Abstract:
An fluid connector apparatus having an exhalation insert that provides an improved exhalation feature whereby ex -haled breathing gas flows out of the fluid connector apparatus in the form of elongated blades of gas. The elongated blades of gas enable improved fluid flow when compared with conventional circular jets of gas and advantageously also entrain atmospheric gases adjacent the gas blades to facilitate diffusion and dissipation of the gas blades. The fluid connector apparatus includes one or more elongated flow channels formed between the exhalation insert and the fluid connector. The exhaust gas flows through the flow channels, and the flow channels cause the discharged gas to be output in the form of the elongated blades of gas. The exhalation feature enables the outputting of exhaled breathing gas in greater volumes, at reduced velocities, and with reduced acoustic signature.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application claims the priority benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/917,611 filed on Dec. 18, 2013, the contents of which are herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The disclosed and claimed concept relates generally to devices that provide respiratory therapy to a patient and, more particularly, to an exhalation valve of a fluid connector that connects together a source of breathing gas and a patient interface in order to provide respiratory therapy to a patient. 
         [0004]    2. Description of the Related Art 
         [0005]    Obstructive sleep apnea (OSA) is a condition that affects millions of people from around the world. OSA is characterized by disturbances or cessation in breathing during sleep. OSA episodes result from partial or complete blockage of airflow during sleep that lasts at least 10 seconds and often as long as 1 to 2 minutes. In a given night, people with moderate to severe apnea may experience complete or partial breathing disruptions as high as 200-500 times per night. Because their sleep is constantly disrupted, they are deprived of the restorative sleep necessary for efficient functioning of body and mind. This sleep disorder has also been linked with hypertension, depression, stroke, cardiac arrhythmias, myocardial infarction and other cardiovascular disorders. OSA also causes excessive tiredness. 
         [0006]    Non-invasive respiratory therapies such as ventilation and pressure support therapies involve the placement of a patient interface device, which is typically a nasal or nasal/oral mask, on the face of a patient to interface a source of breathing gas such as a ventilator or pressure support system in fluid communication with the airway of the patient so that a flow of breathing gas can be delivered from the pressure/flow generating device to the airway of the patient. 
         [0007]    Typically, patient interface devices include a mask shell or frame having a cushion attached to the shell that contacts the skin of the patient. The mask shell and cushion are held in place by a headgear that wraps around the head of the patient. The mask and headgear form the patient interface assembly. A typical headgear includes flexible, adjustable straps that extend from the mask to attach the mask to the patient. 
         [0008]    There are numerous situations where it is necessary or desirable to deliver a flow of breathable gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube in their esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation. It is also known to deliver continuous positive airway pressure (CPAP) or variable airway pressure, which varies with the patient&#39;s respiratory cycle, to treat a medical disorder such as sleep apnea syndrome, in particular, obstructive sleep apnea (OSA), or congestive heart failure. 
         [0009]    A fluid connector such as an entrainment elbow is typically mounted to the patient interface device and is connectable with a flexible hose that extends to the source of breathing gas. Fluid connectors such as the aforementioned entrainment elbow are typically highly complex and require three or more directions of draw during an injection molding process and may further include other components that may be separately molded and then ultrasonically welded or otherwise attached to the elbow to form the fluid connector. 
         [0010]    Such fluid connectors typically include an atmospheric opening that can be covered by a silicone flapper that enables the patient to breath air from the atmosphere in the event that the source of breathing gas should fail for some reason. Such fluid connectors typically additionally include some type of exhalation feature that permits exhaled air to be discharged from the elbow in order to permit flushing of the fluid passage that extends generally between the source of breathing gas and the patient&#39;s airways. Such an exhalation feature has typically been in the form of a number of small holes formed in the fluid connector that permit exhaled air to be exhausted therethrough. While a greater number of relatively smaller holes can result in quieter exhaust flow, it has been known that the extent to which such holes can be reduced in size is limited due to shortcomings in manufacturing reliability. It thus would be desirable to provide an improved exhalation feature. 
