View Poll Results: Do you use an air dryer with your wide belt sander?

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Thread: Air Dryer with a Wide Belt?

  1. #1

    Air Dryer with a Wide Belt?

    Curious how many people with wide belt sanders are using air dryers with them.

  2. #2
    Mandatory. Actually, any industrial machinery in the South.

    Erik
    Ex-SCM and Felder rep

  3. #3
    Quote Originally Posted by Erik Loza View Post
    Mandatory. Actually, any industrial machinery in the South.

    Erik
    I assume this is due to high humidity. So if you have a humidity controlled space, say 55% RH, do you still need one?

  4. #4
    Quote Originally Posted by derek labian View Post
    I assume this is due to high humidity. So if you have a humidity controlled space, say 55% RH, do you still need one?
    Yeah, still would. Widebelts usually have an onboard moisture/debris separator bit it’s pretty small and more of a failsafe. To put it into perspective, our techs require an external drier for any edgebander, widebelt, etc.

    Erik
    Ex-SCM and Felder rep

  5. #5
    Quote Originally Posted by Erik Loza View Post
    ... any industrial machinery ...
    Quote Originally Posted by derek labian View Post
    I assume this is due to high humidity. So if you have a humidity controlled space, say 55% RH, do you still need one?
    Quote Originally Posted by Erik Loza View Post
    Yeah, still would. Widebelts usually have an onboard moisture/debris separator bit it’s pretty small and more of a failsafe. ...
    This comes up repeatedly; sorry if it's repetitious to some.

    I'd suggest a air drier is required on any industrial machine using compressed air in a commercial operation (and 50% of the hobbyist uses as well) - anywhere/anytime the humidity exceeds maybe 10%. (the compressor, receiver size vs air usage volume/rate, air pressure drop, and temperatures all impact this %RH, but as general rule ... 10%). And the South has no monopoly on 'sticky'.

    Without beating the physics & thermodynamics to death, warm, high pressure air can hold a lot of water vapor. When you allow that air to expand, it cools, drops below the dew point, and it 'rains' inside whatever contains it. A pressure regulator, elbow, change in pipe diameter, or passing thru a control valve on a sander all create pressure drops (expansion). A filter/regulator/lubricator (FRL), or FR (no oil) at point of use helps. Drying the air at it's source is better. Membrane driers seem pricey, but are virtually maintenance free, and cheap relative to downtime and repairs.

    Compressing air increases the dewpoint. I've never analyzed it, but very much have to deal with the consequences and have always assumed this is why dryers are on the discharge of a compressor, not the inlet - - the increase in discharge dewpoint makes it easier to get the air temp below this, and so relatively dry.

    It's never enough to simply look at conditions in the shop. You have to consider what is happening inside the 'pipe'.

    In my business, it is a standing joke that occasionally we get air in our (compressed) 'Instrument Water'. And water is death to any number of automation devices, solenoid valves in particular.

  6. #6
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    Actually you can think about it fairly simply
    The amount of water in air is limited by the vapor pressure of water, which just depends on temperature
    Relative humidity is just the ratio of the partial pressure of water vapor to the vapor pressure at that temperature
    When RH% is 100% that is the maximum amount of water the air can hold at that temperature, anything above that will condense.
    So if you are at 55% RH and double the pressure it will increase the partial pressure to 110% of the vapor pressure. That 10% “over” will condense to bring it back down to 100%. So if your compressor increases the pressure by 8x to 105 psig
    It would mean that that the 10 torr partial pressure that ~50% RH at room temperature is would become 80 torr, but the air can only hold 20 torr at that temperature. So the 60 torr difference would condense. Ballparking (without a piece of paper )that would be about 1.5 mL of liquid water for every 5 gallons of tank size. And the air would be saturated with water vapor.

    John
    (Caveat All rough calcs in my head but the gist should be in the right direction)

  7. #7
    Quote Originally Posted by John Stankus View Post
    Actually you can think about it fairly simply
    The amount of water in air is limited by the vapor pressure of water, which just depends on temperature
    Relative humidity is just the ratio of the partial pressure of water vapor to the vapor pressure at that temperature
    When RH% is 100% that is the maximum amount of water the air can hold at that temperature, anything above that will condense.
    So if you are at 55% RH and double the pressure it will increase the partial pressure to 110% of the vapor pressure. That 10% “over” will condense to bring it back down to 100%. So if your compressor increases the pressure by 8x to 105 psig
    It would mean that that the 10 torr partial pressure that ~50% RH at room temperature is would become 80 torr, but the air can only hold 20 torr at that temperature. So the 60 torr difference would condense. Ballparking (without a piece of paper )that would be about 1.5 mL of liquid water for every 5 gallons of tank size. And the air would be saturated with water vapor.

    John
    (Caveat All rough calcs in my head but the gist should be in the right direction)
    I guess this is why you have to drain tanks after each use (or so manual says).

  8. #8
    A wide belt sander can last a long time if it is used by one competent and reliable operator. In shops where all use it they are abused and
    cost a fortune to repair.

  9. #9
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    Most of my air requirements in the shop are solenoids, valves, and clamps. So, mainly sensitive items.

    I run a Jun-Air compressor with a built in cooler and drier, along with that I have water separators at every machine. In addition, at some machines I run a lubricator to keep the moving parts happy.
    Bumbling forward into the unknown.

  10. #10
    Quote Originally Posted by Brian Holcombe View Post
    Most of my air requirements in the shop are solenoids, valves, and clamps. So, mainly sensitive items.

    I run a Jun-Air compressor with a built in cooler and drier, along with that I have water separators at every machine. In addition, at some machines I run a lubricator to keep the moving parts happy.
    Interesting.. It seems like these are mainly used for medical and laboratory environments but I guess you having no problems in your industrial shop. Any issues with shop air quality causing issues?

    If your feeding multiple machines, do they all require the same PSI or do you go high and they have onboard regulators?

    It seems like California Air Tools makes a variety of similar med/lab style cabinet compressors with built in air dryers for a reasonable price. (It seems these models have generally bad reviews.. I guess your getting what you pay for here. I'm probably better off buying a separate air dryer or something else)
    Last edited by derek labian; 12-25-2021 at 8:26 AM.

  11. #11
    Quote Originally Posted by derek labian View Post
    I guess this is why you have to drain tanks after each use (or so manual says).
    This gets the liquid water that condenses in the receiver. However, the 100% saturated air in Mr. Stankus' example carries on into the air distribution system, finds the next P and/or T drop, and 'rains' again. Rinse & repeat. A auto-drain filter near the point of use helps remove the liquid (by dripping it on our floor, typically), but again the air generally remains saturated all the way to final point of use and discharge to atmosphere.

    A well designed air system, takes this final discharge temperature into account and a drier brings the compressor's discharge dewpoint to this final temperature or less.

    No surprise, Mr. Holcombe has it 'right'.
    Last edited by Malcolm McLeod; 12-25-2021 at 3:54 PM. Reason: semantics

  12. #12
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    Quote Originally Posted by derek labian View Post
    Interesting.. It seems like these are mainly used for medical and laboratory environments but I guess you having no problems in your industrial shop.
    If I recall, that's where Brian sourced his...a medical office of some sort. It's a kewel little unit, too. Kinda like a big end table
    --

    The most expensive tool is the one you buy "cheaply" and often...

  13. #13
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    Quote Originally Posted by derek labian View Post
    Interesting.. It seems like these are mainly used for medical and laboratory environments but I guess you having no problems in your industrial shop. Any issues with shop air quality causing issues?

    If your feeding multiple machines, do they all require the same PSI or do you go high and they have onboard regulators?

    It seems like California Air Tools makes a variety of similar med/lab style cabinet compressors with built in air dryers for a reasonable price. (It seems these models have generally bad reviews.. I guess your getting what you pay for here. I'm probably better off buying a separate air dryer or something else)
    Definitely getting what you’re paying for there. I’m thrifty so I bought my Jun-Air used and repaired a few minor issues. It has no problem running in the shop.

    I ran heavy wall copper, soldered the connections with silver solder for the main runs and have one of more regulator/separator/filter and oiler units at every machine. Some machines I have a separate regulator unit for chip blowers that I run at a different pressure and obviously don’t want the oiler there.

    It was expensive but I have zero regrets. Never had to fight with water in the line, never rust my equipment’s internals, never have water spraying out of a chip blower, never overheated the compressor, Really just don’t have any trouble in that aspect of the shop.

    I researched cheaper machines and decided against them, I hate buying stuff twice.
    Bumbling forward into the unknown.

  14. #14
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    Donít know if this dryer works but if anyone wants it itís free for the taking.
    Attached Images Attached Images
    Steve Jenkins, McKinney, TX. 469 742-9694
    Always use the word "impossible" with extreme caution

  15. #15
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    Quote Originally Posted by Steve Jenkins View Post
    Donít know if this dryer works but if anyone wants it itís free for the taking.
    Shoot. I could use that thing. And Iím going to be in Frisco TX in about 2 weeks. But we will be driving the wifeís car and no way it would fit. Shoot
    The Plane Anarchist

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