Abstract: A salinity indicatory system useful to monitor variations in the salt content of water sources provides for the simultaneous monitoring of a plurality of test stations and the operation of automatic alarm and dumping means when salinity concentrations reach or exceed predetermined set points. The alarm and dump set points are capable of being set at different levels to provide for an indication of an approaching dump condition. The system includes temperature compensating networks having thermistors and associated resistor networks mounted inside the salinity cell to function both as temperature shaping resistors and electronic scaling resistors, thereby providing the system with multi-range capability. A summary fault alarm circuit allows all alarm conditions occurring with respect to any of a plurality of perimeters to be signaled through a single, summary fault relay.

Abstract: In the disclosed battery voltage checking apparatus a first detector detects a first battery voltage level and a second detector detects a second battery voltage level. The first detector produces a signal to instruct the operator to replace the battery when the voltage level of the battery is below the first battery voltage level. Another signal is produced to inhibit camera operation when the battery voltage is below the second battery voltage level. The apparatus includes a circuit arranged to cause the first and second detectors to simultaneously detect the battery voltage level and another circuit arranged to process the signal produced from the first detector before processing the signal from the second detector.

Abstract: A toilet reservoir fill alarm including water level sensors which can be positioned in the water reservoir tank of a flush toilet to detect the presence or absence of water at a desired level. A switch responds to the water level sensors and produces a control signal during the absence of a desired level. The control signal operates a timing circuit in order to produce an output signal at the termination of a predetermined time interval. Responsive to the output signal is an alarm circuit. In this manner, an alarm will sound should the toilet tank reservoir not refill during the predetermined time interval following the flushing of the toilet.

Abstract: A sewer line backup detection device and alarm are provided which can be installed in place of the cleanout access cap in a conventional sewer line. The device comprises a housing having male connecting threads adapted to fit standard female receptacles which have been used in the past to provide cleanout access to sewer lines, the housing containing alarm means or alarm transmitting means actuated by a pneumatic switch. The pneumatic switch is actuated by a flexible diaphragm which is fitted snugly onto the lower end of the housing which extends into the sewer line. In the event of a blockage of the sewer line, the blocked material exerts pressure on the flexible diaphragm which closes the pneumatic switch thereby setting off an alarm, either locally or at a remote location such as the dwelling from which the sewer line exhausts. The alarm system is utilized especially advantageously in combination with a detention tank located in the basement or lower level of a high rise building.

Abstract: Instead of monitoring a thermal deburring operation by reference to whether a certain high temperature is reached and thereby indicting whether a successful ignition in the deburring chamber has taken place at every step of operation of the chamber, a circuit responsive to the rate of change of temperature is used to recognize a successful operation, thus permitting faster operation of the apparatus. Such a circuit is also useful for rapid detection of a short circuit circuit in electrochemical apparatus utilizing heavy electrical currents and variable amounts. In the latter case a digital circuit for measuring the amount of change at equal intervals of time is particularly useful.

Abstract: A contactless motion detector responsive to the approach of a ferromagnetic element, including an oscillator with a sensing coil, has an output lead connected to one input of a first Exclusive-OR gate having another input connected to a square-wave generator whose pulses appear in the output of that gate with or without phase inversion depending on the output voltage of the motion detector. These pulses are fed, via an amplifier, to one input of a second Exclusive-OR gate whose other input receives the output pulses of the square-wave generator directly but with a delay compensating a lag introduced by the first gate and the amplifier. In the absence of a malfunction, the inputs of the second gate are energized either cophasally or antiphasally to produce either a low or a high output voltage of substantially constant magnitude fed to a load; in the event of a malfunction interrupting the pulse transmission to either input of this second gate, its output becomes a pulsating voltage.

Abstract: Method and apparatus for detecting the presence of liquid in a container includes an elongate rod (or other vibratory element) which extends into the container to contact liquid when a certain amount of liquid is present, a piezo-electric element coupled to the rod on the exterior of the container to cause the rod to vibrate in response to electrical signals and to produce electrical signals indicative of the amplitude of vibration of the rod, and circuitry for producing a utilization signal when the electrical signals produced by the piezo-electric element indicate that the amplitude and duration of vibrations of the rod are below some threshold level. Such vibrations fall below the threshold level when the rod contacts liquid in the tank and so production of the utilization signal is an indication that liquid in the container has reached a certain level.

Abstract: A battery-powered photoelectric smoke detector periodically samples the air in a smoke chamber. A manually-operated test button is provided for simulating smoke to test the device. The sampling frequency is determined by a first resistance. A frequency changing circuit includes a test switch, the movable contact of which is coupled to the test button and is responsive to operation thereof for connecting it parallel with the first resistance the series combination of a diode and a second resistance for increasing the sampling frequency. Means are provided for back-biasing the diode to disable the frequency changing circuit when the detector detects smoke.

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

Abstract: A device to be used in conjunction with oxygen cylinders or other gas cylinders which will sound a warning and/or flash a light when the gas supply is running low and the cylinder is in need of replacement. A pin is inserted through a lens which normally is placed over a gas gauge dial wherein the gauge dial has a standard indicator arm which moves when the pressure decreases. When the indicator arm moves, normally in a counterclockwise direction, it will make contact with the pin when the level in the tank has been reduced to a point where it should be replaced. This will then complete an electrical circuit which would cause an alarm to sound and/or a light to flash. The circuit comprises essentially two lead wires each connected to a battery with one of the leads connected to a metal part of the regulator and another lead connected to the pin associated with the gauge.

Abstract: A device for signalling a specific charge condition of an accumulator battery (B) comprises a comparator circuit (C) for comparing the battery voltage (V.sub.B) with a reference voltage. A switching circuit (G.sub.2, G.sub.13) is controlled by the comparator circuit and an indicator (L.sub.1, L.sub.2, L.sub.s) is in turn controlled by the switching circuit. A memory circuit (FF) ensures that the indicator remains energized for a specific time interval after the apparatus has been switched off.

Abstract: A low charge detector, for a measuring instrument incorporating a meter for indicating measurement readings, includes a "low battery detector" circuit which causes a first output to be released from a 1 Hz oscillator, when a battery pack supplying power to the instrument discharges to a predetermined level. The first output is then applied to a pointer on the meter, thus causing the pointer to execute oscillations of a relatively small amplitude.When the battery pack is substantially dead, a "dead battery detector" circuit causes a second output to be released from the oscillator and to combine with the first output. The combined output is then applied to the pointer, thus causing the pointer to execute oscillations of a substantially greater amplitude, thereby indicating that recharging of the battery pack is required.

Abstract: A smoke detector is provided with a masking shield which obscures the smoke detector housing from normal view. Particularly in the case of installation of smoke detectors in children's bedrooms, the invention prevents the detector from appearing as a representation of the threat of fire.

Abstract: A light extinction type smoke detector which uses simple pulsed light or modulation pulsed light to reduce energy consumption, and precisely discriminates smoke generated by fire from extraneous interruption of the light beam from the light source to the photoelectric element to prevent a false alarm.

Abstract: A portable alarm is provided with a smoke detecting mechanism and circuit connected to an audible signal activated on the presence of smoke and all contained in a compact housing. To this conventional combination the invention interposes a connector means in the circuit between the detector and alarm which connector means includes a highly visible elongated external hanging electrical lead that is plugged into an opening in the housing to complete the circuit through the electrical lead thus, at all times, conspicuously indicating the armed/unarmed condition of the alarm.

Abstract: In a smoke detector of the type in which smoke is detected in a detection chamber based upon a variation of an ionization current flowing therein or a variation of light beam passing therethrough, there is provided a reference signal generating section which produces a reference signal having a predetermined characteristic corresponding to typical smoke flowing into the detection chamber when a fire occurs, and a signal comparison section which compares a detection signal detected in the detection chamber with the reference signal, wherein a smoke sensing signal is produced when the detection signal is determined as a signal due to a fire but is not produced when the detection signal is determined as the signal due to the entry of an insect into the detection chamber or due to cigarette's smoke flowing thereinto.

Abstract: A method and apparatus for producing a visual signal of the state of charge of a battery selectively connected and disconnected from an external load. A test load is connected to the battery for a predetermined period of time to draw a current pulse from the battery when the battery is disconnected from the external load. Simultaneously, the voltage of the battery is measured. The measured voltage is converted to a digital signal, and the digital signal is transmitted to a storage means. The stored signal is then transmitted to a visual display device.

Abstract: An electric liquid level detector of the condenser type comprises an electrode assembly including a pair of electrodes to be submerged into the oil within a liquid container, an electric circuit assembly provided with an electric detecting circuit for generating an output signal indicative of the level of remaining oil in dependence upon an electro-static capacity between the electrodes, and a flexible tubular guide member of conductive material fixed at its one end to the electrode assembly and at its other end to the electric circuit assembly. The guide member is provided therein with an elongated partition plate of conductive material grounded together with the guide member, and the electrodes are connected to the detecting circuit by means of a pair of insulated electric wires extending through a pair of elongated spaces subdivided by the partition plate in the guide member.

Abstract: A security fence system employs a plurality of very thin, high tensile strength, highly stressed wires arranged relatively close together and between each of which is connected an electrical resistance. A voltage source causes a current to flow through the series-connected wires and resistors. An annealed segment can be formed in each high tensile strength wire and located between the points where each wire is attached to the fence posts, to make stretching of the wires without breaking them impossible. A sensing circuit is connected to the fence and includes voltage comparators and potentiometers for providing adjustable triggering levels. The comparators detect when the current flowing in the fence is altered and trigger an alarm if any of the wires are broken, or if any of the wires contact one another. The alarm can be turned off only by normalizing the fence and actuating a reset switch.

Abstract: A smoke detector receiving at two input terminals DC power from a remote source not only gives an alarm indication in response to a significant density of smoke, but senses the polarity of DC power at the terminals and generates a secondary signal, distinguishable from the alarm signal, when the polarity of power source is reversed.