VENTED ADAPTER
United States Patent 3830241
A vented drainage system including a drainage tube having a lumen for passage of fluid and an opening in the wall of the tube, a vent for the tube communicating between the atmosphere and the tube opening, and an air permeable filter element positioned in the vent to filter air passing through the vent to the tube lumen. The drainage system has a section of flexible tubing positioned in the drainage tube with one end thereof on the upstream side of the opening in the wall of the drainage tube and the other end on the downstream side of the opening. The tubing has an outside diameter approximately equal to the inside diameter of the drainage tube to provide interfacial contact between the outside surface of the tubing and the inside surface of the tube to prevent passage of fluid between the interfacial surfaces thereof. The tubing is flexible to become disengaged from contact with the inner surface of the tube to provide a passageway for air to flow from the vent into the lumen when the pressure in the tube is less than atmospheric.
US Patent References:
Valve
Langdon - March 1945 - 2371449
Surgical wound drain having an inner collapsible tube preventing reverse flow into the wound
Shriner - May 1968 - 3384089
Syringe valve
Von Dardel et al. - December 1968 - 3416567
SELF-SEALING VALVE ASSEMBLY
Barrett et al. - March 1970 - 3498321
DRAINAGE CONTROL
Anderson et al. - August 1971 - 3598124
Valve
Langdon - March 1945 - 2371449
Surgical wound drain having an inner collapsible tube preventing reverse flow into the wound
Shriner - May 1968 - 3384089
Syringe valve
Von Dardel et al. - December 1968 - 3416567
SELF-SEALING VALVE ASSEMBLY
Barrett et al. - March 1970 - 3498321
DRAINAGE CONTROL
Anderson et al. - August 1971 - 3598124
Inventors:
Dye, John F. (Barrington, IL)
Binard, William J. (Barrington, IL)
Binard, William J. (Barrington, IL)
Application Number:
05/278318
Publication Date:
08/20/1974
Filing Date:
08/07/1972
View Patent Images:
Export Citation:
Assignee:
The Kendall Company (Walpole, MA)
Primary Class:
Other Classes:
137/526, 137/853, 137/217, 285/924
International Classes:
A61F5/441; A61M25/00
Field of Search:
128/349R,35R,348,276,295,274,275 137/217,218,526,525,512.15
US Patent References:
| 3690315 | COMBINED CONTAINER AND PACKAGE PARTICULARLY ADAPTED FOR URINARY DRAINAGE ASSEMBLIES | September 1972 | Chittenden et al. |
Primary Examiner:
Truluck, Dalton L.
Attorney, Agent or Firm:
Sprunger, Powell L.
Claims:
We claim
1. A vented adapter for a body fluid drainage system comprising:
2. The vented adapter of claim 1 wherein the second tubular section is positioned downstream from the first tubular section, said one end of the flexible tube is secured to the downstream end of the first tubular section, and the free end of the flexible tube is received in the upstream end of the second tubular section.
3. A vented adapter for a liquid drainage system comprising:
4. The vented adapter of claim 3 wherein said filtering and passing means comprises an air permeable filter element secured to the flange and extending peripherally around the second tubular section.
5. The vented adapter of claim 3 wherein said tube is removably secured to the first tubular section, and said flange is removably attached to the annular rim.
6. The vented adapter of claim 1 including means for filtering air passing into said chamber.
1. A vented adapter for a body fluid drainage system comprising:
2. The vented adapter of claim 1 wherein the second tubular section is positioned downstream from the first tubular section, said one end of the flexible tube is secured to the downstream end of the first tubular section, and the free end of the flexible tube is received in the upstream end of the second tubular section.
3. A vented adapter for a liquid drainage system comprising:
4. The vented adapter of claim 3 wherein said filtering and passing means comprises an air permeable filter element secured to the flange and extending peripherally around the second tubular section.
5. The vented adapter of claim 3 wherein said tube is removably secured to the first tubular section, and said flange is removably attached to the annular rim.
6. The vented adapter of claim 1 including means for filtering air passing into said chamber.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to vented liquid drainage systems.
2. Description of the Prior Art
It is known that in systems for the drainage of fluids from the body, such as indwelling catheters, a negative pressure may be created in such systems which has a deleterious effect on the body. To alleviate this result, Ericson U.S. Pat. No. 3,429,314 discloses a vented drainage system which prevents buildup of a negative pressure, and shows a filter unit positioned in the vent to prevent the passage of bacteria into the system. However, if fluids in the system contact the filter unit, it may be rendered inoperable, and Ericson U.S. Pat. No. 3,419,009 teaches the use of a valve to protect the filter. In an application filed June 2, 1971, Ser. No. 149,315, U.S. Pat. No. 3,730,209, entitled "Vent for Liquid Drainage System" we disclosed a vented adapter.
