Pilot valve and a system operable in connection therewith

Claim 1

A FLUID-CONTROLLED FIRE ALARM SYSTEM COMPRISING A FIRE DETECTOR RESPONSIVE TO HIGH TEMPERATURES INCIDENT TO A FIRE, A FIRST FLUID-RESPONSIVE AUDIBLE FIRE ALARM DEVICE, A SOURCE OF PRESSURE FLUID, A FLUID CONNECTION BETWEEN SAID SOURCE OF PRESSURE FLUID AND FIRE ALARM DEVICE, MEANS OPERABLE IN RESPONSE TO THE ACTION OF HIGH TEMPERATURE ON SAID DETECTOR FOR RELEASING PRESSURE FLUID FROM SAID SOURCE INTO SAID CONNECTION FOR ACTUATION OF SAID FIRE ALARM DEVICE, A SECOND AUDIBLE FIRE ALARM DEVICE RESPONSIVE TO A FLUID UNDER A PRESSURE GREATER THAN THAT AVAILABLE FROM THE RELEASED PRESSURE FLUID WHILE SAID RELEASED PRESSURE FLUID IS BEING UTILIZED TO ACTUATE SAID FIRST FIRE ALARM DEVICE, A SOURCE OF FLUID UNDER PRESSURE SUFFICIENT TO OPERATE SAID SECOND FIRE ALARM DEVICE, A FLUID CONNECTION BETWEEN THE LATTER SOURCE AND SAID SECOND FIRE ALARM DEVICE, A PILOT VALVE HAVING AN INLET, AND MEANS FOR DELIVERING THE RELEASED FLUID TO SAID INLET WHILE SAID RELEASED FLUID IS OPERATING SAID FIRST FIRE ALARM DEVICE, SAID PILOT VALVE ALSO COMPRISING A NORMALLY CLOSED PRESSURE VALVE IN THE CONNECTION BETWEEN THE LATTER SOURCE AND SAID SECOND FIRE ALARM DEVICE, AND MEANS RESPONSIVE TO THE PRESSURE OF THE FLUID ADMITTED TO SAID PILOT VALVE THROUGH SAID INLET FOR OPENING SAID PRESSURE VALVE AND FOR ADMITTING THEREBY FLUID FROM THE LATTER SOURCE TO SAID SECOND ALARM DEVICE THROUGH THE LAST MENTIONED CONNECTION AT A PRESSURE GREATER THAN THAT AVAILABLE FROM THE RELEASED PRESSURE FLUID AND ADMITTED INTO SAID INLET.