What conditions should be met when designing a closed hood

Papermaking industry is a high input industry. Large paper machines, coaters and finishing equipment are basically imported, and almost all of them are imported from the whole production line. The country spends a lot of foreign exchange on purchasing papermaking equipment every year. In order to change this situation, the state has issued some policies to encourage domestic enterprises to tackle the technical problems of paper-making equipment and try to improve the localization rate of large-scale paper-making equipment.

The value of the closed hood of the drying section in the ventilation system of the paper machine is relatively high. The closed hood is a very important equipment in the paper machine. The design of the closed hood must meet the following functions:

1. Provide a closed high-temperature environment to facilitate the drying of paper sheets, reduce the exhaust air volume, and improve the effect of exhaust heat recovery of the hood. The most popular design in the world is 80-85c dry bulb temperature and 58-62'c dew point temperature in the hood.

2. The closed hood must provide convenience for the monitoring, operation and maintenance of the paper machine operation, and must be able to easily lead paper and change rolls.

3. The high temperature and humidity in the closed hood is particularly easy to cause condensation. The design of the hood must completely eliminate the condensation and dripping of the roof of the hood.

4. Try to keep the air in the hood from emitting to the workshop.

5. The closed hood shall be able to adjust the longitudinal exhaust air volume of the paper machine to ensure the exhaust air volume required for each dry part of the paper web.

6. Lighting, fire fighting and other facilities shall be fully considered for the closed hood to meet the needs of all aspects.

7. The enclosed hood occupies a large area in the paper workshop, so the appearance of the hood must be beautiful and durable.

Over the years, closed hood manufacturers have been doing fruitful research in the field of paper ventilation, and have achieved success in the research, production and use of major paper ventilation equipment. They mainly include the closed hood of the drying section, the blow boxes with various functions in the hood, the heat recovery device of the hood exhaust, the exhaust and supporting equipment of the wet end of the paper machine, the conveying equipment of the paper side, the unit ventilation unit of the workshop, etc.