Filter press with backwashing function for industrial wastewater treatment

Abstract

This invention relates to the field of industrial wastewater treatment technology and discloses a filter press for industrial wastewater treatment with a backwashing function. The filter press includes a filter sleeve, a hollow shaft rotatably mounted inside the filter sleeve, a central feed pipe fixedly connected to the top of the hollow shaft, several water distribution pipes circumferentially arranged at the lower part of the hollow shaft, and an annular filter bag concentrically arranged outside the hollow shaft. A liquid collection chamber is provided between the annular filter bag and the inner wall of the filter sleeve. This invention utilizes an adaptive mechanism of "increased filtration resistance → increased liquid level" to convert resistance into hydrostatic squeezing power, significantly improving the dewatering effect. It achieves self-driven backwashing by accumulating filtrate and completes deep cleaning by forming a cross-flow field through bidirectional inclined nozzles. This design realizes automatic switching of the entire process from filtration and pressing to cleaning, reducing energy consumption while extending the service life of the filter bags and ensuring continuous and stable wastewater treatment efficiency.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater treatment technology, specifically to a filter press for industrial wastewater treatment with a backwashing function. Background Technology

[0002] As a mature solid-liquid separation device, the filter press plays an indispensable role in industrial wastewater treatment. It effectively separates solid particles from liquid in suspension using filter media such as filter cloth or membrane under pressure, offering significant advantages such as large processing capacity and high dewatering efficiency. Modern filter presses have made significant progress in structural optimization and automated control. For example, they employ different structures such as chamber, plate and frame, or belt filters to adapt to diverse operating conditions, and can be automated through PLC control systems to achieve automated operation of processes such as filtration and unloading.

[0003] In modern industrial wastewater treatment, filter presses, as the core equipment for solid-liquid separation, achieve stable treatment results through filter cloth interception and mechanical compression. Existing technologies employ modular design and automated control, significantly improving the ease of operation and efficiency, providing reliable technical support for industrial wastewater treatment. However, with the increasing complexity of the materials being treated, existing devices are gradually showing limitations in treating high-viscosity, high-solids-content wastewater. On the one hand, traditional fixed water distribution methods easily lead to uneven filter cake thickness, with dense filter cake layers forming prematurely in localized areas, increasing filtration resistance and significantly raising subsequent dewatering energy consumption. On the other hand, systems generally rely on external power sources for filter cloth cleaning; the backwashing process consumes additional water and electricity, and the unidirectional rinsing mode has relatively limited effectiveness in removing fine particles deeply embedded in the filter cloth.

[0004] Therefore, to address the shortcomings of existing technologies, we propose a filter press for industrial wastewater treatment with a backwashing function. Summary of the Invention

[0005] This invention provides a filter press for industrial wastewater treatment with a backwashing function. Through an adaptive mechanism of "increased filtration resistance → increased liquid level," the resistance is converted into hydrostatic squeezing power, significantly improving dewatering efficiency. Self-driven backwashing is achieved by accumulating filtrate, and deep cleaning is accomplished by forming a cross-flow field through bidirectional inclined nozzles. This design realizes fully automated switching from filtration and pressing to cleaning, reducing energy consumption while extending the filter bag's lifespan, ensuring continuous and stable wastewater treatment efficiency, and solving the problems mentioned in the background section.

[0006] This invention provides the following technical solution: a filter press for industrial wastewater treatment with backwashing function, comprising a filter press sleeve, a hollow shaft rotatably mounted inside the filter press sleeve, a central feed pipe fixedly connected to the top of the hollow shaft, a plurality of water distribution pipes circumferentially opened at the lower part of the hollow shaft, an annular filter bag concentrically arranged outside the hollow shaft, and a liquid collection chamber provided between the annular filter bag and the inner wall of the filter press sleeve; A receiving cavity is provided between the hollow shaft and the central feed pipe. A bypass pipe is provided between the receiving cavity and the liquid collection cavity. A first control valve is provided inside the bypass pipe. A first liquid outlet is provided at the bottom of the filter press sleeve. A second control valve is installed at the first liquid outlet.

[0007] As an optional solution for a filter press with backwashing function for industrial wastewater treatment according to the present invention, wherein: a backwashing manifold is provided inside the annular filter bag, the backwashing manifold is connected to the receiving cavity, a cleaning nozzle is provided on the backwashing manifold, and a third control valve is provided in the second liquid outlet of the annular filter bag that is connected to the outside, the third control valve being linked with the first control valve for control.

[0008] As an optional solution for a filter press with backwashing function for industrial wastewater treatment according to the present invention, wherein: the water distribution pipe radially penetrates the wall of the hollow shaft tube.

[0009] As an optional solution for a filter press with backwashing function for industrial wastewater treatment according to the present invention, the cleaning nozzle includes an inclined downward nozzle disposed at the upper end of the annular filter bag and an inclined upward nozzle disposed at the lower end of the annular filter bag.

[0010] As an optional solution for a filter press for industrial wastewater treatment with backwashing function as described in this invention, wherein: a limiting groove is provided on the inner wall of the top of the filter press sleeve, and extrusion protrusions are arranged in a circular array inside the limiting groove.

[0011] As an optional solution for a filter press for industrial wastewater treatment with backwashing function as described in this invention, wherein: a squeezing roller is provided on the inner wall of the annular filter bag, and the squeezing roller is fixedly connected to the hollow shaft through a connecting rod.

[0012] As an optional solution for a filter press for industrial wastewater treatment with backwashing function as described in this invention, wherein: a positioning component is installed at the upper end of the hollow shaft, and a squeezing slide rod is provided inside the positioning component for limiting sliding.

[0013] As an optional solution for a filter press for industrial wastewater treatment with backwashing function as described in this invention, a connecting spring is provided between the extrusion slide and the positioning component.

[0014] As an optional solution for a filter press with backwashing function for industrial wastewater treatment according to the present invention, wherein: a limiting annular groove is formed on the top surface of the annular filter bag, and the lower end of the extrusion slide rod is disposed inside the limiting annular groove.

[0015] As an optional solution for a filter press for industrial wastewater treatment with backwashing function as described in this invention, wherein the upper end of the extrusion slide rod is slidably disposed inside the limiting slide groove.

[0016] The present invention has the following beneficial effects: 1. This industrial wastewater treatment filter press with backwashing function cleverly utilizes the inherent physical mechanism of "increased filtration resistance → natural rise in liquid level" to achieve significant benefits in terms of energy efficiency, adaptive operation, and thorough self-cleaning. The system converts filtration resistance into hydrostatic pressure, automatically enhancing dewatering at the end of filtration and significantly reducing the moisture content of the filter cake. Simultaneously, it uses the accumulated filtrate as a backwash water source, forming a cross-flow field through unique bidirectional inclined nozzles to achieve deep cleaning of the filter bags. Throughout the process, the device can automatically switch between filtration, pressing, and cleaning processes based on the filter cake's formation state without external intervention. This not only significantly reduces energy consumption and operating costs but also effectively extends the filter bag's lifespan, ensuring continuous and stable wastewater treatment efficiency.

[0017] 2. This industrial wastewater treatment filter press with backwashing function achieves a comprehensive improvement in filtration efficiency by adding rotating extrusion rollers and a high-frequency micro-vibration unclogging system. The synergistic effect of rotating water distribution and synchronous mechanical extrusion not only forms a uniformly structured filter cake, improving filtration efficiency and dewatering degree, but also maintains filter cake permeability through continuous rolling pressure. The high-frequency micro-vibration mechanism integrated into the hollow shaft converts rotational kinetic energy into periodic, slight vibrations on the filter bag, removing deep-seated clogging particles from the fibers online without interrupting filtration, significantly delaying the increase in resistance, and thus effectively improving filtration time. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the first cross-sectional structure of the partial filter press sleeve of the present invention; Figure 3 For the present invention Figure 2 Enlarged structural diagram at point A in the middle; Figure 4 For the present invention Figure 2 Schematic diagram of the enlarged structure of the hollow shaft in the middle section; Figure 5 This is a schematic diagram of the second cross-sectional structure of the partial filter press sleeve of the present invention; Figure 6 For the present invention Figure 5Enlarged structural diagram at point B; Figure 7 For the present invention Figure 5 Enlarged structural diagram at point C; Figure 8 This is a schematic diagram of the annular filter bag structure of the present invention.

[0019] In the diagram: 1. Filter press sleeve; 101. Hollow shaft; 102. Central feed pipe; 103. Water distribution pipe; 104. Liquid collection chamber; 105. Receiving chamber; 106. Bypass pipe; 107. First liquid outlet; 108. Second liquid outlet; 109. Backwash manifold; 110. Cleaning nozzle; 111. Annular filter bag; 112. Limiting slide groove; 113. Extrusion slide bar; 114. Connecting spring; 115. Extrusion roller; 116. Limiting ring groove; 117. Positioning component; 118. Extrusion protrusion; 119. First control valve; 120. Second control valve; 121. Third control valve. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1, please refer to Figures 1-8 To better treat industrial wastewater, the present invention provides a radial flow filter press device. The device mainly includes a filter press sleeve 1. The top and bottom of the filter press sleeve 1 are sealed and fixed by a mounting plate. A hollow shaft 101 is rotatably installed inside the filter press sleeve 1. A central feed pipe 102 is fixedly connected to and communicates with the top of the hollow shaft 101. The upper end of the central feed pipe 102 extends to the outside of the filter press sleeve 1 for connection to an external pressure pipeline.

[0022] At the lower part of the hollow shaft 101, a number of water distribution pipes 103 are arranged in a circumferentially equidistant array. These water distribution pipes 103 penetrate the pipe wall of the hollow shaft 101 radially. An annular filter bag 111 is concentrically arranged on the outside of the hollow shaft 101. A liquid collection chamber 104 is provided between the annular filter bag 111 and the inner wall of the filter press sleeve 1.

[0023] Meanwhile, since a receiving cavity 105 is provided between the hollow shaft 101 and the central feed pipe 102, and a bypass pipe 106 is provided between the receiving cavity 105 and the liquid collection cavity 104, it should be noted that a first control valve 119 is provided inside the bypass pipe 106, and a first liquid outlet 107 communicating with the outside is provided at the bottom of the filter press sleeve 1, and a second control valve 120 is installed in the first liquid outlet 107.

[0024] Because pressurized industrial wastewater is introduced through the central feed pipe 102 and then evenly sprayed radially into the annular filter bag 111 through the water distribution pipe 103, the wastewater undergoes radial flow from the inside to the outside under pressure. The liquid passes through the annular filter bag 111 to become filtrate. It should be noted that at this time, the first control valve 119 located inside the bypass pipe 106 is closed, while the second control valve 120 located inside the first outlet 107 is open. Therefore, the filtrate entering the collection chamber 104 will be discharged from the filter press sleeve 1 through the first outlet 107. During this process, solid particles are trapped to form an annular filter cake. As filtration continues, the filter cake gradually thickens, and the filtration resistance increases. It should be noted that the second control valve 120 is opened to a preset opening degree at this time. The wastewater is pressurized by a booster pump and injected into the central feed pipe 102 at a relatively constant flow rate. The wastewater enters the annular filter bag 111 through the central feed pipe 102 and the water distribution pipe 103. Under the pump pressure, the liquid passes through the annular filter bag 111 and enters the collection chamber 104, becoming filtrate. Finally, it is discharged through the first outlet 107. At this time, the system is in a dynamic equilibrium. Since the total resistance driving the flow of filtrate is composed of the filtration resistance formed by the annular filter bag 111 and the initial filter cake on its surface, and the valve resistance determined by the opening degree of the second control valve 120, and since the filter cake is extremely thin at the beginning of filtration, the filtration resistance is very small and the total system resistance is low. Therefore, the filtrate can flow out smoothly, and its instantaneous flow rate can be close to the feed flow rate, so the liquid level in the system can be maintained stably.

[0025] However, as the filtration process continues, solid particles accumulate on the inner surface of the annular filter bag 111, forming and thickening a filter cake layer. This gradually densifying filter cake layer drastically increases the difficulty for fluid to pass through, resulting in a continuous and significant increase in filtration resistance. According to basic principles of fluid mechanics, under essentially constant driving pressure, the flow rate through a system is inversely proportional to its total resistance. Therefore, although the feed pump continues to inject water into the system at a constant flow rate, the ever-increasing total resistance causes an irreversible and gradual decrease in the instantaneous output flow rate of the filtrate. This disrupts the initial equilibrium, causing the amount of water entering the system per unit time to begin to exceed the amount leaving the system.

[0026] The excess water that cannot be discharged in time will inevitably accumulate in the collection chamber 104 of the filter press sleeve 1, causing the internal liquid level to rise steadily and continuously. This phenomenon is not a malfunction, but a physical response of the system to changes in filtration resistance. This rising liquid level produces a dual beneficial effect: First, it applies a gradually increasing hydrostatic pressure to the outer wall of the annular filter bag 111. This pressure is transmitted through the annular filter bag 111 to the internal filter cake, forming a "hydraulic squeezing" effect from the outside in, thereby further enhancing dewatering at the end of filtration and significantly reducing the final moisture content of the filter cake.

[0027] When the liquid level rises to the preset maximum backwash level, it indicates that the filter cake has reached its maximum thickness or the annular filter bag 111 is nearing blockage, and the filtration cycle should end. At this time, the system automatically switches to backwash mode: on the one hand, it stops feeding material into the central feed pipe 102; on the other hand, it closes the second control valve 120 to completely block the filtrate outlet, while simultaneously opening the first control valve 119. This operation instantly changes the flow path of the system. The high-level filtrate that had previously accumulated in the collection chamber 104 immediately flows into the receiving chamber 105 through the bypass pipe 106 under the combined drive of its own gravity and the residual feed pressure of the system.

[0028] Because two backwash manifolds 109 are fixedly installed inside the annular filter bag 111, with the two backwash manifolds 109 respectively located at the upper and lower ends of the annular filter bag 111, and each backwash manifold 109 is connected to the interior of the receiving cavity 105, and the backwash manifold 109 located at the upper end of the annular filter bag 111 is also equipped with a downward-sloping cleaning nozzle 110, while the backwash manifold 109 located at the lower end of the annular filter bag 111 is equipped with an upward-sloping cleaning nozzle 110, the cleaning nozzle... Each head 110 is connected to a corresponding backwash manifold 109. This means that the filtrate entering the receiving chamber 105 will pass through the receiving chamber 105 and the backwash manifold 109, and finally be sprayed at high speed onto the inner surface of the annular filter bag 111 via the upward and downward tilting cleaning nozzles 110. This powerful flow of liquid can efficiently flush, break down, and peel off the filter cake adhering to the inner surface of the annular filter bag 111, while simultaneously removing particles clogging deep within the fibers of the annular filter bag 111, thus completing a thorough backwash. The annular filter bag 111 is also connected to the outside via a second outlet 108. A third control valve 121 is installed inside the second outlet 108, and the third control valve 121 will only open synchronously when the first control valve 119 is open. This means that the dispersed contaminants will be discharged from the filter press sleeve 1 along with the wastewater through the second outlet 108.

[0029] It should be noted that the first control valve 119, the second control valve 120, and the third control valve 121 are all technologies commonly used and existing in the art. Users can make adjustments according to actual conditions and their own needs, and will not elaborate further here.

[0030] In summary, this invention transforms the traditionally unfavorable factor of increased filtration resistance into a beneficial driving force for backwashing by precisely utilizing the inherent physical process of "increased filtration resistance → spontaneous decrease in effluent flow rate → natural rise in liquid level," thus constructing an energy-saving, efficient, and highly adaptive solid-liquid separation and device self-cleaning solution.

