API MPMS 4.2:2003(2015) pdf download

API MPMS 4.2:2003(2015) pdf download.Manual of Petroleum Measurement Standards Chapter 4-Proving Systems Section 2- -Displacement Provers.
This would require six scale and temperature rcadinp. six calculations, and would take a conudcrablc amount of time to till and drain the sax test mcasures.
lithe prover volume ssould he adjusted up to 100 gallons between the switches, the calibration would require only one lOt) gallon test mcaaure. This will reduce the calibration time and uncertainty.
Othcr things to consider that may mcrease the volume required include:
a. The variance of the actLlal K factor from the manufacturd’s typical publishes] K factor for turbine meters may result in less than 10,000 pulses.
b. Fur small displacement meters. generally less than 4 in.. which use mechanical gearing in their pulse generation train. the volume may need to be increased to the next whole unit of volume per revolution of the meter to avoid the cyclical effects of the clutch calibr.iior, For example. 5 gallon increments on 5 — I gallon-geared meters.
43.4 Displacer Velocittes
Some practical limit to the ma.simum velocity of a displacer must be established to present damage to the displacer and the detectors, Nevertheless, the developing slate of the an advises against setting a firm limit to displacer velocity as a criterion for design. Demonstrated results are better to use as a criterion. The results are manifested in the repeatability and reproducibility of MFs using the prover in question Other considerations include consistency of the prover diameter and prover surfaces along with the friction between the prover and displaccrs sealing surfaces.
4.3.4.1 Maximum DispLacer Velocities
For sphere displaccrs. most operators and designers agree that 10 fl/sec. is a typical design specilication for unidirectional provers, whereas velocities up to 5 fl/sec. are typical in bidirectional provers.
For piston displacers, a maximum velocity of 3flsec. 5 ftsec, is recommended, depending on the design.
Higher velocities may be possible if the design incorporates a means of limiting mechanical and hydraulic shock as the displacer completes its puss.
4.34.2 Minimum Displacer Velocities
Minimum displacer velocity must also be considered. especially for proving meters in a liquid that has little or no lubricating ability, such as gasoline that contains high proportions of arornalics or liquefied petroleum gas, The displacer should move at a uniform velocity between detectors. At low velocities when the lubricating ability is poor, the sealing fluetiort is high, and/or the prover siarfisee is rough, the displacer may chatter.
T)pical minimum sphit displacer velocities for lubncatins fluids arc 0.5 ftscc. — 1.0 ftscc. For non-lubricating fluids such as I.P(is and NOL.s higher minimum velocities will be necessat for sphere type displacers. Minimum sphere displacer velocities can be decreased by using low friction spheres (e.g., Tefionx blends. ctc.). or by honing and polishing the inside of the prover,
Typical minimum piston displacer velocities arc 025 Bjscc.
– 0.5 ftscc. for piston elastomcr cup seals and 0.1 ftscc. or less
for piston spnng loaded plastic cup seals. Minimum velocities
t° O 0.005 ftsec. may be attainable by honing and polishing the
inside of the uver
4.3.4.3 Displacer Velocity Calculations
The velocity of the displacer is dependent upon the internal diameter of thc provcr pipe and the maximum and minimum flow rates of the meters to be proved.
The velocity of the displacer can be calculated as follows.