| 摘要 |
A safety device for an industrial boiler (CHA) including electromechanical relays (RE<SUB>n</SUB>, RS), which are connected in series in order to form an electromechanical safety chain (CH 1 ), and at least one shunt relay (RT<SUB>n</SUB>) which is normally open and mounted in parallel to one of the electromechanical relays (RE<SUB>N</SUB>). The shunt relay is controlled by an automaton (AP 1 ) so that it is closed during a time delay. The shunt relay (RT<SUB>n</SUB>) is provided with a contact that is connected to an electronic circuit (CE<SUB>n</SUB>) and said electronic circuit (CE<SUB>n</SUB>) opens an electromechanical relay (RS) which is mounted in series in the safety chain when the shunt relay (RT<SUB>n</SUB>) is closed for longer than the time delay. Given the arrangement, in the event of an automaton failure, the time delay is ensured by the electronic circuit so that a satisfactory level of safety is guaranteed in relation to the installation.
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