INDUSTRIAL AND ENGINEERING CHEMISTRY
462
An Improved Thermometer MARSHALL B. STANDING AND JAMES H. WIEGAND University of Michigan, Ann Arbor, Mich.
A
VOL. 11, NO. 8
and inside diameter the same as drilled in the body, is slipped on the thermometer above the stopper to prevent the stopper’s jamming into the body and turning the thermometer as the guard is screwed on. The assembled guard may be screwed on a 3/~-inch nip le which is in turn screwed into a tee, but a much neater method for permanent installations is shown in the figure. A short length of S/s-inch pipe, J , threaded at one end, is brazed or welded into a hole drilled in the main pipe, F , as shown.
COMMON laboratory problem is the installation of thermometers so that they may be easily removed and
An Alkalimeter
at the same time well guarded. In the course of research it was necessary to install ten thermometers on a double-pipe heat interchanger and a guard was developed which is believed t o have considerable merit.
W. HEINLEN HALL Bowling Green State University, Bowling Green, Ohio
The complete guard is shown in Figure 1. The body of the guard, B, is a 1-inch length of ’/*-inch hexagonal brass stock, drilled and tapped for a standard 3ls-inch pipe thread. At the bottom of the tapped hole a concentric hole is drilled through of a diameter a t least inch greater than that of the thermometer, C, being installed. I n addition, three holes are drilled for 3/16-inch welding rods, D, which constitute the guards. These rods, of proper length, are threaded or soldered in place and a short piece of 1/3-inch pipe, E , is brazed or soldered inside the rods as shown. For the packing, about 3/10 inch is cut from the large end of a No. 00 one-hole rubber sto per, so that the remainder, G, will not bind in the threads d e n on the thermometer. Last, a washer, H , with g/~e-inchoutside diameter
4
Drying “J” Wafer-Aqm‘rafor Tube (%be Trap
-.
T
HE indirect determination of carbon dioxide b y means of a simple alkalimeter merits consideration whenever extreme accuracy is not required and speed is of some importance. Such a n alkalimeter of somewhat original design has been used with considerable success in the author’s laboratory for the past 3 years. In it are incorporated the advantages attending the use of any of the newer high-efficiency solid desiccants (such as anhydrous calcium sulfate), instead of concentrated sulfuric acid, as well as those arising from the elimination of stopcocks,
A FIGURE 1. DETAILSOF GUARD
A is an ordinary 25-cc. distilling flask with a part of the neck cut off. B and C are ordinary test tubes shortened and drawn down. All pieces should be selected for lightness, since it is desirable that the apparatus weigh as little as possible. Ordinary rubber stop ers are used. The weigged sample (about 1.5 grams in the case of limestone) is placed in A . The desiccant is placed in B. Slightly more than enough acid to react completely with the sample is placed in tube C. The entire apparatus is assembled, small plugs being placed in the tubes leading from B and C. The whole piece is then weighed accurately. Drying tubes containing the same desiccant as that used in the apparatus are attached to B and C . To the drying tube attached to B are connected a T-tube, a water trap, and an aspirator as indicated.
