A dynamic aeration and scum skimming flotation machine

Abstract

The present application relates to air floatation sewage treatment equipment technical field, provide a kind of dynamic aeration and scum scraping air floatation machine, including air floatation pool, scrape residue device and dissolved air release pipeline, the moving direction of scum scraping plate is configured to be opposite with water body flow direction;Dissolved air release pipeline includes main pipe, several branch pipes, several dissolved air release heads are arranged on each branch pipe, dynamic release valve is arranged at the connecting node of main pipe and each branch pipe;Scum scraping plate below is connected with guide column, guide column below is fixedly connected with trigger block;Trigger block is configured as: when scum scraping plate moves to preset position, the trigger block below is triggered simultaneously along the length direction of air floatation pool Three dynamic release valves arranged;The valve opening of three dynamic release valves triggered simultaneously is sequentially increased along the moving direction of scum scraping plate, in the same air floatation pool, aeration and scum scraping are carried out simultaneously, so that water flow sequentially experiences " high aeration generates scum, middle aeration lifts scum, zero aeration enriches scum " complete process.

Description

Technical Field

[0001] This invention relates to the technical field of air flotation wastewater treatment equipment, specifically to an air flotation machine with dynamic aeration and scum removal. Background Technology

[0002] Aeration and sludge scraping are common steps in dissolved air flotation (DAF) treatment of wastewater. In traditional DAF processes, such as the "composite impeller-type DAF machine" disclosed in Chinese utility model patent application number CN99243522.6, aeration and sludge scraping are usually separated into adjacent tanks. This is because the aeration process relies on high-intensity dissolved air release to create a turbulent field, prompting microbubbles to fully collide and adhere with suspended pollutants (such as flocs), generating a sludge layer. This process requires sufficient fluid disturbance intensity to improve bubble-pollutant contact efficiency, while the sludge scraping process requires a stable still water environment to prevent turbulent water flow from causing the sludge layer to break, swirl, or diffuse, otherwise the scraping efficiency will be significantly reduced. This leads to the need for existing DAF tanks to have a multi-tank series structure, which increases infrastructure costs. In addition, during the transfer of pollutants from the aeration tank to the sludge scraping tank, due to the extended hydraulic retention time, some sludge re-settles due to bubble collapse; to maintain sludge stability, excessive dissolved air is often required, resulting in energy waste. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides a dynamic aeration and scum removal flotation machine, which overcomes the deficiencies of existing technologies, has a reasonable design and compact structure, and solves the problem that existing flotation machines cannot perform aeration and scum removal in the same flotation tank.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention proposes a dynamic aeration and scum removal flotation machine, comprising a flotation tank, a scum scraping device installed at the top of the flotation tank, and a dissolved air release pipeline. The scum scraping device includes a drive belt driven by a motor and scum scraping plates fixed at equal intervals on the drive belt. The motor drives the drive belt to rotate the scum scraping plates in a circular motion above the flotation tank to scrape off scum from the surface of the water in the flotation tank.

[0008] In the flotation tank, the scraper blades in contact with the water surface are configured to move in the opposite direction to the water flow direction.

[0009] The dissolved gas release pipeline includes a main pipe, several branch pipes connected at equal intervals to the side of the main pipe, several dissolved gas release heads set on each of the branch pipes, and dynamic release valves set at the connection nodes between the main pipe and each branch pipe.

[0010] A guide post is connected below the slag scraper, and a trigger block is fixedly connected below the guide post. The trigger block is configured such that when the slag scraper moves to a preset position, the trigger block below it synchronously triggers three dynamic release valves arranged along the length of the flotation tank. The valve openings of the three synchronously triggered dynamic release valves increase sequentially along the moving direction of the slag scraper.

[0011] Preferably, the trigger block is an upper wedge block, and the lower surface of the upper wedge block is a wedge-shaped inclined surface that gradually rises along the moving direction of the scraper.

