Abstract:
A breast pump system includes a one-size-fits-all funnel for fittingly receiving the breast of a lactating woman. In some examples, the funnel has a superelliptical opening that provides a smooth, naturally occurring vent at the funnel&#39;s inlet. The vent places the breast-to-funnel circumferential seal closer to the narrow end of the funnel, rather than at the funnel&#39;s wider inlet. The seal being closer to the nipple ensures that the nipple remains centrally aligned within the system&#39;s nipple-receiving receptacle, regardless of the size and shape of the breast.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    The subject invention generally pertains to human breast milk collection systems and more specifically to a vented breast fitting funnel 
       BACKGROUND 
       [0002]    The superellipse was the name given by the poet and scientist, Piet Hein, for a distinctive elliptical shape defined by a certain formula. The shape of a superellipse appears to be a blend of a circle, an ellipse and a square, but it is not a rounded square. One of the most notable applications of a superellipse was in a proposal that Hein submitted in response to a challenge from the city of Stockholm, Sweden for the design of an efficient roundabout for their city square. In his proposal, Hein explained his design as follows: 
         [0003]    “Man is the animal that draws lines which he himself then stumbles over. In the whole pattern of civilization there have been two tendencies, one toward straight lines and rectangular patterns and one toward circular lines. There are reasons, mechanical and psychological, for both tendencies. Things made with straight lines fit well together and save space. And we can move easily—physically or mentally—around things made with round lines. But we are in a straitjacket, having to accept one or the other, when often some intermediate form would be better. To draw something freehand—such as the patchwork traffic circle they tried in Stockholm—will not do. It isn&#39;t fixed, isn&#39;t definite like a circle or square. You don&#39;t know what it is. It isn&#39;t esthetically satisfying. The super-ellipse solved the problem. It is neither round nor rectangular, but in between. Yet it is fixed, it is definite  it has a unity.” 
         [0004]    The shape of superellipses and roundabouts may be unrelated to the shape of funnels found in conventional breast milk collection devices used for collecting breast milk from a lactating woman. Such funnels, or breast guides, have a round inlet opening for fittingly receiving the woman&#39;s breast. In many cases, a vacuum pump provides cyclical periods of positive and negative pressure to the milk collection device. During periods of negative pressure (subatmospheric pressure), vacuum delivered to the device withdraws a small discrete volume of milk from the breast and conveys that charge of milk to a small charging chamber. During each period of positive pressure, lightly pressurized air relaxes the breast momentarily while at the same time forces the charge of milk from the charging chamber to a larger milk storage chamber. The cycle repeats until the storage chamber is full or until the woman is finished “pumping.” 
         [0005]    The funnel, or breast guide, of some breast pump systems are worn within the cup of a common brassiere. Examples of such systems are disclosed in U.S. Pat. Nos. 7,559,915; 8,118,772; and 8,702,646; all of which are incorporated herein by reference. Other breast pump systems have funnels that are handheld or are supported by or extend through a special purpose brassier. Examples of such systems are disclosed in U.S. Pat. Nos. 5,941,847; 7,094,217; and 8,057,452; all of which are incorporated herein by reference. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a cross-sectional side view of an example milk collection device constructed in accordance with the teachings disclosed herein. 
           [0007]      FIG. 2  is a combination schematic diagram and cross-sectional side view similar to  FIG. 1  but showing the milk collection device as part of an example breast pump system. 
           [0008]      FIG. 3  is a view similar to  FIG. 2  but showing the system during a positive pressure period rather than a suction pressure period. 
           [0009]      FIG. 4  is a cross-sectional side view of the milk collection device shown in  FIGS. 1-3 , but showing the device fully tipped over and pointed down. 
           [0010]      FIG. 5  is a cross-sectional view of the milk collection device shown in  FIG. 1  but showing the device in a disassembled cleaning state. 
           [0011]      FIG. 6  is a cross-sectional view similar to  FIG. 1  but with the outer shell omitted. 
           [0012]      FIG. 7  is a cross-sectional view showing a portion of  FIG. 6 . 
           [0013]      FIG. 8  is a cross-sectional view taken along line  8 - 8  of  FIG. 7 . 
           [0014]      FIG. 9  is a cross-sectional view showing a portion of  FIG. 6 . 
           [0015]      FIG. 10  is a cross-sectional view taken along line  10 - 10  of  FIG. 9 . 
           [0016]      FIG. 11  is a cross-sectional view showing a portion of  FIG. 6 . 
           [0017]      FIG. 12  is a cross-sectional view taken along line  12 - 12  of  FIG. 11 . 
           [0018]      FIG. 13  is a cross-sectional view showing a portion of  FIG. 6 . 
           [0019]      FIG. 14  is a cross-sectional view taken along line  14 - 14  of  FIG. 13 . 
           [0020]      FIG. 15  is a cross-sectional view similar to  FIG.10  but showing an airflow pattern during a negative pressure period (first period). 
           [0021]      FIG. 16  is a cross-sectional view similar to  FIG. 15  but showing an airflow pattern during a positive pressure period (second period). 
           [0022]      FIGS. 17 and 18  are illustrations demonstrating an example “vacuum break” concept. 
           [0023]      FIG. 19  is an illustration demonstrating another example “vacuum break” concept. 
           [0024]      FIG. 20  is a cross-sectional view similar to  FIG. 1  but showing another example milk collection device constructed in accordance with the teachings disclosed herein. 
           [0025]      FIG. 21  is a cross-sectional view similar to  FIG. 1  but showing another example milk collection device constructed in accordance with the teachings disclosed herein. 
           [0026]      FIG. 22  is a cross-sectional view similar to  FIG. 1  but showing of another example milk collection device constructed in accordance with the teachings disclosed herein. 
           [0027]      FIG. 23  is a cross-sectional side view of an example breast pump system constructed in accordance with the teachings disclosed herein, wherein a breast is about to engage the system&#39;s breast guide. 
           [0028]      FIG. 24  is a cross-sectional side view similar to  FIG. 23  but showing initial contact between the breast and the breast guide. 
