Exhaust method for hollow fiber membrane filter and hollow fiber membrane filter device

Abstract

A method of venting a hollow fibre membrane filter (1) prior to first use of the filter whereby liquid (21) is forced through the hollow fibre membrane filter (1), the method comprising a shipping package preparation step during which a flexible and liquid-tight shipping package (2) that is liquid-tight sealed along a circumferential surface of a housing (3) of the hollow fibre membrane filter (1) is open at a first end (13) and open at a second end (14) to provide first and second openings (15, 16) of the shipping package (2) with access to corresponding first and second openings (4, 16) at opposite front sides (5, 7) of the housing (3) of the hollow fibre membrane filter (1). Then, during a shipping package filling step, an amount of liquid (21) is filled at the first end (15) into a cavity (22) formed by the shipping package (2) at the first front side (5) of the housing (3) of the hollow fibre membrane filter (1). The cavity (22) is then closed. During a subsequent venting step, the amount of liquid (21) in the closed cavity (22) is forced through the hollow fibre membrane filter (1) to exit at the second front side (7) of the housing (3) of the hollow fibre membrane filter (1) and through the open second end (14) of the shipping package (2).

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for venting a hollow fiber membrane filter prior to first use of the filter. The present invention also relates to a hollow fiber membrane filter device which allows performing the venting method prior to first use of the hollow fiber membrane filter. BACKGROUND

[0002] Hollow fiber membrane filters are used for removing unwanted particles or constituents from a liquid flow for many different fields of application. Hollow fiber membrane filters comprising polymeric or ceramic membranes, such as silica based membranes, hydrophilic cellulose acetate membranes or hydrophobic polyether sulfone membranes can be used for filtration of drinking water, for water treatment or for water re-use applications. Hollow fiber membrane devices are also used for biological or medical applications, such as substrates for bioreactor systems or as part of a dialysis device.

[0003] For many hollow fiber membrane filters it is necessary to remove air from the hollow fiber material within the hollow fiber membrane filter and to fill the hollow fiber material with liquid in order to prepare the hollow fiber material prior to first use of the hollow fiber membrane filter. Otherwise the first amount of liquid forced through the hollow fiber membrane filter will not be completely treated by the hollow fiber material and the efficiency of the hollow fiber material will be reduced during subsequent filtration processes of liquid flowing through the hollow fiber material.

[0004] For water treatment applications the hollow fiber membrane filter has to be inserted into a filter device comprising two compartments which are arranged one above the other and which are separated by the hollow fiber membrane filter. After filling the upper compartment with water the weight of the water causes the water to flow through the hollow fiber membrane filter into the lower compartment resulting in a filtration process of the water. However, the hollow fiber membrane filter inserted into such a filter device also has to be vented after removal of the hollow fiber membrane filter from the transport packaging and prior to first use of the hollow fiber membrane filter.

[0005] It is known from practice to arrange a hollow fiber membrane filter below a funnel and after adding a large amount of water into the funnel, to wait until the water has flown from the funnel through the hollow fiber membrane filter, thereby deaerating the hollow fiber material. However, a funnel is required and it often takes some time for the water to flow through the hollow fiber membrane filter. It is also possible to insert the hollow fiber membrane filter into a filter device and to fill the upper compartment with water. After all the water has flown from the upper compartment through the hollow fiber membrane filter into the lower compartment, the water is removed from the lower compartment, but not for human consumption, because the filtering efficiency of the hollow fiber membrane filter only gradually increases during the deaeration process. This step can be repeated until the deaeration of the hollow fiber membrane filter is complete. Even though this deaeration process does not require an additional funnel, it takes some time during the deaeration process to repeatedly fill the upper compartment, wait for the water to flow through the hollow fiber membrane filter, and empty the lower compartment.

[0006] Therefore, there is a need for a method for deaerating a hollow fiber membrane filter which can be easily and quickly performed. SUMMARY

[0007] The present invention relates to a method for deaerating a hollow fiber membrane filter arranged within a transport package, whereby during a bag filling step an amount of liquid is filled into a cavity formed by a flexible and liquid tight open bag at a first end, which bag is liquid tight sealed along a circumferential surface of a housing of the hollow fiber membrane filter at a first front side of the housing of the hollow fiber membrane filter and characterized in that during a deaeration step the amount of liquid in the cavity is forced through the hollow fiber membrane filter in order to exit at the second front side of the housing of the hollow fiber membrane filter. The bag thus provides a cavity in which the liquid can be filled which is required to deaerate the hollow fiber membrane filter during the deaeration step. Therefore, no additional equipment is required, such as a funnel which is usually required to perform the deaeration step according to the prior art.

[0008] A pressure can be applied on the cavity to force the liquid quickly through the hollow fiber membrane filter. Therefore, the time required for the amount of liquid to pass through the hollow fiber membrane filter can be significantly reduced by this method.

[0009] A large bag can be provided which is large enough to fill an amount of liquid which is sufficient to complete the deaeration process after a single pass of the liquid through the hollow fiber membrane filter from the closed cavity. However, it is also possible to repeat the bag filling step and the deaeration step one or several times until enough liquid is forced through the hollow fiber membrane filter to completely deaerate the hollow fiber membrane filter.

[0010] According to an advantageous aspect of the invention, during the bag filling step after filling the cavity with liquid through the first opening at the first end of the bag, the first end of the bag is closed in order to enclose the amount of liquid in the bag at the first front side of the housing of the hollow fiber membrane filter. By closing the cavity, it is very easy to apply pressure to the cavity by compressing the cavity section of the flexible bag, i.e. by reducing the size of the closed cavity, resulting in an increased pressure forcing the liquid through the hollow fiber membrane filter. The first end of the bag can be closed by manually squeezing the bag material at or near the first end. It is also possible to fold the bag one or several times near the opening at the first end in order to close the opening or to shut the opening from the cavity.

[0011] In yet another embodiment of the invention, during the bag filling step and after filling the cavity with liquid, the first opening of the bag is closed by several winding movements of the first end of the bag around a winding axis. By winding the first end of the transport package around the winding axis, the first opening at the first end can be tightly sealed without having to exert more effort and without having a greater risk of error in the process. The winding axis should be substantially parallel to the surface of the first front side of the housing of the hollow filter membrane filter. However, it is not necessary that the winding axis is parallel to this surface, as it is only necessary to provide a liquid-tight seal of the first end of the transport package. The distance between the opening at the first end of the bag and the first front side of the housing of the hollow filter membrane filter is preferably greater than the distance required to close the cavity in order to facilitate handling of the bag and to enable the first end to be subjected to several winding movements with the cavity filled with liquid. If the filled cavity extends for example 5 centimeters, the distance between the opening at the first end and the first front side of the housing of the hollow filter membrane filter can be for example 10 centimeters or more, allowing to wind at least 5 centimeters around the winding axis which is parallel to the first front side which is considered to be sufficient to provide a liquid-tight seal. However, if the distance between the opening at the first end and the filling level of the cavity is greater than 5 centimeters, for example 10 centimeters, 15 centimeters or any other distance considered to be sufficiently large, it is possible and likely to further facilitate handling.

[0012] The winding movement of the first end of the bag can be performed manually without any support element. However, in order to further facilitate the winding movement, the winding movement can be performed around a winding axis element, such as for example a rod or a stick manually arranged along said winding axis. The winding axis element can be a pen, a cooking spoon or the like which is available to the user to perform the venting of the hollow filter membrane filter. It is also possible to attach a winding axis element, such as for example a stick, to the housing of the hollow fiber membrane filter or to the transport package and to provide the winding axis element together with the hollow fiber membrane filter for use during the venting process.

[0013] According to a very advantageous aspect of the present invention, the size of the cavity formed by the closed first end portion of the bag is reduced during the venting step, thereby forcing the liquid through the hollow fiber membrane filter. By reducing the size of the cavity, pressure is applied to the liquid that has been filled into the cavity, and the liquid is forced through the hollow filter membrane filter by the pressure. The greater the pressure, the faster the venting process can be performed and completed, and the faster the hollow filter membrane filter is ready for installation of the hollow filter membrane filter into the filter device.

[0014] According to a particularly advantageous embodiment of the present invention, the size of the cavity is reduced by manually compressing the flexible bag. This can be performed, for example, by adding a further winding motion at the first end portion of the bag, thereby continuously reducing the size of the cavity by moving the wound and liquid-tight sealed first end portion of the bag towards the first front side of the housing of the hollow filter membrane filter. The side walls of the bag within the cavity section can also be pressed together. In case the diameter of the bag within the cavity section is about 10 centimeters or less, the cavity section can be gripped and compressed with one hand. It is also possible and advantageous for large diameter cavity sections that the cavity section is placed on a support surface and then pressed together with one hand, which is placed from above on the cavity section.

[0015] According to an aspect of the present invention, at least a portion of the bag protruding above the housing of the hollow fiber membrane filter housing is separated and removed after venting the hollow fiber membrane filter. It is also possible to completely remove the bag from the housing of the hollow fiber membrane filter. The liquid-tight sealing of the bag to the circumferential surface of the housing can be performed, for example, by gluing or friction welding the bag to the surface in such a way that the bag can be manually removed from the surface and thus from the housing after performing the venting step.

[0016] According to an embodiment of the application considered to be very advantageous, the transport packaging of the housing of the hollow fiber membrane filter can be adapted and used to support and perform the required venting of the hollow fiber membrane filter prior to the first use. Thus, during the transport packaging preparation step, the flexible and liquid-tight transport packaging liquid-tightly sealed along the circumferential surface of the housing of the hollow fiber membrane filter is opened at the first end and opened at the second end, thereby opening the first and second openings of the transport packaging at the opposite front sides of the housing of the hollow fiber membrane filter to the corresponding first and second openings of the hollow fiber membrane filter. The portion of the transport packaging protruding above the first front side of the housing having the first opening of the hollow fiber membrane filter forms the bag. The transport packaging can be designed and adapted to provide the bag at the first front side of the housing which allows for all aspects during the venting of the hollow fiber membrane filter as described above. However, no additional material for a separate bag is required and no additional manufacturing step for manufacturing the bag and fastening the bag to the housing prior to inserting the housing into the transport packaging is required. Thus, manufacturing costs can be reduced. Furthermore, due to the reduced material requirement, the method can be performed in an ecologically worthwhile and environmentally friendly manner.

