API MPMS 4.2:2003(R2015) pdf download.Manual of Petroleum Measurement Standards Chapter 4—Proving Systems
1 Introduction
This document, including figures, graphs and appendices addresses displacement provers. It includes provers that were commonly referred to as either “conventional” pipe provers or “small volume” provers. “Conventional” pipe provers were those with sufficient volume to accumulate a minimum of 10,000 whole meter pulses between detector switches for each pass of the displacer. “Small volume” provers were those with insufficient volume to accumulate a minimum of 10,000 whole meter pulses between detector switches for each pass of the displacer. Displacement provers may be straight or folded in the form of a loop. Both mobile and stationary provers may be con- structed in accordance with the principles described in this chapter. Displacement provers are also used for pipelines in which a calibrated portion of the pipeline (straight, U-shaped, or folded) serves as the reference volume. Some provers are arranged so that liquid can be displaced in either direction. When using a displacement prover the flow of liquid is not interrupted during proving. This uninterrupted flow permits the meter to be proved under specific operating conditions and at a uniform rate of flow without having to start and stop. The reference volume (the volume between detectors) required of a displacement prover depends on such factors as the discrimination of the proving counter, the repeatability of the detectors, and the repeatability required of the proving system as a whole. At least 10,000 whole meter pulses are required for Meter Factors (MFs) derived to a resolution of 0.0001. The relationship between the flow range of the meter and the reference volume must also be taken into account. For provers that do not accumulate a minimum of 10,000 whole meter pulses between detectors for each pass of the displacer, meter pulse discrimination using pulse interpolation tech- niques is required (see API MPMS Chapter 4.6).
1.1 SCOPE
This chapter outlines the essential elements of provers that do, and also do not, accumulate a minimum of 10,000 whole meter pulses between detector switches, and provides design and installation details for the types of displacement provers that are currently in use. The provers discussed in this chapter are designed for proving measurement devices under dynamic operating conditions with single-phase liquid hydrocarbons. These provers consist of a pipe section through which a dis- placer travels and activates detection devices before stopping at the end of the run as the stream is diverted or bypassed.