Abstract:
The sluice gate valve includes at least one binding reduction mechanism to reduce binding during actuation of the sluice gate. In one embodiment the mechanism includes a the guide elements and the tracks, the guide elements and the tracks being arranged such that a predetermined amount of rotational motion of the gate around the stem is permitted during actuation of the valve to reduce valve binding. In another embodiment the mechanism includes a stuffing box assembly including a stuffing box, a bushing, and a collar, where a convex curved surface of the collar slides on a concave curved surface of the bushing such that a predetermined amount of pivoting of the stem up to a predetermined cone angle is allowed. In a preferred embodiment the sluice gate valve includes both mechanisms.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention pertains to the field of valves. More particularly, the invention pertains to a sluice gate valve with a pivotable actuation assembly. 
         [0003]    2. Description of Related Art 
         [0004]    Sluice gate valves, also known as slide gate valves, are known in the art. The sluice gate is typically a wooden or metal plate, which may be circular or rectangular and which slides in grooves of channels in the side of the valve body to actuate the valve. Sluice gates are commonly used in rivers or canals to control water levels and flow rates, in mining operations to recover minerals, and in wastewater treatment plants. 
         [0005]    A gate valve includes an open frame and a slide. Modern sluice gates are commonly made of cast iron or stainless steel. The valve seat may be non-metallic and may have a self-adjusting design. Seats or seals of ultra high molecular weight (UHMW) polyethylene are often used to allow ease of movement and eliminate friction during actuation of the valve. Sluice gate valves may be of the rising stem or the non-rising stem type. In a rising stem sluice, the threaded stem, also known as a spindle, moves upward and downward with the sluice gate during operation. In a non-rising stem sluice, the threaded stem maintains its vertical position as the gate moves upward and downward with respect to the stem and the valve body. 
         [0006]    A prior art sluice gate valve is shown schematically in  FIG. 1  and  FIG. 2 . The sluice gate valve  10  includes a cap  12  and a body  14 . In a closed state, the sluice gate  16  sits in the valve seat  18  to block the orifice  20  of the sluice gate valve  10 . Turning of the stem  22 , which is threaded, actuates the sluice gate to open and close the valve. The stem  22  passes through a thrust nut  24 , which is complementarily threaded for a non-rising stem sluice gate valve. Alternatively, in a rising stem sluice gate valve, the cap  12  or neck  26  is threaded. The sluice gate  16  is guided upward and downward with respect to the valve body  14  by a left wedge  28  traveling in a left track of a left guide  30  and a right wedge  32  traveling in a right track of a right guide  34 . A mounting section  36  is mounted to the end of a pipe or other conduit to align the orifice  20  with the conduit to be controlled by the sluice gate valve  10 . 
         [0007]    Since the sluice gate actuates in a direction substantially parallel to the valve seat, binding of the sluice gate is a common problem in sluice gate valves. Modifications to reduce or eliminate the occurrences of binding are known in the art. 
         [0008]    In U.S. Pat. No. 4,288,059, entitled SLUICE GATE, Gurbin discloses a sluice gate, where the apparatus controlling fluid flow through the gate opening includes a frame and a guide system adapted to retain a gate disc in a slidable relation with the opening. A drawing system laterally displacing the disc relative to the opening is pivotably connected to a lever having long and short ends. A fulcrum between the ends is pivotably connected to the disc. The short end is disposed to bear against a fixed portion of the guide system when the disc is closed, and the long end is connected to the drawing system to obtain a mechanical advantage in drawing pressure when displacing the disc to a partially open position. The lever may be a single lever or a pair of levers to apply a uniform drawing pressure on the disc via a hydraulic cylinder. 
         [0009]    In U.S. Pat. No. 5,415,375, entitled CLOSING SYSTEM FOR CONTROLLING A FLOW WITH PRECISION, Gaboriault discloses a closing system with a closure member and a carriage for translational displacement of the closing member along rails. A jack is mounted on the carriage for non-resilient axial displacements of the closure member to and from a flow opening. The closure member closes the flow opening by first axially aligning the closure member with respect to the flow opening by displacing the carriage. The jack includes pivoting U-shaped arms and axially displaces the closure member to urge the closure member against the flow opening to close it without translational displacement. The closure member is retracted away a minimal distance from the opening for clearance, and then the carriage is actuated to reduce or enlarge the flow opening with precision and without friction to a seal disposed about the opening. 
