Patent ID: 7431053

Claim:
An inner-space-sectioned tube in which at least two lengths of first and second inner tubes are provided inside an outer tube of a cylindrical round form having the same cross-section over its entire length, comprising: outer sealing portions being formed on an outer peripheral surface of said first and second inner tubes in contact with said outer tube, the outer sealing portions being partly concentric relative to the inner peripheral surface of the outer tube; an inner sealing portion formed where said first and second inner tubes oppose to and contact with each other; said first and second inner tubes including link segments connecting an end of each of said outer sealing portions to an end of said the inner sealing portion; and, at least one subspace that is enclosed by link segment of a first inner tube, a link segment of the second inner tube and a segment of the inner peripheral surface of the outer tube, wherein said outer sealing portions are made longer in segmental length than said inner sealing portion; a hole communicating said outer sealing portions with the outside of the outer tube by machining; and each said link segment extends in a radial direction relative to said outer tube.