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.
The EML 200 offers 2 models for dry sieving – the EML 200 Pure for general applications and the EML 200 Premium for users who require highly precise and repeatable data. Both models are suitable for test sieves of diameters from 50 to 203 mm. They are built with an elegant housing with a cover that has an inspection glass to allow samples to be observed during sieving.
The EML 200 is electromagnetically driven to provide 3 dimensional sieving action for fast and optimally reproducible results. The sample will be evenly distributed over the entire sieve surface area to ensure optimal use of the sieve openings. The system holds up to 9 test sieves with normal height (50 mm or 2”) or 15 test sieves with reduced height (32 mm or 1”) and a sieve pan. Test sieves with meshes from 20 microns to 125 mm can be provided.
EML 200 Pure
The EML 200 Pure is a plug & play system whereby the user will only need to select the amplitude mode (fine or coarse material) and the timer to begin the analysis.
EML 200 Premium
The EML 200 Premium has an improved dampening system to significantly reduce the transmission of vibrations, allowing the system to operate quietly. The extra-large display offers the user a simple and user friendly interface. The amplitude can be adjusted up to 3 mm. The new EML Premium is ideal for users who demand precision and reproducible sieve analyses.
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!
Accessories to Aid Sieving
Depending on sample material, powder sizes that are below 300 μm (especially <63 μm) may be very cohesive due to strong electrostatic charges. This may cause plugging of the screen openings of the respective test sieves.
The Haver UFA Ultrasonic Frequency Variation is used for the sieving of powders at critical particle size cuts of ≤300 μm. 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 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.