Are Vacuum Cleaners Suitable for Laminar Flow Hoods as blowers...?
I have used Euroclean Star model vacuum cleaner to be used as blower in the flow hood. Let us check out the facts for its suitability for quality and effectiveness for being used in a flow hood. Filtration:
The model I used consists of unique five stage filtration process and the air coming out after filtration is pure and fresh...
The first stage involves the incoming air to pass through a special particle, anti-microbial, biocide treated paper filter which has been treated for protection against bacteria, fungus and yeast. This paper bag is replaceable and can be used for up to five times. However, for better results, we can use fresh bag whenever we use the laminar flow hood. This air then passes through a cloth bag, which filters out any particle which escapes through the paper bag. This bag can be removed, cleaned and then placed again in position. The next three stages involve the air to pass through specially designed built-in electric filters with carbon which blows out completely pure fresh air.
I have removed the outer-most filter and provided a cheaper version of High Efficiency Particulate Air (HEPA) filter between the air chamber and the work area. I have also added a pre-filter to remove any heavier particles before the air is sucked into the vacuum cleaner. Work area provided by the blower
Laminar flow hoods are designed to provide an air-flow of about 0.5 meters per second in the working area. The blower efficiency of the model I have used is 20 liters per second, that is 0.020 cubic meters per second including all filters. I have removed the outer most filter from the outlet for connecting the outlet pipe, and used the HEPA filter instead.
With 0.020 cubic meter of air per second, let us see how much work area it can cover
Air flow provided by the blower = width of HEPA filter x height of HEPA filter x air speed required
Work area (width x height) = air flow / air speed
= 0.020 / 0.50
= 0.04 square meter
Now, if we provide HEPA filter area of 0.27 meter width x 0.15 meter height, the available work area will be 0.04 square meters, which is sufficient for the effective functioning of the flow hood. I have provided the filter dimensions of 0.29 meters width by 0.15 meters height, considering the size of HEPA filter I could lay my hands on. Advantages of using a Vacuum Cleaner as blower
There are some advantages in using vacuum cleaners, which may not be provided in a Laminar Flow Hood
- The air input level can be adjusted using a slider provided with the vacuum cleaner as per our requirement. Not all blowers in the laminar flow hoods are provided with adjustable air flow.
- There is also an option to heat the input air, which will be helpful in sterilizing the air chamber and back side of the HEPA filter which can not be normally accessed.
- What is more, you can vacuum clean the air-tight Air chamber by reversing the airflow by the vacuum cleaner unit.
- The vacuum cleaner unit can be separated from the Laminar Flow Hood, which is not at all possible with a normal unit.
The only disadvantage of using a vacuum cleaner is its limited airflow which limits the size of the sterile work area.
I think a suitable vacuum cleaner will serve the purpose of blower in a small Laminar Flow Hood for hobbyists, thus reducing the cost as well as the weight of the flow hood considerably.