Wet grinding suppresses part of the dry dust at the tool, but it can generate a fine liquid aerosol containing coolant, water, metal particles and process residues. These droplets can escape the machine or workstation, deposit on surfaces and load unsuitable filters.
How wet-grinding aerosol forms
Tool speed, impact, atomisation of the grinding fluid, evaporation and air movement inside the machine break liquid into small droplets. The smallest droplets remain suspended and travel with the exhaust air. Splash and larger drops require containment and drainage, while the aerosol fraction requires separation from the airflow.
Why control is necessary
- airborne mist can enter the operator’s breathing zone;
- oily or wet deposits can affect floors, machine surfaces and electrical enclosures;
- mist escaping into the hall can be drawn into unrelated ventilation systems;
- unstable extraction can affect visibility and the cleanliness of the process area;
- dry filters may blind rapidly when exposed to liquid aerosol.
Correct extraction principles
Capture at the enclosure
The machine or workstation is kept under slight controlled negative pressure so that aerosol does not escape when closed. The capture opening is positioned to remove mist without drawing excessive grinding fluid into the duct.
Coalescing separation
Mist separators and coalescing stages cause fine droplets to combine and drain. Pre-separation can remove larger drops and particles before the final stage. Drainage paths must remain open and compatible with the fluid.
Stable airflow
Too little airflow allows mist to escape; too much airflow can entrain excessive liquid and increase treatment load. The fan and control strategy maintain the calculated enclosure pressure throughout filter loading.
Moisture-resistant components
Ducting, seals, fan materials and access points are selected for humidity, fluid chemistry and corrosion risk. Low points are designed to avoid uncontrolled liquid accumulation.
Central or local systems
A local unit can serve one machine and simplify fluid return. A central installation can serve several machines when aerosol characteristics and operating schedules are compatible. Branch balancing and drainage become especially important in a shared network.
Design sequence
- identify the grinding fluid, particle load, temperature and duty cycle;
- define enclosure leakage and the capture connection;
- size ducting for aerosol transport and drainage;
- select droplet pre-separation, coalescing and final stages;
- choose a fan for the complete operating pressure range;
- provide monitoring for pressure, drainage and filter condition.
Maintenance priorities
Service work includes cleaning separator stages, checking drains, inspecting duct deposits and corrosion, monitoring pressure drop and fan vibration, and confirming that doors or machine openings remain under control. Service intervals follow the actual fluid and production load.
Contact ALWO with details of the wet-grinding machine, fluid and operating schedule to configure an extraction and mist-separation solution.
