Rock drill bit and a check valve therefor

A rock-crushing rotary drill bit comprising:

• a bit body forming at least one leg;
• and
• a rotatable roller rotatably mounted on the at least one leg by bearings, the roller including rock crushing elements;
• the bit body further including:
• an external thread adapted for connecting the bit body to a drill tube,
• a main channel for conducting flushing medium,
• a first flushing channel passing through the at least one leg and communicating with the main channel for conducting flushing fluid therefrom to flush the bearings,
• a second flushing channel communicating with the main channel and including a discharge recess for discharging flushing medium from the bit body, the discharge recess defining a linear center axis,
• a nozzle disposed at a downstream end of the discharge recess for directing flushing medium in a direction to flush-away cuttings, and
• a valve element disposed at an upstream end of the discharge recess and including a guide structure for guiding the valve element in linear movement along the center axis, the valve element being spring-biased to a closed state for closing the discharge passage, and being yieldable in response to fluid medium pressure acting thereagainst, for opening the discharge recess.