Filter backwashing system

Abstract

The invention discloses a filter backwashing system, relates to the technical field of filter backwashing, and aims to solve the technical problems that metal fatigue is accelerated by thermal stress circulation and crystals are difficult to wash and clean. The anti-thermal-stress pipe is of a composite structure, thermal stress generated by temperature shock is effectively relieved through cooperation of the low-expansion inner layer, the shape memory middle layer and the high-expansion outer layer, the service life of equipment is prolonged, the air suction outer sleeve forms air-liquid mixed flow according to the Venturi principle, impact force generated by bubble breakage can strengthen crystal removal, and the service life of the equipment is prolonged. The deformation flow channel mechanism achieves two-section type washing, impurities easy to wash are removed in a large-flow mode in the initial stage, gas-liquid mixing needles are used for stubborn crystals in the later stage, pulse flow is generated through cooperation of a pulse pressing sleeve and a pressing piece, and the cleaning effect is enhanced through instantaneous high-pressure shock waves. In addition, a corrugated pipe head adapts to thermal expansion and cold contraction, and the washing distance can be shortened through the multi-section sleeve design of a back-flushing spraying cover; and the recoil performance is optimized, and stable operation of the system under complex working conditions is ensured.

Description

Technical Field

[0001] This invention relates to the field of filter backwashing technology, and more specifically, to a filter backwashing system. Background Technology

[0002] In the chemical manufacturing field, filters are key equipment for ensuring the continuity of production processes and product quality, and the performance of their backwashing systems directly affects production efficiency and equipment lifespan. However, existing filter backwashing technologies have revealed significant shortcomings when dealing with complex chemical conditions, making it difficult to meet the industry's demands for efficient and stable operation. In chemical, pharmaceutical, and fine chemical production processes, filters need to intercept various high-viscosity, highly corrosive, or easily crystallizing chemical media. When the filter element becomes clogged, traditional backwashing systems remove the blockage by backwashing with cleaning fluid to reduce the frequency of filter cleaning. However, this technology faces two major challenges in practical applications: First, the temperature of the media in chemical manufacturing processes is usually at high temperatures (above 200°C) or low temperatures (as low as -50°C), while the temperature of the cleaning fluid used for backwashing often differs significantly from the temperature of the media. During backwashing, the rapid temperature changes generate significant thermal stress on the surface of the filter's metal components (such as filter elements and backwashing pipelines). Repeated thermal stress cycles accelerate metal fatigue, leading to component failures such as cracks and corrosion. For example, in the material filtration stage after high-temperature polymerization, backwashing with room-temperature cleaning fluid can cause thermal shock to the filter element surface, shortening equipment lifespan and increasing maintenance costs. Secondly, crystals produced during chemical manufacturing (such as salts and polymer crystals) have extremely strong adhesive properties, easily forming a dense and hard scale layer on the filter element surface. Traditional backwashing systems rely solely on the flow of cleaning fluid, which is insufficient to effectively remove such stubborn crystals. Therefore, we propose a filter backwashing system. Summary of the Invention

[0003] The purpose of this invention is to provide a filter backwashing system to solve the technical problems of accelerated metal fatigue due to thermal stress cycles and the difficulty in flushing and cleaning crystals.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a filter backwashing system, comprising a backwashing pipe body connected to the inlet and outlet of an external filter, the backwashing pipe body being composed of a heat-reflecting stress pipe and a corrugated pipe head at the end of the heat-reflecting stress pipe, the corrugated pipe head being wavy in shape, a water pump being installed at the end of the corrugated pipe head, a backwash spray hood being installed near the input end of the filter, the backwash spray hood being equipped with multiple mesh nozzles, the heat-reflecting stress pipe comprising an inner tube, a middle tube, and an outer tube, the inner tube being made of a material with a low coefficient of expansion, the middle tube being made of a material that can deform under heat, the outer tube being made of a material with a high coefficient of expansion, an air-suction jacket being installed at one end of the inner tube, the diameter of the middle region of the air-suction jacket being smaller than that of the two end regions, an air-suction pipe being connected to the air-suction jacket, the air-suction pipe passing through the heat-reflecting stress pipe and being equipped with a valve.

[0005] Preferably, the inner tube is made of Invar steel, the middle tube is made of shape memory polymer, and the outer tube is made of aluminum alloy.

