Abstract: In a fire detector that includes a sensor for producing an output voltage corresponding to smoke concentration, temperature, etc., there is provided a charge-and-discharge circuit to be reset by the turning ON of a switching circuit which is made ON at a fixed voltage. The output of the charge-and-discharge circuit and the output of a sensor are applied to the switching circuit to vary the ON period of the switching circuit corresponding to the output voltage of the sensor. Any irregularity in the sensor can be monitored by changes in the ON period.

Abstract: An electric cooker having means for warning the user when one or more of the cooking surfaces is above a safe touching temperature comprises a glass ceramic cooking surface having one or more electrical heaters arranged on the underside of the cooking surface. A temperature monitoring device is thermally coupled with at least one of the one or more heaters and comprises an auxiliary heater, for example of PTC material, a thermally responsive device in the form of a thermistor, for example of PTC or NTC material, and a thermal buffer positioned between the auxiliary heater and the thermistor. A neon lamp or a filament lamp is provided for indicating when the thermistor is at or above a predetermined temperature.

Abstract: Two substrates respectively mounting electric parts are disposed so that parts-mounting faces of the two substrates oppose each other. The opposed substrates are connected at the respective opposing side edges thereof to each other by means of respective cover plates. High voltage electric parts are mounted on one of the substrates, while heat/electromagnetic wave generating electric parts are mounted on the other of the substrates to obtain heat radiation and electromagnetic wave shielding.

Abstract: The temperature probe is biased for causing current flowing therethrough to be proportional to the probe temperature. A variable set point temperature is represented by a variable reference current which is summed with the temperature probe current. An output signal is produced therefrom to indicate the relationship between the set point temperature and the probe temperature.

Abstract: A ceramic encased thermocouple placed within a kiln electrically controls an array of signal classifiers which, in turn, control the operation of the kiln heating elements. The temperature value at which the classifier array terminates the whole kiln heating operation is preselected as one of a plurality of discrete predetermined values corresponding to pyrometric cone temperature values.

Abstract: A system for monitoring the temperature of a plurality of bearings and motors, for example in a grain elevator, includes a plurality of sensors associated with the respective bearings and motors whose temperatures are to be monitored. A first circuit energizes a display for providing a readout of the temperature at each sensor location, and a second circuit compares the temperature at each sensor with a maximum desired temperature for its associated bearing or motor, and energizes an alarm when this desired maximum is exceeded. A third circuit drives a display indentifying the sensor being monitored by the first and second circuits. A malfunction detector circuit produces an observable indication in response to an open circuit condition at any of the sensors.

Abstract: An electronic device comprises an arrangement which makes it possible to power a transmitter in self-contained fashion from a pick-up without any other power source. The device comprises at least one transistor and a transformer having a high turns ratio. The primary windings are connected in series with controlled electrodes of the transistor. The secondary windings of the transformer act on the controlling electrode of the transistor and the very low voltage is applied across the primary windings and the controlled electrodes. Voltages of a few mV which are thus applied result in the appearance of voltage pulses of a usable magnitude at the terminals of the secondary winding which may be accumulated in a capacitor to feed the transmitter intermittently. This device can be used in a self-contained detector-transmitter for use as a remote fire alarm.

Abstract: The invention provides a fire detection system which comprises an electric thermal transducer such as a thermistor placed in a turbulent gas stream. The transducer produces a signal, having an AC and a DC component, which signal is preferably amplified. The components are separated out in a discriminator, for instance an AC amplifier and the AC component is squared and integrated to give a final output which is proportional to the temperature of a heat source, such as a fire, upstream of the transducer. The invention also provides a fire detection system comprising a series of transducers connected to a single processing apparatus, the signal from the transducers being compared to locate a heat source. The invention also provides a method of detecting a fire using a system as described above.

Abstract: The Unused Fuel Indicator (UFI) comprises a reliable thermo-electric/electronic circuit employing thermocouples attached to the catalytic converter of an emission control system for an automobile engine for providing easy readout of the condition of the automobile engine and the emission control system. A preferred kind of readout is provided by the sequential glowing of light indicators such as light emitting diodes (LEDs) wherein the sequence in which the LEDs are caused to glow, and their color is indicative of the proper functioning (or malfunctioning) of the automobile engine and catalytic converter emission control system. The UFI incrementally indicates the potential heat of pollutants in an automobile engine exhaust, which pollutants are converted by oxidation to heat produced by the catalytic converter. The heat is sensed by thermocouples which are differentially connected with the output of one opposing the output of the other.

Abstract: A fire detecting system which is capable of successively controlling the forecasting of a fire, setting off alarms and activating fire-extinguishing equipment. The system includes a detector adapted to produce an electric impedance corresponding to an amount of a fire generated object present, such as smoke density, light or heat. An amplifier element has a controlling electrode connected to the detector so as to amplify the change in the electric impedance transmitted by the detector. A voltage-differential actuated element is connected at its one input terminal to the connection terminal of the amplifier element. To the reference input terminal of this voltage-differential actuated element, connected is a reference operation voltage changing means which is controlled by a time constant circuit which is adapted to determine the duration or time length of the output from the voltage-differential actuated element.

Abstract: A heat sensor, typically a cold-conductor resistor with a high temperature coefficient, is located close to a bearing of the alternator. It is connected to an evaluation network which, in turn, is connected to the charge control indicator to cause the charge control indicator to provide a trouble indication if the temperature of the bearing rises above a predetermined limit.

Abstract: A two-wire fire sensing and receiving system having a plurality of fire sensors connected in parallel in which;the difference in current level between a feeding electric current of a relatively small level for controlling the system and a sensing current of a relatively high level for causing the switching element of an alarm device to be conductive is reliably maintained to distinguish their current levels by restraining the current which tends to increase at the beginning of capacitor charging and at intermittent charging periods within the level of the feeding electric current without being affected by the fluctuation in power supply voltage.

Abstract: A temperature responsive apparatus includes a thermocouple producing a thermoelectric e.m.f. depending on the temperature difference between a temperature to be detected and a circumferential temperature and a first winding supplied with current from the thermocouple to generate a first magnetic field. A second winding is connected to a voltage source to generate a second magnetic field in the opposite direction to that generated by the first winding and a reed switch is positioned in the total magnetic field generated by the first and the second windings so as to respond to the intensity of the total magnetic field to make and break its contacts. A diode is also connected to the voltage source, and the second winding is always excited in accordance with the voltage drop across the diode to maintain said second magnetic field.

Abstract: A protective arrangement operating in conjunction with a multiplexing system adapted to convey data from a plurality of low-impedance analog sensors to a central digital receiving terminal. Each sensor is coupled by an input line through a noise-rejection filter that includes a capacitor connected across the line to a commutator serving to sequentially sample analog data derived from the sensors and to apply the samples to an analog-to-digital converter. The protective arrangement functions to detect the occurrence of an open circuit in any one of the sensors and to produce an indication of this abnormal condition, the arrangement including a like plurality of photon-couplers, one for each sensor. The light-emitting diode of each photon-coupler is energized by a power source common to all sensor circuits. The light emitted by the diode is intercepted by a photo-transistor connected through resistors of high value across the related sensor input line to define a network generating a small offset-current.

Abstract: A thermocouple-probe assembly for use in the measurement of temperature in a gas-turbine engine. The assembly has a central hub which is for mounting on the central exhaust-cone of the engine and twelve elongate thermocouple probes which extend radially from the hub such that their operative tips are located in the gas flow through the engine. Each probe has two Chromel-Alumel junctions at its operative tip, the junctions of each probe being electrically interconnected by means of four concentric electrically-conductive rings which are mounted coaxially within the hub. Two of the rings are of Chromel and two of Alumel, the wires forming the thermocouple junctions being connected to rings of the same material by means of small edge portions of the rings which are turned back and crimped around each wire. External electrical connection to the probes is made by cables connected to the rings within the hub.

Abstract: A high-temperature detecting apparatus most suitably used with a system for protecting a catalytic apparatus provided for purifying exhaust gas of an automobile is disclosed. A reed relay coil is connected between the cold junctions of a thermocouple in such a manner that the reed relay is driven directly by an electromotive force generated in the thermocouple due to heat in the exhaust gas. The thermocouple and the reed relay are integrally arranged by means of a metal cover. This arrangement reduces the connection resistance between the thermocouple and the coil, thereby making it possible to directly drive the reed relay by the output of the thermocouple.