Abstract:
A unitary diaphragm assembly for use primarily in conventional flush valves. The diaphragm assembly has a flexible diaphragm which includes a sealing portion and a mounting portion at the outer peripheral edge. A flow ring is positioned adjacent the sealing portion of the diaphragm. An elongated barrel member extends from the diaphragm in a longitudinal direction and includes a plurality of radial guides positioned circumferentially around the outer surface of the barrel member along a portion of the length of the barrel member. The diaphragm defines an orifice having a ring portion that flexes when a pressure difference is applied across the orifice thereby increasing the flow rate across the diaphragm. The orifice has a smaller diameter at a first end relative to a second end of the orifice. A method of compensating for a pressure difference across the diaphragm is also disclosed.

Description:
CROSS-REFERENCED TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/094,994 filed Jul. 31, 1998, entitled “Diaphragm Orifice for Flushometer”. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates in general to flush valves for water closets, urinals and other plumbing equipment. More particularly, the invention relates to an improved diaphragm for use in flush valves. 
     2. Description of the Prior Art 
     Flush valves in water closets, urinals and other plumbing devices which utilize a flexible diaphragm to establish and to seal off the connection between the inlet and outlet are well-known in the art. Typically, the diaphragm is made of an elastomeric material, such as rubber, and includes a bypass which provides fluid communication between the inlet side of the flush valve and an upper chamber of the flush valve. A typical prior art diaphragm is shown in FIG. 1 of U.S. Pat. No. 5,232,194 to Saadi et al. (hereinafter “the Saadi patent”), and is incorporated herein by reference. 
     The Saadi patent also discloses a unitary diaphragm assembly that includes a diaphragm having a cylindrically-shaped bypass orifice formed therein and is illustrated in FIGS. 2 and 3 of the present patent application. 
     The performance of prior art diaphragms varies depending on the pressure drop between the opposite sides of the diaphragm due to the bypass orifice. Specifically, a higher pressure difference across the diaphragm, such as will occur on a bottom floor of a multistory building, causes more water to pass through the flush valve for a fixed period of time when the flush valve is activated. Likewise, in a situation where there is a low pressure difference across the diaphragm, less water will flow through the flush valve when it is activated. Hence, the amount of water flowing through the flush valve is a function of the supply of water pressure to the flush valve. 
     Therefore, it is an object of the present invention to provide an improved diaphragm orifice to compensate for pressure differentials across the diaphragm and improve valve performance. 
     SUMMARY OF THE INVENTION 
     The present invention is a barrier for separating fluid and is configured to have a pressure difference applied across the barrier. The barrier includes a flexible diaphragm having a first side and a second side and defines an orifice extending from the first side to the second side. The orifice has a first end defined in the first side and a second end defined in the second side of the diaphragm. The first end has a diameter less than the diameter of the second end. The second end of the diaphragm is concave and the first side of the diaphragm is convex when the pressure difference is applied across the barrier whereby the diameter of the first end increases. 
     The present invention is also a diaphragm orifice for a valve such as a flush valve. The flush valve made in accordance with the present invention generally includes a valve body defining an inlet connection and an outlet connection, and a unitary diaphragm assembly positioned in the valve body. The unitary diaphragm assembly separates and seals off the inlet connection from the outlet connection. The unitary diaphragm assembly is configured to have a pressure difference applied across the assembly. 
     The unitary diaphragm assembly further includes a flexible diaphragm. The flexible diaphragm has a mounting portion at a peripheral edge for mounting the diaphragm assembly within the flush valve. The diaphragm has a first side and a second side and defines an orifice extending from the first side to the second side. The orifice has a first end defined in the first side and a second end defined in the second side of the diaphragm. The first end has a diameter less than the diameter of the second end. The orifice extends from the first end to the second end. The second side of the diaphragm is concave and the first side of the diaphragm is convex when the pressure difference is applied across the assembly whereby the diameter of the first end increases. 
