Abstract:
Safety shutoff apparatus can close a valve using a pressure operable device coupled to and acting upon the valve. The proximal end of a pressure line is coupled to the pressure operable device for applying fluid pressure thereto in order to operate the pressure operable device. A soluble plug at the distal end of the pressure line can seal it in order to maintain pressure at the pressure operable device. By placing the soluble plug next to an object that is subject to leaking, the soluble plug can dissolve when a leak occurs and release the pressure in the pressure line. The released pressure results in closure of the valve when mechanical movement is produced by the pressure operable device in response to the release of pressure.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to safety shutoff apparatus that is able to protect against leaks. 
   2. Description of Related Art 
   Appliances such as water heaters, clothes washing machines and the like can spontaneously leak. Leaks can also come from worn or defective valves or from pipes or other plumbing fixtures that burst when frozen. If the owner is absent the leak can cause flooding and substantial damage. 
   Various emergency shutoff valves have been proposed that employ a water sensor that operates another device that is capable of closing a valve. The drawback with these designs is that the sensors or the shutoff device is relatively complicated and may require an external source of power such as electricity. Also, these devices are not easily adapted to monitoring leaks at remote locations or multiple locations. 
   In the housing 22 of U.S. Pat. No. 3,920,031 spring biased plunger 26 presses against a plug 30 made of “sugar, salt, or the like.” Column 3, lines 20-21. A leak from the water heater can dissolve the plug and pull wire 36 to release catch 68 from the notch 64, so that the valve is shut off by means of coil spring 58. 
   In U.S. Pat. No. 6,024,116 a valve stem 36 is held in place by flexible fingers 106 that press into grooves 104 and are held in place by a reinforcing paper collar 38. Paper collar 38 is water-soluble and leakage from a hot water heater will soften collar 38 to the point where it will deform or tear and thereby release valve stem 36, thereby closing the valve. 
   In U.S. Pat. No. 4,877,049 the timer on a washing machine starts an air compressor 16/17 to open hydraulically operated valves 5. Water from a leak lifts float 20 to open electrical contacts 19 and stop air compressor 16/17, thereby closing valves 5. See also U.S. Pat. No. 4,141,533 (solenoid valve actuated to supply pressure to a cylinder that closes a valve). 
   In U.S. Pat. No. 6,206,337 a retrofit device is clamped to a water supply pipe to operate a shut off valve. A sensor can electrically operate solenoid 35 to release a catch 40 so that spring 32 can swing handle 15 and close valve 60. 
   In U.S. Pat. No. 5,771,916 leaking water enters a containment chamber of a shut off valve and causes block 82 to expand in order to swing lever 84 and release arm 70 so that spring 78 can close the valve. 
   In U.S. Pat. No. 6,253,785 float 40 lifts hook 34 to release valve handle 32 so that spring 28 can close shut off valve 24. 
   In U.S. Pat. No. 4,437,482 a water soluble band 24 that wraps around fingers 26 and 28 can dissolve and release spring-loaded shuttle 18 to close port 20 and prevent water intrusion that may otherwise damage a gas leak detector. 
   In  FIG. 7  of U.S. Patent Application Publication No. U.S. 2002/0074042 a valve designed to close in response to high water flow rates is initially kept open after installation by a water-soluble plug 300. 
   See also U.S. Pat. No. 5,253,619 (electrically controlled hydraulic actuator operates an engine valve). 
   Accordingly, there is a need for an improved safety shutoff apparatus that is able to simply and reliably protect against leaks. 
   SUMMARY OF THE INVENTION 
   In accordance with the illustrative embodiments demonstrating features and advantages of the present invention, there is provided a safety shutoff apparatus for closing a valve. The apparatus has a pressure operable device coupled to the valve for acting upon the valve. Also included is a pressure line having a distal end and a proximal end. The proximal end of the pressure line is coupled to the pressure operable device for applying fluid pressure thereto in order to operate the pressure operable device. the apparatus also has a soluble plug at the distal end of the pneumatic line for sealing the pressure line in order to maintain pressure through the pressure line at the pressure operable device. 
   In accordance with another aspect of the invention, a method is provided for closing a valve with a pressure operable device that is coupled to a pressure line whose distal end is sealed with a soluble plug. The method includes the step of pressurizing the pressure line sufficiently to cause the pressure operable device to maintain the valve in an open condition. Another step is contemporaneously placing the soluble plug next to an object that is subject to leaking to allow in response to leaking from the object dissolution of the soluble plug and release of pressure in the pressure line. The method also includes the step of closing the valve when mechanical movement is produced by the pressure operable device in response to pressure being released from the pressure line. 
   By employing apparatus and methods of foregoing type, an improved safety shutoff apparatus is achieved. In one preferred embodiment, a spring attached to the operating handle of a shutoff valve biases the valve toward a closed condition. A catch engages the valve handle and holds the valve handle in an open position. Preferably, the catch is attached to the piston rod of a pneumatic cylinder that holds the catch in the engaged position so long as the cylinder receives air pressure of about 5 psi. The pressure line attached to the cylinder is routed to the vicinity where a leak may occur. The distal end of the pressure line is sealed with the soluble plug that can dissolve when a leak occurs and release the pressure in the pressure line. In response, the cylinder releases the preferred catch so that the spring can pull the valve handle to the off position. 
   Embodiments are disclosed in which a torsion spring is used instead of an extension spring in order to directly rotate the valve member. That embodiment can use a cam that is rotated by the pneumatic cylinder away from the valve handle so the torsion spring can close the shutoff valve. Instead of a pneumatic cylinder, other embodiments may use a bellows, a diaphragm, a bladder, and the like. 
   Some embodiments may employ a pressure line-that has multiple soluble plugs at spaced positions along either a single pressure line or at the ends of multiple branches of the pressure line. These multiple plugs can protect against leaks at different locations in the vicinity of different objects such as a water heater, clothes washer, or other device. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above brief description as well as other objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of presently preferred but nonetheless illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings, wherein: 
       FIG. 1  is a perspective view of a safety shutoff apparatus installed on a water shutoff valve in accordance with principles of the present invention; 
       FIG. 2  is a side view of another safety shutoff apparatus that is an alternate to that of  FIG. 1 ; 
       FIG. 3  is a cross-sectional view taken along line  3 — 3  of  FIG. 2  showing an inner portion of a torsion spring drive apparatus with the spring cover removed for illustrative purposes; 
       FIG. 4  is a sectional view taken along line  4 — 4  of  FIG. 3 ; 
       FIG. 5  is a side view of another safety shutoff apparatus that is an alternate to that of  FIG. 2  with portions of the valve broken away for illustrative purposes; 
       FIG. 6  is a cross-sectional view taken along line  6 — 6  of  FIG. 5 ; 
       FIG. 7  is a schematic perspective view of the overall installation of the apparatus of  FIG. 1  or its alternatives; 
       FIG. 8  is a detailed, longitudinal sectional view of a soluble plug in a sleeve installed in the distal end of a pressure line; 
       FIG. 9  is a detailed, longitudinal sectional view of a device that is an alternate to that of  FIG. 8 ; 
       FIG. 10  is a detailed, longitudinal sectional view of a device that is an alternate to that of  FIG. 8 ; 
       FIG. 11  is a plumbing diagram of the pressure line of  FIG. 7  with branches fitted with soluble plugs and other devices, and with portions of the pressure line broken away for illustrative purposes; 
       FIG. 12  is a schematic diagram of an apparatus that is an alternate to that of  FIG. 1 ; 
       FIG. 13  is a cross-sectional diagram of an accumulator that may communicate with components described herein; 
       FIG. 14  is a cross-sectional diagram of an accumulator that is an alternate to that of  FIG. 13 ; 
       FIG. 15  is a schematic diagram of an apparatus that is an alternate to that of  FIG. 1 ; 
       FIG. 16  is a schematic diagram of an apparatus that is an alternate to that of  FIG. 1 ; 
       FIG. 17  is a schematic diagram of an apparatus that is an alternate to that of  FIG. 1 ; 
       FIG. 18  is a schematic diagram of an apparatus that is an alternate to that of  FIG. 1 ; and 
       FIG. 19  is a schematic diagram of an apparatus that is an alternate to that of FIG.  1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIG. 1  the illustrated safety shutoff apparatus operates on a shutoff valve  10  coupled between water supply pipes  12  and  14 . The valve  10  is operated by a handle  16  that attaches to a movable member  18  of the valve. Handle  16  is shown in the closed condition, the open position being shown in phantom. Handle  16  is shown with angularly spaced arms  16 A and  16 B that can engage and be stopped by stationary structure  11  on the body of valve  10  when the valve handle is fully open and fully closed, respectively. 
