Summer Maintenance Of Twin Screw Fish Feed Production Line (1)

When the twin-screw fish feed production line is running in a high temperature and high humidity environment in summer, the various systems of the equipment are prone to problems such as temperature increase, increased wear of components, and moisture in raw materials, which affect production efficiency and stability. The following is a detailed introduction to the key points of summer maintenance and operation suggestions from multiple dimensions:

1. Inspection of screw and barrel of twin-screw extruder

Wear detection: During summer production, the wear speed of screw and barrel is accelerated due to high temperature softening. The machine needs to be stopped every week to check whether there are scratches, grooves or material residues on the screw thread and the inner wall of the barrel (especially the oil components in fish feed are easy to adhere and coke). The degree of wear can be judged by measuring the screw diameter and barrel inner diameter deviation (allowable error ≤0.5mm), and it needs to be replaced in time if it exceeds the threshold.
• Lubrication management: The screw bearing uses high-temperature resistant lithium-based grease (such as NLGI 2#). In summer, the lubrication cycle needs to be shortened to every 8 hours to avoid dry grinding of the bearing due to the thinning of the grease at high temperature. After lubrication, the screw needs to be manually turned to confirm that there is no sticking or abnormal noise.

2. Twin-screw fish feed production line main engine gearbox and reducer maintenance
• Oil temperature monitoring: The operating temperature of the gearbox should be controlled below 60℃. In summer, a cooling fan can be installed or high-viscosity gear oil (such as ISO VG 220) can be used. The box temperature is detected with an infrared thermometer every shift. If it exceeds 70℃, the machine needs to be stopped to check the oil level (should be at 1/2-2/3 of the window) and oil quality (blackening and emulsification need to be replaced immediately).
• Gear meshing inspection: Remove the observation hole cover every month to check whether there is pitting or broken teeth on the gear tooth surface. The meshing clearance should be kept at 0.1-0.3mm. If the clearance is too large, the gear shaft position needs to be adjusted or the gear needs to be replaced.

1. Strengthening of cooling system
• Water circulation system:
o Cooling water temperature needs to be ≤32℃. In summer, the water supply flow of cooling tower can be increased (recommended ≥120% of design flow), and cooling tower filler and pipe scale should be cleaned regularly (cleaned once every 2 weeks with 5% citric acid solution) to avoid heat exchange efficiency reduction.
o Barrel cooling jacket is prone to poor heat dissipation due to scaling. High-pressure water gun (pressure ≤10MPa) can be used to flush the jacket channel to ensure that the outlet water temperature difference is ≥5℃ (when the inlet water is 30℃, the outlet water should be ≤35℃).
• Mold cooling: The diameter of the fish feed mold hole is usually 1-5mm. In summer, the mold cooling water pressure should be maintained at 0.3-0.5MPa and the water flow rate should be ≥1.5m/s to prevent the material from gelatinizing at high temperature in the mold hole. Use compressed air (pressure 0.6MPa) to blow away the residual material in the mold hole every week.
2. Adjustment of the heating system
• Temperature control calibration: In summer, when the ambient temperature is high, the set temperature of the barrel heating section can be reduced by 5-10℃ (if the original setting is 120℃, it can be adjusted to 110-115℃) to avoid overheating and denaturation of the material. At the same time, use a thermocouple thermometer to calibrate the deviation between the actual temperature of each section and the instrument display (±3℃ is allowed). If it exceeds, the heating rod or temperature controller needs to be replaced.
• Heating coil maintenance: Check whether the heating coil terminal is loose due to high temperature oxidation, polish the terminal with sandpaper every month, and apply conductive paste to prevent local overheating caused by poor contact.

1. Moisture-proof and heat-dissipating electrical cabinets for fish feed production line
• Environmental control: Install a temperature-controlled dehumidifier in the electrical cabinet (humidity setting ≤60% RH). Check whether there is condensed water in the cabinet before starting the machine every day in summer. Moisture-proof silica gel desiccant can be laid (replace in time when discoloration occurs). The cabinet door cooling fan needs to run 24 hours a day, and the fan filter should be cleaned of dust every 3 days (accumulation thickness ≤1mm).
• Line inspection: Focus on checking whether the motor terminals and contactor contacts are carbonized due to high temperature (black color needs to be replaced). If the cable insulation layer is cracked or softened, it needs to be wrapped or replaced immediately to avoid short circuit failure.
2. Motor and sensor protection
• Motor heat dissipation: The housing temperature of the main motor should be ≤75℃. In summer, an axial flow fan (air volume ≥300m³/h) can be installed at the tail of the motor. Use compressed air to blow away the dust on the motor heat sink every two weeks (must be cleaned when the accumulation thickness is >2mm).
• Sensor calibration: Pressure sensors and temperature sensors are prone to drift at high temperatures. They should be calibrated monthly with standard instruments (e.g. pressure sensor error ≤1% FS) to avoid inaccurate feed quantity and temperature control due to signal deviation.

The above are the summer maintenance precautions and methods for the maintenance of the mechanical transmission system of the twin-screw fish feed production line, the optimization of the heating and cooling systems, and the protection of the electrical and control systems. There are other aspects of the maintenance of the fish feed production line in summer, please see the next article.