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Boiler Repairs Catford, SE6, Boiler Breakdown Emergency Service

A boiler is a closed vessel where drinking water or other fluid is heated. The fluid will not always boil. (In North America, the term "furnace" is normally used if the reason is not to boil the fluid.) The warmed or vaporized liquid exits the boiler for use in various procedures or heating applications,[1][2] including drinking water heating, central heating, boiler-based power era, cooking, 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 found in wetted parts of boilers due to stress and corrosion corrosion breaking.[3] However, ferritic stainless is often found in superheater sections that won't be exposed to boiling 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]
[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 steel) are used instead.

For much of the Victorian "age group of vapor", the only material used for boilermaking was the best grade of wrought iron, with set up by rivetting. This iron was obtained from specialist ironworks, such as at Cleator Moor (UK), observed 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 shifted towards the use of metal instead, which is more powerful and cheaper, with welded construction, which is quicker and requires less labour. It ought to be observed, however, that wrought iron boilers corrode significantly slower than their modern-day steel counterparts, and are less susceptible to localized pitting and stress-corrosion. This makes the durability of older wrought-iron boilers far superior to those of welded steel boilers.

Cast iron can be utilized for the heating system vessel of domestic water heaters. Although such heaters are usually termed "boilers" in some countries, their purpose will be to produce hot 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 gas. Electric vapor boilers use resistance- or immersion-type heating elements. Nuclear fission is also used as a heat source for producing steam, either directly (BWR) or, in most cases, in specialised high temperature exchangers called "steam generators" (PWR). Temperature recovery vapor generators (HRSGs) use the heat rejected from other processes such as gas turbine.

Boiler efficiency
there are two methods to measure the boiler efficiency 1) direct method 2) indirect method

Immediate method -immediate method of boiler efficiency test is more usable or even more common

boiler efficiency =Q*((Hg-Hf)/q)*(GCV *100 ) Q =Total steam flow Hg= Enthalpy of saturated vapor in k cal/kg Hf =Enthalpy of feed drinking water in kcal/kg q= level of gasoline use in kg/hr GCV =gross calorific value in kcal/kg like pet coke (8200 kcal/KG)

indirect method -to measure the boiler efficiency in indirect method, we are in need of 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 into the following configurations:

Container boiler or Haycock boiler/Haystack boiler: a primitive "kettle" in which a fireplace heats a partially filled drinking water pot from below. 18th century Haycock boilers produced and stored large amounts of very low-pressure steam generally, barely above that of the atmosphere often. These could burn off wood or frequently, coal. Efficiency was suprisingly low.
Flued boiler with one or two large flues-an early forerunner or kind of fire-tube boiler.

Diagram of the fire-tube boiler
Fire-tube boiler: Here, drinking water partially fills a boiler barrel with a little volume still left above to accommodate the vapor (vapor space). This is the kind of boiler used in all steam locomotives nearly. Heat source is inside a furnace or firebox that has to be held permanently surrounded by water in order to maintain the temp 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 system surface which may be further increased by causing the gases invert direction through another parallel tube or a bundle of multiple tubes (two-pass or come back flue boiler); alternatively the gases may be studied along the edges and then beneath the boiler through flues (3-move boiler). In case there is a locomotive-type boiler, a boiler barrel stretches from the firebox and the hot gases go through a lot of money of fire pipes inside the barrel which greatly increases the heating system surface compared to a single tube and further boosts heat transfer. Fire-tube boilers usually have a comparatively low rate of vapor creation, but high steam storage capacity. Fire-tube boilers mainly burn solid fuels, but are readily adaptable 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 inside a furnace in several possible configurations. Often the drinking water pipes connect large drums, the low ones filled with drinking water and the upper ones vapor and drinking water; in other situations, like a mono-tube boiler, drinking water is circulated with a pump through a succession of coils. This type generally provides high steam production rates, but less storage capacity than the above. Water pipe boilers can be designed 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 tubes are close together and 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. In a flash boiler, the pipe is held so hot that the water feed is quickly flashed into vapor and superheated. Flash boilers experienced some use in automobiles in the 19th century which 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 combined in the following manner: the firebox includes an assembly 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 ensemble 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 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 guidelines and directives to ensure compliance of the boilers and other pressure vessels with protection, design and security standards.[5]

Historically, boilers were a source of many serious injuries and property destruction as a consequence to badly understood engineering principles. Thin and brittle steel shells can rupture, while welded or riveted seams could start poorly, resulting in a violent eruption of the pressurized vapor. When drinking water is converted to vapor it expands to over 1,000 times its original travels and volume down steam pipes at over 100 kilometres per hour. Because of this, vapor is a great way of moving energy and temperature around a niche site from a central boiler house to where it is needed, but without the right boiler feed water treatment, a steam-raising vegetable are affected from level formation and corrosion. At best, this increases energy costs and can lead to poor quality vapor, reduced efficiency, shorter plant life and unreliable procedure. At worst, it can lead to catastrophic failure and lack of life. Collapsed or dislodged boiler pipes can also squirt scalding-hot steam and smoke out of the air intake and firing chute, injuring the firemen who weight the coal into the fire chamber. Extremely large boilers providing a huge selection of horsepower to use factories can potentially demolish entire structures.[6]

