Primary fan and its use method

Abstract

The present invention relates to the field of fans, and specifically to a primary fan and a method for using the primary fan, comprising a base, a fan housing, fan blades and a driving motor, wherein a motor support is fixedly mounted on the base, the fan housing is fixedly mounted on the base, and an air inlet and an air supply port are fixedly connected to the fan housing, an air supply duct is fixedly connected to the port of the air supply port, a rotating shaft is rotatably mounted on the side wall of the fan housing through a primary sealing bearing, the fan blades are located in an inner cavity of the fan housing, and the fan blades are fixedly connected to the inner end of the rotating shaft; a primary fan composed of a base, a fan housing, fan blades and a driving motor is provided, and a preheating structure composed of a plurality of heat exchange ducts is provided in the air supply duct of the fan housing, thereby effectively preheating the gas fed into the burner, thereby effectively preventing low-temperature air from entering the burner and causing the internal temperature of the burner to decrease, thereby affecting the combustion effect.

Description

Technical Field

[0001] The present invention relates to the field of fans, in particular to a primary fan and a method for using the primary fan. Background Art

[0002] The primary fan is a device that provides primary air with a certain pressure and flow rate to dry the pulverized coal and send it to the burner. It is mainly used to provide oxygen required for the combustion of volatile matter in the pulverized coal. It consists of a motor, impeller, casing, air inlet box, collector, base, adjustment control system, etc.

[0003] The existing Chinese patent document with the publication number CN204494463U discloses an air duct for a primary fan, which comprises an air duct body, at least one row of baffles with adjustable inclination angles are vertically arranged inside the air duct body, and a plurality of evenly arranged anti-wear protrusions are arranged on the windward surface of the inner wall of the air duct body on one side of the baffle, and the cross section of the anti-wear protrusion is semicircular;

[0004] However, the air duct structure of the primary fan in the above scheme is relatively simple, and it is unable to heat the primary air sent to the burner, resulting in a lower temperature of the primary air entering the burner, thereby affecting the internal temperature of the burner, thereby affecting the combustion effect, and causing a large amount of heat inside the burner to be absorbed by the lower temperature primary air, thereby causing the problem of low heat utilization. For this reason, the present invention proposes a primary fan and a method of using the same to solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a primary fan and a method of using the same to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a primary fan, comprising:

[0007] A base, on which a motor support is fixedly mounted;

[0008] A fan outer shell, wherein the fan outer shell is fixedly mounted on the base, and an air inlet and an air outlet are fixedly connected to the fan outer shell, an air supply duct is fixedly connected to the port of the air outlet, and a rotating shaft is rotatably mounted on the side wall of the fan outer shell through a primary sealed bearing;

[0009] The fan blades are located in the inner cavity of the fan outer shell and are fixedly connected to the inner end of the rotating shaft;

[0010] A drive motor, wherein the drive motor is fixed on the motor support, and the outer end of the rotating shaft is connected to the output shaft of the drive motor through a coupling;

[0011] The air supply duct is connected to the feed port of the burner, and a preheating structure is arranged in the air supply duct.

[0012] Preferably, an air inlet cavity and an exhaust cavity are fixedly installed on the outer sides of the front and rear side walls of the air supply duct, and mounting holes are opened through the front and rear side walls of the air supply duct. The preheating structure is composed of a plurality of heat exchange ducts, and the two ends of the heat exchange ducts are respectively installed in the mounting holes on the front and rear side walls of the air supply duct. A first-level connecting port is formed on the air inlet cavity, and a second-level connecting port is formed on the exhaust cavity. The first-level connecting port is connected to the smoke outlet of the burner through a smoke duct, and the second-level connecting port is connected to the exhaust duct.

[0013] Preferably, the air inlet cavity is open, and a sealing cover is fixedly installed at the opening of the air inlet cavity, a filter ball is provided on the side of the heat exchange pipe facing the air inlet cavity, a filter hole is provided on the filter ball, and a connecting pipe is provided at the port of the filter hole, the connecting pipe is threadedly connected to the heat exchange pipe, a screw seat is integrally formed at the end of the filter ball, and an hexagonal wrench hole is provided on the end face of the filter ball.

