Abstract:
A switchbox for monitoring the position of a manual quarter-turn valve has a housing mountable to the valve to be monitored/controlled. A handle-driven shaft extends through the housing, with one end of the shaft couplable to the valve stem such that movement of the shaft moves the valve stem. One or more shaft position sensor switches interact with a cam on the shaft to signal shaft position and/or provide control signals. A plate coupled to the shaft articulates within a recess on the surface of the switchbox to limit motion of the valve to an operable range, such as between full ON and full OFF. The switchbox has a pair of lock tabs with lock apertures. A lock aperture in the plate is alignable with the lock tab apertures to receive a pin or padlock for locking the valve in a selected position. A potentiometer can be utilized in place of a switch as a shaft position sensor. The switchbox may be used with an original or new handle and may feature detents to allow a range of valve settings.

Description:
CROSS-REFERENCED TO RELATED APPLICATION 
     This application is a divisional of, and claims the benefit of priority to, U.S. patent application Ser. No. 13/019,097, filed on Feb. 1, 2011, the contents of which are incorporated herein by reference in their entirety for all purposes. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure generally relates to apparatus for monitoring and controlling valves and more particularly to switchboxes with limit switches for controlling and monitoring manually operated, quarter-turn valves. 
     BACKGROUND OF THE INVENTION 
     Valves, such as ball valves and butterfly valves are ubiquitous for controlling fluid flow through piping and conduits in many environments. For example, in the industrial environment, valves control the flow of fluids and gasses through pipelines for material supply, venting, cooling/heating, hydraulic actuation and many other applications. While in the past, control valves were typically operated by hand, automated valve operation is becoming more common since it permits computerized and remote operation/control, e.g., from a control room, eliminating manual operation and its attendant labor and risks. In many instances, it is important to keep a valve opened or closed, within a predetermined range of operation, or at a specific degree of openness. These constrictions on valve position can be monitored and/or implemented by limit switches, which sense on valve position and either send a signal representative of position or enable/disable-open/close a circuit which can be used to control process equipment, e.g., a pump which pumps fluid through a pipeline controlled by the valve on which a limit switch is installed. It is known to utilize limit switches on electrically, pneumatically and hydraulically actuated valves to provide a mechanism for controlling valve position (to keep the valve within a predetermined range of motion), as well as to provide signal data indicative of valve position. While automated valves have become common, manual valves continue to be used, e.g., for backup purposes, such as for valves that may be actuated when the automatic valve or its supporting system (e.g., electrical power) fails or is purposely shut down. Manual valves are used as override valves for maintenance purposes and in emergencies, e.g., to assure that a pipeline is shut off. Further, a manual valve may, at times, be utilized for establishing a static degree of openness, e.g., for establishing a constant, reduced flow rate through a system. While limit switch use on manually-actuated valves is known, there is a need for limit switches and switchboxes having improved features and functionality, e.g., pertaining to retro-fitability and compatibility to existing valve assemblies, lockout capabilities, corrosion resistance and capability to maintain a given valve setting. 
     SUMMARY OF THE INVENTION 
     The present disclosure relates to apparatus to aid in controlling a valve having a body, a passageway through the body and an articulable member mounted to a valve stem and positioned within the passageway, the position of the articulable member determining the degree of openness of the passageway. The apparatus has a housing removably attachable to the valve body, a shaft extending through the housing, with one end of the shaft couplable to the valve stem such that movement of the shaft moves the valve stem. A shaft position sensor interacts with a position sensor actuator coupled to the shaft, with the position sensor actuator capable of inducing the shaft position sensor to acquire a state having an associated electrical property indicative of shaft position. The apparatus has a motion limiter coupled to the shaft for limiting the range of motion of the shaft and rotating conjointly there with. A first lock member is coupled to the shaft and rotates conjointly therewith. A second lock member is coupled to the body, the first and second lock members selectively cooperative to allow the shaft to be locked in a first position. In accordance with an embodiment of the present disclosure, the motion limiter and the first lock member may be monolithic. 
     In accordance with a method of the present disclosure for controlling a manually operated valve having a body, a passageway through the body, an articulable member mounted to a valve stem and positioned within the passageway, the position of the articulable member determining the degree of openness of the passageway and an original handle attachable to the valve stem to facilitate turning the valve stem, the following steps may be conducted. Removing the original handle, then installing a switchbox on the valve, the switchbox having a housing removably attachable to the valve body, a shaft extending through the housing, one end of the shaft couplable to the valve stem such that movement of the shaft moves the valve stem, a shaft position sensor, a position sensor actuator coupled to the shaft, the position sensor actuator capable of interacting with the shaft position sensor to induce the shaft position sensor to acquire a state having an associated electrical property indicative of shaft position, a motion limiter coupled to the shaft for limiting the range of motion of the shaft and rotating conjointly there with, a first lock member coupled to the shaft and rotatable conjointly therewith, a second lock member coupled to the body, the first and second lock members selectively cooperative to allow the shaft to be locked in a first position. Installing one of the original handle or another handle. Selectively monitoring electrical signals from the position sensor representative of a position of the shaft; and selectively locking the valve in a selected position. 
     Additional features, functions and benefits of the disclosed apparatus, systems and methods will be apparent from the description and claims which follow, particularly when read in conjunction with the appended figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To assist those of ordinary skill in the art in making and using the disclosed apparatus, reference is made to the appended figures, wherein: 
         FIG. 1  is perspective view of a switchbox mounted on a valve in accordance with an embodiment of the present invention. 
         FIG. 2  is a top view of the assembly of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of a handle pawl and detent of the assembly of  FIGS. 1 and 2  taken along section line  3 - 3  and looking in the direction of the arrows. 
         FIG. 4  is an enlarged perspective view of the switchbox of  FIGS. 1 and 2  separated from the valve, with the handle removed and seen from the top. 
         FIG. 5  is an enlarged perspective view of the switchbox of  FIG. 4  seen from the bottom. 
         FIG. 6  is front view of the switchbox of  FIG. 4  in elevation. 
         FIG. 7  is right side view of the switchbox of  FIG. 4  in elevation. 
         FIG. 8  is rear view of the switchbox of  FIG. 4  in elevation. 
         FIG. 9  is left side view of the switchbox of  FIG. 4  in elevation. 
         FIG. 10  is top view of the switchbox of  FIG. 4 . 
         FIG. 11  is bottom view of the switchbox of  FIG. 4 . 
         FIG. 12  is a exploded view of the switchbox of  FIG. 4 . 
         FIG. 13  is an enlarged perspective view of the interior of the switchbox of  FIG. 4  with the cover and lock plate removed. 
         FIG. 14  is a cross-sectional view of the switchbox of  FIG. 4  taken along lines  14 - 14  and looking in the direction of the arrows. 
         FIG. 15  is perspective view a switchbox in accordance with an embodiment of the present invention mounted on a ball valve. 
         FIG. 16  is a top perspective view of a switchbox with a valve mounting adapter in accordance with an embodiment of the present invention. 
         FIG. 17  is a bottom perspective view of the device shown in  FIG. 16 . 
         FIG. 18  is a bottom view of the device of  FIG. 16 . 
         FIG. 19  is an exploded view of a switchbox in accordance with an exemplary embodiment of the present invention and having a adapter sleeve on the input shaft. 
