Abstract: A method, system and computer program product for adaptively tracking the position of an entry portal, such as an automatic garage door. In accordance with the present invention a transmitter assembly senses and transmits the sensed position of the door position in a periodic manner at a predetermined transmit interval. A receiver assembly including a receiver module receives the transmitted door position signals and synchronizes the activation of the receiver module with the transmit interval such that the receiver receives the door position signals transmitted at the predetermined transmit interval. A receiver output indicator is then updated in accordance with the entry portal position determined by the received door position signal.

Abstract: The application discloses various methods and systems that utilize infrared communication to enhance and manage the security and convenience of occupants and the operation and efficiency of the staff of a multi-unit building.

Abstract: A system for monitoring an environment comprises a plurality of sensors, each sensor generating respective events in response to activity in the environment. A processor is in operative association with the sensors, and at least one stored set of linked events are accessible to the processor. The processor is responsive to an event being generated by a sensor to determine whether the event is in a sequence of events corresponding to a stored set of linked events and to generate an alarm accordingly.

Abstract: System and method for monitoring a working status of a swimming pool cover assembly. The system comprises a pool cover assembly operably connected to an alarm apparatus; both may be operably connected to a plurality of sensors capable of detecting a working status of the pool cover assembly and sending a signal to the alarm apparatus. The alarm apparatus continually produces at least one humanly perceptible indication corresponding to a working status of the pool cover assembly. The alarm apparatus includes at least one alarm-producing device, such as an audio or visual device, or combination of the two, a receiver operably connected to the plurality of sensors for receiving the signals, a processor operably coupled with the receiver for processing and recognizing the received signals, and software operably coupled with the processor enabling the alarm-producing device to produce the humanly perceptible indication corresponding to the recognized signal.

Abstract: An electronic alarm and a vending machine equipped with the alarm monitors a plurality of zones by suitable circuitry to detect vandalism and theft. Each zone has a mechanically-triggered sensor that provides an electrical output. The zones comprise a pair of door sensors and a separate, shock sensor. A solid-state logic circuit includes a red and green indicator light, and a loud warning buzzer ultimately triggered by the sensors. A circuit time delay and logic scheme analyzes sensor status, and separate false-alarm prevention circuits insure proper triggering after a predetermined delay. Alarm status is indicated by highly visible green and red status lights mounted on the door. A buzzer sounds in response to sensor activation and circuit logic. A back-up battery that is coupled to the logic circuitry for fail-safe operation includes an automatic recharge system, and dual red and green LED's monitor battery condition.

Abstract: An improved electronic mailbox increases the difficulty of stealing mail from the mailbox. The mailbox includes an electronically programmed access door, a mail slot shaped to prevent access to the mail box, and an auxiliary backup power system.

Abstract: A cash register alarm system for sounding an alarm to the police without delay. The cash register alarm system includes a cash drawer having a bottom wall and a back wall, and also includes a tray having a bottom wall and a back wall and plurality of partitions spaced apart and forming compartments therebetween, and further includes a plurality of sensors disposed in the compartments in the bottom wall of the tray, and also includes a plurality of electrical current contact members disposed upon the back walls of the cash drawer and the tray. More than one compartment without paper money will expose the sensors to light which will acutate the alarm system to the police.

Abstract: A system for monitoring the contents of a closed container is provided. The system includes a sensing system for monitoring the contents of the container; a signal receiving element for receiving sensor data from the sensing system; a control element for analyzing received sensor data; a first transceiver element for receiving signals containing sensor data from within the container and for transmitting those signals outside of the container; and a satellite transceiver element for receiving signals from the first transceiver element and for forwarding the received signals via satellite uplink to a remote location.

Abstract: A security system is provided for a cargo container having a door. An electronic control unit is provided for monitoring the locked status of the door. The electronic control unit is operably communicable with a remote computer terminal. A first software control program is located within the electronic control unit to monitor the locked status of the door. A second software control program is located within the remote computer terminal and is capable of retrieving activity and functions from the first software control program. A protocol is provided to facilitate communication between the electronic control unit and the remote computer terminal.

Abstract: A system and method for monitoring the activities of a resident living independently to distinguish normal activity from unusual activity. A variety of sensors distributed around the home collect data on activity in the home. The data is communicated to a remote monitoring center and collated in a database according to applicable time slots. The time slots for a twenty-four hour cycle are at least three and can be as many as forty-eight or more. Historical activity time lines are created and a buffer time is added to and offset from the maximum historical activity time line. If a new data point comes in that exceeds both the maximum historical activity time line and the buffer time, an alert is issued indicating the activity is unusual.