[0014] Preferably, the heat exchange pipe is inserted into the mounting hole, and a limiting ring is integrally formed on the side wall of one end of the heat exchange pipe facing the exhaust chamber. When the connecting pipe is actually tightened, the limiting ring and the connecting pipe are both set against the side wall of the air supply pipe. A limiting protrusion is integrally formed on the inner side surface of the limiting ring, and a limiting groove is provided on the rear side surface of the air supply pipe. The limiting protrusion is arranged corresponding to the limiting groove. When the heat exchange pipe is actually installed, the limiting protrusion is embedded in the limiting groove.

[0015] Preferably, the primary connection port is located directly above the air inlet cavity, and the distribution area of ​​the filter holes on the filter ball occupies one third of the surface of the filter ball, and when the connecting pipe is actually tightened, the ports of the filter holes are all arranged downward.

[0016] Preferably, a filter tube is integrally formed at the port of each filter hole, the filter tube is arranged in a trumpet shape, and the diameter of the outer end of the filter tube is smaller than the diameter of the inner end of the filter tube.

[0017] Preferably, the fan blades are composed of a base plate, an annular seat and a blade combination, the base plate is provided with a primary docking groove, the annular seat is provided with a secondary docking groove, the two ends of the blade are respectively inserted into the primary docking groove and the secondary docking groove, the annular seat is integrally formed with a connecting ear plate, and the connecting ear plate and the base plate are positioned and connected by bolts and nuts.

[0018] Preferably, a primary annular groove and a secondary annular groove are provided on the bottom plate, the primary annular groove is connected to the primary docking groove through a primary connecting groove, the secondary annular groove is connected to the primary docking groove through a secondary connecting groove, and the primary connecting groove and the secondary connecting groove are not connected, a third-level connecting groove and a fourth-level connecting groove are provided at the bottom of the secondary docking groove, the third-level connecting groove and the fourth-level connecting groove are connected through a fifth-level connecting groove, a primary air duct and a secondary air duct are provided on the blade, the primary air duct and the secondary air duct are separated, the two ends of the primary air duct are respectively aligned with the primary connecting groove and the third-level connecting groove, the two ends of the secondary air duct are respectively aligned with the secondary connecting groove and the fourth-level connecting groove, sealing gaskets are provided at the ports of the primary air duct and the secondary air duct, and the primary annular groove and the secondary annular groove are respectively connected with the primary connecting air duct and the secondary connecting air duct.

[0019] Preferably, the rotating shaft is provided with a third-level connecting airway and a fourth-level connecting airway, the inner port of the third-level connecting airway is aligned with the port of the first-level connecting airway, the inner port of the fourth-level connecting airway is aligned with the port of the second-level connecting airway, a first-level adapter is rotatably mounted on the rotating shaft through a second-level sealing bearing and a third-level sealing bearing, and a second-level adapter is rotatably mounted on the rotating shaft through a fourth-level sealing bearing and a fifth-level sealing bearing, the first-level adapter is fixedly connected to the base through a first-level bracket, and the second-level adapter is fixedly connected to the base through a second-level bracket The first-level adapter and the second-level adapter are respectively provided with a first-level pipeline connection port and a second-level pipeline connection port, the outer port of the third-level connecting airway is located between the second-level sealing bearing and the third-level sealing bearing, the outer port of the fourth-level connecting airway is located between the fourth-level sealing bearing and the fifth-level sealing bearing, the third-level connecting airway and the fourth-level connecting airway are both provided with sealing grooves at the edges of the inner ports, and the sealing grooves are both padded with sealing rubber gaskets, the first-level pipeline connection port is connected to the exhaust pipe, and the second-level pipeline connection port is connected to the exhaust pipe.

[0020] The method for using a primary fan is used to control the primary fan, the fan blades are driven by a driving motor, the high-temperature flue gas flowing out of the burner flue gas outlet enters the air inlet chamber through the flue gas duct, and exchanges heat with the gas in the air supply duct through the heat exchange duct, and then the flue gas enters the exhaust chamber, the preheated gas in the air supply duct is sent to the burner for combustion, and the flue gas in the exhaust chamber flows to the first-level adapter through the exhaust duct, and then flows to the first-level airway along the third-level connecting airway, the first-level connecting airway, the first-level annular groove, and the first-level connecting groove to the first-level airway, and flows to the second-level airway along the fourth-level connecting groove, the fifth-level connecting groove, and the third-level connecting groove, thereby exchanging heat with the gas inside the fan outer casing through the first-level airway and the second-level airway on the blades to improve heat utilization, and then the flue gas flows out along the second-level connecting groove, the second-level annular groove, the second-level connecting airway, and the fourth-level connecting airway.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. A primary fan composed of a base, a fan housing, fan blades and a driving motor is provided, and a preheating structure composed of a plurality of heat exchange pipes is provided in the air supply pipe of the fan housing, so that the gas fed into the burner is effectively preheated, thereby effectively preventing low-temperature air from entering the burner and causing the internal temperature of the burner to decrease, thereby affecting the combustion effect;

