Title of Invention

AN UPGRADED SOFT FILTER WITH THREE SHEET SYSTEM AND DOUBLE SPACERS

Abstract

An upgraded soft flexible filter with three sheet system and double spacers for removing leukocytes from blood its components comprises of three sheets which are RF sealed in the periphery of the sheets. This leuko filtration device comprises a filtration media (Fig 7) which is sandwiched in between the inlet chamber sheet (Fig 1) and the out let chamber sheet (fig. 3). The blanked middle sheet (fig 2) is used for the RF sealing of the inlet chamber sheet with the outlet chamber sheet. The filter media (fig 7) divides the filter in to two compartments, inlet chamber ( Fig 12a) and the outlet chamber ( Fig 12b), Two spacers (6a /6b) are provided in the chambers, where the first spacer is provided in between the inlet chamber sheet (fig 1) and filter media (fig 7) and the second spacer is provided in between the filter media (fig 7) and the out let chamber.

Full Text

Field of Invention: The present invention relates to an upgraded soft flexible filter with three sheet system and double spacers for removing Leukocytes from whole blood or from blood components. This application is a continuation-in-part of Indian Patent Application Serial No. IP 292/ MUM/1997, Patent No. 186655, filed on 08.05.1997, entitled " An improved composition for the manufacture of soft flexible subzero stable PVC sheet for making collapsible container" and European Patent No. 0927552B1 "A flexible collapsible blood bag". Back Ground Before storing blood components for later transfusion, it is believed to be desirable for patients who require frequent blood transfusion to remove the leukocytes from donor blood prior to transfusion. Removal of the leukocytes may be accomplished in a number of ways. Filtration is conventionally used to accomplish the leukocyte reduction. When the filter has a rigid enclosure, during the steam sterilization process, it may cause damage to flexible bags and tubes. In some cases this damage may cause piercing of the bag and /or tube resulting in to leakage which makes the system unusable for blood collection/ separation of the blood in to its components. So the flexible inline filter system was introduced. Prior Art US Patent No 7048709: This patent discloses a flexible bag (1) intended to receive a biological fluid with a view to its centrifugation. The bag includes an external enclosure (2) formed by two sheets of flexible plastic (3, 3') connected at their periphery (4) so as to define an internal volume (5) for the fluid. The external enclosure (2) is provided with at least one inlet (6) and/or outlet (7) orifice for the fluid. The bag (1) also includes means (8) for the temporary association of at least one component with the bag (1). The means (8) is disposed on the external enolosure (2), in which the temporary association means are assembled on the bag (1) on a part of the periphery (4) of the enclosure (2) and are arranged to allow the insertion of the component between the means (8) and the enclosure (2) so as to provide temporary association during the centrifugation of the bag (1). US Patent No. 6601710: A fluid filter assembly for filtering fluids such as blood is described. The assembly includes first and second filter housing elements formed by an injection molding process. Each element is flexible and includes a peripheral flange formed thereabout and a fluid communicating port formed therein. Filter media, such as a filter membrane, is sealed between the mating flanges of two elements. The fluid filter assembly is capable of collapsing and expanding during the filtration process depending upon the composition of the fluid passed there through. A method for making the filter assembly and systems for using the filter assembly are also disclosed. FR2677883: Filter pouch intended to permit sterile filtration of blood for separating its components. The filter pouch includes an outer enclosure made up of an assembly of two sheets (9, 10) made of plastic and assembled at their periphery (25). According to the invention a filter medium (11) is held in a leak proof flexible frame (12) which defines within the casing two compartments for the pouch entry (13) or exit (14) respectively. The flexible frame (12) is made up of two perforated sheets (17 and 18) of plastic between which the filter medium (11) is placed. These sheets (17 and 18) are secured to each other at a weld bead (19) at the periphery of the filter medium (11) and also at the periphery of the enclosure of the pouch (5). The invention is of interest to the manufacturers of medical equipment. US Patent No.: 6367634: This invention relates to blood filter device which consist a first and second flexible sheets, each sheet comprising a meltable material. Wherein