Abstract:
A flow noise restrictor for use with a valve. The flow noise restrictor reduces the flow area as the valve closes and forms vortices to reduce the noise such as due to the Bernoulli effect.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is related to and claims priority from U.S. Provisional Patent Application No. 61/542,666, filed Oct. 3, 2011 and is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to valves. More specifically, the present invention relates to flushometers or faucet valves having a flow noise restrictor. 
       BACKGROUND OF THE INVENTION 
       [0003]    Numerous valves utilize a valve seat in their structure. Many of these structures have a valve structure that, typically, descends to seat upon the valve seat. Where there is a pressure differential between the area “upstream” of the valve seat and the area “downstream” of the valve seat, the energy of the system may be dissipated in undesirable ways. For example, cavitations and/or vibrations can occur, particularly at the moment the valve closes. These occurrences are often reflected in noise at the valve or its associated fixture or upstream/downstream due to vibrations traveling throughout the system. In liquid systems, the vibrations are sometimes caused by pressure waves traveling in the piping system that supplies the valve including what is commonly called water hammer. At other times the cause of the vibrations is more local due to gas trapped in the liquid providing an unstable dynamic system that tends to vibrate at certain flow conditions. 
         [0004]    One particular type of valve that can exhibit “noise” problems is a flushometer, commonly used with water closets and urinals. Two particular types of flushometers are well known: diaphragm flushometers and piston flushometers. Diaphragm-type flushometers are exemplified by the flush valve shown in U.S. Pat. No. 6,616,119, which is hereby incorporated herein by reference. Piston-type flushometers are also known, as exemplified by the flush valve shown in U.S. Pat. No. 4,261,545, which is hereby incorporated herein by reference. 
         [0005]    A flushometer or faucet valve includes a body  10  with an inlet  12  and outlet  14 , a valve assembly  15  with a valve seat  26 , a valve member  17  movable in the body  10  toward or away from the valve seat  26  to control flow from the inlet  12  to the outlet  14 . The valve assembly  15  has a pressure chamber  50  acting on one side of the valve member  17  opposing the inlet pressure on the other side of the valve member  17 . A bypass  40  connects the chamber  50  with the water inlet side. Pressure in the chamber  50  maintains the piston  80  or diaphragm  18  seated to the valve seat  26  and the valve assembly  15  in the closed position. There is a relief valve  30 , which may be a mechanical relief valve stem  32  or a solenoid  99  ( FIG. 3A ) driven, that vents the chamber  50  to the outlet  14  side of the valve to permit the piston  80  or diaphragm  18  to move away from the valve seat  26  and open and control the water flow thru the valve. The piston  80  or diaphragm  18  may have a portion  89 / 48  to keep it concentric to the valve seat  26  and in axial alignment with the valve seat  26 . The valve typically has a refill head  47  or similar flow control device on the outlet side of the diaphragm  18  or piston  80  to confine the path of flow. Valves of this kind are taught in prior art for example in U.S. Pat. Nos. 5,881,993; 5,887,848; 5,213,305; 5,244,179; 6,182,689; 6,260,576; 5,332,192 5,967,182. 
         [0006]    It is well known, that in certain environmental and flow conditions, flushometers, such as those discussed above, can start to vibrate and cause noticeable and sometimes undesirable noise. Valve noise in the above described type of valves can be generated thru various mechanisms. If the pressure in some areas falls below vapor pressure due to the Bernoulli Effect, cavitation can occur, which can cause violent oscillations and forces on the valve. Air may become trapped or present in the air chamber, such as due to a high level of gas dissolved in the water from the inlet. Air entrapped in the pressure chamber  50  can introduce a different impedance, due to the variance in compression of the mixed air/water fluid compared to only water, of the piston/diaphragm and pressure chamber  50  and therefore make the flow unsteady. In addition, the piping upstream or downstream of the valve can cause undesirable oscillations in the valve. 
