The melting of glass is inseparable from fire, and its melting requires high temperature. Coal, producer gas, and city gas are not used in the early days. Heavy, petroleum coke, natural gas, etc., as well as modern pure oxygen combustion, are all burned in the kiln to generate flames. High temperature melts glass. In order to maintain this flame temperature, the furnace operator must regularly observe the flame in the furnace. Observe the color, brightness and length of the flame and the distribution of hot spots. It is an important work that stokers usually operate.
In ancient times, the glass kiln was open, and people watched the flame directly with the naked eye.
one. The use and improvement of fire viewing hole
With the development of glass furnaces, pool furnaces have appeared, and the melting pools are basically completely sealed. People open an observation hole (Peephole) on the furnace wall. This hole is also open. People use fire viewing glasses (goggles) to observe the flame situation in the kiln. This method has continued to this day. It is the most commonly used flame. observation method.
Stokers use a sight glass to watch the flames in the hearth. Fire viewing mirror is a kind of professional fire viewing glass, which can be used to observe the flame of various glass furnaces, and is the most widely used in glass industrial furnaces. This kind of fire viewing mirror can effectively block strong light and absorb infrared and ultraviolet radiation. At present, operators are accustomed to using this kind of sight glass to observe the flame. The observed temperature is between 800 and 2000°C. It can do:
1. It can effectively block the strong infrared radiation in the furnace that is harmful to human eyes, and block the ultraviolet rays with a wavelength of 313nm that are most likely to cause electro-optic ophthalmia, which can effectively protect the eyes;
2. See the fire clearly, especially the condition of the furnace wall and refractory material inside the kiln, and the level is clear;
3. Easy to carry and low price.
two. Observation port with cover that can be opened or closed
Since the fireman observes the flame intermittently, the open flame observation hole in the above picture will cause energy waste and thermal pollution to the surrounding environment. With the development of technology, technicians have designed an openable and closed flame observation hole with a cover.
It is made of heat-resistant metal material. When the stoker needs to observe the flame in the furnace, it is opened (Fig. 2, right). When not in use, the observation hole can be covered with a cover to avoid energy waste and pollution caused by flames escaping. environment (Fig. 2 left). There are three ways to open the cover: one is to open left and right, the other is to open up and down, and the third is to open up and down. The three types of cover opening forms have their own characteristics, which can be used for reference by peers when selecting models.
three. How to distribute the observation hole points and how many?
How many holes should be opened for the fire viewing holes of the glass furnace, and where should they be located? Due to the large difference in size of glass furnaces and different working conditions of different fuels used, there is no unified standard. The left side of Figure 3 shows the number and location of openings in a medium-sized horseshoe-shaped glass kiln. At the same time, the location of the hole points should have a certain angle according to the situation, so that the key positions in the furnace can be observed.
Among them, the observation points A, B, E, and F are angled. Points A and B mainly observe the situation of the spray gun mouth, feeding port, small furnace mouth and rear bridge wall, while observation points E and F mainly observe the flow The condition of the front bridge wall in the upper part of the liquid hole. See Figure 3 on the right:
C and D observation points are generally to observe the bubbling situation or the working conditions of the rough surface of the glass liquid and the mirror surface. E and F are the situation of observing the flame distribution of the whole pool furnace. Of course, each factory can also choose the flame observation holes in different parts according to the specific conditions of the kiln.
The brick of the observation hole is dedicated, it is a whole brick (Peephope Block), and its material is generally A.Z.S or other matching materials. Its opening is characterized by a small outer aperture and a large inner aperture, and the inner aperture is about 2.7 times that of the outer aperture. For example, an observation hole with an outer aperture of 75 mm has an inner aperture of about 203 mm. In this way, the stoker will observe a wider field of vision from the outside of the furnace to the inside of the furnace.
Four. What can I see through the viewing hole?
By observing the furnace, we can observe: the color of the flame, the length of the flame, the brightness, the stiffness, the condition of burning (with or without black smoke), the distance between the flame and the stockpile, the distance between the flame and the parapet on both sides (whether the parapet is washed or not), The condition of the flame and the top of the furnace (whether it is swept to the top of the furnace), the feeding and feeding, and the distribution of the stockpile, the bubble diameter and frequency of bubbling, the cutting of the fuel after the exchange, whether the flame is deviated, and the corrosion of the pool wall , Whether the parapet is loose and inclined, whether the spray gun brick is coked, etc. Despite the development of modern technology, it should be noted that the flame conditions of no kiln are exactly the same. The kiln workers must go to the scene to watch the flame before making a judgment based on “seeing is believing”.
Observing the flame in the kiln is one of the key parameters. The domestic and foreign counterparts have summed up the experience, and the temperature value (COLOR SCALE FOR TEMPERATURES) according to the color of the flame is as follows:
Lowest Visible Red: 475℃,
Lowest Visible Red to Dark Red: 475～650℃,
Dark red to Cherry Red (Dark Red to Cherry Red: 650～750℃,
Cherry Red to Bright Cherry Red: 750～825℃,
Bright Cherry Red to Orange: 825～900℃,
Orange to yellow (Orange to Yellow0: 900～1090℃,
Yellow to Light Yellow: 1090～1320 ℃,
Light Yellow to White: 1320～1540℃,
White to Dazzling White: 1540°C, or over (and over).
The above data values are for reference only by peers.
Figure 4 Fully sealed viewing port
It can not only observe the combustion of the flame at any time, but also ensure that the flame in the furnace will not escape, and it also has various colors for selection. Of course, its supporting devices are also quite complicated. From Figure 4, we can vaguely discern that there are many devices such as cooling pipes.
2. Observation hole openings tend to be large in size
These are two recent photos of on-site fire viewing. It can be seen from the pictures that the commonly used fire viewing mirrors only occupy a small part of the portable fire baffle, and this photo shows that the kiln viewing holes are relatively large. The inference observation hole has a tendency to expand?
Such an observation field must be broad, and due to the use of a cover, it will not cause the flame to escape when the cover is usually closed.
But I don’t know what strengthening measures have been taken on the furnace wall structure (such as adding small beams on the top of the observation hole, etc.). We need to pay attention to the trend of changing the size of the observation hole
The above is only the association after viewing this photo, so it is only for reference by colleagues.
3. Observation hole for the end wall of the regenerator
In order to observe the combustion of the entire kiln, a factory has opened an observation hole on the end wall of the regenerator on the two sides of the horseshoe-shaped kiln, which can observe the combustion of the entire kiln.