Negative pressure screening device for separating sewage and impurities

Abstract

The present application relates to the technical field of sewage treatment, and particularly relates to a negative pressure screening device for sewage and impurities separation, which comprises a negative pressure separation chamber, a screening membrane arranged in the middle of the negative pressure separation chamber, a water-gas separation tank arranged below the negative pressure separation chamber and communicated with the negative pressure separation chamber, a water flow stabilizing tank for controlling the flow of sewage flowing into the negative pressure separation chamber from the upper part of the negative pressure separation chamber, a vacuum pump connected to the water-gas separation tank, an arc-shaped support net plate arranged in the negative pressure separation chamber and having a downward concave arc-shaped structure, the edge of the arc-shaped support net plate being fixed to the inner wall of the negative pressure separation chamber, and the upper surface of the arc-shaped support net plate being used for supporting the screening membrane, and a winding assembly arranged at both ends of the screening membrane, the screening membrane extending from the positions of the two long holes and being wound through the winding assembly. The present application realizes the continuous operation of sewage and impurity screening by moving the screening membrane in the negative pressure separation chamber and accelerating the filtration of sewage by negative pressure.

Description

Technical Field

[0001] This invention relates to the technical field of wastewater treatment, and specifically to a negative pressure screening device for separating wastewater and impurities. Background Technology

[0002] In the field of wastewater treatment technology, screening and filtration devices are key equipment for removing suspended particles, impurities, and filter media from water. Their performance directly affects the stable operation of subsequent treatment units and the quality of effluent. Highly efficient, flexible, and clogging-resistant filtration equipment is crucial for improving wastewater treatment efficiency and reducing operation and maintenance costs. Traditional screening methods, such as screens, are prone to clogging when processing fine impurities smaller than 0.05mm. This leads to a sharp decline in filtration efficiency, increased equipment operating resistance, and frequent shutdowns for cleaning or filter media replacement. This severely restricts the continuity and automation of the wastewater treatment process and increases operating and maintenance costs.

[0003] Chinese patent CN214130492U discloses a wastewater filter box, including a box body and a composite filter screen. The box body is open at both the top and bottom. A horizontally arranged annular mounting ring is provided on the inner wall of the box body. The composite filter screen is horizontally mounted on the annular mounting ring, and the outer edge of the composite filter screen is flush with the inner wall of the box body. The composite filter screen includes an upper filter plate, a lower filter plate, and a mounting frame. The mounting frame is a horizontally arranged rectangular frame. Both the upper and lower filter plates are horizontally mounted within the mounting frame, with the upper filter plate directly above the lower filter plate. The composite filter screen is horizontally mounted on an annular mounting ring, with the outer edge of the mounting frame fitting snugly against the inner wall of the housing. The edge of the upper filter plate is fixedly connected to the inner wall of the mounting frame. The inner wall of the mounting frame also has a horizontal annular adjustment groove located below the upper filter plate. The edge of the lower filter plate extends into the annular adjustment groove, creating a gap between the lower filter plate and the annular adjustment groove, forming an adjustment area. The lower filter plate and the annular adjustment groove are fitted together with a clearance. By adjusting the position of the lower filter plate within the annular adjustment groove, the perforations of the upper and lower filter plates can be aligned or staggered. A collection hopper and discharge pipe are located at the bottom of the housing to collect the separated filter media. By adjusting the alignment of the perforations of the upper and lower filter plates, the particle size of the separated impurities can be adjusted.

[0004] However, composite filter screens rely entirely on gravity to fall naturally during the wastewater filtration process, resulting in low efficiency in filtering fine particles. Especially when dealing with impurities with a particle size of less than 0.1mm, they are prone to being forced to stop operation for cleaning due to screen hole blockage, making continuous automatic screening impossible. Summary of the Invention

[0005] This invention provides a negative pressure screening device for separating wastewater and impurities, aiming to solve the problem in the prior art of filtering fine particles in wastewater and the inability to perform continuous automatic screening operations.

[0006] The negative pressure screening device for separating wastewater and impurities according to the present invention includes a negative pressure separation chamber.

[0007] A screening membrane is disposed in the middle of the negative pressure separation chamber, dividing the negative pressure separation chamber into upper and lower parts;

[0008] A water-gas separator is located below the negative pressure separation chamber and is connected to the negative pressure separation chamber;

[0009] A flow stabilizing tank is used to control the flow rate of sewage flowing into the negative pressure separation chamber from the top.

[0010] A vacuum pump is connected to the water-gas separator tank;

[0011] An arc-shaped support mesh plate is disposed in the negative pressure separation chamber. It has a downward concave arc-shaped structure and its edge is fixed to the inner wall of the negative pressure separation chamber. The upper surface of the arc-shaped support mesh plate is used to support the screening membrane. The screening membrane is disposed along the arc-shaped surface of the arc-shaped support mesh plate, and elongated holes are provided at the connection between the negative pressure separation chamber and the two ends of the arc-shaped support mesh plate.

[0012] A winding assembly is disposed at both ends of the screening membrane, the screening membrane extending from the two elongated holes and being wound around the winding assembly.

[0013] Its effect is as follows: When sewage enters the flow stabilization tank, it flows at a relatively uniform flow rate from the upper part of the negative pressure separation chamber to the negative pressure separation chamber under the action of the flow stabilization tank. Under the action of negative pressure, the sewage can quickly pass through the screening membrane, leaving impurities in the sewage on the upper surface of the screening membrane. Through continuous airflow, the sewage is continuously filtered through the screening membrane. The filtered water enters the water-air separation tank. The arc-shaped support mesh plate is set with a concave arc structure, so that the screening membrane adheres to the upper surface of the arc-shaped support mesh plate under the negative pressure provided by the vacuum pump, maintaining the shape of the screening membrane. When impurities on the screening membrane affect its permeability, the winding assembly moves the screening membrane to one side, restoring the permeability of the screening membrane on the upper part of the arc-shaped support mesh plate. Thus, sewage can be continuously filtered on the screening membrane, and fine particles in the sewage can also be quickly separated under the action of negative pressure, thereby realizing the screening operation of sewage.

[0014] Preferably, the water flow stabilizing tank is equipped with an overflow device inside, and a sewage outlet pipe for connecting to the negative pressure separation chamber is provided at the position of the overflow device on the water flow stabilizing tank. The overflow device includes a baffle plate, an overflow plate, and a float. The baffle plate is fixed to the inner wall of the water flow stabilizing tank, and the baffle plate forms a partition chamber at the position where the sewage outlet pipe is located on the water flow stabilizing tank. A weir groove is formed on the baffle plate. The overflow plate is slidably connected to the baffle plate and blocks the position of the weir groove. The float is fixed on the overflow plate.

[0015] Its effect is as follows: a weir groove is opened on the partition plate. When sewage enters the water flow stabilization tank, the float will drive the overflow plate to move with the change of liquid level, so that the height of the upper part of the overflow plate is adjusted, thereby controlling the opening of the weir groove, so as to control the flow rate of water entering the partition chamber, and thus the flow rate of sewage outlet pipe can be controlled without power.

[0016] Preferably, the winding assembly includes a drum and a drive motor. Impurity collection chambers are provided on both sides of the negative pressure separation chamber. The two ends of the drum are rotatably mounted on the impurity collection chambers. The drive motor is fixed on the impurity collection chambers. A reducer is connected to the output shaft of the drive motor. The reducer is connected to the drum.

[0017] Its effect is that the drive motor drives the drum to rotate, so that one of the two winding components winds up the screening membrane while the other winds up the screening membrane synchronously, thereby controlling the movement of the screening membrane. The two winding components can be switched between winding and unwinding so that the screening membrane can move back and forth.

[0018] Preferably, the impurity collection chamber is provided with a scraping assembly, which includes a fixing frame, a mounting guide rod, a force-applying component, and a scraper. The fixing frame is fixed in the impurity collection chamber, and the scraper is arranged along the tangent direction of the cylindrical screening membrane wound on the roll. One end of the mounting guide rod is vertically fixed to the surface of the scraper, and the other end is slidably connected to the fixing frame. The force-applying component drives the scraper to move towards the screening membrane.

[0019] Its effect is that the scraper moves towards the screening membrane under the action of the force-applying component, so that the scraper sticks to the screening membrane. When the screening membrane is in the winding state, the impurities on the screening membrane are removed under the action of the scraper. With the help of two winding components, the screening membrane can be reused.

[0020] Preferably, the impurity collection chamber is provided with a pushing component, which is mounted on a fixed frame and is used to push the scraper to move along the length direction of the mounting guide rod, and to keep the scraper tangent to the gradually increasing cylindrical screening membrane during the winding process of the screening membrane.

[0021] Its effect is to push the component to control the scraper to move along the mounting guide rod, so that the scraper automatically adjusts as the screening membrane is rolled up, so as to maintain a small friction between the scraper and the screening membrane and reduce the damage of the scraper to the screening membrane.

