BAB 1

TOPIC 1STEAM POWER PLANT( LOJI JANAKUASA STIM )OUT COMES This topic describes the steam power plant application, main components of a steam power plant, boilers, the various connections to boiler and the types of boiler, construction, function of 13 essentials fitting, the purpose and use of heat conserving equipment / thermal insulation facility of a steam power plant also discussed.

Nesjavellir Power Plant in Iceland

A thermal power station near Sofia, BulgariaMohave Generating Station near Laughlin Nevada (1,580 MW)Pengkelasan Operasi Loji Kuasa StimLitar gas relauLitar stimLitar air penyejuk pemeluwapLitar udara penyejukSteam Power Plant

Steam Power Plant DesignDandang (boiler)Turbin stim (steam turbine)Pemeluwap (condensor)Tangki bekalan (feed tank)Pam bekal (feed pump)Menara penyejuk (cooling tower)Pemanas lampau (super heater) Komponen asas dalam Loji Kuasa Stim

Susun atur asas bagi sebuah loji kuasa stim DANDANG (BOILER) Dandang digunakan untuk menjana stim bagi menggerakkan penggerak utama (prime mover).

Dandang adalah bekas tertutup, dimana air di bawah tekanan ditukar menjadi stim akibat menerima haba hasil dari pembakaran bahan api.DANDANG (BOILER) Bentuk dandang adalah seperti sebuah silinder tertutup.Pelbagai jenis reka bentuk dandang, umumnya dandang tiub api dandang tiub air. Diperbuat daripada keluli. Dram (gelendong) dan tiub biasanya terletak di bahagian atas relau.

DANDANG (BOILER) Air yang dirawat secara kimia akan dipam ke dalam dram (gelendong). Air dipanaskan secara pembakaran bahan api di dalam relau, atau secara penyaluran gas bersuhu tinggi di dalam penukar haba.Stim yang dijana boleh mencapai tekanan maksimum 240Mpa dengan suhu maksimum 540 darjah C. Authorized Safe Working Pressure (ASWP)Means the maximum possible pressure at which a steam boiler or unfired pressure vessel may be operated as assigned by the Chief Inspector and as stated on the current certificate of fitness relating to such steam boiler or unfired pressure vessel

Chief Inspector and Inspector mean officer appointed under section 4(1) of the ActDesign Pressure ..Means the maximum pressure at which the manufacturer of the steam boiler or unfired pressure vessel or any setting or pipe work associated there with designed the same to operate. Working PressureNormal operating pressure of the boiler which is always lower than the ASWP

Basic Boiler PrincipleA boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications Basic Boiler PrincipleDirection of axis of shell @ drum vertical / horizontalThe way of erected stationary , portable, marineLocation of the furnace internally @ externally firedPosition of water & hot gases water tube @ fire tube.As special boiler natural circulation, force circulation and one through

Basic Boiler PrincipleThere are 3 range of boiler depending on usage

LOW PRESSURE STEAM BOILERraging up to 15 psi Used for space heating, cooking, and hot water distribution within buildingBasic Boiler PrincipleThere are 3 range of boiler depending on usage

MEDIUM PRESSURE STEAM BOILERraging between 25psi to 50psiUsed in industrial heating, cooking, and sterilizationBasic Boiler PrincipleThere are 3 range of boiler depending on usage

HIGH PRESSURE STEAM BOILERPressure more than 100psi

Basic Boiler PrincipleClassed by the relative arrangement of hot gas passages, for example Water tube boiler. Fire tube boiler Water tube boilerFire tube boilerBoiler Principle

Diagram of a fire-tube boiler Boiler Principle

Diagram of a water-tube boiler TUGASAN INDIVIDUApakah yang membezakan antara tiub dan paip

15 psi = ? Bar

FIRE TUBE BOILERA fire-tube boiler is a type of boiler inwhich hot gases from a fire passthrough one or more tubes runningthrough a sealed container of water.

FIRE TUBE BOILERThe heat energy from the gasespasses through the sides of the tubesby thermal conduction, heating thewater and ultimately creating steam.FIRE TUBE BOILERTypes of fire tubes boilerHorizontal Fire-Tube boilerVertical Fire-Tube boilerLancashire boilerCornish boiler Scotch marine boiler Locomotive boilerFIRE TUBE BOILERFIRE TUBE BOILERa. Horizontal ReturnTubular boiler

Horizontal Return Tubular boiler (HRT) has a horizontal cylindrical shell, containing several horizontal flue tubes, with the fire located directly below the boiler's shell, usually within a brickwork setting

Flue : serombong asap;serombongBrickwork : binaan bata

FIRE TUBE BOILER

Horizontal Return Tabular (HRT)FIRE TUBE BOILERb. Vertical boiler

Type of fire-tube boiler where the boiler barrel is oriented vertically instead of the more common horizontal orientation. Vertical boilers were used for a variety of steam-powered vehicles and other mobile machines, including early steam locomotives.

barrel : tong

Three river steamboats featuring a vertical boiler FIRE TUBE BOILER

Side-section of a Scotch marine boiler: the arrows show direction of flue gas flow; the combustion chamber is on the right, the smokebox on the left. Lancashire boiler in Germany OPERATION OF FIRE TUBE BOILERFIRE TUBE BOILEROperationIn the locomotive-type boiler, fuel is burnt in a firebox to produce hot combustion gases.

The firebox is surrounded by a cooling jacket of water connected to the long, cylindrical boiler shell.

Schematic diagram of a "locomotive" type fire-tube boiler The hot gases are directed along a series of fire tubes, or flues, that penetrate the boiler and heat the water thereby generating saturated ("wet") steam.

The steam rises to the highest point of the boiler, the steam dome, where it is collected. thereby : dengan yang demikian

Schematic diagram of a "locomotive" type fire-tube boiler FIRE TUBE BOILEROperationThe dome is the site of the regulator that controls the exit of steam from the boiler.

Schematic diagram of a "locomotive" type fire-tube boiler FIRE TUBE BOILEROperationFIRE TUBE BOILERPembinaan dan rekabentuk mudah

kos permulaan yang rendah

Padat dalam rekabentuk

Menduduki ruang lantai yang minimaKebuk dan sambungan terdedah kepada haba relau, menambahkan bahaya letupan

Isipadu adalah besar dan peredaran air kurang baik, mengakibatkan reaksi yang perlahan kepada perubahan kepada keperluan stim

Muatan, tekanan dan suhu stim adalah terhad

Masa diperlukan untuk menjalankan dandang daripada sejuk adalah lama disebabkan peredaran air kurang baik. Kelebihan dandang tiub apiKekurangan dandang tiub apiWATER TUBE BOILERWATER TUBE BOILERA water-tube boiler is a type of boiler in which water circulates in tubes heated externally by the fire.

Water-tube boilers are used for high-pressure boilers WATER TUBE BOILERStraight-tube water tube boiler

Vertical water tube boiler

Bent-tube boiler

Modern bent-tube boilersClassified into

WATER TUBE BOILER

(a) Longitudinal-drum type(b) cross-drum type.Early straight-tube water tube boiler. a. Straight-tubeWATER TUBE BOILER

b. Vertical water tube boilerWATER TUBE BOILER

c. Bent-tube boilerWATER TUBE BOILERc. Bent-tube boiler

WATER TUBE BOILER

Type A

Jenis D

Jenis O

d. Modern Bent-Tube BoilersOPERATION OF WATER TUBE BOILERWATER TUBE BOILERFuel in water-tube boiler is burned inside the furnace, creating hot gas which heats up water in the steam-generating tubes

WATER TUBE BOILERIn smaller boilers, additional generating tubes are separate in the furnace, while larger utility boilers rely on the water-filled tubes that make up the walls of the furnace to generate steam.

WATER TUBE BOILERThe heated water then rises into the steam drum. Here, saturated steam is drawn off the top of the drum. In some services, the steam will reenter the furnace in through a superheater in order to become superheated.

WATER TUBE BOILERSuperheated steam is used in driving turbines. Since water droplets can severely damage turbine blades, steam is superheated to 730F (390C) or higher in order to ensure that there is no water entrained in the steam.

WATER TUBE BOILERMenggunakan tiub bergarispusat kecil bagi membolehkan penghantaran haba berlaku dengan cepatKerosakkan pada tiub kecil tidak akan mengakibatkan letupan.Peredaran air adalah baik, oleh itu stim boleh didapati dengan cepat apabila dipanas daripada sejuk.Tekanan dan suhu tinggi disebabkan oleh saiz kebuk kecil, dan banyak stim boleh diperolehi.Semua bahagian-bahagian senang didekati untuk dibersihkan, diperiksa dan diperbaiki.Reaksi dengan cepat kepada keperluan stimKadar kecekapan yang tinggiKos pembinaan tinggi pada permulaannya.Proses pembersihan adalah sukar merujuk kepada rekabentuknya.Menggunakan tiub yang terlampau banyak.Terdapat tiub-tiub berbeza saizSaiznya yang besar merupakan satu isuKekurangan Dandang Tiub Air Kelebihan Dandang Tiub Air WATER TUBE BOILERFunction of baffles Support the tubes for structural rigidity,Prevent tube vibration and saggingDivert the flow across the bundleObtain a higher heat transfer coefficient

rigidity : ketegaran;kekakuan

WATER TUBE BOILER

Schematic flow through baffles tube bundles. Effect of bafflesLEKAPAN DANDANGLEKAPAN DANDANG Lekapan dandang bermaksud komponen asas yang terpasang pada dandang untuk membantu kecekapan dan keselamatan dandang semasa dioperasikanLEKAPAN DANDANGInjap keselamatan (safety valve)Tolok tekanan (pressure gauge)Injap tiub turun (blowdown valve)Pam suaan (feed water pump)Feed water check valvePalam boleh lebur (fusible plug)AntaranyaLEKAPAN DANDANGLow water fuel cut outMain steam stop valveTolok air (glass gauge)Tiang air (water column)Injap-injap AntaranyaLEKAPAN DANDANGInjap keselamatan (safety valve)Untuk menjamin tekanan dandang tidak melebihi tekanan selamat yang telah disetkan.

Melepaskan stim yang berlebihan ke atmosfera dan menutupkannya secara automatik apabila tekanan dandang kembali normal.

Injap ini terbahagi kepada dua iaitu jenis tetap dan boleh laras.

Dipasang pada bahagian atas dandang atau bahagian stim terkumpul.LEKAPAN DANDANG

Exterior and sectional views of spring pop safety valveLEKAPAN DANDANG

A. spring compressionB. lifting gearC. spindleD. back pressureE. blow down controlF. lift stop adjustmentG. groove disk holderH. upper adjusting ringI. thermel disk seatJ. inlet neckK. inlet connectionConsolidated maxi flow safety valve

LEKAPAN DANDANGTo release the boiler pressure in the event of high pressure exceeding the ASWP

must be able to discharge the steam & maintain pressure NOT MORE THAN 10 % ASWP

LEKAPAN DANDANGTolok tekanan (pressure gauge)Untuk mengetahui tekanan stim dalam dandang.

Tolok Bourdon adalah alatan yang sesuai

Terletak pada bahagian atas dandang atau bahagian stim terkumpul.LEKAPAN DANDANG

Steam pressure gaugesLEKAPAN DANDANG

Various forms of connection for a stem gauge LEKAPAN DANDANGBlowdown valve

to remove impurities and control water level

LEKAPAN DANDANGFeed Water Pump

to draws water from feed tank and deliver it under pressure to the boiler

LEKAPAN DANDANGFeed Water Check Valve

Feed Water Check Valve is to control amount of water to the boiler & to prevent backflow of feed water from boiler

LEKAPAN DANDANGPrevent backflow of feed water from boiler

LEKAPAN DANDANGPalam boleh lebur (fusible plug)Pada dandang tiub air, dipasang pada bahagian paling atas ruang pembakaran.

Tidak sesuai untuk dandang yang menggunakan gas sebagai bahan pemanas

Keadaan normal palam tidak akan lebur sebab disejukkan oleh air disekelilinginya

Pada dandang tiub api, dipasang pada paras air paling minima yang diperlukan oleh dandang

Tetapi sekiranya paras air berkurangan dan mendedahkan palam pada haba pemanasan, maka timah pada saluran tengah palam akan melebur dan membenarkan stim ditolak ke ruang pembakaran bagi memadamkan api pembakaran

to give early protection from direct heat in the event of loss of water boiler use in solid fuel boiler

LEKAPAN DANDANGThree fusible plug design in commonUse on steam boiler

WatersideBolt-head firesideSocket-head fireside

LEKAPAN DANDANG

Palam boleh lebur (fusible plug)LEKAPAN DANDANG to stop the boiler immediately by cut out fuel & air supply in the event of very low water level

LEKAPAN DANDANGMain Stop Valve

to put boiler into service & stop the steam supply when boiler is shut down

LEKAPAN DANDANGTolok air (glass gauge)Penunjuk paras air dalam dandang

Diperbuat daripada kaca bulat dan ditandakan dengan tiga tandaanparas air paling minimaparas air pertengahan paras air paling maksima

Dipasang pada kedudukan bawahnya terletak dua inci lebih atas dari paras air dandang yang terendah. Ini bertujuan untuk memastikan tidak ada sebarang kerosakkan sebelum paras terendah tercapaiLEKAPAN DANDANG

Tolok Air (Gauge Glass)Low-pressure gauge glassHigh-pressure gauge glassLEKAPAN DANDANGTiang air (water column)Tiang air disambung antara bahagian atas (stim) dengan bahagian bawah (air dandang)

Berfungsi sebagai penstabil dan mencegah air daripada naik dan turun dengan keterlaluan dalam tolok air

Juga bertindak sebagai perangkap kekotoran kerana ia mudah ditanggalkan dan dibersihkanLEKAPAN DANDANG

Water column on the fire tube boiler

LEKAPAN DANDANG

Water column on the water tube boilerPEMELUWAPPEMELUWAP PERMUKAAN DAN MENARA PENYEJUKPemeluwap Permukaan

Classified into two main types the coolant and condensate PEMELUWAP PERMUKAAN DAN MENARA PENYEJUKPemeluwap PermukaanCondenser is a heat exchanger which condenses a substance from its gaseous to its liquid state. In so doing, the latent heat is given up by the substance, and will transfer to the condenser coolant. Use of cooling water or surrounding air as the coolant is common in many condensers. PEMELUWAP PERMUKAAN DAN MENARA PENYEJUKPemeluwap Permukaan

Tray condenserPEMELUWAP PERMUKAAN DAN MENARA PENYEJUKPemeluwap Permukaan

Spray condenser Forced draft, air cooled exchanger used as a condensor

PEMELUWAP PERMUKAAN DAN MENARA PENYEJUKPemeluwap Permukaan

Example of shell-side condenser with a single tube-side passPEMELUWAP PERMUKAAN DAN MENARA PENYEJUKPemeluwap Permukaan

Tubular Exchanger Manufacturers Association (TEMA) shell-type condenserPEMELUWAP PERMUKAAN DAN MENARA PENYEJUKPemeluwap Permukaan

Basic construction of a plate-fin exchangerPEMELUWAP PERMUKAAN DAN MENARA PENYEJUKPemeluwap Permukaan

Spiral exchanger for condenser applicationPEMELUWAP PERMUKAAN DAN MENARA PENYEJUK

Cooling Tower (Menara Penyejuk)PEMELUWAP PERMUKAAN DAN MENARA PENYEJUKCooling Tower (Menara Penyejuk)

PEMELUWAP PERMUKAAN DAN MENARA PENYEJUKCooling Tower (Menara Penyejuk)Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere.PEMELUWAP PERMUKAAN DAN MENARA PENYEJUKCooling Tower (Menara Penyejuk) Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or rely solely on air to cool the working fluid to near the dry-bulb air temperature. PEMELUWAP PERMUKAAN DAN MENARA PENYEJUKCooling Tower (Menara Penyejuk)Common applications include cooling the circulating water used in oil refineries, chemical plants, power plants and building cooling. PEMELUWAP PERMUKAAN DAN MENARA PENYEJUKCooling Tower (Menara Penyejuk)The towers vary in size from small roof-top units to very large hyperboloid structures (as in Image 1) that can be up to 200 meter tall and 100 meter in diameter, or rectangular structures (as in Image 2) that can be over 40 meter tall and 80 meter long. PEMELUWAP PERMUKAAN DAN MENARA PENYEJUKCooling Tower (Menara Penyejuk)Smaller towers are normally factory-built, while larger ones are constructed on site PEMELUWAP PERMUKAAN DAN MENARA PENYEJUKCooling Tower (Menara Penyejuk)

Image 1Natural draft wet cooling hyperbolic towers at Didcot Power Station, UK PEMELUWAP PERMUKAAN DAN MENARA PENYEJUK

Image 2A mechanical induced draft cooling tower PERALATAN PENJIMATFungsi peralatan penjimatMeningkatkan kecekapan, menjimatkan kos kendalian dan memastikan kadar kehilangan haba paling minimastim yang telah diekzoskan (primary feed water heater), atau

gas panas hasil pembakaran (secondary feed water heater) Berfungsi dengan bantuan PERALATAN PENJIMATPERALATAN PENJIMATPemanas lampau (superheater)Pemanas air suaan (feed water heater) sistem terbukasistem tertutupPenjimat (economizer)Pra pemanas udara (pre-air heater)Pembersih stim (stim purifier)Peralatan Penjimat habaPERALATAN PENJIMATa. Pemanas Lampau (Superheater)A superheater is a device in a steam engine that heats the steam generated by the boiler again, increasing its thermal energy and decreasing the likelihood (kemungkinan) that it will condense (memeluwap) inside the engine.PERALATAN PENJIMATa. Pemanas Lampau (Superheater)Superheaters increase the efficiency of the steam engine. Steam which has been superheated is logically known as superheated steam.PERALATAN PENJIMATa. Pemanas Lampau (Superheater)

General arrangement of a superheater installation in a steam locomotive PERALATAN PENJIMATa. Pemanas Lampau (Superheater)

Superheater viewed from the smokebox.

Top center is the superheater header, with pipes leading to cylinders.

Tubes below feed steam into and out of the superheater elements within the flues (serombong).

The stack and the damper have been removed for clarity (kejelasan). PERALATAN PENJIMATb. Pemanas air suaan (feed water heater) Boiler feed water is water used to supply ("feed") a boiler to generate steam or hot water.

At thermal power stations, the feed water is usually stored, pre-heated and conditioned in a condensor, and forwarded into the boiler by a boiler feed water pump.PERALATAN PENJIMATb. Pemanas air suaan (feed water heater)

Sistem pemanas air suapan terbukaPERALATAN PENJIMATb. Pemanas air suaan (feed water heater)

Sistem pemanas air suapan tertutupPERALATAN PENJIMATc. PenjimatEconomizers are heat exchange devices that heat fluids, usually water, up to but not normally beyond the boiling point of that fluid.

Economizers are so named because they can make use of the enthalpy in fluid streams that are hot, but not hot enough to be used in a boiler, thereby recovering more useful enthalpy and improving the boiler's efficiency.

They are a device fitted to a boiler which saves energy by using the exhaust gases from the boiler to preheat the cold water used to fill it (the feed water). Enthalpy ?In thermodynamics and molecular chemistry, the enthalpy (denoted as H, h, or rarely as ), which can be used to calculate the heat transfer during a quasi-static process (kelihatan seperti proses tetap) taking place in a closed thermodynamic system under constant pressure.The term enthalpy was composed of the prefix en-, meaning "to put into" and the Greek word -thalpein, meaning "to heat", although the original definition is thought to have stemmed (kata dasar) from the word "enthalpos" PERALATAN PENJIMATd. Pra-Pemanas UdaraAn air preheater or air heater is a general term to describe any device designed to heat air before another process (for example, combustion in a boiler) with the primary objective of increasing the thermal efficiency of the process.

They may be used alone or to replace a recuperative heat system or to replace a steam coil.PERALATAN PENJIMATd. Pra-Pemanas Udara

Schematic diagram of typical coal-fired power plant steam generator highlighting the air preheater (APH) location. (For simplicity (kemudahan), any radiant section tubing is not shown.) PERALATAN PENJIMATd. Pra-Pemanas Udara

The tubular air heater is basically a nest of tubes enclosed in a steel casingPERALATAN PENJIMATd. Pra-Pemanas Udara

Air passes inside tube while the hot gas crosses at the righ angles

Gases flow through here, while the air is directed across tubes by bafflesRAWATAN AIRRAWATAN AIRMemanjangkan hayat dandangMencegah pembentukan sisik pada permukaan panas Mengawal jumlah enap cemar dalam air dandang Mengurangkan berlakunya kakisanMengurangkan berlakunya bawa sebelah.Mencegah berlakunya rapuh kostik pada plat sambungan bagi dandang Menghapuskan oksigen terlarut kerana mengakibatkan kakisan berulang.Mengeluarkan kotoran umum dalam bekalan air semulajadi seperti gas-gas larut, kekerasan, dan bendasing. Tujuan utama rawatan air adalah untuk RAWATAN AIRPencegahan kotoran dalam dandang.Pencegahan kakisan dalam dandang.Pencegahan keretakan pada sambungan paip.Pencegahan pencemaran stim.Objektif utama dalam merawat air dandangRAWATAN AIRi.Menggunakan penyejat (evaporator) ii.Rawatan Lime Sodaiii.Rawatan lime soda sejuk iv.Rawatan ZeolitCara umum merawat airRAWATAN AIRMelibatkan rawatan air dalaman luaran.

Penambahan pelembut lime soda digunakan untuk bertindak balas dengan mineral larut serta bahan asing.

Penapisan bertujuan mengeluarkan bahan asing dan bahan bahan organik yang tak larut

Penukaran ion adalah dengan mengeluarkan bahanbahan larut ketika air melalui kawasan neutral.Kaedah Rawatan Air DandangRAWATAN AIRTindakan melembutkan air berlaku dalam dandang. Sesuai untuk loji kecil dan sederhana dimana syarat kendalian tidak ketat. Memasukkan bahan kimia terus ke dalam air bekalan dandang.a. Rawatan air dalamanRAWATAN AIRRawatan air dilakukan di tempat lain sebelum air suaan dipam masuk ke dalam dandangTerdapat loji rawatan air khas yang akan merawat air.b. Rawatan air luaranRAWATAN AIRWujud kerak Wujud enap cemarii.Terbentuk pembuasaan (foaming)Terbentuk penyebuan (priming)Bawa sebelahRapuh kostikKesan Penggunaan Air Tidak Dirawat RAWATAN AIR

PrimingA violent, spasmodic, action which result in the throwing of slugs of water with steam. It is caused by too high water level, uneven water circulation and rapid changes in a steaming rate.

FoamingCondition that results from the formation of bubbles on the drum water surface by the saponification agents like oil, high alkalinity and so onRAWATAN AIRBiologigal Oxygen Demand (BOD)BOD (permintaan oksigen biokimia) bermaksud menilai atau mengira keterlarutan oksigen yang terkandung dalam air setelah proses pereputan oleh mikroorganisma.

Chemical Oxygen Demand (COD)Bermaksud ujian kimia yang mengukur jumlah oksigen yang boleh bergabung dengan sebatian organik dalam sampel air. PEMERIKSAAN DANDANGPEMERIKSAAN DANDANGDandang lama digunakan dan tidak diselenggarakan akan mengalamiKehausanKakisanKerakMinyakKeretakan Bertujuan mengelakkan berlaku letupan dandang. Pemeriksa dandang dikawal oleh DOSH. Lesen pengendalian dandang hanya boleh diperbaharui selepas pemeriksaan. Sebab kepada keperluan pemeriksaan dandangPEMERIKSAAN DANDANGMenanggalkan jelagaMeniupkan udara atau stim panas lampau pada dinding rongga pembakaran.Menyalirkan dandangMembiarkan tekanan dandang jatuh sehingga sifar seterusnya buka injap cuci supaya air keluar.Membersihkan dandangSelepas menanggalkan plat lorong (mainhole) dan lubang tangan pada bahagian air, cuci kelompang menggunakan air bertekanan tinggi.Langkah-langkah Penyediaan Dandang Untuk PemeriksaanPEMERIKSAAN DANDANGiv.Mencari kesan minyakPeriksa kebuk di sepanjang paras air untuk mengesan minyak dengan menyentuh sepanjang garisan permukaan air. Caranya..v.Menanggalkan kerakPeriksa kelompang dan tiub dalam untuk mencari sisik. Tanggalkan enapan lembut menggunakan pengikis dan sisik keras dengan menggunakan tukul serpih.vi.Jika palam boleh lebur pada drum(gelendung) stim berada di dalam keadaan boleh lebur, maka ianya perlu diganti.vii.Dandang sekarang adalah sedia untuk di periksa oleh pihak yang berkuasa.Langkah-langkah Penyediaan Dandang Untuk PemeriksaanUJIAN DANDANGUJIAN DANDANGBertujuan memeriksa kebocoran pada sambungan tiub, injap dan peralatan dalam gelendong (drum).sebelum ia digunkan pada kali pertama.selepas sebarang pembaikan yang boleh mempengaruhi atau menjejaskan kekuatan dandangpada jangka masa tidak lebih dari 7 tahun ianya digunakanUjian DandangSetiap dandang mesti menjalani ujian hidrostatikUJIAN DANDANGbertujuan mengesan kebocoran tekanan dandangbertujuan mengesan pesongan pada bahagian-bahagian dandang.bertujuan mengesan erotan pada bahagian-bahagian dandangAntara lain tujuan menjalani ujian hidrostatik keatas dandang.UJIAN DANDANGDandang dibawah 100 psi diuji pada dua kali ganda tekanan kerja maksima.

Dandang yang lebih dari 100 psi, tekanan ujian ialah tekanan kerja x 1.5 + 50 psi.UJIAN DANDANGLangkah-langkah ujian hidrostik dandang

injap keselamatan pada gelendong ditanggalkan dan ditutuptolok tekanan dandang digantikan dengan tolok tekanan pemeriksaan.gelendong diisi air hingga penuh.tekanan dinaikkan dengan mengisi kedalam dandang melalui pam suaan mengikut tempoh masa tertentubila tekan ujian telah dicapai, injap cegah balik ditutup dan pam suaan diberhentikan. tekanan mestilah dibiarkan dalam dandang sekurang-surangnya selama 20 minitjika terdapat kebocoran atau bahagian tekanan gagal, tekanan akan diturunkan.jika tekanan dipertahankan pada jeda ujian tanpa kebocoran, pesongan atau erotan , maka dandang itu diluluskan oleh pemeriksa.Faktor Pemilihan Dandang?Faktor Mengurangkan Kecekapan Dandang?end..