The Yankee Dryers, or MG cylinders, are used in the production of various types of MG paper, as well as of tissue.
In OVER we have supplied more than 200 of these dryers all over the world, for hard or creped tissue, MG paper, types of one-side coated paperboard and for folding cartons. Special alloys are used for the Yankee heads and shells; the typical material utilized is nodular cast iron GJS 400-15-UNI 1563, for heads and journals, and cast iron GJL 350-UNI 1561 for the shell with hardness 240 HB.
In the last years a new steel shell “Yankee type” for the tissue production has been developed, especially for those markets where gas is usually not used. In order to increase the heat exchange through the Yankee, a grooved shell of special steel is mounted on heads and journals, in nodular cast iron and cast iron type GJS 400-15. The steel shell is covered with a special hard metallization with a surface hardness of 550 HB.
Our OVERMADE Steel Shell Yankees, with their bolted heads construction, have shown excellent performances over the years, despite the thermal stress and deformations affecting the dryer cylinder during the drying process of the paper, and considering also the edge drying and creping issues.
Independently of the shell material, to increase the heat exchange, a special grooving of the inner surface can be carried out. Special stainless steel spoiler clips inserted in the grooves induce turbulence in the condensate layer, further enhancing the overall heat transfer. Besides that, there is a condensate removal device, with multiple headers provided with small stainless-steel tubes that suck the condensate out of each groove, like a soda straw.
Our Manufacturing Capability in OVERMADE includes:
- operating pressure of 5 or 8.5 and 10 bar,
- plain or ribbed inner surface,
- pressure vessel coding available for all countries.
The diameter of the OVERMADE Yankees ranges from 3200 mm up to 4877 mm without face length limitations and all are equipped with accessories, such as steam and condensate rotary joints and a specially-built, double-reduction, hollow shaft gear box. This gear box is lubricated by a dedicated forced oil lubrication unit, which also supplies the Yankee bearing housings.
Our team is ready to assist you from the design phase to the complete turn-key service. Ask more information.