Sieves and screens are the oldest and most established method of characterizing the particle size of bulk materials. Using a combination of horizontal and vertical movements by a vibratory motor, samples are separated and retained over a series of screens with different mesh sizes. Subsequently, the individual sieves are weighed to provide an approximate size distribution of the sample.
EML Digital Plus 450 Sieve Shaker
The EML Digital Plus 450 features 3D sieving action for fast and optimally reproducible results. This saves time and avoids the need for manual re-sieving. The EML Digital Plus 450 also features G-Control, which is an automatic acceleration control system to measure and compensate for all natural oscillations of the sieve shaker and subsurfaces to guarantee a constant amplitude for accurate and reproducible data.
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Alternatively, the Ro-Tap provides rotating movement and tapping energy to obtain for consistent and repeatable sieving analysis results. Accessories such as sound enclosure cabinets and dryers for screening materials are also available!
Haver UFA Ultrasonic Frequency Variation is used for the sieving of powders at critical particle size cuts of ≤300 mm. The screen is excited by ultrasonic waves at continuously varying frequencies. These high frequency vibrations reduce the frictional resistance between particles and the screen. Therefore, the tendency to block is reduced, performance of the sieve is increased and the time taken is shortened.
Test sieves need to be cleaned properly prior to provide accurate results. The USC sieve cleaners can reliably provide deep and thorough cleaning of test sieves. The USC 200 and 500 can be used for single sieves with diameters up to 230 mm and 500 mm respectively. The USC 200 Multi can be used to clean up to 5 test sieves with diameters of up to 230 mm simultaneously.
Test Sieves
Test sieves are fabricated according to the valid standards: ISO 565, DIN ISO 3310, ASTM E 11, BS 410, AFNOR, and ISO 5223. They are available in diameters of 76, 100, 150, 200, 203, 250, 300, 305, 315, 350, 400 and 450 mm. Mesh with square aperture widths from 20 μm – 125,000 μm (125 mm) can be supplied.
Test sieves with different mesh shapes are also available. Grid Sieves are used for the determination of particle shape-flakiness index of aggregate particles (DIN EN 933-3 and 1097-8). The stainless steel bar rods with 5.0 mm diameter are arranged in parallel. Slot widths from 2.5 to 40 mm are available. Each Grid Sieve is supplied with a certificate in accordance to DIN EN 10 204.
Test sieves for tobacco are also available to separate coarse pieces of tobacco and other plant materials from cut tobacco. Sieves for cereals are supplied in accordance to ISO 5223.
Alpine Air Jet Sieves are used for extremely fine powders which are too small for conventional test sieves. Air Jet Sieve utilises pneumatic sieving technology, whereby samples of are fluidised by a revolving jet stream. Fine particles are sucked through Air Jet Sieves of 10 μm to 2 mm.
