EP2609329B1 - Spray gun for expelling a fluid - Google Patents

Description

The present invention relates to a spray gun for ejecting a fluid. The spray gun comprises at least one cylinder in which a piston is movably mounted. In the cylinder, a fluid chamber is formed whose volume is variable by a movement of the piston and in which at least one first cylinder opening is formed. The spray gun further includes an injection port communicating with the first cylinder port of the cylinder via a communication line so that fluid received from the fluid chamber, which is forced out of the fluid chamber by the pressure exerted by the piston through the first cylinder port, via the communication line reaches the injection opening and is ejected there. The spray gun is designed in particular for ejecting pesticides.

It is known to expel liquids by means of a so-called spray bottle. In this case, a pumping mechanism acts directly on the liquid that is expelled through a nozzle. Furthermore, it is known in spray devices to increase the air pressure by means of a pump mechanism in a chamber which receives the ejected water. Then, when a trigger is actuated, the water in the chamber is splashed outwardly through a nozzle due to the pressurized air in the chamber.

From the EP 0 462 749 B1 is a spray gun is known, which is operated by means of a hand lever. The spray gun has a connection for a liquid supply via which pressurized liquids are supplied to the spray gun. At the outlet end of the spray gun, an outlet nozzle is provided to eject liquid in a particular spray pattern. Between the connection for the liquid supply and the outlet nozzle, a control valve is provided, which can be opened by means of a trigger.

The EP 1 136 135 B1 describes a fluid pump dispenser with a piston mechanism. In this pump dispenser, the formation of droplets or drops of the product at the outlet opening is avoided by feeding the product into the pump chamber at the beginning of each piston return stroke.

In the DE 196 12 524 A1 a spray gun is described, which is designed in particular for ejecting medium to thick viscous liquids, such as pasty adhesives. The spray gun has a Stoffzufuhr- and a fabric outlet nozzle. In between a piston chamber is arranged, in which a piston back and forth can be moved. The piston is coupled to a shift lever. By operating the shift lever, the flow through the piston chamber can be closed and opened by movement of the piston. In the shift lever designed as an inductive proximity switch sensor switch is provided, which shuts off the mass transport at the approach of the shift lever at a predetermined proximity state. At the same time, the motive pressure of the mass transport is reduced before the fabric transport closure takes place. In this way, a subsequent flow of material is to be prevented.

Furthermore, spray guns are known in which by means of a pressure difference, a liquid is atomized to small droplets. For example, the substance to be ejected can be sucked out of a container by means of a Venturi tube and then atomized. Such spray guns are used for example for spraying paint. In this case, it is also known to pressurize the paint by means of a pump and to press through a nozzle so that the paint is finely atomized.

From the US 5,441,180 Finally, a spray gun is known, which is designed in particular for the ejection of pesticides. This spray gun comprises a reservoir for the pesticide to be ejected. Furthermore, the spray gun comprises a pivotable trigger, through which a piston is movable. By the movement of the piston, the volume in a chamber in which the pesticide to be ejected is reduced, so that the pesticide is ejected. When the trigger is swung back again, the piston is moved in the opposite direction, increasing the volume of the chamber. As a result, a negative pressure is generated, which sucks the pesticide back from the discharge opening.

Plant protection products are usually used in the form of liquid active ingredient preparations. These are usually obtained by diluting commercially available active substance concentrates, such as suspension concentrates (SC), oil dispersions (OD), capsule dispersions (CS), emulsifiable concentrates (EC), dispersible concentrates (TLC), emulsions (EW, EO), suspoemulsion concentrates (SE), solution concentrates (SL), water-dispersible and water-soluble powders (WP and SP), water-soluble and water-dispersible granules (WG, SG) with or in water. In addition, products in the form of active ingredient solutions are also used which contain the active substance in a concentration suitable for the application, so-called ULVs. Furthermore, to combat arthropoder pests often containing active ingredient gels, which may be diluted with water to the desired use concentration before use. Here and below, therefore, the term "crop protection agent" is used both for liquid drug formulations, including drug-containing gel formulations, with a drug concentration suitable for the application as well as for liquid drug formulations, including dilute gel formulations obtainable by diluting drug concentrates.

When spraying or spraying pesticides with a spray gun, it is particularly important that the spray gun can be handled safely and easily. The spray gun should be suitable for mobile use, i. she should be easily carried by a person. Furthermore, it is of particular importance that the ejected fluid, i. the plant protection product, can be dosed very accurately. Finally, the pesticide should be applied by means of the spray gun from a certain distance exactly on a desired surface. It should be ensured that in the discharge process no pesticide can get into areas that should not come into contact with the pesticide. In particular, it should be ensured that it can not happen that the user comes into contact with the plant protection product. In addition, dripping at the end of the ejection process should be avoided. The spray gun should in particular also be suitable for application of gels containing active ingredient, for example active ingredient-containing gels for controlling arthropod pests, and permit targeted application, for example in the form of spots or bands / strands. The sharpening gun should also be insensitive to inhomogeneities of the liquid pesticide, as they may occur, for example, when preparing the active ingredient preparation used for diluting the commercially available active ingredient concentrates with or in water to the desired concentration for the application.

The present invention has for its object to provide a spray gun of the type mentioned, in which by the ejection process, a coherent spray jet is generated, which completely reaches its target area. Further, leakage of the fluid after completion of the ejection operation, i. a dripping of fluid can be prevented.

According to the invention this object is achieved by a spray gun with the features of claim 1. Advantageous embodiments and further developments emerge from the dependent claims.

The spray gun according to the invention is characterized in that a fluid valve is arranged in the connecting line. Furthermore, a sensor is provided in the cylinder, with which a defined position of the piston, in which there is still fluid in the fluid chamber during the ejection process, can be detected. In addition, with the sensor, the fluid valve can be actuated, wherein the fluid valve is closed by means of the sensor when the defined position of the piston has been detected.

In the context of the invention, a spray gun is understood to mean a device with which a fluid can be ejected, sprayed, sprayed or atomized through an opening. By the spray gun according to the invention, however, in particular a fluid jet can be generated at the outlet.

The spray gun according to the invention has a piston metering or piston pumping device. A fluid in the fluid chamber is pushed out of it by the movement of the piston in the cylinder. Such piston metering devices often have the problem that at the end of the discharge operation, when there is little more fluid in the fluid chamber, the pressure through which the fluid is expelled falls. This pressure drop causes the ejected fluid jet to break off. The last ejected fluid quantity no longer has the same ejection velocity as previously expelled fluid volumes, so that the exhausted fluid no longer arrives at the target like the previous fluid volumes. As a result, part of the ejected fluid jet reaches an area between the target surface and the spray gun. This is particularly disadvantageous when pesticides are expelled with the spray gun.

In the spray gun according to the invention, this decrease in the speed at the end of the fluid ejection can be prevented. The sensor ensures that the fluid valve is closed when the maximum pressure from the piston is still exerted on the residual fluid in the fluid chamber. The last ejected fluid amount therefore still has the same ejection speed as the previously ejected fluid volumes. In this way, a contiguous fluid jet may be generated in which all the ejected fluid has substantially the same velocity so that the total amount of fluid expelled during the ejection process reaches the desired target area. In particular, there is no drop in the discharge speed at the end of the discharge operation, so that it is ensured that no areas between the target of the discharge operation and the spray opening of the spray gun come into contact with the ejected fluid. This is special then advantageous if it is the ejected fluid to a pesticide, in particular a liquid, especially gelatinous, highly viscous crop protection agent is.

The defined position of the piston, in which the sensor closes the fluid valve, is chosen in particular so that there is still so much fluid in the fluid chamber that it has not come to a pressure drop at the injection port at the end of the ejection process. The piston has not reached its final position in the cylinder, in particular at this position, in which it abuts a cylinder wall.

In one embodiment of the spray gun according to the invention, the defined position of the piston is detected by the sensor by a magnetic field generated or changed by the piston. In the piston, for example, a permanent magnet may be integrated, which generates a magnetic field whose field strength depends on the location of the sensor on the position of the piston. If the field strength of the magnetic field at the sensor exceeds or falls below a certain limit value, the state of the sensor changes. This state change is utilized in the spray gun according to the invention, in order to bring about a closing of the fluid valve. The limit for the field strength of the magnetic field is set so that the piston is in this case at the desired position within the cylinder at which no pressure drop occurs during the ejection process.

In particular, the sensor comprises a so-called reed contact. In a reed contact, an electrical contact is closed when the field strength of the magnetic field at the location of the sensor exceeds a limit.

