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A boiler is a closed vessel where water or other fluid is heated. The fluid does not always boil. (In North America, the word "furnace" is normally used if the reason is not to boil the liquid.) The warmed or vaporized liquid exits the boiler for use in various procedures or heating applications,[1 - [2 - including water heating, central heating system, boiler-based power generation, food preparation, and sanitation. Materials The pressure vessel of a boiler is usually made of steel (or alloy steel), or of wrought iron historically. Stainless steel, of the austenitic types especially, is not used in wetted parts of boilers due to stress and corrosion corrosion cracking.[3 - However, ferritic stainless steel is often used in superheater sections that won't be exposed to boiling drinking water, and electrically heated stainless steel shell boilers are allowed under the European "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 easier fabricated in smaller size boilers. Historically, copper was often used for fireboxes (particularly for vapor 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 group of steam", the only materials used for boilermaking was the best grade of wrought iron, with set up by rivetting. This iron was often obtained from specialist ironworks, such as at Cleator Moor (UK), observed 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 transferred towards the use of steel instead, which is stronger and cheaper, with welded structure, which is quicker and requires less labour. It should be noted, however, that wrought iron boilers corrode considerably slower than their modern-day steel counterparts, and are less susceptible to localized stress-corrosion and pitting. This makes the longevity of old wrought-iron boilers far more advanced than those of welded steel boilers. Cast iron might be utilized for the heating vessel of home water heaters. Although such heaters are usually termed "boilers" in some countries, their purpose is to produce 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 Bethnal Green, Shoreditch, E2, Boiler Breakdown Emergency Service http://boiler-repairs-bethnal-green.co.uk - Show more>>> 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 level of resistance- or immersion-type heating system elements. Nuclear fission is also used as a heat source for producing steam, either straight (BWR) or, in most cases, in specialised temperature exchangers called "steam generators" (PWR). Warmth recovery vapor generators (HRSGs) use the heat rejected from other procedures such as gas turbine. Boiler efficiency there are two solutions to measure the boiler efficiency 1) direct method 2) indirect method Immediate method -immediate approach to boiler efficiency test is more functional or more common boiler efficiency =Q*((Hg-Hf)/q)*(GCV *100 ) Q =Total vapor flow 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 gauge the boiler efficiency in indirect method, we are in need of a subsequent parameter like Ultimate analysis of gasoline (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 water box from below. 18th century Haycock boilers produced and stored large quantities of very low-pressure steam generally, hardly above that of the atmosphere often. These could burn off wood or most often, 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, water partially fills a boiler barrel with a little volume still left above to accommodate the vapor (vapor space). This is the type of boiler used in all steam locomotives nearly. The heat source is inside a furnace or firebox that has to be held permanently surrounded by water in order to keep up the temp of the heating 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 surface which can be further increased by making the gases invert direction through a second parallel pipe or a bundle of multiple pipes (two-pass or return flue boiler); alternatively the gases may be studied along the sides and then beneath the boiler through flues (3-move boiler). In case of a locomotive-type boiler, a boiler barrel extends from the firebox and the hot gases go through a bundle of fire pipes inside the barrel which greatly escalates the heating system surface in comparison to a single pipe and further improves heat transfer. Fire-tube boilers will often have a comparatively low rate of steam creation, but high vapor storage capacity. Fire-tube boilers mainly burn off solid fuels, but are readily adaptable to those of the gas or liquid variety. Diagram of a water-tube boiler. Water-tube boiler: In this type, pipes filled up with water are arranged inside a furnace in a true quantity of possible configurations. Water tubes connect large drums Often, the low 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 steam creation rates, but less storage capacity than the above mentioned. Water pipe boilers can be made to exploit any temperature source and are generally preferred in high-pressure applications because the high-pressure drinking water/vapor is included within small size pipes which can withstand the pressure with a thinner wall. Flash boiler: A flash boiler is a specialized type of water-tube boiler where pipes are close collectively and drinking water is pumped through them. A flash boiler differs from the kind of mono-tube vapor generator where the tube is permanently filled with water. Super fast boiler, the pipe is kept so hot that the water feed is quickly flashed into steam and superheated. Flash boilers had some use in automobiles in the 19th century and this use continued into the early 20th century. . 1950s design steam locomotive boiler, from a Victorian Railways J class Fire-tube boiler with Water-tube firebox. Sometimes both above types have been mixed in the following manner: the firebox contains an assembly of water tubes, called thermic siphons. The gases then go through a conventional firetube boiler. Water-tube fireboxes were installed in many Hungarian locomotives,[citation needed - but have met with little success far away. Sectional boiler. In a solid iron sectional boiler, sometimes called a "pork chop boiler" water is contained inside ensemble iron areas.[citation needed - These areas are assembled on site to generate the finished boiler. Safety See also: Boiler explosion To define and secure boilers safely, some professional specialized organizations such as the American Society of Mechanical Technical engineers (ASME) develop requirements and regulation codes. For example, the ASME Boiler and Pressure Vessel Code is a typical providing an array of guidelines and directives to ensure compliance of the boilers and other pressure vessels with protection, security and design standards.[5 - Historically, boilers were a way to obtain many serious injuries and property destruction as a consequence 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 steam. When water is converted to steam it expands to over 1,000 times its original travels and volume down steam pipes at over 100 kilometres per hour. Because of this, steam is a superb way of moving energy and heat around a niche site from a central boiler house to where it is necessary, but without the right boiler feed water treatment, a steam-raising herb are affected from level development and corrosion. At best, this boosts energy costs and can lead to poor quality vapor, reduced efficiency, shorter plant life and unreliable operation. At worst, it can lead to catastrophic failure and loss of life. Collapsed or dislodged boiler tubes can also aerosol scalding-hot vapor and smoke from the air intake and firing chute, injuring the firemen who fill the coal into the open fire chamber. Extremely large boilers providing hundreds of horsepower to operate factories could demolish entire buildings.[6 - A boiler that has a loss of give food to drinking water and it is permitted to boil dry out can be extremely dangerous. If feed water is sent in to the clear boiler then, the tiny cascade of inbound water instantly boils on contact with the superheated metallic shell and leads to a violent explosion that cannot be controlled even by protection 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 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 condition from happening, and thus reduce their insurance statements.[7 - [8 - Superheated steam boiler A superheated boiler on the steam locomotive. Main article: Superheater Most boilers produce vapor to be used at saturation temp; that is, saturated vapor. Superheated steam boilers vaporize water and further heat up the steam in a superheater then. This provides vapor at higher heat, but can decrease the overall thermal efficiency of the vapor generating herb because the higher vapor heat range requires a higher flue gas exhaust temp.[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 path, or both. A couple of advantages to superheated steam that may, and often will, increase overall efficiency of both steam generation and its utilization: increases in input temp to a turbine should outweigh any cost in additional boiler complication and expense. There can also be useful limitations in using damp steam, 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 at first be completely superheated vapor, detection can be difficult, although the extreme heat and sound from such a leak clearly indicates its presence. 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 heat range in this area is normally between 1,300 and 1,600 °C (2,372 and 2,912 °F). Some superheaters are radiant type; that is, they absorb warmth by radiation. Others are convection type, absorbing heat 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 temperature of the steam in the superheater goes up, the pressure of the vapor will not and the pressure remains exactly like that of the boiler.[9 - Virtually 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 vegetable. Main article: Supercritical steam generator Supercritical steam generators are frequently used for the production of electric power. They operate at supercritical pressure. In contrast to a "subcritical boiler", a supercritical steam 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 era of vapor bubbles within water, because the pressure is above the critical pressure point at which vapor bubbles can form. As the liquid expands through the turbine levels, its thermodynamic state drops below the critical point as it can work turning the turbine which converts the electrical generator that power is ultimately extracted. The liquid at that time may be a mix of steam and liquid droplets as it goes by in to the condenser. This leads to less fuel use and therefore less greenhouse gas production slightly. The term "boiler" shouldn't be used for a supercritical pressure steam generator, as no "boiling" occurs in this product. Boiler Repairs Bethnal Green, Shoreditch, E2, Boiler Breakdown Emergency Service http://boiler-repairs-bethnal-green.co.uk - Show more! Accessories Boiler accessories and fittings Pressuretrols to control the vapor pressure in the boiler. Boilers generally have 2 or 3 3 pressuretrols: a manual-reset pressuretrol, which functions as a protection by setting the top limit of steam pressure, the operating pressuretrol, which settings when the boiler fires to keep pressure, and for boilers equipped with a modulating burner, a modulating pressuretrol which settings the quantity of fire. Protection valve: It can be used to relieve pressure and stop possible explosion of a boiler. Water level indications: They show the operator the amount of fluid in the boiler, also known as a sight glass, water gauge or water column. Bottom blowdown valves: They offer a means for removing solid particulates that condense and rest on the bottom of the boiler. As the name suggests, this valve is usually located on underneath of the boiler, and is sometimes opened to use the pressure in the boiler to drive these particulates out. Continuous blowdown valve: This enables a small quantity of water to flee continuously. Its purpose is to avoid the water in the boiler becoming saturated with dissolved salts. Saturation would business lead to foaming and cause drinking water droplets to be carried over with the vapor - a disorder known as priming. Blowdown is often used to monitor the chemistry of the boiler drinking water also. Trycock: a kind of valve that is often use to manually check a water level in a tank. Most commonly entirely on a 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/continuous heat recovery system: This technique allows the boiler to blowdown only when make-up water is moving to the boiler, thereby transferring the maximum amount of heat possible from the blowdown to the makeup water. No flash tank is generally needed as the blowdown discharged is close to the temperatures of the make-up water. Hand openings: These are metal plates installed in openings in "header" to allow for inspections & installing pipes and inspection of internal surfaces. Steam drum internals, some display screen, scrubber & cans (cyclone separators). Low-water cutoff: It really is a mechanical means (usually a float switch) that can be used to turn from the burner or shut off gas to the boiler to avoid it from working once the water runs below a certain point. If a boiler is "dry-fired" (burned without water in it) it can cause rupture or catastrophic failure. Surface blowdown line: It offers a way for removing foam or other lightweight non-condensible substances that have a tendency to float together with water inside the boiler. Circulating pump: It really is designed to circulate water back 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 line. This may be suited to the relative aspect of the boiler, below 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 triggered by thermal stress. By spraying the feedwater over some trays water is quickly heated and this can reduce limescale. Desuperheater pipes or bundles: A series of pipes or bundles of pipes in the water drum or the vapor drum designed to cool superheated steam, in order to supply auxiliary equipment that does not need, or may be damaged by, dry out vapor. Chemical substance injection line: A link with add chemicals for controlling feedwater pH. Steam accessories Main steam stop valve: Steam traps: Main vapor stop/check valve: It is used on multiple boiler installations. Combustion accessories Gasoline 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 dish: Registration plate:

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