Laboratory flasks are vessels or containers that fall into the category of laboratory equipment known as glassware. In laboratory and other scientific settings, they are referred to as flasks. Flasks come in a number of shapes and a wide range of sizes, but a common distinguishing aspect in their shapes is a wider vessel "body" and one narrower tubular sections at the top called necks which have an opening at the top. Laboratory flask sizes are specified by the volume they can hold in metric units such as milliliters or liters. Laboratory flasks have traditionally been made of glass, but can be made of plastic. At the opening at top of the neck of some glass flasks such as round-bottom flasks, retorts, or sometimes volumetric flasks, there are outer tapered ground glass joints; some flasks volumetric flasks, come with a laboratory rubber stopper, bung, or cap for capping the opening at the top of the neck. Such stoppers can be made of plastic. Glass stoppers have a matching tapered inner ground glass joint surface, but only of stopper quality.
Flasks which do not come with such stoppers or caps included may be capped with a rubber bung or cork stopper. Flasks can be used for making solutions or for holding, collecting, or sometimes volumetrically measuring chemicals, solutions, etc. for chemical reactions or other processes such as mixing, cooling, precipitation, boiling, or analysis. There are several types of laboratory flasks, all of which have different functions within the laboratory. Flasks, because of their use, can be divided into: Reaction flasks, which are spherical and are accompanied by their necks, at the ends of which are ground glass joints to and connect to the rest of the apparatus; the reaction flask is made of thick glass and they can tolerate large pressure differences, with the result that you can keep two both in a reaction under vacuum, pressure, sometimes simultaneously. Some varieties are: Multiple neck flasks, which can have two to five, or less six necks, each topped by ground glass connections are used in more complex reactions that require the controlled mixing of multiple reagents.
Schlenk flask is a spherical flask with a ground glass opening and a hose outlet with a vacuum stopcock. The tap makes it easy to connect the flask to a vacuum-nitrogen line through the hose and carrying out the reaction either in vacuum or in atmosphere nitrogen Distillation flasks, which are intended to contain mixtures, which are subject to distillation, as well as to receive the products of distillation, distillation flasks are available in various shapes. Similar to the reaction flask, the distillation flasks have only one narrow neck and a ground glass joint and are made of thinner glass than the reaction flask, so that it is easier to heat, they are sometimes spherical, test tube shaped, or pear-shaped known as a Kjeldahl Flask, due to its use with Kjeldahl bulbs. Reagent flasks are a flat-bottomed flask, which can thus be conveniently placed on the table or in a cabinet; these flasks cannot withstand too much pressure or temperature differences, due to the stresses which arise in a flat bottom, these flasks are made of weaker glass than reaction flasks.
Certain types of flasks are supplied with a ground glass stopper in them, others that are threaded neck and closes with an appropriate nut or automatic dispenser, these flasks are available in two standard shapes: Round-bottom flasks are shaped like a tube emerging from the top of a sphere. The flasks are long neck, they can be used in the heating a product. These types of flask are alternatively called Florence flasks. Flasks with flat bottom. Cassia flasks, for the analysis of aldehyde determination, approx. 100 ml, neck graduated 0 - 6: 0,1 ml. Erlenmeyer flask - is shaped like a cone completed by the ground joint, the conical flasks are popular because of their low price and portability Volumetric flask is used for preparing liquids with volumes of high precision, it is a flask with an pear-shaped body and a long neck with a circumferential fill line. Dewar flask is a double-walled flask having a near-vacuum between the two walls; these come in a variety of sizes. Evaporating flasks pear shaped, with socket or with flange.
Powder flasks, for drying of powdered substances, pear shaped, with socket Retorts are simplified distillation apparatuses, with long, down turned necks, round bases. They have been replaced by condensers. Büchner flask or Sidearm flask or Suction flask - they are a flat-bottomed flask, but made of thick and resistant glass, they are a cone shape - similar to the shape of an Erlenmeyer flask, but have side neck affixed to the side, 2 / 3 up from the bottom. The flasks are used to cooperate with vacuum aspirator or vacuum pumps in the vacuum filtration, or as additional security during the distillation and other processes carried out under reduced pressure. Culture flasks for growing cells are designed to improve aeration by including baffles that aid in mixing when placed on a shaker table. Beaker Many of these flasks can be wrapped in a protective outer layer of glass, leaving a gap between the inner and outer wall
A Schlenk flask, or Schlenk tube is a reaction vessel used in air-sensitive chemistry, invented by Wilhelm Schlenk. It has a side arm fitted with a PTFE or ground glass stopcock, which allows the vessel to be evacuated or filled with gases; these flasks are connected to Schlenk lines, which allow both operations to be done easily. Schlenk flasks and Schlenk tubes, like most laboratory glassware, are made from borosilicate glass such as Pyrex. Schlenk flasks are round-bottomed, they may be purchased off-the-shelf from laboratory suppliers or made from round-bottom flasks or glass tubing by a skilled glassblower. Before solvent or reagents are introduced into a Schlenk flask, the flask is dried and the atmosphere of the flask is exchanged with an inert gas. A common method of exchanging the atmosphere of the flask is to flush the flask out with an inert gas; the gas can be introduced via a wide bore needle. The contents of the flask exit the flask through the neck portion of the flask; the needle method has the advantage that the needle can be placed at the bottom of the flask to better flush out the atmosphere of the flask.
Flushing a flask out with an inert gas can be inefficient for large flasks and is impractical for complex apparatus. An alternative way to exchange the atmosphere of a Schlenk flask is to use one or more "vac-refill" cycles using a vacuum-gas manifold known as a Schlenk line; this involves replacing the resulting vacuum with an inert gas. For example, evacuation of the flask to 1 mmHg and replenishing the atmosphere with 760 mmHg inert gas leaves 0.13% of the original atmosphere. Two such vac-refill cycles leaves 0.000173%. Most Schlenk lines and achieve a vacuum of 1 mmHg; when using Schlenk systems, including flasks, the use of grease is necessary at stopcock valves and ground glass joints to provide a gas tight seal and prevent glass pieces from fusing. In contrast, teflon plug valves may have a trace of oil as a lubricant but no grease. In the following text any "connection" is assumed to be rendered air free through a series of vac-refill cycles; the standard Schlenk flask is a round bottom, pear-shaped, or tubular flask with a ground glass joint and a side arm.
The side arm contains a valve a greased stopcock, used to control the flask's exposure to a manifold or the atmosphere. This allows a material to be added to a flask through the ground glass joint, capped with a septum; this operation can, for example, be done in a glove box. The flask can be removed from the glove box and taken to a Schlenk line. Once connected to the Schlenk line, the inert gas and/or vacuum can be applied to the flask as required. While the flask is connected to the line under a positive pressure of inert gas, the septum can be replaced with other apparatus, for example a reflux condenser. Once the manipulations are complete, the contents can be vacuum dried and placed under a static vacuum by closing the side arm valve; these evacuated flasks can be taken back into a glove box for further manipulation or storage of the flasks' contents. A "bomb" flask is subclass of Schlenk flask which includes all flasks that have only one opening accessed by opening a Teflon plug valve; this design allows a Schlenk bomb to be sealed more than a standard Schlenk flask if its septum or glass cap is wired on.
