Page 76

With cooler weather on the way, you may not be too worried about rising oil temperatures, but the fact is, any industrial hydraulic system running higher than 140 degrees is too hot. Consider that for every 18-degree increase in temperature above 140 degrees, the life of the oil is cut in half. Systems that operate at high temperatures can produce sludge and varnish, which result in the sticking of valve spools. Pumps and hydraulic motors bypass more oil at high temperatures, causing the machine to operate at a slower speed. In some cases, high oil temperatures can waste electrical energy by making the pump drive motor pull more current to operate the system. O-rings also harden at higher temperatures, leading to more leaks in the system. So what checks and tests should you perform if the oil temperature is higher than 140 degrees?

There are five essential hydraulic tools that most people don’t have when troubleshooting hydraulic problems in the field. Most of these tools are well-known by maintenance crews. They are often overlooked when it comes time to troubleshoot a problem. Having these essential hydraulic tools will reduce on the amount of downtime that may occur, as well as reduce the amount of money spent on components that are changed without first verifying that they have failed.

Often the only tests and actions performed on a hydraulic system involve changing the filters, sampling the oil and checking the oil level. As long as the system is operating, the mentality of “if it ain’t broke don’t fix it” frequently prevails. However, on any given system in your plant, you should perform 15 to 20 regular reliability tests while the system is operating. There are also several checks and procedures that should be completed during shutdowns or down days. The following preventive maintenance and reliability tests can help improve the efficiency and operation of your hydraulic systems and machines.

“Should oil analysis be applied to all plant rotating equipment or just the critical equipment?”

This is a common question throughout industry. Unfortunately, there are no formal maintenance guidelines that provide specific answers. The decision of whether to perform oil analysis on certain equipment will be based on a number of factors in your facility’s asset management cycle, including the maturity of the maintenance and asset management programs. The more advanced the program, the more predictive/proactive resources may be used, including advanced oil analysis.