CN113374706A

CN113374706A - Multistage centrifugal blower

Info

Publication number: CN113374706A
Application number: CN202110693126.1A
Authority: CN
Inventors: 铁善奎
Original assignee: Individual
Current assignee: Wuhan Chenxin Fluid Control Environmental Protection Equipment Co ltd
Priority date: 2021-06-22
Filing date: 2021-06-22
Publication date: 2021-09-10
Anticipated expiration: 2041-06-22
Also published as: CN113374706B

Abstract

The invention belongs to the technical field of blower production, and particularly relates to a multistage centrifugal blower which aims at the problems that the multistage centrifugal blower has multiple stages, a gas flow channel is long, the gas flow speed is uneven, the gas flow speed entering a next-stage impeller is seriously deviated from a designed value, the flow loss is large, and the efficiency of the blower is reduced. The invention arranges the impeller and the reflux ring to make the gas move in the shell in a straight-flow way, the gas flow channel is short, the gas flow velocity is more uniform, and the loss in the flow process is less.

Description

Multistage centrifugal blower

Technical Field

The invention relates to the technical field of blower production, in particular to a multistage centrifugal blower.

Background

The centrifugal blower is a constant pressure type blower, and has the advantages of continuous air supply, balanced operation, high efficiency, simple structure, low noise, small size and weight, few easily-damaged parts and the like compared with a positive displacement blower. The centrifugal blower is divided into a multi-stage centrifugal blower and a single-stage centrifugal blower. The single-stage fan utilizes high rotating speed to achieve required wind pressure and wind quantity, the flow channel of the multi-stage fan is short, the flow channel loss among multiple stages is reduced, the wind quantity is large, and the wind pressure of the fan is relatively small. The multistage fan increases the wind pressure by means of step-by-step pressurization, and is characterized by that the wind pressure is large, but the wind quantity is relatively small, and the outlet pressure and actual wind quantity of centrifugal fan are greatly influenced by inlet air temperature or density change, for a given air input, the pressure produced when the highest inlet air temperature (density is lowest) is lowest, and the required power is reduced along with the rise of inlet air temperature.

The multistage centrifugal blower has simple structure, easy manufacture and low cost, gradually replaces a Roots blower in recent years, and is widely applied to the fields of sewage treatment, aquaculture, smelting, material conveying and the like.

Disclosure of Invention

The invention provides a multistage centrifugal blower, aiming at solving the problems that in the prior art, the multistage centrifugal blower has multiple stages and a long gas flow channel, particularly the gas flow velocity of the gas flow at the outlet of the impeller of the previous stage is uneven after passing through a reflux device, the gas flow velocity entering the impeller of the next stage is seriously deviated from the designed value, the flow loss is large, and the efficiency of the blower is reduced.

In order to achieve the purpose, the invention adopts the following technical scheme: the utility model provides a multistage centrifugal blower, establishes the shell that the cavity is the cylinder in including, the circular port has been seted up at a side end face center of shell, and the embedded sealed bearing two that is equipped with of circular port, and has cup jointed the main shaft in the sealed bearing two, and the one end that the main shaft is located the shell is connected with the shaft coupling, and the shaft coupling is connected with driving motor two, the position that a side end wall of shell is located the top of circular port is provided with the gas transmission mouth, and a side end wall gas transmission mouth of shell, shell inner wall equidistance welding has a plurality of water conservancy diversion circle, and the center of water conservancy diversion circle is provided with the air inlet, and the position that the main shaft is located between two adjacent water conservancy diversion circles is provided with the wheel seat, and wheel seat outer wall is provided with the impeller, the shell inner wall is located the one end welding that the water conservancy diversion circle is close to the gas transmission mouth and has the backward flow ring, and backward flow ring equidistance is provided with a plurality of backward flow mouth.

Furthermore, the circumferential inner wall of the backflow ring is matched with the tail end of the outer wall of the adjacent wheel seat in size, a sealing device is arranged between the circumferential inner wall of the backflow ring and the tail end of the outer wall of the wheel seat, and the sealing device prevents gas from flowing out from a gap between the backflow ring and the wheel seat and prevents the gas from flowing unevenly.

Furthermore, one side of the flow guide ring close to the gas transmission port is arranged to be an inward-concave arc surface, one side of the flow guide ring far away from the gas transmission port is arranged to be a plane perpendicular to the side wall of the shell, and the flow guide ring of the arc surface plays a flow guide role, so that gas can stably enter a gas inlet and an impeller of the next-stage flow guide ring.

Further, one side end wall welding intake pipe of shell, and the upper end of intake pipe is provided with the flange, and intake pipe and gas transmission mouth intercommunication, and the inner wall upper portion joint of intake pipe has the filter screen, and the intake pipe inner wall installs the shock wave soot blower.

Furthermore, the air inlet pipe is set to be in a convergent shape with a wide upper part and a narrow lower part, a silencer is arranged on the outer wall of the upper part of the air inlet pipe, the air inlet pipe is made of a metal material with strong heat insulation performance, the air pressure of air entering the air inlet pipe is gradually increased through the air inlet pipe with the wide upper part and the narrow lower part, air can flow into the impeller to blow air, and the silencer reduces noise of the air inlet pipe.

Furthermore, the middle of the end face of one end, away from the gas transmission port, of the shell is provided with a tailstock, a first sealing bearing is installed in the tailstock, the first sealing bearing is connected with one end, away from a second driving motor, of the main shaft, the tailstock is made of metal materials with strong heat conductivity, a temperature sensor is installed on the outer wall of the tailstock, a water tank is welded at a position, above the tailstock, of the end face, close to the tailstock, of one side of the shell, condensed water is contained in the water tank, and a condensate pipe is fixed to the peripheral wall of the second sealing bearing.

Furthermore, the upper wall of the water tank is provided with a water filling port, the lower wall of the water tank is provided with a water discharging pipe, the lower end of the water discharging pipe is provided with a spray head, the lower part of the water discharging pipe is provided with an electromagnetic valve, and a control wire is connected between the electromagnetic valve and the temperature sensor.

Furthermore, a flow equalizing fan is arranged between the main shaft and the first flow guide ring close to the gas transmission port, the main shaft rotates to drive the flow equalizing fan to rotate, so that gas entering the flow guide ring through the gas transmission port can be distributed more uniformly, and the stability of the air blower is improved.

Furthermore, a base is arranged below the shell, a shock pad is arranged between the base and the shell, a mounting table is arranged at a position, below the second driving motor, of the base, the second driving motor is mounted on the mounting table, a supporting rod is arranged on one side, located at the mounting table, of the upper surface of the base, far away from the shell, of the upper surface of the base, a first driving motor is mounted at the upper end of the supporting rod, an output shaft of the first driving motor is connected with a rotating shaft through a second coupling, a cooling fan is fixed to the rotating shaft, and the height of the cooling fan is parallel to the two phases of the driving motor.

Further, the position that shell upper portion is close to the tailstock is provided with the outlet duct, and the inner wall of outlet duct is provided with pressure sensor, and the outlet duct is located the terminal top of the first wheel seat that is close to the tailstock, the pressure of pressure sensor survey outflow device's gas, the pressure that the air-blower was bubbled gas when stabilizing the work floats in the certain limit, whether the device breaks down is judged to the reading through pressure sensor, thereby make the trouble that the air-blower during operation staff can in time discover the air-blower and shut down the processing, prevent because the air-blower trouble causes the loss of operation in-process.

To sum up, the beneficial effect in this scheme is:

1. a multi-stage centrifugal blower, through the device of impeller and return ring set up, after the gas enters the outer casing from the gas transmission port, pass the guide ring and impeller and return ring sequentially, flow into the guide ring of the next stage through the return port on the return ring, repeat the previous cycle until the gas is blown out from the air outlet pipe, the guide ring that the gas is blown out from the impeller to flowing into the next stage of impeller and advancing is the convergent shape with wide front and narrow back, make the pressure intensity of the blown gas increase, promote the gas to flow to the next stage of impeller;

meanwhile, the windward side of the guide ring is an arc surface, when the gas has the trend of axial movement from the radial movement of the impeller to the outflow of the gas from the backflow port, the guide ring with the arc surface can reduce the energy loss generated by the conversion of the radial movement of the gas into the axial movement, and meanwhile, the gas performs direct-current movement in the shell, so that the gas circulation channel is short, the gas flow rate is more uniform, and the loss in the circulation process is less;

2. a multistage centrifugal blower is provided, through a device provided with a filter screen and a shock wave soot blower, after external gas enters an air inlet pipe, the filter screen can filter impurities in the gas, the impeller is prevented from being damaged by the impurities in the gas, the service life of the device is prolonged, the shock wave soot blower cleans adhesion substances on the inner wall of the air inlet pipe, the device is prevented from being used for a long time, and the problem that the air forms channeling on the inner wall of the air inlet pipe due to the impurities attached to the inner wall of the air inlet pipe and the like influences the blowing effect is avoided;

3. a multi-stage centrifugal blower, through the device of tailstock and water tank set up, when the main axis works for a long time, the sealed bearing one and sealed bearing two will produce the high heat because of friction nearby, the high temperature has certain influence to the performance of the sealed bearing, easy to cause the apparatus to damage, when the temperature sensor detects the temperature of the tailstock exceeds a certain value, the control electromagnetic valve opens, the condensed water in the water tank sprays to the tailstock through the shower nozzle and makes the temperature of the sealed bearing one reduce, lead to water to make the sealed bearing two cool continuously in the condensed water pipe at the same time, increase the life and safety in utilization of the device;

4. the utility model provides a multistage centrifugal blower, through the device of the driving motor one that sets up and radiator fan, when the air-blower was worked for a long time, driving motor two is sent out the scald owing to the function self that does not stop and pause, the part that high temperature damaged driving motor two easily leads to the device trouble, start driving motor one and radiator fan play the radiating action to driving motor two, extension device life and operation process's security, and simultaneously, the shock pad plays the cushioning effect, thereby prevent that the air-blower from making the base vibrations at the during operation shell vibrations, lead to driving motor two vibrations, lead to the main shaft to be damaged, influence the life of machine.

Drawings

FIG. 1 is a schematic structural view of a multi-stage centrifugal blower according to the present invention;

FIG. 2 is a cross-sectional view of a housing of a multi-stage centrifugal blower in accordance with the present invention;

FIG. 3 is a schematic structural view of the interior of a housing of a multi-stage centrifugal blower in accordance with the present invention;

FIG. 4 is a schematic structural diagram of a condensate pipe and a seal bearing II of the multi-stage centrifugal blower according to the present invention;

FIG. 5 is a schematic structural diagram of a water tank and a tailstock of a multistage centrifugal blower according to the present invention;

fig. 6 is a schematic structural diagram of a wheel seat and a return ring of a multistage centrifugal blower according to the present invention.

In the figure: 1-shell, 2-wheel seat, 3-impeller, 4-reflux port, 5-main shaft, 6-guide ring, 7-air inlet, 8-air outlet pipe, 9-pressure sensor, 10-water tank, 11-temperature sensor, 12-sealing bearing I, 13-tailstock, 14-shock pad, 15-base, 16-support rod, 17-mounting table, 18-driving motor I, 19-cooling fan, 20-driving motor II, 21-coupler, 22-flow equalizing fan, 23-reflux ring, 24-silencer, 25-air inlet pipe, 26-filter screen, 27-shock wave soot blower, 28-flange, 29-spray head, 30-air inlet, 31-sealing bearing II, 32-condensate pipe, 33-water filling port, 34-condensed water, 35-water discharging pipe and 36-electromagnetic valve.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

In the description of the present invention, it is to be understood that the terms "above," "below," "side," "center," "midpoint," "upper," "top," "bottom," "inner," "outer," and the like are used in the orientations and positional relationships indicated in the drawings for the purpose of convenience and simplicity of description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting.

Example 1

Referring to fig. 1-3 and fig. 6, a multistage centrifugal blower comprises a housing 1 with a cylindrical cavity therein, a circular hole is formed in the center of one side end face of the housing 1, a sealing bearing II 31 is embedded in the circular hole, a spindle 5 is sleeved in the sealing bearing II 31, one end of the spindle 5 positioned on the housing 1 is connected with a coupler 21, the coupler 21 is connected with a driving motor II 20, an air transmission port 30 is arranged at a position of one side end wall of the housing 1 positioned above the circular hole, the air transmission port 30 is arranged at one side end wall of the housing 1, a plurality of flow guide rings 6 are welded on the inner wall of the housing 1 at equal intervals, an air inlet 7 is arranged in the center of each flow guide ring 6, a wheel seat 2 is arranged at a position between two adjacent flow guide rings 6 of the spindle 5, an impeller 3 is arranged on the outer wall of the wheel seat 2, a backflow ring 23 is welded at one end of the inner wall of the housing 1 positioned on the flow guide ring 6 close to the air transmission port 30, and the reflux ring 23 is provided with a plurality of reflux ports 4 at equal intervals.

In the invention, the circumferential inner wall of the backflow ring 23 is matched with the tail end of the outer wall of the adjacent wheel seat 2 in size, and a sealing device is arranged between the circumferential inner wall of the backflow ring 23 and the tail end of the outer wall of the wheel seat 2, so that the sealing device prevents gas from flowing out from a gap between the backflow ring 23 and the wheel seat 2 and prevents the uneven flow rate of the gas.

In the invention, an air inlet pipe 25 is welded on the end wall of one side of the shell 1, a flange 28 is arranged at the upper end of the air inlet pipe 25, the air inlet pipe 25 is communicated with an air delivery port 30, a filter screen 26 is clamped at the upper part of the inner wall of the air inlet pipe 25, and a shock wave soot blower 27 is arranged on the inner wall of the air inlet pipe 25.

In the invention, one side of the guide ring 6 close to the gas transmission port 30 is arranged to be an inward concave arc surface, one side of the guide ring 6 far away from the gas transmission port 30 is arranged to be a plane vertical to the side wall of the shell 1, and the guide ring 6 with the arc surface plays a role in guiding, so that gas can stably enter the gas inlet 7 of the guide ring 6 at the next stage and the impeller 3.

In the invention, the flow equalizing fan 22 is arranged between the air transmission port 30 and the first flow guiding ring 6 close to the air transmission port 30 of the main shaft 5, and the main shaft 5 rotates to drive the flow equalizing fan 22 to rotate, so that the gas entering the flow guiding ring 6 through the air transmission port 30 can be distributed more uniformly, and the stability of the blower is improved.

In the invention, the air inlet pipe 25 is in a convergent shape with a wide upper part and a narrow lower part, the silencer 24 is arranged on the outer wall of the upper part of the air inlet pipe 25, the air inlet pipe 25 is made of a metal material with strong heat insulation property, the air pressure of air entering the air inlet pipe 25 is gradually increased by the air inlet pipe 25 with the wide upper part and the narrow lower part, the air flows into the impeller 3 to blow air, and the silencer 24 reduces the noise of the air inlet pipe 25

According to the invention, the upper part of the shell 1 is provided with the air outlet pipe 8 close to the tail seat 13, the inner wall of the air outlet pipe 8 is provided with the pressure sensor 9, the air outlet pipe 8 is positioned above the tail end of the first wheel seat 2 close to the tail seat 13, the pressure sensor 9 measures the pressure of the gas flowing out of the device, the pressure of the gas blown out of the device floats within a certain range when the blower works stably, whether the device breaks down or not is judged through the reading of the pressure sensor 9, so that a worker can find the fault of the blower in time to stop the blower when the blower works, and the loss in the operation process caused by the fault of the blower is prevented.

The working principle is as follows: after the outside air enters the air inlet pipe 25, the filter screen 26 can filter impurities in the air to prevent the impurities in the air from damaging the impeller 3, so that the service life of the device is prolonged, the shock wave soot blower 27 cleans adhesion objects on the inner wall of the air inlet pipe 25 to prevent the device from being used for a long time, and the inner wall of the air inlet pipe 25 is adhered with impurities to cause the problems that the air forms channeling on the inner wall of the air inlet pipe 25 and the like to influence the blast effect; when the gas enters the shell 1 from the gas transmission port 30, the gas passes through the guide ring 6, the impeller 3 and the return ring 23 in sequence, flows into the guide ring 6 of the next stage through the return port 4 on the return ring 23, repeats the previous cycle until the gas is blown out from the gas outlet pipe 8, the guide ring 6 which is blown out from the impeller 3 and flows into the impeller 3 of the next stage and passes through the front is in a convergent shape with wide front and narrow back, increases the pressure of the blown gas, promotes the gas to flow to the impeller 3 of the next stage, meanwhile, the windward side of the guide ring 6 is a cambered surface, when the gas has the trend of axial movement from the radial movement of the impeller 3 to the outflow from the return port 4, the cambered guide ring 6 can reduce the energy loss generated by converting the radial motion of the gas into the axial motion, meanwhile, gas moves in the shell 1 in a straight-flow mode, a gas flow channel is short, the gas flow velocity is more uniform, and the loss in the flow process is less.

