Moisture in electrical cabinets, control panels and motor compartments can affect plant efficiency and product quality, leading to significant downtime and expensive repairs. This is especially critical in food processing industries, since moisture can lead to mold and/or bacterial growth and create regulatory concerns. Purging the compartment with air dried by a system using a filter and membrane provides a reliable solution with considerably lower initial and operating costs. The system can be used on a 24/7 basis even during washdown procedures (when drying is most needed).
Removing water vapor from air via a filter and a membrane
Water, compressor oils and particulate matter can be removed from compressed air (input temperature range =40-120oF and the input pressure range = 60-150 psig) using a coalescing filter and a hollow membrane module. The coalescing filter removes water droplets, oil and particulate materials with an efficiency of 99.99% at 0.01 µm and the hollow membrane fibers remove water vapor to provide dry air with a dew point of -7oF from saturated inlet air of 100oF and 100 psig.
Using a cabinet dryer avoids downtime
Cabinet dryers have no moving parts and require minimum maintenance; periodic replacement of a filter can be performed during routine system shutdowns. As an example, a meat processing plant in the Midwest that used a heater to keep a control panel dry found that it was replacing the keypad every three weeks. After it replaced the heater with a cabinet dryer, it was possible to operate for six months or more at a time with no failures, replacing the filter on a routine maintenance basis.
A similar cabinet drying system was installed on a metal detection system at Dan’s Prize, a division of Hormel Foods Corporation. Before the dryer was employed, it was necessary to stop production three times a week to remove moisture from the detector. According to Tom Breslin, Manager of Plant Engineering, “once we installed our dryer system, the problem went away. The dryer has been in place for about a year, with no maintenance issues.”
Dried compressed air reduces operating costs
The operating cost of a filter/membrane based system is considerably lower than that of alternative systems. As an example, Lee Clarkson, production engineer at Ross Industries in Midland VA, a manufacturer of meat tenderizers, food packaging equipment, and food processing systems, reports “essentially no operating costs for the membrane dryer once the system is installed, except for annual cartridge replacement. In the case of the meat processing plant discussed above, a saving of about $25,000/year was obtained from eliminating the need to replace the control panel and from down time during the replacement time.”
Conclusions
The filter membrane system provides an effective, reliable and inexpensive approach to the problem of mold or premature component failure due to moisture. The system does not require electricity, has no moving parts and can be used on a 24/7 basis, even during washdown procedures. The combination of a coalescing filter and a membrane filter provides air with a dew point of -7oF and a relative humidity of 10% or less, ensuring that cabinets will be kept bone dry.