Schlenk bombs include structurally sound shapes such as heavy walled tubes. Schlenk bombs are used to conduct reactions at elevated pressures and temperatures as a closed system. In addition, all Schlenk bombs are designed to withstand the pressure differential created by the ante-chamber when pumping solvents into a glove box. In practice Schlenk bombs can perform many of the functions of a standard Schlenk flask; when the opening is used to fit a bomb to a manifold, the plug can still be removed to add or remove material from the bomb. In some situations, Schlenk bombs are less convenient than standard Schlenk flasks: they lack an accessible ground glass joint to attach additional apparatus; the name "bomb" is applied to containers used under pressure such as a bomb calorimeter. While glass does not equal the pressure rating and mechanical strength of most metal containers, it does have several advantages. Glass allows visual inspection of a reaction in progress, it is inert to a wide range of reaction conditions and substrates, it is more compatible with common laboratory glassware, it is more cleaned and checked for cleanliness.
A Straus flask is subclass of "bomb" flask developed by Kontes Glass Company used for storing dried and degassed solvents. Straus flasks are sometimes referred to as solvent bombs — a name which applies to any Schlenk bomb dedicated to storing solvent. Straus flasks are differentiated from other "bombs" by their neck structure. Two necks emerge from one larger than the other; the larger neck ends in a ground glass joint and is permanently partitioned by blown glass from direct access to the flask. The smaller neck includes the threading required for a teflon plug to be screwed in perpendicular to the flask; the two necks are joined through a glass tube. The ground glass joint can be connected to a manifold directly or through an hosing. Once connected
A Bunsen burner, named after Robert Bunsen, is a common piece of laboratory equipment that produces a single open gas flame, used for heating and combustion. The gas can be natural gas or a liquefied petroleum gas, such as propane, butane, or a mixture of both. In 1852 the University of Heidelberg promised him a new laboratory building; the city of Heidelberg had begun to install coal-gas street lighting, so the university laid gas lines to the new laboratory. The designers of the building intended to use the gas not just for illumination, but in burners for laboratory operations. For any burner lamp, it was desirable to minimize luminosity. However, existing laboratory burner lamps left much to be desired not just in terms of the heat of the flame, but regarding economy and simplicity. While the building was still under construction in late 1854, Bunsen suggested certain design principles to the university's mechanic, Peter Desaga, asked him to construct a prototype. Similar principles had been used in an earlier burner design by Michael Faraday, as well as in a device patented in 1856 by the gas engineer R. W. Elsner.
The Bunsen/Desaga design succeeded in generating a hot, non-luminous flame by mixing the gas with air in a controlled fashion before combustion. Desaga created adjustable slits for air at the bottom of the cylindrical burner, with the flame igniting at the top. By the time the building opened early in 1855. Two years Bunsen published a description, many of his colleagues soon adopted the design. Bunsen burners are now used in laboratories all around the world; the device in use today safely burns a continuous stream of a flammable gas such as natural gas or a liquefied petroleum gas such as propane, butane, or a mixture of both. The hose barb is connected to a gas nozzle on the laboratory bench with rubber tubing. Most laboratory benches are equipped with multiple gas nozzles connected to a central gas source, as well as vacuum and steam nozzles; the gas flows up through the base through a small hole at the bottom of the barrel and is directed upward. There are open slots in the side of the tube bottom to admit air into the stream using the Venturi effect, the gas burns at the top of the tube once ignited by a flame or spark.
The most common methods of lighting the burner are using a spark lighter. The amount of air mixed with the gas stream affects the completeness of the combustion reaction. Less air yields an incomplete and thus cooler reaction, while a gas stream well mixed with air provides oxygen in a stoichiometric amount and thus a complete and hotter reaction; the air flow can be controlled by opening or closing the slot openings at the base of the barrel, similar in function to the choke in a carburettor. If the collar at the bottom of the tube is adjusted so more air can mix with the gas before combustion, the flame will burn hotter, appearing blue as a result. If the holes are closed, the gas will only mix with ambient air at the point of combustion, that is, only after it has exited the tube at the top; this reduced mixing produces an incomplete reaction, producing a cooler but brighter yellow, called the "safety flame" or "luminous flame". The yellow flame is luminous due to small soot particles in the flame, which are heated to incandescence.
