AJ Manufacturing’s Criti-Clean Ultra Fan Filter Units (FFUs) are fan-powered laminar flow HEPA filter diffusers that remove airborne contaminants from the stream of air they deliver into a room.

Criti-Clean Ultra Fan Filter Units (FFUs) from AJ Mfg

Criti-Clean Ultra Fan Filter Units (FFUs)

We offer a wide range of fan-powered laminar flow HEPA filter diffusers – in a variety of sizes and configurations – including both ceiling-mounted and portable units. Each uses our proven HEPA filtration technology to remove airborne pathogens and deliver fresh, purified air to a room (or remove contaminated air in the case of our reverse flow units). Click below to learn more about each type of FFU:

Ceiling-Mounted Units

Mobile Units

Original Criti-Clean

Stainless Steel Lighted Operating Room System (SSLORS)

Operating Room Ceiling Systems

After decades of experience designing and manufacturing products for hospital operating rooms, we began offering complete, pre-engineered ceiling systems to simplify and speed the design and build process, while also providing outstanding performance. We now offer three ceiling systems to meet virtually any operating room need:

SSLORS Lighted Ceiling System

THD-1.5 Suspended Grid Ceiling System

Structural OR Ceiling System

SSEPD – Perimeter Slot Diffuser

SSEPD – Perimeter Slot Diffuser

The SSEPD Series Perimeter Slot Diffusers are specially designed to provide an air curtain for operating rooms.

FRD and FRD-Hepa

FRD – Flat Radial Pattern Diffuser

The FRD Model Flat Face Radial Pattern Diffusers have been designed to provide low aspiration at high ventilation rates, especially for clean room applications such as research laboratories, animal labs, food processing, hospital rooms and computer rooms.

FRD and FRD-Hepa

FRD HEPA – Flat Radial Pattern Diffuser with HEPA Filter

The FRD Model Flat Face Radial Pattern Diffuser with HEPA Filter has been designed to provide low aspiration at high ventilation rates, especially for clean room applications such as research laboratories, animal labs, food processing, hospital rooms and computer rooms. 

hinged radial diffuser

HRDP – Hinged Radial Diffuser

The HRDP Series Hinged Radial Pattern Diffuser has been designed to provide low aspiration and high ventilation rates especially for clean room applications such as research laboratories, animal labs, food processing, hospital rooms and computer rooms.

SS Hemispherical Diffuser

SS Hemispherical Diffuser

The SS Hemispherical Diffusers feature an adjustable pattern control technology for delivering high volumes of low velocity air in a radial pattern. Each model is constructed using adjustable blades which allow adjustment of the discharge air pattern. Two versions of this model are available: SS Hemispherical with an optional adjustable face and SS Hemispherical-PERF with a perforated center section. SS Hemispherical diffuser blades hang less that 1″ below the ceiling.

SSLF - Laminar Flow Diffuser Panel

SSLF – Laminar Flow Diffuser Panel

The SSLF Series Laminar Flow Ceiling Diffusers utilize the well-proven and time-tested concept of vertical air mass ‘laminar flow’ technology. The SSLF Series produce a non-aspirating, low-velocity, uniformly distributed downward moving ‘piston’ of conditioned air.

SSLF - Laminar Flow Diffuser Panel


SSLF-MC Medium Capacity Laminar Flow Diffuser Panel

The SSLF Series Medium Capacity Laminar Flow Ceiling Diffusers utilize the well-proven and time-tested concept of vertical air mass ‘laminar flow’ technology. The SSLF Series produce a non-aspirating, low-velocity, uniformly distributed downward moving ‘piston’ of conditioned air.

SSLF-HC Series High Capacity Laminar Flow Ceiling Diffuser


SSLF-HC High Capacity Laminar Flow Diffuser Panel

The SSLF-HC Series High Capacity Laminar Flow Ceiling Diffusers utilize the well-proven and time-tested concept of vertical air mass ‘laminar flow’ technology. The SSLF Series produce a non-aspirating, low-velocity, uniformly distributed downward moving ‘piston’ of conditioned air.

SSLFHFD - Laminar Flow HEPA Diffuser


SSLFHFD – Laminar Flow HEPA Diffuser

The SSLFHFD Series Laminar Flow HEPA Filter Diffuser utilizes the well-proven and time-tested concept of vertical air mass ‘laminar flow’ technology. The SSLFHFD Series produces a non-aspirating, low velocity, uniformly distributed downward moving ‘piston’ of conditioned air. The filters are designed to accommodate a Gel Seal HEPA or ULPA filter, which can be easily removed and replaced from the face of the unit.

SSLFHFD-MC Medium Capacity Laminar Flow HEPA Diffuser


SSLFHFD-MC Medium Capacity Laminar Flow HEPA Diffuser

The SSLFHFD MC Series Medium Capacity Laminar Flow HEPA Filter Diffuser utilizes the well-proven and time-tested concept of vertical air mass ‘laminar flow’ technology. The SSLFHFD Series produces a non-aspirating, low velocity, uniformly distributed downward moving ‘piston’ of conditioned air. The filters are designed to accommodate a Gel Seal HEPA or ULPA filter, which can be easily removed and replaced from the face of the unit.

SSLFHFD - Laminar Flow HEPA Filter Diffuser with LED


SSLFHFD – Laminar Flow HEPA Filter Diffuser with LED

The SSLFHFD Series Laminar Flow HEPA Filter Diffuser with LED utilizes the well-proven and time-tested concept of vertical air mass ‘laminar flow’ technology, with the addition of an LED Alert Light which, when lit, indicates a change of filter is necessary for optimal performance. The SSLFHFD Series produces a non-aspirating, low velocity, uniformly distributed downward moving ‘piston’ of conditioned air. anodized aluminum gel seal frame.

HEPA & ULPA Filters


HEPA & ULPA Filters

A-J Manufacturing provides the highest quality HEPA and ULPA Filters currently available as options in our stainless steel laminar flow and radial flow diffusers, or any combination grille, plaster frame, and plenum models in hinged or non-hinged models. Typical applications include hospitals, semiconductor manufacturing, disk drive and compact disk manufacturing, food processing, pharmaceutical production and aerospace manufacturing.

HRDP – Hinged Radial Diffuser with Filter



HRDP – Hinged Radial Diffuser with Filter

The HRDP Series Hinged Radial Pattern Diffuser with Filter is similar to the standard model, however, it incorporates an extended plenum and a unique frame designed to accommodate a Gel Seal HEPA or ULPA filter. These high quality filters can be easily removed and replaced from the face of the unit, and incorporate a separatorless 2″ deep media, integral test port and an anodized aluminum gel seal frame.

SSLFHFD FFU RF - Fan Powered Laminar Flow HEPA Filter Diffuser - Reverse Flow



SSLFHFD FFU RF – Fan Powered Laminar Flow HEPA Filter Diffuser – Reverse Flow

Reverse flow fan powered filter for filtration of exhaust. Common applications are workspaces involved with hazardous materials where exhausted air may cause a health or environmental threat. Common in medical facilities with potential airborne pathogens and used in facilities testing, packaging, and preparing fine powders that can create airborne health hazards.

SSLFHFD-T-HC High Capacity Laminar Flow HEPA Diffuser



SSLFHFD-T-HC High Capacity Laminar Flow HEPA Diffuser

SSLFHFD-T-HC High Capacity Laminar Flow HEPA Diffuser

SSLF 2 Chamber Laminar Flow Diffuser



SSLF 2 Chamber Laminar Flow Diffuser

SSLF-N-2 Chamber Laminar Flow Diffuser

Louvered Face HEPA Diffuser


Louvered Face HEPA Diffuser

Louvered Face HEPA Diffuser