US 20100273273A1
(19) United States
(12) Patent Application Publication (10) Pub. No.: US 2010/0273273 A1
Cross et al.
(54)
(43) Pub. Date:
SAMPLING SINGLE PHASE FROM
MULTIPHASE FLUID
(76) Inventors:
Publication Classi?cation
(51)
Peter Stephen Cross, Hamilton
.
.
(NZ); Thomas Frletsch, Ham1lton
Hamllton (NZ)
Correspondence Address_
BLAKELY SOKOLOFF TAYLOR & ZAFMAN
(52)
LLP
(57)
Api‘lgégtzgo (Us)
’
Int- Cl
GoIN 1/10
G01F 23/00
G01N 21/35
(200601)
(2006.01)
(200601)
G01N 1/00
(2006.01)
US. Cl. ........ .. 436/174; 73/290 R; 356/51; 356/436;
356/445; 73/863'02
ABSTRACT
A sampler (1) for extracting sample Volumes of substantially
single-phase ?uid or gas from a ?uid-?oW system containing
_
multi-phase ?uids (3), said sampler (1) including; a collection
(21) Appl' No"
10/592965
(22)
M M 29 2005
PCT F 11 e d,
'
(86)
Oct. 28, 2010
PCT NO;
l
’
PCT/NZ2005/000058
recess (4) adapted to separate substantially single-phase ?uid
from said multi-phase ?uid (3); an extraction outlet (8) in said
collection recess (4); at least one ?uid sensor system (5)
capable of sensing the presence and/or state of said single
phase ?uid or gas in the collection recess (4), a ?uid controller
§ 371 (OX1),
(2)’ (4) Date;
Dec_ 1, 2008
(6) capable of controlling ?uid or gas ?oW from the collection
recess (4) Via said extraction outlet (8), characterised in that
Foreign Application Priority Data
sensors respectively capable of utilising distinct properties of
said ?uid sensor system (5) includes at least tWo distinct
(30)
Mar. 25, 2004
(NZ) ...................................... .. 531794
the ?uid or gas to determine the presence and/or state of the
sample volume present in the collection recess (4).
Patent Application Publication
Oct. 28, 2010 Sheet 1 0f 12
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SAMPLING SINGLE PHASE FROM
MULTIPHASE FLUID
TECHNICAL FIELD
[0001] The present invention relates generally to a sampler,
in particular to a milk line sampler.
BACKGROUND ART
[0002]
Monitoring the constituents and characteristics of
dairy milk, particularly during the milking process itself is of
increasing interest to both producers and consumers. In addi
tion to quantitative feedback on the milk value (determined by
milked animal. This system does not use a sample Well to
extract single phase milk nor consequently does it sense the
speci?c presence of a speci?c volume of single-phase milk to
trigger sample collection.
[0009] It is an object of the present invention to address the
foregoing problems or at least to provide the public With a
useful choice.
[0010] All references, including any patents orpatent appli
cations cited in this speci?cation are hereby incorporated by
reference. No admission is made that any reference consti
tutes prior art. The discussion of the references states What
their authors assert, and the applicants reserve the right to
signi?cant data on blood, Water and fat content, mastitis,
challenge the accuracy and pertinency of the cited docu
ments. It Will be clearly understood that, although a number of
prior art publications are referred to herein, this reference
lactation and other conditions are also of interest.
does not constitute an admission that any of these documents
[0003] Consequential developments in milk line monitor
ing and sampling have produced several prior art techniques,
though these still possess disadvantages.
Zealand or in any other country.
the percentage of fat solids), commercially and health/safety
[0004] It is desirable to sample the milk in the milk line
from the coW Without causing any signi?cant interruption to
the milk ?oW or delay in obtaining the measured data.
[0005] It is also important to obtain accurately knoWn vol
ume samples of milk (or at least to obtain minimum sample
volumes) as part of the testing processes for the various milk
characteristics monitored. Di?iculties arise in obtaining
accurate (or minimum) milk volumes hoWever, as the milk
line ?oW from dairy cattle is not uniform but a largely tWo
phase ?oW of milk and air. Milk ?oW interruptions When a teat
cup become detached from the animal or very loW levels of
milk ?oW also cause major problems in obtaining the mini
mum required sample siZe. The pulsed vacuum action applied
to the teat cups produces a ?uctuating milk ?oW including
solid milk slugs, milk With entrained air and milk/air froth.
[0006] Consequently, determination of the instantaneous
milk/air ratio at any given time is extremely dif?cult. Known
techniques of extracting a measured sample volume such as
disclosed in US. Pat. Nos. 5,572,946 and 5,388,549 Holroyd,
involve opening a ?uid outlet in the milk line at a predeter
mined time period after milking has commenced. The time
period is chosen to correspond to a time When a solid milk
?oW is likely to be occurring and/or, dependant on the purpose
of the sample testing: e.g. taking account of the signi?cant fat
variation betWeen the fore milk and milk from the latter
form part of the common general knoWledge in the art, in NeW
[0011] It is acknoWledged that the term ‘comprise’ may,
under varying jurisdictions, be attributed With either an exclu
sive or an inclusive meaning. For the purpose of this speci?
cation, and unless otherWise noted, the term ‘comprise’ shall
have an inclusive meaningiie. that it Will be taken to mean
an inclusion of not only the listed components it directly
references, but also other non-speci?ed components or ele
ments. This rationale Will also be used When the term ‘com
prised’ or ‘comprising’ is used in relation to one or more steps
in a method or process.
