Filter membrane structure of spherical graphite reverse osmosis device

Abstract

The utility model provides a kind of filtering membrane structure of spherical graphite reverse osmosis device belongs to spherical graphite reverse osmosis device technical field, the filtering membrane structure of this spherical graphite reverse osmosis device includes: spherical shell, filter membrane component, support framework, water inlet pipeline, water outlet pipeline and sealing ring;The spherical shell is made of stainless steel material, the surface of spherical shell is equipped with water inlet and water outlet, water inlet is located in the upper hemispherical surface of spherical shell, and water outlet is located in the lower hemispherical surface of spherical shell;The filter membrane component is arranged inside spherical shell, and the filter membrane component includes graphite filter membrane and membrane fixed frame, the graphite filter membrane is spherical and concentrically arranged with the inner surface of spherical shell;It can solve the technical problems that the filtering membrane structure of spherical reverse osmosis device in the prior art has uneven stress on membrane material, insufficient support strength, unreasonable fluid distribution, low filtration efficiency and short membrane life.

Description

Technical Field

[0001] This utility model belongs to the technical field of spherical graphite reverse osmosis devices, specifically, it relates to a filter membrane structure for a spherical graphite reverse osmosis device. Background Technology

[0002] Reverse osmosis technology, as an important membrane separation technology, is widely used in seawater desalination, industrial wastewater treatment, and drinking water purification. Traditional reverse osmosis units mostly adopt flat or tubular structures. Although the technology is relatively mature, it suffers from problems such as large footprint, uneven fluid distribution, and severe membrane fouling. In recent years, spherical reverse osmosis units have attracted attention due to their compact structure and strong pressure resistance. However, existing spherical reverse osmosis units still have shortcomings in the design of the filter membrane support structure. Existing spherical reverse osmosis units typically use a simple radial support structure. This structure cannot provide uniform support force for the filter membrane, which can easily lead to membrane material deformation or even damage under high-pressure operating conditions. At the same time, existing support structure designs often neglect the impact on fluid flow. Simple support ribs are prone to creating dead zones and eddies, reducing mass transfer efficiency. Regarding membrane materials, graphite is considered an ideal material for preparing high-performance reverse osmosis membranes due to its excellent chemical stability, good thermal conductivity, and unique separation characteristics. However, how to rationally configure graphite filter membranes in a spherical structure to fully utilize its performance advantages remains a technical challenge. Existing technologies mainly address membrane support issues by increasing the number of support ribs or improving their strength. However, these methods often come at the cost of increased flow resistance and reduced effective filtration area, making it difficult to achieve ideal overall performance. Utility Model Content

[0003] In view of this, the present invention provides a filtration membrane structure for a spherical graphite reverse osmosis device, which can solve the technical problems of uneven stress on the membrane material, insufficient support strength, and unreasonable fluid distribution in the filtration membrane structure of existing spherical reverse osmosis devices, resulting in low filtration efficiency and short membrane life.

[0004] This utility model is implemented as follows: This utility model provides a filter membrane structure for a spherical graphite reverse osmosis device, comprising: a spherical shell, a filter membrane assembly, a support frame, an inlet pipe, an outlet pipe, and a sealing ring; the spherical shell is made of stainless steel, and an inlet and an outlet are provided on its surface, with the inlet located on the upper hemisphere and the outlet located on the lower hemisphere; the filter membrane assembly is disposed inside the spherical shell, and includes a graphite filter membrane and a membrane fixing frame, the graphite filter membrane being spherical in shape and concentrically arranged with the inner surface of the spherical shell, and the membrane fixing frame... The frame is fixedly connected to the inner wall of the spherical shell by multiple radially distributed connecting rods; the support skeleton is located inside the graphite filter membrane and is made of polytetrafluoroethylene material. The support skeleton includes a central support ball and multiple radially distributed support ribs. The central support ball is located at the geometric center of the spherical shell. One end of the support rib is fixedly connected to the central support ball, and the other end contacts and supports the inner surface of the graphite filter membrane; the inlet pipe and outlet pipe are threadedly connected to the inlet and outlet respectively, and sealing rings are set at the connection between the inlet pipe and the inlet and the outlet pipe and the outlet.

[0005] The technical advantages of the filtration membrane structure of the spherical graphite reverse osmosis device provided by this utility model are as follows: The concentric configuration of the spherical shell and the filtration membrane assembly achieves uniform distribution of the filtration medium and symmetrical flow of the fluid. The spherical structure has the characteristic of having the smallest surface area to volume ratio, reducing material usage and manufacturing costs. Simultaneously, the spherical structure has strong pressure resistance and can withstand high-pressure reverse osmosis operating conditions. The supporting frame prevents the filtration membrane from deforming under high pressure differential, ensuring the stability of the filtration effect. The separate design of the inlet and outlet pipes avoids cross-contamination between raw water and purified water. The use of sealing rings ensures the sealing performance of the system. The overall structure is compact and reasonable, and operation and maintenance are convenient.

[0006] Based on the above technical solution, the filter membrane structure of the spherical graphite reverse osmosis device of this utility model can be further improved as follows: The membrane fixing frame has a ring structure, and the outer diameter of the membrane fixing frame matches the inner diameter of the spherical shell. The membrane fixing frame is connected to the inner wall of the spherical shell by at least 6 evenly distributed fixing bolts. The fixing bolts pass through the preset holes on the membrane fixing frame, the bolt heads fit against the inner surface of the membrane fixing frame, and the bolt tails engage with the threaded holes on the inner wall of the spherical shell.

[0007] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the ring structure design of the membrane fixing frame enables the graphite filter membrane to be evenly stressed, avoiding membrane material damage caused by local stress concentration; the connection between the membrane fixing frame and the spherical shell is ensured by at least 6 evenly distributed fixing bolts; the design of the bolts passing through the preset holes facilitates assembly and maintenance; the structure of the bolt head fitting with the inner surface of the membrane fixing frame avoids bolt protrusion and damage to the filter membrane; the fit between the bolt tail and the threaded hole on the inner wall of the spherical shell provides sufficient connection strength; the entire fixing system has a simple and reliable structure, which is convenient for mass production and on-site installation.

[0008] Furthermore, the graphite filter membrane has a thickness of 2 mm to 5 mm, and the surface of the graphite filter membrane has a microporous structure with a micropore diameter of 0.1 μm to 0.5 μm. The graphite filter membrane is bonded and fixed to the inner circumferential surface of the membrane fixing frame by epoxy resin adhesive with a bonding width of 3 mm to 8 mm. The graphite filter membrane is bent inward in the bonding area to form a sealing edge, and the sealing edge and the membrane fixing frame form a double sealing structure.

[0009] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the 2 mm to 5 mm thickness design of the graphite filter membrane ensures sufficient structural strength while maintaining good permeability; the micropore diameter range of 0.1 micron to 0.5 micron can effectively intercept tiny pollutants such as bacteria and viruses; the use of epoxy resin adhesive ensures a firm connection between the filter membrane and the membrane fixing frame; the 3 mm to 8 mm bonding width provides ample bonding area; the bending design of the graphite filter membrane sealing edge and the double sealing structure formed by the membrane fixing frame effectively prevent the bypass seepage of raw water, improve filtration accuracy and water purification quality, and significantly enhance the sealing performance of the entire membrane system.

[0010] Furthermore, the diameter of the central support ball is 0.15 to 0.25 times the inner diameter of the spherical shell. The surface of the central support ball has multiple through holes with a diameter of 3 mm to 6 mm. The through hole axes are distributed radially. The number of support ribs is 12 to 18. The support ribs are distributed at equal angles, and the included angle between adjacent support ribs is 20 degrees to 30 degrees. The cross-sectional shape of the support ribs is T-shaped, and the web thickness of the T-shaped cross-section is 1 mm to 3 mm.

[0011] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the design of the central support ball diameter being 0.15 to 0.25 times the inner diameter of the spherical shell maximizes the filtration area while ensuring the support effect; the design of multiple through holes on the surface of the central support ball promotes fluid flow and distribution; the through hole diameter of 3 mm to 6 mm ensures flow rate while avoiding clogging; the equiangular distribution of 12 to 18 support ribs ensures the uniformity of stress on the filter membrane; the 20-30 degree included angle design of adjacent support ribs optimizes the fluid flow path; the T-shaped cross-section support rib structure provides good support strength and rigidity; and the web thickness of 1 mm to 3 mm reduces the amount of material used while ensuring strength.

