Abstract:
A hydration monitoring device and system for recording and controlling an individual&#39;s hydration includes an improved fluid flow sensor configured to measure a quantity of fluid transferring from a reservoir to a user in a first fluid flow direction only.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to hydration systems and, more particularly, to apparatus for monitoring the consumption of fluid where the fluid monitoring unit employs an improved impeller that reduces or eliminates “false” fluid consumption readings caused by fluid back flow during hydration sessions. 
     BACKGROUND OF THE INVENTION 
     Accurate monitoring of personal fluid consumption is vital for health. A variety of physiological and medical problems can arise with inappropriate fluid intake. For example, dehydration may increase the risk of cardiovascular strain, reduce heat tolerance, and reduce physical exercise performance. In addition, overhydrating may result in hyponatremia (low blood sodium levels) or other medical problems in some patient groups. 
     Quantifying the pattern and amount of fluid consumed over time by an individual is often fraught with inaccuracies. One approach is to ask individuals to only drink from a given personal container, to keep track of the fluid consumed from that container, and to carefully record the date, time, and amount of liquid consumed. The volume consumed is determined by reading the liquid level from graduations on a fluid container before and after drinking, and then calculating the difference. This approach is difficult under low-light conditions, and incorrect logbook entries are common. Inaccurate or inconsistent measurements often occur with prior art hydration devices, particularly at very low flow rates. At low flow rates, similar to rates produced by small sips, the amount of fluid consumed is often insufficient to fully engage a measurement sensor. 
     In U.S. Pat. No. 6,212,959, issued to Perkins, and incorporated herein by reference, a system for insuring proper human hydration is disclosed that includes an oral-suction-activated flow meter which measures and displays the volume of fluid withdrawn from a reservoir. Perkins suggests that a check valve, to prevent return flow of fluid from the user&#39;s mouth to the reservoir, is often adequate. In particular, Perkins&#39; check valve is suggested as only allowing the flow of fluid in one direction. In use, the fluid flows from a bladder or fluid container, through the check valve and a fluid monitoring unit, and to the user through an outlet tube and mouthpiece. The check valve is meant to prevent the flow of fluid in the opposite direction, i.e., from the fluid monitoring unit back through the check valve. However, in practice, this arrangement appears to trap fluid in the top of the outlet tube (straw or mouthpiece) and requires a bite valve to prevent spillage. This bite valve may be problematic for elderly users or those with oral conditions that impair the user&#39;s ability to bite with sufficient force to actuate the bite valve. 
     In many prior art hydration devices, even if a one-way check valve is placed above the metering device and functions appropriately, there will still be a volume of liquid located within the flow measuring device, but below the check-valve, that will flow back toward its source and through the metering device actuating the metering device and generating erroneous fluid flow data. As a consequence, the check valve may allow fluid to flow in a reverse direction through the impeller thereby diminishing accuracy by allowing the impeller to rotate in an opposite direction. 
     SUMMARY OF THE INVENTION 
     The invention provides a fluid flow sensor configured to measure a quantity of fluid transferring from a reservoir to a user in a first fluid flow direction only. The fluid flow sensor includes a moveable impeller having angled vanes that project radially outwardly from an outer surface. A first spindle projects from a first end and a second spindle projects from a second end such that the first and second spindles are arranged in coaxial relation to a longitudinal axis of the impeller. A plurality of pawls are arranged at an end of the impeller in concentric relation to the second spindle. A magnet is mounted in the impeller so as to be parallel to a longitudinal axis of first and second spindles and a counting coil mounted in spaced relation to the magnet. A first journal having a through-bore arranged to coaxially receive the first spindle such that the first spindle may (i) rotate within the first journal, and (ii) translate longitudinally with respect to the first journal. A second journal having a through-bore arranged to coaxially receive the second spindle such that the second spindle may (i) rotate within the second journal, and (ii) translate longitudinally with respect to the second journal. A plurality of teeth are arranged on the journal in concentric relation to the through-bore so that the impeller is free to rotate when the plurality of teeth are disengaged from the plurality of pawls, and stopped from rotating when the plurality of teeth are engaged by the plurality of pawls. 