Abstract: A compact size wireless sensor for sensing a change of state that includes a sensor switch, a microprocessor, a wireless transmitter, a timer (e.g., a low power clock circuit), an antenna, and a coin cell battery power source. The coin cell battery, which is positioned in a stacking arrangement with the microprocessor, switch, and transmitter, allows the sensor to be of a significantly reduced size. Moreover, to provide long life despite a small battery, the microprocessor is run in a standby mode in which the microprocessor draws little power unless it actually samples the state of the sensor switch during select intervals. Various electronic components individually, or in combination, assist in the sampling (monitoring mode) in such a way as to reduce current consumption from the power source. The compact size makes the sensor ideally applicable for wireless intrusion systems embedded within hollow frames of windows and doors.

Abstract: A modular intrusion detection system that includes a base unit having a primary intrusion detection device and a housing. The primary housing includes a base housing section and an outer cover. The base housing section includes a first mounting interface. A plurality of different secondary housing sections having a second mounting interface which can be attached to the first mounting interface of the base housing section are provided. The secondary housing sections may have a functional device, such as a CCD camera or a microphone, associated therewith. The camera or microphone may be activated to an alarm signal generated by the intrusion detection device. A plurality of different base units, each having an intrusion detection device, may also be provided wherein each of the base units is attachable to each of the secondary housings, and secondary devices associated therewith, to provide flexibility in assembling individual devices.

Abstract: A portable security alarm device for use with personal baggage wherein the personal baggage includes an opening and closing mechanism, the security alarm device including a trigger mechanism for determining when the personal baggage is in at least a partially opened position, an alarm mechanism for emitting an audible alarm when activated, an operator input device operable for selectively activating various states of operation of the device including an activated state, an off state, and a programming stat wherein a user can reprogram the access code inputted into the operator input device to activate certain states of operation. The present device likewise includes a Panic button for immediately activating the alarm mechanism and a removably attachable/detachable mechanism which enables the present device to be portable for attaching and detaching to a plurality of different personal baggage.

Abstract: A method for detecting entry into a secure area uses a passive entry detector. The secure area has an access door, having a closed position. The passive entry detector comprises a source of energy internal or external to the passive entry detector, an activator for detecting a change in the access door from its closed position, and for releasing the energy in response to the change of the access door from the closed position. The energy is transferred to one or more pseudo random units. Each of the pseudo random units has a plurality of mechanical states. The pseudo random units are responsive to the activator. The activator induces a change of the mechanical states in the pseudo random units upon transfer of energy. The pseudo random units report the mechanical states upon interrogation. Using above passive entry detector, a first interrogation using the interface is performed to create a first record to identify one or more mechanical states with the access door in the closed position.

Abstract: A door/window/mailbox alarm system comprising a switch, a transmitter unit, a receiver unit and a warning means. A user is reminded to check and close an opened door/window/mailbox by the warning means on the receiver unit which is located away from the door/window/mailbox and in a close proximity to the user's active area such that the user could see or hear a warning signal from the warning means easily. The transmitter unit comprises a timer device that enables the transmitter unit to send out a preset signal every “x” amount of seconds to the receiver saying the door/window/mailbox is still open and serves as a reminder.

Abstract: A door condition sensor for a safe having a door. The sensor has a housing mounted on an inside surface of the door, frame engageable means for abutting the door frame, a driver rotatably mounted in the housing, analog signal generator mounted in the housing having a rotatable part driven by the driver, and spring for extending the frame engageable means that is slideably mounted and confined to linear displacement in the housing. The driver transforms displacement of the frame engageable means into rotational orientation of the driver. The generator produces analog signals corresponding to the rotational orientation of the rotatable part. A means converts analog signals from the generator to corresponding digital signals that are proportional to displacement of the frame engageable means. Memory means compares the displacement with a set point range thereby continually monitoring the condition of the door.

