Abstract: Chromized nickel- and cobalt-based superalloys have alphachrome phase formed during chromizing, and the amount of that phase is diminished by one or more treatments with alkali-permanganate solution and intervening removal of permanganate reaction product film as by acid dip. A kit of such solutions can be prepared. Low-alloy steel steam boiler tubing can have chromized interior and aluminized exterior, and long lengths chromized without a perfectly sealed retort around it can have end caps fitted with extra pack to reduce oxygen penetration to interior. Chain saw cutter blades can be chromized and carburized. Stripping of aluminized coatings from super-alloys with fluoride-containing nitric acid solution is improved by follow-up treatment with fluoride-free nitric acid solution.

Abstract: A plate tube spacer structure operable for concomitantly effecting both the spacing and the supporting of the individual tubes of a tube bundle, the latter commonly constituting one of the components of a conventionally constructed heat exchanger. The subject plate tube spacer structure includes a plurality of elongated plates that are suitably disposed in stacked, spaced relation so as to allow for a layer of tubes to be interposed between each pair of adjacent plates. The plates each have a multiplicity of tube engaging means formed along each longitudinally extending side edge thereof. The multiplicity of tube engaging means are suitably disposed so as to effectively provide each plate with two parallel rows thereof. The arrangement of the rows of tube engaging means of each plate is such that the multiplicity of tube engaging means of one row thereof are aligned with, but face in a direction opposite to that of the multiplicity of tube engaging means of the other row thereof.

Abstract: An evaporator adapted to convert a liquified gas, such as chlorine, into a gas, the evaporator including an enclosed vapor chamber functioning as a pressure vessel. The vapor chamber is suspended within a water chamber having a heater serving to raise the temperature of the water to a level at which heat transfer through the wall of the vapor chamber causes the liquified gas fed therein through an inlet pipe to evaporate and produce a superheated gas that is discharged through an outlet pipe. The vapor chamber is fabricated of a steel tank whose outer surface is coated with a film of tetrafluoroethylene having a thickness just sufficient to render the film impermeable to water, thereby inhibiting corrosion of the steel surface and the formation of scale thereon, the thickness of the film being insufficient to materially reduce the heat transfer characteristics of the vapor chamber.

Abstract: A method for inhibiting the deposition of porous solid products on the internal surface of fluid conducting tubes in a heat absorbing zone of a steam generating unit by the use of internally plated tubes.

Abstract: An economizer for extracting heat energy from low temperature flue gases while simultaneously removing therefrom contaminates consisting chiefly of oxides and oxygen acids of sulfur. The economizer includes a plurality of heat exchange tube assemblies, each of which comprises concentrically spaced inner and outer tubes of different materials. The spaces between the concentric tubes are filled with graphite which remains in heat conductive contact with the inner and outer tubes while accommodating their differential rates of thermal expansion and contraction upon heating and cooling. In the preferred form of the invention, the outer tube is made of low expansion borosilicate glass, while the inner tube is of copper. The flue gases flow transversely to the tube assemblies while water is rapidly circulated through the copper tubes in order to absorb efficiently the heat conducted sequentially through the glass, graphite and the copper materials.

Abstract: A cross-current pipe heat-exchanger for gases, especially for a gas turbine installation, with at least one collective space for the heat-absorbing gas and a bundle of pipes adjoining a wall of the collective space and formed of a large number of individual pipes fastened in the wall and conductively connected with the collective space; the gas stream which gives off heat thereby flows transversely through the pipe bundle; a number of pipes in the pipe bundle arranged on the inlet side are constructed relatively thick-walled, at least within the area of their fastening in the wall; preferably these thick-walled pipes have a wall thickness of about 50 to 100% of the wall thickness of the wall portion forming the adjacent collective space.

Abstract: A boiler tube and a method for manufacturing the same are disclosed in which an inner surface of the boiler tube used in the center of a high-temperature, high-pressure boiler is formed with a spinel layer consisting of an oxide of iron, chromium and nickel, which is exposed. The specific method of the manufacture is that after the boiler tube is brought into contact with high temperature steam, a magnetic iron (Fe.sub.3 O.sub.4) layer produced on the inner surface is removed.