Fluid processing apparatus

Abstract: The fluid processing apparatus of the present invention comprises a housing (2) having a first fluid inlet (3) and a first fluid outlet (4); a fluid processing tubular means (6) received in the housing; partitions (8, 9) securing the opposed ends of the fluid processing tubular means (6) to the housing (2) in a fluid tight seal to partition the housing interior into a first fluid chamber in fluid communication with the first fluid inlet (3) and the first fluid outlet (4) and a second fluid chamber defined in the fluid processing tubular means; a second fluid inlet (10) and a second fluid outlet in fluid communication with the second fluid chamber; and projections (5) formed on an inner surface of one end portion of the housing (2) so as to project toward the nearer end opening of the housing, said partition (9) of the one end portion side of said housing being secured to the one end portion of the housing so that the projections (5) are positioned within the partition (9). Therefore, if a large annular portion where the fluid processing tubular means (6) is not present is formed in the end portion of the housing, because the projections (5) are positioned in the annular portion of the partition (9), shrinkage of the potting composition forming the partition (9) is suppressed and any separation between the partition and the inner surface of the housing (2) due to the shrinkage of the potting composition is prevented. Further, it is also prevented to form a weak bond portion between the partition (9) and the inner surface of the housing (2).

Description: This invention relates to a fluid processing apparatus. More particularly, it relates to a fluid processing apparatus for processing blood, for example, to a heat exchanger for regulating the temperature of blood, an artificial lung for gas exchang in blood, a plasma separator or the like. There is hitherto known a heat exchanger in which is provided heat-exchange tubular means in the form of, for example, a plurality of heat-exchange fine tubes or a coiled tube. Also in an artificial organ such as an artificial lung, material-exchange fine tubes are provided. They are gas-exchange hollow fibers in an artificial lung or dialysis hollow fibers in an artificial kidney. The above heat excharger or artificial organ is used in the manner that blood is passed through the heat or material-exchange tubular means while heat or material-exchange medium is passed between the tubular means and the housing. EP-A-0297410 discloses an artificial lung comprising a housing to the opposed ends of which a bundle of fibres is connected in a fluid tight seal to form two chambers with respective inlets and outlets. In those apparatus, the heat or material-exchange tubular means is secured to the housing in a fluid tight seal by applying a potting composition, for example, a polyurethane base potting composition to form a partition. However, there is the possibility that the potting composition forming the partition shrinks with time. The potting composition thus peels off the inner surface of the housing due to the shrinkage not to maintain the fluid tight seal though it has established upon manufacturing. Particularly, the shrinkage of the potting composition tends to occur at the periphery of the partition where the heat or material-exchange tubular means is not present. The reason is that the shrinkage of the potting composition is suppressed by the tubular means in the area where the heat or material-exchange tubular means is present while the suppression of the shrinkage is not effected in the area where the heat or material-exchange tubular means is not present. For this reason, for example, in the case of a heat exchanger in which the end of the housing is spreaded for connecting it to another fluid processing apparatus and which has a large annular area where the heat exchange tubular means is not present, there is the large possibility that the partition peels off the inner surface of the housing due to a shrinkage of the potting composition. Although the potting composition is not separated from the inner surface of the housing in a priming operation which is carried out prior to use of a fluid processing apparatus of this kind, there is the possibility that a weak bond portion is formed due to a shrinkage of the potting composition. If an impact is accidentally applied to such an apparatus when blood is passed therethrough for, for example, heat exchange, there is the risk that the partition peels off the housing. The separation between the partition and the housing is very dangerous because heat-exchange fluid such as hot or cool water can mix with blood through the separated gap or crevice. Accordingly, it is an object of the present invention to provide a fluid processing apparatus in which a separation between the partition and the inner surface of the housing due to a shrinkage of the potting composition or the formation of a weak bond portion between the partition and the inner surface of the housing is prevented even in the case of a fluid processing apparatus having a large annular area there the fluid processing tubular means is not present. The above object is attained by a fluid processing apparatus comprising a housing having a first fluid inlet and a first fluid outlet; a fluid processing tubular means