T H E J O U R N A L O F I N D U S T R I A L An’D E N G I N E E R I N G C H E M I S T R Y
1’01. 9, NO. 8
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FIG. 11-DETAIL OF STIRRING HEAD
FIG.I-CARBONATING SET-UP
stirrer-shaft. This gas inlet through J is connected with a pressure gauge, G, a n d also with a union, N , serving t o connect with a source of compressed carbon dioxide gas. The globe-valve 0 controls t h e admission of gas. A continuation of J through control-valve L leads t o exit t u b e M , where gas may be withdrawn as desired. OPERATION
T h e apparatus used for impregnating with carbon dioxide consists of a carbon dioxide cylinder, pressurereducing valve, t h e stirring apparatus described above, a champagne bottle, a n d a small motor, as shown in Fig. I. First, t h e liquid is placed in t h e bottle, a n d chilled, if desired. Attachment of t h e stirring-head t o t h e bottle is made as follows: Holding t h e tines A d together they are passed through t h e central hole of a slotted plate, which then slides on u p over sleeve C, and is held firmly i n place b y a one-hole rubber stopper which serves as a heavy gasket closing air-tight t h e mouth of t h e bottle when t h e standard-clamp screws are brought u p into t h e slots of t h e plate ( 1 2 0 ’ apart) a n d screwed tight t o place as shown in Fig. I. T h e bottle with attached stirring-head is packed in ice a n d t h e pail is placed in position, t h e bottle being held securely by a clamp. (Upward thrust of t h e pulley due t o gas pressure in t h e bottle is prevented by a glass rod which acts as a top-bearing.) A flexible pipe from t h e carbon dioxide cylinder is connected with t h e union N , a n d a belt run from t h e pulley-wheel H of t h e stirring-head t o t h e motor. Gas is turned on b y opening t h e cylinder-valve a n d t h e globe-valve 0, t h e motor started a n d carbonation continued as long as desired for t h e experiment. During t h e process of carbonation, t h e collar Q is turned back sufficiently t o allow free rotation of t h e shaft B . This entails a slight gas leak, b u t t h e source of pressure being practically infinite by comparison, t h e operation of t h e machine is not affected. If a high degree of purity of carbon dioxide in t h e finished liquid is desired, control-valve 0 should be
closed, valve L opened a n d gas allowed t o run out of exit tube M . The valve L is then closed, valve 0 opened, a n d carbonation resumed. This “blow-off ” of top gas from t h e bottle sweeps out foreign gases, especially nitrogen and oxygen collected above t h e liquid and should be repeated several times t o secure t h e best carbonation. AS soon as t h e carbonation process is finished, t h e collar Q is screwed down tight a n d t h e valve 0 closed. I n practice we have found t h a t with t h e packing used in t h e stuffing-box and valves we are able t o hold a pressure of 7 j lbs. per sq. in. for several weeks. DEPARTMEKT OF AGRICULTURE BL-REAU OF CHEMISTRY. WASHINGTON. D . C.
A SAMPLING PRESS’ B y W. BLAIR CLARK^ Received March 16, 1917
Any device used in t h e preparation of samples for t h e ordinary run of analytical work should meet each of t h e following conditions as completely as possible: i t should reduce all t h e constituents of t h e substance under investigation t o particles of approximately equal size, and these particles should be fine enough t o be acted upon promptly b y whatever solvents or extractive liquids are t o be used subsequently; in t h e process of reduction no p a r t of t h e sample should be lost by spurting or otherwise; a minimum of t h e sample should be retained in t h e mechanism, a n d i t should be possible t o remove this minimum without contamination a n d in such a manner t h a t , if desired, i t m a y be added t o t h e main bulk of t h e sample; t h e apparatus should be capable of rapid operation; and, finally, i t should be easily taken apart for cleaning. It is believed t h a t t h e press here described fulfills these requirements quite satisfactorily as applied t o t h e sampling of roots, tubers, melons, a n d such fruits as are easily separated from t h e seeds and skins, especially when t h e last mentioned are of t h e tough, thick sort. Published by permission of the Secretary of Agriculture. Biochemist, Office of Cotton, Truck and Forage Crop Disease Investigations. 1 2
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T I I A J O I ‘ K X A L O F I N D U S 1 ‘ K I A L -I N I I l
