A cross-flow filtration test device

Abstract

This utility model relates to a cross-flow filtration testing device, comprising a feed tank, a water pump, and at least one filter bed arranged in a closed loop via pipelines. The filter bed contains a flat membrane, which divides the filter bed into an upper chamber and a lower chamber. The upper chamber has a filter bed inlet and a filter bed outlet located opposite each other. The feed liquid in the feed tank is pumped into the filter bed by the water pump and flows parallel to the membrane. The feed liquid filtered by the membrane enters the lower chamber, while the unfiltered feed liquid flows back into the feed tank. A rotating disturbance component is provided between the filter bed inlet and outlet, and a driving structure is provided on the rotating disturbance component. During testing, the feed liquid flowing parallel to the membrane applies a driving force to the driving structure, driving the rotating disturbance component to rotate and forming a rotating flow field that disturbs the feed liquid. This utility model can effectively disturb the membrane surface, ensuring a uniform feed liquid flow rate while removing particles deposited on the membrane surface.

Description

Technical Field

[0001] This utility model relates to a cross-flow filtration testing device, belonging to the field of membrane separation testing equipment. Background Technology

[0002] Currently, cross-flow filtration has become the mainstream method for membrane performance evaluation due to its ability to effectively mitigate concentration polarization and enhance membrane surface shear. Although cross-flow testing devices exist for laboratory and pilot-scale applications, their filter structures are simple, and the liquid flow is mostly linear, making it difficult to create sufficient disturbance on the membrane surface, which can easily lead to localized concentration polarization and biased test results. Furthermore, existing devices are generally large in size and require the membrane to be assembled into a finished product before performance testing, resulting in high costs and cumbersome maintenance, which is not conducive to conducting high-frequency, small-sample, and multi-condition flexible testing in laboratory settings.

[0003] Chinese Patent No. CN201669063U discloses a cross-flow filtration device and system, including an upper cover with a boss and a cross-flow groove on the surface of the boss. The cross-flow groove has a uniform width and includes an inlet and a return outlet communicating with the cross-flow groove. A bottom cover has a concave surface adapted to the boss, with several evenly distributed converging grooves and a converging channel communicating with the converging grooves and an outlet on the bottom cover. At least one locking fastener is also included to secure the upper and bottom covers. The cross-flow grooves can evenly deliver the liquid to be filtered to the surface of the filter membrane, while the converging grooves of the bottom cover can evenly collect the filtered liquid. However, solutes or particulate matter easily deposit in the grooves, resulting in severe local concentration polarization. Utility Model Content

[0004] To overcome the above problems, this utility model provides a cross-flow filtration testing device that can effectively turbulentize the membrane surface, achieve a stable cross-flow field in a limited space, and has flexible control capabilities.

[0005] The technical solution of this utility model is as follows: A cross-flow filtration testing device includes a feed tank, a water pump, and at least one filter bed, which are connected in series and arranged in a closed loop via pipelines. The filter bed contains a flat-laid membrane, which divides the filter bed into an upper chamber and a lower chamber. The upper chamber has a filter bed inlet and a filter bed outlet located opposite each other. The feed liquid in the feed tank is pumped into the filter bed by the water pump and flows parallel to the membrane. The feed liquid filtered by the membrane enters the lower chamber, while the unfiltered feed liquid flows back into the feed tank. A rotating disturbance component is provided between the filter bed inlet and the filter bed outlet. The rotating disturbance component has a driving structure. During testing, the feed liquid flowing parallel to the membrane applies a driving force to the driving structure, driving the rotating disturbance component to rotate and forming a rotating flow field that disturbs the feed liquid.

[0006] Furthermore, the rotating disturbance component includes a sleeve concentrically arranged with the upper chamber, and a plurality of blades radially fixedly connected around the sleeve; the sleeve is arranged perpendicular to the diaphragm, and a rotating shaft is detachably connected inside the sleeve, the rotating shaft is connected to a fixed frame, and the fixed frame is fixedly connected to the upper chamber; a guide channel for the feed liquid is formed between adjacent blades.

[0007] Furthermore, the driving structure is a driving surface that forms an angle with the direction of liquid flow, and the liquid flow is parallel to the driving surface of the diaphragm flow, driving several blades to rotate around the rotating shaft.

[0008] Furthermore, the blades are set at an angle to the direction of liquid flow, and the driving surface is the blade surface at an angle to the direction of liquid flow.

