A dissolved air flotation machine
By introducing a cleaning device into the dissolved air flotation machine to automatically clean the surface of the scraper plate, the problem of scum and impurities adhering to the scraper plate and not being able to be cleaned in time is solved, the scum cleaning efficiency is improved and the impurity deposition is reduced, thus achieving high-efficiency operation of the equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANDONG ESSIN ENVIRONMENTAL TECH CO LTD
- Filing Date
- 2025-07-26
- Publication Date
- 2026-06-26
AI Technical Summary
In existing dissolved air flotation machines, the scum and impurities stuck to the scraper cannot be cleaned in time, resulting in low efficiency of scum scraping back and increasing the deposition of impurities in the separation zone.
Various cleaning devices were designed, including cleaning devices A, B, and C. Through the combination of support plates, clamping plates, connecting shafts, nuts, and cleaning plates, and using silicone material or spring structures, the surface of the scraper plate is automatically cleaned, ensuring that the scraper plate remains clean during the circulation process.
This improves the cleaning efficiency of the scraper, avoids secondary deposition of impurities, and ensures the cleanliness of the separation zone and the efficient operation of the equipment.
Smart Images
Figure CN224411481U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of water treatment technology, and in particular to a dissolved air flotation machine. Background Technology
[0002] Dissolved air flotation is a high-efficiency solid-liquid separation device. Its core principle is to inject high-pressure dissolved air water into the water, which instantly releases a large number of micron-sized bubbles. The bubbles adsorb suspended solids, oils, or colloidal substances in the wastewater, forming flocs with a density less than water, which then quickly float to the surface, thereby achieving the separation of pollutants from clean water.
[0003] In the separation zone between pollutants and clean water, a scum scraper is usually used to scrape off the scum at the top of the separation zone. After contacting the scum, the scraper plate usually sticks to the plate surface. As the scraper plate operates in a cyclical manner, the scraper plate at the end of the separation zone, covered with scum, returns to the beginning of the separation zone. This causes the scum on the scraper plate to come into contact with the water flow again, causing the scum to be scraped off again. This reduces the efficiency of the scraper plate in removing scum and inevitably causes impurities in the returned scum to settle, increasing the deposition of impurities in the separation zone. Utility Model Content
[0004] The purpose of this invention is to provide a dissolved air flotation machine that solves the problems in the prior art, such as the inability to clean up the scum and impurities adhering to the scraper plate in a timely manner, the phenomenon of repeated scraping, and the increase of impurity deposition in the separation zone.
[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0006] A dissolved air flotation machine includes a body, a separation zone is provided inside the body, and a slag scraping device is provided above the separation zone. The slag scraping device includes a conveyor chain, a slag scraping motor, a transmission device, slag scraping plates, and a cleaning plate device. The conveyor chain is installed to the body via a shaft and bearing seats. The slag scraping motor is fixed to the top of the body and is driven by the transmission device. Multiple slag scraping plates are installed on the conveyor chain. A cleaning plate device is installed on the body at the tail end of the separation zone.
[0007] Preferably, the cleaning device is a cleaning device A, which includes a support plate A, a clamping plate A, a connecting shaft A, a nut A, and a cleaning plate A. The two support plates A are fixed to the body at the tail end of the separation zone. The clamping plate A has a connecting shaft A fixed at both ends. The two connecting shafts A pass through the two support plates A and are threadedly installed by the nuts A. The cleaning plate A is clamped and fixed below the clamping plate A. The bottom of the cleaning plate A is in contact with the rotating scraper plate.
[0008] Preferably, the cleaning plate A is made of silicone.
[0009] Preferably, the cleaning device is a cleaning device B, which includes a support plate B, a clamping plate B, a connecting shaft B, a nut B, a sliding groove B, and a cleaning plate B. The two support plates B are fixed to the body at the tail end of the separation zone. The clamping plate B is fixed with a connecting shaft B at both ends. The two connecting shafts B pass through the two support plates B and are threaded on by nuts B. The clamping plate B has a sliding groove B inside, and the cleaning plate B is slidably connected to the sliding groove B. The bottom of the cleaning plate B contacts the rotating scraper plate.
[0010] Preferably, a plurality of springs B are provided in the chute B, with the top of the springs B fixed to the top of the chute B and the bottom fixed to the top of the cleaning plate B.
[0011] Preferably, the cleaning device is a cleaning device C, which includes a support plate C, a track groove C, a clamping plate C, a connecting shaft C, and a cleaning plate C. Two support plates C are fixed to the body at the tail end of the separation zone. The support plate C has a track groove C that is inclined towards the upper part of the tail end of the separation zone. The track groove C is a rectangular groove. The clamping plate C has a connecting shaft C fixed at both ends. The connecting shaft C is a square bar and slides along the track groove C on both sides. The cleaning plate C is clamped and fixed below the clamping plate C. The bottom of the cleaning plate C is in contact with the rotating scraper plate.
[0012] Preferably, a top plate C is vertically fixed to the support plate C at the top of the track groove C, and a spring C is installed between the top plate C and the end of the connecting shaft C on the same side.
[0013] Preferably, a flocculation zone, a coagulation aid zone, and an air flotation contact zone are sequentially arranged between the water inlet end of the machine body and the initial section of the separation zone. A sewage discharge zone and a clean water zone are sequentially arranged between the tail end of the separation zone and the water outlet end of the machine body. The upper part of the separation zone is connected to the sewage discharge zone, and the lower part is connected to the clean water zone. An inlet is connected to the outside of the flocculation zone, and an outlet is connected to the outside of the clean water zone.
[0014] Preferably, a dissolved air system is connected to the outside of the air flotation contact area. The dissolved air system includes a dissolved air tank, a microbubble releaser, a return water pipe, and a return water pump. The dissolved air tank is fixed to the outside of the machine body. The microbubble releaser connected to the dissolved air tank is located at the bottom of the air flotation contact area. The dissolved air tank is connected to the clear water area by a return water pipe, and a return water pump is installed on the return water pipe.
[0015] Preferably, a separation zone drain outlet is installed at the bottom of the separation zone, and a drain outlet is installed at the bottom of the drain zone.
[0016] The advantages of this utility model compared with the prior art are as follows:
[0017] The cleaning device cleans the surface of the scraper plate passing through the tail end of the separation zone, scraping off the floating scum and impurities on the scraper plate to the tail end of the separation zone. This makes it easier for the scraper plate to be pushed into the sewage discharge zone after the next passing of the scraper plate. This allows the scraper plate to return to the initial end of the separation zone in a continuous cycle, keeping it clean, increasing the cleaning efficiency of floating scum and impurities, and preventing the return of impurities and the resulting sedimentation and accumulation. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the appearance structure of Embodiment 1 of this utility model;
[0019] Figure 2 This is a top view of Embodiment 1 of this utility model;
[0020] Figure 3 This is a front view of Embodiment 1 of this utility model;
[0021] Figure 4 This is a schematic diagram of the clearing device A in Embodiment 1 of this utility model;
[0022] Figure 5 This is a schematic diagram of the clearing device B in Embodiment 2 of this utility model;
[0023] Figure 6 This is a cross-sectional view of groove B in Embodiment 2 of this utility model;
[0024] Figure 7 This is a schematic diagram of the clearing device C in embodiment 3 of this utility model;
[0025] Figure 8 This is a front view of the clearing device C in embodiment 3 of this utility model;
[0026] Icons: 1. Body; 2. Flocculation Zone; 3. Coagulation Aid Zone; 4. Air Flotation Contact Zone; 41. Dissolved Air Tank; 42. Microbubble Releaser; 43. Return Water Pipe; 44. Return Water Pump; 5. Separation Zone; 51. Separation Zone Drain; 6. Sludge Scraping Device; 61. Conveyor Chain; 62. Sludge Scraping Motor; 63. Transmission Device; 64. Sludge Scraping Blade; 65. Cleaning Plate Device; 651. Cleaning Plate Device A; 6511. Support Plate A; 6512. Clamping Plate A; 6513. Connecting Shaft A; 6514. Nut A; 6515. Cleaning Plate A; 652. Cleaning... Plate device B; 6521, Support plate B; 6522, Clamping plate B; 6523, Connecting shaft B; 6524, Nut B; 6525, Slide groove B; 6526, Cleaning plate B; 6527, Spring B; 653, Cleaning plate device C; 6531, Support plate C; 6532, Track groove C; 6533, Clamping plate C; 6534, Connecting shaft C; 6535, Cleaning plate C; 6536, Top plate C; 6537, Spring C; 7, Sewage discharge area; 71, Sewage discharge outlet of sewage discharge area; 8, Clean water area; 9, Water inlet; 10, Water outlet. Detailed Implementation
[0027] To make the objectives, methods, and advantages of the embodiments of this utility model clearer, the method solutions in the embodiments of this utility model are described clearly and completely. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0028] Example 1
[0029] like Figure 1-4 As shown, a dissolved air flotation machine includes a body 1. An observation corridor 11 is bolted to the outside of the body 1 to facilitate observation and maintenance of the internal areas. A separation zone 5 is provided inside the body 1 for solid-liquid separation of raw water. A scum scraper 6 is installed above the separation zone 5 to scrape off floating scum. A flocculation zone 2, a coagulation aid zone 3, and an air flotation contact zone 4 are sequentially arranged between the water inlet end of the body 1 and the initial section of the separation zone 5. The dissolved air system is connected to the air flotation contact zone 4 to generate microbubbles that cause the flocs to float. A sewage discharge zone 7 and a clean water zone 8 are arranged sequentially between the tail end of the separation zone 5 and the water outlet of the body 1. The upper part of the separation zone 5 is connected to the sewage discharge zone 7 and the lower part is connected to the clean water zone 8. A sewage discharge port 51 is installed at the bottom of the separation zone 5 and the sewage discharge port 71 is installed at the bottom of the sewage discharge zone 7. An inlet 9 is connected to the outside of the flocculation zone 2 and an outlet 10 is connected to the outside of the clean water zone 8.
[0030] Specifically, raw water enters the flocculation zone 2 through inlet 9. Flocculant PAC is added to the flocculation zone 2, and an electric motor drives an agitator to stir the water, destabilizing suspended solids and colloidal particles and forming fine flocs. The water then enters the coagulation aid zone 3, where coagulation aid PAM is added. The electric motor drives an agitator to stir the water, further increasing the floc particle size and strengthening the floc structure, thereby improving its ability to adsorb pollutants and subsequently attach bubbles. After effective flocculation, the wastewater carrying the flocs enters the air flotation contact zone 4. Through the pressurized dissolved air system and depressurized release technology, microbubbles are generated and attach to the flocculated suspended solids, significantly reducing the overall density of the flocs and giving them buoyancy. The flocs and bubbles then enter the separation zone 5. Under low-speed water flow, the flocs and bubbles rise to the water surface together, forming scum, achieving solid-liquid separation. The top scum is scraped into the discharge zone 7 by the scum scraper 6, while the lower layer of clear water flows directly into the clear water zone 8 and is discharged through outlet 10. The sludge settled at the bottom of separation zone 5 and the sludge in discharge zone 7 are discharged separately through discharge outlet 51 and discharge outlet 71, respectively.
[0031] The dissolved air system includes a dissolved air tank 41, a microbubble releaser 42, a return water pipe 43, and a return water pump 44. The dissolved air tank 41 is bolted to the outside of the body 1 and is equipped with an electronic control system for automatic regulation. It is supplied with air by an electrically driven compressor. The microbubble releaser 42, which is connected to the dissolved air tank 41, is located at the bottom of the air flotation contact area 4 and is used to spray dissolved air water microbubbles. The dissolved air tank 41 is connected to the clear water area 8 by a return water pipe 43. An electrically operated return water pump 44 is installed on the return water pipe 43 for circulating water supply to the dissolved air tank 41.
[0032] Specifically, the return water pump 44 injects part of the treated clean water from the clean water zone 8 into the dissolved air tank 41 through the return water pipe 43. The compressor continuously inputs air into the dissolved air tank 41. Under high pressure, the air is forced to dissolve in the water to form saturated dissolved air water. The dissolved air water is transported through a pipeline to the microbubble releaser 42 at the bottom of the air flotation contact zone 4. The microbubble releaser 42 causes the dissolved air water pressure to drop sharply through a pressure reducing device, and the supersaturated air in the water is rapidly released to form a dense cluster of microbubbles with a particle size of 20-50μm, which are evenly distributed in the water. This principle is an existing technical means and will not be elaborated further.
[0033] The slag scraping device 6 includes a conveyor chain 61, a slag scraping motor 62, a transmission device 63, slag scraping plates 64, and a cleaning device 65. The conveyor chain 61 is installed on the machine body 1 via a shaft and bearing seat. The slag scraping motor 62 is electrically powered and bolted to the top of the machine body 1. It is driven by the transmission device 63, which is a sprocket and chain drive. Multiple slag scraping plates 64 are installed on the conveyor chain 61 to scrape the slag from the separation zone 5 to the sewage discharge zone 7. The cleaning device 65 is installed on the machine body 1 at the tail end of the separation zone 5 to clean the slag scraping plates 64.
[0034] Specifically, the scraper motor 62 transmits power to the conveyor chain 61 through the transmission device 63, driving the conveyor chain to circulate along a set trajectory. Multiple scraper plates 64 installed on the conveyor chain 61 move at a uniform speed with the chain. The scraper plates 64 are designed with an inclined structure. When they pass the liquid surface of the separation zone 5, they contact the scum layer and push the scum towards the discharge zone 7. The spacing between the scraper plates 64 is matched with the scum generation rate and the chain speed to ensure continuous scraping and avoid scum accumulation or omission. When the scraper plates 64 rotate to the end of the separation zone 5 and are close to the discharge zone 7, they are cleaned by the cleaning device 65 to achieve automatic cleaning of the scum remaining on the surface of the scraper plates 64. This ensures efficient cyclic operation of the scraper plates 64, improves the cleaning efficiency of scum and impurities, and also avoids the phenomenon of impurities returning to the separation zone 5 and increasing sludge sedimentation and accumulation.
[0035] It is worth mentioning that the motors used for stirring in the flocculation zone 2 and the coagulation aid zone 3, the dissolved air tank 41 and the air compressor supplying air, the slag scraper motor 62 and the return water pump 44 are powered through the distribution box. The control system achieves intelligent linkage of the motor, the return water pump 44, the compressor and the dissolved air tank 41 through multi-parameter sensing, PLC logic programming and actuator coordination. This principle is an existing technical means and will not be elaborated further.
[0036] The cleaning device 65 is a cleaning device A651, which includes a support plate A6511, a clamping plate A6512, a connecting shaft A6513, a nut A6514, and a cleaning plate A6515. The two support plates A6511 are welded to the body 1 at the tail end of the separation zone 5, serving as the basic support for the cleaning device A651. The clamping plate A6512 has connecting shafts A6513 fixed at both ends. The two connecting shafts A6513 pass through the two support plates A6511 for support and are threadedly installed by the nuts A6514, which can adjust and fix the angle of the clamping plate A6512. The cleaning plate A6515 is clamped and fixed below the clamping plate A6512. The bottom of the cleaning plate A6515 contacts the rotating scraper plate 64. The cleaning plate A6515 is made of silicone.
[0037] In the specific implementation process, when the scraper plate 64 carrying scum rotates with the conveyor chain 61 to the end of the separation zone 5, its surface enters the working area of the cleaning device 65. The silicone cleaning plate A6515, with its elastic material, adheres tightly to the surface of the scraper plate 64. Through friction and scraping, the residual scum adhering to the scraper plate 64 is peeled off. The cleaned scum falls to the end of the separation zone 5 by gravity. After the next scraper plate 64 passes through, it is pushed into the sewage discharge zone 7, preventing the scum from returning to the initial end of the separation zone 5. This achieves automatic cleaning of residual scum on the surface of the scraper plate 64, ensuring the efficient cyclic operation of the scraper plate 64.
[0038] Example 2
[0039] like Figure 5-6As shown, in this embodiment, the cleaning device 65 is a cleaning device B652, which includes a support plate B6521, a clamping plate B6522, a connecting shaft B6523, a nut B6524, a sliding groove B6525, and a cleaning plate B6526. The two support plates B6521 are welded to the body 1 at the tail end of the separation zone 5, serving as the basic support for the cleaning device B652. The clamping plate B6522 has connecting shafts B6523 fixed at both ends. The two connecting shafts B6523 pass through the two support plates B6521 and are threadedly installed by nuts B6524, which can adjust and fix the angle of the clamping plate A6512. The clamping plate B6522 has a sliding groove B6525 inside, and the cleaning plate B6526 is slidably connected to the sliding groove B6525. The bottom of the cleaning plate B6526 contacts the rotating scraper plate 64.
