Soilless filtration system for stock solution regeneration and solid-liquid separation regeneration method thereof

Abstract

The present invention discloses a stock solution regeneration soilless filtration system and a solid-liquid separation regeneration method thereof, and relates to the technical field of filtration, the stock solution regeneration soilless filtration system comprises a stock solution tank, a delivery pump, a residual liquid-free filtration cylinder and a purification liquid tank which are sequentially communicated, the residual liquid-free filtration cylinder comprises a cylinder body and a filtration core, the bottom of the cylinder body is provided with a solid discharge port and a liquid inlet pipeline, a liquid outlet pipeline, a cleaning pipeline and a third gas supply pipeline are arranged at the top of the barrel, a solid discharge valve is arranged at the solid discharge port, the top of an inner cavity of the barrel is communicated with the first gas supply pipeline, the bottom of the inner cavity of the barrel is communicated with a residual liquid return pipeline, and the purification liquid tank is communicated with the cleaning pipeline; according to the invention, the first gas supply pipeline is used for original hydraulic return to avoid solid discharge waste, the third gas supply pipeline is used for blowing down and discharging a filter cake, the cleaning pipeline is used for realizing regeneration of the filter element, and the regeneration effect of the filter element is good; when the stock solution is used for backflow cleaning, residues in the barrel are still the stock solution, and subsequent stock solution filtering is not affected at all.

Description

Technical Field

[0001] The present invention relates to the technical field of filtration, and particularly to a soil-free filtration system for raw liquid regeneration and a solid-liquid separation and regeneration method thereof. Background Art

[0002] With the rapid development and application of advanced technologies, the requirements for fluids in both life and industrial production are getting higher and higher. Especially for beverages, currently, filters are often used as the main filtration equipment for beverages in the market. The core component of the filter is the filter element. However, during the use process, the filter element will gradually be blocked by impurities and unable to work continuously. But if the non-functional filter element is discarded and a new one is replaced, it will cause a problem of large consumption of consumables.

[0003] In the prior art, when solving the problem of filter element blockage, the method of backwashing regeneration is often adopted. Specifically, gas or liquid is used as the cleaning fluid, and the cleaning fluid enters from the liquid outlet of the filter element. The flow direction of the cleaning fluid is opposite to that of the filtrate, so as to flush out the impurities blocking the filter element and discharge them from the solid discharge port at the bottom of the filter. However, during the sewage discharge process, the cleaning fluid is discharged together with the raw liquid and impurities in the filter, resulting in waste of the raw liquid. Moreover, when using liquid for sewage discharge, part of the liquid will remain in the filter element, affecting the filtrate for subsequent filtration.

[0004] Therefore, there is an urgent need for a soil-free filtration system for raw liquid regeneration that uses raw liquid for regeneration, has a good regeneration effect, and saves raw liquid resources. Summary of the Invention

[0005] The purpose of the present invention is to provide a soil-free filtration system for raw liquid regeneration and a solid-liquid separation and regeneration method thereof to solve the problems existing in the above prior art. Before sewage discharge, the raw liquid in the cylinder is pumped out by the air supply of the first air supply pipeline, reducing the waste of the raw liquid during the sewage discharge process, and at the same time improving the regeneration effect. During cleaning, the raw liquid is used as the reflux of the cleaning liquid for cleaning, reducing the influence on the filtrate when there is residual cleaning liquid.

[0006] To achieve the above object, the present invention provides the following solution: The present invention provides a soilless filtration system for stock solution regeneration, comprising a stock solution tank, a delivery pump, at least one residue-free filter cartridge, and a purified liquid tank connected in sequence. The residue-free filter cartridge includes a cylinder body and a filter element. The filter element is vertically arranged in the cylinder body. A solid discharge port and a liquid inlet pipeline are provided at the bottom of the cylinder body, and a liquid outlet pipeline, a cleaning pipeline, and a third gas supply pipeline, all connected to the filter element, are provided at the top. A solid discharge valve is arranged at the solid discharge port. The top inner cavity of the cylinder body is connected to a first gas supply pipeline, and the bottom inner cavity of the cylinder body is connected to a residue liquid pressure return pipeline. Valves are provided on the liquid inlet pipeline of the cylinder body, the liquid outlet pipeline of the cylinder body, the cleaning pipeline, the first gas supply pipeline, the residue liquid pressure return pipeline, and the third gas supply pipeline. The purified liquid tank is connected to the cleaning pipeline.

