A laboratory-grade ceramic membrane pressure filtration device

Abstract

This invention discloses a laboratory-grade ceramic membrane pressure filtration device, comprising a pressure ceramic membrane filtration unit, a pressure pump, a feed container, a valve, and a dialysate container. This invention uses an inorganic ceramic membrane as the filter medium, which is resistant to acids and alkalis, resistant to organic solvents, has a wide range of applications, high strength, and high operating pressure. It maintains high membrane integrity during installation, disassembly, and filtration, and offers high operating flux and high recovery rate. It can withstand both high-pressure steam sterilization and chemical sterilization. The sealing method is simpler than that of tubular ceramic membranes, and the dead volume is significantly smaller, requiring relatively less feed solution, making it suitable for laboratory operating environments.

Description

Technical Field

[0001] This invention belongs to the technical field of laboratory membrane filtration equipment, specifically relating to a laboratory-grade ceramic membrane pressure filtration device. Background Technology

[0002] Membrane filtration technology is indispensable in large-scale industrial applications for treating liquids and gases, and is an important method for achieving green production in industrial manufacturing. Currently, the membranes used in membrane filtration are mainly divided into two categories: organic membranes and inorganic membranes, which can be further subdivided according to different specific materials. Organic membranes are currently the most widely used in the market, but with the development of inorganic membrane technology, especially with the maturity of ceramic membrane technology, ceramic membranes are being widely used in industrial production.

[0003] In existing technologies, filter membranes used in laboratory settings are primarily made of organic membrane materials. Due to their flexible nature, organic membrane materials are easily cut to fit the shape and structure of the equipment, allowing for quick and easy fabrication into various shapes to adapt to different filters and form a good seal. However, organic membrane materials used in laboratory settings suffer from the following insurmountable drawbacks:

[0004] 1. Organic membrane materials have low strength, and the operating pressure cannot be too high, making them prone to damage during installation.

[0005] 2. The inherent material properties of organic membranes mean they are not resistant to high temperatures, strong acids and alkalis, or organic solvents. Therefore, membrane selection must be based on the actual feed solution. If users do not have a thorough understanding of the membrane material or the properties of the feed solution, experimental failures are often caused by incorrect material selection.

[0006] 3. The laboratory filter membrane has a low flux. If a large amount of liquid needs to be filtered, the filter membrane needs to be replaced. During the replacement process, the membrane layer is easily damaged, leading to dialysis fluid contamination.

[0007] 4. For feed solutions employing filtration sterilization methods, steam sterilization is often required to sterilize the membrane material. However, existing organic membrane sterilization methods typically involve manufacturer sterilization (gamma ray sterilization) followed by easy-tear paper sealing before direct use. This method makes the membrane susceptible to contamination from the external environment during transportation or storage, potentially leading to membrane failure.

[0008] 5. The integrity of the membrane before and after filtration is very important in the filtration and sterilization process. However, organic membranes have relatively low strength. During filtration, as the pollution worsens and the operating pressure increases, the membrane may be damaged, and the filtration and sterilization effect may not be achieved.

[0009] 6. Organic membranes are mostly disposable products, rarely reused, and reuse is quite difficult.

[0010] To overcome these shortcomings, researchers began considering replacing organic membrane materials with inorganic ceramic membranes. Inorganic ceramic membranes can be categorized into tubular and planar ceramic membranes based on their shape; both types are already in large-scale industrial production. However, for laboratory settings, the shapes of existing tubular and planar ceramic membranes are unsuitable for miniaturized equipment. They require end-sealing with adhesives and then sealing with a sealing ring to the shell for filtration, making installation overly cumbersome. Furthermore, tubular and planar ceramic membranes have a large dead volume within their cavities, resulting in a requirement for large quantities of feed solution for filtration but low throughput. Summary of the Invention

[0011] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a laboratory-grade ceramic membrane pressure filtration device.

[0012] Another object of the present invention is to provide a pressure-type ceramic membrane filtration device.

[0013] The technical solution of the present invention is as follows:

[0014] A laboratory-grade ceramic membrane pressure filtration device includes a pressure ceramic membrane filtration unit, a pressure pump, a feed container, a valve, and a dialysate container.