Abstract: A membrane for a cover for closing a container having the general form of a cylinder and being compressible in the direction of the axis of the cylinder. The membrane comprises two mutually parallel, generally flat parts arranged to move axially in relation to each other guided in the movement by guiding elements; resilient element arranged to generate a counterforce between the flat parts during compression of the membrane in the direction of the axis; at least a first and a second electrical contact device operated by the axial movement between the circular parts, the combined electrical settings of which contact devices will carry information about the compressions and decompressions of the membrane and elements for presenting the settings to the outside of the membrane. A cover comprising such a membrane and use thereof are also described.

Abstract: Techniques are provided for object management. In certain implementations, object management includes determining whether a signal representing the presence of at least one object to be monitored has been received and determining whether a signal representing the state of at least one object to be monitored has been received. If a signal representing the presence of at least one object to be monitored has been received, a determination is made as to whether a predetermined quantity of objects is present. If a signal representing the state of at least one object to be monitored has been received, a determination is made as to whether at least one object has a predetermined state.

Abstract: A detection apparatus for detecting refrigerator door openings is coupled to at least one switch configured to be activated by a door opening. When the door is opened, the switch is activated and inputs a signal to the detection apparatus. The detection apparatus rectifies the signal; and phase-shifts the rectified signal so that it leads or lags the line voltage. The shifted output signal is fed to a processor that detects the opening of the door based upon the shifted signal. Signals output by a plurality of switches that generate a signal when activated mixed using an opto-coupler. Relative impedance of the lead and lag circuits may be adjusted to differentiate a phase shift of one shifted signal relative to another signal. The processor converts a value in degrees of phase shifting of the mixed signal to a time value, and based upon the time value, the processor determines which of the doors is open.

Abstract: An apparatus and method for determining the location of a medication container, such as an intravenous bag.

Abstract: The apparatus for providing notices to a user interface concerning status of at least one item in a container involves a loading opening and a collection opening, a first sensor connected to the loading opening for generating a first signal when an item is inserted in the container, a second sensor connected to the collection opening for generating a second signal when the item is removed from the container, an intelligent device connected to the first and second sensors for receiving the signals and generating intelligent device signals, a communication system in contact with the intelligent device for receiving the intelligent device signals, a software interface in contact with the communication system that processes the intelligent device signals, and a user interface in contact with the software interface that receives the intelligent device signals processed from the software interface.

Abstract: Door sensor(s) may be attached to a door body or bodies of automatic swing doors. The door sensor(s) may be equipped with door position detectors including geomagnetic sensor(s), the sensor(s) being itself or themselves capable of detecting position(s) occupied by the door body or bodies during opening and/or closing thereof. During opening and/or closing of the door body or bodies, determination may be made as to whether detected object(s) are object(s) intended for detection; and in the event that object(s) are object(s) intended for detection, opening and/or closing of the door body or bodies may be stopped, slowed, and/or reversed in correspondence to detected position(s) occupied by the door body or bodies during opening and/or closing thereof.

Abstract: A protective cover assembly is provided. The protective cover assembly includes a flexible cover and an alarm assembly. The flexible cover includes an outer layer of flexible material, an inner layer of flexible material, and at least one layer of tear resistant material positioned between the outer and inner layers. The alarm assembly includes a pair of conductor plates positioned between the outer layer of flexible material and the inner layer of flexible material, a power source, and an alarm system electrically connected to the power source and at least one of the first and second conductor plates such that upon an electrical conducting implement piercing the first conductor plate and contacting the second conductor plate an electrical connection is established between the first conductor plate and the second conductor plate thereby causing the alarm system to emit an alerting signal.

Abstract: A data acquisition system includes a product for shipment to an end user, a sensor system removably connected to the product for recording environmental conditions to which the product is exposed, and a computing device, which upon being connected to the product, is operable to retrieve the recorded environmental conditions. The product may be operable to control the operation of the sensor system, or the sensor system may be operable to record environmental conditions independent of the operation of the product.

Abstract: A system to capture data regarding conditions in a sealed metal shipping container having: a sensor unit mountable inside the container and adapted to sense a condition inside of the container; an impulse radio transmitter receiving data from the sensor regarding the condition and transmitting an impulse radio wireless signal inside of the container; an impulse radio receiver external to the container and proximate the container, wherein the receiver is adapted to receive the impulse radio wireless signal propagating through the sealed metal shipping container, and a data device in communication with the receiver to capture the data from the sensor unit regarding the condition inside of the container.