[0023] 2. The flue gas flowing out of the burner is used as the heat source of the heat exchange pipe, thereby effectively improving the utilization rate of heat and solving the problem of additional energy consumption required by ordinary heating devices, making the use of the device more energy-saving and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the front structure of the present invention;

[0025] Figure 2 It is a schematic diagram of the rear structure of the present invention;

[0026] Figure 3 A half-section view of the air supply duct of the present invention;

[0027] Figure 4 for Figure 3 A schematic diagram of the structure enlargement in the middle;

[0028] Figure 5 for Figure 3 A magnified schematic diagram of the structure at B in the middle;

[0029] Figure 6 for Figure 5 A magnified schematic diagram of the structure at C in the middle;

[0030] Figure 7This is a schematic diagram of the air supply duct structure of the present invention;

[0031] Figure 8 This is a schematic diagram of the heat exchange pipeline structure of the present invention;

[0032] Fig. 9 for Figure 8 The enlarged schematic diagram of the structure at E in the middle;

[0033] Fig.10 for Figure 8 A magnified schematic diagram of the structure at F in the middle;

[0034] Fig.11 This is a schematic diagram of the fan blade structure of the present invention;

[0035] Fig.12 This is a schematic diagram of the fan blade connection of the present invention;

[0036] Fig.13 for Fig.12 A magnified schematic diagram of the structure at G in the middle;

[0037] Fig.14 for Fig.12 A magnified schematic diagram of the structure at H in the middle;

[0038] Fig.15 for Fig.12 A magnified schematic diagram of the structure at J in the middle;

[0039] Fig.16 A half-section view of a fan blade of the present invention;

[0040] Fig.17 for Fig.16 A magnified schematic diagram of the structure at K in the middle;

[0041] Fig.18 for Fig.16 A magnified schematic diagram of the structure at L in the middle;

[0042] Fig.19 for Fig.16 The enlarged schematic diagram of the structure at M in the middle;

[0043] Fig. 20 for Fig.16 Enlarged schematic diagram of the structure at position N.

[0044] In the figure: base 1, fan housing 2, fan blades 3, drive motor 4, air inlet 5, air supply duct 6, shaft 7, motor support 8, air inlet cavity 9, exhaust cavity 10, primary connection port 11, secondary connection port 12, sealing cover 13, heat exchange pipe 14, filter ball 15, connecting pipe 16, filter hole 17, filter pipe 18, limiting ring 19, limiting protrusion 20, screw seat 21, hexagonal wrench hole 22, bottom plate 23, annular seat 24, blade 25, connecting ear plate 26, bolt and nut 27, primary docking groove 28, secondary docking groove 29, primary annular groove 30, secondary ring shaped groove 31, primary connecting groove 32, secondary connecting groove 33, tertiary connecting groove 34, fourth connecting groove 35, fifth connecting groove 36, primary air duct 37, secondary air duct 38, primary connecting air duct 39, secondary connecting air duct 40, tertiary connecting air duct 41, fourth connecting air duct 42, secondary sealed bearing 43, tertiary sealed bearing 44, primary adapter seat 45, fourth sealed bearing 46, fifth sealed bearing 47, secondary adapter seat 48, primary pipe connecting port 49, secondary pipe connecting port 50, coupling 51, primary bracket 52, secondary bracket 53, and sealing rubber gasket 54. DETAILED DESCRIPTION

[0045] In order to make the purpose and technical solution of the present invention clearly and completely described, and the advantages more clearly understood, the embodiments of the present invention are further described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are part of the embodiments of the present invention, rather than all of the embodiments, and are only used to explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] See also Figure 1-20 , the present invention provides the following four preferred embodiments:

[0047] Embodiment 1, a primary fan, comprises a base 1, a fan outer shell 2, fan blades 3 and a driving motor 4, a motor support 8 is fixedly mounted on the base 1, the fan outer shell 2 is fixedly mounted on the base 1, and an air inlet 5 and an air outlet are fixedly connected to the fan outer shell 2, an air supply duct 6 is fixedly connected to the port of the air outlet, a rotating shaft 7 is rotatably mounted on the side wall of the fan outer shell 2 through a primary sealed bearing, the fan blades 3 are located in the inner cavity of the fan outer shell 2, and the fan blades 3 are fixedly connected to the inner end of the rotating shaft 7, the driving motor 4 is fixed on the motor support 8, and the rotating shaft 7 is fixedly mounted on the side wall of the fan outer shell 2 through a primary sealed bearing, The outer end of the shaft 7 is connected to the output shaft of the drive motor 4 through a coupling 51, the air supply duct 6 is connected to the feed port of the burner, and a preheating structure is arranged in the air supply duct 6. A primary fan composed of a base 1, a fan outer shell 2, fan blades 3 and a drive motor 4 is arranged, and a preheating structure composed of a plurality of heat exchange pipes 14 is arranged in the air supply duct 6 of the fan outer shell 2, so that the gas fed into the burner is effectively preheated, thereby effectively preventing low-temperature air from entering the burner and causing the internal temperature of the burner to drop, thereby affecting the combustion effect.

[0048] Embodiment 2, on the basis of embodiment 1, an air inlet chamber 9 and an exhaust chamber 10 are fixedly installed on the outer sides of the front and rear side walls of the air supply duct 6, and mounting holes are penetrated through the front and rear side walls of the air supply duct 6. The preheating structure is composed of a plurality of heat exchange pipes 14, and the two ends of the heat exchange pipe 14 are respectively installed in the mounting holes on the front and rear side walls of the air supply duct 6. A first-level connecting port 11 is formed on the air inlet chamber 9, and a second-level connecting port 12 is formed on the exhaust chamber 10. The first-level connecting port 11 is connected to the flue gas outlet of the burner through a flue gas pipe, and the second-level connecting port 12 is connected to the exhaust pipe. The flue gas flowing out of the burner is used as the heat source of the heat exchange pipe 14, thereby effectively improving the utilization rate of heat, and can solve the problem of additional energy consumption required by ordinary heating devices, so that the use of the device is more energy-saving and environmentally friendly.

[0049] The air inlet chamber 9 is open, and a sealing cover 13 is fixedly installed at the opening of the air inlet chamber 9. A filter ball 15 is provided on the side of the heat exchange pipe 14 facing the air inlet chamber 9. A filter hole 17 is provided on the filter ball 15, and a connecting pipe 16 is provided at the end of the filter hole 17. The connecting pipe 16 is threadedly connected to the heat exchange pipe 14. A screw seat 21 is integrally formed at the end of the filter ball 15, and an inner hexagonal wrench hole 22 is provided on the end face of the filter ball 15. The filter hole 17 can filter the flue gas, thereby preventing smoke from adhering to the heat exchange pipe 14 and affecting the heat exchange efficiency.

[0050] The heat exchange pipe 14 is inserted into the mounting hole, and a limiting ring 19 is integrally formed on the side wall of one end of the heat exchange pipe 14 facing the exhaust chamber 10. When the connecting pipe 16 is actually tightened, the limiting ring 19 and the connecting pipe 16 are both set against the side wall of the air supply pipe 6. A limiting protrusion 20 is integrally formed on the inner side of the limiting ring 19, and a limiting groove is provided on the rear side of the air supply pipe 6. The limiting protrusion 20 is arranged corresponding to the limiting groove. When the heat exchange pipe 14 is actually installed, the limiting protrusion 20 is embedded in the limiting groove. Through the setting of the limiting ring 19, the filter ball 15 can simultaneously position and fix the heat exchange pipe 14 during installation, thereby facilitating the disassembly and assembly of the overall structure.

[0051] The first-level connecting port 11 is located directly above the air inlet chamber 9, and the distribution area of ​​the filter holes 17 on the filter ball 15 accounts for one-third of the surface of the filter ball 15. When the connecting pipe 16 is actually tightened, the ports of the filter holes 17 are all set downward. The filter holes 17 are set downward to allow smoke and dust to fall under the action of gravity, thereby avoiding blockage at the filter holes 17.

[0052] A filter tube 18 is integrally formed at the port of the filter hole 17. The filter tube 18 is arranged in a trumpet shape, and the outer end diameter of the filter tube 18 is smaller than the inner end diameter of the filter tube 18. By setting the filter tube 18, the risk of blockage of the filter hole 17 can be further reduced.

