A method of controlling the production of a bubble at the bottom of a tin bath during the firing of a float glass tin bath

Abstract

The application provides a method for controlling bubble generation at the bottom of a tin bath during the baking of a float glass tin bath, wherein the bottom of the tin bath is provided with a groove, the groove is divided into left and right sections and a middle section, the upper part of the middle section extends inward to form a limiting part, the lowermost end of the limiting part has a gap in the height direction with a graphite block when the graphite block is placed on the bottom, and the method comprises the following steps: step 1: when the tin bath is cold, a predetermined number of graphite blocks are sequentially placed on the groove at the bottom of the tin bath, the bottom of the graphite block is separated from the bottom of the groove to be clamped by the limiting part of the groove, the floating state of the graphite block is simulated, the floating height is measured, and graphite blocks with consistent floating heights are screened; step 2: the graphite blocks are preheated; step 3: tin liquid is added to the tin bath to a preset height, and when the temperature of the tin liquid in the tin bath is within the range of A-B, the graphite blocks are hot-mounted into the groove to form a graphite dam.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of float glass production, in particular to a method for controlling the generation of tank bottom bubbles during the baking of a float glass tin bath. BACKGROUND

[0002] The float glass forming process refers to a process in which a high-quality glass liquid that has been melted, clarified and homogenized in a melting furnace is introduced onto the surface of tin liquid in a tin bath, and under the action of an external force of a tin bath edge machine, the glass liquid is spread, polished and formed into a high-quality flat glass substrate with a certain width and thickness.

[0003] However, during the operation of float glass production, due to temperature fluctuations in the tank, tin liquid invades the brick joints, the gas in the gap is squeezed out by the tin liquid and overflowed upward along the brick joint, reaches the glass ribbon below or in the glass ribbon floating on the tin liquid surface through the tin liquid, and forms a tank bottom bubble. Once a tank bottom bubble appears on the glass, it will affect the glass quality for an entire kiln period (8 to 10 years), which will seriously affect the quality of the glass production. It has been proven that the position of the tank bottom bubble is mainly in the region of the two graphite dams.

[0004] The graphite dam is a device for adjusting the convection of tin liquid and improving the surface quality of float glass, which is embedded in the tin bath bottom brick and submerged in the molten tin liquid during normal production, and covered by the formed glass plate.

[0005] The graphite dam is generally installed in a cold state when the tin bath is built. In the cold state, the graphite dam is attached to the tank bottom brick, which causes some brick joints and brick surfaces to be blocked by the graphite dam. During the baking of the tin bath before production, the blocked tank bottom brick, the gap between the tank bottom brick and the brick, the gap between the tin bath bottom brick and the graphite block, and the moisture inside the graphite block are not fully and uniformly baked, and the gas is not easily removed. This leads to the generation of tank bottom bubbles during the operation of float glass production when the temperature in the tank fluctuates, which seriously affects the quality of the glass production.

[0006] There are currently two solutions to the problem of tank bottom bubbles in the prior art:

[0007] First, change the structure of the tin bath. CN211620354U provides a structure under the tank bottom brick of a float glass tin bath, in which a graphite material with a predetermined thickness is laid in the gap between the tank bottom brick and the tank bottom steel plate. The presence of the graphite material eliminates the excess air under the brick, prevents the downward flow of hot tin liquid, and blocks the generation of tank bottom bubbles. However, this method requires redesigning the structure of the tin bath, which needs to be completed before the production line is put into operation. Once the laying is completed, it cannot be changed and is not convenient for adjustment during production. In addition, it requires additional investment in graphite materials and material laying.

[0008] Second, post-processing. CN207793043U is a device for eliminating bubbles in a tin bath during float glass production, which generates negative pressure through a vacuum pump to remove bubbles, thereby solving the problem of the influence of bottom opening bubbles on the quality of float glass production. However, this method requires additional equipment investment, and there are uncertain factors such as failure or stop during use, which may lead to the risk of bottom bubble formation without negative pressure.

[0009] CN206970460U provides a baffle for a tin bath, which can remove bubbles by replacing the graphite baffle online when bottom bubbles occur. However, this method requires skilled operators to operate, which cannot guarantee production safety. SUMMARY

[0010] The main technical problem to be solved by the present application is to provide a method for controlling the generation of bottom bubbles during the baking of a float glass tin bath, which installs a graphite baffle during the hot baking of the tin bath before production, without the need to change the structure of the tin bath and invest in additional equipment, to control the generation of bottom bubbles in the glass production process from the source.

[0011] To solve the above technical problems, the present application provides a method for controlling the generation of bottom bubbles during the baking of a float glass tin bath, wherein the bottom of the tin bath is provided with a groove, the groove is divided into left and right sections and a middle section, the upper part of the middle section extends inward to form a limiting part, and when the graphite block is placed on the bottom, the lowermost end of the limiting part has a gap with the graphite block in the height direction, the method comprising the following steps:

[0012] Step 1: When the tin bath is cold, a predetermined number of graphite blocks are placed in the groove at the bottom of the tin bath in order, the bottom of the graphite block is separated from the limiting part of the groove, the floating height is measured in the simulated floating state of the graphite block, and the graphite blocks with consistent floating height are selected;

[0013] Step 2: Preheat the graphite blocks;

[0014] Step 3: Add tin liquid to the tin bath to a predetermined height, and when the temperature of the tin liquid in the tank is within the range of A-B, install the graphite blocks in the groove to form a graphite baffle.

[0015] In some embodiments, the graphite block includes a bottom and an upper part protruding upward from the bottom, and the width of the upper part is less than that of the bottom.

[0016] In some embodiments, the tin bath includes a wide section, a narrow section and a connecting section, and the groove for placing the graphite blocks is respectively provided transversely at the bottom of the wide section and the narrow section.

[0017] In some embodiments, the specific preheating method in step 2 is to place the graphite blocks beside the flow channel of the tin bath for preheating during the baking of the tin bath.

[0018] In some embodiments, the graphite blocks are preheated in a high-heat area beside the flow channel.

[0019] In some embodiments, the graphite blocks are preheated in a high-heat area beside the flow channel.

[0020] In some embodiments, the temperature of the tin liquid in step 3 is in the range of 750-950℃.

[0021] In some embodiments, the pre-set height in step 3 is the immersion depth of the tin liquid.

[0022] In some embodiments, the specific method of hot installation of the graphite blocks in step 3 is as follows: according to the sequence in step 1, the graphite blocks are installed from the middle block first, and then pushed into the middle section of the groove after being placed in the left and right sections of the groove, forming a graphite baffle.

[0023] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0024] 1. The present application preheats the graphite blocks during the tin bath baking period before production, and installs the graphite baffle in a hot state, avoiding the adhesion of the graphite baffle to the bottom brick of the tin bath, which causes gas exclusion to be blocked, thereby controlling the generation of bottom bubbles at the source, greatly improving the production quality of glass, and reducing economic losses.

[0025] 2. The present application is operated during the baking period before production, without the need to redesign the structure of the tin bath or invest in additional equipment, saving economic costs.

[0026] 3. The present application is operated during the baking period before production, without the need to replace the graphite baffle in production, ensuring production safety.

[0027] DRAWINGS

[0028] Figure 1 is a front view of the graphite block;

[0029] Figure 2 is a top view of the graphite block;

[0030] Figure 3 is a schematic view of the graphite block being placed in the left and right sections of the groove;

[0031] Figure 4 is a schematic view of the graphite block being embedded in the middle section of the groove;

[0032] Figure 5 is a schematic view of the graphite block floating up when being embedded in the middle section of the groove;

[0033] Figure 6 is a schematic view of the tin bath;

[0034] Figure 7 Figure for the graphite dam of Example 1.

[0035] Reference signs: 1, graphite block; 2, tin bath bottom; 21, groove; 211, left part rectangular groove; 212, dovetail groove; 213, right part rectangular groove; 3, tin bath wall; 4, tin liquid; 5, glass ribbon. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application; obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application, and all other embodiments obtained by a person of ordinary skill in the art without creative labor based on the embodiments in the present application shall fall within the scope of protection of the present application.

[0037] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "left", "right", "upper / lower end" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0038] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "provided with", "sleeved / connected", "connected" and the like should be broadly understood, for example, "connected" can be wall-mounted connection, can be detachable connection, or integral connection, can be mechanical connection, can be electrical connection, can be direct connection, can be indirect connection through an intermediate medium, can be internal communication of two elements, and for a person of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] Example 1

[0040] Reference Figures 1-6 The present embodiment provides a method for controlling the generation of bubbles on the bottom of a tin bath during the baking of a float glass tin bath, which is suitable for a 800 tons / day float glass production line.

[0041] As Figures 3-6As shown, in the present embodiment, the tin bath bottom 2 is provided with a groove 21 for installing the graphite baffle, in order to conveniently and labor-savingly install the graphite block 1 into the groove 21 to form the graphite baffle, the groove 21 is divided into left and right sections and a middle section, when installing the graphite baffle, first place the graphite block 1 in the left part of the rectangular groove 211 or the right part of the rectangular groove 213, and then push it into the middle section. The upper part of the middle section extends inward to form a limiting part to form a dovetail groove 212 in the shape of a dovetail, when the graphite block 1 is placed in the groove 21, the lowermost end of the limiting part has a gap in the height direction with the graphite block 1, so that the graphite block 1 has a space for floating after the tin liquid is added, and the existence of the limiting part can limit the graphite block 1 from floating away, thereby forming a graphite baffle.

[0042] The method for controlling the generation of bubbles on the bottom of the tin bath during the baking of the float glass tin bath comprises the following steps:

[0043] Step 1: Pre-installation of the graphite baffle.

[0044] In order to ensure that the graphite block 1 can be smoothly slid into the dovetail groove 212 of the bottom brick during subsequent hot installation, and that the floating height of the graphite block 1 is consistent, the graphite baffle is pre-installed. In a cold state, a predetermined number of graphite blocks 1 are placed in the groove 21 of the tin bath bottom in order, the bottom of the graphite block 1 is separated from the limiting part of the groove 21, the floating state of the graphite block 1 is simulated and the floating height is measured, and graphite blocks 1 with consistent floating heights are selected.

[0045] In the present embodiment, the specific steps of pre-installing the graphite baffle are as follows: first, place the graphite block 1 into the left part of the rectangular groove 211, and then push it into the middle dovetail groove 212, place 25 graphite blocks 1 in order into the dovetail groove 212 of the tin bath bottom 2, so that the graphite blocks 1 form a first graphite baffle that has not floated in the width direction along the wide section of the tin bath.

[0046] Secondly, from left to right, one person holds up the graphite block 1 with both hands to the limiting part of the dovetail groove 212 so that it cannot be raised any higher, simulates the floating state of the graphite block 1, measures the floating height, makes a record, selects graphite blocks 1 with consistent floating heights that meet the process requirements, and for graphite blocks 1 that do not meet the process requirements, they can be polished and modified to meet the process requirements, or they can be replaced.

[0047] As a simple alternative to the present embodiment, the floating state of the graphite block 1 can also be simulated by placing a wooden block at the bottom to the limiting part of the dovetail groove 212.

[0048] In order to enable the smooth sliding of the graphite block 1, in the present embodiment, the smoothness of the sliding of the graphite block 1 in the dovetail groove 212 is further tested by pushing and pulling back and forth in the dovetail groove 212 and pushing in and out during installation, and the graphite block 1 that is not smooth in sliding can be modified and polished.

