Abstract: A monitoring system includes one or more monitoring devices, positioned in sewer manholes, storm drains, etc., and a remote monitoring station that communicates wirelessly therewith. The monitoring device may be an integrated unit, including sensors, a two-way telemetry unit, a power supply, a processor, and supporting hardware, all located in an enclosed, waterproof housing. The monitoring device is placed within a manhole cavity to obtain depth (e.g., water level) measurements and report the measurements back to the remote monitoring station, which analyzes the data and responds to alert messages when a dangerous water level is detected. The sample and reporting rates of the device, as well as the water level threshold values, may be remotely programmable via commands transmitted from the remote monitoring station. An additional sensor may monitor the manhole cover for security purposes.

Abstract: An apparatus for determining and/or monitoring at least one process variable of a medium in a container. The apparatus has at least one mechanically oscillatable unit unit which produces a measurement signal at least dependent on the process variable. It also has at least one electronic unit which evaluates the measurement signal, and at least one function test unit associated with the electronics unit. The measurement signal passes through the electronics unit on at least one processing path, and the function text unit operates on the processing path during a function test in such a manner that a test measurement signal results from the measurement signal received by the electronics unit. The test measurement signal corresponds essentially to the measurement signal, which occurs for a predetermined value of the process variable.

Abstract: A radar level gauge system for determining the filling level of a filling material in a tank is disclosed. The system comprises a transmitter for transmitting measuring signals towards the surface of the filling material; a receiver for receiving echo signals from the tank; processing circuitry for determining the filling level of the tank based on said echo signal and adapted to compare said determined filling level with at least one preset threshold value and to produce an alarm signal in dependence of said threshold value; and a storage means for storing the preset threshold value, wherein said threshold value in said storage means is replaceable and/or adjustable. The alarm signal could indicate high level and/or overfill. The possibility of adjusting/replacing the threshold values enables adjustment of the alarm levels when the system is already installed. A corresponding method of operation is also disclosed.

Abstract: A wireless (e.g., radio) system and method for automatic water level maintenance of, e.g., a swimming pool utilizing capacitive liquid level sensing. A reference electrode allows water level sensing independent of the water chemistry or temperature. Capacitive electrodes having areas larger than the reference electrode sense various liquid levels when the liquid covers an area of any sensing electrode equal to the area of the reference electrode. Averaging is incorporated to filter out effects of wind or other disturbances. Upon sensing a given condition, the transmitter transmits a sensed condition to a remote receiver for control of valves and pumps for changing the water level in the pool. The receiver includes safety timers for filling and emptying to protect against equipment failure or communications faults. User selectable identification allows identical such radio systems to operate within proximity to each other. Power saving features are used to extend battery life.

Abstract: A single pump control unit can be coupled to first and second float switches and a pump for purposes of removing fluid from a region such as a sump. A supplemental set of contacts can be provided to couple an alarm indicating signal to a remote alarm. An alarm state can also be transmitted wirelessly.

Abstract: An apparatus for detecting a predefined fill level of a medium in a container having a lid by means of a conductive measuring system, which has at least two measuring electrodes extending into the container. A measurement current flowing between the two measuring electrodes is used to detect the reaching of the predefined fill level. The apparatus makes possible a differentiated detection of accretions on the lid of the container. According to one variant of the invention this is achieved by providing a compensation electrode, which is arranged such that the degree of fouling in the region of the lid of the container is determined on the basis of a current flowing between one of the measuring electrodes and the compensation electrode, caused by conductive accretions in the lid of the container.

Abstract: A system and method of verifying the installation and data path used by a tank level monitor is provided. Once an installer completes the installation of the tank level monitor, the monitor is activated. The monitor performs a self test and transmits information to a data center. Preferably, the transmission is via a cellular communication network. Once the data center receives the information from the newly installed tank level monitor, the data center generates a text based message that is sent to the installer to verify that the installation was successful. The message from the data center is preferably an email message that can be delivered to a wireless messaging device held by the installer. The generation and transmission of the verification message should be approximately immediate, and certainly within five minutes to provide rapid feed back to the installer.

Abstract: A fluid flow indication apparatus is provided for monitoring and giving an indication of fluid flow.

