Abstract:
A flow control valve having a valve member engageable with a valve seat. The valve opens when the valve member disengages the valve seat as fluid pressure is bled from a pressure chamber on one side of the valve member. The valve closes after the pressure bleed ends when fluid pressure is metered back into the pressure chamber through a metering path. The speed at which the valve member closes is selectable depending upon the degree to which the metering path is tortuous. Two different tortuous configurations of the metering path are provided by two differently shaped labyrinths. The user can select one closing speed or the other by choosing which labyrinth is in the metering path.

Description:
TECHNICAL FIELD  
         [0001]    This invention relates to a flow control valve for controlling the passage of fluids such as water in an irrigation system. More particularly, this invention relates to a fluid flow control valve that is able to close at different speeds with the user having the ability to select a desired closing speed from among the different speeds.  
         BACKGROUND OF THE INVENTION  
         [0002]    Flow control valves are well known in irrigation systems. Such valves control the flow or passage of water through an upstream pipe and thereby turn sprinklers fed by the pipe on and off. Such valves are often remotely controlled by control signals sent from an automated irrigation controller. For example, the controller often sends an electric actuating signal to a solenoid that is part of the valve to open the valve.  
           [0003]    Certain known flow control valves have up-stream fluid pressure on both sides of the valve member when the valve is closed. When the solenoid is actuated, the fluid pressure in a pressure chamber on one side of the valve member is exhausted or relieved. The upstream fluid pressure is then free to act on the other side of the valve member to disengage the valve member from the valve seat to open the valve. When the solenoid closes, upstream fluid pressure is then metered back into the pressure chamber through a metering path to restore the pressure balance across the valve member. This causes the valve member to reengage against the valve seat to close the valve. U.S. Pat. No. 6,263,901 to Lohde et al., which is assigned to the assignee of this invention, discloses a valve of this type.  
           [0004]    In known flow control valves, the rate of flow into the pressure chamber through the metering path is what determines how quickly the valve closes. It is known in the art that the metering path can be sized to provide a particular closure rate. However, once this is done, the valve thereafter closes at that rate, subject to the caveat that the pressure differential across the valve member affects the closing rate as well. However, for a given design pressure differential across the valve member, a particularly sized metering path will provide a single valve closing speed.  
           [0005]    Certain irrigation applications would ideally utilize flow control valves having different closing speeds. For example, in commercial turf applications, the flow control valve is typically open for an irrigation cycle lasting from 30 to 60 minutes. A standard valve used in such an application might take 20 seconds or so to close after the solenoid reseats. However, 20 seconds is only a small part of the irrigation cycle time, i.e. only about 0.5 to 1.0% of the total cycle time, so that such a valve closing speed is acceptable.  
           [0006]    On the other hand, in other irrigation applications, such as greenhouse, nursery or small scale agricultural applications, a typical irrigation cycle might be much shorter. Sometimes a desired irrigation cycle might last only 30 to 60 seconds instead of 30 to 60 minutes. A valve closure time of 20 seconds then becomes an unacceptably large portion of the entire irrigation cycle. It would be desirable to have a valve that would close much more quickly than a standard valve for use in these applications.  
           [0007]    Separate valves could be manufactured and provided having different closing rates. However, this requires different valve models and requires the retailer and installer of the valves to have the separate models on hand for use in all prospective applications. It also requires the installer to install the correct valve required for each application. There is a need in the art for a flow control valve having a plurality of closing rates with one rate being selectively chosen by the user in one application and another rate being chosen by the user in another application. However, prior to this invention, such a flow control valve was neither known nor available in the art.  
         SUMMARY OF THE INVENTION  
         [0008]    one aspect of this invention relates to a fluid flow control valve. The valve comprises a valve housing having an inlet, an outlet, and a flow passageway between the inlet and outlet. A valve seat is located in the flow passageway. A valve member closes the valve by moving into engagement with the valve seat for blocking flow between the inlet and the outlet and opens the valve by moving out of engagement with the valve seat for permitting flow between the inlet and the outlet. A pressure chamber is provided in the valve housing. One side of the valve member is exposed to inlet fluid pressure tending to move the valve member away from the valve seat and the other side of the valve member is exposed to fluid pressure in the pressure chamber tending to move the valve member towards the valve seat. A metering path is provided to permit water to pass into the pressure chamber from upstream of the valve seat to close the valve. At least two water flow labyrinths are also provided with the labyrinths being differently configured relative to one another such that water flows through the labyrinths at different rates. One or the other of the labyrinths is selectively installed in the metering path to select a desired closing speed for the valve depending upon which labyrinth is in the metering path.  
