JPS646394B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a device that is a further improvement of a roller hearth kiln, which is a relatively new type of continuous kiln among various ceramic kilns, and is a device for producing tangible ceramic products. This invention relates to a new roller hearth kiln which is a continuous large-scale firing method and is capable of extremely uniform heating and firing in order to almost completely eliminate deformation due to heating that is often seen in conventional furnaces.

[Prior Art] Ceramics manufacturing furnaces generally include a melting furnace and a firing furnace.The firing furnace includes a furnace for firing amorphous materials such as cement clinker and dolomite clinker, and a furnace for firing tangible materials such as ceramics and bricks. The latter includes single kilns and continuous firing furnaces.

Individual kilns are preferred for high-quality ceramics, but continuous kilns are used for general ceramics, bricks, etc. as they are suitable for mass production. Climbing kilns and tunnel kilns have long existed as continuous kilns for firing general tangible ceramics, but both have low thermal efficiency and have many inconveniences such as the use of trolleys, so recently roller kilns have been used. Hearth Kiln has appeared.

A roller hearth kiln is the above-mentioned continuous firing furnace, in which a large number of refractory rollers forcibly rotated by power are arranged horizontally in the approximate center of the furnace body and placed on a roller hearth. The object to be heated is fired while being transferred by the rotation of rollers, and is widely used for ceramic overlays, tile firing, etc. The transfer roller of this conventional roller hearth kiln has one end that is directly connected and fixed to a drive device, and the other end that can slide in the axial direction of the roller during thermal expansion. The burner is attached to the side wall of the furnace, and the flame is injected from the furnace wall toward the center of the furnace.

[Objective of the present invention: Problems to be solved] The conventional roller hearth kiln is of the form described above, but FIG. 6 shows a cross-sectional view of a specific example thereof, and it has the following problems. There are various drawbacks.

FIG. 6 is a cross-sectional view of the transfer roller part. The upper furnace body 1 and the lower furnace body 2 appear to be separated at the roller part, but in conventional roller hearth kilns, the upper and lower parts are one piece. , it is only divided in the furnace length direction. Therefore, it is difficult to structurally absorb thermal distortion caused by expansion and contraction between room temperature and heating, and as a result, breakdowns are more likely to occur, rapid heating is not possible, and it takes a long time to repair breakdowns, which slows down production. The problem is that efficiency is low.

The conventionally used transfer roller 3 is a round bar, one end of which is directly connected and restrained to a drive device 30.
The other end is simply supported and rotates to transport the object to be fired 12 in the advancing direction. However, this is because one end is restrained, and because the conventional burner 31 is installed on the side wall and the flame is injected toward the center, the middle part of the transfer roller 3 is likely to be overheated, and during firing operation There are often things that cause deformation.

Therefore, if these are rotated while being deformed, it is often impossible to correctly transfer the object to be fired from the inlet to the outlet. Therefore, there is a problem in that the objects to be fired may stick to each other or overlap if they are plate-shaped objects, resulting in uneven firing and a tendency to malfunction.

In addition, because the flame of the conventional burner 31 is injected toward the center of the furnace, the temperature distribution within the furnace is not uniform, and there are parts where the temperature is excessively high, especially near the center of the furnace. Therefore, a portion of the object to be heated may melt and adhere to the roller 3. In addition, accidents such as the objects to be heated 5 being welded together are likely to occur, so the roller surface must be cleaned and replaced, and the furnace is frequently shut down and repaired, resulting in poor thermal efficiency and poor production efficiency. It also has

In particular, in the case of a furnace with a wide structure, it is difficult to reduce the temperature difference between the central part and the part near the side wall because the heating method uses a burner that injects flame from the side wall as in the conventional method. As a result, the heating of the object to be heated becomes non-uniform, which not only makes it impossible to obtain a uniform product, but also causes various drawbacks such as failure of various parts of the furnace.

The present invention eliminates the various problems and drawbacks of the conventional roller hearth kiln as much as possible, provides a uniform firing state, has fewer failures, and even in the case of rare failures, is much more efficient than before. The purpose of the present invention is to create and provide a roller hearth kiln that can greatly improve production efficiency by allowing repairs to be completed.

[Structure of the present invention: Means for solving the problems] The present invention is a roller hearth kiln, which is a long continuous firing furnace with a frame and refractory material, and has many transfer rollers and heating means in the center of the height of the furnace. However, its new structural features are as follows.

(1) The furnace body is not only divided in the furnace length direction, but also divided into upper and lower parts at approximately the center of the height, that is, at the attachment point of the transfer roller, and a lower furnace body is simply supported by a frame; The upper furnace body is installed on the upper part of the frame and suspended via wheels from a rail running in the furnace length direction, and the connecting parts of the upper, lower, front, and rear furnace body parts are filled with monolithic refractories. The furnace body is constructed. In addition, in the present invention, when the length of the division in the furnace length direction is selectively set to 1.5 [m] or less, it is particularly favorable.

(2) A large number of transfer rollers are provided at regular intervals almost perpendicular to the furnace length direction, and both ends of each roller are slid from below by two short shaft rollers of a drive device attached to a frame provided outside the furnace body. Supported. Further, the transfer roller of the present invention is particularly advantageous when it is formed of a hollow refractory tube that is selectively open at both ends.

(3) The heating means, that is, the burner in the present invention is a uniform radiation tubular burner, and is arranged horizontally with respect to the furnace length direction so as to uniformly radiate flame above and below the transfer roller installation surface, respectively, to the roller installation surface. The upper part of the roller installation surface is provided with a number of flame injection holes uniformly in the lateral direction on the lower side of the tubular shape, and the lower part of the roller installation surface is provided with a number of flame injection holes uniformly in the lower side of the tubular shape. It is formed by providing a large number of flame injection holes uniformly in the horizontal direction.

In addition, the burners of the present invention as described above are selectively provided in multiple rows in the furnace length direction, and can be used in accordance with changes in the properties of the object to be fired, the firing temperature, and the lengths of the preheating zone, firing zone, and cooling zone. It is formed to enable selective injection for each burner.

Next, each element in the configuration of the present invention described above will be explained. The furnace body of the kiln of the present invention has a frame formed around it, which is generally made of steel.
Supported everywhere. The connecting parts of the furnace bodies, which are divided into upper and lower parts, are formed as expansion joints with a width of about 20 [mm]. They are tied together to form a long furnace body so that the kiln can freely expand and contract in the furnace length direction due to thermal changes. Further, although it was mentioned above that the lower furnace body below the transfer roller is simply supported by the lower part of the frame, the supporting state is not pin-coupled but slidingly supported.

The transport rollers, ie the hearth rollers formed by a number of refractory rollers, are formed so as to always maintain an average horizontal level. Furthermore, both ends of the roller according to the present invention are slidably supported on the two short-axis rollers of the drive unit, as described above, and the direction of the slide is formed in the direction of the axis of the transfer roller. Ru.
Further, since the short axis roller of the drive unit must also perform the same circumferential movement at the point of contact with the transfer roller, the rotation directions thereof are formed to be opposite to each other. A flange is provided near the frame attachment portion of the short axis roller in order to limit the amount of movement of the transfer roller in the axial direction and prevent the transfer roller from falling off.

The drive unit and both ends of the transfer roller are formed outside the furnace at the frame, ie at room temperature.

[Function] The furnace body is divided into upper and lower parts, and it is also short in the furnace length direction.
By selectively dividing the furnace into lengths of 1.5 m or less and filling the joints with elastic monolithic refractories, distortion stress will not occur in the furnace body when it expands and contracts due to thermal changes. . Since the upper furnace body is suspended from the rails of the upper frame via wheels, it can be easily moved in the furnace length direction.

Both ends of the transfer roller are supported by two drive rollers from below and rotate in the transfer direction due to the weight of the object to be heated and the transfer roller, and the cylindrical contact described above, but both ends are slidably supported. Therefore, even if it expands due to heating, it can move freely in the axial direction of the transfer roller, so no strain stress is generated.
Additionally, these transfer rollers are formed as hollow refractory tubes with both ends protruding outside the furnace, allowing air at a temperature close to room temperature to enter and exit the roller tubes. Unlike rollers, which are closed at one end for the drive shaft, they do not overheat or become over-softened. Therefore, the transfer roller installation surface of the present invention maintains a highly accurate flat surface even during heating of the object to be fired.

The burner of the present invention is also different from the conventional type in which the flame is blown from the side wall to the center, and a uniform radiation tubular burner is used which has a large number of flame injection holes uniformly in the direction of the entire furnace width. Radiation is evenly radiated from above and below the surface, and the object to be fired is heated very uniformly from above and below.

