| 摘要 |
PURPOSE:To raise the pump efficiency, by changing the maximum sectional area at the end of the volute of a volute casing of a centrifugal pump by shifting a tongue of the volute casing, and thereby improving matching between an impeller and the casing. CONSTITUTION:A movable tongue 1 is provided in a casing 2 in the manner that it can be slid in a direction x by turning a nut 3. When the top of the tongue 1 is located at a position a shown in the drawing, the maximum area Smax at the end of the volute of the casing 2 is maximum. On the other hand, when the top of the tongue 1 is located at a position b shown in the drawing, the maximum area Smax becomes minimum. Thus, according to the present invention, the value of Smax can be changed freely. Therefore, the pump efficiency can be raised by improving matching between the casing 2 and an impeller 4 by selecting the value of Smax such that the pump can be operated in optimal conditions. |