[0007] Preferably, the residue-free filter cartridge is connected to the purified liquid tank through a precision filter.

[0008] Preferably, the purified liquid tank is connected to the cleaning pipeline and the liquid outlet pipeline of the precision filter through a pump body and a filter respectively.

[0009] Preferably, the pipeline between the precision filter and the purified liquid tank is connected to the cleaning pipeline, and valves are provided on the connecting pipeline between the precision filter and the cleaning pipeline and the connecting pipeline between the precision filter and the purified liquid tank.

[0010] Preferably, a discharge pipeline is provided at the bottom of the purified liquid tank, and a purified liquid delivery pump and a valve body are arranged on the discharge pipeline. The purified liquid delivery pump and the valve body of the discharge pipeline are both electrically connected to a control system.

[0011] Preferably, a second gas supply pipeline is connected to the bottom inner cavity of the cylinder body, and a valve is provided on the second gas supply pipeline.

[0012] Preferably, the first gas supply pipeline, the second gas supply pipeline, and the third gas supply pipeline are all connected to a compressed gas supply device through a main gas supply pipeline, and a pressure regulating valve for controlling pressure is provided on the main gas supply pipeline.

[0013] Preferably, a residue liquid discharge pipeline is provided at the top of the cylinder body. The liquid outlet of the residue liquid discharge pipeline is connected to the stock solution tank, and the liquid inlet is located at the bottom inner cavity of the filter element.

[0014] The present invention also provides a solid-liquid separation and regeneration method using the above soilless filtration system for stock solution regeneration, comprising the following steps:

[0015] S1: Stop the liquid inlet of the liquid inlet pipeline, open the residue liquid pressure return pipeline of the pressure return pipeline and the first gas supply pipeline, and the stock solution in the cylinder body is pressed out;

[0016] S2: After the original hydraulic discharge is completed, close the residual hydraulic return pipeline of the pressure return pipeline and the first gas supply pipeline, open the second gas supply pipeline and the exhaust pipeline, and blow and solidify the filter cake.

[0017] S3: After the blowing and solidifying is completed, close the second gas supply pipeline and the exhaust pipeline, open the third gas supply pipeline and the sewage discharge valve (solid discharge valve), and the gas blows from inside the filter element to inside the cylinder body, in the opposite direction to the flow direction of the filtrate, to achieve backwashing. During the backwashing process, the filter cake and the impurities outside the filter element are blown off and discharged from the sewage discharge port (solid discharge port), completing the solid-liquid separation.

[0018] S4: After the filter cake is discharged, close the third gas supply pipeline and the sewage discharge valve (solid discharge valve), open the cleaning pipeline and the residual hydraulic return pipeline of the pressure return pipeline, and use the original liquid to clean the remaining impurities.

[0019] The present invention mainly achieves the following technical effects compared with the prior art:

[0020] The gas supplied through the first gas supply pipeline can press the original liquid in the cylinder body into the residual hydraulic return pipeline to avoid waste of solid discharge. After all the original liquid in the cylinder body is pressed out, open the solid discharge valve and the third gas supply pipeline to blow down and discharge the filter cake. Then, after closing the solid discharge valve, open the cleaning pipeline, which moves from the inside of the filter element to the outside of the filter element to remove the remaining impurities on the filter element, realizing the regeneration of the filter element. When using the original liquid for reflux cleaning, the residue in the cylinder body is still the original liquid, which does not cause any impact on the subsequent filtration of the original liquid. When the original liquid is being cleaned, the solid discharge valve is in the closed state.

[0021] Other solutions of the present invention achieve the following technical effects compared with the prior art:

[0022] The cooperation of the second gas supply pipeline and the exhaust pipeline enables the gas to flow inside the cylinder body, realizing the blowing and solidifying of the filter cake. At this time, the filter cake has reduced viscosity due to lack of moisture. Using the gas from the third gas supply pipeline to blow from the inside to the outside of the filter element can more effectively blow off the filter cake and the impurities inside the filter element, improving the regeneration effect of the filter element, reducing the impurity content in the original liquid during the subsequent original liquid cleaning process, and at the same time, the water content of the debris discharged from the solid discharge port is relatively low, improving the convenience of its cleaning and the convenience of subsequent sludge treatment, meeting the environmental protection requirements.

