Three-quarter underside view of the blower filter unit showing the blue blower cover, round collar and perforated outlet

FFU and Terminal Air Purification Equipment

Blower Filter Unit (BFU)

A ceiling supply assembly combining a centrifugal blower, a duct-entry housing and a downstream particulate filter in one module.

Integrated Blower and Filter
Duct-Entry Housing
Perforated Outlet Guard
Ceiling Supply Configuration

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Product Introduction

This blower filter unit combines an upper blower compartment with a lower final-filter section in a coated metal enclosure. A round collar provides the duct-entry interface, while the rectangular outlet guard covers the discharge face. The cabinet includes an upper access cover and a removable lower panel for the respective service areas. It is intended as a powered cleanroom supply terminal selected together with the air system it connects to.

Key Features

The local blower places an active air-moving component at the supply terminal.

A defined duct-entry interface makes the upstream connection part of the module specification.

The upper fan chamber and lower filter section provide distinct component locations.

The lower outlet guard can be opened without using the upper access cover.

Solutions for Your Application

A powered terminal needs to be selected as part of the connected air circuit, not from the blower name alone.

Required supply volume changes when duct resistance is added.Match the blower curve to the installed duct and filter losses instead of using a free-air volume as the delivered duty.

Central supply pressure varies while the terminal fan is running.Choose a balancing and control arrangement that accounts for both fans across the intended operating range.

Filter replacement and motor repair need different access space.Plan both removal routes before selecting the terminal position and ceiling opening.

Two quotations use BFU and FFU for apparently similar equipment.Compare the actual housing, inlet, fan curve, filter seal and service arrangement rather than assuming the abbreviations define different performance levels.

Typical Applications

Duct-connected cleanroom supply pointsElectronics packaging areasClean assembly roomsCeiling supply in enclosed production zonesEngineered clean-booth air systems

Technical Parameters

Common reference construction and component options for a duct-connected blower-filter terminal.

Assembly Arrangement	Upper centrifugal-blower section feeding a lower particulate-filter section
Reference Terminal-Module Formats	Nominal 24 × 24, 24 × 36 or 24 × 48 in families, approximately 610 × 610, 610 × 915 or 610 × 1220 mm
Housing Material Options	Coated-steel cabinet or 304 stainless steel, with a perforated lower outlet guard
Duct Inlet	Round entry collar on the upper housing, with a flanged connection option
Blower Choices	Forward- or backward-curved centrifugal wheel with a matching AC or EC motor
Particulate-Filter Options	HEPA or ULPA final filter with a gasketed or gel-seal interface
Common Single-Phase Supply Options	120 V AC, 60 Hz, or 220–240 V AC, 50/60 Hz, depending on the motor version
Control Options	Local speed control; compatible EC versions with an external 0–10 V DC speed-reference input
Monitoring Accessories	Static-pressure tapping points and an optional filter-condition indicator
Service Access	Upper blower cover plus a removable lower outlet-panel and filter assembly
Customization	Available based on the intended application and operating environment.

Available Options

Duct-entry size and positionFinal-filter grade and sealing interfaceFan motor and control arrangementUpper and lower maintenance access layout

Specify the supplied build as a complete assembly. A recirculating inlet, acoustic lining, room-side motor access or a network controller requires its own configuration and is not established by the BFU designation.

Selection and Installation

Define the complete duty point

Provide the required air volume and the pressure conditions at the inlet and outlet. Compare the selected blower curve with duct, damper and final-filter resistance, including the intended filter-loading allowance. BFU is a blower-filter name, not a pressure rating; it does not by itself establish greater capacity than an FFU.

Coordinate with the upstream air system

Identify whether the inlet connects to a ducted supply or a defined recirculation path. An upstream fan and a local blower affect one another, so their operating ranges and balancing method need to work together. This terminal assembly does not replace the central system's heating, cooling or humidity-control duties.

Specify two distinct maintenance routes

Plan access to the blower, motor and electrical components separately from final-filter removal. Check ceiling depth, opening size, support points, lifting route and the clearance needed to lower the filter assembly. Room-side filter access does not automatically mean that the motor can be serviced from the room.

Compare construction, not abbreviations

State the filter grade and seal, inlet interface, sound and power requirements, control function and replacement method in the equipment schedule. For a conventional grid-mounted comparison, see the standard fan filter unit. After installation, measure the air delivered to the room and check the filter seal; the BFU label alone does not guarantee a cleanliness class or a unidirectional working zone.

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