Glass Pressure Vessel with Heatihg Jacket. John H. Pomeroy, Division of Biological and Medical Research, Argonne National Laboratory, Chicago, 111. GLASS
and stainless steel pressure vessel for use at pressures
A up to 4 atmospheres and temperatures up to 150’ is described. It is simple to build and use and its glass construction enables the to observe the of the reaction with convenience and safety. It has been used for catalytic hydrogenation when mounted on a variablespeed shaker, and Arnold [Arnold, J., Scia c e , 114, 178 (1951)] has used it to improve penetration of eelloid in embedding solutions into bones for histological sectioning, The frame of the a p p a r a t u s was made of a 5 X 19 inch piece of 0.25inch c o l d - r o l l e d steel, into which had been milled two parallel slots, 0.25 inch wide and 0.125 inch deep, 0.125 inch from the long edges. This piece, when c u t and welded together as shown in Figure 1, f o r m e d the top, bottom, and side. Into the slots were fitted two 5 X 9 inch pieces of 0.25-inch safety glass as front and back windows. In the top plate was cut a hole, 2.625 inches in diameter i n t o which t h e standard Corning flangefits. The0.5 inch hole in the bottom plates is of use if the reaction vessel becomes stuck. The heating element, G, uses about 130 watts a t 110 volts. The curve of maximum temperature us. voltage applied by a variable t r a n s f o r m e r is a s t r a i g h t line between 40 volts (80 ”) a n d 120 volts (280”). The Nichrome wire was wound on 0.5-inch a s b e s t o s tape, as recommended by Glasebrook and W i l l i a m s (Glasebrook, A. L., W i l l i a m s , F. E., “ T e c h n i q u e of Organic C h e m i s try,” Vol. IV, p. 246, New York, Int e r s c i e n c e Publishers, 1951), and was secured a t each end by fastening to a small cleat made
A
D
from glass rod, as shown. The reaction vessel comes to working temperature rapidly, usually within half an hour. To obtain a better fit of the jacket tubing, F , each piece was selected for roundness and cut to a right cylinder. The Transite blocks N , were turned by the machinist to fit the individual portions of tubing, as some in size were found. A circular gasket of asbestos cord was placed in the bottom of the outer circular groove, to act as a cushion for the tubing. The reaction vessel, M , was made of a portion of borosilicate glass pipe, 1.5 inches inside diameter, finished with a test tube seal, and thoroughly annealed. The Corning Glass Works reconlmends 50 pounds per square inch as maximum pressure t o be used; in this diameter tubing this actually includes a large safety factor, and Pressures of 60 pounds per square inch have been used without incident. Snecial heat-treated elass which is renorted to withstand much higher pressures is &ailable from the Corning Glass Works. For convenience in handling small amounts of material, such as may be found in tracer s ntheses, a centrifuge tube in a stainless steel carrier may be usegas an insert or liner. The apparatus was attached by means of rubber pressure tubing to the valve, tank, and gage assembly from a Parr pressure reaction apparatus (Model 3911, Parr Instrument Co., Inc., Moline, Ill.); other similar arrangements may be used. It is recommended that Type 347 stainless steel be used in the cover, 6,and piping, particularly if halogen-containing materials are to be used. Hydrochloric acid solutions will attack the thermometer stem a t higher temperatures, unless i t is protected by a well made of glass tubing.
If the reaction vessel is to be used for hydrogenation, care should be taken in selecting the kind of pipe “dope” used in assembling the pipe fittings, as some kinds contain catalyst poisons. Glyptal varnish has been used satisfactorily. The recommendations of James Kotora, Jr., of the Division Shop, in the design and construction of this apparatus are gratefully acknowledged. Apparatus for Observing Emulsions. W.C. Griffin and R. Behrens, Atlas Powder Co., Wilmington, Del.
