Problem

Deformation is one of the most common issues in 10T–30T rotomolded water tanks. Users often notice bulging walls, bending or bottom sinking after installation or long-term use. This issue becomes more significant as tank size increases and structural stress becomes higher.

Why It Happens

Deformation is usually caused by multiple combined factors. Improper height-to-diameter ratio reduces structural stability. Uneven wall thickness creates weak areas. Continuous hydrostatic pressure applies long-term stress on the tank. Temperature variation causes expansion and contraction. Internal stress from uneven cooling further affects structural performance. These effects become more obvious in large tanks.

Technical Insight

Rotomolded tanks rely entirely on geometry and wall thickness for strength. Large tanks with diameters up to 3150mm and heights above 3000mm require well-balanced design. Flat walls and weak bottom structures increase deformation risk. In addition, unstable temperature or rotation can cause uneven material distribution.

Solution

To reduce deformation risk, design optimization must start at the mold stage. Maintain a balanced height-to-diameter ratio. Add reinforcement ribs or corrugated structures to improve rigidity. Strengthen bottom areas to support liquid weight. Optimize mold geometry to ensure uniform material distribution. For large tanks, structural reinforcement is more effective than simply increasing size.

Process Control

Stable process parameters are essential. Temperature should be controlled within ±2°C. Rotation speed is recommended at 3–6 rpm. Heating time usually ranges from 40 to 60 minutes depending on size and thickness. Stable processing reduces wall thickness variation.

Material and Thickness Strategy

For 10T–30T tanks, wall thickness is typically 10–15mm. Critical areas should be locally reinforced. Excessive thickness should be avoided because it may cause uneven cooling and internal stress. Balanced thickness design ensures strength and stability.

Application-Based Design

Agricultural applications focus on weather resistance. Industrial applications require higher structural stability. Chemical storage requires higher safety factors. Mold design should be based on real application conditions.

Conclusion

Deformation is caused by the combined effect of structure, thickness and process. Proper design and control are essential to achieve long-term performance.