1058
THE JO UENAI, OF I N D USTRIAL A N D ENGlNEERi NG CHEMISTR Y
VOl. 13. No. 11
Flask Calibrating and Marking Device’ By Guilford L. Spencer THECUBAN-AMERICAN SUGAR Co., TINGUARO, CUBA
This device was originally intended only for marking precision flasks. It may be used, however, in combination with a calibrating buret in judging the accuracy of the marking of such flasks. It locates the position of the meniscus with greater accuracy than is possible by the eye, with customary aids. As is evident in the drawing, the device is a means of bringing a pair of electrodes into contact with acidulated water a t the center of the meniscus, in the neck of the flask, indicating the point of contact, and marking the neck with a ring a t this level. The electrodes are connected in series with an incandescent lamp and the service wires. If desired, a cell containing dilute sulfuric acid, into which dip platinum wires, also in series with the lamp, may be used in addition to the signal (described later) for indicating the contact of the electrodes with the liquid in the flask. A galvanometer could be used for this purpose, but these devices have not been found necessary. The audible and visual signals of the contact of the electrodes a t the meniscus me clear and within the accuracy of the calibrating buret and the practical applications of the flasks. The liquid used in calibrating is distilled water, containing about 1 cc. of sulfuric acid per liter. The usual precautionrJ of expelling the air from the dilute acid and rtvoiding vibration and temperature fluctuations are observed. The neck of the flask is varnished or waxed in a wide hand a t the probable location of the mark: the flask is clamped in its holder; the desired volume of acidulated water is measured into it with the calibrating buret. The holder is next slipped over the micrometer post, with the guide pin in the groove, and the flask is raised nearly to contact of the electrodes with the liquid; and the holder is clamped to the post and is centered by means of the three screws. Previous to placing a flask in the apparatus, the graving needle is so adjusted that its point falls a t the bottom of the central electrode and it is then withdrawn. A lock nut is provided for making this adjustment, which is semi-permanent . Having centered the flask, the switch is closed, and the micrometer head is tnrned little by little, lifting the flask until the central electrode, which is slightly higher than the other, touches the liquid. At the instant of contact, there is a distinct sound made by the evolution of gases, and this or the appearance of gas shows that the contact has been made. The wattage of the incandescent lamp determines the distinctness of the signal. The switch is now opened. Experience has shown that with rapid work, and before the gas and heat evolved appreciably affect the liquid, three or four contact points can be located within the limits of accuracy of the calibrating buret, and guided by the noise only, or in other words, with the operator blindfolded. The graver is now pushed till nearly in contlact with the neck of the flask and then, by means of the fine adjusting screw, to full contact. A spring and follower press against the graving needle. The spring and follower in the graver-holder, bearing on the graver, provide against the effects of slight distortion of the neck, or failure to exactly center the flask. The sweep is revolved and the graver cuts a ring in the varnish or wax, and the glass is ready for etching. v
The micrometer may be made with standard taps and dies
(S. A. E.) 24 threads per in. This corresponds nearly to 1.058 mm. pitch or vertical travel of the post per complete revolution of the head. Since the micrometer head is sensitive to less than one-twentieth revolution, the instrument is sensitive to less than 0.0529 mm. vertical travel of the post. Assuming the marking of a Rates’ 100-cc. flask of 12 mm. internal neck diameter: Area = 113.1 sq. mm. and 113.1 X 0.0529 = 5.98 cu. mm. or 0.006 cc. It is possible to graduate a liter flask of 20 inm. internal neck diameter to 0 . 0 2 cc. This is well within the limits of the accuracy of the calibrating buret. A smaller post having 28 threads per in. (5. A. E.) or‘,a metric post could be used if desired.
E 4
tW.Z
Support
n,n, A-Flask-clamp B-Micrometer head and post C-Flask centering-screws D-Platinum electrodes E-Sweep
F-Graving tool G-Lower end of micrometer post H-Adjustable plate for hand rest I-Switch
A pointed screw was used, in graving, in the original model of the instrument. It was noted in marking single-graduation flasks that the errors fell on either side of the correct number, but in two graduation flasks, the errors of the upper marking usually fell on one side. This was possibly due to a difference of neck diameter and a slight eccentricity of the point. The sliding graver was devised to assure 8 correct average. The flasks Iisted below were graduated with the original model, using the screw-graver and a centering flask-clamp. The first two lots of flasks were checked against “doublechecked” weights on a chainomatic balance and the others 1 Presented before the Section of Sugar Chemistry and Technology a t t h e 61st Meeting of the American Chemical Society, Rochester, N. Y., against calibrating burets, certified by the Bureau of StandApril 26 to 29, 1021. ards :
THE JOURNAL OF INDUXTRIAL A N D ENGINEERING CHEMISTRY
Nov., 1921 50/55 Cc. 60.014 0.014 54.981 0.019
50/55 Cc. 49.993 0.007 54.979 0.021
50.019 0.019 54.972 0.028
49.974 0.026 54.969 0.031
60.029 0.029 54.980 0.020
50.016 0.016 54.967 0.033
100 c-c .~ . _..
