When should purified water equipment be cleaned?

It is normal for the purified water equipment to have a gradual decline in the water production after a period of application, mainly due to the pollution of the reverse osmosis system.
At this time, in order to ensure the qualified water quality and restore the expected water production, it must be cleaned, then the purification When do water equipment need to be cleaned? How to clean it? When any of the following situations occurs in the purified water equipment, it needs to be cleaned in time: 1.
Under normal water supply pressure, the water production is reduced by 10-15% compared with the normal value; 2.
In order to maintain normal water production, the normal value decreases after temperature correction 10-15%; 3.
The quality of the produced water decreases by 10-15%, and the salt permeability increases by 10-15%; 4.
The water supply pressure increases by 10-15%; check this parameter)
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The following six steps are generally taken for cleaning purified water equipment: 1.
Preparation of cleaning solution Add the chemicals into clean water, and the preparation water must be RO product water or deionized water that removes hardness and does not contain excessive metals and residual chlorine
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Make sure the solution is thoroughly mixed and adjust the temperature and pH to the desired values
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2.
Input the cleaning liquid at low flow rate.
First, mix the cleaning liquid with the cleaning pump.
When preheating the cleaning liquid, the flow rate should be low
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Then, the raw water in the element is replaced with the lowest possible cleaning fluid pressure, and the pressure only needs to be sufficient to supplement the pressure loss of the feed water to the concentrated water, that is, the pressure must be low enough not to produce significant permeate water
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The low pressure replacement operation can minimize the re-precipitation of fouling on the membrane surface.
Depending on the situation, part of the concentrated water is discharged to prevent the dilution of the cleaning solution
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 　　3.
Circulation When the raw water is replaced, the cleaning liquid should appear in the concentrated water pipeline, so that the cleaning liquid is circulated back to the cleaning water tank and the temperature of the cleaning liquid is kept constant
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 　　4.
Immersion Stop the operation of the cleaning pump and allow the membrane element to be completely immersed in the cleaning solution
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Sometimes 1 hour soaking of components is sufficient, but for stubborn contaminants, it is necessary to extend the soaking time, such as soaking for 10 to 15 hours or soaking overnight
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In order to maintain the temperature of the soaking process, very low circulating flow rates can be used
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 　　5.
When the high-flow water pump circulates under high-flow conditions, there will be a problem of excessive pressure drop.
The maximum allowable pressure drop for a single element is 1bar (15psi), and the maximum allowable pressure drop for a multi-element pressure vessel is 3.
5bar (50psi).
whichever is exceeded first
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 　　6.
Rinse: Use clean water (RO product water or deionized water that removes hardness and does not contain metal ions such as iron and chlorine) for low-pressure flushing.
The cleaning solution in the flushing system can be pretreated with qualified product water unless there is a corrosion problem.

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To prevent precipitation, rinse at 20ºC
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 　　The above is an introduction to the judgment of the pollution of purified water equipment and the cleaning method.
It is recommended that users find professional and technical personnel to guide the cleaning to avoid incorrect operation leading to incomplete cleaning
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