Abnormal fuel pressure cut off and purge system

Claim 1

IN FORCED DRAFT AIR-GAS BURNERS UTILIZING A MAIN GAS SUPPLY LINE INCLUDING A PRESSURE RESPONSIVE MANUAL RESET MAIN GAS GALVE, A PRIMARY AIR SOURCE, AND A PILOT GAS SUPPLY LINE INCLUDING A MANUAL RESET PRESSURE RESPONSE PILOT VALVE A SAFETY SYSTEM COMPRISING: MEANS CONNECTING SAID PRESSURE RESPONSE PILOT VALVE TO BE RESPONSIVE TO AIR PRESSURE OF SAID PRIMARY AIR SOURCE TO PERMIT SAID PILOT VALVE TO BE MANUALLY OPENED AND PERMIT GAS FLOW THERETHROUGH INTO SAID PILOT GAS SUPPLY LINE; MEANS CONNECTING SAID PRESSURE RESPONSIVE MAIN GAS VALVE TO BE RESPONSIVE TO PRESSURE IN SAID PILOT GAS SUPPLY LINE AND ALSO RESPONSIVE TO AIR PRESSURE FROM SAID PRIMARY AIR SOURCE TO PERMIT OPENING OF SAID MAIN GAS VALVE AND ESTABLISH GAS FLOW IN SAID MAIN GAS SUPPLY LINE, A HIGH GAS PRESSURE SENSING VALVE MEANS CONNECTING SAID HIGH GAS PRESSURE SENSING VALVE TO BE RESPONSIVE TO UNSAFE HIGH PRESSURE IN SAID MIAN GAS SUPPLY LINE TO SHUT-OFF AIR PRESSURE FROM SAID PRIMARY AIR SOURCE TO SAID MAIN GAS VALVE; SAID MAIN GAS VALVE THROUGH ITS CONNECTING MEANS ARRANGED TO BE RESPONSIVE TO SHUT-OFF OF AIR PRESSURE FROM SAID PRIMARY AIR SOURCE TO CLOSE SAID MAIN GAS VALVE AND SHUT-OFF SUPPLY OF GAS THROUGH SAID MAIN GAS SUPPLY LINE; A LOW GAS PRESSURE SENSING VALVE MEANS OPERABLY RESPONSIVE TO UNSAFE LOW PRESSURE IN SAID MAIN GAS SUPPLY LINE TO SHUT OFF AIR PRESSURE IN SAID PRIMARY AIR SOURCE TO SAID PILOT VALVE TO CAUSE THE LATTER TO CLOSE AND SHUT OFF SUPPLY OF PILOT GAS LINE PRESSURE TO SAID MAIN GAS VALVE AND THEREBY CAUSE SAID LATTER VALVE TO CLOSE SAID SHUT OFF SUPPLY OF GAS TO SAID MAIN GAS SUPPLY LINE.