Autonomous manure removal vehicle, valve assembly for such a vehicle and method of operating such a vehicle

Abstract

Autonomous manure removal vehicle adapted for removing manure from a floor of an animal space, comprising: - at least two wheels, at least one electric motor device for driving at least one of the at least to wheels, and a control device for controlling the manure removal vehicle in at least a cleaning mode and a dumping mode, - a manure storage tank comprising a bottom provided with at least one opening for supply of manure to and / or discharge of manure from the tank and an upper part provided with an air exchange opening for the exchange of air between the interior of the tank and ambient air, and - a manure loading system adapted for moving manure from the floor into the tank when the vehicle is controlled to operate in the cleaning mode, characterised in that, the vehicle further is adapted to, when the vehicle is controlled to operate in the dumping mode, generate a forced airflow into the tank via the air exchange opening, causing an over-pressure inside the tank.

Description

AUTONOMOUS MANURE REMOVAL VEHICLE, VALVE ASSEMBLY FOR SUCH AVEHICLE AND METHOD OF OPERATING SUCH A VEHICLEFIELDThe invention relates to an autonomous manure removal vehicle adapted for removing manure from a floor of an animal space, comprising at least two wheels, at least one electric motor device for driving at least one of the at least two wheels, and a control device for controlling the manure removal vehicle in at least a cleaning mode and a dumping mode, a manure storage tank comprising a bottom provided with at least one opening for supply of manure to and / or discharge of manure from the tank and an upper part provided with an air exchange opening for the exchange of air between the interior of the tank and ambient air, and a manure loading system adapted for moving manure from the floor into the tank when the vehicle is controlled to operate in the cleaning mode. The invention also relates to a valve assembly for an autonomous manure-removal vehicle. Further, the invention relates to a method of operating an autonomous manureremoval vehicle.BACKGROUND

[0001] Autonomous agricultural manure-removal vehicles are known in the state of the art, such as for example W02013010785A1. Such vehicles are suitable for sucking slurry or manure whereby an opening in the bottom of the tank is used as inlet opening. Emptying of the tank is performed with the vehicle being located over a dump opening, using a manure discharge opening in the bottom. The discharge of manure is performed under gravity.

[0002] Although this is a simple and cost effective design, a downside is that the tank may take some time to empty, and the tank may not fully empty each time. Particularly when the collected manure is on the thicker and / or dryer side, a part of this collected manure tends to “stick” together inside the tank, resulting in manure slowly and / or not fully exiting the tank. Ultimately this can result in a smaller tank capacity during the next cleaning session.

[0003] It is an objective of the invention to better empty the manure tank after each cleaning session.SUMMARY OF THE INVENTION

[0004] According to a first aspect of the invention a solution to this objective is provided in an autonomous manure removal vehicle according to claim 1. The autonomous manure removal vehicle is adapted for removing manure from a floor of an animal space and comprises at least two wheels, at least one electric motor device for driving at least one of the at least two wheels, and a control device for controlling the manure removal vehicle in at least a cleaning mode and a dumping mode. The vehicle further comprises a manure storage tank comprising a bottom provided with at least one opening for supply of manure to and / or discharge of manure from the tank and an upper part provided with an air exchange opening for the exchange of air between the interior of the tank and ambient air, and a manure loading system adapted for moving manure from the floor into the tank when the vehicle is controlled to operate in the cleaning mode. The vehicle is adapted to generate a forced airflow into the tank via the air exchange opening when the vehicle is controlled to operate in the dumping mode. The forced airflow causes over-pressure inside the tank, which forces the manure stored therein out from the at least one opening in the bottom thereof. Thus in dumping mode the manure loading system is no longer moving manure from the floor into the tank, but instead the tank is emptied with the aid of over-pressure. Forcing out the manure results in the manure leaving the interior of the tank faster. Moreover, the over-pressure in the tank causes the manure to be compacted towards the opening for discharge, thereby reducing the amount of manure sticking to the tank and thus resulting in a more complete emptying of the tank.

[0005] Preferably at least the opening for discharge of manure from the tank is situated at least partly, and preferably completely, at the lowest level of the bottom, allowing gravity to work together with the pressure that is generated above the manure surface formed by the manure inside the tank, to empty the tank substantially completely.

[0006] Preferably the at least one opening for the supply of manure to and / or discharge of manure from the tank is a single opening, resulting in a simple and robust design that can be manufactured with the least amount of manufacturing steps.

[0007] The upper part may be considered all parts of the tank above the bottom, thus effectively the air exchange opening may be provided in any side wall or top of the tank. However, to prevent manure from covering the opening, either the air exchange opening itself is to be provided at a height of the tank that corresponds to a maximum fill level of the tank, or the air exchange opening is to be connected to air exchange tubing that extends inside the tank and has an inlet / outlet opening that is positioned at a heightcorresponding to this maximum fill level. A height corresponding to a maximum fill level may be a height of a maximum fill level plus an additional margin, to prevent manure from entering the inlet / outlet opening of the air exchange opening due to manure sloshing inside the tank caused by vehicle movements. The maximum fill level may be monitored by the vehicle through any suitable manner using any suitable tank level sensor, i.e. through sensing a weight, through sensing a volume or level present inside the tank, or through sensing a change in force required to move manure into and / or with the vehicle.

[0008] The manure removal vehicle may be configured to operate in accordance with a cleaning plan, which comprises routes, specific location points and / or area’s for the vehicle to operate in and times, time blocks or intervals during which the vehicle is to operate there. This plan may be fully or partially pre-programmed and / or adjusted based on some learning algorithm that accounts for specific conditions in the animal space.

[0009] Various manure loading systems are foreseen to be used with the invention. For example, the manure loading system may be adapted to scrape, scoop and / or convey manure from the floor into the tank.

