CN210799449U

CN210799449U - Centrifugal pipeline fan

Info

Publication number: CN210799449U
Application number: CN201921695597.0U
Authority: CN
Inventors: 任承钦
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-11
Filing date: 2019-10-11
Publication date: 2020-06-19
Anticipated expiration: 2029-10-11

Abstract

The utility model provides a centrifugal pipeline fan, centrifugal wind wheel, shell, wind-guiding circle and baffle including coaxial setting, the shell is including divergent pipeline section and straight tube section, the wind-guiding circle sets up in the path end of divergent pipeline section and matches the setting with the preceding rim plate of centrifugal wind wheel on shape and size for form even hoop clearance between wind-guiding circle and preceding rim plate, the big footpath end of divergent pipeline section is connected to the straight tube section, centrifugal wind wheel passes through motor base installing support and shell straight tube section fixed connection, the baffle is located centrifugal wind wheel's air outlet and fixed the setting on motor base installing support, centrifugal wind wheel's motor hold in inside the baffle, the surface of baffle be the cambered surface of convergence and constitute divergent type wind channel with the wind channel inner wall. The fan improves the flow guide effect and reduces air leakage loss through a unique air guide ring structure, and is matched with a bowl-shaped flow guide body and a shell with a gradually expanded pipe section, so that the fan is compact in structure, the performance of the fan is improved, and the efficiency of the fan is improved.

Description

Centrifugal pipeline fan

Technical Field

The utility model relates to an air treatment technical field especially relates to a but centrifugal pipeline fan of embeddable installation in wind channel.

Background

In the development of the technology of the gas conveying equipment in the modern ventilation system or other fields, a fan which can be directly embedded into an air duct or other gas conveying pipelines and has the characteristics of convenience in installation, large air volume, high pressure head, low noise, high energy efficiency and the like is often needed. At present, most core components of the pipeline type fan adopt axial flow fan blades, but the axial flow fan blades have the defects of low wind pressure and high noise and cannot meet the application requirements of certain specific occasions.

In order to solve the problems, a mode of replacing an axial flow wind wheel with a centrifugal wind wheel is generally adopted in the industry; however, in the existing pipeline fan using the centrifugal wind wheel as a core component, most wind wheel shafts adopt a design scheme of forming a right angle or a larger included angle with the axis of the pipeline, so that the air channel is too circuitous and tortuous, the flow cross-sectional area is changed violently, secondary vortexes are more, the local resistance is large, the fan efficiency is reduced, and meanwhile, the noise is also improved.

In addition, the utility model discloses still discover after the people investigation, pipeline fan still has great optimization space as ventilation system or other gas conveying equipment's core component in structural design, for example current pipeline fan is coarse at the structural design of its air intake and air outlet position department, the details is not tight to the accuse, leads to fan efficiency to be difficult to break through the bottleneck always.

The utility model discloses the people carries out the pertinence research through above-mentioned problem, designs a new pipeline fan technical scheme.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a pipeline fan that has high wind pressure, big amount of wind, high efficiency, low noise advantage and compact structure, be convenient for install to solve the problem that proposes in the background art.

In order to achieve the purpose, the utility model provides a centrifugal pipeline fan, which comprises a centrifugal wind wheel, a shell and a wind guide ring; the outer shell is sleeved outside the centrifugal wind wheel and comprises a gradually-expanded pipe section, the cross section area of the gradually-expanded pipe section is gradually increased along the gas flowing direction, the small-diameter end of the gradually-expanded pipe section is an air inlet end and is provided with an air inlet hole for installing an air inlet of the centrifugal wind wheel, and the air guide ring is arranged at the air inlet of the centrifugal wind wheel and is provided with an annular gap between the air inlet and the air inlet.