           [0029]      FIG. 25  is a cross-sectional side view similar to  FIG. 24  but showing the breast in deeper contact with the breast guide. 
           [0030]      FIG. 26  is a cross-sectional side view similar to  FIG. 25  but showing vacuum drawing the breast even further into the breast guide. 
           [0031]      FIG. 27  is a cross-sectional side view showing a milk collection system similar to the system shown in  FIGS. 23-26  but without ventilating means for ensuring proper alignment of a nipple within a nipple receptacle. 
           [0032]      FIG. 28  is a cross-sectional side view similar to  FIG. 28  but showing the nipple misaligned with the nipple receptacle. 
           [0033]      FIG. 29  is a cross-sectional side view of an example breast guide and nipple receptacle usable in the milk collection device shown in  FIGS. 23-26 . 
           [0034]      FIG. 30  is a cross-sectional view taken along line  30 - 30  of  FIG. 29 . 
           [0035]      FIG. 31  is a cross-sectional view taken along line  31 - 31  of  FIG. 29 . 
           [0036]      FIG. 31A  is a cross-sectional view similar to  FIG. 31  but showing a breast within the breast guide. 
           [0037]      FIG. 32  is a cross-sectional view taken along line  32 - 32  of  FIG. 29 . 
           [0038]      FIG. 33  is a cross-sectional side view of an example breast guide and nipple receptacle usable in the milk collection device shown in  FIGS. 23-26 . 
           [0039]      FIG. 34  is a cross-sectional view taken along line  34 - 34  of  FIG. 33 . 
           [0040]      FIG. 35  is a cross-sectional view taken along line  35 - 35  of  FIG. 33 . 
           [0041]      FIG. 35A  is a cross-sectional view similar to  FIG. 35  but showing a breast within the breast guide. 
           [0042]      FIG. 36  is a cross-sectional view taken along line  36 - 36  of  FIG. 33 . 
           [0043]      FIG. 37  is a cross-sectional side view of an example breast guide and nipple receptacle usable in the milk collection device shown in  FIGS. 23-26 . 
           [0044]      FIG. 38  is a cross-sectional view taken along line  38 - 38  of  FIG. 37 . 
           [0045]      FIG. 39  is a cross-sectional view taken along line  39 - 39  of  FIG. 37 . 
           [0046]      FIG. 39A  is a cross-sectional view similar to  FIG. 39  but showing a breast within the breast guide. 
           [0047]      FIG. 40  is a cross-sectional view taken along line  40 - 40  of  FIG. 37 . 
           [0048]      FIG. 41  is a cross-sectional side view of an example breast guide and nipple receptacle usable in the milk collection device shown in  FIGS. 23-26 . 
           [0049]      FIG. 42  is a cross-sectional view taken along line  42 - 42  of  FIG. 41 . 
           [0050]      FIG. 43  is a cross-sectional view taken along line  43 - 43  of  FIG. 41 . 
           [0051]      FIG. 44  is a cross-sectional view taken along line  44 - 44  of  FIG. 41 . 
           [0052]      FIG. 45  is a cross-sectional side view of an example breast guide and nipple receptacle usable in the milk collection device shown in  FIGS. 23-26 . 
           [0053]      FIG. 46  is a cross-sectional view taken along line  46 - 46  of  FIG. 45 . 
           [0054]      FIG. 47  is a cross-sectional view taken along line  47 - 47  of  FIG. 45 . 
           [0055]      FIG. 48  is a cross-sectional view taken along line  48 - 48  of  FIG. 45 . 
           [0056]      FIG. 49  is a cross-sectional side view of an example breast guide and nipple receptacle usable in the milk collection device shown in  FIGS. 23-26 . 
           [0057]      FIG. 50  is a cross-sectional view taken along line  50 - 50  of  FIG. 49 . 
           [0058]      FIG. 51  is a cross-sectional view taken along line  51 - 51  of  FIG. 49 . 
           [0059]      FIG. 52  is a cross-sectional view taken along line  52 - 52  of  FIG. 49 . 
       
    
    
     DETAILED DESCRIPTION 
       [0060]      FIGS. 1-16  show various views of an example breast pump system  10  that includes a milk collection device  12  with means for preventing milk  14  from backflowing to a vacuum pump  16 .  FIGS. 17-19  illustrate the underlying operating principle of vacuum breakers. And  FIGS. 21-22  show variations of the system design. The general design isolates a subatmospheric air flow path  102  ( FIG. 10 ) from a milk flow path  20  ( FIG. 9 ) even if milk collection device  12  it tipped completely over ( FIG. 4 ). The vacuum breaker concept keeps fluids separated without using conventional baffles, which inherently have crevices that can be difficult to clean. 
         [0061]    As an overview of the breast pump system&#39;s general construction, milk collection device  12  comprises four main parts: a funnel-shaped breast receiver  22 , a domed outer shell  24 , a fluid exchanger  26 , and a unidirectional valve  28  (e.g., a check valve, a duckbill check valve, a reed valve, a ball check valve, a diaphragm check valve, a swing check valve, etc.).  FIG. 1  shows these for main parts in an assembled operating state with the parts being positioned as a unit in a predetermined orientation, and  FIG. 5  shows them in a disassembled cleaning state. Breast receiver  22  itself comprises a breast guide  30  and a nipple receptacle  32 . Breast guide  30  is generally conical for fittingly receiving a breast  34  of a lactating woman  36 , and nipple receptacle  32  is tubular and defines a nipple chamber  36  for receiving a nipple  38  of breast  34 . 
         [0062]    In some examples, outer shell  24  removably connects to a flange  40  of breast receiver  22  to define a milk storage chamber  42  between outer shell  24  and breast receiver  22 . Fluid exchanger  26  is coupled to breast receiver  22  to provide means for strategically directing milk  14  and air  44  within milk collection device  12 . Valve  28  establishes a milk charging chamber  46  between nipple receptacle  36  and storage chamber  42 . In some examples, charging chamber  46  is cycled between positive and negative pressure to draw discrete quantities of expressed milk from nipple receptacle  36 . During periods of positive pressure, charging chamber  46  discharges each discrete quantity or charge through valve  28  to storage chamber  42 . 
