Abstract:
The backflow valve of the present invention includes a valve housing having a cavity therein with an inlet and an outlet to the valve cavity. A switch is in communication with the valve cavity and is moveable from an off position to an on position in response to liquid filling the valve cavity. A valve is moveable in response to the movement of the switch to the on position. The valve moves to a closed position shutting off the fluid flow through the backflow valve.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a backflow valve and specifically to a backflow valve that can be used in a home sewer conduit for preventing backflow conditions. 
   Most homes and businesses include a sewer outlet that leads to a city sewer system. On occasion the sewer outlet will back up, and the sewage will back up into the basement or home of the individual owner. It is desirable to provide a backflow valve that prevents the backflow of sewage into the home. 
   Therefore a primary object of the present invention is the provision of a backflow valve that will prevent backflow of sewage into a home or office. 
   A further object of the present invention is the provision of a backflow valve that includes both first, second and third valve members capable of closing off both the entrance and the exit of sewage and bladder seal between entrance and exit flap valves assuring a drop tight seal when a backflow condition occurs. 
   A further object of the present invention is the provision of a backflow valve that is simple in operation and utilizes a minimum of moving parts. 
   A further object of the present invention is the provision of a backflow valve that can be easily installed into a conventional sewage system of a home, office or other facility. 
   A further object of the present invention is the provision of a backflow valve that is economical to use, durable in use, and efficient in operation. 
   SUMMARY OF THE INVENTION 
   The foregoing objects may be achieved by a backflow valve for detecting a backflow condition of liquid flowing through a conduit. The backflow valve comprises a valve housing including a valve cavity, an inlet to the valve cavity for receiving the liquid flowing through the conduit and an outlet to the valve cavity for permitting the liquid to exit from the cavity and return to the conduit. A switch is in liquid communication with the valve cavity. The switch is moveable from an off position to an on position in response to liquid filling the valve cavity from a normal liquid level to a backflow liquid level above the normal liquid level. A valve is moveable from an open position permitting liquid flow from the inlet through the valve cavity to the outlet to a close position shutting off liquid flow from the inlet into the valve cavity. A valve actuator is moveable from a first position permitting the valve to be in the open position to a second position moving the valve from the open position to the closed position. The valve actuator is responsive to the switch being in the on position to move the valve from the open to the closed position. 
   According to another feature of the present invention the valve actuator is a bladder that is inflatable to move from the first to the second position. 
   According to another feature of the present invention the valve comprises a moveable flap that is moveable in response to inflation of the bladder to move from the open to the closed position. 
   According to another feature of the present invention the valve comprises both a first flap and a second flap. The first flap is moveable from the open to the closed position to shut off liquid flow from the inlet to the valve cavity. The second flap is moveable from the open to the closed position to shut off liquid flow from the valve cavity to the outlet. 
   According to another feature of the present invention the first and second flaps are part of a flexible member that is biased towards the open position, but is moveable in response to being engaged by the bladder to the closed position. 
   According to another feature of the present invention the flexible member is elastic and returns automatically to the open position when the bladder is in the first position. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded perspective view of a backflow valve of the present invention. 
       FIG. 2  is a perspective view of the backflow valve with the internal components removed for illustrative purposes. 
       FIG. 3  is a sectional view taken along line  3 - 3  of  FIG. 2  but showing the internal components in place. 
       FIG. 4  is a sectional view similar to  FIG. 3 , but showing the bladder in the inflated condition. 
       FIG. 5  is a sectional view taken along line  5 - 5  of  FIG. 2  but showing the internal components in place. 
       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 a sectional view taken along line  8 - 8  of  FIG. 3 . 
       FIG. 9  is a schematic view of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Below is a description of the preferred embodiment of the present invention. This description is of the preferred embodiment, and other embodiments may incorporate the same invention while at the same time producing the same result as the preferred embodiment. 
   Referring to  FIG. 1 , a backflow valve  10  is shown in an exploded view. Backflow valve  10  includes a valve box  12  which discloses a valve cavity  14 . Valve cavity  14  is comprised of a bladder cavity  15  and an L-shaped float cavity  18  which includes a first L portion  21  and a second L portion  23 . All the cavities  15 ,  18 ,  21  and  23  are in fluid communication with one another. A separate air inlet cavity  16  is separate from and is not in communication with the valve cavity  14 , the bladder cavity  15 , the L-shaped float cavity  18 , the first L portion  21  and the second L portion  23 . Extending through the end wall of box  12  is an air tube inlet  17 , and extending between the air inlet cavity  16  and the bladder cavity  15  is an air tube notch  19 . As can be seen in  FIG. 5 , an air tube or conduit  58  extends from the exterior of the box  12  through the air tube inlet  17  and the air tube notch  19 . Also, an electrical wire  60  extends through air tube inlet  17  and also through a sealed opening  61  into the second L portion  23  of L-shaped float cavity  18 . 
   Within the second L portion  23  is a float switch  20  which is comprised of an anchor  74  and a float  76  that pivots about pivot  78  of anchor  74  ( FIG. 5 ). The float switch  20  is electrically connected to the wire  60 . While a float switch may be used, other apparatus for detecting the level of fluid within L portion  23  of L-shaped cavity  18  may be used. 
   Within bladder cavity  15  is a valve member  22  which includes a first valve flap  24  and a second valve flap  26 . The valve member  22  may be comprised of a flexible material such as rubber or the like. The flaps  24 ,  26  are capable of bending downwardly, but have sufficient resiliency to return to their original position shown in  FIG. 1 . 
   Above the valve flap  22  is a bladder collar  28  having an oval shaped opening  30  therein. 
   Above the bladder collar  28  is a convoluted bladder member  32  which includes a bladder  34  which is oval in shape to conform to opening  30  and which includes accordion folds  36  therein. 
   The bladder member  32  is comprised of a flexible material such as rubber or the like and includes sufficient resiliency to permit the bladder  34  to move in response to air pressure from the position shown in  FIG. 3  to the expanded position shown in  FIG. 4 . The bladder member  32  however has sufficient resiliency to return to its original position shown in  FIGS. 1 and 3  when air pressure is removed from the upper portion of the bladder  32 . 
   Above the bladder member  32  is a manifold  38  which is comprised of an upper manifold sheet  40  and a lower manifold sheet  42 . The air tube  58  extends through air tube notch  19  as shown in  FIG. 5  and is in communication between the upper and lower manifold sheets  40 ,  42  as illustrated schematically by the numeral  58  in  FIGS. 3 and 4 . The manifold  38 , the bladder  32 , the bladder collar  28 , and the valve member  22  each include a plurality of screw holes  46  around their perimeters for receiving screws that extend into the valve box  12 . 
   A transparent lid  48  having a plurality of screw holes  50  therein is fitted and screwed within a recess  52  in the upper edges of the box  12  so as to create a fluid tight seal over box  12 . 
   A liquid or sewage entrance  56  is in a pipe shape and extends into communication with the valve cavity  14 . Similarly a liquid or sewage exit  54  leads from the valve cavity  14  to return the sewage or liquid to the conduit through which it flows. In operation, the liquid entrance  56  is placed in communication with the upstream end of the sewage conduit and the liquid exit  54  is placed in communication with the downstream portion of the sewage conduit. 
   Referring to  FIG. 5 , the second L portion  23  includes a sloped floor  62  which slopes to a lower end in communication with the L-shaped portion  21 . As can be seen in  FIG. 3 , the L-shaped portion  21  is in fluid communication with the liquid entrance  56 . Similarly, the bladder cavity  15  is in communication with the liquid exit  54 . 
   Referring to  FIGS. 6 and 7 , an inlet opening  66  provides communication from the inlet opening  66 , and an outlet opening  64  is in communication with the liquid exit  54 . 
     FIGS. 3 ,  4  and  5  show the operation of the backflow valve  10 . In normal operation, the sewage or liquid enters entrance  56 , then into L-shaped cavity  21 , then passes through inlet opening  66  into bladder cavity  15 , then passes through outlet opening  64  and then into liquid exit  54 . As long as there is no blockage, the valve  10  continues to function in this manner which is shown in  FIG. 3 . Arrow  84  shows the direction of fluid flow. 
   However, if a backflow condition occurs or a blockage occurs,  FIG. 5  shows the switch  20  which includes the float  76  that moves to the position shown in shadow lines in  FIG. 5 . This movement is caused by the rise of fluid within L-shaped chamber  18  which includes cavities  21  and  23 . This causes the switch  20  to move from its closed position to its open position thereby actuating fluid or air pump  82  shown in  FIG. 9 . A power source  80  is also shown in  FIG. 9 . The air pump  82  pumps fluid or air through air tube  58  into the manifold  38 . From the manifold  38  the air pressure moves through an air opening  72  against the bladder  32 . The bladder  32 , because of its accordion folds  36  moves from the position shown in  FIG. 3  to the position shown in  FIG. 4 . In this inflated condition, the bladder  32  engages the first and second valve flaps  24 ,  26  and urges them to the position shown in  FIG. 4  which is in covering sealing relationship over the inlet opening  66  and the outlet opening  64  respectively. In this position, the valve flaps  24 ,  26  prevent fluid from passing from the entrance  56  outwardly through the exit  54 . Thus the backflow valve  10  will remain in a closed condition so long as blockage occurs and a backflow condition is present. However, if for some reason the fluid level lowers in first L portion  21  and second L portion  23 , the switch  20  will again move to its closed position and the air will be permitted to exit from bladder  32 . This causes the bladder  32  to return to its position shown in  FIG. 3 . Facilitating of the deflation of bladder  32  may be accomplished by actuating a release valve (not shown) in the air pump  82  or in the conduit  58  to permit the air to escape. 
   In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in the form and the proportion of parts as well as in the substitution of equivalents are contemplated as circumstance may suggest or render expedient without departing from the spirit or scope of the invention as further defined in the following claims.