| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a backflow preventing structure of a boost water supply device improving the installation property of the boost water supply device. <P>SOLUTION: The backflow preventing structure is provided with a backflow preventing device comprising a primary side check valve 21 for primary side backflow prevention with a larger pressure reducing effect than a check valve 6 on the discharge side of a booster pump part 3, on the suction side of a booster pump part 3 to doubly regulate backflow from the water supply side to the distributing main side by diverting the check valve 6 to secondary side backflow regulation, and a discharge mechanism 25 for discharging water from the secondary side of the primary side check valve when primary side pressure and secondary side pressure with the primary side check valve 21 held between are in an equal pressure state. With this constitution, since components of a pump unit 1 serve as both the exclusive secondary side check valve part and an intermediate chamber required in a conventional backflow preventing device, the backflow preventing device 20 can be miniaturized, and the degree of installation freedom of the boost water supply device can be improved. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