[0015] A pressure-type ceramic membrane filtration device includes a base, a ceramic membrane sheet, an annular support pad, an inner cover, and an annular pressure cap.

[0016] The base has a base plate, the edge of which extends upward to form a base sidewall, and a dialysate through-hole is provided in the middle of the base plate.

[0017] The ceramic membrane sheet, with a flatness of less than 0.05 mm, comprises a separation membrane layer, a transition layer, and a support layer that are sequentially connected to each other.

[0018] The annular support pad is adapted to the shape and size of the ceramic diaphragm, and has a number of guide ribs that extend toward the center at equal intervals along its edge and whose free ends do not contact each other.

[0019] The inner cover is adapted to the external dimensions of the aforementioned ceramic membrane sheet. Its outer wall features a first-step structure, wider at the bottom and narrower at the top. A sealing ring mounting groove is located at its lower end, housing a sealing ring. The inner cover has a through-feed channel and a concentrate channel, with a spiral flow channel on its bottom surface. The feed channel and concentrate channel are connected via this spiral flow channel. The spiral flow channel contains several smoothly curved protrusions, the height of which is less than the depth of the spiral flow channel.

[0020] The ring-shaped cap has an inner wall with a first stepped structure that is larger at the top and smaller at the bottom, which is adapted to the outer wall of the ring-shaped inner cap.

[0021] The ceramic membrane is placed on the substrate of the base via an annular support pad, forming a dialysate chamber with the substrate and the side wall of the base. The support layer of the ceramic membrane faces the substrate, and the guide ribs of the annular support pad extend toward the through hole of the substrate to guide the fluid in the dialysate chamber to the through hole. The inner cover is placed on the separation membrane layer of the ceramic membrane, and its bottom surface is in close contact with the separation membrane layer. The second stepped structure of the annular pressure cap is pressed and adapted to the first stepped structure of the inner cover so that the inner cover is sealed and pressed against the side wall of the base and the ceramic membrane through the sealing ring.

[0022] The dialysate container is connected to the through hole of the substrate, the feed container is connected to the feed channel of the inner cover through a pressure pump, and the concentrate channel of the inner cover is connected to the feed container through a valve.

[0023] In a preferred embodiment of the present invention, the base sidewall is provided with a plurality of threaded holes evenly spaced along its periphery, and the annular cover is provided with a plurality of through holes evenly spaced along its periphery, the number of which is the same as the plurality of threaded holes. A plurality of clamping bolts pass through the plurality of through holes and are threadedly connected to the plurality of threaded holes so that the second stepped structure of the annular cover is clamped and adapted to the first stepped structure of the annular inner cover.

[0024] In a preferred embodiment of the present invention, the base is provided with a plurality of support rods.

[0025] In a preferred embodiment of the present invention, the material of the annular support pad is fluororubber, silicone, EPDM, nitrile, or PTFE-coated fluororubber.

[0026] In a preferred embodiment of the present invention, the sealing ring is made of fluororubber, silicone, EPDM, nitrile, or PTFE-coated fluororubber.

[0027] Another technical solution of the present invention is as follows:

[0028] A pressure-type ceramic membrane filtration device includes a base, a ceramic membrane sheet, an annular support pad, an inner cover, and an annular pressure cap.

[0029] The base has a base plate, the edge of which extends upward to form a base sidewall, and a dialysate through-hole is provided in the middle of the base plate.

[0030] The ceramic membrane sheet, with a flatness of less than 0.05 mm, comprises a separation membrane layer, a transition layer, and a support layer that are sequentially connected to each other.

[0031] The annular support pad is adapted to the shape and size of the ceramic diaphragm, and has a number of guide ribs that extend toward the center at equal intervals along its edge and whose free ends do not contact each other.

[0032] The inner cover is adapted to the external dimensions of the aforementioned ceramic membrane sheet. Its outer wall features a first-step structure, wider at the bottom and narrower at the top. A sealing ring mounting groove is located at its lower end, housing a sealing ring. The inner cover has a through-feed channel and a concentrate channel, with a spiral flow channel on its bottom surface. The feed channel and concentrate channel are connected via this spiral flow channel. The spiral flow channel contains several smoothly curved protrusions, the height of which is less than the depth of the spiral flow channel.

[0033] The ring-shaped cap has an inner wall with a first stepped structure that is larger at the top and smaller at the bottom, which is adapted to the outer wall of the ring-shaped inner cap.

[0034] The ceramic membrane is placed on the substrate of the base via an annular support pad, forming a dialysate chamber with the substrate and the side wall of the base. The support layer of the ceramic membrane faces the substrate, and the guide ribs of the annular support pad extend towards the through hole of the substrate to guide the fluid in the dialysate chamber to the through hole. The inner cover is placed on the separation membrane layer of the ceramic membrane, and its bottom surface is in close contact with the separation membrane layer. The second stepped structure of the annular pressure cap is pressed and adapted to the first stepped structure of the inner cover so that the inner cover is sealed and pressed against the side wall of the base and the ceramic membrane via sealing rings.

[0035] In a preferred embodiment of the present invention, the base sidewall is provided with a plurality of threaded holes evenly spaced along its periphery, and the annular cover is provided with a plurality of through holes evenly spaced along its periphery, the number of which is the same as the plurality of threaded holes. A plurality of clamping bolts pass through the plurality of through holes and are threadedly connected to the plurality of threaded holes so that the second stepped structure of the annular cover is clamped and adapted to the first stepped structure of the annular inner cover.

[0036] In a preferred embodiment of the present invention, the base is provided with a plurality of support rods.

[0037] In a preferred embodiment of the present invention, the depth of the spiral channel is 1-5 mm, the width is 5-10 mm, and the height of the smooth curved protrusion is 0.8-3 mm.

[0038] In a preferred embodiment of the present invention, the clamping bolt is a Torx bolt, an external hex bolt, or an internal hex bolt.

[0039] The beneficial effects of this invention are:

[0040] 1. This invention uses an inorganic ceramic membrane as the filter medium, which is resistant to acids and alkalis and organic solvents, and has a wide range of applications.

[0041] 2. This invention uses an inorganic ceramic membrane as the filter medium, which has high strength and high operating pressure, and can maintain a high degree of membrane integrity during installation, disassembly, and filtration. Furthermore, under the same membrane area and feed conditions, the flux of this inorganic ceramic filter membrane is 2-5 times higher than that of an organic filter membrane.

[0042] 3. This invention can withstand both high-pressure steam sterilization and chemical sterilization.

[0043] 4. The present invention uses an inorganic ceramic membrane with a specific structure as the filter medium, which does not require adhesive sealing. It can be directly installed for filtration. The sealing method is simpler than that of tubular ceramic membranes, and the dead volume is significantly smaller than that of tubular ceramic membranes. The required liquid is relatively less, which is suitable for laboratory operating environments.

[0044] 5. This invention utilizes the acid and alkali resistance and high temperature resistance of inorganic ceramic membranes, resulting in high operating throughput, high recovery rate, and slow fouling rate. The membranes can be cleaned with acids and alkalis before reuse. If the fouling is too severe, they can be directly recycled at high temperature. If they cannot be reused, the waste filter membranes are relatively environmentally friendly. Attached Figure Description

[0045] Figure 1 This is a structural cross-sectional view of the pressure-type ceramic membrane filtration device in Embodiment 1 of the present invention.

[0046] Figure 2 This is a three-dimensional structural diagram of the annular support pad in Embodiment 1 of the present invention.

[0047] Figure 3 This is a three-dimensional structural diagram of the inner cover in Embodiment 1 of the present invention.

[0048] Figure 4 This is a three-dimensional structural diagram of the inner cover in Comparative Example 1 of the present invention.

[0049] Figure 5 This is a schematic diagram of the laboratory-grade ceramic membrane pressure filtration device in Embodiment 2 and Comparative Example 2 of the present invention.

[0050] Figure 6 This is a schematic diagram of the organic membrane filter used in Comparative Example 3 of the present invention.

[0051] Figure 7 This is a schematic diagram of the tubular ceramic membrane filtration system used in Comparative Example 4 of the present invention. Detailed Implementation

[0052] The technical solution of the present invention will be further explained and described below with reference to specific embodiments and accompanying drawings.

[0053] Example 1

[0054] like Figure 1 As shown, a pressure-type ceramic membrane filtration device includes a base 1, a ceramic membrane sheet 2, an annular support pad 3, an inner cover 4, and an annular pressure cap 5.

[0055] The base 1 has a base plate 10, the edge of which extends upward to form a base side wall 11, and a dialysate through hole 101 is provided in the middle of the base plate 10. The base 1 is provided with a plurality of equally spaced support rods 102 (in this embodiment, there are three support rods, and each support rod 102 is a thin round rod bent into shape, one end of which is threaded to the base 11, and the other end is fitted with a rubber pad, so that the entire negative pressure ceramic membrane filtration device can stand stably).

[0056] The ceramic membrane 2 has a flatness of less than 0.05 mm, a diameter of no more than 100 mm, and a thickness of no more than 3.0 mm (flexural strength of 23-27 MPa, filtration accuracy of approximately 0.2 μm, and a pure water flux of 4300-5800 LMH). It consists of a separation membrane layer and a support layer connected sequentially to each other.

[0057] like Figure 2 As shown, the annular support pad 3 has a thickness of at least 2.0 mm, is adapted to the external dimensions of the ceramic membrane 2, and has a plurality of (at least five) guide ribs 31 that extend toward the center of the annular support pad 3 at equal intervals along its edge and whose free ends do not contact each other; the material of the annular support pad 3 is fluororubber, silicone, EPDM, nitrile, or polytetrafluoroethylene-coated fluororubber.

[0058] like Figure 3 As shown, the inner cover 4 is adapted to the external dimensions of the ceramic membrane 2. Its outer wall has a first stepped structure 40, smaller at the top and larger at the bottom, and a sealing ring mounting groove 41 at its lower end. A sealing ring 42 is installed in the sealing ring mounting groove 41. The sealing ring 42 is made of fluororubber, silicone, EPDM, nitrile, or PTFE-coated fluororubber. The inner cover 4 has a through-feed channel 43 and a concentrate channel 44. Its lower surface has a spiral flow channel 45, which connects the feed channel 43 and the concentrate channel 44. The spiral flow channel 45 has a depth of 1-5 mm and a width of 5-10 mm. Figure 3 As shown, the spiral flow channel 45 is provided with several smoothly curved protrusions 450. The height of the smoothly curved protrusions 450 is lower than the depth of the spiral flow channel 45. Preferably, the height of the smoothly curved protrusions 450 is 0.8-3mm. The highest point of the smooth curved surface is 1-3mm lower than the sidewall of the spiral flow channel 45, and the highest point of the smooth curved surface is the narrowest channel for the liquid. This design facilitates turbulent flow of the liquid within the spiral flow channel 45, effectively reducing the problem of contaminant accumulation.

[0059] The annular pressure cap 5 has an inner wall with a second stepped structure 50 that is larger at the top and smaller at the bottom, which is adapted to the outer wall of the annular inner cap 4.

[0060] The ceramic membrane 2 is placed on the substrate 10 of the base 1 via the annular support pad 3, forming a dialysate chamber with the substrate 10 and the side wall 11 of the base. The support layer of the ceramic membrane 2 faces the substrate 10. The guide ribs 31 of the annular support pad 3 extend towards the through hole of the substrate 10 to guide the fluid in the dialysate chamber to the dialysate through hole 101. The inner cover 4 is placed on the separation membrane layer of the ceramic membrane 2, and its bottom surface is in close contact with the separation membrane layer. The second stepped structure 50 of the annular pressure cap 5 is pressed and matched with the first stepped structure 40 of the inner cover 4 so that the inner cover 4 is sealed and pressed against the side wall 11 of the base and the ceramic membrane 2 respectively by the sealing ring 42 (the deformation of the sealing ring 42 is 10-30%, and the deformation is controlled by the extrusion pressure on the inner cover 4).

[0061] Specifically, the base sidewall 11 has a plurality of threaded holes 110 evenly spaced along its periphery, and the annular cover 5 has a plurality of through holes 52 evenly spaced along its periphery, the same number as the plurality of threaded holes 110. A plurality of clamping bolts 6 (plaster bolts, hexagonal bolts or socket head cap bolts) pass through the plurality of through holes 52 and are threadedly connected to the plurality of threaded holes 110 so that the second stepped structure 50 of the annular cover 5 is clamped and adapted to the first stepped structure 40 of the annular inner cover 4 (when the clamping bolts 6 are not tightened, the lower end of the annular cover 5 does not directly contact the upper end of the base sidewall 11, leaving a certain gap; after the clamping bolts 6 are tightened, the gap is only reduced rather than disappeared).

[0062] The method for preparing the ceramic membrane 2 in this embodiment includes:

[0063] 1) Alumina powder with an average particle size of 8μm was mixed with 2L of deionized water at a volume ratio of 70%, and 1mL of 65% nitric acid was added. After thorough stirring, the pH value of the solution was measured to be 4.0. NH4NO3 was added at an ion concentration of 0.1mol / L. The mixture was ball-milled for 0.5h to prepare a slurry. The slurry was heated in a 60℃ water bath for 15min and then sequentially poured into multiple cylindrical molds with an opening at the top, each with a diameter of 95mm and a height of 3.0mm. The molds were made of PMMA. The molds were removed after being placed in the air for 2h. The green body was dried in a 65℃ oven for 24h and then sintered: the temperature was first raised to 1200℃ at a rate of 2℃ / min and held for 2h, and then raised to 1550℃ at a rate of 1℃ / min and held for 2h to obtain the support layer.

[0064] 2) Weigh 100 parts of alumina powder with an average particle size of 0.5 μm, 5 parts of polyvinyl alcohol with a molecular weight of 2000, and 15 parts of hydroxypropyl methylcellulose with a viscosity of 4000 cps. Then add deionized water and place the mixture in a planetary ball mill. Use alumina balls as the grinding medium and grind at high speed for 1 hour to obtain a coating liquid with a solid content of 15%. Seal one side of the support layer with waterproof double-sided tape, then pull one side of the double-sided tape and immerse the support layer in the coating liquid. After immersion for 1 minute, remove the support layer and lay it flat for 5 hours. Slowly heat the temperature to 100℃ and bake for 3 hours. Then peel off the double-sided tape and sinter: heat the temperature to 1300℃ at a rate of 2℃ / min and hold for 2 hours to prepare the separation membrane layer and obtain the ceramic membrane sheet 2.

[0065] Comparative Example 1

[0066] It is basically the same as Example 1, except that: Figure 4 As shown, the spiral flow channel 45 does not have several smooth curved protrusions 450.

[0067] Example 2

[0068] like Figure 5 As shown, a laboratory-grade ceramic membrane pressure filtration device includes a pressure ceramic membrane filtration device as described in Example 1, a pressure pump 71, a feed container 72, a valve 73, and a dialysate container 74.

[0069] Specifically, the dialysate container 74 is connected to the dialysate through-hole 101 of the substrate 10 via a hose, and the feed container 72 is connected to the feed channel 43 of the inner cover 4 via a pressure pump 71 and a hose. The concentrate channel 44 of the inner cover 4 is connected to the feed container 72 via a valve 73 and a hose. The pressure pump 71 is preferably a peristaltic pump or a magnetic pump, with a flow rate of 100 mL / min or higher and a head of 10-40 m. The valve 73 can be a ball valve or a needle valve, preferably a needle valve, which allows for precise pressure control. The pressure of the entire laboratory-grade ceramic membrane pressure filtration system does not exceed 6.0 bar.

