Heating device of hot air oven

Abstract

The utility model provides a hot air oven heating device which comprises an installation fixing plate, a box body fixed on the installation fixing plate, a U-shaped electric heating resistance wire, a thermocouple, an air supply pipe, air nozzle units, an electric heating resistance wire connecting piece and a wiring terminal, the air supply pipe extends along the length direction of the electric heating resistance wire, and a plurality of groups of air nozzle units are arranged on the surface of the air supply pipe in a linear array mode. Each group of tuyeres are distributed in a radial shape, the U-shaped electric heating resistance wires are connected with three-phase alternating current in a grouping and triangular mode through iron-chromium-aluminum alloy, the tuyeres are provided with conical openings and are arranged in a hexagonal and annular mode, the air supply pipes are connected with the adjustable air supply connectors, and the thermocouples are distributed in a regular triangle mode to monitor temperature. The device realizes uniform distribution of hot air and efficient heat conduction, has the advantages of high temperature corrosion resistance, accurate temperature control, high energy utilization rate and strong equipment stability, and effectively solves the problems of non-uniform heating, high energy consumption and easy damage of the furnace body of the traditional oven.

Description

Technical Field

[0001] This utility model relates to the field of industrial heating, and in particular to a hot air oven heating device. Background Technology

[0002] Hot air furnace heating devices are used for drying the refractory lining materials of large metallurgical furnaces after construction or major repairs. This prevents the furnace body from cracking or deforming due to rapid heating, excessive moisture evaporation, and volume expansion before production. The performance of these devices directly affects the structural safety and service life of the furnace. Traditional hot air furnace heating devices generally use an exposed resistance wire direct heating structure. The resistance wire is connected to a three-phase AC power supply, and heat is conducted through thermal radiation. When the resistance wire reaches a certain temperature, compressed air is introduced through the furnace body's air vents, allowing the heat to dissipate within the furnace cavity.

[0003] In actual use, the high-temperature area generated by the resistance wire is concentrated when it is working, resulting in a significant temperature gradient inside the sealed furnace cavity. The heat is unevenly distributed in the furnace cavity, the heat conduction speed is slow, the furnace baking time is long, resulting in a large amount of energy waste. It can also cause stress cracks caused by uneven heating of the furnace bricks, posing a safety hazard of furnace brick falling off and breaking, reducing the service life of the furnace bricks, and in severe cases, even causing deformation of the furnace body steel structure. Utility Model Content

[0004] In view of the problems existing in the prior art, this utility model provides a hot air oven heating device, which aims to improve the heat conduction efficiency and make the heat distribution uniform.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a hot air oven heating device, characterized in that it includes a mounting plate, a housing mounted above the mounting plate, multiple sets of U-shaped heating elements, an air supply assembly, an electrical connection assembly, a temperature detection unit, and a control unit; the U-shaped heating elements are arranged in a multi-layered annular array along the mounting plate; the air supply assembly includes an air supply pipe and multiple sets of nozzle units, one end of the air supply pipe is connected to the air supply interface inside the housing, and the other end extends through the mounting plate along the length of the U-shaped heating elements, and... The air supply duct is located laterally at the center of the heating element ring; the multiple sets of nozzle units are linearly arrayed at equal intervals along the length of the air supply duct, each set of nozzle units includes multiple nozzles evenly distributed radially around the air supply duct, wherein the air inlet end of each nozzle is connected to the air supply duct, and the air outlet end of each nozzle has a tapered air outlet section; the electrical connection assembly includes a terminal block for an external power supply and a heating element connecting piece, the electrical connection assembly is fixed on a mounting plate and placed inside the housing; the control unit controls the number of heating element sets to be engaged based on the temperature detection unit.

[0006] Furthermore, the nozzle also has a straight air inlet, and the straight air inlets of each nozzle have equal inner diameter and axial length, and the opening size of the conical air outlet is the same.

[0007] Furthermore, the air supply interface has a built-in threaded connection structure with adjustable opening.

[0008] Furthermore, each group of heating wires in the U-shaped heating wires is connected end to end in a triangular structure and connected to a three-phase AC power supply through a terminal block.

[0009] Furthermore, the temperature detection unit includes three thermocouples, which are arranged in an equilateral triangle on the edge of the mounting plate.

[0010] Furthermore, the material of the wiring terminal and the heating element connecting piece is T2 copper.

[0011] Furthermore, the U-shaped heating wire is made of an iron-chromium-aluminum alloy.

[0012] Furthermore, the mounting plate, housing, air duct, nozzle, and air outlet are made of 304 stainless steel.

[0013] Compared with the prior art, the present invention has the following advantages: When the electric heating resistance wire is heated to a certain temperature, compressed air is sent in through the air duct, and the heat is quickly and evenly distributed in the furnace cavity, so that the furnace cavity is heated evenly. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the heating device of this utility model;

[0015] Figure 2 This is a schematic diagram of the nozzle unit structure of this utility model;

[0016] Figure 3 This is a schematic diagram of the annular arrangement of the heating resistance wires of this utility model;

