Abstract:
A pipe coupling for use with a fire hydrant or like has automatic shut-off features in the event of breakage of the fire hydrant. The breakaway pipe coupling includes an extension join to a valve body with a flow passage way extending through the extension and valve body. A shut-off valve is moveably mounted to the extension and is bois for movement toward a valve seat located in the valve body. A wedge extends between the extension and the shut-off valve, wedging the shut-off valve in a open position away from the valve seat. Extension and valve are separably joined together in that the extension includes a frangible portion which severs upon application of an impact force to pipe coupling. This allows the wedge to become dislodged, with the shut-off valve being urged in a position towards the valve seat.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention pertains to pipe couplings for water supply lines and in particular to pipe couplings which provide an automatic shut-off if the line should suddenly become open.  
         [0003]     2. Description of the Related Art  
         [0004]     In a number of different applications, it is important that the flaw of water be quickly and automatically stopped should a break in the water supply line occur. For example, should fire hydrants be subject to a lateral impact or blow from a vehicle, damage to all or some portion of the water supply line, including the fire hydrant itself, is likely. The various portions of a fire hydrant water supply line have widely varying material and replacement costs. It is desirable to provide a sacrificial portion or special purpose reusable portion which limits resulting damage in a manner which is most economical for subsequent repair of the water line.  
         [0005]     Typically, fire hydrants and other water supply devices are located remotely from the main water supply. For example, municipal water supply lines are often buried deep within the ground and a riser portion of considerable height is required to reach the ground surface were the fire hydrant is located. Various arraignments have been proposed for riser constructions, including arrangements described in the U.S. Pat. Nos. 4,127,142; 4,717,178; 5,609,179 and 6,401,745. In each of these arrangements some provision is made for automatic shut-off of2 water flow through the riser portion of the water line. For example, in the U.S. Pat. No. 4,127,142 a valve member is blocked open by a bar welded to a sandwich flange. Weakened bolts holding the sandwich flange are severed upon impact, allowing the valve to close and thereby shut-off flow through the water line. The arrangement provides a slow closing feature to reduce water hammer. U.S. Pat. No. 4,717,178 employs a frangible ring to separate upper and lower barrel sections of a fire hydrant. U.S. Pat. No. 6,401,745 employs a pair of flaps which close to seal a cylindrical sleeve to prevent water flow to a fire hydrant. U.S. Pat. No. 5,609,179 employs a rod having a frangible end which, upon breaking, allows a valve disk to rotate to a closed position.  
       SUMMARY OF THE INVENTION  
       [0006]     Advances in the field of breakaway pipe couplings are constantly being sought. It is important that the more expensive components of a water line system be protected from damage when subjected to an impact force such as that of a motor vehicle. Also, it is important that water flow be quickly and reliably stopped upon breakage of some portion of the water line system. Accordingly, it is in object of the present invention to provide a breakaway pipe coupling having an improved automatic shut-off.  
         [0007]     Related objects of the present invention include the provision of a breakaway pipe coupling with a sacrificial portion which reliably limits damage to a localized area, preventing damage to critical components of a water line system, such as a valve assembly.  
         [0008]     A further object of the present invention is to provide a breakaway pipe coupling of the above-described type which reliably impedes water flow, upon damage to the system, which effectively stops or terminates flow at the point of breakage.  
         [0009]     A further object of the present invention is to provide reliable stopping of water flow at a point of breakage in a fire hydrant supply system which provides a high capacity water flow at elevated pressures of 150 lbs. per square inch, or more. With such systems, even relatively small leakage can adversely impact an accident site with a substantial accumulation amount of water.  
         [0010]     It has been found important that the valve member immediately achieve full closure upon activation, despite fouling of the valve surfaces. Due to the forces involved, a slight misalignment of the valve and valve seat might still result in a substantial closing of water flow at the breakage sight. However, due to the elevated flow rates and pressures involved, a substantial but incomplete valve closure might still allow a substantial amount of water to quickly accumulate an accident site. Its been found that, should valve misalignments occur during the first moments of a closing operation, the valve will not have an opportunity to adjust its position due to the substantial hydraulic forces involved.  
         [0011]     These another objects according principles of the present invention are attained in [claim  1 ]. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a perspective view of a pipe coupling constructed according principles of the present invention;  
         [0013]      FIG. 2  is a top plan view thereof;  
         [0014]      FIG. 3  is side elevational view thereof;  
         [0015]      FIG. 4  is cross-sectional view taking along the line  4 - 4  of  FIG. 2 ;  
         [0016]      FIG. 5  is a cross-sectional view similar to that of  FIG. 4 , but showing valve in closed position; and  
         [0017]      FIG. 6  is side elevational view showing the pipe coupling in combination with a fire hydrant. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]     Referring know to the drawings and initially to  FIG. 1 , a pipe coupling according to principles of the present invention is generally indicated at  10 . Pipe coupling  10  defines an eternal passage way for fluid flow in the direction of arrow  12 . Arrow-shaped in  FIG. 14  is provided on the body of the pipe coupling to provide a convenient indication to the installer or other workmen. Pipe coupling  10  has potential commercial application for use in large volume, high pressure fluid systems such as municipal water way systems. Pipe coupling  10  provides an improved automatic shut-off of fluid flow in the event of breakage of system components located downstream of the pipe coupling. With reference to  FIG. 6 , pipe coupling  10  is shown in combination with a municipal or commercial water way system in which a conventual fire hydrant  20  terminates flow from a main supply. An angle fitting  22  and riser pipe  24  provide connection to the main fluid supply couple to end  26  of coupling  22 . In the example illustrated in  FIG. 6 , pipe coupling  10  provides automatic shut-off should the downstream component (herein hydrant  20 ) become damaged resulting in a rupturing of the fluid system. Such damaged to fire hydrant devices typically arises from accidental contact with a motor vehicle such as a passenger car or a piece of earth moving equipment. Damage could also arise from natural disasters such as an earth quake or debris-laden foot waters. Has indicated in the example system, pipe coupling  10  is employed to provide automatic shut-off of water flow under relatively high pressure conditions, such as those encounter immiscible and commercial water supply systems. You will be greatly appreciated by those skills of the art, that pipe coupling  10  could also can be employed with other pipping systems and fluids, such as crud oil, refined petroleum, or commercial fluids such as by products and commercial chemicals. Pipe coupling  10  provides automatic shut-off protection for downstream components such as the fire hydrant illustrated in the example, as well as pipe ridge crossings, expansion loops, or control valves which are susceptible to damage, resulting a rupture of the sued system. The pipe coupling  10  illustrated in the figures is disposed in a generally vertical orientation, but could be arranged in a horizontal or other non-vertical position as desired.  
         [0019]     Referring know to  FIGS. 1-4 , pipe coupling  10  may be comprised of a continues unitary body from its inlet end  30  to its outlet and  32 . However, as illustrated, it is generally preferred that the pipe coupling be provided in two parts including an up stream valve part generally indicated at  36  and a downstream extension part generally indicated at  38 . Preferably, the valve part and extension part are provided with connecting flanges  40 ,  42  and  44 ,  46 , respectively. The lower flange  44  of extension part  38  is secured to the upper flange  42  of valve part  36  by a series of shredded bolt fasteners  48 , as is shown in the art. The upper flange  46  is connected to the downstream device to be protected, such as the fire hydrant  20  shown in  FIG. 6 . Unprotecting and above ground device such fire hydrant  20 , it is assumed that the fire hydrant will most likely become damaged by inadvertent contact with a moving vehicle providing a sideways impact force which is off excess, usually perpendicular to the direction of arrow  12  (see  FIG. 1 ). In this event, four reasons to be discussed herein, it is generally preferred that the upper flange  46  of extension part  38  be directly connected to the fire hydrant or other protected devise to provide the most direct transmission of impact force from the fire hydrant to the extension part  38 . As indicated in  FIG. 6 , the lower flange of valve part  36  is connected to the fluid supply herein biser pipe  24 .  
         [0020]     Referring know to  FIG. 4 , it can be seen that extension part  38  and valve part  36  defined quacksual water passage ways, with the bolted connection of flanges  42 ,  44  providing a fluid-type connection. With additional reference to  FIG. 1 , it can be seen at valve part  36  includes a sideways protrusion  52  defining a cavity  54  visible in  FIG. 4 . Cavity  54  receives a shut-off valve  60  having a generally flat plate-like structure with a end wall  62  and a skirt or a side wall  64  needing at outside corner  66  of predetermine curvature. Together, end wall  62  and side wall  64  cooperate to form a recess or cavity  68  at the under side of shut-off  60 .  
