Abstract:
A fluid-handling device, such as a lawn-and-garden water sprayer, includes a plurality of elastic bladders that are filled via a common manifold. To ensure that all the bladders can be filled without one bladder over expanding or emptying into another one, the fluid-handling device includes a plurality of limit valves in one-to-one correspondence with the plurality of bladders. When filling the bladders, the limit valves are open to convey fluid from the manifold to the bladders. In some examples of the invention, each individual limit valve will close automatically in response to its respective bladder having reached a predetermined expanded length.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of provisional patent application Ser. No. 61/007,285, filed Dec. 12, 2007 by the present inventor. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The subject invention generally pertains to fluid-handling devices (e.g., water sprayers) and more specifically to a device that uses a resiliently expandable bladder. 
       BACKGROUND OF RELATED ART 
       [0003]    Various devices include resiliently expandable bladders for dispensing pressurized water. Examples of such devices are disclosed in U.S. Pat. Nos. 6,659,366; 5,174,477; 4,867,208; 4,735,239 and 3,848,808. These patents show and describe single-bladder devices with limited water-holding capacity. 
         [0004]    Larger bladders can be used for holding greater volumes of water; however, for a given bladder wall thickness, larger diameter bladders tend to have less pressure containing capacity. 
         [0005]    If multiple smaller diameter bladders were interconnected, another problem arises. When two elastic bladders, for instance, are connected to each other by a common conduit, often the less-filled bladder tends to empty into the one that is more full. If additional water is forced into the two bladders, the larger one might actually burst before the smaller one gets even close to being full. 
       SUMMARY OF THE INVENTION 
       [0006]    It is an object of some embodiments of the present invention to provide a fluid-handling device that includes a plurality of elastic bladders connected to a common manifold, wherein the fluid-handling device includes one or more limit valves that ensures that all the bladders can be filled without overfilling any of them. 
         [0007]    Another object of some embodiments is to prevent the normal operating pressure of one bladder from precluding another bladder from reaching its initial bulge state. 
         [0008]    Another object of some embodiments is to provide a backpack system that includes a plurality of elastic bladders for greater volume holding capacity for a given pressure. 
         [0009]    Another object of some embodiments is to provide a multi-bladder system with a limit valve that can be used for both filling and discharging fluid. 
         [0010]    Another object of some embodiments is to provide fluid-handling device that includes a resiliently expandable bladder with a limit valve that prevents the bladder from being overfilled. The limit valve is actuated by a pulling action, rather than a pushing action, so that the valve and actuator can be completely contained within the interior of the fluid-handling device rather than be exposed on the exterior of the device. 
         [0011]    Another object of some embodiments is to limit the expansion of a resiliently expandable bladder that has a normal operating range of expansion (e.g., 20% to 50% of is maximum burst volume) wherein the normal operating pressure is substantially constant over that normal operating range, the normal operating range lies between an initial bulge pressure and a burst pressure, and the normal operating pressure is appreciably less than both the initial bulge pressure and the burst pressure. 
         [0012]    Another object of some embodiments is to limit the expansion of a resiliently expandable bladder by actuating a valve in response to the bladder&#39;s change in axial length. 
         [0013]    One or more of these and/or other objects of the invention are provided by a fluid-handling device that includes a plurality of elastic bladders that can be filled via a common manifold. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a schematic side view of one example of a fluid-handling device. 
           [0015]      FIG. 2  is side view of the fluid-handling device of  FIG. 1  but showing the device installed in a backpack. 
           [0016]      FIG. 3  is a side view of the watering device&#39;s resiliently expandable bladder in a relaxed state. 
           [0017]      FIG. 4  is a side view similar to  FIG. 3  but showing the bladder expanding under an initial bulge pressure. 
           [0018]      FIG. 5  is a side view similar to  FIGS. 3 and 4  but showing the bladder beyond its initial bulge state. 
           [0019]      FIG. 6  is a side view similar to  FIGS. 3-5  but showing the bladder at a predetermined expanded state. 
           [0020]      FIG. 7  is a side view similar to  FIGS. 3-6  but showing the bladder at an over expanded state. 
           [0021]      FIG. 8  is a graph showing the pressure/volume relationship of the bladder of  FIGS. 3-7 . 
           [0022]      FIG. 9  is a cross-sectional side view of the fluid-handling device of  FIG. 1 . 
           [0023]      FIG. 10  is a cross-sectional side view similar to  FIG. 9  but showing an alternate fluid-handling device. 