[0049] In order to facilitate the installation according to the installation sequence of the graphite block 1 in the cold state during the hot state installation, ensure that the graphite baffle in the hot state installation is consistent with the graphite baffle in the cold state installation, and mark the graphite block 1 according to the installation sequence, make the number mark from left to right 1 to 25, and ensure that the number mark of the graphite block 1 that does not meet the process requirements is not changed after polishing and modification, and the number of the replaced graphite block 1 remains consistent before replacement.

[0050] In the present embodiment, the tin tank includes a wide section, a narrow section and a connecting section, and the grooves 21 for placing the graphite blocks are respectively transversely arranged at the groove bottoms 2 of the wide section and the narrow section. By using the same pre-installation method, 17 graphite blocks 1 are installed in the dovetail grooves 212 of the narrow section of the tin tank, forming the second row of graphite baffles that are not floated. Similarly, the number mark from left to right is made 1 to 17.

[0051] As a simple replacement of the present embodiment, the graphite block 1 can also be installed from the right rectangular groove 213, and the number mark from right to left is made for the 25 graphite blocks 1 of the graphite baffle of the wide section of the tin tank and the 17 graphite blocks 1 of the graphite baffle of the narrow section of the tin tank.

[0052] Step 2: Preheat the graphite block 1.

[0053] In order to prevent the occurrence of groove bottom bubbles due to the internal moisture of the graphite block 1, the graphite block 1 is preheated to remove the internal moisture of the graphite block 1.

[0054] In the present embodiment, the specific steps of preheating the graphite block 1 are as follows: during the baking of the tin tank, the graphite block 1 is placed in the high-heat area beside the flow channel of the tin tank, and the heat emitted by the flow channel baking is used for preheating to remove the internal moisture of the graphite block 1. In this way, the graphite block 1 is baked at the same time as the tin tank baking by using the heat emitted by the flow channel baking, which can save process cost and resources, and placing in a high-heat place can improve the baking efficiency of the graphite block 1.

[0055] In order to enable the graphite block 1 to be baked sufficiently and uniformly, the graphite block 1 is dispersed and placed beside the flow channel for preheating, and the baking position is regularly changed and the baking surface is turned over.

[0056] Step 3: Hot state installation of graphite baffle.

[0057] Add molten tin 4 to the tin bath to a preset height. When the temperature of the molten tin 4 in the bath is within the AB range, install the graphite block 1 in the groove 21 while it is still hot to form a graphite baffle. This ensures that the graphite block 1 and the tin bath are properly baked when the graphite baffle is installed, and there is basically no source of air bubbles. Even if there are still sources of air bubbles, the graphite block 1 is in a floating state during installation and can continue to be discharged before production.

[0058] In this embodiment, the specific steps for hot-installing the graphite retainer are as follows: When molten tin 4 is added to the tin bath until it covers the bottom brick, and the temperature of the molten tin 4 in the tin bath is between 750℃ and 950℃, the graphite retainer is hot-installed. When the molten tin 4 reaches 750℃-950℃, the bottom brick and graphite block 1 of the tin bath are basically baked to the required temperature, and there will be virtually no more sources of air bubbles. Furthermore, at this time, the density of tin (e.g., the density of tin at 800℃ is 6.574 g / cm³) is... 3 The density of graphite is 2.25 g / cm³. 3 This allows graphite block 1 to float on the surface of the molten tin, and the buoyancy required to be overcome during installation is relatively small. Even if there is still air in the tank brick structure and graphite block 1, after the graphite block 1 is embedded in the dovetail groove 212 of the bottom brick of the tank, it will float under the buoyancy of the molten tin 4, avoiding the tight fit between the tank brick structure and graphite block 1. The remaining air can continue to be discharged before production, ensuring that the air can be completely discharged.

[0059] In this embodiment, in order to improve the visualization effect when installing the graphite block 1 into the dovetail groove 212 and facilitate the alignment of the graphite block 1 with the dovetail groove 212, the dovetail groove 212 of the bottom brick is faintly visible on the surface of the molten tin in the tin bath. At this time, the molten tin surface will not be too deep to directly see the position of the dovetail groove 212, which would increase the difficulty of aligning the graphite block with the dovetail groove 212 when installing it.

[0060] like Figures 1-2 As shown, in this embodiment, the graphite block 1 includes a bottom and an upper part that protrudes upward from the bottom. The width of the upper part is smaller than that of the bottom. In this way, when the graphite block 1 floats up, the bottom of the graphite block 1 can be stuck in the limiting part of the dovetail groove so that the graphite block does not float away, and the upper part can protrude from the brick surface of the bottom brick of the groove to form a graphite retaining wall.

[0061] In this embodiment, the specific operation steps for hot installation of the graphite block 1 to form the graphite dam are as follows: the operator wears labor protection articles, takes the graphite block 1 to be installed with a large vice glove or a ceramic fiber blanket, places it vertically to the center line of the tin bath on the tin bath wall brick 3, buckles the upper part of the graphite block 1 with the clamping groove of the hot installation graphite dam installation device, and pushes the graphite block 1 into the tin bath by using the handle to align the rectangular groove 211 of the tin bath bottom brick. The handle is adjusted to be horizontal, and the handle is slightly pressed downward to make the graphite block 1 slide into the rectangular groove 211. The handle is continuously adjusted to be horizontal, and the graphite block 1 is slowly pushed into the dovetail groove 212 in the direction of the center line of the tin bath, that is, one graphite block 1 is installed.

[0062] In this way, according to the sequential marks made during pre-installation, the graphite block 1 marked 12 in the middle of the left side of the wide section of the tin bath is first installed, which is installed in the middle of the dovetail groove 212, and then the graphite blocks 1 marked 11 to 1 are sequentially installed. Then, turning to the right side of the wide section of the tin bath, the graphite block 1 marked 13 is first installed in the middle, and then the graphite blocks 1 marked 14 to 25 are sequentially installed. All the graphite blocks 1 float up under the action of the tin liquid buoyancy, the bottom is suspended, the upper part is protruded from the groove surface, and the first graphite dam of the wide section of the tin bath is formed.

[0063] Similarly, the graphite block 1 marked 8 in the middle of the left side of the narrow section of the tin bath is first installed, which is installed in the middle of the dovetail groove 212, and then the graphite blocks 1 marked 7 to 1 are sequentially installed. Then, turning to the right side of the narrow section of the tin bath, the graphite block 1 marked 9 is first installed in the middle, and then the graphite blocks 1 marked 10 to 17 are sequentially installed. All the graphite blocks 1 float up under the action of the tin liquid buoyancy, the bottom is suspended, the upper part is protruded from the groove surface, and the second graphite dam of the narrow section of the tin bath is formed.

[0064] As a simple replacement of this embodiment, when the pre-installation of the graphite dam is from the rectangular groove 213 of the right side, then according to the above idea, the graphite blocks 1 marked 12 to 1 are first sequentially installed from the right side of the wide section of the tin bath, and then the graphite blocks 1 marked 13 to 25 are installed from the left side of the wide section of the tin bath. Similarly, the graphite blocks 1 marked 8 to 1 are first sequentially installed from the right side of the narrow section of the tin bath, and then the graphite blocks 1 marked 9 to 17 are installed from the left side of the narrow section of the tin bath.

[0065] Embodiment 2

[0066] This embodiment is suitable for a 600 tons / day float glass production line. The main difference between this embodiment and embodiment 1 is that the first graphite dam of the wide section of the tin bath is composed of 22 graphite blocks 1, and the second graphite dam of the narrow section of the tin bath is composed of 14 graphite blocks 1.

[0067] In the hot installation of the graphite block, the graphite block 1 with the label 11 in the middle of the tin bath wide section is first installed in the middle of the dovetail groove 212, and then installed from the label 10 to 1. Then turn to the right side of the tin bath wide section, install the graphite block 1 with the label 12 in the middle, and then install from the label 13 to 22. All the graphite blocks 1 float up under the tin liquid buoyancy, the bottom is suspended, the limiting part of the dovetail groove 212 is clamped, the upper part protrudes from the groove surface, and the first graphite block of the tin bath wide section is formed. Similarly, the graphite block 1 with the label 7 in the middle of the tin bath narrow section is first installed in the middle of the dovetail groove 212, and then installed from the label 6 to 1. Then turn to the right side of the tin bath narrow section, install the graphite block 1 with the label 8 in the middle, and then install from the label 9 to 14. All the graphite blocks 1 float up under the tin liquid buoyancy, the bottom is suspended, the limiting part of the dovetail groove 212 is clamped, the upper part protrudes from the groove surface, and the second graphite block of the tin bath narrow section is formed. The rest is the same as example 1, and will not be repeated here.

[0068] The number of graphite blocks can be increased or decreased as needed, and is not limited to the number of examples 1 and 2.

[0069] The above is only a preferred specific embodiment of the present application, but the design concept of the present application is not limited thereto. Any skilled person in the art can make non-essential changes to the present application within the technical scope disclosed by the present application, and such changes shall not be regarded as departing from the scope of the present application.

Claims

1. A method for controlling the generation of bubbles at the bottom of a float glass tin bath during baking, characterized in that, The bottom of the tin bath has a groove, which is divided into left and right sections and a middle section. The upper part of the middle section extends inward to form a limiting part. When the graphite block is placed at the bottom of the bath, there is a gap between the lowermost end of the limiting part and the graphite block in the height direction. The method includes the following steps: Step 1: When the tin bath is cold, place a predetermined number of graphite blocks into the groove at the bottom of the tin bath in sequence, detach the bottom of the graphite blocks from the bottom of the bath and lock them into the groove limit part to simulate the floating state of the graphite blocks and measure the floating height, and select graphite blocks with the same floating height. Step 2: Preheat the graphite block; Step 3: Add molten tin to the tin bath to the preset height, and when the temperature of the molten tin in the bath is within the range of 750℃-950℃, install graphite blocks in the groove to form a graphite retainer.

2. The method for controlling the generation of bubbles at the bottom of the float glass tin bath during baking according to claim 1, characterized in that, The graphite block includes a bottom and an upper part that protrudes upward from the bottom, the width of the upper part being smaller than that of the bottom.

3. The method for controlling the generation of bubbles at the bottom of the float glass tin bath during baking according to claim 2, characterized in that, The tin bath includes a wide section, a narrow section, and a connecting section, and the groove for placing the graphite block is respectively arranged horizontally at the bottom of the wide section and the narrow section.

4. The method for controlling the generation of bubbles at the bottom of the float glass tin bath during baking according to claim 1, characterized in that, The specific preheating method in step 2 is as follows: During the tin bath baking process, place the graphite block next to the tin bath flow channel for preheating.

5. The method for controlling the generation of bubbles at the bottom of the float glass tin bath during baking according to claim 4, characterized in that, The graphite block is placed in a high-heat area next to the flow channel for preheating.

6. The method for controlling the generation of bubbles at the bottom of the float glass tin bath during baking according to claim 5, characterized in that, Graphite blocks are placed separately next to the flow channel for preheating.

7. The method for controlling the generation of bubbles at the bottom of the float glass tin bath during baking according to claim 1, characterized in that, The preset height mentioned in step 3 is the bottom brick surface of the molten tin immersion tank.

8. The method for controlling the generation of bubbles at the bottom of the float glass tin bath during baking according to claim 1, characterized in that, The specific method for hot-installing graphite blocks in step 3 is as follows: following the sequence described in step 1, start by installing the middle block. After placing the graphite blocks into the left and right grooves respectively, push them into the middle section of the grooves to form a graphite retainer.

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