The paddle dryer has a compact structure and a small footprint of the device. It can be seen from the structure of the equipment that the heat required for drying is mainly provided by the walls of the hollow blades arranged on the hollow shaft, while the heat transfer from the walls of the jacket only accounts for a small part. Therefore, the heat transfer surface per unit volume of the equipment is large, which can save the floor space of the equipment and reduce the investment in infrastructure. High heat utilization rate. The sludge dryer is heated by conduction heating, and all heat transfer surfaces are covered with materials, which reduces heat loss; no hot air takes away heat, and the heat utilization rate can reach more than 90%. The heat transfer is uniform and the heat transfer effect is improved.
The hollow blade dryer, also known as the blade dryer, is mainly composed of a W-shaped shell with a jacket, two hollow blade shafts and a transmission device. Hollow blades are arranged on the shaft, and the shaft end is equipped with a rotary joint for the introduction of heat medium. The heat required to dry the moisture is conducted to the material by the inner wall of the jacketed W-shaped groove and the wall of the hollow blade. During the drying process of the material, the hollow shaft with hollow blades heats the material and stirs the material at the same time, so as to update the heating surface. The permeability of heat transfer oil is very strong (about 50 times that of steam). If you choose a packing globe valve, gate valve or ball valve, it is very easy to leak out, resulting in waste of hot oil and soiling of equipment and ground, while the bellows structure can be completely zero. leaks, and there are no wearing parts. The general filler is processed and formed by graphite. If the purity of graphite is not enough, its oil resistance will become very poor. When the heat transfer oil is immersed in the graphite filler, some impurities in the graphite are easily dissolved by the heat transfer oil, resulting in the graphite powder. The graphite packing cannot achieve the sealing effect, which is the main reason for the frequent leakage of the packing valve. It is a continuous conduction heating dryer. The heating medium is steam, hot water or heat transfer oil. The heating medium is passed into the shell jacket and the two hollow blade shafts to heat and dry the material by conduction heating. The structure of the hollow blade shaft is different for different materials. The generation of granular tar scale and coke scale mostly occurs when the heat transfer oil in the furnace tube is in a stagnant flow. At this time, the boundary oil film flowing along the pipe wall will become thicker. When the thermal strength increases and the temperature of the pipe wall exceeds the allowable temperature of the oil film, the heat transfer oil will undergo reactions such as cracking, polymerization, coking, and carbon deposition. In addition to pasty glue and grease, it will appear alone in the heat-conducting oil heating system with light scaling. Generally, it is composed of more than two types of grease. For example, the outer layer is glue and grease, the middle layer is tar scale, and the inner layer is coke scale.
