Ultrafiltration membrane system for concentrating skimmed milk

Abstract

The invention relates to the field of dairy product processing, in particular to an ultrafiltration membrane system for skimmed milk concentration, which comprises an ultrafiltration membrane unit, a pipeline unit and a pressurizing unit, the ultrafiltration membrane unit comprises a pipe body and membrane filaments, the pipe body is provided with a first inlet, a second inlet and a discharge port, and the membrane filaments are arranged in the pipe body. A plurality of membrane filaments coaxial with the tube body are arranged in the tube body, a barrel body for fixedly connecting all the membrane filaments is movably arranged in the tube body, and driving assemblies for driving the barrel body to move are arranged in the positions, located at the first inlet and the second inlet, in the tube body; the upper end and the lower end of the barrel are provided with an upper end cover and a lower end cover which are in transmission connection with the corresponding driving assemblies respectively. The driving assembly drives the barrel to move, turbulent flow around the membrane filaments is promoted, the concentration polarization phenomenon is reduced, in addition, a backwashing program is started regularly, the driving assembly drives the barrel to move, blockages on the inner sides of the membrane filaments are effectively removed, and the flux of the membrane is recovered.

Description

Technical Field

[0001] The invention relates to the field of dairy product processing, in particular to an ultrafiltration membrane system for skimmed milk concentration. Background Art

[0002] Skim milk is a product obtained by removing the fat component from milk. It has low calories and high nutritional value. Ultrafiltration is a pressure-driven membrane separation technology that uses the selective permeability of a semipermeable membrane to separate different components in a liquid. The pore size of an ultrafiltration membrane is usually between 0.01 and 0.1 microns, which can effectively retain macromolecules such as protein, fat and lactose, while allowing water and small molecular solutes to pass through. The traditional vacuum evaporation technology has a long concentration process for refining dairy products and harsh processing conditions, which is not suitable for the current fast and efficient production needs of the dairy industry.

[0003] The currently disclosed Chinese patent CN221813121U discloses an ultrafiltration membrane filtering device for fresh milk concentration, comprising a first fresh milk collection box, a first ultrafiltration membrane filter cartridge, a first clean water discharge pipe, a first pressure pump, a second fresh milk collection box, a second ultrafiltration membrane filter cartridge, a second clean water discharge pipe, a second pressure pump, a third fresh milk collection box, a third ultrafiltration membrane filter cartridge, a third clean water discharge pipe, a third pressure pump, and a collection box; the output pipe at the bottom of the first fresh milk collection box is connected to the input pipe of the first ultrafiltration membrane filter cartridge; the first fresh milk chamber, the first ultrafiltration membrane and the first clean water chamber are sequentially arranged in the inner cavity of the first ultrafiltration membrane filter cartridge from the center to the outside; the first clean water discharge pipe is arranged outside the first ultrafiltration membrane filter cartridge, and the first clean water discharge pipe is connected to the first clean water chamber through a pipeline to discharge the liquid in the first clean water chamber; the first air supply port is arranged on the input pipe of the first ultrafiltration membrane filter cartridge, and the first pressure pump is connected to the first air supply port through a pipeline.

[0004] The above-mentioned ultrafiltration membrane filtration device pressurizes the first fresh milk chamber, the second fresh milk chamber, and the third fresh milk chamber respectively through the first booster pump, the second booster pump, and the third booster pump, and concentrates the fresh milk by adjusting the boost pressure and the filtering effect of the ultrafiltration membrane, and the efficiency of concentrating the fresh milk is higher. However, the surface of the ultrafiltration membrane is susceptible to the deposition of substances such as protein, fat, and lactose, which causes the membrane flux to drop rapidly, increases the cleaning frequency and maintenance costs. The solute concentration gradient near the membrane surface will lead to a decrease in filtration efficiency, increase filtration resistance, and thus affect the overall production efficiency. In addition, during the concentration process, dissolved gases may form bubbles and adhere to the surface of the membrane filaments, reducing the effective filtration area, affecting the mass transfer efficiency and the working environment of the membrane filaments. Therefore, there is a need for an ultrafiltration membrane system for skimmed milk concentration that can improve filtration efficiency. Summary of the invention

[0005] In view of the problems existing in the prior art, an ultrafiltration membrane system for skimmed milk concentration is provided. The present invention drives the cylinder to move through a driving component to promote turbulence around the membrane filaments, break the boundary layer on the surface of the membrane filaments, reduce concentration polarization, and further improve the flux and filtration efficiency of the membrane. In addition, in order to remove the sediment inside the membrane filaments, a backwashing program is started regularly. At this time, the driving component drives the cylinder to move, which effectively removes the blockage inside the membrane filaments and restores the flux of the membrane.

[0006] To solve the problems in the prior art, the present invention provides an ultrafiltration membrane system for skimmed milk concentration, comprising an ultrafiltration membrane unit, a pipeline unit and a pressurizing unit, wherein the ultrafiltration membrane unit comprises a vertically arranged tube body and membrane filaments arranged in the tube body, the tube body having a first inlet and a second inlet connected to the pipeline unit for introducing skimmed milk, the first inlet and the second inlet are respectively arranged at positions of the tube body close to the upper end and the lower end thereof, the tube body also having a discharge port connected to the pipeline unit for discharging skimmed milk, the discharge port being arranged at the upper end of the tube body, a plurality of coaxial membrane filaments are arranged in the tube body, the membrane filaments are tubular structures with micropores, a cylinder body to which all the membrane filaments are fixedly connected is movably arranged in the tube body, a filtering area is formed between the cylinder body and all the membrane filaments, a driving assembly for driving the cylinder body to move is arranged in the tube body and at the positions of the first inlet and the second inlet, the upper end and the lower end of the cylinder body respectively have an upper end cover and a lower end cover which are transmission-connected to the corresponding driving assembly, and the discharge port has a conduit extending through the upper end cover to the filtering area.

[0007] Preferably, an upper sealing ring tightly fitting with the upper end cover and a lower sealing ring tightly fitting with the lower end cover are fixedly provided in the tube body, and a gap is reserved between the upper sealing ring and the lower sealing ring for the cylinder body to move therein. When skim milk is introduced into the first inlet and the second inlet at the same time, the skim milk enters the membrane filaments and penetrates into the filtering area.

[0008] Preferably, a guide shaft is fixedly provided at the lower end of the tube body, which passes through the lower end cover and extends into the filtering area. The guide shaft is coaxial with the cylinder. The upper end cover and the lower end cover respectively have guide sleeves slidably mounted on the conduit and the guide shaft. The extended end of the guide shaft is close to the conduit. The driving assembly includes a rotating driver for driving the cylinder to rotate and a vibration driver for driving the cylinder to vibrate up and down during the rotation of the cylinder.

[0009] Preferably, the rotary driver has an impeller that is coaxial with and rotatably connected to the tube body, and a clamping strip arranged on the impeller and extending toward the cylinder body. Ring sleeves are fixedly sleeved on the guide sleeves of the upper end cover and the lower end cover, and each of the ring sleeves is provided with a clamping groove along its axial direction for the corresponding clamping strip to slide and engage. An impeller is provided at the position of the first inlet and the second inlet. When skimmed milk is introduced into the first inlet and the second inlet at the same time and impacts the impeller, all the impellers are in a rotating state, so that the upper end cover and the lower end cover are in a synchronous rotating state with the cooperation of the clamping strip and the clamping groove, thereby causing the bubbles attached to the membrane filaments to detach.

[0010] Preferably, the guide shaft can rotate in the tube body, and the tube body is provided with a motor for driving the guide shaft to rotate opposite to the cylinder body. The part of the guide shaft extending into the filtration area is spirally wound with a dividing strip. When the guide shaft and the cylinder body rotate synchronously and oppositely, the separated bubbles are in a ruptured state due to the stirring of the dividing strip.

[0011] Preferably, the guide shaft is provided with an air passage for hot air to pass from its lower end along its axial direction. When hot air passes into the air passage of the guide shaft, the guide shaft is in a heated state, so that the viscosity of the skim milk is reduced, thereby reducing the filtration resistance of the membrane wire.

[0012] Preferably, the vibration driver has a movable part fixedly arranged on the guide sleeve of the lower end cover and a fixed part fixedly arranged on the tube body, the fixed part is located below the movable part, the fixed part and the movable part are both annular structures, the upper surface of the fixed part has a protrusion, and the lower surface of the movable part has a plurality of protrusions evenly distributed around its circumference. When the cylinder rotates, all the protrusions continuously pass through the protrusions, so that the cylinder is in a state of up and down vibration, thereby causing the dirt inside the membrane filament to fall off when the membrane filament is backwashed.

[0013] Preferably, the protrusions are specifically balls that are in rolling contact with the lower surface of the movable part, the upper surface of the fixed part is evenly distributed with a plurality of the balls along its circumferential direction, and each protrusion has an inclined surface at one end passing through the ball.