Abstract: A watertight door seal compression indication apparatus is provided that includes a watertight door in a frame that has a casket disposed in a channel around the periphery of the door. A knife-edge on the doorframe is positioned to compress the gasket upon latching the door shut. Numerous switches are placed between the channel and the gasket and the switches are closed when the knife-edge edge fully compresses the gasket. A display that is responsive to the switches indicates whether the gasket was sufficiently compressed or not by either a green LED or a red LED respectively.

Abstract: A vehicle security system includes a protective cover incorporating a battery operated alarm unit contained within a pocket that is attached to the inner surface of the cover. A cable contained within the cover removably connects a switch actuating plunger of the alarm unit to the vehicle for operating a switch to activate the alarm unit, producing an audible alarm in the event an intruder attempts to remove the cover from the vehicle.

Abstract: The invention provides a security system comprising a security apparatus and a monitoring unit which provide a user with real time security information. The security apparatus comprises a housing, a mounting bracket attached to the outside of the housing, the mounting bracket configured for attachment to a secured item and comprising a switch, the switch configured to produce a first indication when the mounting bracket is attached to the secured item and a second indication when the mounting bracket is removed from the secured item, a power source positioned inside the housing, a transceiver positioned inside the housing and connected to the power source and an electronic circuit positioned inside the housing and connected to the power source, the transceiver and the switch of the mounting bracket. The transceiver is configured for communication with the monitoring unit.

Abstract: A computer-server rack enclosure fault light diagnostic system and a method for providing an overall rack level fault indicator of a fault incurred by a unit of electronic equipment housed in the rack. The rack may be an EIA standard rack holding constituent components complying with EIA standards.

Abstract: A saw cover safety sensing device comprises a protecting cover; a sensing controller at one side of the protecting cover; a control circuit within the sensing controller; the control circuit serving for receiving electric static signals from a human body and emitting control signals; the sensing controller further comprising a power switch, at least one batteries, a plurality of LED lights and a transparent cover; at least one signal sensing wire connected to the sensing controller; each signal sensing wire having a metal foil sheet; one surface of the metal foil sheet being coated with glue so that the metal foil sheets and the signal sensing wires are adhered to the protecting cover; the signal sensing wire and metal foil sheets serving for detecting electric static signals emitted from a human body; and a buzzer connected to the sensing controller; the buzzer buzzes in response to electric static signals.

Abstract: A security alarm with a wired remote triggering device consists of a triggering switch with two spring blades and a flexible sleeve tube holding both spring blades together. The security alarm with a strap is hung on the doorknob inside a door or placed inside a drawer, and the triggering device is set up from outside of the door or the drawer by pulling off the flexible sleeve tube. The two spring blades will thus be clipped in a gap between the door and its frame to keep the alarm circuitry open. When any unauthorized person opens the door or the drawer, the triggering device will fall off from the gap; thus the two spring blades will automatically open to keep the alarm circuitry in close status so as to activate the alarm, so the theft deterrent purpose is consequently achieve.

Abstract: An automated, flexible and programmable system to update delivery and inventory status for an aggregate of remote mailboxes, bins, shelves, sorter bins, and/or a plurality of bins to distant customers and vendors through email, pager, personal digital assistant (PDA), cellular phone mail, voice mail at call centers and/or web site mailboxes. It can function as a delivery notice to mailbox recipients or as inventory stock management to store owners and vendors at remote locations. Various sensors mounted on flexible circuit boards located on the mailboxes, bins, or shelves together with distributed microcontrollers report status through a common bus to a master controller and then to a computer system. The computer in turn dispatches reports and information to various owners and vendors via a remote network operation center accessed through a dedicated line, a wireless service or an Internet Service Provider.

Abstract: An automatic door system capable of distinguishing between a door closing action for when an object leaves a prescribed area, which results from a “signal discontinuation due to the exit of an object”, and a door closing action for when an object remains stationary within the area for a certain period of time, which results from a “forced signal discontinuation in the presence of a stationary object”. Regarding the latter case, the automatic door system protects a person who stops in the area by setting the door to close at a low speed and/or issuing a vocal warning. The door closing action of the automatic door system can thereby reduce the risk of hitting the person with the door.

Abstract: A mailbox and counter combination device for determining a number of times a mailbox has been opened includes a mailbox having an opening extending therein. A door is hingedly coupled to the mailbox such that the door may be selectively positioned in an open position or a closed position with respect to the opening. A sensor is adapted for detecting when the door is moved from the closed position to the open position. A processor is operationally coupled to the sensor and is adapted for recording a number of times the door is moved to the open position.

