The clean bench is one of the main laboratories in the research and application fields of life scien

The clean bench is one of the main laboratories in the research and application fields of life sciences, biochemistry, medicine and health, agricultural scientific research, food production, environmental monitoring, etc. It can provide partial clean air purification equipment. Its working principle is that indoor air enters the static pressure box through a pre-filter, and then passes through a high-efficiency air filter (hereinafter referred to as HEPA filter) to remove various dust particles or aerosols, and finally forms a highly clean unit in the operating area. A positive pressure airflow environment that directs airflow and avoids the introduction of external airflow.

Clean bench


A neglected and worrying hidden danger of biotechnology. With the development of modern biotechnology, the issue of biosafety has aroused the close attention of many scientific and technological workers in the biological field. Super workbench is indispensable for carrying out biotechnology research. It is one of the most widely used basic equipment, but its biological safety and effectiveness are seriously challenged by the effectiveness of its key component HEPA filter. At present, due to the lack of effective monitoring of the service life of the key components of the HEPA filter membrane in the product design process, the super workbenches used in large quantities in the country make it difficult for the experimenters to intuitively make accurate judgments on the effectiveness of the HEPA filter membrane, and even cause Serious consequences such as inaccurate experimental data, contaminated experimental samples, or repeated failures of experimental projects. At present, in a large number of domestic biological laboratories, universities, scientific research institutes, and biopharmaceutical companies and other research application fields, it is more common to have the problem of overdue service and invalid use of HEPA filter membranes to varying degrees. The safety and effectiveness of the workbench are quite prominent, but on the other hand, this worrying issue of the effectiveness of biotechnology has become a hidden danger and has been ignored by many people.
This is a design flaw that has not been fully recognized. At present, the electrical control of the super workbenches seen in the domestic market is basically similar to the control principle of an electric fan, that is, a fan, a multi-tap transformer, and Plus a control system composed of a multi-speed speed switch. When the super workbench is running, there is only the prompt of the wind speed gear on the control panel, and the super workbench does not have any prompts concerning the operating status of the HEPA filter. Although some manufacturers are aware of the importance of prompting the experimenter about the operating status of the HEPA filter, they have taken certain measures in product design. For example, install a pressure probe in the static pressure box of the super workbench to measure the pressure change in the static pressure box, and then use the red and green range of the pointer pressure gauge or use the digital pressure gauge on the display Shows the pressure change in the static pressure box, the initial pressure is equivalent to the initial resistance of the HEPA filter, and the increase in pressure is equivalent to the increase in the resistance of the HEPA filter. And use the designed pressure limit value as the analysis basis to judge the remaining service life of the HEPA filter membrane and issue relevant warnings to the experimenters.
But experiments have shown that this method is not authentic. Because the wind speed, air volume, pressure, and resistance changes in the super workbench are an interaction and mutual influence system, for example, changing the wind speed gear to change the air volume, the wind speed will also change, and the pressure will change accordingly. Therefore, the pressure change displayed by the equipment does not actually reflect the change in the resistance of the HEPA filter. Furthermore, the judgments made about the operating state of the HEPA filter are also inaccurate and have no reference value. In order to make up for the equipment's inability to judge the operating status of the HEPA filter, many domestic experimenters have taken frequent replacement of the HEPA filter to improve the effectiveness of the purification function of the Super Workbench. However, this costly and laborious operation is simply difficult to maintain, and it is also difficult to know when to replace the HEPA filter. Therefore, the equipment is still being used when the HEPA filter has failed but the experimenters cannot detect it. This is the real situation of the current clean bench in my country's biological laboratories.