SUMMARY OF THE INVENTION
The principal feature of the present invention is a vented drainage system having tubular sections interfitting with each other to provide intimate interfacial contact sufficient to prevent the passage of liquid between the interfacial surfaces thereof, one of the sections being flexible and responsive to a pressure differential between the inside of the sections when filled with liquid and the atmosphere on the outside of the sections to cause the flexible tubular section to flex and to become disengaged from interfacial contact with the other section to provide a passageway for the passage of air therebetween. The passageway communicates with the atmosphere to relieve the pressure differential.
The invention will first be described embodied in a new and improved vented adapter of simplified construction for in-line use in a liquid drainage system.
The vented adapter of the present invention has a body member and a section of flexible tube received in the body member. The body member includes first and second tubular sections, each of which has a drainage lumen. The second tubular section is spaced from and positioned downstream from the first tubular section with their lumens being generally aligned. The flexible tube has one end secured to the downstream end of the first tubular section and the other free end received in the lumen of the second tubular section, and the outside diameter of the free tube end is approximately equal to the inside diameter of the second tubular section.
A feature of the present invention is that the tube communicates between the lumens in the first and second tubular sections.
Another feature of the invention is that the free tube end engages the inside of the second tubular section to prevent the escape of drainage liquid from the system.
A further feature of the invention is that the free tube end flexes to permit passage of air into the drainage lumen of the second tubular section.
The body member includes an annular rim extending outwardly and downstream from the first tubular section, and a flange extending radially outwardly from the second tubular section and attached to the rim, such that the rim and flange define a chamber containing the downstream end of the first tubular section and an upstream portion of the tube. An air permeable filter element is secured to the flange and extends peripherally around the second tubular section.
Another feature of the present invention is the provision of relatively large filter means to filter and pass air for venting the system.
A further feature of the invention is that the flange may be removably attached to the annular rim and the tube may be removably secured to the first tubular section, in order that the second tubular section may be removed from the adapter to secure a drainage tube in the liquid drainage system directly to the downstream end of the first tubular section.
Further features will become more fully apparent in the following description of the embodiments of this invention and from the appended claims.
DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a fragmentary perspective view of a liquid drainage system, including the vented adapter of the present invention;
FIG. 2 is a fragmentary elevational view, taken partially in section, of the liquid drainage system and adapter of FIG. 1;
FIG. 3 is a sectional view taken substantially as indicated along the line 3--3 of FIG. 2;
FIG. 4 is a sectional view of a portion of the adapter of FIG. 2 with a drainage tube in the liquid drainage system secured to the adapter in a non-vented configuration;
FIG. 5 is a fragmentary sectional view of another embodiment of the present invention; and
FIG. 6 is a fragmentary sectional view of another embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention relates generally to liquid drainage systems, such as systems for draining liquid from the body cavity of a patient, which are vented to the atmosphere to alleviate negative pressure which may develop in the systems. The invention will first be described embodied in a vented adapter for in-line use in a liquid drainage system.
Referring now to FIGS. 1 and 2, a liquid drainage system, generally designated 10, is shown including an interconnected catheter 12, an adapter designated generally 14, and a drainage tube 16. During use of the drainage system 10, the distal end of the catheter (not shown) is inserted into the body cavity of a patient, such as the bladder, and liquid drains through a lumen 18a in the catheter 12, as shown in FIG. 2, through the adapter 14, and through a lumen 18b in the drainage tube 16 to a receptacle (not shown) for collection.
The adapter 14 of the present invention has a relatively rigid body member, generally designated 20, which includes first and second spaced tubular sections 22 and 24, respectively. The first tubular section 22 has a longitudinally extending drainage lumen 18c and the upstream end 26 of the first tubular section 22 is received in the proximal end 28 of the catheter 12, such that the lumen 18c communicates with the lumen 18a in the catheter. The second tubular section 24 has a longitudinally extending drainage lumen 18d, and the tubular section 24 is received in the drainage tube 16 with the lumen 18d communicating with the lumen 18b in the drainage tube. The first and second tubular sections 22 and 24 are positioned in the body member 20 with their respective drainage lumens 18c and 18d being generally aligned with each other.
The body member 20 has an annular rim 30 which extends outwardly from the first tubular section 22 intermediate its ends and which extends downstream from the first tubular section. The body member 20 also has a flange 32 extending radially outwardly from the upstream end of the second tubular section 24, and which is secured to the rim 30, such as by gluing or heat sealing the flange 32 in an annular groove 34 in the rim 30. However, it is contemplated that the flange 32 may be removably attached to the rim 30, such as by snap-fitting the flange and rim together in sealing engagement. Also, the flange 32 and rim 30 may be integral with each, such that the rim may be secured to the first tubular section 22 adjacent the juncture of the rim and the first tubular section.
The rim 30 and flange 32 constitutes a housing defining a chamber 36 which contains the downstream end 38 of the first tubular section 22. As shown in FIGS. 2 and 3, an air permeable filter element or filter means 40 is secured to the flange 32 and extends peripherally around the second tubular section 24 to provide a relatively large filter means for the system 10. The filter element 40 permits passage of air into the chamber 36 to vent the drainage system, as described below, and filters the air passing into the chamber 36 to prevent contamination to the drainage system 10.
A section of flexible tube designated generally 42 is received in the body member 20, and has one end 44 secured to the downstream end 38 of the first tubular section 22 in the chamber 36. Although the downstream end 38 of the first tubular section 22 is shown as being received in the one tube end 44, it is understood that the one tube end 44 may be received in the drainage lumen 18c of the first tubular section and secured in place in the downstream section end 38. Also, the tube 42 may be removably secured to the first tubular section 22. The other free end 46 of the flexible tube 42 which extends downstream from the first tubular section 22 is received in the lumen 18d of the relatively rigid second tubular section 24, and the outside diameter of the free tube end 46 is approximately equal to the inside diameter of the second tube section 24. Accordingly, the tube 42 communicates between the drainage lumens 18c and 18d in the first and second tubular sections 22 and 24, respectively.
When a negative pressure develops in the drainage system 10, relative to the atmosphere, air passes through the filter elements 40 into the chamber 36, and the free end 46 of the tube 42 flexes sufficiently from the inside of the second tubular section 24 such that air from the chamber passes between the outside of the free tube end 46 and the inside of the second tubular section 24, and into the drainage lumen 18d to vent the system 10. The direction of air flow during venting is indicated by the arrows in the drawings. When a positive pressure, relative to the atmosphere, develops in the drainage system, such as caused by liquid refluxing from the drainage tube 16 into the adapter 14, the free tube end 46 is forced against and engages the inside of the second tubular section 24 to prevent the escape of drainage liquid from the lumen 18d of the drainage system into the chamber 36, since the outside diameter of the free tube end 46 is approximately equal to the inside diameter of the second tubular section 24. Accordingly, liquid draining in the system 10 is prevented from contacting the filter element 40 which might result in damage to the filter element and cause eventual contamination to the drainage system 10.
As noted previously, the flange 32 may be removably attached to the annular rim 30, and the one tube end 44 may be removably secured to the downstream end 38 of the first tubular section 22. When the flange 32 is removed from the rim 30 and the tube 42 is removed from the first tubular section 22, as shown in FIG. 4, the drainage tube 16 may be directly secured to the downstream end 38 of the first tubular section 22. Thus, the drainage system 10 may be readily modified to a non-vented configuration by attaching the drainage tube 16 to the adapter 14 in this manner.
A vented liquid drainage system is illustrated in FIG. 5 as another embodiment of the present invention. The drainage system designated generally 60 includes a drainage tube 62 having a lumen 64 for draining liquid. A vent 66 extends from the tube and communicates between the atmosphere and an opening 68 in the wall of the tube 62 to vent the tube lumen 64, and an air permeable filter 70 is positioned in the vent 66 to filter the air passing through the vent.
A section of flexible tube 72 is received in the drainage tube 62 and has an outside diameter approximately equal to the inside diameter of the drainage tube 62. The tube section 72 is positioned in the drainage tube 62 with the tube opening intermediate the ends of the tube section. In order to prevent the tube section from sliding in the drainage tube, one end 74 is secured to the inside of the drainage tube 62, as at 80, and the other free end 76 extends past the tube opening 68.