Abstract: A system for monitoring a level of product in a tank to detect one of a delivery and a drain operation is provided. The system comprises a monitor and a data center. The monitor is operably coupled to the tank and adapted to detect the level of product in the tank at a first rate and at a second rate. The data center is in communication with the monitor and adapted to receive a user inputtable threshold level of change. The monitor detects the level of product in the tank at the first rate until the threshold level of change is detected. Thereafter, the monitor detects the level of product in the tank at the second rate. The data center generates an alarm signal to indicate that one of the delivery and the drain has occurred.

Abstract: A detection apparatus for use in a vessel for measuring a fluid includes a tubular connected to a housing containing sensors, wherein the housing includes a top, a bottom, and a hole disposed in the top of the housing. The housing containing sensors includes an outer surface and a sloped inner surface sloping from the outer surface toward a central axis of the housing and intersecting with the hole. In one embodiment, two or more housing containing sensors can be included with detection apparatus. A pressure sensor, having a diaphragm flush mounted in the sloped inner surface, can be disposed in the hole. Signaling device can be disposed in the hole for communications between the sensors and a processor. The processor receives data from the sensors and converts the data to values for transmission to an auxiliary device.

Abstract: System for indicating when a tank is full. The system includes a signal and control box. A container is connected to the tank. The container has a base, a float, an upper portion, and a lower portion. An orifice is arranged at the upper portion of the container. The float has an electrical contact connected to the signal and control box. The base of the container is arranged one of above a maximum filling level of the tank and substantially at the same level as the maximum filling level of the tank. A communication conduit is connected to each of the base of the container and an area of the tank which is in proximity to an upper portion of the tank. The system generates at least one warning signal after the tank is completely filled and when the container is partially filled by the communication conduit. This Abstract is not intended to define the invention disclosed in the specification, nor intended to limit the scope of the invention in any way.

Abstract: A multiplexing system is provided for a plurality of sensors disposed in a tank containing a potentially explosive environment and excited from a common excitation circuit outside of the tank through a corresponding plurality of signal lines that penetrate the tank. The multiplexing system comprises: a multiplexer switch for each sensor, each multiplexer switch disposed outside of the tank in series with the corresponding signal line between the common excitation circuit and the corresponding sensor in the tank.

Abstract: A temperature and pressure measuring circuit is provided. The circuit comprises an uncompensated pressure transducer, an analog-to-digital converter, a reference resistive device, and first and second switches. The transducer has variable resistive devices between first, second, third, and fourth bridge nodes. The analog-to-digital converter has first and second reference inputs and first and second differential inputs. When the first switch couples the first differential input and the third bridge node and the second switch couples the second differential input and a ground, a bridge voltage is measurable and a bridge resistance is ratiometrically determinable. The bridge resistance is employed to calculate a temperature. When the first switch couples the first differential input and the first bridge node and the second switch couples the second differential input and the second bridge node, a differential voltage is measurable. The differential voltage is employed to calculate a pressure.

Abstract: A wastewater fluid level sensing and control system is provided. The system comprises a control panel, a reservoir, at least one pump and a fluid level sensing device. The control panel comprises a housing and user interface input and output devices for use with configuring the operation of the control panel. The control panel may be configured to turn on one or more of the pumps to lower the level of fluid in the reservoir. When the level is above a selectable level, the control panel is operative to cause at least one alarm signal to be output. The control panel may include a touch sensor pad mounted to an inner wall of the housing. Changes in capacitance in the pad as a result of a hand being placed adjacent the sensor on the outside of the housing is operative to cause the control panel to silence the alarm.

Abstract: In this compactor service and monitoring system, compactor fullness and other critical parameters are monitored by an on-site processor. Compactor fullness is monitored using a pressure sensor capable of measuring hydraulic fluid system pressure for a compactor ram during a compactor compaction cycle. The processor generates a message indicating the compactor is full when the pressure is at least equal to a preset pressure for a preset time during a compaction cycle. Messages are sent via a wireless transmitter to a receiver that converts these messages into internet messages and directs them to a computer server database system. This system creates a work order in response to the message and sends the work order to a service provider via email. The email contains a link back to the database system web-site for tracking services provided by the recipient.

Abstract: A method and system is disclosed for enabling quantities of bulk-type products to be determined using RFID tags that can also be used to determine the existence of product or packaging containing RFID tags. Packaging and/or containers for the bulk products are configured so that the RFID tags contained thereon provide an indication of an approximate relative quantity of the bulk material. More specifically, the position and/or shielded or unshielded state of RFID tags are utilized to identify a quantity of the bulk-type material.

Abstract: A method and system for monitoring the availability of medical aids for a patient. A first signal transmitter is mounted on the aid for transmitting first electromagnetic signals. A second signal transmitter is worn by the patient and has a warning device for outputting a warning signal which can be perceived by the patient. A receiving unit receives the first electromagnetic signals transmitted by the transmission unit. A control unit actuates the warning device to output the warning signal when the first electromagnetic signal is received and when a predetermined reception strength for the first electromagnetic signal is undershot and when a particular item of information associated with an operative state of the medical aid is transmitted with the first electromagnetic is received.

Abstract: A method and apparatus for detecting a level of a content in a vessel using an RFID tag. In one embodiment, an RFID tag located on one side of the vessel opposite a side on which the reader is, is interrogated. A reply signal, if any, received from the RFID tag is interpreted to determine the information returned from the RFID tag. The level of the content in the vessel is determined based on the information received from the RFID tag.

Abstract: A device for establishing and/or monitoring a predetermined fill level in a container is provided, to indicate the fill level in a container and exhibiting a best possible, optimum fit for an application, which device includes: a mechanical oscillatory structure placed at the height of the predetermined fill level, which structure exhibits a membrane and two mutually separated oscillation bars formed thereon, an electromechanical transducer, which in operation excites the oscillatory structure to oscillate with oscillations, such that the oscillation bars execute oscillations perpendicular to their longitudinal axis, a receiver- and evaluation-unit, which uses the oscillations to establish and/or monitor whether the predetermined fill level has been reached, or not, in which the oscillation bars exhibit a shape in which a mass moment of inertia of a liquid quantity, which the oscillation bars move with them in the immersed state in the liquid, is as large as possible and greater than 0.

Abstract: A liquid level sensor for standard bottles containing highly viscous materials such as gels so that the bottles may be inserted into an appliance to alert a user when the bottle is empty. The holder conveniently locates the bottle in the holder which includes insert molded contacts, wire harness and seal piercing mechanism. The bottle holder will universally fits into most appliances and machines. The invention enables the use of standard bottles are liquid reservoirs such that the bottle can be discarded when empty.

Abstract: The invention relates to an apparatus for monitoring a field device for determining and/or monitoring a physical and/or chemical process parameter of a process medium with a first sealing stage facing toward the process and at least one housing with a predetermined interior volume. The housing is located on the side of the first sealing stage facing away from the process, wherein energy is transferable through the first sealing stage 4 in the direction of the process medium. This energy interacts with the process medium, wherein at least one detector unit is provided in the housing, which unit monitors at least one condition parameter of the interior volume of the housing.

Abstract: A portable liquid level detector. The detector comprises a portable casing, a power supply unit disposed in the portable casing, a sensing device coupled to the power supply unit to sense a capacitance within a container and to output a enable signal when a difference in the capacitance is detected, a light emission device coupled to the sensing unit that illuminates after receiving the enable signal, and an alarm device coupled to the sensing unit that sounds after receiving the enable signal.

Abstract: An indicator for displaying either low liquid level or satisfactory liquid level conditions within a tank includes a sensor for detecting the liquid level conditions, a photodetector for detecting an ambient dark condition, a pair of indicator lights for indicating either the low liquid level or satisfactory liquid level conditions, and electrical circuitry operable to illuminate one of the indicator lights upon detection of the ambient dark condition by the photodetector and detection of either the low liquid level condition or satisfactory liquid level condition by the sensor.

Abstract: The invention relates to a measurement instrument, especially for level and pressure measurement with a controller (9), which is connected to a memory unit (8), an input unit (11), and also an output unit (12). Here, the output unit (12) is embodied as an acoustic output unit. According to the invention, operator and/or operating parameters are stored in the memory unit (8) and can be output as audible speech signals from the output unit (12) by activating the input unit (11).

Abstract: A device for monitoring the level or amount of a material within a container is provided. The device includes a detection mechanism that can be a direct detection mechanism or an indirect detection mechanism. When the detection mechanism senses an upper level of the substance in the container that is below a predetermined lower limit for the substance, the mechanism operates an alarm mechanism to emit an audible and/or visible alarm to alert an individual to the low level of the substance within the container. The alarm mechanism can be integrally formed with the detection mechanism, or can be spaced from the detection mechanism in order to provide a more accessible point for the viewing or hearing of the alarm emitted by the alarm mechanism.

Abstract: A monitoring system includes one or more monitoring devices, positioned in sewer manholes, storm drains, etc., and a remote monitoring station that communicates wirelessly therewith. The monitoring device may be an integrated unit, including sensors, a two-way telemetry unit, a power supply, a processor, and supporting hardware, all located in an enclosed, waterproof housing. The monitoring device is placed within a manhole cavity to obtain depth (e.g., water level) measurements and report the measurements back to the remote monitoring station, which analyzes the data and responds to alert messages when a dangerous water level is detected. The sample and reporting rates of the device, as well as the water level threshold values, may be remotely programmable via commands transmitted from the remote monitoring station. An additional sensor may monitor the manhole cover for security purposes.

Abstract: A signal transmitting apparatus which makes exchanging information when pouring a liquid possible. A container body 201 of a transmitter side container 20 holds an electrically conductive liquid 402. A display 306 for confirming data reception is attached to a container body 211 of a receiver side container 21. The container body 201 and the container body 211 are electrically connected at a predetermined impedance by the liquid 402. Because digital data is modulated by a carrier of approximately 10 MHz, an electromagnetic field is generated. In particular, a return line 404 due to an electromagnetic near field is generated, and communications from the transmitter side container 20 to the receiver side container 21 becomes possible.

Abstract: A level apparatus for indicating the orientation relative to vertical of a surface of an object extending along a user line of sight, including a fluid vessel containing an indicator fluid including a liquid and having a fluid surface, the fluid vessel having a vessel abutment region with a rearward abutment wall for placing against a surface of an object to be evaluated for tilt and with a forward display wall including a fluid display window extending generally perpendicular to the user line of sight, the fluid surface being visible in the fluid display window when the abutment wall is substantially upright, and includes a vessel reservoir region extending at least one of: rearwardly and forwardly from the vessel abutment region along the user line of sight, the vessel abutment region and the vessel reservoir region being in mutual fluid communication.

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: Method and device for calculating the level of the surface of a product in a storage room by a radar level gauging system, which includes a first gauging device for calculating a first value of level and functionally separated from the first gauging device a second gauging device for calculating a second value of said level, wherein: a first signal is produced being dependent of a preset first threshold value of the level in the first gauging device, a first current level value signal is output from the first gauging device, a second signal is produced in dependence of a preset second threshold value of the level in the second gauging device, a second current level value signal is output from the second gauging device and the value of the current level of said surface is presented by an indicating unit adapted to receive at least one of the first level value signal and the second level value signal for evaluation of the current level value.

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 remote monitoring system for a mobile storage tank having a product container in which a remote telemetry unit gathers liquid level and head space pressure data and global position data. The remote telemetry unit effects a wireless transmission of a standard message structure containing the pressure and level data and the global position data. In addition, in case of a storage tank having a thermal shield fluid, pressure and level data for the shield fluid itself may also be in the standard data record as well as acceleration data from an accelerometer to indicate tank damage. If upset conditions of pressure and liquid level are reached in the thermal shield and/or product container, vapor may be vented in accordance with preset programming in order to attempt to reestablish liquid level and vapor pressure above set points.

Abstract: This invention relates to self-propelled, mobile input/output bins (MIOB). Such structures of this type, generally, allow the MIOB to provide an automated input/output job distribution. For example, the MIOB can provide a method for automated input/output job distribution, comprising the steps of: detecting an input/output job at a consumable handling device; interacting between said consumable handling device and a first self-propelled, mobile input/output bin; and contacting a second self-propelled, mobile input/output bin by said first input/output bin when said first input/output bin becomes full.

