Water-cooled wall are boiler's radiation heating surface. It was arranged in the furnace. It carries on the radiation heat transfer directly with the high temperature flame. The convection bank is boiler's counter-flow heating surface. It arranges in the furnace outlet t and the rear part heating surface. It carries on the heat convection directly with the high temperature haze. Water-cooled wall and the convection bank are water-tube boiler's main heating surfaces. Boiler's water-cooled wall and the convection bank use generally ??51~??60mm. This products may also to be designed according to the user's demand.