Abstract:
A pilot operated shutoff valve system with leak detector for automatically shutting off a water supply to appliances such as a clothes washing machine, dishwashing machine, sink, toilet, or refrigerator equipped with an ice maker, comprising a sealing member movable within said valve body between an open position wherein the sealing member does not block main fluid flow, and a closed position wherein the sealing member blocks main fluid flow.

Description:
FIELD OF INVENTION 
   This invention relates to a pilot operated valve system that will detect the presence of a water leakage and turn off the associated valve in order to stop the flow of the water, thus avoiding significant property damage. More particularly the invention pertains to such applications as clothes washing machines, dishwashing machines, toilets, sinks, and refrigerators equipped with ice cube makers, which occasionally are the source of water leaks due to broken hoses, faulty water level detectors, and the like. Insurance companies have recently disclosed that water damage claims have exceeded fire damage claims. This emphasizes the need for preventive measures as would be provided by this invention. Since the invention does not require any electronics circuitry or complex mechanical devices to function, it provides a cost-effective and reliable means of turning off the source of water leakage. 
   DESCRIPTION OF PRIOR ART 
   There are numerous water leak detection systems, most of which involve the use of an electronic means for sensing the presence of fluids such as water. The sensor elements of such systems typically involve measuring the conductivity of the water and use such a detection means to energize a solenoid or other such device to turn off an associated water valve. Not only does the electronics circuitry add cost and reduced reliability, but also requires the presence of electrical power to function. If a water leak occurs coincidentally with an electrical power outage, the valve will fail to accomplish its purpose, unless auxiliary power is supplied. 
   There are several prior art patents that provide water shutoff protection utilizing a water sensor that changes physical properties when placed in contact with water, thereby activating a valve shutoff device. Upon review it will become evident that most of these patents are intended for use on water heaters. Installation of such shutoff devices requires plumbing skills such as cutting into the existing water source pipe and soldering the new valve device in place or installing the necessary threaded fittings to accommodate the new valve. In many locations it would involve hiring a licensed plumber to comply with local building codes. The cost and complexity of such an installation often is a deterrent to undertaking the project. As will be seen by the following disclosure the proposed water shutoff system of the present invention is intended for use on the indicated appliances such as clothes washing machines, etc. and can be easily installed. Since no knowledge of plumbing skills is required, this invention would lend itself to do-it-yourself installation. 
   One device described in U.S. Pat. No. 2,798,503, dated Jul. 9, 1957, issued to Carver et al, utilizes a water softenable link that dissolves when coming in contact with water leaking from a water heater into an associated drip pan. As described, the cable attaching the water softenable link to the shutoff valve must be positioned directly beneath the shutoff valve so that the softenable link can be anchored in the drip pan. While appropriate for this installation it would not provide the flexibility to be applicable on other applications. 
   Another device described in U.S. Pat. No. 3,920,031, dated Nov. 18, 1975, issued to Maxfield provides a water shutoff device associated with a water heater application. The water detection means involves the use of a water-soluble material held in compression by a spring. The water detection means is placed in a drip pan that surrounds base of the water heater such that, as water leaks from the faulty water heater, it will reach a level to dissolve the detection means which in turn releases a spring driven valve that is plumbed into the water supply line of the water heater. 
   There are numerous patents that describe the application of the pilot valve technology. One of the more prominent patents is U.S. Pat. No. 4,387,878 dated Jun. 14, 1983 and issued to Zuksusky. This patent describes the use of a flexible diaphragm, in conjunction with specifically sized apertures, to control the open or closed valve condition. The Zuksusky patent utilizes an electric solenoid to open or close the appropriate pilot aperture, thereby allowing fluid to flow or not flow through the valve assembly. The present invention utilizes a modification of the pilot valve configuration, without the solenoid requirement, and will be described in detail later. 
   U.S. Pat. No. 5,169,117 dated Dec. 8, 1992, issued to Huang shows applicable prior art to be cited in this application. This patent describes a means for opening and closing a pilot valve by moving magnets in such a manner to open or close the pilot aperture. The magnet movement is accomplished using a small drive motor and hence requires the use of electric power as opposed to the present invention that requires no electric power to operate. 
