API MPMS 4.2:2003 pdf download

API MPMS 4.2:2003 pdf download.Manual of Petroleum Measurement Standards Chapter 4- -Proving Systems Section 2一Displacement Provers.
The base prover volume is determined with three or more consecutive calibration runs that repeat within a range of 0.02% by one of the three following methods—waterdraw. master meter or gravimetric (see API MPMS Ch. 4.9).
For the initial base volume determination of a new, modified, or refurbished prover, more than three calibration runs may be used to establish higher confidence in the calibration. When conditions exist that arc likely to affect the accuracy of the calibrated volume of the prover. (e.g., corrosion. coating loss) the prover shall be repaired and recalibrated. For deposit buildup, which can be cleaned without affecting the surface of the calibrated volume, the provcr need not be recalibrated.
I listorical calibration data should be retained and evaluated to judge the suitability of prover calibration procedures and intervals.
2.3 VALVE SEATiNG
All valves used in displacement prover systems that can provide or contribute to a bypass of liquid around the prover or meter or to leakage between the prover and meter shall be of the double block-and-bleed type or an equivalent with a provision for seal verification.
The displacer-interchange valve in a unidirectional prover or the flow-diverter valve or valves in a bidirectional prover shall be fully seated and sealed before the displacer actuates the first detector. These and any other valves whose leakage can affect the accuracy of proving shall be provided with some means of demonstrating before, during, or after the proving run that they are leak-free.
2.4 FLOW STABILITY
The flow rate must be stable while the displacer is moving through the calibrated section of the prover (see API ,WPMS Ch. 4.8). Some factors affecting flow rate stability include adequate pre-run length. types of pumps in system, operating parameters. etc.
2.5 FREEDOM FROM HYDRAULIC SHOCK
A properly designed prover operating within its design flow range. the displacer will decelerate and come to rest safely at the end of its travel without excessive hydraulic shock to the displacer. displacement prover, and its associated piping.
2.6 TEMPERATURE STABILITY
Temperature stability is necessary to achieve acceptable proving results. This is normally accomplished by circulating liquid through the prover section until temperature stabilization is reached. When provers are installed aboveground, external insulation of the prover and associated piping may be necessary to improve temperature stability.