         [0007]    This noise can also be described as flutter or water hammer. Numerous attempts have been made to address such noise. Some valves as described in U.S. Pat. No. 4,248,270 employ a resilient flow control device that deflects or deforms under the inlet pressure, and therefore dynamically controls the flow rate. U.S. Pat. No. 6,616,119 employs a diaphragm that has a molded rubber skirt on the inlet side of the flush valve which deforms with pressure and controls the flow. The skirt attempts to dampen vibration with “friction” tabs. The disadvantage of the resilient member often is that the modulus of elasticity of such members rapidly changes with temperature. It therefore makes it difficult to control the flow rates consistently over different operating temperatures due to the tabs&#39; (of the &#39;119 patent) friction against the outer diameter of the barrel. 
         [0008]    Another means to control noise is to introduce friction between the moving diaphragm or piston and the valve housing. For example, U.S. Pat. No. 5,865,420 diaphragm teaches a refill head  47  on the outlet side of the valve which introduces friction between the housing and the moving refill head, therefore damping vibrations. The aforementioned refill head  47  on the inlet side also touches the housing barrel to introduce friction. 
         [0009]    Some valves, e.g. U.S. Pat. No. 4,040,440 employ sound absorbing treatment on the outlet side, or generate turbulence as taught in U.S. Pat. No. 4,967,998. Some flushometer designs have grooves in the outlet skirt as well (made of plastic or metal) to control the flow as well. Other cage type valves employ perforated and grooved members, plugs and skirts as a means to make the flow turbulent to reduce noise throughout the flush cycle as shown in U.S. Pat. Nos. 4,024,891 or 3,990,475. However, the limited stroke of the chamber controlled valves does not allow for elaborate absorption treatment or perforation of members. In addition, the difficulty of those perforated and grooved members shown in prior art, is that even though they suppress noise thru the introduction of turbulence, they severely restrict flow thru the valve when the valve is in an open position or opening/closing stroke. In other configurations, the geometry adds friction or flow resistance to the opening or closing stroke. This cannot be adopted in valves that have a smaller stroke and larger flow rate requirements. 
         [0010]    Further complicating matters, some of the portion of the noise/hammer occurs at the moment before the closing of the valve is completed. The Bernoulli effect is especially strong at that moment, as the inlet pressure builds up to static pressure of a typical residential or commercial water supply line, while at the same time the pressure on the outlet dramatically reduces (typical to atmospheric pressure). Present mechanisms at the outlet side of the valve seat have only little effect at that moment. 
       SUMMARY OF THE INVENTION 
       [0011]    One embodiment of the invention relates to a flow noise restrictor having features for generating vortices. 
         [0012]    One embodiment of the invention relates to a flush valve having a valve body having an inlet and an outlet. A valve assembly is included comprising a valve member and a valve seat. The valve member is seatable upon the valve seat to seal the inlet from the outlet. The valve assembly has a flow noise restrictor adjacent to the valve seat and partially defining a fluid flow path. The flow noise restrictor has a sidewall and a fluid flow edge defining a plurality of features. 
         [0013]    One embodiment of the invention relates to a valve assembly comprising a valve member and a valve seat. The valve member is seatable upon the valve seat to seal the inlet from the outlet. The valve assembly has a flow noise restrictor adjacent to the valve seat and partially defining a fluid flow path. The flow noise restrictor has a sidewall and a fluid flow surface defining a plurality of features. 
         [0014]    One embodiment of the invention relates to a flow noise restrictor for use with a valve assembly. The flow noise restrictor comprises a circular sidewall. The circular sidewall has an upper edge and a lower edge nonparallel with each other. One of the upper edge and lower edge configured to engage a portion of a flush valve. The other of the upper edge and lower edge define a plurality of features. 
         [0015]    Additional features, advantages, and embodiments of the present disclosure may be set forth from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary of the present disclosure and the following detailed description are exemplary and intended to provide further explanation without further limiting the scope of the present disclosure claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The foregoing and other objects, aspects, features, and advantages of the disclosure will become more apparent and better understood by referring to the following description taken in conjunction with the accompanying drawings, in which: 
           [0017]      FIG. 1  is a side, partial sectional, view of a diaphragm flushometer. 
           [0018]      FIG. 2  is a side, partial sectional, view of a piston flushometer. 
