| 摘要 |
PURPOSE:To perform sure sealing by sealing a neck for sealing both the primary side and the secondary side of a filter with pressure welding force based on the change in diameter due to the change in temp. CONSTITUTION:Two kinds of aperture parts 41, 42 having different diameters are provided to the lower end of a filter housing and an annular projection 43 properly projected to the inner part is integrally formed to the large-diameter aperture part 42. On the other hand, a neck 51 integrally made to a filter structural body 1 is formed into large diameter for the inside diameter of the projection 43. Therefore the neck 51 is made to small diameter and the aperture part 42 is made to large diameter by heating or cooling and thereafter both are inserted: when both have been made to ordinary temp., the annular projection 43 and the aperture part 42 are welded with pressure. As a result, the primary side in the housing 21 is completely sealed to the central aperture 35 shown by a dotted line in the neck 51, namely the secondary side. |