         [0021]     Referring again to  FIG. 4 , a generally cylindrical mounting lug  72  cooperates with end walls  62  to provide a hollow recess  74  opening in generally in the same direction as recess  68 . The outside surface of log  72  provides a convenient attachment point for the upper end of coil spring  78  is generally preferred that coil spring  78  be maintained captive on the under side of shut-off valve  60 . As indicated in  FIG. 4 , with shut-valve  60  in the fully open position, coral spring  78  is compressed by the outer wall of housing protrusion  52 . An optional witness hole or weep hole  82  is formed in end wall  62  adjacent a cup-like packet member  84 .  
         [0022]     The biases force off spring  78  its restrained by a wedge member  88  having a lower end contacting pocket  84  in a upper end received in a passage way  92  formed in an internal protrusion  94  extending from extension part  38 , in an inward direction, adjacent flange  46 . In the preferred embodiment, passage way  92  and the upper end of wedge  88  are shredded for complementary shredded for joinder. Alternatively, the upper end of wedge  88  may be secured to extension part  38  using virtually any available means sufficient to maintain engagement between wedge  88  and extension part  38 , despite impact forces applied to the extension part.  
         [0023]     Referring again to  FIG. 4 , in a preferred embodiment, extension part  38  includes a frangible feature to insure that extension part  38  is ruptured upon application of an impact force to a protected device mounted downstream of the extension part. In the example system shown in  FIG. 6 , as mentioned, the impact force is anticipated to be applied to hydrant  20  which is securely bolted or other wise fasten to the downstream on  32  of extension part  38 , for efficient transmission of the impact force to the extension part. As can be seen in  FIG. 4 , for example, extension part  38  is providing with two annular recesses  96 , located adjacent flange  46  and annular recesses  98  located adjacent flange  44 . The annular recesses provided lines of weakness in the body of extension part  38 , causing the extension part to fail or rupture at the annular recesses. Preferably, the depth of the annular recesses is matched to the side walls and structure of the extension part to insure that application of a impact force to the fluid system will reliably result in breakage in the extension part, rather then the protected devise, herein hydrant  20  for the valve part  36 . In a preferred embodiment, extension part  38  is intended to be the weakened sacrificial member which must be replaced after an automatic valve closing. As mentioned, the upper end of wedge  88  remains secure to protrusion  94  adjacent flange  46 , thus insuring that the wedge  88  remains secure to a massive structure, such as the protected fire hydrant  20  after a successful automatic shut-off event.  
         [0024]     In operation, pipe coupling  10  provides automatic closure of flow through its internal passage way. In the example illustrated in  FIG. 6 , it is assumed that an impact force is laterally applied to the protected device or hydrant  20 . This sideways force is transmitted to extension part  38  and causes the extension part to ruptured at ether analis  96 ,  98  or both. This allows the hydrant  20  to follow the lateral motion generated by the impact force, with wedge number  88  following the hydrant and remaining fixable coupled there to. As a result, the bottom end of the wedging number  88  used contacted with pocket  84 , allowing shut-off valve  60  to rotate toward a closed position, away from housing protrusion  52 , under force of spring  78 . In a preferred embodiment, spring  78  provides only and initial motion to the shut-off valve, causing the shut-off valve to enter the fluid flow through the pipe coupling. On entry into the fluid flow, the free end of the shut-off valve contacts the upwardly directed fluid flow and is moved along with the direction of the fluid flow toward the closed position illustrated in  FIG. 5 . As mentioned, the underside of shut-off valve  60  is formed with a hollow recess which aids in capturing the fluid flow and enhance the displacing force made available by the fluid flow to quickly bring the shut-off valve  62  the close position illustrated in  FIG. 5 . During the closing operation, the shut-off valve  60  pivots in a clock wise direction about mounting pin  102 .  
         [0025]     Referring again to  FIG. 4 , the housing portion of valve part  36  defines a valve seat  106  immediately downstream of  10   102 . Preferably, valve seat  106  has a frusto chronicle configuration looking at other conventual shapes, if desired. As mentioned, deskirt or side wall  64  of the check valve has an outside corner which is surrounded or curved. Preferably, the outside corner is continuously curved to present a convex seeding surface which engages the valve seat  106  with a line (ie circle) contact. It has been found that special attention must be paid to the seating operation of the check valve in an automatic shut-off event. Assuming a breakage or ruptured downstream of a check valve, a substantial flow is directed through the inter boar of valve part  36 . Concurrently, it is assumed that wedge  88  is free to move in a downstream direction, clearing the wedging contact with pocket pd 4  located on the topside of shut-off valve  60 . This removes the restraint against expansion of spring  78 , which urges the shut-off valve toward valve seat  106 . The reference  108  is applied to the tip of shut-off valve  60 , located at the bottom corner of side wall  64 , opposite end  102 . Initially, as can be seen  FIG. 4 , the top wall  62  of the shut-off valve is inclined away from the direction of fluid flow. Static fluid pressure urges the shut-off valve in the close position illustrated in  FIG. 4 . With wedge  88  being moved, spring  78  urges the shut-off valve  60  in a clock wise direction, initially bringing top wall  62  into alinement with the direction of fluid flow, preferably in axial direction with respect to valve part  36 ). At this point, the shut-off valve is in a neutral or unstable position and it is important that spring  78  continues control of the shut-off valve so as exposed the underside of the shut-off valve to fluid flow through the valve part. Upon the initial exposure of the underside of the shut-off valve  60  to the fluid flow, fluid pressure directs the shut-off valve toward a close position eliminating further need for spring  78  to urge the shut-off valve to its completed, closed position. As can be seen in  FIG. 4 , a cavity  112  is formed adjacent tip  108 . Full pressure trapped in cavity  112  accelerates the closing of the shut-off valve. There after, pressure becomes trapped within a hollow mounted stub  74 , further accelerating the shut-off valve closure. Eventually, the entire cavity formed at the bottom of shut-off valve  60  is acted upon by the pressure of fluid flowing through valve part  36 , causing the shut-off valve to seat with a substantial force. There after, static pressure maintains the shut-off valve in contact with the valves seat. Due to the magnitude of the forces involved, the initially orientation of the shut-off valve upon contact with the valve seat is maintained as long as fluid pressure applied to the valve part. It has been observed that the shut-off valve is unable to vibrate, fluctuate or otherwise move to a re-seated position, preserving the initial orientation of the shut-off valve when it first contacts the valve seat. It is important therefor that optima seating of the shut-off valve is obtained at the first instant of closing with valve seat  106 . The rounded corner of the shut-off valve and the frusto chronicle valve seating configuration is found unofficial and providing the desirable initial eliminate of the shut-off valve with the valve seat. Further, will be recognized that the concave recess formed at the bottom side of the shut-off valve is important in maintaining a stable path of movement as the shut-off valve is urged toward valve seat  106 . As will be appreciated by those skill in the art, the archit. hendge arms  116  which are pined at  102  to the valve part housing are allowed at least a minium freedom of movement to allow the shut-off valve seating surface to seeks its initial line contact with valve seat  106 . As a practical consideration, some amount of play of the pine connection  102  is expedient in light of manufacturing intolerances of the components, which are preferably of cast iron construction and large forces associated with the whole conditions involved. As mention, the interboard of valve part  36  of the illustrated embodiment has a 6 inch diameter and contains fluids at flow pressures ranging between 150 and 200 pounds per square inch. Further, the source of fluid pressure is assumed to have a large capacity such that the fluids and flow pressures do not decrease over time, particularly within the time frame of an automatic closing operation. Cordially, it is important that the shut-off valve be confid in a control manner as it moves toward valve seat  106  to assure that initial closing of the shut-off valve results in substantially complete shut-off of fluid flow through valve part  36 .  
         [0026]     As mentioned, shut-off valve  60  may be provided with a witness hole  82  located at the center of its top wall  62 . In the prefer embodiment, with valve pipe  36  having a 6 inch boar, witness hole pd 2  has a diameter on the order of ⅛ inch. Due to the relatively small size of the witness hole, and the elevated pressure of the fluid contained within valve part  36 , a limited high pressure spray of fluid imitates downstream of the valve part, thus providing a ready visual indication of location of damaged, to repair personnel. A witness hole is also believed to provide some relief of water hammer conditions which may be present in the system at the time of automatic shut-off closure.