       SUMMARY OF THE INVENTION 
       [0011]    An improved fluid connector apparatus having an improved exhalation insert provides an improved exhalation feature whereby exhaled breathing gas flows out of the fluid connector apparatus in the form of elongated blades of gas. The elongated blades of gas enable improved fluid flow when compared with conventional circular jets of gas and advantageously also entrain atmospheric gases adjacent the gas blades to facilitate diffusion and dissipation of the gas blades. The fluid connector apparatus includes one or more elongated flow channels that are formed between the exhalation insert and the fluid connector. The exhaust gas flows through the flow channels, and the flow channels cause the discharged gas to be output in the form of the elongated blades of gas. The exhalation feature thus enables the outputting of exhaled breathing gas in greater volumes, at reduced velocities, and with reduced acoustic signature, all of which are desirable. 
         [0012]    Accordingly, an aspect of the disclosed and claimed concept is to provide an improved exhalation insert that is cooperable with a fluid connector and that provides an exhalation feature whereby exhaust gases flow through elongated flow channels formed between the exhalation insert and the fluid connector in order to cause the gas that is output to be discharged in the form of elongated blades of gas which provide improved performance. 
         [0013]    Another aspect of the disclosed and claimed concept is to provide an improved fluid connector apparatus that employs the aforementioned improved exhalation insert. 
         [0014]    A further aspect of the disclosed and claimed concept is to provide an improved respiratory therapy apparatus that employs the aforementioned improved fluid connector apparatus. 
         [0015]    As such, an aspect of the disclosed and claimed concept is to provide an improved exhalation insert that is structured to be at least partially received in a receptacle that is formed in a fluid connector and that is in communication with an interior region of the fluid connector, the fluid connector being structured to connect together a patient interface device and a source of breathing gas which are structured to provide respiratory therapy to a patient. The exhalation insert can be generally stated as including a support that can be generally stated as including a peripheral wall that includes a peripheral surface, a mounting apparatus that can be generally stated as including at least a first abutment situated on the peripheral wall and protruding outwardly away from the peripheral surface, the at least first abutment having at least a first edge surface that extends from the peripheral surface and an engagement surface that extends from the at least first edge surface, at least a portion of the support and at least a portion of the mounting apparatus being structured to be received in the receptacle formed in the fluid connector, the engagement surface being structured to be engaged with a portion of a lateral surface of the fluid connector that is situated adjacent the receptacle, and the at least first edge surface and at least a portion of the peripheral surface that extends from the at least first edge surface together being structured to be cooperable with a confronting portion of the lateral surface to form at least a portion of a flow channel that is disposed between a portion of the support and a portion of the fluid connector and that is structured to enable fluid communication between the interior of the fluid connector and the atmosphere. 
         [0016]    These and other objects, features, and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective view of an improved fluid connector apparatus in accordance with a first embodiment of the disclosed and claimed concept; 
           [0018]      FIG. 2  is a schematic depiction of an improved respiratory therapy apparatus that employs the fluid connector apparatus of  FIG. 1 ; 
           [0019]      FIG. 3  is an exploded view of the fluid connector apparatus of  FIG. 1 ; 
           [0020]      FIG. 4  is another exploded view of the fluid connector apparatus of  FIG. 1 ; 
           [0021]      FIG. 5  is a top view of the fluid connector apparatus of  FIG. 1 ; 
           [0022]      FIG. 6  is an enlarged depiction of the enclosed portion of  FIG. 5 ; 
           [0023]      FIG. 7  is sectional view as taken along line  7 - 7  of  FIG. 1 ; 
           [0024]      FIG. 8  is a sectional view as taken along line  8 - 8  of  FIG. 1 ; 
           [0025]      FIG. 9  is an exploded and partially sectioned depiction of the fluid connector apparatus of  FIG. 1 ; 
           [0026]      FIG. 10  is a side elevational view of the exhalation insert; 
           [0027]      FIG. 11  is a schematic depiction of an exhaust gas blade that is discharged from the fluid connector apparatus and additionally depicts several alternative profiles that an exterior surface of the exhalation insert can take to provide different dissipation characteristics; 
           [0028]      FIG. 12  is a perspective view of an improved exhalation insert in accordance with a second embodiment of the disclosed and claimed concept; and 
           [0029]      FIG. 13  is a sectional view as taken along line  13 - 13  of  FIG. 12 . 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0030]    As used herein, the singular form of “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. As used herein, the statement that two or more parts or components are “coupled” shall mean that the parts are joined or operate together either directly or indirectly, i.e., through one or more intermediate parts or components, so long as a link occurs. As used herein, “directly coupled” means that two elements are directly in contact with each other. As used herein, “fixedly coupled” or “fixed” means that two components are coupled so as to move as one while maintaining a constant orientation relative to each other. 