         FIG. 20  is a perspective view of the interior of a switchbox in accordance with an exemplary embodiment of the present invention, with the cover removed. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       FIGS. 1 and 2  show a valve switchbox  10  in accordance with an embodiment of the present invention attached to the mounting plate  12  of a butterfly valve  14 . This attachment may be accomplished by a plurality of screws or bolts extending up through the mounting plate  12  into threaded apertures in the switchbox  10 , drawing the switchbox  10  into close mechanical engagement with the mounting plate  12 . Alternatively, the mounting plate  12  could utilize a plurality of threaded studs or the switchbox  10  could have a plurality of apertures therein to allow bolts to secure the switchbox  10  to threaded apertures in the mounting plate  12 . The valve  14  has a body  16  in which a shaft-mounted disc  18  articulates to open and close a throat  20  through which a fluid may pass (when open). In this disclosure, “fluid” would include liquids, gases and flowable solid particulates, etc. A handle  22  on the switchbox  10  is used to control the position of the disc  18  in the valve throat  20 . Typically, a valve, such as valve  14 , would be provided with a handle that would be attached directly to the shaft supporting the disc  18 . As shown in  FIG. 1 , the valve switchbox  10  of the present disclosure can be positioned to intermediate between the handle  22  and the valve  14 . An optional aspect of the present disclosure is that the handle of an existing valve  14  can be utilized with the switchbox  10  in instances when the switchbox  10  is retrofitted to the valve  14 . In this manner, the handle will likely be properly sized for the given application, e.g., long enough to provide sufficient leverage to allow operation, as well as properly marked and colored, e.g., with indicia and colors symbolic of valve function, for identifying the composition of the fluid that is controlled by the valve  14 , as well as open and close directions, warnings, etc. Alternatively, a new handle can be utilized with the switchbox  10 , which has attributes more appropriate for the task it must perform. As shown in  FIGS. 1 ,  2  and  3 , the handle  22  may be provided with a position lock release  24 , e.g., having a trigger lever that releases a positioning tooth  40  from an associated detent  36  to allow the valve  14  to be selectively locked in position and unlocked to allow re-positioning. 
     The switchbox  10  features a lock plate  26  that turns in unison with the handle  22  and is positionable in alignment with lock tabs  28  or  30  such that when the aperture  26   a  of the lock plate  26  is aligned with either aperture  28   a  or  30   a , a pin, padlock, cable or other lock may be inserted there through to hold valve  14  in a specific position. These features may be utilized as safety features, e.g., to retain a valve  14  in the closed position while maintenance is conducted down-line of the valve  14  (to prevent someone from opening the valve inadvertently). Alternatively, the valve may need to be locked open to provide essential supply of material or cooling fluid down-line. The lock plate  26  may also have a configuration that allows it to function as a motion limiter. More particularly, the lock plate  26  shown may be limited to a range of motion between stop surface  34  (valve closed position) and stop surface  32  (valve open position). Alternatively, the switchbox  10  may be configured to allow full rotation of the valve  14  or embody different limits on the range of motion of the valve  14  by varying the position of the stop surfaces  32 ,  34 , the shape and dimensions of the stop plate  26 , or by utilizing moveable stop surfaces  32 ,  34  on adjustable (moveable) stops. As shown in  FIGS. 2 and 3 , detents  36  may be provided on the switchbox  10  to enable the handle  22  (and disc  18 ) to be movably positioned to a selected position (representing an associated degree of openness of the valve  14 ). The detents  36  permit the valve  14  to be positioned at a selected intermediate position between the opened and closed positions and to retain that selected position notwithstanding the force of fluid flow through the valve (until purposely repositioned by an operator). A spring or other resilient member (not shown) may be used to bias the tooth  40  into engagement with a detent  36 . The various positions of the valve, instructions for use and other information may be expressed by indicia  38   a - d  that may be embossed or otherwise placed on the switchbox  10 . 
