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US 4,700,040 AGranted
Radiant brazing temperature sensing apparatus and process
AssigneeWestinghouse Electric Corp.
InventorJohn M. Driggers
Life of this patent
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AssigneeWestinghouse Electric Corp.
InventorJohn M. Driggers
Estimating the term…
Both an apparatus and a process for accurately applying a correct amount of brazing heat to a conduit are disclosed herein. The apparatus generally comprises a mandrel including an electrical resistance wire heating element and a heat sensor for sensing the temperature of the inside walls of the conduit which were heated. The mandrel is preferably formed from a refractory material, and the heat sensor is located beneath the surface of the mandrel in order to insulate it from heat radiated from the electrical resistance wire wound about the mandrel body. The mandrel further includes an opening in the portion of the mandrel which surrounds the heat sensor in order that the sensor may be selectively exposed to a section of conduit to which heat was applied by sliding the mandrel to a position which aligns the opening with the wall of the heated conduit. The temperature of the conduit may then be determined as a function of the radiant heat received by the heat sensor. The invention is particularly useful in producing high quality braze joints between reinforcing sleeves inserted within damaged heat exchange tubes of a nuclear steam generator since the heat sensor allows the operator to determine whether or not a proper amount of brazing heat was applied to the sleeve/tube configuration.
A process for brazing a sleeve circumscribed by a ring of brazing material to the inside wall of a tube, comprising the sequential steps of:
A process for brazing a sleeve circumscribed by a ring of brazing material to the inside walls of a tube with a heater assembly formed from an elongated mandrel havng a heating element in the form of an electrical resistance wire coiled about the central section of the mandrel, a heat sensor for determining the temperature of a longitudinal section of the sleeve exposed to the heating element, means for insulating the heat sensor from the heat radiated from the heating element, and means for placing the heat sensor in thermal communication with the selected heated section of the sleeve including an opening in the insulator means for exposing the heat sensor to heat radiated by the selected heated section of the sleeve, wherein said opening and said heating element are sufficiently longitudinally spaced apart so that said heating element may apply heat to a second selected longitudinal section of the sleeve which is different from the first selected section of the sleeve when said opening is positioned, comprising the steps of:
Dependencies are inferred from the claim text.