Steam and superheated water boilers, firetube (shell) design

Our firetube boilers, for steam and superheated water production, deisgned, manufactured and tested according to the European Directive 2014/68/EU, have been designed both for “heavy-duty” uses and for energy saving thanks to the most up-to-date technological solutions together with the most advanced manufacturing systems.

Three-pass boilers

• Three passes to enable the maximum exploitation of heat thus reaching high efficiency.

Wet back

• With reversal chamber totally immersed in water to widen the surface directly exposed to the flame,
• No refractory material to cut off maintenance costs, the loss of heat through radiation and the overheating of the rear tube plate.

Big water content

• The boiler has a big water content and (for steam boilers) a wide evaporating surface, granting a high thermal volume and the best steam quality.

Strong water circulation

• The downwards firetube eccentricity, the symmetrical placing of the tube nest and the absence of any obstacle enable the intense circulation of water inside the boiler avoiding local overheating.


• With big diameter, to enhance the heat exchange, the steam output and the efficiency, always observing the most severe environmental standards for flue exhausts,
• Downward eccentric firetube to obtain the maximum circulation of water inside the boiler and the steam chamber to an extent capable of meeting unexpected requirements at best,
• Fox corrugated as a standard for boilers with ratings higher or equal to 10 t/h of steam or 7MW for superheated water, on request for lower ratings.

Tube plates

• With flanged ends to uniformly absorb the expansion of the main body and the tube nest, functioning as real compensators, avoiding the risks of “cracks” typical of fillet welded flat plates,
• Formed and subjected to thermal normalisation treatment,
• Mechanical preparation of the edges to avoid thermically altering the areas to be welded,
• With expansion grooves inside each opening corresponding to the smoke tubes, so that all the tubes perform the double function of stay rods and compensators,
• The rear tube plate and the rear plate of the smoke reversal chamber are constrained by stay rods obtained from full round ASTM A105 bars diam. 50 (PB series).

Expanded tubes

• In the PB series boilers, the tubes are all exclusively expanded (with the sole exception of the tubes of the second pass of the smoke reversal chamber, where they are both expanded and welded), using the above described grooves.

Accessibility and maintainability

• Trap-doors both in the front smoke chamber and the rear one for total and immediate accessibility to the smoke tubes and the tube plates (for cleaning, maintenance and ease of inspection on the part of the Authorities entrusted with periodic inspections),
• Absence of tubes in the lower part to facilitate cleaning of the water side,
• Large diameter cylindrical shell supplied with manhole, hand or man hole doors, intake pipes, couplings for auxiliary units and lifting eyebolts,

Possibility of operation without the continuous supervision of operators for 24-72 hours

• Fittings and components for control and safety to permit homologation for operation without the continuous supervision of operators for 24-72 hours, in accordance with the regulations in force at the site of installation.

Environment protection and low emissions values

• Thanks to the coupling of new-concept “Low NOx” burners with the large combustion chambers of MINGAZZINI boilers, it is possible to obtain NOx and CO values able to respect the most restrictive local and international regulations in force for emissions.
• Finally, providing exclusive energy recovery systems, MINGAZZINI is positioned as a leader in the supply of steam boilers, not only of high reliability, but also capable of maximizimg energy savings, always respecting the environment and the limits regarding CO emissions.

Remote control with complete supervision

• It is possibile to provide the boiler with a control panel designed to allow the complete remote supervision and management of the single boiler or of the whole boiler room, with the use of the most reliable electronic components for the highest operation safety.
• This system allows the most up-to-date remote control concept for a perfect remote diagnosis of the boiler system, with the possibility of analysis and resolution of problems by remote connection.
• The system can be implemented for the fully automatic cascade management of 2 or more boilers.

Energy recovery

• All MINGAZZINI steam boilers of PB and PVR series come with a standard efficiency of 90%.
• Depending on the number of working hours and the type of fuel used, we can supply standard energy recovery systems dedicated to the single generator, to achieve efficiencies up to 97.5%.
• Finally, there is the possibility of even higher results with exclusive energy recovery systems tailored to the customer, to achieve efficiencies up to 99%.