Abstract: The treatment chamber in the furnace is delimited by a liner of refractory material. In order to increase the life thereof and in particular to restrict the sensitivity to deposits deposited by the process gas fed through the furnace, it is proposed to make the liner of a silicon carbide material. To seal the furnace chamber, a second liner of quartz material is placed around a liner of this type and the gap between the two liners is flushed.

Abstract: An improved mass flow meter is disclosed for measuring the flow rate of a fluid through a thin walled sensor tube that has the feature of high sensitivity to the temperature of the fluid within the sensor tube. The sensor tube is wound with closely coupled resistance elements of insulated wire. Measurement is accomplished with a conventional bridge connection to the sensor resistance elements. The bridge is designed to remain in balance over a wide range of ambient temperature at a zero flow rate. Fluid flow through the sensor tube upsets the uniform temperature gradient with heat loss being greater upstream so that the balance of the sensor resistance elements installed or coupled to the sensor tube (which elements are heated by a power supply) is progressively upset with increasing flow.