Mingazzini‘s activity, based on continuous technological innovation and tradition, integrates the construction of plants as firetube steam boilers of the PB-EU series, with three pass, for a steam output of 6000 kg/h. The wet back totally immersed in water widens the surface directly exposed to the flame, and there is no refractory material causing the loss of heat through radiation and the overheating of the rear tube plate thus cutting maintenance costs. The boiler has a large water content and a wide evaporating surface providing for high thermal volume and best steam quality. The large diameter of the firetube enhances the heating exchange, the steam output and the efficiency, always observing the most severe environmental standards for flue exhausts. The tube plates with rounded edges uniformly absorb the expansion of main body and tube nest, acting as real compensators, preventing the risks of “breakage” typical of corner welded flat plates. The system, equipped with an air preheater or an economizer to increase thermal efficiency up to 96%, allows continuous unmanned operation.