Spraying device and method

The invention relates to dust suppression equipment, and provides a spraying device which comprises a liquid supplementing system, a conveying and metering system and a spraying control system capable of atomizing and spraying materials, and the conveying and metering system comprises a hopper, a hydraulic pump, a first flow control switch, a second flow control switch and a metering mechanism. The hopper, the first flow control switch, the hydraulic pump, the second flow control switch and the injection control system are sequentially connected from front to back, and the metering mechanism can meter the flow of materials conveyed to the injection control system. A loop circulation unit can be formed among the hopper, the first flow control switch and the hydraulic pump so that materials conveyed by the hydraulic pump can be lifted to the working pressure for loop circulation, and the liquid supplementing system can supplement the materials to the hopper. According to the spraying device, the spraying amount