received in said housing; partitions made of a potting composition securing the opposed ends of said fluid processing tubular means to opposed end portions of said housing in a fluid tight seal to partition the housing interior into a first fluid chamber in fluid communication with said first fluid inlet and said first fluid outlet and a second fluid chamber defined in said fluid processing tubular means; a second fluid inlet and a second fluid outlet in fluid communication with said second fluid chamber; characterized in that a plurality of projections are formed on an inner surface of one end portion of said housing so as to project toward said one end portion of said housing, said plurality of projections being dispersed in an annular area so that there is formed an area where said projections are not present, said partition of the one end portion side of said housing being secured to said one end portion of said housing so that the entirety of said projections are positioned within said partition. Fig.1 is partially cross-sectional side view of an embodiment in which a fluid processing apparatus of the present invention is applied to an artificial lung equipped with a heat exchanger; Fig.2 is a cross section taken along line I-I of Fig.1; Fig.3 is a partially cross-sectional side view of another embodiment in which a fluid processing apparatus of the present invention is applied to an artificial lung equipped with a heat exchanger; Fig.4 is a cross section taken along line II-II of Fig.3; Fig.5 is a partially cross-sectional side view of another embodiment in which a fluid processing apparatus of the present invention is applied to an artificial lung equipped with a heat exchanger; and Fig.6 is a cross section taken along line III-III of Fig.5. A fluid processing apparatus of the present invention will be described with reference to embodiments shown in drawings. A fluid processing apparatus 1 of the present invention comprises a housing 2 having a first fluid inlet 3 and a first fluid outlet 4; a fluid processing tubular means 6 received in the housing 2; partitions 8 and 9 securing the opposed ends of the fluid processing tubular means 6 to the housing 2 in a fluid tight seal to partition the housing interior into a first fluid chamber in fluid communication with the first fluid inlet 3 and the first fluid outlet 4 and a second fluid chamber defined in the fluid processing tubular means 6; a second fluid inlet 10 and a second fluid outlet in fluid communication with the second fluid chamber; and projections 5 formed on an inner surface of one end portion of the housing 2 so as to project toward the nearer end opening of the housing 2, said partition 9 of the one end portion side of the housing 2 being secured to the one end portion of the housing 2 so that the projections 5 are positioned within the partition 9. An embodiment in which the fluid processing apparatus of the present invention is applied to an artificial lung equipped with a heat exchanger will be described with reference to Figs.1 and 2. Fig.1 is a partially cross-sectional side view of an embodiment in which the fluid processing apparatus is applied to an artificial lung equipped with a heat exchanger and Fig.2 is a cross section taken along line I-I of Fig.1. A heat exchanger 1 to which the fluid processing apparatus of the present invention is applied is attached coaxially with an artificial lung 20. The heat exchanger 1 includes a tubular housing 2 and a heat-exchange tubular means 6 as fluid processing tubular means received in the tubular housing 2. The heat-exchange tubular means 6 comprises a large number of heat-exchange fine tubes. Each heat-exchange fine tube is made of metal having a high heat conductivity such as stainless steel, aluminum and copper. It has an inner diameter of 0.5 to 10 mm, preferably 2 to 5 mm. About 10 to about 2,000, preferably about 50 to about 1,000 heat-exchange fine tubes are received in the housing 2. The heat-exchange fine tubes are illustrated as straight tubes in Fig.1 though they may be spiral tubes. The opposed ends of the heat-exchange tubular means 6 are secured to the housing 2 through partitions 8 and 9 in a fluid tight manner. The partitions 8 and 9 are made of a high-molecular potting composition such as polyurethane and silicone rubber. The heat-exchange tubular means 6 and the partitions 8 and 9 partition the interior of the housing 2 into the first fluid chamber which is a heat-exchange fluid chamber and the second fluid chamber which is a blood chamber. The tubular housing 2 is provided with a heat-exchange fluid inlet 3 and a heat-exchange fluid outlet 4. The housing 2 may be cylindrical or polygonal in configuration. A cylindrical housing is preferred. The housing 2 may be molded from any desired material, for example, polycarbonate, acryl-styrene copolymer and acryl-butylene-styrene copolymer. On the outside of the partition 8 is attached a blood introduction port 7 having a blood inlet 10 in fluid communication with the inner space of the heat-exchange tubular means 6. The blood introduction port 7 is provided with a drug injection port 14 and a blood collection port 15. The blood introduction port 7 is mechanically mounted onto one end portion of the housing 2 by engagement. An O-ring disposed on the inner surface of the blood introduction port 7 comes into close contact with the outside surface of the periphery of the partition 8 to form a fluid tight seal between the blood introduction port 7 and the partition 8. The blood introduction port 7 may be welded to the housing 2 by ultrasonic or high frequency or may be bonded to the housing 2 with an adhesive. Alternatively, it may be fixed to the housing 2 with a fastening ring. As shown in Fig.1, the housing 2 has a large-diameter portion 2a at the portion where the partition 9 is disposed. Within the large-diameter portion 2a is provided a plurality of separated projections 5 projecting toward the nearer end opening of the housing 2 as shown in Figs.1 and 2. The partition 9 is secured to the inner surface of the large-diameter portion 2a of the housing 2. The projections 5 are positioned within the partition 9. The partition 9 has an annular area 9a at the periphery where the heat-exchange tubular means 6 is not present as shown in Figs.1 and 2. The projections 5 are positioned in the annular area 9a. As described above, even in the case of the heat exchanger 1 having the large-diameter portion 2a and the large annular area 9a where the heat-exchange tubular means 6 is not present, the potting composition is prevented from shrinking because the projections 5 are positioned in the annular area 9a of the partition 9. Thus, any separation between the partition 9 and the inner surface of the housing 2 due to shrinkage of the potting composition is prevented. It is also prevented to form a weak bond portion between the partition 9 and the inner surface of the housing 2. The partition 9 is preferably formed such that the entirety of the projections 5 is positioned therein. By this construction, if an impact is applied to the heat exchanger during operation, the impact to be applied to the projections 5 is absorbed because the entirety of the projections 5 is enclosed in the partition 9. It is thus prevented to peel the potting composition off the tips of the projections 5. It is preferred that more than two, more preferably more than four projections 5 are disposed nearly at regular intervals as shown in Fig.2. It is also preferred that the projections 5 are present at 1/30 to 1/1.5 of the periphery of the annular area where the projections 5 are disposed. Because the projections 5 are dispersed in the annular area and there is formed the area where the projections 5 are not present, the potting composition forming the partition 9 is not prevented from flowing in the housing 2 by the projections 5. The projections 5 are preferably located in the intermediate portion between the inner surface of the large-diameter portion 2a of the housing 2 and the circle formed by the outermost tubes of the heat-exchange tubular means 6 as shown in Fig.2. By this arrangement, shrinkage of the potting composition is effectively suppressed. The shape of the projections 5 is not limited to that shown in Fig.2. For example, it may be circular, elliptic, polygonal, star-shaped, etc. in its cross section. It is preferred that the projections 5 has the contact area with the partition 9 as large as possible. For this purpose, a large number of small projections may be formed on the surface of the projections 5 or the surface of the projections 5 may be roughed. The heat-exchange tubular means 6 is open at the end of the partition 9. A blood outlet which is the second fluid outlet is formed by the entirety of the heat-exchange tubular means 6 at the end of the partition 9. The end of the large-diameter portion 2a of the housing 2 is mechanically fitted to one end of a housing 21 of the artificial lung 20. The partition 9 of the heat exchanger 1 faces a partition 28 of the artificial lung 20. An O-ring 13 makes a fluid tight seal between the heat exchanger 1 and the artificial lung 20. The artificial lung 20 comprises a tubular housing 21, an assembly of gas-exchange hollow fibers 24 received in the tubular housing 21, and partitions 27 and 28 to which the opposed ends of the hollow fibers 24 are secured in a fluid tight seal. The interior of the tubular housing 21 is divided into a blood chamber and a gas chamber. The tubular housing 21 is provided with a gas inlet 22 and a gas outlet 23 in fluid communication with the gas chamber. On the Outside of the partition 27 at the end of the tubular housing 21, there is disposed a cap-like blood discharge port 25 having a blood outlet 26 in fluid communication with the inner spaces of the hollow fibers 24. Each hollow fiber 24 consists of a porous membrane having an inner diameter of 100 to 1,000 µm, a wall thickness of 5 to 200 µm, preferably 10 to 100 µm, and a porosity of 20 to 80%, preferably 30 to 60%, with pores having diameters of 0.01 to 5 µm, preferably 0.01 to 1 µm. About 5,000 to 100,000 hollow fibers are received in the housing 21 parallelly with the axis of the housing 21. The porous membrane of each hollow fiber is made of a hydrophobic polymeric material such as polypropyrene, polyethylene, polysulfone, polyacrylonitrile, polytetrafluoroethylene , and cellulose acetate. The porous membrane is preferably made of a polyolefinic resin, and most preferably polypropylene. The membrane is preferably formed from such a resin by a drawing or solid-liquid phase separation technique such that the membrane has pores formed in its wall. Next, an embodiment shown in Figs.3 and 4 will be