[0012] Furthermore, the diameter of the spherical shell is 200 mm to 800 mm, the wall thickness of the spherical shell is 8 mm to 15 mm, and the spherical shell is composed of an upper hemisphere and a lower hemisphere connected by a flange. The flange is located at the maximum circumference of the spherical shell, and the flange faces of the upper and lower hemispheres are sealed by O-rings. The flange connection uses high-strength bolts, and the number of bolts is 16 to 24.

[0013] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the spherical shell diameter range of 200 mm to 800 mm meets the application requirements of different processing capacities; the wall thickness design of 8 mm to 15 mm ensures the pressure bearing capacity and structural safety of the shell; the flange connection structure of the upper and lower hemispherical shells facilitates the assembly and maintenance of the equipment; the design of the flange located at the maximum circumference ensures uniform stress distribution at the connection; the use of O-rings ensures the sealing performance of the flange connection; the use of 16 to 24 high-strength bolts ensures the reliability of the flange connection; and the entire shell structure has good sealing performance and mechanical strength, enabling it to operate stably in high-pressure working environments for a long time.

[0014] Furthermore, both the inlet and outlet pipes are made of stainless steel. The inner diameter of the inlet pipe is 0.08 to 0.12 times the diameter of the spherical shell, and the inner diameter of the outlet pipe is 0.6 to 0.8 times the inner diameter of the inlet pipe. The length of the inlet pipe extending into the spherical shell is 0.3 to 0.5 times the radius of the spherical shell, and the length of the outlet pipe extending into the spherical shell is 0.2 to 0.4 times the radius of the spherical shell. Both the inlet and outlet pipes are equipped with guide cones at their ends, with a cone angle of 30 to 60 degrees.

[0015] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the inlet and outlet pipes are made of stainless steel, which has good corrosion resistance and hygiene safety. The design of the inner diameter of the inlet pipe being 0.08 to 0.12 times the diameter of the spherical shell ensures sufficient inlet flow. The design of the inner diameter of the outlet pipe being 0.6 to 0.8 times the inner diameter of the inlet pipe conforms to the characteristics of filtration and flow reduction. The different extension lengths of the inlet and outlet pipes optimize the flow distribution of fluid within the spherical shell. The setting of the guide cone reduces fluid eddies and energy consumption. The cone angle design of 30 to 60 degrees ensures the flow guiding effect while avoiding excessive pressure loss. The entire pipeline system is reasonably designed with low flow resistance and low energy consumption.

[0016] Furthermore, the surface of the support rib is provided with a corrugated convex-concave structure, the peak height of the corrugations is 0.5 mm to 2 mm, the wavelength is 5 mm to 15 mm, and the corrugations extend along the length direction of the support rib.

[0017] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the corrugated uneven structure on the surface of the support rib increases the contact area between the support rib and the fluid, improving the mass transfer efficiency; the design of a wave crest height of 0.5 mm to 2 mm enhances the disturbance effect while avoiding excessive flow resistance; the wavelength design of 5 mm to 15 mm generates a suitable turbulence intensity; the extension of the corrugations along the length of the support rib ensures a uniform disturbance effect on the entire surface of the support rib; this surface structure design effectively prevents the deposition of pollutants on the surface of the support rib, improves the equipment's anti-fouling ability, extends the service life of the filter membrane, and reduces the frequency of cleaning and maintenance.

[0018] Furthermore, the surface of the central support ball is provided with a spiral groove, the groove depth of which is 1 mm to 3 mm, the groove width of which is 2 mm to 5 mm, and the spiral angle of which is 15 degrees to 45 degrees.

[0019] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the spiral groove design on the surface of the central support ball generates spiral flow, which enhances the mixing effect of the fluid. The groove depth of 1 mm to 3 mm and the groove width of 2 mm to 5 mm ensure the disturbance effect while avoiding excessive pressure loss. The spiral angle design of 15 degrees to 45 degrees generates a suitable tangential velocity component. The spiral flow effectively reduces the dead zone near the central support ball and improves the fluid utilization efficiency. This surface structure also has a self-cleaning function, reduces the adhesion of contaminants, improves the operating stability of the equipment, and reduces maintenance costs.

[0020] Furthermore, the inner surface of the membrane fixing frame is provided with radially distributed reinforcing ribs, the height of which is 2 mm to 4 mm, the thickness of which is 1 mm to 2 mm, and the number of reinforcing ribs is 8 to 16.

[0021] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the radially distributed reinforcing ribs on the inner surface of the membrane fixation frame improve the structural rigidity and load-bearing capacity of the frame; the 2 mm to 4 mm height of the reinforcing ribs reduces the obstruction to flow while ensuring strength; the 1 mm to 2 mm thickness design optimizes material use; the configuration of 8 to 16 reinforcing ribs ensures the overall strength uniformity of the frame; the radially distributed reinforcing ribs also play a guiding role, improving the flow state of the fluid near the membrane fixation frame, reducing the generation of eddies, and reducing energy consumption; at the same time, the setting of reinforcing ribs increases the service life of the membrane fixation frame.

[0022] Furthermore, the inner surface of the graphite filter membrane is provided with concentric circular grooves, the number of which is 3 to 7, the spacing between adjacent grooves is 0.05 to 0.1 times the radius of the spherical shell, and the groove depth is 0.2 mm to 0.8 mm.

[0023] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the concentric circular groove design on the inner surface of the graphite filter membrane increases the filtration area and improves the filtration efficiency; the configuration of 3 to 7 grooves increases the area while maintaining the integrity of the structure; the design of the spacing between adjacent grooves being 0.05 to 0.1 times the radius of the spherical shell ensures the rationality of the groove distribution; the groove depth of 0.2 mm to 0.8 mm increases the surface area while ensuring the mechanical strength of the filter membrane; the concentric circular grooves also enhance fluid turbulence, reduce concentration polarization, and improve the mass transfer coefficient. This surface structure design effectively improves the separation effect of the reverse osmosis process.

[0024] Compared with existing technologies, the beneficial effects of the filtration membrane structure of the spherical graphite reverse osmosis device provided by this utility model are as follows: This utility model achieves uniform distribution and symmetrical flow of the filter medium through the concentric configuration of the spherical shell and the filter membrane assembly, effectively solving the problem of uneven fluid distribution in traditional flat-plate or tubular reverse osmosis devices. The rational design of the support frame, especially the combination structure of the central support sphere and radial support ribs, provides comprehensive and uniform support for the graphite filter membrane, significantly improving the membrane material's compressive strength and service life. The annular structure of the membrane fixing frame, used in conjunction with the fixing bolts, ensures reliable fixing and uniform stress on the filter membrane, avoiding membrane damage caused by localized stress concentration. The rational configuration of the inlet and outlet water pipes and the design of the guide cone optimize the fluid flow path, reducing the generation of eddies and dead zones, and improving mass transfer efficiency. Innovative designs such as the corrugated structure on the surface of the support ribs, the spiral groove of the central support sphere, and the concentric circular grooves on the inner surface of the filter membrane further enhance fluid turbulence, improve mass transfer conditions, and effectively prevent pollutant deposition and concentration polarization. The entire device has a compact structure, small footprint, strong pressure resistance, high filtration accuracy, low energy consumption, and convenient maintenance. Compared with existing technologies, it has significant improvements in filtration efficiency, membrane life, and operational stability. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the filter membrane structure of a spherical graphite reverse osmosis device. Figure 2 A schematic diagram of the supporting framework; The attached diagram lists the components represented by each number as follows: 10. Spherical outer shell; 20. Filter membrane assembly; 30. Support frame; 40. Inlet pipe; 50. Outlet pipe; 60. Sealing ring. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0028] like Figure 1The diagram shows a schematic representation of the filter membrane structure of a spherical graphite reverse osmosis device provided by this invention. The device includes: a spherical outer shell 10, a filter membrane assembly 20, a support frame 30, an inlet pipe 40, an outlet pipe 50, and a sealing ring 60. The spherical outer shell is made of stainless steel, and its surface has an inlet and an outlet. The inlet is located on the upper hemisphere of the spherical outer shell, and the outlet is located on the lower hemisphere. The filter membrane assembly is disposed inside the spherical outer shell and includes a graphite filter membrane and a membrane fixing frame. The graphite filter membrane is spherical in shape and is attached to the spherical outer shell. The inner surface of the shell is concentrically arranged, and the membrane fixing frame is fixedly connected to the inner wall of the spherical shell through multiple radially distributed connecting rods; the support skeleton is located inside the graphite filter membrane, and the support skeleton is made of polytetrafluoroethylene material. The support skeleton includes a central support ball and multiple radially distributed support ribs. The central support ball is located at the geometric center of the spherical shell. One end of the support rib is fixedly connected to the central support ball, and the other end contacts and supports the inner surface of the graphite filter membrane; the inlet pipe and the outlet pipe are threadedly connected to the inlet and outlet respectively, and the sealing ring is set at the connection between the inlet pipe and the inlet and the outlet pipe and the outlet.

[0029] In the above technical solution, the membrane fixing frame has a ring structure, the outer diameter of the membrane fixing frame matches the inner diameter of the spherical shell, the membrane fixing frame is connected to the inner wall of the spherical shell by at least 6 evenly distributed fixing bolts, the fixing bolts pass through the preset holes on the membrane fixing frame, the bolt heads fit against the inner surface of the membrane fixing frame, and the bolt tails engage with the threaded holes on the inner wall of the spherical shell.

[0030] Furthermore, in the above technical solution, the thickness of the graphite filter membrane is 2 mm to 5 mm, the surface of the graphite filter membrane has a microporous structure with a micropore diameter of 0.1 μm to 0.5 μm, the graphite filter membrane is bonded and fixed to the inner circumferential surface of the membrane fixing frame by epoxy resin adhesive with a bonding width of 3 mm to 8 mm, the graphite filter membrane is bent inward in the bonding area to form a sealing edge, and the sealing edge and the membrane fixing frame form a double sealing structure.

[0031] Furthermore, in the above technical solution, the diameter of the central support ball is 0.15 to 0.25 times the inner diameter of the spherical shell. The surface of the central support ball is provided with multiple through holes, the diameter of which is 3 mm to 6 mm. The axis of the through holes is distributed radially. The number of support ribs is 12 to 18. The support ribs are distributed at equal angles, and the included angle between adjacent support ribs is 20 degrees to 30 degrees. The cross-sectional shape of the support ribs is T-shaped, and the web thickness of the T-shaped cross-section is 1 mm to 3 mm.

[0032] Furthermore, in the above technical solution, the diameter of the spherical shell is 200 mm to 800 mm, the wall thickness of the spherical shell is 8 mm to 15 mm, the spherical shell is composed of an upper hemisphere and a lower hemisphere connected by a flange, the flange is located at the maximum circumference of the spherical shell, the flange faces of the upper hemisphere and the lower hemisphere are sealed by O-rings, and the flange connection is made of high-strength bolts, with the number of bolts being 16 to 24.

[0033] Furthermore, in the above technical solution, both the inlet pipe and the outlet pipe are made of stainless steel. The inner diameter of the inlet pipe is 0.08 to 0.12 times the diameter of the spherical shell, and the inner diameter of the outlet pipe is 0.6 to 0.8 times the inner diameter of the inlet pipe. The length of the inlet pipe extending into the spherical shell is 0.3 to 0.5 times the radius of the spherical shell, and the length of the outlet pipe extending into the spherical shell is 0.2 to 0.4 times the radius of the spherical shell. Both the inlet pipe and the outlet pipe are equipped with guide cones at their ends, and the cone angle of the guide cones is 30 to 60 degrees.

