fluid cleanliness

Top of Form Bottom of Form Top of Form Bottom of Form Top of Form Bottom of Form Contamination control involves preventing contaminants from entering a hydraulic system and placing filters in strategic locations throughout the system to trap any contaminants that do find their way into the fluid. But for critical equipment, a successful contamination control program also must include regular assessment of the hydraulic fluid's cleanliness. Often, this must be done every two to six months or after every 500 or 1000 hours of operation, depending on the equipment's duty cycle, operating environment, and how critical it is to overall operation. Experts also recommend that fluid be tested immediately after any maintenance event that exposes the hydraulic system to the external environment. This could be when a hose or other component is replaced or fluid is added to the reservoir. Fluid replenishment can be particularly troublesome because new fluid is notorious for being dirty - often from improper storage and handling practices. Test labs or do-it-yourself? Before the advent of portable contamination detection instruments, Figure 1, fluid testing was conducted for only the most critical equipment and sent to a laboratory for analysis. This i s still the most practical route for companies that do not require fluid testing often enough to justify purchasing their own diagnostic equipment and training their personnel. And even if a company has its own equipment, test labs still prove valuable for running multiple tests, interpreting results, troubleshooting, and recommending appropriate action. Test labs should also be consulted for periodic chemical analysis of hydraulic fluid. Even if contamination has been brought to within acceptable limits, certain contaminants can alter a fluid's chemical composition (primarily the additives) and render it ineffective. For example, additive depletion, over time, can reduce a fluid's lubricity, oxidation resistance, or anti-foaming characteristics. Excessive water and overheating are two conditions that can upset a fluid's chemical balance relatively quickly. Therefore, if excessive water is found in a fluid or a system overheats, experts recommend not only finding and correcting the source of the problem, but conducting chemical analysis of the fluid as well. Even if these problems do not occur, hydraulic fluid suppliers generally recommend having fluid analyzed chemically at regular intervals - such as annually - to identify potential problems and prevent them from occurring. Portable particle counters and other diagnostic equipment have made it easy and convenient to monitor fluid cleanliness of even non-critical equipment. In fact, many companies that have invested in their own particle counters and other instruments monitor cleanliness of more equipment more often. The higher reliability that results from this more-intense preventive maintenance adds to the return on their i nvestment. Furthermore, advanced techniques are being developed to make fluid-monitoring instruments even more sophisticated. Equipment currently is under development to continuously monitor the condition of hydraulic fluid while equipment is running. Assessment starts with a sample Fig. 1. Portable contamination detection instruments make it quick and easy to assess the cleanliness of hydraulic fluid, whether the equipment is in an industrial plant or at a job site.

fluid cleanliness

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