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1:まお :

2017/09/13 (Wed) 15:34:59

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女の子が教える完全無料出会い系サイトを紹介!!ハルカの一言アドバイス付きです。メル友、恋人からセフレ、エッチな人妻まで、すべて無料だから出会い放題。
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2:JamesWer:

2017/09/13 (Wed) 15:37:48

A boiler is a closed vessel where water or other fluid is heated. The liquid does not always boil. (In THE UNITED STATES, the term "furnace" is generally used if the purpose is not to boil the fluid.) The heated or vaporized liquid exits the boiler for use in a variety of processes or heating applications,[1][2] including water heating, central heating system, boiler-based power era, cooking food, 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 thanks to stress and corrosion corrosion breaking.[3] However, ferritic stainless steel is often found in superheater sections that will not be exposed to boiling water, and electrically heated stainless shell boilers are allowed under the Western 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 (particularly 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 metal) are used instead.

For much of the Victorian "age of vapor", the only materials used for boilermaking was the best quality of wrought iron, with set up 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 own suitability for high-reliability use in critical applications, such as high-pressure boilers. In the 20th century, design practice transferred towards the utilization of steel instead, which is stronger and cheaper, with welded structure, which is quicker and requires less labour. It ought to be noted, however, that wrought iron boilers corrode significantly slower than their modern-day steel counterparts, and are less susceptible to localized stress-corrosion and pitting. This makes the durability of old wrought-iron boilers much more advanced than those of welded metal boilers.

Cast iron might be used for the heating vessel of home water heaters. Although such heaters are usually termed "boilers" in some countries, their purpose is usually to produce warm water, 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 vapor boilers.
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Energy
The foundation of heat for a boiler is combustion of some of several fuels, such as wood, coal, oil, or natural gas. Electric steam boilers use resistance- or immersion-type heating elements. Nuclear fission is used as a heat source for generating steam also, either straight (BWR) or, generally, in specialised high temperature exchangers called "steam generators" (PWR). Temperature recovery steam 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 method of boiler efficiency test is more functional or even more common

boiler efficiency =Q*((Hg-Hf)/q)*(GCV *100 ) Q =Total vapor stream Hg= Enthalpy of saturated vapor in k cal/kg Hf =Enthalpy of feed water in kcal/kg q= level 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 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 gasoline in kcal/kg
ash percentage in combustible fuel
GCV of ash in kcal/kg
Configurations
Boilers can be classified into the following configurations:

Pot boiler or Haycock boiler/Haystack boiler: a primitive "kettle" in which a fireplace heats a partially filled water pot from below. 18th century Haycock boilers produced and stored large amounts of very low-pressure steam generally, hardly above that of the atmosphere often. These could burn wood or frequently, coal. Efficiency was suprisingly low.
Flued boiler with a couple of 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 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 in the furnace or firebox that needs to be held permanently surrounded by water in order to keep up the heat of the heating 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 causing the gases reverse direction through another parallel tube or a bundle of multiple tubes (two-pass or come back flue boiler); on the other hand the gases may be studied along the edges and then under 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 bundle of fire pipes inside the barrel which greatly escalates the heating surface compared to a single pipe and further improves heat transfer. Fire-tube boilers have a comparatively low rate of vapor creation usually, but high steam storage capacity. Fire-tube boilers mainly burn solid fuels, but are easily adjustable to the people of the liquid or gas variety.

Diagram of a water-tube boiler.
Water-tube boiler: In this kind, pipes filled up with water are arranged in the furnace in a genuine variety of possible configurations. Often the drinking water tubes connect large drums, the low ones containing water and top of the ones water and steam; in other cases, like a mono-tube boiler, water is circulated by a pump through a succession of coils. This kind generally provides high vapor creation rates, but less storage capacity than the above mentioned. Water pipe boilers can be made to exploit any warmth source and tend to be preferred in high-pressure applications since the high-pressure water/steam is contained within small diameter pipes which can withstand the pressure with a thinner wall.
Flash boiler: A flash boiler is a specialized type of water-tube boiler in which pipes are close collectively and drinking water is pumped through them. A flash boiler differs from the type of mono-tube vapor generator where the pipe is permanently filled up with water. In a flash boiler, the pipe is kept so hot that water feed is quickly flashed into steam and superheated. Flash boilers experienced 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 the two above types have been mixed in the next manner: the firebox consists of an assembly of water pipes, called thermic siphons. The gases then pass 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 cast iron sectional boiler, sometimes called a "pork chop boiler" the water is included inside solid iron areas.[citation needed] These sections are assembled on site to produce the finished boiler.
Safety
See also: Boiler explosion
To define and secure boilers safely, some professional specialized organizations such as the American Culture of Mechanical Technical engineers (ASME) develop standards and regulation codes. 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 safety, 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 metallic 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 steam it expands to over 1,000 times its original quantity and travels down vapor pipes at over 100 kilometres per hour. Because of this, vapor is a superb way of moving energy and heat around a site from a central boiler house to where it is needed, but without the right boiler feed water treatment, a steam-raising flower are affected from size formation and corrosion. At best, this raises energy costs and can result in poor quality steam, reduced efficiency, shorter plant life and unreliable operation. At worst, it can lead to catastrophic failure and lack of life. Collapsed or dislodged boiler tubes can also squirt scalding-hot steam and smoke out of the air intake and firing chute, injuring the firemen who load the coal in to the fireplace chamber. Extremely large boilers providing a huge selection of horsepower to use factories can potentially demolish entire structures.[6]

A boiler that has a loss of feed water and is permitted to boil dry can be hugely dangerous. If give food to drinking water is then sent in to the bare boiler, the tiny cascade of incoming drinking water instantly boils on contact with the superheated metallic shell and leads to a violent explosion that can't be managed even by 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 Company as a method to help prevent this problem from happening, and thus reduce their insurance claims.[7][8]

Superheated steam boiler

A superheated boiler on a steam locomotive.
Main article: Superheater
Most boilers produce steam to be used at saturation heat range; that is, saturated vapor. Superheated steam boilers vaporize the water and then further temperature the steam in a superheater. This provides steam at higher temp, but can reduce the overall thermal efficiency of the steam generating plant because the higher steam temperature takes a higher flue gas exhaust temperatures.[citation needed] There are several ways to circumvent this issue, typically by giving an economizer that heats the feed water, a combustion air heating unit in the hot flue gas exhaust path, or both. A couple of advantages to superheated steam that may, and will often, increase overall efficiency of both vapor generation and its own utilization: increases in input heat range to a turbine should outweigh any cost in additional boiler complication and expense. There could be useful limitations in using moist vapor also, as entrained condensation droplets will damage turbine blades.

Superheated steam presents unique safety concerns because, if any operational system component fails and allows steam to flee, the ruthless 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 extreme heat and sound from such a leak indicates its existence clearly.

Superheater operation is similar to that of the coils on an fresh air conditioning unit, although for a different purpose. The steam piping is directed through the flue gas path in the boiler furnace. The heat in this field is between 1 typically,300 and 1,600 °C (2,372 and 2,912 °F). Some superheaters are glowing type; that is, they absorb warmth by radiation. Others are convection type, absorbing warmth from a fluid. Some are a combination 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 temperature 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] Virtually 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 electric power. They operate at supercritical pressure. As opposed 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 water nor gas but a super-critical liquid. 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 stages, its thermodynamic condition drops below the critical point as it does work turning the turbine which changes the power generator from which power is eventually extracted. The liquid at that point may be a mix of vapor and liquid droplets as it passes into the condenser. This leads to less fuel use and therefore 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.
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Accessories
Boiler accessories and fittings
Pressuretrols to regulate 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 top of the limit of steam pressure, the operating pressuretrol, which settings when the boiler fires to keep up pressure, and for boilers equipped with a modulating burner, a modulating pressuretrol which handles the amount of fire.
Protection valve: It is utilized to relieve pressure and prevent possible explosion of a boiler.
Water level indicators: They show the operator the amount of fluid in the boiler, known as a view cup also, water gauge or drinking water column.
Bottom level blowdown valves: They provide a means for removing solid particulates that condense and rest on the bottom of the boiler. As the name indicates, this valve is located straight on the bottom of the boiler usually, and is sometimes opened up to use the pressure in the boiler to push these particulates out.
Continuous blowdown valve: This enables a small level of water to escape continuously. Its purpose is to prevent 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 - an ailment 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 water level in a container. Most found on a water boiler commonly.
Flash tank: High-pressure blowdown enters this vessel where in fact the steam can 'flash' safely and become found 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 technique allows the boiler to blowdown only once 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 normally needed as the blowdown discharged is near to the heat of the make-up water.
Hand openings: These are metal plates installed in openings in "header" to permit for inspections & installing pipes and inspection of inner surfaces.
Steam drum internals, some display screen, scrubber & cans (cyclone separators).
Low-water cutoff: It is a mechanical means (usually a float change) that can be used to turn off the burner or shut down fuel to the boiler to prevent it from jogging once the drinking water goes below a certain point. If a boiler is "dry-fired" (burnt without drinking water in it) it can cause rupture or catastrophic failure.
Surface blowdown series: It provides 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 made to circulate water back again to the boiler after it has expelled a few of its heat.
Feedwater check valve or clack valve: A non-return stop valve in the feedwater collection. This may be installed to the side of the boiler, just below 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 triggered by thermal stress. By spraying the feedwater over a series of trays the water is quickly heated which can reduce limescale.
Desuperheater pipes or bundles: A series of tubes or bundles of tubes in the water drum or the vapor drum made to cool superheated vapor, in order to provide auxiliary equipment that does 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 steam stop valve:
Steam traps:
Main steam stop/check valve: It is utilized on multiple boiler installations.
Combustion accessories
Energy 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:

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