Abstract:
An adjustable device for controlling closure of a valve closure member of a valve includes an adapter for mounting to a valve and an actuator for engaging the valve closure member, which is adapted to rotate about an axis for opening, closing or throttling the valve. The device also includes a slow close assembly that includes at least one friction member, which generates a friction force when the actuator is rotated to thereby limit the speed at which the handle may be rotated.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional application Ser. No. 60/900,888, file Feb. 12, 2007, entitled ADJUSTABLE MECHANICAL DEVICE FOR CONTROLLING VALVE CLOSURE SPEED, which is incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to actuator assemblies for valves and, more particularly, to valve actuator assemblies with slow close mechanisms. 
       BACKGROUND OF THE INVENTION 
       [0003]    The NFPA 1901 standard requires that any valve 3″ or greater in size used on a fire apparatus for water delivery (excludes tank to pump valves, etc) must be equipped with a control mechanism that keeps the valve from being closed in less than 3 seconds. This requirement is specifically targeted to eliminate the possibility of “water hammer,” should a valve be closed too quickly. Water hammer refers to a large volume of flowing water subjected to a rapid stop in flow, which generates a large and destructive shock wave through the piping system that generates a significant spike in water pressure that can cause normal devices to explode. 
         [0004]    Types of slow close mechanisms presently in use include gear operator hand wheels (gear the valve so that the large number of revolutions required effectively limits a persons ability to complete the open/close process too quickly), electric (electronic controls monitor the speed of the open/close process to meet the requirement), and hydraulic devices. 
         [0005]    Electric controls are highly effective, but expensive. Gear operator controls are less expensive, but it is sometimes difficult to make the linkage work well. Hydraulic devices are the least expensive option to meet the NFPA standards and are easily adapted for the large variety of valves operated by push-pull style actuators. 
         [0006]    Some slow close mechanisms rely on fluid flow through a restrictive orifice to control the speed at which a handle shaft of a valve system can be turned. However, such a device does not allow for the handle to be repositioned without removal and repositioning of the device. Another issue with this type of device is that it is subject to breakdown over time, fluid contamination, and variation with fluid temperature which can affect the actual operation of the safety device. Such a device also has a limited travel, i.e. it has internal stops. Consequently, the internal stops of the device must be properly aligned with the mechanical stops of the valve body for proper operation. Also, any air that gets trapped in the slow close device during assembly and/or gets into the device during operation will significantly alter the “slow close” control level of the fluid flowing through the restrictive orifice. It is much easier to protect against the ingress of water or contamination than it is to protect against the ingress of air. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides an adjustable mechanical device for controlling valve closure that can meet or exceed NFPA standards for slow close. Further, the device is adapted to be installed such that it is completely sealed from the elements. The device may be constructed without any internal stops, which eliminates the need to align any internal stops with the valve stops required by conventional closure devices. 
         [0008]    According to one form of the invention, an adjustable device for controlling closure of a valve closure member of a valve includes an adapter for mounting to a valve and an actuator for engaging the valve closure member, which is adapted to rotate about an axis for opening, closing or throttling the valve. The device also includes a slow close assembly that includes at least one friction member, which generates a friction force when the actuator is rotated to thereby limit the speed at which the handle may be rotated. 
         [0009]    In one aspect, the device includes a handle, which is coupled to the actuator. 
         [0010]    In another aspect, the friction member comprises a friction disc. Preferably, the slow close assembly comprises a plurality of friction discs. Further, the slow close assembly may comprise a resilient disc, such as a rubber disc, positioned adjacent the friction disc, wherein the friction generated by the friction disc may be adjusted by the resilient disc. 
         [0011]    According to yet another aspect, the slow close assembly is mounted independent of internal mechanical stops, wherein the slow close mechanism can have a range of motion of without interference with any internal mechanical stops and for example have a range of motion greater than 270° or more. 
         [0012]    According to one form of the invention, a valve includes a valve body with a passageway, a valve closure member in the passageway, which is mounted for movement between a closed position wherein the valve closure member blocks flow though the passageway and an open position wherein the passage is open for fluid flow, and an actuator, which engages the valve closure member. A slow close assembly is provided which includes a housing having a chamber and at least one friction member retained in the chamber. The friction member is coupled to the actuator, with the friction member generating a friction force in the chamber when the actuator is moved to thereby limit the speed at which the actuator may be moved. 
         [0013]    In one aspect, the friction member comprises a friction disc. Optionally, the slow close assembly may include a plurality of friction discs. Further, a resilient disc may be provided and positioned adjacent the friction disc, wherein the friction generated by the friction disc may be adjusted by the resilient disc. For example, the resilient disc may comprise a rubber disc. 
         [0014]    In other aspects, the slow close assembly is configured without internal mechanical stops, wherein the slow close mechanism is adapted to rotate independent of any internal mechanical stops. 
         [0015]    In another aspect, the slow close assembly is a scaled assembly. 
         [0016]    In another form of the invention, a valve includes a valve body with a passageway, a valve closure member in the passageway, and an actuator, which engages the valve closure member, as noted above. The valve further includes a slow close assembly, which includes a housing having a fluidly sealed chamber that is adapted to provide resistance to the movement of the actuator to thereby limit the speed at which the actuator may be moved. 
         [0017]    In one aspect, the chamber is configured without internal stops. 
         [0018]    In other aspects, the slow close assembly includes at least one friction member in the chamber coupled to the actuator, which is adapted to generate friction when the actuator moves to thereby provide resistance to the movement of the actuator. 
         [0019]    In yet another form of the invention, a valve includes a valve body with a passageway, a valve closure member in the passageway, and an actuator engaging the valve closure member, as noted above. The assembly further includes a slow close assembly that includes a housing with a chamber that is adapted to provide resistance to the movement of the actuator to thereby limit the speed at which the actuator may be moved. Further, the slow close assembly is configured without any internal stops. 
         [0020]    In other aspects, the slow close assembly includes at least one friction member in the chamber coupled to the actuator, which is adapted to generate friction when the actuator moves to thereby provide resistance to the movement of the actuator. 
         [0021]    Optionally, a plurality of the friction members are provided in the chamber. Further, a resilient member may be positioned adjacent the friction member, wherein the friction generated by the friction member may be adjusted by the resilient member. 
         [0022]    These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a side elevation view of a valve actuator assembly of the present invention; 
           [0024]      FIG. 2  is a top plan view of the valve actuator assembly of  FIG. 1 ; 
           [0025]      FIG. 2A  is an elevation view of a valve with the valve actuator assembly of  FIG. 1  mounted to the valve; 
           [0026]      FIG. 2B  is a cross-section taken along line IIB-IIB of  FIG. 2A ; 
           [0027]      FIG. 3  is a cross-section view taken along III-III of  FIG. 1 ; 
           [0028]      FIG. 4  is an exploded perspective view of the valve actuator assembly; 
           [0029]      FIG. 5  is an elevation view of another embodiment of the valve of the present invention; 
           [0030]      FIG. 6  is a top plan view of the valve actuator assembly of  FIG. 4 ; 
           [0031]      FIG. 7  is a cross-sectional view taken along VII-VII of  FIG. 5 ; 
           [0032]      FIG. 8  is a side elevation view of a third embodiment of a valve actuator assembly of the present invention; 
           [0033]      FIG. 9  is a top plan view of the valve actuator assembly of  FIG. 8 ; 
           [0034]      FIG. 10  is a left side elevation view of the valve actuator assembly of  FIG. 8 ; and 
           [0035]      FIG. 11  is a cross-section view taken along line XI-XI of  FIG. 8 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0036]    Referring to  FIG. 1 , the numeral  10  generally designates a valve actuator assembly of the present invention. As will be more fully described below, the valve actuator assembly of the present invention incorporates a slow close mechanism ( 15 ), which may be constructed without internal mechanical stops and provides control over the speed of the valve without reliance on a fluid, normally associated with conventional devices. Further, the slow close mechanism allows the control over the speed to be adjusted. 
