Standard Test Method for non-dispersible matter by mechanical flushing



Usage Wet screening, classification, elutriation, screen section  



Input material Powder, suspensions and sludge  



Number of fractions Standard 1 (max. 3)  


Batch/Quantity of solids 100 to 800 g in one input step

Bedienungsanleitung Deutsch


Principle of functioning

The process provides information of the content of coarse impurities or constituents which are insoluble in water, such as ceramic constituents, metals or heavily compacted pigments.

A sample is mechanically flushed with water through a wire-mesh screen of a specific size until all that remains is a non-dispersible matter of the sampling.

This non-dispersible matter is dried, weighed and the amount of residues is expressed as mg/kg (ppm) of the original sample.

This method delivers rapid results, which can be compared with the stipulated limit values in quality control.

. In some cases, the impurities need to be categorised under an optical microscope on the basis of their colour, form and surface quality. Magnetic constituents can be detected with bar magnets. If these methods do not suffice, the composition of elements in the individual particles on the surface can be determined using X-ray microanalysis (XMA) or energy dispersive X-ray microanalysis (EDX) and their origin established in this way.

Examples for application

The Test Set NDA VACU is used to test inorganic pigments, such as aerosils, silanes and carbons through to zinc oxide.

In some cases, applications with organic polymers are also possible.

The user fills the sample into the glass cylinder. The pigment or filler is fed into the test device in a circular movement by the water jet rotor located in the vessel. The water separates the fine particles from coarse particles and flushes the fines through the sieve. Air is suctioned through the glass cylinder and the sieve at regular intervals.

After the process has ended, the sieve residue is dried in accordance with the guidelines and determined by gravimetric analysis.

Sieves (main series ISO 565, ISO 3310-1). The percentage of impurities is specified specifically and determined to maintain the desired product quality.

The test device TEST SET NDA VACU quickly delivers the result, which can be adjusted within quality control with the specified limit values. The TEST SET NDA VACU is of particular importance for extruded products and for staple fibres. It delivers reproducible results even with the most difficult products.


de_DE en_US