1.
Ballcock
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A ballcock is a mechanism or machine for filling water tanks, such as those found in flush toilets, while avoiding overflow and backflow. The modern ballcock was invented by José Antonio de Alzate y Ramírez, a Mexican priest and scientist and it consists of a valve connected to a hollow sealed float by means of a lever, mounted near the top of the tank. The float is often ball-shaped, hence the name ballcock, the valve is connected to the incoming water supply, and is opened and closed by the lever which has the float mounted on the end. When the water rises, the float rises with it, once it rises to a pre-set level. This is an example of feedback and of proportional control. When a toilets handle is turned, a mechanism is activated by means of a rod or chain. The mechanism may be a valve, which is designed to sink more slowly than the water. As the tank water level drops, the float descends and actuates the fill valve, water is fed to the tank to replenish its supply, and a smaller flow is directed into the overflow tube to refill the bowl. Once the flapper valve closes, the flow from the fill valve continues until the tank level again reaches the fill line. Another discharge mechanism, common in the United Kingdom, is a siphon, the rod or chain lifts a piston that pulls an initial charge of water up into the siphon. When the column of water passes over the bend and starts to fall down the exit pipe. Toward the end of the process, the ballcock responds to the drop in water level. Should the float or valve fail and allow the level to exceed the fill line. Although this does not stop the wastage of water, it avoids the flooding that would occur after a single-point valve failure. These devices are sold at most hardware, plumbing supply, introduction to ballcock valves US2837111, Mueller, Paul G. Ball cock valve mechanism, published 6 January 1955, issued 3 June 1958, hysterisis issue. Such flush tank valves as now used are closed against the pressure of water from a source of supply which pressure opposes the movement of the float under rising water level in the tank. US418162, Cahill, W. J. Ball cock, published 2 October 1889, issued 31 December 1889, hysterisis issue
2.
Valve
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A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically fittings, but are discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure, the word is derived from the Latin valva, the moving part of a door, in turn from volvere, to turn, roll. The simplest, and very ancient, valve is simply a freely hinged flap which drops to obstruct fluid flow in one direction and this is called a check valve, as it prevents or checks the flow in one direction. Modern control valves may regulate pressure or flow downstream and operate on sophisticated automation systems, even aerosols have a tiny valve built in. Valves are also used in the military and transport sectors, valves may be operated manually, either by a handle, lever, pedal or wheel. Valves may also be automatic, driven by changes in pressure, temperature and these changes may act upon a diaphragm or a piston which in turn activates the valve, examples of this type of valve found commonly are safety valves fitted to hot water systems or boilers. More complex control systems using valves requiring automatic control based on an external input require an actuator, an actuator will stroke the valve depending on its input and set-up, allowing the valve to be positioned accurately, and allowing control over a variety of requirements. Valves vary widely in form and application, sizes typically range from 0.1 mm to 60 cm. Special valves can have a diameter exceeding 5 meters, valve costs range from simple inexpensive disposable valves to specialized valves which cost thousands of US dollars per inch of the diameter of the valve. Disposable valves may be found in household items including mini-pump dispensers. Valves are quite diverse and may be classified into a number of basic types, valves may also be classified by how they are actuated, Hydraulic Pneumatic Manual Solenoid valve Motor The main parts of the most usual type of valve are the body and the bonnet. These two parts form the casing that holds the fluid going through the valve, the valves body is the outer casing of most or all of the valve that contains the internal parts or trim. The bonnet is the part of the encasing through which the stem passes, the bonnet typically screws into or is bolted to the valve body. Valve bodies are usually metallic or plastic, brass, bronze, gunmetal, cast iron, steel, alloy steels and stainless steels are very common. Seawater applications, like plants, often use duplex valves, as well as super duplex valves, due to their corrosion resistant properties. Alloy 20 valves are used in sulphuric acid plants, whilst monel valves are used in hydrofluoric acid plants. Hastelloy valves are used in high temperature applications, such as nuclear plants
3.
