Abstract:
An air motor ( 34 ) is arranged at a right angle to the valve stem ( 54 ), through a right angle gear drive ( 36 ) that provides torque amplification. A bracket ( 40 ) associates the motor with the valve body ( 48 ), having a flat ring ( 68 ) that fits over the valve body and has clearance notches ( 94 ) providing circumferential indexing. Semi-circular locking plates ( 66 ) are axially adjacent the ring and pivoted for swinging between a locking position where they fit in a groove ( 59 ) in the valve body and an unlocking position where they are free of the groove. Each locking plate has several through-holes through any of which a locking pin ( 42 ) can pass to lock the locking plate in locking position. Each locking pin protrudes axially beyond the ring to present interference with the valve body preventing the bracket from turning when the motor operates.

Description:
REFERENCE TO RELATED APPLICATION AND PRIORITY CLAIM 
   This application derives from the following commonly owned patent application, the priority of which is expressly claimed: Provisional Application No. 60/427,515, filed on 19 Nov. 2002 in the name of RICHARD FORTINO. 

   FIELD OF THE INVENTION 
   This invention relates to a valve closure system comprising a motor for turning a rotary actuator of a valve to operate the valve from open to closed. Such valve closure systems allow valves of vessels, such as cylinders and containers, that hold fluids, such as industrial gases for example, to be quickly operated from a remote location. 
   BACKGROUND OF THE INVENTION 
   Various types of transportable vessels are used for packaging various commercial and industrial gases at superatmospheric pressure. One type of vessel is a gas cylinder, an example of which is an elongate metal tank adapted to contain gas at relatively high pressure. An upper axial end of the cylinder has a neck containing an opening to the interior. A shut-off valve is mounted in closure of the neck opening. Another type is a container, a vessel that may have substantially larger volume than a cylinder. A container may have several such shut-off valves each mounted in closure of a respective opening in the container wall. 
   A representative shut-off valve comprises a first port fitted in sealed relation to an opening in a vessel wall, a second port, and a valve mechanism that is operable via an external actuator, handle, or tool, to allow and disallow fluid communication between the two ports. The second port is externally available for connection to a gas supply source when the cylinder is to be filled and for connection to a gas utilization system at a facility that uses gas stored in the cylinder. The valve mechanism comprises a stem that is rotated by the external actuator, handle, or tool to open and close the valve. An external actuator may be either manual or powered. An electric- or pneumatic-powered prime mover is an example of a power actuator. A wrench is an example of a hand tool for turning the valve stem. 
   The representative valve may be a globe style valve whose stem is rotatable more than one full turn between closed and full open positions. Opening the valve allows contained gas to pass from the vessel by entering the first port, flowing through the valve, and exiting via the second port. In such case, the first port forms a gas inlet connected to the vessel, and the second port a gas outlet. The gas outlet may be connected via a conduit to a point of use of the gas. 
   Such vessels can hold gases that may be considered hazardous, examples of such gases including chlorine and sulfur dioxide. A facility that utilizes one or more of such gases in a process, or processes, conducted at the facility may, for example, have any number of such vessels containing the same or different gases on the premises. When connected to a gas handling system at the facility, such vessels are able to deliver gas, or gases, into the system once their shut-off valves have been opened. Because of inherent characteristics of certain gases, vessels that contain them may be housed in locations that are remote from attending personnel, and/or the vessels may be in use at times when personnel are absent. 
   When a vessel, or vessels, is, or are, in use at a facility, and gas leakage is detected, it may be appropriate to shut off all vessels in an attempt to minimize further gas leakage. Accordingly, an automatic gas leak detection and valve shut-off system may be employed at a facility to address such a situation. Such a system may include a power actuator associated with the shut-off valve of each vessel. Examples of known valve closure systems include electromechanical actuators and pneumatic actuators. 
   Commonly owned U.S. Pat. No. 6,170,801 discloses a valve closure system that mounts on a gas-containing vessel in association with a valve having a rotatable stem that opens and closes the valve. The closure system comprises a mounting bracket and an air motor. With the valve open, the bracket is fit to the valve and a coupling on an external end of the air motor shaft is fit to the stem. The long axis of the air motor is coincident with the axis of the stem. When pressurized air is delivered to the air motor, the motor shaft rotates the stem in a sense that closes the valve. The long axis of the motor adds to the overall length of the closure system. With turning of the valve stem being in one-to-one correspondence (i.e. a 1:1 ratio) to turning of the motor shaft, the air motor must be able to deliver output torque corresponding to the torque requirement for the valve. 
   SUMMARY OF THE INVENTION 
   The present invention relates to further improvements in valve closure systems for fluid-containing vessels, the term “fluid” including both liquids and gases. Briefly, the invention comprises, in the disclosed preferred embodiment, an organization and arrangement where the long axis of the air motor is arranged at a right angle to the axis of the valve stem. The air motor is operatively coupled to the stem through a right angle gear drive that provides torque amplification. 
   The gear drive comprises a housing having opposite end faces from which opposite ends of a main shaft protrude. A bracket that comprises an assembly of several individual parts is assembled to the housing at a first of those two end faces. The bracket assembly serves to mount the closure system on the body of the valve. A coupler on the end of the main shaft that protrudes from the first end face aligns with and fits to the valve stem. The housing also has a side face that is disposed at a right angle to the first end face. The air motor is fastened to the side face. 
   The drive further comprises a stub shaft whose axis is transversely perpendicular to the axis of the main shaft. An outer end of the stub shaft protrudes from the housing at the side face, and the motor output shaft is coupled to that end of the stub shaft via a coupler. 
   Within the enclosed interior of the drive housing is a beveled gear set. One gear of the set is disposed on the interior end of the stub shaft, while the other gear of the set is disposed on the main shaft. Rotation of either one of the two shafts rotates the other via the gear set. 
   By providing the gear set with a suitable gear ratio, it becomes possible to multiply the air motor torque so that the actual torque that turns the valve shaft exceeds the torque that the motor would apply if it were directly coupled to the valve stem without the torque multiplication provided by the gear set. For a given valve closure torque requirement, the torque that an air motor is required to deliver can therefore be smaller when compared to the prior valve closure system of the commonly owned patent. This can enable a less expensive air motor to be used in certain applications. Because air motors may be commercially available in only certain sizes, the torque multiplication may preclude the need to choose an oversize motor and then use a pressure regulator to reduce the torque to a desired level. 
   Moreover, the mounting of the air motor with its long axis at a right angle to the axis of the valve stem may result in a more efficient use of space such as when the valve closure system is used with a gas cylinder that is supported horizontally in a rack rather than being stood upright. In such an installation, the valve closure system will protrude horizontally from the cylinder significantly less than if the air motor long axis is aligned with the valve stem, and therefore also horizontal. 
   A still further advantage of the invention is that the valve may be operated manually while the closure system remains mounted on a cylinder. This is because the protruding end of the main shaft of the gear drive opposite the shaft end coupled with the valve stem is readily accessible for turning by using a suitable handle or tool. 
   Still another advantage of the invention is that the valve closure system can be indexed on a valve at time of mounting so that the air motor points in a desired one of several available directions provided by the ability to index it. Once indexed in the desired orientation, locking plates of the bracket are swung closed onto the valve body, and locking pins are inserted through holes in the locking plates and holes in a base plate of the bracket that register with the holes in the locking plates when the latter are closed. Because the mounting circumferentially girdles the valve body, it is not prone to cocking on the valve body when the air motor operates. 
   The preferred embodiment of the inventive closure system is well suited for use with known, and commonly used, gas shut-off valves, although certain principles are generic to use of the inventive system with different forms of shut-off valves. Certain principles of the invention may also extend to valve closure systems in which the fluid storage medium is a form of storage vessel other than the particular container and cylinder vessels mentioned above. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     The accompanying drawings, which are incorporated herein and constitute part of this disclosure, illustrate a presently preferred embodiment of the invention, and together with the written description given herein disclose principles of the invention in accordance with a best mode contemplated at this time for carrying out the invention. 
       FIG. 1  is a perspective view showing the general organization and arrangement of one embodiment of valve closure system according to the invention. 
       FIG. 2  is a bottom view of  FIG. 1  as taken in the direction of arrows  2 — 2  in the latter Figure. 
       FIG. 3  is a front elevation view in the direction of arrows  3 — 3  in FIG.  2 . 
       FIG. 4  is a side elevation view in the direction of arrows  4 — 4  in FIG.  3 . 
       FIG. 5  is a perspective view of one of the parts shown by itself. 
       FIG. 6  is a plan view of the part of  FIG. 5 , taken in the direction of arrows  6 — 6  in the latter Figure. 
       FIG. 7  is a side view in the direction of arrows  7 — 7  in FIG.  6 . 
       FIG. 8  is a perspective view of another one of the parts shown by itself. 
       FIG. 9  is a plan view of the part of  FIG. 8 , taken in the direction of arrows  9 — 9  in the latter Figure. 
       FIG. 10  is a side elevation view in the direction of arrows  10 — 10  in FIG.  9 . 