[0023] The cooperation of the second gas supply pipeline and the residual liquid discharge pipeline can discharge the residual liquid inside the filter element. After shutdown, it can ensure that there is no residual filtrate inside the filter element, avoiding waste of this part of the filtrate. Description of the Drawings

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is the system diagram of the raw liquid regeneration soil-free filtration system in the embodiment of the present invention;

[0026] Among them, 1. Raw liquid tank; 2. Residual liquid-free filter cartridge; 3. Precision filter; 4. Purified liquid tank; 5. Residual liquid discharge pipeline; 6. First air supply pipeline; 7. Third air supply pipeline; 8. Cleaning pipeline; 9. Second air supply pipeline; 10. Solid discharge valve. Specific embodiments

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] The purpose of the present invention is to provide a raw liquid regeneration soil-free filtration system and its solid-liquid separation and regeneration method to solve the problems existing in the prior art. Before sewage discharge, the raw liquid in the cylinder is pressed out by the air supply of the first air supply pipeline, reducing the waste of raw liquid during the sewage discharge process and improving the regeneration effect at the same time. When cleaning, the raw liquid is used as the reflux of the cleaning liquid for cleaning, reducing the impact on the filtered liquid when there is residual cleaning liquid.

[0029] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Please refer to as Figure 1As shown in the figure, a soil-free filtration system for stock solution regeneration is provided, which includes a stock solution tank 1, a delivery pump, at least one residue-free filter cartridge 2, and a purified liquid tank 4 that are connected in sequence. The delivery pump pumps the stock solution in the stock solution tank 1 into the residue-free filter cartridge 2 for filtration and then stores it in the purified liquid tank 4. The residue-free filter cartridge 2 includes a cylinder body and a filter element. The filter element is vertically arranged in the cylinder body through an internal partition in the cylinder body. In order to improve the filtration effect, multiple filter elements are arranged in the cylinder body. The bottom of the cylinder body is provided with a solid discharge port and a liquid inlet pipeline, and the top is provided with a liquid outlet pipeline, a cleaning pipeline 8, and a third air supply pipeline 7. The liquid outlet pipeline, the cleaning pipeline 8, and the third air supply pipeline 7 are all connected to the inner cavity of the filter element. A solid discharge valve 10 is arranged at the solid discharge port. The top of the inner cavity of the cylinder body is connected to the first air supply pipeline 6, and the bottom of the inner cavity of the cylinder body is connected to a residue liquid return pipeline. Valves are arranged on the liquid inlet pipeline, the liquid outlet pipeline, the cleaning pipeline 8, the first air supply pipeline 6, the third air supply pipeline 7, and the residue liquid return pipeline. The purified liquid tank 4 is connected to the cleaning pipeline 8. The power source for supplying the cleaning liquid in the cleaning pipeline 8 is the delivery pump. The working principle of this system is as follows: The gas supplied through the first air supply pipeline 6 can press the stock solution in the cylinder body into the residue liquid return pipeline to avoid waste of solid discharge. After all the stock solution in the cylinder body is pressed out, the solid discharge valve 10 and the third air supply pipeline 7 are opened to blow down and discharge the filter cake. Then, after closing the solid discharge valve 10, the cleaning pipeline 8 is opened, and the cleaning liquid moves from the inside of the filter element to the outside of the filter element to remove the remaining impurities on the filter element, realizing the regeneration of the filter element. When using the stock solution for backwashing, the residue in the cylinder body is still the stock solution, which does not cause any impact on the subsequent filtration of the stock solution. When backwashing with the stock solution, the solid discharge valve 10 is in the closed state.

[0031] In order to improve the filtration effect on the stock solution, the residue-free filter cartridge 2 is connected to the purified liquid tank 4 through a precision filter 3, which is equivalent to filtering the stock solution in a secondary filtration manner.