Gate valve
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A gate valve, also known as a sluice valve, is a valve which opens by lifting a round or rectangular gate/wedge out of the path of the fluid. The gate faces can be parallel, but are most commonly wedge-shaped, gate valves are primarily used to permit or prevent the flow of liquids, but typical gate valves shouldnt be used for regulating flow, unless they are specifically designed for that purpose. Because of their ability to cut through liquids, gate valves are used in the petroleum industry. For extremely thick fluids, a specialty valve often known as a gate valve is used to cut through the liquid. On opening the valve, the flow path is enlarged in a highly nonlinear manner with respect to percent of opening. This means that flow rate does not change evenly with stem travel, also, a partially open gate tends to vibrate from the fluid flow. Most of the change occurs near shutoff with a relatively high fluid velocity causing gate and seat wear. Typical gate valves are designed to be opened or closed. When fully open, the gate valve has no obstruction in the flow path. Gate valves are actuated by a stem which connects the actuator to the gate. They are characterised as having either a rising or a nonrising stem, rising stems are fixed to the gate and rise and lower together as the valve is operated, providing a visual indication of valve position. The actuator takes the form of a nut which is rotated around the stem to move it. Nonrising stem valves are fixed to, and rotate with, the actuator and they may have a pointer threaded onto the upper end of the stem to indicate valve position, since the gates motion is concealed inside the valve. Nonrising stems are used underground or where space is limited. Bonnets provide leakproof closure for the valve body, gate valves may have a screw-in, union, or bolted bonnet. Screw-in bonnet is the simplest, offering a durable, pressure-tight seal, union bonnet is suitable for applications requiring frequent inspection and cleaning. It also gives the added strength. Bolted bonnet is used for larger valves and higher pressure applications, another type of bonnet construction in a gate valve is pressure seal bonnet
4.
Globe valve
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A globe valve, different from ball valve, is a type of valve used for regulating flow in a pipeline, consisting of a movable disk-type element and a stationary ring seat in a generally spherical body. Globe valves are named for their body shape with the two halves of the body being separated by an internal baffle. This has an opening that forms a seat onto which a plug can be screwed in to close the valve. The plug is called a disc or disk. In globe valves, the plug is connected to a stem which is operated by screw action using a handwheel in manual valves, typically, automated globe valves use smooth stems rather than threaded and are opened and closed by an actuator assembly. Although globe valves in the past had the bodies which gave them their name. However, the term globe valve is often used for valves that have such an internal mechanism. It contains all of the internal parts that will come in contact with the substance being controlled by the valve. The bonnet is connected to the body and provides the containment of the fluid, gas, globe valves are typically two-port valves, although three port valves are also produced mostly in straight-flow configuration. Ports are openings in the body for fluid flowing in or out, the two ports may be oriented straight across from each other or anywhere on the body, or oriented at an angle. Globe valves with ports at such an angle are called angle globe valves, globe valves are mainly used for corrosive or high viscous fluids which solidify at room temperature. This is because straight valves are designed so that the pipe is in line with the inlet pipe. In the case of angle valves, the pipe is directed towards the bottom. This allows the fluid to drain off, in turn, this prevents clogging and/or corrosion of the valve components over a period of time. A globe valve can also have a body in the shape of a Y and this will allow the construction of the valve to be straight at the bottom as opposed to the conventional pot type construction in case of other valves. This will again allow the fluid to pass through without difficulty, the bonnet provides a leakproof closure for the valve body. The threaded section of the stem goes through a hole with matching threads in the bonnet, globe valves may have a screw-in, union, or bolted bonnet. Screw-in bonnet is the simplest bonnet, offering a durable, pressure-tight seal, union bonnet is suitable for applications requiring frequent inspection or cleaning
5.
