Dosing unit and system with dosing unit and disinfection process

Abstract

Dosing unit (12) for atomizing liquids, with a two-component nozzle (14) which has a first fluid channel (16) and a second fluid channel (18) which runs at least partially within the first fluid channel (16) and is fluidically separated therefrom, wherein both fluid channels (16, 18) run in such a way that a fluid flowing through the second fluid channel (18) is atomized by means of the fluid flowing through the first fluid channel (16), wherein the two-component nozzle (14) has an inner tube (20) and an outer tube (22) and the first fluid channel (16) is delimited by an outer wall (24) of the inner tube (20) and an inner wall (26) of the outer tube (22), which tapers towards an outlet opening (30), so that the first fluid channel (16) is an annular channel, and the second fluid channel (18) runs at least partially in the inner tube (20) and tapers towards its outlet opening (30), wherein the inner tube (20) is mounted in the outer tube (22) in a linearly displaceable manner, such that an effective flow cross-section of the first fluid channel (16) varies by a displacement of the inner tube (20), characterized in that the dosing unit (12) comprises a housing (32) in which the inner tube (20) and the outer tube (22) are mounted and in which fluid connections (34, 36) for supplying fluids to the first and second fluid channels (16, 18) are formed.

Description

[0001] The invention relates to a dosing unit for atomizing liquids with a dual-component nozzle and to a system comprising a dosing unit and two mass flow controllers. Furthermore, the invention relates to a disinfection method.

[0002] In a two-fluid nozzle, a high-velocity gas or vapor mass flow serves as the energy source for the atomization process. The gas and the liquid to be atomized meet at an outlet of the two-fluid nozzle.

[0003] Such dosing units are used, for example, in disinfection processes. The disinfectant, such as hydrogen peroxide, is atomized using an air stream. A two-component nozzle creates a cold aerosol cone from the two components.

[0004] The flow cross-section of the two fluid channels for hydrogen peroxide and air is typically designed and fixed for a specific application. This means that different dosing units are required for different applications.

[0005] DE 42 03 273 A1 describes a two-fluid nozzle with an inner nozzle and an annular space coaxially surrounding the inner nozzle, into whose lateral surface a gas inlet nozzle opens. The annular space has an outlet opening surrounding the outlet opening of the inner nozzle.

[0006] CN 2 02 052 655 U discloses an airflow atomizing device with a spray gun comprising at least four telescopically arranged nozzles, wherein the center nozzle is a material liquid nozzle and the other nozzles are gas nozzles. The front part of the inner cavity of each gas nozzle is an atomization zone.

[0007] It is therefore an object of the invention to provide a variably usable dosing unit with a two-component nozzle.

[0008] This object is achieved according to the invention by a dosing unit for atomizing liquids, comprising a two-component nozzle which has a first fluid channel and a second fluid channel which runs at least partially within the first fluid channel and is fluidically separate from it, wherein both fluid channels run in such a way that a fluid flowing through the second fluid channel is atomized by means of the fluid flowing through the first fluid channel. The two-component nozzle has an inner tube and an outer tube, and the first fluid channel is delimited by an outer wall of the inner tube and an inner wall of the outer tube, which wall tapers towards an outlet opening, such that the first fluid channel is an annular channel, and the second fluid channel runs at least partially within the inner tube and tapers towards its outlet opening.The inner tube is mounted in the outer tube for linear displacement, such that displacement of the inner tube varies the effective flow cross-section of the first fluid channel. The dosing unit comprises a housing in which the inner tube and the outer tube are mounted and in which fluid connections are formed for supplying fluids to the first and second fluid channels.

[0009] The dosing unit according to the invention has a compact design.

[0010] Due to the ability of the inner tube to be moved within the outer tube, the mixing ratio of two fluids, one of which flows through the first fluid channel and one through the second fluid channel, can be flexibly adjusted.

[0011] Furthermore, by displacing the inner tube, the flow behavior of the fluid flowing through the first fluid channel, which is in particular a gas, can be influenced in such a way that the dispersion cone of the atomized fluid, which is in particular a liquid, can be varied. This allows the dosing unit to be used flexibly for various applications. Using a dosing unit according to the invention therefore allows for cost savings, since different dosing units do not need to be provided for different applications; instead, only the inner tube needs to be displaced.

[0012] Set-up times can also be reduced considerably, as the adjustment option eliminates the need to replace the dosing unit for different applications.

[0013] Both the inner and outer tubes are rigid.

[0014] According to one embodiment, the outer wall of the inner tube tapers toward the outlet opening of the second fluid channel, and the tapered section of the inner tube is arranged in the tapered section of the outer tube. This means that, viewed in cross-section, both the outer diameter and the inner diameter of the annular channel become progressively smaller toward the outlet opening. Thus, by moving the inner tube, the flow cross-section of the annular channel is varied. This allows, in particular, the scattering cone to be efficiently varied. For example, the angle of the scattering cone can be set to a value between 10° and 40° by adjusting the annular channel.

[0015] The inner tube can be mounted for linear displacement using a spindle drive. A spindle drive is mechanically simple to implement and easy to operate.

