Abstract:
Fluid sensing shut-off devices with timer and methods of operation to shut off fluid flow if a primary shutoff valve sticks in the on condition. An embodiment is disclosed using a microphone to sense fluid flow, with a microprocessor periodically awakening from a sleep mode to power the sensor and determine if there is flow. If there is flow, the microprocessor times flow, and if flow is not shut off within a predetermined length of time, the microprocessor shuts off the valve. The valve itself normally held in a magnetically latched, valve open state, but may be unlatched by a current pulse to close the valve. Various embodiments and applications are disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of U.S. Provisional Patent Application No. 60/672,784 filed Apr. 19, 2005. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention prevents the wasting of water in toilets. 
   2. Prior Art 
   Presently, toilet water is being wasted because of faulty flush mechanisms. This invention addresses this problem. 
   Known automatic fluid shut-off valves include those disclosed in U.S. Pat. No. 4,501,290 issued to Sturman et al. on Feb. 26, 1985. In FIGS. 2-3 of Sturman et al., a pressure regulating electrically operable shut-off valve is shown having a permanent magnet 84 that is used to latch a third magnetic member 98 with a magnet member 82. 
   Also known automatic fluid shut-off valves, in FIGS. 1-2 of U.S. Pat. No. 6,481,689 B2 issued to Grill on Nov. 19, 2002, there is shown a two-way two-position fluid control valve having a solenoid 48. When the solenoid 48 is electrically actuated, an armature 58 is pulled into contact with a core 56 while a transfer tube 42, and a valve 26 coupled to the transfer tube 42, move from a first (closed) position shown in FIG. 1 to a second (opened) position shown in FIG. 2. While the fluid control valve of Grill is suitable for many applications, the solenoid 48 disclosed therein for both i) electromagnetically pulling the armature 58 (and valve 26) from its closed position to its opened position, and ii) holding the armature 58 (and valve 26) in its opened position may be unsuitable for other applications. For example, it may be too expensive and/or too power consuming for certain automatic fluid shut-off applications, such as those found in various places of the common household. 
   Also known in U.S. Pat. No. 6,820,856 B2 issued to Grill Nov. 24, 2004, is a two-way two-position control valve assembly operable to manually open and automatically block fluid flow therethrough. 
   It is therefore desirable to provide a simple, energy-efficient, reliable, relatively inexpensive two-way fluid control valve assembly for various household and commercial applications that senses fluid flow and automatically shuts off the valve when a preset time limit has expired. 
   The present invention discloses a two-way fluid control valve with a sensor that sense fluid flow and automatically shuts off the valve when a preset time limit has been reached. When fluid flow stops, the timing mechanism resets to zero. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-section assembly drawing of the valve. 
       FIG. 2  is a full view of the assembled valve. 
       FIGS. 3 and 4  are circuit diagrams of the electronics used with the preferred embodiment of the present invention. 
       FIG. 5  is an illustration showing the configuration and mounting of the electronics and power supply to the valve body of the preferred embodiment. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   One embodiment of the present invention is its use on the water inlet of a toilet to detect a leaking toilet valve, and shut the running water off after a preset time to prevent the costly and environmentally unwise waste and loss of water. 
   The sensor could sense fluid by an electronic sensor, by using a probe, by sensing water level, or by detecting fluid flow audibly. 
   The valve could be reset manually, mechanically, electronically, or automatically. 
   The fluid valve could shut off a variety of fluid flow, i.e., household water, gardening, irrigation, gas. 
   The shut-off device could be powered by virtually any source of power, i.e., AC or DC powered, solar, or powered by mechanical means. 
     FIG. 1  is a cross-section of the valve of one embodiment of the present invention taken through the inlet  20  and outlet  22  of the valve. The valve body  24  supports, at the left side thereof, what is referred to herein as a lower diaphragm support  26  and a spring housing  28  fastened to the valve body  24  by screws  30 . At the right side of  FIG. 1 , the valve body  24  supports an actuator housing  32  held in place by screws  34 . Within the valve body is a shaft  36  sealed against leakage by diaphragms  38  and  40 , retained in position on the shaft by center diaphragm supports  42  and  44 , which in turn are held in position by spring clips  46  and  48  in grooves in shaft  36 . 
