Cover type annealing furnace

Abstract

The invention relates to the technical field of annealing furnaces, and discloses a bell-type annealing furnace which comprises a base, a furnace body and a furnace cover, an inner cover; a combustion cavity is formed between the outer cover and the inner cover, and a heat exchanger communicated with the combustion cavity is arranged on the outer cover; the smoke exhaust pipe is communicated with the inner cavity of the heat exchanger, and an opening adjusting valve is arranged on the smoke exhaust pipe; one end of the combustion-supporting air inlet pipe is communicated with an air outlet of the fan, and the other end of the combustion-supporting air inlet pipe penetrates through the heat exchanger and is communicated with the burner through a pressure-stabilizing pipe; the pressurizing pipe is communicated with the area, penetrating out of the heat exchanger, of the combustion-supporting air inlet pipe and the pressure stabilizing pipe, and the combustion-supporting air inlet pipe is provided with a one-way valve corresponding to the pressurizing pipe; and the compressed air pipe is communicated with the pressure stabilizing pipe. According to the bell-type annealing furnace provided by the invention, the opening adjusting valve is arranged, so that the air pressure in the combustion cavity is kept to be micro-positive pressure, and the air pressure in the combustion cavity is prevented from being too low or too high; and by arranging the pressurizing pipe and the compressed air pipe, the air pressure of the combustion-supporting air in the pressure stabilizing pipe is increased, and therefore the oxygen content in the unit volume is increased.

Description

Technical Field

[0001] The invention relates to the technical field of annealing furnaces, and in particular to a bell-type annealing furnace. Background Art

[0002] Cold rolling is a commonly used metal processing technology. Taking cold-rolled steel coils as an example, after cold rolling, the hardness of the steel coils increases and the plasticity decreases, which affects the processability and performance of the steel coils. Therefore, the steel coils need to be processed using an annealing process. A hood annealing furnace is an industrial equipment used for heat treatment of metal materials. Its heating medium is generally a gas fuel, such as natural gas or coke oven gas, and the combustion air is directly extracted from the hood annealing furnace workshop by a fan. When the steel coils are annealed, the steel coils are placed in the inner hood of the hood annealing furnace in a stacked form. Chinese Patent Publication No.: CN112460987A discloses a hood of a hood furnace and an operating method. By setting a heat exchanger, the high-temperature flue gas generated after combustion enters the heat exchanger through the exhaust pipe, so that the heat exchanger uses the heat of the high-temperature flue gas to preheat the cold combustion air. However, the temperature of the preheated combustion air increases, resulting in a decrease in air density and a decrease in the oxygen content per unit volume of the combustion air. When the temperature of the combustion air is too high, the oxygen content per unit volume of the combustion air is less, which affects the combustion effect of the gas fuel and thus the annealing effect of the metal material. In addition, the pressure in the current hood annealing furnace is uncontrollable, and there is a problem of incomplete combustion due to too low pressure or shortened equipment service life due to too high pressure. Summary of the invention

[0003] In view of this, the present invention provides a hood-type annealing furnace to solve the problem that when the temperature of the combustion air is too high, the oxygen content per unit volume of the combustion air is too low, which affects the combustion effect of the gas fuel; and the current hood-type annealing furnace has an uncontrollable pressure inside the furnace, and there is a problem that the pressure is too low resulting in incomplete combustion or the pressure is too high resulting in a shortened service life of the equipment.

[0004] The present invention provides a bell-type annealing furnace, comprising: Base; An inner cover is arranged on the base, and the interior of the inner cover is used for placing the steel coil; The outer cover is sleeved on the outside of the inner cover and a combustion chamber is formed between the outer cover and the inner cover. A heat exchanger is arranged on the outer cover, and the inner chamber of the heat exchanger is connected with the combustion chamber. The smoke exhaust pipe is connected to the inner cavity of the heat exchanger, and an opening regulating valve is arranged on the smoke exhaust pipe to keep the gas pressure in the combustion chamber at a slightly positive pressure; The combustion air inlet pipe has one end connected to the air outlet of the first fan, and the other end passes through the heat exchanger and is connected to the burner through the voltage regulator tube; The pressurized pipe has one end connected to the area where the combustion air inlet pipe passes through the heat exchanger, and the other end connected to the pressure-stabilizing pipe. A booster pump is provided on the pressurized pipe, and a one-way valve is provided on the combustion air inlet pipe corresponding to the pressurized pipe; The compressed air pipe is connected with the pressure-stabilizing tube to be suitable for introducing compressed air at room temperature into the pressure-stabilizing tank, satisfying P4=P3+(T1-T0) / k, wherein 0.1℃ / pa≤k≤0.2℃ / pa, T1-T0≥0, P3 is the air pressure before the combustion air is pressurized, and its unit is pa; P4 is the air pressure in the pressure-stabilizing tube, and its unit is pa; T0 is the preset temperature after the combustion air is preheated, and its unit is ℃; T1 is the actual temperature of the combustion air after being preheated by the heat exchanger, and its unit is ℃.

