API MPMS 4.3 1988 pdf free download
API MPMS 4.3 1988 pdf free download.Manual of Petroleum Measurement Standards Chapter 4 Proving Systems Section 3-Small Volume Provers.
4.3.1 Introduction The use of small volume provers has been made possible by the availability of high-precision displacer position detectors used in con junction with pulse interpolation techniques (see Chapter 4.6). The small volume prover normally has a smaller base volume than that of conventional pipe provers (see Chapter 4.2) and is usually capable of fast proving passes over a wide range of flow rates. Small volume provers have a volume between detec tors that does not permit a minimum accumulation of 10,00 direct (unaltered) pulses fom the meter. Small volume provers require meter pulse discrimination us ing a pulse-interpolation counter or another technique that increases the resolution (see Chapter 4.6). This may include using provers with both large and small base volumes, depending on the pulse rates of the me ters to be proved. The small volume prover may be used in many applications in which pipe provers or tank provers are commonly used. Small volume provers may be sta ionary or portable. The volume required of a small volume prover can be less than that of a conventional pipe prover when high precision detectors are used in conjunction with pulse interpolation techniques. Pulse-interpolation methods of counting a series of pulses to fractional parts of a pulse are used to achieve high resolution without count ing 10,000 whole meter pulses fr a single pass of the displacer between detectors (see Chapter 4.6.) To achieve the required proving accuracy and repeat ability, the minimum volume between detector switches depends on the discrimination of a combination of pulse-interpolation electronics, detectors, and uniform meter pulses, as well as flow rate, pressure, tempera ture, and meter characteristics. 4.3.1.1 SCOPE This chapter outlines the essential elements of a small volume prover and provides descriptions of and oper ating details for the various types of small volume pro vers that meet acceptable standards of repeatability and accuracy.
4.3.1.2.1 Interule spacing refers to variations in the meter pulse width or space, normally expressed in per cent. 4.3.1.2.2 Meter proof refers to the multiple passes or round trips of the displacer in a prover for purposes of determining a meter factor. 4.3.1.2.3 A meter prover is an open or closed vessel of known volume utilized as a volumetric reference stan dard for the calibration of meters in liquid petroleum service. Such provers are designed, fabricated, and operated within the recommendations of Chapter 4. 4.3.1.2.4 A prover pass is one movement of the dis placer betweeq the detectors in a prover. 4.3.1.2.5 A prover round tip is the result of the for ward and reverse passes in a bidirectional prover. 4.3.1.2.6 A proving timer/counter is a high-speed counter used in double chronometry to measure time with a pulsed signal of known fequency. 4.3.1.3 REFERENCED PUBLICATIONS The current editions of the fllowing standards, codes, and specifcations are cited in this chapter: API Manual of Petroleum Measurement Standard Chapter 4, “Proving Systems,” Section 2, “Con ventional Pipe Provers,” Section 6, “Pulse Inter polation,” and Section 7, “Field-Standard Test Measures” Chapter 5, “Metering,” Section 2, “Measure ment of Liquid Hydrocarbons by Displacement Meters,” Section 3, “Measurement of Liquid Hydrocarbons by Turbine Meters,” and Section 4, “Accessory Equipment fr Liquid Meters” Chapter 7 .2, “Dynamic Temperature Deter mination” Chapter 12.2, “Calculation of Liquid Petroleum Quantities Measured by Turbine or Displace ment Meters”
Te calibrated volume-measurement section of the prover, located between the displacer-position sensors, must be desiged to exclude any appurtenances such as vents or drains. Flanges or other provisions should be included for access to the inside surfaces of the calibrated and prerun sections. Care should be exercsed to ensure and main tain proper alignment and concentricity of pipe joints. Interally coatng the prover section with a coating or platng material that will provide a hard, smooth, long lasting fnish will reduce corrosion and prolong the life of the displacer or displacer seals ad the prover. 4.3.3.2 TEMPERATURE STABILITY Temperature stability is necessary to achieve accept able proving results. Temperature stabilization is nor mally achieved by continuously circulating liquid through the prover secton, with or without insulation. When provers are installed aboveground, the applica tion of thermal insulation will contribute to better tem perature stabilization.