[0017] According to a further embodiment of the application, during the transport packaging removal step, at least a portion of the transport packaging protruding above the housing of the hollow fiber membrane filter and at least a portion of the transport packaging having the second end are separated and removed from the housing. If all portions of the transport packaging protruding above the housing of the hollow fiber membrane filter prior to the removal are removed, these portions of the transport packaging will not cause an interference during the installation of the hollow fiber membrane filter into the filter device or during the subsequent use of the hollow fiber membrane filter for filtering a liquid. In order to facilitate the removal of these portions of the transport packaging, the areas of the transport packaging to be separated can be connected to the remaining areas of the transport packaging via suitable perforations. It is also possible to attach the transport packaging to the housing of the hollow fiber membrane filter such that the entire transport packaging is allowed to be easily removed from the housing after performing the venting of the hollow fiber membrane filter. The present application also relates to a hollow fiber membrane filter device having a housing comprising a hollow fiber membrane filter.

[0018] Generally, such hollow fiber membrane filters are encapsulated within a flexible transport packaging made of a plastic foil or made of an impregnated and water-proof paper material in order to avoid an unwanted soiling or contamination of the hollow fiber membrane filter after the manufacturing and prior to the use within the filter device, for example during storage at a distributor or during transportation from the manufacturer to the distributor up to the end customer.

[0019] Just prior to the installation of the hollow fiber membrane filter into the filter device, the hollow fiber membrane filter is removed from the transport packaging and has to be vented in order to ensure a proper operation of the hollow fiber membrane filter during the filtration process.

[0020] It is considered an object of the present invention to provide a hollow fiber membrane filter which facilitates the desired preparation prior to mounting the hollow fiber membrane filter into a filter device.

[0021] According to an advantageous aspect of the invention, a flexible and liquid-tight open pocket is liquid-tightly sealed along the circumferential surface of the housing of the hollow fiber membrane filter at the first front side of the housing of the hollow fiber membrane filter. Such a pocket can be easily mounted and sealed onto the housing of the hollow fiber membrane filter, for example by gluing, by friction welding or by heat shrinking. The weight of the pocket does not contribute significantly to the weight of the hollow fiber membrane filter device. However, by adding a pocket to the housing of the hollow fiber membrane filter, the evacuation of the hollow fiber membrane filter prior to its first use can be significantly facilitated and accelerated. The pocket can be made of a flexible and liquid-tight foil. The design of the pocket can be adapted to provide a cavity section which is large enough to accommodate a liquid volume which is sufficient to fully evacuate the hollow fiber membrane filter.

[0022] The shape of the pocket is adapted to be sealed in a liquid-tight manner onto the circumferential surface of the housing of the hollow fiber membrane filter. For most applications, the cross-section of the housing will be circular or elliptical. The cross-section of the pocket within the sealing section of the pocket is preferably adapted to resemble the cross-section of the housing. The pocket can be tubular. However, it is also possible to provide a pocket having a conical or a barrel shape.

[0023] According to a further advantageous aspect of the invention, the transport packaging is made of a flexible and liquid-tight transport packaging material and the transport packaging is liquid-tightly sealed along the circumferential surface of the housing of the hollow fiber membrane filter, wherein a first end portion of the transport packaging covers the first front side of the housing and wherein a second end portion of the transport packaging covers the second front side of the housing, whereby said pocket is formed by a cavity section between said first end portion of said transport packaging and said first front side of said housing of said hollow fiber membrane filter. After opening the first and second end portions of the transport packaging, a user can fill liquid into the opening of the first end portion of the transport packaging, which liquid flows through the hollow fiber membrane filter and is discharged from the transport packaging through the second opening at the other side of the housing of the hollow fiber membrane filter. Thus, the transport packaging can be used to provide the pocket and to support the evacuation process and allow the user to perform the evacuation process without the need for additional tools, such as for example a funnel for evacuating the hollow fiber material within said hollow fiber membrane filter.

[0024] According to an embodiment of the present invention, the cross section of the transport package is adapted to the cross section of the circumferential surface of the housing of the hollow fiber membrane filter along which the liquid-tight seal is provided. Thus, the transport package can be shrink-fitted or welded onto the side surface of the housing without significant deformation of the shape of the transport package at or around the liquid-tight seal. Adapting the cross section of the transport package to the corresponding cross section of the housing along the liquid-tight seal facilitates the liquid-tight fastening of the transport package to the housing. Furthermore, the dimensions of the transport package can be minimized.

