Abstract:
A canister flush valve is disclosed with a valve seat modified to accommodate a greater initial surge of flow, without distorting flushing performance. There is a mounting at the bottom of a toilet tank that links to an outlet hole from the tank and forms a valve seat. A passageway through the mounting tapers in an arcuate manner below the valve seat. There is also a guide support structure in the passageway, preferably centered. The guide support structure also has a tapered leg.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority based on U.S. provisional application 61/043,817 which was filed Apr. 10, 2008. 
    
    
     STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to flush valves that control the flow of water from toilet tanks to toilet bowls. More particularly, the invention relates to a tank valve seat mountable to a toilet tank and preferably used with canister type flush valves. 
     Many systems for controlling the flow of toilet tank water to a toilet bowl are known. Such systems have a water inlet valve connected to the tank that is typically controlled by a float that reacts to the tank water level. Depressing a trip lever or other actuator moves a flush valve at the tank outlet so that water can empty from the tank into the bowl. As the tank water drains, an inlet valve float drops with the water level in the tank, thereby triggering inlet water flow to refill the tank. After sufficient tank water leaves the tank, the flush valve closes so that the water level in the tank can be re-established. As the tank refills after the outlet valve has closed, the supply valve float rises with the water and eventually closes the supply valve to shut off the water supply. 
     A variety of flush valves have been devised for controlling the flow of water from the tank to the bowl. One of the most common is the flapper type flush valve. Flapper flush valves have a pivotal yoke that supports a large diameter stopper that seals off the tank outlet until the trip lever is actuated to start a flush cycle. The large stopper is filled with air that slows the reseating of the stopper until sufficient water has been drained from the tank. On occasion, some such valves have difficulty in completely closing off outlet flow if the flapper doesn&#39;t drop onto the valve seat exactly right. 
     Another type of flush valve has a dedicated float that moves straight vertically upwards once tripped, and then straight vertically downward. See eg. U.S. Pat. Nos. 5,329,647, 5,896,593, 6,715,162, and 6,728,976. 
     A particularly preferred type of flush valve that works in this manner is the canister flush valve shown in U.S. patent application publication 2007/0101485, which is hereby incorporated by reference as if fully set forth herein. However, this type of canister design, when used with its shown valve seat, presents a number of design constraints. 
     For example, to achieve sufficient initial flow one may have to increase the diameter of the entry to the bowl&#39;s rear extension to a point where non-standard fittings are required, and/or aesthetics are affected. Moreover, the flow characteristics may be such as to limit certain water usage efficiencies that must be compensated for otherwise. 
     One complicating factor is that in order to insure vertical movement of the valve body, a guide is positioned on the valve seat. As this is typically at the center of the flow passage through the seat, the guide itself can impede flow and complicate design revisions. While U.S. Pat. No. 5,926,861 proposes to have the guide for the canister be at the periphery of the seat, it requires a relatively complex and expensive structure to implement that proposal. 
     In light of the above, improvements are needed to address these concerns. 
     SUMMARY OF THE INVENTION 
     The present invention covers in one aspect a flush valve for controlling a flow of water out through a hole in a wall of a toilet tank. The flush valve has a mounting having a lower end suitable for facilitating installation of the mounting adjacent the hole, an upper end in a form of a valve seat, and a through passage extending down from the valve seat. It also has a guide portion mounted in the through passage and extending upward there from. 
     There is also a valve body positionable over the valve seat so as to be suitable to inhibit water flow through the mounting when in a first position where the valve body is positioned on the valve seat, and so as to be suitable to permit water flow through the mounting when the valve body is in a second position where the valve body is not positioned on the valve seat. In accordance with the present invention the through passage tapers below the valve seat. 
     In preferred forms the through passage arcuately narrows below the valve seat from a diameter above 2.9 inches to a diameter below 2.3 inches, more preferably below 2.1 inches, the valve body is a canister type valve body, the guide portion has a lower leg structure that tapers arcuately below the valve seat, and the mounting has external threads proximate a lower end of the mounting so as to facilitate installation of the mounting through the tank hole. Alternatively, when a one-piece style toilet is involved with a blind attachment hole, instead of threading the lower end of the structure one can use a bayonet style attachment system like that of U.S. Pat. No. 4,433,446. 
