Method for metering granular material and apparatus for metering granular material

Abstract

A method for metering granular material, such as seeds, fertilizer, or the like. By way of the method, the granular material being carried and conveyed by an airflow is directed through a feed tube into a metering unit, and guided therein along an approximately circular arc path and tangentially directed into an outlet tube, which is adjacent to the metering unit. The airflow being guided through the outlet tube and carrying and conveying the granular material, which is being conveyed in approximately equal spacing, is conveyed and/or accelerated within the metering unit by means of at least one conveyor disk or fan disk, which is electromotively driven at a regulatable rotational speed and which rotates approximately concentrically within the metering unit. The drive speed is increased or reduced based on a detected torque of the electromotive drive of the at least one rotating conveyor disk or fan disk.

Claims

1. A method for metering granular material within a distribution unit of a distribution machine wherein the granular material is carried and conveyed in approximately equal spacing by an airflow directed through a feed line and into a metering unit wherein the airflow and granular material is guided within the metering unit along an approximately circular arc path and is tangentially directed into an outlet tube positioned adjacent to the metering unit, wherein the airflow carrying and conveying the granular material directed through the outlet tube is moved within the metering unit by means of at least one conveyor disk or fan disk, which is electromotively driven at a regulatable rotational speed and which rotates approximately concentrically within the metering unit, and wherein the rotational speed of the at least one conveyor disk or fan disk is increased or reduced based on a torque of an electromotive drive of the at least one rotating conveyor disk or fan disk.

2. The method as recited in claim 1, wherein the torque of the electromotive drive is derived from its electrical current consumption.

3. The method as recited in claim 1, wherein the rotational speed of the electromotive drive is increased or reduced based on a detected torque of the electromotive drive until the detected torque is within a definable target range.

4. The method as recited in claim 1, wherein the rotational speed of the electromotive drive is increased when the torque is above a target range.

5. The method as recited in claim 4, wherein the rotational speed of the electromotive drive is approximately continuously increased or reduced.

6. The method as recited in claim 4, wherein the rotational speed of the electromotive drive is increased or reduced at pre-definable intervals.

7. The method as recited in claim 1, wherein the rotational speed of the electromotive drive is reduced when the torque is below a target range.

8. The method as recited in claim 1, wherein values from a grain flow sensor arranged in the outlet tube are analyzed and used in the regulation of the rotational speed of the electromotive drive.

9. The method as recited in claim 1, wherein the approximately equally spaced and conveyed granular material is carried entirely or in part by airflow discharged and exiting the metering unit through the outlet tube.

10. The method as recited in claim 1, wherein the granular material is guided within the metering unit at least in part via mechanical support and is carried along an inner surface, wherein approximately equal spacing of individual grains of the granular material is imposed as the grains approach the outlet tube.

11. The method as recited in claim 1, wherein the airflow carrying the granular material is guided uninterruptedly from the feed line through the metering unit, and to the outlet tube.

12. The method as recited in claim 1, wherein the airflow guided through the outlet tube and carrying and conveying the granular material is accelerated within the metering unit.

13. The method as recited in claim 1, wherein the airflow enters into and exits from the outlet tube at a speed that is greater than a feed speed at which the airflow enters into the feed line.

14. A regulatable arrangement for metering granular material within a distribution unit of a distribution machine, wherein the granular material is carried and conveyed in approximately equal spacing by an airflow directed through a feed line and into a metering unit, wherein the airflow and granular material is guided within the metering unit along an approximately circular arc path and is tangentially directed into an outlet tube positioned adjacent to the metering unit, with at least one conveyor disk or fan disk, which is electromotively driven at a regulatable rotational speed and which rotates approximately concentrically within the metering unit to circulate within the metering unit the airflow carrying and conveying the granular material directed through the outlet tube, and with at least one device operable to detect a torque of an electromotive drive of the at least one rotating conveyor disk or fan disk and is further operable to vary a speed of the electromotive drive if a detected torque is outside of a definable target range.