Thus, when a negative pressure develops in the tube lumen 64, relative to the atmosphere, the free end 76 of the tube section 72 flexes to permit passage of air from the vent 66 into the lumen 64. However, when a positive pressure, relative to the atmosphere develops in the lumen 64, such as caused by liquid refluxing in the tube 62, the free end 76 of the tube section 72 is forced against and engages the inside of the drainage tube 62 to prevent the escape of liquid from the lumen into the vent 66. Consequently, the filter 70 is protected against contact by the liquid, as described in connection with the adapter of FIGS. 1-4. Although the lumen 64 is shown as being vented through a single opening 68, it is readily apparent that the system 60 may be vented through a plurality of openings disposed circumferentially around the tube relative to the opening 68 by appropriate modification of the vent 66.
During drainage of the system 60, the fluid normally flows in a single direction. Although the tube section 72 is operable to vent the system and protect the filter from fluid normally flowing in either direction in the system, preferably the free tube end 76 extends downstream from the tube opening 68 relative to the normal direction of fluid flow. Accordingly, the preferred direction of normal fluid flow is directed from left to right as viewed in FIG. 5.
Another embodiment of the vented drainage system, which is similar to the system shown in FIG. 5, illustrated in FIG. 6. In this embodiment, the drainage tube has an enlarged annular portion 82 extending on both sides of the tube opening 68. The length of the enlarged portion 82 is slightly greater than the length of the tube section 72, and the outside diameter of the tube section 72 is approximately equal to the inside diameter of the enlarged portion 82, such that the tube section 72 may be received in the enlarged portion 82 of the drainage tube 62.
Since the drainage tube is more narrow at the ends of the enlarged portion 82, the tube section 72 is prevented from sliding from its position in the enlarged portion, and it is apparent that both ends 84a and 84b of the tube section 72 may be free to vent the system 60 at both ends. Also, both of the free ends 84a and b of the tube section 72 engage against the inside of the enlarged portion 82 to prevent passage of fluid from the lumen 64 into the vent. Accordingly, there is no preferred direction of normal fluid flow, as viewed in FIG. 6, since the system is equally operable for normal drainage flow in either direction. Preferably, the longitudinal center of the tube section 72 is located approximately adjacent to the tube opening 68 to provide paths of equal distance for air flowing past the ends 84a and b in venting the system 60.
The foregoing detailed description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.
1. Field of the Invention
This invention relates to vented liquid drainage systems.
2. Description of the Prior Art
It is known that in systems for the drainage of fluids from the body, such as indwelling catheters, a negative pressure may be created in such systems which has a deleterious effect on the body. To alleviate this result, Ericson U.S. Pat. No. 3,429,314 discloses a vented drainage system which prevents buildup of a negative pressure, and shows a filter unit positioned in the vent to prevent the passage of bacteria into the system. However, if fluids in the system contact the filter unit, it may be rendered inoperable, and Ericson U.S. Pat. No. 3,419,009 teaches the use of a valve to protect the filter. In an application filed June 2, 1971, Ser. No. 149,315, U.S. Pat. No. 3,730,209, entitled "Vent for Liquid Drainage System" we disclosed a vented adapter.
SUMMARY OF THE INVENTION
The principal feature of the present invention is a vented drainage system having tubular sections interfitting with each other to provide intimate interfacial contact sufficient to prevent the passage of liquid between the interfacial surfaces thereof, one of the sections being flexible and responsive to a pressure differential between the inside of the sections when filled with liquid and the atmosphere on the outside of the sections to cause the flexible tubular section to flex and to become disengaged from interfacial contact with the other section to provide a passageway for the passage of air therebetween. The passageway communicates with the atmosphere to relieve the pressure differential.
The invention will first be described embodied in a new and improved vented adapter of simplified construction for in-line use in a liquid drainage system.
The vented adapter of the present invention has a body member and a section of flexible tube received in the body member. The body member includes first and second tubular sections, each of which has a drainage lumen. The second tubular section is spaced from and positioned downstream from the first tubular section with their lumens being generally aligned. The flexible tube has one end secured to the downstream end of the first tubular section and the other free end received in the lumen of the second tubular section, and the outside diameter of the free tube end is approximately equal to the inside diameter of the second tubular section.
A feature of the present invention is that the tube communicates between the lumens in the first and second tubular sections.
Another feature of the invention is that the free tube end engages the inside of the second tubular section to prevent the escape of drainage liquid from the system.
A further feature of the invention is that the free tube end flexes to permit passage of air into the drainage lumen of the second tubular section.
The body member includes an annular rim extending outwardly and downstream from the first tubular section, and a flange extending radially outwardly from the second tubular section and attached to the rim, such that the rim and flange define a chamber containing the downstream end of the first tubular section and an upstream portion of the tube. An air permeable filter element is secured to the flange and extends peripherally around the second tubular section.
Another feature of the present invention is the provision of relatively large filter means to filter and pass air for venting the system.
A further feature of the invention is that the flange may be removably attached to the annular rim and the tube may be removably secured to the first tubular section, in order that the second tubular section may be removed from the adapter to secure a drainage tube in the liquid drainage system directly to the downstream end of the first tubular section.
Further features will become more fully apparent in the following description of the embodiments of this invention and from the appended claims.
DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a fragmentary perspective view of a liquid drainage system, including the vented adapter of the present invention;
FIG. 2 is a fragmentary elevational view, taken partially in section, of the liquid drainage system and adapter of FIG. 1;
FIG. 3 is a sectional view taken substantially as indicated along the line 3--3 of FIG. 2;
FIG. 4 is a sectional view of a portion of the adapter of FIG. 2 with a drainage tube in the liquid drainage system secured to the adapter in a non-vented configuration;
FIG. 5 is a fragmentary sectional view of another embodiment of the present invention; and
FIG. 6 is a fragmentary sectional view of another embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention relates generally to liquid drainage systems, such as systems for draining liquid from the body cavity of a patient, which are vented to the atmosphere to alleviate negative pressure which may develop in the systems. The invention will first be described embodied in a vented adapter for in-line use in a liquid drainage system.
Referring now to FIGS. 1 and 2, a liquid drainage system, generally designated 10, is shown including an interconnected catheter 12, an adapter designated generally 14, and a drainage tube 16. During use of the drainage system 10, the distal end of the catheter (not shown) is inserted into the body cavity of a patient, such as the bladder, and liquid drains through a lumen 18a in the catheter 12, as shown in FIG. 2, through the adapter 14, and through a lumen 18b in the drainage tube 16 to a receptacle (not shown) for collection.
The adapter 14 of the present invention has a relatively rigid body member, generally designated 20, which includes first and second spaced tubular sections 22 and 24, respectively. The first tubular section 22 has a longitudinally extending drainage lumen 18c and the upstream end 26 of the first tubular section 22 is received in the proximal end 28 of the catheter 12, such that the lumen 18c communicates with the lumen 18a in the catheter. The second tubular section 24 has a longitudinally extending drainage lumen 18d, and the tubular section 24 is received in the drainage tube 16 with the lumen 18d communicating with the lumen 18b in the drainage tube. The first and second tubular sections 22 and 24 are positioned in the body member 20 with their respective drainage lumens 18c and 18d being generally aligned with each other.
The body member 20 has an annular rim 30 which extends outwardly from the first tubular section 22 intermediate its ends and which extends downstream from the first tubular section. The body member 20 also has a flange 32 extending radially outwardly from the upstream end of the second tubular section 24, and which is secured to the rim 30, such as by gluing or heat sealing the flange 32 in an annular groove 34 in the rim 30. However, it is contemplated that the flange 32 may be removably attached to the rim 30, such as by snap-fitting the flange and rim together in sealing engagement. Also, the flange 32 and rim 30 may be integral with each, such that the rim may be secured to the first tubular section 22 adjacent the juncture of the rim and the first tubular section.
The rim 30 and flange 32 constitutes a housing defining a chamber 36 which contains the downstream end 38 of the first tubular section 22. As shown in FIGS. 2 and 3, an air permeable filter element or filter means 40 is secured to the flange 32 and extends peripherally around the second tubular section 24 to provide a relatively large filter means for the system 10. The filter element 40 permits passage of air into the chamber 36 to vent the drainage system, as described below, and filters the air passing into the chamber 36 to prevent contamination to the drainage system 10.
A section of flexible tube designated generally 42 is received in the body member 20, and has one end 44 secured to the downstream end 38 of the first tubular section 22 in the chamber 36. Although the downstream end 38 of the first tubular section 22 is shown as being received in the one tube end 44, it is understood that the one tube end 44 may be received in the drainage lumen 18c of the first tubular section and secured in place in the downstream section end 38. Also, the tube 42 may be removably secured to the first tubular section 22. The other free end 46 of the flexible tube 42 which extends downstream from the first tubular section 22 is received in the lumen 18d of the relatively rigid second tubular section 24, and the outside diameter of the free tube end 46 is approximately equal to the inside diameter of the second tube section 24. Accordingly, the tube 42 communicates between the drainage lumens 18c and 18d in the first and second tubular sections 22 and 24, respectively.
