Abstract:
A water shut-off system incorporates a water shut-off valve utilizing a pair of adjacently disposed electrodes, a transmitter and a receiving means. The water shut-off valve is in the form of a ball valve. A timing logic causes current to flow to a valve driving motor as electric pulses. A cam means and the electric pulses allow control of current flow to the motor so that the ball valve stops moving upon completion of a ninety degree rotation;

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to the problem of monitoring water leakages occurring in commercial and household water systems. In a more specific aspect the invention pertains to apparatus for automatically cutting off the water supply upon the detection of a leak. 
     A problem of great concern is that of water damage to carpeting, flooring, walls and furniture due to water leakage resulting from faulty water heaters, defective plumbing fixtures, appliances such as washing machines and dishwashers, as well as damage resulting from such unforeseen disasters as earthquakes and fires. The seriousness of this problem is evidenced by large a volume of patents. 
     By way of example U.S. Pat. No. 5,240,022 discloses an automatic shut-off. U.S. Pat. No. 4,845,472 provides an apparatus which responds to the sensing of water leakage from a water line of a hot water system. U.S. Pat. No. 5,190,069 utilizes wires embedded in insulation tape carrying leak detecting liquid sensing elements. U.S. Pat. No. 5,229,750 utilizes a float and solenoid valve combination to control a cut-off in the event of a water leak. U.S. Pat. No. 5,632,302 discloses an overflow protection shut-off device for use with a water heater. 
     An investigation of this prior art shows that most of the patents, such as U.S. Pat. No. 4,845,472, U.S. Pat. No. 5,428,347, and U.S. Pat. No. 5,655,561 generate audible alarms to signal a detected leak. Of these U.S. Pat. No. 4,845,472, U.S. Pat. No. 5,428,347, and U.S. Pat. No. 5,655,561 additionally disclose the use of solenoid-actuated valves in the water supply line. U.S. Pat. No. 5,229,750 and U.S. Pat. No. 5,632,302 also disclose the use of solenoid-actuated valves to cut off a water supply. U.S. Pat. No. 5,029,605 points out that deposits that accumulate in pipes and valves over a period of time may impede the actuation of solenoid-type valves. Also avoiding the use of solenoid actuated valves is U.S. Pat. No. 5,240,022, which incorporates a ball valve in the water supply line. To hold the ball valve in an open position it is coupled to a rotor and a spring is attached to the rotor exerting a counterclockwise torque on the rotor. The rotor is then locked in a valve-open position by a latching arm. The end of the latching arm contacts a trip arm that receives its retaining torque from a wire spring. A trip wire actuates the trip arm. This trip wire is a metallic memory alloy wire which contracts when heated. Heating is effected by a circuit actuated by the water detector. As a consequence the latch aim is released and the rotor rotates to a valve-closed position. 
     Also of interest for disclosing a ball valve is U.S. Pat. No. 5,334,973. This valve controls flow into a hot water tank by using a mechanical drive in conjunction with a multilayer moisture sensor which encases the water tank liner. 
     While U.S. Pat. No. 5,240,022 overcomes the problems of solenoids, it is subject to several disadvantages. In addition to requiring a rotor, a latching arm, a trip arm, a trip wire and various springs, allowances had to be made for the ball valve high rotational forces, primarily due to the friction between the valve ball and the O-ring seals. In addition the ball valve must be reset to its open position by turning a knob, which frequently is not always easy. The invention herein provides an improvement which permits the use of a ball valve without the problems encountered in U.S. Pat. No. 5,240,022. All of the above mentioned patents are incorporated herein by reference. 
     This leak detection and shut-off apparatus is an improvement over the known prior art apparatus. 
     SUMMARY OF THE INVENTION 
     The prior art describes a water shut-off system that incorporates a water shut-off valve adapted for installation in a water supply line, and for turning off a supply of water when a leaking condition exists. That system utilizes a device consisting of a pair of adjacently disposed electrodes which conduct an electric current when water is present. Also included with the device is a radio frequency transmitter adapted to transmit a digitally encoded signal when the said electric current is sensed. A receiving means receives that radio frequency signal. On the reception of the signal the receiving means actuates an electrical circuit so that the said electrical circuit can close the water supply line shut-off valve. By the invention herein such a water shut-off system is improved. 
     By this invention a timing logic is incorporated in the actuated electrical circuit. This timing logic causes current flow to a motor as electric pulses. The motor has a drive shaft which is geared down to provide a reducer output shaft which rotates slowly, and that output shaft is coupled to a ball valve. The ball valve requires a rotation of ninety degrees from open to closed, and a further ninety degree rotation from closed to open. A cam operated switch is also coupled to the output shaft. The cam switch prevents current flow to the motor after a ninety degree cycle, which either closes or opens the valve. When the valve closes a reset switch must be used to actuate the timing circuit to initiate the flow of current to reopen the ball valve. 
