What is the working principle of the high-efficiency exhaust unit?

The working principle of the high-efficiency exhaust unit mainly revolves around two core aspects: air purification and filtration, and safety protection and control. Through multi-layer processing and intelligent regulation, it achieves efficient purification and safe discharge of air containing pollutants. Specifically, it can be divided into the following key links:
1. Air introduction and initial filtration
Air containing pollutants (such as dust, pathogenic microorganisms, chemical volatiles, etc.) is introduced into the air inlet of the high-efficiency exhaust unit through connecting pipes from the pollution source area (such as laboratories, isolation wards, etc.).
First, it passes through the primary filter (usually made of non-woven fabric or metal mesh material), which utilizes the physical interception effect to remove larger diameter particles in the air (such as dust and fibers with a particle size of ≥5μm), preventing large particles from clogging the subsequent high-efficiency filters and extending their service life.
2. High-efficiency purification and filtration (core link
The air that has undergone primary filtration enters the core purification stage and undergoes advanced treatment through high-efficiency filters (HEPA) or ultra-high-efficiency filters (ULPA).
HEPA filters are made of special glass fiber or synthetic fiber materials. Through a combined mechanism of "interception, inertial collision, and diffusion adsorption", their filtration efficiency for particles with a diameter of ≥0.3μm can reach over 99.97%. ULPA can filter particles with a diameter of ≥0.12μm, with an efficiency of over 99.999%.
This step can effectively intercept tiny pollutants in the air (such as bacteria, viruses, radioactive particles, chemical aerosols, etc.), ensuring that the air discharged from the filter meets the safety emission standards.
3. Pressure and flow regulation
The unit is equipped with an internal fan or is linked to an external ventilation system. Through stable air pressure and air volume control, it ensures unidirectional air flow (from the air inlet to the air outlet), preventing the backflow of pollutants.
Meanwhile, the differential pressure detection instrument monitors the pressure difference on both sides of the primary filter and the high-efficiency filter in real time. When the pressure difference of the filter exceeds the set threshold due to blockage, the system will issue an alarm, indicating that the filter needs to be replaced to ensure the stability of the filtration efficiency.
4. Safety isolation and leakage prevention
Biosafety airtight valve: Install airtight valves at the air inlet and outlet, and keep them open during normal operation to ensure smooth airflow. When the system shuts down, malfunctions, or undergoes disinfection, the valve will quickly close, creating a physical isolation to prevent residual contaminants in the pipeline from flowing back into the room.
The box body adopts an airtight design (such as rounded corners, sealing strips, etc.) to ensure that the internal gas will not leak through the gaps. Especially when dealing with highly hazardous pollutants, it can minimize the risk of environmental exposure to the greatest extent.
5. Disinfection and maintenance assurance
When it is necessary to disinfect the interior of the unit (especially the residual contaminants on the surface of the filter), the system initiates the disinfection process:
Close the airtight valves of the air inlet and outlet, introduce gaseous disinfectants (such as hydrogen peroxide, formaldehyde, etc.) through the disinfection interface, and cooperate with the circulation device to ensure that the disinfectants are fully diffused in the box, penetrate the filter fibers, and kill the remaining pathogenic microorganisms.
After disinfection is completed, the residual disinfectant is discharged through the pressure relief port to ensure that the air discharged during the next operation is free from secondary pollution.
Summary
The core logic of the high-efficiency exhaust unit is "filtration and purification first, then safe discharge, supplemented by full-process monitoring and emergency protection". Through the coordinated effect of multi-layer filtration, pressure regulation, airtight isolation, and active disinfection, it can not only efficiently remove pollutants in the air but also strictly prevent leakage. It is suitable for scenarios with extremely high requirements for air safety (such as biological laboratories, medical isolation areas, hazardous materials workshops, etc.).