1、BRITISH STANDARD BS ISO 7507-3:2006 Petroleum and liquid petroleum products Calibration of vertical cylindrical tanks Part 3: Optical-triangulation method ICS 75.180.30 BS ISO 7507-3:2006 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 Jan
2、uary 2007 BSI 2007 ISBN 978 0 580 50063 3 National foreword This British Standard was published by BSI. It is the UK implementation of ISO 7507-3:2006. It supersedes BS 7723-3:1994 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee PTI/12, Petroleum meas
3、urement and sampling. A list of organizations represented on PTI/12 can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confe
4、r immunity from legal obligations. Amendments issued since publication Amd. No. Date Comments Reference number ISO 7507-3:2006(E)INTERNATIONAL STANDARD ISO 7507-3 Second edition 2006-07-15 Petroleum and liquid petroleum products Calibration of vertical cylindrical tanks Part 3: Optical-triangulation
5、 method Ptrole et produits ptroliers liquides Jaugeage des rservoirs cylindriques verticaux Partie 3: Mthode par triangulation optique BS ISO 7507-3:2006 ii iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Precautions . 1 5 Equipment .
6、2 5.1 Equipment for measurement of angles 2 5.2 Stadia . 2 6 Equipment set-up and procedure . 2 6.1 Preparation of tank . 2 6.2 Establishment of calibration conditions 2 6.3 Set-up of theodolites and/or total stations. 3 7 Stadia set-up and procedure . 3 8 Measurement of horizontal distance between
7、two theodolite stations using a stadia . 3 9 Measurement of horizontal distance between two theodolite stations using a total station . 5 10 Procedure for internal optical tank wall measurements. 5 11 Procedures for external measurements. 8 11.1 General. 8 11.2 Reference circumference measured by st
8、rapping 8 11.3 Reference distances measured between pairs of theodolite stations 10 12 Tolerances . 11 12.1 Distances between theodolites . 11 12.2 Horizontal angles 11 12.3 Reference circumference. 11 13 Other measurements for tank calibrations 12 13.1 Tank-bottom calibrations. 12 13.2 Other measur
9、ements and data 12 14 Calculations and development of tank capacity tables 13 14.1 From the internal procedure 13 14.2 From the reference circumference procedure. 13 14.3 From the reference distances between pairs of theodolites 13 14.4 Corrections 13 14.5 Tank capacity table. 13 Annex A (normative)
10、 Computation of internal radii from internal measurements 14 Annex B (normative) Determination of the radius of the circle by the least-squares method. 15 Annex C (normative) Computation of internal radii from reference circumference and external measurements. 20 Annex D (normative) Computation of i
11、nternal radii from reference distances between pairs of theodolite stations 22 Annex E (informative) Calibration uncertainties . 24 Annex F (normative) Procedure for checking the theodolite(s) 36 Bibliography . 38 BS ISO 7507-3:2006iv Foreword ISO (the International Organization for Standardization)
12、 is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be repre
13、sented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are
14、 drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Internationa
15、l Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 7507-3 was pre
16、pared by Technical Committee ISO/TC 28, Petroleum products and lubricants, Subcommittee SC 3, Static petroleum measurement. This second edition cancels and replaces the first edition (ISO 7507-3:1993), which has been technically revised. ISO 7507 consists of the following parts, under the general ti
17、tle Petroleum and liquid petroleum products Calibration of vertical cylindrical tanks: Part 1: Strapping method Part 2: Optical-reference-line method Part 3: Optical-triangulation method Part 4: Internal electro-optical distance-ranging method Part 5: External electro-optical distance-ranging method
18、 BS ISO 7507-3:2006 v Introduction This part of ISO 7507 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 can be either a reference circumfer
19、ence 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 (ISO 7507-1) and the optical
20、-reference-line method (ISO 7507-2). BS ISO 7507-3:2006blank 1 Petroleum and liquid petroleum products Calibration of vertical cylindrical tanks Part 3: Optical-triangulation method 1 Scope This part of ISO 7507 specifies a calibration procedure for application to tanks above 8 m in diameter with cy
21、lindrical courses that are substantially vertical. It provides a method for determining the volumetric quantity contained within a tank at gauged liquid levels. The measurements required to determine the radius are made either internally (Clause 10) or externally (Clause 11). The external method is
22、applicable only to tanks that are free of insulation. This method is suitable for tanks tilted up to a 3 % deviation from the vertical provided that a correction is applied for the measured tilt as described in ISO 7507-1. 2 Normative references The following referenced documents are indispensable f
23、or the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 7507-1:2003, Petroleum and liquid petroleum products Calibration of vertical cylindrical tanks Part
24、 1: Strapping method 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 7507-1 and the following apply. 3.1 total station theodolite with built-in distance meter that coincides with the optical axis of the instrument 4 Precautions The general precaution
25、s and safety precautions specified in ISO 7507-1 shall apply to this part of ISO 7507. BS ISO 7507-3:20062 5 Equipment 5.1 Equipment for measurement of angles 5.1.1 Theodolite, with angular resolution equal to or better than 0,2 mgon (1 mgon = 0,25 s). Each theodolite shall be mounted on a tripod th
26、at is firm and stable. The legs of the tripod shall be steadied by means of magnetic bearers (or any equivalent system) when being used for the internal method. The theodolites shall be checked either periodically or prior to the tank measurements as described in Annex F. Alternatively, a total stat
27、ion can be used along with a prism mounted on the other station. The total station shall meet the same requirements for the angular measurements as the theodolites. The distance measurement shall have a resolution equal to or better than 0,1 mm. The distance meter shall be calibrated together with t
28、he used prism with an extended calibration uncertainty on the order of 1 mm or better. It shall be possible to mount the prism on the tripod in the same position as the theodolite/total station. 5.1.2 Laser-beam emitter, low-power, equipped with a device, such as a fibre-optic light-transfer system
29、and a theodolite-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 telescope. 5.1.3 Weights, heavy, to set round the theodolite stations to prevent movement of the tank bottom plate. 5.1.4
30、Lighting, for use inside the tank to allow measurements to be read accurately. 5.2 Stadia Stadia, at least 2 m long, of a material whose thermal expansion is known. The graduated length between two marks shall be calibrated. Extended calibration uncertainty should be on the order of 0,05 mm. It shal
31、l be possible to mount the stadia on the tripod in the same position as the theodolite. NOTE The stadia is not used when the calibration is carried out using a total station. 6 Equipment set-up and procedure 6.1 Preparation of tank For new tanks or for tanks after repair, fill the tank to its normal
32、 working capacity at least once and allow it to stand for at least 24 h prior to calibration. 6.2 Establishment of calibration conditions If the tank is calibrated with liquid in it, record the depth, temperature and density of the liquid at the time of calibration. Do not make transfers of liquid d
33、uring the calibration. Measure or estimate the worst-case gradient of tank-shell temperatures at the time of calibration. NOTE 1 The temperature gradient is used to estimate the uncertainties of the measured tank radii (see 13.2 and E.3.5.3). NOTE 2 The highest temperature is usually found on the su
34、nny side at the top of the tank, the lowest temperature on the shady side at the bottom of the tank. BS ISO 7507-3:2006 3 6.3 Set-up of theodolites and/or total stations 6.3.1 Set up each theodolite or total station with care, according to the procedure and instructions given by the manufacturer. In
35、 addition, follow the procedures described in 6.3.2 and 6.3.3. 6.3.2 Set up the instrument so as to be stable. For the internal method, steady the bottom of the tank near the theodolite or total station by installing weights or other heavy objects around the station if there is a risk of the station
36、 moving during the calibration. Mount the legs of the tripod on magnetic bearers (or any equivalent system) to prevent the legs from sliding on the tank bottom. For the external method, drive the legs of the tripod fully home into the ground. 6.3.3 Set the bed plate of the instrument as near as poss
37、ible to the horizontal. NOTE This ensures verticality of the swivel axis of the theodolite or total station. 6.3.4 The calibration equipment shall be placed at the site for typically 1 h in order to reach ambient temperature before commencement of the actual calibration procedure. 7 Stadia set-up an
38、d procedure 7.1 Mount the stadia on the tripod with care according to the procedure and instructions given by the manufacturer. In addition, follow the procedures described in 7.2 and 7.3. 7.2 Mount the stadia horizontally and perpendicular to the aiming axis by adjusting the device on the stadia. 7
39、.3 Once setting-up is complete, lock the stadia in position and verify that it is horizontal and perpendicular. 8 Measurement of horizontal distance between two theodolite stations using a stadia 8.1 This procedure for determining the distance using a stadia is not recommended if the distance betwee
40、n the stations is above 25 m. 8.2 Take the measurement prior to the commencement of the optical readings. Set up the stadia as described in Clause 7. Measure the horizontal angle, 2, subtended at the theodolite (see Figure 1) by the two marks on the stadia, using the theodolite. BS ISO 7507-3:20064
41、Key 1 theodolite 1 2 theodolite 2 (laser) 3 stadia mark 4 stadia aPoints T and L are interchangeable. bB, the distance between the two reference marks on the stadia, equals 2 m. Figure 1 Measurement of distance between two theodolites 8.3 Compute the horizontal distance, D, between the two theodolit
42、e stations from Equation (1): 2t a n B D = (1) where B is the distance between the two reference marks on the stadia (corrected for thermal expansion, if necessary); is half the angle subtended at theodolite, T, by the two reference marks. 8.4 Carry out the measurement of the angle 2 and the computa
43、tion of the distance, D, a minimum of five times while turning and re-pointing the theodolite in between, and calculate and record the average value. Two standard deviations of the mean of the distance, D, shall be less than half of the tolerance given in Table 3 or the entire procedure shall be rep
44、eated. 8.5 Re-determine the distance, D, after completion of all the optical measurements described in 10.13. The average distances computed before and after the optical measurements shall agree within the tolerances given in Table 3. If they do not, repeat the calibration procedure until a set of m
45、easurements is obtained with the average values for D at the beginning and end within the tolerances. 8.6 The average of all measurements of distance, D, shall be used in further calculations. BS ISO 7507-3:2006 5 9 Measurement of horizontal distance between two theodolite stations using a total sta
46、tion 9.1 This procedure for determining the distance between theodolite stations is not recommended if the distance between the stations is less than 10 m. 9.2 Set up the prism at the second tripod. 9.3 Carry out the measurement of the distance, D, a minimum of five times while turning and re-pointi
47、ng the total station in between, and calculate and record the average value. Two standard deviations of the mean of the distance, D, shall be less than half of the tolerance given in Table 3 or the entire procedure shall be repeated. 9.4 Re-determine the distance, D, after completion of all the opti
48、cal measurements described in 10.13. The average distances computed before and after the optical measurements shall agree within the tolerances given in Table 3. If they do not, repeat the calibration procedure until a set of measurements is obtained with the average values for D at the beginning an
49、d end within the tolerances. 9.5 The average of all measurements of distance, D, shall be used in further calculations. 10 Procedure for internal optical tank wall measurements 10.1 Set up two theodolite stations inside the tank as illustrated in Figure 2 and as described in 6.3. aT and L are interchangeable theodolite and laser theodolite stations. Figure 2 Example of locations of theodolite stations and wall points for internal procedure 10.2 Locate the t
