GB1592408A

GB1592408A - Method and apparatus for milking

Info

Publication number: GB1592408A
Application number: GB3981477A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-10-14
Filing date: 1977-09-23
Publication date: 1981-07-08
Also published as: AU2883677A; CA1075632A; DE2746310A1; NZ185091A; AU516844B2; IE45586B1; NL7711267A; IE45586L; DK458577A

Description

(54) METHOD AND APPARATUS FOR MILKING (71) I, JOHN HOUGHAM ABRAHAM SON, a British subject and New Zealand citizen of Rural Delivery, Cambridge, New Zealand, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a method and apparatus for milking and more particularly rns . corns a method and apparatus of milking whereby vacuum damage to an animals teats can be minimised.

It is believed that high vacuum in a milk line connected to a teat cup, for example approximately 15 inches of mercury, can lead to vacuum damage and inflamation of the teat if high vacuum is applied to an unstimulated or "slack" teat. In the case of an unstimulated teat, the teat may be slack enough to be drawn down into the teat cup interior, with possible stretching of the teat as the teat cup "crawls" up the teat. In such a case, the weight of the teat cup is supported by the mouth piece of the teat cup gripping the base of the teat. To overcome cup crawl it has been known to weight the teat cup, with consequent pressure on the base of the teat and discomfort to the animal. In addition, existing teat cups require hard mouth pieces to grip the base of the teat under high vacuum. This can also give rise to discomfort.

Apart from possible discomfort to an animal and loss of milk production, the exposure of an unstimulated teat to high vacuum can stretch the teat, particularly the base of the teat, leading to cracking and the presence of a blue or discoloured region. In addition, the high vacuum may give rise to vacuum damage at or inside the teat orifice, such as by back jetting. This damage and possible back jetting of milk into an unstimulated teat increases the likelihood of mastitus.

Others have sought to minimise vacuum damage by reducing the milk line vacuum.

For example, New Zealand patent specification No. 158 416 to Alfa Laval A.B. teaches the use of high and low vacuum lines which can be alternatively coupled to the milk line depending upon milk flow rate. Apart from the expense and extra equipment required this proposal has not proved to be entirely satisfactory as the teat is still subject to the milk line vacuum.

It is an object of this invention to go some way towards overcoming the abovementioned disadvantages in providing an improved method and apparatus for milking.

According to one aspect, this invention provides a method of milking an animal including applying a teat cup to a teat to be milked; the teat cup having an inflation; the interior of the inflation being in communication with a milk line connected to a source of vacuum; the exterior of the inflation being in communication with a pulsating vacuum source; characterised in that before milking commences, the exterior of the inflation is subject to a lower vacuum (i.e.

higher pressure) than the interior of the inflation.

According to another aspect of this invention, there is provided a method of milking an animal including applying a teat cup to a teat to be milked, the teat cup having an inflation, the interior of the inflation being in communication with a milk line connected to a source of vacuum, the exterior of the inflation being in communication with a pulsating vacuum source; characterised in that before milking commences, the exterior of the inflation is subject to a lower vacuum (i.e. higher pressure) than the interior of the inflation to close the inflation about the teat and to prevent milk from entering the milk line.

By subjecting the exterior of the teat cup inflation to a lower vacuum (i.e. higher pressure) than the interior, the teat cup inflation can close snugly about the teat and may effectively close off the milk line vacuum from the teat. At the same time the pulsator can continue to operate to beat or move the inflation about the teat to stimulate the teat so that milk is let down. After a predetermined time, or when the milk has been let down into the teat, the pressure differential between the interior and exterior of the teat can be reduced so that the vacuum applied to the exterior of the teat cup inflation is increased thus allowing the inflation to open and milk to be removed by the milk line vacuum.

