GB2130464A

GB2130464A - Soil-cultivating implement

Info

Publication number: GB2130464A
Application number: GB08328992A
Authority: GB
Inventors: Friedhelm Dutzi
Original assignee: RDZ DUTZI GmbH
Current assignee: RDZ DUTZI GmbH
Priority date: 1982-10-29
Filing date: 1983-10-31
Publication date: 1984-06-06
Also published as: FR2535150A1; DE3240169A1; FR2535150B1; GB8328992D0; GB2130464B

Abstract

In a soil-cultivating implement for introducing materials, in particular powdered materials, into the soil, for example for depth fertilizing, the materials are conveyed by means of a metering device 8a Fig. 2 into a mixing chamber 11a, where they are mixed with compressed air blown in and are then further passed on to an injection nozzle as a two-phase flow. This injection nozzle is mounted on a blade 3 parting the soil horizontally and is in the form of a fan-shaped nozzle. <IMAGE>

Description

SPECIFICATION Soil-cultivating implement The invention relates to a soil-cultivating implement comprising a frame either adapted to be coupled to a tractor or having its own drive, with at least one blade which, in use, parts the soil horizontally at an adjustable depth and lifts it towards the rear, whose cutting faces, diverging obliquely towards the rear symmetrically to the longitudinal axis, are joined together by way of a common covering, at least one injection nozzle, connected to a storage container by way of conveying line and in which material is, in use, conveyed to the nozzle by compressed air, being disposed below the covering in order to introduce the material, in particular fertilizer, into the ground.

An soil-cultivating implement of this type is known from the Dutch Patent Application 7400416. Here the storage container is filled with liquid material and its upper part is connected to a pressure tank. This pressure tank exerts a constant pressure on the liquid to be sprayed and forces it through the conveying line to the injection nozzle and from there into the broken up layer of soil.

Investigations by the Applicants have shown that this known implement is suitable in practice only for liquid or gaseous materials. On the other hand, in the case of powdered material, in particular granulates, obstructions occur very quickly in the conveying line, as the flow resistance in solids is considerably higher and these substances also tend to form agglomerates and to stick together between themselves.

In addition, the effective width of the material discharged from the injection nozzle is very small as it affects only the area of the soil in the direction of the nozzle, while at the edges of the blade scarcely any material reaches the soil.

It is believed possible by means of the present invention to provide an implement suitable for powdered materials, in particular for granulates, such that a substantially homogenous distribution of the material in the soil can be ensured.

According to the invention the storage container comprises a metering device for control ling the quantity of the material, and there is connected to the said metering device a mix ing chamber in which the metered quantity of material is mixed with compressed air and is conveyed to the injection nozzle as a two phase flow.

In a preferred embodiment of the invention, the material is not acted upon with com pressed air, but is intensively mixed with it.

The material is conveyed into the mixing chamber through a metering device, in order that the proportion of material in the twophase mixture formed in the mixing chamber is not too high and no massing together and obstructions need be feared. On the one hand the compressed air discharged with the material from the injection nozzle improves the horizontal distribution of the material in terms of width and on the other hand an intensive aeration of the broken-up clods of soil earth takes place as a favourable side effect.

In particular, the implement embodying the invention allows phosphate, which is generally found in the form of granulates of from 3 to 4 mm, to be introduced without difficulty into the layers of soil intended for the depth fertilizing. In the same way styropore particles for loosening and aerating solid soils and any other materials, such as insecticides, may be introduced into the soil. In the case of all these substances the high proportion of compressed air ensures good distribution transversely to the direction of travel and thus a homogenous treatment result.

In order to supply the quantity of material always in the correct dosage, even under variable operating conditions, it is particularly recommended that the material quantity control of the metering device should be dependent upon the velocity of travel. In this way the desired quantity of material per hectar is always suppled irrespective of the travel velocity. This regulation of quantity may advantageously be achieved by the metering device being driven by a wheel rolling along the ground.

Concerning the structural design of the metering device, various possibilities are open to the person skilled in the art. It has been found to be particularly advantageous to use a conveying screw for this, the throughput of which is approximately proportional to the rotational speed.

In order to ensure an intimate mixing with the compressed air in the mixing chamber, it is advantageously designed in accordance with the principle of the Venturi nozzle, i.e. a converging nozzle, through which the com pressed air passes axially and in the vicinity of whose outlet opening the socket of the metering device opens, is disposed in the mixing chamber. The material is sucked out of the metering device by the drop pressure in the air flow occurring downstream the nozzle and by virtue of its inflow orientated transversely with respect to the air flow it is subjected to intensive turbulence and mixing.