     In another embodiment, a hydration monitoring device for recording and controlling an individual&#39;s hydration is provided that includes a fluid reservoir for holding a quantity of fluid. The reservoir includes a tube for transferring fluid from the reservoir via a passage to a fluid flow sensor such that the cumulative quantity of fluid imbibed by the user is measured and recorded. The fluid flow sensor includes a moveable impeller having angled vanes that project radially outwardly from an outer surface. A first spindle projects from a first end and a second spindle projects from a second end. The first and second spindles are arranged in coaxial relation to a longitudinal axis of the impeller with a plurality of pawls arranged at an end of the impeller in concentric relation to the second spindle. A magnet is mounted in the impeller so as to be parallel to a longitudinal axis of first and second spindles and a counting coil mounted in spaced relation to the magnet. A first journal includes a through-bore arranged to coaxially receive the first spindle such that the first spindle may (i) rotate within the first journal, and (ii) translate longitudinally with respect to the first journal. A second journal includes a through-bore arranged to coaxially receive the second spindle such that the second spindle may (i) rotate within the second journal, and (ii) translate longitudinally with respect to the second journal. A plurality of teeth are arranged on the journal in concentric relation to the through-bore. In this way, the impeller is free to rotate when in a first state such that the plurality of teeth are disengaged from the plurality of pawls, and stopped from rotating when in a second state such that the plurality of teeth are engaged by the plurality of pawls. 
     In a further embodiment, a hydration monitoring system for recording and controlling an individual&#39;s hydration is provided that includes a bottle for holding a quantity of fluid including a tube for transferring fluid from the bottle to a fluid flow sensor so that the cumulative quantity of fluid imbibed by the user is measured and recorded. A fluid flow sensor is provided having a moveable impeller including at least four vanes that project radially outwardly from an outer surface. A first spindle projects from a first end and a second spindle projects from a second end. The first and second spindles are arranged in coaxial relation to a longitudinal axis of the impeller with a plurality of ramps arranged at an end of the impeller in concentric relation to the second spindle. A magnet is mounted in the impeller so as to be parallel to a longitudinal axis of first and second spindles and a counting coil mounted in spaced relation to the magnet. A first journal having a through-bore is arranged to coaxially receive the first spindle such that the first spindle may (i) rotate within the first journal, and (ii) translate longitudinally with respect to the first journal. A second journal also includes a through-bore that is arranged to coaxially receive the second spindle such that the second spindle may (i) rotate within the second journal, and (ii) translate longitudinally with respect to the second journal. A plurality of ramps are arranged on the second journal in concentric relation to the through-bore so that the impeller is free to rotate when in a first state such that plurality of ramps are disengaged, and stopped from rotating when in a second state wherein the plurality of ramps are engaged with one another. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the present invention will be more fully disclosed in, or rendered obvious by, the following detailed description of the preferred embodiment of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein: 
         FIG. 1  is a perspective view of a hydration monitoring system including an improved fluid flow sensor in accordance with one embodiment of the invention; 
         FIG. 2  is an exploded perspective view of the cap of the hydration system shown in  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of an under portion of the cap shown in  FIGS. 1 and 2 ; 
         FIG. 4  is a cross-sectional plan view of an impeller assembly formed in accordance with one embodiment of the invention; 
         FIG. 5  is a broken-away, perspective view of a lower portion of an impeller; 
         FIG. 6  is a broken-away, perspective view of a portion of the cylinder housing showing one bearing hub; 
         FIG. 7  is a cross-sectional perspective view of the cap shown in  FIGS. 1 ,  2 , and  3 ; 
         FIG. 8  is a partially perspective, partially cross-sectional view of an impeller assembly formed in accordance with one embodiment of the invention showing the impeller locked and resisting reversed flow rotation, and including an arrow to indicate the general direction of fluid flowing through the assembly; 
         FIG. 9  is a broken-away, perspective view of a lower portion of the impeller assembly shown in  FIG. 8 , illustrating the engagement of the pawl ramps located on the lower portion of the impeller with ramped teeth complementarily located on a bearing-hub; 
