The device (1) has a ramp (5) with multiple sections (6) respectively comprising nozzles (8) to spray a liquid product (2) from a supply tank (3). A centrifugal supply pump (10) has an inlet port (10.1) connected to the tank, and a discharge port (10.2) connected to a supply pipe (9) that is connected to the ramp. A discharge pump (22) e.g. diaphragm pump or compressor, has an inlet port (22.1) connected to a fluid tank (20) e.g. washing tank or compressed air accumulator, and a discharge port (22.2) connected to the supply pump's inlet port. The fluid tank contains water or compressed air. An independent claim is also included for a method for spraying a liquid product on a surface such as agricultural land.