     It is an aspect of this invention to provide brake means adapted to prevent further drive shaft rotation when the cam switch prevents current flow. 
     It is an aspect of this invention to provide that a microprocessor timed signal prevents interruption of a valve operating cycle due to “close valve” signals being received from both manual and automatic inputs within a predetermined time interval, and another aspect to provide that the status of the ball valve is stored in the microprocessor in the event of the ball valve in the event of AC power failure. 
     It is another aspect of this invention that the cam means is provided with cam surfaces adapted to depress and release a double throw pushbutton cam switch so that said switch alternately cuts off current flow actuated by the receiving circuit and the reset switch. 
     It is yet another aspect of this invention to provide that the generated electric pulse is a five second pulse and the motor drive shaft speed is eight to ten rpm. 
     This leak detection and shut-off apparatus is relatively simple and inexpensive to manufacture, easy to install and efficient for its intended purpose. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a water detecting and transmitting unit. 
     FIG. 2 is a front view of a control and ball valve unit. 
     FIG. 3 is a view looking at the inside of the front cover showing circuit boards. 
     FIG. 4 is a front view partially in section showing the ball valve and spacer plate. 
     FIG. 5 is a front view with the plate removed to illustrate the motor and reduction gear housing. 
     FIG. 6 rear view showing the back of the motor and the microswitch assembly. 
     FIG. 7 is an enlarged view diagrammatically showing the cam means and microswitch. 
     FIG. 8 is a block diagram of the overall electrical system of the invention, and. 
     FIG. 9 is an enlarged, somewhat schematic view of the electric motor brake. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As previously observed, provided herein is a system for closing a valve to shut off a water supply in the event of a leak. The system is shown in FIGS. 1 and 2. FIGS. 1 and 2 are views of the two functioning units of the invention, illustrating their external appearances, that is, the way they look when purchased. The system includes a sensing and transmitting unit  2 , including a water sensor and an encoder/transmitter together constituting a water detector, and a receiver or operating unit  3 , including a motor unit and a control unit. A valve assembly including a ball valve  6  (FIG. 2) is also part of the system and all of these will be specifically described presently. 
     The invention herein will first be described in general terms by referring to FIGS. 1 and 2. The details will then be set forth by reference to the remaining figures. Sensing unit  2  includes two electrodes or probes  8  electrically connected by cable  9  to radio transmitting unit housing  10 . The two electrodes become conductive when in contact with water. Hence they are placed in the vicinity where a leak is likely to occur. On becoming conductive, sensing unit  2  generates an encoded signal which is transmitted to the receiving unit  3 . Sensing unit  2  is powered by batteries housed in transmitting unit housing  10 . The receiving unit  3  mounted in housing  4  includes a motor  39  (FIG.  5 ), and the receiving unit and the motor are powered by the 110 VAC building current through plug  13  and power cord  14  as shown in FIG.  2 . Further, showing on the face of the motor control unit housing top  22  are a valve position indicator lights  15  (green for open) and  16  (red for closed), a reset membrane switch  17  for reopening the valve, and an override membrane switch  18  which can be used to close the valve. 
     Referring now to FIG. 3, a circuit board  20 , constituting a part of the control unit, is mounted inside the top  22  of receiving unit housing  4 . Circuit board  20  includes a microprocessor  54  to be discussed shortly and a receiving circuit such as a superheterodyne radio receiver or other conventional receiving circuit which detects and decodes the signal received from sensing unit  2 , by means of a receiver/decoder  53 . The circuit board  20  also includes a semiconductor AC power switcher  55  which actuates motor  39  as will also be described in more detail. 
     The ball valve  6  is conventional, but it is illustrated in FIG. 4 so that the coupling employed for its attachment to receiving unit  3  can be visualized more readily. The valve includes the ball  30  whose opening  32  has a diameter approximating the diameter  33  of the water pipe. Ball  30  is seated in valve seat  34  which is provided with suitable O-ring seals such as  35 . To adapt the ball  30  to the reducer output shaft  36  so that the ball can be rotated thereby, stirrup member  37  is connected to the ball by bolt  38  or other means. Also, the tip of reducer output shaft  36  is shaped so that it slidably fits in the stirrup of stirrup member  37 . In order to mount ball valve  6  on the motor housing  4 , a spacer  40  is employed as illustrated in FIG.  4 . As shown, the ball flange  31  is attached to the spacer  40  by four bolts  28 . The spacer is attached to the housing body  4  and the gear reducer  44  by two bolts  29  and also stabilizes the unit when the motor is running. 
     Motor  39  can best be seen in FIG.  6 . It includes a coil or windings  41  and iron core  42 . As shown in FIG. 5 reduction gearing  44  reduces drive shaft speed from about 3,000 rpm to less than 10 rpm, say 8 or 9 rpm. 