[0014] Preferably, a spring is provided between each ring sleeve and the corresponding impeller to act as a buffer during the vibration of the cylinder.

[0015] Preferably, a support portion is provided between the tube body and the cylinder body to keep the two coaxial, the support portion is a spherical structure, and a groove for the support portion to be embedded is provided on the tube body and the cylinder body.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention drives the cylinder to move through the driving assembly, promotes turbulence around the membrane filaments, breaks the boundary layer on the surface of the membrane filaments, reduces the concentration polarization phenomenon, and further improves the flux and filtration efficiency of the membrane. In addition, in order to remove the sediment inside the membrane filaments, the backwashing program is started regularly. At this time, the driving assembly drives the cylinder to move, and the cleaning liquid is used to backwash the membrane filaments through the discharge port. The blockages on the inside of the membrane filaments are effectively removed, the flux of the membrane is restored, and the long-term stable operation of the membrane filaments is ensured. It not only improves the concentration efficiency of skimmed milk, but also extends the service life of the membrane filaments, ensuring efficient and stable filtration performance.

[0017] 2. The present invention causes the impeller to start rotating by rotating the impeller, that is, skimmed milk impacts the impeller with a certain pressure. Since the impellers at the first inlet and the second inlet are impacted at the same time, all the impellers are in a rotating state. In combination with the cooperation of the card strip and the card slot, the upper end cover and the lower end cover rotate synchronously, generating a significant centrifugal force, thereby causing the bubbles attached to the surface of the membrane to detach quickly. The blockage of the membrane pore diameter is reduced, and the flux and filtration efficiency of the membrane are further improved.

[0018] 3. The present invention uses the synchronous and opposite rotation of the guide shaft and the cylinder, as well as the stirring action of the dividing strip, to quickly rupture the separated bubbles, thereby reducing the blockage of the membrane pores. The rupture and further dispersion of the bubbles keep the membrane surface clean, thereby significantly improving the flux and filtration efficiency of the membrane.

[0019] 4. The present invention generates up and down vibrations during the rotation of the cylinder through the vibration driver, that is, the cooperation of the convex blocks and the convex points ensures that the cylinder vibrates continuously during the rotation process. The impact force of the water flow during backwashing is enhanced, making it easier to remove the sediment inside the membrane filaments, and improving the uniformity and thoroughness of cleaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional structural schematic diagram of an ultrafiltration membrane system for skimmed milk concentration.

[0021] Figure 2 The present invention is a partial three-dimensional structural cross-sectional view of an ultrafiltration membrane system for skimmed milk concentration.

[0022] Figure 3 The present invention is a partial plan cross-sectional view of an ultrafiltration membrane system for skimmed milk concentration.

[0023] Figure 4 yes Figure 3 A cross-sectional view of the three-dimensional structure at AA.

[0024] Figure 5 yes Figure 3 A cross-sectional view of the three-dimensional structure at BB.

[0025] Figure 6It is a three-dimensional structural diagram of an ultrafiltration membrane system for removing a tube body for skimmed milk concentration.

[0026] Figure 7 The diagram is a partial three-dimensional structural diagram of a cylinder and membrane fibers of an ultrafiltration membrane system for skimmed milk concentration.

[0027] Figure 8 The invention is a three-dimensional structural diagram of an upper end cover and a rotary drive of an ultrafiltration membrane system for skimmed milk concentration.

[0028] Fig. 9 The present invention is a three-dimensional structural schematic diagram of a rotary driver of an ultrafiltration membrane system for skimmed milk concentration.

[0029] Fig.10 The present invention is a three-dimensional structural diagram of a lower end cover and a rotary driver of an ultrafiltration membrane system for skimmed milk concentration.

[0030] The numbers in the figure are: 1-tube body; 11-first inlet; 12-second inlet; 13-discharge outlet; 131-conduit; 132-guide shaft; 1321-dividing strip; 1322-airway; 14-support part; 2-membrane wire; 21-filtration area; 3-cylinder body; 31-upper end cover; 311-upper sealing ring; 312-guide sleeve; 313-ring sleeve; 32-lower end cover; 321-lower sealing ring; 4-drive assembly; 41-rotational drive; 411-impeller; 412-strap; 42-vibration drive; 421-fixed part; 4211-bump; 422-movable part; 4221-bump; 423-spring. DETAILED DESCRIPTION