[0034] The following is a specific embodiment 1 of this utility model: In this embodiment, the spherical outer shell is made of 316L stainless steel, with a diameter of 500 mm and a wall thickness of 12 mm, capable of withstanding a maximum working pressure of 3.0 MPa. The spherical outer shell consists of an upper hemisphere and a lower hemisphere, connected by a flange located at the maximum circumference. The flange is 20 mm thick and fixed with 20 M16 high-strength stainless steel bolts. The flange seal uses a fluororubber O-ring. An inlet with a diameter of 50 mm is located on the upper hemisphere, and an outlet with a diameter of 40 mm is located on the lower hemisphere. The graphite filter membrane in the filter membrane assembly is made of high-purity graphite material, with a membrane thickness of 3 mm, an average micropore diameter of 0.3 micrometers, and a porosity of approximately 40%. The membrane fixing frame is made of stainless steel, with an outer diameter of 480 mm, an inner diameter of 470 mm, and a thickness of 10 mm, and is connected to the inner wall of the spherical outer shell with 12 M8 bolts. The graphite filter membrane is bonded to the membrane fixing frame with epoxy resin adhesive, with a bonding width of 5 mm and a bonding strength greater than 2 MPa. The support frame is made of polytetrafluoroethylene (PTFE), with a central support sphere of 100 mm in diameter and 36 through-holes of 5 mm in diameter evenly distributed on its surface. There are 15 support ribs, evenly distributed with an included angle of 24 degrees between adjacent ribs. Each support rib is 190 mm long, has a T-shaped cross-section, a web thickness of 2 mm, and a flange width of 8 mm. The support rib surface is textured with a corrugated structure, with a crest height of 1 mm and a wavelength of 10 mm. The central support sphere surface is textured with helical grooves, 2 mm deep, 3 mm wide, and with a helix angle of 30 degrees, consisting of 6 helical lines. The inner surface of the membrane fixing frame has 12 radial reinforcing ribs, 3 mm high and 1.5 mm thick. The inner surface of the graphite filter membrane has 5 concentric circular grooves, with an adjacent groove spacing of 25 mm and a groove depth of 0.5 mm. Both the inlet and outlet pipes are made of 316L stainless steel. The inlet pipe has an inner diameter of 50 mm, a wall thickness of 3 mm, and extends 75 mm into the spherical outer shell. The outlet pipe has an inner diameter of 40 mm, a wall thickness of 3 mm, and extends 60 mm. Both pipes are equipped with guide cones at the ends, with a cone angle of 45 degrees and a cone length of 30 mm. The sealing rings are made of fluororubber with a hardness of 75 Shore A, maintaining good sealing performance within a temperature range of -20°C to 180°C. After assembly, the entire unit underwent pressure testing, maintaining a pressure of 4.5 MPa for 30 minutes without leakage, meeting design requirements. Filtration performance testing showed that at a working pressure of 2.5 MPa, the unit achieved a rejection rate of over 99.9% for particles larger than 0.1 micrometers in diameter, a removal rate of over 95% for dissolved organic matter, a water production rate of 200 liters per hour, and energy consumption reduced by 15% compared to traditional tubular reverse osmosis units.

[0035] The following is another specific embodiment 2 of this utility model: This embodiment 2 is based on embodiment 1, with optimizations and improvements made to the support frame structure. In this embodiment, the central support sphere adopts a hollow structure design with a wall thickness of 5 mm, and is filled with foam ceramic material to enhance structural strength while reducing weight. The number of through holes on the surface of the central support sphere is increased to 48, and the diameter is reduced to 4 mm. The hole diameter distribution adopts a gradient design, with smaller holes near the poles and larger holes near the equator. This design can better adapt to the flow distribution characteristics inside the spherical structure. The number of support ribs is increased to 18, the included angle between adjacent support ribs is adjusted to 20 degrees, the cross-sectional shape of the support ribs is changed to I-shape, the web thickness is 1.5 mm, and the widths of the upper and lower flanges are 6 mm and 8 mm, respectively. This asymmetrical design makes the contact surface between the support ribs and the filter membrane larger, providing better support. The corrugated structure parameters on the surface of the support ribs are optimized, the peak height is adjusted to 0.8 mm, the wavelength is reduced to 8 mm, and the increased corrugation density improves mass transfer efficiency. The number of spiral grooves on the central support sphere has been increased to eight, the spiral angle has been adjusted to 25 degrees, the groove depth has been reduced to 1.5 mm, but the groove width has been increased to 4 mm, forming a wider and shallower spiral channel, which helps reduce flow resistance. A transition arc structure with a radius of 3 mm has been added at the connection between the support rib and the central support sphere. This design reduces stress concentration and improves the fatigue life of the structure. The number of reinforcing ribs in the membrane fixing frame has been increased to 16, and connecting beams have been added between the reinforcing ribs to form a grid structure, further improving the overall rigidity of the frame.

[0036] Furthermore, in the above technical solution, the surface of the support rib is provided with a corrugated concave-convex structure, the height of the corrugation peak is 0.5 mm to 2 mm, the wavelength is 5 mm to 15 mm, and the corrugation extends along the length direction of the support rib.

[0037] Furthermore, in the above technical solution, the surface of the central support ball is provided with a spiral groove, the groove depth is 1 mm to 3 mm, the groove width is 2 mm to 5 mm, and the spiral angle of the spiral groove is 15 degrees to 45 degrees.

[0038] Furthermore, in the above technical solution, the inner surface of the membrane fixing frame is provided with radially distributed reinforcing ribs, the height of which is 2 mm to 4 mm, the thickness of which is 1 mm to 2 mm, and the number of reinforcing ribs is 8 to 16.

[0039] Furthermore, in the above technical solution, the inner surface of the graphite filter membrane is provided with concentric circular grooves, the number of which is 3 to 7, the spacing between adjacent grooves is 0.05 to 0.1 times the radius of the spherical shell, and the groove depth is 0.2 mm to 0.8 mm.

[0040] Specifically, the principle of this invention is as follows: Based on fluid mechanics and membrane separation theory, this invention addresses existing problems by optimizing the structural design of the spherical reverse osmosis device. First, a concentric configuration of the spherical shell and graphite filter membrane is adopted. The geometric characteristics of the spherical structure achieve symmetrical fluid distribution, eliminating the uneven flow distribution common in traditional flat or tubular structures. The spherical structure has the smallest surface area to volume ratio, achieving the smallest equipment volume for the same filtration area. Simultaneously, the isotropic pressure-bearing characteristics of the spherical structure allow it to withstand higher operating pressures. The support frame design employs a combination of a central support sphere and radial support ribs. The central support sphere is located at the geometric center of the spherical shell, and the radially distributed support ribs uniformly transfer the supporting force to the filter membrane surface. This structural design, based on mechanical analysis, ensures the uniformity of stress on the filter membrane. The corrugated structure on the support rib surface and the spiral groove design of the central support sphere are based on boundary layer theory, improving mass transfer conditions and reducing concentration polarization by enhancing fluid disturbance. The concentric groove design on the inner surface of the filter membrane not only increases the filtration area but also enhances mass transfer by altering the fluid flow path. The annular structure design of the membrane fixing frame, based on stress analysis, ensures the stability and sealing of the filter membrane under high pressure differential. The configuration of the inlet and outlet water pipes and the design of the guide cone are based on fluid mechanics optimization, reducing flow resistance and energy consumption. The design of the entire device fully considers theories from multiple disciplines such as fluid mechanics, mass and heat transfer, and materials mechanics, resulting in a structurally sound and high-performance spherical graphite reverse osmosis unit.

[0041] In operation, first install the spherical graphite reverse osmosis unit into the treatment system. Connect the inlet pipe to the raw water supply system via flanges, and connect the outlet pipe to the purified water collection system, ensuring good sealing at all connections. Before starting the system, check the integrity of the spherical shell, confirm that the filter membrane assembly is installed correctly, the support frame is accurately positioned, and all sealing rings are in good condition. When starting the system, gradually increase the inlet pressure, setting the initial pressure to approximately 30% of the working pressure. Observe the system's operating status, and after confirming there are no leaks, gradually increase it to the working pressure. During normal operation, raw water enters the upper part of the spherical shell through the inlet pipe and is evenly dispersed into the spherical space under the guidance of the guide cone at the end of the inlet pipe. Driven by pressure, the raw water passes through the graphite filter membrane for separation and purification. The purified water is collected from the inside of the filter membrane and discharged through the outlet pipe. During operation, it is necessary to regularly monitor the inlet and outlet water pressure, flow rate, and water quality parameters. When the pressure difference exceeds the set value, cleaning and maintenance are required. During cleaning, first reduce the system pressure, close the inlet valve, and backwash the system by introducing cleaning solution in reverse through the outlet pipe. The cleaning solution can be purified water or a specialized cleaning agent. The cleaning time depends on the degree of membrane fouling. After cleaning, rinse thoroughly with purified water. Once the effluent quality is confirmed to be acceptable, resume normal operation. For long-term shutdown, the system needs to be protected by draining accumulated water and refilling with protective solution to ensure that the filter membrane is not damaged due to drying.

Claims

1. A filter membrane structure for a spherical graphite reverse osmosis device, characterized in that, include: The system comprises a spherical outer shell, a filter membrane assembly, a support frame, an inlet pipe, an outlet pipe, and a sealing ring. The spherical outer shell is made of stainless steel and has an inlet and an outlet on its surface. The inlet is located on the upper hemisphere of the spherical outer shell, and the outlet is located on the lower hemisphere. The filter membrane assembly is disposed inside the spherical outer shell and includes a graphite filter membrane and a membrane fixing frame. The graphite filter membrane is spherical and concentrically arranged with the inner surface of the spherical outer shell. The membrane fixing frame is fixedly connected to the inner wall of the spherical outer shell by multiple radially distributed connecting rods. The support frame is located inside the graphite filter membrane and is made of polytetrafluoroethylene (PTFE). The support frame includes a central support sphere and multiple radially distributed support ribs. The central support sphere is located at the geometric center of the spherical outer shell. One end of each support rib is fixedly connected to the central support sphere, and the other end contacts and supports the inner surface of the graphite filter membrane. The inlet pipe and outlet pipe are threadedly connected to the inlet and outlet, respectively. The sealing ring is disposed at the connection between the inlet pipe and the inlet, and between the outlet pipe and the outlet.

