| 摘要 |
PURPOSE: To reduce construction cost by sealing a bellows to a pipe attachment by an annular wall, forming the pipe attachment integrally with a casing section having a discharge port piece, and supporting it by an annular shoulder at an end face. CONSTITUTION: The top end of a bellows 3 is furnished with an end wall 33 having a valve seat collar 34, which extends into a pipe attachment 10 of an end wall 7 of a casing section 1, and an annular rib 35 closely surrounding the lower part of the pipe attachment 10. The outside face of the valve seat collar 34 forms a plane 34/3 which contacts to the inside surface of the pipe attachment 10. The valve seat collar 34 forms an annular groove together with the annular rib 35. The bottom face of the groove exhibits an annular shoulder 35/1 by which the end face of the pipe attachment 10 is supported. When the casing section 1 is displaced in an arrow direction 42 to effect discharge operation, a spring 41 develops axial motion orienting to the end wall 7 of a closing part 38. During discharge operation, a lower pump valve 5 is closed, and the medium in the interior of the bellows 3 is discharged outside through a discharge port pipe piece 8 and discharge passage 12 by a discharge-side pump valve 4. |
