Due to its excellent overall properties, copper is used extensively.
1. Air Conditioners and Refrigerators
The temperature control function of air conditioners and refrigerators is primarily achieved through the evaporation and condensation of the copper tubes in the heat exchanger. The size and heat transfer performance of the heat exchanger tubes largely determine the efficiency and miniaturization of the entire air conditioner and refrigeration system.
These machines utilize special-shaped copper tubes with high thermal conductivity. Leveraging copper's excellent processing properties, we have recently developed and produced heat exchangers with internal grooves and high fins. These heat exchangers are used in air conditioners, refrigerators, chemical plants, and waste heat recovery equipment. These new heat exchangers have increased their overall thermal conductivity by 2-3 times that of conventional tubes and 1.2-1.3 times that of conventional low-fin tubes. Already in use domestically, they can save 40% of copper and reduce the size of heat exchangers by more than one-third.
2. Clocks and Watches
Most of the working parts of clocks, timers, and clockwork devices currently in production are made of "clockwork brass." This alloy contains 1.5-2% lead, which offers excellent workability and is suitable for mass production. For example, gears are cut from long extruded brass bars, flat wheels are punched from strip of corresponding thickness, and brass or other copper alloys are used to create engraved clock faces, screws, and joints.
Many inexpensive watches are made of gunmetal (tin-zinc bronze) or plated with nickel silver (nickel silver). Some famous clocks are made of steel and copper alloys. The hour hand of Big Ben in the UK uses a solid gunmetal rod, while the minute hand is made of a 14-foot-long copper tube.
A modern clock factory, using copper alloy as the primary material, presses, and precise molds, can produce 10,000 to 30,000 clocks per day at a very low cost.
3. Papermaking
In today's rapidly changing information society, paper consumption is high. Papermaking may appear simple on the surface, but the papermaking process is complex, requiring numerous steps and the use of numerous machines, including coolers, evaporators, beaters, and papermaking machines. Many of these components, such as various heat exchange tubes, rollers, beater bars, semi-liquid pumps, and wire mesh, are mostly made of copper alloys.
For example, the current Fourdrinier papermaking machine sprays the prepared pulp onto a rapidly moving mesh with fine openings (40-60 mesh). The mesh is woven from brass and phosphor bronze wires and is very wide, typically over 20 feet (6 meters), and must remain perfectly straight.
The mesh moves over a series of small brass or copper rollers, carrying the sprayed pulp through it while absorbing moisture from below. The mesh simultaneously vibrates, bonding the fine fibers in the pulp. The mesh used in large papermaking machines can be as large as 26 feet 8 inches (8.1 meters) wide and 100 feet (30.5 meters) long. Wet paper pulp not only contains water but also contains chemicals used in the papermaking process, making it highly corrosive. To ensure paper quality, the screen material requires stringent requirements: high strength and elasticity, as well as resistance to pulp corrosion. Copper alloys are highly suitable for this purpose.
4. Printing
Printing involves photographic platemaking using copperplates. After the polished copperplate is sensitized with photosensitive emulsion, an image is photographed onto it. The exposed copperplate is heated to harden the emulsion. To prevent softening due to heat, copper often contains a small amount of silver or arsenic to raise its softening temperature. The plate is then etched to create a printing surface with a pattern of concave and convex dots.
On automatic typesetters, the typeface is created by arranging brass type blocks, another important use of copper in printing. Type blocks are typically made of leaded brass, but copper or bronze are also sometimes used.
5. Brewing
Copper plays a vital role in beer brewing worldwide. Copper is often used to line malt barrels and fermentation tanks. Some renowned breweries have over a dozen of these vats, each with a capacity exceeding 20,000 gallons. Steel pipes are often used to cool the fermentation vats. They are also used to pass steam through them for heating during brewing and for transporting the beer.
Steel stills are commonly used for distilling whiskey and other spirits. Whiskey and malt liquor are distilled twice, requiring two large copper stills.
6. Pharmaceuticals
In the pharmaceutical industry, various steaming, boiling, and vacuum equipment are made of pure copper. Nickel silver is widely used in medical devices. Copper alloys are also a common material for eyeglass frames, among other applications.
