A Laminar Flow Hood is large equipment that regulates air flow, especially of contaminated air. They are used in research centers and hospitals and they protect researchers or users from a harmful or toxic environment. Almost all biological laboratories will have one of these hoods as they handle compounds that are sensitive and need an environment that is devoid of contaminants and toxic particles. The Laminar Flow Hoods are designed in a way that the cleanest area is near the face of the filter through which air flows in.
There are two types of Laminar Hoods in the market – VerticalLaminar Flow Hoods and the Horizontal Laminar Flow Hoods. The selection of these units is based on clearance requirements, the design of the work surface, operator safety and process location.
How to choose the correct equipment?
Vertical Laminar Hoods
If the application needs space for larger equipment on the work surface, then the vertical hood is best. It does not create as much turbulence when air hits items in its path. This is quite opposite to a horizontal hood.
If you are going to use fine powders or will be soldering something, then vertical hoods must be chosen. Vapours from soldering can be toxic because of acidic fumes and metal oxides from flux. In such a case a vertical hood is better than a horizontal one as it doesn’t blow air directly onto the user’s face.
A Vertical Laminar Hoods provides a larger and taller workspace as the filters are positioned on top. The filters don’t eat into space for working and a greater height is available.
The air is pulled from the top and a fan pushes it through the filters into the enclosure. The filter is on the top and may require a ladder for access. The plenum at the back will facilitate air recirculation, thereby reducing the quantity of contaminated air from passing through the filter again. The exhausted and filtered air can exit through the enclosure.
Any particles that settle at the bottom of the device get swept out with the airflow, but the same cannot be said for a horizontal hood, as the air pressure wouldn’t be same.
Horizontal Laminar Hoods
This type of hood ensures lesser turbulence on the work surface area. The horizontal hood may not hit any obstructing item until usually exiting the hood.
Small equipment or items must be used in the horizontal hood as larger equipment in this, tend to cause more turbulence.
The chances of contamination are lesser as items like gloves are positioned further downstream, thus allowing purified air to decontaminate items in its path before hitting the gloves.
The ambient air is pulled in from the back part of the unit, while a module pushes it through the filters. There are air slots on the side in order to minimize turbulence over the work surface. The contaminants can get blown onto the user’s face. The air then exits the enclosure back into the room.