Abstract:
There is provided a system for detecting a leak in a piping system, including a monitoring unit disposed at a gateway of the piping system for indicating fluid flow, a gauging unit for gauging the duration of continuous fluid flow, and an indication unit for determining the existence of a leak based on the duration. A method for detecting a leak in a piping system is also provided.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates in general to piping systems of buildings and more particularly, to the detection of leaks in piping systems of buildings and to automatically shutting them off, when a leak is detected. The invention is further concerned with a method for detecting a leak in a piping system. 
       BACKGROUND OF THE INVENTION 
       [0002]    U.S. Pat. No. 6,317,051 is considered to be the closest prior art. It discloses a water flow monitoring system for determining the presence of leaks in piping having water flowing therethrough under high pressure. The system includes a flow monitor mounted on a pipe for sensing the flow of water through the pipe. There is also provided a controller, composed of a timer and/or an accumulated volume meter associated with the flow monitor, to determine when the flow has continued for a pre-selected period of time, and/or when the amount of water has exceeded a pre-selected accumulated volume threshold, and logic components responsive to changes in flow rate. Upon detection of flow for the pre-selected period of time, and/or pre-selected accumulated volume threshold, a valve is actuated to stop flow through the pipe. 
         [0003]    One of the problems that U.S. Pat. No. 6,317,051 deals with is how to indicate whether a water flow is “normal” or a leak in the piping system. According to this patent, a second monitor is provided close to the sewer to sense whether the flow of water has continued through the piping system to the sewer. If the flow is sensed at both locations, then it is assumed that there is no leak. If, however, the flow continues in the upstream location, but not near the sewer, this would be indicative of a leak in the system. 
       DISCLOSURE OF THE INVENTION 
       [0004]    It is an object of the present invention to provide a system and a method for detecting a leak in a piping system, which overcomes the drawbacks of the prior art. 
         [0005]    It is a further object of the present invention to provide a system and a method for detecting a leak in a piping system, based on gauging a duration of fluid flow. 
         [0006]    Other objects and advantages of the invention will become apparent as the description proceeds. 
       SUMMARY OF THE INVENTION 
       [0007]    In accordance with the present invention there is therefore provided a system for detecting a leak in a piping system, comprising a monitoring unit disposed at a gateway of said piping system for indicating fluid flow, a gauging unit for gauging the duration of continuous fluid flow, and an indication unit for determining the existence of a leak based on said duration. 
         [0008]    The invention further provides a method for detecting a leak in a piping system, comprising the steps of monitoring fluid flow through a gateway of said piping system, gauging a duration of said fluid flow, and determining the existence of a leak if said duration exceeds a predetermined time period. 
         [0009]    In one aspect, the present invention is directed to a system for detecting a leak in a piping system, the system comprising a monitoring unit disposed at a gateway of the piping system (whether it is an entry or an exit to the piping system), for indicating fluid flow, a gauging unit for gauging the duration of continuous fluid flow, and an indication unit for determining existence of a leak from the duration. 
         [0010]    The system may further comprise a spigot unit for stopping the flow of fluid through the gateway upon indicating a leak of fluid in the piping system. The spigot unit may comprise a valve operated by electric power. 
         [0011]    The system may further comprise an alarm unit for informing a user about the indication of a leak in the piping system. 
         [0012]    According to one embodiment of the present invention, the indication unit determines a leak upon indicating by the gauging unit a continuous flow during a time period. 
         [0013]    According to another embodiment of the invention, the indication unit determines a leak by charging a capacitor upon existence of flow in a pipe while continuously discharging the capacitor, until the charge of the capacitor reaches a certain threshold beyond which a leak is determined. The ratio of the discharging may be determined by a trimmer. 
         [0014]    According to one embodiment of the invention, the indicating fluid flow is carried out by monitoring a gauge of fluid flow of the piping system, e.g., by a LED operative for generating a light beam through the gauge, and a light indicator operative for detecting interference in the light beam, thereby indicating a movement of the gauge, thereby indicating flow. The indication unit may comprise a CPU. 
         [0015]    In another aspect, the present invention is directed to a method for detecting a leak in a piping system, the method comprising the step of monitoring fluid flow through a gateway of the piping (whether it is an entry or an exit to the piping system), gauging the duration of the fluid flow and determining the existence of a leak, if the duration exceeds a predetermined time period. The existence of a leak may be determined by indicating a continuous flow during a predetermined time period. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures so that it may be more fully understood. 
           [0017]    With specific reference now to the figures in detail, it is stressed that the particulars shown are by way of example and for purpose of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. 
           [0018]    In the drawings: 
           [0019]      FIG. 1  schematically illustrates a system for detecting leaks in a domestic piping system, according to a preferred embodiment of the present invention; 
           [0020]      FIG. 2  schematically illustrates a monitoring unit of a system for detecting leaks in a piping system, according to a preferred embodiment of the present invention; 
           [0021]      FIG. 3  schematically illustrates the monitoring unit of  FIG. 2 , wherein the cover is closed; 
           [0022]      FIG. 4  schematically illustrates a circuit for indicating continuous flow during a time period, according to a preferred embodiment of the present invention, and 
           [0023]      FIG. 5  schematically illustrates a spigot unit, according to a preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]      FIG. 1  schematically illustrates a system for detecting leaks in domestic water piping, according to a preferred embodiment of the present invention. The basic component of the system is a water flow-monitoring unit  2  for monitoring the flow of water through pipe  4 , for indicating a leak. According to a preferred embodiment of the present invention, the flow-monitoring unit  2  is mounted on a domestic water meter  6 , preferably on a cover  8  thereof. The monitoring unit  2  is detailed in  FIGS. 2 and 3 . 
