Jan., 1916
T H E J O U R N A L OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
t o n Bluestem; C a very weak Western Club wheat p a t e n t ; *D a strong First Clear milled from hard spring wheat; a n d E a n unusually strong, hard spring wheat Second Clear. I t will be noted t h a t while t h e flours stand in t h e same order with respect t o volume of loaf a n d maximum expansion in t h e expansimeter, t h e 'atter accentuates t h e differences much more distinctly t h a n does t h e volume of t h e loaf. The relative texture of t h e loaf also serves as a check on t h e expansimeter test. Thus, while t h e loaves baked from flours B and C were practically t h e same in volume, t h e difference in texture was very striking, a n d paralleled t h e test of maximum expansion. Sample E, whi e strong and capable of yielding loaves of reasonably good texture, was found t o be very dark in color. The same was true of D, although t o a lesser extent. TABLEI-RESULTS OF TESTS OR FIVEFLOUR SAMPLES MaximFm Absorption of expansion Volume water per 100 of loaf g. of dour Color in cylinder score Texture Sample cc. cc. cc. 101 100 1,480 64.0 A 930 90 B 720 1,320 60.2 98 97 70 C 600 1,310 54.4 94 1,430 65.6 85 D 910 92 990 1,560 64.7 55 E SUMMARY
The method outlined is believed t o eliminate t h e personal equation so far as is practicable in making actual baking a n d expansion tests. The use of a machine for mixing, t h e automatic recording of maximum expansion in t h e cylinder, a n d t h e raising of t h e dough t o a fixed height before baking all tend t o render t h e element of judgment less prominent t h a n has heretofore been t h e case with most methods. Automatic regulation of t h e temperature in t h e fermentation cabinet also contributes t o t h e ease of making t h e tests. The use of such appliances a n d methods tends t o render t h e making of baking a n d expansion tests less a n a r t a n d more a science. CEREALAND FLOURLABORATORY DIVISIONOF AGRICULTURAL CHEMISTRY EXPERIMENT STATION MINNESOTA AGRICULTURAL UNIVERSITY FARM,ST. PAUL, MINNESOTA
A CHECK VALVE FOR SUCTION FLASKS B y G. P. WALTON' Received July 14, 1915
I n those determinations involving filtration through a Gooch crucible where rejection of t h e filtrate is permissible, i t is a frequent practice t o filter in sets of from ten t o fifty. Often t h e time allowable for filtering a set is limited. This requires not only rapid filtering, b u t the shortest possible interval between successive filtrations. Under such conditions t h e frequent interruptions occasioned b y t h e necessity for disconnecting a n d emptying t h e suction flasks are a source of no little inconvenience. T o obviate this t h e writer has devised a form of ball check valve which may be readily fitted t o any of t h e usual types of suction flask. The valve shown in detail in t h e figure has been used in this laboratory for several months a n d has satisfied all requirements. It consists of a glass tube ( A ) having a n indentation or other check for t h e 1
Assistant Chemist, Cattle Food and Grain Investigation Laboratory.
57
ball-valve; a glass ball valve with guide (D)blown from a piece of capillary t u b e ; a n inner glass t u b e ( B ) ; a n d t h e valve-seat ( C ) , a short piece of smooth heavy rubber tubing with square cut ends. The parts are shown assembled a n d fitted t o t h e usual form of suction flask ( E ) . A drain tube, not shown, -.-a$"
L-.-.
t'
A
E
completes t h e apparatus. It is obvious t h a t when a Gooch crucible is placed in t h e holder in t h e top of t h e flask a n d suction applied, the ball ( D ) will be drawn tight against the rubber valve-seat. Upon releasing t h e vacuum t o remove t h e crucible, t h e height of t h e column of filtrate in the flask will immediately cause t h e ball t o be forced out, allowing t h e liquid t o be completely drained off. It has been found t h a t comparatively slight suction is sufficient t o close t h e valve perfectly, while upon releasing t h e suction, a column of liquid in t h e flask a fraction of a n inch above t h e valve is ample t o start t h e outflow. T h e several parts of t h e valve are readily made a n d quite durable, t h e rubber valve-seat lasting for several months with constant use in this laboratory. While t o have the valve made wholly of glass would appear t o be advantageous, i t has been found difficult t o construct one in which t h e ball will always seat itself so as t o make t h e ground joint air-tight, a n d yet not be liable to stick in the valve-seat upon releasing t h e vacuum I n t h e form of suction-flask not provided with a n outlet at t h e bottom, a suitable vent may be drilled using a short section of copper tube in a drill press with carborundum a n d water for abrasive. T o adjust t h e valve, force t h e rubber (C) through t h e vent, moisten t h e inner tube ( B ) a n d push i t through t h e rubber making a tight joint between t h e latter a n d t h e wall of t h e flask; place t h e ball ( D ) in position and force t h e outer t u b e ( A ) over t h e rubber. The rubber should project about 1 / ~ 6 ' ' in. beyond the end of t h e inner glass tube, which serves merely as a siphon and brace for the valve-seat. A check valve of t h e form described has proved a great convenience a n d time saver when making t h e final filtrations in such determinations as those of crude fiber, reducing sugars, pentosans a n d any others wherein filtrate a n d washings are rejected. BUREAUOF CHEMISTXY DEPARTMENT OR AGRICULTURE WASHINGTON, D. C
