Rising bubble apparatus

Results for single rising bubbles of a known volume were reported by Massimilla et al. [49]. The apparatus consisted of a fluidized bed column 3.5in I.D. Several types of particles were used - glass beads 0.79mm, 1.09mm - iron sand 0.2mm - silica sand 0.22mm. Water and air were employed as the liquid and gas phases, respectively. It was found that the relationship between the diameter of a single bubble and the bubble velocity was affected by the state of expansion of the liquid-solid bed and was almost independent of particle size and density. 

Fig. 32). Using a fine pipette insert about i cm. length of the liquid into the bottom of the tube. Now place in the tube A a fine inverted melting-point tube B of about i mm. diameter, sealed at the upper end. Fasten the capillary tube to the ther- Fio. 32. mometer by means of a rubber band and place in a melting-point apparatus. Heat slowly until a stream of bubbles rises from the bottom... 

The term still is applied only to the vessel in which liquids are boiled during distillation, but the term is sometimes applied to the entire apparatus, including the fractionating column, the condenser, and the receiver in which the distillate is collected. If a water and alcohol distillate is returned from the condenser and made to drip down through a long column onto a series of plates, and if the vapor, as it rises to the condenser, is made to bubble through this liquid at each plate, the vapor and liquid will interact so that some of the water in the vapor condenses and some of the alcohol in the liquid vaporizes. The interaction at each plate is equivalent to a redistillation. This process is referred to by several names in the industry namely rectification, fractionation, or fractional distillation. 

The American Journal of Science for 1840 described an amazing phenomenon caused by this kind of gas. At West Town, Chester County, Pennsylvania, the students of the boarding school used to bathe in a mill-pond supplied by Chester Creek. Rising from the creek were countless bubbles of gas from decaying leaves and wood (25). "I first visited the place in the year 1834, said Moses Lockwood. Taking as apparatus a bell-glass furnished with a stop-cock and a taper, and as companion an assistant teacher. . ., we proceeded to the pond, readily filled the... 

In both the gassed (aerated) stirred tank and in the bubble column, the gas bubbles rise through a liquid, despite the mechanisms of bubble formation in the two types of apparatus being different. In this section, we shall consider some common aspects of the gas bubble - liquid systems in these two types of reactors. 

Experiment 38. — Fill the Hofmann apparatus, Fig. 41, with water containing 10 per cent of sulphuric acid so that the water in the reservoir tube stands a short distance above the gas tubes after the stop-cock in each has been closed. Connect the platinum terminal wires with a battery. As the action proceeds, small bubbles of gas rise and collect at the top of each tube. Allow the current to operate until the height of the gas in the smaller tube is from 8 to 10 cm. Measure the... 

Air bubbles rising through a liquid have been used in viscometry. the Cochins apparatus the number of seconds taken by an air bubble to rise, in a 50 cm. tube of liquid is measured for wide tubes this is independent of the size of the bubble within wide limits. 

---