A liquid mixing station

Abstract

There is provided a liquid mixing station, comprising a controller, a vacuum generator and at least two liquid sources for supplying respective liquids that are to be mixed with one another. At least one of the liquid sources is a source container for storing a respective liquid to be mixed. The source container comprises a vacuum port for supplying a vacuum from the vacuum generator into the source container, a liquid inlet for sucking liquid from a bulk container, and a vacuum sensor for sensing a level of vacuum inside of the source container. The vacuum sensor is connected to the controller and the controller is configured to determine a level of liquid remaining in the bulk container based on a level of vacuum sensed by the vacuum sensor.

Description

[0001] A LIQUID MIXING STATION

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a liquid mixing station, for example for mixing a teat dip, which may be applied to a teat of an animal after milking.

[0004] BACKGROUND OF THE INVENTION

[0005] Milking an animal typically includes inserting a teat of the animal into a teat cup which applies a vacuum to assist in extraction of milk. After milking, a teat dip liquid is typically applied to the teat, and the teat dip typically comprises disinfectants and emollients to protect the teat from infection and to keep the skin of the teat in good condition. If teats fall into poor condition, then infections such as Mastitis can result, sometimes leading to the death of the animal. Keeping the teats in good condition is therefore of utmost importance.

[0006] Each animal only requires a small quantity of teat dip at each milking, however teat dip is typically mixed by a distributor or manufacturer in advance, and shipped to farms in bulk. It is possible to order teat dips with higher or lower concentrations or ratios of active ingredients to suit the farmer requirements, however since large quantities are typically delivered to farms in bulk, the mix cannot be changed on a day-to-day basis.

[0007] Since a large proportion of the teat dip is simply water, if the teat dip could be mixed on-site at the farm then only the other ingredients would need to be shipped and a large proportion of the delivery costs could be avoided. The mix can also be more easily altered since smaller quantities can be made up than those usually delivered to farms.

[0008] WO 2011 / 059477 A2 discloses pumping teat dip ingredients into a mixing manifold for mixing up teat dip at the farm, to reduce delivery costs. This means that teat dip can be made in smaller quantities at the desired concentration and mix ratios, however the metering and mixing of the various ingredients isproblematic and a dip quality sensor is used to signal an alarm if the mixed teat dip is outside of a predetermined specification. The ingredients are stored in tanks. Small tanks are inconvenient because they require frequent monitoring and refilling by the farmer. Large tanks typically mean there is a large height difference between the level of the ingredient in the tank when the tank is full and when the tank is almost empty, resulting in variances in the amount of ingredient that is pumped from the tank.

[0009] It is therefore an object of the invention to improve on the known art.

[0010] SUMMARY OF THE INVENTION

[0011] According to a first aspect of the invention, there is provided a liquid mixing station as defined in claim 1. The liquid mixing station comprises a controller, a vacuum generator and at least two liquid sources for supplying respective liquids that are to be mixed with one another. At least one of the liquid sources is a source container for storing a respective liquid to be mixed. The source container comprises a vacuum port for supplying a vacuum from the vacuum generator into the source container, a liquid inlet for sucking liquid from a bulk container, and a vacuum sensor for sensing a level of vacuum inside of the source container, wherein the vacuum sensor is connected to the controller and wherein the controller is configured to determine a level of liquid remaining in the bulk container based on a level of vacuum sensed by the vacuum sensor.

[0012] The use of both a bulk container and a source container for storing the liquid from the bulk container means that the bulk container can be made relatively large so that it does not require regular replacement or refilling, and that the source container can be made relatively small so that there is less height variation in the level of the liquid in the source container. Furthermore, the use of a vacuum generator to draw liquid from the bulk container into the source container and the sensing of the level of vacuum inside the source container allows the controller to determine a level of liquid remaining in the bulk container, and therefore when the bulk container requires replacement or replenishment. The determined level of the liquid remaining in the bulk container may be substantially zero, or empty.If the bulk container is open to the atmosphere, then the controller may be configured to determine there is an empty level of liquid (i.e. no liquid) remaining in the bulk container when the level of vacuum inside the source container falls below an empty threshold level, since air from the atmosphere rushes into the bulk container and then into the source container very rapidly, causing a large drop in the vacuum inside the source container.

[0013] The liquid inlet may suck the liquid from the bulk container via a passageway, and the passageway may comprise a pipe having an opening at the bottom of the bulk container. If the bulk container is open to the atmosphere, then air may enter the pipe through the opening once the bulk container has been emptied, resulting in the drop in the level of vacuum.

[0014] Alternatively, if the bulk container is not open to the atmosphere then the controller may be configured to determine there is an empty level of liquid in the bulk container when the level of vacuum inside the source container increases above an empty threshold level, since no further liquid can enter the source container from the bulk container, causing an increase in the level of the vacuum inside the source container.

[0015] When there is a lower level of liquid inside the bulk container, the vacuum in the source container may be at a higher level, or in other words further beneath atmospheric pressure, in order to draw the liquid in the bulk container up through the greater height difference between lower level of the liquid in the bulk container and the liquid inlet of the source container. Conversely, when there is a higher level of liquid inside the bulk container, the vacuum in the source container may not rise to such a high level, or in other words not so far beneath atmospheric pressure, in order to draw the liquid in the bulk container up through the lesser height difference between higher level of the liquid in the bulk container and the liquid inlet of the source container. Accordingly, the level of vacuum inside the source container may depend on how far the liquid has to be lifted by the vacuum before the liquid enters the source container, and so the level of the vacuum may be used to measure how much liquid remains in the bulk container.Determining the level of liquid remaining in the bulk container may be used to determine a rate of consumption of the liquid, and / or to predict how long is left before the bulk container will need to be replenished with liquid or replaced with a new bulk container.

[0016] The liquid mixing station may comprise a valve arrangement connected between the liquid inlet and the bulk container, the valve arrangement configured to open and close the passageway leading from the bulk container to the liquid inlet. Thus the flow of liquid from the bulk container to the source container can be shut off if desired.

[0017] The valve arrangement may be configured to open and close a passageway leading from a further bulk container to the liquid inlet, so that liquid can be drawn from either the bulk container or the further bulk container. This allows the bulk container to be replaced once empty, without interrupting availability of the liquid because the liquid can be drawn from the further bulk container instead.

[0018] The controller may be configured to control the valve arrangement to open the passageway from the bulk container to the liquid inlet or open the passageway from the further bulk container to the liquid inlet in dependence on the level of vacuum sensed by the vacuum sensor. Accordingly, once the controller determines the bulk container has been emptied of liquid based on the sensed level of vacuum, the valve arrangement may be switched by the controller to draw liquid from the further bulk container instead of the bulk container. Then the bulk container can be replaced or replenished whilst the liquid is available to be drawn from the further bulk container instead.

