Patent Publication Number: US-8118053-B2

Title: Adjustable backflow prevention device

Description:
PRIORITY CLAIM 
     The present application claims priority to U.S. Provisional Application Ser. No. 61/059,915, filed Jun. 9, 2008 and entitled “ADJUSTABLE AIR GAP BACKFLOW PREVENTION DEVICE AND DRAIN ADAPTER”, which is herein incorporated by reference in its entirety. 
    
    
     FIELD OF INVENTION 
     The present invention relates generally to backflow prevention devices and, more particularly, to a plumbing fixture for attachment to a sewer connection or drain and that receives one or more appliance or equipment drain lines for preventing backflow by interposing an air gap in between. 
     BACKGROUND OF INVENTION 
     There is an inherent danger in connecting the drain lines of equipment and appliances directly to a building&#39;s main drain or sewer pipe. This is because the potential of backflow of sewer fluids through the drain lines into the equipment or appliances can contaminate the equipment or, worse, allow entry of the sewer into the public water supply. Such backflow can be caused by an unexpected increase in liquid pressure in the sewer system or an unexpected decrease of the liquid pressure in the drain line. For this reason, many state and local governments have established codes that must be complied with before an equipment drain can be connected to the sewer system. Such codes typically require that an air gap be established between each equipment drain line and the sewer system to prevent backflow. This air gap creates an indirect drain line between the equipment or appliance and the main sewer line. The discharge line must dispose of its liquid waste by discharging into a plumbing fixture which itself is connected to the building drainage system. The plumbing fixture most generally provides an air gap between the equipment or appliance drain line and the drain standpipe, grid or hub which is connected to the building drainage or public sewer system. 
     The prior art includes devices to provide the needed air gap and/or prevent backflow. Much of the prior art consists of complicated devices employing valves with moving parts, or baffled chambers requiring machined parts. Some simpler air gap devices have entered the field such as the device disclosed in U.S. Pat. No. 5,860,444. These simple devices fail to meet the needs of many supermarkets, vending companies and restaurants, and homeowners, however, who require the ability to discharge multiple lines in a cost and space efficient manner as well as providing flexibility in how the fixture is attached to the building drain system. In addition, these simple devices still require use of a specifically sized device for each drain line. 
     SUMMARY OF INVENTION 
     An adjustable backflow prevention device can be installed between various equipment drain lines and a drain cover or drain pipe. The backflow prevention device provides an air gap operable to prevent backflow of sewer waste into the equipment lines. The device includes a drainage hub and tubing mount. The drainage hub can have an upper funnel portion and lower pipe portion that define a liquid flow conduit running therethrough. The funnel upper edge can have a flange with a rim defining an upwardly facing mounting surface. The tubing mount or bracket can attach to the drainage hub at the mounting surface. The tubing mount can have a mount base and a mount cap that define a plurality of drain line mounting slots. The mount base and mount cap can be connected with threaded members to define a clamp mechanism for securing the drain lines. The mount can have a plurality of drain line receiving slots that allow attachment of different size discharge tubing lines. The mount can be adjustably attachable at multiple positions around the rim by a series of holes along the flange. A singe tube mount or a plurality of mounts can be attached to the flange. The drainage hub can be sized for direct bonding to a standard drain pipe. Alternatively, a J-shaped hook that can be attached to a central boss supported in the flow conduit by cross supports can be used to attach the back flow device to a drain grid. The tubing mount supports the drain lines in such a way that the drain line effluent is positioned to be in fluid connectivity with the upper opening of the liquid flow conduit. 
     It is a feature and advantage of certain embodiments of the present invention to provide a backflow prevention device which is simple, compact and easy to install. 
     It is a feature and advantage of certain embodiments of the present invention that the same backflow prevention device may be used for multiple sizes and types of drain lines. 
     It is further a feature and advantage of certain embodiments of the present invention that a single backflow prevention device may be used for multiple drain lines at one time. 
     It is a further feature and advantage of certain embodiments of the invention that it can be directly attachable to a drain grid or cover. 
