Core air duct of burner

Abstract

Provided in the present utility model is a core air duct of a burner. The core air duct of a burner comprises a core air duct and a primary air duct communicated with the core air duct, the core air duct and the primary air duct forming a three-way valve. Further comprised is an annular blocking plate installed in a central opening in the core air duct; and the annular blocking plate is provided with a blocking door only allowing core air to unidirectionally flow through, and when no core air passes through the blocking door, the blocking door fully blocks the central opening of the annular blocking plate. The core air duct is obliquely placed. Such arrangement effectively enables core air in the core air duct to pass through the primary air duct more smoothly, so as to increase the rigidity of primary air, thereby facilitating burning; and such arrangement can also prevent the effect of primary air from being affected by a small amount of pulverized coal sliding into one side of the primary air duct, and can further reduce the possibility of core air ducts being burnt out due to positive pressure, thereby ensuring stable operation of unit equipment to a great extent.

Description

A core air duct of a burner Technical Field

[0001] The utility model relates to the technical field of burners, in particular to a core air duct of a burner. Background Art

[0002] The traditional boiler type is a TPC subcritical single-stage intermediate reheat natural circulation coal-fired boiler with a maximum evaporation capacity of 1,188t / h, a main steam pressure of 17.12Mpa, and a main steam temperature of 541°C; the reheat hot section steam pressure is 4.17Mpa and the temperature is 540°C. It is equipped with a steam turbine generator set, and the entire unit is arranged in a unitary manner.

[0003] Combustion air is divided into three streams: primary air, secondary air, and tertiary air. Primary air is provided by the boiler's primary fan and mixed with pulverized coal at the pulverizer. The pulverized coal and primary air mixture enters the boiler through the monolithic casing and then enters the furnace through the primary air duct. Before the pulverized coal enters the furnace, a collector casting installed at the furnace end of the primary air duct gathers the pulverized coal flow. Together with the secondary and tertiary air swirlers and flame stabilizer, this ensures a stable flame close to the burner throat.

[0004] Since positive pressure is inevitable in the boiler furnace during operation, it will cause the coal powder to flow back to the core air duct. When the ignition point of the coal powder is reached, the coal powder will burn, endangering the entire core air duct, thereby causing the entire row of burners to burn out. In severe cases, it will also affect other equipment and cause huge operational safety accidents. In addition, it also poses a serious threat to the safety of on-site personnel.

[0005] Utility Model Content

[0006] In view of the deficiencies in the prior art, the present invention provides a core air duct for a burner, which solves the problems raised in the above-mentioned background technology.

[0007] Specifically, the present invention adopts the following technical solutions:

[0008] A core air duct of a burner comprises a core air duct perpendicular to the ground and a primary air duct connected to the core air duct, wherein the core air duct and the primary air duct form a three-way valve, and the burner is characterized in that it also comprises an annular blocking plate with a central opening installed in the core air duct, wherein the annular blocking plate is provided with a blocking door for only one-way passage of the core air, and the blocking door is rotatably connected to the annular blocking plate by a pin-connected rotating mechanism; the pin-connected rotating mechanism is provided with a reset device that provides a pre-tightening force to overcome gravity, and the pre-tightening force is less than the core wind pressure.

[0009] As a further solution of the present invention, the pin-connected rotating mechanism includes a rotating pin arranged on the annular blocking plate, and a connecting plate that rotates by the rotating pin; the connecting plate is fixedly connected to the blocking door by setting a fastener.

[0010] As a further solution of the present invention, the reset device includes a fixed hinge fixed to the annular blocking plate, a reset spring sleeved on the rotating pin, and two ends of the reset spring are respectively fixedly connected to the fixed hinge and the connecting plate.

[0011] As a further solution of the present invention, the fastener includes a screw rod fixedly arranged in the middle of the door blocking portion, and a nut threadedly connected to the screw rod; the screw rod passes through the connecting plate, and the nut is abutted against the connecting plate.

[0012] As a further solution of the present invention, a nozzle is formed on the windward side of the annular baffle, with the inner wall of the core air duct being retracted toward the central opening of the annular baffle, and the nozzle is used to allow the core wind to pass through unobstructed.

[0013] As a further solution of the present invention, the core air duct is arranged obliquely to the primary air duct.

[0014] As a further solution of the present invention, the angle between the core air duct and the primary air duct is 70° to 80°.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. In terms of equipment operation, without affecting the normal operation of other equipment, the stability of the burner during use is significantly improved after the door is blocked, which increases the life of the burner and ensures the safety of equipment and personnel on site. Such a distribution can effectively make the core air of the core air duct pass through the primary air duct more smoothly, and can also increase the rigidity of the primary air, which is conducive to combustion. If it is set completely perpendicular to the primary air duct, a small amount of coal powder will slide into one side of the primary air duct, affecting the effect of the primary air, and can further reduce the possibility of the core air duct being burned due to positive pressure, thus ensuring the stable operation of the unit equipment to a great extent;

[0017] 2. In terms of equipment maintenance, the new type of blocking door has lower maintenance costs, is less prone to damage, and requires a longer replacement cycle. Spare parts only require replacing the door panel or blocking door, and the replacement process is simple and easy. Compared with not installing a blocking door, which can damage the core air duct, burner, and other equipment, the maintenance workload is reduced, work efficiency is improved, and equipment safety is enhanced.

[0018] 3. In terms of equipment processing costs, the processing steps of the new door blocking are relatively simple, so its processing costs are relatively low. At the same time, it plays a relatively important role in the later equipment operation and has a more obvious effect, so it has a high cost performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the overall structure of the utility model;

[0020] Figure 2 is a schematic diagram of the overall structure of the door blocking device of the present invention;

[0021] FIG3 is a schematic diagram of the side structure of the door blocking device of the present invention.

[0022] Figure numerals: 1. core air duct; 2. primary air duct; 3. annular blocking plate; 4. blocking door; 5. connecting plate; 6. rotating pin; 7. screw; 8. nut; 9. reset spring; 10. fixed hinge. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0024] Referring to Figure 1, this embodiment provides a core air duct of a burner, including a core air duct 1 vertical to the ground and a primary air duct 2 connected to the core air duct 1. The core air duct 1 and the primary air duct 2 form a three-way valve, and also include a circular ring-shaped blocking plate 3 with a central opening installed in the core air duct 1, with a diameter of 308mm, a thickness of 10mm, and a width of 39mm. The circular ring-shaped blocking plate 3 is welded to the inside of the air duct, and the circular ring-shaped blocking plate 3 is provided with a blocking door 4 for only one-way passage of core air. The blocking door 4 has a diameter of 240mm, and the blocking door 4 completely blocks the central opening of the circular ring-shaped blocking plate 3 when no core air passes through; on the basis of the original distribution of the core air duct 1, the core air duct 1 at the three-way valve is tilted (as shown in Figure 1), that is, the core air duct 1 is tilted to the primary air duct 2. Such a distribution can effectively make the core air of the core air duct 1 pass through the primary air duct more smoothly, increase the rigidity of the primary air, and be beneficial to combustion. If it is set completely perpendicular to the primary air duct 2, a small amount of coal powder will slide into one side of the primary air duct 2, affecting the effect of the primary air, and can further reduce the possibility of the core air duct 1 being burned due to positive pressure, thereby ensuring the stable operation of the unit equipment to a great extent.

[0025] However, the above-mentioned core air duct 1 is arranged vertically to the ground, and the blocking door 4 will be in an open state for a long time due to the influence of gravity. In order to make the blocking door 4 have a positive pressure on the primary air duct 2, the core wind pressure in the core air duct 1 is less than the positive pressure of the primary air duct 2, or when they offset each other, the blocking door 4 can overcome gravity and block the opening of the annular blocking plate 3. It is necessary to apply a pre-tightening force to the blocking door 4 so that the blocking door 4 can just block the opening of the annular blocking plate 3 when the primary air duct 2 has a positive pressure or no core wind passes through; when the core wind passes through, the core wind pressure causes the blocking door 4 to open. Specifically, the pre-tightening force is achieved by providing a reset device on the pin-connected rotating mechanism. When the core wind passes through, the wind pressure is greater than the pre-tightening force, thereby opening the blocking door 4. When there is no core wind passing or positive pressure is applied, the reset device resets the blocking door 4 to block the opening of the annular blocking plate 3.