Abstract: An electronic exposure dose meter and a radiation handling operation management system is capable of realizing real time exposure management. The radiation handling operation management system has monitoring unit receiving an exposure dose amount measured by an electronic exposure dose meter having a radiation detector, its counter circuit and a PHS transmission and reception antenna, from a plurality of transmission and reception base station installed in a radiation handling operation site through bidirectional communication with a central management section via an external management base station, and deriving position of user of the electronic exposure dose meter for collecting and displaying position and exposure dose amount of the user. The electronic exposure dose meter has a radiation detector, a counter circuit, a PHS antenna for bidirectional communication with a central management section.

Abstract: A monitor for monitoring presence or absence of a liquid product in a system for pumping the liquid product from a supply through tubing. A capacitive sensor is coupled to the outside of the tubing at a sensing location having an inlet and an outlet, the capacitive sensor being responsive to the presence or absence of the liquid product in the tubing. The tubing is selected from a material and having an inside diameter at the sensing location selected such that the tubing is substantially evacuated or substantially drains when the liquid product is substantially absent from the tubing preceding the sensing location but small enough so that the liquid product can be sensed by the capacitive sensor when the liquid product is substantially present in the supply.

Abstract: An apparatus operable in a wet environment for detecting the presence or absence of water in a non-conductive vessel, by measuring changes in dielectric constant and detecting the temperature of water in same vessel. A conductive element coupled to a sensing and switching means, transmits data to the controller, resulting from a change of dielectric constant at the conductive element. A temperature sensor detects and transmits temperature signals to the controller. A controller means receives data, from the dielectric constant sensor means and temperature data from the temperature sensor. Includes a coupling means which transmits data from the controller to an external device. The isolation means electrically isolates the conductive element and temperature sensor means from the water contained in a non-conductive vessel.

Abstract: This invention relates to self-propelled, mobile input/output bins (MIOBs). Such structures of this type, generally, allow several MIOBs to communicate with one another and a data center. For example, the MIOBs can communicate with a data center if one of the MIOBs experiences a breakdown so that MIOB can be sent to assist with the breakdown.

Abstract: The invention relates to a pressure sealing device and a method for decreasing the cut-off frequency in such a pressure sealing device used in a radar level gauging system for gauging a filling level of a product kept in a container, the sealing device comprises a waveguide for feeding microwaves in at least one of the following mode types: transverse electric mode, transverse magnetic mode or hybrid mode. Said waveguide is sealed by a dielectric material. A center conductor is arranged at least partially within said dielectric material.

Abstract: Resonant decay sensors that determine a parameter based on the decay of acoustic standing waves in a tube. Parameters that can be determined include temperature, pressure, the level of a material in the tube, and the height of a material above an end of the tube. Resonant decay sensors can produce both point level and continuous level sensors. A vibration mount, such as a rubber ring, beneficially isolates an acoustic transducer from the body of the tube.

Abstract: A wireless gauge alert system including a near empty sensor, a near full sensor, a transmitter, a receiver, and an alert device used to monitor the fuel level status of a liquid fuel or pressure (vessel) tank having a measuring device with an output member and gauge. Upon detection of a predetermined near empty condition, the transmitter sends an encoded wireless alarm signal to the receiver. The alert device then generates a user notification signal. The receiver and alert device, which preferably comprise an LED, are held in a housing having a plug extending therefrom to mount the housing to an electrical socket in a high traffic area. An alternate alert system includes a receiver unit coupled with a computer that allows either the user or a vendor computer to monitor the status of the sensor and respond accordingly. Another alternate alert system includes multiple zone remote assemblies for installation on separate fuel tanks to be monitored.

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 present invention provides a highly universal out-of-liquid sensor that allows an out-of-liquid condition to be accurately detected for a long time, and provides a liquid supply device using the same.

Abstract: A three dimensional surface contouring and ranging system (10) based on a digital fringe projection (18) and phase shifting technique is disclosed. In the system, three phase-shifted fringe patterns and an absolute phase mark pattern are used to determine the absolute phase map of the object (12). The phase map is then converted to the absolute x, y, and z coordinates of the object surface by a transformation algorithm. A calibration procedure is used to determine accurate values of system parameters required by the transformation algorithm. The parameters are initially indirectly measured through experiments to determine their approximate values. A calibration plate is then measured by the system at various positions. An iteration algorithm is then used to estimate the system parameters.

Abstract: The present invention relates to a fuel level system for an automobile, and more particularly, to a fuel level system for use in informing a driver of the amount of remaining fuel in a fuel tank of an automobile using gasoline, light oil, gas or the like, wherein a flowing electric current is increased in a contact of a level sender unit. The fuel level system of the present invention comprises a level sender unit installed in a fuel tank of the automobile, a fuel gauge, and a resistor installed inside or outside the level sender unit within the fuel level system to increase an electric current flowing through a contact of the level sender unit.

Abstract: The invention relates to a device for determining the filling level of a filling material in a container. The device has a signal-generating unit, which generates electromagnetic measuring signals, a transceiver unit, which emits the measuring signals via an antenna in the direction of the surface of the filling material and which receives the echo signals reflected at the surface of the filling material, the antenna comprising a waveguide which widens in the direction of emission into a cavity of a defined shape, and an evaluation unit which determines the filling level in the container from the propagation time of the measuring signals. At least one dielectric filling material is provided which at least partially fills up the waveguide, and which virtually completely fills up the widened cavity of the antenna.

Abstract: RFID tags attached to a product contain information regarding the product and communicate this information to a reader. This information can include the age of the product, the amount of product left and preparation or care instructions for the product. To record the age of a product, a timer is initiated in the RFID tag. Thereafter, the elapsed time on the timer can be read and displayed by the reader. For other products, the RFID tag can have contacts monitoring the level of remaining product. Once the contacts sense that the amount of product is low, this information can be transmitted and communicated by the reader. Preparation and care instructions are prerecorded on the tag. Instructions can also be communicated between a product and a base, such as a heater.

Abstract: This invention relates to self-propelled, mobile input/output bins (MIOB). Such structures of the type, generally, allow the MIOB to replenish the consumable handling device. For example, the MIOB can be used to replenish the paper in a printer and/or printing device.

Abstract: A liquid in pipeline and liquid level detection and warning system and some of its applications are provided. The liquid in pipeline and liquid level detection and warning system is incorporated into a liquid delivery unit. The liquid delivery unit includes a pipeline serially linking a liquid tank, a buffer tank and liquid outlet element. A drainage unit is also positioned under the outlet element for collecting redundant liquid. The warning and detection system includes a liquid in pipeline warning system and a liquid level warning system. The liquid in pipeline warning system has a first liquid in pipeline sensor installed on the pipeline between the buffer tank and the outlet element and a second liquid in pipeline sensor installed on the pipeline between the liquid tank and the buffer tank. The liquid level warning system has a first and a second liquid level sensor installed on the drainage unit such that the second liquid level sensor is positioned below the first liquid level sensor.

Abstract: A system for monitoring the conditions within the fuel storage compartments of a transport tank comprises an overfill pressure vacuum probe installed in each fuel storage compartment and which has a first sensor for detecting the presence of fuel at a predetermined level in the compartment, and a second sensor for detecting the pressure of a gaseous head above the fuel. A signal generator responsive to said first and second sensors produces a first signal representing a normal condition when the first sensor is not detecting fuel in the compartment at the predetermined level, a second signal when the second sensor detects a predetermined predetermined high pressure of the gaseous head, and a third signal when the second sensor detects a predetermined low pressure of the gaseous head.

Abstract: A device for establishing and/or monitoring a predetermined fill level in a container is provided, to indicate the fill level in a container and exhibiting a best possible, optimum fit for an application, which device includes: a mechanical oscillatory structure placed at the height of the predetermined fill level, which structure exhibits a membrane (3) and two mutually separated oscillation bars (7) formed thereon, an electromechanical transducer, which in operation excites the oscillatory structure to oscillate with oscillations, such that the oscillation bars (7) execute oscillations perpendicular to their longitudinal axis, a receiver- and evaluation-unit (13), which uses the oscillations to establish and/or monitor whether the predetermined fill level has been reached, or not, in which the oscillation bars (7) exhibit a shape in which a mass moment of inertia of a liquid quantity, which the oscillation bars (7) move with them in the immersed state in the liquid, is as large as possible and greater than