   A split clamp  19  is bolted around pipe  14 . A standoff is shown as a plate  20  bolted to clamp  19  and having an upper hole  22 . An extension spring  24  is attached between hole  22  of standoff  20  and hole  26  of handle  16 . Spring  24  tends to pull handle  16  into the illustrated closed position and therefore acts as a biasing device. 
   Another split clamp  28 , identical to clamp  19 , is secured around pipe  12  to support one branch of L-shaped bracket  30 . The other branch of bracket  30  supports pneumatic cylinder  32  that acts as a pressure operable device. Piston rod  34  extending from cylinder  32  is attached to a split clamp  36 , which supports an arm  38  in a position transverse to rod  34 . The distal end of arm  38  has a transverse pin  40  that acts as a catch. Specifically, when handle  16  is rotated to the open position  42 , catch  40  can engage an edge of handle  16  and keep valve  10  in the open condition. While catch  40  is shown engaging an edge of handle  16 , in some embodiments the catch may engage a slot other opening in handle  16 , for example, the slot  44  shown in phantom in this Figure. 
   The proximal end of a pneumatic pressure line  46  connects to cylinder  32 . A modest pressure of about 5 psi (pounds per square inch) can keep rod  34  extended so that pin  40  remains in a position engaging an edge of handle  16 . If the pressure in line  46  is released rod  34  (which is spring biased) retracts so that pin  40  moves axially (that is, in a direction parallel to the axis of rotation of movable member  18 ). It will be appreciated that pressures other than 5 psi can be employed depending upon the forces involved, the desired immunity from pressure decay, the size of the, pneumatic components, etc. 
   Referring to  FIGS. 2-4 , previously mentioned valve  10  is shown connected between pipes  12  and  14 . Handle  16  is as before except that previously mentioned slot  44  is in fact implemented in this embodiment. The prominent lobe of cam  48  is shown inserted in slot  44  of handle  16 . Cam  48  is pivotally mounted in opposing arms of clamp  50 , which is secured to pipe  12 . A pneumatic cylinder  52  similar to the one previously described is attached parallel to pipe  12  by clamp  54 . Piston rod  56  of cylinder  52  is attached by clevis  58  to cam  48  and can thereby rotate cam  48  into the released position  58  shown in phantom. It will be appreciated that in some embodiments piston rod  56  may retract and thereby rotate cam  48  in the opposite direction. When cam  48  is thus rotated, it leaves slot  44  of handle  16 , leaving the handle free to rotate from the illustrated open position. 
   In this embodiment handle  16 , when released, can be rotated to a closed position by torsion spring  60 . Torsion spring  60  encircles a spool-like stator comprising a spindle  62  affixed to an inner flange  64 . Projecting from inner flange  64  is an abutment arm  66  having a bent tip designed to engage stationary structure  11  on valve  10 . Spindle  62  is a slender sleeve capped by an outer flange  68  and rotatably mounted on a bolt  70  that is screwed into movable member  18  of the valve  10 . Flanges  68  and  64  are affixed so that they rotate together. 
   The outer end  60 A of torsion spring  60  is captured in a notch  72 A of disk  70 , which is secured to flange  68  by pin  74 . The pin  74  can be removed to change the relative angular orientation between disk  72  and flange  68 . For example, a number of angularly spaced apertures in flange  68  accommodate a repositioning of pin  74 . 
   The inner end  60 B of torsion spring  60  is captured in a notch  76 A of rotor  76 . If torsion spring  60  is wound and the outer end  60 A is kept fixed, the inner end  60 B tends to rotate rotor  76  clockwise (as viewed in FIG.  3 ). Radially extending from rotor  76  is a driving arm  78  having a bent tip designed to engage an edge of valve handle  16 , so that arm  78  can rotate handle  16 . 
   Torsion spring  60  is installed by first setting the angular relationship between disk  72  and flange  68 , which establishes the neutral relative angular orientation between the arms  66  and  78  (that is, the angular displacement between arms  66  and  78  when torsion spring  60  is unwound to the extent possible). Next, torsion spring  60  is wound by rotating arm  78  counterclockwise relative to arm  66  (as viewed in FIG.  3 ). 
