API MPMS 2.2C 2002 pdf free download

API MPMS 2.2C 2002 pdf free download.Manual of Petroleum Measurement Standards Chapter 2—Tank Calibration Section 2C—Calibration of Upright Cylindrical Tanks Using the Optical-triangulation Method.
0 Introduction This method describes the calibration of vertical cylindrical tanks by means of optical triangulation using theodolites. The circumference of the tank is determined at different levels by reference to a base line, which may be either a reference cir- cumference measured by strapping or a base line between two stations of a theodolite measured by means of a tape or by an optical method. External circumferences are corrected to give true internal circumferences. The method is an alternative to other methods such as strapping (Chapter 2, Section 2A) and the optical-reference-line method (Chapter 2, Section 2B). 1 Scope 1.1 This part speciÞes a calibration procedure for applica- tion to tanks above 26 ft in diameter with cylindrical courses that are substantially vertical. It provides a method for deter- mining the volumetric quantity contained within a tank at gauged liquid levels. The measurement required to determine the radius may be made internally (Clause 8) or externally (Clause 9). The external method is applicable only to tanks that are free of insulation. 1.2 Abnormally deformed tanks; e.g., dented or non-circular tanks are excluded from this section, API MPMS Chapter 2. 1.3 This method is suitable for tilted tanks up to 3% devia- tion from the vertical, provided that a correction is applied for the measured tilt as described in API MPMS Chapter 2.2A. 2 Normative Reference The following standard contains provisions which through reference in this text, constitutes provisions of this part of Chapter 2. At the time of publication, the edition indicated was valid. All standards are subject to revision and parties to agreements based on this section of Chapter 2 are encouraged to investigate the possibility of applying the most recent edi- tion of the standard indicated below. Members of API main- tain registers of currently valid API Standards.
4 Precautions The general precautions and safety precautions speciÞed in Chapter 2.2A shall apply to this section of Chapter 2. 5 Equipment 5.1 EQUIPMENT FOR MEASUREMENT OF ANGLES Equipment for measurement of angles as listed in 5.1.1 to 5.1.4 below. 5.1.1 Theodolites, with angular graduations and a resolu- tion equal to or better than 5 seconds. Each theodolite shall be mounted on a tripod which is Þrm and stable. The legs of the tripod shall be steadied by means of magnetic bearers when being used for the internal method. Repeat readings shall agree to within 5 seconds. 5.1.2 Low-power laser-beam emitter, equipped with a device such as a Þber-optic light-transfer system and a the- odolite-telescope eye-piece connection, by which the laser beam can be transmitted through a theodolite. The laser beam shall be coincident with the optical axis of the tele- scope. 5.1.3 Heavy weights, to set around the theodolite stations to prevent movement of the tank bottom plate. 5.1.4 Lighting, for use inside the tank to allow measure- ments to be read accurately. 5.2 STADIA 5.2.1 Stadia, 2 m long, such that the graduated length, between two marks, remains constant to within + 0.02 mm, at the temperature at which it is used. Note: Conversion to USC units is not recommended for use of the stadia. 5.3 EQUIPMENT FOR BOTTOM CALIBRATION Either: a. A liquid method, equipment as speciÞed in Appendix E, or b. For a survey method, a theodolite, a dumpy level, a sur- veyorÕs level or water-Þlled tubes.
8.3 Set the reference axis TL optically on the horizontal planes (circles) of both instruments by sighting from each instrument the vertical graticule wires of the other instrument as described in steps 8.4 to 8.7. 8.4 Shut off the laser beam of the laser theodolite and remove the two Þlters of the laser theodolite. 8.5 Adjust theodolite T to set the telescope to inÞnity and illuminate the eyepiece of this telescope with a light source. 8.6 Sight the object lens of theodolite from the telescope of the 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 laser theodolite stations. Note 3: Do not locate wall points where the line through T and L meets the tank wall.