           [0019]      FIG. 3A  is a side, cross-sectional view of a diaphragm valve of one embodiment of the invention;  FIG. 3B  is a perspective, cross-sectional view of the diaphragm valve of  FIG. 3A . 
           [0020]      FIGS. 4A-4D  illustrate diaphragm valve assemblies of various embodiments;  FIG. 4A  illustrates a flow noise restrictor having triangular features;  FIG. 4B  illustrates a flow noise restrictor having sinusoidal features;  FIG. 4C  illustrates a flow noise restrictor having irregular, sharp features;  FIG. 4D  illustrates a flow noise restrictor irregular, sharp features and large window openings. 
           [0021]      FIG. 5A  is a side, cross-sectional view of a piston valve of one embodiment of the invention;  FIG. 5B  is a perspective, cross-sectional view of the piston valve of  FIG. 3A . 
           [0022]      FIGS. 6A-6D  illustrate piston valve assemblies of various embodiments;  FIG. 6A  illustrates a flow noise restrictor having piston features;  FIG. 6B  illustrates a flow noise restrictor having sinusoidal features;  FIG. 6C  illustrates a flow noise restrictor having irregular, sharp features;  FIG. 6D  illustrates a flow noise restrictor irregular, sharp features and large window openings. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and made part of this disclosure. 
         [0024]    In some embodiments, the present invention relates to a flow noise restrictor  100  associated with a valve assembly  15  in a flushometer valve  1 . The flow noise restrictor  100  may have features  110  (such as regular triangular features  111 , sinusoidal features  113 , and irregular triangular features  113 ), which create vortices between the valve member  17  and the valve seat  26  as the valve member  17  is being seated. The flow noise restrictor  100  narrows the inflow area as the valve assembly  15  closes. It should be appreciated that the water may flow through an area defined by the valve seat  26  and the flow noise restrictor  100 , with the features  110  of the flow noise restrictor  100  contributing to that area. As the distance between the flow noise restrictor  100  and valve seat  26  decreases during the valve assembly  15  closure, the percentage of the flow area contributed by the features  110  of the flow noise restrictor  100  increases. The features  110  of the flow noise restrictor  100  introduce larger scaled vortices that provide mixing of the fluid without significantly changing flow resistance in the open position or adding friction to the opening and closing stroke. 
         [0025]      FIG. 1  illustrates a typical prior art diaphragm flushometer valve and  FIG. 2  illustrates a typical prior art piston flushometer valve. The flush valve  1  includes a body  10  having an inlet  12  and an outlet  14  and a main valve seat  26  for sealing by a valve assembly  15 . A pressure chamber  50 , or electronic control mechanism (for example, as shown in  FIG. 3A ), is typically provided above the valve assembly  15 . This pressure chamber  50  may be pressurized by the line pressure of the inlet through bypasses  40  which place the pressure chamber  50  in fluid communication with the inlet  12 . The pressure chamber  50  is sealed from the outlet  14  by a relief valve  30  of the valve assembly  15 . The relief valve  30  includes a relief valve stem  32  extending downward through a relief valve seat  38  within the valve assembly  15  such that unseating of the relief valve  30 , such as by tilting the valve stem  32 , allows venting of the pressure chamber  50  to the outlet  14 . This reduces the pressure in the pressure chamber  50 , allowing the valve assembly  15  to be forced off of the main valve seat  26  by the pressure of the inlet  12 . The water from the inlet  12  may then pass through the main valve seat  26  to the outlet  14 . The valve assembly  15  reseats as the pressure chamber  50  reaches equilibrium pressure with the inlet forces acting on the valve assembly  15 . 
         [0026]    With reference to  FIG. 1  (diaphragm flushometer) and  FIG. 2  (piston flushometer), the valve assembly  15  is actuated by an operating handle  22  which is fastened to the valve body  10  by means of a coupling nut  23 . The handle  22  is connected to a plunger  27  which extends to the interior portion of the valve body  10  below the main valve seat  26 . As best shown in  FIG. 2 , the plunger  27  is guided and supported by a bushing  28  and is restored by a spring  25 . A seal packing  33  may be snapped on the end of bushing  28  and prevents leakage outwardly from the handle opening. The valve  1  as shown in  FIGS. 1 and 2  has a manual handle  22  for operation. The valve  1  is equally adaptable to automatic operation, for example by a solenoid  99  as set forth in U.S. Pat. No. 3,778,023, either by mechanized action on the handle  22  or an automatic actuation device directly interacting with the plunger  27  or relief valve stem  32 . 