[0005] Beneficial effects: By setting the opening regulating valve to adjust the speed of high-temperature flue gas being discharged through the exhaust pipe, the gas pressure in the combustion chamber is kept at a slightly positive pressure to avoid the gas pressure in the combustion chamber being too low or too high; and by setting the pressurizing pipe and the compressed air pipe to increase the gas pressure of the combustion air in the pressure-stabilizing pipe, the oxygen content per unit volume is increased, which is beneficial to ensure the combustion effect of the gas fuel. The gas pressure in the pressure-stabilizing pipe satisfies P4=P3+(T1-T0) / k, so that the degree of gas pressurization is positively correlated with the degree by which the temperature of the combustion air exceeds the maximum temperature, and the gas pressurization range is limited to avoid the gas pressure in the pressure-stabilizing pipe being too high, and then the high temperature of the combustion air is superimposed and then deflagration occurs in the combustion chamber.

[0006] In an optional implementation, the gas pressure in the combustion chamber is defined as P1, and the gas pressure of the surrounding environment of the bell-type annealing furnace is defined as P2, wherein 50pa≤P1-P2≤80pa.

[0007] In an optional embodiment, an air pressure sensor is provided on the outer cover, and the air pressure sensor is suitable for detecting the air pressure in the combustion chamber. The opening regulating valve is electrically connected to the air pressure sensor so as to adjust the opening of the opening regulating valve according to the air pressure in the combustion chamber detected by the air pressure sensor.

[0008] Beneficial effect: It is suitable for adjusting the opening of the opening regulating valve according to the air pressure detected by the air pressure sensor, so as to adjust the smoke exhaust speed so that the air pressure in the combustion chamber remains basically constant or within a preset range, which is conducive to improving the degree of automation.

[0009] In an optional embodiment, a fourth flow regulating valve is provided on the compressed air pipe; a first temperature sensor is provided in the area where the combustion air inlet pipe passes through the heat exchanger, and the first temperature sensor is suitable for detecting the temperature of the preheated combustion air, and the first temperature sensor is electrically connected to the boost pump and the fourth flow regulating valve.

[0010] In an optional embodiment, the bell annealing furnace further comprises: The sleeve is sleeved on the outside of the voltage regulator tube and forms an air flow channel between the sleeve and the voltage regulator tube; A cold air pipe is connected to the air flow channel to be suitable for introducing cooling gas into the air flow channel, and a first flow regulating valve is arranged on the cold air pipe; The hot air pipe has one end connected to the combustion chamber and the other end connected to the air flow channel. The hot air pipe is provided with a second flow regulating valve.

[0011] Beneficial effect: By adjusting the opening sizes of the first flow regulating valve and the second flow regulating valve to change the gas temperature in the airflow channel, the combustion air in the pressure regulating tube is cooled or heated to reduce the temperature fluctuation range of the combustion air entering the burner, which is beneficial to ensure the combustion stability of the gas fuel.

[0012] In an optional embodiment, the hood-type annealing furnace also includes an air inlet pipe, one end of which is connected to the voltage-stabilizing tube, and the other end is connected to the burner, and a third flow regulating valve is arranged on the air inlet pipe; the hood-type annealing furnace also includes a gas inlet pipe, which is connected to the burner so as to be suitable for introducing gas fuel into the burner, and a proportional valve is arranged on the gas inlet pipe to control the amount of gas fuel entering the burner.

