December, 1933
INDUSTRIAL AND ENGINEERING CHEMISTRY
3. Tanned linoleum which can stand moisture. The solution of this problem, although theoretically possible, probably requires a major step in understanding the nature of binder hydrolysis as well as an effective technic of introducing the tanning agent. 4. Cooperation among linoleum chemists-high board fences are pass& The success of such cooperation in the closely allied rubber industry needs no further comment. Particularly helpful would be a cooperative program on fundamental problems of the industry in some laboratory carrying on closely associated work, as on drying oils.
Among the steps ahead that may be expected in this industry are:
architech-can be approved that it be used as an oitsjhe finish for
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homes. On the other hand, for factory-laid floors in steel house construction, it is especially well adapted. 3. The use of modified linoleum mix in the plastic industry, This plastic, scarcely known outside the linoleum industry. offers possibilities as a remunerative side line to the manufacturer of linoleum. These objectives cannot be obtained in a day or in a year, but the possibilities in fundamental research on the basic problems of the oil-resin plastic should stimulate the industry in further work of this character.
LITERATURE CITED
RECEIVEDJune 16, 1933,
Metals and Condensed Milk Corrosion of Metals in Manufacture of Evaporated and Sweetened Condensed Milk E. C. THOMPSON, R. Y. MEARS,The Borden Milk Products Company, New York, N. Y.,H. E. SEARLE AKD F. L. LAQUE,The International Nickel Company, Inc., New York, N. Y.
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stricted to tests in sweetened 'MEROUS investigators The corrosion of metals in the manufacture of condensed milk. have studied the broad condensed and eaaporaled milk is studied by exs u b j e c t of m i l k and posing metd specimens in equipment in operametals. Some investigators (5, METHOD OF TESTINQ tion. A novel specimen holder is used that 6,8, I S , 15) have studied the infacilitates testing routine. The extent of corroAt the outset, it was decided fluence of metals on milk and to carry out the tests under the have found that milk and milk sion is determined by measuring the weight lost actual conditions e x i s t i n g in products are apt to be affected, by each specimen and by examining it visually. equipment that was in operain one way or another, by certain Corrosion is most active in evaporators, hot metals. Other investigators (3, tion rather than to attempt rewells, drop tanks, and preheaters. The esti4,8,11, 12,14,19) have studied production of these p r a c t i c a l ma fed copper pick-up from typical evaporators the effect of milk on metals and conditions in laboratory exfound that some metjals resist p e r i m e n t s . This course was is 2 . 5 ~p . m . f o r condensed and 1.6 for evaporated attack by milk much better than decided upon as it was direct, milk. At eziery point of test the resistance of others. Still other investigators whereas l a b or a t o r y e x p e r icopper is surpassed by other metals of goodphysi(7,9) have studied related submenting was indirect and incal and fabricating properties. Hard films of jects, such as metals us. cleaning volved the d i f f i c u l t y of conprotective nature f o r m on the metals in certain solutions, sterilizing solutions, trolling aeration, agitation, etc., brine, e t c . A few a u t h o r s which are k n o w n to h a v e a equipment. (10, 17) h a v e d i s c u s s e d t h e pronounced effect on corrosion ( 2 . 11). mechanical and fabricating Drop The testing routine was facilitatLd by the use of specimen erties of materials, whG6 are of great importance in the practical application of materials in dairy work. These holders described by Searle (11). Through the use of these points and the cost must all receive careful consideration in specimen holders, for which parts and specimens were already available, it was possible to carry out a corrosion testing selecting the metal that can be used to best advantage. This paper deals only with the corrosion of metals in the program involving more than nine hundred weight loss manufacture of evaporated and sweetened condensed milk, determinations without expending much more time than was which has not previously been the subject of intensive study. necessary for cleaning and weighing the specimens. A It will be shown that corrosion is more active a t certain points in the process than a t others, and that some met& are less T.4BLE I. APPROXIMATE COMPOSITIONS O F METALSTESTED affected than others. No attempt mill be made t o select the ( I n per cent) best metal as this involves other factors not covered by this METAL Cu Ni Fe Cr Sn Zn Pb Ag Copper 99 9 .. investigation. Nickel 99 5 Tin .. .. . . . . 99.9 . . . . . . The metals and alloys tested are listed in Table I. These Bronze 87 .. .. .. 5 3 5 .. metals are well known to the dairy industry, except perhaps Inconel .. 80 6 13 .. .. .. Monel 29 68 1.5 . . .. .. .. . . the chromium-nickel alloy Inconel, n-hich was mnounced S o f t solder .. . . .. 33 . . 67 .. Silver solder 25 .. . . . . 15 .. 60 recently. I n fact, Inconel was not available commercially 17% Cr-Fe . . 83 17 . . . . .. when the tests -n-ere started; hence the work on it was re18-8 Cr-Ni-Fe .. 8 74 1s . .
11 I h I,
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rid suiiic of it,s p r t s :in: s I i i ) \ w iii I'igiiro I Each specimen was supported on II spiiidlc covered by a Rakelite tube and wzis separnlcd Eroiri other specimens by tul,ular spacers of I3nkclite. Wien siijquirteil in tlie niaiiner sliol~-ii,the speeiiiieiir xere iiisiiintcd Eroiii tlie metal p:irts of the lioiiier arid from I*RCII ot,lier, tlius diriiinnting all c1ct:trolytic effects that r e d t from riictal contacts.
i Y l < k : l ~ i \ ( ;
