Air door device of combustion boiler and mounting structure of air door device

Abstract

The utility model discloses an air door device of a combustion boiler and an installation structure of the air door device. The air door device comprises a rotating shaft, a transmission connecting rod mechanism connected to the rotating shaft, an adjusting blade fixed to the rotating shaft and a limiting support used for guiding the transmission connecting rod mechanism and limiting the vertical rotating position of the transmission connecting rod mechanism. The width direction of the adjusting blade is parallel to the rotating shaft, the transmission connecting rod mechanism is perpendicular to the rotating shaft, and the transmission connecting rod mechanism and the adjusting blade are arranged at an obtuse angle; the transmission connecting rod mechanism can rotate around the axial direction of the rotating shaft, the rotating shaft can be driven to rotate around the axial direction through the transmission connecting rod mechanism, and the adjusting blades can be driven to rotate synchronously when the rotating shaft rotates around the axial direction; the limiting support is provided with a plurality of limiting grooves used for limiting the rotating position of the transmission connecting rod mechanism, one end of the transmission connecting rod mechanism is connected to the rotating shaft, and the other end of the transmission connecting rod mechanism penetrates through the limiting support. The adjusting blade and the transmission connecting rod form an obtuse angle and are matched with the limiting groove of the limiting support, so that the sectional area of the air outlet can be dynamically adjusted when the blade rotates.

Description

Technical Field

[0001] This utility model relates to the field of combustion control technology for combustion boilers, particularly to alkali recovery boilers (alkali furnaces) in the pulp and paper industry, specifically to a damper device for a combustion boiler and its installation structure. Background Technology

[0002] With increasingly stringent environmental standards (such as GB 3544-2020 "Water Pollutant Discharge Standard for Pulp and Paper Industry"), alkali furnaces, as the core source of NOx (nitrogen oxides) emissions in the pulp and paper industry (accounting for 60%-80% of total plant emissions), have become a key focus for flue gas denitrification. Traditional end-of-pipe denitrification technologies such as SCR and SNCR are prone to problems such as catalyst poisoning and pipeline blockage in the complex flue gas of alkali furnaces (high alkali, high humidity), resulting in denitrification efficiency of less than 60%. Therefore, optimizing air distribution through dampers to reduce NOx generation at the source (low-NOx combustion technology) has become the mainstream development direction in the industry.

[0003] As a core component of the air supply system, the performance of the alkali furnace damper directly affects combustion efficiency and pollutant emissions. Existing dampers generally employ a mechanical adjustment structure of "manual handle + bolt and nut," controlling airflow distribution through damper opening. However, this structure is unsuitable for high-temperature alkali furnaces (furnace temperature 1000-1200℃, damper surface temperature can reach 200-300℃) and high-vibration conditions (vibration acceleration ≥5m / s² during operation). 2 Significant defects were exposed under highly alkaline conditions (black liquor volatilization and alkaline mist):

[0004] 1. High operational risk: Risk of burns from high temperatures. Traditional damper handles are only 30-50cm from the furnace (as measured in a 1500t / d alkali furnace). The radiant heat from the furnace body causes the temperature in the handle area to reach 80-120℃ (ambient temperature >50℃). Statistics from a paper mill show that in 2022, hand burns caused by damper adjustment accounted for 32% of all safety accidents in the plant. Even with high-temperature gloves, a single adjustment still requires exposure to a contact temperature >60℃ (exceeding the human safety threshold of 43℃; operation time exceeding 15 seconds poses a risk of burns).

[0005] 2. Adjustment failure risk: Risk of bolt and nut jamming; the difference in linear expansion coefficient between stainless steel bolts (e.g., 304 stainless steel) and carbon steel nuts at high temperatures (17.2 × 10⁻⁶). -6 / ℃ vs 11.1×10 -6The temperature (°C) caused the clearance between the two components to decrease by more than 50%, and after 1000 hours of operation, the thread wear reached 0.15-0.3 mm (microscopic observation data). A paper mill's monitoring revealed that the damper bolts jammed on average every 200 adjustments. When jammed, the adjustment torque increased from the initial 8 N·m to over 30 N·m (exceeding the limits of manual operation), resulting in a 20% deviation in damper opening (e.g., the designed opening was 50%, but the actual opening was only 35%), directly affecting the air distribution ratio, and causing NOx emission fluctuations of ±200 mg / m³. 3 .

