Development of new internal heating double cone vacuum dryer

Double cone vacuum dryer has long been widely used in pharmaceutical, chemical and food industries, because of its advantages of energy saving and simple structure, it is favored by the majority of customers. But simple structures also have negative effects. First of all, there is no active and effective stirring and dispersing function, so it can only dry the non sticky loose materials. However, when the water content is high, the wet mass will roll with the cone, which will affect the contact heat transfer between the center of the wet mass and the heating surface. Secondly, the four outer jacket heating structure is not conducive to the large-scale dryer. The double cone dryer belongs to indirect heating dryer, and the large-scale should be mainly reflected in the amount of heating area, because the heating area of the double cone is directly proportional to the diameter and the first power of the length, but its volume is proportional to the horizontal square of the diameter. Therefore, with the enlargement of the diameter of the biconical cone, the ratio of the volume to the area of the cone is also increasing. Taking 0.1 M 3, 1 m 3 and 10 m 3 vertebral bodies as examples, the heating area ratio per unit volume is about 1:0.5:0.2. This is enough to show that the drying efficiency will be greatly reduced after large-scale, which seriously damages the economic significance of large-scale.

As a matter of fact, the double cone dryer currently in use has the hidden danger of foreign matters polluting the products, which is in conflict with the requirements of GMP. This is because the fixed vacuum suction pipe inserted into the double cone body is sealed by the stuffing box, so there is naturally mechanical friction and wear foreign matters, and the cone is in operation. There is vacuum and wear in the cone, and the foreign body must be inhaled into the cone body.

In order to ensure the quality of heat sensitive products, the conventional double cone vacuum dryer generally uses hot water lower than the product heat sensitive temperature as the heat source. Because the sensible heat of hot water is used, there must be temperature difference between the inlet and outlet of hot water. Therefore, on the one hand, the temperature of hot water at the inlet is lowered due to the limitation of thermal sensitive temperature, on the other hand, the driving force of drying is seriously weakened by the influence of temperature difference between inlet and outlet.

Our company to improve and customer service double cone vacuum dryer existence of these problems. A large-scale double cone vacuum dryer with internal heating was developed by introducing foreign advanced technology and combining with many years of practical experience

The new double cone dryer makes full use of the huge space in the double cone body. The hollow thin heating plate is set on the inner wall of the cone in the clockwise rotation direction, and the inner part of the heating plate is connected with the double cone heating jacket. It is impossible for the built-in heating plate to dissipate heat to the outside, so the new double cone dryer is more energy-saving than the conventional double cone dryer. The heating area per unit volume of large-scale internal heating double cone dryer can reach 5.5-6.5m2/m3, which is equivalent to the level of 1.0-1.5m3 conventional small-sized double cone dryer, which makes the double cone dryer large-scale has practical significance.

The heating plates in the double cone body are divided into 8 groups. The heating plates are staggered and slightly inclined along the rotation direction. According to the physical properties of the dry materials, the edges of the heating plates are used as rounded corners or acute angles, so that the wet materials are dispersed and mixed by the heating plate under the action of gravity, so as to avoid uneven heating due to the agglomeration of wet materials. After heating the heating plate group and adding the cone, the dispersing and mixing conditions of the drying materials are greatly improved, the heat transfer is promoted and the efficiency of the dryer is improved.

The layout of the inner heating plate in the inner heating double cone dryer fully considers the needs of equipment cleaning. Two manholes and two cleaning aisles with a spacing of half meter are set up. The walking through and the rotary axis are parallel and pass through the manhole. Welding on the walking cone surface has heating effect, and the auxiliary plate can also be used as a step for cleaning. The welding position between the inner heating plate and the conical surface is round, and there is no dead angle in the cone, so the cleaning is reliable and convenient.

In order to eliminate the hidden danger of wearing foreign matters polluting the products, the vacuum suction pipe of the dryer is equipped with a double sealing mechanism, and a mechanical seal box and a washable dirt collecting chamber are added after the packing seal box to ensure that the mechanical wear does not pollute the products and make the dryer truly meet the requirements of GMP.