What is laminar flow hood?
Laminar flow hood is special equipment or workstation for working with biological objects in sterile zone. Such machine is used for microbiological and molecular-biological researches and also for works with dangerous and infected objects in microbiology lab. Many medical establishments, scientific stations, laboratories, corporations use it for realization of verifications, experiments and analyses of microbiological materials. Companies that work with pharmacy, electronics, optics, cell culture or tissue culture of animal or vegetable origin need laminar flow chamber too, because safety and sterile workbench is their main working principle.
If a company wants to buy laminar flow cabinet, there are some requirements for this choice. First of all this is the reliability, quality and good work of the system. It must be mechanical and electric filtration of laminar flow for sterilization and isolation of the checked materials and objects. The size of laminar flow cabinets could be different: from 1,2 to 1,8 meters for comfortable work with materials. It depends on the prospected objects and the place where the laminar camera will be set.
It is needed to take into account that there are 3 classifications of the protection degree. There are kinds that are not intended for work with dangerous materials and infected objects, because they do not provide protection for operator. Other classes protect operator from an infection during realization of analysis of the infected material, because they provide the cleaning of environment and working zone. The degrees of protection can differ from world standards and classification; it depends on a country and company-manufacturer. Stuff and operators who will work with laminar cameras must have necessary diplomas, certificates and permissions.
How laminar flow cabinet works?
It is a transparent closet with sterile desktop, where there is UV light, usual lights and filtration of laminar air flow. Incoming air goes evenly (without a whirlwind) in filter and provides clean air and isolation of the investigated object from harmful and dangerous microorganisms.
It is needed to know its class of biological protection to understand how to use laminar camera:
- Chambers of class I have simple work of HEPA filter. Air gets in laminar camera through an open frontal window where the object is and operator works. The incoming air is directed by the flow and sop in a filter that is located above. Process of collecting the air begins and gives the cleared air outside. The chambers of such class are not absolutely safe for operator, because does not protect him fully during procedure of researches. Many laboratories and centers use such models for technical or medical tests and works, but not for protecting from biohazard, because these laminar closets are out-of-date.
- Chambers of class II are identical to previous ones, but the difference is in the collection of incoming air. It gets to the filter not through the frontal window, but through the special grate. It is located next to operator, therefore protects him from any kind of dangerous biological influence. There is the second suction element that is located on the overhead panel of laminar chamber. Thus there is vertical air flow, so the air goes from top to bottom, enters filter and goes out clean. Efficiency is due to recirculation of air: about 30 % of all clean air goes out and other 70 % goes back to the camera and create a stream for future cleaning.
- Chambers of class III provide the highest level of protection. Different kinds of researches with such camera take place through an airtight chamber and gloves, which are connected by sealed ports. The air is cleaned inside through the filter; it can go out of the chamber in a clean form or get outside the building through ventilation. There is a reduced pressure gauge to ensure safe work with chemicals and biological objects inside the camera. Due to this, the operator can work even with deadly dangerous samples and viruses. Such cameras require attentive inspection and regular replacement filter.
Horizontal vs vertical
There are some certain differences in the process of air filtration and cleaning in horizontal and vertical cameras, but they are united by common advantages. Both types of chambers are equipped with high-quality filters, which purify incoming air from harmful substances. Most often, laboratories and research companies purchase vertical flow cameras, because it protects the operator well during its work. If a high level of protection is required from deadly viruses, radiation materials and hazardous objects, the laboratory chooses other types of cameras, regardless of the degree and type of air cleaning.
Horizontal laminar flow unit
Air comes through a filter and then enters the isolator – a chamber with pressure and fan. After this process air enters the main cleaning filter and returns to the benchtop zone. The pressure in the chamber is higher; therefore it prevents dust and harmful substances from entering the operator and the outer part of the laminar kit. These types of cameras need annual maintenance to evaluate the operation of the filter and replace it if necessary.
Vertical laminar flow hoods
This means that the laminar closet has a vertical airflow, which provides reliable protection for the object under investigation and operator during the working process. The air goes into the camera through the front window where the operator works and conducts the investigations and then the fume rises vertically to the filter and becomes clean there. Harmful air can enter the filter through small grids, which are located in the module opposite the front window. It depends on the type of vertical airflow hood.