Plate heat exchangers are extensively used in industries such as central heating, food processing, machinery, metallurgy, petrochemicals, and marine applications. They have become a cornerstone of urban central heating systems due to their efficiency and reliability. However, ensuring their optimal performance and extending the lifespan of key components requires a clear understanding of potential failures, their causes, and appropriate solutions.
One common issue is a large pressure drop within the heat exchanger. Here’s an overview of the problem, its causes, and effective treatment methods.
What is a Large Pressure Drop?
A large pressure drop occurs when the pressure difference between the media inlet and outlet exceeds design specifications, often by significant margins. This can severely disrupt the system’s flow and temperature requirements.
In heating systems, excessive pressure drops on the hot side can lead to insufficient primary-side flow, causing inadequate heat transfer. As a result, the secondary-side outlet temperature may fail to meet operational requirements, impacting overall system efficiency.
Causes of Large Pressure Drops
Several factors can contribute to excessive pressure drops in plate heat exchangers:
- Debris in the System:
Newly installed piping systems may contain contaminants like welding slag, dirt, or gravel. These can enter the narrow flow channels (2–5 mm) of the heat exchanger, leading to blockages at the corner holes or inflow areas. - Improper Initial Selection:
Selecting a heat exchanger with insufficient area can cause excessively high flow rates between plates, increasing the pressure drop. - Scaling and Fouling:
Over time, scaling on plate surfaces or accumulation of sediment can significantly reduce flow channel area, resulting in increased pressure loss. - Unsuitable Media:
Heat exchange media containing large particles or fibers can easily block the narrow channels between plates.
Treatment Methods
To address large pressure drops, specific solutions are recommended based on the underlying causes:
- Routine Cleaning:
For newly installed systems, perform regular cleaning (e.g., weekly) to remove dirt and debris. - Chemical Cleaning:
Use a specially formulated cleaning solution at 40–60°C for chemical cleaning without disassembly. Cleaning ports installed on the media inlet and outlet can facilitate this process. After cleaning, flush the system thoroughly with water to ensure the pH is neutral (≥7). - Manual Cleaning:
When disassembly is required, soak the plates in a cleaning solution for 30 minutes, then gently brush the scale using a soft brush before rinsing with water. Take care to avoid damaging the plates or rubber gaskets.
Conclusion
Understanding the causes and implementing proper maintenance measures is essential for preventing pressure drops in plate heat exchangers. By proactively addressing these issues, users can ensure optimal system performance, reduce downtime, and extend the lifespan of their equipment.
Regular maintenance and timely interventions are the keys to maximizing the efficiency and durability of your plate heat exchanger.
