CHLOROMETHANE from Wichita, Kansas . . . • •
METHYLENE CHLORIDE C A R B O N TETRACHLORIDE • CHLOROFORM USP A N D T E C H N I C A L Ο G R A I N FUMIGANT5
in c a r l o a d , truckl o a d a n d d r u m lott
Frontier offers you swift shipments from > heart of Mid-America . . . high quality from a now plant with advanced processing a n d control equipment. Friendly, personal service, from a firm big enough to deliver the best — and young enough to appreciate your f^business. P l a n t sites available next door 'for overthe-fence" deliveries. W e shall welcome your inquiry. Basic producers of C h l o r o m e t h a n e s , BHC ( 1 4 and 3 0 g a m m a ) . C h l o r i n e , Caustic S o d a , M u r i a t i c Acid, Fine G r a i n S a l t Executive Officer W i c h i t a , Kama»
Plants: W i c h i t a , Kansas Denver C i t y , Texas A
DIVISION
OF UNION CHEMICAL MATERIALS CORP.
&
ADSORBENTS DILUENTS Floridin natural-mineral ad sorbents are successfully being used for applications in ads o r p t i v e refining, filtration, neutralization, decolorization, dehydration, polymerization, catalysis, diluents, insecticide carriers, filters, binders, clean ers, and many others. If your laboratory or pro duction processes can use a n economical, efficient, natural material for these or similar uses* it will pay to investigate. W r i t e today.
FÉAJHPÎN COMPANY/® ADSORBENTS D e p t . B,
70
P . O . Box 9 8 9
C&EN
OCT.
T a l l a h a s s e e , Florida
14,
1957
PRODUCTION
Radomes Look to Ceramics Air Force tries a ceramic m a t e r i a l — a l u m i n a — t o overcome g u i d e d missile temperature troubles C e r a m i c radomes are now leading the assault on a major guided missile problem. T h e problem: High temperatures (far above the range of presently used reinforced plastic) are generated when guided missiles re-enter the atmosphere. U n d e r an Air Force development contract, Gladding, McBean & Co., a West Coast ceramics manufacturer, came up with a solution, has just completed t h e first 10 prototype ceramic radomes. But the going wasn't easy. T h e b i g problem is that a radome must be as transparent as possible to radar waves. This means that a material with the required temperature resistance a n d strength has to have the right electrical properties too. The alumina ceramic was chosen. But manufacturing was a difficult trick since a method h a d to be devised which could h o l d t h e wall thickness to a tolerance of ± 0 . 0 0 1 inch. Gladding, McBean finally worked out a technique to do this. High purity alumina ( 9 7 % A1 2 0 3 ) is mixed with a small amount of organic binder to give it some strength before firing. This slurry is sprayed on a chrome-plated steel mandrel with a spray g u n and the radome is then oven dried while in place on the mandrel. A neoprene bag is used t o cover the whole assembly which is placed in a specially designed pressure vessel. Glycerol is fed to the vessel with a high pressure hydraulic p u m p which raises t h e pressure to about 30,000 p.s.i. T h u s compacted, t h e radome has enough strength to b e stripped from t h e mandrel. It is given a preliminary ( o r bisque) firing at 2200° to 2250°F. a n d then machined on a lathe with a diamond tool to final wall thickness— with allowance for the small amount of shrinkage that will occur in the second firing. A regenerative type kiln is used for the final firing at a temperature above 3000 °F. The prototype radome resulting from t h e process is six inches in diameter and 1 8 inches high. It meets t h e electrical, thermal, and dimensional requirements of the Air Force.-
To make a radome, the spray gun coats a chrome-plated steel mandrel with a slurry m a d e u p of alumina and an organic binder. T h e radome stays on the mandrel while it is oven dried
A neoprene b a g covers the radomemandrel assembly while in a pressure vessel. This step compacts the radome before the first firing in a kiln
PRODUCTION
Drying Gelatine Purity demands for gelatine are most severe in the photographic field, al though pharmaceutical and food indus try needs also call for a high-quality product. American Agricultural Chem ical says it uses a Rodney Hunt evapo rator to get the necessary purity. T h e evaporator removes moisture from r a w gelatine solution at a practical s p e e d without degrading the heat-sensitive protein product, the company says. Basic commercial processes start with pig skins or clean animal bones. Leach ing in aqueous acid releases gelatine. T h e filtered, lime-neutralized solution is then evaporated to dryness. AAC's new method for reducing t h e product to a dry powder a t its Detroit plant involves a three-step process. T h e critical step is the first: Dilute gelatine solution is continuously con centrated by the turbo-film processor at a rate of 2500 pounds (roughly 300 gallons) per hour. The unit removes some 1600 pounds of water in that time, increasing gelatine content from about 20 to 6 0 % . Rotor blades inside the processor dis perse the solution into small droplets which impinge against the heated walls. T h e fluid immediately spirals downward in a thin film. With the liquid in con stant motion, any one particle is ex posed to heat only briefly. "Burn-on" a n d degradation are thus avoided. Next, the hot concentrated solution is chilled quickly in a Votator. T h e highly thickened gelatine paste is then extruded as long "noodles" onto a con veyor belt leading into a surface-com bustion dryer. This third step—the final drying—reduces moisture content down to 6 to 10%. Finally, the finished prod uct is ground, screened, a n d packed by conventional means.
New Color Scale A new color scale for grading petro leum products has been devised by National Bureau of Standards and American Society for Testing Mate rials. Glass standards matching the new scale are now in production. The new scale has 16 uniform stages and covers the range from the black of crude oil through dark red, orange, lemon yellow, a n d pale yellow to crystal clear. ASTM committee on petroleum products has approved the test method.
Resolves and Quantitatively Measures Approximately 9 8 % of the Ρrotein .Content, o f : S a m p i ^
SCHLIEREN INTERFERENCE
(Analytical Model)
This instrument renders,planimetry unnecessary since it indicates on its screen a quantitative analysis of the various proteins contained within the sample tested. The machine employs the Rayleigh system which permits usé of extremely dilute solutions (only j/2 ml. o f undiluted serum is needed for an analysis). Aminco's Electrophoresis includes a built-in refrigeration unit. 5-8510 Clinical Electrophoresis, complete with electrolytic compensator, 'dialysis unit, eyepiece viewer for observing interference patterns, two'film holders for 3 ! /4 χ Ψ/4 in. cut film; package'of'Eastman Kodak contrast panchromatic film, (24 sheets),, interference filter (546 millimicrons),' ; elapsed-time meter, mercury vapor and incandescent light sources :...........;.. $2754 Send for BuIleHn
2287-C~2
AMERICAN If^TRUMll^^OMHC OCT.
14,
1957
C&EN
71
