WO2015005865A1

WO2015005865A1 - Method and device for manure handling

Info

Publication number: WO2015005865A1
Application number: PCT/SE2014/050890
Authority: WO
Inventors: Emmanuel GEOFFROY
Original assignee: Delaval Holding Ab
Priority date: 2013-07-11
Filing date: 2014-07-11
Publication date: 2015-01-15
Also published as: GB201312452D0

Abstract

Method for manure handling in particular for manure clearing at an animal installation in an animal facility, aimed at reducing environmentally harmful gaseous emissions from an animal facility, in particular for reducing ammonia emissions. The method comprises the steps of: automatically detecting one or more ambient weather variables at said facility, automatically determining an environmental clearing requirement dependent on the value of said one or more weather variables, determining a current clearing requirement derived from the greater of said environmental clearing requirement and a default clearing requirement, automatically operating a manure clearing device in accordance with said current clearing requirement, wherein said one or more ambient weather variables includes temperature or humidity or wind speed. A determined clearing requirement may embody a requirement for clearing on an immediate and ongoing basis, or at intervals which correspond to prevailing conditions or at intervals corresponding to a user-set or regulation-imposed maximum time between clearing cycles, or all of these.

Description

METHOD AND DEVICE FOR MANURE HANDLING

The present invention relates to a method and apparatus for manure handling. In particular, a method for environmentally friendly manure handling in an animal facility such as an animal production facility or dairy milking facility is provided.

BACKGROUND

One aspect of improving manure handling and hygiene levels in a dairy animal installation concerns the regular removal of manure. Automated manure clearing in dairy animal installations has been previously known using a variety of devices. An automated system for manure removal and handling is known for example from WO201 1/095419. In recent years, increasing the efficiency and efficient energy consumption of farms and dairy animal facilities in general to meet the increasing competition has become even more important. Further, environmental concerns now are growing while environmental requirements are believed to be even stricter in the future, e.g. with a demand to minimize or reduce emission of methane and other greenhouse gases such as ammonia which may result from uncleared manure.

There is a desire to reduce the environmental impact from an animal facility. Further, there is still a need for methods and devices for improving the handling of manure at an animal facility.

SUMMARY

Accordingly, a method for manure clearing in an animal installation at an animal facility is provided, which installation comprises multiple animal boxes and automated manure clearing apparatus comprising a clearing device arranged to clear manure from among said animal boxes, said automated manure clearing apparatus comprising a control system configured to periodically actuate a clearing device; the method comprising the steps of: - automatically detecting one or more ambient weather variables at said facility,

- automatically determining a current environmental clearing requirement dependent on the value of said one or more ambient weather variables,

- determining a current clearing requirement derived from the greater of said current environmental clearing requirement and a current default clearing requirement,

- automatically operating said manure clearing device in accordance with said current clearing requirement,

wherein said one or more ambient weather variables includes temperature or humidity or wind speed.

According to the invention, an ambient weather variable may be one or more prevailing meteorological variables at and around an animal facility or at an animal installation at such a facility, an installation being capable of housing a herd comprising multiple animals. Preferably an installation may house more than eight animals, in most cases substantially more than eight animals. An installation may preferably be located at an animal facility which may comprise one or more installations. The detection of ambient weather variables according to the present invention is to be distinguished from very local measurements or determinations of weather or related variables prevailing at particular restricted locations or within parts of an apparatus or at an animal or at restricted, local parts of an installation. By way of example, an ambient weather variable according to the invention such as a temperature or humidity or wind speed or other variable is not intended to denote a local determination of the relevant variable at an animal or at a localized part of a piece of apparatus or at a localized part of an installation. A current environmental clearing requirement, be based at least partly upon one or more weather variables, may equally be termed environmental clearing requirement and may correspond to a maximum appropriate interval between successive clearing operations or to a minimum appropriate frequency of clearing operations. It may be expressed in any suitable manner or form and may for example be determined on the basis of a calculation using an algorithm and one or more variables, including at least one ambient weather variable. According to other exemplary embodiments, the environmental clearing requirement may be determined using look-up tables allowing a clearing schedule to be determined on the basis of the value of a single or more than one variable, including at least one ambient weather variable. An environmental clearing requirement may be defined in any suitable manner such as for example a clearing frequency e.g. number of clearing cycles per day or per hour or as a clearing interval such as e.g. a clearing cycle to be performed after a given number of minutes or hours since the previous clearing cycle. A clearing interval may be considered as a form of reciprocal of a clearing frequency. The operation of a clearing device of a clearing apparatus may in particular include actuating a clearing device such as a manure scraper for a predefined cycle of the scraper at all or parts of the relevant installation. According to the present invention, an animal facility includes at least one installation comprising animal boxes which may be of any type and which serve as locations with or without barriers where an animal may reside for a period of time. Manure clearing apparatus may be any suitable type of manure removal or clearing apparatus. One known type of manure clearing apparatus includes a clearing device in the form of a movable scraper which is moved along the ground in a relevant area pushing manure along a predetermined path e.g. to removal channels.

According to the invention, the method includes determining a current clearing requirement and operating a manure clearing device on the basis of a corresponding clearing frequency or clearing interval. This current clearing requirement may in particular correspond to a current environmental clearing requirement if, after a comparison with a current default clearing requirement, it is found that the current environmental clearing requirement exceeds the current default clearing requirement. In this context, the term "exceeds" is intended to denote a clearing requirement having a higher clearing frequency or lower clearing interval. On the other hand if, after a comparison between a current environmental clearing requirement and a current default clearing requirement, the current default clearing requirement would exceed the current environmental clearing requirement, then that default requirement would be implemented as part of the method, i.e. as the current clearing requirement. This situation may arise in case weather or other relevant conditions are benign as far as their effect on manure is concerned. An advantage of this aspect of the method of the invention is to ensure that an increased rate of manure clearing is implemented when necessary, e.g. if weather or other prevailing conditions would tend to increase ammonia or other gaseous or vapourous emissions from manure. However it also ensures that under benign prevailing weather or other conditions, the rate of manure clearing would be reduced, thereby saving energy. On the other hand, the reduction in the frequency of manure clearing operations would only go as far as a default level, perhaps prescribed by regulatory requirements or a default level deemed a minimum appropriate frequency by an operator. Accordingly, a default clearing frequency (minimum) or clearing interval (maximum) may be pre-set by a user in the form of a basic minimum default clearing requirement in order to ensure that under no circumstances could there be an unduly prolonged period without a clearing operation being carried out. Therefore, according to an aspect of the present invention, the step of automatically operating the manure clearing apparatus in accordance with the current environmental clearing requirement is performed conditional upon said current environmental clearing requirement necessitating a clearing device actuation frequency which is greater than a prevailing default clearing frequency.

Accordingly, the method of the invention includes measuring one or more ambient weather variables and determining an environmental clearing requirement dependent upon the value of the one or more measured ambient weather variables. The implemented clearing frequency may thereafter correspond to the determined environmental clearing frequency, if that frequency is greater than a preset or determined default clearing frequency. In some embodiments, the current number of animals present may be a factor in the determination of an appropriate environmental clearing requirement.

In some optional embodiments, a default clearing frequency may be calculated based on other prevailing conditions. In some embodiments, the method may include monitoring the number of animals currently present at a relevant animal installation. If the current number of animals present would exceed a threshold value, then the method may include making an adjustment to a default basic minimum clearing requirement, possibly in proportion to the number of animals present above a threshold level. In particular, an adjustment may be made in this situation by increasing the default clearing frequency or by reducing the current default clearing interval. The adjustment may be necessary because an increased number of animals present at an installation can be expected to lead to an increased rate of manure production and thereby to increased levels of emissions from manure, as well as a possible adverse effect on hygiene conditions at the installation. In alternative embodiments, the current number of animals present may be a detected environmental variable and may therefore, in association with at least one ambient environmental variable, be a factor in a determination of an environmental clearing requirement.

In other embodiments, the number of animals present may be a factor in the determination of a default clearing requirement, to be applied only if the measured ambient environmental variables would not necessitate a higher clearing frequency than the determined default frequency. Such a situation may arise for example where weather conditions are generally benign as far as ammonia or other gaseous emissions are concerned (e.g. low wind speeds, moderate temperature, high humidity, or any combination of these) but, for example when the installation is very full or where other conditions prevail such that a high level of emissions from manure can be expected.

In a further aspect, the method may include the step of defining an environmental coefficient representative of the detected value or values of one or more prevailing environmental variables, wherein the clearing requirement is determined dependent on the value of said environmental coefficient. According to this embodiment, the environmental coefficient may be a single value which represents multiple individual variables, e.g. multiple environmental variables, and which may be calculated using an algorithm. In certain aspects of the invention, the method may be a method for reducing gaseous emissions such as ammonia emissions at an animal installation. In that context, an environmental coefficient may be an ammonia index. Still alternatively or additionally, the environmental coefficient may be derived from a string of variables (x, y, z) etc. In some embodiments, the current clearing requirement may be derived from the environmental coefficient using look-up tables. In particular, the environmental coefficient may be a function of two or more or all of said detected weather variables. Accordingly, by way of example an algorithm which generates a coefficient from two or more variables may be used or any other suitable form for expressing the coefficient in terms of two or more variables may be used. According to the invention, the detected ambient weather variables may include one variable or any combination of one or more variables from among: ambient temperature, ambient humidity, or ambient wind speed. In further embodiments, an environmental coefficient such as an ammonia index may further include the current number of animals at a relevant installation as a variable.

According to a further particular aspect of the invention, the detected ambient weather variables may include temperature and may additionally include ambient humidity or ambient wind speed. In embodiments, the detected ambient weather variables may include ambient wind speed and may additionally include ambient humidity or ambient temperature. In embodiments, the detected ambient weather variables may include ambient humidity and may additionally include ambient wind speed or ambient temperature. In embodiments, an environmental coefficient may be representative of combined detected values of said temperature and wind speed and humidity. Additional variables are not excluded from an environmental coefficient such as current number of animals at a relevant installation. In some embodiments, an additional coefficient may be incorporated into a determination of a current clearing requirement. By way of example, a determination of a current clearing requirement may additionally incorporate making a determination of one or more animal related variables such as the number of animals present. Preferably, a basic minimum default clearing frequency which may be implemented in the method of the invention may be pre-set in a control system of the manure clearing apparatus. Still further alternatively or additionally, a default clearing frequency may be a minimum clearing frequency (e.g. one clearing per 'x' number of hours) which may for example be manually set by a user as a basic default minimum frequency. In some embodiments, if a current number of animals present exceeds a predetermined threshold, which threshold may for example be set by a user, then an adjusted default clearing frequency may be applied as the default frequency instead of a basic minimum default frequency.

According to further aspects of the invention, the determined current clearing requirement may define a determined minimum clearing frequency or a determined maximum clearing interval and operating the manure clearing apparatus in accordance with the current clearing requirement is carried out by actuating the clearing device in accordance with said determined current clearing frequency or determined clearing interval. In this context, a clearing interval may preferably denote a time period after an immediately preceding clearing and prior to a subsequent clearing. Accordingly, a clearing interval corresponds to a current clearing interval which is determined, according to the prevailing conditions, to represent the longest appropriate clearing interval, i.e. a lowest appropriate clearing frequency. A time period t_max may be defined as a period of time since a most recent clearing cycle after which a subsequent clearing cycle is required. A frequency can be derived from a knowledge of a relevant interval and a knowledge of the cycle time (t_c) for a single operation of the clearing device. t_max may suitably be expressed in any appropriate units such as for example seconds, minutes, hours or days. t_max may be considered to express a maximum upper threshold clearing interval because it represents the longest appropriate clearing interval under the prevailing conditions. This may be different from a default maximum clearing interval which may be implemented for example under benign weather conditions. A clearing frequency may be expressed in any suitable manner, for example as 1/(t_max+ t_a), where t_a denotes a cycle time of a clearing device. According to embodiments of the invention, a clearing apparatus may be controlled to be actuated after a time has passed since a latest previous clearing. According to other embodiments, a clearing requirement may be established from detected environmental variables by calculation using algorithms or by using look up tables. A clearing interval which corresponds to a clearing requirement imposed by weather or other environmental conditions may be designated t_e, while a clearing interval which corresponds to a default clearing requirement imposed by a user e.g. corresponding to a basic regulatory clearing frequency requirement may be designated t_max,_defauit- This may be alternatively expressed as a frequency F_min,defauit or F_BD- Hence, a clearing requirement t_max to be applied at any given time may for example at times correspond to t_max,defa_it or to t_e. Accordingly, a clearing requirement may be adapted in accordance with one or more prevailing weather variables or other variables. Moreover, when a clearing requirement is adjusted in response to more than one variable, then the clearing requirement to be applied may in particular reflect a combined effect of the relevant variables. By way of example, when an elevated value of a particular first variable would independently lead to a first adjusted clearing requirement, then if, at the same time, the prevailing value of a second variable would independently lead to a second adjusted clearing requirement, then the net combined effect of the first and second variables on the clearing requirement may be to lead to a third clearing requirement, different from the first or second clearing requirements.

According to alternative embodiments, a determined clearing requirement may define an immediate clearing requirement t_e = t₀, indicating a requirement to actuate a clearing mechanism immediately, to may in this context correspond to a clearing interval having a zero time value or a clearing frequency F which is at a maximum, e.g. the frequency may be equal to the maximum possible number of clearing cycles per unit time, such as per hour or per day. This may in particular result from a situation in which one or more detected weather or other variables or an environmental coefficient exceeds a predetermined critical threshold value (e.g. H_threshoid_> ¹ threshold Vthreshoid, Ethreshoid) for the respective variable H, T or V, or for a coefficient E. By way of example, it may be considered that at wind speeds or temperatures above a certain critical level, there is a need to immediately carry out clearing, irrespective of when the latest clearing was carried out. The same may be the case for example if a detected humidity level is below a lower critical threshold level. Any of these conditions may be associated with increased levels of gaseous emissions from manure. In this sense an immediate clearing requirement can be distinguished from a clearing requirement resulting from a situation in which an ongoing monitoring of weather or other conditions would result in a shortening of the required clearing interval from an initial value to a lower, non-zero value, thereby possibly triggering an immediate clearing cycle if the time elapsed since a previous clearing would then be greater than the newly determined, shorter clearing interval. An immediate clearing requirement may correspond to a situation in which the determined threshold interval arising from one or more detected variables is equal to zero. As mentioned, in embodiments, a coefficient E may be calculated on the basis of more than one variable, for the purpose of governing the appropriate level of a current clearing requirement. The algorithm which generates the value of the coefficient E may preferably be structured such that a threshold level Ethreshoid for the coefficient is met or exceeded in case a net combined effect of the relevant variables taken together would lead to a clearing requirement which would be triggered by breach of the relevant threshold level Ethreshoid- This may correspond to a need for an immediate clearing requirement or merely to an increased frequency (or shortened interval). The effect of two or more variables combined may be such as to lead to an adjustment which is greater or less than the corresponding adjustment which would be made for a single variable taken independently. In other words, the two or more variables may in some cases interact to produce an adjustment of a clearing requirement greater or less that the adjustment which would have been made in respect of just one variable taken alone. In other situations, two variables may move in respective directions, the net effect of which is that a change in one variable may completely or partly cancel out the effect of the change in the other variable. According to an optional aspect, the method may include continuously actuating a manure clearing device for as long as a particular predetermined critical threshold is exceeded, i.e. until all detected or determined conditions which triggered an immediate clearing requirement cease to prevail. As mentioned, an immediate clearing requirement may correspond to a clearing requirement for which the relevant time interval t_e between clearing cycles is zero. Preferably, after all detected or determined conditions which triggered an immediate clearing requirement cease to prevail, the method of the invention may include the step of operating a manure clearing apparatus at a reduced frequency, namely, at a frequency corresponding to a new determined clearing requirement associated with a newly detected set of weather condition variables. A subsequent determined clearing requirement may for example correspond either to a default basic minimum clearing frequency (maximum clearing interval) or corresponding to one of a determined default clearing frequency or a determined default clearing interval. In practice, the continuous operation of a clearing apparatus may correspond to a situation in which the method of the invention repeatedly generates a current clearing requirement which has a zero time interval between clearing cycles or which has a maximum clearing cycle frequency. Any subsequent determination of a current clearing requirement for a clearing cycle interval greater than zero or clearing cycle frequency of less than a maximum frequency thereafter leads to clearing cycles being operated with a certain pause time between successive cycles. This may come about for example if one or more relevant weather variables changes.

In an optional further aspect of the method of the invention, after all detected or determined conditions which triggered the said immediate clearing requirement cease to prevail the method may further include the step of operating the manure clearing device on the basis of a determined current clearing requirement corresponding either to a default minimum clearing frequency or corresponding to one of a determined clearing frequency or a determined upper threshold clearing interval.

In a still further optional aspect, the method may further comprise the step of monitoring current values of said one or more ambient weather variables, adjusting said current environmental clearing requirement correspondingly and operating said manure clearing apparatus by adjusting its operation to said current determined clearing requirement.

Optionally, the operation of a clearing apparatus may be interrupted in case a safety alert is generated by a safety system associated with said apparatus and control system. A safety system may in particular be a system for detecting obstacles, e.g. animals, in a path of a clearing apparatus.

Optionally, the method of the invention may include the step of monitoring current values of one or more environmental variables, adjusting a current clearing requirement correspondingly and operating a manure clearing apparatus by adjusting its operation to a current determined clearing requirement. In another aspect, the invention may comprise a control system configured for automatically operating a clearing apparatus at an animal installation according to the method of the invention, the control system comprising at least a processor and a storage element associated therewith, wherein the storage element incorporates executing instructions embodying said method. These executed instructions may be in the form of a stored, readable computer program.

In a yet further aspect, the invention comprises a clearing apparatus configured for operation at an animal facility, the apparatus comprising at least an automatic manure clearing device and a control system configured for operating the manure clearing device according to the method of the invention.

According to aspects of the invention, progressively higher ambient temperature values may in particular be associated with higher clearing device actuation frequencies. In other words, higher temperatures may generally give rise to increasing clearing requirements by way of greater clearing frequency or shorter intervals. Correspondingly, progressively higher ambient wind speed values may be associated with higher clearing device actuation frequencies. Progressively lower ambient humidity values may be associated with higher clearing device actuation frequencies.

The method and device of the present invention contributes to a more efficient operation of a dairy animal facility by controlling the clearing of the dairy animal facility to reduce the energy consumption and at the same time ensuring that environmental requirements are met. In other words, increased frequency of operation of a clearing device is only carried out when it is needed by virtue of environmental conditions which would worsen the ammonia emissions if manure were allowed to be left uncleared. When environmental conditions are benign with regard to ammonia emissions, then a lower or default clearing frequency may be implemented, thereby saving energy.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present invention will become readily apparent to those skilled in the art by the following detailed description of non-limiting exemplary embodiments of aspects thereof with reference to the attached drawings, in which:

Fig. 1 shows a flow chart of an exemplary method including optional aspects according to the invention, and

Fig. 2 shows a flow chart of an optional alternative aspect according to the invention, and

Fig. 3 schematically illustrates a control device according to aspects of the invention.

DETAILED DESCRIPTION

The figures are schematic and simplified for clarity, and they merely show details which assist in the understanding of aspects of the invention, while other details may have been left out. Throughout, the same reference numerals are used for identical or corresponding parts. The invention is not limited by any example or part thereof.

Different parameters may play a role in determining whether clearing is needed in a facility. Wind speed, temperature, humidity and other weather parameters influence the properties of manure and how much green house gas (methane etc) or ammonia is emitted from the manure/facility. Dry manure may be difficult to remove/clear thereby requiring more energy to remove it, and the emission of green gas or ammonia from the facility may be restricted due to regulations. When wind levels increase, so does the level of e.g. ammonia emission and emission of other gaseous substances. Further, there may be a desire to reduce the number of clearing cycles in a facility to reduce stress among the animals and also energy consumption. In other words, there may be environmental reasons for operating frequent cycles of a clearing apparatus, whereas economics may create an incentive to clear less frequently. A determination and control of an optimum amount of clearing should provide a balance between these competing incentives.

The weather data may include wind speed data, e.g. the weather data may include one or more wind speeds (Vi, V₂, V₃,...) indicative of overall wind speed, as detected at one or more different locations inside or outside the facility. The wind speed of a location may comprise magnitude of the wind speed and/or direction of the wind. It may be measured for example in meters per second or in any other standard unit of velocity and may be measured using known wind speed measurement devices.

The weather data may include temperature data, e.g. the weather data may include one or more temperatures (Ti, T₂, T_3l ) indicative of overall temperature measured at one or more different locations inside or outside the facility. It may be measured for example in degrees Celsius or in any other standard unit of temperature and may be measured using known temperature measurement devices.

The weather data may include humidity data, e.g. the weather data may include one or more humidities (H-i , H₂, H₃, ) indicative of overall humidity at the relevant facility as detected at one or more different locations inside or outside the facility. Humidity may be measured using known measurement devices such as hygrometer devices and may in particular be expressed in terms of relative humidity (preferably) or absolute humidity or even specific humidity. Preferably, a single measure for each variable (e.g. H) may be generated on the basis of more than one measurement (Hi, H₂, H₃, ).

Optionally, herd data may also be used as an additional measured variable for determining a clearing requirement, in particular, in relation to a default clearing requirement or in relation to an adjustment of a default clearing requirement. The herd data may include the number N of animals in a herd, i.e. the number of animals present at a relevant installation. It is known that the number of animals present may influence the amount of emissions from manure produced by the herd in any given time period. By including the number of animals in the data which is used for determining a clearing requirement, a more precise estimation or modelling of the emissions from manure is facilitated leading to improved control of clearing in the facility. Herd data, such as a number N of animals present, may be incorporated into the determination of an adjusted default clearing requirement or it may be incorporated into an overall determination of a clearing requirement, in addition to environmental factors. Fig. 1 illustrates an exemplary method according to aspects of the present invention. The method comprises monitoring ambient weather variables and collecting current data (X_c) indicative of current status at the animal facility or at an installation thereof. The data may include ambient weather data (Xweather) and may additionally include herd data (Xherd)- In the case illustrated, the number N of animals may be monitored on an ongoing basis. Data may be periodically collected relating to the current number of animals present N_c. Weather data (Xweather) may be monitored in the form of variables for temperature T or wind speed V or humidity H. Current values 7c, V_c, He etc. of the variables may be collected. Monitoring may be carried out by sensors in particular under the command of a control system. Measurements may be made on an ongoing basis such that a control device may sample the detected or measured values at predetermined intervals which may be short regular intervals or sensor measurements may be made at predetermined Intervals, which may be short regular intervals and which may be controlled by a control device. Further, the method comprises determining a current environmental clearing requirement based on one or more measured weather variables. Preferably, in optional embodiments, this may involve determining at least one clearing criterion (Y^ Y₂, Y3, YN) for example including a first clearing criterion Y-i and/or a second clearing criterion (Y₂), the clearing criteria being indicative of clearing requirements. The clearing criteria may be based on the measured data and may include any additional relevant factors. A first clearing criterion (Y-t) may be a maximum permitted time (t_max, default) (or corresponding to min.defauit or ^BD) between two consecutive clearing cycles, i.e. the maximum time difference between the end (ti) of a most recent, or first clearing cycle and the start (t₂) of an immediately subsequent or second clearing cycle, which first clearing criterion may for example correspond to a clearing requirement imposed by regulatory standards requiring a basic minimum clearing frequency FBD- This may also be called a basic default maximum permitted time between clearing cycles (t_max, default)- In alternative embodiments, a default clearing requirement may be set or determined separately and may prevail only in case a clearing requirement determined from environmental measurements would tend to require a lower clearing frequency than the pre-set basic or determined minimum default clearing frequency.

A second clearing criterion (Y₂) may be an optimal maximum time (t_e) between two consecutive clearing cycles, which second clearing criterion may for example correspond to a clearing requirement derived from the detected value of one or more monitored variables at the installation such as maybe temperature or wind speed or humidity. The second clearing parameter Y₂ may be given as:

Y2 = t_e = f{X) (1)

This may be alternatively expressed as:

Y₂ = FcB = f(.X

where f[X) is a time function of the working data X and returning the optimal maximum time t_ept between two consecutive clearing cycles, where (X) may be an algorithm incorporating one or more detected variables x, y, z etc.

A clearing requirement C derived from said first and second clearing criteria Y₂ may be given as:

This may be alternatively expressed as:

where f(X) is a time function derived from the working data X and returning the currently required optimum maximum time t_e between two consecutive clearing cycles (which may also correspond to F_CE, denoting a current default clearing frequency) and wherein t_max,defauit (^BD) may be a default regulatory value or it may be selected and set by a user, thereby enabling a user or the control system to set a default maximum time between consecutive clearing cycles. In this case, the value of C corresponds to a currently determined maximum time interval (minimum frequency) between consecutive clearing cycles, which may also be expressed as t_max (or FCE)-

A clearing cycle may be initiated if an elapsed time (At), e.g. since the start or end of the latest clearing cycle is larger than the lesser of either the maximum permitted time t_max,defauit or the optimum maximum time t_e between two consecutive clearing cycles, i.e. if At>t_max,defauit or if At>t_e. In other words, if wind speed is monitored as a sole defining variable according to the invention then if, at a given time when a detection is carried out, detected wind speed rises to an extent such that a determined clearing criterion corresponding to wind speed would be fulfilled and would necessitate a shorter clearing interval than a default maximum interval, then the clearing requirement to be applied at the said given time will be adjusted to that required clearing interval. Similarly, where another variable is selected as a defining variable, or where multiple variables or coefficents E are selected as defining variables for a clearing requirement to be determined, then according to the method of the invention, a clearing interval to be applied at any given time may correspond to the shortest relevant clearing interval. This shortest relevant clearing interval at any given time may be that which is associated with a clearing criterion which generates the shortest interval on a comparison between respective relevant clearing criteria, and based on the latest detected or determined values of relevant variables or coefficients which underlie the chosen clearing criteria. So, if for example humidity underlies a clearing criterion Y_n, then after a significant detected decrease in the ambient humidity level, causing increased evaporation of liquids or emission of gases or vapours from manure on an installation floor (and thereby increasing ammonia or other gaseous release, while at the same time increasing manure viscosity), then the clearing criterion in question may correspond to the shortest determined clearing interval t_e. This has the effect of lowering the maximum determined clearing interval to that particular level thus triggering one or more clearing cycles at intervals imposed by those prevailing low humidity conditions. This remains the case, until either the ambient humidity level rises to an extent sufficient for the humidity level no longer to generate the shortest of the intervals underlying the relevant clearing criteria, or until a different detected variable generates an even shorter clearing interval than does the prevailing humidity level. In all cases, t_c (or Fc) - the current relevant clearing requirement - corresponds either to the default maximum permitted interval t_max,defauit (FBD), or to that determined interval (or frequency FCE) which is associated with a particular variable or coefficient, whichever generates the shortest among the relevant clearing intervals.

A third clearing criterion (Y₃) may for example correspond to any particular measured variable which lies in excess of or below a relevant predetermined threshold value for that variable, in which case a clearing interval time set at zero (i.e. t₀) would apply such that an immediate clearing action may be initiated and maintained for as long as the particular clearing criterion is fulfilled (in this case Y₃₎ but optionally, any other relevant clearing criterion associated with an immediate clearing requirement). The term Y₃ may thereby be said to define a clearing imperative.

ff for f{X) > F_BD

d

In the above example for a clearing requirement C, the term Y₃ may be complemented by any other relevant clearing imperative.

Similarly, a further clearing criterion e.g. Y₄ may be defined by a coefficient E representing an ammonia emission potential or an emission potential of any other greenhouse gas or pollutant such as methane or methanol. The coefficient may take into account any relevant variables such as one or more environmental variables, optionally combined with one or more herd variables such as current number Nc of animals present if the number of animals present Nc is above a predetermined threshold Λ/j_h· The interaction of more than one variable as part of a calculated coefficient E may lead to a clearing requirement FCE which is different from the clearing requirement which would apply in respect of the prevailing value of any single variable within the coefficient. The optional determination of an environmental coefficient E is shown inside a broken line box.

In embodiments, the value of a time interval or required clearing frequency corresponding to a potential clearing requirement CE may be read out from a stored look up data table which is set up for a given clearing criterion.

Further, the method comprises initiating clearing in the animal installation if a clearing requirement F_c based on associated variables or on an associated coefficient is fulfilled, i.e. if a clearing requirement Fc dictates that at a present moment in time, initiation of a clearing device is due. As can be seen from Fig. 1 , the steps of monitoring relevant variables, collecting measured or detected values and determining therefrom a current clearing requirement F_CE are preferably intended to be performed repeatedly and at short intervals, although the frequency of data sampling (i.e. of monitoring or collecting measurement data) may be selected and varied. Preferably, the method of the invention maintains a current and relevant clearing requirement F_c as a result of the repeated monitoring of variables and determination of the clearing requirement FCE corresponding to the prevailing current conditions.

Still with reference to Fig. 1 , after collecting the values of one or more current ambient weather variables H_c, 7c, V_c etc, and after optionally having regard to whether a current number of animals present N_c exceeds a threshold value N_Ti , the method includes determining, based thereupon, an appropriate environmental clearing frequency F_CE- A comparison is then made between a default clearing requirement corresponding to a frequency F_CD and the determined clearing requirement corresponding to a frequency F_CE- If the currently required environmental clearing frequency FCE is greater than the currently applicable default clearing frequency FCD_> then the clearing device is operated in accordance with a current clearing requirement Fc, which corresponds to the determined environmental clearing requirement FCE- If on the other hand the currently required environmental clearing frequency F_CE is less than the currently applicable default clearing frequency FCD_> then the clearing device is operated in accordance with a currently applicable default clearing frequency FCD. In Fig. 1 , the dotted connecting lines may be considered to represent a flow of information and not necessarily a strict sequence of method steps.

As can be seen from other optional method steps shown in Fig. 1 , a currently applicable default clearing frequency F_CD, may correspond in some cases to a previously set or otherwise predetermined basic minimum default clearing requirement F_BD- This would be the case if no other prevailing conditions, in particular measured conditions, would necessitate a higher default clearing requirement. Also illustrated by way of example in Fig. 1 is the optional method step of adjusting a basic minimum default clearing requirement FBD in case a currently determined number of animals present N_c would exceed a predetermined lower threshold value N_Th. In such a case, the applicable current default clearing requirement F_CD would be greater than the basic minimum default clearing requirement F_BD- This is further illustrated separately with reference to Fig. 2, in which an adjusted basic default frequency FAD is calculated in case a current number of animals present N_c exceeds a threshold number, in which case a current default clearing requirement FCD is set equal to the adjusted default value F_AD-

As mentioned, optionally, the determination of a current environmental clearing frequency F_CE may additionally take account of a current number of animals Nc, which may optionally be monitored as part of the method of the invention. Also visible in Fig. 1 is a method option wherein a current environmental clearing requirement FCE may be calculated on the basis of a coefficient E derived from one or more measured variables such as weather or herd variables. It should be noted that in accordance with aspects of the invention, an environmental clearing requirement FCE may be derived from either determined coefficients £ or from measured values V_c, T_c, H_c of one or more relevant variables V, T, or H, or both. By way of example, where herd data is gathered in the form of a value of a number N of animals, a herd coefficient may be calculated from that value and may be utilized for the purpose of determining a corresponding clearing requirement FCE (or t_et). It may also be that when a number of animals at an installation exceeds a given number, which may optionally be set by a user, then a clearing requirement with a zero time interval to may be applied, i.e. an immediate clearing requirement may apply. This may in particular occur in case another relevant variable, such as a weather variable exhibits a current value which would tend to necessitate a greater current clearing requirement. In the context of the examples discussed above, a clearing criterion based on a herd variable may be denoted for example as Y₆, whereas a clearing criterion based on a herd coefficient may be denoted for example as Y₇ etc.

As already indicated, in aspects of the invention, by way of example, one or more clearing criteria may be based upon measured weather variables while one or more further clearing criteria may be based on herd variables. In particular, where a clearing criterion is based on more than one variable, then a coefficient incorporating those variables may preferably be determined. One or more clearing criteria may be based upon a single variable, perhaps in addition to clearing criteria which are based on a coefficient. By way of example, a clearing requirement may be determined based on a series of clearing criteria, which clearing criteria may include an environmental coefficient, based upon, say, temperature T and humidity H and wind speed V, while a further clearing criterion may correspond to a particular value of any one of temperature T, humidity H or wind speed V. The effect of this would be to ensure a current clearing requirement which is at all times adapted to overall environmental conditions while also allowing for a specific, single-variable related clearing requirement under certain predetermined conditions. This may be an immediate clearing requirement based on, say a predefined high temperature threshold being exceeded and may serve to prevent manure from evaporating due to heat.

The present invention thereby ensures an adapted clearing requirement capable of ensuring low environmental impact and also responding to regulatory or user-set imperatives, overall weather or herd conditions and immediate clearing requirements relating to critical levels of any individual relevant variable.

Fig. 3 illustrates an exemplary control device 100 according to the invention. The illustrated control device 100 comprises a processor 102, a data storage element in the form of a memory 104 connected to the processor 102, and a user interface 106 connected to the processor 102. A user may implement the invention using an easy to use user interface for a controller capable of carrying out the method of the invention and associated with apparatus according to the invention. Suitable manure clearing devices may be of any known type and may in particular take the form of autonomous scraping vehicles or they may take the form of one or more floor scrapers which run along rails. Optimal conditions can thereby be maintained inside an installation without the need to run clearing systems at times when they are not effective. Systems such as a clearing system may nevertheless be operated manually by means of a manual override if required. The controller may in particular be associated with wind, temperature and humidity sensors as well as herd count sensors or herd count database information. The sensors may be outside or inside an installation or both. The control system, in addition to offering automated control of manure clearing at an installation based on environmental or herd variables, may additionally allow a user to select a pre- programmed fixed mode of operation of a clearing apparatus according to a fixed time schedule.

