Boiler Repairs Penge, Anerley, SE20, Boiler Breakdown Emergency Service

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# 28/11/2017 à 03:14 JamesZep (site web)
A boiler is a closed vessel in which drinking water or other fluid is heated. The liquid does not necessarily boil. (In THE UNITED STATES, the word "furnace" is normally used if the reason is never to boil the fluid.) The heated or vaporized fluid exits the boiler for use in a variety of processes or heating applications,[1][2] including drinking water heating, central heating, boiler-based power era, food preparation, 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 found in wetted parts of boilers credited to corrosion and stress corrosion cracking.[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
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), because of 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 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 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 instead shifted towards the utilization of metal, which is stronger and cheaper, with welded building, which is quicker and requires less labour. It ought to be noted, however, that wrought iron boilers corrode considerably slower than their modern-day metal counterparts, and are less vunerable to localized stress-corrosion and pitting. This makes the durability of old wrought-iron boilers significantly superior to those of welded steel boilers.

Cast iron might be used for the heating vessel of local water heaters. Although such heaters are usually termed "boilers" in some countries, their purpose is to produce hot water usually, not steam, and so they run at low pressure and stay away from boiling. The brittleness of cast iron helps it be impractical for high-pressure steam boilers.
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Energy
The foundation of heating for a boiler is combustion of any of several fuels, such as wood, coal, oil, or gas. Electric vapor boilers use level of resistance- or immersion-type heating system elements. Nuclear fission is also used as a heat source for producing steam, either directly (BWR) or, generally, in specialised heat exchangers called "steam generators" (PWR). Warmth recovery steam generators (HRSGs) use heat rejected from other processes such as gas turbine.

Boiler efficiency
there are two methods to gauge 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 steam circulation Hg= Enthalpy of saturated vapor in k cal/kg Hf =Enthalpy of give food to drinking water in kcal/kg q= level of energy 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 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:

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 vapor generally, often barely above that of the atmosphere. These could burn off wood or most often, coal. Efficiency was suprisingly low.
Flued boiler with a couple of 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 small volume still left above to support the steam (steam space). This is the type of boiler used in nearly all steam locomotives. Heat source is inside a furnace or firebox that has to be kept permanently 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 can be further increased by causing the gases reverse direction through another parallel tube or a bundle of multiple pipes (two-pass or come back flue boiler); additionally the gases may be studied along the edges and then under the boiler through flues (3-move boiler). In case there is a locomotive-type boiler, a boiler barrel expands from the firebox and the hot gases go through a bundle of fire pipes inside the barrel which greatly increases the heating system surface compared to a single tube and further enhances heat transfer. Fire-tube boilers have a comparatively low rate of vapor creation usually, but high vapor storage capacity. Fire-tube boilers mainly burn off solid fuels, but are readily adaptable to those of the gas or water variety.

Diagram of the water-tube boiler.
Water-tube boiler: In this type, tubes filled with water are arranged in the furnace in several possible configurations. Usually the water tubes connect large drums, the lower ones filled with water and top of the ones steam and drinking water; in other cases, like a mono-tube boiler, water is circulated with a pump through a succession of coils. This kind generally provides high steam production rates, but less storage capacity than the above. Water tube boilers can be designed to exploit any temperature source and are generally preferred in high-pressure applications since the high-pressure water/vapor is contained 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 jointly and drinking water is pumped through them. A flash boiler differs from the type 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 vapor and superheated. Flash boilers experienced some use in cars in the 19th century and this use continued in to 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 mixed in the next manner: the firebox consists of an assembly of water tubes, called thermic siphons. The gases then pass through a typical 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 ensemble iron sectional boiler, sometimes called a "pork chop boiler" the water is contained inside solid 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 such as the American Society of Mechanical Technical engineers (ASME) develop requirements and regulation rules. For instance, the ASME Boiler and Pressure Vessel Code is a typical providing a wide range of guidelines 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 due to badly understood engineering principles. Thin and brittle steel shells can rupture, while badly welded or riveted seams could open up, resulting in a violent eruption of the pressurized steam. When drinking water is changed into steam it expands to over 1,000 times its original quantity and moves down vapor pipes at over 100 kilometres per hour. Because of this, steam is a great way of moving energy and heat around a niche site from a central boiler house to where it is necessary, but with no right boiler give food to water treatment, a steam-raising herb will suffer from scale corrosion and formation. At best, this raises energy costs and can result in 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 spray scalding-hot vapor and smoke from the air intake and firing chute, injuring the firemen who load the coal into the fireplace chamber. Extremely large boilers providing a huge selection of horsepower to use factories could demolish entire buildings.[6]

A boiler that has a loss of feed water and it is permitted to boil dry out can be hugely dangerous. If give food to drinking water is sent in to the clear boiler then, the small cascade of inbound water instantly boils on contact with the superheated metal shell and leads to a violent explosion that can't be managed even by protection steam 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 invented in 1919 by the Hartford Steam Boiler and Insurance Company as a method to assist in preventing this problem from happening, and thereby reduce their insurance claims.[7][8]

Superheated steam boiler

A superheated boiler on a steam locomotive.
Main article: Superheater
Most boilers produce vapor to be used at saturation heat range; that is, saturated steam. Superheated steam boilers vaporize the water and then further high temperature the vapor in a superheater. This provides steam at much higher heat range, but can decrease the overall thermal efficiency of the steam generating place because the higher steam heat range takes a higher flue gas exhaust temp.[citation needed] There are several ways to circumvent this problem, typically by providing an economizer that heats the give food to water, a combustion air heating unit in the hot flue gas exhaust route, or both. A couple of benefits to superheated vapor that may, and often will, increase overall efficiency of both steam generation and its utilization: benefits in input temp to a turbine should outweigh any cost in additional boiler problem and expense. There could be practical restrictions in using moist vapor also, 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 extreme heat and sound from such a leak obviously indicates its presence.

Superheater procedure 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 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 glowing type; that is, they absorb heat by rays. Others are convection type, absorbing high temperature from a liquid. 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 temperatures 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 avoid harm 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 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 steam bubbles within the water, because the pressure is above the critical pressure point of which steam bubbles can develop. As the fluid expands through the turbine stages, its thermodynamic state drops below the critical point as it does work turning the turbine which changes the power generator that power is ultimately extracted. The fluid at that point 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 steam generator, as no "boiling" occurs in this device.
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Accessories
Boiler accessories and fittings
Pressuretrols to control 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 the top limit of vapor pressure, the operating pressuretrol, which controls when the boiler fires to keep pressure, as well as for boilers outfitted with a modulating burner, a modulating pressuretrol which handles the amount of fire.
Security valve: It is used 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 glass also, water measure or water column.
Bottom level blowdown valves: They provide a means for removing solid particulates that condense and lie on the bottom of the boiler. As the name indicates, this valve is located directly on the bottom of the boiler usually, and is sometimes opened to use the pressure in the boiler to press these particulates out.
Continuous blowdown valve: This enables a small level of water to flee 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 - a condition 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 found on a drinking water boiler commonly.
Flash container: High-pressure blowdown enters this vessel where in fact the vapor can 'flash' safely and be found in a low-pressure system or be vented to atmosphere while the ambient pressure blowdown moves to drain.
Automatic blowdown/continuous heat recovery system: This system allows the boiler to blowdown only when make-up water is moving 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 near to the temp of the make-up water.
Hand holes: They may be metal plates installed in openings in "header" to permit for inspections & installing pipes and inspection of internal surfaces.
Steam drum internals, some display, scrubber & cans (cyclone separators).
Low-water cutoff: It really is a mechanical means (usually a float switch) that is used to turn off the burner or shut off fuel to the boiler to avoid it from running once the water moves below a certain point. If a boiler is "dry-fired" (burned without drinking water in it) it can cause rupture or catastrophic failure.
Surface blowdown line: It offers a way for removing foam or other light-weight non-condensible chemicals that have a tendency to float together with water inside the boiler.
Circulating pump: It is designed to circulate water back again 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 line. This may be installed to the medial side of the boiler, below the water level just, or to the very best of the boiler.[10]
Top give food to: Within 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 a series of trays water is quickly warmed which can reduce limescale.
Desuperheater tubes or bundles: A series of tubes or bundles of pipes in the water drum or the steam drum designed to cool superheated vapor, in order to provide auxiliary equipment that does 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:energy oil heaters
Gas system:
Coal system:
Soot blower
Other essential items
Pressure gauges:
Feed pumps:
Fusible plug:
Inspectors test pressure gauge attachment:
Name plate:
Registration plate:
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