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Glassmaking
Glass production involves two main methods – the float glass process that produces sheet glass, and glassblowing that produces bottles and other containers. It has been done in a variety of ways during the history of glass. Glass container production Broadly, modern glass container factories are three-part operations: the "batch house", the "hot end", and the "cold end". The batch house handles the raw materials; the hot end handles the manufacture proper—the forehearth, forming machines, and annealing ovens; and the cold end handles the product-inspection and packaging equipment. Batch processing system (batch house) Batch processing is one of the initial steps of the glass-making process. The batch house simply houses the raw materials in large silos (fed by truck or railcar), and holds anywhere from 1–5 days of material. Some batch systems include material processing such as raw material screening/sieve, drying, or pre-heating (i.e. cullet). Whether automated or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Glass
The history of glass-making dates back to at least 3,600 years ago in Mesopotamia. However, most writers claim that they may have been producing copies of glass objects from Egypt. Other archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or Egypt. The earliest known glass objects, of the mid 2,000 BCE, were beads, perhaps initially created as the accidental by-products of metal-working (slags) or during the production of faience, a pre-glass vitreous material made by a process similar to glazing. Glass products remained a luxury until the disasters that overtook the late Bronze Age civilizations seemingly brought glass-making to a halt. Development of glass technology in India may have begun in 1,730 BCE. From across the former Roman Empire, archaeologists have recovered glass objects that were used in domestic, industrial and funerary contexts. Anglo-Saxon glass has been found across England during archaeological excava ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass
Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window panes, tableware, and optics. Some common objects made of glass are named after the material, e.g., a Tumbler (glass), "glass" for drinking, "glasses" for vision correction, and a "magnifying glass". Glass is most often formed by rapid cooling (quenching) of the Melting, molten form. Some glasses such as volcanic glass are naturally occurring, and obsidian has been used to make arrowheads and knives since the Stone Age. Archaeological evidence suggests glassmaking dates back to at least 3600 BC in Mesopotamia, Ancient Egypt, Egypt, or Syria. The earliest known glass objects were beads, perhaps created accidentally during metalworking or the production of faience, which is a form of pottery using lead glazes. Due to its ease of formability int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glassblowing
Glassblowing is a glassforming technique that involves inflating molten glass into a bubble (or parison) with the aid of a blowpipe (or blow tube). A person who blows glass is called a ''glassblower'', ''glassmith'', or ''gaffer''. A '' lampworker'' (often also called a glassblower or glassworker) manipulates glass with the use of a torch on a smaller scale, such as in producing precision laboratory glassware out of borosilicate glass. Technology Principles As a novel glass forming technique created in the middle of the 1st century BC, glassblowing exploited a working property of glass that was previously unknown to glassworkers; inflation, which is the expansion of a molten blob of glass by introducing a small amount of air into it. That is based on the liquid structure of glass where the atoms are held together by strong chemical bonds in a disordered and random network,Frank, S 1982. Glass and Archaeology. Academic Press: London. Freestone, I. (1991). "Looking into Glass". ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dealkalization
Dealkalization is a process of surface modification applicable to glasses containing alkali ions, wherein a thin surface layer is created that has a lower concentration of alkali ions than is present in the underlying, bulk glass. This change in surface composition commonly alters the observed properties of the surface, most notably enhancing corrosion resistance. Many commercial glass products such as containers are made of soda-lime glass, and therefore have a substantial percentage of sodium ions in their internal structure. Since sodium is an alkali element, its selective removal from the surface results in a dealkalized surface. A classic example of dealkalization is the treatment of glass containers, where a special process is used to create a dealkalized inside surface that is more resistant to interactions with liquid products put inside the container. However, the term dealkalization may also be generally applied to any process where a glass surface forms a thin surfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Float Glass
Float glass is a sheet of glass made by floating molten glass on a bed of molten metal of a low melting point, typically tin, although lead was used for the process in the past. This method gives the sheet uniform thickness and a very flat surface. The float glass process is also known as the Pilkington process, named after the British glass manufacturer Pilkington, which pioneered the technique in the 1950s at their production site in St Helens, Merseyside. Modern windows are usually made from float glass, though Corning Incorporated uses the overflow downdraw method. Most float glass is soda–lime glass, although relatively minor quantities of specialty borosilicate and flat panel display glass are also produced using the float glass process. History Until the 16th century, window glass or other flat glass was generally cut from large discs (or rondels) of crown glass. Larger sheets of glass were made by blowing large cylinders which were cut open and flattened, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annealing (glass)
