This method is a most attractive expansion option as it does not require any extension of the machine length. A 16 foot (5m) long fourdrinier can be located above an existing 40 foot (12m) fourdrinier to expand production capacity by 40%!

Hogenkamp introduced the first 4-Ply headbox back in 1971! More common are two or three ply headboxes. The Gap Formers are very compact in comparison with standard fourdriniers and this space saving allows you to expand your press section and reduce drying costs.

This  method has some advantage over the multi-layer headbox in that inter-ply fiber mixing is kept to a minimum. Installation is simpler becasue there is no existing equipment to remove. Also the secondary headbox can be equipped with automatic dilution profiling.