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A boiler is a closed vessel where drinking water or other fluid is heated. The fluid does not always boil. (In THE UNITED STATES, the term "furnace" is normally used if the reason is never to boil the liquid.) The heated or vaporized liquid exits the boiler for use in various processes or heating applications,[1 - [2 - including water heating, central heating, boiler-based power era, cooking, and sanitation. Materials The pressure vessel of the boiler is usually manufactured from steel (or alloy steel), or historically of wrought iron. Stainless steel, especially of the austenitic types, is not used in wetted parts of boilers thanks to stress and corrosion corrosion breaking.[3 - However, ferritic stainless is often found in superheater sections that will not come in contact with boiling drinking water, and electrically heated stainless shell boilers are allowed under the Western "Pressure Equipment Directive" for production of steam for sterilizers and disinfectors.[4 - https://en.wikipedia.org/wiki/Boiler - https://en.wikipedia.org/wiki/Boiler In live steam models, copper or brass is often used since it is more easily fabricated in smaller size boilers. Historically, copper was often used for fireboxes (especially for vapor locomotives), due to its better formability and higher thermal conductivity; however, in more recent times, the high price of copper often makes this an uneconomic choice and cheaper substitutes (such as steel) are used instead. For a lot of the Victorian "age of vapor", the only materials used for boilermaking was the highest grade of wrought iron, with set up by rivetting. This iron was from specialist ironworks, such as at Cleator Moor (UK), observed for the high quality of their rolled plate and its suitability for high-reliability use in critical applications, such as high-pressure boilers. In the 20th century, design practice instead relocated towards the utilization of steel, which is more powerful and cheaper, with welded building, which is quicker and requires less labour. It should be observed, however, that wrought iron boilers corrode significantly slower than their modern-day steel counterparts, and are less vunerable to localized pitting and stress-corrosion. This makes the longevity of older wrought-iron boilers far superior to those of welded metal boilers. Cast iron can be utilized for the heating system vessel of home drinking water heaters. Although such heaters are usually termed "boilers" in a few countries, their purpose is to create warm water usually, not steam, and they also run at low pressure and stay away from boiling. The brittleness of cast iron helps it be impractical for high-pressure steam boilers. Boiler Repairs Colindale, Kingsbury, NW9, Boiler Breakdown Emergency Service http://boiler-repairs-colindale.co.uk - Boiler Repairs Colindale, Kingsbury, NW9, Boiler Breakdown Emergency Service! Energy The source of heating for a boiler is combustion of any of several fuels, such as wood, coal, oil, or gas. Electric steam boilers use resistance- or immersion-type heating elements. Nuclear fission is utilized as a heat source for producing steam also, either straight (BWR) or, generally, in specialised high temperature exchangers called "steam generators" (PWR). Heat recovery vapor generators (HRSGs) use heat rejected from other processes such as gas turbine. Boiler efficiency there are two methods to gauge the boiler efficiency 1) direct method 2) indirect method Immediate method -direct method of boiler efficiency test is more usable or even more common boiler efficiency =Q*((Hg-Hf)/q)*(GCV *100 ) Q =Total vapor flow Hg= Enthalpy of saturated steam in k cal/kg Hf =Enthalpy of give food to water in kcal/kg q= quantity of gasoline use in kg/hr GCV =gross calorific value in kcal/kg like pet coke (8200 kcal/KG) indirect method -to measure the boiler efficiency in indirect method, we are in need of a subsequent parameter like Ultimate analysis of gas (H2,S2,S,C moisture constraint, ash constraint) percentage of O2 or CO2 at flue gas flue gas temperature at outlet ambient temperature in deg c and humidity of air in kg/kg GCV of fuel in kcal/kg ash percentage in combustible fuel GCV of ash in kcal/kg Configurations Boilers can be classified in to the following configurations: Pot boiler or Haycock boiler/Haystack boiler: a primitive "kettle" in which a open fire heats a partially filled drinking water pot from below. 18th century Haycock boilers produced and stored large amounts of very low-pressure vapor generally, hardly above that of the atmosphere often. These could burn wood or frequently, coal. Efficiency was suprisingly low. Flued boiler with one or two large flues-an early forerunner or kind of fire-tube boiler. Diagram of a fire-tube boiler Fire-tube boiler: Here, water partially fills a boiler barrel with a little volume still left above to accommodate the steam (steam space). This is the kind of boiler used in all steam locomotives nearly. Heat source is inside a furnace or firebox that needs to be kept completely surrounded by water in order to keep the heat range of the heating system surface below the boiling point. The furnace can be situated at one end of the fire-tube which lengthens the road of the hot gases, thus augmenting the heating system surface which can be further increased by causing the gases invert direction through another parallel pipe or a bundle of multiple tubes (two-pass or come back flue boiler); alternatively the gases may be studied along the edges and then beneath the boiler through flues (3-move boiler). In case there is a locomotive-type boiler, a boiler barrel expands from the firebox and the hot gases go through a bundle of fire tubes inside the barrel which greatly increases the heating system surface in comparison to a single pipe and further increases heat transfer. Fire-tube boilers have a comparatively low rate of steam creation usually, but high steam storage capacity. Fire-tube boilers mostly burn solid fuels, but are easily adaptable to those of the liquid or gas variety. Diagram of a water-tube boiler. Water-tube boiler: In this kind, tubes filled with drinking water are arranged inside a furnace in a true amount of possible configurations. Usually the water pipes connect large drums, the lower ones containing water and the top ones water and steam; in other cases, like a mono-tube boiler, water is circulated by a pump through a succession of coils. This type generally provides high vapor creation rates, but less storage capacity than the above mentioned. Water pipe boilers can be designed to exploit any high temperature source and are generally preferred in high-pressure applications because the high-pressure drinking water/steam is contained within small size pipes which can withstand the pressure with a thinner wall structure. Flash boiler: A flash boiler is a specialized type of water-tube boiler where tubes are close jointly and drinking water is pumped through them. A flash boiler differs from the kind of mono-tube vapor generator in which the tube is permanently filled up with water. Super fast boiler, the pipe is held so hot that the water give food to is quickly flashed into vapor and superheated. Flash boilers experienced some use in cars in the 19th century and this use continued in to the early 20th century. . 1950s design vapor locomotive boiler, from a Victorian Railways J class Fire-tube boiler with Water-tube firebox. Sometimes the two above types have been mixed in the following manner: the firebox consists of an assembly of water tubes, called thermic siphons. The gases go through a conventional firetube boiler then. Water-tube fireboxes were installed in many Hungarian locomotives,[citation needed - but have met with little success in other countries. Sectional boiler. Within a cast iron sectional boiler, sometimes called a "pork chop boiler" the water is contained inside solid iron areas.[citation needed - These sections are assembled on site to create the finished boiler. Safety See also: Boiler explosion To define and secure boilers safely, some professional specialized organizations like the American Society of Mechanical Designers (ASME) develop criteria and regulation rules. For instance, the ASME Boiler and Pressure Vessel Code is a standard providing a wide range of guidelines and directives to ensure compliance of the boilers and other pressure vessels with basic safety, security and design standards.[5 - Historically, boilers were a source of many serious injuries and property destruction due to badly understood engineering principles. Thin and brittle metal shells can rupture, while poorly welded or riveted seams could open up, leading to a violent eruption of the pressurized vapor. When water is converted to steam it expands to over 1,000 times its original quantity and moves down vapor pipes at over 100 kilometres each hour. As a result of this, steam is a superb way of moving energy and high temperature around a site from a central boiler house to where it is needed, but with no right boiler give food to water treatment, a steam-raising flower will suffer from size corrosion and formation. At best, this increases energy costs and can lead to poor quality vapor, reduced efficiency, shorter plant life and unreliable procedure. At worst, it can lead to catastrophic failing and loss of life. Collapsed or dislodged boiler tubes can also aerosol scalding-hot steam and smoke from the air intake and firing chute, injuring the firemen who weight the coal into the fireplace chamber. Extremely large boilers providing a huge selection of horsepower to use factories can potentially demolish entire buildings.[6 - A boiler which has a loss of feed water and is permitted to boil dry out can be hugely dangerous. If feed water is sent in to the unfilled boiler then, the tiny cascade of inbound drinking water instantly boils on connection with the superheated metal shell and leads to a violent explosion that cannot be managed even by basic safety steam valves. Draining of the boiler can also happen if a leak occurs in the vapor supply lines that is bigger than the make-up drinking water source could replace. The Hartford Loop was developed in 1919 by the Hartford Vapor Boiler and INSURANCE PROVIDER as a strategy to assist in preventing this condition from happening, and thereby reduce their insurance promises.[7 - [8 - Superheated steam boiler A superheated boiler on a steam locomotive. Main article: Superheater Most boilers produce steam to be utilized at saturation heat; that is, saturated steam. Superheated vapor boilers vaporize water and then further temperature the steam in a superheater. This provides vapor at higher heat, but can decrease the overall thermal efficiency of the steam generating place because the higher steam temp requires a higher flue gas exhaust temperature.[citation needed - There are many ways to circumvent this problem, by giving an economizer that heats the give food to drinking water typically, a combustion air heater in the hot flue gas exhaust path, or both. You will find advantages to superheated steam that may, and often will, increase overall efficiency of both steam generation and its utilization: increases in input heat to a turbine should outweigh any cost in additional boiler complication and expense. There could be practical limitations in using moist vapor also, as entrained condensation droplets will harm turbine blades. Superheated steam presents unique safety concerns because, if any system component fails and allows steam to flee, the high pressure and temperature can cause serious, instantaneous harm to anyone in its path. Since the escaping steam will at first be completely superheated vapor, detection can be difficult, although the intense heat and sound from such a leak indicates its presence clearly. Superheater procedure is similar to that of the coils on an air conditioning unit, although for a different purpose. The vapor piping is directed through the flue gas path in the boiler furnace. The temperatures in this area is typically between 1,300 and 1,600 °C (2,372 and 2,912 °F). Some superheaters are radiant type; that is, they absorb temperature by radiation. Others are convection type, absorbing warmth from a liquid. Some are a mixture of both types. Through either method, the extreme heat in the flue gas path will heat the superheater steam piping and the steam within also. While the heat range of the steam in the superheater rises, the pressure of the vapor will not and the pressure remains exactly like that of the boiler.[9 - Almost all steam superheater system designs remove droplets entrained in the steam to avoid damage to the turbine blading and associated piping. Supercritical steam generator Boiler for a charged power herb. Main article: Supercritical steam generator Supercritical steam generators are generally used for the production of energy. They operate at supercritical pressure. As opposed to a "subcritical boiler", a supercritical steam generator operates at such a high pressure (over 3,200 psi or 22 MPa) that the physical turbulence that characterizes boiling ceases to occur; the fluid is neither liquid nor gas but a super-critical fluid. There is absolutely no era of steam bubbles within water, because the pressure is above the critical pressure point at which vapor bubbles can form. As the fluid expands through the turbine phases, its thermodynamic condition drops below the critical point as it can work turning the turbine which turns the power generator from which power is eventually extracted. The fluid at that time may be a mix of vapor and liquid droplets as it passes into the condenser. This results in somewhat less gasoline use and therefore less greenhouse gas production. The word "boiler" should not be used for a supercritical pressure steam generator, as no "boiling" occurs in this device. Boiler Repairs Colindale, Kingsbury, NW9, Boiler Breakdown Emergency Service http://boiler-repairs-colindale.co.uk - Boiler Repairs Colindale, Kingsbury, NW9, Boiler Breakdown Emergency Service! Accessories Boiler fittings and accessories Pressuretrols to regulate the steam pressure in the boiler. Boilers generally have 2 or 3 3 pressuretrols: a manual-reset pressuretrol, which functions as a security by setting the top limit of vapor pressure, the working pressuretrol, which settings when the boiler fires to keep up pressure, and for boilers equipped with a modulating burner, a modulating pressuretrol which settings the quantity of fire. Basic safety valve: It is utilized to alleviate pressure and stop possible explosion of a boiler. Water level indicators: They show the operator the level of fluid in the boiler, known as a sight glass also, water gauge or water column. Bottom blowdown valves: They offer a means for removing solid particulates that condense and rest on underneath of the boiler. As the name indicates, this valve is usually located directly on the bottom of the boiler, and is sometimes opened to use the pressure in the boiler to drive these particulates out. Constant blowdown valve: This allows a small level of water to escape continuously. Its purpose is to avoid the water in the boiler becoming saturated with dissolved salts. Saturation would lead to foaming and cause water droplets to be transported over with the steam - a disorder known as priming. Blowdown is also often used to monitor the chemistry of the boiler drinking water. Trycock: a kind of valve that is often use to manually check a liquid level in a tank. Most commonly entirely on a drinking water boiler. Flash tank: High-pressure blowdown enters this vessel where in fact the vapor can 'flash' safely and become used in a low-pressure system or be vented to atmosphere while the ambient pressure blowdown moves to drain. Automatic blowdown/continuous heat recovery system: This technique allows the boiler to blowdown only when make-up water is moving to the boiler, thereby transferring the utmost amount of heat possible from the blowdown to the makeup water. No flash container is generally needed as the blowdown discharged is close to the temperatures of the make-up water. Hand openings: These are steel plates installed in openings in "header" to permit for inspections & installation of tubes and inspection of inner surfaces. Steam drum internals, a series of display, scrubber & cans (cyclone separators). Low-water cutoff: It really is a mechanical means (usually a float change) that is utilized to turn off the burner or shut off gasoline to the boiler to prevent it from jogging once the drinking water moves below a certain point. If a boiler is "dry-fired" (burned without water in it) it can cause rupture or catastrophic failure. Surface blowdown range: It offers a means for removing foam or other lightweight non-condensible chemicals that tend to float together with water inside the boiler. Circulating pump: It is made to circulate drinking water back to the boiler after they have expelled a few of its heat. Feedwater check valve or clack valve: A non-return stop valve in the feedwater series. This may be fitted to the comparative part of the boiler, below water level just, or to the top of the boiler.[10 - Top feed: Within this design for feedwater injection, the water is fed to the top of the boiler. This can reduce boiler exhaustion triggered by thermal stress. By spraying the feedwater over some trays water is quickly heated which can reduce limescale. Desuperheater pipes or bundles: Some pipes or bundles of tubes in water drum or the steam drum made to cool superheated steam, in order to supply auxiliary equipment that does not need, or may be damaged by, dry steam. Chemical substance injection line: A link with add chemicals for controlling feedwater pH. Steam accessories Main steam stop valve: Steam traps: Main steam stop/check valve: It can be used on multiple boiler installations. Combustion accessories Gasoline oil system:fuel oil heaters Gas system: Coal system: Soot blower Other essential items Pressure gauges: Feed pumps: Fusible plug: Inspectors test pressure measure attachment: Name plate: Registration plate: