Abstract: A fluid condition indicating system and method using visual and audible devices. The system includes a circuit having visual and audible indicators, a power supply, and a plurality of switches or sensors. A start switch is coupled to the power supply, the visual indicator, and the audible indicator, and an enable switch is responsive to an ignition signal. During engine starting, the circuit enables the visual indicator in response to a condition of the start switch and a low fluid sensor, and disables the audible indicator. The audible indicator is enabled in response to the condition of the enable switch after engine starting, and may include a transistor or an output of a controller such as a microprocessor. The system may be integrated into a single wiring harness that can be easily replaced or retrofit onto existing outdoor power equipment.

Abstract: A liquid level detecting apparatus resistant to the deterioration and corrosion thereof is provided while holding down an increase in the manufacturing cost thereof. This apparatus 1 has fixed electrodes 3 on which a sliding contact point 5 is slidingly moved in accordance with a fluctuation of a float, and a first resistor 4 connected to the fixed electrodes 3, the fixed electrodes 3 being made of at least silver (Ag), palladium (Pd) and a glass component, a weight ratio of the silver (Ag) to palladium (Pd) being not lower than 75 wt. % to not higher than 25 wt. %, a sliding portion 7 of the fixed electrodes 3 on which the sliding contact point 5 is slidingly moved being covered with second resistors 8 a resistance value of which is lower than that of the first resistor 4.

Abstract: An apparatus is disclosed for electronically and non-invasively sensing liquid level in a boiler or other liquid-containing vessel. The apparatus, comprising a sensor and sensor integrated circuit can be uniquely designed for external attachment to any commercially available gauge glass used for visually determining liquid level in a boiler and other liquid-containing vessels. The apparatus, which employs proximity level-sensing technology, is suitable for determining liquid level provided the liquid-containing boiler or vessel is metallic and the liquid is electrically conductive, for example water and other aqueous solutions. The apparatus can additionally comprise at least one, preferably two externally located electrical pushbutton switches, for example “water feed” and “test”, for manually adding water to the boiler and for testing the apparatus' proper working condition with a simulated low water condition, respectively.

Abstract: Devices and methods are disclosed for sensing the level of a fluid in a reservoir. The device comprises a generator for generating symmetrical pulses of electric potential, a ground generator in communication with the above generator, means for sensing resistance, and a latch circuit in communication with the above means for sensing resistance. In a method of the invention, a first electric potential is applied to an electrode within the reservoir. The first electric potential has a predetermined value and duration. The resistance of fluid within the reservoir is measured during application of the first electric potential. A second electric potential is applied to the electrode after the measurement for a period of time substantially equivalent to the duration of the first electric potential and of a value substantially equivalent to and opposite to the predetermined value of the first electric potential.

Abstract: A device for transmitting data between a sensor, in particular a capacitive level sensor, and an analyser unit, whereby the sensor and the analyser unit are physically separate from each other and a method for operating said device. The device and method permit the testing and/or adjusting and/or operation of a sensor, which is active. A first processor unit is dedicated to the sensor and a second processor unit is dedicated to the evaluating unit. Connecting lines are provided, by means of which both processor units exchange bi-directional data.

Abstract: A water activated release triggering mechanism is removably held to an exterior surface of a buckle housing and includes at least two probes and at least two batteries distributed between independent paths, for firing a squib. The distribution of batteries between independent paths precludes false firing from a single short with the body of the housing. The triggering mechanism is designed to be impervious to Electro Magnetic Interference (EMI) and to preclude false release in the presence of 20,000 volts of Electro Static Discharge (ESD). The triggering mechanism may be easily removed for servicing, replacement, or for upgrading. In one embodiment, the triggering mechanism causes the buckle to release in the same manner as during manual release.

Abstract: The invention relates to a device for determining and/or monitoring the level of a filling material in a container. According to the invention, an oscillatable unit is provided which is fastened to a membrane, whereby said oscillatable unit is mounted at the height of the predetermined level. An emitting-receiving unit is provided which, with a given emit frequency, causes the membrane and the oscillatable unit to oscillate, and which receives the oscillations of the oscillatable unit. A control/evaluation unit is provided, which identifies once the predetermined level is obtained upon a given change in frequency or which, with the aid of the oscillation frequency of the oscillatable unit, determines the density of the filling material.

Abstract: A low-water cut-off system [A] determines if fluid [W] within a boiler [16] or other enclosure drops below a predetermined level within the enclosure. A signal generator introduces a signal into the enclosure so that the signal is present for sensing at the predetermined level, where a probe [14] is provided for sensing the signal if present as occurs if the water is at the predetermined level. A control [18], which includes a microcontroller [25], is responsive to the probe for providing a control function in response to whether the signal is so sensed by the probe, and so to determine if water has dropped below the predetermined level. The function may be causing alarm signalling or boiler heating cut-off. Self-test and time delay features are also included. Provision is made so that the control compensates for variation in electrical conductivity of the water through which the probe signal is sent.

Abstract: A device for sensing a level of a fluid, the device including a microcontroller and a probe coupled to the microcontroller. The microcontroller applies a given DC potential to the probe for a first period of time, measures a voltage associated with the level of the fluid to be sensed after the first period of time, and applies a reference DC potential to the probe for a second period of time.

Abstract: A battery powered water leak detector and audible alarm are held on a credit card sized plastic board that has sufficient unobstructed area for visible messages, such as advertising, to be printed of otherwise affixed thereon.

Abstract: A capacitive gauge, suitable for measuring a fluid level in a container, includes upper and lower capacitive elements. Also provided is a control unit for calculating the fluid level in the container based on the capacitance of the upper and lower capacitors and a dielectric constant of the fluid in the container. The control unit also includes functionality for determining and storing the dielectric constant of the fluid in the container. The dielectric constant of the fluid is determined by first verifying whether the lower capacitive element is completely submerged based on a comparison of a measured capacitance of the upper capacitor to a reference capacitance of the upper capacitor. If the lower capacitor is verified to be submerged, then the dielectric constant of the fluid is calculated based on a measured capacitance of the lower capacitor.

Abstract: A tape-drive condensation sensor includes a probe with first and second spaced-apart electrodes that define a passage for air flow within a pneumatic conduit. A voltage source is coupled between the electrodes and the voltage of the source and the spacing between the electrodes are adapted to pass a current when a drop of condensation forms between the electrodes. An alarm circuit is activated by the flow of current, the alarm being adapted to signal an event of discernible condensation.

Abstract: An ultrasonic liquid level sensor instrument that combines a continuous transmitter that transmits though the air for measuring the level of liquid in a vessel on a continuous basis and a point level sensor that sets a high level alarm. The continuous level transmitter/receiver provides a continuous measurement of the liquid level in the vessel and the point level sensor is used for sensing an overflow, or high level condition in the vessel, as well as failure of the continuous transmitter/receiver. The instrument includes a sensor fixture that holds both the continuous air transmitter/receiver transducer and the point level sensor. The fixture is mounted in a single hole in the wall of a tank or a vessel in which the liquid level is being monitored. Each of the continuous level transmitter/receiver and point level sections of the instrument has a self check capability.

Abstract: The moisture sensor and indicator for a wet pickup vacuum cleaner, more particularly a wet extraction type carpet cleaner, is positioned in the suction duct to sense when water droplets or moisture is traveling through the suction duct. An indicator is activated to indicate to the operator that water is being extracted from the carpet. The sensor may alternatively be located in the bottom of the floor-engaging portion where it contracts the floor. When the degree of moisture in the carpet exceeds a predetermined threshold an indicator is activated to indicate to the operator that the floor is still wet and to continue extracting moisture from the floor. Alternatively, the moisture sensor can be used as a safety device on a dry pickup vacuum cleaner. When moisture is detected within the suction duct, the motor-fan assembly of the dry pickup vacuum cleaner is disabled to prevent a potentially hazardous condition.

Abstract: A capacitive fill level measurement device with a fill level sensor having a plurality of sensor fields, electrical wires for electrically connecting the plurality of sensor fields to a multipole side of a selector switch, and a power supply and evaluation circuit electrically connected to a monopole side of the selector switch. The capacitive fill level measurement device can be made with simple production technology and thus economically for a host of different applications using a matrix of printed conductors which extend vertically and horizontally such that each horizontally extending printed conductor on one side is connected to one sensor field and on the other side connected to a vertically extending printed conductor. Each horizontally extending printed conductor is connected with a respective vertically extending printed conductor to form an electrical line or a part of an electrical line.

Abstract: A sensing assembly senses a level of a liquid in a reservoir. The sensing assembly includes a first input port for receiving a first input voltage signal. The sensing assembly also includes a second input port for receiving a second input voltage signal. An excitation circuit is electrically connected to the first and second input ports for receiving the first and second input voltage signals and for generating a first excitation signal and a second excitation signal. A receiving circuit is disposed adjacent the excitation circuit and defines a variable capacitance with the excitation circuit. The receiving circuit produces an output voltage variable with the level of the liquid in the reservoir due to capacitance changes between the excitation circuit and the receiving circuit. The receiving circuit includes a first receiving electrode extending through a sine wave form and a second receiving electrode extending through a cosine wave form.

Abstract: A fluid sensor probe such as a temperature probe uses heat shrink tubing to seal and provide strain relief at a proximal end of the probe. The heat shrink tubing uses a layer of hot melt adhesive along its inside surface to form a strong bond and hermietic seal. The heat shrink tubing is applied as an inner tubing around circuit wires extending into the probe and as an outer tubing around the inner tubing and around the proximal end of the probe housing. Together the inner tubing and the outer tubing can hermetically seal a substantial gap between the probe housing and the circuit wires. In a fast response probe, prior to closing the distal end of the probe housing with an end wall, openings are punched in a side wall of the probe housing against a mandrel. The openings permit fluid flow to contact the sensing element within the probe housing. Heat shrink tubing can be used to seal the circuit wires and prevent leakage.

Abstract: A recovery device (1) includes a container (11) for recovering pure solvent (10) A measuring device (12) includes a capacitive detector (13) which is provided to signal if the container (11) is not empty nor substantially empty when one tries to start operation of the recovering pure solvent (10).

Abstract: The moisture sensor and indicator for a wet pickup vacuum cleaner, more particularly a wet extraction type carpet cleaner, is positioned in the suction duct to sense when water droplets or moisture is traveling through the suction duct. An indicator is activated to indicate to the operator that water is being extracted from the carpet. The sensor may alternatively be located in the bottom of the floor-engaging portion where it contracts the floor. When the degree of moisture in the carpet exceeds a predetermined threshold an indicator is activated to indicate to the operator that the floor is still wet and to continue extracting moisture from the floor. Alternatively, the moisture sensor can be used as a safety device on a dry pickup vacuum cleaner. When moisture is detected within the suction duct, the motor-fan assembly of the dry pickup vacuum cleaner is disabled to prevent a potentially hazardous condition.

Abstract: A control circuit for a plumbing device that has a drain line and a water supply line includes a water sensor generating a potential overflow level signal in response to the water level in the plumbing device caused from a restricted drain line, an electrically controlled valve coupled to the drain line, and a controller coupled to the water sensor and the valve. The controller closes the valve in response to the potential overflow level signal.

Abstract: A capacitive gauge, suitable for measuring a fluid level in a container, includes upper and lower capacitive elements. Also provided is a control unit for calculating the fluid level in the container based on the capacitance of the upper and lower capacitors and a dielectric constant of the fluid in the container. The control unit also includes functionality for determining and storing the dielectric constant of the fluid in the container. The dielectric constant of the fluid is determined by first verifying whether the lower capacitive element is completely submerged based on a comparison of a measured capacitance of the upper capacitor to a reference capacitance of the upper capacitor. If the lower capacitor is verified to be submerged, then the dielectric constant of the fluid is calculated based on a measured capacitance of the lower capacitor.

Abstract: A non-contact capacitance sensor having a base and an array disposed on the base is provided. The array has a first electrode and a second electrode disposed opposite one another so that the array senses a change in capacitance between the first and second electrodes.

Abstract: An interceptor for removing grease from an effluent stream containing grease and water may be queried remotely to check it status. An output signal indicative of the amount of grease is transmitted over a telephone line to a telephone or computer or other remote station, or wirelessly to a remote receiver. The status is preferably also indicated locally with visual and/or audible signals. The grease depth level sensor is preferably a capacitive level sensor operative to sense the amount of water in the body of effluent thereby to determine the amount of grease in the body of effluent. The interceptor may include electric circuitry for effecting manual or automatic calibration of the sensor. The sensor may be adapted to be retrofitted to an existing tank made from either metal or plastic.

Abstract: A capacitive liquid level sensor provides for a reliable and inexpensive means to measure fluid height. The capacitance measured at a sensor is interpreted by a control unit, which relays information regarding the liquid level to a display unit visible to the driver of the motor vehicle. In one embodiment, the sensor consists of two parallel electrode strips of a conductive material supported along their respective lengths by a substrate of an insulated material. The strips and the exposed side of the substrate are coated with a low conductivity porous material. The strips are connected to a control unit by a pair of electrical leads. When the sensor is immersed in a liquid, the control unit measures capacitance between the two strips and calculates the actual liquid height, based on the known dielectric constant of the liquid and the gas above it.

Abstract: A sensor for use in determining a level of a medium or detecting an object includes a plurality of spaced-apart electrically conductive members disposed on a nonconductive support. Each of the conductive members are connected to an astable multivibrator for selectively generating a first plurality of signals each having a frequency based on a capacitive value due to a respective conductive member, an at least one ground member, and at least one of an absence of the medium and a presence of the medium. A microcontroller enables determining the level of the medium or detection of the object based on the frequencies of the first plurality of generated signals. The microcontroller may be configured for compensating for buildup of a material on the sensor to enhance the accuracy of the sensor. Self-correcting features and safety features employed in the sensor are also disclosed.

Abstract: A low-water cut-off system [A] determines if fluid [W] within a boiler or other enclosure drops below a predetermined level within the enclosure. A signal generator introduces a signal into the enclosure so that the signal is present for sensing at the predetermined level, where a probe is provided for sensing the signal if present as occurs if the water is at the predetermined level. A control, which includes a microcontroller, is responsive to the probe for providing a control function in response to whether the signal is so sensed by the probe, and so to determine if water has dropped below the predetermined level. The function may be causing alarm signalling or boiler heating cut-off. Self-test and time delay features are also included. Provision is made so that the control compensates for variation in electrical conductivity of the water through which the probe signal is sent, including circuitry to adjust for a wide range of possible purity levels.

Abstract: A system and method for detecting parallel marketing of an item, include forming at least one of a coating and a code on the item, interrogating the at least one of the coating and said code, and determining from the interrogating whether the item has been transferred from an authorized merchant to an unauthorized merchant.

Abstract: A method and a system for detecting the level of fluid in a container is provided. The level meter includes first, second and third generally parallel probes being positioned within the container. The first probe includes a first portion that is at least partially covered by an insulating material, and a second generally exposed end. The second probe is generally free of the insulating material and the third probe provides an electrical ground. An electronic unit is operable to measure electrical characteristics of the first and second probes to determine an amount of the second probe which is exposed to a fluid within the container.

Abstract: A liquid level sensor apparatus and a method of using thereof for determining the level of a conductive liquid held within a container, wherein the container is subject to the accumulation of residue as a consequence of the conductive liquid contained therein. The liquid level sensor includes a sensor part which has a voltage; a ground connection having an electrical polarity; a circumferential ring having a bias voltage opposite in polarity to the ground connection and a voltage corresponding to that of the sensor attached around the sensor; a float which is buoyant on the conductive liquid; and a conductive tip attached to the top of the float, the conductive tip being conductive with the sensor end when in at least one predetermined position.

Abstract: A level sensor mechanism for detecting liquid levels in storage tanks. A conduit is provided having an upper portion and a lower portion. The conduit may be adapted to receive a cable therein, may be substantially rigid and adapted to resist deflection. A sensor assembly body is provided and adapted to locate a level sensor therein. The sensor assembly body may be located in fixed relation to said conduit, and may be rigidly composed and adapted to resist deflection. A coupling member may be secured to said lower portion of said conduit, said coupling member fixedly securing said conduit to said sensor assembly body, said sensor assembly body being secured on said offset portion of said coupling member. The level sensor mechanism may thereby resist or eliminate deflection through the construction of the conduit, coupling member and sensor assembly body.

Abstract: A probe assembly for monitoring the water level in boilers with an electric immersion resistor heater, of the type that comprises at least one sensor element to be arranged inside a hollow body which is in turn associated and partially inserted in the boiler. The hollow body has, on the portion arranged outside the boiler, a plug which axially supports the sensor element; the end of the sensor element arranged at the plug is connected, when the plug is installed, by way of at least one electrical contact, to an electrical power supply cable, whose contact end is arranged at the portion of hollow body that is arranged outside the boiler.

Abstract: The present invention provides an automatic monitor for use in a tank with a water soluble softening agent. The monitor includes a signal emitter that produces a signal capable of being detected by an array of signal-detecting sensors. The sensors are displaced generally vertically in the brine tank from the minimum depth of the softening agent to the maximum depth of the softening agent. An output is produced in response to said signal. The monitor also includes an electronic device for receiving and interpreting the output and determining if a low softening agent condition is present as the supply of the softening agent is depleted. An indicator warns when a low softening agent condition is present. Preferably, the sensors are linearly spaced within the tank.

Abstract: A water detection device and alarm. The water detection device includes protruding electrodes above and below the device which detect water on a surface below the device, and water dripping from above the device. The electrodes are rod-shaped, and can penetrate a material to detect moisture in subsurface regions of the material. The device has a lifting ring, and may be placed in difficult to access positions by means of the lifting ring. A deflector cone directs water from above the device into a splash ring. When water or moisture completes a circuit between two of the electrodes, an alarm enunciator signals the presence of water.

Abstract: A water feeder controller for a boiler monitors a low water cutoff sensor in a boiler and uses a feed timer to feed water to the boiler for a predetermined feed period of time. The feed timer brings the water level in the boiler well above the low water cutoff sensor. The feed timer supplies water to the boiler only if the low water cutoff sensor continues to indicate a low water level for a delay period of time measured by a delay timer. A resettable display indicates the quantity of water supplied by the water feeder to the boiler based on a feed counter incremented during water feeding. A manual feed button allows water to be manually fed to the boiler. The quantity of water manually supplied to the boiler is also shown on the display. The feed timer and delay timer are preferably implemented in software in a microcontroller in the water feeder controller. A lockout loop in the software prevents overfeeding of water to the boiler in the event of a failure of the low water cutoff sensor.

Abstract: A beverage dispensing apparatus includes a dispensing device, at least one valve that distributes a diluent, a concentrate pump that distributes concentrate, a support structure that supports the foregoing components, and exterior cladding attached to the support structure. The exterior cladding provides the appearance of a real leaf brewer. The diluent valve and concentrate pump distribute the diluent and concentrate into the dispensing device to form a mixture to be dispensed therefrom. The diluent can be hot water and the apparatus further includes an air ejector device for eliminating air bubbles from the hot water prior to mixing. In addition, an improved sensor can accurately determine when the supply of concentrate is depleted.

Abstract: A water detection system for detecting water and activating an alarm is provided. The water detection system includes an alarm relay and a water sensor. The water sensor includes a solid state switching and amplifying circuit for detecting low levels of current flow and amplifying the signal to activate the alarm relay. In one embodiment, the water detection system further includes an alarm panel, including visual and audible alarms activated by the alarm relay. In one embodiment, the water detection system includes multiple water sensors for providing zone protection. In one embodiment, the alarm relay is configured to shut-down the device causing the presence of water. A method for implementation of the water detection system is also provided.

Abstract: A flood prevention system includes a double-latching solenoid valve that shuts off a water supply line in response to a moisture sensor detecting a leak in a plumbing system. The double-latching feature provides the solenoid's plunger with two positions of equilibrium. This minimizes electrical power consumption so that the flood prevention system can be battery operated. To minimize a buildup of hard water deposits, the valve includes a flexible diaphragm and is cycled periodically regardless of whether flooding occurs. The sensor includes multiple methods of mounting to a floor.

Abstract: A safe and reliable aircraft fuel gauging system which eliminates the need for electrical wiring to transmit electrical signals into and out of the fuel tank of an aircraft. The fuel gauging system utilizes at least one light source to generate input light signals which are delivered to a plurality of probes multiplexed on a fiber optic element. The same, or a separate, fiber optic element transmits the probes' output light signals to a light detector located externally of the fuel tank. Each probe includes a photoelectric conversion device, an LC resonant circuit, and a magnetooptic device for generating the responsive output light signal to the input light signal. Based on the output signal form the probes, the light detector determines the level of fuel in the tank.

Abstract: A liquid level sensor includes a housing with circuitry provided therein. An inner and outer tube extend from the housing. The inner tube is positioned within a hollow center of the outer tube to form a coaxial configuration. A slot extends through the wall of the outer tube into the hollow center of the outer tube. The slot extends essentially the entire length of the outer tube. The circuitry, outer tube, and inner tube form a capacitive circuit to measure liquid. The slot allows the liquid to flow more easily into the hollow center of the outer tube and between the inner tube and outer tube to allow the sensor to provide accurate measurements with many types of fluids. The circuitry generates a pulse width modular output which is sent to a gauge to provide a visual representation of the level of the fluid in the container.

Abstract: An improved boiler water-level controller. According to one aspect of the present invention, a positive blowdown signal is presented to indicate to the operator that the alarm probe is in steam; performing blowdown until this indicator turns on helps ensure that the alarm probe is working properly. According to another aspect of the present invention, the controller uses a novel methodology of sensing water level using conductivity probes. An embodiment of this methodology uses the charging and discharging of a capacitor through a resistive value to sense the presence of water.

Abstract: The invention is system and method for detecting a leak and operating an existing valve in response to the detected leak. In this regard, a receiving unit may be installed on an existing shutoff valve. The valve may control the flow of a fluid into a site. A transmitting unit may be installed in the vicinity of an appliance receiving the fluid. The transmitting unit may include a detector capable of detecting the fluid. In response to the detector detecting the fluid, the transmitting unit may transmit a signal including a unique 32 bit code. A receiver within the receiving unit may be capable of receiving the signal. Additionally, a PIC microprocessor within the receiving unit may be configured to receive the signal from the receiver and determine if the signal contains the code. In response to determining the signal contains the code, the PIC may control a motor to operate (e.g., turn off) the valve. The motor may be configured for attachment to the valve via a coupler.

Abstract: A device is for sensing and alarming absence of water in a home machine for manufacturing soybean milk, watery bean curd, and bean curd, which allows the home manufacturing machine to be operated only when the home manufacturing machine contains water; so as to prevent the machine from being operated by a user without water, thereby preventing the machine from getting damaged. The apparatus includes a plurality of components installed in a body. The device includes a ground electrode and a signal electrode electrically connected to two selected in the plurality of the components, respectively; a resistor connected to the signal electrode; a switching transistor connected to the resistor; a controller connected to the switching transistor for outputting a control signal for an alarm when the absence of the water is sensed; a resistor connected to the controller; a switching transistor connected to the resistor; and a buzzer is connected to the switching transistor.

Abstract: A fault detection circuit in a boiler-water level system includes a dual-frequency signal generator which develops two AC components with no associated DC component. The two frequencies are mixed and sent through an impedance matching circuit to match the impedance of the signal generating portion of the system with the impedance of the boiler water under measurement. The impedance-matched signal is then directed to two legs, one leg directed through one of a plurality of electrode probes and then to a first filter circuit, and the other leg is directed a second set of filters. In combination, the filters pass either the higher or the lower of the two frequencies to determine an open or short condition in the level sensing circuitry, as well as a steam vs. water condition.

Abstract: An electronic control for the operation of a beverage dispenser of the refrigerated ice bank type is shown. The control provides for reliable determinations of when ice production is needed and when it is not needed. A microprocessor receives information from an ice bank probe and from a temperature probe located within the ice bank. Data collected by the microprocessor from both the ice bank probe and the temperature probe is used to determine if the ice bank is either insufficient in size and should be increased or is of sufficient size such that the compressor can be turned off. A carbonator level probe is also shown and connected to the microprocessor. The microprocessor is programmed whereby the carbonator probes are sampled in a manner to accurately determine the level of water in the carbonator and therefore the need for turning on or turning off any water pump connected thereto.

Abstract: A device for determining and/or monitoring the level of a medium in a container or for ascertaining the density of a medium in the container embodied as a vibration detector. According to the invention the vibration detector still functions reliably even under extreme process conditions and upon abrupt changes in process conditions. The vibration detector has a tubular inner part provided, which is dimensioned such that it is positioned between the housing wall and a drive/receiving unit, and that the tubular inner part is connected to the housing or to the diaphragm.

Abstract: A fluid level sensing systems including a resistive element having an upper end portion disposed in an upper portion of a container and a lower end portion disposed in a lower portion of the container. The resistance of the resistive element varies between the upper and the lower portions of the container. An at least partially conductive strip having substantially the same length as the resistive element is disposed in the container generally parallel thereto and at approximately the same level in the container as the resistive element. An input signal source is coupled to the resistive element by a series resistor.

Abstract: The invention relates to a device for determining the level (F) of a medium (3) in a container (2) using a capacitive sensor (4). A voltage source which subjects the sensor (4) to a measuring frequency (fM) is provided, as is a measuring/evaluating circuit (6) which establishes the measured capacitance (CM), compares this to a predetermined capacitance value and provides the information concerning the level (F) of the medium (3) in the container (2). The aim of the invention is to increase the measuring sensitivity of a capacitive sensor (4) without increasing the sensitivity of the sensor to interfering signals. To this end, the measuring/evaluating circuit (6) has at least one inductance (L) which together with the measured capacitance (CM), forms a resonant circuit (7).

Abstract: A liquid level sensor for conductive liquids having a bias ring to prevent false “full” indications. The sensor is an inexpensive conductive probe that can be installed in any tank or container used to contain a conductive liquid. The build up of residue such as sludge on the inside of the container wall and probe pieces can cause a short between the probe and ground. This situation will result in falsely showing that the level of the liquid being measured is at least at the minimum predetermined requirement even though the actual level may be far less than that amount. The bias ring is a metal ring that is placed around the insulating base of the sensing probe between the probe tip and the top inside of the tank. The probe is then given a charge (positive for negative ground systems) which interrupts the current path between the sensing tip of the probe and ground via the conducting residue. Consequently, the sensor will read correctly despite the conductive residue that may be present.

Abstract: The present invention relates to a measuring device at recovery devices (1). The recovery device (1) comprises a container (11) for pure solvent (10). The measuring device (12) includes a capacitive detector (13) which is provided to signal if the container (11) is not empty nor substantially emtpy when one tries to start operation of the recovery device (1) for recovering pure solvent (10).

Abstract: Disclosed is a device for sensing and alarming absence of water in a home machine for manufacturing soybean milk, watery bean curd, and bean curd, which allows the home manufacturing machine to be operated only when the home manufacturing machine contains water, so as to prevent the machine from being operated by a user without water, thereby preventing the machine from getting damaged. The apparatus includes a plurality of components installed in a body. The device includes: a ground electrode and a signal electrode electrically connected to two selected in the plurality of the components, respectively; a resistor connected to the signal electrode; a switching transistor connected to the resistor; a controller connected to the switching transistor for outputting a control signal for an alarm when the absence of the water is sensed; a resistor connected to the controller; a switching transistor connected to the resistor; and a buzzer connected to the switching transistor.