What are the main structures of the box of the biosafety cabinet?

Biological safety cabinet is a box type negative pressure safety device for air purification that can prevent the aerosol escape of some dangerous or unknown biological particles during experimental operation. It is widely used in scientific research, teaching, clinical testing and production in the fields of microbiology, biomedicine, genetic engineering, biological products, etc. It is the most basic safety protection equipment in the first level protective barrier of laboratory biological safety.
The working principle of the biosafety cabinet is mainly to draw the air in the cabinet outward to keep the cabinet in a negative pressure state, and protect the staff through vertical airflow; The outside air is filtered by the high efficiency air filter and then enters the safety cabinet to avoid contamination of the processed sample; The air in the cabinet shall also be filtered by HEPA filter and then discharged to the atmosphere to protect the environment.
The biosafety cabinet is generally composed of a box and a bracket. The box mainly includes the following structures:
① Air filtration system
The air filtering system is the most important system to ensure the performance of the equipment, which is composed of the driving fan, air duct, circulating air filter and exhaust air filter. Its main function is to continuously make clean air enter the working room, so that the velocity of the downdraft (vertical airflow) in the working area is not less than 0.3m/s, and ensure that the cleanliness in the working area reaches Class 100. At the same time, the external exhaust flow is purified to prevent environmental pollution.
The core component of the system is HEPA filter, which uses special fireproof materials as the frame. The frame is divided into grid shape by corrugated aluminum sheets, and filled with emulsified glass fiber sub particles, with high filtering efficiency. The pre filter cover or pre filter at the air inlet allows the air to enter the HEPA filter after pre filtering and purification, which can extend the service life of the HEPA filter.
② External exhaust box system
The external exhaust box system is composed of external exhaust box shell, fan and exhaust duct. The external exhaust fan provides the power for exhaust, draws out the unclean air in the working room, and is purified by the external exhaust filter to protect the samples and experimental articles in the cabinet. Because of the external exhaust effect, the working room is under negative pressure, preventing the air in the working area from escaping, which is intended to protect the operator.
③ Sliding front window drive system
The driving system of sliding front window is composed of front glass door, door motor, traction mechanism, transmission shaft and limit switch, which is mainly used to drive or pull each door shaft, so that the front glass door is in normal position during the operation of the equipment.
④ The lighting light source and ultraviolet light source are located inside the glass door to ensure a certain brightness in the studio and to disinfect the worktop and air in the studio.
⑤ The control panel is equipped with power supply, UV lamp, lighting lamp, fan switch, front glass door movement control and other devices, which are mainly used to set and display system status.