     The first end of the orifice is defined by a first portion of the diaphragm. The second end of the orifice is defined by a second portion of the diaphragm. The second portion is positioned adjacent the first portion. The first portion includes a tapered surface that preferably extends at an angle of about 45° from a horizontal plane passing through the diaphragm. Preferably the diaphragm is made of an elastomeric material, such as rubber or a thermoplastic elastomer resin, and is flexible. 
     The diaphragm of the unitary diaphragm assembly may be annular-shaped and may have a sealing surface. The unitary diaphragm assembly may further include a flow ring adjacent the sealing surface. An elongated barrel member may be formed adjacent the flow ring. The barrel member may have a first end or top end. A plurality of radial guides may be formed circumferentially around an outer surface of the barrel member and may extend along at least a portion of a longitudinal length of the barrel member. Additionally, the unitary diaphragm assembly may include a relief valve seat at the first end of the barrel member. The relief valve seat may be configured to seal against a relief valve of the flush valve. 
     In operation, a pressure difference across the diaphragm causes the diaphragm to flex. A greater pressure difference across the diaphragm will cause the diaphragm to flex more than a lesser pressure difference. The amount of flex affects the pressure sensitivity of the flush valve and improves the overall performance of the flush valve. Further, the flexing improves the flush valve&#39;s resistance to clogging. The flexing action can free debris that would normally clog a non-elastomeric orifice. Examples of this debris include sediment and water deposits such as scale. 
     The present invention is also a method of compensating for a pressure difference across the barrier discussed above. The method includes the steps of applying the pressure difference across the diaphragm and flexing the diaphragm. The pressure difference is applied such that pressure on the first side of the diaphragm is lower than the pressure on the second side of the diaphragm. The diaphragm is flexed such that the second side of the diaphragm is concave and the first side of the diaphragm is convex whereby the diameter of the first end increases and fluid flows through the orifice. The method may also include the step of positioning the diaphragm in the flush valve discussed above between the inlet connection and the outlet connection of the flush valve. 
     Further details and advantages of the present invention will become apparent from the following detailed description in conjunction with the drawings wherein like reference characters identify like parts throughout. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial sectional view of a prior art flush valve and conventional diaphragm assembly; 
     FIG. 2 is a perspective view of a prior art unitary diaphragm assembly; 
     FIG. 3 is a sectional view of the unitary diaphragm assembly shown in FIG. 2; 
     FIG. 4 is a perspective view of a unitary diaphragm assembly made in accordance with the present invention; 
     FIG. 5 is a sectional view of the unitary diaphragm assembly shown in FIG. 4; 
     FIG. 6 is a sectional view of a portion of the unitary diaphragm assembly shown in FIG. 5 with the diaphragm orifice in a first position; and 
     FIG. 7 is a sectional view of a portion of the unitary diaphragm assembly shown in FIG. 5 with the diaphragm orifice in a second position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Flush valves in water closets, urinals and other plumbing devices which utilize a flexible diaphragm to establish and to seal off the connection between the inlet and outlet are well-known in the art. FIG. 1 illustrates a typical prior art flush valve and diaphragm assembly. The flush valve has a hollow body  10 , generally made of brass, which includes an inlet connection  12 , an outlet connection  14  and a handle connection  16 . A barrel  18  is positioned within the flush valve such that the connection between the inlet  12  and the outlet  14  is through the barrel  18 . An annular main valve seat  20  is formed on a first or top end  21  of the barrel  18 . The annular main valve seat  20  is normally closed by a diaphragm  22  extending across the body  10  and defining an upper chamber  24 . The diaphragm  22  has a bypass  26  which provides fluid communication between the inlet side of the flush valve and the upper chamber  24 . The diaphragm  22  is attached at its outer edge to the valve body and is clamped in place by an annular clamping rim on an outer cover  11  of the body  10 . The diaphragm  22  has an opening which allows for fluid communication between the upper chamber  24  and the outlet  14 . A relief valve  28  normally closes the opening at the center of the diaphragm  22 . 
     The operation of the flush valve is generally as follows. In the normally closed position shown in FIG. 1, water pressure at the valve inlet is communicated to the upper chamber  24  through the bypass  26 . Since the surface area which is subjected to water pressure is greater on the upper side of the diaphragm  22 , the water pressure forces the diaphragm  22  down onto the main valve seat  20  preventing water from flowing to the outlet  14 . When the user moves a handle  30  in any direction, a plunger  32  moves inwardly tilting a stem  34  of the relief valve  28 . This releases the pressure in upper chamber  24  by allowing water to flow through a guide member  36 . With the upper chamber pressure relieved, the inlet water pressure forces the diaphragm  22  upwardly, off the main valve seat  20  allowing water to flow directly from the inlet  12  through the barrel  18  to the outlet  14 . When the diaphragm  22  and the relief valve  28  move upwardly, the relief valve  28  resets itself, closing off the upper chamber  24 . Water will then flow through the bypass  26  into the upper chamber  24  until the diaphragm  22  is again forced against the main valve seat  20 , thereby closing the valve. The guide member  36  moves with the diaphragm  22  and includes outwardly extending radial wing members  38  which engage the inner surface of the barrel  18  to guide the guide member  36  and the attached diaphragm  22  as the diaphragm  22  moves up and down. The diaphragm  22  defines a central passageway  39  (i.e., hole). The bypass  26  is radially spaced from the central passageway  39 . 
     FIGS. 2 and 3 show a prior art unitary diaphragm assembly  50 . FIG. 2 illustrates the unitary diaphragm assembly  50  which is designed to be utilized in flush valves of the type illustrated in FIG. 1, replacing the complicated diaphragm assembly of these devices. The unitary diaphragm assembly  50  is molded as a single piece from a thermoplastic elastomer resin or rubber. The unitary diaphragm assembly  50  includes a flexible and sealing diaphragm  52  which has a mounting portion  54  at an outer peripheral edge. The mounting portion  54  may be assembled into a “C” channel-type gasket. 
     With reference to FIG. 3, a sealing surface  56  is positioned at a generally radially inward position relative to the diaphragm  52  so as to cooperate with the main valve seat  20  of the flush valve. An annular support  58  extends upwardly from the diaphragm  52  above the portion of the diaphragm having the sealing surface  56 . Radial reinforcing ribs  60  extend between the upper end of a barrel member  68  adjacent a relief valve seat  62  and the annular support  58  to reinforce the annular support  58 , the relief valve seat  62  and the sealing surface  56 . The vertical legs of the ribs  60  maintain the relief valve  28  of the flush valve in position so that it may seal against the relief valve seat  62 . The reinforcing ribs  60  also extend to a flow ring  64  located on the barrel member  68  below the sealing surface  56  to add structural support for the flow ring  64 . 
     The relief valve seat  62  is positioned on the upper end of the barrel member  68 . The barrel member  68  is designed to cooperate with the barrel  18  of the flush valve and extends substantially coaxially along the length of the barrel  18 . The outer surface of the barrel member  68  is provided with radial guides  70 . The guides  70  engage the inner surface of the barrel  18  to maintain the unitary diaphragm assembly  50  in proper alignment as it moves up and down in the barrel  18 . The flow ring  64  controls the flow of water when the unitary diaphragm assembly  50  is in the open position. The guides  70  also provide structural support to the flow ring  64 . The guides  70  may extend substantially along the entire length of the barrel member  68 , as shown, for ease of manufacture. Alternatively, the guides  70  may extend only along a portion of the barrel member  68 . Additionally, the guides  70  may serve to support a supplemental flow control ring (not shown) which is positioned within the barrel  18 . 
     FIG. 3 also illustrates a modified mounting portion  54 ′ of the diaphragm  52 . The modified mounting portion  54 ′ has a greater thickness than the mounting portion  54  shown in FIG.  2 . This design eliminates the need for the “C” channel-type gasket. 
     The flow ring  64  includes a first stage  65  having a diameter larger than a second stage  66  which creates a steeped configuration of the flow ring. The size and shape of the flow ring  64  may be modified for different flush valve flow requirements. 
     The unitary diaphragm assembly  50  is also provided with a bypass orifice  72  which is defined in the diaphragm  52 . The unitary diaphragm assembly  50  is designed to operate in an analogous manner to the diaphragm assembly of the prior art as shown, for example, in FIG.  1 . 
     FIGS. 4 and 5 show a unitary diaphragm assembly  50  made in accordance with the present invention that is similar to that shown in FIG. 3 with the exception of the bypass orifice  72  being replaced by orifice  172 . In FIGS. 4 and 5, the unitary diaphragm assembly  50 , or diaphragm body, defines a central passageway  73  (i.e., hole). The orifice  172 , as shown in FIG. 4, is radially spaced from the central passageway  73 . 
     Referring to FIGS. 5-7, the diaphragm  52  of the diaphragm assembly  50  includes a first side  174  and a second side  176 . The first side  174  of the diaphragm  52  is a low pressure side of the diaphragm assembly  50  and the second side  176  of the diaphragm  52  is a high pressure side of the diaphragm assembly  50  when the flush valve is activated. The orifice  172  extends from the first side  174  to the second side  176 . The orifice  172  is defined in a portion  178  of the diaphragm  52 . The orifice  172  includes a first end or outlet end  180  and a second end or inlet end  182 . The first end  180  is defined by a first portion  184  formed in the diaphragm  52 . The second end  182  is defined by a second portion  186  which is formed in the diaphragm  52  adjacent the first portion  184 . The first portion  184  includes a ring portion  188  formed in the diaphragm  52 . The ring portion  188  is tapered at an angle from a horizontal plane P passing through the diaphragm  52  and defines a frusto-conical shaped portion of the orifice  172 . The second portion  186  of the second end  182  of the orifice  172  is cylindrical in shape. 
     Alternatively, the ring portion  188  can take other shapes and need not be tapered at all, but can be in the shape of an untapered ring having a diameter less than the diameter of the second portion  186 . In this embodiment, the diameter of the second end  182  is greater than the diameter of the first end  180 . 
     Referring to FIG. 6, a wall thickness of the first portion  184  is defined as the vertical distance between the plane P and the first side  174  of the diaphragm  52 . A thickness or height of the diaphragm  52  is defined as the vertical distance between the first side  174  and the second side  176 . The first end  180  of the orifice  172  also has a diameter A, as is discussed in detail hereinafter. 
     FIG. 6 shows the portion  178  of the diaphragm  52  containing the orifice  172  where pressures P 1  and P 2  on opposite sides of the orifice  172  are the same or approximately the same. Preferably, the ring portion  188  has an inner surface  190  that extends at an angle of about 45° from the horizontal plane P passing through the portion  178  when the pressure P 1  and P 2  on opposite sides of the orifice  172  are the same or approximately the same. The first portion  184  of the first end  180  may further include an untapered portion  192  formed in the first side  174  of the diaphragm  52 . The untapered portion  192  is formed in the diaphragm  52  adjacent the first portion  184  and meters the water through the orifice  172  for proper cycle time as discussed further hereinafter. 
     FIG. 7 shows the portion  178  of the diaphragm  52  containing the orifice  172  having a pressure difference ΔP (P 2 &gt;P 1 ) across the diaphragm, wherein the pressure P 2  adjacent the second end  182  is greater than the pressure P 1  adjacent the first end  180 . This condition exists immediately after the flush valve is activated and during the period of time thereafter when water flows through the orifice  172  until the diaphragm  52  is forced against the main valve seat  20  thereby closing the flush valve. Therefore, the first side  174  of the diaphragm  52  is the low pressure side of the diaphragm assembly  50  and the second side  176  of the diaphragm  52  is the high pressure side of the diaphragm assembly  50  when the flush valve is activated. 
     The diaphragm assembly  50  is intended to be positioned in the flush valve shown, for example, in FIG.  1 . The diaphragm assembly  50  is positioned in the valve body  10  and generally separates the inlet connection  12  and the outlet connection  14  and, preferably, seals off the inlet connection  12  from the outlet connection  14 . The diaphragm assembly  50  is thus a barrier between the inlet connection  12  and the outlet connection  14 , with the orifice  172  providing for fluid communication between the inlet connection  12  and the outlet connection  14 . The barrier, or diaphragm assembly  50 , has a pressure difference ΔP (P 2 &gt;P 1 ) across the barrier and, specifically, across the diaphragm  52  when the flush valve is activated, as discussed above. 