A boiler which has a loss of feed water and is permitted to boil dry out can be hugely dangerous. If feed drinking water is then sent in to the vacant boiler, the tiny cascade of inbound water instantly boils on connection with the superheated steel shell and leads to a violent explosion that can't be managed even by security vapor valves. Draining of the boiler can also happen if a leak occurs in the steam supply lines that is larger than the make-up water supply could replace. The Hartford Loop was created in 1919 by the Hartford Steam Boiler and Insurance Company as a strategy to help prevent this condition from taking place, and therefore reduce their insurance promises.[7][8]

Superheated steam boiler

A superheated boiler on a steam locomotive.
Main article: Superheater
Most boilers produce steam to be utilized at saturation temperatures; that is, saturated steam. Superheated steam boilers vaporize the water and further heating the steam in a superheater then. This provides steam at much higher temperature, but can reduce the overall thermal efficiency of the steam generating plant because the higher vapor temperatures takes a higher flue gas exhaust temperature.[citation needed] There are many ways to circumvent this problem, by providing an economizer that heats the feed drinking water typically, a combustion air heater in the hot flue gas exhaust path, or both. You can find benefits to superheated vapor that may, and often will, increase overall efficiency of both vapor generation and its utilization: gains in input heat to a turbine should outweigh any cost in additional boiler complication and expense. There could be useful restrictions in using wet steam also, as entrained condensation droplets will harm turbine blades.

Superheated steam presents unique safety concerns because, if any system component fails and allows steam to flee, the temperature and pressure can cause serious, instantaneous harm 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 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 in this area is between 1 typically,300 and 1,600 °C (2,372 and 2,912 °F). Some superheaters are radiant type; that is, they absorb high temperature by rays. Others are convection type, absorbing heat from a liquid. Some are a mixture of the two types. Through either method, the extreme heat in the flue gas route will also temperature the superheater steam piping and the steam within. While the temperature of the vapor in the superheater goes up, the pressure of the vapor does 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 damage to the turbine blading and associated piping.

Supercritical steam generator

Boiler for a charged power plant.
Main article: Supercritical steam generator
Supercritical steam generators are frequently used for the production of energy. They operate at supercritical pressure. As opposed 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 to occur; the fluid is liquid nor gas but a super-critical fluid neither. There is absolutely no era of vapor bubbles within water, because the pressure is above the critical pressure point of which steam bubbles can form. As the liquid expands through the turbine phases, its thermodynamic state drops below the critical point as it does work turning the turbine which converts the power generator from which power is ultimately extracted. The fluid at that time may be 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 word "boiler" should not be used for a supercritical pressure vapor generator, as no "boiling" occurs in this device.
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Accessories
Boiler fittings and accessories
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 operating pressuretrol, which handles when the boiler fires to keep pressure, and for boilers outfitted with a modulating burner, a modulating pressuretrol which handles the quantity of fire.
Security valve: It can be used to relieve pressure and prevent possible explosion of the boiler.
Water level indications: They show the operator the level of fluid in the boiler, also called a sight glass, water measure or drinking water column.
Bottom blowdown valves: They offer a means for removing solid particulates that condense and rest on underneath of a boiler. As the name indicates, this valve is located directly on underneath of the boiler usually, and is sometimes opened to use the pressure in the boiler to drive these particulates out.
Continuous blowdown valve: This allows a small level of water to flee continuously. Its purpose is to prevent 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 vapor - a disorder 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. Mostly entirely on a drinking water boiler.
Flash container: High-pressure blowdown enters this vessel where the vapor can 'flash' safely and become 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 moving to the boiler, thereby transferring the maximum amount of heat possible from the blowdown to the make-up water. No flash container is generally needed as the blowdown discharged is near to the temp of the makeup water.
Hand holes: These are metal plates installed in openings in "header" to permit for inspections & installation of pipes and inspection of inner surfaces.
Vapor drum internals, some display, scrubber & cans (cyclone separators).
Low-water cutoff: It is a mechanical means (usually a float switch) that is used to turn from the burner or shut down fuel to the boiler to prevent it from jogging once the water moves below a certain point. If a boiler is "dry-fired" (burnt without water in it) it can cause rupture or catastrophic failure.
Surface blowdown series: It provides a means for removing foam or other lightweight 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 collection. This can be fitted to the side of the boiler, just below water level, or to the very best of the boiler.[10]
Top feed: In this design for feedwater injection, the water is fed to the top of the boiler. This can reduce boiler exhaustion caused by thermal stress. By spraying the feedwater over a series of trays the water is quickly warmed and this can reduce limescale.
Desuperheater tubes or bundles: Some pipes or bundles of pipes in the water drum or the steam drum designed to cool superheated vapor, in order to provide auxiliary equipment that will not need, or may be damaged by, dry out vapor.
Chemical 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 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 measure attachment:
Name dish:
Registration dish:

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