Annealing is a process of slowly cooling hot glass objects after they have been formed, to relieve residual internal stresses introduced during manufacture. Especially for smaller, simpler objects, annealing may be incidental to the process of manufacture, but in larger or more complex products it commonly demands a special process of annealing in a temperature-controlled kiln known as a lehr. Annealing of glass is critical to its durability. Glass that has not been properly annealed retains thermal stresses caused by quenching, which will indefinitely decrease the strength and reliability of the product. Inadequately annealed glass is likely to crack or shatter when subjected to relatively small temperature changes or to mechanical shock or stress. It even may fail spontaneously. To anneal glass, it is necessary to heat it to its annealing temperature, at which its viscosity, η, drops to 1013 Poise (1013 dyne-second/cm2). For most kinds of glass, this annealing temperature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitreous Enamel
Vitreous enamel, also called porcelain enamel, is a material made by melting, fusing powdered glass to a substrate by firing, usually between . The powder melts, flows, and then hardens to a smooth, durable vitrification, vitreous coating. The word ''vitreous'' comes from the Latin , meaning "glassy". Enamel can be used on metal, enamelled glass, glass, overglaze decoration, ceramics, stone, or any material that will withstand the fusing temperature. In technical terms fired enamelware is an integrated layered composite of glass and another material (or more glass). The term "enamel" is most often restricted to work on metal, which is the subject of this article. Essentially the same technique used with other bases is known by different terms: on glass as ''enamelled glass'', or "painted glass", and on pottery it is called ''overglaze decoration'', "overglaze enamels" or "enamelling". The craft is called "enamelling", the artists "enamellers" and the objects produced can be cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screen-printing
Screen printing is a printing technique where a mesh is used to transfer ink (or dye) onto a Substrate (printing), substrate, except in areas made impermeable to the ink by a blocking stencil. A blade or squeegee is moved across the screen in a "flood stroke" to fill the open mesh apertures with ink, and a reverse stroke then causes the screen to touch the substrate momentarily along a line of contact. This causes the ink to wet the substrate and be pulled out of the mesh apertures as the screen springs back after the blade has passed. One colour is printed at a time, so several screens can be used to produce a multi-coloured image or design. Traditionally, silk was used in the process. Currently, synthetic threads are commonly used. The most popular mesh in general use is made of polyester. There are special-use mesh materials of nylon and stainless steel available to the screen-printer. There are also different types of mesh size which will determine the outcome and look o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractory
In materials science, a refractory (or refractory material) is a material that is resistant to decomposition by heat or chemical attack and that retains its strength and rigidity at high temperatures. They are inorganic, non-metallic compounds that may be porous or non-porous, and their crystallinity varies widely: they may be crystalline, polycrystalline, amorphous, or composite. They are typically composed of oxides, carbides or nitrides of the following elements: silicon, aluminium, magnesium, calcium, boron, chromium and zirconium. Many refractories are ceramics, but some such as graphite are not, and some ceramics such as clay pottery are not considered refractory. Refractories are distinguished from the '' refractory metals'', which are elemental metals and their alloys that have high melting temperatures. Refractories are defined by ASTM C71 as "non-metallic materials having those chemical and physical properties that make them applicable for structures, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waste Heat
Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utility (or in thermodynamics lexicon a lower exergy or higher entropy) than the original energy source. Sources of waste heat include all manner of human activities, natural systems, and all organisms, for example, incandescent light bulbs get hot, a refrigerator warms the room air, a building gets hot during peak hours, an internal combustion engine generates high-temperature exhaust gases, and electronic components get warm when in operation. Instead of being "wasted" by release into the ambient environment, sometimes waste heat (or cold) can be used by another process (such as using hot engine coolant to heat a vehicle), or a portion of heat that would otherwise be wasted can be reused in the same process if make-up heat is added to the sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emulsion
An emulsion is a mixture of two or more liquids that are normally Miscibility, immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms ''colloid'' and ''emulsion'' are sometimes used interchangeably, ''emulsion'' should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid (the dispersed phase (matter), phase) is dispersion (chemistry), dispersed in the other (the continuous phase). Examples of emulsions include vinaigrettes, homogenized milk, liquid biomolecular condensates, and some cutting fluids for metal working. Two liquids can form different types of emulsions. As an example, oil and water can form, first, an oil-in-water emulsion, in which the oil is the dispersed phase, and water is the continuous phase. Second, they can form a water-in-oil emulsion, in which water is the dispersed phase and oil is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bottles, cups, jars, etc.). , over 100 million tonnes of polyethylene resins are being produced annually, accounting for 34% of the total plastics market. Many kinds of polyethylene are known, with most having the chemical formula (C2H4)''n''. PE is usually a mixture of similar polymers of ethylene, with various values of ''n''. It can be ''low-density'' or ''high-density'' and many variations thereof. Its properties can be modified further by crosslinking or copolymerization. All forms are nontoxic as well as chemically resilient, contributing to polyethylene's popularity as a multi-use plastic. However, polyethylene's chemical resilience also makes it a long-lived and decomposition-resistant pollutant when disposed of improperly. Being a h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
