ASME B40.100:2005 pdf free download

ASME B40.100:2005 pdf free download.Pressure Gauges and Gauge Attachments.
Numerals shall be sufficient in number to enable the operator to accurately and quickly identify any pressure on the scale. They shall not obscure or crowd graduations or important markings.
Numerals shall not extend beyond the calibrated portion of th scale.
Negative (vacuum) values shall be indicated by preceding the appropriate numerals with a minus (—) or clearly marking the dial with the words VAC or VAC. UUM. Uppercase or lowercase letters are acceptable. Both signs and words should not appear on the same scale.
The absence of a sign before a numeral indicates a positive value except when accompanied by the words VAC or VACUL’M.
3.3.2.3 Scale Arcs. The recommended graduated scale arc Is 270 deg. Special applications and ranges may require scale arcs greater or less than 270 deg.
3.3.2.4 Graduation Lines. Graduation lines shall be radial to the center of rotation of the pointer and shall project beyond the arc described by the end of the pointer (mirror and multiple scale diaLs exceptedl. Major and intermediate graduation lines shall be emphasized. Graduations shall not extend beyond the calibrated pmtion of the scale.
Where possible, scale, numeral, and graduation increments should follow the format: I x 1O, 2 x 10”. or 5 x 10”. where ,r is a whole positive or negative number or zero.
The smallest graduation increment should not exceed twice the error permitted (accuracy) in the middle half ot the scale.
3.3.2.5 Graduation Near Zero. On dials for Grades
4A and 3A gauges, there shall be no takeup. The number and the spacing of the minor graduations near zero, shall be the same, commencing at the true zero, as in the rest of the scale. On dials for all other grades, take up may be incorporated. However, if it is incorporated, it shall be readily apparent at what pressure the gradua• tions start. A zero graduation or numeraL or both, shall not be permitted at the stopped pointer position on gauges using a stop pin or internal stops that prevent free pointer motion to the actual zero pressure position,
3.3.3 Pointer
3.3.3.1 Length (AU Grades). The tip of the pointer shall pass within one minor graduation line width of the inner end of the minor graduations.
The pointer may overlap the graduations.
3.3.3.2 Tip Width (Grades 4* and 3*). The width of the pointer tip shall not be greater than the width of the minor graduation lines.