[0031] In order to further understand the features, technical means, specific objectives and functions of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0032] See also Figure 1-Figure 7As shown, an ultrafiltration membrane system for skimmed milk concentration comprises an ultrafiltration membrane unit, a pipeline unit and a pressurizing unit, wherein the ultrafiltration membrane unit comprises a vertically arranged tube body 1 and membrane threads 2 arranged in the tube body 1, the tube body 1 has a first inlet 11 and a second inlet 12 connected to the pipeline unit for introducing skimmed milk, the first inlet 11 and the second inlet 12 are respectively arranged at positions close to the upper end and the lower end of the tube body 1, the tube body 1 also has a discharge port 13 connected to the pipeline unit for discharging skimmed milk, the discharge port 13 is arranged at the upper end of the tube body 1, a plurality of coaxial membrane threads 2 are arranged in the tube body 1, and the membrane threads 2 It is a tubular structure with micropores. A cylinder 3 for fixedly connecting all membrane threads 2 is movably provided in the tube body 1. A filtration area 21 is formed between the cylinder 3 and all membrane threads 2. A driving component 4 for driving the cylinder 3 to move is provided in the tube body 1 and at the positions of the first inlet 11 and the second inlet 12. The upper and lower ends of the cylinder 3 respectively have an upper end cover 31 and a lower end cover 32 that are transmission-connected to the corresponding driving component 4. The discharge port 13 has a conduit 131 that extends through the upper end cover 31 to the filtration area 21. When the skim milk is concentrated, the skim milk passes through the membrane threads 2 and is in a flow state from the inside to the outside into the filtration area 21.

[0033] When skimmed milk is transported to the first inlet 11 or the second inlet 12 of the ultrafiltration membrane unit through the pipeline unit, the skimmed milk is subjected to the pressure provided by the pressurizing unit and flows to the membrane filaments 2 through the internal channel of the tube body 1. At this time, the membrane filaments 2 are in a vertical arrangement state, and each membrane filament 2 has a tiny pore size, which can selectively pass through the components in the liquid under the action of a high pressure difference. Since the inner wall of the membrane filament 2 is smooth and has high flux characteristics, water and small molecular solutes can quickly pass through the wall of the membrane filament 2 and enter the filtration area 21 outside the membrane filament 2, while large molecular substances are retained on the inside of the membrane filament 2. In this process, the skimmed milk is in a state of flowing from the inside to the outside into the filtration area 21.

[0034] As skimmed milk continues to pass through the membrane filaments 2, macromolecular substances are trapped inside the membrane filaments 2. The filtered skimmed milk is finally discharged from the discharge port 13. During this period, the drive assembly 4 will drive the cylinder 3 to move as needed, which can form a certain turbulence around the membrane filaments 2, helping to break the boundary layer on the surface of the membrane filaments 2 and reduce concentration polarization, thereby improving the flux and filtration efficiency of the membrane. In order to improve the concentration efficiency, the backwashing procedure can be started regularly during the concentration process, and the cleaning liquid can be used to reversely flush the membrane filaments 2 through the discharge port 13. The drive assembly 4 can also drive the cylinder 3 to move, and cooperate with the cleaning liquid to reversely flush the membrane filaments 2 through the discharge port 13, effectively removing the sediment on the inside of the membrane filaments 2 and restoring the flux of the membrane.

[0035] See also Figure 2 and Figure 3As shown, an upper sealing ring 311 tightly fitted with the upper end cover 31 and a lower sealing ring 321 tightly fitted with the lower end cover 32 are fixedly provided in the tube body 1, and a gap is reserved between the upper sealing ring 311 and the lower sealing ring 321 for the cylinder body 3 to move therein. When skim milk is introduced into the first inlet 11 and the second inlet 12 at the same time, the skim milk is in a pressurized state in the tube body 1, so that the skim milk enters the membrane filament 2 and penetrates into the filtration area 21.

[0036] When skimmed milk is introduced into the first inlet 11 and the second inlet 12 at the same time, the skimmed milk is subjected to the pressure provided by the pressurizing unit in the tube body 1. The design of the double inlet allows the skimmed milk to enter the tube body 1 from two directions, forming a more uniform pressure distribution. Due to the pressurization, the skimmed milk is forced to enter the vertically arranged membrane filaments 2. Each membrane filament 2 has a tiny pore size. Under the action of the high pressure difference, water and small molecular solutes quickly pass through the membrane filament 2 and enter the outer filtration area 21, while macromolecular substances are trapped inside the membrane filament 2. In the process of the drive assembly 4 driving the cylinder 3 to move, the upper sealing ring 311 and the lower sealing ring 321 ensure the sealing between the tube body 1 and the cylinder 3. Even under high pressure, the skimmed milk will only enter the membrane filament 2 and will not remain in the tube body 1, ensuring the accuracy of the skimmed milk concentration process.

