API MPMS 2.2C:2002 pdf download

API MPMS 2.2C:2002 pdf download.Manual of Petroleum Measurement Standards Chapter 2-Tank Calibration.
8.3Set the reference axis TL optically on the horizontalplanes (circles) of both instruments by sighting from eachinstrument the vertical graticule wires of the other instrumentas described in steps 8.4 to 8.7.
8.4Shut off the laser beam of the laser theodolite andremove the two filters of the laser theodolite.
8.5Adjust theodolite T to set the telescope to infinity andilluminate the eyepiece of this telescope with a light source.8.6Sight the object lens of theodolite from the telescope ofthe laser theodolite L and continue focusing until the grati-cules become visible. Make the vertical graticule wires coin-cide by using the adjusting device on the laser theodolite L.Note 1: The example shows 12 wall points per circumference, refer-ence diagram.
Note 2: T and L are interchangeable theodolite and lascr theodolitestations.
Note 3: Do not locate wall points where the line through T and Lmeets the tank wall.
8.7Repeat the operation from theodolite. Repeat the oper-ation as many times as necessary until the vertical graticulewires coincide perfectly.
8.8The TL axis is now set. Record the relative locations ofthe two theodolites by taking readings of both horizontalscales as the horizontal reference angles.
8.9 Replace the two filters in the laser theodolite and switchon the laser beam. This beam is then used to provide a series of points on the tank wall. Sight these points in turn using theother theodolite; take and record the horizontal-scale readingson both instruments.
8.10The minimum number of points on the tank shell wallper circumference shall be as given in Table 1.These pointsshall not be closer than 12 in.(300 mm) from the verticalweld seam. For each course, there shall be two horizontal setsof points—one set on a circumference at 1/5 to 1/4 of thecourse height below the upper horizontal seam as shown inFigure 3.
8.11 Sight all the points along a horizontal set, as indicatedin Figure 3, by the theodolite and the laser beam; move to thenext level.
Note: This will ensure that cach set of points on the tank wall is atthe same level for a given circumference.
8.12Calculate by difference, the angles a and $ indicatedin Figure 4, for cach of these points.
8.13After completion of optical measurement of all points,re-determine the horizontal distance TL(TL=D) if the origi-nal and final values of TLdo not agree as specified; repeat thecalibration procedures until such agreement is obtained.
8.14Check the axis TLby switching off the laser removingthe filters from the laser theodolite and repeating the opera-tions described in 8.3 to 8.8.The original and final horizontalreference angles shall be within the tolerance specified in10.2. If not,repeat the calibration procedures until a set ofreadings ending in such agreement is obtained. Record theaverage values of the horizontal reference angles.
9Procedures for External Measurement9.1 GENERAL
The measurements shall be related either to a reference cir-cumference using the procedure described in 9.2 or to refer-ence distances measured between pairs of theodolite stationsas described in 9.3.
9.2.2.3 For the reference level, make sightings at the level which the reference circumference was measured, see 9.2.1.
9.2.2.4 For each theodolite station, e.g.. T; sight each of the courses at two levels, one at 1/5 to 1/4 of course height above the lower horizontal seam; the other at 1/s to 1/4 of course height below the upper horizontal seam.
9.2.2.5 Move the theodolite from staion TI to T2 to T3, etc., until the entire circumference is covered. Repeat all the described steps at each station, TI, T2. T3, etc., for each level.
The repeat readings of the horizontal angles recorded in
9.2.2.2 shall agree within the tolerances specified in 10.2 If they do not, repeat the measurements until two consecutive sets agree within this tolerance. Record the average horizon-
tal angle for each of the points sighted.
9.3 REFERENCE DISTANCES MEASURED
BETWEEN PAIRS OF THEODOLITE STATIONS
9.3.1 Set up the two theodolite stations outside the tank,
Figure 6 for eight stations and as described in 6.2, using an optical theodolite, 5.5.1 and a second tripod. The minimum number of stations, T1. T2. etc, per circumference, shall be as
referenced in Table 2.
9.3.2 Determine the horizontal distance T, T2; between the two theodolite stations by using the stadia, T1T2 = D; with the stadia mounted on T2 as described in 6.3.