Manifold for Disposal of Fumes Given Off during Macro-Kjeldahl Digestive Process EDV,IRD H. TYNER’, .\-orth Dakota State College, Fargo, N . D .
HE disposal of fumes arising during the digestive process in for total presents
Tthemacro-Kjeldahl method
difficulties when facilities for exhaustion of fumes into the air are nonexistent. A manifold that can be operated in an open laboratory, described here, achieves fume disposal through solution in water. The idea of disposing - of the fumes oriRinating during the Kjeldahl digestive process through solution in water is used in the manifdlds designed by Sy (S), kferkle (Z), and Hastings, Fred, and Peterson ( 1 ) for macro-Kjeldahl digestions. This principle is lilielvise employed by almost all semimicro and micro-Kjeldahl procedures xvhere glass manifolds operate in open laboratories. With the exception of the Alerkle (2) manifold, however, which llepends on the pressures developed during digestion t o force the fumes into water, such manifolds usually employ filter pumps or modifications thereof t o draw off the fumes prior to solution.
wooden board covered with sheet lead, to assure rapid drainage of all condensates, rvhich are continuousiy and automatically removed during the digestion process. The manifold rests on the support that tile nipples tip doTvnrvard (end vien- rigure 1). This eliminates virtually all out-of-flask drip. Two glass filter Pumps were connected to the manifold outlets. The Pump attached t o the condensate outlet will, under ordinary Tvater pressures, operate the manifold.
The manifold illustrated in Figure 1 is more rugged and has greater capacity than the glass manifold designed by Sy ( 3 ) . The junction of the Kjeldahl flask lvith the manifold is not tight or rigid as in manifolds previously mentioned (1-3). Merkle (8) objected to the manifold described by Sy (3), because the partial vacuum created by the operation of the filter pump resulted in frothing and an increase in t’ime required for digestion, With the loose-fitting nipple junctions, partial vacuums within the digestion flasks are not produced. 50 frothing or tendency of spatterings to collect in the neck of the digestion flask or increase in time required for ’ complete digestion has ever been observed with soils or plant materials. Soils and other materials R-hich contain large amounts of inert solids usually bump s t r o n g l y d u r i n g the latter stages of the digestive process. It is conceivable, that rigid manifold-Kjeldahl flask junctions might loosen and permit sulfur dioxide fumes t o escape into t’he open l a b o r a t o r y . Flask motioninduced by bumping does not interfere with the operation of the manifold described. The strong inward flow of air around the nipples in the neck of the flask prevents the escape of sulfur dioxide Figure 1. Diagram of bIanifoId fumes into the open laboratory. Moreover, the loosefitting nipple junction faciliFour-inch lead pipe was used for the main portion of the nianitat,es turning the flasks during the initial stages of digestion and fold illustrated in Figure 1. This was hammered into a rectheir removal Tvithout the necessity of handling acid-covered tangular shape (see end view Figure 1) to facilitate subsequent Stoppers, where rigid junctions are employed. casting operations. A cloth m-as tied over one end of the pipe, This manifold has been in use since 1937. The only mainafter which the pipe was packed with clean dry sand. Twelve nipples were cast a t approximately 11.5-cm. (4.5-inch) intervals tenance required during this period has been occasional replaceon the flat portion of the pipe by pouring molten lead into inment o f t h e rubber connections. verted 25-ml. Caldwell crucibles. .4 casting technique that reLITERATURE CITED sulted in perfect casts a t all times consisted in centering the crucible a t the desired spot on the manifold and sticking it in (1) Hastings, E. G., Fred, E. B., and Peterson, W. H., Ind. Eng. nletal rim (9 cm. in place with a ball of plastic clap. il Chem., 19, 397 (1927). diameter) was then set over the crucible and pushed into the ( 2 ) klerkle, F. G., 16id.,8,521 (1916). clay matrix surrounding the crucible. Dry sand Jvas poured into (3) sy, A. p,, Ibid., 4, 680 (1912). the metal rim surrounding the crucible almost to the top of the RECEIVED September 14, 1945. Contribution f r o m the Soils Division. crucible. The metal rim and sand Tvere merely safety measures Published with the approval of the Director of Xorth Dakota Agricultural t o prevent damage t o the manifold by spattering of molten lead. Experiment Station. Clean molten lead was then poured into the crucibles. After it had solidified, more lead was added if necessary to take care o f any shrinkage a t the top of the cast. After the casts had cooled, the crucibles, etc., vere removed. An approximately 9-mm. (0.375-inch) hole Tvas drilled through the center of each The seventh congress on spectrography, under the auspices of the nipple, the cloth removed, the sand emptied out, and a condenGroupement pour l’dvancement des MBthodes d’Analyse Spectrosate well hammered out (end vimv Figure l), and lead end plates and two approximately 6-mm. (0.25-inch) lead tubing outlets graphique des Produits MBtallurgiques, was held January 21 t o 23, were welded onto the manifold with a ion- acetylene flame. 1947, at the Laboratoire Central de l’Armement, 1 Place SaintIn setting up the manifold for operation a slight tilt away from Thomas d’dquin, paris, -prance. ~h~ report of the congress, in a :he pumps was given the manifold support, which consisted of a 280-page paper-bound book, is divided into three an account Of the meetings, the technical papers, and illustrations. i Present address, Agricultural Experiment Station, Morgantown, W7.Va.
Seventh Congress on Spectrography
273