         FIG. 10  is a partially perspective, partially cross-sectional view of the impeller assembly shown in  FIG. 8 , but showing the impeller unlocked and allowing free flow rotation, and including an arrow to indicate the general direction of fluid flowing through the assembly; and 
         FIG. 11  is a broken-away, perspective view of the lower portion of the impeller assembly shown in  FIGS. 8-10 , illustrating the disengagement of the pawl ramps located on the lower portion of the impeller from the ramped teeth complementarily located on a bearing-hub so as to allow free forward flow rotation of the impeller. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     This description of preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. The drawing figures are not necessarily to scale and certain features of the invention may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. When only a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. In the claims, means-plus-function clauses, if used, are intended to cover the structures described, suggested, or rendered obvious by the written description or drawings for performing the recited function, including not only structural equivalents but also equivalent structures. It is noted that references in the specification to “one embodiment”, “an embodiment”, “an alternative embodiment”, etc., mean that the structures or procedures being described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, one of ordinary skill in the art would possess the knowledge to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 
     Referring to  FIGS. 1-3  and  7 , an improved flow meter-based hydration system  2  of one embodiment of the invention includes a suction-activated flow meter  4 , an indicator  6 , and a water or liquid reservoir  8 . A tube  10  ( FIG. 7 ) interconnects reservoir  8  with suction-activated flow meter  4  and the user. In operation, suction is applied to a mouthpiece  11  by a user. Mouthpiece  11  communicates with tube  10  via suction-activated flow meter  4 . Located within suction-activated flow meter  4  is a flow metering device or transducer  20 , often in the form of a positive-displacement-type flow meter. Fluid from reservoir  8 , often a container such as a bottle or bladder ( FIG. 1 ), enters fitting  14  at the input of suction-activated flow meter  4  and indicator  6  and flows to metering device  20  through an entrance tube  10   c . From there, the fluid flows through an exit tube  12  into mouthpiece  11  and the user&#39;s mouth. In some embodiments, a one-way check valve  23  is located in exit tube  12  so as to permit the flow of the fluid in one direction only while preventing return flow of fluid toward reservoir  8 . 
     The present invention incorporates an improved flow metering device  20  that includes an impeller assembly  30  ( FIGS. 4-7 ) having a cylindrical housing  31  and an impeller  35 . Cylindrical housing  31  includes a cylindrical outer wall  33  that defines an internal cylindrical cavity  34 , a top journal  36 , and a bottom journal  38  ( FIG. 4 ). Top journal  36  is disposed adjacent to mouthpiece  11 , above impeller  35 , and defines a central through bore  50 . Bottom journal  38  is located in a lower portion of cylindrical housing  31  ( FIGS. 5 and 6 ). A plurality of circumferentially spaced struts  53  project radially inwardly from the inner surface of cylindrical outer wall  33 . Struts  53  join at their ends to form a bearing-hub  58  that defines a central through-bore  60 . Advantageously, bearing-hub  58  includes a plurality of ramped teeth  62  arranged in concentric relation to central through-bore  60  and within cylindrical cavity  34 . Each ramped tooth  62  defines a stop wall  64 . 
     Referring to  FIGS. 4 and 5 , impeller  35  is often cylindrically shaped, and includes at least two angled vanes or blades  66 , and often as many as four, that project radially outwardly from a central axle  70 . Axle  70  may be formed as a solid cylinder having a top spindle  72  and a bottom spindle  73 . Spindles  72  and  73  project from axle  70  in concentric relation to the longitudinal axis of axle  70 . Vanes  66  project radially outwardly from the side surface of axle  70  so that as axle  70  rotates so do vanes  66 . A diametrically magnetized magnet  76  is mounted in an axial bore in axle  70 , so as to be coaxial with the longitudinal axis of spindles  72  and  73 , with north and south poles along the axis of the magnet. A coil  78  ( FIG. 7 ) is mounted on the outside of housing  31 , in proximity with metering device  20 . The orientation of magnet  76  can also be reversed, if need be, with the only effect being a reversal of the polarity of the pulse created in coil  78 . Either polarity can be counted by a microprocessor  80  ( FIG. 7 ) as would be known to those skilled in the art. Advantageously, at the bottom end of axle  70 , surrounding bottom spindle  73 , a plurality of pawl ramps  90  are arranged in concentric relation to axle  70  and bottom spindle  73 . Each pawl ramp defines a stop face  74 , and is located around spindle  73  in complementary relation to plurality of ramped teeth  62  arranged in concentric relation to central through-bore  60  of second hub  58 . 