The yellow flame is considered "dirty" because it leaves a layer of carbon on whatever it is heating. When the burner is regulated to produce a hot, blue flame, it can be nearly invisible against some backgrounds; the hottest part of the flame is the tip of the inner flame, while the coolest is the whole inner flame. Increasing the amount of fuel gas flow through the tube by opening the needle valve will increase the size of the flame. However, unless the airflow is adjusted as well, the flame temperature will decrease because an increased amount of gas is now mixed with the same amount of air, starving the flame of oxygen; the burner is placed underneath a laboratory tripod, which supports a beaker or other container. The burner will be placed on a suitable heatproof mat to protect the laboratory bench surface. A Bunsen burner is used in microbiology laboratories to sterilise pieces of equipment and to produce an updraft that forces airborne contaminants away from the working area. Other burners based on the same principle exist.
The most important alternatives to the Bunsen burner are: Teclu burner – The lower part of its tube is conical, with a round screw nut below its base. The gap, set by the distance between the nut and the end of the tube, regulates the influx of the air in a way similar to the open slots of the Bunsen burner; the Teclu burner provides better mixing of air and fuel and can achieve higher flame temperatures than the Bunsen burner. Meker burner – The lower part of its tube has more openings with larger total cross-section, admitting more air and facilitating better mixing of air and gas; the tube is wider and its top is covered with a wire grid. The grid separates the flame into an array of smaller flames with a common external envelope, prevents flashback to the bottom of the tube, a risk at high air-to-fuel ratios and limits the maximum rate of air intake in a conventional Bunsen burner. Flame temperatures of up to 1,100–1,200 °C are achievable if properly used; the flame burns without noise, unlike the Bunsen or Teclu burners.
Tirrill burner – The base of the burner has a needle valve which allows the regulation of gas intake directly from the Burner, rather than from the gas source. Maximum temperature of flame can reach 1560 °C. Alcohol burner Heating mantle
Liquid nitrogen is nitrogen in a liquid state at an low temperature. It is a colorless liquid with a density of 0.807 g/ml at its boiling point and a dielectric constant of 1.43. Nitrogen was first liquefied at the Jagiellonian University on 15 April 1883 by Polish physicists, Zygmunt Wróblewski and Karol Olszewski, it is produced industrially by fractional distillation of liquid air. Liquid nitrogen is referred to by the abbreviation, LN2 or "LIN" or "LN" and has the UN number 1977. Liquid nitrogen is a diatomic liquid, which means that the diatomic character of the covalent N bonding in N2 gas is retained after liquefaction. Liquid nitrogen is a cryogenic fluid; when appropriately insulated from ambient heat, liquid nitrogen can be stored and transported, for example in vacuum flasks. The temperature is held constant at 77 K by slow boiling of the liquid, resulting in the evolution of nitrogen gas. Depending on the size and design, the holding time of vacuum flasks ranges from a few hours to a few weeks.
The development of pressurised super-insulated vacuum vessels has enabled liquefied nitrogen to be stored and transported over longer time periods with losses reduced to 2% per day or less. The temperature of liquid nitrogen can be reduced to its freezing point 63 K by placing it in a vacuum chamber pumped by a vacuum pump. Liquid nitrogen's efficiency as a coolant is limited by the fact that it boils on contact with a warmer object, enveloping the object in insulating nitrogen gas; this effect, known as the Leidenfrost effect, applies to any liquid in contact with an object hotter than its boiling point. Faster cooling may be obtained by plunging an object into a slush of liquid and solid nitrogen rather than liquid nitrogen alone. Liquid nitrogen is a compact and transported source of dry nitrogen gas, as it does not require pressurization. Further, its ability to maintain temperatures far below the freezing point of water makes it useful in a wide range of applications as an open-cycle refrigerant, including: in cryotherapy for removing unsightly or malignant skin lesions such as warts and actinic keratosis to store cells at low temperature for laboratory work in cryogenics in a cryophorus to demonstrate rapid freezing by evaporation as a backup nitrogen source in hypoxic air fire prevention systems as a source of dry nitrogen gas for the immersion and transportation of food products for the cryopreservation of blood, reproductive cells, other biological samples and materials to preserve tissue samples from surgical excisions for future studies to facilitate cryoconservation of animal genetic resources to freeze water and oil pipes in order to work on them in situations where a valve is not available to block fluid flow to the work area.