[0022] Preferably, the pushing assembly includes a pushing frame, a guide rod, a first rack, a second rack, and an intermediate gear. The guide rod is fixedly connected to the pushing frame and is arranged parallel to the mounting guide rod. The first rack is fixed on the pushing frame, the second rack is fixed on the scraper, and the intermediate gear is rotatably mounted on the fixed frame. The first rack and the second rack are parallel to the guide rod and mesh with the intermediate gear.

[0023] Preferably, the push frame is rotatably connected to a drive roller, which is used to abut against the outer peripheral wall of the wound screening film. The axis of the drive roller is parallel to the axis of the roll, and the center line of the drive roller, the center line of the roll, and the edge of the scraper that is tangent to the roll are all on the same plane.

[0024] Its effect is that the drive roller abuts against the outer peripheral wall of the winding screening film. As the radius of the screening film gradually increases during the winding process, it will push the drive roller away from the center of the roll. Thus, the scraper can be pushed in opposite directions by the first gear, the second gear and the intermediate gear at the same time, thereby ensuring that the scraper is always tangent to the winding screening film.

[0025] Preferably, a vertical airflow pipe is fixedly installed at the top of the negative pressure separation chamber, and a water distributor is installed inside the airflow pipe. The water distributor includes a mounting ring, a rotating shaft, a drive blade, and a rotating cone. The rotating shaft is vertically installed inside the mounting ring, which is used to fix it to the airflow pipe. The drive blade is coaxially fixed to the rotating shaft and located inside the airflow pipe. The top end of the rotating cone is coaxially fixed to the lower end of the rotating shaft, and multiple plates are provided on the outer peripheral wall of the rotating cone.

[0026] Its effect is that the drive blades are located inside the airflow pipe, and the airflow inside the airflow pipe can drive the drive blades, thereby causing the rotating shaft and the rotating cone to rotate simultaneously. When the sewage falls onto the rotating cone, the rotation of the rotating cone can distribute the sewage more evenly into the negative pressure separation chamber, which is beneficial for the screening membrane to filter sewage.

[0027] Preferably, the interior of the water-gas separator is provided with a vertical plate, the upper part of which is spaced apart from the top of the water-gas separator. An extension pipe and a drain pipe are respectively provided on both sides of the vertical plate. The drain pipe is connected to the bottom of the water-gas separator, and the extension pipe is connected to the top of the water-gas separator for connecting to the negative pressure separation chamber. The lower end of the extension pipe is higher than the upper edge of the vertical plate, and the height difference is 2-3 cm.

[0028] Its effect is that the lower end of the extension tube is 2-3cm higher than the upper edge of the vertical plate. As the airflow carries water droplets down the extension tube, the water droplets can be collected into the water-air separation tank under centrifugal force. The liquid level below the extension tube can be controlled by the vertical plate.

[0029] Preferably, the bottom of the water flow stabilizing tank is provided with stirring blades, which are driven by a motor.

[0030] By adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0031] This invention uses a water flow stabilizing tank to evenly flow wastewater into a negative pressure separation chamber. Under negative pressure, the wastewater quickly passes through a screening membrane, leaving impurities on its upper surface. An arc-shaped support mesh is designed with a concave arc structure, allowing the screening membrane to adhere to its upper surface under the negative pressure provided by a vacuum pump, maintaining its shape. A winding assembly moves the screening membrane to one side, restoring permeability to the upper portion of the membrane on the arc-shaped support mesh. This allows for continuous filtration of wastewater through the screening membrane, and even fine particles can be quickly separated under negative pressure, thus enabling wastewater screening. A scraper moves towards the screening membrane under the action of a force-applying component, adhering to it. When the membrane is in a winding state, impurities are removed by the scraper. The two winding assemblies allow the screening membrane to be reused. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the external shape of the negative pressure screening device for separating wastewater and impurities according to the present invention.

[0033] Figure 2 This is a schematic diagram of the internal structure of the negative pressure separation chamber in an embodiment of the present invention;

[0034] Figure 3 yes Figure 2 A cross-sectional view along the AA direction;

[0035] Figure 4 This is a schematic diagram of the internal structure of the water flow stabilizing tank in an embodiment of the present invention;

[0036] Figure 5 yes Figure 3 Enlarged view of section B;

[0037] Figure 6 This is a schematic diagram of the water equalizer in an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the connection structure of the driving component in an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram showing the arrangement of the first and second racks in an embodiment of the present invention.

[0040] Figure label:

[0041] 1. Negative pressure separation chamber; 11. Arc-shaped support mesh plate; 12. Long strip hole; 2. Screening membrane; 3. Water flow stabilizing tank; 31. Sewage inlet pipe; 32. Vent pipe; 33. Sewage outlet pipe; 34. Agitator blades; 35. Overflow device; 351. Baffle plate; 352. Overflow plate; 353. Float ball; 354. Weir; 355. Separation chamber; 356. Guide channel; 4. Water-air separator; 41. Vacuum pump; 42. Drain pipe; 43. Vertical plate; 44. Extension pipe; 45. Airflow pipe; 5. Roll 51. Winding assembly; 52. Drum; 6. Drive motor; 7. Impurity collection chamber; 8. Collection box; 9. Slag scraping assembly; 10. Fixing frame; 11. Mounting guide rod; 12. Force application component; 13. Scraper; 14. Water distributor; 15. Mounting ring; 16. Rotating shaft; 17. Drive blade; 18. Rotating cone; 19. Bushing; 10. Plate; 11. Pushing assembly; 12. Pushing frame; 13. Guide rod; 14. Drive roller; 15. First rack; 16. Second rack; 17. Intermediate gear. Detailed Implementation

[0042] The following is combined with Figures 1 to 8 Embodiments of the present invention will be described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0043] This embodiment discloses a negative pressure screening device for separating wastewater and impurities, such as... Figure 1 and Figure 2 As shown, the device includes a negative pressure separation chamber 1, a screening membrane 2, and a water flow stabilizing tank 3. A water-air separation tank 4 is located below the negative pressure separation chamber 1, and the upper part of the negative pressure separation chamber 1 is connected to the water flow stabilizing tank 3. The screening membrane 2 is located in the middle of the negative pressure separation chamber 1, and a vacuum pump 41 is connected to the water-air separation tank 4. During the vacuum pump 41's pumping process, a negative pressure is formed inside the water-air separation tank 4. At this time, the airflow passes from top to bottom through the screening membrane 2, which separates the negative pressure separation chamber 1 vertically. Wastewater and impurities flow out of the water flow stabilizing tank 3 and into the negative pressure separation chamber 1, first falling onto the screening membrane 2. Then, as the airflow passes through the screening membrane 2, impurities are retained on the screening membrane 2. The wastewater flows downward into the water-air separation tank 4, where it is separated and temporarily stored. A drain pipe 42 is connected to the bottom of the water-air separation tank 4, which discharges the separated water for subsequent treatment. The screening membrane 2 is mainly used to remove impurity particles with a diameter of 0.01-0.05mm from sewage. Since the removal of such impurity particles by the screen is slow and the treatment efficiency is low, the sewage can be quickly drawn through the screening membrane 2 by negative pressure to improve the sewage treatment efficiency.

[0044] refer to Figure 2An arc-shaped support mesh plate 11 is installed inside the negative pressure separation chamber 1. The arc-shaped support mesh plate 11 has a downwardly concave arc structure. The edge of the arc-shaped support mesh plate 11 is fixed to the inner wall of the negative pressure separation chamber 1, and the connection can be made by welding. The upper surface of the arc-shaped support mesh plate 11 is used to support the screening membrane 2. The screening membrane 2 is arranged along the arc surface of the arc-shaped support mesh plate 11, and elongated holes 12 are opened at the connection between the negative pressure separation chamber 1 and the arc-shaped ends of the arc-shaped support mesh plate 11, so that the screening membrane 2 extends out of the negative pressure separation chamber 1 from the two elongated holes 12. A winding assembly 5 is provided at both ends of the screening membrane 2, and the winding assembly 5 is used to wind the screening membrane 2. Impurity collection chambers 6 are also provided on both sides of the negative pressure separation chamber 1. The winding assembly 5 is located in the impurity collection chamber 6, and a scraper assembly 7 is also provided in the impurity collection chamber 6. The scraper assembly 7 is used to remove impurities from the screening membrane 2. A collection box 61 is located below the scraper assembly 7. Impurities cleaned by the scraper assembly 7 fall into the collection box 61 for collection and subsequent processing. During use, negative pressure draws the screening membrane 2 onto the upper surface of the arc-shaped support mesh plate 11, allowing gas to flow downwards through the screening membrane 2 and the arc-shaped support mesh plate 11. The arc-shaped support mesh plate 11 stabilizes the screening membrane 2 and improves its strength. When there are many impurities on the screening membrane 2, the screening membrane 2 is wound onto one winding assembly 5 while the screening membrane 2 on the other winding assembly 5 is unwound. This allows for quick replacement of the screening membrane 2 on the arc-shaped support mesh plate 11, restoring the membrane's permeability. During the winding process of the winding assembly 5, the scraper assembly 7 removes impurities from the screening membrane 2, which fall into the collection box 61. After the screening membrane 2 on a winding assembly 5 has been unwound multiple times, it can be wound up by reversing the operation, so that the screening membrane 2 can be reciprocated multiple times under the action of the two winding assemblies 5, making it convenient for the screening membrane 2 to be reused.