   Another device described in U.S. Pat. No. 5,632,302, dated May 27, 1997, and issued to Robert M. Lenoir, Jr. provides two different means of specifically dealing with water heater leakage. One means involves the use of an electrical sensor to detect the presence of water leakage specifically from a water heater in order to activate a solenoid to turn off an associated water valve located in the cold water input pipe of the water heater. A second described means involves the use of a thin, dissolvable strip, which is in tension, and dissolves in the presence of water thus releasing a spring mechanism which, in turn, activates a spring loaded valve specifically located in the cold water input pipe of a water heater. There are two basic drawbacks to this second means as described. First, the use of a standard ball valve in such an application requires the use of a spring-loaded valve with a very strong spring. Ball valves typically involve full contact seals such as O-rings on both the inlet and outlet sides of the rotating ball. These O-rings produce a great deal of pressure on the ball, thus requiring inordinate rotational torque to close the valve, making the valve reliability questionable. Second, the dissolvable strip as described in the invention is shown in tension. Most such materials, which might be used as described, are composed of a water soluble, crystalline structure that exhibits poor tensile strength, thus making it unreliable and subject to premature failure. As will be seen later, the present invention overcomes the above shortcomings and provides an easily installed system for water and, where applicable, non-water systems. 
   Yet another U.S. Pat. No. 6,024,116, dated Feb. 15, 2000, issued to Almberg et al, again deals specifically with water leak detection in water heater applications. It provides a water softenable latch that, when exposed to water, will release a valve mechanism from its open to closed state thus turning off the water supply. In addition the invention turns off the gas supply to the water heater. 
   U.S. Pat. No. 6,792,967, dated Sep. 21, 2004, issued to Franklin, the inventor herein, describes a water shutoff valve with leak detector that is designed to function primarily with such applications as clothes washing machines, dishwashing machines, toilets, sinks, and refrigerators equipped with ice cube makers. Although the valve described in the U.S. Pat. No. 6,792,967 patent accomplishes the objectives as described, it has two shortcomings that might be considered objectionable in certain operating situations. The first such shortcoming occurs after the valve has been set to a closed position as a result of a water leak being detected. After the leak has been repaired the valve must be reset to an open position to allow normal fluid flow to the applicable appliance. It has been found that in some situations pressing the main body of the valve in an axial direction to reset it to an open position causes what is commonly called a hydraulic lock. This hydraulic lock occurs as a result of trying to compress a liquid. In this case the liquid would be the water trapped between the water source valve and the shutoff valve to be reset. The simple solution to this problem is to turn off the water source valve and momentarily unthread the coupling between the water source valve and the shutoff valve thus relieving the hydraulic lock. It is believed that this may present a problem for those individuals who are not mechanically inclined. A second shortcoming was found in my original patent, namely, that the water shutoff valve required an ability to elongate in an axial direction when activated to a closed position. Thus the valve was restricted to use with flexible water lines that coupled the output of the shutoff valve to the applicable appliance. In most applications this would not be a problem, however in toilet installations, for esthetic reasons, it is often desirable to use a rigid, chrome-plated pipe to couple the output of an associated water source valve to the toilet tank. Obviously the shutoff valve described in U.S. Pat. No. 6,792,967 would not allow use in such an application. It is the goal the present invention to overcome the above shortcomings and to describe a valve system that utilizes a variation on proven pilot valve technology, in conjunction with the technology described in my earlier patent, to produce a more acceptable shutoff valve with leak detection capabilities. 
   Most prior art that was found addresses the subject of water leak conditions as they pertain to water heaters. The following described invention pertains more specifically for use with clothes washing machines, dishwashing machines, toilets, sinks, and refrigerators equipped with ice cube makers. 
   SUMMARY OF THE INVENTION 
   This invention provides a simple, reliable means of detecting and shutting off the source of most common water leaks involved with clothes washers, dishwashers, toilets, sinks, and refrigerators equipped with ice cube makers by utilizing a pilot operated shutoff valve in conjunction with a water sensor. Although the following invention description focuses primarily on those appliance applications listed above, which involve water leakage, it could likewise apply to other applications involving the use of other non-water fluids, where applicable. As will be seen later, the valve described in this invention utilizes a flexible diaphragm that allows water to flow from the valve&#39;s entry port to its exit port in normal operation but closes the water flow path when activated to its closed condition. The use of this pilot valve structure, in conjunction with a water sensor and activation mechanism, provides a compact, simple water shutoff device. The use of this valve does not preclude the use of other pilot valve configurations by those skilled in the art to accomplish the goals of this invention. 
   The water sensor described in this invention utilizes a water-soluble substance in a compression mode. Other methods for containing the water-soluble material, for example, in a bending, torsion, or tension mode, as devised by those skilled in the art, should not detract from the spirit of this invention. The water-soluble substance could be composed of such materials as sugar, salt, or the like. These materials exhibit relatively high strength in compression when dry and lose most if not all of that strength when exposed to a fluid such as water. As will be shown later with regard this invention, a spring maintains pressure against the water-soluble substance and will initiate a closure of the associated valve when the water-soluble substance dissolves. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a typical clothes washing machine installation with water sensors and shutoff valves located at the inlets to the hose lines. 
       FIG. 1A  shows an enlargement of an area of  FIG. 1  to provide a more detailed depiction of the shutoff valve installation. 
       FIG. 2  shows a typical toilet installation with a water sensor and shutoff valve located at the inlet to the rigid pipe that passes water to the toilet reservoir tank. The rigid pipe can be replaced by an appropriate flexible hose. 
       FIG. 3  shows a partial cutaway of a typical sink installation with a water sensor and shutoff valve located at the inlet to the flexible hose line. 
       FIG. 4  shows a partial cutaway of a typical refrigerator installation equipped with an automatic ice maker device, along with a water sensor and shutoff valve connected to a water source via a hose or tubing means. 
       FIG. 5  shows the external side view of the shutoff valve used with hose connections on typical dishwashing machine or clothes washing machine installations. 
       FIG. 6  shows the external side view of the shutoff valve with typical fittings for toilet, refrigerators equipped with ice makers, and sink installations. 
       FIG. 7  shows an external front view of the shutoff valve with typical fittings for toilet, refrigerators equipped with ice makers, and sink installations. 
       FIG. 8  shows a cross-sectional side view of the shutoff valve with an input adapter for use with a standard compression fitting arrangement and a typical, threaded output for use with a flexible hose or rigid tubing connection. The valve is shown in an open condition. 
       FIG. 9  shows a cross-sectional end view of the shutoff valve with the outlet pilot aperture in an open condition which allows fluid to flow through the valve. 
       FIG. 10  shows the same cross-sectional side view of the shutoff valve shown in  FIG. 8  but with the valve in a closed condition. 
       FIG. 11  shows the same cross-sectional end view of the shutoff valve of  FIG. 9  with the outlet pilot aperture shown in a closed condition. 
       FIG. 12  shows an internal view of the valve latch mechanism when the valve is in an open condition. 
       FIG. 13  shows an internal view of the valve latch mechanism when the valve is in a closed condition. 
       FIG. 14  shows an external, top view of the water sensor assembly. 
       FIG. 14A  shows a partial isometric view of the water sensor cartridge. 
       FIG. 15  shows an external, side-elevation view of the water sensor assembly. 
       FIG. 16  shows a top, cutaway view of the water sensor assembly in a standby state. 
       FIG. 17  shows the top, cutaway view of the water sensor assembly in an activated state. 
   

   DETAILED DESCRIPTION 
   The following  FIGS. 1 ,  1 A,  2 ,  3 , and  4  are provided to show typical installations in which the water shutoff valve of the present invention might be utilized.  FIG. 1  shows a clothes washing machine  20  as it might be installed with its hot and cold water connections. Valves  21  and  21   a  represent the hot and cold water valves respectively, normally found on such appliance installations, providing the supply water to the clothes washing machine  20 . Attached to these valves  21  and  21   a  are the shutoff valves  22  and  22   a  to be described herein. Hoses  23  and  23   a  provide the water connections between the shutoff valves and the hot and cold water inputs to the clothes washing machine. Cable assemblies  24  and  24   a  are used to couple the water sensor assemblies  25  and  25   a  to the shutoff valves  22  and  22   a  respectively.  FIG. 1A  is an enlargement of the above mentioned valve  21 , shutoff valve  22 , cable assembly  24  and hose  23 , and is provided to visually clarify the actual connections. A typical connection that might be used in a dish washer application is not shown since it closely resembles that used on the clothes washing machine with the exception that only one hose connection, namely the hot water line, is used. 
     FIG. 2  shows a toilet installation  26  with its reservoir tank  27 . A typical installation has a valve  28  that allows a means for turning on and off the source of water necessary for operation. Connected to the top outlet of valve  28  is shutoff valve  29 . Although the internal structure of valve  29  is the same as the previously mentioned shutoff valves  22  and  22   a , it differs in the fact that the hose connections of valves  22  and  22   a  are replaced by smaller, threaded connections appropriate for that installation. Rigid pipe  30  provides the necessary coupling between the top of shutoff valve  29  and the bottom of the reservoir  27 . It should be understood rigid pipe  30  could be replaced by a flexible hose. Cable assembly  24  provides the necessary coupling between the shutoff valve  29  and the water sensor assembly  25 . 
     FIG. 3  shows a partial cutaway view of a typical sink installation in which a sink  31  is mounted in a cabinet  32  with the associated hot and cold faucets  33 . Although the side view shows only one faucet connection, it should be understood that the other faucet connection, either hot or cold, is identical to that shown in the foreground. Valve  28 , shutoff valve  29 , cable assembly  24 , and water sensor assembly  25 , are identical to that previously described in  FIG. 2  and, hence, carry the same number designations. Hose  34  provides the necessary coupling between the top of the shutoff valve  29  and the faucet configuration  33 . 
     FIG. 4  shows a typical refrigerator  35  installation with a partial cutaway view of the ice cube maker  36  as it might be located within the freezer compartment. The tubing  37  connects the ice cube maker to the shutoff valve  29  that is in turn connected to the water valve  28 . Cable assembly  24  connects the shutoff valve to the water sensor  25 . 
     FIG. 5  shows the outside structure of the shutoff valve  22  shown in  FIGS. 1 and 1   a . Coupling sleeve  38  is internally threaded, and independently rotatable as might be found on a standard water hose. It provides a means of fastening the shutoff valve to a standard water faucet or water pipe equipped with a hose thread. Cable assembly  24 , with its internal cable  90  and tubing  91 , is used to couple the shutoff valve to the associated water sensor assembly, to be described in detail later. Threaded outlet  39  for the shutoff valve  22  provides a means for connecting a hose to the shutoff valve. Such a hose is described in  FIG. 1  as items  23  and  23   a.    
     FIG. 6  shows the outside structure of the shutoff valve  29  shown in  FIGS. 2 through 4 . As previously mentioned, the only difference between this shutoff valve  29  and that of shutoff valves  22  and  22   a  is the inlet and outlet connection means. A small, internally threaded and rotatable sleeve  41  provides a means of connecting the shutoff valve  29  to a water source often using a compression fitting or rubber grommet, not shown. The standard installation would typically attach the inlet of the shutoff valve  29  to the threaded outlet of a valve  28 . Threaded outlet  42  provides a means of attaching the flexible hose  34  to the appropriate appliances as shown in  FIGS. 3 and 4  or to the rigid pipe  30  in  FIG. 2 . In both  FIGS. 5 and 6  item  40  represents the latching mechanism used to determine whether the shutoff valve is to be in an open or closed condition. 
