| 摘要 |
PROBLEM TO BE SOLVED: To improve an expansion efficiency in a capillary tube for a refrigerating/air-conditioning device and prevent the lowering of flow rate of refrigerant, which is due to the adhesion of sludge in the same tube. SOLUTION: A capillary tube 28 is provided with at least one place of projected part 29 on the inner surface of the same to improve an expansion efficiency by the choking effect of refrigerant, which is caused by the projected part 29. The projected part 29 can be formed easily by applying a pushing force from the outside of the capillary tube 28 to deform the same through plastic deformation. On the other hand, the film 30 of a water repellent material is formed on the inner surface of the capillary tube 28 whereby the adhesion of sludge can be reduced remarkably. The film 30 of water repellent material is formed by forming the film 31 of a surfactant on the inner surface of the capillary tube 28, then, the water repellent material is applied thereon whereby an uniform film can be formed while a firing process is applied if necessary in accordance with the nature of the water repellent material.
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