After-Cooler Question

[sp8zzz2]

Hello, First-time poster here.
I am getting ready to instal an after-cooler to our 7.5hp Atlas Copco compressor.
I've read many posts on the forum here and have a familiarity of what to do.
I have purchased the Hayden 1290 oil cooler, Wilkerson auto-drain, and Pabst 230v. electric fan. My first question concerns the placement of the Hayden cooler. My original plan was to mount it to the wall above and behind the compressor so the intake will be about 30" above the discharge or output of the compression housing. Some posts I have read suggest that the line coming out of the discharge should be downhill so that any condensate in the plumbing will not run back into the compression cylinders. I've seen some setups on this forum that do not adhere to this rule and am wondering if this is a major faux pas.
My second question has to do with desiccant filters. I've seen setups with and without one. What is the best practice?

 

[metlmunchr]

Use an inline check valve between the compressor discharge and the cooler and you can put the cooler at whatever elevation you prefer.

Re the dessicant dryer...... Air coming out of your cooler will be saturated at whatever temperature the air exits the cooler. Saturated means the air will be at 100% relative humidity for that temperature. Further cooling down the line will result in more moisture condensing out of the air.

What you'd normally do is put another moisture separator ahead of the dessicant dryer, usually at the point of use in cases where you're using a small dessicant dryer.

All this begins to add up money-wise, particularly in a business where there's labor costs associated with the installation and ongoing maintenance such as monitoring, changing, and drying the dessicant beads for reuse. You rapidly reach the point where it makes more sense to spend a thousand dollars on a refrigerated air dryer and forget all the other stuff. A refrigerated dryer will reduce the air's dew point to less than 40°F and re-warm the air before it leaves the unit, giving you air that's suitable for use without further drying, as well as eliminating long term corrosion issues within the piping system due to condensation.

 

[pcmeiners]

"My second question has to do with desiccant filters. I've seen setups with and without one. What is the best practice? "

I have a desiccant filter made from an A/C dryer for mobile use, it has about a 2 gallon bead capacity, approximately 15x the capacity of filters going for hundreds. Desiccant filters are not very practical and work best with a cooler such as the 1290 before them. As is a 1290 will removed approx.70% of the moisture. If you can mount the 1290 in front of the compressor pulley, no need for a fan. If you do go for a desiccant dryer, "Fresh Sent" cat crystals (non scented) is a cheap source of desiccant.

 

[Cyclotronguy]

I have a refrigerated air dryer and the 40 degree F dew point is very workable for 9 months out of the year.

On days like today, when it's raining and the ambient temp is 39 F, it's not so useful; which is why all the drops have Milton desiccant dryers. The belt and suspenders approach.