First-out annunclator having input and supply control of indicator switching means

Claim 1

A FIRST-OUT MONITORING ANNUNCIATOR SYSTEM COMPRISING A PLURALITY OF DEVICES TO BE MONITORED, A D.C. SUPPLY CIRCUIT, A PLURALITY OF INDICATING CIRCUITS CONNECTED ACROSS SAID SUPPLY CIRCUIT, EACH INDICATING CIRCUIT HAVING A GLOWDISCHARGE TUBE CONNECTED THEREIN, EACH TUBE BEING A TRIODE HAVING A STARTER ELECTRODE, THE ANODE-CATHODE CIRCUIT OF EACH TUBE BEING SERIES-CONNECTED IN THE RESPECTIVE INDICATING CIRCUIT, A CONTROL CIRCUIT CONNECTED TO SAID SUPPLY CIRCUIT, AND A PLURALITY OF SENSING SWITCHES, EACH ASSOCIATED WITH A RESPECTIVE DEVICE TO BE MONITORED AND ADAPTED TO BE ACTUATED IN RESPONSE TO OCCURRENCE OF AN ABNORMAL CONDITION IN THE RESPECTIVE MONITORED DEVICE, EACH SENSING SWITCH BEING CONNECTED BETWEEN SAID CONTROL CIRCUIT AND THE STARTER ELECTRODE OF A RESPECTIVE TUBE, AND MEANS RESPONSIVE TO ACTUATION OF ANY ONE OF THE SENSING SWITCHES AND RESULTANT RESPONSE OF THE RESPECTIVE TUBE FOR CONCURRENTLY REDUCING THE VOLTAGE APPLIED TO ALL THE OTHER TUBES AND DISCONNECTING SAID CONTROL CIRCUIT FROM SAID SUPPLY CIRCUIT WHEREBY ACTUATION OF ANY OTHER TUBE IS PRECLUDED EVEN THOUGH THE SENSING SWITCH THEREFORE SHOULD BE ACTUATED.