         [0031]    Directional phrases used herein, such as, for example and without limitation, top, bottom, left, right, upper, lower, front, back, and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein. 
         [0032]    An improved fluid connector apparatus  4  in accordance with a first embodiment of the disclosed and claimed concept is depicted generally in  FIGS. 1-11 . Fluid connector apparatus  4  is advantageously employable in an improved respiratory therapy apparatus  6  that is depicted in  FIG. 2  as providing respiratory therapy to a patient  10 . Respiratory therapy apparatus  6  of  FIG. 2  can be said to include a schematically depicted interface device  12  which may be, by way of example, a nasal or nasal/oral mask or other such device that is suited to patient  10 . Fluid connector apparatus  4  places interface device  12  in fluid communication with a source of breathing gas  16  such as a CPAP machine or other such source of breathing gas. A supply hose  18  typically extends between source of breathing gas  16  and fluid connector apparatus  4 . 
         [0033]    As can be understood from  FIGS. 3 and 4 , fluid connector apparatus  4  can be said to include a fluid connector  22  and an improved exhalation insert  26  in accordance with an aspect of the disclosed and claimed concept. Fluid connector apparatus  4  additionally includes a flapper  28  that is depicted generally in  FIGS. 7 and 9  and which is a flexible valve-like element that will be described in greater detail below. 
         [0034]    Fluid connector  22  can be said to include a body  32  that is hollow and that has an interior region  38  formed therein. Fluid connector  22  can further be said to include a swivel component  34  that is pivotably situated on a supply leg  40  of body  32  and that is connectable with an end of supply hose  18 . Body  32  further includes an interface leg  44  opposite supply leg  40 . 
         [0035]    Body  32  has formed therein a receptacle  46  that is of a generally elliptical or other arcuate shape and that is in communication with interior region  38 . Body  32  further includes a lateral surface  50  that is adjacent receptacle  46 . Body  32  can further be said to have an atmospheric opening  52  formed therein that is in communication with the atmosphere and which enables air from the atmosphere to be drawn into interior region  38  as a result of normal breathing of patient  10  in the event of a failure of source of breathing gas  16 . In this regard, atmospheric opening  52  provides fluid communication between interior region  38  and the atmosphere, with such fluid communication being regulated by flapper  28 . More particularly, when a fluid pressure that is in excess of atmospheric pressure is experienced within interior region  38 , such as when source of breathing gas  16  provides a flow of breathing gas to patient  10 , such increased fluid pressure causes flapper  28  to deflect and cover atmospheric opening  52 , thereby enabling the flow of breathing gas to be therapeutically provided to patient  10  rather than flowing directly out of atmospheric opening  52 . 
         [0036]    It can be seen that receptacle  46  and atmospheric opening  52  are generally aligned with one another or at least partially overlie one another. This is advantageous because it permits a single draw during injection molding to form both receptacle  46  and atmospheric opening  52 , which advantageously reduces cost. 
         [0037]    Supply and interface legs  40  and  44  give to body  32  a generally elbow-like shape. Interface leg  44  has one or more lugs  56  situated thereon that enable a pivotable connection of fluid connector apparatus  4  with interface device  12 . 
