Device for dispensing spray or fog substances with a oscillating flame burner and fog tube for such a device

Abstract

Device for discharging smoke substances, with a oscillating flame burner to which a resonator (2) is connected, into which a supply line (9) for the smoke substance opens and which projects into a first tube (3) of a smoke tube (10), wherein the smoke tube (10) has at least three further tubes (4, 5, 6) which, forming annular channels (32, 33), project axially beyond the respective inner tube, characterized in that the third tube (5) is provided with at least one intake opening (24) located in its wall for larger smoke substance droplets (35) located in the radially outer annular channel (33).

Description

[0001] The invention relates to a device for dispensing spray or fog substances, comprising a oscillating flame burner according to the preamble of claim 1 and a fog tube for such a device according to the preamble of claim 18.

[0002] These devices are used to dispense active ingredients (preparations) with various carrier substances. The carrier substance serves to disperse the active ingredient, for example, insecticides, fungicides, pesticides, or disinfectants, in fog form (aerosols). Water is frequently used as the carrier substance. The use of aqueous active ingredient mixtures (preparation mixtures), hereinafter referred to as fog substance, with water as the carrier substance is problematic when a conventional fogging tube is used. When fogging with such a tube, a very broad droplet spectrum is produced with a high proportion of large, non-sustainable droplets.

[0003] US Patent 2,857,332 A describes a conventional device for dispersing liquids in air or other gases to produce mist, comprising a resonant pulse-jet combustion unit and an outlet tube. The end of the outlet tube is surrounded by a sleeve that supports several converging conical elements of increasing diameter and the section of the device's housing that expands beyond a constriction. These elements act as a multi-stage air intake, drawing in ambient air through the action of the pulse-jet exhaust gases from the combustion unit.

[0004] DE 31 48 522 A1 describes an atomizer driven by a combustion unit operating on the pulse-jet principle, which uses a carburetor to supply the combustion chamber of the combustion unit with atomized fuel. In the carburetor, overpressure is supplied to a secondary chamber with a wall formed by a diaphragm in order to close a fuel inlet valve during the start-up phase of the combustion unit. Fuel delivery to the carburetor under overpressure is achieved by using the combustion pressure pulses of the combustion unit as the fuel pump drive.

[0005] US 2,595,759 A concerns liquid spray nozzles in which an auxiliary fluid, such as air or steam, is used to facilitate the atomization process, especially nozzles used to inject fuel into the combustion chamber of a gas turbine in a power plant.

[0006] US Patent 6,389,815 B1 discloses and describes a two-stage fuel nozzle arrangement for a gas turbine engine. The primary combustion zone is centrally located and includes a fuel injector surrounded by one or more swirl chambers to provide a fuel-air mixture that is ignited to define a first-stage combustion zone. A secondary combustion zone is provided by an annular housing surrounding the primary combustion zone. It includes a secondary fuel injector with a radially outward-facing opening surrounded by a ring containing openings to provide a swirl chamber for the secondary combustion zone. Cooling air is directed at an angle between the primary and secondary combustion zones to retard mixing.

[0007] The invention is based on the objective of designing the generic device and the generic fogging tube in such a way that flawless atomization of the water with the active ingredient is ensured.

[0008] This problem is solved according to the invention in the generic device for dispensing spray and fog substances with the characterizing features of claim 1 and in the generic fog tube with the characterizing features of claim 18.

[0009] The device according to the invention has a fogging tube suitable for discharging aqueous fogging agents, comprising at least four tubes that are partially nested within each other to form annular channels. This arrangement aims to generate only airborne droplets (aerosols) and to exclude large, non-airborne droplets. Should larger droplets form at the end of the third tube during atomization, they fall onto the protruding part of the fourth tube and are thus collected. In this way, the droplet size distribution can be kept within narrow limits. Consequently, the flow rate (liters per hour) of the water-based fogging agent can be significantly increased while still achieving optimal atomization with a good aerosol droplet spectrum. Naturally, additional tubes can be provided if required.

[0010] The third pipe is advantageously equipped with at least one intake opening for larger fog droplets located in the annular channel. The exhaust cooling air flowing at high velocity through the fog pipe creates a negative pressure in the annular channel via the intake opening of the third pipe. The larger droplets captured by the fourth pipe are thereby drawn into the annular channel and pass through the intake opening into the third pipe. Here, they are carried along by the exhaust cooling air flow and broken up.

[0011] In the case of additional pipes, it is advantageous for each subsequent pipe to be provided with at least one suction opening for the drops exiting in the previous pipe.

[0012] Further features of the invention will become apparent from the further claims, the description and the drawings.

[0013] The invention is explained in more detail below with reference to an embodiment illustrated in the drawings. It shows Fig. 1 in axial section a fog tube according to the invention, which is mounted on a resonator and a cooling tube of a fog machine, Fig. 2 the fog tube according to Fig. 1 without the resonator in a representation accordingly Fig. 1. Fig. 3 schematically shows the droplet distribution during nebulization with the device according to the invention.

[0014] The in the Fig. 1 and Fig. The fog tube 10 shown in Figure 2 is a high-performance fog tube that is mounted on a resonator 2 and a cooling tube 7. The resonator 2 is a cylindrical tube that forms an extension of a oscillating flame burner. Near its end furthest from the resonator 2, a feed line opens into the oscillating flame burner, through which fuel, preferably gasoline, is supplied from a tank that is part of the fog machine. The gasoline is burned in the oscillating flame burner, and the combustion of the gasoline produces regular deflagrations that cause the gas column in the resonator or oscillating tube 2 to oscillate.

[0015] Into this oscillating gas stream, near the front end of the resonator tube 2, the fog substance is introduced via a feed line 9 and broken down into the finest particles. The feed line 9 is provided in a connector 8, which projects through an opening 11 in the tube 4 and extends to the resonator 2. The connector 8 has an opening 34 through which the feed line 9 projects into the resonator 2, preferably to about half its cross-sectional height. One end of the tube 3 rests against the connector 8.

[0016] The fogging agent consists of a mixture of an active ingredient, typically an active ingredient formulation, e.g., an insecticide, pesticide, fungicide, or disinfectant, with a carrier substance, which in this example is preferably water. The fogging agent is contained in an active ingredient tank (not shown), from which it is conveyed in a known manner. The fogging agent, processed into a suspended aerosol fog, then emerges from the fogging tube 10, which is formed by the vibrating flame burner, the resonator 2, and the cooling tube 7.

[0017] The cooling tube 7 surrounds the oscillating flame burner and the resonator 2 at a distance and runs coaxially to them. Primary cooling air is drawn in through at least one opening at the end of the cooling tube 7 facing away from the resonator 2 during operation of the fog machine. This air is drawn in by the exhaust gas flowing at high velocity from the resonator 2 due to the resulting negative pressure. This primary cooling air then flows in the annular space 25 between the oscillating flame burner and the resonator 2 in the direction of arrow 26. Fig. 1. This cooling airflow cools the wall of resonator 2 and the resonator combustion chamber. The primary cooling air mixes with the exhaust gas-fog mixture exiting the outlet of resonator 2. This mixing reduces the temperature of the fog-exhaust gas-air mixture.

[0018] The fogging device is primarily used in the healthcare sector to combat malaria, dengue fever, and other mosquito-borne diseases, as well as to control flying and crawling insects; in agriculture for plant protection measures in plantations and greenhouses; and in stored product protection for pest control in warehouses and silos, and for inhibiting potato sprouting. Further applications include disinfection measures in human care, animal husbandry, and food production.

[0019] The resonator 2 projects axially from the cooling tube 7. The fog tube 10 has a first tube 3, which is surrounded at a distance by a second tube 4 of the fog tube 10. The second tube 4 projects beyond the first tube 3 at both ends. The second tube 4 is pushed onto the cooling tube 7 by its protruding end 16.

[0020] The inner first tube 3 is held within the second tube 4 by a spacer 12. The spacer 12 is advantageously star-shaped and has, for example, three arms 27 distributed around its circumference, each having bearing surfaces on its radial inner and outer surfaces 28, 29, with which the arms 27 rest on the resonator 2 or abut the inner surface of the second tube 4. In this way, the tube 3 is perfectly aligned with respect to the resonator 2 and the tube 4. The tubes 2 to 4 are coaxial with each other. An annular channel 30 is formed between the resonator 2 and the tube 3, and an annular channel 31 is formed between the two tubes 3 and 4.

[0021] A tube 5 is attached to the tube 4. It is significantly shorter than the tube 4 and sits on the tube 4 with a reduced-diameter end section 19. To prevent air from being drawn in between the end section 19 and the tube 4 during operation of the fog machine, the end section 19 rests against the outside of the tube 4. This can be easily achieved by sealing the connection to prevent air from being drawn in between the end section 19 and the tube 4 during operation of the fog machine. The tube 5 surrounds the tube 4 at a distance, so that an annular channel 32 is formed between the two tubes 4 and 5. The tube 5 projects axially beyond the tube 4. The annular channel 32 tapers over a short axial length at the transition to the annular end section 19. A tube 6, which also has a reduced-diameter end section 29, is attached to the tube 5 and projects axially beyond the tube 5.The end section 20 sits on the tube 5, preferably by means of a weld, so that no air is drawn in between the end section 20 and the tube 5 during use of the fog machine.

[0022] Between the two tubes 5, 6 a ring channel 33 is formed, which tapers over a small axial length at the transition to the annular end section 20.

[0023] In the described embodiment, the fog tube 10 is designed with four stages, the four stages being formed by the coaxially arranged tubes 3 to 6. Depending on the application of the fog machine, the fog tube 10 can have further stages, each formed by tubes designed and attached in accordance with tubes 5 and 6. Stages 3 to 6 are coordinated to achieve optimal fog delivery. Since the internal cross-section increases from the resonator 2 to the tube 6, the flow velocity v1 to v4 of the exhaust gas-fog-cooling air mixture decreases accordingly. The mixture has its highest flow velocity at the exit of the resonator 2 and its lowest at the exit of the tube 6.

[0024] This gradation of flow velocities v1 to v4 is matched to the length of the protruding parts of the pipes 3 to 6 and / or to the outlet area of ​​the annular channels 30 to 33 and / or to the volume of the pipes 3 to 6. The cross-sectional areas and volumes of the pipes 3 to 6 are also matched to achieve a large discharge rate of the fogging agent with the smallest possible formation of large, non-sustainable droplets.

[0025] Fig. Figure 3 shows the approximate droplet distribution in the emitted fog. The dashed line represents the droplet spectrum of conventional fogging devices or fog tubes. It is characterized by a wide range of droplet sizes, clearly illustrated by the flat curve. In particular, a high proportion of very large droplets settle in the immediate vicinity of the device, significantly reducing or impairing the efficiency of the application. Fewer droplets, and therefore less active ingredient, reach the target area.

[0026] Completely different conditions prevail when using the described fog tube 10. As the solid line shows, the majority of the droplets have a diameter in the range of approximately 10 µm to 30 µm. The proportion of larger droplets is small. This optimal droplet distribution is achieved using water as the carrier medium. This droplet spectrum is only slightly broader than the droplet spectrum that occurs when fog substances are discharged using oils as the carrier medium and operated with conventional fog tubes.

[0027] Due to the described design of the fog tube 10, the flow rate of the exhaust gas-fog substance-cooling air mixture with water as a carrier substance can be greatly increased with an optimal droplet spectrum.

[0028] The numerical values ​​described below are to be considered examples and do not limit the invention to them.

[0029] The overhang of pipes 3 to 6 beyond the respective inner pipe is in Fig. Let L1 to L4 be the dimensions of pipe 1. Pipe 3 projects beyond resonator pipe 2 with length L1. Similarly, pipe 4 projects beyond pipe 3 with length L3, and pipe 5 projects beyond pipe 4 with length L4. The following relationship applies: L1>L2>L3>L4

[0030] The ratio L1 : L2 lies in a range between approximately 1:0.6 and approximately 1:0.7. The length ratio L2 : L3 lies between approximately 1:0.4 and approximately 1:0.5, while the length ratio L3 : L4 lies between approximately 1:0.7 and approximately 1:0.8.