[0009] Furthermore, the airfoil structure of the blade includes circular arcs, straight lines, or curves.

[0010] Furthermore, the fixing frame is a ring structure concentrically arranged with the upper chamber, its inner ring accommodating the rotating disturbance component, and its outer edge being fixedly connected to the upper chamber by bolts; a bearing is provided at the center of the inner ring, and the outer circumference of the bearing is fixedly connected to the outer edge by several connecting rods, and the bearing is placed below the sleeve; the rotating shaft is installed inside the bearing.

[0011] Furthermore, a support plate for supporting the membrane is provided between the upper chamber and the lower chamber, and the periphery of the support plate is fixedly connected to the inner wall of the filter tank; a permeate outlet is provided in the lower chamber, and the permeate outlet is connected to the collector through a permeate tube.

[0012] Furthermore, the material tank is provided with a material tank inlet at the top and a material tank outlet at the bottom. The material tank outlet is connected to the input end of the water pump, and the output end of the water pump is connected to the inlet of the filter tank. The material tank is also provided with a reflux port at the top, which is connected to the outlet of the filter tank. A thermometer is installed on the inner wall of the upper part of the material tank.

[0013] Furthermore, the pipeline connecting the input end of the water pump to the feed inlet of the filter tank is a feed pipe, and a feed regulating valve is installed on the feed pipe; the pipeline connecting the discharge outlet of the filter tank to the return outlet is a interception pipe, a interception regulating valve is installed on the interception pipe, and a pressure gauge is installed on the interception pipe connecting the interception regulating valve and the discharge outlet of the filter tank.

[0014] Furthermore, multiple filter tanks are arranged in parallel to form a filter tank group; the feed pipe has several feed branches connected to the feed inlets of each filter tank, and each feed branch is equipped with the feed regulating valve; the interception pipe has several interception branches connected to the discharge outlets of each filter tank, and each interception branch is equipped with the interception regulating valve; each interception regulating valve is connected to the discharge outlet of the filter tank with a pressure gauge, and the pressure gauge is installed on the adjacent interception branch.

[0015] This utility model has the following beneficial effects: 1. This utility model allows for direct membrane performance testing of the membrane body through a filter bed. It has a simple structure and is suitable for testing in confined spaces such as laboratories. It uses a water pump for dual closed-loop control of flow and pressure. Through the cooperation of the feed regulating valve, the intercept regulating valve and the pressure gauge, the pipeline pressure difference can be detected and adjusted to keep the pressure difference of the device pipeline consistent, meet the experimental accuracy control requirements, improve the flexibility and controllability of the test, and is suitable for high-frequency daily use.

[0016] 2. The filter of this utility model is equipped with a rotating disturbance component. The driving surface of the rotating disturbance component forms an angle with the feed liquid flowing parallel to the membrane. When it is washed by the feed liquid, it drives the rotating disturbance component to rotate, creating a rotating flow field, disturbing the feed liquid, driving the boundary layer flow, and preventing the formation of flow dead zones. At the same time, with the cooperation of the water pump and the rotating disturbance component, the feed liquid flow velocity is evenly distributed and generates strong shear force, which can remove the solute accumulation and precipitated particles on the membrane surface, avoid concentration polarization, and improve the stability and repeatability of test results. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0018] Figure 2 This is a schematic diagram of the overall structure of the filter bed.

[0019] Figure 3 This is a schematic diagram of the connection structure between the rotating disturbance component and the fixed frame.

[0020] Figure 4 This is a top view of the mounting bracket.

[0021] Figure 5 This is a schematic diagram of a blade with a straight airfoil.

[0022] Figure 6 This is a schematic diagram of a blade with a curved airfoil.

[0023] The reference numerals in the figure are as follows: 1. Feed tank; 2. Water pump; 3. Filter tank; 31. Upper chamber; 311. Filter tank inlet; 312. Filter tank outlet; 32. Lower chamber; 321. Permeate outlet; 33. Support plate; 4. Membrane; 5. Rotating agitator; 51. Sleeve; 52. Blade; 53. Shaft; 54. Fixing frame; 55. Bearing; 56. Connecting rod; 6. Permeate pipe; 7. Feed regulating valve; 8. Retention regulating valve; 9. Pressure gauge. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0025] See Figure 1-6 A cross-flow filtration test device includes a liquid tank 1, a water pump 2, and at least one filter tank 3 arranged in a closed loop via pipelines. The filter tank 3 is equipped with a flat membrane 4. During the test, the liquid in the liquid tank 1 is pumped to the filter tank 3 by the water pump 2. After entering the filter tank 3, the liquid flows parallel to the membrane surface. The membrane 4 filters the liquid. The liquid that does not pass through the membrane 4 is sent back to the liquid tank 1, merges with other liquids, and is filtered again.

[0026] Furthermore, the feed tank 1 is equipped with a feed inlet at the top and a discharge outlet at the bottom. The liquid enters the feed tank 1 through the feed inlet and flows out through the discharge outlet. The pipeline connecting the discharge outlet to the input of the water pump 2 is a delivery pipe. After passing through the delivery pipe, the liquid is pumped and pressurized by the water pump 2 and then transported to the filter tank 3. The flow rate and pressure of the liquid are controlled by the water pump 2 to simulate the membrane operation under different working conditions and meet different testing requirements.

[0027] Furthermore, the membrane sheet 4 laid flat inside the filter tank 3 is divided into upper and lower chambers 32. The upper chamber 31 is equipped with a filter tank inlet 311 and a filter tank outlet 312 located opposite each other. The pipeline used to connect the output end of the water pump 2 and the filter tank inlet 311 is a feed pipe. The feed liquid flows into the upper chamber 31 through the feed pipe and flows parallel to the membrane surface in the upper chamber 31. In order to maintain a consistent flow rate of the feed liquid to the filter tank 3, a feed regulating valve 7 is provided on the feed pipe to control the flow rate of the feed liquid being filtered.

[0028] The membrane 4 filters the flowing liquid. The liquid filtered by the membrane 4 is the permeate. The lower chamber 32 is used to contain the permeate. The bottom of the lower chamber 32 has a permeate outlet 321. The other end of the permeate outlet 321 is connected to the collector through the permeate tube 6 to discharge the permeate from the filter tank 3 and collect and store it.

[0029] Furthermore, the upper part of the feed tank 1 is also provided with a return port. The pipeline connecting the filter outlet 312 and the return port is a interception pipe. The feed liquid that does not pass through the membrane 4 flows back into the feed tank 1 through the interception pipe. The height difference allows the returned feed liquid to mix with the feed liquid in the feed tank 1 before flowing to the feed tank outlet for circulation filtration. A thermometer is also installed on the inner wall of the feed tank 1 to monitor the temperature of the feed liquid in real time.

[0030] Furthermore, to prevent changes in the dynamic pressure of the pipeline from affecting the test results during the testing process, a pressure gauge 9 is installed on the interception pipe. The pressure gauge 9 can be a digital display pressure gauge, which facilitates the observation of dynamic pressure changes and can also output the collected pressure values ​​to an external data acquisition device. An interception regulating valve 8 is also installed on the interception pipe, and the pressure gauge 9 is located between the interception regulating valve 8 and the filter tank 3. When a pressure change is observed, the pressure difference in the pipeline is kept consistent through the cooperation of the feed regulating valve 7 and the interception regulating valve 8, thereby reducing factors that may affect the test results.

[0031] Furthermore, there are multiple filter tanks 3 connected in parallel, which ensures consistent liquid concentration during synchronous filtration, improves test accuracy, and accelerates test efficiency. The feed pipe has multiple feed branches, each connected to the feed inlet 311 of each filter tank, and the interception pipe has multiple interception branches, each connected to the discharge outlet 312 of each filter tank. Each feed branch is equipped with the aforementioned feed regulating valve 7, and each interception branch is equipped with the aforementioned interception regulating valve 8, enabling flexible control of pipeline pressure differential. Each interception regulating valve 8 is connected to a filter tank discharge outlet 312 via a pressure gauge 9, which is installed on adjacent interception branches.

[0032] Furthermore, each filter 3 is provided with a support plate 33 for supporting the membrane 4. The periphery of the support plate 33 is fixedly connected to the inner wall of the filter 3. Several permeate channels are opened on the support plate 33. The best design is that the support plate 33 and the inner wall of the filter 3 are integrally formed to prevent unfiltered liquid from flowing into the lower chamber 32 from the periphery of the support plate. Alternatively, other fixed connection methods such as welding can be used to tightly fit the periphery of the support plate 33 to the inner wall of the filter 3.

[0033] Furthermore, a rotating disturbance element 5 is provided between the filter inlet 311 and the filter outlet 312 to disturb the liquid in the upper chamber 31, so as to avoid the formation of flow dead zones and severe local concentration polarization, which would affect the membrane's sequential flux, retention rate consistency and test reproducibility. The rotating disturbance element 5 is fixedly connected to the inner wall of the upper chamber 31 through a connecting plate.

[0034] The rotating agitator 5 is mounted in the upper chamber 31 via a fixing frame 54. The rotating agitator 5 includes a sleeve 51 concentrically arranged with the upper chamber 31, the sleeve 51 being perpendicular to the support plate 33, and several blades 52 radially fixedly connected around the sleeve 51, forming a guide channel for the feed liquid between adjacent blades 52. To achieve the rotation of the rotating agitator 5, a driving structure is provided between the sleeve 51 and the fixing frame 54, the driving structure being a driving surface forming an angle with the direction of feed liquid flow.

[0035] Furthermore, all blades 52 are set at an angle to the direction of liquid flow, and the driving surface is the blade surface that receives the impact of the liquid; for example, the blades 52 can be set perpendicular to the direction of liquid flow, or set at other inclined angles to the direction of liquid flow to receive the impact of the liquid; the airfoil structure of the blades 52 can be arc-shaped, and for ease of driving, the arc-shaped opening is set towards the filter inlet 311, or it can be straight (e.g. Figure 5 ), or curved (such as Figure 6 In the test state, when the liquid enters the upper chamber 31 and flows parallel to the diaphragm 4, the impacted blade surface drives the blade 52 to rotate, forming a rotating flow field, which enhances the flow of the liquid boundary layer. The faster the liquid flows, the faster the disturbance speed, and the stronger the shear force of the flow field.

[0036] Furthermore, the fixing frame 54 is an annular structure concentrically arranged with the upper chamber 31. Its inner ring accommodates the rotating disturbance component 5, and its outer edge is fixedly connected to the inner wall of the upper chamber 31 by bolts. A bearing 55 is installed at the center of the inner ring. The bearing 55 is placed below the sleeve 51. The outer circumference of the bearing 55 is fixedly connected to the outer edge by several cross-arranged connecting rods 56. A rotating shaft 53 is fixedly connected inside the bearing 55. The rotating shaft 53 is detachably connected to the sleeve 51. The fixing frame 54 is used to support the rotating disturbance component 5, and the annular structure can reduce the impact on the disturbance of the liquid flow field.

[0037] To ensure the stable support effect of the fixed frame 54, two arc-shaped plates are symmetrically arranged along its outer edge and fixedly connected to it. The arc-shaped plates are fixedly connected to the inner wall of the upper chamber 31, and the two arc-shaped plates are staggered with the filter tank inlet 311 and the filter tank outlet 312.

[0038] Furthermore, the shaft 53 and the sleeve 51 can be connected by threads, with the inner wall of the sleeve 51 having internal threads and the outer circumference of the shaft 53 having external threads that mate with it; the shaft 53 and the sleeve 51 can also be connected by an interference fit.

[0039] The working principle of this utility model: See Figure 1-6Before testing, membrane 4 is laid flat on support plate 33. During testing, the liquid in the feed tank 1 is pumped into filter tank 3 by water pump 2. After entering the upper chamber 31 of filter tank 3, the liquid flows parallel to membrane 4 and impacts blades 52, driving blades 52 to rotate around shaft 53. This creates a rotating flow field that disrupts the static fluid boundary layer near the membrane surface. The shear force generated by the rotation can remove solutes and particulate matter enriched on the membrane surface, maintaining the instantaneous flux of membrane 4.

[0040] The permeate formed after filtration by membrane 4 is collected in the lower chamber 32 and sent into the collector through the permeate tube 6. The unfiltered liquid is returned to the liquid tank 1 from the filter outlet 312 through the interception tube. After mixing with the liquid in the liquid tank 1, it is pumped back to the filter tank 3 for further filtration by the water pump 2.

[0041] During the test, the dynamic pressure changes between the feed pipe and the interception pipe were observed by observing pressure gauge 9, and the pressure of the two pipes was kept balanced by adjusting the feed regulating valve and the interception regulating valve.

[0042] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A cross-flow filtration testing device, comprising a liquid tank (1), a water pump (2), and at least one filter (3) arranged in a closed loop via pipelines connected in series; the filter (3) is divided into an upper chamber (31) and a lower chamber (32) by a membrane (4) laid flat within it; the upper chamber (31) is provided with a filter inlet (311) and a filter outlet (312) positioned opposite each other; the liquid in the liquid tank (1) is pumped into the upper chamber (31) by the water pump (2) and flows parallel to the membrane (4); the liquid filtered by the membrane (4) seeps into the lower chamber (32), and the liquid not filtered by the membrane (4) flows back into the liquid tank (1), characterized in that: A rotating disturbance component (5) is provided between the filter inlet (311) and the filter outlet (312). The rotating disturbance component (5) is provided with a driving structure. During the test, the liquid flowing parallel to the membrane (4) applies a driving force to the driving structure, driving the rotating disturbance component (5) to rotate and forming a rotating flow field to disturb the liquid.

2. The staggered flow filtration test device of claim 1, wherein: The rotating disturbance component (5) includes a sleeve (51) concentrically arranged with the upper chamber (31) and a plurality of blades (52) radially fixedly connected around the sleeve (51); the sleeve (51) is arranged perpendicular to the diaphragm (4), and a rotating shaft (53) is detachably connected inside the sleeve (51). The rotating shaft (53) is connected to a fixed frame (54), and the fixed frame (54) is fixedly connected to the upper chamber (31); a guide channel for the feed liquid is formed between adjacent blades (52).

3. The staggered flow filtration test device of claim 2, wherein: The driving structure is a driving surface that forms an angle with the direction of liquid flow. The liquid flow is parallel to the driving surface of the diaphragm (4) and drives several blades (52) to rotate around the rotating shaft (53).

4. The staggered flow filtration test device of claim 3, wherein: Each blade (52) is set at an angle to the direction of liquid flow, and the driving surface is the blade surface impacted by the liquid.

5. The staggered flow filtration test device of claim 4, wherein: The airfoil structure of the blade (52) includes arc, straight or curved shapes.

6. A staggered flow filtration test device according to claim 2 or 5, wherein: The fixing frame (54) is an annular structure concentrically arranged with the upper chamber (31). Its inner ring accommodates the rotating disturbance component (5), and its outer edge is fixedly connected to the upper chamber (31) by bolts. A bearing (55) is provided at the center of the inner ring. The outer circumference of the bearing (55) is fixedly connected to the outer edge by several connecting rods (56). The bearing (55) is placed below the sleeve (51). The rotating shaft (53) is installed inside the bearing (55).

7. A staggered flow filtration test device according to claim 6, wherein: A support plate (33) for supporting the membrane (4) is provided between the upper chamber (31) and the lower chamber (32). The periphery of the support plate (33) is fixedly connected to the inner wall of the filter (3). Several permeate channels are opened on the support plate (33). A permeate outlet (321) is provided in the lower chamber (32). The permeate outlet (321) is connected to the collector through the permeate tube (6).

8. The staggered flow filtration test device of claim 7, wherein: The material tank (1) has a material tank inlet at the top and a material tank outlet at the bottom. The material tank outlet is connected to the input end of the water pump (2), and the output end of the water pump (2) is connected to the filter tank inlet (311). The material tank (1) also has a return port at the top, which is connected to the filter tank outlet (312). A thermometer is installed on the inner wall of the upper part of the material tank (1).

9. The staggered flow filtration test device of claim 8, wherein: The pipeline connecting the input end of the water pump (2) to the feed inlet (311) of the filter tank is a feed pipe, and a feed regulating valve (7) is installed on the feed pipe; the pipeline connecting the discharge outlet (312) of the filter tank to the return outlet is a interception pipe, and an interception regulating valve (8) is installed on the interception pipe. A pressure gauge (9) is installed on the interception pipe connecting the interception regulating valve (8) and the discharge outlet (312) of the filter tank.

10. The staggered flow filtration test device of claim 9, wherein: Multiple filter tanks (3) are arranged in parallel to form a filter tank (3) group; the feed pipe is provided with several feed branches connected to the feed inlet (311) of each filter tank, and the feed regulating valve (7) is installed on each feed branch; the interception pipe is provided with several interception branches connected to the discharge outlet (312) of each filter tank, and the interception regulating valve (8) is installed on each interception regulating valve (8); each interception regulating valve (8) is provided with a pressure gauge (9) between it and the discharge outlet (312) of the filter tank connected to it, and the pressure gauge (9) is installed on the interception branch adjacent to it.

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