Water-glass, for sealing

Water glass asbestos joints, 5, g, 8, 46 Water glass, for sealing, 5, 7 Williamson reaction, 6, 48 Wool, 5, 40... 

Immersion electrodes are the most common glass electrodes. These are roughly cylindrical and consist of a barrel or stem of inert glass that is sealed at the lower end to a tip, which is often hemispherical, of special pH-responsive glass. The tip is completely immersed in the solution during measurements. Miniature and microelectrodes are also used widely, particularly in physiological studies. Capillary electrodes permit the use of small samples and provide protection from exposure to air during the measurements, eg, for the determination of blood pH. This type of electrode may be provided with a water jacket for temperature control. 

An interesting application of sprayed aluminium is for resistance to high-temperature oxidation up to 900°C. The article is grit-blasted and aluminium sprayed, usually to a thickness of 0-008 in (0-2 mm). It is then treated with a sealing composition which may be bitumen or water-glass, and is diffusion annealed in a furnace at 850 C for approximately 30 min. The final coating... 

Stirrer, mercury seal, 7, 80 Stoppers, asbestos and water glass 5, 9 Stopper protection, tin foil for rubber, 4, 68... 

The vapor pressure at 0° (43 mm.) is generally a sufficient criterion for purity. (The checkers also used infrared spectroscopy and noted a trace of impurity of silicon tetrachloride.) Elemental analysis is readily accomplished by heating a weighed sample at 160° for 18 hours with a slight excess of water in a sealed glass tube. A 15 to 20% excess of water over that required by the equation ... 

A. 1,4-Diphenyl-5-amino-l,2,3-triazole. A 500-ml. three-necked flask is equipped with a sealed stirrer, a thermometer well, and a dropping funnel which is protected by a drying tube and has a pressure-equalizing side arm. A mixture of 35.7 g. (0.3 mole) of phenyl azide (Note 1) and 38.6 g. (0.33 mole) of phenylacetonitrile (Note 2) is placed in the flask. The flask is immersed in an ice-water mixture contained in a 1-gal. Thermos flask. After the reaction mixture has cooled to about 2°, a solution of 24.3 g. (0.45 mole) of sodium methoxide (Note 3) in 150 ml. of absolute ethanol is added dropwise during the course of 2 hours. The reaction mixture is then stirred at 2-5° in the ice-water bath for a period of 48 hours (Note 4). After the cooling bath has been removed and the flask allowed to warm spontaneously to room temperature, the mixture is filtered by suction on a sintered glass funnel, and the col-... 

The filtros plate for filtration can be very conveniently sealed into the Buchner funnel with a paste of water-glass and amorphous silica which is then hardened with concentrated sulfuric acid. 

Fig. 1. A, 4-mm. stopcock B, thickened for easy sealing C, water inlet D, water outlet , this seal can be replaced by a ground glass joint for higher-boiling materials than butadiene F, filling level G, the cooling water tube indicated by the dotted lines will permit a higher flow rate if shaped as an oval or rectangle B, reaction well I, lamp well J, cooling water jacket.

Tourills are in principle Wolff s ceramic (stoneware) bottles, provided with two large connections at the top in which elbow pipes are fixed and sealed by a mixture of asbestos and water glass. The pipes serve for inlet and outlet of the gases (see Fig. 118). 

The elect rolytic vessel (see Fig. 142) is made of stoneware and built for a load of 750 A. The internal dimensions arc 615 X 500 X 520 mm. It is divided by partition 2 into two compartments. Each compartment is divided by diaphragms 3 into t wo anode spaces A and three cathode spaces B. In the anode spaces cooling water flows through glass tubes sealed at the bottom. 

---