| 摘要 |
The present invention relates to a water-raising column for pumping consisting of plastic tubes 3, 4 particularly made of polyvinyl chloride, inside which a string of rods 5 extends. This water-raising column is characterised in that the tubes 3, 4 constituting the water-raising column are joined by means of coaxial coupling sleeves 6 in which are engaged the end parts of the tubes 3, 4, each coupling sleeve 6 comprising a median part 6a which has an internal screw thread 6b into which are screwed external screw threads 3a, 4a provided on the end parts of the tubes 3, 4, the median part 6a of the coupling sleeve 6 being extended upwards and downwards by two end parts 6c, 6d with a smooth internal surface. <IMAGE>
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