[0045] refer to Figure 3The water-gas separator 4 is cylindrical with its axis horizontally positioned. Inside the water-gas separator 4 is a vertically mounted plate 43, the edges of which are welded and sealed to the inner wall of the water-gas separator 4. The upper part of the plate 43 is spaced apart from the interior of the water-gas separator 4. An extension pipe 44 is connected to the water-gas separator 4, vertically penetrating the upper side wall of the water-gas separator 4. The upper end of the extension pipe 44 is connected to the lower part of the negative pressure separation chamber 1 via a flange, while the lower end is inside the water-gas separator 4. The height of the lower end of the extension pipe 44 is greater than the height of the upper edge of the plate 43, with a height difference of 2-3 cm between the two. Water flowing down from the extension pipe 44 collects on one side of the plate 43, overflowing to the other side of the plate 43 when it exceeds its upper edge. Drain pipe 42 and extension pipe 44 are located on both sides of vertical plate 43, respectively. Overflowing water is discharged from water-air separator 4 through drain pipe 42. Vacuum pump 41 is connected to the upper part of water-air separator 4 through pipeline. When the airflow in extension pipe 44 carries water droplets downward, it turns at the lower end of extension pipe 44 to generate centrifugal force, causing the water droplets to fall onto the water surface, thus achieving the purpose of water-air separation. Even if the amount of water discharged by drain pipe 42 changes, it will not affect the liquid level on the side of vertical plate 43 where extension pipe 44 is located, thereby ensuring the effect of water-air separation.

[0046] refer to Figure 4 and Figure 5The water flow stabilizing tank 3 has a sewage inlet pipe 31 at the top and a vent pipe 32 at the bottom, with a manual valve installed on the vent pipe 32. A sewage outlet pipe 33 is located on the side wall of the water flow stabilizing tank 3, positioned at the top. A stirring blade 34 is located at the bottom of the water flow stabilizing tank 3, driven by a motor to ensure all sewage and impurities in the water flow stabilizing tank 3 flow out, preventing sedimentation and ensuring stable operation. An overflow device 35 is located inside the water flow stabilizing tank 3, corresponding to the position of the sewage outlet pipe 33. The overflow device 35 includes a baffle plate 351, an overflow plate 352, and a float 353. The baffle plate 351 is welded to the inner wall of the water flow stabilizing tank 3, forming a partition chamber 355 at the position of the sewage outlet pipe 33. The upper edge of the baffle plate 351 is located above the sewage outlet pipe 33. A weir trough 354 is formed on one side of the partition 351, extending downwards from the upper edge of the partition 351. An overflow plate 352 is parallel to the side of the partition 351 where the weir trough 354 is formed. Guide grooves 356 are provided at the two vertical edges of the overflow plate 352, fixed to the partition 351. The overflow plate 352 is slidably connected to the partition 351 via the guide grooves 356, with one side of the overflow plate 352 in contact with the surface of the partition 351, thus blocking the weir trough 354. A float 353 is fixed to the upper part of the overflow plate 352, positioned on the side of the overflow plate 352 away from the partition 351. When the water flow stabilizing tank 3 contains wastewater, the stirring blades 34 agitate the wastewater, primarily affecting the lower part of the water flow stabilizing tank 3, with minimal impact on the upper surface of the wastewater. When wastewater enters through the wastewater inlet pipe 31, causing the liquid level to rise, the float 353 also rises with the liquid level, thereby controlling the flow rate of wastewater flowing through the weir trough 354 and stabilizing the flow rate of wastewater discharged through the wastewater outlet pipe 33. With a stable flow rate, the wastewater enters the negative pressure separation chamber 1, making it easier to spread evenly on the screening membrane 2. Furthermore, the smaller volume of wastewater allows for easier airflow through the screening membrane 2, and the wastewater can also pass through the screening membrane 2 more quickly with the airflow.

[0047] refer to Figure 3 and Figure 6A vertical airflow pipe 45 is fixed to the top of the negative pressure separation chamber 1. The middle part of the airflow pipe 45 is connected to the sewage outlet pipe 33 via a flange. The lower end of the airflow pipe 45 is connected to the negative pressure separation chamber 1 via a flange, and a water distributor 8 is installed at the connection between the lower end of the airflow pipe 45 and the negative pressure separation chamber 1. The water distributor 8 is used to distribute the outflowing sewage more evenly in the negative pressure separation chamber 1, so that the sewage spreads on the screening membrane 2. The water distributor 8 includes a mounting ring 81, a rotating shaft 82, a drive blade 83, and a rotating cone 84. The water distributor 8 is fixed between the airflow pipe 45 and the negative pressure separation chamber 1 by the mounting ring 81. The center of the mounting ring 81 is located at the bushing 85, and the outer wall of the bushing 85 is spaced apart from the inner wall of the mounting ring 81 to allow airflow and wastewater to pass between the bushing 85 and the mounting ring 81. The rotating shaft 82 is rotatably connected to the bushing 85 by a bearing and is vertically arranged. The drive blade 83 is coaxially fixed to the upper end of the rotating shaft 82 and is located inside the airflow pipe 45. The rotating cone 84 is conical in shape, and multiple plates 86 are provided on its outer peripheral wall, inclined along the side wall of the rotating cone 84. The rotating cone 84 is coaxially fixed to the rotating shaft 82, and the top of the rotating cone 84 is connected to the rotating shaft 82. When the drive blade 83 rotates under the push of the airflow in the airflow pipe 45, the rotating shaft 82 and the rotating cone 84 rotate simultaneously. When the sewage flows into the rotating cone 84 through the middle of the airflow pipe 45, the sewage will be dispersed outward, so that the sewage can be more evenly distributed on the screening membrane 2 to prevent sewage from accumulating.

[0048] refer to Figure 1 and Figure 7 The winding assembly 5 includes a drum 51 and a drive motor 52. The two ends of the drum 51 are rotatably mounted on the side walls of the impurity collection chamber 6. The drive motor 52 is fixed to the outer wall of the impurity collection chamber 6. A reducer is connected to the output shaft of the drive motor 52, and the reducer is connected to the drum 51. The drive motor 52 drives the drum 51 to rotate through the reducer. In this embodiment, the drive motor 52 can rotate in both directions. When the winding assembly 5 winds up the screening membrane 2, the drive motor 52 of one winding assembly 5 rotates forward, while the drive motor 52 of the other winding assembly 5 rotates in reverse, causing the two winding assemblies 5 to cooperate in transferring the screening membrane 2 onto one drum 51, thereby winding it onto the drum 51.

[0049] refer to Figure 7Since impurities accumulate on the upper surface of the screening membrane 2 during use, it is necessary to remove these impurities using the scraping assembly 7. The scraping assembly 7 includes a fixing frame 71, a mounting guide rod 72, a force-applying component 73, and a scraper 74. The fixing frame 71 is fixed to the inner wall of the impurity collection chamber 6. The scraper 74 is positioned along the tangent of the cylindrical screening membrane 2 wound on the roll 51, and gradually tilts downwards towards the direction away from the roll 51. The mounting guide rod 72 is vertically fixed to the lower surface of the scraper 74, and the upper surface of the scraper 74 guides the scraped impurities into the collection box 61. The mounting guide rod 72 is slidably connected to the fixing frame 71, and its sliding direction is parallel to the mounting guide rod 72. In this embodiment, the force-applying component 73 is a spring, which is sleeved on the mounting guide rod 72. One end of the spring abuts against the fixing frame 71, and the other end abuts against a nut fixed to the end of the mounting guide rod 72. The spring force drives the mounting guide rod 72 to slide, causing the scraper 74 to move closer to the screening membrane 2 on the outer wall of the drum 51. As the drum 51 rotates, the scraper 74 can clean impurities from the screening membrane 2 by adhering to its surface. The length of the mounting guide rod 72 is parallel to the radial line on the drum 51 passing through the point of tangency between the scraper 74 and the drum 51. This ensures that as the screening membrane 2 is wound up, its radius on the drum 51 gradually increases. Even after the mounting guide rod 72 slides, the scraper 74 remains tangential to the wound screening membrane 2. This tangential arrangement of the scraper 74 to the screening membrane 2 is beneficial for cleaning impurities.