[0012] The dynamic release valve includes a connecting pipe, a valve pipe connected above the connecting pipe, a valve stem slidably disposed within the valve pipe along the axial direction, a lower wedge block fixed to the top of the valve stem, a fixing plate fixed to the upper outer side of the valve pipe, a guide rod fixed to the bottom of the lower wedge block, a limiting plate fixed to the bottom end of the guide rod, and a compression spring sleeved on the guide rod; wherein, the upper surface of the lower wedge block is configured to match and fit with the wedge-shaped inclined surface of the upper wedge block, the surface of the fixing plate is provided with a guide hole, the guide rod passes through the guide hole and slides in cooperation with the guide hole, and the two ends of the compression spring abut against the upper surface of the fixing plate and the lower surface of the lower wedge block, respectively;

[0013] The valve stem adjusts the insertion depth of its lower end in the connecting pipe by axial displacement, thereby controlling the flow cross-sectional area of ​​the dissolved air water.

[0014] Preferably, the bottom of the valve stem is conical, and a valve seat matching the conical bottom is provided inside the connecting pipe; when the valve stem moves down, the cross-sectional area of ​​the annular gap between the conical bottom and the valve seat decreases with the insertion depth.

[0015] Preferably, the valve stem has an annular groove on its outer periphery, and a piston ring for sealing is embedded in the annular groove.

[0016] Preferably, the trigger block includes a horizontal plate and three spaced photoelectric emitters fixed to the bottom surface of the horizontal plate;

[0017] The dynamic release valve is an electromagnetic proportional valve, and the electromagnetic proportional valve is equipped with a photoelectric receiver corresponding to the photoelectric transmitter.

[0018] The control terminals of the photoelectric transmitter, photoelectric receiver, and electromagnetic proportional valve are all connected to an external controller.

[0019] When the photoelectric receiver receives a signal from the corresponding photoelectric transmitter, the controller adjusts the opening of the corresponding electromagnetic proportional valve according to a preset gradient value.

[0020] Preferably, the scraping surface of the scraper plate is gradually inclined upward relative to the horizontal plane along its moving direction; the lower edge of the scraper plate is within the vertical projection range of the edge of the trigger block below it.

[0021] Preferably, one side of the flotation tank is separated by a sludge collection tank by a partition. The upper edge of the partition is lower than the top of the side wall of the flotation tank. The sewage inlet pipe extends through the partition into the flotation tank, and its outlet faces the side of the flotation tank where the sludge scraping device is located.

[0022] (III) Beneficial Effects

[0023] This invention provides a dynamic aeration and scum removal flotation machine. It has the following beneficial effects:

[0024] This invention simultaneously triggers three-stage gradient aeration zones distributed along the scraping path during the movement of the scraper plate. In the first-stage aeration zone, the PA valve has the largest opening, creating strong turbulence and dense bubble flow to ensure efficient microbubble capture of pollutants. In the second-stage aeration zone, the PB valve opening decreases, and the bubble volume is moderately reduced, forming a stable upward flow to lift the scum layer and avoid turbulence disruption. In the third-stage aeration zone, the PC valve opening is the smallest, maintaining a stable liquid surface flow field and creating a still water environment for scraping. Within the same flotation tank, aeration and scraping are performed simultaneously, allowing the water flow to sequentially undergo a complete process of "high aeration to generate scum, medium aeration to lift scum, and zero aeration to enrich scum," reducing the overall volume of the flotation tank. Real-time linkage between aeration and scraping ensures a fast response, avoiding the problem of scum settling during traditional aeration followed by scraping, thus improving scum removal efficiency. Furthermore, the gradient zoning within a single flotation tank reduces the overall device volume, and the use of triggered gradient aeration reduces dissolved air requirements and energy consumption. Attached Figure Description

[0025] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0026] Figure 2 for Figure 1 A magnified view of part A in the middle;

[0027] Figure 3 for Figure 1 Side view;

[0028] Figure 4 for Figure 3 A magnified view of part B in the middle section;

[0029] Figure 5 A schematic diagram of one embodiment of a dynamic release valve;

[0030] Figure 6 This is a schematic diagram illustrating the cooperation between the trigger block and the dynamic release valve in another implementation method;

[0031] Figure 7 This is a schematic diagram of the connection between the slag scraper and the upper wedge block.

[0032] In the diagram: 1. Flotation tank; 2. Sludge scraping device; 21. Motor; 22. Transmission belt; 23. Sludge scraper; 24. Guide column; 25. Trigger block; 25a. Upper wedge block; 25b1. Horizontal plate; 25b2. Photoelectric transmitter; 3. Dissolved gas release pipeline; 31. Main pipe; 32. Branch pipe; 33. Dissolved gas release head; 34. Dynamic release valve; 34a1. Connecting pipe; 34a2. Valve pipe; 34a3. Valve stem; 34a31. Annular groove; 34a32. Piston ring; 34a4. Lower wedge block; 34a5. Fixing plate; 34a51. Guide hole; 34a6. Guide rod; 34a7. Limiting plate; 34a8. Compression spring; 34a9. Valve seat; 34b1. Electromagnetic proportional valve; 34b2. Photoelectric receiver; 4. Baffle plate; 5. Sludge collection tank. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] See attached document Figures 1-7 The system includes an air flotation tank 1, a scum scraping device 2 installed at the top of the air flotation tank 1, and a dissolved air release pipeline 3. The scum scraping device 2 includes a transmission belt 22 driven by a motor 21 and scum scraping plates 23 fixed at equal intervals on the transmission belt 22. The motor 21 drives the transmission belt 22 to drive the scum scraping plates 23 to rotate in a circular motion above the air flotation tank 1 to scrape off the scum on the surface of the water in the air flotation tank 1. The dissolved air release pipeline 3 releases microbubbles in the air flotation tank 1 to fully collide and adhere with suspended pollutants (flocculents) to form scum.

[0035] In this invention, in the flotation tank 1, the scum scraper 23 in contact with the water surface is configured to move in the opposite direction to the water flow direction, that is, the scum scraper 23 scrapes the scum in the opposite direction to the water flow direction, and the moving speed of the scum scraper 23 is 0.1-0.3m / s; the scum scraper 23 moves against the water flow to form a "compression effect", and the scum is compressed and thickened under the action of the scraper thrust and the reverse resistance of the water flow, which is conducive to the enrichment of scum.

[0036] Preferably, a sludge collection tank 5 is separated from the flotation tank 1 by a baffle 4 on one side. The upper edge of the baffle 4 is lower than the top of the side wall of the flotation tank 1 to form an overflow weir structure near the top of the tank wall. The sewage inlet pipe extends through the baffle 4 into the flotation tank 1, and its outlet faces the side of the flotation tank 1 where the sludge scraper 2 is located. When the scraper 23 pushes the thickened sludge against the flow of water along the length of the tank to the baffle 4, the sludge can easily overturn the baffle 4 under the thrust and overflow into the sludge collection tank 5. At the same time, the sewage inlet pipe is configured in the opposite direction to the scraper direction, so that the sewage with the highest concentration of suspended impurities that just enters the flotation tank 1 can be quickly contacted and treated by the scraper 23 closest to the sludge collection tank 5. This greatly shortens the residence and diffusion time of pollutants in the tank, avoids contaminating the treated area or increasing the subsequent treatment load, and effectively improves the system's tolerance to fluctuations in influent load and overall treatment efficiency.

[0037] The dissolved gas release pipeline 3 includes a main pipe 31, several branch pipes 32 connected at equal intervals to the side of the main pipe 31, several dissolved gas release heads 33 set on each branch pipe 32, and dynamic release valves 34 set at the connection nodes between the main pipe 31 and each branch pipe 32. Preferably, the dissolved gas release heads 33 are staggered on the branch pipes 32, and the distance between adjacent dissolved gas release heads 33 is 2-3 times the diameter of the dissolved gas release head 33, so as to form a densely distributed aeration area in the flotation tank 1.

