Up Time Magazine- April/May 2008 - (Page 28) lubrication upload Preparing for Mothballing A Vital Procedure for Protecting Industrial Equipment by Mike Galloway W hile most companies recognize the importance of routine maintenance for their expensive and complex industrial equipment, many risk permanent damage to that same equipment when they fail to take appropriate steps to “mothball” the equipment when preparing for temporary or extended shutdowns. The risk is real: equipment that is not properly mothballed can quickly show signs of internal metal corrosion that will significantly reduce component life and cause start-up problems when the equipment is brought back into service. insoluble contaminants out with it. If the lubricant/ cleaner mixture is allowed to cool, contaminants may fall out of the mixture and remain in the system after shutdown. These contaminants may then cause corrosion on internal metal surfaces. The lubricant/cleaner mixture should then be disposed of in an environmentally friendly manner through a company that provides industrial waste management services. After the equipment has been drained and allowed to cool, the machine should be completely wiped down using lint-free rags. The equipment’s filter elements should be replaced and all strainers cleaned to prevent contaminants from affecting the machine. Next, the system should be refilled to capacity with a three-phase rust inhibitor lubricant. This lubricant will protect the machine’s internal surfaces by giving them a light coat of oil. The lubricant also will protect any internal surfaces that are submerged in oil (liquid phase), and protect surfaces that do not come into direct contact with the lubricant (vapor phase). The equipment may need to be briefly restarted to circulate the lubricant to ensure that all internal components have been coated. Once the machine has been stopped, the operator should plug the system to prevent the release of any rust-inhibiting vapors. This is done by replacing all the machine’s breathers with pipe plugs, sealing the fillcaps and any vents, and taping any seals. To complete the mothballing process, the machine should be tagged with a prominent label (preferably red) stating, “This equipment has been mothballed. You must take necessary steps to prepare the system for restart.” Strong consideration should be given to listing the actual steps required for restart, as well as contact information for the machine operator who performed its shutdown. Philosophy of Mothballing The three biggest threats to equipment that is taken out of service are: • Moisture/water build-up inside the machine that can break down into acids that cause internal corrosion; • Vibration from external movement causing microwelding of contacting surfaces (better known as fretting corrosion); and, • Foreign contaminants (dirt, rust, cigarette ash, etc.) that can cause abrasive wear on rolling elements. Properly mothballing equipment can help protect against these threats. It will allow a piece of equipment to be brought back into service when needed, quickly and easily. By following the steps outlined below, companies can protect their financial and time investments in their industrial equipment when storing or temporarily shutting it down. System Preparation for Mothballing Approximately 24 to 48 hours prior to equipment shutdown, machine operators should change filters and then add a system cleaner. It is important to remember to change the filters before adding the system cleaner in order to prevent the cleaner from breaking up contaminants already in the filters and spreading them back into the system. The system cleaner should be added at a mix equal to approximately five to 10 percent of the machines existing lubricant, to help clean the machine’s system. However, it is best to check with a lubricant supplier for their recommendations on the best system cleaner and the amount to use for a particular piece of equipment. Once equipment is shut down, it should be drained completely, including the breaking of all low-lying lines. The mixed lubricant/cleaner mixture must be drained from the machine while still hot because it will carry 28 april/may 2008
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