Abstract:
An adjustable timing system controlled by a water meter indicator activates an electric shut-off valve at a main water supply to a building or apartment unit if a continuous flow of water exceeds the time setting. The timing system may optionally be set to a full open condition bypassing the timing function and allowing unrestricted water flow or an off condition preventing any water flow. The timing system is reset to begin anew timing the continuous flow of water each time that flow ceases and may be manually reset after a continuous flow of water has exceeded the time setting or a power interruption has disabled the water flow.

Description:
The present invention relates to fluid supply systems, especially residential or commercial water supply system&#39;s and more particularly to a water flow control system operable in response to continuous flow for more than a predetermined time to shut off the water supply thereby terminating flow after the predetermined time. 
     BACKGROUND OF THE INVENTION 
     It is desirable to prevent the excessive flow of water and resultant damage in a home, apartment or business in case of a leakage, freezing or vandalism or electrical outage. Excess water flow may occur from a number of other causes. For example, a leaking toilet valve, while not causing damage, may allow water to flow for an extended period of time resulting in an excessive water bill. It has been suggested to accomplish this by measuring water flow and turning the system off after a predetermined volume of water has flowed. Such an approach is slow to react to modest leakage and major damage may have already occurred by the time the system reacts. It has also been suggested to prevent excessive flow and damage by monitoring a water pressure differential and disabling the flow if this differential becomes too great. This technique works well for catastrophic leaks, but has the disadvantage of never detecting minor leaks that can cause great damage over a period of time. 
     SUMMARY OF THE INVENTION 
     The present invention provides a technique for minimizing damage due to water leaks in residential, business or other buildings. 
     The invention comprises, in one form thereof, a water supply system and process of operating the system to avoid excess inadvertent water loss as might be caused, for example, by leaks, a plumbing fixture malfunction, vandalism or interruption of electricity to a heating system of more than a predetermined time period. Water flow is monitored and the flow disabled if the monitoring indicates the detected flow has continued uninterrupted for a predetermined time interval. Flow interruption is achieved by removing electrical drive from a normally closed solenoid operated water valve. The system is reset or initialized to await a subsequent detection of water flow if the detected flow ceases prior to expiration of the predetermined time interval. The system operates substantially independent of the volume of water flow. 
     An advantage of the present invention is that the water system is shut off in response to detected water flow exceeding a predetermined time rather than depending on less leak indicative pressure changes or total flow measurements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fluid flow detecting system according to the present invention in one form; 
     FIG. 2 is a schematic illustration of the electrical portion of the system of FIG. 1; 
     FIG. 3 is a more detailed schematic illustration of the timer circuit of FIG. 2; and 
     FIG. 4 is a flow chart illustrating the fluid supply operating process of the present invention. 
     Corresponding reference characters indicate like or similar parts throughout the several drawing views. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings and particularly to FIG. 1, there is shown a water flow control system designed to avoid excess inadvertent fluid loss. The system includes a water flow detecting and signal generating device  13  for detecting a flow of water from inlet conduit  11  into intermediate conduit  15  and ultimately to a water utilization system such as a residence, apartment complex or business as illustrated by conduit  19 . The device  13  may, for example, be a water meter as shown in FIG.  1 . The device  13  functions as a fluid flow indicative signal source and monitors the system to detect a flow of water or other fluid by issuing fluid flow indicative-signals on line  23  so long as a fluid flow is detected. There is a normally closed solenoid valve  17  in circuit between conduits  15  and  19  which allows full water flow so long as its solenoid is energized, but closes upon loss of solenoid drive current. This valve may, for example, be an open frame, general-purpose solenoid valve such as the ASCO Red Hat II series 8003G or 8292G, or other suitable fluid valve. Under normal water usage conditions, the solenoid is maintained energized by a signal on line  25  from a timing and control unit  21  shown in greater detail in FIG.  2 . When switch  27  is in the Atimer≅ position, operation of a timing circuit to measure a predetermined time interval is initiated in response to an initial fluid flow indicative signal on line  23 . Upon expiration of the predetermined time interval, the fluid supply system is disabled by removing drive from line  25  closing the solenoid valve  17  and stopping the flow of fluid. An alarm indication such as buzzer, alarm light or other suitable indicator  31  indicates the water supply has been disabled. Manual resetting of the system and resumption of water availability may be achieved by momentarily depressing reset button  29 . If the flow of water stops prior to expiration of the predetermined time interval, causing the cessation of fluid flow indicative signals on line  23  for a sufficient time, the time interval measurement is interrupted and reset or initialized to be reinitiated upon receipt of a new initial fluid flow indicative signal. Switch  27  may be moved to the Aon≅ position to selectively enable the system to continuously supply fluid for time periods in excess of the predetermined time interval. Movement of switch  27  to the Aoff≅ position manually interrupts a supply of electrical energy to the solenoid valve  17  and selectively overrides the system to prevent the flow of fluid independent of fluid flow detection. This position may be utilized, for example, during a vacation or other prolonged absence. Overriding of the normal functioning of the system also occurs upon inadvertent interruption of a supply of electrical energy for a predetermined period of time since interruption of the supply of electrical energy most often would also effect the operation of a heating system. If the heating system were disabled for an extended period of time, damage to a water system may not be immediately detected when electrical energy was again provided to the heating system so some positive action is required to activate the water system after a power interruption. 
