The first type is the bare pipe water wall. This is the simplest structure of the water wall. The advantage is that ordinary seamless steel pipes can be used, and it is more convenient to replace the water wall pipe. The disadvantage is that the temperature of the furnace wall is still high, and heavy refractory bricks are required. The steel frame of the corresponding boiler should be strengthened. , The air leakage of the furnace wall is relatively large. Old-fashioned high-pressure boilers and medium and small boilers are used more frequently.
The second tupe is the membrane water wall. The membrane water wall is welded by seamless steel tubes with fins. The Water Wall Tubes are connected by fins to make the water wall into a whole. This kind of water wall is called a membrane water wall. Its function is to strengthen the heat transfer of the water wall and greatly reduce the temperature of the furnace wall. The furnace wall does not need refractory bricks, but only requires thermal insulation materials. Compared with the conventional heavy furnace wall, the weight can be reduced by 60% ~ 70%, the furnace wall heat storage is reduced by 80%, the start and stop time is shortened, and the fuel consumption is reduced. The load of the furnace steel frame is greatly reduced, saving refractory materials and steel.
The third type is the pierced pipe water wall. The barbed pipe water wall pipe is made by welding many grab nails with a length of 20 to 26 mm and a diameter of 6 to 12 mm on the water wall pipe. It is mainly used to lay the gas belt. Generally, for boilers that burn fuel with low calorific value and low volatile content, in order to stabilize the fire, pierced pipe water walls are often used for laying the fire protection belt.
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According to China Shipbuilding Heavy Industry News: Recently, the first 9L21/31 crankshaft of Henan Diesel Heavy Industry Co., Ltd. was successfully launched. The crankshaft is 3890mm long and has a net weight of 1,402 kilograms. It is unprecedented in the history of processing the river Chai crankshaft regardless of length or weight. Its successful trial production not only fully proves the leading technology level and manufacturing capacity of Hechai, but also lays a foundation for mass production and sales expansion.
In the trial process of the 9L21/31 crankshaft, the river Chai people carried forward the style of hard-working and hard-boiled bones, and it was difficult to attack and ensure a success. At present, the equipment for producing large-scale crankshafts in China is imported rotary grinders with a value of more than 40 million yuan, and Hechai has to process super-long crankshafts on a 5-meter ordinary grinding machine worth 6 million yuan. The difficulty is conceivable.
Since the crankshaft is the first machining, the precision and performance requirements are strict, the manufacturing process is complicated, and it is difficult to complete the machining task within two months due to the length and weight of the crankshaft and the limitations of the existing processing equipment. Hechai Heavy Industry established the 9L21/31 crankshaft trial production team, drawing on the experience of 8L21/31 crankshaft machining, fully analyzing the problems that may be foreseen in production, and formulating solutions.
Because it is processed on the ordinary grinding machine, when the connecting rod neck is refined, the machining size is caused by the self-weight of the crankshaft, and the processing size is out of tolerance. Hechai Heavy Industry exerts its advantages in the process, carries out technical research, and designs a set of eccentric roller center of the grinding machine. The frame has an ovality of 0.015 mm after machining, which ensures the machining accuracy and solves the problem of crankshaft machining. The process of the road was in full swing, and the technical problems were organized again and again. One problem was solved. The 9L21/31 crankshaft was completed in more than 40 processes, and it was successfully put into storage after passing the inspection.
The 21/31 and 16/24 series medium speed machines are the international leading products introduced by Hechai Heavy Industry in 2007 from German MAN. The mass production of two series of six models has been realized, which has greatly adjusted the structure of the products of Hechai and strengthened its position in the ship market. Especially in dealing with the financial crisis, the role of medium-speed machines in resisting market risks and supporting the development of enterprises has become more apparent. The successful development of the 9L21/31 crankshaft will accelerate the pace of serialization of the products of the river diesel engine, lengthen the product chain and broaden the market.
The boiler water wall is the main radiation heat surface, arranged inside the boiler chamber and proceeds the heat exchange directly with the high temperature flame. The convection tubes are the convection heat surface of the boiler, arranged between the boiler chamber outlet and the end heat surface and proceed the heat exchange directly with the high temperature fume. The water wall and convection tubes are the main heat surface of the boiler, the tubes diameter for both generally usedΦ 51-60mm boiler steel tubes, also as the request.