How to repair the dryer cylinder of the paper machine

Paper dryer cylinder refers to a machine used in papermaking machinery to continuously dry the paper blank after the pulp is formed. Dozens of drying cylinders are placed crosswise in a paper machine. The paper drying cylinder is a roller-type pressure vessel, with rotatable shafts on the heads at both ends, and the steam for drying paper is passed through the inner hole of the hollow shaft at one end. There is also a bucket containing water in the cylinder to send the condensed water into the hollow shaft at the other end for discharge. The drying cylinder is generally made of cast iron and polished on the outer surface. The paper blank and the cylinder surface can be easily separated from the surface of the cylinder by using the characteristics of multiple graphite flakes in the cast iron, so that the paper will not be stuck when the paper is dried.

The drying cylinder of the paper machine is commonly called the dryer cylinder. The drying cylinder is generally composed of a roller and a supporting shaft. The drying cylinder shaft is usually made of cast iron. In order to facilitate the maintenance of the bearing and the shaft, it can be divided into two categories: expansion fit and taper fit. There are many reasons for wear and tear, and if it is not handled in time, it will have a serious impact on paper products and equipment.

The dryer cylinder is a hollow cylinder made of cast iron with covers at both ends. It consists of a cylinder body and cylinder heads at both ends. The outer diameter is mostly 1000～3000mm. During operation, the conveyed paper will be dried by steaming inside. Burned. Dryer wear problems are very common in industrial equipment.

1. Causes and analysis of the abrasion of the dryer cylinder shaft of the paper machine

(1) The reason for the fit size is mainly caused by the error during machining.

(2) The reason for assembly depends on the assembly process and technical means.

(3) The reason for the use of the bearing is that the temperature of the bearing during use is too high, and it bears the axial force and the radial force at the same time, which leads to the interference size metal fatigue between the shaft and the bearing and the matching clearance. Once the matching clearance occurs, the bearing and the Relative movement between the shafts aggravates wear, and in severe cases, the bearing or dryer shaft is scrapped, causing a vicious event.

(4) Normal metal fatigue wear: The metal itself has certain fatigue characteristics. Long-term torque will lead to normal fatigue wear of the metal. This phenomenon is determined by the characteristics of the metal itself. Therefore, only the shaft production process can extend the metal fatigue by improving the production process. Cycle to increase service life;

(5) Lubricating oil quality problems: lubricating oils generally used are divided into synthetic oils and petroleum-based lubricating oils. Lubricating oil has a certain degree of anti-wear, pressure resistance and viscosity-temperature properties. Therefore, inferior lubricating oil generally cannot adapt to the high temperature environment of the dryer operation during the use process, resulting in the rupture of the lubricating oil film or the inability to form an effective lubricating oil film, resulting in poor bearing lubrication. Therefore, the friction coefficient during the operation of the bearing is large, which causes a large torque force to be formed between the inner ring and the shaft surface, causing damage to the bearing and subsequent shaft wear;

(6) Improper maintenance: Failure to replace the bearings in time or poor lubrication is also one of the main reasons for the wear of the dryer cylinder shaft;

(7) Withdrawal sleeves, adapter sleeves or tightening nuts are loose, resulting in gaps in the mating surfaces, resulting in shaft wear.