EP1605750A2

EP1605750A2 - Crop-protective spraying device

Info

Publication number: EP1605750A2
Application number: EP04721897A
Authority: EP
Inventors: Wolf-Dieter Wichmann
Original assignee: Lechler GmbH
Current assignee: Lechler GmbH
Priority date: 2003-03-22
Filing date: 2004-03-19
Publication date: 2005-12-21
Also published as: WO2004082845A2; DE10312930A1; WO2004082845A3

Abstract

The invention relates to a crop-protective spraying device in which the wash container is used only as a reservoir (27) for clean water and for discharging liquid fertilizer without the active substances being added to the water in the wash container. According to the invention, the active substances, several of which can be used at the same time, are added to the water in the intake area of the wash pump (31), wherefore metering pumps (10) are used which are derived from star wheel-type pumps and whose output rate is adjustable.

Description

Pflanzenschutzspritzvorrichtunq

The invention relates to a crop protection spraying device for the direct metering of active substances into a carrier liquid during the spraying with a storage container, a broth pump for conveying the carrier liquid from the storage container to at least one spray nozzle along at least one supply line, an active substance container and at least one metering pump for Mixing active substances from the active substance container into the at least one supply line.

In the case of crop protection sprayers, it has long been known to carry out the mixing of water and active ingredients in the broth container with the aid of flushing mechanisms before the start of the spraying work. Since the amount of spray liquor required for a treatment can only be roughly determined, more spray liquor is usually mixed than is ultimately consumed. The resulting residual quantities must be diluted to ineffectiveness and applied in the field. As a result, water, active ingredient and working time are wasted and the area is unnecessarily burdened. Is for weather reasons or technical If it is necessary to interrupt spraying, the mixed spray mixture remains in the spray tank. Due to possible leaks, this always harbors risks for the environment and may have an adverse effect on the effects of the chemicals. Since the entire broth container and the majority of all fittings and pipes are contaminated with the active ingredients during the spraying process and often on the way to the field, any damage to the sprayer that may occur and damage to the environment cannot be calculated.

Furthermore, crop protection spraying devices are known in which the active ingredients are only admixed during the spraying of a carrier liquid.

For example, a crop protection spraying device is known from US Pat. No. 3,481,540, in which active ingredient from an active ingredient container is only mixed with a plurality of spray nozzles immediately before it flows into a fuel bar. Only water is carried in a storage container, which is conveyed to the spray bar by means of a main pump. The active ingredients are fed in directly in front of the spray bar by means of a metering pump. A constant ratio during a fueling process between the delivery volume of the main pump and the delivery volume of the metering pump is ensured by means of a common drive between the main pump and the metering pump. For this purpose, the main pump and the metering pump are driven by a common shaft, which can be connected to a PTO shaft of a tractor. In order to be able to adjust the ratio of active substances to carrier liquid, an adjustable gear is provided between the common shaft and the metering pump. The metering pumps are designed as piston pumps.

From the German patent DE 39 08 963 C2 a crop protection spraying device is known, with the active ingredients only during the Spraying can be introduced into a carrier liquid. For this purpose, metering pumps are arranged in the area of the branching to the individual partial areas of the spraying device. The metering pumps are designed as reciprocating piston pumps which deliver a constant amount of active ingredient into the carrier liquid per stroke. A ratio between active substance and carrier liquid is set by changing the control frequency of the metering pumps. The metering pumps are controlled by means of an electronic control which, among other things, receives input signals from a flow meter which detects the amount of carrier liquid flowing in the supply line.

Another crop protection spraying device is known from German published patent application DE 199 04 102 A1, in which active ingredients are only introduced into a carrier liquid during spraying. A carrier liquid is conveyed by means of a main pump and several dosing pumps for different active substances are connected to a supply line downstream of the main pump. To control the dosing pumps, an electronic control unit is provided, which receives input signals from a flow transmitter downstream of the last dosing pump. In addition, a ratio control for the ratio between active substance and carrier liquid is provided, which is implemented by activating the metering pumps as a function of the total volume carried through the supply line. The relationships between active substance and carrier liquid are specified by a database.

The aim of the invention is to provide a crop protection spraying device which enables direct metering of active ingredients with a simple, reliable structure and high precision. According to the invention, this is a crop protection spraying device for direct dosing of active substances into a carrier liquid during spraying with a storage container, a broth pump for conveying the carrier liquid from the storage container to at least one spray nozzle along at least one supply line, at least one active substance container and at least one metering pump for mixing active substances the active substance container is provided in the at least one supply line, in which the at least one metering pump for admixing the active substance is connected to the supply line upstream of the broth pump.

Due to such an arrangement in the line system of the crop protection spraying device, the metering pumps have to deliver almost no pressure, so that very simple and reliable metering pumps, for example cellular wheel pumps, can be used. Since the metering pumps only have to deliver a very low pressure, adjustable metering pumps with a simple structure can be used in their delivery quantity per stroke or revolution, and nevertheless a high precision of the mixing ratio can be achieved. For example, adjustable rotary pumps can be used.

In a development of the invention, the at least one metering pump and the broth pump can be driven coupled by means of a common drive.

In this way, a constant ratio of the conveyed carrier liquid and the promoted active ingredients is ensured. Since the active ingredients are added to the suction channel of the broth pump by means of the metering pumps, a high precision of the relationship between active ingredient and carrier liquid can be achieved by means of the common drive of the broth pump and metering pump, without superimposed control mechanisms having to be provided. The ratio of active ingredient to Carrier liquid is defined by setting the delivery quantity of the dosing pump per stroke or revolution and then maintained by the common drive ratio of the broth pump and dosing pump for the delivery rate ratio of the broth pump and dosing pump.

In a further development of the invention, the spray pressure is regulated by regulating the delivery rate of the broth pump.

For example, the spray pressure is regulated by regulating the drive speed of a hydraulically driven broth pump. As a result, there is no need for an overpressure return line, which is provided in conventional field sprayers and which flows back into the broth container. Returned quantities of mixed spray liquid do not occur in spraying operation. The drive speed of a hydraulically driven broth pump is regulated, for example, by actuating a hydraulic valve which assigns the oil quantity to the hydraulic motor. An actual value can be specified using a flow meter or pressure meter provided downstream of the broth pump.

In a development of the invention, the broth pump and the at least one metering pump are arranged on a central part of the rod of the crop protection spraying device.

In this way, short distances from the metering pumps to the individual spray nozzles can be implemented and the broth pump and metering pumps can be implemented as a compact pump and drive unit. The active substance containers are then expediently also in the immediate vicinity of the pump and drive unit on the central part of the rod. The problem underlying the invention is also solved by a crop protection sprayer for direct dosing of active substances into a carrier liquid during spraying with a storage container, a broth pump for conveying the carrier liquid from the storage container along a supply line to at least one spray nozzle, at least one active substance container and at least one metering pump for admixing active substances from the active substance container into the at least one supply line between the storage container and the spray nozzle, in which a dilution container and at least one return line which can be shut off by means of a shut-off valve are provided, the return line branching off from the supply line in the region of the spray nozzles and into the dilution container empties.

By providing the dilution container and the return line, it is possible to advance the spray liquor containing the active ingredient up to immediately before the spray nozzles and also to carry out a rinsing operation without having to accept contamination of the carrier liquid in the storage container. Pre-delivery takes place in such a way that carrier liquid is provided with active ingredient by means of the metering pumps, is conveyed by the broth pump through the supply line to the spray nozzles and via the return line into the dilution container. As a result, the spray liquor does not get into the storage container during prefeeding, but only into the dilution container. In the same way, after the metering pumps have been switched off, the device can be rinsed by conveying pure carrier liquid via the supply line, to the spray nozzles and via the return line into the dilution container. Carrier liquid contaminated with active substance then only reaches the dilution container in the rinsing mode, but not the storage container for the carrier liquid. During the pre-delivery, a pre-delivery time can be set so that only slightly contaminated carrier liquid enters the dilution container reached by stopping the pre-delivery if, after a time to be determined by experiment, it can be assumed that broth has reached the spray nozzles with the correct proportions of carrier liquid and active ingredient. In the rinsing mode, only weakly contaminated carrier liquid gets into the dilution container anyway. The dilution tank can also be filled with carrier liquid to achieve further dilution.

In a further development of the invention, the dilution container can be connected to the supply line.

In this way, the content of the dilution container can be applied via the spray nozzles, for example after pre-conveying, the content of the dilution container either being diluted to ineffectiveness before it is connected to the supply line, or the contents of the dilution container being mixed takes place that there is an ineffective dilution together with the carrier liquid.

