| 摘要 |
A spiral waveform pipe is provided to expand a bonding area and certainly maintain the whole sealed state of an uneven surface by forming a saw-tooth uneven surface on the outer circumference of a connection hole. A spiral waveform pipe(1) comprises a protrusion unit(1a). The protrusion unit is formed on the outer circumference of the spiral waveform pipe. Two spiral waveform pipes are connected by a connection hole(2). A plastic connection hole has a side-end jaw. The side-end jaw has the external diameter greater than that of the protrusion unit. The connection hole is integratedly adhered to both-end external surfaces of the spiral waveform pipe.
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