In order to produce the compressed air it is recommended not to use a stationary com pressed air container as in the case of the known implement, but a blower. This blower is designed in such a way that the conveyed volume of compressed air is many times greater than the volume of material in the mixture. The blower may be driven by the tractor. It may be dependent upon the velo city, but it need not be, since the changes in the quantity of the material relative to the considerably higher volume of air are not important.

Finally, in a further development of the invention it is recommended that a base plate should be mounted on the blade below the injection nozzle and vertical sheet metal guides, which diverge from the injection nozzle, should be interposed between the base plate and the covering. In addition, the injection nozzle may be in the form of a fanshaped nozzle with a plurality of openings orientated in divergent directions, so that the mixture of material and compressed air discharged from the nozzle may be distributed as far as the outermost areas of the blade.

The invention will be described by way of example with reference to the drawings. In this example the implement embodying the invention is combined with further soil-cultivating implements known per se. In the drawings: Figure 1 is a side view of a soil-cultivating implement embodying the invention; Figure 2 is a front view of the same implement; Figure 3 is an enlarged detail of a mixing chamber in the implement; Figure 4 is a partially cut away side view of a blade of the implement; Figure 5 is a rear view of the said blade, and Figure 6 is the view of the blade from above, but with a covering removed.

As Figs. 1 and 2 show, the soil-cultivating implement comprises a frame 1, on which all the essential driving parts and operating tools are mounted and which is attached to a tractor by the usual three-point support 2. On the front of the implement are mounted a plurality of blades 3a, 3b and 3c parting the soil horizontally with cutting surfaces diverging obliquely towards the rear, and behind them a pronged rotor 4 illustrated in dash-dot lines with the prongs penetrating into the surface of the soil, and at the end of the implement a clod packer roller 5 which is likewise illustrated in dash-dot lines and which supports the implement at the same time.

Three storage containers 6a, 6b and 6c, which are each associated with a blade 3a, 3b and 3c respectively, are mounted above the frame 1. One common storage container could alternatively of course be used for all the blades. The storage containers are mounted in each case on a bracket 7 rigid with the frame. Discharging screws 8a, 8b and 8c respectively, which are driven by a common through shaft 9, are disposed in the funnel-shaped base area of the storage containers. They convey the material contained in the storage containers in metered quantities to a delivery socket or aperture 1 Oa, 1 Ob and 1 Oc respectively, which opens into a mixing chamber 1 lea, 1 ib and 1 1c respectively. A compressed air line also opens into each mixing chamber; one of the said compressed air lines, 1 2a, is visible in Fig. 1.The mixing chamber itself is subsequently described in greater detail in connection with Fig. 3.

As shown in particular by Fig. 1, a blower 1 4 is flange-mounted on a gear transmission 1 3 for driving the pronged rotor 4. A distributor container 15, from which three brances (the branch 12a is visible in Fig. 1) lead to the mixing chambers 11 a, 11 b and 11 c, is mounted on the air outlet of the blower 1 4.

The mixing chambers are preferably designed in accordance with the principle of Venturi nozzles. One embodiment is illustrated on an enlarged scale in Fig. 3. According to this, the compressed air arriving from the blower 1 4 [and passing through a converging nozzle 1 6 at the entry to the mixing chamber undergoes a constriction in crosssection and a corresponding increase in velocity. The delivery socket or aperture of the respective storage container, i.e. the delivery socket 1 0a for example, opens into the region of the nozzle opening, preferably at right angles to the compressed air flow. The mixing chamber delivery nozzle 17, the cross-section of which is greater than the outlet crosssection of the nozzle 16, is arranged in an extension of or in line with the nozzle 1 6 and axially spaced therefrom.

The mode of the operation is as follows: on account of the increase in velocity occuring at the end of the nozzle 1 6 there is considerable reduction of the static pressure in the mixing chamber. The result of this is that material is sucked out of the delivery socket 1 Oa of the storage container and is intimately mixed with the compressed air on account of its inflow in the transverse direction. The suction effect in conjunction with the metered material delivery from the metering device in the form of the discharging screw and finally the turbulence and mixing of both phases which take place in the mixing chamber ensure that even powdered materials tending to agglomerate may be reliably conveyed.

