Diversification is the keynote of the use of copper
and copper alloys in current general engineering practice. With such
a wide range of materials available in a variety of forms, such as
sheet, strip, wire, extruded sections, etc., engineering designers
are continuing to specify the copper and copper alloys for applications
large and small. A number of uses of copper today are spectacular
and impressive, such as the large copper brewing vats, but the majority
are in the form of machine or plant components and are usually unobtrusive
to the layman.
The vast chemical engineering industry, which affects almost every
aspect of daily life, uses copper (or its alloys) as a constructional
material because of its high rate of heat transfer, its ease of manipulation
and joining and its resistance to certain corrosive acids at normal
or moderately high temperatures. The choice of material often depends
mainly upon the latter consideration which in turn involves not only
the nature of the liquid concerned but also its temperature, concentration,
rate of flow, etc. For very exacting conditions 'Monel', a nickel-copper
alloy, is often specified.
Copper plate or sheet is ductile and malleable. It can readily be
hammered into pans or shaped and riveted, brazed, or welded into tanks,
boilers and other containers of all shapes and sizes. Very large thick
boiling-pans are also made from aluminum brass. Copper and a wide
range of alloys are fabricated into tubes for transporting a variety
of liquids and gases, including oil products, and they are also used
for heating coils and in evaporators, refrigerators (for which there
is a special range of sizes), in shell and tube condensers and for
numerous other purposes.
Copper evaporators are used for concentrating sugar, milk, extract
of malt, coffee, tannin, and for gelatine, lactic acid, sulphite liquor,
etc. The American nuclear power station at Indian Point has a giant
evaporator, 19.5 m (65 ft) long, in which the tube bundles are made
of 80/20 cupro-nickel.
Other copper alloys, including silicon bronze and nickel-copper 'Monel',
are employed in the evaporation of sea-water, an application which
is expected to increase with current expansion in the construction
of distillation plant.
Glucose converters, sugar rollers, stirrers, and furnace-pans, vacuum
pans, stills, fruit-slicing wheels, cattle-food and poultry mashers,
heat exchangers, textile-drying machines, and the rotproofing of textiles
for damp tropical climates are among the many miscellaneous items
for which copper and copper alloys are used.
Copper distilling columns used in the production of industrial alcohol,
fatty acids, essential oils, etc., are of special interest. The great
penicillin plant at Speke, near Liverpool, is a specific instance
of the use of copper in this respect. The recovery of extracts calls
for fractionating columns which are 6.9 m (23 ft) high and 1.5 m (5
ft) in diameter and are built of deoxidized copper sheets. Each column
is in seven sections, six of which have riveted copper bubble plates,
and each plate incorporates sixty copper bubblers and uptubes. This
makes an interesting comparison with the practice a thousand years
ago of the Arabs who distilled essences in gourd-shaped copper vessels.
In the numerous operations involved in the brewing of beer, copper
has played a predominant part for many centuries. Copper sheet is
very often used for lining the mash tuns and fermenting vessels; and
the brewing coppers are almost always made of copper, as indeed their
name implies. The world-famous brewery of Guinness's in Dublin has
nineteen of these huge coppers, each of which holds 88,920 liters
(23,400 gallons). The slotted false bottoms of brewery mash tuns are
made of bronze or brass. The round or oval coiled tubes called attemperators,
through which cold water or brine circulates in the fermenting vessels,
are of copper because of its high heat conductivity, and so are the
steam coils in the brewing copper and the various distribution pipes.
Copper tanks may even carry the beer away.
In the allied industry dealing with the distilling of whisky and other
alcoholic spirits, the initial operations somewhat resemble those
for brewing, but more alcohol is produced and a different yeast is
employed. The fermented liquor is distilled in either a fire- or steam-heated
whisky-still or in a columnar rectifying still. All this plant is
invariably made of copper, as are the tubular condensing coils.
In scores of other industries, which are loosely classified under
general engineering, copper and copper alloys are used for an infinite
variety of applications, ranging from small mass-produced parts in
free-machining brass to equipment for the 'space-age' industries of
rocket production and atomic energy. The giant electromagnets employed
in atom-smashers have copper wire windings. A cyclotron at Harwell
has 63 tonnes (70 tons) of copper strip for this purpose, while 'Nimrod',
a more recent machine at the same plant, has more than 270 tonnes
(300 tons) of high-conductivity copper bars coiled around its electromagnet.
The proton synchrotron at Brookhaven, New York, which is even larger,
can accelerate its bombarding particles up to 30,000 million electron-volts.
The electromagnet of this huge machine measures 253 m (843 ft) across
and contains about 3,600 tonnes (4,000 tons) of iron and 360 tonnes
(400 tons) of copper bars in coils. All these giants have evolved
from a small machine built in 1930, One of its most essential parts,
the magnetron body, was turned wholly out of high-conductivity copper.
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