| 摘要 |
PURPOSE:To easily detect abrasions from the outside, by forming a hollow chamber in a section where the sealing material which surrounds a movable body contacts with the movable body with an interval which is equal to an allowable abrasion thickness from the surface of the sealing material, and by detecting leakages of the fluid enclosed in the hollow chamber. CONSTITUTION:A cylindrical body 5 formed in one body with a plural number of individual parts 11 whose ring-shaped supporting wall 10 is projected inward to form an L-shape and which are fixed to the cylindrical body 5, encloses rod packings 6 made of a solid sealing material into the space between a piston rod 3 and the cylindrical body 5. The rod packing 6 is pushed inward by a coiled spring 12 and supported by the supporting wall 10. A part of the rod packings 6' has a hollow chamber 13 alng the partial or whole circumference with an interval which is equal to an allowable abrasion thickness (t) from the enclosing surface, and a fluid which can be detected is enclosed in the hollow chamber 13. Moreover, a collecting chamber 7 which is opened to the atmosphere 9 through a fluid detector 8 is installed between the rod packing 6. When the abrasion of the solid sealing material advances and reaches the limit value (t), the fluid enclosed in the hollow chamber 13 leaks out and the detector 8 detects the leakage and issues and alarm. In this way, no dismantling inspection is required and accurate detections become possible. |
