Backwashing type efficient filtering equipment for preparing desalted water

Abstract

The invention discloses backwashing type efficient filtering equipment for desalted water preparation, and relates to the field of backwashing equipment of water treatment devices, the backwashing type efficient filtering equipment for desalted water preparation comprises a barrel body, a partition plate divided cavity in the barrel body, a flow dividing pipe group and a multi-layer concentric aeration pipe group arranged on a partition plate convex part, and air nozzles distributed in a staggered manner and sleeved with a housing capable of irregularly swinging, the housing, the blocking ball, the blocking shoulder and the receding groove form a limiting structure. During normal filtration, raw water is uniformly distributed to the sand bed through the water distribution disc, and filtered clear water is led out from the lower cavity; during backwashing, air flow is sprayed out through the air nozzle after passing through the flow dividing pipe group and the aeration pipe group, and the housing is driven to swing to realize full-barrel-diameter dead-corner-free aeration. Through cooperation of a specific structure, the regeneration efficiency and filtering stability of the filter material are improved, the anti-blocking effect of the air tap is excellent, operation and maintenance are convenient, the comprehensive production cost is reduced, and the device is suitable for the field of industrial desalted water preparation.

Description

Technical Field

[0001] This invention relates to the field of backwashing equipment in water treatment devices, and more particularly to a backwashable high-efficiency filtration device for desalination preparation. Background Technology

[0002] Filtration, as a core pretreatment / advanced treatment step in the desalination process, aims to remove impurities such as suspended solids, colloidal particles, and salt crystal precursors from the raw water. This reduces the processing load on subsequent desalination units (such as reverse osmosis and electrostatic desalination) and extends the service life of these core equipment. Therefore, the filtration efficiency, backwashing and regeneration effect, operational stability, and ease of maintenance of the filtration equipment directly determine the overall operating cost and effluent quality of the desalination system.

[0003] Currently, the filtration equipment widely used in the coarse filtration stage of industrial desalination preparation, i.e., the front-end filtration method, is mainly deep filtration devices such as sand filter tanks and activated carbon filters. These devices mostly adopt the working mode of trapping impurities in the filter media layer. That is, during normal filtration, the raw water penetrates the filter media layer (such as quartz sand, anthracite, etc.) from top to bottom, and the impurities are trapped by the filter media. When the filter media layer has increased filtration resistance and decreased filtration efficiency due to the accumulation of impurities, the impurities trapped in the filter media layer are stripped off and discharged with the backwash water by the reverse water flow (i.e., water backwash) or the combination of "water backwash + aeration disturbance", thus realizing the regeneration of the filter media.

[0004] However, existing aeration devices mostly employ fixed-direction aeration pipes and nozzles, such as straight aeration pipes or single annular aeration pipes. The nozzles are oriented in a fixed direction and unevenly distributed, resulting in aeration airflow covering only localized areas and creating numerous aeration dead zones. During backwashing, impurities easily remain in areas of the filter media that are not disturbed by aeration. Over long-term operation, this leads to filter media caking and filtration channel blockage, significantly reducing filtration efficiency and causing fluctuations in effluent quality, failing to meet the feed requirements of subsequent desalination processes. Some equipment attempts to improve coverage by increasing the number of aeration pipes, but it is still difficult to achieve uniform aeration across the entire tank diameter without dead zones. Furthermore, mutual interference between airflows can cause localized excessively strong or weak airflows, further exacerbating the uneven fluidization of the filter media. Summary of the Invention

[0005] To address the above problems, the present invention aims to provide a backwashable high-efficiency filtration device for desalination preparation, which solves the problem of small airflow influence range during the backwashing aeration process.

[0006] The technical solution of the present invention is as follows: a backwashable high-efficiency filtration device for desalination preparation, comprising a barrel body, a partition plate provided on the lower section of the inner wall of the barrel body, an upward protrusion provided at the center of the partition plate, a plurality of filter caps arranged in a ring array around the protrusion on the surface of the partition plate, the partition plate forming a storage platform for holding the medium inside the barrel body, and an inlet and outlet water outlet respectively provided at the upper and lower ends of the barrel body. The partition is provided with a diversion pipe assembly in the protrusion. The diversion pipe assembly is vertically inserted into the partition. The diversion pipe assembly located on the lower side of the partition is provided with an input pipe extending to the outside of the barrel. The diversion pipe assembly is provided with a number of aeration pipe assemblies evenly arranged along the length direction. The surface of the aeration pipe assembly is provided with a number of staggered air nozzles at intervals along the length direction. The nozzle is covered with a shell, and a ball is provided on the lower section of the inner wall of the shell. Two annular shoulders are provided on the lower side of the nozzle surface near the middle section, and the shoulders are provided with clearance grooves for the ball to pass through.

[0007] Furthermore, the side surface of the tank and the upper and lower end faces are respectively provided with inspection holes, media addition holes and water outlet holes. Each hole is provided with a flange-like structure for sealing or connecting to the pipeline. The upper and lower ends of the tank are connected to the raw water pipeline through the water outlet and the backwash pipeline through the water inlet. The inner wall of the tank is provided with a water distribution plate covering the pipe opening of the raw water pipeline. By setting up dedicated holes such as inspection holes and media addition holes with clear division of functions in the tank and configuring flange structures, reliable sealing connection between the equipment and the pipeline is achieved, as well as convenient maintenance and filter media replenishment. The flange structure simplifies disassembly and assembly and is suitable for switching between continuous production conditions. At the same time, the flow paths of raw water and backwash water are clearly defined.

[0008] Furthermore, the partition divides the interior of the tank into two chambers, one larger than the other. The protrusions on its surface are flat-topped cones. When the medium is introduced into the tank, it accumulates on the surface of the partition in the upper chamber of the tank, forming a sand bed. The partition divides the tank into functional chambers, one larger than the other. The upper chamber is the sand bed support and filtration area, and also accommodates aeration-related structures (diversion pipe groups, aeration pipe groups, etc.), ensuring the thickness of the sand bed to increase the amount of impurities retained, and providing sufficient diffusion space for aeration backwashing. The lower chamber is the collection and flow channel for filtered clean water, ensuring smooth discharge of filtered water.

[0009] Furthermore, the diversion pipe group consists of two spaced-apart annular pipes and a connecting pipe between the annular pipes. There are several connecting pipes, which are evenly spaced along the length of the annular pipes. The diversion pipe group is located at the protruding part of the partition. The diversion pipe group is designed as a ring network structure of double annular pipes + uniform connecting pipes, so as to realize the uniform diversion of high-pressure gas to the aeration pipe group, laying the foundation for uniform aeration of the entire barrel diameter.

[0010] Furthermore, the aeration pipe group is composed of several concentric and interconnected annular pipes with the diversion pipe group as the center. The diameter of the annular pipe is adapted to the inner diameter of the barrel. A gap is left between every two vertically adjacent aeration pipe groups. The aeration pipe group is designed as a concentric interconnected annular pipe, which adapts to the inner diameter of the barrel to achieve aeration without dead angles throughout the barrel diameter.

[0011] Furthermore, the air nozzles are spaced apart on the surface of the annular portion of the aeration tube assembly. Every two adjacent air nozzles are staggered on the upper and lower sides of the annular tube. Each air nozzle is a blind tube connected to the aeration tube assembly, and its end and surface are provided with several holes of staggered sizes. The staggered distribution of the air nozzles enables bidirectional staggered spraying, which, together with the aeration tube assembly, achieves 360° aeration without dead angles, enhancing the agitation of filter sand and the separation of impurities.

[0012] Furthermore, the cover is shaped like a pen cap, with several holes of different sizes distributed alternately on its surface and ends. The inner diameter of the cover is larger than the sum of the diameters of the air nozzle and the shoulder, and there is a gap between the cover and the shoulder. The cover is designed to be pen cap-shaped and fitted over the air nozzle, forming a double layer of protection with the staggered holes to prevent the air nozzle from clogging. The gap between the cover and the shoulder allows the cover to swing irregularly like a pressure cooker valve under the action of airflow, improving the uniformity of aeration. The holes in the cover and the holes in the air nozzle form a secondary flow diversion, softening the airflow to prevent filter sand loss and improving the efficiency of impurity removal.

[0013] Furthermore, the baffle ball is a hemispherical protrusion set on the inner wall of the cover. The height of the baffle ball is greater than the distance between the inner wall of the cover on the same side and the shoulder when the inner wall of the cover on the opposite side abuts the shoulder, so that the cover can always be blocked by the baffle ball during the swinging process and will not bypass the shoulder and fall outward.