[0013] Beneficial effects: The third flow regulating valve is used to control the amount of combustion air entering the burner, and the proportional valve is set to control the ratio of gas fuel and combustion air to ensure normal combustion of the gas fuel.

[0014] In an optional embodiment, there are multiple burners, each burner is respectively connected to at least one air inlet pipe and at least one gas inlet pipe, and the multiple burners are distributed at intervals along the circumference of the outer cover.

[0015] Beneficial effect: By arranging a plurality of burners distributed at intervals, the uniformity of heating the inner cover can be improved.

[0016] In an optional embodiment, the hood-type annealing furnace further includes a gas main pipe, a plurality of gas inlet pipes are respectively connected to the gas main pipe, and a pressure-stabilizing valve is provided on the gas main pipe.

[0017] In one embodiment, the outside of the sleeve is wrapped with thermal insulation wool; and / or, the combustion air inlet pipe is wrapped with heat insulating wool on the outside; and / or, the outside of the air inlet pipe is wrapped with heat insulation wool; and / or, the exterior of the outer cover is wrapped with thermal insulation wool; And / or, the exterior of the smoke exhaust pipe is wrapped with heat insulation cotton.

[0018] Beneficial effect: By arranging heat insulation cotton on the outside of the above-mentioned components, the heat preservation and heat insulation effect of the bell-type annealing furnace is improved, the heat loss and gas fuel consumption are reduced, and the operators around the bell-type annealing furnace are prevented from being scalded.

[0019] In an optional embodiment, a tower plate is provided at the outlet end of the smoke exhaust pipe, and a catalyst for catalytically decomposing nitrogen oxides in the flue gas is provided on the tower plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A front view of a bell-type annealing furnace according to an embodiment of the present invention; Figure 2 A front view of another bell-type annealing furnace according to an embodiment of the present invention; Figure 3 for Figure 2 A is a partial enlarged schematic diagram; Figure 4 for Figure 2 A partial enlarged schematic diagram of B in the middle; Figure 5 for Figure 2 A partial enlarged schematic diagram of C in the middle; Figure 6 for Figure 2 A side view of a bell annealing furnace is shown; Figure 7 for Figure 2 A top view of a bell annealing furnace is shown.

[0022] Description of reference numerals: 1. Outer cover; 2. Smoke exhaust pipe; 3. Pressure regulating pipe; 4. Heat exchanger; 5. Combustion air inlet pipe; 6. Burner; 7. Cold air pipe; 8. Hot air pipe; 9. Casing; 10. Opening regulating valve; 11. First flow regulating valve; 12. Second flow regulating valve; 13. Third flow regulating valve; 14. Proportional valve; 15. Manual butterfly valve; 16. Pressure regulating valve; 17. Pressure gauge; 18. Gas main; 19. Gas inlet pipe; 20. Air inlet pipe; 21. First fan; 22. Manual linear regulating valve; 23. Pressurized pipe; 24. One-way valve; 25. Booster pump; 26. Tower tray; 27. Exhaust pipe; 28. Compressed air pipe; 29. ​​Fourth flow regulating valve. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0024] Combine the following Figures 1 to 7 , describing an embodiment of the present invention.

[0025] According to an embodiment of the present invention, a bell-type annealing furnace is provided, comprising: Base; An inner cover is arranged on the base, and the interior of the inner cover is used for placing the steel coil; The outer cover 1 is sleeved on the outside of the inner cover and forms a combustion chamber between the outer cover 1 and the inner cover. The outer cover 1 is provided with a heat exchanger 4, and the inner chamber of the heat exchanger 4 is connected with the combustion chamber. The smoke exhaust pipe 2 is connected to the inner cavity of the heat exchanger 4, and an opening regulating valve 10 is provided on the smoke exhaust pipe 2 to maintain the gas pressure in the combustion chamber at a slightly positive pressure; The combustion air inlet pipe 5 has one end connected to the air outlet of the first fan 21, and the other end passes through the heat exchanger 4 and is connected to the burner 6 through the voltage regulator tube 3; The pressurizing pipe 23 has one end connected to the area where the combustion air inlet pipe 5 passes through the heat exchanger 4, and the other end connected to the pressure stabilizing pipe 3. A booster pump 25 is provided on the pressurizing pipe 23, and a one-way valve 24 is provided on the combustion air inlet pipe 5 corresponding to the pressurizing pipe 23; The compressed air pipe 28 is connected to the pressure-stabilizing tube 3 so as to be suitable for introducing compressed air at room temperature into the pressure-stabilizing tube 3, satisfying P4=P3+(T1-T0) / k, wherein 0.1℃ / pa≤k≤0.2℃ / pa, T1-T0≥0, P3 is the air pressure before the combustion air is pressurized, and its unit is pa; P4 is the air pressure in the pressure-stabilizing tube 3, and its unit is pa; T0 is the preset temperature after the combustion air is preheated, and its unit is ℃; T1 is the actual temperature of the combustion air after being preheated by the heat exchanger 4, and its unit is ℃.

