Immersed rotary ceramic membrane aeration device

Abstract

The invention discloses an immersed rotary ceramic membrane aeration device. The immersed rotary ceramic membrane aeration device comprises a base, a waterproof rotary motor, a rotary ceramic membrane component and a rotary joint, an internal air channel of the rotary ceramic membrane comprises an inner ring air collection cavity, a plurality of air flow channels with the same size and structure and an outer ring aeration cavity, the inner ring air collection cavity is communicated with air outlet holes corresponding to the rotary ceramic membrane where the inner ring air collection cavity is located and is communicated with the outer ring aeration cavity through the air flow channels, and different air flow channels distribute air independently. The inner ring gas collection cavity carries out secondary distribution on inlet gas, so that gas distribution is more uniform, the gas subjected to secondary distribution passes through the gas flow channels to be uniformly aerated, and meanwhile, the outer ring aeration cavity at the tail ends of the gas flow channels communicates all the gas flow channels, so that the aeration uniformity in each gas flow channel is further ensured. The whole device can be submerged in water for use, and installation, maintenance and application are all relatively flexible, simple and convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of rotary ceramic membrane application, and in particular relates to an immersed rotary ceramic membrane aeration device. Background Art

[0002] CN111888955A discloses a micro-nano bubble generating device, an air flotation device and a liquid treatment method. The technical solution includes a frame, a micro-nano bubble generating component, a driving mechanism, a gas compressor and an air pipe. The micro-nano bubble generating component includes a hollow shaft with a cavity, a plurality of microporous ceramic diaphragms sleeved on the hollow shaft and a bracket. The micro-nano bubble generating device of the technical solution is developed based on the rotating membrane technology. The microporous ceramic diaphragm used directly induces the generation of nano-scale bubbles without dissolving the gas in water. The generated bubbles have a small diameter and a high uniformity of bubble size.

[0003] CN116675325A discloses a ceramic membrane aeration device, an ozone contact tank suitable for micro-nano aeration, and an aeration method. This technical solution can produce micro-nano bubbles. Compared with the millimeter-level bubbles produced by microporous aeration, O3-MNBs (ozone micro-nano bubbles) have a long residence time in water, a large specific surface area, and a high mass transfer efficiency. More reactive oxygen species (ROS) can be produced, thereby enhancing the oxidative degradation efficiency of ozone on various pollutants. In addition, the aeration method described in this technical solution combines ozone pressure, water inlet flow rate, and ceramic membrane pore size to produce O3-MNBs with an average particle size of less than 50 μm, improve the mass transfer efficiency of ozone in water, strengthen the generation of free radicals, and avoid the use of high-energy consumption equipment such as dissolved air pumps, which can significantly reduce the production cost of O3-MNBs.

[0004] CN214653899U discloses a ceramic membrane micro-nano aeration device. This technical solution increases the contact area between the gas and the sewage in the shell by setting the aeration nozzle into a cylindrical structure and opening multiple groups of air holes on the inner wall of the aeration nozzle, thereby improving the aeration effect of the ceramic membrane micro-nano aeration device.

[0005] CN116675325A and CN214653899U both use ceramic membrane as the aeration generation unit of micro-nano bubbles, and the main principle is to control the particle size of micro-nano bubbles by controlling the size of the membrane pore size and the aeration pressure. However, in the process of bubble generation and separation from the ceramic membrane assembly, when the gas, liquid and solid three-phase medium coexist, there is interfacial tension and interfacial energy on the interface between each two phases, which inevitably causes the bubble to adhere to the ceramic membrane. When a large number of bubbles adhere to the surface of the ceramic membrane, adhesion and reunion will occur between the bubbles and the bubbles, making the bubble particle size larger, and it is difficult to form a large number of micro-nano bubbles with a particle size less than 100 μm. Therefore, the method of static ceramic membrane aeration is used to prepare micro-nano bubbles, and the efficiency is very low, and the dissolved gas effect will be greatly reduced. And CN111888955A uses a rotating ceramic membrane for aeration, and the microbubbles can be separated from the surface of the ceramic membrane in time during the rotation of the membrane, avoiding the situation of bubble reunion and particle size enlargement. However, this technical solution does not have more detailed designs for the structure of the ceramic diaphragm itself, and the core technology of rotating disc membrane aeration lies in the design of the gas flow channel of the diaphragm. Only a scientific and reasonable structural design can maximize the aeration efficiency. In the gas flow channel structure design on the inner side of the ordinary ceramic diaphragm, the flow channel height is uniform. Due to the influence of centrifugal force during the high-speed rotation of this diaphragm, the pressure in the gas flow channel of the diaphragm will gradually increase from the central axis to the outer circle, causing the outer circle of the diaphragm to bubble first, but the inner circle cannot reach the pressure of trans-membrane aeration. The aeration of the entire diaphragm is very uneven, and only the outer circle is partially aerated, so the dissolved gas efficiency is greatly reduced. Summary of the invention

