Distributing tower of an agricultural distributing machine and method for series cut-off on such a distributing tower

Abstract

A distribution tower of an agricultural distribution machine for spreading granular material comprises a riser pipe supplying a flow of distribution goods to a ring-shaped distributor head for dividing the flow into a multitude of flows of distribution goods along the circumference of the distributor head. At least one of the outflows has a shut-off device. The shut-off device has a track switch operable to selectively guide the flow of distribution goods toward a seed tube or toward a return section. A return device connects to and surrounds the riser pipe. Openings in the riser pipe serve to receive the returned distribution goods. The return section, as well as the seed tube connection, are permanently, pneumatically connected. A method is also provided where it is possible to shut off an optional number of outflows without any resulting major change of the lateral distribution.

Claims

1. A distribution tower for an agricultural distribution machine for spreading granular distribution goods, the distribution tower comprising a riser pipe- for supplying an air volume flow of distribution goods to a distributor head connected to the riser pipe at an upper end thereof, with the distributor head dividing the air volume flow of granular distribution goods into a multitude of partial air volume flows of granular distribution goods corresponding to a number of outflows distributed along a circumference of the distributor head, wherein at least one of the outflows has a shut-off device associated therewith; wherein the shut-off device has a track switch by means of which the particular partial air volume flow of granular distribution goods can be guided toward a seed tube connection associated with the shut-off device or toward a return section associated with the shut-off device; wherein a return device connects to the return section, with the return device surrounding the riser pipe or being part of the riser pipe; and wherein the riser pipe has openings extending therethrough, in flow communication with the return device, the openings serving for receiving the granular distribution goods returned through the return device, wherein the riser pipe, the return device, and the return section, as well as the seed tube connection are permanently pneumatically connected, independently of the particular position of the track switch, wherein the return section is connected to the seed tube connection by a bypass including a separator section extending vertically from an opening between the bypass and the return channel.

2. The distribution tower as recited in claim 1 wherein the return section has a return connection and a return opening and a funnel-shaped member.

3. The distribution tower as recited in claim 1 wherein a collecting piece and a return tube and a funnel-shaped member connect to the return section and form a return device and lead into such return device.

4. The distribution tower as recited in claim 1 wherein the connection between the return section and the seed tube connection is achieved by means of a bypass.

5. The distribution tower as recited in claim 4 wherein slits and/or holes and/or openings serving as the bypass are associated with the track switch.

6. The distribution tower as recited in claim 4 wherein slits and/or holes and/or openings serving as the bypass are associated with a partition wall between the return section and the seed tube connection.

7. The distribution tower as recited in claim 4 wherein the bypass is designed as a pipeline or tubing, or in that the bypass is integrated as an air channel into the shut-off device or into the distributor head.

8. The distribution tower as recited in claim 1, wherein a pressure level P1 is applied in the return device, as well as a pressure level P2 and P3 being applied in the return section and respectively in the bypass, wherein P1 is less than or equal to P2 and P3.

9. The distribution tower as recited in claim 1 wherein the riser pipe has a section of reduced cross-section forming at least one nozzle and the openings extending through the riser pipe extend through the nozzle.

10. The distribution tower as recited in claim 1 wherein the shut-off device comprises at least of a flange surface, a return section, which preferably comprises of a return connection and a return channel extending between the flange surface and the return connection, a seed tube connection, and a seed channel-extending between the flange surface and the seed tube connection, and wherein a bypass extends between the return connection and the seed tube connection.

11. The distribution tower as in claim 1 wherein the air volume flow flowing from the return channel into the separator section undergoes a change in direction greater than 135.

12. The distribution tower as recited in claim 1 wherein the bypass has a flow resistance that is largely identical to the flow resistance prevailing at the seed tube connection when the track switch is in an open position.

13. The distribution tower as recited in claim 1 wherein sensors are associated with the shut-off device with the number or the amount of passing grains of the distribution goods being determined by means of said sensors.