[Example] Hereinafter, an example of the present invention will be described based on the drawings. As shown in Figure 1, the furnace body is divided into an upper and lower furnace body 1 and a lower furnace body 2 through a gap (indicated by dimension a in Figure 2), and also in the furnace length direction (direction perpendicular to the page). The furnaces are divided into small sections with a furnace length of approximately 1.5 [m] (indicated by dimension L in Figure 2), and are arranged in series in the furnace length direction with a gap of approximately 20 [mm] width (indicated by dimension a in Figure 2). It is formed from things arranged in . As mentioned above, the furnace body was divided into upper and lower parts and divided in the furnace length direction.
This alleviates thermal changes caused by thermal expansion and contraction of the furnace body. As shown in FIG. 2, a monolithic refractory 21 is interposed within the gap. Monolithic refractories 21
As described above, for example, a soft board such as mullite wool is used, but the board is not limited thereto. Note that although the monolithic refractories 21 are connected to the upper furnace body 1 and the lower furnace body 2, relatively loose bolt connections are employed, which are not shown, and function to alleviate deformation of the furnace body due to thermal changes.

A large number of transfer rollers 3 are arranged in parallel at substantially right angles to the furnace length direction, and are horizontally disposed in the gap between the upper furnace body 1 and the lower furnace body 2. Its ends are placed outside the furnace body to prevent heat effects. In particular, the transfer roller of this embodiment is formed by a hollow tube of refractory material. One end side of the transfer roller 3 is supported from below by the short axis rollers 6 and 7 of the driving device in the state shown in the cross-sectional view in FIG. It is supported from below by short shaft rollers 6 and 7. Thereby, the transfer roller 3 is supported at both ends so as to be able to slide freely in the axial direction. As shown in FIG. 4, the drive device includes short shaft rollers 6, 7 and a chain wheel 8 connected thereto.
and a chain 9 connected to a drive source (not shown) to drive the chain wheel 8. Further, the short shaft rollers 6 and 7 are arranged in parallel at appropriate intervals, are rotatably supported on the support block 10, are disposed so as to support the transfer roller 3 on the outer periphery between them, and are mounted Flanges 22 and 23 are formed at the end of the frame 11, and the collars 2
2 and 23 come into contact with the end face of the support block 10, and are restrained from moving in the axial direction. These collars also limit the range of axial sliding movement of the slidingly supported transport roller.

Further, the chain 9 is driven and rotated by the power of an electric motor, etc., and as the chain wheel 8 rotates, the short axis rollers 6 and 7 rotate in the same direction, and the weight of the transfer roller 3 and the to-be-fired material 12 loaded thereon are rotated.
Since the weight of the kiln acts on the contact portion, the transfer roller rotates and transfers the object to be fired 12 in the furnace length direction within the kiln. Furthermore, the support block 10 is connected to the frame 1
1 is maintained.

The frame 11 is a frame-like member that is immovably fixed on the base surface 24 and is arranged to surround the entire furnace body. The lower furnace body 2 is fixed to the frame 11,
The upper furnace body 1 is suspended and supported from a rail-shaped part attached to the upper part of the frame 11.

That is, one end of a hanging plate 13 is fixed to the front side of the upper furnace body 1, and a wheel 14 pivoted to the other end of the hanging plate 13 rolls along a rail 15 in the furnace length direction. It is fixed to the frame 11 and formed in the furnace length direction. Therefore, the upper furnace body 1 is suspended and supported so as to be slidable in the furnace length direction.

Next, as shown in FIG. 1, the radiant tubular burners 4 are installed horizontally on the upper furnace body 1 and the lower furnace body 2, and approximately at right angles to the longitudinal direction of the furnace bodies, and are arranged in large numbers on both sides of the transfer roller surface. Arranged in columns. That is, as shown in FIG. 3a, when viewed from the bottom or top view, there is an elongated hollow flame tube 17 and the tube 1 surrounding one end of the elongated hollow flame tube 17.
8, a nozzle pipe 16 engaged with the one end, and a gas pipe 1 connected to the nozzle pipe and communicating with a fuel gas source.
9 and an air pipe 20 connected to an air source are each connected to a control means 29 and are configured to be controlled to open and close. Since the control means may be a normal one, a detailed explanation thereof will be omitted.