examination or comparison of emulsions involves measurement of separation or creaming. The extent of such separation is often obscured because of the opacity of the layers when the samples are viewed with either diffused or reflected light. Transmitted light properly utilized permits observation and measurement with satisfactory precision. The types of containers most used in emulsion studies are heavy glass sample jars and graduated cylinders; both tend to obscure separation. Heavy glass walls cause excessive internal reflection of light. The graduation lines on cylinders cause stray reflections. Containers of large diameter make it difficult to obtain a light source of sufficient intensity to permit the observer t o see through HE
Figure 1. Glass Pressure Vessel with Heating Jacket
plate 3 required 120’ apart on 3 8 / 8 inch diameter bolt circle: screws welded to frame 1/8 inch gasket (rubber, neoprene, Koroseal, or Te0on) Borosilicate glass tubing, 60-mm. and 73-mm. diameter, each 71/r inches long Heating element, 25 turns of No. 30 gage Nichrome wire; requires 16 feet No. 20 gage stainless steel cover plate, perforated with I/a-inch holes on 8/16 inch staggered centers 1/c inch diameter X 8 inch long machine screws: 4 required 1/z X 1/n inch No. 20 gage stainless steel angle, spot-welded to cover plate No. 5-40 screws to fasten cover plate; 4 required Standard Corning flange for 11/z inch I.D. glass pipe, Corning Glass Works, Corning N . Y . 11/2 inch ’I.D. borosilicate glass pipe, Sl/a inches long I/z x 41/4 x 47/8 inch Transite, 2 reuired. anchor t o base with 26/6-18 Illen Lead cap screws (not shown) No. 18 gage parallel lamp cord, length as Silver-soldered required joint, copper to Nichrome
D. 6/16-18 screws with wing nuts: E. F. G.
H.
I. J. k’.
L. .M. S.
0.
P.
W.
Figure 1. Apparatus
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V O L U M E 24, NO. 6, J U N E 1 9 5 2
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I. .Table .
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.
Parts
...
. . .
....
i stainless steel 22.Ze.Z? channels. 8 x i x 0.5 inah 2 end plate:s.13.5 X 5.5 X 0.5 inch , 3 x 1.75 x 1.75 inohes with holes punched for tube 1 base rail, N spsoers
+
hn,inm -11 upper ..__, Eli _"
I
1 spring Pl
+
1 u ~ ~ front e r rail N a X 8.5 X spring plate attdched by d d e r i n d
+
N 1 tube spacer8 1 marrail. N + 3 x 3
u;Y5
inch ( ~ 7 t hupper glass UP ana
x
0.25 inch (with tube spacers attached by soldering) 2 end d o t cover plates as ahown to steady light 8UpPOrt rode 2 side oanel m a s h aooronmateb 8 inches h i & as shown .. ight support , 2 0.5.inoh polahedrods, N
+ 4.5inahes 1ong.ends reduced to %-inchnuts
ight housing,0.25-inch Bakelite 3 end plates 2 side plates . 1irontplatewlth%-inohslotasshown Prookets 2 showoase tubular bulhs,,clear glasa, 40-watt 1 normally own micro smtoh. 8.p.s.t. mire and plug
:lassscsle,N
Figure 2.
+ 2.5 x 8.5inehes (V/ainohthick)
Tube Rack Diagram of Tube Rack t D NOR.IILLY
the sample, and these. cantainers often have irregular bottoms. A n a p p a r a t u s based on the utilization of t r a n s m i t t e d light permits more accurate observations of the extent of creaming.
To sui7 NUYBFR W T
The apparrttus employs 50-ml. Nessler tubes or an unduated replica (available ,m A. ' A . Pesce Co., :nnett S uare, Pa., or .horatory Elass, Inc., Millle, N. J., and made from rosilicate glass, a t approxiuately one third the cost of the Nessler tubes). The apparatus shown in Fi gure 1-k used to examine one tube a t a time. The lens of a "bull's+ve" readine la!np isremoved-and replace2 a mask with a 0.26 X 3 :h slot. The tube containz the emulsion i8 held before the slot and the extent of separation noted with the light shining through the tube. A separate scale of 100 divisions must he employed t o m e a s u r e t h e
W
PLAN "A
number of tub&, madelargely from 22-gage stainless steel sheet. An emulsion viewer following this general desoription is now available (Cataloe N o . 4 9 4 3 - C , A r t h u r H': Thomas Co., West Washington Square, Philadelphia, Pa.). The emulsion t,nhes ~-... are'inserted in slots formed by spacer bars azainst which ~
FmNT ELEVATION
END E L E V A W
A NA
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LYT I CA L CHE M I S T R Y
they are snugly held by springs, and which serve as supports and as light shields to eliminate stray light. The emulsions are viewed through the glass panel in the front oi the rack. This panel is actually a glass photographic plate on which lines forming 100 vertical spaces in 7.5 inches have been printed. .In essential feature of the design is the discontinuous horizontal rulings. The light source consists of an incandescent filament mounted behind a 9 / g inch slit in a movable housing, so that it niay be positioned behind the emulsion to be examined. The slot in the front panel of the light housing is necessary to reduce stray light. The apparatus (Table I ) is assembled largely with tinner's screws. The printed glass plate is adjusted by means of screw slots in the lower glass guide, so that the zero line on the glass plates coincides with the upper side of the tube bottom. The prepared test emulsions are added to the tubes to a depth which corresponds to 100 divisions on the front glass pane! (16.75 cm., 7 . 5 inrhes), the 50-ml. graduate line on the Kessler tube not being used. After suitable aging, creaming, sedimentation, or oil separation of the test emulsions may be read as volume per cent directly from the glass screen in front of the tubes. This method provides a standard depth. The tubes are filled to an exact depth by pouring sufficieiit emulsion in the tube to give a slight excess, placing tube in viewer, and sucking out the excess emulsion with a glass tube attached to a vacuum system, adjusting the level accurately by the height at which the suction tube is held. A holder for the suction tuhe that rests on the front and rear top rails is a useful accessory. L
The ease of formation or of dispersion of an emulsion may also be estimated with the accessory tube support by holding a pipet a given distance above the surface of water in the Yessler tubes. The differences in extent of dispersion observed \Then various emulsifiable products are added in this uniform manner afford an estimate of the facility with which an emulsion may be prepared. The writers wish to acknowledge the assistance of Hon-ard Ferrier, who aided in the design of the component parts, and assembled the apparatus, and of George Huston, who prepared the drawings of the apparatus.
