Results for Fine Paper Machines
Paper chemistry is important in the Fine Paper grades so most machines run a lower headbox temperature than, for example, Linerboard machines. This improves the potential of steam application because a smaller increase in sheet temperature has a greater effect on water removal than for a high temperature application like Linerboard.
However, heating the sheet can sometimes upset the chemistry.
An obvious application is over an open suction couch (as long as it's clean of splatter).
Many Fine and Specialty Paper machines run a variety of grades and a steam injector application can be used for certain of them and not used for others.
Nip vs. Felt dewatering: the positioning of the Lazy Steam Injector on the press fabric can better control which of these occurs.
Several Fine Paper machines are using unique “edge Injectors” in suction press nips to dry up wet edges.
Care should always be taken when using steam in the vicinity of any natural granite roll.
Example of temperatures with and without steam over open suction couch of small Fine Paper machine. Note the lower sheet temperature coming off the Fourdrinier without steam. (Bold denotes sheet temperatures and parentheses denote with steam.) Most significant finding on this particular machine was the significantly higher sheet temperature (13 F) ahead of the Size Press with steam. The higher temperatures improved the water removal and enabled them to make the 100 lb Cover grade that they could not before. Unique custom "gutters" were used in this application to alleviate dripping caused by an unstable steam supply to the Lazy Steam Injector.
Excellent application of a Lazy Steam Injector of a Light Weight Coated machine to increase the machine speed 120 ft/min. This injector sucessfully replaced one of another design and manufacture that caused runability issues due to having to be mounted too close to the sheet. The Lazy Steam Injector allows up to 3" clearance and still give excellent performance. Several other paper machines in this mill are now using this same equipment. Red denotes significant temperature improvements. For a discussion on efficiency of this particular application see "Energy Efficiency of Steam Showers."