The sensor of the spray gun according to the invention thus detects during the ejection process, the position of the piston by a measured value, which depends directly on the position of the piston in the cylinder. Thereby, the position of the piston in the cylinder can be detected with high accuracy. The subsequent electronic processing of the signal generated by the sensor, the ejection process can be terminated very accurately, whereby a pressure drop at the end of the ejection process is avoided.

During the ejection process, in the case of the spray gun according to the invention, the piston exerts a pressure on the fluid in the fluid chamber. In order to exert this pressure on the fluid by means of the piston, a force must act on the piston. For this purpose, for example, be formed in the cylinder, a pressure chamber in which at least one second cylinder opening is formed, which is connected to a first connection for a compressed gas line, in particular a compressed air line. Pressure gas can thus enter the pressure chamber via the second cylinder opening. When the pressure in the pressure chamber exceeds the pressure in the fluid chamber, the movable piston is urged toward the fluid chamber in which the fluid is located. Thus, the volume of the pressure chamber is increased and the volume of the fluid chamber is reduced, whereby the fluid is forced out through the first cylinder opening. At the same time, the pressure can be kept constant by the connection of the first port to the compressed gas line in the pressure chamber, so that a constant pressure is exerted on the fluid in the fluid chamber by the piston during the ejection process.

According to a further embodiment of the spray gun according to the invention, this additionally or alternatively has a compression spring which acts between a stop and the piston. The compression spring can exert a force on the piston in the direction of a reduction of the volume of the fluid chamber. In this case, it is possible to form the spray gun so that no pressure chamber is formed and the cylinder is not connected to a compressed gas line. The piston pressure is generated in this case solely by the compression spring. The pressure exerted on the fluid during filling of the fluid chamber may then have to exceed the pressure exerted by the compression spring, so that when filling the fluid chamber with the fluid, the compression spring is compressed and increases the volume of the fluid chamber. Furthermore, however, it is possible to provide the compression spring in addition to the pressure chamber. In this case, the compression spring supports the pressure exerted by the pressurized gas in the pressure chamber on the piston.

The spray gun according to the invention may further comprise an adjusting device, with which the movement of the piston in the cylinder and thus the maximum volume of the fluid chamber can be limited. By means of the adjusting device can thus be set exactly the ejected during the ejection process fluid volume.

According to another embodiment, the sensor is adjustable in the longitudinal direction of the cylinder. In this case, by adjusting the position of the sensor relative to the cylinder, the ejected fluid volume can be adjusted.

According to a development of the spray gun according to the invention, this has a second connection for a fluid reservoir. The fluid reservoir may be integrated in the spray gun. However, when the fluid reservoir absorbs larger amounts of fluid is intended, the fluid reservoir is provided separately from the spray gun, so that the spray gun, the fluid is supplied via the second port. This second connection can be connected to a further cylinder opening, via which fluid can be supplied to the fluid chamber. However, it is also possible for the second connection to be connected to the first cylinder opening, so that the fluid can be conveyed into the fluid chamber via the second connection and the first cylinder opening. Through the first cylinder opening, the fluid thus enters both into the fluid chamber of the cylinder and out of this fluid chamber.

In this case, it is also possible to design the fluid valve as a first 3/2-way valve, wherein in a first position, a fluid passage from the first cylinder opening is provided to the injection port and in a second position, a fluid passage from the second port to the first Cylinder opening is provided.

A 3/2-way valve is understood to mean a valve with three connections and two switching positions. The fluid reservoir or the second connection, the spray opening and the first cylinder opening are connected to the three connections of the valve. In the first position of the valve, a passage is provided from the first cylinder port to the injection port, the passage being closed from the fluid reservoir and the second port, respectively, to the first cylinder port. In the second position of the valve, a fluid passage is provided from the fluid reservoir or the second port to the first cylinder port, wherein the passage from the first cylinder port to the injection port is closed. By the first 3/2-way valve thus takes place both the fluid transport to the injection port during the ejection process and the fluid transport for filling the fluid chamber of the cylinder for the fluid.

Furthermore, in the case of the spray gun according to the invention, a compressed gas valve designed as a second 3/2-way valve can be arranged between the first connection, via which a compressed gas can be supplied to the spray gun, and the second cylinder opening. In the first position of this compressed gas valve, a compressed gas passage is provided from the first port to the second cylinder port. In the second position of the compressed gas valve, a pressure reduction of the compressed gas within the pressure chamber is made possible. For example, in the second position, a compressed gas passage can be provided from the second cylinder opening to the outside.

According to a development of the spray gun according to the invention, the fluid reservoir is connected on the one hand to a device for providing pressurized gas, in particular compressed air. The device may be, for example, a compressed air tank, a compressor and a hand pump. The fluid can also be placed directly under pressure, z. B. by a pump. On the other hand, the fluid reservoir is connected via a line to the first port of the compressed gas valve. It is thus provided a connection from the compressed gas valve to the fluid reservoir. This compound can be integrated into the spray gun or be formed separately from the spray gun. In the second position of the compressed gas valve can thus be applied to the pressure chamber with compressed gas. Furthermore, pressurized gas is applied to the fluid reservoir to provide fluid transport for filling the fluid chamber of the cylinder.

According to one embodiment of the spray gun according to the invention, the sensor is coupled to the first and second 3/2-way valve. In this case, the sensor switches the first and the second 3/2-way valve in the second position when the piston is at the defined position, so that the fluid discharge is interrupted by the injection port and fluid by means of the compressed gas from the fluid reservoir on the first 3 / 2-way valve is conveyed into the fluid chamber. After the sensor has finished the ejection process, the fluid chamber of the cylinder is automatically filled again with fluid via the two 3/2-way valves. The circuit of the valves takes place in particular electronically. Preferably, the two valves are switched simultaneously when the piston is at the defined position, or it is first the first 3/2-way valve for the fluid and shortly thereafter the second 3/2-way valve for the compressed gas switched.

The spray gun also has a trigger. This trigger initiates the ejection process. According to one embodiment of the spray gun according to the invention, the trigger is coupled to the first and second 3/2-way valves. Upon actuation of the trigger this switches the first and the second 3/2-way valve in the first position, so that by the compressed gas in the pressure chamber, the piston is moved so that the volume of the fluid chamber is reduced and thereby expelled fluid through the injection port becomes. After the trigger has been actuated, the second 3/2-way valve for the compressed gas and shortly thereafter the first 3/2-way valve for the fluid is preferably switched in this case first. In this way it can be ensured that the maximum pressure on the fluid in the fluid chamber is exerted already at the beginning of the ejection process.

In particular, the trigger is an electronic trigger, upon actuation of which a control signal is transmitted. Furthermore, the fluid valve and / or the compressed gas valve can be actuated electromagnetically. In this case, the spray gun may comprise an electronic control device which is data-technologically coupled to the sensor, the fluid valve and / or the compressed gas valve. Depending on a signal generated by the sensor then the fluid valve and / or the compressed gas valve can be actuated. These operations are controlled by the electronic control device. The control device may in particular comprise a relay or a microprocessor for this purpose.

The electronic control of the valves and the electronic trigger for the spray gun, it is possible to construct the mechanical structure of the spray gun very simple. This makes it possible to achieve a reduction of the weight of the spray gun, which is particularly advantageous in a mobile use of the spray gun. The electronic control of the valves ensures that the fluid output can be controlled very precisely, which is important in particular when expelling pesticides.

In an alternative embodiment of the spray gun according to the invention, a first and a second fluid chamber are formed in the cylinder. In the first fluid chamber, at least one first cylinder opening is formed. In the second fluid chamber, at least one second cylinder opening is formed. In this alternative embodiment, the fluid received by the first fluid chamber can be forced out by forcing fluid into the second fluid chamber under pressure, thereby exerting a force on the piston in the direction of reducing the first fluid chamber. Conversely, the fluid received by the second fluid chamber can be forced out by forcing fluid into the first fluid chamber under pressure, thereby exerting a force on the piston in the direction of reducing the second fluid chamber. In this embodiment of the spray gun according to the invention, thus, the pressurable gas-filled pressure chamber has been replaced by a fluid chamber. Instead of a pressurized gas in this case the pressure on the piston is exerted by the fluid located in the respective other fluid chamber, so that alternately the fluid is expelled from the two fluid chambers. This embodiment has the advantage that the pauses between two ejection processes of the spray gun are much shorter, since it is no longer necessary to wait until the fluid chamber is filled again in order to start with the next fluid ejection. The filling of the one fluid chamber causes namely, the fluid ejection through the other fluid chamber. According to a development of this embodiment of the spray gun according to the invention, a first sensor in the first fluid chamber and a second sensor in the second fluid chamber are provided. As explained above, a defined position of the piston, with which fluid is still present in the respective fluid chamber during the ejection process, can be detected by the sensor. Further, with the sensor, a fluid valve can be actuated, via which the fluid of the respective fluid chamber is ejected. By means of the sensor, the respective fluid valve is closed when the defined position of the piston has been detected.

According to a development of this embodiment of the spray gun according to the invention, the sensors are adjustable in the longitudinal direction of the cylinder. In this case, by adjusting the position of the sensors relative to the cylinder, the ejected fluid volume can be adjusted.

According to a further alternative embodiment of the spray gun according to the invention, this comprises a first and a second cylinder. In the first cylinder, a first fluid chamber is formed with a first cylinder opening, and in the second cylinder, a second fluid chamber is formed with a second cylinder opening. Further, in the first cylinder, a first pressure chamber and in the second cylinder, a second pressure chamber is formed, wherein the first and second pressure chambers communicate with each other and contain a non-compressible working fluid. The first fluid chamber is separated from the first pressure chamber by a first piston. The second fluid chamber is separated from the second pressure chamber by a second piston, wherein the volume of the first fluid chamber decreases as the volume of the second fluid chamber increases. Conversely, the volume of the first fluid chamber increases as the volume of the second fluid chamber decreases. According to this embodiment, the fluid received by the first fluid chamber can be pushed out by forcing fluid into the second fluid chamber under pressure, wherein a force is exerted on the second piston, which is transmitted to the first piston via the working fluid. Conversely, the fluid received by the second fluid chamber can be forced out by forcing fluid into the first fluid chamber under pressure, thereby exerting a force on the first piston which is transferred to the second piston via the working fluid.

In this embodiment, the fluid valve is coupled to the first cylinder opening and the second cylinder opening, wherein a fluid passage to the injection opening can be produced only to a respective cylinder opening. Furthermore, the fluid valve can preferably also be completely blocked.

Furthermore, in particular the first cylinder is associated with a first sensor, with which a defined position of the first piston, in which there is still fluid in the first fluid chamber during the ejection process, can be detected. With the first sensor, the fluid valve is actuated, wherein by means of the first sensor, the fluid valve for the passage from the first cylinder opening is closed to the injection port when the defined position of the first piston has been detected in the first cylinder. Furthermore, a second sensor is provided for the second cylinder, with which a defined position of the second piston, in which there is still fluid in the second fluid chamber during the ejection process, can be detected. With the second sensor, the fluid valve is actuated, wherein by means of the second sensor, the fluid valve is closed for passage from the second cylinder opening to the injection opening when the defined position of the second piston has been detected.

Also in this embodiment, the sensors may be adjustable in the longitudinal direction of the respective cylinder, so that by adjusting the positions of the sensors relative to the cylinders, the ejected fluid volume can be adjusted. Alternatively or additionally, in this embodiment, the volume of the working fluid in the two communicating pressure chambers can be changed. In this way, the maximum volume of the two fluid chambers and thus the ejected fluid volume can be adjusted.

Also in this further embodiment, the time interval between two ejection operations can be shortened, as is effected by the filling of a fluid chamber of the expulsion of the fluid from the other fluid chamber.

The spray gun according to the invention is suitable for the application of fluids (liquids). Suitable fluids for application generally have a dynamic viscosity in the range of 0.5 to 1000 mPa.s, often 0.8 to 500 mPa.s (determined by rotational viscometry according to Brookfield according to DIN53019 (ISO 3219) at 25 ° C and a Shear rate of 100 s ^-1 ). Suitable fluids may be Newtonian fluids or non-Newtonian fluid, the latter preferably being shear thinning, ie viscoelastic or pseudoplastic non-Newtonian fluids.

According to one embodiment, the spray gun according to the invention is designed for fluids with low viscosity, ie in particular for liquids having a viscosity of not more than 50 mPa.s, in particular not more than 30 mPa.s, for example 0.5 to 50 mPa.s, in particular 0.8 to 20 mPa.s (determined by Brookfield rotational viscometry according to DIN53019 (ISO 3219) at 25 ° C. and a shear rate of 100 s ^-1 ). These include both organic liquids, in particular solutions of active compounds, for example crop protection active ingredients, in organic solvents as well as aqueous liquids, for example aqueous active substance solutions but also emulsions, suspoemulsions and suspensions, wherein the active ingredient, in particular the crop protection active, is present in dispersed form in a coherent aqueous phase ,

The injection opening may be formed so that the fluid is atomized, but preferably a liquid jet is generated. For this purpose, the spray opening is preferably comprised of a spray nozzle which generates a jet of liquid upon passage of the liquid or aqueous solution, i. the liquid or solution is not atomized in particular.

According to a further embodiment, spray gun according to the invention is designed for gel-type fluids which, unlike the fluids with low viscosity, have an increased viscosity. Such gel-like fluids are generally viscoelastic and generally have a zero shear viscosity η ₀ of at least 100 mPa.s and in particular at least 200 mPa.s at 25 ° C. However, the dynamic viscosity of the gel-like fluid is usually a value of 1000 mPa.S, in particular 500 mPa.S and especially 300 mPa.s (determined by rotational viscometry according to Brookfield according to DIN53019 (ISO 3219) at 25 ° C and a shear rate of 100 s ^-1 ), and is in particular in the range of 30 to 1000 mPa.s, often in the range of 30 to 800 mPa.s and in particular in the range of 50 to 500 mPa.s. At 25 ° C., the limit value of the viscosity at an infinite shear gradient η _∞ is preferably not more than 300 mPa.s and in particular not more than 200 mPa.s. The gel-like liquid may be a gel formulation containing the active ingredient at the concentration required for the application. It is especially a liquid obtained by diluting a gel formulation to the concentration required for the application. In this case, the injection opening is preferably encompassed by a spray nozzle which generates a liquid jet upon passage of the gel-like fluid, ie the gel-like fluid can be applied in a punctiform manner, ie in the form of drops, or linearly, ie in the form of strands or bands. Examples of suitable spray nozzles are conical nozzles without baffle plate, jet nozzles or hole nozzles.

Examples of gel formulations which can be applied with the spray gun according to the invention in optionally diluted form are, in particular, those gel formulations which are used to combat arthropod pests. Such gel formulations are for example from WO 2008/031870 known. typically, These gels usually contain at least one active ingredient that is effective against arthropod pests such as insects or arachnids. In addition, these gels typically contain water, at least one thickener or gelling agent and optionally one or more attractant and / or feeding stimulants.

The spray guns described above are particularly suitable for the application of liquids containing one or more crop protection agents in dissolved or dispersed, i. suspended or emulsified form. The drug concentration in these fluids is typically in the range of 0.001 to 10 g / l. The use of the spray gun is not limited in this respect to certain crop protection agents and is suitable for the application of all active ingredients commonly used in crop protection, which are used in the form of liquid, including low viscosity or gelatinous forms of administration. These include in principle all crop protection active ingredients from the group of herbicides, herbicide safener, fungicides, insecticides, acaricides, nematicides, molluscicides, virucides, bactericides, algicides, growth regulators, pheromones, especially sex pheromones (mating disruptors) and activators and fertilizers.

• Wässrige Wirkstoffaufbereitungen von Wirkstoffen, insbesondere Pflanzenschutzwirkstoffen, die durch Verdünnen von Wirkstoffkonzentraten mit Wasser auf die gewünschte Anwendungskonzentration erhältlich sind und die einen oder mehrere der vorgenannten Pflanzenschutzwirkstoffe in gelöster oder dispergierter Form enthalten.
• Nicht-wässrige Lösungen oder Suspensionen von Wirkstoffen, insbesondere Pflanzenschutzwirkstoffen, die den Wirkstoff in einer für die Anwendung geeigneten Konzentration enthalten.
• Wässrige gelartige Flüssigkeiten, die einen oder mehrere Wirkstoffe, insbesondere Pflanzenschutzwirkstoffe, speziell aus der Gruppe der Insektizide, Akarizide oder Pheromone, enthalten und die bei geeigneter Viskosität als solche oder gegebenefalls nach Verdünnen mit Wasser auf die gewünschte Anwendungskonzentration appliziert werden und die einen oder mehrere der vorgenannten Pflanzenschutzwirkstoffe in gelöster oder dispergierter Form, sowie Wasser, wenigstens einen Verdicker oder Gelbildner und gegebenenfalls einen oder mehrere Lockstoff und/oder Fraßstimulantien enthalten.

The present invention further relates to the use of the spray gun described above for ejecting the following liquid products:

• Aqueous active ingredient preparations of active ingredients, in particular crop protection active ingredients, which are obtainable by diluting active substance concentrates with water to the desired use concentration and which contain one or more of the abovementioned crop protection active ingredients in dissolved or dispersed form.
• Non-aqueous solutions or suspensions of active substances, in particular crop protection agents, which contain the active substance in a concentration suitable for the application.
• Aqueous gel-like liquids which contain one or more active substances, in particular crop protection active ingredients, especially from the group of insecticides, acaricides or pheromones, and which are applied to the desired use concentration as such or, if appropriate, after dilution with water and which contain one or more of the aforementioned plant protection agents in dissolved or dispersed form, and water, at least a thickener or gelling agent and optionally one or more attractant and / or feeding stimulants.

The spray gun according to the invention can be used in a variety of fields of crop protection, in particular for the treatment of plants, especially of their leaves (foliar application), but also for the treatment of propagatable plant materials (seeds). The spray gun according to the invention is also suitable for the treatment of inanimate materials, especially inanimate organic materials such as wood, straw, paper, leather, textiles, plastic, which are infested with harmful organisms or should be protected from infestation with harmful organisms such as fungi or insects, with a liquid active ingredient composition containing one or more suitable active ingredients.

In addition, such materials can be hung as bait and loaded by the spray gun with a suitable formulation or reloaded.

The pesticide is sprayed with the spray gun in particular not as in a conventional application, but it is applied with a compact beam on the target surface. The application can be done on a single point (spot application) or cover a band from the forward motion. Due to the consistency of the pesticide, the applied quantities remain attached to the target surface. The crop protection agent therefore has in particular a gel consistency.

Figur 1

zeigt schematisch den Aufbau eines ersten Ausführungsbeispiels der erfindungsgemäßen Spritzpistole sowie die Kopplung dieser Spritzpistole mit einem Fluidreservoir und einem Druckgasbehälter,

Figur 2

zeigt schematisch den Aufbau eines zweiten Ausführungsbeispiels der erfindungsgemäßen Spritzpistole sowie die Kopplung dieser Spritzpistole mit einem Fluidreservoir und

Figur 3

zeigt schematisch den Aufbau eines dritten Ausführungsbeispiels der erfindungsgemäßen Spritzpistole sowie die Kopplung dieser Spritzpistole mit einem Fluidreservoir. Zunächst wird das erste Ausführungsbeispiel der erfindungsgemäßen Spritzpistole mit Bezug zu Fig. 1 erläutert:

In the following, embodiments of the spray gun according to the invention are explained in detail with reference to the drawings.

FIG. 1

shows schematically the structure of a first embodiment of the spray gun according to the invention and the coupling of this spray gun with a fluid reservoir and a compressed gas container,

FIG. 2

schematically shows the structure of a second embodiment of the spray gun according to the invention and the coupling of this spray gun with a fluid reservoir and

FIG. 3

schematically shows the structure of a third embodiment of the spray gun according to the invention and the coupling of this spray gun with a fluid reservoir. First, the first embodiment of the spray gun according to the invention with reference to Fig. 1 explains:

The spray gun includes a piston metering device having a cylinder 1 and a piston 2 movably supported in the cylinder 1. By the piston 2, the cylinder 1 is fluid-tightly divided into a fluid chamber 3 for the fluid to be ejected and a pressure chamber 4. In the fluid chamber 3, a first cylinder opening 5 is provided, through which the fluid chamber 3 can be filled with fluid and through which, moreover, fluid is forced out of the fluid chamber 3 during the ejection process. In the pressure chamber 4, a second cylinder opening 6 is formed in the cylinder 1, which is connected to a first port 7 for a compressed gas line 8, as will be explained later.

Furthermore, an opening is provided in the cylinder 1, through which the shaft 9 of the piston 2 passes and in which this shaft 9 is mounted in a gas-tight manner in a bearing 10. The storage takes place in such a way that the piston 2 can be reciprocated in the longitudinal direction of the cylinder 1, so that the volume of the fluid chamber 3 and the pressure chamber 4 is changed by the movement of the piston 2. Furthermore, seals are provided during storage, so that no compressed gas can escape from the pressure chamber 4 through this opening.

The part of the shaft 9 of the piston 2, which passes through the further opening in the cylinder 1, extends into a further cylinder 11. The rear end of the piston 2 is provided with a plate 12, which on the one hand the position of the piston. 2 for the user. For this purpose, the cylinder 11 is formed at least partially transparent. On the other hand, the plate 12 is used to couple the piston 2 with a compression spring 13, which is coupled on the one hand to the plate 12 and on the other hand to an end wall 15 of the cylinder 11. The compression spring 13 exerts on the piston 2 a force which acts in the direction of a reduction of the volume of the fluid chamber 3.

At the rear end of the cylinder 11, an adjusting device is further provided at the end wall 15, which limits the movement of the piston 2 in the direction of increasing the volume of the fluid chamber 3. The adjusting device thus sets the maximum volume of the fluid chamber 3. In the present embodiment, the adjusting device is designed as a screw 14 which is received in an internal thread of the end wall 15 of the cylinder 11. By turning the screw 14 in this internal thread, the length of the proportion of the screw 14, which extends into the cylinder 11, can be adjusted. Moves the piston 2 when filling the fluid chamber 3 with fluid, as will be explained later, in the direction of the screw 14, this movement of the piston 2 is limited by a stop of the plate 12 to the screw 14.

The volume of the cylinder may be, for example, in a range of 1 ml to 500 ml, in particular in a range of 5 ml to 50 ml. In the present embodiment, the cylinder 1 has a diameter of 25 mm. The maximum length over which the piston 2 is moved in the cylinder 1 in the longitudinal direction in a discharge operation is 25 mm. In this case, a maximum fluid volume of 12.27 cm ³ is pushed out through the first cylinder opening 5. The movement of the piston 2 of 1 mm in the direction of the first cylinder opening 5 thus causes 0.49 cm ^{3 of} fluid to be conveyed through the first cylinder opening 5.

To the piston 2 in the direction of the first cylinder opening 5, ie in Fig. 1 to the left, to be pressed, the gas pressure in the pressure chamber 4 is increased via the second cylinder opening 6. In the present embodiment, compressed air is introduced via the line 16 into the pressure chamber 4. The line 16 is connected to a compressed gas valve 17, whose function will be explained later.

The air pressure in the pressure chamber 4 is increased until the force exerted on the piston 2 by the compressed air and possibly the compression spring 13 in the direction of the first cylinder opening 5 exceeds the force which is in the opposite direction of the fluid which is located in the fluid chamber 3 is exerted on the piston 2. It should be noted that this drive pressure for the piston 2 can be exerted only by the compressed gas in the pressure chamber 4, only by the compression spring 13 or both of the compressed gas in the pressure chamber 4 and by the compression spring 13.

The first cylinder opening 5 is connected via a line 20 and a fluid valve 21 to a spray nozzle 22, which provides an injection opening. Through the injection opening, the fluid ejected from the spray gun exits in a fluid jet 23. For example, the pressure exerted on the fluid can be so great that the exiting fluid jet can be shot two to three meters onto a target surface. The pressure exerted on the fluid can be, for example, in a range from 2 bar to 6 bar.

The fluid to be ejected is conveyed into the fluid chamber 3 as follows: For a fluid reservoir 26, a fluid reservoir 24 is provided, which is connected via a line 25 to a port 32 of the spray gun. This connection 32 is coupled to a connection of the fluid valve 21, which is designed as a 3/2-way valve. The other ports of the 3/2-way valve are connected to the first cylinder port 5 and the spray nozzle 22. In the first position of the fluid valve 21, a fluid passage from the first cylinder port 5 to the spray nozzle 22 is provided. In a second position of the fluid valve 21, however, a fluid passage is provided from the fluid reservoir 24 via a conduit 25 through the fluid valve 21 to the conduit 20 and finally to the first cylinder port 5. In the second position of the fluid valve 21, a fluid 26, which is located in the fluid reservoir 24, can thus be conveyed into the fluid chamber 3. The fluid 26 can get into the fluid chamber 3 by gravity or a pump. In the present embodiment, however, the fluid reservoir 24 is pressurized with compressed air, which presses the fluid 26 into the fluid chamber 3. For this purpose, the fluid reservoir 24 is connected via a line 8 to a device 18 for providing compressed air. The device 18 may be, for example, a compressed air tank, a compressor and a hand pump. Furthermore, a shut-off valve 19 can optionally be arranged in the line 8.

