Abstract: A process for absorbing SO.sub.2 from a gas in a packed column employs a low aqueous sulfite feed rate of 0.05 to 1 gallon per minute per square foot of tower cross section, or preferably 0.1 to 0.3 gallons per minute per square foot. Lower capital costs and lower operating costs result because of less tower equipment, lower pressure drop, reduced oxidation to sulfate, and elimination of pump around as compared to the conventional processes. Also disclosed is an improved liquid distributor.

Abstract: A siphon tube assembly for papermaking dryer drums having a threaded rotary elbow connection between support and siphon tubes permitting the tubes to be selectively oriented by rotation of the elbow connection between an installation position wherein the tubes are in general alignment and an operative position wherein the tubes are angularly related. In a preferred embodiment, the siphon tube is braced in rigid engagement with the interior of the dryer drum for use as a rotating siphon, it being also contemplated that the present elbow joint may be embodied in stationary siphons. The elbow joint provides an operating keyway accessible through the interior of the support tube for manipulating rotation of the elbow joint without requiring the use of handholes or manholes in the dryer durm.

Abstract: A superheater tube shield of refractory material comprises a pair of elongated half shields of identical interchangeable interlocking size and shape, each half shield having a semi-circular sidewall portion extending between and to diametrically opposite tongue and groove side wall portions which are assembled together about the tubes by axially inserting elongaged tongues into the elongated grooves. Refractory cement may be applied to attach the half sheilds to the tubes.

Abstract: A grinding wheel is described which is bonded with a phenol formaldehyde resin based bond containing hexamethylenetetramine as the curing agent. The wheels are made by first wetting the abrasive with furfural in varying quantities relative to the amount of hexamethylenetetramine in the phenol formaldehyde resin. Different amounts of the curing agent require different specific amounts of furfural to produce optimum properties in the finished grinding wheel.

Abstract: A cyclic screening apparatus (10) and method utilizes multiple air flows and differential air pressures to separate undersize and oversize particles from a mixture of 5 to 50 micron size particles. The apparatus (10) comprises a support (12) including a first conduit (14) connected to a blower (16). A lower undersize particle collecting housing (20) has a secondary air inlet (24) and outlet (26) connected to a suction fan (SF). A screen is clamped between the lower housing and an axially movable and pivotable upper receiving housing. An air distributor rotor (R) is slowly rotated below and directs the first air flow through the screen and into the upper chamber and through a lower portion (40) and against the bottom of lower housing. A rotary nozzle (80), with the help of incoming secondary air flow, disperses particulate material onto the screen below.

Abstract: This invention provides thin, flat, water-impervious polycrystalline ceramic bodies composed of at least 99.5% by weight alumina, predominantly in the alpha crystal form. These bodies have a density of at least 3.9 Mg/m.sup.3, an average surface roughness of 44 nm or less, typically 40 nm or less. The properties of the finished ceramic bodies make them ideal substrates for highly reliable electronic components, especially for high temperature environments. Processes for obtaining such bodies by direct firing of slip cast tapes are also described.

Abstract: An efficient low pressure drop packing element for exchange columns is made up of a plurality of preformed vertical sheets, each having a plurality of inclined rows of adjacent relatively short inclined troughs including valleys and ridges extending between upper inlet edges and lower outlet drip edges and projecting alternately outwardly from one side and then the opposite side of the median plane of each sheet. The sheets are arranged so that the inclined rows of the troughs in adjacent sheets are oppositely inclined and in criss-crossing relation to the inclined rows of the adjacent sheet of the packing element causing frequent changes in direction of liquid flow and whereby the both sides of each sheet are more easily and uniformly wetted by the frequently diverted liquid flowing downwardly over the surface thereof.

Abstract: An improved resin bonded grinding wheel composition is shown making use of a kyanite or sillimanite or andalusite filler or mixtures thereof. More particularly the grinding wheel is a hot pressed phenol formaldehyde wheel having an alumina-zirconia abrasive with a kyanite additive therein. These wheels can be used for heavy duty metal grinding and have been determined to be especially useful for the snag grinding of titanium metal.

Abstract: Fine alumina powders for making alumina bodies are produced by seeding of a non-alpha alumina with submicron alpha alumina particles, firing, and crushing and milling the fired product to a fine powder. The powder so produced may be formed by conventional techniques such as pressing, granulating, slip casting, tape casting, and extrusion, and sintered to produce the desired fired product.

Abstract: A coated abrasive which is advantageous for certain applications has at least two distinct layers of abrasive grits: a coarse outer layer and a finer inner layer. The median particle size of the grits in the outer layer is at least 150% of that of the inner layer grits. The grits may be adhered to the backing with adhesives compounded primarily of acrylates and cured by exposure to UV light. A product made in this way is effective for one step fining of plastic ophthalmic lenses.

Abstract: Previous coated abrasives with adhesives suited to rapid, UV light initiated cure often had intractable curl problems. Therefore, such coated abrasives have been unsuited to precision finishing of workpieces with strict flatness or other curvature requirements, such as read-write heads for magnetic recorders or computer memories.This invention provides coated abrasives, having adhesives with cure initiated by UV light, which are suited to curvature control by the methods used conventionally for magnetic recording media. The preferred adhesive formulations include reaction products of 2-hydroxyethyl acrylate with polyol polyester oligomers capped with isocyanate end groups, alkoxylated diacrylated monomers, and N-vinyl pyrrolidone and other monomers with only one polymerizable unsaturated double bond per molecule, and sometimes also include nonpolymerizable thermoplastic polymers.

Abstract: Aluminous proppant media in the form of sintered bauxite spheres containing silica are improved in resistance to stress corrosion by inclusion of zirconia in the mix prior to firing in the amount of a silica to zirconia ratio of from 6/1 to 20/1.

Abstract: A method for making grinding wheels having an annular grinding section mounted on a central hub in which a slurry of abrasive particles and ceramic bond is coated on a pre-formed core, shaped, and fired. Method has particular advantage in formation of wide wheels and contoured wheels. Premium abrasive may be employed in the wheels.

Abstract: A coated abrasive surface polishing product with excellent finish refinement capability and long life can be made by coating a layer of resilient material laminated to a conventional coated abrasive backing with an elastomeric maker adhesive and conventional abrasive grain. Optionally, an intermediate elastomeric adhesive layer may be used between the resilient layer and the maker. The best resilient layer is a reticulated open cell foam with a 50% compression force of less than 90 kilopascals, and the best elastomers, for both maker and any intermediate coating used, have after cure a tensile strength between 30 and 52 megapascals, a 100% modulus between 2.4 and 16 megapascals, and an ultimate elongation to break between 375% and 750%. For long useful life, the product preferably should have a phenolic resin sizing adhesive over the abrasive grain.

Abstract: The hardness and microstructure of aluminous abrasives produced from alumina gels are enhanced by introduction of seed material as by wet vibratory milling of the material with alumina media, or by the direct addition of very fine alpha alumina particles in the amount of 1% or less.

Abstract: A device for use in underground drilling comprising:a tubular housing,a down-hole motor mounted within the housing and having an output shaft,means for connecting said output shaft to a drill bit,means for connecting said housing to a drill string,first and second stabilizers mounted on said housing,said first stabilizer being mounted nearer than the second stabilizer to the output shaft connecting means,at least one of said stabilizers being an eccentric stabilizer, andat least one stress relieving means between the first stabilizer and the means for connecting the housing to the drill string.

Abstract: This invention relates to organically bonded abrasive articles that include grinding aids. It has been determined that when known grinding aids such as alkali metal sulphates and alkali metal chlorides are cofused in about eutectic proportions and added to thermoset resin bonded abrasive articles in the form of finely crushed particles having an approximate eutectic composition that an improved abrasive article results.

Abstract: Sub-micron sized powders of the ceramic metal oxides such as zirconia, alumina, titania, etc. are produced by precipitation upon mixing aqueous or aqueous/organic solutions of salts of the corresponding metal(s) with substantially 95% solutions of ammonia donors such as hexamethylenetetramine which are capable of reacting with water to give ammonia. The precipitates are treated with an alkali metal hydroxide to remove adsorbed organic matter, neutralized after completion of this treatment with acid, then washed with ammoniated water to remove any residual soluble salt and/or organic matter, dried, and calcined. The powders thus produced are readily sintered to high density ceramic bodies after conventional pressing or casting into a desired shape.The process is especially suited to the production of zirconia powders, either pure or doped with conventional stabilizing oxides such as yttria, magnesia, or lime.

Abstract: Inexpensive hydrates of alumina are used for the production of dense, submicron alumina bodies by conversion of the alumina hydrates to a soluble form which is then used to produce a boehmite gel. The boehmite gel, with very small particles of alpha alumina intimately dispersed therein is dried and fired to 1300.degree. C. to 1450.degree. C.