Being the back flow prevention device for the public measure which is installed in the public measure itself which formed with the cleaning hole

摘要

PROBLEM TO BE SOLVED: To easily install a backflow preventive device in an existing public basin, for preventing backwardly flowed waste water from jetting out of a drain facility.;SOLUTION: This backflow preventive device has a substantially cylindrical backflow preventive device body 15 having an outer diameter substantially equal to an inner diameter of an inflow side connecting port 2 of a public basin body 1. The backflow preventive device body 15 is provided with a valve element 16 opening toward the inside of the public basin body 1 by the water water flowing in from an inflow side connecting pipe 12, and an installation part 26 of an installation device for inserting and connecting the backflow preventive device body 15 into and to the inflow side connecting port 2 from the inside of the public basin body 1. A support bar 20 is connected to a support object part 21 formed in the backflow preventive device body 15, and the support bar 20 is provided with a bending part 23 for forming a support bar holding part 22 having the length substantially equal to an inner diameter of a cleaning port of the public basin body 1 from an upper end part.;COPYRIGHT: (C)2007,JPO&INPIT