Shot Blasting Derusting Machine for Steel Pipe Outer Walls
The outer wall of steel pipes is often exposed to the external environment during storage, transportation, and use, making it susceptible to rust, oxide scale formation, and contamination by dust and oil stains. These contaminants not only affect the appearance of steel pipes but also reduce their corrosion resistance and service life. Shot blasting derusting machines for steel pipe outer walls are specially designed to solve this problem, providing an efficient, reliable, and environmentally friendly solution for derusting and surface treatment of steel pipe outer walls. This article comprehensively discusses shot blasting derusting machines for steel pipe outer walls, including their working principle, structural composition, technical features, application scenarios, advantages, operation process, and maintenance and repair methods.
The working principle of a shot blasting derusting machine for steel pipe outer walls is based on the physical impact of high-speed projectiles. The machine uses blast wheels to accelerate abrasives (such as steel shots, steel grit, and aluminum oxide) to a high speed (usually 60-100 m/s) and then sprays them onto the outer wall of the steel pipe. The kinetic energy of the high-speed projectiles is converted into impact energy when they collide with the outer wall of the steel pipe, effectively removing rust, oxide scales, dust, oil stains, and other contaminants. At the same time, the impact of the projectiles causes work hardening on the surface of the steel pipe, increasing the surface hardness and fatigue strength. In addition, the impact also forms a uniform rough surface on the outer wall, which is conducive to the adhesion of anti-corrosion coatings, further improving the corrosion resistance of the steel pipe. Compared with traditional derusting methods such as manual grinding and chemical pickling, shot blasting derusting has the advantages of high efficiency, uniform treatment, and no environmental pollution.
The structural composition of a shot blasting derusting machine for steel pipe outer walls is complex, consisting of several key components that work together to achieve the derusting effect. The main components include the blast chamber, blast wheel system, steel pipe conveying and rotating system, abrasive recycling system, dust removal system, and electrical control system. The blast chamber is the main working area where the steel pipe outer wall derusting is carried out. It is usually made of high-wear-resistant materials (such as manganese steel plates) to withstand the continuous impact of projectiles. The inner wall of the blast chamber is often lined with wear-resistant liners, which can be replaced when worn to extend the service life of the blast chamber.
The blast wheel system is the core power component of the machine, responsible for accelerating the abrasives. A shot blasting derusting machine for steel pipe outer walls is usually equipped with multiple blast wheels, which are arranged around the steel pipe to ensure that the projectile stream can cover the entire circumference of the steel pipe's outer wall. The number and arrangement of blast wheels depend on the diameter of the steel pipe and the required derusting efficiency. For example, for large-diameter steel pipes, more blast wheels are needed to ensure uniform derusting. The blast wheels are composed of impellers, blades, and rotating shafts. The blades are easily worn parts and need to be made of high-wear-resistant materials (such as high-chromium cast iron).
The steel pipe conveying and rotating system is used to transport the steel pipe through the blast chamber and drive it to rotate during the derusting process. This system ensures that every part of the steel pipe's outer wall is uniformly subjected to the impact of projectiles. Common conveying methods include roller conveying, chain conveying, and belt conveying. Roller conveying is the most widely used method because it can adapt to steel pipes of different diameters and lengths and has stable conveying performance. The rotating mechanism is usually driven by a motor and a reducer, which drives the rollers to rotate, thereby driving the steel pipe to rotate. The rotation speed of the steel pipe is adjustable, and operators can set the appropriate speed according to the derusting requirements.
The abrasive recycling system is designed to collect, clean, and reuse the abrasives, reducing production costs and environmental pollution. This system mainly includes a hopper, screw conveyor, bucket elevator, separator, and storage silo. After the projectiles collide with the steel pipe's outer wall, they fall into the hopper at the bottom of the blast chamber. The screw conveyor transports the projectiles and debris to the bucket elevator, which lifts them to the separator. The separator uses the principle of gravity and wind force to separate usable abrasives from debris and dust. The usable abrasives are stored in the silo and reused in the shot blasting process, while the debris and dust are discharged to the dust removal system.
The dust removal system is an essential part of the machine, as shot blasting derusting generates a large amount of dust and debris that are harmful to the environment and human health. The dust removal system usually consists of a dust collector, dust collection pipeline, and fan. Common dust collectors include bag-type dust collectors, cyclone dust collectors, and electrostatic precipitators. Bag-type dust collectors are widely used due to their high dust collection efficiency (up to 99% or more) and ability to capture fine dust particles. The dust collection pipeline connects the blast chamber and the dust collector, and the fan provides the suction force to transport the dust to the dust collector for filtration and purification. The purified air is discharged into the atmosphere, and the collected dust is disposed of centrally.
The electrical control system is responsible for controlling the operation of the entire machine, integrating the control of the blast wheel system, conveying and rotating system, abrasive recycling system, and dust removal system. Modern shot blasting derusting machines are often equipped with PLC (Programmable Logic Controller) control systems, which enable automatic operation, parameter setting, and fault alarm. Operators can monitor the machine's operation status through the touch-screen interface and adjust parameters such as the rotating speed of the blast wheels, the conveying speed of the steel pipes, and the supply amount of abrasives according to the derusting requirements.
Key technical features of shot blasting derusting machines for steel pipe outer walls include the processing range, derusting efficiency, surface roughness, and abrasive consumption. The processing range refers to the diameter and length of the steel pipes that the machine can handle. Different models of machines have different processing ranges, which can usually handle steel pipes with diameters ranging from 50mm to 2000mm and lengths ranging from 3m to 18m. The derusting efficiency is an important indicator reflecting the machine's performance, which is usually expressed as the weight of steel pipes that can be derusted per hour. A medium-sized machine can derust 5-10 tons of steel pipes per hour. The surface roughness after derusting is an important factor affecting the adhesion of anti-corrosion coatings. The machine can adjust the surface roughness by changing the type and size of abrasives and the rotating speed of the blast wheels. The abrasive consumption is related to the production cost. A well-designed machine has a low abrasive consumption, usually 0.5-1.5 kg per ton of steel pipes.
Shot blasting derusting machines for steel pipe outer walls are widely used in various industries that involve the production and use of steel pipes. One of the main application fields is the construction industry, where steel pipes are used for scaffolding, pile foundations, and building structures. Derusting the outer wall of these steel pipes ensures that the anti-corrosion coating adheres firmly, extending their service life in the outdoor environment. Another important application field is the oil and gas industry, where steel pipes are used for oil and gas pipelines. The outer wall of these pipelines is exposed to harsh natural environments such as wind, rain, and sand, so effective derusting and anti-corrosion treatment are essential to ensure the safe operation of the pipelines.
In addition, these machines are also used in the water supply and drainage industry (for processing water supply and drainage pipes), the chemical industry (for processing pipes transporting chemical media), the power industry (for processing boiler pipes and steam pipes), and the automotive industry (for processing exhaust pipes and fuel pipes). For example, in the chemical industry, steel pipes transporting corrosive chemicals need to have a high-quality anti-corrosion layer on the outer wall. Shot blasting derusting removes the contaminants on the outer wall, ensuring that the anti-corrosion coating adheres well, preventing corrosion and chemical leakage.
Compared with traditional derusting methods, shot blasting derusting machines for steel pipe outer walls have numerous advantages. Firstly, high derusting efficiency. The machine can process steel pipes continuously, which is much faster than manual derusting and chemical derusting. Secondly, uniform derusting effect. The multiple blast wheels arranged around the steel pipe and the rotating movement of the steel pipe ensure that every part of the outer wall is derusted uniformly, avoiding local residual rust. Thirdly, environmental protection and energy saving. The machine uses physical derusting methods that do not produce harmful chemical waste. The dust removal system and abrasive recycling system reduce environmental pollution and resource waste. Fourthly, improving the mechanical properties of steel pipes. The work hardening effect caused by projectile impact increases the surface hardness and fatigue strength of steel pipes, enhancing their service performance. Fifthly, reducing labor intensity. Automatic operation eliminates the need for manual derusting, which is labor-intensive and inefficient, improving the working environment and safety of operators.
The operation process of a shot blasting derusting machine for steel pipe outer walls includes pre-operation inspection, feeding, parameter setting, derusting operation, unloading, and post-inspection. Before operation, operators need to inspect the machine's components, such as the blast wheels, blades, conveying rollers, dust removal system, and electrical system, to ensure they are in normal working condition. They also need to check the type and amount of abrasives and add them if necessary. Next, the steel pipes are placed on the conveying system and transported to the blast chamber. Operators then set the relevant parameters through the electrical control system, such as the rotating speed of the blast wheels, the conveying speed of the steel pipes, and the rotating speed of the steel pipes. After starting the machine, the blast wheels start to rotate, and the steel pipes enter the blast chamber while rotating. The high-speed projectiles sprayed by the blast wheels derust the outer wall of the steel pipes. During the operation, operators monitor the machine's operation status and the derusting effect of the steel pipes through the observation window. After the derusting is completed, the steel pipes are transported out of the blast chamber by the conveying system and unloaded. The outer wall of the steel pipes is then inspected. If the derusting effect meets the requirements (such as no residual rust, oxide scales, and the surface roughness reaches the specified value), they can be transferred to the coating process. If not, the parameters are adjusted, and the derusting is repeated.
Maintenance and repair of shot blasting derusting machines for steel pipe outer walls are essential to ensure their long-term stable operation and extend their service life. Daily maintenance tasks include cleaning the machine's surface and internal debris, checking the lubrication of moving parts (such as blast wheel bearings, conveying roller bearings, and reducers), and inspecting the wear of easily worn parts (such as blast wheel blades, liners, and conveying rollers). It is necessary to add lubricating oil or grease to the moving parts regularly to reduce friction and wear. Weekly maintenance includes checking the tightness of the machine's fasteners (such as bolts and nuts), inspecting the dust collection pipeline for blockages, and cleaning the dust collector. Monthly maintenance includes disassembling and inspecting the blast wheels, replacing severely worn blades and liners, checking the electrical system for loose connections and faults, and calibrating the machine's parameters. Annual maintenance includes a comprehensive inspection of the entire machine, replacing aging components, and overhauling the major systems (such as the blast wheel system and abrasive recycling system).
In addition, operators need to pay attention to some precautions during the use of the machine. Firstly, they must receive professional training before operating the machine and be familiar with the operating procedures. Secondly, they must wear personal protective equipment (such as safety helmets, goggles, and dust masks) during operation to protect themselves from injury. Thirdly, they should not overload the machine or process steel pipes that exceed the specified size range. Fourthly, they should use the specified type and size of abrasives to ensure the derusting effect and avoid damaging the machine. Finally, in case of machine failure, they should stop the machine immediately, cut off the power supply, and ask professional maintenance personnel to repair it, avoiding unauthorized disassembly and repair.
In conclusion, shot blasting derusting machines for steel pipe outer walls are important equipment in the steel pipe processing industry. Their efficient, uniform, and environmentally friendly derusting performance makes them an ideal choice for outer wall surface treatment of steel pipes. With the continuous development of various industries such as construction, oil and gas, and chemical engineering, the demand for shot blasting derusting machines for steel pipe outer walls will continue to grow. Manufacturers will continue to optimize the machine's structure and performance, developing more intelligent, efficient, and energy-saving products to meet the changing market needs. Proper operation and maintenance of these machines will ensure their maximum efficiency and service life, providing strong support for the high-quality development of the steel pipe industry.
