Multifunctional simple spray gun

The utility model relates to a chemical wastewater, waste liquid and waste gas treatment device, in particular to a multifunctional simple spray gun which is used for conveying waste gas and waste liquid for a boiler and comprises an inner pipe and an outer pipe, and a spray head is arranged at the end, close to the boiler, of the inner pipe. A pressure pump and a pressure gauge are arranged at the end, far away from the boiler, of the inner pipe; an outer pipe is arranged at the end, close to the boiler, of the inner pipe, and the diameter of the outer pipe is larger than that of the inner pipe. The spray gun is further provided with a first compressed air pipe and a second compressed air pipe which are perpendicular to the outer pipe, and the first compressed air pipe is connected with the inner pipe to mix liquid and gas. The nozzle at the end part of the inner pipe is adjustable in angle and can spray and combust according to angle requirements; and the second compressed air pipe is connected with the out