GB1572939A

GB1572939A - Valve for milking machines

Info

Publication number: GB1572939A
Application number: GB2851277A
Authority: GB
Original assignee: Entecon Ltd
Current assignee: Entecon Ltd
Priority date: 1977-07-07
Filing date: 1977-07-07
Publication date: 1980-08-06

Description

(54) IMPROVEMENTS RELATING TO A VALVE FOR MILKING MACHINES (71) We, ENTECON LIMITED, a Body Corporate organised under the Laws of Great Britain, of Blackwater Bridge, London Road, Blackwater, Camberley, Surrey GU17 9AP, England, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be described in and by the following statement:- This invention relates to a valve for automatic milking machines as used in the dairy herd industry.

It is known to provide milking machinery which includes a cluster of suction heads to be applied to the cow's udder, ram means for moving the cluster towards and away from the udder, a so-called jar to receive milk drawn by suction from the cluster, and means for transfer of milk from the jar to another container such as a refrigerated bulk milk tank.

During the operation of milking, there is initially a relatively high flow rate of milk from the cluster to the jar, but as the udder becomes dry the flow rate reduces and eventually terminates. It is already known to provide automatically operating valve means which sense the termination of the milk flow from the cluster and thereupon cause actuation of the ram means to withdraw the cluster from the udder. There may be temporary stoppages, or reductions, in the milk flow even before the udder has become empty. It is accordingly very desirable to ensure that the ram, serving to withdraw the cluster from the udder, does not operate too soon, as a result of an inadvertent stoppage or slackening of flow, nor that the ram should operate instantaneously upon termination of flow due to the udder becoming dry.

According to the present invention a valve for a milking machine comprises a chamber having an upper inlet for connection to a jar, an outlet valve constituted by an outlet opening and a movable elongated valve element adapted to move in said opening with a gap between the element and the opening, and a float in the chamber carrying the valve element, said gap remaining constant over a predetermined distance of movement of the float, said float and valve element being movable to a raised position in which the opening is unobstructed by the valve element for full flow. A bypass may be provided between a point intermediate the inlet and outlet, to a point downstream of the outlet.

With such a construction, when there is full milk flow from the udder, the milk passing into the chamber causes the float to rise and withdraw the valve element from the opening. The milk in the chamber then flows free through the outlet and, if the incoming flow is greater than can be handled by the outlet, the excess may pass through the bypass conduit. When flow from the udder begins to reduce,- or temporarily ceases, the level of milk in the chamber falls and eventually the valve element passes down into a position in which it defines with the opening the minimum flow gap. Accordingly, there is maintained a continued, but reduced, flow until such time as the chamber has completely emptied. A time delay may be provided between ceasing of milk flow from the cluster and . the operation of the conventional withdrawing means.If there is a temporary inadvertent stoppage of flow, during full milking, the withdrawing means is not unwantedly caused to operate too soon.

The float may be adapted to actuate a switch means for control of the remainder of the milking circuit, and in a convenient form the float carries an upward extension which serves for tripping of a switch mounted above the monitoring chamber.

The delay between cessation of full milk flow may be varied by alteration of the height of the upward extension.

The valve element may advantageously be tapered at its lower end to ensure correct location at each time of lowering into relationship with the valve seating.

In a preferred embodiment, the entire valve is made of stainless steel, and the valve element is a 7 mm diameter rod which, when within the 7.22 mm diameter valve seating, defines therewith a clearance which gives a critical flow rate of 0.22 kgs./min.

In order that the nature of the invention may be readily ascertained, an embodiment of a valve in accordance therewith, and its manner of operation in a milking circuit, are hereinafter particularly described with reference to the figures of the accompanying drawings, wherein: Fig. 1 is a schematic diagram of a milking circuit, including the valve, in a "milking" condition, and Fig. 2 is a corresponding diagram of the circuit when in a "transfer" or "rest" condition.

The circuit comprises a conduit 1 which permits inflow of milk from a cluster (not shown). The conduit 1 communicates with an inlet 2 at the upper part of a chamber 3 having at its base an outlet tube 4. The chamber 3 is composed of a lower body portion 3a onto which is screw-threaded an upper cap portion 3b. At the base of the chamber 3 there is defined an outlet valve seating 5. Within the chamber 3 there is disposed with clearance, a float 7 carrying at its lower end a valve element 8. A bypass conduit 6 provides communication between the upper part of the chamber 3 above the lowered float with the outlet tube 4. The element 8 is a cylindrical rod having a conically tapered lower end 8a. The internal diameter of the seating 5 is 7.22 mm. and the external diameter of the cylindrical rod 8 is 7 mm.At its upper part, the float 7 carries an upward extension 9 on which is adjustably mounted a tripping member 10.

The outlet tube 4 is connected by a conduit 11 to a jar 12, and the jar 12 has an outlet conduit 13 leading through a pulse relay 14 to a line 15 under constant suction.

Above the chamber 3 there is disposed an air trip valve 16 which has an opening to atmosphere normally closed by a valve element 17 connected to a two-arm pivoted trip lever 18. The valve 16 is connected by a conduit 19 to a diaphragm chamber 20 of a pulse relay 21 in which a valve element 22 is adapted to open or to close a valve opening 23 according to whether or not the chamber 20 is respectively under suction or atmospheric pressure. The conduit 19 is connected to a line 24 opening into the valve 20 and also connected by a line 25 to the diaphragm chamber 14a of relay 14, and by a line 26 to the diaphragm chamber 27 a reversing relay 28. The valve opening 23 is connected to a pulsed suction line 29 which is also connected through a branch 30 to the relay 28.According to the position of the valve element 28a, the pulsed suction branch 30 is placed into or out of communication with the cylinder 31 of a hydraulic ram used for moving the cluster away from the udder.

In the condition shown in Fig. 1, all of the system with the exception of the interior of the valve 28 and the ram 31 is under suction.

Accordingly, the valve element 28a remains in the position shown and the ram is not operable. Suction is applied to the cluster through items 15, 14, 13, 12, 11, 6, 2 and 1, and accordingly milk is drawn off at a rapid rate and passes into the chamber 3. Whilst there is a full flow of milk, the float 7 maintains the valve element 8 clear of the seating 5, and milk flows freely to the jar 12, and any excess flow goes through the bypass 6. When flow begins to reduce, the float starts to lower, and the valve rod 8 eventually passes into the opening in the seating 5 to define a gap between the rod 8 and the tube 4 having a minimum clearance.

Thus, even if the milk flow from the cluster now terminates completely, there will still be a delay period during which the float slowly passes downwardly at a rate determined by milk flow through the small clearance and during which this clearance remains of constant area. When the float reaches a predetermined lowered position, the tripping member 10 actuates the lever 18 to open the valve element 17, thereby permitting atmospheric pressure to reach the valve 20 with the result that valve 22, 23 closes. This is the condition shown in Fig. 2. Closure of valve 22, 23 ensures that there is no loss of suction of line 29 to atmosphere. At the same time, opening of line 25 to atmosphere permits valve 14 to close and the suction is removed from the jar 12.Further, opening of line 26 to atmosphere permits relay 28 to open with the result that pulsed suction from line 29, through branch 30, reaches the ram 31 and causes action of the ram to withdraw the cluster from the udder.

It will be seen that the time interval between lowering of the milk supply, from the cluster, to the minimum flow rate ensured by the valve rod 8 and seating 5, and changing of the circuit operation from that of Fig. 1 to that of Fig. 2 is determined by the constants of the valve, and the height setting of the tripping member 10.

To initiate milking, the valve element 22 is shifted manually from the position of Fig.

2 to that of Fig. 1.

In a practical embodiment, the valve is a closed stainless steel cylinder 7.6 cm diameter and 28.5 cm tall with an inlet at the top and two outlet tubes, one at the centre of the base and the other at the side. Inside the cylinder is a stainless steel float, of 6.0 cm diameter and 13.6 cm long, with a shaft of 3.2 mm diameter at the top centre extending through the top of the cylinder to carry the tripping member. On the bottom of the float is a 7 mm diameter shaft 50 mm long and tapered at the end, which fits into an outlet hole of 7.22 mm diameter at the bottom of the cylinder. The valve only becomes effective at flow rates below 0.22 Kgs./min. Above this rate, the shaft below the float rides out of the metering hole. The "take off" time for the cluster depends on (a) the relative rates of milk entering and leaving the cylinder, and (b) the effective volume of the cylinder.The rate at which the milk flows through the metering hole is fixed at 0.22 Kgs./min., but the rate at which milk enters the cylinder is unpredictable.

The effective volume of the cylinder can be varied by adjusting the distance the float must fall before the tripping member 10 operates the valve 17. The following figures show a range of delay times and effective volumes when the tripping member 10 is moved in 10 mm steps up the shaft 9 and when milk flow abruptly stops at 0.22 kgs/min. In practice there is an average delay time of 1.2 minutes from the time when the cylinder becomes effective to the removal of the cluster with the tripping element 10 set at 20 mm.

Volume of milk Position of tripping member Delay period from passing through 10 on shaft 9 end of milk flow restrictor 10 mm 0.38 mins. 65 ml 20 mm 0.59 mins. 102 ml 30 mm 0.83 mins. 145 ml 40 mm 1.08 mins. 188 ml 50 mm 1.28 mins. 224 ml WHAT WE CLAIM IS: 1. A valve for a milking machine comprising a chamber having an upper inlet for connection to a jar, an outlet valve constituted by an outlet opening and a movable elongated valve element adapted to move in said opening with a gap between the element and the opening, and a float in the chamber carrying the valve element, said gap remaining constant over a predetermined distance of movement of the float, said float and valve element being movable to a raised position in which the opening is unobstructed by the valve element for full flow.

2. A valve as claimed in claim 1 wherein the opening is provided by a tube into which the valve element enters.

3. A valve as claimed in claims I or 2 wherein the valve element is tapered at its lower end to ensure correct location at each time of lowering into relationship with the valve seating.

4. A valve as claimed in claims 1, 2 or 3 made of stainless steel.

5. A valve as claimed in any preceding claim, wherein the valve element is a rod of 7 mm external diameter and the valve opening has an internal diameter of 7.22 mm.

6. A valve as claimed in any of the preceding claims in combination with means carried by the float for operation in valve means controlling a cluster operating ram.

7. A valve as claimed in any of the preceding claims having a by-pass conduit connecting the upper part of the chamber above the lowered float to the outlet.

8. A valve substantially as described herein with reference to the figures of the accompanying drawings.

9. A milking machine comprising a jar, a ram for operating a cluster, a ram control valve, a first suction duct connected to said ram control valve, a suction duct closing valve, a second suction duct connected to the jar, a jar control valve between the second suction duct and the jar, an air trip valve to open the ram control valve, suction duct closing valve and jar control valve to atmosphere, a milk flow valve as claimed in any of claims 1 to 6, and means whereby the float in a predetermined lowered position operates the air trip valve.

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

Claims

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

cm diameter and 13.6 cm long, with a shaft of 3.2 mm diameter at the top centre extending through the top of the cylinder to carry the tripping member. On the bottom of the float is a 7 mm diameter shaft 50 mm long and tapered at the end, which fits into an outlet hole of 7.22 mm diameter at the bottom of the cylinder. The valve only becomes effective at flow rates below 0.22 Kgs./min. Above this rate, the shaft below the float rides out of the metering hole. The "take off" time for the cluster depends on (a) the relative rates of milk entering and leaving the cylinder, and (b) the effective volume of the cylinder. The rate at which the milk flows through the metering hole is fixed at 0.22 Kgs./min., but the rate at which milk enters the cylinder is unpredictable.

The effective volume of the cylinder can be varied by adjusting the distance the float must fall before the tripping member 10 operates the valve 17. The following figures show a range of delay times and effective volumes when the tripping member 10 is moved in 10 mm steps up the shaft 9 and when milk flow abruptly stops at 0.22 kgs/min. In practice there is an average delay time of 1.2 minutes from the time when the cylinder becomes effective to the removal of the cluster with the tripping element 10 set at 20 mm.

Volume of milk Position of tripping member Delay period from passing through

10 on shaft 9 end of milk flow restrictor

10 mm 0.38 mins. 65 ml

20 mm 0.59 mins. 102 ml

30 mm 0.83 mins. 145 ml

40 mm 1.08 mins. 188 ml

50 mm 1.28 mins. 224 ml WHAT WE CLAIM IS: 1. A valve for a milking machine comprising a chamber having an upper inlet for connection to a jar, an outlet valve constituted by an outlet opening and a movable elongated valve element adapted to move in said opening with a gap between the element and the opening, and a float in the chamber carrying the valve element, said gap remaining constant over a predetermined distance of movement of the float, said float and valve element being movable to a raised position in which the opening is unobstructed by the valve element for full flow.
2. A valve as claimed in claim 1 wherein the opening is provided by a tube into which the valve element enters.
3. A valve as claimed in claims I or 2 wherein the valve element is tapered at its lower end to ensure correct location at each time of lowering into relationship with the valve seating.
4. A valve as claimed in claims 1, 2 or 3 made of stainless steel.
5. A valve as claimed in any preceding claim, wherein the valve element is a rod of 7 mm external diameter and the valve opening has an internal diameter of 7.22 mm.
6. A valve as claimed in any of the preceding claims in combination with means carried by the float for operation in valve means controlling a cluster operating ram.
7. A valve as claimed in any of the preceding claims having a by-pass conduit connecting the upper part of the chamber above the lowered float to the outlet.
8. A valve substantially as described herein with reference to the figures of the accompanying drawings.
9. A milking machine comprising a jar, a ram for operating a cluster, a ram control valve, a first suction duct connected to said ram control valve, a suction duct closing valve, a second suction duct connected to the jar, a jar control valve between the second suction duct and the jar, an air trip valve to open the ram control valve, suction duct closing valve and jar control valve to atmosphere, a milk flow valve as claimed in any of claims 1 to 6, and means whereby the float in a predetermined lowered position operates the air trip valve.