[0032] The purified liquid tank 4 is connected to the cleaning pipeline 8 and the liquid outlet pipeline of the precision filter 3 through a pump body and a filter respectively. The setting of the pump body and the filter enables the overall system to complete a major cleaning regularly, that is, using the pump body and the filter to pump the filtered liquid in the purified liquid tank 4 to the precision filter 3 and the residue-free filter cartridge 2 to synchronously perform reverse flushing on the filter elements of both.

[0033] The pipeline between the precision filter 3 and the purified liquid tank 4 is connected to the cleaning pipeline 8. Valves are arranged on the connecting pipeline between the precision filter 3 and the cleaning pipeline 8 and the connecting pipeline between the precision filter 3 and the purified liquid tank 4, and the opening and closing of the relevant pipelines can be controlled by controlling the opening and closing of the valves.

[0034] A discharge pipeline is arranged at the bottom of the purified liquid tank 4, and a purified liquid delivery pump and a valve body are arranged on the discharge pipeline. The purified liquid delivery pump and the valve body of the discharge pipeline are both electrically connected to the control system.

[0035] A second gas supply pipeline 9 is connected to the bottom of the inner cavity of the cylinder body. A valve is provided on the second gas supply pipeline 9. The cooperation of the second gas supply pipeline 9 and the exhaust pipeline realizes the circulation of gas in the cylinder body. The exhaust pipeline can be directly arranged on the cylinder body to blow and solidify the filter cake. At this time, due to the lack of moisture, the viscosity of the filter cake decreases. The gas from the third gas supply pipeline 7 is blown from the inside to the outside of the filter element, which more effectively blows off the filter cake and the impurities in the filter element, improves the regeneration effect of the filter element, reduces the impurity content in the original liquid during the subsequent original liquid cleaning process, and at the same time, the water content of the sundries discharged from the solid discharge port is low, improving the convenience of its cleaning and the convenience of subsequent sludge treatment, meeting the environmental protection requirements.

[0036] The first gas supply pipeline 6, the second gas supply pipeline 9, and the third gas supply pipeline 7 are all connected to the compressed gas supply equipment through the main gas supply pipeline. A pressure regulating valve for controlling the pressure is provided on the main gas supply pipeline.

[0037] The main gas supply pipeline is provided with a branch communicating with the liquid outlet end of the precision filter 3. The precision filter 3 can be regenerated by backwashing. A valve is provided on the branch.

[0038] A filter can be provided at the air inlet of the main gas supply pipeline to improve the cleanliness of the gas.

[0039] A gas storage tank is provided between the main gas supply pipeline and the compressed gas supply equipment to play a buffering role.

[0040] A residual liquid discharge pipeline 5 is provided at the top of the cylinder body. The liquid outlet of the residual liquid discharge pipeline 5 is connected to the original liquid tank 1, and the liquid inlet is located at the bottom of the inner cavity of the filter element. The cooperation of the second gas supply pipeline 9 and the residual liquid discharge pipeline 5 can use the pressure to discharge the residual liquid in the filter element through the residual liquid discharge pipeline 5. After shutdown, it can ensure that there is no residual filter liquid in the filter element, avoiding the waste of this part of the filter liquid.

[0041] The residual liquid backpressure pipeline is connected to the original liquid tank 1. The pressed-back original liquid enters the original liquid tank 1 for storage. At the same time, in order to improve the pressed-back effect of the original liquid, the liquid inlet of the residual liquid backpressure pipeline should be arranged close to the bottommost end of the inner cavity of the cylinder body.

[0042] The exhaust pipeline and the residual liquid backpressure pipeline can exist as the same pipeline.

[0043] The liquid outlet ends of multiple filter elements in the cylinder body are connected to a summary pipeline, which collects and exports the filtered liquid of multiple filter elements. The liquid outlet pipeline of the cylinder body, the cleaning pipeline 8, and the third gas supply pipeline 7 are all connected to the filter elements through the liquid outlet of the summary pipeline of several filter elements. Specifically, the liquid outlet pipeline, the cleaning pipeline 8, the third gas supply pipeline 7, and the summary pipeline are connected through a four-way joint.

[0044] In order to reduce the drilling of the bottom of the cylinder body, the residual liquid return pipeline and the liquid inlet pipeline are connected to the bottom of the inner cavity of the cylinder body through a connecting pipe.

[0045] In this embodiment, a number of residue-free filter cartridges 2 are arranged in parallel between the transfer pump and the precision filter 3. The multiple residue-free filter cartridges 2 work alternately. When a residue-free filter cartridge 2 is being regenerated, there needs to be a residue-free filter cartridge 2 in the working state to improve the working efficiency of the system. Under the condition of multiple residue-free filter cartridges 2 arranged in parallel, since the filtered stock solution continuously enters the precision filter 3 and then enters the purified liquid tank 4 from the precision filter 3, at this time, there is no need to set a transfer pump on the cleaning pipeline 8, and the power is provided by the transfer pump at the front end of the residue-free filter cartridge 2 in the working state (it is necessary to close the valve between the precision filter 3 and the purified liquid tank 4; when only one residue-free filter cartridge 2 is set or multiple residue-free filter cartridges 2 are connected in series, it is necessary to set a transfer pump on the cleaning pipeline 8 to provide power).

[0046] The liquid outlet pipeline of the cylinder body and the liquid outlet pipeline of the precision filter 3 are both connected to the stock solution tank 1 through branch pipelines, so as to re-feed the filtered liquid into the stock solution tank 1 for repeated filtration to improve the filtration effect, and valves are arranged on the branch pipelines.

[0047] The liquid outlet pipeline of the purified liquid tank 4 is connected to the stock solution tank 1 through a branch pipeline, and the purified liquid can be re-fed into the stock solution tank 1 to wait for re-filtration.

[0048] A flowmeter is arranged on the liquid outlet pipeline of the cylinder body to detect the flow rate in real time. When the flow rate decreases, it indicates that the filter element in the cylinder body is blocked. A flowmeter is also arranged on the liquid outlet pipeline of the purified liquid tank 4 to detect the liquid outlet flow rate.

[0049] In this system, each valve is controlled by a control system to improve the automation degree of the system.

[0050] The present invention also provides a solid-liquid separation and regeneration method for a soilless filtration system using the above-mentioned stock solution regeneration soilless filtration system, including the following steps:

[0051] S1: The control system controls the stop of the liquid inlet of the liquid inlet pipeline, opens the residual liquid return pipeline and the first air supply pipeline 6. The air enters the cylinder body to occupy the space in the cylinder body, and the stock solution in the cylinder body is pressed out from the residual liquid return pipeline. The pressed-out stock solution is collected and waiting for the next filtration;

[0052] S2: After the original liquid is pressed out, the control system controls the closing of the residual liquid return pipeline and the first air supply pipeline 6, opens the second air supply pipeline 9 and the exhaust pipeline. When the gas moves from bottom to top, it passes through the position where the filter element is located, and the filter cake is blown and solidified by the way of air flow;

[0053] S3: After the blowing and solidifying are completed, close the second air supply pipeline 9 and the exhaust pipeline, open the third air supply pipeline 7 and the solid discharge valve 10, and blow off and discharge the filter cake and the impurities outside the filter element to complete the solid-liquid separation;

[0054] S4: After the filter cake is discharged, close the third air supply pipeline 7 and the solid discharge valve 10, open the cleaning pipeline 8 and the residual liquid return pipeline, and the original liquid flows from inside the filter element to inside the cylinder, in the opposite direction to the flow direction of the filtrate, to achieve reverse cleaning and clean the residual impurities on the filter membrane of the filter element.

[0055] If the system needs to be shut down subsequently, after the cleaning in step S4 is completed, close the cleaning pipeline 8 and open the first air supply pipeline 6, and the original liquid inside the cylinder is pressed out; after the original liquid is completely pressed out, close the first air supply pipeline 6 and the residual liquid return pipeline, open the second air supply pipeline 9 and the residual liquid discharge pipeline 5, and the gas enters the inner cavity of the filter element from inside the cylinder. As the gas in the inner cavity of the filter element increases, the residual liquid inside the filter element is pressed out from inside the filter element to achieve the discharge of the residual liquid inside the filter element to the original liquid tank 1.

[0056] The adaptive changes made according to actual requirements are all within the protection scope of the present invention.

[0057] It should be noted that for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the present invention. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0058] Specific examples are used in the present invention to elaborate on the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, there will be changes in the specific implementation manners and application scopes according to the idea of the present invention. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A stock solution regeneration soilless filtration system, characterized in that, It includes a stock solution tank, a transfer pump, at least one residue-free filter cartridge, and a purified liquid tank that are connected in sequence. The residue-free filter cartridge includes a cylinder body and a filter element. The filter element is vertically arranged in the cylinder body. A solid discharge port and a liquid inlet pipeline are provided at the bottom of the cylinder body, and a liquid outlet pipeline, a cleaning pipeline, and a third air supply pipeline that are all connected to the filter element are provided at the top. A solid discharge valve is provided at the solid discharge port. The top inner cavity of the cylinder body is connected to a first air supply pipeline, and a residue liquid return pipeline is connected to the bottom inner cavity of the cylinder body. Valves are provided on the liquid inlet pipeline of the cylinder body, the liquid outlet pipeline of the cylinder body, the cleaning pipeline, the first air supply pipeline, the residue liquid return pipeline, and the third air supply pipeline. The purified liquid tank is connected to the cleaning pipeline.

2. The stock solution regeneration soil-less filtration system according to claim 1, characterized in that, The residue-free filter cartridge is connected to the purified liquid tank through a precision filter.

3. The stock solution regeneration soil-free filtration system according to claim 2, characterized in that, The purified liquid tank is connected to the cleaning pipeline and the liquid outlet pipeline of the precision filter through a pump body and a filter respectively.

4. The undiluted solution regeneration soil-less filtration system according to claim 2, wherein The pipeline between the precision filter and the purified liquid tank is connected to the cleaning pipeline, and valves are provided on both the connecting pipeline between the precision filter and the cleaning pipeline and the connecting pipeline between the precision filter and the purified liquid tank.

5. The undiluted solution regeneration soil-less filtration system according to claim 1, wherein A discharge pipeline is provided at the bottom of the purified liquid tank, and a purified liquid transfer pump and a valve body are provided on the discharge pipeline. The purified liquid transfer pump and the valve body of the discharge pipeline are both electrically connected to a control system.

6. The undiluted solution regeneration soil-free filtration system according to claim 1, wherein, A second air supply pipeline is connected to the bottom inner cavity of the cylinder body, and a valve is provided on the second air supply pipeline.

7. The undiluted solution regeneration soil-less filtration system according to claim 6, wherein, The first air supply pipeline, the second air supply pipeline, and the third air supply pipeline are all connected to a compressed gas supply device through a main air supply pipeline, and a pressure regulating valve for controlling pressure is provided on the main air supply pipeline.

8. The undiluted solution regeneration soil-free filtration system according to claim 6, wherein, A residue liquid discharge pipeline is provided at the top of the cylinder body. The liquid outlet of the residue liquid discharge pipeline is connected to the stock solution tank, and the liquid inlet is located at the bottom inner cavity of the filter element.

9. A method for solid-liquid separation and regeneration of a soilless filtration system, characterized in that, Applying the stock solution regeneration soil-free filtration system according to claim 8, it includes the following steps: S1: Stop the liquid inlet of the liquid inlet pipeline, open the residue liquid return pipeline and the first air supply pipeline, and the stock solution in the cylinder body is pressed out. S2: After the stock solution is pressed out, close the residue liquid return pipeline and the first air supply pipeline, open the second air supply pipeline and the exhaust pipeline, and blow and solidify the filter cake. S3: After the blowing and solidifying is completed, close the second air supply pipeline and the exhaust pipeline, open the third air supply pipeline and the solid discharge valve, the gas blows from inside the filter element to the inside of the cylinder body, opposite to the flow direction of the filtered liquid, to realize backwashing. During the backwashing process, the filter cake and the impurities outside the filter element are blown off and discharged from the solid discharge port to complete solid-liquid separation. S4: After the filter cake is discharged, close the third air supply pipeline and the solid discharge valve, open the cleaning pipeline and the residue liquid return pipeline, and the stock solution cleans the remaining impurities.

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