Can Double Wall PHEs Be Chemically Cleaned?
Double wall plate and frame heat exchangers (PHEs) are designed to prevent cross-contamination, making them essential for applications like potable water, food processing, and pharmaceuticals.
A common question is: Can double wall PHEs be chemically cleaned?
Yes, double wall PHEs can be effectively cleaned using chemical flushing or Clean-in-Place (CIP) methods, as confirmed by industry leaders like Heat Exchanger Ontario, ensuring efficiency and safety when performed by professionals.
What Are Double Wall PHEs?
Double wall PHEs feature two plates between fluid channels, providing a failsafe against leaks and cross-contamination, as noted by T.H. Industrial Solutions. This design ensures that if a plate develops a pinhole or crack, fluids remain separated, critical for potable water systems under municipal codes.
How Are Double Wall PHEs Chemically Cleaned?
Chemical cleaning methods for double wall PHEs include:
- Clean-in-Place (CIP): Alfa Laval and Hofmann Heat Exchanger endorse CIP systems, which circulate non-toxic cleaning solutions like citric acid or Alfa P-Scale (sulphamic acid-based) to dissolve scale, for organic deposits like fats or biofilms, without disassembly.
- Chemical Flushing: Heat Exchanger Ontario uses portable units with pumps and filters to circulate mild acid or citrus-based solutions for 6–8 hours, effectively removing debris, though less effective for hardened scale.
- Post-Cleaning Rinse: After circulation, clean water flushes out residual chemicals and debris, followed by neutralization (e.g., using Alfa P-Neutra), ensuring environmental compliance.
Effectiveness of Chemical Cleaning
Chemical cleaning is highly effective for double wall PHEs because it:
- Removes Fouling: Dissolves calcium carbonate, rust, and organic matter, restoring heat transfer efficiency and reducing pressure drops (7–10 psi indicates cleaning need), per T.H. Industrial Solutions.
- Maintains Safety: Preserves the double wall’s protective barrier, critical for potable water
- Minimizes Downtime: CIP cleaning, as offered by Hofmann Heat Exchanger, takes 6–8 hours without disassembly, ideal for food and pharmaceutical applications.
Limitations and Considerations
- Hardened Scale: Severe fouling may require combining chemical cleaning with high-pressure water jetting
- Material Compatibility: Chemicals must be compatible with plates (e.g., stainless steel) and gaskets to avoid corrosion
- Environmental Compliance: Spent chemicals must be neutralized and disposed of per regulations
- Professional Expertise: Services from T.H. Industrial Solutions ensure proper chemical selection and flow rates (e.g., 1 ft/sec).
When to Chemically Clean Double Wall PHEs
Chemical cleaning is recommended every 5–6 years or when differential pressure reaches 7–10 psi, indicating fouling. It’s ideal for routine maintenance in potable water or food systems, ensuring compliance with safety codes.
Conclusion
Double wall PHEs can be chemically cleaned using CIP or chemical flushing, effectively removing fouling while maintaining their anti-contamination design. Industry leaders like T.H. Industrial Solutions offer expert services to ensure efficiency and safety.
