Continuous heating kiln
By combining gas and electric heating systems, low-cost, rapid heating and high-precision temperature control of continuous heating kilns are achieved, overcoming the shortcomings of existing electric and natural gas heating methods and improving the thermal efficiency of the kiln and product quality.
Patent Information
- Application Number
- CN202423012640.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-06
- Publication Date
- 2026-01-09
- Estimated Expiration
- 2034-12-06
AI Technical Summary
Existing continuous heating kilns suffer from problems such as high cost, insufficient temperature control precision, and poor product consistency in both electric and natural gas heating methods. They are particularly inefficient and wasteful of energy during the sintering of high-temperature sensitive materials.
By combining a gas combustion system and an electric heating system, the gas provides the base temperature, and the electric heating system is used for compensation and regulation to achieve precise temperature control and uniformity. The electric heating elements and gas pipelines are arranged alternately, and temperature sensors and controllers are used for real-time regulation.
It achieves low-cost, rapid heating and high-precision temperature control, reducing production costs, extending the life of electric heating elements, and improving product quality consistency and production efficiency.
Smart Images
Figure CN223783333U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of heat treatment / material sintering equipment, and particularly relates to a heating kiln. Background Technology
[0002] For continuous heating kilns, taking roller kilns as an example, heating elements pass horizontally through the furnace chamber from the top and bottom, respectively, with the material and the rollers holding the material placed between the upper and lower heating elements. Electric heating is a widely used heating method for continuous heating kilns. Electric heating kilns can precisely and rapidly control the heating temperature, resulting in good sintering effects, especially for temperature-sensitive materials, high yield, and minimal environmental impact. They can be widely used in powder metallurgy, petrochemicals, electronics, light industry, daily chemicals, and pharmaceuticals.
[0003] Before materials enter the kiln, the kiln must be heated to the required temperature. While electrically heated roller kilns can precisely control the heating temperature, the cost of electricity is high for production processes requiring kiln preheating, long-term continuous operation, and heat preservation during shutdowns, especially in developed regions where industrial electricity is expensive. Furthermore, continuous heating kilns are generally large in size, resulting in significant heat loss, making electricity costs a major component of their product costs. Large-scale manufacturers of new energy materials sintering and heat treatment are typically major energy consumers in their respective regions. In the energy classification system, electricity is the highest quality form of energy with the highest energy density; directly converting it into heat for use would be a waste of this high-quality energy source.
[0004] Using natural gas to heat kilns offers rapid heating and high efficiency, and costs approximately 40% of electric heating for the same calorific value. Although current natural gas combustion heating technology is relatively mature, it still cannot meet the requirements in applications where high temperature control precision is needed. For heat treatment or sintering of temperature-sensitive materials, it can lead to problems such as poor product consistency and low production efficiency.
[0005] In view of the problems existing in the current kiln heating technologies of electric heating and natural gas heating, there is a need for a heating kiln that can make full use of the advantages of each and effectively solve these problems at the same time. Utility Model Content
[0006] The technical problem to be solved by this utility model is to overcome the deficiencies and defects mentioned in the background art above, and to provide a continuous heating kiln with fast heating speed, high efficiency, uniform temperature inside the furnace, high temperature control accuracy and low cost.
[0007] To solve the above-mentioned technical problems, the technical solution proposed by this utility model is as follows:
[0008] A continuous heating kiln includes a furnace body, a gas combustion system, and an electric heating system. The gas combustion system includes hot gas heating pipes, specifically a first hot gas pipe and a second hot gas pipe. The first hot gas pipe is located on the upper and lower sides of the furnace body, and the second hot gas pipe is located on the left and right sides of the furnace body along the kiln's conveying direction. The electric heating system includes electric heating elements for heating compensation and temperature adjustment, located on the upper and lower sides and / or the left and right sides of the furnace body. The gas combustion system first provides a base temperature to the furnace chamber through the hot gas heating pipes. After each temperature zone reaches the base temperature, the electric heating system is activated to perform heating compensation and adjustment for each temperature zone to meet process temperature requirements and temperature uniformity requirements.
[0009] In the aforementioned continuous heating kiln, preferably, the first hot gas pipe and the electric heating element are arranged alternately and evenly at intervals. This arrangement ensures that the first hot gas pipe and the electric heating element are evenly distributed throughout the kiln's heating area, thereby achieving a more uniform heating effect. Secondly, it allows for more efficient utilization of the heat generated by the electric heating element, reducing heat waste and improving overall thermal efficiency. Furthermore, it helps prevent localized overheating that could damage materials or affect product quality, ensuring the stability and safety of the heating process.
[0010] In the aforementioned continuous heating kiln, preferably, the gas combustion system further includes an inlet main pipe for conveying hot gas to the hot gas heating pipe and an outlet main pipe for outputting and reheating the hot gas from the hot gas heating pipe, wherein the inlet main pipe and the outlet main pipe are located outside the kiln body. This arrangement facilitates the maintenance and repair of the pipeline, reduces the risks and complexity of operating inside the kiln body, and helps to quickly locate and handle leaks or other problems, thereby improving the overall safety of the kiln.
[0011] In the aforementioned continuous heating kiln, preferably, an inlet main pipe and an outlet main pipe are provided on each of the left and right sides of the kiln body, and adjacent hot gas heating pipes are connected to the inlet main pipe and the outlet main pipe, respectively. This arrangement allows the gas flow directions of two adjacent hot gas heating pipes to be opposite, enabling better and more precise temperature regulation within the kiln body and ensuring temperature uniformity.
[0012] In the aforementioned continuous heating kiln, preferably, the electric heating system further includes several sections of heating resistance wire wound at intervals around the air inlet pipe. This arrangement allows for segmented and precise auxiliary heating of the hot gas entering the furnace, heating areas requiring temperature compensation to ensure that the temperature inside the furnace meets requirements and that temperature uniformity is maintained.
[0013] In the aforementioned continuous heating kiln, preferably, the electric heating system further includes a temperature sensor for collecting temperature information of various areas within the kiln. The temperature sensor is electrically connected to the electric heating element and the heating resistance wire via a controller. The temperature sensor can monitor the kiln temperature in real time, and the controller adjusts the operating state of the electric heating element and the heating resistance wire based on this data, achieving precise temperature control and avoiding unnecessary energy consumption, thus achieving energy savings.
[0014] In the aforementioned continuous heating kiln, preferably, the electric heating element is a continuous heating rod. Using a continuous heating rod provides a wide heating range, fast heating speed, and more uniform temperature distribution within the furnace.
[0015] In the aforementioned continuous heating kiln, preferably, the furnace body includes a high-temperature zone and a low-temperature zone, and the gas combustion system is located in the high-temperature zone. By placing the gas combustion system in the high-temperature zone, where the kiln temperature is high and the heat demand is large, the hot gas heated in the high-temperature zone can be transported to the low-temperature zone, where the heat demand is small, through flow within the furnace or by setting up hot gas channels, thus achieving tiered utilization of heat.
[0016] In the aforementioned continuous heating kiln, preferably, the furnace body includes a furnace shell and a refractory layer, the refractory layer being attached to the inner wall of the furnace shell, and the hot gas heating pipes being disposed within the refractory layer. This arrangement can utilize space more effectively, especially in space-constrained situations, maximizing the utilization efficiency of the area, and the refractory layer has a certain temperature-uniforming effect, further improving the temperature uniformity within the furnace.
[0017] In the aforementioned continuous heating kiln, preferably, burners or nozzles with control valves are spaced apart on the hot gas heating pipe. This arrangement allows the furnace to quickly reach a high temperature in a short time. Furthermore, if the material being heated or sintered has high atmospheric requirements and cannot be directly heated by combustion or hot gas, the burners or nozzles can be shut off by the control valves, and indirect heating can be achieved through the hot gas heating pipe, making it widely applicable.
[0018] Compared with the prior art, the advantages of this utility model are:
[0019] This invention provides a base temperature for kiln heating by setting up a gas combustion system, and then compensates for and precisely controls the kiln temperature by setting up an electric heating system. This achieves both low-cost rapid heating in the kiln and precise temperature control, significantly reducing production costs and extending the service life of the electric heating components. It has the advantages of simple control, good control effect, high temperature control accuracy, low cost, easy implementation, and easy modification of existing equipment. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the longitudinal section of the kiln in Example 1;
[0022] Figure 2 This is a schematic diagram of the transverse cross-section of the kiln in Example 1;
[0023] Figure 3 This is a top view cross-section diagram of the kiln in Example 1;
[0024] Figure 4 This is a partial cross-sectional view of the kiln air inlet main pipe in Example 1.
[0025] Figure 5 This is a schematic diagram of the longitudinal section of the kiln in Example 2;
[0026] Figure 6 This is a schematic diagram of the transverse cross-section of the kiln in Example 2.
[0027] Legend
[0028] 1. Furnace body; 2. First hot gas pipe; 3. Second hot gas pipe; 4. Inlet main pipe; 5. Outlet main pipe; 6. Electric heating element; 7. Heating resistance wire; 8. Burner. Detailed Implementation
[0029] To facilitate understanding of this utility model, it will be described more comprehensively and in detail below with reference to the accompanying drawings and preferred embodiments. However, the scope of protection of this utility model is not limited to the following specific embodiments.
[0030] It should be noted that when a component is described as being "fixed to, attached to, connected to or connected to" another component, it can be directly fixed to, attached to, connected to or connected to the other component, or it can be indirectly fixed to, attached to, connected to or connected to the other component through other intermediate connectors.
[0031] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of protection of this invention.
[0032] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.
[0033] Example 1:
[0034] like Figures 1 to 4 As shown, the continuous heating kiln of this embodiment includes a kiln body 1, a gas combustion system, and an electric heating system. The gas combustion system includes hot gas heating pipes, which include a first hot gas pipe 2 and a second hot gas pipe 3. The first hot gas pipe 2 is disposed on the upper and lower sides inside the kiln body 1, and the second hot gas pipe 3 is disposed on the left and right sides inside the kiln body 1 along the kiln conveying direction. The electric heating system includes electric heating elements 6 for heating compensation and temperature adjustment, which are disposed on the upper and lower sides inside the kiln body 1.
[0035] In this embodiment, the first hot air pipe 2 and the electric heating element 6 are arranged alternately at uniform intervals.
[0036] like Figure 3 As shown, in this embodiment, the gas combustion system further includes an inlet main pipe 4 for conveying hot gas to the hot gas heating pipe and an outlet main pipe 5 for outputting and reheating the hot gas from the hot gas heating pipe. The inlet main pipe 4 and the outlet main pipe 5 are located on the outside of the furnace body 1. The exposed portion on the outside of the furnace body 1 can be covered with heat insulation material to increase the efficiency of heat energy utilization.
[0037] In this embodiment, an air inlet pipe 4 and an air outlet pipe 5 are provided on the left and right sides of the furnace body 1, respectively, and adjacent hot gas heating pipes are connected to the air inlet pipe 4 and the air outlet pipe 5.
[0038] like Figure 4 As shown, in this embodiment, the electric heating system also includes several sections of heating resistance wire 7 wound at intervals around the intake manifold 4. The heating resistance wire 7 can be a spiral heating element wound around the inner wall of the intake manifold 4. This arrangement can avoid losses related to external heat transfer and is more energy-efficient.
[0039] In this embodiment, the electric heating system also includes a temperature sensor for collecting temperature information of each area inside the furnace body 1. The temperature sensor is electrically connected to the electric heating element 6 and the heating resistance wire 7 through the controller.
[0040] In this embodiment, the electric heating element 6 is a continuous heating rod. Each continuous heating rod and the hollow hot gas heating pipe can be installed in a protective sleeve that runs through the furnace to prevent the corrosive atmosphere inside the furnace from damaging the continuous heating rod and the hot gas heating pipe. The material of the electric heating element 6 can be selected from silicon carbide rods, silicon molybdenum rods, resistance wires, resistance strips, heating tubes, etc., depending on the temperature, atmosphere, installation method, etc.
[0041] In this embodiment, the furnace body 1 includes a high-temperature zone and a low-temperature zone, and the gas combustion system is located in the high-temperature zone.
[0042] In this embodiment, the furnace body 1 includes a furnace shell and a refractory layer. The refractory layer is attached to the inner wall of the furnace shell, and the hot gas heating pipe is disposed within the refractory layer. In other embodiments, the hot gas heating pipe may be configured to pass directly through the furnace chamber or be partially exposed within the furnace chamber, as needed.