         [0038]    Exhalation insert  26  can be said to include a support  58  and a mounting apparatus  62  that is situated on support  58 . Support  58 , in the depicted exemplary embodiment, can be said to include a central structure  64  having an exterior surface  68  and as further including a peripheral wall  70  having a peripheral surface  74 . In the depicted exemplary embodiment, central structure  64  is formed with an indentation  72  to which a brace  84  of support  58  is mounted. Exterior surface  68  is depicted herein as being generally flat and slightly curved, as can be understood best from  FIG. 10 . Exterior surface  68  faces in a direction generally away from fluid connector  22  when exhalation insert  26  is mounted thereon. Peripheral surface  74  is of a generally elliptical or otherwise arcuate shape. 
         [0039]    Mounting apparatus  62  can be said to include a plurality of abutments  76 A,  76 B,  76 C, and  76 D, which may be collectively or individually referred to herein with the numeral  76 . Abutments  76  are situated on peripheral wall  70  and protrude outwardly from peripheral surface  74 . Abutments  76  each include an engagement surface  78 A,  78 B,  78 C, and  78 D which may be collectively or individually referred to herein with the numeral  78 . Engagement surfaces  78  are radially outwardly offset outwardly from peripheral surface  74  and each face in a direction generally away from peripheral wall  70 . In the depicted exemplary embodiment, engagement surfaces  78  are likewise of a generally partially elliptical or otherwise arcuate shape. Abutments  76  each include a pair of abutment edges that are in the form of surfaces that are indicated generally at the numeral  80  herein for purposes of simplicity of disclosure. Abutment edges  80  can be said to extend generally between peripheral surface  74  and engagement surfaces  78 . 
         [0040]    Support  58  can further be said to include the aforementioned brace  84 , and to further include a retention apparatus  82  that is situated on peripheral wall  70  at a location generally opposite exterior surface  68 . Retention apparatus  82  includes a latch  86  that is formed on brace  84  and another latch  88  situated generally on abutment  76 A opposite latch  86 . Latches  86  and  88  are engagable with an interior surface of body  32 , as is depicted generally in  FIG. 7 . 
         [0041]    Brace  84  can be seen in  FIG. 7  to protrude generally into interior region  38  and to engage flapper  28  or to be engageable therewith to resist flapper  28  from undesirably deflecting into the interior of supply leg  40 . Flapper  28  is depicted in  FIG. 9  as being in its free state, and it is therefore understood that flapper  28  is depicted in  FIG. 7  as being at least partially deflected toward atmospheric opening  52  via its engagement with brace  84 .  FIG. 7  also depicts in dashed lines the position of flapper  28  overlying atmospheric opening  52 , such as when a pressure in excess of atmospheric pressure is experienced within interior region  38 . 
         [0042]    In accordance with certain aspects of the disclosed and claimed concept, fluid connector apparatus  4  further includes a flow apparatus that can be said to include a plurality of flow channels  90 A,  90 B,  90 C, and  90 D, which may be collectively or individually referred to herein with the numeral  90 . Flow channels  90  are formed between exhalation insert  26  and fluid connector  22  when the two are connected together, and flow channels  90  can each be said to extend generally between portions of peripheral and lateral surfaces  74  and  50  that confront one another and that extend between an adjacent pair of abutments  76 . As such, flow channel  90 A can be said to be bounded by abutment edges  80  of abutments  76 A and  76 B at the ends thereof and to be further bounded by a portion of peripheral surface  74  that extends between abutments  76 A and  76 B and a confronting portion of lateral surface  50  that confronts the aforementioned portion of peripheral surface  74  that extends between abutments  76 A and  76 B. In a like fashion, flow channel  90 B can be said to extend between abutments  76 B and  76 C, flow channel  90 C can be said to extend between abutments  76 C and  76 D, and flow channel  90 D can be said to extend between abutments  76 D and  76 A, each of which additionally extends between a portion of peripheral surface  74  and a confronting portion of lateral surface  50  that extend between such adjacent pairs of abutments  76 . 