[0019] The valve arrangement may be controlled by the controller to supply the liquid to the source container from only one of the bulk container and the further bulk container at a time, to ensure that consistent levels of vacuum can be achieved in the source container.The controller may be configured to issue a notification that the level of liquid remaining in the bulk container has fallen to empty. The notification may alert a farmer that new liquid or a new bulk container needs to be ordered, before the further bulk container is emptied as well, to ensure that liquid for supply to the source container is continuously available.

[0020] The valve arrangement may be configured to open and close a further passageway leading from the bulk container to the liquid inlet. The liquid inlet may suck the liquid from the bulk container via the further passageway, and the further passageway may comprise a further pipe having a further opening intermediate of the top and the bottom of the bulk container, at a level corresponding to a depletion level. The controller may be configured to compare the level of vacuum sensed by the vacuum sensor to a depletion threshold level whilst the further passageway is open, to determine whether the level of liquid has dropped to the depletion level. If the bulk container is open to the atmosphere, then air may enter the further pipe through the further opening once the level of liquid in the bulk container has dropped to the depletion level, resulting in the drop in the level of vacuum.

[0021] The controller may be configured to issue a notification that the level of liquid remaining in the bulk container has fallen beneath a depletion level based on the level of vacuum sensed by the vacuum sensor. The depletion level of liquid may be a higher level of liquid than the empty level of liquid.

[0022] The source container may comprise a depletion level sensor configured to sense when the level of liquid in the source container has fallen to a depletion level, wherein the depletion level sensor is connected to the controller, and wherein the controller is configured to activate supply of a vacuum from the vacuum generator into the source container in response to a depletion signal from the depletion level sensor indicating that the level of liquid in the source container has fallen to the depletion level. Accordingly, whenever the source container has been depleted to a certain level, it can be automatically re-filled from the bulk container.The source container may comprise a fill level sensor configured to sense when the level of liquid in the source container has risen to a fill level. The fill level sensor may be connected to the controller and the controller may be configured to deactivate supply of a vacuum from the vacuum generator into the source container in response to a fill signal from the fill level sensor indicating that the level of liquid in the source container has risen to the fill level. Accordingly, once the source container has been re-filled to a certain level, the vacuum can be automatically deactivated to prevent over-filling of the source container.

[0023] The source container may also comprise an emergency level sensor configured to sense when the level of liquid in the source container has risen above the fill level to an emergency level. The emergency level sensor may be connected to the controller and the controller may be configured to signal an alarm in response to an emergency signal from the emergency level sensor indicating that the level of the liquid in the source container has risen to the emergency level. Therefore, in the event of a malfunction, for example a malfunction of the fill level sensor, an alarm will be signalled to alert the farmer that there is a problem. The controller may also deactivate supply of a vacuum from the vacuum generator into the source container in response to the emergency signal to prevent further overfilling of the source container.

[0024] The controller may be configured to measure the level of vacuum in the source container once the vacuum generator has been activated to generate a vacuum and once the valve arrangement has been switched to open a passageway between the bulk or further bulk container and the source container. The controller may be configured to measure the level of vacuum after a delay period of time has elapsed from the activation of the vacuum generator and / or the opening of the passageway so that the measurement is taken whilst the liquid is flowing into the source container from the bulk or further bulk container.

[0025] The liquid mixing station may comprise a compressed air source, and the compressed air source may be connected to the vacuum generator. The vacuum generator may comprise a passageway for carrying the compressed air and a venturi hole into the passageway for generating the vacuum. Accordingly, there isno need to supply a vacuum to the liquid mixing station, and the vacuum can instead be generated from a source of compressed air. The determination of the level of the liquid in the bulk container is based on the level of vacuum, and so forming the vacuum generator as part of the liquid mixing station allows the vacuum to be better controlled than if an external source of vacuum was used. The compressed air source may for example be an inlet for receiving compressed air from an external supply. The compressed air may be at a particular pressure, to generate a particular vacuum at the vacuum generator.

[0026] The liquid mixing station may comprise an air valve arrangement configured to open and close a passageway from the compressed air source to the vacuum generator, and the controller may be configured to activate the supply of vacuum from the vacuum generator into the source container by controlling the air valve arrangement to open the passageway. Conversely, the controller may be configured to deactivate the supply of the vacuum from the vacuum generator into the source container by controlling the air valve arrangement to close the passageway. Thus, the vacuum generator may only be operated to produce a vacuum when the controller determines that liquid is to be drawn into the source container from the bulk or further bulk containers.

[0027] The liquid mixing station may comprise a mixing vessel and at least one pump for pumping the liquids from the liquid sources into the mixing vessel. The mixing vessel may allow mixing and storage of the respective liquids for later use. Alternatively, if each liquid source has a respective pump then the liquids may be mixed within a manifold connected between the outputs of the pumps and the mixing vessel. The at least one pump may be a diaphragm pump with a diaphragm that is driven by compressed air from the same compressed air source as used for the vacuum generators.

[0028] The source container may be a first source container, the first source container being a first one of the at least two liquid sources. The liquid mixing apparatus may also comprise a second source container being a second one of the at least two liquid sources. The second source container may be a same type of container as the first source container, and so the second source container maycomprise a vacuum port for supplying a vacuum into the second source container, a liquid inlet for receiving a liquid from an additional bulk container in which the liquid is held, and a vacuum sensor for sensing a level of vacuum inside of the second source container. The vacuum sensor may be connected to the controller and the controller may be configured to determine a level of liquid remaining in the additional bulk container based on a level of vacuum sensed by the vacuum sensor of the second source container. The control of the liquid drawn into the second source container from the additional bulk container may be the same as the control of the liquid drawn into the first source container from the bulk container.

[0029] The first source container and the second source container may be arranged at a same height as one another within a housing of the liquid mixing station, and so similar vacuum levels in the first and second source containers correspond to similar liquid levels in the bulk and additional bulk containers, respectively, so that a mapping stored in the controller between the vacuum level in the first source container and the liquid level in the bulk container is also valid for mapping between the vacuum level in the second source container and the liquid level in the additional bulk container.

[0030] The vacuum generator may be a first vacuum generator and the liquid mixing station may comprise a second vacuum generator configured to supply a vacuum to the vacuum port of the second source container. The air valve arrangement may be controlled by the controller to supply the compressed air to the first vacuum generator or to the second vacuum generator, depending on whether the first source container or the second source container is to be filled. The controller may control the air valve arrangement to only supply one of the first vacuum generator and the second vacuum generator with compressed air at a time, so that the first vacuum generator and the second vacuum generator are not activated simultaneously.

[0031] The compressed air source is an inlet for compressed air, and the inlet may be connected to an air filter for filtering the compressed air prior to the compressed air entering the vacuum generator. Thus, the filter prevents any particles fromentering the vacuum generator and negatively affecting the performance of the vacuum generator or from entering the source container.

[0032] The liquid mixing station may be a teat dip station for mixing teat dip, and the liquid held by the source container may for example be disinfectant and / or emollient for mixing with water or another solvent to produce the teat dip. The first source container may hold disinfectant, the second source container may hold emollient, and a third one of the liquid sources may be an inlet for connection to a mains water supply.

[0033] There is further provided an apparatus comprising the liquid mixing station, the bulk container and a pipe leading from the bulk container into the liquid mixing station for conveying liquid from the bulk container to the liquid mixing station. The bulk container may be positioned at a lower height than the source container of the liquid mixing station to provide a reliable indication of the level of the liquid in the bulk container based on the level of vacuum in the source container.

[0034] The volume of the bulk container may be at least five times greater than the volume of the source container, so that the source container can be re-filled multiple times from the bulk container before the bulk container needs to be replaced or replenished.

[0035] DETAILED DESCRIPTION

[0036] Embodiments of the invention will now be described by way of non-limiting example only and with reference to the accompanying drawings, in which:

[0037] Fig. 1 shows a schematic perspective diagram of a liquid mixing station according to an embodiment of the invention, including a housing with source and storage vessels mounted on opposing sides of the housing to one another;

[0038] Fig. 2 shows a schematic perspective diagram of the liquid mixing station of Fig. 1 with a front door opened to show various internal components;

[0039] Fig. 3 shows a schematic side elevational diagram of the liquid mixing station of Fig. 1, with the front door removed and the source and storage vesselsshown as transparent;

[0040] Fig. 4 shows a schematic diagram of various liquid connections to and within the liquid mixing station of Fig. 1 ;

[0041] Fig. 5 shows a flow diagram of a method implemented by the liquid mixing station of Fig. 1 ;

[0042] Fig. 6 shows a schematic diagram of an apparatus comprising the liquid mixing station of Fig. 1 and bulk containers for liquids connected to the liquid mixing station; and

[0043] Fig. 7 shows a schematic diagram of a pump forming part of the liquid mixing station of Fig. 1.

[0044] The figures are not to scale, and same or similar reference signs denote same or similar features.

[0045] Fig. 1 shows a liquid mixing station 100 in accordance with an embodiment of the invention. The liquid mixing station may comprise a housing 50 having a top panel 51, a left side panel 52, right side panel 53, and front door 55. The housing 50 may also have a rear panel 50a opposite from the front door 55, and a bottom panel 54 (see Fig. 2) opposite from the top panel 51. In this embodiment the housing 50 is generally rectangular, although other shapes of housing could alternatively be implemented.

[0046] The front door 55 may be connected to the left side 52 with hinges, and may comprise a locking mechanism 55a to hold the front door 55 closed. A source vessel 1 may be mounted to the left side 52 of the housing, and a storage vessel 4 may be mounted to the right side 53 of the housing. In use, the liquid mixing station is typically wall-mounted, for example by fixing the rear panel 50a to a wall at a convenient height.

[0047] Fig. 2 shows a perspective view of the liquid mixing station 100 with the front door 55 hinged open, allowing various components inside of the housing 50 to be seen. The liquid mixing station may have a transceiver 57 mounted on the rear side of the front panel 55, and the transceiver may have one or more antenna 57a for wireless communicating with external networks. For example, thetransceiver 57 may include a SIM card for connecting to a cellular telecommunications network, or may connect to local wireless network having an Internet connection, and / or through direct wireless links such as Bluetooth®, or any other known wireless communication methods.

[0048] The transceiver 57 may connect to a cloud-based server computer 120 via the Internet, and access a weather forecasting service provided by the server computer 120, for retrieval of weather forecast data. The transceiver 57 may also connect to a remote computer 122, which may for example be a smartphone device. In some embodiments, the transceiver 57 may retrieve the weather forecast data from the server computer 120 via the remote computer 122.

[0049] The liquid mixing station may also have a controller 56 mounted on the rear side of the front panel 55 and connected to the transceiver 57. The controller 56 may monitor and / or control various functions of the liquid mixing station 100, typically via electrical wires (not shown for clarity) that cross from the front door 55 to the left side panel 52 at a front edge of the left side panel 52. The controller 56 may record the geographic location of the liquid mixing station, for example in a memory of the controller. The geographic location may be programmed into the memory of the liquid mixing station, or the liquid mixing station may utilise satellite or cellular base station signals from the transceiver to determine the geographical location of the mixing station.

[0050] The housing 50 may enclose a pump 5 and two liquid sources in the form of first and second source containers 2 and 3. The source containers 2 and 3 may be used to store two different types of liquid to be mixed with one another, for example disinfectant and emollient. The source containers 2 and 3 may be held within the housing 50 at a same height as one another, as shown.

[0051] The pump 5 may be used to pump the liquids from the source vessel 1 and from the source containers 2 and 3 into the storage vessel 4, to mix the liquids together. Typically the source vessel 1 is used to store water, which dilutes the disinfectant and emollient liquids so they can be held in the source containers 2 and 3 in a more concentrated form. The storage vessel 4 comprises a overflow 47in case of a malfunction that pumps excessive liquids into the storage vessel. The overflow 47 may be on the right side of the storage vessel 4, so that any liquid exiting through it is clearly visible and will alert the farmer to the malfunction.

[0052] The source containers 2 and 3 may be the same as one another, and may each include a sensing arrangement of one or more sensors to detect the level of the liquid stored inside of them. Each source container may include a depletion level sensor 39, a fill level sensor 40 and an emergency level sensor 41. The depletion level sensor 39, fill level sensor 40 and emergency level sensor 41 may be float sensors that sense when the liquid level in the source container is above or below the sensor. Accordingly, the depletion level sensor 39 may be at a depletion level within the source container, the fill level sensor 41 may be at a fill level within the source container, above the depletion level sensor 39, and the emergency level sensor 41 may be at an emergency level within the source container, above both the depletion and fill level sensors 39 and 40.

[0053] The depletion level sensor 39, fill level sensor 40 and emergency level sensor 41 may all be connected to a header connector 46, and the header connector 46 may be connected to the controller 56 via a cable (not shown in Figs). Thus, the controller 56 may monitor the level of the liquid in each source container using the depletion level sensor 39, fill level sensor 40 and emergency level sensor 41.

[0054] The source containers 2 and 3 may also each include a vacuum sensor 45 for detecting a level of vacuum inside the source container. The vacuum sensor 45 may be connected to the header connecter 46, and so the header connector 46 may also provide information on any vacuum inside the source containers to the controller 56.

[0055] The source containers 2 and 3 may each include an outlet port 42, an inlet port 43, and a vacuum port 44. The outlet port 42 may be at the top of the source container and include a straw inside the source container that reaches down to near the base of the source container, allowing liquid to be drawn from the source container via the outlet port. The inlet port 43 may also be at the top of the sourcecontainer and allows liquid to be added to the source container. The vacuum port 44 is may be at the top of the source container, so that no liquid will flow out of the source container through the port 44 when a vacuum is applied. The liquid may be drawn into the source container via the inlet port 43, by applying a vacuum inside the source container using the vacuum port 44.

[0056] Fig. 3 shows a more comprehensive view of the components inside the housing 50 of the liquid mixing station 100, with the front door 55 removed and the source and storage vessels 1 and 4 made transparent so their internals are visible. The components are connected by various liquid pipes, as shown schematically in Fig. 4.

[0057] Referring to Fig. 3, the source vessel 1 may comprise a float valve 26 for inletting liquid into the source vessel. The float valve 26 may be connected to a pipe leading to one of several connections 37 at the bottom panel 54 of the housing. That connection 37 may for example be connected to a mains water supply pipe, and so water from the mains water supply 111 (see Fig. 4) may be delivered into the source vessel 1 under control of the float valve 26. The float valve 26 may comprise a float 27 which falls and rises with the liquid level in the source vessel 1 , respectively opening and closing the float valve to maintain the level of the liquid in the source vessel 1.

[0058] The source vessel 1 may also comprise an emergency level sensor 32 beneath the float valve 26. The emergency level sensor may comprise a small float that is pivotally connected to a base, as shown, and the float will pivot up or down depending on the liquid level. The level sensors 39, 40 and 41 of the source containers 2 and 3 may be the same type of sensor as the emergency level sensor 32. The emergency level sensor 32 may detect when the level of liquid inside the source vessel falls below the emergency level sensor, corresponding to an emergency level. The emergency level sensor 32 may be connected to the controller 56 and the controller 56 may sound an alarm and / or issue a notification to the remote computer 122 if the liquid falls below the emergency level, signifying that a malfunction has occurred.The source vessel 1 may comprise an outlet 33 for outletting liquid from the source vessel 1 , and the outlet 33 may be beneath the emergency level sensor 32 so the emergency is signalled before the liquid has fallen so far as to interrupt supply to liquid to the outlet 33. The outlet 33 is connected to a valve arrangement 6 via a pipe 11 , also as seen in Fig. 4.

[0059] The valve arrangement 6 comprises multiple valves which are controlled by the controller 56 and which direct the flow of liquids through the liquid mixing station 100. Referring to Fig. 4, the liquids to be mixed are first drawn into the source containers (header tanks) 2 and 3, from bulk containers in bulk storage 112 and 113. The bulk containers are separate from the liquid mixing station, and are typically positioned beneath the liquid mixing station, and connected to the liquid mixing station at connections 37.

[0060] Two bulk containers at bulk storage 112 may be connected to two connections 37, and the liquid mixing station may comprise two pipes 16 and 17 that lead from those connections 37 to a valve block 6a of the valve arrangement 6. The valve block 6a may also be connected to the inlet port 43 of the source container 2 via a pipe 18, and the valve block 6a may open and close passageways from the pipes 16 and 17 to the pipe 18 under control of the controller 56, to allow delivery of liquid from the bulk storage 112 to the source container 2.

[0061] Similarly, two bulk containers at bulk storage 113 may be connected to two connections 37, and the liquid mixing station may comprise two pipes 21 and 22 that lead from those connections 37 to a valve block 6b of the valve arrangement 6. The valve block 6b may also be connected to the inlet port 43 of the source container 3 via a pipe 23, and the valve block 6b may open and close passageways from the pipes 21 and 22 to the pipe 23 under control of the controller 56, to allow delivery of liquid from the bulk storage 113 to the source container 2.

[0062] The liquids may be drawn along the pipes 16, 17, 18 and 12, 22, 23 by vacuums inside of the source containers 2 and 3, the vacuums being applied viathe vacuum ports 44 of the source containers. The vacuums are generated by vacuum generators 7 and 8, and the vacuum generators are driven by compressed air, as will now be explained in more detail.

[0063] The liquid mixing station may comprise an air valve block 29, which may be connected to an air supply 110 of compressed air via the connections 37. The air valve block 29 may comprise a first air filter 28, and second air filter 30, and a silencer 31. The first air filter may be a relatively coarse air filter, for example a 5 micron filter, and the second air filter may be a relatively fine air filter connected to the output of the coarse air filter, for example a 0.1 micron filter. The silencer serves to reduce any noise generated by the flow of the compressed air.

[0064] The air valve block 29 may also comprise an air valve for opening and closing a passageway for compressed air, the passageway leading to the valve arrangement 6 via a pipe, more specifically leading to a valve block 6c of the valve arrangement 6 via the pipe. The air valve may be connected to the controller 56, and the controller 56 may control the air valve to open and close as required. The air valve block 29 and the valve block 6c may together constitute an air valve arrangement.

[0065] The valve block 6c may be connected to the vacuum generator 7 by a pipe 19, and also connected to the vacuum generator 8 via a pipe 24. The valve block 6c may open and close passageways from the air valve block 29 to pipes 19 and 24 under control of the controller 56, to allow delivery of compressed air from the compressed air supply 110 to the vacuum generators 7 and 8. Each vacuum generator may comprise a passageway for compressed air and a venturi hole which opens into that passageway to generate a vacuum. The vacuum generated by vacuum generator 7 may be supplied to the vacuum port 44 of the source container 2 by a pipe 20, and the vacuum generated by vacuum generator 6 may be supplied to the vacuum port 44 of the source container 3 by a pipe 25.

[0066] When the source container 2 becomes depleted of liquid to the depletion level, the depletion level sensor 39 of the source container 2 may indicate to the controller 56 that the liquid has fallen to the depletion level. In response to thatindication, the controller 56 may open a valve in valve block 6a to open a passageway either along pipes 16 and 18 or 17 and 18, and open a valve in valve block 6c to open a passageway from the air valve block 29 to the vacuum generator 7. Compressed air may enter the vacuum generator 7 and a vacuum may be applied along the pipe 20 and into the source container 2 via the vacuum port 44 of the source container 2. The vacuum may suck liquid from the bulk storage 112 along the pipes 16 or 17, into pipe 18, and into the source container 2. The level of liquid in the source container 2 may rise, until the fill level sensor 40 of the source container 2 indicates to the controller 56 that the liquid has reached the fill level. In response to that indication, the controller may close the valve in the valve block 6c to shut off the compressed air to the vacuum generator 7 so that vacuum is no longer supplied to the source container 2 and no further liquid is drawn from the bulk storage 112, and the controller may also close the valve in valve block 6a to close the passageway either along pipes 16 and 18 or 17 and 18.

[0067] If the level of the liquid in the source container 2 continues to rise further for any reason, for example due to a malfunction of the fill lever sensor 40, then when the liquid level reaches the emergency level the emergency level sensor 41 of the source container 2 may indicate this to the controller 56 and the controller 56 may sound an alarm and / or issue a notification to the remote computer 122, signifying that a malfunction has occurred. The controller 56 may also close the valve in the valve block 6c to shut off the compressed air to the vacuum generator 7, and close the valve in valve block 6a to close the passageway either along pipes 16 and 18 or 17 and 18.

[0068] Similarly, when the source container 3 becomes depleted of liquid to the depletion level, the depletion level sensor 39 of the source container 3 may indicate to the controller 56 that the liquid has fallen to the depletion level. In response to that indication, the controller 56 may open a valve in valve block 6b to open a passageway either along pipes 21 and 23 or 22 and 23, and open a valve in valve block 6c to open a passageway from the air valve block 29 to the vacuum generator 8. Compressed air may enter the vacuum generator 8 and a vacuum may be applied along the pipe 25 and into the source container 3 via the vacuumport 44 of the source container 3. The vacuum may suck liquid from the bulk storage 113 along the pipes 21 or 22, into pipe 23, and into the source container 3. The level of liquid in the source container 3 may rise, until the fill level sensor 40 of the source container 3 indicates to the controller 56 that the liquid has reached the fill level. In response to that indication, the controller may close the valve in the valve block 6c to shut off the compressed air to the vacuum generator 8 so that vacuum is no longer supplied to the source container 3 and no further liquid is drawn from the bulk storage 113, and the controller may also close the valve in valve block 6a to close the passageway either along pipes 16 and 18 or 17 and 18.

[0069] If the level of the liquid in the source container 2 continues to rise further for any reason, for example due to a malfunction of the fill lever sensor 40, then when the liquid level reaches the emergency level the emergency level sensor 41 of the source container 3 may indicate this to the controller 56 and the controller 56 may sound an alarm and / or issue a notification to the remote computer 122, signifying that a malfunction has occurred. The controller 56 may also close the valve in the valve block 6c to shut off the compressed air to the vacuum generator 7, and close the valve in valve block 6a to close the passageway either along pipes 16 and 18 or 17 and 18.

[0070] The controller 56 may control the valve block 6c to only send the compressed air to one of the vacuum generators 7 and 8 at a time, so that each vacuum generator will always receive the same pressure of compressed air as the other vacuum generator(s), and the vacuum generators will all be consistent with one another in their operation. The pressure level of the compressed air may for example be about 3 bar (300 kPa), and the level of vacuum generated by each vacuum generator may for example be around 60 kPa below atmospheric pressure.

[0071] The schematic diagram of Fig. 6 shows an apparatus 200 comprising the liquid mixing station 100 and four bulk containers 140, 141, 145 and 146 that are connected to the liquid mixing station 100 by respective pipes 16a, 17a, 21a and 22a. The liquid mixing station 100 may be mounted on a wall of a building, and thebulk containers may be standing on the floor beneath the liquid mixing station, to provide the bulk storage 112 and 113.

[0072] Specifically, the bulk storage 112 may comprise a bulk container 140 and a further bulk container 141. A pipe 16a may be connected from the bulk container 140 to the connection 37 of the pipe 16. A pipe 17a may be connected from the bulk container 140 to the connection 37 of the pipe 17. The bulk storage 113 may comprise a first additional bulk container 145 and a second additional bulk container 146. A pipe 21a may be connected from the bulk first additional container 145 to the connection 37 of the pipe 21. A pipe 22a may be connected from the second additional bulk container 146 to the connection 37 of the pipe 22. Each of the pipes 16a, 17a, 21a and 22a may comprise an opening at the bottom of the corresponding bulk container.

[0073] Initially the bulk containers 140 and 141 may be both filled with a first liquid, for example concentrated disinfectant, and the bulk containers 145 and 146 may be both filled with a second liquid, for example concentrated emollient. The liquid mixing station may draw liquid from only one of the bulk containers in each bulk storage at a time, and when the liquid in that bulk container is exhausted, liquid can be drawn from the other bulk container instead whilst the exhausted bulk container is being replaced.

[0074] The following discussion considers the source container 2 and the bulk storage 112, but is equally applicable to the source container 3 and the bulk storage 113. The controller 56 may be configured to draw the liquid from the bulk container 140 into the source container 2, by controlling the valves in the valve blocks 6b and 6c as described further above to supply a vacuum into the source container 2 via the vacuum ports 44. Once the vacuum generator 7 is activated, the level of vacuum inside the source container 2 begins to rise, and liquid from the bulk container 140 will be sucked up through the pipe 16a, through the valve block 6a and into the inlet port 43 of the source container 2.

[0075] The lower the level of the liquid inside the bulk container 140, the higher the level of the vacuum inside the source container 2 may rise before the liquid willenter the source container 2 and begin to arrest the rise in vacuum. The level of vacuum inside the source container 2 is sensed by the vacuum sensor 45, and indicated to the controller 56 via the header connector 46. The controller 56 may therefore determine the level of the liquid inside the bulk container 140 based on the vacuum sensor 45.

[0076] The controller may be configured to measure the level of vacuum after a delay period of time from activating the vacuum generator so the measurement is taken whilst the liquid is flowing into the source container and the vacuum is at a stable level.

[0077] The controller 56 may monitor the rate of consumption of the liquid from the bulk container 140 based on the measurements taken by the vacuum sensor 45, or based on how frequently the liquid in the source container 2 is replenished, and use this to estimate how much longer the bulk container will last for before it is exhausted of liquid. The estimated time until exhaustion may be compared to a threshold period of time set by the famer via the computing device 122, and a notification of imminent exhaustion may be issued once the estimated time until exhaustion falls beneath the threshold period of time.

[0078] Once the liquid in the bulk container 140 becomes exhausted, if the bulk container 140 is open to the atmosphere then air will rush into the pipe 16a instead of liquid and the vacuum inside the source container 2 will drop dramatically, to beneath an empty threshold level. The vacuum sensor 45 indicates this drop to the controller 56, and in response to this indication the controller determines the bulk container 140 is exhausted. The empty threshold level may for example be 15 kPa below atmospheric pressure, and so if the vacuum drops to only 10 kPa below atmospheric pressure for example, then the controller determines the bulk container 140 is exhausted. Alternatively, if the bulk container 140 is not open to the atmosphere, for example if the bulk container is sealed around the pipe 16a and is made of a flexible material that collapses as the liquid is withdrawn from it, then when all the liquid has been sucked out of the bulk container 140 and no further liquid / gas can be drawn, the vacuum inside the source container 2 will rise dramatically. The vacuum sensor 45 indicates this rise to the controller 56, and inresponse to this indication the controller determines the bulk container 140 is exhausted.

[0079] Once the controller 56 determines that the bulk container 140 is exhausted, the controller 56 controls the valve block 6b to close the passageway from the pipe 16 to the pipe 18, and instead open the passageway from the pipe 17 to the pipe 18, so that liquid can be drawn from the further bulk container 141 via the pipe 17a instead of the bulk container 140, and the bulk container 140 can be replaced or replenished. The controller may issue a notification to inform the farmer that the bulk container 140 is ready to be replaced or replenished. The liquid may be drawn from the further bulk container 141 until the controller 56 determines the further bulk container 141 has been exhausted, whereupon the controller 56 may switch back to drawing the liquid from the replaced / replenished bulk container 140.

[0080] The controller 56 may be configured to draw the liquid for the source container 3 via the pipes 21a and 22a, by switching between the first additional bulk container 145 and the second additional bulk container 146 as they become exhausted, in the same manner as it switches between the bulk container 140 and further bulk container 141. The volume of each bulk container may be at least five times greater than the volume of each source container, so that each source container can be refilled multiple times from the bulk container before the bulk container requires replacement or replenishment.

[0081] The arrangement shown in Fig. 6 may be expanded to add further pipes running parallel to the pipes 16a, 17a, 21a and 22a, and that each have a further opening part-way down each bulk container, at a depletion level of the liquid inside the bulk container. For example, a further pipe may run parallel to the pipe 16a and be slightly shorter than the pipe 16a so that it has an opening in the bulk container 140 intermediate of the top and bottom of the bulk container, corresponding to a depletion level. The valve block 6a may be configured to open a further passageway from the further pipe to the inlet port 43 under control of the controller. The controller may determine the liquid has dropped to the depletion level once air rushes into the opening of the further pipe and causes the sensed vacuum to drop below a depletion level threshold. The depletion level thresholdmay for example be 15 kPa below atmospheric pressure. A notification that the bulk container 140 is at the depletion level, for example half empty, may then be issued to the farmer, for example by sending the notification to the remote computer 122 via the transceiver 57. The controller may then switch the valve block 6a to close the further passageway from the further pipe and to open the passageway from the pipe 16a, to allow the remaining liquid to be drawn from the bulk container 140.

[0082] The storage vessel 4 may store liquids that have been pumped from the source vessel 1 , source container 2 and source container 3 into the storage vessel 4 by the pump 5. As shown in Fig. 3, the storage vessel 4 may comprise an emergency level sensor 35, a depletion level sensor 34 and a fill level sensor 34a. The depletion level sensor 34, fill level sensor 34a and emergency level sensor 35 may be float sensors that sense when the liquid level in the storage container is above or below the sensor. Accordingly, the depletion level sensor 34 may be at a depletion level within the storage vessel 44, the fill level sensor 34a may be at a fill level within the storage vessel 44, above the depletion level sensor 34, and the emergency level sensor 35 may be at an emergency level within the storage vessel 44, beneath both the depletion and fill level sensors 34 and 34a.

[0083] The depletion level sensor 34, fill level sensor 34a and emergency level sensor 35 may all be connected to the controller 56 via a cable(s) (not shown in Figs). Thus, the controller 56 may monitor the level of the liquid in the storage vessel 4 using the depletion level sensor 39, fill level sensor 40 and emergency level sensor 41.

[0084] The storage vessel 4 may comprise an inlet 38 for liquids pumped from the source vessel 1 , source container 2 and / or source container 3. The inlet 38 may be positioned to eject the liquids into the storage vessel 4 near the bottom of the storage vessel 1 , for example beneath the depletion sensor 34 or the emergency level sensor 35, so the liquids will be ejected into the existing liquid already in the storage vessel and create turbulence within the existing liquid.The storage vessel 4 may comprise an outlet 36 for the liquid stored in the storage vessel. The outlet 36 may be at the bottom of the storage vessel, and may for example be connected to onward piping and control systems to control when the liquids are delivered for the end purpose, such as teat dipping. Once enough liquid has been outlet from the storage vessel for the level of liquid inside the storage vessel to fall to the depletion level, the depletion level sensor 34 indicates this to the controller 56. In response to that indication, the controller 56 may begin a mixing cycle to replenish the liquid stored in the storage vessel back up to the fill level, using liquid from the source vessel 1, the source container 2 and / or the source container 3.

[0085] The liquid mixing station may comprise a pipe 11 that is connected from the outlet 33 of the source vessel 1 to a valve block 6d of the valve arrangement 6, a pipe 9 that is connected from the outlet port 42 of the source container 2 to the valve block 6d, and a pipe 10 that is connected from the outlet port 42 of the source container 3 to the valve block 6d. The valve block 6d may also be connected to the pump 5 via a pipe 12, and the valve block 6d may be configured to open and close a first passageway leading from the pipe 9 to the pipe 12, a second passageway leading from the pipe 10 to the pipe 12, and a third passageway leading from the pipe 11 to the pipe 12. The valve block 6d may be connected to the controller 56, and the controller 56 may select which one of those passageways the valve block 6d opens at any given time. The controller 56 and / or valve block 6d may be configured to only allow one of those passageways to be open at a time.

[0086] The pipe 12 may be connected from the valve block 6d to an inlet of the pump 5. The pump 5 may have an outlet connected to a pipe 13, and the pipe 13 may lead from the outlet of the pump 5 to the inlet 38 of the storage vessel 4. The pump 5 may be controlled by the controller 56 to pump liquid from the valve block 6d into the storage vessel 4, when the controller 56 receives the indication from the depletion level sensor 34 that the level of liquid in the storage vessel 4 has fallen to or below the depletion level, or receives the indication from the emergency level sensor 35 that the level of liquid in the storage vessel 4 has fallen to or below the emergency level.For example, the pump 5 may be a diaphragm pump as shown in Fig. 7. The diaphragm pump may comprise a diaphragm 134 that moves within a pump chamber 130, and a piston 132 that moves within an air chamber 131. The diaphragm 134 may be connected to the piston by a pump shaft 133, so that the diaphragm and piston move in unison within the pump and air chambers, respectively.

[0087] The pump 5 may comprise a first air inlet 14a for connecting to the pipe 14, and a second air inlet 15a for connecting to the pipe 15. The first and second air inlets 14a and 15a may receive compressed air from the valve block 6c via the pipes 14 and 15, respectively. The pump 5 may also comprise a liquid inlet 12a for connecting to the pipe 12 and receiving liquid from one of the liquid sources via the valve block 6d, and may also comprise a liquid outlet 13a for connecting to the pipe 13 and sending liquid from the pump 5 to the storge vessel 4.

[0088] The liquid inlet 12a may comprise a check valve V12 that only allows flow of liquid into the pump 5, and the liquid outlet 13a may comprise a check valve V13 that only allows flow of liquid out of the pump 5. Fig. 7 shows the pump in a state where the diaphragm 134 is moving upwardly in the pump chamber 130 to pump liquid out of the liquid outlet 13a, and so the check valve V13 is open and the check valve V12 is closed. When the diaphragm 134 moves downwardly, the check valve V12 opens to suck liquid from the pipe 12 into the pump chamber 130, and the check valve V13 closes.

[0089] The diaphragm 134 may be driven to move by the piston that is connected to the diaphragm by the pump shaft 133. When compressed air is inlet into the air chamber 131 via only the first air inlet 14a, the piston and diaphragm and driven downwardly as viewed in Fig. 7, and when compressed air is inlet into the air chamber 131 via only the second air inlet 15a, the piston and diaphragm are driven upwardly as viewed in Fig. 7.

[0090] The controller 56 may be configured to control the valve block 6c to open and close passageways from the air valve 29 to the pipes 14 and 15, to drive thepiston 132 and therefore the diaphragm 134, to pump liquid from the liquid inlet 12a to the liquid outlet 13a. For example the controller may repeatedly switch the valve block 6c between applying compressed air to pipe 14 and applying compressed air to pipe 15, to move the diaphragm back and forth at a desired frequency, corresponding to the speed of the pump. Various other constructions of diaphragm pumps are known in the art and could alternatively be used.

[0091] Since the diaphragm of the pump 5 is driven by compressed air, the amount of time required for the diaphragm to move to its full extent under the pressure exerted by the compressed air will depend on the viscosity of the liquid being pump. The diaphragm must be moved to its full extent to accurately judge the amount of liquid that is pumped by each stroke of the diaphragm. Therefore, the liquid mixing station may comprise one or more temperature sensors connected to the controller 56, to make allowance for higher liquid viscosities when the temperature is low. Specifically, the lower the measured temperature, the lower the frequency that the controller 56 will switch the valve block 6c at, so that more time is provided for the diaphragm to reach its full extent under the pressure of the compressed air and the pump runs more slowly. Thus, the diaphragm pump may be a variable speed diaphragm pump. The temperature sensors may for example comprise a temperature sensor 135 (see Fig. 2) that measures the temperature of the liquid inside the source container 2, and reports the temperature to the controller 56 via the header connector 46.

[0092] The controller 56 may be configured to pump liquid into the storage vessel 4 using the pump 5, and may be configured to draw that liquid from the source vessel 1 , the source container 2 and the source container 3 in sequence.

[0093] For example, the controller 56 may control the valve block 6d to open the passageway from the source vessel 1 to the pump 5, thereby closing the passageways from the source containers 2 and 3 to the pump 5, and to control the valve block 6c to move the diaphragm of the pump 5 a first number of times, to pump a first quantity of liquid from the source vessel 1 into the storage vessel 1.The controller 56 may then control the valve block 6d to open the passageway from the source container 2 to the pump 5, thereby closing the passageways from the source vessel 1 and the source container 3 to the pump 5, and to control the valve block 6c to move the diaphragm of the pump a second number of times, to pump a second quantity of liquid from the source container 2 into the storage vessel 1.

[0094] The controller 56 may then control the valve block 6d to open the passageway from the source container 3 to the pump 5, thereby closing the passageways from the source vessel 1 and the source container 2 to the pump 5, and to control the valve block 6c to move the diaphragm of the pump a third number of times, to pump a third quantity of liquid from the source container 2 into the storage vessel 1 , completing the sequence.

[0095] The sequence may be repeated multiple times, such that each of the first, second and third quantities are relatively small compared to the size of the storage vessel. Repeating the sequence multiple times helps provide a well-mixed liquid in the source container. Once the level of the liquid in the source container reaches the fill level, the fill lever sensor 34a indicates this to the controller 56, and the controller 56 ceases to drive the pump diaphragm anymore using the valve block 6c, to cease pumping of liquid.

[0096] The ratio between the first, second and third quantities of liquid may be referred to as a mix ratio, and differing mix ratios provide the liquid in the storage vessel with differing characteristics. For example, to provide a weaker solution with good teat-conditioning properties the first quantity (corresponding to water from the source vessel 1) may be 20 units in volume, the second quantity (corresponding to disinfectant from the source container 2) may be 1 unit in volume, and the third quantity (corresponding to emollient from the source container 3) may be 2 units in volume, or to summarise, a mix ratio of 20:1:2. To provide a stronger solution with high disinfecting properties, the first quantity may be 15 units in volume, the second quantity may be 2 units in volume and the third quantity may be 1 unit in volume, or to summarise a mix ratio of 15:2:1.In use, as shown in Fig. 5 the controller 56 may be configured to retrieve the weather forecast data from the cloud-based server computer 120 using the transceiver 57, in a first step 125. The weather forecast data may be retrieved for the geographic location of the liquid mixing station, based on a geographic location stored in a memory of the controller or based on satellite / cellular signals received via the transceiver. Then, in a second step 126 the controller 56 may determine the mix ratio of the liquids based on the weather forecast, and in a third step 127 the controller may drive the pump 5 to pump quantities of liquids corresponding to the mix ratio into the storage vessel.

[0097] The controller typically comprises at least one memory and at least one processor. The memory may store a mapping scheme between the forecasted weather and the mix ratio, for example if the weather forecast data shows that the humidity is expected to fall beneath a certain level then the mapping scheme may dictate a certain increase in the proportion of emollient to be included in the mix, to provide additional protection against teat skin cracking. If the temperature is expected to drop below a certain level, then the mapping scheme may dictate a certain increase in the proportion of disinfectant in the mix since the teats may take longer to dry after milking and bacteria may have longer to grow on the skin. . If the windspeed is expected to increase above a certain level, then the mapping scheme may dictate a certain increase in the proportion of emollient in the mix to counteract the increased drying of the teats due to the wind.

[0098] A mapping scheme may be defined or adjusted by a farmer using the remote computer 122, and the remote computer 122 may send the mapping scheme to the controller 56 via a network and the transceiver 57, to provide the system with flexibility and allow some user customisation. Optionally, the remove computer 122 may be a smartphone running an app associated with the liquid mixing station, and which may allow the farmer to program how the liquid mixing station is to operate. The controller 56 may also send statistics on the usage and mix radios of the liquids to the server computer and / or the remote computer 122 via the transceiver 57, for monitoring purposes.The controller 56 may log the amount of time that passes between each mixing cycle, for example based on the average amount of time that it takes for the storage vessel to be depleted from the fill level down to the depletion level. Since the amount of teat dip consumed per day is normally the same from one day to the next, the time duration that the previously mixed liquid lasted for before the depletion sensor was triggered, will be similar to the time that the next batch of mixed liquid will last for. The amount of time the next batch of mixed liquid will last for may be used to define the period of weather forecast data that will be used to calculate the mix ratio.

[0099] The controller 56 may average the forecasted temperature, windspeed and humidity over the period, and calculate the mix ratio to provide the desired mix of liquids in the storage vessel. If the current mix of liquids in the storage vessel is very different to the desired mix of liquids, then the controller may adjust the mix ratio for the next mix cycle based on the volume of liquid in the storage vessel at the current mix ratio, typically the volume of liquid in the storage vessel when the liquid is at the depletion level.

[0100] The controller 56 may record the mix ratio of each mixing cycle, and adjust the mix ratio for the next mixing cycle based on the mix ratios used for the preceding mix cycles, for example so that a mix with high disinfecting properties is mixed at least once in every certain number of days.

[0101] Whilst the illustrated embodiment only uses a single pump 5, it will be appreciated that the single pump could be replaced with multiple pumps if desired, for example one pump for each one of the source vessel and source containers. The diaphragm pump(s) could be replaced with alternate type(s) of pump(s) if desired.

[0102] Whilst the illustrated embodiment has three liquid sources, corresponding to the source vessel 1 and the source containers 2 and 3, it will be appreciated that additional liquid sources for mixing further ingredients of the teat dip could be added to the embodiment if desired, or one of the liquid sources could be removedfrom the embodiment leaving only two liquid sources for mixing, such as concentrated teat dip and water.

[0103] The liquids from the liquid sources of the illustrated embodiment are mixed together in the storage vessel as the different liquids are successively pumped into the storage vessel in sequence. However, the liquids could alternatively be pumped along a common manifold at the same time as one another to effect the mixing before the storage vessel, or the storage vessel could comprise a rotatable paddle driven under control of the controller to mix the liquids together.

[0104] Many other variations of the described embodiments falling within the scope of the invention will be apparent to those skilled in the art.

Claims

CLAIMS1. A liquid mixing station, comprising a controller, a vacuum generator and at least two liquid sources for supplying respective liquids that are to be mixed with one another, wherein at least one of the liquid sources is a source container for storing a respective liquid to be mixed, wherein the source container comprises a vacuum port for supplying a vacuum from the vacuum generator into the source container, a liquid inlet for sucking liquid from a bulk container, and a vacuum sensor for sensing a level of vacuum inside of the source container, wherein the vacuum sensor is connected to the controller and wherein the controller is configured to determine a level of liquid remaining in the bulk container based on a level of vacuum sensed by the vacuum sensor.

2. The liquid mixing station of claim 1 , comprising a valve arrangement connected between the liquid inlet and the bulk container, the valve arrangement configured to open and close a passageway leading from the bulk container to the liquid inlet.

3. The liquid mixing station of claim 2, wherein the valve arrangement is further configured to open and close a passageway leading from a further bulk container to the liquid inlet.

4. The liquid mixing station of claim 3, wherein the controller is configured to control the valve arrangement to open the passageway from the bulk container to the liquid inlet or open the passageway from the further bulk container to the liquid inlet in dependence on the level of vacuum sensed by the vacuum sensor.

5. The liquid mixing station of any preceding claim, wherein the controller is configured to determine the bulk container has been emptied of liquid based on the level of vacuum sensed by the vacuum sensor.

6. The liquid mixing station of claim 5, wherein the controller is configured to determine the bulk container has been emptied of liquid when the level of vacuum sensed by the vacuum sensor falls below an empty threshold level.

7. The liquid mixing station of claim 5, wherein the controller is configured to determine the bulk container has been emptied of liquid when the level of vacuum sensed by the vacuum sensor rises above an empty threshold level.

8. The liquid mixing station of any one of claims 5 to 7, when appended to claim 4, wherein the controller is configured to control the valve arrangement to open the passageway from the further bulk container to the liquid inlet in response to determining the bulk container has been emptied of liquid.

9. The liquid mixing station of any preceding claim, wherein the controller is configured to issue a notification that the level of liquid remaining in the bulk container has fallen beneath a depletion level based on the level of vacuum sensed by the vacuum sensor.

10. The liquid mixing station of claim 9 when appended to claim 2 or any claim dependent thereon, wherein the valve arrangement is configured to open and close a further passageway leading from the bulk container to the liquid inlet, and wherein the controller is configured to compare the level of vacuum sensed by the vacuum sensor to a depletion threshold level whilst the further passageway is open.

11. The liquid mixing station of any preceding claim, wherein the source container comprises a depletion level sensor configured to sense when the level of liquid in the source container has fallen to a depletion level, wherein the depletion level sensor is connected to the controller and wherein the controller is configured to activate supply of a vacuum from the vacuum generator into the source container in response to a depletion signal from the depletion level sensor indicating that the level of liquid in the source container has fallen to the depletion level.

12. The liquid mixing station of any preceding claim, wherein the source container comprises a fill level sensor configured to sense when the level of liquid in the source container has risen to a fill level, wherein the fill level sensor isconnected to the controller and wherein the controller is configured to deactivate supply of a vacuum from the vacuum generator into the source container in response to a fill signal from the fill level sensor indicating that the level of liquid in the source container has risen to the fill level.

13. The liquid mixing station of claim 12, wherein the source container comprises an emergency level sensor configured to sense when the level of liquid in the source container has risen above the fill level to an emergency level, wherein the emergency level sensor is connected to the controller and wherein the controller is configured to signal an alarm in response to an emergency signal from the emergency level sensor indicating that the level of the liquid in the source container has risen to the emergency level.

14. The liquid mixing station of any preceding claim, comprising a compressed air source, wherein the compressed air source is connected to the vacuum generator and the vacuum generator comprises a passageway for carrying the compressed air and a venturi hole into the passageway for generating the vacuum.

15. The liquid mixing station of claim 14 when appended to claim 11 or appended to any claim dependent on claim 11 , comprising an air valve arrangement configured to open and close a passageway from the compressed air source to the vacuum generator, and wherein the controller is configured to activate the supply of the vacuum from the vacuum generator into the source container by controlling the air valve arrangement to open the passageway.

16. The liquid mixing station of claim 14 when appended to any one of claims 12 and 13, comprising an air valve arrangement configured to open and close a passageway from the compressed air source to the vacuum generator, and wherein the controller is configured to deactivate the supply of the vacuum from the vacuum generator into the source container by controlling the air valve arrangement to close the passageway.

17. The liquid mixing station of any preceding claim, comprising a mixing vessel and at least one pump for pumping the respective liquids from the liquid sources into the mixing vessel, the mixing vessel allowing mixing and storage of the respective liquids for later use.

18. The liquid mixing station of any preceding claim, wherein the source container is a first source container, the first source container being a first one of the at least two liquid sources, wherein the liquid mixing apparatus comprises a second source container being a second one of the at least two liquid sources, and wherein the second source container comprises a vacuum port for supplying a vacuum into the second source container, a liquid inlet for receiving a liquid from an additional bulk container in which the liquid is held, and a vacuum sensor for sensing a level of vacuum inside of the second source container, wherein the vacuum sensor is connected to the controller and wherein the controller is configured to determine a level of liquid remaining in the additional bulk container based on a level of vacuum sensed by the vacuum sensor of the second source container.

19. The liquid mixing station of claim 18, wherein the first source container and the second source container are arranged at a same height as one another within a housing of the liquid mixing station.

20. The liquid mixing station of claim 18 or 19, wherein the vacuum generator is a first vacuum generator and the liquid mixing station comprises a second vacuum generator configured to supply a vacuum to the vacuum port of the second source container.

21. The liquid mixing station of claim 20 when claim 18 is appended to claims 15 or 16, wherein the air valve arrangement is controlled by the controller to supply the compressed air to only one of the first vacuum generator and the second vacuum generator at a time.

22. The liquid mixing station of claim 14 or any claim dependent thereon, wherein the compressed air source is an inlet for compressed air, and wherein theinlet is connected to an air filter for filtering the compressed air prior to the compressed air entering the vacuum generator.

23. The liquid mixing station of any preceding claim, wherein the liquid mixing station is a teat dip station.

24. An apparatus comprising the liquid mixing station of any preceding claim, a bulk container and a pipe leading from the bulk container into the liquid mixing station for conveying liquid from the bulk container to the liquid mixing station, wherein the bulk container is positioned at a lower height than the source container of the liquid mixing station.

25. The apparatus of claim 24, wherein a volume of the bulk container is at least five times greater than a volume of the source container.

Images