

    Thoughts?


    s-l1600.jpg

    e.g. https://www.clarencewaterfilters.com...lter-housings/
    I use plain jane garden hose to connect my air reels to the copper feed and it runs at about 110psi. If I was to use a filter such as that I would be putting a guard around it in case the filter housing was damaged as plastic shards mightn't go far but they could hit someone.
    CHRIS

  13. #58
    Join Date
    Jul 2011
    Location
    Berowra Waters
    Posts
    154

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    Where do I find one of these “auto tank drains”?

  14. #59
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    Feb 2006
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    Perth
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    Quote Originally Posted by riverbuilder View Post
    Where do I find one of these “auto tank drains”?
    ebay
    Automatic Electronic Timed Air Compressor Condensate Auto Drain Valve 220V 1/2" | eBay

    ~$35 from Oz suppliers or $23 ($21 + GST) from China.

  15. #60
    Join Date
    Jul 2011
    Location
    Berowra Waters
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    154

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    Thankyou Bob 👍

    ~$35 from Oz suppliers or $23 ($21 + GST) from China.[/QUOTE]

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