API MPMS 4.9.2:2005(2015) pdf download

API MPMS 4.9.2:2005(2015) pdf download.Manual of Petroleum Measurement Standards Chapter 4-Proving Systems Section 9—Methods of Calibration for Displacement and Volumetric Tank Provers
Part 2—Determination of the Volume of Displacement and Tank Provers by the Waterdraw Method of Calibration.
6.1.13 Number, ContInuity and Sequence of Calibration Runs
At least three consecutive calibration mis. that meet all the repeatability criteria, are required for the successful calibration of div. placement ptoseis.
Two consecutive calibration runs, that meet all the repeatability criteria, are required for a successful lank prover calibration. Howeser, if the calibration scale is moved, then a thirst calibration run is required.
If any single calibration run does not meet the repeatability criteria, the reason must be ascertained. remedied, and the calibration continued until the repeatability cntena of an unbroken chain of three consecutive calibration runs is achieved.
• A calibration run on a unidirectional prover is a one way pass.
• A calibration run on a hi-directional prover is a round nip.
• A calibration run on a tank prover is one filling or emptying.
Any measured pass is part of the cotvscctAive chain. However, in the case of mishaps, such as, the overflowing of a test measure, forgetting to close a drain valve, opening the wrong valve. missing a temperature, etc.. the displacer may be returned to its previ. otis starting position and that particular pass started ova.
Re-starting a pass can only he done in a stable temperature condition. Therefore, it may be necessary to return the displacer to the bunching chamber before beginning the repeated pass. When a single pass breaks the consecutive chain, either that pass, or the next. may be used to start the next consecutive chain.
Consecutive passes are defined as sequential treasured passes. Due to constraints of time, weather, or other external factors, it is sometimes necessary to suspend the waterdraw calibration between passes. To restart the calibration process the following procedures may be required depending upon the length of time the calibration is saspended:
• The displacer shall be flexed by conducting at least one unmeasured pass.
• Care must be taken to ensure that flowing conditions and temperature are stabilized.
• All test measures shall be refilled, leveled and drained per requirements.
• All vents shall be checked for air and the system rechecked for leaks.
• The flow rate required for the calibration shall continue in the established sequence.
In the case of a sudden shutdown of the system during a calibration pass ne.g. pump failure, electrical failure. etc.). the test inca- sure filling-valve shall immediately be closed so that air is not pulled into the system. If flow can be restored within a very short penal of time (e.g.. re-setting an electrical breaker etc.) then the pas.s can be continued, However, should a longer period of time be required to restore the system (e.g., replacement of the pump. restoration of the electrical power, escj, then the procedure for a mishap to the pass, or the procedure for the suspension of a calibration, shall be followest However, if the delay will be protracted, then the calibration shall be abandoned and restarted when the system has been fully restored.
If a displacement prover has multiple volumes, each volume shall be considered to be a stand-alone and independent prover volume. Each of these prover volumes shall be calibrated by a separate and independent waterdraw calibration. Each calibration shall meet the same criteria as described above. Reference Figure 2 in API MPMS Chapter 4. Section 9, Part I, lntmduction. for vanou.s detector switch configurations on multiple volume prosers.
6.1.14 Calculations and RepeatabilIty
Detailed calculation procedures are not included in this standard. For the complete details of the waterdraw method calculations, applicable to this standard, refer to the latest edition of the API MPMS Chapter 12. Section 2, Part 4. “Calculation of Base Prover Volumes by the Waterdraw Method.”
The Calibrated Prover Volume (CPV) of a unidirectional prover is the corrected volume dtsplaced in passing the displacer from one detector switch to a second detector switch, always in the same direction. The descnbed one-way procedure should be repeated until satisfactot repeatability of at least three calibration pa.ss/runs is achieved.