Membrane filter, and a membrane filtration assembly including such a membrane filter

Abstract

The present invention relates to a membrane filter (2) for providing pure water. The membrane filter (2) includes an evaporation chamber (7), a condensation chamber (8), and a membrane (9) that separates the evaporation chamber (7) and the condensation chamber (8) and has a pore diameter of 1000 nanometers or less. The membrane (9) is a multilayer polymer membrane including a non-woven first layer (46) and a spunbonded second layer (47). The non-woven first layer (46) has a pore diameter of 1000 nanometers or less, and the spunbonded second layer (47) is laminated on the first layer (46) and faces the condensation chamber (8).

Description

Technical Field

[0001] The present invention generally relates to a membrane filtration assembly configured to remove particles from water, i.e., to produce pure water, and more particularly to a membrane filter used in industrial applications and configured to produce pure water. More specifically, the present invention relates to a membrane filtration assembly capable of producing nano / ultra-purified water that does not contain particles larger than 10 nanometers.

[0002] The present invention is particularly related to a membrane filter that includes an evaporation chamber, a condensation chamber, and a membrane that separates the evaporation chamber and the condensation chamber, and the membrane has a pore size of 1000 nanometers or less.

[0003] The present invention is also related to a membrane filtration assembly for providing pure water. The membrane filtration assembly includes a membrane filter configured to produce pure water, having an evaporation chamber and a condensation chamber, wherein the evaporation chamber and the condensation chamber are separated from each other by a membrane, and the membrane has a pore size of 1000 nanometers or less; a water storage tank connected to the membrane filter for intermediate storage of pure water; a water supply unit connected to the membrane filter; a pure water dispenser tool connected to the water storage tank; and includes.

[0004] Such membrane filters and membrane filtration assemblies are particularly useful in the semiconductor manufacturing industry, where semiconductor wafers pass through multiple cleaning steps using pure water.

Background Art

[0005] The present invention is based on the fact that while the semiconductor is getting smaller, in order to meet the demand for an electronic device that consumes less energy, is faster, and is cheaper. Thus, in order to include more semiconductors / structures per wafer, the semiconductors / structures on the silicon wafer become smaller, and the distance between the structures also becomes smaller. Thus, in order to avoid short circuits or failures of the semiconductor, there is an increasing need to more efficiently wash away similarly small contaminants from the wafer, and it is necessary to use ultrapure water for the washing water so as not to contaminate the wafer with the washing water. Although the washing of the wafer consumes a large amount of ultrapure water to obtain the required washing result, the production of ultrapure water takes time and energy, and the useful life of the ultrapure water is short, that is, shorter than 30 minutes. Thus, the conveyance of ultrapure water by a tank or pipeline causes contamination, that is, contamination is caused by the growth of existing contaminants and by the increase of contaminants from the materials of the tank / pipeline. The conventional membrane filtration assembly cannot produce the required amount of pure water because it is too slow in the prior art.

[0006] Also, the prior art has a problem in that the membrane is connected / welded to its carrier / frame to obtain a sealed relationship between the evaporation chamber and the condensation chamber. Thus, if the membrane is not perfectly connected / welded to the carrier / frame when the membrane is attached to the membrane filter, leakage can occur if the membrane is distorted or wrinkled.

[0007] Thus, there is a need for equipment configured to efficiently produce a large amount of ultrapure water at the location of use, that is, near the cleaning station in the clean room. Pure water can be used as a solvent in different industrial applications in addition to being used as a detergent. SUMMARY OF THE INVENTION

[0008] (Object of the present invention) The aim of the present invention is to overcome the drawbacks and disadvantages of conventional membrane filters and membrane filtration assemblies and to provide an improved membrane filter and membrane filtration assembly. The main object of the present invention is to provide a membrane filter and membrane filtration assembly of the initially defined type, which is improved and which always provides the required amount of pure water and is available in the clean room of a semiconductor / wafer manufacturing plant. Another object of the present invention is to provide a membrane filter and membrane filtration assembly that enables the simultaneous and continuous production and use of pure water. Another object of the present invention is to provide a membrane filter and membrane filtration assembly in which the required amount of pure water is reduced due to an increase in the degree of purification of the pure water. Another object of the present invention is to provide a membrane filter and membrane filtration assembly that consumes less tap water. Another object of the present invention is to provide a membrane filter and membrane filtration assembly in which the membrane is more easily fixed in the membrane filter.

[0009] (Summary of the Invention) Based on the present invention, at least one main object is achieved by the initially defined membrane filter and membrane filtration assembly having the features defined by the independent claims. Preferred embodiments of the present invention are further defined by the dependent claims.

[0010] Based on the present invention, there is provided a membrane filter and membrane filtration assembly of the initially defined type, in which the membrane is a multilayer polymer membrane comprising a non-woven first layer and a spunbonded second layer, the non-woven first layer having a pore size of 1000 nanometers or less, and the spunbonded second layer being laminated to the first layer and facing the condensation chamber.

[0011] Therefore, the present invention is based on the insight of newly designing / constructing a membrane, and this membrane guarantees the ability to increase the production amount of pure water and produce pure water without problems. More precisely, the innovative multilayer membrane brings a higher output without compromising the required purification degree, and the spunbonded second layer ensures that there is always a distance between the first layer of the membrane and the surface / wall in the condensation chamber. Since the pressure in the evaporation chamber is higher than that in the condensation chamber, the contact between the filtration layer of the membrane, i.e., the first layer, and the wall of the condensation chamber has an adverse effect on the production amount of purified water.

[0012] Based on various embodiments of the present invention, the first layer of the membrane contains a fluoropolymer, and the second layer of the membrane contains a thermoplastic polymer. Therefore, the first layer / filtration layer of the membrane surely has hydrophobicity and can be optimized to obtain the required purification degree, and the second layer of the membrane can be optimized to provide a stable structure that prevents the contact between the first layer and the wall of the condensation chamber. More precisely, the second layer always provides a volume where the vapor from the evaporation chamber can condense without being compressed.

[0013] Based on various embodiments of the present invention, the membrane filter includes a cooling chamber located in the vicinity of the condensation chamber. Therefore, appropriate and efficient cooling in the condensation chamber is achieved.

[0014] Based on various embodiments of the present invention, the membrane filter includes a film that separates the cooling chamber and the condensation chamber. Also, the thickness of the film is 0.08 millimeters or more and 0.25 millimeters or less. Therefore, appropriate and efficient cooling in the condensation chamber is achieved, and the film is appropriately connected / welded to its carrier / frame. If the film is thin, it becomes very difficult / impossible to connect / weld to the carrier / frame, and if the film is thick, the cooling efficiency decreases.

[0015] Further features and advantages of the present invention will become apparent from other dependent claims and the detailed description of the following preferred embodiments.

[0016] The features and advantages of the present invention described above, and a more complete understanding of other features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0017]

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Modes for Carrying Out the Invention

[0018] First, reference is made to FIG. 1, which shows a schematic diagram of the main components of a membrane filtration assembly generally designated by reference numeral 1.

[0019] The membrane filtration assembly 1 includes a membrane filter 2 configured to produce pure water such as ultrapure water, a water supply unit 3 connected to the membrane filter 2 and configured to supply water to be treated by the membrane filter 2, a water storage tank 4 connected to the membrane filter 2 and configured to receive pure water from the membrane filter 2, and a pure water dispenser tool 5 connected to the water storage tank 4. The water storage tank 4 is configured to store pure water intermediate / temporarily.

[0020] The water supply unit 3 is connected to a water source 6 such as a water mains of a water supply, i.e., connected to tap water. The pure water dispenser tool 5 may be a manual nozzle / handle or an automatically controlled nozzle.

[0021] The membrane filter 2 includes a sealed evaporation chamber 7 and a sealed condensation chamber 8, and the evaporation chamber 7 and the condensation chamber 8 are separated by a membrane 9. The condensation chamber 8 is also known as a gas chamber. Based on various embodiments, the membrane filter 2 includes a plurality of sets of evaporation chambers 7 and condensation chambers 8, and such sets are connected in parallel. Preferably, each evaporation chamber 7 is associated with two condensation chambers 8, and these two condensation chambers 8 are provided on each side of the evaporation chamber 7 and are provided to face each other. The membrane 9 has a pore size of 1000 nanometers or less, preferably a pore size of 750 nanometers or less, and more preferably a pore size of 500 nanometers or less. The membrane 9 has a pore size of 100 nanometers or more. Generally, a relatively small pore size can provide clean water, but the production of pure water is slowed down. In order to prevent liquid penetration, the pores should be made small enough.

[0022] The water supply unit 3 supplies water to the evaporation chamber 7, that is, the evaporation chamber 7 is filled with hot water. For example, the evaporation chamber 7 is filled with hot water at 80°C or higher and 90°C or lower. Such water cannot pass through the membrane 9, but the steam at the boundary between the water and the membrane 9 passes through the membrane 9 leaving contaminants in the evaporation chamber 7 and enters the condensation chamber 8. The temperature in the condensation chamber 8 is lower than the temperature in the evaporation chamber 7. That is, the condensation chamber 8 is cooled, and in the condensation chamber 8, the steam accumulates / condenses into droplets. The condensation chamber 8 includes a cold surface 10, and efficient condensation occurs on the cold surface 10. The droplets accumulate and finally flow to the bottom of the condensation chamber 8, and the pure water leaves the membrane filter 2 at the bottom and enters the water storage tank 4. The pressure difference between the evaporation chamber 7 and the condensation chamber 8 is 0.5 bar or less, that is, the water is not forced / pressurized to pass through the membrane 9.