Q Figure 1.
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U I J
4pparatus
outside with nickel. The qtand for the receiving flmk ran I J ~ raised or lowered with one grasp. h tubing support prevents breakage of the condenser due to the weight of the heavy, waterfilled rubber tubing. Inlet tube H makes it possible to draw up mercury if the digestion procedure of Hiller, Placin, and Van Slyke [J.Biol. Chem., 176, 1401 (1948)] is used.
Warburg Vessel Rack. Roy E. Young, Division of Subtiopical Horticulture, University of Califoinia, Los .Ingeles 24, Calif. Micro and Semimicro-Kjeldahl Distillation Apparatus. Xolfgang Kirsten, Institute of 3Iedical Chemistry, University of Gppsala, Gppsala, Sweden.
,$KJELDAHL distillation apparatus which favorably compares with other apparatus in speed and accuracy has been constructed in this laboratory. It is commercially available ( S o r stedt 8: Soner, Stockholm) and is in use in several Swedish laboratories. The layout of the apparatus is shown in Figure 1. -4 is an elect,rically heated boiling bottle with a three-stage switch, one for heating, one for distilling, and one for keeping hot (during lunch, etc.). G is a three-way st,opcock ryith one opening to L and one through J into a bottle or a sink. S is a spring rvhich holds joint N in position. Procedure. After the apparatus has been steamed out, G is turned so that the steam leaves through J . Stopper E is taken out and D is opened. The receiving flask, I , is placed under condenser C. The sample is introduced through E , followed by the sodium hydroxide. E is closed and the funiiel is filled with water. G is then turned so that the vapor passes through the distilling flask and D is closed. The distillation is finished after 5 minutes. Z is lowered, G is turned so that the vapor passes out through J ,and stopper E is taken out. Within 3 seconds all liquid from K has been drawn into L and the water from E has washed K and has also been drawn into L. D is opened, the next receiving flask is placed under C, and thc next sample is introduced and distilled in the same manner. The water in A boils continuously and no time is therefore lost in bringing it to boil or allowing i t to cool for draining of the apparatus. The time during which the distillation is going on can be used for the titration or for operating a second apparatus. Experienced analysts can operate three units at the same time. Joint N and stopcock G should be lubricated carefully with silicone grease. The apparatus is made from borosilicate glass; the boiling hottle is of copper which is plated on the inside with tin, on the
troublesome featui es encountered with Kai bui g equipment have been eliminated in this laboratory hy the ube of the vessel rack desciibed. breakage of vessels, tipping over of the vessels when they are being filled, and maintaining the ~ . e s ~and I s plugs in order.
S
CVERAL
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-I
The vessel rack is shown in the diagram. I t is best made of stainless steel, which is easily cleaned and not damaged by accidental spillage of acid used in cleaning the vessels, but it may be made of aluminum with spring brass vessel clips. Ten vessels can be clipped to each rack, the renting plugs being placed in holes on one side and stopper plugs on the other side. Exact measurements are not given because the dimensions chosen n ill depend on the type of equipment used and the size of drying oven available. The size shown n-as made because six racks would fit in the drying oven available, and two racks of ten ves,.cls would fill the circular bath used. Plastic covers may be made t o cover the racks when they are not in use.