Pressure
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Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure is the relative to the ambient pressure. Various units are used to express pressure, Pressure may also be expressed in terms of standard atmospheric pressure, the atmosphere is equal to this pressure and the torr is defined as 1⁄760 of this. Manometric units such as the centimetre of water, millimetre of mercury, Pressure is the amount of force acting per unit area. The symbol for it is p or P, the IUPAC recommendation for pressure is a lower-case p. However, upper-case P is widely used. The usage of P vs p depends upon the field in one is working, on the nearby presence of other symbols for quantities such as power and momentum. Mathematically, p = F A where, p is the pressure, F is the normal force and it relates the vector surface element with the normal force acting on it. It is incorrect to say the pressure is directed in such or such direction, the pressure, as a scalar, has no direction. The force given by the relationship to the quantity has a direction. If we change the orientation of the element, the direction of the normal force changes accordingly. Pressure is distributed to solid boundaries or across arbitrary sections of normal to these boundaries or sections at every point. It is a parameter in thermodynamics, and it is conjugate to volume. The SI unit for pressure is the pascal, equal to one newton per square metre and this name for the unit was added in 1971, before that, pressure in SI was expressed simply in newtons per square metre. Other units of pressure, such as pounds per square inch, the CGS unit of pressure is the barye, equal to 1 dyn·cm−2 or 0.1 Pa. Pressure is sometimes expressed in grams-force or kilograms-force per square centimetre, but using the names kilogram, gram, kilogram-force, or gram-force as units of force is expressly forbidden in SI. The technical atmosphere is 1 kgf/cm2, since a system under pressure has potential to perform work on its surroundings, pressure is a measure of potential energy stored per unit volume. It is therefore related to density and may be expressed in units such as joules per cubic metre. Similar pressures are given in kilopascals in most other fields, where the prefix is rarely used
6.
Bar (unit)
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The bar is a metric unit of pressure, but is not approved as part of the International System of Units. It is defined as equal to 100000 Pa, which is slightly less than the current average atmospheric pressure on Earth at sea level. The bar and the millibar were introduced by the Norwegian meteorologist Vilhelm Bjerknes, use of the bar is deprecated by some professional bodies in some fields. The International Astronomical Union also lists it under Non-SI units and symbols whose continued use is deprecated, as of 2004, the bar is legally recognized in countries of the European Union. Units derived from the bar include the megabar, kilobar, decibar, centibar, the notation bar, though deprecated by various bodies, represents gauge pressure, i. e. pressure in bars above ambient or atmospheric pressure. The bar is defined using the SI derived unit, pascal,1 bar ≡100000 Pa. Thus,1 bar is equal to,100 kPa 1×105 N/m21000000 Ba, notes,1 millibar =1 one-thousandth bar, or 1×10−3 bar 1 millibar =1 hectopascal. The word bar has its origin in the Greek word βάρος, the units official symbol is bar, the earlier symbol b is now deprecated and conflicts with the use of b denoting the unit barn, but it is still encountered, especially as mb to denote the millibar. Between 1793 and 1795, the bar was used for a unit of weight in an early version of the metric system. Atmospheric air pressure is given in millibars where standard sea level pressure is defined as 1013 mbar,101.3,1.013 bar. Despite the millibar not being an SI unit, meteorologists and weather reporters worldwide have long measured air pressure in millibars as the values are convenient, for example, the weather office of Environment Canada uses kilopascals and hectopascals on their weather maps. In contrast, Americans are familiar with the use of the millibar in US reports of hurricanes, in fresh water, there is an approximate numerical equivalence between the change in pressure in decibars and the change in depth from the water surface in metres. Specifically, an increase of 1 decibar occurs for every 1.019716 m increase in depth, in sea water with respect to the gravity variation, the latitude and the geopotential anomaly the pressure can be converted into meters depth according to an empirical formula. As a result, decibars are commonly used in oceanography, many engineers worldwide use the bar as a unit of pressure because, in much of their work, using pascals would involve using very large numbers. In the automotive field, turbocharger boost is often described in bars outside the USA), unicode has characters for mb and bar, but they exist only for compatibility with legacy Asian encodings and are not intended to be used in new documents. The kilobar, equivalent to 100 MPa, is used in geological systems. Bar and bara are sometimes used to indicate absolute pressures and bar and this usage is deprecated and fuller descriptions such as gauge pressure of 2 bar or 2 bar gauge are recommended.0 Unported License but not under the GFDL. Non-SI units accepted for use with the SI
7.