[0040] Multiple springs B6527 are provided inside the slide groove B6525. The top of the springs B6527 is fixed to the top of the slide groove B6525, and the bottom is fixed to the top of the cleaning plate B6526.
[0041] In practice, when the scraper blade 64 passes by, the cleaning plate B6526, elastically supported by the spring B6527, can float up and down within the groove B6525, automatically adapting to unevenness or operational vibrations on the surface of the scraper blade 64 and maintaining constant contact pressure. If hard impurities adhere to the surface of the scraper blade 64 or there is sudden jamming, the spring B6527 absorbs the impact force through compression, preventing mechanical damage to the cleaning plate B6526 or the scraper blade 64. This achieves dynamic adjustment and adaptive compensation of the cleaning pressure of the scraper blade 64, ensuring a stable and efficient cleaning process.
[0042] Example 3
[0043] like Figure 7-8 As shown, in this embodiment, the cleaning device 65 is a cleaning device C653, which includes a support plate C6531, a track groove C6532, a clamping plate C6533, a connecting shaft C6534, and a cleaning plate C6535. The two support plates C6531 are fixed on the body 1 at the tail end of the separation zone 5, serving as the basic support for the cleaning device C653. The support plate C6531 has a track groove C6532 that slopes upwards towards the tail end of the separation zone 5. The track groove C6532 is a rectangular groove. The clamping plate C6533 has a connecting shaft C6534 fixed at both ends. The connecting shaft C6534 is a square bar and slides along the track grooves C6532 on both sides to fix the angle of the clamping plate C6533. The cleaning plate C6535 is clamped and fixed below the clamping plate C6533, and the bottom of the cleaning plate C6535 contacts the rotating scraper plate 64.
[0044] A top plate C6536 is vertically fixed to the support plate C6531 at the top of the track groove C6532, and a spring C6537 is installed between the top plate C6536 and the end of the connecting shaft C6534 on the same side.
[0045] In the specific implementation process, when the scraper plate 64 contacts the cleaning plate C6535 and generates a lateral thrust, the connecting shaft C6534 slides along the inclined track groove C6532, forcing the cleaning plate C6535 to move along an inclined upward trajectory. The inclined design of the track groove C6532 causes the cleaning plate C6535 to generate a combined vertical and horizontal displacement at the moment of contact, which not only compacts and peels off the scum, but also guides the scum to slide down to the tail end in a directional manner to prevent secondary adhesion. The spring C6537 connects the top plate C6536 and the end of the connecting shaft. Under normal conditions, it is in a compressed state. When the cleaning plate C6535 is compressed, the connecting shaft C6534 slides towards the upper end of the track groove C6532, and the spring C6537 is further compressed. Through the elastic force, the constant contact pressure of the cleaning plate C6535 on the scraper plate 64 is maintained, realizing the adaptive tracking and buffer cleaning of the cleaning plate C6535, ensuring that the surface of the scraper plate 64 is clean and efficient.
[0046] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A dissolved air flotation machine, comprising a body (1), wherein a separation zone (5) is provided within the body (1), characterized in that, A slag scraper (6) is provided above the separation zone (5). The slag scraping device (6) includes a conveyor chain (61), a slag scraping motor (62), a transmission device (63), slag scraping plates (64), and a cleaning device (65). The conveyor chain (61) is installed on the machine body (1) through a shaft and bearing seat. The slag scraping motor (62) is fixed to the top of the machine body (1) and is driven by the conveyor chain (61) through the transmission device (63). Multiple slag scraping plates (64) are installed on the conveyor chain (61). A cleaning device (65) is installed on the machine body (1) at the tail end of the separation zone (5).
