Compared with the traditional open gas hood, the price of the closed gas hood is higher, because the closed gas hood needs to consider more safety and environmental protection requirements in the design and production, and needs to invest more funds.

In order to ensure good sealing and stable operation, it is necessary to check and maintain sealing materials, ventilation pipes, valves and other components. For example, sealing materials may be aging and damaged, which will increase the cost of human and material resources for maintenance.

Because the system is relatively complex, once the ventilation, temperature regulation, gas purification and other parts of the fault, diagnosis and repair is more difficult, may lead to long-term interruption of the production process.