[0023] The membrane 9 should be made of a thermally and chemically stable material, such as materials like polytetrafluoroethylene (PTFE), polypropylene (PP), polyvinylidene fluoride (PVDF), etc.

[0024] The water storage tank 4 includes at least one tank 11a for storing pure water intermediate / temporarily. Hereinafter, the water storage tank 4 includes at least two tanks 11a, 11b, but the present invention is not limited to the water storage tank 4 including two tanks 11a, 11b. The tanks 11a, 11b are connected in parallel between the membrane filter 2 and the pure water dispenser tool 5. During the operation of the membrane filtration assembly 1, the first tank 11a is filled with pure water from the membrane filter 2 and the second tank 11b provides pure water to the dispenser tool 5, or the second tank 11b is filled with pure water from the membrane filter 2 and the first tank 11a provides pure water to the dispenser tool 5. Thus, the water storage tank supplies ultrapure water in time for the place of use. That is, the two aforementioned tanks are filled alternately and supply ultrapure water to the dispenser tool alternately. Thus, the production and utilization of pure water can be carried out simultaneously and continuously.

[0025] Note that the first tank 11a does not need to be completely filled before the pure water in it is used, nor does it need to use up all the pure water in it before filling. Preferably, the first tank 11a is filled to the same extent / scope as the demand for pure water by the dispenser tool 5 over the time required to fill the second tank 11b.

[0026] The pure water used during wafer cleaning etc. may be collected in the gutter / drain device 12, returned to the water source 6, and recycled. The gutter / drain device 12 may include a suitable filter to prevent contaminants / substances that have entered the water during the cleaning step from reaching the water source 6. The membrane filtration assembly 1 may include a prefilter located between the water source 6 and the water supply unit 3.

[0027] Reference is made to FIG. 2 showing a schematic view of the water storage tank 4 of the membrane filtration assembly 1 based on the first embodiment.

[0028] Based on various embodiments, each of the tanks 11a, 11b includes an intermediate pipe 13 and an outlet pipe 15. The intermediate pipe 13 is connected to the membrane filter 2 and has a controllable intermediate valve 14. The outlet pipe 15 is connected to the pure water dispenser tool 5 and has a controllable outlet valve 16. Thus, the separate tanks of the water storage tank 4 can be filled or emptied individually. The tanks 11a, 11b are provided such that pure water automatically flows into the outlet pipe 15, and the outlet pipe 15 is connected to the tank at the lowest point of the tank.

[0029] In the event that the pure water in the tank 11a cannot be used up within the time, that is, before the useful life of the pure water in the first tank 11a ends and / or before the second tank 11b is full, what remains in the first tank 11a is discharged / wasted before the pure water in the second tank 11b is used. This discharge / waste may be a manual operation that directs the dispenser tool 5 directly towards the drain / wastewater device 12. The same operation is also applicable to the water storage tank 4 having only one tank 11a. Thus, any old / inappropriate water in separate tanks can be discharged or recycled without affecting the supply of pure water to the dispenser tool.

[0030] Reference is made to FIG. 3 showing a schematic view of the water storage tank 4 of the membrane filtration assembly 1 according to the second embodiment.

[0031] Based on various embodiments, each of the tanks 11a, 11b includes a discharge / waste pipe 17, and the discharge / waste pipe 17 has a controllable discharge valve 18 and bypasses the dispenser tool 5. In this way, the discharge / waste of what remains in one of the tanks 11a, 11b is automatically executed, and at the same time, the pure water in the other of the tanks 11a, 11b can be used by the dispenser tool 5. The discharge pipe 17 is preferably connected directly or indirectly via the drain / wastewater device 12 to the water source 6. The same configuration is also applicable to the water storage tank 4 having only one tank 11a.

