Boerner-Type Rotary Sample Divider

What is the Boerner-Type Rotary Sample Divider?

A cone-and-ring divider that reduces free-flowing seed samples into several statistically identical portions. It is the right choice for laboratories that must routinely reduce composite samples before purity, moisture and germination testing.

Overview

The Boerner divider is a conical hopper whose surface carries a series of channels or flutes. When sample is poured in, it flows down the cone and is divided by the flutes into a ring of containers around the base, each receiving successive small increments from the whole stream. This makes each portion a scaled copy of the original, even when particles differ in size and density, and it avoids the bias of scooping from a pile. The divider can be rotated between pours to distribute material further, and different models accept a range of sample volumes from a few hundred grams to several kilograms. It is widely used to reduce composite samples to the working sample mass required by seed testing rules, and its effect can be checked by dividing a sample and recombining portions. Cleaning between samples is important because fine seed lodges in the channels.

How does it work?

Representative sampling depends on taking many small increments from different positions in the lot and combining them into a composite, then reducing it without changing composition. Bag triers are pushed into sacks and withdraw a core that includes material from several depths, while multi-slot versions take a column at once. For bulk lots, a probe or pneumatic sampler withdraws grain from several points and depths, and automatic in-line samplers divert a measured portion of a flowing stream at intervals so that the whole throughput is represented. Composite samples are then reduced with a divider. A Boerner-type divider spreads material over a rotating cone so it falls evenly into a ring of containers, while a riffle divider passes it through alternating chutes. Both avoid the segregation that occurs when a scoop is taken from a pile.

What are the key features?

• Fluted cone divides a flowing stream into equal portions.
• Each portion is a scaled copy of the composite sample.
• Rotating action further distributes material.
• Handles a wide range of sample volumes.
• Reduces composite samples to working sample mass.
• Avoids segregation bias of scooping from a pile.

What are the technical specifications?

A typical boerner-type rotary sample divider configuration offers dividing principle of Fluted rotating cone, number of outlets of 6–18 containers, sample volume of 0.25–5 L per batch, feed particle size of Up to 15 mm, splitting ratio of Equal portions and repeatability of RSD ≤ 2% between portions. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Boerner-Type Rotary Sample Divider is used in composite sample reduction, working sample preparation, subsample retention for audit and seed lot quality testing. Across the wider Seed Sampling Equipment class, laboratories also deploy it for seed certification sampling, seed lot intake inspection and laboratory submitted sample preparation.

Which standards and certifications apply?

Relevant standards and methods include ISTA Rules Chapter 2 (sampling), ISO 24333 (cereals sampling), ISO 6644 (automatic sampling), GB/T 3543.2 (seed sampling) and AOSA Rules for Testing Seeds (sampling). Certification candidates for this model are CE, RoHS and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Take increments from the required number of positions and depths so that the composite is representative, and record the lot identity, number of increments and sampling date. Keep samplers clean and dry between lots, because a few seeds left in a trier or chute can contaminate the next sample, especially after seed treatment. Avoid sampling in rain or extreme humidity where seed moisture can change, and seal samples in moisture-proof containers immediately. Handle dividers so that all passages are full and free-flowing, and do not overload them. Submit the required mass, and retain a duplicate sample where the scheme requires it. Calibrate balance and weighing equipment used for sample mass, and train staff in the specific trier and divider technique so that results are reproducible between operators.

How do I select the right Boerner-Type Rotary Sample Divider?

Select the Boerner divider for free-flowing seed where a composite must be reduced evenly and reproducibly, especially when several fractions are retained. For sticky or very small samples, a riffle divider may perform better. In an RFQ, specify the sample volume, number of outlets and cleaning needs.

How does it compare with other Seed Sampling Equipment variants?

Match the sampler to the container or stream and to the rule that applies. Bagged seed needs a trier of the right length and slot pattern so that a core from top to bottom is withdrawn; multi-slot triers are faster for large numbers of bags. Bulk lots, bins and trucks need a probe or pneumatic sampler that reaches several depths, and large silos or continuous flows are best served by an automatic in-line sampler that takes timed increments. After sampling, a divider is essential to reduce the composite; choose a Boerner type for free-flowing seed and a riffle type for smaller or more difficult material. Confirm that the sampler and divider meet the sampling scheme required by the certification or testing rules, and that they can be cleaned between lots to avoid variety and seed treatment contamination.