A collar for supporting and positioning a diffusion tube in a furnace used in the manufacture of semiconductors, integrated circuits and the like, is disclosed. The collar has a resilient core and an outer cover enclosing the core. The core and the cover are made of materials which readily withstand the normal operating temperatures of the furnace. The collar is dimensioned to tightly fit around a circumference of the diffusion tube, and to fit within an aperture provided in a support block of the furnace. The collar permits precise positioning of the diffusion tube relative to a helical heating coil provided in the furnace.

A device for measuring in situ the temperature of an annular elastomeric seal is provided which comprises, in a preferred embodiment thereof, an annular elastomeric seal formed of two annular halves, a thermocouple embedded in said seal near the interface of said annular halves, a sleeve having one end molded to one of said halves for supporting and protecting the thermocouple leads and for conducting said leads external of the housing or fixture incorporating said seal.

A method for producing phyllosilicate-intercalation compounds with an increased expansion volume and/or a modified onset temperature includes intercalating intercalated compounds in native, expandable phyllosilicates, wherein the native phyllosilicate is subjected to ion exchange with at least one cationic surfactant and, at the same time or in a further step, at least one organic intercalation compound is intercalated in the phyllosilicate, with the proviso that the intercalation of dimethylformamide, chloroform, dimethylacetamide, toluene and dimethylsulfoxide can take place also without a prior ion exchange.

A well packer has a mandrel assembly with a tubular packing element supported thereon between upper and lower support members that are arranged to telescopically compress the packing element upon setting of the packer. The packer is constructed to retain the mandrel assembly in a telescopically retracted position compressing the packing element longitudinally until released. The tubular packing element has a quantity of loosely packed, heat resistant, compressible material of a substantially inorganic composition. Upon setting of the packer, the packing material is compressed to a tightly compacted configuration in order to establish a fluid tight seal between the mandrel assembly and the well bore. Because of the configuration of the tubular packing element, this packer is suited for operation in wells where substantially high temperatures are prevalent.

An asbestos-free gasket is produced from a composition which comprises from about 5% to about 20% of an organic latex binder, from about 5% to about 35% of a cellulosic fibrous material, from about 0% to about 30% of mineral wool, at least about 50% of an inorganic filler, and from about 0 to about 5% of a coloring additive. The percentages being on a dry weight basis of the gasket. The organic materials are present in an amount no greater than 40% of the total dry weight of the gasket and preferably no greater than 30%. The inorganic filler is an inactive additive, stable at a temperature greater than 1700.degree. F., such as Portland Cement, diatomaceous earth, silicates, carbonates, barytes and mixtures thereof. Preferably the inorganic filler is a mixture of barytes and talc in a ratio of from about 1 to 0, to 3 to 1.