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A boiler is a closed vessel where drinking water or other fluid is heated. The fluid does not boil. (In North America, the word "furnace" is generally used if the reason is never to boil the liquid.) The warmed or vaporized fluid exits the boiler for use in a variety of heating or processes applications,[1][2] including water heating, central heating system, boiler-based power era, cooking food, and sanitation. Materials The pressure vessel of the boiler is usually manufactured from steel (or alloy steel), or of wrought iron historically. 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 steel is often found in superheater sections that will not come in contact with boiling water, and electrically heated stainless shell boilers are allowed under the European "Pressure Equipment Directive" for production of steam for sterilizers and disinfectors.[4] [url=https://en.wikipedia.org/wiki/Boiler]https://en.wikipedia.org/wiki/Boiler[/url] In live steam models, copper or brass is often used since it is more fabricated in smaller size boilers easily. Historically, copper was often used for fireboxes (especially for steam 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 metal) are used instead. For a lot of the Victorian "age group of steam", the only material used for boilermaking was the best grade of wrought iron, with assembly by rivetting. This iron was extracted 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 transferred towards the utilization of metal instead, which is stronger and cheaper, with welded building, which is quicker and requires less labour. It should be noted, however, that wrought iron boilers corrode much slower than their modern-day metal counterparts, and are less vunerable to localized stress-corrosion and pitting. This makes the longevity of older wrought-iron boilers significantly superior to those of welded steel boilers. Cast iron may be used for the heating system vessel of home drinking water heaters. Although such heaters are usually termed "boilers" in some countries, their purpose is to create warm water usually, not steam, and they also run at low pressure and try to avoid boiling. The brittleness of cast iron makes it impractical for high-pressure steam boilers. Boiler Repairs Abbey Wood, SE2, Boiler Breakdown Emergency Service [url=http://boiler-repairs-abbey-wood.co.uk]Boiler Repairs Abbey Wood, SE2, Boiler Breakdown Emergency Service![/url] Energy The source of heat for a boiler is combustion of any of several fuels, such as wood, coal, oil, or natural gas. Electric vapor boilers use resistance- or immersion-type heating system elements. Nuclear fission is also used as a heat source for generating steam, either straight (BWR) or, generally, in specialised warmth exchangers called "steam generators" (PWR). Warmth recovery steam generators (HRSGs) use the heat rejected from other procedures such as gas turbine. Boiler efficiency there are two methods to measure the boiler efficiency 1) direct method 2) indirect method Direct method -immediate method of boiler efficiency test is more usable or more common boiler efficiency =Q*((Hg-Hf)/q)*(GCV *100 ) Q =Total steam circulation Hg= Enthalpy of saturated vapor in k cal/kg Hf =Enthalpy of feed drinking water in kcal/kg q= quantity of fuel use in kg/hr GCV =gross calorific value in kcal/kg like pet coke (8200 kcal/KG) indirect method -to gauge the boiler efficiency in indirect method, we are in need of a subsequent 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: Pot boiler or Haycock boiler/Haystack boiler: a primitive "kettle" in which a open fire heats a partially filled drinking water container from below. 18th century Haycock boilers generally produced and stored large amounts of very low-pressure vapor, often hardly above that of the atmosphere. These could burn off wood or frequently, coal. Efficiency was suprisingly low. Flued boiler with one or two large flues-an early type or forerunner of fire-tube boiler. Diagram of the fire-tube boiler Fire-tube boiler: Here, drinking water partially fills a boiler barrel with a small volume left above to accommodate the vapor (steam space). This is the kind of boiler used in nearly all steam locomotives. Heat source is inside a furnace or firebox that needs to be kept permanently surrounded by the water in order to keep the heat of the heating system surface below the boiling point. The furnace can be situated at one end of the fire-tube which lengthens the path of the hot gases, thus augmenting the heating system surface which can be further increased by causing the gases invert direction through a second parallel tube 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 there is a locomotive-type boiler, a boiler barrel expands from the firebox and the hot gases pass through a bundle of fire tubes inside the barrel which greatly escalates the heating system surface compared to a single tube and further enhances heat transfer. Fire-tube boilers usually have a comparatively low rate of steam production, but high steam storage capacity. Fire-tube boilers mostly burn solid fuels, but are easily adjustable to those of the liquid or gas variety. Diagram of the water-tube boiler. Water-tube boiler: In this kind, pipes filled with water are arranged in the furnace in a genuine variety of possible configurations. Usually the drinking water pipes connect large drums, the lower ones formulated with drinking water and top of the ones vapor and drinking water; in other instances, such as 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 space capacity than the above mentioned. Water tube boilers can be made to exploit any warmth 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 kind of water-tube boiler in which tubes are close together and water is pumped through them. A flash boiler differs from the type of mono-tube steam generator where the tube is permanently filled up with water. In a flash boiler, the tube is kept so hot that the water feed is quickly flashed into steam and superheated. Flash boilers acquired some use in automobiles in the 19th century and this 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 the two above types have been combined in the next manner: the firebox includes an set up of water pipes, called thermic siphons. The gases then go through a typical firetube boiler. Water-tube fireboxes were installed in many Hungarian locomotives,[citation needed] but have fulfilled with little success in other countries. Sectional boiler. Inside a solid iron sectional boiler, sometimes called a "pork chop boiler" the water is included inside solid iron sections.[citation needed] These sections are assembled on site to make the finished boiler. Safety See also: Boiler explosion To define and secure boilers safely, some professional specialized organizations like the American Culture of Mechanical Designers (ASME) develop standards and regulation rules. For instance, the ASME Boiler and Pressure Vessel Code is a standard providing a wide range of rules and directives to ensure compliance of the boilers and other pressure vessels with safety, design and security standards.