In a further development of the invention, the dilution container is permanently in flow connection with the storage container.

In this way, for example, the same liquid levels can be achieved in the storage container and dilution container, for example in order to automatically refill carrier liquid into the dilution container.

In a further development of the invention, a check valve is provided between the dilution container and the storage container, which prevents flow from the dilution container to the storage container. Contamination of the carrier liquid in the storage container can be prevented by such a check valve, although there is a permanent flow connection between the storage container and the dilution container.

In a further development of the invention, a jet pipe connected to the storage container opens into the dilution tank, the jet pipe being guided up to directly in front of a suction connection of the dilution tank connected to the broth pump.

The carrier liquid flowing in from the storage container, for example water, is thus led through the jet pipe right up to the suction connection, corresponding to the outlet connection of the dilution container, which leads to the broth pump, so that only a small amount of turbulence when flowing through the dilution container Amounts of the contaminated content of the dilution container are entrained. This results in a further considerable dilution of the content of the dilution container. The content of the dilution container is thereby distributed once again over the entire amount of the carrier liquid flowing through, especially water, from the storage container. The provision of a jet pipe, which opens into the dilution container directly in front of a suction connection of the dilution container, allows the contents of the dilution container to be mixed in in the desired ratio, without moving parts, for example pumps, valves or the like, having to be provided.

In a further development of the invention, means are provided to mix the content of the dilution container into the supply line during the spraying in such a ratio that the content of the dilution container reaches the supply line diluted to ineffectiveness. In a further development of the invention, a pressure accumulator is provided in the supply line between the broth pump and the spray nozzles.

Such a pressure accumulator can ensure that a satisfactory spray pattern is present immediately after the spray nozzles are switched on. This means that the spraying process can be started before the broth pump starts up, and a possible time delay until the pressure builds up through the broth pump does not have a negative effect on the spray pattern.

In a further development of the invention, the pressure accumulator is designed as a tubular pressure accumulator with an elastic hose component in a housing, the hose component being able to expand within the housing.

Such a design of a pressure accumulator has the advantage that the hose component that comes into contact with the active substance can be completely cleaned in the rinsing mode. This is not readily possible with conventional pressure accumulators with bubble-shaped pressure accumulators. Due to the comparatively low pressure in the supply line and in the pressure accumulator of a maximum of 10 bar, the housing of the pressure accumulator can consist of light plastic material.

Further features and advantages of the invention result from the claims and the following description of a preferred embodiment of the invention in connection with the drawings. The drawings show:

1 shows a sectional view of a metering pump for a crop protection spraying device according to the invention in a first state, 2 shows the metering pump of FIG. 1 in a second state,

3 is a perspective view of the crop protection spraying device according to the invention,

4 is a perspective view of a pump and drive block of the crop protection spraying device of FIG. 3,

5 shows a schematic representation of the overall system of the crop protection spraying device according to the invention and

Fig. 6 is a sectional view of a dilution container of the crop protection spraying device according to the invention.

In the plant protection device according to the invention, the active substance or substances are only metered into the carrier, usually water, directly during the spraying process. It is possible to advance the active ingredient concentration to the nozzles before the start of spraying. Only pure water is carried in the reservoir. An exception is the continued application of liquid fertilizer.

In the crop protection spraying device according to the invention, cellular wheel pumps are used as metering pumps, as shown in FIG. 1, and which are connected to the carrier medium pump or broth pump via a common drive. However, these cellular wheel pumps are designed so that the delivery capacity of the cellular wheel can be adjusted. A state with a changed delivery capacity compared to the illustration in FIG. 1 is shown in FIG. 2. The cell wheel pumps or metering pumps have to deliver a liquid quantity of approx. 0.07 l / min to approx. 2.8 l / min due to the usual concentration ratios in crop protection and due to the arrangement in the System to deliver almost no pressure. This makes it possible to use such cellular wheel pumps as metering pumps for the crop protection spraying device according to the invention. Dosing can be done by changing the delivery volume of the cellular wheel pump so that changes in the drive speed due to the coupled drive have no effect on the dosing ratio. The delivery volume of the cellular wheel pumps can be changed by specifically pivoting a pump housing between two side plates, regardless of the drive speed.