         [0063]    To provide charging chamber  46  with air  44  cyclically at subatmospheric pressure and positive or atmospheric pressure, a suction tube  48  couples milk collection device  12  to vacuum pump  16 . The term, “vacuum pump,” refers to any device that provides subatmospheric pressure continuously, cyclically, or at least momentarily. Vacuum pump  16  is schematically illustrated to represent all types of vacuum pumps, examples of which include, but are not limited to, a diaphragm pump, a bellows pump, a piston pump, a reciprocating pump, a peristaltic pump, a positive displacement pump, a gear pump, a lobed rotor pump, a screw compressor, a scroll compressor, and a rotary vane pump. 
         [0064]    The breast pump system&#39;s structure and operation can be further understood with additional definitions and explanations of some detailed features of the system. Nipple receptacle  36  has an inner curved wall surface  50 , an outer curved wall surface  52 , a proximate end  54  and a distal end  56 . The nipple receptacle&#39;s tubular shape defines a longitudinal centerline  58  and nipple chamber  30 . A minimum radial distance  60  exists between longitudinal centerline  58  and inner curved wall surface  50 , wherein the minimum radial distance is measured perpendicular to centerline  58 . Nipple receptacle  36  extends longitudinally in a forward direction  62  (parallel to centerline  58 ) from proximate end  54  to distal end  56 . In some examples, nipple chamber  36  extends farther forward than distal end  56  of nipple receptacle  32 ; however, any part of nipple receptacle  32  that happens to extend farther forward than nipple chamber  36  is considered an extension beyond distal end  56  and thus is not considered the receptacle&#39;s distal end  56  itself. In some examples, the most forward point of nipple chamber  36  is at a domed concave surface  64  on fluid exchanger  26 . Surface  64  being domed rather than flat makes fluid exchanger  26  easier to clean after fluid exchanger  26  is separated from breast receiver  22 . 
         [0065]    When breast receiver  22  and valve  28  are attached to fluid exchanger  26 , the resulting assembly produces various fluid passages, chambers and sealing interfaces. Upon disassembly, the passages, chambers and sealing interfaces become more open for easier cleaning and sanitizing. Examples of such passages, chambers and sealing interfaces include charging chamber  46 , nipple chamber  36 , a milk passage  66  for conveying milk  14  from nipple chamber  36  to charging chamber  46 , a valve outlet  68  that periodically discharges discrete volumes of milk  14  to storage chamber  42 , an air duct  70  that connects suction tube  48  in fluid communication with charging chamber  46 , a primary sealing interface  72 , and a secondary sealing interface  74 . 
         [0066]    In some examples, system  10  operates in an alternating manner of suction periods and pressurized periods. During suction periods, as shown in  FIGS. 2 and 15 , vacuum pump  16  applies suction or air at subatmospheric pressure to a remote end  76  of suction tube  48 . At least some of the vacuum reaches nipple chamber  36  to draw milk expressed from nipple  38 . The expressed milk  14  flows from nipple chamber  36 , flows through milk passage  66 , and collects at the bottom of charging chamber  46 . The negative air pressure produced by vacuum pump  16  creates a first current of air  78  ( FIG. 15 ) that effectively moves from nipple chamber  36  and effectively flows in series through milk passage  66 , through charging chamber  46 , through air duct  70  ( FIGS. 9 ,  10 ,  15  and  16 ), through suction tube  48 , and to vacuum pump  16 . The terms, “effectively moves” and “effectively flows” means that there is some air movement from an upstream point toward a downstream point, but the air at the upstream point will not necessarily reach the downstream point, due to the travel distance and/or other flow constraints. 
         [0067]    During pressurized periods, as shown in  FIGS. 3 and 16 , vacuum pump  16  applies positive air pressure to suction tube  48 . The positive pressure creates a second current of air  80  that effectively flows in series through suction tube  48 , through air duct  70 , through milk passage  66 , and into nipple chamber  36 . The air pressure in charging chamber  46  forces milk  14  (collected during the previous suction period) from charging chamber  46 , down through valve  28 , and into storage chamber  42 . The air pressure in nipple chamber  36  allows breast  34  to relax prior to the next suction period. 
         [0068]    The alternating cycle of suction and pressure is repeated for as long as desired or until storage chamber  42  is filled to some predetermined capacity. Upon completion of the pumping process, any suitable means can be used for transferring collected milk from storage chamber  42  to a bottle or to some other convenient storage container. One example method for transferring milk  14  from storage chamber  42  is to pull suction tube  48  out from within an opening  82  ( FIG. 5 ) between breast receiver  22  and outer shell  24 , and then pour collected milk  14  out through opening  82 . Another method is to turn milk collection device  12  over (e.g.,  FIG. 4 ), remove breast receiver  22  from outer shell  24 , and simply pour milk  14  out from shell  24 . 
         [0069]    Although  FIG. 4  is referred to illustrate means for emptying milk  14  collected in storage chamber  42 , the primary purpose of  FIG. 4  is to show how well device  12  tolerates a completely tipped-over condition while still preventing milk  14  from backflowing into suction tube  48 . Device  12  has three features that prevent milk backflow. One, in the tipped-over position, air duct  70  remains elevated above milk passage  66 . Two, a circumferential seal  74  ( FIG. 12 ) exists between air duct  70  and milk  14  in nipple chamber  36 . Three, air duct  70  connects to charging chamber  46  at two spaced apart openings  86  and  88  (see  FIG. 15  and the explanation referencing  FIGS. 17 ,  18  and  19 ) 
         [0070]    Preventing milk  14  from entering suction tube  48  is important for several reasons. Milk droplets or even a milk film trapped inside a narrow suction tube can be very difficult to thoroughly clean and sanitize. If left unclean, the trapped milk can contaminate future milk collections. Also, if milk in suction tube  48  migrates into vacuum pump  16 , the milk can be even more difficult to remove and can possibly damage or destroy pump  16 . Tolerating such unsanitized conditions is generally unheard of in the fields of medicine and food processing. 
         [0071]      FIG. 6  serves as somewhat of an index drawing for a subsequent series of cross-sectional views. The views in the series are shown in sets of two and are identified as  FIGS. 7-8 ,  FIGS. 9-10 ,  FIGS. 11-12 , and  FIGS. 13-14 .  FIGS. 7-8  show primary sealing interface  72  between an outer diameter of breast receiver  22  and an inner diameter of fluid exchanger  26 . Primary sealing interface  72  is a relatively tight seal that extends 360 degrees circumferentially around centerline  58  to isolate localized pressure or vacuum within charging chamber  46  while the surrounding storage chamber  42  is at atmospheric pressure. In some examples, to ensure a positive seal, interface  72  tapers at 3-degrees in a lengthwise direction with reference to centerline  58 . 
         [0072]      FIGS. 9-10  show one example of air duct  70  connecting vacuum tube  48  in fluid communication with charging chamber  46 . In this example, air duct  70  comprises a supply port  84  at a connection end  90  of suction tube  48 , a first opening  86  at charging chamber  46 , and a second opening  88  at charging chamber  46 . To connect tube  48  to supply port  84 , connection end  90  of suction tube  48  press-fits into a tapered bore  92  of fluid exchanger  26 . A fork  94  (e.g., one path leading to two) in air duct  70  connects supply port  84  in fluid communication with openings  86  and  88 . Features  84 ,  86  and  88  of  FIG. 10  correspond respectively to points  84 ′,  86 ′ and  88 ′ of  FIG. 18 . Features  84 ,  86  and  88  of  FIG. 10  also correspond respectively to points  84 ″,  86 ″ and  88 ″ of  FIG. 19 . 
         [0073]    To apply the “vacuum break” concept illustrated in  FIGS. 17 and 18 , fork  94  straddles nipple receptacle  36  so that openings  86  and  88  are spaced apart in a lateral direction  96  with the nipple receptacle longitudinal centerline  58  being laterally interposed between openings  86  and  88  (dimensions  98  and  100 ). In some examples, nipple receptacle  36  is flanked by openings  86  and  88 , which means that the nipple&#39;s longitudinal centerline  58  is laterally between openings  86  and  88 , as shown in  FIG. 10 . The spaced-apart distance and elevation of openings  86  and  88  can be increased by increasing the diameter of a flange  99  to which valve  28  is attached. 
         [0074]    Still referring to  FIG. 10 , some examples of air duct  70  define a flow path  102  from supply port  84  to first opening  86 , wherein a curved section of flow path  102  extends circumferentially an angular distance  104  of at least thirty degrees to avoid having to create an alternate flow path in front of or through nipple chamber  36 . In some examples, at least one section  106  of flow path  102  lies within a radial gap  108  between fluid exchanger  26  and the nipple receptacle&#39;s outer curved wall surface  52 . Upon disassembling device  12  to its disassembled cleaning state ( FIG. 5 ), section  106  of flow path  102  is split apart, which makes flow path  102  and air duct  70  much more accessible for cleaning. 
         [0075]      FIGS. 11 and 12  show secondary sealing interface  74  radially between fluid exchanger  26  and the nipple receptacle&#39;s outer curved wall surface  52 . Secondary sealing interface  74  provides a barrier that prevents milk  14  from flowing directly from nipple chamber  36  to air duct  70 .  FIG. 11  shows air duct  70  being between primary sealing interface  72  and secondary sealing interface  74 . 
         [0076]    Primary sealing interface  72  is the more critical seal of the two because primary sealing interface  72  is subjected to an appreciable pressure differential between supply port  84  and storage chamber  42 . Secondary sealing interface  74 , however, is not as critical because the pressure differential between supply port  84  and nipple chamber  36  is nearly zero. Consequently, in some examples, primary sealing interface  72  is made to be a tighter seal than secondary sealing interface  74 . In other words, when breast receiver  22  is snugly inserted into fluid exchanger  26 , the radial forces at primary sealing interface  72  is greater than that at secondary sealing interface  74 . 
         [0077]    It can be important to have primary sealing interface  72  be the dominant seal because when breast receiver  22  is inserted into fluid exchanger  26 , something has to “bottom out” first to stop the relative insertion movement of breast receiver  22  into fluid exchanger  26 . If secondary sealing surface  74  or distal end  56  abutting domed surface  64  were to be the first parts to bottom out, that might leave some radial clearance or leak path at primary sealing interface  72 . Intentionally making primary sealing interface  72  be the first to bottom out, loosens the manufacturing tolerances at other near bottom-out locations, thus increasing assembly reliability, reducing tooling costs, and simplifying manufacturing. 
         [0078]      FIGS. 13 and 14  show milk passage  66  between charging chamber  46  and nipple chamber  36 .  FIGS. 14 and 5  show how an irregular shaped upper flange  110  of valve  28  serves as a means for “clocking” or rotationally aligning valve  28  to fluid exchanger  26 . Such alignment can be important to avoid interference between a lower end  112  of valve  28  and outer shell  24 . For instance, if valve  28  were rotated ninety degrees (about a vertical axis  114 ) from the position shown in  FIG. 1 , the valve&#39;s lower end  112  might press up against outer shell  24 , whereby outer shell  24  might hold valve  28  open and prevent it from closing. 
         [0079]      FIGS. 15 and 16  illustrate an example breast pump method operating during a first suction period ( FIGS. 2 and 15 ) and a second pressure period ( FIGS. 3 and 16 ).  FIG. 15  shows during the first period, directing first current of air  78  in a first curved upward direction circumferentially across a first outer convex wall surface  116  of nipple receptacle  32 .  FIG. 15  also shows during the first period, directing a third current of air  118  in a second curved upward direction circumferentially across the nipple receptacle&#39;s first outer convex wall surface  116 .  FIG. 16  shows during the second period, directing second current of air  80  in a first curved downward direction circumferentially across the nipple receptacle&#39;s first outer curved wall surface  116 .  FIG. 16  also shows during the second period, directing a fourth current of air  120  in a second curved downward direction circumferentially across the nipple receptacle&#39;s first outer curved wall surface  116 , wherein nipple receptacle  32  is interposed between first current of air  78  and third current of air  118  during the first period, and nipple receptacle  32  is interposed between second current of air  80  and fourth current of air  120  during the second period. 
         [0080]      FIGS. 17 and 18  illustrates the concept of a vacuum breaker as a means for preventing a liquid  122  from backflowing up to a suction source  124 . Liquid  122  only reaches suction source  124  when both openings  86 ′ and  88 ′ are submerged in liquid  122 , as shown in  FIG. 17 . If only one opening  86 ′ is submerged and the other opening  88 ′ is exposed to air  44 , as shown in  FIG. 18 , air  44  readily supplies the volume drawn in by suction source  124 . Through a given opening, air can flow about thirty times easier than water. Consequently, only a slight pressure differential is needed for air  44  to rush through opening  88 ′ to suction source  124 . That slight pressure differential creates only a slight pressure head  126  that is unable to lift liquid  122  from opening  86 ′ to suction source  124 . 
         [0081]      FIG. 19  provides another example of illustrating a vacuum breaker concept. This example involves the use of a residential water line  128 , an outdoor faucet  130 , a simplified vacuum breaker  132 , and a garden hose  134  partially submerged in a bucket  136  of contaminated water  138 . In this example, if unusual adverse conditions create a vacuum in water line  128 , clean outdoor air  44  rather than contaminated water  138  will be drawn into water line  128 . 
         [0082]      FIGS. 20 ,  21  and  22  show various design modifications.  FIG. 20  shows an altered milk passage  66 ′ created by a beveled edge  140  at the end of a nipple receptacle  32 ′.  FIG. 21  shows an altered milk passage  66 ″ created by a notched edge  142  at the end of a nipple receptacle  32 ″.  FIG. 22  shows that a stubbier fluid exchanger  26 ′ and a less protruding outer shell  24 ′ can be used when air duct  4  curves around the sides of the nipple receptacle rather than in front of it. The stubbier fluid exchanger  26 ′ also reduces the effective volume of charging chamber  46 , which can be beneficial when using certain low displacement vacuum pumps. 
         [0083]    In addition or alternatively,  FIGS. 23-26  show an example breast pump system  150  with means for ensuring that nipple  38  is properly positioned within a nipple receptacle  152 . In this example, breast pump system  150  comprises a milk collection device  154  and a vacuum pump  155 . Milk collection device  154  comprises a funnel-shaped breast guide  156 , nipple receptacle  152 , a fluid exchanger  158 , and an outer shell  160 . Breast pump system  150 , milk collection device  154 , breast guide  156 , nipple receptacle  152 , fluid exchanger  158 , outer shell  160  and vacuum pump  155 , shown in  FIGS. 23-26 , respectively correspond to breast pump system  10 , milk collection device  12 , breast guide  30 , nipple receptacle  32 , fluid exchanger  26 , outer shell  24  and vacuum pump  16 , shown in  FIGS. 1-16 . 
         [0084]      FIG. 23  shows milk collection device  154  being installed onto breast  34 .  FIG. 24  shows initial light contact between breast  34  and breast guide  156  at points  162  and  164 . Upon subsequently applying additional force  166  to device  154 , as shown in  FIG. 25 , contact between breast  34  and breast guide  156  moves deeper into breast guide  156 , as indicated by points  168  and  170 .  FIG. 26  shows vacuum pump  155  applying vacuum that draws nipple  38  into the proper position within nipple receptacle  152 . With nipple  38  properly positioned, breast pump system  150  can be operated in a normal manner as described with reference to breast pump system  10 . 
         [0085]    If breast pump system  150  were to lack means for ensuring proper positioning of nipple  38  within nipple receptacle  152 , nipple  38  could become misaligned within the nipple chamber, as shown in  FIGS. 27 and 28 . For example, if sealing contact were to occur at points  172  and  174 , as shown in  FIG. 27 , subsequent vacuum could draw breast  34  into the milk collection device. However, if more contact pressure or friction exists at point  172  than at point  174 , then the area of breast  34  at point  172  could be held stationary while sliding  176  occurs at point  174 . Such localized sliding would shift nipple  38  upward, as indicated by arrows  178  and  180 . In some cases, as shown in  FIG. 28 , nipple  38  could become so terribly misaligned and obstructed that breast  34  fails to express milk. 
         [0086]    This problem becomes more evident when one considers the suction force of the vacuum as applied across the wide or narrow end of a funnel shaped breast guide. In some cases, the vacuum is −2 psig, the diameter of the wide end is about 70 mm, and the diameter of the narrow end is about 26 mm. In such an example, vacuum sealed at the narrow end could draw a breast in with a reasonable 1.6 lbs of force. Vacuum sealed at the wide end, however, could draw a breast in with about 12 lbs of force, which is greater than the weight of some bowling balls and certainly enough to pull a breast off center. 
         [0087]    Such a problem can be more likely to occur if the shape or size of a breast guide does not perfectly match the shape or size of breast  34 . It can be impractical and expensive for manufacturers to provide custom shaped breast guides to fit breasts of various sizes. Even a given breast can change in size and shape. To overcome this problem, various examples of breast guide  156  (e.g., breast guides  156   a - f ) are more adapted to fitting breasts of various shapes and sizes. Breast guide  156  provides a universal fit by initially establishing a seal at a narrow end  182  of breast guide  156 , near nipple receptacle  152 , while at the same time venting a wide end  184  of breast guide  156 . 
