| 摘要 |
PROBLEM TO BE SOLVED: To provide a sand seal device capable of early detecting intrusion of muddy water and excavation sand into a seal chamber, by directly monitoring mixing-in of an impurity to lubricating oil.SOLUTION: A sand seal device 40 of a shield machine comprises a plurality of stages of sand seals (a first sand seal 41, a second sand seal 42, a third sand seal 43 and a fourth sand seal 44), and prevents intrusion of muddy water and excavation sand from the working face side by supplying and filling lubricating oil to a seal chamber (a first seal chamber 51, a second seal chamber 52 and a third seal chamber 53) formed between longitudinally adjacent sand seals, and comprises an extraction pipe 61 for extracting the lubricating oil from the first seal chamber 51, and mixing-in detection means for detecting an impurity (a soil particle) mixed in the lubricating oil extracted by the extraction pipe 61. |
