Air Filters and Chemical Filtration

Rigid Box Air Filter

A rigid deep-pleat filter that packages a large glass-fiber media area inside a gasketed galvanized box for stable operation under variable airflow.

Rigid Box Construction
Deep-Pleat Media Pack
Stable Variable-Airflow Service
Gasketed Header Seal

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Product Introduction

The rigid box air filter encloses a medium-efficiency deep-pleated glass-fiber pack inside a galvanized steel frame with a single header or box flange. Aluminum or hot-melt separators hold adjacent pleats apart so airflow reaches the full media depth. Polyurethane sealant fixes the pack to the frame and closes the perimeter against bypass, while a neoprene or polyurethane gasket seals the header to the filter bank. The rigid construction remains stable in air handlers where flexible pockets may move or collapse during rapid airflow changes.

Key Features

Deep pleats place a large media area inside a compact rigid box envelope.

Separators preserve uniform channels and stop adjacent pleat faces from touching.

A galvanized frame resists distortion during front loading and variable-air-volume operation.

Perimeter sealant and a replaceable header gasket create two distinct barriers against bypass.

Customer Product Concerns

A rigid box filter must keep its media channels open and seal both the internal pack and the external mounting interface.

Flexible filters collapse or flap when airflow changes rapidly.A fixed box frame and supported pleat pack maintain geometry across the operating range.

Deep pleats touch and block airflow through the center of the media pack.Aluminum or hot-melt separators create consistent channels from the upstream to downstream face.

Air bypasses between the pleated pack and the inside wall of the box.Continuous polyurethane sealant bonds the pack perimeter to the galvanized frame.

The filter header leaks against an uneven bank frame after repeated changes.A resilient replaceable gasket compresses around the entire mounting flange.

Typical Applications

Built-up air-handler filter banksCleanroom preparatory filtrationHospital and pharmaceutical HVACVariable-air-volume systemsPrefiltration before terminal HEPA stages

Technical Parameters

Typical construction ranges for a rigid medium-efficiency deep-pleat box air filter are listed below.

Core Material	Deep-pleated microglass media with aluminum or hot-melt separators
Panel Thickness	150 or 292 mm nominal box depth
Effective Width	305-610 mm modular face width
Maximum Length	Up to 610 mm modular face length
Steel Facing Thickness	0.70-1.00 mm galvanized box frame and header flange
Core Density	Approximately 60-110 kg/m³ nominal assembled media-pack density
Thermal Conductivity	Approximately 0.035-0.045 W/(m·K) for the dry microglass media
Surface Finish	Mill-galvanized steel box with white media and aluminum or polymer separators
Joint Type	Pleated pack polyurethane-sealed into a rigid box with single-header or gasketed flange connection
Customization	Available based on the intended application and operating environment.

Available Options

MERV 11 to MERV 15 grades150 mm or 292 mm depthAluminum- or hot-melt-separated mediaSingle header, double header or box-style frame

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