The hollow flame tube 17 of the radiant tubular burner 4 is provided with flame ejection holes 5 at appropriate intervals along its axial direction. The hole 5 is formed at a position exactly facing the transfer roller surface when the hollow flame tube 17 is disposed in the upper furnace body 1 and the lower furnace body 2. That is, those on the upper furnace body 1 side are formed downward, and those on the lower furnace body 1 side are formed upward.

Gas, which is an example of fuel, enters through the nozzle pipe 16, mixes with air from the air pipe 20, becomes a combustion flame, passes through the hollow flame tube 17, is ejected from the hole 5, and is loaded onto the transfer roller 3 to be fired. Heat the object 12.

The control means 29, as described above, controls the radiation tube burner 4.
Controls the opening and closing of the
Depending on the firing temperature, the preheating zone, the length of the firing zone, the cooling zone, etc., all or only some of them can be operated.

With the above configuration, the effects of this embodiment are as follows.

() The furnace body is selectively divided into sections of 1.5 [m] or less not only in the upper and lower directions, but also in the furnace length direction, and the contact areas are filled with variable volume mullite wool, which almost eliminates thermal distortion of the furnace body due to temperature changes. Can be completely absorbed. In addition, the transfer roller is made of refractory material, has sliding support at both ends, and is installed outside the furnace.In particular, in this example, it is a hollow tube, so normal air always flows in and out of the roller tube. The traditional overheating deformation of the rollers hardly occurs, and therefore the transfer of the objects to be burnt is different from the conventional one, which is more precise and uniform. Combined with the creation of the radiant tube burner, the objects to be burnt are heated extremely uniformly, e.g. Ceramic materials also have the effect of largely eliminating the drawbacks of conventional techniques, such as almost no deformation due to firing.

() When a material to be fired is transferred at a transfer speed of 300 [mm/min] through a furnace whose total length is 10 [m] and the maximum internal temperature is 1200 [℃], in the conventional technology, while the material to be baked is being transferred, Whereas 120 to 150 [mm] of left and right deflection occurred at the inlet and outlet, with the device of the present invention, the deflection was only 30 [mm] or less, and the material to be fired was moved very smoothly by the transfer rollers. It has become clear that he will be transferred to

() In the device of the present invention, the combustion flame from the radiant tubular burner 4 is uniformly injected in the width direction of the furnace.
Even if the furnace width is 1000 mm or more, the temperature in the width direction is uniform. For example, when using a conventional burner, in the case of a furnace with a width of 1000 [mm], the temperature difference between the central part and the outside part of the furnace fluctuates in the range of 5 to 20 [°C], making it unstable. A stable temperature distribution can be maintained within a temperature difference of 2 [° C.].

Since the above-mentioned embodiment is only an example of the device of the present invention, the technical scope of the present invention is not limited by the contents of the present embodiment.

[Effects of the Present Invention] As described above in detail, the roller hearth kiln of the present invention exhibits significantly superior effects in the following points as compared to conventional similar devices.

(1) By dividing the furnace body into appropriate lengths not only in the upper and lower directions but also in the furnace length direction and filling the joints with monolithic refractories whose volume can change freely, thermal distortion due to temperature changes is significantly reduced compared to conventional methods. can be reduced,
Breakdowns will also be reduced.

(2) By forming the upper furnace body into a structure that makes it easy to disassemble, hang, and move, it is extremely convenient for troubleshooting or inspection, and the time required can be reduced to about 1/10 of conventional technology, making the overall As a result, operating efficiency is greatly improved.

(3) Since both ends of the transfer roller of the device of the present invention are slidably supported, thermal distortion in the axial direction due to temperature changes does not occur, and therefore, unlike conventional devices, the transfer roller does not deform. Moreover, this transfer roller is made of refractory material and is particularly selectively formed as a hollow tube, with both ends supported by a frame outside the furnace, so that the transfer roller tube is always exposed to room temperature air. Because of the inflow and outflow, the temperature of the roller tube does not rise much, so it does not overheat and high temperature softening deformation does not occur. Therefore, the objects to be fired are transported through the furnace very smoothly without any overlap as in the past, and the firing is uniform, and the objects to be fired do not deform as in the past. do not have.

(4) The uniform radiation tubular burner in the device of the present invention is completely different from the side wall blow burner conventionally used in kilns. In addition to radiating flame evenly from above and below to the heated object above, the burner itself also radiates uniform heat, resulting in unique uniform heating performance never seen before. It has the unique ability to radiate flame more evenly. Therefore, there is no need to partially heat the transfer roller and the object to be heated as in the conventional method, and the product is heated uniformly, so there is almost no deformation of the product.

(5) The uniform heating characteristic of the device of the present invention is particularly noticeable in this type of kiln, which is sometimes wide, so it has become possible to develop a roller hearth kiln that is wider than conventional kilns.

(6) By using the radiant tubular burner in the device of the present invention, the object to be fired can be heated evenly and directly without any waste, thereby increasing the overall thermal efficiency.
It can be improved by 15% without 10.

[Brief explanation of drawings]

Fig. 1 is an explanatory cross-sectional view in the direction perpendicular to the furnace length showing the configuration of an embodiment of the roller hearth kiln according to the present invention, Fig. 2 is a partial perspective view showing the general shape of the embodiment in the direction of the furnace length, and Fig. 3 3a is a horizontal cross-sectional view of the upper radiant tubular burner of the example (a view cut horizontally at the center axis and viewed from the direction of the arrow in FIG. 1), and FIG. 3b is a vertical sectional view of the upper radiant tubular burner of the example. Fig. 3c is a partially enlarged axial sectional view of the radiation tubular burner of the embodiment (viewed from the direction of the arrow in Fig. 1); Fig. 4 is a part showing the structure of the drive device of the embodiment. FIG. 5 is an enlarged top view, FIG. 5 is a side view showing the engagement state between the short axis roller and the transfer roller as viewed from arrow V in FIG. 4, and FIG. 6 is a sectional view taken in the direction perpendicular to the furnace length, showing the conventional furnace structure. It is. 1... Upper furnace body, 1A... Furnace body, 2... Lower furnace body, 3, 3A... Transfer roller, 4... Radiation tubular burner, 5... Flame injection hole, 6, 7... Short axis Roller, 8,8A...Chain wheel, 9,9A...
... Chain, 10 ... Support block, 11 ... Frame, 12 ... Part to be fired, 13 ... Hanging plate, 4
...Wheel, 15...Rail, 16...Nozzle pipe,
17... Hollow flame tube, 18... Outer tube, 19... Gas pipe, 20... Air pipe, 21... Monolithic refractory, 22, 23... Tsuba, 24... Foundation surface, 25,
26... Bracket, 27, 28... Burner, 2
9... Control means, 30... Drive device.

Claims (1)

[Claims] 1. It is formed into a rectangular shape by a ceiling, a floor surface, and both side walls made of refractory material, and has an inlet for firing materials, an outlet, and the inside of the furnace, which are on the same plane at regular intervals approximately perpendicular to the length direction of the furnace. A roller hearth kiln having a large number of transfer rollers whose upper side rotates in the direction of movement of the object to be fired, and means for heating the object to be fired, comprising: a furnace body, both ends of the transfer roller, and the transfer roller; Provided with an immovable frame supporting the drive unit,
The furnace body is divided vertically and in the furnace length direction with appropriate gaps to form an upper furnace body and a lower furnace body which are also divided in the front-rear direction, and monolithic refractories are interposed in the gaps to completely separate the furnace body. A furnace body is formed continuously, the lower furnace body is simply supported by the lower part of the frame, the upper furnace body is movably supported by the upper rail of the frame, and the transfer roller is supported at both ends thereof. Each of the two short shaft rollers supported by the frame and having at least one end driven by a friction drive device is supported from below, and is provided so as to be able to slide within a predetermined range in the axial direction of the transfer roller. , Radiation tubular burners are provided above and below each of the roller installation surfaces in a direction transverse to the furnace length direction, and a large number of holes for ejecting combustion flame are uniformly provided in the longitudinal direction of each burner toward the transfer roller surface. A roller hearth kiln characterized by the fact that it is perforated. 2 The length of the subsection in the furnace length direction of the furnace body is 1.5
[m] or less, the roller hearth kiln according to claim 1. 3. The roller hearth kiln according to claim 1 or 2, wherein the transfer roller is a refractory hollow tube with both ends open to the atmosphere. 4. The radiant tubular burners are arranged in multiple rows substantially perpendicular to the furnace length direction, and each burner 4. A roller hearth kiln according to any one of claims 1 to 3, which has control means for selectively using the kiln.