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Aseptic Products

Aseptic Isolators are available with two possible airflow designs – turbulent airflow and zonal unidirectional airflow.

Turbulent Airflow

Turbulent airflow allows filtered air to be mixed with airborne contaminants, which dilute the contaminants and dispenses them through an air filtration system. This method of turbulence and dilution is dependent upon the volume of air that is cycled into the environment and larger volumes of air require more time to process. During this process, particles may be suspended in the air, some of which may become stagnant and harbour contaminated particles.

Zonal Undirectional Airflow

Zonal unidirectional airflow allows a separated area to be continuously showered with high-speed, filtered air. This sweeps contaminants away from the product, into the turbulent area and out of the environment through an air exhaust system.

Unidirectional Airflow

The unidirectional airflow design is the more efficient design with respect to eliminating contamination. However, both designs have practical applications in the overall process.

Unidirectional/Zonal designs are best suited for applications such as compounding.  The continuous showering of filtered air sweeps away contamination almost immediately. Unidirectional designs offer flow control, which has traditionally been recommended at 0.45m/sec (90 fpm). The desired airflow velocity however, is dependent upon the desired results to rid the environment of contaminates.

Turbulent airflow designs are best suited for aseptic environments, such as those environments that surround a compounding area.  Turbulent airflow designs offer dilution control, where filtered air is used to dilute and eliminate contamination over time.

Isolator Pressurisation

The Isolator can be configured for either positive or negative pressure operation.

In either positive or negative pressure configurations the airflow in the isolator is always in the same direction. To achieve positive pressure the air supply duct pushes air into the chamber faster than it is exhausted. To achieve negative pressure the exhaust duct vents air out of the chamber faster than it is taken in. 

The decision to operate the Isolator under negative or positive pressure must be determined based on your intended product application, risk assessment and current regulations.

  • Positive Pressure should be used when product protection has been determined to be the greatest concern because it reduces the chance of introducing contaminants.
  • Negative pressure should be used when personnel protection has been determined to be the greatest concern because it keeps the internal environment of the isolator away from the operator.