Over 100 years since it was invented, the Yankee dryer is the heart of tissue mills around the world. But while the essence of the Yankee remains the same, today’s dryers differ greatly from those of a century ago, with technical developments that have improved reliability, efficiency and performance. These modern advancements also mean that tissue producers have more options to choose from than ever before.
When selecting a Yankee dryer, one important decision that most mills will face is the choice between steel and cast iron. Here, it’s important to focus on process compatibility, risk minimization, maximum output and utilization. No single solution can offer the best fit for all mills, and it’s therefore important to consider your production processes, the type of tissue product in question and the needs of your end-customers.
Furthermore, while cast iron Yankee dryers have a history of more than 120 years of service in the tissue industry, steel technology has been around for scarcely two decades. Working with a supplier that has ample experience with and a complete range of both varieties can therefore also play a critical role in making sure you get the best solution for your production.
There are a wide range of characteristics to consider when choosing a Yankee dryer, from energy savings and efficiency to safety and durability. In certain areas, steel can offer advantages over cast iron.
Most notably, steel is a stronger material. This means that the dryer design can have a thinner, more thermally efficient shell and greater drying capacity. You can utilize the added capacity, in turn, to shift drying from the hood, creating potential for reduced energy consumption. Steel is also a ductile material and generally better suited to pressure vessels, which offers safety benefits.
But this is only half the story. While steel can provide the best choice for some tissue producers, cast iron also presents a number of clear advantages.
Cast iron can be especially beneficial when it comes to characteristics that deal with durability. The material’s free graphite ensures a high level of resistance to corrosion and erosion, and cast iron also provides greater vibration damping properties than steel. When thinking long-term, consider that cast iron has demonstrated reliability in Yankee dryers throughout their century-plus history. There is far less data available on their long-term performance of newer steel Yankee technology.
Still not sure? Take a look at this table for an overview of how steel and cast iron Yankees compare when it comes to different properties and characteristics. Which factor is most important in your production?
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More info about Steel and casted Yankee dryers
Industry level: Introductory
Est. read time: 3 minutes
Summary: This article compares steel and cast iron materials for Yankee dryers and explains what tissue mills should think about when choosing between the two.