         [0088]    In the example shown in  FIGS. 29-32 , breast guide  156   a  comprises a tubular wall  186   a  converging from a wide end  184   a  to a narrow end  182   a,  wherein narrow end  182   a  adjoins nipple receptacle  152 . A tubular wall  186   a  defines a breast-receiving chamber  188   a  within breast guide  156   a.  Breast guide  156   a  and nipple receptacle  152  define a longitudinal centerline  190  extending centrally through both breast-receiving chamber  188   a  and nipple receptacle  152 . Breast-receiving chamber  188   a  has a cross-sectional area  192   a  of varying size lying perpendicular to centerline  190 . Cross-sectional area  192   a  extends radially from centerline  190  to the interior surface of tubular wall  186   a  and can be taken across any point along centerline  190  between ends  184   a  and  182   a.  Cross-sectional area  192   a  is larger at wide end  184   a  than at narrow end  182   a.  At wide end  184   a  and/or at an intermediate location  196   a  between ends  184   a  and  182   a,  cross-sectional area  192   a  has a noncircular shape (e.g., superellipse, regular ellipse, rectangle, rounded rectangle, square, rounded square, irregular, polygon, etc.). 
         [0089]    In this particular example, the noncircular shape of area  192   a  (e.g., at wide end  184   a  and/or at intermediate location  196   a ) is a superellipse defined by an equation (in the x, y, Cartesian coordinate system) where the sum of a first value and a second value is equal to a total constant (e.g., a total constant equal to one), wherein the first value is the absolute value of a first ratio raised to the nth power, the second value is the absolute value of a second ratio raised to the nth power, the first ratio is the x-coordinate divided by a first constant denominator, the second ratio is the y-coordinate divided by a second constant denominator. In the example shown in  FIGS. 30-32 , the value of the exponent “n” equals three, and the first constant denominator equals the second constant denominator (a=b). The actual values of the constant denominators and the total constant determine the scale of cross-sectional area  192   a  at wide end  184   a  and/or intermediate location  196   a.  In some examples, the equation is expressed as |x/a| n +|y/b| n =1, where “a” is the first constant denominator, “b” is the second constant denominator, “n” is the exponent having a value of “3,” and “1” is the total constant. 
         [0090]    In the example illustrated in  FIGS. 29-32 , the cross-sectional area  192   a  is a superellipse at both wide end  184   a  ( FIG. 30 ) and at intermediate location  196   a  ( FIG. 31 ). From intermediate location  196   a,  cross-sectional area  192   a  transitions to being substantially circular at narrow end  182   a,  as shown in  FIG. 32 . The circular shape of narrow end  182   a  provides an effective circumferential seal with breast  34  near nipple  38  while the superelliptical shape at intermediate location  196   a  provides at least one air vent passageway  198   a  between breast  34  and tubular wall  194   a,  as shown in  FIG. 31A . Establishing a circumferential seal near nipple  38  at narrow end  182   a  (e.g., at points  168  and  170  of  FIG. 25 ) in combination with wide end  184   a  and/or intermediate location  196   a  being vented enables vacuum to draw nipple  38  straight into nipple receptacle  152 . 
         [0091]    In some examples where breast guide  156  defines a vent or an air vent passageway, the vent passageway exists within a radial gap (e.g., vent passageway  198   a ) between the inner surface of a tubular wall (e.g., tubular wall  186   a - e ) and a circle inscribed within the tubular wall. In  FIGS. 31A ,  35 A, and  39 A; breast  34  is a physical example of such a circle. 
         [0092]    To provide breast guide  156  with a more open vent airway, breast guide  156   b  is shaped as shown in  FIGS. 33-36 . In this example, the superelliptical formula applied in  FIGS. 34 and 35  has an “n” exponent equal to “4” rather than “3” ( FIGS. 30 and 31 ). 
         [0093]    Similar to breast guide  156   a  of  FIGS. 29-32 , breast guide  156   b  of  FIGS. 33-36  comprises a tubular wall  186   b  converging from a wide end  184   b  to a narrow end  182   b,  wherein narrow end  182   b  adjoins nipple receptacle  152 . Tubular wall  186   b  defines a breast-receiving chamber  188   b  within breast guide  156   b.  Breast guide  156   b  and nipple receptacle  152  define longitudinal centerline  190  extending centrally through both breast-receiving chamber  188   b  and nipple receptacle  152 . Breast-receiving chamber  188   b  has a cross-sectional area  192   b  of varying size lying perpendicular to centerline  190 . Cross-sectional area  192   b  extends radially from centerline  190  to the interior surface of tubular wall  186   b  and can be sliced across any point along centerline  190  between ends  184   b  and  182   b.  Cross-sectional area  192   b  is larger at wide end  184   b  than at narrow end  182   b.  At wide end  184   b  and/or at an intermediate location  196   b  between ends  184   b  and  182   b,  cross-sectional area  192   b  has a noncircular shape. 
         [0094]    In this example, the noncircular shape of area  192   b  (e.g., at wide end  184   b  and/or at intermediate location  196   b ) is a superellipse similar to that of  FIGS. 30 and 31 . In this example, however, the value of the exponent “n” equals four; although, the first constant denominator equals the second constant denominator (a=b). In this case, the equation is expressed as |x/a| 4 +|y/b| 4 =1. 
         [0095]    In the example illustrated in  FIGS. 33-34 , the cross-sectional area  192   b  is a superellipse at both wide end  184   b  ( FIG. 34 ) and at intermediate location  196   b  ( FIG. 35 ). From intermediate location  196   b,  cross-sectional area  192   b  transitions to being substantially circular at narrow end  182   b,  as shown in  FIG. 36 . The circular shape of narrow end  182   b  provides an effective circumferential seal with breast  34  near nipple  38  while the superelliptical shape at intermediate location  196   b  provides at least one air vent passageway  198   b  between breast  34  and tubular wall  186   b,  as shown in  FIG. 35A . Establishing a circumferential seal near nipple  38  at narrow end  182   b  (e.g., at points  168  and  170  of  FIG. 25 ) in combination with wide end  184   b  and/or intermediate location  196   b  being vented enables vacuum to draw nipple  38  straight into nipple receptacle  152 . 