[0032] When tanks 11a and 11b become empty, it is important that no residue remains in the tanks because the residue in the tanks may contaminate the pure water of the next batch. Based on various embodiments, the membrane filtration assembly 1 includes a gas source 19, preferably a gas source 19 of a gas such as nitrogen. Each of the tanks 11a and 11b includes an air supply pipe 20, and the air supply pipe 20 is connected to the gas source 19 and has a controllable gas valve 21. The pressurized gas from the gas source 19 is utilized to empty the tanks 11a and 11b via the outlet valve 16 and / or the discharge valve 18. The air supply pipe 20 is preferably connected to the tanks 11a and 11b in the vicinity of the intermediate pipe 13 or via the intermediate pipe 13, downstream of the intermediate valve 14.

[0033] Reference is also made to FIG. 4 showing a schematic view of the water supply unit 3 of the membrane filtration assembly 1 here.

[0034] Based on various embodiments, the water supply unit 3 includes a primary water supply pipe generally designated by reference numeral 22, and the primary water supply pipe 22 is connected to the evaporation chamber 7 of the membrane filter 2 and includes a heater 23. Thus, the water supplied to the evaporation chamber 7 is preheated to a suitable / accurate temperature when it reaches the evaporation chamber.

[0035] The primary water supply pipe 22 includes a water conditioner 24, and the water conditioner 24 is configured to control the flow rate and pressure of the water supplied to the evaporation chamber 7 via the primary water supply pipe 22. The water conditioner 24 is preferably formed by a pump, and the pump operates automatically so that the pressure in the evaporation chamber 7 does not become too high.

[0036] Based on various embodiments, the water supply unit 3 includes a buffer tank 25 connected to the primary water supply pipe 22. Preferably, the buffer tank 25 is associated with the heater 23, but the buffer tank 25 and the heater 23 may be located in series with each other. Further, the water supply pipe 26 is connected to the buffer tank 25 or the water conditioner 24 and is configured to be connected to the water source 6. The water supply pipe 26 includes a controllable filling valve 27 for filling the buffer tank 25 or operating the water conditioner 24. Based on various embodiments, the water supply unit 3 includes a primary return water pipe 28 extending from the evaporation chamber 7 to the buffer tank 25. The water that has not been purified in the membrane filter 2, that is, the water that has not passed through the membrane 9, is returned / recycled, and such water is beneficial because it is already at a high temperature. The buffer tank 25 preferably includes a level sensor for controlling the filling valve 27. The primary water supply pipe 22 preferably includes an air vent structure.

[0037] The water supply unit 3 includes a pressure regulating valve 29 so that the pressure on the upstream side of the water conditioner 24 does not become too high. The pressure regulating valve 29 may be located between the water source 6 and the water supply unit 3.

[0038] The flow rate generated by the water conditioner 24 is in the range of 1 liter / minute to 5 liters / minute, and the production amount of pure water reaching the water storage tank 4 is in the range of 1 liter / minute to 4 liters / minute.

[0039] Based on various embodiments, the membrane filter 2 includes a sealed cooling chamber 30 located in the vicinity of the condensation chamber 8. Thus, the cooling chamber 30 is configured to provide a cold surface 10. Preferably, the membrane filter 2 includes a film / partition / foil 31 separating the cooling chamber 30 and the condensation chamber 8, that is, the cold surface 10 is part of the film / partition 31. The cooling chamber 30 contains liquid / water or gas. Alternatively, the cold surface 10 is part of a cooling block / cooling device.

[0040] Based on various embodiments, the thickness of the film 31 is 0.08 millimeters or more and 0.25 millimeters or less, preferably 0.1 millimeters or more and 0.2 millimeters or less. Thus, the film 31 is resistant to deformation and easy to attach, while still having low heat insulation properties. The cold surface 10 should be as smooth as possible to promote the flow of pure water downward. Preferably, the film 31 is a hydrophobic material, preferably including a fluoropolymer such as polyvinylidene fluoride (PVDF).

[0041] Based on various embodiments, the water supply unit 3 includes a secondary water supply pipe generally designated by reference numeral 32, and the secondary water supply pipe 32 is connected to the cooling chamber 30 of the membrane filter 2 and includes a cooler 33. Thus, the water in the cooling chamber 30 has a temperature suitable for efficiently condensing the water vapor in the condensation chamber 8 into pure water.

[0042] The secondary water supply pipe 32 includes a water conditioner 34, and the water conditioner 34 is configured to control the flow rate and pressure of the water supplied to the cooling chamber 30 via the secondary water supply pipe 32. The water conditioner 34 is preferably formed by a pump, and the pump operates automatically so that the pressure in the cooling chamber 30 does not become too high.

