Why the sand filer and active carbon filter is leaking water

Several times when foreign customers asked Haiyuan to quote for quartz sand and activated carbon filters, they emphasized the quality problem, because the filter vessel they bought from other suppliers before have leaked water and they showed some photos.

As the surface of the activated carbon filter vessel  is corroded, there is water leakage.

Based on Haiyuan past experience, the rules can be summarized as below:

1. Corrosion mostly occurs in the activated carbon filter vessel, while for sand filter vessel generally will not be leaked.

2. The corrosion mostly occurs in the welded seam or the weak part of the filter vessel.

3. The corrosion usually appears after a few months of operation.

4. The corrosion occurs randomly.

Because similar phenomena have occurred in different countries and regions, experts have conducted field inspections, tests, and analyses, and concluded that strong oxidants have caused corrosion of the tank.

The sources of oxidants mainly from as below:

1. The water contains oxidizing substances that exceed the corrosion resistance of stainless steel filter vessel, but the water quality report does not detect strong oxidizing substances in it.

2. The strong oxidants (such as chlorinated fungicides) added in the previous or existing process are not treated.

3. Welding is not qualified.

4. Other unidentified factors.

The reason why the activated carbon filter vessel is easy to corrode is because the activated carbon will adsorb the oxidant and accumulate filter vessel; then after long-term operation the welded seam and other weak points of the filter vessel will be completely corroded to cause the leakage.

Solutions offered by Haiyuan:

1. If strong oxidizing substances are added tin the previous or existing process, stop adding or add corresponding reduction treatment

2. Replace with more corrosion-resistant and thicker stainless steel plates to make quartz sand and activated carbon filter vessel

3. The material should be thick and the weld seam should not be ground,  if the weld seam is too thin, when the system starts the cover on the top of the tank will bulge due to pressure in operation, and the system stops and the cover will fall, the weld seam will become thinner if it is flattened, then and the chloride ions adsorbed by activated carbon will be more likely to corrode the weld and cause water leakage.

Sometimes the water quality report provided by the customer does not detect excessive oxidants, but the objective existence of corrosion indicates that there are undetected oxidizing substances.

Therefore, in order to avoid water leakage, please provide the water quality report containing the detected oxidant factor or inform if the oxidizing substances are added during previous or existing process, then Haiyuan will provide you the filters with the finest quality to best fit your demand.

Possible causes of rust:

The water contains oxidizing substances beyond the corrosion resistance of 304 stainless steel 6.Other environmental impacts.

 Haiyuan solution:

Stainless steel product quality problems:  our procurement channels are stable and bulk purchases. And we will We will sample inspection to ensure all the raw material quality is stable.