15. The arrangement as recited in claim 14, wherein devices for the detection and evaluation of sensor values from at least one grain flow sensor positioned in the outlet tube, wherein the sensor values are used to regulate the speed of the electromotive drive.

16. A sowing apparatus for granular material, comprising a plurality of rows located next to each other, each row comprising a sowing unit or seed drill coulter for placing individual grains of the granular material into the soil at a definable placement depth, wherein the sowing units or seed drill coulters are supplied with granular material from at least one grain storage hopper via respectively separate feed tubes, wherein each of the sowing units or seed drill coulters is equipped with one regulatable arrangement for metering granular material as recited in claim 14, wherein each of the regulatable arrangements for metering granular material are in communication with a central control unit operable to process motor torques measured in the metering units, and is further operable to regulate a distance between grains for each sowing unit or seed drill coulter by varying a drive speed of the electromotive drive of each sowing unit or seed drill coulter to achieve a grain spacing or longitudinal distribution of grains within a predetermined target value.

17. The sowing apparatus as recited in claim 16, wherein at least one grain flow rate sensor is arranged in each of the outlet tubes, wherein each of the grain flow rate sensors is in communication with the central control unit, wherein the central control unit is further operable to use sensor values of the grain flow rate sensors to regulate the spacing or the longitudinal distribution of the granular material.

18. A metering apparatus for granular material within a distribution unit or sowing unit of a distribution machine or sowing machine wherein granular material is carried and conveyed by an airflow directed through a feed line into a metering unit and guided within the metering unit along an arcuate path and into an outlet tube adjacent to the metering unit, wherein the metering unit comprises at least one rotating element electromotively driven at a regulatable rotational speed, wherein the rotating element rotates approximately concentrically within the metering unit for the circulation of air and granular material within the metering unit and out through the outlet tube with the granular material being conveyed in the outlet tube in approximately equal spacing, wherein the metering system further includes at least one torque sensor for detecting a torque of an electromotive drive of the at least one rotating element, wherein the at least one torque sensor is in communication with a controller operable to vary a speed of the electromotive drive if a torque detected by the torque sensor is outside of a definable target range.

19. The metering apparatus as in claim 18 further comprising at least one grain flow sensor arranged in the outlet tube and in communication with the controller for adjusting the speed of the electromotive drive in response to a value detected by a grain flow sensor, the value corresponding to the flow of granular material.

20. The metering apparatus as in claim 18 further comprising at least one sensor for detecting a drive speed of the distribution machine or sowing machine and in communication with the controller for adjusting the speed of the electromotive drive in response to the detected drive speed.

21. A method for metering granular material within a distribution unit or sowing unit of a distribution machine or sowing machine in which granular material is carried and conveyed by a stream of air directed through a feed line into a metering unit and guided therein along an approximately circular arc path and into an outlet tube adjacent to the metering unit, wherein the method comprises electromotively driving a drive motor connected to at least one conveyor disk or fan disk which rotates approximately concentrically within the metering unit for moving or circulating the stream of air within the metering unit, and adjusting a speed of the drive motor on the basis of a detected torque of the drive motor.

22. The method as in claim 21, wherein the detected torque of the drive motor is derived from an electrical current consumption of the drive motor.

23. The method as in claim 21, wherein the speed of the drive motor is increased or reduced based on the detected torque of the drive motor of the at least one rotating conveyor disk or fan disk until the detected torque is within a definable target range.

24. The method as in claim 21 further comprising analyzing a detected value of a grain flow sensor arranged in the outlet tube and using the detected value of the grain flow sensor to adjust the speed of the drive motor.

Description

(1) In the following passages, the attached figures further illustrate exemplary embodiments of the invention and their advantages. The size ratios of the individual elements in the figures do not necessarily reflect the real size ratios. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged in relation to other elements to facilitate an understanding of the invention.

(2) FIG. 1 shows a schematic illustration of a pneumatically operating sowing machine with volumetrically-metered seeds, which are guided via a central distributor to individual seed tubes with seed drill coulters arranged thereat on the side of the outlets.

(3) FIG. 2 shows the basic construction of a metering apparatus according to the invention in a schematic illustration, which metering apparatus is arranged in line with a seed tube of a sowing machine according to FIG. 1.

(4) FIG. 3 shows a schematic illustration of an alternative embodiment of a sowing machine with a plurality of sowing units, which are each equipped with metering apparatuses according to FIG. 2.

(5) The same or equivalent elements of the invention are designated by identical reference characters. Furthermore and for the sake of clarity, only the reference characters relevant for describing the respective figure are provided. It should be understood that the detailed description and specific examples of the device and method according to the invention, while indicating preferred embodiments, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

(6) The schematic illustration of FIG. 1 shows a pneumatically operating sowing machine 10 with volumetrically-metered seeds, which are guided via a central distributor to individual seed tubes with seed drill coulters arranged thereat on the side of the outlets. The sowing machine 10, the basic construction of which is known from the prior art, typically has a funnel-shaped storage hopper 12 for granular material, in particular for seeds, at the underside of which storage hopper 12 is a metering device 14, which meters the granular material or the seeds, respectively, into an air stream 16, which is generated by an air blower 18 and conveyed into an air duct 20, which leads to a vertically arranged riser pipe 22. A central distributor 24 is arranged at a top side of the riser pipe 22which can be, for instance, a so-called corrugated pipe or the likewhich central distributor 24 distributes the grain-bearing air stream 26 as evenly as possible to a multitude of seed tubes 28. The individual seed tubes 28, only one of which is shown for the sake of clarity, each eventually lead to seed drill coulters 30 with which the seeds are placed into the soil 32. The metered feeding of the seeds or granular material released from the storage hopper 12 into the air stream 16 can be optionally carried out according to the Venturi principle or also by support of the seeds that are located, under pressure, in the closed pressure tank 12.

(7) As can be discerned from FIG. 1, a metering apparatus 34 according to the invention is located in line with the seed tube 28, typically in the immediate vicinity to the seed drill coulter 30, which metering apparatus 34 provides for supplying the seed drill coulter 30 with granular material or with seeds, respectively, which is or are released at approximately equal grain spacing and at largely the same respective conveying speeds into the soil 32. Since in a real sowing machine a multitude of such parallel seed drill coulters 30 are provided (for example twenty-four, thirty-two, or more), which are each connected with separate seed tubes 28 and supplied by them, a corresponding number of metering apparatuses 34 according to the invention, which are each constructed in the same manner, are also provided, because each individual seed tube 28 has such a metering apparatus 34.

(8) FIG. 2 shows the basic construction of a metering apparatus 34 according to the invention in a schematic illustration, which metering apparatus 34 is arranged in line with a seed tube 28 of a sowing machine 10 according to FIG. 1. The grain-bearing air stream 26 thus tangentially streams as feed air 36 at a first speed v.sub.1 through a feed tube 38 arranged in line with the seed tube 28 into the metering apparatus 34, wherein the feed air 36 can be accelerated by means of a conveyor disk and/or fan disk 42 rotating in the metering unit 40 of the metering apparatus 34. The grains (for instance, seeds) being carried and conveyed in the feed air 36 are thereby simultaneously sorted and brought into an order relative to each other in such a manner that they have approximately the same spacing from each other upon tangentially exiting the metering unit 40 into an outlet tube 44. The conveying air 46 or grain-bearing airflow, which is accelerated in the metering unit 40, exits from the outlet tube 44 at a higher speed (v.sub.2) than that at which it enters into the feed tube 38, such that the following applies:
v.sub.2>v.sub.1.

(9) Both the feed tube 38 and the outlet tube 44 end respectively approximately tangentially at the metering unit 40 of the metering apparatus 34, in which the air, together with the carried and conveyed grains, undergoes a deflection of preferably at least 330 degrees, typically of approximately 360 degrees. The outlet tube 44 can subsequently lead into a seed tube (cf. FIG. 3), which leads to the seed drill coulter 30 (cf. FIG. 1), with which the grains are placed into the soil 32. The outlet tube 44 can optionally have a crescent-shaped curvature, which takes up the curvature of the air conveyance path within the metering unit 40 and continues it with a larger radius of curvature.

(10) As can be discerned from the schematic illustration of FIG. 2, the air stream is guided uninterruptedly from the supply (air blower 18) to the release at the seed drill coulter 30 (cf. FIG. 1) such that the complete air stream passes through the entire system before exiting at the seed drill coulter 30 together with the transported and largely equidistantly released grains.

(11) The conveyor disk and/or fan disk 42 in the metering unit 40 is electromotively driven, which is carried out via the schematically indicated electric drive motor 48. Normally, the grains areat least partlyseparated from the air stream within the metering unit 40, where the grains being guided on the outside also describe a circular arc movement when they are guided along the inner cover surface of the metering unit 40. The air stream is normally guided on a smaller radius in the inner area of the metering unit 40 and can swirl there, as the case may be, before again carrying away the grains having been delivered into the outlet tube 44 at its tangential outlet, which grains were previously accelerated by the metering unit 40 and are continuously surrounded by flowing air. The grains being conveyed with the air 46 exiting through the outlet tube 44 are particularly suited for the precise placement into the soil 32 because their speed and position are controllable very accurately. The method shown provides for the desired grain acceleration within the metering unit 34 or 40, respectively, and can largely do without further auxiliary means, such as an additional air supply.

(12) The seeds initially move at a constant speed (v.sub.1), which is predetermined by the air speed of the conveying air 26. This conveying air 26 originates from the central air supply of the pneumatic sowing machine 10, in which the grains are metered into the air stream 16, which originates from the air blower 18 (Venturi principle or pressure tank principle). The air speed is increased in the metering apparatus 34 by the rotation of the mechanically operated conveyor disk/fan disk 42, whereby the air speed (v.sub.2) of the air exiting from the outlet tube 44 is increased and thus also the conveying speed for the grains. These are subsequently released nearly without breaking to the seed conduit.

(13) The power consumption of the electric drive motor 48 is detected, the detection being carried out at a given supply voltage U, for instance, by measuring the current consumption I such that the power consumption P can be derived or calculated, respectively, from the known product
P=U.Math.I.

(14) Since the power consumption P in the metering unit 40 according to the invention provides a direct correlation to the torque to be delivered by the motor, the grain flow within the metering unit 40 can be stabilized by the drive speed being increased or reduced on the basis of a detected torque of the electromotive drive 48 for the rotating conveyor disk or fan disk 42 until the detected torque is within a definable target range. The drive speed is increased if an increased torque, which is above the target range, is measured as well. By contrast, the drive speed is reduced if a lower torque, which is below the target range, is measured as well. The increase or reduction of the rotational speed can be optionally carried out continuously or also at predefinable intervals.

(15) In the manner described, the spreading rate of granular material or seeds, respectively, can be regulated by means of the degree of filling of the metering apparatus 34. The greater the degree of filling with seeds in the meter 34, the more grains are separated and spread. Since each meter 34 or each metering unit 40, respectively, has a separate drive motor 48 by which the fan disk 42 in the metering unit 40 is driven, the drive torque of this drive motor 48 can be detected and used for regulating the spreading rate. Since the drive torque of the motor 48 increases with the degree of filling of the meter 34, the detected torque can be used as measured for determining and regulating the degree of filling. In this manner, the quantity that is spread can be regulated; i.e. for a certain spreading rate, the torque of the drive motor 48 may only have a certain value. The object of an improved evenness of the seeds being spread can be achieved by an adjustment of the motor speed on the basis of the measured drive torque, whereby stronger fluctuations in the spreading rate of an individual meter can be compensated for or suppressed in a desired manner. Although the spreading rates can still vary between the individual rows in this manner, the object of optimized and preferably non-fluctuating grain spacing within the row is achieved.

(16) Optionally, grain sensors (not illustrated here) for monitoring the quantity of grain released by the meter can be arranged in the downpipes such that these sensor values can be used for the further regulation of the drive motors 48.

