Modular ball drop

A modular ball drop module, comprising:

• having a top end and a bottom end, the top end comprising a tubular body having a central passage, the top end adapted to be mounted to one of another ball drop module and a purge valve;
• and the bottom end connected to the top end and having a central passage of the same diameter and aligned with the central passage of the top end, the bottom end being adapted to be mounted to any one of:
• another ball drop module, a frac head and a frac iron;
• a ball retainer mechanism housed by the tubular body and obstructing the central passage of the tubular body when the ball retainer mechanism is in a ball retention position, the ball retainer mechanism being movable from the ball retention position to a ball released position in which the central passage is unobstructed;
• and
• an actuator stem lock mechanism that automatically locks the ball retainer mechanism in the ball released position when the ball retainer mechanism is moved from the ball retainer position to the ball released position.

A modular ball drop with at least two ball drop modules, the respective ball drop modules comprising:

• a central passage that stores frac balls to be dropped by a ball retainer mechanism of the ball drop module, the ball retainer mechanism comprising a retainer ball that obstructs the central passage in a ball retention position and in a ball released position opens the central passage to let the frac balls drop through the central passage of the ball drop module;
• an actuator stem connected to the ball retainer mechanism, the actuator stem being adapted to rotate the ball retainer mechanism from the ball retention position to the ball released position;
• and
• an actuator stem lock mechanism that is constantly urged to lock the actuator stem in the ball released position.