A brief introduction to the open ventilation hood of paper machine drying device

Paper machine, for paper-making equipment, belongs to the category of equipment accessories. Paper machine is a kind of machine which can make paper from pulp which meets the requirements of paper making after beating and mixing. A very heavy system of paper machine is the ventilation and drying system, in which the hood is an important part. Usually, the ventilation hood is an important part of the drying device. Because the organization design and economic effect of ventilation and heat recovery device depend on the form of ventilation hood and its thermal performance. There are two main forms of multi cylinder paper machine ventilation hood, open type and fully closed type; for example, the closed hood produced by Fengxin technology is one of them.

Open type ventilation hood, which is mainly suitable for low medium speed and narrow width paper machines, still occupies a high proportion in China's paper machines. The lower edge of the cover is usually about 2m away from the floor of the paper machine. Most of the air discharged from the hood comes from the workshop. Some have a hot air blanket blowing system. The system uses the heat from the hot and humid exhaust gas discharged to heat the fresh air introduced from the outside of the workshop through a heat exchanger. The heated fresh air is blown to the drying cylinder and the ceiling of the paper-making workshop. On the one hand, the dry blanket is dried and the temperature is increased. On the other hand, the air in the workshop is supplemented to prevent the condensation of the ceiling The dry hot air enters into the drying section to take away more water vapor; it is also used to ventilate the bag area after further heating. Generally, hot air is added to the drying section of the workshop. The temperature of the open cover is 48 ℃ and the ventilation temperature of the bag area is 90-130 ℃.

The structure of closed hood of paper-making machinery is composed of air cover wall, top layer of hood, air duct and exhaust outlet. The wall and top layer of air hood are composed of aluminum alloy plate and steel frame with insulation layer in the middle. There are several air ducts and exhaust outlets with rectangular cross-section above the air hood on the drive side, and movable partitions are set on both sides of the air duct to adjust the exhaust volume of each section of the drying section.