Machinery Lubrication

Machinery Lubrication May - June 2018

Machinery Lubrication magazine published by Noria Corporation

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24 | May - June 2018 | www . machinerylubrication.com An infrared camera is one of the best tools for performing regular reli- ability tests on a hydraulic system. It is also invaluable when troubleshooting heat, speed and pres- sure issues. In any hydraulic system, some lines will be at, above and below the oil temperature in the reservoir. e key is to know which lines should be cool, warm and hot. If checks are made when the system is operating normally, a reference can be estab- lished. By regularly conducting the following tests, a faulty component can be found, many times before it shuts down the machine. A schematic for a typical hydraulic system is shown in Figure 1. e circled letters indicate the points in the system that should be shot and recorded with an infrared camera. 1. Check the Suction and Case Drain Lines Check the suction and case dra in lines of t he pump by recording the temperatures at points "A" and "B" in Figure 1. e oil in the "A" line should be very near the oil temperature in the reservoir. e oil that flows out of the case drain line (B), is the oil that bypasses the internal components inside the pump. Most piston pumps bypass 1-3 percent of the maximum pump volume. Vane pumps may bypass as much as 5 percent of the maximum rated volume. For a 30-gallon-per- minute piston pump, the amount of oil in this line should be one-third (1 gallon per minute). Because the oil does no useful work, heat will be generated as the oil bypasses the internal pistons. is line, of course, will be hotter than the oil entering the pump through the suction line. The suction and case drain temperatures are shown in Figure 10 Ways to Check Hydraulic Systems with Thermal Imaging HYDRAULICS Al Smiley | GPM Hydraulic Consulting J C A B D AB RV H G CV HE RF F E M I K ACC MDV To System EDV 12 PSI 2000 PSI PSI 2250 Figure 2. Images showing the suction and case drain temperatures Figure 1. A schematic for a typical hydraulic system "By regularly conducting the following tests, a faulty component can be found, many times before it shuts down the machine."

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