Abstract: One or more magnets are placed in a container (preferably on objects inside the container) and the magnetic field strength and vector direction are measured with a magnetometer from at least one location near the container to provide the container with a magnetic vector field tag and seal. The location(s) of the magnetometer relative to the container are also noted. If the position of any magnet inside the container changes, then the measured vector fields at the these locations also change, indicating that the tag has been removed, the seal has broken, and therefore that the container and objects inside may have been tampered with. A hollow wheel with magnets inside may also provide a similar magnetic vector field tag and seal. As the wheel turns, the magnets tumble randomly inside, removing the tag and breaking the seal.

Abstract: A tamper-resistant remotely monitorable electronic seal including a shaft portion, a socket arranged to engage the shaft portion in a monitorable manner, whereby disengagement of the socket and the shaft portion results in a monitorable event, and a wireless communicator associated with at least one of the shaft portion and the socket and being operative to provide a remotely monitorable indication of the monitorable event.

Abstract: A compact, self-contained, self-powered, autonomous, consumer alarm device within the appliance unit utilizing three visual indicator means and one audible indicator means for providing an indication of normal operation and 4 alarm conditions. The alarm device provides visual and/or audible indications in the event 1) the appliance air temperature is normal; thereby, below the maximum temperature as recommended by the USDA for storage of food, 2) the appliance door is open/ajar for more than five minutes, 3) the appliance air temperature is greater than 40 degrees F., the maximum temperature recommended by the USDA for storage of food, 4) the appliance air temperature has been greater than 40 degrees F. for a period of more than 2 hours, thereby surpassing the USDA guidelines for food which should be consumed by humans, 5) the appliance air temperature has been elevated for “X” amount of time, wherein “X” equals the quantity of hours and 6) battery voltage is low.

Abstract: A container for wafer like objects includes a container body and a door closing the container body and which is provided with a device for locking and unlocking the door, including locking elements and holding elements in which the locking elements that lock the door engage. At least one locking element includes a first signal element which is operatively connected to a second signal element arranged at a position important for the engagement of the locking element in the holding element.

Abstract: A device (12) facilitates sealing and tracking of a container (18). The device includes a bolt (166) which extends through openings in a latch mechanism (19) on the container. The bolt also passes through spaced coils (251, 252) of the seal device. The seal device uses one coil to generate a magnetic field, while monitoring the corresponding magnetic field induced in the other coil. Tampering with the bolt affects the magnetic field, which in turn permits the seal device to detect the tampering. The seal device periodically transmits wireless signals (71), which can be remotely received for purposes of tracking the container and monitoring the integrity of the seal.

Abstract: A pre-injury contact warning device for a front door of an automatic dishwasher or oven, the front door being openable to a generally horizontal very low position above the floor. In one embodiment, the device includes a housing attachable to a surface of the front door. A warning signal emitter sensorially perceptible by a person receives electric power from a miniature storage battery mounted within the housing. An angle-sensitive switch mounted in the housing is operably interconnected between the warning signal emitter and a proximity sensor. The switch is open and the proximity sensor and the warning signal emitter off when the front door is closed, while the switch is closed and the warning signal emitter is armed and on standby when the front door is open. When a person gets within a predetermined distance from the open door, the proximity sensor activates the warning signal emitter.

Abstract: An wireless security sensor system includes a window frame defining a window opening, a window sash movable relative to the window frame between open and closed positions; and a sensor unit embedded in the window frame. The sensor unit includes a housing having an inner end within the window frame, an outer end at a surface of the window frame and a flexible ¼ wave wire antenna extending e.g. longitudinally of the window frame from the housing. The housing contains a sensor switch, a microprocessor, and RF transmitter and a battery for emitting signals to a master station or controller and the wireless security sensor system includes a magnet mounted in the window sash for actuating the sensor switch. The window frame is made from a plastics material extrusion having a hollow interior and the housing has a peripheral flange at the outer end thereof which is seated on the surface of the window frame.

