PROBLEM TO BE SOLVED: To provide a stop valve for irrigation water, having a simple structure hardly causing clogging in a pipe (cylinder) for introducing the water, and capable of precisely stopping the water even when turbulent flow is caused by the increase of a flow velocity by downpour or the like.SOLUTION: A stop valve 100 for irrigation water is installed so as to stand between a field and a millrace R. When a water level is at the water level h1 at which the water in the field is little, a float 5 moves upper and lower so as to follow the water level when formed into a water-feeding state by drawing out an inner cylinder 2 from an outer cylinder 1, and when the water level reaches the water level h2 of a proper amount, the inner cylinder 2 is pulled into the outer cylinder 1 to form a water-stopping state.COPYRIGHT: (C)2014,JPO&INPIT【課題】水を導く管(筒)内で詰まりが生じにくく、豪雨等で流速が増して乱流が起きたとしても、確実に止水ができる簡易な構造の灌漑用水止水栓を提供すること。【解決手段】灌漑用水止水栓100は、田圃と用水路Rとの間に起立させて設置される。上記詳細に説明したように、田圃の水が少ない水位h1の時に、内筒2を外筒1から引っ張り出して給水状態にしておくと、フロート5が水面に追従して上下していく。そして、適量の水位h2になると、内筒2が内筒1内に引っ張り込まれて止水状態になる。【選択図】図4
