SEEDING MACHINE AND METHOD FOR SINGLING AND SPREADING GRANULES

Abstract

The invention relates to a sowing machine (1, 31) and a method for separating and distributing granular material (2), such as seeds or similar, wherein the material is supplied from a central container (12) to metering devices (3) via respective conveying channels (11) assigned to same, by means of conveying air flows (10), and discharged from same. Resulting waste air flows (14) are supplied to the respective associated metering devices via waste air channels (15) and said metering devices are thereby applied with overpressure. In addition, the metering chambers are applied with overpressure via said respective assigned supply channels (8) by means of supply air flows (7). The material is separated in the metering chambers by means of separating discs (5). Given that the supply air flows and the waste air flows are physically separately introduced into the metering chambers, the required pressure level in the discharging devices (13) generating the waste air flows can be reduced and thereby also the pressure level in the granular material delivered to the metering devices from the discharging devices. This improves the separation quality of the metering devices.

Description

Seed drill and method for singling and spreading granular material The invention relates to a seed drill for singling and spreading granular material, such as seeds, fertilizer or pesticide, according to the preamble of claim 1, and to a corresponding method according to the preamble of claim 9. A seed drill and a method of this type are known from EP 2 854 500 B1. According to this patent, granular material is fed from a central container to several metering devices via conveying channels, each with its own associated conveying channel, by means of conveying air streams. The granular material is separated from the conveying air streams in separating devices and fed to the respective metering devices. These devices are also supplied with supply air streams via supply channels, generated, for example, by a separate blower, which serve to pressurize the metering devices. This pressure is required to cover the singulation discs within them with the granular material in a controlled manner, and the material is then dispensed in this singulated form via a seed channel. Exhaust air streams resulting from the separation of material in the separating devices are routed via exhaust air ducts into the individual supply ducts and then fed together with the supply air streams to their respective metering devices. To effectively mix the exhaust air with the supply air streams in the supply ducts, the combined air streams should have comparable pressure levels. However, pressure losses occur in the supply air stream due to its high volume, so that a higher pressure inevitably prevails in the supply duct area than in the area of ​​the metering device in order to achieve the required pressure there. Due to this pressure difference and the conditions for introducing the exhaust air into the supply air streams, comparatively high pressure levels also prevail in the area of ​​the separated material, in the downstream seed duct, and in the associated metering chamber. It has now surprisingly emerged that these high pressure levels hinder the usual stirring of the granular material in the inlet area of ​​the dosing device and can lead to incorrect placement of the granular material on the singulation disc. This impairs the singulation quality. Therefore, there is a need for improved seed drills and methods for singling and spreading granular material, such as seeds, fertilizers, pesticides, or the like. The problem is solved with a seed drill according to claim 1 and a method according to claim 9. Accordingly, the seed drill comprises at least two metering devices with metering chambers and singulation discs arranged therein for singulating the granular material, as well as at least one blower for generating supply air streams to pressurize the individual metering chambers via their respective supply channels, and for generating conveying air streams to supply the granular material from a central container to the individual metering devices via their respective conveying channels. Furthermore, the seed drill comprises separator devices, which are positioned upstream of the metering devices in the area of ​​the metering devices, in order to separate the material supplied in the conveying channels from the respective conveying air stream and to supply the resulting exhaust air streams via exhaust air channels to the respective metering devices for their pressurization. According to the invention, the supply channels and the exhaust air channels open separately into the dosing chambers that are jointly assigned to them. During operation, the pressure in the metering chambers is inevitably lower than in the associated supply channels. Since the exhaust air ducts open directly into the metering chambers, unlike the conventional system where exhaust air ducts open into the supply channels upstream of the metering chambers, the exhaust air ducts can be maintained at a lower pressure level. This reduces the pressure in the associated separator compared to conventional seed drills with seed feeders. Consequently, the pressure level in the seed channel following the separator can also be reduced. This allows the incoming granular material to be stirred more thoroughly and prevents excessive pressure of the granular material on the singulation disc. For example, it prevents the granular material from adhering too strongly to areas of the singulation disc that are not intended for use, thus preventing the material from being fed into the designated recesses. Furthermore, it simplifies the process of wiping the singulation disc. This improves the overall coverage of the singulation discs with the granular material and consequently the singulation quality of the dosing devices. Preferably, the exhaust air ducts open into sections of the metering chambers where a conveying path for the singulation discs extends upwards. Typically, the granular material advancing from above through the seed channel collects in a lower section of the singulation disc. The conveying path then continues upwards along a circular path on the singulation disc, where the granular material is picked up. Also located in the ascending section of the conveying path is a scraper device for removing excess granular material from the singulation disc. By selectively directing the exhaust air streams onto the upward-running section of the conveying path, the loading of the singulation disc with granular material and the scraping of the singulation disc can be favorably influenced. Preferably, scraper elements for removing material from the singulation discs are arranged in the metering chambers, with the exhaust air ducts opening upstream of the scraper elements and / or in their vicinity, relative to the conveying path of the singulation discs. This allows, for example, granular material that has remained on a holder for adjusting the scrapers located on the scraping device to be blown off. Preferably, the seed drill further comprises at least one air distributor arranged downstream of the blower for adjusting the conveying air flows and the supply air flows such that the exhaust air flow supplied to the individual metering devices is weaker than the supplied supply air flow, in particular at most half as strong. For example, the volume flow of the supply air flow is then two to five times greater than the simultaneously supplied volume flow of the exhaust air flow. This allows the overpressure level required for singulation in the metering chamber to be produced predominantly with the supply airflow, and the exhaust airflow to be used for targeted supplementation of the overpressure in an area of ​​the scraping device and / or downstream of it. An air distributor, in conjunction with a blower whose conveying capacity can be adjusted, is suitable both for setting the required conveying airflow for the respective feeding of the granular material and for using the supply airflow to create a To establish a suitable pressure level within the metering chamber, separate blowers for generating the conveying and supply air flows are then unnecessary. In a further advantageous embodiment of the seed drill, it comprises at least one first blower for generating the conveying air streams and at least one independently adjustable second blower for generating the supply air streams. The first and second blowers are designed and controllable such that the exhaust air stream supplied to the individual metering devices, particularly with regard to the volume flow, is weaker than the supplied air stream, also particularly with regard to the volume flow, preferably at most half as strong. In particular, the volume flow of the supply air stream is then two to five times greater than the volume flow of the exhaust air stream. The conveying air streams and the supply air streams can then be controlled relatively flexibly and easily independently of each other. In a further advantageous embodiment, the seed drill also includes valves assigned to the exhaust air ducts and / or supply air ducts for adjustable attenuation of the exhaust air flows and / or supply air flows such that a mixing ratio can be set between the exhaust air flow and the supply air flow supplied to the individual metering devices. In particular, the exhaust air flow is weaker than the supplied supply air flow, and especially at most half as strong. In particular, the volume flow of the supply air flow is then two to five times greater than the volume flow of the exhaust air flow. This allows the volume flow of the exhaust air stream to be reduced independently of the pressure level prevailing at the inlet of the associated separator. This is particularly advantageous in conjunction with a central air distributor or separate fans, as described above. Preferably, the seed drill further comprises at least one measuring device for measuring a volume flow rate and / or an overpressure in at least one of the separating devices and / or exhaust air ducts. On this basis, the volume flow rates of the exhaust air can be adjusted to setpoint values ​​even under changing operating conditions, in order to ensure a targeted and reproducible feed of exhaust air streams into the metering devices. The described method is used for singulating and dispensing granular material, such as seeds, fertilizer, pesticides, or the like. For this purpose, the granular material is conveyed from a central container to metering devices via metering channels using compressed air streams. The material fed into the respective conveying channels is separated from the material in the respective container. The conveying air stream is separated, and the resulting exhaust air streams are fed via exhaust air ducts to the respective metering devices, thereby pressurizing them. The metering chambers are further pressurized via supply air streams through their respective supply ducts. The granular material is singulated in the metering chambers by means of singulation discs. According to the invention, the supply air streams and the exhaust air streams are fed into the metering chambers separately from each other. This allows the advantages described for the seed drill according to the invention to be achieved. Preferably, the exhaust air streams, relative to the conveying flow of the granular material at the singulation discs, are fed into the metering chambers upstream of the supply air streams. This allows a collection area for the granular material in the metering chamber to be selectively exposed to the exhaust air stream, for example to support the stirring of the granular material and / or to facilitate the loading and scraping of the singulation disc. Preferably, the exhaust air streams are directed towards the scraper devices for the singulation discs located in the metering chambers and / or upstream sections of the metering chambers. This allows, for example, granular material that has remained on a holder for adjusting the scrapers located on the scraper device to be blown off. Preferably, the supplied airflows are stronger than the supplied exhaust airflows, in particular at least twice as strong. It is especially advantageous if the supply airflows have a volume flow rate two to five times greater than the exhaust airflows. Preferably, the pressure levels prevailing in the exhaust air ducts during singulation are lower than in the supply ducts, particularly in the sections immediately before feeding into the metering devices. This allows a comparatively large flow rate and thus a comparatively large mass flow of the granular material to be supplied to the separating device and the metering device without hindering the coating of the singulation discs with the granular material, especially in the area of ​​an agitator present in the metering devices. Preferably, the supply airflows and the conveying airflows are generated in separate blowers and / or by central airflow division downstream of at least one common blower. This allows the conveying airflows and the supply airflows to be flexibly and automatically adjusted as needed during the ongoing operation of the seed drill by means of a control system. Preferred embodiments of the invention are illustrated in the drawings. They show: Fig. 1 shows a schematic representation of the seed drill with the described airflow guidance; Fig. 2 shows a schematic representation of a metering chamber with the feed of the supply airflow and the airflow; Fig. 3 shows the seed drill according to Fig. 1 with an alternative central airflow direction. As can be seen in Fig. 1, the seed drill 1 for singulating and spreading granular material 2, such as seed, fertilizer, pesticide or the like, comprises several metering devices 3 with metering chambers 4 and singulation discs 5 arranged therein (indicated by the direction of rotation arrow) for singulating the granular material 2. Furthermore, the seed drill 1 preferably comprises a first blower 6 for generating supply air flows 7 for pressurizing the individual metering chambers 4 via supply channels 8 assigned to each of them. Furthermore, the seed drill 1 preferably comprises a second blower 9 for generating conveying air streams 10 for supplying the granular material 2 to the individual metering devices 3 via conveying channels 11 assigned to each of these. For this purpose, the granular material 2 is held in a central container 12 at the seed drill 1 in a known manner. Upstream of the mass flow, separating devices 13 are arranged on each of the metering devices 3, in which the granular material 2 fed in the conveying channels 11 is separated from the conveying air stream 10 loaded with it. The separation process results in essentially unloaded exhaust air streams 14, which are fed via exhaust air ducts 15 to the respective metering devices 3 for pressurization. The supply channels 8 and the exhaust air channels 15 open into the respective dosing chambers 4 in separate locations and preferably also into different areas of the dosing chambers 4. Fig. 2 schematically shows one of the metering chambers 4 with a rotatable singulation disc 5 within it. Also schematically shown is a seed channel 16 through which the granular material 2 advances from the separator 13 above into the metering chamber 4. The granular material 2 can accumulate in a lower collection area 17 within the metering chamber 4 for subsequent singulation. Only partially shown are the fully distributed recesses 5a in the singulation disc 5 for receiving / singling the granular material 2, as well as a scraping device 18 for scraping the singulation disc 5. For the sake of completeness, a discharge channel 19 for the singulated granular material 2 is also indicated, see also Fig. 1. Starting from the collection area 17, the recesses 5a define a conveying path 20 of the singulation disc 5 (indicated by an arrow). The conveying path 20 runs essentially from the collection area 17 to a discharge point 21, where the singulated granular material 2 leaves the recesses 5a and is discharged by the metering device 3 through the discharge channel 19. For illustrative purposes, a first feed opening 15a with respect to the conveying path 20, at which the exhaust air duct 15 opens into the dosing chamber 4, and a second feed opening 8a with respect to the conveying path 20, at which the supply duct 8 opens into the dosing chamber 4 are also shown. Accordingly, both the first feed opening 15a (of the exhaust air duct 15) and the scraping device 18 are arranged in an area of ​​the metering chamber 4 in which the conveying path 20 runs upwards, i.e. in the direction of the seed channel 16. The second feed opening 8a (of the supply channel 8) is preferably arranged downstream of the first feed opening 15a in a region of the metering chamber 4, such that the conveying path 20 of the singulation disc 5 runs downwards again. As a temporary measure, the metering chamber 4 in Fig. 2 is divided horizontally / vertically into quadrants I to IV with respect to the axis of rotation of the 5b of the junction disc 5. As can be seen in this respect, the first feed opening 15a is preferably located in the quadrant I to IV, with respect to the feed- The first feed opening 15a is located in the area of ​​the second quadrant II, the scraping device 18 in the second quadrant II, and the second feed opening 8a in the third quadrant III. Alternatively, the first feed opening 15a could also be arranged in the area of ​​the second quadrant II or at its transition to the first quadrant I. The separate feeding of the exhaust air stream 14 through the first feed opening 15a in the rising part of the conveying path 20, i.e. in the first quadrant I and / or second quadrant II, enables a particularly reliable covering of the singulation disc 5 with the granular material 2 and / or a targeted blowing on the scraper device 18, for example to remove residues of the granular material 2 from holders for scraper elements or the like located thereon. In contrast, the separate feeding of the supply airflow 7 through the downstream feed opening 8a, i.e., in particular in the third quadrant III, enables a separately adjustable basic supply of overpressure to the dosing chamber 4 for singulating the granular material 2 at the singulation disc 5. In this context, the direct flow-related connection between the separating device 13 and the first feed opening 15a via the exhaust air duct 15 is particularly advantageous, so that a comparatively low pressure level can be set in both this and in the separating device 13, without thereby restricting the mass flow of the granular material 2 that can be supplied with the respective conveying air flow 10 in an unfavorable way, for which a certain pressure difference between the blower 9 generating the conveying air flow 10 and the separating device 13 must not be undercut. The pressure level in the separating device 13 can therefore be kept as low as in the dosing device 3. This promotes proper loading of the singulation disc 5 with the granular material 2 and, in particular, effective stirring of the granular material 2 by means of a stirrer 22, which is only schematically indicated in Fig. 2. In addition to improving the singulation quality, this also allows the individual compressed air streams to be generated more efficiently than with the known merging of the supply air streams and exhaust air streams upstream of the metering devices. Figure 3 shows the seed drill 31 as an example of an alternative embodiment, which differs essentially only in its central air supply from the seed drill 1 described above. Accordingly, the seed drill 31 does not require separate blowers for the supply air streams 7 and the conveying air streams 10. Instead, for example, only the first blower 6 or the second blower 9 may be present, along with a central air distributor 32 arranged downstream of it, which divides a total air stream 33 (here, by way of example, generated by the blower 6) into the supply air streams 7 and the conveying air streams 10. For this purpose, preferably both the blower 6 and the central air distributor 32 can be controlled / regulated via an exemplary control 34, so that on the one hand the total airflow 33 can be set and on the other hand its division into the supply airflows 7 and the conveying airflows 10. Optionally, each of the exhaust air ducts 15 and the supply air ducts 8 could also be equipped with a valve 35 to reduce the exhaust air flow 14 or supply air flow 7. This would allow the respective exhaust air flow 14 and / or supply air flow 7 to be selectively reduced independently of the pressure level prevailing at the inlet of the associated separator device 13. Thus, a mixing ratio of the exhaust air flow 14 and supply air flow 7 supplied by each of the individual metering devices 3 can be set. Schematically indicated are also measuring devices 36, 37 for measuring an overpressure in at least one of the separating devices 13 and / or for measuring a volume flow in at least one of the exhaust air ducts 15. This would allow the exhaust air flows 14 to be controlled / regulated in a targeted manner under different operating conditions in the area of ​​the separating devices 13. It goes without saying that the control system 34, the valves 35 and / or the measuring devices 36, 37, which are shown only as examples in Fig. 3, are also present in the seed drill 1 described above, in order to control / regulate, for example, the blowers 6, 9 and thus the separately generated supply air streams 7, conveying air streams 10 and finally also the exhaust air streams 14. During operation of the seed drill 1, 31, the supply air streams 7 fed into the metering chambers 4 are preferably stronger than the exhaust air streams 14 fed in simultaneously. It has proven advantageous to use at least one of the blowers 6, 9 and / or adjust the central air distributor 32 and / or the valves 35 such that the supply air flows 7 are each at least twice as strong as the associated exhaust air flows 14. A ratio of 1:2 to 1:5 of the respective exhaust air flow 14 to the respective supply air flow 7 fed into the same metering device 3 has proven to be particularly practical. This ratio preferably refers to the ratio of the respective volume flows. This allows the singulation quality of the granular material 2 finally discharged by the seed drill 1, 31, i.e. in the individual discharge channels 19, to be optimized relatively flexibly, for example with regard to different granular materials 2 and / or operating conditions.

Claims

Claims 1. Seed drill (1, 31) for singling and spreading granular material (2) such as seed, fertilizer or pesticide, comprising: - Metering devices (3) with metering chambers (4) and singulation discs (5) arranged therein for singulating the granular material; - at least one blower (6, 9) for generating supply air flows (7) for pressurizing the individual metering chambers (3) via their respective supply channels (8) and for generating conveying air flows (10) for feeding the granular material from a central container (12) to the individual metering devices via their respective conveying channels (11); and - Separation devices (13) which are positioned upstream of the metering devices in the area of ​​the metering devices in order to separate the granular material supplied in the conveying channels from the respective conveying air stream and to provide the resulting exhaust air streams (14) via exhaust air channels (15) to the respective metering devices for pressurization, characterized in that the supply channels and the exhaust air channels open separately into the metering chambers jointly assigned to them.

2. Seed drill according to claim 1, wherein the exhaust air channels (15), with respect to a conveying path (20) of the singulation discs (5), open upstream of the supply channels (8) into the metering chambers (4).

3. Seed drill according to claim 1 or 2, wherein the exhaust air channels (15) open into partial areas of the metering chambers (4) in which a conveying path (20) of the singulation discs (5) runs upwards.

4. Seed drill according to claim 1, 2 or 3, wherein in the metering chambers (4) stripping devices (18) for stripping the singulation discs (5) are arranged and the exhaust air channels (15), with respect to a conveying path (20) of the singulation discs, open upstream of the stripping devices and / or into their area.

5. Seed drill according to one of the preceding claims, further comprising at least one air distributor (32) arranged downstream of the blower (6, 9) for adjusting the conveying air flows (10) and the supply air flows (7) such that the The exhaust air flow (14) supplied to each of the individual metering devices (3) is weaker than the supply air flow (7) supplied to each, in particular at most half as strong.

6. Seed drill according to at least one of the preceding claims, comprising at least a first blower (6) for generating the supply air streams (7) and at least one independently adjustable second blower (9) for generating the conveying air streams (10), wherein the first and second blowers are designed and controllable in such a way that the exhaust air stream (14) supplied to each of the individual metering devices (3) is weaker than the respective supply air stream (7), in particular at most half as strong.

7. Seed drill according to one of the preceding claims, further comprising valves (35) associated with the exhaust air channels (15) and / or supply channels (8) for adjustable attenuation of the exhaust air flows (14) and / or supply air flows (7) such that a mixing ratio of the exhaust air flow (14) and supply air flow (7) supplied to each of the individual metering devices (3) can be adjusted.

8. Seed drill according to at least one of the preceding claims, further comprising at least one measuring device (36, 37) for measuring a volume flow and / or an overpressure in at least one of the separating devices (13) and / or exhaust air channels (14).

9. Method for singling and dispensing granular material (2), such as seeds, fertilizer or pesticide, wherein the granular material is fed from a central container (12) to metering devices (3) via conveying channels (11) assigned to each of these by means of conveying air streams (10), wherein the granular material fed in the conveying channels is separated from the respective conveying air stream and the resulting exhaust air streams (14) are fed via exhaust air channels (15) to the respective metering devices and are thereby pressurized, wherein the metering devices are pressurized via supply channels (8) assigned to them by means of supply air streams (7), and wherein the granular material is singulated in the metering devices by means of singling discs (5), characterized in that the supply air streams and the exhaust air streams are fed into the metering devices separately from each other.

10. Method according to claim 9, wherein the exhaust air streams (14), with respect to a conveying stream (20) of the granular material (2), are fed into the singulation discs (5) upstream of the supply air streams (7).

11. Method according to claim 9 or 10, wherein the exhaust air streams (14) are directed towards scraper devices (18) for the singulation discs (5) located in the metering devices (3) and / or upstream sub-areas of the metering devices.

12. Method according to one of claims 9 to 11, wherein the supplied airflows (7) are stronger than the supplied exhaust airflows (14), in particular at least twice as strong, and in particular have a volume flow rate two to five times greater.

13. Method according to one of claims 9 to 12, wherein during the uniting process the prevailing pressure levels in the exhaust air ducts (15) are lower than in the supply ducts (7), in particular in associated sections immediately before feeding into the metering devices (3).

14. Method according to any one of claims 9 to 13, wherein the supply air streams (7) and the conveying air streams (10) are generated by means of separate blowers (6, 9) and / or by central air stream division downstream of at least one blower to generate a common total air stream (33).