| 摘要 |
PROBLEM TO BE SOLVED: To prevent an influence on control of an automatic driving device by a foreign matter by providing a slant portion to form a passage shape of a downstream side communicating passage in such a way that a passage area at a differential pressure chamber side at a side on which a pressure switch is provided is gradually broader than a passage area at a side facing to a discharge side passage. SOLUTION: A valve body 15 is connected to a discharge side of a pump portion 14 to form a discharge side passage 16. A resistor 17 is provided on the discharge side passage 16 and a diaphragm 18a, an upstream side communicating passage 19 and a downstream side communicating passage 20a are provided so as to detect a differential pressure of an upstream side and a downstream side of the resistor 17. A slant portion 20b is provided to form a passage shape in such a way that a passage area of a differential pressure chamber side on which a pressure switch 22 is provided is gradually broader than a passage area at a side facing to a discharge side passage 16. The passage area at the side facing to the discharge side passage 16 is made broader than the passage area of a switch communicating port. Thereby, even if a foreign matter is raised from a water source by a pump, control of an automatic operating device of a pump is hardly influenced by the foreign matter.
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