Pulse vacuum single cone dryer

The vacuum single-cone dryer developed by Wuxi Shuangrui is a highly efficient and multi-functional fully enclosed vertical vacuum drying equipment integrating vacuum distillation, crushing, powder mixing and drying. The drying efficiency of the fully enclosed vertical vacuum helical ribbon dryer is 3 to 5 times that of the double-cone rotary vacuum dryer and vacuum box dryer of the same specification. The vacuum single cone dryer, combined with a special drying process, can adapt to the drying of materials with high viscosity, poor heat penetration, and prone to balling and clumping.

The pulse vacuum single cone dryer is equipped with a heating cone and a heating jacket. The heat source is hot water, heat transfer oil or low-pressure steam, which keeps the inner wall of the cone at a certain temperature. The variable frequency speed control motor drives the single-helical ribbon agitator to rotate through the parallel helical gear reducer, causing the material to rotate along the conical cylinder and be lifted from bottom to top. After reaching the highest point, the material automatically flows to the center of the vortex and returns to the bottom of the conical cylinder due to the effect of gravity and inertia. The entire process forces the material to be heated inside the conical cylinder, with relative convection and mixing. The heat diffuses among the materials. Make the material move in an irregular reciprocating motion in all directions to complete the high-frequency heat transfer exchange between the material and the single-screw ribbon and the surface of the cylinder wall, achieving the heating and drying effect in a short time. This enables the moisture inside the material to continuously evaporate. Under the action of the vacuum pump, the water vapor is drawn out by the vacuum pump. If it is necessary to recover the liquid, a condenser or a recovery liquid storage tank can be added for recovery. After the drying is completed, open the discharge valve at the bottom to discharge the material.

Process flow chart of pulse vacuum single cone dryer

The main structure of the pulse vacuum single cone dryer

The single-cone vacuum dryer is composed of components such as a motor, a reducer, a frame, a mechanical seal, a metal sintered mesh filter, a hollow twin-screw belt agitator, a conical cylinder with jacketed heating, and a discharge valve.

(1) Transmission and sealing section: Composed of an electric motor, a reducer, a frame and a mechanical seal.

① Motor: A variable frequency speed regulation motor is adopted, and the speed can be adjusted as needed during operation.

② Reducer: FAF series helical gear reducer, featuring smooth and reliable operation, low noise and long service life.

③ Frame: Self-designed, with high manufacturing precision. It is equipped with two pairs of roller bearings inside, which can adjust the height of the agitator and the radial swing.

④ Mechanical seal: Single-end face sanitary type with material receiving and flushing cavity, with good sealing performance.

(2) Agitator: The hollow agitator shaft is respectively connected to the hollow helical ribbon with support rods. The upper and lower ends connected to the hollow helical ribbon form a circuit through which the heat medium can pass with hollow support rods. To ensure that the material does not adhere to the cylinder wall, the gap between the screw ribbon and the cylinder wall is very small.

(3) Tank body: This part is composed of the upper end head, conical cylinder body, vacuum filter, discharge valve, etc.

① Upper head: Bears the transmission part and the agitator; The inner surface pipe openings all have arc transitions. All materials in contact with the materials are 316L. The process pipe openings are as follows: DN400 sanitary manhole, pressure gauge, explosion-proof sight light, sight glass opening, feed opening, cleaning opening, vacuum opening, etc.

② Lower cone with heating jacket: The inner surface is smooth and free of dead corners, which enables the material to be fully dried. When discharging, with the help of the rotation of the stirrer, the discharge is rapid and clean.

③ Filter: Metal sintered mesh is adopted, featuring high filtration accuracy and large filtration area. And an exhaust port is set at the vacuum outlet to regenerate the filter by back-blowing compressed air during exhaust.

Structure diagram of the internal heating helical ribbon single cone vacuum dryer equipment

Structure diagram of single-cone spiral high-efficiency mixing dryer equipment

Process features of pulse vacuum single cone dryer

The drying and mixing of powder is an important link in the production of active pharmaceutical ingredients. Therefore, the selected drying and mixing equipment is the guarantee of the final product quality and also the key to determining the production and operation costs. The vacuum single cone dryer newly developed and manufactured by Wuxi Sunray, with its unique structure and outstanding advantages, has improved the drying technology in China's chemical and pharmaceutical industries.

The selection of dryers needs to meet the specific requirements and characteristics of various products and processes. Its main contents are as follows:

Most of the crude raw materials processed in production are heat-sensitive, so lumps often occur during the drying process. Therefore, it is necessary to shorten the drying time as much as possible and improve the drying efficiency.

In the production of materials, the purity of the circulating gas used in the drying process can have a significant impact on the quality of the materials. This equipment adopts a unique gas supply technology, minimizing the impact of gas on the drying process. From the perspective of operational economy, it is hoped that all process pipelines can be fixedly installed, thereby saving the rotational space required by similar double-cone dryers.

③ To ensure the continuity of the entire process and simultaneously reduce the leakage loss of materials, the solid discharge flow rate of the dryer is controllable. This can reduce the workload of manual operation and loading/unloading in the clean area and prevent the phenomenon of materials being washed out.

(2) Structure and characteristics of vacuum single-cone dryer

The working process of the vacuum single-cone dryer is intermittent batch operation. After the wet materials enter the silo, they are heated through the jacket of the cylinder wall and the interior of the propeller, increasing the heating area to 140% of the entire container area, thereby heating and drying the materials. And select the corresponding conical drying mixer model (working volume) to achieve the ideal drying effect. The mixed dryer with an up-drive structure not only has highly efficient drying and mixing capabilities, but also features ample space, making it more convenient for users to carry out maintenance and repair.

② Smooth operation and protection of crystal form

The vacuum single cone dryer does not use any auxiliary tools during the drying and mixing process. It only utilizes the stirring of the heating helical ribbon inside the cone. This ensures that the materials are not only lifted by the stirring screw but also continuously sheared and dispersed, guaranteeing that all materials in the silo can achieve sufficient movement. Moreover, it enables the materials to be lifted by the slurry, It is not subjected to any other external force of compression, avoiding the ineffective friction between the powder and the equipment as well as between the powder grains. Ineffective friction is often the main factor leading to the destruction of the material crystal form. This is also the fundamental reason why the vacuum single cone dryer can maintain the integrity and undamage of the material crystal form during the operation process.

③ Top drive eliminates the possibility of contamination to the product caused by shaft seals

By adopting top drive, compared with bottom drive, this equipment can avoid the following drawbacks: the stirring paddle must be disassembled with dedicated equipment for cleaning and maintenance, and the sealing parts of the stirring paddle shaft are difficult to achieve true sealing, lacking quality assurance.

④ Low operating energy consumption cost and high mixing efficiency

It is driven by a motor and features a unique design. The screw driven by the motor's operation is used to lift materials, without the energy consumption for discharging separately. It is particularly worth noting that in the process of mixing and drying, the traditional mixing and drying equipment provides a belt-type stirring paddle. The working principle is that when the stirring movement occurs, the moving material is like a whole. A large amount of energy consumption is used for the circular motion of the entire material. Therefore, the drying efficiency provided by this stirring is low. The vacuum single-cone dryer provides a conical internal heating helical ribbon stirring. The entire stirring paddle moves in a circular motion around the axis of the conical silo, ensuring that the materials in different parts of the entire container can be stirred. As the helical ribbon stirring proceeds, the materials at the bottom of the silo are gradually lifted to the upper part of the container and then fall naturally, and this cycle repeats. This stirring mode ensures that the materials inside the container are thoroughly and evenly mixed, eliminating the possibility of material caking during the drying process and significantly enhancing the efficiency of material mixing and drying. Moreover, it has the advantages of a wide range of processing capacity and low energy consumption per unit mass.

⑤ Simple operation and convenient maintenance

The mechanical structure of the vacuum single-cone dryer is simple and effective, and it is easy for operators to understand. The simple button control makes the operation process very simple. Some maintenance and repair work can even be completed smoothly and quickly without professionals. The manholes set up can easily adjust and maintain the moving screw without complex disassembly. This equipment has very few vulnerable parts. The bearing box and other drive units are set on the top of the silo. Users can easily disassemble the entire unit during maintenance, and the space for the drive units on the top is also relatively ample.

(3) Comparison of advantages with conventional vacuum dryers - Taking a 2000L dryer of the same volume as an example

Select the correct rotor for the pulse vacuum single cone dryer

One of the most important components in the design of a vacuum dryer is its agitator. To select the right agitator with the correct characteristics, it is necessary to understand the properties of the feed and the vacuum drying process results you hope to achieve.

(1) Screw agitator

The screw agitator is a well-proven design suitable for drying powders, filter cakes, pastes and slurries under atmospheric or vacuum conditions. It is almost applicable to all products, even sticky ones. Due to its outstanding performance in conveying products along the container wall, it ensures the realization of an efficient drying cycle and can be applied to dryers with a drying capacity of over 20,000 liters.

(2) Paddle agitator

When the viscosity of the product is relatively low, a paddle agitator can be used to achieve the best temperature control and product transportation between the rotor blade tips and the container walls. When necessary, it can be used to fully mix the product after the drying cycle.

(3) Belt agitator

For products with low initial moisture content and good fluidity, belt agitators are a better alternative to screw agitators. It can stir a larger batch of products at one time, thereby achieving better heat transfer and reducing drying time.

Technical parameters of pulse vacuum single cone dryer

On-site photos of the pulse vacuum single cone dryer