| 摘要 |
<p>1,059,860. Thermocouples. UNITED KING- DOM ATOMIC ENERGY AUTHORITY. Dec. 10, 1965 [Dec. 15, 1964], No. 51011/64. Heading H1K. At least one of the elements of a thermocouple is formed by pyrolytic deposition from the gas phase on a refractory element. In one embodiment a couple is made by pyrolytic deposition of carbon on a rhenium or ruthenium wire coated except at its tip with beryllia. Alternatively silicon carbide is deposited on an insulated carbon-coated wire. The resulting element may be provided with a protective overcoating of beryllia and a metal sheath, e.g. of molybdenum alone or alloyed with rhenium or ruthenium, or of niobium. The sheath may be in the form of a deposited layer or a preformed tube. An alternative device is provided by depositing silicon carbide on the inside of a metal sheath, inserting a beryllia tube within the coated sheath and then depositing carbon within the tube to form a couple with the carbide layer. A multiple couple, Fig. 4, is formed by inserting an alumina tube 19 coated inside and out with pyrolytically deposited carbon 20, 21 inside a graphite sheath 16, and assembling a graphite rod tipped with pyrolytic carbon 23a through the tube to contact the closed end of the sheath. Couples are thus formed at points 17 and 18. The pyrolytic depositions are carried out at temperatures above those expected in operation, e.g. at 1700-1800‹ C.</p> |
