Ball injector for frac tree

Abstract

A ball injector for connecting below the frac head of a frac tree to accommodate and sequentially drop a ball into the axial passageway of the frac tree. The ball injector has an axial passage of an injector housing aligned with the axial passageway of the frac tree. A ball cartridge assembly stores one or more balls and sequentially delivers one ball to a port in the ball cartridge assembly. A ball launch side arm extends from the injector housing and forms a ball launch passageway communicating between the ball cartridge port and the axial passage. A first valve member in the ball launch passageway is opened to pass the ball into the axial passage, and is closed to isolate the ball cartridge assembly from a pressure in the axial passage. A second valve member between the first valve member and the ball cartridge assembly may be included to form a pressure isolation chamber between the valve members. Embodiments of ball cartridge assemblies to horizontally store a plurality of balls is provided. Also provided is a method of delivering a ball into a frac tree below the frac head, and a method of delivering and monitoring a ball progression into the frac tree, for example with a camera.