Sieves Tyler

Screening. A 100-g sample of mica is usually used for this test, plus a rack of six Tyler sieves and a pan. The stack of sieves containing the sample is rotated, and after screening, the mica remaining on each screen is weighed and the percentage retained is calculated. A combination of wet and dry screening may also be used to determine particle size distribution of fine mica (<0.147 mm ( — 100 mesh)). 

The sample is wet-sieved through a Tyler 300-mesh phosphor-bronze twilled-wire-cloth sieve which passes material finer than 50 /z. All the clay and the finer portion of the silt are washed through the sieve into a 1-liter sedimentation chamber. The silt remaining with the sands is dry-sifted through another 300-mesh Tyler sieve, added to a series of sand sieves. 

Compute the size-distribution of the suspension, assuming 87.8 percent is less than 200-mesh Tyler sieve. 

Table 20—Moment Method for Computing Average Mesh Size of Crushed Quartz. (Tyler Sieve Series)...

Figure 24. Summation Curve of Material Passing 65- and Retained on 100-mesh Tyler Sieves.

Calculate the calibration size (weight basis) for a sand (p = 2.64) passing a 200-mesh and retained on a 325-mesh Tyler sieve, given the following size-frequency distribution ... 

Calculate the amount of water vapor adsorbed by silica gel which has passed 14- and is retained on 20-mesh Tyler sieves in 20 min, assuming a 3-in. thickness of the substance in a frame 3 ft X 3 ft in area, the approaching air velocity being 100 lfm and the relative humidity 60 percent. 

Determine the specific surface of 14/20-mesh Tyler sieved sand (p = 2.65). For 200/325-mesh. 

Equations 2.34 and 2.35 allow for transformations between mesh number and aperture size. Both features of sieves are listed in standard screen scales. Standardized sieve apertures were first proposed by Rittinger (1867). Modem standards are based on either a-Jl or progression. In the United States, the series of sieves with standard opening sizes are called "Tyler" sieves and the openings of successive sieves are based onayfz progression starting at 45 pm. 

Tyler sieve (Box 4.5) and weighed. Twice the weight is the Hardness Number. Values should range from 90 to less than lOO . ... 

Abrasion Number - This measurement is made around the same exposure which produced the Hardness Number. One measures the particle size distribution using a set of Tyler sieves before and after the wearing exposure. The Abrasion Number is the ratio of the final mean particle diameter to the initial mean particle diameter, expressed as a percentage. Change of mean diameter should not exceed 30%. Both hardness and abrasion resistance are functions of... 

Tyler sieves, in which the ratio between the mesh sizes of successive sieves in the series is 2 thus the areas of the openings of each sieve are double those of the next finer sieve. 

Tyler Sieve. See under sieve for mesh sizes see Appendix E. 

Size distribution 6 to 14 mesh (Tyler-sieve series)... 

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