WorldWide Drilling Resource

21 WorldWide Drilling Resource ® NOVEMBER 2014 Hydraulic Training by J. Eric Freimuth Hydraulic Training Associates Revisiting System Cleanliness Part 1 Let’s revisit system cleanliness, which was discussed in the WWDR April 2013 System Cleanliness is Primary article. Cleanliness is the primary means of ensuring satisfactory hydraulic sys- tems life. The oil and all parts of the system must be kept very clean at all times. Failure to perform preventive maintenance can result in the system’s components being damaged or fail com- pletely. There are a number of preven- tive maintenance procedures that help eliminate many potential problems, and these procedures must be performed on a regular basis. With pumps and valves designed to closer tolerances and finer finishes, fluid systems operate at ever-increasing pressures and efficiencies. These com- ponents will perform as designed, as long as the fluid is clean. Oil cleanliness results in increased system reliability and re- duced maintenance. As particles are induced or ingressed into a hydraulic system, they are often ground into thou- sands of fine particles. These tiny par- ticles are tightly packed between valve spools and their bores, causing the valve to stick. This is known as silting. To prevent silting, early component wear, and eventual system failure, engi- neered filtration is required. This includes understanding the required micron rat- ing, application of the beta ratio, maintain- ing proper ISO code cleanliness levels, and filter location specific to system de- sign and environment. In sealed-reservoir systems, chang- ing the hydraulic fluid every 2000 hours of operation is generally adequate. A more frequent fluid change is required if the oil has become contaminated by water (indicated by a milky appearance) or by other foreign materials, or if it has been subjected to abnormal operating conditions, such as excessive temper- ature. In an open-reservoir system which uses an air breather filler cap, the hy- draulic fluid should be changed after approximately 500 hours of operation. When changing the oil, always clean and flush the reservoir before refilling, and use only clean, prefiltered fluid. Be sure to consult your maintenance man- ual for the proper fluid to be used based upon manufacturer specifications. Be watching for our next articles as we will be discussing micron size, beta ratio of filters, ISO code understanding, reservoir size, and much more. Our goal is to help owners, operators, and mechan- ics understand the importance of proper system maintenance and the value of keeping it running properly. If you don’t have proactive fever, remember, this relates directly to cost and downtime. Eric Eric Freimuth may be contacted via e-mail at michele@wwdr-usa.com " ; # 511-,(2 0) 20'5&43 %9 4+(3( ,/( $/5)$&452(23 ; 08 029'0/ # ! : : $8 $,- 3$-(3 *,6(/3,/4(2/$4,0/$- &0. "(% ,4( 777 *,6(/3,/4(2/$4,0/$- &0.