[0014] Furthermore, a gap is left between the two shoulders, and the two shoulders are inclined to the opposite side. The inclined surfaces of the two shoulders and the gap portion combine to form a limiting groove to accommodate the movement of the ball, so that when the cover is installed, it needs to first pass the upper shoulder, and then move along the limiting groove before it can pass the next shoulder, thus achieving double insurance for the disassembly and assembly of the cover.

[0015] Furthermore, the width of the relief groove is adapted to the maximum diameter of the ball. Both shoulders are provided with relief grooves, with one groove on the upper shoulder and at least three grooves on the lower shoulder. The relief grooves in the two shoulders are staggered. When the cover swings irregularly, even if the ball passes through one shoulder upwards, it cannot pass through the other shoulder. When the ball enters between the two shoulders in the cover, it will also come out along the relief groove on the lower shoulder in the state of irregular movement.

[0016] The beneficial effects of this invention are as follows: 1. This invention firstly utilizes a double-ring pipe design with uniformly connected pipes in the distribution pipe group to evenly distribute high-pressure gas to each aeration pipe group. Secondly, the aeration pipe group is equipped with multiple layers of concentrically connected ring pipes centered on the distribution pipe group, with diameters adapted to the inner diameter of the tank, achieving horizontal coverage of the entire tank diameter, while leaving gaps in the vertical direction to form a three-dimensional aeration area. Finally, the gaps between the cover and the shoulder allow for irregular oscillation similar to a pressure cooker valve under the action of airflow, causing the airflow direction to dynamically change. The synergistic effect of the above structures achieves 360° three-dimensional aeration without dead angles across the entire tank diameter, thoroughly breaking up areas of filter sand compaction, fully stripping impurities from deep filter media, significantly improving backwashing thoroughness compared to existing equipment, and significantly increasing filter media regeneration efficiency. This ensures a continuous and stable filtration process, avoiding filtration efficiency decline and effluent water quality fluctuations caused by filter media clogging.

[0017] 2. In one aspect, the cover, shaped like a pen cap, is fitted over the air nozzle. The staggered holes on its surface and ends form a double-layered protective barrier, directly preventing filter sand and impurities from contacting the air nozzle openings, thus preventing clogging at the source. Simultaneously, the irregular swaying of the cover automatically cleans fine impurities adhering to the openings, achieving self-cleaning. In another aspect, a hemispherical baffle ball is embedded in an inclined limiting groove formed by two shoulders, with the baffle ball's height precisely matching the gap size, restricting the cover's vertical movement. Combined with staggered clearance grooves, this provides a channel for cover assembly and disassembly while ensuring that the baffle ball cannot simultaneously pass through both clearance grooves during operation, preventing the high-pressure airflow from pushing the cover off. This structure ensures the aeration system remains stable under high-pressure backwashing conditions, significantly reducing air nozzle clogging, minimizing component wear, greatly extending the overall service life of the equipment, and reducing the frequency of maintenance failures. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0019] Figure 2 This is a schematic diagram of the shunt tube assembly structure of the present invention.

[0020] Figure 3 This is a schematic diagram of the air nozzle structure of the present invention.

[0021] Figure 4 This is a cross-sectional schematic diagram of the air nozzle structure of the present invention.

[0022] Figure 5 This is a schematic diagram of the shoulder structure of the present invention.

