A printing plant used intrinsically safe compressed air powered barrel mixers in its ink storage room to ensure the consistency of the color of the company’s products. These vane type air motors ran continuously day and night to keep the ink from separating. A compressed air auditor measured the agitator load and calculated that the total flow consumed was 60 cfm, costing $10,500 per year in electrical costs.
At the time, the Facility Engineer was designing a new ink room located in a different area of the plant. The cost concerned him, so he set about doing research. He learned from his supplier that ink in storage does not need to be continuously mixed but can be left for a considerable amount of time before there is a need to agitate. In his research, he found a design that solved the problem of the continuous flow.
Rather than running all motors at all time, the new design used control valves to shut off the flow to the agitators in sequence. Rather than having all the agitators run at once, the system control ensured that only one motor was running at a time. This reduced the electrical cost to about $880 per year, resulting in a savings of 92%.
Turning off unnecessary compressed air loads is one of the most effective ways to save energy!