[0038] A guide post 24 is connected below the scraper plate 23, and a trigger block 25 is fixedly connected below the guide post 24. The trigger block 25 is configured such that when the scraper plate 23 moves to a preset position, the trigger block 25 below it synchronously triggers three dynamic release valves 34 arranged along the length of the flotation tank 1. The preset position is the working position where the trigger plate can dynamically release the valves 34 and the scraper plate 23 synchronously scrapes sludge on the water surface.

[0039] The scraping surface of the scraper plate 23 gradually tilts upward relative to the horizontal plane along its moving direction. Preferably, the tilt angle of the scraper plate 23 is 8°-15°, which is conducive to the accumulation of scum. The lower edge of the scraper plate 23 is within the vertical projection range of the edge of the trigger block 25 below it, which ensures that the trigger block 25 below it can always be driven and accurately positioned during the movement of the scraper plate 23, thereby ensuring that the trigger block 25 can accurately reach and trigger the dynamic release valve 34 at the preset position.

[0040] Among them, the valve openings of the three synchronously triggered dynamic release valves 34 increase sequentially along the moving direction of the scraper plate 23. As a result, three gradient bubble density aeration zones are formed below the scraper plate 23 from near to far: the primary aeration zone PA, which is farthest from the front of the scraper plate 23; the tertiary aeration zone PC, which is closest to the front of the scraper plate 23; and the secondary aeration zone PB, which is located between the primary aeration zone PA and the tertiary aeration zone PC. In the primary aeration zone PA, the dynamic release valve 34 has the largest opening, forming a dense bubble flow. The strong turbulence causes a large number of microbubbles to adhere to suspended pollutants, forming scum. In the secondary aeration zone PB, the dynamic release valve 34 has a medium opening, and the aeration volume is smaller than that in the primary aeration zone PA. A suitable amount of bubbles form a stable bubble upflow in this area, avoiding turbulence, maintaining the amount of bubbles on the scum surface, preventing turbulence from damaging the scum layer, reducing scum swirling and settling, and keeping the scum on the water surface. In the tertiary aeration zone PC, which is close to the scraper plate 23, the aeration volume is very small or non-existent, maintaining the stability of the liquid surface flow field, preventing the scum from redispersing due to turbulence, creating a still water environment to ensure stable accumulation of scum, which is easy to scrape off. The area covered by the moving trajectory of the scraper plate 23 undergoes a complete process of "high aeration to generate scum, medium aeration to lift scum, and zero aeration to enrich scum." Aeration and scraping are linked in real time, with a fast response speed, avoiding the problem of scum settling during traditional aeration followed by scraping, thus improving the scum cleaning effect. Simultaneously, this invention uses gradient partitioning within a single flotation tank 1, reducing the overall device volume, and employs triggered gradient aeration, reducing dissolved air demand and energy consumption.

[0041] In addition, during a single scraping stroke of the scraper plate 23 from one side of the flotation tank 1 to the other, the trigger block 25 under the guide column 24 moves synchronously, and three sets of dynamic release valves 34 at different positions are continuously triggered along the way. Each time a set of valves is triggered, a new PA, PB, PC gradient aeration zone is generated directly in front of the current scraper plate 23. The width of the gradient aeration zone is relative to the spacing of the scraper plate 23, which makes the water undergo multiple cycles of treatment. That is, a single scraping stroke completes N "aeration-scraping" sub-cycles (N = number of trigger valve sets). The suspended solids undergo repeated bubble capture, and the removal rate of fine particles (such as emulsified oil and colloids) is significantly improved, realizing dynamic continuous aeration and cyclic cleaning of suspended solids in the water.

