Continuous Drying Line: A Detailed Explanation of High-Efficiency Automated Drying Solutions

A continuous drying line is an automated drying equipment based on the technology of uninterrupted conveying + precise temperature control. Through conveying devices such as conveyer belts, chains, or mesh belts, materials are continuously fed into a closed drying chamber, where they undergo dehydration and drying in a pre-set environment of temperature, humidity, and airspeed. Finally, it realizes the full-process automated operation of "feeding - drying - discharging". It breaks through the limitations of traditional batch-type drying equipment, such as "batch processing and low efficiency", and is widely used in large-scale production scenarios in various industries. It is one of the core pieces of equipment in modern industry for improving drying efficiency and ensuring the stability of product quality.

I. Core Composition and Working Principle

The structural design of a continuous drying line centers on the two core goals of "high-efficiency conveying" and "uniform drying", and it mainly consists of five systems:

Conveying System

The core component is a high-temperature-resistant conveyer belt (common materials include stainless steel mesh belts, Teflon mesh belts, chain-type pallets, etc.). The appropriate type is selected according to the material form (granular, flaky, block, liquid, etc.) to ensure stable conveying of materials without adhesion. The conveying speed can be adjusted by a variable-frequency motor to meet the drying time requirements of different materials.

Drying Chamber

It is usually made of stainless steel through welding, with good airtightness and thermal insulation, which can effectively reduce heat loss. The interior of the chamber is divided into multiple temperature zones (such as preheating zone, constant temperature zone, and cooling zone). Each temperature zone has independent temperature control, which meets the "gradient drying" needs of materials (for example, food drying requires low-temperature dehydration first, then high-temperature sterilization to avoid local scorching).

Temperature Control System

It is composed of heating devices (electric heating tubes, gas burners, heat pump units, etc.), temperature sensors, and intelligent controllers, which can precisely control the temperature inside the chamber within a range of ±1℃. Some high-end equipment supports linkage with the PLC (Programmable Logic Controller) system to record the temperature curve in real time, facilitating production traceability.

Air Circulation System

It includes centrifugal fans, air ducts, and air nozzles. Through the design of "upper air supply + lower air exhaust" or "side air supply", the hot air flows uniformly inside the chamber, avoiding uneven drying caused by local temperature differences. At the same time, it is equipped with a dehumidification device to timely discharge the water vapor evaporated from materials and maintain stable humidity inside the chamber.

Electrical Control System

It integrates a touch screen, emergency stop button, overload protection, alarm device, etc. The operation interface is simple and intuitive, allowing the setting of parameters such as drying temperature, conveying speed, and dehumidification capacity. It supports switching between automatic/manual modes, facilitating equipment debugging and fault handling.

Its working process can be summarized as: Material Feeding → Conveying by the Conveying System → Preliminary Dehydration in the Preheating Zone → In-depth Drying in the Constant Temperature Zone → Cooling and Shaping in the Cooling Zone → Finished Product Discharging. The entire process requires no manual intervention and realizes 24-hour continuous operation.

II. Applicable Industries and Typical Application Scenarios

With the advantages of "high efficiency, stability, and scalability", continuous drying lines have penetrated into various industries, and the equipment design varies in different scenarios to meet specific needs:

Food Processing Industry

It is used for fruit and vegetable dehydration (such as raisins, dehydrated vegetables), meat drying (beef jerky, cured meat), grain drying (rice, corn), and baked food production (biscuits, potato chips), etc. The equipment must meet food-grade standards (304 stainless steel for materials, food-grade silica gel for seals), and some need to be equipped with ultraviolet sterilization functions.

Chemical Industry

It is suitable for drying granular chemical raw materials (such as plastic particles, chemical fertilizers), flaky coatings, and curing of adhesives. Corrosion-resistant materials (such as 316L stainless steel) must be used, and explosion-proof devices should be equipped (for flammable and explosive materials).

Electronics Industry

It is applied to the drying of PCB (Printed Circuit Board) boards, moisture-proof treatment of electronic components, and drying of battery pole pieces. It requires high cleanliness inside the chamber (Class 1000 cleanroom level) to avoid dust pollution, and the temperature control accuracy must reach ±0.5℃.

Textile and Leather Industry

It is used for fabric setting, dye drying, and leather dehydration. The equipment needs to have a large conveying width (up to 2-3 meters), and the air circulation system must prevent fabric wrinkling. Some equipment needs to be equipped with tension adjustment devices.

