China good quality boiler membrane water wall with favorable price is main radiation heat surface, arranged inside the boiler chamber and proceeds the heat exchange directly with the high temperature flame. The convection tubes are the convection heat surface of the boiler, arranged between the boiler chamber outlet and the end heat surface and proceed the heat exchange directly with the high temperature fume. The water wall and convection tubes are the main heat surface of the boiler, the tubes diameter for both Generally used Ï?51~60mm boiler streel tubes, also as the request. China good quality boiler membrane water walls with favorable price that are made of tubes welded together with or without a strip of metal in between. These walls form the enclosure of the coal combustion chamber. Membrane water wall are also referred to as the evaporator section; they contain water mostly in liquid form which gradually evaporates as it rises in the steam boiler.