[0010] Additionally or alternatively, the manure loading system may comprise a pump device comprising an air pump and a valve assembly comprising at least one valve. Herein, the air pump is with an air pump inlet in fluid connection with an interior of the tank via the air exchange opening and with an air pump outlet in fluid connection with an outlet of the vehicle to ambient air. The pump device is adapted to be switchable between at least a cleaning mode and a dumping mode under the control of the control device. When in the cleaning mode, the pump device has an airflow path from the air exchange opening via the air pump to the outlet for generating an under-pressure with respect to atmospheric pressure inside the tank to suck manure into the tank. The valve assembly is adapted and controlled to block an airflow path from the outlet to the air exchange opening which bypasses the air pump, when in the cleaning mode and preferably also when in the dumping mode.

[0011] Sucking manure into the tank through generating under-pressure in the tank enables the vehicle to take in manure with a minimum of moving parts, in particular with a minimum of moving parts in contact with the manure. As a result, the design can be considered robust and relatively economical. The valve assembly blocking an airflow path to the air exchange opening bypassing the air pump in cleaning mode ensures efficient operation of the air pump by preventing any air from entering into the tank from above the manure inlet opening, i.e. the at least one opening in the bottom of the tank is the only opening in direct contact with the ambient, such that when manure is present in front ofthe at least one opening this manure is sucked into the tank. When in the dumping mode, a direct airflow path from the outlet to the air exchange opening is preferably also blocked, at least when the forced airflow is intended to flow into the tank.

[0012] In an embodiment, the vehicle comprises a pump or compressor for generating the forced airflow. This pump or compressor is with a compressor outlet in fluid communication with the air exchange opening at least when the vehicle is controlled in the dumping mode and which is with a compressor inlet in fluid communication with the ambient air.

[0013] Such a pump or compressor can easily be added to an already existing design of a manure vehicle, regardless if the particular manure loading system already comprises an air pump or not. The pump or compressor may be arranged to be in direct fluid connection with the interior of the tank, i.e. a flowline may be provided between the compressor outlet and the tank.

[0014] Alternatively, if the vehicle comprises a pump device, the compressor outlet may be connected to the pump device, i.e. the pump or compressor may be connected to a vacuum pump circuit that is formed by the air pump and the valve assembly. This results in fewer openings being made in the tank, thereby lowering the risk of unwanted air-leaks. To prevent any air leaking past the air pump when the pump is in dumping mode, preferably the pump device is adapted to block the airflow path from the air exchange opening via the air pump to the outlet. This may be achieved through the air pump comprising a valve that closes off an airflow path through the air pump when the air pump is switched off. Additionally or alternatively, the valve assembly may be adapted to close off the airflow path from the air exchange opening via the air pump to the outlet.

[0015] In an embodiment, when the vehicle is controlled in the dumping mode, the valve assembly is adapted to have a forced airflow path from the outlet via the air pump inlet, through the air pump, via the air pump outlet to the air exchange opening, and the air pump is switched on to generate the forced airflow. This is the only path along which air flows into the tank, above the manure surface formed by the manure held therein.

[0016] Hereto, the valve assembly may be configured such that the air pump inlet is in fluid connection with the air exchange opening via a first closeable valve opening and in fluid connection with the outlet via a second closeable valve opening, and the air pump outlet is in fluid connection with the outlet via a third closeable valve opening and in fluid connection with the air exchange opening via a fourth closeable valve opening.

[0017] The valve openings may be independently closeable valve openings that are controlled to move in a required open or closed state according to the mode in which the vehicle is being controlled by the controller.

[0018] According to an embodiment, the pump device is adapted such that the first valve opening being open is mutually exclusive to the second valve opening being open and / or the third valve opening being open is mutually exclusive to the fourth valve opening being open. This adaptation reduces the risk of controller error.

[0019] According to a further embodiment, the first closeable valve opening and second closeable valve opening are comprised in a single two-way valve and / or the third closeable valve opening and fourth closeable valve opening are comprised in a single two-way valve. The use of two-way valves offer a reliable, non-electronic solution to ensure valve openings being open are mutually exclusive. Moreover, the use results in a space-saving design as less piping / channels are required to interconnect the valves. The piping / channels can be comprised in a housing enclosing at least one of the valves, preferably all valves, or connected to the housing and external thereto.

[0020] Alternatively, and to further limit the amount of parts in the design, according to an embodiment all of the first valve opening, second valve opening, third valve opening and fourth valve opening are comprised in a single four-way valve. This is the most compact design option.

[0021] In an embodiment, the control device is further adapted to control the vehicle in a hold mode wherein the pump device is arranged to block airflow to and from the air exchange opening and preferably wherein the air pump is switched off. Through blocking airflow to and from the air exchange opening, the air pressure inside the tank is kept at a substantially constant under-pressure with respect to atmospheric pressure which thereby holds the manure inside the tank. As a result, the at least one opening in the bottom of the tank does not need to be closed off with a valve, flap or other physical means of closure. Advantageously, this allows the air pump being switched off, thereby reducing energy consumption of the vehicle. The air pump itself may comprise a valve that blocks airflow through the air pump if the air pump is switched off. The valve assembly may then be adapted to only block other flow paths between the air outlet and air exchange opening, although the valve assembly may also be adapted to simultaneously block a flow path via the air pump, as an alternative or in addition to the air pump comprising a valve.

[0022] As indicated, various manure loading systems are foreseen to be used with the invention. Nonetheless, according to an embodiment, the vehicle comprises a floor-scraping part which, viewed in the normal forward direction of travel, narrows to a closed end, and wherein the at least one opening for supply of manure to the tank, viewed in the normal forward direction of travel, is situated in front of the floor-scraping part and is at least partly surrounded by the floor-scraping part. Thus no conveying or scooping system for moving manure into the tank is required in this particular design. This particular manure loading system has the advantage of comprising a minimum of moveable parts which may suffer from reduced operability over time due to becoming soiled or otherwise affected by manure.

[0023] According to a second aspect of the invention, a valve assembly is provided as recited in claim 12. The valve assembly is for an autonomous manure removal vehicle comprising a control device adapted to control the manure removal vehicle, a tank for storing manure and being provided with an air exchange opening, at least one opening for supply of manure to and / or discharge of manure from the tank, and an air pump. The valve assembly comprises a housing enclosing at least one valve and a motor which is connectable to the control device for receiving control input and adapted for operating the at least one valve based on received control input. The housing comprises an air exchange opening connection opening, an air pump inlet connection opening, an air pump outlet connection opening and an outlet connection opening and the at least one valve is adapted to be moveable between a first mode and a second mode. The first mode defines a flow path through the housing between the air exchange opening connection opening and the air pump inlet connection opening and between the air pump outlet connection opening and the outlet connection opening. The second mode defines a flow path through the housing between the outlet connection opening and the air pump inlet connection opening and between the air pump outlet connection opening and the air exchange opening connection opening. Advantageous, the valve assembly can be retrofitted to autonomous manure removal vehicles already having an air pump for sucking up manure into the tank. Thus allowing such vehicles already in operation being upgraded to have pressurized dumping, utilizing the air pump that is already present in the vehicle, i.e. with minimal additional components included. Moreover, the housing enclosing at least one valve and a motor for operating the valve being provided as a unit makes the valve assembly easy to handle and install, both during first installation either in a factory or on-site for retrofitting, and in case of maintenance and repair.

[0024] Preferably, the movability of the at least one valve is adapted to be controlled by the control device of the vehicle. Thus preferably the motor enclosed in the housing is adapted to respond to control signals from the control device of the vehicle, either directly,or via a master-slave interaction with a dedicated controller, such as a PLC, also comprised in the valve assembly.

[0025] In an embodiment, the at least one valve comprises a first two-way valve, arranged between the air pump inlet connection opening, the air exchange opening connection opening and the outlet connection opening, and / or a second two-way valve, arranged between the air pump outlet connection opening, the air exchange opening connection opening and the outlet connection opening. This makes for a more compact valve assembly. Preferably, the at least one valve preferably consists of the first two-way valve and the second two-way valve.

[0026] In an alternative embodiment, the at least one valve is a single 4-way valve, preferably a ball-valve comprising two through-channels, adapted to be moveable at least between the first mode and the second mode. This alternative embodiment provides the most compact valve assembly design.

[0027] According to a third aspect of the invention, a method of operating an autonomous manure removal vehicle adapted for removing manure from a floor of an animal space is provided. The vehicle comprises a control device for controlling the manure removal vehicle in at least a cleaning mode and a dumping mode, a manure storage tank comprising a bottom provided with at least one opening for supply of manure to and / or discharge of manure from the tank and an upper part provided with an air exchange opening for the exchange of air between the interior of the tank and ambient air, and a manure loading system adapted for moving manure from the floor into the tank when the vehicle is controlled to operate in the cleaning mode. The method comprises the steps of:- collecting manure in the tank by driving the vehicle through the animal space while operated in the cleaning mode at most until a maximum fill level of the tank is reached;- driving the manure removal vehicle to a dump opening provided at floor level and adapted for receiving manure from the manure removal vehicle;- releasing manure from the tank via the at least one opening for discharge of manure into the dump opening.The step of releasing manure from the tank comprises the vehicle being controlled to operate in dumping mode, thereby generating a forced airflow into the tank via the air exchange opening to raise the pressure inside the tank to a pressure that exceeds atmospheric pressure.

[0028] The forced airflow causes over-pressure inside the tank above the manure surface of the manure held therein, which forces the manure out from the at least one opening in the bottom thereof. Thus in dumping mode the manure loading system is no longer moving manure from the floor into the tank, but instead the tank is emptied with the aid of over-pressure. Forcing out the manure results in the manure leaving the interior of the tank more reliably. The over-pressure in the tank causes the manure to be compacted towards the opening for discharge, thereby reducing the amount of manure sticking together inside the tank and thus resulting in a more complete emptying of the tank. The method may be used to operate an autonomous manure removal vehicle according to the first aspect of the invention.

[0029] In an embodiment, the generating a forced airflow into the tank via the air exchange opening comprises switching on a pump or compressor that is in fluid connection with the air exchange opening via an outlet thereof. Thus a pump is used to generate the forced airflow into the tank.

[0030] In an embodiment, the collecting manure in the tank comprises having an air pump switched on and in fluid connection with the air exchange opening and ambient air so as to generate an airflow from the interior of the tank to the ambient air via the pump, thereby causing under-pressure with respect to atmospheric pressure inside the tank. Thus an air pump is used to move air from inside the tank out. This creates suction at the at least one opening provided in the bottom of the tank, causing manure to be sucked in when present in front of the at least one opening.

[0031] The air pump being a pump may also be used for generating the forced airflow into the tank, thereby limiting the amount of relatively expensive and large components needed to perform all steps of the method. In this particular embodiment, the generating of the forced airflow is performed with the air pump and the step of releasing manure from the tank comprises the redirecting of the airflow generated by the air pump to flow from the ambient air into the tank.

[0032] In an embodiment, the step of driving the manure removal vehicle to a dump opening comprises controlling the vehicle to operate in a holding mode, wherein the manure loading system is switched off and a substantially constant air pressure is maintained inside the tank. Maintaining the air pressure inside the tank at a substantially constant under-pressure with respect to atmospheric pressure allows the manure being held inside the tank without requiring the at least one opening in the bottom of the tank being closed off with a valve, flap or other physical means of closureDRAWINGS

[0033] The invention will be explained below with reference to the drawings, which show non-limiting exemplary embodiments of the invention, in which identical reference numerals indicate identical or similar components, and in which:

[0034] Figure 1 shows a perspective view of a manure removal vehicle according to an embodiment of the invention.

[0035] Figure 2 shows a schematic cross-section of a manure removal vehicle according to an embodiment of the invention;

[0036] Figure 3 schematically shows a pump device according to an embodiment of the invention or a part thereof,

[0037] Figures 4A, 4B and 4G respectively schematically show a pump device according to an embodiment of the invention, an airflow direction through this pump device when in cleaning mode and an airflow direction through this pump device when in dumping mode,

[0038] Figures 5A, 5B and 5C respectively schematically show a pump device according to another embodiment of the invention, an airflow direction through this pump device when in cleaning mode and an airflow direction through this pump device when in dumping mode,

[0039] Figures 6A, 6B and 6C respectively schematically show a further pump device according to an embodiment of the invention, an airflow direction through this pump device when in cleaning mode and an airflow direction through this pump device when in dumping mode.DETAILED DESCRI PTION

[0040] Figure 1 shows a perspective view of a manure removal vehicle 1 according to an embodiment of the invention. The manure removal vehicle 1 has a housing 2, with two sidewalls 26 and a hingeable cover 25. In each side wall 26, a wheel arch 27 is formed, accommodating a wheel 21. In front of the wheels, a manure introduction device 23 for introducing manure from the floor and moving the introduced manure to the interior of the manure tank 3 is provided. The manure introduction device forms a part of the manure loading system, and in the embodiment of the vehicle as shown has a manure scraping device for scraping and moving manure off a floor. When in use, the manure removal vehicle 1 is situated on the floor between the animals where manure and otherexcretory products of the animals are situated. In this exemplary embodiment, the manure removal vehicle 1 is supported on the floor by means of two wheels 21 and the manure scraping device 23. However, the manure removal vehicle 1 may also be supported differently, for example by means of a front wheel or a support element, such as a slide block.

[0041] The manure removal vehicle 1 is autonomous, thus the vehicle is unmanned and self-propelled. The manure removal vehicle 1 is able to autonomously find its way by means of an electronic control system with sensors, such as an ultrasound sensor and a gyroscope (not shown). On the basis of the signals detected by the sensors, the control system controls a drive system with electrical drive motors for the wheels 21 of the manure removal vehicle 1. The wheels are operable independently from one another, enabling the manure removal vehicle 1 to be steered and travel along a desired route. The desired route may be programmed as part of a cleaning plan of the manure removal vehicle 1 and / or the vehicle may be adapted to determine the desired route based on predetermined parameters set in a cleaning plan. The drive system and the control system are fed by a battery system 20 on board of the manure removal vehicle 1 . The battery system 20 comprises a rechargeable battery.

[0042] Figure 2 shows a schematic cross-section of a manure removal vehicle 1 according to an embodiment the invention, which may be the same manure removal vehicle as shown in Fig. 1 , or a different vehicle. The schematic cross-section shows the housing 2 of the manure removal vehicle 1 having a tank 3, a control chamber 11 and an outlet chamber 12, which tank and chambers are substantially closed off from one another. The tank 3 contains an air exchange 4, embodied here as a pipe extending from an air exchange opening 6 in a wall-section in an upper part of the tank 3 to an air intake / outlet opening 5 positioned in an upper part of the tank 3, and a tank level sensor 19. The control chamber 11 accommodates electric and electronic components which cannot withstand being in prolonged contact with manure and / or urine. These components include, as depicted, a rechargeable battery 20 of the vehicle 1 , a control device 10 and a pump device 7 with an intake pipe 8 and an outlet pipe 9. The control chamber 11 is provided with an access opening, for example for maintenance purposes, which is closable by the hingeable cover 25. The outlet pipe 9 of the pump device 7 extends into the outlet chamber 12, which in the depicted example is positioned below the control chamber 11 . The intake pipe 8 of the pump device 7 is connected to the air exchange opening 6.

[0043] The tank 3 is positioned behind the control chamber 11 and delimits a volume or manure storage chamber in which manure can be temporarily collected. The tank 3 comprises a bottom, which is provided with an opening 15 for supplying manure to and discharging manure from the tank 3. The pump device is adapted to generate an airflow B from the inside of the tank 3 to the outlet pipe 9, thereby causing suction at the opening 15. When the opening 15 is closed off by manure, the airflow results in an under-pressure inside the tank with respect to atmospheric pressure, causing the manure being sucked into the tank. As a result, the pump device 7 may be considered part of the manure introduction system in the embodiment of the manure removal vehicle 1 shown in Fig. 2. It will occur to the skilled person that the opening for supplying manure into and discharging manure from the tank may be provided as separate openings, although a single opening may be considered to be the simplest and most robust solution. Preferably, although not depicted, the bottom slopes obliquely towards the opening 15 intended for discharging manure, which is provided on a lowest level of the bottom.

[0044] The air exchange 4 is adapted to have an air exchange with the ambient occur in the tank 3 at a predetermined position that is relatively close to, or positioned in, a highest position inside the tank 3, to allow the tank 3 being filled to the maximum level. To prevent the tank being filled up with an amount of manure that exceeds the maximum level, i.e. to prevent that too much manure is sucked in and ends up in the pump device 7 via the air exchange opening 6, level sensor 19 is provided such that the reaching of the maximum level in the tank can be monitored. The control device 10 may be adapted to control the pump device 7 to stop generating additional under-pressure in the tank when a predetermined excessive level, such as the maximum level, is reached. Alternatives to the use of a level sensor 19 may be implemented with similar outcome, i.e. any measurement directly or indirectly relatable to a fill-level of the tank 3 could be used for generating a signal for the control device 10 upon which the pump device 7 may be stopped from generating under-pressure in the tank 3.

[0045] The manure scraper device 23 is situated at least partially below the housing 2 of the vehicle 1 , and extends under both the tank 3 and the outlet chamber 12. The manure introduction defines a manure sucking storage chamber 14, which is delimited at least on the rear side by the manure scraper 13 and connected to the tank 3 via the manure inlet opening 15. At the front side, the chamber is shown to be delimited by an optional sealing plate 16 with an opening 17. An optional front slide 18 is situated right at the front, adapted to prevent foreign bodies, such as stones and the like, from ending upunderneath the vehicle without impacting the manure supply to the manure sucking storage chamber 14.

[0046] The pump device is adapted to generate an airflow along outward airflow path B from the inside of the tank 3 to the outlet pipe 9. The pump device 7 forms part of the manure introduction system in the embodiment of the manure removal vehicle 1 shown in Fig. 2. When the vehicle 1 is operated to take in manure in the tank 3, the pump device 7 is operated to pump air, causing the outward airflow, i.,e. air is moved from the air intake / outlet opening 5 of the air exchange 4 via the air exchange opening 6 and the intake pipe 8 to the outlet pipe 9 of the pump device 7. The effectiveness and efficiency of this operation is aided by ensuring the manure inlet opening 15 of the tank 3 being substantially constantly covered by manure, which for example is achieved through the particular design of the manure introduction device as depicted.

[0047] Viewed in the direction of travel, which is indicated by an arrow A, the manure inlet opening 15 is situated at the end of the manure sucking storage chamber 14 where manure is collected in front of the manure scraper 13. In principle, a supply of manure is always present in the manure sucking storage chamber 14 during use, thereby substantially constantly covering the manure inlet opening 15 with manure. The covering of the manure inlet opening 15 enables the pump device 7 to effectively reduce the volume of air inside the tank 3 and thereby taking in manure without sucking in additional outside air. The moving of manure from the manure sucking storage chamber 14 into the tank 3 automatically causes an additional amount of manure being sucked up from the manure buffer forming in front of the sealing 16. Should this buffer be insufficient to fully fill the manure sucking storage chamber 14, an amount of air may nevertheless be sucked in. This, however, will merely cause the manure present in the tank 3 to slightly settle / flow out again via the manure inlet opening 15 until the manure inlet opening 15 is fully covered again.

[0048] The particular design of this manure loading system allows the system to work virtually like a non-return valve without using a physical valve. Nonetheless, it will be obvious to the skilled person that, although the absence of valves is a very significant advantage as manure has the disruptive tendency to cause severe encrustations, one or more valves may be included in the manure introduction device to achieve satisfactory manure uptake nonetheless. Moreover, it will be obvious to the skilled person that alternative configurations of the manure loading system may be implemented, such as for example using an alternatively configured manure introduction device comprising additional or alternative components, such as a loading belt and scooping system,thereby no longer requiring the generating of an airflow out from the tank 3 via the outlet 9 to load manure into the tank 3.

[0049] At a predetermined moment within the cleaning plan, such as when the tank 3 is full, the manure removal vehicle 1 travels to a dump in order to empty the tank 3 via the manure discharge opening 15. Preferably, the manure loading device is adapted to hold the air-pressure inside the tank 3 at a substantially constant reduced pressure (with respect to ambient pressure) when the tank 3 is full and the vehicle is traveling to a dump, thereby holding the manure inside the tank without requiring a physical valve closing off the manure inlet and manure discharge opening(s) 15. Although this may be achieved by keeping an air pump of the pump device 7 running to maintain constant pressure inside the tank, in view of energy consumption it is preferred to switch off the air pump and close off any flow paths between the air exchange opening 6 and the ambient air.

[0050] When the manure discharge opening 15 of the manure removal vehicle 1 is situated over the dump opening, the pump device 7 is adapted to increase the air pressure inside the tank 3 to a pressure that is higher than the ambient air pressure, as a result of which the manure is forced out of the tank via the discharge opening 15 together with the force of gravity. Hereto, a forced airflow is generated into the tank 3 via an opening in the upper part of the tank 3 that provides a substantially constant downward pressure over the fluid-surface of the manure inside the tank, forcing the manure out. A relatively low pressure of 0.1- 0.2 bar is found to be sufficient. Optionally, one or more flow paths between an upper end of the tank (above the fluid-surface of the manure) and ambient air may be released first, with the forced airflow being generated after a predetermined amount of time, for example 5 minutes, and / or based on a tank level sensor signal indicating that manure is not moving. This allows manure that is sufficiently thin to move quickly under gravity to exit the tank, while thicker manure is pushed out through the forced airflow. To ensure the forced airflow into the tank is optimally generating the constant downward pressure, any flow paths between tank and ambient not used for the forced airflow into the tank, other than the discharge opening 15, are substantially closed when the forced airflow is being generated.

[0051] This forced airflow could be provided by a pump or compressor 41 , via an independent flow channel 40 that interconnects an outlet of the pump or compressor 41a with the inlet 8 to the tank 3, as depicted in Figure 3. The depicted pump device in Figure 3 may be the total pump device for an autonomous manure removal vehicle having a manure loading system relying on the conveying or scoping of manure into the tank, i.e. without a pump for creating suction in the tank when in cleaning mode. In autonomousmanure removal vehicles having a pump device for taking in manure into the tank, such as the embodiment of Figure 2, the depicted pump device may be part of the pump device 7, i.e. the pump or compressor 41 is a secondary pump to an air pump comprised in the pump device 7 as depicted. The secondary pump may be with its inlet 41 b connected to an independent outlet to ambient air and with its outlet 41a directly to an upper part of the tank 3, or be connected to one or both of the existing inlet 8 and outlet 9 also used by the air pump for pumping air out from the tank.

