The vast majority of the furnace body of the heating furnace is made of refractory bricks or refractory concrete masonry, which is generally built at low temperature and works at high temperature, therefore, after the completion of the newly built or large, medium and minor repair furnace, its refractory masonry contains a large amount of water and moisture, and cannot directly enter the high temperature state to work. Drying and drying must be done carefully so that moisture and moisture in the masonry can escape gradually, otherwise, the masonry will be damaged by violent expansion.
1.Drying and curing of furnaces.
The furnace must be dried before drying, and all furnace doors and flue gates should be opened during drying, so that the air can better circulate in the furnace and speed up the drying speed. The drying time of the furnace depends on the season of repair, the size of the furnace, and the drying condition of the masonry. Generally 24-48h or longer.
When the time between the completion of the furnace and the start of the oven is long, the masonry is already drying, and this time is actually the drying period of the furnace.
When the furnace is overhauled, often due to the high temperature in the furnace, the moisture in the masonry body will evaporate quickly during the furnace repair process, so there is no need for a special drying process in this case. For furnaces constructed with refractory concrete, they must be cured according to the maintenance system after tamping and forming on site.
2.Preparation before baking.
Before the oven is baked, all parts of the furnace must be carefully inspected, and the construction defects must be corrected, and the fire can only be ignited after it is confirmed to be qualified and cleaned. Therefore, the following preparations must be made before the oven is ignited:
2.1. Remove broken bricks, remove building materials and all arches.
2.2. Check the correctness of the masonry, the size of the masonry joints and the filling of the mud. These works should be carried out during the bricklaying process; Check whether the expansion joints of each part of the masonry of the furnace meet the requirements, because the furnace is often seriously damaged due to the unsuitable expansion joints during the oven drying process; Check the arrangement of brick joints, no through joints are allowed, special attention should be paid to the staggered joints and thickness of brick joints, check the levelness of each layer and the verticality of the furnace wall.
2.3. Test and test of mechanical equipment should be carried out to ensure that the operation is correct. The blower is running normally, and water, electricity, and steam must be connected. The instrument is in normal operation and the testing instruments, tools and records of the oven are complete.
2.4. Check whether the gas or oil pipelines, air pipelines, cooling water pipelines and steam pipelines are smooth and tight, and all pipelines must be tested under 2-3 times the use pressure to ensure safe production. Notify the vaporization cooling system (including the waste heat boiler) to release water before starting the oven, so that all the furnace ribs and water-cooled components are fed with cooling water. Gas and air pipeline openers, blind plates, shut-off valves, regulators, burner discharge pipes, water seals, steam pipes, etc. should be complete and meet the requirements.
2.5. Check whether all furnace doors are opened and closed flexibly, whether they are closed tightly, and each manhole and peephole are covered and tightly covered.
2.6. Check whether the burner is correctly opposite to the burner brick, the burner head should be in the appropriate position, and the burner adjustment mechanism should be flexible.
2.7. Check whether the furnace measuring instrument is complete, whether the instrument is running normally, and whether the oven tools and records are complete.
2.8. Check whether the welding of the slideway at the bottom of the furnace is firm, whether the expansion gap meets the requirements, whether there is the possibility of steel jamming along the direction of pushing the steel, whether the slideway is level, whether the loading and discharging port is smooth, and whether the insulation and wrapping of the water pipe at the bottom of the furnace is complete and meets the requirements.
2.9. In order to prevent the warping or deformation of the furnace rib tube and slide rail in the process of baking, the continuous furnace should be loaded into the scrap billet pressing furnace when the furnace temperature does not exceed 100, and the blank should be filled along the length of the furnace rib tube of the whole furnace according to the specific situation.
2.10. Check the flexibility of the furnace door and flue gate, and the gap between the gate plate and the frame should meet the regulations. There should be no serious water seepage in the flue. If the chimney and flue are new or cold, then the chimney and flue should be dried before the oven, the easiest way is to bake with firewood, and the temperature of the chimney is burned to 200-300, then the chimney has a certain suction force.
2.11. Safety protection equipment and measures should be complete to ensure safe production.