[0053] Embodiment 3, on the basis of embodiment 2, the fan blade 3 is composed of a base plate 23, an annular seat 24 and a blade 25. A primary docking groove 28 is provided on the base plate 23, and a secondary docking groove 29 is provided on the annular seat 24. The two ends of the blade 25 are respectively inserted into the primary docking groove 28 and the secondary docking groove 29. A connecting ear plate 26 is integrally formed on the annular seat 24. The connecting ear plate 26 and the base plate 23 are positioned and connected by bolts and nuts 27. The setting of the bolts and nuts 27 can facilitate the overall disassembly and assembly of the fan blade 3.

[0054] The bottom plate 23 is provided with a primary annular groove 30 and a secondary annular groove 31, the primary annular groove 30 is connected to the primary docking groove 28 via a primary connecting groove 32, the secondary annular groove 31 is connected to the primary docking groove 28 via a secondary connecting groove 33, and the primary connecting groove 32 and the secondary connecting groove 33 are not connected, the bottom of the secondary docking groove 29 is provided with a tertiary connecting groove 34 and a quaternary connecting groove 35, the tertiary connecting groove 34 and the quaternary connecting groove 35 are connected via a quinary connecting groove 36, and the blade 2 5 is provided with a primary air passage 37 and a secondary air passage 38, the primary air passage 37 and the secondary air passage 38 are separated from each other, the two ends of the primary air passage 37 are respectively aligned with the primary connecting groove 32 and the tertiary connecting groove 34, the two ends of the secondary air passage 38 are respectively aligned with the secondary connecting groove 33 and the quaternary connecting groove 35, sealing gaskets are provided at the ports of the primary air passage 37 and the secondary air passage 38, and the primary annular groove 30 and the secondary annular groove 31 are respectively connected with the primary connecting air passage 39 and the secondary connecting air passage 40.

[0055] The rotating shaft 7 is provided with a third-level connecting airway 41 and a fourth-level connecting airway 42, the inner port of the third-level connecting airway 41 is aligned with the port of the first-level connecting airway 39, the inner port of the fourth-level connecting airway 42 is aligned with the port of the second-level connecting airway 40, a first-level adapter 45 is rotatably mounted on the rotating shaft 7 through a second-level sealing bearing 43 and a third-level sealing bearing 44, and a second-level adapter 48 is rotatably mounted on the rotating shaft 7 through a fourth-level sealing bearing 46 and a fifth-level sealing bearing 47, the first-level adapter 45 is fixedly connected to the base 1 through a first-level bracket 52, the second-level adapter 48 is fixedly connected to the base 1 through a second-level bracket 53, and the first-level adapter 45 and the second-level adapter 48 are divided into A primary pipe connection port 49 and a secondary pipe connection port 50 are separately provided. The outer port of the tertiary connecting air duct 41 is located between the secondary sealing bearing 43 and the tertiary sealing bearing 44. The outer port of the quaternary connecting air duct 42 is located between the quaternary sealing bearing 46 and the quintuple sealing bearing 47. Sealing grooves are provided at the edges of the inner ports of the tertiary connecting air duct 41 and the quaternary connecting air duct 42. Sealing rubber gaskets 54 are padded in the sealing grooves. The primary pipe connection port 49 is connected to the exhaust pipe. The secondary pipe connection port 50 is connected to the exhaust pipe. The flue gas flowing in the primary air duct 37 and the secondary air duct 38 on the blade 25 is passed to further improve the preheating effect of the inflowing gas.

[0056] Embodiment 4, on the basis of embodiment 3, a method for using a primary fan, the method for using a primary fan is used to control the above-mentioned primary fan, the fan blades 3 are driven by the driving motor 4, the high-temperature flue gas flowing out of the flue gas outlet of the burner will enter the air inlet chamber 9 through the flue gas duct, and exchange heat with the gas in the air supply duct 6 through the heat exchange duct 14, and then the flue gas enters the exhaust chamber 10, the preheated gas in the air supply duct 6 is sent to the burner for combustion, and the flue gas in the exhaust chamber 10 will flow to a The flue gas flows along the third-stage connecting airway 41, the first-stage connecting airway 39, the first-stage annular groove 30, and the first-stage connecting groove 32 to the first-stage airway 37, and flows along the fourth-stage connecting groove 35, the fifth-stage connecting groove 36, and the third-stage connecting groove 34 to the second-stage airway 38, thereby exchanging heat with the gas inside the fan outer shell 2 through the first-stage airway 37 and the second-stage airway 38 on the blade 25 to improve the heat utilization rate, and then the flue gas flows out along the second-stage connecting groove 33, the second-stage annular groove 31, the second-stage connecting airway 40, and the fourth-stage connecting airway 42.

[0057] Although the above describes the illustrative specific implementation methods of the present application so that technicians in this technical field can understand the present application, the present application is not limited to the scope of the specific implementation methods. For ordinary technicians in this technical field, as long as various changes are within the spirit and scope of the present application defined and determined by the attached claims, all application creations using the concept of the present application are protected.

Claims

1. A primary fan, characterized in that: include: A base (1), wherein a motor support (8) is fixedly mounted on the base (1); A fan outer shell (2), the fan outer shell (2) being fixedly mounted on the base (1), and having an air inlet (5) and an air outlet fixedly connected to the fan outer shell (2), an air supply duct (6) fixedly connected to the port of the air outlet, and a rotating shaft (7) rotatably mounted on the side wall of the fan outer shell (2) via a primary sealed bearing; A fan blade (3), wherein the fan blade (3) is located in the inner cavity of the fan outer shell (2), and the fan blade (3) is fixedly connected to the inner end of the rotating shaft (7); A drive motor (4), wherein the drive motor (4) is fixed on a motor support (8), and the outer end of the rotating shaft (7) is connected to an output shaft of the drive motor (4) via a coupling (51); The air supply duct (6) is connected to the feed port of the burner, and a preheating structure is provided in the air supply duct (6); An air inlet cavity (9) and an exhaust cavity (10) are respectively fixedly mounted on the outer sides of the front and rear side walls of the air supply duct (6), and mounting holes are penetrated through the front and rear side walls of the air supply duct (6). The preheating structure is composed of a plurality of heat exchange ducts (14), and the two ends of the heat exchange ducts (14) are respectively mounted in the mounting holes on the front and rear side walls of the air supply duct (6). A primary connecting port (11) is formed on the air inlet cavity (9), and a secondary connecting port (12) is formed on the exhaust cavity (10). The primary connecting port (11) is connected to the smoke outlet of the burner through a smoke duct, and the secondary connecting port (12) is connected to the exhaust duct; The air inlet cavity (9) is open, and a sealing cover (13) is fixedly mounted at the opening of the air inlet cavity (9); a filter ball (15) is arranged on the side of the heat exchange pipe (14) facing the air inlet cavity (9); a filter hole (17) is provided on the filter ball (15); a connecting pipe (16) is provided at the end of the filter hole (17); the connecting pipe (16) is threadedly connected to the heat exchange pipe (14); a screw seat (21) is integrally formed at the end of the filter ball (15); and a hexagonal wrench hole (22) is provided on the end surface of the filter ball (15).

2. The primary fan according to claim 1, characterized in that: The heat exchange pipe (14) is inserted into the installation hole, and a limiting ring (19) is integrally formed on the side wall of one end of the heat exchange pipe (14) facing the exhaust chamber (10); when the connecting pipe (16) is actually tightened, the limiting ring (19) and the connecting pipe (16) are both arranged to abut against the side wall of the air supply pipe (6); a limiting protrusion (20) is integrally formed on the inner side surface of the limiting ring (19); a limiting groove is provided on the rear side surface of the air supply pipe (6); the limiting protrusion (20) is arranged corresponding to the limiting groove; when the heat exchange pipe (14) is actually installed, the limiting protrusion (20) is embedded in the limiting groove.

3. The primary fan according to claim 2, characterized in that: The primary connection port (11) is located directly above the air inlet cavity (9), and the distribution area of ​​the filter holes (17) on the filter ball (15) occupies one third of the surface of the filter ball (15), and when the connecting pipe (16) is actually tightened, the ports of the filter holes (17) are all arranged to face downwards.

4. The primary fan according to claim 3, characterized in that: A filter tube (18) is integrally formed at the port of each of the filter holes (17); the filter tube (18) is arranged in a trumpet shape, and the diameter of the outer end of the filter tube (18) is smaller than the diameter of the inner end of the filter tube (18).

