Dryer Cylinder

The dryer section of the paper machine, as its name suggests, dries the paper by way of a series of internally steam-heated cylinders that evaporate the moisture. Steam pressures may range up to 160 psig. Steam enters the end of the dryer head (cylinder cap) through a steam joint and condensate exits through a siphon that goes from the internal shell to a centre pipe. From the centre pipe the condensate exits through a joint on the dryer head. Wide machines require multiple siphons. In fast machines centrifugal force holds the condensate layer still against the shell and turbulence generating bars are typically used to agitate the condensate layer and improve heat transfer.

Paper Machine Dryer Cylinder heads and journals are made of special cast iron. Separate journals are bolted onto the dryer heads, Dryer shells are ground on the outside and turned on the inside, while all dryer journals with steam or condensate pipes have insulation sleeves. The inner surface have grooves for the stationary siphones, the front side ends of all dryers contain manholes.

The main parts of dryer cylinder include: shell, dryer bars, syphon, manhole cover, shell head, spherical roller bearing, steam joint, etc.