Preferably, the centrifugal wind wheel comprises a front wheel disc, a rear wheel disc, a centrifugal fan blade and a motor, wherein the front wheel disc, the centrifugal fan blade and the rear wheel disc are sequentially arranged along the gas flowing direction and are driven by the motor to rotate;

the wind guide ring is of an annular structure and coaxially sleeved outside the front wheel disc, the wind guide ring comprises a horn-shaped wind guide section, the arc shape of the wind guide section is matched with the arc shape of the gradually-expanded part of the front wheel disc, an annular gap is formed between the wind guide section and the front wheel disc, a first annular bent edge with a U-shaped section is arranged at the small-diameter end of the wind guide section, the first annular bent edge is bent towards the radial inner side of the wind guide section, the bent part of the first annular bent edge is located on the radial inner side of the wind inlet of the front wheel disc, the effect of improving the flow guide effect of the wind inlet and the aerodynamic characteristics of a fan can be achieved, and a protective gap for preventing the fan from colliding and scratching during operation is reserved between the.

Preferably, the outer shell further comprises a straight pipe section, the straight pipe section is connected with the large-diameter end of the divergent pipe section, the cross-sectional area of the straight pipe section is constant and is equal to the maximum cross-sectional area of the divergent pipe section, a partition plate is arranged at the small-diameter end of the divergent pipe section, the air inlet hole is formed in the center of the partition plate, and the large-diameter end of the air guide section on the air guide ring is fixedly connected to the partition plate through a first annular flat plate extending outwards in the radial direction.

Preferably, the pipeline fan and the inner wall of the air duct are installed in an embedded mode; the straight pipe section is provided with a hanging lug, a bayonet, a preformed hole and a slot which are convenient for the fan to be embedded and installed, and the shell can be fixedly connected to the inner wall of the air duct through the structure and plays roles of supporting, fitting and separating.

The utility model discloses in, the wind-guiding section of wind-guiding circle and the preceding rim plate of centrifugal wind wheel are the curved surface ring of gradual expansion type, and the gradual expansion line of wind-guiding section and the gradual expansion line of preceding rim plate are geometric similarity relation (according to the geometric similarity principle), and geometric similarity ratio error is no longer than 10% to former radius of curvature is between 75 ~ 100% of the latter corresponding point radius of curvature.

Preferably, the thickness of a gap between the wind guide section and the front wheel disc is not more than 15% of the diameter of the centrifugal wind wheel, and the error of the nonuniformity of the gap is not more than one time. The existence in this clearance can effectively prevent the two in-process of operation to bump and scotch, and the restriction to clearance thickness both can improve the flow resistance of gaseous in the clearance in fan operation process, can make the gaseous centrifugal force of high-speed rotation production together along with the wind wheel front disc in the clearance again, and two kinds of effects all can prevent or reduce the high-pressure gas of wind wheel air outlet department and flow back to wind wheel air inlet department again through this clearance, reduce the loss of leaking out (similar to the pump gas loss), further improve fan performance.

Preferably, the centrifugal wind wheel further comprises a flow guide body arranged at the air outlet of the centrifugal wind wheel, the flow guide body and the air guide ring are coaxially arranged and are located on the rear side of the rear wheel disc in the air flowing direction, the flow guide body comprises a flow guide section, the inside of the flow guide section is hollow and is used for accommodating the motor and accessories of the motor, the cross section area of the flow guide section is gradually reduced along the air flowing direction, the small diameter end of the flow guide section is closed or opened, a second annular bent edge is arranged at the large diameter end of the flow guide section, the second annular bent edge is bent towards the radial inner side of the flow guide section until the second annular bent edge is flush with the inner surface height of the rear wheel disc, the second annular bent edge is used for improving the aerodynamic characteristics of the air outlet of the fan, and a protection gap for preventing the fan from colliding and.

The utility model discloses in, the inside of baffle is arranged in completely to the motor base, and the gas that comes from centrifugal wind wheel air outlet department has both eliminated the disturbance of motor base to the low reaches air current of airing exhaust through the gradually-expanding type wind channel that comprises by the baffle surface with the wind channel inner wall, and reducible sudden expansion resistance loss improves the fan performance again, drives the gas flow of baffle inside through the back rim plate simultaneously, realizes the cooling heat dissipation to the motor.

Preferably, the small diameter end of the flow guide section is open, a second annular flat plate extending radially inwards is arranged at the small diameter end of the flow guide section, and the inner diameter of the second annular flat plate allows a base of the motor to penetrate through the second annular flat plate.

Preferably, still include motor base installing support, motor base installing support is U type structure and includes the main tributary fagging and is located the connecting plate at main tributary fagging both ends, the one end and the main tributary fagging fixed connection and the other end of connecting plate with shell fixed connection, the motor and the baffle of centrifugal wind wheel are all fixed to be set up on the main tributary fagging non-installation region trompil or fretwork on the main tributary fagging for alleviate the dead weight and expand the exhaust circulation section.

Preferably, the cross section of the divergent pipe section is circular or square.

Preferably, a radial adjusting gap is reserved between the second annular flat plate and the motor base and used for adjusting the coaxiality between the front wheel disc and the air guide ring or between the rear wheel disc and the flow guide body.

Preferably, a gasket A is arranged between the first annular flat plate and the partition plate and used for realizing sealing and adjusting the size and the coaxiality of a gap between the air guide ring and the front wheel disc.

Preferably, a gasket B is arranged between the base of the motor and the motor base mounting bracket and used for adjusting the mounting height and the shape and position of the motor.

Preferably, a gasket C is arranged between the second annular flat plate and the motor base mounting bracket, and is used for adjusting the mounting height and the shape and position of the flow guide body.

Preferably, a gap is reserved between the gasket B and the gasket C, so that accumulated water in the guide body can be automatically discharged under a wet working condition.

The utility model provides a technical scheme has following beneficial effect at least:

1. the utility model provides a pipeline fan carries out the aerodynamic performance that optimal design improved the fan through the structure to shell, wind-guiding circle and baffle, not only full play centrifugal wind wheel's high wind pressure characteristic, has still reduced simultaneously effectively because of the circuitous tortuous of air flow route and the influence that the flow cross-section area acutely changed and bring the fan performance, the utility model discloses the fan has possessed that the amount of wind is big, the wind pressure is high, efficient and advantage that the noise is low, still shows excellently in the aspect of compact structure nature, is convenient for install, and the whole occupation space of fan is little, therefore can be directly imbed in the wind channel, need not additionally increase the wind channel cross-section area, and the height of whole fan also only is centrifugal wind wheel, is suitable for the installation in narrow short and small wind channel, can satisfy the application demand of specific occasion.

2. The utility model discloses optimize the structure of wind-guiding circle in air intake department, and carry out strict the accuse to wind-guiding circle and centrifugal wind wheel front wheel disc clearance thickness within a definite time, in fan operation in-process, the emergence of collision and the scotch condition has been avoided to existing effect, can play good air intake water conservancy diversion effect again, improve fan aerodynamic characteristic, and can also prevent or reduce the high-pressure gas of wind wheel air outlet department and flow back to wind wheel air intake department again through this clearance, reduce the air leakage loss (similar to the pump gas loss), improve the fan performance.

3. The utility model discloses a set up the baffle, not only eliminated the motor base to the disturbance of low reaches air exhaust air current, still cooperate the gradual type wind channel that expands that the wind channel inner wall formed, reduce secondary swirl, reduce and expand resistance loss suddenly, further improve fan aerodynamic performance, improve fan efficiency, reduce fan noise, drive the inside gas flow of baffle through the back rim plate simultaneously, realize the cooling heat dissipation to the motor.

4. The utility model discloses still optimize to the many structural details of pipeline fan ① non-installation region trompil or fretwork on the main backup pad of motor base installing support for realize alleviateing the dead weight and enlarge the exhaust flow cross section, ② leaves the radial adjustment clearance between second annular flat plate and motor base for adjust between preceding rim plate and the wind-guiding circle or between back rim plate and the baffle, ③ is equipped with gasket A between first annular flat plate and baffle, is used for realizing sealing and adjusting the clearance size and the axiality between wind-guiding circle and the preceding rim plate, ④ is equipped with gasket B between the base of motor and the motor base installing support, is used for adjusting the mounting height and the position of motor, ⑤ is equipped with gasket C between second annular flat plate and the motor base installing support, is used for adjusting the mounting height and the position of baffle, ⑥ leave the clearance between gasket B and gasket C, in order to be convenient for the ponding in the water of automatically discharging in the baffle under wet condition, further optimize the aerodynamic performance of fan, improve the utility model discloses pipeline fan's suitability is favorable to the target effect of realizing.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, it is obvious that the drawings described below are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained without inventive efforts, wherein:

fig. 1 is a schematic structural view of a centrifugal pipeline fan in embodiment 1 of the present invention;