See molecular gastronomy. in container inerting and pressurisation by injecting a controlled amount of liquid nitrogen just prior to sealing or capping as a cosmetic novelty giving a smoky, bubbling "cauldron effect" to drinks. See liquid nitrogen cocktail; as an energy storage medium branding cattle The culinary use of liquid nitrogen is mentioned in an 1890 recipe book titled Fancy Ices authored by Mrs. Agnes Marshall, but has been employed in more recent times by restaurants in the preparation of frozen desserts, such as ice cream, which can be created within moments at the table because of the speed at which it cools food; the rapidity of chilling leads to the formation of smaller ice crystals, which provides the dessert with a smoother texture. The technique is employed by chef Heston Blumenthal who has used it at his restaurant, The Fat Duck to create frozen dishes such as egg and bacon ice cream. Liquid nitrogen has become popular in the preparation of cocktails because it can be used to chill glasses or freeze ingredients.
It is added to drinks to create a smoky effect, which occurs as tiny droplets of the liquid nitrogen come into contact with the surrounding air, condensing the vapour, present. Because the liquid-to-gas expansion ratio of nitrogen is 1:694 at 20 °C, a tremendous amount of force can be generated if liquid nitrogen is vaporized in an enclosed space. In an incident on January 12, 2006 at Texas A&M University, the pressure-relief devices of a tank of liquid nitrogen were malfunctioning and sealed; as a result of the subsequent pressure buildup, the tank failed catastrophically. The force of the explosion was sufficient to propel the tank through the ceiling above it, shatter a reinforced concrete beam below it, blow the walls of t
Distillation is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation. Distillation may result in complete separation, or it may be a partial separation that increases the concentration of selected components in the mixture. In either case, the process exploits differences in the volatility of the mixture's components. In industrial chemistry, distillation is a unit operation of universal importance, but it is a physical separation process, not a chemical reaction. Distillation has many applications. For example: Distillation of fermented products produces distilled beverages with a high alcohol content or separates out other fermentation products of commercial value. Distillation is an traditional method of desalination. In the fossil fuel industry, oil stabilization is a form of partial distillation that reduces vapor pressure of crude oil, thereby making it safe for storage and transport as well as reducing the atmospheric emissions of volatile hydrocarbons.
In midstream operations at oil refineries, distillation is a major class of operation for transforming crude oil into fuels and chemical feed stocks. Cryogenic distillation leads to the separation of air into its components – notably oxygen and argon – for industrial use. In the field of industrial chemistry, large amounts of crude liquid products of chemical synthesis are distilled to separate them, either from other products, from impurities, or from unreacted starting materials. An installation used for distillation of distilled beverages, is called a distillery; the distillation equipment at a distillery is a still. In 1975 Paolo Rovesti a chemist and pharmacist who became known as"father of Phytocosmetics" discovered a terracota distillation apparatus in the Indus valley in West Pakistan which dates from around 3000 BC. Early evidence of distillation was found on Akkadian tablets dated circa 1200 BC describing perfumery operations; the tablets provided textual evidence that an early primitive form of distillation was known to the Babylonians of ancient Mesopotamia.
