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EP-3974784-B1 - MULTIPHASE FLOW MEASUREMENT

EP3974784B1EP 3974784 B1EP3974784 B1EP 3974784B1EP-3974784-B1

Inventors

  • LIAO, BOHAO
  • Petterson, Torbjörn

Dates

Publication Date
20260506
Application Date
20121025

Claims (5)

  1. A device for measuring parameters (F L , F G ) describing a flow of a fluid medium containing a first fluid (G) and a second fluid (L), wherein the first fluid (G) represents a gas and the second fluid (L) represents a liquid, wherein the gas is air and the liquid is milk, the device comprising: a milk conduit (110) of a milking installation configured to receive and transport the fluid medium through a measurement section (M), a first sensor device (S1), which comprises conductive sensors arranged in the measurement section (M), and which is configured to register a first measure (m1) in respect of the fluid medium; a second sensor device (S2) which comprises conductive sensors arranged in the measurement section (M), and which is configured to register a second measure (m2) in respect of the fluid medium, the second measure (m2) being independent from the first measure (m1), the first and second measures (m1; m2) both being dependent on a flow rate (F G ) of the first fluid (G) and flow rate (F L ) of the second fluid (L) in the fluid medium; and a processor (120) configured to derive the flow rate (F G ) of the first fluid (G) and/or the flow rate (F L ) of the second fluid (L) based on the first and second measures (m1, m2), characterized in that the first measure (m1) represents a first type of physical characteristic of the fluid medium flowing through the measurement section (M) as a speed, and the second measure (m2) represents a second type of physical characteristic of the fluid medium flowing through the measurement section (M), the second type of physical characteristic being different from the first type of physical characteristic, wherein the second sensor device (S2) is configured to measure an electrical conductivity of the fluid in the measurement section (M), and based thereon derive a second measure (m2) representing an estimated ratio between an amount of the first fluid (G) and an amount of the second fluid (L) in the measurement section (M) or wherein the second sensor device (S2) is configured to analyze the fluid medium in the measurement section (M) during a measurement interval, and based thereon produce the second measure (m2) to represent a flow pattern of the fluid medium during said measurement interval .
  2. The device according to claim 1, wherein the first sensor device (S1) comprises at least two separate sensor elements arranged at a known distance from each other to determine the speed of fluid medium.
  3. The device according to any one of claims 1 or 2, comprising a data storage (130) including a look-up table containing representative values of the flow rate (F G ) of the first fluid (G) and/or the flow rate (F L ) of the second fluid (L) for each of a set of pairs of the first and second measures (m1; m2), and the processor (120) is configured to derive the flow rate (F G ) of the first fluid and/or the flow rate (F L ) of the second fluid (L) based on the look-up table.
  4. The device according to any one of claims 1 or 2, wherein the processor (120) is configured to implement an artificial neural network (ANN) modeling a relationship between a set of pairs of the first and second measures (m1; m2) and the flow rate (F G ) of the first fluid (G) and/or the flow rate (F L ) of the second fluid (L).
  5. The device according to claim1, wherein the measurement section (M) comprises a cavity configured to temporarily store an amount of the fluid medium with respect to which amount an electrical conductivity reference measurement is executed.

Description

THE BACKGROUND OF THE INVENTION AND PRIOR ART The present invention relates generally to measuring fluid flows. More particularly the invention relates to a device according to the preamble of claim 1. Measuring a liquid flow is a relatively straightforward task provided that the flowing medium is homogenous, i.e. if there is only a single substance present in the conduit where the flow is to be measured. However, in practice, it is often the case that the flowing medium is non-homogenous, i.e. there is more than one substance present in the conduit. Moreover, the proportions between the different constituents in the flow may vary over time. As a result, it can be rather complicated to determine relevant flow measures. To mention a few examples, such liquid flows are common in milk extraction and transport. The prior art contains various examples of flow measurement solutions. For example WO 01/29518 discloses a solution for carrying out measurements of a pulsating milk flow in a line. Thus, here, the measured medium comprises a gas and a liquid. The line has a measuring region in which at least one parameter of the medium is determined during a measurement. The measuring region, in turn, may contain a measuring chamber in which milk remains after a pulse flow. This allows further analysis of the milk, such as color analysis. US 5,116,119 reveals a solution for measuring milk flows, wherein the liquid is directed to flow through one or more flow channels, while exposing the liquid to electromagnetic radiation. The liquid's transparency to electromagnetic radiation is used to determine a momentary volume of the liquid flowing through each flow channel. The momentary velocity of the liquid flowing through the flow channels is also determined, thereby permitting a determination of the momentary flow rate of the liquid flowing through the flow channels. EP 1 155 610 describes a quantity meter for determining the quantity of liquid flowing through a line. The quantity meter has two electrically conductive elements arranged in the line at a fixed measuring distance from each other. The conductive elements are connected to an electronic circuit. The diameter of the line is such that when the liquid is flowing there through the volume of the line across the measuring distance is completely filled for some time. Furthermore, in the electronic circuit the quantity of liquid flowing through is determined based on the measured electric conductivity of the liquid therein. US 7,155,971 shows a device for determining the volumetric flow rate of milk flowing during a milking process. Here, a cross-sectional area of the milk flow is determined at a first measuring point by means of a sensor, which is arranged outside the flowing milk. The time required by the milk flow, with the determined cross-sectional area, to go from the first measuring point to a second measuring point provided downstream from the first measuring point is measured. The flow speed is then derived from the measured time and the known distance between the first and second measuring points. The volumetric flow rate is determined on the basis of the determined cross-sectional area and the flow speed. FR 2722292 disclose a device and a method for determining the phase proportion of a multiphase fluid comprising means for emitting and means for receiving microwaves, the means being adapted to the variation in composition of the multiphase fluid, processing and control means making it possible to determine directly from measurements of the amplitude and phase shift of the beam having passed through the multiphase medium, the occupancy rate of the liquid phase and/or the gas phase for a given section of the pipe. US 2008/236298 deals with an apparatus for measuring wetness of a wet gas flow or mixture, wherein the apparatus includes a differential pressure based flow meter configured to determine a first volumetric flow rate of the wet gas flow. WO 2006/121480 deals with a method using ordinary flow meters and apply the understanding of their fundamental behaviors in measuring multiphase fluid flow to improve their accuracy. WO 2010/068118 deals with a method and apparatus for measurement of the individual components of a multiphase fluid comprising oil-water-gas mixtures. WO 2009/125412 deals with a system for measuring milk flow at a milking installation. A first electrode and a second electrode are positioned inside a milk conduit and milk flowing in the conduit forms a resistive element between the electrodes. PROBLEMS ASSOCIATED WITH THE PRIOR ART Hence, solutions are known in the prior art for determining a liquid flow in a fluid flow that contains both gas and liquid. Given that the overall liquid flow also is measured it is likewise possible to derive the gas flow based on the prior-art solutions. However, there is yet no fully reliable and efficient solution, which allows online measurement of a gas flow and/or a liquid flow in a fluid flow containing