           [0009]    Another aspect of this invention relates to a flow control valve, which comprises a valve member engageable with a valve seat. The valve opens when the valve member disengages the valve seat as fluid pressure is bled from a pressure chamber on one side of the valve member. The valve closes after the fluid pressure bleed ends when fluid pressure is metered back into the pressure chamber through a metering path. The metering path is tortuous. At least two tortuous configurations of the metering path are provided for the metering path with one or the other of the tortuous configurations being selectively used at any one time to provide at least two different closing speeds for the valve member.  
           [0010]    Yet another aspect of this invention relates to a flow control valve which comprises a valve housing having a valve seat, the valve housing comprising a valve bonnet secured to a valve body. A valve member engages and disengages the valve seat to close and open the valve, respectively. A pressure chamber is provided on one side of the valve member. A metering assembly is mounted in the valve housing for metering fluid pressure to the pressure chamber to close the valve. The metering assembly includes a plug which is selectively insertable into or removable from a bore in the valve housing without disassembling the valve bonnet from the valve body. The plug has a flow passageway therethrough. A labyrinth is carried on the plug in fluid communication with the flow passageway in the plug, the labyrinth defining a tortuous water flow path with the valve member having a closing speed that is dependent upon the degree the flow path in the labyrinth is tortuous. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    This invention will be described hereafter in the Detailed Description, taken in conjunction with the following drawings, in which like reference numerals refer to like elements or parts throughout.  
         [0012]    [0012]FIG. 1 is a is a longitudinal cross-sectional view of an irrigation valve according to this invention;  
         [0013]    [0013]FIG. 2 is a cross-sectional view of a portion of the irrigation valve of FIG. 1, particularly illustrating the metering assembly that determines how quickly the valve closes;  
         [0014]    [0014]FIG. 3 is an exploded cross-sectional view of the metering assembly shown in FIG. 2;  
         [0015]    [0015]FIG. 4 is a top plan view of a portion of the metering assembly shown in FIGS. 2 and 3, particularly illustrating a first labyrinth on one side of a metering disc for providing a first valve closing speed;  
         [0016]    [0016]FIG. 5 is a top plan view similar to FIG. 4 of the metering disc shown in FIG. 4, particularly illustrating a second labyrinth on the side of the metering disc that is opposite to the side shown in FIG. 4 for providing a second valve closing speed; and  
         [0017]    [0017]FIG. 6 is a cross-sectional view through the metering disc shown in FIG. 4. 
     
    
     DETAILED DESCRIPTION  
       [0018]    A fluid flow control valve  2  according to this invention comprises a valve housing  4  that can be installed in the piping of an irrigation system or the like. Valve housing  4  includes an inlet  6  that receives an inlet pipe (not shown) with the inlet pipe carrying water under pressure. Valve housing  4  includes an outlet  8  that similarly receives an outlet pipe (not shown). When valve  2  is open, a flow passageway  10  in valve housing  4  is opened allowing water to flow from inlet  6 , through flow passageway  10 , and then out through outlet  8 .  
         [0019]    An annular valve seat  12  is located inside valve housing  4  in flow passageway  10 . A valve member  14  that is formed at least partially from a resilient diaphragm  16  is movable towards and away from valve seat  12 . Valve  2  is closed when valve member  14  is urged against valve seat  12  as depicted in FIG. 1. Valve  2  is open when valve member  14  is lifted off valve seat  12 .  
         [0020]    Water under pressure at inlet  6  constantly acts on the underside of valve member  14  inside valve seat  12  urging valve member  14  up off valve seat  12 . However, this force is counteracted by the same water pressure in a pressure chamber  18  formed in valve housing  4  above valve member  14 . This balancing water pressure is able to act on a larger area of valve member  14  in pressure chamber  18  than the area acted on by the inlet water pressure, i.e. the area on the underside of valve member  14  located within valve seat  12 , to develop a pressure differential that biases valve member  14  into engagement with valve seat  12 . If desired, a spring  20  can be used within pressure chamber  18  further urging valve member  14  into engagement with valve seat  12 . Thus, in the closed position of valve  2 , the inlet water pressure urging valve member  14  upwardly is opposed and overcome by inlet water pressure within pressure chamber  18  and by the force of spring  20 , both of which jointly urge valve member  14  down into engagement with valve seat  12 .  
