EP1902774A1 - Mixing device, spraying device for pest management and method for operating a spraying device - Google Patents

Abstract

The device (10) for mixing carrier liquid with active substance for field syringe for plant protection, comprises mainstream line (12a, 12b), active substance supply line (18), a mixing chamber (16), and a downstream line (14a, 14b) connected with an injector-agitating nozzle arranged in the mixing chamber. The mixing chamber is branched in one of the main stream line and arranged in the downstream line. Units are intended to guide a mainstream to complete stream or a part of the stream through the mainstream line and the downstream line in dependence of a size. The device (10) for mixing carrier liquid with active substance for field syringe for plant protection, comprises mainstream line (12a, 12b), active substance supply line (18), a mixing chamber (16), and a downstream line (14a, 14b) connected with an injector-agitating nozzle arranged in the mixing chamber. The mixing chamber is branched in one of the main stream line and arranged in the downstream line. Units are intended to guide a mainstream to complete stream or a part of the stream through the mainstream line and the downstream line in dependence of a size. Units are intended to define a size of the downstream flow branched from the main stream line and/or to limit a maximum value. Independent claims are included for: (1) an injection device for atomizing of injecting unit for the plant protection; and (2) a method for the operation of an injection device for the plant protection.

Description

The invention relates to a mixing device for mixing a carrier liquid with at least one active ingredient, in particular for a field sprayer for crop protection, with a main flow line, an active ingredient feed line and a mixing chamber. The invention also relates to a spraying device for spraying tips for crop protection. Furthermore, the invention relates to a method for operating a spray device for crop protection.

Sprays in agriculture or plant protection technology are made from active ingredients and carrier liquid, wherein the ratio of active ingredient to carrier liquid can vary extremely. For example, drug levels of about 200 ml to about 6 liters per hectare to be sprayed are used. Should the active ingredients and the Carrier liquid not mixed as usual today before the treatment, ie the spraying, in a container, but are dosed directly during the treatment, the supply of these agents must be carried out in a flow of the carrier liquid, which in turn also has a very broad spectrum. This is in spatial cultures, for example, at 150 to 450 I per hectare to be treated. Since the momentarily flowing volume flow of the carrier liquid during spraying is, in addition to the application rate per hectare, also from the driving speed and the number of used sections or spray nozzles of the crop protection syringe, a spectrum of the volume flow of the carrier liquid, for example in a range of 8 l / min to 250 l / min. In the case of injection devices with direct dosing, in which the active substance is thus mixed with the carrier liquid during the injection device itself, the good mixing of the active ingredient and the carrier liquid is a difficult requirement if the entire area to be covered is considered. Not only the ratio of active ingredient to carrier liquid vary greatly between different applications, in the same application beyond the volume flow of spent carrier liquid can vary widely.

Known mixing chambers for mixing two or more liquid components have the disadvantage that they work reliably only in a limited range of volume flows of the carrier liquid flow and only from a certain amount of supplied active ingredient. In the pulse-shaped metered addition of active ingredient, the known mixing chambers therefore only work reliably above a certain frequency of the metering pulses. The size of the mixing chambers must in turn be designed for the volume flow to be mixed, so that high volume flows also require correspondingly large mixing chambers or complex stirring systems. For mobile use, eg on one Plant protection syringe, the known mixing chambers are therefore very limited.

The invention provides a compact mixing device for mixing a carrier liquid with at least one active substance, with which a wide range of active ingredient / carrier liquid ratio and a wide range of volume flow can be covered with reliable mixing.

According to the invention for this purpose, a mixing device for mixing carrier liquid with at least one active ingredient, in particular for a sprayer for crop protection, an active ingredient feed line and a mixing chamber is provided, wherein the mixing chamber is arranged in a branching off from the main flow line and re-opening into this bypass line.

By the invention, the mixing chamber is not arranged in the main flow line, but in a bypass line, the at least one active ingredient and the carrier liquid can be mixed in a mixing chamber, which is tuned to the side stream, which does not fluctuate or substantially less than the main flow in the main power line. The mixing chamber can be optimally tuned to the secondary flow and run relatively small. If the added active ingredients, for example pesticides, are mixed sufficiently reliably with the secondary stream of the carrier liquid, for example water, the secondary stream is added again as a continuously flowing component to the main stream and mixed in in a customary manner, for example by means of a known mixer. The mixing device according to the invention can ensure a reliable mixture of active substance and carrier liquid especially when the active substance or the active ingredients are added in pulses. In known mixing devices is in a direct feed of in Pulses dosed agents in the very wide flow rate does not ensure a sufficient mix, since at low flow rates sufficient flow is not present to achieve a mixture, and at high flow rates, the time in which a mixing chamber is traversed too short to one sufficient distribution of the pulse-fed amounts of active ingredient in the longitudinal direction of the volume flow to achieve.

In a further development of the invention, the drug feed line opens into the bypass line or into the mixing chamber.

In this way, the full metered amount of active ingredient in the bypass line and the mixing chamber, so that a reliable and uniform mixing can be ensured.

In a further development of the invention, a throttle is arranged in the main flow line downstream of the branch of the bypass line and upstream of the junction of the bypass line.

As a throttle, for example, a throttle valve or a check valve may be provided. The throttle determines the pressure applied across the mixing chamber. With this pressure or this pressure difference, the mixing chamber located in the bypass flow is then flown and operated, for example, a hydraulic agitator.

In one embodiment of the throttle as a check valve, for example, the complete main flow is diverted into the bypass line, as long as the opening pressure of the check valve is not exceeded in the main flow line. If the opening pressure of the check valve is exceeded when the main flow continues to increase, a pressure difference corresponding to the opening pressure of the check valve is still maintained via the bypass flow line and as a result, part of the main flow flows into the bypass duct, the other part continues to flow through the check valve in the main flow duct. Ideally, the volume flow in the bypass line, for which the mixing chamber is designed to correspond to the smallest possible main flow, so that even under these conditions, a perfect mixture is ensured in the mixing chamber. However, the check valve in the main flow also has an increasing pressure difference over the bypass line with increasing volume flow, so that the size of the secondary flow always depends on the size of the main flow. However, the resulting increase in the volume flow in the bypass line can be accepted, as this, for example, a stirrer in the mixing chamber is more strongly flowed and thus a proportionally higher stirring power almost compensates for the faster flow through the mixing chamber.

In a further development of the invention, a further mixer is provided in the main flow line downstream of the junction of the bypass line.

By means of such a downstream further mixer can then be achieved at higher flow rates an intimate mixture between inflowing side stream and the main stream. Since the active ingredient is already thoroughly mixed in the secondary flow, the requirements for mixing secondary flow and main flow are much lower and commercially available mixers are sufficient to achieve satisfactory results.

In a development of the invention, means are provided in order to guide the complete main flow or only part of the main flow through the bypass flow, depending on a size of a main flow flowing through the main flow line.

For a small main flow, the complete main flow is expediently passed through the bypass flow line, and only when the main flow exceeds a predefined size, a part of the main flow is diverted parallel to the secondary flow through the main flow line. Such control of the main flow and the secondary flow can be effected automatically by the throttling action described, for example by means of the check valve described, or also by means of a controlled or regulated valve.

In a development of the invention, means are provided to define a size of the secondary flow shown from the main flow line and / or to limit it to a maximum value.

In this way, an optimal mixture can always be ensured, since the mixing chamber can be tuned to a narrow range between a minimum carrier liquid flow, which is then passed completely into the bypass duct, and the maximum bypass flow. Small excesses of the maximum value of the diverted secondary flow can be tolerated. It is essential that in the case of large volume flows a two-stage mixture takes place, namely by first mixing the amounts of active substance metered in pulses with a branched off secondary stream and only then mixing the already mixed and continuous secondary stream with the remaining main stream. By means of such a cascaded mixture, it is possible to reliably cover the extremely wide ranges of the ratio of active substance to carrier liquid and the total volume flow required in plant protection technology, especially in the case of pulse-capable metered addition of the active substance.

In a preferred embodiment of the invention, for defining the branched off from the main flow line side stream and for limiting this side stream to a maximum value, for example a Injektorrührdüse be used, which is also used as a hydraulic agitator. The nozzle cross-section of the injector stirring nozzle determines, depending on the pressure difference between the diversion of the secondary flow from the main flow line and the introduction of the secondary flow into the mixing chamber whose size, ie the flow rate of the secondary flow.

In a further development of the invention, the bypass line is connected to a arranged in the mixing chamber injector-stirring nozzle.

With such an injector-stirring nozzle, a good mixing without mechanically moving parts can be achieved. It is particularly advantageous that a higher stirring power is automatically achieved with a magnitude larger sidestream.

In a further development of the invention, a bypass line branching off from the bypass line upstream of the mixing chamber and opening into the mixing chamber is provided. Appropriately, a switchable bypass valve is provided in the bypass line.

By means of such a bypass line, which bypasses, for example, an injector-stirring nozzle at the entrance of the mixing chamber, the mixing chamber can be flushed, for example in a rinsing operation with very large amounts of liquid. By way of example, very large amounts of by-pass streams can also be introduced into the mixing chamber during spraying operation via the bypass line, for example, if only smaller demands are placed on the uniformity of thorough mixing. In a purging operation, the bypass valve would be opened, in normal mixing operation, however, the switchable bypass valve is closed.

The problem underlying the invention is also solved by a spray device for spraying spraying agents for crop protection, in which at least one metering pump and a mixing device according to the invention are provided.

With such a spray device, an extremely wide range of active ingredient per hectare and in terms of a carrier liquid flow with reliable mixing and direct dosing can be covered.

In a further development of the invention, the metering pump metered the at least one active ingredient in a pulse shape in the bypass line upstream of the mixing chamber or in the mixing chamber.

The metering of active ingredients in liquid pulses each having the same amount of liquid has the advantage that a very precise metering is possible, wherein different amounts of active ingredient are accomplished by simply increasing or decreasing the pulse frequency.

The problem underlying the invention is also solved by a method for operating a spraying device for plant protection, in which the following steps are provided:

Conveying a carrier liquid in a main flow line, depending on a size of a carrier liquid stream in the main flow line and / or an amount of active ingredient to be metered into the carrier liquid stream, branching off a secondary stream from the carrier liquid stream, continuously mixing the amount of active ingredient to be metered with the side stream and optionally mixing the side stream with the remaining carrier liquid stream in the main power line.

Despite the use of a compact mixing chamber which is suitable for mobile use on a field sprayer, the method according to the invention makes it possible to reliably mix and homogenize directly metered active substances into a very widely varying carrier liquid flow.

In a further development of the invention, it is provided to define the secondary flow and / or to limit it to a maximum value. Appropriately, the dosing of the active ingredient in the secondary stream is pulsed.

By adjusting the secondary flow and limiting the secondary flow to a maximum value, which can be achieved for example by a nozzle or throttle in the secondary flow, it is ensured that in the secondary flow mixing chamber only flows are mixed, which are within a normal working range of the mixing chamber. Optionally, another mixer is required downstream of the junction of the secondary flow into the remaining main flow. As already stated, however, the mixing of the already mixed, continuous secondary flow with the remaining main flow is comparatively uncritical and can be achieved reliably with known mixers.

Fig. 1

eine schematische Darstellung einer erfindungsgemäßen Mischvorrichtung und

Fig. 2

eine schematische Darstellung einer erfindungsgemäßen Spritzvorrichtung mit der Mischvorrichtung der Fig. 1.

Further features and advantages of the invention will become apparent from the claims and the following description of a preferred embodiment of the invention taken in conjunction with the drawings. In the drawings show:

Fig. 1

a schematic representation of a mixing device according to the invention and

Fig. 2

a schematic representation of a spray device according to the invention with the mixing device of Fig. 1st

The schematic representation of FIG. 1 shows a mixing device 10 according to the invention in an exemplary preferred embodiment, with a main flow line 12, a branching off from the main flow line 12 and back into this branching bypass line 14, wherein the bypass line 14 leads to a mixing chamber 16 and from this from back to the main power line 12 goes. A drug delivery line 18 opens shortly before the confluence of the bypass line 14 in the mixing chamber 16, in the bypass line 14. The active ingredient is metered in pulses via the active ingredient line 18 in the bypass line 14, which is symbolized by the dashed representation of the drug supply line 18. In the active compound line 18, however, there is not alternating air and active substance, the dashed representation is intended to indicate only that from the active ingredient supply line 18 in the bypass line 14 no continuous flow of active ingredient is introduced, but this drug stream flows in a pulsed manner.

The bypass duct 14 opens into an injector stirring nozzle 20 which is arranged within the mixing chamber 16 and, as indicated by arrows within the mixing chamber 16, ensures a thorough turbulence and thorough mixing of the liquid in the mixing chamber 16. At the top in Fig. 1 bottom surface of the mixing chamber 16, in the center of the injector-stirring nozzle 20 is disposed radially outwardly an outlet 22, from which the downstream of the mixing chamber 16 lying portion 14b of the bypass line 14 goes out and back into the Main power line 12 opens. The outlet 22 is always arranged in the opposite flow direction to the injector-stirring nozzle 20, so that from the injector-stirring nozzle 20 to the outlet 22 so a flow reversal must take place. Between the branch of the bypass line 14 from the main flow line 12 and the junction of the Secondary flow line 14 in the main flow line 12, a check valve 24 is arranged. Downstream of the junction of the bypass duct 14 in the main flow line 12, a mixer 26 is optionally provided, which ensures thorough mixing of the secondary flow from the bypass duct 14 with the main flow in the main flow line 12.

The main flow line 12 is divided into a portion 12 a upstream of the check valve 24 and a portion 12 b downstream of the check valve 24. The bypass duct 14 has two sections 14a, 14b, with the section 14a upstream of the mixing chamber 16 and the section 14b downstream of the mixing chamber. The portion 14a of the bypass duct thus branches off from the portion 12a of the main flow line 12 and opens into the mixing chamber 16. The portion 14b of the bypass duct 14 emanates from the mixing chamber 16 and opens into the portion 12b of the main flow line 12 downstream of the check valve 24th

The check valve 24 has a predefined opening pressure. When a volumetric flow flows in the main flow line 12, the check valve 24 in the main flow line 12 generates a pressure drop or a pressure difference between the sections 12a upstream of the check valve 24 and the section 12b downstream of the check valve. This pressure difference generated by the check valve 24 causes the flow through the arranged in the bypass mixing chamber 16 and operates in the illustrated embodiment, the hydraulic agitator in the form of the injector-stirring nozzle 20. As long as this opening pressure is not exceeded by the main flow in section 12a of the main power line 12, the complete main flow is diverted from the main flow line 12 into the section 14a of the bypass line 14. Only then, when the opening pressure of the check valve 24 in section 12a of the main power line exceeded a portion of the main flow is diverted into the portion 14a of the bypass line and a portion passes through the check valve 24. Even after the check valve 24 has opened, the pressure drop across the check valve 24 substantially corresponds to its opening pressure, so that the mixing chamber 16 always with an approximately constant pressure is applied. As a result, the size of the secondary flow, which is passed through the mixing chamber 16, within narrow limits, wherein the size of the secondary flow results from the pressure with which the injector-stirring nozzle 20 is flown, and the nozzle cross-section.

If the main flow continues to increase in the section 12a of the main flow line, then a larger secondary flow will flow through the mixing chamber 16 in accordance with the then greater pressure loss at the check valve 24, but the conditions within the mixing chamber 16 will not change so much that a lack of mixing to be feared. This can be achieved on the one hand by a corresponding design of the check valve 24, which is advantageously designed so that the pressure loss does not rise disproportionately with increasing volume flow, and on the other hand in that the injector-stirring nozzle 20 in the mixing chamber 16 at a larger flow and a greater stirring power provides. Despite a then larger side stream in the mixing chamber 16, a satisfactory mixture between the active ingredients from the active ingredient supply line 18 and the carrier liquid from the section 14a of the bypass line can still be ensured.

The mixing device 10 further has a bypass valve 28, which can shut off or release a bypass line 30. The bypass line 30 branches off upstream of the junction of the active ingredient feed line 18 from the portion 14 a of the bypass line and opens at an inlet 32 directly into the mixing chamber 16 Injection process to accelerate the concentration reduction and the flushing of the entire mixing device 10, the bypass valve 28 is opened and carrier liquid flows not only through the injector-stirring nozzle 20, but also via the inlet 32 into the mixing chamber 16 a. Within a short time, the mixing chamber 16 can thereby be reliably cleaned of active substance residues. In normal mixing operation, the bypass valve 28 is closed and is thus in the position shown in Fig. 1. The bypass valve 28 can be controlled pneumatically, for example.

The schematic representation of FIG. 2 shows a spray device 40 according to the invention with the mixing device 10 of FIG. 1. The section 12a of the main flow line 12 is fed with carrier liquid from a carrier liquid tank 42, wherein a carrier liquid pump, not shown, is provided. Downstream of the mixer 26, the main flow line section 12b leads to a spray bar 44 having a plurality of spray nozzles.

The drug delivery line 18 is fed by a metering pump 46, the active ingredient is supplied from a drug reservoir 48. The metering pump 46 outputs pulses of liquid each having the same amount of liquid and operates under the control of a control unit 50. The control unit 50 receives, inter alia, information about the flowing in the main flow line 12a carrier fluid quantity and ensures by appropriate adjustment of the pulse frequency for the metering pump 46 sure that a preset drug / Carrier liquid ratio is maintained.

By arranging the mixing device 10 according to the invention in a bypass branch of the spray device 40, it can be ensured that a satisfactory mixing of active ingredient and carrier liquid over an extremely wide range of active ingredient per hectare surface to be sprayed is ensured even with pulsed metering of at least one active substance and carrier liquid flow.

Claims (10)

Mixing device for mixing a carrier liquid with at least one active ingredient, in particular for a field sprayer for crop protection, with a main flow line (12a, 12b), an active ingredient feed line (18) and a mixing chamber (16), characterized in that the mixing chamber (16) in one from the main flow line (12a, 12b) branching and again in this branching off-flow line (14a, 14b) is arranged. Mixing device according to claim 1, characterized in that means are provided to guide the complete main flow or only part of the main flow through the bypass duct (14a, 14b) in dependence on a size of a main flow flowing through the main flow duct (12a). Mixing device according to at least one of the preceding claims, characterized in that means are provided for defining a size of the branched off from the main flow line (12a) secondary flow and / or to limit to a maximum value. Mixing device according to at least one of the preceding claims, characterized in that the bypass duct (14a) is connected to an in the mixing chamber (16) arranged injector-stirring nozzle (20). Spray device for spraying pesticides for plant protection, characterized by a metering pump (46) and a mixing device (10) according to at least one of the preceding claims. Spray device according to claim 5, characterized in that the metering pump (46) metered at least one active ingredient in a pulse shape into the bypass duct (14a) upstream of the mixing chamber (16) or into the mixing chamber (16). Spray device according to claim 6, wherein in the mixing device, the active ingredient supply line (18) opens into the bypass line (14a) or into the mixing chamber (16) and wherein a control device (50) is provided for controlling the metering pump (46) and the metering pump in dependence in the main flow line (12a) stömenden carrier liquid quantity is controlled. Method for operating a spraying device for plant protection, characterized by the following steps: Conveying a carrier liquid in a main flow line (12a, 12b), as a function of a size of a carrier liquid flow in the main flow line (12a, 12b) and / or an amount of active substance to be metered into the carrier liquid flow, branching off of a secondary flow from the carrier liquid flow, - Continuous mixing of the dose of active ingredient with the side stream and optionally mixing the secondary stream with the remaining carrier liquid stream. Method according to claim 8, characterized by defining and / or limiting the secondary flow to a maximum value. A method according to claim 8 or 9, characterized by pulsed metering of the active ingredient in the side stream.

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