Air suspension centrifugal blower avoiding large amplitude airflow oscillation and processing technology thereof

Abstract

The application discloses an air suspension centrifugal blower capable of avoiding large-amplitude airflow oscillation, comprising a centrifugal blower box, a high-speed permanent magnet motor arranged in the box, an impeller connected with an output shaft of the high-speed permanent magnet motor and located in a volute, and a suction chamber connected with the middle part of the volute; an adjusting mechanism for adjusting a blade tip clearance is arranged on a wheel shaft of the impeller. The application further discloses a processing technology of the air suspension centrifugal blower capable of avoiding large-amplitude airflow oscillation, wherein, after dynamic balance testing of the wheel shaft and the impeller, a radial bearing and an axial bearing are assembled; the impeller is assembled into the volute and installed on the high-speed permanent magnet motor; soundproof cotton is installed on the inner wall of the box, and the high-speed permanent magnet motor is installed into the box. The application can effectively control the blade tip clearance to prevent surge, especially when the flow is small, the blade tip clearance is reduced, and the back pressure at the outlet of the impeller is increased; the flow entering the blade of the suction chamber is away from the surge zone, and the surge is effectively prevented.

Description

[0001] This application is a divisional application of application number: 202310436116.9, patent name: Anti-surge air suspension centrifugal blower and its processing technology, application date: April 23, 2023. TECHNICAL FIELD

[0002] The present application relates to an air suspension centrifugal blower that avoids large amplitude airflow oscillation and a processing technology thereof. BACKGROUND

[0003] The air suspension blower is a kind of blower in which air is floated by a high-pressure gas film formed between the rotor and the foil bearing surface under the high-speed rotation of the rotor. According to the principle of converting kinetic energy into potential energy, the gas is accelerated by the high-speed rotating impeller, then decelerated, the flow direction is changed, and the kinetic energy is converted into potential energy. The pressure increase mainly occurs in the impeller, and then in the diffuser process.

[0004] When the flow rate is small to a certain value, periodic, low-frequency, large-amplitude airflow oscillation phenomenon will occur in the fan system, which is called "surge". When surge occurs, the normal flow rule is completely broken, and the severe vibration will cause the blower to be severely damaged in a short time. The surge flow line of the air suspension centrifugal blower is a curve, which changes with pressure, medium and other vibration conveyor factors; the design concept of air suspension centrifugal blower is to adopt low noise and anti-vibration technology, and its running noise is generally 75-80db under normal operation. When the equipment surges, the most common problem factors are control system failure and operator misoperation. For the reasons of surge, the machine equipment needs to be checked one by one. When the air suspension centrifugal blower surges, it will cause the fan blade to break or the mechanical parts to be damaged, so it is strictly forbidden to run the fan under the condition of surge. When the surge problem occurs, the main characteristics are: low-frequency roaring sound or panting sound, motor current fluctuation, and the surge flow line of the fan is a curve. The possible reasons are that the outlet valve opening is too small, or the outlet return main air line is too small. These problems may also cause the surge to occur, and the specific performance is that the current changes greatly, the outlet check valve emits abnormal sound, and there is no other obvious characteristics.

[0005] At present, for surge, generally take the anti-surge control to achieve unmanned operation, such as the patent with publication number CN111594478B: a magnetic suspension centrifugal blower anti-surge control method based on big data, including a large number of actual operation data after the selection principle-mutual exclusion principle to construct data model, then through data analysis to form multidimensional data, then the surge point of the multidimensional data is composed into the surge area. For a large number of the same type of magnetic suspension blower, continuously collect multidimensional data during its factory test and field operation and record, analyze, draw the fan surge area with data as the core, that is, the anti-surge control can be realized; the construction of the anti-surge model in the early stage can draw a rough surge area with a small amount of three-dimensional data, and with the increase of the data amount and dimension in the later period, the surge area will be more and more accurate; it is a growing and trainable anti-surge model. There are also existing technologies that make changes to the shape of the impeller blade and the shape of the blade disc structure to correct the airflow angle of the impeller rotation direction, thereby reducing the rotation angle of the airflow entering the impeller diffuser area, increasing the rotation stall margin, and ultimately effectively improving the anti-surge ability of the centrifugal blower, such as the patent with publication number CN209959559U: a centrifugal blower impeller with anti-surge ability and a centrifugal blower thereof, the centrifugal blower impeller is integrally cast into a impeller disc and a plurality of blades located on the impeller disc by an aluminum alloy material, each blade is distributed on the inner periphery of the impeller disc, the impeller disc is provided with a rotating shaft hole fixedly connected with the rotating main shaft of the centrifugal blower, an axial air inlet communicated with the air inlet channel, and a radial air inlet communicated with the air outlet channel; wherein each blade is a backward blade with large backward sweep, the outlet angle of the blade ranges from 60 to 80 degrees, and the number of blades is 12; the outer periphery of the impeller disc close to the axial air inlet is provided with a sealing surface in the form of a sawtooth labyrinth. Tang Mao of Nanjing University of Aeronautics and Astronautics published a master's degree thesis "Research on Magnetic Suspension Surge Control of Centrifugal Compressor" to prevent surge by controlling the thrust bearing to change the tip clearance between the impeller and the volute; since it is a magnetic suspension centrifugal blower, the control of the tip clearance can be realized by controlling the axial magnetic bearing, but it is difficult to realize in an air suspension centrifugal blower. In addition, from the existing technology, most of the ways to solve the anti-surge are realized by control-regulation, and few are realized by changing the structure. SUMMARY

[0006] The purpose of the present application is to overcome the defects in the prior art, provide an air suspension centrifugal blower that can effectively prevent surge by controlling the tip clearance, especially reducing the tip clearance at low flow rate to increase the outlet back pressure of the impeller; realize that no matter at high flow rate or low flow rate, the flow rate finally reaching the blade is large, so that the flow rate entering the blade of the suction chamber is out of the surge area, effectively preventing surge.

[0007] To achieve the above objectives, the technical solution of this invention is to design an air-suspended centrifugal blower that avoids large-amplitude airflow oscillations. The blower includes a centrifugal blower housing, a high-speed permanent magnet motor housed within the housing, an impeller connected to the output shaft of the high-speed permanent magnet motor within a volute, an intake chamber connected to the middle of the volute, and an air outlet pipe connected to the outlet of the volute extending beyond the top surface of the housing. An air inlet filter is installed on the side of the housing facing the air inlet of the intake chamber. An adjustment mechanism for adjusting the blade tip clearance is provided on the impeller shaft. The adjustment mechanism includes a bottom cylinder sleeved around the impeller shaft, the bottom cylinder being fixedly connected to the impeller shaft. A ring of elastic blocks is provided on the bottom cylinder, arranged in a circular array around the rotation axis of the bottom cylinder. Blind hole-shaped grooves are provided on the outer surface of the bottom cylinder corresponding to the positions of the elastic blocks. An upper cylinder is sleeved around the bottom cylinder, the upper end face of which is fixedly connected to the bottom surface of the blades. By installing an adjustment mechanism on the impeller shaft to regulate the tip clearance, the tip clearance can be effectively controlled to prevent surge, especially at low flow rates, reducing the tip clearance and increasing the impeller outlet back pressure. This ensures that regardless of whether the intake flow is high or low (referring to the flow rate at the inlet of the suction chamber), the final flow reaching the blades is high, causing the flow entering the suction chamber blades to leave the surge zone and effectively preventing surge. The impeller includes blades and a shaft. The blades have shaft holes adapted to the shaft, and straight keys are installed in the shaft holes for axial sliding of the blades. By excavating grooves on the outer surface of the bottom cylinder and installing elastic blocks (which can be made of a trapezoidal material such as rubber), the upper cylinder can press down on the elastic blocks at high flow rates, causing the upper cylinder to move downwards appropriately. Conversely, at low flow rates, the upper cylinder moves upwards appropriately due to the elastic force of the blocks, reducing the tip clearance at low flow rates and causing the flow entering the suction chamber blades to leave the surge zone, effectively preventing surge.

[0008] A further technical solution is to connect an air outlet branch pipe to the air outlet duct, with one end of the air outlet branch pipe extending beyond the top surface of the housing.

[0009] A further technical solution is that the enclosure is made of carbon steel, the inner wall of the enclosure is lined with sound insulation cotton, and the surface of the enclosure is covered with a baked paint anti-corrosion layer.

