| 摘要 |
PROBLEM TO BE SOLVED: To provide a semi-open impeller capable of further improving pump efficiency while allowing a foreign substance with a desired size to pass therethrough.SOLUTION: A semi-open impeller 80 includes a base part 81 and first and second blades 90, 100, and an inside part 86 and an outside part 87 are regulated. An interval between adjacent blades along a virtual circle around a rotational axis of the first and second blades 90, 100 is gradually expanded from the rotational axis X side toward the outside. In the second blade 100, a length L3 of a first part 103 corresponding to the inside part 86 along the rotational axis X is a length allowing a virtual sphere 200 to be stored between the inside part 86 and the bottom 26a of a pump chamber 21 along the rotational axis X. In the second blade 100, a length L4 of a second part 105 corresponding to the outside part 87 along the rotational axis X is a length allowing the virtual sphere 200 to be stored between the outside part 87 and the bottom 26a along the rotational axis X and is longer than the length L3 of the first part 103. |
