Furnaces batch

Bastnasite [12172-82-6] Bastnasite [68909-13-7] Batch crystallization Batch dyeing paper Batch esterification BATCHFRAC Batch furnaces Batch injection analy ... 

Batch Furnaces, Other Furnace Types, and Kilns. 12-45... 

Continuous Furnaces Continuous furnaces are employed for the same general duties cited for batch furnaces. Units are gas, oil, or electrically heated and utihze direct circulation of combustion gases or muffles for heat transfer. Continuous furnaces frequently have an extension added for cooling the charge before exposure to atmospheric air. 

Batch Furnaces This type of furnace is employed mainly for the heat treatment of metals and for the drying and calcination or ceramic articles. In the chemical process industry, batch furnaces may be used for the same purposes as batch-tray and truck dryers when the drying or process temperature exceeds 600 K (620°F). They are employed also for small-batch calcinations, thermal decompositions, and other chemical reactions which, on a larger scale, are performed in rotary Idlns, hearth furnaces, and shaft furnaces. 

Batch esterification, 10 478—480 Batch experimental reactor, 21 352 Batch extraction, 10 756 Batch extractor, holdup in, 10 764 Batch fermentation, 10 267 Batch filter cycles, 11 344, 345-346 Batch furnaces, 12 288—289 Batch gasoline blending, 12 413 Batch hydrogenation, 10 811 Batching, ceramics processing, 5 648 Batch injection analysis (BLA) technique, 9 586-587... 

Fig. 9.7 Typical pressure and temperature profiles of a vacuum sintering cycle in a batch furnace [B.25].

Since batch furnaces are normally relatively small and can be controlled easily, they are also commonly used for development work. For the sintering of ceramic or powder metal parts the results from small scale testing can be directly transferred to larger or continuously operating kilns. 

More sophisticated and higher temperature batch furnaces include muffle, bell, elevator, or pit designs [B.97]. Tab. 6.7-6 lists the processes occurring during the sin-... 

For high-quality wares, temperature control is very important to avoid the above mentioned problems in different processing stages. This can be accomplished easiest and most accurately in batch furnaces. Some materials must be, at least during certain stages, fired in reducing or other special atmosphere that is also best provided in batch kilns. However, many bulk ceramic products need to be of such low cost that continuous furnaces must be used, which operate more economically. 

Batch Furnaces This type of furnace is employed mainly for the... 

FIGURE 9.1 Gas-fired batch furnace used in a commercial glass blowing operation. 

FIGURE 9.4 A large batch furnace used in the production of traditional ceramic products. 

In higher temperature furnaces, the interradiation from hotter solid surfaces to cooler surfaces tends to self-correct minor nonuniformities. For example, in batch furnaces and ovens, the door end and back end incur the greatest heat losses. In one instance it was found that in an 1100 F (593 C) oven, a 150°F (83°C) differential was sufficient to level out the temperatures from center to each end. However, in a 2250 F (1232 C) furnace, only a 70°F (39°C) difference was necessary to level out the temperatures (because of the 4th power effect in the Stefan-Boltzmann radiation... 

Many parts of chapter 4 on continuous furnaces contain useful information that also applies to batch furnaces, but they are not included here (to keep this book compact). Readers are advised to smdy both chapters 3 and 4. 

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