According to another aspect of this invention, there is provided milking apparatus for controlling a vacuum level applied exteriorly to an inflation of a teat cup; including a housing, an inlet port, capable of being connected to a source of applied vacuum and an outlet port capable of being connected to the exterior of said teat cup inflation; a valve capable of moving in response to applied vacuum to restrict or close off the inlet port; and means for gradually moving the valve to increase the vacuum level at the outlet port.

By providing means for gradually moving the valve, the vacuum level applied to the exterior of the teat cup inflation can be gradually increased thus changing over from stimulation to milking.

Other aspects of this invention, which should be considered in all its novel aspects, will become apparent from the following description, which is given by way of example only, with reference to the accompanyin drawings in which: Figure 1. illustrates a schematic milking installation.

Figure 2: illustrates a preferred vacuum regulator constructed in accordance with one form of this invention.

Turning now to figure 1, there is illustrated a single teat cup 1 connected to vacuum lincs. It will be appreciated that similar connections may be made to other teat cups and preferably in the case of cows, four teat cups can be provided for each cow, the teat cups being coupled to a vacuum regulator.

As is well known, a teat cup such as 1, has a mouth piece 2 and an inflation 3 which is rcsilicnt and can fit about a teat. The interior of the teat cup inflation is indicated at 4 and is connected via an outlet 3a to a milk line 6. The exterior of the teat cup inflation 3 is indicated at 5 and is in communication with an air line 7.

The milk line 6 is connected to a milk receptacle 8 with a milk outlet 9. A branch vacuum line 10a is connected to a main vacuum line 10.

The air line 7 from the exterior 5 of the teat cup inflation 3 is connected via a pulsator 11 to a branch vacuum line 10h and thus to the main vacuum line 10. The purpose of the pulsator, is to periodically reduce the vacuum in the air line 7 to cause the teat cup inflation 3 to contract about a cows teat to promote milking.

A vacuum regulator 12 is situated in air line 7 between the pulsator 11 and the teat cup 1. Connected to the vacuum regulator 12 is means 13 for gradually increasing the vacuum level applied to the exterior 5 of the teat cup inflation 3.

The operation of such a milking installation will now be described by way of example. The main vacuum line 10 is provided with a constant vacuum of the order of for example only, 15 inches of mercury. The pulsator 11 is set to periodically introduce air to reduce the vacuum in the air line 7 to cause the inflation 3 to squeeze about the teat (not shown) and to then release as the vacuum in the air line 7 increases once again. The milk line vacuum provides an almost constant suction.

When the teat cup 3 is applied to a teat, the vacuum regulator 12 is set so that a vacuum differential appears across the teat cup inflation. That is to say, the pressure on the exterior 5 of the teat cup inflation 3 is maintained higher or the vacuum lower than the pressure or vacuum within the teat cup inflation so that the inflation 3 closes about the teat and closes off or substantially closes off communication between the milk line vacuum and the teat within the inflation 3. By way of example, the regulator 12 can be set initially so that the maximum vacuum applied to the exterior 5 of the teat cup inflation 3 is by way of example, of the order of 3 inches of mercury.It will be appreciated from the foregoing that the main vacuum line is, by way of example, of the order of 15 inches of mercury and that with no milk in the milk line 6, the milk line vacuum will be equivalent to that in the main vacuum line 10. The pressure differential between the interior 4 and the exterior 5 of the teat cup inflation 3 is thus such as to close off the inflation 3 about a teat and prevent or at least substantially reduce the milk line vacuum from causing vacuum damage to the teat.

As the vacuum regulator 12 is positioned between the pulsator 11 and the teat cup 1, the pulsator 11 will continue to operate and thus the teat cup inflation 3 will gently stimulate the teat by squeezing thereagainst.

After a time. the setting of the vacuum regulator 12 can be gradually increased so that the teat cup inflation 3 opens and the vacuum in the milk line 6 can withdraw milk from the teat. It will be appreciated that this operation allows the teat to be stimulated prior to milking and in addition, enables the teat cup 1 to fit snugly about an unstimulated teat when first applied.

As milk rises in milk line 6 to the milk receptacle 8 the head of milk in the milk line 6 will cause the vacuum in the milk line 6 to drop below the level in the main vacuum line 10. With this in mind, it is preferred that the vacuum regulator 12 is set so that the maximum vacuum level applied to the exterior 5 of the teat cup 3 during milking is just below or equal to the vacuum in the milk line 6 at, or adjacent the outlet 3a of the teat cup. It will be appreciated, that this level can be determined by subtracting the head of milk in milk line 6 from the vacuum level in the main vacuum line 10. By this means, the invention enables milking to continue without the teat cup inflation "ballooning" away from the teat.

It will be appreciated that "ballooning" of the inflation can occur when there is a slight positive pressure at the interior 4 of inflation 5, (i.e. a lower vacuum than is applied to the exterior of the inflation). "Ballooning" of the inflation is undesirable as it can give rise to vacuum damage to the teat by stretching the teat, or by allowing the milk line vacuum to enter the mouth piece area of the teat cup.

Moreover, if the air line vacuum level is set at a level equal to or below the vacuum level in the milk line when full of milk (say for example 13 inches of mercury), then when milk flow stops and milk is removed from the milk line 6, the vacuum at the interior 4 of the inflation 3 will increase to say for example 15 inches of mercury. When this occurs the increased pressure differential across the inflation will cause the inflation 3 to close snugly against the teat.

Turning now to figure 2 of the drawings, there is illustrated a preferred form of a vacuum regulator 12. The vacuum regulator is shown as having a housing which includes an upper housing portion 12a and a lower housing portion 12b. The upper and lower housing portions are adapted to be clamped together about, for example, the seal 18 of the diaphragm valve (as will be described by way of example hereinafter). This is by way of example only. In addition, the two housing portions can be formed with a bayonet type connection. Other means of connection can however be used to advantage.

The regulator 12 shown in figure 2 of the accompanying drawings is preferably used to control for example a cluster of four teat cups. Provision can be made to enable two or more units to be coupled together.

Reference to figure 2 of the drawings shows that holes or recesses 31 are provided so that two similar units can be coupled together to provide a double regulator if required. It is envisaged that this will be suitable for a type of milking plant where double pulsators are used, one pulsator being used for each pair of teat cups.

The regulator 12 has an air line passing therethrough, the air line being in the form of an inlet port 14 and an outlet port 15; the inlet port 14 leading into a valve chamber 17 and being connected to the outlet port 15 by an outlet passage 16.

The inlet port 14 leads into and defines a valve seat 48 in the form of a shoulder.

The lower wall 19 of the valve chamber 17 defines a hole or bore 20 passing therethrough.

A valve 21 such as for example a diaphragm valve is mounted within the valve chamber 17 and is secured in position about the wall of the valve chamber, such as by suitable seals. A valve stem 22 is connected to an under side of the diaphragm valve 21 and passes out through the wall 19 of the housing by way of the hole or bore 20.

An actuating lever 23 is attached to a lower end of the valve stem 22 and is pivotally mounted to the housing as shown in figure 2 of the accompanying drawings. The actuating lever 23 is preferably elongate in formation.

A valve spring 24 is located about the valve stem 22 between the actuating lever 23 and the under side of the housing surrounding the hole or bore 20.

A side portion of the housing is formed so as to accommodate and locate means for moving the lever 23; for example a timing mechanism 13 which is provided with a suitable cord 26 which runs from the timing mechanism 13 and is attached to a distal end 23a of the actuating lever 23. The cord 26 then passes through or is attached to, and extends away from, the distal end 23a of the actuating lever 23 and can be provided with a suitable handle or grip 27 is desired.

A lower portion of the housing mounts two spaced apart limit stops 28 and 29. The limit stops 28 and 29 are in the form of elongate members having an elongate body and a head portion with a cam face. The limit stops 28 and 29 are positioned so as to be at least one above and at least one below a butt end 23b of the actuating lever 23 and the limit stops 28 and 29 are pivotally mounted to the housing.

