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　　1. Silicon carbide roller replacement is best performed during kiln shutdown or at low temperatures (below 800 degrees Celsius) to ensure safety and prolong the lifespan of the replacement rollers. No more than two rollers should be broken in one location; otherwise, emergency replacement or immediate kiln shutdown is necessary.

　　2. In practice, due to various reasons, we may not be able to immediately cool down, shut down the kiln, or stop the firing process to replace the rollers. Instead, we replace the broken rollers while maintaining normal firing operations. In this situation, we should first take out a new roller (of the same model as the broken roller), insert refractory wool into one end, and install a spring on the other. Then, in the 400-500 degree Celsius zone, remove a roller and replace it with the new roller for preheating for 20-30 minutes (the end with refractory wool inserted into the drive side), or pre-install a high-temperature zone roller model in the 400-500 degree Celsius zone for replacement.

　　3. The length of refractory wool to be inserted into the new roller is L, which is the thickness of the kiln wall; the starting depth of the wool insertion is L+L1, which is the portion of the porcelain tube exposed outside the kiln wall plus the kiln wall thickness; the ending depth of the wool insertion is L1, which is the portion of the porcelain tube exposed outside the kiln wall. Initially, insert refractory wool only into the drive end of the new porcelain tube; the refractory wool on the other end should be inserted after installation. (As shown in the figure below)

　　4. Remove the broken silicon carbide roller and temporarily plug the brick hole with refractory wool to prevent heat loss and cold air entry; the porcelain tube on the drive side needs to have the drive gear removed before it can be removed, or it can be pushed into the kiln (note that the broken roller must fall below the roller horizontal plane and must not obstruct the movement of the kiln board). Clean it after kiln shutdown. Pay special attention to the process of removing the roller to prevent burns from rapid cooling and breakage of the roller.

　　5. Remove the preheated new roller, slowly insert the end with refractory wool inserted into the broken roller while rotating, ensuring the insertion speed is not too fast and continuously rotating.

　　6. When the roller is pulled out from the drive side kiln wall, do not rush to install the drive gear. First, simply fill the gap between the porcelain tubes with refractory wool and continue to rotate the porcelain tube continuously. After the porcelain tube head on the drive side cools to a certain temperature, install the drive gear and gently install the porcelain tube into the steel casing to prevent damage due to rapid cooling when the hot porcelain tube contacts the steel casing. Note that the drive gear must be installed correctly, horizontally, and the distance between the adjacent front and rear drive gears must be consistent.

　　7. After installing the new roller, fill the gap between the two ends of the roller and the kiln wall with refractory wool, ensuring it is tightly packed, especially the gap between the lower part of the porcelain tube and the kiln wall. Also, pack the end of the roller where refractory wool has not been inserted with wool. The depth of the wool insertion should refer to the requirements in point 3. Finally, check if the spring is on the bearing and use a marker pen to write the replacement date and time, porcelain tube model, and porcelain tube serial number on one end of the porcelain tube.

　　8. Record the date, time, roller model, quantity, fracture location, serial number of the broken roller, the previous replacement date and time of the broken roller, and the person in charge on duty in the "Broken Roller Special Record Book". Note: Detailed records are also required for consecutive breakage caused during the replacement of porcelain tubes.

　　9. Take out the broken roller for observation (roller model, fracture location, wear and tear, thickness, density, other abnormalities), analysis, and discussion, and report to the superior for effective control and improvement measures.