Patent Publication Number: US-8534324-B2

Title: Sump pump with reduced-noise check valve

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/731,306, filed Oct. 28, 2005, which is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention is related to check valve assemblies for use with sump pumps. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment of the present invention, a system is provided for reducing noise produced by a falling liquid column in a discharge line connected to a sump pump through a check valve, when the check valve is moved from an open position to a closed position. The system includes a closed-end tube in fluid communication with the check valve and the discharge line to receive a portion of the residual head of liquid in the discharge line upon closing of the check valve when the pump is turned off. 
     In one implementation, the check valve includes a resilient flapper valve element in a valve body attached to the discharge port of the sump pump. The flapper valve element moves between open and closed positions. The portion of the valve body on the side of the flapper valve element facing away from the pump forms a side-wall port, and is also connected to a discharge line. A closed-end tube encloses the side-wall port and extends away from the valve body in the direction of the discharge line, to receive a portion of the residual head of liquid in the discharge line upon closing of the flapper valve when the pump is turned off. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a side elevation of a check valve assembly embodying the invention; 
         FIG. 2  is an end elevation taken from the left-hand end of  FIG. 1 ; 
         FIG. 3  is a top plan view of the assembly of  FIGS. 1 and 2 ; 
         FIG. 4  is a section taken along line  2 - 2  in  FIG. 1 ; 
         FIG. 5  is a side elevation of the left-hand body section in the assembly of  FIGS. 1-4 ; 
         FIG. 6  is an end elevation taken from the left-hand end of  FIG. 5 ; 
         FIG. 7  is an end elevation taken from the right-hand end of  FIG. 5 ; 
         FIG. 8  is an exploded side elevation of the right-hand body section, the flapper valve element and the attachment screws in the assembly of  FIGS. 1-4 ; 
         FIG. 9  is an end elevation taken from the left-hand end of  FIG. 8 ; 
         FIG. 10  is a side elevation of the closed-end tube section attached to the left-hand body section in the assembly of  FIGS. 1-4 ; and 
         FIG. 11  is an end elevation taken from the right-hand end of  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENT 
     Although the invention will be described in connection with certain preferred embodiments, it will be understood that the invention is not limited to those particular embodiments. On the contrary, the invention is intended to include all alternatives, modifications and equivalent arrangements as may be included within the spirit and scope of the invention as defined by the appended claims. 
     Turning now to the drawings, a check valve assembly  10  is adapted to be attached to the discharge port of a sump pump (not shown). The movable valve element is a conventional flapper valve element  11  contained between a pair of body members  12  and  13  connected between the pump discharge nozzle and a pipe or hose extending upwardly away from the sump pump for carrying liquid discharge from the sump to a suitable drain. The two body members  12  and  13  and the flapper valve element  11  all have mating outer flanges, each of which forms four registered holes for receiving four screws  12   a - d  that thread into tapped holes in the outer body member  13  to draw the body members  12  and  13  tightly against opposite sides of the flapper valve element. 
     A circular, cupped central portion  14  of the flapper valve element  11 , which is made of a resilient material such as rubber, is hinged to the outer portion of the valve element on only one side so that the remainder of the central portion  14  can pivot between open and closed positions. The portion of the inner body member  12  adjacent the movable central portion  14  of the flapper valve element forms an annular seating surface  15  for the mating outer annular portion of the central portion  14 . As can be seen in  FIG. 8 , the seating surface  15  lies in a plane that intersects the center line of the valve assembly at an acute angle, which has the effect of reducing the distance through which the valve element must move between its open and closed positions. 
     When the sump pump is operating, the hydraulic pressure produced by the pump forces the flapper valve element  11  to its open position, allowing liquid to be discharged from the pump into the outer body member  13  and then on into the discharge line attached to that outer body member. When the pump is turned off, the resilience of the flapper valve element  11  causes it to return toward its closed position, and the hydraulic head produced by the column of liquid in the discharge line forces the flapper valve element  11  tightly against the seating surface  15  so that liquid from the discharge line cannot flow back into the pump. 
     As can be seen in  FIG. 5 , the outer body member  13  is stepped so that it can receive discharge lines of different diameters. For example, the outermost segment  16  of the outer body member  13  may have a diameter selected to receive a standard 1.25-inch PVC pipe, while the next segment  17  has a diameter selected to receive a standard 1.5-inch PVC pipe. 
     Extending laterally away from the inner end portion of the outer body member  13  is an elbow section  20  that joins the body member  13  to a closed-end tube  21  extending generally parallel to the discharge line attached to the body member  13 . In the example illustrated, the central axis of that portion of the elbow section  20  joined to the body member  13  intersects the central axis of the body member at an angle of about 35 degrees, although it will be understood that other angles may be used. The central axis of the outer portion of the elbow section  20  is generally parallel to the central axis of the body member  13 . The outer end of the elbow section  20  is stepped outwardly at  20   a  to fit over the outer surface of the open end of the tube  21  that is closed at its opposite end  22 . The elbow section  20  and the closed-end tube  21  may be joined with conventional PVC adhesive, or they may be threaded to allow them to be threaded together. The elbow section  20  is preferably formed as an integral part of the outer body member  13 , such as by molding them as a single unitary part. 
     The purpose of the elbow section  20  and the closed-end tube  21  is to reduce the noise produced when the flapper valve closes. When the sump pump is turned off, the substantial column of liquid that exists in the discharge line typically falls and slams the flapper valve closed, sometimes vibrating the valve element in the process, producing substantial noise. However, with the auxiliary chamber formed by the elbow  20  and the tube  21 , a portion of the liquid column in the discharge line flows into the elbow section  20 , forcing liquid from the elbow section  20  up into the tube  21 , which has the effect of substantially reducing the amount of noise produced by the closing of the flapper valve element. The closed-end tube  21  preferably contains a volume of air, so that the liquid that enters the elbow section  20  and the tube  21  compresses the air within the tube, thus dissipating a portion of the energy of the falling liquid column. 
     While particular embodiments and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations may be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims.