Abstract:
Apparatus for automatically shutting off the water supply to a leaking water heater includes a water collecting tray positionable beneath the heater, a valve mechanism attachable to the tray, a float mechanism, and an action arm interactive between the float mechanism and valve mechanism. When water collects in the tray, the float mechanism rises, causing the action arm to trigger the release of a spring-urged component of the valve mechanism to discontinue flow of water to the heater.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to apparatus for preventing flooding as a result of leakage from a water heater located in a building, and more particularly concerns apparatus for detecting such leakage and shutting off water flow to the leaking water heater. 
   2. Description of the Prior Art 
   Water heaters, whether in residential or commercial buildings, are susceptible to failure in a manner wherein the water within the heater and water entering the heater will leak uncontrollably onto the underlying floor. Such flooding could cause extensive damage to the building and its contents. 
   Systems have earlier been described for sensing a leak in a plumbing system, and automatically turning off the water feeding the plumbing system. One type of such detection and control system employs flow monitoring sensors intended to discriminate between normal water flow and abnormal flows attributable to leaks. Such systems monitor either instantaneous flow or flows over a timed period, and send an electrical control signal to a shut-off valve. Such systems are disclosed, for example, in U.S. Pat. Nos. 4,589,435; 4,705,060; 5,000,224; 5,038,802; 5,056,554; 5,086,806 and elsewhere. Water shut-off systems of the aforesaid nature usually involve expensive computerized equipment and generally require specialized programming for proper installation. 
   In still other flood control systems, as disclosed in U.S.  Pat. No. 4,324,268 and 5,240,022, sensors are disposed at floor level for detecting the presence of water, said sensors employing the water to complete an electrical circuit between two closely spaced electrodes. Such systems are unfortunately activated by the small amounts of water employed in the wet-mopping of floors, or small amounts of accidentally spilled water. 
   In yet another type of plumbing flood control system, as disclosed in U.S. Pat. No. 6,523,562, a float-activated electrical switch positioned in a water-accumulating chamber is employed to control an electrically actuated valve. All the aforesaid plumbing flood control systems require a dependable source of electricity, and further permit the possibility of denial of water service to essential but sporadically operating systems such as fire extinguishing systems, lawn watering and cooling systems. 
   U.S. Pat. No. 6,543,471 describes a spring operated mechanism which, in response to the rising of a float device within a collecting pan beneath a water heater, causes a trigger mechanism to close a valve that supplies water to said heater. However, said spring mechanism requires a tether line that extends to an operating lever of the valve, and such arrangement compromises the reliability of the mechanism. Also, the trigger mechanism is subject to malfunction due to effects of corrosion or dirt accumulation. 
   It is accordingly an object of the present invention to provide apparatus of improved reliability for automatically preventing flooding that might be produced by a faulty water heater.  
   It is a further object of this invention to provide apparatus as in the foregoing object which does not require a source of electricity. 
   It is another object of the present invention to provide apparatus of the aforesaid nature which is easily installable and is of durable construction amenable to low cost manufacture. 
   These objects and other objects and advantages of the invention will be apparent from the following description. 
   SUMMARY OF THE INVENTION 
   The above and other beneficial objects and advantages are accomplished in accordance with the present invention by an apparatus for automatically shutting off a water supply to a leaking water heater, said apparatus comprising:
         a) a water-collecting tray having a perimeter sidewall bounded by interior and exterior surfaces, and configured to be positioned beneath said water heater,   b) a float adapted to rest upon water that may accumulate within said tray,   c) guide means that permits vertical movement of said float while preventing substantial lateral movement thereof,   d) a valve housing attachable to the interior surface of said sidewall and comprised of wall structure vertically elongated between upper and lower extremities and having:
           1) a drive rod slideably centered within said valve housing by way of a water tight seal,   2) a first valve member attached to the bottom extremity of  said drive rod,   3) a stationary second valve member incorporated into said wall structure,   4) upper and lower portals located respectively above and below said second valve member, one of said portals permitting entrance of water into said housing, and the other portal permitting egress and routing of said water to said water heater, and   5) a coil spring interactive between said lower extremity and said first valve member, and serving to force said first valve member upwardly, and   
           e) an action arm comprised of a cam portion and an elongated lever portion interactive with said float, said action arm being pivotably joined to said housing adjacent said upper extremity in a manner to permit movement of said action arm in a vertical plane while positioning said cam portion to exert downward force upon the top extremity of said drive rod, whereby,   f) when water accumulates within said tray as a result of leakage from said water heater, said float rises, causing said lever portion to rise, thereby causing said cam portion to release downward force from said drive rod, allowing said spring to drive said first valve member into sealing relationship with said second valve member, thereby discontinuing flow of water to the water heater.        

   
     BRIEF DESCRIPTION OF THE DRAWING 
     For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing forming a part of this specification and in which similar numerals of reference indicate corresponding parts in all the figures of the drawing: 
       FIG. 1  is a top view of an embodiment of the apparatus of the present invention, shown in its stand-by state. 
       FIG. 2  is a front view thereof with portions broken away to show otherwise hidden details. 
       FIG. 3  is a side view thereof with portions broken away. 
       FIG. 4  is a sectional view taken in the direction of the arrows upon the line  4 — 4  of  FIG. 1 . 