[0017] Explanation of reference numerals in the attached drawings: 1. Housing; 2. Terminal block; 3. Heating resistance wire connecting piece; 4. Thermocouple; 5. Mounting plate; 6. U-shaped heating resistance wire; 7. Air supply interface; 8. Nozzle unit; 8-1. Nozzle; 8-2. Conical air outlet; 9. Air supply duct. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] The hot air oven heating device of this utility model mainly consists of a mounting plate 5 as the supporting base, on which a housing 1 is welded and fixed. Both are made of 304 stainless steel to improve the overall high temperature resistance and structural stability. A U-shaped heating element 6 is arranged in multiple rings along the surface of the mounting plate 5, made of iron-chromium-aluminum alloy. 72 heating elements, each 3m long, are divided into three groups of 24, forming a triangular connection structure through heating element connecting pieces 3. This structure, along with the terminal block 2, connects to a three-phase power supply, effectively balancing the current load of each phase. The terminal block 2 and the heating element connecting pieces 3 are made of T2 copper. One end of the air supply duct 9 connects to the air supply interface 7 inside the housing 1. The air supply interface 7 has a built-in threaded adjustment mechanism, allowing precise control of the air intake by adjusting the opening through a screwing operation. The other end of the air supply duct 9 extends along the length of the U-shaped heating element 6. The air supply duct 9 is made of 304 stainless steel with an inner diameter of 30mm and a length of 3.1 meters. Ten nozzle units 8 are linearly arrayed at equal intervals on the surface of the air supply duct. Each group of nozzle units 8 has 6 nozzles 8-1 fixed in a radial arrangement. Each nozzle 8-1 has an inner diameter of 10mm, an axial length of 20mm, and a tapered structure with a 5mm tapered opening at the air outlet. Combined with the air supply duct 9 with an inner diameter of 30mm, it forms a gradient air pressure, which causes the compressed air to be accelerated and ejected from the 60 nozzles 8-1 to form a high-speed turbulent flow, and evenly diffuses the heat generated by the electric heating wire 6 into the furnace cavity.

[0020] Three thermocouples 4 arranged in an equilateral triangle are installed on the edge area of ​​the mounting plate 5. One end of each thermocouple 4 extends into the hot air oven, while the other end is located outside the chamber, to monitor the temperature distribution inside the oven in real time. Based on the real-time monitoring values ​​of the thermocouples 4, the control unit controls the number of U-shaped heating wires 6 engaged, and achieves stepped heating by controlling the start and stop combinations of the three sets of U-shaped heating wires 6 in groups.

[0021] When using the heating device of this utility model, first connect the three-phase 380V power supply to terminal 2, and put all three sets of U-shaped resistance wires into the circuit. Monitor the temperature inside the furnace as it rises from room temperature to the starting temperature of the furnace baking process curve. Introduce compressed air to control the pressure at about 0.45MPa. According to the furnace baking process curve, the temperature controller automatically engages and disengages the resistance wires. When the temperature reaches the first stage of the furnace baking process curve, adjust the opening of the air supply port 7 to reduce the compressed air pressure to about 0.4MPa and maintain it for a certain period of time. When the temperature reaches the second stage of the furnace baking curve, the temperature controller controls the engagement and disengagement of the resistance wires, adjusts the opening of the air supply port 7 to reduce the compressed air pressure to about 0.35MPa and maintains it for a certain period of time until the furnace baking operation is completed.

[0022] This invention's heating device significantly improves the uniformity of hot air diffusion through the synergistic effect of multiple radially arranged radially arrayed nozzles with conical openings and multi-layered, annularly arranged U-shaped heating wires. The 304 stainless steel composite structure maintains a stable shape under high-temperature conditions, and the adjustable air supply mechanism and grouped temperature control strategy reduce energy consumption by approximately 40%. This design effectively solves the problems of heat accumulation and uneven heating of furnace bricks in traditional furnace devices, reducing thermal stress on the furnace structure by more than 60% and significantly extending the service life of the furnace bricks.

[0023] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or substitute or modify some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A hot air oven heating device, characterized in that, Includes mounting plate (5), housing (1) mounted on top of mounting plate (5), multiple sets of U-shaped heating wires (6), air supply assembly, electrical connection assembly, temperature detection unit and control unit; The U-shaped heating wire (6) is arranged in a multi-layered ring array along the mounting plate (5); The air supply assembly includes an air supply pipe (9) and multiple sets of nozzle units (8). One end of the air supply pipe (9) is connected to the air supply interface (7) inside the housing (1), and the other end passes through the mounting plate (5) and extends along the length of the U-shaped heating wire (6) and is laterally located at the center of the heating wire ring. The multiple sets of nozzle units (8) are arranged in a linear array at equal intervals along the length of the air supply pipe (9). Each set of nozzle units includes multiple nozzles (8-1) that are evenly distributed radially around the air supply pipe (9). The air inlet end of each nozzle is connected to the air supply pipe (9), and the air outlet end of each nozzle has a tapered air outlet (8-2). The electrical connection assembly includes an external power supply terminal (2) and an electric heating wire connecting piece (4). The electrical connection assembly is fixed on the mounting plate (5) and placed inside the housing (1).

2. The hot air oven heating device according to claim 1, characterized in that, The air nozzle (8-1) also has a straight air inlet, and the straight air inlets of each air nozzle have equal inner diameter and axial length, and the opening size of the conical air outlet (8-2) is the same.

3. The hot air oven heating device according to claim 1, characterized in that, The air supply interface (7) has a built-in threaded connection structure with adjustable opening.

4. The hot air oven heating device according to claim 1, characterized in that, Each group of heating wires in the U-shaped heating wire (6) is connected end to end in a delta connection and connected to a three-phase AC power supply through the terminal block (2).

5. The hot air oven heating device according to claim 1, characterized in that, The temperature detection unit includes three thermocouples (3), which are arranged in an equilateral triangle on the edge of the mounting plate (5).

6. The hot air oven heating device according to claim 1, characterized in that, The terminal block (2) and the heating element connecting piece (4) are made of T2 copper.

7. The hot air oven heating device according to claim 1, characterized in that, The U-shaped heating wire (6) is made of iron-chromium-aluminum alloy.

8. The hot air oven heating device according to claim 1, characterized in that, The mounting plate (5), housing (1), air supply pipe (9), nozzle (8-1), and air supply interface (7) are made of 304 stainless steel.

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