When a negative pressure develops in the drainage system 10, relative to the atmosphere, air passes through the filter elements 40 into the chamber 36, and the free end 46 of the tube 42 flexes sufficiently from the inside of the second tubular section 24 such that air from the chamber passes between the outside of the free tube end 46 and the inside of the second tubular section 24, and into the drainage lumen 18d to vent the system 10. The direction of air flow during venting is indicated by the arrows in the drawings. When a positive pressure, relative to the atmosphere, develops in the drainage system, such as caused by liquid refluxing from the drainage tube 16 into the adapter 14, the free tube end 46 is forced against and engages the inside of the second tubular section 24 to prevent the escape of drainage liquid from the lumen 18d of the drainage system into the chamber 36, since the outside diameter of the free tube end 46 is approximately equal to the inside diameter of the second tubular section 24. Accordingly, liquid draining in the system 10 is prevented from contacting the filter element 40 which might result in damage to the filter element and cause eventual contamination to the drainage system 10.
As noted previously, the flange 32 may be removably attached to the annular rim 30, and the one tube end 44 may be removably secured to the downstream end 38 of the first tubular section 22. When the flange 32 is removed from the rim 30 and the tube 42 is removed from the first tubular section 22, as shown in FIG. 4, the drainage tube 16 may be directly secured to the downstream end 38 of the first tubular section 22. Thus, the drainage system 10 may be readily modified to a non-vented configuration by attaching the drainage tube 16 to the adapter 14 in this manner.
A vented liquid drainage system is illustrated in FIG. 5 as another embodiment of the present invention. The drainage system designated generally 60 includes a drainage tube 62 having a lumen 64 for draining liquid. A vent 66 extends from the tube and communicates between the atmosphere and an opening 68 in the wall of the tube 62 to vent the tube lumen 64, and an air permeable filter 70 is positioned in the vent 66 to filter the air passing through the vent.
A section of flexible tube 72 is received in the drainage tube 62 and has an outside diameter approximately equal to the inside diameter of the drainage tube 62. The tube section 72 is positioned in the drainage tube 62 with the tube opening intermediate the ends of the tube section. In order to prevent the tube section from sliding in the drainage tube, one end 74 is secured to the inside of the drainage tube 62, as at 80, and the other free end 76 extends past the tube opening 68.
Thus, when a negative pressure develops in the tube lumen 64, relative to the atmosphere, the free end 76 of the tube section 72 flexes to permit passage of air from the vent 66 into the lumen 64. However, when a positive pressure, relative to the atmosphere develops in the lumen 64, such as caused by liquid refluxing in the tube 62, the free end 76 of the tube section 72 is forced against and engages the inside of the drainage tube 62 to prevent the escape of liquid from the lumen into the vent 66. Consequently, the filter 70 is protected against contact by the liquid, as described in connection with the adapter of FIGS. 1-4. Although the lumen 64 is shown as being vented through a single opening 68, it is readily apparent that the system 60 may be vented through a plurality of openings disposed circumferentially around the tube relative to the opening 68 by appropriate modification of the vent 66.
During drainage of the system 60, the fluid normally flows in a single direction. Although the tube section 72 is operable to vent the system and protect the filter from fluid normally flowing in either direction in the system, preferably the free tube end 76 extends downstream from the tube opening 68 relative to the normal direction of fluid flow. Accordingly, the preferred direction of normal fluid flow is directed from left to right as viewed in FIG. 5.
Another embodiment of the vented drainage system, which is similar to the system shown in FIG. 5, illustrated in FIG. 6. In this embodiment, the drainage tube has an enlarged annular portion 82 extending on both sides of the tube opening 68. The length of the enlarged portion 82 is slightly greater than the length of the tube section 72, and the outside diameter of the tube section 72 is approximately equal to the inside diameter of the enlarged portion 82, such that the tube section 72 may be received in the enlarged portion 82 of the drainage tube 62.
Since the drainage tube is more narrow at the ends of the enlarged portion 82, the tube section 72 is prevented from sliding from its position in the enlarged portion, and it is apparent that both ends 84a and 84b of the tube section 72 may be free to vent the system 60 at both ends. Also, both of the free ends 84a and b of the tube section 72 engage against the inside of the enlarged portion 82 to prevent passage of fluid from the lumen 64 into the vent. Accordingly, there is no preferred direction of normal fluid flow, as viewed in FIG. 6, since the system is equally operable for normal drainage flow in either direction. Preferably, the longitudinal center of the tube section 72 is located approximately adjacent to the tube opening 68 to provide paths of equal distance for air flowing past the ends 84a and b in venting the system 60.
The foregoing detailed description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.