Milk meter for measuring milk
Various embodiments provide a milk meter ( 100 ) for measuring milk flow in a milking machine. In an embodiment the milk meter comprises a plurality of ducts ( 140 a, 140 b ) forming a plurality of flow paths through the milk meter. Also, the milk meter comprises a plurality of flow sensors ( 142 ) positioned within the plurality of flow paths. Each flow sensor is operable to measure a flow rate of fluid through its respective flow path. Other types of milk meter are provided in other embodiments.
1 . A milk meter ( 100 ) for measuring milk flow in a milking machine, comprising:
an inlet ( 110 ) for receiving fluid, the inlet ( 110 ) having a first cross-sectional area;
a chamber ( 130 ) downstream of the inlet ( 110 ) for receiving fluid from the inlet ( 110 ), the chamber having a second cross-sectional area greater than the first cross-sectional area;
a plurality of ducts ( 140 ) extending downstream from the chamber ( 130 ) for receiving fluid from the chamber ( 130 ), the ducts forming a plurality of flow paths through the milk meter ( 100 ), the ducts ( 140 ) having a combined cross-sectional area greater than the first cross-sectional area and less than the second cross-sectional area;
the first, second, and combined cross-sectional areas being selected such that when the inlet receives a non-stratified bi-phase flow of fluid, the milk meter ( 100 ) is configured to generate stratified flow of fluid within a stratified flow region in each of the plurality of ducts ( 140 ); and
a plurality of flow sensors ( 142 ) positioned within the plurality of flow paths, each flow sensor ( 142 ) being operable to measure a flow rate of fluid through its respective flow path.
2 . The milk meter ( 100 ) according to claim 1 , wherein the milk meter ( 100 ) is configured to determine a measured total flow rate of fluid through the milk meter ( 100 ) using the measured flow rates from the plurality of flow sensors ( 142 ).
3 . The milk meter ( 100 ) according to claim 1 , wherein the milk meter ( 100 ) comprises an outlet ( 120 ) for releasing fluid from the milk meter ( 100 ), and wherein the plurality of ducts ( 140 ) combine upstream of the outlet ( 120 ).
4 . The milk meter ( 100 ) according to claim 1 , wherein the plurality of flow sensors ( 142 ) comprises a separate flow sensor ( 142 ) positioned within each of the ducts ( 140 ), each flow sensor ( 142 ) being operable to measure a flow rate of fluid through its respective duct ( 140 ).
5 . The milk meter ( 100 ) according to claim 4 , wherein each flow sensor ( 142 ) of the plurality of flow sensors ( 142 ) is positioned within the stratified flow region of its respective duct ( 140 ).
6 . The milk meter ( 100 ) according to claim 1 , wherein a cross-sectional area of at least one duct ( 140 ) is smaller than the first cross-sectional area.
7 . The milk meter ( 100 ) according to claim 4 , wherein each duct ( 140 ) of the plurality of ducts ( 140 ) comprises a downward ramp or step arranged downstream of the respective flow sensor ( 142 ) to reduce fluid backflow through the respective flow sensor ( 142 ).
8 . The milk meter ( 100 ) according to claim 7 , wherein each duct ( 140 ) comprises
a first portion and a second portion downstream of the first portion; wherein
the respective flow sensor ( 142 ) is positioned within the first portion of the duct ( 140 ); and wherein, in use,
the first portion of the duct ( 140 ) forms a first downward gradient, and the second portion of the duct ( 140 ) forms a second downward gradient, the second downward gradient being steeper than the first downward gradient to form the downward ramp or step.
9 . The milk meter ( 100 ) according to claim 8 , wherein the first downward gradient is between 5° and 25° from horizontal, preferably between 10° and 20°, more preferably 15°.
10 . The milk meter ( 100 ) according to claim 1 , further comprising
a conductivity sensor ( 144 b ) arranged to measure a conductivity of the fluid;
wherein each of the flow sensors ( 142 ) is arranged to measure a resistance between two points along the respective flow path to measure a flow rate of the fluid through the flow path, and
wherein the milk meter ( 100 ) is configured to calibrate the measured flow rate from the flow sensors ( 142 ) based on the measured conductivity.
11 . The milk meter according to claim 10 , wherein:
each of the flow sensors ( 142 ) comprises a pair of electrodes arranged to measure a resistance between two points along a duct ( 140 ) of the plurality of ducts ( 140 ).
12 . The milk meter ( 100 ) according to claim 10 , further comprising a pressure sensor ( 170 ) to measure an air pressure within the milk meter ( 100 ), wherein the milk meter ( 100 ) is configured to calibrate the measured flow rate from the flow sensors ( 142 ) based on the measured conductivity and on the measured air pressure.
13 . The milk meter ( 100 ) according to claim 1 , comprising:
a pressure sensor ( 170 ) to measure an air pressure within the milk meter ( 100 ).
14 . The milk meter ( 100 ) according to claim 13 , wherein the pressure sensor ( 170 ) is arranged to measure the air pressure within at least one duct ( 140 ) of the plurality of ducts ( 140 ).
15 . The milk meter ( 100 ) according to claim 13 , wherein the pressure sensor ( 170 ) is arranged to measure the air pressure in a pressure sensing chamber ( 172 ) fluidly connected to at least one duct ( 140 ) of the plurality of ducts ( 140 ), the pressure sensing chamber ( 172 ) being isolated from the duct ( 140 ) by a shield.
16 . The milk meter ( 100 ) according to claim 1 comprising a V-shaped region in each duct ( 140 ), wherein the V-shaped region has a base with a V-shaped cross-section.
17 . The milk meter ( 100 ) according to claim 16 , further comprising a transition region arranged upstream of the V-shaped region, wherein a base portion of the transition region transitions from a rounded cross-section to the V-shaped cross-section along a length of the transition region.
18 . The milk meter ( 100 ) according to claim 16 , wherein:
each flow sensor ( 142 ) comprises a plurality of electrodes arranged within the V-shaped region of the respective duct ( 140 ) to measure a resistance between two points along the duct ( 140 ); and wherein
the electrodes have a V-shaped cross-section commensurate with the V-shaped cross-section of a base portion of the V-shaped region.
19 . The milk meter ( 100 ) according to claim 1 , wherein:
the milk meter ( 100 ) comprises a stagnation well ( 146 ) to generate a region of stagnated fluid; and
one or more sensors ( 144 ) located to measure a characteristic of the stagnated fluid within the stagnation well ( 146 ).
20 . The milk meter ( 100 ) according to claim 19 , wherein:
the stagnation well ( 146 ) comprises a concave depression formed in a base of a duct ( 140 ) of the plurality of ducts ( 140 ) of the milk meter ( 100 ).
21 . The milk meter ( 100 ) according to claim 19 , wherein
the one or more sensors ( 144 ) include at least one of a temperature sensor ( 144 a ) and a conductivity sensor ( 144 b ).
22 . The milk meter ( 100 ) according to claim 19 , wherein
the one or more sensors ( 144 ) includes a temperature sensor ( 144 a ) to measure a temperature of the fluid, and
wherein the milk meter ( 100 ) is configured to calibrate the measured flow rate based on the measured temperature.
23 . The milk meter ( 100 ) according to claim 22 , wherein
the one or more sensors ( 144 ) includes a conductivity sensor ( 144 b ) to measure a conductivity of the fluid and
wherein the milk meter ( 100 ) is configured to calibrate the measured flow rate based on the measured temperature and the measured conductivity.