API MPMS 4.9.3:2010 pdf download

API MPMS 4.9.3:2010 pdf download.Manual of Petroleum Measurement Standards Chapter 4- -Proving Systems Section 9- -Methods of Calibration for Displacement and Volumetric Tank Provers Part 3- -Determination of the Volume of Displacement Provers by the Master Meter Method of Calibration.
4.5.6 Flow Rates
The flow rates shall be chosen so that they are within the operating range of the master meter and the master prover. Care should be taken to ensure the displacers in both the master and field prover move smoothly throughout the calibration pass. It is recommended that flow rate changes be based on travel time of the displacer between switches rather than a flow rate indicating device. In addition, between calibration sets, the flow rate shall be changed by an amount that is at least 25 % of the greater of the flow rates of the two consecutive calibration sets being compared. Users may consider changing the flow rate by a percentage higher than 25 % to provide more confidence in the ability of the rate change procedure to discover otherwise undetected leaks. Any flow rate pattern (high, low, high; low, high, low; high, low, lower or low, high, higher) can be followed as long as the flow rates of consecutive calibration run sets differ by an amount that is at least 25 % of the higher flow rate of the pair.
Caution—Give some thought to the flow rates before actually running each calibration run set to prevent inadvertent violation of this requirement. This differs from API MPMS Ch. 4.9.2 (2005) and API MPMS Ch. 12.2.5 (2001) in that here the user is told how to calculate the 25 % change. Flow rates of 800, 600, and 750 would fail this criteria.
The flow rate during a calibration run set should be stable. Maintaining the flow rate of each pass of a calibration run set within a range of 5 % will aid in fulfilling the other repeatability criteria.
4.6 Temperature, Pressure, and Density Device Verification
4.6.1 Temperature Device Verification
Inspect all temperature devices to be used for defects and accuracy.
See API MPMS Ch. 4.9.1 and API MPMS Ch. 7 for more information.
4.6.2 Pressure Device Verification
Inspect all pressure devices to be used for defects and accuracy. See API MPMS Ch. 4.9.1 for more information.
4.6.3 Density Device Verification
The density determination device shall have a scale reading resolution of at least 0.5 kg/rn3 (0.1° API) and its accuracy shall be within 1.0 kglm3 (0.2° API) against a laboratory standard or any device traceable to NIST or appropriate NMI. The current calibration certificate and/or calibration records of the device should be available for review.
4.7 Calculations
See API MPMS Ch. 12.2.5 for complete details of the input precision, algorithm(s), order of calculation and rounding that shall be used to perform the calculations.
This standard assumes a computerized method will be used to organize the data, perform the needed calculations and create the calibration forms.
See API MPMS Ch. 4.9.1 and API MPMS Ch. 12.2.5 for the information that should appear on the calibration forms.
4.8.4.1 Manual Recording
For calibration data that is collected manually for future entry into a computer, the pressures and temperatures for the associated prover and master meter shall be taken as often as necessary, in an equally spaced manner, to obtain average representative values for each associated device during any given pass of the displacer. As a practical matter this means one time for each associated device when the displacer is approximately midway between detectors in very stable process conditions or two or more times when the process is less stable. For example, if three readings are taken, they would be taken at 1/4, 1/2, and 3/4 intervals between the switches where the intervals are based on time or pulses. Multiple readings shall be averaged and reported per API MPMS Ch. 12.2.5.
All manual readings shall be recorded and become a part of the certification package. All readings manually entered into the computer shall be verified against the written records for accuracy and credibility before the calibration documents are signed. See API MPMS Ch. 4.9.1 for detailed information.
4.8.4.2 Automatic Recording
For calibration data that is collected automatically by a computer, the weighted average function may be used to determine and report the associated prover and master meter pressures and temperatures and fluid density during each pass.
5 Other Preliminary Considerations
Since this procedure can take 12 or more hours to complete on large provers, the user should consider performing the appropriate repeatability calculations each time a new proving or calibration run is completed.