[0012] Further aspects and advantages of the present inven
tion Will become apparent from the ensuing description
Which is given by Way of example only.
DISCLOSURE OF INVENTION
[0013] According to one aspect of the present invention
there is provided a sampler for extracting sample volumes of
substantially single-phase ?uid from a ?uid-?oW system con
taining multi-phase ?uids, said sampler including;
[0014]
a collection recess adapted to separate substan
tially single-phase ?uid from said multi-phase ?uid;
[0015] an extraction outlet in said collection recess;
[0016] at least one ?uid sensor system capable of sensing
the presence of a minimum volume of said single-phase
?uid or gas in the collection recess, and
[0017]
a ?uid controller capable of controlling ?oW from
milking stages. HoWever, this technique is not infallible and it
is possible for the extracted sample to contain a signi?cant
quantity of air.
[0007] Further prior art means of addressing the above dif
the collection recess via said extraction outlet;
characterised in that
a sample volume of said single-phase ?uid or gas is obtain
?culties are disclosed in WO 00/64242 Dommerholt Which,
amongst numerous embodiments, describes a milk-sensing
device using spectrometry to determine milk content. In order
volume to ?oW through the extraction outlet after said ?uid
to perform measurements in non-turbulent single-phase milk,
a light emitter/detector pair is arranged in a sample Well.
Different con?gurations permit either transmission measure
ments or re?ectance measurements to measure changes in
Wavelength and scattering angles. HoWever, there is no means
of extracting a physical sample of the milk from the Well to
able by operating the ?uid controller to alloW the sample
sensor has detected the presence of said minimum volume of
single-phase ?uid or gas in the ?uid collection recess.
[0018] It Will be appreciated that any sensor capable of
sensing the presence of a particular liquid, gas or froth is by
de?nition also capable of detecting an absence of same and
that the present invention should be interpreted to include
such a capacity of the sensors.
perform further testing, nor determining What type of sample
[0019]
is present, i.e. milk, froth or air.
[0008] WO 03/090522 Bosma, HolmertZ also discloses a
milk-sampling device Which utilises a variety of methods to
extract a sample from the milk line including a conduit loop
suitable device or mechanism capable of receiving data input
and uses a timed milk ?oW through a control valve to rinse the
sampler passageWays of any milk residue from the previously
The term ‘?uid controller’ used herein refers to any
from the ?uid sensor system, and performing processing or
logical operations to control the ?oW of ?uid or gas from the
collection recess by operating a valve or pump or the like.
[0020] As used herein, “multi-phase ?uid” includes a mix
ture of gas, ?uid and froth (i.e. ?uid and entrained and/or
Oct. 28, 2010
US 2010/0273273 A1
undissolved gas) Whereas “single-phase ?uid” is ?uid sub
stantially separated from undissolved gases or froth.
[0032]
Numerous forms of knoWn ?uid sensor may be
employed, both invasive (inside the collection recess) and
[0021] It Will be appreciated that although obtaining single
phase ?uid sample volumes is of greatest importance in appli
non-invasive, including optical, electro-optical, electrical
cations such as milk line sampling, the invention is not
restricted to same. The invention may equally be utilised in
applications such as the petrochemical ?eld Where extracting
[0033] In milk sampling applications, the presence of
single-phase milk may be determined by an optical emitter
and detector by measurement of the attenuation of the light
and sampling a gas from a multi-phase ?oW may be of prime
signal transmitted through the ?uid.
capacitance, acoustic, pressure sensors or the like.
importance.
[0034]
[0022]
con?gured to detect the absence of ?uid, preferably including
single or multi-phase ?uid. This con?guration may provide
Equally feasible, albeit With less likelihood of com
mercial importance, is the possibility of deliberately seeking
to extract sample volumes of froth. To maintain clarity, the
invention is largely described herein With respect to the
extraction of single phase sample volumes, though it should
In yet further embodiments, the ?uid sensor may be
continuous data to the ?uid controller on the instantaneous
status of ?uid in the collection recess.
[0035] In one embodiment, a predetermined or minimum
be understood this is for exemplary purposes only and the
sample volume of said single-phase ?uid is obtainable by
invention is not limited to same.
operating the ?uid controller to alloW ?uid to ?oW through the
extraction outlet for a predetermined period after said ?uid
sensor system has detected the presence of single-phase ?uid
at said predetermined level in the ?uid collection recess.
[0036] Preferably, a predetermined or minimum sample
volume of said single-phase ?uid or gas is obtainable by
operating the ?uid controller to alloW ?uid to ?oW through the
extraction outlet until
[0023] In one embodiment, said sampler includes a pump
controlled by said ?uid controller to extract said sample vol
ume from the collection recess.
[0024] In an alternative embodiment, the sampler includes
a valve controlled by said ?uid controller to alloW the sample
volume to pass from the collection recess.
[0025] In applications such as milking Where a vacuum
propels the multi ?uid ?oW in the ?uid ?oW system, a pump is
required to positively remove the single phase ?uid against
the effects of the vacuum. If the multi-phase ?uid ?oW is
propelled solely by gravity, or by an elevated ?uid pressure
(e.g. super-atmospheric air) supply, a simple valve may be
used by the ?uid controller to regulate the ?oW from the
collection recess.
[0026]
The pump may be of variable or ?xed ?uid ?oW rate
throughput, provided the throughput is knoWn to enable the
calculation of an accurate sample volume extraction.
[0027]
[0037] a predetermined time has elapsed;
[0038] a pump operable by the ?uid controller has
pumped said minimum volume from the collection
recess;
[0039]
a second level sensor located at a loWer point in
the collection recess indicates the absence of the sample
volume ?uid or gas; and/or
a ?oW rate sensor monitoring ?oW from the extraction outlet
indicates ?oW has dropped beloW a predetermined level.
[0040] According to a further aspect, the present invention
Where only a minimum sample volume is required,
provides a sampler for extracting sample volumes of substan
any pump capable of pumping against a vacuum at a knoWn
?oW rate may be employed. Utilisation of loW inertia pumps
tially single-phase ?uid or gas from a ?uid-?oW system con
With precisely controllable throughput enables the ?uid con
troller to start and stop the pump as often as required by
?uctuations in single-phase ?uid level in the collection recess
during the acquisition of the de?ned ?uid volume required for
sampling.
[0028]
In milk line sampling, the milk ?oW from the animal
is maintained by a vacuum applied to the milk line. Conse
quently, a further function of the ?uid controller and pump is
to seal the ?uid extraction outlet from the effects of the
vacuum during and after collection of the samples.
[0029]
In one embodiment, the ?uid sensor is con?gured as
taining multi-phase ?uids, said sampler including;
[0041]
a collection recess adapted to separate substan
tially single-phase ?uid from said multi-phase ?uid;
[0042] an extraction outlet in said collection recess;
[0043] at least one ?uid sensor system capable of sensing
the presence and/or state of said single-phase ?uid or
gas, at a predetermined level in the collection recess,
[0044]
a ?uid controller capable of controlling ?uid or
gas ?oW from the collection recess via said extraction
outlet;
characterised in that said ?uid sensor system includes
a simple ?uid level detector, preferably positioned to detect
at least tWo distinct sensors respectively capable of utilising
the presence of single-phase ?uid at a position in the collec
tion recess indicative of su?icient single-phase ?uid volume
to extract said de?ned volume sample.
distinct properties of the ?uid or gas to determine the presence
and/or state of the sample volume present in the collection
recess.
detectors may be employed to provide data on ?uid level
[0045] According to a yet further embodiment of the
present invention, said properties of the ?uid or gas include
change and/or rate of ?uid level change. Thus, providing an
transmission/absorption, refractive index, re?ectance, back
[0030]
In alternative embodiments, additional ?uid level
additional ?uid sensor above the ?rst ?uid sensor provides
scattering, opacity, capacitance, inductance, conductivity,
advanced Warning to the ?uid controller that the ?uid level in
electrical resistance, dielectric constant, ultrasonic, magnetic
the collection recess is trending to fall beloW the level neces
sary to extract a de?ned volume sample. Where the sample
or acoustic.
volume contained in the extraction Well beloW the level detec
tor is very small, an indication of the rate of level change may
[0046] In a preferred embodiment, said ?uid sensor system
includes
be omitted Without affecting the functionality of the sampler.
[0031] Alternatively, the ?uid sensor may continuously
[0047] a total internal re?ection sensor including an
emitter and a detector, and
[0048] a transmission sensor including an emitter and a
measure the absolute single-phase ?uid level Within the
detector arranged on substantially opposing sides of the
extraction recess.
collection recess.
Oct. 28, 2010
US 2010/0273273 A1
[0049] Preferably the state of a sample volume determined
by the ?uid sensor system includes at least one of; single
distinctive outputs from sensing the sample volume in com
parison to sensing any other components of said multi-phase
phase ?uid, froth, or gas.
properties of the ?uid or gas permits the characteristics of the
?uid in the ?uid ?oW system.
[0054] According to a further aspect, the present invention
provides a method of con?guring a sampler as hereinbefore
sensors to be matched With the characteristics of the type
described, said method including the step of;
[0050]
The use of at least tWo sensors utilising different
sample volume desired for extraction and sampling.
[0051]
[0055] selecting said tWo or more sensors for the ?uid
sensor system such that sensing the presence and/ or state
By Way of example, in an embodiment such as a
typical milk line, the ?uid-?oW system may include milk
(single phase and froth), air, cleaning ?uid such as Wash
of a sample volume for subsequent extraction from the
collection recess produces a distinct out put from the
?uid sensor system sensors in comparison to sensing any
Water, or tap Water in addition to a ?lm or residue of tap Water,
Wash Water or milk Which may remain over the sensors in the
other components of said multi-phase ?uid in the ?uid
recess Walls after extraction of the sample volume. Table 1
below shoWs the outputs for different types of sensors With
the presence of the above mediums.
?oW system sensed in the collection recess.
[0056]
The present invention also provides a sampler
capable of intermittent extraction of a speci?c ?uid or gas or
TABLE 1
Sensor output With collection recess contents of
Wash
Tap
Method
Optical
Transmission
Optical Total
Internal
Re?ection
Optical
Backscatter
Capacitance
Wash
Water
Air
Tap Water
Water Film
Milk
Milk Film
Water
Film
O
O
O
l
O
O
0
0
l
0
l
0
l
0
0
0
0
l
0 or I
0
0
0
l
0
l
l
l
l
0
l
0
l
0
l
1
Zero
loW
very
loW
high
medium
very
high
medium
to
Impedance
Measurement
Capacitance
Charge
Transfer
Conductivity
high
[0052] It Will be appreciated that Where a sensor type outputs the same value for tWo different types of medium, a
second sensor may be chosen that exhibits a different
response to at least that medium to remove the measurement
a speci?c phase of ?uid/gas from a multi ?oW system, said
extraction being halted during periods When one or more
unWanted ?uid/gas phases are present in the collection recess.
Thus, the sampler may continually extract single phase milk
for example, yet cease extraction Whenever froth, air, clean
ambiguity. Optical transmission sensors can distinguish
betWeen air and single phase milk, but are unable to readily
distinguish betWeen air and tap Water or Wash ?uid. By adding
ing ?uid or Water are sensed in the collection recess.
a total internal re?ection sensor to the ?uid sensor system, it
after milk ?oW commences as the initial milk from a coW
can be seen from table 1, that the sampler is able to uniquely
possesses different properties from the main milk ?oW. Pref
erably, the sampler is capable of intermittent extraction of a
speci?c ?uid or gas or a speci?c phase of ?uid/gas from a
identity milk (the only combination With a (l, 1) sensor out
put, and is able to group tap Water/Wash Water, and air/tap
Water ?lm/milk ?lm/Wash Water ?lm. Typically, either tap
Water or Wash Water Would be used for cleaning purposes and
thus there is no need to distinguish betWeen each other. Simi
larly, a (0, 0) sensor output narroWs doWn to either air or a ?lm
or either milk or cleaning ?uid. Thus, by con?guring the
sampler to avoid the possibility of ?lms covering the sensors
(as described more fully beloW), the sampler can distinguish
[0057]
Sampling is preferably delayed for a short period
multi ?oW system, said extraction being halted during periods
When one or more unWanted ?uid/gas phases are present in
the collection recess.
[0058] In a further embodiment, extraction of the sample
volume may be delayed for a predetermined period after
optical transmission and a total internal re?ection sensor. It
can be readily seen that a number of permutations are pos
commencement of ?uid ?oW in the ?uid ?oW system.
[0059] Although the combination of a transmission sensor
and a total internal re?ection sensor offer complimentary
bene?ts, alternative sensor technologies also offer certain
characteristics Which may be desirable in certain applica
tions.
sible, dependant on the medium of interest and the nature of
the ?uid ?oW.
forms including impedance and charge transfer based capaci
[0053]
Thus, according to a further aspect of the present
tive sensing. Impedance based capacitance sensors consist
invention, said at least tWo distinct sensors are capable of
essentially of a pair of electrodes that form a capacitor With
betWeen air, single phase milk, and cleaning ?uid by using a
[0060]
Capacitance sensors are available in numerous
Oct. 28, 2010
US 2010/0273273 Al
the material to be sensed (i.e. the collection recess forming the
dielectric betWeen the plates. Different materials alter the
dielectric properties resulting in the detection of a different
capacitance. The capacitor may Work With an oscillator to
form a tuned circuit, and changes in the dielectric are detected
by changes in the operating frequency. Thus, in the present
invention, the electrode plates are placed either side of the
collection recess. Alterations in the ?uid, gas, or froth in the
The frequency may also be varied to provide further informa
tion on the medium present in the collection recess. HoWever,
the build up of residue on the probes may affect tWo probe
sensors, generating false readings. This may be overcome
using a 4-probe system Where one pair of probes maintains a
constant current and a second pair of high impedance probes
measures the voltage. This has the advantage of largely can
celling the effects of dirt build-up, as the voltage is only
quently altering the measured impedance.
measured by the high impedance probes Which are less
affected by residue build up. The probes still require carefully
[0061]
positioning as an empty collection recess With just a high
collection recess Would alter the dielectric constant conse
HoWever, although impedance based sensors oper
ate successfully for non-conductive ?uids, they can encounter
conductivity ?uid ?lm (e.g. acid-based Wash Water) present
dif?culties With conductive ?uids such as milk. Milk residue
forms tWo conductive plates inside the collection recess,
Which presents substantially the same impedance as a Well
full of milk.
can produce the same reading as a collection recess full of loW
conductivity ?uid (Water). Conductivity sensors can be used
to check for the presence of any type of ?uid in comparison to
a gas e.g. air. They can also distinguish betWeen Water, milk
[0062]
and Wash Water, except in the folloWing circumstances.
This dif?culty may be addressed by the use of
charge transfer capacitance sensors Which also use the same
physical arrangement of the electrodes on opposing sides of
[0067] Dilute Wash Water can display the same conductivity
as milk. Pure milk has a conductivity of 1-10 milliSiemens.
Pure Water has a loWer conductivity and Wash Water has a
the collection recess. The plates are charged With a voltage for
a short duration and then discharged through a measuring
circuit and the time measured for the voltage to decay to
determine the capacitance. The dielectric constant of the sub
stance in the collection recess can also be measured. By
mixtures of substances occur, e.g. tap Water With a very small
amount of residual Wash Water Will display the same conduc
tivity as milk. Such mixtures may easily arise in a rinse
careful control of the charging and discharging cycle, the
folloWing a Wash procedure.
effects of ?lm of milk residue are largely overcome.
[0063] Capacitance sensors are available in numerous
[0068] Wash Water is generally a mixture of tap Water and
either acid or alkali, Whereas tap Water is generally from a
forms including impedance and charge transfer based capaci
tive sensing. Impedance based capacitance sensors consist
farm bore or the like.
0069 A Wash P rocedure tyP icall y involves:
essentially of a pair of electrodes that form a capacitor With
the material to be sensed (i.e. the collection recess forming the
dielectric betWeen the plates. Different materials alter the
dielectric properties resulting in the detection of a different
capacitance. The capacitor may Work With an oscillator to
form a tuned circuit, and changes in the dielectric are detected
much higher conductivity. HoWever, ambiguity occurs When
[0070] coWs ?nish milking;
[0071] tap Water pushing milk through to the milk vat to
help avoid any milk remaining in the ?uid ?oW system
from being Wasted;
[0072] the milking system being isolated from milk vat;
[0073]
by changes in the operating frequency. Thus, in the present
invention, the electrode plates are placed either side of the
collection recess. Alterations in the ?uid, gas, or froth in the
collection recess Would alter the dielectric constant conse
quently altering the measured impedance.
[0064]
HoWever, although impedance based sensors oper
ate successfully for non-conductive ?uids, they can encounter
dif?culties With conductive ?uids such as milk. Milk residue
forms tWo conductive plates inside the collection recess,
Which presents substantially the same impedance as a Well
full of milk.
[0065]
This dif?culty may be addressed by the use of
charge transfer capacitance sensors Which also use the same
physical arrangement of the electrodes on opposing sides of
the collection recess. The plates are charged With a voltage for
a short duration and then discharged through a measuring
circuit and the time measured for the voltage to decay to
determine the capacitance. The dielectric constant of the sub
stance in the collection recess can also be measured. By
a cold rinse With tap Water to remove main milk
residue;
[0074] a hot Water and acid, or hot Water and alkali rinse
to remove milk ?lms, and
[0075]
a Water rinse to remove acid or alkali.
[0076] Consequently, it is possible for the collection recess
to contain;
[007 7 ] air
[0078] foam of milk and air
[0079] pure milk
[0080] pure Water
[0081] Wash Water
[0082] a mix of tap Water and milk
[0083] a mix of tap Water and Wash Water
[0084] The present invention provides a means to resolve
this uncertainty by the addition of a secondary sensor (eg a
transmission sensor) speci?cally selected to provide a distin
guishing response betWeen the mixtures and milk. Altema
tively, the sampler may receive information from an external
careful control of the charging and discharging cycle, the
source that a Wash cycle is in progress. This may provide a
effects of ?lm of milk residue are largely overcome.
[0066] Conductivity sensors may also be used to sense the
presence and/or state of a ?uid/gas in the collection recess,
partial means of overcoming this di?iculty in a sampler
already including tWo sensor types optimised to distinguish
though it does require the electrodes to be in contact With the
?uid/gas. In a simple conductivity sensor tWo probes are
positioned through opposing sides of the collection recess
type
betWeen different mediums Without the need for a third sensor
and the current ?oW betWeen them is measured to determine
the impedance of the medium in the collection recess. An
[0085] Charge-transfer based capacitive sensors can also
suffer from a comparable problem in that a small amount of
?uid With a high dielectric constant can give similar results to
a larger volume of ?uid With a loW dielectric constant. This
alternating current prevents electrolysis at the probe surfaces.
can be overcome by a collection recess con?gured With a
Oct. 28, 2010
US 2010/0273273 A1
small volume such that there is likely to be ?uid betWeen the
reference plates virtually continuously.
[0086]
The aforementioned sensor types are provide as an
illustration of the different ?uid sensor system con?gurations
possible and are not limiting. Optical transmission and total
internal re?ectance sensors have been found an effective
combination for milk line sampling and the present invention
is described further With respect to these tWo sensor types.
[0087]
In one embodiment, the total internal re?ection sen
sor and transmission sensor may use one of more common
emitters and/or detector.
[0088] In a preferred embodiment, each sensor includes an
individual emitter and a single detector common to both
sensors, Wherein the emitters are near infra red (NIR) LEDs
and the detector is a photo-diode.
[0089]
Preferably, the total internal re?ection and/or the
transmission sensor are/is located at said predetermined level
in the collection recess.
[0090]
Preferably, the total internal re?ection sensor emit
ter and detector are orientated toWards a common point on a
(With respect to an axis orthogonal to the boundary surface),
is governed by Snell’s laW Which states that:
111 sin 61:;12 sin 62
[0096] Although this relation applies to both external and
internal refraction, only internal refraction is germane to the
present invention.
[0097] If the incident ray is in a medium of higher refractive
index (ni>n2) than the secondary medium, the exit ray is
refracted toWards the boundary. Total internal re?ection
occurs When 61:66 (the ‘critical’ angle), With nl sin 66:11,, so
that Elc:sin_l (n2/nl).
[0098] When 6966, Snell’s laW cannot be satis?ed and
instead of being refracted, the incident ray is totally re?ected
off the boundary surface. In the present invention, the total
internal refection sensor is positioned such that one of the
Walls of the collection recess acts as the re?ective boundary
surface, With the emitter and detector components set into the
Wall material itself. By mounting the emitter and detector at
45° to the axis orthogonal to the boundary surface, then air is
present in the collection recess (i.e. n2:l) and if nl>\/2 then
Wall of the collection recess and positioned substantially
symmetrically either side of an axis orthogonal to the Wall and
6c<45o [i.e. 6c:sin_l((n1>\/2)/l):<45];
passing through said common point.
totally re?ected.
[0091] In a further aspect of the present invention, the ?uid
controller incorporates a processor capable of receiving out
put signals from both the total internal re?ection sensor and
the transmission sensor and comparing said outputs With
predetermined reference data to determine Whether single
phase ?uid, froth, or gas is present in the collection recess.
[0092] It has been determined that the presence of single
phase ?uid (e.g. milk or Water), froth (e.g. milk and air
[0100] In the case Where the medium is Water or milk, 112 #1,
some of the light is refracted into the collection recess and the
[0099]
Since 61:49, 61>6C the incident emitter ray is
light intensities received by the detector are consequently
reduced. These measured values may then be used in com
parison With the corresponding values obtained With the
transmission sensor to establish said unique reference data
records denoting each of the three phases. The phase of the
substance in the recess may thus be determined by compari
bubbles), or as (eg air) produces speci?c readings from the
son of the measured values With the reference data record
total internal re?ection sensor and transmission sensor
values from both sensor types for each phase.
[0101] Preferably, said ?uid sensor system further includes
enabling the compilation of said reference data records
indicative of the substance state. Thus, the ?uid sensor system
measurements obtained from sample volumes of substance
from the ?uid-?oW system are compared With said data
records to determine the corresponding state of the sub stance.
[0093] The need for both the transmission and total internal
re?ection sensors is due to non-linearity in the response of
an analogue and digital controllers, said analogue controller
capable of processing output signals from said detectors and
providing an input signal to said emitters, said digital con
troller incorporates said processor and interfaces With the
analogue controller to receive, process and convert the ana
logue signals into equivalent digital signals, before the pro
milk (as described beloW), though it Will be appreciated that
cessor compares the detectors outputs With said data records
sampling of other ?uid types may dispense With the need for
to determination, the state of the substance. Preferably, the
processor outputs a signal to a display indicating the phase of
the medium in the sample recess. If a speci?c medium is
one of the sensors.
[0094]
The transmission of light through a medium varies
due to both the refractive index and the chemical bonds
present, due to the atoms absorbing the lights energy as it
passes through the medium. Light transmission is also Wave
required for sampling, e.g. single phase milk, the processor
length dependent. Therefore, by measuring the intensity of
detected.
[0102] As both sensors operate on optical principals, varia
tions in the ambient light level may cause inaccuracies. This
light passing through a medium an indication of its compo
sition may be established. The values speci?c to that medium
may then be used to identity that medium in situations Where
multiple mediums, may be ?oWing in the same line. HoWever,
operates a pump to alloW ?uid to ?oW through the extraction
outlet for a predetermined period after single phase milk has
is addressed by selectively sWitching the emitters, so that the
ambient light received by the detector is measured With all the
it has been found that milk does not exhibit a linear progres
emitters sWitched off. This value is then subtracted from the
sion in absorption betWeen the three mediums (i.e. single
phase, froth and air), primarily due to the variation in milk
detector output signal When measuring the emitter signals
solids. Consequently, an additional sensing means (i.e. the
total internal re?ection sensor) is utilised to distinguish
betWeen the mediums.
[0103] Thus, according to one aspect of the present inven
tion, the detector output measured With all emitter sWitched
[0095]
transmission emitter or total internal re?ection emitter is on.
The total internal re?ection sensor operates on Well
from the both sensors.
off is subtracted from the detector outputs measured When a
established optical principles. At a planar boundary betWeen
According to one aspect of the present invention, upon detec
tWo media With refractive indices nl and 112 the relation
tion by the ?uid sensor of the absence of said ?uid or gas, the
?uid controller may activate said pump or valve to alloW the
betWeen the angles of refraction and incidence, 61 and 62
Oct. 28, 2010
US 2010/0273273 A1
buffer between single ?uid samples.
tion from the ?uid extraction outlet. Preferably, a said addi
tional ?uid sensor is located in said storage vessel.
[0104] A further bene?t of using both a transmissive and a
total internal re?ection sensor is in determining the opacity of
additional ?uid sensor may also determine or con?rm
passage of non-dissolved gas to form a substantially non-?uid
the substance in the collection recess. This may be useful in a
variety of applications such as When sampling non-milk ?u
ids and also When ?ushing a sampling system With a cleaning
?uid such as Water. In milk-line sampling operations, a clean
ing ?ush may be performed betWeen individual samples, or at
the end of a batch of sampling, or at any other chosen point
desired by the operator. Clearly, it is desirable for the system
to determine What substance is in the collection recess to
identify When;
[0105]
[0106]
sampling may resume again,
all traces of the previous sample has been ?ushed,
[0107] a ?lm of the sample remains over the Walls in any
otherWise empty collection recess.
[0108] In addition to the above identi?cation capabilities, a
measure of the opacity enables the sampler to trigger certain
events such as Wash cycles for doWn stream processing units.
Thus, according to a preferred embodiment, the present
invention the opacity of any ?uid in the collection recess is
determined by the ?uid sensor system by comparison of the
?uid sensor system detector output With said data records to
identify the presence of single phase milk, Water, cleaning
?uid, or a combination of same.
[0109]
The detection of the absence of said ?uid by the ?uid
sensor may also be used to instigate an evacuation of the
sampler (for cleaning or the like) by pumping undissolved gas
or a cleaning ?uid through any sampler ?uid paths.
[0110] The possibility of a residual thin ?lm of ?uid Which
remains over the detectors after a milk slug has passed can
cause measurement errors. This possibility maybe attenuated
in a circular cross-section conduit ?uid-?oW system (such as
a typical milk line) by placing the entrance to the collection
recess slightly above the loWermost point of the conduit. This
effectively provides a small lip Which collects residual small
?uid deposits and prevents them running over the sensors in
the collection recess Walls. One simple method of achieving
this con?guration is by rotating the conduit about its longitu
dinal axis until the collection recess is located at approxi
mately 45° from a position at the loWermost point of the
conduit. Alternatively, a small rim may be formed about the
[0115]
Thus, the ?uid controller receiving input from the
Whether the single-phase sample ?uid Was present in the
storage vessel. Knowledge of the storage vessel volume
Would permit a further or independent means of verifying the
absolute or minimum ?uid sample volume. This reduces the
need for an accurate knoWledge of the ?uid ?oW rate through
the pump or valve controlled by the ?uid controller.
[0116] In a yet further embodiment, the storage vessel may
be dispensed With altogether and the conduits themselves
used to retain the extracted sample volumes prior to testing at
the sample processor. This confers several advantages includ
ing the cost saving in omitting the storage chamber and the
ease of use and cleaning. Nevertheless, it is necessary to
ensure the separate samples are discernable from each other
and are prevented from cross-contaminating each other. The
necessary separation may be provided by pumping gas (pref
erably air) betWeen successive samples to provide a segment
ing buffer.
[0117] Thus, according to a further embodiment, the sam
pler system is capable of pumping a gas volume betWeen
successive extracted samples to form gas buffers. Preferably,
said extracted sample volumes are temporarily storable in
?uid path conduits connected to said extraction outlet. In
milking applications, it may be desirable to monitor the milk
quality from each animal individually and even from each
teat.
[0118] In alternative applications (such as the petrochemi
cal ?elds) Where a gas forms the desired sample volume,
small ?uid buffers may be used to segregate successive gas
sample volumes.
[0119] The sample processor may be con?gured to perform
a variety of tests on the sample ?uid such as (in the case of
milk sampling) mastitis, lactate or progesterone detection/
monitoring.
[0120] Currently, mastitis is detected in a number of Ways
including initial detection by the farmer of clots on the milk
?lter. This can indicate to the farmer that there is mastitis in
the herd. Naturally, this method of detection cannot prevent
contamination of the milk vat for that milking day. HoWever,
the farmer can be alerted to check every teat in his/her herd,
either by visually assessing if there is infection and/ or squirt
collection recess entrance.
ing milk from the teat onto the milking shed ?oor to determine
[0111] The acquisition of an accurately measured volume
of single-phase sample ?uid may be desirable in a range of
applications aside from testing milk obtained from milk lines.
if there are clots therein.
Further reference to the use of the present invention in milk
line sampling should be understood to be exemplary and not
limiting.
[0112] After acquisition, the sample ?uidmay be processed
by a number of techniques according to the particular ?uid
characteristic or constituent of interest.
[0113] According to one embodiment, the de?ned ?uid
volume extracted may be temporarily retained in a storage
vessel before transportation to a sample processor. In a further
[0121] Another method used to detect mastitis is somatic
cell counts. This normally involves taking a sample of milk
from the coW and then sending the sample to a laboratory to be
tested in a specialised and expensive cell counter machine.
[0122] This test has the advantage of good results in detect
ing sub-clinical mastitis, but has the disadvantage in that the
test is only undertaken at intervals usually of at least one
Week. In NeW Zealand, routine somatic cell counts are under
taken daily on a bulk milk sample from the milk vat. The
presence of mastitis in the herd can be detected by a sudden
increase in somatic cell concentrations but the farmer is then
embodiment, multiple ?uid samplers may be combined to
faced With the problem of ?nding the infected quarter(s) in the
extract a plurality of ?uid samples Which may be combined
herd.
together in a common storage vessel or stored in individual
storage vessels until subsequent testing at the sample proces
[0123] Consequently, detecting mastitis by an accurate
automated process undertaken concurrently With the milking
sor.
process offers numerous advantages.
[0114]
In a further embodiment, at least one additional ?uid
sensor is incorporated into the sampler at a doWnstream posi
[0124]
Thus, according to one embodiment, the present
invention further includes a sample processor for performing
Oct. 28, 2010
US 2010/0273273 A1
mastitis detection, said sample processor including; an inlet
[0146]
from one or more sample storage vessels; a mixing chamber,
With a reagent inlet and an outlet draining to a ?oW chamber.
controller according to a further preferred embodiment;
[0147] FIG. 10a-b) shoW a schematic diagram of a back
scattering sensor according to a further preferred embodi
ment;
[0148] FIG. 11a-b) shoW a schematic diagram ofa capaci
[0125]
In an alternative embodiment, said sample storage
vessels are ?uid conduits.
[0126]
The present invention further provides a testing
method to aid in the detection of mastitis using the sampler as
hereinbefore described, said method characterised by the
steps of:
[0127] sensing the presence of single-phase ?uid in the
FIG. 9 shoWs a schematic block diagram of a ?uid
tance sensor according to a further preferred embodiment,
and
[0149] FIG. 12a-b) shoW a schematic diagram of a conduc
tivity sensor according to a further preferred embodiment.
collection recess at a predetermined height;
[0128]
BEST MODES FOR CARRYING OUT THE
INVENTION
activating said pump for a predetermined period
to extract a de?ned or minimum volume of single-phase
?uid sample via the ?uid extraction outlet;
[0129] transporting the ?uid sample to the mixing cham
[0150] The ?gures shoW one embodiment of the present
invention of a sampler in the form of a milk line sampling
ber in said sample processor;
[0130] mixing a reagent With the ?uid sample to form a
system (1) comprised generally of a milk line (2) containing
multi-phase milk (3) ?oWing from a coW (not shoWn) under
gel;
vacuum (not shoWn), a ?uid collection recess in the form of a
[0131] obtaining an indication of somatic cell numbers
by measuring the time the gel needs to drain through a
sample Well (4), a ?uid sensor system in the form of ?uid
sensor (5) interfaced With a ?uid controller unit (6) and a
de?ned exit hole;
[0132] determining if the drain time exceed a predeter
pump (7) controlled by the ?uid controller unit (6) and located
mined threshold value or range of values.
in a ?uid ?oW path from the sample Well (4) via a ?uid
extraction outlet (8). The output of the pump (7) is tempo
[0133] In order to determine the presence of mastitis, the
above measurements are used in conjunction With historical
data, eg cell counts from previous milking, as part of a herd
management system. Increased drain times due to more vis
cous gel are caused by an increase in the number of somatic
cell numbers, itself an indicator of mastitis.
rarily retained in a storage vessel in the form of a conduit (9)
before introduction to a sample processor (10) also interfaced
With the ?uid controller unit (6). The output of further pumps
[0134]
(10).
In one embodiment, said viscosity measurement is
performed by monitoring the time taken to drain the gel
though a ?xed siZe outlet.
[0135]
In a further embodiment, one or more ?uid sample
(7) from additional corresponding milk line sample extrac
tion systems (1) may also be temporarily retained in a corre
sponding conduit (9) before analysis in the sample processor
[0151]
Although the current embodiment is described With
reference to use in a milk line_application, it Will be appre
ciated that alternative applications are possible and that the
(s) is/are temporarily stored in one or more sample storage
invention need not be so restricted.
vessel(s) before transportation to the sample processor.
[0152] Milk from a coW (not shoWn) is removed from each
individual quarter teat by means of an automated milking
[0136] It Will be appreciated that the above-described test
ing for mastitis is but one embodiment of the present inven
tion and alternative testing procedures may be performed on
the extracted ?uid sample.
BRIEF DESCRIPTION OF DRAWINGS
[0137]
Further aspects of the present invention Will become
apparent from the folloWing description Which is given by
Way of example only and With reference to the accompanying
draWings in Which:
[0138] FIG. 1 shoWs a schematic representation of a pre
ferred embodiment of the present invention of a ?uid sampler;
[0139] FIG. 2 shoWs a schematic representation of a four
quarter sampling unit;
[0140] FIG. 3 shoWs a schematic representation of the four
quarter sampling unit of FIG. 2 connected to a ?uid sample
processor;
[0141] FIG. 4 shoWs a further schematic representation of a
sampling unit connected to a ?uid sample processor;
[0142] FIG. 5 shoWs a cross-section side elevation through
a milk line and ?uid sampler;
[0143] FIG. 6 shoWs a plan vieW of a cross-section along
XX shoWn in FIG. 5;
[0144] FIG. 7 shoWs transmission sensor data for different
mediums according to a further preferred embodiment;
system and travels along the milk line (2) under the effects of
a pulse vacuum applied to the milk line (2). As an inherent
consequence of the pulse milking system and the innate vari
ability of the milk emanating from the animal, the milk also
combines entrained air and/or undissolved gas (predomi
nantly air) in a multi-phase milk ?oW (3). Consequently, it is
not possible to simply extract a portion of the milk ?oW due to
the uncertainty of the sample composition, i.e. the percentage
volume of milk liquid and air.
[0153] Consequently, the sample Well (4) is formed on the
loWer portion of the milk line and consists broadly of a
tapered side pro?le With an elongated pro?le aligned along
the longitudinal axis of the milk line and comparatively nar
roW in the lateral direction.
[0154] As multi-phase milk (3) ?oWing along the milk line
(2) passes over the sample Well (4), the single-phase portion
of the milk (11) (i.e. substantially homogenous milk Without
entrained air or other undissolved gasses) ?oWs into the
recess under the action of gravity. The ?uid sensor (5) posi
tioned at a predetermined point above the bottom of the
sample Well (4) is used to detect the presence of said single
phase milk (11) at the height of the ?uid sensor (5). It Will be
appreciated that the ?uid sensor (5) may be con?gured to
detect either the presence or the absence of ?uid Without
for different mediums according to a further preferred
affecting the functionality of the sampler (1). The ?uid con
troller (6) receives input from the ?uid sensor (5) and upon
detection of single-phase ?uid (11) at the height of the ?uid
embodiment;
sensor (5), activates the pump (7) to extract a de?ned volume
[0145]
FIG. 8 shoWs a total internal re?ection sensor data