Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1061099
16 | November - December 2018 | www . machinerylubrication.com e philosophy at many plants is that if the hydraulic system is operating the machine, don't mess with it. Frequently, the only hydraulic maintenance ever performed is changing the fi lters, checking the oil level and performing oil analysis. I recently consulted with a corrugated box plant where the return fi lter had not been changed since the plant started up 17 years ago. When a hydraulic issue occurs in a plant, it normally is fi xed by a parts-changing process. is is expensive in the cost of the parts and plant downtime. All mainte- nance personnel should have the knowledge and skills to troubleshoot and maintain in-plant systems. e following are four things every hydraulic troubleshooter needs to know. 1. The Function of the Components When a hydraulic problem occurs, the machine is visually inspected for busted hoses, pressure on the gauge, low oil level and if the electric motor is tripped out. If nothing obvious is found, a parts-changing process begins. Guess which component is usually changed fi rst? If you said the hydraulic pump, you'd be right. One of the biggest misconceptions is that a pump supplies pressure. Pumps deliver volume or fl ow. Pressure is only created when there is resistance in the system. Many a good pump has been changed because the gauge showed little or no pressure. is is a perfect example of the hydraulic troubleshooter not knowing the function of the pump in the system. Before any troubleshooting begins, maintenance personnel should understand the function of all the system's components. ey can't always be identifi ed simply by looking at them. One valve may look like another but perform an entirely diff erent function. Many valves have a symbol on the housing tag to indicate the type. is is the easiest way to distinguish valves, but it is of no use if the maintenance person isn't familiar with hydraulic symbols. 2. Troubleshooting Procedures A hydraulic troubleshooter must know the proper procedure for verifying whether a component is good or faulty. In most cases, a quick check or test can be performed. For example, to assess whether a fi xed- displacement pump is badly worn, check the oil fl ow out of the relief valve's tank line. With the pump off and the electric motor locked and tagged out, remove the tank line of the relief valve and port it into a container of a known size. Time the fl ow for one minute. e pump's rated fl ow should fi ll the container in one minute's time. If the pump volume is larger than the container, an alternative method can be used. Fully turn the relief valve adjustment counterclockwise. Next, turn on the 4 Things Every Hydraulic Troubleshooter Should Know HYDRAULICS Al Smiley | GPM Hydraulic Consulting "All maintenance personnel should have the knowledge and skills to troubleshoot and maintain in-plant systems." Valves located in a stack may look alike but perform completely diff erent functions.