[0050] refer to Figure 7 and Figure 8A pushing assembly 9 is installed on the fixed frame 71 to move the scraper 74 along the length direction of the mounting guide rod 72. The pushing assembly 9 can be a linear module, a hydraulic cylinder, or an electric cylinder. The pushing assembly 9 pushes the scraper 74 away from the drum 51 as the diameter of the screening membrane 2 gradually increases. This ensures that the scraper 74 is tangential to the screening membrane 2 without abutting against it, thereby reducing the friction between the scraper 74 and the screening membrane 2 and improving the service life of the screening membrane 2. In this embodiment, the pushing assembly 9 includes a pushing frame 91, a guide rod 92, a drive roller 93, a first rack 94, a second rack 95, and an intermediate gear 96. The guide rod 92 is fixedly connected to the pushing frame 91 and is arranged parallel to the mounting guide rod 72. The drive roller 93 is rotatably connected to the pushing frame 91. The axis of the drive roller 93 is parallel to the axis of the drum 51. The center line of the drive roller 93, the center line of the drum 51, and the edge where the scraper 74 is tangential to the drum 51 are all on the same plane. When the screening membrane 2 is wound on the roll 51, the drive roller 93 abuts against the wound screening membrane 2 and moves as the diameter of the wound screening membrane 2 increases. The first rack 94 and the second rack 95 are both arranged parallel to the guide rod 92. The first rack 94 is fixed to the push frame 91, and the second rack 95 is fixed to the scraper 74. The intermediate gear 96 is rotatably mounted on the fixed frame 71. The first rack 94 and the second rack 95 both mesh with the intermediate gear 96 and are located on opposite sides of the center line of the intermediate gear 96. As the drive roller 93 moves along the radial line of the drum 51 as the diameter of the screening membrane 2 increases, the first rack 94 moves with the push frame 91, thereby pushing the second rack 95 through the intermediate gear 96. The scraper 74 on the second rack 95 moves away from the center of the drum 51 in the opposite direction, so that the position of the scraper 74 can change with the amount of screening membrane 2 being wound up, ensuring that the scraper 74 can clean the impurities on the screening membrane 2 without causing excessive friction to the screening membrane 2.

[0051] The working process of this embodiment is as follows: Wastewater first enters the water flow stabilizing tank 3 through the wastewater inlet pipe 31. The stirring blades 34 in the water flow stabilizing tank 3 continuously stir to prevent impurities from settling and ensure that the wastewater mixture is uniform. The float ball 353 controls the position of the overflow plate 352, so that the overflow plate 352 adjusts the opening of the weir trough 354, thereby controlling the wastewater to flow out stably from the wastewater outlet pipe 33. Even if the wastewater flow fluctuates during the inflow process, the outflow rate tends to be constant, creating conditions for subsequent uniform screening. The wastewater with a stable flow rate enters the airflow pipe 45. The downward airflow pushes the drive blades 83 to rotate, thereby driving the rotating shaft 82 and the rotating cone 84 to rotate together. When the wastewater falls onto the rotating cone 84, it will be evenly sprinkled onto the screening membrane 2 in the negative pressure separation chamber 1 by the dispersing action of the plates 86, thereby forming a thin and uniform wastewater layer. Vacuum pump 41 continuously draws air from the top of water-gas separator 4. Under the action of pressure difference, the airflow passes through the screening membrane 2 from top to bottom. The wastewater spread on the screening membrane 2 is accelerated through the screening membrane 2 by the airflow, while the separated water enters the extension pipe 44 along with the airflow. The airflow carrying water droplets enters the water-gas separator 4 through the extension pipe 44 and impacts the liquid surface, thereby achieving water-gas separation. The screened impurities continuously accumulate on the upper surface of the screening membrane 2, causing the permeability of the screening membrane 2 to decrease. When cleaning is required, the winding assembly 5 is activated. One drive motor 52 drives one roller 51 to wind up the screening membrane 2, while the other roller 51 unwinds simultaneously, thus allowing for quick replacement of a section of the screening membrane 2 in the negative pressure separation chamber 1. When the screening membrane 2 is wound through the scraping assembly 7, the scraper 74, under the action of the spring, is always tangential to the peripheral wall of the wound screening membrane 2, thereby scraping off the impurities attached to the upper surface of the screening membrane 2. The impurities fall into the collection box 61 below for collection.

[0052] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A negative pressure screening device for separating sewage and impurities, comprising a negative pressure separation chamber, characterized in that, Also include: Screening membrane, arranged in the middle of the negative pressure separation chamber, and separates the negative pressure separation chamber into two parts; Water gas separation tank, arranged below the negative pressure separation chamber, and communicated with the negative pressure separation chamber; Water flow stabilizing tank for controlling the flow of sewage from the upper part of the negative pressure separation chamber to the negative pressure separation chamber; Vacuum pump connected to the water gas separation tank; Arc-shaped support net plate, arranged in the negative pressure separation chamber, the whole is downward concave arc structure, its edge is fixed with the inner wall of the negative pressure separation chamber, the upper surface of the arc-shaped support net plate is used for supporting the screening membrane, the screening membrane is arranged along the arc surface of the arc-shaped support net plate, and long strip holes are arranged at the positions of the two ends of the negative pressure separation chamber and the arc-shaped support net plate. Winding assembly, arranged at the two ends of the screening membrane, the screening membrane is stretched out from the position of the two long strip holes and wound through the winding assembly; The winding assembly includes a winding drum and a driving motor, the two sides of the negative pressure separation chamber are provided with impurity collecting chambers, the two ends of the winding drum are rotatably arranged on the impurity collecting chambers, the driving motor is fixed on the impurity collecting chambers, a speed reducer is connected to the output shaft of the driving motor, and the speed reducer is connected with the winding drum. The impurity collecting chamber is provided with a slag scraping assembly, the slag scraping assembly includes a fixed frame, a mounting guide rod, a force applying member and a scraper, the fixed frame is fixed in the impurity collecting chamber, the scraper is arranged along the tangent direction of the cylindrical screening membrane wound on the winding drum, one end of the mounting guide rod is fixed perpendicularly on the surface of the scraper, and the other end is slidably connected to the fixed frame, and the force applying member drives the scraper to move towards the screening membrane. The impurity collecting chamber is provided with a pushing assembly, the pushing assembly is arranged on the fixed frame and is used for pushing the scraper to move along the length direction of the mounting guide rod, and the pushing assembly keeps the scraper tangent to the gradually increasing cylindrical screening membrane during the winding process of the screening membrane. The pushing assembly includes a pushing frame, a guide rod, a first rack, a second rack and an intermediate gear, the guide rod is fixedly connected with the pushing frame, and the guide rod is arranged parallel to the mounting guide rod, the first rack is fixed on the pushing frame, the second rack is fixed on the scraper, and the intermediate gear is rotatably arranged on the fixed frame, the first rack and the second rack are parallel to the guide rod, and the first rack and the second rack are meshed with the intermediate gear. The pushing frame is rotatably connected with a driving roller, the driving roller is used for abutting against the outer peripheral wall of the wound screening membrane, the axis of the driving roller is parallel to the axis of the winding drum, and the center line of the driving roller, the center line of the winding drum and the edge of the scraper tangent to the winding drum are located on the same plane.

2. The negative pressure screening apparatus for separating sewage and impurities according to claim 1, characterized in that, The water flow stabilizing tank is provided with an overflow device, a sewage outlet pipe for connecting the negative pressure separation chamber is arranged on the water flow stabilizing tank at the position of the overflow device, the overflow device includes a partition plate, an overflow plate and a floating ball, the partition plate is fixed on the inner wall of the water flow stabilizing tank, the partition plate divides the position of the sewage outlet pipe of the water flow stabilizing tank into a separate chamber, a weir groove is arranged on the partition plate, the overflow plate is slidably connected to the partition plate, the overflow plate is arranged at the position of the weir groove, and the floating ball is fixed on the overflow plate.

3. The negative pressure screening apparatus for separating sewage and impurities according to claim 1, characterized in that, The vertical airflow pipe is internally provided with a water uniformizer, which comprises a mounting ring, a rotating shaft, a driving blade and a rotating cone.

4. The negative pressure screening apparatus for separating sewage and impurities according to claim 1, wherein, The water-gas separation tank is internally provided with a vertical plate, the upper portion of the vertical plate is spaced apart from the top of the water-gas separation tank, the two sides of the vertical plate are respectively provided with an extension pipe and a drain pipe, the drain pipe is connected to the bottom of the water-gas separation tank, the extension pipe is connected to the top of the water-gas separation tank for connecting the negative pressure separation chamber, the lower end of the extension pipe is higher than the upper edge of the vertical plate, and the height difference is 2-3 cm.

5. The negative pressure screening apparatus for separating sewage and impurities according to claim 2, wherein, The water flow stabilizing tank is provided with stirring blades at the bottom, which are driven by a motor.

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