WO1997046173A1

WO1997046173A1 - Backflow prevention system in suctioning apparatus

Info

Publication number: WO1997046173A1
Application number: PCT/US1997/009720
Authority: WO
Inventors: Kevin Helmer; Richard Bushman
Original assignee: Kevin Helmer; Richard Bushman
Priority date: 1996-06-03
Filing date: 1997-06-03
Publication date: 1997-12-11
Also published as: AU3230997A

Abstract

A dental apparatus backflow prevention system (10) substantially prevents contaminant backflow into a patient's mouth. The system includes a saliva ejector tube (5) for insertion into the patient's mouth, and for removal of saliva, blood, etc. when a vacuum is applied. A backflow prevention device (10) receives fluid from the saliva ejector tube (5) and includes an internal valve seat (55). Valve componential disposed within the backflow prevention device includes a housing (65) and a seating mechanism (70) operably supported by the housing (65) to automatically engage the valve seat (55), and prevent contaminant backflow upon release of the vacuum. Upon application of vacuum, however, the seating mechanism (70) automatically disengages from the valve seat (55) and allows fluid flow away from the patient's mouth. According to one embodiment, the seating mechanism (70) is functionally flexible for movement within the housing away from the valve seat (55), and is biased to move toward the valve seat (55) upon release of vacuum. A corresponding method provides similar advantages.

Description

BACKFLOW PREVENTION SYSTEM IN SUCTIONING APPARATUS

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to suctioning devices, and more particularly to medical suctioning devices that are adapted to prevent backflow of saliva, blood and other contaminants into the mouth of a dental patient, for example. Embodiments of the invention have potential application beyond the dental and medical arts, however. 2. Description of Related Art

It has been recognized in the art that cross-contamination between patients, for example, dental patients, can occur when suctioning devices attached to vacuum lines are used to remove various bodily and /or externally introduced fluids. Although the disposable distal ends of these devices typically are changed between patients, the vacuum lines employed typically are not changed. Saliva, blood and other contaminants pass from the distal end into the vacuum line, where they can remain until arrival of the next patient. When a new distal end is inserted onto the vacuum line for a new patient, contaminants from the previous patient can backflow from the vacuum line into the distal end and enter the patient's mouth, for example. Clearly, with the growing incidence of AIDS and other communicable diseases, this is a situation to be avoided.

A number of prior art devices have attempted to prevent backflow and the resulting likelihood of cross-contamination between patients. U.S. Patents Nos. 5,425,637 and 5,509,802 to Whitehouse et al. and 5,464,397 to Powers, Jr., which are incorporated herein by reference, disclosed prior art attempts to prevent or at least minimize contaminant backflow and cross- contamination. The two Whitehouse patents disclose suction lines having vacuum-release apertures through a tubular sidewall of a saliva ejector tip. If a patient closes his or her lips around the tip, the vacuum- release aperture is said to prevent creation of a temporary high vacuum in the patient's mouth; the aperture also likely prevents stoppage of air and /or fluid, at least between the aperture and the rest of the vacuum system. The Powers, Jr. patent, on the other hand, appears to rely merely on a "tortuous path" within the device to substantially prevent backflow of bacteria. However, as recent studies are believed to have shown, a boundary layer can form around the internal circumference of many currently used suctioning devices. The boundary layer is the portion of air and/or other fluid flowing in the immediate vicinity of the internal circumference. Flow within the boundary layer is severely reduced, even eliminated due to the forces of adhesion and viscosity caused by the internal circumference. Because suction within the boundary layer is reduced or eliminated, a "bio-film" can be created, allowing saliva, blood and other contaminants to flow by gravity, for example, from the main vacuum system of a dental office, through saliva ejector assemblies and into the mouths of patients.

It is not believed that prior art suctioning devices adequately account for or address backflow caused by boundary layer conditions, and /or other conditions such as mouth-induced backflow suction. Prior art devices thus allow an unacceptably high likelihood of cross- contamination between patients. Clearly, a need has arisen for a solution to this problem.

SUMMARY OF THE INVENTION To address the above and other problems, a dental apparatus backflow-prevention system substantially prevents contaminant backflow into a patient's mouth. The system includes a saliva ejector tube for insertion into the patient's mouth and for removal of saliva, blood, etc. when a vacuum is applied. A backflow-prevention device receives fluid from the saliva ejector tube and includes an internal valve seat. Valve componentry disposed within the backflow-prevention device includes a housing and a seating mechanism operably supported by the housing to automatically engage the valve seat and prevent contaminant backflow upon release of the vacuum. Upon application of vacuum, however, the seating mechanism automatically disengages from the valve seat and allows fluid flow away from the patient's mouth. According to one embodiment, the seating mechanism is functionally flexible for movement within the housing away from the valve seat, and is spring- biased to move toward the valve seat upon release of vacuum. A corresponding method provides similar advantages.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will be described with respect to the figures, in which like numerals denote like elements and in which:

Figure 1 is an isometric, exploded view of a backflow-prevention system according to an embodiment of the invention;

Figure 2 is a cross-sectional view of the Figure 1 system; Figure 3 is an isometric, exploded view of a backflow-prevention system according to an alternative embodiment of the invention; Figure 4 is a cross-sectional view of the Figure 3 system; Figure 5 is an isometric view of alternative valve componentry according to an embodiment of the invention; Figure 6 is a cross-sectional view of the Figure 5 componentry;

Figure 7 is an isometric view of alternative valve componentry according to an embodiment of the invention;

Figure 8 is a cross-sectional view of the Figure 7 componentry; Figure 9 is an isometric view of alternative valve componentry according to an embodiment of the invention;

Figure 10 is a cross-sectional view of the Figure 9 componentry; Figure 11 is an isometric view of valve componentry according to the embodiment of Figures 1-2; and

Figure 12 is an isometric view showing the embodiment of Figures 1-2 in assembled form. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Embodiments of the invention have wide application to a number of medical procedures and environments. Suction is often used in dental applications, as described above. Suctioning devices are also typically used to drain fluid and remove blood from many surgical environments, aid in respiration, and aid in a number of other medical and surgical procedures. Additionally, suctioning devices in which cross-contamination is undesirable also are used in non-medical and non-surgical environments. Therefore, although preferred embodiments of the invention will be described with respect to dental devices and applications, the invention is not limited to these embodiments.

As shown in e.g. Figures 1-2, a dental suctioning device according to the invention preferably includes saliva ejector tube 5 for insertion into a patient's mouth, backflow-prevention device 10 with corresponding distal portion 13, internal valve componentry 15, and main body cap or proximal portion 20, and vacuum source /apparatus 25. Together, saliva ejector tube 5 and backflow-prevention device 10, optionally further including vacuum source /apparatus 25, make up a backflow-prevention system according to an embodiment of the invention. Saliva ejector tube 5 includes distal end 30, which preferably serves as a mouthpiece for contacting and directly withdrawing saliva, blood and /or other fluids and contaminants from a patient's mouth during a dental procedure, for example. Saliva ejector tube 5 further includes proximal end 35, for connection to backflow-prevention device 10. Specifically, proximal end 35 of saliva ejector tube 5 is preferably received within substantially straight-walled orifice 40 of neck portion 45 in distal portion 13 of backflow-prevention device 10. Orifice 40 allows fluids to enter main body 50 of backflow-prevention device 10. According to the illustrated embodiment, orifice 40 includes a portion 43 of reduced circumference, to "bite" into and thus better secure ejector tube 5. Of course, other connection arrangements between tube 5 and connection device 10 are contemplated according to the invention. Backflow-prevention device 10 also includes blocking seat 55 comprising a central orifice, as shown. Blocking seat 55 preferably is directly connected to central cavity 60, which receives fluids from orifice 40 and which preferably is of a substantially tapered shape, as shown, to improve flow characteristics. Blocking seat 55 is disposed distally of substantially annular orifice 58, described below. According to one embodiment, seat 55 is of substantially thin-walled and/or flexible construction, to better conform to the shape of an engagement member of associated valve componentry, as will be described. Valve componentry 15 according to an embodiment of the invention will now be described with respect to Figures 1-2 and 11. Valve componentry 15 includes outer support ring or housing 65, which according to the illustrated embodiment is substantially circular but can take other shapes as may be desirable to match the internal or external shapes of distal and proximal portions 13, 20 of backflow-prevention device 10. Outer ring 65 supports seating mechanism or blocking member 70, which allows fluid flow of saliva and /or other substances when vacuum is applied via vacuum source 25, and substantially prevents backflow of such substances when vacuum is not applied by seating within seat 55.

