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CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/703,397, filed Sep. 20, 2012, and entitled “Low Head Loss Device for Swimming Pool Heaters or Other Applicable Equipment,” the entire contents of which application are incorporated herein by this reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to flow by-pass systems and assemblies and methods of their use and more particularly, although not necessarily exclusively, to systems and assemblies within manifolds for allowing flowing water to by-pass heat exchangers or other components of swimming pool heaters when such heaters are inactive. 
       BACKGROUND OF THE INVENTION 
       [0003]    U.S. Pat. No. 4,279,128 to Leniger describes an example of a heating system for recirculating water of a swimming pool. The system employs a heat pump to move heat-transfer fluid through primary coils of a heat exchanger while pool water circulates through secondary coils of the heat exchanger. Not all of the circulating pool water passes into the secondary coils, however; instead, some water continues through the circulation system unheated. 
         [0004]    The system of the Leniger patent utilizes both a manually-operable diverter valve to divert pool water toward the heat exchanger and a three-way regulator valve further directing only a portion of the diverted water to the heat exchanger. Designed to maintain relatively constant temperature and pressure of the heat transfer fluid at the exit of the heat pump, the system causes the regulator valve to increase or decrease the amount of pool water passed to the heat exchanger as a function of heat transfer fluid temperature. No other technique of causing all water to by-pass the heat exchanger when the heater is inactive is detailed in the Leniger patent, however, nor is any diverter valve positioned in a heater manifold. 
         [0005]    U.S. Pat. No. 4,398,562 to Saarem, et al., discloses a sample diverter valve for use with swimming pools. The valve, which is motorized, includes a single inlet and two outlets. Two drive motors are mounted on opposite sides of a drive shaft; as the shaft rotates, a diverter member is turned from a first position (connecting the inlet to one outlet) to a second position (connecting the inlet to the second outlet). 
         [0006]    U.S. Pat. No. 6,695,970 to Hornsby details another diverter, or by-pass, valve for recirculating water systems of swimming pools. Included in the valve are both a sliding and a stationary plate, each containing multiple openings. The plates are parallel and abutting; depending on the position of the sliding plate, more or fewer of its openings align with those of the stationary plate to determine water flow through the valve. The entire contents of the Leniger, Saarem, and Hornsby patents are incorporated herein by this reference. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides a low-restriction chamber in a manifold of a heating device. When the heating device is inactive, water may be diverted through the low-restriction chamber for return to a recirculation system (or otherwise) so as to reduce head loss in the flowing water. By redirecting water from an inactive heating device to the low-restriction chamber, less energy may be necessary to circulate the water through the system. Additionally, by avoiding passing water through a heat exchanger when heating is not occurring, less erosion or corrosion of components of the heat exchanger occurs. Positioning the low-restriction chamber and by-pass apparatus within the manifold helps protect them from damage and should result in a less-costly by-pass system, as no separate external plumbing is required. 
         [0008]    In some versions of the invention, present in the low-restriction chamber may be a flow gate. The gate, preferably (although not necessarily) made of lightweight material, may move between at least first and second positions. In the first position, the gate allows substantially-unrestricted flow through the chamber from an inlet to an outlet of the manifold. By contrast, in the second position, the gate diverts water through the heat exchanger of the heating device. The first position thus may be called the “open” position, corresponding if desired to situations in which the heating device is inactive. The second position would then be the “closed” position, appropriate when the heating device is active. 
         [0009]    Any suitable actuator may cause the gate to move between (at least) the first and second positions. A solenoid, servo-motor, or other automatic device is preferably used as the actuator, although manually-operated devices may be used instead in certain instances. Also incorporated into some embodiments of the gate may be a poppet valve assembly. Such an assembly typically exists separate from any diverter valve and is designed to limit the amount of water flowing through the finned tubes of the heat exchanger. In certain versions of the invention, however, the poppet assembly is combined with the gate within the low-restriction chamber. 
         [0010]    It thus is an optional, non-exclusive object of the present invention to provide systems, assemblies, and methods of reducing head loss in heating devices. 
         [0011]    It is an additional optional, non-exclusive object of the present invention to provide heater manifolds or other components with low-restriction chambers. 
         [0012]    It is also an optional, non-exclusive object of the present invention to provide a repositionable gate for directing water flow within a low-restriction chamber, both of which may be placed within a heater housing so as to avoid need for external plumbing. 
         [0013]    It is, moreover, an optional, non-exclusive object of the present invention to provide a repositionable gate with a poppet valve assembly incorporated therein. 
         [0014]    Other objects, features, and advantages of the present invention will be apparent to those skilled in the appropriate art with reference to the remaining text and the drawings of this application. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a cross-sectional, partially-schematic view of an exemplary manifold including technology of the present invention and with a repositionable gate in a “closed” position. 
           [0016]      FIG. 2  is a cross-sectional, partially-schematic view of the manifold of  FIG. 1  with the repositionable gate in an “open” position. 