         [0043]    Exhalation insert  26  is mountable to fluid connector  22  to form fluid connector apparatus  4  by receiving brace  84  and retention apparatus  82  into receptacle  86  and receiving engagement surfaces  78  against lateral surface  50 . This causes latches  86  and  88  to snap fit and to engage an interior surface of body  32  to retain engagement surfaces  78  against lateral surface  50 . The engagement of engagement surfaces  78  with corresponding portions of lateral surface  50  retains exhalation insert  26  within receptacle  46  in the position depicted generally in  FIG. 5  whereby flow channels  90  are each unblocked, i.e., open, and permit exhaust gas to flow therethrough from interior region  38  toward the atmosphere at the exterior of fluid connector apparatus  4 . Since flow channels  90  are each of an elongated and narrow shape, such shape causes the gas that is exhausted therethrough to be exhausted in the form of a set of exhaust gas blades that are depicted in a schematic fashion in  FIGS. 1 and 11  at the numeral  92 . 
         [0044]    More particularly,  FIG. 11  depicts exhaust gas blade  92  discharging into the atmosphere and as entraining an entrained portion  94  of the atmosphere in a region adjacent exhaust gas blade  92 . That is, the flow of exhaust gas blades  92  into the atmosphere immediately outside of flow channels  90  causes the air surrounding exhaust gas blades  92  to be entrained with exhaust gas blades  92  due at least in part to the viscous and/or momentum properties of exhaust gas blade  92 . Such entrainment of exhaust gas blade  92  with the atmosphere causes exhaust gas blade  92  to be relatively quickly dissipated, thereby resulting in a reduced acoustic signature and a reduced pressure or jetting signature. Additionally, the entrainment of exhaust gas blades  92  with entrained portions  94  of the atmosphere causes enhanced dissipation and diffusion of exhaust gas blades  92  into the atmosphere to provide reduced jetting properties at the exterior of fluid connector apparatus  4 . This advantageously reduces the jetting effect on, for example, a bed partner. 
         [0045]    Moreover, while in the depicted exemplary embodiment the space between the portions of lateral surface  50  and peripheral surface  74  that bound flow channels  90  is only on the order of 0.010 inches (0.25 millimeters) in size, it is noted that the size and shape of exhalation insert  26 , as well as the distance between lateral surface  50  and peripheral surface  54  and the configuration of mounting apparatus  62 , individually or in combination, can be altered to suit the needs of any particular application. Such alteration can be tailored to provide whatever flow capability is required depending upon the pressures at opposite ends of flow channels  90 , the needed flow rates of exhaust gas, and other factors. As such, fluid connector apparatus  4  can be configured to provide flow channels  90  having any of a wide variety of desired flow properties. 
         [0046]    As can be understood from  FIG. 10 , engagement surfaces  78  are oriented oblique to one another and can be generally said to lie along the surface of an elliptical or non-elliptical cone  100 . In the depicted exemplary embodiment, engagement surfaces  78  are oriented at approximately 5° (five degrees) in opposite directions away from a reference which, in the depicted exemplary embodiment, is represented by an insertion direction  102 , which is the direction in which exhalation insert  26  is moved when being received into receptacle  46 . It is understood that lateral surface  50  and peripheral surface  74  are likewise oriented at the same angle with respect to the same reference. The conic arrangement of engagement surfaces  78  and lateral surface  50  in combination with latches  86  and  88  securely retains exhalation insert  26  on fluid connector  22  in the orientation depicted generally in  FIG. 5 . This advantageously and reliably retains flow channels  90  in an open condition and maintains their intended and desired flow properties. 