[0052] An alternative embodiment, suitable for use in a vehicle as depicted in Figure 2, is depicted in Figure 4A. In this embodiment, the pump device 7 has a vacuum circuit formed by an air pump 37 and a valve assembly with interconnecting piping. The secondary pump 41 is connected with an outlet 41a to the vacuum circuit. The vacuum circuit is positioned between the outlet pipe 9 and the intake pipe 8, with the valve assembly being arranged to define a first path for airflow therebetween along an air exchange opening connection opening 8a and an outlet connection opening 9a, and a second path for airflow together with the air pump 37 along an air pump outlet connection opening 39 and the outlet connection opening 9a.

[0053] Although various configurations of the valve assembly are possible, a particular compact design is schematically shown in Figure 4A, allowing the paths for airflow to be easily identified. In this compact design, the valve assembly has a valve housing 36 having the air exchange opening connection opening 8a, the outlet connection opening 9a and the air pump outlet connection opening 39, the valve housing enclosing a single valve 35 that is adapted to switch between the first path and the second path based on input from the controller. Alternative valve assemblies are foreseen, using more than the depicted single valve to achieve the necessary closing and opening of flow paths described here below for the various operational modes.

[0054] The pump device 7 in Figure 4A is further shown to have a filter 34 provided at the air pump inlet 37. This is an optional component, provided to prevent any manure that unintentionally exits the tank 3 via the air exchange opening 6 from entering the air pump 37.

[0055] When the vehicle 1 is operated in cleaning mode, the control device 10 controls the air pump 37 to pump air, while the valve assembly is set to have the second path for air flow in the vacuum circuit operational, causing the outward airflow along airflow path B as schematically shown in Figure 4B. Thus in cleaning mode, the air pump 37 is switched on while with an air pump inlet 37a in fluid connection with the intake pipe 8, and with an air pump outlet 37b in fluid connection with the outlet 9 via valve 35 in thevalve assembly. This first path for airflow in the vacuum circuit is closed off by the valve 35 when in cleaning mode and the secondary pump 41 is also switched off.When manure is to be discharged from the tank 3, the control device 10 switches the vehicle into dumping mode. In dumping mode, the air pump 37 is switched off, the second path for airflow is closed, and the secondary pump 41 is switched on, thereby generating a forced airflow along inward forced airflow path C, Ci into the tank via inlet pipe 8 as schematically shown in Figure 4C. Thus, the valve assembly is blocking the first path of airflow, i.e. the (direct) airflow path between the outlet 9 and the air exchange opening 6 which bypasses the air pump 37, both when in the cleaning mode and when in the dumping mode. The second path for airflow, i.e. the flow path through the air pump 37, may be closed through the air pump 37 comprising a valve that blocks the flow path when the pump is switched off. Additionally or alternatively, the valve assembly may be provided with an additional valve for closing off the second path for airflow.

[0056] Optionally, together with switching on the secondary pump 41 , the valve 35 may be switched to open the first path for airflow for a predetermined amount of time, such as for 5 seconds. By opening the first path for airflow, the forced airflow generated by the secondary pump 41 will first flow through an outward forced airflow path C, Cf via the valve 35 to the outlet 9, thereby cleaning the valve. After the predetermined amount of time has passed, the valve 35 is moved again to close off the first path for airflow, causing the airflow generated by the secondary pump 41 to be directed into the tank along inward forced airflow path C, Ci, resulting in creating an overpressure to push the manure out.

[0057] To let the vehicle hold on to the amount of manure inside the tank 3, such as when traveling to a dump site while the tank 3 is full, the air pump 37 may be switched off while retaining the valve assembly in a position that closes off the first path for airflow. The vehicle 1 is then controlled to operate in hold mode. The switched off air pump 37 then closes off the second path for airflow, ensuring no air exchanging via the air exchange opening 6 and thereby maintaining a substantially constant pressure inside the tank 3 until either the secondary pump 41 is switched on when the vehicle is in dumping mode, or the air pump 37 is switched on again to take in additional manure in cleaning mode. Optionally, as previously indicated, the first path of airflow may be opened for a predetermined amount of time, and / or until a tank level sensor indicates a particular value, before closing the first path or airflow and switching on the secondary pump 41 , to let manure that can flow out under gravity alone flow out.

[0058] An alternative pump device 7 is schematically shown in Figure 5A. The pump device 7 forms part of the manure loading system, i.e. the air pump 37 is used in cleaning mode for generating an under-pressure inside the tank 3 to suck manure into the tank 3. The pump system 7 consists of the vacuum circuit, comprising the air pump 37 and a valve assembly. Although various configurations of the valve assembly are possible, a particular compact design is schematically shown in Figure 5A, allowing the paths for airflow to be easily identified and resulting in a valve unit that is easy to handle. In this compact design, the valve assembly has a valve housing 36 having first and second air exchange opening connection openings 8a, 8b, an air pump inlet connection opening 38, an air pump outlet connection opening 39 and first and second outlet connection openings 9a, 9b. Inside the housing 36, a first valve 35a and a second valve 35b is provided, moveable to allow an airflow along one of a first path or a second path through the vacuum circuit. It will be obvious to the skilled person that the housing as schematically shown can be adapted to internally combine first and second air exchange opening connection openings 8a, 8b to a single air exchange connection opening and / or first and second air outlet connection openings 9a, 9b to a single air outlet connection opening, through one or more internal channels between the first and second valves 35a, 35b.

[0059] The air pump 37 is with an air pump inlet 37a, optionally via filter 34, connected to the air pump inlet connection opening 38and with an air pump outlet 37b to the air pump outlet connection opening 39.

[0060] When controlled to operate in cleaning mode, the valves of the valve assembly are moved into a position such that the first path for airflow is open and the air pump 37 is switched on, generating an airflow through the housing 36 from the first air exchange opening connection opening 8a and the air pump inlet connection opening 38, via the air pump 37, and through the housing 36 from the air pump outlet connection opening 39 and the second outlet connection opening 9b to the outlet 9. The airflow along the first path is schematically shown in Figure 5B.

[0061] When operated in dumping mode, the valves of the valve assembly are moved into a position such that the second path for airflow is open and the air pump 37 is switched on, generating an airflow through the housing 36 from the first outlet connection opening 9a and the air pump inlet connection opening 38, via the air pump 37, and through the housing 36 from the air pump outlet connection opening 39 and the second air exchange opening connection opening 8b to the air exchange opening 6. The airflow along this second path is schematically shown in Figure 5C.

[0062] In the valve assembly as schematically shown, both the first valve 35a and the second valve 35b are two-way valves, wherein the opening position for the first path is mutually exclusive to the opening position for the second path. The valve assembly is adapted to block any (direct) airflow path between the outlet 9 and the air exchange opening 6 which bypasses the air pump 37, both when in the cleaning mode and when in the dumping mode. Moreover, when the air pump 37 is switched off, regardless of the valve assembly being switched to the first path or the second path, any airflow between the outlet 9 and the air exchange opening 6 is blocked, such that a substantially constant pressure can be maintained for holding in manure without the use of the air pump 37 or an additional closing valve at the bottom of the tank 3.

[0063] A compacter alternative configuration to the valve assembly in Figure 5A is shown in the schematic embodiment of the pump device depicted in Figure 6A. Here, the valve assembly has a housing 36 enclosing one valve 35c. The housing 36 has an air exchange opening connection opening 8a, an air pump inlet connection opening 38, an air pump outlet connection opening 39 and an outlet connection opening 9a.

[0064] The single valve is a four-way valve, adapted to be movable to allow an airflow along one of the first path or the second path through the vacuum circuit.

[0065] When controlled to operate in cleaning mode, the valve 35c is moved such that the first path for airflow is open and the air pump 37 is switched on, generating an airflow through the housing 36 from the air exchange connection opening 8a and the air pump inlet connection opening 38, via the air pump 37, and through the housing 36 from the air pump outlet connection opening 39 and the outlet connection opening 9a to the outlet 9. The airflow along the first path is schematically shown in Figure 6B.

[0066] When controlled to operate in dumping mode, the valve 35c is moved such that the second path for airflow is open and the air pump 37 is switched on, generating an airflow through the housing 36 from the outlet connection opening 9a and the air pump inlet connection opening 38, via the air pump 37, and through the housing 36 from the air pump outlet connection opening 39 and the air exchange opening connection opening 8a to the air exchange opening 6. The airflow along this second path is schematically shown in Figure 6C.

[0067] The present invention has been described above with reference to a number of exemplary embodiments as shown in the drawings. It will be clear to a person skilled in the art that the scope of the invention is not limited to these examples, nor to the explicitly mentioned alternatives, but that a number of further variations and modifications thereof are possible without departing from the scope of the invention as defined in theattached claims. In particular, it may occur to the skilled person that alternatives could be used for the manure introduction device as a whole without deviating from the inventive concept presented herewith, as long as the tank 3 has an opening 15 in the bottom for discharging manure from and an overpressure can be generated above the manure-level in the tank, when the vehicle 1 is operated in discharging mode.

Claims

CLAIMS1 . Autonomous manure removal vehicle (1 ) adapted for removing manure from a floor of an animal space, comprising: at least two wheels (21 ), at least one electric motor device for driving at least one of the at least to wheels, and a control device (10) for controlling the manure removal vehicle (1) in at least a cleaning mode and a dumping mode, a manure storage tank (3) comprising a bottom provided with at least one opening (15) for supply of manure to and / or discharge of manure from the tank and an upper part provided with an air exchange opening (6) for the exchange of air between the interior of the tank and ambient air, and a manure loading system adapted for moving manure from the floor into the tank (3) when the vehicle is controlled to operate in the cleaning mode, characterised in that, the vehicle (1) further is adapted to, when the vehicle (1) is controlled to operate in the dumping mode, generate a forced airflow into the tank (3) via the air exchange opening (6), causing an over-pressure inside the tank (3).

2. The vehicle according to claim 1 , wherein the manure loading system comprises a pump device (7) comprising an air pump (37) and a valve assembly comprising at least one valve (35), the air pump (37) being provided with an air pump inlet (37a) in fluid connection with an interior of the tank (3) via the air exchange opening (6) and with an air pump outlet (37b) in fluid connection with an outlet (9) to ambient air of the vehicle (1), and the pump device (7) being adapted to be switchable between at least a cleaning mode and a dumping mode under the control of the control device (10), wherein, when in the cleaning mode, the pump device (7) has an airflow path (B) from the air exchange opening (6) via the air pump (37) to the outlet (9) for generating an under-pressure with respect to atmospheric pressure inside the tank (3) to suck manure into the tank (3) and wherein the valve assembly is adapted and controlled to block an airflow path from the outlet (9) to the air exchange opening (6) which bypasses the air pump (37), when in the cleaning mode and preferably also when in the dumping mode.

3. The vehicle according to claim 1 or 2, further comprising a pump or compressor (41) for generating the forced airflow, which is with a compressor outlet (41a) in fluid communication with the air exchange opening (6) at least when the vehicle is controlled in the dumping mode and which is with a compressor inlet in fluid communication with the ambient air.

4. The vehicle according to claims 2 and 3, wherein the compressor outlet (41a) is connected to the pump device (7), and wherein the pump device (7) is adapted to block the airflow path (B) from the air exchange opening (6) via the air pump (37) to the outlet (9) when the pump device (7) is in dumping mode.

5. The vehicle according to claim 2, wherein, when the vehicle (1) is controlled in the dumping mode, the valve assembly is adapted to have a forced airflow path (C) from the outlet (9) via the air pump inlet (37a), through the air pump (37), via the air pump outlet (37b) to the air exchange opening (6), and the air pump (37) is switched on to generate the forced airflow.

6. The vehicle according to claim 5, wherein the air pump inlet (37a) is in fluid connection with the air exchange opening (6) via a first closeable valve opening and in fluid connection with the outlet (9) via a second closeable valve opening, and wherein the air pump outlet (37b) is in fluid connection with the outlet (9) via a third closeable valve opening, and in fluid connection with the air exchange opening (6) via a fourth closeable valve opening.

7. The vehicle according to claim 6, wherein the pump device (7) is adapted such that the first valve opening being open is mutually exclusive to the second valve opening being open and / or the third valve opening being open is mutually exclusive to the fourth valve opening being open.

8. The vehicle according to claim 7, wherein the first closeable valve opening and second closeable valve opening are comprised in a single two-way valve (35a) and / or the third closeable valve opening and fourth closeable valve opening are comprised in a single two-way valve (35b).

9. The vehicle according to claim 7, wherein all of the first valve opening, second valve opening, third valve opening and fourth valve opening are comprised in a single four-way valve (35c).

10. The vehicle according to any one of claims 2 - 9, wherein the control device (10) is further adapted to control the vehicle (1) in a hold mode wherein the pump device (7) is arranged to block airflow to and from the air exchange opening (6) and preferably wherein the air pump (37) is switched off.

11. The vehicle according to any one of the preceding claims, further comprising a floor-scraping part (13) which, viewed in the normal forward direction of travel, narrows to a closed end, and wherein the at least one opening (15) for supply of manure to the tank (3), viewed in the normal forward direction of travel, is situated in front of the floorscraping part and is at least partly surrounded by the floor-scraping part.

12. Valve assembly for an autonomous manure removal vehicle (1) comprising a control device (10) adapted to control the manure removal vehicle (1), a tank (3) for storing manure and being provided with an air exchange opening (6), at least one opening (15) for supply of manure to and / or discharge of manure from the tank (3), and an air pump (37), the valve assembly comprising a housing (36) enclosing at least one valve (35a, 35b; 35c) and a motor which is connectable to the control device (10) for receiving control input and adapted for operating the at least one valve (35a, 35b; 35c) based on received control input, the housing (36) comprising an air exchange opening connection opening (8a, 8b; 8a), an air pump inlet connection opening (38), an air pump outlet connection opening (39) and an outlet connection opening (9a, 9b; 9a) and wherein the at least one valve ( 35a, 35b; 35c) is adapted to be moveable between a first mode defining a flow path through the housing (36) between the air exchange opening connection opening (8a) and the air pump inlet connection opening (38) and between the air pump outlet connection opening (39) and the outlet connection opening (9b; 9a), and a second mode defining a flow path through the housing between the outlet connection opening (9a) and the air pump inlet connection opening (38) and between the air pump outlet connection opening (39) and the air exchange opening connection opening (8b; 8a), wherein the movability of the at least one valve preferably is adapted to be controlled by the control device (10) of the vehicle (1).

13. The valve assembly according to claim 12, wherein the at least one valve comprises a first two-way valve (35a), arranged between the air pump inlet connection opening (38), the air exchange opening connection opening (8a) and the outlet connection opening (9a), and / or a second two-way valve (35b), arranged between the air pump outlet connection opening (39), the air exchange opening connection opening (8b) and the outlet connection opening (9b), wherein the at least one valve preferably consists of the first two-way valve and the second two-way valve.

14. The valve assembly according to claim 12, wherein the at least one valve is a single 4-way valve (35c), preferably a ball-valve comprising two through-channels, adapted to be moveable at least between the first mode and the second mode.

15. Method of operating an autonomous manure removal vehicle (1) adapted for removing manure from a floor of an animal space, comprising a control device (10) for controlling the manure removal vehicle (1) in at least a cleaning mode and a dumping mode, a manure storage tank (3) comprising a bottom provided with at least one opening (15) for supply of manure to and / or discharge of manure from the tank and an upper partprovided with an air exchange opening (6) for the exchange of air between the interior of the tank and ambient air, and a manure loading system adapted for moving manure from the floor into the tank (3) when the vehicle is controlled to operate in the cleaning mode, the method comprising:- collecting manure in the tank (3) by driving the vehicle through the animal space while operated in the cleaning mode at most until a maximum fill level of the tank is reached;- driving the manure removal vehicle (1) to a dump opening provided at floor level and adapted for receiving manure from the manure removal vehicle;- releasing manure from the tank (3) via the at least one opening for discharge of manure into the dump opening, wherein the step of releasing manure from the tank (3) comprises the vehicle being controlled to operate in dumping mode, thereby generating a forced airflow into the tank (3) via the air exchange opening (6) to raise the pressure inside the tank to a pressure that exceeds atmospheric pressure.

16. The method according to claim 15, wherein the generating a forced airflow into the tank (3) via the air exchange opening (6) comprises switching on a pump or compressor that is in fluid connection with the air exchange opening (6) via an outlet thereof.

17. The method according to claim 15 or 16, wherein the collecting manure in the tank comprises having an air pump (37) switched on and in fluid connection with the air exchange opening (6) and ambient air so as to generate an airflow from the interior of the tank (3) to the ambient air via the pump, thereby causing under-pressure with respect to atmospheric pressure inside the tank (3).

18. The method according to claims 16 and 17, wherein the generating of the forced airflow is performed with the air pump (37) and wherein the step of releasing manure from the tank (3) comprises the redirecting of the airflow generated by the air pump (37) to flow from the ambient air into the tank (3).

19. The method according to claims 15 - 18, wherein the step of driving the manure removal vehicle (1) to a dump opening comprises controlling the vehicle to operate in a holding mode, wherein the manure loading system is switched off and a substantially constant air pressure is maintained inside the tank (3).

Images