PVC Covered Spiral Steel Pipes

1. Definition

PVC covered spiral steel pipes are flexible or semi-rigid pipes constructed from a spiral-wound steel wire or steel strip core that is externally coated or fully encapsulated with PVC (Polyvinyl Chloride). The steel spiral provides mechanical strength and shape retention, while the PVC covering offers protection, flexibility, and resistance to environmental factors.

These pipes are widely used in ventilation, air handling, dust extraction, industrial suction, and cable protection applications.

2. Construction Structure

PVC covered spiral steel pipes typically consist of three main components:

1. Spiral Steel Reinforcement

   • Made from galvanized steel wire or steel strip

   • Provides structural strength and collapse resistance

   • Maintains round shape under vacuum or pressure

2. PVC Covering / Coating

   • Flexible PVC layer bonded to the steel spiral

   • Can be transparent or opaque

   • Protects against moisture, corrosion, and chemicals

3. Inner Lining (Optional)

   • Smooth PVC interior for improved airflow

   • Reduces friction, dust buildup, and pressure loss

3. Key Characteristics

• High flexibility: Can bend without losing shape

• Mechanical strength: Steel spiral resists crushing and vacuum collapse

• Corrosion resistance: PVC protects steel from rust and chemicals

• Lightweight compared to solid steel pipes

• Smooth airflow performance

• Durable and long service life

4. Common Applications

PVC covered spiral steel pipes are used in many sectors, including:

• HVAC ventilation and exhaust systems

• Industrial dust and fume extraction

• Woodworking and CNC machine suction lines

• Chemical and pharmaceutical plants

• Agricultural grain and feed transfer

• Cable and wire protection conduits

• Laboratory air and gas handling systems

5. Advantages

• Easy and fast installation

• Reduced maintenance needs

• Resistant to humidity and harsh environments

• Cost-effective compared to rigid metal ducting

• Can be supplied in long lengths, reducing joints and leaks

6. Limitations

• Not suitable for very high temperatures

• Fire resistance depends on PVC grade (standard PVC is combustible)

• Lower pressure rating compared to rigid steel pipes

7. Comparison with Other Pipe Types

8. Summary

PVC covered spiral steel pipes combine the strength of steel with the flexibility and protection of PVC, making them an ideal solution for applications that require durability, corrosion resistance, and ease of installation. They are especially effective in industrial and ventilation systems where both flexibility and mechanical performance are essential.