What Are The Key Points For Daily Maintenance Of Brazed Plate Heat Exchangers

Daily maintenance of brazed plate heat exchangers should focus on preventing blockage, corrosion, and monitoring operating status to avoid decreased heat exchange efficiency or equipment damage. There are four core points to consider. First, prevent fluid blockage. The heat exchange medium must be pre-treated (e.g., by installing a filter) to remove suspended solids and particulate impurities (particle size should be less than 1/3 of the channel diameter) to prevent impurities from depositing in the plate channels, leading to a decrease in the heat transfer coefficient. If an increase in the inlet and outlet pressure difference is found (exceeding 50% of the initial value), the unit must be shut down for cleaning. Chemical cleaning can be used (e.g., citric acid solution to remove scale, sodium hydroxide solution to remove oil stains). Direct rinsing with a high-pressure water gun is prohibited (to avoid damaging the plates). Second, control corrosion. Regularly check the pH value of the medium (avoid strong acids and alkalis exceeding the material's tolerance range). If the medium contains corrosive substances, monitor the plate corrosion (e.g., whether pitting or discoloration occurs), and add corrosion inhibitors if necessary. During periods of shutdown, the fluid inside the heat exchanger must be drained and purged with nitrogen or dry air to prevent residual medium from corroding the plates. Furthermore, monitor operating parameters, recording inlet and outlet temperatures, pressures, and flow rates weekly. If a decrease in heat exchange efficiency is detected (outlet temperature deviation exceeding 5°C), blockages or corrosion must be investigated. Avoid operation at excessive temperatures and pressures (temperature should not exceed the material's tolerance limit, and pressure should not exceed the rated value) to prevent plate deformation or leaks at brazing joints. Finally, for long-term shutdown maintenance, the heat exchanger should be stored in a dry, well-ventilated environment, avoiding direct sunlight or humid conditions. Regularly inspect the appearance of the plates; if cracks or leaks are found at brazing joints, repair them promptly to ensure the heat exchanger regains its high-efficiency heat exchange performance after maintenance.