[0043] Based on various embodiments, the water supply unit 3 includes a buffer tank 35 connected to the secondary water supply pipe 32. Preferably, the buffer tank 35 is associated with the cooler 33, but the buffer tank 35 and the cooler 33 may be located in series with each other. Also, the water supply pipe 36 is connected to the buffer tank 35 or the water conditioner 34 and is configured to be connected to the water source 6. The water supply pipe 36 includes a controllable filling valve 37 to fill the buffer tank 35 or supply water to the water conditioner 34. Based on various embodiments, the water supply unit 3 includes a secondary return pipe 38 extending from the cooling chamber 30 to the buffer tank 35. The cooling water is returned / recycled, and such water is beneficial for reducing the water usage.

[0044] The buffer tank 35 preferably includes a water level sensor to control the filling valve 37. The secondary water supply pipe 32 preferably includes an air venting structure.

[0045] Preferably, the cooler 33 is a thermoelectric heat pump, for example, it may be a Peltier device that transfers heat from one side of the element to the other using electricity. Heat is transferred from the liquid / water in the secondary water supply pipe 32, preferably in the buffer tank 35, to the surrounding air. Based on an alternative embodiment, such a thermoelectric heat pump is directly related to the cooling chamber 30.

[0046] Preferably, at least the pipes extending from the water storage tank 4 and the condensation chamber 8 to the dispenser tool 5 are treated so that the surface facing the pure water has hydrophobicity to promote the flow of pure water.

[0047] Reference is made to FIGS. 5 to 7 showing a schematic diagram of the schematic membrane filter 2. The membrane filter 2 includes different stacked configurations / elements to provide an evaporation chamber 7, a condensation chamber 8, and a cooling chamber 30. However, preferably, the stacked membrane filter 2 may include a plurality of such combinations installed in parallel with each other. Preferably, in order to minimize heat radiation to the surrounding environment / clean room, the top set and the bottom set in the stacked configuration include the cooling chamber 30.

[0048] Based on the disclosed schematic embodiment, the stacked membrane filter 2 preferably includes a first end plate 39 made of metal, an elastic first gasket 40, a membrane 9, a rigid first polymer frame 41, an elastic second gasket 42, a rigid second polymer frame 43, a film 31, an elastic third gasket 44, and a second end plate 45 preferably made of metal.

[0049] Based on the disclosed embodiment, the first end plate 39 separates the evaporation chamber 7, and the second end plate 45 separates the cooling chamber 30. That is, the end plates separate the external / adjacent chambers.

[0050] Based on the present invention, the membrane 9 is a multilayer polymer membrane including a non-woven first layer 46 and a spunbonded second layer 47. The non-woven first layer 46 has a pore diameter of 1000 nanometers or less, and the spunbonded second layer 47 is laminated on the first layer 46 and faces the condensation chamber 8. Thus, the first layer 46 faces the evaporation chamber 7. Based on various embodiments, the thickness of the membrane 9 is 0.1 millimeter or more and 0.4 millimeter or less, preferably 0.2 millimeter or more and 0.3 millimeter or less. Thus, the first layer 46 of the membrane 9 is the actual filtration layer. The first layer 46 of the membrane 9 preferably includes a fluoropolymer such as polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF). The second layer 47 of the membrane 9 preferably includes a thermoplastic polymer such as polypropylene (PP). The first layer 46 and the second layer 47 are manufactured separately before being laminated in order to minimize the blockage of the pores of the first layer 46 by minimizing the intrusion of the second layer 47 into the first layer 46.

[0051] The rigid polymer frames / carriers 41, 43 preferably include a rigid fluoropolymer such as polyvinylidene fluoride (PVDF), and the elastic gaskets 40, 42, 44 preferably include an elastic fluoropolymer such as polytetrafluoroethylene (PTFE). The rigid polymer frames 41, 43 maintain their initial thickness even when the membrane filter 2 is attached / compressed. The elastic gaskets 40, 42, 44 have a thickness smaller than the initial thickness in response to the attachment / compression of the membrane filter 2. The elastic gasket is preferably compressed to 25% or more and 40% or less of the initial thickness / unloaded thickness. If the compression rate is too small, there is a risk of leakage. If the compression rate is too large, the reduced gasket loses its sealing / elastic properties and there is a risk of leakage. When the stacked membrane filters 2 are attached / compressed, the first end plate 39 and the second end plate 45 are clamped together, and a distance element has an appropriate length between the end plates to prevent excessive clamping. Thus, the appropriate length of the distance element is equal to the sum of the final / compressed thickness of the gasket and the thickness of the polymer frame.

[0052] The first polymer frame 41 includes a first surface 48, a second surface 49, and a central opening 50 extending between the first surface 48 and the second surface 49, and at least a part of the condensation chamber 8 is constituted by the central opening 50. The membrane 9 is connected / welded to the first surface 48 of the first polymer frame 41, the first surface 48 covers the central opening, and the second layer 47 of the membrane 9 faces the first surface 48 of the first polymer frame 41. The membrane 9 can be connected to the first polymer frame 41 by other suitable means such as an adhesive, but welding (ultrasonic welding) is preferred. The second layer 47 of the membrane 9 facilitates the connection between the membrane 9 and the first polymer frame 41. Thus, the first layer / filter layer 46 of the membrane 9 does not need to be optimized for connection / welding to the first polymer frame 41. Instead, the second layer 47 of the membrane 9 is optimized for connection / welding to the first polymer frame 41, and the first layer 46 of the membrane 9 is optimized for filtration.

[0053] The second polymer frame 43 includes a first surface 51, a second surface 52, and a central opening 53 extending between the first surface 51 and the second surface 52. The film 31 is connected / welded to one of the first surface 51 covering the central opening in the second polymer frame 43 and the second surface 52 covering the central opening in the second polymer frame 43. The film 31 can be connected to the second polymer frame 43 by other suitable means such as an adhesive, but welding (ultrasonic welding) is preferred. When the film 31 is connected to the second surface 52 of the second polymer frame 43 (see FIG. 6), the central opening 53 constitutes at least a part of the condensation chamber 8. When the film 31 is connected to the first surface 51 of the second polymer frame 43 (see FIG. 7), the central opening 53 constitutes at least a part of the cooling chamber 30.

[0054] The elastic first gasket 40 includes a first surface 54, a second surface 55, and a central opening 56 extending between the first surface 54 and the second surface 55, and at least a part of the evaporation chamber 7 is constituted by the central opening 56. An inlet 57 which is a part of the primary water supply pipe 22 extends into the central opening 56 at the lower part of the first gasket 40, and an outlet 58 which is a part of the primary water return pipe extends from the central opening 56 at the upper part of the first gasket 40.

[0055] The elastic second gasket 42 includes a first surface 59, a second surface 60, and a central opening 61 extending between the first surface 59 and the second surface 60, and at least a part of the condensation chamber 8 is constituted by the central opening 61. An outlet 62 which is a part of the intermediate pipe 13 extends from the central opening 61 at the lower part of the second gasket 42. The second gasket 42 may include a venting structure 63 to prevent an increase in the pressure inside the condensation chamber 8.

[0056] The resilient third gasket 44 includes a first surface 64, a second surface 65, and a central opening 66 extending between the first surface 64 and the second surface 65, and at least a part of the cooling chamber 30 is constituted by the central opening 66. The inlet 67, which is part of the secondary water supply pipe 32 and the primary water supply pipe 22, extends into the central opening 66 at the upper part of the third gasket 44, and the outlet 68, which is part of the secondary water return pipe 38, extends from the central opening 66 at the lower part of the third gasket 44.

[0057] Reference is made to FIGS. 8 - 15 showing another schematic view of the schematic membrane filter 2. Only the content added to the schematic embodiments of FIGS. 5 - 7 / the content different from the schematic embodiments of FIGS. 5 - 7 will be described.

[0058] Based on various embodiments, the membrane filter 2 includes a primary water supply manifold 69 that extends between the first surface 54 and the second surface 55 of the first gasket 40 at the lower part of the first gasket 40, and the inlet 57 extends from the primary water supply manifold 69 into the central opening 56 of the first gasket 40. The primary water supply manifold 69 is part of the primary water supply pipe 22 and extends outside the membrane filter 2 from the first gasket 40, for example, extending to the outer surface 70 of the first end plate 39 through any intermediate element. The primary water supply manifold 69 may extend through the entire membrane filter 2, that is, it may extend from the outer surface 70 of the first end plate 39 to the outer surface 71 of the second end plate 45. Preferably, all the evaporation chambers 7 are connected to the primary water supply manifold 69.

[0059] Based on various embodiments, the membrane filter 2 includes a primary return manifold 72 that extends between a first surface 54 and a second surface 55 of the first gasket 40 at the upper part of the first gasket 40, and the outlet 58 extends from the central opening 56 of the first gasket 40 to the primary return manifold 72. The primary return manifold 72 is part of the primary return pipe 28 and extends from the first gasket 40 to the outside of the membrane filter 2, for example, extending to the outer surface 70 of the first end plate 39 through any intermediate element. The primary return manifold 72 may extend through the entire membrane filter 2, that is, it may extend from the outer surface 70 of the first end plate 39 to the outer surface 71 of the second end plate 45. Preferably, all evaporation chambers 7 are connected to the primary return manifold 72.