         [0037]    As best seen in  FIG. 3 , valve actuator assembly  10  comprises a manual actuator assembly and includes an actuator  12 , an adapter  14 , which permits the valve actuator assembly to be mounted to a valve  17  ( FIGS. 2A and 2B ), and a handle  16 . Handle  16  is mounted to the upper end  12   a  of actuator  12  so that when the handle is rotated about axis  10   a , actuator  12  will similarly rotate about axis  10   a  to thereby open, close, or throttle valve  17  to which the actuator assembly is mounted, typically a ball valve. 
         [0038]    Ball valve  17  includes a housing  17   a  and a valve ball  17   b , which is located in passageway  17   c  of housing  17   a  and, further, captured therein by a pair of valve seats  17   d  and  17   e , which form a pair of opposed valve seat sealing surfaces ( FIG. 4 ) for valve  17 . To close the valve, therefore, valve ball  17   b  is pivoted or swiveled about its vertical axis  17   f  on a pivot bolt  17   g  by actuator  12 , which extends into and engages valve ball  17   b . For further details of a suitable valve, reference is made to U.S. application, entitled VALVE WITH ACTUATION SUB-ASSEMBLY, filed Oct. 11, 2005, Ser. No. 11/247,791 (Attorney Docket No. ELK01 P-319), which is hereby incorporated by reference herein in its entirety. As will be more fully described below, the rotation of actuator  12  is limited by slow close mechanism  15 , which relies on friction to limit the speed of rotation of the actuator and, hence, the handle. 
         [0039]    As noted above, handle  16  is mounted to upper end  12   a  of actuator  12  and, further, mounted over a stop plate  18 , which is positioned between handle  16  and a bearing brake  20 , which is mounted over adapter  14  ( FIG. 3 ). Trapped between bearing brake  20  and adapter  14  is a spring  22 , which is captured in a recess  14   a  of adapter  14  and which urges actuator  12  upwardly as viewed in  FIG. 3 , which helps facilitate the assembly of the actuator assembly on the valve. Actuator  12  extends through a bore  14   a  in adapter  14 , which includes a bushing  24 , which provides a low friction surface between adapter  14  and actuator  12 . Located at a lower medial portion of actuator  12  is an enlarged flange  12   b , which bears against a washer  25  positioned between flange  12   b  and the lower facing side of adapter  14 . In this manner, flange  12   b  provides a stop for actuator  12  in the vertical direction (as viewed in  FIG. 3 ). 
         [0040]    Handle  16  includes a collar  16   a , which includes an annular wall  16   c  and a base wall  16   d , which includes a non-circular opening. Upper portion  12   a  of actuator  12  has a non-circular cross-section so that when extended through opening  12   d  of handle  16  rotatably couples handle  16  to the actuator. In this manner, as noted, when handle  16  is rotated about axis  10   a  so too is actuator  12 . 
         [0041]    Collar  16   a  of handle  16  is housed in slow close mechanism  15 , which is mounted over collar  16   a . Slow close mechanism  15  includes a plurality of nested annular members  26 ,  28 , and  30 , which are secured together by sets screws  60  ( FIG. 3 ) (which secure annular member  30  to annular member  28 ) and by a pin  61 , which extends between and secures member  28  to adapter  14 . Annular members  26 ,  28 , and  30  are mounted to the upper end  12   a  of actuator  12  by a coupler  32 , which is secured to upper end  12   a  of actuator  12  by an elongated bolt  34  and washer  36 , and provide an annular space or chamber, which is adapted to provide resistance to the rotation of actuator  12  about axis  10   a , described more fully below. 
         [0042]    Coupler  32  includes a generally cylindrical body but with a non-circular cross-section at its lower end  33 . Lower end  33  inserts into a non-circular opening  26   a  provided in upper wall  26   b  of member  26  to thereby rotatably couple member  26  to coupler  32 . Further, coupler  32  includes an annular flange  38  that extends radially outward. Flange  38  extends into the annular space to the upstanding wall  40  of member  28  but is spaced from lower wall  28   a  of member  28  and upper wall  30   a  of member  30  to thereby form annular spaces  42   a  and  42   b  between flange  38  and the upper wall  30   a  of member  30  and between flange  38  and lower wall  28   a  of member  28 . Positioned in annular spaces  42   a  and  42  are friction discs  44 ,  48 , and  52 . Discs  44 ,  48 , and  52  comprise annular discs and further are optionally formed from a non-sacrificial material for an extended life. As would be understood, the discs provide rotational friction between flange  38  and wall  28   a  of member  28  and between flange  38  and wall  30   a , which provides rotational friction to actuator  12  about axis  10   a . Therefore, discs  44 ,  48 , and  52  provide resistance to the rotation of the actuator about axis  10   a.    
         [0043]    Optionally located between discs  48  and  52  is a washer that provides cushioning, such as a resilient washer, including a rubber disc. Incorporation of a rubber disc positioned between or “sandwiched” between the friction discs provides a wide range of adjustability with respect to controlling the handle and increased adjustment sensitivity. In other words, the rubber washer may be used to increase the resistance to the rotation of the actuator. 
         [0044]    When assembled, therefore, the friction discs form a stack of friction discs that provide drag, which limits the speed at which the valve handle can be actuated and further which can be adjusted. 
         [0045]    As noted above, assembly  10  is adapted to be installed such that it is completely sealed from the elements. Preferably, coupler  32  includes at least two annular grooves  32   a  and  32   b  for receipt and positioning of O-ring seals  56   a  and  56   b  ( FIGS. 3 and 4 ). Member  28  also includes an annular groove  28   b  ( FIG. 4 ) for receipt and positioning of an o-ring seal  56   c . Seals  56   a ,  56   b , and  56   c  therefore, seal the slow close actuation assembly. In this manner, the chamber of the slow close mechanism is sealed. Additional seals (seal  58 ) may be provided about actuator  12  below flange  12   b  at recess  12   c , which is used to seal the actuator in the valve (see  FIG. 2B ). 
         [0046]    As noted above, set screws  60  ( FIG. 3 ) are provided to secure annular member  30  to annular member  28  and further fix the relative compression between the various discs to lock-in the slow close setting of the slow close mechanism. Also, a cap screw  60   a  and seal  60   b  may be provided at wall  30   a  of member  30 , which provides a vent mechanism that can be used during adjustment. For example, the vent may be opened to adjust the actuator and then closed after the adjustment is complete. 
         [0047]    In this manner, actuator assembly  10  and slow close mechanism or device  15  may be formed without internal stops, which eliminates the need for alignment between internal stops and the valve stops, typically required in conventional valve closure devices. Further, the resistance to rotation, and hence the speed at which the closure device can be operated, may be varied as desired by simply changing the material of the rubber washer or eliminating the rubber washer or increasing or decreasing the number of discs, including rubber washers. 
         [0048]    Referring to  FIGS. 5-7 , the numeral  110  generally designates another embodiment of the valve actuator assembly of the present invention. Actuator assembly  110  is of similar construction to actuator assembly  10  but includes a modified handle  116  with a knob  116   a . For further details of the adapter assembly and slow close actuation assembly, reference is made to the previous embodiment. 
         [0049]    Referring to  FIGS. 8-11 , the numeral  210  references another embodiment of the actuator assembly, which comprises a rack and sector actuator assembly and is driven by a rack  217  and a sector gear  216 . Again, actuator assembly  210  is of similar construction to actuator assembly  10  but rather than including a handle  16  includes a sector gear  216  mounted about actuator  212 . Similar to handles  16  and  116 , sector gear  216  extends through an opening provided in member  228  for engagement by a rack  217 . 
         [0050]    Rack  217  and sector gear  216  are supported by a modified adapter  214  on a bracket  219 . Adapter  214  provides a step or shoulder  214   a  to accommodate bracket  219 , which is mounted about adapter  214 . For further details of the actuator assembly (and its slow close assembly), reference is made to actuator assembly  10 . 
         [0051]    Changes and modifications to the specifically described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law including the doctrine of equivalents.