Air furnaces

Ferrous foundries consist of two types steel foundries in which electric furnaces (EAF and induction) are used, and iron foundries in which hot-blast cupolas and/or electric furnaces are used. Electric furnaces use virtually 100% scrap charges. Cupolas are shaft furnaces which use preheated air, coke, fluxes, and metallic charges. Scrap is over 90% of the metallic charge. Cupolas accounted for about 64% of total iron foundry scrap consumption in 1994 and electric furnaces accounted for about 34%. The balance was consumed by other furnaces, such as air furnaces. Iron foundry products have a high carbon content and the scrap charge usually contains a high percentage of cast iron or is used in combination with pig iron. 

Dry processes materials handling, air separator (hot-air furnace) Particulates (dust) Local exhaust system with mechanical collectors and baghouse... 

A Tube Furnace.—Various forms of furnace are used. Those which are heated on the principle of the Lothar Meyer hot-air furnace by a number of pin-hole gas jets are easily regulated, and can be raised to a high temperature. The Gattermann furnace, shown in the diagram (Fig. 20), is a very convenient form. 

Wind-kanal, m. air passage, air duct, -kastea, m. wind chest, air chamber Metal.) twyer box. -kessel, m. blast pressure tank, blast box air chamber, -leitung,/. Metal.) blast main, -leitungsrohr, n. Metal.) blast pipe, -messer, m. wind meter, anemometer blast gage, -miihle, /. windmill, -ofen, m. wind fiirnace, air furnace, -ppcken, f.pl, chicken pox. -pressung, /. Metal.) blast pressure, -lohr, n. Metal.) blast pipe, twT r pipe, -sammler, m. air reservoir, compressed-air tank. 

Conventional hot-air furnaces, similar to those found in homes, are often used in laboratories. A university campus or an industrial plant may have steam available, which can be conveniently put to use for heating. 

Once the energy - in many cases, heat - is generated, it must be transmitted to the fuel (the "touching" of the fuel and energy legs). This process is accomplished in three ways conduction (die transfer of heat through a medium, such as a pan on a stove s heating element), convection (the transfer of heat with a medium, such as the heated air in a hot-air furnace), and radiation (the transfer of heat which is not dependent on any medium). 

Gas-phase experiments at 155 °C. were carried out in a 250-ml. cylindrical Vycor reactor in a hot-air furnace. Later experiments were done in a 500-ml. borosilicate glass flask heated in an oil bath. With either system, di-terf-butyl peroxide, oxygen, and isobutane were metered into the reaction vessel in that order by expansion from the vacuum line the pressure of each component was measured using a mercury or oil manometer. Mercury vapor was excluded from the reaction vessel. 

Heating equipment, except electric and warm air furnaces... 

The CPVC wetcake leaves the product centrifuge at 80°C and 1 atm and is fed to the elevated end of a rotary dryer (a rotating cylinder inclined about 35° from horizontal). A fresh air stream at 2TC. 1 atm, and 60% relative humidity is mixed adiabatically with an air stream recycled from the dryer exhaust, and the combined stream is healed in an air furnace and fed to the lower end of the dryer. Water evaporates from the wetcake moving downward in the rotating drum into the hot air moving in the opposite direction. The exhaust air leaves the dryer at 110°C, 1.3 atm, and 20% relative humidity. The dryer operates adiabatically. Ninety percent of the exhaust air is recycled, and the rest is vented to the atmosphere. The dried polymer resin leaves the dryer at 120°C containing 0.1 wt% water. 

Application Examples Room, office Domestic refrigerator Large refrigerators Hot air furnaces Air-conditioning ducts... 

Sintering studies were performed both to evaluate the sintering behavior of the aluminas, and also to identify conditions that produce fully dense compacts for subsequent study. Sintering was performed in both vacuum furnaces and in air furnaces for varying times at temperatures between... 

Calcination Forced air furnace Rotary kiln Fluidized beds... 

Alloys were forged in such a way [6], Their blanks were turned to cylinders of 58 mm diameter, sealed in steel pipe and heated at first from room temperature to 900 °C in electric air furnace together with it during 1 hour. After that blanks were carried manually from the electric furnace into gas one where they were heated up to 1100 °C. Blanks heated at this temperature for 1 hour were forged manually to 90% power of deformation. 

Once it has left the reactor, the wire may be either collected directly on the take-up via the drive assembly or returned to the resin tank for application of another layer of insulation via the pulley in Figure 3. Three layers of insulation are usually applied to the wire before take-up. Typical formulations for the experiments contain about 1% of a processing aid—e.g.y Nuosperse 657 (Nuodex Products Co.). Without the processing aid, the formulations wet copper poorly and bead on the wire. The processing aid is used to smooth the resin and furnish a uniform thickness of insulation. Surface contaminants on the conductor affect the continuity of the insulation. A forced, hot-air furnace serves as a simple method of pretreatment. The resin polymerizes in the photo-... 

The titania-silica (1 1 mole ratio) mixed oxide support was prepared by homogeneous precipitation method from acidified mixed solutions of sodium metasfiicate and titanium tetrachloride using urea as the neutralizer [11,12]. More details are described in a previous publication [12 ]. The Ti(OH)4 - Si(OH)4 coprecipitate obtained was oven dried at 393 K for 16 h and calcined at 773 K for 6 h in an open air furnace. 

The supported Ni catalysts (Ni content in % w/w) were prepared by the precipitation technique (7). The supports (United Catalysis India Ltd., India) were calcined at 773 K for 4 h prior to use. Ammonium carbonate (Loba Chemie, India) was used for precipitating Ni from Ni(N03)2.6H20 (S.D. Fine, India). The catalysts were calcined in a static air furnace at 773 K for 10 h and reduced in an activation furnace using silica-quartz tube at 773 K in H2 flow of 50 cm /min for 10 h. The reduced catalysts were passivated under N2 flow of 30 cmVmin for 2 h. 

The ASTM fire test procedure describes a laboratory determination of the flash ignition temperature (FIT) and spontaneous ignition temperature, or self-ignition temperature (SIT) of plastics and composites using a hot-air furnace. FIT is the minimum temperature at which sufficient flammable gases are emitted to ignite by a... 

The drying unit for this dryer is a basement hot air furnace as shown in the illustration. ... 

Hot Air Furnace - A heating unit where heat is distributed by means of convection or fans. 

ISO 871 [1IJ details a determination of ignition temperature using a hot-air furnace. This test determines the temperature at which plastics begin to decompose to flammable gaseous products. The original (1968) version of this test has recently been replaced by a version of the Setchkin test described immediately below. 

ISO 871 (1996), Plastics—Determination of ignition temperature using a hot air furnace. 

Figure 2.35 Dip-coating with water-based coatings, followed by drying in a hot-air furnace [237, HUT, 2003]...

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