       FIGS. 4-11  show that the switchbox  10  has a cover  42  and a base  44 , which may be attached by bolts or other fasteners  46  distributed around the periphery of the switchbox  10 . Alternatively, the cover  42  may be glued or fused to the base  44 , which would prevent access to the interior of the switchbox, which may or may not be preferred, depending upon the application, e.g., considering the non-adjustability and reliability of internal components, cost and other factors. A shaft  48  extends through the cover  42  for fitting to a handle or other turning apparatus, such as a motor driven member. The shaft  48  may be provided with a threaded aperture  50  for receiving a bolt or screw to hold the handle  22  on the shaft  48 . Alternatively, the shaft  48  may retain the handle  22  by means of an interference fit, a set screw or other conventional means. The opposing mating surfaces  52 ,  54 , respectively of the cover  42  and the base  44  have a generally complementary castellated shape, which prevents relative shearing motion and allows the fasteners  46  (disposed proximate the corners of the switchbox  10 ) to be recessed below the upper surface  56  of the cover  42  without substantially thinning the cover thickness. Recessing the fasteners below the surface permits the lock plate  26  to pass there over, as well as facilitating handle operation (without hitting knuckles or the handle  22 ) on upstanding fasteners  46  and also resists contaminant infiltration at the fastener openings  42   b ,  44   b  in the cover  42  and base  44 , respectively (see  FIG. 12 ). The upper surface of the cover  42  features a recessed area  58  defining the area through which the lock plate  26  can be articulated and delimited by the stop surfaces  32  and  34 . The lock plate  26  shown is generally triangular in shape, but could be other shapes, depending upon the shape of the recessed area  58 . When rotated to abut stop surface  34  (illustrated to be the closed position for the valve  14 ) the aperture  26   a  aligns with aperture  28   a  (see  FIGS. 4 and 5 ) in lock tab  28 , allowing a lock (not shown) to be slipped through the aligned apertures  26   a ,  28   a , preventing the lock plate  26 , shaft  48 , handle  22  and valve  14  from being turned from the closed position. As shown in phantom view, the lock plate  26  can be rotated counter-clockwise to a position abuting stop surface  32  to the open position and locked there via lock tab  30 . Detents  36  communicate with a relief groove  60  that communicates with the recessed area  58  of the cover  42  and optionally may extend across the recessed area (see  FIG. 12 ). The relief groove  60  permits materials, e.g., fluids, which spill or condense on the cover in the area of the detents  36  to flow out of the detents  36 , onto the recessed area  58  and off the cover  42 . The recessed area  58  may also incorporate a groove or gutter (not shown) to channel fluids off the cover  42 . In this manner, the likelihood of fluid intrusion into switchbox  10  or damage of the switchbox  10  by solvents is reduced and any fluids which could otherwise fill and obstruct the detents  36 , e.g., after drying and hardening, is drained before drying. As shown in  FIG. 4 , the lock plate  26  may incorporate reliefs  26   b  and  26   c  to accommodate portions of the handle  22  in a retrofit application. The lock plate  26  has a shaft aperture  26   d  which mates with the shaft  48  to assure conjoint rotation. As shown more clearly in  FIG. 13 , the shaft  48  has a bead  48   d  accommodated in a mating recess in the shaft aperture  26   d  which assures a specific shaft-to-lock plate assembly orientation. 
       FIG. 5  shows that the bottom surface  62  of the switchbox  10  may have a plurality of mounting apertures,  64 , e.g., for accommodating studs or screws (not shown). In the instance where the switchbox  10  is attached to a valve mounting plate  12  via bolts, the apertures  64  may be threaded. A plurality of apertures  64  may be provided to match a variety of bolt/fastener patterns and permit the switchbox  10  to be mounted to a variety of valves (mounting plates or adapters). An output socket  66  extending from or coupled to the shaft  48  has a central aperture  68  adapted to matingly accommodate a valve shaft in order to transfer rotational motion to the valve shaft. Alternatively, the central aperture  68  can be fitted with an adapter bushing  70  (see  FIG. 14 ) for intermediating between the shape of the central aperture  68  and the shape of a given existing valve shaft. An adapter bushing  74  (see  FIG. 19 ) may also be utilized to adapt a given shaft  48  to a given handle  22 . 
       FIG. 7  shows that the base  44  may be provided with an opening  72  to accommodate electrical wiring and may be adapted to receive and cooperate with electrical conduit to protect electrical wires entering the switchbox  10  and prevent intrusion of contaminants into the switchbox  10 . Alternatively, quick-disconnect electrical connectors, such as Hirschmann connectors, pin connectors or the like may be used to connect external wiring to electrical components, e.g., switches  76 ,  78  (see  FIG. 12 ) inside switchbox  10 . 
       FIG. 11  shows that the fastener  46  may be a bolt that interacts with a nut captured in base  44 . 
       FIG. 12  shows the interior contents of the switchbox  10 , i.e., within the interior hollow  10   a  thereof. The shaft  48  has an upper portion  48   a  adapted to couple to a handle  22  and a lower portion  48   b , the outer exterior surface of which functions as a cam. A bottom portion  48   c  extends through a bore  44   a  in the base  44  to couple to a valve shaft (not shown) directly, or via an adapter  70 . While a one-piece shaft  48  is depicted, the cam shape of the lower portion  48   b  could be executed as a separate element which could be glued, welded, keyed or otherwise retained on shaft  48  so as to turn in unison with the shaft  48 . In the instance of a removable, separate cam element, a variety of cam shapes could be fitted to the shaft  48  in order to accommodate a variety of different switchbox applications. The lower portion  48   b  turns relative to switches  76 ,  78 , which are mounted on corresponding mounting plates  80 ,  82 , respectively, which feature recesses  80   a ,  82   a , respectively for matingly receiving and holding the switches  76 ,  78  in a stable position. The switches  76 ,  78  may be retained in the recesses  80   a ,  82   a  by screws, rivets, glue or any conventional means. The mounting plates  80 ,  82  are retained by screws that thread into the base  44 . Slotted holes  84  in the mounting plates  80 ,  82  permit adjustment along the range limited by the slotted holes  84 , such that the switches can be positioned to actuate at a particular angular position of the cam. During installation, the valve  14  can be placed in a selected position, then the position of the switches  76 ,  78  adjusted. Proper operation can be verified based on switch  76 ,  78  output. Terminal blocks  86 ,  88  are retained in retainers  90  extending from the interior of the base  44  to retain wires (not shown) entering the switchbox  10  through opening  72 . Alternatively, the terminal blocks  86 ,  88  could be retained in the switchbox  10  by screws, rivets, glue or any other conventional means, or the wiring could be connected directly to the switches  76 ,  78  without connecting to terminal blocks  86 ,  88 . Seals  92   a ,  92   b  and  92   c  seal the cover  42  and the base  44  to the shaft  48  and the cover  42  to the base  44 , respectively, preventing intrusion of contaminants into the switchbox  10 . 
       FIGS. 13 and 14  show the switches  76 ,  78  mounted to the mounting plates  80 ,  82 , which are attached to the base  44 . The terminal blocks  86 ,  88  are retained by retainers  90 . (No wires are shown running between the exterior and the terminal blocks  86 ,  88  or between the switches  76 ,  78  and the terminal blocks  86 ,  88  for simplicity of illustration.) The shaft  48  has a lock plate mounting area  48   e  featuring a bead  48   d  that mates with a corresponding relief in the lock plate aperture  26   d  to establish a specific assembly orientation of the lock plate  26  relative to the shaft  48  and the lower portion  48   b  (cam). The switches  76 ,  78  may be used to signal the position of the shaft  48  by the cam shape of lower portion  48   b , i.e., by being turned ON/OFF due to cam action on the switches, moving a switch actuator lever or button. Alternatively, switch operation may be a signal to turn an associated device, e.g., a pump, ON/OFF. For example, a pump which pushes fluid through the valve  14  may be disabled by a switch  76  or  78  when the shaft  48  is turned to a position representing a closed position of the valve  14 , preventing the pump from exercising the fruitless function of attempting to urge a fluid through a closed valve. Using the same example, the OPEN position of the valve  14  may cause a switch  76 ,  78  to enable running of the pump. The switches  76 ,  78  may also be used to inform an operator or computer controller that the valve has achieved a specific position, corresponding to a degree of openness. For example, a closed valve  14  may cause a switch  76 ,  78  to signal to a controller that the valve is in a closed condition, such that the controller (human or automatic) will terminate pump operation. Further, if a signal is given to move the valve to the open condition, a switch  76 ,  78  may inform a controller that the valve  14  has achieved the desired state of openness. The switchbox  10  can accommodate more or fewer switches, each switch potentially performing indicating functions and/or enabling/disabling functions at selected positions of the valve  14 . The switchbox  10  may be used for data collection (pertaining to valve position over time) and for process tracking. 
       FIG. 15  shows the switchbox  10  used in conjunction with a ball valve  94  with a T-handle  96 , which, as shown, does not incorporate a detent engagement apparatus. Alternatively, the T-handle could incorporate a mechanism to engage detents  36 . 
       FIGS. 16-18  show the switchbox  10  coupled to a mounting plate adapter  98  having a primary mounting plate  98   a  which would be coupled to a valve, like valve  14  or  94 , a secondary mounting plate  98   b  which couples to the switchbox  10 , and an intermediate portion  98   c  connecting the primary and secondary mounting plates  98   a  and  98   b . The coupling of the mounting plate adapter  98  to the valve  14 ,  96  may be by screws, nuts and bolts, studs or bolts threadedly received in apertures  64 ,  98   d , clamps or other conventional means. 
       FIG. 19  shows a switchbox  10  which utilizes an adapter bushing  74  on the upper portion of the shaft  48   a  to receive a mating handle, such as handle  22  (see  FIG. 1 ). The adapter bushings  70  (see  FIG. 12) and 74 , mounting plate adapter  98  (see  FIG. 16 ) and the provision of a plurality of mounting aperture  64  patterns, promote the universal use of the switchbox  10  to a variety of valve applications with either the original valve handle or a replacement handle  22 . In the instance that the original handle incorporates lockout features that are incompatible with the switchbox  10 , the switchbox  10  provides any necessary lockout feature, i.e., via the interaction of a lock with the lock plate  26  and lock tabs  28 ,  30  (through alignment of the aperture  26   a , with aperture  28   a  or  30   a  and insertion of the lock through the aligned apertures). It is understood that a manual valve may have lockout features whereas an automated valve may not, in that, a locked-out condition of a manually operated valve will be observable to the operator of the valve and no effort would be expended in futilely attempting to turn the valve. In the instance of an automated valve, the automated valve actuator may not have a means to sense that the valve is locked and the actuator may futilely attempt turning resulting in damage to the valve or the actuator. 
       FIG. 20  shows a switchbox  110  wherein one of the switches is replaced with a potentiometer  111 . The potentiometer  111  can signal a variable resistance based upon rotational displacement, such that a potentiometer gear  113  which is rotated by a shaft-mounted gear  115  can be utilized to ascertain the rotational position/displacement of the shaft  148  (and an associated valve (like valve  14  or  94 ) via electronic interpretation of the potentiometer output, such as by an analog-to-digital converter. In this manner, the position of the shaft and associated valve can be determined at any position and is not restricted to discrete positions associated with cam-induced switch signaling. The potentiometer  111  and potentiometer gear  113  can be retrofitted to a shaft  148  having a configuration like that of shaft  48  shown in  FIG. 12  and can optionally be used in conjunction with one or more cam-driven switches  176 . Because a potentiometer output may be stored or interpreted as zero at any given angular position of turn, there is no need to adjust the angular mounting position of the potentiometer  111  within the switchbox  110 , e.g., by way of an adjustable mounting plate, such as  80 ,  82  (see  FIG. 12 ). A mounting plate,  80 ,  82  of an appropriate thickness could be utilized to establish the alignment of potentiometer gear  113  and shaft-mounted gear  115  by setting the height of the potentiometer  111 . 
     The switchbox  10 ,  110  may be made from metal or plastic and such material may be selected to be corrosion-resistant and compatible with a given piping system, e.g., plastic construction for a plastic piping system. Plastics which may be used include PVC, CPVC and GFPP. Plastic composition is often lighter and may be preferred in applications requiring lighter weight. These comments as to material of composition apply to the cover  42 , base  44 , mounting plates  80 ,  82 , as well as the shaft  48 ,  148 . The shaft  48 ,  148  may also be made from 300 or 400 Series stainless steel or aluminum depending upon the application. 
     The switchbox  10  provides electronic indication/control based upon valve position. These features can be conferred on a mechanically operated valve and the switchbox is retrofittable to a manual valve which originally did not have such indication and control capability. It should be appreciated that a manually-operated valve  14  may be driven by automated apparatus or vice versa, by subsequent connection/disconnection from automated apparatus, such as a motor. For example, an automated valve may have the automatic rotating equipment disconnected and a handle installed either temporarily or permanently, in its place. In either case, the switchbox may be incorporated on the valve intermediate either the manual handle or the automated turning apparatus, either permanently or temporarily.