[0042] In this invention, multiple sets of dynamic release valve assemblies arranged along the length of the pool (each set contains three dynamic release valves 34 corresponding to zones PA, PB, and PC) can operate independently without interfering with each other. Since the water flow direction is against the movement direction of the scraper plate 23 (i.e., from zone PA to zone PC), the dense bubble flow released from zone PA mainly diffuses and rises backward with the water flow under the action of strong turbulence, and basically does not diffuse backward to the PC zone on other trigger valve assemblies. Above the branch pipe connected to the dynamic release valve 34 triggered by the same trigger plate, there is a physical distance (separated by the PB zone) between the high-intensity PA zone and the low / no-aeration PC zone, which limits the direct lateral diffusion range of bubbles. The PB zone in the middle adopts a medium aeration intensity, and its bubble volume is significantly lower than that of the PA zone. Since the water flow velocity controlled by the sewage treatment flotation process is usually low, the horizontal migration distance of bubbles in the direction of water flow is relatively short compared with the distance of the aeration zone within its group. Most bubbles have already completed the floating and capturing of pollutants in the PA and PB zones, and the amount of bubbles that diffuse into the PC zone of this group is minimal. Therefore, the area covered by the movement trajectory of the scraper plate 23 can all undergo the complete process of "high aeration to generate scum, medium aeration to lift scum, and zero aeration to enrich scum".

[0043] In addition, by controlling the moving speed of the scraper plate 23, the moving speed of the trigger block 25 can be changed synchronously, thereby adjusting the action time (i.e. dissolved gas release time) of each dynamic release valve 34 in the triggered state. This optimizes the dissolved gas consumption while ensuring the aeration and scraping effects, thus achieving the goal of energy saving.

[0044] As one specific embodiment of the present invention. Figure 3 , Figure 4 , Figure 5 , Figure 7 The diagram illustrates a specific combination of trigger block 25 and dynamic release valve 34.

[0045] Among them, the trigger block 25 is an upper wedge block 25a, and the lower surface of the upper wedge block 25a is a wedge-shaped inclined surface that gradually rises along the moving direction of the scraper plate 23;

[0046] The dynamic release valve 34 includes a connecting pipe 34a1, a valve pipe 34a2 connected above the connecting pipe 34a1, a valve stem 34a3 slidably disposed within the valve pipe 34a2 along the axial direction, a lower wedge block 34a4 fixed to the top of the valve stem 34a3, a fixing plate 34a5 fixed to the upper outer side of the valve pipe 34a2, a guide rod 34a6 fixed to the bottom of the lower wedge block 34a4, a limiting plate 34a7 fixed to the bottom of the guide rod 34a6, and a compression spring 34a8 sleeved on the guide rod 34a6; wherein, the upper surface of the lower wedge block 34a4 is configured to match and fit against the wedge-shaped inclined surface of the upper wedge block 25a, and the surface of the fixing plate 34a5 is... A guide hole 34a51 is provided on the surface, and the guide rod 34a6 passes through the guide hole 34a51 and slides in cooperation with the guide hole 34a51 to ensure the vertical movement of the valve stem 34a3 and prevent it from deviating and jamming. The two ends of the compression spring 34a8 abut against the upper surface of the fixed plate 34a5 and the lower surface of the lower wedge block 34a4, respectively. The compression spring 34a8 provides a restoring force so that the valve stem 34a3 can be restored to the highest position so that the valve opening is maximized. The upper wedge block 25a converts the horizontal displacement into vertical pressure, triggering the valve opening adjustment. The lower wedge block 34a4 receives the inclined plane thrust and transmits mechanical energy to the valve stem 34a3 so that the valve stem 34a3 is displaced axially.

[0047] The valve stem 34a3 adjusts the insertion depth of its lower end in the connecting pipe 34a1 by axial displacement in order to control the flow cross-sectional area of ​​dissolved air water.

[0048] In this embodiment, the bottom of the valve stem 34a3 is conical, and the connecting pipe 34a1 is provided with a valve seat 34a9 that matches the bottom of the conical shape; when the valve stem 34a3 moves down, the cross-sectional area of ​​the annular gap between the bottom of the conical shape and the valve seat 34a9 decreases with the insertion depth.

[0049] Preferably, an annular groove 34a31 is provided on the outer periphery of the valve stem 34a3, and a piston ring 34a32 for sealing is embedded in the annular groove 34a31.

[0050] During the horizontal movement of the scraper plate 23, the inclined surface of the upper wedge block 25a presses against the lower wedge block 34a4, causing the valve stem 34a3 to move vertically downward linearly. The deeper the lower end of the valve stem 34a3 is inserted into the connecting pipe 34a1, the smaller the cross-sectional area for dissolved air and water flow, and the less air bubbles are released. Since the lower surface of the upper wedge block 25a is a wedge-shaped inclined surface that gradually rises along the moving direction of the scraper plate 23, the lower wedge block 34a4 that is contacted further forward in the moving direction of the upper wedge block 25a has a smaller downward displacement and a larger cross-sectional area for dissolved air and water flow. The three dynamic release valves 34 that are contacted by the upper wedge block 25a form a three-stage aeration zone PA, PB, and PC in sequence from far to near in the moving direction.

[0051] As another specific embodiment of the present invention. Figure 6Another specific combination of trigger block 25 and dynamic release valve 34 is shown.

[0052] The trigger block 25 includes a horizontal plate 25b1 and three spaced photoelectric emitters 25b2 fixed to the bottom surface of the horizontal plate 25b1.

[0053] The dynamic release valve 34 is an electromagnetic proportional valve 34b1, and the electromagnetic proportional valve 34b1 is equipped with a photoelectric receiver 34b2 corresponding to the photoelectric transmitter 25b2.

[0054] The control terminals of the photoelectric transmitter 25b2, the photoelectric receiver 34b2, and the electromagnetic proportional valve 34b1 are all connected to an external controller.

[0055] When the photoelectric receiver 34b2 receives the signal from the corresponding photoelectric transmitter 25b2, the controller adjusts the opening of the corresponding electromagnetic proportional valve 34b1 according to the preset gradient value.

[0056] In this embodiment, non-contact signals replace mechanical contact. Three photoelectric transmitters 25b2 correspond to three aeration zones: when a photoelectric transmitter 25b2 passes above a solenoid valve, different opening values ​​are preset by the controller to achieve gradient control of PA, PB, and PC. The biggest difference between this photoelectric solution and the mechanical solution is that the opening is programmable, no longer limited by the inclined surface physical structure. The photoelectric head sealing design is more resistant to sludge adhesion than mechanical sliding parts. Furthermore, the controller can modify the opening value at any time to respond to changes in water quality, offering high adjustment flexibility. It provides immediate alarm in case of signal interruption, while mechanical valve jamming is difficult to detect in real time, resulting in high reliability.

[0057] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0058] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dynamic aeration and scum removal flotation machine, comprising a flotation tank (1), a scum scraping device (2) disposed on the top of the flotation tank (1), and a dissolved air release pipeline (3), wherein the scum scraping device (2) comprises a transmission belt (22) driven by a motor (21) and scum scraping plates (23) fixed at equal intervals on the transmission belt (22), wherein the motor (21) drives the transmission belt (22) to drive the scum scraping plates (23) to rotate cyclically above the flotation tank (1) to scrape off scum from the surface of the water in the flotation tank (1), characterized in that: In the flotation tank (1), the scraper (23) in contact with the water surface is configured to move in the opposite direction to the water flow direction. The dissolved gas release pipeline (3) includes a main pipe (31), a number of branch pipes (32) connected at equal intervals to the side of the main pipe (31), a number of dissolved gas release heads (33) provided on each of the branch pipes (32), and a dynamic release valve (34) provided at the connection node between the main pipe (31) and each branch pipe (32). A guide post (24) is connected below the scraper plate (23), and a trigger block (25) is fixedly connected below the guide post (24). The trigger block (25) is configured such that when the scraper plate (23) moves to a preset position, the trigger block (25) below it synchronously triggers three dynamic release valves (34) arranged along the length direction of the flotation tank (1). The valve opening of the three synchronously triggered dynamic release valves (34) increases sequentially along the moving direction of the scraper plate (23).

2. The air flotation machine for dynamic aeration and scum removal as described in claim 1, characterized in that: The trigger block (25) is an upper wedge block (25a), and the lower surface of the upper wedge block (25a) is a wedge-shaped inclined surface that gradually rises along the moving direction of the scraper plate (23); The dynamic release valve (34) includes a connecting pipe (34a1), a valve pipe (34a2) connected above the connecting pipe (34a1), a valve stem (34a3) slidably disposed in the valve pipe (34a2) along the axial direction, a lower wedge block (34a4) fixed to the top of the valve stem (34a3), a fixing plate (34a5) fixed to the upper outer side of the valve pipe (34a2), a guide rod (34a6) fixed to the bottom of the lower wedge block (34a4), a limiting plate (34a7) fixed to the bottom end of the guide rod (34a6), and a sleeved on the valve stem (34a2). A compression spring (34a8) is attached to the guide rod (34a6); wherein the upper surface of the lower wedge block (34a4) is configured to match and fit with the wedge-shaped inclined surface of the upper wedge block (25a), a guide hole (34a51) is provided on the surface of the fixing plate (34a5), the guide rod (34a6) passes through the guide hole (34a51) and slides with the guide hole (34a51), and the two ends of the compression spring (34a8) abut against the upper surface of the fixing plate (34a5) and the lower surface of the lower wedge block (34a4) respectively; The valve stem (34a3) adjusts the insertion depth of its lower end in the connecting pipe (34a1) by axial displacement to control the flow cross-sectional area of ​​dissolved air water.

3. The air flotation machine for dynamic aeration and scum removal as described in claim 2, characterized in that: The bottom of the valve stem (34a3) is conical, and the connecting pipe (34a1) is provided with a valve seat (34a9) that matches the bottom of the conical shape; when the valve stem (34a3) moves down, the cross-sectional area of ​​the annular gap between the bottom of the conical shape and the valve seat (34a9) decreases with the insertion depth.

4. The air flotation machine for dynamic aeration and scum removal as described in claim 2, characterized in that: The valve stem (34a3) has an annular groove (34a31) on its outer periphery, and a piston ring (34a32) for sealing is embedded in the annular groove (34a31).

5. The air flotation machine for dynamic aeration and scum removal as described in claim 1, characterized in that: The trigger block (25) includes a horizontal plate (25b1) and three spaced photoelectric emitters (25b2) fixed to the bottom surface of the horizontal plate (25b1). The dynamic release valve (34) is an electromagnetic proportional valve (34b1), and the electromagnetic proportional valve (34b1) is provided with a photoelectric receiver (34b2) corresponding to the photoelectric transmitter (25b2). The control terminals of the photoelectric transmitter (25b2), photoelectric receiver (34b2), and electromagnetic proportional valve (34b1) are all connected to an external controller; When the photoelectric receiver (34b2) receives the signal from the corresponding photoelectric transmitter (25b2), the controller adjusts the opening of the corresponding electromagnetic proportional valve (34b1) according to a preset gradient value.

6. A flotation machine for dynamic aeration and scum removal as described in any one of claims 1-5, characterized in that: The scraping surface of the scraper (23) gradually tilts upward relative to the horizontal plane along its moving direction; the lower edge of the scraper (23) is within the vertical projection range of the edge of the trigger block (25) below it.

7. The air flotation machine for dynamic aeration and scum removal as described in claim 6, characterized in that: The flotation tank (1) is separated from the sludge collection tank (5) by a partition (4) on one side. The upper edge of the partition (4) is lower than the top height of the side wall of the flotation tank (1). The sewage inlet pipe extends through the partition (4) into the flotation tank (1), and its outlet faces the side of the flotation tank (1) where the sludge scraping device (2) is located.

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