[0060] Based on various embodiments, the membrane filter 2 includes a pure water manifold 73 that extends between a first surface 59 and a second surface 60 of the second gasket 42 at the lower part of the second gasket 42, and the outlet 62 extends from the central opening 61 of the second gasket 42 to the pure water manifold 73. The pure water manifold 73 is part of the intermediate pipe 13 and extends from the second gasket 42 to the outside of the membrane filter 2, for example, extending to the outer surface 70 of the first end plate 39 through any intermediate element. The pure water manifold 73 may extend through the entire membrane filter 2, that is, it may extend from the outer surface 70 of the first end plate 39 to the outer surface 71 of the second end plate 45. Preferably, all condensation chambers 8 are connected to the pure water manifold 73. The pure water manifold 73 is preferably coated / lined with a hydrophobic material, and the hydrophobic material preferably includes a fluoropolymer such as polyvinylidene fluoride (PVDF) to ensure that pure water leaves the membrane filter 2. The coating / lining extending along the entire pure water manifold 72 eliminates the risk of clogging at the boundaries between different frames and gaskets. The coating / lining shall not block the outlet 62 extending from the condensation chamber 8 to the pure water manifold 73.

[0061] Based on various embodiments, the membrane filter 2 includes a vent manifold 74 that extends between a first surface 59 and a second surface 60 of the second gasket 42 at the upper portion of the second gasket 42, and an air vent structure 63 extends from a central opening 61 of the second gasket 42 to the vent manifold 74. The vent manifold 74 extends from the second gasket 42 to the outside of the membrane filter 2, for example, extending to the outer surface 70 of the first end plate 39 through any intermediate element. The vent manifold 74 may extend through the entire membrane filter 2, that is, it may extend from the outer surface 70 of the first end plate 39 to the outer surface 71 of the second end plate 45. Preferably, all condensation chambers 8 are connected to the vent manifold 74.

[0062] Based on various embodiments, the membrane filter 2 includes a second water supply manifold 75 that extends between a first surface 64 and a second surface 65 of the third gasket 44 at the upper portion of the third gasket 44, and an inlet 67 extends from a central opening 66 of the third gasket 44 to the second water supply manifold 75. The second water supply manifold 75 is a part of the second water supply pipe 32 and extends from the third gasket 44 to the outside of the membrane filter 2, for example, extending to the outer surface 71 of the second end plate 45 through any intermediate element. The second water supply manifold 75 may extend through the entire membrane filter 2, that is, it may extend from the outer surface 70 of the first end plate 39 to the outer surface 71 of the second end plate 45. Preferably, all cooling chambers 30 are connected to the second water supply manifold 75.

[0063] Based on various embodiments, the membrane filter 2 includes a second return manifold 76 that extends between a first surface 64 and a second surface 65 of the third gasket 44 at the lower part of the third gasket 44, and the outlet 68 extends from a central opening 66 of the third gasket 44 to the second return manifold 76. The second return manifold 76 is part of the second return pipe 38 and extends from the third gasket 44 to the outside of the membrane filter 2, for example, extends to the outer surface 71 of the second end plate 45 through any intermediate element. The second return manifold 76 may extend through the entire membrane filter 2, that is, it may extend from the outer surface 70 of the first end plate 39 to the outer surface 71 of the second end plate 45. Preferably, all cooling chambers 30 are connected to the second return manifold 76.

[0064] Figures 9 to 15 show different elements of the membrane filter 2 based on Figure 8, and these elements are viewed from the first surface 70 of the first end plate 39.

[0065] Figure 10 shows the first gasket 40. The opening of the inlet 57 in the central opening 56 is located at one of the lower corners, and the opening of the outlet 58 in the central opening 56 is located at the upper corner directly opposite to obtain an optimal distribution of water / heat throughout the evaporation chamber 7. Preferably, the cross-sectional area of the inlet 57 is smaller than the cross-sectional area of the primary feed manifold 69, preferably smaller than 50% of the cross-sectional area of the primary feed manifold 69. Preferably, the inlet 57 includes a curved portion between the primary feed manifold 69 and the central opening 56. Preferably, the cross-sectional area of the outlet 58 is smaller than the cross-sectional area of the primary return manifold 72, preferably smaller than 50% of the cross-sectional area of the primary return manifold 72. Preferably, the outlet 57 includes a curved portion between the primary return manifold 72 and the central opening 56.

[0066] Figure 12 shows the second gasket 42. The opening of the outlet 62 in the central opening 61 is located in the middle of the bottom, and the opening of the air vent structure 63 in the central opening 61 is located in the middle of the top to obtain an optimal discharge of pure water from the condensation chamber 8.

[0067] Figure 14 shows the third gasket 44. The opening of the inlet 67 in the central opening 66 is located at one of the upper corners, and the opening of the outlet 68 in the central opening 66 is located at the lower corner directly opposite to obtain an optimal distribution of water / heat throughout the cooling chamber 30. Preferably, the cross-sectional area of the inlet 67 is smaller than the cross-sectional area of the secondary feed water manifold 75, and preferably smaller than 50% of the cross-sectional area of the secondary feed water manifold 75. Preferably, the inlet 67 includes a curved portion between the secondary feed water manifold 75 and the central opening 66. Preferably, the cross-sectional area of the outlet 68 is smaller than the cross-sectional area of the secondary return water manifold 76, and preferably smaller than 50% of the cross-sectional area of the secondary return water manifold 76. Preferably, the outlet 67 includes a curved portion between the secondary return water manifold 76 and the central opening 66.

[0068] The primary feed water manifold 69 and the secondary return water manifold 76 are preferably located at one of the lower corners of the membrane filter 2 respectively, and the primary return water manifold 72 and the secondary feed water manifold 75 are preferably located at one of the upper corners of the membrane filter 2 respectively.

[0069] (Possible variations) The present invention is not limited to the embodiments described above and shown in the drawings, and these descriptions and embodiments are for illustrative purposes only. This patent application intends to cover all variations and modifications of the preferred embodiments described herein. Therefore, the present invention is defined by the language of the appended claims. Thus, the device can be varied in all ways conceivable within the framework of the appended claims.

[0070] Also, it should be noted that all information related to terms such as up, down, above, below, etc. must be interpreted / decoded considering the device positioned in the direction in which the reference numbers can be correctly read in the drawings. Thus, such terms only indicate the relative relationships in the illustrated embodiments, and this relationship can be changed when another structure / design is provided for the device according to the present invention.

[0071] Also, it should be noted that even if it is not explicitly stated that the features of a specific embodiment can be combined with the features of another embodiment, if the combination is possible, the combination is considered obvious.

Claims

1. A membrane filter (2) for providing pure water, an evaporation chamber (7); a condensation chamber (8); a membrane (9) separating the evaporation chamber (7) and the condensation chamber (8) and having a pore size of 1000 nanometers or less; Including, The membrane (9) is a multilayer polymer membrane comprising a nonwoven first layer (46) and a spunbonded second layer (47), the nonwoven first layer (46) having a pore size of 1000 nanometers or less, the spunbonded second layer (47) being laminated to the first layer (46) and facing the condensation chamber (8); The membrane filter (2) includes a cooling chamber (30) located near the condensation chamber (8), A film (31) separates the cooling chamber (30) from the condensing chamber (8), The thickness of the film (31) is 0.08 mm or more and 0.25 mm or less. Membrane filter.

2. The thickness of the membrane (9) is 0.1 mm or more and 0.4 mm or less, preferably 0.2 mm or more and 0.3 mm or less. The membrane filter according to claim 1.

3. the pore size of the first layer (46) of the membrane (9) is 750 nanometers or less, preferably 500 nanometers or less; The membrane filter according to claim 1 or 2.

4. the first layer (46) of the membrane (9) comprises a fluoropolymer such as polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF); The membrane filter according to claim 1.

5. the second layer (47) of the membrane (9) comprises a thermoplastic polymer such as polypropylene (PP); The membrane filter according to claim 1.

6. The thickness of the film (31) is 0.1 mm or more and 0.2 mm or less. The membrane filter according to claim 1.

7. The film (31) comprises a fluoropolymer such as polyvinylidene fluoride (PVDF). The membrane filter according to claim 1.

8. A membrane filtration assembly (1) for providing pure water, comprising: a membrane filter (2) configured to produce pure water, the membrane filter (2) having an evaporation chamber (7) and a condensation chamber (8), the evaporation chamber (7) and the condensation chamber (8) being separated by a membrane (9); a water tank (4) connected to the membrane filter (2) for temporarily storing pure water; a water supply unit (3) connected to the membrane filter (2); a pure water dispenser tool (5) connected to the water reservoir (4); Including, The membrane (9) is a multilayer polymer membrane comprising a nonwoven first layer (46) and a spunbonded second layer (47), the nonwoven first layer (46) having a pore size of 1000 nanometers or less, the spunbonded second layer (47) being laminated to the first layer (46) and facing the condensation chamber (8); The membrane filter (2) includes a cooling chamber (30) located near the condensation chamber (8), A film (31) separates the cooling chamber (30) from the condensing chamber (8), The thickness of the film (31) is 0.08 mm or more and 0.25 mm or less. Membrane filtration assembly.

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