Fluent Conveyors - The leading conveyor manufacturer

Conveyor air knives

Fluent supplies blower-driven and compressed-air conveyor air knives for non-contact belt cleaning, blow-off, and drying. Units fit Fluent-built conveyors and retrofit to existing lines from other manufacturers. Coverage is available for belt widths from 12"–96", with aluminum and stainless-steel constructions including 304 and 316 options.

Blower-driven air knives

Air knife types we supply

Blower-driven air knives

High-volume, low-pressure systems. A dedicated centrifugal or regenerative blower feeds a plenum that produces a continuous sheet of air. These systems suit wide belts, continuous duty, and plants without spare compressed-air capacity. Coverage can extend beyond 96" with longer or multiple air knives.

We supply complete air knife units and the support components needed to keep them operating.

Air knife applications

An air knife uses a pressurized plenum and a continuous or engineered slot to produce a controlled sheet of high-velocity air across a belt or the product moving on it.

Return-side belt cleaning: removing fine, dry, loose carryback after the belt leaves the discharge pulley.

Dewatering: driving surface water off the belt or product after a wash stage.

Blow-off: clearing chips, coolant, dust, and loose debris from parts on the carrying run.

Drying: removing residual surface moisture before labeling, scanning, packaging, or freezing.

Specifications

The ranges below represent commercial systems across multiple manufacturers. Exact performance depends on air source, discharge geometry, operating pressure, knife length, standoff distance, and application.

Blower-driven air knives

Compressed-air air knives

Blast nozzle bars

Typical use

Wide belts, continuous duty, drying, dewatering, and broad uniform blow-off

Narrower belts, intermittent duty, tight mounting spaces, and targeted blow-off

Concentrated cleaning of cleats, seams, pockets, and stubborn debris

Coverage width

12"–96"; wider custom or multi-knife arrangements available

Approximately 3"–108" in some aluminum and stainless product families; multiple knives can cover wider spans

Sized by nozzle count, spacing, and manifold length

Supply source

Dedicated centrifugal or regenerative blower

Plant compressed air

Plant compressed air or dedicated compressed-air supply

Supply pressure

Roughly 0.4–4.5 psig; specialty designs vary

20–100 psig, with 40–80 psig a common operating range

Application-dependent

Exit velocity

Roughly 15,000–40,000 fpm

Design-dependent; high local velocity at the discharge slot

High-velocity discrete jets concentrated at individual nozzles

Air consumption

Determined by blower airflow, knife length, pressure, and gap

Roughly 1.1–4.1 scfm per inch across 20–100 psig on representative 0.002" slot designs; approximately 2.9–3.4 scfm per inch at 80 psig

Determined by nozzle type, orifice, quantity, and supply pressure

Power requirement

Approximately 3–20 HP is common for packaged systems, with larger and smaller systems available

Supplied by the plant compressor; electrical load occurs at the compressor rather than the knife

Supplied by the plant compressor; demand increases with nozzle count and pressure

Duty cycle

Continuous

Best where adequate compressor capacity exists

Targeted or intermittent cleaning unless plant air capacity supports continuous use

Body materials

Aluminum, 304 stainless, 316 stainless, and other application-specific constructions

Aluminum, 303 stainless, 316 stainless, PVDF, and other application-specific constructions

Aluminum, stainless steel, engineered polymers, and other materials depending on nozzle and manifold design

Primary limitation

Requires blower, ducting, electrical service, and more installation space

Can consume substantial compressed-air capacity on long or continuously operating systems

Less uniform coverage between jets than a continuous-slot air knife

Built for effective material removal
and cleaner belt operation.

Air knives versus scrapers and brushes

Air knives and belt scrapers serve different cleaning conditions. In most heavy bulk applications, a mechanical cleaner performs the primary cleaning. Conventional primary cleaners typically remove roughly 50–70% of initial carryback, while a primary and secondary system can exceed 90%. An air knife does not apply the same direct mechanical scraping force. On wet, sticky, high-tonnage material, using one as the sole primary cleaner is unlikely to match a properly selected mechanical cleaning system.

Air knives clean products or the belt without belt contact. Choose an air knife over a belt scraper when:

A worn or gouged cover prevents a scraper blade from seating evenly.
The belt has a chevron, cleated, or sidewall profile.
Chemically aggressive materials would degrade the scraper blade prematurely.
You require sanitary non-contact processes like food handling.

Fluent Conveyors | Leadership in Industrial Conveyors Background

Mounting positions

Return-side mounting

The knife sits beneath the return run downstream of the discharge pulley and is typically angled against belt travel, so removed material moves toward a controlled collection point. This is a common position for carryback removal. Clearance between the belt and the return idlers sets the available mounting envelope. If the belt flutters enough to change standoff distance, a stabilizing roller or other belt support can be added opposite the knife.

Head pulley and discharge mounting

Mounting close to the head pulley keeps removed material close to the normal discharge and can simplify collection. The tradeoff is limited space. Chute walls, primary scraper hardware, and pulley guarding often compete for the same mounting envelope, and adjustment access may be poor. Measure clearance in both axes before selecting this position.

Product-side mounting

For drying and blow-off, the knife mounts above the carrying run and aims at the product. Opposed upper and lower knives reach both sides of products traveling on open surfaces such as wire mesh or perforated belting. Side knives can also remove water that a top-mounted knife pushes toward the edges without clearing.

Retrofit considerations

Retrofitting an air knife to an existing conveyor requires a mounting surface, a route for air or electrical service, and access for angle adjustment. Frame members may need a bolt-on mounting plate. On belts running mechanical splices, non-contact cleaning avoids the repeated blade deflection caused by raised fasteners.

How to capture removed materials

An air knife moves material off the belt but does not contain it. Carryback blown from a return run can become airborne or fall to the floor unless the discharge zone is controlled. With fine dry material, an uncontained airstream can increase airborne dust around the conveyor. A hood or shroud around the cleaning zone, connected to the plant dust collection system where appropriate, should be considered part of the installation. Conveyor skirting at the collection point can help keep captured material contained until it returns to the material stream.

Wet blow-off requires similar containment with different hardware. A splash enclosure, drip tray, and drain connection handle the water and slurry removed during dewatering. When the knife sits near a transfer point, a collection chute can return material to the main stream ahead of the impact bed rather than dropping it beneath the conveyor. Enclosed installations also need enough airflow and ventilation capacity to handle the volume of air being introduced.

Industries and applications

Air knives serve a narrow range of belt-cleaning applications. They are strongest on fine dry material, surface water, loose debris, and lines where continuous contact with the belt or product is undesirable. The applications below account for much of the conveyor air knife work we quote.

Aggregate wash plants

Removes surface water and loose residual fines from belts or washed product, reducing moisture carried downstream

Plastics recycling

Dewaters flake and film after washing and clears loose fines from transfer belts ahead of extrusion

Sorting lines

Keeps belt surfaces cleaner around optical and sensor equipment where accumulated fines can interfere with detection

Manufacturing

Blows chips, swarf, coolant, dust, and loose debris from parts and conveyor surfaces

Package Handling

Removes surface moisture and dust before labeling, scanning, and palletizing

Foundries

Provides non-contact cleaning where abrasive sand and fines can accelerate wear on contact components

Maintenance and troubleshooting

Air knife maintenance focuses on air quality, the discharge slot or nozzles, alignment, and the air source. Blower intakes, drive belts where used, duct joints, regulators, and compressed-air filtration should be included in routine inspections.

Problem

Likely cause

First step

Clean and dirty bands across the belt width

Partial slot blockage, nozzle obstruction, or damaged shim

Isolate the air supply, clean the discharge according to the manufacturer's procedure, and inspect the shim where used

Cleaning degrades over weeks with no visible change

Filter loading, blower performance loss, or drive-belt slip where applicable

Service the filter and inspect blower airflow, pressure, and drive components

Material redepositing downstream

No containment or poor knife angle

Re-aim the knife and add suitable collection or containment

Water spots on the belt after the knife

Moisture carryover in compressed air or insufficient removal geometry

Service or add the appropriate filter/coalescing separator and drain, then verify angle and airflow

Performance drops after a belt change

Cover profile or belt thickness changed the standoff

Reset standoff distance and re-aim the knife

Noise complaints from the work area

Excessive pressure, exposed discharge, worn components, or insufficient enclosure

Verify operating pressure and condition, then add suitable acoustic treatment or enclosure where needed

Accessory support

Air knives are the primary product we supply, while accessories keep the installed system operating correctly. Filters, separators, regulators, shim sets, mounting hardware, replacement blowers, ducting, and related components are available with the unit or as replacement parts. Specify the unit model and length when ordering support parts because shim thicknesses, inlet arrangements, and mounting dimensions vary between designs.

Specifications required for quoting

Provide the following when requesting a conveyor air knife quote:

Belt and conveyor

Application

Plant utilities

Belt width (inches)

Material conveyed

Available compressed air (psig and scfm)

Belt speed (feet per minute)

Contaminant type and approximate volume

Available electrical service at the conveyor

Belt type and cover condition

Operating environment and temperature range

Dust collection or drain tie-in available

Splice type

Duty cycle (hours per day)

Existing cleaner configuration

Available clearance at the mount point

Required outcome (cleaning, dewatering, drying)

Wash-down or sanitation requirements

Photographs of the head pulley, return run, and discharge area can help identify mounting constraints. CAD files of an existing conveyor can shorten the specification process further when available.

Do you need a conveyor solution? Contact Fluent Conveyors

Buy conveyor air knives from the conveyor experts

Fluent Conveyors builds custom conveyors for the world’s most demanding industries. Our team of engineers knows what works and specifies air knives for maximum performance in your operating environment.

Why order from Fluent:

Blower-driven and compressed-air air knives in aluminum, 304 stainless, and 316 stainless
Coverage for belt widths from 12 inches to 96 inches, with joined plenums for wider spans
Retrofit mounting for conveyors from any manufacturer, and factory integration on new Fluent builds
Selection support that accounts for contaminant type, belt condition, duty cycle, and available utilities
Stock air knife components ship in 1–3 business days, and configured blower packages run 2–5 weeks

Ready to work with the experts?

Resources

Installation

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Maintenance

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Guides

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