     It is also a feature and advantage of certain embodiments of the invention that it is attachable to a standard standpipe, and easily adaptable to attachment to any size standpipe with standard pipe fittings. Moreover, certain embodiments provide for both the direct attachment to a drain grid or cover as well as providing an internal diameter for connection to the end and exterior of standard plumbing PVC pipe. Thus, flexibility is offered by a single device in how the fixture may be attached to the building drain system. 
     It is a feature and advantage that splash control is provided in the fixture. In certain embodiments a boss that is utilized for attachment of a j-shaped hook for securement to drain grids or covers is centrally supported by flutes or webbing within the fixture. The flutes or webbing also effectively provide splash control as well as a barrier to external objects entering the fixture and the connecting drain. 
     It is a further feature and advantage that a tubing mount provides a simple clamping mechanism for securing multiple drain lines. Moreover, the tubing mount may be chordally mounted positioning a plurality of parallel discharge lines aligned with a diameter of the funnel portion. Moreover, the tubing mount may have other shapes such as arcuate to follow the shape of the flange or may be circular with one or more drain overflow passageways. The tubing mount may be adjustable around the entire periphery of the flange of the funnel portion of the fixture. Moreover, multiple tubing mounts can be mounted to the top flange of the funnel providing multiple attachment sites and accommodating lines from different directions. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a backflow prevention device according to an embodiment of the present invention. 
         FIG. 2  is a side elevational view a backflow prevention device according to an embodiment of the present invention with a partial cross-section showing the invention attached to a drain grating. 
         FIG. 3  is an exploded perspective view of a backflow prevention device according to an embodiment of the present invention. 
         FIG. 4  is a top plan view of a backflow prevention device according to an embodiment of the present invention. 
         FIG. 5  is a cross sectional view of the drainage hub portion of the device of  FIG. 4  bonded to a standard plumbing pipe and taken at line  5 - 5  of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Referring to  FIGS. 1 through 5 , a backflow prevention device  10  generally comprises a drainage hub  12 , a tubing mount  20  and a fastening device  14 . Drainage hub  12  may consist of a funnel shaped portion  11  and a lower pipe portion  13 . Drainage hub  12  is generally connected to a drain or pipe as shown in  FIG. 2  or  FIG. 5 . This connection may be accomplished in one of two ways. Drainage hub  12  can be directly connected to a drain or sewer cover through the use of a fastening device  14  such as a J-shaped hook. Installation of device  10  may also occur through lower portion  13  being conventionally bonded to the sewer or drain system such as by use of solvent welding, adhesives, threads, or the like. 
     Drainage hub  12  has a flange with an upper rim  16  having a mounting surface  17 , to which tube mount  20  is attached. The body of drainage hub  12  has a central opening  26  that runs from upper rim  16  through lower portion  13  that defines a liquid flow conduit. Upper rim  16  preferably has holes  18  that can be used to attach tube mount  20  to drainage hub  12  using conventional means such as a nuts and bolts or self tapping screws. Alternate sizes of holes may be provided. The plurality of holes  18  allows for the attachment of a plurality of tube mounts  20  and allows adjustability in positioning of the tube mount  20  or mounts around the mounting surface  17 . Thus, an advantage and feature is that the device can be used with a plurality of discharge drain lines  32  as well as discharge lines coming from different directions, and tube mount  20  can be positioned or repositioned to better fit within a given space after drainage hub  12  has been attached to the sewer system. 
     Tube mount  20  has a base  21  and cap portion  22  and allows for the easy installation of backflow prevention device  10  for use with multiple drain lines. The upper edge of tube mount base  21  can have U-shaped indents or slots to cradle and support multiple drain lines at once as shown in  FIG. 2  with drain line  32 . Tube mount  20  supports drain lines above central opening  26 . Mount cap portion  22  in conjunction with fasteners, such as screws or nuts and bolts, are used to clamp the drain lines  32  in place. Mount cap  22  can also have indentations on its lower edge mirroring those on the upper edge of tube mount base  21 . Together the indents on mount cap  22  and mount base  21  cooperate to secure drain discharge lines so that they can discharge into drainage hub  12  of backflow prevention device  10 . Fastener  24  is used to hold mount cap  22  securely connected to mount base  21 . Fastener  24  is preferably a screw or a nut and bolt combination. The use of a nut and bolt or similar device for fastener  24  to connect mount cap  22  and mount base  21  allows device  10  to be used with drain tubes of varying sizes without the need to substitute pieces. Tube mount  20  maintains a spaced relationship between the drain lines  32  discharging into drainage hub  12 . The height selected for tube mount  20  determines the preset vertical air gap G between drain lines  32  and drainage hub  12 . Other attachment methods may be used to secure the tubing mount to the drainage hub flange. For example C-shaped clamping structure could snap onto cooperating structure on the rim eliminating the need for screws. Attachment pegs with interference fits and resilient pieces could be integral with the tube mount to be inserted into apertures on the hub flange. 
     The drainage hub  12  and the tube mount  20  can preferably be formed through injection molding. They are typically formed of an inexpensive plastic useful in plumbing applications, such as polyvinylchloride (PVC). Use of this type of material permits the device to be adhesively, or otherwise liquid tightly connected to the sewer system. Alternatively, drainage hub  12  and tube mount  20  can be formed using any other plastic molding process and can be formed of any other plastic material. 
     Grate fastening device  14  can be attached to backflow prevention device  10  though webbing or cross supports  28 . Cross supports  28  are integrally formed with drainage hub  12  during injection molding of drainage hub  12 . A boss  38  is supported by the webbing and has an aperture to permit a threaded J-hook to extend therethrough. The threaded J-hook may be hooked onto a grating  50  of a floor drain  52 , as illustrated in  FIG. 2 . 
     A drain discharge line  32  is illustrated in  FIG. 2  with the tube mount  20  to form a preset vertical gap G between the discharge drain lines  32  and the drainage hub  12 . To facilitate escape of sewer waste in the event backflow occurs, air gap G extends substantially around the circumferential extent of upper rim  16  of drainage hub  12 . In the preferred embodiment, tube mount  20  has two legs with an opening in between to provide an overflow volume which is circumferentially as large as possible while maintaining the ability to support multiple discharge lines. 
       FIG. 3  is an exploded view of backflow prevention device  10 . Nuts  30  and  34  along with washer  33  can be used such that fastening device  14  attaches backflow prevention device  10  to a drain grid without the removal of the drain grid and without risking the loss of fastening device  14  by dropping it through the drain grid. Nuts  30 ,  34  can be loosened enough that fastening device  14  can be maneuvered through the grids of the drain, but not so loose that it can separate completely from drainage hub  12  and fall into the sewer system. After the fastening device  14  has been threaded below the grid, nuts  30 ,  34  are tightened until lower end  13  of the drainage hub  12  and the sewer grate are secured together. 
       FIG. 4  is a top down view of drainage hub  12  showing the configuration of the cross supports  28  configured as flutes or webbing. Boss  38  can be positioned at the intersection of the two such cross supports  28 . Screws  36  can be used to attach the tube mount  20  to the upper rim  16 . The use of a screw  36  or other non-permanent fastening system allows for the flexibility to reposition the tube mount  20  with ease to better fit in the specific location. Moreover, the flange and upper rim with aperatures extending all the way around the rim allows additional tube mounts  20 . 1  to be attached. Thus drain tubing coming from different directions can be easily accommodated. 
       FIG. 5  is a cross-sectional view of drainage hub  12  cut along line  5 - 5  of  FIG. 4 . The figure shows the location of cross support  28 , above the portion of drainage hub  12  pipe portion  13 . The lower portion  13  of drainage hub  12  has a diameter sized such that drainage hub  12  can be attached, through means such as conventional bonding, to a standard pipe for example on a drain stand  56 . J-shaped hook  14  may be removed in such an application. The drain pipe nipple  57  may engage an inside diameter and abut a shoulder  62  within the fixture. The inside diameter is sized to conform to standardized PVC pipe. For example it may be sized at 2.39 inches to fit on standard 2 inch pipe having an outside diameter of 2.375 inches. 
     The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered by the spirit and technical theory of the subject invention.