MEASUREMENT SYSTEM AND METHOD FOR DOSING DISTRIBUTION MATERIAL

Abstract

The invention relates to a dosing system (10) for an agricultural spreading machine (100), comprising: an equipment arrangement (16) having at least one flow generator (18, 20, 42) for generating a feed air flow (FLS) flowing in the feed direction and a dosage air flow (DLS); a dosing device (26, 26a, 26b), which is designed to dose spreading material using a dosage air partial flow (DLTS) generated from the dosage air flow (DLS); and a distribution system (22), by means of which spreading material can be fed, using the feed air flow (FLS), from a storage container (12, 14) to the dosing device (26, 26a, 26b).

Description

1 / 19 MEASUREMENT SYSTEM AND METHOD FOR Dosage of distribution material

[0001] The invention relates to a measuring system for an agricultural distribution machine according to the preamble of claim 1 and to a method for measuring distribution material according to the preamble of claim 11.

[0002] Conventional measuring systems typically comprise a device assembly with at least one flow generator. The device assembly generates a carrier airflow in a transport direction and a measuring airflow. A measuring device then measures the dispensing material to be dispensed using a partial measuring airflow generated from the measuring airflow. The dispensing material is transported from a storage container to the measuring device using the carrier airflow.

[0003] With known metering systems, there is a risk, especially when metering fine seeds such as rapeseed, that the dispensing material will flow in the opposite direction to the conveyor airflow and therefore towards the flow generator if the conveyor airflow is reduced or absent. The flow generator may be damaged by the return of the dispensing material. There is also a risk that the dispensing material may be unintentionally forced out of the flow generator and thus end up in the field in an uncontrolled manner.

[0004] If the conveyor airflow is generated hydraulically by the tractor's hydraulic system, in some operational situations, such as when hydraulically lifting an implement conveyor from the distribution machine, there may not be enough power. Petition 870250082310, dated 12 / 09 / 2025, page 10 / 43 2 / 19 sufficient hydraulics to generate a sufficient conveyor airflow, which may result in material backflow through the metered airflow.

[0005] The underlying task of the invention is therefore to prevent the unintentional backflow of the distribution material against the direction of transport when the airflow from the conveyor is reduced or absent.

[0006] The task is solved by a measuring system of the type mentioned above, wherein the measuring system according to the invention comprises a backflow prevention device whereby, in the event of reduced or absent conveyor airflow, the introduction of distribution material located in the distribution system into the flow generator of the device assembly can be prevented by means of one or more measuring airflows flowing in the opposite direction to the conveying direction.

[0007] Damage to the flow generator caused by backflow of the dispensing material can be effectively prevented by the backflow prevention device. Accidental expulsion of the dispensing material from the flow generator is also prevented. Reduced or absent conveyor airflow may occur due to an interruption or restriction in conveyor airflow generation or due to a defect, for example, a pipe defect or a leak. Reduced or absent conveyor airflow with simultaneous active metering airflow may occur, especially when switching airflow generation on and off. During normal operation, a partial conveyor airflow generated by the conveyor airflow and a partial metering airflow generated by the metering airflow are combined in the dispensing device, so that the dispensing material is conveyed in Petition 870250082310, dated 12 / 09 / 2025, page 11 / 43 3 / 19 direction of the agricultural field through combined airflow. The flow generator can be supplied as a blower, for example.

[0008] In a preferred embodiment of the measuring system according to the invention, the anti-reflux device comprises at least one movable or deformable shut-off valve, by means of which a free-flow cross-section through the anti-reflux device can be partially or completely closed. The anti-reflux device is preferably a passive component that cannot be controlled by an electronic control device. The anti-reflux device may comprise one or more pivoting shut-off valves. The at least one movable shut-off valve is preferably rotatable in the flow cross-section. When the shut-off valve is fully open, it is aligned parallel to the flow direction, for example. The shut-off valve may be provided as a disc-shaped element. The shut-off valve may be a centric shut-off valve. The shut-off valve may be a single, double, or triple eccentric shut-off valve.The anti-reflux device may comprise one or more stops for one or more shut-off valves. The shut-off valve may be made of an elastically deformable material. In this case, the free-flow cross-section is released and closed by the deformation of the shut-off valve. The anti-reflux device may be, for example, a check valve.

[0009] In another preferred embodiment of the measuring system according to the invention, the backflow prevention device is configured to be actuated by the airflow passing through the backflow prevention device. When the backflow prevention device flows in the transport direction, the backflow prevention device is preferably in an open state, Petition 870250082310, dated 12 / 09 / 2025, page 12 / 43 4 / 19 in which the backflow prevention device can be traversed by an airflow composed of distribution material. When the backflow prevention device flows through or in the opposite direction to the transport, the backflow prevention device is in a closed state, in which the distribution material cannot flow through or pass through the backflow prevention device. In the closed state, the backflow prevention device may also be impassable to the airflow, or the airflow may continue to flow through the backflow prevention device, particularly in a highly restricted manner, so that there is high resistance to flow against the transport direction.The backflow prevention device may comprise a blocking device, in particular a blocking valve, which has a flow resistance dependent on the direction of conveyance, so that the blocking device can be actuated, preferably exclusively, by the airflow passing through it. For example, such a blocking device may have a low flow resistance in the direction of flow, so that the conveyor airflow can pass through it with at least approximately no loss. In the opposite direction to the flow direction, however, the blocking device may have a high flow resistance, so that an airflow containing the distribution material is impeded.

[0010] In another preferred embodiment of the measuring system according to the invention, the backflow prevention device comprises an actively controllable actuator for opening and / or closing the backflow prevention device. The actuator may be a controllable actuator. The actuator may be an actuated actuator. Petition 870250082310, dated 12 / 09 / 2025, page 13 / 43 5 / 19 electrically, pneumatically or hydraulically. In this embodiment, the backflow prevention device can also be used as an actively controllable throttling device to regulate airflow in the transport direction and against the transport direction.

[0011] In another preferred embodiment of the measuring system according to the invention, the distribution system comprises a main distribution unit into which the distribution material and the conveyor airflow can be introduced, and which is configured to distribute the distribution material to several partial conveyor airflows generated from the conveyor airflow. The main distribution unit preferably comprises at least one air inlet for the conveyor airflow and several air outlets for the partial conveyor airflows. In addition, the main distribution unit preferably comprises a material inlet opening for the distribution material.The main dispensing unit is preferably located below a storage container for the dispensing material, so that the dispensing material can enter the main dispensing unit through the material inlet opening under the influence of gravity.

[0012] In another preferred embodiment of the measuring system according to the invention, the device assembly comprises a transport airflow generator for generating the transport airflow and a measuring airflow generator for generating the measuring airflow. The anti-reflux device is preferably arranged between the transport airflow generator and the measuring airflow generator. Petition 870250082310, dated 12 / 09 / 2025, page 14 / 43 6 / 19 The device assembly size and the main distribution unit of the distribution system. The transport airflow generator is preferably a transport air blower. The measuring airflow generator is preferably a measuring air blower.

[0013] Furthermore, a measuring system according to the invention is preferable, in which the anti-reflux device is arranged between the main distribution unit of the distribution system and the measuring device. In this case, the respective partial airflows of the conveyor can be divided into several, for example, two, partial airflows of the conveyor by means of a dividing device. The dividing device can be, for example, a Y-shaped piece. The anti-reflux device can be integrated into the dividing device.

[0014] Furthermore, a measuring system according to the invention is advantageous because the device assembly comprises a flow generator to generate a main airflow and a flow divider to generate the conveyor airflow and the measuring airflow from the main airflow. The flow divider may comprise one or more switches or flaps to divide the main airflow into conveyor airflow and measuring airflow. In this case, it may occur that, at a specific position of the switch or flap, a pronounced measuring airflow is generated and, at the same time, a reduced or non-existent conveyor airflow, so that a reverse material flow may occur in the opposite direction to the conveyor. In this case, the anti-reflux device can be used to prevent the distribution material in the distribution system from entering the flow generator of the device assembly. Petition 870250082310, dated 12 / 09 / 2025, p. 15 / 43 7 / 19

[0015] In another preferred embodiment of the measuring system according to the invention, the anti-reflux device is arranged between the flow divider of the device assembly and the main distribution unit of the distribution system, or between the flow generator of the device assembly and the flow divider of the device assembly. If the anti-reflux device is arranged between the flow divider of the device assembly and the main distribution unit of the distribution system, a reverse material flow does not enter the flow divider of the device assembly and, therefore, also does not enter the flow generator due to the anti-reflux device.If the anti-reflux device is placed between the flow generator of the device assembly and the flow divider of the device assembly, the dispensing material may enter the flow divider of the device assembly in case of reverse material flow, but not the flow generator of the device assembly.

[0016] Furthermore, a measuring system according to the invention is preferred, in which the measuring device is provided as an overpressure-operated measuring device. The measuring device may comprise a rotationally driven measuring rotor. The measuring rotor may be a measuring disc or a measuring drum. The measuring device may be an overpressure-operated separating device. The separating device may comprise a rotationally driven separating disc or a separating drum.

[0017] The task underlying the invention is further solved by a method of the type mentioned at the beginning, in which, within the scope of the method according to the invention, the introduction of distribution material located in the distribution system in the generator of Petition 870250082310, dated 12 / 09 / 2025, page 16 / 43 8 / 19 The flow of the device assembly is prevented in the event of reduced or absent carrier airflow by means of one or more partial measuring airflows flowing in the opposite direction to the transport direction by means of an anti-reflux device in the measuring system. The method according to the invention can, for example, be implemented with a measuring system according to one of the embodiments described above. With regard to the advantages and modifications of the method according to the invention, therefore, reference is made first to the advantages and modifications of the measuring system according to the invention.

[0018] In a preferred embodiment of the method according to the invention, the backflow prevention device is actuated by the airflow passing through the backflow prevention device. The closed state of the backflow prevention device preferably depends on the direction of the airflow flowing through or into the backflow prevention device. Alternatively or additionally, an actuator of the backflow prevention device is actively controlled to open and / or close the backflow prevention device.

[0019] In another preferred embodiment of the method according to the invention, the distribution material and the conveyor airflow are introduced into a main distribution unit of the distribution system, which distributes the distribution material into several partial conveyor airflows generated from the conveyor airflow. Preferably, backflow of the distribution material is prevented by means of a backflow prevention device between a conveyor airflow generator of the device assembly and the main distribution unit of the distribution system. Alternatively, Petition 870250082310, dated 12 / 09 / 2025, page 17 / 43 9 / 19 The backflow of the distribution material is prevented by means of the backflow prevention device between the main distribution unit of the distribution system and the measuring device.

[0020] The method according to the invention is further advantageously developed, since the device assembly comprises a flow generator to generate a carrier airflow, wherein the carrier airflow and the measuring airflow are generated from the main airflow by means of a flow divider. Backflow of the distribution material is prevented by means of the anti-backflow device, preferably between the flow divider of the device assembly and the main distribution unit of the distribution system. Alternatively, backflow of the distribution material is prevented by means of the anti-backflow device between the flow generator of the device assembly and the flow divider of the device assembly.

[0021] Preferred embodiments of the invention are explained and described in more detail below, with reference to the accompanying drawings. These show:

[0022] Fig. 1 is a dispensing machine with a measuring system according to the invention in a schematic representation;

[0023] Fig. 2 is a measuring system according to the invention in a schematic representation;

[0024] Fig. 3 is an additional measuring system according to the invention in a schematic representation;

[0025] Fig. 4 is an additional measuring system according to the invention in a schematic representation;

[0026] Fig. 5 is an additional measuring system according to the invention in a schematic representation; Petition 870250082310, dated 12 / 09 / 2025, page 18 / 43 10 / 19

[0027] Fig. 6 is a schematic representation of a main distribution unit including a backflow prevention device of a measuring system according to the invention;

[0028] Fig. 7 is a backflow prevention device of a measuring system according to the invention in an open state in a schematic representation; and

[0029] Fig. 8 is a schematic representation of the backflow prevention device shown in Fig. 7 in the closed state.

[0030] Fig. 1 shows an agricultural distribution machine 100, by means of which two different spreading materials, for example, seeds and fertilizers, can be distributed in an agricultural field.

[0031] The agricultural distribution machine 100 is supplied as an attachment and can be coupled to a towing vehicle, such as a tractor, by means of a drawbar. The drawbar is connected to the main frame 102 of the distribution machine 100. The main frame 102 carries the storage containers 12 and 14 of a measuring system 10 of the distribution machine 100. The storage containers 12 and 14 can be used to transport the distribution material to be applied in the agricultural field. For example, granular fertilizers can be transported in storage container 12. For example, seeds can be transported in storage container 14.

[0032] The main structure 102 is connected to an implement conveyor 104 of the distribution machine 100. On the implement conveyor 104, several depositing devices are arranged side by side, by means of which a measured quantity of the distribution materials transported in the storage containers 12 and 14 can be deposited in the agricultural field. The Petition 870250082310, dated 12 / 09 / 2025, page 19 / 43 11 / 19 deposition devices can be provided, for example, as seed furrow openers and fertilizer furrow openers, wherein the seed furrow openers and fertilizer furrow openers can be, for example, disc furrow openers or toothed furrow openers.

[0033] The measuring system 10 of the dispensing machine 100 includes a device set 16 comprising a conveyor airflow generator 18 and a measuring airflow generator 20. The conveyor airflow generator 18 generates a conveyor airflow FLS flowing in the conveying direction. The measuring airflow generator 20 generates a measuring airflow DLS. Several measuring devices 26 are also arranged on the implement conveyor 104, where the measuring devices 26 serve to measure the dispensing material using a partial measuring airflow DLTS generated from the measuring airflow DLS. The measuring system 10 of the dispensing machine 100 also comprises a dispensing system 22, through which the dispensing material is transported from one of the storage containers 12, 14 to the measuring devices 26 using the conveyor airflow FLS.

[0034] The distribution system 22 comprises a main distribution unit 24, located below storage containers 12 and 14. The distribution material transported in storage containers 12 and 14 can be fed into the main distribution unit 24 under the influence of gravity. The conveyor airflow (FLS) generated by the conveyor airflow generator 18 is also fed into the main distribution unit 24 via the conveyor air line 28. The main distribution unit 24 is configured to divide the distribution material into several partial conveyor airflows. Petition 870250082310, dated 12 / 09 / 2025, page 20 / 43 12 / 19 (FLTS) generated from the conveyor air.

[0035] When dosing fine seeds, such as rapeseed, there is a risk that, if the conveyor airflow is reduced or absent, the distribution material will flow in the opposite direction to the transport flow towards the conveyor airflow generator 18 due to the dosing airflow. The conveyor airflow generator 18 may be damaged by the backflow of the distribution material. In addition, the distribution material may be unintentionally expelled from the conveyor airflow generator 18 and thus end up in the agricultural field in an uncontrolled manner.To prevent this, the measuring system 10 comprises an anti-reflux device 32 which, when the airflow of the FLS conveyor is reduced or absent, prevents the dispensing material located in the dispensing system 22 from being fed into the conveyor airflow generator 18 of the device assembly 16 by means of one or more dosing airflows flowing in the opposite direction to the conveying direction. Damage to the conveyor airflow generator 18 caused by the reflux of the dispensing material is effectively prevented by the reflux prevention device 32. Unintentional expulsion of the dispensing material from the conveyor airflow generator 18 is also prevented.

[0036] The measuring system 10 also comprises a control device 30. The control device 30 comprises an electronic data processing device. The measurement process performed by the measuring system 10 can be adjusted via the control device 30. The anti-reflux device 32 can be provided as a passive and uncontrollable component or as an actively controllable component. If the device Petition 870250082310, dated 12 / 09 / 2025, page 21 / 43 13 / 19 antireflux device 32 is actively controllable, the air supply line 28 can be blocked and unblocked by means of control commands via the electronic control device 30. If the antireflux device 32 is supplied as a passive and non-controllable component, the open state of the antireflux device 32 may, for example, depend on the direction of flow or inlet.

[0037] Figure 2 shows a measuring system 10 in which a transport airflow FLS is generated by means of a transport airflow generator 18 of a device assembly 16. The transport airflow FLS is fed into the anti-reflux device 32 through line section 28a of the transport air line 28. From the anti-reflux device 32, the transport airflow FLS is fed into the main distribution unit 24 of the distribution system 22 through line section 28b. The transport airflow FLS flows through the anti-reflux device 32 in the transport direction, the anti-reflux device 32 being configured not to exert any blocking effect when the flow occurs in the transport direction.

[0038] The main distribution unit 24 comprises an air inlet opening for the FLS conveyor airflow. In addition, the main distribution unit 24 comprises an upper material inlet opening for the distribution material. Within the main distribution unit 24, the FLS conveyor airflow is divided into a plurality of FLTS conveyor partial airflows, of which, for representational purposes, only one FLTS conveyor partial airflow is shown. The FLTS conveyor partial airflows emerging from the main distribution unit 24 are loaded with the distribution material, resulting in the MS material flows. Petition 870250082310, dated 12 / 09 / 2025, page 22 / 43 14 / 19 The partial airflows from the conveyor loaded with the distribution material are further divided by a dividing device 36, resulting in the partial airflows from the conveyor FLTS1 and FLTS2, as well as the material flows MS1 and MS2. The partial airflow from the conveyor FLTS1 is fed into the measuring device 26a. The partial airflow from the conveyor FLTS2 is fed into the measuring device 26b.

[0039] Measuring devices 26a and 26b are pneumatically operated. For the pneumatic operation of measuring devices 26a and 26b, a measuring airflow generator 20 of the device assembly 16 generates a DLS measuring airflow. The DLS measuring airflow is fed into a measuring airflow splitter 38, which divides the DLS measuring airflow into several partial measuring airflows DLTS. The partial measuring airflows DLTS are then fed into a respective measuring device 26a and 26b, so that the respective measuring device 26a and 26b can be operated by means of the partial measuring airflow DLTS fed to it.

[0040] Dosing devices 26a and 26b can, for example, be overpressure operated separation devices. In this case, the distribution material is seed, which is separated within dosing devices 26a and 26b by overpressure. The partial airflow from the conveyor (FLTS) and the partial airflow from the dosing (DLTS), which are supplied to the respective dosing devices 26a and 26b, are combined in dosing device 26a and 26b and used to guide the measured distribution material towards the agricultural field. The outlet openings of dosing devices 26a and 26b can, for example, be connected to a discharge channel through which the measured distribution material is Petition 870250082310, dated 12 / 09 / 2025, page 23 / 43 15 / 19 unloaded in the direction of the agricultural field.

[0041] If the airflow of the FLS conveyor is reduced or absent, the distribution material can be transported by the partial dosing airflows DLTS in the opposite direction to the transport direction, through the main distribution unit 24, towards the conveyor airflow generator 18. In this case, the anti-reflux device 32, arranged between the line sections 28a and 28b of the conveyor air line 28, prevents the distribution material from being fed into the conveyor airflow generator 18. Damage to the conveyor airflow generator 18 caused by the introduction of the distribution material is thus effectively avoided. Furthermore, the conveyor airflow generator 18 prevents the distribution material from reaching the agricultural field in an uncontrolled manner.

[0042] Figure 3 shows a measuring system 10 in which the anti-reflux device 32 is arranged between the main distribution unit 24 and the measuring devices 26a and 26b. In this configuration, several anti-reflux devices 32 are required to completely prevent the backflow of material in the direction of the conveyor airflow generator 18.

[0043] In the measuring system 10 shown in Fig. 4, the conveyor airflow FLS and the measuring airflow DLS are generated by a flow generator 42 of a device assembly 16. The flow generator 42 generates a main airflow HLS, which is fed via a main air line 34 to a flow splitter 40 of the device assembly 16. The flow splitter 40 divides the main airflow HLS into the measuring airflow DLS and the conveyor airflow FLS.

[0044] In this case, the reflux prevention device 32 Petition 870250082310, dated 12 / 09 / 2025, page 24 / 43 16 / 19 is positioned between the flow divider 40 and the main distribution unit 24 and prevents the distribution material located in the distribution system 22 from entering the flow divider 40 and the flow generator 42.

[0045] In the measuring system 10 shown in Fig. 5, the backflow prevention device 32 is disposed between the line sections 34a, 34b of the main air line 34. The backflow prevention device 32 is therefore located between the flow divider 40 and the flow generator 42 and prevents the distribution material located in the distribution system 22 from being introduced into the flow generator 42. It is also conceivable that, in an embodiment not illustrated, the backflow prevention device 32 is integrated into the flow divider 40, or that a single component performs both functions, or that the backflow prevention device 32 is part of the flow generator 42.

[0046] Fig. 6 shows a conveyor air line 28 leading to a main distribution unit 24. The conveyor air line 28 is equipped with a backflow prevention device 32.

[0047] Figures 7 and 8 show that the anti-reflux device 32 comprises a pipe segment 44, in which two movable shut-off valves 46a and 46b are arranged in the free-flow cross-section of the pipe segment 44. The free-flow cross-section can be closed by means of the movable shut-off valves 46a and 46b through the anti-reflux device 32. In this case, the anti-reflux device 32 is therefore provided as a passive component that cannot be controlled by an electronic control device. The shut-off valves 46a and 46b are pivotable and rotatable in the flow cross-section. Petition 870250082310, dated 12 / 09 / 2025, page 25 / 43 17 / 19

[0048] Fig. 7 shows the anti-reflux device 32 in the open state. In the open state, the pivoting shut-off valves 46a and 46b are aligned parallel to the flow direction.

[0049] In Figure 8, the anti-reflux device 32 is directed through or over the flow in the counter-flow direction, so that the blocking valves 46a and 46b essentially completely block the free-flow cross-section. The stops 48a and 48b for the blocking valves 46a and 46b are located on the pipe segment 44. The stops 48a and 48b ensure that the blocking valves 46a and 46b are maintained in the closed position shown when the flow is directed in the counter-flow direction.

[0050] Blocking valves 46a and 46b are therefore actuated exclusively by the airflow passing through the anti-reflux device 32, depending in particular on the direction of air transport. Alternatively, it would be conceivable that blocking valves 46a and 46b could be actuated by at least one actuator.

[0051] Furthermore, in an embodiment not illustrated, the blocking valves 46a and 46b can be replaced by a different type of blocking device. The blocking device comprises a flow resistance that depends on the direction of transport, so that the blocking device can be actuated, preferably exclusively, by the airflow passing through it. This can be technically implemented by the blocking device having low flow resistance in the flow direction, so that the conveyor airflow can pass at least approximately without loss, while, opposite to the flow direction, the blocking device has high flow resistance, so that an airflow containing the distribution material is impeded. Petition 870250082310, dated 12 / 09 / 2025, page 26 / 43 18 / 19

[0052] The locking device may comprise at least one membrane, partial spherical shell, eccentric flap, lamella or grid. Reference numbers: measuring system, storage container, air flow generator assembly, conveyor air flow generator, measuring system, distribution units, main distribution units, 26a, 26b measuring devices, conveyor air line. 28a, 28b line sections control device backflow prevention device main air line 34a, 34b line sections splitting device air flow divider measuring flow divider flow generator pipe segment 46a, 46b shut-off valves 48a, 48b doorstops 100 dispensing machines 102 main structure Petition 870250082310, dated 12 / 09 / 2025, page 27 / 43 19 / 19 104 implement transporter DLS airflow measurement DLTS partial airflow measurement FLS conveyor airflow FLTS, FLTS1, FLTS2 partial airflow conveyor MS, MS1, MS2 material flows HLS main airflow Petition 870250082310, dated 12 / 09 / 2025, page 28 / 43

Claims

1 / 5 CLAIMS 1. Measuring system (10) for an agricultural distribution machine (100), comprising - a device assembly (16) comprising at least one flow generator (18, 20, 42) for generating a conveyor airflow (FLS) flowing in a conveying direction and a measuring airflow (DLS); - a measuring device (26, 26a, 26b) that is configured to measure the distribution material using a partial measuring airflow (DLTS) generated from the measuring airflow (DLS); and - a distribution system (22) through which the distribution material can be transported from a storage container (12, 14) to the measuring device (26, 26a, 26b) using the conveyor airflow (FLS);characterized by a backflow prevention device (32) whereby, in the event of reduced or absent carrier airflow (FLS), the introduction of distribution material located in the distribution system (22) into the flow generator (18, 20, 42) of the device assembly (16) can be avoided by means of one or more partial metering airflows flowing in the opposite direction to the transport direction.

2. Measuring system (10), according to claim 1, characterized in that the backflow prevention device (32) comprises at least one movable or deformable blocking valve (46a, 46b) by means of which a free flow cross-section through the backflow prevention device (32) can be partially or completely closed.

3. Measurement system (10), according to claim 1 Petition 870250082310, dated 12 / 09 / 2025, page 29 / 43 2 / 5 or 2, characterized in that the backflow prevention device (32) is configured to be actuated by the airflow passing through the backflow prevention device (32).

4. Measuring system (10), according to any one of claims 1 to 3, characterized in that the backflow prevention device (32) comprises an actuator that is actively controllable for opening and / or closing the backflow prevention device (32).