     FIG. 7  shows the front view of shutoff valve  29  and displays the reset button  43 . This reset button is normally depressed and latched in that position when the shutoff valve  29  is open, allowing fluid flow through the valve body. If a water leak is detected and the shutoff valve is placed in a valve-closed condition the reset button  43  will extend outward from the valve body. This will provide an indication that the shutoff valve has been tripped to a closed position and, in addition, provide a means of resetting the valve to an open condition once the water leak has been repaired. 
     FIG. 8  is a cross sectional view of shutoff valve  29  shown in a valve open condition in which fluid is flowing through the shutoff valve. From this point on, for simplification, the word valve will be equivalent to shutoff valve unless stated otherwise. The fluid path is from left to right as shown by the flow arrow. Fluid enters the valve  29  at the input adapter  44  that is threaded into the valve body  45 . The threaded coupling  41  of  FIGS. 6 and 7  is not shown, but if shown would appear over the input adapter  44 . The input adapter  44  allows different size tubing to be installed depending on the size of the valve  28  output ( FIGS. 1 through 4 ) to which the valve  29  is to be coupled. There are two paths for fluid flow through the valve  29 , namely, the main fluid flow and the restricted fluid flow. The main flow represents the majority of fluid that flows through the valve  29 . The restricted flow is a small portion of the total fluid flow through the valve  29  and has a primary purpose of controlling the opening and closing of the main flow using the pilot apertures to be described. As shown, the main fluid flow is up and over valve seat  46 , downward between the valve seat  46  and alignment probe  47  portion of insert  48 , and through valve output  59 . In addition there is a restricted fluid flow through filter holes  49 , that are part of the diaphragm  50 , and then into reservoir  67 . Channel  51  of insert  48  provides a common flow path that couples all the filter holes  49 , allowing them to have a fluid connection to the input pilot aperture  52 . Next, the restricted fluid flow passes through an input pilot aperture  52 , through hole  53 , channel  54 , hole  55 , then past the clearance between the valve body  45  and magnet  56  enclosure  80 , and finally through an output pilot aperture  57  of insert  58  to the valve output  59 . The above flow path comprises the fundamental part of a pilot valve that allows it to function as it does. Although the pilot valve technology is well known in the art and accomplished using variations on a basic theme, the fundamental principle involves controlling pressure differentials to open or close the diaphragm  50  portion of valve  29 . Returning to the valve  29  of  FIG. 8 , the diaphragm  50  is normally composed of a rubber material that flexes at point  60  allowing it to move upward as shown or to move downward to close against the valve seat  46  as shown in  FIG. 10 . The periphery of diaphragm  50  is captured between the valve body  45  and the insert  61  at point  62 . The key element in determining whether the diaphragm opens or closes against the valve seat  46  is whether outlet pilot aperture  57  is open or closed by magnet  56  moving downward to place the seal element  63  against outlet pilot aperture  57 . This situation will be discussed in detail later. As shown in  FIG. 8  the restricted fluid passes through the open outlet pilot aperture  57  to join the main fluid flow. The aperture openings  52  and  57  are sized such that the input pilot aperture  52  is smaller than the output pilot aperture  57 . Because of this, a pressure differential is established between the lower side of diaphragm  50   a  and the reservoir  67 , since more fluid can escape via output pilot aperture  57  than can be supplied via input pilot aperture  52 . In normal operation the diaphragm  50  and insert  48  will move up and down as water demand is varied at the valve output  59 . This water demand will depend on the appliance valve, such as a sink faucet, being on or off. As long as outlet pilot aperture  57  remains open diaphragm  50  will flex upward each time an appliance valve is opened, thus allowing fluid passage through the valve  29 . It will be noted that O-ring  65  provides a fluid seal between valve body  45  and insert  61 . Likewise, O-ring  68  provides a fluid seal between valve body  45  and plug  69 . Spring  70  provides a small force to aid in the closure of diaphragm  50  against valve seat  46 . Plate  71  is held in place by screws  72  and functions to retain insert  61  and plug  69 . Alignment probe  47  functions to ensure that the surface of diaphragm  50  is in proper alignment with the valve seat  46  during closure. 
     FIG. 9  shows a cross sectional end view of valve  29  in the same relative vertical position as shown in  FIG. 8 . Magnet  56  and seal  63  are again shown in the upward position allowing fluid to flow through outlet pilot aperture  57 . The magnet  56  and seal  63  are encased in the enclosure  80  which has an opening  64  that allows the seal  63  to contact the tip of outlet pilot aperture  57  when magnet  56  is moved to its lower position. Magnets  78  and  79  are shown encased in the extensions  74  and  75  respectively of the reset button  43  forming a reset structure. Springs  76  and  77  provide a downward force against the magnets and thus against the reset extensions  74  and  75 . The reset button  43  and its extensions are locked in the position shown by pin  83  that is captured by latch arm  84 . Latch arm  84  is part of the latching mechanism  40  that will be explained in detail later. As shown, the polarity of magnets  78  and  79  are opposite to the polarity of magnet  56 . This arrangement allows the magnet fields of the three magnets to interact so as to cause magnet  56  to follow the position of magnets  78  and  79 . It would be possible to eliminate one magnet, say  78 , and still have the relative movement between magnets  56  and  79 . It was found, however, that by providing a second magnet  78  the reliability of the system was enhanced, largely because of the reduced friction of magnet  56  and its enclosure  80  rubbing against the adjacent wall in which they move up and down. Essentially magnet  56  could be considered as floating between the two outside magnets  78  and  79 . In addition, because the magnets  78  and  79  are encased in reset button  43  extensions  74  and  75 , the attractive force that would normally pull these magnets toward magnet  56  is restricted by the rigidity of the extensions. In this way the friction between the total reset button structure and the walls of the valve body is minimized. As will be seen later this lower friction reduces the force necessary to activate the latching mechanism  40 . 
     FIG. 10  shows a side, cross sectional view of the valve  29  in a closed condition. Fluid flow through the valve is now blocked by diaphragm  50  and insert  48  pressing against the valve seat  46 . The force necessary to hold these elements against the valve seat is a result of magnet  56  and its associated seal  63  closing the fluid flow path through output pilot aperture  57 . Since the pressure at the output  59  of valve  29  is lower than the input fluid pressure to the valve, the fluid that flows into the reservoir  67  via filter holes  49  and aperture  52  will cause an increase in pressure against the top of insert  48 , thereby pressing the diaphragm  50  firmly against the valve seat  46 . 
     FIG. 11  is once again a cross sectional, end view of valve  29  showing the position of magnet  56  and seal  63  now pressing against the output pilot aperture  57  thereby closing it to fluid flow. In this view it is assumed that a water leak has been detected by the detection means to be described later. As a result the latch arm  84  of latching mechanism  40  releases pin  83 , causing the reset extensions  74  and  75 , and the reset button  43  to move downward. Springs  76  and  77  produce the force necessary to cause this movement. Plate  73  provides a stop that limits the movement of reset button  43 . Since magnets  78  and  79  are now also positioned lower, their magnetic fields cause magnet  56 , seal  63 , and enclosure  80  to follow the downward movement. Thus it can be seen that by moving the reset structure up or down, magnets  78  and  79  will likewise move in a manner causing magnet  56 , seal  63 , and enclosure  80  to follow, thereby opening or closing the output pilot aperture  57 . This in turn, through the pilot valve action, causes valve  29  to open or close the fluid communication between its input and output. Although the opening and closing of the output pilot aperture  57  could be accomplished by means other than a magnetic arrangement, it would require a shaft with an O-ring seal that could provide a path for subsequent water leakage. 
     FIG. 12  is a top view of latching mechanism  40  with the top cover removed. Latch pin  83  has a force from springs  76  and  77  (FIG&#39;S.  9  and  11 ) acting to try to move it to the left. Latch arm  84  holds latch pin  83  in place. Latch arm  84  pivots about pin  85  and is biased in a clockwise direction by a torsion wire spring  86 . Cable assembly  24  includes an internal cable  90  that passes through slot  89  and has a retainer ring  93  fastened to the end of internal cable  90  allowing the retainer ring  93  to apply a rotational force on latch arm  84  when internal cable  90  is pulled upward. Lock ring  92  holds the cable tubing  91  from moving axially relative to the latch mechanism yet allows one to rotate relative to the other. As shown, the latching mechanism  40  is in a standby condition with the valve  29  in an open condition. 
     FIG. 13  is again a top view of latching mechanism  40  but with the latch mechanism shown in a tripped condition, as would be the case when a water leak has been detected. As will be explained later, when the leak detector senses a water leak condition internal cable  90  will be pulled within the cable tubing  91  causing retainer ring  93  to move toward the lock ring  92 . When this happens latch arm  84  is rotated in a counter clockwise direction, thereby releasing latch pin  83  to move to the left within slot  87 . As previously described, this releases the reset structure composed of items  43 ,  74 , and  75  to move in a manner that will cause closure of the outlet pilot aperture  57 , thereby causing the valve  29  to become closed to fluid flow. When the leak has been repaired, the leak detector can be reset by replacing the water sensor cartridge as will be described later. During the process of replacing the water sensor cartridge, the internal cable  90  will be forced to move within the cable tubing  91  allowing the latch arm  84  to rotate clockwise, back to its original position with the right most portion of latch arm  84  resting against ledge  88 . When the reset button  43  is pressed, the latch pin  83  will slide within slot  87  and will rotate latch arm  84  slightly in a counter clockwise direction as it moves up the incline portion  84   a  of latch arm  84  until the latch pin  83  reaches a point where the latch pin  83  will be recaptured by latch arm  84  and latched in place. It should be noted that, although not shown, the latching mechanism  40  can be installed on valve  29  in the position shown or flipped over to allow the cable assembly  24  to be routed in the opposite direction. There is a comparable slot opposite slot  87  that allows latch pin  83  to enter the latching mechanism  40  housing. The purpose in providing this feature is to allow more convenient routing of the cable assembly  24  depending on whether the latching structure is installed in a water hose application, i.e. clothes washing machine, or an alternate application such as under a sink or toilet. 
     FIG. 14  is the top view of the water sensor assembly  25 . The upper section  94 , along with the lower section  95  as viewed in  FIG. 15 , form the main enclosure of the water sensor assembly  25 . This main enclosure is connected to the water sensor cartridge  98  by a twist-lock coupling.  FIG. 14A  shows a partial isometric view of the water sensor cartridge  98  as would be seen at the interface  100  as indicated in  FIG. 14  between the upper section  94  of water sensor assembly  25  and the water sensor cartridge  98 . Locking segments  96  and  96   a  will interlock with comparable segments (not shown) that are part of the upper and lower sections  94  and  95  of water sensor assembly  25 . The lines  97  and  97   a  denote the inner surfaces of the cartridge  98  that interlock with the corresponding locking surfaces (not shown) of the upper and lower sections  94  and  95 . This interlocking configuration can be better seen in  FIG. 15  where segments  96  and  99  are shown mating at surface  97 . Thus it can be seen that replacement of the water sensor cartridge  98  is simply a matter of twisting and removing the water sensor cartridge  98  relative to the upper and lower sections  94  and  95  of water sensor assembly  25 . A replacement cartridge can be installed by reversing the process. With regard to the water sensor cartridge  98 , holes  101  allow fluid access to a water-soluble element  108  ( FIG. 16 ) contained within the sensor cartridge  98 . Item  102  is an end cap that captures the water-soluble element within the sensor cartridge  98 . Cable assembly  24  is routed to the latching mechanism  40  as previously described. 
     FIG. 15  is a side-view of the upper  94  and lower  95  sections of the leak detector assembly  25 . These sections are fastened together as an integral assembly. As previously mentioned, this view more clearly shows how the interlocking surfaces provide a means to couple the water sensor cartridge  98  to the upper and lower sections  94  and  95  of the water sensor assembly  25 . 
