Self-cleaning non-return drainage valve
BACKGROUND OF THE INVENTION 
     This invention relates to a non-return drainage valve provided with a self-cleaning plug and port assembly adapted for use in the floor portion of a burial casket or other container which is located in an environment wherein fluids external to the container intermittently rise from below the container to above the floor of the container. The valve allows the drainage of fluid from the container and prevents the backflow of liquid through the valve into the container due to a liquid level rising above the drainage valve located in the floor of the container. 
     In various containers, particularly in burial caskets, it is desirable to utilize drainage valves to allow the drainage of fluid, gases or liquids, from the container, and to prevent the flow of liquids thereinto due to liquids rising above the floor of the container in which the drainage valve is located. 
     One example of such a valve is disclosed in Blanchard U.S. Pat. No. 3,542,059. 
     In many such containers, debris from the container or from fluid contained within the container tends to pass with the flow of fluids through the drainage valve. In many instances the debris is of such size and composition so as to be unable to pass through the drain port in the drainage valve. In these cases, the debris tends to block the drain port and restrict or completely block the flow of fluids from the container through the valve. Likewise, non-liquid material may be disposed on the exterior of the container. This material may block the discharge passage of the drainage valve and prevent the drainage of fluid, gases or liquids, from the container. 
     This is particularly true in burial caskets and the like in which a casket has a decomposing corpse therein which produces fluids, liquids, and gases which should be drained from the burial casket. Since the burial caskets are normally placed underground, there is a problem of water entering the burial caskets through the drainage valve when the water table in the ground rises above the drainage valve in the floor of the burial casket. Further, debris from the ground can be carried with the rising water into or against the valve discharge passage thereby blocking the passage. 
     When the level of the water table in the ground is below the drainage valve in the burial casket, then the drainage valve opens to permit the drainage of the fluids from the interior of the burial casket. However, when this occurs, it is sometimes possible for debris from the interior of the burial vault and parts of the decomposing corpse to block the drain port in the drainage valve. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention there is provided an improved drainage valve which overcomes the above problems, which operates to permit desired drainage of fluids and to prevent the backflow of liquids therethrough, and which precludes the blockage of the drainage valve by debris. 
     A valve incorporating the present invention includes probe means movable with a buoyant plug member to extend through and effect clearing of the valve drain port and discharge passageway when the plug member moves towards and away from the drain port. 
     The desired buoyancy of the plug member can be effected in numerous ways, e.g., by using a solid plug member constructed of materials less dense than the density of the backflowing liquid or by constructing a plug member of denser material but containing an air space to provide a buoyant force. 
     More specifically, the plug member is located beneath a drain port having a seating surface and is maintained generally below the drain port by retaining means. The drain port is typically located in the floor of the container or burial casket to be drained. 
     Access is provided to the drainage valve discharge passageway to permit fluids draining from the container or burial casket to drain through the drain port and out through the valve discharge passageway and also to permit backflowing liquids from the exterior of the container or burial casket to enter the drainage valve and contact the plug member. As the backflowing liquid level rises, the plug member is buoyed upward toward and against the drain port seating surface thereby closing the valve and preventing the backflowing liquid from flowing through the drain port into the interior of the burial casket or container. 
     In this closed valve position, an upper part of the probe means, having moved with the plug member, extends through the drain port to push away debris and preclude blockage. 
     When the level of the backflowing liquid subsides, the plug member is lowered away from the drain port to the open valve position and a lower part of the probe means, having moved with the plug member, extends through the valve discharge passageway to push away debris and preclude blockage. 
     Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and of embodiments thereof, from the claims and from the accompanying drawings in which each and every detail shown is fully and completely disclosed as a part of this specification in which like numerals refer to like parts. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view of one embodiment of the improved drainage valve of this invention; 
     FIG. 2 is an exploded view of the drainage valve depicted in FIG. 1; 
     FIG. 3 is a sectional elevational view of another embodiment of the improved drainage valve of this invention; and 
     FIG. 4 is the bottom view of the improved drainage valve depicted in FIG. 3. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail a preferred embodiment of the invention and modifications thereof, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. The scope of the invention will be pointed out in the appended claims. 