14. The distribution tower as recited in claim 13 wherein the position of the track switch is modified based on the number and/or on the amount of passing grains of the distribution goods.

15. The distribution tower as recited in claim 1 wherein the shut-off device and the return section are integrated into the distributor head.

16. An improved shut-off device for a distribution tower of an agricultural distribution machine for spreading granular distribution goods with a riser pipe for supplying the distribution goods to a distributor head connected at the top to the riser pipe, with the distributor head serving for dividing the air volume flow of granular distribution goods into a multitude of partial air volume flows of granular distribution goods corresponding to a number of outflows distributed along a circumference of the distributor head, wherein each of said outflows has one of the shut-off devices associated therewith, wherein each shut-off device has a track switch through which an air volume flow of granular distribution goods can be guided toward a seed tube connection associated with the shut-off device or toward a return section associated with the shut-off device; wherein a return device connects to the return section; wherein the return device surrounds the riser pipe or is formed as part of said riser pipe; and wherein the riser pipe has openings extending therethrough, in flow communication with the return device, the openings serving for receiving the granular distribution goods returned through the return device, wherein, in the improved shut-off device, the riser pipe, the return device, and the return section, as well as the seed tube connection are permanently pneumatically connected, independently of the position of the track switch, by a bypass pneumatically connecting the return section to the seed tube connection, the bypass including a separator section extending vertically from an opening between the bypass and the return section, whereby a pressure level P1 results in the return device, and a pressure level P2 and P3 result in the return section and in the bypass respectively, wherein P1 is less than or equal to P2 and P3 respectively.

17. The improved shut-off device as in claim 16 wherein sensors are associated with the shut-off device or with the seed tube or with the return section, with the number or the amount of passing grains of distribution goods being determined by means of said sensors.

18. The improved shut-off device as in claim 16 wherein the position of the track switch is modified based on the number or the amount of passing grains of the distribution goods.

19. The improved shut-off device as in claim 16 wherein the track switch is pivoted by means of an electric or pneumatic or hydraulic actuator.

20. The improved shut-off device as in claim 16 wherein the control of the track switch is carried out by means of a computer unit, with the computer unit transmitting signals by manual input or based on GPS data to the actuator.

21. A distribution tower for an agricultural distribution machine for spreading granular distribution goods, the distribution tower comprising a riser pipe for supplying an air volume flow of granular distribution goods to a distributor head connected to the riser pipe with the distributor head dividing the air volume flow of granular distribution goods into a plurality of partial air volume flows of granular distribution goods corresponding to a number of outflows distributed along a circumference of the distributor head, wherein at least one of the outflows has a shut-off device connected thereto; wherein the shut-off device includes a seed channel, a bypass channel and a return channel formed therein with the seed channel connected between an inlet passage and a seed channel outlet, the return channel connected between said inlet passage and a return channel outlet, and the bypass channel connected between the seed channel and the return channel; a track switch is pivotably mounted within the shut-off device and pivotable between an open position in which the track switch closes off the return channel from the inlet passage while leaving the seed channel open to the inlet passage such that a partial air volume flow of granular distribution goods entering the inlet passage is guided from the inlet passage through the seed channel toward a seed tube connection of the shut-off device and a closed position in which the track switch closes off the seed channel from the inlet passage while leaving the return channel open to the inlet passage such that the partial air volume flow of granular distribution goods entering the inlet passage is guided from the inlet passage through the return channel toward a return connection of the shut-off device to which a return line is connected for delivering the partial air volume flow of granular distribution goods to a return device surrounding the riser pipe and wherein the riser pipe has openings extending therethrough, in flow communication with the return device through which the granular distribution goods in the partial air volume flow from the return channel re-enter the riser pipe, wherein the riser pipe, the return device, the return channel and the seed channel are pneumatically connected through the bypass channel independent of the position of the track switch.

22. The distribution tower as in claim 21 wherein the track switch is pivotally connected to a divider separating the seed channel and the return channel from the bypass channel.

23. The distribution tower as in claim 21 wherein a first portion of the bypass channel extends parallel to the return channel.

24. The distribution tower as in claim 21 wherein a first portion of the bypass channel extends parallel to the return channel and a second portion of the bypass channel extends parallel to the seed channel.

25. The distribution tower as in claim 21 wherein the bypass channel opens into the return channel at a bypass return channel opening and into the seed channel at a bypass seed channel opening, and the bypass channel includes a separating section extending vertically from the bypass return channel opening.

26. The distribution tower as in claim 25 wherein a flow path of a portion of the air volume flow flowing from the inlet passage through the return channel and into the separating section of the bypass channel undergoes a change in direction of greater than 90 relative to the flow path of the air volume flow flowing through the return channel.

27. The distribution tower as in claim 25 wherein a flow path of a portion of the air volume flow flowing from the inlet passage through the return channel and into the separating section of the bypass channel undergoes a change in direction of greater than 135 relative to the flow path of the air volume flow flowing through the return channel.

28. The distribution tower as in claim 25 wherein a flow path of a portion of the air volume flow flowing from the inlet passage through the return channel and into the separating section of the bypass channel undergoes a change in direction of approximately 180 relative to the flow path of the air volume flow flowing through the return channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic view of an agricultural distribution machine.

(2) FIG. 2A shows a perspective view of a distribution tower.

(3) FIGS. 2B and 2C show a seed distribution tower with different positions of a track switch in two cross-sectional side views.

(4) FIG. 3A shows a perspective view of a further embodiment variant distribution tower.

(5) FIG. 3B shows a further embodiment variant of a distribution tower with different positions of a track switch in a cross-sectional side view.

(6) FIGS. 4A and 4B show an exemplary embodiment of a shut-off unit with different positions of a track switch.

(7) FIG. 5 shows a further embodiment variant of a distribution tower without a track switch in a cross-sectional side view.

DETAILED DESCRIPTION OF THE INVENTION

(8) The same or equivalent elements of the invention are each designated by the same reference characters in the FIGS. 1 to 5. Furthermore and for the sake of clarity, only the reference characters relevant for describing the individual figures are provided. It should be understood that the detailed description and specific examples of the embodiments of the apparatus or of the method according to the invention are intended for purposes of illustration only and are not intended to limit the scope of the invention.

(9) FIG. 1 shows a distribution tower 10 that is built into an agricultural machine 12 in a schematic view. Said machine is a sowing machine such as is used for distributing granular-type distribution goods, like seeds, fertilizer, or the like. The machine has a storage hopper 14 for storing and supplying the particular distribution goods to be spread. The storage hopper 14 is designed to be funnel-shaped, with a metering device 16 being associated with it at the lowest position of the storage hopper 14. The particular distribution goods to be spread are evenly metered by means of the metering device 16 in a desired amount into a duct system 18 that has an air volume flow guided inside it. The air volume flow is generated by means of an air blower 20 that is likewise associated with the duct system 18. An air volume flow of distribution goods results from the admixture of distribution goods to the air volume flow. The distribution goods are conveyed by means of the air volume flow via the duct system 18 toward the distribution tower 10. In this context, the distribution tower 10 first has a vertically running riser pipe 22, to the top end of which a distributor head 24 connects, which distributor head 24 has a plurality of outflows 26 disposed evenly around its circumference. In the distributor head 24, the air volume flow of distribution goods first undergoes a change of direction from a movement along the riser pipe 22 to a movement toward the outflows 26, in which context the individual, central air volume flow of distribution goods is divided into a plurality of partial air volume flows of distribution goods corresponding in number to the number of outflows. A shut-off unit 28 that is schematically illustrated here with a track switch 30 that is not illustrated here is associated with at least one of the outflows 26. In each case at least one seed tube 32 is disposed at the outflows or rows 26, as the case may be, by means of which seed tube 32, the distribution goods are transported from the distributor head 24 toward spreading devices (not illustrated here) that are being guided near ground level or in the soil, such as disk coulters, tine coulters, or the like.

(10) FIGS. 2A, 2B, and 2C show an embodiment variant of a distribution tower 10 according to the invention in various views, with FIG. 2A illustrating the distribution tower 10 in a perspective view and the FIGS. 2B and 2C illustrating it in a cross-sectional side view. The distribution tower 10 essentially comprises of a riser pipe 22, to the top end of which a distributor head 24 connects. A plurality of outflows or rows 26, as the case may be, are disposed evenly spaced along the circumference of the distributor head 24. The distribution tower 10 first has a transition piece 34 that is arc-shaped. A change of direction of the air volume flow of distribution goods from a substantially horizontal into a vertical direction of flow is achieved by means of said transition piece 34. A riser pipe 22 connects to the transition piece 34. The riser pipe 22 consists of different sections. To begin with, the riser pipe 22 has a nozzle 36. The cross section of the riser pipe 22 is first conically reduced and subsequently conically increased by means of said nozzle 36. Return devices 38 in the form of ring-shaped openings 40 are arranged at the location with the smallest cross section. The cross section reduction is intended for centering the air volume flow of distribution goods in the riser pipe 22. This is to be even further improved by a corrugated pipe 42 connecting to the nozzle 36. Other pipes with cross section reductions would also be conceivable apart from a corrugated pipe 42, for example such pipes as have recesses. It would also be conceivable to exchange the corrugated pipe 42 for a further nozzle 36, for example, such that the riser pipe is composed of two or more nozzles, for example. The individual sections of the riser pipe 22 can be in each case connected by way of welding or by means of clamps, for example. The sections can moreover be formed from a metallic or from a non-metallic material. In addition, the riser pipe 22 could be manufactured in one piece and made from plastic material, for example.

(11) A circular distributor head 24 connects to the top end of the riser pipe 22. Said distributor head 24 has a flat cover 44 in the exemplary embodiment of FIG. 2. The distributor head 24 could, however, also have many other forms, and could be, for example, mushroom-shaped or the like. In the distributor head 24, the air volume flow of distribution goods is redirected from a vertical direction to a horizontal direction toward the outflows 26, and for this purpose, the distribution goods can impact with the cover 44, for example, and are subsequently guided toward the outflows 26 by the air volume flow. The more uniform this distribution between the outflows 26 is, the more uniform is the lateral distribution of the distribution goods at the agricultural distribution machine.

(12) In order to be able to switch off or cut off, as the case may be, the dispensing of distribution goods in individual outflows 26, at least one of the outflows 26 has a shut-off device 28 associated with it. A pivotable track switch 30 is disposed within said shut-off device. In this instance, the track switch 30 can be pivoted, for example, by means of an electric and/or pneumatic and/or hydraulic and/or the like actuator between a shut position (cf. FIG. 2B) and an open position (cf. FIG. 2C). Besides a track switch 30, the shut-off device 28 further has a return section 45 in the form of a return connection 46, and has a seed tube connection 48 as well as a bypass 50. A return tube 52 is connected to the return connection 46, with the return tube 52 leading with its bottom end via a spout 54 into the return device 38.

(13) If the track switch 30 is, for example, closed (cf. FIG. 2B), the air volume flow of distribution goods in the shut-off device 38 is redirected toward the return section 45 and subsequently guided via a return tube 52 mounted to the return connection 46 and via the return device 38 back into the riser pipe 22. The returned distribution goods are subsequently received into the air volume flow of distribution goods in the riser pipe 22 again, and then conveyed to the distributor head 24 and to the outflows 26 again.

(14) While a pivotable flap is shown as track switch 30 in the context of the presently described exemplary embodiment, the track switch 30 can for all intents and purposes also have different designs. For example, a ball valve or the like is suitable as motor-adjustable track switch 30.

(15) In order to achieve a desired lateral distribution result even with a plurality of track switches 30 shut-off, it is necessary that, despite the track switches 30 being shut-off, an at least substantially same or uniform pressure level or a substantially same or uniform air volume flow or substantially same or uniform flow velocities, as the case may be, prevail in each case in the components of the distribution tower 22, independently of the position of the track switch 30. In order to achieve this result, the riser pipe 22, the distributor head 24, the return device 38, the return section 45, the bypass 50, as well as the seed tube connection 48 are permanently pneumatically connected, independently of the position of the track switch 30. In particular, this is ensured by the bypass 50 that is located in the shut-off device 28. In this way, various pressure levels are reached in the distribution tower 24, with a pressure level P1 resulting in the return device 38, and with a pressure level P2 and/or P3 resulting in the shut-off device 28 or in the bypass 50, as the case may be, and with P1 in this context being less than or equal to P2 and/or P3.

(16) FIGS. 3A and 3B show another exemplary embodiment of a distribution tower 10 of an agricultural distribution machine, with FIG. 3A showing the distribution tower 10 in a perspective view and FIG. 3B showing it in a cross-sectional side view. The distribution tower 10 essentially consists of a riser pipe 22, to the top end of which a distributor head 24 connects. A plurality of outflows or rows 26, as the case may be, is disposed evenly spaced along the circumference of the distributor head 24. The distribution tower 10 first has a transition piece 34 that is arc-shaped, with a reversal of direction of the air volume flow of distribution goods from a substantially horizontal into a vertical direction of flow being achieved by means of said transition piece 34. A riser pipe 22 connects to the transition piece 34, with the riser pipe 22 first having a nozzle section or a nozzle 36, as the case may be. The cross section of the riser pipe 22 is conically reduced and subsequently conically increased by means of said nozzle 36. The nozzle 36 is intended for centering the air volume flow of distribution goods in the riser pipe 22, whereby a subsequently even distribution of the distribution goods in the distributor head 24 is to be improved. Said centering is to be further improved by a pipe section that is designed as corrugated pipe 42 disposed downstream from the nozzle in the exemplary embodiment. Other pipe sections with cross section reductions would also be conceivable apart from a corrugated pipe 42, for example such pipes as have in each case only individual recesses. It would also be conceivable to exchange the corrugated pipe 42 for a further nozzle 36, for example, such that the riser pipe 22 is composed of two or more nozzles, for example. The individual sections of the riser pipe 22 can be in each case connected by way of welding or by means of clamps, for example. The sections can moreover be formed from a metallic or from a non-metallic material. In addition, the riser pipe 22 could be manufactured in one piece and made from plastic material, for example.

(17) A circular distributor head 24 having a flat cover 44 connects to the top end of the riser pipe 22. In the distributor head 24, the air volume flow of distribution goods is redirected from a vertical direction to a horizontal direction toward the outflows 26, and for this purpose, the distribution goods can impact with the cover 44, for example, and are subsequently guided toward the outflows 26 by the air volume flow. The more uniform this distribution between the outflows 26 is, the more uniform is the lateral distribution of the distribution goods at the agricultural distribution machine.

(18) In order to be able to switch off or cut off, as the case may be, the dispensing of distribution goods in individual outflows 26, each of the outflows 26 has a shut-off device 28 associated with it. A pivotable track switch 30 is disposed within said shut-off device. The track switch 30 can be pivoted, for example, by means of an electric and/or pneumatic and/or hydraulic and/or the like actuator between a shut position (cf. FIG. 3B, right side) and an open position (cf. FIG. 3B, left side). Besides a track switch 30, the shut-off device 28 further has a return section 45 consisting of a return connection 46, and has a seed tube connection 48 as well as a bypass 50. First, a collecting piece 56 is connected to the return connection 46. Said collecting piece 56 is designed to be y-shaped in the exemplary embodiment, and it connects in each case two return connections 46 or two shut-off devices 28, as the case may be. A return tube 52 is moreover connected to the collecting piece 56, with the return tube 52 leading with its bottom end via a spout 54 into the return device 38. The number of return tubes 52 can be substantially reduced by using the collecting pieces 56, with at least two, but also more return tubes 52 being potentially connected here.

