Foreign material clogging prevention feature

摘要

PROBLEM TO BE SOLVED: To secure a sufficient space for contents to flow in while foreign material capturing effect of a holder for holding a weight for a sucking pipe is improved, and to simplify the structure of the weight holder. ;SOLUTION: Projecting parts 13c for preventing the intrusion of foreign substance are formed on four concentric circles surrounding an inlet 13d of a sucking pipe in the inner peripheral surface 13a of the weight holder 13. The gap between the projecting parts 13e adjacent to each other is narrower than the minimum inner diameter of the sucking pipe 11, the lower end part 13g of each projecting part 13e abuts on the weight 12 and the length from the inner peripheral surface side end part 13f to the lower end part 13g is longer as the flow-in passage 13b side. Because the foreign substance passed forcibly through the gap of the projecting parts 13e in the flow-in passage 13c side further receives the filter action in the gap of the projecting parts 13e in the downstream side thereof, the foreign substance is surely captured. Many routs for the contents to the sucking pipe 11 are present and a passage 13h between the projecting parts 13e has sufficient length and then even when the gap between the projecting parts are clogged with the foreign substance, the contents is passed through another rout or a space part between the projecting parts where is not clogged with the foreign substance yet to flow-in to the sucking pipe 11.;COPYRIGHT: (C)2003,JPO