[0023] Attached reference numerals: 1. Tank body; 2. Baffle plate; 3. Filter cap; 4. Diversion pipe assembly; 5. Aeration pipe assembly; 6. Air nozzle; 7. Cover; 8. Baffle ball; 9. Shoulder; 10. Clearance groove. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] like Figure 1-5 As shown, a backwashable high-efficiency filtration device for desalination preparation includes a barrel 1. The side surface and upper and lower end faces of the barrel 1 are respectively provided with inspection holes, media addition holes, and water outlet holes. Each hole has a flange-like structure for sealing or connecting to a pipeline. The upper and lower ends of the barrel 1 are connected to the raw water pipeline through the water outlet and the backwash pipeline through the water inlet. The inner wall of the barrel 1 is provided with a water distribution plate covering the raw water pipeline inlet. By setting clearly defined inspection holes, media addition holes, and other dedicated openings in the barrel 1 and configuring flange structures, reliable sealing and connection between the equipment and the pipeline are achieved, along with convenient maintenance and filter media replenishment. The flange structure simplifies disassembly and assembly, adapting to continuous production switching conditions; simultaneously, the flow paths of raw water and backwash water are clearly defined. The lower section of the inner wall of the tank 1 is provided with a partition 2. The center of the partition 2 has an upward protrusion. The partition 2 divides the inside of the tank 1 into two chambers, one larger than the other. The protrusion on its surface is a flat-topped cone. When the medium is put into the tank 1, it accumulates on the surface of the partition 2 in the upper chamber of the tank 1 to form a sand bed. The partition 2 divides the tank 1 into functional chambers, one larger than the other. The upper chamber is the sand bed bearing and filtration working area, and also accommodates aeration-related structures to ensure the thickness of the sand bed to improve the impurity interception rate and provide sufficient diffusion space for aeration backwashing. The lower chamber is the collection and flow channel for filtered clean water to ensure smooth discharge of filtered water. Several filter caps 3 are arranged in a ring array around the protrusion on the surface of the partition 2. The partition 2 forms a storage platform for holding the medium inside the tank 1. The upper and lower ends of the tank 1 are respectively provided with inlet and outlet water ports. A diversion pipe assembly 4 is provided inside the protrusion of the partition 2. The diversion pipe assembly 4 is vertically inserted into the partition 2. The diversion pipe assembly 4 located on the lower side of the partition 2 has an input pipe extending to the outside of the barrel 1. The diversion pipe assembly 4 is evenly provided with several aeration pipe assemblies 5 along its length. The diversion pipe assembly 4 consists of two spaced annular pipes and a connecting pipe between the annular pipes. There are several connecting pipes, which are evenly spaced along the length of the annular pipes. The diversion pipe assembly 4 is located at the protrusion of the partition 2. Group 4 is designed as a ring network structure of double ring pipes + uniform connecting pipes, which realizes the uniform distribution of high pressure gas to aeration pipe group 5, laying the foundation for uniform aeration throughout the entire barrel diameter. Aeration pipe group 5 is composed of several concentric and interconnected ring pipes with the distribution pipe group 4 as the center. The diameter of the ring pipes is adapted to the inner diameter of the barrel 1. A gap is left between every two vertically adjacent aeration pipe groups 5. The aeration pipe group 5 is designed as a concentric connected ring pipe, which adapts to the inner diameter of the barrel 1 to achieve aeration without dead angles throughout the entire barrel diameter. The surface of the aeration tube assembly 5 is provided with several staggered air nozzles 6 along the length direction. The air nozzles 6 are distributed at intervals on the annular part of the surface of the aeration tube assembly 5. Every two adjacent air nozzles 6 are staggered on the upper and lower sides of the annular tube. Each air nozzle 6 is a blind tube that connects to the aeration tube assembly 5. Several holes of different sizes are opened at the end and on the surface. The staggered distribution of the air nozzles 6 realizes bidirectional staggered spraying, which, together with the aeration tube assembly 5, achieves 360° aeration without dead angles, and enhances the effect of filter sand disturbance and impurity separation. A cover 7 is fitted over the air nozzle 6. The cover 7 is shaped like a pen cap, with several holes of different sizes distributed alternately on its surface and ends. The inner diameter of the cover 7 is larger than the sum of the diameters of the air nozzle 6 and the shoulder 9, and a gap is left between the cover 7 and the shoulder 9. The design of the cover 7 as a pen cap fitted over the air nozzle 6, together with the staggered holes, forms a double layer of protection to prevent the air nozzle 6 from becoming clogged. The gap between the cover 7 and the shoulder 9 allows the cover 7 to oscillate irregularly under the action of airflow, similar to the valve of a pressure cooker, improving the uniformity of aeration. The holes in the cover 7 and the holes in the air nozzle 6 form a secondary flow diversion, softening the airflow to prevent filter sand loss and improving the efficiency of impurity removal. A baffle ball 8 is provided on the lower section of the inner wall of the cover 7, and the surface of the air nozzle 6 is close to the middle The lower side of the section is provided with two annular shoulders 9, with a gap between the two shoulders 9. The two shoulders 9 are inclined to the opposite side. The inclined surfaces of the two shoulders 9 and the gap portion combine to form a limiting groove to accommodate the movement of the blocking ball 8. This means that when the cover 7 is installed, it must first pass over the upper shoulder 9. After the ball moves along the limiting groove, it can pass over the next shoulder 9. This provides double protection for the disassembly and assembly of the cover 7. The blocking ball 8 is a hemispherical protrusion set on the inner wall of the cover 7. The height of the blocking ball 8 is greater than the gap between the inner wall of the cover 7 on the same side and the shoulder 9 when the inner wall of the cover 7 on the opposite side abuts against the shoulder 9. This ensures that the cover 7 is always blocked by the blocking ball 8 during the swinging process and will not pass over the shoulder 9 and fall outward. The shoulder 9 has a clearance groove 10 for the ball 8 to pass through. The width of the clearance groove 10 is adapted to the maximum diameter of the ball 8. Both shoulders 9 have clearance grooves 10. The upper shoulder 9 has one clearance groove, and the lower shoulder 9 has at least three clearance grooves. The clearance grooves 10 in the two shoulders 9 are staggered. When the cover 7 swings irregularly, even if the ball 8 passes through one shoulder 9 upwards, it cannot pass through the other shoulder 9. Furthermore, when the ball 8 in the cover 7 enters between the two shoulders 9, it will also come out along the clearance groove 10 of the lower shoulder 9 in the state of irregular movement.

[0026] Working principle of this invention: I. Normal Filtration Conditions The raw water to be filtered enters through the upper pipe of the tank 1, and after being evenly distributed by the water distribution plate on the inner wall of the tank 1, it permeates from top to bottom into the sand bed in the upper chamber of the partition 2. The impurities in the raw water are intercepted by the sand bed to achieve purification. The filtered clean water passes through the filter cap 3 on the surface of the partition 2 and collects in the lower chamber of the tank 1. Finally, it is discharged from the water outlet at the lower end of the tank 1. Under this condition, the aeration system stops, and the cover 7 remains stable under the limiting action of the baffle ball 8 and the baffle shoulder 9 to prevent filter sand from entering the air nozzle 6 and causing blockage.

[0027] Aeration backwashing conditions Backwash water enters from the inlet at the bottom of the tank 1 and flows upward through the filter cap 3 to impact the sand bed in the opposite direction, causing the filter sand to be in a suspended fluidized state and initially flushing up surface impurities; external high-pressure air source enters through the input pipe of the diversion pipe group 4 and is evenly distributed to the aeration pipe group 5 after being distributed by the diversion pipe group 4. High-pressure airflow is ejected from the nozzle 6 on the surface of the aeration tube group 5, creating a pressure difference between the nozzle 6 and the cover 7, which pushes the cover 7 to swing irregularly around the nozzle 6 as the axis, similar to the valve of a pressure cooker. After the airflow is diverted twice through the openings of the nozzle 6 and the cover 7, it is sprayed into the sand bed at multiple angles to achieve aeration disturbance without dead angles throughout the entire barrel diameter. The aeration airflow and backwash water flow work together to completely remove impurities from the filter sand. The impurities are discharged from the drain port at the top of the tank 1 with the backwash water flow. After backwashing is completed, the water flow and air source are turned off, the filter sand settles by gravity to restore the flat sand bed, and the equipment switches back to normal filtration conditions.

[0028] During the backwashing process, the cover 7, under the limiting cooperation of the ball stop 8, the shoulder stop 9, and the clearance groove 10, only swings slightly and does not come off the air nozzle 6. At the same time, the cover 7 forms a double layer of protection, preventing filter sand from entering the air nozzle 6, ensuring the smooth flow of the aeration system and improving the backwashing efficiency.

[0029] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A backwashable high efficiency filtration device for desalinated water production comprising a tank (1), characterized in that: The lower section of the inner wall of the barrel body (1) is provided with a partition plate (2), the center of the partition plate (2) is provided with an upward protruding part, and a plurality of water filter caps (3) are arranged in an annular array around the protruding part on the surface of the partition plate (2); the partition plate (2) and the barrel body (1) form a storage platform for storing medium; the barrel body (1) is provided with a water outlet and a water inlet at the upper and lower ends, respectively. The protruding part of the partition plate (2) is provided with a shunt pipe group (4), the shunt pipe group (4) is vertically inserted into the partition plate (2), and the shunt pipe group (4) located at the lower side of the partition plate (2) is provided with an input pipe extending to the outside of the barrel body (1); the shunt pipe group (4) is uniformly provided with a plurality of aeration pipe groups (5) along the length direction; the surface of the aeration pipe group (5) is provided with a plurality of staggered air nozzles (6) along the length direction. The air nozzle (6) is provided with a cover shell (7), the lower section of the inner wall of the cover shell (7) is provided with a ball stop (8), the surface of the air nozzle (6) is provided with two annular stop shoulders (9) on the lower side near the middle section, and the stop shoulder (9) is provided with a gap (10) for the ball stop (8) to pass through.

