Multistage flow-equalizing tempering-preventive front-mounted device of porous medium burner

The utility model relates to the field of gas burning of industrial furnaces, particularly relates to a tempering-preventive component of a porous medium burner, and provides a multistage flow-equalizing tempering-preventive front-mounted device of a porous medium burner, which comprises a gas pipe, an air pipe and a pre-mixing channel. The gas pipe and the air pipe are communicated with the pre-mixing channel, and the pre-mixing channel is a tapered and expanded type tubular channel and consists of a tapering section, a straight tube section and an expanding section. The gas pipe with cyclone ribs, a low-resistance folded plate flow equalizer and a grating flow distribution guide plate are mounted on the outer wall of the front-mounted device so as to realize forced mixing, flow equalization and flow distribution of air and gas together. The tapered and expanded tubular channel obviously resolves the problem that air and gas in an original burner are not mixed uniformly, leads air and gas to be mixed uniformly sufficiently, prevents tempering, improves safety, and can effectively reduce resistance loss of the porous medium burner, thereby reducing current consumption of a fan.