(19) The return device 38 is formed by a circular pipe surrounding the nozzle 36 or the riser pipe 22, as the case may be, with a multitude of rectangular openings 40 being associated with the nozzle 36 in the area of its smallest circumference, which openings 40 establish a connection between the riser pipe 22 or the nozzle 36, as the case may be, and the return device 38. The arrangement of the openings 40 in the area of the nozzle 36 results in a suction effect at the openings, whereby the seed return from the return device 38 into the riser pipe 22 is further improved.

(20) When the track switch 30 is shut (right side in FIG. 3B), the air volume flow of distribution goods in the shut-off device 38 is redirected toward the return section 45, and is guided back into the riser pipe 22 by means of the return connection 46, the collecting pieces 56, the return tube 52, and the return device 38. The returned distribution goods are subsequently conveyed by the air volume flow of distribution goods in the riser pipe 22 to the distributor head 24 and to the outflows 26 again.

(21) In order to still achieve a desired lateral distribution result even with at least one shut track switch 30, it is necessary that, despite the track switch 30 being shut-off, the pressure P1 in the return device 38 or at the spout 54, as the case may be, is less than or equal to the pressure P2/P3 in the bypass 50 or in the return section 45, as the case may be.

(22) In order to achieve this result, the riser pipe 22, the distributor head 24, the return device 38, the return section 45, the bypass 50, as well as the seed tube connection 48 are permanently pneumatically connected, independently of the placing or position of the track switch 30, as the case may be. In particular, this is ensured by the bypass 50 that is located in the shut-off device 28. In this way, various pressure levels are reached in the distribution tower 24, with a pressure level P1 resulting in the return device 38, and with a pressure level P2 or P3 resulting in the shut-off device 28 or in the bypass 50, respectively, and with P1 largely being less than or equal to P2 and P3, independently of the number of shut track switches 30.

(23) The pressure connection in the distribution tower 10 is once more illustrated by the lines in FIG. 3A, with a pressure level P1 prevailing in the return device 38 surrounding the riser pipe 22. By means of the spouts 54 mounted along the circumference of the return device 38, by means of the return tube 52, of the collecting pieces 54, of the return connections 46, as well as by means of the bypass 50, a pneumatic connection is in each case established between these components, whereby a pressure level in each case of P2 and/or P3 is reached in the shut-off devices 28. Said pressure level also prevails, in particular, in the area of the seed tube connection 48, with P1 in this context again in each case largely being less than or equal to P2 and/or P3, independently of the number of shut track switches 30 or outflows 26, as the case may be. It is thus possible to connect an optional number of outflows 26 to the distribution tower 10 without the lateral distribution perceptibly changing.

(24) In order to achieve even better results, the amount of distribution goods metered from the metering device 16 into the duct system can be reduced in each case depending on the number of shut outflows 26, with this being only necessary from a certain number of shut outflows 26 onward, for example from five outflows 26 onward.

(25) A possible design for a shut-off device 28 with integrated track switch 30 follows from FIGS. 4A and 4B, with the track switch 30 being represented in a shut position in FIG. 4A and in an open position in FIG. 4B. The shut-off device 28 consists of a flange surface 58 for mounting to the particular outflows 26 of the distributor head 24. For this purpose, there are latching members 60, for example, disposed at the flange surface 58. Said latching members 60 allow for simple and quick mounting to the distributor head 24. The shut-off device moreover has a return section 45 being preferably composed of a return connection 46 and a return channel 64 extending between the flange surface 58 and the return connection 46, and also has a seed tube connection 48 and a seed channel 62 extending between the flange surface 58 and the seed tube connection 48, with a bypass 50 moreover extending between the return connection 46 and the seed tube connection 48. The flange surface 58, the return connection 46, as well as the seed tube connection 48 have an essentially same outer diameter D1; D2; D3 of, for example, 30 millimeters, while said diameters could also be selected to be larger or smaller and could differ from each other.

