| 摘要 |
PROBLEM TO BE SOLVED: To provide a multiple pipe and a system for recovering steam from a geothermal well that stably supports an inner pipe on an outer pipe even when a long double pipe is used under a high-temperature environment, where strength of the inner pipe declines.SOLUTION: A multiple pipe 10 recovers steam from a geothermal well GT, and includes an outer casing pipe 1 and a double pipe 4 relatively slidable inside the casing pipe 1 and having a first gap 5 formed between an inner surface of the casing pipe 1 and the double pipe. The double pipe comprises an acid-resistant outer pipe 2 and an alkali-resistant inner pipe 3, and has a second gap 6 between the outer pipe 2 and the inner pipe 3. The double pipe 4 has the inner pipe 3 fixed to the outer pipe 2 at a plurality of fixing locations 8 along a lengthwise direction L leaving an interval. At each of the fixing locations 8, the inner pipe 3 is fixed to the outer pipe 2 partially along a circumference, instead of an entire circumference, so that the second gap 6 ensures flowing of fluid through the double pipe 4 in the lengthwise direction.SELECTED DRAWING: Figure 1 |