[0037] See also Figure 2 and Figure 3 As shown, a guide shaft 132 is fixedly provided at the lower end of the tube body 1, passing through the lower end cover 32 and extending to the filtering area 21. The guide shaft 132 is coaxial with the cylinder 3. The upper end cover 31 and the lower end cover 32 respectively have guide sleeves 312 slidably mounted on the guide tube 131 and the guide shaft 132. The extending end of the guide shaft 132 is close to the guide tube 131. The driving assembly 4 includes a rotating driver 41 for driving the cylinder 3 to rotate and a vibration driver 42 for driving the cylinder 3 to vibrate up and down during the rotation of the cylinder 3.

[0038] When skim milk is introduced into the first inlet 11 and the second inlet 12 at the same time, the pressure provided by the pressurizing unit causes the skim milk to enter the tube body 1 and penetrate into the membrane filament 2 under the action of the high pressure difference. At this time, the skim milk is in a pressurized state, water and small molecular solutes penetrate the membrane filament 2 into the outer filtration area 21, and macromolecular substances are trapped inside the membrane filament 2. After the rotary driver 41 is started, the cylinder 3 is driven to rotate, and the rotary motion causes the bubbles attached to the surface of the membrane filament 2 to detach from the surface of the membrane filament 2, reducing the blockage of the pore size of the membrane filament 2 by the bubbles, thereby increasing the flux of the membrane and promoting more efficient filtration. During the rotation of the cylinder 3, the vibration driver 42 is started synchronously to drive the cylinder 3 to vibrate up and down. The vibration motion breaks the boundary layer on the surface of the membrane filament 2, promotes the formation of turbulence around the membrane filament 2, reduces the concentration polarization phenomenon, and further improves the flux and filtration efficiency of the membrane. During the vibration of the cylinder 3, the guide sleeve 312 slides on the conduit 131 and the guide shaft 132 to ensure that the cylinder 3 always maintains vertical alignment and smooth movement during rotation and vibration. In order to remove the sediment inside the membrane filaments 2, the backwashing procedure is started regularly. At this time, the drive assembly 4 continues to drive the cylinder 3 to rotate and vibrate, and cooperates with the cleaning liquid to backwash the membrane filaments 2 through the discharge port 13, effectively removing the dirt inside the membrane filaments 2 and restoring the flux of the membrane.

[0039] See also Figure 2 , Figure 3 and Figure 5-Figure 10 As shown, the rotary driver 41 has an impeller 411 that is coaxial with and rotatably connected to the tube body 1, and a clamping strip 412 that is arranged on the impeller 411 and extends toward the cylinder 3. The guide sleeves 312 of the upper end cover 31 and the lower end cover 32 are fixedly sleeved with a ring sleeve 313, and each of the ring sleeves 313 is provided with a clamping groove along its axial direction for the corresponding clamping strip 412 to slide and clamp. An impeller 411 is provided at the position of the first inlet 11 and the second inlet 12. When skimmed milk is introduced into the first inlet 11 and the second inlet 12 at the same time and impacts the impeller 411, all the impellers 411 are in a rotating state, so that the upper end cover 31 and the lower end cover 32 are in a synchronous rotating state under the cooperation of the clamping strip 412 and the clamping groove, thereby causing the bubbles attached to the membrane filament 2 to detach.

[0040] When skim milk is introduced into the first inlet 11 and the second inlet 12 at the same time, the skim milk impacts the impeller 411 with a certain pressure, causing the impeller 411 to start rotating. Since the impellers 411 at the two inlets are impacted at the same time, all the impellers 411 are in a rotating state. When the impeller 411 rotates, the clamping strip 412 thereon is tightly matched with the ring sleeve 313 through the clamping groove, driving the guide sleeve 312 of the upper end cover 31 and the lower end cover 32 to rotate synchronously. In the process of the impeller 411 driving the upper end cover 31 and the lower end cover 32 to rotate synchronously, the cylinder 3 also rotates with it. The centrifugal force generated by the rotational motion causes the bubbles attached to the surface of the membrane filament 2 to gradually move to the edge of the cylinder 3, and finally separate from the surface of the membrane filament 2. The action of the centrifugal force effectively reduces the blockage of the pore size of the membrane filament 2 by the bubbles, thereby improving the flux and filtration effect of the membrane.