           [0024]      FIG. 11  is a schematic side view similar to  FIG. 1  but showing another example of a fluid-handling device. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]      FIG. 1  is a schematic diagram showing one example of a fluid-handling device  10  (e.g., water and/or chemical sprayer) for discharging a fluid  14  under pressure. To store and later release fluid  14  under pressure, device  10  preferably includes at least two elastic bladders  16  that are resiliently expandable. To convey fluid  14  to and from bladders  16 , device  10  also includes a manifold  18  connected in fluid communication with both bladders  16 . Bladders  16  can expand resiliently upon receiving fluid  14  under pressure from a suitable source, such as, for example, water from a municipal water supply. 
         [0026]      FIG. 2  shows device  10  connected to a conventional garden nozzle  20  with bladders  16  being installed within a backpack  22  that has two shoulder straps  24 . In this particular example, nozzle  20  not only provides a way to spray fluid  14  discharged from within bladders  16 , but nozzle  20  can be provided with a standard threaded garden hose end  26  that a standard female-to-female garden hose adaptor  28  can connect to a standard garden hose  30  for filling bladders  16 . 
         [0027]    Although bladders  16  can be of various shapes, sizes, construction, and materials, one example of bladder  16  is a latex rubber tube having a relaxed outside diameter of 0.875 inches, a relaxed inside diameter of 0.5 inches, and a relaxed length of 9 inches. 
         [0028]    If a bladder  16  were unprotected from overfilling, bladder  16  could be expanded through the sequential steps shown in  FIGS. 3-7 . The sequence of expansion is also represented in graph  32  of  FIG. 8 , where points  33 ,  34 ,  35 ,  36  and  37  correspond to  FIGS. 3 ,  4 ,  5 ,  6  and  7  respectively.  FIG. 3  and point  33  of  FIG. 8  represent bladder  16  being in a relaxed state with a minimum bladder length  38 .  FIG. 4  and point  34  represent bladder  16  initially bulging at an initial bulge pressure. For a latex tube having a relaxed OD of about 0.875 inches and a relaxed ID of about 0.5 inches, the initial bulge pressure is about 25 psig.  FIG. 5  and point  35  represent bladder  16  expanding beyond the initial bulge of  FIG. 4 .  FIG. 6  and point  36  represent bladder  16  expanding even farther. For bladder  16  with its given sample dimensions, the expansion from point  35  to point  36  occurs at about 15 psig (substantially constant pressure).  FIG. 7  and point  37  of  FIG. 8  represent bladder  16  expanding to its impending burst condition, which for this example occurs at about 25 psig. 
         [0029]    To avoid the impending burst condition and to enable the filling of both bladders  16  through a commonly shared manifold  18 , device  10  includes a limit valve  40  that, with respect to fluid flow, is between manifold  18  and each bladder  18 . Each limit valve  40  allows the filling of its respective bladder  16 ; however, once a bladder  16  reaches a predetermined expanded state ( FIG. 6  and point  36  of  FIG. 8 ), limit valve  40  automatically closes to prevent overfilling of the limit valve&#39;s associated bladder  16 . To achieve such function, device  10  and limit valve  40  can be of various designs, such as, for example, the design shown in  FIG. 9 . 
         [0030]    In  FIG. 9 , manifold  18  includes ends  18   a  and  18   b  that are press fitted into the inner diameter of bladders  16 . Each bladder assembly includes an annular valve seat  42  preferably made of a polymeric material and a helical tension spring  44  that are press fitted into the inner diameter of ends  18   a  and  18   b . A metal ferrule  46  radially crimped inward helps hold bladders  16 , ends  18   a  and  18   b , valve seat  42  and spring  44  in place. A metal screw  48  with a beveled head  50  serves as a valve plug and valve stem, with head  50  being the valve plug and the threaded shank of screw  48  being the valve stem. Head  50  is disposed in proximity with valve seat  42 , and a distal end  52  of screw  48  connects to one end  54  of spring  44  such that spring  44  tends to urge head  50  away from valve seat  42 , thus limit valve  40  is normally open as shown in  FIG. 9 . 
         [0031]    To close limit valve  40 , a flexible and elongate actuator  56  (e.g., string, wire, chain, cable, elastic or inelastic cord, slender rod, slender tube, etcetera, and various combinations thereof) connects screw  48  (via end  54  of spring  44 ) to an anchor  58  at a back end of bladder  16 . In this example, anchor  58  is a neoprene cylindrical plug that is press fitted into an open end of bladder  16  or otherwise affixed bladder  16 . A second metal ferrule  46  radially crimped inward can help hold anchor  58  in place and help maintain a tight seal between anchor  58  and bladder  16 . 