As shown in FIG. 3, a broth pump and several metering pumps are combined to form a compact assembly. As a result, several active ingredients can be metered in simultaneously with different dosage ratios. A commercial tandem gear pump is used as the broth pump in this drive variant. The larger gear pump is driven by the smaller gear pump configured as a hydraulic motor. The use of a gear pump has the advantage that no sensitive valves and diaphragms are necessary. Due to the elimination of the stirrer capacities and technical reflux quantities required in the conventional sprayers, a lower delivery capacity (1601 / min) is sufficient and enables the use of such gear pumps. Due to the relatively low pressure required of a maximum of 10 bar, special, lighter gear pumps can be designed with a higher delivery capacity. It is of course also possible, without restricting the function of the crop protection spraying device according to the invention, to use pumps other than gear pumps, which then have to be adapted for the intended use.

In contrast to the current state of the art, the spray pressure is regulated by regulating the drive speed of the hydraulically driven spray pump. For this purpose, specialist existing hydraulic and electronic components are used. The control takes place via a conventional spray computer, which, in deviation from the current state of the art, controls a hydraulic valve which assigns the oil quantity to the hydraulic motor. The actual value is still specified using a standard flow rate meter between the broth pump and the supply line. The spray nozzles are switched in the usual way by means of a pneumatic individual nozzle switch, optionally grouped together according to sections.

In the crop protection spraying device according to the invention, the drive of the broth pump and the metering pumps is coupled, as can be seen in FIG. 4. As a result, the broth pump and the metering pumps deliver in the same ratio at every possible speed. This ratio and thus the concentration of the active ingredient in the carrier liquid is determined by specifying the delivery rate per revolution for the metering pumps, taking into account that the delivery rate of the broth pump per revolution is always the same. The spatially separate construction of the metering pumps and the broth pump when the drive is common is also possible. In the drive of the dosing pumps from the broth pump there is an electrically switched coupling, e.g. a wrap spring clutch is provided so that all or even individual metering pumps can be switched on and off during the spraying operation.

The structure of the metering pumps will be explained below with reference to FIGS. 1, 2 and 4.

As shown in FIG. 1, a metering pump 10 has an approximately ring-shaped housing 11 with an intake duct 12 and a pressure duct 13, which are each provided with hose connections. The annular housing 11 is about a pivot axis 14 relative to one Pump base 15 pivotable. In a centered position, as shown in FIG. 1, the pump does not deliver despite the speed. This makes it possible to set very low flow rates.

Each metering pump 10 has a cellular wheel 19, which is arranged in the housing 11, which has a circular cylindrical central recess in which the cellular wheel 16 is arranged. A relative position of the housing 11 relative to the base 15 can be set by means of a knurled screw 17, which is attached to a stop 18 of the base 15. The base 15 forms a side plate on which the housing 1 1 is placed. An opposite side plate can then be, for example, a further base for a further metering pump, so that overall a very compact metering pump battery can be built up. A sealing ring 19 is arranged between the housing 11 and a respective side plate.

The side plates are clamped together with tie rods. In the metering pump battery of FIG. 4, several side plates, formed by the respective base 15 of a metering pump, are clamped together by means of tie rods 20. In this way it is possible to mount a plurality of metering pumps 10 on a common drive shaft. To produce suitable fits, spacer sleeves 21 and spacer bodies 22 are provided, which can also form part of a base 1.8, for example. A delivery rate of the metering pumps can be influenced by the selection of the height of the cell wheels 16, that is to say perpendicular to the plane of the drawing in FIG. 1. In the position shown in FIG. 1, the metering pump does not deliver.

2 shows a delivery position of the metering pump, in which the housing 11 is deflected relative to the axis of the cellular wheel 16, so that when the cellular wheel 16 rotates, it is conveyed from the suction channel 12 into the pressure channel 13. As in Fig. 2 too can be seen, the housing 11 is deflected by adjusting the knurled screw 17.

In addition to this manual setting of the delivery volume of the metering pumps, as can be seen in FIG. 4, the housing 11 can also be adjusted by means of a cam 25 and an electric linear drive 26. As a result, an active ingredient concentration can also be changed during the spraying process.

3 shows a crop protection spraying device according to the invention in the form of a field sprayer mounted on a trailer. A reservoir 27 and a dilution tank 28 are mounted on a chassis of the trailer. A compact pump and drive unit 30 consists of a broth pump 31 and a plurality of metering pumps 10 which are driven by a common drive. A total of four reservoirs 32 for active substances are arranged above the pump and drive unit 30, each reservoir 32 being assigned to one of the metering pumps 10 in the pump and drive unit 30. As will be explained with reference to FIG. 5, the preliminary containers 32 are filled from large containers, which are also arranged, for example, on the trailer chassis.

