Distributor device for a milking cluster

Abstract

A distributor device 111 for distributing fluid to teat cups of a milking cluster, with an inlet manifold, an outlet manifold, a drain passageway 48 leading to a drain outlet 49, and first valve 30 an

Description

FIELD OF THE INVENTION The present invention relates to distributor device for distributing fluid to teat cups of a milking cluster. BACKGROUND OF THE INVENTION Conventionally, milking equipment installed in a milking parlour comprises a milking point at each animal stall within the parlour. Each milking point includes a milking cluster of teat cups for connecting the milking equipment to the teats of an animal to be milked. In the case of cows, for example, each milking cluster has four teat cups. The cluster additionally comprises a claw or clawpiece which connects short pulse tubes and short milk tubes leading from the teat cups, respectively, to a long pulse tube coupled to a pulsator and a long milk tube connected to a milk collection system. Each teat cup comprises a rigid hollow shell supporting a resilient or flexible liner which has a barrel portion for engaging about a teat and which has, at its upper end, an head portion with a mouth through which the teat is engaged with the barrel of the liner. At the opposite discharge end of the teat cup, the liner communicates with a short milk tube which delivers milk extracted from an animal's teat to the claw where it is collected and delivered to the long milk tube. A short pulsator tube is connected, at one end, to the annular space or pulse chamber between the shell and the liner and, at its opposite end, is connected, via a device on the claw, to the long pulsation tube and a pulsator. Upon commencement of milking, vacuum is applied to the teat cups of a milking cluster at each milking point via the long milk tube, the claw and the short milk tubes for the purposes of extracting milk from the teat cups. This vacuum also leaks between the barrel of each liner and the engaged teat and is applied to a void formed about the teat in the head of a liner in order to capture the cup on the teat. Milking is performed by automatically and alternately applying vacuum and atmospheric pressure pulses produced by the pulsator to the pulse chamber of each teat cup in order to flex the liner and stimulate discharge of milk from the engaged teat. It is customary to apply these pneumatic pulses alternately to pairs of teat cups of a cluster. After completion of the milking cycle, the teats are disinfected and the teat cup liners are flushed internally with treatment fluids such as disinfectant and water and are dried with compressed air. To this end, teat cups may be fitted with injection nozzles for injecting treatment fluids into the heads of the liners as described in WO 2005 / 043986. The treatment fluid is fed to the injection nozzles via a distributor on the clawpiece of the milking cluster. Alternatively, or in addition, treatment fluids may be supplied to each teat cup via a back flush valve disposed at the discharge end of the teat cup. In either event, upon take-off of the milking cluster from the animal, the milking cluster is designed to enable the short milk tubes to fall away from the centre line of the cluster so that the teat cups are inverted and hang with their heads downwardly from the claw in a rest position. Injection of treatment fluid via the distributor may be performed with the teat cups in this rest position. Consequently, liquid can escape through the head portions of the teat cups. Where treatment fluids are injected into the liners of the teat cups, post milking, for example as described in the aforementioned WO 2005 / 043986, the treatment fluid is delivered to the different teat cups of a milking cluster via a distributor on the clawpiece which includes a safety valve to prevent treatment fluid entering the liners and contaminating the milk in the event of a control system malfunction. As described in WO 2014 / 016596 A1, a distributor device may incorporate a safety valve which, in a rest position, shuts off the fluid flow of treatment fluid through the distributor and vents to atmosphere during the milking cycle. It is an object of the present invention to provide an improved distributor device with additional safety features to further guard against malfunctions. SUMMARY OF THE INVENTION According to a first aspect of the invention, there is provided a distributor device for distributing fluid to teat cups of a milking cluster. The distributor device comprises an inlet manifold, an outlet manifold, a drain outlet, a drain passageway leading to the drain outlet, a fluid path configured to pass fluids from the inlet manifold to the outlet manifold, and first and second valves arranged in series along the fluid path. The first valve comprises a first movable valve body and the second valve comprises a second movable valve body, wherein the fluid path comprises an intermediate portion between the first and second valves. The first and second valves have a closed configuration in which the first movable valve body is positioned to block fluid flow from the inlet manifold to the intermediate portion and the second movable valve body is positioned to block fluid flow from the intermediate portion to the outlet manifold and to allow fluid flow from the intermediate portion to the drain passageway. The first and second valves have an open configuration in which the first movable valve body is positioned to allow fluid flow from the inlet manifold to the intermediate portion and the second movable valve body is positioned to allow fluid flow from the intermediate portion to the outlet manifold and to block fluid flow from the intermediate portion to the drain passageway. The valves may be moved to the closed configuration during the milking cycle, and moved to the open configuration when treatment fluids are to be delivered to the teat cups. The provision of a distributor device having both first and second valves in series with a drain outlet between them enhances the safety of the distributor device and makes it even more unlikely that fluids delivered to the teats cups via the distributor device would ever enter the teat cups during the milking cycle. If there was a failure upstream of the distributor device causing fluid to be sent to the distributor device during the milking cycle then the fluid would be blocked by the first valve. Even if the first valve was to fail, the fluid passing through the first valve would be routed to the drain outlet by the second valve. The drain outlet may open to atmosphere such that any fluid exiting the drain valve will fall from the drain outlet to the floor and provide a visual indication of the failure of the first valve, so the distributor device can be fixed or replaced and the equipment upstream of the distributor device can be checked. Optionally, the distributor device may have a further drain passageway leading into the drain outlet or into a further drain outlet. In the closed configuration, the first movable valve body may be positioned to block fluid flow from the inlet manifold to the intermediate portion and also to allow fluid flow from the inlet manifold to the further drain passageway. Then if there was a failure upstream of the distributor device causing fluid to be sent to the distributor device during the milking cycle, the fluid would flow into the further drain passageway and out of the drain outlet or the further drain outlet, providing a visual indication of the failure to the user. Each of the valves may comprise a valve bore along which the corresponding movable valve body may be slidable to transition the valves between the open and closed configurations. The fluid path may include the valve bores and the valves may have valve ports leading out of the valve bores. The movable valve bodies may be configured to block or open the valve ports to block or allow passage of fluids out of the valve bores via the valve ports. The valve ports may each comprise an O-ring seal and a valve seat, the O-ring seal being compressed between the movable valve member and the valve seat when the valve port is closed to block flow of fluid. Each O-ring seal may be fixedly mounted around the corresponding movable valve member, or fixedly mounted around the corresponding valve seat. The second valve may comprise first and second valve ports leading out of the valve bore, the first valve port leading into the outlet manifold and the second valve port leading to the drain passageway. The second movable valve body may be slid in one direction to block the first valve port and open the second valve port in the closed configuration, and slid in an opposite direction to open the first valve port and close the second valve port in the closed configuration. The first valve port may be a distal valve port and the second valve port may be a proximal valve port, the distal valve port may be nearer a distal end of the second movable valve body than the proximal valve port. The fluid path through the first valve may extend from the inlet manifold to the intermediate portion via the valve bore and the valve port of the first valve, and the fluid path through the second valve may extend from the intermediate portion to the outlet manifold via the valve bore and the first valve port of the second valve. The first and second valves may comprise one or more springs that urge the first and second movable valve bodies into the closed configuration of the valves, so that the valves block flow of fluid from the inlet to the outlet manifolds by default for safety. The movement of both the first and second movable valve bodies may be controlled by a single control input that either moves both valves into the closed configuration or moves both valves into the open configuration. Accordingly, the first and second valves may not be controllable independently of one another to save any need for additional control inputs and to simplify the control of the distributor. The valves are preferably controlled pneumatically, and a single pneumatic control inlet may be provided for receiving compressed air to move both the first and second movable valve bodies into the open configuration. The first and second movable valve bodies may move back into the closed configuration, for example under a spring bias, when the compressed air is no longer sent to the pneumatic control inlet. Pneumatic control is typically less susceptible to failure than electric control, since electric wires may be susceptible to breakage under repeated bending as the milking cluster is moved from place to place. The first and second movable valve bodies may comprise one or more piston surfaces configured to be driven pneumatically to control movement of the first and second movable valve bodies. This provides a simple and effective manner of controlling the states of the valves. The distributor device may distribute more than one type of fluid to the teat cups of the milking cluster, for example teat dip for treating the teats of the animal after miking and disinfecting / rinsing fluids for cleaning the teat cups after take-off from the teats. Accordingly, the inlet manifold may comprise two inlets connected to two respective inlet passageways, one inlet for teat dip and the other inlet for disinfecting / rinsing fluids. The inlet for teat dip may be fitted with a non-return valve, so that the teat dip can be maintained primed up to the distributor. The two inlet passageways may lead from the inlets towards the valve bore of the first valve. There is a desire to make the distributor device light and compact so that it is suitable for mounting on the clawpiece of a milking cluster, but also economic to manufacture. Accordingly, the inlet manifold may comprise a first valve passageway that is transverse to the valve bore of the first valve and intersects with the valve bore of the first valve, wherein the two inlet passageways are both connected to the first valve passageway. The two inlet passageways may be transverse to the first valve passageway and each intersect with the first valve passageway. Therefore, the two inlet passageways may run in parallel with the valve bore of the first valve, alongside the valve bore of the first valve. The two inlet passageways may be connected to the first valve passageway at opposing sides of the first valve to one another, and the valve bore of the first valve may be between the two inlet passageways, providing a compact construction. Each inlet passageway preferably begins at an inlet nipple emanating from the exterior of the distributor device and to which a fluid line for delivering fluids can be connected. The outlet manifold preferably also has similar outlet nipple(s) for connecting fluid lines that lead to the teat cups. The intermediate portion leads fluids from the first valve to the second valve. To provide a compact construction, the first valve may be positioned alongside the second valve, for example one above the other. The first and second valves may be positioned with one directly above the other, alongside one another in parallel, and the two inlet nipples may be positioned on opposing sides of the valves from one another. It is desirable for the inlet nipples to be remote from the outlet nipples to assist in the connection and routing of fluid lines to and from the distributor, and so with the first and second valves arranged alongside one another, the intermediate portion may comprise one or more linking passageways that lead fluid passing from the first valve to the second valve in a direction back towards the inlet nipples. The valve port of the first valve may lead into an upstream passageway of the intermediate portion, and a downstream passageway of the intermediate portion may lead into the valve bore of the second valve, with the one or more linking passageways extending from the upstream passageway to the downstream passageway. The one or more linking passageways may extend transverse to the upstream and downstream passageways to provide a compact intermediate portion. In one example, there may be two of the linking passageways, each linking passageway extending from the upstream passageway to the downstream passageway, wherein the two linking passageways are at opposing sides of the first valve from one another and at opposing sides of the second valve from one another. Thus fluid can travel through the distributor through both of the linking passageways, easing the flow of fluid through the distributor. The upstream passageway may be transverse to the valve bore of the first valve and intersect with the valve bore of the first valve, and the downstream passageway may be transverse to the valve bore of the second valve and intersect with the valve bore of the second valve, to provide a compact interface between the valves and the intermediate portion. The upstream passageway may intersect with the valve bore of the first valve at a location along the upstream passageway that is in between the intersections of the two linking passageways with the upstream passageway. This allows fluid to leave the valve bore on both sides of the valve bore, via the valve port, easing the flow of fluid out of the first valve. Similarly, the downstream passageway may intersect with the valve bore of the second valve at a location along the downstream passageway that is in between the intersections of the two linking passageways with the downstream passageway. This allows fluid to enter the valve bore on both sides of the valve bore, easing the flow of fluid into the second valve. The downstream passageway preferably intersects with the valve bore of the second valve at a location along the valve bore that is in between the first and second valve ports of the second valve, allowing the fluid flowing into the valve bore of the second valve to flow along the valve bore to either the first valve port or the second valve port depending on the position of the second movable valve member. The outlet manifold may comprise a second valve passageway that is transverse to the valve bore of the second valve and intersects with the valve bore of the second valve, and wherein the first valve port of the second valve leads into the second valve passageway. The transverse direction of second valve passageway provides space for plural outlet passageways leading from the second valve passageway. The outlet manifold may comprise two outlet passageways intersecting with the second valve passageway, and the intersection of the second valve passageway with the valve bore of the second valve may be in between the intersections of the second valve passageway with the two outlet passageways, helping to keep the distributor device compact. Each outlet passageway may lead into at least one nipple for connecting pipes leading to milking teat cups. For example, there may be two outlet nipples leading from each of two outlet passageways, providing four outlet nipples in total for connection to four corresponding teat cups. The two outlet passageways may be transverse to and intersect with the second valve passageway, and the outlet nipples may extend transversely from the two outlet passageways, emanating at the sides of the distributor device. The inlet nipples may be at one end of the distributor device, so the inlet and outlet nipples are in different regions to one another at the exterior of the distributor device. The distributor device may comprise a first unitary block of material that defines the inlet manifold, the outlet manifold and the intermediate portion. The various passageways may for example be formed by moulding or drilling into the unitary block of material to provide economic manufacturing. Advantageously, the ends of the moulded or drilled passageways may be terminated by forcing ball bearings into their ends. The first unitary block of material may also define part of the valve bores of the first and second valves. The first unitary block of material may for example be a block of plastics material. The distributor device may comprises a second unitary block of material that is fitted into the first block of unitary material, wherein the second unitary block of material at least partially houses the first and second movable valve bodies. The first and second movable valve bodies may be captured between the first and second unitary blocks of material when they are fitted together, allowing for economic assembly of the distributor device. The second unitary block of material may for example be a block of plastics material. The first and second unitary bodies of material may be screwed or bolted to one another, allowing them to be disassembled if required, for example to replace the first or second movable valve bodies. The first valve may be positioned above the second valve, and the drain passageway may extend from the second valve port of the second valve to an opening on the lower surface of the distributor device, the opening being the drain outlet. Accordingly, any residual fluids remaining in the intermediate portion once the valves have been moved into the closed configuration can drain out of the drain outlet under gravity. It is desirable to provide a manner of flushing the drain outlet, to prevent any dirt from accumulating in the drain outlet and causing a blockage. Therefore, upon transitioning from the closed configuration to the open configuration, the first movable valve body may be configured to allow fluid flow from the inlet manifold to the intermediate portion before the second movable valve body has moved so far as to block fluid flow from the intermediate portion to the drain passageway. Thus, there is a portion of the travel of the second movable valve body which allows fluid sent to the distributor to flow through the first valve and out of the drain outlet under pressure. When the valves are controlled pneumatically, the moveable valve bodies move quickly and there is only a short interval of time between the valve port of the first valve opening and the second valve port of the second valve closing, and so a short time period in which the drain outlet can be flushed. According to a second aspect of the invention, there is provided milking equipment comprising the distributor device of the first aspect and control equipment. The control unit may be configured to control the positions of the first and second movable valve bodies, for example by sending compressed air to the pneumatic control inlet when the valves are to be opened. The control equipment may also be configured to control the fluids that are sent to the inlet manifold, for example disinfectant or flushing fluid such as water. The control equipment may be configured to send fluids to the inlet manifold whilst repetitively cycling the valves between the open and closed configurations, for example at a cycle rate of at least 1 Hz. The short time period in which the drain outlet is flushed by the fluids being sent to the distributor is repeated every cycle, and so once multiple cycles have been completed the drain outlet has been sufficiently flushed and cleaned of any dirt. The cycle rate may be greater than 5 Hz so that faster flushing of the drain outlet can take place. According to a third aspect of the invention, there is provided a milking cluster comprising a clawpiece and teat cups connected to the clawpiece, wherein the distributor device of the first aspect is mounted on the clawpiece, and wherein fluid lines are connected from the outlet manifold of the distributer device to the teat cups for delivering fluids to the teat cups. The mounting of the distributer device on the clawpiece keeps the distributer device from moving about or becoming damaged. DETAILED DESCRIPTION Embodiments of the invention will now be described by way of non-limiting example only and with reference to the accompanying drawings, in which: Fig. 1a shows a schematic diagram of milking equipment according to an embodiment of the present invention; Fig. 1b shows a schematic exploded diagram of part of the milking equipment of Fig. 1a including distributor device; Fig. 2 shows a schematic perspective diagram of the distributor device of Fig. 1b; Fig. 3 shows a schematic plan diagram of the distributor device of Fig. 1b; Fig. 4 shows a schematic side elevation of the distributor device of Fig. 1b; Fig. 5 shows a cross-sectional diagram taken along XSH1 marked on Fig. 4 with the distributor device in a closed configuration; Fig. 6 shows a cross-sectional diagram taken along XSH2 marked on Fig. 4 with the distributor device in the closed configuration; Fig. 7 shows a cross-sectional diagram taken along XSV1 marked on Fig. 3 with the distributor device in the closed configuration; Fig. 8 shows a cross-sectional diagram taken along XSV2 marked on Fig. 3; Fig. 9 shows a cross-sectional diagram taken along XSH1 marked on Fig. 4 with the distributor device in an open configuration; Fig. 10 shows a cross-sectional diagram taken along XSH2 marked on Fig. 4 with the distributor device in the open configuration; and Fig. 11 shows a cross-sectional diagram taken along XSV1 marked on Fig. 3 with the distributor device in the open configuration. The figures are not to scale, and same or similar reference signs denote same or similar features. The drawings are not to scale. Same or similar reference signs denote same or similar features. The schematic diagram of Fig. 1a shows milking equipment 100 installed in a milking parlour for cows. The part of the parlour shown in Fig. 1a comprises five animal stalls for cows, in each of which there is a milking point 101 including a milking cluster 102 of four teat cups and stall control equipment 103. Each stall control equipment may comprise a pulsator 103a, a control valve 103b, and a control mechanism 103c. Each pulsator 103a may receive a vacuum from a common vacuum source 116, and output differential pressure pulses to a respective control valve 103b. Each control valve 103b may be connected to a common electrical control unit 109 via a cable 110. During milking, the electrical control unit 109 may control the control valve 103b to output the differential pressure pulses along pulse lines 114 and 115, towards the corresponding milking cluster 102. Each control mechanism 103c may have solenoid valves which selectively control the delivery of various fluids such as high pressure compressed air, teat dip and flushing fluid to the milking cluster 102, from a manifold assembly 104. The manifold assembly 104 may deliver these fluids to the individual milking points 101 from common sources of supply provided by a fluid control unit 105 connected to the manifold assembly. The high pressure compressed air is typically at least 200KPa above atmospheric pressure. Electrical power for the control mechanisms 103c may be supplied by the common electrical control unit 109 via the cable 110. Each control mechanism 103c may have two fluid delivery lines 112, 113 that are connected to inlet nipples of a distributor device 111, and the distributor device 111 may be mounted on a clawpiece 106 of each milking cluster 102. The delivery line 112 may supply teat dip, for example, iodine and emollient, for sanitising the teat of a cow, whilst the delivery line 113 may supply flushing or disinfecting fluid for the teat cups, water and high pressure compressed air. The teat cups 1 of each milking cluster 102 may be connected via flexible short milk tubes 11 to the clawpiece 106 of the cluster where the milk extracted from the animal's teats may be collected and delivered by a flexible long milk tube 107 to a milk collection line 108 leading to a collection vessel of the equipment. As shown in the exploded diagram of Fig. 1 b, each distributor device 111 may be accompanied by a cavity distributor 111a that are connected to one another on the clawpiece 106. The distributor device 111 may receive the fluids from the delivery lines 112 and 113, and may have four outlets that distribute the fluids to the four teat cups 1 of the cluster via flexible short fluid tubes 16. The distributor device 111 may also be connected to the corresponding control mechanism 103c via a pneumatic control line 118, not shown in Fig. 1 a for clarity. The pneumatic control line 118 may be used to control valves of the distributor device 111 that control passage of fluids from the delivery lines 112 and 113 to the short fluid tubes 16. The teat cups 1 of each milking cluster 102 may be connected to outlets of the cavity distributor 111 a via flexible short air tubes 12. The cavity distributor 111a receives either differential pressure pulses or low pressure compressed air from the pulse lines 114 and 115, and has four outlets that distribute the differential pressure pulses or low pressure compressed air to the four teat cups 1 of the cluster via the flexible short air tubes 12. The control valve 103b may be controlled by the common electrical control unit 109 via the cable 110 to send to the pulse lines 114 and 115 either differential pressure pulses from pulsator 103a, or low pressure compressed air from the fluid control unit 105 via line 117. When the teat cups of a cluster 102 have been fitted to a cow's udder and the milking equipment is being operated in a milking cycle, vacuum may be applied through the long milk tube 107 and the clawpiece 106 to each short milk tube 11 in order to extract, from the associated teat cup, milk discharged into the liner from the engaged teat. The control valve 103b may be set to apply differential pressure pulses via the flexible short air tubes 12 to help stimulate release of milk from the cow’s teats. Once the flow of milk drops, indicating that the udder has been substantially fully milked, the control valve 103b may switch over to apply low pressure compressed air from the line 117 to the teat cups 1 via the flexible short air tubes 12, instead of differential pressure pulses, and the control mechanism 103c may apply teat dip to the teat cups via the delivery line 112, distributor 111 and short fluid tubes 16. The low pressure compressed air may seal the liners of the teat cups, to reduce any risk of the disinfectant reaching the short milk tubes 11, and the teat dip may remain at the heads of the liners to coat the teats as they are withdrawn from the liners. Once the teat cups 1 have been withdrawn from the udder, they fall into the inverted position shown in Fig. 1a, and any excess teat dip drains from the teat cups out of the heads of the liners. The stall control equipment 103 then applies rinsing liquid to the teat cups via the delivery line 113, distributor 111 and short fluid tubes 16 to rinse the liners of the teat cups in preparation for the next animal to be milked. The rinsing liquid may be supplied in pulses, interspaced with pulses of high pressure compressed air. The distributor device 111 will now be described in more detail with reference to Figs 2 to 11. Fig. 2 shows a schematic perspective diagram of the distributor device 111. The distributer device 111 may be formed as a single block having a front face 250 with inlet nipples and opposing side faces 252 and 254 with outlet nipples. The front face 250 may extend over a width dimension Wd and a height dimension He of the device, and each side face 252 and 254 may extend over a length dimension Ln and the height dimension He of the device. The inlet nipples may comprise a teat dip nipple 212 for connecting to the delivery line 112 and a rinsing fluid nipple 213 for connecting to the delivery line 113. The front face 250 may also have a pneumatic control nipple 218 for connecting to the pneumatic control line 118. The outlet nipples on the opposing side faces 252 and 254 may comprise four nipples 216 for connecting to the four short fluid tubes 16, respectively. Preferably there are two of the outlet nipples 216 on each of the two side faces 252 and 254. The inlet nipples 212 and 213 may extend perpendicular to the outlet nipples 216. The distributor device 111 may comprise a first unitary block of material 140 and a second unitary block of material 130 that is fitted into the first block of unitary material, and secured for example using screws 135, 136 and 137. The first unitary block of material may hold the inlet nipples 212 and 213 and outlet nipples 216, and the second block of unitary material may hold the pneumatic control nipple 218. The first and second unitary blocks of material 140 and 130 may for example be blocks of plastics material or resinous material for ease of manufacturing. An aperture 49 passes vertically through the first unitary block of material 140 along the height dimension He and may be used to secure the distributor 111 to the clawpiece 106. The schematic diagram of Fig 3 shows a plan view from above the distributor device 111, in which all four outlet nipples 216 can be seen. Fig. 4 shows a schematic side view of the distributor device 111. During the milking cycle, the distributor device 111 may be set in a closed configuration, in which any fluids directed into the inlet nipples 212 and 213 may be prevented from reaching the outlets 216, to avoid contaminating the milk. Figs. 5 to 7 show cross-sectional views of the distributor 111 when set in the closed configuration, as will now be described. The schematic diagram of Fig. 5 shows a cross-sectional view that is taken along line XSH1 shown in Fig. 4, in a generally horizontal plane through both the inlet nipples 212 and 213. As shown in Fig. 5, the first and second unitary blocks of material 130 and 140 may together provide a valve bore 35 extending along the length dimension Ln, and a first movable valve body 30 may be positioned in the valve bore 35 and able to slide longitudinally along the valve bore, defining a first valve. The first movable valve body 30 comprises a head end that may be fitted with an O-ring seal 31, and a tail end that may be fitted with a piston 36a. The piston 36a is secured to the movable valve body by a nut 36. In between the head end and the tail end, the first movable valve body 30 may be provided with an O-ring seal 34 for sealing against the inside surface of the valve bore 35. The first movable valve body may comprise a shaft with a bulbous head at the head end. The second unitary block of material 130 may define three distinct portions of the valve bore 35, a first portion which houses the piston 36a, a second narrower portion against which the O-ring seal 34 can seal, and a third portion that is wider than the second portion and that houses a spring 33 that is coiled around the movable valve body 30. The spring 33 may be under compression between the second narrower portion of the valve bore and the bulbous head of the first movable valve body 30, and so may urge the first movable valve body 30 rightwards as viewed in Fig. 5, into the closed configuration. An O-ring seal 32 may be positioned at an entrance to the part of the valve bore 35 that is formed within the second unitary block of material 130, and the O-ring seal 32 may be positioned around the spring 33. The first portion of the valve bore 35 and the piston 36a may together define a closed cavity 39, and a passageway 38 connects the closed cavity 39 to the pneumatic control inlet 218. The piston 36a may comprise an O-ring seal 35a that seals against the inside surface of the first portion of the valve bore 35. Compressed air may be inlet into the closed cavity 39 to drive the piston 36a against the bias of the spring 33 and move the first movable valve body 30 leftwards in the orientation as viewed in Fig. 5. The distributor device 111 may comprise an inlet manifold defined by two inlet passageways 21 and 22 and a first valve passageway 23. The two inlet passageways 21 and 22 may extend along the length dimension at opposing sides of the valve bore 35 and receive the two inlet nipples 212 and 213, respectively. The first valve passageway 23 may extend along the width direction, transverse to the valve bore 35 and the two inlet passageways 21 and 22, and the first valve passageway 23 may intersect with the valve bore 35 and the two inlet passageways 21 and 22 to allow transmission of fluids from the two inlet nipples 212 and 213 to the valve bore 35. The inlet passageway 22 is preferably fitted with a pressure-actuated non-return valve 22a to prevent back-flow of fluid from the distributor device into the inlet nipple 212. The non-return valve 22a may act to maintain the delivery line 112 primed with teat dip. The first valve passageway may be formed as a hole passing right through the second unitary body 140 between the side faces 252 and 254, and be closed at either end by ball bearings 23b. The second unitary body 140 may also define an upstream passageway 40 of an intermediate portion. The upstream passageway 40 may extend along the width dimension Wd of the distributor device, and may be in parallel with the first valve passageway 23, transverse to the valve bore 35. The upstream passageway 40 may also be formed as a hole 17 passing right through the second unitary body 140 between the side faces 252 and 254, and be closed at either end by ball bearings 40b. The upstream passageway 40 may intersect with the valve bore 35 to allow transmission of fluids from the valve bore 35 to the upstream passageway 40. The bulbous head of the first moveable valve body may comprise a sealing element in the form of the O-ring 31 at one end of the bulbous head, and a sealing element in the form of sealing surface 32a at an opposite end of the bulbous head. The part of the valve bore 35 that leads into the upstream passageway 40 may comprise a sealing element in the form of a sealing surface 31a. A proximate valve port may be defined between the sealing elements of the O-ring seal 32 and the sealing surface 32a, and a distal valve port may be defined between the sealing elements of the O-ring seal 31 and the sealing surface 31a. The sealing elements may be varied in alternate embodiments, for example both sealing elements of the bulbous head may be O-rings, or both sealing elements of the bulbous head may be sealing surfaces. The proximal valve port may control fluid flow from the first valve passageway 23 to the third portion of the valve bore 35, and the distal valve port may control fluid flow from the first valve passageway 23 to the upstream passageway 40. The bulbous head of the first moveable valve body 30 may open the proximal valve port and close the distal valve port when the first moveable valve body 30 is positioned in the closed configuration, as shown in Fig. 5. If the first moveable valve body 30 is moved to the open configuration then it may close the proximal valve port and open the distal valve port, for example as shown in Fig. 9. The O-ring 32 and sealing surface 32a may be spaced apart in the closed configuration allowing fluid flow through the proximal valve port, and the O-ring seal 31 and sealing surface 31a may be closed together in the closed configuration, blocking fluid flow through the distal valve port. If the second moveable valve body 50 is moved to the open configuration then it may close the proximal valve port and open the distal valve port, for example as shown in Fig. 10. The O-ring 32 and sealing surface 32a may be closed together in the open configuration, blocking fluid flow through the proximal valve port, and the O-ring seal 31 and sealing surface 31a may be spaced apart in the open configuration, allowing fluid flow through the distal valve port. It will be appreciated there is a point during the travel of the first movable valve body 30 from the closed configuration to the open configuration in which both the proximal and distal valve ports are open. The schematic diagram of Fig. 6 shows a cross-sectional view that is taken along line XSH2 shown in Fig. 4, in a generally horizontal plane through the outlet nipples 216. As shown in Fig. 6, the first and second unitary blocks of material 130 and 140 may together provide a valve bore 55 extending along the length dimension Ln, and a second movable valve body 50 may be positioned in the valve bore 55 and able to slide longitudinally along the valve bore, defining a second valve. The second movable valve body 50 comprises a head end that may be fitted with an O-ring seal 51, and a tail end that may be fitted with a piston 56a. The piston 56a is secured to the movable valve body by a nut 56. In between the head end and the tail end, the second movable valve body 50 may be provided with an O-ring seal 54 for sealing against the inside surface of the valve bore 55. The second movable valve body 50 may comprise a shaft with a bulbous head at the head end. The second unitary block of material 130 may define three distinct portions of the valve bore 55, a first portion which houses the piston 56a, a second narrower portion against which the O-ring seal 54 can seal, and a third portion that is wider than the second portion and that houses a spring 53 that is coiled around the movable valve body 50. The spring 53 may be under compression between the second narrower portion of the valve bore and the bulbous head of the first movable valve body 50, and so may urge the first movable valve body 50 rightwards as viewed in Fig. 6, into the closed configuration. An O-ring seal 52 may be positioned at an entrance to the part of the valve bore 55 that is formed within the second unitary block of material 130, and the O-ring seal 52 may be positioned around the spring 53. The first portion of the valve bore 55 and the piston 56a may together define a closed cavity 59, and a passageway 58 connects the closed cavity 59 to the pneumatic control inlet 218. The piston 56a may comprise an O-ring seal 55a that seals against the inside surface of the first portion of the valve bore 55. Compressed air may be inlet into the closed cavity 59 to drive the piston 56a against the bias of the spring 53 and move the first movable valve body 50 leftwards in the orientation as viewed in Fig. 6. The distributor device 111 may comprise an outlet manifold defined by two outlet passageways 61 and 62 and a second valve passageway 60. The two outlet passageways 61 and 62 may extend along the length dimension at opposing sides of the valve bore 55, and each outlet passageway may connect to two of the outlet nipples 216 positioned in the sides of the distributor device. The second valve passageway 60 may extend along the width direction, transverse to the valve bore 55 and the two outlet passageways 61 and 62, and the second valve passageway 60 may intersect with the valve bore 55 and the two inlet passageways 61 and 62 to allow transmission of fluids from the valve bore 55 to the outlet passageways 61 and 62. The second unitary body 140 may also define a downstream passageway 45 of the intermediate portion. The downstream passageway 45 may extend along the width dimension Wd of the distributor device, and may be in parallel with the second valve passageway 60, transverse to the valve bore 55. The downstream passageway 45 may intersect with the valve bore 55 to allow transmission of fluids from the downstream passageway 45 to the valve bore 55. The second valve passageway 60 may be formed as a hole passing right through the second unitary body 140 between the side faces 252 and 254, and be closed at either end by ball bearings 60b. The downstream passageway 45 may also be formed as a hole passing right through the second unitary body 140 between the side faces 252 and 254, and be closed at either end by ball bearings 45b. Ball bearings 61 b and 62b may also close off the ends of the two outlet passageways 61 and 62, respectively. The bulbous head of the second moveable valve body 50 may comprise a sealing element in the form of the O-ring 51 at one end of the bulbous head, and a sealing element in the form of sealing surface 52a at an opposite end of the bulbous head. The part of the valve bore 55 that leads into the second valve passageway 60 may comprise a sealing element in the form of a sealing surface 51a. A proximate valve port may be defined between the sealing elements of the O-ring seal 52 and the sealing surface 52a, and a distal valve port may be defined between the sealing elements of the O-ring seal 51 and the sealing surface 51a. The sealing elements may be varied in alternate embodiments, for example both sealing elements of the bulbous head may be O-rings, or both sealing elements of the bulbous head may be sealing surfaces. The proximal valve port may control fluid flow from the downstream passageway 45 to the third portion of the valve bore 55, and the distal valve port may control fluid flow from the downstream passageway 45 to the second valve passageway 60. The bulbous head of the second moveable valve body 50 may open the proximal valve port and close the distal valve port when the second moveable valve body 50 is positioned in the closed configuration, as shown in Fig. 6. The O-ring 52 and sealing surface 52a may be spaced apart in the closed configuration allowing fluid flow through the proximal valve port, and the O-ring seal 51 and sealing surface 51a may be closed together in the closed configuration, blocking fluid flow through the distal valve port. If the second moveable valve body 50 is moved to the open configuration then it may close the proximal valve port and open the distal valve port, for example as shown in Fig. 10. The O-ring 52 and sealing surface 52a may be closed together in the open configuration, blocking fluid flow through the proximal valve port, and the O-ring seal 51 and sealing surface 51a may be spaced apart in the open configuration, allowing fluid flow through the distal valve port. It will be appreciated there is a point during the travel of the second movable valve body 50 from the closed configuration to the open configuration in which both the proximal and distal valve ports are open. Fig. 7 shows a cross-sectional diagram that is taken along line XSV1 shown in Fig. 3, in a generally vertical plane, longitudinally through the centre of the device. The intersection of the valve bore 35 with the upstream passageway 40 and the intersection of the valve bore 55 with the downstream passageway 60 can be seen in Fig. 7. Also visible in Fig. 7 is a drain passageway 48 leading to a drain outlet 49 at the bottom of the device. The drain passageway 48 may extend downwardly from the third portion of the valve bore 55, transverse to both the valve bore 55 and the downstream passageway 60. In this embodiment the third portion of the valve bore 35 does not have any drain passageway leading from it, and so any fluid passing into that portion cannot travel onward beyond that portion. However, in an alternate embodiment the third portion of the valve bore 35 may be provided with a further drain passageway 48a similar to the drain passageway 48, which may lead to a further drain outlet at the bottom of the device similar to the drain outlet 49. This optional, further drain passageway 48a is illustrated schematically in Fig. 7. The further drain passageway 48a may feed into the drain outlet 49 rather than having its own dedicated drain outlet. In this embodiment the valve bores 35 and 55 are arranged one directly above the other, but they could alternatively be offset from one another in the width dimension, for example to make space for a drain passageway leading vertically downward from the third portion of the valve bore 35. Fig. 7 shows the distributor device in the closed configuration in which the proximal valve ports are open and the distal valve ports are closed, however the situation when the distributor device is