Why do the ball joints of dredging pump systems leak?

Leakage Cause Analysis

The leakage problem of dredging pump ball joints can be analyzed from four main aspects: the condition of the sealing components, installation and commissioning, stress environment, and media characteristics.

1. Wear and Aging of Sealing Components

Long-term wear from high-pressure media: The ball joint is constantly exposed to high-pressure environments of 1 MPa to over 3 MPa.  The long-term friction between the sealing components and the pipe wall leads to wear and hardening of the packing or O-rings, reducing sealing performance and causing leakage.

Media erosion: The mud slurry may contain corrosive components or fine sand particles, which, over time, can erode the metal surface, causing fine cracks in the flange surface or welds, becoming a potential source of leakage.

2. Installation and Commissioning Problems

Misalignment: The connecting surfaces of the ball joint are not aligned (e.g., the flange is not perpendicular), or the pipeline installation angle is incorrect, resulting in uneven stress at the connection point and causing leakage.

Insufficient bolt tightening: In high-pressure or vibrating environments, the connecting bolts may loosen, increasing the gap at the connection point and causing leakage.

3. Stress and Environmental Influences

High-pressure shock: Water hammer effects during pump start-up or shutdown can generate instantaneous high-pressure shocks, damaging the sealing surface at the joint and causing leakage.

Uneven stress: Dredging vessels may encounter unbalanced loads or hull movement during operation, leading to uneven stress on the joint and permanent deformation of the sealing components.

4. Sealing Structure Design Defects

Unreasonable gland design: If the clamping force of the sealing gland is insufficient, or the gland material is not suitable for high-temperature and high-pressure environments, the sealing surface cannot maintain tight contact, leading to leakage.