Abstract: An apparatus for supplying high purity gas comprises a cylinder having a valve with two internal ports. One internal port is used to fill the cylinder while the other is fitted with a unit which removes particulates and impurities from the gas as it leaves the cylinder. The unit comprises an inlet, a first filter for removing coarse particulates, layers of adsorbent and absorbent for removing impurities, and a second filter for removing fine particulates. The purified gas leaves the cylinder via the valve and after passing through a regulator, a flow control device and various lengths of tubing passes through a conventional purifier immediately upstream of the point of use. The apparatus reduces the load on the purifier and hence decreases the frequency at which the purifier has to be recharged. Potentially the apparatus could obviate the need for the purifier altogether.

Abstract: The volume of atmosphere needed to inhibit the ingress of ambient oxygen into the furnace chamber (3) of a continuous heat treatment furnace (1) can be reduced by introducing a gas containing free oxygen (e.g. air) into the entrance section (2) and/or exit section (4) adjacent the roof thereof. Thus a relatively inexpensive gas may often be used in combination with an expensive atmosphere thereby significantly reducing overall process cost. Continuous heat treatment furnaces can readily be converted to perform the method by simply inserting adjacent the roof of the entrance and/or exit section a tube (3) having a slot and/or a plurality of downwardly facing holes (9) and connecting the tube to a supply of the requisite gas. The invention is applicable to both double open ended furnaces and continuous furnaces in which the exit section is filled with a liquid, e.g. oil or molten salt. In these latter cases the gas is introduced in the entrance section (2).