5. Measuring system (10), according to any one of claims 1 to 4, characterized in that the distribution system (22) comprises a main distribution unit (24) into which the distribution material and the conveyor airflow (FLS) can be introduced and which is configured to divide the distribution material into several partial conveyor airflows (FLTS, FLTS1, FLTS2) generated from the conveyor air.

6. Measurement system (10), according to claim 5, characterized in that the device assembly (16) comprises a conveyor air flow generator (18) for generating the conveyor air flow (FLS) and a measuring air flow generator (20) for generating the measuring air flow (DLS), wherein the backflow prevention device (32) is disposed between the conveyor air flow generator (18) of the device assembly (16) and the main distribution unit (24) of the distribution system (22).

7. Measuring system (10), according to claim 5, characterized in that the backflow prevention device (32) is disposed between the main distribution unit (24) of the distribution system (22) and the measuring device Petition 870250082310, dated 12 / 09 / 2025, page 30 / 43 3 / 5 (26, 26a, 26b).

8. Measuring system (10), according to claim 5, characterized in that the device assembly (16) comprises a flow generator (42) for generating a main airflow (HLS) and a flow divider (40) for generating the carrier airflow (FLS) and the measuring airflow (DLS) from the main airflow (HLS).

9. Measurement system (10), according to claim 8, characterized in that the backflow prevention device (32) is located between the flow divider (40) of the device assembly (16) and the main distribution unit (24) of the distribution system (22) or between the flow generator (42) of the device assembly (16) and the flow divider (40) of the device assembly (16).

10. Measuring system (10), according to any one of claims 1 to 9, characterized in that the measuring device (26, 26a, 26b) is provided as an overpressure operated measuring device (26, 26a, 26b).

11. Method for dosing distribution material by means of a measuring system (10) of an agricultural distribution machine (100), in particular by means of a measuring system (10), as defined in any of claims 1 to 10, comprising the steps: - generating a conveying airflow (FLS) flowing in the conveying direction and a measuring airflow (DLS) by means of a device assembly (16) of the measuring system (10) comprising at least one flow generator (18, 20, 42); - measuring the distribution material by means of a measuring device (26, 26a, 26b) of the measuring system (10) using a Petition 870250082310, dated 12 / 09 / 2025, p.31 / 43 4 / 5 partial measuring airflow (DLTS) generated from the measuring airflow (DLS); and - transporting distribution material from a storage container (12, 14) to the measuring device (26, 26a, 26b) by means of a distribution system (22) of the measuring system (10) using the conveyor airflow (FLS); characterized in that it has the step of: - preventing the distribution material located in the distribution system (22) from being introduced into the flow generator (18, 20, 42) of the device assembly (16) when the conveyor airflow (FLS) is reduced or absent by means of one or more partial measuring airflows flowing in the opposite direction to the transport direction by means of a backflow prevention device (32) of the measuring system (10).

12. Method according to claim 11, characterized in that - the backflow prevention device (32) is actuated by the airflow flowing through the backflow prevention device (32); and / or - an actuator of the backflow prevention device (32) is actively controlled to open and / or close the backflow prevention device (32).

13. Method according to claim 11 or 12, characterized in that the distribution material and the conveyor airflow (FLS) are introduced into a main distribution unit (24) of the distribution system (22), which divides the distribution material into several partial conveyor airflows (FLTS, FLTS1, FLTS2) generated from the conveyor airflow (FLS), Petition 870250082310, dated 12 / 09 / 2025, page 32 / 43 5 / 5 wherein a backflow of the distribution material is prevented by means of the backflow prevention device (32) - between a conveyor airflow generator (18) of the device assembly (16) and the main distribution unit (24) of the distribution system (22); or - between the main distribution unit (24) of the distribution system (22) and the measuring device (26, 26a, 26b).

14. Method according to claim 11 or 12, characterized in that the device assembly (16) comprises a flow generator (42) for generating a main airflow (HLS), and the conveyor airflow (FLS) and the metering airflow (DLS) are generated from the main airflow (HLS) by means of a flow divider (40), wherein a return flow of the dispensing material is prevented by means of the backflow prevention device (32) - between the flow divider (40) of the device assembly (16) and the main dispensing unit (24) of the dispensing system (22); or - between the flow generator (42) of the device assembly (16) and the flow divider (40) of the device assembly (16). Petition 870250082310, dated 12 / 09 / 2025, pp. 33 / 43

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