UNDERGROUND FIRE HYDRANT Russian patent published in 2001 - IPC

FIELD: water supply systems. SUBSTANCE: proposed hydrant has column installed on fire support, nut, rod and valve. Lower part of column is provided additionally with cylindrical branch pipe of diameter corresponding to diameter of fire support passage section and length not exceeding half-of column radius. Upper part of branch pipe is provided with inner ring projection on lower surface of which wedge-shaped ring slot is made to receive ring sealing gasket. Nut is secured on column, and vertical rod is provided with thread turned into nut. Valve is secured on lower shank of rod and is made in form of cylindrical cup with central hole in bottom and with upper edge corresponding in shape and diameter to ring slot of branch pipe. Height of cup corresponds to length of branch pipe. Lower shank of vertical rod is passed with clearance through central hole of cup installed for vertical displacement along shank of rod over distance limited by two thrust nuts located on rod shank over and under cup bottom, respectively. At least three centering projections for cup are made on inner surface of branch pipe. Sealing washer is installed on shank between cup bottom and lower thrust nut. Flexible element made in form of leaf compression spring and resting by its ends on cup bottom is secured by its middle part on rod shank under lower thrust nut. EFFECT: prevention of hydraulic impacts, reduced cost of maintenance in operation, improved reparability. 1 dwg