Abstract: A fire monitoring system detects a plurality of types of detection information using a plurality of fire phenomenon detectors for detecting physical quantities caused by fire phenomena or using a plurality of detectors each including at least one fire phenomenon detector and at least one environment detector provided in association with the fire phenomenon detector. The plurality of types of detection information undergo consolidated signal processing for obtaining one or more types of fire information for realizing fire monitoring.

Abstract: A programmable computer-controlled fast response infrared heating system capable of precise individual zone control and especially useful for thermoforming of plastic sheets comprises an array of fast response quartz heaters on a platen, a terminal box having a CPU and mounted on and moving with the platen and which needs only one power line to it and which distributes the power to the heaters sequentially on a milli-second time basis with an essentially constant power output to each heater. The power is three phase and switching occurs only when the voltage over a relay is zero to minimize RFI/EMI emissions. The CPU is interfaced with a general purpose computer at the operator's console and a touch activated display showing the percent of available power being supplied to each heater. The operator by touch command can change the percentage of applied power for any one heater or the total power supplied to the whole of the array.

Abstract: A temperature monitoring system comprises a sensor for measuring the surrounding temperature, a timer for generating clock data, a controller for reading temperatures at predetermined intervals and storing selected temperature data and corresponding time data in memory, input switches for entering commands and data, a data display, and first and second alarm indicators. The controller operates in predetermined steps to activate the first alarm to indicate a current alarm condition and to activate the second alarm to indicate a past alarm condition. The controller selectively switches the display between normal and alarm modes to show differing time and temperature data depending on the temperature conditions monitored. The user may review alarm histories, including total alarm time and, for each past alarm period, maximum temperature, starting time and alarm duration, which have been calculated and stored.

Abstract: First sensors measure physical quantities correlated with the heat release value of a fire source, and second sensors measure physical quantities correlated with the amount of the product of burning. At least a pair of one first sensor and one second sensor are arranged in a zone to be monitored. A first threshold of high sensitivity and a second threshold of low sensitivity are set at the first sensors. A third threshold is set at the second sensors. A pre-alarm is given only when the level of signals from the second sensors exceeds the third threshold. A fire alarm is given when the level of the signals from the second sensors exceeds the third threshold and when the level of signals from the first sensors exceeds the first threshold. The outputs from a plurality of such sensors detecting different objects, such as heat and smoke, are processed in the manner in which these outputs are combined together to reliably detect fires and to give a fire alarm.

Abstract: A smoke supervisory system comprising a visible image processor for calculating a differential image between a reference image and an input image and calculating parameters in the differential image; an address overlap detector for detecting whether the differential images overlap each other; an image element number change detector for detecting a change in the image element number of the differential image; and an address ratio change detector for calculating an address ratio of the differential image; or an equipment supervisory system comprising an image fetch device for fetching a reference image and an input image from an infrared image pick up device; a mask control device for masking the reference image and the input image; a differential operation device for calculating a differential image of an unmasked dividing image; a temperature distribution difference detector for detecting a maximum temperature and a mean temperature of a temperature distribution from the differential image and calculating a t

Abstract: A portable unit indicates the precise time to close a fireplace damper door. The unit comprises a housing including a power source, and an electronic circuit, and an external heat sensor. The arrangement is such that the heat sensor is placed near the firebox and senses that a fire has been lit by the heat given off. The electronic circuit then stores this information and waits until the heat is no longer present. At this time, a fire extinguished indication is displayed, and a time delay circuit activated. If a fire is restarted before the delay circuit times out, the fire extinguished status is cleared and the process started over. If a fire is not restarted, and the delay circuit does time out, then a audible indication warns that the fireplace damper can now be manually closed to save energy.

Abstract: A method and apparatus multiplexing multiple alarm and head type values in a peripheral fire alarm device includes a head component for sensing the presence or absence of smoke or heat and a base component for communicating with the control panel. A communication interface between the base and head components with no more than three connectors for multiplexing the values between the head component and the base component. The control panel stores algorithms particular to each type of head which may be used to determine if an alarm condition exists. Using data received from the peripheral fire alarm device, the control determines which type of head component is currently installed at the base component and selects the correct algorithm.

Abstract: A system and method for establishing an alarm threshold for each member of a plurality of detectors or sensors includes storing a value returned from each detector indicative of a clear air condition. A second value returned from each detector indicative of a test condition is stored. The stored values are combined with a common detector characteristic value to produce a unique alarm theshold for each detector. The determined alarm thresholds can be stored for subsequent use. Subsequently, a value returned from a detector indicating a current ambient condition can be compared to that detector's previously determined alarm threshold. If the currently returned value from the detector exceeds the predetermined alarm threshold, an alarm condition can be indicated.

Abstract: A fire alarm system employs a neural network for obtaining one or more types of fire related information values. A plurality of detection information values are time-serially collected from plural fire phenomenon detectors. The detection information values are signal processed such that a weighting coefficient is assigned thereto in accordance with a relative significance of the detection information value to the desired fire related information value. The various weighting coefficients are stored in advance in a memory. The weighting coefficients stored are established so that the fire related information value for a particular set of detection information values approximates a desired fire related information value.

Abstract: A solid state speed indicator for railroad locomotives is provided with a plurality of indications in addition to speed. These include an acceleration indicator and an overspeed indicator. In addition, the speed indicator is provided with a dual range speed function having at least one particular use in drag operations. A variation of the solid state speed indicator is a retrofit design that replaces the meter movement in existing speed indicator equipment with a solid state display.

Abstract: Methods for detecting an alarm condition includes repeatedly converting an ambient condition into voltage outputs in detector apparatus repeatedly converting the voltage outputs into a series of actual analog values, polling the series of actual analog values to determine an average analog value, repeatedly comparing the difference between the average analog value and the last actual analog value with a predetermined delta-threshold value and indicating an alarm condition when the difference between the average analog value and the last actual analog value exceeds the delta-threshold value. Methods for detecting an alarm condition further includes repeatedly comparing the average analog value with a maintenance threshold value and indicating a maintenance signal when the average analog value exceeds the maintenance threshold value.

Abstract: A fire detection system includes a color video camera, a frame grabber and a computer processor operative to store and examine a series of image frames of the viewed area. Ultraviolet and infrared detectors produce event signals when energy received exceeds predetermined thresholds. The processor then rapidly evaluates the images from the camera to determine bright area objects, their location, edge profile, edge flicker, stationarity and spectral characteristics as well as spectral flicker to confirm a fire event. Finally, the size of a confirmed fire image is measured as a final criterion for the release of fire suppressant material, either in a limited zone within which the fire is located or within the entire facility.

Abstract: A power supply control device is provided in a fire alarm system having terminals such as fire detectors and/or repeaters with comparators to detect abnormalities such as fire or an operating status of controlled apparatus, and is equipped with a reference voltage supply a source to supply reference voltage to the comparators, and a power supply control to allow the reference voltage to be supplied to the comparators only during the detecting time.

Abstract: A fire alarm system in which an analog type sensor (3) is connected to a transmission line (2) from a receiver (1) and in which one or more on-off type sensor (7) located in the same monitor area (14, 15, 16) as that in which the analog type sensor (3) is provided is connected to a signal line (6) led out from the analog type sensor (3). The analog type sensor (3) is provided with a fire detection circuit (12) for detecting a fire signal from the on-off type sensor (7) and a transmission control circuit (11) for transmitting its own analog detection data and fire detection data from the fire detection circuit (12) to the receiver (1).

Abstract: Temperature sensors are located inside drive chambers where disk drives are located to signal an overheating condition. An overheating condition triggers external alarms and produces an interrupt signal to the disk drive controller, which, in turn, alerts the operating system. If the operating system does not comprehend the problem and take the appropriate action, the controller shuts down the disk drives after a certain period of time.

Abstract: An arrangement in a range, a cooking hob or the like having at least one electrically heated hot plate (11) and/or oven, comprising a manually operable setting system (13) for the setting of a desired power or temperature for the hot plate or the oven. A detecting system (15) is arranged to detect changes in the setting of the setting system. A timing system (16 ) co-operates with the detecting system (15) to be activated by the latter. A switching system (17,26) co-operates with the timing system (16) to disconnect the power to the hot plate (11) or the oven on the reaching of an end time determined by the timing system, said timing system being reset each time the detecting system (15) is activated and then operated to start counting towards the predetermined end time.

Abstract: An alarm system to be used with safes is disclosed. A housing is provided adapted to be mounted to the exterior of a safe, particularly a personal home or business safe. A heat sensor is mounted to a shaft that extends from the housing into the safe. The shaft is designed to pass through a preexisting hole found on many commercial available safes. The heat sensor is electronically linked with a control system adapted to sound an alarm when more than a preselected temperature is sensed at the heat sensor. A motion sensor is also mounted in the housing to sense when more than a preselected amount of motion is sensed in the safe.

Abstract: A solar heating device which indicates the proper window covering status for maximum energy conservation. A support structure (18) rests on window sill (16) and suspends two thermistors (22 and 24). One thermistor (22) is supported on the room side of drapery (12) and the other thermistor (24) is supported between drapery (12) and a window (14). When the net heat flow is inward from outside the room, thermistor (24) near window (14) will be warmer than room side thermistor (22). When this occurs, the temperature dependent resistances of thermistors (22 and 24), voltage divider resistances (30 and 32), and a comparator (36) turn on a light emitting diode (28). This indicates that drapery (12) should be opened to let solar radiation in to heat the room. Otherwise, drapery (12) should be closed to conserve the existing heat in the room.

Abstract: The present invention monitors thermocouple data from a semiconductor furnace. The data is checked against a first set of profiles which mimic an intended operational temperature profile for the furnace. If the temperature measured in any zone of the furnace falls outside a first set of maximum and minimum limits fixed by the mimicking profiles, a warning is generated thereby giving operational personnel an opportunity to correct the condition. If the condition remains unchecked and further deviation occurs, a second condition is reached as defined by a corresponding second set of mimicking maximum and minimum profiles. This condition is established as a serious condition which will cause a microprocessor to terminate power supply to the furnace. Otherwise, the quality of the grown crystal would be jeopardized; or sufficiently excessive power would be delivered to the furnace so as to cause its damage or destruction.

Abstract: Temperature data of each picture element output from a infrared camera looking at a scene to be watched is compared with the same data of a previous frame. Temperature data which has changed from the previous frame is input to a histogram operator having a region defined by the temperature change and quantity of the picture elements. When the quantity of picture elements in the defined region exceeds a threshold level, it is recognized that a certain object having considerable temperature change and size has been detected. Thus, a signal is output to trigger an alarm system, or to sustain circulating frame memories which have recorded the previous scenes so that the scenes of visible light as well as the temperatue patterns for frames before, on, and after the trigger signal can be reproduced as visual images of a display screen.

Abstract: A fire detector assembly comprises a base (1) and a sensor (5) adapted to fit the base. The base (1) is provided with passive means, such as pins (6) or contacts arranged in a pattern to represent an address of the detector. When the sensor (5) is fitted to the base (1), reading means in the sensor reads the address code and thereby conditions the sensor to receive appropriate signals from a control unit.

Abstract: In refrigerator tractor/trailer vehicles, a data acquisition module is connected with one or more temperature sensors adapted for measurement of the temperatures within the trailer and may be connected with one or more distance sensors and "door open" sensors located in the trailer. Such a data acquisition module preferably comprises a microprocessor and random access memory connected with a plurality of sensors and adapted to acquire stored data on temperatures within the trailer and further connected with clock means to provide time data associated with the temperature data. In such systems, a control and display module, which comprises a separate portable control and display unit, can provide temperature data and distance data to the vehicle operator, warnings to the vehicle operator if the temperature of the trailer approaches unacceptable limits, warnings during backing of the trailer of impending collision with an object and warnings if the trailer doors are opened without authority.

Abstract: For the purpose of effecting the thermal control of a heating apparatus the temperature is allowed to rise to a value lower than a predetermined maximum temperature (TM), whereupon, after stopping the heating, the temperature is allowed to rise through thermal inertia until the aforesaid maximum temperature (TM) is substantially reached, the difference (E) between said maximum temperature and the temperature (TC) at which heating is stopped being determined in dependence on the profile of the temperature rise curve during the heating period.Utilization in particular in cooking utensils.

Abstract: A soldering apparatus comprises at least one soldering iron (19) with a heating element (21) and a regulating circuit including a temperature sensor (22) for regulating the working temperature of the soldering iron (19) to a predeterminable desired value (51). The apparatus is characterized by a circuit (45) connected to the soldering unit (19) which at least temporarily stores values corresponding to a time-dependent temperature plot for the soldering iron (19), and also by a monitoring circuit (14) which is connected to the memory circuit. The monitoring circuit monitors during the operation of the soldering iron, from the stored values for the temperature plot, determines whether the temperature undergoes an excursion beneath or above predeterminable upper and lower temperature limits (52, 53) and initiates an alarm signal when the duration of the excursion exceeds a predetermined value.

Abstract: An alarm system for warning of a creosote chimney fire hazard, having both means to produce a visible alarm when the creosote temperature is nearing the creosote flash point, and means to produce an audible alarm when light from actual ignition of a creosote fire is detected. The invention also provides means to discriminate against detection of wood fire light, to minimize false alarms.

Abstract: A power controller system for providing electrical power to a multiplicity of loads at outputs thereof under direction of a plurality of input controllers operating a corresponding plurality of output energization means with the controllers capable of having different output states in response to differnt system input signals, the controller having selected common components for forcing selected ones of said input controllers to terminate power to corresponding loads. Current sensing means upsetting current balances in bipolar transistors are used to sense beyond-limit currents.

Abstract: A two-stage gas furnace control system automatically shifts into a high fire only mode if, in two consecutive low fire heating cycles a limit switch is tripped to indicate that a gas valve is stuck in a high fire condition. In this way, continued operation is allowed to proceed in a safe manner. Provision is also made to lock out the system from further operation if, while in the high fire only mode, the limit switch is tripped in a predetermined consecutive number of cycles or if, while in a preemptive low fire only mode, the limit switch is tripped.

Abstract: A fire alarm system of the present invention is adapted to compute an approximation equation based on the detection data from a detector or detectors such about a smoke density, a temperature, a gas concentration, etc. and predictively determine a fire based on the approximation equation. The system including computing section for computing an approximation equation approximating a change in the physical phenomenon related to the occurrence of a fire which is output from the detector or detectors, sequentially sampled and stored and for computing a future value of the phenomenon estimated from the approximation by using a predetermined number of the data stored in a storing section. The future vale is compared with a data value preliminarily set in association with the fire alarming and an alarm is generated when the relation therebetween is not within a predetermined range.

Abstract: A remote temperature sensing and warning system for a temperature controlled vehicle comprising a remote temperature sensing unit for measuring the temperature in the transport container and transmitting the temperature signal within a repeating time frame through the existing vehicle wiring to a remote receiver; the receiver decoding and converting the signal into a displayable form to continuously display the current temperature of the transport container; the receiver further detecting out of range temperatures and signal transmission errors and providing visual and aural alarms therefrom.

Abstract: An air condition monitor unit for monitoring the temperature and/or relative humidity of the ambient air. It comprises an air temperature sensor and a relative humidity sensor, and a plurality of memory means capable of retaining set values of respective thresholds comprising the maximum and minimum acceptable values of air temperature and relative humidity. Membrane switch means are connected to the plurality of memory means, operation of which switch means changes a set value retained in the plurality of memory means. Further membrane switch means are connected to the first switch means and the plurality of memory means, successive operation of which further switch means changes the memory means for the time being addressed by the first switch means from memory means to the next in a predetermined cycle.

Abstract: A refrigerator control for operating a refrigerator which may experience an abnormal temperature condition due to operation in low ambient temperatures includes a temperature sensor for sensing the temperature of a portion of a refrigerator compartment in order to detect an abnormally low temperature in another portion of the compartment. If the compartment temperature at the end of a predetermined length of time since cooling was last supplied to the compartment is below a predetermined value, then an abnormal condition is assumed to exist and corrective action is taken to eliminate the abnormal condition. A preferred form of corrective action is to prevent compressor re-energization until the compartment temperature reaches a second predetermined value.

Abstract: A method and apparatus features a system for automatically monitoring the operating environment and other physical conditions around and in which a host computer system operates. Sensors located around a computer system, including inside equipment cabinets and under the floor where cabling and air are ducted, are used to collect data that is frequently and periodically collected and stored along with an indication of the time and data of collection. The stored data is checked against a list of environmental parameters for the location of each sensor and an indication given when measurements indicate an environmental condition is outside discrete limits and rates of change of conditions. The stored parameters may be changed at any time from a console of the computer system.

Abstract: A fire condition detection and control system for use with air moving and filtering units. The system includes one or more remote fire condition detection units, which sense heat or smoke and, upon such sensing, transmit a signal indicative of an alarm condition to one or more air moving and filtering units located within a containment area. The transmission is by wireless radio frequency transmission and/or a wired transmission line or cable. The air moving and filtering units detect the alarm condition and disconnect power to the blower motor of the air moving and filtering unit. The receiver and control circuitry may be integral with the air moving and filtering unit, or may be part of a separate control unit that plugs into conventional air moving and filtering units.

Abstract: A temperature control system for cooking apparatus, for example, a fryer using cooking oil or shortening which is heated by a suitable heating element. The cooking apparatus has different modes of operation including start-up mode, idle mode and cooking mode. Overshoot to a temperature above the setpoint temperature is limited during start-up mode, idle mode and cooking mode with the apparatus having different temperature control characteristics based on the mode of operation and adapting variable parameters to achieve optimum temperature control accuracy.

Abstract: A detecting system and a detector which includes an analog sensor for sensing a change in a quantity of an environmental phenomenon, processes a signal corresponding to a detection level output from said analog sensor to detect a change in the environmental phenomenon, in which the detecting sensitivity of analog sensor may be changed between a plurality of sensitivity levels according to the quantity of the phenomenon.

Abstract: A device in a motor vehicle for indicating the outside temperature has a speed sensor in addition to an outside-temperature sensor. The device has a memory for storing a detected temperature when a speed signal drops below a threshold value. The current temperature is then displayed if it is less than the stored detected temperature plus a pre-determined amount; otherwise, the stored detected temperature is displayed. When the vehicle speed rises above a second threshold value, a delay time determiner determines the delay time dependent on the vehicle speed, and a time delay is activated. The time delay causes the indicator to display the current temperature upon expiration of a period of time equal to the delay time following the activation of the time delay.

Abstract: A temperature control signal (S.sub.1) responsive to a target temperature is biquadrated (S.sub.1.sup.4) to produce a power control signal. A power supply unit supplies electric power to one or more radiant heat sources on the basis of the power control signal, whereby an object such as, for example, a wafer is heated by radiant energy from the one or more radiant heat sources. The wafer temperature is proportional to the biquadrative root of the radiant energy in accordance with the well-known Stefan-Boltzmann's law, whereby the wafer temperature correctly follows a predetermined time-dependent target temperature variation over time.

Abstract: A temperature sensor located at a region being monitored controls an output switch that in one position when ambient temperature is below a predetermined temperature applies current to only a first loop circuit and in another position when ambient temperature is at or above the predetermined temperature applies current to only a second loop circuit. Currents in the first and second loop circuits are measured by ferrods to determine whether an over-temperature condition at the region monitored has taken place. An alarm circuit connected to outputs of the ferrods generates an alarm signal in response to a negative transaction of current in the first loop circuit or a positive transition of current in the second loop circuit. A failure in either loop circuit accordingly is insufficient to disable the system. A solid state timer periodically opens the second loop circuit to repeat the alarm signal when the second loop circuit is closed until corrective action is taken.

Abstract: A temperature measuring apparatus has temperature detecting means for detecting a temperature and producing a signal representative thereof, an A/D converter for converting the signal into a digital output signal, a memory for storing as temperature data the output signal of the A/D converter, read-out means for reading out corresponding temperature data from the memory and applying it to a processor, and wait means for setting a wait state by the read signal from the processor until the A/D conversion of the A/D converter is completed.

Abstract: A system, utilizing an analog pulsed signal, is for monitoring the condition of a system, by way of illustration, a multi-circuit electrically heat-traced substrate. The system senses the temperature of the substrate at the end of a heat traced circuit, converts the temperature to a pulsed signal, and drives the pulsed signal along the heat tracing to the control and distribution panel for the heat tracing in direct opposition to the AC which powers the heat tracing. A receiver converts the pulsed signal to a digital temperature read-out. Utilization of an analog pulsed signal enables the system to be used in a multi-circuit system without interference or signal mixing from adjacent circuits.

Abstract: A mechanical four wheel drive tractor having a solenoid valve which is de-energized to effect engagement of drive to the front wheels in a predetermined operational mode. Normally, the valve is controlled by an operator switch but when the engine is overloaded and exhaust gas temperature rises, a thermal sensor breaks the circuit to the solenoid valve so that four wheel drive is automatically engaged. This action is restricted to a low gear range by a switch linked to the mechanism selecting between the low range and a high range. Restriction to a low gear range prevents unwanted automatic four wheel drive engagement from occuring in other gear ranges without regard to vehicle speed. Automatic engagement of four wheel drive reduces the overload on the transmission.

Abstract: A temperature control apparatus for controlling, e.g., a fixing heater of a copying machine has a fuse resistor connected to the fixing heater through a power relay, a thermistor for detecting the surface temperature of a fixing roller heated by the fixing heater, abnormality timers for counting the ON time of the fixing heater and having different preset counts corresponding to different modes of the copying machine, and a control circuit for disconnecting the fuse resistor when the output from the thermistor indicates overheating or the ON time of the heater exceeds the preset count of the timer. Overheating of the heater is prevented with high reliability.

Abstract: A power control system for operating a heating element in a cooking appliance in response to the selection of one of a plurality of user selectable power settings. Approximate heating element temperature information is provided by a heater energy counter. Each power setting has associated with it a corresponding steady state power level and a corresponding predetermined steady state energy count. The steady state energy count is approximately proportional to the steady state operating temperature of the heating element when operated at its corresponding steady state power level. The energy counter is selectively incremented and decremented to approximately track the heating element temperature when the count is respectively less than or greater than the steady state count for the applied power level. At least certain ones of the power settings have corresponding minimum threshold counts less than the steady state counts and maximum threshold counts greater than the steady state counts.

Abstract: An analog fire detecting system in which a plurality of sensors produce analog data corresponding to a physical state such as temperature, smoke density, etc. relevant to a fire condition. The values of such analog data are compared with a predetermined threshold level, and if the threshold level is exceeded the analog data is transmitted to a central station in response to a polling signal therefrom. A CPU in the central station determines, from the analog data from the sensors, if there is a possibility of a fire and if so makes a predictive calculation of the remaining time until a fire condition will be reached. An alarm is given when such predicted time falls below a preset interval.

Abstract: A circuit for indicating when recalibration of an electrical sensor is necessary includes an analog driving circuit adapted to be coupled to the sensor, and an analog indicating device coupled to the analog driving circuit for indicating when the sensor should be recalibrated. The analog driving circuit provides a signal proportional to the current received from the electrical circuit. The indicating device is responsive to the output from the analog driving circuit and provides an output which is a function of both the sensor output and the elapsed time that the sensor has been operated.

Abstract: An improved fire alarm system utilizes receiver and fire detecting terminals connected thereto through a signal transmission line comprising two wires. The fire detecting terminal operates on two mode, one being a contact-closure mode of transmitting to the receiver a level signal whether or not a significantly higher fire-indicative quantity is detected, and the other being intelligent mode of transmitting a digital signal indicative of the sensed quantity in the form of a superimposed signal upon the level signal in answer to the instruction from the receiver for precise and convenient analysis thereof in determining fire presence on the side of the receiver. The fire detecting terminal includes a comparator having its own threshold with which the value of the sensed analog quantity is compared for providing the level-shifted signal when the sensed analog quantity has a level higher than the threshold, notifying fire presence independently of the intelligent mode.

Abstract: The present device includes a resistor network wherein the values of the resistors are chosen such that the heat generated by current passing through the resistors will be substantially equal to heat generated at a semiconductor junction which is to be cooled. The present device further includes a heat sink which is substantially identical to the heat sink employed to withdraw heat from the semiconductor junction to be cooled. Accordingly, the present device provides heat which is identical to the heat generated at the semiconductor junction and which heat remains ambient to the semiconductor junction to be cooled. The present device further includes a sensor which converts temperature to an electrical signal and which is located substantially in the center of the resistor network and at a distance from the heat sink that approximates the position of the semiconductor junction from its heat sink.

Abstract: A method and apparatus for protecting a turbine from undesirable temperature and pressure variations wherein an acceptable range of actual pressure and temperature variations is established, a first alarm signal is generated only if the acceptable range is exceeded by actual temperature or pressure, a second signal is established representing an acceptable rate of change of said actual pressure or temperature and a second alarm is generated if the actual rate of change of pressure or temperature exceeds the acceptable range of pressure or temperature whereby the second alarm signal is produced only when the first alarm signal is generated. In addition, a third signal is established representing a maximum rate of change of pressure and a third alarm signal is generated if the actual rate of change of pressure or temperature exceeds the maximum rate of change of pressure or temperature whereby the third alarm signal is produced only when the first alarm signal is generated.

Abstract: A process is provided for detecting if a temperature sensor (18) is correctly located in a heating conduit at a point that is remote from the heater (28). Power is applied to the heater (28) in a predetermined manner. The change in the temperature sensed by the temperature sensor (18) is observed. If the temperature sensed by the temperature sensor (18) has changed in a certain manner, a signal is provided indicating that the temperature sensor (18) is located correctly. If, during observation, the temperature sensed has not changed in the certain manner, an alarm signal is provided.

Abstract: A device for monitoring environmental exposure includes an element whose electrical properties change, in a predetermined way, in response to the environmental exposure. The element may be part of a tuned circuit or of a shield for a tuned circuit. In either case, when the tuned circuit is interrogated, preferably by an r.f. or microwave signal, it emits a signal whose intensity depends on the electrical properties of the element. Thus, an incremental environmental exposure can be measured by a change in the signal intensity. The device is particularly useful for monitoring the condition of perishable materials, because it can be located with the perishable inside a packaging material during both storage and interrogation.