     FIG. 1 and 2 show an improved drainage valve 10 incorporating the present invention adapted to use for draining the fluids from the interior of a burial casket 12. The drainage valve 10 is located in the floor portion 14 of the burial casket 12 and is mounted to the floor portion 14 with a flange 16. The drainage valve 10 includes a top member 18 integral with the flange 16 and which contains a drain port 20. Depending downward from the top member 18 is a housing 22 which includes interior walls 24 and defines the valve chamber 26. A retaining plate 28 extends across the bottom of the housing 22. The retaining plate 28 defines a plurality of apertures 32 for passage of fluids therethrough. A cup-shaped plug member 30 is located within the valve chamber 26 freely disposed for vertical and horizontal movement therein and for normally maintaining the drain port 20 open by assuming a lower position in the valve chamber 26 under the influence of gravity for the drainage of fluids therethrough. The plug member 30 is retained in the valve chamber 26 by the retaining plate 28. In addition, the retaining plate 28 prevents the passage of exterior bulk debris into the valve 10 by limiting the passage into the valve 10 through the apertures 32. 
     The plug member 30 includes probe means 33 which is shown as having an upper probe rod 34 which extends through the drain port 20 for clearing derbis from the drain port 20 and precluding blockage thereof in response to movement of the plug member 30 into the drain port 20. 
     Probe means 33 further comprises a lower probe rod 36 which extends through a selected aperture 32 in the retaining plate 28 for clearing debris from the aperture 32 and precluding blockage thereof in response to movement of the plug member 30 away from the drain port 20. 
     By the arrangement shown in FIGS. 1 and 2, liquid flowing into the drainage valve 10 through the retaining plate 28 as a result of a rising liquid or water table, will cause the plug member 30 to move vertically upwardly against the force of gravity due to the buoyancy created by the formation of an air pocket within the cup-shaped plug member 30. This will seat the upper surface of the plug member 30 in line contact with the edge of the drain port 20 to close the drain port 20 and prevent liquids from flowing through the valve 10 into the interior of the burial casket 12. As the liquid level subsides, the plug member 30 is lowered away from the drain port 20 permitting fluids to flow from the interior of the burial casket 12 through the drain port 20 and out of the valve 10. The intermittent movement of the plug member 30 in the vertical direction upwardly and downwardly permits the upper probe rod 34 and the lower probe rod 36 to extend through the drain port 20 and one of the apertures 32 respectively, to push away debris and preclude blockage. 
     FIGS. 3 and 4 show an improved drainage valve 37 located and adapted for use in a container 38 which is placed in an environment where it is subjected to intermittent rising levels of liquid. The rising liquid level is sometimes below and sometimes above the bottom 40 of the container 38 and drainage valve 37. The container 38 is shown in FIG. 3 with an orifice 42 in the bottom 40 of the container 38 to permit the drainage of fluid from the container. A top member 44 is secured to the bottom of the container 38 by a flange 46. The top member 44 contains the drain port 48 located in the orifice 42. The drain port 48 presents a seating surface 50 towards spherical plug member 52. The plug member 52 is retained below the drain port 48 by retaining means 54. The retaining means are shown as three posts oriented 120° apart around the spherically shaped plug member 52 and retain the plug member 52 in the valve 37. The plug member 52 is buoyant with respect to the liquid. As the liquid level rises the buoyant plug member 52 is forced into the drain port 48 and the seating surface 50 thereby closing the valve and preventing the rising liquid from backflowing into the container 38. An upper probe rod 56 is secured to the plug member 52 for pushing away from the drain port 48 any debris which may be blocking the drain port. A lower probe rod 58 and peripheral probe rods 60 project through the retaining means 54 and moves vertically upward and downward between the retaining means in response to the liquid level. This acts to push debris away from the retaining means 54 and precludes blockage of fluid out of or into the retaining means. 
     The upper probe rod 56 described above and depicted in FIGS. 1 and 3 and 33 and 56 respectively, could take other shapes. For instance, in FIG. 1 the top of the plug member 30 could be constructed to form a raised projecting top that would extend through the drain port 20. Similarly, the lower probe rod 36 could take other shapes. For example, the bottom edge of the plug member 30 could be constructed to form projections through one or more of the apertures 32 which would act to push debris away from the apertures 32. 
     Thus, it may be seen that a compact non-return drainage valve can be provided with a self-cleaning plug and port assembly which will provide the above described desired functions and will overcome the problems heretofore experienced with drainage valves in burial caskets or other containers. 
     From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the true spirit and scope of the novel concept of the invention. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.