The scorching summer heat has quietly faded, and the cool autumn air has arrived as expected. The crops in the fields are a vibrant golden hue, a symbol of abundant harvest joy. All signs indicate that the autumn harvest is about to begin. For large farms, rigorous inspection and maintenance of grain storage equipment is crucial before the harvest begins, especially for grain steel silo. Today, we will explain the pre-storage inspections for autumn grain in large-scale steel silos.
As core facilities for the centralized storage of autumn grain (such as corn, rice, and soybeans), pre-storage inspections are directly related to grain safety, loss reduction, and subsequent management efficiency. Autumn grain exhibits significant moisture fluctuations, is prone to heat generation due to moisture absorption, and exhibits unstable impurity levels. Therefore, a comprehensive pre-storage inspection is essential to eliminate potential storage hazards and optimize the storage environment, laying the foundation for safe storage. The following details key pre-storage inspections for autumn grain, focusing on five key aspects: silo structure, internal environment, equipment systems, safety features, and auxiliary preparations.
1. Silo Structural Integrity Inspection
The silo is the "container" for stored grain. Its structural stability directly determines its safety, so it is crucial to inspect for potential hazards such as rust, deformation, and leakage.
1.1. Silo Wall Inspection
- Rust Inspection: Use a visual inspection or a thickness gauge to inspect the silo wall steel plate surface, focusing on welds, corners, the area within 3 meters of the bottom, and areas exposed to rain for signs of rust, rust pits, or paint loss. If the rust depth exceeds 10% of the steel plate thickness, promptly remove the rust and perform repair welding (using an epoxy zinc-rich primer and topcoat for corrosion protection) to prevent deformation caused by weakened silo wall strength.
- Deformation and Weld Inspection: Observe the silo wall for localized protrusions, depressions, or vertical deviations (a laser line projector can be used). Use a magnifying glass or flaw detector to inspect welds for defects such as cracks, pores, and incomplete penetration, especially at the welds connecting the silo wall to the roof and floor. If cracks are found, immediately stop the machine, perform repair welding, and perform a strength test.
- Sealing Performance Check: After closing all doors and vents, perform a "smoke test" (ignite a smoke bomb to observe whether smoke escapes from the outside) or a water pressure test (pour water on suspected leaks to observe whether water seeps from the inside) to check for holes or gaps in the warehouse walls to prevent rainwater from seeping in or moisture from escaping.
1.2. Roof Inspection
- Rainproofing and Load-Bearing Inspection: Clean the roof of the warehouse of debris (such as fallen leaves and dust), inspect the rainproofing layer (color-coated steel plate, waterproofing layer) for damage or cracks, and check whether the gutters are blocked (drains should be cleared to ensure smooth drainage of rainwater). Test the load-bearing capacity of the warehouse roof (especially for older warehouses). Perform a load test or structural review to confirm whether it meets the operational requirements of maintenance personnel and equipment (such as ventilators).
- Ventilation and Safety Inspection: Check the silo roof vent cap for unobstructed access (check for clogged or deformed insect screens) to ensure proper air exchange within the grain pile. Verify the integrity of the silo roof guardrail (height ≥ 1.2 meters), ladder (non-slip steps, secure handrails), and work platform (non-slip coating) to prevent falls.
1.3. Silo Floor Inspection
- Floor and Support Structure Inspection: Enter the silo (pre-ventilate and check for oxygen concentration ≥ 19.5%) and inspect the silo floor steel plate for deformation and corrosion (especially where it contacts the ground). Check the verticality and rust of the support columns, and the firm connection to the ground (no looseness or cracks).
- Grain Unloading and Clearance Inspection: Check the manual/electric unloading gate for proper opening and closing, and the seals for aging (replace if loose). Check the clearance cover for integrity and tightness when closed to prevent grain leakage and pest intrusion.
2. Cleaning and Disinfection of the Silo Environment
Before storing autumn grain, thoroughly remove any remaining impurities, insects, mildew, and odors to create a clean and sterile storage environment and prevent contamination or cross-contamination of the new grain.
1. Thorough Silo Cleaning
- Removing Residual Grain and Impurities: Use manual cleaning (with a negative pressure vacuum cleaner) and a mechanical bin cleaner (for large silos). Focus on removing residual grain, dust, weeds, and other impurities from the corners of the silo floor, gaps in ventilation ducts, and clinging to the walls. Ensure there are no visible residues. (This can be verified using the "white light inspection method": shine a strong flashlight inside the silo to ensure no visible particles or fibers.)
- Equipment Surface Cleaning: Wipe or rinse fixed equipment in the silo (such as ventilation ducts, temperature measurement cables, and grain retaining plates) to remove surface oil and grain dust to prevent impurities from mixing with the new grain and breeding microorganisms.
2. Disinfection and Pest Control
- Environmental Disinfection: Physical disinfection is preferred (e.g., ultraviolet light irradiation for 2-3 hours per session, covering all areas of the silo). If chemical disinfection is required, low-toxic agents (e.g., 2% sodium hypochlorite solution, 0.5% peracetic acid) can be sprayed on the silo walls, floor, and equipment surfaces, focusing on areas prone to insect and mildew breeding, such as corners and crevices. After disinfection, ventilate the area for at least 48 hours to ensure that the residual agent meets food safety standards (residue ≤ 0.1 mg/kg).
- Pre-treatment for Pest Control: For silos with a history of insect infestation, insect-proof netting (pore size ≤ 1 mm) can be laid on the silo floor and ventilation ducts, or non-toxic insect bait (e.g., diatomaceous earth) can be placed in the corners of the silo walls to prevent the initial infestation of stored grain pests (such as corn weevils and rice weevils).
3. Functional Inspection of Supporting Equipment Systems
Silo conveying, ventilation, and temperature measurement equipment are the lifeline for the storage and delivery of autumn grain. Stable operation and performance standards must be ensured.
3.1. Conveying Equipment Inspection
- Warehouse conveying system: including elevators, belt conveyors, scraper conveyors, etc., need to be checked item by item:
- Motors and transmission components: Test whether the motor operates smoothly under no-load conditions (no abnormal noise or overheating), whether the reducer lubricating oil level is normal (no emulsification or impurities), check chain and belt tension (belt deviation ≤ 50mm), wear (chain pitch elongation ≤ 3%, belt cracks), and whether transmission gears mesh evenly.
- Feeding and unloading devices: Check whether the feed hopper is clogged or deformed, whether the discharge chute is unobstructed (no residual impurities), and whether the gates open and close freely (electric gates require testing in both remote and manual modes).
- Safety protection: Verify whether the equipment's overload protection (such as the motor thermal relay) and deviation protection (belt deviation prevention switch) are sensitive, and whether the emergency stop button is functional (the equipment stops immediately when pressed).
3.2. Ventilation System Inspection
- Ventilation Equipment: Axial and centrifugal fans should be tested for 30 minutes at no load. Check operating noise (≤85dB) and vibration (≤0.1mm). Verify that the fan is rotating correctly (the air direction matches the duct markings). Clean the fan filter (if any) to ensure unobstructed air flow.
- Duct System: Check the above-ground cage/underground duct for deformation or damage (use a flashlight to shine through the duct gaps to ensure there are no leaks). Ensure the duct joints are sealed (use sealing tape to reinforce). Test ventilation uniformity (use a smoke generator to observe uniform smoke distribution at the duct outlet). Avoid dead spots that could cause heating in the grain pile.
3.3. Temperature Measurement and Monitoring System Inspection
- Electronic Temperature Measurement System: Calibrate the temperature sensor (using a standard thermometer for comparison, error ≤ ±0.5°C). Check that the sensor is inserted into the grain pile to the required depth (≥30cm from the bottom of the silo, ≤3m apart). Test the circuit continuity (using a multimeter to check resistance and ensure there are no short circuits or open circuits). Check that the main unit display is normal (no data loss or garbled characters). Ensure real-time monitoring of grain pile temperature changes.
- Video Monitoring and Alarms: Check that the camera images in the silo are clear (covering key areas such as the grain surface and silo doors). Verify that the main unit storage function is functioning properly. Verify that the grain condition alarm system (high temperature and smoke alarms) is sensitive (simulate high temperature signals, alarm response time ≤10 seconds).
4. Safety Facility Compliance Inspection
Autumn grain storage involves mechanical operations and high-altitude operations. Safety facility inspections are required to eliminate risks to personnel and equipment.
4.1. Firefighting and Explosion-Proof Facilities
- Check the number of fire extinguishers (dry powder/CO2 type) in the warehouse area (at least one set per 50 square meters), their pressure values (indicators in the green zone), whether the water pressure on fire hydrants meets the standard (water outlet pressure ≥ 0.2 MPa), and whether the fire hoses are intact and the connectors are properly connected.
- If storing high-dust grains (such as wheat), check that explosion-proof lighting and switches are intact, and that the ventilation system and dust removal equipment are properly connected (to prevent explosions caused by excessive dust concentration).
4.2. Electrical and Grounding Safety
- Check electrical wiring (cables, distribution boxes) in and around the warehouse for aging and exposed areas (use conduit protection), and that joints are secure (no signs of looseness or overheating). Test the grounding resistance of the equipment (≤ 4Ω) to ensure that it can be quickly discharged to ground in the event of a leakage.
- Perform insulation tests on the power cords and plugs of mobile equipment (such as forklifts and conveyors) (insulation resistance ≥ 0.5MΩ) to prevent leakage during rainy days.
4.3. Protective and Emergency Facilities
- Roof ladders and work platforms must be equipped with anti-slip strips (groove depth ≥ 3mm), and guardrails must be equipped with anti-fall footboards (height ≥ 18cm). Warning signs such as "Do Not Enter" and "Wear Safety Belt" should be posted on warehouse doors.
- Equip emergency supplies: first aid kit (including tourniquets and disinfectants), emergency lighting (lasting ≥ 4 hours), and gas masks (for fumigants such as aluminum phosphide). Ensure that workers are aware of their storage locations and instructions.
5. Auxiliary Preparations
In addition to hardware inspections, advance planning and preparation are necessary to improve storage efficiency and reduce grain storage risks.
5.1. Grain Storage Plan and Storage Space Planning
- Determine storage space allocation based on autumn grain type (corn, rice, etc.), quantity, and storage period (e.g., high-moisture grain should be prioritized in well-ventilated storage). Establish a storage order (to avoid mixing different grain types).
- Calculate the maximum grain storage capacity of a single silo (based on the silo's design load, allowing for a clearance of ≥0.5m between the grain surface and the silo roof) to avoid deformation caused by overstorage.
5.2. Grain Quality Testing and Tool Calibration
- Prepare grain quality testing tools: moisture meter (calibration error ≤±0.5%), bulk density gauge, impurity screen, etc., to ensure rapid testing of autumn grain moisture (safety moisture for corn ≤14%, rice ≤13%), impurities (≤1%), and other indicators before storage. Unqualified grain must be cleaned/aired before storage.
5.3. Personnel Training and Process Drills
- Conduct training for warehouse operators: Focus on equipment operating procedures (e.g., requiring an empty-load test run before starting the elevator), safety precautions (wearing a safety belt when working at height, and avoiding touching machinery while it is operating), and autumn grain storage characteristics (e.g., corn tends to clump after absorbing moisture, requiring moisture control upon entry).
- Conduct warehouse process drills (e.g., coordinated conveyor equipment and emergency shutdowns) to ensure smooth coordination and minimize operational errors.
Summary
Pre-storage inspections of grain steel silo for autumn grain should adhere to the principles of "no structural hazards, no environmental pollution, no equipment failures, and no safety blind spots." This involves comprehensive inspections of the silo structure, environment, equipment, safety, and auxiliary equipment to eliminate potential risks. After the inspection is complete, a "Checklist of Inspections and Corrective Actions" should be compiled. Any issues found (such as silo wall corrosion and abnormal fan noise) must be rectified within a specified timeframe and re-inspected. Once all items meet the required standards, autumn grain storage can begin. This lays a solid foundation for subsequent safe grain storage (e.g., ventilation and cooling, and grain condition monitoring).
The above summarizes the pre-storage inspections for autumn grain in large steel silos. I hope this explanation will be helpful for future operations of large steel silos.
Written by
Shandong Shelley Grain Steel Silo Co., Ltd
Editor Jin
WhatsApp : +86-18653877118
Email : shelley@cnshelley.com
