Vahterus Plate - Recommendations for Cleaning; Backwards Flow

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5.2 Recommendations for cleaning
5.2.1 Backwardsow
In most cases loose materials such as organic compounds gathered on the surface
oftheplatescanberemovedbyinvertingtheoworthroughbackowwashingwith
warmwateroracleaningmedium.Warmwaterorcleaningmediumisushedathigh
speed on the primary and/or secondary side in the opposite direction to that of the
normal operation (approx. 2–3 times the normal velocity). The valves in the connection
pipes must be closed and the drain valves mounted on the pipelines opened. The dirty
medium must be discharged and disposed of in accordance with local requirements.
Descriptionofthebackwardsowsystem:
¬ Close valves 1.1 and 1.2. The temperature of the heat exchanger must be between
10°C and 30°C.
¬ Drainotheliquidfromthesidetobecleanedbyopeningvalve2.2.
¬ Connect a hose to valve 2.1.
¬ Watershouldowthroughtheheatexchangerfor10–15minutes.
¬ Check that organic compounds and dirt are removed.
¬ Stopthewaterow,closevalve2.1.
¬ Fill the heat exchanger with system liquid in accordance with the start-up procedure
detailed above. Close valve 2.2.
Ifthesurfaceremainsdirty,aspecicdetergentshouldbeused.
X = cleaning with chemicals
Y=cleaningwithbackwardsow
A = Vaherus heat exchanger 1 – 2 = heat or cold users or suppliers
1.1–1.4=systemshut-ovalves  3=circulatingtank
2.1–2.4=shut-ovalvesforcleaning  4=pumpforchemicals
Fig. 3 Cleaning methods