[0025] According to one embodiment of the present invention, the housing of the hollow fiber membrane filter is tubular and the transport package is tubular. The tubular housing provides a circular cross section of the first and second front side of the housing. The hollow fibers can extend in a straight line from the first front side to the second front side. This design allows for a high performance filter device which makes very efficient use of the hollow fiber material arranged inside the housing. The tubular transport package can easily and cost effectively be manufactured from a membrane tube. After inserting the housing into a section of such a membrane tube, the first and second end portions of the membrane tube are closed, resulting in sealing the housing within the membrane tube between the two closed end portions. The first and second end portions of the membrane tube are located on opposite sides of the housing and both the first and second end portions are arranged at a distance from the respective first and second front side of the housing. Thus, each of the first and second end portions of the membrane tube can be pressed together to form a flat line and closed, for example by ultrasonic welding or by using an adhesive.

[0026] To facilitate the preparation of the required transport package prior to performing the venting process as described above, it is considered advantageous to arrange a first perforation at the first end portion of the transport package which allows for removing a first end portion section of the transport package at a distance from the housing of the hollow fiber membrane filter resulting in forming a cavity between the removed first end portion section of the transport package and the first front side of the housing of the hollow fiber membrane filter formed by the cavity section of the first end of the transport package. The first perforation enables the user to remove the first end portion section of the transport package and provides a first opening of the transport package through which a liquid can be filled into the cavity section of the transport package for the venting process. The first perforation can be designed to extend along the circumference of the transport package, preferably along the circumference of a tubular transport package, resulting in a large first opening inside the transport package at a distance from the first front side of the housing of the hollow fiber membrane filter.

[0027] According to embodiments of the present application, the first end portion of the transport package further comprises a closure section between the cavity section and the portion of the first end portion of the transport package which allows to close the cavity section after removal of the first end portion of the transport package. Thus, the first perforation is preferably arranged at a distance from the first front side of the housing of the hollow fiber membrane filter which is large enough to allow for a closure section between the cavity section and the first perforation and the first front side of the housing located at the first end of the transport package. Depending on the volume of the hollow fiber membrane filter which requires a venting process, the volume of the cavity section is adapted to the volume of the hollow fiber membrane filter and can for example be the same or twice the volume of the hollow fiber membrane filter. The size of the closure section is preferably at least a few centimeters in order to allow for easy handling during the closure step required to close the first opening of the transport package after filling the cavity with a liquid. For many shapes of the transport package, the length of the closure section, i.e. the distance between the first opening and the cavity section, should be at least a few centimeters, preferably more than 5 or 10 centimeters.

[0028] The size, and more specifically the length of the closure section, measuring the distance between the cavity section and the first opening of the transport package, should preferably be large enough to allow for some rolling movement of the end portion of the transport package together with the open end to close the first opening in a liquid tight manner without the need for additional tools or elements, but only some rolling movement of the user's hand. However, if deemed helpful or in order to further facilitate the venting process, and in particular the closing of the cavity by rolling the first end of the transport package, a separate rod or stick can be provided which is removably attached to the outside or inside of the transport package. Such a rod or stick can be removed by the user and arranged at the first opening of the first end of the transport package in a way that supports the rolling movement and in particular the process of rolling up or wrapping the first end of the transport package to obtain a liquid tight closure of the transport package and more specifically a liquid tight closure of the cavity which has been filled with a liquid to perform the venting process of the hollow fiber membrane filter. The length of such a rod or stick should be larger than the diameter of the first opening of the transport package after pressing the transport package together at the first opening, i.e. after flattening the transport package around and at the first opening.

[0029] To reduce the handling effort required for opening the transport package at a second end opposite the first end on the other side of the housing, optionally a second perforation is arranged at the second end of the transport package, which second perforation allows removal of a second end portion of the transport package. The removable second end can be designed as a rectangular or circular shaped slit or opening at the second end of the transport package. It is also possible to provide a second perforation which is similar to the first perforation and which extends along the circumference of the transport package at the second end of the transport package. Thus, the second opening can have a similar shape as the first opening, resulting in a second opening of large diameter, which cross section is similar or identical to the cross section of the transport package near or at the second end of the transport package. In case of a tubular transport package, the second opening can be circular with the same cross section as the cross section of the tubular transport package.

[0030] According to a further embodiment of the present application, a third perforation is arranged at the first end of the transport package next to a liquid-tight seal along the circumferential surface of the housing of the hollow fiber membrane filter. Furthermore, according to yet another embodiment of the present application, a fourth perforation is arranged at the second end of the transport package next to a liquid-tight seal along the circumferential surface of the housing of the hollow fiber membrane filter. By providing such a third perforation and a fourth perforation next to a liquid-tight seal along the circumferential surface of the housing of the hollow fiber membrane filter, it is easy to separate and remove at least a portion of the transport package protruding above the housing of the hollow fiber membrane filter from the housing. Preferably, both portions of the transport package protruding above the housing are removed before the filtration process is started. However, it is possible to remove the first end of the transport package comprising the closed section and the cavity section, for example, before inserting the hollow fiber membrane filter into the filter device in the filter seat. After inserting the hollow fiber membrane filter into the filter device by only touching the second end of the transport package, it is also possible to remove the second end of the transport package by pulling the second end from the housing of the hollow fiber membrane filter, which cuts the fourth perforation and separates the second end of the transport package from the housing.