Early evidence of distillation was found related to alchemists working in Alexandria in Roman Egypt in the 1st century. Distilled water has been in use since at least c. 200, when Alexander of Aphrodisias described the process. Work on distilling other liquids continued in early Byzantine Egypt under Zosimus of Panopolis in the 3rd century. Distillation was practiced in the ancient Indian subcontinent, evident from baked clay retorts and receivers found at Taxila and Charsadda in modern Pakistan, dating back to the early centuries of the Common Era; these "Gandhara stills" were only capable of producing weak liquor, as there was no efficient means of collecting the vapors at low heat. Distillation in China may have begun during the Eastern Han dynasty, but the distillation of beverages began in the Jin and Southern Song dynasties, according to archaeological evidence. Clear evidence of the distillation of alcohol comes from the Arab chemist Al-Kindi in 9th-century Iraq; the process spread to Italy, where it was described by the School of Salerno in the 12th century.
Fractional distillation was developed by Tadeo Alderotti in the 13th century. A still was found in an archaeological site in Qinglong, Hebei province, in China, dating back to the 12th century. Distilled beverages were common during the Yuan dynasty. In 1500, German alchemist Hieronymus Braunschweig published Liber de arte destillandi, the first book dedicated to the subject of distillation, followed in 1512 by a much expanded version. In 1651, John French published The Art of Distillation, the first major English compendium on the practice, but it has been claimed that much of it derives from Braunschweig's work; this includes diagrams with people in them showing the industrial rather than bench scale of the operation. As alchemy evolved into the science of chemistry, vessels called retorts became used for distillations. Both alembics and retorts are forms of glassware with long necks pointing to the side at a downward angle to act as air-cooled condensers to condense the distillate and let it drip downward for collection.
Copper alembics were invented. Riveted joints were kept tight by using various mixtures, for instance a dough made of rye flour; these alembics featured a cooling system around the beak, using cold water, for instance, which made the condensation of alcohol more efficient. These were called pot stills. Today, the retorts and pot stills have been supplanted by more efficient distillation methods in most industrial processes. However, the pot still is still used for the elaboration of some fine alcohols, such as cognac, Scotch whisky, Irish whiskey and some vodkas. Pot stills made of various materials are used by bootleggers in various countries. Small pot stills are sold for use in the domestic production of flower water or essential oils. Early forms of distillation involved batch processes using one condensation. Purity was improved by further distillation of the condensate. Greater volumes were processed by repeating the distillation. Chemists carried out as many as 500 to 600 distillations in order to obtain a pure compound.
In the early 19th century, the basics of modern techniques, including pre-heating and reflux, were developed. In 1822, Anthony Perrier developed one of the first continuous stills, in 1826, Robert Stein improved that design to make his patent still. In 1830, Aeneas Coffey got a patent for improving the design f
A heating mantle, or isomantle, is a piece of laboratory equipment used to apply heat to containers, as an alternative to other forms of heated bath. In contrast to other heating devices, such as hotplates or Bunsen burners, glassware containers may be placed in direct contact with the heating mantle without increasing the risk of the glassware shattering, because the heating element of a heating mantle is insulated from the container so as to prevent excessive temperature gradients. Heating mantles may have various forms. In a common arrangement, electric wires are embedded within a strip of fabric that can be wrapped around a flask; the current supplied to the device, hence the temperature achieved, is regulated by a rheostat. This type of heating mantle is quite useful for maintaining an intended temperature within a separatory funnel, for example, after the contents of a reaction have been removed from a primary heat source. Another variety of heating mantle may resemble a paint can and is constructed as a "basket" within a cylindrical canister.
The rigid metal exterior supports a "basket" made of fabric and includes heating elements within the body of the heating mantle. To heat an object, it is placed within the basket of the heating mantle. In further contrast to other methods of applying heat to a flask, such as an oil bath or water bath, using a heating mantle generates no liquid residue to drip off the flask. Heating mantles distribute heat evenly over the surface of the flask and exhibit less tendency to generate harmful hotspots. Heating element Laboratory equipment Wire gauze Double boiler
Standardization or standardisation is the process of implementing and developing technical standards based on the consensus of different parties that include firms, interest groups, standards organizations and governments Standardization can help to maximize compatibility, safety, repeatability, or quality. It can facilitate commoditization of custom processes. In social sciences, including economics, the idea of standardization is close to the solution for a coordination problem, a situation in which all parties can realize mutual gains, but only by making mutually consistent decisions; this view includes the case of "spontaneous standardization processes", to produce de facto standards. Standard weights and measures were developed by the Indus Valley Civilization; the centralized weight and measure system served the commercial interest of Indus merchants as smaller weight measures were used to measure luxury goods while larger weights were employed for buying bulkier items, such as food grains etc.
