Patent ID: 8869883

Claim:
A horizontal frac ball injector, comprising: an injector spool having an intake end, a discharge end and an axial passage that extends from the intake end to the discharge end; and at least two independently operated ball injector assemblies respectively connected to respective radial ports through a sidewall of the injector spool, each ball injector assembly supporting a ball cartridge having a capacity to accommodate a plurality of frac balls, and each ball injector assembly further comprising a ball launcher with a ball chamber having a sidewall, a bottom wall and a side opening in the sidewall, the ball launcher being reciprocated by a ball launcher drive from a ball load position in which a ball is loaded from the ball cartridge into the ball chamber, to a ball release position in which the ball launcher is moved into the axial passage and the ball is moved out of the side opening of the ball chamber by fluid pumped through the axial passage wherein the ball launcher drive comprises a motor that rotates a threaded drive rod which extends into an axial bore in a rear end of the ball launcher, the axial bore extending from a rear end of the ball launcher through a rear side of the ball chamber.