DE3902000C2 - Centrifugal spreader - Google Patents

Description

The invention relates to a centrifugal spreader according to the Preamble of claim 1.

As with all types of spreader, you are also with a slingshot spreading carefully, one possible over the spread as uniform a distribution of the spreading material, that is a constant spreading density over the spreading width achieve. This goal is most likely at relatively small Spreading quantities and / or small spreading widths reached. The Scatter pattern then shows a flat-triangular course, its maximum (peak) in the middle behind the spreader lies and falls flat on both sides. The the actual working width of the spreader is the width at which 50% of the desired spread rate was spread are. Appropriate connection travel can then Overlap of the scatter patterns can be achieved in such a way that the spreading amounts of each trip add up so that over the  the entire sprinkled area is approximately uniform Scattering density is obtained. The larger the spread rate, which also increases with the spread, moreover the spreading pattern falls more steeply to the side and so on It is more difficult to do so by connecting To achieve overlap of the scatter patterns, which lead to a leads to even spreading density. There is also one Increasing the effective working width. Furthermore in the middle area overfertilization found what in primarily due to the so-called impact losses is to be fed. These are those litter good particles that are not controlled by the spreader vanes be detected, but when the throwing wing enters the fertilizer jet through impact processes in any direction accelerated or distracted.

With even larger spreading quantities / spreading width the spreading shows picture in addition to a strong cant in the middle behind the centrifugal spreader, mainly on the front impact losses mentioned is attributable to each side another increase. So overall there is a undulating course of the scatter pattern with outwards relatively steep slopes. Since with larger ar the width of the spreading material is also larger, one speaks here of the so-called "quantity effect" limit compared to the aforementioned "impact effect". The irregularity in the Scattering pattern cannot be eliminated when connecting.

To the negative effects, especially the "quantities effective ", for example, instead of two Spreader vanes four spreader vanes on the sym arranged metrically. The - only minor - Ver Improvement in the "quantity effect" leads usually worsening in impact  of the "impact effect". They also tried the problem to counter the spreading material by means of adjustable spreader vanes depending on the spread, different exit angles procure. With all known measures, it all happens if to a slight improvement, but not to an even approximate elimination of the disadvantageous Consequences of the "quantity effect" and the "impact effect".

In practice, spreader vanes have a U-shaped cross proved to be particularly favorable because it a kind of disc enters the downflow of the grit cut out of the spreading material. The majority of Spreading material is picked up by the spreader wing and zen accelerated trifugally, nevertheless a not unimportant tender part of the particles in the area of the upper leg of the U-profile and from its leading edge in all Directions reflected. These impact losses are all the more the greater the distance between the outlet chute and spreader is.

In a known spreader (DE 78 35 966 U1) with a curved The spreading material is inclined by a provided delivery shaft in the area of the inner edge of the Thrown shovel. To reflect the upward Capturing particles is at the top of the dispenser a shaft leading up to the spreader vanes sheet provided. With that, however, they become at most reduced impact losses resulting from reflections result upwards.

The invention is based, with one Centrifugal broadcaster according to the preamble of claim 1 to reduce the impact losses and thus an even to achieve a smaller spread pattern.  

This object is achieved in that the at least the upper leg of the U-profile of each spreading wing with its leading edge and in that at the outlet shaft passing section in a plane parallel to the Lower edge of the discharge chute with a short distance below this is arranged and that in the center of the slingshot a cylindrical cap is arranged, which the lower edge of the outlet shaft that is close to her towered above.

While in the known centrifugal spreaders with two or four throwing wings caused by uncontrolled reflections when immersing the spreading vane in the spreading material jet bouncing particles are mainly in the middle collect behind the spreader and there to one lead to a disproportionately large scatter density Particles through the assignment of Aus according to the invention barrel and upper leg of the spreader wing of the Spreader vanes are caught so that these particles get through the spreader vanes are accelerated outwards and in con trolled leave the throwing wing. Through the Cap in the center of the centrifugal disc, over the sub edge of the outlet shaft protrudes upwards and near the Outlet shaft is arranged, the inside right flexed particles back towards the spreader wing thrown.

A preferred embodiment is characterized in that the upper leg of each spreader wing advance from its the edge against the direction of rotation to form a Clearance angle is inclined downwards.

Regardless of the inclination of the spreader vanes opposite the horizontal, especially one for large ones  Spreading width provided plate-like formation of the Centrifugal disc with the throwing vanes facing outwards rise, it is ensured that the upper leg always immediately below the lower edge of the outlet shaft passed by. This will reduce the number of particles the in the gap between the upper leg and the Bottom edge of the outlet chute get and not enough accelerated accordingly, minimized. By continuing provided clearance angle, under which the upper leg is turned on, it follows that the spreading wing only with the leading edge hits the fertilizer jet, while those exiting behind the leading edge Fertilizer particles fall on the inclined open area and mainly to the rear and towards the slingshot disc are reflected so that they are from the next throw wings can be detected. Furthermore, through the Frei angle of the backlog of the fertilizer jet in the outlet shaft, which leads to an uncontrolled change in the throughput zes leads, reduces or avoids.

Another advantageous embodiment stands out characterized in that the leading edge of the upper leg each spreader wing attaches to the web at its inner end and curving forward into a straight line, if necessary, a section parallel to the web passes over, it is also advantageous if each spreader wing with its inner end over the center of the slinger beyond the other side.

This embodiment ensures that the front Running edge of the spreading wing when entering the fertilizer always hits the fertilizer particles so that they accelerated to the outside. The exact off Formation of the curvature and extension of the throwing wing  at its inner end to the respective location and shape of the Outlet opening or the outlet shaft are adjusted.

In a further preferred embodiment it is provided that the upper leg of each spreader wing in its outer ab cut that - seen from the center of the slinger - is located beyond the outlet shaft, is arranged higher than the lower edge of the outlet shaft.

While the upper leg in the area of the outlet shaft runs just below its lower edge the leg in the outer section of the spreader wing above the lower edge of the outlet shaft with the result that the - seen from the center of the slinger - elegant Lich rebounding particles from the higher lying trapped leg and deflected into the spreader wing to get out from this in a controlled manner to be accelerated.

The measure that the web of the U- Profiles of each throwing wing in its outer section with his at the transition to the higher leg inner edge on a radius of the centrifugal disc lies which is little larger than that which is radially on furthest outer boundary of the outlet shaft.

The inner edge of the web at the transition to the higher one Leg section therefore runs directly on the outside Outlet shaft over, so that the Possibility of reflecting particles backwards is sided.

In the aforementioned embodiment, it is useful if the higher leg in the outer section of the Throwing wing parallel to the bottom of the storage container  is arranged. The thigh in the outer section of the litter wing is so high that even such particles be detected at a flat angle to the outside be reflected in an uncontrolled manner.

Another embodiment of the invention stands out characterized in that the web and the upper leg each The throwing wing rest against the cap at its inner end, it is also advantageous if the upper leg on inner end along the entire length of its edge at the Cap fits.

With the aforementioned embodiment, the spreader wing is on its inner end, as it were, closed. This will largely avoided that when entering the throwing wing Particles are reflected in the scattering material beam reflected particles may be caught gene and exposed to the centrifugal field of the throwing wing become.

Preferably, the training is such that the front running edge of the upper leg on one of the system Place the bridge on the cap in the extension of the bridge about the opposite point of the cap, in one first curvature with increasing radial distance from the Axis of the centrifugal disc is pulled forward and with a subsequent opposite curvature in a straight line approximately parallel to the web merges, whereby before geomatically the first curvature of the leading edge is roughly spiral.

In this way, on the one hand, the width of the top Thighs in the area near the center of the centrifugal disc widened, so the spreader wing overall lower, so that more particles can be captured. On the other hand  results from the curvature of the leading edge at their entry into the scattering material jet has an impulsive force the particles that are largely directed outwards. This applies in every rotational position of the throwing wing, so that too hereby the possibility of a reflection of the particles the leading edge that bounce it off inside leaves, is largely excluded.

The cap, which is the lower edge of the Aus tower extends above and ensures that between the lower edge of the outlet shaft and the upper one Thigh particles are not splashed inside, is particularly effective when the radius of the cap is a little smaller than the radius relative to the axis the inside of the centrifugal disc outlet shaft.  

Usually, the centrifugal discs are from below driven by a drive shaft, for example is connected to the PTO via a bevel gear. For this purpose, the drive shaft has a hub which is attached to the slinger. According to the invention now the cap for attaching the centrifugal disc to the hub to serve.

A further preferred embodiment is characterized by this from that the throwing wing at its outer end, from the upper Outgoing leg, sloping downwards.

While the particles are predominant in small quantities move outwards in the lower part of the spreader vane, climb with larger spreading quantities upwards until the spreading wing is occupied over its entire height. With even larger litter quantities build up within the spreader wing certain layer thickness due to the different Acceleration of the particles in the different layers lead to irregularities in the spread pattern. Due to the Ab leave the bevel moving those further up in the spreading wing Particles the spreader wing earlier than the parts moved below kel. This results in practical tests as shown have an even spread pattern even with large ones Spread. The bevel can only extend over part of the Extend height or over the entire height, so that the Particles are released on different radii and thus reach different throwing distances.

Finally, according to an expedient embodiment, the Outlet shaft one down from the outlet opening taking cross-section. This feature serves - similarly like the upper leg set at a clearance angle of the throwing wing - primarily to back up the  Spreading material in the discharge chute as the spreader wing passes to avoid, which above all avoids quantity errors.

The invention is based on one in the drawing reproduced embodiment described. In the Drawing shows:

Fig. 1 is a schematic partial view of a two disc centrifugal spreader;

Fig. 2 is a scatter image diagram;

. Fig. 3 is a view similar to Figure 1 of a first embodiment of the invention;

FIG. 4 shows a top view of the centrifugal discs according to FIG. 3;

FIG. 5 shows the cross sectional profile of the spreading blade;

Figure 6 is a plan view of a centrifugal disc, in a further embodiment.

FIG. 7 shows a representation of a further exemplary embodiment similar to FIG. 1;

Fig. 8 is an enlarged partial view of the centrifugal disc shown in Fig. 7 in the right part and

Fig. 9 is a view corresponding to FIG. 1 of a further embodiment.

The fertilizer spreader shown schematically and in sections in FIG. 1 has a funnel-shaped storage container 1 with a base 2 , outlet openings 3 arranged therein and adjoining outlet ducts 4 which extend downward ver. A stirrer 5 which loosens the fertilizer and keeps it free-flowing is arranged within the storage container 1 . Below the bottom 2 of the reservoir 1 , a centrifugal disc 6 is arranged under each outlet shaft 4 , the axis of rotation of which is offset to the outside relative to the outlet shaft 4 . Each centrifugal disc has at least one, in the exemplary embodiment shown, two throwing vanes 8 which extend outwards from the center of the centrifugal disc. The centrifugal disks 6 and the stirrer 5 are driven, for example, by the power take-off shaft of a tractor via bevel gear transmissions, which are accommodated in the transmission housing 9 , which is shown schematically again.

The centrifugal disks 6 are plate-shaped in the embodiment shown in FIG. 1 with an upwardly rising wall, so that the throwing vanes 8 accordingly run inclined upwards. This training is particularly suitable for large spreading widths in order to achieve favorable ballistics for the fertilizer particles leaving the centrifugal disc 6 .

A typical spread pattern for a certain working width generated by a centrifugal broadcaster according to FIG. 1 is shown in the diagram according to FIG. 2, in which the spread density (weight per area) is plotted against the spread width. Four characteristic scatter patterns for four different scatter quantities a , b , c and d are shown, with a < b < c < d . The ordinate coincides with the longitudinal axis of the tractor or the direction of travel. From Fig. 2 it can be seen that with smaller spreading quantities, the spreading density drops steadily outwards from a maximum behind the tractor. The larger the spread rate, the more pronounced the cant in the tractor axis. From a certain spread rate, a spread pattern is formed, as is shown in Fig. 2 with the help of curve d the largest spread rate. It is no longer a steady curve, rather it has, in addition to the central elevation towards the outside, a depression and then subsequent elevations, from which the scattering density then drops much more steeply. The curve d applies, for example, to a centrifugal disc with two spreader vanes. If, on the other hand, it has four spreader vanes, then the two side elevations are not or less pronounced, but the middle elevation is much more pronounced.

With small and medium spreading quantities, the Compensate for thinning in the outer area by the fact that Connection driving ensures an overlap of the scatter patterns is so that there is only one over the entire sprinkled area weakly wavy scatter pattern results. With larger spreading quantities compensation is only possible in the peripheral areas Lich, however, neither the average cant nor the subsequent sinks and also extremely poor compensate for the two side elevations.