[0043] In this embodiment, the specific steps are as follows: First, the furnace is provided with a base temperature through the gas combustion system. For example, if a certain temperature zone requires 1000℃, it is first heated to 800℃ by gas and maintained at that temperature. This 800℃ is the base temperature of that temperature zone. Natural gas is used to heat nitrogen through the gas inlet pipe 4, and then the furnace is heated through the hot gas heating pipe. Natural gas heats nitrogen faster, which can bring the furnace to the base temperature range as soon as possible. After each temperature zone reaches the base temperature, the electric heating system is started to perform heating compensation adjustment for each temperature zone. First, the temperature is increased to the required temperature through the continuous heating rod, and then the heating resistance wire 7 is controlled to assist in heating. At the same time, the heating temperature of the continuous heating rod and the auxiliary heating resistance wire 7 is controlled by the temperature information fed back by the temperature sensor in the furnace, so that the furnace meets the required temperature.
[0044] In this embodiment, the hot gas heating pipe is made of metal; in other embodiments, ceramic materials with good thermal conductivity can be used. The hot gas passing through the gas combustion system can be the combustion product of dried natural gas, or hot gas heated by other low-cost fuels.
[0045] Example 2:
[0046] like Figure 5 and Figure 6 As shown, the continuous heating kiln in this embodiment is basically the same as that in embodiment 1, except that burners 8 with control valves are spaced apart on the hot gas heating pipe.
[0047] In other embodiments, nozzles with control valves may be spaced apart on the hot gas heating pipe, or burners 8 may be spaced apart from nozzles.
Claims
1. A continuous heating kiln, comprising a furnace body (1), characterized in that, It also includes a gas combustion system and an electric heating system. The gas combustion system includes a hot gas heating pipe, which includes a first hot gas pipe (2) and a second hot gas pipe (3). The first hot gas pipe (2) is located on the upper and lower sides of the furnace body (1), and the second hot gas pipe (3) is located on the left and right sides of the furnace body (1) along the kiln conveying direction. The electric heating system includes an electric heating element (6) for heating compensation and temperature adjustment. The electric heating element (6) is located on the upper and lower sides and / or the left and right sides of the furnace body (1).
2. The continuous heating kiln according to claim 1, characterized in that, The first hot air pipe (2) and the electric heating element (6) are arranged alternately at uniform intervals.
3. The continuous heating kiln according to claim 1, characterized in that, The gas combustion system further includes an inlet main pipe (4) for conveying hot gas to the hot gas heating pipe and an outlet main pipe (5) for outputting and reheating the hot gas from the hot gas heating pipe. The inlet main pipe (4) and the outlet main pipe (5) are located outside the furnace body (1).
4. The continuous heating kiln according to claim 3, characterized in that, An air inlet pipe (4) and an air outlet pipe (5) are provided on the left and right sides of the furnace body (1), respectively, and the adjacent hot gas heating pipes are connected to the air inlet pipe (4) and the air outlet pipe (5).
5. The continuous heating kiln according to claim 3, characterized in that, The electric heating system also includes several sections of heating resistance wire (7) wound at intervals on the intake manifold (4).
6. The continuous heating kiln according to claim 5, characterized in that, The electric heating system also includes a temperature sensor for collecting temperature information of each area inside the furnace body (1). The temperature sensor is electrically connected to the electric heating element (6) and the heating resistance wire (7) through a controller.
7. The continuous heating kiln according to any one of claims 1-6, characterized in that, The electric heating element (6) is a continuous heating rod.
8. The continuous heating kiln according to any one of claims 1-6, characterized in that, The furnace body (1) includes a high-temperature zone and a low-temperature zone, and the gas combustion system is located in the high-temperature zone.
9. The continuous heating kiln according to any one of claims 1-6, characterized in that, The furnace body (1) includes a furnace shell and a refractory layer. The refractory layer is attached to the inner wall of the furnace shell, and the hot gas heating pipe is disposed in the refractory layer.
10. The continuous heating kiln according to any one of claims 1-6, characterized in that, The hot gas heating pipe is provided with burners (8) or nozzles with control valves at intervals.