Abstract: An improved alerting system and method of manufacture and assembly for boats that contacts boat owners at a remote location to pending danger of water rising within the boat and permits the boat owner to contact the system to determine the rate of water rising.

Abstract: Disclosed in a Rainfall Detection and Disable Control System which provides detection and a visual display of both a trace level and a variable accumulation level of natural rainfall. The dual interacting rainfall detection system provides a unique sprinkler system control function that disables sprinkler system watering both during and after a rain shower, based upon the amount of rainfall accumulation, and user selectable disable time periods. A short variable disable time period is initiated by the trace rainfall detection probe and a long variable time period is initiated by the accumulation rainfall detection probe. The trace rainfall detection probe provides the control function of preventing watering, at the onset of, and during a rain shower. The short disable time period of the trace detection function allows the next watering cycle to occur, if no significant rainfall accumulation is detected.

Abstract: A safety device which is responsive to excessive wave motion of a body of water includes a housing having a pivotable telescoping arm connected thereto. A pair of spaced apart probes are mounted on the end of the arm. The probes are connected to a control circuit located in the housing. The control circuit measures the electrical resistance between the two probes, which is normally an open circuit. In use, the arm is manipulated so as to position the probes a desired distance above the normal water level when no one is in the pool. Thus, the space separating the two probes is normally not bridged by water from the pool. When a person enters the pool, however, larger waves are created. These larger waves splash across the probes, bridging the space therebetween. As a result, the electrical resistance between the probes decreases. The control circuit is responsive to this change for generating an alarm. The safety device may also include a pressure responsive switch secured to a step of a ladder in the pool.

Abstract: An alarm system for sounding an audible warning whenever the water level within a sump pump enclosure exceeds the level which normally actuates the sump pump. The alarm system comprises an open electrical circuit including a battery, a battery-powered audible warning device and an elongate probe having closely-spaced contact members adjacent the tip thereof. The tip is suspended in the pump enclosure, above the pump-actuation level, and the warning device is activated whenever the water level rises above the pump-actuation level and immerses the contact members.

Abstract: A water level sensing probe which comprises a central electrode encircled by a tubular ceramic insulator which is held between an integral laterally projecting portion of the electrode, which forms a conductive tip, and a tubular metal mounting body which surrounds and is displaced from the electrode that passes through it. The ceramic insulator is taper locked within the conductive tip at one end and within the tubular metal mounting body at the other end.

Abstract: An automatic water replenishing system is designed for use with multiple dye vats used for tinting eyeglass lenses, but the broad principles of the invention could apply to other systems used for replenishing individual ones of plural vats or reservoirs with water or some other liquid. A rotary water distributor rotates about an arc when it is signaled by water level sensors that the water in a particular vat is low. As the rotary distributor reaches the low reservoir, the LED carried by the distributor actuates a photo transistor adjacent the particular reservoir that needs replenishing, causing the motor to stop and the water supply solenoid valve to be actuated, filling the reservoir until a brief period of time after the level sensor indicates a full condition to the central control system.

Abstract: An oil and water separator for separating oil from water collected in a bilge of a boat prior to discharging the water overboard. A reservoir is provided for receiving the mixture of oil and water from the bilge. The oil separates from the water and floats on top of the water. When only water is positioned between a pair of spaced electrical probes carried in the reservoir, such causes a drain valve to be opened to drain the water from the reservoir. As the water is drained from the reservoir, the oil floating on top of the water will come between the probes and close the valve, stopping the draining of water from the bottom of the reservoir. A mixture of oil and water is pumped from a tank carried in the bilge at an intermittent rate so that the mixture is allowed sufficient time to separate in the reservoir.

Abstract: A test tube holding a liquid specimen therein is arranged between a pair of electrodes arranged in an opposed relation. A conductive nozzle is inserted into a test tube. An oscillator is connected to one of these electrodes and a receiver is connected to the other electrode. A nozzle is connected to a zero potential level common to the oscillator and receiver. When the tip end of the nozzle is brought down into the level of the liquid specimen, there occurs a change in electrostatic capacity between the electrodes and hence a change in the level of a signal transmitted from the oscillator to the receiver. A determining device determines, based on the change in the level of the signal, whether or not the tip end of the nozzle is in contact with the liquid level.

