CN116221147A

CN116221147A - Centrifugal fan capable of preventing gas backflow

Info

Publication number: CN116221147A
Application number: CN202310507263.0A
Authority: CN
Inventors: 邱勇; 赵鹰; 吴健; 赵凌云; 陆杰; 倪安民
Original assignee: Far East Shuangcheng Fan Jiangsu Co ltd
Current assignee: Far East Shuangcheng Fan Jiangsu Co ltd
Priority date: 2023-05-08
Filing date: 2023-05-08
Publication date: 2023-06-06
Anticipated expiration: 2043-05-08
Also published as: CN116221147B

Abstract

The invention relates to the technical field of fans, in particular to a centrifugal fan capable of preventing gas from flowing back, which comprises an inlet shell, an impeller, guide vanes, a rear shell, a rotor component, a motor and a volute, wherein the inlet shell and the rear shell are respectively arranged at two sides of the volute, the rotor component is rotatably arranged on the inner wall of the rear shell, the impeller is arranged at the end part of the rotor component, the rotor component is in transmission connection with the motor arranged outside the rear shell, the guide vanes are arranged on the inner wall of the volute or the rear shell, the guide vanes are positioned at the periphery of the impeller, and the guide vanes are provided with guide structures for connecting an impeller outlet placing angle and a volute spiral angle. The guide vane comprises an inflow ring, an outflow ring and guide vanes, wherein the inflow ring and the outflow ring respectively take the central line of the rotor part as an axis, a plurality of guide vanes which are radially arranged on the central line of the rotor part are arranged between the inflow ring and the outflow ring, the outlet setting angles of the guide vanes are fixed, and the inlet setting angles of the guide vanes are adjustable.

Description

Centrifugal fan capable of preventing gas backflow

Technical Field

The invention relates to the technical field of fans, in particular to a centrifugal fan capable of preventing gas from flowing back.

Background

Industrial and civil applications require the use of fans to accomplish this when large flows of mobilized gas are desired. For example, dustproof ventilation of industrial plants, and ventilation of subways, high-rise interiors, gymnasiums and other public places are required by using large fans.

The centrifugal fan can provide larger full pressure for gas and is mostly used in occasions with longer ventilation pipelines. The centrifugal fan converts the speed potential energy of the impeller outlet into pressure potential energy to be transmitted backwards by using a volute structure, but the outflow angle of the gas at the impeller outlet is changed due to the compressibility of the gas under different gas flows, and the volute is a static structure, so that the gas impact and the mechanical energy loss can be caused by the mismatching of the outflow angles of the gas flow.

In addition, the impeller is a moving part, the fan inlet shell is a static part, a gap is needed to exist between the impeller and the static part, otherwise abrasion is caused, the two sides of the gap are respectively pressurized gas subjected to impeller pressurization and low-pressure gas subjected to impeller inlet, and partial air flowing out of the fan flows back to the fan from a gap between the impeller and the inlet shell to enter the fan to cause flow loss, so that the working efficiency of the fan is influenced, and the aspects are considered in the aspect that the current centrifugal fan is used for improving the working efficiency, and in the prior art, the factors which influence the efficiency are tolerated due to the consideration of simple structure and reduction of the failure rate exist.

Disclosure of Invention

The invention aims to provide a centrifugal fan capable of preventing gas from flowing back, so as to solve the problems in the background art.

In order to solve the technical problems, the invention provides the following technical scheme:

the utility model provides a centrifugal fan that can prevent gaseous backward flow, centrifugal fan includes import shell, impeller, stator, backshell, rotor part, motor, spiral case, import shell and backshell are installed respectively to spiral case both sides, rotor part rotates and installs on the backshell inner wall, rotor part tip sets up the impeller, rotor part is connected with the motor drive that sets up outside the backshell, the stator is installed on spiral case or backshell inner wall, the stator is located the impeller periphery, the stator has the water conservancy diversion structure that links up impeller export laying angle and spiral case helix angle.

