![]() Babcock and Wilcox boiler Construction: • A horizontal steam and water drum: this is the main part of the boiler. It is supported by a steel structure at a certain height and is independent of brickworks. Babcock and Wilcox Boiler. - Download as PDF File (.pdf), Text File (.txt) or read online. Babcock And Wilcox Construction CompanyThe size of the boiler drum is small as compared with the boiler drum of a fire-tube boiler of the same capacity. It has water and steam. Iso 2768 hole tolerance symbol. All safety and control devices are mounted on the boiler drum. • A bundle of steel tubes: the front end of the boiler drum is connected to the uptake header (water box) by a short tube and the rear end is connected to the down take header (water box) by a long tube. ![]() In between the headers, a number of small-diameter steel tubes are fitted at an angle of 5° to 15° with the horizontal to promote the water circulation. These steel tubes are arranged in the combustion chamber in a zigzag way so that more surface area of the tube is exposed to hot gases. • Combustion chamber: it is the space above the grate, below the front end of the drum where combustion of fuel takes place. This chamber enclosed by brickwork and is lined from inside by fire bricks. Doors are provided to give access for cleaning, inspection, and repairing. The combustion chamber is divided into the separate compartments above the furnace is the hottest and the last chamber is of lowest temperature. This makes the path of hot gases longer before leaving the boiler through the chimney.The superheater is placed between the drum and water tubes. Dampers are provided at the rear end of the chamber to regulate the fresh air supply for maintaining proper combustion of fuel. • Safety and control devices: They are called mountings, as basically these devices mount over boiler drum. These are the safety valve, pressure gauge, water-level indicator, feed check valve, steam-stop valve, blow of cock, fusible plug, and manhole. Operation: • The water in Babcock and Wilcox boilers pumped by a feed pump and it enters the drum through the feed check valve up to the prespecified level so that the headers and tubes are always flooded. When the combustion takes place above the grate, the products of hot gases come out and rush through each compartment of the combustion chamber. Hence, the rear part of the tubes has the lowest temperature and the front part of the tubes as highest temperature. When water is heated inside the tube. Due to continuous heat supply, some of the water gets vaporized into steam inside the tubes and a mixture of water and steam enters the boiler drum through the uptake header. The cold water from the boiler drum comes down through the uptake header and enters the lower end of the water tubes for getting heated further. This natural circulation is called thermosiphon system.
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