Dec.,
1g12
T H E JOL+Rl-AL OF I-VDliSTRI.4L AaYD Ez17GISEERIL\'G C H E X I S T R Y .
fects of the Orsat apparatus t h a t have been enumerated above, the writer has designed the modification shown in Fig. 5 . 1
r' FIG.
5.
The burette B has a capacity of somewhat more t h a n 100 cc. and is graduated from a point near the bottom upward t o the stopcock J . The stopcock is a three-way stopcock, the position of which is shown b y means of a black glass 4 fused t o its outer surface. The capillary tube connecting J with the pipettes and with the stopcock K has an external diameter of j mm. and an internal diameter of I mm. I n fusing on the branch capillaries t h a t extend downward t o the three pipettes, the internal diameter of the capillary should, a t no point, be much greater t h a n I mm. if the apparatus is properly made. The three absorption pipettes, E , F and G, are of the form already described, and are filled, respectively, with solutions of potassium hydroxide, alkaline pyrogallol, and ammoniacal cuprous chloride. They are connected with the capillary tube from the burette by means of pieces of soft, black rubber tubing of I , j mm. thickness of wall. and these rubber tubes are held in place by x i r e hooks t h a t pass through the blocks behind the joints, and have threaded ends upon which small set screws are placed. This method of attachment renders it easily possible to remove all the glass parts from the frame. Into the open ends of the three level tubes of the pipettes are inserted T h e appnriltus is manufactured b y Greiner and Friedrichs, Stutzerbach i n Thiirinpen, Germany.
901
one-hole rubber stoppers, and through the openings of these stoppers pass the branch tubes from the tube 55,t h a t is 7 mm. external diameter and I mm. thickness of wall. This tube passes downward and is joined by a piece of rubber tubing t o the upper side of the stopcock attached to the cylindrical vessel T , which in turn is connected with V b y the glass tube shown by the dotted line. After the pipettes have been filled with the several reagents, the stoppers connecting the level tubes with the tube SS are inserted in place and the protecting reservoir I'T is. half filled with water. As t h e gas is driven over from the burette into the pipette and is drawn back into the burette, the water in V T rises and falls, but protects the reagents a t all times from contact with the air. The level bottle L is held in place b y a clamp when the apparatus is in transport. After the absorbable gases have been removed from the gas mixture, the combustible residue may be burned, if so desired, by connecting the capillary M , which has a n external diameter of 6 mm. and a bore of I m m . , with a combustion pipette or other suitable device. The case containing the apparatus is 5 7 cm. high, 27 cm. wide and 16 cm. deep. The panels forming the front and back of the case are removed when the apparatus is in use. As illustrative of the speed, accuracy, and uniformity of the results yielded by this apparatus, the following analyses of a mixture of carbon dioxide, oxygen, and carbon monoxide may be cited. A single passage of the gas mixture in one minute into the first absorption pipette serves t o completely remove the carbon dioxide. In the determination of oxygen and carbon monoxide each gas ivas twice passed into the absorption pipette, the first time in tn-o minutes, the second time in one minute. TABLEI V . Carbon dioxide, per cent. .. . . . . Oxygen, per cent . . . . . . . . . . , . . . Carbon monoxide, per c e n t . . . . .
I.
11.
111.
IV.
3.1
3.2
3.1
6 0
3.1 6.0
22.5
22.6
5.9 22.6
5.9 22.7
CORKELLUSIVERSITY, ITHACA, N. Y.
THE STORMER VISCOSIMETER AND THE VALUE O F VISCOSITY DETERMINATIONS BY ITS USE. By GILBERTRIGGA K D J. L. CIRPEUTER.
Received Oct. 9, 1912.
The Stormer viscosimeter is the instrument proposed for use in bringing paints t o a common viscosity, and for the comparison of the viscosities of difierent paints. I t may be briefly described as follows: A weight attached t o a string falls vertically from the instrument. The string pays out over a vertical pulley as the weight falls, and unTvinds from about the shaft of a large toothed wheel, this m-heel lying in a horizontal plane. The large wheel fits into a small Tear on the shaft of the viscosimeter cylinder. When Lne large wheel is caused t o revolve by the falling weight, this shaft is turned, and the cylinder attached t o its lower end is revolved in whatever liauid .
A
902
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
there is in the cup below. A screw gear a t the top of this shaft fits into the teeth of a n indicator wheel, and the whole instrument is so geared t h a t a complete revolution of the indicator wheel represents I O O turns of the cylinder in the cup below. A small water bath surrounds the container cup, and rough temperature control may thus be maintained. The directions for using the instrument are substantially as follows: Take the time for I O O revolutions in water as unity. Then the relative viscosity of another fluid will be the time required for roo revolutions divided by the time for roo revolutions in water. If a liquid is found too viscous for comparison with water, first determine the viscosity of an intermediate liquid, increase the weight and then use the intermediate liquid as standard. After this, calculate back to water as unity. Assuming t h a t in many cases the instrument would be accepted as quite accurate, and t h a t the instructions for its use would be considered complete, an investigation of its merits was determined upon.
Dee., 1 9 1 2
the wheel and “corrected” meaning t h a t the ratio is between the corrected times for each liquid-the corrected time being the observed time minus the Xime for the cylinder to revolve I O O times in air. The following tables and curves show the relative viscosities of several pigments in different quantities of oil, a constant weight on the turning wheel being used throughout. The relative viscosity values are expressed in terms of water as unity, and the ratios of pigment to oil are shown in the top horizontal column.
I n the directions accompanying the instrument, the very important factor of friction in the machine seems to have been overlooked, and this has an important influence upon the values obtained for viscosities. This is especially noteworthy, when i t is necessary to use an intermediate liquid, and therefore increase the falling weight. The following table shows the necessity of determining the friction factor with each change of weight, as well as the necessity for introducing a correction for the instrument’s friction into each relative viscosity value. I n the table, the columns represent the following: ( I ) , the mass in grams of the falling weight; ( z ) , the time in seconds for the viscosimeter cylinder to revalue in volve I O O times in the empty cup below-the air, which represents the retardation of the machine, due to its own friction; (3), time in seconds for cylinder to revolve r o o times in water at 15.5’ C . ; (4),time for IOO revolutions in linseed oil a t 1 5 . 5 ’ C . ; (s), ratio of viscosities of water and oil uncorrected, i. e . , using the values in columns (3) and (4) without regard t o the friction correction in column (2); ( 6 ) , time in seconds for I O O revolutions of cylinder in water after correction for friction, as per column ( 2 ) ; ( 7 ) , time for 100 revolutions in oil corrected for friction in ( 2 ) ; ( 8 ) , corrected relative viscosities of water and oil, i. e . , ratio between values shown in (6) and ( 7 ) . Taking water as unity, columns (5) and (8) show the effect t h a t the friction factor exerts on the relative viscosities of two liquids. Kot to use the friction factor is similar in effect t o a failure to weigh a crucible before a moisture determination. The ratio between the viscosities of two liquids will be referred to hereafter in this paper as “uncorrected” or “corrected, ” depending upon whether the friction value of the machine has been taken into account or not, “uncorrected” meaning t h a t the ratio is between the obscrzvd times for r o o revolutions of
Ratio
of
Piymen f ta
oil. (By
We~yht)
As is clear, upon inspection of the tables, there occur wide variations between the corrected and uncorrected values. And i t follows from this, t h a t any dust o r rust accumulating in any of the bearings or gears of the machine, modifying the friction correction, would change the relative viscosity values ’if the correction were not considered. The above experiments were carried out with a three-fold purpose in view: First, to determine the rate of change of fluidity of the several pigments in oil upon addition of more oil; Second, to determine and compare the relative viscosities of the several pigments in equal quantities of oil; Third, to find out the effect of the friction of the instrument upon the relative viscosities. A series of experiments was next carried through t o determine the effect of changing the mass of the fall-’ ing weight which drives the cylinder in the viscosimeter cup. The instrument was carefully cleaned and oiled, and new friction constants determined with the
TABLEI . (I 1
(21 sx.
.\x-I2 5 1 .00
(>.4 5.0
iJ.84
R.2
(a)
(4)
x’c.
Iiiiii.
I.\.(, I 9.7 6.6
,, 1 A l l l . E 11. -
(5) scr.
Katiii.
14.9 49.7
1:s.s 1 : 5.1 1 : 4.6
30.4
I I X I I ~ I S“:\”
AND
111.
OXlIlE
“B”
AND
Katiu.
miri.sec.
7.2 4.7 3.4
1
1 : 9.s I : 9,s
8.5
44.7 27.2
1 : s
OIL
1 : 4 12.8 27 . 5
1:0 14.4 31 . 2
( 8I
(7 1
bec.
1’. M . 1’.
I
