| 摘要 |
PROBLEM TO BE SOLVED: To detect the internal leakage of a hydraulic cylinder easily by a contactless or contact method from the outside by stopping a piston in the approximately center position of a cylinder tube, measuring the outer surface temperature of the cylinder tube, and informing when the temperature difference of measuring positions is larger than the specified threshold value. SOLUTION: A piston 4 is positioned into an approximately center position of a cylinder tube. When maintaining specified oil pressure by a hydraulic pump 1, the outer surface temperature of the cylinder tube is measured by an infrared camera 8, and the measured result is transmitted to a computing element 9. The computing element 9 selects the temperature of measuring positions (a), (b), (c), computes the difference (tb -t1 =Δt) between the temperature tb of the selected position and the lower temperature t1 between the position (a) and the position (c) and compares previously inputted temperature difference threshold valueΔtp with the differenceΔt. In case ofΔt>Δtp , the computing element 9 outputs an alarm command or a lighting command to an alarm 10 or an alarm lamp 12, and the computing element 9 transmits a computed result to a display 11.
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