Design Key Points of Explosion-Proof Vacuum Cleaning System for Feed Mills

       In the production environment of feed mills, a large amount of combustible dust (such as grain dust and protein dust) is generated during the crushing, mixing, and conveying of raw materials and finished products like grains, soybean meal, and

fish meal. If accumulated to a certain concentration and exposed to ignition sources, it can easily cause explosions. Theexplosion-proof vacuum cleaning system is a specialized cleaning equipment designed for this risk. It reduces explosion hazards 

rom the source by efficiently collecting dust and eliminating ignition sources, while also ensuring a clean production environment.

Core Functions and Design Key Points

The core of the explosion-proof vacuum cleaning system for feed mills lies in "explosion-proof" + "efficient dust suction". It must simultaneously meet the requirements of dust collection efficiency, explosion-proof safety, and industry hygiene standards. 

The specific design key points are as follows:

1. Explosion-Proof Performance: Eliminating Ignition Sources

Feed dust is a type of combustible dust (with an explosion limit usually ranging from 20-60g/m³). The system must eliminate ignition sources from three aspects: electrical, mechanical, and electrostatic:

Electrical explosion-proof: Core components (motors, switches, controllers) must comply with explosion-proof standards (such as China's Ex dⅡCT4 and EU ATEX) to prevent electric sparks from igniting dust. Cable joints must be sealed to prevent dust intrusion.

Mechanical friction prevention: Impellers and inner pipe walls should be made of wear-resistant materials (such as stainless steel) to avoid sparks generated by material friction. Rotating components (bearings) must be fully lubricated to prevent overheating.

Electrostatic protection: All equipment (host, pipelines, suction nozzles) must be reliably grounded (grounding resistance ≤4Ω). Pipelines should be made of conductive materials (such as stainless steel) to prevent electrostatic accumulation and discharge caused

by friction between dust and pipe walls.

2. Efficient Dust Suction and Filtration: Controlling Dust Concentration

The negative pressure cleaning system must quickly collect dust on equipment surfaces, floors, and corners, while avoiding dust leakage or secondary pollution:

Vacuum host: Explosion-proof vacuum pumps (such as oil-free scroll pumps and explosion-proof centrifugal fans) should be selected. Air volume (usually 500-2000m³/h) and vacuum degree (≥15kPa) are designed according to workshop area and dust amount to 

ensure sufficient suction during long-distance pipeline transportation.

Filtration system:

Multi-stage filtration (pre-filtration + main filtration) is adopted. The main filter material uses oil-resistant, high-efficiency coated polyester filter bags (filtration efficiency ≥99.9%@0.3μm), which are suitable for oily dust possibly contained in feed (such as fish 

meal and meat and bone meal).

An automatic dust cleaning device (such as pulse backblowing) is equipped to regularly clean dust attached to the surface of filter bags, avoiding reduced suction or excessive pressure caused by blockage.

Pipelines and suction nozzles: Pipelines are made of 304 stainless steel (smooth inner walls reduce dust adhesion). Branch pipelines are designed according to workshop layout (covering dust-prone areas such as mixers, elevators, and silos). Suction nozzles are 

explosion-proof (such as anti-static plastic or stainless steel) to adapt to different scenarios such as floors and equipment gaps.

3. Safety Monitoring and Emergency Protection

Overload protection: Motors are equipped with overheating and overcurrent protection devices, which automatically shut down when equipment is abnormal.

Pressure monitoring: Pressure sensors are installed before and after the filtration system. When the pressure difference is too large due to filter bag blockage, an alarm is triggered to prompt dust cleaning.

Dust collection tank: It adopts an explosion-proof design (such as an explosion-resistant container), with a capacity matching the dust suction amount. Anti-static and anti-dust emission measures are required during unloading (such as equipping a closeddischarge valve).

4. Compliance with Feed Industry Hygiene Requirements

Components in contact with dust (pipelines, filter bags, collection tanks) should be made of food-grade stainless steel (304/316) with smooth surfaces for easy cleaning, to avoid bacterial growth due to residual dust.

The system must be easy to disassemble and clean, with regular disinfection, complying with feed production hygiene standards (such as GB 13078 Feed Hygiene Standard).

Typical Application Scenarios

Scattered dust on the ground and platforms of feed workshops;

Residual dust on the surfaces and interiors of equipment such as mixers, crushers, and pellet mills;

Accumulated dust on the inner walls of conveying pipelines and silos;

Finished product dust in packaging workshops (such as fine powder generated by crushing granular materials).

Maintenance Points

1. Regularly check the integrity of explosion-proof components (such as sealing rings and junction boxes) to ensure the explosion-proof grade remains effective;

2. Clean the filtration system weekly and replace filter bags monthly (adjust according to dust amount);

3. Check the grounding system daily to ensure normal electrostatic discharge;

4. Collected dust must be transported to designated areas in a closed manner (such as reuse in production or safe disposal) to avoid secondary accumulation.

        Through the above design, the explosion-proof vacuum cleaning system can effectively control the dust concentration in feed mills (＜50% of the lower explosion limit), reduce explosion risks from the source, and ensure a clean production environmentcomplying with safety production and hygiene standards.