Abstract:
A water monitoring and control system adapted for residential and commercial use automatically shuts off the water supply after a predetermined period of time, whether the flow is intentional or unintentional, thereby preventing damage from leaks and other malfunctions. The system also gives an indication of all water flow ranging from normal usage to leakage of a few drops and large flow, as would typically occur due to a break in the plumbing system. The system is easily bypassed in the event of power outages. In terms of hardware, the main components of the system include a normally closed water shut-off valve, preferably solenoid-operated. A pressure-responsive switch senses changes in water pressure and sends a signal in the event of a pressure drop, and a timer is provided to start a timing cycle when there is a demand for water, either intentional or unintentional, and shut-off the flow after a predetermined period of time selected by the user. The system also preferably incorporates a water demand indicator used to visually indicate water usage in the system, again, whether it is intentional or unintentional.

Description:
REFERENCE TO RELATED APPLICATION 
     This application claims priority from U.S. provisional Patent Application Serial No. 60/283,569, filed Apr. 13, 2001, the entire contents of which being incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to plumbing systems and, in particular, to a water monitoring system that closes off the supply line and performs other functions in the event a flow occurs longer than a predetermined period of time. 
     BACKGROUND OF THE INVENTION 
     It is important to prevent water damage in plumbing systems, which are often caused by leaks that occur in the system. Particularly in the absence of occupants, if such leaks are not detected early enough extensive damage may occur. 
     There are a variety of water flow control systems which shut off automatically in the event of any leakage. But existing systems of this kind tend to be extremely complex, costly, and difficult to install. 
     Accordingly, there remains a need for a simple water monitoring and control system adapted for use with residential and commercial building water systems. Ideally such a system would provide notice of all water flow, both intentional and unintentional, and keeps unintentional flow to a minimum, thereby reducing damage to the structure supplied by the system. 
     SUMMARY OF THE INVENTION 
     This invention improves upon the existing art by providing a water monitoring and control system capable of protecting both homes and businesses. Among other operations, the system automatically shuts off the water supply after a predetermined period of time, whether the flow is intentional or unintentional, thereby preventing damage from leaks and other malfunctions. 
     The system also gives an indication of all water flow ranging from normal usage to leakage of a few drops and large flow, as would typically occur due to a break in the plumbing system. The system is easily bypassed in the event of power outages. 
     In terms of hardware, the main components of the system include a normally closed water shut-off valve, preferably solenoid-operated. A pressure-responsive switch senses changes in water pressure and sends a signal in the event of a pressure drop, and a timer is provided to start a timing cycle when there is a demand for water, either intentional or unintentional, and shut-off the flow after a predetermined period of time selected by the user. The system also preferably incorporates a water demand indicator used to visually indicate water usage in the system, again, whether it is intentional or unintentional. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic view of a water monitoring and control system embodying the invention showing the various components; 
     FIG. 2 is a perspective view of a solenoid valve forming one of the principal components of the monitoring system; 
     FIG. 3 is a drawing which shows a differential switch that may be used according to the invention across the primary supply shut-off valve; 
     FIG. 4 is a drawing which shows an information center associated with the invention; and 
     FIG. 5 is a schematic/block diagram indicating important electrical components associated with the timer, controller, reset and drive functions. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference is now made to the figures, wherein a water monitoring and control system embodying the invention is designated generally at  8 . It will be appreciated that while copious references are made herein to “water,” the system applicable to any type of liquid or fluid. 
     The principle components of the system  8  include a normally closed, solenoid-operated valve  10 , a pressure responsive switch  12 , a timer  14  and a water demand indicator  16 . The solenoid valve  10  and pressure switch  12  are installed in the water line  18  supplying water to buildings such as a residence, and are typically disposed between a main, manually operated valve  20  and a first point of water demand of the water plumbing system in the building, such as a valve indicated at  22 . 
     Typically, the solenoid-operated valve  10  is installed at the exterior of the building near the main shut off valve  20 . The pressure switch  12  and timer  14  are located in a control box designated in broken line at  24 . The control box  24  can be located adjacent to the solenoid valve  10 , or other location in the water line  18  before the point at which water is demanded for the first time in the system such as the water demand valve  22 . 
