CA1041025A - Air-blocking filter assembly - Google Patents
Air-blocking filter assemblyInfo
- Publication number
- CA1041025A CA1041025A CA224,420A CA224420A CA1041025A CA 1041025 A CA1041025 A CA 1041025A CA 224420 A CA224420 A CA 224420A CA 1041025 A CA1041025 A CA 1041025A
- Authority
- CA
- Canada
- Prior art keywords
- filter
- housing
- air
- hollow
- end wall
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
- A61M5/165—Filtering accessories, e.g. blood filters, filters for infusion liquids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D19/00—Degasification of liquids
- B01D19/0031—Degasification of liquids by filtration
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M2205/00—General characteristics of the apparatus
- A61M2205/75—General characteristics of the apparatus with filters
- A61M2205/7527—General characteristics of the apparatus with filters liquophilic, hydrophilic
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/36—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests with means for eliminating or preventing injection or infusion of air into body
- A61M5/38—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests with means for eliminating or preventing injection or infusion of air into body using hydrophilic or hydrophobic filters
Landscapes
- Health & Medical Sciences (AREA)
- Hematology (AREA)
- Heart & Thoracic Surgery (AREA)
- Vascular Medicine (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biomedical Technology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Chemical & Material Sciences (AREA)
- Anesthesiology (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Infusion, Injection, And Reservoir Apparatuses (AREA)
- Filtration Of Liquid (AREA)
- External Artificial Organs (AREA)
Abstract
AIR-BLOCKING FILTER ASSEMBLY
ABSTRACT OF THE DISCLOSURE
There is disclosed an air-blocking filter assembly having utility in delivering intravenous solutions. The filter has a substantially rectangularly shaped housing which prior to assembly has one end open. The ingress port for the filter assembly is located at the upper portion of the wall opposite the mentioned opening. The housing is closed by a closure which effectively comprises an end wall. The closure has a projecting hollow filter-supporting structure which is designed to abut the wall carrying the ingress port. The closure also carries the egress port which communicates with the internal portion of the hollow-supporting structure.
ABSTRACT OF THE DISCLOSURE
There is disclosed an air-blocking filter assembly having utility in delivering intravenous solutions. The filter has a substantially rectangularly shaped housing which prior to assembly has one end open. The ingress port for the filter assembly is located at the upper portion of the wall opposite the mentioned opening. The housing is closed by a closure which effectively comprises an end wall. The closure has a projecting hollow filter-supporting structure which is designed to abut the wall carrying the ingress port. The closure also carries the egress port which communicates with the internal portion of the hollow-supporting structure.
Description
- \ ` ` -10410~S
BACKGROUND OF THE INVENTION
It is know well-recognized that intravenous solutions which are to be infused must be filtered just before such infusion. It is well-known that such solution-containers and solution-administration sets contain quantities of particulate material in the um (micro meter) and sub um ranges, and air for a number of reasons, one being the fact that the solutions may contain solubilized air which may form bubbles. It is for this purpose that devices have been constructed to act as final filters prior to the infusion of such solutions. A well-known, highly-rated filter of this type is described in U. S. patent 3,471,019. This filter functions satisfactorily except when in certain positions an air bubble can spread over the surface of the hydrophilic filter thereby effectively cutting off further fluid flow. The present filter assembly is designated to obviate such and other difficulties by being position-insensitive.
SUMMARY OF THE INVENTION
The present invention is concerned with an air-blocking filter assembly for filtering intravenous solutions.
The device includes an open-ended, rectangularly-shaped housing.
The open end is closed by a plate which carries normally thereto a hollow filter structure which itself is open at the far end.
The plate has an egress tube communicating with the internal portion of the internal filter. The housing possesses an ingress tube at the opposite side to the opening. The hollow filter
BACKGROUND OF THE INVENTION
It is know well-recognized that intravenous solutions which are to be infused must be filtered just before such infusion. It is well-known that such solution-containers and solution-administration sets contain quantities of particulate material in the um (micro meter) and sub um ranges, and air for a number of reasons, one being the fact that the solutions may contain solubilized air which may form bubbles. It is for this purpose that devices have been constructed to act as final filters prior to the infusion of such solutions. A well-known, highly-rated filter of this type is described in U. S. patent 3,471,019. This filter functions satisfactorily except when in certain positions an air bubble can spread over the surface of the hydrophilic filter thereby effectively cutting off further fluid flow. The present filter assembly is designated to obviate such and other difficulties by being position-insensitive.
SUMMARY OF THE INVENTION
The present invention is concerned with an air-blocking filter assembly for filtering intravenous solutions.
The device includes an open-ended, rectangularly-shaped housing.
The open end is closed by a plate which carries normally thereto a hollow filter structure which itself is open at the far end.
The plate has an egress tube communicating with the internal portion of the internal filter. The housing possesses an ingress tube at the opposite side to the opening. The hollow filter
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`\~ 3~ructure is sufficiently long whereby it extends to the end wall carrying the ingress tube but displaced therefrom. The filter structure is secured to the said wall and the mentioned plate is secured into the opening to enclose the housing. ~he filter assembly is essentially constructed of two plastic, in-tegrally-molded pieces. The actual filter material is secured over a rib cage to produce the stated hollow filter structure.
Thereafter, the two pieces are easily and inexpensively assembled and adhered under the aegis of ultrasonic welding, or thermal sealing, or solvent sealing to thereby result in the filter assem-bly of the present invention. The herein-disclosed filter will permit, under practically all conditions at least some solution to continue to flow since at least a portion of the filter surface will remain in contact with the solution regardless of position.
In one particular aspect the present invention provides an air-blocking filter comprising a cylindrical housing having spaced end walls, a filter element defining a hollow chamber ex-tending across the housing and into the housing, said filter ele-ment being hydrophilic and adapted to pass liquid and block air when wetted with liquid and being positioned in the housing so as to be wetted by any liquid in the housing, ingress means communi-cating with the housing and egress means communicating with the chamber whereby liquid is passed through the housing and the fil-ter for discharge through the egress means while air is blocked from passing through the wetted filter.
In another particular aspect the present invention provides an air-blocking filter comprising a housing, said housing having a top, a bottom, side walls and an end wall, and an opening opposite the side of the housing having-the end wall, said end wall having an ingress port, a filter-support means, said filter-support means having a plate arranged and constructed to mate with said opening in said housing to thereby enclose said housing, a ~ -3-,~ jc/~
- . ~ - ., .: . -~410~5 - hydrophilic filter mounted on the filter-support means, said plate having an egress port on the outside thereof; and said plate having projecting from the other side a hollow filter open-ended structure extendlng into said housing and terminating in abutment with the inside of said end wall of the housing and displaced from said ingress port, with the filter positioned in the housing so as to be wetted by any liquid contained in the housing whereby the wetted filter passes liquid therethrough while blocking air.
BRIEF DESCRIPTION OF THE DR~WINGS
Figure 1 is a side elevation of the filter assembly of the present invention.
Figure 2 is a perspective exploded view of the fi~ter assembly.
Figure 3 is a top-plan view of the filter per se.
Figure 4 is a cross-sectional view taken along line 4-4 of Figure 2 with the elements in an assembled condition.
Figure 5 is a top-plan view of the housing for the ' filter.
Figure 6 is an end view of the filter.
Figure 7 is an enlargement of a portion of Figure 4.
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DETAILED DESC~IPTION OF THE INVENTION
Now, turning to the figures illustrating the preferred embodiment of the invention, attention is directed to reference numeral 10 which depicts the filter assembly of the present invention generally. The filter assembly is shown in Figure 1 to be connected to a conduit which carries the filtered liquid, that is, intravenous solution, away from the filter in the direc-tion of utilization which, of course, will be in a patient. The conduit 11 is connected to an egress tube 12 (shown by dotted lines in Figure 1). The filter assembly also has an ingress tube 13.
Attention is now directed to Figure 2 for greater elucidation of the filter assembly. Note that the filter assem-bly comprises essentially two parts. The filter assembly 10 has a generally rectangularly-shaped housing 14, having a top 15, a bottom 16, front wall 17, and back wall 18. It also has an end wall 19, seen better in Figure 4. The top and bottom have longitudinally-disposed, elongated concavities, thereby making it easier to tape the filter assembly to the lower portion of a patient's arm. It will be appreciated that from Figure 2, the housing 14 is open at 20 at one end.
The opening is opposite the end wall 19 which also carries the ingress tube 13 which is normal to the end wall. The opening 20 is defined by the top, bottom, front and back walls, respectively. The just-mentioned elements, together, also produce shoulder 21 having a raised portion facing outwardly to form an energy ring 31 to facilitate ultrasonic welding.
When ultrasonic energy is applied to the energy ring it tends to flatten and seal against the material in abutment therewith.
Figure 7 illustrates the energy ring. Turning to Figure 4, it will also be discerned that internally of end wall 19 is a well : ;
~o~
22, arranged and constructed to accept one end of the filter 23, more about which will be imparted below~
The ingress tube 13 is formed integral with respect to the housing. The tube possesses an internal bore 24 which convgrges inwardly. The tube 13 is connected to a conduit (not shown) which is the source of fluid, that is, intravenous solution which is to be subjected to the filtering action or the present invention. The mentioned conduit also has a taper and an outer diameter matching the taper and diameter of the bore 24. The conduit, in other words, is secured internally with respect to the bore by friction fit. The conduit may be a friction fit or may be more permanently implanted in the tube 13 as by heat-sealing, or by solvent adhesion, all well-known and useful methods.
Figure 5 illustrates the housing 14 by means of a top-plan view. Of interest to the instant matter is the fact that the housing may be constructed by means of injection-moulding techniques. Propitiously, it has been found favorable to employ a plastic material such as polystyrene, ABS plastic, or an acrylic resin. Furthermore, the preferred synthetic plastic material is a transparent material whereby the filter assembly of the present invention finds utility as a means for determining the presence of solution or air in the assembly, Now, attention is directed to the filter 23, in order to complete the understanding of the invention. First, Figures 2 and 3 should be considered. T~e filter 23 is arranged and constructed to present an in-line filter surface. The filter 23 has a plate 25 which has a configuration and suitable dimensions to constitute an end wall for heretofore mentioned opening 20. On one side of the plate 25, normal thereto, is the egress tube 12. On the other side of the plate and also normal thereto, is a hexagonal structure 26 which has six ribs 27 1~4.~S
shown by dotted lines in Figure 3~ The preferred embodiment herein described relates to a hexagonal configuration. However, it is contemplated that many other shapes, for example, square, circular or the like, structures are within the purview of the inventive concept and the number of ribs may be adjusted accordingly. A microporous filter membrane 28 extends over and between the ribs 27 to enclose the hexagonal structure 26. The hexagonal structure terminates in a hollow hexagonal ring 28 which is integrally attached to a rectangular plate 29. The hexagonal structure also terminates in a hexagonal ring 30 ~
which is integrally secured to the backside of plate 25. The filter memhrane is hydrophilic and is reinforced with a screen material, such as, nylon, polyester or other suitable organic or inorganic materials. It has a nominal pore size of 0.45 um (micro meters), but other sizes, larger or smaller, may be used.
For example, it should be possible to use a pore size from between .1 um to 14 um. The filter membrane can be a sleeve or in strip form and attached to the ribs 27 and the hexagonal rings 28 and 30 by thermal means, during the molding cycle of the support structure, for instance. It has been expeditious to apply the membrane during the molding step as the support structure will be soft and the membrane will adhere when it is cooled. The rectangular plate 29 is adapted to fit into the well 22 of end wall 19 of the housing when the filter assembly is assembled.
The plate 29 does not cover the end portion of the hollow hexagonal structure as can be seen from Figure 6. The ends of the ribs 27 may be seen in the figure as well as the bore of egress tube 12. The internal surface of the well 22 and the end wall 19 thereof serve to close the end of the hexa-gonal structure 26. The entire structure of the filter 23, except for the microporous membrane, may be constructed by injection molding of synthetic resin or plastic material.
. .~ .:
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Attention is now specifically directed to Figure 4 to illustrate the assemblage. The plate 25 mates in the shoulder 21 of the housing against the energy ring 31 and is secured by ultrasonic welding, for instance. As was mentioned before, the plate 29 is designed to snugly fit into the well 22. The plate 29, as can be seen from Figure 6, also possesses a raised energy ring 32. The plate 29 is also firmly secured as by ultrasonic welding, for instance. Both plates can be joined to their mating surfaces simultaneously, incorporating the technique of near- and far-field ultrasonic welding. During the welding step, the energy rings become molten causing those areas to bond to their mating surfaces upon cooling The outer surface of egress tube 12 is tapered to more easily accept the conduit 11 which is positioned outermost of egress tube 12.
Liqu~d flowing into the filter assembly of the present invention is usefully cleared of small particulate material which may be deposited on the surface of the microporous membrane material on the outside of the hexagonal structure or trapped in the membrane pores. The device is designed to provide excellent filter surface area in the confines of a relatively qmall filter assembly wherein the microporous membrane material is adequately supported so that the mer,lbrane is not b~rst under the normal pressures encountered during gravity infusion of solutions of the liquid. Also, the ingress and egress tubes are arranged and constructed so that the connections made to the filter assembly are in a manner to avoid sharp corners.
As stated heretofore, even with a large quantity of air in the filter aqsembly, there will be at leaqt a degree of useful filter area through which some liquid may flow. The air will not pass through the filter because the membrane is hydrophilic.
Also, the air will not be able to totally block the filter because of access to the liquid along 360, so that the filter ,. : :: . .. . . . .. -: . . :, lC~
operates even when turned in any direction or position unless, of course, the entire filter unit has been filled with air.
The fact that the housing 14 is preferably transparent makes it possible to see whether or not there is any accumulated air.
The filter of the present invention may be easily purged of excess air by momentarily disconnecting the conduit at ingress port 13 to permit the air to be replaced therethrough while liquid is still permitted to flow into the filter.
From a consideration of the present invention, it will be appreciated that the filter assembly may be employed in a reverse-flow manner. Of course, in such an instance, it would be wise to change the structure of the ingress and egress ports.
One of the primary advantages of the present invention is that the air-blocking filter of the invention is position-insensitive, that is, it is capable of passing liquid through the hydrophilic filter and blocking air no matter how the filter is disposed provided that the filter has been wetted with the liquid.
The position insensitivity of the filter of the inv~tion is assured by the geometry of the housing 14 and the geometry of the filter 23. As shown in Figure 2, the housing is cylindrical in shape; as used herein, the term ncylindrical" is intended to refer to and include a surface traced by a straight line moving parallel to a fixed ~traight line. The cross-section of the housing can thus be circular or polygonal in shape.
The filter 23 has a relatively flat configuration defining a hollow chamber; the filter extends substantially across the cross-section and extends longitudinally into the housing 14 to insure maximum surface area of the membrane 28.
The inlet or ingress means 13 is accordingly positioned to discharge liquid onto the surface of the membrane 28 to wet .j 8 lQ~ S
the filter when the filter lO is disposed in the position shown in Figures 2 and 4. If the filter is turned in any direction, as by a change in position of a patient to which the filter is fixed during intravenous administration, liquid contained in the housing 14 continues to wet at least a portion of the surface of the membrane 28. As long as the hydrophilic filter or membrane 28 remains wetted by the liquid, it will pass liquid through the pores thereof while blocking air or like gases. The filter of the invention will thus continue to pass liquid and block air if and untll the housing becomes completely filled with air so as to no longer permit the filter to be wetted with air. If such a point is reached, the air may be bled from the system, as by removal of a tubing on the inlet or ingress means, or by other such suitakle means.
., - - , , - . . .. -.
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S
,~
`\~ 3~ructure is sufficiently long whereby it extends to the end wall carrying the ingress tube but displaced therefrom. The filter structure is secured to the said wall and the mentioned plate is secured into the opening to enclose the housing. ~he filter assembly is essentially constructed of two plastic, in-tegrally-molded pieces. The actual filter material is secured over a rib cage to produce the stated hollow filter structure.
Thereafter, the two pieces are easily and inexpensively assembled and adhered under the aegis of ultrasonic welding, or thermal sealing, or solvent sealing to thereby result in the filter assem-bly of the present invention. The herein-disclosed filter will permit, under practically all conditions at least some solution to continue to flow since at least a portion of the filter surface will remain in contact with the solution regardless of position.
In one particular aspect the present invention provides an air-blocking filter comprising a cylindrical housing having spaced end walls, a filter element defining a hollow chamber ex-tending across the housing and into the housing, said filter ele-ment being hydrophilic and adapted to pass liquid and block air when wetted with liquid and being positioned in the housing so as to be wetted by any liquid in the housing, ingress means communi-cating with the housing and egress means communicating with the chamber whereby liquid is passed through the housing and the fil-ter for discharge through the egress means while air is blocked from passing through the wetted filter.
In another particular aspect the present invention provides an air-blocking filter comprising a housing, said housing having a top, a bottom, side walls and an end wall, and an opening opposite the side of the housing having-the end wall, said end wall having an ingress port, a filter-support means, said filter-support means having a plate arranged and constructed to mate with said opening in said housing to thereby enclose said housing, a ~ -3-,~ jc/~
- . ~ - ., .: . -~410~5 - hydrophilic filter mounted on the filter-support means, said plate having an egress port on the outside thereof; and said plate having projecting from the other side a hollow filter open-ended structure extendlng into said housing and terminating in abutment with the inside of said end wall of the housing and displaced from said ingress port, with the filter positioned in the housing so as to be wetted by any liquid contained in the housing whereby the wetted filter passes liquid therethrough while blocking air.
BRIEF DESCRIPTION OF THE DR~WINGS
Figure 1 is a side elevation of the filter assembly of the present invention.
Figure 2 is a perspective exploded view of the fi~ter assembly.
Figure 3 is a top-plan view of the filter per se.
Figure 4 is a cross-sectional view taken along line 4-4 of Figure 2 with the elements in an assembled condition.
Figure 5 is a top-plan view of the housing for the ' filter.
Figure 6 is an end view of the filter.
Figure 7 is an enlargement of a portion of Figure 4.
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3a . ', ' ~ j C / ~
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DETAILED DESC~IPTION OF THE INVENTION
Now, turning to the figures illustrating the preferred embodiment of the invention, attention is directed to reference numeral 10 which depicts the filter assembly of the present invention generally. The filter assembly is shown in Figure 1 to be connected to a conduit which carries the filtered liquid, that is, intravenous solution, away from the filter in the direc-tion of utilization which, of course, will be in a patient. The conduit 11 is connected to an egress tube 12 (shown by dotted lines in Figure 1). The filter assembly also has an ingress tube 13.
Attention is now directed to Figure 2 for greater elucidation of the filter assembly. Note that the filter assem-bly comprises essentially two parts. The filter assembly 10 has a generally rectangularly-shaped housing 14, having a top 15, a bottom 16, front wall 17, and back wall 18. It also has an end wall 19, seen better in Figure 4. The top and bottom have longitudinally-disposed, elongated concavities, thereby making it easier to tape the filter assembly to the lower portion of a patient's arm. It will be appreciated that from Figure 2, the housing 14 is open at 20 at one end.
The opening is opposite the end wall 19 which also carries the ingress tube 13 which is normal to the end wall. The opening 20 is defined by the top, bottom, front and back walls, respectively. The just-mentioned elements, together, also produce shoulder 21 having a raised portion facing outwardly to form an energy ring 31 to facilitate ultrasonic welding.