The pump and drive unit 30 and the preliminary container 32 are arranged on a middle part of a boom of the field sprayer, so that short supply lines to the individual spray nozzles can be realized on the linkage.

4, the pump and drive unit 30 of FIG. 3 is shown in more detail. The broth pump and several dosing pumps are combined into a compact assembly. The broth pump 31 is constructed as a tandem gear pump, with a larger gear pump 33 for conveying spray liquor from one smaller, as a hydraulic motor-configured gear pump 34 is driven.

The spray pressure is regulated by regulating the drive speed of the gear pump 33. Conventional hydraulic and electronic components can be used for this. The control takes place via a - not shown - spray computer, which controls a hydraulic valve, which in turn assigns the gear pump 34 a certain amount of oil. The actual value is specified via a flow meter 36 shown in FIG. 5. As can be seen in FIG. 4, the broth pump 31 is coupled to the gear pumps 33 and 34 and the metering pumps 10 by means of a toothed belt 37. This coupled drive of the broth pump 31 and metering pumps 10 always promotes a constant ratio of active ingredient and carrier liquid. 4 shows a total of four metering pumps 10, which are mounted one above the other and form a metering pump battery. All metering pumps are driven by means of a common shaft, which in turn is driven via the toothed belt and ultimately via the gear pump 34. On the drive wheel 38 of the metering pump battery, a wrap spring clutch is provided, which separates the drive connection between

Broth pump 31 and metering pumps 10 and thus a switching off of the active ingredient metering while the broth pump 31 is running. If the metering pumps 10 are switched off as a result, the entire system can be rinsed with water from the reservoir 27 up to the delivery connection of the metering pumps 10 and the rinsing liquid can then be dispensed via the spray nozzles.

5 shows a schematic representation of the overall system. In the plant protection spraying device according to the invention, broth can be conveyed to the spray nozzles without having to return broth to the reservoir 27, as in conventional spraying devices. In the crop protection spraying device according to the invention, the dilution container 28 is used, which is arranged between the storage container 27 and the broth pump 31. This dilution container 28 holds 200 liters and is the same height as the storage container 27 and also arranged at the same height. A non-return valve 40 or a non-return valve between the storage container 27 and the dilution container 28 prevents backflow from the dilution container 28 into the storage container 27. When the storage container 27 is filled with water, the dilution container 28 fills almost to the same level. During the pre-conveying, a time, to be determined in the experiment, is conveyed into this dilution container 28 until, taking sufficient safety into account, the active substance concentration has reached all spray nozzles 41. The contents of the dilution container 28 become contaminated with the active substances.

6, the dilution tank 28 is shown in more detail. The introduced broth is evenly distributed over the entire container height via a distribution pipe 42. The capacity of the dilution container 28 is completely sufficient when fully filled to dilute the active ingredients to ineffectiveness. When spraying, the broth pump 31 sucks from the suction connection 43 of the dilution container 28. The amount of water flowing in from the storage container 27 is guided through the jet pipe 44 to directly in front of this suction connection 43, so that the now considerably reduced turbulence when flowing through the dilution container 28 only small amounts of the contaminated content are carried away. This results in a further considerable dilution, even when the initial filling level of the storage container 27 is only low. The mixing in of the contaminated already Significantly prediluted content now occurs due to the lowering of the liquid level 45 in the dilution tank 28. Its content is thus distributed once again over the total amount of water flowing through from the storage tank 27. For access and cleaning, a cover 46 is provided, in which a ventilation opening 47 is integrated.

The pre-delivery is completely independent of the pressure control system. The pre-delivery is started by pressing a button in the syringe operating terminal. A hydraulic valve is opened together with the flushing valves of the section sections 5.13, which is installed parallel to the hydraulic control valve of the speed control for the broth pump. Between this hydraulic valve and the hydraulic motor there is a hydraulic throttle with which the optimum speed of the pumps for the pre-delivery is set by the manufacturer. When this valve opens, the hydraulic motor 34 begins to rotate, the broth pump 31 and the metering pumps 10 begin to feed into the dilution tank 28 via a return ring line 49.

When the button is pressed, a timer is activated which closes the rinsing valve 48 after an optimal time determined in the experiment ∑u. The pumps continue to feed into a tube pressure accumulator 50. A pressure transmitter is installed in the nozzle tubes, which interrupts the holding circuit of the hydraulic valve when the pressure of approximately 6 bar is reached. The oil flow is interrupted and the pumps stop. Both the desired spray liquid concentration and a slightly higher than the desired spray pressure are now present at the nozzles. A check valve 51 prevents backflow to the broth pump. This method compensates for the delay to be expected when the syringe is switched on and thus the pressure control until the required pump speed is reached from the volume of the tube pressure accumulator. The tube pressure accumulator 50 is a special variant of a gas pressure accumulator. A rubber hose 52 contained in a housing expands against the gas admission pressure in the tubular housing 54 until it rests against the inner walls of the housing 54. In contrast to known systems, a rubber hose is used and not a rubber bladder. This is in order to enable flushing of the tubular pressure accumulator 50 from the inside, which is possible due to the use of a rubber hose. Due to the low pressure level of a maximum of 10 bar in the crop protection spray device according to the invention, in contrast to the hydraulic area, the housing 54 of the tubular pressure accumulator 50 can be made of light plastic material.

The suction hoses of the metering pumps are connected to the outlet openings of the preliminary container 32 with self-closing quick-action couplings, a male part being arranged on the preliminary container 32 and a female part being arranged on the suction hose. When the active substance is changed or when the spray ends, these suction hoses are detached from the preliminary containers 32 and coupled to a flushing station 56. During a flushing run, water is sucked out of the storage container 27 via the flushing station 56 and the metering pumps 10 can thus be flushed. It is possible to calibrate the delivery rates.

The dosing pumps 10 are supplied via the preliminary containers 32, which are sealed airtight after an initial filling with active substance. The reservoirs 32 are dimensionally stable and are placed directly above the metering pump 10. The reservoirs 32 can be connected to large containers 57 by hoses. The reservoir 32 with the metering pumps 10 and the coupled broth pump are arranged, for example, on a central part of the rod. The large containers 57 can then in turn be placed on a towing vehicle or in the front part of a field sprayer. If the metering pumps 10 deliver active substance from the reservoirs 32 during the spraying, it drops the liquid level in the reservoirs 32 decreases, which in turn creates a negative pressure above the liquid level in the reservoirs 32. This negative pressure which arises during the removal is used to request the active substances from the large containers 57. The weight of the active ingredients in the reservoirs 32 reduces the vacuum required for this to be applied by the metering pumps 10.

The mode of operation of the crop protection spraying device according to the invention will be explained in more detail below with reference to the schematic overview in FIG. 5. The crop protection spraying device according to the invention has the reservoir 27 for carrier liquid, usually water. The storage container 27 is in flow connection with the dilution container 28, which is the same height as the storage container 27 and is connected to the storage container 27 via a connecting line. The check valve 40 is installed in the connecting line ∑ between the dilution container 28 and the storage container 27 and prevents a backflow from the dilution container 28 into the storage container 27. When filling the storage container 27, the dilution container 28 is filled essentially to the same liquid level. The dilution container 28 has a smaller capacity than the storage container 27, for example 200 liters. Liquid from the dilution tank 28 and the storage tank 27 is conveyed to the individual spray nozzles 41 by means of the broth pump 31 via a supply line. The spray nozzles 41 are arranged in several sections, with the supply line branching into individual lines to the respective sections in a distributor area 58. In the supply line between the broth pump 31 and the distributor area 58, the flow rate meter and / or pressure meter 36, the check valve 51 and the tube pressure accumulator 10 are switched on one after the other in the flow direction. tet. The check valve 51 prevents a backflow of spray liquor to the broth pump 31 when the tube pressure accumulator 50 is full.