Abstract: A liquid monitoring device includes means for detecting the presence of a liquid and means for giving an alarm when the liquid is detected. Preferably a temperature sensor is also provided and the temperature is displayed on an LCD. The temperature sensor is arranged to sense the ambient air temperature at a first sampling rate and then the liquid temperature, after the liquid has been detected by a detector, at a second, more frequent sampling rate. The components are housed in a casing which carries a pivotably mounted sucker for attachment to a wall or bath.

Abstract: A perishable fluid container assembly is disclosed as including a timing mechanism in conjunction with a coffee pot, wherein a visible indicator device is energized while the coffee within the pot remains fresh. When the coffee pot is filled with fresh coffee, the visible indicator device first becomes energized, and stays energized even though the coffee pot is temporarily tipped on its side for the dispensing of coffee. After the predetermined time duration has expired, the visible indicator device is de-energized to indicate that the character or freshness of the coffee has expired. Additionally if the coffee pot becomes empty, the visible indicator device becomes de-energized after a short time delay.

Abstract: A body fluid excretion volume measurement apparatus for medical application. The apparatus stores body fluid excreted from patients in a body fluid storage tank and measures the resistance value with a resistance sensor. The resistance value depends on the shape of the body fluid storage tank, and if the tank is columnar, the resistance value is monotonically increasing with respect to the depth of body fluid. The output of the resistance sensor is processed by a measurement part and electric measurement of the body fluid volume stored in the body fluid storage tank is performed automatically.

Abstract: An apparatus and method employing a liquid level detection conductance probe mounted in a container to sense resistive differences between the probe and container depending upon the presence or absence of liquid therebetween. A sensing circuit senses probe signal variations and stores a probe signal. A comparator compares the stored probe signal to current probe signals and switches means connected to the comparator depending upon the presence or absence of liquid between the probe and container. The sensing circuit has sufficient sensitivity to differentiate between liquid between the probe and container and foam or scale deposits therebetween.

Abstract: A control circuit for a sump pump or other pump that controls the liquid level in a vessel. The liquid is maintained between upper and lower levels defined by probes in the vessel. The probes are associated with comparators and connect with one comparator input. The upper limit comparator connects with the gate of an SCR which supplies current to the lower limit comparator and also to a relay which controls the on/off condition of the pump. The output of the lower limit comparator controls a switching transistor which is arranged in a series circuit with the SCR and relay coil. Once the SCR is conductive, it is latched in the conductive state until the transistor is made nonconductive by the lower limit comparator. In a sump pump application, latching of the SCR allows the pump to remain activated after the liquid level is reduced below the upper probe.

Abstract: A liquid level measuring and indicating system using a positive temperature coefficient wire as a sensor, a microprocessor based operating circuit, and an electronically controlled display device. With energy to operate the system being supplied by a battery, circuit includes energy conservation provisions.

Abstract: A liquid activated control switch for detecting the presence of an excessive accumulation of low ionic strength liquids in an air refrigeration system and for controlling the operation of the air refrigeration system based upon the detection of the accumulated liquid which includes first and second liquid detection probes. When the liquid detection probes detect an excessive accumulation of liquid, the air refrigeration system is disconnected. After the excessive accumulation of liquid has been removed, the air refrigeration system remains disconnected until the switch is reset. Alternative embodiments of the liquid activated control switch prevent sloshing liquid in the vicinity of the probes from rapidly turning the switch on and off, by providing varying degrees of sensitivity to accumulated liquid. Time delays are provided in turning off the air refrigeration system when liquid is detected by the probes, and in turning on the system when liquid is no longer detected.

Abstract: The apparatus comprises at least two oscillating rods which are secured spaced from each other to a diaphragm, the edge of which is connected to a screw-in piece. On the side of the diaphragm remote from the oscillating rods a clamping screw is fixedly connected to the diaphragm so that the clamping screw and diaphragm assume a position with respect to each other in which the axes of symmetry coincide. The clamping screw is surrounded by a stack of annular piezoelectric elements, electrode rings and insulating rings. The stack forms the excitation and receiving transducer of the apparatus. The stack-shaped excitation and receiving transducer is clamped and secured between the diaphragm and a hexagonal nut. The stack bears on pressure studs which are arranged between a metal ring terminating the stack and the diaphragm. The clamping force is chosen so that the diaphragm is simultaneously concavely prestressed.

Abstract: A water leakage detector is disclosed herein sensitive to the presence of moisture, having an elongated sensor strip comprising a pair of conductors separated by insulation. Each conductor includes an electrode coupling with a wire lead extending via a cable to an electrical plug. A circuit housing is provided having an audible alarm operably connected to an electrical socket adapted to detachably connect with the plug. A low voltage battery and auxiliary output socket are carried on the housing and connected with the alarm and the first mentioned socket whereby the presence of moisture across the pair of sensor conductors activates the alarm. A battery test pair of electrodes is provided to manually test battery condition.

Abstract: A capacitive liquid level sensor utilizes capacitive principles to sense the level of a liquid contained within a receptacle. As a liquid rises and falls in the container, the dielectric effect of the liquid changes the effective capacitance of a sensing capacitor which is detected by electronic circuitry coupled to the sensor. One plate of the sensor capacitor is a probe disposed within a receptacle while a grounded conductive portion of the receptacle is a second plate of the capacitor. The liquid within the receptacle acts as a dielectric between the plates.

Abstract: The invention is an improved level indicating and elevation indicating system using a hose containing fluid having a first and a second end, capable of being operated by a single person. An electronic method is used to indicate when a float at the first end of the hose is at, above, or below a reference. In the preferred embodiment, such indications are communicated through wires to three distinct lights at the second end of the hose, and a sight is used to determine accurately the position of a float at the second end. The preferred embodiment also includes a sleeve supporting the first end of the hose and a support for the sleeve. Also included are a vertical fixed rod for supporting the second end of the hose, a base for holding the fixed rod in virtually any position, and an adjustable rod (parallel to the fixed rod) for determining vertical offset distances. A pinching device, for slightly varying the volume of the hose, is also part of the preferred embodiment.

Abstract: A water level sensing probe having a probe body (24), a protective sleeve (28), and an external housing (26) is disclosed. The body contains a detector board (40) that partially protrudes from its bottom and a logic board (42) that partially protrudes from its top. The detector board senses the level of electrically conductive fluid and transmits an indication of that level to the logic board that controls the operation and partially processes the data in response to commands received through a cable (28). The detector board is protected by the protective sleeve (28) while the logic board is enclosed in the external housing (26). The probe is used by positioning on the bottom of a fluid containing tank or other vessel. Water at the bottom of the tank forms a bridging contact between a ground plane and a number of traces on the detector board proportional to the level of the water.

Abstract: The present invention provides a locator/monitor capable of locating a boring tool and monitoring the progress of the tool for control purposes. The locator/monitor may be used in expedited locating methodology and straightforward calibration techniques of the present invention. A durable and cost effective pitch sensor is also provided by the present invention. In addition, the present invention provides a slotted transmitter housing formed of an electrically conductive material, where the magnetic field generated by the transmitter is capable of penetrating to the surface.

Abstract: The electrostatic capacitance sensing circuit comprises a resonance circuit composed of an electrode capacitance formed by a substance to be measured and sandwiched between two opposing electrode plates and an inductance at least part of which is connected in parallel to the electrode capacitance; an active element (e.g. transistor) for constituting an oscillator in cooperation with the resonance circuit; and in particular a capacitor connected between the resonance circuit and the active element. Since a dc bias voltage of the active element is substantially not applied to the electrode plates, it is possible to prevent electrolytic corrosion of the electrode plates due to electromotive force generated between the electrode plates when ions are resolved into the substance to be measured and therefore the substance changes to an electrolytic solution.

Abstract: A liquid level sensing device for determining the level of a liquid in a liquid confining unit, methods of making and operating the device and a laundry machine using the device are provided, the device comprising a pair of electrode plates disposed in spaced apart relation so as to be adapted to be in a certain position relative to the confining unit and having opposed ends, an electrical circuit connected to the electrode plates for creating a voltage signal therefrom that varies in relation to the level of the liquid in the confining unit relative to the electrode plates, a control for determining the actual level of the liquid from the signal, and a third electrode plate disposed in spaced apart relation to the pair of electrode plates and being adapted to cooperate with one of the pair of electrode plates to provide a reference voltage signal to determine the electrolytic base of the liquid.

Abstract: An alarm system for use in a salt-brine tank of a water softener has a sensor including a stem member having a lower end received in the bed of salt within the salt-brine tank and an upper end projecting above the bed of salt. An spaced pair of electrodes are supported at the stem member upper end and are responsive to direct contact with a brine solution inside the tank for generating the signal indicative of an abnormal condition. An electronic circuit is coupled to the sensor for generating an alarm which includes two counters coupled to a clock circuit such that any alarm indicative of the abnormal condition is delayed for a predetermined period of time after the sensor signals the abnormal condition, and the alarm is generated as spaced, short bursts of sound, the spacing between the bursts of sound being greater than the duration of the bursts.

Abstract: The boat sinking warning device is hermetically sealed box, to be permanently installed in the bilge area of a boat, to give an audio frequency or radio frequency warning if a boat is leaking. It comprises two externally exposed conductive terminals, and an electronic circuit to sense the presence of water across these terminals and thereby continually sound an audio alarm or radiate a radio-frequency signal to a remote facility.

Abstract: A fluid status detection system includes a plurality of probes connected to a controller. The controller includes a microprocessor, a digital memory, relays, and progammed so that selected alarm and relay latching conditions may be stored, and alarms activated and relays latched according to the alarm and latching conditions. The microprocessor is programmed to provide an alarm acknowledgement signal upon the alarm being acknowledged. An operator may select one or more release conditions individually for each relay from a plurality of possible relay release conditions and store the conditions in the memory. The possible relay release conditions include: the condition that the probe signal indicates that the event that caused the alarm has cleared; the condition that the alarm acknowledgment signal has been provided; the condition that the probe signal indicates that the event that caused the alarm has cleared and the the alarm acknowledgment signal has been provided.

Abstract: A storage installation capable of storing a variety of materials includes a shielded level sensing device disposed entirely externally of the container. The sensing device includes an elongated strip of metal which is associated with shielding circuitry for electrostatic protection of the strip. The sensing metal strip serves as a capacitor component in an oscillator circuit which is arranged so that the electrostatic field emanating from the sensing strip will change oscillator amplitude in proportion to the level to be sensed of material in the container. Detected changes in amplitude of the oscillator circuit produce a DC level proportional to the level of the oscillator amplitude, which in turn may be processed to indicate the level of material within the storage container.

Abstract: A pressure-activated diaphragm valve which when installed in the main up-stream side of a pressurized line, responds to signals from a control unit to shut off the main supply line and at the same time, opens a drain port on the down-stream side of the valve. When used as a freeze protection system, the main water line is shut off and the drain port opened before the freeze point, thereby, eliminating water damage from frozen, broken pipes. The valve also is self-cleaning and has a magnetic plug to remove and keep metallic particles out of the control chamber and the control unit has automatic and manual modes.

Abstract: A probe which mounts in a liquid container has a conductance electrode containing a temperature sensor. A conductance control circuit is coupled to the probe to control an output relay in accordance with predetermined impedance conditions at the probe, and a temperature limit control circuit also controls the output relay in accordance with predetermined temperature conditions at the probe.

Abstract: A circuit for detecting hydrocarbons comprises an input circuit receptive of an input signal representative of the electron movement in an unknown sample to be detected for producing a first amplified signal and a signal processing circuit receptive of the first amplified signal from the input circuit for producing a first output signal when the input signal represents the presence of hydrocarbons. The input circuit comprises four transistors connected as common base amplifiers with the base of a first of the four transistors receptive of the input signal, the base of a second of the four transistors connected to the emitter of the first transistor, the base of a third of the four transistors connected to the emitter of the second transistor, the base of a fourth of the four transistors connected to the emitter of the third transistor to produce the first amplified signal at the collector of the fourth transistor and wherein for the first transistor 70<hfe.ltoreq.120, for the second transistor 150.ltoreq.

Abstract: A level sensor with an amplifier circuit includes one of the level detection resistor and the temperature compensation resistor as an input resistor or a grounding resistor to the negative input terminal of the operational amplifier, and includes the other resistor as a negative feedback resistor.

Abstract: A portable level sensing device includes an audible alarm and a visual alarm (preferably LEDs) for signalling when a predetermined level has been sensed by a capacitance proximity switch. The device is designed for use in tank cars, ships, barges, and tank trucks, and includes a graduated rod and a threaded coupling to allow one to quickly and easily set the capacitance proximity switch at the proper level in a tank. The device includes an weather-tight housing and is intrinsically safe for use in hazardous area classifications Class I, Division 1, Groups A, B, C, & D. The device can be coupled in a pressuretight manner to the tank to prevent the escape of fumes during use.

Abstract: A leak and liquid level detector includes a transistor as its main operating element with a pair of normally open base contacts connected to the transistor base. The transistor emitter is connected to ground and the transistor collector is connected to a suitable audio alarm, or alarm light or to a programmable logic controller. When a liquid leak bridges over the base contacts, a power circuit is closed across the contacts biasing the transistor and causing an electrical signal to flow from the collector to actuate the alarm, light or controller. The base contacts are linearly adjustable to sense various leak heights. The detector in one mode of use can be positioned horizontally to detect leaks and in a second mode of use is positioned vertically to detect a change in a liquid level in a tank, pipe column or the like.

Abstract: A temperature controller with an integral liquid level control contained within one unit. The unit consists of an electrical and heat conductive housing, which serves as a first electrode of the liquid level sensor. A metal clamp and a means to attach the housing to the liquid vessel is insulated from the housing and serves as a second electrode. The electrodes are connected in an electrical circuit such that when the electrodes are immersed within a conductive liquid the resistance between the electrodes is reduced and a current is allowed to flow. A temperature sensor, such as, a thermistor, RTD, or thermocouple, is contained within the housing. The housing conducts heat from the housing environment for radiation within the housing.

Abstract: The present invention is a liquid sensing device used for in determining the presence or absence of liquid in a container by the presence or absence of electrical current flow between two conductive probes. Moreover, the present invention prevents the false indication of liquid as can result from the presence of foam, or from bridging of the probes at the proximal ends thereof. A main body portion is formed of an electrically conductive material and has a probe channel extending therethrough. A non-conductive plug is inserted into the proximal end of the probe channel and provides for the retaining of a conductive probe that extends along the central axis of the probe channel. An end cap is secured to the distal end of the main body and covers the distal end of the probe channel for preventing foam access into the probe channel.

Abstract: An oil level sensor has a cylindrical hollow sensor body and an elongated inner electrode provided in the sensor body at a distance from the inner wall of the sensor body. The sensor body is made of conductive resin including carbon particles.The sensor body is electrically connected to the elongated inner electrode and to a control unit for indicating a shortage of the fluid. The control unit is a shielded wire comprising a lead wire connected with the elongated inner electrode and a wire shield connected with the cylindrical hollow sensor body. The elongated inner electrode has a flange at a base portion thereof so as to be firmly secured in the inner electrode guide and an insulator sleeve plugged into the cylindrical hollow sensor body, whereby the flange is held between the inner electrode guide and the insulator sleeve.

Abstract: A liquid level and composition sensor includes a first interdigitated capacitor mounted substantially vertically in a tank, and a second interdigitated capacitor mounted substantially horizontally in and near the bottom of the tank. An electronic processor is responsive to the value of capacitance of the first capacitor for producing a first voltage signal proportional to the level of the liquid in the tank and is responsive to the value of capacitance of the second capacitor for producing a second voltage signal having a voltage level corresponding to the composition or dielectric constant of the liquid. The processor also multiplies the first and second voltage signals together to produce a liquid level voltage output signal having a constant slope for voltage amplitude versus liquid level, regardless of the composition of the liquid in the tank.

Abstract: A method and an apparatus for determining the thickness of a layer of a first liquid above an interface formed by the first liquid and the second liquid underlying the first liquid in a subterranean formation. The apparatus includes an elongated metal rod having a sharpened distal end. An electrode is provided adjacent the sharpened distal end to indicate when the interface formed by the two liquids has been reached. A lengthwise running elongated slot is provided in the outer surface of the body of the metal rod and contains an indicator strip. The indicator strip is adapted to undergo a color change upon contact with the first liquid. By measuring the length of the indicator strip which has undergone a color change, the thickness of the layer of the first liquid can be determined.

Abstract: A liquid level sensing apparatus, including a bridge circuit sensitive to an element the impedance between a liquid sample and a pipette for providing a signal corresponding to the impedance, a phase detector for phase-detecting the output signal of the bridge circuit, a high-pass filter for differentiating the phase detection signal and a circuit for inhibiting the passage of a variation component of a signal from a band-pass filter and passing a liquid level signal component.

Abstract: A linear compensated capacitive fluid-level sensing device includes three capacitors. A measurement capacitor is positionable during use to receive a fluid. A compensation capacitor is submerged in the fluid so that the fluid fills the space between the electrodes. An offset capacitor has a capacitance equivalent to the capacitance of the measurement capacitor when only air exists between the measurement electrodes. Charge applied to each of the three capacitors is discharged to an associated differential amplifier through a respective switch when the capacitors are disconnected from a charging voltage supply. The offset amplifier generates an inverted output current that is applied to the discharge currents of the measurement and compensation amplifiers. The compensation amplifier output gates a frequency-controlled oscillator that in turn controls the switches.

Abstract: One electrode of the probe is its tubular outer sleeve (3), and the other is its central rod (4). The insulators (9,16) separating the two are attached rigidly to the central rod, whereby the outer sleeve may slide off the probe for cleaning and servicing purposes. The outer sleeve is held in place simply by friction from the O-ring seals (12,30). When the sleeve is removed, the central rod, insulators, etc., remain as a structurally complete sub-assembly. Electrical contact with the outer sleeve is made through an expandable canted coil spring (20), mounted on an insulator. The central rod is formed with a massive center section (7), for weighting the probe. The probe is supported on a graduated tape (36), in which are embedded the electrical leads (38) to the probe. The leads are securely attached and sealed in place by means of heat-shrinkable material (50), which is wrapped around the leads, heat-shrunk, and compressed into a pocket (27).

Abstract: An improved capacitance bridge type liquid level control system for use in refrigeration applications is disclosed which provides improved apparatus for sealing the probe in its mounting and for insulating same against the condenser reservoir stand pipe in which it is mounted. Improved sealing between the probe and probe body is accomplished through an annular PTFE seal which when compressed pushes inwardly to seal a tubular PTFE insulation against annular ridges in the side of the probe rod proper. The improved probe rod shape also maintains a proper stabilized axial alignment between the probe rod and the probe body.

Abstract: The occurrence of physical contact between a conductive probe and a surface of a liquid held in a container is detected as the probe is moved toward and eventually touches the liquid surface; a conductor is disposed on the other side of the container from the probe; an electrical signal is sent through the liquid between the conductive probe and the conductor, and the time when physical contact has occurred is determined based on when the resulting electrical signal which has passed through the liquid exceeds a threshold; and the threshold is determined based on the resulting electrical signal. In another aspect, the electrical signal is pulsed, and the resulting electrical signal is synchronously detected as the basis for determining when the physical contact has occurred.

Abstract: Provided is a fuel level detector for use in a fuel tank of an automobile or the like which can accurately detect a fuel level with a reduced power consumption exhibiting an improved reliability regardless of the ambient temperatures and the temperatures of liquid fuel in order to overcome the problems involved in a thermistor method and a metal wire method. A spontaneously heated sensing resistor having a high temperature resistance coefficient is formed on a substrate so as to detect a change in the resistance value due to cooling by heat of vaporization at a portion of the sensing resistor which is dipped in fuel as a differential output voltage. In order to prevent errors in the differential output voltage due to the correction of the ambient temperature in the fuel tank, a temperature compensating resistor is provided on the substrate.