[0031] Instead of some or all perforations, one or more of the first to fourth perforations can be replaced by an indication or separation line imprinted onto the transport package. Thus, no perforations are required within the transport package. By adding an indication or separation line imprinted onto the transport package, this will provide a clear teaching how to open and remove the transport package during and after the hollow fiber membrane filter venting.

[0032] Optionally, the transport package is made of or comprises a transport packaging material, which is a biodegradable or recyclable material. BRIEF DESCRIPTION OF DRAWINGS

[0033] The present application will become more fully understood from the detailed description and the accompanying drawings, wherein: the drawings are merely representative and are not intended to limit the scope of the claims. In fact, those of ordinary skill in the art can appreciate that various modifications and changes can be suggested by the following description and accompanying drawings, and it is intended that the present application encompass such modifications and changes. Like elements in the drawings are denoted by identical reference numerals.

[0034] Figure 1 A perspective view of a hollow fiber membrane filter with a tubular housing arranged inside a transport package is shown, wherein the transport package is made of transparent transport packaging material for the sake of clarity;

[0035] Figure 2 A perspective view of a hollow fiber membrane filter with a tubular housing arranged inside a transport package is shown, wherein the transport package is made of transparent transport packaging material for the sake of clarity; Figure 1 A cross-sectional view of the hollow fiber membrane filter of the transport package shown in Figure 1 along line II-II in

[0036] Figure 3 A perspective view of the hollow fiber membrane filter of Figure 1 and Figure 2 after filling the hollow cavity section of the transport package with a liquid;

[0037] Figure 4 A perspective view of the hollow fiber membrane filter of Figure 3 after closing the hollow cavity section of the transport package comprising a liquid;

[0038] Figure 5 A perspective view of the hollow fiber membrane filter of Figure 3 and Figure 4 during compression of the hollow cavity section of the transport package, which forces the liquid through the hollow fiber material of the hollow fiber membrane filter;

[0039] Figure 6 A perspective view of the hollow fiber membrane filter after removing the two end portions of the transport package, which protrude further above the housing of the hollow fiber membrane filter;

[0040] Figure 7 A perspective view of another embodiment of a hollow fiber membrane filter with a transport package, which can be removed differently than the embodiment shown in Figure 6 ; and

[0041] Figure 8 A perspective view of yet another embodiment of a hollow fiber membrane filter with a bag, which is sealed liquid-tight to the housing of the hollow fiber membrane filter. DETAILED DESCRIPTION

[0042] By way of example,Figure 1 and Figure 2 A perspective view and a cross-sectional view of a hollow fiber membrane filter 1 inside a flexible transport package 2 is shown. For the purpose of illustrating some aspects of the present invention, the transport package 2 is shown as made of a transparent transport packaging material. However, the transport package 2 can be made of any suitable transport packaging material, such as a flexible plastic film or an impregnated paper material, which is water-tight for at least a few minutes. Preferably, the transport packaging material is a biodegradable or recyclable material.

[0043] The hollow fiber membrane filter 1 comprises a tubular housing 3 having a first opening 4 at a first front side 5 of the housing 3 and a second opening 6 at a second front side 7 of the housing, which is opposite the first opening 4 and the first front side 5 of the housing 3. Thus, the shape of the housing 3 resembles a cylindrical shell. Inside the housing 3 there is a hollow fiber material 8 having a multitude of hollow fibers 9 extending from the first front side 5 to the second front side 7 of the housing 3 and arranged parallel to each other. The hollow fiber membrane filter 1 can be used for removing unwanted particles or components from a liquid flow, which enters the hollow fiber membrane filter 1 through the first front side 5, flows through the hollow fiber material 8, and exits through the second front side 7 of the housing 3.

[0044] The hollow fiber membrane filter 1 is arranged inside the transport package 2 made of a tube film, the cross-section of which is adapted to the cross-section of the hollow fiber membrane filter 1. By shrinking the transport package 2 onto the adhesive ring 11, which provides a liquid-tight seal along the circumferential line, the hollow fiber membrane filter 1 is fixed to the transport package 2 along the circumferential surface 10 of the housing 3. It is also possible to fasten the transport package 2 with the housing 3 of the hollow fiber membrane filter 1 together by, for example, ultrasonic welding or gluing with a suitable adhesive that provides a liquid-tight seal.

[0045] The first end portion 13 of the tubular transport package 2 has been sealed by pressing the first end portion 13 flat and then closing it by, for example, ultrasonic welding. The second end portion 14, which is opposite the first end portion 13 and on the other side of the hollow fiber membrane filter 1, has also been sealed by pressing the second end portion 14 flat and then closing it by, for example, ultrasonic welding. Thus, the transport package 2 made of a tube film provides a sealed wrapping of the hollow fiber membrane filter 1 during transport and storage of the hollow fiber membrane filter 1 until the degassing process is started and the subsequent use of the hollow fiber membrane filter 1 with a filter device.

[0046] To perform the required venting of the hollow fiber material prior to the first use of the hollow fiber membrane filter, during the transport packaging preparation step, the flexible and liquid-tight transport packaging 2 is opened at the first end 13 and at the second end 14, thereby providing a first opening 15 and a second opening 16 of the transport packaging 2, which open into the corresponding first opening 4 and second opening 6 of the hollow fiber membrane filter 1 at the opposite front sides 5, 7 of the housing 3 of the hollow fiber membrane filter 1. The manual opening of the first end 13 is supported and simplified by a first perforation 17, which extends along a circumferential line of the tubular transport packaging 2, close to the first end 13 of the transport packaging 2. In the same way, the manual opening of the second end 14 is supported and simplified by a second perforation 18, which extends along a curve close to the second end 14 of the transport packaging 2. By pulling a first end portion 19 of the transport packaging 2, the first perforation 17 is cut and the first end portion 19 with the closure of the tubular transport packaging 2 is removed from the rest of the transport packaging 2, resulting in the creation of the first opening 15 at the first end 13 of the transport packaging 2. Similarly, by pulling the second end 14 of the transport packaging 2, the second perforation 18 is cut and a second end portion 20 with the respective closure of the tubular transport packaging 2 is also removed from the rest of the container, resulting in the second opening 16 opposite the first opening 15. The portion of the transport packaging 2 between the first end 13 and the liquid-tight seal 12 forms a bag 27. After the removal of the first end portion 19 from the transport packaging 2, the interior of the bag 27 is accessible through the first opening 15 at the first end 13 of the transport packaging 2.

[0047] During a subsequent bag filling step, the transport packaging 2 is arranged with the first opening 15 facing upwards and the second opening 16 facing downwards. An amount of liquid 21 is filled through the first opening 15 at the first end 13 into a cavity 22 formed by the transport packaging 2 close to the first front side 5 of the housing 3 of the hollow fiber membrane filter 1. Figure 3 The cavity 22 filled with liquid 21 within the transport packaging 2 is shown, the liquid 21 can be for example tap water. The cavity 22 is formed by a cavity section 23 of the transport packaging 2. Due to gravity, the liquid 21 slowly soaks through the hollow fiber membrane filter 1 and some droplets leave the housing 3 of the hollow fiber membrane filter 1 at the second, downwards facing front side 7.

[0048] Between the upwards first opening 15 and the lower cavity section 23, there is a closure section 24, which can be used to close the bag 27, i.e. to close the cavity 22 after filling the cavity 22 with the liquid 21. The size of the closure section 24, i.e. the distance between the cavity section 23 and the first opening 15, is large enough to allow some manual winding movements of the first end 13 of the transport package 2, resulting in wrapping at least a part of the closure section 24 of the transport package 2 starting from the first end 13 of the transport package 2 until the cavity 22 with the liquid 21 therein is liquid-tightly sealed at the first end 13 of the transport package 2, which is shown in Figure 4 .

[0049] During the venting step shown in Figure 5 , the amount of liquid 21, i.e. in the bag 27 within the closed cavity 22, is forced through the hollow fiber membrane filter 1 by compressing the cavity 22 and reducing the volume of the cavity 22. This can be done manually by pressing the opposite sides of the cavity section 23 together, or by adding further winding movements to the wound first end 13 of the transport package 2. By reducing the volume of the cavity 22 a pressure is built up, which forces the liquid 21 through the housing 3 of the hollow fiber membrane filter 1 and out at the second front side 7 of the housing 3 of the hollow fiber membrane filter 1. The liquid 21 and the hollow fiber material therein, which has passed the housing 3, leaves the transport package 2 through the second opening 16 at the second end 14 of the transport package 2. Due to the pressure applied to the cavity 22 and the liquid 21 therein, the liquid 21 is forced through the housing 3 in a much shorter duration than the soaking process, wherein only the force of gravity pushes the liquid 21 through the housing 3, resulting in a slow soaking process, which requires much more time than the time needed to apply pressure to the cavity and force the liquid 21 through the housing 3 at a high flow rate. After most or all of the liquid 21 is forced through the housing 3, the venting step is completed. If needed, the transport package filling step and the venting step can be performed repeatedly in order to force a large amount of liquid 21 through the housing 3, whereby the large amount of liquid 21 is larger than the volume of the cavity 22.

[0050] After the complete venting process is finished, the first end portion 13 of the transport package 2 protruding above the housing 3 can be detached from the housing 3 by pulling the first end portion 13 away from the housing 3, resulting in the severing of the third perforation 25 close to the liquid-tight seal 12 along a circumferential line of the housing 3. The housing 3 of the hollow fiber membrane filter 1 can then be inserted into a filter device, not shown in the figures, first with the first front side 5 of the housing 3. During the installation of the housing 3 into the filter device, the hollow fiber membrane filter 1 can be handled by the user by only touching the second end portion 14 of the transport package 2, which remains attached to the housing 3 during the insertion of the housing 3 into the filter device. After the housing 3 of the hollow fiber membrane filter 1 is fixed into the filter device, the second end portion 14 of the transport package 2 can also be removed by pulling the second end portion 14 away from the housing 3. This will sever the fourth perforation 26 and allow the second end portion 14 to detach from the housing 3 of the hollow fiber membrane filter 1.

[0051] It is also possible to remove the second end portion 14 of the transport package 2 first and then the first end portion 13 of the transport package 2. The order of the consecutive removal of the first end portion 13 and the second end portion 14 can be adapted to the way the housing 3 is installed into the filter device.

[0052] By attaching such a transport package 2 to the housing 3 of the hollow fiber membrane filter 1 in a liquid-tight manner, the required venting process of the hollow fiber membrane filter 1 can be performed manually in a very short time without the need for additional tools or elements. The hollow fiber membrane filter 1 can then be inserted into a filter device without touching the housing 3 of the hollow fiber membrane filter, thereby reducing the risk of any unwanted contamination of the hollow fiber membrane filter 1 during the venting process and the subsequent installation into the filter device. The transport package 2 can be manufactured in a very cost-efficient way and can be easily attached to the housing 3 by well-known methods, such as e.g. ultrasonic welding, while providing a liquid-tight seal.

[0053] Figure 7 Another embodiment of the hollow fiber membrane filter 1 is shown, wherein only a part of the design of the transport package 2 differs from the embodiment shown in Figures 1 to 6 The first end portion 13 of the transport package 2 having the first end portion 19 and the cavity 22 is similar to the embodiment shown in Figures 1 to 6The second end portion 14 and in particular the second opening 16 is different from the embodiment shown in Fig. 1. Instead of the fourth perforation 26 extending around a circumferential line of the housing 3 in the vicinity of the liquid-tight seal 12, the fourth perforation 26 extends perpendicular to the circumferential line and perpendicular to the alignment of the second end portion 20 of the transport package 2. The fourth perforation 26 starts at the second end portion 20 and extends in the direction of the housing 3, wherein the liquid-tight seal 12 is located next to the first front side 5 of the housing 3. The fourth perforation 26 can end at a distance from the liquid-tight seal 12, since the fourth perforation 26 implies a forced opening of the transport package 2 and a forced separation at the second end portion 20 providing two separated portions 28, 29. This will enable a person to grab the two separated portions 28, 29 and peel off and remove the complete transport package 2 from the housing 3. To facilitate this complete removal of the transport package, the liquid-tight seal 12 can be designed in a way that it allows a residue-free removal of the adhesive ring 11 from the housing 3 after the venting step is completed.

[0054] Figure 8 Another embodiment of the hollow fiber membrane filter 1 according to the present invention is shown. Instead of the transport package 2 being fixed at the housing 3 with a liquid-tight seal 12, there is only a separate bag 27 fixed at the housing 3. The separate bag 27 can be made of a flexible plastic film or an impregnated paper material that is water-tight for at least a few minutes. The bag 27 is fixed to the housing 3 by ultrasonic welding or heat shrinking. Preferably, the bag 27 is made of a biodegradable or recyclable material. The shape of the bag 27 can be tubular with a constant cross-sectional area. The shape of the bag 27 can also be conical or abdominal to allow a cross-sectional area that is larger than the cross-sectional area of the housing 3 of the hollow fiber membrane filter 1. The bag 27 can be open-ended at the first end portion 13 opposite the liquid-tight seal 12. The bag 27 can also be closed at the first end portion 13 in order to prevent any contamination of the interior of the bag 27 before the venting step is performed.

[0055] Instead of the embodiments shown in Fig. 1 and Fig. 2, the hollow fiber membrane filter 1 and the bag 27 can be arranged inside a transport package that is not fixed to the hollow fiber membrane filter with a liquid-tight seal. The transport package can be any transport package known from the prior art, for example a paperboard package or a fabric bag. The bag 27 does not require much space inside the transport package. Figure 8 Instead of the embodiments shown in Fig. 1 and Fig. 2, the hollow fiber membrane filter 1 and the bag 27 can be arranged inside a transport package that is not fixed to the hollow fiber membrane filter with a liquid-tight seal. The transport package can be any transport package known from the prior art, for example a paperboard package or a fabric bag. The bag 27 does not require much space inside the transport package.

Claims

1. A method for deaerating a hollow fiber membrane filter (1) in a filtration device prior to first use of the filter, whereby liquid (21) is forced through the hollow fiber membrane filter (1), wherein During a bag filling step, an amount of liquid (21) is filled into a cavity (22) formed by a flexible and liquid-tight open pocket (27) which is liquid-tightly sealed along a circumferential surface of the housing (3) of the hollow fiber membrane filter (1) at a first front side (5) of the housing (3) of the hollow fiber membrane filter (1), wherein, during the bag filling step, after filling the liquid (21) into the cavity (22) through a first opening (15) at a first end portion (13) of the pocket (27), the first end portion (13) of the pocket (27) is closed in order to enclose an amount of the liquid (21) in the pocket (27) at the first front side (5) of the housing (3) of the hollow fiber membrane filter (1), wherein, during a deaeration step, by reducing the size of the cavity (22) formed by the closed first end portion (13) of the pocket (27), an amount of the liquid (21) in the cavity (22) is forced through the hollow fiber membrane filter (1) to exit at a second front side (7) of the housing (3) of the hollow fiber membrane filter (1), and wherein, after the deaeration step has been performed and completed, the hollow fiber membrane filter is installed into the filtration device.

2. The method of claim 1, wherein, During the bag filling step, after filling the liquid (21) into the cavity (22), the first opening (15) of the pocket (27) is closed by a plurality of winding movements of the first end portion (13) of the pocket (27) around a winding axis.

3. The method of claim 1 or 2, wherein, The size of the cavity (22) is reduced by manually compressing the pocket (27).

4. The method of claim 1 or 2, wherein, After deaerating the hollow fiber membrane filter (1), at least a portion of the pocket (27) protruding above the housing (3) of the hollow fiber membrane filter (1) is separated and removed.

5. The method of claim 1 or 2, wherein, During a bag preparation step, a flexible and liquid-tight closed transport package (2) which can be used as the pocket (27) and which is liquid-tightly sealed along a circumferential surface of a housing (3) of the hollow fiber membrane filter (1) is opened at a first end portion (13) and opened at a second end portion (14), thereby providing a first opening (15) and a second opening (16) of the transport package (2) with access to the respective first opening (15) and second opening (16) at opposite front sides (5, 7) of the housing (3) of the hollow fiber membrane filter (1).

6. The method of claim 5, wherein, During a transport package removal step, at least a portion of the transport package (2) having the first end portion (13) protruding above the housing (3) of the hollow fiber membrane filter (1) and at least a portion of the transport package (2) having the second end portion (14) are separated from the housing (3) and removed.

7. A hollow fibre membrane filter device for performing the method according to any one of the preceding claims, comprising a hollow fibre membrane filter (1) for mounting into a filtration device, the hollow fibre membrane filter (1) comprising a housing (3) enclosing a hollow fibre material (8), wherein, A flexible and liquid-tight open pocket (27) is liquid-tightly sealed along a circumferential surface of the housing (3) of the hollow fiber membrane filter (1) at a first front side (5) of the housing (3) of the hollow fiber membrane filter (1).

8. The hollow fiber membrane filter device according to claim 7, having a transport package (2) enclosing the housing (3) after manufacturing the hollow fiber membrane filter (1) and before using the hollow fiber membrane filter (1), wherein the transport package (2) is made of a flexible and liquid-tight transport packaging material, and wherein the transport package (2) is liquid-tightly sealed along a circumferential surface of the housing (3) of the hollow fiber membrane filter (1), wherein a first end portion (13) of the transport package (2) covers a first front side (5) of the housing (3) and a second end portion (14) of the transport package (2) covers a second front side (7) of the housing (3), whereby the pocket (27) is formed by a cavity section between the first end portion (19) of the transport package (2) and the first front side (5) of the housing (3) of the hollow fiber membrane filter (1).

9. The hollow-fiber membrane filter device of claim 8, wherein, A cross section of the transport package (2) is adapted to a cross section of the circumferential surface of the housing (3) along which the housing (3) is provided with a liquid-tight seal (12).

10. The hollow-fiber membrane filter device of claim 9, wherein, The housing (3) of the hollow fiber membrane filter (1) is tubular and wherein the transport package (2) is tubular.

11. The hollow fiber membrane filter device according to any one of claims 8 to 10, wherein, A first perforation (17) is arranged at the first end portion (13) of the transport package (2), the first perforation (17) allowing to remove a first end portion (19) of the transport package (2) at a distance from the housing (3) of the hollow fiber membrane filter (1), thereby causing a cavity (22) to be formed by a cavity section (23) of the first end portion (13) of the transport package (2) between the removed first end portion (19) of the transport package (2) and the first front side (5) of the housing (3) of the hollow fiber membrane filter (1).

12. The hollow-fiber membrane filter device of claim 11, wherein, The first end portion (13) of the transport package (2) further comprises a closing section (24) between the first end portion (19) of the transport package (2) and the cavity section (23), the closing section (24) allowing to close the cavity section (23) after removing the first end portion (19) of the transport package (2).

13. The hollow-fiber membrane filter device of any one of claims 8-10, wherein, A second perforation (18) is arranged at the second end portion (14) of the transport package (2), the second perforation (18) allowing to remove a second end portion (20) of the transport package.

14. The hollow-fiber membrane filter device of any one of claims 8-10, wherein, A third perforation (25) is arranged at the first end portion (13) of the transport package (2) in proximity to a liquid-tight seal (12) along a circumferential surface of the housing (3) of the hollow fiber membrane filter (1).

15. The hollow-fiber membrane filter device of any one of claims 8-10, wherein, A fourth perforation (26) is arranged at the second end (14) of the transport package (2) near a liquid tight seal (12) along the circumferential surface of the housing (3) of the hollow fibre membrane filter (1). A fourth perforation (26) is arranged at the second end (14) of the transport package (2) near a liquid tight seal (12) along the circumferential surface of the housing (3) of the hollow fibre membrane filter (1).

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