Abstract: A method and apparatus for detecting the presence of an organic fluid has a pair of strips of fabric-like material joined together at one end in overlapping fashion by a bond formed from an organic fluid imbibing material sorbed into the common ends of the strip. The imbibing material is a latex polymer such as tertiary-alkylstyrenes. When the organic fluid contacts the bonded joint the imbibing material softens. A tensile force may be applied across the bonded joint by a resilient member which may be connected to mechanism for actuating electrical circuitry to signal the disjoining of the strips when the joint is softened sufficiently by the presence of the organic fluid.

Abstract: A moisture intrusion detection system is provided, wherein a plurality of independent and insular moisture detecting units are placed in a predetermined spaced apart relationship across the surface of a roof structure, or other system incorporating a water impermeable membrane, beneath the water impermeable membrane thereof. Each of the detecting units includes a moisture detecting and power supply unit and signalling unit. When moisture penetrates the water impermeable membrane of the roof structure, a leak condition exists and a water activated battery is activated. Each detecting unit in contact with water is activated. In combination with the detecting units, position and direction locator apparatus are used in combination with the detecting units to localize the source of the leak and the extent of any water damage caused thereby.

Abstract: The present invention relates to a water detection subassembly and method for forming same, for use in association with water detection system operating within a digital computing center. The subassembly includes a perforated protective semi-circular shield fitted about a fabric mesh supporting copper conductors connected to a low voltage source. The perforations of the shield are formed into two distinct patterns: The first series comprises sets of openings adjacent to the apex of the shield and periodically spaced therealong. Each opening has a common arcuate length L, a width W, and an internal spacing S and, more importantly, is of sufficient dimension to allow easy entry of aerosol mixtures of air and water droplets originating from above the shield.

Abstract: A device for detecting the presence of water in a fuel tank comprising a fitting mounted at the lower most portion of said tank having a water sensing alloy on said fitting. The fitting positions the water sensing alloy in the tank in the position where water will tend to collect. The fitting also includes an integrally mounted indicating device such as a go/no-go device or a meter to determine the presence of water in the tank. The length by which the fitting extends into the tank can be used to determine the depth of water in the tank and when the amount of water collected at the bottom or sump of the tank exeeds a predetermined depth it will be detected by the indicator connected externally to the water sensing alloy. A useful water sensing alloy is comprised of a composition of lead, tin, and zinc each being present in an amount of between about 20-45% by weight, with the composition also containing small amounts of up to about 0.

Abstract: Safety device used in the detection of a conductive liquid in an enclosure to be monitored, in which the variation of the resistance as a result of the presence of the liquid between electrodes triggers an electrical alarm circuit, wherein it comprises in combination: a liquid detecting member constituted by two spaced electrodes and forming four contacts; a first field effect transistor, whose gate, source and drain terminals are connected to a power supply and to the four aforementioned contacts in such a way that the first field effect transistor is non-conducting when the conductive liquid is absent and where there is no deterioration to any one of the connections connecting the terminals of the first transistor to one or other of the said contacts; and a second field effect transistor, whose source and drain terminals are connected to a second power supply and whose gate terminals are connected to the drain terminal of the first field effect transistor in such a way that the second transistor is conducti

Abstract: Corrosion of a water sensor resulting from the passage of considerable electric current through it while it is in contact with water is prevented in a motor fuel filter equipped for water separation by interrupting or greatly reducing the current passing through the sensor after the sensor has given a signal indicating the presence of water in sufficient quantity to require draining soon. The warning provided to the vehicle driver is maintained thereafter either by a signal storage circuit (flipflop) or by causing current diverted from the sensor to flow through a substitution resistor or a shunt transistor.

Abstract: A portable device for detecting when undergarments are wet with urine comprises electronic disposable sensor means in contact with said undergarment, an electronic detector means activated by said sensor means, and an alarm means activated by the detector means, all chosen and constructed such that there is no energization of any part of the system until a wet condition is detected and such that there is no possibility of more than 9 volts of electric potential in contact with the human body, with the current generated by said potential not to exceed 10 microamperes.

