The method to test the quality of high-efficiency air filters is to lay the air filter flat on the ground or table, and sprinkle some water on the filter paper:

(1) If the filter paper seeps into the water within 5 minutes, it is an air filter made of cotton pulp paper (fake and inferior filter paper) that cannot be used. This type of air filter is mostly produced by a few people in the air compressor industry who are greedy for cheap prices.

(2) If the filter paper that seeps into the water within 2-5 hours is made of low-grade wood pulp paper, it can be used, but it will reduce the gas production efficiency of the air compressor (more electricity consumption, less gas production), resulting in more electricity consumption of the air compressor. Due to the relatively low price and suitability of air filters made of this filter paper, it is the mainstream air filter in the air compressor industry, and the vast majority of air compressor stores sell this type of air filter.

(3) If the filter paper takes 12-15 hours for water to seep in, it is considered a better filter paper (medium grade filter paper). Generally, domestic whole machine factories with better quality use air filters of this type of filter paper as factory consumables.

(4) If the filter paper does not seep in for 24 hours, it is definitely an excellent product (high-end filter paper). Usually, high-end machine factories choose this type of air filter paper as their original consumables.

Particle counting method

This method is commonly used in Europe, and the testing method for ultra-high efficiency filters in the United States is also quite similar, making it the mainstream testing method internationally. The dust source is polydisperse liquid droplets or solid dust with a determined particle size. Sometimes, filter manufacturers need to use atmospheric dust or other specific dust according to user specific requirements. If a nodule counter is used in the test, a single dispersed phase test dust source with known particle size must be used. The main measuring instruments are high flow laser particle counters or condensation nodule counters (CNC). Use a counter to scan and inspect the entire exhaust surface of the filter. The counter provides the number of dust particles at each point and can also compare the local efficiency of each point.

The experience of Europeans shows that for high-efficiency filters, the most easily penetrating dust particle size is 0.1µ M~0.25µ At a certain point between m, first determine the test conditions that are most likely to penetrate the dust particle size, and then continuously scan and measure the filter's effectiveness on the dust particle size. Europeans refer to this method as the MPPS method. The US standard only measures 0.1~0.2µ Particles in the m interval. The MPPS method is actually also a particle counting method, as the detection instruments used are particle counters or condensed nuclear particle counters.

The testing of high-efficiency air filters in China is mainly based on GB/T 13554-2008 "High Efficiency Air Filters", GB/T 14295-2008 "Air Filters", JB/T 6417-1992 "Air Filters for Air Conditioning", and GB/T 6165-2008 "Performance Test Methods for High Efficiency Air Filters - Filter Efficiency and Resistance". The testing methods include sodium flame method, oil mist method, and counting method, with the sodium flame method as the benchmark method. From the evolution process of international high-efficiency filter detection standards, it can be seen that the main testing methods for high-efficiency air filters include sodium flame method, oil mist method, DOP method, fluorescence method, and particle counting method.