(26) Following the flange surface 58, there is a track switch 30 that can be pivoted between a shut position (cf. FIG. 4A) and an open position (cf. FIG. 4B). Said pivoting is carried out preferably by means of an electric and/or pneumatic and/or hydraulic and/or the like actuator. The control of the actuator can be carried out, for example, by means of the computer unit located at the agricultural machine. The computer unit can in turn transmit corresponding signals to the actuator by manual input, for example, or based on GPS data. The air volume flow of distribution goods can be conveyed according to the position of the track switch 30; with an open position, it can be conveyed toward the seed tube connection 48 as well as toward a spreading device, and with a shut position, it can be conveyed toward the return connection 46 as well as toward the riser pipe 22.

(27) The seed channel 62 and the return channel 64 can be disposed at right angles to each other, and the seed channel 62 can in turn be disposed to be horizontal to the flange surface 58 and the return channel 64 can be disposed perpendicular to the flange surface 58. In the exemplary embodiment of FIGS. 4A and 4B, the seed channel 62 and the return channel 64 are furthermore substantially pneumatically separated by way of the track switch 30, although this is not absolutely necessary, since the track switch can also serve as bypass if accordingly designed.

(28) A portion of bypass 50 extends parallel to the seed channel 62 and another portion of the seed channel 62 extends parallel to the return channel 64, with said bypass 50 pneumatically connecting the return connection 46 as well as the seed tube connection 48. The bypass is disposed such that it forms a separator or a separating section 66, as the case may be, in the form of a deflection separator. In this instance, the deflection separator has an angle of approximately 180, whereby the distribution goods are prevented from escaping via the bypass. The degree of separation has to be as high as possible in this context, so that the distribution goods are guided back toward the return connection 46 into the riser pipe 22 when the track switch 30 is shut, while the air volume flow, however, can escape via the bypass 50 toward the seed tube connection 48. The separation of distribution goods from a part of the air volume flow is achieved by way of the separating section 66.

(29) The bypass 50 has a cross section that is selected such that the flow resistance is as far as possible the same for the bypass 50 with the track switch 30 shut as for the seed channel 62 with the track switch 30 open. In this context, the cross section or the width of the bypass 50, as the case may be, is, for example, 30 millimeters or 25 millimeters or 20 millimeters. Thus, the flow resistance, for example, in a path along the flange surface 58, the return channel 64, the separating section 66, the bypass 50, and the seed tube connection 48 is substantially the same as a flow resistance in a path along the flange surface 58, the seed channel 62, and the seed tube connection 48.

(30) The outer contour of the seed channel 62 moreover has a deflection contour 68. A change of direction of the air volume flow of distribution goods, for example from a horizontal direction to a direction along the seed tube, is achieved by said deflection contour 68. An impact sensor, for example, could be associated with said deflection contour 68, with the number and/or amount of passing grains of distribution goods being determined by means of the impact sensor. Optical sensors could also be provided in this context. In a preferred embodiment, the position of the track switch 30 could be adjusted corresponding to the sensor values, that is to say that if the sensor determines that a desired amount of distribution goods has been exceeded, the track switch 30 shuts or assumes a position, as the case may be, where more distribution goods are guided toward the return section 45, and vice versa.

(31) FIG. 5 shows a further embodiment variant of a distribution tower 10 according to the invention, this embodiment having a pressure compensation device 70 (cf. FIG. 2). The distribution tower 10 essentially consists of a riser pipe 22, to the top end of which a distributor head 24 connects. A plurality of outflows 26 is disposed evenly spaced along the circumference of the distributor head 24. The distribution tower 10 first has a transition piece 34 that is arc-shaped. A change of direction of the air volume flow of distribution goods from a substantially horizontal into a vertical direction of flow is achieved by means of said transition piece 34. A riser pipe 22 connects to the transition piece 34. The riser pipe 22 consists of different sections. To begin with, the riser pipe 22 has a nozzle 36. The cross section of the riser pipe 22 is first conically reduced and subsequently conically increased by means of said nozzle 36. Return devices 38 in the form of ring-shaped openings 40 are arranged at the location with the smallest cross section. The cross section reduction is intended for centering the air volume flow of distribution goods in the riser pipe 22. This is to be even further improved by a corrugated pipe 42 connecting to the nozzle 36. Other pipes with cross section reductions would also be conceivable apart from a corrugated pipe 42, for example such pipes as have in each case only individual recesses. It would also be conceivable to exchange the corrugated pipe 42 for a further nozzle 36, for example, such that the riser pipe 22 is composed of two or more nozzles, for example.

(32) A circular distributor head 24 connects to the top end of the riser pipe 22. Said distributor head 24 has a flat cover 44 in the exemplary embodiment of FIG. 5. The distributor head 24 could, however, also have many other forms, and could be, for example, mushroom-shaped or the like. In the distributor head 24, the air volume flow of distribution goods is redirected from a vertical direction to a horizontal direction toward the outflows 26, and for this purpose, the distribution goods can impact with the cover 44, for example, and are subsequently guided toward the outflows 26 by the air volume flow. The more uniform this distribution between the outflows 26 is, the more uniform is the lateral distribution of the distribution goods of the agricultural distribution machine.

(33) In order to achieve a desired lateral distribution result independently of external influences, such as seed tube lengths or the like, it is necessary to establish an at least substantially same or uniform pressure level or substantially same or uniform air volume flows or substantially same or uniform flow velocities, as the case may be, in each case in the components of the distribution tower 22. In order to achieve this result, the riser pipe 22, the return device 38, the bypass 50, as well as the seed tube connection 48 are permanently pneumatically connected. In this way, various pressure levels are reached in the distribution tower 24, with a pressure level P1 resulting in the return device 38 in this context, and with a pressure level P2 and/or P3 resulting in the pressure compensation device 70, and with P1 in this context being less than or equal to P2 and/or P3.

(34) The pressure compensation device 70 shown in this exemplary embodiment could be combined, in particular, in connection with the shut-off devices 38 shown in FIGS. 2 to 4, so that only a small number of outflows 26 of a distribution tower 10, for example, are provided with shut-off devices 28, and the remaining outflows 26 are each provided with pressure compensation devices 70. The benefit herefrom would be that the distribution tower 10 would still have all advantages of the pressure levels that are reached, but could be constructed in a substantially simpler manner, since only a small number of outflows would have to be provided with track switches 30 and corresponding actuators.

(35) The invention has been described with reference to a preferred embodiment. Those skilled in the art will appreciate that numerous changes and modifications can be made to the preferred embodiments of the invention and that such changes and modifications can be made without departing from the spirit of the invention. It is therefore intended that the appended claims cover all such equivalent variations as fall within the true spirit and scope of the invention.

LIST OF REFERENCE CHARACTERS

(36) 10 Distribution tower 12 Agricultural machine 14 Storage hopper 16 Metering device 18 Duct system 20 Air blower 22 Riser pipe 24 Distributor head 26 Outflow, row 28 Shut-off device 30 Track switch 32 Seed tube 34 Transition piece 36 Nozzle 38 Return device 40 Opening 42 Corrugated pipe 44 Cover 45 Return section 46 Return connection, return opening 48 Seed tube connection 50 Bypass 52 Return tube 54 Spout 56 Collecting piece 58 Flange surface 60 Latching member 62 Seed channel 64 Return channel 66 Separating section 68 Deflection contour 70 Pressure compensation device