         [0027]    With respect to  FIG. 1 , the valve assembly  15  of a diaphragm flushometer valve is a diaphragm assembly  16  that includes a diaphragm  18 . In one embodiment, the diaphragm  18  is peripherally held to the body  10  by an inner cover  20 . The diaphragm  18  is seated upon a shoulder  21  at the upper end of body  10  and is clamped in this position by the inner cover  20 . An outer cover  24  is screw threaded onto the body  10  to hold the inner cover  20  in position. 
         [0028]    The diaphragm assembly  16 , as shown in the embodiment of  FIG. 1 , is closed upon a valve seat  26  formed at the upper end of a barrel  31 . The barrel  31  forms the conduit connecting the valve seat with outlet  14 . The diaphragm assembly  16  includes a relief valve  30  having a downwardly extending stem  32  carrying a movable sleeve  34 . Sleeve  34  is positioned for contact by a plunger  27  when operated by a handle  22  as its is conventional in the operation of flush valves  1  of the type described. 
         [0029]    In one embodiment, the diaphragm assembly  16 , in addition to diaphragm  18  and the relief valve  30 , includes a retaining disk  19 , a refill ring  45  and a flow control ring  44 . It should be appreciated that the diaphragm  18  may be a unitary component, such as described in U.S. Pat. No. 7,980,528, incorporated by reference herein. The underside of the retaining disk  19  is threadedly attached to a collar  46 , which in turn is threadedly attached at its exterior to a sleeve  48  which carries the refill ring  45 . The above described assembly of elements firmly holds the diaphragm  18  between the upper face of the refill ring  45  and a lower facing surface of the collar  46 . 
         [0030]    Above the diaphragm assembly  16  is the pressure chamber  50 , which maintains the diaphragm assembly  16  in a closed position when the flush valve  1  is not in use. The pressure chamber  50  is fillable via the bypasses  40  and vents through the relief valve  30  into the barrel  31  and ultimately the outlet  14  of the flush valve  1 . 
         [0031]    As is known in the art, such as  FIG. 1 , when the handle  22  is operated, the plunger  27  will contact sleeve  34 , lifting the relief valve  30  off its seat on the retaining disk  19 . This will permit the  50  discharge of water within the pressure chamber  50  down through the sleeve  84 . Inlet pressure will then cause the diaphragm  18  to move upwardly off its seat  26 , permitting direct communication between the inlet  12  and the outlet  14  through the space between the bottom of the diaphragm assembly  16  and the seat  26 . As soon as this operation has taken place, the pressure chamber  50  will begin to build through the bypass orifice  40  in the diaphragm assembly  16 . As flow continues into the pressure chamber  50 , the diaphragm assembly  16  will move toward its valve seat  26  and stop when it has reached that position, the flush valve  1  will be closed. 
         [0032]    The diaphragm  18  of  FIG. 1  has a peripheral edge  52  which will be held between the shoulder  21  of the body  10  and the inner cover  20 . Spaced from the edge  52  is a downwardly extending rim  35 , shown particularly in the section of  FIG. 1 . When in the closed position, the rim  35  will extend about the upper end of the barrel  31 . In one embodiment, the features  110  are sized on a order of magnitude relative to the distance of the stroke of the valve assembly  15 . 
         [0033]    Generally speaking, for a manual valve, the valve  1  is opened when an relief valve stem  32  is moved and opens a passage to the pressure chamber  50  above the diaphragm  18  or piston  80 , and vents at least a portion the liquid to the outlet  14  side of the valve  2 , therefore lowering the pressure above the diaphragm  18  or piston  80  and allowing the pressure below the diaphragm  18  or piston  80  to move the respective diaphragm  18  or piston  80 , thus opening the valve. For embodiments using an automatic actuation mechanism that triggers the plunger  27 , a similar process occurs. For embodiments utilizing a separate actuation mechanism from the traditional handle  22 , such as utilizing a solenoid, the pressure chamber  50  above the diaphragm  18 /piston  80  is opened by electronic means such as a latching solenoid valve  99 , draining said cavity to the outlet side of the valve  1 , allowing the piston  80 /diaphragm  18  to move to the open position. Various automatic or manual actuation systems are known in the art and may be used without departing from embodiments of the present invention. 