Abstract: A circuit for operating a load in response to predetermined external conductivity conditions comprising a pair of sensing electrodes, a source of electrical energy connected to one of the electrodes, a load connected to the other of the electrodes, a controlled switch connected to the load, a first energy storage branch having a timing chracteristic and connected between the source and the other electrode, a second energy storage branch having a timing characteristic and connected across the combination of the load and a controlled switch, and a control operatively connected to the first and second branches and connected in controlling relation to the controlled switch so that when the electrodes are exposed to a first medium having a predetermined electrical conductivity energy builds up on first and second branches and the controlled switch is open and then a predetermined time after the electrodes are exposed to a second medium having a different electrical conductivity the controlled switch is closed and

Abstract: A control for a water distillation apparatus admits untreated feed water to the boiling tank in response to a demand for the production of distilled water and operates the heater to produce steam. Level probes in the boiling tank monitors the level of untreated water in the boiling tank and admits more feed water as necessary. When demand for production of distilled water has ceased, the heater is deenergized and the boiling tank is filled to dilute the residual water in the tank and lower its temperature prior to drainage to prevent damage to a plastic house drain. In a preferred embodiment, feed water is admitted to the boiling tank in large batches and the production of distilled water continues uninterrupted until the entire batch is distilled to conserve heat energy even if demand ceases during such batch distillation. A cleaning mode is provided to remove scale from the interior of the boiling tank with a simplified manual cleaning procedure.

Abstract: A non-intrusive fluid level detector including a single point capacitive sensor mounted on the outside surface of a receptacle such that capacitive principles can be utilized to sense the level of a liquid contained within the receptacle. The sensor assembly is disposed in a substantially fixed position on the exterior wall of the receptacle wherein the dielectric effect of the liquid changes the effective capacitance of the sensing capacitor as the liquid rises and falls within the receptacle. This change in effective capacitance is detected by electronic circuitry included in the detector device. In one embodiment, the fluid level detector is directly mounted to a completely non-conductive receptacle. In another embodiment, the fluid level detector is mounted to a non-conductive window which is an integral part of a receptacle fabricated out of a conductive material.

Abstract: A fluid detection system includes a central monitor, an overfill probe for detecting the approach of the overfill condition of a tank of liquid, and n other probes, where n is an integer greater than or equal to 1. The probes are connected to the monitor via electronic cables. The monitor communicates with the probes by producing probe identifier signals comprising integers starting with zero up to the number n. Each probe includes a signal receiving and sending means which compares the identifier signal sent by the monitor to a preset identifier number for that probe and sends a status signal indicative of the fluid status at that probe when it receives the identifier signal that is the same as the preset number. The overfill probe is set with the identifier zero. The monitor includes a timing circuit which determines a six second probe check cycle.

Abstract: A storage installation which is capable of storing a variety of materials, both conductive and non-conductive, includes a level sensing device disposed entirely externally of the container for the material such as to the exterior of the walls thereof. The sensing device includes an elongated strip of metal preferably copper or brass cut to the length of the container when arranged in a vertical direction therefor and applied to the exterior of the container by suitable adhesive material. The sensing element serves as a capacitor component in an oscillator circuit which is arranged whereby the electrostatic field emanating from the sensing strip will change the oscillator amplitude proportional to the level of the material in the container. The detected changes in amplitude in the oscillator circuit will produce a DC level proportional to the level of the oscillator amplitude. The DC level in turn will be processed by a remote indicator circuit to drive a readout meter, bar graph or digital unit.

Abstract: This invention relates to a method of annoucing a low level of the remaining liquid in a dropper. According to the present invention, two electrodes are attached to the outer surface of a dropper, and a pulse of a stable level is applied to one of these electrodes. The remaining quantity of the liquid in the dropper can be detected automatically with ease by utilizing the variations of the electrostatic capacity occurring between these two electrodes. An annunciator is activated when it receives a signal representative of a low level of the liquid in the dropper, to inform a nurse of the necessity of replacing the dropper.