[0006] 3. Inefficient airflow mixing: a bottleneck in wind speed regulation. The existing damper opening adjustment accuracy is only ±10% (mechanical limit error), and the wind speed deviation of a single damper coverage section is >25% (measured by a hot-wire anemometer). Data from a certain alkali furnace before its renovation showed that when the damper opening was <40%, the Reynolds number of the airflow inside the furnace was <10. 4 (In laminar flow state) the mixing time between black liquor droplets and air is extended by 30%, the combustion efficiency decreases by 5%-8%, and unburned organic matter causes the ash accumulation rate of the alkali furnace to increase by two times, while the NOx generation increases by 15%.

[0007] According to data from the China Paper Industry Association in 2024, the demand for denitrification retrofitting of alkali furnaces in China exceeded 2,000 units, of which 60% still used traditional dampers. The aforementioned problems lead to: ① frequent safety accidents, increasing the average annual maintenance cost per plant by 800,000 to 1.2 million yuan; ② uncontrolled air distribution causing NOx exceedances (e.g., in one plant, NOx levels suddenly rose to 800 mg / m³ due to a stuck damper). 3 (1.6 times higher than emission standards); ③ Low combustion efficiency, increasing steam energy consumption per ton of slurry by 10%-15%. Therefore, there is an urgent need for a high-temperature resistant, anti-jamming, and airflow-controllable damper device to meet the safe, efficient, and low-emission operation requirements of alkali furnaces. Utility Model Content

[0008] The purpose of this utility model is to overcome the shortcomings of the above-mentioned background technology and provide a damper device and its installation structure that meet the requirements of safe, efficient and low-emission operation of combustion furnaces.

[0009] To achieve this objective, the present invention designs a damper device for a combustion boiler, comprising a rotating shaft, a transmission linkage mechanism connected to the rotating shaft, an adjusting blade fixed to the rotating shaft, and a limiting bracket for guiding the transmission linkage mechanism and limiting its vertical rotation position. The width direction of the adjusting blade is arranged parallel to the rotating shaft, the transmission linkage mechanism is arranged perpendicular to the rotating shaft, and the transmission linkage mechanism is arranged at an obtuse angle to the adjusting blade. The transmission linkage mechanism can rotate around the axial direction of the rotating shaft, and can drive the rotating shaft to rotate around its axial direction. When the rotating shaft rotates around its axial direction, it can drive the adjusting blade to rotate synchronously. The limiting bracket has multiple limiting grooves for limiting the rotation position of the transmission linkage mechanism. One end of the transmission linkage mechanism is connected to the rotating shaft, and the other end passes through the limiting bracket.

[0010] Furthermore, the transmission linkage mechanism includes a transmission link, one end of which is connected to the rotating shaft, and the other end of which passes through the limiting bracket and is fixedly connected to a handle.

[0011] Furthermore, the transmission link is connected to the rotating shaft by an elastic buckle mechanism that can pull the transmission link in an axial direction parallel to the rotating shaft, press it into any one of the limiting grooves of the limiting bracket, and restrict the rotation position of the transmission link through the limiting groove.

[0012] Furthermore, the elastic buckling mechanism includes an elastic buckling mechanism mounting bracket fixed to the rotating shaft; a buckling guide structure fixed to the elastic buckling mechanism mounting bracket for guiding the transmission link to move axially along the rotating shaft; and an elastic connection structure for tightening the transmission link to press it into the limiting groove.

[0013] Furthermore, the snap-fit ​​guide structure includes a guide rod or guide bolt arranged parallel to the rotating shaft, one end of which is fixed to the mounting bracket of the elastic snap-fit ​​mechanism, and the other end of the guide rod or the other end of the guide bolt passes perpendicularly through the transmission link.

[0014] Furthermore, the elastic connection structure includes an elastic element coaxially sleeved on the guide rod or the guide bolt, with its two ends respectively connected to the transmission connecting rod and the elastic buckle mechanism mounting bracket.

[0015] Furthermore, a sliding guide limiting mechanism is connected between one end of the transmission link and the rotating shaft. One end of the transmission link can slide along the axial direction of the rotating shaft through the sliding guide limiting mechanism, and the sliding guide limiting mechanism can prevent relative rotation between the transmission link and the rotating shaft.

[0016] Furthermore, the sliding guide limiting mechanism includes a groove formed on the surface of the rotating shaft along the axial direction of the rotating shaft and a slider fixed to one end of the transmission connecting rod and cooperating with the groove.

[0017] Furthermore, the installation structure of the damper device of the combustion boiler described above includes a damper housing with an air inlet and an air outlet. The damper device of the combustion boiler is installed at the air outlet. The two ends of the rotating shaft are rotatably connected to the left and right side walls of the damper housing. The limiting bracket is fixed to one side surface of the damper housing. The rotating shaft can be driven by the transmission linkage mechanism to drive the adjusting blade to completely block, partially block, or completely open the air outlet.

[0018] Furthermore, the damper housing is provided with an observation hole and a coke pushing hole at the other end near the transmission linkage mechanism. A flange coaxially arranged with the inlet of the coke pushing hole is fixed thereon, and a sealing cover is hinged to the outlet of the coke pushing hole.

[0019] The beneficial effects of this utility model are as follows: In this utility model, the adjusting blades and the transmission connecting rod are arranged at an obtuse angle, and with the limiting groove of the limiting bracket, the cross-sectional area of ​​the air outlet can be dynamically adjusted when the blades rotate, realizing the stratified spraying of airflow at different heights. The transmission connecting rod is positioned by a press-and-slide mechanism (spring + guide rod), replacing the traditional bolt fixing. Operators can complete the opening adjustment with one hand in a short time, avoiding the risks of frequent disassembly and assembly in high-temperature environments. The transmission connecting rod and the rotating shaft are connected by a sliding block, allowing axial sliding of the transmission connecting rod while preventing circumferential rotation, ensuring adjustment accuracy. An observation hole and a coke pushing hole are added to the damper housing, allowing for coke removal without disassembly, significantly improving maintenance efficiency. The flange design at the inlet of the coke pushing hole protects workers during manual coke pushing operations, preventing hand injuries from contact with the edge of the hole wall. Simultaneously, a sealing cover is installed inside the damper at the outlet of the coke pushing hole to seal the combustion exhaust gas and prevent its escape. The transmission linkage mechanism is separated from the damper body. Through the elastic buckle mechanism, the temperature at the handle of the linkage is significantly reduced, which facilitates manual operation and extends the service life of the transmission components. Attached Figure Description

[0020] Figure 1 This is a front view of the installation structure of the damper device for the combustion boiler in this utility model;

[0021] Figure 2 This is a top view of the installation structure of the damper device for the combustion boiler in this utility model;

[0022] Figure 3 This is a left view of the limiting bracket in this utility model;

[0023] Figure 4 This is the front view of the composite structure of the present invention;

[0024] Figure 5 This is a right view of the composite structure of the present invention.

[0025] Among them, 1—rotating shaft, 2—transmission linkage mechanism (2.1—transmission linkage, 2.2—handle), 3—adjusting blade, 4—limiting bracket, 5—limiting groove, 6—elastic buckle mechanism mounting bracket, 7—guide bolt, 8—slide groove, 9—slider, 10—damper housing, 11—air inlet, 12—air outlet, 13—observation hole, 14—coke push hole, 15—spring, 16—observation and exhaust composite mechanism, 17—panel, 18—flip cover, 19—bearing seat, 20—handle rod, 21—connecting rod, 22—neck structure, 23—flange, 24—sealing cover. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0027] In some embodiments, the damper device of the combustion boiler is mounted on the damper housing 10 in the following structure: Figure 1As shown in Figure 4, the damper housing 10 has an air inlet 11 and an air outlet 12. The damper device of the combustion boiler is installed at the air outlet 12. The damper device includes a rotating shaft 1, a transmission linkage mechanism 2 connected to the rotating shaft 1, an adjusting blade 3 fixed to the rotating shaft 1, and a limiting bracket 4 for guiding the transmission linkage mechanism 2 and limiting its vertical rotation position. The width direction of the adjusting blade 3 is parallel to the rotating shaft 1, the transmission linkage mechanism 2 is perpendicular to the rotating shaft 1, and the transmission linkage mechanism 2 and the adjusting blade 3 are arranged at an obtuse angle. The transmission linkage mechanism 2 can rotate around the axial direction of the rotating shaft 1, and can drive the rotating shaft 1 to rotate around its axial direction. When the rotating shaft 1 rotates around its axial direction, it can drive the adjusting blade 3 to rotate synchronously. The limiting bracket 4 has multiple limiting grooves 5 corresponding to the rotation trajectory of the transmission linkage mechanism 2. One end of the transmission linkage mechanism 2 is connected to the rotating shaft 1, and the other end passes through the limiting bracket 4. The two ends of the rotating shaft 1 are rotatably connected to the left and right side walls of the damper housing 10 via bearing seats 19. The limiting bracket 4 is fixed to one side surface of the damper housing 10. The rotating shaft 1 can be driven by the transmission linkage mechanism 2 to drive the adjusting blade 3 to completely or partially block or completely open the air outlet 12. The damper housing 10 is provided with a viewing and discharging composite mechanism 16 at the other end near the transmission linkage mechanism 2. It includes a panel 17 fixed on the damper housing 10, an observation hole 13 and a coke pushing hole 14 opened on the panel 17 and the damper housing 10. The angle between the observation hole 13 and the panel 17 is 0° to 20°. A flange 23 is fixed at the inlet of the coke pushing hole 14 and arranged coaxially with it. A sealing cover 24 is hinged to the outlet of the coke pushing hole 14.

[0028] Example 1

[0029] A specific embodiment of the transmission linkage mechanism 2: The transmission linkage mechanism 2 includes a transmission linkage 2.1, one end of which is connected to a rotating shaft 1, and the other end passes through a limiting bracket 4 and is fixedly connected to a handle 2.2. The transmission linkage 2.1 includes a Z-shaped connecting rod 21 and a straight rod-shaped handle 20. An elastic snap-fit ​​mechanism is connected between the connecting rod 21 and the rotating shaft 1, which can tighten the connecting rod 21 in an axial direction parallel to the rotating shaft 1, press the handle 20 into a limiting groove 5, and position the handle 20 within any one of the limiting grooves 5 of the limiting bracket 4. A sliding guide limiting mechanism is connected between one end of the connecting rod 21 and the rotating shaft 1. One end of the connecting rod 21 can slide along the axial direction of the rotating shaft 1 through the sliding guide limiting mechanism, and the sliding guide limiting mechanism can prevent relative rotation between the transmission linkage 2.1 and the rotating shaft 1.

[0030] Example 2

[0031] A specific embodiment of the elastic locking mechanism: The elastic locking mechanism includes an elastic locking mechanism mounting bracket 6 fixed on the rotating shaft 1; a guide bolt 7 fixed on the elastic locking mechanism mounting bracket 6 for guiding the transmission connecting rod 2.1 to move axially parallel to the rotating shaft 1; and a spring 15 for tightening the connecting rod 21 to press it against the groove wall of the limiting groove 5, the spring 15 being coaxially sleeved on the guide bolt 7. One end of the guide bolt 7 is fixed to the elastic locking mechanism mounting bracket 6, and the other end passes vertically through the connecting rod 21.

[0032] Example 3

[0033] A specific embodiment of the sliding guide limiting mechanism: The sliding guide limiting mechanism includes a slide groove 8 formed on the surface of the rotating shaft 1 along the axial direction of the rotating shaft 1 and a slider 9 fixed to one end of the transmission connecting rod 2.1 and cooperating with the slide groove 8.

[0034] Based on the above-mentioned damper device for the combustion boiler, its working method is as follows: manually press the handle 2.2, the handle rod 20 disengages from the current limiting groove 5, rotate the transmission connecting rod 2.1 to adjust the damper opening of the air outlet 12. After the damper opening of the air outlet 12 reaches the positioning position, release the handle 2.2, and the handle rod 20 will rotate and cooperate with its corresponding limiting groove 5 through the tension of the spring 15, and remain in the position after rotation, thereby maintaining the current damper opening.

[0035] In summary, in this invention, the adjusting blade 3 and the transmission connecting rod 2.1 are arranged at an obtuse angle, and in conjunction with the limiting groove 5 of the limiting bracket 4, the cross-sectional area of ​​the air outlet 12 can be dynamically adjusted when the blade rotates, achieving stratified spraying of airflow at different heights. The transmission connecting rod 2.1 is positioned by a press-and-slide mechanism (spring 15 + guide bolt 7), replacing traditional bolt fixing. Operators can complete the opening adjustment with one hand in a short time, avoiding the risks of frequent disassembly and assembly in high-temperature environments. The transmission connecting rod 2.1 and the rotating shaft 1 are connected by a sliding block, allowing axial sliding of the transmission connecting rod 2.1 while preventing circumferential rotation, ensuring adjustment accuracy. The damper housing 10 is equipped with an observation hole 13 and a coking hole 14, allowing for the removal of coking without disassembly, significantly improving maintenance efficiency. In actual operation, workers frequently need to contact the inlet area of ​​the coke pushing hole 14 during coke pushing. However, the edge of the hole wall at the inlet of the coke pushing hole 14 without a flange 23 is relatively sharp. When workers are distracted or operate carelessly, their hands are easily rubbed and collided with the edge of the hole wall, resulting in scratches. Therefore, this utility model, through the structural design of the flange 23 at the inlet of the coke pushing hole 14, can protect the safety of workers during manual coke pushing operations and prevent workers from being scratched by contact with the edge of the hole wall at the inlet of the coke pushing hole 14. At the same time, a sealing cover 24 is provided inside the damper at the outlet of the coke pushing hole 14 to seal the combustion exhaust gas and prevent it from escaping. The transmission linkage mechanism is separated from the damper body, and the temperature at the handle 2.2 is significantly reduced through the elastic buckle mechanism, which facilitates manual operation and extends the service life of the transmission components. By adjusting the rotation of blade 3, the outlet cross-sectional area of ​​the damper housing 10 is reduced. Based on Bernoulli's principle in fluid dynamics, when air flows through the narrowed outlet and enters the nozzle, the velocity increases significantly, and the pressure decreases accordingly, resulting in a powerful acceleration effect. Within a very short time, the air reaches the effective wind speed required by the process, providing sufficient power for the subsequent combustion process. The rapidly achieved effective wind speed greatly enhances the initial kinetic energy of the airflow. The high-speed airflow carries more energy into the combustion zone, providing stronger power support for the combustion reaction, making the combustion process more intense and complete. The high-kinetic-energy airflow creates strong turbulence within the furnace, enhancing the mixing effect and achieving reasonable distribution and injection of airflow at different heights. This results in a uniform and orderly airflow distribution within the furnace, maintaining a stable temperature field and reliable combustion state, ensuring that the fuel burns fully and uniformly at all locations within the furnace, improving combustion efficiency, and creating extremely favorable conditions for the drying and combustion reactions of black liquor during alkali recovery.

[0036] It should be noted that the above description of the technical solutions is exemplary, and this specification may be embodied in different forms and should not be construed as limiting it to the technical solutions set forth herein. Rather, providing these descriptions will ensure that the disclosure of this utility model is thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Furthermore, the technical solutions of this utility model are defined only by the scope of the claims. The shapes, dimensions, ratios, angles, and figures disclosed in the description of various aspects of this specification and claims are merely examples, and therefore, this specification and claims are not limited to the details shown. In the following description, detailed descriptions of relevant known functions or configurations will be omitted where it is determined that they would unnecessarily obscure the focus of this specification and claims. When using the terms "comprising," "having," and "including" as described in this specification, there may also be another part or other parts, and the terms used are generally singular but may also represent plural forms.

[0037] Finally, it should be noted that the above embodiments are merely representative examples of this utility model. Obviously, this utility model is not limited to the above embodiments and can have many variations. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this utility model should be considered to fall within the protection scope of this utility model.

Claims

1. A damper device for a combustion boiler, characterized in that: It includes a rotating shaft (1), a transmission linkage mechanism (2) connected to the rotating shaft (1), an adjusting blade (3) fixed to the rotating shaft (1), and a limiting bracket (4) for guiding the transmission linkage mechanism (2) and limiting its vertical rotation position; the width direction of the adjusting blade (3) is arranged parallel to the rotating shaft (1), the transmission linkage mechanism (2) is arranged perpendicular to the rotating shaft (1), and the transmission linkage mechanism (2) is arranged at an obtuse angle to the adjusting blade (3); the transmission linkage mechanism (2) can rotate around the axial direction of the rotating shaft (1), and the rotating shaft (1) can be driven to rotate around its axial direction through the transmission linkage mechanism (2), and the adjusting blade (3) can be driven to rotate synchronously when the rotating shaft (1) rotates around its axial direction; the limiting bracket (4) is provided with multiple limiting grooves (5) for limiting the rotation position of the transmission linkage mechanism (2), one end of the transmission linkage mechanism (2) is connected to the rotating shaft (1), and the other end passes through the limiting bracket (4).

2. The damper device for a combustion boiler as described in claim 1, characterized in that: The transmission linkage mechanism (2) includes a transmission link (2.1), one end of which is connected to the rotating shaft (1), and the other end is fixedly connected to a handle (2.2) through the limiting bracket (4).

3. The damper device for a combustion boiler as described in claim 2, characterized in that: The transmission link (2.1) is connected to the rotating shaft (1) by an elastic buckling mechanism that can pull the transmission link (2.1) along the axial direction parallel to the rotating shaft (1) and press it into any one of the limiting grooves (5) of the limiting bracket (4), thereby limiting the rotation position of the transmission link (2.1) through the limiting groove (5).

4. The damper device for a combustion boiler as described in claim 3, characterized in that: The elastic buckle mechanism includes an elastic buckle mechanism mounting bracket (6) fixed on the rotating shaft (1); a buckle guide structure fixed on the elastic buckle mechanism mounting bracket (6) for guiding the transmission link (2.1) to move along the axial direction of the rotating shaft (1); and an elastic connection structure for pulling the transmission link (2.1) to press it into the limiting groove (5).

5. The damper device for a combustion boiler as described in claim 4, characterized in that: The buckle guide structure includes a guide rod or guide bolt (7) arranged parallel to the rotating shaft (1) and fixed at one end to the elastic buckle mechanism mounting bracket (6). The other end of the guide rod or the other end of the guide bolt (7) passes vertically through the transmission link (2.1).

6. The damper device for a combustion boiler as described in claim 5, characterized in that: The elastic connection structure includes an elastic element coaxially sleeved on the guide rod or the guide bolt (7), with both ends connected to the transmission connecting rod (2.1) and the elastic buckle mechanism mounting bracket (6) respectively.

7. The damper device for a combustion boiler as described in claim 2, characterized in that: A sliding guide limiting mechanism is connected between one end of the transmission link (2.1) and the rotating shaft (1). One end of the transmission link (2.1) can slide along the axial direction of the rotating shaft (1) through the sliding guide limiting mechanism, and the sliding guide limiting mechanism can prevent relative rotation between the transmission link (2.1) and the rotating shaft (1).

8. The damper device for a combustion boiler as described in claim 7, characterized in that: The sliding guide limiting mechanism includes a groove (8) formed on the surface of the rotating shaft (1) along the axial direction of the rotating shaft (1) and a slider (9) fixed to one end of the transmission connecting rod (2.1) and cooperating with the groove (8).

9. An installation structure for a damper device of a combustion boiler according to any one of claims 1-8, comprising a damper housing (10) having an air inlet (11) and an air outlet (12) thereon, characterized in that: The damper device of the combustion boiler is installed at the air outlet (12). The two ends of the rotating shaft (1) are rotatably connected to the left and right side walls of the damper housing (10). The limiting bracket (4) is fixed on one side surface of the damper housing (10). The rotating shaft (1) can be driven by the transmission linkage mechanism (2) to drive the adjusting blade (3) to completely block or partially block or completely open the air outlet (12).

10. The installation structure of the damper device for a combustion boiler as described in claim 9, characterized in that: The damper housing (10) is provided with an observation hole (13) and a coke push hole (14) at the other end near the transmission linkage mechanism (2). A flange (23) is fixed at the inlet of the coke push hole (14) and is arranged coaxially therewith. A sealing cover (24) is hinged to the outlet of the coke push hole (14).

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