While the mean camber is formed almost exclusively by the so-called baffle effect or through the impingement losses, that is to say by that the fertilizer particles, the wings of the union 8 are not detected in a controlled manner, son countries on the disc itself and the vobeilaufenden the discharge shaft 4 throwing vanes 8 are reflected and are mainly deposited in the middle, the two lateral exaggerations are caused by the so-called volume effect and are primarily attributable to fluid flow processes that cannot be influenced in the spreader vane. With an increasing working width, the impact losses increase due to the necessarily larger volume throughput, as does the volume effect.

Fig. 3 shows a first embodiment of the invention, in which 4 flexible material strips 10 , for example in the form of plastic bristle bundles, are arranged on the outside of the outlet shaft. They run essentially vertically and protrude into the movement path of the throwing vanes 8 . They are, as Fig. 4 shows, arranged at all limits of the outlet shaft 4 , where they can dodge wings when immersed in the grit so that they can not affect the grit. The scattering material beam is thus framed and guided at these limits by the flexible material strips 10 , in particular the particles cannot be reflected forwards and inwards. On the other hand 10 the flexible strip of material in the direction of rotation, as soon as they are detected by the vanes. 8

The spreader vanes 8 are preferably made of a U-shaped profile, ie, as can be seen in FIG. 5, consist of an approximately perpendicular web 11 , a lower leg 12 , by means of which the spreader vanes 8 are fastened to the centrifugal disc 6 , and one upper leg 13 . The upper's angle 13 is advantageously inclined towards the rear from the leading edge 14 , which first enters the scattering material jet, so that a clearance angle is created.

Fig. 6 first shows in the wing shown on the left with dash-dotted lines 13 'a spreader wing which is drawn at its inner end beyond the center of the centrifugal disc to the other side. The leading edge 14 'is attached to the web at the inner end and runs with a curvature 14 "into the rectilinear section which runs approximately parallel to the web.

Fig. 6 also shows with solid lines an optimized embodiment, a cylindrical cap 15 is arranged in which the center of the centrifugal disk 6. The throwing vanes 8 rest with their inner end on the cylindrical outer surface of the cap 15 . For example, the web 11 of the throwing wing 8 ends with its vertical inner edge 16 on the jacket of the cap 15 , while the upper leg 13 is pulled inward beyond this inner edge 16 . The leading edge of the leg 13 starts approximately at a point 17 on the cap 15 , which is an extension of the web 11 . From there, the leading edge runs outward in a spiral curvature 18 . This is followed by an oppositely directed curvature and finally the leading edge 14 merges into a linear section that terminates on the outside.

The radial distance of the inner boundary of the outlet chute 4 is, as shown in FIG. 7, somewhat larger than the radius of the cap 15 . Furthermore, the cap 15 projects beyond the lower edge of the outlet shaft 4 , so that a complete conclusion is given in the center. In the Ausführungsbei of FIG game. 7 can also be seen that the upper's angle 13 is deposited in the outer portion of the throwing blade 8. Details of this can be seen in FIG. 8. The leg 13 has in the area outside the outlet shaft 4 an elevated portion 20 , which is in particular higher than the lower edge of the outlet shaft and in the exemplary embodiment shown is arranged in a plane parallel to the floor 2 . The inner edge 21 of the web 11 formed at the transition lies on a radius that is slightly larger than that of the outer boundary of the outlet shaft 4 . The same design is of course also possible with such slingshots, which are not curved in the manner of plates, but are designed as simple horizontal plates, in which case the upper leg 13 and its outer section 20 lie in parallel planes, which in turn are parallel to the lower one Leg 12 can lie.

Fig. 8 also shows that the throwing wing 78 is chamfered at its outer end from above to the outside, so that the particles accelerated to the outside in the upper region of the throwing wing 8 let the throwing wing ver earlier or on smaller radii than the moving below Particle.

The centrifugal disc 6 is driven by a drive shaft 23 which is provided with a hub 24 . This can have an external thread onto which the cap 15 can be screwed. In this way, by means of the cap 15, the sluice derscheibe 6 braced on a collar 25 of the hub 24 . To take a driver pin 26 is also angeord net on the collar 25 , which passes through the slinger 6 and engages in a groove on the cap 15 .

Finally, the embodiment according to FIG. 9 shows a downcomer 4 , the free cross section of which extends from the outlet opening 3 downwards, so that the throughput is not negatively influenced by backflow effects.

