Operation process of recirculation fumigation machine: standardized steps from preparation to completion

　　1.Preparation before fumigation:7 core tasks

　　1.On-site inspection:

　　Grain condition inspection:Measure the temperature of the grain pile(with points distributed in layers,3-5 points per layer),moisture content(using a rapid moisture meter,with an error of≤0.5%),and pest density(using a light trap or sampling sieve,recording the species and quantity of pests).

　　Storage parameters:Measure the volume of the storage and the height of the grain pile,and test the air tightness(pressure decay test:the time taken for the pressure to drop from 500Pa to 250Pa should be≥40 seconds).

　　2.Plan formulation:

　　Dosage calculation:Determine based on"insect species+grain bulk volume".For example,the dosage for phosphine in a grain bulk infected with weevil is 3-5g/m³.

　　Parameter settings:temperature at 25℃,humidity at 70%,fumigation duration of 96 hours,subject to seasonal adjustments(extended to 120 hours in winter).

　　3.Personnel and Protection:

　　Staffing:3-5 people(1 operator,2 inspectors,1 emergency personnel),all required to hold relevant certificates(Fumigation Operation Qualification Certificate).

　　Protective equipment:positive pressure respirator(endurance≥4 hours),chemical protective suit,rubber gloves,and toxic gas detector(range 0-100ppm).

　　4.Equipment inspection:

　　Host machine:Test the fan rotation,heating device temperature rise rate,and control system display for normal operation.

　　Pipeline:Check the tightness of the joints(no bubbles detected with soap water)and the flexibility of the valve switches.

　　Safety device:Verify the sensitivity of the toxic gas alarm and emergency shutdown functions.

　　5.Warehouse pre-treatment:

　　Cleaning grain and flour:Remove impurities and lumps to ensure smooth air flow.

　　Sealing operation:Cover the grain surface with film(single-sided sealing)or cover(five-sided/six-sided sealing),seal doors and windows with film+tape,and close and lock the ventilation openings.

　　6.Preparation of reagents:

　　Aluminium phosphide:Use immediately after unsealing to avoid moisture(operation should be carried out in a dry environment).

　　Liquid medicament:Dilute according to the specified ratio(such as a 1:9 mixture of ethylene oxide and carbon dioxide),and store in explosion-proof containers.

　　7.Emergency plan:

　　Clarify the leakage handling process(shutdown,evacuation,ventilation,neutralization),equip with a first aid kit(including antidotes such as pralidoxime chloride),and contact nearby hospitals to establish a green channel.

　　II.Fumigation operation:standardized execution in 6 steps

　　1.Equipment startup:

　　Turn on the main power,activate the control system,set the temperature,humidity,and time parameters,and preheat the main unit(for about 10 minutes).

　　Start the fan and confirm that the airflow direction is correct(forming a circulation from the dosing port to the return air inlet).

　　2.Chemical dosing:

　　Aluminium phosphide:Place the tablets into the reaction tank through the external dosing machine,add an appropriate amount of water(0.5L of water per kg of agent),close the tank door,and then open the valve to allow gas to enter the circulation system.

　　Steam fumigation:Start the heating device,and when the steam temperature reaches 121℃and the pressure reaches 0.1MPa,open the steam valve to enter the pipeline.

　　3.Concentration monitoring:

　　Initial stage(0-2 hours):Record the concentration every 30 minutes to ensure it reaches the set value(such as 0.3g/m³for phosphine)within 1 hour.

　　Stabilization phase(2-96 hours):Monitor every 6 hours.If the concentration fluctuation exceeds±10%,replenish the solution through the dosing machine.

　　4.Inspection and maintenance:

　　Conduct a patrol inspection every 2 hours to check for any leaks at pipeline joints(by placing a detector close to the joint),ensure that the equipment is operating with normal sound,and inspect the sealing of the storage body for any damage.

　　Record data:temperature,humidity,concentration,equipment status,and compile a"Fumigation Operation Log".

　　5.Exception handling:

　　Sudden decrease in concentration:Immediately shut down the machine to inspect the sealing points.After repair,reintroduce the chemicals and extend the fumigation time.

　　Equipment malfunction:Activate the standby equipment.If it cannot be repaired,initiate emergency ventilation and handle the situation after the gas is fully dispersed.

　　Personnel poisoning:Immediately evacuate to a well-ventilated area,administer an antidote,and seek medical treatment(for phosphine poisoning,inject pralidoxime chloride).

　　III.Fumigation Completion:5 Steps for Safe Closure

　　1.Stop dosing:After reaching the set time,turn off the dosing device or heating system,and continue the circulation for 30 minutes(to ensure even circulation of residual gas).

　　2.Gas emissions:

　　Open the ventilation vent of the warehouse and start the fan to exhaust the gas(phosphine needs to be discharged to an open area,away from people).

　　Monitor the concentration at the emission outlet,and only stop ventilation when it is below 0.3ppm(for about 24-48 hours).

　　3.Residue disposal:

　　Aluminium phosphide residue:Collect in a dedicated explosion-proof bucket and dispose of it through a professional organization(do not discard it casually to avoid generating toxic gas when it comes into contact with water).

　　Pipe cleaning:flush the dosing pipe with clean water and sterilize it with high-temperature steam for 30 minutes.

　　4.Effect detection:

　　Sampling inspection:Samples are taken from different parts of the grain pile(5 points per layer),and the mortality rate of pests is detected using the culture method,which needs to reach 100%.

　　Safety inspection:Use a detector to measure the gas concentration inside the warehouse.Only when the concentration is below 0.1ppm can personnel enter.

　　5.Device reset:

　　Turn off the main power supply,clean the dust on the equipment surface,drain the water accumulated in the pipeline,and apply anti-rust oil to the sealed joints.

　　Organize records:Archive the"Fumigation Operation Log"and"Concentration Monitoring Table"and keep them for at least 3 years.

　　Henan Jinming Automation Equipment Co.,Ltd.specializes in providing a range of systems and projects,including grain cooling machines,circulating fumigation machines,specialized air conditioning for grain silos,intelligent ventilation systems,grain condition monitoring systems,intelligent grain storage and retrieval systems,grain silo exhaust gas purification and treatment systems,intelligent grain sampling systems,and electromechanical integration equipment installation systems.If you have any needs,please feel free to contact us