[0026] The hood-type annealing furnace provided in this embodiment is provided with an opening regulating valve 10 to adjust the speed at which high-temperature flue gas is discharged through the exhaust pipe 2, so that the air pressure in the combustion chamber is maintained at a slightly positive pressure to avoid the air pressure in the combustion chamber being too low or too high; and a pressurizing pipe 23 and a compressed air pipe 28 are provided to increase the air pressure of the combustion-supporting air in the pressure-stabilizing tube 3, thereby increasing the oxygen content per unit volume, which is beneficial to ensuring the combustion effect of the gas fuel.

[0027] Specifically, the inner cover is buckled on the base, and the steel coil is placed inside the inner cover. The high-temperature flue gas in the combustion chamber passes through the heat exchanger 4 and enters the exhaust pipe 2, and is discharged through the exhaust pipe 2. By setting the opening regulating valve 10, when the air pressure in the combustion chamber exceeds the preset range, the opening of the opening regulating valve 10 is increased to increase the speed of the high-temperature flue gas being discharged through the exhaust pipe 2, thereby reducing the air pressure in the combustion chamber; when the air pressure in the combustion chamber is lower than the preset range, the opening of the opening regulating valve 10 is reduced to reduce the speed of the high-temperature flue gas being discharged through the exhaust pipe 2, thereby increasing the air pressure in the combustion chamber, thereby avoiding the air pressure in the combustion chamber from being too high or too low, which is conducive to ensuring the full combustion of the gas fuel, and maintaining a slight positive pressure in the combustion chamber is also conducive to the stable combustion of the gas fuel in the combustion chamber, so that the flame is more evenly distributed in the combustion chamber. Furthermore, as a feasible implementation form, when the gas pressure in the combustion chamber tends to increase or decrease, the opening size of the opening regulating valve 10 is adjusted in time to keep the gas pressure in the combustion chamber basically constant, which is beneficial to ensure the combustion stability of the gas fuel, maintain a smooth airflow state, reduce the noise generated during the combustion process, protect the hearing health of the operator, and can reduce the fatigue damage of the hood-type annealing furnace in an unstable air pressure environment, which is beneficial to extend the service life of the equipment.

[0028] The outer cover 1 is provided with a first fan 21, one end of the combustion air inlet pipe 5 is connected to the air outlet of the first fan 21, and the other end passes through the heat exchanger 4 and is connected to the pressure-stabilizing tube 3, so as to provide combustion air. The combustion air is extracted from the surrounding environment of the bell-type annealing furnace by the first fan 21, and is preheated through the heat exchanger 4. The preheated combustion air is sent to the burner 6 through the pressure-stabilizing tube 3.

