The boiler of 6-35t/h is composed of 2 main components. The upper assembled component is the body heat accepting part, and the lower assembled component is the combustion equipment. The former part of the boiler body is arranged with a water cooling wall, the upper part of it is connected to boiler cylinder, and its lower part is connected to collective chest, so as to form a combustion room and absorb the radiated heat from the furnace.