Each glass melting furnace is designed by the furnace designer according to the manufacturer's requirements according to the specified furnace period. After the furnace is put into production, the initial requirements may change due to factors such as productivity, market share, market environment, and competition.
These changes have a significant impact on the firing rate (output) of the furnace, which in turn will have an important impact on the internal wear of the refractory structure of the furnace and the design period of the furnace. If the feed rate can be maintained at a constant level with little or no large fluctuations, the internal wear of the refractory material structure will be reduced, and the damage rate will be relatively stable.
When the discharge rate frequently fluctuates regularly, the internal abrasion of the refractory structure above and below the glass liquid will increase. This increased internal wear of refractory materials may cause excessive wear, which may make the refractory structure inoperable due to damage.
The above factors, combined with the increase in the design period of the kiln and the increase in the discharge tonnage during the operation of the furnace, usually lead to an increase in maintenance requirements, as shown in Figure 1.
Figure 1. The relationship between increasing maintenance requirements and kiln period and glass output
[Type of inspection of refractory structure]
It is generally used at the same time or interactively within a few days for visual inspection or temperature self-recording inspection.
Based on the results of each inspection, accurate and reliable conclusions can be drawn about the current situation of the internal and external refractory structure, so that the correct maintenance method can be used to solve a problem.
The internal surface inspection can be used to obtain better images about the internal refractory structure or the condition of a selected part that cannot be visually inspected. This kind of inspection can also be recorded or photographed, which can be used as a useful reference at the time, directly or in the future, and can also be used for real-time discussions on the required maintenance project plan.
[Appearance inspection of refractory structure]
This is perhaps the most common and effective inspection method for furnace refractories. However, it should be noted that other inspection methods by providing actual relevant data, in maintenance, may also play an important role in extending the furnace design kiln period.
The visual inspection can be performed by experienced external personnel or trained internal personnel. The most likely person to perform this task is the kiln operator. Any personnel assigned to perform this inspection must either have experience or be trained in refractory materials, refractory structure design and masonry.
The internal training should be guided by people who have experience in the external inspection of the refractory structure of the glass melting furnace and have the required knowledge. This is very important. With such experience and knowledge, the current situation of refractory structure can be correctly assessed, and corresponding corrective measures can be proposed for the observed problems.
Inspections are usually carried out during the day. However, for best results, the same inspection should also be carried out at night when the lights are turned off. The lights-out inspection can help identify “hot” areas and areas where problems may occur in the future, especially those under the glass surface that are difficult to observe during the day.
This is especially true for the bottom of the kiln, the liquid hole, the refractory materials in contact with the molten glass, and the well-known weak parts of the melting furnace. Figure 2 Mark
the main weak points of the glass melting furnace-the relative size of each part reflects the recorded failure rate.
Both daytime inspections and nighttime lights-off inspections can determine early signs of damage that may appear prematurely, so that corrective measures can be proposed.
[Inspection plan]
Before carrying out the visual inspection of the refractory structure of the furnace, the inspection plan and report format should be implemented. Throughout the expected kiln period of the furnace, it is necessary to insist on operating and reporting as planned.
It is recommended that the appearance inspection plan be implemented approximately one month after the glass is put into production to ensure that a reference point is obtained as a reference for future inspections. Figure 3 shows the visual inspection plan for a new furnace with a design kiln period of at least eight years.
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Figure 2 . Pie chart of the relative importance of furnace "weaknesses"
Figure 3. Schematic diagram of the inspection plan for a design kiln period of more than 8 years
[Inspection report ]
Report on each inspection. The report should be in a standard format for easy reference, and the data and structure conditions recorded before and after the inspection can be compared. The report should be in the following format:
· Furnace area-melting furnace top, bottom, breast wall, shaped end wall, feeding end wall, flow hole, distributor structure, regenerator structure, feeding channel, etc.
·Observation—during the visual inspection, the condition of each refractory structure is recorded.
·Measures-propose measures to be taken to solve locked problems.
The report should also ensure that the recommended measures can be taken at the right time so that the best results can be achieved at the least cost. It can also be used as archive data, as a means to help design new furnaces.
The content of the report should include the results of observations on the specific refractory structure of the furnace. For each observation recorded, correction points should be given. The degree of correction depends on the severity of the observed refractory wear.
Next, when construction is needed, the maintenance project plan is determined according to the correction points.
[In conclusion ]
When the appearance inspection of the refractory material of the melting furnace is carried out by an experienced person with knowledge of refractory materials, refractory material structure design and masonry, the inspection will be useful for facilitating the execution of the refractory material structure maintenance plan and extending the kiln period.
As a result of reduced maintenance requirements, the maintenance costs of all refractory structures throughout the entire kiln period have been reduced. Early identification of problematic parts and possible problematic parts can prevent accidental and serious adverse situations in the refractory structure of the furnace.
In order to make the standards consistent during the entire inspection plan, it is recommended that the personnel responsible for inspection and preparation of the report organize and supervise the work required to complete the specified correction points. This ensures that the maintenance and work quality always meet the best standards, and the entire The possibility of failure of the refractory structure is minimized.
The main purpose of the furnace refractory appearance inspection and maintenance project plan is to extend the furnace design period, which can generally be extended by 12 to 18 months. At the same time, it can also help glass manufacturers organize furnace maintenance and transformation, and enable them to better adapt to market changes, product allocation, financial conditions and future development plans.