Pharmaceutical Industry

It is used for drying Chinese herbal pieces (such as honeysuckle, wolfberries), drying of medicinal capsules, and drying of medical devices after disinfection. It must comply with GMP (Good Manufacturing Practice) certification standards, with no sanitary dead corners in materials and easy cleaning and disinfection.

III. Core Advantages and Key Considerations for Selection

(I) Core Advantages Compared with Traditional Drying Equipment

Significant Efficiency Improvement

Under the continuous operation mode, the processing capacity per unit time is 3-5 times that of batch-type equipment. For example, a food drying line can handle 5-10 tons of fresh fruits and vegetables per day, greatly shortening the production cycle.

Stable Product Quality

The precise temperature control and uniform air circulation design ensure consistent drying degree of materials in the same batch, avoiding quality fluctuations caused by manual operations. At the same time, it reduces material loss during handling (traditional batch-type equipment requires multiple loading and unloading, with a loss rate of about 5%, while that of continuous-type can be reduced to less than 1%).

Reduced Energy Consumption Cost

The closed chamber and thermal insulation design reduce heat loss, with a thermal efficiency of 70%-85% (compared to 50%-60% for batch-type equipment). Some heat pump-type drying lines can utilize heat energy in the air, reducing energy consumption by 40%-60% compared to electric heating.

Labor Cost Savings

The fully automated operation only requires 1-2 personnel for feeding and inspection, while traditional equipment needs 5-8 personnel to work in shifts. It can save 100,000-200,000 yuan in labor costs per year.

(II) Key Indicators for Equipment Selection

Material Characteristics

Select the appropriate model according to the material form (dust-proof measures are needed for powdery materials, and pallets are required for liquid materials), moisture content (materials with high moisture content require an extended drying chamber or additional temperature zones), and heat sensitivity (for example, biological products require low-temperature vacuum drying, so equipment with a vacuum system should be selected).

Production Capacity Requirements

Determine the width and length of the equipment based on the "daily processing capacity". For example, for a daily processing capacity of 1 ton of materials, a drying line with a width of 1 meter and a length of 8-10 meters can be selected; for a daily processing capacity of more than 5 tons, a drying line with a width of 2 meters and a length of 15-20 meters is required.

Heat Source Type

Select according to local energy costs: electric heating can be chosen in areas with low electricity fees; gas heating is suitable for areas with low gas prices; heat pump units are preferred in warm southern regions due to their energy-saving and environmental protection features.

Environmental Requirements

Some regions have strict requirements for exhaust gas emissions (such as in the chemical and food industries). Equipment equipped with exhaust gas treatment devices (such as activated carbon adsorption, UV photolysis) should be selected to avoid odor pollution.

IV. Daily Maintenance and Common Fault Handling

To extend the service life of the equipment and ensure stable production, the following maintenance work should be done well:

Daily Maintenance

• Check the tightness of the conveyer belt (to avoid slipping or breaking).

• Clean the residual materials inside the chamber (to prevent mildew or blockage of air ducts).

• Check whether the temperature sensor is normal (calibrate with a thermometer).

Weekly Maintenance

• Clean the air nozzles and air ducts (to avoid dust accumulation affecting airspeed).

• Check whether the heating tubes are damaged (for deformation or leakage).

• Lubricate the conveying chain (using high-temperature lubricating oil).

Monthly Maintenance

• Check whether the thermal insulation layer is damaged (to avoid heat loss).

• Test the emergency stop button and alarm device (to ensure the normal operation of safety functions).

• Calibrate the temperature control system (compare the actual temperature with the displayed temperature).

Common Faults and Handling Methods

Uneven Drying

This may be caused by blocked air nozzles or faults in the air circulation fan. It is necessary to clean the air nozzles or replace the fan; it may also be due to excessively fast conveying speed, so the speed should be reduced appropriately.

Failure to Reach the Required Temperature

Check whether the heating device is damaged (such as open circuit of the electric heating tube), whether the parameters of the temperature controller are set correctly, and whether the chamber has good airtightness (such as damaged door curtains).

Conveyer Belt Deviation

Adjust the tension wheels on both sides of the conveyer belt to ensure uniform stress; if the conveyer belt is severely worn, it should be replaced in time.