Barrel furnaces

Water-cooled supports inside the furnaces should be reduced to a minimum for good fuel economy and furnace productivity. The high operating temperatures on these furnaces necessitate alert maintenance. 

Butt-welding furnaces that use type E convex tile radiation burners instead of impingement are controlled by eye measurement of strip temperature. With impingement heating (type H burners), control is by observing the width of strip edge burning, a much more accurate way. 

Calculating furnace size and firing rate can be accomplished by the Shannon Method detailed in chapter 8. The required furnace length = required heating time multiplied by stock feed speed. Heating times and cooling times between barrels should be figured and plotted alternately. 

Examples of nonuniform heating-control problems above 10(X) F (538 C) are (1) nonuniform scale formation with carbon steels, (2) questionable completion of the combustion reaction (pic contact the load surface), (3) sticky scale with resultant rolled-in scale, (4) spotty decarburization of high carbon steels, (5) some stainless steels may not tolerate contact with the reducing atmosphere within the flames, and (6) using impingement heating for steel pieces of heavy cross section could cause formation of reflective scale with resultant reduction of heat transfer. 

---

Fig. 4.15. Barrel furnaces for impingement heating of skelp edges—for welding into seamed pipe or tube, left, side view of three barrels right, end view. Not shown, but necessary, are slag cleanout access doors in all sections.

Typical equipment made from tantalum includes heat exchangers, reaction vessels liners, thermowells, and heating elements or heat shields for high temperature vacuum sintering furnaces. Tantalum fabricated parts are found in the manufacturing of pharmaceuticals, explosives, insecticides, dyes, acidic baskets for silver cyanide barrel platers, and in hydrochloric and hydrobromic acid condensers. 

Purple permanganate ion, 15 597 Purple pigments, 7 349-350 for inks, 14 318 Pusher centrifuges, 11 392 Pusher furnaces, 12 289-290 Push-pull coupler device, 13 422 Push-pull rods/barrels, 24 59 Putrescine, 2 79... 

The ash is mixed with 5 to 10 per cent, of slaked lime and placed in wooden barrels with false bottoms. Hot water is poured over the mixture, and, after standing for some time, the liquid is drawn off from time to time by removing a plug near the bottom of the cask. The liquid with a sp. gr. over 1 -15 is evaporated the low sp. gr. liquor may be used for lixiviating more ash and the residue in the barrels may be used as manure. The evaporation of the densest liquor to dryness is conducted in cast-iron pots, and the residue is afterwards calcined in a reverberatory furnace to burn away the organic matter—at the same time sulphates may be converted into sulphides. The product is crude potash. The crude potash may be mixed with sawdust and re-calcined. It is then digested with twice its weight of hot water, filtered, and cooled. The less soluble impurities—mainly potassium sulphate—crystallize out, and finally the mother liquid is evaporated to dryness and calcined as before, - or the solu. may be evaporated until crystals of potassium carbonate are deposited. 

I have here a furnace with a pipe going through it like an iron gun-barrel, and I have stuffed that barrel full of bright iron-turnings, and placed it across the fire, to be made red-hot. We can either send air through the barrel to come in contact with the iron, or we can send steam from this little boiler at the end of the barrel. Here is a stop-cock which shuts off the steam from the barrel until we wish to admit it There is some water in these glass jars, which... 

Putting that solution aside, let us nowasee what effect this instrument will have upon water. Here are two little platinum - plates which I intend to make the ends of the battery, and this (c) is a little vessel so shaped as to enable me to take it to pieces, and shew you its construction. In these two cups (A. and B) I pour mercury, which touches the ends of the wires connected with the platinum-plates. In the vessel (c) I pour some water containing a little acid (but which is put only for the purpose of facilitating the action it undergoes no change in the process), and connected with the top of the vessel is a bent glass tube (d), which may remind you of the pipe which was connected with the gun barrel in our furnace... 

A late-fifteenth-century Selden who loved praying— very unusual for our family— built this room as a chapel, but his son had other ideas and knocked out the walls and ceilings to make a laboratory. There s plenty to distract me large and small furnaces, benches, shelves, barrels, vats, boxes, a globe, barometers, scales, a variety of bellows, and receptacles of every shape—retorts, cucurbits, cmcibles, and alembics. We use some of these things every day others are too rare and precious except for the most advanced stages of alchemy. 

There were great changes here. The shutters had been repaired and nailed into place, the furnace cleaned, and a fire laid. My father s workbench was in its old position, the top planed smooth and polished, his staff propped against it. Even more intriguing was that some form of experiment had been set up a long tube of metal from what looked like a gun barrel had been bent into an S shape, one end of which was connected to a retort, the other to an inverted flask. 

---