| 摘要 |
PURPOSE:To stabilize performance by forming the inside diameter of a gradually expanding passage greater than the inside diameter of a parallel passage at the connecting part of said gradually expanding passage to said parallel passage of a Venturi tube and preventing change in a water passage section and rapid change in flowing condition due to the dimensional error of a mold. CONSTITUTION:At the connecting part of a parallel passage 34B to gradually expanding passage 34C in a Venturi tube 34, the minimum inside diameter D of the gradually expanding passage 34C is made larger than the inside diameter (d) of the parallel passage 34B. For this dimensional difference, a proper value can be determined by calculating the eccentricities of the mold on the parallel passage side 34B and the mold on the gradually expanding passage 34C side, to carry out molding. Thereby, even if an eccentricity exists in a mold, a step part is not formed at the inlet of the gradually expanding passage 34C as in the case of a conventional example, introducing a flow from the parallel passage 34B smoothly into the gradually expanding passage 34C. As a result, a uniform flow can be obtained and the performance of a jet pump can be stabilized at a high level, keeping high reliability. |
