Abstract: A flame and radiation detector system is provided with programmable logic to read the detector and control the detector voltage supply in order to make possible a high counting rate. This makes the radiation detecting system fast and reliable by increasing the signal to noise ratio.

Abstract: In a fire sprinkler system a plurality of physically distributed actuators are connected in a normally balanced bridge circuit. The bridge circuit is impressed with a pulsed measuring voltage thereacross to conserve power. LEDs are connected to the bridge for indicating either normal or unbalanced conditions of the bridge as well as indicating which actuator branch of the bridge is causing unbalance.

Abstract: The present invention relates to a method of and a device for automatically releasing all or a predetermined number of sprinker heads comprised in a fire protection circuit when one of the heads (11) has been released by a local fire or a rise in temperature in the immediate vicinity of this particular head. The invention is based upon a flow detector arranged in the trunk pipe for the fire extinguishing fluid which when said fluid begins to flow through the trunk pipe, i.e. when at least one sprinkler head has opened, closes an electric ignition circuct (17-21, 25-27) which connects pyrotechnical activators arranged at the respective sprinkler heads with an electric ignition function controller (12), whereby the blocking devices at the outlets of the other sprinkler heads are blown away.

Abstract: A method and apparatus for releasing a sprinkler head (1, 2, 3, 5, 6, 7, 8) are disclosed in which a compacted body (14) of fine particles of a material such as antimony is shot by means of a radiation responsive detector (16, 17, 18) and detonator (9, 10, 11, 12, 13) into contact with a hollow glass bulb (4) which normally prevents operation of the sprinkler, thereby shattering the bulb, disintegrating the compacted body and releasing the sprinkler.