1948-2008: Toscotec celebrates 60 years of activity. Innovation as a trademark.
The history of the Paper Industry of Lucca is deeply related to the 60 years of activity of Toscotec. Founded in 1948 by Sergio Toschi to provide services for local paper mills with the name Officine Meccaniche Toschi, Toscotec’s activity has been always oriented towards the development of paper machine components, accessories and sections. In the 1950s and 60s, thanks to Giovan Battista Mennucci joining the Toschi family as shareholder, Toscotec started to design and manufacture the first complete paper machines and, in the following years, tissue machines.
In this period, Toscotec was the first company to manufacture steel drying cylinders for paper production providing substantial economical and operational benefits thanks to their higher drying capacity. In the 1970s Toscotec manufactured the first complete tissue machine. These are years of expansion, thanks to growth in export sales. In 1998 Toscotec, managed by the Mennucci family, experiences a new phase of technological and market growth together with Mr. Fabio Perini, the world famous entrepreneur that acquires the shares of the Toschi family. In 2003 Toscotec officially becomes the new brand of Officine Meccaniche Toschi: this is not merely a new name but the sign of a further radical process of company expansion and renewal.
Finally, at the beginning of 2006, the Mennucci family acquires the shares of Mr. Fabio Perini and, through their holding (Mennucci Group), has the complete control of the company. The following period, 2006-2008, confirms the validity of Toscotec’s strategic decisions: positive commercial results confirmed by a growing trend.
On the year of their 60th anniversary, Toscotec will organize, together with the Fondazione Giuseppe Lazzareschi, the third edition of “Tecnologia e Passione - Premio per l’Innovazione” awards, to be held in Porcari, near Lucca, on October 17, 2008.
Perini Journal
For a company producing paper machines and complete plants, to be 60 years old and in good shape means to be able to combine perfectly product reliability and technical innovation, quality of components and high performance of the whole plant.
These, together with the strong partnership with its customers aiming to find innovative solutions capable of satisfying their requirements, are the roots of Toscotec’s success.
Supplying standard equipment has never been Toscotec’s approach to the market. In their components and equipment, they have always introduced technical innovations designed to mark a step forward to reach the targeted performances.
The constant market demand for high quality finished products and for plants with high operating speed found in Toscotec a reliable and expert supplier.
In addition to “turn-key” supplies and brand new tissue machines, Toscotec is today a strategic player for developing process solutions to improve performances and optimize operating costs of existing plants thanks to the upgrading and rebuilding of machine sections and complete plants.
TT Steel Yankee Dryer: a success STORY. The highly competitive market for tissue production and the constant increase in energy costs are the driving forces for the development of new technical solutions and, since tissue drying is an intensive energy process, most tissue machine suppliers focus their efforts in this area.
In these last years, major innovations have involved pressing technology (shoe press) and air systems (high temperature hoods) but the heart of the tissue machine, the Yankee dryer, remained substantially unchanged throughout this period.
In the late 1990s, Toscotec started designing a totally new approach to the manufacturing of Yankee dryers. Thanks to the broad experience gained through the construction of steel dryers for the production of paper & board, the Toscotec technical team was able to develop solutions capable of guaranteeing stability and roundness all through the lifespan of a Yankee dryer.
The major concerns taken into consideration during the design phase where the quality of the outer surface in contact with the creping blade and the analysis of all the forces playing against the Yankee dyer such as internal pressure, nip pressure, temperature, etc.
Thanks to the development of high quality spray metal coating processes, it was possible to overcome any problems due to the relative softness of steel when compared to cast iron. At the same time, an in-depth study of the reactions of a steel shell to the various forces under operating conditions was carried out also thanks to Finite Element Analysis (FEM), which also gave positive results in view of the long lifetime of a Yankee dryer.
In 2000 the first TT-SYD (Steel Yankee Dryer) was installed in a tissue mill on the hills of Lucca. This unit, with a diameter of 2 meters, was extensively tested before taking the decision of finally marketing the TT-SYD. Since that time a total of 30 units have been sold, of which 17 already successfully started up (fig.1).
FIELD PERFORMANCES. During these 8 years in manufacturing and operating TT-SYDs, Toscotec has gathered a considerable quantity of field data showing the benefits of using steel instead of cast iron as material for Yankee dryers.
The main advantages of this technology are due to the higher mechanical properties of steel compared to cast iron, allowing to reduce the shell thickness by approximately 30% and consequently to increase the heat exchange of the system. As indicated in fig.2 (comparison between 15’ cast iron and TT-SYD), steel and cast iron have similar conductivity and therefore the 30% reduction in thickness translates in a 30% higher drying efficiency (fig.3).
Assuming that in a standard tissue machine there is an even split in drying action between Yankee and hood (50% each) the overall benefit of installing a TT-SYD translates into a 15% output increase.
But advantages do not end with higher drying capacity:
• elimination of all the problems arising from defective castings such as porosity, pin holes and non-uniformity of the shell material;
• higher flexibility of steel significantly reduces the risks of dramatic failures of the cylinder thus substantially increasing safety;
• thanks to the higher shell hardness due to the spray metal coating, which is supplied as a standard with the TT-SYD, there is a significant reduction in maintenance stops due to Yankee grinding;
• given the same face length of the dryer, the design of the TT-SYD with flat heads allows for a wider tissue sheet to be dried. This aspect is of great interest in case of replacement of an existing cast iron Yankee. Even using the same Yankee framing, it is possible to increase the net sheet width at the pope reel;
• no loss of efficiency due to reduction of operating pressure caused by grindings and consequent decrease of shell thickness.
SAFETY. During the design phase of the TT-SYD, great attention was placed on issues related to safety and the behaviour of the cylinder in long term operation. For this reason, Toscotec’s technical team analyzed the reaction of the TT-SYD models with FEM analysis in any operating condition. Great emphasis was placed on the response of the weldings and junctions of the TT-SYD in critical conditions.
Each TT-SYD is 100% tested with ultrasonic and magnetic controls for all the components as well as X-ray control on all the structural weldings. Of course, dimensional and pressure tests are performed before final approval of the cylinder.
But the most important benefit in terms of safety deriving from using a TT-SYD appears to be the behaviour of the cylinder in critical conditions that may lead to violent reactions in a cast iron Yankee. In this case, a TT-SYD will behave in a completely different way by losing its internal pressure without exploding, thus proving to be extremely safer.
CONCLUSIONS. Field measurement and direct experiences of mills running the TT-SYD yield extremely positive feedback. Calculations made solely on increased output (without considering the benefits of energy savings) gave a very short payback time; in some cases as short as one year.
It is important to highlight the fact that these improvements come without the downplay of having to change operator centerlines.
Apart from a slight change in the chemical package used for Yankee coating, which is recommended by Toscotec, the operator will continue to run the Yankee dryer in the same way as with a conventional cast iron unit.
On-site surveys gave clear indications of several improvements and benefits:
• higher evaporation rate resulting in a 30% increased capacity for the Yankee dryer;
• energy savings with lower steam consumption and less power required for the drive;
• reduction of chemical products for Yankee coating;
• better performance on the edges;
• complete elimination of problems due to porosity and pin holes; no problem regarding non-uniformity of drying across the Yankee face length;
• Increased blade life with consequent improvement of mill efficiency.
Toscotec is currently producing TT-SYD in diameters up to 16’ (4,876 mm) and net width of 5,700mm.
The success of this technology is clearly indicated in the progression in sales from Toscotec and in the fact that all tissue producers that installed their first TT-SYD have never gone back to the conventional cast iron units.