Technical requirements for the procurement of wear-resistant elbows and straight pipes
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1174 Pneumatic conveying is a method of transporting granular materials by fluidizing them with air (or gas) flowing in pipes; it is widely used in industries such as construction materials, chemicals, food processing, metallurgy, mining, environmental protection, light industry, and energy. There are many types of pneumatic conveying systems, which generally consist of five components: a feeding device, conveying pipes, a gas-solid separator, air supply machinery, and control elements. Compared with mechanical continuous conveying devices, it features complete sealing of the material during transportation, minimal impact from climate and environment conditions, better working conditions for workers, protection of the material from moisture, contamination, or inclusion of impurities. It also has a simple design, a compact structure, flexible layout, occupies less space, has low equipment costs, is easy to control centrally, enables automation, and improves conveying capacity. With the exception of materials that are fragile, highly adhesive, abrasive, corrosive, or prone to chemical reactions and thus require special treatment, most loose materials can be transported. This method is very convenient and environmentally friendly, as it does not cause any harm to the environment. Pneumatic conveying is developing rapidly at present; it is a widely used method of transportation and is also a common approach for transporting dust in dust removal projects. https://pic.rmb.bdstatic.com/bjh/down/d16e3218a40634ce7133a95d5f9510db.jpeg@wm_2,t_55m+5a625Y+3L+azsOaLk+mZtueTt+iAkOejqOW8r+WktA==,fc_ffffff,ff_U2ltSGVp,sz_36,x_23,y_23 https://pic.rmb.bdstatic.com/bjh/down/e67e44239d900838c3abebc8eedccac9.jpeg@wm_2,t_55m+5a625Y+3L+azsOaLk+mZtueTt+iAkOejqOW8r+WktA==,fc_ffffff,ff_U2ltSGVp,sz_36,x_23,y_23 https://pic.rmb.bdstatic.com/bjh/down/8655218bc32b069a5990a78c6efdec6a.jpeg@wm_2,t_55m+5a625Y+3L+azsOaLk+mZtueTt+iAkOejqOW8r+WktA==,fc_ffffff,ff_U2ltSGVp,sz_27,x_17,y_17 Environmental conditions: The medium transported inside the wear-resistant fittings is coal powder ； Normal operating temperature: 120°C to 160°C. Technical requirements: 1. Basic dimensions of the wear-resistant elbow: 670*10*5*90, where the outer diameter is 670 mm and the bending radius is 990 mm. 2. Basic dimensions of the wear-resistant straight pipe: 670*10*5*700, with an outer diameter of 670 mm and a length of 700 mm. 3. The inner surfaces of both the wear-resistant elbows and straight pipes are equipped with a composite ceramic wear-resistant layer formed through centrifugal casting; this layer ensures a smooth surface finish, with a surface hardness of over HRC80. 4. Add 300 meters of straight pipe sections on the inlet and outlet sides of the wear-resistant elbow; a ceramic wear-resistant coating should be applied, and proper bevels should be created at both ends to facilitate welding. 5 Provide the product’s certificate of conformity along with a quality inspection report detailing the product’s material and hardness, etc., at the time of delivery ； It also provides instructions on topics such as product cutting, welding processes, and precautions.
1. The bending radius of the gray pipe elbow should be ≮5 times the inner diameter of the pipe; the thickness of the pipe shell should be ≮10 mm. A energy-storing welding process is used to weld ceramic sheets with conical holes (δ=8 mm) to the steel body using special wear-resistant bolts. The nuts are made of high-alumina material (95% or more), while the studs are made of ordinary carbon steel. Flange connection. 2. Ceramic tiles are formed through a sintering process at high temperatures of 2000°C; direct dry pressing cannot be used for their formation. 3. Material for the ceramic lining of wear-resistant elbows and tees: Wear-resistant alumina ceramics are used, with an Al2O3 content of ≥95%. 4. Connection method between the ceramic lining and the steel pipe, as well as the structural design of the ceramics: The structure of the wear-resistant ceramic tiles features pressure on three sides, reverse pressure on three other sides, and curved surfaces on both the front and back; the tiles are fitted together to ensure overall and local resistance to detachment. 5. The specific structural configuration is: (carbon steel) + inorganic adhesive + ceramic tiles with \"pressure on three sides, reverse pressure on three sides, and curved surfaces on both sides\" + welding bolts + tapered nuts + wear-resistant sealant for sealing the holes. 6. The inner and outer surfaces of wear-resistant elbows and tees should be smooth and clean, free of burrs, rough edges, unevenities, cracks, porosity, or residues ； The painting should be even and uniform, with no powder accumulation.
There are a variety of types of wear-resistant elbows, and the following provides a detailed introduction to these different types. I. Self-propagating ceramic composite elbow: The self-propagating ceramic composite elbow is a type of composite pipe manufactured using the \"self-propagating high-temperature synthesis high-speed centrifugation technique,\" which results in the formation of a uniform, dense, and smooth ceramic layer as well as a transition layer at high temperatures and high speeds. Ceramics do not fall off at high temperatures, and they are relatively light in weight; composite ceramics possess high hardness and good wear resistance. Self-igniting ceramic straight pipes, wear-resistant elbows, ceramic tees, etc. have found extensive use in industries subject to severe wear, especially in dust removal and ash conveying pipelines, where they yield significant results. Ceramic wear-resistant elbows. II. Ceramic-lined composite steel pipes. Ceramic-lined composite pipes possess advantages such as high strength, good toughness, impact resistance, excellent weldability, high hardness, good wear resistance, corrosion resistance, and heat resistance; they overcome the shortcomings of corundum ceramics, namely low hardness, poor wear resistance, and weak toughness. Therefore, composite pipes possess good wear resistance, heat resistance, corrosion resistance, mechanical impact resistance, and thermal shock resistance, as well as excellent weldability. It is often used in wear-resistant and corrosion-resistant pipes for transporting granular materials, as well as in applications involving grinding and corrosive media. The advantages include the ability to weld directly, relatively low costs, and improved overall wear resistance of the pipes. Ceramic-lined composite steel pipe. III. Ceramic sheet wear-resistant pipe: A ceramic sheet wear-resistant pipe is one in which aluminum oxide ceramic sheets are bonded to the inner wall of the pipe using special ceramic adhesives. The organic adhesive used for bonding ceramic tiles has high strength and does not flow, allowing the ceramics and steel pipes to be bonded together seamlessly. This ceramic tile is made of alumina with a purity of 95%, offering excellent wear resistance. Its thickness can be designed according to the requirements of specific operating conditions; it is frequently used in powder delivery pipelines in power plants and large-diameter wear-resistant pipelines in coal washing plants. Ceramic sheet wear-resistant pipes. IV. Welded ceramic wear-resistant elbows – These pipes are made by using high-temperature adhesives to attach alumina ceramic sheets with holes in them to the inner wall of the pipe; simultaneously, a spot-welding process is used to firmly weld the ceramic to the inner wall of the steel pipe through those holes. To protect the solder joint, screw on the ceramic cap. The production process for welding ceramic wear-resistant elbows is relatively complex; welding combined with bonding provides dual-layer reinforcement, preventing the ceramic tiles from falling off. Such elbows are often used in pipelines that are subject to high impact forces and require high wear resistance. Welded ceramic wear-resistant elbow