What are some common mistakes that shorten the lifespan of plate heat exchangers?

I. Cleaning Operation Errors (The Most Common Cause of Shortened Lifespan)

1. Using strong acids such as industrial hydrochloric acid or nitric acid to soak the plates will directly corrode the 304 stainless steel plates. Long-term use can easily cause pitting corrosion and perforation. Even if the passivation layer is damaged once, the subsequent corrosion rate will be greatly accelerated.

2. Soaking for excessively long periods will damage the passivation layer on the plate surface and the molecular structure of the sealing gaskets, causing the gaskets to lose elasticity prematurely and leading to leakage problems.

3. Using high-temperature + high-alkali cleaning methods, where the water temperature exceeds 60℃, will cause the gaskets to age and deform rapidly. Many devices will experience "leaking immediately after cleaning."

4. Vigorously scrubbing the plates with steel brushes or hard-bristled brushes will scrape off the anti-corrosion protective layer on the plate surface. The invisible scratches left behind will become the starting point for pitting corrosion and will also damage the contact surface of the sealing gaskets.

5. Directly spraying the plates with a high-pressure water gun will damage the surface coating and cause corrugation deformation, which will actually exacerbate scaling and corrosion.

II. Bolt Maintenance Errors: After a period of operation, bolts may loosen. Many people arbitrarily tighten them, leading to uneven stress on the bolts. This can cause gasket displacement, plate misalignment, and leaks. Uneven stress on the plates can also cause localized deformation, shortening their lifespan.

III. Water Quality Management Errors:

1. Directly using untreated hard water or wastewater into the heat exchanger will cause calcium and magnesium ions to quickly form scale, clogging the flow channels and increasing the risk of plate corrosion. Sediment, rust, and other impurities in the water will also clog pipes, physically wear down the plate surface, and accelerate equipment aging.

2. Failure to monitor and soften water quality over a long period will lead to the continuous accumulation of scale and impurities. This not only reduces heat exchange efficiency but also requires frequent cleaning, adding extra wear with each disassembly and reassembly.

IV. Installation Operation Errors:

1. Failure to reinstall plates with misalignment exceeding the allowable threshold (more than 10mm for small plates, more than 5% of the side length for large plates) will cause flow channel blockage, uneven stress on the sealing surface, and plate bending. Long-term operation will result in cracks, directly shortening the plate's lifespan.

2. Incorrect plate installation orientation leads to mismatched corrugation patterns, uneven gasket compression, and over- or under-compression in some areas. This easily causes leaks during operation and can also disrupt flow channels, accelerating plate and gasket aging over time.

3. Adjacent plates installed in the same direction but not stacked 180° in opposite directions create dead zones in the flow channels, exacerbating localized scaling and corrosion, reducing heat exchange efficiency, and shortening equipment lifespan.

V. Other Common Errors

1. Long-term operation exceeding design parameters: Operating at temperatures and pressures exceeding the equipment's rated parameters accelerates gasket aging and plate corrosion, shortening lifespan by approximately 30%.

2. Frequent equipment start-ups and shutdowns: Frequent daily start-ups and shutdowns subject the plates to repeated stress from thermal expansion and contraction, accelerating mechanical fatigue by 25% and increasing the likelihood of leaks and deformation.

3. Long-term inactivity without maintenance: Failure to clean the plates or perform rust prevention during idle periods leads to plate corrosion and natural gasket aging, making malfunctions more likely upon reuse.

4. Failure to perform regular preventative maintenance: Only addressing issues after a malfunction occurs allows small problems to gradually escalate into major damage. For example, if a minor leak is not addressed promptly, it will continue to corrode the edges of the board, eventually leading to the board becoming unusable.