A production supervisor was making his rounds one day when he gingerly stepped around a key conveyor belt. At the end of the belt, some water was being thrown off the belt surface and formed a puddle on the floor, causing a slip hazard.
Not noticing the danger, the supervisor fell on his butt in front of his people. After wiping himself off and sheepishly acknowledging the stifled laughter, he ordered that something be done about the problem — NOW!
Thinking that compressed air was free, his maintenance crew rigged up a system of compressed air nozzles to blow on the belt to dry it. This solved the problem and satisfied the manager — however, the powerhouse supervisor was not so happy. This supervisor knew that compressed air was not free; in fact, because the air was produced at 120 psi and dried with desiccant dryers, the power consumption was 23 kW for every 100 cfm used.
Getting out his calculator, and using the blow nozzle specifications, the cost for the 250 cfm of compressed air for this application — which was left to blow uncontrolled 24 hours per day — was about $50,000 per year. This one blowing application consumed about 70 hp of compressor capacity, or one third the average plant air demand.
The production supervisor was introduced to the economics of the situation and the problem was quickly corrected by redesigning the conveyor water collection and drainage system. This was something that cost less than $1,000.