[0029] Since the gas density will decrease after the temperature of the gas increases, in order to avoid too little oxygen content per unit volume of the combustion air, which will affect the combustion of the gas fuel, a maximum temperature of the preheated combustion air is preset according to actual production needs. When the temperature of the combustion air preheated by the heat exchanger 4 is higher than the preset maximum temperature, the booster pump 25 is started, and the compressed air pipe 28 simultaneously introduces compressed air at room temperature into the pressure-stabilizing tube 3; when the temperature of the preheated combustion air is lower than the preset maximum temperature, the booster pump 25 is not started. The connection between the pressurizing pipe 23 and the combustion air inlet pipe 5 is located at the inlet side of the one-way valve 24, and the connection between the pressure-stabilizing tube 3 and the combustion air inlet pipe 5 is located at the outlet side of the one-way valve 24. Since the temperature of the combustion air is further increased after being pressurized by the booster pump 25, the compressed air at normal temperature is mixed with the pressurized and heated combustion air to avoid the gas temperature in the pressure regulator tube 3 being too high, and an additional portion of oxygen is provided to enter the pressure regulator tube 3, thereby increasing the gas pressure in the pressure regulator tube 3, increasing its oxygen content per unit volume, and preventing the combustion air temperature from being too high, resulting in deflagration in the combustion chamber. Due to the presence of the one-way valve 24, the combustion air in the pressure regulator tube 3 can be prevented from flowing back to the combustion air inlet pipe 5. The gas pressure in the pressure regulator tube 3 satisfies P4=P3+(T1-T0) / k, so that the gas pressurization degree is positively correlated with the degree by which the combustion air temperature exceeds the maximum temperature, and the gas pressurization range is limited to avoid the gas pressure in the pressure regulator tube 3 being too high. Among them, an air pressure sensor is provided in the area between the heat exchanger 4 and the boost pump 25 corresponding to the combustion air inlet pipe 5, so as to detect the air pressure P3 of the combustion air before being boosted; an air pressure sensor is also provided in the pressure-stabilizing tube 3, so as to detect the air pressure P4 in the pressure-stabilizing tube.

[0030] In one embodiment, the gas pressure in the combustion chamber is defined as P1, and the gas pressure around the bell-type annealing furnace is defined as P2, wherein 50pa≤P1-P2≤80pa.

[0031] Specifically, according to practice, when the combustion chamber is maintained at a slightly positive pressure of 50Pa to 80Pa, it has better combustion and annealing effects.

[0032] Exemplarily, in some embodiments, the value of P1-P2 may be 50 Pa or 55 Pa or 60 Pa or 70 Pa or 75 Pa or 80 Pa, etc., or may be an interval range formed by any two of the above values.

[0033] In one embodiment, an air pressure sensor is provided on the outer cover 1, and the air pressure sensor is suitable for detecting the air pressure in the combustion chamber. The opening regulating valve 10 is electrically connected to the air pressure sensor so as to adjust the opening of the opening regulating valve 10 according to the air pressure in the combustion chamber detected by the air pressure sensor.

[0034] The hood-type annealing furnace provided in this embodiment is suitable for adjusting the opening of the opening regulating valve 10 according to the air pressure detected by the air pressure sensor, so as to adjust the smoke exhaust speed so that the air pressure in the combustion chamber remains basically constant or within a preset range, which is conducive to improving the degree of automation.

[0035] Specifically, the air pressure sensor is used to detect the air pressure in the combustion chamber in real time. According to actual needs, when the air pressure in the combustion chamber increases or exceeds a preset range, the opening of the opening regulating valve 10 increases. When the air pressure in the combustion chamber decreases or is lower than a preset range, the opening of the opening regulating valve 10 decreases, so that the air pressure in the combustion chamber remains basically constant or within a preset range, thereby ensuring the combustion stability of the gas fuel and the annealing effect of the metal material.

[0036] In one embodiment, a fourth flow regulating valve 29 is provided on the compressed air pipe 28; a first temperature sensor is provided in the area where the combustion air inlet pipe 5 passes through the heat exchanger 4, and the first temperature sensor is suitable for detecting the temperature of the preheated combustion air. The first temperature sensor is electrically connected to the boost pump 25 and the fourth flow regulating valve 29.

[0037] Specifically, the first temperature sensor is electrically connected to the boost pump 25 and the fourth flow regulating valve 29 through the processor, and the processor is used to receive the temperature signal detected by the first temperature sensor, and after analysis and processing, control the start or shut down of the boost pump 25 and control the on / off or opening size of the fourth flow regulating valve 29. When it is detected that the temperature of the preheated combustion air is higher than the preset maximum temperature, the boost pump 25 is controlled to start to pressurize the preheated combustion air, and the fourth flow regulating valve 29 is controlled to open to pass compressed air at room temperature into the voltage regulator tube 3, thereby increasing the oxygen content per unit volume of the voltage regulator tube 3, and reducing the temperature of the combustion air after heating and pressurization, so as to avoid excessive temperature of the gas in the voltage regulator tube 3.