[0041] See also Figure 2-Figure 4 As shown, the guide shaft 132 can rotate in the tube body 1, and a motor is provided on the tube body 1 to drive the guide shaft 132 to rotate opposite to the cylinder 3. The part of the guide shaft 132 extending into the filtration area 21 is spirally wound with a dividing strip 1321. When the guide shaft 132 and the cylinder 3 rotate synchronously and oppositely, the separated bubbles are in a ruptured state under the stirring of the dividing strip 1321.

[0042] When the motor is started, the guide shaft 132 starts to rotate synchronously with the cylinder 3, but in opposite directions. The opposite rotation not only causes the bubbles to be separated from the surface of the membrane filament 2 by the centrifugal force, but also to be continuously stirred by the dividing strip 1321. During the process of synchronous and opposite rotation of the guide shaft 132 and the cylinder 3, the separated bubbles enter the spiral channel formed by the dividing strip 1321. The stirring action of the dividing strip 1321 causes the bubbles to continuously collide and split, and finally to be in a ruptured state. This process further reduces the blockage of the pore size of the membrane filament 2 by the bubbles, and improves the flux and filtration effect of the membrane.

[0043] See also Figure 2 As shown, the guide shaft 132 is provided with an air passage 1322 for hot air to pass through from its lower end along its axial direction. When hot air passes into the air passage 1322 of the guide shaft 132, the guide shaft 132 is in a heated state, so that the viscosity of the skim milk is reduced, thereby reducing the filtration resistance of the membrane filament 2.

[0044] When hot air is introduced into the air passage 1322 of the guide shaft 132 through an external air pump, the hot air flows inside the guide shaft 132 and transfers heat. Since the guide shaft 132 is in direct contact with the hot air, its temperature rises rapidly and reaches a heated state. After the guide shaft 132 is heated, the skim milk around it is also affected by heat conduction, and the temperature rises accordingly. As the temperature rises, the viscosity of the skim milk decreases significantly. The lower viscosity makes the skim milk easier to flow, reducing its resistance when passing through the membrane filament 2. After the viscosity is reduced, the skim milk encounters less resistance when passing through the membrane filament 2, thereby improving the filtration efficiency. The lower filtration resistance not only speeds up the filtration speed, but also reduces the pressure on the membrane filament 2, extending the service life of the membrane filament 2. See also Figure 2 , Figure 3 , Figure 6 and Fig.10 As shown, the vibration driver 42 has a movable part 422 fixedly arranged on the guide sleeve 312 of the lower end cover 32 and a fixed part 421 fixedly arranged on the tube body 1, the fixed part 421 is located below the movable part 422, and the fixed part 421 and the movable part 422 are both annular structures, the upper surface of the fixed part 421 has a protrusion 4211, and the lower surface of the movable part 422 has a plurality of protrusions 4221 evenly distributed around its circumferential direction. When the cylinder 3 rotates, all the protrusions 4221 continuously pass through the protrusions 4211, so that the cylinder 3 is in a state of up and down vibration, thereby causing the dirt inside the membrane filament 2 to fall off when the membrane filament 2 is backwashed.

[0045] When the cylinder 3 rotates, the movable part 422 rotates with the cylinder 3. Due to the relative movement between the movable part 422 and the fixed part 421, the bumps 4221 on the movable part 422 continuously pass by the protrusions 4211 on the fixed part 421. Every time a bump 4221 passes by the protrusion 4211, an instantaneous impact force is generated, causing the movable part 422 and the entire cylinder 3 to vibrate up and down. During the backwashing of the membrane filaments 2, this up and down vibration further enhances the impact force of the water flow, making it easier for the sediments attached to the inside of the membrane filaments 2 to fall off. The vibration destroys the adhesion between the sediments and the surface of the membrane filaments 2, thereby improving the cleaning effect.

[0046] See also Figure 2 , Figure 3 , Figure 6 and Fig.10 As shown, the protrusion 4211 is specifically a ball rolling in contact with the lower surface of the movable portion 422, and a plurality of the balls are evenly distributed on the upper surface of the fixed portion 421 along its circumferential direction. Each protrusion 4221 has an inclined surface at one end passing through the ball.

[0047] When the cylinder 3 rotates, the protrusion 4221 on the movable part 422 continuously passes by the ball on the fixed part 421. Due to the inclined surface design at one end of the protrusion 4221, when passing by the ball, the inclined surface will gradually press against the ball, generating an impact force, causing the movable part 422 and the entire cylinder 3 to move upward. After the protrusion 4221 passes by the ball, it automatically resets downward under the action of gravity of the cylinder 3. The protrusion 4221 periodically passes by the ball, thereby realizing the vibration of the cylinder 3. The rolling contact of the ball reduces the friction, allowing the protrusion 4221 to pass by the ball more smoothly.

[0048] See also Figure 2 , Figure 3 and Figure 8-Figure 10 As shown, a spring 423 is provided between each ring sleeve 313 and the corresponding impeller 411 to act as a buffer during the vibration of the cylinder 3 .

[0049] When the cylinder 3 vibrates up and down during rotation, the ring sleeve 313 will vibrate accordingly. Due to the presence of the spring 423, when the ring sleeve 313 is subjected to an upward impact force, the spring 423 at the upper end cover 31 is compressed and absorbs part of the energy. Similarly, when the ring sleeve 313 moves downward, the spring 423 at the lower end cover 32 is compressed, further playing a buffering role, and effectively protecting the cylinder 3 from the influence of severe vibration.

[0050] See also Figure 2-Figure 4 and Figure 6 As shown, a support portion 14 is provided between the tube body 1 and the cylinder body 3 to keep the two coaxial. The support portion 14 is a spherical structure. Both the tube body 1 and the cylinder body 3 are provided with a groove for the support portion 14 to be embedded.

[0051] When the tube body 1 and the cylinder body 3 move relative to each other, the support part 14 of the spherical structure can rotate freely in the groove, ensuring that the tube body 1 and the cylinder body 3 are always in a coaxial state, compensating for deviations caused by vibration and rotation factors, thereby maintaining the coaxiality of the two and reducing the possibility of wear and failure.

[0052] The present invention drives the cylinder 3 to move through the driving component 4, promotes turbulence around the membrane filaments 2, breaks the boundary layer on the surface of the membrane filaments 2, reduces the concentration polarization phenomenon, and further improves the flux and filtration efficiency of the membrane; in addition, in order to remove the sediment inside the membrane filaments 2, the backwashing program is started regularly; at this time, the driving component 4 drives the cylinder 3 to move, and cooperates with the cleaning liquid to backwash the membrane filaments 2 through the discharge port 13; the blockage inside the membrane filaments 2 is effectively removed, the flux of the membrane is restored, and the membrane filaments 2 are ensured to operate stably for a long time, which not only improves the concentration efficiency of skimmed milk, but also extends the service life of the membrane filaments 2, ensuring efficient and stable filtration performance.

[0053] The above embodiments only express one or several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. An ultrafiltration membrane system for skimmed milk concentration, comprising an ultrafiltration membrane unit, a pipeline unit and a pressurizing unit; It is characterized in that The ultrafiltration membrane unit comprises a tube body (1) arranged in a vertical state and membrane filaments (2) arranged in the tube body (1); the tube body (1) has a first inlet (11) and a second inlet (12) connected to the pipeline unit for introducing skimmed milk; the first inlet (11) and the second inlet (12) are arranged at positions close to the upper end and the lower end of the tube body (1), respectively; the tube body (1) also has a discharge port (13) connected to the pipeline unit for discharging skimmed milk; the discharge port (13) is arranged at the upper end of the tube body (1); a plurality of coaxial membrane filaments (2) are arranged in the tube body (1); the membrane filaments (2) are tubular structures with micropores; The tube body (1) is provided with a cylinder (3) to which all the membrane threads (2) are fixedly connected, and a filtering area (21) is formed between the cylinder (3) and all the membrane threads (2). A driving assembly (4) for driving the cylinder (3) to move is provided in the tube body (1) and at the positions of the first inlet (11) and the second inlet (12). The upper end and the lower end of the cylinder (3) are respectively provided with an upper end cover (31) and a lower end cover (32) which are drivingly connected to the corresponding driving assembly (4), and the discharge port (13) is provided with a conduit (131) which passes through the upper end cover (31) and extends to the filtering area (21).

2. The ultrafiltration membrane system for skimmed milk concentration according to claim 1, characterized in that: An upper sealing ring (311) tightly fitted with the upper end cover (31) and a lower sealing ring (321) tightly fitted with the lower end cover (32) are fixedly provided in the tube body (1). A gap is left between the upper sealing ring (311) and the lower sealing ring (321) for the cylinder body (3) to move therein. When skimmed milk is introduced into the first inlet (11) and the second inlet (12) at the same time, the skimmed milk enters the membrane filament (2) and permeates into the filtering area (21).

3. The ultrafiltration membrane system for skimmed milk concentration according to claim 2, characterized in that: A guide shaft (132) is fixedly provided at the lower end of the tube body (1) and passes through the lower end cover (32) and extends into the filtering area (21); the guide shaft (132) is coaxial with the cylinder body (3); the upper end cover (31) and the lower end cover (32) respectively have guide sleeves (312) slidably sleeved on the guide tube (131) and the guide shaft (132); an extended end of the guide shaft (132) is close to the guide tube (131); and the driving assembly (4) comprises a rotation driver (41) for driving the cylinder body (3) to rotate and a vibration driver (42) for driving the cylinder body (3) to vibrate up and down during the rotation of the cylinder body (3).

4. The ultrafiltration membrane system for skimmed milk concentration according to claim 3, characterized in that: The rotary driver (41) comprises an impeller (411) coaxial with and rotatably connected to the tube body (1), and a clamping strip (412) arranged on the impeller (411) and extending in the direction of the cylinder body (3). The guide sleeves (312) of the upper end cover (31) and the lower end cover (32) are both fixedly sleeved with an annular sleeve (313). Each of the annular sleeves (313) is provided with a clamping groove along its axial direction for sliding clamping of the corresponding clamping strip (412). An impeller (411) is provided at the position of the first inlet (11) and the second inlet (12). When skimmed milk is simultaneously introduced into the first inlet (11) and the second inlet (12) and impacts the impeller (411), all the impellers (411) are in a rotating state, so that the upper end cover (31) and the lower end cover (32) are in a synchronous rotating state under the cooperation of the clamping strip (412) and the clamping groove, thereby causing the bubbles attached to the membrane filaments (2) to be detached.

5. The ultrafiltration membrane system for skimmed milk concentration according to claim 4, characterized in that: The guide shaft (132) is capable of rotating in the tube body (1). The tube body (1) is provided with a motor for driving the guide shaft (132) to rotate in the opposite direction to the cylinder body (3). The portion of the guide shaft (132) extending into the filtering area (21) is spirally wound with a dividing strip (1321). When the guide shaft (132) and the cylinder body (3) rotate synchronously and in the opposite direction, the separated bubbles are in a ruptured state under the stirring of the dividing strip (1321).

6. The ultrafiltration membrane system for skimmed milk concentration according to claim 5, characterized in that: The guide shaft (132) is provided with an air passage (1322) from its lower end along its axial direction for allowing hot air to pass through. When hot air passes through the air passage (1322) of the guide shaft (132), the guide shaft (132) is in a heated state, thereby reducing the viscosity of the skimmed milk and thereby reducing the filtration resistance of the membrane filaments (2).

7. The ultrafiltration membrane system for skimmed milk concentration according to claim 3, characterized in that: The vibration driver (42) comprises a movable portion (422) fixedly arranged on the guide sleeve (312) of the lower end cover (32) and a fixed portion (421) fixedly arranged on the tube body (1); the fixed portion (421) is located below the movable portion (422); the fixed portion (421) and the movable portion (422) are both annular structures; the upper surface of the fixed portion (421) comprises a convex point (4211); the lower surface of the movable portion (422) comprises a plurality of convex blocks (4221) uniformly distributed around its circumference; when the cylinder (3) rotates, all the convex blocks (4221) continuously pass through the convex points (4211), so that the cylinder (3) is in a state of up and down vibration, thereby causing dirt inside the membrane filaments (2) to fall off when the membrane filaments (2) are backwashed.

8. The ultrafiltration membrane system for skimmed milk concentration according to claim 7, characterized in that: The convex point (4211) is specifically a ball that is in rolling contact with the lower surface of the movable part (422), and the upper surface of the fixed part (421) is evenly distributed with a plurality of the ball bearings along its circumferential direction, and each convex block (4221) has an inclined surface at one end passing through the ball bearing.

9. The ultrafiltration membrane system for skimmed milk concentration according to claim 4, characterized in that: A spring (423) is provided between each ring sleeve (313) and the corresponding impeller (411) to provide a buffer during the vibration of the cylinder (3).

10. The ultrafiltration membrane system for skimmed milk concentration according to claim 1, characterized in that: A support portion (14) is provided between the tube body (1) and the cylinder body (3) for maintaining the two coaxially; the support portion (14) is a spherical structure; and grooves for embedding the support portion (14) are provided on both the tube body (1) and the cylinder body (3).

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