Leak detector for fluid conductors

Claim 1

A LEAK DETECTOR FOR FLUID CONDUCTORS INCLUDING A HOUSING ADAPTED TO BE MOVED LONGITUDINALLY THROUGH A FLUID CONDUCTOR, MEANS ON TEH HOUSING FOR SEALING OFF BETWEEN SAID HOUSING AND THE INNER SURFACE OF THE CONDUCTOR AND PROVIDING A CHAMBER THEREBETWEEN WHEREBY THE CHAMBER HAS A PORTION THEREOF FORMED BY TEH CONDUCTOR INNER SURFACE AND COMMUNICATES WITH LEAKS IN THE CONDUCTOR, A PASSAGE IN SAID HOUSING ESTABLISHING COMMUNICATION BETWEEN SAID CHAMBER AND CONDUCTOR WHEREBY THE PRESSURES THEREIN ARE SUBSTANTIALLY EQUAL, A SECOND PASSAGE IN SAID HOUSING COMMUNICATING WITH THE CONDUCTOR, EACH PASSAGE HAVING AT LEAST A PORTION OF SMALL AREA CAPABLE OF CONTAINING ONLY A SMALL VOLUME OF FLUID, FLOW SENSITIVE MEANS IN EACH PASSAGE PORTION OF SMALL AREA RESPONSIVE TO SMALL VOLUMES OF FLOW, RECORDING MEANS, AND AN ELECTRICAL BRIDGE CIRCUIT INCLUDING A POTENTIAL SOURCE AND A PAIR OF ARMS WHICH CONNECT THE FLOW SENSITIVE MEANS TO THE RECORDING MEANS.