[0026] 2 and 3 , the pin-connected rotating mechanism includes a rotating pin 6 provided on the annular blocking plate 3 and a connecting plate 5 that rotates on the rotating pin 6 ; the connecting plate 5 is fixedly connected to the blocking door 4 by fasteners.

[0027] The reset device includes a fixed hinge 10 fixed to the annular blocking plate 3, a reset spring 9 sleeved on the rotating pin 6, and two ends of the reset spring 9 are fixedly connected to the fixed hinge 10 and the connecting plate 5 respectively.

[0028] It can be known that the inclined setting means that the core air duct 1 is not vertically set to the primary air duct 2. The utility model is the most preferred one. The angle between the core air duct 1 and the primary air duct 2 is 70°~80°, which does not affect the passage of the core air and can better prevent the danger of backflow caused by positive pressure in the core air duct 1.

[0029] In order to allow the core wind to pass through the blocking door 4 without obstruction, refer to Figure 1 or Figure 2, wherein the windward side of the annular blocking plate 3 forms a nozzle that is indented from the inner wall of the core air duct 1 toward the middle opening of the annular blocking plate 3. The nozzle is used to allow the core wind to pass through unobstructed. Specifically, a circle of inner wall with an arc-shaped contour is provided between the annular blocking plate 3 and the inner wall of the core air duct 1, and the inner diameter of the end thereof facing the inside of the core air duct 1 is smaller than the inner diameter of the opening of the annular blocking plate 3.

[0030] Specifically, the fastener includes a 90 mm screw rod 7 fixedly set in the middle of the door blocking 4, and a nut 8 threadedly connected to the screw rod 7, the screw rod 7 passes through the connecting plate 5, and the nut 8 is abutted against the connecting plate 5.

[0031] During use, when the core air blows into the burner through this blocking door 4, it will be blown open. When the running burner blows the air and coal powder into the core air duct 1 due to positive pressure, the blocking door 4 will be closed, and the coal powder will be blocked from entering the core air duct 1 and reflux into the burner, which greatly enhances the stability of the burner during use, increases the life of the burner, and ensures the safety of equipment and personal safety on site.

[0032] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. In addition, in the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0033] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A core air duct of a burner, comprising a core air duct (1) vertical to the ground and a primary air duct (2) connected to the core air duct (1), wherein the core air duct (1) and the primary air duct (2) form a three-way valve, characterized in that: It also includes an annular blocking plate (3) installed in the middle opening of the core air duct (1), the annular blocking plate (3) is provided with a blocking door (4) that allows only one-way passage of the core air, and the blocking door (4) is rotatably connected to the annular blocking plate (3) by means of a pin-connected rotating mechanism; the pin-connected rotating mechanism is provided with a reset device that provides a pre-tightening force to overcome the gravity of the blocking door (4), and the pre-tightening force is less than the core wind pressure.

2. The core air duct of the burner according to claim 1, characterized in that: The pin-connected rotating mechanism comprises a rotating pin (6) arranged on the annular blocking plate (3), and a connecting plate (5) that rotates by means of the rotating pin (6); the connecting plate (5) is fixedly connected to the blocking door (4) by means of fasteners.

3. The core air duct of the burner according to claim 2, characterized in that: The reset device comprises a fixed hinge (10) fixed to the annular blocking plate (3), a reset spring (9) sleeved on the rotating pin (6), and two ends of the reset spring (9) are respectively fixedly connected to the fixed hinge (10) and the connecting plate (5).

4. The core air duct of the burner according to claim 2, characterized in that: The fastener comprises a screw rod (7) fixedly arranged in the middle of the door blocking (4), and a nut (8) threadedly connected to the screw rod (7); the screw rod (7) passes through the connecting plate (5), and the nut (8) is arranged in contact with the connecting plate (5).

5. The core air duct of the burner according to claim 1, characterized in that: The windward side of the annular blocking plate (3) forms a nozzle which is indented from the inner wall of the core air duct (1) toward the middle opening of the annular blocking plate (3), and the nozzle is used to allow the core wind to pass through unobstructed.

6. The core air duct of the burner according to claim 1, characterized in that: The core air duct (1) is arranged obliquely on the primary air duct (2).

7. The core air duct of the burner according to claim 6, characterized in that: The included angle between the core air duct (1) and the primary air duct (2) is 70° to 80°.

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