         [0025]    The system may further comprise a spigot unit  10  for stopping water flow through pipe  4 , in the event of a leak. The spigot unit  10  comprises an electrical motor  12 , which is mounted on the tap or valve  14 . The spigot unit  10 , further detailed in  FIG. 5 , is activated to stop the water flow when a leak is indicated by the monitoring unit  10 . 
         [0026]    The system may further comprise an alarm unit  16  for informing a user about a leak. The alarm unit  16  comprises a transmitter  18 , which sends a signal to a domestic alarm system  20 , e.g., calling a user&#39;s mobile telephone, etc. The alarm unit  16  may include a rechargeable battery  22  and a dynamo  24 , which rotates as the water flows in pipe  4  and charges the battery  22 . Other power sources can be employed, such as domestic electric power. 
         [0027]    Assuming that pipe  4  is the water source to a building, i.e., the gateway of the piping system, it is preferable to mount a system for detecting leaks on this pipe  4 , passing from a wall of the building  26  to, e.g., a sink  28 , which is located inside the building  26 . 
         [0028]      FIG. 2  schematically illustrates the flow-monitoring unit  2  for detecting leaks in a piping system, according to a preferred embodiment of the present invention. According to this embodiment, the monitoring unit  2  is mounted on a water meter cover  8 . The cover is shown in its open state and in  FIG. 3  the cover is closed. The water meter  6  comprises a counter  30 , one or more gauges  32  and a further gauge  34 , in the form of a vane. 
         [0029]    The monitoring unit  2  includes a LED  36  and a light sensor  38 , such as a photoelectric cell.  FIG. 3  schematically illustrates the monitoring unit  6  of  FIG. 2 , wherein the cover  8  is closed, so that the LED  36  and sensor  38  are disposed above the gauge  34 . In order to indicate water flow through the water meter  6 , LED  36  lights the rotating element, namely, the gauge  34  of the water meter  2 , when the cover  8  is closed. The light produced by LED  36  is reflected and sensed by sensor  38 . 
         [0030]    In order to enable sensing an intermittent signal, at least one of the elements  36  or  38  has to be limited to a “small” region comparable to the entire region of the gauge  34 , and to produce a narrow light beam (comparable to the size of the gauge  34 ), or alternatively, the sensor  38  has to sense a “small” region (comparable to the size of the gauge  34 ). For example, if the lighted and/or sensed region is 20% of the diameter of the gauge and it is located at the edge of the gauge, then an intermittent signal can be sensed, and also a spot of e.g., transmitted and reflected IR light provide an indication, if the rotation speed of the gauge is “high”. 
         [0031]    According to a preferred embodiment of the invention, indicating a leak in a piping system is carried out by analysing continuous flow during a time period. For example, in a domestic piping system, continuous water flow during a time period of four hours may not be reasonable. Thus, if the vane of gauge  34  has not moved for a period of four hours, it means that there is no leak. According to another example, in a domestic piping system it is expected that during a vacation, no water flow will be indicated. Therefore, in this situation, if a continuous flow is indicated, i.e., for about two minutes, it may indicate a leak. 
         [0032]    As explained above, in a domestic piping system, continuous water flow during a time period of, e.g., four hours, is not reasonable.  FIG. 4  schematically illustrates a circuit for indicating continuous flow during a time period, according to a preferred embodiment of the invention. While gauge  34  rotates, capacitor  40  is charged until it reaches a certain level, which activates another mechanism, such as an alarm unit  16 , a spigot unit  10 , etc. The signal sensed by sensor  38  is amplified by transistors  46 ,  48 , which results in charging capacitor  40  through resistors  50 ,  52 , while, on the other hand, the circuit discharges capacitor  40 . The discharging rate can be adjusted by trimmer  44 , whereby a user can control the time required for the capacitor  40  to reach the level at which the other mechanism will be activated. 
         [0033]    The circuit scheme of  FIG. 4  is an example demonstrating the simplicity of the circuitry required for implementing the present invention. Of course, more sophisticated circuitry can be employed, such as a computerized mechanism, for example, a CPU. 
         [0034]      FIG. 5  schematically illustrates a spigot unit  10 , according to a preferred embodiment of the invention. An electric motor  12  is connected to tap  14  by a clip  54 . The motor is fixed to the pipe  4  by a frame  56  and screws  58 . The power and polarity for rotating the tap  14  is provided by an external power source (not shown). 
         [0035]    Although nowadays there are a variety of electromechanical means on the market for opening and closing water flow through a pipe (e.g., a solenoid), the mechanism illustrated in  FIG. 5  is unique, due to the fact that it can be installed by any user, not necessarily a plumber. 
         [0036]    It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrated embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.