Patent Publication Number: US-8991415-B1

Title: Fire hydrant break off valve

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to fire hydrants and in particular to preventing a loss of water when a fire hydrant breaks off. 
     Most cities have fire hydrants spaced between 200 and 500 feet apart and next to a street. Such spacing results in a very large number of fire hydrants and proximity to a street results in periodic collisions causing the fire hydrant to break off from its respective water source. The fire hydrants are specifically mounted using break off bolts which includes a narrow belt to result in the fire hydrant breaking off from a break off riser before the break off riser is damaged. 
     Various break off valves have been designed and used to prevent or minimize the loss water when the fire hydrant breaks off from the break off riser, but known break off valves have either failed to operate as intended, or allowed substantial water to escape even when they work as intended. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention addresses the above and other needs by providing a fire hydrant break off valve which includes an offset pivot and a lateral trigger captured between a fire hydrant and fire hydrant break off riser. When a collision breaks the break off bolts holding the fire hydrant to the hydrant break off riser, the lateral trigger is released and the valve rotates to a closed position. The force of water attempting to escape rotates the valve around the offset pivot. The edge of the valve is frustoconically tapered, and after rotating, the valve is pushed against a matching seat to close the valve. The match of the tapered valve against the tapered seat stops or nearly stops all flow of water escaping from the broken hydrant. 
     In accordance with one aspect of the invention, there is provided a fire hydrant break off valve having an offset pivot. The offset pivot results in the valve pivoting nearly instantly to a closed position when the hydrant breaks away from the fire hydrant break off riser. 
     In accordance with another aspect of the invention, there is provided a fire hydrant break off valve having a tapered edge. The taper faces upward and meets a matching riser taper to nearly instantly stop the flow of water. The geometry of the valve&#39;s offset pivot and the tapered edges allows the edge of the valves nearest the pivot to pivot past a respective riser taper and then seal against the riser taper. 
     In accordance with still another aspect of the invention, there is provided a fire hydrant break off valve having a diagonal trigger. The trigger is pivotally attached to the valve at a valve end, and captured between the fire hydrant and fire hydrant break off riser, holding the valve open during normal conditions. When the fire hydrant breaks away, the trigger is released allowing water pressure to close the valve. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
         FIG. 1  is a side view of a fire hydrant and fire hydrant break off riser according to the present invention. 
         FIG. 2  is a cross-sectional view of the fire hydrant and the fire hydrant break off riser according to the present invention taken along line  2 - 2  of  FIG. 1 . 
         FIGS. 3A and 3B  show the fire hydrant and the fire hydrant break off riser according to the present invention with the fire hydrant breaking away from the fire hydrant break off riser. 
         FIG. 4A  shows a side view of a valve of the fire hydrant break off riser according to the present invention. 
         FIG. 4B  shows a front view of the valve of the fire hydrant break off riser according to the present invention. 
         FIG. 4C  shows a top view of the valve of the fire hydrant break off riser according to the present invention. 
         FIG. 4D  shows a bottom view of the valve of the fire hydrant break off riser according to the present invention. 
         FIG. 5A  is a side view of a diagonal trigger of the fire hydrant break off riser according to the present invention. 
         FIG. 5B  is a front view of the diagonal trigger of the fire hydrant break off riser according to the present invention. 
         FIG. 5C  is a rear view of the diagonal trigger of the fire hydrant break off riser according to the present invention. 
         FIG. 5D  is a top view of the diagonal trigger of the fire hydrant break off riser according to the present invention. 
         FIG. 5E  is a bottom view of the diagonal trigger of the fire hydrant break off riser according to the present invention. 
         FIG. 6  is a bottom view of the fire hydrant break off riser according to the present invention. 
         FIG. 7  is a cross-sectional view of the fire hydrant break off riser according to the present invention taken along line  7 - 7  of  FIG. 6 . 
         FIG. 8  is a cross-sectional view of the fire hydrant break off riser according to the present invention taken along line  8 - 8  of  FIG. 6 . 
         FIG. 9  is a valve keeper of the fire hydrant break off riser according to the present invention. 
         FIG. 10  shows a second embodiment of a two section fire hydrant break off riser according to the present invention. 
         FIG. 11  shows the second embodiment after breaking away. 
     
