Flowmeter with a measuring device implementing a tomographic measuring principle

Patent metadata

Field	Value
Publication number	US-10705171-B2
Application number	US-201816028757-A
Country	US
Kind code	B2
Filing date	Jul 6, 2018
Priority date	Feb 20, 2014
Publication date	Jul 7, 2020
Grant date	Jul 7, 2020

Abstract

A method for operating a flowmeter for determining the flow of a multiphase medium flowing through a measuring tube using a first and a second measuring device, one of which operates on a tomographic measuring principle and one of which uses a measuring principle based on nuclear magnetic resonance. The first measuring device operates in a different manner from the second measuring device, e.g., using a measuring device operating on the measuring principle of pre-magnetization contrast measurement and having a pre-magnetization section with a constant magnetic field. The magnetic field has at least one component perpendicular to the direction of flow of the multi-phase medium and is generated by using magnetic field generating elements, which are arranged around the measuring tube. Additionally, an assembly for exciting nuclear spin by a RF excitation pulse or a RF excitation pulse sequence is part of the measuring device.

First claim

What is claimed is:

1. A method for operating a flowmeter for determining the flow of a multiphase medium flowing through a measuring tube, comprising:
directing a flow of a multiphase medium through a measuring tube having two different types of measuring devices,
performing measurements on the flow with the measuring devices, one of measurements being a nuclear magnetic resonance measurement and another of said measurements being a pre-magnetization contrast measurement,
wherein said pre-magnetization contrast measurement is used to determine an oil fraction of the multiphase medium by one of changing a length of a pre-magnetization section or by varying measuring positions, and
wherein said magnetic resonance measurement is used to determine a gaseous fraction by applying a gradient magnetic field along a z-axis and a y-axis, an x-axis being in a direction of flow through the measuring tube and the z-axis and a y-axis being perpendicular to said x-axis.

2. The method of claim 1 , wherein said pre-magnetization contrast measurement is also used to determine a water fraction of the multiphase medium by said one of changing a length of a pre-magnetization section or by varying measuring positions.

3. The method of claim 1 , wherein said other of said measurements also comprises an electrical capacitance measurement,
wherein said electrical capacitance measurement is used to determine a hydrocarbon fraction and a water fraction of the multiphase medium from a distribution of one of permittivities and conductivity of the medium.

Assignees

• Krohne Ag

Inventors

• Hogendoorn Cornelis Johannes
• Tromp Rutger Reinout
• Zoeteweij Marco Leendert
• Bousché Olaf Jean Paul

Classifications

• G01F1/716 Primary

  using electron paramagnetic resonance [EPR] or nuclear magnetic resonance [NMR] · CPC title

• G01F1/74

  Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid · CPC title

• G01F1/58

  by electromagnetic flowmeters · CPC title

• G01N33/18

  Water · CPC title

• G01N33/28

  Oils {, i.e. hydrocarbon liquids} (edible oils or edible fats G01N33/03) · CPC title