   While arms  66  and  78  are kept in this wound position, bolt  70  is screwed into movable member  18  with arms  66  and  78  abutting elements  11  and  16 , respectively, as shown in  FIGS. 2-4 . Consequently, torsion spring  60  will tend to drive arm  66  into abutment with stationary structure  11 , while arm  78  will engage in an edge of valve handle  16  and will tend to drive handle  16  to a closed position. Once the torsion spring  60  is thus installed, cover  80  may be placed over the spring. Accordingly, when rod  56  extends and rotates cam  48  out of slot  44 , torsion spring  60  can rotate arm  78  to drive handle  16  into a closed position. 
   Referring to  FIGS. 5 and 6 , elements identical to those shown in  FIGS. 2-4  have the same reference numerals, while elements only similar to those shown in  FIGS. 2-4  have the same reference numerals but marked with a prime (′). In particular, the previously described torsion spring (spring  60  of  FIG. 2 ) is mounted as before inside cover  80 ′ with spindle  62  rotatably mounted on bolt  70 , which is threaded into movable member  18 . 
   Here however, the torsion spring drives a modified rotor  76 ′ and spindle  70  is affixed to a modified flange  64 ′. In particular, rotor  76 ′ has a modified driving arm  78 ′ that supports an integral spur  82 . The modified flange  64 ′ has a modified abutment arm  66 ′ that supports an integral spur  84 . Spurs  82  and  84  project toward each other and are shown overlapping in FIG.  6 . Spurs  82  and  84  each have a distal hole, which holes are shown receiving pin  86  in FIG.  6 . Pin  86  is attached to piston rod  88  of pneumatic cylinder  90 , which is held by strap  92  to cover  80 ′. Accordingly, cylinder  90  can retract pin  86  so that arm  78 ′ is free to rotate and drive valve handle  16  from the illustrated open position 90° to a closed position. 
   Referring to  FIG. 8 , sleeve  94  is inserted into the distal end of previously mentioned pressure line  46 . Line  46  may be a flexible hose made of rubber, silicone, or other materials. The sleeve  94  may be a short section of tubing made of a metal (e.g., copper), plastic, or other materials. 
   A soluble plug  96  is sealed inside sleeve  94 . Plug  96  may be made by finely grinding a soluble material, which is then wetted to form a paste that is then pressed into sleeve  96  and allowed to dry. Instead of forming a paste, some ground materials can be poured into sleeve  94  and compressed into a solid mass. In still other embodiments, the plug  96  can be formed in a separate mold and then inserted into sleeve  94 . 
   It is desirable to coat the inside of sleeve  94  with a sealant such as an adhesive to prevent leaks between plug  96  and sleeve  94 . Plug  96  can be made of any one of a variety of soluble substances such as aspirin, sugar, salt, etc. that can dissolve in water and thereby release the pressure inside line  46 . For embodiments that are designed to respond to fluids other than water, plug  96  will be chosen to be soluble in that other fluid. 
   In some embodiments, sleeve  94  may be eliminated and plug  96  may be made with a diameter that allows plug  96  to be snugly inserted into pressure line  46  in order to close and seal the pressure line  46 . 
   Referring to  FIG. 9 , pressure line  46 ′ is modified to have external threads on its distal end. An alternate sleeve  98  is internally threaded at its proximal end to receive line  46 ′. Sleeve  98  has on its distal end an inwardly diverging throat  100  that is preferably frustoconical. A frustoconically shaped soluble plug  102  is sealingly fitted in frustoconical throat  100 . Plug  102  may be formed in a manner similar to that previously described in connection with FIG.  8 . 
   Since plug  102  and throat  100  are similarly tapered, pressure applied from line  46 ′ will tend to press plug  102  outwardly, which will tend to wedge the plug more tightly in throat  100 , thereby producing a tighter seal. 
   Referring to  FIG. 10 , another sleeve  104  has an inner chamber  106  that converges into a male fitting  108  with an axially spaced plurality of annular barbs  110  designed to seal inside a flexible hose (e.g., hose  46 ). A stopper  108  is slidably mounted inside chamber  106 . A soluble plug  110  is fitted inside a larger outer chamber  112  that communicates with inner chamber  106 . The side walls of chamber  112  are perforated by a plurality of side orifices  114 , which increase the exposure of soluble plug  110 . 
   With this arrangement, water or other fluids can gain access to soluble plug  110  through the side orifices  114  or through the large distal opening in sleeve  104 . Once plug  110  has dissolved, the pressure in chamber  106  ejects stopper  108  and the pressure in chamber  106  is discharged through orifices  114  or the open distal end of sleeve  104 . This arrangement has the advantage that plug  110  does not need to provide the sealing function, but merely needs to hold in place stopper  108 , which then performs the sealing function. 
   Referring to  FIG. 11 , previously mentioned pressure line  46  is shown connected to one branch of T fitting  116 , whose other two branches are connected to lines  118  and  120  so that line  46  can communicate with those lines. The distal end of line  120  connects to one branch of a Y fitting, whose other two branches connect to lines  126  and  128 . The distal end of line  128  connects to one branch of T fitting  130  whose opposite branch connects to line  132 . The other branch  134  of T fitting  130  is a port with a soluble seal and may be a structure similar to the sleeve  94  and soluble plug  96  described in connection with FIG.  8 . The distal ends of lines  126  and  132  are also ports with soluble seals and may be fitted with a sleeve  94  and soluble plug  96  as was described in connection with FIG.  8 . 
   Line  118  is used as a service branch and connects to a fitting  122  that is built like the valves found on the inner tubes used in automobile or bicycle tires. Accordingly, fitting  122  can be used with a pressure source  123  (e.g., a bicycle pump) to pressurize lines  46  and  120 , which will in turn pressurize the branches served by lines  126  and  128 . 
   To facilitate an understanding of the principles associated with the foregoing apparatus, its operation will be briefly described in connection with the embodiment of FIG.  1  and the layout diagram of FIG.  7 . It will be appreciated that the other embodiments of  FIGS. 2-6  will operate in a similar manner. 
   If the apparatus of  FIG. 1  is installed as shown, handle  16  is held in the closed position by extension spring  24 . Assuming there is no pressure in line  46 , rod  34  will be retracted by cylinder  32  so that pin  40  is retracted as well. Accordingly, handle  16  can be swung 90° to the closed position  42  without interference. 
   Next, pressure is applied to line  46  causing rod  46  to extend so that pin  40  will extend over the edge of handle  16  thereby holding it in the open position  42  against the urging of spring  24 . If rod  34  and pin  40  were already extended before the handle  16  is swung to the open position  42 , the user may temporarily remove pin  40  so that handle  16  can be swung to the open position  42  before reinstalling pin  40 . 
   In  FIG. 7  previously mentioned pipe  12  is shown as a water supply connected to a water main outside the building. The apparatus illustrated in  FIG. 1  is hidden inside housing H in FIG.  7 . Previously mentioned pipe  14  is shown as an outlet that can supply water to various objects, such as a water heater W or clothes washing machine C. 
   Line  46  is shown communicating with first branch  128 , which has a first port  134  with a soluble seal and a second port  94  with a soluble seal  96 . Port  134  is adjacent to water heater W while port  94  is adjacent to clothes washing machine C. The second branch  126  terminates in a port  94  having a soluble seal  96  that can respond to water in another vicinity; for example, to water that may overflow from a sink at this level or some upper level. 
   If water leaks from one of the objects W or C or elsewhere, the soluble seal in one of the previously mentioned ports will dissolve. For the ports shown in  FIGS. 8 and 9  the soluble plugs will simply progressively erode until so weakened that internal pressure will simply dislodge the remaining plug fragment. For the embodiment of  FIG. 10  dissolution of plug  110  will allow stopper  108  to be ejected by the pressure inside chamber  106 . 
   Once the soluble plug dissolves, the pressure is released in lines  46 ,  126 , and  128 . Consequently, cylinder  32  ( FIG. 1 ) retracts rod  34  under the urging of its internal spring (not shown). This retraction causes catch  40  to retract away from and release handle  16 . Next, spring  24  is able to swing handle  16  to the closed position shown in FIG.  1 . This shuts off the supply of water so that no further leakage can occur through objects W and C. 
   Once the leak is repaired, a new soluble plug can be installed in the affected port. For the embodiment of  FIG. 8  empty sleeve  84  is removed and replaced with another sleeve that contains an intact soluble plug. A similar replacement is performed if the affected port is the in-line fitting  130  (FIG.  11 ). For the embodiment of  FIG. 9  empty sleeve  98  is unthreaded and replaced with a new sleeve containing an intact plug. For the embodiment of  FIG. 10  male fitting  108  is pulled from the associated pressure line so that a new port can be installed. 
   Once the soluble seals have been repaired, the user can attach a pump to fitting  122  and repressurize lines  46 ,  126  and  128 . Thereafter the handle  16  ( FIG. 1 ) can be moved to the open position  42  in the manner previously described. (Alternatively, the handle  16  can be swung to the open position  42  before the lines are repressurized, also in the manner previously described.) 
   Referring now to  FIG. 12 , previously mentioned valve  10  is shown with its movable member  18  connected to previously mentioned valve handle  16 . A bracket  136  is clamped to one of the pipes connected to valve  10  in a manner similar to that shown in  FIG. 1. A  pneumatic cylinder  138  is supported on bracket  136  with its piston rod  140  connected to beam  142 . Post  146  on beam  142  supports a catch  144 , which is shown bearing against an edge of valve handle  16  to hold it in the open position. 
   In a manner similar to that previously described, the release of pressure in line  46 A causes elements  140 ,  142  and  146  to move in the indicated direction. Consequently, catch  144  will move to position  148 , thereby releasing handle  16 . One of the spring biasing mechanisms disclosed previously can be used now to swing handle  16  to a closed position. 
   In some cases, the pressure in line  46 A may diminish over time due to minute leaks, chemical absorption of the air in the lines, stretching of components, etc. Although one can periodically repressurize the lines in the manner previously described, this embodiment employs an accumulator  150  connected by line  152  to one of the branches of T fitting  154 , whose other two branches connect to lines  46 A and  46 B. Accumulator  150  is a passive device offering a supply of air that maintains the pressure in the lines  46 A and  46 B. 
   Referring to  FIG. 13 , accumulator  150  is shown as a chamber containing an inflatable member  152  having a nipple  154  projecting through a wall of chamber  150 . Member  152  can be initially inflated, causing member  152  to stretch. This produces a pressure at nipple  154  as a consequence of air pressure on the inside and outside of member  152 , as well as the elasticity of member  152 . Therefore, if the system has a minute leak, member  152  can partially deflate supplying the missing air and maintaining a relatively constant pressure in the system. 
   An alternate accumulator shown in  FIG. 14  has a chamber  150 ′ with a nipple  150 A′. A piston  156  is slidably mounted inside chamber  150 ′ and is biased in a direction towards nipple  150 A′ by a compression spring  158 . As before, air lost from the system by minute leaks or other factors can be replaced as spring-biased piston  156  is driven towards nipple  150 A′ by spring  158 . Again, the accumulator  150 ′ maintains relatively constant pressure in the system. 
   Referring to  FIG. 15 , previously mentioned valve  10  is shown coupled between pipes  12  and  14  and controlled by operating handle  16 , as before. In a manner similar to that described in  FIG. 1  an extension spring  24  can bias handle  16  toward the closed position (transverse to pipes  12  and  14 ). 
   In this embodiment a pneumatic cylinder  161  is pivotally supported on pipe  12  by pipe clamp  159 . The cylinder&#39;s piston rod  161 A is pivotally connected to the distal end of handle  16 . When cylinder  161  is driven by pressure in line  163 , piston rod  161 A fully retracts and keeps handle  16  in the open position, parallel to pipes  12  and  14 . Should pressure be released in line  163  in the manner previously described, piston rod  161 A will be free to extend as spring  24  pulls handle  16  into the closed position transverse to pipes  12  and  14 . 
   Referring to  FIG. 16 , previously mentioned valve  10  is shown with its movable member  18  connected to previously mentioned valve handle  16 . The pipe  12  connected to valve  10  supports a bracket  160  by means of pipe clamp  162 , which is constructed in the same manner as the pipe clamps of  FIG. 1. A  pneumatic cylinder  164  is attached to bracket  160  with its piston rod  166  pivotally connected to one end of lever  168 , whose opposite end  170  acts as a catch that bears against an edge of handle  16  to hold it in the illustrated open position. Lever  168  is pivoted on a clamp  172  that is located between valve  10  and clamp  162 . 
   When pressure is released from line  46 ″ piston rod  166  retracts to rotate lever  168  clockwise until catch  170  is released from the edge of handle  16 , allowing a spring mechanism (not shown, but similar to those previously described) to drive handle  16  from the illustrated open position to a closed position. It will be appreciated that the pressure release may in some embodiments cause rod  166  to extend and rotate lever  168  counterclockwise to release handle  16 . 
