NON-RETURN VALVE OF DRILLING BIT WITH AIR BLOWING Russian patent published in 1998 - IPC

FIELD: drilling machinery and equipment. SUBSTANCE: this is intended for use in mining industry in drilling bore-holes with air blowing. Valve has hollow body with side openings and flaps which are movable, spring-loaded relative to each other and are in contact with side openings. Inner space of valve body is made widening towards its lower part. Flaps are inclined with respect to body axis. Incline of back surfaces of flaps in closed position is not less than 4 deg. Valve can be provided with bypass nipple made in the form of perforated pipe connection which is blanked at one end, and also with additional valve in the form of flexible pipe secured for possible covering of perforations. EFFECT: higher efficiency. 1 cl, 3 dwg