           [0017]      FIG. 3  is perspective view of an alternative gate of the present invention into which is incorporated a poppet valve assembly. 
           [0018]      FIG. 4  is a perspective view of the gate of  FIG. 3  with the poppet valve assembly exploded. 
           [0019]      FIG. 5  is a perspective view of the manifold of  FIGS. 1-2  to which tubes are attached. 
           [0020]      FIG. 6  is a cross-sectional, partially-schematic view of an exemplary manifold including technology of the present invention and with the repositionable gate of  FIG. 3  in a “closed” position. 
           [0021]      FIG. 7  is a cross-sectional, partially-schematic view of the manifold of  FIG. 6  with the repositionable gate of  FIG. 3  in an “open” position. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Illustrated in  FIGS. 1-2 and 5  is exemplary manifold  10 . Manifold  10  may include at least one inlet  14  and at least one outlet  18 . Also shown in  FIGS. 1-2 and 5  is optional second inlet  22 . Depending on how manifold  10  is plumbed in a water circulation system, either of inlets  14  or  22  may be connected so as to receive circulating water. Typically the other of inlets  14  or  22  would be plugged, although conceivably both inlets  14  and  22  could be used simultaneously. 
         [0023]    Included in manifold  10  may be plural openings  26  and  30 . Openings  26  preferably, although not necessarily, are aligned, as preferably are openings  30 . A corresponding set of openings  26  and  30  may function as inlet and outlet of an associated tube  34  of a heat exchanger or similar device.  FIG. 5  shows six such tubes  34 , although more or fewer tubes  34 , or “tubes” of different shape, may be utilized instead. Also included in manifold  10  may be poppet valve assembly  36 . 
         [0024]    Shown especially in  FIG. 2  is low-restriction chamber  38  within manifold  10 . Chamber  38  preferably is sized and shaped so as to provide substantial volume through which water may flow. Accordingly, if water is not obstructed as it travels from inlet  14  or  22  through chamber  38  to outlet  18 , head loss of the flowing water is anticipated to be minimal--or at least materially less than with current manifold designs. 
         [0025]      FIG. 2  illustrates a barrier, in the form of gate  42 , in its “open,” or second, position. In this position gate  42  does not materially obstruct water flow through chamber  38 . Gate  42  advantageously may be in this open position when a heating device connected to manifold  10  is inactive, resulting in a low-resistance water path existing through the chamber  38 . Little or no water hence enters tubes  34  when no water heating is occurring, reducing wear of the tubes  34  otherwise caused by the flowing water. 
         [0026]      FIG. 1 , by contrast, details gate  42  in its “closed,” or first, position. In this position gate  42  obstructs substantially all water flow through chamber  38 . Water entering manifold  10  through an inlet  14  or  22  hence is directed to openings  26  and into tubes  34  for heating. Heated water returns to manifold  10  through openings  30  and travels to outlet  18  to continue the circulation process. Excess pressure of water entering manifold  10  in this instance may cause poppet valve assembly  36  to open, hence creating a second flow path to outlet  18 . 
         [0027]    Repositioning of gate  42  may be caused by any appropriate device. Preferably gate  42  is actuated by a solenoid configured to turn axle  46  which is connected to the gate  42 . Rotation of axle  46  in turn causes gate  42  to pivot between (at least) its first and second positions. Persons skilled in the art will recognize that gate  42  may move in other manners, or actuated by other devices, instead though. 
         [0028]    Gate  42  beneficially may have a solid face  50  sized and shaped to prevent passage of water when in the closed position (i.e. the area of face  50  is approximately the same as a cross-sectional area of at least some portion of chamber  38 ).  FIGS. 3-4  depict an alternate gate  42 A in which otherwise-solid face  50 A includes an opening  54 . Placed behind opening  54  may be poppet valve assembly  58  including disc  62 , stem  66 , and coil spring  70 . Spring  70  biases disc  62  so as normally to close opening  54 , thus normally causing face  50 A to obstruct flowing fluid it encounters. Should water flow through inlet  14  or  22  exert against face  50 A a force exceeding a predetermined amount, however, it will overcome force of spring  70  and push disc  62  away from opening  54 . This action produces a bypass path into and through chamber  38  to outlet  18  and serves to regulate flow rate into the heat exchanger. 
         [0029]    Incorporating poppet valve assembly  58  into gate  42  avoids any need for the separate poppet valve assembly  36  appearing in  FIGS. 1-2 . Such a modified manifold  10 ′ is depicted in  FIGS. 6-7 , in which gate  42 A is shown in “closed” and “open” positions, respectively. Clear from  FIGS. 7-8  is that, because gate  42 A already includes poppet valve assembly  58 , no separate assembly  38  is needed. 
         [0030]    The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of the present invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of the invention.

Summary:
Low head loss systems are detailed. The systems may include chambers having low impedance to water flow therethrough and repositionable gates or other valves within the chambers. The valves may direct water as a function of whether an associated heating device is active. At least some gates may incorporate poppet valves or other high-flow by-passes.