(17) In a further schematic illustration, FIG. 3 shows an alternative embodiment of a sowing machine 10, which is equipped with a plurality of seed drill coulters arranged next to each other, and upstream from which each of the metering apparatuses 34 according to FIG. 1 or FIG. 2, respectively, is arranged. The configuration of the seed drill coulters 30 or the sowing units, respectively, and of the metering apparatuses 34 is without relevance for the following explanation of the alternative embodiment of the invention and can correspond, for example, to the arrangement according to FIG. 1. The seed tubes 28 leading to the sowing units or to the metering apparatuses 34, respectively, through which seed tubes 28 the grain-bearing air stream 26 is directed to the metering apparatuses 34, are only indicated in FIG. 3. The seed tubes 28 can be supplied from a central storage hopper or also from a plurality of supply tanks with seeds located therein (cf. FIG. 1).

(18) According to the embodiment variant shown in FIG. 3, the metering apparatuses 34 are respectively connected, in terms of signal technology, with a central control unit and/or regulating unit 50, which, on the one hand, detects and processes the torques 52 and/or rotational speed values, which are detected in the metering apparatuses 34, for the drive motors 48 of the rotating fan disks or conveyor disks 42 (cf. FIG. 2). If necessary and/or according to predefined grain spacings, further spreading parameters, such as a driving speed 54, can furthermore be detected. The rotational speeds of the drive motors 48 are regulated and adjusted in the desired manner in dependence on the detected values 52, 54 and under consideration of target values 56 for the grain spacing or the respective longitudinal distribution of the spread grains in the furrow, respectively. The regulation specifications for the drive motors 48 in the metering apparatuses 34 are denoted by the reference numbers 58. The target values 56 are derived from, for instance, characteristic values and/or from specifications from the user, who can enter these manually.

(19) Optionally, additional sensor values 60 from optional flow rate sensors (not illustrated here) can be analyzed, which flow rate sensors are located, for instance, in sections of the grain tubes arranged downstream from the metering apparatuses 34, and which can detect both the passing grains per time interval and the grain spacing, for instance, by means of optical, inductive, or also mechanical detection. By the corresponding configuration of the control unit and/or regulating unit 50, an entire, multi-row sowing machine 10, which is equipped with a multitude of controllable and regulatable metering apparatuses 34, can thus be variably controlled or regulated, respectively, with regard to its grain quantity per seed row and in particular also with regard to the longitudinal distribution of the grains or seeds.

(20) It can furthermore be advantageous to also provide such flow rate sensors or grain flow sensors in the respective feed tubes or seed tubes 28 to the metering unit 34 so that a facilitated control based on these grain flow sensors is made possible. Under certain conditions, it can thus be prevented that individual metering units 34 are charged with too large a quantity of grains and thus plugged up, which, according to measuring conditions, cannot be detected with the same reliability by a grain flow sensor in the outlet tube 44. Such quantity sensors can operate, for instance, inductively or with impact surfaces, which can detect the grain quantities respectively passing through the tubes.

(21) 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

(22) 10 Sowing machine

(23) 12 Storage hopper

(24) 14 Metering device

(25) 16 Air stream

(26) 18 Air blower

(27) 20 Air duct

(28) 22 Riser pipe (corrugated pipe)

(29) 24 Central distributor, central distribution

(30) 26 Grain-bearing air stream, grain-bearing airflow

(31) 28 Seed tube

(32) 30 Seed drill coulter

(33) 32 Ground, soil

(34) 34 Metering apparatus

(35) 36 Feed air, feed airflow

(36) 38 Feed tube

(37) 40 Metering unit

(38) 42 Disk, conveyor disk, fan disk

(39) 44 Outlet tube

(40) 46 Exiting air (air exiting the metering apparatus)

(41) 48 Drive motor, electric drive motor

(42) 50 Central control unit and/or regulating unit

(43) 52 Torque, torque value

(44) 54 Running speed

(45) 56 Target values

(46) 58 Regulation specifications, control data

(47) 60 Additional sensor values