Double-medium cooling spray gun device capable of being replaced online

The utility model provides a double-medium on-line replaceable cooling spray gun device which comprises a piston pipe, one end of the piston pipe is connected with a water injection opening, the other end of the piston pipe is sequentially and fixedly connected with a transition connecting pipe, a ball valve and a spray gun base, a water injection pipe is arranged in the piston pipe, and a first piston with a water passing hole is installed at the end, close to the water injection opening, of the water injection pipe. One end of the air pipe is connected with the aerial fog nozzle, the other end of the air pipe is provided with an air passing hole, the outer side of the air pipe is sleeved with a second piston, an air chamber is formed between the first piston and the second piston, the air passing hole is located in the air chamber, the side wall of the piston pipe is further provided with a small ball valve and an air injection port, and the air injection port is located in the air chamber. The small ball v