         [0034]    In one embodiment, the flow noise restrictor  100  may be used with a piston flushometer having piston assembly  79 . A piston assembly  79  indicated generally at  34  is adapted to reciprocate within the body  10 . Although one embodiment of a piston assembly  79  is described below, it should be appreciated that the various types of piston assemblies may be used without departing from the present invention. The piston assembly  79  includes a hollow, generally cylindrical piston  80 . The piston  80  has a lower cylindrical portion  89  which is directly adjacent a piston seat area  73 , with the seat area  73  being normally seated upon a seal  83  to close the main valve seat  26  and to thereby control the flow of water through the flushometer valve  1 . 
         [0035]    The piston  80  of  FIG. 2  has a pair of bypass orifices  40 , which are illustrated with an optional filter ring  43 , which ring  43  functions according to known principles for providing additional anti-clogging properties. The interior chamber  42  of the piston  80  has an relief valve seat  38 , which may include a seal  83 . The seat  38  and seal  83  are at the top of a central passage which connects chamber  42  with the outlet  14  side of the flushometer valve  1 . 
         [0036]    The piston assembly  79  also includes a relief valve  30  which normally closes the piston  80 . The relief valve  30  has a shoulder  49  which engages the seal  83 . An operating stem  32  is slidable in the interior chamber  42  of the relief valve  30  and extends to a point adjacent plunger  27 . A spring  85  assists in holding the relief valve  30  in its position to close and seal chamber  42 . 
         [0037]    The piston assembly  79  further includes a cap  86  threadedly engaging the upper wall of piston  80 . The cap  86  has a central stop  87  against which the spring  85  abuts. The stop has holes  88  which provide fluid communication between the piston interior chamber  42  and an upper pressure chamber  50 . A packing member or seal member  64  held between the cap  86  and piston  80  provides a slidable seal separating the pressure chamber  50  from the inlet&#39;s  12  water pressure except through the bypass  43 . 
         [0038]    The piston  80  has a cylindrical wall  70  which is preferably smooth and unobstructed. Directly adjacent the cylindrical wall  70  is a tapered piston area  72  which may have a taper of on the order of about ten degrees, which taper is effective to provide a clear flow path about the piston when it is in the raised position away from the valve seat  26 . Directly adjacent the tapered area  72  is the piston seat area  73  which will close upon the seat  26  when the valve is in the closed position. Directly downstream of the piston seat area  73  is a ring  74  which has an outer diameter slightly less than the diameter of the valve outlet adjacent the seat  26  so that ring area  74  will be inside of the valve seat  26  when the piston  80  is closed. The ring  74  functions as a throttling means in that it substantially reduces flow through the valve outlet just prior to complete valve closure. 
         [0039]    Directly adjacent the throttling ring  74  is cylindrical portion  89  which has a plurality of radially and axially extending ribs  76 . The outer diameter of the ribs  76  is less than wall  70  and just slightly less than the passage through seat  26 . The ribs  76  are thus inside of the major portion of the piston  80  so as not to restrict flow. In a preferred embodiment five ribs  76  are provided for maximizing stability and guidance for the piston  80 , without detrimentally obstructing water flow past the piston  80  when the piston  80  is in the valve open position. At the lower end of each of the axially extending ribs there is a chamfered area  78  which assists in assembling the piston  80  within the flushometer valve  1 . 
         [0040]    The area between each of the circumferentially, generally uniformly spaced ribs  76  is closed by a skirt  90 . As shown, the skirt  90  has a radius slightly less than the exterior surface of the ribs  76 . The function of the skirt  90  is to close the area between ribs to provide control of water flow past the piston  80 , which in turn will provide a more consistent operation of the flushometer. The skirt  90  improves the flow path by maintaining it in an axial direction generally circumferentially about the cylindrical piston portion  89 . By preventing water flow into the sleeve  48 , the skirt  90  also helps prevent any back pressure which might retard closure of the relief valve  30 . 