[0006] The present invention aims to overcome the defects of the prior art and provide an immersed rotary ceramic membrane aeration device.

[0007] The technical solution of the present invention is as follows:

[0008] An immersed rotary ceramic membrane aeration device comprises a base, a waterproof rotary motor, a rotary ceramic membrane assembly and a rotary joint;

[0009] A rotating ceramic membrane assembly comprises a hollow shaft and a plurality of rotating ceramic membranes, wherein the hollow shaft has an inner cavity along its length direction, one end of the inner cavity is open and the other end is closed, and the hollow shaft has a plurality of groups of air outlet holes arranged at equal intervals along its length direction, and each air outlet hole is connected to the inner cavity of the hollow shaft; the plurality of rotating ceramic membranes are installed on the hollow shaft in a parallel and sealed manner; an intermediate seal is arranged between adjacent rotating ceramic membranes, and the rotating ceramic membranes at both ends are provided with end seals; in each rotating ceramic membrane, the effective aeration area of ​​its internal air passage accounts for 50-70% of the total area of ​​the rotating ceramic membrane, and comprises an inner ring air collecting cavity, a plurality of air passages of the same size and structure, and an outer ring aeration cavity; the inner cavity of the hollow shaft, the plurality of air outlet holes of the hollow shaft, the inner ring air collecting cavity, the plurality of air passages, and the outer ring aeration cavity are connected in sequence, and the plurality of air passages are distributed in a spiral shape at equal intervals in the rotating ceramic membrane;

[0010] A waterproof rotating motor drives the other end of the hollow shaft;

[0011] The rotary joint has a rotatable air outlet and an air inlet connected to an external air source, wherein the air outlet is sealed and connected to one end of the inner cavity of the hollow shaft;

[0012] The rotating ceramic membrane assembly, the waterproof rotating motor and the rotating joint are all installed on the base;.

[0013] In a preferred embodiment of the present invention, among the plurality of air flow passages, one end of each air flow passage connected to the inner ring air collecting chamber is smaller than the other end connected to the outer ring aeration chamber.

[0014] In a preferred embodiment of the present invention, in the internal air channel, the transmembrane pressure gradually increases from the hollow shaft to the edge of the rotating ceramic membrane.

[0015] Further preferably, the overall thickness of the rotating ceramic membrane remains unchanged, and the height of the internal air channel gradually decreases from the hollow shaft to the edge of the rotating ceramic membrane.

[0016] More preferably, the height of the internal air channel gradually decreases from 30% to 60% of the overall thickness to 10% to 30%.

[0017] Further preferably, the overall thickness of the rotating ceramic membrane gradually increases from the hollow shaft to the edge of the rotating ceramic membrane, and the overall height of the internal airway remains unchanged.

[0018] More preferably, the overall thickness of the rotating ceramic membrane gradually increases from 1.5 to 3 times the height of the internal airway to 2 to 5 times.

[0019] Further preferably, the overall thickness of the rotating ceramic membrane remains unchanged, the overall height of the internal air channel remains unchanged, and the pore size of the membrane layer of the rotating ceramic membrane gradually decreases from the hollow shaft to the edge of the rotating ceramic membrane.

