Patent Abstract:
A sanitary hydrant comprises an isolated reservoir that can be positioned below a freeze level at the location of installation. A piston within the isolated reservoir is operable to expel, during a downward stroke, stored fluid from the reservoir before actuating a valve that allows fluid to flow from a fluid supply source through the hydrant. On an upward stroke, the piston releases the valve and generates a negative pressure within the reservoir that draws fluid from within the hydrant into the reservoir.

Full Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/301,612 filed Feb. 29, 2016, the entire disclosure which is incorporated by reference herein. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    The present disclosure is generally related to contamination-proof hydrants that, when not in use, employ a self-contained reservoir to store water beneath a freeze line located below the surface of the earth. 
       BACKGROUND OF THE DISCLOSURE 
       [0003]    Sanitary hydrants prevent harmful bacteria, such as  Escherichia coli  ( E. coli ), that may be in the groundwater or surrounding soil from contaminating the water source and/or water exiting the hydrant. Many states and local municipalities have adopted hydrant requirements to prevent such contamination, an example of which may be found in Rule 1057 of the American Society of Sanitary Engineers (ASSE). These requirements have forced municipalities, ranchers, camp sites, and other entities with outdoor operations to use contamination-proof “sanitary” hydrants as opposed to the “non-sanitary” hydrants previously employed to accommodate water delivery needs. 
         [0004]    To prevent freeze-related damage, non-sanitary hydrants known in the art employ weep holes positioned below the frost line to drain water contained within the hydrant after the hydrant is shut off. Weep holes, however, do not always prevent freezing. Due to fluctuations in the degree of water saturation of the ground surrounding the hydrant (which may be caused at least in part due to frequent use of the hydrant), the drain water may not always percolate into the ground before it freezes. In addition, if the groundwater level rises above the weep hole, then groundwater may enter the hydrant through the weep hole. The groundwater may be contaminated. If so, each time the hydrant is turned on, the contaminated water in the operating pipe may mix with the water drawn from the water source, thereby causing spoiled water to be expelled by the hydrant and/or spoilage of the water source. 
         [0005]    To prevent the backflow of water into the non-sanitary hydrant, a check valve is often employed. If, however, the check valve wears out or malfunctions, contaminated water may enter the hydrant, thus endangering crops, livestock, and humans. 
         [0006]    One skilled in the art will appreciate that hydrants employing weep holes open to groundwater may be susceptible to deliberate contamination by a malfeasor, or even to accidental contamination by a careless actor. More specifically, it is easily seen how contaminants placed into the ground could infiltrate into a damaged hydrant and spoil a water supply. In addition, an ancillary problem with non-sanitary hydrants is that contaminated water may affect the food supply. For example, in 2006 an  E. coli  scare occurred in the United States, wherein people became sick or died after they consumed spinach that had been watered and/or cleaned by water from a source that had been polluted by  E. coli . Hydrants that are isolated from the surrounding soil are thus more desirable than those that are open to the surrounding soil, at least because they substantially prevent water spoilage by natural and unnatural sources. 
         [0007]    One way to address this concern is to provide a freezeless sanitary hydrant that does not include a path for water to exit (and therefore does not include a path for contaminated water to enter) the hydrant after shut-off. For example, U.S. Pat. No. 5,246,028 to Vandepas (“Vandepas”), which is incorporated by reference in its entirety herein, discloses a sanitary hydrant that includes an isolated reservoir that contains water below the frost line after the hydrant is shut off. When the hydrant is turned on, water from the reservoir is fed into the operating pipe along with the water from the source. Thus the water that previously drained from the operating pipe (e.g. the portion of the hydrant between the reservoir and the hydrant head) never has a chance to become contaminated. Vandepas employs a venturi that reduces the pressure of the water entering the hydrant, which suctions the stored water from the reservoir to be mixed with the inlet water. Venturi-dependent systems, however, require several parts (which add to the cost of such systems) and are often undesirable because they are difficult to fabricate, install and repair. 
       SUMMARY OF THE DISCLOSURE 
       [0008]    The present disclosure describes a sanitary hydrant that addresses the long felt need in the field of sanitary yard hydrant technology to provide a system that is easier to incorporate, operate, and repair than known hydrants and that prevents both freeze-related damage and contamination. The improved freeze-proof sanitary yard hydrant employs an isolated reservoir below the freeze level. When the hydrant is turned off, water drains from the portions of the hydrant above the reservoir into the reservoir, thus protecting the hydrant from freeze damage. Additionally, hydrants according to the present disclosure employ a piston to evacuate water from the reservoir when the hydrant is turned on, and to draw water into the reservoir from the portions of the hydrant above the freeze level when the hydrant is turned off. These and other features of the hydrants described herein facilitate installation, operation, and repair thereof, while also protecting the hydrant from freeze damage and contamination. 
         [0009]    It is thus one aspect of the present disclosure to provide a hydrant that evacuates water from portions of the hydrant above the freeze level when the hydrant is not in use. 
         [0010]    It is another aspect of the present disclosure to isolate the interior of the hydrant from soil, groundwater, and other contamination sources, so as to provide a sanitary hydrant. 
         [0011]    It is still another aspect of the present disclosure to provide a hydrant that may be installed without difficulty, operated easily, and repaired from above ground level while still installed. 
         [0012]    [Insert Claims Prior to Filing] 
         [0013]    Embodiments of the present disclosure provide a hydrant comprising an upper pipe interconnected to a lower pipe via a reservoir pipe that contains a piston and a housing. A reservoir defined by the inner diameter of the reservoir pipe, an upper surface of the piston and a lower surface of the housing, contains water from an operating pipe, which is positioned within the upper pipe and interconnected to a head of the hydrant, after the hydrant is shut-off. As the hydrant is turned on, the piston is forced downward within the reservoir, such that it pressurizes the water in the reservoir. The stored water then flows out of the reservoir into the operating pipe and out the head of the hydrant. As the piston reaches full stroke, it actuates a valve that allows water to flow from a water supply source through the operating pipe and out the head of the hydrant. The piston is drawn upward as the hydrant is turned off, thus expanding the reservoir and creating suction therein which draws the water from the operating pipe and the hydrant head into the reservoir. That is, the fluid that was flowing through the operating pipe when the hydrant was on is transferred to the reservoir located below the frost line to prevent freezing of the hydrant. One skilled in the art will appreciate that the water within the hydrant never has an opportunity to mix with groundwater, thus contamination of the water exiting the hydrant and/or the water source is prevented. Embodiments of the present disclosure use less moving parts and are easier to manufacture, install, maintain and repair than sanitary hydrants of the prior art. Although water has been indicated as the fluid being transferred, one skilled in the art will appreciate that sanitary hydrants (hereinafter “hydrant”) as outlined herein may be used with any fluid. In addition, although a cylindrical construction has been alluded to, one skilled in the art will appreciate that the pipes that make up the hydrants as shown and described may be of any shape that allows for the flow of a fluid. 
         [0014]    It is another aspect of hydrants according to embodiments of the present disclosure that such hydrants be constructed of commonly used materials and processes. 
         [0015]    Embodiments of the present disclosure employ the head, operating pipe, external construction, etc. as other hydrants known in the art. One major difference is that embodiments of the present disclosure employ at least one movable piston as opposed to a venturi to provide a mechanism that transfers fluid from the reservoir. The housing that defines the upper portion of the reservoir may include at least one valve to facilitate expulsion of the fluid in the reservoir and, conversely, movement of the piston to allow the reservoir to be filled after the hydrant is shut off. 
         [0016]    The Summary of the Disclosure is neither intended nor should it be construed as being representative of the full extent and scope of the present disclosure. That is, these and other aspects and advantages will be apparent from the disclosure of the disclosure(s) described herein. Further, the above-described embodiments, aspects, objectives, and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the disclosure are possible using, alone or in combination, one or more of the features set forth above or described below. Moreover, references made herein to “the present disclosure” or aspects thereof should be understood to mean certain embodiments of the present disclosure and should not necessarily be construed as limiting all embodiments to a particular description. The present disclosure is set forth in various levels of detail in the Summary of the Disclosure as well as in the attached drawings and the Detailed Description of the Disclosure and no limitation as to the scope of the present disclosure is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary of the Disclosure. Additional aspects of the present disclosure will become more readily apparent from the Detail Description, particularly when taken together with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the disclosure and together with the general description of the disclosure given above and the detailed description of the drawings given below, serve to explain the principles of these disclosures. 
           [0018]      FIG. 1  is a cross-sectional elevation view showing a hydrant of one embodiment of the present disclosure; 
           [0019]      FIG. 2  is a detailed view of  FIG. 1  showing hydrant just before it is turned on; 
           [0020]      FIG. 3  is a detailed view of  FIG. 1  showing the hydrant after it is turned on; 
           [0021]      FIG. 4  is a detailed view of  FIG. 1  showing the hydrant just prior to full flow; 
           [0022]      FIG. 5  is a detailed view of  FIG. 1  showing hydrant during full flow; 
           [0023]      FIG. 6  is a detailed view of  FIG. 1  showing the hydrant as it is beginning to close; 
           [0024]      FIG. 7  is a detailed view of  FIG. 1  showing the hydrant as is being closed, wherein fluid is entering a fluid storage reservoir; 
           [0025]      FIG. 8  is a perspective and detailed view of  FIG. 1 ; 
           [0026]      FIG. 9  is a detailed elevation view of  FIG. 1  showing the hydrant head during fluid flow; 
           [0027]      FIG. 10  is a detailed elevation view of  FIG. 1  showing the hydrant head when the hydrant is closed; and 
           [0028]      FIG. 11  is a perspective view of  FIG. 10 . 
       
    
    
       [0029]    To assist in the understanding of one embodiment of the present disclosure the following list of components and associated numbering found in the drawings is provided herein: 
         [0000]    
       
         
               
               
             
               
               
             
           
               
                   
               
               
                 # 
                 Component 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 2 
                 Hydrant 
               
               
                 6 
                 Casing 
               
               
                 10 
                 Fluid pipe 
               
               
                 14 
                 External pipe 
               
               
                 18 
                 Cap 
               
               
                 22 
                 Head 
               
               
                 26 
                 Canister 
               
               
                 30 
                 Frost line 
               
               
                 34 
                 Fluid supply 
               
               
                 38 
                 Knob 
               
               
                 42 
                 Piston head 
               
               
                 46 
                 Outlet 
               
               
                 50 
                 Reservoir 
               
               
                 54 
                 Fitting 
               
               
                 58 
                 Inner surface 
               
               
                 62 
                 O-ring 
               
               
                 66 
                 Fluid inlet 
               
               
                 70 
                 Inlet valve 
               
               
                 78 
                 Floor 
               
               
                 82 
                 Fluid 
               
               
                 84 
                 Sealing plate 
               
               
                 86 
                 Boss 
               
               
                 90 
                 First check valve 
               
               
                 92 
                 Hub 
               
               
                 94 
                 Valve stem 
               
               
                 98 
                 Plunger 
               
               
                 102 
                 Seat 
               
               
                 106 
                 Valve guide 
               
               
                 110 
                 Spring 
               
               
                 114 
                 Wall 
               
               
                 118 
                 Internal wall 
               
               
                 122 
                 Internal wall 
               
               
                 126 
                 Seal 
               
               
                 130 
                 Seal 
               
               
                 134 
                 Air 
               
               
                 138 
                 Lower portion 
               
               
                 142 
                 Inner portion 
               
               
                 146 
                 Fluid channel 
               
               
                 150 
                 Opening 
               
               
                 154 
                 2nd check valve 
               
               
                 158 
                 Seal 
               
               
                 162 
                 Canister end 
               
               
                 166 
                 Screw 
               
               
                 170 
                 Bushing 
               
               
                 174 
                 Nut 
               
               
                 178 
                 Stem screw 
               
               
                 182 
                 Yoke nut 
               
               
                 186 
                 Collar 
               
               
                 190 
                 Fluid inlet opening 
               
               
                 194 
                 Inner annulus 
               
               
                 200 
                 Diverter valve 
               
               
                 204 
                 Fluid outlet opening 
               
               
                 208 
                 Fluid conduit 
               
               
                   
               
             
          
         
       
     
         [0030]    It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the disclosure is not necessarily limited to the particular embodiments illustrated herein. 
       DETAILED DESCRIPTION 
       [0031]      FIG. 1  shows a hydrant  2  of one embodiment of the present disclosure that comprises a casing  6  (also referred to herein as a lower pipe) that supports a fluid pipe  1  (also referred to herein as an inner pipe or operating pipe). The casing  6  may, but need not, be cylindrical. In some embodiments, the fluid pipe  10  is a one-fourth inch Schedule  40  galvanized pipe. Use of a narrow fluid pipe  10  (e.g. a fluid pipe having an inside diameter of one half of an inch or less, or of three eighths of an inch or less, or of one quarter of an inch or less, reduces the amount of fluid contained within the fluid pipe  10  when the hydrant  2  is turned off, and thus reduces the amount of fluid that needs to be stored after shut-off and thus the required volume of the fluid storage reservoir. 
         [0032]    The fluid pipe  10  is positioned within an external pipe  14  (also referred to herein as an upper pipe or an outer pipe) interconnected to the casing  6  by a removable cap  18 . An aperture or opening in the removable cap allows the external pipe  14  to pass through the removable cap  18  and into the casing  6 . The external pipe  14  is interconnected to a hydrant head  22  on one end, and to a canister  26  (also referred to herein as a reservoir pipe) at another end. The canister  26  receives fluid from the head  22  and the fluid pipe  10  after the hydrant  2  is shut off. The canister  26  is positioned beneath the frost line  30  and is interconnected to a fluid supply  34 . 
         [0033]    In operation, the fluid pipe  10  is transitioned downwardly when a knob  38  associated with the head  22  is turned. As the fluid pipe  10  moves, a piston head  42  interconnected to an end of the fluid pipe  10  forces air and water from the canister  26  into the fluid pipe  10 . Further movement of the fluid pipe  10  will open an inlet valve  70  that allows fluid to pass into the fluid pipe  10 . Opening the inlet valve  70  allows fluid stored within the canister  26  and fluid from a fluid supply  34  to flow from an outlet  46  of the head  22 . Turning the knob  38  in the opposite direction closes the hydrant  2  by pulling the fluid pipe  10  upwardly, which closes the inlet valve  70  and opens the canister  26  to create a fluid reservoir  50  that receives fluid from the head  22  and the fluid pipe  10 . After the knob  30  is closed, fluid previously within the head  22  and the fluid pipe  10  drains into and is stored within the fluid reservoir  50  of the canister  26  below the frost line  30 . 
         [0034]    The canister  26  can be removed if the hydrant  2  is not operating correctly, by removing the cap  18  and pulling the external pipe  14  interconnected to the canister  26  from the casing  6 . This feature is desirable as the casing  6  can remain in place, such that no excavation of or around the hydrant is needed. Because the inlet valve  70  of one embodiment is integrated with the canister  26 , the fluid supply  34  must be shut off to make repairs. A new external pipe  14  and interconnected canister  26  can then be inserted into the existing casing  6 , or the damaged components of the existing external pipe  14 , head  22 , or canister  26  can be repaired and replaced within the casing  6 . In other embodiments, the casing  6  may be provided with an automatic shutoff valve that closes when the canister  26  is removed. For example, the automatic shutoff valve may comprise a spring-loaded valve that is held in the open position when the canister  26  is installed, but that springs into the closed position when the canister  26  is removed. In still other embodiments, the inlet valve is connected to the casing  6  and remains fixed when the canister  26  is removed. 
         [0035]      FIGS. 2-8  show the canister  26  and associated components of one embodiment of the present disclosure in detail. Here, the canister  26  includes a fitting  54  interconnected to the external pipe  14 . The canister  26  is interconnected to an inner surface  58  of the casing by way of an o-ring seal  62 , and the canister  26  is slidingly interconnected in the casing  6  to facilitate removal thereof for repair or replacement. The external pipe  14  accommodates the fluid pipe  10  that, along with providing a fluid conduit from the fluid inlet  66  to the head  22 , acts as a control rod for the piston  42  that selectively opens the inlet valve  70 . In operation, which will be described in further detail below, as the piston head  42  is transitioned downwardly by rotation of the knob  38 , fluid within the reservoir  50  is forced out of the canister  26  through the fluid pipe  10  and out of the head  22 . As the hydrant  2  is shut off by counter-rotation of the knob  38 , the piston head  42  moves upwardly, away from the canister floor  78 , thereby creating the reservoir  50  that accepts fluid from within the fluid pipe  10  and the head  22 . In some embodiments, the upward movement of the piston  42  within the canister  26  after the inlet valve  70  has closed creates a vacuum that suctions water from the head  22  and the fluid pipe  10  into the reservoir  50 . 
         [0036]      FIG. 2  shows the canister  6  just before the hydrant knob  38  is turned to open the hydrant  2  to fluid flow. Here, the fluid pipe  10  and interconnected piston head  42  are positioned near the fitting  54 . In this configuration, a reservoir  50  is provided that contains fluid  82  that drained from the head  22  and the fluid pipe  10  after the hydrant  2  was previously shut off. A movable sealing plate  84  is positioned within a boss  86  extending from the canister floor  78 . The canister floor  78  also includes a first check valve  90 , which will be described in further detail below. The sealing plate  84  includes a hub  92  interconnected to a valve stem  94 . The valve stem  94  is interconnected to a plunger  98  shown engaged onto a valve seat  102  which closes the hydrant  2  to fluid flow. The valve stem  94  is held in place by a valve guide  106  that allows the valve stem  94  to slide along the longitudinal axis of the hydrant  2 . Fluid pressure acting on lower surfaces of the valve plunger  98  keeps the valve closed. A spring  110  position between the sealing plate  84  and a wall  114  of the canister floor  78  prevents the sealing plate  84  from undesired downward movement, which would unseat the valve plunger  98  and allow water to enter the canister  26 . The spring  110  of one embodiment of the present disclosure is a wave spring. 
         [0037]      FIG. 3  shows the canister  26  configuration just after the knob  38  is turned to open the hydrant to fluid flow, but before full flow. To initiate full flow, it is necessary to exert a downward force on the sealing plate  84  with the piston  42 , so as to unseat the valve plunger  98  and allow water from the fluid supply  34  to enter the hydrant  2 . As the piston  42  transitions downwardly within the canister  26  along Arrow A, the piston head  42  will exert pressure on the stored fluid  82  in the reservoir  50  and expel the fluid  82  upwardly through the fluid pipe  10  and the hydrant head  22 . During this downward movement and before the piston  42  reaches the canister floor  78 , the valve plunger  98  stays engaged onto the valve seat  102 , preventing fluid flow from the inlet  66  into the hydrant  2 . The piston head  42  includes an internal wall  118  that selectively cooperates with the boss  86  before the sealing plate  84  is contacted, which will be described in further detail below. The piston head  42  also engages an internal wall  122  of the canister  26  by way of an o-ring seal  126 , one of the few “dynamic seals” (e.g. seals between system components that move relative to each other) of the system. 
         [0038]      FIG. 4  shows the final moments of canister fluid evacuation. The internal wall  118  of the piston  42  will eventually contact a seal  130  associated with the floor boss  86 . Here, the reservoir  50  is substantially drained and air  134  resides over the piston head  42 . But fluid  82  still resides within a lower portion  138  of the reservoir which must be expelled. In addition, at this stage the plunger  98  remains engaged to the valve seat  102 .  FIG. 4  also shows an inner portion  142  of the piston head  42  contacting the sealing plate  84 . As the piston head  42  moves further down, the inner portion  142  will force the sealing plate  84  downwardly to compress the spring  110  and force the plunger  98  from the seat  102  to open the inlet valve. 
         [0039]      FIG. 4  also illustrates how the first check valve  90  works. When the piston head moves downwardly, the remaining fluid  82  within the lower portion  138  of the reservoir is expelled through the first check valve  90  integrated into the canister floor  78 . The first check valve  90  is a one-way check valve, so fluid can only flow in the direction of Arrow B through the fluid channel  146  provided between the piston head  42  and the floor  78 . Fluid within the fluid channel  146  moves through the wall  114  by traveling through at least one opening  160  (see  FIG. 8 ). 
         [0040]      FIG. 5  shows the hydrant at full flow. In this configuration, the piston head  42  is engaged with the canister floor  78 . More importantly, the inner portion  142  of the piston head  42  has transitioned the sealing plate  84  and the integrated hub  92 , which is associated with the plunger  98  or valve stem  94 , downwardly to open the inlet valve  70 . 
         [0041]      FIG. 6  shows the hydrant  2  as the knob  38  is being closed. As will be understood further upon review of  FIGS. 9-11 , closing the knob  38  will move the fluid pipe  10  and interconnected piston head  42  upwardly along Arrow C. One of ordinary skill in the art will appreciate that pulling the piston head  42  from the floor  78  may produce negative pressure between the piston head  42  and the floor  78 , which may make movement of the piston head  42  difficult. In addition, air pressure within the canister  26  and the annulus between the fluid pipe  10  and the external pipe  14  may adversely affect piston head  42  movement. To ensure the piston head  42  can move upwardly, a second check valve  154  is provided to allow air  134  to move in the direction of Arrow D from above the piston head  42  to below the piston head  42 . The second check valve  154  does not allow fluid or air to move into the canister as the piston head moves downwardly. Additionally, the second check valve  154  may be calibrated to open only when the pressure on one side of the valve differs from the pressure on the other side of the valve by a certain amount that is exceeded when the piston  42  is initially lifted off of the canister floor  78  (e.g. before water from the fluid pipe  10  and the hydrant head  22  can fill the space between the piston  42  and the canister floor  78  to equalize the pressure), but that is not exceeded after the piston  42  reaches a height sufficient to break the seal between the internal wall  118  and the seal  130 , such that water from the fluid pipe  10  and the hydrant head  22  can drain into the reservoir  50  to equalize or reduce the difference between the pressures above and below the second check valve  154 . Those of skill the art will appreciate that other methods of breaking the vacuum may be employed without departing from the scope of the disclosure. 
         [0042]    In the configuration of  FIG. 6 , the first check valve  90  is closed. Movement of the piston  42  upwardly also allows the spring  110  to relax and to push the sealing plate  84  away from the canister floor  78 , which allows the valve plunger  98  to move upwardly into engagement with the valve seat  102  to close the inlet valve  70 . 
         [0043]    As the internal wall  118  is pulled from the boss, fluid within the hydrant head and the fluid pipe  10  can flow into the reservoir  50  as shown in  FIG. 7 . The first check valve  90  is not opened by this action as the fluid pressure within the reservoir  50  is not as great as it is in  FIG. 4  where fluid is being squeezed through the first check valve  90  at high pressure. Again, air (or water, to the extent water has escaped into the portion of the canister  26  above the piston  42 ) can move through the second check valve  154  and under the piston head  42  as the negative pressure created by the moving piston head  42  does open the second check valve. However, second check valve  154  does not fully equalize the pressures above and below the piston head  42  as the piston head  42  transitions upwardly, and the negative pressure within the reservoir  50  is great enough to suction the fluid from the head and the fluid pipe  10 . In this fashion, the reservoir  50  is filled quickly as the piston head  42  is moved upwardly. 
         [0044]      FIG. 8  is a perspective view showing the components of one embodiment of the present disclosure. Here, the way the spring  110  interacts with the sealing plate  84  can be understood. In addition, the hub  92  is interconnected to the upper end of the valve stem  94  and is also interconnected to the sealing plate  84 .  FIG. 8  further illustrates the features of the hydrant  2  that allow removal of the canister  26 . That is, the canister  26  is slidingly interconnected to the fluid inlet  66  by way of at least one of o-ring seal  158 . After removal of the cap  18  interconnected to the casing, as shown in  FIG. 1 , the canister  26  may be pulled from the casing  6  by moving the external pipe  14  upwardly. As external pipe  14  houses the fluid pipe  10  and is interconnected to the canister  26 , pulling the external pipe  14  from the casing  6  will disengage a canister end  162  from the inlet  66 , such that the entire assemblage may be removed. 
         [0045]    Following removal of a canister  26  in the manner described above, installation of a new or repaired canister  26  may be accomplished by interconnecting the new or repaired canister  26  to the external pipe  14 , slidingly inserting the new or repaired canister  26  and the external pipe  14  into the casing  6  until the canister end  162  (with the at least one seal  158 ) engages the inlet  66 , and replacing the cap  18 . 
         [0046]      FIGS. 9-11  show the inner workings of the head  22  of one embodiment of the present disclosure. The knob  38  is operatively associated with a bushing  170  interconnected to the head  22  by way of a nut  174 . The knob  38  is also interconnected to a stem screw  178  by way of a screw  166 . The stem screw  178  has a plurality of threads engaged with corresponding threads in a yoke nut  182 , wherein rotation of the stem screw  178  will move the yoke nut  182  along a longitudinal axis of the hydrant. The yoke nut  182  is interconnected to the fluid pipe  10  by way of a collar  186 , wherein movement of the yoke nut  182  initiated by rotation of the stem screw  178  will selectively open and close the hydrant  2  to fluid flow. 
         [0047]      FIG. 9  shows the configuration of the head during full fluid flow. Here, the yoke nut  182  has been moved downwardly to force the fluid pipe  10  downwardly as described above. The downward motion of the yoke nut  182  is initiated by rotation of the stem screw  178 . As shown, fluid flows through the fluid pipe  10  through the yoke nut  182  and out of a fluid inlet opening  190  provided in the yoke nut. Fluid flows from the fluid inlet opening  190  into an inner annulus  194  provided between the stem screw  178 /yoke nut  182  and the inner surface of the head  22 . Fluid then flows from the inner annulus  194  through the fluid conduit  208  and through the hydrant outlet  46 . 
         [0048]    Because there is a volume of air within the canister and the fluid pipe  10  which must be displaced to allow fluid to flow, some embodiments of the present disclosure employ a diverter valve  200 . In operation, the diverter valve is normally open, which allows air within the fluid pipe  10 , inner annulus  194 , and other portions of the head  22  to be expelled before fluid enters the head  22 . Pressure within the head  22  will increase as fluid enters, which will cause the diverter valve  200  to close wherein fluid is provided only one exit, that being the outlet  46  of the hydrant  2 . Diverter valves  200  of this type are well known and should be understood by those of skill the art. 
         [0049]      FIGS. 10 and 11  show the configuration of the head  22  after the inlet valve  70  is closed. Here, the knob  38  (not shown in  FIG. 10 ) and stem screw  178  have been turned in such a way as to draw the yoke nut  182  upwardly towards the knob  138 . As described above, this process will draw the fluid pipe  10  upwardly, thereby closing the inlet valve  70  and ceasing fluid flow out of the hydrant outlet  46 . Accordingly, fluid within the head  22  and the fluid pipe  10  can now drain into the canister  26  and be stored in the reservoir  50  created between the piston head  42  and the canister floor  78  in the canister  26 . 
         [0050]      FIG. 11  specifically shows that when the yoke nut  182  is drawn upwardly, a fluid outlet opening  204  of the yoke nut  182  is exposed. The fluid outlet opening  204  creates a path from the head  22  through the yoke nut  182 , between the inner surface of the yoke nut  182  and the stem screw  178 , and into the fluid pipe  10 . When fluid flows from the head  22 , the diverter valve  200  is closed. However, draining water from the head  22  into the fluid pipe  10  creates a negative pressure in the head  22  which is accommodated by automatically opening the diverter valve  200  to allow air into the head  22 . The diverter valve  200  remains opened until the hydrant  2  is next opened to fluid flow. 
         [0051]    Although the embodiment described above utilizes a knob  38  interconnected to a stem screw  178  to raise and lower the fluid pipe  10 , other embodiments of the present disclosure may use different lifting mechanisms to raise and lower the fluid pipe  10 . Any suitable lifting mechanism may be used, including, for example and without limitation, lifting mechanisms that utilize one or more levers, gears, pulleys, or cranks. For example, in some embodiments, the fluid pipe  10  is interconnected via a piston rod to one end of a lever rotatably mounted to the head  22  above the inner annulus  194 . The free end of the lever can then be raised to push the piston rod—and therefore the fluid pipe  10  and the piston head  42 —down and turn on the hydrant  2 . The free end of the lever can be lowered to pull the piston rod—and therefore the fluid pipe  10  and the piston head  42 —up and turn off the hydrant  2 . In another embodiment, an upper end of the fluid pipe  10  may be interconnected to a vertically oriented rack (e.g. a linear gear), which may engage and/or be engaged by a pinion (e.g. a circular gear) mounted on or in the head  22 . The pinion may be interconnected to a crank, rotation of which in a first direction causes the fluid pipe  10  to move up, thus raising the piston head  42  and turning off the hydrant, and rotation of which in a second direction causes the fluid pipe  10  to move down, thus lowering the piston head  42  and turning on the hydrant. 
         [0052]    While various embodiments of the present disclosure have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. It is to be expressly understood that such modifications and alterations are within the scope and spirit of the present disclosure, as set forth in the following claims. Further, it is to be understood that the disclosure(s) described herein is not limited in its application to the details of construction and the arrangement of components set forth in the preceding description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Technology Classification (CPC): 4