Air Washer Filtration

HVAC air washers and humidification systems recirculate water spraying into air streams. Airborne dust, pollen, biological material, and minerals accumulate in water. Solids plug spray nozzles, foul heat exchangers, and reduce washing efficiency. Multimedia filtration maintains clean water.

Filter Configuration

Vertical pressure vessel with scrubber water return inlet distributor, anthracite layer 18-24 inches removing larger particles, sand layer 12-18 inches capturing finer solids, garnet layer 6-12 inches final polishing, gravel support bed, underdrain system.

Media Specifications

Anthracite effective size 1.0-2.0mm, sand 0.5-0.8mm, garnet 0.3-0.5mm. Graded density prevents intermixing during backwash. Total bed depth 36-54 inches. Media life 5-10 years with proper maintenance.

Operating Pressure

Typical 30-80 psig matching air washer circulation pump pressure. Clean bed pressure drop 5-10 psi increasing to 15-20 psi at cycle end triggering backwash.

Filtration Performance

Removes suspended solids to 10-20 microns. Turbidity reduction from 20-100 NTU to under 5 NTU. Efficiency depends on loading rate typically 5-8 gpm per square foot bed area.

Material Construction

Carbon steel with epoxy coating or stainless steel for recirculating water service. Materials resist corrosion from treatment chemicals and minerals. Internal distribution corrosion-resistant. External coating protects atmospheric exposure.

Backwash System

Upflow water at 15-20 gpm per square foot expands bed 30-50% washing trapped solids to drain. Backwash frequency based on pressure drop typically daily to weekly depending on air quality and water conditions.

Applications

HVAC central plant air washers, industrial humidification systems, evaporative cooling tower makeup clarification, spray chamber recirculation water, and any air washing system requiring water quality maintenance.

Nozzle Protection

Clean water prevents spray nozzle plugging maintaining uniform spray patterns. Solids accumulation reduces flow and droplet size distribution. Filtration ensures consistent air-water contact.

Heat Exchanger Protection

Air washers with cooling or heating coils require clean water preventing fouling. Suspended solids create insulating deposits reducing thermal efficiency. Filtration maintains design heat transfer rates.

Side-Stream Design

Common configuration treats portion of recirculation flow continuously. Typical 10-30% of total flow filtered. Complete water turnover every few hours maintaining overall system cleanliness.

Biological Control

Filtration removes biological material reducing biofilm formation. Combination with biocide treatment maintains clean system. Reduces chemical consumption through solids removal.

Capacity Sizing

Filter area based on scrubber water flow rate and loading rate. Balance between filter size and backwash frequency. Proper sizing ensures continuous air washer operation.

Performance Benefits

Maintains spray nozzle and heat exchanger efficiency. Improves water clarity and system appearance. Reduces maintenance from solids accumulation. Simple proven multimedia technology.

Construction Standards

Pressure vessels per ASME Section VIII. Materials for recirculating water with treatment chemicals. Backwash system per hydraulic design. Complete documentation with filtration specifications and media gradation.

ERGIL air washer return multimedia filters maintain water quality removing suspended solids in HVAC and industrial air washing applications.