To provide a counter-flow preventive gate equipped with a tilting door, with which an alarm is issued prior to occurrence of a counter-flow in case the door does not rise because of any failure and thereby counter-flow is prevented in advance.
A counter-flow preventive gate is equipped with a door 12 borne in a passage 11 with possibility of tilting and generating a buoyancy under the water and a shutting means to shut the passage when the door 12 is raised, and the arrangement further includes an angle meter 30 to sense the inclining angle of the door 12, a calculating means to calculate the height H of the upper edge 12a of the door 12 on the basis of the data given by the angle meter 30, and a liquid level meter 32 to sense the level (h) of the understream water surface 23 of the door 12, wherein an alarm lamp 33 emits alarm light when the difference between the height H of the upper edge 12a of the door 12 and level (h) of the downstream water surface 23 has becomes below the set value S. Further an automatic door shutting mechanism is furnished which shuts the passage by raising the door 12 with electric power etc. in synchronization with the turn-on and -off operation of the alarm lamp 33.
YAMAMOTO YOJI
YAMAMOTO MASAHIRO
Next Patent: MANUFACTURE OF FILLING, RECLAMATION OR BACKING MATERIAL