At one cement plant, the waste heat recovery boiler at the kiln inlet (SP boiler) was experiencing a recurring issue. During operation, the rapping mechanism – designed to clean the boiler tubes – frequently broke the clips that transmit the rapping force. These broken clip fragments then fell into the return ash. The question was: how could these metal fragments be effectively separated from the ash at the bottom of the boiler?
Engineer Mr. Zhang offered a simple yet ingenious solution.
At this cement plant, the clinker production line is equipped with a waste heat recovery boiler at the kiln inlet (SP boiler). The boiler generates a large amount of return ash during operation, which is transported via a drag chain conveyor and a bucket elevator to the homogenization silo. To keep the boiler tube surfaces clean and ensure efficient heat transfer, the SP boiler is equipped with a rapping mechanism that intermittently strikes the tubes. However, while this mechanism successfully knocks off ash deposits, it often causes the clips that transmit the rapping force to break and fall into the ash.
Given that each SP boiler contains thousands of such clips, any metal fragments entering the system pose serious risks to downstream equipment – including feed scales, air slides, various valves, and rotary airlocks. In severe cases, this can even lead to unscheduled kiln shutdowns.
To address this, Engineer Mr. Zhang proposed a custom‑designed "drawer" specifically intended to trap broken clip fragments. The drawer features a 20×20 mm grid at the bottom, a sealing felt at the end cap, and quick‑locking devices on both sides. It is installed on the material pipe leading from the rotary airlock at the boiler bottom to the drag chain conveyor.
In operation, the rotary airlock is temporarily stopped. The drawer is unlocked, pulled out, and any broken clip fragments are removed. The drawer is then pushed back in, locked in place, and the rotary airlock is restarted. By performing this simple check at regular intervals, all metal fragments can be removed – completely eliminating the risk of damage to the homogenization silo and even the kiln system.
A small "drawer" that solves a big problem – another smart, practical solution from the field.
