INDliSTRI.4L A.VD ENGILYEERI-VG CHE-IIISTRY
October 15, 1930
extract into another test tube, leaving the paper strips behind. Some pigments produce colored solutions which interfere with the subsequent color test for magnesium. I n such cases decolorize by adding a few drops of a fresh 2 per cent chloramine T solution a t the boiling point. Avoid a n excess unless the color is very hard to destroy. Disregard the white precipitate which may show up on cooling. Treat the cooled extract with an equal volunie of a 5 per cent caustic soda solution which is clear and free from sediment. Simultaneously run a blank, omitting the test strips. To each add a drop of benzopurpurine 4B dye4reagent for every cubic centimeter of solution. Shake and let stand from 2 to 5 minutes, but do not raise the temperature. A distinct rose-colored precipitate indicates the presence of magnesium. Minute traces of mag4 Benzopurpurine 4 8 can be secured from the Newport Chemical Cornpany. It is dissolved in distilled water using 1 gram of the dye to 4 liters of distilled water.
417
nesium from other sources as well as from the ink itself may show up as a weak red coloration. Application to Dry Pigments
Pigments, as well as inks, can be examined for aluminum and magnesium by converting them into inks and then a p plying the analysis. The pigment is rubbed well with a viscous linseed varnish on a glass slab, and treated with a small amount of cobalt drier. I n this manner fine pigment,s lose their tendency to form colloidal solutions. Literature Cited (1) Eergriwe, Z.anal. Ckem., 76, 354 (1929). (21 Hammett and Sottery, J , A m . C k c n . SOC.,47, 143 (192.5). (3) Winter, Thrun, and Bird, Ibid., 61, 2721 (1929).
Convenient Accessories for Use with the Saybolt Universal Viscometer' Carl Winning STAXDARD OIL DEVELOPMENT COMPANY, ELIZABETH, ii. J.
HE Saybolt Universal viscometer. which is the standard
T
instrument used in the United States for testing lubricating oils and certain other petroleum products, is ordinarily operated in accordance with a n inflexible set of rules. These rules, as well a9 the essential details and dimensions of the apparatus, have been standardized by the American Society for Testing Materials ( 2 ) for the purpose of insuring agreement among the results of various operators, and the lack of flexibility is a necessary feature. The Saybolt Furol v i s c o m e t e r \vas developed and has been similarly standardized to handle highviscosity fuel oils and road oils a t moderately low t e m p e r a t u r e s . Various special viscometers have been used to meet conditions which fall outside the range provided for by the A. S. T. &I. methods. The d e v i c e s described in this paper adapt the Saybolt Universal viscometer, with its ordinary accessory equipment, to two sets of conditions frequently encountered in oiltesting laboratories. Testing of Small Samples
Figure 1-Adaptor to Perm i t Testing Small Quantit i e s of Oil i n t h e Saybolt Universal Viscometer A-1.111 cm.: B--12.50 cm. Dimensions A and B determine the constants of the modified viscometer.
T h e m i n i m u m quantity of oil that can be tested in a Saybolt Universal viscometer is of the order of 80 cc. It is frequently necessary to determine the viscosity of smaller samples and various types of glass and metal micro-viscometers are employed. The Adkins instrument ( 1 ) is typical and has the advantage of being made with 1
Received July 5, 1930.
the same over-all dimensions as the Saybolt tube, which permits interchangeable use in the same bath. The adaptor illustrated in Figure 1 is less expensive than the Adkins micro-viscometer and its use does not necessitate even the labor incident to changing tubes in a bath. (The average petroleum laboratory is not required to test a sufficient number of undersize samples to warrant maintaining a micro-viscometer in a n individual bath with the desirable accessories for stirring and thermostatic control.) The adaptor is a metal plug which can be slipped into a standard Saybolt Universal (or Furol) tube and, when made with the dimensions shown in Figure 1, it reduces the volume of the sample required t o 15 cc. The adaptor must be machined to fit a particular tube. The general operating procedure is the same as for the usual sized sample, the time required for 8 cc. of oil to flow into a suitable receiving graduate being measured. Table I shows the data obtained in calibrating a n adaptor used in the writer's laboratory. From these data it is possible to prepare conversion charts or tables of the particular type vhich may be preferred b y the users of the instrument. It has not been considered necessary to adjust adaptors to any fixed calibration curve, and machining to closer dimensional t o l e r a n c e s t h a n a r e maintained in ordinary shop practice is thus avoided. Each adaptor will, of course, require I C M I.D. i n d i v i d u a l calibration. The a c c u r a c y attainable through m use of the adaptor, although adequate for ordinary requirements, is obvious!y less than that of the standard method, and the use of this device is ~-4.1 A not recommended except for Figure 2-Form a n d Approxim a t e D i m e n s l o n s of 28.6 cc. cases of necessity. Saybolt Viscosity Flask
I- 4.21
AVA LYTICAL EDITION
418
Table I-Calibration of Micro-Viscometer DELIVERY TIME CONVERSION SAMPLE Saybolt Micro FACTOR Seconds Szconds 6.5 6 84 44 5 7.14 13.0 92.8 1.5 6 7.24 112.9 26 3 7.2X 191 5 7.44 51.4 3x3 64.n 7.52 484 7.47 717 96 0 7.57 ion1 132.0
Vol. 2, No. 4
de\-ice used for removing excess oil from the overflow gallery or by any other convenient means. Obtained w i t h a 28.6-cc. Receiving Flask DELIVERY TIME RATIO 60 cc. 28.6 cc. 60 cc./28.6 CC. Seconds Seconds 2354 788 2.98 1846 917 2.99 1139 379 3.00 ioio 337 3.00 864 289 2.99 784 262 3.00 519 173 3.00 383 128 2.99
Table 11-Results SAMPLE
1
2 3 4 5
Testing of High-Viscosity Oils
6 7
The Engler visccmeter, which is of German origin, is frequently used to determine the efflux time of 50 cc. of oil instead of the normal 200 cc. (3, h ) , thereby effecting 5 substantial saving in the time required to test oils of high viscosity. It has seemed desirable to adapt this principle to the Saybolt viscometer, and theoretical calculations, checked u p by experiments. have shown that the time required for the outflow of 28.6 cc. of any given oil is one-third that required for the outflow of 60 cc. of the same oil. Figure 2 shon-s the shape and approximate dimensions of the flasks which have been used. Table I1 shows results obtained with a typical flask in the writer's laboratory. Each figure listed is an average of the results of two or more individual tests. The operating procedure is the same as that involved vhen a 60-cc. flask is used. The oil remaining in the tube after discharging 28.6 cc. can be withdrawn by means of the vacuum
8
The saving of time is obviously advantageous and there is a negligible sacrifice of accuracy. It is believed that this device might well be standardized by the A. S. T. AI. for the testing of lubricating oils having high Saybolt viscosities. Acknowledgment The writer wishes to thank E. M7, Dean, director of tlie Standard Inspection Laboratories, for his criticisms, suggestions, and the interest he showed in this Jvork. Literature Cited :1) Adkin5 and Roger, I K D . EsG. CEEM.,20, 742 (1928). ( 2 ) A S.T. 1 1 . Standdrds 11, I f e t h o d D 88-26, p . 427 (1027). 13) Bleyberg, Pelroleurn, Z.,24, 1416 (19288). (4) Upton, Cornell University Ens. Expt. Sta., Bull. 5 ( 1 9 3 8 ) .
A General Utility Laboratory Still' Gilbert Pitman FRUITPRODUCTS
LABORATORY, UXIVEKSITY
URING the past few years there has been occzsion ' to recover considerable quantities of alcohol, acetone, and petroleum ether in this laboratory. Gradually the still herein described has been assembled until it is now nearly foolproof and continuous operating. The necessary equipment may be found in any laboratory and no special technic is required for its assembly. h 2liter Pyrex short-neck flask is fitted with a 3-holed rubber stopper. Through this are fitted a drain tube from the bottom of the flask to remove residual liquids, a fractionating column, and a tube from the reservoir. By closing the two stopcocks it is possible to obtain a vacuum-tight apparatus for vacuum distillation. A 500-cc. separatory funnel makes a very convenient reservoir. By filling the flask through the reservoir it is not necessnry to remove a single stopper, a feature that will be found convenient during vacuum distillation. This still may be run continuously except for the few moments necessary to remove the residual liquids through the drain tube by suction. Perhaps the feature of greatest convenience is the leveling bottle that prevents the water bath from boiling dry. The outlet tube is set at the level desired in the water bath, and any water lost due to boiling is replaced by the siphon from the leveling bottle. The water in the leveling bottle is supplied froin the drain of the condenser. The flow of water through the system should be so regulated that the outlet tube will be drawing some air from the open end to prevent building u p a back pressure.
D
1
Received June 10, 1930.
OF C h L I f O R S I h ,
BERKELEY,
CALIF.
Once installed, this apparatus will soon pay for itself in time and trouble saved.
1