     As can be seen in FIG. 7, the ring portion  188  is flexed as a result of the pressure difference ΔP (P 2 &gt;P 1 ), thereby increasing the diameter of the first end  180  from A to B. In other words, at least a portion of the diameter of the orifice  172  increases due to the pressure differential ΔP. Additionally, the inner surface  190  now extends at an angle greater than about 45° from the horizontal plane P passing through the portion  178  as a result of the flexing of the ring portion  188 . The diaphragm  52  is therefore made of a thermoplastic elastomer resin or other similar material that permits flexing, such as rubber. The greater the pressure difference ΔP (P 2 &gt;P 1 ), the more the ring portion  188  flexes and the greater the diameter B becomes. The flexing of the ring portion  188  increases the flow rate across the diaphragm  52 . This, in turn, causes the flushometer valve&#39;s cycle time to decrease with increasing supply pressures. The faster cycle times affect the overall performance of the flush valve. In other words, the total volume of water flowing through the urinal or other flushing device for a given cycle remains relatively constant and is not a function of the water pressure. In particular, the lower the pressure difference ΔP (P 2 &gt;P 1 ) across the diaphragm  52 , which is indicative of the water supply pressure, the lesser the value of the diameter B. Further, the greater the pressure difference ΔP (P 2 &gt;P 1 ) across the diaphragm  52 , the greater the value of the diameter B. As the diameter B increases, the cycle time of the flush valve decreases so that a relatively consistent volume of water passes through the flush valve for a cycle irrespective of the water supply pressure. P 2  equals P 1  after the cycle is complete. A cycle is defined as the period of time from when the flush valve is opened until the flush valve is closed. 
     The untapered portion  192  also affects cycle time. The greater the diameter and the thickness of the untapered portion  192 , the greater the quantity of water will be metering or passing through the orifice  172 . Thus, the greater the diameter and the thickness of the untapered portion  192 , the greater the flow rate through the orifice  172 , which decreases the cycle time of the flush valve. 
     A suitable size of the diameter A is about 0.0201″ in the unflexed state of the diaphragm  52  shown in FIG. 6, and a suitable size of the diameter B is about 0.0264″ in the flexed state of the diaphragm  52  shown in FIG.  7 . The second end of  182  of the orifice  172  has a diameter of about 0.094″ in the unflexed state of the diaphragm  52 . Furthermore, the first end  180  has a wall thickness of about 0.032″ and the diaphragm  52  has a thickness or height of about 0.100″ in the unflexed state of the diaphragm  52 . The forgoing dimensions are merely illustrative of possible dimensions for the orifice  172  and the diaphragm  52 , and will change depending on the particular application at hand. 
     In addition to the reduced flushometer valve pressure sensitivity and the improved valve performance, the elastomeric orifice is resistant to clogging. The skin, or surface, of the elastomeric material stretches during operation. This action frees debris that would normally clog a non-elastomeric orifice. This debris includes sediment and water deposits such as scale. 
     In an alternative embodiment, the orifice  172  can be provided in the diaphragm  22  in lieu of the bypass  26 . In either case, the diaphragm  22  or diaphragm  52 , the first portion  184  of the diaphragm can be positioned between the first end  180  and the second end  182  as well adjacent the first end  180  or the second end  182 . For example, the diameter of the first end  180  can equal the diameter of the second end  182 , but the diameter A of the first portion  184  is less than the diameters of the first end  180  and the second end  182  and the first portion  184  is positioned between the first end  180  and the second end  182 . FIGS. 6 and 7 show the first portion  184  adjacent the first end  180 . In either case, the first portion  184  thickness is less than the thickness of the diaphragm  52  or  22 , so that the orifice  172  has a diameter which is not constant throughout the entire length of the orifice  172 . 
     Although this invention has been described with reference to preferred embodiments, obvious modifications and alterations of the invention may be made without departing from the spirit and scope of the invention. The scope of the present invention is defined by the appended claims and equivalents thereto.