| 摘要 |
PURPOSE: A pipe coupling apparatus of an underground oil storage tank is provided to ensure the tight connection of a pipe coupling apparatus by insertion and fixation of a connection bolt to a part of the pipe coupling apparatus. CONSTITUTION: A pipe coupling apparatus is installed inside the manhole situated on the top of an underground oil storage tank. The pipe coupling apparatus is installed between a withdrawing pipe] and a connecting pipe. The withdrawing pipe is extended from the inside of the underground oil storage tank. The connecting pipe is buried under the ground via a manhole. A recess portion] (13-1a-1) is formed in the inner side of a first connecting protrusion of a pipe holding unit of the pipe coupling apparatus, with a certain width.
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