     FIG. 16  is a top, cutaway view of the water sensor assembly  25 . The internal cable  90  and tubing  91  enter the water sensor assembly  25  at the left end. Tubing  91  is held in axial position relative to the water sensor assembly  25  by lock ring  104 . Retainer ring  105  is fastened to the end of internal cable  90  and is located within a cavity  106  of plunger  107 . As shown, spring  110  exerts a rightward force against plunger  107 . The right end  107   a  of plunger  107  presses against plate  109  that acts to more evenly distribute the existing force against the water-soluble element  108 . Since the water-soluble element  108  has considerable strength in compression the plunger  107  will be held in the position shown. 
     FIG. 17  is a cutaway view of the water sensor assembly  25  after a water leak has been detected. When the water-soluble element  108  was exposed to water, or other appropriate fluid, it dissolves allowing spring  110  to force plunger  107  and plate  109  in a rightward direction. In doing so, retainer ring  105  that is fastened to internal cable  90 , exerts a rightward force on internal cable  90 , thereby causing it to move within the cable tubing  91 . This movement causes the latch mechanism  40 , previously described, to trip the valve  29  to a closed condition. Once the source of the water leak is repaired and any water leakage removed, the water sensor assembly  25  can be restored to a normal status by simply twisting and withdrawing the water sensor cartridge  98  to remove it from the upper and lower sections of the water sensor assembly  25 . A new cartridge can be installed by reversing the procedure. Of course it is also possible to make provisions for the water-soluble element  108  to be replaced within the cartridge  98  without having a removable cartridge. 
   One of the primary advantages of the described invention relative to the prior art is the ease with which it can be installed without disrupting the existing water supply lines or the water connections to the applicable appliances. When installing the described shutoff valve and sensor to the water sources for a clothes washing machine, the first step is to turn off the faucets or valves  21  and  21   a  controlling the hot and cold water to the clothes washing machine as viewed in  FIG. 1 . Next, the washing machine hoses  23  and  23   a  are disconnected from the hot and cold water faucets or valves  21  and  21   a . One of the described is shutoff valves  22  is now threaded onto the hot water faucet and another shutoff valve  22   a  is threaded onto the cold water faucet. Then the previously removed washing machine hoses  23  and  23   a  are threaded onto the threaded outlets of the hot and cold shutoff valves  22  and  22   a  respectively. The sensor assemblies  25  and  25   a  would now be placed on the floor adjacent to the washing machine or in a location that would optimize the possibility of detecting any future water leakage. Once the water source faucets or valves  21  and  21   a  are opened to allow flow to the washing machine the installation is complete. 
   In summary, the foregoing disclosure describes a pilot operated valve system having a water sensor assembly and an activation mechanism, which provides a means to turn off a water supply when a water leak is detected. This disclosure focuses primarily on specific applications such as clothes washing machines, dishwashing machines, toilets, sinks, and refrigerators equipped with ice cube makers, but could apply to appropriate, non-water, fluid-handling applications. Because of its design this valve system requires no electrical power to function. It should be understood, however, that anyone skilled in the art might provide a switching means to detect when the valve has been shut off, and utilize the switching means to activate an audible or visual alarm. Likewise, the water sensor and associated activation cable could be replaced by an electrical solenoid, controlled by a separate electronic water sensing and control system. In addition, it should be understood that the above valve description should not preclude the incorporation of the valve shutoff system as an integral part of the manual shut off valves which have been designated by items  21 ,  21   a , and  28  in  FIGS. 1 through 4 . In addition it should be noted that the pilot valve design, described herein, avoids many of the shortcomings associated with previous designs. Two such shortcomings are the previously described hydraulic lock condition that can exist, and the requirement that the valve be used in conjunction with flexible hose coupling only. This was due to the fact that the prior art valve had to physically elongate upon activation, thus precluding the use of rigid tubing to couple the valve to any external appliances. Although a particular pilot valve design has been used in the description of this invention, it should be understood that other pilot valve configurations could be used without departing from the spirit of this invention. The description of this invention is illustrative and not limiting; further modifications will be apparent to one skilled in the art, in the light of this disclosure and the appended claims.