         [0096]    To provide breast guide  156  with an even more open vent airway, breast guide  156   c  is shaped as shown in  FIGS. 37-40 . In this example, the superelliptical formula applied in  FIGS. 38 and 39  has an “n” exponent equal to “5” rather than “3” ( FIG. 30 and 31 ) or “4” ( FIGS. 34 and 35 ) 
         [0097]    Similar to breast guide  156   a  of  FIGS. 29-32 , breast guide  156   c  of  FIGS. 37-40  comprises a tubular wall  186   c  converging from a wide end  184   c  to a narrow end  182   c,  wherein narrow end  182   c  adjoins nipple receptacle  152 . Tubular wall  186   c  defines a breast-receiving chamber  188   c  within breast guide  156   c.  Breast guide  156   c  and nipple receptacle  152  define longitudinal centerline  190  extending centrally through both breast-receiving chamber  188   c  and nipple receptacle  152 . Breast-receiving chamber  188   c  has a cross-sectional area  192   c  of varying size lying perpendicular to centerline  190 . Cross-sectional area  192   c  extends radially from centerline  90  to the interior surface of tubular wall  186   c  and can be taken across any point along centerline  90  between ends  184   c  and  182   c.  Cross-sectional area  192   c  is larger at wide end  184   c  than at narrow end  182   c.  At wide end  184   c  and/or at an intermediate location  196   c  between ends  184   c  and  182   c,  cross-sectional area  192   c  has a noncircular shape. 
         [0098]    In this example, the noncircular shape of area  192   c  (e.g., at wide end  184   c  and/or at intermediate location  196   c ) is a superellipse similar to that of  FIGS. 30 and 31 . In this example, however, the value of the exponent “n” equals five; although, the first constant denominator equals the second constant denominator (a=b). In this case, the equation is expressed as |x/a| 5 +|y/b| 5 =1. 
         [0099]    In the example illustrated in  FIGS. 37-40 , the cross-sectional area  192   c  is a superellipse at both wide end  184   c  ( FIG. 38 ) and at intermediate location  196   c  ( FIG. 39 ). From intermediate location  196   c,  cross-sectional area  192   c  transitions to being substantially circular at narrow end  182   c,  as shown in  FIG. 40 . The circular shape of narrow end  182   c  provides an effective circumferential seal with breast  34  near nipple  38  while the superelliptical shape at intermediate location  196   c  provides at least one air vent passageway  198   c  between breast  34  and tubular wall  186   c,  as shown in  FIG. 39A . Establishing a circumferential seal near nipple  38  at narrow end  182   c  (e.g., at points  168  and  170  of FIG.  25 ) in combination with wide end  184   c  and/or intermediate location  196   c  being vented enables vacuum to draw nipple  38  straight into nipple receptacle  152 . 
         [0100]      FIGS. 41-44  show an example breast guide  156   d  having cross-sectional areas that are rounded squares instead of superellipses. Similar to breast guide  156   a  of  FIGS. 29-32 , breast guide  156   d  of  FIGS. 41-44  comprises a tubular wall  186   d  converging from a wide end  184   d  to a narrow end  182   d,  wherein narrow end  182   d  adjoins nipple receptacle  152 . Tubular wall  186   d  defines a breast-receiving chamber  188   d  within breast guide  156   d.  Breast guide  156   d  and nipple receptacle  152  define longitudinal centerline  190  extending centrally through both breast-receiving chamber  188   d  and nipple receptacle  152 . Breast-receiving chamber  188   d  has a cross-sectional area  192   d  of varying size lying perpendicular to centerline  190 . Cross-sectional area  192   d  extends radially from centerline  190  to the interior surface of tubular wall  186   d  and can be taken across any point along centerline  190  between ends  184   d  and  182   d.  Cross-sectional area  192   d  is larger at wide end  184   d  than at narrow end  182   d.  At wide end  184   d  and/or at an intermediate location  196   d  between ends  189   d  and  182   d,  cross-sectional area  192   d  has a noncircular shape. 
         [0101]    In this example, the noncircular shape of area  192   d  (e.g., at wide end  184   d  and/or at intermediate location  196   d ) is a rounded square. In some examples, cross-sectional area  192   d  is a rounded square at both wide end  184   d  ( FIG. 42 ) and at intermediate location  196   d  ( FIG. 43 ). From intermediate location  196   d,  cross-sectional area  192   d  transitions to being substantially circular at narrow end  182   d,  as shown in  FIG. 44 . The circular shape of narrow end  182   d  provides an effective circumferential seal with breast  34  near nipple  38  while the rounded square shape at intermediate location  196   d  provides at least one air vent passageway between breast  34  and tubular wall  186   d  at the square shape&#39;s rounded corners. Establishing a circumferential seal near nipple  38  at narrow end  182   d  (e.g., at points  168  and  170  of FIG.  25 ) in combination with wide end  184   d  and/or intermediate location  196   d  being vented enables vacuum to draw nipple  38  straight into nipple receptacle  152 . 
         [0102]      FIGS. 45-48  show an example breast guide  156   e  having cross-sectional areas that are nearly circular but with the addition of an air vent passageway  200 . In some examples, air vent passageway  200  is in the form of a groove  202  that is elongate between a wide end  184   e  and the narrow end  182   e  of a tubular wall  186   e.  Tubular wall  186   e  defines a breast-receiving chamber  188   e  within breast guide  156   e.  Breast guide  156   e  and nipple receptacle  152  define longitudinal centerline  190  extending centrally through both breast-receiving chamber  188   e  and nipple receptacle  152 . Breast-receiving chamber  188   e  has a cross-sectional area  192   e  of varying size lying perpendicular to centerline  190 . Cross-sectional area  192   e  extends radially from centerline  190  to the interior surface of tubular wall  186   e  and can be taken across any point along centerline  190  between ends  184   e  and  182   e.  Cross-sectional area  192   e  is larger at wide end  184   e  than at narrow end  182   e.  At wide end  184   e  and/or at an intermediate location  196   e  between ends  184   e  and  182   e,  cross-sectional area  192   e  has a noncircular shape due to the addition of groove  202 . 