         [0041]    Typically, during the flush cycle, the water below the valve assembly  15  and passing over the main valve seat  26  exhibits generally laminar flow. The present invention relates to the suppression of noise in valve assemblies. In one embodiment, the present invention suppresses noise at the closing of the valve by causing a maximized pressure drop right before valve closure and also introducing vortices (whirling flow +turbulent flow) into the flow to stabilize the flow across the valve seat  26 . Whirling flow suppresses noise while at the same time not restricting the flow. 
         [0042]    In one embodiment, the invention may be in a form of a flow noise restrictor  100  at the inlet side of the valve. The flow noise restrictor  100  may be a portion of the rim  35 , with a series of regular or irregular features  100 . In some embodiments, the flow noise restrictor  100  is near to the valve seat  26 , such as adjacent the valve seat  26 .  FIGS. 3A-4D  illustrate a diaphragm assembly  16  flushometer valve  1  having a flow noise restrictor  100  of the present invention.  FIGS. 5A to 6D  illustrate a solenoid controlled piston assembly  78  flushometer valve  1  having a flow noise restrictor  100  of the present invention. 
         [0043]    In some embodiments the flow noise restrictor  100  includes a sidewall  101 , a valve assembly surface  102  adjacent a portion of the valve assembly, for example abutting against the diaphragm  18 , and a flow surface  103 , which may be an edge or face of the sidewall  101 . In one embodiment, the flow noise restrictor  100  has a ring-like shape. The flow surface  103  is defined by a plurality of features in the sidewall  101 . In one embodiment, the flow surface  103  is non-parallel with the valve assembly surface  102  and/or the valve member  17 . 
         [0044]    It is not necessary, in one embodiment, for the flow noise restrictor  100  to be in direct contact with the valve seat  26  or the valve body  10 . The flow noise restrictor  100  controls the flow through the valve  1  by restricting the area through which the flow may pass. In one embodiment, more as the piston  80  or diaphragm  18  reaches the valve seat  26  and less as the valve fully opens. In certain embodiments, the flow noise restrictor  100  has proportions relative to the other components of the flushometer valve  1  and particularly relative to the area through which the water flows during a flush cycle that allow for the impact of the induced vortices to become meaningful just prior to the valve  1  closing. It should be appreciated that such allows for unhindered flow when the valve  1  fully opens, but creates an increasing pressure drop before flow reaches the valve seat  26  while closing. This is achieved by giving the flow noise restrictor  100  a variable circumferential cross section, where the cross sectional area (allowing for water flow, such as the area of windows  58 ) increases in the direction of the opposing portion of the valve assembly  15 . 
         [0045]    In one embodiment, the flow noise restrictor  100  comprises a series of features  110 , which may have one or more associated shape (such as triangular  111 , sinusoidal  112 , or irregular triangular  113 ). For embodiments as discussed where the cross sectional area increases, these features  110  have, on average, a decreasing width from a portion of the feature closest the valve assembly surface  102  of the flow noise restrictor  100 . It should be appreciated that individual features  110  may have an inverted shape where the width decreases but the overall total width of all features  110  increases. The features  110  may be such that the flow surface  103  defines a side of the sidewall  101 . 
         [0046]    In one embodiment, at least a portion of the features  110  are holes in the flow noise restrictor  100 . For embodiments where the cross sectional area increases, the area of the holes and/or the number of holes may increase towards the flow surface  103  of the flow noise restrictor  100 . For each particular annular cross-sectional slice or plane, the features define a width. The width of the features may vary in each cross-sectional slice. For example, the width may increase as one proceeds from the valve assembly surface  102  to the flow surface  103 . 
         [0047]    In one embodiment, the flow noise restrictor  100  includes a sidewall  101  that is either curved, curvilinear, or a series of linear edges. The height of the sidewall  101 , i.e. the distance between the flow surface  103  and the valve assembly  15  may vary. In one embodiment, the features  110  are symmetrical. In another embodiment, the features  110  are nonsymmetrical, i.e. irregular. 
