A Locknut for a Weight Buret hIARTIN KILPATRICK, University of Pennsylvania, Philadelphia, Penna.
I
S THE use of weight burets in this laboratory the problem of keeping the ground cup in place during transfer to and from the balance has been solved as described below. The buret itself is similar to that outlined by Shedlovsky and Brown ( I ) , being without a stopcock a t the bottom; the additional feature is the “locknut” device sho-m in the diagram, b y which the cup is held in place.
C
A is a vertical section through the slotted bell-shaped apron fused on the buret above the ground-glass joint for the cup. Below it is a section of the cup. The sections were made in the following manner: The left half of each of these two sections represents the section cut by a vertical plane whose direction is represented on drawing B by its trace, which is the radius to E. The right half represents the section cut by a plane whose trace is the radius to F . This was done in order to show clearly the position of the slots in the foldedunder edge of the bell-shaped apron. The slots are actually on opposite ends of a diameter, as shown in horizontal sections B and C, taken through X Y with the cup in place. Horizontal section B shows the buret as the wing 1, is slipped into the slot at l’, and C shows the same section after a rotation of the cup through 90”.
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B
At all positions except that illustrated in B , the cup is firmly locked in place, and cannot fall off. The same design can be adapted to burets with stopcock a t the bott,om by constructing the bell just below the stopcock.
Literature Cited (1) Shedlovsky and Brown, J . Am. Chem. SOC.,56, 1066 (1933).
Laboratory Juice Extractor GEORGE W. IRVISG, JK., AND THEODORE W. LORING Department of Biochemistry, Cornell University Medical College, New York, N. Y.
IN
BIOCHEMICAL investigations it is frequently necessary to effect a rapid and fairly complete separation of fluids from animal or plant tissues. Recently, the authors were confronted with the necessity of making such a separation in connection with work upon the hormones of the posterior lobe of the pituitary gland. I n this instance they wished to make a purely mechanical separation of the fluid contained in fresh glands from the gland tissue. F I G ~ R1.E CROSSS E C T I O N ADLI A GRAM OF JCICE EXTRACTOR
A fairly satisfactory separation was accomplished by means of the 2.25-inch test cylinder of the familiar Carver laboratory press. The gland material w s thoroughly macerated with sand
and the fluid was expressed by subjecting the ground mass to high pressure in the test cylinder. The press juice, together with the viash fluids, was found to contain the active material desired in almost quantitative yield, while the press cake of sand and residue contained only traces of activity. Extensive use of the Carver equipment for this purpose revealed several disadvantages. In using the Carver test cylinder, the material to be pressed was placed in the cylinder between two felt filter disks and the fluid v a s expressed by applying pressure to the piston. Since the bottom of the cylinder is not perforated,
A , piston; H , cylind e r ; K ,base; F , removable, perforate: steel plate; B a n d B , channels in cylinder a n d base, sloped tow a r d t h e vertica) and D , channel, C; felt filter disks; E , material t o be pressed; G , spout through which e x p r e s s e d f l u i d is collected
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SEPTEMBER 15, 1940
ANA4LYTICALEDITION
a large part of the expressed fluid escaped between the piston and the cylinder and flowed down the sides of the cylinder during the pressing operation. Ordinarily, the liquid expressed in this manner can be collected as it flows from the drain hole in the platform of the press, but in the authors' case means for making a more quantitative collection of the fluid and for avoiding its contamination were desired. By placing the test cylinder in the metal pan provided as part of the Carver equipment, losses can be largely avoided, but even this procedure is not entirely satisfactory or convenient, especially in the treatment of small amounts of tissue. To answer their needs in this respect the authors have devised a modified juice extractor (in cooperation with the American Instrument Company, 8010 Georgia Ave., Silver Spring, Md. The equipment is designed for use with the usual type of hydraulic laboratory press.). The new extractor is well adapted to laboratory pressing operations where relatively small amounts of material must be handled and where both the press cake and the press liquid must be carefully collected with a minimum of loss and contamination.
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A cross-sectional diagram of the improved extractor is shown in Figure 1. The apparatus is constructed of steel and consists of four separate parts : base, perforated plate, cylinder, and piston. To operate, the base, perforated plate, and cylinder are assembled as shown in the diagram and a circular felt disk is placed on top of the plate. The cylinder is filled to a suitable depth (found by trial) with the material to be pressed and the material is covered by a second felt disk. The piston is placed in the cylinder and the entire extractor is placed on the platform of a Carver laboratory press where pressures up to 20,000 pounds can be applied. During the pressing operation most of the expressed fluid passes through the perforated plate a t the bottom of the cylinder and is expelled through the spout. Any fluid which is forced between the piston and the cylinder, or through the joint between the cylinder and the base, is collected in the channels provided and eventually flows out through the spout. After the fluid has been completely expressed, the cylinder is simply lifted from the base, the press cake is ejected by means of the piston, and the apparatus is ready for use with a second lot of material. For best results the felt filter disks should be renewed frequently. A hole through the top of the piston handle, in which a metal rod may be inserted, facilitates removal of the piston.
A Versatile Gas Saturator WILLIAM R. RINELLI AND KARL S. WILLSON Ansul Chemical Company, Marinette, Wis.
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ARKHAM ( I ) has described a gas saturator claimed to
be more satisfactory than the commercial Friedrichs or Milligan gas-washing bottles. Equipment of this type can be used t o saturate a gas with the wash liquid, or scrub out one or more constituents of a gas stream, using a n appropriate liquid. Perhaps less well known is the possibility of removing undesirable dissolved gas from a liquid by bubbling another noninterfering gas through it. A wash tower, which is based on a somewhat different principle than that of Xarkham, in several modifications has proved highly satisfactory in the authors' laboratory during the past few years.
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Basically, the tower is designed to pass the liquid-gas mixture through beads, helices, rings, or irregular fragments of suitable material held in place, for example, by indentations made by pressing the end of a file into the heated glass wall. Greater agitation is secured than in the spiral bottles referred to above. Liquid is circulated in both types, but in the authors' tower, if rubber tubing connections are satisfactory, several reservoirs such as R (Figure 1, A , B ) may be used to provide any desired total volume of wash liquid. The path of circulation of the liquid is indicated by arrows. A bottle of any required size can be readily connected to replace the reservoir, as shown in C. The apparatus may be easily cleaned without dismantling by filling with water and draining as often as necessary.
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FIGURE 1
Where glass-blowing facilities are limited or where i t is necessary to thermostat the tower, the modified form shown in Figure 2 has proved satisfactory. Glass seals may replace the rubber stoppers where desired. The entire unit may be placed in a larger tube, through which a constant-temperature liquid is circulated, or the entire tower could be placed in a tall thermostated bath. The tower may be readily modified to fit specific needs. Recently it became necessary to wash large quantities of a n
