Eductors for Pneumatic Conveying with No Moving Parts
Fox Venturi Products (Fox Valve) has been the leading global supplier of venturi eductors and venturi transport systems for dilute phase pneumatic conveying of powders, pellets, and bulk solids since 1963. Fox Eductors, also referred to as jet pumps, 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. These venturi eductor systems can be used to convey product at up to 15 tons per hour over distances up to 500 feet.
Fox Venturi Eductors – What Are They?
Fox Venturi Eductors are used to feed powders, pellets, and bulk solids into a pneumatic conveying system. Because they have no moving parts, they can – and often do! – operate almost entirely maintenance-free. Feedback from customers often reveals five, ten, or even fifteen years of maintenance-free operation.
How Are They Used In Pneumatic Conveying Systems?
Fox Venturi Eductors are used to introduce bulk solids such as powders, pellets, flakes, and particulates into positive pressure conveying systems. They offer end users and system designers a way to eliminate rotary valves from conveying systems where rotary airlocks/rotary valves simply cannot perform adequately. This often occurs with very fine, abrasive, fragile, or high-temperature solids.
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/rotary valves have blowback – also known as fugitive dust or leakage. 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/Product Damage – Eductors minimize the shearing, smearing or degradation of products common with rotary airlocks. And, of course, safety is simply not a concern with Fox eductors.
Where Does My Industry Use Fox Eductors?
Although we have sold Fox eductors/Venturies/Jet Pumps for use in just about every industry that requires pneumatic conveying, we can list a handful of industries here where Fox eductors have been used for decades, in many, many installations. Please visit our Case Study Request Page to request detailed application information about Venturi conveying systems in your industry.
Conveying: Activated carbon, lime, calcium carbonate, Trona and other additives for flue gas desulferization (FGD,) coal, coke, biomass, chopped tires and other alternative fuels; sorbents for SOx reduction in CFB’s
Conveying: Milk and non-dairy powders from spray dryers; Coffee beans, starch, sugar from bulk bags; Powdered tea from screeners; Rice; Breakfast cereal from extruders and dryers; Snack food extrudate from extruders; Frozen peas from IQF; Whole peanuts from sorters; Minor ingredients to mixing/batching (salt, sugar, spices, vitamins, flavorings, etc.;) Recycled product from packing rooms
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: Since 1963, Fox Eductor Systems have been conveying plastic pellets with reduced angel hair and fines from hundreds of extruders and compounding lines; Fiberglass/Mica filled pellets with clean-in-place, ceramic-lined wear resistant eductors; Conveying plastic regrind, chips, and flakes reliably with no moving parts.
Conveying: Activated Carbon, Sodium Bicarbonate, Hydrated Lime, Trona, Pulverized Limestone into ducts and stacks; Sorbent injection in fluidized bed boilers for SOx reduction
Conveying: Copper and nickel alloys at 1000°+ F; 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 sheet rock; Pumice powder for grout; Roofing granules; Sand, ceramic, and aggregate for floor tiles
Conveying: Silica, Sand, Glass Frit, Ceramic dust, Mica
Foundries
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.
Limitations:
- 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.
Blowers
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.
See the latest from our Solids Conveying Eductors Blog!
- One blower drives three eductors for handling abrasives
In a vastly simplified conveying arrangement – compared to any possible option with rotary valves – one blower is used to simultaneously drive three ceramic-lined eductors. Each eductor is under a different hopper. Each eductor then conveys the abrasives to a different destination. The result – three conveying systems, only one blower with no moving parts.
- Tool-steel lined Eductor conveys aluminum chips
Aluminum chips, although a soft metal, can be extremely abrasive when conveyed at rates of 5 tons/hr. Fox is supplying conveying eductors with replaceable ceramic liners as well as replaceable tool steel liners. In addition, some portions of the eductor internals are clad with tungsten carbide.
- Synthetic Wood Manufacturer uses Fox Eductors to convey resin
This major producer of synthetic wood and decking has installed another Fox eductor in their new manufacturing line to convey resin pellets with no moving parts – so their production can continue with no maintenance shutdowns from resin conveying. This is just another of many producers of building products that use Fox venturi eductors – including producers of roofing tiles, sandpaper, chipboard, and grout.
- Larger eductor after conveying dough pellets in Thailand since 2006
A major food processor in Thailand has been using Fox 4 inch, fully sanitary, food grade eductors to reliably convey dough pellets, since 2006. Pleased with their service, they recently ordered a 6 inch sanitary eductor for a new production line. Air is supplied to the eductors from reliable, maintenance-free regenerative blowers, from Fox Valve.
- Still conveying graphite flakes after 24 years of service
One of the world’s largest manufacturers of graphite powders has been using Fox Solids Conveying Eductors to convey graphite from their grinders and screeners since 1998, with almost no wear. Their most recent order was for a 4” eductor to pneumatically transport from a large dust collector through 400 ft, to additional processing.
- 33 years later, a Fox conveying eductor handling toner needs replacement
Back in the 1990’s, over one hundred Fox Eductors were installed at one of the largest toner plants in America – pneumatically conveying ultra-fine carbon from screeners, grinders and totes, with no fugitive dust and no blowback. In January 2022, Fox received a call to replace a 3” eductor, which had (finally) worn out. Shipped and installed in under a week.
- More Venturi eductors installed on 3D printing systems
After thorough testing with Fox venturi prototypes, Fox’s customer is now installing dozens of venturi eductors to convey dense metal powders with insert gas on their additive manufacturing products. These high performance eductors include numerous design features to meet exacting customer requirements.