During the critical period of transformation and upgrading of China's steel industry, the ring cooler, as the core equipment for cooling sintered ore, directly affects the "nerves" of production efficiency, energy consumption, and ecological protection through its sealing performance.

For a long time, traditional refrigeration units have relied on sand sealing, rubber sealing, and even water sealing technologies, which have always been deeply trapped in the dilemma of "serious air leakage, vulnerability and difficulty in repair, and high safety hazards". A leakage rate of 30% to 40% not only causes dust to diffuse throughout the factory area, but also forces enterprises to invest more energy costs. The scene of frequent entry and exit of workers in high-temperature and high dust areas for maintenance has become a "concern" for the safe development of the industry.

Facing Pain Points: Capturing 'Lesions' in Mud and Heat

In the deep winter of 2019, the R&D team of Northern Heavy Industries made a vow next to the circular cooling machine at a steel plant in the north, stating that it must be able to seal the wind and ensure the safety of workers' repairs. At that time, they had just endured a severe cold of -15 ℃ and waited for three days and nights to record the entire process of water seal failure caused by ice expansion - the frozen water tank support deformed, and the leaked water dripped down the gaps of the equipment, not only losing the sealing effect, but also freezing and cracking the pipes below. Three months ago at a steel plant in the south, team members once drilled into a 60 ℃ circular cooling machine, holding thermometers and anemometers to measure air leaks. When they came out, their thick work clothes could wring sweat, and the dust on the protective face mask formed a hard shell.

In order to identify the "lesions" of traditional sealing devices, the team traveled to 12 steel plants in China for three months and brought back more than 1000 sets of first-hand data: the sand seal groove repeatedly deformed due to a temperature difference of 900 ℃, and hot air infiltration accelerated steel plate corrosion; The rubber seal cannot fit properly due to the irregular elliptical trajectory of the rotating body, and it wears out and burns out in just ten days under high temperature; The problem of water seals freezing in winter and cracking after long-term use in the north has caused great suffering for many steel mills.

Sealing is not just about 'sealing gaps', it also needs to withstand temperature differences, wear and tear, and make maintenance' visible and accessible ', "said team leader Yang Yuwei.

Breaking deadlock: piecing together the 'technical puzzle' through trial error and collaboration

With the "disease list" collected on site, the team embarked on the second round of research and development - visiting more than 20 professional sealing manufacturers across the country to search for "technical fragments" that are suitable for the special working conditions of the refrigeration unit. At an automotive seal company, they found that the temperature resistance of fluoro-rubber meets the standard, but it has a lifespan of less than one month due to dust friction from the ring cooler; At a mechanical seal manufacturer, the principle of "floating compensation" impressed the team, but the existing structure cannot adapt to the circular rotation trajectory of the ring cooler.

The process of scheme iteration is a repeated struggle against failure. At the beginning of 2020, the first version of the plan drew inspiration from the water seal ring structure and used spring driven rubber seals, which can cause the rubber to harden and crack at high temperatures, dust to cause the spring to jam, and the air leakage rate is still as high as 25%; The second version introduces "composite sealing" by installing wear-resistant steel plates at the bottom of the rotating body trolley, reducing the air leakage rate to 15%. However, the radial shaking of the rotating body causes uneven wear of the seals, which need to be replaced in half a month; The team urgently visited the bearing manufacturer and integrated the "floating hinge" into the design, allowing the seal to automatically adjust the angle with shaking. However, a new problem was discovered by workers during maintenance - the equipment was not completely cooled during repair, and workers still had to drill into the equipment to replace components in a high temperature environment of 70 ℃, without reducing the safety risk at all.

At the end of 2021, the fourth version of the plan finally achieved a key breakthrough. On the basis of retaining the dynamic adaptation advantages of "composite materials + spring compensation", the R&D team moved the core sealing components to the outside of the ring cooler and designed a detachable maintenance window. During on-site testing, workers only need to stand on the ground to open the window and replace the seal, without the need to drill into high-temperature equipment.

Implementation effectiveness: from technological breakthroughs to green production

With the successful authorization of multiple patents such as "a floating mechanical seal device for a ring cooling machine" and "a high-quality and efficient sintering ring cooling machine", the innovative achievements of Northern Heavy Industry have taken root in the industry.

In large-scale sintering projects such as Jinan Iron and Steel and Tangshan Ganglu, the annular cooling machine equipped with this device has demonstrated astonishing efficiency: the air leakage rate has dropped sharply from the traditional 30% ~ 40% to 5%~10%, dust emissions have been reduced by nearly 80%, and the air quality around the factory area has significantly improved; The equipment failure rate has decreased by 60%, the frequency of shutdown and maintenance has been significantly reduced, and the number of times workers enter high-temperature and high dust areas has been reduced by 90%. The safety of operations has been effectively guaranteed; There is no need to increase the installed capacity of the fan, and a single ring cooling machine can save over one million yuan in electricity bills annually, providing strong support for enterprises to reduce costs and increase efficiency.