Each limit stop is associated with a plurality of spaced apart protrusions or setting members 30. In use, the body portions of the pivotally mounted limit stops 28 and 29 can be located between two spaced apart protrusions 30 and held in a predetermined or desired position.

In use, the vacuum regulator 12 can be installed in an air line 7 such as in the position shown in figure 1 of the accompanying drawings.

A teat cup is applied to a teat and the cord 26 is pulled downwardly, thus moving the actuating lever 23 in a downward direction as shown in the arrow "A" in figure 2 of the accompanying drawings. This movement is imparted to the valve stem 22 which causes the diaphragm valve 21 to move upwardly in the direction of the arrow "B" shown in figure 2 of the accompanying drawings and thus into juxtaposition with the valve seat 48 at the shoulder of the inlet port. This will then allow only a very small amount of vacuum to pass from the vacuum inlet port 14.

through the vacuum passage 1 6 and to the outlet port 15. A setting such as this maintains a low vacuum at the exterior of the teat cup inflation for a predetermined or desired period of time. The downward movement of the cord 26 will cause the butt end 23h of the actuating lever to move upwardly and this movement will be controlled by the butt end 23b coming into contact with a cam face of the limit stop 28. Thus movement of the limit stop 28 between various protrusions 30, and thus the adjustment of the cam face of the limit stop 2X can serve to "fine tune" the initial inlet of vacuum following the pulling of the cord 26.

The pulling of the cord 26 will cause the cord 26 to come out of the timer 13 and the timing arrangement is such as to then cause the cord 26 to be pulled back into the timer; this will also cause the lever to be gradually moved or pulled upwardly. Any suitable type of timer can be used. but the timer could for example, be a clockwork timer and may if desired, have a visual or audio indicator. In another form of the invention it is envisaged that the timer can be in the form of a music box. and the playing of the music can also have a therapeutic and restful effect on cows.

Following the pulling of the cord 26 and the movement of the diaphragm valve 21 into juxtaposition with the valve seat 48. a small amount of vacuum passes through the passage 16 and into the vacuum outlet 15. If the vacuum in the inlet port increases, the increased differential pressure across the diaphragm 21 will cause it to seal and abut against the valve seat 48; atmospheric pressure being applied to the lower face of the diaphragm whilst the upper is subjected to vacuum.

As the timer operates, the cord 26 is withdrawn into the timer and thus the actuating lever 23 is moved upwardly in the direction of the arrow "C" shown in figure 2 of the drawings. This movement is imparted to the valve stem 22 and the diaphragm valve 21, which is caused to move in a downward direction, as indicated by arrow "D" and thus away from the valve seat 48 and the shoulder. This then increases gradually the amount of vacuum available for passing through the passage 16 into the vacuum outlet 15.

The butt end 23b of the actuating lever 23 is caused to move downwardly in the direction of the arrow "E" and its downward movement can be controlled by the cam face of the second or lower limit stop 29 which can be positioned to "fine tune" the movement, by being positioned between desired or predetermined, and spaced apart protrusions 30. The movement of the lever 23 will be limited and will cease once the butt end 23b comes into contact with the cam face of the lower limit stop 29.

Suitable means of controlling the operation of the timer 13 can be provided, for example suitable clockwork timers and the like can be provided so that the movement of the valve 21 is such that the vacuum will gradually increase to enable the milking to commence, over a predetermined or desired period of time. For example, it has been found that in some cases a period of three minutes provides adequate time for stimulation prior to milking. This can vary however, depending upon various cows.

The setting of the second or lower limit stop 29 can be such as to provide individual adjustment of an air line 7, during milking for a particular cow. For example, teat sizes vary between breeds and cows, and teat cups do not always fit as snugly as is desirable, particularly when a teat is small. By adjusting the lower or second limit stop 29 the vacuum on the exterior of the inflation during milking can be set lower than normal (by causing a lesser opening of the valve) to thus permit the inflation to fit snugly about a small teat. On the other hand, the pressure differential on the inflation can be reduced by setting the stop 29 at a higher vacuum limit (by permitting a greater opening of the valve) where the teat is large.

In addition, the setting of the limit stop 29 can take account of the reduction of the milk line vacuum applied to the interior of the inflation when a head of milk is present in the milk line. Thus, the setting of limit stop 29 can be such that the vacuum level at the exterior of the inflation is always less than or equal to the minimum vacuum present at the interior of the inflation during milking.

It should be appreciated that this invention has been described by way of example only. In particular it should be appreciated that references to examples such as mercury limits and the like are by way of example only and can vary from situation to situation. The claims form part of the disclosure.

It should be appreciated that improvements and modifications can be made to the invention without departing from the scope thereof as defined by the appended claims.

WHAT I CLAIM IS: 1. A method of milking an animal including applying a teat cup to a teat to be milked; the teat cup having an inflation; the interior of the inflation being in communication with a milk line connected to a source of vacuum; the exterior of the inflation being in communication with a pulsating vacuum source; characterised in that before milking commences, the exterior of the inflation is subject to a lower vacuum (i.e.

higher pressure) than the interior of the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. then allow only a very small amount of vacuum to pass from the vacuum inlet port 14. through the vacuum passage 1 6 and to the outlet port 15. A setting such as this maintains a low vacuum at the exterior of the teat cup inflation for a predetermined or desired period of time. The downward movement of the cord 26 will cause the butt end 23h of the actuating lever to move upwardly and this movement will be controlled by the butt end 23b coming into contact with a cam face of the limit stop 28. Thus movement of the limit stop 28 between various protrusions 30, and thus the adjustment of the cam face of the limit stop 2X can serve to "fine tune" the initial inlet of vacuum following the pulling of the cord 26. The pulling of the cord 26 will cause the cord 26 to come out of the timer 13 and the timing arrangement is such as to then cause the cord 26 to be pulled back into the timer; this will also cause the lever to be gradually moved or pulled upwardly. Any suitable type of timer can be used. but the timer could for example, be a clockwork timer and may if desired, have a visual or audio indicator. In another form of the invention it is envisaged that the timer can be in the form of a music box. and the playing of the music can also have a therapeutic and restful effect on cows. Following the pulling of the cord 26 and the movement of the diaphragm valve 21 into juxtaposition with the valve seat 48. a small amount of vacuum passes through the passage 16 and into the vacuum outlet 15. If the vacuum in the inlet port increases, the increased differential pressure across the diaphragm 21 will cause it to seal and abut against the valve seat 48; atmospheric pressure being applied to the lower face of the diaphragm whilst the upper is subjected to vacuum. As the timer operates, the cord 26 is withdrawn into the timer and thus the actuating lever 23 is moved upwardly in the direction of the arrow "C" shown in figure 2 of the drawings. This movement is imparted to the valve stem 22 and the diaphragm valve 21, which is caused to move in a downward direction, as indicated by arrow "D" and thus away from the valve seat 48 and the shoulder. This then increases gradually the amount of vacuum available for passing through the passage 16 into the vacuum outlet 15. The butt end 23b of the actuating lever 23 is caused to move downwardly in the direction of the arrow "E" and its downward movement can be controlled by the cam face of the second or lower limit stop 29 which can be positioned to "fine tune" the movement, by being positioned between desired or predetermined, and spaced apart protrusions 30. The movement of the lever 23 will be limited and will cease once the butt end 23b comes into contact with the cam face of the lower limit stop 29. Suitable means of controlling the operation of the timer 13 can be provided, for example suitable clockwork timers and the like can be provided so that the movement of the valve 21 is such that the vacuum will gradually increase to enable the milking to commence, over a predetermined or desired period of time. For example, it has been found that in some cases a period of three minutes provides adequate time for stimulation prior to milking. This can vary however, depending upon various cows. The setting of the second or lower limit stop 29 can be such as to provide individual adjustment of an air line 7, during milking for a particular cow. For example, teat sizes vary between breeds and cows, and teat cups do not always fit as snugly as is desirable, particularly when a teat is small. By adjusting the lower or second limit stop 29 the vacuum on the exterior of the inflation during milking can be set lower than normal (by causing a lesser opening of the valve) to thus permit the inflation to fit snugly about a small teat. On the other hand, the pressure differential on the inflation can be reduced by setting the stop 29 at a higher vacuum limit (by permitting a greater opening of the valve) where the teat is large. In addition, the setting of the limit stop 29 can take account of the reduction of the milk line vacuum applied to the interior of the inflation when a head of milk is present in the milk line. Thus, the setting of limit stop 29 can be such that the vacuum level at the exterior of the inflation is always less than or equal to the minimum vacuum present at the interior of the inflation during milking. It should be appreciated that this invention has been described by way of example only. In particular it should be appreciated that references to examples such as mercury limits and the like are by way of example only and can vary from situation to situation. The claims form part of the disclosure. It should be appreciated that improvements and modifications can be made to the invention without departing from the scope thereof as defined by the appended claims. WHAT I CLAIM IS:

1. A method of milking an animal including applying a teat cup to a teat to be milked; the teat cup having an inflation; the interior of the inflation being in communication with a milk line connected to a source of vacuum; the exterior of the inflation being in communication with a pulsating vacuum source; characterised in that before milking commences, the exterior of the inflation is subject to a lower vacuum (i.e.

higher pressure) than the interior of the

inflation.

2. A method of milking an animal, including applying a teat cup to a teat to be milked; the teat cup having an inflation; the interior of the inflation being in communication with a milk line connected to a source of vacuum; the exterior of the inflation being in communication with a pulsating vacuum source; characterised in that before milking commences, the exterior of the inflation is subject to a lower vacuum (i.e.

higher pressure) than the interior of the inflation to close the inflation about the teat and to prevent milk from entering the milk line.

3. A method as claimed in claim 1 or claim 2, wherein the level of the vacuum applied to the exterior of the inflation is controlled by a regulator positioned in a vacuum line between a pulsator and the teat cup.

4. A method as claimed in any one of the preceding claims, wherein the level of vacuum applied to the exterior of the inflation before milking commences is less than five inches of mercury.

5. A method as claimed in claim 4 wherein the level of vacuum applied to the exterior of the inflation before milking commences, is about three inches of mercury.

6. A method as claimed in any one of the preceding claims, wherein the vacuum level applied to the exterior of the inflation is increased gradually to a level equal to or below the minimum milk line vacuum present at the interior of the inflation during milking.

7. Milking apparatus for controlling a vacuum level applied exteriorly to an inflation of a teat cup; including a housing; an inlet port capable of being connected to a source of applied vacuum; and an outlet port capable of being connected to the exterior of said teat cup inflation; a valve capable of moving in response to applied vacuum to restrict or close off the inlet port; and means for gradually moving the valve to increase the vacuum level at the outlet port.

8. Apparatus as claimed in claim 7, wherein the means for gradually moving the valve includes a pivotally mounted lever, connected to the valve.

9. Apparatus as claimed in claim 8, wherein the means for moving the lever includes a timing mechanism.

10. Apparatus as claimed in claim 8 or claim 9, wherein the lever is capable of moving between a pair of limit stops to control an initial low level of vacuum and an increased vacuum level.

11. Apparatus as claimed in claim 10 wherein the limit stops are adjustable to preset the two vacuum levels.

12. Apparatus for controlling a vacuum level applied to a teat cup substantially as herein described with reference to either figure 1 or figure 2 of the accompanying drawings.

13. A method of milking an animal substantially as herein described with reference to either figure 1 or to figure 2 of the accompanying drawings.