Drying equipment is widely used in industrial testing

Drying equipment is widely used in industrial testing and many fields require its use. Similarly, drying equipment also plays an important role in the pharmaceutical industry. Today, the author will introduce the application of eight types of drying equipment in the chemical and pharmaceutical industry. An analysis of the application of eight types of drying equipment in the chemical and pharmaceutical industry.

(1) Belt dryer

A belt dryer consists of several independent unit segments. Each unit segment includes a circulating fan, heating device, separate or shared fresh air intake system, and exhaust system. The operating parameters of drying medium quantity, temperature, humidity, and exhaust gas circulation can be independently controlled to ensure the reliability of the dryer operation and optimize the operating conditions. The operation of the dryer is flexible, and the wet material is fed. The drying process is carried out in a completely sealed box with good working conditions, avoiding the leakage of dust. Used for drying sheet, strip, and granular materials with good breathability, especially suitable for dehydrated vegetables, traditional Chinese medicine slices, and other materials with high moisture content but not allowed to have high temperature.

(2) Drum scraper dryer

The drum scraper dryer is a continuous operation equipment that uses a rotating cylinder to dry liquid or strip materials attached to the outer wall of the cylinder through heat conduction. The liquid that needs to be dried flows from the high-level tank into the receiving tank of the drum dryer. The drying drum rotates at the specified speed under the drive of the transmission device. The material is formed into a film on the drum wall by a cloth film device. The heating medium is continuously introduced into the cylinder, heating the cylinder body. The moisture of the material film is vaporized by heat transfer from the cylinder wall. Then, the material that meets the drying requirements is scraped off by a scraper and transported by a screw to the storage tank for packaging. The moisture removed by evaporation can be introduced into the corresponding treatment device through a sealed hood depending on its properties; Generally, it is water vapor, which can be directly released into the atmosphere through the exhaust pipe on the top of the hood. This machine is mainly used for processing liquid materials, which can be heated and dried with steam, hot water or hot oil, or cooled and solidified with cold water. According to different material properties and process requirements, feeding methods such as immersion, spray, and grinding can be used.

(3) Hollow blade dryer (blade dryer)

Hollow blade dryer, also known as 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 rotating joint for introducing heat medium. The heat required for drying moisture is conducted to the material by the inner wall of the W-shaped groove with a jacket and the hollow blade wall. During the drying process, the hollow shaft with hollow blades heats the material while stirring it, thereby updating the heating surface. It is a continuous conduction heating dryer. The heating medium is steam, hot water, or thermal oil. The heating medium is introduced into the shell jacket and two hollow blade shafts to heat and dry the material through conduction heating. The structure of hollow blade shafts varies for different materials. This machine is suitable for processing various materials with good thermal stability such as paste like, granular, and powdery forms. It can also dry heat sensitive materials and recover solvents during the drying process under special conditions. Commonly used for drying or cooling materials such as carbon black, light calcium carbonate, titanium dioxide, barium carbonate, cyanuric acid, gypsum, clay, manganese dioxide, nylon and polyester chips, polyethylene, polypropylene (recycled solvents), etc.

(4) Vacuum rake dryer

The dry material is added from the middle of the shell of the vacuum rake dryer. Under the stirring of the constantly rotating rake teeth, the surface of the material constantly updates when it comes into contact with the shell wall. The dried material is indirectly heated by steam (or hot water, thermal oil), and the moisture in the material evaporates. The vaporized moisture is promptly extracted by the vacuum pump. The dried material is indirectly heated by the heat carrier, causing the moisture in the material to vaporize. The vaporized moisture is promptly discharged by the vacuum pump.

Due to the high vacuum level during operation, generally within the range of 400-700mmHg, the surface water vapor pressure of the dried material is much higher than the water vapor pressure in the evaporation space inside the dryer shell. This is conducive to the discharge of internal and surface moisture in the dried material, and facilitates the movement of water molecules in the dried material, achieving the purpose of drying. The vacuum rake dryer is suitable for materials that are sensitive to heat, prone to oxidation at high temperatures, or prone to hardening during drying, as well as materials that require the recovery of steam emitted during drying. Typical dry materials include sodium acrylate CMC、 Phthalocyanine blue, dye intermediates, carboxymethyl starch, maltodextrin, anthraquinone sulfonic acid, etc.

(5) Double cone rotary vacuum dryer

The body of the double cone rotary vacuum dryer is slightly olive shaped, with covers at both ends and two shafts in the middle to support the body. The device has a jacket for heating, and during drying, the device can rotate, allowing the material to frequently come into contact with the device wall, overcoming the disadvantage of low thermal efficiency in vacuum ovens where the material mainly relies on the heating cylinder for conduction. Rotary vacuum dryers have been widely used in fine chemicals, pharmaceuticals, and other fields, but are not suitable for materials with high viscosity or strong adhesion during the rotary process. This equipment is mainly used for the concentration, mixing, drying, and low-temperature drying of powdered, granular, and fibrous materials in industries such as pharmaceuticals, chemicals, and food (such as biochemical products). It is more suitable for drying materials that are easily oxidized, volatile, highly thermally sensitive, toxic, and do not allow the destruction of crystals.

(6) Spray dryer

Spray drying is widely used in liquid forming and drying industries. It is especially suitable for generating powdery and granular solid products from solution, lotion, suspension and paste liquid raw materials. Therefore, when the particle size distribution, residual moisture content, bulk density and particle shape of the finished product must meet high standards, spray drying is a better process.

(7) Vacuum oven

Due to the reduced pressure, the evaporation temperature of volatile compounds in the material can be lowered, making it suitable for drying various thermosensitive and easily oxidizable materials. This device is often a cylindrical or other vacuum operated casing, which is heated by electric or hot water, or thermal oil through a heating plate or heating tube. It is suitable for small batch intermittent production.

Oven is a universal drying equipment with a wide range of applications. It belongs to the tray type intermittent drying equipment and is used in pharmaceuticals, chemicals, and food. Heating solidification, drying and dehydration of materials and products in light industry, heavy industry and other industries. Such as raw materials, medicinal herbs, traditional Chinese medicine decoction pieces, extracts, powders, granules, granules, water pills, packaging bottles, pigments and dyes, dehydrated vegetables, dried fruits and vegetables, sausages, plastic resins, electrical components, baking paints, etc.

(8) Rotary flash dryer

The dried material enters the drying chamber through a spiral input device and is crushed by the stirring blade at the lower part of the dryer. The crushed material comes into full contact with hot air and flows upward and dries under the dual action of the stirring blade and airflow distributor. The material that passes the screening of the classifier and meets the particle size and humidity requirements is rotated downward for drying until it is qualified.

Product features: Fast drying speed. The dryer can be completed in 1-10 seconds; The retention time of materials can be adjusted. Adjustable between 1-500s, suitable for drying thermosensitive materials; Multiple feeding devices are available for selection, ensuring continuous and stable feeding without any bridging phenomenon; The high circumferential gas velocity in the drying chamber results in a short residence time of the material, effectively preventing it from sticking to the wall and causing thermal sensitive materials to deteriorate; The drying chamber is equipped with a grading ring and swirl blades, and the material fineness and final moisture content can be adjusted and controlled; High drying strength.