FIG. 2 is a schematic bottom view of the ducted fan of FIG. 1;

FIG. 3 is a schematic view showing an internal structure of the duct fan of FIG. 1;

FIG. 4 is an axial cross-sectional view of the duct fan of FIG. 1;

FIG. 5 is a schematic diagram of the centrifugal wind rotor of FIG. 1;

FIG. 6 is a schematic bottom view of the centrifugal rotor of FIG. 5;

FIG. 7 is a schematic structural view of the housing of FIG. 1;

FIG. 8 is a schematic view of the wind-guiding ring of FIG. 1;

FIG. 9 is a schematic view of the internal structure of the wind-guiding ring in FIG. 8;

fig. 10 is a schematic view of the structure of the current carrier of fig. 1;

fig. 11 is a schematic view of the internal structure of the current carrier of fig. 10;

FIG. 12 is an enlarged view of the structure of FIG. 11 at circled portion C;

FIG. 13 is a schematic structural view of the motor mount mounting bracket of FIG. 1;

FIG. 14 is a schematic structural view of the main support plate of FIG. 13;

fig. 15 is a schematic view of the internal structure of a centrifugal duct fan according to embodiment 2 of the present invention;

FIG. 16 is a schematic structural view of the housing of FIG. 15;

FIG. 17 is an enlarged view of the structure of FIG. 1 or FIG. 15 at circled portion A;

FIG. 18 is an enlarged view of the structure of FIG. 1 or FIG. 15 at circled portion B;

in the figure: 1 centrifugal wind wheel, 11 front wheel disc, 12 rear wheel disc, 13 centrifugal fan blade, 14 motor;

2, a shell, 21 a divergent pipe section, 22 a partition plate, 23 an air inlet and 24 a straight pipe section;

3, a wind guide ring, 31 a first annular bent edge, 32 a wind guide section and 33 a first annular flat plate;

4 flow guiding bodies, 41 second annular bent edges, 42 flow guiding sections and 43 second annular flat plates;

5, a motor base mounting bracket, a 51 main supporting plate, a 52 connecting plate and 53 ventilation holes;

61 shim a, 62 shim B, 63 shim C.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Example 1:

referring to fig. 1-4, a centrifugal pipeline fan comprises a centrifugal wind wheel 1, a shell 2, a wind guide ring 3, a flow guide body 4 and a motor base mounting bracket 5 which are coaxially mounted. The air guide ring 3 and the flow guide body 4 are respectively positioned at an air inlet and an air outlet of the centrifugal wind wheel 1, the shell 2 is sleeved outside the centrifugal wind wheel 1, and the centrifugal wind wheel 1 is fixedly connected to the shell 2 through the motor base mounting bracket 5.

Referring to fig. 5 and 6, the centrifugal wind wheel 1 is a backward inclined centrifugal wind wheel with air intake at one side and includes a front wheel disc 11, a rear wheel disc 12, a centrifugal fan blade 13 and a motor 14, the front wheel disc 11, the centrifugal fan blade 13 and the rear wheel disc 12 are sequentially arranged along an air flow direction, and the three rotate together under the driving of the motor 14, the motor 14 is an outer rotor motor, which can be a brushless motor, so as to facilitate the realization of frequency conversion speed regulation and air volume control.

Referring to fig. 7, the housing 2 is sleeved outside the centrifugal wind wheel 1 and includes a gradually expanding pipe section 21 and a straight pipe section 24 which are connected, the cross-sectional area of the gradually expanding pipe section 21 is gradually increased along the gas flowing direction, the small diameter end of the gradually expanding pipe section 21 is an air inlet end and is provided with a partition plate 22, an air inlet hole 23 for installing an air inlet of the centrifugal wind wheel is arranged on the partition plate 22, the large diameter end of the gradually expanding pipe section 21 is connected with the straight pipe section 24, and the cross-sectional area of the straight pipe section 24 is constant and equal to the maximum cross-sectional area of the gradually expanding pipe section 21.

In the present embodiment, the divergent section 21 and the straight section 24 have a square cross section.

In this embodiment, an embedded installation method is adopted between the pipeline fan and the inner wall of the air duct, so that the straight pipe section 24 is provided with a hanging lug, a bayonet, a reserved hole and a slot which are convenient for the embedded installation of the fan, and the shell 2 can be fixedly connected to the inner wall of the air duct and plays roles in supporting, fitting and isolating through the structure.

Referring to fig. 8, 9 and 17, the air guide ring 3 is of an annular structure and is sleeved outside the front wheel disc 11, and the air guide ring 3 includes a first annular bent edge 31, an air guide section 32 and a first annular flat plate 33.

The wind guide section 32 is of a horn-shaped structure, the arc surface shape of the wind guide section is matched with that of the gradually-expanded part of the front wheel disc 11, a circumferential gap is formed between the wind guide section 32 and the front wheel disc 11, the thickness of the gap is not more than 15% of the diameter of the centrifugal wind wheel, and the error of nonuniformity of the gap is not more than one time. Therefore, the flow resistance of the air in the gap can be improved in the running process of the fan, the air in the gap can rotate at a high speed along with the front wheel disc to generate centrifugal force, and the two functions can prevent or reduce the high-pressure air at the air outlet of the wind wheel from flowing back to the air inlet of the wind wheel through the gap, so that the air leakage loss is reduced, and the performance of the fan is improved.

The first annular flat plate 33 is arranged at the large-diameter end of the air guiding section 32 and extends outwards in the radial direction, the first annular flat plate 33 is fixedly connected to the partition plate 22 through screws so as to realize the fixed connection between the air guiding section 32 and the shell 2, and a gasket A61 is further arranged between the first annular flat plate 33 and the partition plate 22 and used for realizing sealing and adjusting the size of a gap and the coaxiality between the air guiding ring 3 and the front wheel disc 11.

The section of first annular crimp 31 is the U-shaped and sets up the path end at wind-guiding section 32, first annular crimp 31 bends and makes its bending part be located the radial inboard of preceding rim plate 11 air intake to the radial inboard of wind-guiding section, the terminal port parallel and level of the bending part of first annular crimp 31 and preceding rim plate 11 air intake leave between first annular crimp 31 and the preceding rim plate 11 and prevent that the fan from colliding with scotch's protection clearance when moving.

Referring to fig. 10, 11, 12 and 18, the baffle 4 is a bowl-shaped structure and includes a second annular flange 41, a baffle segment 42 and a second annular flat plate 43.

The inside of the guide section 42 is hollow, two ends of the guide section are open, the motor 14 and accessories thereof are contained in the inner space of the guide section 42, the cross-sectional area of the guide section 42 is gradually reduced along the gas flowing direction, and the outer surface of the guide section 42 is a convergent cambered surface and forms a gradually expanding air channel with the inner wall of the air channel.

The second annular bent edge 41 is arranged at the large-diameter end of the flow guide section 42, and the second annular bent edge 41 is bent towards the radial inner side of the flow guide section until the radial inner side of the flow guide section is flush with the height of the inner surface of the rear wheel disc 12, so that smooth air exhaust can be guaranteed, and secondary airflow vortex at the joint can be avoided or slowed down. The rear wheel disc 12 may be embedded in the second annular bead 41 of the baffle 4 with a protective gap between them to prevent the fan from colliding and scratching during operation.

The second annular flat plate 43 is disposed at the small diameter end of the flow guiding section 42 and extends radially inward, the inner diameter of the second annular flat plate 43 allows the base of the motor 14 to pass through, and actually, a certain radial adjusting gap is left between the second annular flat plate 43 and the base of the motor 14 for adjusting the coaxiality between the front wheel disc 11 and the air guiding ring 3 or between the rear wheel disc 12 and the flow guiding body 4.

Referring to fig. 13 and 14, the motor base mounting bracket 5 is of a U-shaped structure and includes a main support plate 51 and connection plates 52 located at two ends of the main support plate, one end of each connection plate 52 is fixedly connected with the main support plate 51, the other end of each connection plate 52 is fixedly connected with the straight pipe section 22 of the housing 2, the connection plates 52 are provided with preformed holes and bolts for facilitating mounting, and the preformed holes and the bolts are connected with the straight pipe sections 22 through the connection plates, the preformed holes and the bolts and fastened through screws; the motor 14 and the flow guiding body 4 of the centrifugal wind wheel 1 are both fixedly arranged on the main supporting plate 51, and the non-mounting areas on the two sides of the main supporting plate 51 are provided with the vent holes 53, so that the dead weight is reduced, and the ventilation section is enlarged.

In this embodiment, a spacer B62 is disposed between the base of the motor 14 and the motor base mounting bracket 5 for adjusting the mounting height and shape and position of the motor; and a gasket C63 is arranged between the second annular flat plate 43 and the motor base mounting bracket 5 and is used for adjusting the mounting height and the shape and position of the flow guide body. Meanwhile, a gap is reserved between the gasket B and the gasket C, so that accumulated water in the guide body can be automatically discharged under a wet working condition.

In this embodiment, the two annular flat plates are further respectively provided with a positioning structure for positioning the gasket.

In this embodiment, the housing 2, the air guide ring 3, the air guide 4, the motor base mounting bracket 5 and other components can be manufactured by stamping, sheet metal processing, injection molding, 3D printing or other methods, all the components are fastened by screws when being spliced, and sealing strips are adopted at the matching surfaces to realize sealing, so that seamless connection between the components and the embedded air duct inner wall is ensured, and air leakage is prevented.

Example 2:

referring to fig. 4 to 6 and fig. 8 to 18, a centrifugal duct fan has substantially the same structure and connection relationship between the structures as in embodiment 1 except that a casing 2 having a circular cross section is used in this embodiment.

The change of shell 2 can not cause the influence with the use in the actual installation of pipeline fan in this embodiment, on the contrary does the utility model discloses technical scheme provides more selections in the application under different environment, in addition, the utility model discloses the section of pipeline fan shell can also adopt the combination of other different shapes or different shapes, based on this, all only make the technical scheme of improvement to shell section shape all regard as with the utility model discloses technical scheme substantively equals, and here uses embodiment 2 as an example, and too much repeated description is no longer done to all the other deformation schemes.

The above description is only a preferred embodiment of the present invention, and does not limit the scope of the present invention, and it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Any improvement or equivalent replacement made by utilizing the contents of the specification and the drawings of the present invention can be directly or indirectly applied to other related technical fields within the spirit and principle of the present invention, and shall be included in the scope of the present invention.

Claims

1. A centrifugal pipeline fan is characterized by comprising a centrifugal wind wheel (1), a shell (2) and a wind guide ring (3); the centrifugal wind wheel is characterized in that the shell (2) is sleeved outside the centrifugal wind wheel (1) and comprises a gradually expanding pipe section (21), the cross section area of the gradually expanding pipe section (21) is gradually increased along the gas flowing direction, the small-diameter end of the gradually expanding pipe section (21) is an air inlet end and is provided with an air inlet hole (23) used for installing an air inlet of the centrifugal wind wheel, and the air guide ring (3) is arranged at the air inlet of the centrifugal wind wheel (1) and is provided with an annular gap between the air inlet and the air inlet.

2. The centrifugal pipeline fan according to claim 1, wherein the centrifugal wind wheel (1) comprises a front wheel disc (11), a rear wheel disc (12), a centrifugal fan blade (13) and a motor (14), the front wheel disc (11), the centrifugal fan blade (13) and the rear wheel disc (12) are sequentially arranged along a gas flow direction, and the three are driven by the motor (14) to rotate;

the wind guide ring (3) is of an annular structure and coaxially sleeved outside the front wheel disc (11), the wind guide ring (3) comprises a horn-shaped wind guide section (32), the arc shape of the wind guide section (32) is matched with the arc shape of the gradually-expanded part of the front wheel disc (11) and forms a circumferential gap between the wind guide section and the front wheel disc, a first annular bent edge (31) with a U-shaped section is arranged at the small diameter end of the wind guide section (32), the first annular bent edge (31) is bent towards the radial inner side of the wind guide section and enables the bent part to be located at the radial inner side of an air inlet of the front wheel disc (11), and a protective gap for preventing a fan from colliding and scratching during operation is reserved between the first annular bent edge (31) and the front wheel disc (11).