[0070] For applications involving large feed volumes (>300mL), simple feed preparation, easy membrane contamination, or large permeate volumes, the laboratory-grade ceramic membrane pressure filtration device of this embodiment can be used. This filtration method requires the formation of backflow in the spiral flow channel 45 within the tubing 3 and inner cover 4 to reduce membrane fouling. This is because the device requires a minimum feed volume for circulation (minimum 100mL of feed). This filtration method is not suitable for applications with insufficient feed volume. Furthermore, the device can mitigate membrane fouling by increasing the filtration pressure and membrane surface flow rate, which is beneficial for generating more dialysate.

[0071] Comparative Example 2

[0072] Basically the same as in Example 3, such as Figure 5 As shown, a laboratory-grade ceramic membrane pressure filtration device includes a pair of pressure ceramic membrane filtration devices as shown in Example 1, a pressure pump 71, a feed container 72, a valve 73, and a dialysate container 74.

[0073] Comparative Example 3

[0074] In this comparative example 3, the following is used: Figure 6 The organic membrane filter shown places the membrane between the sand filter head and the filter cup, and connects the filter to a circulating water vacuum pump for filtration. This equipment offers simple and convenient membrane installation and assembly. However, organic membranes are prone to fouling during operation, requiring replacement. While replacement is easy, their low strength makes them susceptible to creases and damage during replacement. Furthermore, disassembling the filter head and filter bottle after filtration is difficult due to the vacuum. For sterilization filtration, the most crucial step is pressure- and high-temperature sterilization of the membrane and equipment. Organic membranes require sterilization before leaving the factory (not pressure steam sterilization, but typically radiation or chemical sterilization), leading to disposable filters and pre-sterilized filters. Therefore, conventional organic membranes cannot be used for sterilization filtration in practice, and their application requires ensuring the manufacturer's sterilization effectiveness and preventing contamination during transportation. In sterile filtration, the integrity of the filter membrane needs to be tested after the experiment, usually through immersion pressure or pressure holding tests. However, for organic filter membranes, the sealing is too simple and the strength is low, making it difficult to test the membrane's integrity. Furthermore, in organic solvent filtration applications, it is crucial to select a suitable filter membrane material; otherwise, the membrane may dissolve in the organic solvent.

[0075] Comparative Example 4

[0076] Comparative Example 4 adopts the following... Figure 7 The tubular ceramic membrane filtration system shown is used for filtration, but this equipment is generally used for industrial-scale liquid experiments. The flow channels of the tubular ceramic membrane and the space between the ceramic membrane and the external cavity are relatively large. At the same time, this equipment requires a large flow rate; therefore, the minimum liquid volume required for the circulation of this equipment is no less than 2L. However, for laboratory-level filtration, it is difficult to prepare large quantities of experimental liquid, making this equipment unusable. Furthermore, for sterilization filtration, the equipment is too large to be placed in an autoclave for sterilization, and the pump cannot be sterilized.

[0077] The feature comparison of Embodiment 2 and Comparative Examples 2 to 4 of the present invention is shown in Table 1 below:

[0078] Table 1

[0079]

[0080]

[0081] To verify the sterilization filtration performance, a microbial challenge method was used. This method involved filtering a culture medium containing quantitative indicator bacteria to assess the sterilization filter's filtration and sterilization capabilities. In this experiment, LB liquid medium was used to culture the indicator bacterium *Aureobasidium degeneratum* (ATCC 19146), which has an average particle size of 0.3 μm and cannot permeate a 0.22 μm filter membrane. Furthermore, a bacterial concentration of 10-1 was required. 7 CFU per square centimeter of filter membrane area. Incubate the culture medium at 30-37℃ for 18-24 hours to achieve the required bacterial concentration.

[0082] For Comparative Example 3, a cellulose acetate filter membrane with a diameter of 50 mm and a pore size of 0.22 μm was selected, and the above-mentioned liquid was then filtered.

[0083] For Comparative Example 4, a tubular ceramic membrane with a length of 25 cm and a pore size of 200 nm was used to filter the above-mentioned liquid.

[0084] For Example 2 and Comparative Example 2, an inorganic ceramic filter membrane (circular) was selected as the ceramic membrane sheet 2, with a diameter of 91 mm and a membrane area of ​​65 cm². 2 With a pore size of 200nm, it is used for filtration.

