Brief introduction of polyester dryer fabric

The primary function of a polyester dryer fabric is to keep the sheet in contact with the dryer cylinders to provide maximum heat transfer from the cylinder to the sheet. The water on the surface will heat up if a wet object is placed against a heat source,. In the case of paper, the evaporation of the heated water creates a positive pressure that tends to lift the sheet off the dryer. This reduction of contact with the dryer will result in poor heat transfer and poor drying efficiency.
A layer of air between the sheet and the dryer also is carried by the moving sheet and dryer cylinder. The polyester dryer fabric presses the sheet onto the dryer, reducing this air layer. Additionally, because of the high machine speeds being run today,the fabric minimizes the effect of centrifugal force, which wants to lift the sheet. 
The polyester dryer fabric also functions as a drive belt to turn the majority of the rolls and dryers in recent machines, because only a few of the dryers are driven by the machine’s motors.
Polyester dryer fabrics perform all the preceding functions in a very hot and wet environment.The fabric surface and seams must be smooth to ensure the fabric does not cause deterioration of the paper surface.For many applications, the sheet leaving the dryer section is not sufficiently smooth. A calender is used to compress the shteet to give it the smooth surface required for high speed.