Sieve opening

Sieve no. Sieve Opening Sieve no. Sieve Opening... 

Sieve designatio n Sieve opening Nominal wire diam. Tyler equivalent desiguatiou... 

Sieves are often referred to by their mesh size, which is the number of wires per hnear unit. The U.S. Standard Sieve Series as described by the American Society of Testing and Materials (ASTM) document E-11-87 Standard Specification for Wire-cloth Sieves for Testing Purposes addresses sieve opening sizes from 20 [Lm (635 mesh) to 125 mm (5.00 in). Electroformed sieves with square or round apertures and tolerances of 2 [Lm, are also available. 

Size or sieve designation Sieve opening Permissible variations in average opening Permissible variations in maximum opening2 Nominal wire diameter3 ... 

Air is drawn thru the pipe to the nozzle (1) air passes thru slot in the rotating nozzle (2) to clean the wire mesh (3). The sieve chamber is sealed by a plastic lid (5). The test material.is raised and fluidized in the space between the wire mesh and the lid (4), Suction is applied to pipe (6) to draw the particles thru the sieve openings... 

Sieve no. Sieve opening Sieve no. Sieve opening... 

Standard Alternate Sieve Opening (mm) Diameter (mm) Designation (mesh)... 

Sieve Opening t Openings Approxl mate Mesh Openings Openings DIN Mesh per Opaningt... 

Kollergang This machine can process both dry and plastic materials. Two heavy rotor discs move across a circular floor plate part of which is provided with sieve openings. The clay is pressed through the sieve which results in intensive mixing. The material behind the discs is continuously scraped loose. 

The common sieves are made of woven wire cloth and have square apertures. The sizes of the sieve openings have been standardized, and currently two different sets of standard series, the Tyler Standard and the U.S. Series ASTM Standard, are used in the United States. The mesh number of a sieve is normally defined as the number of apertures per unit area (square inch). Thus, the higher the mesh number the smaller the aperture. Typical mesh numbers, aperture sizes, and wire diameters are given for the lyier sieves and the U.S. ASTM sieves in Table 1.3. Sieve analysis covers the approximate size range of 37 pm to 5,660 pm using standard woven wire sieves. Electroformed micromesh sieves extend the range down to 5 pm or less while punched plate sieves extend the upper limit. 

Where a closer sizing is required Column 5 shows the Tyler Standard Screen Scale with intermediate sieves. In this series the sieve openings increase in the ratio of the fourth root of 2 or 1.189. 

Size or sieve designation Micron No Sieve opening Inch (approx, equiva- Mm lents) Permissible variations in av. opening (percent = ) Permissible variations in max opening (percent = ) Wire diameter Inch (approx. Mm equivalents) ... 

Table 14—French and German Standard Sieve Openings (Mm)...

For closer sizing it is possible to provide a ratio between sieve openings of y/2. The ratio between sizes of the openings is then y/2 or 1.189, and the difference in areas between two successive openings is about ll/2 times instead of 2, as with the Tyler and U. S. series. Reference to Table 11 shows the refinements possible with the use of the y/2 series. 

Material retained on (mesh) Size of sieve opening (/i) Calibration size (m)... 

Pressure drop due to liquid head above slots, sieve openings, or valve openings. 

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