Car-bottom

Car-bottom furnaces differ from standard types in that the charge is placed upon movable cars for running into the furnace enclosure. The top oi the car is refractory-lined and forms the furnace hearth. The top only is exposed to heat, the lower metal structure being pro-tec ted by the hearth brick, sand, and water seals at the sides and ends and by the circulation of cooling air around the car structure below the hearth. For use where floor space is hmited elevator furnaces serve similar purposes. 

Side-fired box and car-bottom furnaces are ideally fired with main burners on 2.5-ft to 4.5-ft (0.6 m to 1.4 m) centers along the top on one side, and small pumping high-velocity burners on the opposite bottom side. (See fig. 6.1.) The main burners should have ATP technology so that the temperature can be controlled to a flat profile with the T-sensors located at the level of the top of the load through each of the two long sidewalls. 

A natural-gas-fired car-bottom furnace is to be built for heating 175 000 pounds of steel ingots from 50 F to 2150 F in 16 hr. Using formulas and data from this book and References 51 and 52 as well as from refractory suppliers data, select hearth, sidewall, and roof construction. Then calculate heat loss, heat storage, and coldface temperatures for the selected hearth, wall, and roof. 

Track hoppers are needed for some boxcar and bottom-dump-car shipments. Since boxcars discharge to one side, fairly light construction can be used for the hoppers, which are located to one side of the tracks. However, for bottom-dump cars, the hoppers must be located on the centerline of the tracks. This requires heavy track girders over a hopper and feeder conveyor pit, but hopper depth must be set to give sufficient angle for material to flow well. Belts or reciprocating-plate feeders commonly carry the material to the bucket elevator. 

What do we do when there are other ways of doing free work As an example, if our car were initially moving downhill with velocity v but ended up stationary at the bottom of the hill, we would have... 

Thermal insulation can be used to maintain lower temperatures in the containers and to provide improved protection from fire. Tank cars, trailers, and other containers can be specified without bottom outlets or be provided with skid-protection for bottom outlets. 

Approach of borohydride to the top face of the carbonyl group is sterically hindered by one of the methyl groups. The bottom face of the car bonyl group is less congested, and the major product is formed by hydride transfer from this direction. 

This drive can be used for a wide range of car sizes but has a limit to the speed of travel of approximately 2.5 m/s. The elevator machine room is usually located above the elevator shaft. However, bottom-of-shaft machine rooms are not unknown, although they tend to be more costly. 

Rail tank cars have bottom outlets terminating in a quick-acting coupling, and are designed for pump off-loading only. A flow indicator should be inserted between the terminal outlet and the fill line. Flexible connections for steam and oil lines should be provided for the maximum number of cars that will be discharged simultaneously. 

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