The continuation of the two-phase flow formed in the mixing chamber is again visible in Figs. 1 and 2. A respective conveying line 1 8a, 1 8b and 1 8c, which leads downwards to the blade 3a, 3b and 3c respectively, is connected to each mixing chamber. It opens into an injection nozzle, into the injection nozzle 1 9a in the case of the blade 3a illustrated in Figs. 4 to 6. The said injection nozzle is disposed in each case in the angle between the two cutting faces 3a' and 3a" and is in the form of a divergent nozzle with an outlet cross-section open towards the rear.

It is covered at the top by a covering 20a joining the two cutting faces 3a' and 3a" and at the bottom by a base plate 21 a parallel thereto. A plurality of sheet metal guides 22a extending radially outwards from the injection nozzle 1 9a are disposed between the covering and the base plate. They ensure a fan-shaped distribution of the air/material mixture blown out of the injection nozzle 1 9a.

The operation of the soil cultivating implement embodying the invention is as follows: The material, preferably phosphate granulates intended for depth fertilizing, contained in the storage containers 6a, 6b and 6c is conveyed through the build-in discharging screws 8a, 8b and Sc in a specified continuous mass flow to the outlet sockets 1 Oa, lOb and 1 Oc.

In order that the metering may conform to the travel velocity of the implement, the shaft 9 connecting the discharging screws is driven by way of a wheel 23 rolling over the ground.

This wheel is connected to the shaft 9 by way of a gearing and V-belt. However, a different drive dependent on the travel velocity may also, of course, be selected for controlling the mass.

The blower 14 flange-mounted on the gear transmission 1 3 is driven by the rear power take-off of the tractor and conveys compressed air at a volume flow which is many times greater than the volume flow of the material arriving from the metering device.

This compressed air is blown axially through the mixing chambers 11 a, 11 b and 11 c and entrains with internal turbulence and mixing the material mass arriving from the metering device. On account of the two-phase flow this mixing is conveyed without the risk of obstruction at high velocity through the conveying lines 1 spa, 1 8b and 1 sic to the injection nozzles in the blades 3a, 3b and 3c and from there is blown into the broken-up layer of soil.

In this way an optimum depth fertilizing with a good spreading effect is possible, in which the adjacent injection nozzles cover an almost horizontally continuous homogenous layer of soil. On account of these properties the implement is also of course suitable for introducing other substances in lower-lying layers of soil.

Claims

1. A soil-cultivating implement comprising a frame either adapted to be coupled to a tractor or having its own drive, with at least one blade which, in use, parts the soil horizontally at an adjustable depth and lifts it towards the rear, whose cutting faces, diverging obliquely towards the rear symmetrically to the longitudinal axis, are joined together by way of a common covering, at least one injection nozzle, connected to a storage container by way of a conveying line and in which material is in use, conveyed to the nozzle by compressed air, being disposed below the covering in order to introduce the material into the ground, characterized in that the storage container comprises a metering device for controlling the quantity of the material, and in that there is connected to the metering device a mixing chamber in which the metered quantity of material is mixed with compressed air and is conveyed to the injection nozzle as a two-phase flow.

2. A soil cultivating implement according to Ciaim 1, characterized in that the material quantity control of the metering device is dependent upon the velocity of travel.

3. A soil-cultivating implement according to Claim 2, characterized in that the metering device is driven by a wheel rolling along the ground.

4. A soil-cultivating implement according to any one of the preceding Claims, characterized in that the metering device is in the form of a rotating discharging screw.

5. A soil-cultivating implement according to any one of the preceding Claims, characterized in that the mixing chamber contains a converging nozzle through which the compressed air passed and in that a socket of the metering device opens in the outlet region of the said nozzle.

6. A soil-cultivating implement according to any one of the preceding Claims, characterized in that the mixing chamber is connected to a blower.

7. A soil-cultivating implement according to any one of the preceding Claims, characterized in that the volume of air conveyed to the mixing chamber is, in use, many times greater than the volume of material.

8. A soil-cultivating implement according to any one of the preceding Claims, characterized in that a base plate is mounted on the blade below the injection nozzle and in that sheet metal guides, which diverge from the injection nozzle, are interposed between the base plate and the covering.

9. A soil-cultivating implement according to any one of the preceding Claims, characterized in that the injection nozzle is in the form of a fan-shaped nozzle with a plurality of openings orientated in divergent directions.

10. A soil-cultivating implement according to any one of the preceding Claims, characterized in that the blade is combined with a blade parting the soil vertically, with a driveable pronged rotor disposed behind them and a clod packer roller disposed in the rear.