       FIG. 5  is a schematic side view showing the position of components during the stand-by state of the apparatus which allows water flow therethrough. 
       FIG. 6  is a schematic side view showing the position of components during the activated state of the apparatus which prevents water flow therethrough. 
       FIG. 7  is a perspective view of a float extension component of the apparatus of this invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to  FIGS. 1–6 , an embodiment of the water heater fail-safe apparatus  10  of this invention is shown comprised of water-collecting tray  11 , float  12 , valve housing  13 , and action  arm  14  interactive between said float and valve housing. 
   Water-collecting tray  11  is comprised of a flat bottom panel  15  and perimeter sidewall  16  bounded by interior and exterior surfaces  17  and  18 , respectively. Said tray is preferably of rectangular configuration, having a size adequate to fit beneath a conventional water heater  19 . The tray may be fabricated of plastic or sheet metal having corrosion resistant characteristics. Sidewall  16  has a uniform height between about 2 and 4 inches. 
   Float  12  is fabricated of plastic as a sealed monolithic structure. It is confined within guide means  20 , attached to said valve housing, that permits vertical movement while preventing lateral movement. In the illustrated embodiment, said guide means is shown comprised of four upright members  21  extending upwardly at four sides of float  12 . 
   Valve housing  13  is provided with seating bracket  22  attachable to the interior surface  17  of said sidewall by means of threaded bolts  23  adapted to penetrate holes in the sidewall and engage nuts  24  which abut against exterior surface  18  of said sidewall. Said valve housing is comprised of wall structure  25  vertically elongated between upper and lower extremities  26  and  27 , respectively. Said wall structure may be fabricated of metal or molded plastic. 
   A drive rod  28 , extending between top and bottom extremities  29  and  30 , respectively, is slideably centered within said valve housing by water tight bushing  31 . A tapered first valve member  32  is attached to bottom extremity  30  of said drive rod. Stationary, second valve member  33  is incorporated into the interior surface  34   of wall structure  25  as an annular shoulder having a taper adapted to achieve flush-fitting engagement with valve member  32 . 
   Upper and lower portals  36  and  371  respectively, are located respectively above and below said second valve sealing member. Said portals, shown in the form of short tubes attached to or integral with wall structure  25  permit attachment of tubes, hoses, or pipes that convey water into or out of valve housing  13 . One of said portals permits entrance of water into the housing, and the other portal permits egress and routing of said water to water heater  19 . 
   A coil spring  39  is interactive between the lower extremity  27  of said valve housing and first valve member  32 , and adapted to force said first valve member upwardly. A bearing ring  40  may be disposed below said first valve member to prevent wear or deformation of said valve member as a result of the force applied by the spring. A seating plug  41  downwardly emergent from first valve member  32  and entering the center of said coil spring assuredly positions the coil spring with respect to interaction with said first valve member. 
   Action arm  14  is comprised of a cam upper portion  42  and an elongated lever portion  43 . Said cam upper portion is comprised of oppositely convex bearing surfaces  46  that meet at tip  48 . Action arm  14  is joined by pivot pin  45  to said valve housing adjacent the upper extremity thereof in a manner to permit movement of said action arm in a vertical plane. The exact position of such pivoted joinder is such as to permit the tip  48  of said cam portion to exert downward force upon the top extremity  29  of drive rod  28  when  lever portion  43  is in a substantially horizontal position. 
   Float extension means, in the form of frame  50  is shown comprised of a base member  51  adapted to rest upon the top of float  12 , and an upwardly directed extension shown as rigid wire  52 . The top of wire  52  is configured to engage lever portion  43  of action arm  14 . One of the functions of the float extension means is to enable the lifting effect of a very small amount of water in the tray to be transmitted to said lever portion. 
   It is to be noted that only slight movement of action arm  14  is required to cause the tip of cam  42  to disengage from drive rod  28 , permitting consequent upward movement of said drive rod. Such construction is in effect a trigger mechanism. It is to be noted that, once the tip of the cam has been dislodged from drive rod  28 , said drive rod is forced upwardly by spring  39 . Such upward motion, acting upon convex bearing surface  46 , rotates arm  14  so that the lever portion becomes located above the cam portion, as shown in  FIG. 6 . 
   Restoration of the device to its stand-by state is accomplished by manually depressing lever portion  43 , which in turn causes bearing surface  46  of the cam to force the drive rod downwardly to its lowermost position where it is secured by abutment with tip  48  of the cam. In such restoration, wire  52  further serves as stop means which limits the movement of said lever portion, and accurately positions tip  48  atop drive rod  28 . 
   In operation, the apparatus of the present invention, when in a stand-by state wherein there is no water in tray  11 , permits water to flow through valve housing  13  en route to water heater  19 .  If water accumulates in said tray as a result of leakage from the water heater, float  12  rises, causing action arm  14  to release drive rod  28 , permitting upward movement thereof drive by spring  39 . This causes the first and second valve sealing members to interengage, thereby blocking flow of water between said portals, with attendant shut off of water supply to water heater  19 . 
   While particular examples of the present invention have been shown and described, it is apparent that changes and modifications may be made therein without departing from the invention in its broadest aspects. The aim of the appended claims, therefore, is to cover all such changes and modifications as fall within the true spirit and scope of the invention.