Due to unreasonable design and the use of high-moisture citric gypsum, the elevador de cangilones feeding the roller press has long experienced uneven material distribution and material sticking. Without changing the existing materials, the company’s technical staff optimized the material flow and increased material mixing uniformity. As a result, they completely resolved these issues and significantly improved the elevator’s operation.
1. Problem Description
In 2014, a company implemented an energy-saving retrofit for its cement grinding system. The cement mill has a specification of φ4.2m×13m, and the retrofit added a CLF180-140 roller press. In the original design, all materials entered the elevator through a chute, were lifted to a stabilizing bin, and then fed into the roller press.
The process flow was designed as follows:
Clinker, after batching and weighing, merged with V-separator returns in a chute.
The mixture then moved down the chute to the elevator inlet.
At the elevator inlet, it combined with batched auxiliary materials (additives and citric gypsum) before entering the elevator.
After the retrofit, severe uneven material distribution (more material on one side of the bucket) and material sticking were observed. These issues caused uneven force on the elevator chains. Over time, the chain on the heavier side stretched, while the other side remained unchanged. If not addressed promptly, this imbalance could derail the elevator’s tail pulley and disrupt operation.
2. Cause Analysis
Analysis showed that uneven material distribution resulted from the high drop height of V-separator returns. Due to inertia, these materials flowed rapidly. When they merged with auxiliary materials, the impact pushed the auxiliary flow to one side of the chute. Consequently, materials entered the elevator unevenly.
Material sticking occurred because the citric gypsum had high moisture (about 20%) and was sticky. Before entering the elevator, it did not mix sufficiently with clinker and other materials. As a result, some citric gypsum directly contacted the buckets, causing sticking.
Together, uneven distribution and sticking made one side of the buckets heavier. This uneven load stretched the chains and raised the risk of derailment.
3. Improvement Measures
Based on the analysis, the priority was to resolve uneven distribution first, then address sticking. Two improvement plans were developed:
Plan 1: Install guide plates in the chute where materials merge. These plates would change the material flow direction and reduce inertial impact.
Plan 2: Adjust and optimize material flow in the chutes. Increase vertical downward flow and reduce slanted flow to decrease inertial impact.
Plan 1 was rejected because the moist citric gypsum would likely stick to the guide plates and cause chute blockage. Therefore, Plan 2 was selected.
In Plan 2, the material flow was optimized. Cement production typically uses 10%–30% auxiliary materials and 65%–85% clinker. The original design merged clinker with V-separator returns first, then with auxiliary materials. This increased slanted flow and impact force.
4. Implementation Results
After implementing Plan 2:
About two-thirds of clinker was diverted through the new chute and mixed with auxiliary materials in advance. This mixture accounted for about 50% of the total elevator feed and flowed vertically downward.
Only one-third of clinker followed the original path and merged with system returns. The reduced flow minimized slanted impact, and materials entered the elevator evenly.
Improved mixing prevented citric gypsum from directly contacting the buckets, eliminating sticking.
Later, a rod gate valve was installed above the original clinker chute for better flow control. Currently, only about 1/10 of clinker flows through the original chute, ensuring thorough mixing and completely resolving both uneven distribution and sticking.
5. Benefits
(1) Stable Operation and Higher Efficiency
Materials now enter the elevator evenly from the center. Mixing uniformity is improved, and moist, sticky citric gypsum no longer contacts the buckets. Chains experience even force, operation is stable, and equipment utilization increased.
(2) Reduced Maintenance Costs
The improvement required:
One clinker splitter chute (2m high, 400mm x 400mm) made of 5mm steel plate with composite wear-resistant lining.
Seven rod gate valves.
Total material cost: about ¥2,000.
After the improvement:
Material mixing improved, and buckets no longer stick.
Bucket corrosion from acidic citric gypsum was eliminated.
Bucket service life extended from 2 to 4 years.
Chain life also increased significantly.
Annual savings in maintenance materials: about ¥50,000.
English 
Russian 
French 
Portuguese 
Arabic 
Spanish 
Japanese