Sampling And Testing Of Wool

The most advanced content of the wool industry in Australia is the sampling and subsequent testing of wool.

Australian wool implements bag sampling.

It can be imagined that the annual workload of testing millions of wool packets is enormous.

In order to ensure the authenticity of the test, there are a series of strict requirements for the sampling work of wool. As we have mentioned before, the regional wool brokers are responsible for the centralized management of Australian wool harvest. One of their important tasks is to assist the Australian wool Inspection Bureau's current personnel in the relevant sampling work.

It must be emphasized that the sampling work must be carried out in person or supervised by the staff of the wool Inspection Bureau, and eventually sealed by these personnel and sent to the testing center for testing. Otherwise, the Australian wool Inspection Bureau can only provide test reports instead of wool inspection certificates seen in international trade.

Australian wool sampling is divided into two broad categories.

The first is core drilling.

Almost one hundred percent of Australian wool is subject to such sampling.

Because of the huge workload of sampling, Australia's wool industry has developed fully automated sampling machinery.

The principle of core drilling is to insert the drill pipe from the top of the wool bag into the wool bag.

Because the wool bag is extruded under the action of the machine, the drill pipe can be inserted into all layers of the bag and the sample is removed.

According to international Wool Textile Organization (IWTO) drilling core sampling requirements, each batch of sampling weight of 1000 grams.

Core drilling samples will be used to detect fiber fineness, cleaning rate and grass impurity content.

This set of figures is the basis of the current trade in wool, and the wool produced in any country must be tested in this area.

Unlike other countries, wool sampling is based on core sampling.

The so-called sample grabbing is the random sampling of a number of intact wool samples in the wool bag.

According to the provisions of the International Wool Textile Organization, the sample weight of sample grabbing is 6 kg per sales volume.

There are two uses for such samples. One is to take two further samples in the samples taken from the samples, and finally to prepare at least 60 bristles. The wool cluster is detected by special equipment to get the data of the length, intensity and the percentage of the broken parts, so as to evaluate the quality of the wool more scientifically.

As for the use of these test results, we will give a detailed explanation in the following chapters. Two, display the wool clusters in the specially designed wool exhibition hall, so that the personnel who purchase wool can not only get all kinds of testing data of Australian wool, but also check the real condition of the corresponding raw wool with these data, including the shape, color and other characteristics of wool.

It needs to be emphasized again that the coverage of Australian core drilling is 100%, while that of sampling is about 80%.

This is due to the fact that the detection equipment is not able to detect the strength of the woolen bushes shorter than 55 mm, but most of the side bristles are relatively short, so it is impossible to detect the fur of 100% Australian wool.

The samples were sent to the AWTA in Melbourne and Western Australia for testing after being bagged and sealed by AWTA at the scene.

2. Australian wool detection

1) testing of core drilling samples.

Every batch of Australian wool sold on the market will remove 1000 grams of samples by drilling core sampling.

This sample will be used for the detection of wool base, fineness and grass base. Once the content of hair base is determined, the washing rate can also be calculated.

The concept of "Mao Ji" is to determine the content of pure fiber in raw wool.

As we all know, raw wool usually contains fiber, water, grease, ash and grass.

Wool traders are concerned about fiber content, so judging wool base is one of the most important concerns.

However, in real life, absolutely pure fiber is "invisible, unable to touch".

However, through different kinds of experimental methods, we can define and eliminate all kinds of non fiber components in raw wool, so as to get the pure fiber content theoretically.

The specific methods are:

I) the samples of 1000 grams were divided into two parallel 150 grams of samples after full mixing.

According to international wool

II) 150 grams of raw wool samples were washed by imitation industrial method.

Wash and dry thoroughly, then dry in a 105 degree oven.

The fibers are weighed instantaneously after being thoroughly dried.

By this way, the moisture content in the raw wool can be accurately determined.

At this time, the weight is discharged from the weight of the washed wool.

III) the wool washed and dried is tested for grease and three sub samples are further separated.

One of the 10 grams of samples was tested for ash content, and a 40 gram sample was used for the detection of grass containing impurities. A 40 gram sample was used for fineness detection.

The specific method of oil detection is to determine the oil content through the detection of near infrared equipment.

At present, only the Australian wool inspection bureau uses near infrared technology in commercial detection of wool.

Because the premise of adopting this technology is to have a large number of traditional test data of Soxhlet extraction, because detection data need to find out the corresponding relationship between the readings of near-infrared detection and traditional detection results.

At present, except for the Australian wool Inspection Bureau, Soxhlet extraction is the method used to detect wool fat.

The disadvantage of this method is that it takes a long time, at least 6 hours, while the near-infrared technology takes only 10 seconds, and the Soxhlet extraction solvent is harmful to the human body.

After the oil is tested, the ash and grass impurities are only left in the wool.

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IV) put 10 grams of washed wool in the crucible and put it into the combustion furnace to burn it fully.

Usually 6~8 hours.

When all organic components are burned, minerals in the crucible remain what we call ash.

After weighing the ash material, we can get the weight of ash contained in 10 grams of washed wool.

V) wash 40 grams of wool sample into a specialized equipment, add high temperature industrial soda to stir.

In this process, the high temperature industrial soda ash completely neutralizes the protein material of wool fiber, and the ingredients of grass mixture are plant fiber, so it can be completely preserved.

On this basis, rinsing, drying and weighing the retained ingredients can determine the weight of the grass impurity contained in the detected wool.

From the above II to V process, the non fiber part of the raw wool is removed step by step, although people still can not get the real pure fiber, but in theory, they already have the basis of judging the pure fiber content.

At this point, the amount of pure fiber obtained theoretically is called Mao Ji.

Because of the content of the wool base, the washing rate of raw wool can be calculated by the actual average processing allowance recognized in the industry.

In this series of tests, not only can the number of wool base be obtained, but also the content of grass base and wool washing rate can be obtained.

Up to now, the testing content of core drilling samples has been completed.