2. The backwashable high efficiency filter apparatus for desalinated water production according to claim 1, characterized in that: The side surface and the upper and lower end surfaces of the barrel body (1) are respectively provided with an inspection hole, a medium adding hole and a water outlet hole; each hole is provided with a flange-shaped structure for closing or communicating with a pipeline; the upper and lower ends of the barrel body (1) are respectively connected to a raw water pipeline through a water outlet and to a backwashing pipeline through a water inlet; and the inner wall of the barrel body (1) is provided with a water distribution disc covering the raw water pipeline opening.

3. The backwashable high efficiency filter apparatus for desalinated water production according to claim 1, characterized in that: The partition plate (2) divides the barrel body (1) into two chambers with the upper chamber being larger than the lower chamber; the protruding part on the surface of the partition plate (2) is in the shape of a flat-topped cone; when the medium is poured into the barrel body (1), the medium accumulates on the surface of the partition plate (2) in the upper chamber of the barrel body (1) to form a sand bed.

4. The backwashable high efficiency filter apparatus for desalinated water production of claim 1, wherein: The shunt pipe group (4) is composed of two annular pipes arranged at intervals and a connecting pipe arranged between the annular pipes; the connecting pipe has a plurality of connecting pipes arranged at intervals along the length direction of the annular pipe; and the shunt pipe group (4) is arranged at the protruding part of the partition plate (2).

5. A backwashable high efficiency filter apparatus for producing desalinated water according to claim 1, characterized in that: The aeration pipe group (5) is composed of a plurality of concentric annular pipes connected to each other and taking the shunt pipe group (4) as the center; the diameter of the annular pipe is adapted to the inner diameter of the barrel body (1); and a gap is left between every two adjacent aeration pipe groups (5) in the vertical direction.

6. A backwashable high efficiency filter apparatus for producing desalinated water according to claim 5, characterized in that: The air nozzles (6) are arranged at intervals on the surface of the annular part of the aeration pipe group (5); every two adjacent air nozzles (6) are arranged at intervals on the upper and lower sides of the annular pipe; each air nozzle (6) is a blind pipe connected to the aeration pipe group (5); and a plurality of holes of different sizes are arranged at intervals on the end and the surface.

7. A backwashable high efficiency filter apparatus for producing desalinated water according to claim 1, characterized in that: The cover shell (7) is in the shape of a pen cap; a plurality of holes of different sizes are arranged at intervals on the surface and the end of the cover shell (7); the inner diameter of the cover shell (7) is greater than the sum of the diameters of the air nozzle (6) and the stop shoulder (9); and a gap is left between the cover shell (7) and the stop shoulder (9).

8. A backwashable high efficiency filter apparatus for producing desalinated water according to claim 1, characterized in that: The ball stop (8) is a semispherical protrusion arranged on the inner wall of the cover shell (7); the height of the ball stop (8) is greater than the distance between the inner wall of the cover shell (7) on the same side and the stop shoulder (9) on the opposite side when the stop shoulder (9) abuts against the inner wall of the cover shell (7).

9. A backwashable high efficiency filter apparatus for producing desalinated water according to claim 1, characterized in that: A gap is left between the two stop shoulders (9); and the opposite sides of the two stop shoulders (9) are arranged at an angle; the inclined surfaces of the two stop shoulders (9) and the gap part are combined to form a limiting groove for accommodating the movement of the ball stop (8).

10. A backwashable high efficiency filter apparatus for producing desalinated water as claimed in claim 1, wherein: The width of the slot (10) is adapted to the maximum diameter of the ball stop (8), each of the two shoulders (9) is provided with a slot (10), the upper shoulder (9) is provided with one slot (10), and the lower shoulder (9) is provided with at least three slots (10), and the slots (10) in the two shoulders (9) are staggered.

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