Abstract: The present invention relates to a water detection subassembly and method for forming same, for use in association with water detection system operating within a digital computing center. The subassembly includes a perforated protective shield fitted about a fabric mesh supporting copper conductors connected to a low voltage service. In that way, the shield completely isolates the fabric mesh and copper conductors against abuse such as provided from workmen's shoes coming into contact with the subassembly during repair, replacement or renovation of computing equipment at the center.The shields are conveniently formed from commercially available plastic pipe such as PVC, sliced longitudinally and then attached to the concrete sub-floor of the computing room along the two cut longitudinal surfaces. Since a pair of shields can be formed from each section of plastic pipe, the shields are inexpensive to manufacture.

Abstract: The domestic and commercial automatic soil moisture indicator of the present invention employs a pair of probes which are conductive traces (e.g. a printed circuit board) that are coated with material for corrosion and electrolysis resistance to enable long term residence in potted plant soil. The device provides alternating short pulses across the probes to further enhance near zero electrolysis and increase potted plant soil residence time without probe wear. It has a single light emitting diode indicator lamp to blink every ten seconds when soil drops below a customer set level, and a beeper (e.g. piezoelectric ceramic) to sound a beep in unison with the LED flashing during dry soil indication as well as a calibrated-numbered user adjustment to set the dry soil indication level. A coil operating with an integrated circuit DC to DC converter functions to yield operation from a small battery to keep the overall unit small and electric drain down.

Abstract: A liquid water sensor, useful for indicating a corrosive condition in a natural gas pipeline, comprises a plurality of electrically conductive members spaced from each other by an insulating medium and in series with an electrical continuity detector. The conductive members are spaced at a distance sufficient to enable a droplet or film of water to bridge such conductive members to provide a conductive pathway therebetween and thereby provide a signal at the continuity detector. An electrical circuit is also provided which includes a heater for heating the conductive members to evaporate liquid water therefrom and an output circuit for indicating whether liquid water was present or another conductive material having a boiling point greater than water, e.g. ferrous sulfide, continues to provide a conductive pathway between the conductive members after cessation of heating.

Abstract: This invention is directed to a system for detecting the presence of moisture in a given location such as the attic of a building or house before the moisture has had an opportunity to penetrate plaster walls or cause other damage. The disclosed invention includes a detector for detecting the presence of minute quantities of moisture contemporaneous with their initial appearance, which responds to the presence of moisture by exhibiting a decrease in its internal impedance. An audible signal-generating circuit is coupled to the detector and responds to the resultant decrease in the impedance of the detector by commencing to oscillate at a pre-determined audio frequency.

Abstract: Apparatus for monitoring electrical cables for the presence of moisture within the cable along the full length of the cable and at specific points such as splices along its length comprises a pair of dielectrically separated conductors arranged along the length of the cable for communicating between a central station and remote stations along the length of the cable at the specific points to be monitored. The remote stations each include a further dielectrically separated pair of conductors for sensing moisture at the point and signals along the first pair of conductors to the central station. The central station detects moisture by an increase in current in the conductors and also detects a signal from remote stations.

Abstract: An automatic power shut-off circuit for a wide variety of electrical appliances, such as hand-held hair dryers, razors, irons, hair curlers, etc. which pose a risk of electrocution when used around water. Thus, said circuit avoids the risk of dangerous shocks or even death, if the appliance should fall into a tub of water in which someone is bathing or if someone reaches or steps into water containing a plugged-in appliance, regardless of whether the switch of the appliance is on or off.

Abstract: The invention disclosed is an indicator for monitoring the capacity of a CO.sub.2 absorbent to absorb CO.sub.2. The indicator is typically used in association with a closed circuit breathing apparatus, including a container for a CO.sub.2 absorbent. The indicator comprises temperature sensing means immersed in the absorbent, a temperature to voltage converter for converting a sensed temperature reading to an electrical voltage signal, temperature trend processing means for processing said electrical voltage signal into a selected electrical output signal characteristic of a temperature trend; and display means for converting said selected electrical output signal to a predetermined visual display indicative of the capacity of the CO.sub.2 absorbent to absorb CO.sub.2.

Abstract: This invention relates to a device for sensing moisture on a metal surface such as a brake path. Since the presence of moisture on a brake path causes inefficient working of the brake, it is necessary to test for moisture. Originally this was done by hand. The present invention provides a device which can test for moisture automatically. The device comprises a pair of contacts urged against an electrically conducting surface. One contact is covered by a strip of material, for instance paper, which is an insulator when dry and a conductor when moist. If moisture is present an electrical circuit comprising the surface, the moist material and the two contacts is completed activating an alarm. The material may be salt impregnated and the contacts may be moveable over the surface. The device is for use in testing for moisture on the braking surface of colliery winding installations.