     Thus, impeller  35  is free to rotate within housing  31  while otherwise positionally constrained by spindles  72  and  73  located within journals  36  and  38 . Advantageously, the length of axle  70 , along its longitudinal axis, is less than the distance between respective journals  36  and  38 , while the distance between spindles  72  and  73  is greater than the distance between journals  36  and  38 . As a result, spindles  72  and  73 , which project outwardly from opposite ends of axle  70 , may be freely received within through-bores  50  and  60  in their respective journals  36 ,  38 , so that axle  70  may shift longitudinally so as to engage only one journal, i.e., bottom journal  38  of bearing-hub  58 , in the absence of fluid flow and top journal  36  when experiencing under fluid flowing toward mouthpiece  11 . In other words, there is “longitudinal play” in the relationship between impeller  35  and bearing journals  36 ,  38  such that spindles  72  and  73  may both rotate about the longitudinal axis of axle  70  and translate longitudinally within through-bores  50  and  60  so as to alter the position of impeller  35  within housing  31  in the longitudinal direction in response to fluid flowing through the system. The diameter of impeller assembly  30  is preferably about one centimeter (0.5 in). Housing  31  is preferably made of a durable polymer material, such as polycarbonate. Alternatively, it could be made of a non-ferrous, i.e., non-magnetic metal, such as aluminum. Axle  70  and vanes  66  are preferably made of polyoxymethylene or another rigid engineering polymer materials. 
     Improved flow meter-based hydration system  2  operates in response to suction being applied to a mouthpiece  11  by a user, such that fluid flows through fitting  14  and metering device  20 . The user applied suction causes fluid to rise through entrance tube  10   c  and through housing  31  of impeller assembly  30 . As this occurs, the fluid impinging upon angled vanes  66  causes impeller  35  to rotate. As impeller  35  rotates, magnet  76  creates a periodically changing magnetic field near the outside surface of housing  31 . The rate of rotation of impeller  35  is determined by the rate of flow of fluid. The number of rotations of impeller  35  is thus proportional to the volume of fluid which flows through housing  31 . Magnetic field lines from magnet  76  extend outside housing  31  in known fashion. At any given location on housing  31 , the magnetic field varies in strength as impeller  35  rotates within journals  36 ,  38  and magnet  76  approaches then retreats from that location. These variations are detected by coil  78 , located in operative proximity to housing  31 . As magnet  76  moves in the vicinity of coil  78 , a current is induced in coil  78  in well-known fashion. Coil  78  is coupled to a microprocessor  80  associated with indicator  6  ( FIG. 7 ). Thus, with one magnet  76  in axle  70  of impeller  33 , each rotation of impeller  35 , the sensor assembly will see one rise and one fall in magnetic field strength. The output of coil  78  thus experiences one positive-going pulse and one negative-going pulse with each rotation of impeller  35 . 
     Advantageously, upon the application of suction by a user (fluid movement being indicated by the arrow in  FIG. 10 ) the longitudinal play in impeller assembly  30 , i.e., the free longitudinal movement within through-bores  50  and  60  of spindles  72  and  73 , causes each face  74  of plurality of pawl ramps  90  that are arranged in concentric relation to bottom spindle  73  to disengage complementary located faces  64  of plurality of ramped teeth  62  arranged in concentric relation to central through-bore  60  of second bearing-hub  58 . As teeth  62  disengage from pawl ramps  90 , impeller  35  is free to rotate and thereby provide a rate of flow of fluid according to the method described herein above ( FIG. 10 ). However, when suction is removed, i.e., when the user stops drawing fluid from mouthpiece  11  (fluid movement being indicated by the arrow  FIG. 8 ) spindles  72 ,  73  are free to move longitudinally within journals  36  and  38  so as to allow teeth  62  re-engage pawl ramps  90  and thereby prevent further rotation of impeller  35 . In this way, the movement of residual fluid back through housing  31  will not cause impeller  35  to rotate and thereby avoid the generation of false fluid delivery signals. 
     It is to be understood that the invention is by no means limited only to the particular constructions herein disclosed and shown in the drawings, but also comprises any modifications or equivalents within the scope of the claims.