Leak detector for heat exchangers in gas insulated electric apparatus

Claim 1

A GAS INSULATED ELECTRIC INDUCTION APPARATUS INCLUDING A SEALED ENCLOSING CASING CONTAINING A HEAT EVOLVING DEVICE AND A DIELECTRIC GAS, MEANS INCLUDING A PUMP WITHIN SAID CASING FOR CIRCULATING SAID GAS THROUGH A PERDETERMINED PATH TO COOL SAID DEVICE, A LIQUID FILLED HEAT EXCHANGER MOUNTED UPON A WALL OF SAID CASING AND EXTENDING INTO SAID CASING IN THE PATH OF CIRCULATION OF SAID DIELECTRIC GAS, SAID HEAT EXCHANGER COMPRISING A PLURALITY OF PARALLEL TUBES HAVING AT EACH END THEREOF A PAIR OF JUXTAPOSED INNER AND OUTER TUBE SHEETS IN SPACED RELATION AND A LIQUID HEADER, SAID HEADERS EACH INCLUDING THE OUTER TUBE SHEET AT EACH END OF SAID HEAT EXCHANGER, MEANS FIXEDLY MOUNTING ONE OF SAID INNER TUBE SHEETS TO THE WALL OF SAID CASING IN FLUID TIGHT RELATION THEREBY TO SUPPORT SAID HEAT EXCHANGER WITH THE SPACE BETWEEN THE PAIR OF TUBE SHEETS AT THE OUTER END OF SAID HEAT EXCHANGER BEING OUTSIDE SAID CASING AND VENTED TO ATMOSPHERE, SAID TUBES EXTENDING INTO SAID CASING WITH THE INNER ENDS OF SAID TUBES BEING FREE TO MOVE AS SAID TUBES EXPAND AND CONTRACT, MEANS ENCLOSING THE SPACE BETWEEN THE PAIR OF TUBE SHEETS AT THE INNER END OF SAID TUBES THEREBY TO FORM A CLOSED LEAKAGE COMPARTMENT FOR DIELECTRIC GAS AND COOLING FLUID, AND A DRAINAGE TUBE EXTENDING FROM SAID LEAKAGE COMPARTMENT TO THE OUTSIDE OF SAID CASING.