The control system and method allow a clearing apparatus to operate at a minimum required frequency when environmental conditions are fair, and they ensure progressively increased clearing frequency in response to progressively adverse environmental conditions, wherein the term adverse in this context denotes meteorological conditions which tend to increase harmful effects on the environment of manure lying uncleared for any length of time. As such, the invention allows to operate at a low clearing frequency when conditions allow, and applies a progressively higher clearing frequency when environmental or meteorological conditions are progressively more adverse.

According to the inventions, a determined clearing requirement may embody a requirement for clearing on an immediate and ongoing basis, or at intervals which correspond to prevailing conditions or at intervals corresponding to a user-set or regulation-imposed maximum time between clearing cycles, or all of these.

An animal installation may for example be a barn. In one optional embodiment according to the method of the invention, when the ambient temperature rises above a threshold level of 25 degrees Celsius, the clearing device may be operated continuously. In embodiments, there may be a progressive increase in the cleaning intervals below this temperature. In other embodiments, there may for simplicity be no progressive increase in the cleaning intervals below this temperature. Alternatively, a threshold for the temperature level may be 20 degrees or 28 degrees or 30 degrees. In still further optional embodiments, when the wind speed increases above a certain threshold, the clearing device is operated continuously. There may optionally be no progressive increase in the cleaning intervals below this wind speed. In other embodiments, progressively higher wind speeds may generate progressively higher clearing requirements up to a maximum threshold level corresponding to a continuous clearing requirement. A suitable threshold wind speed may, in embodiments, correspond to a speed of 5m/s. Alternatively, the threshold may lie around 8m/s or 12m/s. In particular, when any of the applicable thresholds has been reached, operation of a clearing device may be continuous until all relevant parameters drop below their thresholds. In embodiments, there may be no interaction between the thresholds. In other embodiments e.g. the wind speed threshold may be adapted based on the temperature, the temperature threshold may be adapted based on the humidity, etc. Therefore, as can be appreciated, the present invention envisages the use of simple thresholds, either alone or in combination.

It should be noted that in addition to the exemplary embodiments of the invention shown in the accompanying drawings, the invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

Claims

1. Method for manure clearing in an animal installation at an animal facility, which installation comprises multiple animal boxes and automated manure clearing apparatus comprising a clearing device arranged to clear manure among said animal boxes, said automated manure clearing apparatus comprising a control system configured to periodically actuate said clearing device; wherein said method comprises the steps of:

- automatically detecting one or more ambient weather variables at said facility,

2. Method according to claim 1 further including the step of defining an environmental coefficient representative of said detected values of said one or more weather variables, and wherein said current environmental clearing requirement is determined dependent on the value of said environmental coefficient.

3. Method according to claim 2, further including the step of monitoring the number of animals present at said installation, wherein said environmental coefficient is determined additionally in dependence on the current number of animals at said installation.

4. Method according to any preceding claim, further comprising said step of determining said current default clearing requirement on the basis of a predetermined basic minimum clearing requirement.

5. Method according to claim 1 or 2, further including the step of monitoring the number of animals present at said installation, and further comprising the step of determining said current default clearing requirement in dependence on the current number of animals at said installation.

6. Method according to claim 5, wherein said current default clearing requirement is derived by adjusting a predetermined basic minimum default clearing requirement if said current number of animals at said installation exceeds a threshold value.

7. Method according to any preceding claim, wherein said one or more environmental variables includes temperature and additionally includes ambient humidity or wind speed.

8. Method according to any preceding claim, wherein said determined current clearing requirement defines a determined optimum clearing frequency or determined optimum clearing interval and wherein operating said manure clearing device in accordance with said clearing requirement is carried out by actuating said clearing device in accordance with said determined current clearing frequency or determined optimum clearing interval.

9. Method according to any preceding claim, wherein if one or more of said detected ambient weather variables or said environmental coefficient exceeds a critical threshold value for the respective variable or coefficient, then said determined current clearing requirement defines an immediate clearing requirement, and wherein the step of operating said manure clearing device in accordance with said immediate clearing requirement is carried out by immediately actuating said clearing apparatus.

10. Method according to claim 9, wherein said method includes continuously actuating said manure clearing apparatus until all detected or determined conditions which triggered the said immediate clearing requirement cease to prevail.

1 1. Method according to claim 9 or 10, wherein said immediate clearing requirement is triggered by

a detected ambient temperature above a predetermined threshold temperature, or by

a detected ambient wind speed above a predetermined threshold wind speed value, or by

a detected ambient humidity level above a predetermined threshold humidity level value.

12. Method according to any preceding claim, wherein said method is a method for reducing environmentally detrimental gaseous emissions at an animal installation.

13. Method according to any preceding claim, wherein said method is a manure-clearing method for reducing ammonia emissions at an animal installation.

14. Control system configured for automatically operating a clearing apparatus at an animal installation according to the method of any previous claim, said control system comprising a processor and a storage element associated with said processor, said storage element incorporating executing instructions embodying said method.

15. Clearing apparatus configured for operation at an animal facility, said apparatus comprising an automatic manure clearing device and a control system configured for operating said manure clearing device according to the method of any previous claim.