   The shaft  36  supports a seat rubber  47  within seat rubber housing  49 , also held in position on the shaft by spring clips  50  and  52 . O-ring  54  provides a seal between the valve body  24  and the lower diaphragm support  26 , with O-ring  56  providing a further seal along shaft  36  whenever the seat rubber  46  is forced against seat  58  in the valve body. At the left end of the assembly of  FIG. 1 , a preloaded spring  60  pushes against a spring guide  62 , which in turn pushes against the spring clip  46  and center diaphragm support  42  to encourage shaft  36  and the various parts coupled thereto toward the right. 
   At the right side of the Figure is an actuator support  64  and a cup shaped magnetic lower frame  66  with an annular magnet  68  at the right end thereof. A magnetic plunger  70  has a slip fit in the magnet  68 , with the end of the plunger touching the right end of shaft  36 . The assembly of the lower frame  66  and magnet  68  is held in position by an upper frame  72  and the actuator housing  32 . Also within the cup shaped lower frame  66  is a bobbin  74  with a coil of wire  76  thereon. 
     FIG. 1  actually shows the valve in an intermediate position between its open position and its closed position. In particular, when plunger  70  is pushed to its left-most position against the force of spring  60 , the left face of plunger  70  will abut the adjacent face of lower frame  66  to form a substantially zero air gap magnetic circuit having a circuit portion comprised of lower frame  66  and the magnet  68  and a second portion comprising the plunger itself. This is a substantially zero air gap magnetic circuit because the left face of plunger  70  is in contact with the adjacent face of lower frame  66  and for the reason that the plunger  70  is a slip fit within magnet  68 . Thus there is a substantial magnetic force that will hold the plunger  70  in its left-most position, the magnetic force and the spring force of spring  60  being portioned so that when the plunger is in its left-most position, the magnetic force will exceed the spring force to hold the valve in the open position. However, a current pulse through coil  76  of sufficient amplitude and duration and of appropriate sense will sufficiently reduce the magnetic flux density between the left face of plunger  70  and the adjacent face of lower frame  66  to reduce the magnetic force on plunger  70  to a magnitude less than the force of spring  60 . Thus upon occurrence of such a pulse, spring  60  will cause shaft  36  and the parts attached thereto, as well as plunger  70 , to move their right-most position, forcing seat rubber  47  against seat  58  in the valve body  24  to close the valve. When closed, seat rubber  46  will be firmly against seat  58  to seal against the seat, with O-ring  56  sealing along the shaft  36  to help prevent valve leakage. When the current pulse through coil  76  is terminated, the valve will stay in the closed position because the air gap now existing between the left face of plunger  70  and the adjacent face of lower frame  66  limits the flux density recovery in this area, thereby providing a magnetic valve opening force which is now less than the force of spring  60  holding the valve closed. The valve may be manually reset, however, by pushing plunger  70  to the left-most position, opening the valve and again magnetically latching the valve in the open position with the left face of plunger  70  against the adjacent face of lower frame  66 . 
     FIG. 2  is a view of the assembled valve without electronics. The parts viewable in that assembly are the valve body  24  with inlet and outlet ports  22 , the actuator housing  32  held on by screws  34 , plunger  70 , lower diaphragm support  26  and spring housing  28  held in the assembly by screws  30 . 