         [0010]    In U.S. Pat. No. 6,287,051, entitled FIXABLE SEAL SLUICE GATE, Wood et al. disclose a sluice gate with a valve vise having pivot gearing that forces the sluice gate valve uniformly and tightly into sealing contact with a domed seal ring. A plate locator on the valve vise sets the sluice gate plate in a predetermined sealing position for a selected structure of the fixable-seal sluice gate. A dome flange on one or both sides of a base of the domed seal ring is removably bracketed to the sluice gate wall or the sluice gate plate for attachment and detachment of the domed seal ring. In one embodiment, a plate locator is pivotal to the aperture axis with a locator beam that is pivotal on a pivot axis that is orthogonal to the axis of the sluice gate aperture. The sluice gate plate is pivotal limitedly on a ball-and-socket joint on the locator beam for allowing coplanar positioning of the sluice gate plate and the domed seal ring. 
       SUMMARY OF THE INVENTION 
       [0011]    The sluice gate valve includes at least one binding reduction mechanism to reduce binding during actuation of the sluice gate. In one embodiment the mechanism includes a the guide elements and the tracks, the guide elements and the tracks being arranged such that a predetermined amount of rotational motion of the gate around the stem is permitted during actuation of the valve to reduce valve binding. In another embodiment the mechanism includes a stuffing box assembly including a stuffing box, a bushing, and a collar, where a convex curved surface of the collar slides on a concave curved surface of the bushing such that a predetermined amount of pivoting of the stem up to a predetermined cone angle is allowed. In a preferred embodiment the sluice gate valve includes both mechanisms. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  shows a front view of a prior art sluice gate valve. 
           [0013]      FIG. 2  shows a side view of the sluice gate valve of  FIG. 1 . 
           [0014]      FIG. 3  shows an elevated side view of a sluice gate valve in a first embodiment of the present invention. 
           [0015]      FIG. 4  shows an exploded view of the valve of  FIG. 3 . 
           [0016]      FIG. 5  shows an elevated side view of a sluice gate valve in a second embodiment of the present invention. 
           [0017]      FIG. 6  shows an elevated side view of a sluice gate valve in a third embodiment of the present invention. 
           [0018]      FIG. 7  shows a rear view of the valve of  FIG. 6 . 
           [0019]      FIG. 8  shows an elevated bottom view of the valve of  FIG. 6 . 
           [0020]      FIG. 9  shows an elevated top view of the valve of  FIG. 6 . 
           [0021]      FIG. 10  shows an exploded view of the valve of  FIG. 6 . 
           [0022]      FIG. 11  shows an exploded detailed view of a stuffing box assembly of the present invention. 
           [0023]      FIG. 12  shows a schematic view of a track with two guide elements in an embodiment of the present invention. 
           [0024]      FIG. 13  shows a schematic view of two guide elements in separate tracks in an embodiment of the present invention 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    The following terms as used herein are defined relative to the orientation of a sluice gate valve. With reference to the prior art valve shown in  FIG. 1 , the front of the valve is defined as the shown part of the valve in  FIG. 1 , and the rear is the part opposite the front. The top or upper part of the valve is the part of the valve toward the top of  FIG. 1 , and the bottom or lower part of the valve is the part of the valve toward the bottom of  FIG. 1 . The sides of the valve are facing to the left and the right in  FIG. 1 . In descriptions of the movement of the sluice gate during actuation, frontward is in a direction toward the front of the valve, rearward is in a direction toward the rear, upward is in a direction toward the top, downward is in a direction toward the bottom, and sideward is in a direction toward the left or right side. 
         [0026]    The term “non-actuating motion of the sluice gate” as used herein refers to any motion of the sluice gate that does not result in a net movement of the sluice gate along the tracks including, but not limited to, rotation of the sluice gate around the stem, top-to-bottom tilting of the sluice gate away from the angling of the tracks, in-plane rotation of the sluice gate due to a pivoting of the stem around a pivot point in the stuffing box, and any combination of theses movements. 
         [0027]    Prior art sluice valve gates of the type upon which the present invention improves typically hold around 30 feet of head pressure or about 15 psi of pressure. Sluice gate valves of the present invention have been observed to hold greater than 85 psi of pressure and in some cases up to 200 psi of pressure, which is a significant improvement upon the prior art. 
         [0028]    Structural components of a sluice gate valve of the present invention are preferably made of iron with a powder plastic coating or stainless steel with no coating. 
         [0029]    The valve body of a sluice gate valve of the present invention is preferably cast as a single piece with the grooves for the guide elements being machined after the valve body is cast. 
         [0030]      FIG. 3  and  FIG. 4  show a sluice gate valve in a first embodiment of the present invention. The sluice gate valve  110  includes a stuffing box  112 , a valve body  114 , and a sluice gate  116 . In a closed state, the sluice gate  116  sits in the valve seat  118  to block the orifice  120  of the sluice gate valve  110 . A mounting section  136  is mounted to the end of a pipe or other conduit to maintain the orifice  120  in a predetermined alignment with the conduit to be controlled by the sluice gate valve  110 . The valve  110  is preferably mounted using a plurality of bolts or screws. Turning of the stem  122 , which is threaded, actuates the sluice gate to open and close the valve. The sluice gate valve preferably includes a knob  138 , mounted on the end of the stem  122 , which is turned to actuate the valve. In the assembled state, the stem  122  passes through the stuffing box  112  and the neck  126  of the valve body. The stuffing box  112  is preferably mounted to the neck  126  by screws or bolts (not shown) through holes  140  in the stuffing box and holes  142  in the neck. Although three screw holes for three screws or bolts are shown and preferred, any number of screws or bolts may be used to mount the stuffing box to the neck within the spirit of the present invention. The stem  122  is coupled to the sluice gate  116  through a pair of holes  144 ,  146 . 
         [0031]    A thrust nut  124  with a through-hole is mounted between the two holes  144 ,  146  on the gate  116  and maintains the stem  122  on the gate  116 . In a rising stem sluice gate valve embodiment, the thrust nut  124  and gate  116  maintain their vertical positions with respect to the stem  122 , and the stem  122  is threaded with respect to the stuffing box  112  or neck  126  such that the stem  122  rides up or down the with respect to the neck  126  as the stem  122  is turned, thereby vertically adjusting the gate  116  with respect to the valve body  114 . In a non-rising stem sluice gate valve embodiment, the thrust nut  124  is threaded complementarily to the stem  122  so that the thrust nut  124  and gate  116  ride up and down the stem  122  when the stem is turned. 
         [0032]    The sluice gate  116  is guided upward and downward by guide elements  130 , which are located on opposite sides of the sluice gate and travel upward and downward in tracks  148  running along the valve body  114 . Since the stem  122  and thrust nut  124  permit rotational  182  motion of the gate  116  around the axis of the stem  122 , the tracks  148  are designed to limit this rotational motion to reduce binding of the gate  116  during actuation of the valve. The tracks  148  in this embodiment only consist of rear-facing surfaces to limit the frontward movement of each guide element  130 . In a preferred embodiment, the guide elements  130  are pins. The tracks  148  preferably angle rearward toward the valve seat at an angle of about 5 degrees prior to the gate seating on the valve seat. 
         [0033]      FIG. 5  shows a sluice gate valve in a second embodiment of the present invention. The sluice gate valve  210  operates in a similar manner to the sluice gate valve  110  of  FIG. 3  and  FIG. 4 , except that ears  260 ,  262  are attached to a front surface of the sluice gate  216 . These ears  260 ,  262  slide along the front surfaces  264 ,  266  of rails on the valve body flanking the sluice gate. The front surfaces  264 ,  266  preferably angle rearward toward the valve seat  118  at the same angle as the tracks  148 . The ears  260 ,  262  limit the rearward motion of the sluice gate  216  during actuation. 
         [0034]      FIG. 6  through  FIG. 10  show a sluice gate valve in a third embodiment of the present invention. The sluice gate valve  310  includes a stuffing box  312 , a valve body  314 , and a sluice gate  316 . In a closed state, the sluice gate  316  sits in the valve seat  318  to block the orifice  320  of the sluice gate valve  310 . A mounting section  336  is mounted to the end of a pipe or other conduit to maintain the orifice  320  in a predetermined alignment with the conduit to be controlled by the sluice gate valve  310 . The valve  310  is preferably mounted using a plurality of bolts or screws. Turning of the stem  322 , which is threaded, actuates the sluice gate to open and close the valve. The sluice gate valve preferably includes a knob  338 , mounted on the end of the stem  322 , which is turned to actuate the valve. In the assembled state, the stem  322  passes through the stuffing box  312  and the neck  326  of the valve body. The stuffing box  312  is preferably mounted to the neck  326  by screws or bolts (not shown) through holes  340  in the stuffing box and holes  342  in the neck. A collar  339  and a bushing  341  are preferably mounted in a recess of the stuffing box  312  in the assembled sluice gate valve  310 . Although three screw holes for screws or bolts are shown and preferred, any number of screws or bolts may be used to mount the stuffing box to the neck within the spirit of the present invention. The stem  322  is coupled to the front-facing part of the sluice gate  316  through a pair of holes  344 ,  346 . 
         [0035]    A thrust nut  324  with a through-hole is mounted between the two holes  344 ,  346  on the gate  316  and maintains the stem  322  on the gate  316 . In a rising stem sluice gate valve embodiment, the thrust nut  324  and gate  316  maintain their vertical positions with respect to the stem  322 , and the stem  322  is threaded with respect to the stuffing box  312  or neck  326  such that the stem  322  rides up or down the with respect to the neck  326  as the stem  322  is turned, thereby vertically adjusting the gate  316  with respect to the valve body  314 . In a non-rising stem sluice gate valve embodiment, the thrust nut  324  is threaded complementarily to the stem  322  so that the thrust nut  324  and gate  316  ride up and down the stem  322  when the stem is turned. 
         [0036]    The sluice gate  316  is guided upward and downward by guide elements  330 , which are located on opposite sides of the sluice gate and travel upward and downward in tracks  348  running along the valve body  314 . Since the stem  322  and thrust nut  324  permit rotational motion of the gate  316  around the axis of the stem  322 , the tracks  348  are designed to limit this rotational motion to reduce binding of the gate  316  during actuation of the valve. The tracks  348  in this embodiment only consist of rear-facing surfaces to limit the frontward movement of each guide element  330 . In a preferred embodiment, the guide elements  330  are pins. The tracks  348  preferably angle rearward toward the valve seat at an angle of about 5 degrees prior to the gate seating on the valve seat. 
         [0037]      FIG. 11  shows an exploded view of a preferred stuffing box assembly of the present invention. Although the assembly is described with respect to the first embodiment, the assembly may be used with any of the described embodiments. The stuffing box  112  has three through-holes  140  for mounting the stuffing box to the neck  126  of the valve body using screws or bolts. A collar  139  and a bushing  141  are preferably mounted in a recess of the stuffing box  112  in the assembled sluice gate valve  110 . The collar  139  preferably has at least one roll pin  170  to hold the collar onto the shaft of the stem (not shown). The collar  139  preferably has a curved surface  172  facing the bushing  141 , and the bushing  141  preferably has a complementary curved inside cut surface  174  facing the collar  139  such that in the assembled sluice gate valve  110  the collar  139  inserts partially into the bushing  141 . The curved surfaces  172 ,  174  are preferably spherical in shape. The stuffing box assembly is designed to allow the stem to pivot up to a predetermined cone angle, thereby allowing a greater range of motion for the sluice gate  116  to reduce the frequency of incidences of binding during valve actuation. This pivoting of the stem permits predetermined amounts of top-to-bottom tilting or tipping  184  (see  FIG. 4 ) of the sluice gate away from the angling of the tracks, in-plane rotation  186  (see  FIG. 4 ) of the sluice gate clockwise or counter-clockwise, and combinations of these two types of motion during actuation, in addition to the rotational  182  (see  FIG. 4 ) motion available to the gate. The collar  139  pivots with respect to the bushing  141  along their complementary curved surfaces during this movement. 
         [0038]      FIG. 12  shows a schematic view of a pair of guide elements in a track in an embodiment of the present invention. In this embodiment, the first guide element  530  is the primary guide element traveling in the track  548 . The second guide element  550  limits the degree of tipping of the gate during actuation of the valve. The guide elements  530 ,  550  are preferably pins. The first guide element  530  is preferably similar to the previously-described guide elements  130 ,  330  in that it is located at or near the centerline of the gate and in its size. The track  548  is preferably similar in size and shape to the previously described track  348  with two side walls. The second guide element  550  is preferably smaller than and trailing the first guide element  530  by a predetermined distance and rides in the same track  548  as the first guide element  530 . The first guide elements  530 , the second guide elements  550 , and the tracks  548  are preferably designed such that in the assembled sluice gate valve, the amount of tipping of the gate is controlled during actuation of the valve to minimize binding, especially during seating and unseating. The tracks and guide elements preferably have mirror symmetry on the two sides of the gate, although they may be asymmetrical within the spirit of the present invention. 
         [0039]      FIG. 13  shows a schematic view of a pair of guide elements traveling in separate tracks in an embodiment of the present invention. In this embodiment, the first guide element  630  travels in the first track  648 , and the second guide element  650  travels in the second track  652 . The guide elements  630 ,  650  are preferably pins. The first guide element  630  and second guide element  650  are preferably similar to the previously-described guide elements  130 ,  330  in their relative sizes with respect to the tracks. The first guide element  630  is preferably located in front of the centerline of the gate. The second guide element  650  is located a predetermined distance behind the first guide element  630  and offset by a predetermined height so that its path does not cross the path of the first guide element  630 . The second guide element  650  is preferably located behind the centerline of the gate, more preferably a distance equal to the distance the first guide element  630  is in front of the center line. The first guide elements  630 , the second guide elements  650 , and the tracks  648 ,  652  are preferably designed such that in the assembled sluice gate valve, the amount of tipping of the gate is controlled during actuation of the valve to minimize binding, especially during seating and unseating. The tracks and guide elements preferably have mirror symmetry on the two sides of the gate, although they may be asymmetrical within the spirit of the present invention. 
         [0040]    In a preferred embodiment, a sluice gate valve of the present invention includes both the pivoting feature of  FIG. 11  and the pivoting feature of  FIG. 12  or  FIG. 13 . The combination of these two pivoting features allows predetermined amounts of rotational, frontward, rearward, and sideward motion of the sluice gate during actuation of the sluice gate valve, thereby reducing the likelihood of binding of the valve during actuation. 
         [0041]    Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.