[0020] In a preferred embodiment of the present invention, the cross section of the hollow shaft is a square with chamfered top corners, the intermediate seal has a mounting center hole adapted to the cross section of the hollow shaft, the rotating ceramic membrane has a central through hole, the side wall of the central through hole has a plurality of air inlet holes connected to the inner ring gas collecting cavity, the outer periphery of the mounting center hole is provided with two sealing rings corresponding to the adjacent two rotating ceramic membranes, and a plurality of positioning columns are arranged at equal intervals along the periphery of the mounting center hole between the sealing ring and the mounting center hole, the intermediate seal and the rotating ceramic membrane are both sleeved on the hollow shaft, the plurality of positioning columns are positioned to fit the central through hole of the rotating ceramic membrane to position the rotating ceramic membrane, the intermediate seal realizes end face sealing with the adjacent two rotating ceramic membranes through the sealing ring, the periphery of the mounting center hole of the intermediate seal and the edge of the cross section of the hollow shaft have a gap of 10-50 μm, the gap, the sealing ring, the intermediate seal and the rotating ceramic membrane corresponding to the sealing ring form an air chamber, and the air chamber connects the air outlet of the hollow shaft and the plurality of air inlet holes on the side wall of the central through hole of the rotating ceramic membrane. .

[0021] Further preferably, the air inlet direction and the air outlet direction of the rotary joint are perpendicular to each other.

[0022] The beneficial effects of the present invention are:

[0023] 1. The internal air passage of the rotating ceramic membrane in the present invention includes an inner ring air collecting chamber, a plurality of air passages of the same size and structure, and an outer ring aeration chamber. The inner ring air collecting chamber is connected to the air outlet holes corresponding to the rotating ceramic membrane where it is located, and is connected to the outer ring aeration chamber through a plurality of air passages. Different air passages distribute air independently. The inner ring air collecting chamber distributes the incoming air for a second time to make the air distribution more uniform. The gas after the second distribution is evenly aerated through the air passage. At the same time, the outer ring aeration chamber at the end of the air passage connects all the air passages, further ensuring the uniformity of aeration in each air passage.

[0024] 2. The effective aeration area of ​​the internal air channel of the rotating ceramic membrane in the present invention accounts for 50-70% of the total area of ​​the rotating ceramic membrane. Several air channels are distributed in an equidistant spiral shape in the rotating ceramic membrane. The end of each air channel connected to the inner ring air collecting chamber is smaller than the other end connected to the outer ring aeration chamber. This can maximize the effective area of ​​the air channel and keep the supporting walls of the air channels distributed inside the rotating ceramic membrane with sufficient width to ensure the overall strength of the rotating ceramic membrane. On the one hand, it is beneficial to the flow and diffusion of gas during the rotation of the rotating ceramic membrane, reduces the resistance of the side wall of the air channel to the gas, and saves more energy. On the other hand, it optimizes the effective aeration area and strength of the rotating ceramic membrane to the greatest extent.

[0025] 3. In the internal air channel of the rotating ceramic membrane of the present invention, the trans-membrane pressure gradually increases from the hollow shaft to the edge of the rotating ceramic membrane. Due to the effect of centrifugal force during rotation, the closer to the outer edge of the rotating ceramic membrane, the greater the centrifugal force, the greater the pressure in the internal air channel, and the easier it is for the gas to escape. Therefore, this design can make the rotating ceramic membrane bubble evenly.

[0026] 4. The present invention as a whole can be submerged in water for use, and installation, maintenance and application are relatively flexible and simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the submerged rotary ceramic membrane aeration device of the present invention.

[0028] Figure 2 It is a schematic diagram of the three-dimensional structure of the intermediate sealing member in the present invention.

[0029] Figure 3 It is a schematic diagram of the cooperation between the intermediate seal and the rotating ceramic membrane in the present invention.

[0030] Figure 4 It is a schematic diagram of the structure of the internal air passage of the rotating ceramic membrane in the present invention.

[0031] Figure 5 It is a cross-sectional view of a type A rotating ceramic membrane of the rotating ceramic membrane in the present invention.

[0032] Figure 6 It is a cross-sectional view of a B-type rotating ceramic membrane of the rotating ceramic membrane in the present invention.

[0033] Figure 7 It is a cross-sectional view of a C-type rotating ceramic membrane of the rotating ceramic membrane in the present invention.

[0034] Figure 8 It is a schematic diagram of the three-dimensional structure of the void shaft in the present invention.

[0035] Fig. 9 It is a schematic diagram of the three-dimensional structure of the rotary joint in the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further illustrated and described below through specific implementation modes in combination with the accompanying drawings.

[0037] Example 1

[0038] like Figure 1 As shown, an immersed rotary ceramic membrane aeration device comprises a base 1, a waterproof rotary motor 2, a rotary ceramic membrane assembly 3 and a rotary joint 4;

[0039] like Figure 1 and Figure 8 As shown, the rotating ceramic membrane assembly 3 includes a hollow shaft 31 and a plurality of rotating ceramic membranes 32. The hollow shaft 31 has an inner cavity 310 along its length direction. One end of the inner cavity 310 is open and the other end is closed. The hollow shaft 31 has a plurality of air outlet holes 311 arranged at equal intervals along its length direction. Each air outlet hole 311 is connected to the inner cavity 310 of the hollow shaft 31. The plurality of rotating ceramic membranes 32 are sealed and installed on the hollow shaft 31 in parallel.

[0040] The cross section of the hollow shaft 31 is a square with chamfered top corners; an intermediate seal 33 is provided between adjacent rotating ceramic membranes 32, and the rotating ceramic membranes 32 at both ends are provided with end seals 34; Figure 2 , Figure 3 and Figure 4 As shown, the intermediate seal 33 has a mounting center hole 330 adapted to the cross section of the hollow shaft 31, the rotating ceramic membrane 32 has a central through hole 321, and the side wall of the central through hole 321 has a plurality of air inlet holes 3210. The outer periphery of the mounting center hole 330 is provided with two sealing rings 331 corresponding to the two adjacent rotating ceramic membranes 32. Between the sealing ring 331 and the mounting center hole 330, there are a plurality of positioning columns 332 arranged at equal intervals along the periphery of the mounting center hole 330. The intermediate seal 33 and the rotating ceramic membrane 32 are both mounted on the hollow shaft 31, and the plurality of positioning columns 332 are positioned to adapt to the rotating The central through hole 321 of the ceramic membrane 32 is used to position the rotating ceramic membrane 32. The intermediate seal 33 realizes end face sealing with the two adjacent rotating ceramic membranes 32 through the sealing ring 331. The periphery of the installation center hole 330 of the intermediate seal 33 and the edge of the cross section of the hollow shaft 31 have a gap of 10-50μm. The gap, the sealing ring 331, the intermediate seal 33 and the rotating ceramic membrane 32 corresponding to the sealing ring 331 form an air chamber 333. The air chamber 333 connects the air outlet 311 of the hollow shaft 31 and the several air inlet holes 3210 on the side wall of the central through hole 321 of the rotating ceramic membrane 32.

[0041] like Figure 4As shown, in each rotating ceramic membrane 32, the effective aeration area of ​​the internal air channel 320 accounts for 50-70% of the total area of ​​the rotating ceramic membrane 32, including an inner ring gas collecting cavity 3201 that passes through the above-mentioned plurality of air inlet holes 3210, a plurality of air channels 3202 of the same size and structure, and an outer ring aeration cavity 3203. The inner ring gas collecting cavity 3201 is connected to the above-mentioned air outlet holes 311 corresponding to the rotating ceramic membrane 32 where it is located, and is connected to the outer ring aeration cavity 3203 through a plurality of air channels 3202. Different air channels 3202 are independently distributed. The inner ring gas collecting cavity 3201 performs secondary distribution on the intake air to make the air distribution more uniform. The secondary distributed gas is evenly aerated through the air channels 3202. At the same time, the outer ring aeration cavity 3203 at the end of the air channel 3202 connects all the air channels 3202, further ensuring the uniformity of aeration in each air channel 3202.

[0042] Several air channels 3202 are distributed in a spiral shape at equal intervals in the rotating ceramic membrane 32; one end of each air channel 3202 connected to the inner ring gas collecting cavity 3201 is smaller than the other end connected to the outer ring aeration cavity 3203. In this way, the effective area of ​​the air channel can be maximized, while the supporting wall of the air channel 3202 distributed inside the rotating ceramic membrane 32 is kept wide enough to ensure the overall strength of the rotating ceramic membrane 32; on the one hand, it is conducive to the flow and diffusion of the gas during the rotation of the rotating ceramic membrane 32, reducing the resistance of the side wall of the air channel 3202 to the gas, saving more energy consumption, and on the other hand, optimizing the effective aeration area and strength of the rotating ceramic membrane 32 to the greatest extent.

[0043] In this embodiment, preferably, the width of the inner ring air collecting cavity 3201 is 5-30 mm, the number of air flow channels 3202 is 10-50, the width of the outer ring aeration cavity 3203 is 5-30 mm, the width of the air flow channel 3202 close to one end of the outer ring aeration cavity 3203 = the inner circumference length of the outer ring aeration cavity 3203 / the number of air flow channels 3202-the side wall thickness of the air flow channel 3202 close to one end of the outer ring aeration cavity 3203, and the width of the air flow channel 3202 close to one end of the outer ring aeration cavity 3203 is 5-30 mm, and its design requirement should not be too large, otherwise the rotating ceramic membrane 32 is prone to collapse during the sintering process and is prone to explosion during the operation process.

[0044] Preferably, in the internal air channel 320, the transmembrane pressure gradually increases from the hollow shaft 31 to the edge of the rotating ceramic membrane 32. Due to the centrifugal force during the rotation process, the closer to the outer edge of the rotating ceramic membrane 32, the greater the centrifugal force, the greater the pressure in the internal air channel 320, and the easier it is for the gas to escape, so this design can make the rotating ceramic membrane 32 evenly bubble. The specific options are as follows:

[0045] A type rotating ceramic membrane 32: Figure 5As shown, the overall thickness of the rotating ceramic membrane 32 remains unchanged (4-10 mm), and the height of the internal air channel 320 gradually decreases from the hollow shaft 31 to the edge of the rotating ceramic membrane 32. The height of the internal air channel 320 gradually decreases from 30% to 60% of the overall thickness to 10% to 30%.

[0046] B type rotating ceramic membrane 32: Figure 6 As shown, the overall thickness of the rotating ceramic membrane 32 gradually increases from the hollow shaft 31 to the edge of the rotating ceramic membrane 32, and the overall height of the internal air channel 320 remains unchanged (1.2-6 mm). The overall thickness of the rotating ceramic membrane 32 gradually increases from 1.5 to 3 times the height of the internal air channel 320 to 2 to 5 times.

[0047] C-type rotating ceramic membrane 32: Figure 7 As shown, the overall thickness of the rotating ceramic membrane 32 remains unchanged, the overall height of the internal air channel 320 remains unchanged, and the pore size of the membrane layer of the rotating ceramic membrane 32 gradually decreases from the hollow shaft 31 to the edge of the rotating ceramic membrane 32 .

[0048] According to the mechanical formula:

[0049] P b =P g +P c -P tm

[0050] Where: P b Indicates the aeration pressure,

[0051] P g Indicates the gas supply pressure, which is provided by the external gas supply system;

[0052] P c It represents the centrifugal force, which is the force generated by the gas in the flow channel during the rotation of the diaphragm;

[0053] P tm Indicates the transmembrane pressure, which is the resistance of the ceramic membrane layer to the gas.

[0054] When the present invention starts to run, P g Constant, when the rotating ceramic membrane 32 rotates, as P c The generation of P in different radial distribution areas on the rotating ceramic membrane 32 c It gradually increases from inside to outside, but the P of the above three types of rotating ceramic membranes 32 tm It also gradually increases from the inside to the outside, and P tm The increasing distribution trend and P c The increasing distribution trend is consistent, so in P g Under the condition of no change, the P of different radial distribution areas of the rotating ceramic membrane 32b The rotating ceramic membrane 32 has a large effective bubbling area, the bubble size is evenly controlled, and the total amount of micro-nano bubbles generated is large, which is more than 5 times the number of conventional membranes, and the gas dissolution efficiency is more than 1 times higher than that of conventional membranes.

[0055] The waterproof rotating motor 2 drives the other end of the hollow shaft 31;

[0056] like Fig. 9 As shown, the rotary joint 4 has an air outlet 41 and an air inlet 42 connected to an external air source, and the air outlet 41 is sealed and connected to one end of the inner cavity 310 of the hollow shaft 31; the air inlet direction and the air outlet direction of the rotary joint 4 are perpendicular to each other.

[0057] The rotating ceramic membrane 32 component 3, the waterproof rotating motor 2 and the rotating joint 4 are all installed on the base 1, and the whole can be submerged in water for use. The installation, maintenance and application are relatively flexible and simple. It has a wide range of applications and does not require the configuration of dissolved air tanks, reflux pumps, releasers, etc. It has a simple structure, occupies a small area, and the equipment is more flexible to use and easier to promote. It has low aeration pressure (1-2bar), low installed power, and extremely low energy consumption compared with traditional dissolved air technology. The size of the bubble particle size can be adjusted and controlled by adjusting the operating parameters, which can meet the needs of micro-nano bubbles with different particle sizes in different fields.

[0058] Example 2

[0059] This embodiment uses the submerged rotating ceramic membrane 32 aeration device of Example 1 for operation, wherein the structure of the rotating ceramic membrane 32 is a B-type rotating ceramic membrane 32, and the external gas source is air (the external gas source can be O2, O3, air, H2, CO2, N2 and other gases). The purpose of aeration is to increase the dissolved oxygen and produce a higher concentration of micro-nano bubbles to improve the dissolved gas efficiency.

[0060] Put the rotating ceramic membrane 32 into the pool as a whole, connect the air inlet of the rotating joint 4 to the compressed air supply pipe, and adjust the air supply pressure to 1-2.5 bar; turn on the power of the waterproof rotating motor 2, and adjust the speed to 200-900rpm. The compressed air enters the hollow shaft 31 through the rotating joint 4, and enters the internal air channel 320 of the rotating ceramic membrane 32 from the air outlet 311 of the hollow shaft 31, and is evenly distributed to all air channels 3202. When the air supply pressure exceeds the trans-membrane pressure, the gas is evenly released from the membrane surface into the liquid through the ceramic membrane layer. After the waterproof rotating motor 2 is started, it drives the hollow shaft 31 to rotate, and the hollow shaft 31 then drives the rotating ceramic membrane 32 installed thereon to rotate. When the micro-nano bubbles on the surface of the rotating ceramic membrane 32 are well developed, they are quickly washed away by the fluid shear force on the surface of the rotating ceramic membrane 32, so that the formation of micro-nano bubbles with higher density and more concentrated particle size range can be achieved.

[0061] In the laser particle size analyzer, the shading ratio refers to the degree to which particles block light in the laser light path. The shading ratio can characterize the sample concentration to a certain extent. In an ideal, uniformly dispersed sample system, and under a certain particle size range and optical conditions, the shading ratio and sample concentration are approximately linearly related. The following table is a comparison of the bubble particle size detection and DO improvement efficiency of the traditional diaphragm and the B-type rotating ceramic membrane 32:

[0062]

[0063] In traditional membrane aeration, gas mainly overflows from the outer edge of the membrane, the bubble particle size is large, the total air supply is 0.75LPM, the shading ratio is only 1.7%, and the aeration time for dissolved oxygen from 1mg / L to 7.5mg / L takes 12min, and the overall dissolved gas efficiency is low. With the B-type rotating ceramic membrane 32 aeration, the membrane surface is evenly bubbled. Under the same speed, the air supply only needs 0.45LPM, and the DO can be increased from 1mg / L to 7.5mg / L after 5min of aeration. The gas consumption of the B-type rotating ceramic membrane 32 is only 1 / 4 of the traditional membrane aeration volume. The shading ratio can reach 12%, the water sample appears milky white, and the amount of micro-nano bubbles is significantly increased.