Abstract: In a first aspect, the present invention is a method, apparatus, and system for detecting a change in position of a door or a window in an alarm system with a singular housing having a magnetometer for monitoring the magnetic field of the earth, and a microprocessor for detecting a change in the position of the singular housing with respect to the magnetic field of the earth. The microprocessor generates an alarm signal upon detecting the change, and causes the alarm signal to be transmitted, by wireless transmission, to a remote receiving station. The device may also be used to determine if an object that it is affixed to has been moved, such as for a theft alarm for an object such as a painting. In a second aspect of the invention, a gravitational sensor is used to monitor the gravitational field of the earth and determine if an associated object or person has been moved with respect to the gravitational field, thus providing motion detection and signaling an alarm.

Abstract: A sensor device for monitoring conditions within an interior of an enclosed container which is operative to detect changes in conditions within the container caused by tampering or unauthorized access to the container. The sensor device includes a sensor dome, having a sensor, positioned within the container. An external status indicator is positioned on an exterior of the container and in communication with the sensor. The status indicator signals the current security status within the container based the signal output of the sensor. The indicator has a first condition signaling a secured status and a second condition signaling a breached status. The signals include a visual signal for an inspector on the exterior of the container indicating an unbreached or a breached container.

Abstract: The objective is the provision of intrusion detection sensor panels, which when used to enclose a closed space as a closed space apparatus, protect against the unlawful intrusion into that closed space, as well as the removal or secretion of articles into that closed space. To achieve that objective, the present invention provides a closed space apparatus comprised of intrusion detection sensor panels that detect intrusions over their entire surface. The intrusion detection sensor panels are not merely ones which incorporate a plurality of wire or point sensors over their surface, but they are characterized by being panels in which the overall panel functions to detect intrusions across its entire surface without gaps or lapses.

Abstract: A pre-injury contact warning device for a front door of an automatic dishwasher or oven, the front door being openable to a generally horizontal very low position above the floor. In one embodiment, the device includes a housing attachable to a surface of the front door. A warning signal emitter sensorially perceptible by a person receives electric power from a miniature storage battery mounted within the housing. An angle-sensitive switch mounted in the housing is operably interconnected between the warning signal emitter and the storage battery. The switch is open and the warning signal emitter off when the front door is closed, while the switch is closed and the warning emitter on when the front door is open. The warning signal emitter, when on, is sufficiently sensorially perceivable to warn or alert the person nearby the dishwasher that the front door is open and to be avoided. Other embodiments are provided which are operatively dependent upon other forms of sensory perception, e.g.

Abstract: A request for an access code for a locking mechanism is received; and a non-permanent use access code for the locking mechanism is subsequently issued. The non-permanent use access code may be issued from a list of currently available access codes for the locking mechanism in response to a request therefor, for example by a merchant or delivery service. Such a code may be issued by a server, which server is further responsible for updating the list of available access codes in response to an indication that a code has been used or has otherwise expired. Such a code may also be issued by a locking mechanism controller The list of currently available access codes is preferably a subset of all access codes for the locking mechanism, which codes may be generated using a cryptographically strong random number generator.

Abstract: A thermostated cabinet for storing articles fitted with radio-frequency identifier including a cabinet having an opening for introducing and removing articles, an article monitor comprising at least one radio-frequency receiver connected to at least one antenna for detecting movements of the articles, and means for providing data to the radio frequency identifier.

Abstract: A device and system for determining the status of the contents of a container by measuring the period of time which has elapsed since the opening of the container. The present invention provides a flexible mechanism for enabling the user to determine the usability or efficacy of the contents of the container, since such contents typically experience a higher rate of degradation once the container has been opened. Furthermore, the manufacturer is able to provide information related to the expiration date of an unopened container at the time of manufacture, but cannot determine the time at which the container is opened, and hence the expiration date after opening.

Abstract: Device for controlling a locking system, of the type including a bolt (18) intended to restrict access to a confined space and comprising an electric power supply, a clock formed of a time base and a counter, to define a time reference, an electronic circuit including a microprocessor and a memory (32); and a key board for entering commands and data, particularly with the purpose of controlling the opening of the bolt. In order to avoid any manipulation of data relating to the intervention dates, the counter includes an incrementation input exclusively connected to the time base. In this way, the information recorded in the counter is only incremented by the time base and cannot be modified by a person.

Abstract: The invention is relative to a leaktight chamber (3) in which a liquid having electrical characteristics, preferably a conductive liquid, is introduced into a leaktight volume (33) between the cover (5) and the tank (4), and in that a value of electric quantities is measured which varies with the reduction of the liquid contained in the volume (33). In such a way the leaktightness is continually checked.