99.776 99.987 100.026 99.990 100.012 100.004
0.024 0.013 0.026 0.010 0.012 0.004
The above 100-cc. flasks were chosen a t random from forty-eight consecutively graduated, and checked against weights. One out of every six of the remaining flasks was tested against the calibrating buret. The extreme range was FLASKS CHECKED WHEN 60/55Cc. 50.00 54.99
50/55 Cc. 50.01 55.00
50.02 55.00
49.99 64.99
60.00 55.00
49 * 99 55.00
so.02 54.99
49.99 54.99
50.00 55.00
50.00 55.02
50.00 55.00
50.00 55.01
50.00 55.00
50.01 54.99
100 cc. 100.01 100.00 99.98 100.00 99.99 Q9.99 99.97 100.01 100.00 100.01 99.98 99.99 99.99 100.00 99.99 100.02 100.00 99.99
~SSUED
300 Cc. 299.98 300.02 300.00 300.02 299.99 300.02 299.98 299.97 300.02 299.97 299.99 300.01 300.02
500 Cc.1 499.97 499.95
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99.98 to 100.02 cc. Many of these flasks have been rechecked when issued to the factory laboratories and appear in the foregoing lists. A similar method of marking has been considered by the author but has not been tried out. I n this a very fine capillary tube of glass replaces the electrodes and tinted water the diluted acid. At the instant of contact of the capillary tube and the water, the latter shows clearly in the tube. The author found a description of this method of measurement in an old edition of Mohr’s “Titrirmethode,” after he had used it several years.’ This method of measurement may be applied in determining the specific gravity of viscous material that cannot be tested with the customary appliances, using instead a tube or cylinder. For example, molasses, freed of air by suction, is weighed in a tube of 15mm. internal diameter that has been calibrated with a modification of the marking device. Water is measured upon the molasses from a closely divided buret until contact with the electrode is made. The calculations are obvious. The accuracy of measurement in this case in so far as regards the electrode device, is approximately 0.01 cc. The electrode would be in fixed position. This method could be used with larger vessels, e. g., of 50 mm. diameter, with accuracy of the third decimal place. The work of marking and caIibrating the flasks listed in this paper is by Mr. Joseph B. Harris, Control Chemist and Assistant Superintendent, Cardenas (Cuba) Refinery.
ADDRESSES AND CONTRIBUTED ARTICLES The Forests of the United States as a Source of Liquid Fuel Supplyz By Ralph C. Hawley YALEUNIVERSITY, NEW HAVEN,CONNECTICUT
The purpose of this paper is to present a concise statement showing the amount of wood available for conversion into liquid fuel which can be produced annually on the forest lands of the United States (Alaska and insular possessions excluded). The forested area of the United States is as follows: TABLE1.-AREA A N D GROWTHOF AREA FORESTED Acres
CHARACTER
245,000,000 Second growth forests 81,000,000 Waste !and on which nothing is growing or likely to grow without reforestation 137,000,000 Virgin forests
463,000,000
FORESTS OF THE UNITED STATES1 PRESENT GROWTH POSSIBLE GROWTH Cu. Ft. Cu. Ft.
THE
5,995,000,000
14,700,000,000
Nothing Nothing
4,860,000,000 8~2203000,000 27,780,000,000
5,995,000,000
1 All
figures in this table are taken from “Timber Depletion,,,Lumber Prices Lumber Exports and Coocentration of Timber Ownership Report on Sehate Resolution 811 by The Forest Service, U. S. Depaitment of Agriculture.
To-day the annual growth of wood is approximately six billion cubic feet. The possible growth, provided the lands are properly restocked after cutting, and protected, is conservatively estimated at twenty-seven and three-quarters billion cubic feet per year. Not all of this annual growth would be availablefor manufacture into liquid fuel. Lumber and numerous other forest products must be provided for. Each year approximately twenty-six billion cubic feet of wood (far in excess of the present growth and taken principally from the accumulation of virgin timber) are removed from the forests, distributed as shown in Table 11. 1 Five measurements with 100-cc. calibrating buret in calibrating and in checking. 2 Presented before the Section of Cellulose Chemistry a t the 6 l s t Meeting of the American Chemical Society, Rochester, N. y.,April 26 to 29, 1921.
TABLE 11-AMOUNT OF
W O O D REMOVED ANNUALLY FROM THE THE UNITEDSTATE@
CUT Lumber Fuelwood. Other products.. Destroyed by fire, insects and fungi..
FORESTS OF
Equivalent in Standing Timber, Cu. Ft.
................................ ............................. ........................ ....... TOTAG ...........................
8,913,300,000 10,450,000,000 4,955,615,000 1,730,000,000 26,048,915,000
1 All f i g u r e s 5 this table are taken from “Timber Depletion,,,Lumber Prices, Lumber Exports and Concentration of Timber Ownership Report on Senate Resolution 311 by The Forest Service, U. S. Depaitment of Agriculture.
Out of this total cut, at least 4,800,000,000 cubic feet cut for lumber are lost through waste in the woods and a t the mills. Adding to this the 1,730,000,000 cubic feet destroyed by fire, insects, andifungi gives a total of 6,530,000,000 cubic feet of wood annually wasted which should be available for liquid fuel, without encroaching upon the supply needed for other purposes, Furthermore, the possible annual growth (27,750,000,000 cubic feet) exceeds the annual requirements (26,000,000,000 cubic feet) by 1,750,000,000cubic feet, furnishing an additional 1,750,000,000 cubic feet for liquid fuel. TABLE 111-ESTIMATEOF AMOUNTOF WOOD FOR LIQUID FUELWHICH COULDBE SECUREDFROM FORESTS OF THE UNITED STATES WITHOUT ENCROACHMENT UPON SUPPLY OF OTHERFOREST PRODUCTS Cu Ft - .. Waste in the woods and a t the mills ~,800,000,000 Losses from fire, insects and fungi (taken out in thinnings) 1,730,000,000 Excess Of possible growth over annual cut (taken out in thinnings) 1,750,000,000 Increased growth due to more intensive croD management (taken out in thinnings) 2,750.000.000
..........................
TOTAL.....
11,030,000,000
Finally, the increased growth which will follow intensive forest crop management, particularly the removal of small wood in 1Spencer,
“Handbook for Chemists of Beetaugar Houses,” 1897.
.