moved to the closed configuration in which the proximal valve ports are closed and the distal valve ports are opened is shown in Fig. 11. Fig. 8 shows a cross-sectional diagram that is taken along line XSV2 shown in Fig. 3, in a generally vertical plane, longitudinally along the inlet passageway 21. The intermediate portion of the fluid path through the distributor device may provide two different branches for fluid flow from the valve bore 35 to the valve bore 55. Specifically, the intermediate portion may comprise the upstream passageway 40, the downstream passageway 45, and two linking passageways that may be transverse to the upstream and downstream passageways. One of the branches may be formed by half of the upstream passageway, one of the linking passageways, and half of the downstream passageway, and the other branch may be formed by the other half of the upstream passageway, the other linking passageway, and the other half of the downstream passageway. One of the linking passageways 42 is visible in Fig. 8, connecting from the upstream passageway 40 to the downstream passageway 45 on one side of the valve bores 35 and 55. The other linking passageway 43 (see Fig. 6) is parallel to the linking passageway 42, and also connects from the upstream passageway 40 to the downstream passageway 45, but at the other side of the valve bores 35 and 55 from the linking passageway 42. The provision of two separate branches for fluid flow through the intermediate portion helps ease the flow of fluid, however only one branch could be implemented in alternative embodiments if desired. Each linking passageway 42, 43 may extend diagonally in the length and height dimensions to make the distributor device more compact. Each linking passageway 42, 43 may extend from the upstream passageway to the downstream passageway and be downwardly slanted towards the front face 250, helping reduce the overall length of the distributor device. The linking passageways may be formed by moulding or drilling them into the first unitary body 140 from the bottom face 256 of the distributor device and closing off their ends at the bottom face 256 with ball bearings 42b. In use during the milking cycle, the teat dip delivery line 112 may be maintained primed by the non-return valve 22a and no fluids may be delivered to the distributor device by the delivery line 113 nor the pneumatic control line 118. Accordingly, the distributor device may be held in the closed configuration by the springs 33 and 53 driving the movable valve bodies 30 and 50 to seal the distal valve ports and open the proximal valve ports. In this state if any fluid is mistakenly sent to the distributor device along the delivery lines 112 or 113, for example due to a control system malfunction, then the fluid will be blocked from entering the upstream passageway 40 by the movable valve body 30. In the case where the third portion of the valve bore 35 is provided with a drain passageway and drain outlet, the fluid will be ejected from the drain outlet, providing a visible indication to the user than fluid has been mistakenly sent along the delivery lines 112 or 113 during the milking cycle. If fluid is mistakenly sent to the distributor device along the delivery lines 112 or 113 during the milking cycle, and if for any reason the first valve has failed and has not closed properly, then the fluid may pass through the intermediate portion to the valve bore 55. Here, the second movable valve body in the closed configuration prevents the fluid from travelling through the distal valve port and onwardly to the outlet manifold, and provides an additional level of safety. Instead, the fluid flowing into the valve bore 55 may be routed to the drain passageway 48 and drain outlet 49, providing a visual indication to the user that a malfunction has occurred. At the end of the milking cycle, the stall control equipment 103 may send compressed air along the pneumatic control line 118 to move the distributor device into the open configuration. The compressed air enters the distributor device through the pneumatic control inlet 218, and may be conveyed into the closed cavities 39 and 59 via the passageways 38 and 58, respectively. The rising pressure in the closed cavities forces the pistons 36a and 56a and therefore the first and second movable valve bodies 30 and 50 against the biases of the springs 33 and 53, moving the first and second movable valve bodies 30 and 50 into the open configuration. In the open configuration, the proximal valve ports are closed and the distal valve ports are open, allowing fluids sent to the distributor device along the delivery lines 112 or 113 to be conveyed from the inlet manifold to the outlet manifold, and out of the outlet nipples 216, onward to the teat cups. Since the proximal valve ports are closed, the fluid does not escape through the drain passageway(s). Typically, teat dip is sent through the distributor to the teat cups, followed by rinsing fluids and compressed air. During this process, the stall control equipment 103 may toggle the distributor device between the open and closed configurations by sending compressed air via the pneumatic control line 118. For example, the distributor device may be moved to the open configuration whilst teat dip is sent to the teat cups via the distributor, then moved to the closed configuration whilst the teat cups are removed from the animal, then moved to the open configuration whilst rinsing fluid followed by compressed air is sent to the teat cups via the distributor, then moved to the closed configuration, then moved to the open configuration again whilst another cycle of rinsing fluid followed by compressed air is sent to the teat cups via the distributor, and then moved to the closed configuration again. Further cycles of rinsing fluid followed by compressed air may be sent subsequently, including moving between the open and closed configurations. Since the drain outlet is open to the external environment, the drain outlet and drain passageway should be cleaned to guard against ingress of any dirt or debris that could either cause a blockage or be fed to the teat cups. The drain passageway and the drain outlet cannot be flushed with fluid to clean it when the distributor device is in the open or closed configurations, because when the proximal valve port (of the second valve) to the drain passageway is open in the closed configuration, the distal valve port (of the first valve) to the first valve bore is closed and so no fluid can flow through the intermediate portion to the second valve and therefore to the drain passageway. As noted earlier, there is a point during the travel of the movable valve bodies from the closed configuration to the open configuration in which both the proximal and distal valve ports of each valve are open at the same time, and therefore a short time period in which fluid inlet to the distributor can pass though the distal valve port of the first valve and then out the proximal valve port of the second valve to the drain passageway. Performing repeated cycles of rinsing fluids as described above helps wash the drain passageway and the drain outlet with the rinsing fluids. The distributor device may also be repeatedly cycled between open and closed configurations whilst continuously passing rinsing fluids through the distributor to wash the drain passageway and the drain outlet with the rinsing fluids, for example at a cycle rate of at least 1 Hz. Many other variations of the described embodiments falling within the scope of the invention will be apparent to those skilled in the art.

Claims

1. A distributor device for distributing fluid to teat cups of a milking cluster, the distributor device comprising an inlet manifold, an outlet manifold, a drain outlet, a drain passageway leading to the drain outlet, a fluid path configured to pass fluids from the inlet manifold to the outlet manifold, and first and second valves arranged in series along the fluid path, the first valve comprising a first movable valve body and the second valve comprising a second movable valve body, wherein the fluid path comprises an intermediate portion between the first and second valves, the first and second valves having a closed configuration in which the first movable valve body is positioned to block fluid flow from the inlet manifold to the intermediate portion and the second movable valve body is positioned to block fluid flow from the intermediate portion to the outlet manifold and to allow fluid flow from the intermediate portion to the drain passageway, the first and second valves having an open configuration in which the first movable valve body is positioned to allow fluid flow from the inlet manifold to the intermediate portion and the second movable valve body is positioned to allow fluid flow from the intermediate portion to the outlet manifold and to block fluid flow from the intermediate portion to the drain passageway.

2. The distributor device of claim 1, wherein the first valve comprises a valve bore, wherein the first movable valve body is slidable along the valve bore to transition between the open and closed configurations.

3. The distributor device of claim 2, wherein the first valve comprises a valve port, the valve port leading from the valve bore into the intermediate portion, and wherein the first movable valve body is configured to slide along the valve bore to the valve port to block the valve port in the closed configuration.

4. The distributor device of claim 2 or 3, wherein the inlet manifold leads into the valve bore.

5. The distributor device of any preceding claim, wherein the second valve comprises a valve bore, wherein the second movable valve body is slidable along the valve bore to transition between the open and closed configurations.

6. The distributor device of claim 5, wherein the second valve comprises a first valve port, the first valve port leading from the valve bore of the second valve into the outlet manifold, wherein the second movable valve body is configured to slide along the valve bore to the first valve port to block the first valve port in the closed configuration.

7. The distributor device of claim 5 or 6, wherein the second valve comprises a second valve port, the second valve port leading from the valve bore of the second valve into the drain passageway, wherein the second movable valve body is configured to slide along the valve bore to the first valve port to open the second valve port in the closed configuration.

8. The distributor device of claim 5, 6, or 7, wherein the intermediate portion leads into the valve bore of the second valve.

9. The distributor device of any preceding claim, wherein the first and second valves comprise one or more springs that urge the first and second movable valve bodies into the closed configuration of the valves.

10. The distributor device of any preceding claim, wherein the first and second movable valve bodies comprise one or more piston surfaces configured to be driven pneumatically to control movement of the first and second movable valve bodies.

11. The distributor device of any preceding claim, comprising a pneumatic control inlet configured to receive compressed air for controlling movement of both the first and second movable valve bodies and whether the valves are moved into the open or the closed configuration.

12. The distributor device of any one of claims 3 to 11 when dependent on at least claim 2, wherein the inlet manifold comprises two inlets connected to two respective inlet passageways, the inlet passageways leading from the inlets towards the valve bore of the first valve.

13. The distributor device of claim 12, wherein the inlet manifold comprises a first valve passageway that is transverse to the valve bore of the first valve and intersects with the valve bore of the first valve, wherein the inlet passageways are both connected to the first valve passageway.

14. The distributor device of claim 13, wherein the two inlet passageways are connected to the first valve passageway at opposing sides of the first valve to one another.

15. The distributor device of any one of claims 4 to 14 when dependent on at least claim 3, wherein the valve port of the first valve leads into an upstream passageway of the intermediate portion, the upstream passageway being transverse to the valve bore of the first valve and intersecting with the valve bore of the first valve.

16. The distributor device of any one of claims 9 to 15 when dependent on at least claim 8, wherein the intermediate portion comprises a downstream passageway leading into the valve bore of the second valve, the downstream passageway being transverse to the valve bore of the second valve and intersecting with the valve bore of the second valve at a location in between the first and second valve ports of the second valve.

17. The distributor device of claim 16 when appended to claim 15, wherein the intermediate portion comprises two linking passageways, each linking passageway extending from the upstream passageway to the downstream passageway, wherein the two linking passageways are at opposing sides of the first valve from one another and at opposing sides of the second valve from one another.

18. The distributor device of any one of claims 7 to 17 when dependent on at least claim 6, wherein the outlet manifold comprises a second valve passageway that is transverse to the valve bore of the second valve and intersects with the valve bore of the second valve, and wherein the first valve port of the second valve leads into the second valve passageway.

19. The distributor device of claim 18, wherein the outlet manifold comprises two outlet passageways intersecting with the second valve passageway, wherein the intersection of the second valve passageway with the valve bore of the second valve is in between the intersections of the second valve passageway with the two outlet passageways.

20. The distributor device of any preceding claim, wherein the distributor device comprises a first unitary block of material that defines the inlet manifold, the outlet manifold and the intermediate portion.

21. The distributor device of claim 20, wherein the distributor device comprises a second unitary block of material that is fitted into the first block of unitary material, wherein the second unitary block of material at least partially houses the first and second movable valve bodies.

22. The distributor device of any preceding claim, wherein the distributor device comprises the first and second valves positioned one above the other in parallel, and two inlet nipples positioned on opposing sides of the valves from one another.

23. The distributor device of any preceding claim, wherein upon transitioning from the closed configuration to the open configuration, the first movable valve body is configured to allow fluid flow from the inlet manifold to the intermediate portion before the second movable valve body has moved so far as to block fluid flow from the intermediate portion to the drain passageway.

24. A milking cluster comprising a clawpiece and teat cups connected to the clawpiece, wherein the distributor device of any preceding claim is mounted on theclawpiece, and wherein fluid lines are connected from the outlet manifold of the distributer device to the teat cups for delivering fluids to the teat cups.

25. Milking equipment comprising the milking cluster of claim 24 or the distributor device of any one of claims 1 to 23, the milking equipment further comprising control equipment configured to control the positions of the first and second movable valve bodies and the fluids that are sent to the inlet manifold, wherein the control equipment is configured to send fluids to the inlet manifold whilst repetitively cycling the valves between the open and closed configurations at a cycle rate of at least 1 Hz.

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