Nittan Company Limited

Seiichi Tanaka

Tetsuo Kimura

Takashi Suzuki

Hiroshi Tanaka

Hirofumi Fujii

Koju Sasaki

Ryukichi Hashimoto

Narimasa Takahashi

Takasi Suzuki

A sensor device of the present invention is capable of surely detecting occurrence of a fire and a type of the fire. The sensor device includes a detection element made of an organic semiconductor element or an inorganic semiconductor element which is varied in characteristic value (i.e., resistance) thereof by both gas produced in a flaming-type fire and a smouldering-type fire and of which a variation in resistance by gas produced in a flaming-type fire is different in polarity from that by gas produced in a smouldering-type fire. A resistance of the detection element is extracted by a resistance extractor and then fed to a resistance decrease discriminator and a resistance increase discriminator, wherein a decrease or increase in resistance of the element is discriminated. An information output circuit outputs a predetermined signal depending on discrimination results provided by the discriminators, to thereby detect occurrence of a fire and/or a type of the fire.

Sensor device, and disaster prevention system and electronic equipment

A fire sensing unit is provided with apparatus which sends out a code identifying the type of sensor apart from transmission of the quantized signals of the analog output of the sensor of the sensing unit. Thus the data processing unit of the receiving unit of a fire detection system including the sensor can be simplified because the receiving unit need not collate the types of the installed sensors with a list of addresses stored therein. Also replacement of sensors can be easily effected since the information regarding the type of sensors is stored in the sensing unit.

Fire detection system

An improved apparatus for detecting environmental disturbances such as the occurrence of a fire, a gas leak or the like, includes a central processing unit and a plurality of terminal detectors, wherein an identification code is assigned to each of the detectors and the central processing unit sequentially calls the detectors in rotation requesting them to transmit thereto the data collected on smoke concentration, gas concentration, temperature or the like. The apparatus is provided with a display unit and a memory. Data collected by each detector concerning on the environmental condition of the place where each detector is installed are stored in the memory in time series. When a signal for data exceeding a fixed reference level is received, a provisional alarm is raised for the operator and the stored data for a limited period of time in the past are displayed. The operator, upon noticing the alarm, reads the displayed data and judges whether a disturbance, a fire for instance, has occurred basing his judgment on his interpretation of the pattern of the past data in the light of the specific characteristics of said detector and the place where the detector is installed, and, when he judges that a disturbance has occurred, he manually issues a general alarm.

Apparatus for monitoring disturbances in environmental conditions

In a polling type surveillance control apparatus for a security system, inherent addresses are assigned to respective terminal devices such as smoke detectors, temperature sensors, gas leakage detectors, fire partitions and smoke dampers. When a self address detector in the terminal device detects a coincidence between the address signal from a central station and a preset self address, the terminal device indicates it has been accessed or energized and power control thereof may also be performed.

Surveillance control apparatus for security system

An environmental abnormality detecting apparatus for detecting abnormality in atmosphere such as heat, smoke, and a gas. A sampling circuit is provided for periodically sampling analog signals from a detector for detecting these phenomena. A quantizer quantizes sampled signals with step levels. An accumulator having a plurality of counters provides different accumulation times corresponding to the step levels. Reliability in accumulation effect is not degraded, and an abnormality signal can be detected in a short period of time when a degree of abnormality is high.

Environmental abnormality detecting apparatus

A photoelectric smoke sensor terminal has an address signal detector for detecting whether or not an address assigned to the terminal coincides with an address represented by an address signal from a main unit. Only when the coincidence signal is supplied to a switch circuit is a photoelectric smoke sensor turned on. The terminal also has an item data memory for supplying item data (e.g. gas leakage and smoke generation data) so that a plurality of item data signals together with an output signal from the sensor can be transmitted on a single transmission line.

Photoelectric smoke sensor terminal

An atmospheric abnormality detection system includes a command discriminator and a display/alarm circuit in each sensor terminal. When the command discriminator receives a coincidence signal from an address comparator, the command discriminator causes an A/D converter to convert an analog sensor output to a digital signal as response data. When an abnormal state display command is transmitted from a main unit to the command discriminator, the command discriminator causes the display/alarm circuit to display information indicating the abnormal state and/or generate an audible alarm.

Atmospheric abnormality detection alarm system

An alarm terminal device has a lower limit voltage generator for generating as a lower limit voltage an analog signal which is produced from a temperature sensor and which is lower than a first predetermined value, and an upper limit voltage generator for generating as an upper limit voltage an analog signal which is produced from the temperature sensor and which is higher than a second predetermined value. At least one additional sensor is provided for generating an analog data signal having a voltage higher than the upper limit voltage or lower than the lower limit voltage so as to indicate any information other than that contained in the analog signal from the temperature sensor. A disconnection or a short circuit of a platinum resistor of the temperature sensor can thus be represented by the analog data signal to be quantized by an analog-to-digital converter employed in the sensor.

Alarm terminal device

A fire alarm system has a main unit and a plurality of sensor terminals in accordance with a polling system. The plurality of sensor terminals are divided into a plurality of groups. When a given sensor terminal of a given group is accessed and transmits digital data as response data indicating a smoke concentration or a temperature to the main unit, and the response data exceeds a first reference value thereby indicating that a fire has broken out, the main unit accesses other sensor terminals of the given group. If some of the response data therefrom exceed a second reference value which is equal to or smaller than the first reference value, the main unit counts the number of such sensor terminals. When the number exceeds a predetermined number, the main unit displays information indicating the existence of a fire.

Fire alarm system

When a receiver supplies both an address signal and a test instruction signal to a given terminal unit, a test voltage generator forming a sensor test circuit of this terminal unit supplies a predetermined test voltage to a corresponding sensor. This sensor generates an analog signal obtained by superimposing the test voltage on the normally detected voltage. The analog signal is A/D-converted, and a resultant digital signal is received by the receiver, thereby allowing a test for operating conditions of any sensor at the site of the receiver. The test voltage generator may generate a plurality of stepwise voltage components to readily check operating characteristics (e.g., overload characteristic) of the sensor.

Sensor test circuit of an alarm system

A temperature sensor has a series circuit of resistors, a gain control switch connected in parallel with one of the resistors of the series circuit, and a reference voltage control switch connected in parallel with a middle resistor of resistors of a reference voltage generation section. The reference voltage and the gain of an operational amplifier are variable so as to change the resolution of the output signal and/or a detected temperature range of the sensor.

Growing community of inventors

Chiba, Japan

Seiichi Tanaka