Seating mechanism 70 includes engagement member 75, preferably of substantially ball-like or bulbous shape, and biassing member or spring assembly 80, best shown in Figure 11. According to the illustrated embodiment, spring assembly 80 comprises a substantially triangular base portion 210, supporting two outer legs 215 and a central leg 220. Legs 215, 220 each include notches 225, the placement of which can be chosen to affect the spring action of seating mechanism 70, i.e. the force necessary to open and /or close the orifice in seat 55. Although only one notch is disposed in each leg 215, 220 in the illustrated embodiments, it is contemplated that each leg could have a plurality of notches 225.

According to a preferred embodiment, spring assembly 80 is in a minimal-stress condition when engagement member 75 is engaged with - 6 -

seat 55. A minimal-stress condition is preferred over a zero-stress condition, to minimize the tendency of engagement member 75 to bounce or otherwise move in seat 55. Thus, in the absence of external forces, the orifice of seat 55 is closed and backflow is substantially prevented. After vacuum is turned on and reaches a certain pressure, however, legs 215, 220 bend such that engagement member 75 moves into an open position with respect to seat 55, allowing fluid to flow from the patient's mouth toward vacuum apparatus 25. As vacuum is shut off, seating mechanism snaps or otherwise moves to a closed position. Seating mechanism 70 thus is functionally flexible.

Of course, a variety of connection arrangements between seating mechanism 70 and the inside surface of outer ring 65 are contemplated. For example, engagement member 75 can be connected to outer ring 65 by a plurality of circumferentially spaced spring assemblies 80 to allow e.g. substantially linear movement of seating engagement member 75 into and out of engagement with blocking seat 55 of backflow-prevention device 10. Engagement member 75 also can include a substantially cup-shaped or other surface for close interface with housing 65, such that any backflow helps move seating mechanism 70 to its closed position. Returning primarily to Figures 1-2, main body cap 20 preferably includes annular flange 85 for connection to the rest of backflow- prevention device 10, for example by snap-fitting into snap-ring 90 thereof. Because the distal and proximal portions 13, 20 of backflow-prevention device 10 are constructed to snap-fit together, it may be beneficial in certain situations (e.g. production environments) for valve componentry 15 to be readily removably disposed within backflow-prevention device 10 for easy replacement, if needed. In most applications, however, backflow- prevention device 10 is intended to be disposable in its entirety and therefore replacement of componentry likely will not be needed. Valve componentry 15 is accommodated within annular orifice 58 of distal portion 13 preferably by a friction fit, with substantially triangular members 93 "biting" into housing 65 of componentry 15 as it is inserted into recess 58. Proximal portion 20 includes similar members for better engaging snap-ring 90, and for additionally compressing valve componentry 15.

It should also be noted that seat 55 extends a sufficient distance above the distal walls 92 of orifice 58 to create a "damming" effect for reducing backflow past seat 55. Before backflow can reach seat 55, it must build up within well 94 surrounding seat 55 and reach a "height" sufficient to flow through the orifice in seat 55. This creates a time delay, giving seating mechanism 70 time to close before backflow can occur. Main body cap 20 also preferably includes substantially straight- walled cavity 95 and substantially tapered portion 100, which leads to neck portion 105. Neck portion 105 includes orifice 110 for connection to receptacle portion 115 of vacuum apparatus 25. Fluids pass through orifice 110 into receptacle portion 115 for removal, and are prevented from flowing back toward saliva ejector tube 5 by valve componentry 15 and associated housing. Vacuum apparatus 25 also preferably includes an on/off valve to activate /deactivate vacuum pressure.

Figure 12 shows the system of Figures 1-2 in an assembled condition. Figures 3-4 illustrate an alternative embodiment of the invention.

According to this embodiment, saliva ejector tube 5 is substantially similar to that described in the previous embodiment. Backflow-prevention device 10, however, includes a plurality of internal fins 130, which lead to blocking seat 55. Although six fins 130 are used according to the illustrated embodiment, a greater or lesser number can be used as desired.

Valve componentry 15 according to this embodiment includes preferably spherical ball 140, urged toward blocking seat 55 by wound spring 145. When vacuum is not applied, ball 140 is substantially sealingly engaged with seat 55, and componentry 15 thus prevents backflow into saliva ejector tube 5. When vacuum is applied, on the other hand, ball 140 compresses spring 145 against seat 150 of main body cap 20, allowing fluid to flow from saliva ejector tube 5 through backflow-prevention device 10 and into vacuum apparatus 25.

Main body cap 20 according to the embodiment of Figures 3-4 also includes a plurality of fins 155 preferably corresponding to fins 130 of the rest of backflow-prevention device 10. Together fins 130, 155 control movement of valve componentry 15 and allow flow of fluid around componentry 15 through main body portion 20 when vacuum is applied. Fins 130, 155 also substantially prevent relative rotation between backflow- prevention device 10 and main body cap 20. As illustrated, main body cap 20 also preferably includes annular flange 160 for entering orifice 170 of backflow-prevention device 10 and snap-fitting into corresponding annular recess 175 therein. Other elements of the embodiment illustrated in Figures 3-4 are similar to those described with respect to Figures 1-2 and will not be described again, to simplify the disclosure.

Valve componentry 15 can take various alternative forms, as shown in Figures 5-8. Conical device 185, for example, can be used in connection with resilient material 190 to maintain pressure on blocking seat 55 in the absence of vacuum and thus prevent backflow. Alternatively, flap device 195 with at least one seating flange 198 can be used, as can blocking portion 200 with spring-actuating portions 205.

Preferably, valve componentry 15 is of very light weight to ensure a wide enough opening at blocking seat 55 when vacuum is applied. Valve componentry 15 allows the orifice within blocking seat 55 to be relatively large, greatly reducing the likelihood of clogging. Further, saliva ejector tube 5 and backflow-prevention device 10 are preferably disposable according to an embodiment of the invention.

An air-flow indicator, e.g. a molded arrow, can be used to indicate airflow direction. The indicator can be disposed on the outside of neck portion 45 of backflow-prevention device 10, for example, or at any other desired portion of the system. Additionally, a moisture-detection indicator can be included in backflow-prevention device 10 to indicate when moisture passes through it. For example, backflow-prevention device 10 can be formed of or can include a color-change material so that internal moisture is indicated by an external color change.

The various elements of the invention can be formed of multiple molded plastic parts. As alternatives to plastic, other moldable or even non-moldable materials demonstrating sufficient rigidity, for example polypropylene, polyethylene, various thermal elastomers, and other engineering polymers /plastics, can be used. Spring steel can be used, for example to construct base 210 and /or legs 215, 220 of spring assembly 80. According to one embodiment, the material can be impregnated with a germicide or other anti-bacterial substance, to further reduce the dangers associated with cross-contamination. The various components can be of either permanent or disposable construction.

While the invention has been described with reference to specific embodiments, the description is illustrative and is not to be construed to be limiting the scope of the invention. For example, features of the various described embodiments can be mixed and matched to suit a particular application. As one example, spring 145 in the embodiment of Figures 3-4 can be used in place of resilient element 195 in the embodiment of Figures 5-6, and vice versa. Componentry 15 in its various described forms is basically interchangeable between the various embodiments. Further, according to the invention, backflow of fluid contaminants can be prevented in a wide variety of dental, medical and other environments. Still further, although elements of the invention are illustrated as separate parts, one or more of the illustrated elements can be made as one-piece with each other, to reduce manufacturing costs and ease assembly, for example. Still further, embodiments of the invention are not limited to situations involving boundary-layer backflow, discussed above. Embodiments of the invention substantially eliminate backflow and the resulting cross-contamination in the vacuum line in a wide variety circumstances and applications. Various other modifications and changes may occur to those skilled in the art without departing from the spirit and scope of the invention.

Claims

WHAT IS CLAIMED: 1. A dental apparatus backflow prevention system for substantially preventing contaminant backflow into a patient's mouth, the system comprising: a saliva ejector tube for insertion into a patient's mouth and removal of fluid therefrom upon application of a vacuum; a backflow prevention device operably connected to the saliva ejector tube to receive the fluid therefrom, the backflow prevention device comprising: a distal portion having an internal valve seat; and a proximal portion coupled with the distal portion and constructed for operative connection to a vacuum source; and valve componentry disposed within the backflow prevention device, the valve componentry comprising: a housing; and a seating mechanism operably supported by the housing to automatically engage the valve seat and prevent contaminant backflow upon release of vacuum, and to automatically disengage from the valve seat and allow fluid flow toward the vacuum source upon application of the vacuum.

2. The system of claim 1, wherein the seating mechanism is functionally flexible for moving within the housing away from the valve seat upon application of vacuum, and for moving toward and into engagement with the valve seat upon release of vacuum.

3. The system of claim 1, wherein the seating mechanism comprises a bulbous engagement member for sealing contact with the valve seat.

4. The system of claim 1, wherein the seating mechanism comprises a biassing member for urging the seating mechanism toward and into contact with the valve seat upon release of vacuum.

5. The system of claim 4, wherein the biassing member comprises a plurality of legs, each leg including at least one notch.

6. The system of claim 1, wherein the housing of the valve componentry is substantially circular; further wherein the seating mechanism is supported on an inside surface of the housing.

7. The system of claim 1, wherein the distal and proximal portions of the backflow prevention device are constructed to snap-fit together.

8. The system of claim 1, wherein the distal and proximal portions of the backflow prevention device are constructed for ready attachment to and detachment from one another, further wherein the valve componentry is disposed within the distal and proximal portions of the backflow prevention by a friction fit.

9. The system of claim 1, wherein the distal portion of the backflow prevention device defines a substantially straight-walled orifice and a substantially tapered central cavity disposed distal to the valve seat for promoting fluid flow toward the vacuum source.

10. The system of claim 1, wherein the valve seat is substantially flexible to better at least partially conform to the shape of the seating mechanism.

11. The system of claim 1, wherein the proximal portion of the backflow prevention device comprises a main body cap, the main body cap defining substantially straight-walled and substantially tapered orifices for promoting fluid flow toward the vacuum source.

12. A system for removing fluids from a fluid source, the system comprising: a first member for directly receiving and for removing fluids from a fluid source by suction through the first member; and a second member for receiving fluids from the first member by suction through the second member, the second member comprising an internal orifice through which fluids flow away from the fluid source, the second member substantially preventing backflow of fluids toward the fluid source; the second member comprising a blocking member, wherein the absence of suction causes the blocking member to block the orifice to substantially prevent backflow of fluids toward the fluid source, further wherein the presence of suction causes the blocking member to open the orifice to allow flow of fluids away from the fluid source.

13. The system of claim 12, wherein the blocking member comprises a spring assembly for biassing the blocking member toward and into sealing contact with the internal orifice.

14. The system of claim 13, wherein the spring assembly comprises at least one notched leg.

15. The system of claim 12, wherein the presence of suction causes the blocking member substantially to move out of engagement with the internal orifice.

16. The system of claim 15, wherein the second member is formed in at least two portions that are snap-fit together.

17. A system for removing fluids from a fluid source, the system comprising: first means for directly receiving and for removing fluids from a fluid source by suction through the first member; and second means for receiving fluids from the first means by suction through the second means, the second means comprising orifice means for allowing flow of fluids away from the fluid source, the second means substantially preventing backflow of fluids toward the fluid source; the second means comprising blocking means for blocking the internal orifice means, wherein the absence of suction causes the blocking means to block the orifice means to substantially prevent backflow of fluids toward the fluid source, further wherein the presence of suction causes the blocking means to open the orifice means to allow flow of fluids away from the fluid source.

18. A method of substantially preventing contaminant backflow into a patient's mouth through a saliva ejector tube inserted into the patient's mouth, the method comprising: removing fluid from the patient's mouth through the saliva ejector tube upon application of a vacuum by a vacuum source; allowing fluid flow toward the vacuum source by automatically disengaging a seating mechanism of a backflow prevention device from a valve seat of the backflow prevention device, the backflow prevention device having proximal and distal ends and being operably coupled with the saliva ejector tube; and automatically engaging the seating mechanism with the valve seat and preventing contaminant backflow upon release of vacuum.