    
    
     Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
     A side view of a fire hydrant  10  and fire hydrant break off riser  12  according to the present invention is shown in  FIG. 1  and a cross-sectional view of the fire hydrant and the fire hydrant break off riser taken along line  2 - 2  of  FIG. 1 . is shown in  FIG. 2 . The fire hydrant  10  is attached to the fire hydrant break off riser  12  by break off bolts  11  through hydrant flanged  15  and top riser flanges  13   a . In the event that a vehicle collides with the fire hydrant  10 , the break off bolts  11  break before the fire hydrant break off riser  12  is damaged. The fire hydrant break off riser  12  is further connected to a water main  14 . 
     The fire hydrant break off riser  12  includes a valve  16  having a pivot axle  20  and held open by a diagonal trigger  18 . A first end of the diagonal trigger  18  is pivotally attached to the valve  16  and a second end of the diagonal pivot  18  is captured between the fire hydrant  10  and fire hydrant break off riser  12  to hold the valve  16  open during normal operation. 
     The fire hydrant  10  and the fire hydrant break off riser  12  with the fire hydrant  10  breaking away from the fire hydrant break off riser  12  is shown in  FIGS. 3A and 3B . As soon as the fire hydrant  10  breaks away from the fire hydrant break off riser  12  the diagonal trigger  18  is released and the valve  16  begins to pivot to a closed position. The water below the fire hydrant break off riser  12  then pushes the valve  16  to complete pivoting and forces an upward facing valve tapered edge  22  against a downward facing tapered seat  21 . 
     A side view of the valve  16  is shown in  FIG. 4A , a front view of the valve  16  is shown in  FIG. 4B , a top view of the valve  16  is shown in  FIG. 4C , and a bottom view of the valve  16  is shown in  FIG. 4D . The valve  16  includes the upward facing circumferential valve tapered edge  22 , diagonal trigger bosses  24  on a top surface  16   a  of the valve  16  for pivotally attaching the diagonal trigger  18  to the valve  16 , and offset axle bosses  26  supporting axles  20  on an axle side  16 ′ of the valve  16  for pivotally attaching the valve  16  to the fire hydrant break off riser  12 . 
     The axle bosses  26  center the pivot axle centerline CL2 a longer length L1 from a far side of the valve  16 , and a shorter distance L2 from a near side of the valve  16 . The valve has a diameter D of L1 plus L2 and the pivot axle centerline CL2 is offset from the valve centerline CL1 an offset O. The valve tapered edge  22  has a taper angle A, and the valve  16  has the thickness T, and the pivot axle  20  is a height H below a top surface of the valve  16 . The diameter D is preferably about 6.326 inches, the offset O is preferably about 1.75 inches, the length L1 is preferably about 4.913 inches, the length L2 is preferably about 1.413 inches, the angle A is preferably about 30 degrees, the thickness T is preferably about 0.5 inches, and the height H is preferably about 1.00 inches. Preferably, the offset O is about 57 percent of a radius R of the valve  16  of the valve  16 . 
     A side view of the diagonal trigger is shown in  FIG. 5A , a front view of the diagonal trigger is shown in  FIG. 5B , a rear view of the diagonal trigger is shown in  FIG. 5C , a top view of the diagonal trigger is shown in  FIG. 5D , and a bottom view of the diagonal trigger is shown in  FIG. 5E . The diagonal trigger  18  preferably includes a hooked second end  18   a  for securely capturing the second end between the fire hydrant  10  and the fire hydrant break off riser  12 . A passage  18   b  is provided in the first end for pivotally attaching the diagonal trigger to the valve  16 . 
     A bottom view of the fire hydrant break off riser  12  is shown in  FIG. 6 . The fire hydrant break off riser  12  includes valve keeper slots  42  which receive valve keepers  40  to retain the valve pivot axle  20  (see  FIG. 2 ). A trigger pocket  32  is provided in a top surface of the riser body  13  for receiving the hooked second end  18   a  of the diagonal trigger  18  during normal operation. 
     A cross-sectional view of the fire hydrant break off riser  12  taken along line  7 - 7  of  FIG. 6  is shown in  FIG. 7  and a cross-sectional view of the fire hydrant break off riser  12  taken along line  8 - 8  of  FIG. 6  is shown in  FIG. 8 , and the valve keeper  40  is shown in  FIG. 9 . The fire hydrant break off riser  12  includes a riser body  13  having a top flange  13   a  for attachment to the fire hydrant  10 , and a bottom flange for attachment to the water main  14 . The valve keeper slot  42  allows the valve keeper  40 , valve  12  and valve pivot axle  20  to be installed and removed from the fire hydrant break off riser  12 , and holds the valve  16  in place in the fire hydrant break off riser  12 . A screw  44  holds the valve keeper  40  in the valve keeper slot  42 . 
     A second embodiment of a two section fire hydrant break off riser  12   a  and  12   b  is shown in  FIG. 10  and the fire hydrant break off riser  12   a  and  12   b  after breaking away is shown in  FIG. 11 . The bottom riser  12   a  is very similar to the riser  12 , but without the trigger pocket  32 . The top section  12   b  includes a second pocket  32   a  and an end of the second diagonal trigger  18   a  resided in the pocket  52  during normal operation. The riser  12   b  also includes a circumferential notch  50  creating a weak ring around the riser  12   b . The break off bolts  11  of the first embodiment are replaced with full strength bolts  11   a , and upon a sufficient impact, the riser  12   b  separates at the notch  50 , the diagonal trigger  18   a  is released from the pocket  52 , and the valve  16  is free to pivot to a closed position. 
     While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.