Combustion furnace and assembly

A combustion assembly comprising:

• a non-metallic refractory block, said block:
• extending over a height h between a lower end and an upper end,
• having an inlet face and an outlet face opposite the inlet face, the outlet face and the inlet face being spaced apart by a thickness ep,
• the block being divided over height h into several levels, each level containing at least one passage for injecting fuel and/or oxidizer, each passage extending from the inlet face to the outlet face and terminating in at least one injection aperture in the outlet face of the block, the at least one injection aperture of each level defining, on the outlet face, a contact rectangle, two segments of which are parallel to the direction of the height h and two segments of which are perpendicular to the direction of the height h, each injection aperture of the corresponding level being located entirely inside said contact rectangle and each segment of the contact rectangle being in contact with the contour of at least one of the at least one injection apertures of the corresponding level,
• several burners with one burner per level, each burner having injectors, including:
• at least one injector for injecting a fuel fluidically connected to a fuel inlet of the burner;
• and
• at least one injector for injecting an oxidizer fluidically connected to an oxidizer inlet of the burner,
• each burner being mounted on the corresponding level of the block such that the fuel and oxidizer injectors of the burner are inserted into the at least one passage of said corresponding level and such that the fuel and oxidizer inlets of the burner are located on the inlet face of the block,
• each burner is able to generate a flame by combustion of the fuel with the oxidizer downstream of the outlet face of the block, the length of which may be varied at constant flame power,
• the at least one passage of the various levels are oriented and spaced apart such that when the burners generate a flame downstream of the outlet face of the block by combustion of the fuel with the oxidizer, the flames generated by the various burners are spaced apart from one another and non-convergent, and
• the contact rectangle defined on the outlet face in the level contiguous with the lower end of the block has segments perpendicular to the direction of the height h, the length x of which is at least twice the length y of the segments parallel to the direction of the height h.