GB2134405A

GB2134405A - Blood filter

Info

Publication number: GB2134405A
Application number: GB08403240A
Authority: GB
Inventors: Lucas Streator Gordon
Original assignee: AMERICAN BENTLEY Inc
Current assignee: AMERICAN BENTLEY Inc
Priority date: 1983-02-08
Filing date: 1984-02-07
Publication date: 1984-08-15
Also published as: FR2540384A1; DE3402336A1; JPS6018178A; FR2540384B1; GB2134405B; GB8403240D0

Abstract

A method for the manufacture of a blood filter comprises the sealing of the ends of a cylindrically, vertically pleated blood filter material by means of a curable resin wherein the curing and shaping of the resin is aided by heat means and a means for producing centrifugal force. A potting cap 6 is placed over one end of the filter cylinder, in which a hollow central core has optionally been inserted, and the assembly inverted and placed in a recess in a metal block 9. The assembly is then spun in a centrifuge while heating the block 9. Uncured resin, in the core 3 (if present) or in the cap 6 is thus forced into the bottom of the cap 6 where it cures and seals to the end of the filter cylinder. <IMAGE>

Description

SPECIFICATION Blood filter This invention relates to the field of blood filters. A related blood filter is disclosed in United States Patent Application Serial No. 124,312 for "Blood Filter", filed on February 25, 1980 by co-inventors, Gordon Lucas and Karl Sutherland. While the blood filter assembly of Serial No. 124,312 is entirely satisfactory, because of the importance of blood filters in extracorporal blood circuits, such as those utilized during open heart surgery, there is a constant effort to improve blood filter design.

The present invention provides: A method of manufacture for a blood filter comprising: filling a cap member with a curable resin; inserting one end of said blood filter material into said filled cap member; centrifugally spinning said blood filter material inserted into said filled cap member such that said blood filter material end inserted into said cap member is outermost during said spinning; and curing said curable resin.

The invention also provides: A method of manufacture for a blood filter comprising: filling a cap member with one selected from the group comprising epoxy, urethane, silicone, hot melt or other curable resin; inserting one end of said blood filter material into said filled cap member; centrifugally spinning said blood filter material inserted into said filled cap member such that said blood filter material end inserted into said filled cap member is outermost during said spinning and curing said member of the said group comprising of epoxy, urethane, silicone, hot melt or other curable resin.

The invention also provides: A method of manufacture for a blood filter comprising: filling a hollow central core with one of the group consisting of epoxy, urethane, silicone, hot melt or other curable resin; inserting said hollow central core, vertically, into the center of a cylindrical blood filter material assembly; placing said hollow central core and cylindrical blood filter material assembly into a cap member; centrifugally spinning the cap member such that the cap member is outermost during said spinning such that the member of the group consisting of epoxy, urethane, silicone, hot melt, or other curable resin flows outward into the end cap member sealing the blood filter material end and hollow central core end.

The method of manufacture claimed in the present invention provides for the sealng of the end of a section of blood filter material to be installed in a blood filter assembly by means of the uniform application of a sealing substance, preferably urethane, to the end of the blood filter material by means of centrifugal force. In addition, the present invention provides for the heating of the urethane during the centrifuge process to aid in the curing of the urethane. This process reults in a uniform application of the urethane to the sealed end of the blood filter material and provides for a decreased curing time.

Thus it is an object of this invention to provide an improved method of manufacture for blood filters.

It is another objection of this invention to provide a quicker and more effiecient means of manufacture for a blood filter.

Methods of manufacturing blood filters in accordance with the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a longitudinal cross-section view of a complete blood filter assembly, including the blood filter material segment as manufactured by a method of this invention.

Figure 2 is a perspective view of a cylindrical segment of blood filter material sealed at one end.

Figure 3 is a cross-sectional view of the blood filter material as seated in the centrifuge for assembly.

Figure 4 is a top view of a cylindrical blood filter material segment and the corresponding hollow central core utilized in the manufacturing process.

Figure 5 is a perspective view of the blood filter material as inserted into a potting cap during the manufacturing process.

A perspective view of the completed blood filter material segment 1 is shown in Figure 2. A hollow cylinder of pleated blood filter material 2 is shown with the top end sealed. The blood filter material segment 1 is manufactured by means of a process involving the use of a centrifuge and the application of heat to the end of the blood filter material segment 1 during the centrifuging process. The centrifuging process is more fully described in Bentley United States Patent No. 4,240,907 titled Dialyzer and Method of Dialysis, also assigned to Bentley Laboratories and hereby incorporated by reference.

In the preferred embodiment, the first step in the manufacture of the blood filter material segment 1 is the insertion of a hollow central core assembly 3 into the center of a hollow blood filter material cylinder 2 such that the open end of the hollow central core assembly 3 is co-planer with the top surface of the blood filter material cylinder 2 as shown in Figure 1.

The hollow central core assembly 3 is a hollow cylindrical tube, closed at one end and open at the other end. The outside diameter of the hollow central core 3 is less than the inside diameter of the blood filter material segment 2. A circular support ring 4 is secured around the hollow central core 3 by means of a plurality of support members 5 such that the vertical centers of the hollow central core assembly 3 and support ring 4 are vertically aligned.

The hollow central core assemblt 3 is then filled with one of any of various suitable sealing substances, such as epoxy, urethane, silicone, hot melt or any other curable resin, all of which form a nonpermeable barrier upon curing. In the preferred embodiment, urethane is used as the sealing substance. A potting cap 6 is then inserted over the end of the blood filter material segment 2 and inverted as shown in Figure 5. The blood filter material segment 2 is constructed out of any suitable filter material. In the preferred embodiment the blood filter material segment 2 consists of a sheet woven noninterlocking polyester cloth covered on both sides by a course woven interlocking polypropylene support net. The combination of polyester cloth and support net is the pleated and arranged in a hollow cylindrical configuration.

The inverted assembly is then placed into a centrifuge as shown in Figure 3. In the preferred method of manufacture, the assembly fits within a contoured recess in a metal block 9 that is designed to snuggly accomodate the potting cap 6. A hollow stabilizing cylinder 7 is then inserted over the exterior of the blood filter material segment 2 in such a manner that it fits within a void 8 between the inner suface of the potting cap 6 and the blood filter material segment 2 as shown in Figure 3. the void 8 is shown in Figure 5. The stabilizing cylinder 7 prevents the blood filter material segment 2 from distending or otherwise deforming during the centrifuging process.In the preferred method of manufacture, the assembly is then spun in a centrifuge for from approximately ten (10) to about thirty (30) minutes at a gravitational force of between about 20 and about 60 g's and preferably 55.8 g's. In addition, during the centrifuging process, the block 9 is heated to approximately 150 F. The spin time during the centrifuging process and the temperature of the block 9 may vary during the manufacturing process depending upon the sealing substance used and the curing time for said substance.

The assembly is situated in the centrifuge such that the potting cap 6 containing the blood filter material segment 2 and the open end of the hollow central core assembly 3 are outermost during the spinning of the centrifuge.

During the centrifuging process, the urethane within the hollow central core member 3 is forced outward due to the centrifugal force and passes from the hollow central core 3 by means of slots 10 in the sidewall of the central core assembly 3 located at the top of the central core assembly 3. The urethane then flows outward along the top portion of the blood filter material segment 2 within the potting cap 6 and forms a solid cap 12 sealing one end of the blood filter material cylinder as shown in Figure 2 when the urethane has cured. The assembly is then removed from the centrifuge and the potting cap 6 removed. In the event the potting cap adheres to the cured urethane, the potting cap is equipped with a tear-away tab 11 to allowforthe removal ofthe potting cap.The completed blood filter material assembly 1 is then inserted into a blood filter as shown in Figure 1. The hollow central core assembly 3 remains inside the blood filter material cylinder and acts as radial support for the blood filter material by means of the circular support ring 4 which is attached to the exterior of the hollow central core 3 by means of a plurality of support member 5. The support ring 4 also acts as a stabilizing member during the centrifuging process and prevents an inward collapse of the blood filter material segment 2 while it is being centrifuged.

An alternate embodiment of the invention provides for the manufacture of the blood filter material assembly 1 without the utilization of the hollow central core assembly 3. In this embodiment, the potting cap 6 is filled with a predetermined amount of urethane, the blood filter material segment 2 is then inserted into the potting cap 6 and this assembly is then inserted into the centrifuge block 9. The stabilizing cylinder 7 is then inserted over the blood filter material segment 2 and this combined assembly is spun in the centrifuge as in the preferred embodiment. As in the preferred embodiment the block 9 is heated to approximately 1 500F.

Having thus described the invention, numerous equivalents and alterations which do not depart from the invention will be obvious to those of ordinary skill in the art and is not intended to be limited to the embodiments descibed above, but is to be of the full scope of the appended claims.

Claims

1. A method of manufacture for a blood filter comprising: filling a cap member with a curable resin; inserting one end of blood filter material into said filled cap member; centrifugally spinning said blood filter material inserted into said filled cap member such that said blood filter material end inserted into said cap member is outermost during said spinning; and curing said curable resin

2. A method of manufacture claimed in claim 1 wherein said blood filter material is further defined as being longitudinally pleated and generally cylindrically in cross-section and being formed of woven non-interlocking polyester cloth and coarse woven interlocking polypropylene support net.

3. A method of manufacture for a blood filter comprising: filling a cap member with one selected from the group comprising epoxy, urethane, silicone, hot melt or other curable resin; inserting one end of said blood filter material into said filled cap member; centrifugally spinning said blood filter material inserted into said filled cap member such that said blood filter material end inserted into said cap member is outermost during said spinning and curing said member of the group comprising of epoxy, urethane, silicone, hot melt or other curable resin.

4. A method of manufacture claimed in claim 3 further including removing said cap without interrupting the bond between the member of the group consisting of epoxy, urethane, silicone, hot melt or other curable resin and said blood filter material.

5. A method of manufacture claimed in claim 3 or 4 wherein said blood filter material is further defined as being vertically pleated and generally cylindrically in cross-section and being formed of woven non-interlocking polyester cloth and coarse woven interlocking polypropylene support net.

6. A method of manufacture for a blood filter comprising: filling a hollow central core with one of the group consisting of epoxy, urethane, silicone, hot melt or other curable resin; inserting said hollow central core, vertically, into the center of a cylindrical blood filter material assembly; placing said hollow central core and cylindrical blood filter material assembly into a cap member; centrifugally spinning the cap member such that the cap member is outermost during said spinning such that the member of the group consisting of epoxy, urethane, silicone, hot melt, or other curable resin flows outward into the end cap member sealing the blood filter material end and hollow central core end.

7. A method of manufacture claimed in claim 6 wherein said blood filter material is further defined as being vertically pleated and generally cylindrically in cross-section and being formed of woven noninterlocking polyester cloth and coarse woven interlocking polypropylene support net.

8. A method of manufacture for a blood filter, the method being substantially as herein described with reference to, and as illustrated by the accompanying drawings.

9. A method as claimed in claim 8 but modified substantially as herein described with reference to the "alternate embodiment ofthe invention".

10. A blood filter manfactured by a method as claimed in any preceding claim.