The impeller rotates to do work, air flow is sucked from the inlet shell, the guide vane guides air with high speed and low pressure at the outlet of the impeller once, the air flow is converted into a direction which is suitable for the volute to accept and flows into the volute cavity, then outflow is collected at the outlet of the volute, the guide vane reduces the abrupt change degree of the air flow direction of the outlet of the impeller and the volute, more air flows without impact as much as possible, the inlet shell, the rear shell and the volute jointly enclose into a flow cavity with only an air flow inlet and an air flow outlet, the three are static components, and the impeller and the rotor component are moving components.

The inlet shell comprises a guide opening and a connecting plate, the impeller comprises a front cover plate, a working blade and a rear cover plate,

the connecting plate is fixedly connected with the volute, the central opening of the connecting plate is connected with the guide opening, the guide opening is of a reduced shape, one end with a small caliber is close to the impeller,

the front cover plate and the rear cover plate are connected with the working vane, the central position of the rear cover plate is fixed with the rotor component,

an annular labyrinth groove is formed in the surface of one side, facing the impeller, of the connecting plate, a labyrinth embedding ring is arranged at the end, facing the connecting plate, of the front cover plate, the labyrinth embedding ring is embedded into the labyrinth groove, and the labyrinth embedding ring and the labyrinth groove both take the central line of the rotor part as an axis.

The guide opening gathers the inlet air flow, steadily guides into the impeller axial inlet, the bell mouth can suck more air, the labyrinth groove is matched with the labyrinth embedding ring, the gap between the bell mouth and the labyrinth embedding ring is the leakage gap between the chamber in the volute connected with the impeller outlet and the impeller inlet, and the labyrinth type air flow-through device is arranged as a labyrinth type channel, so that the flow resistance of the air in the gap is increased, the backflow of the high-pressure air at the outlet to the low-pressure position of the impeller inlet is inhibited, and the flow loss is reduced.

The guide vane comprises an inflow ring, an outflow ring and guide vanes, wherein the inflow ring and the outflow ring respectively take the central line of the rotor part as an axis, a plurality of guide vanes which are radially arranged on the central line of the rotor part are arranged between the inflow ring and the outflow ring, the outlet setting angles of the guide vanes are fixed, and the inlet setting angles of the guide vanes are adjustable.

In the case that the air has compressibility, the flow and the rotating speed of the fan are not linearly related any more, but have offset, the flow rate of the outlet of the impeller is high in a high-flow state, the pressure is low, the air mass of the same substance has larger volume, namely, the absolute speed of the air and the tangential angle of the rim are larger than those obtained by similar theoretical conversion in the high-flow state, so the inlet setting angle of the guide vane is adjusted to adapt to the absolute speed direction of the air at the outlet of the impeller in the high-flow state, and if the air compressibility is not considered, the air at the outlet of the impeller collides with the guide vane or the volute at a large angle under the deviation from the design working condition, namely, the deviation from the design flow and the rotating speed, so mechanical energy is lost.

The inlet mounting angle of the guide vane interlocks with the rotational speed of the rotor component, and increases as the rotational speed of the rotor component increases.

The rotational speed of the rotor part is used as a basis for the change, since the rotational speed increase of the rotor part means an increase in the fan flow, after which the angular change in the absolute flow rate due to the compressibility of the gas is fine-tuned.

The guide vane also comprises a hub disc and a hub sleeve, the hub sleeve is rotatably mounted on the inner wall of the rear shell, the outer surface of the hub sleeve is fixed with the end face of the inflow ring through the hub disc, the axial direction of the hub sleeve is limited along the axial direction of the rotor component, and the stay angle of the hub sleeve changes along with the rotating speed of the rotor component.

The outflow ring is a fixed part, the position of the outflow ring is not changed in all running processes of the fan, the inflow ring is required to be correspondingly adjusted when the rotating speed of the fan motor is changed, and after the inflow ring and the outflow ring relatively rotate on the circumference for one angle, the inlet setting angle of the guide vane arranged between the inflow ring and the outflow ring can be correspondingly changed, so that the guide vane has larger rigidity or the position of the guide vane is kept limited at the outlet position, and the outlet setting angle is ensured to be unchanged.

The rotor component comprises a main shaft, a fixed sleeve, a centrifugal block, a sliding sleeve and an axial translation sleeve, wherein the main shaft is rotatably arranged on the inner wall of a rear shell, one end of the main shaft is connected with a motor in a transmission manner, the other end of the main shaft is connected with an impeller, the main shaft is respectively sleeved with the fixed sleeve and the sliding sleeve, the fixed sleeve is relatively fixed with the main shaft, the sliding sleeve is in circumferential transmission and axial sliding connection with the main shaft, the sliding sleeve and the fixed sleeve are both hinged with the centrifugal block through connecting rods, the outer surface of the sliding sleeve radially extends and is sleeved with the axial translation sleeve at the outer edge, the outer surface of the axial translation sleeve is in threaded connection with the inner surface of the hub sleeve, and the sliding sleeve is axially embedded with the axial translation sleeve to limit and circumferentially rotate to be in contact.

When the rotating speed of the main shaft changes, the centrifugal block has unequal centrifugal force, the sliding sleeve is pulled to axially slide along the surface of the main shaft, the sliding sleeve axially pushes the axial translation sleeve to be positioned at different axial positions, the axial translation sleeve is in threaded engagement with the hub sleeve, and the hub sleeve is pushed to rotate by an angle, so that the inflow ring can also rotate by an angle, and the corresponding linkage relation between the circumferential stay angle of the inflow ring relative to the main shaft and the rotating speed of the main shaft is realized.

The guide blade is a split sliding sheet type at one side close to the inflow ring. The sliding sheets of the guide vanes can be in sliding connection at the joint surface, the sliding sheets are sequentially stacked like a folding fan, the stacking degree is based on the rotation of the flow inlet ring, the setting angles of the receiving air flows of the flow inlet positions with different stacking degrees are gradually changed, the setting mode is in consideration of not occupying the torque of the main shaft, if the elastic guide sheets with larger rigidity are used, the flow inlet ring is expected to return by the elastic reaction force when staying at the expected angle, the flow inlet ring also has the tendency of returning to the initial state, the factors can apply a reaction torque to the main shaft at the sliding sleeve, a part of main shaft power is consumed, and the guide vanes with different folding degrees do not need maintaining force and only need to apply force when in change.

The transmission of the rotor component and the motor is belt transmission. The belt drive prevents fan overload, which must be considered especially in forward-curved blade fans.

The inlet end face of the inlet shell is provided with a filter screen. Prevent the suction of sundries in the plastic bag, impact the impeller blades and the blades in the guide vanes to influence the working efficiency.

Compared with the prior art, the invention has the following beneficial effects: according to the invention, the labyrinth structure is used for inhibiting flow loss of the impeller inlet and outlet from the gap of the front cover plate, the guide vane is connected with the impeller outlet and the volute, the setting angle of the guide vane inlet is automatically adjusted at different rotating speeds, the micro-variation of the gas outflow direction at the impeller outlet under different flow rates is matched, the smooth transition of the flow channel is maintained, and the impact of gas is prevented from influencing the working efficiency.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention. In the drawings:

FIG. 1 is a schematic view of the overall structure of the present invention;

fig. 2 is view a of fig. 1;

FIG. 3 is a schematic structural view of a vane of the present invention;

fig. 4 is view B of fig. 1;

FIG. 5 is an axial cross-sectional view of the impeller, vane, volute of the present invention;

FIG. 6 is a graph of a triangular analysis of gas velocity at the impeller outlet at different flow rates in accordance with the present invention;

fig. 7 is view C of fig. 5;

fig. 8 is view D in fig. 7;

in the figure: 1-inlet shell, 11-guiding port, 12-connecting plate, 121-labyrinth groove, 2-impeller, 21-front cover plate, 211-labyrinth embedding ring, 22-working vane, 3-guide vane, 31-inflow ring, 32-outflow ring, 33-guiding vane, 34-hub plate, 35-hub sleeve, 4-rear shell, 5-rotor component, 51-main shaft, 52-fixed sleeve, 53-centrifugal block, 54-sliding sleeve, 55-axial translation sleeve, 6-motor, 7-volute and 9-motor seat.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The utility model provides a centrifugal fan that can prevent gaseous backward flow, centrifugal fan includes import shell 1, impeller 2, stator 3, backshell 4, rotor part 5, motor 6, spiral case 7, import shell 1 and backshell 4 are installed respectively to spiral case 7 both sides, rotor part 5 rotates and installs on backshell 4 inner wall, rotor part 5 tip sets up impeller 2, rotor part 5 is connected with the motor 6 transmission that sets up outside backshell 4, stator 3 is installed on spiral case 7 or backshell 4 inner wall, stator 3 is located impeller 2 periphery, stator 3 has the water conservancy diversion structure that links up impeller 2 export laying angle and spiral case 7 helix angle.

As shown in fig. 1 and 5, the impeller 2 rotates to do work, air flow is sucked from the inlet housing 1, the guide vane 3 guides the air with high speed and low pressure at the outlet of the impeller 2 once, the air flow is converted into a direction suitable for the volute 7 to be accepted and guided into a cavity of the volute 7, then outflow is collected at the outlet of the volute 7, the guide vane 3 reduces the abrupt change degree of the air flow directions of the outlet of the impeller 2 and the volute 7, more air flows without impact as much as possible, the inlet housing 1, the rear housing 4 and the volute 7 jointly enclose a flow cavity with only an air flow inlet and an air flow outlet, the three are static components, and the impeller 2 and the rotor component 5 are moving components.

The inlet housing 1 comprises a guide opening 11, a connecting plate 12, the impeller 2 comprises a front cover plate 21, a working vane 22 and a rear cover plate,

the connecting plate 12 is fixedly connected with the volute 7, the center of the connecting plate 12 is opened and is connected with the guide opening 11, the guide opening 11 is in a reduced shape, one end with small caliber is close to the impeller 2,

the front cover plate 21 and the rear cover plate are connected with the working vanes 22, the central position of the rear cover plate is fixed with the rotor part 5,

an annular labyrinth groove 121 is formed in the surface of the connecting plate 12 facing the impeller 2, a labyrinth insert ring 211 is formed in the end of the front cover plate 21 facing the connecting plate 12, the labyrinth insert ring 211 is inserted into the labyrinth groove 121, and the labyrinth insert ring 211 and the labyrinth groove 121 both take the center line of the rotor part 5 as an axis.

As shown in fig. 1 and 2, the guiding port 11 gathers the inlet air flow, and stably guides the air flow into the axial inlet of the impeller 2, the bell mouth can suck more air, the labyrinth groove 121 is matched with the labyrinth embedding ring 211, the gap between the labyrinth groove and the labyrinth embedding ring is a leakage gap between the chamber in the volute 7 connected with the outlet of the impeller 2 and the inlet position of the impeller 2, and the labyrinth type air flow guiding device is provided with a labyrinth type channel, so that the flow resistance of the air in the gap is increased, the backflow of the high-pressure air at the outlet to the low-pressure position of the inlet of the impeller 2 is inhibited, and the flow loss is reduced.

The guide vane 3 comprises an inlet ring 31, an outlet ring 32 and guide vanes 33, wherein the inlet ring 31 and the outlet ring 32 respectively take the central line of the rotor part 5 as an axis, a plurality of guide vanes 33 which are radially arranged on the central line of the rotor part 5 are arranged between the inlet ring 31 and the outlet ring 32, the outlet setting angles of the guide vanes 33 are fixed, and the inlet setting angles of the guide vanes 33 are adjustable.

As shown in fig. 3,5 and 6, the radial two ends of the guide vane 33 are respectively mounted on the inlet ring 31 and the outlet ring 32, the mounting angle of the guide vane 33 at the outlet ring 32 is the outlet mounting angle, which needs to be matched with the spiral angle of the spiral case 7, the mounting angle of the guide vane 33 at the inlet ring 31 is the inlet mounting angle, the inlet mounting angle of the guide vane 33 needs to be matched with the space angle of the absolute velocity of the air flow from the outlet of the impeller 2, in fig. 5, cr is the radial velocity of the air flowing out from the outlet of the impeller 2, and Cw is the relative velocity of the air and the outlet of the impeller 2, because the impeller blades push the air to do work, the direction of Cw is the outlet mounting angle beta 2 of the impeller blades, the relative velocity Cw is combined with the circumferential rotation speed U of the impeller 2 to be the absolute velocity C of the air flowing out from the impeller 2, and the angle between the absolute velocity C and the tangential line of the outlet of the impeller 2 is the absolute velocity direction of the air flowing out

The product of the projection speed Cu of the absolute speed C in the circumferential direction and the circumferential line speed U is the rim work of the impeller 2, the radial speed Cr depends on the flow Q of the fan, the circumferential line speed U depends on the impeller rotating speed n, and the design theory in an impeller acting system is that under the condition of the size determination of the impeller"similarity theory", in both conditions, Q1/q2=cr1/cr2=u1/U2, so that under this basic design theory the absolute velocity outflow direction of the gas at the outlet of the impeller 2 is +.>

Are all unchanged, but in the case of considering that the gas has compressibility, the state equation of the gas needs to be comprehensively considered: />

The air is sucked in at the same pressure at the inlet of the fan, and the outlet of the impeller 2 has high flow velocity and low pressure in a large flow state, and the air mass of the same substance has larger volume, namely, the absolute velocity of the air and the tangential angle of the rim in the large flow state +.>

Will be compared to +.>

The inlet setting angle of the guide vane 33 should be adjusted to accommodate the absolute velocity direction of the gas at the outlet of the impeller 2 in a large flow condition, and if the compressibility of the gas is not considered, the gas at the outlet of the impeller 2 collides with the guide vane 3 or the volute 7 at a large angle in a deviation from the design condition, that is, from the design flow rate and the rotational speed, and mechanical energy is lost. It should be noted that the impeller 2 type aimed at when the outlet flow velocity is analyzed is a forward bending blade type, and for a backward bending fan, a speed triangle in a design theory is used for angular analysis for additional analysis, but since the backward bending blade is mostly used in a low flow occasion, the change of the outflow angle due to the gas compressibility is smaller, the effect of efficiency is smaller, and the adjustment structure of the inlet setting angle of the guide blade is not discussed and set.

The inlet setting angle of the guide vane 33 interlocks with the rotational speed of the rotor member 5, and the inlet setting angle of the guide vane 33 is increased when the rotational speed of the rotor member 5 is raised.

The rotational speed of the rotor part 5 is used as a basis for the change, since a rotational speed increase of the rotor part 5 means an increase in the fan flow, after which the angular change in the absolute flow rate due to the compressibility of the gas is fine-tuned.

The guide vane 3 further comprises a hub disc 34 and a hub sleeve 35, the hub sleeve 35 is rotatably mounted on the inner wall of the rear shell 4, the outer surface of the hub sleeve 35 is further fixed with the end face of the inflow ring 31 through the hub disc 34, the hub sleeve 35 is limited axially along the axial direction of the rotor part 5, and the stay angle of the hub sleeve 35 changes along with the rotating speed of the rotor part 5.

As shown in fig. 3, 4 and 6, the outflow ring 32 is a fixed component, no position change occurs in all operation processes of the fan, the inflow ring 31 needs to be correspondingly angularly adjusted when the rotation speed of the fan motor 6 changes, and after the inflow ring 31 and the outflow ring 32 relatively rotate on the circumference by one angle, the inlet setting angle of the guide vane 33 arranged between the inflow ring 31 and the outflow ring can correspondingly change, so that the guide vane 33 has larger rigidity or position limitation at the outlet position, and the outlet setting angle is ensured to be unchanged.

The rotor part 5 comprises a main shaft 51, a fixed sleeve 52, a centrifugal block 53, a sliding sleeve 54 and an axial translation sleeve 55, wherein the main shaft 51 is rotatably arranged on the inner wall of the rear shell 4, one end of the main shaft 51 is in transmission connection with a motor 6, the other end of the main shaft 51 is connected with an impeller 2, the main shaft 51 is respectively sleeved with the fixed sleeve 52 and the sliding sleeve 54, the fixed sleeve 52 is relatively fixed with the main shaft 51, the sliding sleeve 54 is in circumferential transmission and axial sliding connection with the main shaft 54, the sliding sleeve 54 and the fixed sleeve 52 are both hinged with the centrifugal block 53 through connecting rods, the outer surface of the sliding sleeve 54 radially extends and is sleeved with the axial translation sleeve 55 at the outer edge, the outer surface of the axial translation sleeve 55 is in threaded connection with the inner surface of the hub sleeve 35, and the sliding sleeve 54 is axially embedded with the axial translation sleeve 55 to limit and in circumferential rotation contact.

As shown in fig. 3 and 4, when the rotation speed of the main shaft 51 changes, the centrifugal block 53 has unequal centrifugal force, and pulls the sliding sleeve 54 to axially slide along the surface of the main shaft 51, the sliding sleeve 54 axially pushes the axial translation sleeve 55 to be at different axial positions, the axial translation sleeve 55 is in threaded engagement with the hub sleeve 35, and the hub sleeve 35 is pushed to rotate by an angle, so that the inflow ring 31 can also rotate by an angle, and the corresponding linkage relationship between the circumferential stay angle of the inflow ring 31 relative to the main shaft 51 and the rotation speed of the main shaft 51 is realized.

The guide vane 33 is a split sliding vane type at one side close to the inflow ring 31. As shown in fig. 7 and 8, the sliding sheets of the guide vane 33 may be slidably connected at the joint surface, and are stacked in turn like a folding fan, the stacking degree is based on the rotation of the inlet ring 31, the setting angles of the receiving air flows of the inlet positions of different stacking degrees are gradually changed, such a setting manner is in consideration of not occupying the torque of the main shaft 51, if an elastic guide sheet with larger rigidity is used, the inlet ring 31 is expected to return to the initial state by the elastic reaction force when staying at the expected angle, and these factors apply a reaction torque to the main shaft 51 at the sliding sleeve 54, consume a part of the power of the main shaft 51, and the guide vane 33 with different folding degrees does not need to maintain the force, only needs to apply force when changing.

The transmission of the rotor part 5 and the motor 6 is a belt transmission. The belt drive prevents fan overload, which must be considered especially in forward-curved blade fans.

The inlet end face of the inlet shell 1 is provided with a filter screen. Prevent the sundries in the plastic bag from being sucked in, and impact the blades of the impeller 2 and the blades in the guide vane 3 to influence the working efficiency.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Finally, it should be noted that: the foregoing description is only a preferred embodiment of the present invention, and the present invention is not limited thereto, but it is to be understood that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art, although the present invention has been described in detail with reference to the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A centrifugal fan capable of preventing gas backflow, which is characterized in that: centrifugal fan includes import shell (1), impeller (2), stator (3), backshell (4), rotor part (5), motor (6), spiral case (7), import shell (1) and backshell (4) are installed respectively to spiral case (7) both sides, rotor part (5) rotate and install on backshell (4) inner wall, rotor part (5) tip sets up impeller (2), rotor part (5) are connected with motor (6) transmission that sets up outside backshell (4), stator (3) are installed on spiral case (7) or backshell (4) inner wall, stator (3) are located impeller (2) periphery, stator (3) have the water conservancy diversion structure that links up the spiral angle of impeller (2) export laying angle and spiral case (7).

2. A centrifugal fan capable of preventing backflow of gas according to claim 1, wherein: the inlet shell (1) comprises a guide opening (11) and a connecting plate (12), the impeller (2) comprises a front cover plate (21), a working blade (22) and a rear cover plate,

the connecting plate (12) is fixedly connected with the volute (7), the central opening of the connecting plate (12) is connected with the guide opening (11), the guide opening (11) is in a reduced shape, one end with a small caliber is close to the impeller (2),

the front cover plate (21) and the rear cover plate are connected with a working blade (22), the central position of the rear cover plate is fixed with the rotor component (5),

an annular labyrinth groove (121) is formed in one side surface of the connecting plate (12) facing the impeller (2), a labyrinth embedding ring (211) is arranged at the end part of the front cover plate (21) facing the connecting plate (12), the labyrinth embedding ring (211) is embedded into the labyrinth groove (121), and the labyrinth embedding ring (211) and the labyrinth groove (121) take the central line of the rotor part (5) as an axis.

3. A centrifugal fan capable of preventing backflow of gas according to claim 1, wherein: the guide vane (3) comprises an inflow ring (31), an outflow ring (32) and guide vanes (33), wherein the inflow ring (31) and the outflow ring (32) respectively take the central line of the rotor part (5) as an axis, a plurality of guide vanes (33) which are radially arranged on the central line of the rotor part (5) are arranged between the inflow ring (31) and the outflow ring (32), the outlet setting angle of the guide vanes (33) is fixed, and the inlet setting angle of the guide vanes (33) is adjustable.

4. A centrifugal fan capable of preventing backflow of gas according to claim 3, wherein: the inlet setting angle of the guide vane (33) is interlocked with the rotational speed of the rotor member (5), and the inlet setting angle of the guide vane (33) is increased when the rotational speed of the rotor member (5) is increased.

5. The centrifugal fan capable of preventing gas backflow as in claim 4, wherein: the guide vane (3) further comprises a hub plate (34) and a hub sleeve (35), the hub sleeve (35) is rotatably mounted on the inner wall of the rear shell (4), the outer surface of the hub sleeve (35) is fixed with the end face of the inflow ring (31) through the hub plate (34), the hub sleeve (35) is limited along the axial direction of the rotor component (5), and the stay angle of the hub sleeve (35) changes along with the rotating speed of the rotor component (5).

6. The centrifugal fan capable of preventing gas backflow according to claim 5, wherein: the rotor component (5) comprises a main shaft (51), a fixed sleeve (52), a centrifugal block (53), a sliding sleeve (54) and an axial translation sleeve (55), wherein the main shaft (51) is rotatably arranged on the inner wall of a rear shell (4), one end of the main shaft (51) is in transmission connection with a motor (6), the other end of the main shaft (51) is connected with an impeller (2), the main shaft (51) is respectively sleeved with the fixed sleeve (52) and the sliding sleeve (54), the fixed sleeve (52) is relatively fixed with the main shaft (51), the sliding sleeve (54) is in circumferential transmission and axially sliding connection with the main shaft (54), the sliding sleeve (54) and the fixed sleeve (52) are hinged with the centrifugal block (53) through a connecting rod, the outer surface of the sliding sleeve (54) radially extends and is sleeved with the axial translation sleeve (55) at the outer edge, the outer surface of the axial translation sleeve (55) is in threaded connection with the inner surface of a hub sleeve (35), and the sliding sleeve (54) is axially embedded and limited and in circumferential rotation contact with the axial translation sleeve (55).

7. The centrifugal fan capable of preventing gas backflow as in claim 6, wherein: the guide vane (33) is of a split sliding sheet type at one side close to the inflow ring (31).

8. A centrifugal fan capable of preventing backflow of gas according to claim 1, wherein: the transmission of the rotor component (5) and the motor (6) is belt transmission.

9. A centrifugal fan capable of preventing backflow of gas according to claim 1, wherein: the inlet end face of the inlet shell (1) is provided with a filter screen.