Abstract: A ceramic valve assembly is housed in a recess formed in a metal pipe and is supported via gaskets by the metal pipes. Each gasket has a larger coefficient of linear expansion than that of the metal pipe. A clearance generated due to the thermal expansion difference between the metal pipe and the ceramic housing is absorbed by the large thermal expansion of the gasket so that no play is generated between the ceramic valve assembly and the metal pipe and the sealing force is maintained. Each gasket has beads constructed of spring material. An excessively large load does not act on the ceramic assembly because the beads are deformed to absorb the load.

Abstract: Method and device for supplying electric current to ceramic heaters comprising heating resistors embedded in ceramic sintered bodies, being characterized in that direct current is supplied from a direct current supply circuit as the first current supply step and the direction of the direct current supplied to the heating resistors at the first current supply step is reversed by a switching circuit or alternate current is supplied as the second current supply step in order to eliminate or considerably reduce cracking of the ceramic sintered bodies of the ceramic heaters when the heaters are repeatedly used for a long time at high temperatures.