     It will be appreciated that the enlarged valve seat and correspondingly large canister valve produces a large discharge flow rate of water to enter as soon as the canister valve is lifted off the valve seat. The tapering of the passageway below the valve seat (and the corresponding tapering of the guide portion) then permit the flow to be smoothly transitioned to the desired size with no impedance to the developed flow rate. 
     In another aspect the invention provides a mounting useful as part of such a flush valve. That mounting may have a body in the form of a sleeve and have a lower end suitable for facilitating installation of the body adjacent a tank wall outlet hole. The mounting also has an upper end in a form of a valve seat, a through passage extending down from the valve seat, and a guide post mounted in the through passage and extending upward there from. The through passage tapers below the valve seat. 
     It should be noted that the guide post can be centered along the center line of the canister valve body for optimal guiding. This is also a cost effective way of achieving the guiding. However, adequate flow can occur past the guide portion, even in connection with low flush toilets. 
     In another aspect the invention provides a toilet (with tank and bowl), where the above flush valve controls outflow from the tank to the bowl. 
     Hence, the present invention improves the performance of conventional, high performance, canister valves so as to permit an uncompromised discharge flow rate of water to quickly pass into the toilet once flushing has started. This is achieved at relatively low cost, and in a manner that does not require the bowl rear extension to be widened to accommodate the greater flow. 
     These and other advantages of the invention will be apparent from the detailed description and drawings. What follows are one or more preferred embodiments of the present invention. To assess the full scope of the invention the claims should be looked to as the preferred embodiment(s) are not intended as the only embodiment(s) within the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view depicting a flush valve of the present invention installed in a toilet tank of the present invention; 
         FIG. 2  is a top plan view of the  FIG. 1 , with the tank cover removed; 
         FIG. 3  is a perspective view of the  FIG. 1  flush valve; 
         FIG. 4  is an exploded perspective view of the  FIG. 2  flush valve; 
         FIG. 5  is a view similar to  FIG. 4 , but showing the parts from a different angle; 
         FIG. 6  is a sectional view taken along line  6 - 6  of  FIG. 3 ; 
         FIG. 7  is a sectional view taken along line  7 - 7  of  FIG. 3 ; 
         FIG. 8  is an enlarged detail view per arc  8 - 8  of  FIG. 6 ; 
         FIG. 9  is an enlarged top perspective view of a preferred mounting of the present invention; 
         FIG. 10  is a bottom perspective view of the  FIG. 9  mounting; and 
         FIG. 11  is a view similar to  FIG. 6 , but showing the canister valve body raised to a second position off the valve seat. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring first to  FIGS. 1 and 2 , a toilet  10  is shown that includes a water tank  12  and a bowl  14  (partially shown in hidden lines). The tank  12  may be coupled to the bowl  14  using a bracket like that of U.S. Pat. No. 6,728,976. 
     The tank  12  includes a cover  16  and a generally horizontal bottom wall  18  with an outlet opening  20  that leads to a channel in an upper rim (not shown) of the bowl  14 . Mounted inside the tank is the typical water supply pipe  22  with a float  24  operated supply valve  26  for controlling the flow of supply water  28  into the tank  12 . In this regard, when the float drops (as water has exited the tank), water is supplied to the tank. Once the float follows the water back up far enough, the supply water automatically turns off. 
     A flush valve assembly  30  in accordance with the present invention is mounted inside the tank  12  over the outlet opening  20  to control the flow of water  28  out from the tank  12  to the bowl  14  during a flush cycle. A trip lever assembly  31  is coupled to the tank  12  and to a portion of the flush valve assembly  30  and can be triggered to initiate a flush cycle. 
     With additional reference to  FIGS. 3-5 , the flush valve assembly  30  is mounted vertically upright in the tank  12  proximate the bottom wall  18 . The flush valve assembly  30  primarily includes a mounting  32  and a valve body  34  incorporating a seal  36  that moves relative to the mounting  32  generally along a central axis  38  (shown in  FIGS. 2 and 3 ). The mounting  32  and the valve body  34  are preferably constructed of a non-corrosive, chemical resistant material, such as a suitable plastic. The seal  36  can be made of a flexible material, for example a suitable elastomer, such as vinyl, EPDM rubber, or silicon, which has particularly good chemical/corrosion resistance properties. However, one skilled in the art will appreciate the variety of materials suitable for the mounting  32 , valve body  34 , and seal  36 . 
     The mounting  32  is coupled to the tank  12  by a retaining nut  39  that threads onto exterior threads  40  formed proximate the lower portion  42  of the mounting  32  that extends through the tank outlet opening  20 . An annular flange  44  extends radially from the mounting  32  to sandwich a gasket  46  between the bottom wall  18  of the tank  12  and the flange  44  (best shown in  FIG. 1 ). This gasket  46  prevents water  28  from leaking from the tank  12  and, for instance, onto the floor of a bathroom. 
     In one alternate example configuration not shown, the lower portion  42  of the mounting  32  can have three prongs that extend through a trilobular opening and engage the tank  12 . This connection is similar to that disclosed in U.S. Pat. No. 4,433,446, which is assigned to the assignee of the present invention, and the disclosure of which, particularly  FIGS. 2-6  and the related description, is hereby incorporated by reference. 
     With additional reference to  FIGS. 6-11 , the mounting  32  defines a passageway  48  that extends between a valve seat  50  at one end and a valve outlet  52  at the opposite end. The passageway  48  defines a substantially arcuate surface  54  that tapers down from the valve seat  50  toward the valve outlet  52 , as best shown in  FIG. 6 . The arcuate surface  54  may be smooth to minimize impediment to the flow of water  28 . Additionally, the arcuate surface  54  is preferably contoured to mimic the natural flow of water  28  so as to maximize the flow rate of the water  28  from the tank  12  to the bowl  14 . The passageway  48  includes a linear portion  56  proximate the valve outlet  52 ; however, the passageway  48  may be entirely arcuate from the valve seat  50  to the valve outlet  52 . 
     In the preferred example embodiment, the valve seat  50  and the valve outlet  52  are preferably concentric with respect to a central axis  38 . The valve seat  50  is substantially circular and has a valve seat diameter  58  that is greater than a valve outlet diameter  60  (shown in  FIGS. 9 and 10 ). The valve outlet  52  is also substantially circular. 
     In the example embodiment, the valve seat diameter  58  is approximately three inches to allow for a sufficient amount of water  28  to flow both during the initial inrush of a flush cycle and during the balance of the flush cycle. The passageway  48  reduces the larger valve seat diameter  58  to a valve outlet diameter  60  of approximately two inches proximate the valve outlet  52 . As a result, the passageway  48  funnels or directs the water  28  toward the bowl  14 , providing sufficient bowl  14  cleaning and waste removal water  28  during a flush cycle, and to permit coupling the mounting  32  to more traditional components and fixtures. 
     The passageway  48  may take on a variety of arcuate surface configurations of reducing cross section, with each having a goal of efficiently transferring water  28  from the tank  12  to the bowl  14  during a flush cycle. The tapered passageway  48  has the added benefit of making the mounting  32  compatible with standard bowls and other coupling components, while allowing the enhanced flow of water  28 . 
     The mounting  32  includes a series of supports  62  in the form of arcuately tapered legs that extend inward from the passageway  48  and converge proximate the central axis  38  where they define an opening  64 . The supports  62  taper below the valve seat  50  toward the valve outlet  52  to maximize the flow of water  28  through the passageway  48 . The opening  64  is configured to receive a guide portion  66  in the form of a post. The guide portion  66  has a pair of legs  68  formed proximate a lower end  70  that selectively lock into the opening  64  to prevent axial movement of the guide portion  66 . 
     The guide portion  66  also includes upwardly extending tapered gussets  72  that terminate in a hollow upper end  74  that is configured to receive a refill nozzle  76  and stop washer  78  that captures the valve body  34  to the guide portion  66 . During a flush cycle, the refill nozzle  76  receives water  28  from the supply valve  26  via tube  80 . The refill nozzle  76  allows water  28  to fill a portion of the valve body  34  and tank  12  during a flush cycle to influence the duration of the flush cycle and to restore the bowl water to an initial level. 
     The substantially cup-shaped valve body  34  is a type of float that is open to the ambient at a top  35  and includes an exterior wall  85  and an interior tube  86  that generally rides along the guide portion  66  during a flush cycle. The interior tube  86  is substantially conical and tapers toward an upper rim  88  of the tube  86 . The conical configuration of the interior tube  86  acts to center the valve body  34  with respect to the mounting  32  as the valve body  34  sinks from the raised position to the lowered position. Should water  28  breach the upper rim  82  of the valve body  34 , the water  28  begins to fill a circular pocket  84  formed between the interior tube  86  and the exterior wall  85 . The water  28  drains through openings  73  first and then climbs to upper rim  88  of the interior tube  86  if the incoming overflow rate is high enough. Note also gussets  72 . 
     The trip lever assembly  31  includes a chain  98  that is hooked between hole  100  formed in a side tab  102  of the valve body  34  and the trip arm  104 , as a result, actuating the trip lever assembly  31  moves the valve body  34  from the lowered position (shown in  FIG. 6 ) toward the raised position (shown in  FIG. 11 ). 
     With specific reference to  FIGS. 6-8 , when the valve body  34  is in the lowered position, the seal  36  prevents water  28  from leaking from the tank  12  to the bowl  14  proximate a perimeter  96  of the mounting  32 . The typically disk-shaped seal  36  is secured in an annular groove  90  formed proximate the lower end  92  of the valve body  34 . In the preferred example embodiment, the seal  36  at least partially engages a ridge  94  that extends upward from the valve seat  50  proximate the perimeter  96  of the valve seat  50  (shown best in  FIG. 8 ) to help establish a watertight seal between the seal  36  and the valve seat  50 . Furthermore, an annular seal-backing flange  106  is spaced apart from the seal  36  and enhances the operation and sealing of the seal  36 . Additionally, a series of slots  108  are formed in the seal-backing flange  106  to enhance the operation of the valve body  34  during a flush cycle. One skilled in the art will appreciate the variety of configurations available to retain the seal  36  to the valve body  34 . 
     The bleed openings  73 , seal-backing flange  106 , slots  108 , and other additional structures are discussed in U.S. patent application number 2007/0101485 that is assigned to the assignee of the present invention, which is hereby incorporated by reference as if fully set forth herein. 
     Prior to a flush cycle the flush valve is in the rest position shown in  FIGS. 1 ,  3 ,  6 , and  7 , with the valve body  34  and seal  36  seated on the valve seat  50  and a “full” tank  12  of water  28  available. Actuating the trip lever assembly  31  pulls the valve body  34  upwardly a sufficient distance to cause the seal  36  to unseat from the valve seat  50 . When the seal  36  is initially unseated from the valve seat  50 , the flared valve seat  50  portion of the passageway  48  allows the water  28  to flow into the bowl  14  with an initial inrush equivalent to a valve of uniform diameter of valve seat  50 . 
     Through the buoyancy of the valve body  34 , the valve body  34  is moved further toward the raised position shown in  FIG. 11 . The water  28  in the tank  12  continues to flow through the mounting  32  along the arcuate surface  54  of the passageway  48  that mimics the natural flow of water  28  toward the bowl  14 . Additionally, the tapered supports  62  minimize water  28  flow resistance in the passageway  48 . Water  28  and waste in the bowl  14  are evacuated to plumbing waste lines in the usual manner through a trap (not shown). The valve body  34  travels down the guide portion  66  until the seal  36  again seats in the valve seat  50  in conjunction with an engineered bleed rate controlled by openings  73 . The flush cycle completes after the tank  12  is refilled with water  28  sufficient to trip the supply valve  26 . 
     It should be appreciated that preferred embodiments of the invention have been described above. However, many modifications and variations to the preferred embodiments will be apparent to those skilled in the art, which will be within the spirit and scope of the invention. Therefore, the invention should not be limited to the described embodiments. To ascertain the full scope of the invention, the following claims should be referenced. 
     INDUSTRIAL APPLICABILITY 
     The present invention provides improved valves for use in controlling outflow of water from a toilet tank to a toilet bowl, and toilets which incorporate these valves.