[0031] In one embodiment, the lengths are: L1=63 mm L2=42 mmL3=20 mmL4=15 mm

[0032] The cross-sectional areas of the ring channels 30 to 33 are in Fig.1 is designated A0 to A3. The annular channel 30 has the smallest cross-sectional area A0, while the adjacent annular channel 31 has the largest cross-sectional area A1. As a result, the primary cooling air flowing towards 26 in the annular space 25 has a higher flow velocity in the annular channel 30 than in the annular channel 31. The exhaust gas-mist mixture exiting the resonator 2 at high velocity is mixed with the cooling air also flowing at high velocity through the annular channel 30.

[0033] The annular channel 32 has a cross-sectional area A2, which is smaller than the cross-sectional area A1 of the annular channel 31, but larger than the cross-sectional area A3 of the annular channel 33. The annular channels 32 and 33 are designed to collect larger droplets that have formed in the pipes 4 and 5 and to return them to the exhaust gas-mist-cooling air mixture flowing through the fog pipe 10. For this purpose, the pipes 4 and 5 are each provided with at least one opening 23, 24, which leads into the respective annular channel 32, 33.

[0034] During operation of the fog machine, it is unavoidable that larger droplets 35 form at the outlet of pipes 4 and 5, which are no longer carried along by the exhaust gas-fog-cooling air mixture. These droplets 35 fall into the next pipe. The mixture flowing at high speed through pipes 4 and 5 creates a negative pressure in the annular channels 32 and 33 via the openings 23 and 24. This negative pressure draws the droplets 35 into the respective annular channels 32 and 33, from where they pass back into the exhaust gas-fog-cooling air stream via the openings 23 and 24. The droplets 35 are then carried along by the air stream and broken down.

[0035] The negative pressure in the annular channels 32, 33 is high because the pipes 5, 6 with their end sections 19, 20 are in close proximity to the pipes 4, 5. As a result, no outside air enters the annular channels 32, 33, which would impair the negative pressure.

[0036] In the exemplary embodiment, the cross-sectional area is A0 approximately 20 mm 2 A1 approximately 30 mm 2 A2 approximately 27 mm 2 A3 approximately 22 mm 2

[0037] The cross-sectional areas are coordinated in such a way that, on the one hand, the exhaust gas-fog-cooling air mixture exits the fog tube 10 at high speed, and on the other hand, the formation of larger droplets, which are not airborne aerosols, is kept to a minimum.

[0038] The following cross-sectional area ratios are optimal: A0:A1 = approximately 1:1.3 to approximately 1:1.6 A1:A2 = approximately 1:0.7 to approximately 1:0.9 A2:A3 = approximately 1:0.7 to approximately 1:0.8

[0039] Since the flow velocity v1 at the outlet of resonator tube 2 is very high, the overhang L2 of tube 3 can be correspondingly large. Accordingly, the difference between the volumes of tubes 3 to 6 can also be correspondingly large.

[0040] In the exemplary embodiment, pipes 3 to 6 have the following volumes: Pipe 3 V0≈680 mm³ Pipe 4 V1≈3000 mm³ Pipe 5 V2≈1500 mm³ Pipe 6 V3≈950 mm³

[0041] The volumes refer to the area of ​​pipes 3 to 6 that protrudes beyond the respective pipe.

[0042] Pipe 4 has the largest volume V1. Starting from this pipe 4, the volumes V2, V3 of pipes 5, 6 decrease. In conjunction with the decreasing supernatant L3, L4 and / or the decreasing flow velocity v3, v4, the discharge of the fogging agent is optimized with minimal droplet formation.

[0043] In the exemplary embodiment, a chamfer 36 is provided at the free end of the tube 3, forming a circumferential annular edge 37. It is advantageous to provide such a chamfer on the other tubes 4 to 6 as well. The annular edges form clean separation edges for optimal droplet formation.

Claims

[1] Device for discharging smoke substances, with a oscillating flame burner to which a resonator (2) is connected, into which a supply line (9) for the smoke substance opens and which projects into a first tube (3) of a smoke tube (10), wherein the smoke tube (10) has at least three further tubes (4, 5, 6) which, forming annular channels (32, 33), project axially beyond the respective inner tube, characterized by , that the third tube (5) is provided with at least one intake opening (24) located in its wall for larger fog droplets (35) located in the radially outer annular channel (33). [2] Device according to claim 1, characterized by that the second pipe (4) has at least one intake opening (23) for larger fog droplets (35) located in the annular channel (32). [3] Device according to one of claims 1 or 2, characterized by, that an annular channel (30) is formed between the first tube (3) and the resonator (2), which is in flow communication with an annular space (25) through which cooling air flows, the width (A0) of which is smaller than the width (A1) of the annular gap formed between the first tube (3) and the second tube (4). [4] Device according to claim 3, characterized by , that the annular channel (30) has a cross-sectional area (A0) that is smaller than the cross-sectional area (A1) of an annular channel (31) between the first pipe (3) and a second pipe (4) surrounding it at a distance. [5] Device according to any one of claims 1 to 4, characterized by , that the annular channel (32) between the second and the third tube (4, 5) has a cross-sectional area (A2) that is larger than the cross-sectional area (A0) of the annular channel (30) between the resonator (2) and the first tube (3) and / or the cross-sectional area (A1) of the annular channel (31) between the first and the second tube (3, 4). [6] Device according to any one of claims 1 to 5, characterized by , that the cross-sectional area (A3) of the annular channel (33) between the third and the fourth tube (5, 6) is larger than the cross-sectional area (A0) of the annular channel (30) between the resonator (2) and the first tube (3) and / or the cross-sectional area (A1) of the annular channel (31) between the first and the second tube (3, 4) and / or the cross-sectional area (A2) of the annular channel (32) between the second and the third tube (4, 5). [7] Device according to any one of claims 1 to 6, characterized by , that the ratios between the cross-sectional areas (A0, A1, A2, A3) of successive ring channels (30, 31, 32, 33) decrease. [8] Device according to claim 7, characterized by , that the cross-sectional area ratio between the radially innermost ring channel (30) and the radially adjacent ring channel (31) is between 1:1.3 and 1:1.

6. [9] Device according to any one of claims 1 to 8, characterized by, that the cross-sectional area ratio between the two radially central ring channels (31, 32) is between 1:0.7 and 1:0.

9. [10] Device according to any one of claims 1 to 9, characterized by , that the cross-sectional area ratio between the two radially outer ring channels (32, 33) is between 1:0.6 and 1:0.

9. [11] Device according to any one of claims 1 to 10, characterized by , that the superimposition (L1, L2, L3, L4) of the pipes (3, 4, 5, 6) decreases over the respective radially inner pipe in the flow direction (26) of the medium. [12] Device according to claim 11, characterized by , that the length ratio between the innermost tube (3) and the second tube (4) is between 1:0.6 and 1:0.

7. [13] Device according to claim 11 or 12, characterized by , that the length ratio between the two middle tubes (4, 5) is between 1:0.4 and 1:0.

5. [14] Device according to any one of claims 11 to 13, characterized by, that the length ratio between the two radially outer tubes (5, 6) is between 1:0.7 and 1:0.

8. [15] Device according to any one of claims 1 to 14, characterized by , that the inner tube (3) has a volume (V1) that is larger than the volume (V2) of the adjacent tube (5). [16] Device according to any one of claims 1 to 15, characterized by , that the volume (V3) of the outer tube (6) is smaller than the volume (V2) of the adjacent tube (5). [17] Device according to any one of claims 1 to 16, characterized by , that at least the radially outer ring channel (33), preferably the two radially outermost ring channels (32, 33), is / are sealed airtight at its or their end (19, 20) lying against the direction of flow (26), characterized by , that at least the inner tube (3) is provided on its inner end with a chamfer (36) to form an annular edge (37). [18] Fog tube for a device according to one of claims 1 to 17, wherein the fog tube (10) has at least four tubes (3, 4, 5, 6) which have an increasingly larger radius towards the free end and which, forming annular channels (31 to 33), project axially beyond the respective inner tube, characterized by , that the third tube (5) is provided with at least one intake opening (24) in its wall for larger fog droplets (35) located in the radially outer annular channel (33), which opens into the annular channel (33).

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