   The electronics for controlling the fluid sensing shut-off device of the preferred embodiments of the present invention may be seen in  FIGS. 3 and 4 . The upper part of  FIG. 3 , generally indicated by the numeral  78 , merely illustrates the battery power supply, in a preferred embodiment comprising three AA batteries with various size capacitors suppressing noise and diode D 1  providing reverse voltage protection. In the lower part of the circuit of  FIG. 3  is a microprocessor (μP) with a conventional crystal oscillator circuit  80  providing a reference clock input for the microprocessor. The microprocessor is programmed to periodically wake up from a sleep mode and provide sensor power on line  82 , which powers the circuit on  FIG. 4 , specifically applying sensor power through resistor R 1  to a flow sensor, in a preferred embodiment a microphone M 1 , as well as to power dual operational amplifiers A 1 , operational amplifier A 2  and comparator C 1 . The microphone M 1  is disposed within the body of the valve in the final assembly and may touch the body or be slightly spaced from the body, though in either event, responding to the flow noise of fluid flowing through the open valve. Amplifiers A 1  and A 2  have the positive inputs thereto biased by the voltage across resistor R 2 , with the positive input to comparator C 1  being one diode voltage drop higher than that voltage as a result of the voltage drop across diode D 2 . Consequently when there is no fluid flow, and thus no microphone input, the outputs of amplifiers A 1  and A 2  will be equal to the voltage on their positive inputs, namely, one diode voltage drop below the positive input to comparator C 1 . Thus with no flow the output of the comparator on line  84  will be high. This holds the output of the precision monostable multi-vibrator MV fixed pr stable, which is sensed by the microprocessor μP before reentering the sleep mode. If, however, flow has been initiated through the valve through the opening of another valve in series therewith, the flow sensor, microphone in the preferred embodiment, will provide an output that when amplified by amplifiers A 1  and A 2  of  FIG. 4 , will cause the output of comparator C 1  to oscillate, thereby triggering the multi-vibrator MV to provide an alternating state output to the microprocessor μP. The microprocessor, on sensing that alternating input, will start timing the duration of that alternating input until either the alternating input stops or the time of flow reaches a predetermined duration, after which the microprocessor will turn on MOSFET MOS 1  to apply the voltage Vl,V 2  across the coil of the valve of  FIG. 1 . In that regard, MOSFET MOS 2  is merely diode connected to absorb the back EMF from the coil when MOSFET MOS 1  is subsequently turned off. The microprocessor μP will turn on MOSFET MOS 1  long enough to reduce the magnetic field and thus the magnetic force pulling plunger  70  to the left-most position, allowing spring  60  to force the valve to the right-most or closed position, after which the current pulse may be terminated, with the valve remaining in the closed state until plunger  70  is again manually pushed to the left as viewed in  FIG. 1 . 
   Also shown in  FIG. 3  is a low voltage sensing capability. In particular, a voltage divider generally indicated by the numeral  86  provides two measures of the battery voltage VBAT to a dual ultra-low power comparator  88  with internal reference, which will provide two outputs, one indicating a low battery (the word battery as used herein an in the claims including multiple batteries) and the other output indicating the battery is so low as to risk malfunction of the sensing system if the valve is not immediately closed. Thus on first sensing the low battery, the microprocessor will provide an output to cause a low frequency flashing of light-emitting diode LED 1 , with a still lower battery voltage indication causing the microprocessor to pulse MOSFET MOS 1  on to close the valve. 
   Now referring to  FIG. 5 , the manner in which the electronics and battery power supply attach to the valve body  24  may be seen. In particular, case  90  houses a printed circuit board with the microprocessor μP and other electronics therein, with cover  92  covering the three AA batteries for the battery power supply. The microphone in the preferred embodiment is mounted on the printed circuit board itself and extends into the valve body  24  for picking up the sound and vibrations from the turbulent fluid flow through the valve. 
   The preferred embodiment of the present invention is intended for use in the water supply line for a toilet to shut off the water flow in the event the normal toilet water flow shut-off valve malfunctions for any reason. However, the present invention may be used in other instances to preserve water or protect property in systems wherein normal water flow either occurs for a predetermined time period, or at least for a predetermined maximum time period. For instance, one such other use may be in the water supply line to an ice cube maker in a refrigerator. In this application, if the solenoid valve supplying water to the ice cube maker locks in the valve open condition, substantial property damage can result unless an automatic backup shut-off valve is used, such as the present invention valve. Other applications could include dishwashers and clothes washers, irrigation systems, and the like, wherein much water can be wasted and substantial damage property can result from a valve stuck in the on position. In that regard, valve systems in accordance with the present invention may readily be scaled to accommodate large or small flows as required. By having the microprocessor in the sleep mode a large majority of the time, battery life in the system of the present invention may approach the shelf life of the batteries. Obviously the valve systems of the present invention could be powered from 110V AC power, though battery power is preferred to minimize installation difficulty and cost. Also while a microphone and microprocessor based system has been disclosed herein, obviously other types of flow sensors and control electronics may be used as desired. In that regard, the flow duration before automatic shut-off could be varied for different applications, and if desirable, could be made field programmable. Thus while certain preferred embodiments of the present invention have been disclosed and described herein for purposes of illustration and not for purposes of limitation, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.