Oliver Manufacturing
Sources: Oliver Manufacturing (website)
Oliver Manufacturing (La Junta, Colorado) has produced gravity separators since 1930. Family-owned through four generations, the company is the industry reference for air-table density separation in seed, grain, and specialty food processing — including coffee, spices, and cocoa. First documented coffee industry shipment: 1952.
Oliver’s gravity separators are called gravity tables or densimetric tables — generic terms for the technology Oliver helped pioneer. The brand position rests on build quality, longevity, and a product range spanning micro-mill scale (Hi-Cap) through full industrial scale (Maxi Cap Platinum).
The company also manufactures standalone destoners, precision sizers, fluidized bed dryers, Westrup cleaners, and NoroGard seed treaters — but the gravity separator and destoner are the primary coffee dry-mill relevance.
How Gravity Separation Works
An Oliver gravity separator separates particles of the same size by density:
- Air flow — an upward current through the perforated deck keeps lighter particles suspended; denser particles sink to the deck surface
- Vibration — the deck vibrates with eccentric motion, moving particles across the surface
- Deck inclination — the tilted deck causes dense (heavy) particles to migrate downward toward the heavy discharge; light particles ride the air cushion and migrate uphill toward the light discharge
- Fan zones — multiple independently controlled air zones across the deck allow stratification to be tuned along the full separation path; more zones = finer density resolution
All controls — fan speed, vibration intensity, deck inclination and cross-tilt — can be adjusted while the machine is running, allowing operators to dial in separation in real time under full load.
The result is a continuous fan-shaped separation across the deck: the heavy edge produces dense, well-developed beans; the light edge produces floaters, hollow beans, and light defects; intermediate cuts can be taken at any split point.
For coffee: gravity separation removes hollow beans, broca-damaged beans, and under-developed beans that are invisible to optical sorters because their external colour is normal.
Product Lines
Hi-Cap Gravity Separator
Manual controls. The appropriate scale for specialty micro-mills. Four models:
| Model | Deck area | Capacity range (corn) | Fan zones | Weight (base) |
|---|---|---|---|---|
| HC51 | 26” × 59” | ~600–2,700 lbs/hr | 3 | 435–771 kg (range across HC series) |
| HC81 | 32” × 84” | — | 5 | — |
| HC161 | 36” × 95” | — | 5–7 | — |
| HC241 | 45” × 116” | ~14,300 lbs/hr | 7 | — |
Capacities are crop-specific. Oliver quotes lbs/hr for reference crops (corn, brassica). Coffee throughput differs — confirm with Ian Ely for coffee-specific figures.
The HC51 and HC81 are the most likely scale matches for Kaiserblick’s micro-mill. For comparison, the Pinhalense MVF-0 runs 900–1,200 kg/h parchment; the HC81 (5 fan zones) likely covers similar throughput.
Voyager Gravity Separator
Mid-range series with PLC touchscreen, 20 programmable recipes, and VFD variable-frequency drive fan control. Three models:
| Model | Deck area | Capacity (corn) | Weight |
|---|---|---|---|
| GVX1020 | 29” × 60” | ~3,800 lbs/hr | 1,066 kg |
| GVX1040 | 36” × 96” | ~8,000 lbs/hr | 1,525 kg |
| GVX1050 | 45” × 117” | ~15,000 lbs/hr | 1,951 kg |
The Voyager’s recipe database enables repeatable separation thresholds by variety or processing method — useful in a multi-lot specialty mill where settings differ between washed parchment and natural lots.
Maxi Cap Gravity Separator
Industrial scale. Hydraulic controls.
| Model | Capacity (corn) | Weight |
|---|---|---|
| 3600 | ~30,000 lbs/hr | 2,630 kg |
| 4800 | ~42,000 lbs/hr | 3,447 kg |
Not relevant for Kaiserblick. Scale far exceeds any specialty micro-mill.
Maxi Cap Platinum
Maxi Cap with PLC touchscreen and 20 recipes. Same capacity class (~43,000 lbs/hr corn). Not relevant for Kaiserblick.
Destoner
Oliver destoners use a fluidized air bed with a vibrating deck to move heavy contaminants uphill — the opposite direction to light-particle migration in the gravity separator. Stones, glass, and metal are heavier than coffee and collect at the heavy discharge.
- Placed before the gravity separator: removes stones before they enter the density separation zone
- Placed after: final heavy-contaminant cleanup before bagging
- Particularly important before hulling — stones entering the huller cause severe mechanical damage
Central America Contact
Ian Ely — Director of South American Operations
Territory: Mexico, Brazil, Peru, Colombia, Bolivia, Paraguay, Uruguay, Argentina, Chile, Ecuador, and Central America
Email: ian.ely@olivermanufacturing.com
Cell: +55 (51) 99988-0015
No El Salvador distributor or service centre is listed on the website. All regional inquiries and sales go through Ian Ely.
Procurement Notes
- Oliver is the international benchmark for gravity separators — widely referenced in specialty dry-mill decisions worldwide
- Hi-Cap HC51 or HC81 is the likely scale match for Kaiserblick’s micro-mill; Voyager GVX1020 adds recipe automation at modest additional mass and likely cost
- No ES distributor confirmed — contact Ian Ely for local service and logistics options
- Compare with Pinhalense MVF series (900–1,200 kg/h MVF-0) and Cimbria GA series (PLC/recipe, Siemens HMI) for direct gravity separator alternatives
Links
- Dry Milling Equipment — gravity separator context in the full beneficio seco workflow
- Pinhalense — MVF gravity separator series (alternative)
- Cimbria — GA gravity separator series (Siemens PLC/recipe alternative)