What is the difference between a grain cleaner and a gravity table?

A grain cleaner with aspiration uses screens and air to remove material such as dust, chaff and straw. A gravity table separates material by specific gravity, such as denser grain from lighter or shrivelled grain. They perform different tasks and may be combined when the process requires both.

Does a destoner remove all foreign material from grain?

No. A destoner is intended to separate stones and other dense contaminants by specific gravity. Other impurities may require screening, aspiration, length grading or colour sorting, depending on the material and target product.

Do all grain cleaning plants need a colour sorter?

No. A colour sorter is considered when discoloured, damaged or visually distinct material needs to be detected and removed. Whether it is appropriate depends on the product, defect and finished specification.

What determines the capacity of a grain cleaning line?

Capacity depends on the crop, incoming material condition, impurity load, required separation outcome, selected equipment and operating pattern. It must be assessed for the complete line and specific application rather than inferred from a single machine name.

Can one cleaner handle grain, seed and dry beans?

The equipment and settings needed can differ between grain, seed and dry beans because material properties and finished requirements differ. Describe each product and target outcome so the equipment configuration can be reviewed for that application.

Grain Cleaning and Sorting: Choose Equipment by Separation Task

Define the incoming material and finished product

Describe the crop, variety or product stream, its condition at intake, and the contaminants or defects that need to be removed. State the desired finished product, the quality or grading requirements you must meet, and whether by-products or separated fractions have a use.

The same machine can produce different results as the incoming product and target change. If the feed varies by source, season or batch, record that variation instead of specifying only a best-case sample. A representative sample and clear acceptance criteria help make an equipment discussion more useful.

Also establish whether the line is cleaning for storage, preparing grain for milling, producing seed or separating a saleable grade. These process goals can call for different combinations of equipment and different inspection points.

Match the separation method to the defect

Each machine targets a particular physical difference. The table is a guide to those roles; it does not imply that every product needs every stage or that one pass will achieve every finished specification.

Grain cleaning and sorting methods by separation principle
Equipment or method	Primary separation basis	Important limitation
Grain cleaner with aspiration	Screen size and air separation for dust, chaff, straw and other light impurities	Does not replace every later stage, such as density or colour separation, where those defects matter
Destoner	Specific gravity separation to remove stones and other dense contaminants	Targets dense foreign material; it is not a general solution for all grain defects
Gravity table	Specific gravity separation to distinguish denser, well-filled grain from lighter material	Product size and feed condition influence performance, so upstream preparation and application review matter
Length grader	Length separation to remove broken grain or foreign seeds of a different length	Separates by length rather than colour, density or every size difference
Electronic colour sorter	Optical detection and ejection of discoloured, damaged or foreign material	Selection depends on detectable visual or sensor differences and the required product outcome

Grain cleaners with aspiration: See Facet Engineering grain cleaner details.
Gravity tables: See density-separation equipment details.
Destoners: See equipment for removing dense contaminants.
Electronic colour sorters: See optical sorting equipment details.

Build a sequence that protects the process

A typical design discussion may consider intake and pre-cleaning first, followed by the specific separation stages needed for the product. Aspiration and dust extraction also need to be considered at the equipment points that generate dust. This is a starting sequence, not a fixed recipe.

Think about what each stage sends forward and where rejects, dust and separated fractions go. Upstream cleaning can protect later machines, while buffer capacity and transfer equipment can help manage differences between receiving, cleaning and packing duties.

For grain-handling areas, include combustible grain dust, potential ignition sources, entanglement and safe isolation for maintenance in the site-specific hazard review. The OSHA source below is US guidance, not a statement of South African legal requirements.

Review how operators will inspect samples and adjust the process. A line should be assessed as a connected flow from intake to storage, further processing or bagging, rather than as a list of independently selected machines.

Grain cleaning plants: See integrated grain cleaning plant scope.
Process equipment range: Browse cleaning, grading and sorting equipment.
Grain cleaning datasheets: Browse equipment datasheets currently published.

Confirm the real application before fixing capacity

Required output, incoming impurity load, product condition, separation targets and operating pattern all affect line selection. A machine's nominal capacity is not a substitute for confirming performance against the material and the full process sequence.

Record the target product specification and how you will verify it. Discuss the feed material and the required separation outcome with the equipment supplier before fixing a line configuration or capacity.

Grain cleaning line design inputs

Crop or product type and representative incoming material condition
Known impurities, defects and the separation task for each
Required output grade, specification and downstream use
Incoming and required finished-product rates, plus batch or continuous operation
Expected variability between deliveries, sources or seasons
Available storage, rejects handling, dust extraction and transfer routes
Cleaning, inspection, sampling and operator access requirements
Site layout, utilities and connections to existing or planned equipment

Common questions

What is the difference between a grain cleaner and a gravity table?: A grain cleaner with aspiration uses screens and air to remove material such as dust, chaff and straw. A gravity table separates material by specific gravity, such as denser grain from lighter or shrivelled grain. They perform different tasks and may be combined when the process requires both.
Does a destoner remove all foreign material from grain?: No. A destoner is intended to separate stones and other dense contaminants by specific gravity. Other impurities may require screening, aspiration, length grading or colour sorting, depending on the material and target product.
Do all grain cleaning plants need a colour sorter?: No. A colour sorter is considered when discoloured, damaged or visually distinct material needs to be detected and removed. Whether it is appropriate depends on the product, defect and finished specification.
What determines the capacity of a grain cleaning line?: Capacity depends on the crop, incoming material condition, impurity load, required separation outcome, selected equipment and operating pattern. It must be assessed for the complete line and specific application rather than inferred from a single machine name.
Can one cleaner handle grain, seed and dry beans?: The equipment and settings needed can differ between grain, seed and dry beans because material properties and finished requirements differ. Describe each product and target outcome so the equipment configuration can be reviewed for that application.

References and safety scope

United States Occupational Safety and Health Administration (OSHA) guidance
Grain handling safety
Guidance covering combustible grain dust, ignition sources, entanglement hazards and lockout.

The linked references are guidance from the jurisdictions named above, not South African legal compliance advice or a Facet Engineering certification. A site-specific risk assessment and applicable local regulations govern equipment and plant design.

Grain cleaning plants: Explore integrated cleaning plant scope.
Process equipment: Browse cleaning, grading and sorting equipment.
Process equipment datasheets: Browse published datasheets.
Discuss a grain cleaning requirement: Contact Facet Engineering about a product or plant.

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