The working principle of the high-efficiency exhaust and filtration device is to achieve the capture, separation and purification of air pollutants through the synergistic effect of power-driven exhaust and multi-stage filtration and purification, while controlling the direction of air flow, and ultimately discharging clean air or qualified exhaust gas. Its core process can be broken down into the following key links:
I. Airflow Directional guidance
The device generates negative or positive pressure power through fans (centrifugal fans, axial flow fans, etc.) to form a directional air flow path, ensuring that pollutants are “targeted” collected.
Negative pressure guidance: In most scenarios (such as fume hoods and biosafety cabinets), the device creates a local negative pressure in the area where pollutants are generated (such as laboratory benches and production workstations), allowing the surrounding air and pollutants to naturally flow into the device and preventing them from spreading to the external environment.
Positive pressure discharge: The purified air or waste gas is pressurized by a fan and discharged to the outside or subsequent treatment system along a preset path (such as an exhaust pipe) to ensure stable airflow and no backflow.
Second, multi-stage filtration and purification
Depending on the type of pollutants (particulate matter, gas, microorganisms, etc.), the device is usually equipped with multi-stage filtration units to purify the air step by step:
Pre-treatment filtration (primary/intermediate filtration
Function: Remove large particles of impurities in the air (such as dust, hair, and fibers), protect subsequent high-precision filter materials, and extend their service life.
Common materials: metal mesh, non-woven fabric, glass fiber filter screen. The filtration efficiency is suitable for particles ≥5μm (primary) or ≥1μm (intermediate).
High-efficiency/ultra-high-efficiency particulate matter filtration
Function: Capturing fine particulate matter (such as dust, aerosols, and microbial spores), it is the core purification process.
Common materials: HEPA (High-efficiency air filter, with a filtration efficiency of ≥99.97% for particles ≥0.3μm), ULPA (ultra-high-efficiency air filter, with a filtration efficiency of ≥99.999% for particles ≥0.12μm), achieving purification through principles such as fiber interception, inertial collision, and diffusion adsorption.
Gas/Odor filtration (configured as needed)
Function: It removes harmful gases (such as VOCs, acidic gases, ammonia) or odors through chemical adsorption or catalytic decomposition.
Common materials: Activated carbon (for physical adsorption), impregnated activated carbon (such as loaded with potassium permanganate, for acidic/alkaline gases), catalysts (such as photocatalysts, for decomposing VOCs).
Iii. Airflow Balance and Safety Control
Air volume regulation: The exhaust air volume is controlled by the air valve or variable frequency fan to ensure the stability of the negative pressure/positive pressure inside the device (for example, in a biosafety cabinet, the negative pressure inside the cabinet needs to be maintained to prevent the leakage of contaminants).
Monitoring and Alarm: Some high-end devices are equipped with pressure sensors (to monitor the resistance of the filter and determine if replacement is needed) and airflow sensors (to monitor whether the airflow direction is abnormal). When abnormal conditions occur, audible and visual alarms are triggered to ensure operational safety.
Secondary protection: In high-risk scenarios (such as biosafety laboratories), redundant filter units (such as dual HEPA filters) may be added at the exhaust end to prevent pollutant leakage caused by the failure of a single filter.
Summary
The essence of the high-efficiency exhaust and filtration device is a systematic project of “directional collection → hierarchical purification → safe discharge” : by controlling the flow direction of pollutants through the power system, different filtration materials are used to specifically remove particulate matter, gases and other pollutants, ultimately achieving clean air circulation or standard exhaust gas discharge, and is widely applicable to scenarios with strict requirements for air cleanliness and safety.
I. Airflow Directional guidance
The device generates negative or positive pressure power through fans (centrifugal fans, axial flow fans, etc.) to form a directional air flow path, ensuring that pollutants are “targeted” collected.
Negative pressure guidance: In most scenarios (such as fume hoods and biosafety cabinets), the device creates a local negative pressure in the area where pollutants are generated (such as laboratory benches and production workstations), allowing the surrounding air and pollutants to naturally flow into the device and preventing them from spreading to the external environment.
Positive pressure discharge: The purified air or waste gas is pressurized by a fan and discharged to the outside or subsequent treatment system along a preset path (such as an exhaust pipe) to ensure stable airflow and no backflow.
Second, multi-stage filtration and purification
Depending on the type of pollutants (particulate matter, gas, microorganisms, etc.), the device is usually equipped with multi-stage filtration units to purify the air step by step:
Pre-treatment filtration (primary/intermediate filtration
Function: Remove large particles of impurities in the air (such as dust, hair, and fibers), protect subsequent high-precision filter materials, and extend their service life.
Common materials: metal mesh, non-woven fabric, glass fiber filter screen. The filtration efficiency is suitable for particles ≥5μm (primary) or ≥1μm (intermediate).
High-efficiency/ultra-high-efficiency particulate matter filtration
Function: Capturing fine particulate matter (such as dust, aerosols, and microbial spores), it is the core purification process.
Common materials: HEPA (High-efficiency air filter, with a filtration efficiency of ≥99.97% for particles ≥0.3μm), ULPA (ultra-high-efficiency air filter, with a filtration efficiency of ≥99.999% for particles ≥0.12μm), achieving purification through principles such as fiber interception, inertial collision, and diffusion adsorption.
Gas/Odor filtration (configured as needed)
Function: It removes harmful gases (such as VOCs, acidic gases, ammonia) or odors through chemical adsorption or catalytic decomposition.
Common materials: Activated carbon (for physical adsorption), impregnated activated carbon (such as loaded with potassium permanganate, for acidic/alkaline gases), catalysts (such as photocatalysts, for decomposing VOCs).
Iii. Airflow Balance and Safety Control
Air volume regulation: The exhaust air volume is controlled by the air valve or variable frequency fan to ensure the stability of the negative pressure/positive pressure inside the device (for example, in a biosafety cabinet, the negative pressure inside the cabinet needs to be maintained to prevent the leakage of contaminants).
Monitoring and Alarm: Some high-end devices are equipped with pressure sensors (to monitor the resistance of the filter and determine if replacement is needed) and airflow sensors (to monitor whether the airflow direction is abnormal). When abnormal conditions occur, audible and visual alarms are triggered to ensure operational safety.
Secondary protection: In high-risk scenarios (such as biosafety laboratories), redundant filter units (such as dual HEPA filters) may be added at the exhaust end to prevent pollutant leakage caused by the failure of a single filter.
Summary
The essence of the high-efficiency exhaust and filtration device is a systematic project of “directional collection → hierarchical purification → safe discharge” : by controlling the flow direction of pollutants through the power system, different filtration materials are used to specifically remove particulate matter, gases and other pollutants, ultimately achieving clean air circulation or standard exhaust gas discharge, and is widely applicable to scenarios with strict requirements for air cleanliness and safety.