Example 2

Referring to fig. 1 to 6, in this embodiment, compared with embodiment 1, the multistage centrifugal blower further includes a tailstock 13 disposed in the middle of an end surface of the housing 1 far away from the gas transmission port 30, a first sealing bearing 12 is installed in the tailstock 13, the first sealing bearing 12 is connected to an end of the spindle 5 far away from the second driving motor 20, the tailstock 13 is made of a metal material with high thermal conductivity, a temperature sensor 11 is installed on an outer wall of the tailstock 13, a water tank 10 is welded to a position of the end surface of the housing 1 near the tailstock 13 and above the tailstock 13, condensed water 34 is installed in the water tank 10, and a condensed water pipe 32 is fixed to a peripheral wall of the second sealing bearing 31.

In the invention, the upper wall of the water tank 10 is provided with a water filling port 33, the lower wall of the water tank 10 is provided with a water drainage pipe 35, the lower end of the water drainage pipe 35 is provided with a spray head 29, the lower part of the water drainage pipe 35 is provided with an electromagnetic valve 36, a controller is connected between the electromagnetic valve 36 and the temperature sensor 11, the temperature sensor 11 transmits an electric signal to the controller, when the temperature sensor 11 detects that the temperature of the tailstock 13 is overhigh, the controller obtains a corresponding electric signal, the electromagnetic valve 36 is controlled to be opened, water in the water tank 10 is discharged, and the tailstock 13 is cooled.

In the invention, a base 15 is arranged below a shell 1, a shock absorption pad 14 is arranged between the base 15 and the shell 1, a mounting table 17 is arranged at a position of the base 15 below a second driving motor 20, the second driving motor 20 is mounted on the mounting table 17, a support rod 16 is arranged on one side, away from the shell 1, of the mounting table 17 on the upper surface of the base 15, a first driving motor 18 is mounted at the upper end of the support rod 16, an output shaft of the first driving motor 18 is connected with a rotating shaft through a second coupling, a radiating fan 19 is fixed on the rotating shaft, the height of the radiating fan 19 is flush with that of the second driving motor 20, the shock absorption pad 14 plays a shock absorption role, and the situation that the shell vibrates to enable the base 15 to vibrate when an air blower works and the second driving motor 20 vibrates to cause the main shaft 5 to be damaged to influence the service life of a machine and the safety of the device in the operation process is prevented.

The working principle is as follows: when the main shaft 5 works for a long time, high heat is generated near the first sealed bearing 12 and the second sealed bearing 31 due to friction, the high temperature has certain influence on the performance of the sealed bearings, and equipment damage is easily caused, when the temperature sensor 11 detects that the temperature of the tailstock 13 exceeds a certain value, the electromagnetic valve 36 is controlled to be opened, condensed water 34 in the water tank 10 is sprayed onto the tailstock 13 through the spray head 29, so that the temperature of the first sealed bearing 12 is reduced, meanwhile, water is continuously introduced into the condensed water pipe 32, so that the second sealed bearing 31 is cooled, and the service life and the use safety of the device are prolonged; when the blower works for a long time, the second driving motor 20 is heated due to continuous operation, parts of the second driving motor 20 are easily damaged due to high temperature, so that the device is in failure, the first driving motor 18 and the cooling fan 19 are started to perform a cooling effect on the second driving motor 20, and the service life of the device and the safety of the operation process are prolonged.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. A multistage centrifugal blower comprises a shell (1) with a cylindrical inner cavity, a circular hole is formed in the center of one side end face of the shell (1), a sealing bearing II (31) is embedded in the circular hole, a main shaft (5) is sleeved in the sealing bearing II (31), one end, located on the shell (1), of the main shaft (5) is connected with a shaft coupler (21), the shaft coupler (21) is connected with a driving motor II (20), a gas transmission port (30) is formed in the position, located above the circular hole, of one side end wall of the shell (1), the gas transmission port (30) is formed in one side end wall of the shell (1), the multistage centrifugal blower is characterized in that a plurality of flow guide rings (6) are welded on the inner wall of the shell (1) in an equidistant mode, a gas inlet (7) is formed in the center of each flow guide ring (6), and a wheel seat (2) is arranged in the position, located between two adjacent flow guide rings (6), of the main shaft (5), and wheel seat (2) outer wall is provided with impeller (3), shell (1) inner wall is located one end welding that water conservancy diversion circle (6) is close to gas transmission mouth (30) and has backflow ring (23), and backflow ring (23) equidistance is provided with a plurality of backward flow mouth (4).

2. A multistage centrifugal blower according to claim 1, characterised in that the circumferential inner wall of the return ring (23) is dimensioned to fit the outer wall end of the adjacent wheel holder (2), and that sealing means are provided between the circumferential inner wall of the return ring (23) and the outer wall end of the wheel holder (2).

3. The multistage centrifugal blower according to claim 1, wherein the side of the flow guiding ring (6) close to the air transfer port (30) is arranged as an inwardly concave arc, and the side of the flow guiding ring (6) far from the air transfer port (30) is arranged as a plane perpendicular to the side wall of the casing (1).

4. The multistage centrifugal blower according to claim 1, wherein an air inlet pipe (25) is welded to one side end wall of the shell (1), a flange (28) is arranged at the upper end of the air inlet pipe (25), the air inlet pipe (25) is communicated with the air delivery port (30), a filter screen (26) is clamped on the upper portion of the inner wall of the air inlet pipe (25), and a shock wave soot blower (27) is installed on the inner wall of the air inlet pipe (25).

5. The multistage centrifugal blower according to claim 4, wherein the intake duct (25) is formed in a convergent shape having a wide upper portion and a narrow lower portion, and a silencer (24) is provided on an outer wall of an upper portion of the intake duct (25), and the intake duct (25) is made of a metal material having a high heat insulating property.

6. The multistage centrifugal blower according to claim 1, wherein a tailstock (13) is disposed in a middle portion of an end face of the casing (1) far away from the gas transmission port (30), a first seal bearing (12) is mounted in the tailstock (13), the first seal bearing (12) is connected with one end of the spindle (5) far away from the second drive motor (20), the tailstock (13) is made of a metal material with high thermal conductivity, a temperature sensor (11) is mounted on an outer wall of the tailstock (13), a water tank (10) is welded to a position, above the tailstock (13), of an end face of one side, close to the tailstock (13), of the casing (1), condensed water (34) is filled in the water tank (10), and a condensed water pipe (32) is fixed to a peripheral wall of the second seal bearing (31).

7. The multistage centrifugal blower according to claim 6, wherein the upper wall of the water tank (10) is provided with a water filling port (33), the lower wall of the water tank (10) is provided with a water discharge pipe (35), the lower end of the water discharge pipe (35) is provided with a spray head (29), the lower part of the water discharge pipe (35) is provided with an electromagnetic valve (36), and a control wire is connected between the electromagnetic valve (36) and the temperature sensor (11).

8. A multistage centrifugal blower according to claim 1, characterised in that a flow equalizing fan (22) is arranged between the air transfer opening (30) and the first flow guiding ring (6) adjacent to the air transfer opening (30) in the main shaft (5).

9. The multistage centrifugal blower according to claim 1, wherein a base (15) is arranged below the casing (1), a shock absorption pad (14) is arranged between the base (15) and the casing (1), an installation table (17) is arranged at a position of the base (15) below the second driving motor (20), the second driving motor (20) is installed on the installation table (17), a support rod (16) is arranged on one side, away from the casing (1), of the upper surface of the base (15) on the installation table (17), a first driving motor (18) is installed at the upper end of the support rod (16), an output shaft of the first driving motor (18) is connected with a rotating shaft through a second coupling, a cooling fan (19) is fixed on the rotating shaft, and the height of the cooling fan (19) is flush with the second driving motor (20).

10. The multistage centrifugal blower according to claim 1, wherein an air outlet pipe (8) is arranged at the upper part of the shell (1) close to the tailstock (13), a pressure sensor (9) is arranged on the inner wall of the air outlet pipe (8), and the air outlet pipe (8) is positioned above the end of the first wheel seat (2) close to the tailstock (13).