[0064] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. An immersed rotary ceramic membrane aeration device, characterized in that: It includes a base, a waterproof rotating motor, a rotating ceramic membrane component and a rotating joint; A rotating ceramic membrane assembly comprises a hollow shaft and a plurality of rotating ceramic membranes, wherein the hollow shaft has an inner cavity along its length direction, one end of the inner cavity is open and the other end is closed, and the hollow shaft has a plurality of air outlets arranged at equal intervals along its length direction, and each air outlet is connected to the inner cavity of the hollow shaft; the plurality of rotating ceramic membranes are installed on the hollow shaft in a parallel and sealed manner; an intermediate seal is arranged between adjacent rotating ceramic membranes, and the rotating ceramic membranes at both ends are provided with end seals; in each rotating ceramic membrane, the effective aeration area of ​​its internal air passage accounts for 50-70% of the total area of ​​the rotating ceramic membrane, and comprises an inner ring air collecting cavity, a plurality of air passages of the same size and structure, and an outer ring aeration cavity; the inner cavity of the hollow shaft, the plurality of air outlets of the hollow shaft, the inner ring air collecting cavity, the plurality of air passages, and the outer ring aeration cavity are connected in sequence, and the plurality of air passages are distributed in a spiral shape at equal intervals in the rotating ceramic membrane; A waterproof rotating motor drives the other end of the hollow shaft; The rotary joint has a rotatable air outlet and an air inlet connected to an external air source, wherein the air outlet is sealed and connected to one end of the inner cavity of the hollow shaft; The rotating ceramic membrane assembly, the waterproof rotating motor and the rotating joint are all installed on the base;.

2. The submerged rotary ceramic membrane aeration device according to claim 1, characterized in that: Among the plurality of air flow passages, one end of each air flow passage connected to the inner ring air collecting cavity is smaller than the other end connected to the outer ring aeration cavity.

3. The submerged rotary ceramic membrane aeration device according to claim 1, characterized in that: In the internal air channel, the transmembrane pressure gradually increases from the hollow shaft to the edge of the rotating ceramic membrane.

4. The submerged rotary ceramic membrane aeration device according to claim 3, characterized in that: The overall thickness of the rotating ceramic membrane remains unchanged, and the height of the internal air channel gradually decreases from the hollow shaft to the edge of the rotating ceramic membrane.

5. The submerged rotary ceramic membrane aeration device according to claim 4, characterized in that: The height of the internal air channel gradually decreases from 30% to 60% of the overall thickness to 10% to 30%.

6. The submerged rotary ceramic membrane aeration device according to claim 3, characterized in that: The overall thickness of the rotating ceramic membrane gradually increases from the hollow shaft to the edge of the rotating ceramic membrane, and the overall height of the internal air channel remains unchanged.

7. The submerged rotary ceramic membrane aeration device according to claim 6, characterized in that: The overall thickness of the rotating ceramic membrane gradually increases from 1.5 to 3 times the height of the internal air channel to 2 to 5 times.

8. The submerged rotary ceramic membrane aeration device according to claim 3, characterized in that: The overall thickness of the rotating ceramic membrane remains unchanged, the overall height of the internal air channel remains unchanged, and the pore size of the membrane layer of the rotating ceramic membrane gradually decreases from the hollow shaft to the edge of the rotating ceramic membrane.

9. The submerged rotary ceramic membrane aeration device according to any one of claims 1 to 8, characterized in that: The cross section of the hollow shaft is a square with chamfered top corners, the intermediate seal has an installation center hole that matches the cross section of the hollow shaft, the rotating ceramic membrane has a central through hole, the side wall of the central through hole has a plurality of air inlet holes connected to the inner ring air collecting cavity, the outer periphery of the installation center hole is provided with two sealing rings corresponding to the two adjacent rotating ceramic membranes, a plurality of positioning columns are arranged at equal intervals along the periphery of the installation center hole between the sealing ring and the installation center hole, the intermediate seal and the rotating ceramic membrane are both mounted on the hollow shaft, a plurality of positioning columns are positioned to match the central through hole of the rotating ceramic membrane to position the rotating ceramic membrane, the intermediate seal realizes end face sealing with the two adjacent rotating ceramic membranes through the sealing ring, the periphery of the installation center hole of the intermediate seal and the edge of the cross section of the hollow shaft have a gap of 10-50μm, the gap, the sealing ring, the intermediate seal and the rotating ceramic membrane corresponding to the sealing ring form an air chamber, the air chamber connects the air outlet of the hollow shaft and the plurality of air inlet holes on the side wall of the central through hole of the rotating ceramic membrane.

10. The submerged rotary ceramic membrane aeration device according to claim 9, characterized in that: The air inlet direction and the air outlet direction of the rotary joint are perpendicular to each other.

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