2. The dissolved air flotation machine according to claim 1, characterized in that, The cleaning device (65) is a cleaning device A (651). The cleaning device A (651) includes a support plate A (6511), a clamping plate A (6512), a connecting shaft A (6513), a nut A (6514), and a cleaning plate A (6515). The two support plates A (6511) are fixed on the body (1) at the tail end of the separation zone (5). The clamping plate A (6512) is fixed with a connecting shaft A (6513) at both ends. The two connecting shafts A (6513) pass through the two support plates A (6511) and are threaded through the nuts A (6514). The cleaning plate A (6515) is clamped and fixed below the clamping plate A (6512). The bottom of the cleaning plate A (6515) contacts the rotating scraper plate (64).
3. A dissolved air flotation machine according to claim 2, characterized in that, The cleaning plate A (6515) is made of silicone.
4. A dissolved air flotation machine according to claim 1, characterized in that, The cleaning device (65) is a cleaning device B (652), which includes a support plate B (6521), a clamping plate B (6522), a connecting shaft B (6523), a nut B (6524), a slide groove B (6525), and a cleaning plate B (6526). The two support plates B (6521) are fixed on the body (1) at the tail end of the separation zone (5). The clamping plate B (6522) is fixed with a connecting shaft B (6523) at both ends. The two connecting shafts B (6523) pass through the two support plates B (6521) and are threaded through the nuts B (6524). The clamping plate B (6522) has a slide groove B (6525) inside. The cleaning plate B (6526) is slidably connected to the slide groove B (6525). The bottom of the cleaning plate B (6526) contacts the rotating scraper plate (64).
5. A dissolved air flotation machine according to claim 4, characterized in that, The chute B (6525) is provided with a plurality of springs B (6527), the top of the springs B (6527) is fixed to the top of the chute B (6525), and the bottom is fixed to the top of the cleaning plate B (6526).
6. A dissolved air flotation machine according to claim 1, characterized in that, The cleaning device (65) is a cleaning device C (653), which includes a support plate C (6531), a track groove C (6532), a clamping plate C (6533), a connecting shaft C (6534), and a cleaning plate C (6535). The two support plates C (6531) are fixed on the body (1) at the tail end of the separation zone (5). The support plates C (6531) have a track groove that is inclined to the upper part of the tail end of the separation zone (5). The track groove C (6532) is a rectangular groove. The clamping plate C (6533) has connecting shafts C (6534) fixed at both ends. The connecting shafts C (6534) are square bars and are slidably connected along the two track grooves C (6532). A cleaning plate C (6535) is clamped and fixed below the clamping plate C (6533). The bottom of the cleaning plate C (6535) is in contact with the rotating scraper plate (64).
7. A dissolved air flotation machine according to claim 6, characterized in that, A top plate C (6536) is vertically fixed to the outside of the support plate C (6531) at the top of the track groove C (6532), and a spring C (6537) is installed between the top plate C (6536) and the end of the connecting shaft C (6534) on the same side.
8. A dissolved air flotation machine according to claim 1, characterized in that, Between the water inlet end of the machine body (1) and the initial section of the separation zone (5), there are sequentially arranged a flocculation zone (2), a coagulation aid zone (3), and an air flotation contact zone (4). Between the tail end of the separation zone (5) and the water outlet end of the machine body (1), there are sequentially arranged a sewage discharge zone (7) and a clear water zone (8). The upper part of the separation zone (5) is connected to the sewage discharge zone (7), and the lower part is connected to the clear water zone (8). The flocculation zone (2) is connected to an inlet (9), and the clear water zone (8) is connected to an outlet (10).
9. A dissolved air flotation machine according to claim 8, characterized in that, The dissolved air system is connected to the outside of the air flotation contact area (4). The dissolved air system includes a dissolved air tank (41), a microbubble releaser (42), a return water pipe (43), and a return water pump (44). The dissolved air tank (41) is fixed to the outside of the machine body (1). The microbubble releaser (42) connected to the dissolved air tank (41) is located at the bottom of the air flotation contact area (4). The dissolved air tank (41) is connected to the clear water area (8) by a return water pipe (43). A return water pump (44) is installed on the return water pipe (43).
10. A dissolved air flotation machine according to claim 8, characterized in that, The bottom of the separation zone (5) is equipped with a separation zone drain outlet (51), and the bottom of the discharge zone (7) is equipped with a discharge zone drain outlet (71).