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A boiler is a closed vessel where water or other liquid is heated. The fluid does not necessarily boil. (In THE UNITED STATES, the word "furnace" is generally used if the reason is not to boil the fluid.) The heated or vaporized fluid exits the boiler for use in a variety of processes or heating system applications,[1 - [2 - including drinking 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 of wrought iron historically. Stainless steel, of the austenitic types especially, is not used in wetted elements of boilers due to corrosion and stress corrosion breaking.[3 - However, ferritic stainless is often used in superheater sections that will not come in contact with boiling water, and electrically heated stainless shell boilers are allowed under the Western "Pressure Equipment Directive" for creation 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), due to 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 group of steam", the only material used for boilermaking was the best quality of wrought iron, with assembly by rivetting. This iron was often obtained from specialist ironworks, such as at Cleator Moor (UK), noted for the high quality of their rolled plate and its own suitability for high-reliability use in critical applications, such as high-pressure boilers. In the 20th century, design practice instead transferred towards the utilization of metal, which is more powerful and cheaper, with welded building, which is quicker and requires less labour. It should be noted, however, that wrought iron boilers corrode far slower than their modern-day metal counterparts, and are less vunerable to localized stress-corrosion and pitting. This makes the longevity of old wrought-iron boilers significantly 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 produce hot water usually, not steam, and they also run at low pressure and stay away from boiling. The brittleness of cast iron makes it impractical for high-pressure steam boilers. Boiler Repairs Golders Green, Hampstead Garden Suburb, NW11, Boiler Breakdown Emergency Service http://boiler-repairs-golders-green.co.uk - Boiler Repairs Golders Green, Hampstead Garden Suburb, NW11, Boiler Breakdown Emergency Service! Energy The source of heating for a boiler is combustion of some of several fuels, such as wood, coal, oil, or natural gas. Electric vapor boilers use level of resistance- or immersion-type heating elements. Nuclear fission is utilized as a heat source for generating steam also, either straight (BWR) or, generally, in specialised heat exchangers called "vapor generators" (PWR). Heat recovery vapor generators (HRSGs) use the heat rejected from other processes such as gas turbine. Boiler efficiency there are two solutions to gauge the boiler efficiency 1) direct method 2) indirect method Direct method -direct approach to boiler efficiency test is more useful or even more common boiler efficiency =Q*((Hg-Hf)/q)*(GCV *100 ) Q =Total steam stream Hg= Enthalpy of saturated steam in k cal/kg Hf =Enthalpy of give food to drinking water in kcal/kg q= level of fuel use in kg/hr GCV =gross calorific value in kcal/kg like family pet coke (8200 kcal/KG) indirect method -to gauge the boiler efficiency in indirect method, we need a following parameter like Ultimate analysis of energy (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 gasoline 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 fireplace heats a partially filled drinking water container from below. 18th century Haycock boilers produced and stored large quantities of very low-pressure vapor generally, often barely above that of the atmosphere. These could burn 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 a fire-tube boiler Fire-tube boiler: Here, drinking water partially fills a boiler barrel with a small volume remaining above to support the steam (steam space). This is the kind of boiler used in nearly all steam locomotives. Heat source is in the furnace or firebox that has to be kept completely surrounded by the water in order to keep 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 path of the hot gases, thus augmenting the heating surface which may be further increased by making the gases reverse direction through a second parallel pipe or a lot of money of multiple pipes (two-pass or return flue boiler); additionally the gases may be taken along the edges and then beneath the boiler through flues (3-pass boiler). In case of a locomotive-type boiler, a boiler barrel expands from the firebox and the hot gases pass through a lot of money of fire pipes inside the barrel which greatly escalates the heating system surface in comparison to a single pipe and further enhances heat transfer. Fire-tube boilers usually have a comparatively low rate of vapor production, but high steam storage capacity. Fire-tube boilers mainly burn solid fuels, but are easily versatile to people of the liquid or gas variety. Diagram of the water-tube boiler. Water-tube boiler: In this type, pipes filled with drinking water are arranged inside a furnace in several possible configurations. Water tubes connect large drums Often, the low ones containing water and top of the ones water and steam; in other situations, like a mono-tube boiler, water is circulated with a pump through a succession of coils. This type gives high steam production rates generally, but less storage capacity than the above mentioned. Water tube boilers can be made to exploit any heat source and are generally preferred in high-pressure applications because the high-pressure water/vapor is contained within small diameter pipes which can withstand the pressure with a thinner wall structure. Flash boiler: A flash boiler is a specialized kind of water-tube boiler where pipes are close together and drinking water is pumped through them. A flash boiler differs from the kind of mono-tube steam generator where the pipe is permanently filled up with water. Super fast boiler, the pipe is held so hot that the water feed is quickly flashed into steam and superheated. Flash boilers had some use in cars in the 19th century which use continued into 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 combined in the following manner: the firebox contains an set up of water pipes, called thermic siphons. The gases pass through a typical firetube boiler then. Water-tube fireboxes were installed in many Hungarian locomotives,[citation needed - but have met with little success far away. Sectional boiler. Inside a solid iron sectional boiler, sometimes called a "pork chop boiler" water is included inside ensemble iron areas.[citation needed - These areas 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 Technical engineers (ASME) develop specifications and regulation codes. For example, the ASME Boiler and Pressure Vessel Code is a typical 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 way to obtain many serious injuries and property destruction as a consequence to poorly understood engineering principles. Thin and brittle steel shells can rupture, while poorly welded or riveted seams could start, leading to a violent eruption of the pressurized steam. When water is changed into vapor it expands to over 1,000 times its original quantity and moves down vapor pipes at over 100 kilometres each hour. Because of this, vapor is a superb way of moving energy and warmth around a site from a central boiler house to where it is necessary, but with no right boiler feed water treatment, a steam-raising herb are affected from size development and corrosion. At best, this raises energy costs and can lead to poor quality steam, reduced efficiency, shorter vegetation and unreliable procedure. At worst, it can result in catastrophic failing and loss of life. Collapsed or dislodged boiler tubes can also squirt scalding-hot steam and smoke from the air intake and firing chute, injuring the firemen who load the coal into the fire chamber. Extremely large boilers providing hundreds of horsepower to operate factories could demolish entire buildings.[6 - A boiler that has a loss of feed drinking water and is permitted to boil dry can be extremely dangerous. If supply water is then sent into the unfilled boiler, the tiny cascade of incoming water instantly boils on contact with the superheated metal shell and leads to a violent explosion that can't be controlled even by protection vapor valves. Draining of the boiler can also happen if a leak occurs in the steam source lines that is bigger than the make-up drinking water source could replace. The Hartford Loop was developed in 1919 by the Hartford Steam Boiler and INSURANCE PROVIDER as a strategy to help prevent this problem from happening, and thereby reduce their insurance promises.[7 - [8 - Superheated steam boiler A superheated boiler on the steam locomotive. Main article: Superheater Most boilers produce vapor to be utilized at saturation temperatures; that is, saturated steam. Superheated steam boilers vaporize the water and additional heating the steam in a superheater then. This provides vapor at much higher heat range, but can reduce the overall thermal efficiency of the steam generating plant because the bigger steam temperatures requires a higher flue gas exhaust heat.[citation needed - There are many ways to circumvent this problem, by providing an economizer that heats the feed water typically, a combustion air heater in the hot flue gas exhaust path, or both. There are benefits to superheated steam that may, and will often, increase overall efficiency of both steam generation and its utilization: increases in input heat range to a turbine should outweigh any cost in additional boiler problem and expense. There may also be practical limitations 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 flee, the high pressure and temperature 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 intense 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 vapor piping is directed through the flue gas route in the boiler furnace. The temperature in this area is between 1 typically,300 and 1,600 °C (2,372 and 2,912 °F). Some superheaters are glowing type; that is, they absorb heat by radiation. Others are convection type, absorbing heat from a fluid. Some are a mixture of both types. Through either method, the extreme high temperature in the flue gas path will also heat the superheater steam piping and the steam within. While the heat of the steam in the superheater goes up, the pressure of the vapor will not and the pressure remains the same as that of the boiler.[9 - Virtually all steam superheater system designs remove droplets entrained in the steam to avoid harm to the turbine blading and associated piping. Supercritical steam generator Boiler for a charged power vegetable. Main article: Supercritical steam generator Supercritical steam generators are used for the production of energy frequently. They operate at supercritical pressure. As opposed to a "subcritical boiler", a supercritical vapor generator operates at such a higher 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 generation of steam bubbles within water, because the pressure is above the critical pressure point at which steam bubbles can form. As the fluid expands through the turbine levels, its thermodynamic condition drops below the critical point as it can work turning the turbine which changes the electrical generator from which power is eventually extracted. The fluid at that point may be considered a mixture of steam and liquid droplets as it passes into the condenser. This leads to somewhat less gas use and for that reason less greenhouse gas production. The term "boiler" should not be used for a supercritical pressure steam generator, as no "boiling" occurs in this product. Boiler Repairs Golders Green, Hampstead Garden Suburb, NW11, Boiler Breakdown Emergency Service http://boiler-repairs-golders-green.co.uk - Show more! Accessories Boiler accessories and fittings Pressuretrols to regulate the steam 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 vapor pressure, the operating pressuretrol, which handles when the boiler fires to keep up pressure, as well as for boilers equipped with a modulating burner, a modulating pressuretrol which settings the amount of fire. Basic safety valve: It is utilized to relieve pressure and stop possible explosion of a boiler. Water level indicators: They show the operator the amount of fluid in the boiler, known as a sight glass also, water gauge or water column. Bottom level blowdown valves: They offer a means for removing solid particulates that condense and lie on the bottom of a boiler. As the name implies, this valve is usually located on underneath of the boiler, and is occasionally opened to use the pressure in the boiler to force these particulates out. Constant blowdown valve: This enables a small quantity of water to flee continuously. Its purpose is to avoid water in the boiler becoming saturated with dissolved salts. Saturation would business lead to foaming and cause water droplets to be carried over with the steam - an ailment known as priming. Blowdown is also often used to monitor the chemistry of the boiler drinking water. Trycock: a type of valve that is often use to manually check a water level in a tank. Most commonly found on a drinking water boiler. Flash tank: High-pressure blowdown enters this vessel where the steam can 'flash' safely and be found in a low-pressure system or be vented to atmosphere while the ambient pressure blowdown flows to drain. Automatic blowdown/constant heat recovery system: This technique 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 make-up water. No flash tank is generally needed as the blowdown discharged is close to the temp of the make-up water. Hand openings: These are steel plates installed in openings in "header" to permit for inspections & installing tubes and inspection of inner 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 is utilized to turn off the burner or shut down gas to the boiler to avoid it from working once the water goes 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 range: It provides a means for removing foam or other lightweight non-condensible substances that tend to float together with the water inside the boiler. Circulating pump: It really is designed to circulate 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 range. This may be installed to the side of the boiler, below water level just, or to the very best of the boiler.[10 - Top feed: In this design for feedwater injection, water is fed to the very best of the boiler. This may reduce boiler fatigue triggered by thermal stress. By spraying the feedwater over a series of trays the water is quickly warmed which can reduce limescale. Desuperheater tubes or bundles: A series of pipes or bundles of pipes in water drum or the vapor drum designed to cool superheated steam, in order to provide auxiliary equipment that does not need, or may be damaged by, dry vapor. Chemical injection line: A link with add chemicals for controlling feedwater pH. Steam accessories Main vapor stop valve: Steam traps: Main vapor stop/check valve: It is utilized on multiple boiler installations. Combustion accessories Fuel oil system:energy 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 dish: