| 摘要 |
PROBLEM TO BE SOLVED: To provide a natural ventilation structure for an underground box, wherein the box is made compact so to easily bury along a road when housing a transformer in the box for distributing low-tension electric power. SOLUTION: A pillar for an illumination lamp 22 or the like is shared with the use as a cylinder for ventilation. Ventilation holes 5 are provided on the side faces and the top of the multipurpose pillar 23, and the underground box 2 that houses the transformer 4 is connected to the multipurpose pillar 23 with a ventilation pipe 10. The underground box 2 and a rain-water box 1 having ventilation holes 5 are mutually connected with a ventilation pipe 10. The natural ventilation structure is based on a mechanism that depends on the temperature difference, which is generated by the height difference in the ventilation holes 5, wherein cold air comes into the lower holes and warm air goes out from the upper holes. A sand reservoir that reserves the rain water and sand or dirt flowing into the rain-water box 1 is divided into an upper part and a lower part by a fine-mesh dust-eliminating filter plate 17. The upper part reserves sand and dust while the lower part serves as a rain-water storage vessel to reinforce the cooling of the air by the evaporation of the rain water. COPYRIGHT: (C)2005,JPO&NCIPI
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