API RP 13E:1993(R2001) pdf download.Recommended Practice for Shale Shaker Screen Cloth Designation
The screen cloth sample should have a minimum area of3 square inches for ease of handling and be approxi- mately equal in width and length. Layered screen compositions built from individual samples should be held between glass slides or oth- erwise fixed so the layers remain in contact and can- not shift during analysis. Confirm under the microscope that the top layer is correctly oriented relative to the bottom cloth and that the warp and shute wires are perpendicular in both layers. Orient the sample to align the screen wires with the x and y axes on the image analysis monitor. Maintain this orientation throughout the remainder of this procedure. Position screen cloth with rectangular apertures 80 that the major axis orientation of both the apertures and the pixels are the same. Because the pixels are rectangular, this maximizes the measurement accu- racy of the image analyzer for this style of cloth.
2.5 Procedure – Magnification Selection a. Select a microscope magnification calibrated to the image analyzer so that the individual pixel difnen- sions are approximately 5% or less of the top cloth’s aperture dimensions. NOTE: As a general guideline for establishing cali- brated magnification settings, select a combination of optics which maximizes depth of field at a magnifica- tion that yields no more than 50 apertures of the top screen cloth visible on the monitor. Calibrate the image analyzer for this magnification if necessary. This usually provides sufficient dimensional accuracy with. out appreciable loss of depth-of-field resolution for most layered screen compositions. b. In some instances the mesh count and wire diameter difference between the two layers is great enough to cause problems in achieving visual resolution of both layers at a suitable magnification level for dimen- sional analysis. This usually occurs when the ratio of mesh counts between the top and bottom cloth ex- ceeds 4:1. In this case, the infrequency of aperture interference caused by the backing cloth will not perceptibly affect the separation potential character- istics of the shaker screen. Use a magnification suf- ficient for accurate dimensional analysis of the finer cloth. Disregard a lack of resolution of the bottom cloth. 2.6 Procedure – Image Enhancement and Proc- essing
API RP 13E:1993(R2001) pdf download
PS:Thank you for your support!