Temperature
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A temperature is an objective comparative measurement of hot or cold. It is measured by a thermometer, several scales and units exist for measuring temperature, the most common being Celsius, Fahrenheit, and, especially in science, Kelvin. Absolute zero is denoted as 0 K on the Kelvin scale, −273.15 °C on the Celsius scale, the kinetic theory offers a valuable but limited account of the behavior of the materials of macroscopic bodies, especially of fluids. Temperature is important in all fields of science including physics, geology, chemistry, atmospheric sciences, medicine. The Celsius scale is used for temperature measurements in most of the world. Because of the 100 degree interval, it is called a centigrade scale.15, the United States commonly uses the Fahrenheit scale, on which water freezes at 32°F and boils at 212°F at sea-level atmospheric pressure. Many scientific measurements use the Kelvin temperature scale, named in honor of the Scottish physicist who first defined it and it is a thermodynamic or absolute temperature scale. Its zero point, 0K, is defined to coincide with the coldest physically-possible temperature and its degrees are defined through thermodynamics. The temperature of zero occurs at 0K = −273. 15°C. For historical reasons, the triple point temperature of water is fixed at 273.16 units of the measurement increment, Temperature is one of the principal quantities in the study of thermodynamics. There is a variety of kinds of temperature scale and it may be convenient to classify them as empirically and theoretically based. Empirical temperature scales are historically older, while theoretically based scales arose in the middle of the nineteenth century, empirically based temperature scales rely directly on measurements of simple physical properties of materials. For example, the length of a column of mercury, confined in a capillary tube, is dependent largely on temperature. Such scales are only within convenient ranges of temperature. For example, above the point of mercury, a mercury-in-glass thermometer is impracticable. A material is of no use as a thermometer near one of its phase-change temperatures, in spite of these restrictions, most generally used practical thermometers are of the empirically based kind. Especially, it was used for calorimetry, which contributed greatly to the discovery of thermodynamics, nevertheless, empirical thermometry has serious drawbacks when judged as a basis for theoretical physics. Theoretically based temperature scales are based directly on theoretical arguments, especially those of thermodynamics, kinetic theory and they rely on theoretical properties of idealized devices and materials
8.
Metal
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A metal is a material that is typically hard, opaque, shiny, and has good electrical and thermal conductivity. Metals are generally malleable—that is, they can be hammered or pressed permanently out of shape without breaking or cracking—as well as fusible and ductile, about 91 of the 118 elements in the periodic table are metals, the others are nonmetals or metalloids. Some elements appear in both metallic and non-metallic forms, astrophysicists use the term metal to collectively describe all elements other than hydrogen and helium, the simplest two, in a star. The star fuses smaller atoms, mostly hydrogen and helium, to larger ones over its lifetime. In that sense, the metallicity of an object is the proportion of its matter made up of all chemical elements. Many elements and compounds that are not normally classified as metals become metallic under high pressures, the atoms of metallic substances are typically arranged in one of three common crystal structures, namely body-centered cubic, face-centered cubic, and hexagonal close-packed. In bcc, each atom is positioned at the center of a cube of eight others, in fcc and hcp, each atom is surrounded by twelve others, but the stacking of the layers differs. Some metals adopt different structures depending on the temperature, atoms of metals readily lose their outer shell electrons, resulting in a free flowing cloud of electrons within their otherwise solid arrangement. This provides the ability of metallic substances to easily transmit heat, while this flow of electrons occurs, the solid characteristic of the metal is produced by electrostatic interactions between each atom and the electron cloud. This type of bond is called a metallic bond, Metals are usually inclined to form cations through electron loss, reacting with oxygen in the air to form oxides over various timescales. Examples,4 Na + O2 →2 Na2O2 Ca + O2 →2 CaO4 Al +3 O2 →2 Al2O3, the transition metals are slower to oxidize because they form a passivating layer of oxide that protects the interior. Others, like palladium, platinum and gold, do not react with the atmosphere at all, some metals form a barrier layer of oxide on their surface which cannot be penetrated by further oxygen molecules and thus retain their shiny appearance and good conductivity for many decades. The oxides of metals are generally basic, as opposed to those of nonmetals, exceptions are largely oxides with very high oxidation states such as CrO3, Mn2O7, and OsO4, which have strictly acidic reactions. Painting, anodizing or plating metals are good ways to prevent their corrosion, however, a more reactive metal in the electrochemical series must be chosen for coating, especially when chipping of the coating is expected. Water and the two form an electrochemical cell, and if the coating is less reactive than the coatee. Metals in general have high conductivity, high thermal conductivity. Typically they are malleable and ductile, deforming under stress without cleaving, in terms of optical properties, metals are shiny and lustrous. Sheets of metal beyond a few micrometres in thickness appear opaque, although most metals have higher densities than most nonmetals, there is wide variation in their densities, lithium being the least dense solid element and osmium the densest
9.
