A large industrial manufacturer has three large compressors running constantly in the plant. Occasionally during hot summer days, moisture problems occur downstream, so personnel outfitted each compressed air component with timer style condensate drains.
All three compressor have drains on the water separators — this is where most of the water squeezed out of the compressed air accumulates. Two dryers (one main and one spare) have two timer drains each, one on the inlet heat exchanger, and one on each water separator; this is the second most plentiful source of water.
Each dryer has an inlet and outlet filter, timer drains are fitted on each drain. And a drain has been placed on the main receiver, this is a dry tank, but is set to drain just in case.
In all, there are 12 timer drains all firing at random … and during the last heat related water problem, a well-meaning technician set all the drains to operate at 10 second duration every two minutes.
Each timer drain consumes 10 cfm when the discharge opens, this means an average of 20 cfm of drainage occurs. At 10 cents per kWh, this 20 cfm costs $3,855 per year in wasted compressed air!
The real problem in this instance was found to be heat. During hot summer days, the compressor discharge temperatures exceeded the rating of the dryer, and no amount of drainage can solve this problem. The ventilation system was corrected and the water problem went away. The customer used a utility incentive to pay for the cost of airless condensate drains, reducing his drainage costs to zero.
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