[0010] Several weight-reducing grooves are provided on the inner wall of the shaft hole, arranged in a circular array around the center line of the shaft hole. By providing several hollow weight-reducing grooves on the inner wall of the shaft hole, this structure effectively reduces the weight of the impeller without affecting its installation, positioning, or structural strength. This results in significant reductions in energy consumption, rotational inertia, and component costs.

[0011] The present invention also provides a process for manufacturing an air-suspended centrifugal blower that avoids large-amplitude airflow oscillations, comprising the following sequential process steps:

[0012] S1: After dynamic balance test of the wheel shaft and impeller, the radial bearing and axial bearing are assembled;

[0013] S2: The impeller is assembled into the volute, and after the impeller is installed on the high-speed permanent magnet motor, performance test and vibration test are carried out;

[0014] S3: The air outlet pipe of the volute is installed on the volute, the fixed sound insulation cotton is installed on the inner wall of the box, and then the high-speed permanent magnet motor is installed in the box, and then the whole machine performance test is carried out. Generally, a vent valve is also installed on the air outlet pipe.

[0015] Since the air suspension centrifugal blower adopts air suspension bearing, it does not need a lubricating oil circulation system. The high-speed motor is directly connected with the impeller, and does not need a speed increasing gear and a shaft coupling. The air suspension centrifugal blower does not need a gear box speed increaser and a shaft coupling, and the impeller is directly connected with the motor and is driven by the high-speed motor. The motor uses a frequency converter to adjust the speed. When the motor reaches a certain rotating speed, the shaft is suspended on the active air bearing controller. Since there is no physical contact and no lubricating oil system, the air suspension centrifugal blower has the characteristics of high efficiency, energy saving, low noise, reliable operation and long-term maintenance-free.

[0016] The advantages and beneficial effects of the present application are that the control of the blade tip clearance can effectively prevent surge, especially the blade tip clearance is reduced at small flow, and the outlet back pressure of the impeller is improved; and no matter at large flow or small flow, the flow finally reaches the blade, so that the flow entering the blade of the suction chamber is out of the surge area, and the surge is effectively prevented.

[0017] The elastic metal cylinder is made of aluminum alloy Al-5083, which has better elasticity. At large flow, it has certain shrinkage deformation, so that the blade tip clearance meets the normal needs. At small flow, it freely stretches, reduces the blade tip clearance, improves the outlet back pressure of the impeller, and effectively prevents the surge at small flow and high pressure ratio.

[0018] Through the air volume sensor built in the blower, the mass flow of the inlet cross section of the air inlet chamber of the blower is monitored to control the sliding distance of the magnetic metal cylinder to achieve more accurate control (i.e. more accurate control of the blade tip clearance), so that the blade tip clearance is controllable at different flow, the outlet back pressure of the impeller is effectively improved, the problem of low inlet flow is solved in time, the flow entering the blade of the suction chamber is out of the surge area, and the surge is effectively prevented.

[0019] By digging grooves on the outer surface of the bottom cylinder and cooperating with the elastic blocks (which can be made of materials with elasticity such as rubber blocks in the form of trapezoidal bodies), the elastic blocks are pressed down by the upper cylinder at large flow, and the upper cylinder is appropriately moved downward. At small flow, the upper cylinder is appropriately moved upward due to the elastic force of the elastic blocks, which reduces the blade tip clearance at small flow, so that the flow entering the blade of the suction chamber is out of the surge area, and the surge is effectively prevented.

[0020] The application is characterized in that a plurality of hollow weight-reducing grooves are arranged on the inner wall of the shaft hole of the wheel shaft, which effectively reduces the weight of the impeller without affecting the installation position and structural strength of the impeller, and has remarkable effects of reducing energy consumption, rotational inertia and part cost.

[0021] The air suspension centrifugal blower adopts air suspension bearing, and does not need lubricating oil circulation system. The high-speed motor is directly connected with the impeller, and does not need speed increasing gear and shaft coupling. The air suspension centrifugal blower does not need gear box speed increaser and shaft coupling, and the impeller is directly connected with the motor and is driven by the high-speed motor. The motor adopts frequency converter to adjust speed. When the motor reaches a certain rotating speed, the shaft is suspended on the active air bearing controller. Because there is no physical contact and no lubricating oil system, the air suspension centrifugal blower has the characteristics of high efficiency, energy saving, low noise, reliable operation and long-term maintenance-free. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Fig. 1 is a schematic diagram of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application;

[0023] Figure 2 Fig. 2 is a schematic diagram of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application; Figure 1 Fig. 3 is a schematic diagram of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application after removing the side surface of the box;

[0024] Figure 3 Fig. 4 is a schematic diagram of another view of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application; Figure 2 Fig. 5 is a schematic diagram of another view of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application;

[0025] Figure 4 Fig. 6 is a schematic diagram of another view of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application; Figure 2 Fig. 7 is a sectional view along the rotating axis of the suction chamber of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application;

[0026] Figure 5 Fig. 8 is a schematic diagram of the enlarged view of the suction chamber part of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application; Figure 4 Fig. 9 is a schematic diagram of the enlarged view of the part near the middle blade and the elastic metal cylinder part of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application;

[0027] Figure 6 Fig. 10 is a schematic diagram of the enlarged view of the part near the middle blade and the elastic metal cylinder part of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application; Figure 5 Fig. 11 is a schematic diagram of the enlarged view of the part near the middle blade and the elastic metal cylinder part of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application;

[0028] Figure 7 Fig. 12 is a schematic diagram of the enlarged view of the part near the middle blade and the elastic metal cylinder part of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application; Figure 2 Fig. 13 is a schematic diagram of the enlarged view of the part near the middle blade and the elastic metal cylinder part of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application;

[0029] Figure 8 Fig. 14 is a sectional view of the impeller along the direction perpendicular to the wheel shaft of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application;

[0030] Figure 9 Fig. 15 is a surge and choke curve of the embodiment one of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application;

[0031] Figure 10 Fig. 16 is a schematic diagram of the high-speed permanent magnet motor, the volute and the suction chamber part of the embodiment two of the air suspension centrifugal blower for avoiding large-amplitude airflow oscillation according to the present application;

[0032] Figure 11 is a sectional view of Figure 10 ;

[0033] Figure 12 is a partial enlarged schematic view of Figure 11 ;

[0034] Figure 13 is a schematic diagram of the principle of Figure 10 ;

[0035] Figure 14 is an enlarged schematic view of the upper end portion of Figure 13 ;

[0036] Figure 15 is a schematic diagram of the blade and adjusting mechanism in the third embodiment of the present application;

[0037] Figure 16 is an exploded schematic view of Figure 15 ;

[0038] Figure 17 is a schematic diagram of the suction chamber and flow increasing device portion in the fourth embodiment of the present application.

[0039] In the figure: 1, box; 2, high-speed permanent magnet motor; 3, volute; 4, suction chamber; 5, air outlet pipe; 6, blade; 7, elastic metal cylinder; 8, air outlet branch pipe; 9, weight-reducing groove; 10, magnetic metal cylinder; 11, magnetic shell section; 12, permanent magnet block; 13, hydraulic cylinder; 14, controller; 15, air volume sensor; 16, bottom cylinder; 17, elastic block; 18, upper cylinder; 19, communication pipe; 20, blower; 21, on-off valve; 22, flow sensor. DETAILED DESCRIPTION

[0040] The specific embodiments of the present application will be further described below in conjunction with the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application. Example 1

[0041] As shown in Figures 1 to 9 , for the convenience of illustration, Figure 4The present application is an air suspension centrifugal blower which avoids large amplitude airflow oscillation. The blower comprises a centrifugal blower box 1, a high-speed permanent magnet motor 2 arranged in the box 1, an impeller connected to the output shaft of the high-speed permanent magnet motor 2 and located in a volute 3, a suction chamber 4 connected to the middle part of the volute 3, an air outlet pipe 5 connected to the air outlet of the volute 3 and extending beyond the top surface of the box 1, and an air inlet filter arranged on the side of the box 1 facing the air inlet of the suction chamber 4. An adjusting mechanism for adjusting the blade tip clearance is arranged on the shaft of the impeller. The impeller comprises blades 6 and a shaft, and the blades 6 are provided with shaft holes which are adapted to the shaft. Straight keys for the axial sliding of the blades 6 are arranged on the shaft holes. The adjusting mechanism comprises an elastic metal cylinder 7 arranged on the shaft, and the back surfaces of the blades 6 are fixedly connected to the elastic metal cylinder 7. The air outlet pipe 5 is connected to an air outlet branch pipe 8 which also extends beyond the top surface of the box 1. The box 1 is made of carbon steel, and the inner wall of the box 1 is provided with soundproof cotton. The surface of the box 1 is provided with a baked paint anticorrosive layer. A plurality of weight-reducing grooves 9 are arranged on the inner wall of the shaft hole in a ring shape and along the center line of the shaft hole.

[0042] The process for processing the air suspension centrifugal blower which avoids large amplitude airflow oscillation comprises the following process steps which are performed in sequence:

[0043] S1: After the dynamic balance test of the shaft of the impeller and the impeller, the radial bearing and the axial bearing are assembled.

[0044] S2: The impeller is assembled into the volute 3, and the performance test and the vibration test are performed after the impeller is installed on the high-speed permanent magnet motor 2.

[0045] S3: The air outlet pipe 5 of the volute 3 is installed on the volute 3, the soundproof cotton is installed on the inner wall of the box 1, the high-speed permanent magnet motor 2 is installed in the box 1, and then the performance test of the whole machine is performed.

[0046] The working principle is as follows: the elastic metal cylinder is made of aluminum alloy Al-5083 and has good elasticity. When the air flow is large, the elastic metal cylinder is deformed to a certain extent, so that the blade tip clearance meets the normal requirements. When the air flow is small, the elastic metal cylinder freely stretches, the blade tip clearance is reduced, the back pressure at the outlet of the impeller is increased, and the surge at small flow and high pressure ratio is effectively prevented. When the air flow is large, the elastic metal cylinder is deformed to a certain extent (larger) due to the large pressure, so that the blade tip clearance is increased. When the air flow is small, the elastic metal cylinder is deformed to a small extent due to the small pressure, so that the blade tip clearance is small. The blade tip clearance is adjusted through the structural improvement, which is simple and saves various control modes and processes. Example Two

[0047] The difference between the example two and the example one is that, as shown in Figures 10 to 14 for the convenience of illustration, Figure 10The impeller comprises the blades 6 and a wheel shaft, the shaft hole is arranged on the blade 6 and is matched with the wheel shaft, and the straight key for the axial sliding of the blade 6 is arranged on the shaft hole; the adjusting mechanism comprises a magnetic metal cylinder 10 sleeved on the wheel shaft, and the leeward surface of the blade 6 is fixedly connected to the magnetic metal cylinder 10; the high-speed permanent magnet motor 2 adopts a magnetic shell section 11 at the position corresponding to the magnetic metal cylinder 10 of the motor shell, the permanent magnet block 12 is arranged on the outer surface of the magnetic shell section 11, the permanent magnet block 12 is connected with a transmission mechanism, and the transmission mechanism is electrically connected with a controller 14; the transmission mechanism adopts a hydraulic cylinder 13, the exposed end of the piston rod of the hydraulic cylinder 13 is fixedly connected with the permanent magnet block 12; and the controller 14 is electrically connected with an air volume sensor 15 built in the air suspension centrifugal blower.

[0048] The working principle is as follows: according to the air volume sensor built in the blower, the mass flow of the inlet section of the inlet chamber of the blower is monitored to control the sliding distance of the magnetic metal cylinder to realize more accurate control (that is, more accurate control of the tip clearance), so that the tip clearance is controllable at different flow rates, the outlet back pressure of the impeller is effectively improved, the problem of low inlet flow rate is solved in time, the flow rate at the blade of the suction chamber leaves the surge zone, and the surge is effectively prevented. Specifically, the flow rate information at the inlet (or the air volume information) is transmitted to the controller by the air volume sensor, the controller controls the action of the hydraulic cylinder, the permanent magnet block slides upwards or downwards to adjust the tip clearance. Through the improvement of the structure, the controller controls the external permanent magnet block to realize the movement of the magnetic metal cylinder below the blade to adjust the tip clearance, so that the flow rate at the blade of the suction chamber leaves the surge zone, and the surge is effectively prevented. Embodiment three

[0049] Different from the embodiment one, as shown in Figure 15 , Figure 16 , the adjusting mechanism comprises a bottom cylinder 16 sleeved outside the wheel shaft of the blade 6, the bottom cylinder 16 is fixedly connected with the wheel shaft of the blade 6, a circle of elastic blocks 17 is arranged on the bottom cylinder 16, the circle of elastic blocks 17 is arranged in a ring array with the rotation axis of the bottom cylinder 16 as the center, the blind hole-shaped grooves are arranged on the outer surface of the bottom cylinder 16 corresponding to the positions of the elastic blocks 17, and an upper cylinder 18 is sleeved outside the bottom cylinder 16, the upper end surface of the upper cylinder 18 is fixedly connected with the bottom surface of the blade 6. The blade is slidably arranged on the wheel shaft, the shaft hole is arranged on the blade 6 and is matched with the wheel shaft, and the straight key for the axial sliding of the blade 6 is arranged on the shaft hole.

[0050] The working principle is as follows: At high flow rates, the blades tend to slide downwards along the wheel axis. With the help of the bottom cylinder, upper cylinder, and elastic block, the upper cylinder moves downwards with the blades, and the elastic block is pressed slightly into the groove on the outer surface of the bottom cylinder by a certain distance, so that the blade tip clearance meets the design range. At low flow rates, due to the effect of the elastic block (which is under less pressure), the elastic block extends more, and the blades move slightly upwards with the upper cylinder, reducing the blade tip clearance and avoiding surge when the air intake is low. Example 4

[0051] The difference from Embodiment 1 is that, as Figure 17 As shown (for ease of illustration, only the flow amplification device at the lower suction chamber is shown), a flow amplification device is installed in front of the suction chamber 4. The flow amplification device is a blower 20 connected to the suction chamber 4 through a connecting pipe 19. An on / off valve 21 is installed on the connecting pipe, and a flow sensor 22 is installed inside the connecting pipe 19. The flow sensor 22 is electrically connected to the controller 14 (the controller 14 is located outside the blower 20 and this air-suspended centrifugal blower). When the flow rate is not in the surge region (that is, not a small flow rate that will cause the air-suspended centrifugal blower to surge), the controller 14 controls the on / off valve 21 on the connecting pipe to open, and at the same time, the controller controls the high-speed permanent magnet motor of the air-suspended centrifugal blower to run.

[0052] There are at least two blowers, and the power of the two blowers increases sequentially along the air intake direction. Adjacent blowers are connected by a connecting pipe 19, and an on / off valve 21 can also be installed on the connecting pipe.

[0053] The working principle is as follows: A flow amplification device is installed in front of the suction chamber, so that the flow entering the suction chamber leaves the surge zone; and the flow amplification device, through the setting of a blower with gradually increasing power, makes the airflow gradually transition to the non-surge zone of the suspended centrifugal blower, which can also avoid the surge of the flow amplification device (i.e., the blower set in front of the suction chamber) itself as much as possible (or due to this setting, the surge is only sent to the blower in front of the suction chamber, which can avoid the problem of premature wear of the more expensive air suspension centrifugal blower).

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An air-suspended centrifugal blower that avoids large-amplitude airflow oscillations, characterized in that, The device includes a centrifugal blower housing, a high-speed permanent magnet motor housed within the housing, an impeller connected to the output shaft of the high-speed permanent magnet motor within a volute, a suction chamber connected to the middle of the volute, an air outlet connected to an air outlet pipe extending beyond the top surface of the housing, and an air inlet filter installed on the side of the housing facing the air inlet of the suction chamber. The impeller includes blades and a shaft, with shaft holes on the blades adapted to the shaft, and straight keys on the shaft holes for 6-axis sliding of the blades. An adjustment mechanism for adjusting the blade tip clearance is installed on the impeller shaft. The adjustment mechanism includes a bottom cylinder sleeved outside the shaft, fixedly connected to the shaft, with a ring of elastic blocks arranged in a circular array around the rotation axis of the bottom cylinder. Blind hole-shaped grooves are cut out on the outer surface of the bottom cylinder corresponding to the positions of the elastic blocks. An upper cylinder is sleeved outside the bottom cylinder, with the upper end face of the upper cylinder fixedly connected to the bottom surface of the blades.

2. The air-suspended centrifugal blower for avoiding large-amplitude airflow oscillations according to claim 1, characterized in that, The air outlet pipe is connected to an air outlet branch pipe, and one end of the air outlet branch pipe extends beyond the top surface of the housing.

3. The air-suspended centrifugal blower for avoiding large-amplitude airflow oscillations according to claim 2, characterized in that, The housing is made of carbon steel, with sound insulation cotton lining the inner wall and a baked enamel anti-corrosion layer on the surface. Several weight-reducing grooves are provided on the inner wall of the axle hole, arranged in a circular array around the center line of the axle hole.

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