Abstract: A flame detection device for detecting a flame caused by a fire, including a light attenuation filter for attenuating 90% or greater of light with wavelengths in a visible to near-infrared band radiated from the flame. The flame detection device further includes an imager for photographing an image of the attenuated light incident thereon, and a processing section for deciding the flame from the image obtained by the imager.

Abstract: A light scattering type smoke sensor comprising a holder with openings embedded with light emitting part and light detecting part respectively, which do not protrude into the smoke detection chamber. The optical axis of light emitting part intersects at a predetermined first angle &agr; in the horizontal direction with the optical axis of the light detecting part at a predetermined second angle &bgr; in the vertical direction. The optical axis of the light emitting part and optical axis of the light detecting part further comprise a configuration angle &dgr; in the range of 90˜120 degrees used as the supplementary angle for the scattering angle &thgr;. Accordingly, the smoke detection part is further constituted in a thin-shaped light scattering smoke sensor which enables the setup of a scattering angle with no directivity in the smoke influx to the smoke detection chamber.

Abstract: A fire heat sensor comprising a high-temperature detecting portion provided with a temperature detecting element which exhibits a fast heat response to a rise in ambient temperature, and a low-temperature detecting portion provided with a temperature detecting element which exhibits a slow heat response to a rise in ambient temperature. The fire heat sensor further comprises a resin member by which the high-temperature detecting portion and the low-temperature detecting portion are integrally formed so that heat energy is transferred from the temperature detecting element of the high-temperature detecting portion to the temperature detecting element of the low-temperature detecting portion. In the fire heat sensor, differential heat sensing is performed based on temperatures detected by the low-temperature detecting portion and the high-temperature detecting portion.

Abstract: A fire sensor comprising a heat detection element for detecting heat from a hot airflow generated by a fire, a sensor main body, and an outer cover, which has a plurality of plate fins protruding from the sensor main body, for protecting the heat detecting element. The plate fins have a predetermined offset angle to a center line passing through the center of the outer cover and are erected approximately perpendicular to the sensor main body.

Abstract: Disclosed herein is a fire alarm system for connecting a plurality of fire sensors to sensor lines, and giving an alarm in response to fire information output from the fire sensor in a line unit. The fire alarm system includes a current modulation section and an address specification section. The current modulation section is used for maintaining a current flowing in the sensor line at a predetermined value for a predetermined time at the time of a fire, and modulating the current in accordance with the inherent address information of the fire sensor. The address specification section is used for sensing fire information by judging whether or not the current has been maintained at the predetermined value for the predetermined time, and also for specifying the inherent address of the fire sensor that issued the fire information, from the modulated state of the current.

Abstract: A fire sensor comprising a baseplate, a temperature detecting element, and a protective case. The baseplate has an outside surface which serves as a heat sensing surface which is exposed to a hot airflow generated by a fire. The temperature detecting element thermally contacts with the inside surface of the baseplate to detect the temperature of the baseplate. The protective case contacts with the radially outer portion of the inside surface of the baseplate to form a hermetically sealed space between itself and the baseplate. The temperature detecting element is confined within the hermetically sealed space. The baseplate has the temperature detecting element in approximately the central portion of the inside surface thereof and also has a shape and a material which meet the condition that the product of the thickness and heat conductivity of the baseplate is 1.1×10−4 (W/K) or less.