       FIG. 11  is a side elevation view in the direction of arrows  11 — 11  in FIG.  9 . 
       FIG. 12  is a perspective view of still another one of the parts shown by itself. 
       FIG. 13  is a plan view of the part of  FIG. 12 , taken in the direction of arrows  13 — 13  in the latter Figure. 
       FIG. 14  is a side elevation view in the direction of arrows  14 — 14  in FIG.  13 . 
       FIG. 15  is a side elevation view in the direction of arrows  15 — 15  in FIG.  13 . 
       FIG. 16  is an elevation view of still another part by itself. 
       FIG. 17  is a top view of FIG.  16 . 
       FIG. 18  is a bottom view of FIG.  16 . 
       FIG. 19  is a longitudinal view of still another part by itself. 
       FIG. 20  is an end view of FIG.  19 . 
       FIG. 21  is a longitudinal view of still another part by itself. 
       FIG. 22  is a left end view of FIG.  21 . 
       FIG. 23  is an exploded perspective view of a bracket assembly formed, in part, by the parts of  FIGS. 8-18  and including additional parts. 
       FIG. 24  is a longitudinal view of a gear drive by itself. 
       FIG. 25  is a perspective view of an air motor. 
       FIG. 26  is an enlarged longitudinal view of the air motor of FIG.  25 . 
       FIG. 27  is a bottom end view in the direction of arrows  27 — 27  in FIG.  26 . 
       FIG. 28  is a view showing the closure system associated with a valve, portions of the closure system shown in this Figure being different from previous Figures. 
       FIG. 29  is a perspective view of the valve by itself rotated lightly from the orientation shown in FIG.  28 . 
       FIG. 30  is an enlarged view in circle  30  of FIG.  28 . 
       FIG. 31  is an enlarged view in the direction of arrows  31 — 31  in FIG.  28 . 
       FIG. 32  is a right side elevation view of FIG.  31 . 
       FIG. 33  is a perspective view of another part shown in FIG.  28 . 
   

   DETAILED DESCRIPTION 
   The drawing Figures illustrate a presently preferred embodiment of cylinder valve closure system  30  according to principles of the invention intended for association with a cylinder valve  32 , as in FIG.  28 . System  30  includes an air motor  34  (FIGS.  25 - 27 ), a gear drive  36  (FIG.  24 ), a female input drive coupler  37  (FIGS.  19 - 20 ), a female output drive coupler  38  (FIGS.  21 - 22 ), and a bracket  40  (partly shown in FIG.  23 ). Additional parts include locking pins  42 ,  44  (FIG.  23 ), and various fasteners, not all of which appear in the Figures. 
   Valve  32 , as shown by itself in  FIG. 29 , is a commercially available cylinder tank shut-off valve that comprises a body  48  having a first port  50  at the bottom and a second port  52  at a side. Port  50  is adapted to fit in sealed closure of an opening in a neck at the top of a gas cylinder (not shown). Port  52  is adapted for connection to a gas supply source when the cylinder is to be filled with gas. When the cylinder is in use at a facility, port  52  is connected to a gas handling system through which gas can flow from the cylinder to a point of use at the facility. 
   Valve  32  further includes an operating mechanism comprising a valve element within body  48  that is operated to open and close an internal gas flow path between ports  50  and  52 . The valve element is operated by turning an actuator, which for the illustrated valve, is a stem  54  on the exterior of body  48 . The turning of stem  54  occurs about an axis  56 . Stem  54  has a polygonally-shaped transverse cross section (a square shape for example) that can be engaged by a complementary shaped tool or socket for turning the stem. At the location where stem  54  protrudes from valve body  46  is a hexagonal-shaped head  58  that is concentric with axis  56 . Immediately below, and concentric with head  58 , is a circular cylindrical wall  57  that endows valve body  48  with a circular groove  59  between head  58  and a lower generally rectangular body portion  60 . 
   Bracket  40  comprises an assembly of one adapter plate  62 , two posts  64 , two locking plates  66 , and one base plate  68 .  FIGS. 5-7  show detail of adapter plate  62 ;  FIGS. 8-11  show detail of base plate  68 ;  FIGS. 12-15  show detail of a locking plate  66 ; and  FIGS. 16-18  show detail of a post  64 . 
   Each post  64  comprises a shoulder  70  that joins a larger diameter portion  72  forming most of the post length from a smaller diameter portion  74 . Tapped holes  76 ,  78  are in opposite ends of each post. 