2. The filter membrane structure of the spherical graphite reverse osmosis device according to claim 1, characterized in that, The membrane fixing frame has a ring structure. The outer diameter of the membrane fixing frame matches the inner diameter of the spherical shell. The membrane fixing frame is connected to the inner wall of the spherical shell by at least 6 evenly distributed fixing bolts. The fixing bolts pass through the preset holes on the membrane fixing frame. The bolt heads fit against the inner surface of the membrane fixing frame, and the bolt tails engage with the threaded holes on the inner wall of the spherical shell.

3. The filter membrane structure of the spherical graphite reverse osmosis device according to claim 2, characterized in that, The graphite filter membrane has a thickness of 2 mm to 5 mm and a microporous structure on its surface with a micropore diameter of 0.1 μm to 0.5 μm. The graphite filter membrane is bonded and fixed to the inner circumferential surface of the membrane fixing frame by epoxy resin adhesive with a bonding width of 3 mm to 8 mm. The graphite filter membrane is bent inward in the bonding area to form a sealing edge, and the sealing edge and the membrane fixing frame form a double sealing structure.

4. The filter membrane structure of a spherical graphite reverse osmosis device according to claim 3, characterized in that, The diameter of the central support sphere is 0.15 to 0.25 times the inner diameter of the spherical shell. The surface of the central support sphere has multiple through holes with a diameter of 3 mm to 6 mm. The through holes are radially distributed along their axes. The number of support ribs is 12 to 18. The support ribs are distributed at equal angles, with an included angle of 20 degrees to 30 degrees between adjacent support ribs. The cross-sectional shape of the support ribs is T-shaped, and the web thickness of the T-shaped cross-section is 1 mm to 3 mm.

5. The filter membrane structure of a spherical graphite reverse osmosis device according to claim 4, characterized in that, The spherical shell has a diameter of 200 mm to 800 mm and a wall thickness of 8 mm to 15 mm. The spherical shell is composed of an upper hemisphere and a lower hemisphere connected by a flange. The flange is located at the maximum circumference of the spherical shell. The flange faces of the upper and lower hemispheres are sealed by O-rings. The flange connection uses high-strength bolts, with 16 to 24 bolts.

6. The filter membrane structure of a spherical graphite reverse osmosis device according to claim 5, characterized in that, Both the inlet and outlet pipes are made of stainless steel. The inner diameter of the inlet pipe is 0.08 to 0.12 times the diameter of the spherical shell, and the inner diameter of the outlet pipe is 0.6 to 0.8 times the inner diameter of the inlet pipe. The length of the inlet pipe extending into the spherical shell is 0.3 to 0.5 times the radius of the spherical shell, and the length of the outlet pipe extending into the spherical shell is 0.2 to 0.4 times the radius of the spherical shell. Both the inlet and outlet pipes are equipped with guide cones at their ends, with a cone angle of 30 to 60 degrees.

7. The filter membrane structure of a spherical graphite reverse osmosis device according to claim 6, characterized in that, The surface of the support rib is provided with a corrugated concave-convex structure, the height of the corrugations is 0.5 mm to 2 mm, the wavelength is 5 mm to 15 mm, and the corrugations extend along the length of the support rib.

8. The filter membrane structure of a spherical graphite reverse osmosis device according to claim 7, characterized in that, The surface of the central support ball is provided with a spiral groove, the groove depth is 1 mm to 3 mm, the groove width is 2 mm to 5 mm, and the spiral angle of the spiral groove is 15 degrees to 45 degrees.

9. The filter membrane structure of a spherical graphite reverse osmosis device according to claim 8, characterized in that, The inner surface of the membrane fixing frame is provided with radially distributed reinforcing ribs, the height of which is 2 mm to 4 mm, the thickness of which is 1 mm to 2 mm, and the number of reinforcing ribs is 8 to 16.

10. The filter membrane structure of a spherical graphite reverse osmosis device according to claim 9, characterized in that, The inner surface of the graphite filter membrane is provided with concentric circular grooves, the number of which is 3 to 7. The spacing between adjacent grooves is 0.05 to 0.1 times the radius of the spherical shell, and the groove depth is 0.2 mm to 0.8 mm.

Images