Common Dryer Cylinder Problems and Solutions for Paper Mill
The dryer cylinder is a key part of the paper making machine. It uses steam heat to dry the paper web. It removes water and gives the paper strength. A good dryer cylinder helps you make smooth, dry paper. But dryer cylinders can have problems.
Problem 1: Bearing Failure
Bearing failure is a common problem. It happens for several reasons. Oil contamination is the top cause. Water and dirt get into the oil and make it break down. Poor installation and wrong bearing clearance also cause problems. When the bearing fails, the journal can wear down. Metal particles from the worn journal get into the oil and can damage other parts.
Solution: Use good quality bearings. Install them correctly. Check the oil regularly for water and dirt. If the oil is dirty, change it right away. For our Φ3660 dryer cylinder, we use Wafangdian bearings. The bearing housing is cast steel. The journal has a 1:12 taper. The bearings use oil lubrication. We also recommend checking vibration and temperature often to catch problems early.
Problem 2: Condensate Accumulation
Condensate is water that forms when steam cools inside the cylinder. If the condensate is not removed, it collects at the bottom of the cylinder. This water layer reduces heat transfer. It causes uneven paper dryness and can lead to sheet breaks. The siphon system is supposed to remove this water. If the siphon is blocked or damaged, water stays inside.
Solution: Use a good siphon system. For our Φ3660 dryer cylinder, we use a bucket type siphon. The drain plug is M20. We also recommend cleaning the siphon regularly. Check the gap between the siphon mouth and the cylinder wall. It should be about 2 mm. If you have a high-speed machine, consider adding spoiler bars to help break up the water ring.
Problem 3: Surface Wear and Corrosion
The cylinder surface can wear out over time. It can also corrode. Corrosion happens because of water and chemicals in the paper stock. Wear happens from the doctor blade and from paper running against the surface. When the surface is rough, paper quality drops.
Solution: Choose a cylinder with a hard surface. Our Φ3660 dryer cylinder has a surface hardness of at least HB255. The hardness difference across the surface is less than HB24. The surface roughness is not less than Ra=0.2m. We also recommend regular surface inspection. If the surface is damaged, it can be repaired with grinding or thermal spray coating.
Our Φ3660 dryer cylinder is made for printing paper lines. It has a diameter of Φ3660 mm and a face width of 5300 mm. The design speed is 350 m/min. The machine is right-hand type and rotates clockwise. The cylinder body is made of special alloy steel. The wall thickness is 50 mm. The maximum working pressure is 0.5 MPa. The water test pressure is 1.0 MPa. The steam temperature is 158°C. The surface hardness is at least HB255. The head bolts are 8.8 grade 40Cr special bolts. The manufacturing follows QB2551-2008. The design follows QB/T2556-2008. We use Wafangdian bearings. The bearings use oil lubrication. The drive side has a main gearbox with a closed pinion drive.
We offer this dryer cylinder and other paper mill equipment. We supply complete paper production lines. We also provide turnkey paper production line services. If you need a reliable dryer cylinder for your paper making machine, we can help.
Email: leizhanworld@gmail.com