Weights existed in categories. Technical standardisation enabled gauging devices to be used in angular measurement and measurement for construction. Uniform units of length were used in the planning of towns such as Lothal, Kalibangan, Dolavira and Mohenjo-daro; the weights and measures of the Indus civilization reached Persia and Central Asia, where they were further modified. Shigeo Iwata describes the excavated weights unearthed from the Indus civilization: A total of 558 weights were excavated from Mohenjodaro and Chanhu-daro, not including defective weights, they did not find statistically significant differences between weights that were excavated from five different layers, each measuring about 1.5 m in depth. This was evidence; the 13.7-g weight seems to be one of the units used in the Indus valley. The notation was based on decimal systems. 83% of the weights which were excavated from the above three cities were cubic, 68% were made of chert. The implementation of standards in industry and commerce became important with the onset of the Industrial Revolution and the need for high-precision machine tools and interchangeable parts.
Henry Maudslay developed the first industrially practical screw-cutting lathe in 1800. This allowed for the standardisation of screw thread sizes for the first time and paved the way for the practical application of interchangeability to nuts and bolts. Before this, screw threads were made by chipping and filing. Nuts were rare. Metal bolts passing through wood framing to a metal fastening on the other side were fastened in non-threaded ways. Maudslay standardized the screw threads used in his workshop and produced sets of taps and dies that would make nuts and bolts to those standards, so that any bolt of the appropriate size would fit any nut of the same size; this was a major advance in workshop technology. Maudslay's work, as well as the contributions of other engineers, accomplished a modest amount of industry standardization. Joseph Whitworth's screw thread measurements were adopted as the first national standard by companies around the country in 1841, it came to be known as the British Standard Whitworth, was adopted in other countries.
This new standard specified a 55° thread angle and a thread depth of 0.640327p and a radius of 0.137329p, where p is the pitch. The thread pitch increased with diameter in steps specified on a chart. An example of the use of the Whitworth thread is the Royal Navy's Crimean War gunboats; these were the first instance of "mass-production" techniques being applied to marine engineering. With the adoption of BSW by British railway lines, many of which had used their own standard both for threads and for bolt head and nut profiles, improving manufacturing techniques, it came to dominate British manufacturing. American Unified Coarse was based on the same imperial fractions; the Unified thread angle has flattened crests. Thread pitch is the same in both systems except that the thread pitch for the 1⁄2 in bolt is 12 threads per inch in BSW versus 13 tpi in the UNC. By the end of the 19th century, differences in standards between companies, was making trade difficult and strained. For instance, an iron and steel dealer recorded his displeasure in The Times: "Architects and engineers specify such unnecessarily diverse types of sectional material or given work that anything like economical and continuous manufacture becomes impossible.
In this country no two professional men are agreed upon the size and weight of a girder to employ for given work." The Engineering Standards Committee was established in London in 1901 as the world's first national standards body. It subsequently extended its standardization work and became the British Engineering Standards Association in 1918, adopting the name British Standards Institution in 1931 after receiving its Royal Charter in 1929; the national standards were adopted universally throughout the country, enabled the markets to act more rationally and efficiently, with an increased level of cooperation. After the First World War, similar national bodies were established in other countries; the Deutsches Institut für Normung was set up in Germany in 1917, followed by its counterparts, the American National Standard Institute and the French Commissi