Abstract: A fluid delivery monitor having a flow sensor, accumulator for recording the duration of sensed flow, a code device to display the contents of and reset the accumulator upon entry of a preselected sequence, and a fluid sensor to disable the accumulator for sensed conductive fluid. The flow sensor is a pressure-sensitive switch recessed in a radial port and a vane substantially covering the port protects the switch from tampering and directs fluid toward the switch.

Abstract: An overflow control system for use with home appliances such as washing machines, incorporating conventional stand pipe which receives the outlet conduit from the appliance, the stand pipe being provided with an attachment having a displacement, conductivity or a pressure sensor installed for sensing the height of liquids in the stand pipe. This stand pipe may be vertically connected to the sewage line outlet found in a home and the signals from the sensors may be used to shut off the power to the appliance and to excite an alarm. Connected in parallel with the sensors may be a moisture sensor deployed under the appliance which again shuts the power off whenever the machine is inadvertently filled beyond its limits or when leakage occurs.

Abstract: This invention relates to a method of detecting the presence of a conductive fluid such as water in a chamber such as the oil pan of an internal combustion engine and apparatus for carrying out the method. A resilient flexible sensor probe is mounted in the oil drain and electrically connected to an alarm which is activated by current flow. The sensor probe has an outer electrode member with a portion formed of a helical coil through which an insulated wire runs to form an inner electrode member. The inner electrode member is connected to the alarm, while the outer electrode member is grounded to the engine. The sensor probe bends to a position where its inner end portion depends into contact with the bottom of the oil pan. The inner electrode member ends at a bare tip which is surrounded by an insulative sleeve which prevents direct contact with the bottom of the oil pan. The outer electrode member ends at a bare wire portion which is spaced a short distance from the tip of the inner electrode member.

Abstract: A system for signaling emptying of a beverage storage container of a beverage dispensing system before any substantial amount of gas enters the delivery line between the container and a dispensing valve. No signal system components are in the container; instead, a fitting is mounted in the delivery line adjacent the container with two electrodes spaced from and electrically insulated from one another within the fitting for contact with the beverage. Sensing circuitry determines whether beverage bridges the two electrodes and causes signaling on non-bridging of the two electrodes by beverage in the line to indicate that the container is empty.

Abstract: A grain moisture testing apparatus which can be used for testing of moisture content of other organic materials includes means to hold and crush the material against conductance measuring electrodes. These electrodes form one element of a voltage divider, the other element of which is formed by a resistor which is selectively adjustable among several distinct values. The resistance between the two electrodes, and thus the moisture content of the material proportional thereto, is determined by applying a constant voltage across the divider and sensing the voltage occuring across the electrodes. The voltage sensor is designed as a threshold switch which gives a simple Pass/Fail indication of acceptable moisture level. The apparatus also includes voltage supply testing means and circuit temperature testing and compensation means to assure the validity of the test.

Abstract: A cable assembly for detecting the ingress of water inside a cable is disclosed. The cable assembly comprises a moisture detecting tape constructed of two parallel bare conductors laminated to an insulating substrate. The tape thus constructed is applied in an open helix around the conductor core of a cable. A suitable plastic jacket is extruded over the cable core and the moisture detecting tape. A shielding tape may also be applied over the cable core and the moisture detecting tape prior to extrusion of the overall plastic jacket. The cable thus constructed with the integral moisture detecting tape is adapted for connection to a suitable sensing apparatus at one end, and should moisture enter the cable as a result of damage to same, the electrical characteristics of the detecting tape would change and such change will result in a measurable conductance between the conductors of the moisture detecting tape. The ingressing water is thus sensed prior to penetrating and compromising the cable core.

Abstract: An overflow control system for use with home appliances such as washing machines, incorporating conventional stand pipe which receives the outlet conduit from the appliance, the stand pipe being provided with an attachment having a displacement, conductivity or a pressure sensor installed for sensing the height of liquids in the stand pipe. This stand pipe may be vertically connected to the sewage line outlet found in a home and the signals from the sensors may be used to shut off the power to the appliance and to excite an alarm. Connected in parallel with the sensors may be a moisture sensor deployed under the appliance which again shuts the power off whenever the machine is inadvertently filled beyond its limits or when leakage occurs.

Abstract: A moisture sensing device for application to water pipes and the like utilizes a pair of closely spaced electrical conductors partially positioned in an elongated flexible insulating member which can be adhesively affixed to a water pipe or the like with the spaced partially exposed electrical conductors in oppositely disposed relation to the pipe. An alarm actuating circuit is connected with the spaced conductors and arranged to initiate an alarm when moisture bridges the closely spaced conductors.

Abstract: A system for providing an alarm in the event of a bed wetting occurrence is presented which includes a pair of electrodes fabricated from permanent magnets which are positioned adjacent to each other and held apart by a thin spacer. A self-latching relay is responsive to the completion of an electrical circuit between the electrodes which during the normal application of the invention is caused by an electrolyte such as urine flowing in the space between magnetic electrodes to activate a nurses call system through the use of pulsating signals.

Abstract: A sensitive element which deteriorates when contacted with the polluting agent, this material comprising a sequenced styrene-butadiene copolymer, of which at least a part is hydrogenated.These elements can be used in pollution sensing devices, or for constituting at least a wall portion of a container housing a product for fighting against pollution.

Abstract: An improved bedwetting detection device is responsive to moisture in the bed of the user to create an alarm when bedwetting occurs. The device includes controlling circuitry connected to metallic conductors (12, 14) installed in the bed of the user. The circuitry periodically provides electrical pulses to the conductors (12, 14) so as to minimize the introduction of electrical impulses into the bed of the user. Furthermore, the pulse created by the circuitry is of a very low voltage so as to further minimize the amount of electrical energy introduced into the bed of the user.

Abstract: A moisture detector comprises a shell adapted to float with an anode and cathode on the bottom portion thereof. The anode may be of sacrificial metal which is electrolyzed to increase the conductivity of moisture contacting the electrodes. Also, a water soluble electrolyte may be placed either on the electrodes or close thereto. A plug on the shell may provide for a pair of remote electrodes. A piezoelectric transducer system of improved design involves shaping of the chambers in said shell.

Abstract: A liquid detection device for energizing a warning signal. An electronic switch, of the non-latching type, is provided for coupling a source of electrical energy to a warning device responsive to a first signal at the inputs thereof. An elongated probe is provided having at least two generally parallel conductors enclosed in an insulative sheath having a plurality of apertures therein for exposing adjacent sections of the conductor. The conductors are coupled to the inputs of the electronic switching device for generating the first signal responsive to moisture being operatively coupled over the apertures between the conductors. The probe is of sufficient length in order to form a perimeter about the area in which the liquid is to be detected.

Abstract: A resistive liquid detection and shut-off system is used to protect a floor area from water damage. An elongated sensor comprising a flexible plastic tape with an adhesive backing and a pair of conductive metal strips detects liquid drips, flows and trickles, but not liquid beads. A detection circuit measures resistivity changes in the sensor, and an output circuit activates a solenoid-operated water shut-off valve in response to predetermined resistivity changes in the sensor. A connector comprising a body of electrically insulating material with electrical terminals thereon connects portions of the elongated sensor together so that they can have any length and relative position. A battery may provide the power for the entire system, with a battery voltage monitoring circuit also provided.

Abstract: A pressure fryer having a vessel adapted to cook a food product within a bath of cooking oil. Means are provided for detecting the presence of water in the vessel and the bath and for automatically disabling the heater of the fryer if water is present in such quantity as to create a potentially unsafe condition.

Abstract: A system for providing an alarm in the event of a bed wetting occurrence is presented which includes a pair of electrodes fabricated from permanent magnets which are positioned adjacent to each other and held apart by a thin spacer. A self-latching relay is responsive to the completion of an electrical circuit between the electrodes which during the normal application of the invention is caused by an electrolyte such as urine. The self-latching relay interrupts current flow to the magnetic electrodes and activates a nurses call system through the use of pulsating signals.

Abstract: A battery-powered device useful in supervising the progressive loss over a time interval of moisture in the soil of a household plant from an initial growth-promoting level to a diminished level at which replenishment is required, wherein the device has a continuously inserted, operative position in the plant soil throughout said time interval of supervision, and yet does not require frequent change of its powering batteries.

Abstract: A moisture alarm comprises a watertight system with three probes extending down as supportive legs and as ballast from a floatable body or case containing audible and/or RF pulsing-alarm circuitry responsive to moisture detected by any or all of the probes; the case is upwardly convex on top to slip from beneath fixed obstacles in rising water; a provision prevents the probe from shorting out when the unit is set on a metal deck; the free ends of the probes, each of which has a set of outer and inner coaxial electrodes, are apertured, providing access for moisture to reach the inner electrode; a mercury switch sounds the alarm when the unit is tipped over in position lifting inner electrodes from the floor but can be over-ridden by a shunt which permits the unit to be operated inverted as a randdrop alarm; a dual ring conductor embodiment is also disclosed.

Abstract: A water detector alarm is disclosed. The device includes a power supply, an alarm unit, moisture detecting electrodes and circuitry for activating the alarm unit in response thereto, and a power monitoring unit for monitoring the power supply and activating the alarm unit when the power supply grows weak, with a frequency noticeably distinct from the water presence alarm frequency.

Abstract: A compressed dehydrated cellulose sponge wafer has conductive plates attached to opposing faces. A bridging conductor electrically connects the two plates together upon swelling of the wafer responsive to its contact with moisture. One edge of the sponge is treated with adhesive so as to form a hinge. The wafer opens like a book upon contact with moisture forcing the extending plates into contact.

Abstract: A self-contained water alarm for monitoring floor moisture comprising a plurality of pairs of sensor electrodes mounted at spaced locations on the bottom of a donut-shaped housing that can be fitted over a standpipe, the sensor electrode pairs being incorporated in feet that support the housing on a floor; the housing contains a horn or other audible alarm device, a battery, and an alarm circuit including an SCR having its main anode-cathode disclosure path connected in series with the horn and the battery and in parallel with a manual test-reset switch, and having its gate electrode connected to one sensor electrode in each pair, the other sensor electrode in each pair being connected to the battery. An auxiliary pair of sensor electrodes are connected in the circuit, in parallel with the housing-mounted sensor electrode pairs, to permit simultaneous monitoring of floor moisture and of the water level in a sump or standpipe. Provision is made for connecting a remote alarm to the device.

Abstract: Circuit for controlling the program timer of a laundry dryer as a function of the moisture-dependent resistance of the laundry. A storage capacitor charged from a d-c voltage source together with laundry resistance resulting from wet laundry bridging two electrodes and resistance determine the duty cycle or frequency for an oscillator. The output of the oscillator is fed to a filter and from there as one input to a comparator. A reference value setter is fed to another input of the comparator. The output of the comparator is functionally connected to the program timer. This circuit arrangement makes possible measurement of low residual moisture values in the laundry and thereby permits the start of the post-drying phase without heating on reaching this low residual moisture value.

Abstract: A pad adapted for use with an electrically actuated signal where the pad acts as a sensor to detect involuntary emission of urine. It is designed to be worn adjacent to the body of the user. It includes a central layer of closed cell foam sandwiched between two outer layers, each fabricated from a sheet having an electrically conductive surface. At least one of the outer layers and the foam layer have discrete apertures formed through them in registry with one another to receive and collect discharged urine. The urine bridges the gap between the conductive surfaces and thereby completes a signal circuit.

Abstract: An arrangement for detecting and controlling an outflow which includes a temperature sensing device for sensing a temperature of the outflow and providing a signal of the detected temperature. A control arrangement is provided and is operatively associated with the temperature sensing device so as to effect a predetermined control operation upon the temperature sensing device providing a signal indicative of a predetermined temperature. The temperature sensing device may sense a temperature rise over a predetermined length of time or sense an increase in the temperature level.

Abstract: A conductivity sensing device for diapers comprises a pair of swingably connected jaw members spring biased to closed position. One of the jaws has an electric conducting member with jaws designed to pierce material of the diaper to contact an electrically conducting layer therein. One of the jaws is provided with an electrical conducting area designed to contact the skin of a baby. Means are provided for preventing direct electrical contact between the jaws and the conducting area and means are provided to detect an increase in conductivity between these members.

Abstract: An intrusion detection system in which crystal oscillators are used to provide a frequency which varies as a function of fluctuations of a particular environmental property of the atmosphere, e.g., humidity, in the protected volume. The system is based on the discovery that the frequency of an oscillator whose crystal is humidity sensitive, varies at a frequency or rate which is within a known frequency band, due to the entry of an intruder into the protected volume. The variable frequency is converted into a voltage which is then filtered by a filtering arrangement which permits only voltage variations at frequencies within the known frequency band to activate an alarm while inhibiting the alarm activation when the voltage frequency is below or above the known frequency band.

Abstract: A hemorrhage alarm system having an electrically operated signal device, a source of electrical current, a circuit connecting said current source and signal device, a normally open switch in said circuit and a means swelling on contact with blood and body fluid acting on said switch to close it on contact with blood and body fluid.

Abstract: An improved moisture-sensing device, preferably combined with an improved lead, is provided which represents a significant advance in the state of the art in the treatment of enuretic children. Both sensor and lead utilize a special type of conductive polyvinyl cloth and the components are connected by silver-impregnated Velcro.RTM..

Abstract: A thumb-sucking alarm system includes a pair of spaced-apart sensor electrodes carried on a moisture-accepting portion of a flexible sensor tape adapted to be wrapped around the user's thumb, the electrodes being respectively connected to conductive lead strips on an elongated coupling portion of the tape, the distal end of which is wrapped around a plug for insertion into a mating receptacle in a housing adapted to be secured by a strap around the user's wrist. The conductive strips contact terminals of a battery-powered transistorized alarm circuit in the housing which generates an audible alarm signal in response to establishment of an electrical path between the electrodes by the moisture in a user's mouth when he sucks his thumb. A test button is provided on the housing for testing the audible signal generating circuit.

Abstract: A liquid level sensing apparatus includes a housing having disposed therein circuit means and a power source for providing an indication when the liquid on a surface reaches a predetermined level. The sensing device which activates the circuit means is a disposable liquid disruptable fuse link fabricated from porous paper mounted on the arm portions of a spring means capable of activating the circuit means.

Abstract: A device which provides an aversive stimulus to a child who bed wets while asleep includes a urine detection pad of absorbent material having wire screen electrodes on both sides thereof, and an electrical circuit including an aversive alarm which is triggered when the detecting pad is moistened by a small amount of urine. A preferred embodiment of the device shuts off the alarm within a short time period if the total amount of urine deposited on the detecting pad is below a given quantity. If more than the allowable quantity of urine is deposited, the alarm continues to expose the child to the aversive stimulus. The device may also feature an adjustable threshold in its circuit to permit variation of the total quantity of urine required to continually energize the alarm, as well as selectable sensitivity of the circuit to the initial deposition of urine so that dampness caused by perspiration or humidity will not trigger the alarm.

Abstract: A window has a heating grid and a moisture sensor formed thereon for connection to a detector which automatically controls the heating. The sensor has an output terminal and another terminal connected to a heating conductor, the sensor being positioned outwardly of the heating grid with the area of the sensor including the output terminal lying in the heating zone. Advantageously the outer limit of the sensor is closely adjacent the outer limit of the heating zone. The output terminal is positioned between the outward limit of the sensor electrodes and the boundary heating conductor. A shield electrode connected to the heating conductor may be provided. The sensor may be located between a pair of heating conductors adjacent a heating grid collector with one electrode connected to the conductors. For deep windows, the sensor may be located in an offset branched section of a boundary heating conductor.

Abstract: A soil moisture sensing device employs a pair of indicator lamps to indicate whether the soil is too dry, too wet, or has the correct amount of moisture. The device need employ only one transistor or one Darlington transistor pair to control both indicators. Consequently, the device is more economical to manufacture than "prior art" soil moisture sensing devices that must use two or more transistors. In the invention, too dry soil is indicated by non-conduction of the transistor with neither indicator illuminated, adequately moist soil is indicated by partial conduction with one indicator illuminated, and too wet soil is indicated by full conduction with both indicators illuminated.

Abstract: A liquid sensor for sensing a level of liquid contained in a tank as well as the presence or absence of water remaining at the bottom of the tank is disclosed. The liquid sensor comprises a housing mounted at the bottom of the tank, a liquid level detecting element mounted on the housing, a pair of electrodes arranged at the bottom of the tank to detect water remaining at the bottom of the tank and an indicator operated in response to signals developed by the liquid level detecting element and the pair of electrodes.

Abstract: A plurality of water detectors are positioned under the water-impermeable membrane of a roof. In the event that the water-impermeable membrane is broken and the roof leaks, the general area of the leak can be determined.