During the operation of the screening production line, the feed rate of the square gyratory screen fluctuates frequently, resulting in an inconsistent material layer thickness on the screen surface. Sometimes, an excessively thick material layer leads to "submerged" screening, preventing fine particles from passing through the screen in time; other times, interruptions or insufficient feed result in inadequate screen utilization, causing "empty runs." This unstable state directly causes continuous fluctuations in screening efficiency and product precision, ultimately affecting the consistency of finished product quality. In severe cases, uneven loads may even trigger overload alarms on the screen motor and abnormal equipment vibration.

Cause Analysis:

1. Feeding Equipment Capacity Imbalance: The rated conveying capacity of the upstream feeder (such as a screw conveyor or vibrating feeder) is mismatched with the optimal processing range of the gyratory screen, or the equipment's own speed regulation is unstable, failing to provide a constant flow rate.

2. Obstructed Material Flow within the Bin: Design flaws in the preceding bin, such as an excessively small cone angle or rough inner walls, can cause powder or granular materials to easily form "bridging" (arching) or "rat hole" effects, resulting in intermittent discharge.

3. Lack of buffering and adjustment units: In the production line layout, the outlet of the hopper and the inlet of the gyratory screen are rigidly and directly connected, lacking a buffer device to smooth out flow peaks and troughs, thus failing to absorb fluctuations in upstream material.

4. Isolated control logic: The feeding equipment and the gyratory screen are controlled independently, failing to form a feedback adjustment closed loop based on the actual screening load, and the system cannot automatically respond to changes.

Systematic Solutions:

1. Precise Matching and Upgrade Selection

- Capacity Verification: Recalibrate the process flow rate to ensure the rated capacity of the selected feeding equipment is slightly higher than the optimal throughput of the gyratory screen, and prioritize models with continuous speed regulation.

- Handling Difficult-to-Flow Materials: For materials prone to moisture absorption and arching, select silos equipped with active arch-breaking devices (such as silo wall vibrators or fluidizing air cushions) and pair them with forced feeders (such as screw feeders with stirring shafts).

2. Optimizing Material Interface and Buffer Design

- Silo Modification: Increase the discharge cone angle of the silo or use a smooth lining (such as ultra-high molecular weight polyethylene sheets) to significantly reduce material adhesion and promote overall flow.

- Adding Buffer and Feedback Elements: Add a small buffer hopper between the silo and the gyratory screen and install a level sensor. Through simple feedback control (such as accelerating feeding at low levels and decelerating or stopping feeding at high levels), stabilize the primary flow rate and effectively "shaving peaks and filling valleys."

3. Implementation of Intelligent Linkage Control

- Basic Interlocking: In electrical control, a sequential interlock is implemented where "the feeder can only start after the screening machine starts; the screening machine can only stop after the feeder stops," preventing misoperation.

- Advanced Closed-Loop Control: A PLC control system is introduced, using real-time material level signals from the buffer hopper and even the load current signal of the gyratory screen drive motor as core parameters to dynamically adjust the feeder's frequency converter speed. This achieves fully automatic and highly stable control of the feed rate, ensuring the screening machine always operates at its optimal load.

Through the above systematic matching, modification, and upgrades, the front-end material supply can be stabilized from the source, creating continuous and balanced working conditions for the square gyratory screen, thereby ensuring stable screening efficiency and product quality throughout the entire production line.

Clearly Separated Particles, Intelligent Screening -- Mirant Xinxiang Machinery Equipment Co., Ltd.