Importance of Representative Sample and Sample Divider

We receive a lot of foodgrains into our Grain Terminal, Rice Mills Flour Mills and Dal Mills in Bulk form and Bagged form. Grain receiving is a very important activity in any grain business whether storage or milling as profitability of the grain business depend solely on this activity. Receiving a good quality food grain means longer storability, far better milling yield, and minimum expenses on fumigation, aeration and ventilation, de-coring, and cleaning. In a nutshell, you save a lot.

Grain quality assessment plays a very important role in ensuring that you receive only good quality grain. One should have well defined Standard Operating Procedures to access the Grain Quality while receiving the grain. In India I have seen many people bypassing standard operating procedures to access grain quality. And in most cases that I came across, I saw people not giving due importance to Representative Sampling fundamentals which results in incorrect grain sample analysis and results in huge business losses.

Representative Sampling Representative sample is the first stage of Grain Quality Assessment. Representative Sample means a sample that represent the entire grain bulk which is being assessed for quality. If we follow the Representative Sample fundamentals, we can determine the quality of entire lot of grain bulk being assessed with a very high accuracy. There are two very important stages of Representative Sampling. 1. Drawing samples on random basis from various locations of a grain bulk and mixing them together to form a homogeneous sample 2. Dividing this homogenous composite sample into two or more representative samples to initiate quality analysis Samples are collected from Bagged / Bulk vehicles using Hand Probes, Double Sleeve type Triers, Hydraulic Truck Sampling Probes, Hand Scoops, Automatic Screw samplers etc. Samples are collected on random basis from 5-6 locations from a bulk lot and approximately from 10% bags from a bagged lot. Once the sample is drawn from various locations or bags, it is mixed to form a homogeneous mixture and this mixture is called a Composite Sample. You may analyse this sample to assess the quality of grain bulk contained in the vehicle, for parameters like moisture, dockage, weight per thousand grains etc. but this will delay lab analysis as one sample will move from one machine to another. In order to save time and expedite declaration of sample result this composite sample is divided into two or more representative samples. A composite sample when reaches a grain quality lab, it is divided into two or more parts to represent composite sample as a whole so that 2-3 tests can be conducted on composite sample simultaneously like moisture percentage test, dockage test, weight per thousand grains test etc. If we want the analysis results to be accurate then the division of a composite sample into two or multiple samples is highly important otherwise you will never get accurate results.

“YOU MUST NEVER DIVIDE A SAMPLE INTO TWO OR MORE MANUALLY”

When you divide a sample manually it will never lose its representativeness of grain lot and will never give you correct results. Hence scientific division of a composite sample into two or more must be carried out to get accurate quality analysis results. There are two sample dividers that give very accurate results are Boerner Divider and Gamet Centrifugal Divider. They are known to split a composite gain sample with an accuracy of +/-1% which is a fairly high accuracy. Manually division will never give you this accuracy.

Boerner Divider Boerner Divider is a part of grain industry since its inception and one of my favorite sample divider. Boerner Divider is an apparatus that divides a composite sample into two equal representative samples with gravity. The Boerner Divider is calibrated to provide accurate splits of + /– 1% on a 1000g sample. Boerner divider is made from brass and copper, which makes it rust resistant. The legs and supports are powder coated mild steel. Entire bottom section is removable to facilitate cleaning whenever necessary.


To divide a sample into two, sample is placed in the hopper and then released by moving a valve or slide gate located in the hopper throat. The grain through gravity is evenly dispersed over a cone that has 38 pockets or openings. The grain falling down the sides of the cone is cut into 38 separate streams and all these steams rejoins into two streams and empties into the two pans at the bottom. Since the composite sample passes through 38 different streams to later join into two separate streams, it results into two accurate representative samples that are then collected in two pans for further processing.


Boerner Divider

Gamet Centrifugal Divider Gamet Centrifugal Divider is another very popular sample divider, it uses centrifugal force to mix and scatter the grains over the dividing surface. In this divider the grains flow downwards through a hopper into a shallow neoprene rubber disc. When this neoprene rubber disc is rotated by an electric motor the grains are thrown out by centrifugal force and fall downward. The circle or the area where the seed fall is equally divided into two parts by a stationery baffle so that one half grains fall into one spout and another half in another spout. All wearing parts are made of brass & body of high finish stainless steel, base of painted cast iron. Hopper and cylinder top lift off together providing easy access to inner parts for cleaning.

Sample Divider
2-Way Gamet Sample Divider

Gamet Dividers are fast and accurate to within 1/10th of 1% of the total sample by weight. These dividers can significantly reduce the length of time it takes one employee to handle and divide larger samples.


Sample Divider
4-Way Gamet Sample Divider

Gamet Centrifugal Dividers can divide the sample into 2 or 4 representative samples hence these dividers eliminate the need to divide samples many times as with the traditional gravity type Boerner dividers. Both the sample dividers divide a composite sample into two representative samples. This activity should never be bypassed as this ensures the accuracy of your Grain Analysis.


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