described. The difference between this embodiment and the embodiment shown in Fig.1 is in the shape of the housing 2 and the configuration of the projections 5. Specifically, in the heat exchanger 1 of this embodiment, the large-diameter portion is not formed only at the end of the housing 2 but the housing 2 comprises a small-diameter tubular portion on the right side of the center of the housing 2 and a large-diameter tubular portion on the left side thereof. The large-diameter tubular portion on the left side of the center of the housing 2 has a constant inner diameter. Any larger-diameter portion is not formed therein. An annular member 40 including projections 5 is inserted in and fixed to the large-diameter tubular portion. The annular member 40 has eight projections extending in the radial direction toward the center of the annular member 40 as shown in Fig.3 and Fig.4 which is a cross section taken along line II-II of Fig.3. The eight projections are arranged at regular intervals. The tip end of each of the eight projections is cranked toward the nearer end opening of the housing 2 to constitute each projection 5 as shown in Fig.3. The annular member 40 is embedded in the partition 9 as shown in Fig.3. The construction of this embodiment except the housing 2 and the projections 5 is the same as that of the embodiment shown in Figs.1 and 2. Next, an embodiment shown in Figs.5 and 6 will be described. This embodiment differs from the embodiment shown in Fig.1 in the configuration of the projections 5. Specifically, In the heat exchanger 1 of this embodiment, the projections 5 formed in the heat exchanger housing 2 have reinforcement portions 5a. Each reinforcement portion connects a part of a side surface of the projection 5 on the inner surface side of the housing 2 to the inner surface of the housing 2 as shown in Fig.5 and Fig.6 which is a cross section taken along line III-III of Fig.5. The reinforcement portion 5a prevents the projection 5 from deforming toward the center of the housing 2 due to the shrinkage of the potting composition of the partition 9. Therefore, it can more effectively avoided to separate the partition 9 from the inner surface of the housing 2 due to the shrinkage of the partition 9. Although the fluid processing apparatus of the present invention has been described as being applied to a heat exchanger, it is also applicable to other artificial organ such as an artificial lung itself and an artificial kidney. Further, the fluid processing apparatus of the present invention is also applicable to a plasma separator. The fluid processing apparatus of the present invention is set in an extracorporeal circuit. For example, in an artificial lung equipped with a heat exchanger, blood introduced from the blood inlet 10 of the heat exchanger 1 flows in the heat-exchange tubular means 6 while hot or cool water introduced from the heat-exchange fluid inlet 3 of the housing 2 flows between the housing 2 and the heat-exchange tubular means 6. The blood is thus warmed or cooled and then flows out through the blood outlet formed by the entirety of the end of the tubular means 6. The blood then flows in the hollow fibers 24 through the blood inlet formed by the entirety of the end of the hollow fibers 24 which are open in the partition 28 of the artificial lung 20. On the other hand, oxygen-containing gas enters the artificial lung 20 from the gas inlet 22 of the housing 21 of the artificial lung 20. The blood comes into contact with the oxygen-containing gas through the hollow fibers 24 so that carbon dioxide is removed from and oxygen is added to the blood. The blood then flows out through the blood oulet 26. The fluid processing apparatus of the present invention comprises a housing having a first fluid inlet and a first fluid outlet; a fluid processing tubular means received in said housing; partitions securing the opposed ends of said fluid processing tubular means to said housing in a fluid tight seal to partition the housing interior into a first fluid chamber in fluid communication with said first fluid inlet and said first fluid outlet and a second fluid chamber defined in said fluid processing tubular means; a second fluid inlet and a second fluid outlet in fluid communication with said second fluid chamber; and projections formed on an inner surface of one end portion of said housing so as to project toward the nearer end opening of said housing, said partition of said one end portion side of said housing being secured to said one end portion of said housing so that said projections are positioned within said partition. Therefore, if a large annular portion where the fluid processing tubular means is not present is formed in the end portion of the housing, because the projections are positioned in the annular portion of the partition, shrinkage of the potting composition forming the partition is suppressed and any separation between the partition and the inner surface of the housing due to the shrinkage of the potting composition is prevented. Further, it is also prevented to form a weak bond portion between the partition and the inner surface of the housing. Further, if the entirety of the tip end of each projection is enclosed by the partition, an impact to be applied to that portion is absorbed so that it is prevented to peel off at the tip end of the projection.

