Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
w o 93/01709 2 i 1 a , 3 7 PCT/C sg2/01311
MILKING MACHINE CLA~PIECE
The present invention relates to a milking machine clawpiece
for use in automatic milking apparatus.
The basic components of a milking installation, at least as
far as the present invention is concerned, are (1) a cluster of
four teat cups including (2) a clawpiece, (3~ a suction pump
and (4) a pulsator. Each teat ~up contains an annular pulsation
chamber defined between a rigid outer casing of the cup and a
flexible inner l~ner which fits over one of the cow's teats.
In use, a steady pressure of approximately 50 kPa below
atmosphere is continuously applied to the "core~ space enclosed
by the liner. Apart from encouraging a flow of milk into the
core space, this negative pressure is also effective to clamp the
teat liner on to the teat - this being referred to as "adhesion".
The pressure applied by the pulsator to the annular pulsation
chamber, however, alternates between a first pulsation value
of 50 kPa below atmospheric pressure and a second pulsation value
of atmospheric pressure.
At the first pulsation value, there is zero differential
across the liner, and milk is sucked from the teat into the core
space. From the core space the m71k ~s drawn down a flexible
"short milk" tube into one of the four tubular inlet "nipples"
projecting upwardly from the interior volume of a special
junction called a "cla~piece". From the clawpiece the milk is
; drawn through an outlet nipple and v~a a "long milk" tube to an
appropriate receptacle or pipeline. The other three nipples of
the clawpiece are connected to similar teat cups and thence to
Ithe other teats of the cow's udder.
At the second pulsation alue, the liner collapses on the
teat and the pressure applied by it to the teat causes cessation
of milk flow and provides a necessary massage of the teat.
During normil operation. the pulsation pressure switches from
one value to the other, with a cycle frequency which is typically
once every second, giving rise to a correspondingly intermittent
flow of milk.
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According to a first aspect of the present invention, a
milking machine clawpiece comprises a pulsation distribution
chamber which is isolated from the milk-carrying cavity of the
clawpiece by the diaphragm or like-operating device of a valve
assembly for the clawpiece inlet nipples whereby, in operation,
when the pulsation d~stribution chamber is evacuated to open the
liners and allow milk to flow from the teats into the short milk
tubes, the pressure difference across the diaphragm or
like-operating dev~ce holds the valve assembly in a first
pos~t~on to close the clawp~ece valves when the pressure in the
cla~piece cav~ty exceeds that ~n the associated inlet ntpples and
milk from the teats flows only as far as the closed clawpiece
valves, whereas when the pulsation distribution chamber is at
atmospheric pressure to close the liners and prevent milk flow
from th~ teats, the pressure difference across the diaphragm or
like-operat1ng dev ke holds the valve assembly in a second
posiff on to open the clawpiece valves and allow milk previously
collected in ~the short milk tubes upstream of the closed
cla~piece valves to discharge into the clawpiece cavity for
removal v~a the clawpiece outlet nipple into the long milk tube.
The term like-operating device~ is to be ~nterpreted as
including any mean~ (other than a diaphragm) wh~ch is responsive
-~to a pressure differential between the clawpiece puTsation
distri~but~on chamber and cavity, to move the valve assembly
~between first and -second valve operating positions as above
~ .describéd. One~s~uch~means would comprise a piston, for example.
- Conven~ently, the valve assembly is vertically displaceable
between an uppér ft~rst position aod a lower second pos~tion.
, i Convenie,ntly, the valve assembly includes an external part by
means of which the~valve assembly can ~be moved to close the
clawpi~e~ce valves irrespective of the operating conditions within
-
the c~awpiece. Such movement might be effected manually, for
example,~ or by a conventional automatic closter removal
attathment.
,
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Alternatively (or additionally), the clawpiece includes an
external part which can be moved to shut off the normal supply
route of pulsating vacuum supply to the pulsation distribution
chamber and control means are provided to control an alternative
supply route for the pulsating vacuum supply so as to isolate the
pulsation distribution chamber from the atmospheric pressure
component of this supply. As before, the required movement of
the external part may be effected manually, for example. or by a
conventional automatic cluster removal attachment.
Conveniently, the clawpiece valves have at least a degree of
independence from one another so that, when the valve assembly is
in the first posi ff on, one or more of the valves can open in
response to an appropriate pressure differential across the valve
or valves while the remaining valves or valve remain closed.
lS Thus in one such case, the valve assembly is made of rubber
or other resilient material and comprises an upper diaphragm
portion which is linked by a stem to a depending skirt portion
div~ded into four separate flap sections serving as the
individual clawpiece valves.
According to a second aspect, the invention comprises a valve
~; ~ assembly as described in the preceding paragraph.
- Qccording to a third ~aspect, the invention comprises a
milking installation includ~ng one or more clawpieces according
to the first aspect of the invention.
In conventional milking machines, as used for the last sixty
~ years or so, ~ small a~r bleed ~s provided in the clawp1ece or in
-~ ~ -the short milk tubes to assist the transport of milk from the
milking cluster to the receptacle or pipeline. This first method
of milking is referred to as conventional milking.
~, i !
More recently, it has been proposed to control udder disease
by using one-w~y valves within the liner, within the short milk
tubes. or within the clawpiece to prevent flow back of milk
towards the teat. When operated without airbleeds, the teat
liners in such cases are -substantially sealed, during milking,
from any supply of air to the milk-carrying core regions of the
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teat liners. Teat liners sealed in this way are referred to as
pneumatically-isolated teat liners and the new second method of
mi lking produced, which has certain performance advantages over
conventional milking, is referred to as hydraulic milking.
S UKPA Publication No. 2244417 A (National Research Development
Corporation) proposes a method of automatic milking in which,
during the main milking period. the teat liners are substantially
sealed from any supply of air to the milk-carrying core regions
of the teat liners whereas during the closing stages of milklng,
air is automatically admitted to said regions to provide
conventional milking. This third method of milking is referred
to as dual regime milking.
The clawpiece of the present invention has application in a11
three methods of milking outlined above but it is possibly at its
most advantageous when used in a dual regime system.
An embodiment o~ the invenff on will now be descr1bed, by way
of example only, with reference to the accompanying drawings, in
which:
Figure 1 shows a simplified and somewhat diagrammat k view of
part of a typical milking installation utilis~ng clawpieces
according to the present invenff on;
~ Figure 2 shows a somewhat diagra _ at k vert k al sect~on of a
clawpiece for use in the installation of Figure l;
Figure 3 shows the same clawpiece as Figure 2 at a different
stage of its operation;
Figures 4a and 4b (collectively referred as Figure 4)
respectively show a cross-section and perspective view of a valve
assembly~for use in the clawpiece of Figures 2 and 3; and
, Figure $ shows a modification of the clawpiece of Figures 2
and 3.
-~ The same reference numerals have been used for the same or
- functionally s~imilar items in the different Figures.
Thus referring first to Figure 1, this Figure shows, by way
of illustration, only two milking units 8 although in practice
there wilt typ~cally be ten or so such units in an average-sized
milking installation.
w o 93/01709 2 1 1 ~ ~ ~ 7 PCT/CB92/01311
Each unit 8 consists basically of four teat cups 10, a
clawpiece 12, four short milk tubes 14 connecting the teat cups
to the clawpiece, and a long milk tube 16 taking the milk from
the clawpiece to a recorder jar 18 (or other milk measuring
device).
Milk flow away from the teats, but not in the reverse
direction, ~s allowed by one-way milk flow va)ves ~not shown).
In hydraul k and dual ~reg~me milking systems, the
convent~onal a~r-bleeds upstream of these one-way milk flow
valves are om~tted so that during normal operation, the
installation w~ll prov~de hydraul1c milking. For further details
of spec~f1c examples of these valves. and of hydraul k and dual
regime m~lking ~n general, reference should' be made to British
Patent No. 21S9685 B (National Research Development Corporation)
and UKPA Publ1caff on No. 2244417 A (National Research Development
Corporaff on).
Return~ng no~ to F~gure 1, it will be seen that the bottoms
of the recorder ~ars 18'are connected to a common m~lk conveyance
pipeline 20 although in an alternative embodiment (not shown),
the ~ars 18 (or equ~valent) are omitted and the lohg milk
tubes 16 lead d~rectly to~tbe co D n milk conveyance pipeline 20.
Refer~nce numeral 22 indicates the milking vacuum pipeline
while reference numeral 24 ind~cates the air line for the
~: :
~-~ - pulsator 26.
As shown, the comm~n milk conveyance pipeline 20 leads to a
. receiver~v~essel 28~and in operat~on of the installation. a m~lk
pump- 30 -operates to ~discharge milk from the vessel 28, via
~'~ 'p'ipeline 32, to a bulk~tank (not shown).
, ~ The installation further includes the usual sanitary trap 34,
vacuum regulator 35.~i~nterceptor 36 and vacuum pump 37.
- Turning now to Figure 2. this shows one of the clawpieces 12
; 'for~use in~ the milking installation of Figure l~
The c!awpiece comprises a pulsation distribution chamber 40
which is isolated from the mi~lk-carryi~ng cavity 42 of the
-' 35 clawpiece by the dtaphragm portion 44 of. a vertically
.
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displaceable valve assembly 46 for the four clawpiece inlet
nipples 48. Reference numeral 49 indicates the usual pulsating
vacuum supply inlet to chamber 40.
The assembly 46 (see also Figure 4) is made of rubber, or
other resilient material, and comprises a depending skirt portion
joined to the diaphragm portion by a stem 50. The skirt portion
is d~v~ded into four separate flap sections 52 serv~ng as the
ind~vidual clawp~ece valves, each of wh~ch is able to remain
closed ~ndependently of the others in the event that a continuous
vacuum ~s present ~n the associated 1nlet n~pple 48 e.g. due to
the cessat~on of milk flow from the relevant teat.
As shown 1n F~gure 2. the upward travel of the d~aphragm
portion 44 is limited by downwardly projectlng stop portions 54
wh k h surround an externally projecff ng pull 56. An upward
movement of the pull w~ll ra~se the assembly 46 to close the
valves, whatever the opera ff onal condltions, within the
cla~piece. Pull S6 may be dtsplaced manually or by a
convent1Onal automatic cluster removal attachment at the end of
m~lktng.
F~gure ~ sho~s an alternaff ve arrangement in which the pull
(58) operate; instead to shut off the normal pulsating vacuum
supply route to the chamber 40 whtch is thereafter isolated from
the atmospher~c pressure component of th~s supply by a one-way
valve 59.
In another alternative arrangement ~not shown), the shut-off
~ arrangements of figures 2 and 5 are comblned so that lifting the
;~ pull both closes the clawp~ece valves 52 and shuts off the normal
vacuum supply route to~chamber 40 wh1ch continues to be evacuated
,via the one-way valve S9.
Inst~ead. or (in the case of the two alternative arran~ements
descr~bed ?bove> additionally, the vacuum~supply to the milking
units .8 can be shut off at the end of milking by any convenient
means e.g. a conventional shut off valve located in the long milk
tube to the un~t or between the vacuum supply tube 22 and the
associated recorder jar 18 for the unit.
WO 93/01709 2 ~ 1 0 ~ 0 7 PCl`/GB92/01311
Figure 2 illustrates the valve assembly 46 as it will appear
when chamber 40 is evacuated and the valves 52 close to prevent
the flow o~ milk from the short milk tubes ~via nipples 48) into
the cavity 42 whenever the pressure in the clawpiece cavity
S exceeds that in the associated inlet nipples. Figure 3, on the
other hand, illustrates the situation where the pulsation
distribution chamber is at atmospheric pressure and the
assembly 46 has been displaced downwardly to open the valves 52
and allow milk to flow lnto cavity 42 for passage, via outlet
nipple 60, into the long milk tube.
Pulsating the liner on the teat provides necessary massage to
encourage blood circulation in the teat and avoid damage to the
teat tissue. Pulsation also provides relief for the musculative
tissue surrounding the teat orifice necessary to maintain the
integrity of the streak canal and its function of preventing
invasion by pathoqenic organisms. Malfunction of pulsat1On to
the teat is known to cause teat end damage and increased
pathogenic penetrat~on into the udder.
Nevertheless. in conventional milking clusters. pulsation
also disturbs the flow of milk from the teat cups and can cause
impacts on the teat end wh kh aid penetration of pathogen through
the streak canal and into the udder.
Pathogenic invasion through the streak canal of the teat
invariably results in disease (commonly called mastitis).
In a fourth aspect. the present invention relates to a method
of milking which combines the use of valves which control milk
flow in the clawpiece of the milking machine cluster and air flow
into the mouthpiete of the teat cup liner, and themselves are
controlled by the pu1sation system of the milking cluster.
Pulsation controlled air flow valves for the mouthpiece are the
subject of a previous patent application Publication No.
GB 2244417 A
According to this fourth aspect, the present invention is a
milking method which uses this type of air flow valve in
combination with a new mechanism controlled by pulsation and
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organises the direction of milk flow from the teat cups into the
clawpiece chamber.
Typically, when used in conjunction with the systems of UKPA
Publication No. 2244471 A, the new method of milking functions as
S now described. When vacuum is applied to the outside of the
liner, it also closes the air valve at the mouthpiece of the
liner and the valves between the teat cup and the clawpiece.
When the milking cluster is first applied, teat barrel adhesion
is established and then the air valve only serves to maintain the
mouthp~ece pressure at atmosphere each ff me atmosphere is applied
to the pulsation chamber. It continues this function until the
late stages of milking when teat barrel fr ktion is lost with the
liner. and air drives out the milk in the teat cup each time the
liner is collapsed and the pulsation chamber is at atmosphere.
lS During the whole of milking, however. the milk valves are opening
and closing (in sympathy with pulsation pressure~, being closed
wh~lst the l~ner is opening and be~ng open when the liner is in
the closed position. M~lk only flows past them if the clawpiece
pressure is lower than that in the teat cup. When the pulsation
pressure changes to atmosphere, the milk valves open while the
liner collapses and expels the milk collected du.ing the liner
open phase (vacuum phase). By these means milk is encouraged to
flow only in one direction away from the teat thus avolding the
problems caused by multi~ directional milk flow in the
conventional milk~ng machines. Machine induced i-nfection is
tontrolled and the milk receives less damage during transport
(less l~polysis) in the machine.
Hydraulic milking methods function in the following manner
and have several disadvantages. Basically the hydraulic milking
method used only milk flow valves with no air admission. In
- hydraulic milking the gravity-closed valves operate independently
of -pulsation and respond only to the changes of pressure of the
- teat cup in relation to pressure in the clawpiece. At the end o~
¦ milking a special arrangement is made to introduce air into each
mouthpSece simultaneously to unclamp the teats from the liner.
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w O 93/01709 2 1 i 0 à ~ 7 PCT/GB92/01311
The main physical disadvantages of hydraulic milking are 1)
mouthpiece vacuum can be uncomfortably high and 2) the
independent valves can, especially in low or air flow periods of
milking, collapse the liner tightly on the teat end without
relief.
The present invention according to said fourth aspect as
above discussed, ls deslgned to overcome these particular
disadvantages so that the beneficial aspects of controlled flow
can be achleved without detr~ment.
