Abstract: Enhanced inserts are formed having a cylindrical grip and a protrusion extending from the grip. An ultra hard material layer is bonded on top of the protrusion. The inserts are mounted on a rock bit and contact the earth formations off center. The ultra hard material layer is thickest at a critical zone which encompasses a major portion of the region of contact between the insert and the earth formation. Transition layers may also be formed between the ultra hard material layer and the protrusion so as to reduce stresses formed on the interface between the ultra hard material and the protrusion.

Abstract: Method for purging a furnace comprising a closable processing tube defining in its interior a closable, processing space, a purging gas being flowed along the outer surface of the processing tube separated from the processing gas flow inside the processing tube, wherein said processing gas flow comprises a gas being reactive with air at elevated temperature and said purging gas comprises an inert gas. A furnace assembly for realizing this method is proposed comprising a controller for controlling force connected in a conduit connected to a source of reactive and inert gas respectively. This controller is realized such that only after placing the closure of the processing chamber in the closing position the valve in the supply conduit for reactive gas can be opened and said closure can only be removed from said closing position after said valve in supply conduits for reactive gas has been closed.

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: Discharge system for a reactor, such as a furnace. The discharge system comprises a collection duct, to which a number of discharge lines are connected, each discharge line in turn being coupled to an installation, such as a furnace. In order to keep the reduced pressure at the location of a furnace of this nature as constant as possible, it is proposed to provide a valve at the location of the reactor, which valve adjusts an opening between the discharge line and atmosphere in a controllable manner. In this way, a controlled reduced pressure can be maintained at the location of the valve, i.e. at the outlet from the reactor.