Miscellaneous Mining Items/Tyler Standard Screens

Miscellaneous Mining Items

Tyler Standard Screens.jpg - TYLER STANDARD SCREEN - Set of three standard screens, 3 in. dia. laboratory size, 1 1/4 in deep with 3/8 in. flange on bottom, all brass with brass wire screens, 1st marked U. S. STANDARD SIEVE SERIES, OPENING 149 MICRONS, U.S. NO.100, TYLER SCREEN SCALE EQUIVALENT OPENING INCHES 0058, MESHES TO THE INCH 100, THE W. S. TYLER COMPANY CLEVELAND, OHIO and The Tyler Double Crimped Trade Mark; 2nd and 3rd marked THE TYLER STANDARD SCREEN SCALE, OPENING .0029 INCHES, MESHES 200 TO THE INCH, U.S. SIEVE SERIES EQUIVALENT, OPENING MICRONS 74, U.S. NO.200, THE W. S. TYLER COMPANY CLEVELAND, OHIO and The Tyler Double Crimped Trade Mark (In preparing a pulp sample for the fire assaying of gold and silver ores, a standard screen is used to ensure, as far as possible, uniformity in the size of the particles of the finely crushed ore. Sieves of various sizes are used to develop the sample fineness. The size to which ore is pulverized is generally stated in terms of mesh, that is, the number of holes per linear inch measuring from centre to centre of the sieve wires. Thus a 40-mesh sieve would have 40 holes to the linear inch, or 1600 to the square inch; and a 90-mesh sieve 90 holes to the linear inch, or 8100 to the square inch. Modern assaying practice tends towards very fine grinding and the use of wire screens of 100 mesh or smaller. Opinions differ as to the degree of fineness to which assay samples should be pulverized, but experience has proved that better results are generally obtained when the samples are crushed finer than was formerly thought to be necessary. There is now general agreement amongst assayers that samples should never be coarser than 80 mesh, and many assayers recommend 100 mesh and some 200 mesh. To maintain consistency in the fineness of the pulp sample, standard screens have been adopted that identify the mesh size and mesh wire diameter. By 1917 the U.S. Bureau of Standards had adopted a standard a 200-mesh sieve made from 0.0021-in. wire, having an opening of 0.0029 in., as the base of the Tyler standard screen scale. Washington S. Tyler started a wire working business in Cleveland Ohio in September 1872 initially known as the Cleveland Wire Works. In 1880 Tyler introduced an improved type of wire cloth, known as Tyler Double Crimped and by 1884 the company was incorporated in Cleveland as the W. S. Tyler Co. Tyler’s next worldwide influence on wire screening was the invention of a new type of screen known as Ton-Cap Screens in 1907. In 1910 Tyler introduced a scientifically designed testing sieve series known as the Tyler Standard Screen Scale Sieve Series. In a short matter of time, this series was adopted as a national standard by the United States and many other countries. Tyler continued to expand its business and in December 1968 the W.S. Tyler Company, and all of it's subsidiaries, had been purchased by Combustion Engineering and by May 1998 all of W.S. Tyler Canada, and the wire weaving divisions of W.S. Tyler in North America, have been 100%-owned by Haver & Boecker. Tyler’s screen series is based on the ratio of 1.414, the square root of 2, as the constant in different sizes of the standardized screen scale. Taking 0.0029 in. or 0.074 mm. the opening in the 200-mesh sieve as the base or starting point, the diameter of each successive opening is exactly 1.414 times the opening in the previous sieve. It also makes the area of surface of each successive opening in the scale just double that of the next finer or half that of the next coarser sieve. In other words, the diameters of the successive sizes have a constant ratio of 1.414 while the areas of the successive openings have a constant ratio of 2. See Algernon Del Mar, Tube Milling, McGraw Hill, 1917, pp 124-131; Rosenqvist, Principles of Extractive Metallurgy, Tapir Academic, 2004, pp 177-182; and Smith, The Sampling and Assay of the Precious Metals, Lippencott, 1913, pp 120-122)

Tyler Standard Screens | TYLER STANDARD SCREEN - Set of three standard screens, 3 in. dia. laboratory size, 1 1/4 in deep with 3/8 in. flange on bottom, all brass with brass wire screens, 1st marked U. S. STANDARD SIEVE SERIES, OPENING 149 MICRONS, U.S. NO.100, TYLER SCREEN SCALE EQUIVALENT OPENING INCHES 0058, MESHES TO THE INCH 100, THE W. S. TYLER COMPANY CLEVELAND, OHIO and The Tyler Double Crimped Trade Mark; 2nd and 3rd marked THE TYLER STANDARD SCREEN SCALE, OPENING .0029 INCHES, MESHES 200 TO THE INCH, U.S. SIEVE SERIES EQUIVALENT, OPENING MICRONS 74, U.S. NO.200, THE W. S. TYLER COMPANY CLEVELAND, OHIO and The Tyler Double Crimped Trade Mark (In preparing a pulp sample for the fire assaying of gold and silver ores, a standard screen is used to ensure, as far as possible, uniformity in the size of the particles of the finely crushed ore. Sieves of various sizes are used to develop the sample fineness. The size to which ore is pulverized is generally stated in terms of mesh, that is, the number of holes per linear inch measuring from centre to centre of the sieve wires. Thus a 40-mesh sieve would have 40 holes to the linear inch, or 1600 to the square inch; and a 90-mesh sieve 90 holes to the linear inch, or 8100 to the square inch. Modern assaying practice tends towards very fine grinding and the use of wire screens of 100 mesh or smaller. Opinions differ as to the degree of fineness to which assay samples should be pulverized, but experience has proved that better results are generally obtained when the samples are crushed finer than was formerly thought to be necessary. There is now general agreement amongst assayers that samples should never be coarser than 80 mesh, and many assayers recommend 100 mesh and some 200 mesh. To maintain consistency in the fineness of the pulp sample, standard screens have been adopted that identify the mesh size and mesh wire diameter. By 1917 the U.S. Bureau of Standards had adopted a standard a 200-mesh sieve made from 0.0021-in. wire, having an opening of 0.0029 in., as the base of the Tyler standard screen scale. Washington S. Tyler started a wire working business in Cleveland Ohio in September 1872 initially known as the Cleveland Wire Works. In 1880 Tyler introduced an improved type of wire cloth, known as Tyler Double Crimped and by 1884 the company was incorporated in Cleveland as the W. S. Tyler Co. Tyler’s next worldwide influence on wire screening was the invention of a new type of screen known as Ton-Cap Screens in 1907. In 1910 Tyler introduced a scientifically designed testing sieve series known as the Tyler Standard Screen Scale Sieve Series. In a short matter of time, this series was adopted as a national standard by the United States and many other countries. Tyler continued to expand its business and in December 1968 the W.S. Tyler Company, and all of it's subsidiaries, had been purchased by Combustion Engineering and by May 1998 all of W.S. Tyler Canada, and the wire weaving divisions of W.S. Tyler in North America, have been 100%-owned by Haver & Boecker. Tyler’s screen series is based on the ratio of 1.414, the square root of 2, as the constant in different sizes of the standardized screen scale. Taking 0.0029 in. or 0.074 mm. the opening in the 200-mesh sieve as the base or starting point, the diameter of each successive opening is exactly 1.414 times the opening in the previous sieve. It also makes the area of surface of each successive opening in the scale just double that of the next finer or half that of the next coarser sieve. In other words, the diameters of the successive sizes have a constant ratio of 1.414 while the areas of the successive openings have a constant ratio of 2. See Algernon Del Mar, Tube Milling, McGraw Hill, 1917, pp 124-131; Rosenqvist, Principles of Extractive Metallurgy, Tapir Academic, 2004, pp 177-182; and Smith, The Sampling and Assay of the Precious Metals, Lippencott, 1913, pp 120-122)

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