Explosion-proof FFU Filter Replacement Judgment Method (Practical Version, General for Explosion-proof Clean Rooms)
Core Principle: Prioritize checking the pressure difference, followed by time, air flow, and environment. It is strictly prohibited to operate with the filter blocked in explosion-proof environments.
1. The Most Standard Method: Pressure Difference Method (Most Accurate, Must Be Used)
FFU comes with a pressure difference gauge / external pressure difference meter. Measure the pressure difference before and after the filter.
Initial resistance of new high-efficiency filter: 120–180 Pa
When the pressure difference reaches 300–350 Pa → Must be replaced
In lithium battery, chemical explosion-proof workshops, it is recommended to replace when the pressure difference reaches 280 Pa to prevent overload and overheating of the motor and the generation of ignition sources (Key points of explosion-proof)
In explosion-proof areas, it is strictly prohibited to have severe blockage of the filter, increased motor load, and excessive temperature rise, as there is an explosion risk.
2. Time Period Method (Reference when there is no pressure difference gauge)
General explosion-proof clean area: 6 months
Lithium battery, electrolyte, solvent, dust environment: 3 months
Continuous 24-hour operation: 2–3 months
3. Intuitive Visual + Operating State Judgment
The air outlet becomes smaller, the wind speed significantly decreases, and the air volume at the same position weakens
The fan noise becomes louder, the vibration becomes greater, and the motor gets hot (Key points to be vigilant in explosion-proof environments)
The number of particles in the clean room increases, and the cleanliness does not meet the standard
The filter surface turns black, there is a lot of accumulated dust, there is oil contamination, electrolyte crystallization, and dust clumping
4. Special Attention Points in Explosion-proof Environments
After the filter adsorbs electrolyte, alcohol, and flammable dust, it is already a combustible substance. Even if the pressure difference has not reached the limit, it must be replaced in advance.
When replacing, power must be disconnected. It is strictly prohibited to open the cover while powered on. After replacement, lock the explosion-proof cover plate and sealing parts.
The old filter material removed belongs to hazardous waste and cannot be discarded casually. It should be treated as flammable and explosive waste.
