Abstract: A pneumatic spraying apparatus and method of operation is disclosed for controlling the flow of pressurized air and fluid material through a spray gun. A material pump is driven through a ratio multiplier by an air motor which is operated by a source of pressurized air. A discharge port in the air motor is connected by an air hose to the gun through a control valve leading to a chamber from which the material is sprayed by air pressure downstream of the valve. Selective operation of the valve controls the downstream air pressure and air flow rate through the gun which in turn modulates air motor speed and torque by controlling the rate of air flow and pressure from the discharge port. This in turn controls the pump speed through the action of the ratio multiplier.

Abstract: A spray system is disclosed which includes a spray gun for the hand-operated spraying of fluid material with pressurized air. A spray gun body includes a barrel chamber having an air tube which directs air outwardly through a discharge port with entrained material in a spray. A bistable control valve operates responsive to movement of a trigger for controlling the flow of both air pressure and material into the barrel chamber. The control valve is bistable in its operation to either close the air flow off when the trigger is in its off position or to open the air flow when the trigger is in any of its operating positions. Air tube adjustment means is provided for manually controlling the spray pattern during operation. An electrical control circuit is provided to control a material flow pump responsive to movement of the trigger.