FISH PASS Russian patent published in 2007 - IPC E02B8/08 

FIELD: hydraulic structures, particularly fish passes permitting fish passage through support structures to fish hatchery and growth areas.

SUBSTANCE: fish pass comprises fish-passing path created as canal having inlet head connected to upper pool of hydrosystem and outlet head connected to lower pool thereof, oval chambers distributed along fish-passing path in stepwise manner. Mark of each downstream chamber bottom is located under that of upstream one in inlet head direction. Fish pass has swimming-in orifices defined by vertical end chamber parts and side walls thereof, transversal partitions defined by curvilinear parts of side oval chamber walls. Fish-passing path has additional oval chambers and transition chambers. Main and additional chambers are symmetric with respect to transition chambers and are connected with them. Transition chambers are oval in plane view and have central rectilinear channel connecting upstream main and additional oval chambers with corresponding downstream ones. Curvilinear part of side main and additional chamber walls define intermediate chambers connected with each other through swimming-in orifices.

EFFECT: possibility to create hydraulic conditions, which facilitate fish movement along fish pass.

8 cl, 7 dwg