   Each locking plate  66  has a generally semi-circular shape centered on an imaginary axis that in closure system  30  is coincident with axis  56 . It also has a uniform thickness. At a proximal end of its generally semi-circular extent, locking plate  66  has a somewhat semi-circular tab, or ear,  79  that contains a through-hole  80 . Beyond through-hole  80  in the counterclockwise direction in  FIG. 13 , locking plate  66  has a succession of three smaller through-holes  82 . At the distal end opposite tab  79 , locking plate  66  a concave recess  84 . Radially inward of recess  84 , plate  66  has a small projection  86 . The end edge surface of plate  66  formed by recess  84  has a shape that is essentially congruent to the end edge surface formed by tab  79 . Radially inward of tab  79  is a recess  88  forming an end edge surface that is essentially congruent to the end edge surface formed by projection  86 . 
   Each of the two locking plates  66  is associated with a corresponding post  64  by fitting the smaller diameter portion  74  of the post to through-hole  80 , disposing base plate  68  against the ends of the post portions  74  with countersunk through-holes  90  that are diametrically opposite each other in base plate  68  aligned with tapped holes  76  in the posts, and then securely fastening the base plate to the posts using fasteners (not shown) that pass is through through-holes  90  and thread into holes  76 . The thickness of each locking plate  66  is slightly less than the length of each post portion  74  so that the locking plates are effectively hinged for swinging motion on the posts, as suggested by FIG.  23 . 
   Base plate  68  is essentially a circular ring of uniform thickness centered on axis  56  in closure system  30 . It has modest radial protrusions  92  at the locations of through-holes  90 . Between protrusions  92 , the width of the ring is nominally uniform, but the inside diameter is interrupted by a succession of three notches  94  in each semi-circumference. When locking plates  66  are swung to the closed position show in  FIGS. 1 and 28 , each through-hole  82  registers with a respective notch  94 . 
   Adapter plate  62  has a generally uniform thickness and a generally rectangular shape in plan. It serves to adapt bracket  40  for mounting on gear drive  36 . At the midpoints of its shorter side margins, plate  62  has countersunk through-holes  96  that register with tapped holes  78  in posts  64 . Fasteners (not shown) pass through through-holes  96  and are tightly threaded to holes  78  to secure adapter plate  62  to the posts. 
   At its four corners, adapter plate  62  has through-holes  98  by which the adapter plate fastens to a flange  100  of a housing  102  of gear drive  36  using fasteners  104 . At its center, adapter plate  62  has a clearance hole  106  that enables operative coupling of gear drive  36  with valve stem  54  using coupler  38 . 
   Gear drive housing  102  has opposite end faces from which protrude opposite ends  110 ,  112  of a main shaft  114 . Flange  100  surrounds protruding shaft end  112  at one end face. A further flange  116  of housing  102  surrounds protruding shaft end  110  at the opposite end face. Bracket  40 , which includes adapter plate  62  as part of the overall assembly mounted on gear drive  36 , serves to mount closure system  30  on valve body  48 . Coupler  38  is assembled to shaft end  112  for aligning with and fitting to valve stem  54  when the closure system is in place. 
   Housing  102  also has a side face comprising a flange  120  that is disposed at a right angle to flanges  100 ,  116 . A flange  122  of air motor  34  is fastened to flange  120  for mounting the air motor on the gear drive. 
   Gear drive  36  further comprises a stub shaft  124  whose axis is transversely perpendicular to the axis of main shaft  110 . One end of stub shaft  124  protrudes from housing  102  where it is surrounded by flange  122  and coupled by coupler  37  to the air motor shaft. 
   Within the enclosed interior of housing  102  is a beveled gear set  126 . One gear  128  of the set is disposed on the inner end of stub shaft  124 , while the other gear  130  of the set is disposed on the interior of main shaft  110 . Rotation of either one of the two shafts rotates the other via gear set  126 . 
   The gear set is provided with a suitable gear ratio that multiplies the air motor torque so that the actual torque that turns the valve shaft exceeds the torque that the motor would apply if it were directly coupled to the valve stem without the torque multiplication provided by the gear set. For a given valve closure torque requirement, this means that the torque that an air motor delivers can be smaller when compared to the prior valve closure system of the commonly owned patent mentioned above. 
   Air motor  34  is a commercially available air motor having an output shaft  143  at the one axial end containing flange  122 . A fitting  144  is installed in an air supply port  146  at the opposite axial end. A pneumatic line (not shown) connects to fitting  144  to provide pressurized air for operating motor  34  such that the motor output shaft turns in the proper sense for closing the valve when called upon to do so. 
   Both female drive couplers  37 ,  38  are generally cylindrical. Coupler  37  adapts the square drive of the motor shaft to that of the outer end of stub shaft  124 . Coupler  38  adapts the square drive of gear drive shaft end  112  to that of the valve stem. Coupler  38  has an off-center transverse through-hole  150  that intersects the portion that fits onto shaft end  112 . A spring pin  152  ( FIG. 28 ) is pressed into that hole after the coupler is fit onto the shaft end. 
   The shaft end has an elongate notch  154  parallel to the shaft length, and spring pin  152  passes through notch  154 , causing the coupler to be kept on the shaft end, but allowing the coupler to position itself axially along the shaft end. The lost motion allows for some tolerance in length of valve stem and extent of stem displacement while turning. The limited displacement travel serves to accommodate axial travel of the valve stem as the stem is being rotated, but it does not allow coupler  38  to lose driving engagement with the valve stem while the system remains installed. Because notch  154  is machined in an outer surface of the shaft end, rather than through the shaft end, the shaft end is endowed with increased strength. 
     FIG. 28  shows valve closure system  30  in operative association with shut-off valve  32 , although system  30  differs in certain respects that will be described later. Locking plates  66  are swung closed to lodge their inner margins in groove  59 . Locking pins  42 ,  44  are inserted into appropriate ones of holes  82  with their distal ends passing through base plate  68  and clearance to the base plate being provided by the registration of notches  94  with holes  82 . The distal end of one of the two pins presents an interference to the side wall of valve port  52 . The two locking plates fit together circumferentially girdling the valve body at groove  59 , and base plate  68  also circumferentially girdles the valve body around body portion  60 . 
   With valve  32  open, operation of air motor  34  acts through gear drive  36  to turn the valve stem in a sense that closes the valve. The interference presented to the side wall of valve port  52  by the distal end of one of the two locking pins reacts the torque to prevent bracket  40  from turning on the valve body. 
   Removal of the closure system from the valve can be easily accomplished by the following steps. Locking pins  42 ,  44  are extracted using the pull-rings  158  at their proximal ends and removed from the assembly, thereby unpinning locking plates  66  from base plate  68 . The locking plates can now be swung clear of the valve groove, and the bracket disengaged from the valve by bodily moving it along the direction of axis  56  away from the valve. 
   Installation of valve closure system  30  can be made by a reverse sequence of steps. The closure system is installed on a shut-off valve when the valve is open. The shape imparted to the inside edge of base plate  68  by notches  94  endows bracket  40  with the ability to be indexed on the valve body at several different orientations about axis  56 . With locking plates  66  swung open, bracket  40  is fit onto the valve body at the desired degree of indexing. Then the locking plates are swung closed, and locking pins  42 ,  44  inserted. 
   Because system  30  is intended as strictly a valve closure system, motor  34  is rendered uni-directional in the manner described above so that when pneumatic power is applied to port  146  via fitting  144 , shaft  110  will rotate only in the direction that produces valve closing. Any reaction torque that might tend to turn the bracket on the valve body when motor  34  is operated to close shut-off valve  32  will result in abutment of one of the locking pins with the side of the valve port that prevents bracket turning. The system is however operable bi-directionally for both opening and closing valve  32  manually by engaging a suitable tool with shaft end  114  and turning it in the desired direction. Therefore, if the motor has been operated to close the valve, the valve can be manually re-opened without having to remove the system from the valve. Making motor  34  capable of bi-directional operation would of course also enable the motor to both open and close the valve. 
   The system  30  shown in  FIG. 28  differs from the previous Figures in that it has a modified form of gear drive  36 . The same reference numerals serve to identify parts previously described. Housing  102 , shown by itself in  FIGS. 31 and 32 , no longer has distinct flanges, thereby eliminating the need for adapter plate  62  and air motor mounting flange  122 . A cylindrical wall  160  of housing  102  surrounds the protruding end of input shaft  124 . 
   Air motor  34  comprises a cylindrical housing  162  that extends axially beyond the end of motor shaft  143  to telescopically fit over wall  160 . Motor  34  is secured to the gear drive housing via three fasteners  164  arranged 120° apart to pass through holes  166  in housing  162  and thread into holes  168  in wall  160 . As the motor is being telescoped over wall  160 , the motor shaft  143  comes into operative coupling with input shaft  124 . 
   The axes of shafts  114 ,  124  intersect at 90° within the gear drive housing interior, and each shaft is journaled on gear drive housing  102  by ball bearing assemblies  170 . 
   While a presently preferred embodiment of the invention has been illustrated and described, it should be appreciated that principles of the invention are applicable to all embodiments that fall within the scope of the is claims that follow hereinafter.