| 摘要 |
PURPOSE:To generate a differential pressure for holding a pressure switch by installing a pressure receiving body which corresponding to the pressure difference before and behind an adjusting valve and opening and closing a communication passage to the pressure switch by a plunger linked with said pressure receiving body, in a centrifugal jet pump. CONSTITUTION:In the body equipped with a centrifugal pump 10, jet pump, and a circulating passage, a pressure receiving body 29 which corresponds with the pressure difference before and behind an adjusting valve 22 is installed, and a communication passage 31 to a pressure switch 16 is opened and closed by a plunger 30 linked with said pressure receiving body 29. When a pressure difference is generated, the communication passage 31 is closed, and the pressure switch 16 is held in low pressure state, and ON-state is generated. When the flow rate becomes nearly zero, and the pressure difference is released, the pressure switch 16 is turned OFF. Therefore, a differential pressure can be generated without using a resistor valve for exclusive use, and the number of parts can be reduced.
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