Sintered Pyrex Glass Aeration Tubes R.D. COOL^ AND J. D. GRAHAM,Laboratory of
Pharmacology, University of Pennsylvania, Philadelphia, Pa.
H E applications of sin- packed by tapping the mold. The mold and glass were placed an electric muffle furnace maintained at white heat (l20Ooto tered Jena glass d i s k s in 1400' C.) for 30 to 40 seconds, until a distinct red color had have become well k n o w n crept completely over the outside of the mold cup, C. The through their wide use in fil- mold was then removed from the furnace and the inner carbon tration and in gas a b s o r p - plug, P, withdrawn. By this initial heating the glass had sintered just enough so that the plug could be removed without tion apparatus (3). Recogni- destroying the form of the glass thimble. If the sintering was tion of the desirability of con- completed without removing the inner plug, so much shrinking structing similar devices from of the glass took place that it was practically impossible to Pyrex brand glass has re- remove it. As soon as plug P had been removed, the outer cup, C, of the mold and the powdered glass, G, were replaced in the sulted in several articles (1, furnace until the color of the mold just approached that of the 2) dealing with this subject. oven. This usually required an additional 30 seconds. The In some cases shapes other mold and sintered glass thimble were then removed from the thanthewell-knowndisk seem furnace. On cooling, enou h shrinkage of the glass had occurred so that it readily dropped from the inverted mold. desirable. F o r d i s p e r s i n g gases into fine bubbles in Because the mold, glass, and oven undergo unequal cooling liquids, for ready saturation effects during various parts of the procedure, more uniform of the liquids, or for rapid and results could be obtained by using the appearance of the mold FIGURE 3.. SECTION THROUGH quantitative a b s o r p t i o n of and of the glass rather than a definite period of heating as MOLDFOR SINTERING Pow- constituents of the gases, the the criterion for completion of the sintering. The whole DERED GLASS thimble-shaped alundum gas sintering process, including packing of the mold and removal C Cup bored from 15-mm. graphabsorption s p r e a d e r s h a v e of the finished thimble, requires about 5 minutes, and by using ite god; G, powdered Pyrex glass; P,plug made from 6-mm. arc lamp proved very effective when several molds, so that no waiting is required for cooling, a oarbon. atmlicable. In the course of number of thimbles can be made in a reasonably short time. If the thimble is wrapped to within 3 mm. of the open end work in this laboratory it becaze desirable to devise an apparatus for the quantitative absorption in strong alkali of with asbestos paper tape, it can be sealed to Pyrex glass a vapor mixed with steam, and the authors succeeded in pre- tubing in the usual manner. paring a highly satisfactory gas disperser from Pyrex brand LITHRATURE CITED glass which, under such conditions, seemed to offer marked (1) Bruce, W. F., and Bent, H. E., J. Am. Chem. Soc., 53, 990 (1931). advantages over one made from alundum. (2) Kirk, P. L., Craig, R., and Rosenfels, R. S., IND.ENG.CHBM., Pyrex glass tubing was crushed in a porcelain mortar and Anal. Ed., 6, 154 (1934). separated into portions by screening. Powdered glass of the (3) Prausnitz, P. H., Ibid., 4, 430 (1932); Bee bibliography of thia paper and Ibid., 6, 291 (1934) for references to patents coverdesired size (80 to 100 mesh was used in the particular case mentioned) was placed in a mold of graphite (Figure 1) and ing fritted glass filters.
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REICEIVBID July 20, 1934.
Present address, University of Akron, Akron, Ohio.
Gas-Absorption Bulb for Use with Small Amounts of Reagent
TOP MAY SE OPEN AN FLARED TOR WBBF STOPPER OR G W h U WAS STOPPER
J. A. SHAW The Koppers Research Corporation, Pittsburgh, Pa.
R
ECENTLY the writer had occasion to make a quantitative study of the oxidation of minute amounts of nitric oxide in coke-oven gas and gum formation resulting therefrom. The investigation included a critical examination of the analytical method described by Schuftan.1 Testing such a method naturally involved making synthetic samples by adding small amounts of nitric oxide (< 1 p. p. m.) to cokeoven gas free from nitric oxide. As in all ultrasensitive work, it was desirable to use as little reagent as possible. It was also necessary to keep backpressure in the system to a minimum, and to accomplish this under conditions requiring unusually thorough scrubbing combined with considerable capacity. Since no absorber on the market would fulfil all these demands, a special bulb (shown in the illustration) was designed. (The glass-blowing required in developing this absorber was done by F. PierceNoble, 110 Benham Ave., New Haven, Conn.) 1
Sohuftan, Paul, Brennslof-Chem., 13, 104-8 (1932).
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