         [0032]    When both bladders  16  are in a relaxed state ( FIG. 3  and the lower bladder of  FIG. 9  illustrates a bladder in a relaxed state), both limit valves  40  are open and pressurized fluid  14  from manifold  18  can possibly flow into either bladder  16 . The bladder  16  having the lowest initial bulge pressure (point  34  of  FIG. 8 ), however, will tend to be the first to expand. For the example of  FIG. 9 , that happens to be the upper bladder  16 . The terms, “upper bladder” and “lower bladder” are in relation to the bladder&#39;s location on the drawing figure and are simply used to distinguish between the two substantially equivalent bladders  16 . As upper bladder  16  expands beyond its initial bulge volume ( FIG. 4 ) to a greater operating volume (e.g.,  FIG. 5  or between points  35  and  36  of  FIG. 8 ) the pressure within upper bladder  16  will decrease from its initial bulge pressure (e.g., 25 psig) to a significantly lower normal operating pressure  60  (e.g., 15 psig). The relatively low operating pressure within upper bladder  16  will tend to reduce the pressure within manifold  18 , thus the resulting reduced pressure in manifold  18  might be insufficient to cause initial bulging of lower bladder  16 . As a result, upper bladder  16  continues to expand, while lower bladder  16  remains at its relaxed state. 
         [0033]    As fluid  14  continues to fill upper bladder  16 , the upper bladder&#39;s lengthwise expansion pulls actuator  56  until actuator  56  reaches its maximum actuator length  62 , wherein actuator  56  is in a taut state as shown in the upper bladder of  FIG. 9 , which corresponds to  FIG. 6 . In the taut state, actuator  56  stretches spring  44  and pulls head  50  of screw  48  to a closed position against valve seat  42  to obstruct additional fluid  14  from flowing into upper bladder  16  and thus substantially inhibiting bladder  16  from expanding beyond its predetermined expanded state of  FIG. 6 . 
         [0034]    With limit valve  40  of upper bladder  16  closed and lower bladder  16  not yet expanding, the fluid pressure within manifold  18  is free to rise due to lack of flow through manifold  18 . Once the fluid pressure in manifold  18  exceeds the initial bulge pressure of lower bladder  16 , lower bladder  16  will expand from it relaxed state ( FIG. 3 ), through its initial bulge state ( FIG. 4 ), and to its predetermined expanded state ( FIG. 6 ). When lower bladder  16  reaches its predetermined expanded state, the lower bladder&#39;s actuator  56  will pull its limit valve  40  closed to prevent overfilling of the lower bladder  16 . At this point, both bladders  16  are full, and both limit valves  40  are closed to prevent overfilling of bladders  16 . 
         [0035]    To later move each head  50  and valve  40  to the open position and release fluid  14  from within bladders  16 , garden nozzle  20  is disconnected from garden hose  30  (or other source of fluid pressure) and garden nozzle  20  is manually opened to release fluid  14  from within manifold  18 . As the pressure within manifold  18  becomes less than the pressure within bladders  16 , the lengthwise resilience or “springyness” of bladders  16  allows some relative movement between head  50  and seat  42  to release some initial fluid out from within bladders  16 . As this initial fluid discharges from device  10 , bladders  16  begin retracting, which loosens actuator  56  to a looser state to fully open limit valves  40 . In this example of the invention, actuator  56  being in a looser state means that actuator  56  is limp or at least not as stressed as when actuator  56  has limit valve  40  pulled to its closed position. In this example, actuator  56  has a maximum actuator length  62  ( FIG. 9 ) that is greater than the minimum bladder length  38  ( FIGS. 3 and 9 ). Also in this example, limit valve  40  is a fill-and-discharge limit valve that conveys fluid  14  into bladder  16  as bladder  16  goes form its relaxed state ( FIG. 3 ) to its predetermined expanded state ( FIG. 6 ) and discharges fluid  14  from bladder  16  as bladder  16  goes from its predetermined expanded state to its relaxed state. 
