How to Avoid Dredging Pipeline Blockage ?

In dredging operations, the slurry pipeline system serves as a critical conduit connecting dredging equipment to material deposition areas, with its operational status directly impacting overall productivity. Although pipeline blockages are a common issue, they can lead to severe consequences such as unexpected shutdowns, sudden drops in production, and soaring maintenance costs. Accurately understanding the causes of blockages and mastering effective countermeasures are essential for ensuring the continuity and cost-effectiveness of dredging operations

Pipe blockages are rarely caused by a single factor but are usually the result of multiple conditions overlapping. Common causes include:

• Insufficient flow rate: The slurry flow rate is lower than the critical settling velocity of the material, causing solid particles to deposit at the pipe bottom and gradually accumulate
• Strong material adhesion: High clay or plastic slurry increases adhesion to the pipe wall, easily forming a viscous deposit layer
• Foreign object ingress: Large particles or fragments entering the pipeline, exceeding its designed conveying capacity
• Poor pipeline layout: Sharp bends, sagging sections, or hose collapse increase local flow resistance and accelerate sedimentation

When the above conditions coexist, sediments will accumulate rapidly, ultimately leading to partial or complete blockage.

Early detection is key to minimizing losses. Operators should closely monitor the following operational indicators:

• Abnormal pressure: The discharge pressure of the dredging pump rises significantly, while the suction vacuum pressure at the pump inlet decreases
• Load variation: The engine load decreases under continuous pumping conditions

High-frequency blockage locations include pipe diameter transition sections, submerged pipe sections, crossings, and sagging floating pipelines. These symptoms are particularly pronounced when dredging coarse particles, plastic clay, or mixed soil, requiring focused monitoring.

In case of suspected blockage, immediate systematic action should be taken:

1. Adjust the work parameters
   • Pause lateral movement
   • Lifting bridge rack
   • Reduce the slurry concentration
   • Increase the pump speed to stabilize the water output pressure
2. Line inspection
   If the adjustment proves ineffective, immediately inspect each section along the pipeline route, locate the blocked segment, and assess its severity.
3. Mechanical Removal
   If the adjustment fails, disconnect the affected pipe section and manually remove the blockage.

Long term stability depends on reasonable design and standardized operation, with key points including:

• Flow rate control: Maintain the flow rate in the pipeline above the critical settling velocity of the material. The critical flow rate is influenced by factors such as particle size and pipeline diameter. The larger the particle size and diameter, the higher the required critical flow rate
• Optimize layout: Keep the pipeline as straight as possible to avoid sharp bends and hose collapse. In floating or flexible connection sections, using JIUBEI dredging hoses with smooth inner walls and cooperating with floating bodies can effectively prevent local retention caused by hose collapse
• Regular inspection: Pay special attention to the transition section and bottleneck points of the pipe diameter, ensuring that their diameter is greater than the spacing between the feeding grids
• Concentration management: Strictly control the slurry concentration when dredging large particles or plastic clay, especially to prevent flow interruption caused by sudden pump shutdown.