Multi-section independent precise temperature control heating system for glass tempering furnace

Abstract

The invention belongs to the technical field of glass processing, and discloses a multi-section independent precise temperature control heating system for a glass tempering furnace, the multi-section independent precise temperature control heating system comprises a furnace body, the outer wall of the furnace body is provided with a PLC, the left side and the right side of the furnace body are both provided with conveying frames, and the conveying frames are internally provided with a plurality of first conveying rollers; a plurality of second conveying rollers are arranged in the furnace body, the interior of the furnace body is sequentially divided into a plurality of independent heating sections in the glass conveying direction, a fireproof heat insulation plate is arranged between every two adjacent heating sections, and a gap allowing glass to pass through is formed in each fireproof heat insulation plate. According to the scheme, the furnace body is divided into a plurality of independent heating sections through the physical heat insulation plates, and independent temperature measurement and PLC control of each section are combined, so that heat interference among the sections is effectively reduced, closed-loop accurate control can be performed on each section strictly according to preset temperature rise, heat preservation and soaking curves, and accurate management of the heating process of glass in the length direction is realized.

Description

Technical Field

[0001] This invention relates to the field of glass processing technology, and more specifically, to a multi-stage independent precision temperature control heating system for glass tempering furnaces. Background Technology

[0002] The glass tempering furnace is the core equipment in the production of tempered glass. It heats the glass to near its softening point and then rapidly cools it, creating compressive stress on the glass surface, thereby improving its mechanical strength and thermal stability. The uniformity of the heating process and the precision of temperature control directly determine the quality of the tempered glass (such as flatness, stress spots, and spontaneous breakage rate).

[0003] Traditional tempering furnaces typically use a single heating chamber, which has the following drawbacks: 1. Poor temperature uniformity: The longitudinal (along the glass conveying direction) and transverse temperature fields inside the furnace are difficult to control precisely. This is especially true for large or irregularly shaped glass, which is prone to stress concentration, deformation or even cracking due to uneven heating, affecting the yield and product quality.

[0004] 2. Limited adaptability: For glass of different thicknesses, materials, or with special heating curve requirements (such as Low-E glass), the fixed power and fixed heater position modes are difficult to adjust flexibly, resulting in a narrow process window.

[0005] 3. High energy consumption: In order to meet the process requirements, it is often necessary to maintain a high temperature throughout, which leads to energy waste in sections that do not need to be kept at a high temperature. In addition, there is serious thermal interference in each section, resulting in low thermal efficiency.

[0006] Therefore, there is an urgent need to develop a temperature control system that can achieve precise, segmented, independent control and dynamically adjust heating conditions to meet the production needs of high-quality, multi-variety glass tempering. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the existing technology and propose a multi-stage independent precision temperature control heating system for glass tempering furnaces.

[0008] To address the aforementioned technical problems, the present invention adopts the following technical solution: A multi-segment independent precision temperature control heating system for glass tempering furnace includes a furnace body, a PLC controller installed on the outer wall of the furnace body, conveyor frames installed on both the left and right sides of the furnace body, multiple first conveyor rollers installed in the conveyor frames, and several second conveyor rollers installed inside the furnace body. The furnace body is divided into multiple independent heating sections along the glass conveying direction, and a refractory heat insulation plate is installed between two adjacent heating sections. The refractory heat insulation plate has gaps for glass to pass through. Each heating section is independently equipped with heating components arranged above and below. The heating components include a heating box that can move relative to the inner wall of the furnace and a spacing adjustment mechanism that drives the heating box to move to adjust the distance between it and the glass plate surface. Each of the heating sections is provided with at least one pair of temperature measuring elements that extend into the working cavity of the section. The temperature measuring elements are used to detect the approximate temperature of the upper and lower surfaces of the glass plate in real time. The PLC controller is communicatively connected to the heating chamber, spacing adjustment mechanism, and temperature measuring element of each heating section. Based on the pre-stored temperature setting curves of each section and the real-time feedback from the temperature measuring element, it independently controls the heating power and the operation of the spacing adjustment mechanism in each heating section.

[0009] As a further aspect of the present invention: the refractory insulation board is an alumina ceramic fiber board fixed to the inner wall of the furnace, and the side of the refractory insulation board facing the heating section is covered with a high-temperature reflective layer.

[0010] As a further aspect of the present invention: an electric heating wire is provided inside the heating box, a blower is provided outside the furnace body, the blower supplies air into the heating box through a vent pipe, and several exhaust pipes are provided on the side of the heating box near the glass plate to spray hot air onto the glass surface for convection heating.

[0011] As a further aspect of the present invention: the heating wire is a nickel-chromium alloy heating wire, and the heating wire is arranged in a reciprocating bending shape inside the heating box to increase the heating area and heat exchange efficiency.

[0012] As a further aspect of the present invention: within any of the heating sections, the exhaust pipe outlets of the upper heating box and the lower heating box are staggered on the projection plane perpendicular to the glass conveying direction and with the axis of the second conveying roller, to prevent hot airflow from blowing directly and continuously onto the same position of the roller, and to prevent local overheating and deformation of the roller or scratches on the glass.

[0013] As a further aspect of the present invention: the spacing adjustment mechanism is a hydraulic cylinder or a servo electric cylinder, the cylinder body is fixed to the inner wall of the furnace, the end of the piston rod / push rod is rigidly connected to the corresponding heating box body, and the vent pipe is a flexible telescopic pipe to adapt to the movement of the heating box.

[0014] As a further aspect of the present invention: along the glass conveying direction, the first heating section is configured as a preheating zone, one or more heating sections in the middle are configured as main heating zones, and the heating section at the end is configured as a heat equalization and heat preservation zone. The target temperature curve of each heating section is independently set and adjusted by a PLC controller to form an optimized heating process curve.

[0015] As a further aspect of the present invention: the second conveying roller is made of heat-resistant alloy steel, and the surface of the second conveying roller is coated with an anti-adhesion ceramic coating to enhance its high temperature resistance and resistance to glass adhesion.

[0016] As a further aspect of the present invention: each heating section is provided with an independent maintenance door with an observation window and a sealing structure on the outer wall of the furnace body, which facilitates maintenance of a specific section without affecting other sections.

[0017] Compared with the prior art, the advantages of this invention are: I. This solution divides the furnace body into multiple independent heating sections through physical insulation panels. Combined with independent temperature measurement and PLC control for each section, it effectively reduces thermal interference between sections and can strictly control each section in a closed loop according to the preset heating, heat preservation and heat homogenization curves, thus realizing precise management of the heating process of the glass in the length direction.

[0018] II. In each heating section of this solution, the distance between the upper and lower heating boxes and the glass surface can be independently adjusted, thereby changing the intensity distribution of heat radiation and convection. The PLC can dynamically adjust the spacing based on the temperature feedback from the upper and lower surfaces of the glass, compensating for the temperature difference caused by the rising hot airflow, and ensuring uniform heating in the thickness direction of the glass.

[0019] Third, the staggered arrangement of the exhaust pipe and the conveyor roller axis in this solution optimizes the hot air distribution from the source, especially improving the heating effect in the area of ​​the bottom of the glass that is blocked by the roller. This, together with the "distance adjustment" function, ensures the uniformity of heating in three dimensions.

[0020] IV. Each section of this solution is equipped with an independent inspection door, which facilitates local maintenance and improves equipment availability; the heat-resistant and non-stick conveyor rollers ensure the smoothness of glass conveying; the fire-resistant insulation board and its reflective layer effectively reduce heat loss to adjacent low-temperature sections and improve thermal energy utilization. Attached Figure Description

[0021] Figure 1 This is one of the structural schematic diagrams of the present invention; Figure 2 This is the second structural schematic diagram of the present invention; Figure 3 This is a schematic diagram of the internal structure of the heating section of the present invention; Figure 4 This is a schematic diagram of the structure of the electric heating wire of the present invention.

[0022] Explanation of the labels in the diagram: 1. Furnace body; 11. Heating section; 12. Refractory insulation board; 13. High-temperature reflective layer; 14. Inspection door; 2. PLC controller; 3. Conveyor frame; 4. First conveyor roller; 5. Second conveyor roller; 6. Heating assembly; 61. Heating box; 611. Electric heating wire; 612. Blower; 613. Vent pipe; 614. Exhaust pipe; 62. Spacing adjustment mechanism; 7. Temperature measuring element. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1-4 A multi-stage independent precision temperature control heating system for glass tempering furnaces includes a furnace body 1. A PLC controller 2 is installed on the outer wall of the furnace body 1. Conveyor frames 3 are installed on both the left and right sides of the furnace body 1. Multiple first conveyor rollers 4 are installed inside the conveyor frames 3 for glass feeding and discharging. Several second conveyor rollers 5 are installed inside the furnace body 1, together forming a glass conveying line running through the furnace body. The first conveyor rollers 4 and second conveyor rollers 5 are synchronously driven by a drive mechanism (such as a motor or chain drive system, not shown in the figure) outside the furnace body 1 to achieve continuous glass conveying.

[0025] The furnace body 1 is divided into multiple independent heating sections 11 along the glass conveying direction (from left to right in the figure), for example, 3-5 sections. The first heating section 11 is configured as a preheating zone, one or more heating sections 11 in the middle are configured as main heating zones, and the heating section 11 at the end is configured as a heat homogenization and heat preservation zone. The target temperature curve of each heating section 11 is independently set and adjusted by the PLC controller 2.

[0026] A refractory heat insulation board 12 is installed between two adjacent heating sections 11. The refractory heat insulation board 12 is preferably made of alumina ceramic fiber board and is fixed to the inner wall of the furnace body 1. The side of the board facing the heating section 11 is covered with aluminum foil or a high-temperature resistant metal ceramic reflective layer as a high-temperature resistant reflective layer 13 (such as aluminum foil or a special ceramic coating) to maximize the blocking of radiative heat transfer between adjacent sections and enhance the independence of the sections. The refractory heat insulation board 12 has gaps of sufficient height to allow glass to pass through.

[0027] Within each heating zone 11, heating components 6 are independently arranged vertically. Each heating component 6 includes a heating box 61 that can move relative to the inner wall of the furnace body 1, and a spacing adjustment mechanism 62 that drives the heating box 61 to adjust its distance from the glass plate surface. Figure 4As shown, the heating chamber 61 is densely packed with nickel-chromium alloy electric heating wires 611 arranged in a reciprocating bending pattern (such as an S-shape or a serpentine shape). A blower 612 (which can supply air independently to each zone or branch off from a centralized air supply) is installed outside the furnace body 1. The blower 63 supplies air into the heating chamber 61 through a flexible ventilation pipe 613. The air flows over the incandescent electric heating wires 611 and is rapidly heated. Then, it is ejected at high speed from several exhaust pipes 614 distributed on the glass-facing side of the heating chamber 61, efficiently convectively heating the glass. Temperature sensing devices can also be installed inside the heating chamber 61 to monitor the heating temperature of the electric heating wires 611 in real time.

[0028] Among them, such as Figure 3 As shown, the exhaust pipe 614 outlet of the upper heating box 61 and the exhaust pipe 614 outlet of the lower heating box 61 are staggered with the axis of the second conveying roller 5 on the projection plane. The hot air mainly acts on the glass area between the two rollers, avoiding direct obstruction by the roller body.

[0029] The spacing adjustment mechanism 62 employs a servo electric cylinder (or a hydraulic cylinder), with its cylinder body fixed to the top or bottom wall of the furnace body 1. The end of the push rod is rigidly connected to the back of the heating box 61. Through commands from the PLC controller 2, the servo electric cylinder can precisely drive the heating box 61 to move closer to or further away from the glass, thereby steplessly adjusting the distance between the heating source and the glass surface, thus changing the heat flux density. A smaller distance increases the heat flux density and heating intensity; a larger distance weakens the heating intensity. The vent pipe 613 uses a metal flexible hose or a special rubber flexible hose to ensure that the air passage remains open during the movement of the heating box 61.

[0030] Within the working chamber of each heating section 11, a thermocouple or infrared thermometer is installed at the top and bottom as a temperature measuring element 7 (such as a thermocouple sensor or infrared temperature probe). Its detection end points near the surface of the glass plate to monitor the approximate temperature of the upper and lower surfaces of the glass in the section in real time.

[0031] The PLC controller 2 is connected via cables to the servo drivers of the electric heating wires 611 (via solid-state relays or power adjustment modules), blowers 612, and spacing adjustment mechanisms 62 within all heating sections 11, as well as the temperature sensing elements 7. The PLC contains pre-stored process recipes for various glass products, including target temperature-time curves for each heating section 11 and corresponding recommended heater spacing parameters. During operation, the PLC simultaneously receives feedback signals from all temperature sensing elements 7, compares them with the set values ​​of the current operating recipe, and independently adjusts the heating power of each heating section 11 (controlling the on / off state or power percentage of the electric heating wires 611) and the position of the upper and lower heating chambers 61 (via the spacing adjustment mechanism 62) using PID and other control algorithms. This achieves rapid and precise closed-loop control of the temperature of each section, as well as dynamic balance adjustment of the upper and lower heating intensity.

[0032] In addition, each heating section 11 has an independent inspection door 14 on the outer wall of the furnace body 1, which is equipped with a heat-resistant glass observation window and a reliable sealing and clamping device. The second conveyor roller 5 is made of heat-resistant alloy steel (such as 310S stainless steel), and its surface is plasma-sprayed with an alumina-based ceramic coating as an anti-adhesion layer to prevent high-temperature glass from sticking to it.

[0033] Working Principle: The process parameters of the glass to be tempered are input into the PLC controller 2, and the PLC retrieves the corresponding formula. The glass is fed into the furnace body 1 by the conveyor 3. When the glass enters a certain heating section 11, the temperature measuring element 7 of that section starts to work. The PLC independently controls the heating power and the position of the heating box 61 of that section according to the set curve and the measured temperature, ensuring that the glass undergoes a precisely set thermal process in that section. The coordinated work of each section makes the entire process of glass from preheating, rapid heating to uniform heat preservation completely controlled, and finally enters the subsequent cooling section at a uniform temperature that meets the process requirements, thereby obtaining a high-quality tempered glass product.

[0034] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A multi-stage independent precision temperature control heating system for a glass tempering furnace, comprising a furnace body (1), wherein a PLC controller (2) is provided on the outer wall of the furnace body (1), and conveyor frames (3) are provided on both the left and right sides of the furnace body (1), wherein a plurality of first conveyor rollers (4) are provided inside the conveyor frames (3), and a plurality of second conveyor rollers (5) are provided inside the furnace body (1), characterized in that: The furnace body (1) is divided into multiple independent heating sections (11) along the glass conveying direction. A refractory heat insulation plate (12) is provided between two adjacent heating sections (11), and the refractory heat insulation plate (12) is provided with a gap for glass to pass through. Each heating section (11) is independently provided with heating components (6) arranged above and below. The heating components (6) include a heating box (61) that can move relative to the inner wall of the furnace body (1) and a spacing adjustment mechanism (62) that drives the heating box (61) to move to adjust the distance between it and the glass plate surface. Each heating section (11) is provided with at least one pair of temperature measuring elements (7) extending into the working cavity of the section. The temperature measuring elements (7) are used to detect the approximate temperature of the upper and lower surfaces of the glass plate in real time. The PLC controller (2) is connected to the heating box (61), spacing adjustment mechanism (62) and temperature measuring element (7) of each heating section (11) respectively. Based on the pre-stored temperature setting curve of each section and the real-time feedback of the temperature measuring element (7), it independently controls the heating power and the action of the spacing adjustment mechanism (62) in each heating section (11).

2. The multi-stage independent precision temperature control heating system for a glass tempering furnace according to claim 1, characterized in that: The refractory insulation board (12) is an alumina ceramic fiber board fixed to the inner wall of the furnace body (1), and the side of the refractory insulation board (12) facing the heating section (11) is covered with a high-temperature reflective layer (13).

3. The multi-stage independent precision temperature control heating system for a glass tempering furnace according to claim 1, characterized in that: The heating box (61) is equipped with an electric heating wire (611), and a blower (612) is provided on the outside of the furnace body (1). The blower (63) supplies air to the heating box (61) through the ventilation pipe (613). Several exhaust pipes (614) are provided on the side of the heating box (61) near the glass plate.

4. The multi-stage independent precision temperature control heating system for a glass tempering furnace according to claim 3, characterized in that: The heating wire (611) is a nickel-chromium alloy heating wire, and the heating wire (611) is arranged in a reciprocating bending shape inside the heating box (61).

5. The multi-stage independent precision temperature control heating system for a glass tempering furnace according to claim 3, characterized in that: Within any of the heating sections (11), the exhaust pipe (614) outlet of the upper heating box (61) and the exhaust pipe (614) outlet of the lower heating box (61) are arranged alternately with the axis of the second conveying roller (5) on a projection plane perpendicular to the glass conveying direction.

6. The multi-stage independent precision temperature control heating system for a glass tempering furnace according to claim 3, characterized in that: The spacing adjustment mechanism (62) is a hydraulic cylinder or a servo electric cylinder. Its cylinder body is fixed to the inner wall of the furnace body (1), and the end of its piston rod / push rod is rigidly connected to the corresponding heating box (61). The vent pipe (613) is a flexible telescopic pipe.

7. The multi-stage independent precision temperature control heating system for a glass tempering furnace according to claim 1, characterized in that: Along the glass conveying direction, the first heating section (11) is configured as a preheating zone, one or more heating sections (11) in the middle are configured as main heating zones, and the heating section (11) at the end is configured as a heat equalization and heat preservation zone. The target temperature curve of each heating section (11) is independently set and adjusted by the PLC controller (2).

8. The multi-stage independent precision temperature control heating system for a glass tempering furnace according to claim 1, characterized in that: The second conveying roller (5) is made of heat-resistant alloy steel and the surface of the second conveying roller (5) is coated with an anti-adhesion ceramic coating.

9. The multi-stage independent precision temperature control heating system for a glass tempering furnace according to claim 1, characterized in that: Each heating section (11) has an independent maintenance door (14) with an observation window and a sealing structure on the outer wall of the furnace body (1).

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