[0085] The filtered dialysate was subjected to plate count.

[0086] The experimental results are shown in Table 2 below:

[0087]

[0088]

[0089] The experimental data above indicate that because the cellulose acetate membrane in Comparative Example 3 is not heat-resistant and the accessory pump in Comparative Example 2 cannot be autoclaved, bacteria were present in the dialysate. In contrast, both Example 2 and Comparative Example 2 underwent autoclaving, so no colonies were detected in the dialysate. Comparing Comparative Example 3 with Examples 2 and 2 reveals that the operating flux of the organic filter membrane is lower than that of the inorganic ceramic filter membrane. Under the same conditions, both inorganic and organic filter membranes produce the same filtrate, but the inorganic ceramic membrane takes less time to filter. In Comparative Example 4, although the tubular ceramic membrane has the shortest permeation time, its large feed rate and low recovery rate limit its application in laboratory-level filtration. Examples 2 and 2 show that Example 2 has a higher operating flux and higher recovery rate, mainly because the smooth, curved protrusions promote turbulent flow of the feed liquid within the spiral channel, preventing contaminant accumulation and enhancing the membrane's antifouling ability, making it advantageous for laboratory-level filtration.

[0090] Because organic filter membranes are disposable, they cannot be cleaned and restored. In Comparative Example 4, the tubular ceramic membrane had a pressure differential of 1.5 bar and an initial flux of approximately 2500 LMH. After filtration, it was cleaned with 1% alkaline solution at 40-60°C, and the flux was restored to over 90%. In Example 2 and Comparative Example 2, the ceramic membrane 2 had a pressure differential of 1.5 bar and an initial flux of approximately 4500 LMH. After hand washing and chemical cleaning (1% alkaline solution at 40-60°C), the flux could be restored to over 90%. This indicates that the ceramic membrane 2, like the tubular ceramic membrane, can be chemically cleaned, regenerated, and reused.

[0091] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A laboratory-grade ceramic membrane pressure filtration device, characterized in that: It includes a pressure ceramic membrane filtration device, a pressure pump, a feed container, a valve, and a dialysate container; A pressure-type ceramic membrane filtration device includes a base, a ceramic membrane sheet, an annular support pad, an inner cover, and an annular pressure cap. The base has a base plate, the edge of which extends upward to form a base sidewall, and a dialysate through-hole is provided in the middle of the base plate. The ceramic membrane sheet, with a flatness of less than 0.05 mm, comprises a separation membrane layer, a transition layer, and a support layer that are sequentially connected to each other. The annular support pad is adapted to the shape and size of the ceramic diaphragm, and has a number of guide ribs that extend toward the center at equal intervals along its edge and whose free ends do not contact each other. The inner cover is adapted to the external dimensions of the aforementioned ceramic membrane sheet. Its outer wall features a first-step structure, wider at the bottom and narrower at the top. A sealing ring mounting groove is located at its lower end, housing a sealing ring. The inner cover has a through-feed channel and a concentrate channel, with a spiral flow channel on its bottom surface. The feed channel and concentrate channel are connected via this spiral flow channel. The spiral flow channel contains several smoothly curved protrusions, the height of which is less than the depth of the spiral flow channel. The ring-shaped cap has an inner wall with a first stepped structure that is larger at the top and smaller at the bottom, which is adapted to the outer wall of the ring-shaped inner cap. The ceramic membrane is placed on the substrate of the base via an annular support pad, forming a dialysate chamber with the substrate and the side wall of the base. The support layer of the ceramic membrane faces the substrate, and the guide ribs of the annular support pad extend toward the through hole of the substrate to guide the fluid in the dialysate chamber to the through hole. The inner cover is placed on the separation membrane layer of the ceramic membrane, and its bottom surface is in close contact with the separation membrane layer. The second stepped structure of the annular pressure cap is pressed and adapted to the first stepped structure of the inner cover so that the inner cover is sealed and pressed against the side wall of the base and the ceramic membrane through the sealing ring. The dialysate container is connected to the through hole of the substrate, the feed container is connected to the feed channel of the inner cover through a pressure pump, and the concentrate channel of the inner cover is connected to the feed container through a valve.

2. The laboratory-grade ceramic membrane pressure filtration device as described in claim 1, characterized in that: The base sidewall is provided with a plurality of threaded holes evenly spaced along its periphery, and the annular cover is provided with a plurality of through holes evenly spaced along its periphery, the number of which is the same as the plurality of threaded holes. A plurality of clamping bolts pass through the plurality of through holes and are threadedly connected to the plurality of threaded holes so that the second stepped structure of the annular cover is clamped and adapted to the first stepped structure of the annular inner cover.

3. The laboratory-grade ceramic membrane pressure filtration device as described in claim 1, characterized in that: The base is provided with several support rods.

4. The laboratory-grade ceramic membrane pressure filtration device as described in claim 1, characterized in that: The annular support pad is made of fluororubber, silicone, EPDM, nitrile, or PTFE-coated fluororubber.

5. The laboratory-grade ceramic membrane pressure filtration device as described in claim 1, characterized in that: The sealing ring is made of fluororubber, silicone, EPDM, nitrile, or PTFE-coated fluororubber.

6. A pressure-type ceramic membrane filtration device, characterized in that: It includes a base, a ceramic diaphragm, an annular support pad, an inner cover, and an annular pressure cap. The base has a base plate, the edge of which extends upward to form a base sidewall, and a dialysate through-hole is provided in the middle of the base plate. The ceramic membrane sheet, with a flatness of less than 0.05 mm, comprises a separation membrane layer, a transition layer, and a support layer that are sequentially connected to each other. The annular support pad is adapted to the shape and size of the ceramic diaphragm, and has a number of guide ribs that extend toward the center at equal intervals along its edge and whose free ends do not contact each other. The inner cover is adapted to the external dimensions of the aforementioned ceramic membrane sheet. Its outer wall features a first-step structure, wider at the bottom and narrower at the top. A sealing ring mounting groove is located at its lower end, housing a sealing ring. The inner cover has a through-feed channel and a concentrate channel, with a spiral flow channel on its bottom surface. The feed channel and concentrate channel are connected via this spiral flow channel. The spiral flow channel contains several smoothly curved protrusions, the height of which is less than the depth of the spiral flow channel. The ring-shaped cap has an inner wall with a first stepped structure that is larger at the top and smaller at the bottom, which is adapted to the outer wall of the ring-shaped inner cap. The ceramic membrane is placed on the substrate of the base via an annular support pad, forming a dialysate chamber with the substrate and the side wall of the base. The support layer of the ceramic membrane faces the substrate, and the guide ribs of the annular support pad extend towards the through hole of the substrate to guide the fluid in the dialysate chamber to the through hole. The inner cover is placed on the separation membrane layer of the ceramic membrane, and its bottom surface is in close contact with the separation membrane layer. The second stepped structure of the annular pressure cap is pressed and adapted to the first stepped structure of the inner cover so that the inner cover is sealed and pressed against the side wall of the base and the ceramic membrane via sealing rings.

7. A pressure-type ceramic membrane filtration device as described in claim 6, characterized in that: The base sidewall is provided with a plurality of threaded holes evenly spaced along its periphery, and the annular cover is provided with a plurality of through holes evenly spaced along its periphery, the number of which is the same as the plurality of threaded holes. A plurality of clamping bolts pass through the plurality of through holes and are threadedly connected to the plurality of threaded holes so that the second stepped structure of the annular cover is clamped and adapted to the first stepped structure of the annular inner cover.

8. A pressure-type ceramic membrane filtration device as described in claim 6, characterized in that: The base is provided with several support rods.

9. A pressure-type ceramic membrane filtration device as described in claim 6, characterized in that: The spiral channel has a depth of 1-5mm and a width of 5-10mm, and the smooth curved protrusion has a height of 0.8-3mm.

10. A pressure-type ceramic membrane filtration device as described in claim 7, characterized in that: The clamping bolt is a Torx bolt, an external hex bolt, or an internal hex bolt.

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