[0006] Preferably, the backflush nozzle includes multiple sleeves, which are sequentially connected by mutual limiting sliding tenons. The side walls of the multiple sleeves are provided with backflush outlets. The bottommost sleeve is connected to the corrugated pipe head, and the topmost sleeve is equipped with a nozzle.

[0007] Preferably, the air intake jacket is an arc-shaped structure with a central concave shape. The air intake jacket consists of two expanded neck ends and a central concave arc-shaped neck section. The edge of the expanded neck end is connected to the inner wall of the inner tube by a connecting rod.

[0008] Preferably, a deformable flow channel mechanism is provided on the outer periphery of the concave arc neck section. The deformable flow channel mechanism includes an inner ring body and an outer ring body. The diameter of the outer ring body is larger than that of the inner ring body. The outer ring body is fixed to the inner tube. Multiple connecting plates are installed between the outer ring body and the inner ring body. The multiple connecting plates are arranged in a ring array with the inner ring body as the center. A flow gap is provided between the multiple connecting plates.

[0009] Preferably, the deformable flow channel mechanism further includes a vane plate, which corresponds to the flow gap, the sidewall of which is attached to the connecting plate, the vane plate slides and limits the inner tube, a rotating vane is installed on one side of the vane plate, the end of which is away from the inner ring body is fixed to the inner tube and the suction jacket, the plurality of rotating vanes are inclined, and the rotating vanes are made of a material that deforms under heat.

[0010] Preferably, a pulse pressure sleeve is connected to the inner circumference of the backflush nozzle at the position of the mesh nozzle. The pulse pressure sleeve includes a pulse sleeve and a fixing ring. The fixing ring is a rigid ring shape, and the top of the fixing ring is fixed to the backflush nozzle. The pulse sleeve is made of an elastically deformable material.

[0011] Preferably, the pulse sleeve has a diameter that gradually increases from the center to both ends, and the pulse sleeve consists of a pressure section and a positioning end.

[0012] Preferably, a pulse pressure member is provided between the outer peripheries of the plurality of pressure-bearing sections, the pulse pressure member comprising a plurality of undulating pressure sleeves, the undulating pressure sleeves being located on and in contact with the outer periphery of the pressure-bearing sections.

[0013] Preferably, the pulse pressure component further includes multiple crossbars, and connecting bends are connected between the crossbars and the corresponding multiple fluctuating pressure sleeves. One end of the connecting bend is connected to an elastic rod, which is made of elastic metal. One end of the elastic rod is connected to a rigid connecting rod between it and the bellows head.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes a composite structure of "low-expansion inner layer + shape memory intermediate layer + high-expansion outer layer" in the anti-thermal stress pipe. It leverages the stability of the Invar inner layer, the high expansion characteristics of the aluminum alloy outer layer, and the temperature deformation capability of the shape memory polymer intermediate layer. When the temperature rises, the outer layer expands preferentially, and the intermediate layer absorbs thermal stress through elastic deformation. When the temperature drops, it assists the outer layer in shrinking and restoring. This design effectively alleviates the thermal stress caused by sudden temperature changes during backwashing, avoids fatigue failure problems such as cracks and corrosion in metal components due to repeated thermal stress cycles, extends the service life of filters and backwash pipelines, reduces equipment maintenance costs in chemical production, and solves the problem of accelerated metal fatigue caused by thermal stress cycles.

[0015] 2. This invention also utilizes the Venturi principle through the suction jacket to create a localized low-pressure zone as the backwash liquid flows through the concave arc neck section. External gas is then drawn in through the suction pipe, forming a gas-liquid mixture. When this gas-liquid mixture is ejected at high speed from the mesh nozzle of the backwash spray hood, the localized impact force generated by the bursting of microbubbles effectively weakens the mechanical strength of the crystals on the filter element surface. Combined with the flushing action of the liquid, this significantly improves the removal effect on highly adhesive crystals (such as salts and polymer crystals). Compared to traditional methods that rely solely on liquid flushing, this design can more thoroughly remove stubborn scale layers, restore the filter element's filtration performance, and further solve the problem of difficult-to-flushing and cleaning of crystals.

[0016] 3. This invention also achieves staged backwashing through the cooperation of rotating vanes and rotating transfer vanes. In the initial stage of backwashing, the flow gap allows a large flow of liquid to directly flush and quickly remove easily rinseable impurities. As the temperature rises or the washing process progresses, the heated rotating transfer vanes drive the rotating vane plate to block the flow gap, forcing the liquid to flow through the suction jacket to form a gas-liquid mixture, which intensifies the washing of stubborn crystals. This two-stage design not only improves the initial washing efficiency but also specifically solves the problem of crystal removal, optimizing the washing process and reducing the consumption of cleaning fluid while ensuring the backwashing effect.