     In FIG. 2, the primary winding of transformer  33  is connected to a plug which may be coupled to a conventional 120 volt outlet. The transformer secondary provides a lower operating voltage such as 24 volts for the circuit. Rectifier  35 , capacitor  39  and 9 volt Zener diode  37  provide a 9 volt direct current for certain of the solid state components such as timer  49 . Switch  27  is seen to be a double-pole, triple throw switch shown In a first or upper position in which the control system is disabled allowing unrestricted water flow because the solenoid  17  is directly grounded by the upper movable contact and maintains the water valve  53  open. This is the Aon≅ position of FIG.  1 . Switch  27  may be moved to an Aoff≅ position in which neither movable contact couples any of the circuit components and where the control system disables the solenoid actuated valve preventing water flow. In the Atimer≅ position, the lower movable contact of switch  27  connects terminal  43  to ground. This is the third switch position in which the control system is operable to interrupt water flow only upon detecting substantially uninterrupted flow for the predetermined time interval. 
     Solenoid  41  controls a double-pole, double-throw solenoid actuated relay having an upper pair of normally open contacts which are operable when the solenoid is energized and the contacts closed to supply enabling current to the solenoid actuated valve  17 . The contacts of the relay are illustrated in FIG. 2 in the de-energized (normal) position. The solenoid actuated relay also has a second lower pair of normally open contacts which are operable when the solenoid is enabled and the contacts closed to form part of a latching circuit to maintain the solenoid energized by current flow from the transformer  33  secondary, through the conducting solid state switch  52 , solenoid  141  coil, closed movable contact  45 , and by way of terminal  43  of switch  27  to the grounded side of the transformer secondary. While not shown, alarm  31  may, for example, be a light or audible alarm connected between the hot or upper end of transformer  33  secondary winding and the lower grounded side of the secondary by the upper normally closed contacts of the solenoid actuated relay. The upper normally open contacts of solenoid  41  selectively connect solenoid  17  to ground while the lower normally open contacts selectively connect the winding of solenoid  41  to ground. Of course, the relationship of the switch, relay contacts and solenoids may be reversed so that the switch and relay contacts control the hot side of the transformer secondary rather than the grounded side if desired. 
     The water flow detecting and signal generating device  13  may, as shown in FIG. 1 comprise a digital signal generating water meter or, as in FIG. 2, some other flow indicative signal source. In one specific embodiment, a Badger Meter model RTR which provided five to seven volt pulses having a test circle indication and an electronic resolution of one-tenth of the test circle was employed. This meter is similar to the one illustrated by U.S. Pat. 4,868,566. Other digital or analog metering techniques could be employed so long as a flow indicative signal is provided. Upon receipt, of the first pulse or other flow indicative signal, a first timing circuit illustrated as a counter  51  begins timing of a predetermined time interval. In one form, the predetermined time interval was selectively adjustable through a range up to a maximum of about one hour. If the counter  51  reaches a prescribed count indicative, of expiration of the predetermined time interval, solid state switch  52  opens removing drive to the solenoid valve  17  allowing the normally closed solenoid actuated valve to assume its closed position interrupting the flow of water. With digital flow indicative signals, a second timer  49  begins timing of another time interval after receipt of each pulse, but is restarted upon receipt of each subsequent pulse. Thus, so long as the water flow continues, timer  49  never completes its task. However, upon expiration of the other time interval indicating a prescribed period of time in which no flow was indicated, the count of counter  51  is reset to its initial value and will only commence counting again upon receipt of a new flow indicative signal from  13 . In this way, the second timer  49  resets the first timing device  51  to an initial state upon a lapse of time during which no signal is received from the generating device. Timer  49  may, in some cases, be dispensed with, for example, cessation of an analog flow indicative signal may be adequate to appropriately reset counter  51 . In one implementation, the second timer  49  lapse of time was selectively adjustable through a range of about one to five minutes. After flow indicative signals cease, the solid state switch  52  returns to a conducting state, however water availability does not resume because the contacts of the solenoid actuated relay are both in the illustrated de-energized position. To restore potential water flow, a normally open reset switch  29  which is in parallel with the second or lower pair of normally open relay contacts is depressed to re-energize and re-latch the solenoid actuated relay. The functions of counter  51  and solid state switch  52  may, for example, be provided by a CNT programmable multifunction digital time delay relay/counter such as model CNT-35-96. 
     Timer  49  may be implemented as shown in FIG.  3 . The integrated circuit forming the nucleus of timer  49  is a type  555 . The one to five minute time adjustment is achieved by a variable 500,000 ohm potentiometer which is in series with a 100,000 ohm resistor  59  and 500 Φfd. capacitor  61 . Capacitor  63  is 0.01 Φfd. while resistor  55  is 10,000 ohms. 
     System operation is summarized in FIG.  4 . The commencement of water flow  65  initiates signals  67  indicative thereof. Upon receipt of a flow indicative signal, timing begins as indicated at  69 . The flow indicative signal is monitored at  71  and if the signal continues to, indicate a flow, timing is continued as shown at  73 . If monitoring indicates the flow has ceased (by expiration of the time set on timer  49 , for example), the timer is reset as at  75 . If the elapsed time  81  reaches the predetermined time, flow is disabled as shown at  79 . The length of time water flow that is allowed without shutdown (the count which counter  51  must reach before switch  52  turns off) is adjustable as shown at  77 .