[0031] Example 2: This example aims to further improve the treatment effect of industrial wastewater. It is an improvement upon Example 1. For details, please refer to [link / reference]. Figures 1-8 Because a squeezing roller 115 is installed on the inner wall of the annular filter bag 111, the squeezing roller 115 is firmly connected to the hollow shaft 101 through a rigid connecting rod. Furthermore, the bottom of the hollow shaft 101 is directly connected to the output end of an external motor. This means that when the system starts working, the user can control the external motor to drive the hollow shaft 101 to rotate. This rotational motion significantly improves the filtration effect through two pathways. First, because the water distribution pipe 103 passes through the hollow shaft 101 and remains connected to the central feed pipe 102, the rotation of the hollow shaft 101 drives the movement of the entire water distribution system, resulting in the wastewater entering the system undergoing radial flow combined with rotational motion. This composite flow pattern ensures that the wastewater can uniformly cover the entire inner surface of the annular filter bag 111 in a three-dimensional manner, thus solving to some extent the "channeling" and "dead zone" problems that are prone to occur in traditional fixed water distribution methods. Its direct effect is to promote the uniform deposition of solid particles throughout the entire height and circumference of the filter bag, forming an annular filter cake with extremely uniform thickness and density. This not only significantly improves the utilization rate of the filtration area, but also lays an ideal foundation for subsequent processes.

[0032] Secondly, as the hollow shaft 101 continues to rotate, the compression roller 115, which is fixedly connected to it via a connecting rod, synchronously performs circumferential motion, tightly adhering to the inner wall of the annular filter bag 111 and rotating accordingly. This design achieves continuous mechanical compression during the filtration process, with advantages in several aspects: in the initial stage of filtration, the gentle rolling of the compression roller 115 promotes the uniform distribution of solid particles; as the filter cake forms, moderate mechanical pressure helps to expel some of the bound water inside the filter cake, effectively increasing the solid content; more importantly, this dynamic compression action can maintain the porous structure of the filter cake, preventing over-densification and thus maintaining a relatively stable filtration flux.

[0033] This method of combining water distribution optimization with mechanical dewatering not only improves the efficiency of current filtration, but also makes subsequent backwashing cleaning more thorough and efficient. The flat and uniform filter cake surface also avoids the cleaning difficulties caused by excessively thick or hard local areas, thus effectively improving the overall operating efficiency of the system.

[0034] Meanwhile, to improve the continuous operating efficiency and stability of the radial flow filter press in treating industrial wastewater, this solution also includes a high-frequency micro-vibration automatic clogging system based on mechanical transmission. This system integrates the filtration process with online self-cleaning through a precise mechanical linkage design. Its core lies in utilizing the rotational power of the hollow shaft 101 to drive a unique slide-cam mechanism, achieving continuous maintenance-style cleaning of the annular filter bag 111.

[0035] Specifically, an annular limiting groove 112 is machined on the inner wall of the top of the filter press sleeve 1, with a specific contour extrusion protrusion 118 arranged in a circular array inside. Correspondingly, an axially sliding extrusion slide rod 113 is installed on the upper end of the hollow shaft 101 through symmetrically arranged positioning members 117. The extrusion slide rod 113 and the positioning members 117 are connected by a connecting spring 114 to ensure automatic reset capability. A limiting annular groove 116 is opened on the top surface of the annular filter bag 111, and the lower end of the extrusion slide rod 113 is arranged in a vertically sliding manner inside the limiting annular groove 116.

[0036] When the equipment is running, the rotation of the hollow shaft 101 drives the extrusion slide rod 113 to revolve synchronously. The upper end of the extrusion slide rod 113 slides in the limiting slide groove 112. Once it contacts the extrusion protrusion 118, it is quickly pressed down under the guidance of the inclined surface, which then generates a high-frequency, low-amplitude slight vibration on the bottom surface of the limiting ring groove 116. This periodic and evenly distributed slight vibration can effectively shake off the fine particles that are blocked deep in the fibers of the annular filter bag 111. At the same time, because its force is controllable, it avoids potential damage to the filter bag structure. After the extrusion slide rod 113 passes the highest point of the extrusion protrusion 118, it quickly resets under the action of the connecting spring 114, completing one complete impact cycle.

[0037] The ingenuity of this design lies in transforming continuous rotational motion into high-frequency micro-mechanical vibration, which offers several key advantages. First, this periodic high-frequency micro-vibration effectively breaks down fine particles deep within the filter bag fibers, achieving continuous online cleaning without interrupting the filtration process. This significantly slows the rate of increase in filtration resistance, allowing the system to maintain high-efficiency filtration for extended periods, thereby greatly improving overall processing efficiency and reducing backwashing frequency. Simultaneously, this "high-frequency, low-amplitude" action is evenly distributed and the impact force is controllable, avoiding potential damage to the filter bags caused by traditional cleaning methods and significantly extending their lifespan. Furthermore, the slight vibration helps optimize the filter cake structure, maintaining better porosity and permeability, creating favorable conditions for filtration and subsequent dewatering stages.

[0038] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0039] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A filter press for industrial wastewater treatment with backwashing function, comprising a filter press sleeve (1), characterized in that: A hollow shaft (101) is rotatably installed inside the filter press sleeve (1). A central feed pipe (102) is fixedly connected to the top of the hollow shaft (101). Several water distribution pipes (103) are opened circumferentially at the bottom of the hollow shaft (101). An annular filter bag (111) is concentrically arranged outside the hollow shaft (101). A liquid collection chamber (104) is provided between the annular filter bag (111) and the inner wall of the filter press sleeve (1). A receiving cavity (105) is provided between the hollow shaft (101) and the central feed pipe (102). A bypass pipe (106) is provided between the receiving cavity (105) and the liquid collection cavity (104). A first control valve (119) is provided inside the bypass pipe (106). A first liquid outlet (107) is provided at the bottom of the filter press sleeve (1). A second control valve (120) is installed at the first liquid outlet (107).

2. A filter press for industrial wastewater treatment with backwashing function according to claim 1, characterized in that: The annular filter bag (111) is provided with a backwash manifold (109) inside, which is connected to the receiving cavity (105). A cleaning nozzle (110) is provided on the backwash manifold (109). A third control valve (121) is provided in the second liquid outlet (108) of the annular filter bag (111) that is connected to the outside. The third control valve (121) is linked to the first control valve (119) for control.

3. A filter press for industrial wastewater treatment with backwashing function according to claim 1, characterized in that: The water distribution pipe (103) radially penetrates the wall of the hollow shaft (101).

4. A filter press for industrial wastewater treatment with backwashing function according to claim 1, characterized in that: The cleaning nozzle (110) includes a downward-sloping nozzle located at the upper end of the annular filter bag (111) and an upward-sloping nozzle located at the lower end of the annular filter bag (111).

5. A filter press for industrial wastewater treatment with backwashing function according to claim 1, characterized in that: The filter press sleeve (1) has a limiting groove (112) on the inner wall of the top, and the limiting groove (112) has extrusion protrusions (118) arranged in a circular array inside.

6. A filter press for industrial wastewater treatment with backwashing function according to claim 5, characterized in that: The inner wall of the annular filter bag (111) is provided with a squeezing roller (115), and the squeezing roller (115) is fixedly connected to the hollow shaft (101) through a connecting rod.

7. A filter press for industrial wastewater treatment with backwashing function according to claim 6, characterized in that: A positioning component (117) is installed on the upper end of the hollow shaft (101), and a compression slide rod (113) is provided inside the positioning component (117) for limiting sliding.

8. A filter press for industrial wastewater treatment with backwashing function according to claim 7, characterized in that: A connecting spring (114) is provided between the compression slide bar (113) and the positioning member (117).

9. A filter press for industrial wastewater treatment with backwashing function according to claim 8, characterized in that: The top surface of the annular filter bag (111) is provided with a limiting annular groove (116), and the lower end of the extrusion slide bar (113) is located inside the limiting annular groove (116).

10. A filter press for industrial wastewater treatment with backwashing function according to claim 9, characterized in that: The upper end of the extrusion slide bar (113) is slidably disposed inside the limiting slide groove (112).

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