Laminar flow cabinet

Laminar Flow Cabinet

A laminar flow cabinet or laminar flow closet or tissue culture hood is a carefully enclosed bench designed to prevent contamination of semiconductor wafers, biological samples, or any particle sensitive materials. Air is drawn through a HEPA filter and blown in a very smooth, laminar flow towards the user. The principle behind the laminar flow cabinet is to provide a workspace that has a unidirectional air flow, meaning the air flows in a single direction at a uniform speed. This helps in preventing cross-contamination among the samples placed in the cabinet.

Types of Laminar Flow Cabinets

Laminar flow cabinets can be categorized into two main types based on the direction of air flow: horizontal or vertical.

Horizontal Laminar Flow Cabinets

In a horizontal laminar flow cabinet, the air is filtered and blown out across the work surface in a horizontal direction. This type is commonly used for operations where the product is more likely to be contaminated by the operator rather than the air, such as in microelectronics assembly.

Vertical Laminar Flow Cabinets

Vertical laminar flow cabinets, on the other hand, direct the filtered air downward onto the work surface. These are preferred in situations where any interference from the operator must be minimized, such as in handling sterile pharmaceuticals or performing tissue culture work.

Construction and Operation

Laminar flow cabinets are constructed from materials that are easy to clean and disinfect, typically stainless steel or coated steel. The cabinets are equipped with HEPA filters that remove 99.99% of particles greater than 0.3 micrometers from the air. The filtered air is then passed over the work area in a laminar flow, protecting the samples from contamination.

Operators of laminar flow cabinets must follow strict procedural protocols to maintain the sterility and integrity of the controlled environment. This includes wearing appropriate protective clothing, carefully placing items within the cabinet to avoid disrupting the airflow, and regular cleaning and maintenance of the cabinet itself.

Applications

Laminar flow cabinets are used in a variety of settings, including research laboratories, hospitals, and manufacturing facilities. Their applications include:

• Preparation of sterile pharmaceuticals
• Assembly of electronic components
• Cultivation of plant and animal cells
• Preparation of media and cultures in microbiology

Safety and Maintenance

While laminar flow cabinets are designed to protect samples from contamination, they do not provide protection to the operator from hazardous substances used within the cabinet. Therefore, it is crucial to use proper personal protective equipment (PPE) and follow safety protocols.

Regular maintenance of a laminar flow cabinet is essential to ensure its proper functioning. This includes periodic testing and replacement of HEPA filters, cleaning and disinfecting the work surface, and ensuring that the airflow remains uninterrupted.

See Also

• Cleanroom
• Biosafety cabinet
• HEPA filter
• Microbiology