Spark gap type of surge arrestor for a d.-c. system

Claim 1

A SURGE ARRESTOR FOR A D.C. CIRCUIT COMPRISING: (A) A PAIR OF SPACED-APART ELECTRODES DEFINING A GAP THEREBETWEEN, (B) MEANS ADAPTED TO ELECTRICALLY CONNECTED SAID ELECTRODES INTO SAID D.C. CIRCUIT, (C) EACH OF SAID ELECTRODES COMPRISING AN ARC-INITIATION PORTION AND FIRST AND SECOND ARC-RUNNING PORTIONS RESPECTIVELY LOCATED AT OPPOSITE SIDES OF SAID ARC-INITIATION PORTIONS, (D) MEANS FOR CAUSING AN ARC TO BE ESTABLISHED BETWEEN SAID ARC-INITIATION PORTIONS IN RESPONSE TO A VOLTAGE SURGE OF A PREDETERMINED MINIMUM MAGNITUDE APPEARING ON SAID D.C. CIRCUIT, (E) MEANS FOR PROPELLING AN ARC ESTABLISHED BETWEEN SAID ARC-INITIATION PORTIONS AS A RESULT OF A LIGHTNING SURGE ALONG SAID SECOND ARC-RUNNING PORTIONS DURING THE PASSAGE OF LIGHTNING DISCHARGE CURRENT, (F) MEANS FOR PROPELLING AN ARC CARRYING POWER FOLLOWER CURRENT AFTER PASSAGE OF SAID LIGHTNING DISCHARGE CURRENT ALONG SAID FIRST ARC-RUNNING PORTIONS IN A DIRECTION AWAY FROM SAID ARC-INITIATION PORTIONS, (G) AND MEANS FOR DEVELOPING AS SAID POWER FOLLOW CURRENT ARC MOVES ALONG SAID FIRST ARC-RUNNING PORTIONS AN INCREASING ARC VOLTAGE THAT FORCES THE POWER FOLLOW CURRENT TOWARD ZERO.