Claims: A fluid processing apparatus (1) comprising a housing (2) having a first fluid inlet (3) and a first fluid outlet (4); a fluid processing tubular means (6) received in said housing; partitions (8, 9) made of a potting composition securing the opposed ends of said fluid processing tubular means (6) to opposed end portions of said housing in a fluid tight seal to partition the housing interior into a first fluid chamber in fluid communication with said first fluid inlet (3) and said first fluid outlet (4) and a second fluid chamber defined in said fluid processing tubular means; a second fluid inlet (10) and a second fluid outlet in fluid communication with said second fluid chamber; characterized in that a plurality of projections (5) are formed on an inner surface of one end portion of said housing so as to project toward said one end portion side of said housing, said plurality of projections (5) being dispersed in an annular area so that there is formed an area where said projections are not present, said partition (9) of the one end portion side of said housing being secured to said one end portion of said housing so that the entirety of said projections are positioned within said partition. A fluid processing apparatus according to claim 1, wherein said plurality of projections (5) are disposed at regular intervals in said annular area. A fluid processing apparatus according to claim 1 or 2, wherein each of said projections (5) has a reinforcement portion (5a) connecting at least a part of a side surface of the projection to an inner surface of said housing. A fluid processing apparatus according to claim 1 or 2, wherein said projections (5) are formed by an annular member inserted in said one end portion of said housing (2). A fluid processing apparatus according to anyone of claims 1 to 4, wherein an annular portion (9a) where said fluid processing tubular means (6) is not present is formed in the periphery of said partition (9) at said one end portion of said housing (2) and said projections (5) are positioned in said annular portion. A fluid processing apparatus according to anyone of claims 1 to 5, wherein a large-diameter portion (2a) is formed in at least said one end portion of said housing and said projections (5) are positioned within said large-diameter portion. A fluid processing apparatus according to claim 6, wherein said fluid processing tubular means (6) is heat-exchanger tubular means and said fluid processing apparatus is a heat-exchanger. An artificial lung (20) equipped with a heat exchanger (1) as set forth in claim 7, said artificial lung comprising an artificial lung housing (21) having a gas inlet (22) and a gas outlet (23); a bundle of gas-exchange hollow fibers (24) received in said artificial lung housing; partitions (27, 28) securing the opposed ends of said bundle of gas-exchange hollow fibers (24) to said artificial lung housing (21) in a fluid tight seal to partition the artificial lung housing interior into a gas chamber in fluid communication with said gas inlet and said gas outlet and a blood chamber defined in said gas-exchange hollow fibers; and a blood inlet portion and a blood outlet portion in fluid communication with said blood chamber, said partition (9) of said heat exchanger formed in said large-diameter end portion of said heat exchanger housing (2) facing one of said partitions (28) of said artificial lung (20) and the former being connected to the latter.

Inventors: ISHIKAWA KIYOHIDE, SAKAI SATORU, ISHIKAWA, KIYOHIDE, SAKAI, SATORU
Applicants: TERUMO CORP, TERUMO KABUSHIKI KAISHA
Application year: 1990
Main classification: A61M1
IPC codes: A61M1, B01D53, B01D63