Plastic
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Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and can be molded into solid objects. Plastics are typically organic polymers of high mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood, stone, horn and bone, leather, paper, metal, glass, and ceramic, in most of their former uses. In developed countries, about a third of plastic is used in packaging, other uses include automobiles, furniture, and toys. In the developing world, the ratios may be different - for example, the worlds first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term plastics. Toward the end of the century, one approach to this problem was met with wide efforts toward recycling, the word plastic is derived from the Greek πλαστικός meaning capable of being shaped or molded, from πλαστός meaning molded. The common word plastic should not be confused with the technical adjective plastic, used for insulating parts in electrical fixtures, paper laminated products, thermally insulation foams. Problems include the probability of moldings naturally being dark colors, One of the most expensive commercial polymers. It forms the basis of artistic and commercial acrylic paints when suspended in water with the use of other agents, polytetrafluoroethylene – Heat-resistant, low-friction coatings, used in things like non-stick surfaces for frying pans, plumbers tape and water slides. It is more known as Teflon. Urea-formaldehyde – One of the aminoplasts and used as an alternative to phenolics. Used as an adhesive and electrical switch housings. Early plastics were bio-derived materials such as egg and blood proteins, in 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines. Treated cattle horns were used as windows for lanterns in the Middle Ages, materials that mimicked the properties of horns were developed by treating milk-proteins with lye. In the 1800s, as industrial chemistry developed during the Industrial Revolution, the development of plastics also accelerated with Charles Goodyears discovery of vulcanization to thermoset materials derived from natural rubber. Parkesine is considered the first man-made plastic, the plastic material was patented by Alexander Parkes, In Birmingham, UK in 1856. It was unveiled at the 1862 Great International Exhibition in London, parkesine won a bronze medal at the 1862 Worlds fair in London
10.
Ceramic
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A ceramic is an inorganic, non-metallic, solid material comprising metal, non-metal or metalloid atoms primarily held in ionic and covalent bonds. This article gives an overview of ceramic materials from the point of view of materials science, the crystallinity of ceramic materials ranges from highly oriented to semi-crystalline, vitrified, and often completely amorphous. Most often, fired ceramics are either vitrified or semi-vitrified as is the case with earthenware, stoneware, varying crystallinity and electron consumption in the ionic and covalent bonds cause most ceramic materials to be good thermal and electrical insulators. With such a range of possible options for the composition/structure of a ceramic, the breadth of the subject is vast. Many composites, such as fiberglass and carbon fiber, while containing ceramic materials, are not considered to be part of the ceramic family. The earliest ceramics made by humans were pottery objects or figurines made from clay, either by itself or mixed with materials like silica, hardened, sintered. Later ceramics were glazed and fired to create smooth, colored surfaces, decreasing porosity through the use of glassy, ceramics now include domestic, industrial and building products, as well as a wide range of ceramic art. In the 20th century, new materials were developed for use in advanced ceramic engineering. The word ceramic comes from the Greek word κεραμικός, of pottery or for pottery, from κέραμος, potters clay, tile, the earliest known mention of the root ceram- is the Mycenaean Greek ke-ra-me-we, workers of ceramics, written in Linear B syllabic script. The word ceramic may be used as an adjective to describe a material, product or process, or it may be used as a noun, either singular, or, more commonly, as the plural noun ceramics. A ceramic material is an inorganic, non-metallic, often crystalline oxide, nitride or carbide material, some elements, such as carbon or silicon, may be considered ceramics. Ceramic materials are brittle, hard, strong in compression, weak in shearing and they withstand chemical erosion that occurs in other materials subjected to acidic or caustic environments. Ceramics generally can withstand high temperatures, such as temperatures that range from 1,000 °C to 1,600 °C. Glass is often not considered a ceramic because of its amorphous character. However, glassmaking involves several steps of the process and its mechanical properties are similar to ceramic materials. Traditional ceramic raw materials include minerals such as kaolinite, whereas more recent materials include aluminium oxide. The modern ceramic materials, which are classified as advanced ceramics, include silicon carbide, both are valued for their abrasion resistance, and hence find use in applications such as the wear plates of crushing equipment in mining operations. Advanced ceramics are used in the medicine, electrical, electronics industries. Crystalline ceramic materials are not amenable to a range of processing