         [0048]    In one embodiment illustrated in  FIG. 4A  (diaphragm) and  FIG. 6A  (piston flushometer), this is achieved with triangular shaped features  111  in the sidewall  101  of the flow noise restrictor  100 , which is spaced about the circumference of the valve seat  26 . The triangular pattern around the circumference could be replaced with other geometries such as semi circular or sinusoidal  112  ( FIG. 4B  (diaphragm) and  FIG. 6B  (piston flushometer)), as long as it has a large base area that gets gradually smaller away from flow surface  103 . In addition, the features  110  may be irregular such as  FIG. 4C  (diaphragm) and  FIG. 6C  (piston flushometer), 
         [0049]    In one embodiment, there are at least three features  110  along the circumference of the valve seat. In one embodiment, as many features  110  as feasible are provided to introduce multiple three-dimensional vortical flow structures into the inlet flow to the valve seat  26 , with the hi and low differential in the geometry of the flow noise restrictor  100 . However, the circumferential structures/features need to stay large enough to influence the flow gradually over a larger part of the closing stroke of the diaphragm  18 /piston  80 . In addition, in one embodiment, the features  110  of the flow noise restrictor  100  may be sharp features to add small scale turbulent structures to the inflow of the valve seat  26  geometry. In one embodiment, the features  110  are substantially evenly spaced annularly about the flow noise restrictor  100 . 
         [0050]    In the preferred embodiment the flow noise restrictor  100  on the inlet side of the valve seat  26  is combined with an existing noise reduction design such as methods of friction and flow restriction. This allows for two steps of pressure reduction between the inlet  12  and outlet  14  of the closing valve  1  and therefore minimizes the possibility of cavitation noise. First, the flow noise restrictor  100  provides for a pressure reduction. Second, the refill ring  45  (e.g, for a diaphragm flushometer) provides a reduction in pressure on the outlet  14  side. The use of the flow noise restrictor  100  allows for the suppression of noise (vibration) purely by manipulating the flow. 
         [0051]    In one embodiment, the flow noise restrictor  100  is positioned adjacent either the valve seat  26  or the piston  80 /diaphragm  18 . In an embodiment, the flow noise restrictor  100  is mounted on a moving member of the valve  1 , such as the diaphragm  18  or piston  78 , but an alternate method can be envisioned where the flow noise restrictor  100  can be part of the valve housing or made of two parts, one part being attached to the housing or valve seat and one attached to the diaphragm  18 /piston  80 . In one embodiment, a piston flushometer includes the flow noise restrictor positioned about the periphery of the piston  80 . In one embodiment, at the tapered area  72 . In a further embodiment, the flow noise restrictor  100  includes a portion about the periphery of the piston  80  and a corresponding portion engagable therewith on the valve seat  26 . 
         [0052]    In one embodiment, the downwardly extending rim  35  comprises the flow noise restrictor  100 , with the features  110  being defined by portions of the rim  35  that are removed. 
         [0053]    In one embodiment, the features may include one or more windows  58 . As shown in  FIGS. 4D and 6D , wherein the flow noise restrictor  100  includes a plurality of windows  58  which will modulate the flow of water as the diaphragm  18  (or piston  80 ) closes upon the valve seat  26  at the upper end of the barrel  31 . The windows  58  provide a uniform shape that does not alter the flow area as the valve closes, i.e. the cross-sectional area remains the same during closing. The windows  58  are significant openings in the flow noise restrictor  100  sidewall  101  when compared to the size of the individual features  110 . The window&#39;s  58  geometry size and shape is not small enough to add sufficient vorticity to suppress noise. 
         [0054]    In one embodiment, the features  110  are molded into the flow noise restrictor  100 . In another embodiment, the flow noise restrictor  100  is cut/drilled to form the features  110 . 
         [0055]    In one embodiment, the flow noise restrictor  100  does not contact the barrel  31  or valve seat  26 . 
         [0056]    The foregoing description of illustrative embodiments has been presented for purposes of illustration and of description. It is not intended to be exhaustive or limiting with respect to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosed embodiments. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.