[0038] In one embodiment, in combination Figure 2 and Figure 7 As shown, the bell annealing furnace also includes: The sleeve 9 is sleeved on the outside of the voltage regulator tube 3 and forms an air flow channel between the sleeve and the voltage regulator tube 3; The cold air pipe 7 is connected to the air flow channel so as to be suitable for introducing cooling gas into the air flow channel. The cold air pipe 7 is provided with a first flow regulating valve 11; One end of the hot air pipe 8 is connected to the combustion chamber, and the other end is connected to the air flow channel. The hot air pipe 8 is provided with a second flow regulating valve 12.

[0039] The hood-type annealing furnace provided in this embodiment changes the gas temperature in the air flow channel by adjusting the opening sizes of the first flow regulating valve 11 and the second flow regulating valve 12, thereby cooling or heating the combustion air in the voltage-stabilizing tube 3 to reduce the temperature fluctuation range of the combustion air entering the burner 6, which is beneficial to ensuring the combustion stability of the gas fuel.

[0040] Specifically, a second temperature sensor is provided in the voltage regulator tube 3, and the second temperature sensor is electrically connected to the first flow regulating valve 11 and the second flow regulating valve 12 through the processor. The processor is used to receive the temperature signal detected by the second temperature sensor, and after analysis and processing, control the opening size of the first flow regulating valve 11 and the second flow regulating valve 12 respectively, so as to adjust the amount of high-temperature flue gas and cooling gas entering the air flow channel, so as to adjust the gas temperature in the air flow channel, so as to cool or heat the combustion air in the voltage regulator tube 3 through the voltage regulator tube wall, and reduce the temperature fluctuation range of the combustion air entering the burner 6. The air flow channel is connected to the area between the corresponding opening regulating valve 10 and the tower plate 26 on the exhaust pipe 2 through the exhaust pipe 27, so that the gas in the air flow channel is discharged with the flue gas through the exhaust pipe 2.

[0041] The hood-type annealing furnace further includes a second fan disposed outside the outer cover 1, and the cold air duct 7 is connected to the air outlet of the second fan. When the opening of the second flow regulating valve 12 changes, the air pressure in the combustion chamber will be affected. At this time, the opening regulating valve 10 changes the exhaust speed of the exhaust pipe 2 by changing its opening size, thereby adjusting the air pressure in the combustion chamber to avoid the second flow regulating valve 12 having a greater impact on the air pressure fluctuation in the combustion chamber.

[0042] In one embodiment, in combination Figure 1 and Figure 4 as well as Figure 6 As shown, the hood-type annealing furnace also includes an air inlet pipe 20, one end of which is connected to the voltage-stabilizing tube 3, and the other end is connected to the burner 6, and a third flow regulating valve 13 is arranged on the air inlet pipe 20; the hood-type annealing furnace also includes a gas inlet pipe 19, which is connected to the burner 6 to be suitable for introducing gas fuel into the burner 6, and a proportional valve 14 is arranged on the gas inlet pipe 19 to control the amount of gas fuel entering the burner 6.

[0043] The bell-type annealing furnace provided in this embodiment controls the amount of combustion air entering the burner 6 through the third flow regulating valve 13, and controls the ratio of gas fuel and combustion air by setting a proportional valve 14 to ensure normal combustion of the gas fuel.

[0044] Specifically, a manual butterfly valve 15 is also provided on the air inlet pipe 20 to manually control the opening or closing of the air inlet pipe 20 and the flow rate of the combustion-supporting air in the air inlet pipe 20, which plays a role of insurance after the failure of the third flow regulating valve 13. A manual linear regulating valve 22 is provided on the gas inlet pipe 19 to manually control the opening and closing of the gas inlet pipe.

[0045] In one embodiment, in combination Figure 1 and Figure 6 As shown, there are multiple burners 6 , each of which is connected to at least one air inlet pipe 20 and at least one gas inlet pipe 19 , respectively. The multiple burners 6 are distributed at intervals along the circumference of the outer cover 1 .

[0046] The bell-type annealing furnace provided in this embodiment is provided with a plurality of burners 6 distributed at intervals, so as to improve the uniformity of heating the inner bell.

