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'A boiler is a closed vessel where water or other fluid is heated. The liquid will not always boil. (In North America, the term "furnace" is generally used if the purpose is never to boil the liquid.) The warmed or vaporized fluid exits the boiler for use in various heating system or processes applications,[1 - [2 - including drinking water heating, central heating system, 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, of the austenitic types especially, is not used in wetted parts of boilers credited to corrosion and stress corrosion breaking.[3 - However, ferritic stainless steel is often used in superheater sections that will not come in contact with boiling water, and electrically heated stainless steel shell boilers are allowed under the European "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 because it is more fabricated in smaller size boilers easily. Historically, copper was often used for fireboxes (particularly for steam locomotives), because of its better formability and higher thermal conductivity; however, in newer times, the high price of copper often makes this an uneconomic choice and cheaper substitutes (such as metal) are used instead. For a lot of the Victorian "age of steam", the only material used for boilermaking was the best quality of wrought iron, with assembly by rivetting. This iron was from specialist ironworks, such as at Cleator Moor (UK), mentioned 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 relocated towards the utilization of steel instead, which is stronger and cheaper, with welded construction, which is quicker and requires less labour. It should be mentioned, 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 much superior to those of welded steel boilers. Cast iron can be utilized for the heating system vessel of domestic drinking water heaters. Although such heaters are usually termed "boilers" in a few countries, their purpose is to create hot water usually, not steam, and so they run at low pressure and try to avoid boiling. The brittleness of cast iron helps it be impractical for high-pressure vapor boilers. Boiler Repairs East Ham, Beckton, E6, Boiler Breakdown Emergency Service http://boiler-repairs-east-ham.co.uk - Click here>>> Energy The source of heat 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 system elements. Nuclear fission is also used as a heat source for generating steam, either directly (BWR) or, in most cases, in specialised high temperature exchangers called "vapor 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 Direct method -immediate approach to boiler efficiency test is more usable or more common boiler efficiency =Q*((Hg-Hf)/q)*(GCV *100 ) Q =Total vapor movement Hg= Enthalpy of saturated vapor in k cal/kg Hf =Enthalpy of feed drinking water in kcal/kg q= quantity of gasoline use in kg/hr GCV =gross calorific value in kcal/kg like family pet coke (8200 kcal/KG) indirect method -to measure the boiler efficiency in indirect method, we need a following parameter like Ultimate analysis of fuel (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 gas in kcal/kg ash percentage in combustible fuel GCV of ash in kcal/kg Configurations Boilers can be classified in to the following configurations: Container boiler or Haycock boiler/Haystack boiler: a primitive "kettle" where a fire heats a partially filled drinking water box from below. 18th century Haycock boilers generally produced and stored large amounts of very low-pressure steam, hardly above that of the atmosphere often. These could burn off wood or frequently, coal. Efficiency was suprisingly low. Flued boiler with a couple of large flues-an early forerunner or kind of fire-tube boiler. Diagram of the fire-tube boiler Fire-tube boiler: Here, water partially fills a boiler barrel with a small volume still left above to accommodate the steam (steam space). This is the type of boiler used in almost all steam locomotives. The heat source is inside a furnace or firebox that needs to be held permanently surrounded by water in order to keep up the temperatures of the heating system surface below the boiling point. The furnace can be situated at one end of a fire-tube which lengthens the road of the hot gases, thus augmenting the heating surface which can be further increased by making the gases invert direction through a second parallel tube or a lot of money of multiple pipes (two-pass or return flue boiler); alternatively the gases may be taken 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 lot of money of fire pipes inside the barrel which greatly increases the heating surface compared to a single tube and further enhances heat transfer. Fire-tube boilers will often have a comparatively low rate of steam creation, but high steam storage capacity. Fire-tube boilers mainly burn off solid fuels, but are easily adjustable to those of the liquid or gas variety. Diagram of a water-tube boiler. Water-tube boiler: In this kind, tubes filled up with drinking water are arranged in the furnace in a number of possible configurations. Often the drinking water tubes connect large drums, the lower ones containing water and top of the ones steam and water; in other situations, such as a mono-tube boiler, drinking water is circulated by a pump through a succession of coils. This kind provides high steam creation rates generally, but less storage capacity than the above. Water pipe boilers can be made to exploit any high temperature source and are generally preferred in high-pressure applications since the high-pressure water/vapor is included within small diameter pipes which can withstand the pressure with a thinner wall. Flash boiler: A flash boiler is a specialized kind of water-tube boiler where pipes are close jointly and drinking water is pumped through them. A flash boiler differs from the type of mono-tube vapor generator in which the tube is permanently filled with water. Super fast boiler, the tube is held so hot that water give food to is quickly flashed into vapor and superheated. Flash boilers had some use in cars in the 19th century which 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 both above types have been mixed in the next manner: the firebox contains an set up of water tubes, called thermic siphons. The gases go through a typical 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. In a solid iron sectional boiler, sometimes called a "pork chop boiler" water is included inside solid iron areas.[citation needed - These areas are assembled on site to produce the finished boiler. Safety See also: Boiler explosion To define and secure boilers safely, some professional specialized organizations like the American Culture of Mechanical Engineers (ASME) develop standards and regulation rules. For example, the ASME Boiler and Pressure Vessel Code is a standard providing an array of rules and directives to ensure compliance of the boilers and other pressure vessels with security, design and security standards.[5 - Historically, boilers were a source of many serious injuries and property destruction due to poorly 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 vapor it expands to over 1,000 times its original travels and volume down steam pipes at over 100 kilometres each hour. As a result of this, vapor is a superb way of moving energy and high temperature around a niche site from a central boiler house to where it is needed, but with no right boiler give food to water treatment, a steam-raising place will suffer from size formation and corrosion. At best, this raises energy costs and can result in poor quality vapor, reduced efficiency, shorter plant life and unreliable procedure. At worst, it can lead to catastrophic reduction and failing of life. Collapsed or dislodged boiler pipes can also aerosol scalding-hot steam and smoke out of the air intake and firing chute, injuring the firemen who load the coal in to the fire chamber. Extremely large boilers providing a huge selection of horsepower to use factories can potentially demolish entire buildings.[6 - A boiler that has a loss of give food to water and is permitted to boil dry out can be extremely dangerous. If supply drinking water is then sent in to the vacant boiler, the small cascade of inbound water instantly boils on contact with the superheated metal shell and leads to a violent explosion that can't be controlled even by protection steam valves. Draining of the boiler can also happen if a leak occurs in the steam supply lines that is larger than the make-up drinking water supply could replace. The Hartford Loop was invented in 1919 by the Hartford Steam Boiler and Insurance Company as a method to assist in preventing this problem from occurring, and therefore reduce their insurance promises.[7 - [8 - Superheated steam boiler A superheated boiler on the steam locomotive. Main article: Superheater Most boilers produce steam to be utilized at saturation heat; that is, saturated steam. Superheated steam boilers vaporize the water and further heat the steam in a superheater then. This provides steam at much higher temp, but can decrease the overall thermal efficiency of the steam generating plant because the higher vapor heat requires a higher flue gas exhaust heat.[citation needed - There are many ways to circumvent this problem, by giving an economizer that heats the feed drinking water typically, a combustion air heater in the hot flue gas exhaust path, or both. There are advantages to superheated steam that may, and often will, increase overall efficiency of both vapor generation and its utilization: benefits in input temperatures to a turbine should outweigh any cost in additional boiler complication and expense. There may also be useful restrictions in using damp vapor, as entrained condensation droplets will harm turbine blades. Superheated steam presents unique safety concerns because, if any operational system component fails and allows steam to escape, the temperature and pressure can cause serious, instantaneous injury to anyone in its path. Since the escaping steam will be completely superheated vapor, detection can be difficult, although the extreme heat and sound from such a leak indicates its presence clearly. Superheater operation is similar to that of the coils on an air conditioning unit, although for a different purpose. The steam piping is directed through the flue gas route 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 glowing type; that is, they absorb temperature by rays. Others are convection type, absorbing heat from a liquid. Some are a mixture of both types. Through either method, the extreme temperature in the flue gas route will also temperature the superheater steam piping and the steam within. While the heat of the steam in the superheater increases, the pressure of the vapor will not and the pressure remains the same as that of the boiler.[9 - Almost all steam superheater system designs remove droplets entrained in the steam to prevent harm to the turbine blading and associated piping. Supercritical steam generator Boiler for a power plant. Main article: Supercritical steam generator Supercritical steam generators are generally used for the production of energy. They operate at supercritical pressure. In contrast 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 that occurs; the liquid is neither liquid nor gas but a super-critical liquid. There is no era of steam bubbles within the water, because the pressure is above the critical pressure point of which vapor bubbles can develop. As the fluid expands through the turbine phases, its thermodynamic state drops below the critical point as it can work turning the turbine which changes the electrical generator from which power is eventually extracted. The liquid at that point may be considered a mix of vapor and liquid droplets as it passes in to the condenser. This leads to less fuel use and for that reason less greenhouse gas production slightly. The term "boiler" should not be used for a supercritical pressure vapor generator, as no "boiling" occurs in this product. Boiler Repairs East Ham, Beckton, E6, Boiler Breakdown Emergency Service http://boiler-repairs-east-ham.co.uk - Click here! Accessories Boiler accessories and fittings Pressuretrols to control the vapor pressure in the boiler. Boilers generally have two or three 3 pressuretrols: a manual-reset pressuretrol, which functions as a basic safety by setting the upper limit of steam pressure, the working pressuretrol, which handles when the boiler fires to maintain pressure, and for boilers equipped with a modulating burner, a modulating pressuretrol which settings the amount of fire. Basic safety valve: It is utilized to alleviate pressure and prevent possible explosion of the boiler. Water level signals: They show the operator the level of fluid in the boiler, known as a sight glass also, water measure 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 implies, this valve is located directly on the bottom of the boiler usually, and is sometimes opened to use the pressure in the boiler to push these particulates out. Continuous blowdown valve: This allows a small quantity of water to escape continuously. Its purpose is to prevent the water in the boiler becoming saturated with dissolved salts. Saturation would lead to foaming and cause drinking water droplets to be transported over with the steam - an ailment known as priming. Blowdown is also often used to monitor the chemistry of the boiler water. Trycock: a kind of valve that is often use to manually check a liquid level in a container. Mostly entirely on a water boiler. Flash tank: High-pressure blowdown enters this vessel where in fact the vapor can 'flash' safely and be used in a low-pressure system or be vented to atmosphere as the ambient pressure blowdown moves to drain. Automatic blowdown/continuous heat recovery system: This system allows the boiler to blowdown only when makeup water is flowing to the boiler, thereby transferring the utmost amount of heat possible from the blowdown to the makeup water. No flash tank is normally needed as the blowdown discharged is close to the temp of the make-up water. Hand holes: They may be metal plates installed in openings in "header" to allow for inspections & installing pipes and inspection of internal surfaces. Vapor drum internals, a series of screen, scrubber & cans (cyclone separators). Low-water cutoff: It really is a mechanical means (usually a float change) that can be used to turn from the burner or shut down fuel to the boiler to prevent it from running once the water moves below a certain point. If a boiler is "dry-fired" (burnt without drinking water in it) it can cause rupture or catastrophic failing. Surface blowdown series: It provides a means for removing foam or other light-weight non-condensible substances that tend to float on top of water inside the boiler. Circulating pump: It is designed to circulate drinking water back again to the boiler after it has expelled some of its heat. Feedwater check valve or clack valve: A non-return stop valve in the feedwater range. This can be installed to the side of the boiler, just below the water level, or to the very best of the boiler.[10 - Top feed: Within this design for feedwater injection, the water is fed to the very best of the boiler. This may reduce boiler exhaustion caused by thermal stress. By spraying the feedwater over some trays water is quickly heated and this can reduce limescale. Desuperheater tubes or bundles: A series of tubes or bundles of pipes in the water drum or the vapor drum designed to cool superheated steam, in order to supply auxiliary equipment that will not need, or may be damaged by, dry out steam. Chemical injection line: A connection to add chemicals for controlling feedwater pH. Steam accessories Main vapor stop valve: Steam traps: Main steam stop/check valve: It can be used on multiple boiler installations. Combustion accessories Energy oil system:fuel oil heaters Gas system: Coal system: Soot blower Other essential items Pressure gauges: Feed pumps: Fusible plug: Inspectors test pressure gauge attachment: Name plate: Registration dish:'