Composite smoke speed convection heating surface of oil and gas boiler

The utility model relates to convection heating surfaces of oil and gas boilers, in particular to a composite smoke speed convection heating surface of an oil and gas boiler. The technical problems that in an existing commonly-used oil and gas boiler constant smoke speed convection heating surface, when smoke speed is high, smoke passes through all levels of smoke return channels in the convection heating surface, and the vibration generated by impacts to the convection heating surface is enhanced level by level along with the level-by-level increase of the intensity of the smoke are solved. According to the technical scheme, the composite smoke speed convection heating surface of the oil and gas boiler is a convection pipe bundle area connected between an upper boiler barrel and a lower boiler barrel, a membrane type wall inner partition parallel to a water cooling wall separating the convection heating surface and a combustion chamber is arranged on the convection heating surface, the levels of return chann