Negative Pressure Isolators: Principle, Application, and Maintenance

Core Principle

The internal pressure of the isolator is lower than the external pressure, creating an inward-flowing air current. This design not only prevents internal hazardous materials (such as cytotoxins, API raw materials, volatile substances, etc.) from leaking out to contaminate the environment or harm operators during production, but also reduces the entry of external impurities into the isolator to avoid material contamination, thereby balancing operational safety and material safety.

Focusing on the "Isolation and Protection" Design, Supported by Three Key Links:

1. Reliable sealing and pressure difference control: A sealed box structure is adopted (with key sealing of gaps such as door seams and interfaces), combined with a pressure difference sensor to monitor air pressure status in real time. It can ensure stable negative pressure, and even when the operation door or feeding port is opened, the air speed at the gap can be maintained at no less than 0.5m/s to prevent leakage.    

2. Directional airflow and basic purification: The interior adopts a unidirectional airflow design to quickly remove internal dust or volatile gases, preventing materials from accumulating or diffusing in the cabinet. The air intake end is equipped with primary/medium efficiency filters to filter large particle impurities and meet basic protection requirements.      

3. Targeted filtration and emission system: The air exhaust end is equipped with a PUSH-PUSH high-efficiency filter, which intercepts over 99.995% of 0.3-micron particles (such as pharmaceutical dust and solid impurities). When handling volatile organic compounds (VOCs) or odorous materials, an additional activated carbon adsorption module can be installed, and the filtered air is discharged up to standard to avoid polluting the surrounding environment.

Application

Negative pressure isolators are widely used in the pharmaceutical industry, such as crushing/mixing of non-sterile active pharmaceutical ingredients, handling of low-toxicity excipients, testing of hazardous samples in laboratories, and packaging of low-risk chemicals in the chemical industry. They are particularly suitable for applications where "sterility is not required, but personnel contact or environmental diffusion needs to be avoided" and offer higher cost-effectiveness.

Three Core Points for Maintenance

1. Regularly inspect the cavity sealing (glove leak detection and leakage testing) to prevent protection failure caused by gap leakage.    

2. Replace filters according to usage frequency (regularly check HEPA filters for blockages by monitoring pressure differences at both ends of the filter and conducting integrity tests, etc.).

3. Clean the interior promptly after operation (by rinsing and wiping) to prevent cross-contamination or equipment corrosion caused by residual materials.

In summary, the core of non-sterile negative pressure isolators lies in "achieving precise protection at low cost": they focus on isolating hazardous materials through negative pressure and filtering and discharging pollutants. They not only meet basic safety and material protection needs but also control equipment costs and maintenance difficulty, making them practical equipment that balances safety and efficiency.