     A suitable normally closed valve  10  may be obtained from Irritrol Systems of Riverside, Calif. and is identified as model 100PT. The preferred valve  10  uses a solenoid  26  as shown in FIG. 2, operating on DC supply such as 24 volts to open the valve  10  to water flow. Provision is made for operation of the valve  10  either manually or electrically by means of solenoid. A manual control  27  is provided to open and set the downstream water pressure. 
     The pressure switch  12  employed in the system is available from Square D Company and is identified as pressure switch 9013FSG2. The pressure switch  12  employs a diaphragm arrangement to detect a reduction in water pressure and acts to close electric contacts that energize and completes an electrical circuit  28  which is connected to the solenoid of the main control valve  10 . A circuit  30  is connected to the timer  14  and the circuit  32  communicates with the water-demand indicator  16 . 
     The characteristics of the pressure switch  12  are such that its range of operation can be selected so that the switch opens when the water pressure attains a pre-selected pressure and closes when the pressure drops below the pre-selected amount. The switch acts in response to a diaphragm which upon a reduction of water pressure moves downwardly to allow the contacts of an electric switch to come in contact with each other and close the switch. 
     As an alternative to pressure switch  12  located on one side of the valve  10 , a differential pressure switch may be interconnected across the valve  10 , to address problems which might be caused by typical pressure fluctuations in the supply line. Such a differential pressure switch may be implemented in a number of ways, including the use of a magnetic read-switch arrangement, depicted in FIG.  3 . In such a case, the solenoid  121  is controlled by a reed switch  130  which opens and closes in response to the movement of a magnetic piston  132  slidably disposed in a branch passage  134  between the inlet  114  and outlet  116  of the main flow-control switch  10 . Movement of the piston  132  in response to a pressure differential deflects the reed switch  130  and closes contacts to actuate the system. The sensitivity of the reed switch  130  may be regulated in a preferred range such as 5-10 psi, more or less, by way of an adjusting screw  136 . 
     In the event of power failure, the valve  10  can be opened by a control plunger  140  which is pushed and turned 180 degrees to manually lift the solenoid core and open the valve  110 . The end of plunger  140  is provided with an offset prong  142  that engages a recess  144  in the solenoid core. When the power is restored, the solenoid moves to its top position and releases the prong  142  so that the plunger  140  returns to its original position. 
     The timer  14  employed in the present system is obtainable from Danaher Controls of Gurney, Ill. In an actual embodiment of the invention, the model used was Eagle Signal 702070-001, Series B856. The characteristics of the timer are such that on actuation when water pressure drops and valve  10  opens, the timer starts at 0 and continues for a pre-selected time interval. At the end of the pre-selected time, the timer switch causes the control valve  10  to close, thereby preventing further water flow until it is reset. This may be done manually or, if the water pressure returns to normal prior to the end of the pre-selected period of time, it is automatically reset. 
     The water demand indicator  16  can be in the form of a light connected to pressure switch  12  by way of circuit  36 . The indicator provides a visual signal anytime the pressure switch  12  drops below its predetermined selected value to indicate a water flow of any kind, intentional or unintentional. 
     Operation 
     Assuming a fully pressurized system, the solenoid valve  10  will be in a closed position, and the pressure switch  12  will be at full pressure. The water demand indicator will not be activated, and the timer will be reset to 0. 
     Upon a water demand, for example, by opening of the valve indicated at  22 , the pressure switch  12  will detect a drop in water pressure and its internal switch will activate circuits  28 ,  30  and  32 . This causes the solenoid actuated valve  10  to open to permit water flow, the timer  14  to be energized and start its preset time interval and the water demand indicator  16  to indicate water flow. 
     If the demand for water ends within the pre-selected time period, the water pressure will increase in the line  18 , and the pressure switch  12  will close the main valve  10 , causing the timer  14  to reset to 0. At the same time, the water demand indicator will deactivate. If, on the other hand, the water demand exceeds the preset, predetermined time span, the timer  14  will activate circuit  34  to the valve  10 , causing it to close and terminate water flow. This occurs whether or not the water demand is intentional or unintentional. As a consequence, the period of the timer should be set to accommodate the expected usual water usage of the system. For example, based upon the amount of time a person uses to take a shower or water the lawn, or the length of time required for an automatic clothes washer or dishwasher, a period of a half hour or thereabouts might be appropriate. 
     Since the timer switch  14  terminates the flow of water if a pressure drop remains at the end of the preset time period regardless of whether the water demand is intentional or unintentional, the switch must be manually reset if the demand was intentional. For this purpose, a remote timer reset control  44  can be located at one or more convenient locations within the building and each connected by way of a circuit  46  to timer  14 . If desired, the timer reset control  44  can be a wireless unit eliminating the need for the electric circuits  46 . Such wireless control switches are available from Heath Company and is identified as Heath Zenith Model SL-6150. One or more of such reset controls can be located in convenient locations throughout the building such as the bathroom, kitchen, laundry room, and so forth, in the event it is found necessary to extend the period of time of the timer  14  to accommodate such functions as showers or lawn sprinkling systems. 
     FIG. 4 is a drawing which shows an information center associated with a preferred embodiment of the invention, and FIG. 5 is a schematic/block diagram of the electronics associated with the timer, counter and reset functions. As shown in FIG. 4, the information center includes a plurality of indicators, including a green LED  402  which indicates that power is on, and an amber LED  404  which indicates the flow of water, either intention or unintentional. A third LED  406  is illuminated when button  412  is pressed to initiate a pre-timed override, in this case 1 hour, and an amber LED  408  illuminates when the system has shut the water off, requiring a manual reset which may be activated through button  410 . 
     As shown in FIG. 5, an single integrated circuit, in this case, the BS-2 controller which includes a PIC microprocessor by Microchip Company. The device has 16 I/O lines (P0-P16), which can be used as digital inputs or outputs, and is preprogrammed with a basic interpreter for ease of encoding. The inputs and outputs of the circuit are used a shown, with some going to the various switches, and others driving the indicator lamps. A wireless remote reset, and local reset button, feed into pin  22 , and reset the circuit. To assist with drive capabilities, an MPS222A transistor is used, making direct connection to a 5 volt supply from a transformer power supply to the differential switch through external connections A-D. The solenoid, making specific connection through points C and D, utilizes a 24 volt signal directly from the transformer power supply. 
     Even very small leaks in the water system will cause a drop in the water pressure to activate the pressure switch  12 . As soon as this occurs, valve  10  will open momentarily to instantly re-establish pressure in the system and the water demand indicator will be activated and immediately deactivated as the water pressure repeatedly drops and is re-established in the system. The short cycles cause a flashing of the water demand indicator  16  giving notice that there is an unintentional water flow or a leak so that inspection can be made for repair. If the leak is of a sufficient magnitude, such as a steady stream, the timer will become activated and continue through its cycle to close off valve  10  and stop all water flow. 
     If the leak is rather small, such as a few drops per second, the preferred embodiment of the system counts the time intervals from the closing of the switch to the next closing of the switch. For example, if the leak is such that it takes a few seconds, or less than minute, or thereabouts, to “bleed” down to the next switch closing, the system according to this embodiment will memorize the time interval associated with the system. If the leak remains constant, the time interval will be similar to the previously detected time interval. Assuming that each time interval is within a preset range of the previous one, such as a few seconds, or thereabouts, the system according to this embodiment will count the number of such intervals, and shut off the water, requiring the system be reset manually if the count of such intervals reaches a preset number, such as  30 , with the understanding that this number as well as the similarity between time intervals is fully adjustable according to the invention. 
     In the event of an electric power outage, valve  10  remains in its closed position to prevent water flow. The monitoring system can be bypassed manually by movement of the bypass lever  50  forming part of valve  10  to a bypass position indicated in broken line in FIG.  1 . This will permit water flow in the system. At the time the manual bypass valve  50  is moved to its bypass position to permit water flow, a switch in a circuit  52  seen in FIG. 1 to an audible alarm  54  is closed or the bypass position will reset to normal when power is restored (see FIG.  3 ). When electric power is restored, the audible alarm will be activated to indicate that the manual bypass valve  50  is open so that the manual bypass valve  50  can be reset to its original position to permit the system to function automatically. 
     In summary, a water monitoring system and automatic control for such systems has been described in which a normally closed solenoid operated valve is activated to its open position each time there is a demand for water, either intentional or unintentional. A timer is used to permit flow for periods necessary for usual water demand purposes and if such periods are exceeded, the valve automatically closes to shut off the water supply. This serves to prevent excessive damage in the event of a burst water pipe line. All water flow is indicated by a steady visual signal, and small leaks are made known by a flashing signal.