The Chem
Above. Certain coatings, such as high-gloss synthetic enamels used for refrigerator and original equipment finishes, may be further ground in three-roll tubular mills
Above, Basic resins are ground and mixed with plasticizers, stabilizers, and pigments in a battery of eight 3,000-lb· capacity buhrstone or porcelainlined ball and pebble mills. Left· View of loaded ball an tl pebble mill
In the manufacture of the ΤΡ series of Tygon paints, resins are prepared in chip form on tworoll mills under controlled heat· When cooled they are reground for later mixing and blending
Solvent tanks located at a distance from the main buildings deliver solvent to pressure accumulator tanks which are charged with nonabsorbent nitrogen, eliminating any possibility of solvent satu rated air escaping either into the plant or surrounding atmosphere
Left· View of laboratory showing jar mills. Note spark proof electrical out lets, examples of the safety precautions taken throughout the plant· Even the telephone system is explosion proof 3644
CHEMICAL
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ENGINEERING
NEWS
Ήε«Α4 'Panade
Taking a North gage reading. Normal ball mill grinding will develop North gage readings between 6 and 7· Further grinding in the tubular in ills increase the reading to 8 to 9
Integrated Plastic and Synthetic Coatings Manufacturing Plant Opened rpHE new paint plant of the U. S. Stoneware Co., just com••· pleted at Kavcnna, Ohio, incorporates a number of fea tures believed unique in the manufacture of plastic and syn thetic resin coatings. The range of protective coatings made by U. S. Stoneware requires the processing of such unrelated resins as vinyls, polystyrenes, phenolics, and furanes and the blending of the processed rosin pastes with solvents of differ ent characteristics. While the nature of the various coatings requires different processing procedures, different resins, pig ments, and solvents, it was desirable from a manufacturing standpoint that the basic processing, grinding, mixing, and blending equipment be flexible enough in design, construction, and operation to permit its use with any of the various resins and solvents. The new plant is the culmination of a project started in the fall of 1946. Safety has been a prime considera tion. For example, external piping on all sprinkler lines is loaded with 75 lb. of air instead of water to protect against freezing. If the sprinkler system is set off, air pressure drops permitting water to flow.
Above, The prepared basic materials are loaded into a series of jacketed kettles where they are reduced to normal brushing or spraying viscosity by the addition of solvents or diluents· Temperature control is critical and automatic control is necessary· Kettles are held to correct temperature through automatic controls which feed temperature controlled hot or cold water through the heat exchanger lines
Below, The mixing kettles are emptied through filters into 55-gal· drums for direct shipping or repackaging· Both the ^ jacketed mixing kettles and the ball and pebble mills are so arranged that they may be conven iently loaded from above and emptied from below
Left. Stoneware engineers developed a unique but sim ple method of preventing solvent loss through evapora tion· When the gasketed lid of the mixing kettle is re moved air is drawn in through the lid opening forc ing solvent fumes to rise in a 20-foot-high solvent vent pipe* The rising vapors con dense on the sides of the vent pipe and are returned to the mixing kettles VOLUME
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NO.
4 9 » » DECEMBER
5,
1949
3645