         [0103]    In some examples, cross-sectional area  192   e  is noncircular (due to groove  202 ) at both wide end  184   e  ( FIG. 46 ) and at intermediate location  196   e  ( FIG. 47 ). From intermediate location  196   e,  cross-sectional area  192   e  transitions to being substantially circular at narrow end  182   e,  as shown in  FIG. 48 . The circular shape of narrow end  182   e  provides an effective circumferential seal with breast  34  near nipple  38  while groove  202  at intermediate location  196   e  provides at least one air vent passageway between breast  34  and tubular wall  186   e.  Establishing a circumferential seal near nipple  38  at narrow end  182   e  (e.g., at points  168  and  170  of  FIG. 25 ) in combination with wide end  184   e  and/or intermediate location  196   e  being vented enables vacuum to draw nipple  38  straight into nipple receptacle  152 . 
         [0104]      FIGS. 49-52  show an example breast guide  156   f  having cross-sectional areas that are nearly circular but with the addition of an air vent hole  204  extending radially through a tubular wall  186   f  of breast guide  156 E Vent hole  204  is situated between a wide end  184   f  and a narrow end  182   f  of tubular wall  186   f.  Tubular wall  186   f  defines a breast-receiving chamber  188   f  within breast guide  156   f.  Breast guide  156   f  and nipple receptacle  152  define longitudinal centerline  190  extending centrally through both breast-receiving chamber  188   f  and nipple receptacle  152 . Breast-receiving chamber  188   f  has a cross-sectional area  192   f  of varying size lying perpendicular to centerline  190 . Cross-sectional area  192   f  extends radially from centerline  190  to the interior surface of tubular wall  186   f  and can be taken across any point along centerline  190  between ends  184   f  and  182   f.  Cross-sectional area  192   f  is larger at wide end  184   f  than at narrow end  182   f.  At wide end  184   f  and/or at an intermediate location  196   f  between ends  184   f  and  182   f,  cross-sectional area  192   f  is open through air vent hole  204 . 
         [0105]    In some examples, cross-sectional area  192   f  is noncircular (due to hole  204 ) at both wide end  184   f  ( FIG. 50 ) and at intermediate location  196   f  ( FIG. 51 ). From intermediate location  196   f,  cross-sectional area  192   f  transitions to being substantially circular at narrow end  182   f,  as shown in  FIG. 52 . The circular shape of narrow end  182   f  provides an effective circumferential seal with breast  34  near nipple  38  while air vent hole  204  at intermediate location  196   f  provides at least one air vent passageway at breast  34  and tubular wall  186   f.  Establishing a circumferential seal near nipple  38  at narrow end  182   f  (e.g., at points  168  and  170  of  FIG. 25 ) in combination with wide end  184   f  and/or intermediate location  196   f  being vented enables vacuum to draw nipple  38  straight into nipple receptacle  152 . 
         [0106]    For further clarification, the term, “suction tube” refers to any conduit having a tubular wall of sufficient thickness, stiffness, and/or strength to convey air at subatmospheric pressure. In some examples, suction tube  48  is more flexible than outer shell  24 , breast receiver  22 , and/or fluid exchanger  26 . Such tube flexibility makes tube  48  easier to use and fit to fluid exchanger  26 . The term, “coupled to” refers to two members being connected either directly without an intermediate connecting piece or being connected indirectly via an intermediate connecting piece between the two members. The term, “coupled to” encompasses permanent connections (e.g., bonded, welded, etc.), seamless connections (e.g., the two members are of a unitary piece), and separable connections. The term, “opening” of a fluid pathway refers to a cross-sectional area through which fluid is directed to flow in a direction generally perpendicular to the area as guided by the fluid pathway. The term, “radial gap” refers to clearance as measured in a direction perpendicular to longitudinal centerline  58 . The terms, “negative pressure,” “subatmospheric pressure,” and “vacuum” all refer to a pressure that is less than atmospheric pressure. The term, “positive pressure,” refers to a pressure that is greater than atmospheric pressure. Storage chamber  42  is not necessarily for long term storage but rather for collecting and temporarily storing milk  14  as the lactating woman is expressing milk. In some examples, milk collection device  12  includes a slot-and-key  144  alignment feature ( FIG. 8 ) that establishes a certain desired rotational alignment (about longitudinal centerline  58 ) between fluid exchanger  26  and breast receiver  22 . The term, “extending centrally” as it pertains to a centerline extending through a chamber and a receptacle means that when a first circle is inscribed within the chamber and a second circle is inscribed within the receptacle, the center points of the first and second circles lie on the centerline, and the centerline is perpendicular to the planes of both circles. A rounded rectangle is a rectangle with four straight sides and curved corners. The term, “circular” as it pertains to an area means that the area&#39;s perimeter is a continuous 360-degree circle and not just part of circle. The term, “superelliptical” refers to an area having the shape of a superellipse. A superellipse is one example of a regular ellipse. In some examples, the funnel-shaped, breast-receiving breast guides disclosed herein are used in breast milk collection devices that are not necessarily worn within the cup of a special-purpose or ordinary brassier. In some examples, transitioning or blending a funnel-shaped breast guide from a superellipse at one location to a circle at the narrow end of the breast guide is accomplished by gradually reducing the exponent “n” of the superellipse to a value of “2” at the narrow end. In some examples, the funnel-shaped, breast-receiving breast guides disclosed herein are adapted for use with FREEMIE style breast pump systems, wherein FREEMIE is a registered trademark of DAO Health of Sacramento, Calif. In some examples, the funnel-shaped, breast-receiving breast guides disclosed herein are adapted for use with MEDELA style breast pump systems, wherein MEDELA is a registered trademark of Medela Holding AG of Barr, Switzerland. 
         [0107]    Although the invention is described with respect to a preferred embodiment, modifications thereto will be apparent to those of ordinary skill in the art. The scope of the invention, therefore, is to be determined by reference to the following claims: