Milking system and a valve therefor

The invention relates to a milking system. The milking system of the invention includes a plurality of valves each of which is connected to a vacuum line and a milk conveying line at a plurality of spaced locations. Connectors are used which can be readily connected to and disconnected from the valves, each connector serving to supply vacuum from the vacuum line to operate a milking device positioned on a cow's udder and also serving to pass milk from the udder to the milk conveying line. The invention also provides a novel valve for use in the milking system of the invention.

BACKGROUND OF THE INVENTION 
This invention relates to a milking system, and to a valve which may be 
used in such a system. The invention is particularly concerned with a 
milking system in which a cowshed is provided with a source of vacuum 
which is used to effect the milking operation, and milk is conveyed from 
the cowshed by a pipeline. Such a system enables the vacuum required to 
milk all the cows to be supplied from a single vacuum source and enables 
the milk from all the cows to be conveyed directly to a milk tank via the 
pipeline. 
An object of the invention is to provide a milking system which enables a 
vacuum and liquid tight connection to be rapidly and easily made between a 
milking device positioned on the udder on an animal to be milked and 
vacuum and milk conveying lines. 
SUMMARY OF THE INVENTION 
According to the present invention there is provided a milking system for 
milking animals, comprising a vacuum line for connection to a source of 
vacuum, a milk conveying line for connection to a milk receiver, a milking 
device for connection to the udder of an animal to be milked, a plurality 
of valves each connected both to the vacuum line and the milk conveying 
line at a corresponding plurality of spaced locations, each valve 
comprising a body having separate closable milk and vacuum passages 
communicating respectively with the vacuum line and the milk conveying 
line, and a plurality of connector members adapted for ready connection to 
and disconnection from a selected one of the valves, each connector member 
having a first passage providing communication between the milk passage of 
the selected valve and an inlet for milk from the milking device, and 
having a second passage providing communication between the vacuum passage 
and an outlet for vacuum to pass to the milking device. 
The invention also provides a valve having two separate passages 
therethrough, and a valve closure member movable between a position in 
which it blocks both passages and a position in which both passages are 
free, the said closure member being operable from the exterior of the 
valve.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
As shown in FIG. 1, vacuum is supplied to a cowshed by a vacuum line 30, 
and milk is carried away from the cowshed by a milk line 31. These two 
lines run parallel to one another above the cows or other animals to be 
milked, and at intervals along the line valves 1 are secured to both 
lines. Only one of these valves is shown in FIG. 1. The valve 1 is mounted 
on the vacuum line by means of a pair of internally threaded hexagonal 
rods 2 [only one shown], each with a corresponding set screw 3 with two 
hexagonal nuts, plate 4, and U-bolt 5. Each rod two is received in an 
aperture in the valve and the screw 3 passes through the plate 4 and into 
the rod 2. The plate 4 is held in position on the vacuum line by the 
U-bolt 5. 
The milk line and the vacuum line each have an aperture 6 in their walls, 
and passages 7 and 8 [see FIG. 2] in the valve 1 are aligned and in 
communication with these apertures. The junctions between the apertures 6 
and the passages 7 and 8 are sealed by means of seals 9 which are clamped 
to the milk and vacuum lines by adjustable clips 10. 
The valve is provided with a pair of longitudinally grooved side rails 11 
behind which is received a slidable plate 12. The side rails are provided 
with two pairs of opposing part-circular cut-outs 13 and 14. The cut-outs 
13 are spaced vertically from the passage 7 by an amount which is equal to 
the spacing of the cut-outs 14 above the passage. The plate 12 is provided 
with a lower lip which limits the upward movement of the plate, and has 
two cut-outs 15 and 16. When the plate is in its highest position the 
cut-outs 13 and 15 are aligned and the cut-outs 14 and 16 are aligned. The 
reason for this is explained below. 
Seals 17 surround the outlets passages 7 and 8. Part of one of these seals 
is shown in more detail in FIG. 3. The characteristics of this seal are 
discussed below. 
As is shown both in FIG. 1 and in FIG. 4, the system includes a plug-handle 
18. The handle comprises a forward member 19, a handle portion 20, and a 
connecting member 21. The forward member carries two annular bosses 22 and 
23. The bosses are of such a diameter and are so spaced apart that when 
the plug-handle is moved towards the valve the boss 22 passes through the 
cut-outs 13 and 15, and the boss 23 passes through the cut-outs 14 and 16. 
A right-angled channel 24 extends from the interior of the boss 22 through 
the connecting member 21 and through the handle portion 20. Access to this 
channel can be obtained if desired by removing a plug 25 located at the 
right-angle of the channel. A short channel 26 extends rearwardly from the 
interior of the boss 23. A pulsator 27 [shown in part] is connected to the 
channel 26, and the pulsator is itself connected to a milking device, 
known as a cluster, for placing on an udder of a cow. The channel 20 is 
also connected to the milking device for the purpose of receiving milk 
therefrom. 
A hook 28 is secured to the vacuum line to provide somewhere on which the 
cluster can be hung when not in use. 
The operation of the milking system is as follows. The cluster is attached 
to a cow. [In practice there will be a number of clusters and a 
corresponding number of plug-handles and valves, but for simplicity the 
operation will be described with respect to one cluster]. The plug-handle 
is then moved into contact with the valve 11 so that the bosses 22 and 23 
pass through the cut-outs 13, 15 and 14, 16 respectively. The plug-handle 
is then moved downwardly, causing the plate 12 to move downwardly also, 
until the bosses 22 and 23 are in alignment with the passages 7 and 8 
respectively. The form of the seal 17 [FIGS. 3a and 3b] enables the 
sliding movement of the plate 12 to take place easily. It will be observed 
that the seal 17 comprises a first radially innermost, annular portion 
17a, and second, intermediate, annular portion 17b, and a third radially 
outermost, annular portion 17c. The portion 17c has a bevelled surface 
17d, and the portion 17b is undercut. The portion 17a extends further 
axially from the plate 12 than the rest of the seal. When the leading edge 
of the plate 12 engages the seal 17, the initial engagement is with the 
bevelled surface 17d which prevents pick-up of the seal. As the leading 
edge of the plate 12 continues to move across the seal the portion 17c 
flexes axially away from the plate. This flexing action is assisted by the 
fact that the section 17b is thinner than the section 17c. FIG. 3a shows 
the seal before engagement by the plate 12 and FIG. 3b shows the seal 
after engagement. 
Vacuum in the vacuum line is thus communicated to the pulsator which 
applies a pulsating vacuum to the cluster, and the milk from the cow 
passes through the plug-handle and valve into the milk line under the 
action vacuum applied to the milk line. When the milking operation has 
finished, the plug-handle is moved upwardly and disengaged from the valve. 
The plate 12 then seals the passages 7 and 8.