SELECTIVE APPARATUS FOR DISCHARGING UNDERSIZED CAUGHT OBJECT FROM TRAWL Russian patent published in 2001 - IPC

FIELD: commercial fishery. SUBSTANCE: selective apparatus has V-shaped partitioning wall, guiding member for directing caught fish mixture to selective apparatus, large-sized fish passage opening and undersized fish discharge opening. Partitioning wall is defined by selective member and guiding member, which are interconnected and positioned at an angle one with respect to the other. Guiding member is adapted for directing undersized fish to trawl outlet end. Selective member has base-frame equipped with set of replaceable selective grids and devices for attaching selective grids on base-frame provided with devices for fixing the position of selective grids. At the moment of joining, frame sizes are equal. Frame of selective grid is fixed on base-frame by juxtaposing it on base-frame so that horizontal axes of section of front and rear (smaller) sides of these frames are extending in single plane and coincide with direction of flow inside trawl sack, with following fixing of grid frame by means of fasteners. Base-frame for selective grids with constant length of smaller sides has constant sizes, and base-frame for grids of different length is made detachable. Such construction allows length of smaller sides to be changed when required. Apparatus may be further equipped with netted selective insert of mirror cell positioned behind partitioning wall, in spaced relation to it, and with member for guiding fish passed through inlet opening to mid portion of selective insert. Selective grid fastening devices are provided with members for restricting motion of frames in vertical and horizontal planes one relative to the other, as well as with attachment units. EFFECT: reduced weight of partitioning wall, improved hydrodynamic characteristics, simplified construction and improved strength of construction. 6 cl, 15 dwg