Patent ID: 6997350

Claim:
Apparatus for injecting liquid fertilizer into a water flow line in a sprinkler system, comprising: an injector mechanism body having a water inlet and a water outlet adapted to be connected in the water flow line of the sprinkler system so that water flows through at least a mixing chamber in the body; a liquid fertilizer reservoir; a plunger chamber in one way flow communication with the liquid fertilizer reservoir to allow liquid fertilizer to flow from the reservoir to the plunger chamber, and in flow communication with the mixing chamber; a plunger movably positioned in the plunger chamber; a paddle wheel positioned to be rotated by water flowing through the injector mechanism body; a plunger gear coupled to the paddle wheel and the plunger which rotates when the paddle wheel rotates; and interacting camming surfaces, one of the interacting camming surfaces extending from the plunger gear, the other of the interacting camming surfaces being stationary during normal operation of the apparatus, whereby interaction of the camming surfaces as the plunger gear rotates causes movement of the plunger in the plunger chamber in at least one of two directions, movement of the plunger in one direction in the plunger chamber allowing flow of liquid fertilizer from the liquid fertilizer reservoir into the plunger chamber and movement of the plunger in the other direction in the plunger chamber causing flow of liquid fertilizer from the plunger chamber to the mixing chamber.