5. The primary fan according to claim 4, characterized in that: The fan blade (3) is composed of a base plate (23), an annular seat (24) and a blade (25); the base plate (23) is provided with a primary docking groove (28); the annular seat (24) is provided with a secondary docking groove (29); two ends of the blade (25) are respectively inserted into the primary docking groove (28) and the secondary docking groove (29); a connecting ear plate (26) is integrally formed on the annular seat (24); the connecting ear plate (26) and the base plate (23) are positioned and connected by bolts and nuts (27).

6. The primary fan according to claim 5, characterized in that: The bottom plate (23) is provided with a primary annular groove (30) and a secondary annular groove (31); the primary annular groove (30) is connected to the primary docking groove (28) via a primary connecting groove (32); the secondary annular groove (31) is connected to the primary docking groove (28) via a secondary connecting groove (33); the primary connecting groove (32) and the secondary connecting groove (33) are not connected; a tertiary connecting groove (34) and a quaternary connecting groove (35) are provided at the bottom of the secondary docking groove (29); the tertiary connecting groove (34) and the quaternary connecting groove (35) are connected via a quinary connecting groove (36); the blade (25) is provided with a primary air duct (37) and a secondary air duct (38), the primary air duct (37) and the secondary air duct (38) are separated from each other, the two ends of the primary air duct (37) are respectively aligned with the primary connecting groove (32) and the tertiary connecting groove (34), the two ends of the secondary air duct (38) are respectively aligned with the secondary connecting groove (33) and the quaternary connecting groove (35), the ports of the primary air duct (37) and the secondary air duct (38) are both padded with sealing gaskets, and the primary annular groove (30) and the secondary annular groove (31) are respectively connected with the primary connecting air duct (39) and the secondary connecting air duct (40).

7. The primary fan according to claim 6, characterized in that: The rotating shaft (7) is provided with a third-level connecting airway (41) and a fourth-level connecting airway (42); the inner port of the third-level connecting airway (41) is aligned with the port of the first-level connecting airway (39); the inner port of the fourth-level connecting airway (42) is aligned with the port of the second-level connecting airway (40); a first-level transfer seat (45) is rotatably mounted on the rotating shaft (7) via a second-level sealing bearing (43) and a third-level sealing bearing (44); and a second-level transfer seat (48) is rotatably mounted on the rotating shaft (7) via a fourth-level sealing bearing (46) and a fifth-level sealing bearing (47); the first-level transfer seat (45) is fixedly connected to the base (1) via a first-level bracket (52); and the second-level transfer seat (48) is connected to the second-level bracket (53) via a second-level bracket (53). The base (1) is fixedly connected, the first-level adapter seat (45) and the second-level adapter seat (48) are respectively provided with a first-level pipeline connection port (49) and a second-level pipeline connection port (50), the outer port of the third-level connecting airway (41) is located between the second-level sealing bearing (43) and the third-level sealing bearing (44), the outer port of the fourth-level connecting airway (42) is located between the fourth-level sealing bearing (46) and the fifth-level sealing bearing (47), the third-level connecting airway (41) and the fourth-level connecting airway (42) are provided with sealing grooves at the edges of the inner ports, and the sealing grooves are padded with sealing rubber gaskets (54), the first-level pipeline connection port (49) is connected to the exhaust pipe, and the second-level pipeline connection port (50) is connected to the exhaust pipe.

8. The method for using a primary fan is characterized by: The method for using the primary fan is used to control the primary fan described in claim 7, wherein the fan blades (3) are driven by a drive motor (4), and the high-temperature flue gas flowing out of the flue gas outlet of the burner enters the air inlet chamber (9) through the flue gas duct, and exchanges heat with the gas in the air supply duct (6) through the heat exchange duct (14), and then the flue gas enters the exhaust chamber (10), and the preheated gas in the air supply duct (6) is sent to the burner for combustion, and the flue gas in the exhaust chamber (10) flows through the exhaust duct to the first-stage adapter (45), and then along the third-stage connection The flue gas flows through the air duct (41), the primary connecting air duct (39), the primary annular groove (30), and the primary connecting groove (32) to the primary air duct (37), and flows along the fourth connecting groove (35), the fifth connecting groove (36), and the third connecting groove (34) to the secondary air duct (38), thereby exchanging heat with the gas inside the fan outer casing (2) through the primary air duct (37) and the secondary air duct (38) on the blade (25), so as to improve the heat utilization rate. Then, the flue gas flows out along the secondary connecting groove (33), the secondary annular groove (31), the secondary connecting air duct (40), and the fourth connecting air duct (42).

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