         [0047]    The flow of exhaust gas through flow channels  90  is depicted generally in  FIG. 11  as beginning at a leading edge of peripheral wall  70  and as being discharged into the atmosphere at a trailing edge  98  of peripheral wall  70 . In this regard, it is understood that leading edge  96  is situated generally adjacent or within interior region  38  whereas trailing edge  98  is situated adjacent or in the atmosphere. In this regard, therefore, it can be seen that various other modifications to the shapes, features, proportions, etc., of flow channels  90  themselves can be implemented to achieve desired entrainment and dissipation objective. The entrainment of entrained portions  94  of the atmosphere with exhaust gas blades  92  advantageously provides reduced pressure and acoustic signatures. Fluid connector apparatus  4  thus advantageously provides reliable flow channels  90  through which the exhaust gases are permitted to flow from interior region  38  to the atmosphere. 
         [0048]    It is understood that such entrainment of entrained portions  94  of the atmosphere is at least in part affected by the shape of exterior surface  68 .  FIG. 11  additionally depicts a plurality of exemplary alternative exterior surfaces  168 ,  268 , and  368  of alternate embodiments of exhalation insert  26  which can differently affect the entrainment of the atmosphere with exhaust gas blades  92 . It thus can be understood that the exemplary profile of exterior surface  68  that is provided herein is merely for purposes of illustration, and it is therefore expressly noted that exhalation insert  26  could have any of exterior surfaces  168 ,  268 ,  368 , or any combination thereof, or any other shape, depending upon the needs of the application. 
         [0049]    An improved exhalation insert  426  in accordance with a second embodiment of the disclosed and claimed concept is depicted generally in  FIGS. 12 and 13 . Exhalation insert  426  can be employed in place of exhalation insert  26  on fluid connector  22  to provide another improved connector apparatus in accordance with the disclosed and claimed concept. Exhalation insert  426  is similar to exhalation insert  26  except that it does not include mounting apparatus  62  or the resultant flow channels  90 . 
         [0050]    As can be seen in  FIGS. 12 and 13 , exhalation insert  426  includes a support  458  having a central structure  464  that has an interior surface  466  and an exterior surface  468 . Central structure  464  includes a plurality of plate elements  472  that are positioned side-by-side in a terraced fashion to cause the various plate elements  472  to each be slightly offset from one another in a direction parallel with a thickness  469  of central structure  464 . 
         [0051]    Plate elements  472  are advantageously arranged to each have the same thickness  469  and to have one or more flow holes  490  formed therein that permit the flow of exhaust gas therethrough into communication with the atmosphere. Since each plate element  472  has the same thickness  469 , flow holes  490  are each of substantially the same size and shape, and this facilitates the design and manufacture of tooling that forms exhalation insert  426  and flow holes  490 . Flow holes  490  are depicted herein as being in the exemplary shape of a nozzle having a relatively wider cross section adjacent interior surface  466  and having a relatively narrower cross section adjacent exterior surface  468 . 
         [0052]    Exhalation insert  426  includes a peripheral wall  470  having a peripheral surface  474  that is configured to be received in receptacle  46  in substantially the same fashion as exhalation insert  426 . It is noted, however, that the provision of flow holes  490  provides another mechanism by which exhaust gases can be permitted to flow to the atmosphere. 
         [0053]    It is also expressly noted that the concepts of exhalation insert  426  can be applied to or combined with exhalation insert  26 , such as by forming flow holes  490  in central structure  64  in addition to providing flow channels  90 . Such a combined arrangement can provide even further flow rates and enhanced dissipation with further reduced acoustic and pressure signals, depending upon the needs of the particular application. Other variations will be apparent. 
         [0054]    It is contemplated that any of the embodiments, combination of embodiments, or modification of embodiments of the disclosed concept described herein can be used by, for example and without limitation, a caregiver or technician, in the process of selecting a patient interface device for a patient. 
         [0055]    The present invention contemplates that the exhalation insert can be either integral with the fluid connector or removable therefrom. If removable, the present invention contemplates that different configurations for the exhalation insert can be provided in the receptacle to select the amount of exhaust flow through the flow apparatus. 
         [0056]    In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word “comprising” or “including” does not exclude the presence of elements or steps other than those listed in a claim. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. In any device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain elements are recited in mutually different dependent claims does not indicate that these elements cannot be used in combination. 
         [0057]    Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.