[0047] Specifically, the pressure-stabilizing tube 3 is connected to the burner 6 through the air inlet pipe 20, so as to provide combustion-supporting air to the burner 6; the gas main pipe 18 is connected to the burner 6 through the gas inlet pipe 19, so as to provide gas fuel to the burner 6. Preferably, in the horizontal direction, a plurality of burners 6 are evenly spaced and distributed around the outer cover 1. As a feasible implementation form, the number of the burners 6 is eight.

[0048] In one embodiment, in combination Figure 5 As shown, the bell-type annealing furnace further includes a gas main pipe 18 , a plurality of gas inlet pipes 19 are respectively connected to the gas main pipe 18 , and a pressure stabilizing valve 16 is provided on the gas main pipe 18 .

[0049] Specifically, a part of the gas main 18 is arranged around the outer cover 1. The pressure regulating valve 16 is used to adjust the gas pressure in the gas main 18 to ensure that the pressure is within a reasonable range, to ensure the safe operation of the gas system, to help the gas system to achieve more energy-saving operation, and to reduce the loss of gas. The gas main 18 is also provided with a filter and an electromagnetic shut-off valve. By setting a filter to filter various impurities in the gas pipeline, the purity and quality of the gas fuel are improved, which helps the gas fuel to burn more fully and improve the combustion efficiency. The electromagnetic shut-off valve is set to control the on and off of the gas main 18. The gas main 18 is also provided with a pressure gauge 17 and a pressure switch to detect the pressure of the gas fuel in the gas main 18. When it exceeds the set range, the supply of gas fuel is cut off to ensure the safety of the system.

[0050] In one embodiment, the outside of the sleeve 9 is wrapped with heat insulation cotton; And / or, the outside of the combustion air inlet pipe 5 is wrapped with heat insulation cotton; And / or, the outside of the air inlet pipe 20 is wrapped with heat insulation cotton; And / or, the exterior of the outer cover 1 is wrapped with heat-insulating cotton; And / or, the outside of the smoke exhaust pipe 2 is wrapped with heat insulation cotton.

[0051] The bell-type annealing furnace provided in this embodiment is provided with heat insulation cotton on the outside of the above-mentioned components to improve the heat preservation and heat insulation effect of the bell-type annealing furnace, reduce heat loss and gas fuel consumption, and avoid burns to operators around the bell-type annealing furnace.

[0052] In one embodiment, in combination Figure 1 and Figure 2 As shown, a tower tray 26 is disposed at the outlet end of the smoke exhaust pipe 2, and a catalyst for catalytically decomposing nitrogen oxides in the flue gas is disposed on the tower tray 26.

[0053] Specifically, nitrogen oxides in high-temperature flue gas undergo a decomposition reaction under the catalytic action of the catalyst to generate nitrogen and oxygen, which is beneficial to reducing environmental pollution.

[0054] Obviously, the above embodiments are only examples for clear explanation, and are not intended to limit the implementation methods. Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the present invention.

Claims

1. A bell-type annealing furnace, characterized in that: include: Base; An inner cover is arranged on the base, and the interior of the inner cover is used for placing the steel coil; An outer cover (1) is sleeved on the outside of the inner cover and forms a combustion chamber between the outer cover and the inner cover; a heat exchanger (4) is arranged on the outer cover (1), and the inner chamber of the heat exchanger (4) is in communication with the combustion chamber; A smoke exhaust pipe (2) is connected to the inner cavity of the heat exchanger (4), and an opening regulating valve (10) is provided on the smoke exhaust pipe (2) so as to maintain the gas pressure in the combustion chamber at a slightly positive pressure; A combustion air inlet pipe (5), one end of which is connected to the air outlet of the first fan (21), and the other end of which passes through the heat exchanger (4) and is connected to the burner (6) via a voltage regulator tube (3); A pressurizing pipe (23), one end of which is in communication with the region where the combustion-supporting air inlet pipe (5) passes through the heat exchanger (4), and the other end of which is in communication with the pressure-stabilizing pipe (3); a booster pump (25) is provided on the pressurizing pipe (23); and a one-way valve (24) is provided on the combustion-supporting air inlet pipe (5) corresponding to the pressurizing pipe (23); The compressed air pipe (28) is connected to the voltage regulator tube (3) so as to be suitable for introducing compressed air at room temperature into the voltage regulator tube (3), satisfying P4=P3+(T1-T0) / k, wherein 0.1°C / pa≤k≤0.2°C / pa, T1-T0≥0, P3 is the air pressure before the combustion air is pressurized, and its unit is pa; P4 is the air pressure in the voltage regulator tube (3), and its unit is pa; T0 is the preset temperature after the combustion air is preheated, and its unit is °C; T1 is the actual temperature after the combustion air is preheated, and its unit is °C.

