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Hepa filter is not up to standard

2018-12-12

What are the factors that cause the hepa filter detection to fail?

Since the hepa filter is installed in a place where the cleanliness requirements are strict, the filter will pass the test one by one before leaving the factory, and the hepa filter can be used in two types. One is the factory inspection and the other is the on-site inspection. During these two tests, the reasons for the filter detection not reaching the target may be as follows:

1. The surface of the filter material is broken or slightly damaged. It is easy for the naked eye to observe the damage of the filter material, and it is easier to repair a small amount of damage. This repair is best carried out at the filter manufacturer. Some minor damage is not easy to observe with the naked eye, and can only be detected after testing by the test bench. If it is only damaged and not serious in some places, it may be repaired into a qualified product, but the quality of the repair should meet the standard requirements.

Second, the sealing defect, the filter material and the outer frame of the filter are leaking. In production inspection, most of the inefficiencies are caused by such air leakage. Most of this can be fixed, but the appearance after repair cannot be obviously flawed. Many hepa filter have a sealing strip on the border. Sometimes the interface is not handled well, which will cause air leakage. Some manufacturers use on-site foamed polyurethane sealing strips, without seams, there is no air leakage problem. If a strip with a joint is used, the joint is preferably in the form of a labyrinth.

Third, the efficiency of the filter material. If the efficiency of the filter itself is not sufficient, a qualified filter cannot be manufactured. Everyone knows this, but there are some products on the market that are marked to be efficient, and they do not achieve efficient filter media.

Fourth, the material is dusty. Traditionally, there is a separator high-efficiency filter. If it is a paper separator, and the material control is not strict, the paper separator has the risk of dusting. The filter material production environment is poor, the filter material itself has a large amount of dust that may fall off, and the filter made may also generate dust. It is worth noting that some inspection methods cannot detect such dusting.

Fifth, the detection of its own problems. When the factory detects, if the scanning detection method is used, there may be eddy currents on the air outlet surface of the filter, and the surrounding dust enters the scanning area along with the eddy current. If eddy currents exist, dust must be exceeded when scanning. At this time, you cannot judge whether the dust is from the filter leak or eddy current. The inexperienced operator may judge the filter as waste. There is also a case where after installing the filter, people use the downstream dust concentration to judge whether the filter is qualified. At this time, even if the filter efficiency is qualified, it may be misjudged as unqualified due to the high downstream concentration.