Patent Publication Number: US-2011062367-A1

Title: Valve for Tankless Water Heater

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to liquid shut-off valves and in particular, shut-off valves for use with a tankless water heater. 
     2. Background Art 
     Tankless water heaters are a class of water heaters which have minimal reservoir volume and heat hot water on demand when needed. Tankless water heaters are frequently located near the point of use in order to minimize the volume of water between the water heater and the point of use which typically goes to waste after hot water use is terminated. Further energy savings occurs due to the fact that the water is only heated on demand therefore there is no large hot water reservoir constantly leaking heat to the environment even during long periods of inactivity. 
     Due to the small liquid volume within a tankless hot water heater, it is frequently necessary to periodically drain and flush the tankless water heater to prevent or eliminate scale build up. 
       FIG. 1  illustrates a common plumbing installation for tankless water heater  20  which has a cold water inlet  22  and a hot water outlet  24 . Tankless hot water heater  20  will be provided typically with an internal electric heating element (not shown), heating an internal conduit extending between inlet  22  and outlet  24 . Cold water comes into the system via cold water inlet pipe  26  passing through a first shut off valve  28  which is typically a ¼ turn ball valve having an open and close position. Valve  28  of course can have other valve constructions such as that of a gate valve or the like. Interposed between valve  28  and cold water inlet  22  is a T-branch connection  30  coupled to an auxiliary inlet/outlet valve  32 . Valve  32  is provided with an inlet/outlet  34  which is normally closed by cap  36 . In normal use, valve  28  is open and valve  32  is closed. 
     The hot water outlet  24  of tankless water heater  20  is connected to a hot water outlet pipe  38  by a fluid line having a shut off valve  40  which is preferably, a ¼ turn ball valve, but alternatively, can be a gate valve or the like. Between shut off valve  40  and the hot water outlet, a T-branch connection  42  is provided for mounting an auxiliary shut off valve  44  having an inlet/outlet  46  removably closed by cap  48 . Ideally, a pressure relief valve  50  is provided in the system to let hot water escape in the event an extremely high pressure condition occurs. In normal operation, water flows through tankless water heater  20  in the direction of the in and out arrows illustrated in  FIG. 1 . When one desires to flush the system, valves  28  and  40  are closed and, valves  32  and  44  are opened. Caps  36  and  48  are removed from outlets  34  and  46  so the system may be drained and water or other flushing fluid run through the heater to remove scale build up. While the system of valves illustrated in  FIG. 1  functions satisfactorily, the valves are relatively expensive and occupy a fair amount of space. 
     An object of the present of invention is to make a low cost valve assembly for use with a tankless water heater. It is further an object of the present invention to provide a very compact valve system so that the tankless water heater can be mounted in a tight space. 
     SUMMARY OF THE INVENTION 
     A valve assembly is provided having a valve body formed of at least two sections, each having a tubular passageway portion and when joined together, defining a ball cavity in communication with the tubular passageways. One of the body sections is provided with an inlet/outlet in communication with the ball cavity as well as a spindle flange. An elongate spindle extends through the spindle flange projecting into the ball cavity region. A spherical ball element is oriented within the ball cavity and is rotatably driven by the spindle between an open and a bypass position. The ball valve has a primary elongate passage which interconnects the two tubular passage portions in the valve body sections when the ball valve is in the open position. When the ball valve is rotated to the bypass position, the tubular passage portion of one of the ball body sections is sealed closed while the other tubular passage portion communicates with an internal bypass port within the ball valve which in turn, communicates with the auxiliary inlet/outlet. The preferred embodiment includes a pair of valve assemblies for use with a tankless hot water heater having a cold water inlet and hot water outlet. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration of the prior art installation of a tankless hot water heater; 
         FIG. 2  is a schematic illustration of the valves of the present invention installed in a tankless water heater system; 
         FIG. 3  is a partially cutaway perspective view of an inlet valve assembly of the present invention; 
         FIG. 4  is a partially cutaway perspective view of an outlet valve assembly of the present invention; 
         FIG. 5  is a perspective view of the spherical ball; 
         FIG. 6  is a longitudinal cross-section of the spherical ball; 
         FIG. 7  is a transverse cross-section of the spherical ball; 
         FIG. 8  is a partially cutaway perspective view of the inlet valve assembly in the bypass position; 
         FIG. 9  is a cross-sectional side elevational section view of the inlet valve in the bypass position; 
         FIG. 10  is a partially cutaway perspective view of the outlet valve assembly in the bypass position; 
         FIG. 11  is a cross-sectional side elevational view of the outlet valve assembly in the bypass position; 
         FIG. 12  is a perspective view of the inlet valve assembly illustrating an alternative handle configuration; and 
         FIG. 13  is a perspective view of the outlet valve assembly illustrating an alternative handle configuration. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or as a representative basis for teaching one skilled in the art to utilize the present invention. 
       FIG. 2  illustrates a tankless water heater system  52  which includes a tankless water heater  20  having a water inlet  22  and a hot water outlet  24 . Cold water enters the system through a cold water inlet pipe  26  which is connected to the cold water inlet  22  by an inlet valve assembly  54  of the present invention. Water exiting the tankless hot water heater  20  through outlet  24  passes through outlet valve assembly  56  which is connected to outlet pipe  38 . The single inlet valve and the single outlet valve of the present invention each replace two separate valves and interconnecting plumbing which are shown in  FIG. 1  and described above. The inlet and outlet valves  54  and  56  of the present invention have significantly fewer parts having a single rotary ball and therefore occupy substantially less space than prior art systems. 
     Inlet valve assembly  54  is illustrated in greater detail in  FIGS. 3 ,  8  and  9 . Outlet valve  56  is shown in greater detail in  FIGS. 4 ,  10  and  11 . Referring to  FIG. 3 , inlet valve assembly  54  comprises a valve body formed of at least two body sections, first body section  58  and second body section  60  which respectfully have an elongate tubular passageway portions  62  and  64  extending therethrough. In this preferred embodiment, the elongate tubular passageway portions  62  and  64  are coaxially aligned along a longitudinal axis shown by flow directional arrows in  FIG. 3 . Body sections  58  and  60 , when joined together, define an enclosed ball cavity  66  therebetween, which communicates with elongate tubular passageway portions  62  and  64 . One of the two body sections, in the embodiment illustrated the first body section  58 , is provided with an auxiliary inlet/outlet  68  which communicates with the ball cavity  66 . The first body section further defines a tubular spindle flange  70  which also communicates with ball cavity  66 . 
     The inlet valve assembly  54  is provided with an elongate spindle  72  which is coaxially mounted within spindle flange  70  for limited rotation between an open position shown in  FIG. 3  and a bypass position shown in  FIG. 8 . Spindle  72  has a first end  74  extending into the ball cavity  66  and a second end  76  external from the ball cavity. A generally spherical ball valve  78  is oriented within ball cavity  66  trapped between the first and second body sections  58  and  60 . Ball valve  78  is provided with a notch for receiving a non-cylindrical first end of the spindle  74  therein so that the spindle and ball valve rotate in unison about the spindle axis. The ball valve is provided with a primary elongate passage  80  which extends therethrough which is aligned with first and second tubular passage portions  62  and  64  as shown in  FIG. 3  when the ball valve  66  is oriented in the open position. In the open position, fluid may flow straight through the valve with minimal flow resistance. Annular seals  82  and  84  are oriented in first body sections  58  and  60  at the intersection of a first tubular passage portion  62  and a second tubular passage portion  64  and ball cavity  66 . First and second annular seals  82  and  84  sealingly cooperate with the outer peripheral spherical surface of the ball valve  78  immediately outboard of the primary elongate passageway  80  to provide a fluid tight connection. 
     Spindle  72  is held within tubular spindle flange  70  by a packing gland  86  which threadlingly cooperates with the tubular spindle flange and further cooperates with an O-ring seal  88  at the axial end of the packing gland and a pair of annular spindle seals  90  which fit into machined grooves in the spindle. Preferably, the second end of the spindle  72  has a non-circular outer periphery to cooperate with a similarly shaped non-circular hole in the proximate end of handle  92  so that handle  92  may drivingly rotate spindle  72 . A nut  94  or other suitable threaded fastener removably attaches handle  92  to the second end of the spindle  72  as illustrated in  FIG. 3 . Of course, a bolt cooperating with an internally tapped bore in the in the spindle could alternatively be used as could other conventional methods for attaching a handle to the spindle. 
     In the inlet valve assembly  54  embodiment illustrated in  FIG. 3 , the first body section  68  is removably attached to tankless water heater inlet  22  by a coupling formed by a nut  96  which cooperates with a threaded outer peripheral portion of the first body section  58  as illustrated in  FIG. 3 . A seal  98  interposed between the end of the cold water inlet and the first body section insures a fluid tight seal. Other conventional methods of removably attaching the inlet valve assembly  54  to the hot water heater  20  can be utilized as may well be known to those skilled in the art. For example, a tubular crimp connection can be utilized such as crimp connector  99  shown on the second body section  60  for attaching the inlet valve assembly to cold water inlet pipe  26 . 
     Outlet valve assembly  56  shown in  FIG. 4  is very similar in construction to inlet valve assembly  54  of  FIG. 3 . For the purposes of simplicity, the component parts making up outlet valve assembly  56  are given 100 series reference numbers. The only difference between outlet valve assembly  56  and inlet valve assembly  54  is the addition of a T-connector  102  formed in the first body section  158  and communicating with the first tubular portion  162 . T-connector  102  is intended to provide a compact mounting location for a pressure relief valve  50 . The T-connector  102  is preferably formed with an internal pipe thread for receiving a pressure relief valve  50  having a male threaded connector. Of course, external threads or an alternative coupling system may be employed. 
     Both the inlet valve assembly  54  and outlet valve assembly  56  have a ball valve  78  and  178  of similar construction. A representative one of the ball valve  78  is shown in  FIGS. 5-7 . Ball valve  78  is a generally spherical outer surface  200 . Ball valve  78  is sized to fit within ball cavity  66  for rotation about a spindle axis  202 . One axial end of the ball valve is provided with a notch  204  sized to receiving a non-circular first end  74  of the spindle. Extending centrally through the ball valve aligned along a primary axis  206  perpendicular to the spindle axis  202  is a primary elongate passageway  80 . When ball valve  78  is oriented in the open position as shown in  FIG. 3 , primary elongate passage  80  is coaxially aligned with first and second tubular passage portion  62  and  64 . When the ball valve is in the open position, first and second annular seals  82  and  84  cooperate with the spherical outer surface  200  of the ball valve in the region immediately outboard of primary elongate passage  80 . The primary passageway is also illustrated in  FIG. 6  which is a cross-sectional view taken along a plane parallel to the primary axis  206  and cross-sectional view in  FIG. 7  which is taken along a plane perpendicular to primary axis  208  through the center of the ball valve  78 . 
     Ball valve  78  is further provided with an internal bypass port  208  which the ball valve  78  is rotated to the bypass position as aligned with first tubular passage portion  62 . The internal bypass port is preferably isolated from primary elongate passage  80  allowing fluid to flow through the bypass port into the ball cavity which generally surrounds ball valve  78 . Auxiliary inlet/outlet  68  is coupled to the ball cavity  66 , therefore, when handle  92  and the ball valve  78  are rotated to thy bypass position as shown in  FIG. 8 , first tubular passage portion  62  in the first body section  58 , is coupled to the auxiliary inlet/outlet  68  allowing fluid to freely flow therebetween. In the preferred embodiment, internal bypass port  208  ends in an annular opening sufficiently small to fit within first annular seal  82  so that first annular seal engages outer spherical surface  200  of ball valve  78 . When in the bypass position, second annular seal  84  engages the spherical annular surface of ball valve  78  so that both the first and second annular seals  82  and  84  are maintained in a compressed state. 
     Internal bypass port  208  as previously described, has passageway opening extending orthogonal to spindle axis  202  for communication with first tubular passage portion  62  when ball valve  78  is rotated to the bypass position. Fluid entering the internal bypass port  208  may exit into the ball cavity  66  via axial opening  210 . Alternatively, rather than having two separate discrete openings in the internal bypass port, an elongate channel can be utilized, however, this design is not preferred when elastomeric seals are used since the seals will not be maintained uniformly compressed when the valve is in the bypass position which could result in premature seal failure or increased valve friction. The flow path interconnecting the first tubular passage portion  62  and the auxiliary inlet/outlet  68  when the ball valve is in the bypass position is further shown in  FIGS. 8 and 9 .  FIGS. 9 and 10  illustrate the flow path and outlet valve assembly  56  which from a ball valve function is identical to the inlet valve assembly  54 . 
       FIGS. 12 and 13  are perspective views of the inlet valve assembly and outlet valve assembly  54  and  56  illustrating an alternative handle construction  220  and an alternative fastener bolt  222 .  FIGS. 12 and 13  further illustrate caps  224  and  226  which respectively cooperate with the threaded exterior periphery  228  and  230  of inlet/outlet  68  and  168 . Caps  224  and  226  are preferably connected to the valve assembly by a tether  232  and a collar ring  234  which press fits over threads  228  on the inlet/outlet  68 . Similarly, outlet valve  56  is provided with a tether  236  having a collar ring  238  cooperating with the threaded exterior  230  of auxiliary inlet/outlet  168 . Caps  224  and  226  are pivotally attached to the tether  232  and  236  by a conventional swivel connection. Ideally, caps  224  and  226  are provided with an internal seal  238  and  240  to provide a leak tight fluid connection when the cap is installed in the inlet/outlet. 
     When in use, inlet and outlet valve assemblies  54  and  56  would be normally oriented in the open position allowing water to freely flow therethrough when used in conjunction with a tankless hot water heater. When it is desired to flush the system, the handles and associated ball valves are rotated to the bypass position by rotating the handle a quarter turn about the spindle axis. The tankless water heater  20  is then isolated from both the inlet supply line  26  and the outlet supply line  38 . Caps  224  and  226  are removed from inlet/outlets  68  and  168  and the water within the tankless hot water heater  20  is allowed to drain. If desired, hose couplings can be attached to the inlet/outlet and the system flushed with the water or suitable solvent to scale. 
     While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.