GB2071982A - Improvements in or relating to milking machines - Google Patents

Abstract

This invention relates to milking apparatus and a method of mechanically milking an animal using said apparatus wherein milk is drawn into teat cups applied to an animal's teats, into a claw and then into a milk line connectable to a nipple 16 of the claw or container adjacent thereto, the method comprising the steps of applying a constant vacuum to a milk chamber 50 of the claw and milk chambers of the teat cup, whilst simultaneously applying a pulsating vacuum to a pulsation chamber 49 of the claw and a pulsation chamber of the teat cups, and providing vacuum equalisation means 48 interposed between the milk chamber 50 and pulsation chamber 49 of the claw and separating the chambers whereby the level of vacuum in the pulsation chamber of the teat cup is prevented from exceeding that within the milk chambers of the teat cup. <IMAGE>

Description

SPECIFICATION Improvements in or relating to milking apparatus This invention relates to mechanical milking apparatus.

Modern mechanical milking apparatus operate to remove milkfrom animals by the application of a vacuum at the teats of the animal when the teats are engaged in a teat cup, whilst a chamber surrounding the teat cup is subjected alternatively to a vacuum and then atmospheric air. Milk removed from the teats of an animal is transported via a claw to a milk line, or containers depending on the type of installation. Claws used in milking plant can be divided into two general groups, H-type claws or cluster-type claws and the present invention relates more parti cularly to the latter type.

The function of a claw is to collect milk from the teat cups and to convey the milk to a milk line or container and to connect the chambers surrounding the teat cups (teat cup pulsator chambers) to a source of alternating vacuum and atmospheric air which is applied to the teat cup pulsator chambers by mechanical and/or electrical pulsator valves of which there are various kinds known in the art.

It is generally accepted that for the sake of the health and comform of animals milked mechanically by apparatus operating on the aforesaid principle, that during the application of vacuum to the teat cup pulsator chambers this vacuum should not exceed the vacuum applied to the milk chamber of the teat cup, and pulsator valves which operate to achieve these desiderata are described in United Kingdom Patent Specification No. 1391508. One detracting feature of the pulsator valves is than an excess of air is admitted to the milk line of milking plant which gives rise to the disadvantage that frothing occurs within the milk line during the milking process.If the chamber of clawpieces can be separated into a milk vacuum chamber and a pulsator chamber whilst taking advantage of the equilisation of vacuum principle embodied in the pulsator valves described in the aforementioned specification then the frothing problem can be overcome.

Accordingly, it is an object of the present invention to provide a method of an apparatus for mechanically milking an animal which will go some way towards eliminating the aforesaid problem.

Further objects and advantages of the present invention will become apparent from the ensuing description.

According to a first aspect of the present invention there is provided a method of mechanically milking an animal where milk from animal teats is drawn into teat cups applied to the animals teats, into a claw and then into a milk line passing from the claw or container adjacent thereto, the method comprising the steps of applying a constant vacuum to a milk chamber of the claw and milk chambers of the teat cup whilst simultaneously applying a pulsating vacuum to a pulsation chamber of the claw and pulsation chamber of the teat cups, and providing vacuum equalising means interposed between the milk and pulsation chambers of the claw separating the chambers whereby the level of vacuum in the pulsation chamber of the teat cup is preculuded from exceeding that within the milk chambers of the teat cup.

According to a further aspect of the present invention there is provided a claw for a milking apparatus, comprising a body, defining a milk chamber and a pulsation chamber separated from the milk chamber by vacuum equalisation means, said milk chamber being communicable with teat cup milk chambers of an associated set of teat cups and with a first source of vacuum, and said pulsation chamber being communicable with teat cup pulsation chambers of an associated set of teat cups and with a second source of vacuum, the arrangement being such that in use, the level of vacuum in the pulsation chambers of the associated teat cups is precluded from exceeding that in the milk chambers of the teat cups.