the "meltable material of the filter serves to remove the leukocytes from blood by depth filtration. And a filter medium contains a pre filter layer, main filter layer and post filter layer each comprises a meltable material to remove aggregations present in the blood. A peripheral seal is formed by radio frequency heating and pressure in a single step to join the first and second flexible sheets directly to the filter medium and encapsulate the filter medium between the first and second flexible sheets, the first flexible sheet is overlying the pre filter layer and the second flexible sheet is overlaying the post filter layer and the main filter is sandwiched between the pre and post filter layer,. In the filter housing, the first and second sheets are made using medical grade plastic materials such as PVC- DEHP. The filter housing is formed by using radio frequency heat sealing technology. An inlet port is located in the first flexible sheet spaced from the peripheral seal for conveying blood to the filter medium and an outlet port is located in the second flexible sheet spaced from the peripheral seal for conveying blood from the filter medium. A meltable material of the post filter layer providing a fluid for passage of blood through the out let port. US Patent No: 5100564: A system for collecting and processing donated blood comprises a first porous medium interposed between a blood collection bag and a satellite bag and a second porous medium interposed between the blood collection bag and another satellite bag. The porous media are leucocyte depletion media. The system can be used to centrifuge whole blood into one or more components, and a means for protecting the system during centrifugation including a bracket carried by the centrifuge bucket for receiving the porous media. US Patent No. 6488860: This invention relates to a device for the separation of blood into blood components. The device has a collecting container for the receiving blood through a connecting line. A filter for removing leukocytes which is divided in to two chambers and it is operable in two directions. A first collecting line connecting the collecting container to the first chamber of the filter and the second collecting line connecting the second chamber of the filter to a primary container via a branch line containing leukocyte filter. A by pass line is creating a fluid connection between the collecting container and the primary container where in the by pass line circumvent the filter and allows a liquid to flow between the collecting container and the primary container means for opening and closing the first collecting line, and additive container connected to the primary container where in additive container contain a solution for storing a blood component. The whole blood located in the primary container is then separated by centrifugation in to an erythrocytes layer and a mixed layer f blood plasma and thrombocytes is then conveyed from the primary container in to the first satellite container. Subsequently the erythrocytes in the primary container are resuspended in the additive agent, and then conveyed from the primary container through the leukocyte filter in to the collecting chamber. US Patent No 6274055: This invention relates to an in line liquid filtration device usable for the filtration of the blood, blood products or to remove chemical agents. A housing having an inlet and out let port and at least one filter element capable of removing leukocytes disposed within the housing between the inlet port and outlet port so as to filter the liquid flows in to the filtration device via the inlet port. The filtration device includes a first chamber and second chamber. The device allows gases to vent the filtration device through the outlet port. The filtration device allows air there in to be purged down stream in to either an air collecting bag or in to the blood receiving bag without manipulation of the height of the filtration device or the blood receiving bag. Summary of the invention The drawbacks of the prior arts may be alleviated by using a filtration device constructed in accordance with the principles of the present invention. The soft flexible filtration device is capable of filtering blood to remove leukocytes. The filtration device includes a first chamber capable of collecting unfiltered blood, means for filtering blood in between the first chamber and the second chamber and second chamber- means for collecting filtered blood. The filtration medium is to be located between the first chamber and second chamber forming a barrier dividing the interior of the housing in to first chamber and second chamber. The first chamber( inlet chamber) is connected to the inlet port and the second chamber ( Outlet chamber) is