     Also housed in housing  4 , as shown in FIGS. 5-7 as part of the control unit is a cam means coupled to AC motor  39 . The cam means includes cam wheel  46  providing the cam surfaces, and a single pole changeover microswitch  45  having a pivoted detent or pawl  43  having an outstanding tip  47  engageable with the microswitch button  45 a which can best be seen in FIG.  7 . On referring to FIG. 7 it will be seen that cam wheel  46  has two radially elevated surfaces  48  and two radially recessed surfaces  49 . When the cam wheel  46  rotates ninety degrees the positions of those four surfaces are reversed as illustrated by the phantom lines in FIG.  7 . The direction of rotation of cam wheel  46  is shown by the arrow in FIG.  7 . It is to be noted that each time detent  43  moves from a higher point x to a lower point y, the microswitch  45  is thrown or tripped. Each time the switch is thrown, current to the motor is cut off and the motor  39  stops. This power cut-off occurs each time the gear reducer output shaft  36  rotates ninety degrees. 
     In the embodiment shown, the motor  39  is provided with a brake assembly  60  as shown in FIG.  9 . The motor  39  is mounted between the gear reducer  44  and mounting plate  62  by bolts  64  which pass through and, by means of spacers  63  and  65 , locate the motor core  42 . The motor core includes an opening  67  in which the motor armature  66  rotates by virtue of the motor shaft  68  mounted between the gear reducer  44  and the mounting plate  62 . As shown, a clutch pad  70  is fixedly attached to the inside of the mounting plate  62  and a similar clutch pad  72  is mounted to the end of the motor armature. A compression spring  74 , disposed about the motor shaft  68 , extends between the gear reducer  44  and the armature boss  76 . When the motor  39  is deenergized, the clutch brake pads are engaged. However, when the coil is energized, the armature is pulled into the core opening a distance shown by “d”, which compresses the spring  74  and disengages the clutch brake pads permitting the motor to rotate. At 8 rpm, the cam wheel  46  rotates through one quadrant in just under 2 seconds. The pulse delivered to the motor is 5 seconds. Thus, to ensure that the valve does not partially close or open due to inertial and other effects, the brake prevents further drive shaft rotation after the cam switch cuts off the power to the motor. 
     Having described the component parts or hardware foaming this invention its operation will now be discussed. Referring to the block diagram FIG. 8, the invention includes three units, water detector  50 , control unit  20 , and cam switch  45 . Initially, with the ball valve open, cam switch  45  is set to position a-c and motor  39  is stationary. Upon detection of a water leak, water detector  2  sends an encoded signal via an RF link means  51  to the receiver decoder  53  which in turn sends a signal to microprocessor  54  in the control unit timing circuit. The microprocessor  54  in the control unit is quiescent until it receives a signal from either the water detector  50  or the pushbutton of the membrane switch  18  in FIG.  2 . Either of these two signals initiates a 5 second power pulse from the microprocessor which is fed to motor  39  via the AC power switcher  55  and the cam switch a-c path. Motor  39  then rotates through ninety degrees, turning the ball valve off, while cam wheel  46  and microswitch detent  47  change cam switch (the microswitch)  45  from position a-c to b-c thus interrupting power and arresting the motor. 
     To open the ball valve, the manual “press to open” or membrane reset button  17 FIG. 2 must be momentarily pressed. Microprocessor  54  then responds by generating a 5 second timing pulse which is received by the AC power switcher  55  and passed on to motor  39  through cam switch  45 , now in position b-c. Motor  39  again rotates through ninety degrees, turning the ball valve on, restoring the cam switch position to path a-c as detent  47  rises, again stopping the motor. If for any reason it now becomes necessary to close the ball valve manually, the “press to close” membrane switch  18  (FIG. 2) can be momentarily pressed. The AC power switcher  55  then operates as previously stated, in a manner similar to its having received a “close valve” signal from the water detector  2 . Status light  16  and indicator lights  17  and  18  (FIG. 2) are provided to show whether the ball valve is open or closed. 
     The microprocessor  54  also performs two other functions benefitting the operation of the leak detecting apparatus. The first is to introduce a delay of a few seconds time, greater than 5 seconds, in responding to sequential “valve closed” and “valve open” pushbutton operations. This short delay ensures that the 5 second ball valve operating cycle, once initiated, is not interrupted by premature or redundant push button inputs. Should a potential signal conflict ever occur (a race condition) due to a water detector “close valve” signal and a manual “close valve” signal being issued, the first signal received is processed with an uninterruptible 5 second delay, thus avoiding an incompleted valve closing cycle. The second function is to store in internal logic the status of the ball valve (whether open or closed) in the event of an AC power failure. This logic function ensures correct system operation when power is restored. 
     Having been given the teachings of this invention ramifications and will occur to those skilled in the art it being understood that by making detailed reference to a preferred embodiment, such detail is to be understood in an instructive sense rather than in any restrictive sense, many other variants being possible within the scope of the claims hereunto appended. 
     We claim as our invention: