Importance

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Abstract

A device for feeding a controlled volume flow of liquid to a spray nozzle for automatic spray application. A conduit defines a flow path from a liquid source to the spray nozzle. A displacement pump type member is arranged in the conduit. A driver drives the displacement pump type member with the movable parts thereof with a speed determined by the actual volume flow through the conduit. Elements arranged in the conduit upstream of the displacement pump type member supply the flow of liquid through the conduit to the displacement pump type member and properly feed the liquid in the conduit. A valve is located in the conduit. A regulator regulates the volume flow through the conduit by regulating the throttling degree of the valve means. A first measurer measures the pressure of the flow in the conduit downstream of the displacement pump type member. A second measurer measures the pressure of the flow in the conduit upstream of the displacement pump type member. An arrangement compares the pressure values delivered by the two measurers and on the basis of this comparison controls the regulator to influence the valve for obtaining comparison pressure values corresponding to a volume flow predetermined by the choice of the speed of the movable parts of the displacement pump type member.

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First Claim