         [0036]      FIG. 10  shows an alternate fluid-handling device  64  with different limit valves  66 . Device  64  includes ferrules  46  that help hold anchor  58  and a generally rigid valve tube  68  within opposite ends of each bladder  16 . Each valve tube  68  extends through a side hole in a manifold  70  and is bonded, screwed or is otherwise positively attached to a sidewall of manifold  70 . Manifold  70  and valve tubes  68  could also be made as a unitary piece. A cap  72  closes off one end of manifold  70 , and an adaptor  74  couples the other end of manifold  70  to a tube  18 ′, which in turn can be connected to conventional garden nozzle  20  in a manner similar to that of device  10 . In this example, tube  18 ′ can be considered as an extension of manifold  70  and is comparable to manifold  18  in that tube  18 ′ and manifold  18  can both be used to place garden nozzle  20  in fluid communication with bladders  16 . 
         [0037]    Each limit valve  66  includes a resilient tube  76  and a button  78 . Resilient tube  76  has a side hole  80  so that valve tube  68  can protrude upward into the interior of resilient tube  76 . The resilience of tube  76  urges limit valve  66  to its open position, as is the case with limit valve  66  at the right side of  FIG. 10 . Limit valve  66  at the left side of  FIG. 10  is closed. Closing limit valve  66  is by way of a flexible elongate actuator  82  (e.g., string, wire, chain, cable, elastic or inelastic cord, slender rod, slender tube, etcetera, and various combinations thereof) that extends through a small hole  84  in resilient tube  76  and connects button  78  to anchor  58 . 
         [0038]    When both bladders  16  are in a relaxed state ( FIG. 3  and the right bladder of  FIG. 10  illustrates a bladder in a relaxed state), both limit valves  66  are open and pressurized fluid  14  from tube  18 ′ and manifold  70  can possibly flow into either bladder  16 . The bladder  16  having the lowest initial bulge pressure (point  34  of  FIG. 8 ), however, will tend to be the first to expand. For the example of  FIG. 10 , that happens to be the left bladder  16 . The terms, “right” and “left” are in relation to a part&#39;s location on the drawing figure and are simply used to distinguish between two substantially equivalent parts, such as, for example right bladder  16  and left bladder  16 . As left bladder  16  expands beyond its initial bulge volume ( FIG. 4 ) to a greater operating volume (e.g.,  FIG. 5  or between points  35  and  36  of  FIG. 8 ) the pressure within left bladder  16  will decrease from its initial bulge pressure (e.g., 25 psig) to a significantly lower normal operating pressure  60  (e.g., 15 psig). The relatively low operating pressure within left bladder  16  will tend to reduce the pressure within manifold  70 , thus the resulting reduced pressure in manifold  70  might be insufficient to cause initial bulging of right bladder  16 . As a result, left bladder  16  continues to expand, while right bladder  16  remains at its relaxed state. 
         [0039]    As fluid  14  continues to fill left bladder  16 , the left bladder&#39;s lengthwise expansion pulls left actuator  82  until left actuator  82  reaches its maximum actuator length  86 , wherein left actuator  82  is in a taut state as shown in the left bladder of  FIG. 10 , which corresponds to  FIG. 6 . In the taut state, left actuator  82  pulls the left button  78  down, which thus clamps the upper sidewall of left resilient tube  76  down against the upper end of left valve tube  68 , thereby moving left limit valve  66  to its closed position, as shown on the left side of  FIG. 10 . Left valve  66  in the closed position with left button  78  and the left resilient tube  76  blocking off left valve tube  68  stops the fluid flow into left bladder  16  and thus prevents left bladder  16  from expanding beyond its predetermined expanded state. 
         [0040]    With limit valve  66  of left bladder  16  closed and right bladder  16  not yet expanding, the fluid pressure within manifold  70  is free to rise due to lack of flow through tube  18 ′ and manifold  70 . Once the fluid pressure in manifold  70  exceeds the initial bulge pressure of right bladder  16 , right bladder  16  will expand from it relaxed state ( FIG. 3 ), through it initial bulge state ( FIG. 4 ), and to its predetermined expanded state ( FIG. 6 ). When right bladder  16  reaches its predetermined expanded state, the right bladder&#39;s actuator  82  will pull the right limit valve  66  closed to prevent overfilling of right bladder  16 . At this point, both bladders  16  are full, and both limit valves  66  are closed to prevent overfilling of bladders  16 . 
         [0041]    To later move each valve  66  to the open position and release fluid  14  from within bladders  16 , garden nozzle  20  is disconnected from garden hose  30  (or other source of fluid pressure) and garden nozzle  20  is manually opened to release fluid  14  from within tube  18 ′ and manifold  70 . As the pressure within manifold  70  becomes less than the pressure within bladders  16 , the lengthwise resilience or “springyness” of bladders  16  allows some relative movement between button  78  and the upper end of tube  68  to release some initial fluid out from within bladders  16 . As this initial fluid discharges from device  64 , bladders  16  begin retracting, which loosens actuators  82  to a looser state to fully open limit valves  66 . In this example of the invention, actuator  82  being in a looser state means that actuator  82  is limp or at least not as stressed as when actuator  82  has limit valve  66  pulled to its closed position. In this example, actuator  82  has a maximum actuator length  86  ( FIG. 10 ) that is greater than the minimum bladder length  38  ( FIGS. 3 and 10 ). Also in this example, limit valve  66  is a fill-and-discharge limit valve that conveys fluid  14  into bladder  16  as bladder  16  goes form its relaxed state ( FIG. 3 ) to its predetermined expanded state ( FIG. 6 ) and discharges fluid  14  from bladder  16  as bladder  16  goes from its predetermined expanded state to its relaxed state. 
         [0042]    Although the actual construction of device  64  may vary, in some examples resilient tube  76  is made of latex rubber; however, other resilient flexible materials would certainly be well within the scope of the invention. Button  78  can be a disc, rectangle or any shape of sufficient size to obstruct the open end of valve tube  68 . Button  78  can be made of plastic, metal or any material with sufficient rigidity to prevent actuator  82  from pulling button  78  completely through valve tube  68 . As is the case with actuator  56 , actuator  82  can be a string, wire, chain, cable, elastic or inelastic cord, slender rod, slender tube, etcetera, and various combinations thereof. For the example illustrated in  FIG. 10 , actuator  82  includes a stiffer section  82   a  (e.g., aluminum wire) and a more flexible section  82   b  (e.g., nylon string) that are joined end-to-end by tying, crimping or any other suitable means. Stiffer section  82   a  has a stiffer section length  88  that is at least half as long as the relaxed bladder&#39;s minimum bladder length  38 . This helps prevents fluid discharging from within bladder  16  from flushing the more flexible section  82   b  of actuator  82  up and out through limit valve  66 . 
         [0043]      FIG. 11  shows an alternate fluid-handling device  90  comprising upper and lower flow-control valves  92  that connect the upper and lower elastic bladders  16  in fluid communication with manifold  18 . Of course, device  90  could be turned sideways in  FIG. 11 , in which case, valves  92  and bladders  16  would be referred to as right and left components. Each flow-control valve  92  provides an incoming flow restriction  94  to fluid  14  flowing from manifold  18  to bladder  16  and provides an outgoing flow restriction to fluid  14  flowing from elastic bladder  16  to manifold  18 . The incoming flow restriction can be provided by an orifice, capillary, needle valve, etc. and is greater than the outgoing flow restriction. The outgoing flow restriction is merely the pipe losses through tubes  18   a  and  18   b  and/or the nearly free flow through a check valve  96 . The relatively low outgoing flow restriction allows device  90  to spray fluid  14  with minimal flow losses. When filling bladders  16 , the higher incoming flow restriction  94  helps maintain the pressure in manifold  18  relatively high upstream of valves  92 . Thus, the first bladder  16  to expand will not prevent the other bladder  16  from also reaching its initial bulge pressure. 
         [0044]    Although the invention is described with respect to a preferred embodiment, modifications thereto will be apparent to those of ordinary skill in the art. For instance, to improve the connection of adjoining cylindrical parts, it would be well within the scope of the invention to provide cylindrical surfaces of such adjoining parts with conventional barbed ridges. In addition or as an alternative to barbed surfaces, various types of conventional hose clamps can also be used to hold tubular parts together. The number of bladders connected to a common manifold can be one, two, three or any other quantity. To distinguish between similar or identical components, the names of such components can be identified using terms such as, “first,” “second,” “left,” “right,” “upper,” “lower,” etc. The plurality of bladders connected to a common manifold can be substantially equal in size and pressure or the plurality of bladders can differ significantly. The term, “spray nozzle” refers to any fluid discharge device that can release fluid from an elastic bladder and ultimately release the fluid to atmosphere. Examples of a spray nozzle include, but are not limited to, a conventional garden nozzle, a valve, a venturi apparatus, or an eductor cap of a chemical bottle (e.g., U.S. Pat. Nos. 6,578,776; 5,383,603; D451,581 and D358,865). Additional details, background, features and/or advantages of the present invention may be found in U.S. patents issuing from U.S. patent application Ser. Nos. 11/973,167; 11/973,203; and 11/973,166; all of which are specifically incorporated by reference herein. The scope of the invention, therefore, is to be determined by reference to the following claims: