laminar flow equipment || Pharmaceutical Engineering || Anurag Gupta

laminar flow equipment || Pharmaceutical Engineering || Anurag Gupta

1. Laminar Flow Equipment Anurag Gupta

2. Laminar air flow is an enclosed bench cabinet . It is designed to prevent contamination of biological samples or any particle sensitive materials . Laminar Flow Equipment Principle The air is passed through a HEPA filter which removes all airborne contamination to maintain sterile conditions.

3. Construction It is low cost and does not require more space. The cabinet is made up of stainless steel without gaps or joints thereby preventing the buildup of bacteria from collecting anywhere in the working zone. They are also known as clean benches because the air for the working environment is thoroughly cleaned by the precision filtration process. They consist of a filter pad, a fan, light with 100 lux and UV tube to disinfect the bacterial growth and a HEPA filter. The fan sucks the air through the filter pad to trap the dust particles. After that the pre-filtered air has to pass the HEPA filter where all the microorganisms are removed 99.97% of airborne particles 0.3 um in diameter. Finally, sterile air flows into the working area without risk of contamination. The air flows at a speed of 100 ft/min and sweep dust particles making entire room free of particulate matter. This helps to perform work under aseptic condition.

4. Air Flow Pattern Generally air flow pattern in the clean rooms are of 3 types.

5. Unidirectional air flow is an air flow pattern in which essentially the whole body of the air within a confined area moves with uniform velocity and in single direction with parallel air streams that means it is an airflow where a fluid flows in one direction with no interruptions from turbulence. It should have uniformed airflow at a speed of + 15% and the speed of the air is measured as it exits the HEPA / ULPA filter Unidirectional air flow

6. Non-unidirectional air flow is an air distribution where the supply air entering the clean zone mixes with the internal air by means of induction. The room air change rate per hour is calculated by the total airflow for the room is divided by the room volume and a capture hood is used to measure the volume of air exiting the HEPA / ULPA filter   Non-unidirectional Air Flow

7. Combined air flow is a combination of both Unidirectional and Non-Unidirectional airflows Combined Air Flow

8. Types Mainly two types likely Horizontal Laminar Air Flow & Vertical Laminar Air Flow

9. In this cabinet, the direction of air flow comes from above but then changes direction and is processed across the work in a horizontal direction . The constant flow of filtered air provides material and product protection Horizontal Laminar Flow Cabinets

10. It is also same as well as horizontal Laminar Flow Cabinets with the laminar air directed vertically downwards onto the working area. The air can leave the working area via holes in the base. Vertical flow cabinets provides greater operator protection Vertical Laminar Flow Cabinets

11. Uses 1) It has various applications, especially where an individual clean air environment is 2) Required for smaller items, e.g., particle sensitive electronic devices. 3) It is used for special operations in laboratories. 4) It can be tailor made to the specific requirements of laboratories and are also used for general lab work, especially in medical, pharmaceutical, electronic, and industrial sectors.  

12. 1. The persons working in the area do not feel the movement of the air 2. The body of filters is made up of stainless steel which is not favorable for bacterial growth. 3. The HEPA filter can reduce the contamination . 4. The sterile area is spacious. 5. Since the sterile area does not become hot, the plant material can stay for a longer duration . 6. Bigger flasks having wide lids can be used. Advantages

13. Limitation The airflow velocity can be overcome easily without any strict work practices and aseptic technique , thus an area of turbulence is created which can introduce room contaminants particles and microorganisms) into the critical work area. A laminar air flow hood should remain on for 24 hours. If it is turned off, it should be left on for at least 30 minutes for its disinfection before use.