On Thu, 26 Feb 2009 09:14:03 -0600, Ignoramus19022
wrote:

On 2009-02-26, Milo milo@oil wrote:
"Ignoramus19022" wrote in message
...
On 2009-02-26, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus19022 fired this volley
in :

So, my question is, is that normal behavior at all, do heat
exchangers
add quite a bit to "obstruction", or is there possibly something
with
this air dryer.

If you think that it is a problem, and you have seen it before, I
would love to know what might cause an obstruction like that, maybe
a
bug that crawled in there.

Think of an air dryer as simply a refrigerated pipe. Ideally, it
should cause no more obstruction or friction resistance to flow than
would any piece of pipe that size (with numerous bends in it).

If a 25CFM dryer can't handle a 1/4" fitting, there's obviously
"stuff" in the line -- which is _probably_ why it was offered for sale
in the first place.

Bugs, maybe. Corrosion is likely if the exchanger isn't stainless
steel. Try reversing the flow at a high pressure, and open the
"inlet" as wide as the fitting will allow. You might blow the
obstruction out the way it came in.

The reason why I suspect bugs is that I kept it outside for 2.5 months.

At least you confirm that something bogus is going on.

I did already try reversing air and it did not help.

There are probably more bends in the lines than would permit you to
"roto-rooter" it out. But if the lines are made of stainless, you
could conceivably clean them with acid OR a strong base. Acid if it's
mineral, base if it's organic.

We had a combination dryer/water chiller at the injection molding
outfit I worked for. It had replaceable exchanger coils for each
purpose, immersed in a brine bath that was itself chilled by the
actual refrigeration evaporator. That was a good design for long-term
maintainability.

I will take it apart and see, I think.

Thanks Lloyd, now I at least know that I have a problem.

Before you take it all apart, I'd try adapting a garden hose fitting to the
outlet of the dryer. Maybe some mud daubers got in there. If so, the water
will dissolve there nest and flush it out. You may have to let it "soak"
under pressure for awhile.

Great idea. I will try it for sure. Thanks.

i

Peace
Milo
http://s235.photobucket.com/albums/ee67/mholroyd/



I have also seen dual bed dessicant dryers in instrument air service
in Texas. It would be good to be sure it's not one of those before
you put the water hose to it.

Pete Keillor