How to Clean a Plate Heat Exchanger: CIP and Mechanical Cleaning

Fouling on the plate surface reduces heat transfer and increases pressure drop. Both effects raise pumping energy and reduce plant output long before the unit visibly fails. A regular cleaning programme keeps the unit at clean-baseline performance and extends gasket and plate life. Wait until performance has dropped sharply and the deposits may be too hard to remove without opening the unit.

Trigger cleaning on measured performance — not the calendar. Track pressure drop and approach temperature against the clean baseline. When pressure drop rises 30–50% above baseline, or when the approach temperature widens beyond design, schedule a CIP. Highly fouling services (cooling tower water, dairy, wastewater) may need monthly cleaning; clean utility services can run a year or more between cleans.

CIP cleans the plates without opening the unit. Isolate and drain the side to be cleaned, then circulate cleaning chemistry through a CIP loop. Typical cycle: rinse with water, circulate caustic (1–2% NaOH) at 70–80 °C for 30–60 minutes to remove organic deposits and biofilm, water rinse, circulate acid (1–2% nitric or 2–5% phosphoric) at 60–70 °C for 30–60 minutes to remove scale and metal-oxide deposits, final water rinse to neutral pH. Use velocities of 0.3–0.5 m/s through the channels to lift loosened deposits.

Calcium and magnesium scale: nitric or phosphoric acid. Organic fouling and biofilm: caustic, often with a surfactant. Iron oxide and corrosion deposits: phosphoric or citric acid with a chelating agent. Protein deposits (dairy, food): caustic first to break down, then acid to remove minerals. Always confirm chemistry compatibility with the plate material and gasket compound — strong oxidising acids attack titanium gaskets and stainless plates differently.

When deposits are too hard or too thick for CIP, open the unit and clean each plate. Drain and depressurise fully, loosen the tie-bars evenly, slide plates apart on the carrying bar. Clean each plate with low-pressure water (max 50 bar) and a soft brush. Never use wire brushes, steel scrapers or abrasive pads — they scratch the plate surface, shorten gasket life and create future fouling sites. For very stubborn deposits, soak individual plates in cleaning chemistry before brushing.

Inspect every gasket during reassembly — replace any that are cracked, swollen or compression-set. Stack plates in the original orientation (follow the arrows on the plate edge). Tighten the tie-bars evenly across all four corners to the nameplate plate-pack dimension. Never tighten beyond the nameplate value — over-tightening distorts plates and crushes gaskets. Pressure-test before returning to service.

Cleaning chemistry is hazardous: wear chemical PPE, isolate and tag the unit, ventilate the area. Spent cleaning solutions must be neutralised and disposed of according to local environmental regulations. Document each clean — date, chemistry, temperature, duration, pre- and post-cleaning pressure drop — so the cleaning programme can be optimised over time.

Jiangxing supplies replacement gaskets and plates for our own gasketed plate heat exchangers and many common third-party models. Send the unit nameplate or a photo of the gasket profile to Evan at jxmike@shheatex.com and we'll confirm compatibility and pricing.