connected to the out let port. Two spacers are provided within the housing . Trie first spacer is in the inlet chamber between its sheet and the filter media and the second spacer is in the outlet chamber between the filter media and its corresponding sheet. The first spacer is for the unfiltered blood and the second spacer is for the filtered blood. The spacers provide enough flow space to blood or its components without any constriction. In an embodiment of the present invention, there is a three sheet system with RF seal welding. The sheets to be used should be RF sealable and may be made out of medical grade soft PVC or any other suitable material. The middle sheet enables the sealing of the outlet port on to the periphery of the out let chamber, there by providing a higher recovery of leukoreduced blood. In another embodiment of the present invention, one spacer is provided in the inlet chamber between its sheet and the filter media and the second spacer is provided in the out let chamber between the filter media and its corresponding sheet. This provides both inlet and the out let chambers clear space for the flow of blood or its components as a result of which a higher flow rate is achieved from the same area of the membrane filter set. It enhances the leukoreduction efficiency per unit area of the filter membrane. In yet another embodiment of the present invention, the spacers minimize the clogging or chocking of the filter membranes and give high yields/ recovery of filtered leukoreduced blood or its components and reduces time of filtration. Yet another embodiment of the invention is that the design of the spacers are such that there is no constriction to the blood flow as a result of which the combination of the filter membranes non woven or otherwise can be used for effective leukocyte reduction. In yet another embodiment of the present invention, spacers provide higher flow rates of blood / its components during the filtration there by completing the process in lesser time. Brief description of the drawings The present filtration device constructed in accordance with the principles of the present invention is shown in figure 12 and its components and manufacturing process is depicted in figures from 1 to 12. Figure 1 shows the inlet chamber sheet. Figure 2 shows the middle sheet. The middle sheet will be blanked from the middle portion leaving only the peripheral area for the RF sealing. Figure 3 represents the out let chamber sheet. Figure 4 represents the inlet port. Figure 4a represents the right angled tube part of the inlet port. Figure 4b represents the small sheet of the inlet port. Figure 5 represents the outlet port. Figure 6 represents the spacers. Figure 6a represents the bead form of the spacers which is connected together with two connected rings provided at the ends . Figure 6b represents the mesh form of the spacers. Figure 7 represents the filter media or filter membrane set. Figure 8 represents the inlet chamber sheet with hole punched in it at the suitable location. Figure 9 represents the inlet port RF welded to the inlet chamber sheet. It shows the inlet chamber sheet (fig 7) and the inlet port (fig 4), both of which have been RF welded together using suitable RF die and RF sealing machine. Figures 10 is the cross sectional view of the assembling of the inlet chamber sheet with inlet port welded on to it ( Fig 9), blanked middle sheet ( Fig 2) between which filter media has been sandwiched and RF welded together keeping one spacer (fig 6) between the inlet chamber sheet (fig 8)and filter media (fig 7), forming the inlet chamber (12a). Figure His the cross sectional view of the assembly from fig 10 in which the middle sheet and the inlet chamber sheet have been RF welded together outside the filter media. Figure 12 shows the cross sectional view of the complete filter, with the outlet chamber sheet and the middle sheet RF welded together and with the outlet port RF sealed on the periphery and the second spacer provided between the filter media and the outlet chamber sheet. Figure 12a represents the inlet chamber. Figure 12b represents the outlet chamber. Description of the invention The flexible filter with three sheet system will broadly comprise of the three sheets as shown in cross sectional view, figure 12, spacers (6a/6b) , Inlet chamber (12a), Out let chamber(12b) and filter media (Fig 7), duly made by RF sealing of the three RF sealable soft PVC sheets and the filter media and provided with an inlet port ( fig 4) in the inlet chamber sheet and an out let port (Fig 5) on the periphery of the outlet chamber between the middle sheet and the out let chamber sheet. Inlet chamber: In the inlet chamber (fig 12a),on one side is the soft PVC sheet ( Fig.8) and on the other side is filter media (Fig.7). The soft PVC sheet is proyided with an inlet port (fig.4), made out of soft PVC and RF sealed on to the soft PVC sheet (fig 8) of this inlet chamber. The soft PVC sheet is RF welded to the filter media. Inlet chamber is provided with spacer (6a/ 6b) in between the soft PVC sheet (fig 8) and the filter media (fig. 7). The spacer will provide space for collection of unfiltered blood or its components in this chamber and is designed in such a manner so as not to restrict the flow of the blood or its components. Filter media: The filter media ( Fig. 7) consists of meltable filter membranes that are hot sealable under pressure using RF system. The filter media can be non woven plastic membrane or other membrane capable of removing leukocytes from blood or its components. The filter media membranes may consist of pre filter membranes having higher pore size followed by other membrane for filtration of one/ set of these with lesser pore sizes. The filtration media consists of number of above referred membranes that are cut in the shape and size of the filter required. The filter media is sandwiched and RF sealed in between the soft PVC sheet (fig 8) of inlet chamber (fig 12a) and the middle soft PVC blanked sheet (fig 2). Out let chamber: The filter shall have one outlet chamber ( fig 12b). The out let chamber is for collection of filtered blood / its components. The outlet chamber (fig 12b) is formed by RF sealing of the blanked middle soft PVC sheet (fig 2) to another outer soft PVC sheet (fig 3). The out let chamber (fig 12 b) is provided with an outlet port (Fig. 5) which is RF sealed between the bottom periphery of the blanked middle sheet (fig 2) and the outer soft PVC sheet (fig 3) of the outlet chamber (fig 12b). This outlet port (fig 5) is for outflow of filtered blood or its components from the outlet chamber(fig 12b). The outlet chamber( 12b) is provided with a spacer ( fig 6a/6b) between the filter media (fig 7) and the outer soft PVC sheet (fig 3) to provide space for filtered blood / its component's collection and is designed in such a manner so as .not to restrict the flow of blood / its components. Inlet port: The inlet port (fig 4) is made by injection moulding of medical grade soft PVC. It will have a right angled tube part ( Fig. 4a), one end of which is having internal diameter suitable for fixing the tubing of the blood bag system for inline, or tubing of bed side filtration. The other end of this tubing which is at right angle to this, will have a small sheet (fig 4b) which is an integral part of it. The bore of this tubing will be opening in this sheet (Fig 4b). This may be made by injection moulding. The sheet part (Fig 4b) of the inlet port (fig 4) is RF welded to the inlet chamber soft PVC sheet ( fig 8). Outlet port: An out let port (fig 5) is made by injection moulding of medical grade soft PVC. The internal diameter of the outlet port ( fig. 5) will be suitable for fixing the tubing of the blood bag system for inline or the tubing of the bed side filtration system. The outlet port (fig 5) will be RF welded on the periphery at the lowest/ bottom most level of the filter to enable free outflow of the filtered blood/ its components. Three sheet system: In the present invention, a three number medical grade soft PVC sheet system is introduced to make the filter device. Three numbers medical grade soft PVC sheets will comprise of one inlet chamber sheet (Fig 1), one blanked middle sheet (Fig 2) and one out let chamber sheet (fig 3). The blanked middle soft PVC sheet (fig 2) enables on one side the independent RF sealing of the inlet chamber soft PVC sheet (fig 8) sandwiching the filter media (fig 7) and the blanked middle soft PVC sheet (fig 2) and on the other side, the independent RF sealing of the blanked middle soft PVC sheet (fig 2) and outlet chamber soft PVC sheet (fig 3). This independent RF sealing minimizes the leakage from the filter. It also enables sealing of inlet chamber on to the periphery of the outlet chamber with the filter media sandwiched in between, there by exposing maximum filter area for higher recovery of leukoreduced blood or its components and reducing the time of filtration. The provision of the middle sheet enables the outlet port to be sealed on the periphery enabling in to easy/ user-friendly maximum removal of filtered blood/ its components from the outlet chamber , resulting in to higher yields in lesser time and giving higher outputs per unit area of the filter media. Spacers: The two number spacers introduced in this invention, may be made in the form of mesh (6b) or beads chain (6a) or any other shape. One spacer (fig 6a/6b) is provided in the inlet chamber (fig 12a) between the filter media (fig 7) and the inlet chamber sheet (fig 8) and the second spacer (fig 6a/6b) is provided in the out let chamber (fig 12b) between the filter media (fig 7) and the out let chamber sheet (fig 3). The spacers may be soft/ rigid, flexible or non flexible or semi flexible. The material for the construction of the spacers can be metals or their alloys for example stainless steel, titanium etc. The stainless steel grade can be SS 316-L, SS-316 or SS 304. For plastic, soft flexible plastic for example medical grade soft PVC or rigid plastic Polypropylene or Polycarbonate may be used. The material of the construction will be capable of bearing, without any deformation, the autoclaving/ sterilization conditions. The spacers may be soft or rigid in metal or plastic and in mesh or bead or any other form. In the case of bead chain spacer (6a), the two ends may be connected together with two connecting rings provided at the ends (Fig 6a). This may be injection moulded using soft PVC or any other suitable material. The spacer one (Fig 6) in between the filter media (fig 7) and the inlet chamber sheet (fig 8) provide enough flow space without any constriction and expose entire filter area of filter membrane set for filtration to enhance the leukocyte reduction efficiency per unit area of the filtration membrane. The spacer two in between the filtration media (fig 7) and the out let chamber sheet (fig 3) provide enough space for the entry of filtered blood or its components in to the outlet chamber and to get collected and flow out of the outlet port (fig 5) provided at the periphery of the outlet chamber (fig 12b) and give high yields / recovery of filtered leukoreduced blood or its components. The outlet port provided at the periphery results in to easy flow out of the filtered blood or its components there by making it more convenient and user friendly. The spacers also reduce the time of filtration and minimize the clogging or chocking of the filter membranes. With the space in both the inlet chamber and the out let chamber provided by the spacers, the flow of the blood is more uniform over the entire area of the filter media and the leukocyte reduction efficiency per unit area of the filter membrane is higher. In addition, the design of the spacer is such that there is no constriction to the flow of blood or its components as a result of which a combination of the filter membranes non woven or other wise can be used for effective leukocyte reduction. The spacer also provides higher flow rates of blood / its components during the filtration there by completing the process in lesser time. I claim 1. A soft flexible filter having a three sheet system for leukocyte reduction by filtration of blood or its components, comprising three sheets (12), spacers (6a, 6b), inlet chamber (12a), outlet chamber (12b) and a filter media (7) duly made by radio frequency sealing of the three RF sealable soft PVC sheets and; the filter media (7) provided with an inlet port (4) in the inlet chamber sheet and an outlet port (5) on the periphery of the outlet chamber between the middle sheet and the outlet chamber sheet; the said filter device being used for inline leuko reduction when fitted with the blood bag system in close circuit and also for bed side filtration for reduction of leukocytes from blood or its components as herein described. 2. A soft flexible filter as claimed in claim 1 wherein three sheet system enables the Radio Frequency sealing on the periphery of the sheets providing higher recovery of the leucko reduced blood/ its components. 3. A soft flexible filter as claimed in claim 1 wherein the middle sheet enables the Radio Frequency sealing of the inlet chamber sheet, filter media, middle sheet on one side and the middle sheet and the out let chamber sheet on the other side. 4. A soft flexible filter as claimed in claim 1 wherein the middle sheet enables the sealing of the outlet port on to the periphery of the outlet chamber there by providing a higher and easy recovery of leukoreduced blood/ its components. 5. A soft flexible filter as claimed in claim 1 wherein the middle sheet enables the sealing of the inlet chamber on to the out let chamber with the filter media in between these two chambers there by exposing maximum filter area for the higher recovery of lukoreduced blood or its components. 6. A soft flexible filter as claimed in claims 1 and 5 wherein it reduces the time of filtration. 7. A soft flexible filter as claimed in claim 1 wherein two spacers are provided in the soft flexible filter with three sheet system. 8. A soft flexible filter as claimed in claim 1 and 7 wherein the first spacer is provided in the inlet chamber between the filter media and inlet chamber sheet. 9. A soft flexible filter as claimed in claim 1 and 7 wherein the second spacer is provided in the outlet chamber between the filter media and the out let chamber sheet. 10. A soft flexible filter as claimed in claim 1 and 7 wherein the spacers can be metals or their alloys or plastic. 11. A soft flexible filter as claimed in claim 1 and 7 wherein the spacers are in the form of mesh or bead chain spacers where the bead spacer are connected together with two connecting rings provided at the ends. 12. A soft flexible filter as claimed in claims 1 and 7 wherein the spacers in between the filter media and the inlet chamber provide enough flow space for blood or its components without any constriction and expose entire filter area of the filter membrane set for the filtration to enhance the leukocyte reduction efficiency per unit area of the filtration membrane. 13. A soft flexible filter as claimed in claim 1 and 7 wherein the spacers reduce the time of the filtration. 14. A soft flexible filter as claimed in claim 1 and 7 wherein the spacers minimize the clogging or chocking of the filter membranes. 15. The spacers as claimed in claims 7, 8 and 9 wherein the first spacer provide a uniform flow of the blood from inlet chamber to the outlet chamber and the second spacer provides space for collection and drain out of the filtered blood/ its components through the outlet port provided at the periphery which in turn gives higher leukocyte reduction efficiency per unit area of the filter membrane. 16. A soft flexible filter as claimed in claim 1 and 7 wherein the spacers provide both the inlet and outlet chambers clear space for the flow of blood or its components as a result of which a higher flow rate is achieved from the same area of the membrane filter set. 17. A soft flexible filter as claimed in claim 1 and 7 wherein the spacers in between the filtration media and out let chamber sheet provide enough space for the filtered blood or its components to get collected and flow out of the out let port provided at the periphery of the out let chamber and give high yields/ recovery of the filtered leukoreduced blood to its components. 18. A soft flexible filter as claimed in claim 1 and 7 wherein the spacers have been provided on both the sides of filter media, in the inlet chamber and in the outlet chamber. 19. A soft flexible filter as claimed in claim 1 wherein the outlet port is provided at the bottom periphery, because of usage of three sheet system, which results not only into higher yields but also makes the flexible filter device user-friendly as the filtered blood/ its components will flow out easily by itself and do not require any tilting / handling of the filter device. 20. A soft flexible filter as claimed in claim 1 wherein the soft flexile filter is used for the inline leuko reduction when fitted on the blood bag system in close circuit and also for the bed side filtration for the reduction of leukocytes in blood or its components. 21. A process of preparation of soft flexible filter device for leuko reduction of blood or its components as claimed in claims 1-20 comprises the following steps; (a) punching the inlet chamber sheet and this punched area of the sheet is aligned to the sheet opening of the inlet port while placing in the RF die, while RF sealing, so as to allow the entry of the blood/ components in to the inlet chamber; (b) the inlet port sheet is RF sealed to the inlet chamber sheet, using suitable RF die and RF sealing machine; (c) placing the inlet chamber sheet duly sealed with inlet port on another RF die; (d) placing the spacer on the inlet chamber sheet; (e) placing the filter media set above the spacer in suitable location in RF die; (f) placing the blanked middle sheet on the filter media set and sandwiching the filter media between the two sheets by RF sealing; (g) RF welding the inlet chamber sheet and blanked middle sheet outside the filter media on the periphery using another RF die; (h) placing the above assembly on another RF die, keeping the middle sheet at the top and then placing the second spacer on the filter media; (i) loading the outlet port on the mandral of the die; (j) placing the outlet chamber sheet on the top and RF sealing to the blanked middle sheet periphery with the outlet port in it giving the filter device; 22. A soft flexible filter as claimed in claim 1 wherein the filter device is flexible.

Documents:

1978-del-2008-abstract.pdf

1978-DEL-2008-Claims-(26-02-2009).pdf

1978-del-2008-claims.pdf

1978-DEL-2008-Correspondence-Others-(26-02-2009).pdf

1978-del-2008-correspondence-others.pdf

1978-del-2008-description (complete).pdf

1978-del-2008-drawings.pdf

1978-del-2008-form-1.pdf

1978-del-2008-form-18.pdf

1978-del-2008-form-2.pdf

1978-del-2008-form-26.pdf

1978-del-2008-form-3.pdf

1978-del-2008-form-5.pdf

1978-del-2008-form-9.pdf

1978-DELNP-2008-Claims-(26-03-2009).pdf