According to yet a further aspect of the present invention, there is provided, in combination a claw for a milking apparatus and a pulsator valve said claw comprising a body defining a milk chamber and a pulsation chamber separated from the milk chamber by vacuum equalisation means said milk chamber being communicable with teat cup milk chambers of an associated set of teat cups and with a source of vacuum and said pulsation chamber being communicable with teat cup pulsation chambers of an associated set of teat cups and with a source of vacuum, and said pulsator valve comprising a dome chamber communicable with the pulsation chamber of the claw, a pulsator valve pulsation chamber communicable with the dome chamber and the claw bowl pulsation chamber.Wherein the said pulsator valve pulsation chamber is arranged to receive and/or release a pulsating vacuum to the pulsation chamber of the claw and the arrangement being such that in use the level of vacuum in the pulsation chambers of the associated teat cups is precluded from exceeding that in the milk chambers of the teat cups.

Aspects of the present invention will now be described with reference to the accompanying drawings in which; Figure 1 is a diagrammatic perspective view of a typical milking apparatus to which the present invention relates, and Figures 2, 2a and 2b are partial cross-sections of a claw, similar to that described in United Kingdom Patent Specification No. 1391508, illustrating the mode of action of a pulsator valve combined with the claw, and Figure 3 is a plan view of a claw in accordance with one embodiment of the present invention, and Figure 4 is a cross-section at IV:IV of the claw at Figure 3, and Figure 5 is a cross-section at V::V of the claw at Figures 3 and 4, and Figure 6 is a diagrammatic cross-section of a conventional claw as is known in the art but including modifications thereto in accordance with a second embodiment of the present invention.

With reference to the drawings, Figure 1 thereof is a perspective view of aspects of a typical milking plant as is known in the art where a cluster claw generally indicated by arrow 1 has connections to a plurality of teat cups each generally indicated by arrow 2. A milk line 3 is arranged to carry milk away from the claw 1.

The teat cups 2 each comprise an inner chamber 4 (hereinafter referred to as the teat cup milk chamber) surrounded by a coaxial second chamber 5 (hereinafter referred to as the teat cup pulsation chamber), and condiuts 6 and 7 are connected between the teat cup milk chamber 4 and the teat cup pulsation chambers 5 providing communication to the interior of the claw land for this purpose nipples 8 and 9 are provided on the claw body. Milk received via conduits 6 is delivered to the lower interior of the claw and travels from there out the claw 1 into milk line 3 during milking.

As aforesaid the conditions for milking an animal are that, with the animals teats (not shown) engaged with the teat cup milk chambers 4, a constant vacuum be applied to the teat cup milk chamber 4 whilst an alternating vacuum and atmospheric pressure (hereinafter referred to as the pulsating vacuum) causing the wall 10 of the teat cup to collapse onto the inner wall 1 0a and then withdraw are applied to the teat cup pulsating chambers 5.

The claw illustrated by Figured 1 of the drawings is the kind described in United Kingdom Patent Speciication No. 1391508. These claws embody a pulsator valve, and the operation of this valve during milking will now be described with reference to Figures 2, 2a and 2b which are partial cross-sections of the claw 1.

With reference to Figures 2, 2a and 2b, claw 1 comprises a claw bowl generally indicated by arrow 11 which can be split for cleaning and maintenance purposes about a flange 12 into a upper body portion 13 and a lower body portion 14. The flange 12 embodies a bayonet-type joint (not shown in the drawings) and on assembly sections of the flange 12 of the upper and lower body portions 13 and 14 can be interposed by a sealing ring 15. The lower body portion 14, is provided with an intergrallyformed nipple 16 to which milk line 3 can be connected and a plurality of integrally formed nipples 9 to which condiuts 6 (see figure 1) from the teat cups are connected, whilst the upper portion 13 is provided with integrally formed nipples 8 arranged to receive conduits 7 from the teat cups 2.

The upper body portion 13 also includes a centrally positioned and downwardly depending skirt 18.

Atop the upper body portion 13, a pulsator valve generally indicated by arrow 19 is positioned as shown and covered by a dome 20 which is arranged to engage on flange 21 of the upper body portion 13.

The function of the pulsator valve as illustrated herein and those described in United States Patent Specification No. 3810,443 is to initiate and control the pulsating vacuum supplied to the teat cup pulsation chambers 5 of the teat cups 2 whilst a constant source of vacuum is applied to the milk line 3.

A pulsation valve 19 as illustrated comprises a cup shaped bobbin housing 22 an upper flange 23 of which is locatable on flange 21 ofthe upper body portion 13 of the claw and arranged to be secured in that position when the dome 20 engages with the same flange and the lower end 24 of the bobbin housing 22 suitably engages with a lip at the top of skirt 18 of the upper body portion 13 of the claw bowl 11. In this position the bobbin housing 22 divides an upper pulsation chamber 25, however communication with the interior of the claw bowl can be effected via a plurality of apertures 26 in the wall of the bobbin housing 24. Furthermore, apertures 27 in the upper flange 23 of the bobbin housing 22 allow atmospheric air to enter a region between the bobbin housing 22 and the complimentary bobbin 28 for the valve.Atmospheric air is filtered prior to entry into the valve by a gauze filter 29 placed between the dome 20 and the upper flange 23 of the bobbin housing 22. Atmospheric air may enter apertures 27 after passing beneath the lower edge of the dome cap 20 and openings 30 in the flange 21 of the upper body portion 13 of the claw.

In one instance when bobbin 28 is at rest the upper lip 31 thereof engages with the lower edge 32 of the diaphragm 33 and an "0" ring 34 fixed to the upper extremeity of the stalk 35 of the bobbin seals against an adjacent shoulder 36 of the bobbin housing 22.

At the lower end of the bobbin 28 an annular rubber washer 37 is secured in the position shown by a split ring 38, and it is observed that the "rest" position for the bobbin 28 a gap exists between the upper edge of the washer 37 and an internal shoulder 39 of the bobbin housing 24 providing a communication between the upper pulsation chamber 25 and the interior of the claw. The lower end 38 of the bobbin 28 is provided with a bore 40 which allows the free passage of air.

The diaphragm 33 is engaged between coaxial upper and lower mounting sleeves 41 and 42 respectively. The lower mounting sleeve 42 is a Tee-section member having a bore 43 therein into which a pulsation rate adjuster 44 engages in a push fit. The pulsation rate adjuster 44 is provided with a single flute 45 therein such that air can pass down a bore 45a, defined by the flute 45 and the bore 43 from the dome 20 into the interior of the bobbin 28.

The pulsation rate of the valve 19 is adjusted by movement up or down of the pulsation rate adjuster 44 relative to the lower mounting sleeve 42 and a compression spring 46 located in the dome cap at one end and a stepped portion of the upper mounting sleeve 41 applies a continuous downward force to the diaphragm 33.

The pulsation valve operates to produce a pulsating vacuum to the teat cup pulsation chambers 5 of the teat cups as follows, reference being made in the first instance to Figure 2. In Figures 2, 2a and 2b, the free arrows are indicating air movements within the pulsator valve.

Assuming vacuum conditions in the upper pulsation chamber 25 and the teat cup pulsation chambers 5, the area 47 within the dome 20 is being vacuumised as air as drawn down through the bore 45, bobbin 28 into the claw bowl 11. When the vacuum in area 47 within the dome 20 is low (say 20 k.p.a.) air pressure which enters the valve via openings 30 and apertures 27 which has been applying an upward force on the diaphragm 33, will eventually overcome the downward bias of spring 46, causing the bobbin 28 and the diaphragm 33 to lift up braking the seal between the bobbin "0" ring 34 and the adjacent shoulder 36 of the bobbin housing 22.

The new situation is illustrated by Figure 2a of the drawings. Atmospheric air via openings 30 and apertures 27 passes under the bobbin "0" ring and into the upper pulsation chamber 25, and via nipples 8 into the teat cup pulsation chambers 5 causing a rise in pressure and the teat cup liner 10 (see figure 1) will begin to collapse. It is to be noted that during this phase rubber ring 37 prevents incoming air entering the claw bowl 11. When the vacuum level in the dome 20 is lower (say 35 k.p.a.) air pressure acting on the underside of the diaphragm 33 will cause the diaphragm and the bobbin 28 to separate, this situation being illustrated by Figure 2b of the drawings. Atmospheric air will now flow into the dome interior 47 at the same time force the bobbin 28 downward until bobbin "0" ring 34 has sealed.

The new bobbin position allows air to be drawn via chamber 25 from the teat cup pulsation chambers until operating vacuum is reached. Air enters the claw bowl and creates a pressure difference between the vacuum source and the claw interior and milk and air will flow away via milk line 3. The spring bias and increasing air pressure in the dome will force the diaphragm 33 to reseal on the bobbin 28 and when this occurs the dome is again revacuumised and the cycle recommenced.

In a less specific aspect pulsator valves as described in relation to Figures 2, 2a and 2b, may be said to comprise a dome chamber (area 47 within dome 20) communicable with the claw bowl 11, a pulsator valve pulsation chamber 25 communicable with the claw bowl 11 and the dome chamber, wherein the pulsator valve pulsation chamber 25 is arranged to receive and/or release to the claw a pulsating vacuum. In one aspect of its operation one portion of the pulsator valve pulsation chamber 25 is vented to atmosphere via openings 30 and apertures 27 whilst in another aspect another portion of the chamber 25 is communicable (via nipples 8) with the teat cup pulsation chambers of a milking apparatus.

One disadvantage of these units is that more air is admitted to the air line than is desirable, causing frothing and milk fat globule damage in the riser to the milk pipe line, resulting in elevated levels of free fatty acids in the raw milk and consequent problems with the quality of stored manufactured produce.

In accordance with one embodiment of the present invention, modifications to a claw bowl of the kind described are provided to eliminate frothing of milk.

With reference to Figures 3,4 and 5 a vacuum equilising means such as diaphragm 48 replaces sealing ring 15 where the upper and lower portions 13 and 14 are joined having the effect of dividing the claw bowl 11 into a pulsation chamber 49 and a milk chamber 50. In addition, a further nipple 51 is formed in the side wall of the upper portion 13 of the claw 11 and surrounding the point of entry of the nipple 51 there is provided an orifice indicated by arrow 52 including a skirt 53 separating the pulsation chamber 49 to a main part and a sub-chamber 54 the arrangement being such that lower edge 55 of the skirt 53 is arranged to sealably engage the upper surface of the diaphragm 48 such than an air tight seal can be formed with the diaphragm 48. The diaphragm 48 may be of any suitable flexible material such as rubber or plastics.

In operation, when the vacuum level in the milk chamber 50 of the claw drops below that in subchamber 52, diaphragm 48 seals firmly against edge 55 of the skirt 53 and prevents further vacuumising of the chamber 49. Chamber 50 is connected to a source of continuous vacuum via nipple 16, and the arrangement is such that the vacuum to operate the pulsation valve 19 is obtained through the nipple 51 and atmospheric air from the pulsation chamber of the pulsation valve is exhausted to chamber 49.

When the vacuum level in chamber 49 falls below that in milk chamber 50, the diaphragm 48 is pulled downwards thus breaking the seal between the diaphragm 48 and the edte 55 of the skirt 53 allowing air to pass from chamber 49 to sub-chamber 54, and at the point where vacuum level in the chamber 49 returns to the same level as milk chamber 50, the diaphragm 48 seals against edge 55 of the skirt 53, preventing further vacuumisation of chamber 49 from the vacuum source fed into sub-chamber 52 via nipple 51.

Thus it will be seen that there is provided a means for continuous adjustment of the vacuum level in the pulsation chamber 49 of the claw to that of the milk chamber 50 of the claw.

Also it will be seen that the maximum vacuum in the pulsation chambers of associated teat cups will not exceed the vacuum in the interiors (milk chambers) of them as the vacuum in the milk chamber 50 of the claw is transmitted through nipples 9 and the associated condiuts to the teat cups. If the vacuum through nipples 9 falls below that applied through nipple 51 owing to the presence of milk in the milk line or the riser thereto then diaphragm 48 will be drawn upwardly to seat on edge 55 and air will be admitted through pulsator 19 to bring the maximum vacuum in chamber 49 and hence the teat cup pulsation chambers to be no greater than that in the milk chamber 50 and hence that in the milk line. To move milk away from milk chamber 50, an air admission hole 56 is provided.

With reference to Figure 6 of the drawings, a conventional claw as illustrated is divided into a lower milk chamber 58 and an upper pulsation chamber 57. Nipples 59 (of which there are four) will receive a short milk line from the milk chamber of a teat cup and nipple 60 is joined to a milk vacuum line of conventional type. Air admission means 61 of the minimum diameter (for example 1/32 inches) admits the air into the milk chamber of the claw to allow the passage of milk out of this chamber. Nipples 62 of which there are four) are designed to receive a short pulsation line joined to the pulsation chamber of a teat cup and nipple 63 is joined to a remote source of a pulsating vacuum and as with the previous embodiment an edge 64 of orifice 65 is designed to seat on diaphragm 66.

in operation, a vacuum at a substantially constant rate is applied to nipple 60 whilst a pulsating vacuum is applied to nipple 63. If the level of vacuum applied to nipple 63 exceeds the level within the chamber 58 then diaphragm 66 is seated against port edge 64 cutting off the vacuum and the level of vacuum in pulsation chamber 57 remains no greater than in the chamber 58. This equalisation of vacuum is transmitted through nipples 62 and 59 via the short lines to the respective pulsation and milk chambers of the teat cups and it will thus be seen that the advantages of limiting the maximum vacuum level in the pulsation chambers of the teat cups so that this level does not exceed the vacuum level in the milk chambers thereof, can be achieved when a conventional claw modified in accordance with a further embodiment of the present invention.

For both embodiments of the claw the vacuum source communicable with the milk chamber of the claw and the vacuum source communicable with the pulsation chamber of the claw are provided with separate connection from a main vacuum source (a vacuum tank). Alternatively, these vacuum sources to the claws may be fed from the same connection from the main source.

Aspects of the present invention have been described by way of example and it will be appreciated that modifications and additions thereto may be made without departing from the scope thereof and defined in the apending claims.

Claims (22)

1. A method of mechanically milking an animal where milk from animals teats is drawn into a teat cups applied to the animals teats into a claw and then into a milk line passing from the claw or container adjacent thereto, the method comprising the steps of applying a constant vacuum to a milk chamber of the claw and milk chambers of the teat cup, whilst simultaneously applying a pulsating vacuum to a pulsation chamber of the claw and a pulsation chamber of the teat cups, and providing vacuum equalisation means interposed between the milk and pulsation chambers of the claw separating the chambers whereby the level of vacuum in the pulsation chamber of the teat cup is precluded from exceeding that within the milk chambers of the teat cup.

2. A method of mechanically milking an animal as claimed in claim 1 where the vacuum equalisation means comprises a flexible diaphragm.

3. A method of mechanically milking an animal as claimed in claim 1 or claim 2 wherein the vacuum equalisation means is a rubber or plastics diaphragm.

4. A method of mechanically milking an animal as claimed in any one of claims 1 to 3 wherein the pulsating vacuum is delivered to the claw via an orifice sealable against the vacuum equalisation means.

5. A method of mechanically milking an animal as claimed in claim 4 wherein the orifice delivers a pulsation vacuum to central portion of the vacuum equalisation means.

6. A method of mechanically milking an animal as claimed in claim 4 wherein the orifice delivers pulsating vacuum to an area at or near the periphery of the vacuum equalisation means.

7. A claw for milking apparatus, comprising a body, defining a milk chamber and a pulsation chamber separated from the milk chamber by vacuum equalisation means, said milk chamber being communicable with teat cup milk chambers of an associated set of teat cups and with a source of vacuum, and said pulsation chamber being communicable with teat cup pulsation chambers of an associated set of teat cups and with a source of vacuum, the arrangement being such that in use the level of vacuum in the pulsation chambers of the associated teat cups is precluded from exceeding that in the milk chambers of the teat cups.

8. Aclawfora milking apparatus wherein as claimed in claim 7, the body defining the milk chamber thereof is provided with at least one air admission hole.

9. A claw for milking apparatus as claimed in claim 7 or 8, wherein the said vacuum equalisation means is a flexible diaphragm.

10. A claw for a milking apparatus as claimed in any one of claim 7 to 9 wherein the vacuum equalisation means is a rubber diaphragm.

11. A claw for a milking apparatus as claimed in any one of claims 7 to 10 wherein the pulsating vacuum delivered to the pulsation chamber of the claw via an orifice sealable against the vacuum equalisation means.

12. A claw for a milking apparatus as claimed in claim 11, wherein the orifice delivers a pulsating vacuum to a central portion of the vacuum equalisation means.

13. Aclawfora milking apparatus as claimed in claim 11, wherein the orifice delivers a pulsating vacuum to an area at or near the periphery of the vacuum equalisation means.

14. Aclawfora milking apparatus as claimed in claim 13, wherein the orifice comprises a skirt intergrally formed with the wall of the claw defining a sub-chamber within the pulsation chamber and a nipple formed in the wall of the claw and leading into the sub-chamber.

15. A claw for a milking apparatus as claimed in any one of claims 7 to 14 wherein the vacuum source communicable with the milk chamber of the claw and the vacuum source communicable with the pulsator chamber of the claw are provided with separate connections from a main vacuum source.

16. A claw for a milking apparatus as claimed in any one of claims 7 to 14 wherein the vacuum source communicable with the milk chamber of the claw and the vacuum source communicable with the pulsation chamber of the claw are fed from the same connection from a main vacuum source.

17. In combination, a claw for milking apparatus and a pulsator valve said claw comprising a body defining a milk chamber and a pulsation chamber separated from the milk chamber by vacuum equalisation means said milk chamber being communicable with teat cup milk chambers of an associated set of teat cups and with a source of vacuum and said pulsation chamber being communicable with teat cup pulsation chambers of an associated set of teat cups and with a source of vacuum, and said pulsator valve comprising a dome chamber comminicable with the pulsation chamber of the claw, a pulsator valve pulsation chamber communicable with the dome chamber and the claw bowl pulsation chamber.Wherein the said pulsator valve pulsation chamber is arranged to receive and/or release a pulsating vacuum to the pulsation chamber of the claw and the arrangement being such that in use the level of vacuum in the pulsation chambers of the associated teat cups is precluded from exceeding that in the milk chambers of the teat cups.

18. The combination of claim 17, wherein the pulsator valve pulsation chamber is provided with one portion vented to atmosphere and another portion communicable with the pulsation chambers of the teat cups of a milking apparatus.

19. A claw for a milking apparatus as claimed in any one of claims 7 to 16 in combination with a pulsator valve substantially as herein described with reference to the Figures 2, 2a and 2b of the accompanying drawings.

20. A claw for a milking apparatus substantially as herein described with reference to Figures 3,4 and 5 of the accompanying drawings.

21. A claw for a milking apparatus substantially as herein described with reference to Figure 6 of the accompanying drawings.

22. A method substantially as hereinbefore described with reference to the accompanying drawinas.