When ultrasonic energy is applied to the energy ring it tends to flatten and seal against the material in abutment therewith.
Figure 7 illustrates the energy ring. Turning to Figure 4, it will also be discerned that internally of end wall 19 is a well : ;
~o~
22, arranged and constructed to accept one end of the filter 23, more about which will be imparted below~
The ingress tube 13 is formed integral with respect to the housing. The tube possesses an internal bore 24 which convgrges inwardly. The tube 13 is connected to a conduit (not shown) which is the source of fluid, that is, intravenous solution which is to be subjected to the filtering action or the present invention. The mentioned conduit also has a taper and an outer diameter matching the taper and diameter of the bore 24. The conduit, in other words, is secured internally with respect to the bore by friction fit. The conduit may be a friction fit or may be more permanently implanted in the tube 13 as by heat-sealing, or by solvent adhesion, all well-known and useful methods.
Figure 5 illustrates the housing 14 by means of a top-plan view. Of interest to the instant matter is the fact that the housing may be constructed by means of injection-moulding techniques. Propitiously, it has been found favorable to employ a plastic material such as polystyrene, ABS plastic, or an acrylic resin. Furthermore, the preferred synthetic plastic material is a transparent material whereby the filter assembly of the present invention finds utility as a means for determining the presence of solution or air in the assembly, Now, attention is directed to the filter 23, in order to complete the understanding of the invention. First, Figures 2 and 3 should be considered. T~e filter 23 is arranged and constructed to present an in-line filter surface. The filter 23 has a plate 25 which has a configuration and suitable dimensions to constitute an end wall for heretofore mentioned opening 20. On one side of the plate 25, normal thereto, is the egress tube 12. On the other side of the plate and also normal thereto, is a hexagonal structure 26 which has six ribs 27 1~4.~S
shown by dotted lines in Figure 3~ The preferred embodiment herein described relates to a hexagonal configuration. However, it is contemplated that many other shapes, for example, square, circular or the like, structures are within the purview of the inventive concept and the number of ribs may be adjusted accordingly. A microporous filter membrane 28 extends over and between the ribs 27 to enclose the hexagonal structure 26. The hexagonal structure terminates in a hollow hexagonal ring 28 which is integrally attached to a rectangular plate 29. The hexagonal structure also terminates in a hexagonal ring 30 ~
which is integrally secured to the backside of plate 25. The filter memhrane is hydrophilic and is reinforced with a screen material, such as, nylon, polyester or other suitable organic or inorganic materials. It has a nominal pore size of 0.45 um (micro meters), but other sizes, larger or smaller, may be used.
For example, it should be possible to use a pore size from between .1 um to 14 um. The filter membrane can be a sleeve or in strip form and attached to the ribs 27 and the hexagonal rings 28 and 30 by thermal means, during the molding cycle of the support structure, for instance. It has been expeditious to apply the membrane during the molding step as the support structure will be soft and the membrane will adhere when it is cooled. The rectangular plate 29 is adapted to fit into the well 22 of end wall 19 of the housing when the filter assembly is assembled.
The plate 29 does not cover the end portion of the hollow hexagonal structure as can be seen from Figure 6. The ends of the ribs 27 may be seen in the figure as well as the bore of egress tube 12. The internal surface of the well 22 and the end wall 19 thereof serve to close the end of the hexa-gonal structure 26. The entire structure of the filter 23, except for the microporous membrane, may be constructed by injection molding of synthetic resin or plastic material.
. .~ .:
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Attention is now specifically directed to Figure 4 to illustrate the assemblage. The plate 25 mates in the shoulder 21 of the housing against the energy ring 31 and is secured by ultrasonic welding, for instance. As was mentioned before, the plate 29 is designed to snugly fit into the well 22. The plate 29, as can be seen from Figure 6, also possesses a raised energy ring 32. The plate 29 is also firmly secured as by ultrasonic welding, for instance. Both plates can be joined to their mating surfaces simultaneously, incorporating the technique of near- and far-field ultrasonic welding. During the welding step, the energy rings become molten causing those areas to bond to their mating surfaces upon cooling The outer surface of egress tube 12 is tapered to more easily accept the conduit 11 which is positioned outermost of egress tube 12.
Liqu~d flowing into the filter assembly of the present invention is usefully cleared of small particulate material which may be deposited on the surface of the microporous membrane material on the outside of the hexagonal structure or trapped in the membrane pores. The device is designed to provide excellent filter surface area in the confines of a relatively qmall filter assembly wherein the microporous membrane material is adequately supported so that the mer,lbrane is not b~rst under the normal pressures encountered during gravity infusion of solutions of the liquid. Also, the ingress and egress tubes are arranged and constructed so that the connections made to the filter assembly are in a manner to avoid sharp corners.
As stated heretofore, even with a large quantity of air in the filter aqsembly, there will be at leaqt a degree of useful filter area through which some liquid may flow. The air will not pass through the filter because the membrane is hydrophilic.
Also, the air will not be able to totally block the filter because of access to the liquid along 360, so that the filter ,. : :: . .. . . . .. -: . . :, lC~
operates even when turned in any direction or position unless, of course, the entire filter unit has been filled with air.
The fact that the housing 14 is preferably transparent makes it possible to see whether or not there is any accumulated air.
The filter of the present invention may be easily purged of excess air by momentarily disconnecting the conduit at ingress port 13 to permit the air to be replaced therethrough while liquid is still permitted to flow into the filter.
From a consideration of the present invention, it will be appreciated that the filter assembly may be employed in a reverse-flow manner. Of course, in such an instance, it would be wise to change the structure of the ingress and egress ports.
One of the primary advantages of the present invention is that the air-blocking filter of the invention is position-insensitive, that is, it is capable of passing liquid through the hydrophilic filter and blocking air no matter how the filter is disposed provided that the filter has been wetted with the liquid.
The position insensitivity of the filter of the inv~tion is assured by the geometry of the housing 14 and the geometry of the filter 23. As shown in Figure 2, the housing is cylindrical in shape; as used herein, the term ncylindrical" is intended to refer to and include a surface traced by a straight line moving parallel to a fixed ~traight line. The cross-section of the housing can thus be circular or polygonal in shape.
The filter 23 has a relatively flat configuration defining a hollow chamber; the filter extends substantially across the cross-section and extends longitudinally into the housing 14 to insure maximum surface area of the membrane 28.
The inlet or ingress means 13 is accordingly positioned to discharge liquid onto the surface of the membrane 28 to wet .j 8 lQ~ S
the filter when the filter lO is disposed in the position shown in Figures 2 and 4. If the filter is turned in any direction, as by a change in position of a patient to which the filter is fixed during intravenous administration, liquid contained in the housing 14 continues to wet at least a portion of the surface of the membrane 28. As long as the hydrophilic filter or membrane 28 remains wetted by the liquid, it will pass liquid through the pores thereof while blocking air or like gases. The filter of the invention will thus continue to pass liquid and block air if and untll the housing becomes completely filled with air so as to no longer permit the filter to be wetted with air. If such a point is reached, the air may be bled from the system, as by removal of a tubing on the inlet or ingress means, or by other such suitakle means.
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., .. ~ .
Claims (15)
1. An air-blocking filter comprising a cylindrical housing having spaced end walls, a filter element defining a hollow chamber extending across the housing and into the housing, said filter element being hydrophilic and adapted to pass liquid and block air when wetted with liquid and being positioned in the housing so as to be wetted by any liquid in the housing, ingress means communicating with the housing and egress means communicating with the chamber whereby liquid is passed through the housing and the filter for dis-charge through the egress means while air is blocked from passing through the wetted filter.
2. A filter as defined in claim 1 wherein the filter element is positioned in abutment with the end walls, and the ingress means is positioned in one of the end walls.
3. A filter as defined in claim 1 wherein the filter element has a substantially flat, hexagon configuration.
4. A filter as defined in claim 3 wherein the filter element includes an elongated rib cage at the corners of the hexagon, with the rib cage being covered with hydrophilic filter material.
5. A filter as defined in claim 1 wherein the filter element has a pore size within the range of 0.1 um to 14 um.
6. A filter as defined in claim 1 wherein the housing is formed of a cylinder having a substantially rectangular cross-section, with the filter element extending across the longest dimension of the cross-section.
7. An air-blocking filter comprising a housing, said housing having a top, a bottom, side walls and an end wall, and an opening opposite the side of the housing having the end wall, said end wall having an ingress port, a filter-support means, said filter-support means having a plate arranged and constructed to mate with said opening in said housing to thereby enclose said housing, a hydrophilic filter mounted on the filter-support means, said plate having an egress port on the outside thereof; and said plate having projecting from the other side a hollow filter open-ended structure extending into said housing and terminating in abutment with the inside of said end wall of the housing and displaced from said ingress port, with the filter positioned in the housing so as to be wetted by any liquid contained in the housing whereby the wetted filter passes liquid therethrough while blocking air.
8. The filter assembly of claim 7 wherein the said hollow-filter structure has a hexagonal configuration.
9. The filter assembly of claim 8 wherein the hollow filter structure includes an elongated rib cage at the corners of the hexagon and the rib cage is covered with filter material.
10. The filter assembly of claim 9 wherein the filter material is hydrophilic and has a pore size of between 0.1 um to 14 um.
11. The filter assembly of claim 9 wherein the hollow-filter structure is open-ended and the said end wall has a recess adapted and constructed to retain the portion of the hollow-filter structure that is in abutment with the end wall.
12. The filter assembly of claim 11 wherein the top and bottom of said housing each has an elongated longitudinal concavity from the end wall to the said plate.
13. The filter assembly of claim 11 wherein the said housing around the said opening thereof has a shoulder adapted and constructed into which said plate is mounted.
14. The filter assembly of claim 11 wherein the hollow filter structure at the open-ended portion has an out-wardly extending flange and said recess is adapted and con-structed to retain said flange.
15. The filter assembly of claim 1 wherein the housing is transparent.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US46409074A | 1974-04-25 | 1974-04-25 | |
| US50569174A | 1974-09-13 | 1974-09-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1041025A true CA1041025A (en) | 1978-10-24 |
Family
ID=27040839
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA224,420A Expired CA1041025A (en) | 1974-04-25 | 1975-04-11 | Air-blocking filter assembly |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS515891A (en) |
| CA (1) | CA1041025A (en) |
| DK (1) | DK505474A (en) |
| FI (1) | FI283274A (en) |
| FR (1) | FR2268549A1 (en) |
| IL (1) | IL47090A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4515606A (en) * | 1981-03-19 | 1985-05-07 | Brunswick Corporation | Gas separating and venting filter |
| DE3628136A1 (en) * | 1986-08-19 | 1988-03-24 | Escher Wyss Gmbh | Separation apparatus for relatively light components of a liquid stream |
| JPH01179598A (en) * | 1988-01-11 | 1989-07-17 | Nippon Telegr & Teleph Corp <Ntt> | Remote control method for use stoppage and use stoppage cancellation |
-
1974
- 1974-09-25 DK DK505474A patent/DK505474A/en not_active Application Discontinuation
- 1974-09-27 FI FI2832/74A patent/FI283274A/fi unknown
-
1975
- 1975-04-11 CA CA224,420A patent/CA1041025A/en not_active Expired
- 1975-04-14 IL IL47090A patent/IL47090A/en unknown
- 1975-04-19 JP JP50048098A patent/JPS515891A/ja active Pending
- 1975-04-24 FR FR7512782A patent/FR2268549A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| FI283274A (en) | 1975-10-26 |
| DK505474A (en) | 1975-10-26 |
| JPS515891A (en) | 1976-01-19 |
| IL47090A (en) | 1978-04-30 |
| FR2268549A1 (en) | 1975-11-21 |
| IL47090A0 (en) | 1975-06-25 |
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