A GEMCO tumble blender mixes by rotating its vessel, so the material lifts, falls and folds over itself with no ribbons, plows or paddles pushing it around. The company builds three vessel shapes, the double cone, the slant cone and the V-shape, and builds each one to order. That means two used units with the same shape can be quite different, so it helps to know what to look for.
This guide explains the three shapes, the sizes and options you will run into, and what to confirm before you send a purchase request. For a general overview of the brand, including its vacuum dryers, see our GEMCO page. If you are comparing blender types, such as ribbon or plow blenders, start with our blenders page.
GEMCO Tumble Blender Shapes Compared
| Shape | How it blends | What to know |
|---|---|---|
| Double cone | A symmetrical vessel moves particles freely without internal baffles. | Low profile, so it needs less headroom. A single access cover makes cleaning and inspection simpler. |
| Slant cone | An asymmetrical vessel adds particle mobility and intermeshing. | Keeps the low profile of the double cone. GEMCO cites blend times up to 33 percent shorter than other designs. |
| V-shape | Two inclined cylinders repeatedly divide and recombine the material. | Each cylinder has its own access cover for loading and cleaning. Popular across many industries. |
GEMCO’s literature cites blend variation of 1 to 2 percent for the double cone and V-shape, and as low as one half of one percent for the slant cone. Treat those as manufacturer figures. Your own result depends on your materials, your fill level and your blend time.
Standard Sizes and Construction
GEMCO lists these standard features for its double cone and V-shape blenders:
- Working capacity: 10 to 300 cubic feet, with smaller lab-scale units also built.
- Vessel: 304 or 316 stainless steel.
- Frame: carbon steel, with stainless steel available as an option.
- Discharge: a butterfly valve.
- Access: an 18-inch access cover.
Used units were built to the specification of the original buyer, so treat these as a baseline rather than a promise. Confirm the actual materials, valve and finish on the unit you are considering.
Sizing a Used Blender for Your Batch
Capacity is the most common point of confusion on a used listing. Ask whether a stated size is the vessel’s total internal volume or its working capacity. GEMCO generally recommends filling a blender to about half of its total internal volume, and its guidance shows the effective range is wider than that and varies by vessel shape and by whether an agitator is used.
Fill level is a measure of volume, not weight, so bulk density matters. A 1,000 pound batch of a powder that weighs 40 pounds per cubic foot takes up 25 cubic feet, which points you toward a vessel of roughly twice that size at a half-fill. Also keep in mind that cohesiveness, angle of repose and particle size distribution have the biggest effect on blend quality.
Options That Change a Used Blender’s Value
Options can matter as much as the vessel shape. These are the ones worth asking about:
- High-shear or intensifier bars: an internal rotating bar that breaks up lumps, disperses fine additives such as colorants and adds liquids. GEMCO lists several types, including slow speed, high speed, liquid-solids, ultra-high speed, two-speed and variable-speed designs.
- Airless spray system: offered on double cone and slant cone blenders for adding liquids.
- Dust-tight discharge valve: a patented GEMCO valve, which helps when dust containment matters.
- Discharge angle and valve size: different angles and sizes help poorly flowing or easily segregated materials leave the vessel cleanly.
- GEMCOMATIC material handling: the drum loading and unloading system that many GEMCO blenders are paired with.
- Finishes and enclosures: internal and external polishes, stainless steel frames and support enclosures.
A bar or spray system is usually easier to buy with the blender than to add afterward, so decide early whether your process needs one.
When a Tumble Blender Is and Is Not the Right Fit
Tumble blenders suit free-flowing powders and granules, including fragile or friable materials that would not hold up to a mechanical blade. They run on low horsepower and need little maintenance. Sticky, pasty or heavily cohesive materials are a different story, and a ribbon or plow blender may serve you better. You can compare those on our blenders page.
What to Confirm Before You Buy
We sell equipment as inspected and as-is, so the more detail you share, the better we can match you. These are the points that most often decide whether a used GEMCO blender fits.
- Nameplate: model, serial number and year. A nameplate photo helps us identify the shape and size quickly.
- Contact surfaces: confirm the vessel material and finish against your product and any sanitary or cleaning requirements.
- Discharge valve: check the type, size and condition, and whether the seat and seals still close tightly.
- Access covers: look at the gaskets and clamps on every cover.
- Drive and frame: check the motor, gear reducer, speed control and the bearings that carry the vessel.
- Bars and spray systems: if installed, confirm the drive, shaft seals and spray nozzles.
- Electrical rating: make sure the motor and controls suit your area classification if you handle combustible dust or flammable materials.
- Vessel interior: look for scratches, pitting, weld condition and product buildup.
- Paperwork: ask for drawings, manuals or cleaning and validation records, if any are on file.
GEMCO Tumble Blender FAQs
What is the difference between a double cone, slant cone and V-shape blender?
The difference is the vessel geometry. The double cone is symmetrical, the slant cone is asymmetrical for faster blending, and the V-shape uses two inclined cylinders that split and recombine the material. All three are tumble blenders and share the same basic gravity-driven action.
How full should I fill a GEMCO tumble blender?
GEMCO generally recommends about half of the total internal volume. The workable range is wider, but it depends on the vessel shape and on whether an agitator bar is present, so check the manufacturer’s guidance for your model.
Do I need an intensifier bar?
It depends on your material. Free-flowing powders that blend easily often do not need one. If your material clumps, if you add liquids, or if a small amount of an additive must spread evenly, a bar is worth having.
Can a tumble blender handle sticky or wet materials?
Usually not well. Materials that stick to the vessel wall do not tumble freely, so a different blender type is normally a better match.
What should I send to get a quote?
Send the model and serial number if you have them, along with your material, batch size, bulk density, required vessel material and any options you need. A nameplate photo helps a lot.
Send Us Your Blender Requirements
Our team can help you find a used tumble blender that fits your batch size, your materials and your schedule. Browse the GEMCO units currently listed, search our full blender inventory, or submit a purchase request with your nameplate details. You can also use our contact form or call +1-866-289-5232.
