Vegetable Dehydration Machine

Vegetable dehydrator is an industrial equipment that removes 90% -95% moisture from vegetables through technologies such as hot air circulation, vacuum low-temperature or condensation dehumidification. The core principle is based on water evaporation kinetics: when the ambient temperature rises to 60-85 ℃ and the relative humidity is below 40%, the free water inside vegetable cells evaporates at a rate of 0.5-2g/(cm ² · h), combined with controllable wind speed (0.5-3m/s) to accelerate water migration and achieve efficient dehydration. Typical equipment such as TT-DR500 dehydrator uses a 21.5kW power motor to drive a 900rpm high-speed fan, coupled with an 8000 × 2000 × 2500mm large-sized drying chamber, with a single batch processing capacity of 400-500kg, suitable for large-scale dehydration of root, stem and leaf vegetables such as carrots and spinach.

2、 Technical characteristics and professional parameters

1. Multi mode drying system

Hot air circulation drying: The air temperature is controlled at 65-80 ℃ through a resistance heater, and a vertical airflow is formed with an axial fan to increase the dehydration efficiency of potato chips to 1.2kg/(kW · h). Experimental data shows that this mode has a retention rate of 82% for vitamin C, which is 35% higher than the traditional sun exposure method.

Vacuum low-temperature drying: Under a vacuum environment of -0.08MPa, the drying temperature is reduced to 45-55 ℃, and the diffusion of moisture is accelerated by pulsed microwave assistance (2450MHz, 500W). Taking shiitake mushrooms as an example, this technology achieves a polysaccharide retention rate of 91%, which is 18% higher than that of hot air drying.

Condensation dehumidification and drying: A two-stage condensation system (first stage evaporation temperature of 5 ℃, second stage evaporation temperature of -10 ℃) is used to maintain a constant humidity of 30% -35% in the drying chamber. When dehydrating broccoli, this technique results in a chlorophyll retention of 0.8mg/g and a color L * value maintained in the range of 45-50, which meets the GB/T 23783-2009 standard for fruit and vegetable crisps.

2. Intelligent control system

PLC+SCADA architecture: Equipped with Siemens S7-1500 series PLC, process parameter visualization is achieved through a 10 inch touch screen. The system can store 50 sets of drying curves and supports PID closed-loop control of temperature, humidity, and wind speed, with fluctuation ranges controlled within ± 1 ℃, ± 3% RH, and ± 0.2m/s, respectively.

Infrared moisture detection: Integrated near-infrared spectrometer (wavelength range 900-1700nm), real-time monitoring of vegetable moisture content. When the deviation between the detected value and the set value is greater than 0.5%, the system automatically adjusts the heating power to ensure that the dehydration uniformity CV value is ≤ 5%.

Remote operation and maintenance module: Connected to the enterprise cloud platform through 4G/5G networks, it achieves equipment status monitoring, fault warning, and process optimization. The application case of a dehydrated vegetable processing plant shows that this function improves the overall equipment efficiency (OEE) to 88% and reduces maintenance costs by 27%.

3. Energy saving and environmental protection design

Heat pump recovery system: Adopting a closed heat pump cycle, the exhaust heat recovery rate is increased to 75%. Taking a factory that processes 10 tons of vegetables per day as an example, this technology reduces unit energy consumption to 0.35 kWh/kg, which is 58% more energy-efficient than traditional electric heating equipment and reduces annual CO ₂ emissions by 120 tons.

Variable frequency drive technology: The motor is equipped with ABB ACS880 series frequency converter, which automatically adjusts the speed according to the load. In the light load stage (load rate<30%), the motor efficiency still remains above 92%, saving 22% energy compared to fixed frequency drive.

Wastewater treatment unit: Integrated membrane bioreactor (MBR) for advanced treatment of cleaning wastewater. After testing, the effluent COD is ≤ 50mg/L and SS is ≤ 10mg/L, meeting the first level standard of GB 8978-1996 "Comprehensive Wastewater Discharge Standard", and can be reused for equipment cleaning.

1. Daily cleaning process

After the shift ends:

Empty the residual materials in the drying chamber, rinse the inner wall with a high-pressure water gun, and focus on cleaning the vegetable residue between the fins of the heat exchanger.

Use food grade sodium hydroxide solution (pH=12) to cycle and clean for 10 minutes to remove protein precipitates.

Wipe the touch screen and operation panel with 75% alcohol to prevent cross contamination.

Weekly deep maintenance:

Disassemble the fan impeller and perform ultrasonic cleaning (frequency 28kHz, power 500W) to remove oil stains.

Check the surface scaling of the heating tube. When the thermal efficiency drops to 80% of the initial value, it is necessary to use citric acid solution (concentration 5%) for acid washing.

2. Maintenance of key components

Maintenance of heat pump compressor: Check the lubricating oil level of the compressor every month. When the oil level is lower than 1/3 of the sight glass, supplement POE refrigerant oil. Adopting the Valley Wheel ZR series compressor, with a normal service life of 40000 hours, it is recommended to replace it preventively every 2 years.

Frequency converter parameter calibration: Use FLUKE 435 series power quality analyzer to detect the output voltage waveform every quarter. When the total harmonic distortion (THD) is greater than 5%, adjust the carrier frequency to above 8kHz.

Transmission system adjustment: Check the belt tension every six months, and maintain the initial tension at 180N ± 10N by adjusting the motor base bolts to prevent slipping or deviation.

3. Seasonal maintenance points

Summer overheating prevention: When the ambient temperature is above 35 ℃, an axial flow fan (air volume of 5000m ³/h) should be installed on the top of the equipment to forcibly dissipate heat. At the same time, check the water level of the cooling tower daily to ensure that the circulating water flow rate is ≥ 3m ³/h.

Winter antifreeze cracking: When the ambient temperature is less than 5 ℃, the heat pump system and water pipes need to be emptied of accumulated water, and -15 ℃ antifreeze solution (ethylene glycol accounts for 45%) should be injected. Wrap insulation cotton around fan bearings and other components to prevent freezing damage.