According to the invention, active ingredients are only added immediately before the broth pump 31, i.e. in the suction area, added to the carrier liquid in the supply line. The active ingredient is metered in by means of the at least one metering pump 10, which sucks the active ingredient from the reservoir 32. A flow connection between metering pump 10 and reservoir 32 can be shut off by means of a shut-off valve 59. The pre-container 32 is dimensionally stable and is connected to the large container 57 via a hose line. Before the start of spraying, active substance can be conveyed from the large container 57 into the preliminary container 32 by means of a rubber ball hand pump 60. If active substance is then removed from the preliminary container 32 by the metering pump 10, a negative pressure is created above the liquid level in the preliminary container 32, which ensures that active substance is continuously conveyed from the large container 57 into the preliminary container 32. The broth pump 31 and the metering pump 10 have a coupled drive, so that the same ratio of active substance and carrier liquid is always fed into the supply line. It is essential that the metering pumps 10 feed the active substance upstream of the broth pump 31 and thus on its suction side. Due to this arrangement of the metering pumps 10 in the overall system, the metering pumps 10 only have to apply a very low pressure for feeding the active substances, so that on the one hand simple pumps can be used and a further adjustment range with regard to the delivery capacity of the metering pumps can be realized. In addition, a selected ratio between active substance and carrier liquid can be precisely maintained by the feed on the suction side of the broth pump 31.

Pressure control in the system is carried out by regulating the drive speed of the broth pump 31. The flow meter 36 or pressure meter detects, for example, a pressure in the supply line and feeds the measured value to a control device (not shown). Depending on the pressure in the supply line, the control unit then tracks the drive speed of the broth pump 31.

In order to have spray liquor with the correct composition available directly at the spray nozzles 41 before the start of spraying, a pre-feed operation can be set. In the pre-conveying operation, the flushing valves 48, preferably electrically operated motor valves, are opened and thus connect the individual sections with the spray nozzles 41 to the return line 49, which in turn opens into the dilution tank 28. The return line 49 opens into the distributor pipe 42, which is arranged in the dilution tank 28 and extends over most of the height of the dilution tank 28. The distributor pipe 42 is evenly spaced and provided with through-openings, so that liquid coming into the dilution container 28 via the return line 49 is distributed substantially uniformly over the liquid wedge located in the dilution container 28. As already stated, the flushing valves 48 are opened and the metering pump 10 and the broth pump 31 are driven for pre-delivery. The carrier liquid from the storage container 27 is thereby mixed with active ingredient via the metering pump 10 and conveyed by means of the broth pump 31 to the individual spray nozzles 41 of the sections. Since the flushing valves 48 are open, the spray mixture flows back into the dilution tank 28 via the return line 49.

The pre-delivery takes place after actuation of a corresponding button for a predetermined time to be determined in the experiment. This time is determined in such a way that it can be assumed that an essentially uniform and correct active substance concentration is then present at the spray nozzles 41. After this predetermined time has elapsed, the purge valves 48 are closed and the broth pump 31 and the metering pump 10 continue to deliver until the rubber hose 52 in the tube pressure accumulator 50 has expanded against a gas pre-pressure in the housing 54 of the tube pressure accumulator 50. After reaching a predetermined pressure level, for example 6 bar, the broth pump 31 is stopped. After opening the spray nozzles 41 provided with pneumatic individual nozzle shutdown, the correct concentration of active substance and the correct spray pressure can then be sprayed immediately. The tube pressure accumulator 50 avoids delays and pressure fluctuations which are inevitable due to the start-up of the broth pump 31.

Contaminated carrier liquid flowing back into the dilution tank 28 via the return line 49 in the pre-delivery operation initially remains in the dilution tank 28, since a backflow into the storage tank 27 is prevented by the check valve 40. The contaminated carrier liquid in the dilution container 28 is then admixed during the spraying of the carrier liquid which is drawn in by the broth pump 31. The dilution container 28 is chosen to be so large that the active ingredient concentration obtained by the advance into the dilution container 28 is diluted to ineffectiveness. The liquid in the dilution container 28 can thus be easily fed to the broth pump 31 without noticeably influencing the active substance concentration in the carrier liquid.

As shown in the illustration in FIG. 6, by providing a jet pipe 44, which connects the dilution container 28 to the storage container 27, it can be ensured that the contaminated carrier liquid from the dilution container 28 only in a very low ratio to the carrier liquid from the Reservoir 27 of the broth pump 31 is supplied. The amount of water flowing in from the reservoir 27 is namely led through the jet pipe 44 to directly in front of the suction port 43 of the dilution container 28. which then leads to the broth pump 31. The carrier liquid flowing through the jet pipe 44 thus causes only a very slight turbulence when flowing through the dilution container 28, so that only small amounts of the contaminated content of the dilution container 28 are entrained. This results in a further considerable dilution of the content of the dilution container 28, so that even with a very low initial fill level of the storage container 27 and thus of the dilution container 28 or heavily contaminated liquid in the dilution container 28, it is ensured that active ingredients diluted to the ineffectiveness from the dilution container 28 get into the broth pump 31. Starting from the liquid level 45 in the dilution tank 28 shown in FIG. 5 and FIG. 6, the contaminated and already considerably prediluted content of the dilution tank 28 is mixed in by the drop in the liquid level 45 in the dilution tank 28, which drops in the same manner as the liquid level in the reservoir 27 drops. In this way, the content of the dilution container 28 is again distributed over the total amount of water carried through the jet pipe 44 from the storage container 27.

