Spray chamber and system and method of spray coating solid particles

Abstract

A system for applying liquid to solid particles is provided including a constant volume apparatus having a chamber and an aperture arranged to deliver the particles in a substantially constant volume stream to a moving surface such as a conveyor belt. A mass flow-measuring device having a receiving end positioned adjacent the moving surface whereby the constant volume stream flows through the mass flow-measuring device and engages a curved sliding surface of a discharge pan, the curvature discharging the particles from the mass flow-measuring device in the stream at an angle from vertical. A liquid application chamber is positioned below the pan and has an internal passageway with an inlet positioned to receive the stream of particles flowing from the mass flow-measuring device. The passageway is defined by at least one curved wall. The curved wall has an upper portion positioned at an angle approximately identical to the discharge angle of the pan to receive the stream of particles in sliding fashion. The curved wall continuously curves downwardly to vertical and continues its curvature beyond vertical to an exit angle from which the particles exit in the stream. At least one liquid dispensing apparatus is positioned to dispense liquid onto the stream of particles as the stream moves through the passageway.