[5] Historically, boilers were a source of 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, resulting in a violent eruption of the pressurized steam. When drinking water is converted to vapor it expands to over 1,000 times its original quantity and moves down steam pipes at over 100 kilometres per hour. Because of this, vapor is a great 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 feed water treatment, a steam-raising vegetable will suffer from size development and corrosion. At best, this increases energy costs and can result in poor quality vapor, reduced efficiency, shorter plant life and unreliable procedure. At worst, it can result in catastrophic loss and failing of life. Collapsed or dislodged boiler pipes 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 structures.[6] A boiler which has a loss of give food to water and is permitted to boil dry out can be extremely dangerous. If give food to drinking water is then sent in to the vacant boiler, the small cascade of incoming drinking water instantly boils on contact with the superheated metallic shell and leads to a violent explosion that cannot be managed even by safety steam valves. Draining of the boiler can also happen if a leak occurs in the steam source lines that is larger than the make-up drinking water source could replace. The Hartford Loop was invented in 1919 by the Hartford Steam Boiler and Insurance Company as a strategy to assist in preventing this problem from taking place, and thereby 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 range; that is, saturated steam. Superheated steam boilers vaporize water and then further temperature the steam in a superheater. This provides vapor at higher heat range, but can decrease the overall thermal efficiency of the steam generating place because the bigger vapor temperature takes a higher flue gas exhaust heat range.[citation needed] There are several ways to circumvent this issue, typically by giving an economizer that heats the give food to drinking water, a combustion air heater in the hot flue gas exhaust route, or both. There are advantages to superheated vapor that may, and often will, increase overall efficiency of both vapor generation and its own utilization: gains in input temperature to a turbine should outweigh any cost in additional boiler complication and expense. There can also be practical restrictions in using moist steam, as entrained condensation droplets will damage turbine blades. Superheated steam presents unique safety concerns because, if any 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 at first be completely superheated vapor, detection can be difficult, although the intense heat and sound from such a leak indicates its existence clearly. Superheater procedure is similar to that of the coils on an fresh air conditioning unit, although for a different purpose. The vapor piping is directed through the flue gas route in the boiler furnace. The heat range in this field is normally between 1,300 and 1,600 °C (2,372 and 2,912 °F). Some superheaters are radiant type; that is, they absorb heat by rays. Others are convection type, absorbing warmth from a fluid. Some are a combination of the two 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 goes up, the pressure of the steam 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 harm to the turbine blading and associated piping. Supercritical steam generator Boiler for a charged power place. 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 that occurs; the fluid is liquid nor gas but a super-critical fluid neither. There is absolutely no generation of vapor bubbles within the water, because the pressure is above the critical pressure point at which steam bubbles can develop. As the fluid expands through the turbine levels, 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 fluid at that time may be considered a mix of steam and liquid droplets as it goes by in to the condenser. This results in slightly less energy use and for that reason less greenhouse gas production. The term "boiler" should not be used for a supercritical pressure vapor generator, as no "boiling" occurs in this product. Boiler Repairs Abbey Wood, SE2, Boiler Breakdown Emergency Service [url=http://boiler-repairs-abbey-wood.co.uk]Show more...[/url] Accessories Boiler accessories and fittings 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 upper limit of steam pressure, the working pressuretrol, which controls when the boiler fires to keep up pressure, as well as for boilers outfitted with a modulating burner, a modulating pressuretrol which settings the amount of fire. Security valve: It is used to relieve pressure and prevent possible explosion of a boiler. Water level indications: They show the operator the amount of liquid in the boiler, known as a sight cup also, water gauge or water column. Bottom blowdown valves: They offer a way for removing solid particulates that condense and lay on underneath of the boiler. As the name indicates, this valve is situated directly on the bottom of the boiler usually, and is occasionally opened to use the pressure in the boiler to force 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 carried over with the steam - an ailment known as priming. Blowdown is often used to monitor the chemistry of the boiler drinking water also. Trycock: a type of valve that is often use to manually check a water level in a container. Most commonly entirely on a water boiler. Flash tank: High-pressure blowdown enters this vessel where in fact the vapor can 'flash' safely and become found in a low-pressure system or be vented to atmosphere while the ambient pressure blowdown flows to drain. Automatic blowdown/continuous 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 makeup water. No flash container is generally needed as the blowdown discharged is near to the temp of the make-up water. Hand holes: 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 screen, scrubber & cans (cyclone separators). Low-water cutoff: It really is a mechanical means (usually a float change) that is used to turn from the burner or shut down gas to the boiler to prevent it from jogging once the drinking water runs below a certain point. If a boiler is "dry-fired" (burnt without water in it) it can cause rupture or catastrophic failing. Surface blowdown collection: It provides a way for removing foam or other light-weight non-condensible substances that tend to float together with water inside the boiler. Circulating pump: It really is made to circulate water back again to the boiler after they have expelled some of its heat. Feedwater check valve or clack valve: A non-return stop valve in the feedwater series. This may be fitted to the relative aspect of the boiler, below the water level just, or to the top of the boiler.[10] Top give food to: With this design for feedwater injection, the water is fed to the top of the boiler. This can reduce boiler fatigue caused by thermal stress. By spraying the feedwater over some trays water is quickly warmed which can reduce limescale. Desuperheater pipes or bundles: A series of pipes or bundles of pipes in the water drum or the vapor drum made to cool superheated steam, in order to provide auxiliary equipment that does not need, or may be damaged by, dry steam. 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 used on multiple boiler installations. Combustion accessories Fuel 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 dish: Registration dish:

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