[0017] 4. This invention also generates periodic fluctuations during backwashing through the combination of a pulse pressure sleeve and a pulse pressure element. The cooperation of the elastic rod and the rigid connecting rod causes the oscillating pressure sleeve to move up and down in the pressure section, squeezing the pulse sleeve to change the internal flow velocity and forming a pulse flow. The instantaneous high-pressure shock wave can break through the adhesion force of crystals and perform a "brushing" cleaning on the filter element surface. It is especially suitable for removing dense and hard scale layers. Compared with traditional DC flushing, the dynamic impact of the pulse flow can more effectively break down the crystal structure, improve the backwashing's ability to remove stubborn impurities under complex chemical conditions, and ensure that the filter maintains high filtration efficiency for a long time.

[0018] 5. The present invention also utilizes the corrugated structure of the corrugated pipe head to adapt to the displacement of the backwash tube during thermal expansion and contraction, avoiding additional stress caused by deformation of the pipeline. The multi-section sliding tenon design of the backwash spray hood allows the hood to move closer to the filter element under the impact of the backwash liquid, shortening the rinsing distance and enhancing the local rinsing intensity. After backwashing, the pull-back force of the elastic rod drives the spray hood to reset, avoiding long-term impact during normal filtration. This structural design not only ensures efficient cleaning during the backwashing process, but also protects the mechanical properties of the backwash spray hood through adaptive adjustment, improving the operational stability of the system under complex working conditions. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of the flushing pipe connected to the filter input end in the backwashing state in this invention; Figure 3 This is a schematic diagram of the flushing pipe body in this invention; Figure 4 This is a schematic diagram of the installation structure of the suction jacket in this invention; Figure 5 This is a schematic diagram of the connection structure between the air-absorbing jacket and the deformable flow channel mechanism in this invention; Figure 6 In this invention Figure 4 Enlarged view of the structure at point A; Figure 7 This is a schematic diagram of the structure of the air-absorbing jacket in this invention; Figure 8 This is a schematic diagram of the connection structure between the inner and outer ring bodies in this invention; Figure 9 This is a schematic diagram of the connection structure between the rotary plate and the rotary shift plate in this invention; Figure 10 This is a schematic diagram of the internal structure of the backwash spray hood in the backwashing state of the present invention; Figure 11 In this invention Figure 10 Enlarged view of the structure at point B; Figure 12 This is a schematic diagram of the cross-sectional structure of the pulse pressure sleeve in this invention; Figure 13 This is a schematic diagram of the bending and storage structure of the elastic rod in the non-backwashing state of the present invention.

[0020] Explanation of the labels in the diagram: 1. Flushing pipe body; 101. Reverse thermal stress pipe; 1011. Inner layer pipe; 1012. Intermediate pipe; 1013. Outer layer pipe; 102. Corrugated pipe head; 2. Water pump; 3. Backflush spray hood; 301. Sleeve; 302. Hood head; 4. Suction jacket; 401. Expanded neck end; 402. Concave arc neck section; 5. Suction pipe; 6. Connecting rod; 7. Deformation flow channel mechanism; 8. Pulse pressure sleeve; 9. Pulse pressure component; 701 Inner ring body; 702 Outer ring body; 703 Connecting plate; 704 Flow gap; 705 Rotating vane plate; 706 Rotating vane; 801 Pulse sleeve; 8011 Pressure section; 8012 Positioning end; 802 Fixed ring; 901 Fluctuating pressure sleeve; 902 Crossbar; 903 Connecting bent rod; 904 Elastic rod; 905 Rigid connecting rod. Detailed Implementation

[0021] like Figures 1 to 13 As shown, the present invention relates to a filter backwashing system, comprising a backwashing pipe 1 connected to the inlet and outlet of an external filter. The backwashing pipe 1 consists of a backheat stress pipe 101 and a corrugated pipe head 102 at the end of the backheat stress pipe 101. The corrugated pipe head 102 is wavy in shape. A water pump 2 is installed at the end of the corrugated pipe head 102. A backwash spray hood 3 is installed near the filter inlet end of the corrugated pipe head 102. Multiple mesh nozzles are installed on the backwash spray hood 3. The backheat stress pipe 101 includes an inner... The tube consists of an inner tube 1011, an intermediate tube 1012, and an outer tube 1013. The inner tube 1011 is made of a material with a low coefficient of expansion, preferably Invar. The intermediate tube 1012 is made of a material that can be deformed by heat, preferably made of shape memory polymer. The outer tube 1013 is made of a material with a high coefficient of expansion, preferably made of aluminum alloy. The corrugated head 102 has a wave-like shape that can adapt to movement during thermal expansion and contraction.

[0022] Working principle: When the temperature of the backwash medium rises, the outer tube 1013 will expand preferentially due to its higher coefficient of thermal expansion. Due to the presence of the middle tube 1012, it will change shape when it reaches a certain temperature, softening and allowing the outer tube 1013 to expand. At the same time, it absorbs some of the thermal stress through its own elastic deformation. As the temperature rises further, the middle tube 1012 softens completely, and the expansion of the outer tube 1013 pushes it to expand outward. The relative stability of the inner tube 1011 limits excessive expansion, avoiding pipeline damage due to excessive thermal stress.

[0023] When the temperature drops, the outer tube 1013 contracts, and the middle tube 1012 returns to its initial shape, helping to pull the outer tube 1013 back to a certain extent. At the same time, the inner tube 1011 also provides certain constraints for the contraction process, so that the entire composite tube can smoothly return to a state close to its initial state, effectively relieving the thermal stress caused by temperature fluctuations and reducing metal fatigue corrosion.

[0024] To improve the anti-impact effect, taking advantage of the low expansion stability of the inner tube 1011, an air intake jacket 4 is installed at one end of the inner tube 1011. The diameter of the middle region of the air intake jacket 4 is smaller than that of the two end regions. An air intake pipe 5 is connected to the air intake jacket 4. The air intake pipe 5 passes through the anti-thermal stress tube 101 and is equipped with a valve. A pressure sensor can be installed on the side wall of the air intake jacket 4. The opening and closing of the valve is selected by the pressure change of the pressure sensor. The air intake jacket 4 is a centrally concave arc neck structure. The air intake jacket 4 consists of two expanded neck ends 401 and a central concave arc neck section 402. The edge of the expanded neck end 401 is connected to the inner wall of the inner tube 1011 by a connecting rod 6. At this time, the multiple connecting rods 6 are set to be closed.

[0025] Working principle: When backwash liquid is transported, as it flows through the suction jacket 4, the flow velocity increases and the pressure decreases at the concave arc neck section 402. According to the Venturi principle, external gas is drawn into the backwash liquid through the suction pipe 5 under the action of pressure difference, forming a gas-liquid mixture. This design can efficiently mix gas into the backwash liquid. When the gas-liquid mixture enters the backwash spray hood 3, the liquid and gas are ejected at high speed through these tiny nozzles. When the gas is ejected, it forms a large number of tiny bubbles. After being ejected, the bubbles can be evenly dispersed near the filter element surface. The tiny bubbles break when they impact the crystalline scale at high speed. The resulting local impact force can effectively destroy the crystalline structure, remove the crystalline scale, and improve the backwashing effect on removing crystalline impurities.

[0026] It should be noted that, depending on the situation, the amount of mixed gas can be controlled by adjusting the gas source pressure and the size of the air inlet.

[0027] To improve the anti-impact effect, the anti-impact spray hood 3 includes multiple sleeves 301, which are connected to each other in sequence by sliding tenons. The side walls of the multiple sleeves 301 are provided with anti-impact outlets. The bottom sleeve 301 is connected to the corrugated pipe head 102, and the top sleeve 301 is equipped with a hood head 302.

[0028] Working principle: The impact force of the backwash liquid input can push the hood 302 to move upward. With the cooperation of the sliding tenon sleeves of multiple sleeves 301, the hood 302 can move closer to the filter element, shorten the flushing distance, improve the flushing effect, and the design of multiple backwash outlets can clean the inner wall.

[0029] In the early stages of backwashing, there are many easily rinsed impurities. If the suction jacket 4 is used directly, the flow rate will decrease, which will reduce the cleaning effect on easily rinsed impurities. To address this, a two-stage rinsing mode is designed.

[0030] First, there is a flow gap between the connecting rod 6 and the inner wall of the inner tube 1011. Second, a deformable flow channel mechanism 7 is provided on the outer periphery of the concave arc neck section 402. The deformable flow channel mechanism 7 includes an inner ring body 701 and an outer ring body 702. The outer ring body 702 has a larger diameter than the inner ring body 701. The outer ring body 702 is fixed to the inner tube 1011. Multiple connecting plates 703 are installed between the outer ring body 702 and the inner ring body 701. The multiple connecting plates 703 are arranged in a ring array with the inner ring body 701 as the center. A flow gap 704 is provided between the multiple connecting plates 703.

[0031] The deformable flow channel mechanism 7 also includes a vane plate 705, which corresponds to the flow gap 704. The vane plate 705 is in contact with the side wall of the connecting plate 703. The vane plate 705 slides and is limited by the inner tube 1011. A rotating vane 706 is installed on one side of the vane plate 705. The end of the rotating vane 706 away from the inner ring body 701 is fixed to the inner tube 1011 and the suction jacket 4. The multiple rotating vanes 706 are inclined and are made of a material that deforms when heated.

[0032] Working principle: Due to the presence of the flow gap 704, when the backwash fluid passes through, it impacts the inclined plate of the rotating vane 706. Combined with the effect of the heated deformation of the rotating vane 706, it can drive the rotating plate 705 to move towards the flow gap 704. During this process, the diameter of the flow channel of the backwash fluid is large, which can maintain a large flow rate of flushing. Easily flushable impurities are flushed out first. After the flow gap 704 is blocked, the backwash fluid can only be input from the suction jacket 4. At this time, the pressure changes, and the valve of the suction pipe 5 is opened, allowing external air to be drawn in, generating gas-liquid mixing and producing high-velocity bubbles.

[0033] Relying solely on direct current rinsing results in a fixed rinsing flow rate, making it difficult to effectively clean crystals. To further improve the rinsing effect on crystals, it is designed to be pulse-type cleaning, as shown in the following structure.

[0034] The inner circumference of the backjet nozzle 3 is connected to the mesh nozzle position with a pulse pressure sleeve 8. The pulse pressure sleeve 8 includes a pulse sleeve 801 and a fixing ring 802. The fixing ring 802 is a rigid ring shape. The top fixing ring 802 is fixed to the backjet nozzle 3. The pulse sleeve 801 is made of an elastically deformable material.

[0035] The pulse sleeve 801 has a diameter that gradually increases from the center to both ends. The pulse sleeve 801 consists of a pressure section 8011 and a positioning end 8012.

[0036] A pulse pressure element 9 is provided between the outer peripheries of multiple pressure sections 8011. The pulse pressure element 9 includes multiple undulating pressure sleeves 901, which are located on the outer periphery of the pressure section 8011 and fit together.

[0037] The pulse pressure component 9 also includes multiple crossbars 902. A connecting bent rod 903 connects the crossbars 902 to the corresponding multiple undulating pressure sleeves 901. One end of the connecting bent rod 903 is connected to an elastic rod 904. The elastic rod 904 is made of elastic metal. The elasticity of the elastic rod 904 is less than the impact force of the backwash liquid. When the backwash liquid impacts, it can push the backwash spray hood 3 to unfold, further straightening the elastic rod 904 and maintaining a pull-back force, which facilitates the folding and resetting of the backwash spray hood 3. The folding of the backwash spray hood 3 is to avoid the backwash spray hood 3 being too close to the filter element during normal filtration and bearing the impact force for a long time, thus reducing its service life. A rigid connecting rod 905 connects one end of the elastic rod 904 to the bellows head 102.

[0038] Working principle: During backwashing, the backwash spray hood 3 is fully deployed. Due to the fit between the pressure section 8011 of the pulse sleeve 801 and the undulating pressure sleeve 901, combined with the flow rate of the backwash fluid, the elasticity of the elastic rod 904, and the connection between the rigid connecting rod 905 and the bellows head 102, fluctuations will occur in the position area. During the fluctuation, the undulating pressure sleeve 901 will move up and down in the pressure section 8011, generating compression and changing the internal flow rate, thus achieving a pulse effect. The pulse flow generates an instantaneous high-pressure shock wave, which breaks through the mechanical strength of the crystal.

[0039] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A filter backwash system characterized by, The utility model provides a filter flushing device, including with the filter inlet and outlet communication's flushing pipe body (1), the flushing pipe body (1) is by anti thermal stress pipe (101) and the bellows head (102) at anti thermal stress pipe (101) end, the bellows head (102) is the undulating shape, the bellows head (102) end is installed with water pump (2), is close to the bellows head (102) of filter input and is installed with backflushing spray cover (3), is installed with a plurality of netted shower nozzles on backflushing spray cover (3); The anti thermal stress pipe (101) comprises an inner tube (1011), an intermediate tube (1012) and an outer tube (1013), the inner tube (1011) is made of a material with low expansion coefficient, the intermediate tube (1012) is made of a material that can be deformed under heat, and the outer tube (1013) is made of a material with high expansion coefficient; One end of the inner tube (1011) is provided with an air suction sleeve (4), the diameter of the middle region of the air suction sleeve (4) is smaller than that of the two end regions, and the air suction sleeve (4) is connected with an air suction pipe (5) therethrough, and the air suction pipe (5) penetrates the anti thermal stress pipe (101) and is provided with a valve.

2. A filter backwash system according to claim 1, wherein, The inner tube (1011) is made of invar steel, the intermediate tube (1012) is made of a shape memory polymer, and the outer tube (1013) is made of an aluminum alloy.

3. A filter backwash system according to claim 1, wherein, The backflushing spray cover (3) comprises a plurality of joint sleeves (301), the plurality of joint sleeves (301) are connected in sequence by limiting and sliding tenon and mortise, the side walls of the plurality of joint sleeves (301) are provided with backflushing outlets, the bottommost joint sleeve (301) is connected with the bellows head (102), and the topmost joint sleeve (301) is provided with a cover head (302).

4. The filter backwash system of claim 1 or 3, wherein, The air suction sleeve (4) is an arc neck structure with a concave center, the air suction sleeve (4) comprises expanded neck ends (401) at both ends and a concave arc neck segment (402) at the center, and the edges of the expanded neck ends (401) are connected with the inner wall of the inner tube (1011) by connecting rods (6).

5. A filter backwash system according to claim 4, wherein, The concave arc neck segment (402) is provided with a deformation flow channel mechanism (7), the deformation flow channel mechanism (7) comprises an inner ring body (701) and an outer ring body (702), the diameter of the outer ring body (702) is greater than that of the inner ring body (701), the outer ring body (702) is fixed with the inner tube (1011), a plurality of connecting plates (703) are arranged between the outer ring body (702) and the inner ring body (701), the plurality of connecting plates (703) are arranged in a ring array with the inner ring body (701) as the center, and flow gaps (704) are arranged between the plurality of connecting plates (703).

6. A filter backwash system according to claim 5, wherein, The variable flow channel mechanism (7) further comprises a rotary vane plate (705) corresponding to the flow communication gap (704), the rotary vane plate (705) is attached to the side wall between the connecting plate (703), the rotary vane plate (705) is limited to slide with the inner layer pipe (1011), one side of the rotary vane plate (705) is provided with a rotary moving vane (706), the rotary moving vane (706) is fixed away from the inner ring body (701) end with the inner layer pipe (1011) and the air suction outer sleeve (4), a plurality of the rotary moving vane (706) is inclined, the rotary moving vane (706) is made of a material capable of being deformed by heat.

7. A filter backwash system according to claim 3 or 6, wherein, The inner wall of the backflush spray cover (3) is connected with pulse pressure sleeve (8) at the position of the mesh spray head, the pulse pressure sleeve (8) comprises pulse sleeve (801) and fixed ring (802), the fixed ring (802) is a hard ring body shape, the top end of the fixed ring (802) is fixed with the backflush spray cover (3), the pulse sleeve (801) is made of a material capable of being elastically deformed.

8. A filter backwash system according to claim 7, wherein, The pulse sleeve (801) is gradually increased in diameter from the center to both ends, the pulse sleeve (801) is composed of a pressure receiving section (8011) and a positioning end (8012).

9. A filter backwash system according to claim 8, wherein, A plurality of the pressure receiving section (8011) is provided with pulse pressure piece (9) between the outer periphery, the pulse pressure piece (9) comprises a plurality of wave pressure sleeve (901), the wave pressure sleeve (901) is located at the outer periphery of the pressure receiving section (8011) and is attached.

10. A filter backwash system according to claim 9, wherein, The pulse pressure piece (9) further comprises a plurality of cross bars (902), the cross bars (902) are connected with a plurality of corresponding wave pressure sleeve (901) between the connecting bent rod (903), one end of the connecting bent rod (903) is connected with elastic rod (904), the elastic rod (904) is a elastic metal material, the elastic rod (904) is connected with hard connecting rod (905) between one end and the bellows head (102).

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