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 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 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: 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 magnet section is constructed by installing a coil (2) on a yoke (1), and an armature (3) is placed facing the attracting surface of this magnet section. Indentations and projections are formed to confer the characteristics of both an opposing type electromagnet and a plunger type electromagnet on the magnetic path portion that faces yoke (1) and armature (3). By doing this, the attractive force characteristics will be uniform, and the operating speed and the holding position of the armature can be set as desired by adjusting the magnetization. Thus, the force of impact can be lessened by deceleration control of the armature, and the impact noise can be reduced. In a further aspect, a thin, single sheet annular, noise-damping waveform spring (6) is attached to the outer edge of the attracting surface of the magnet's yoke (1) or armature (3).