Introduction to Solids Conveying Eductors

Fox Venturi Products is the leading global supplier of venturi eductors and venturi transport systems for pneumatic conveying of powders, pellets, and bulk solids. They enable the use of low pressure air (below 14 psig or 1 bar) to be used to move powders, pellets, and bulk solids with no moving parts. Fox has sold venturi eductors continuously since our first sale, in 1963, of a stainless eductor for use in transporting plastic pellets with air at 4 psig.

Fox venturi eductor

Fox Venturi Eductors – What Are They?

Fox Venturi Eductors convert the output of a blower into suction that can be used to entrain and feed powders, pellets, and bulk solids into a pneumatic conveying system. Because they have no moving parts, they can operate almost entirely maintenance-free. The eductor acts to compress the air/solids mixture to a pressure adequate to overcome losses in the downstream convey line.

How Are They Used In Pneumatic Conveying Systems?

Fox Venturi Eductors are used to feed bulk solids, such as powders, pellets, flakes, and particulates, into positive, dilute-phase conveying systems. They are commonly used in place of rotary valves where airlocks simply cannot perform adequately.

Eliminating the rotary airlock, left, with a Venturi eductor, right, permits product feed with no moving parts for maintenance-free conveying.

For detailed information on eductors – Download Bulletin 301 or request that we mail you a full color, hard copy of Bulletin 301.

Why Are Eductors Used In Pneumatic Conveying Systems?

Fox Venturi Eductors Have No Moving Parts – allowing for maintenance-free feeding of bulk solids. In applications involving fine, abrasive, or irregularly-shaped products, this is an enormous advantage. Replacement of existing rotary airlocks with venturi eductors makes for simpler, more reliable conveying systems. Designing with eductors from the beginning ensures the most reliable product feeding available.

No Blowback – All rotary airlocks have blowback. If the product conveyed is fine or abrasive, blowback can cause extreme wear problems. Even with free-flowing products, blowback can be a problem, causing bridging and housekeeping problems, or even an explosion hazard. When installed beneath baghouses, screw conveyors, or dust collectors, airlocks can be a major source of fugitive dust emissions, which are eliminated after a retrofit to Fox eductors.

No Mechanical Shearing – Eductors minimize the shearing, smearing or degradation of product common with rotary airlocks. And, of course, safety is simply not a concern with Fox eductors.

That’s all very interesting…
But Can Venturi Eductors Convey My Product?
Let’s start with the letter: A

Fox maintains an up-to-date datbase of all installations made with Fox venturi eductors: about 4000 listings in 2009. Below is a partial list of only those products conveyed beginning with the letter ‘A.’ Note that each individual listing, such as ‘activated carbon’ could actually represent as many as 200 individual installations. Please have us check our database to see if we have conveyed your product!

Abrasive/Blast Grit
Absorbent, SAP polymer
AC Base
Acid Pellets
Acid Powder, Organic
Acrylic Acid/Copolymer
Acrylic Flake
Act Carb +Hy’d Lime
Activated Carbon
Activated Charcoal
Adhesive, Dry
Adipic Acid
Ash & Limestone
Ash Flyash
Ash + Cement
Ash, Flyash at 300°F
Ash Conditioner Additive
Ash, Boiler
Ash, Bottom
Ash, Filter
Ash, Pyrolized
Ash, Rice Hull
Aspartic Acid
Alumina Silica Powder
Alumina Silicate
Alumina Slugs
Alumina Sulfate
Alumina Trihydrate
Aluminium Chips
Aluminum Oxide
Aluminum, Shredded
Aluminum Chloride
Aluminum Dioxide
Aluminum Dross
Aluminum Flakes
Aluminum Foil trim
Aluminum Hydrate
Aluminum Oxide
Aluminum Oxide Grit
Aluminum Pellets
Aluminum Powder
Aluminum Silicate
Aluminum Strips
Ammonium Bicaronate
Ammonium Bichromate
Ammonium Chloride
Ammonium Sulfate
Ammonium Triosulfate
Anamol Oxide
Anthracite Fines
Anticaking Agent
Anti-perspirant Powder
Apple Bits
Apple Bits + Almonds
Apple Crumblets
Artificial Sweetener
Asbestos Fines
Ascorbic Acid
Ash & Limestone
Ash Flyash
Ash + Cement
Ash, Flyash at 300°F
Ash Conditioner Additive
Ash, Boiler
Ash, Bottom
Ash, Filter
Ash, Pyrolized
Ash, Rice Hull
Aspartic Acid

We think there’s a pretty good chance we’ve worked with your product!

Where Does MY Industry Use Fox Eductors?

Although we have sold Fox eductors for use into just about every industry that requires bulk solids handling, we can list a handful of industries here where Fox eductors have been used for decades,in many, many installations. We also list relevent Case Studies which you can request, and which describe specific applictions within this industry:

Conveying: Coal, coke, and alternative fuels; Additives for inhibiting slag build-up on boiler tubes; sorbents for SOx reduction in CFB’s; Activated carbon, lime, calcium carbonate, Trona injection for flue gas desulferization (FGD)

Conveying: Minor ingredients to mixing/batching (salt, sugar, spices, vitamins, flavorings, etc.); Milk powders from spray dryers; Coffee beans from bulk bags; Powdered tea from screeners; Rice; Breakfast cereal from coating reels; Snack food extrudate from extruders; Frozen peas from IQF; Whole peanuts from sorters;

Conveying: CKD at up to 800° F; Portland cement at up to 20,000 lbs/hr; Alternate fuel injection (shredded carpets/plastic/tires//paper; biomass, rice hulls.) Kiln spill at 1600° F

Conveying: Plastic pellets with reduced angelhair and fines from hundreds of extruders and compounding lines since 1963; 50+ fiberglass filled pellets with Clean-in-place, ceramic-lined wear resistant eductors; Conveying plastic regrind and flakes that jam airlocks in 10 minutes;

Conveying: Activated Carbon, Sodium Bicarbonate, Hydrated Lime, Pulverized Limestone into ducts and stacks; Sorbent injection in fluidized bed boilers for SOx reduction

Conveying: Hot copper and nickel alloys at 1000°F from calciners; Mica, talc, quartz, and perlite ore from dust collectors; Copper pellets at 400 lbs/ft3 bulk density;

Building Products

Conveying: Phenolic resin and sawdust for chipboard; Gypsum for sheetrock; Pumice powder for grout; Roofing granules;

Conveying: Silica, Glass Frit, Ceramic dust, Mica


Conveying: Foundry dust from dust collectors; Innoculant to cupolas; Metal grit from grinding stations; Sand and bond

How to Use Eductors in a Pneumatic Conveying System

Designing New Systems with Venturi Eductors

As with any conveying system, the three basic questions are: What product? How much? How far? Send us a completed data sheet and Fox engineers will prepare a Performance-Guaranteed quotation on an eductor or a complete conveying system. The quotation will include all relevant operating data.


  • For Rates up to 15-20,000 lb/hr
  • For Distances up to 300 ft

Retrofitting Existing Equipment

Retrofitting existing systems with Fox eductors can result in very significant improvements. These may include:

  • Eliminate airlock wear
  • Reduce product damage/degradation
  • Avoid dust emissions and leakage
  • Facilitate clean-outs if cross- contamination is critical
  • Reclaim otherwise discarded product

Fox Eductor/Blower Sub-Systems

Fox Valve can provide almost all of the equipment necessary to enable easy, quick installation of a fully-guaranteed pneumatic transport system.

A Fox Eductor is driven by a positive displacement blower package
A Fox Eductor and regenerative blower are mounted on a mobile cart.


Fox can provide any type of blower required, as part of a perfectly matched, guaranteed eductor/blower system—including all required accessories, filters, hose, fittings, etc.

Download Bulletin 302 for detailed information about Fox eductor/blower sub-systems, or request that we mail you a color copy. Click to Download Bulletin 302.

Multiple Eductors Driven by One Blower

Eductor systems often use one blower to drive many eductors, making for surprisingly simple systems when handling material from multiple outlets, as is common with dust collectors or cyclones, as illustrated below.

Conveying from Multiclones – One blower drives (16) Eductors, conveying ash at up to 900° with No Moving Parts