After the spray operation has ended, a rinsing operation can also be set in the crop protection spraying device according to the invention. For this purpose, the valve 59 between the reservoir 32 and the metering pump 10 is closed and a so-called flushing station 56 is connected to the inlet of the metering pump 10. The washing station 56, identified by the reference symbol A, is connected to a connection on the storage container 27, which is also identified by the reference symbol A. After connecting the flushing station 56 to the metering pump 10, the metering pump 10 is then put into operation together with the broth pump 31, so that the metering pump 10 can be flushed with water. In the flushing operation, the flushing valves 48 are also opened, so that contaminated carrier liquid flows through the Return line 49 is conveyed into the dilution tank 28. After the flushing operation has ended, the carrier liquid is contaminated with it, but considerably diluted, in the dilution container 28. This contaminated carrier liquid can then be applied during the next spraying run, as described above. Alternatively, the dilution container 28 can also be applied during a rinsing run, in which the metering pumps 10 are not connected to the preliminary containers 32.

Claims

claims

1 . Plant protection spraying device for direct dosing of active substances into a carrier liquid during spraying, with a storage container (27), a broth pump (31) for conveying the carrier liquid from the storage container (27) to at least one spray nozzle (41) along at least one supply line, at least one active substance container ( 32) and at least one dosing pump (10) for mixing active substances from the active substance container (32) into the at least one supply line, characterized in that the at least one dosing pump (10) for mixing the active substance upstream of the broth pump (31) is connected to the supply line is.

2. Plant protection sprayer according to claim 1, characterized in that the metering pump (10) and the broth pump

(31) can be driven coupled by means of a common drive.

3. Plants protection device according to claim 1 or 2, characterized in that the spray pressure is regulated by regulating the delivery rate of the broth pump (31).

4. Plant protection spraying device according to at least one of the preceding claims, characterized in that the broth pump (31) and the at least one metering pump (10) are arranged on a central rod part.

5. crop protection spraying device, in particular according to one of the preceding claims, for direct dosing of active ingredients in a carrier liquid during spraying, with a reservoir (27), a broth pump (31) for conveying the carrier flow liquid from the storage container (27) along a supply line to at least one spray nozzle (41), at least one active substance container (32) and at least one metering pump (10) for admixing active substances from the active substance container (32) into the at least one supply line, characterized in that that a dilution tank (28) and at least one return line (49) which can be shut off by means of a shut-off valve (48) are provided, the return line (49) branching off from the supply line in the region of the spray nozzles (41) and opening into the dilution tank (28).

6. Plant protection spraying device according to claim 5, characterized in that the dilution container (28) can be connected to the supply line.

7. Plant protection device according to claim 6, characterized in that the dilution container (28) is permanently in flow connection with the storage container (27).

8. Pflan∑enschuf∑sprifzvorrichtung according to claim 6 or 7, characterized in that between the dilution tank (28) and reservoir (27) a check valve (40) is provided, which prevents flow from the dilution container (28) to the reservoir (27).

9. crop protection spraying device according to at least one of claims 6 to 8, characterized in that means are provided to mix the content of the dilution container (28) during the spraying in a ratio in the supply line, so that the content of the dilution container (28) up to Ineffectiveness diluted gets into the supply line.

10. A crop protection spraying device according to at least one of claims 6 to 9, characterized in that a jet pipe (44) connected to the storage container opens into the dilution tank (28), the jet pipe (44) being connected to the broth pump (31) directly before one Suction port (43) of the dilution tank (28) is guided.

11. Plant protection spraying device according to at least one of the preceding claims, characterized in that a pressure accumulator is provided in the supply line between the broth pump (31) and the spray nozzles (41).

12. Plant protection spraying device according to claim 1 1, characterized in that the pressure accumulator is designed as a tubular pressure accumulator (50) with an elastic hose component (52) in a housing (54), the hose component (52) being able to expand within the housing (54) ,