Device for improving thermal efficiency of garbage incinerator

A device for improving thermal efficiency of a garbage incinerator relates to the technical field of waste heat boilers. Comprising a waste heat boiler shell, the waste heat boiler shell is sequentially provided with a first return stroke chamber, a second return stroke chamber and a third return stroke chamber which are vertically arranged from left to right, a fourth return stroke chamber which is horizontally arranged is arranged on the upper portion of the right side of the third return stroke chamber, and the second return stroke chamber and the third return stroke chamber are separated through a membrane type water cooling wall; the third return stroke chamber is communicated with the fourth return stroke chamber; the second return stroke chamber and the third return stroke chamber are each internally provided with a heat exchange coil pipe. According to the utility model, a group of flag-type heating surface components (serpentine pipes) are respectively added in the second return stroke and the third