         [0021]    Valve  2  is opened by bleeding off at least a portion of the water pressure in pressure chamber  18  at a faster rate than water is being metered into pressure chamber  18 . A solenoid  26  is coupled to a socket  30  in the top of valve housing  4 . When an electrical actuating signal is sent to solenoid  26  from an automated controller (not shown), the plunger of solenoid  26  is lifted to allow a bleed passage  36  extending into pressure chamber  18  to be opened to bleed the water inside pressure chamber  18  to downstream through outlet  8 . Since this bleed is much more rapid than the rate at which water enters pressure chamber  18 , the pressure in pressure chamber  18  is lowered to a point at which the pressure in pressure chamber  18  and the force of spring  20  is lower than the force of the inlet water pressure acting on the underside of valve member  14 . This allows valve member  14  to lift up off valve seat  12  to open valve  2 .  
         [0022]    A metering assembly  40  meters water into pressure chamber  18 . Metering assembly  40  comprises a generally cylindrical plug  42 , a metering disc  44 , and a filter screen  46 . Metering assembly  40  can be installed in valve housing  4  to one side of valve member  14 . When so installed, water upstream of valve member  14  can enter metering assembly  40  through a port  41  in flow passageway  10 , can pass through filter screen  46 , can then pass through metering assembly  40 , and then can exit metering assembly  40  and pass through a metering port  48  in valve housing  14  which port  48  leads to pressure chamber  18 . Port  41 , metering assembly  40  and the various flow passages therein, and metering port  48  all define a metering path between pressure chamber  18  and upstream fluid pressure in flow passageway  10 .  
         [0023]    As will be described in more detail hereafter, metering assembly  40  has at least two different configurations to be able to select two different rates at which water can pass through metering assembly  40 . This gives the user the ability to select from at least two selectively usable and different valve closing speeds. The selection is done according to how metering assembly  40  is configured prior to metering assembly  40  being installed in valve housing  4 .  
         [0024]    Plug  42  has a threaded upper end  50  to allow plug  42  to be threaded into a vertical bore  52  in valve housing  4 . Plug  42  includes a plurality of O-ring seals  54  along the outer diameter of plug  42  to prevent leaks between plug  42  and bore  52 . Plug  42  includes a T-shaped flow passageway  56  that communicates with metering port  48  when plug  42  is installed in valve housing  4 . The lower end of flow passageway  56  is in communication with a cavity  58  on a lower end  60  of plug  42 .  
         [0025]    Metering disc  44  is shaped to be received in cavity  58  in lower end  60  of plug  42 . In order for water to pass through flow passageway  56  in plug  42 , the water must first pass through metering disc  44 . Metering disc  44  is reversible within cavity  58  to change which side of metering disc  44  is uppermost in cavity  58 . This reversal operation is graphically indicated by the arrows in FIG. 3. This is done to selectively vary the length of time that water takes to pass through metering disc  44  to select a particular valve closing speed.  
         [0026]    Referring now to FIGS. 4 and 5, each side of metering disc  44  is provided with a flow labyrinth  1  similar to the types of labyrinths found on drip emitters in the irrigation industry. A first flow labyrinth l 1  is shown on one side of metering disc  44  in FIG. 4. A second different flow labyrinth l 2  is shown on the opposite side of metering disc  44  in FIG. 5. Each flow labyrinth l is fed by an inlet port  62  that passes through the central web  64  of metering disc  44 . Inlet port  62  is offset to one side of metering disc  44 .  
         [0027]    Assuming now that the side of metering disc  44  shown in FIG. 4 is placed uppermost in cavity  58  of plug  42 , water will pass up through inlet port  62  in metering disc  44  to enter labyrinth l 1  from inlet port  62 . In order to pass up into and through flow passageway  56  in plug  42 , the water must pass through labyrinth l 1  into a central chamber  66  of labyrinth l 1 . It is central chamber  66  of labyrinth l 1  that communicates with flow passageway  56 . The only way for water to pass from inlet port  62  to central chamber  66  of labyrinth l 1  is for the water to flow in a back and forth, serpentine fashion pass the various oppositely directed walls  68  that define labyrinth l 1 . Only after moving past all the walls  68  of labyrinth l 1  to reach central chamber  66  can the water then leave metering disc  44  and pass on up through flow passageway  56  in plug  42 .  
         [0028]    As is apparent from FIG. 4, labyrinth l 1  formed on the side of metering disc  44  shown in FIG. 4 has relatively few walls  68  and thus is relatively open. Thus, water will pass relatively quickly through this labyrinth l 1  to be metered into pressure chamber  18  relatively quickly. This causes the valve closing speed to be relatively fast. Thus, when the user is using the valve in an application that requires a fast closing time for the valve, such as an irrigation application having very short irrigation cycles, the user would install metering disc  44  with the side shown in FIG. 4 uppermost in cavity  58  in lower end  60  of plug  42 . A graphical symbol or mark, such as the “hare” or “rabbit” shape  70  shown in FIG. 4, can be molded onto that side of metering disc  44  to help guide the user in the installation of metering disc  44 .  
         [0029]    Referring now to the other side of metering disc  44  as shown in FIG. 5, a differently shaped labyrinth l 2  is carried on the other side of metering disc  44 . This labyrinth l 2  uses more oppositely directed walls  68  and thus is more closed or serpentine than labyrinth l 1  shown in FIG. 4. Thus, water will take longer to pass through labyrinth l 2  shown in FIG. 5 than through labyrinth l 1  shown in FIG. 4. Consequently, labyrinth l 2  as shown in FIG. 5 meters water into pressure chamber  18  at a slower rate thus providing a different and slower valve closing speed. To select this slower valve closing speed, metering disc  44  need be installed in cavity  58  in lower end  60  of plug  42  with the side of metering disc  44  shown in FIG. 5 being uppermost. Again, this side is also provided with a graphical symbol, in this case a “tortoise” shape  72 , to indicate to the user the relative closing speed provided by labyrinth l 2  formed on this side of metering disc  44 .  
         [0030]    Metering disc  44  is held in place in cavity  58  in lower end  60  of plug  42  by filter screen  46  which has a snap fit to lower end  60  of plug  42 . The snap fit is formed by an annular, inwardly protruding ring  74  on the upper end of filter screen  46 . Ring  74  snaps into an annular groove  76  on lower end  60  of plug  42 . Thus, to reverse metering disc  44  within cavity  58 , the user must first pull filter screen  46  off lower end  60  of plug  42 . Then, the user will remove and reverse plug  42  within cavity  58  to change which side of metering disc  44  is uppermost in cavity  58 , i.e. the side that had been uppermost will now be lowermost and vise versa. After metering disc  44  is so reversed within cavity  58 , filter screen  46  can then be snapped back onto lower end  60  of plug  42  to retain metering disc  44  with plug  42 . This metering disc reversal and the associated manipulation of filter screen  46  is done with plug  42  removed from valve housing  4  prior to plug  42  being screwed into bore  52 .  
         [0031]    Valve  2  of this invention provides the user with at least two different closing speeds for use in different irrigation applications. In an application requiring a slow closing speed or in an application in which the closing speed is not critical, the user can configure metering assembly  40  so that metering disc  44  has the side with “tortoise”  72  installed uppermost in cavity  58  in plug  42 . When this is done, the more tortuous labyrinth l 2  on metering disc  44  is in place to slow down the rate at which water will be metered into pressure chamber  18 . In an application requiring a faster closing valve speed, the user simply configures metering assembly  40  with metering disc  44  in a reversed position in plug  42 , i.e. with the side having “hare”  70  being located uppermost in cavity  58 .  
         [0032]    In some instances, one could conceivably not wish the user to be able to select two different valve closing speeds. For example, one might wish to sell a valve only for use in a particular application that requires a single valve closing speed. In this situation, one could still use the same basic design approach as disclosed herein for valve  2 , but metering disc  44  would have the same labyrinth l, either l 1  or l 2 , formed on each side thereof. It would then not matter which side of metering disc  44  was uppermost in cavity  58  as the valve closing speed would be the same in either case. However, for a valve  2  for use in different applications that desirably use different valve closing speeds, metering disc  44  would have differently shaped labyrinths l 1  and l 2  on the opposed sides thereof as disclosed above.  
         [0033]    Various modifications of this invention will be apparent to those skilled in the art. For example, mounting reversible metering disc  44  in valve housing  4  as part of plug  42  allows metering disc  44  to be reversed without disassembling the entire valve housing  4 , namely without removing valve bonnet  80  from valve body  82  which are normally screwed or bolted together. However, if so desired, one could mount reversible metering disc  44  elsewhere in a location that would require disassembly of valve housing  4  for access to metering disc  44 . For example, metering disc  44  could be mounted directly on valve member  14  such that water is metered into pressure chamber  18  through valve member  14  and not through valve housing  4 .  
         [0034]    In addition, filter screen  46  is desirably used on lower end  60  of plug  42  to hold or retain metering disc  44  in place since filter screen  46  can itself be easily removed for cleaning and/or replacement by removing plug  42  from valve housing  4  and by pulling filter screen  46  off the lower end  60  of plug  42 . However, this location of filter screen  46  is not necessary. Filter screen  46  could be separated from plug  42  and metering disc  44  could be retained on plug  42  in some other fashion. Accordingly, the invention is to be limited only by the appended claims.