3. The centrifugal pipeline fan as claimed in claim 2, wherein the housing (2) further comprises a straight pipe section (24), the straight pipe section (24) is connected with the large diameter end of the divergent pipe section (21), the cross sectional area of the straight pipe section (24) is constant and equal to the maximum cross sectional area of the divergent pipe section (21), a partition plate (22) is arranged at the small diameter end of the divergent pipe section (21), the air inlet hole (23) is arranged at the central position of the partition plate (22), and the large diameter end of the air guide section (32) on the air guide ring (3) is fixedly connected to the partition plate (22) through a first annular flat plate (33) extending radially outwards.

4. The centrifugal pipeline fan according to claim 2 or 3, wherein the thickness of the gap between the wind guide section (32) and the front wheel disc (11) is not more than 15% of the diameter of the centrifugal wind wheel, and the error of the nonuniformity of the gap is not more than one time.

5. The centrifugal duct fan according to claim 3, characterized in that a gasket A (61) is arranged between the first annular flat plate (33) and the partition plate (22) for sealing and adjusting the gap size and coaxiality between the air guide ring (3) and the front wheel disc (11).

6. The centrifugal pipeline fan according to claim 2 or 3, further comprising a flow guide body (4) arranged at an air outlet of the centrifugal wind wheel (1), wherein the flow guide body (4) and the air guide ring (3) are coaxially arranged and are located on the rear side of the rear wheel disc (12) in the air flowing direction, the flow guide body (4) comprises a flow guide section (42), the flow guide section (42) is hollow and is used for accommodating the motor (14) and accessories thereof, the cross-sectional area of the flow guide section (42) is gradually reduced along the air flowing direction, the small-diameter end of the flow guide section (42) is closed or opened, a second annular bent edge (41) is arranged at the large-diameter end of the flow guide section (42), the second annular bent edge (41) is bent towards the radial inner side of the flow guide section until the second annular bent edge is flush with the height of the inner surface of the rear wheel disc (12), the rear wheel disc (12) is embedded into the second annular bent edge (41) of the flow guide body (4), and a space is reserved Collision and scratch protection gaps.

7. The centrifugal duct fan of claim 6, wherein the flow guide section (42) is open at a small diameter end thereof, and a second annular flat plate (43) extending radially inward is provided at the small diameter end of the flow guide section (42), and the second annular flat plate (43) has an inner diameter allowing a base of the motor (14) to pass therethrough.

8. The centrifugal pipeline fan according to claim 7, further comprising a motor base mounting bracket (5), wherein the motor base mounting bracket (5) is of a U-shaped structure and comprises a main support plate (51) and connecting plates (52) located at two ends of the main support plate, one end of each connecting plate (52) is fixedly connected with the main support plate (51) and the other end of each connecting plate is fixedly connected with the housing (2), the motor (14) and the flow guide body (4) of the centrifugal wind wheel (1) are fixedly arranged on the main support plate (51), and a non-mounting area on the main support plate (51) is provided with holes or hollows for reducing self weight and enlarging a ventilation section.

9. The centrifugal duct fan according to claim 8, characterized in that a radial adjustment gap is left between the second annular flat plate (43) and the base of the motor (14) for adjusting the coaxiality between the front wheel disc (11) and the air guide ring (3) or between the rear wheel disc (12) and the flow conductor (4);

a gasket B (62) is arranged between the base of the motor (14) and the motor base mounting bracket (5) and is used for adjusting the mounting height and the shape and position of the motor;

and a gasket C (63) is arranged between the second annular flat plate (43) and the motor base mounting bracket (5) and is used for adjusting the mounting height and the shape and position of the flow guide body.

10. The centrifugal pipeline fan of claim 9, wherein a gap is left between the gasket B and the gasket C to facilitate automatic drainage of accumulated water in the flow guide under wet conditions.