2. The bell-type annealing furnace according to claim 1, characterized in that: The air pressure in the combustion chamber is defined as P1, and the air pressure in the surrounding environment of the bell-type annealing furnace is defined as P2, wherein 50pa≤P1-P2≤80pa.

3. The bell-type annealing furnace according to claim 2, characterized in that: The outer cover (1) is provided with an air pressure sensor, which is suitable for detecting the air pressure in the combustion chamber. The opening regulating valve (10) is electrically connected to the air pressure sensor so as to be suitable for adjusting the opening of the opening regulating valve (10) according to the air pressure in the combustion chamber detected by the air pressure sensor.

4. The bell-type annealing furnace according to claim 1, characterized in that: A fourth flow regulating valve (29) is provided on the compressed air pipe (28); a first temperature sensor is provided in the area where the combustion air inlet pipe (5) passes through the heat exchanger (4), the first temperature sensor being suitable for detecting the temperature of the preheated combustion air, and the first temperature sensor being electrically connected to the boost pump (25) and the fourth flow regulating valve (29).

5. The bell-type annealing furnace according to claim 1, characterized in that: The bell-type annealing furnace also includes: A sleeve (9) is sleeved on the outside of the voltage regulator tube (3) and forms an air flow channel between the sleeve and the voltage regulator tube (3); A cold air pipe (7) is connected to the air flow channel so as to be suitable for introducing cooling gas into the air flow channel, and a first flow regulating valve (11) is provided on the cold air pipe (7); A hot air pipe (8) has one end connected to the combustion chamber and the other end connected to the air flow channel, and a second flow regulating valve (12) is provided on the hot air pipe (8).

6. The bell-type annealing furnace according to claim 5, characterized in that: The bell-type annealing furnace further comprises an air inlet pipe (20), one end of the air inlet pipe (20) being connected to the voltage-stabilizing pipe (3) and the other end being connected to the burner (6), and a third flow regulating valve (13) being arranged on the air inlet pipe (20); the bell-type annealing furnace further comprises a gas inlet pipe (19), the gas inlet pipe (19) being connected to the burner (6) so as to be suitable for introducing gas fuel into the burner (6), and a proportional valve (14) being arranged on the gas inlet pipe (19) so as to control the amount of gas fuel entering the burner (6).

7. The bell-type annealing furnace according to claim 6, characterized in that: There are a plurality of burners (6), each of the burners (6) being respectively connected to at least one of the air inlet pipes (20) and at least one of the gas inlet pipes (19), and the plurality of burners (6) being distributed at intervals along the circumference of the outer cover (1).

8. The bell-type annealing furnace according to claim 6, characterized in that: The bell-type annealing furnace further comprises a gas main pipe (18), a plurality of gas inlet pipes (19) are respectively connected to the gas main pipe (18), and a pressure stabilizing valve (16) is provided on the gas main pipe (18).

9. The bell-type annealing furnace according to claim 6, characterized in that: The outside of the sleeve (9) is wrapped with heat-insulating cotton; and / or, the outside of the combustion air inlet pipe (5) is wrapped with heat insulation cotton; and / or, the outside of the air inlet pipe (20) is wrapped with heat-insulating cotton; And / or, the exterior of the outer cover (1) is wrapped with heat-insulating cotton; And / or, the exterior of the smoke exhaust pipe (2) is wrapped with heat insulation cotton.

10. The bell-type annealing furnace according to claim 1, characterized in that: A tower plate (26) is provided at the outlet end of the smoke exhaust pipe (2), and a catalyst for catalyzing the decomposition of nitrogen oxides in the flue gas is provided on the tower plate (26).

Images