Abstract:
A valve assembly for preventing backflow and siphoning in a plumbing line, the valve assembly comprising a valve body including a first end having a first aperture for receiving liquid from a supply source, a second end having an exit port for releasing liquid to a demand source, and a second aperture for receiving air. The assembly further includes a variable thickness diaphragm located within a valve chamber having a first and a second portion, the first portion for influencing the flow of liquid in the first aperture and the second portion for influencing the flow of air in the second aperture, the second portion having a flex line for enhancing the amount of flexing provided by the second portion. The first portion further includes a protuberance for enhancing the strength of the diaphragm during low vacuum sealing conditions.

Description:
TECHNICAL FIELD 
       [0001]    The present invention concerns a fluid valve structure, more specifically, a valve used in a fluid-feed line that is resistant to both backflow and siphon conditions. 
       BACKGROUND ART 
       [0002]    The valve structure of the present disclosure is in the category or class of valves which are adapted to insertion in a fluid-feed line between a nozzle or discharge orifice and the fluid supply from which fluid is drawn. Such a valve can be used in a multiplicity of lines and is especially adaptable, but not limited to residential fluid systems, self-contained fluid systems and systems having limited space. 
         [0003]    The valve herein is described in the context of the utilization of water systems which are found in residential applications, manufactured homes, and recreational vehicles, and is applicable to any system which incorporates a flexible hose connection, whether it be found in a shower, wash basin, bath tub, or the like. The valve of this structure is especially useful in such an environment incorporating fluid systems having a closed or self-contained water supply source from which all utilization of water derives. 
         [0004]    There is a heightened concern surrounding the contamination of residential water supply, and especially for self-contained water supply systems. As a result, such systems are subject to rather stringent sanitary codes, which require an insertion in the supply line of valves designed to prevent backflow or re-entry of liquids or solids into the system supply. Backflow is the reversal of the normal and intended direction of flow of water in a pipe line. Siphonage or back siphonage occurs when water in a supply line produces a flow of water in a direction opposite the path of normal flow because of below atmospheric pressure in the supply system. 
         [0005]    Valves designed to achieve this result, often referred to as vacuum breaker valves have been in use for several years, and are associated with or capable of permitting the entry of air into the water line under conditions that would otherwise create a siphon condition. In such valves, many complex designs have been used in order to open and close such air vents and to prevent the fluid from leaking through the air vents. An example of such a valve is demonstrated in U.S. Pat. No. 3,951,164. 
         [0006]    Increased sanitary code requirements, in particular American Society of Sanitary Engineers “ASSE” section  1014 , the performance requirements for hand-held showers (hereinafter “the Code”) have made many, if not all, existing valve designs incapable of passing certification tests under the new provisions. The Code requires a valve that prevents backflow of water when a vacuum pressure is applied to the outlet end of the valve ranging between six (6) inches to twenty-four (24) inches of mercury. Further the Code requires there to be no back-siphonage of water from downstream piping into the supply piping when the check valve seat or disc is fouled to a partially open position by debris, which is simulated in the certification test by a 0.032″ diameter wire while the outlet side of the valve is under a vacuum. 
         [0007]    An example of a vacuum breaker valve incapable of satisfying the relatively recent Code requirements is demonstrated in U.S. Pat. No. 4,953,584 issued to Lajos Vegso. The valve found in &#39;584 patent includes a diaphragm having a uniform thickness that is unable to accommodate the flexibility needed for the unrestricted flow of fluid while remaining rigid enough to prevent the collapse of the diaphragm when being subjected to the vacuum levels required by the Code. The &#39;584 patent further fails to provide the needed flexibility in the diaphragm or pressure assistance from either air or liquid when debris is simulated by the 0.032″ diameter wire. 
         [0008]    What is needed is an improved vacuum breaker valve assembly capable of satisfying the requirements of the Code as discussed above, resistant to both backflow and back-siphonage. 
       SUMMARY OF THE INVENTION 
       [0009]    The siphon and backflow resistant valve concerns an assembly having a valve body that includes a first end with a first aperture for receiving liquid from a supply source, a second end having a port for releasing liquid to a demand source, and a second aperture for receiving air. The valve assembly also includes a valve chamber located within the valve body that at least a portion of the chamber is enclosed by a cap assembly. The valve assembly further concerns a variable thickness diaphragm that is located within the valve chamber having a first and a second portion, where the first portion influences the flow of liquid from the first aperture and the second portion influences the flow of air from the second aperture. The diaphragm also includes a flex line for enhancing the amount flexing produced by the second portion. 
         [0010]    In one embodiment, the flex line is a linear section extending along the diaphragm. In this embodiment the flex line is a segment of the diaphragm having a reduced cross-sectional area. In a separate embodiment, the flex line reduces the cross-sectional area of the second portion along the flex line by approximately 50 percent. 
         [0011]    In another embodiment, the first portion of the diaphragm includes a projection or protuberance for adding strength to the diaphragm during low vacuum conditions. The projection is integral to, and extends from the diaphragm adding as much as twice the material thickness in a prescribed area. In this embodiment, the projection is circular, but can assume other geometrical configurations without departing from the spirit or scope of the invention. The geometrical strength to the diaphragm concerns only a single condition, that is when the first portion assumes a closed position. During this low vacuum condition, the projection prevents the collapsing of the first portion, yet the first portion&#39;s surrounding material thickness is reduced to prevent air and debris from passing around the inlet orifice. 
         [0012]    In one embodiment the diaphragm has a durometer range between 35 and 45. In the illustrated embodiment, the diaphragm durometer value is approximately 40 and is made from Ethylene Propylene Diene Monomer “EPDM” rubber, and has a variable thickness over the entire diaphragm ranging between 0.010 and 0.030 inches. 
         [0013]    According to a feature of one embodiment, the cap assembly includes a securing member having a width less than the inner diameter of the valve chamber. As such, the air or liquid within the chamber can assist in the sealing engagement produced by the diaphragm. The securing member further provides a coacting arrangement with an abutment portion on the diaphragm for embracing the diaphragm to the valve chamber. 
         [0014]    These and other advantages and features of the exemplary embodiments of the siphon and backflow resistant valve are described in detail in conjunction with the accompanying drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a first perspective view of the siphon and backflow resistant valve; 
           [0016]      FIG. 2  is a second perspective view of the valve in  FIG. 1 ; 
           [0017]      FIG. 3  is a side view of the valve in  FIG. 1 ; 
           [0018]      FIG. 4  is a first end view of the valve in  FIG. 3  along line  4 - 4 ; 
           [0019]      FIG. 5  is a second end view of the valve in  FIG. 3  along line  5 - 5 ; 
           [0020]      FIG. 6  is an exploded sectional view of the valve in  FIG. 5  along section line  6 - 6 ; 
           [0021]      FIG. 7  is an assembled sectional view of the valve in  FIG. 5  along section line  7 - 7 ; 
           [0022]      FIG. 8  is a plan view of a cap assembly; 
           [0023]      FIG. 9  is a first end view of the cap assembly of  FIG. 8 ; 
           [0024]      FIG. 10  is a second end view of the cap assembly of  FIG. 8 ; 
           [0025]      FIG. 11  is a sectional view of the cap assembly of  FIG. 10  along line  11 - 11 ; 
           [0026]      FIG. 12  is a plan view of a flexible diaphragm; 
           [0027]      FIG. 13  is a side view of the flexible diaphragm of  FIG. 12 ; 
           [0028]      FIG. 14  is an operational view depicting the valve operation during a flow of liquid past the flexible diaphragm with a cover portion assuming an open position; and 
           [0029]      FIG. 15  is an operational view depicting the valve operation during a flow of air past the flexible diaphragm with the cover portion assuming a closed position to prevent siphoning or backflow. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    The description of the preferred embodiments is directed to a siphon and backflow resistant valve assembly  10 , depicted in  FIGS. 1 and 2 . The valve assembly includes a generally tubular body  12 . As best seen in  FIG. 2 , an inlet nipple  15  extends from, and formed integrally with the valve body  12 , and includes a plurality of flats  17  suitable for engaging a tool for tightening the nipple to a plumbing fitting. The nipple portion  15  of the valve assembly  10  further includes external threads  19  for mating the nipple portion with the plumbing fitting. Examples of plumbing fixtures adaptable to plumbing nipples or fittings can include a shower, wash basin, bath tub, and the like. In the illustrated embodiment, the external threads  19  are ⅛-27 NPT, but could be any thread size suitable for providing a sealable engagement with a plumbing fixture. 
         [0031]    At an end on the valve body  12  opposite the nipple  15  is a main valve chamber  16  as best seen in  FIGS. 4 and 6 . A generally tubular wall  14 , a bottom wall  20 , and a cap assembly  30  form the valve chamber  16 . The cap assembly  30  is shown in FIGS.  1  and  6 - 11  and is positioned within a recess or counter bore  22  of the valve body  12 . The bottom wall  20  includes a plurality of air apertures  21  that under certain conditions, as described below, allow air to flow into the main valve chamber  16 . In the illustrated embodiment, three air apertures are used, each aperture having diametrical opening approximately ranging between 0.060″- 0 . 090 ″ and in one preferred embodiment the aperture diameter is 0.085″. 
         [0032]    Extending through the nipple portion  15 , tubular wall  14 , and into the valve chamber  16  is an inlet orifice  11  for receiving the flow of fluid from the plumbing fitting (not shown) into the valve chamber  16  under certain conditions. In one preferred embodiment, the inlet orifice  11  has a diameter of approximately 0.150″. External threads  18  surround the exterior portion of the tubular wall  14  such that the valve assembly  10  can be adapted to a corresponding plumbing fitting. In one preferred embodiment, the external threads  18  are ½-14 NPSM threads, but could be any size having a suitable thread to provide a sealing engagement with the plumbing fitting. Located substantially in-line with the inlet orifice  11  is an outlet orifice  13 , which is located within the cap assembly  30 . The alignment between the orifices  11  and  13  can be accomplished by any number of structures known to those skilled in the art. In the illustrated embodiment, alignment is achieved by a key  24   a  located in tubular wall  14  that corresponds to keyway  24   b  in the cap assembly  30 . The alignment is further facilitated by guides  23   a  and  23   b , which corresponds to projections  33 , represented individually by  33   a  and  33   b , respectively. 
         [0033]    Referring now to  FIGS. 6 and 7  are cross sectional views of the valve assembly  10 .  FIG. 6  depicts an exploded assembly view having the cap assembly  30 , and a flexing member or diaphragm  40  assembled within the main valve chamber  16  of valve body  12 . The diaphragm  40  is secured between the cap assembly  30  and valve body  12  at the bottom wall  20  through plate member  32 , which is in contact with an abutment portion  41  located on the diaphragm shown in  FIG. 7 . 
         [0034]    The diaphragm  40  is designed having a variable thickness as revealed in the side view of  FIG. 13 . In one preferred embodiment, the diaphragm is made from a material having a 35-45 durometer range. In the illustrated preferred embodiment, the diaphragm is made from Ethylene Propylene Diene Monomer “EPDM” rubber having a durometer value of approximately 40. The diaphragm could be made from other materials having similar characteristics without departing from the spirit and scope of the claimed invention. The abutment  41  is centrally and symmetrically located about the generally circular diaphragm  40 , dividing it into a first and second section  40   a  and  40   b , respectively as depicted in  FIG. 12 . A first  43  and second  44  lobe portion extends along the first section  40   a , which assist in the placement of the diaphragm within the valve chamber  16 . A cover portion  45  extends from the first section  40   a , and is aligned within the valve chamber  16 . The cover portion  45  when located within the valve chamber is positioned over the inlet orifice  11 . When liquid is flowing, by virtue of a user turning a conventional valve in the plumbing fitting, the cover portion  45  is displaced allowing the liquid to pass into and throughout the chamber  16 , eventually exiting through the outlet orifice  13 . 
         [0035]    In operation the cover portion  45  and second section  40   b  transition between an opened and closed position as depicted in  FIGS. 14 and 15 . The cover portion  45  is displaced to an open position in  FIG. 14  and assumes a normally closed position in  FIG. 15 . Situated on, and integral to the cover portion  45  is a circular protuberance or boss  46 . The novel design of boss  46  is to prevent the cover portion  45  from collapsing into the inlet orifice  11  during vacuum conditions occurring in operation or during Code certification tests. Preventing the collapse of the cover portion  45  provides reassurance that backflow or siphoning conditions in the valve  10  have been avoided. The variable thickness of the diaphragm, in particular the relatively reduced cross sectional areas of the first and second sections  40   a  and  40   b  allows for improved sealing properties with the inlet orifice  11  and apertures  21 . 
         [0036]    The boss in one preferred embodiment includes a thickness slightly greater than the cover portion  45 , which in this embodiment is approximately 0.010″. Therefore, the additional material from the boss  46  provides a stack-up thickness in the strengthened area between 0.020″ and 0.030″. The boss  46  in the illustrated embodiment is annular having a diameter of approximately 0.100″, but could assume other geometries without departing from the scope or spirit of the invention. A pair of gaps of approximately 0.060″ between the first and second lobe portions  43 ,  44  and the cover portion  45  provide a propitious level of flexibility to the cover portion in combination with the added geometrical strength of boss  46  that is suitable for anti-siphoning backflow operation. 
         [0037]    Turning now to the area opposite the cover portion  45  of the abutment  41  is the second section  40   b  of the diaphragm  40 . The second section  40   b  covers apertures  21 , which under certain conditions raise the second section, thereby providing air throughout the main valve chamber  16 . Air is permitted to enter the chamber  16 , as shown in  FIG. 15  when pressure downstream from the valve is less than the pressure in the chamber, creating a low vacuum condition that is highly susceptible to siphoning and backflow. The configuration of the diaphragm&#39;s second section  40   b  is specifically designed for enabling the admission of air at heightened siphoning/backflow conditions during the valve  10  operation and for Code compliance. The air admission criteria in the diaphragm  40  was achieved by designing a line of weakness  42 , as best seen in  FIGS. 12 and 13 . The line  42  acts like a hinge allowing the displacement of the second section  40   b  as air enters the main valve chamber  16  during vacuum conditions. In one embodiment, the line of weakness  42  is a reduction in the cross-sectional area of the second section  40   b . In another embodiment, the line of weakness is a 60° (represented by angle β in  FIG. 13 ) fillet extending from the abutment  41  with a 0.010″ radius into a second section  40   b . The material thickness of the second section in this embodiment is 0.030″ therefore the fillet removes approximately half the material from the cross section. 
         [0038]    In operation, liquid passes through inlet orifice  11  displacing the cover portion  45  to an open position represented in  FIG. 14 . The liquid fills the entire main valve chamber  16  such that liquid passes to both sides of plate member  32 , thereby adding pressure against the second portion  40   b . Flow throughout the main valve chamber  16  is made possible since the width of the plate member  32  is less than the inner diameter of tubular wall  14 . The additional pressure by the liquid against second portion  40   b  while in a normally closed position in addition to its reduced thickness, reassures a sealing engagement is occurring between the diaphragm  40  and apertures  21 . The termination of the flow of liquid at the plumbing fitting creates a heighten opportunity for a low vacuum condition. Assuming a low vacuum condition occurs, the force of air from the atmospheric pressure outside the valve acts on the second section  40   b  of the diaphragm  40  through apertures  21 . The pressure over the surface area of the apertures  21  produces a cantilever force that raises the second section  40   b  by pivoting about the line of weakness  42  displacing the section from its normally closed position. As the second section is displaced, the air passes throughout the main valve chamber and produces pressure against the cover portion  45 . It has been determined in one preferred embodiment that three apertures  21  each having a 0.085″ diameter provide enough pressure for preventing backflow in siphoning conditions. The pressure against the cover portion  45 , in addition to the diaphragm&#39;s reduced thickness provides reassurance that an antisiphon/backflow sealing engagement occurred between the cover portion and the bottom wall  20 . The boss  46  provides additional strength to the cover portion in one direction to prevent failure of the sealing engagement or collapsing during low vacuum conditions or during Code certification testing, while offering no additional strength in a second direction thereby allowing the maximum liquid flow conditions to occur. 
         [0039]    It will be understood that various modifications can be made without departing from the spirit and scope of the claimed invention.