   Referring to  FIG. 17 , previously mentioned valve  10  is shown with its movable member  18  connected to previously mentioned valve handle  16 . A bracket  172  is attached to a pipe associated with valve  10  in a manner similar to that previously described. One end of bellows  174  is mounted on bracket  172  and the other end is the attached to a platform  176  that supports catch  178  whose outer end engages the edge of valve handle  16 , keeping it in the illustrated open position. 
   When pressure is released from line  46 ′″ bellows  174  collapses in the indicated direction, thereby releasing catch  178  from valve handle  16 , allowing it to be driven to a closed position under the urging of a spring mechanism (not shown, but similar to the spring mechanisms previously illustrated). 
   Referring to  FIG. 18 , previously mentioned valve  10  is shown with its movable member  18  connected to previously mentioned valve handle  16 . A bracket  180  having an L-shaped cross-section is attached to a pipe associated with valve  10  in a manner similar to that previously described. Hinged to the distal edge of bracket  180  is an arm  182  whose distal end has a catch  184  engaging an edge of valve handle  16  and keeping it in the illustrated open position. Captured between bracket  180  and arm  182  is a bladder  186  that has a nipple (not shown) that connects to the previously mentioned pressure line (for example, pressure line  46  of FIG.  7 ). 
   When pressure is released from the pressure line, bladder  186  deflates and allows arm  182  to swing toward bracket  182 . Arm  182  may be driven in this direction by a torsion spring  188  located at the hinge between bracket  180  and arm  182 . The rotation of arm  182  will release catch  184  from handle  16  and allow it to swing to the closed position under the urging of a spring (not shown, but similar to the spring mechanisms previously illustrated). 
   Referring to  FIG. 19 , previously mentioned valve  10  is shown with its movable member  18  connected to previously mentioned valve handle  16 . A bracket  190  is attached to a pipe associated with valve  10  in a manner similar to that previously described. A cover  196  is threaded onto one end of vessel  192  whose other end has a nipple  194 . A diaphragm  198  is sealingly captured between cover  196  and vessel  192 . A post  200  attached to the center of diaphragm  198  projects through aligned holes in cover  196  and bracket  190 . The distal end of post  200  supports a catch  202  that engages the edge of handle  16  to hold it in the illustrated open position. 
   When pressure is released through the nipple  194 , diaphragm  198  is no longer distended and pulls post  200  inwardly, thereby releasing catch  202  from handle  16  and allowing it to swing to the closed position under the urging of a spring (not shown, but similar to the spring mechanisms previously illustrated). 
   It is appreciated that various modifications may be implemented with respect to the above described, preferred embodiments. While the foregoing contemplates protecting against leakage of water, other embodiments may have plugs that are soluble in other fluids in order to protect against spills and leakage of that other fluid. Instead of helical springs, other embodiments may obtain a yielding or elastic effect by employing elastic members, leaf springs, air compression devices, permanent magnets, etc. Also, in some embodiments a discrete spring will be unnecessary if the pneumatic cylinder or other pressure operated device has an internal return spring. The foregoing embodiments acted upon an elongated handle, but some embodiments may apply torque directly to the valve&#39;s movable member. Also, the foregoing apparatus can be adapted to valves that are controlled by a nonrotating member, such as a slide. Furthermore, in some embodiments components inside the valve body may bias the valve toward a closed position without the need for external biasing components. Likewise, pressure operated components may be placed inside the valve body in order to release the valve or drive the valve into a closed condition. Also for embodiments that require a higher degree of sensitivity, the soluble plug may react with the leaked fluid and quickly break down by a chemical reaction, effervescence, etc. Also, the catch mechanisms may be actuated through a variety of links or transmissions, such as gear trains, pulleys, chains, etc. Moreover, the pressure lines may contain any variety of compressed gases or other fluids, not just compressed air. Furthermore, the magnitude of the pressure under normal unreleased conditions can be much greater or much less than 5 psi. Moreover, some embodiments may employ a negative pressure (partial vacuum) that is released when a soluble plug dissolves (therefore, the term “pressure” as used herein refers to both positive and negative pressure). In addition, the size and shape of various components can be altered depending upon the desired strength, speed of operation, structural integrity, thermal stability, etc. 
   Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.