| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of rotations of an impeller for relaxing impact to the impeller, and to improve durability by forming an inflow nozzle provided in a lower inner case with the impeller rotatably in a specific form on upper, left, and right surfaces. SOLUTION: A water meter has a lower inner case 7 where inflow nozzles 9 are formed. The plurality of nozzles 9 are pierced and formed at specific intervals in a circumference direction on a circumference wall 17 of the lower inner case 7. The angle of left and right surfaces 18 and 19 of the nozzle 9 is set so that the side of an inlet outside the nozzle 9 becomes wide, and the side of an outlet becomes narrow. Also, for example, an upper surface 22 of the nozzle 9 is composed of a curved surface 22a lowering from the side of the inlet to that of the outlet, and a plane 22b at the side part of the outlet. Furthermore, a lower side 23 of the nozzle 9 is opened without a wall, thus reducing the number of rotations of an impeller for a flow rate. Also, the loss of pressure in the nozzle 9 is reduced, thus increasing the maximum flow rate without sacrificing the minute flow rate accuracy.
|
