Industrial Radioactivity Uses Suggested Λ STAFF REPORT

IJETTER control through ins t ruments was the observed theme of the Second Instru­ment Conference and Exhibition of the Ins t rument Society of America held in Chicago last month. Ins t rumenta l control for processes, plants, quali ty, and concen­tration was considered as were new in­s t ruments and methods.

One of the sessions a t t ract ing part icular a t tent ion was tha t on the industrial use and measurement of radioactive materials. Following a review of the fundamentals of radioactivity by C. J. Overbeck of Nor th­western University which prepared the audience for the following discussions, R. D. Evans of the Massachusetts In­s t i tu te of Technology spoke on the appli­cation of radioactive indicators to indus­trial, problems. This field is now suffering from a lack of publication, according to Dr. Evans, who indicated that , while there are some 2,000 papers published on the use of radioactive materials in medi­cine, there are only about a dozen dealing with industrial applications. He indi­cated that , with the increased availability of isotopes from the United States atomic energy piles, there should be an increase in published information in this field. Dr . Evans dealt mostly with possibilities for industrial application and examples of some in current use in process control, process mechanisms, product marking and identification, and industrial hygiene.

As an outstanding example of process control, Dr. Evans described the use of radiosodium oleate in the coating of rayon fibers. These fibers of about 0.004-inch diameter must be coated with a continuous and uniform sodium oleate and oil finish in which the amount of oleate is quite small, constituting about 10% of the weight of the fiber. Nonuniform coating gives non­uniform dyeing and snarling in the knit­ting process. By the use of a small amoun t of radiosodium in the oleate, it is possible to check the coating process with such sensitivity tha t the distribution can be determined within 2 % of a 1-mm. length of fiber.

There are a great many possibilities for use in industrial marking, according to Dr. ftvans, and it is a straight-forward and safe process whereby tools and equipment , products, and many other units or com­modities may be marked so tha t they may be traced easily. Almost any material, he vsaid, has some radioactivity of the radium or uranium type of a very low order. By a slight increase with a quali ty of radiat ion which is easily distinguished, a level can be reached which is harmless but useful. Dr . Evans est imated t ha t the cost of such industrial marking would vary considerably but should be in the range of one cent to one dollar per ton.

Another use cited by Dr . Evans offered a simplification of the problems of mixing. As an example, he cited the use of radio-phosphorus in laboratory scale electric steel furnaces for determining the rate of approach to equilibrium under various changes of temperature and other con­ditions. Very small amounts are required in such operations, he said, and at such low concentrations are quite harmless. This principle can be applied to almost any mixing problem, he declared. In indus­trial hygiene, the uses were many, he indi­cated, and mentioned such applications as the incorporation of traces of radioactive isotopes with poisonous materials, such as mercury compounds, for purposes of s tudying their entrance into the bodies of persons handling them.

Two part icularly interesting measuring "devices were mentioned by Dr. Evans . One of these was an area measuring device which utilizes a metal plate uniformly coated with polonium. The other was a thickness measuring instrument called a penta t ron by which such measurements as the thickness of a steel pipe can be determined externally.

Process Control The application of ins t rument control

systems to the sea water bromine process was discussed by Porter H a r t of the Dow Chemical Co. This process, he s ta ted, consists essentially of acidifying sea wrater and oxidizing with chlorine to liberate free bromine which is blown out of solution with air, mixed with sulfur dioxide, and passed through absorbing towers with water, forming hydrobromic acid and sul­furic acid solutions. The hydrobromic acid solution is then chlorinated to free the bro­mine which is driven off with steam and collected in liquid form. Mr. Har t said tha t all recording ins t ruments used in the pTT, oxidation potentials, gas analysis, sea

Nearly 7,000 attended the ex 139 exhibitors displayed $0

water salinity, and tempera ture are self-balancing potentiometers of the galvanom­eter type; controllers are recording with pneumat ic control S3'stems and operating control valves a re equipped witri position­ers. With this equipment, he said, the production of liquid bromine from raw sea water is completely automatically con­trolled except for manual operations con­sisting of adjusting pumping rates, for­warding l iquors , unloading raw materials, and similar operations.

Polarographic analysis a n d its principles, techniques, a n d applications were dis­cussed by L. ID. Wilson, Corn. Products Refining Co., and "Adapta t ion of the Automatic Spectrophotometer f or Spe-eial Measurements ' ' was the t i t le of a paper by II. H . Kienle a n d K. I. Stears, American Cyanamid Co.

A new metals comparator which fur­nishes a convenient and nondestructive rapid method of determining w h e t h e r or not a part icular piece of metal i s identical with a s t anda rd specimen i n composition and characteristics was described by E>. E. Bove}', General Electric Co. This unit operates t h rough insertion of the test piece in t h e center of a solenoid forming o n e leg of a balanced circuit , the other l eg of vvfcûch is a variable resistance. I n comparison with a s t anda rd specimen, a var ia t ion in impedance of t h e tes t coil a n d resultant un­balance of the circuit are indicated o n a microammeter.

I n discussing an electronic dew-point indi­cator, Vernor Suomi, Universi ty of Chi­cago, s tated t h a t t h e dewpoint method of moisture measurement is shown, to harve a definite advan tage over o the r common methods i n t h a t its percentage accu racy is nearly cons tant over a wide range of tem­peratures- D r . Suomi described an elec­tronic dewpoint hydrometer \rfciicli main­tains a small metal-mirror a t tlie dewpoint temperature b y means of photoelectric ob­servations and radio-frequency induction heating.

I n the election of officers, Paul G. Exline, Gulf Research Corp. , w a s elected to t h e presidency of the ISA.

hi bit uf instruments at which million worth of equipment

8980 C H E M I C A L A N D E N G I N E E R I N G N E ^ S