Glasses, sealing combinations

Selenium copper also available for combining high electrical conductivity with free-machining and hoi-working properties. Alloy makes excellent copper-to-glass seals. 

If it is desired to carry out the combined operations of stirring, refluxing, and addition of a liquid in a stream of gas, the apparatus of Fig. 77, 7, 12, a may be used the side tube for the gas is sealed on to the separatory funnel. For the passage of a gas into a stirred liquid, the aperture carrying the modified separatory funnel may be fitted with the device shown in Fig. 77, 7, 12, 6 the glass rod inside the tube is held in position by a short length of heavy-wall rubber tubing and is employed to clear the lower end of the gas delivery tube, should it become blocked with solid reaction product. 

The most widely used sterilization method ia the food industry is moist heat. The heat is usually suppHed by high pressure steam, but because most foods already contain moisture the role of steam is to heat the food to the required temperature. The cooking and sterilization processes can frequendy be combined into one. The food may be sealed into impervious containers of glass, metal, or plastic film and undergo terminal sterilization, or it may be presterilized in batches or in a continuous operation and then filled into a presterilized container. The latter process is called sterile filling. 

Glass electrodes are now available as combination electrodes which contain the indicator electrode (a thin glass bulb) and a reference electrode (silver-silver chloride) combined in a single unit as depicted in Fig. 15.2(h). The thin glass bulb A and the narrow tube B to which it is attached are filled with hydrochloric acid and carry a silver-silver chloride electrode C. The wide tube D is fused to the lower end of tube B and contains saturated potassium chloride solution which is also saturated with silver chloride it carries a silver-silver chloride electrode E. The assembly is sealed with an insulating cap. 

A further combined characteristic that a glass and a metal must have before they will form a seal, over and above that of the provision... 

The contents of the flask are then poured upon 600 g. of cracked ice, and, with hand stirring, 75 ml. of hydrochloric acid (sp. gr. 1.18) is added. The cold mixture is now filtered through glass wool in an ordinary funnel into a 2-1. separatory funnel. The aqueous layer is separated and extracted once with 250 ml. of ether (Note 7). The combined extract and main product are dried over 30 g. of calcium chloride, the ether is removed on a steam bath, and the residue is distilled using a 500-ml. modified Claisen flask.6 The selenophenol is collected at 57-59°/8 mm. or 84-86°/25 mm. the yield is 43-54 g. (57-71%) (Notes 6 and 9 through 14). The product should be sealed at once in a glass vial (Note 8). 

Inorganic solid wastes, particularly those containing toxic metals and toxic metal compounds, used Raney nickel, manganese dioxide, etc. should be placed in glass bottles or lined fiber drums, sealed, properly labeled, and arrangements made for disposal in a secure landfill. Used mercury is particularly pernicious and small amounts should first be amalgamated with zinc or combined with excess sulfur to solidify the material. 

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