Large, aluminum door panels can be difficult pieces to clean. Used in many applications, including the construction of the United States Army's Hummer vehicle as a skin to be placed over the armor plate frame, these panels need to be cleaned quickly and efficiently. This article will serve as an example of how one manufacturer was able to replace an outdated and inefficient washing system with one that cleans more effectively and the steps that went along with the transformation.
The original washer had a load/unload stage of 5', a wash stage of 16', and a spray length of 12'. The overall dimensions of the machine measured out to 7' W x 8'H x 76'L. The machine had a 600-gallon washer tank, a 5,000,000 BTU/hr heater size and design, and a pump size of 481GPM running at 15 PSI. By decreasing some of these measurements and using a more efficient design, the overall design of the washer will be reduced and operating costs will be lowered, along with an increase in production and quality.
First, the loading and unloading stages of the machine will be increased from the original 5' to 8'. By adding three to these stages the operators will have the benefit of increased safety while maneuvering the larger panels. The wash stage will be reduced, from 16' to 12'. The smaller length will make it easier to clean the tanks, as well as keeping the gas burner immersion tube to a minimal dimension. Still, the 12' length will allow a 10' panel to drain before moving on to the next stage in the process. Once loaded, the parts will move through the system in one of two separate lanes, which are both driven by a single, common drive motor. The lanes will consist of flat wire belts on a roller bed, driven by the motor at approximately 8 feet per minute. Adjustable guide rails in the tall lane will allow the machine to handle 3 different widths of the panels.
Spray length will be reduced from 12' to 8'. By decreasing the pump size, from 500 gallons per minute to 300 gpm, but running at a higher PSI, 40 instead of 15, the spray length can be reduced without a drop in wash quality. Since the washer tank has been increased from 600 to 1000, the pump must be size appropriately. Tank volume cannot be less than 3 times the total pump volume or else you can possibly run the pump dry. In the previous configuration, the tank was 600 gallons and the pump was running at 481 GPM, which is not the correct ratio. A 1000-gallon tank and 300GPM pump is more appropriate. The increase in PSI makes up for the decrease in gallon per minute flow and spray bar impingement time. Also, by installing a larger tank, the time before the tank becomes saturated with soil and stamping lubricant is increased, thereby decreasing the amount of time that production must be stalled in order to clean the machine.
In terms of maintenance, the spray stages will also be easier. The pump will be a vertical barrel mount pump, which can be removed without draining the tank. The spray nozzles are quick change, for easy maintenance. The nozzles and headers are customized to optimize the coverage of parts as well.
After the wash stage but before the rinse stage, a blow off feature is installed that was not present on the previous machine. Using a stripping air knife system running at 25 horsepower and delivering up to 600 cfm of air, the parts will be stripped of excess or puddles of water before being sent to rinsing. This stage helps to prevent the cleaner from being carried over to the rinse tank from the wash tank, thereby making the rinsing stage more effective. There will always be wash water rinsed off into the rinse tank, but carrying the water on the part and dumping it into the rinse tank makes the rinse tank just another part of the wash tank and diminishes efficiency and efficacy.
Midbrook Cleaning Systems is a minority owned provider of parts washer and parts cleaner systems, custom metal fabrications, CapSnap water bottling systems, and production cleaning services
By Jamie Knapp
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