The fluid reservoir 24 is further connected via a line 27 to the first port 7 of the compressed gas valve 17, which is also designed as a 3/2-way valve. In the first position of this compressed gas valve 17, a compressed gas passage is provided from the compressed air line 8 via the first port 7 through the compressed gas valve 17 and the line 16 to the second cylinder port 6 into the pressure chamber 4. In the second position of the compressed gas valve 17, however, this passage is closed and a compressed gas passage is provided by the conduit 16 via a third port 33 to the outside. In the second position, the pressure in the pressure chamber 4 can thus be reduced.

The fluid valve 21 and the compressed gas valve 17 may be electromagnetically actuated. They are connected to a control device 28, which can operate them. In this case, the valves 17 and 21 - as described above - be switched from the first position to the second position and vice versa. For this purpose, the control device 28 may comprise, for example, a relay or a microprocessor.

The controller 28 is further connected to a sensor 29. The sensor 29 may be formed for example as a reed switch or comprise a reed contact. This contact is closed when the field strength of a magnetic field at the sensor 29 exceeds a limit. The controller 28 detects whether the reed contact of the sensor 29 is closed or opened.

By means of the sensor 29, the position of the piston 2 in the cylinder 1 can be detected. In the spray gun according to the invention a certain position of the piston 2 is defined within the cylinder 1, in which the ejection operation is to be terminated. Exactly at this defined position of the piston 2, the sensor 29 changes its state. This is detected by the control device 28. In order to bring about this change of state of the sensor 29, a permanent magnet 30 is integrated in the piston 2. This permanent magnet 30 generates a magnetic field whose field strength at the location of the sensor 29 depends on the position of the piston 2. If the piston 2 is in the defined position described above, the magnetic field generated by the permanent magnet 30 causes a change of state in the sensor 29. If such a state change detected by the control device 28, the control device 28 actuates at least the fluid valve 21 such that the fluid passage is closed by the line 20 to the spray nozzle 22 and thus the fluid discharge is interrupted by the spray nozzle 22. The fluid valve 21 is thus switched to the second position. The position of the piston 2, at which this interruption takes place, is chosen so that before the interruption of the ejection still the full pressure of the piston 2 is exerted on the fluid in the fluid chamber 3. Hereby it is achieved that the expelled fluid jet 23 is still ejected at the same speed until the end of the ejection process, so that the fluid jet 23 is expelled coherently up to the desired destination.

In the defined position of the piston 2, in particular, there is still sufficient fluid in the fluid chamber 3 to transmit the pressure exerted by the piston 2 on the fluid through the conduit 20 to the spray nozzle 22. In the case of the above-mentioned dimensions of the cylinder 1, 1 ml to 1.5 ml of fluid are still present in the fluid chamber 3 at the defined position of the piston 2.

The control device 28 is further connected to a trigger 31, which is designed as an electrical push-button. When the trigger 31 is actuated, the control device 28 switches on the one hand, the fluid valve 21 in the first position in which fluid from the first cylinder opening 5 to the spray nozzle 22 passes, and on the other the compressed gas valve 21 in the first position, so that the pressure chamber 4 with Duckluft is applied and the fluid ejection is initiated.

In the following, the filling of the fluid chamber 3 and the fluid ejection in the first exemplary embodiment of the spray gun will be explained in detail.

When filling the fluid chamber 3 with fluid, both the fluid valve 21 and the compressed gas valve 17 are in the second position. In this case, the fluid 26 is conveyed in the fluid reservoir 24 through the conduit 25 and through the fluid valve 21 via the conduit 20 into the fluid chamber 3 of the cylinder 1. The pressure exerted by the compressed air pressure is so great that the piston 7 in Fig. 1 is moved to the right, against the force exerted by the compression spring 13. The air in the pressure chamber 4 escapes during the movement of the piston 2 through the conduit 16, the compressed gas valve 17 and the third port 33 to the outside. The fluid chamber 3 can be filled with fluid, wherein the volume of the fluid chamber 3 is increased by the movement of the piston 2 until the plate 12 of the piston 2 strikes the screw 14. The piston 2 is in this stop, the maximum set volume of the fluid chamber 3 is reached and the fluid chamber 3 is completely filled with fluid.

If the trigger 31 is then actuated by a user, a corresponding signal is transmitted to the control device 28. The control device 28 then switches the compressed gas valve 17 and the fluid valve 21 in the first position. In this position, the fluid supply is blocked by the fluid reservoir 24, the fluid passage from the fluid chamber 3 to the spray nozzle 22, however, is opened. In addition, the compressed gas passage is opened from the compressed air line 8 into the pressure chamber 4 simultaneously or preferably shortly before, so that compressed air is introduced into the pressure chamber 4. By the compressed air in the pressure chamber 4 and by the compression spring 13 such a large force is exerted on the piston 2, that this in Fig. 1 to the left, ie in the direction of a reduction of the volume of the fluid chamber 3, is moved. During this movement of the piston 2, the fluid in the fluid chamber 3 is expelled through the conduit 20, the fluid valve 21 and the spray nozzle 22 in a fluid jet 23. At this time, substantially constant pressure is maintained by the piston 2 in the fluid in the fluid chamber 3 throughout the ejection operation.

If the piston 2 now reaches the defined position described above, the permanent magnet 30 generates a magnetic field of a field strength in the sensor 29, which leads to a change of state of the sensor 29. Such a state change is detected by the control device 28, whereupon the control device 28 switches the fluid valve 21 and the compressed gas valve 17 back into the second position. The switching of the two valves 17 and 21 can take place simultaneously. Further, first, the fluid valve 21 can be switched and only shortly after the compressed gas valve 17. In any case, it is ensured that immediately before the switching of the fluid valve 21, the full force is still exerted by the piston 2 on the fluid located in the fluid chamber 3.

After the two valves 17 and 21 have been brought into the second position, as explained above, the fluid chamber 3 is automatically filled with fluid again for the next discharge operation.

• In dem zweiten Ausführungsbeispiel werden Teile, welche die gleiche Funktion wie im ersten Ausführungsbeispiel haben, mit denselben Bezugszeichen bezeichnet. Die Funktion dieser Teile ist auch dieselbe wie im ersten Ausführungsbeispiel, so dass die Beschreibung dieser Teile im Detail nicht wiederholt wird.

In the following, the second embodiment of the spray gun according to the invention with reference to Fig. 2 explains:

• In the second embodiment, parts having the same function as in the first embodiment are denoted by the same reference numerals. The function of these parts is also the same as in the first embodiment, so that the description of these parts will not be repeated in detail.

The second embodiment of the spray gun differs from the first embodiment in particular in that the pressure chamber 4 of the first embodiment has been converted into a second fluid chamber 34. In the cylinder 1 thus a first fluid chamber 3 and a second fluid chamber 34 is formed, which are separated from each other by the movable piston 2. Furthermore, the compression spring 13 of the first embodiment has been omitted.

As in the first embodiment, the first fluid chamber 3 is connected via the first cylinder opening 5 and a line 20 to a fluid valve 21, which is referred to as the first fluid valve 21 in this second embodiment. Also, the first fluid valve 21 is designed as a 3/2-way valve. As in the first embodiment, a port of the first fluid valve 21 is connected to the spray nozzle 22. However, in the second embodiment, a third fluid valve 35 is disposed between the port of the first fluid valve 21 and the spray nozzle 22, as will be explained later.

The port 32 of the first fluid valve 21 is connected as in the first embodiment with a fluid reservoir 24 in which fluid 26 is located. The fluid reservoir 24 can be acted upon by compressed air as in the first embodiment by means of the compressed air line 8, the shut-off valve 19 and the means 18 for providing compressed air. However, in all embodiments, the fluid may also be pressurized in other ways to move the piston 2 as explained later. For example, a pump can be used. In this case can a bypass may be provided, via which the fluid passes back into the reservoir when the cylinder 1 is not filled because at least one fluid valve or more fluid valves are closed.

Unlike the first embodiment, in the second embodiment, the second cylinder port 6, which in this case is arranged at the second fluid chamber 34, is connected via the line 16 to a second fluid valve 36. Also, this second fluid valve is designed as a 3/2-way valve. The connection 37 of the second fluid valve 36 is connected via a line 38 to the fluid reservoir 24. The other port 41 of the second fluid valve 36 is connected to the spray nozzle 22 via the third fluid valve 35.

The third fluid valve 35 is designed as a 3/3-way valve with locking middle position. Thus, a passage can be made from the conduit 39 to the spray nozzle 22 or from the conduit 40 to the spray nozzle 22. Furthermore, both passes can be disabled.

As in the first embodiment, a sensor 29 designed as a reed switch is arranged in the first fluid chamber 3, which is referred to as the first sensor 29 in the second embodiment. If the permanent magnet 30 of the piston 2 is in the defined position explained in the first exemplary embodiment, a magnetic field is generated by this permanent magnet 30 whose field strength at the location of the first sensor 29 causes the reed contact to be closed. This is detected by the control device 29.

In the second embodiment, however, in contrast to the first embodiment, a corresponding second sensor 39 is located at the second fluid chamber 34. Also, the second sensor 39 includes a reed contact. In the spray gun of the second embodiment, a further position of the piston 2 is defined, in which the ejection operation is to be terminated, namely in this case the ejection process of the fluid from the second fluid chamber 34. The second sensor 39 is formed so that the reed contact is closed when the permanent magnet 30 of the piston 2 generates a magnetic field at a correspondingly defined position, the field strength at the location of the second sensor 39 exceeds the limit for switching the reed contact. This state change of the second sensor 39 is also detected by the control device 28.

The two sensors 29, 39 may also be adjustable in the longitudinal direction of the cylinder 1. In this case, the fluid volume to be delivered can be adapted by changing the position of the sensors 29, 39.

• Vor dem eigentlichen Spritzvorgang wird der Zylinder 1 der Spritzpistole mit Fluid 26 aus dem Fluidreservoir 24 gefüllt. In diesem Ausgangszustand steuert die Steuervorrichtung 28 das dritte Fluidventil 35 zunächst so an, dass die Durchgänge in Richtung der Spritzdüse 22 gesperrt sind, das heißt, das dritte Fluidventil 35 befindet sich in der Mittelstellung. Daraufhin wird von der Steuervorrichtung 28 das erste Fluidventil 21 so angesteuert, dass sich ein Fluiddurchgang von dem Fluidreservoir 24 in die erste Fluidkammer 3 ergibt. Wird nun das Absperrventil 19 geöffnet, wird das Fluidreservoir 24 mit Druckluft beaufschlagt, so dass Fluid 26 über die Leitung 25 durch das erste Fluidventil 21 in die erste Fluidkammer 3 strömt. Alternativ kann auch in diesem Fall das Fluid unter Druck gesetzt werden, z. B. durch eine Pumpe. Dabei wird der Kolben 2 bei der Darstellung gemäß Figur 2 nach rechts bewegt, bis er an einen (nicht dargestellten) Anschlag anschlägt. Falls sich in diesem Fall noch Luft in der zweiten Fluidkammer 34 befindet, kann ein Auslassventil zum Verdrängen dieser Luft vorgesehen sein. Befindet sich in der zweiten Fluidkammer 34 bereits Fluid 26, wird das zweite Fluidventil 36 von der Steuervorrichtung 28 so angesteuert, dass der Fluiddurchgang zwischen der Leitung 38 und der Leitung 16 geöffnet ist, so dass das in der zweiten Fluidkammer 34 enthaltene Fluid zurück in das Reservoir 24 strömen kann.

Hereinafter, the spraying operation with the spray gun according to the second embodiment will be explained.

• Before the actual injection process, the cylinder 1 of the spray gun is filled with fluid 26 from the fluid reservoir 24. In this initial state, the control device 28 initially controls the third fluid valve 35 so that the passages are blocked in the direction of the spray nozzle 22, that is, the third fluid valve 35 is in the middle position. The first fluid valve 21 is then actuated by the control device 28 such that a fluid passage from the fluid reservoir 24 into the first fluid chamber 3 results. If now the shut-off valve 19 is opened, the fluid reservoir 24 is supplied with compressed air, so that fluid 26 flows through the line 25 through the first fluid valve 21 into the first fluid chamber 3. Alternatively, in this case, the fluid can be pressurized, for. B. by a pump. In this case, the piston 2 in the illustration according to FIG. 2 moves to the right until it hits a stop (not shown). If there is still air in the second fluid chamber 34 in this case, an outlet valve for displacing this air may be provided. If fluid 26 is already present in the second fluid chamber 34, the second fluid valve 36 is actuated by the control device 28 so that the fluid passage between the conduit 38 and the conduit 16 is opened, so that the fluid contained in the second fluid chamber 34 returns to the second fluid chamber 34 Reservoir 24 can flow.

Now, when the trigger 31 is actuated by a user, the control device 28 switches the first fluid valve 21 for a fluid passage from the line 20 into the line 39. The fluid passage from the line 20 into the line 25 is blocked. The second fluid valve 36, however, is switched so that the fluid passage is opened from the line 38 into the line 16, the fluid passage is blocked from the line 16 into the line 40, however. Further, the controller 28 controls the third fluid valve 35 so that the fluid passage from the conduit 39 to the spray nozzle 22 is opened, the fluid passage from the conduit 40 to the spray nozzle 22, however, is locked. This switching of the three fluid valves 21, 36 and 35 causes by the pressurization of the fluid reservoir 24 with compressed air fluid 26 via the line 38 through the second fluid valve 36 into the second fluid chamber 34 flows. The fluid in the second fluid chamber 34 exerts a force on the piston 2, so that this in the direction of a reduction of the volume of the first fluid chamber 3 in the illustration according to figure 2 is pressed to the left. Thus, the fluid in the first fluid chamber 3 is forced through the first cylinder port 5 via the conduit 20, through the first fluid valve 21 via the conduit 39 and through the third fluid valve 35 to the spray nozzle 22 where it is ejected as the fluid jet 23.

The ejection process lasts until the magnetic field generated by the permanent magnet 30 at the location of the first sensor 29 exceeds a field strength at which a state change of the first sensor 29 is brought about, which is detected by the control device 28. Once this state change has been detected, the control device 28 switches the three fluid valves 21, 36 and 35 as follows: The first fluid valve 21 is switched so that the passage from line 20 to line 39 is blocked, the passage from line 25 to Line 20, however, is opened. The second fluid valve 36 is switched so that the fluid passage is blocked by the line 38 in the conduit 16, the fluid passage from the conduit 16 into the conduit 40, however, is opened. Further, the third fluid valve 35 is switched so that it is brought into the fully locking center position or that it is brought directly to a position in which the fluid passage from the conduit 40 to the spray nozzle 22 is opened, the fluid passage from the conduit 39 to the spray nozzle 22 is locked. When the defined position of the piston 2 has been detected, at least the first fluid valve 21 or the third fluid valve 35 is blocked for passage from the first fluid chamber 3 to the spray nozzle 22.

This switching of the three fluid valves 21, 36, 35 causes the other way round, the fluid 26 flows under pressure via the line 25, through the first fluid valve 21 into the first fluid chamber 3. Here, the fluid exerts a force on the piston 2, so that this in the direction of a reduction of the volume of the second fluid chamber 34 in the illustration according to FIG. 2 is moved to the right. Now, the first fluid chamber 3 is filled. By this filling, however, the fluid contained in the second fluid chamber 34 is forced via the line 16, through the second fluid valve 36, via the line 40, through the third fluid valve 35 to the spray nozzle 22 at which it is ejected in a fluid jet 23.

This ejection process lasts until the magnetic field generated by the permanent magnet 30 at the location of the second sensor 39 reaches a field strength which causes a change of state of the second sensor 39. As soon as such a state change has been detected by the control device 28, the fluid valves 21, 36 and 35 are switched back again as explained above, so that subsequently the second fluid chamber 34 is filled and thereby the fluid in the first fluid chamber 3 is ejected as a fluid jet 23.

These ejections, for example, as long as the user has pressed the trigger 31. When the user releases the trigger 31, the currently executing ejection operation is terminated, whereupon the third fluid valve 35 is brought into the fully-locking middle position. Alternatively, a single ejection operation could be performed upon depression of the trigger 31. The next ejection process is then triggered only after repeated actuation of the trigger 31.

The fluid is ejected from the spray gun of the second embodiment, as in the spray gun of the first embodiment, as a fluid jet 23 having a constant ejection velocity until the end of the ejection operation, so that the fluid jet 23 fully reaches its target. In addition, the switching of the fluid valves 21, 36 and 35 prevents dripping of fluid.

• In dem dritten Ausführungsbeispiel werden Teile, welche die gleiche Funktion wie im ersten bzw. zweiten Ausführungsbeispiel haben, mit denselben Bezugszeichen bezeichnet. Die Funktion dieser Teile ist auch dieselbe wie im ersten bzw. zweiten Ausführungsbeispiel, so dass die Beschreibung dieser Teile im Detail nicht wiederholt wird.
• Die prinzipielle Funktionsweise der Spritzpistole des dritten Ausführungsbeispiels entspricht der Spritzpistole des zweiten Ausführungsbeispiels. Allerdings ist in diesem Fall nicht ein einziger Zylinder 1 vorgesehen, welcher zwei Fluidkammern 3 und 34 enthält, die durch den Kolben 2 getrennt sind, sondern es sind zwei Zylinder 1-1 und 1-2 vorgesehen. Das Funktionsprinzip entspricht jedoch im Wesentlichen dem Funktionsprinzip der Spritzpistole des zweiten Ausführungsbeispiels.

In the following, the third embodiment of the spray gun according to the invention with reference to Fig. 3 explains:

• In the third embodiment, parts having the same function as in the first and second embodiments are denoted by the same reference numerals. The function of these parts is also the same as in the first or second embodiment, so that the description of these parts will not be repeated in detail.
• The basic operation of the spray gun of the third embodiment corresponds to the spray gun of the second embodiment. However, in this case, not a single cylinder 1 is provided which includes two fluid chambers 3 and 34 separated by the piston 2, but two cylinders 1-1 and 1-2 are provided. However, the operating principle substantially corresponds to the operating principle of the spray gun of the second embodiment.

In the first cylinder 1-1, a first fluid chamber 3-1 is formed with a first cylinder opening 5-1. Furthermore, a first pressure chamber 4-1 is formed in the first cylinder 1-1. Between the first fluid chamber 3-1 and the first pressure chamber 4-1, a movable first piston 2-1 is arranged.

Accordingly, in the second cylinder 1-2, a second fluid chamber 3-2 is formed with a second cylinder opening 5-2. Also in the second cylinder 1-2, a second pressure chamber 4-2 is formed, wherein a movable second piston 2-2 between the second fluid chamber 3-2 and the second pressure chamber 4-2 is arranged. The first pressure chamber 4-1 and the second pressure chamber 4-2 communicate with each other via a line 42. In the first and second pressure chambers 4-1, 4-2 and the line 42 is a non-compressible working fluid, such as oil. Further, the conduit 42 may be connected to a reservoir 43 for the working fluid. Via the reservoir 43, the volume of the working fluid in the two pressure chambers 4-1, 4-2 and the line 42 can be changed. In this way, the maximum volume of the two fluid chambers 3-1, 3-2 and thus the ejected fluid volume can be adjusted.

Alternatively or additionally, as in the spray gun of the second embodiment, the two sensors 29-1, 29-2 in the longitudinal direction of the cylinder 1-1, 1-2 be adjustable, so that the auszubringende fluid volume can be adjusted by the position of the sensors 29-1, 29-2 is changed.

The working fluid transmits a force exerted by the first piston 2-1 to the second piston 2-2 and vice versa. The unit formed by the first piston 2-1, the working fluid and the second piston 2-2 thus corresponds to the piston 2 of the spray gun of the second embodiment.

The spray gun of the third embodiment comprises two fluid valves 44 and 45. The fluid valve 44 is also referred to below as the first fluid valve 44. Since the fluid valve 45 of the function corresponds to the third fluid valve 35 of the second embodiment, this fluid valve 45 is also referred to below as the third fluid valve 45.

The first cylinder opening 5-1 of the first fluid chamber 3-1 is connected via a line 46 to a port of the first fluid valve 44 and the third fluid valve 45. Further, the second cylinder port 5-2 of the second fluid chamber 3-2 is connected via a line 47 to another port of the first fluid valve 44 and another port of the third fluid valve 45. Another connection of the first fluid valve 44 is coupled via a line 25 to the fluid reservoir 24, in which the fluid 26 is located. As in the first two embodiments, the fluid reservoir 24 is coupled via a compressed air line 8, an optional shut-off valve 19 to a device 18 for providing compressed air. However, it would also be possible - as described in the spray gun of the second embodiment -, the fluid directly, for. B. by a pump under pressure to set. The first fluid valve 44 is actuated by the control device 28. In a state of the first fluid valve 44 a passage is provided from line 25 to line 46, the passage from line 25 to line 47 being disabled. In the other state, passage is provided from line 25 to line 47, with the passage from line 25 to line 46 disabled.

Also, the third fluid valve 45 is driven by the control device 28, wherein in one state, a passage from the conduit 46 to the spray nozzle 22 is opened, whereas the passage from the conduit 47 to the spray nozzle 22 is blocked. In another condition, the passage from the conduit 46 to the spray nozzle 22 is blocked, whereas the passage from the conduit 47 to the spray nozzle 22 is opened. Further, as in the spray gun of the second embodiment, a center position is provided in which both passages to the spray nozzle 22 are blocked.

Analogous to the spray guns of the first two embodiments, a first sensor 29-1 is provided for the first cylinder 1-1 in the first fluid chamber 3-1, which detects the position of the first piston 2-1 due to one generated by a first permanent magnet 30-1 Magnetic field recorded. Similarly, in the second fluid chamber 3-2 of the second piston 1-2, a second sensor 29-2 is provided which detects the position of the second piston 2-2 by, as explained in the second embodiment, a state change of the second sensor 29-2 is detected by the field strength of a magnetic field, which is generated by a second permanent magnet 30-2, which is arranged in the second piston 2-2. The signals of the two sensors 29-1 and 29-2 are transmitted to the control device 28, as in the spray gun of the second embodiment, which control the two fluid valves 44 and 45 in response to these signals.

As in the spray gun of the second embodiment, the fluid volume to be delivered can be adjusted by the positioning of the two sensors 29-1, 29-2 in the longitudinal direction of the cylinders 1-1, 1-2.

• Der Fluidausstoß wird wie bei den beiden vorhergehenden Ausführungsbeispielen dadurch initiiert, dass ein Nutzer den Auslöser 31 dauerhaft oder pro Ausstoßvorgang einmal betätigt, welcher mit der Steuervorrichtung 28 verbunden ist.

Hereinafter, an injection operation performed by the spray gun of the third embodiment will be explained.

• The fluid ejection is initiated as in the two previous embodiments in that a user actuates the trigger 31 permanently or per ejection process, which is connected to the control device 28.

Initially, the controller 28 controls the first fluid valve 44 so as to provide fluid passage from the conduit 25 to the conduit 46 such that the first one of the first and second fluid valves 44 and 44 is in fluid communication Fluid chamber 3-1 can be filled with fluid 26. The third fluid valve 45 is initially in the middle position, in which the two passages are blocked. The first fluid chamber 3-1 is filled with fluid, whereby the piston 2-1 in the illustration according to FIG. 3 is moved to the right, so that increases the volume of the first fluid chamber 3-1. At the same time, the second piston 2-2 moves by the power transmission through the working fluid as shown in FIG FIG. 3 to the left in the direction of reducing the volume of the second fluid chamber 3-2. If there is still air in the second fluid chamber 3-2 when the spray gun is started up, an outlet valve (not shown) can be provided for this air. The first piston 2-1 is moved so far in the direction of increasing the volume of the first fluid chamber 3-1 until the first piston 2-1 abuts against a stop which can be provided by a cylinder wall or - as in the spray gun of the first Embodiment - of an adjusting screw. Thereafter, the controller 28 switches the first fluid valve 44 to provide fluid passage from the conduit 25 to the conduit 47. Further, the third fluid valve 45 is switched so that a fluid passage from the conduit 46 to the spray nozzle 22 is opened.

By the pressurization of the fluid reservoir 24, the fluid 26 is now forced through the first fluid valve 44 and the conduit 47 into the second fluid chamber 3-2. Alternatively, as in the spray gun of the second embodiment, the fluid z. B. be pressurized by a pump. As a result, the second piston 2-2 is moved in the direction of increasing the volume of the second fluid chamber 3-2. At the same time by the communication of the two pressure chambers 4-1 and 4-2 of the first piston 2-1 is moved in the direction of reducing the volume of the first fluid chamber 3-1, whereby fluid from the first fluid chamber 3-1 via the line 46, through the third fluid valve 45 is pushed through to the spray nozzle 22 where it is ejected as a fluid jet 23.

When the first piston 2-1 has reached the defined position, which is detected by the first sensor 29-1 as explained above, the control device 28 switches the third fluid valve 45 such that the fluid passage from the line 46 to the spray nozzle 22 is blocked is. The third fluid valve 45 is brought in this case, in particular in the fully locking center position. Thereafter, the first fluid valve 44 is switched so that a fluid passage from the conduit 25 to the conduit 46 is opened. Now, the third fluid valve 45 is brought to a position at which a passage from the conduit 47 to the spray nozzle 22 is provided. It is now by the pressurization of the fluid reservoir 24 fluid 26 through the first fluid valve 44 and the line 46 is pressed into the first fluid chamber 3-1. As a result, the first piston 2-1 is moved in the direction of increasing the volume of the first fluid chamber 3-1. At the same time, the second piston 2-2 is moved in the direction of decreasing the volume of the second fluid chamber 3-2, whereby the fluid in the second fluid chamber 3-2 is forced through the conduit 47 and through the third fluid valve 45 to the spray nozzle 22 in which it is ejected as a fluid jet 23. If, as explained above, the second piston 2-2 has reached the defined position within the second cylinder 1-2, this is detected by the second sensor 29-2. Thereafter, the control device 28 controls the two fluid valves 44 and 45 again so that the ejection operation of the fluid from the second fluid chamber 3-2 is interrupted, the second fluid chamber 3-2 is refilled and thereby another ejection operation of the first in the first fluid chamber. 3 -1 fluid begins.

The spray guns described above are used in particular for ejecting liquids. The liquids contain in particular at least one active ingredient for crop protection.

LIST OF REFERENCE NUMBERS

1

cylinder

1-1

first cylinder

1-2

second cylinder

2

piston

3

Fluid chamber; first fluid chamber

3-1

first fluid chamber

3-2

second fluid chamber

4

pressure chamber

4-1

first pressure chamber

4-2

second pressure chamber

5

first cylinder opening

5-1

first cylinder opening

5-2

first cylinder opening

6

second cylinder opening

7

first connection

8th

Compressed air line

9

Shaft of the piston 2

10

camp

11

cylinder

12

plate

13

compression spring

14

screw

15

end wall

16

management

17

Pressure gas valve

18

Device for providing compressed air

19

shut-off valve

20

management

21

Fluid valve; first fluid valve

22

nozzle

23

fluid jet

24

fluid reservoir

25

management

26

fluid

27

management

28

control device

29

Sensor; first sensor

30

permanent magnet

31

trigger

32

second connection

33

third connection

34

second fluid chamber

35

third fluid valve

36

second fluid valve

37

connection

38

management

39

management

40

management

41

connection

42

management

43

reservoir

44

Fluid valve; first fluid valve

45

Fluid valve; third fluid valve

46

management

47

management

Claims (15)

1. A spray gun for the expulsion of a fluid, with

   - at least one cylinder (1) in which a piston (2) is mounted movably, the cylinder (1) having formed in it a fluid chamber (3), the volume of which can be varied by means of a movement of the piston (2) and in which at least one first cylinder orifice (5) is formed, and

   - a spray orifice which is connected to the first cylinder orifice (5) of the cylinder (1) via a connecting line (20), so that a fluid, which is received by the fluid chamber (3) and is pressed out through the first cylinder orifice (5) by means of the pressure exerted by the piston (2), arrives via the connecting line (20) at the spray orifice and is expelled there,

   wherein

   - a fluid valve (21) is arranged in the connecting line (20), and

   - in the cylinder (1) a sensor (29) is provided, by means of which a defined position of the piston (2), in which fluid is still located in the fluid chamber (3) during the expulsion operation, can be detected, and by means of which the fluid valve (21) can be actuated, the fluid valve (21) being closed by means of the sensor (29) when the defined position of the piston (2) has been detected.
2. The spray gun according to claim 1,
   wherein
   the defined position of the piston (2) is detected by the sensor (29) by means of a magnetic field generated or varied by the piston (2).
3. The spray gun according to one of the preceding claims,
   wherein,
   furthermore, the cylinder (3) has formed in it a pressure chamber (4), in which is formed at least one second cylinder orifice (6) which is connected to a first connection (7) for a compressed gas line (8) .
4. The spray gun according to one of the preceding claims,
   wherein
   the spray gun has a second connection (32) for a fluid reservoir (24), which connection is connected to the first cylinder orifice (5) and via which fluid can be conveyed into the fluid chamber (3).
5. The spray gun according to claim 4,
   wherein
   the fluid valve (21) is a first 3/2-way valve, in which, in a first setting, a passage of fluid from the first cylinder orifice (5) to the spray orifice is provided, and, in a second setting, a passage of fluid from the second connection (32) to the first cylinder orifice (5) is provided.
6. The spray gun according to claim 3, 4 or 5,
   wherein
   between the first connection (7) and the second cylinder orifice (6), a compressed gas valve (17) designed as a second 3/2-way valve is arranged, in which, in a first setting, a passage of compressed gas from the first connection (7) to the second cylinder orifice (6) is provided, and, in a second setting, a passage of compressed gas from the second cylinder orifice (6) into the open is provided.
7. The spray gun according to claim 6,
   wherein
   the sensor (29) is coupled to the first and the second 3/2-way valve, and the sensor (29) switches the first and the second 3/2-way valve into the second setting when the piston (2) is in the defined position, so that the expulsion of fluid through the spray orifice is interrupted and fluid is conveyed by means of the compressed gas from the fluid reservoir (24) into the fluid chamber (3) via the first 3/2-way valve (21).
8. The spray gun according to claim 6 or 7,
   wherein
   the spray gun has a trigger (31) which is coupled to the first and the second 3/2-way valve and which, when actuated, switches the first and the second 3/2-way valve into the first setting, so that the piston (2) is moved by the compressed gas in the pressure chamber (4), such that the volume of the fluid chamber (3) is reduced and fluid is expelled through the spray orifice.
9. The spray gun according to one of the preceding claims,
   wherein
   the spray gun has a regulating device (14, 15), by means of which the movement of the piston (2) in the cylinder (1) and, consequently, the maximum volume of the fluid chamber (3) can be limited.
10. The spray gun according to claim 1 or 2
    wherein

    - a first and a second fluid chamber (3, 34) are formed in the cylinder (1), and at least the first cylinder orifice (5) is formed in the first fluid chamber (3) and at least one second cylinder orifice (6) is formed in the second fluid chamber (34),

    - the fluid received by the first fluid chamber (3) can be pressed out by fluid being pressed under pressure into the second fluid chamber (34), with the result that force is exerted upon the piston (2) in the direction of a reduction in the size of the first fluid chamber (3), and

    - the fluid received by the second fluid chamber (34) can be pressed out by fluid being pressed under pressure into the first fluid chamber (3), with the result that force is exerted upon the piston (2) in the direction of a reduction in the size of the second fluid chamber (34).
11. The spray gun according to claim 1 or 2,
    wherein

    - the spray gun comprises a first and a second cylinder (1-1, 1-2),

    - in that a first fluid chamber (3-1) with a first cylinder orifice (5-1) is formed in the first cylinder (1-1) and a second fluid chamber (3-2) with a second cylinder orifice (5-2) is formed in the second cylinder (1-2),

    - in that a first pressure chamber (4-1) is formed in the first cylinder (1-1) and a second pressure chamber (4-2) is formed in the second cylinder (1-2), the first and the second pressure chamber (4-1, 4-2) communicating with one another and comprising a non-compressible working fluid,

    - the first fluid chamber (3-1) is separated from the first pressure chamber (4-1) by a first piston (2-1), and the second fluid chamber (3-2) is separated from the second pressure chamber (4-2) by a second piston (2-2), the volume of the first fluid chamber (4-1) decreasing when the volume of the second fluid chamber (4-2) increases,

    - the fluid received by the first fluid chamber (3-1) can be pressed out by fluid being pressed under pressure into the second fluid chamber (3-2), with the result that force is exerted upon the second piston (2-2) and is transmitted to the first piston (2-1) via the working fluid, and

    - the fluid received by the second fluid chamber (3-2) can be pressed out by fluid being pressed under pressure into the first fluid chamber (3-1), with the result that force is exerted upon the first piston (2-1) and is transmitted to the second piston (2-2) via the working fluid.
12. The spray gun according to one of the preceding claims,
    wherein
    the fluid is a liquid, and the spray orifice is surrounded by a spray nozzle (22) which, when the liquid passes through it, generates a liquid jet (23) .
13. The use of the spray gun according to one of the preceding claims for the expulsion of liquid plant protectants.
14. The use according to claim 13, the liquid plant
    protectant being a gel-like liquid.
15. The use according to claim 14, the liquid containing
    at least one active substance which is suitable for combating arthropodic pests.

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