API MPMS 2.2C:2002 pdf download

API MPMS 2.2C:2002 pdf download.Manual of Petroleum Measurement StandardsChapter 2—Tank Calibration Section 2C—Calibration of Upright Cylindrical Tanks Using the Optical-triangulation Method.
E.1 Principle
Bottoms of tanks are calibrated by the introduction into the tank of quantities of waier 01 another nonvolatile liquid. which have been accurately measured, until both the dipping datum-point and the highest point of the tank bottom have been covered.
E.2 Equipment
E.2.1 Meter. either having a known meter factor or with an appropriate means of proving being available on site.
E.2.2 Liquid-tight piping, of suitable length to convey the liquid from its source to the meter and thence to the tank.
E.2.3 Dip-tape and dip-weight, as speci& in F. I and F.2.
E.3 Procedure
E.3.1 Set up the meter (E.2.l) on site and connect it to the calibration-liquid source using the liquid-tight piping (E2,2). If the meter is tobe proved on site, prove it by using an appropriate method, with the liquid to be used in the calibration of the tank, before commencing the tank calibration.
E.3.2 Introduce the liquid into the tank bottom until the liquid just covers the dip-point, ensuring that the piping between the meter and the tank bottom is filled before first delivery. Note, from the mctcr reading, the volume of liquid transferred to the tank, to obtain the volume of the tank below the datum-point.
E.3.3 Transfer further measured quantities of liquid into the tank until either the highest point of the tank bottom is covered or the liquid level is higher than the lowest point on the tank that will be calibrated by strapping. On completion of the transfer of each measured quantity of liquid, measure the liquid level using the dip-tape and dip-weight (E2.3).
Note: Suluibic waler- or ed-finding ptcs may be of assistance in dctcrmirnng exact hquid kvcLs.
Record the volumes of liquid introduced and the liquid level measurements.
On completion of the calibration. ensure that the piping between the meter and the tank bottom is full of liquicL
E.3.4 After calibration of the tank bottom, re-prove the meter. If the meter factor has changed such that the vokame of the tank bottom would differ by more than 0.3%. eliminate the caisc of the variation and repeat the tank bottom calibr*ion.
If the meter factor has changed but not sufficiently for the volume of the tank bottom to differ by more than 03%. take the average of the two meter factors and use the average figure in detennining the volumes of liquid introduced into the tank.
E.4 Expression of results
After completing the calibration of the tank bottom, introduce the results into the final calculation of the tank capacity table as described in ISO 7507-1 (see 12.4.2).
F.1 Dip-tape
F.1 .1 The dip-tape shall be made of high-carbon steel having a carbon content of between 0.7% (rn/rn) and 1.0% (rn/rn).
12.4.2 The tape shall have a tensile stzngth of between I
600 Nm’2 and 1 850 Nm’2 and a coefficient of thermal expansionof(l1 ± l)x 104C’.
F.1.2 The tape shall have been calibrated at 20°C and under an applied tension of 15 N. The calibration conditions shall be marked on the tape at w near the iem end of the tape.
F.1.3 The graduations shall be accurate to within 1.5 mm in each 30 rn length when the tape is fully supported on a flat surface at 20°C and subjected to a pull of 15 N.
F.1 .4 T’he tape shall be in one continuous length and graduated on one face only. The tape shall be graduated at intervals of one meter and also at intervals of one decimeter, centimctcr and millimeter.
The length of the graduations shall be as follows:
a. At each meter, across the full width of the tape.
b. At each decimeter, across the full width of the tape.
c. At each centimeter. across two-thirds of the full width of the tape.
d. At each fifth millimeter. across one-half of the full width of the tape.
e. At each millimeter. other than each fifth millimeter, across one-third of the full width of the tape.
The distance from the zero mark shall be marked a every meter. on a bright tablet, at every centimeter and a every decimeter. The size of the numbers used to denote the decimeter graduations shall be larger than those used to denote the centimeter graduations.