When the sealing technology of the circular cooler solves the "green challenge" in the iron and steel industry, the R&D focus of Northern Heavy Industries has turned to bulk material handling equipment. In the heavy equipment market, foreign enterprises have long monopolized the core technologies of large-span gantry scraper reclaimers, and models with a span of over 60 meters have even been the "exclusive domain" of foreign companies. Taking independent innovation as its spear, Northern Heavy Industries, relying on the invention patent of "The Four-Link Mechanism for Scraper Reclaiming Devices with Connecting Rod as the Driving Component", not only overcame the technical difficulties of the 65-meter ultra-span reclaimer but also achieved the leap in technology from "following" to "leading".

The "Impossible Mission" of the 65-Meter Reclaimer

In the summer of 2020, Northern Heavy Industries signed the contract for the stacker-reclaimer of the Philippine MPGC project, which was almost an "impossible task" — it required designing and manufacturing an intelligent fully-enclosed coal yard stacker-reclaimer with a large span of 65 meters, full explosion-proof function and multi-machine common rail system for the project.

Back then, some multinational corporations, relying on technological barriers, firmly held the core technologies of large-span gantry scraper reclaimers in their hands. In traditional equipment, the main and auxiliary scrapers were hinged as one unit; the auxiliary scraper could only follow passively and could not intelligently adjust its downward penetration depth according to the height and fluidity of the material pile, leading to frequent "material backflow".

With an ultra-long span of 65 meters, the end beam of the auxiliary scraper was suspended high. It needed not only to scrape the bottom-layer materials accurately but also to be completely lifted away from the material pile when not in operation. Changes in the material repose angle, mechanism stability, material strength... Each of these was a steep peak standing in the team's way. "If foreign enterprises can do it, why can't we?" Behind this question lay Northern Heavy Industries' unyielding fighting spirit.

"The Four-Link Mechanism" Illuminates the Light of Independent Innovation

"Back then, we reviewed thousands of research papers and visited experts at home and abroad, only to find that this technical problem was almost unsolvable," said the head of the R&D and breakthrough team at Northern Heavy Industries. Faced with technological blockades by foreign enterprises and gaps in the industry, independent innovation was the only way to break the monopoly.

In the early stage of R&D, the complex coupling between material parameters and mechanical movement made the design of the auxiliary scraper's operation trajectory a major "obstacle". Countless late nights saw the laboratory brightly lit, with design drawings piled up like mountains and calculation data vast as the sea. The team reviewed thousands of papers, carried out hundreds of program iterations, and after dozens of rounds of optimization, an inspiration struck — the introduction of a four-link mechanism. Its movement trajectory is precisely controllable, force transmission is efficient and direct, and it can skillfully eliminate rigid impacts.

The design required precise avoidance of the four-link mechanism's "deadlock zone" and repeated optimization of rod parameters based on the material repose angle and hinge point positions. After days of continuous intense work, a finalized plan was finally achieved. In 2022, good news came from the site of a project in Southeast Asia: after 8 months of rigorous operation, this set of large-span, fully explosion-proof, and intelligent stacking and reclaiming system won verification with its outstanding performance.

From "Chinese Wisdom" to "Chinese Standards"

On September 24, 2024, the National Intellectual Property Administration of China officially granted Northern Heavy Industries the invention patent for "The Four-Link Mechanism for Scraper Reclaiming Devices with Connecting Rod as the Driving Component". According to the patent document, this four-link mechanism is formed by hinging the inclined section of the gantry, the first connecting rod, the second connecting rod and the auxiliary scraper reclaiming device. With the connecting rod serving as the driving component, the auxiliary scraper can operate independently — this not only avoids interference with the main scraper, but also flexibly adjusts the reclaiming depth according to material properties, significantly improving the intelligence level and energy efficiency ratio.

Today, this technology has been applied in multiple industries such as iron and steel, cement, and coal. The independent control of the auxiliary scraper allows flexible start and stop based on the progress of the main scraper, while the staggered operation of the two scrapers ensures "complete material clearance from the bin" and a significant reduction in energy consumption.

Forge New Heights of "Made in China 2.0" with Great Craftsmanship

From the circular cooler sealing device safeguarding the "green development" of the iron and steel industry to the four-link mechanism breaking international monopoly, Northern Heavy Industries' core patents are applied in different fields but share the same innovative core — being customer demand-oriented and solving problems through independent R&D. As the Chief Engineer of Northern Heavy Industries put it: "A patent is not only a reflection of technological achievements, but also a moat for an enterprise's core competitiveness."

Currently, Northern Heavy Industries has built a full-chain technology protection system covering R&D, production, and services. In the field of circular coolers, the team is actively exploring the performance optimization of new metal matrix composites under extreme high temperatures and attempting to integrate bionics principles into the sealing structure. In the field of bulk material handling, the team continues to deepen the intelligent upgrading of the four-link technology, promoting equipment towards "zero failure" and "maintenance-free" operation. Meanwhile, the enterprise strengthens in-depth cooperation with domestic and foreign universities and scientific research institutions, taking "high-end, intelligent, and green development" as the main line to contribute to the comprehensive revitalization of Liaoning Province.