In the fertilizer production field, automatic packaging machines play a crucial role in metering and filling qualified fertilizer products, after granulation, drying, cooling, and sieving, according to standard weights.
Equipment Structure
The automatic packaging machine adopts a modular integrated design, and the whole machine is mainly composed of the following core components:
(I) Material Storage and Feeding System: This includes a storage silo and a feeding device. The storage silo is used to temporarily store materials to be packaged and is usually equipped with a level sensor to monitor the material level. The feeding device is the key component for controlling metering accuracy—various feeding methods such as double spiral, double vibration, and double valve can be selected according to the material characteristics to achieve fast and slow two-stage feeding. Fast feeding is used first to improve efficiency, and slow, precise feeding is switched when the target value is approached to ensure accuracy.
(II) Weighing and Metering System: This is the core accuracy-ensuring component of the equipment, consisting of a high-precision weighing sensor, a weighing hopper, a weighing control instrument, and a PLC control system. The sensor uses imported high-precision components (such as Toledo weighing sensors from the USA), ensuring stable signal transmission. Depending on the machine model, two weighing methods can be used: net weight method (materials are weighed in the weighing hopper before being filled into the bag) or gross weight method (materials are directly fed into the packaging bag and measured by the sensor). (III) Bag Clamping and Filling System: Includes a pneumatic bag clamp and a hopper. The packaging bag is manually placed over the hopper, and the pneumatic bag clamp automatically clamps the bag opening, ensuring a good seal and adaptable to various bag sizes. The hopper is rationally designed to ensure smooth material flow into the packaging bag.
(IV) Conveying and Sealing System: Includes a belt conveyor and a sealing device. After filling, the packaging bag is conveyed to the sealing station. Depending on the bag material, a sewing machine or a heat sealing machine can be used for sealing.
(V) Electrical Control System: Employs a PLC programmable controller as its core, equipped with a touch-screen human-machine interface. The system can store multiple formula parameters, enabling rapid switching between different product specifications. It features over-tolerance alarms, automatic error correction, automatic zeroing, and anti-interference functions.
Application range of equipment
Automatic packaging machines have a wide range of applications. In fertilizer production, they are suitable for quantitative packaging of various fertilizers such as compound fertilizers, blended fertilizers, BB fertilizers, organic fertilizers, urea, potash fertilizers, and phosphate fertilizers. In the chemical industry, they are suitable for packaging chemical raw materials, additives, and pesticide powders. In the food industry, they are suitable for packaging rice, beans, milk powder, and condiments. In the feed industry, they are suitable for packaging feed and feed additives. In other fields, they are suitable for packaging materials such as metal powders and plastic granules. The equipment can be adapted to various packaging specifications from 5-50kg, meeting the diverse needs of small and medium-sized production enterprises to large production bases.
Types of available raw materials
Automatic packaging machines can handle a wide variety of raw materials. Granular materials include: compound fertilizer granules, urea granules, BB fertilizer granules, potash fertilizer granules, phosphate fertilizer granules, plastic granules, rice, beans, etc. Powdered materials include: organic fertilizer powder, phosphate powder, water-soluble fertilizer powder, milk powder, feed powder, metal powder, pesticide powder, etc. By changing the feeding method (double screw, double vibration, double valve, etc.), the equipment can adapt to the packaging needs of materials ranging from ultrafine powder to large particles.
Working principle of the equipment
The automatic packaging machine operates on the principle of a collaborative mechanism between electronic weighing and PLC automatic control. Its workflow can be divided into the following stages:
(I) Feeding Stage: Material is conveyed from the storage silo to the feeding port via a feeding device. A two-stage feeding method is adopted—fast feeding first to shorten the packaging cycle, and then switching to slow, precise feeding when approaching the target value to ensure accuracy. Sensors provide real-time feedback signals to control the start and stop of the feeding mechanism.
(II) Weighing Stage: Material enters the weighing hopper (or directly into the packaging bag), and the weighing sensor monitors the weight change in real time. The sensor signal is processed by the weighing control instrument and transmitted to the PLC controller. When the set weight is reached, the PLC issues a stop feeding signal.
(III) Filling and Conveying Stage: After weighing, the material is filled into the packaging bag via the discharge hopper. The bag clamping mechanism keeps the bag opening tightly clamped during the filling process. After filling, the packaging bag is conveyed to the sealing station via a conveying device.
(IV) Sealing Stage: Depending on the material of the packaging bag, a sewing machine is used for sewing and sealing, or a heat sealing machine is used for heat sealing. After sealing, the finished packaging bags are conveyed to the palletizing area via a conveyor device.
Equipment operation method
(I) Pre-start Preparation: Operators should undergo professional training and be familiar with the equipment structure and working principle before starting work. Check for loose screws in all parts. Check if the weighing sensor is installed horizontally and the wiring is secure. Check if the air source pressure meets the standard (usually 0.4-0.6MPa). Check if the power supply voltage is stable.
(II) Parameter Setting: Set the packaging weight and allowable error range through the touch-screen human-machine interface. The system can store multiple formula parameters, enabling quick switching between different product specifications.
(III) Operation: Manually place the packaging bag onto the material inlet. The bag clamping mechanism automatically clamps the bag opening. After startup, the system automatically completes feeding, weighing, filling, bag dropping, and conveying processes. During operation, the weighing data display should be monitored in real time to ensure stability.
(IV) Shutdown Operation: First, turn off the material supply. After the hopper is emptied, turn off the main unit and disconnect the power. Maintain equipment usage and maintenance records and complete shift handover procedures.
Equipment maintenance methods
(I) Daily Maintenance: Clean residual materials and dust from the equipment after each shift. Check all fastening bolts for looseness. Add an appropriate amount of grease to gears, cams, and other transmission components daily. Pay attention to waterproofing, moisture-proofing, and corrosion prevention of electrical components; keep the electrical control box and wiring terminals clean.
(II) Periodic Maintenance: Perform a component inspection at least monthly, checking the worm gear, worm shaft, bearings, and other moving parts for smooth rotation and wear. Regularly inspect the load cells and clean any accumulated material on their surfaces. Regularly calibrate the weighing system to ensure measurement accuracy. Check the condition of the silicone strips on the heat sealer; replace any damaged strips promptly.
(III) Electrical Maintenance: Check for loose or aged wiring terminals. Test the sensitivity of the emergency stop button and photoelectric sensors. Keep the inside of the electrical control box clean to prevent electrical malfunctions.