Claims (15)

1. Centrifugal broadcaster for free-flowing grit, in particular special fertilizer, consisting of a storage container with at least one adjustable outlet opening and an adjoining vertical outlet shaft, from which the grit emerges jet-like in the falling stream, and a centrifuge underneath about an offset axis to the outlet disc with at least one spreader vane which extends over the entire radial extent of the spreading material to the circumference of the centrifugal disc and forms a U-profile in cross section, which is fastened to the centrifugal disc with its lower leg, characterized in that the upper leg ( 13 ) of the U-profile of each spreader vane ( 8 ) at least with its leading edge ( 14 ) and in the section running past the outlet shaft ( 4 ) in a plane parallel to the lower edge of the outlet shaft with a short distance below it is arranged and that in the center of the Centrifugal disc ( 6 ) a cylin Drische cap ( 15 ) is arranged, which extends above the nearby lower edge of the outlet shaft ( 4 ) upwards. 2. Centrifugal broadcaster according to claim 1, characterized in that the upper leg ( 13 ) of each Wurfflü gel ( 8 ) from its leading edge ( 14 ) against the direction of rotation is inclined downward to form a clearance angle. 3. Centrifugal broadcaster according to claim 1 or 2, characterized in that the leading edge of the upper leg ( 13 ) of each throwing wing ( 8 ) attaches to the web ( 11 ) at its inner end and in a forward curvature in a straight line, to the web if necessary parallel section merges. 4. Centrifugal broadcaster according to one of claims 1 to 3, characterized in that each throwing blade ( 8 ) with its inner end over the center of the centrifugal disc ( 6 ) extends to the other side. 5. Centrifugal broadcaster according to one of claims 1 to 4, characterized in that the upper leg ( 13 ) of each throwing blade ( 8 ) in its outer section ( 20 ), which - seen from the center of the centrifugal disc ( 6 ) - beyond the outlet shaft ( 4th ) is located higher than the lower edge of the outlet shaft. 6. Centrifugal broadcaster according to one of claims 1 to 5, characterized in that the web ( 11 ) of the U-Pro fils each spreader wing ( 8 ) in its outer cut from with its at the transition to the higher leg ( 20 ) located inside edge ( 21 ) lies on a radius of the centrifugal disc ( 6 ), which is little larger than that of the radially most white outer boundary of the outlet chute ( 4 ). 7. Centrifugal broadcaster according to one of claims 1 to 6, characterized in that the higher leg ( 20 ) is arranged in the outer portion of the throwing wing ( 8 ) parallel to the bottom ( 2 ) of the storage container ( 1 ). 8. Centrifugal broadcaster according to one of claims 1 to 7, characterized in that the web ( 11 ) and the upper leg ( 13 ) of each throwing blade ( 8 ) abut on the inner end ( 16 , 17 ) of the cap ( 15 ). 9. Centrifugal broadcaster according to one of claims 1 to 8, characterized in that the upper leg ( 13 ) bears at the inner end over the entire length of its edge on the cap ( 15 ). 10. Centrifugal broadcaster according to one of claims 1 to 9, characterized in that the leading edge ( 14 ) of the upper leg ( 13 ) at one of the system ( 16 ) of the web ( 11 ) on the cap ( 15 ) in the extension of the Web approximately opposite point of the cap ( 15 ) attaches in a first curvature ( 18 ) with increasing radial distance from the axis ( 7 ) of the centrifugal disc ( 6 ) is pulled forward and with a subsequent opposite curvature ( 19 ) in a Web ( 11 ) passes approximately parallel straight line. 11. centrifugal spreader according to one of claims 1 to 10, characterized in that the first curvature of the leading edge is approximately spiral. 12. Centrifugal broadcaster according to one of claims 1 to 11, characterized in that the radius of the cap ( 15 ) is slightly smaller than the radius of the innermost limit of the outlet shaft ( 4 ) with respect to the axis ( 7 ) of the centrifugal disc ( 6 ) . 13. Centrifugal broadcaster according to one of claims 1 to 12, with a drive shaft arranged below the centrifugal disc, on the hub of which the centrifugal disc is fastened, characterized in that the cap ( 15 ) for fastening the centrifugal disc ( 6 ) on the hub ( 24 ) serves. 14. centrifugal disc according to one of claims 1 to 13, characterized in that the throwing wing ( 8 ) is chamfered downwards at its outer end from the upper leg ( 13 , 20 ). 15. Centrifugal disc according to one of claims 1 to 14, characterized in that the outlet shaft ( 4 ) has a cross-section which increases from the outlet opening ( 3 ) downwards.