[0016] For example, the inner tube is connected to a threaded rod onto which an axially fixed lock nut is screwed, so that a relative rotation between the lock nut and the threaded rod moves the threaded rod and thus also the inner tube axially.

[0017] According to one embodiment, the inner tube is positively connected to a carriage, which is displaceably mounted by a linear drive, so that the inner tube is displaceably mounted by the carriage. This embodiment has the advantage that a drive can be arranged laterally offset from the inner tube, allowing the drive arrangement to be adapted to different installation space requirements.

[0018] The slide can delimit the second fluid channel in sections, thereby achieving a compact design of the dosing unit. For this purpose, the slide is preferably tubular.

[0019] The inner tube is moved either manually or automatically. Manual movement is particularly cost-effective. Automatic movement, on the other hand, offers the advantage of being able to adjust the movement very precisely and is also particularly convenient. Furthermore, with automatic adjustment, the drive does not need to be accessible to a user, but can be controlled from a workstation, for example.

[0020] The inner tube is guided along the outer tube, particularly in sections. For example, the inner tube may have lateral projections or a collar that rests against the inner wall of the outer tube. This type of guide ensures that the inner tube is mounted particularly securely within the outer tube. The guide also centers the inner tube within the outer tube.

[0021] In the case of a circumferential collar, recesses are provided in the collar in order not to block fluid flow through the first fluid channel.

[0022] The first fluid channel and the second fluid channel open, for example, into a mixing chamber, with the mixing chamber being formed in the outer tube and adjoining the first fluid channel. Atomization takes place in the mixing chamber.

[0023] According to one embodiment, a guide element is arranged in the housing, in particular screwed into the housing, wherein the second fluid channel extends through the guide element and the slide is slidably mounted on the guide element. The positive connection of the slide to the inner tube and the mounting on the guide element ensure reliable sealing of the second fluid channel.

[0024] The second fluid channel, for example, runs in a straight line. This also contributes to a compact design. Furthermore, a straight fluid channel is particularly easy to manufacture.

[0025] Alternatively, the second fluid channel can have a bend or a curve. This allows a fluid connection to be arranged laterally offset from the inner tube.

[0026] The object is further achieved according to the invention by a system with a dosing unit according to the invention. The system has a first mass flow controller for regulating a fluid flow through the first fluid channel and a second mass flow controller for regulating a fluid flow through the second fluid channel. Such a system enables particularly precise adjustment of the mixing ratio of two fluids.

[0027] The invention further provides a disinfection method using the dosing unit or system according to the invention. According to the invention, "disinfection" also includes "sterilization."

[0028] Further advantages and features of the invention will become apparent from the following description and the accompanying drawings, to which reference is made. In the drawings: - Fig. 1 partially schematically shows a system according to the invention with a dosing unit according to the invention for carrying out the disinfection method according to the invention, - Fig. 2 a sectional view of a dosing unit according to the invention, - Fig. 3 the dosing unit Fig. 2 in a perspective view, - Fig. 4 a sectional view of another dosing unit according to the invention, - Fig. 5 the dosing unit Fig. 2 in a first state, - Fig. 6 the dosing unit Fig. 2 in a further state with enlarged spray cone, - Fig. 7 the dosing unit Fig. 2 in a further state with a further enlarged spray cone, - Fig. 8 the dosing unit Fig. 2 in a further state with an even larger spray cone - Fig. 9 the dosing unit Fig. 2 in a further state with maximum enlarged spray cone, and - Fig. 10 a diagram illustrating an aerosol quality and an air consumption of the dosing unit according to the invention in comparison to a conventional dosing unit.

[0029] Fig. 1 shows a system 10 with a dosing unit 12 which is suitable for atomizing liquids.

[0030] According to one application example, hydrogen peroxide is atomized using air for disinfection purposes.

[0031] The dosing unit 12 comprises a two-component nozzle 14 with a first fluid channel 16 which is annular in cross section and a second, central fluid channel 18, wherein the second fluid channel 18 runs in the axial course in sections within the first fluid channel 16 and is fluidically separated from it.

[0032] The two fluid channels 16, 18 extend in such a way that a fluid flowing through the second fluid channel 18, in particular hydrogen peroxide, is atomized by means of the fluid flowing through the first fluid channel 16, in particular air.

[0033] Specifically, the two-fluid nozzle 14 comprises an inner tube 20 and an outer tube 22, and the first fluid channel 16 is defined by an outer wall 24 of the inner tube 20 and an inner wall 26 of the outer tube 22. The first fluid channel 16 is thus an annular channel.

[0034] The inner wall 24 of the outer tube 22 tapers towards an outlet opening 28 downstream of the conically tapered end of the inner tube 20.

[0035] The second fluid channel 18 runs at least partially in the inner tube 20 and also tapers towards its outlet opening 30.

[0036] In addition, as mentioned, the outer wall 24 of the inner tube 20 also tapers towards the outlet opening 30 of the second fluid channel 18.

[0037] The tapered portion of the inner tube 20 is disposed in the tapered portion of the outer tube 22.

[0038] Consequently, the annular channel tapers conically towards the outlet opening 28.

[0039] The first fluid channel 16 and the second fluid channel 18 open into a mixing chamber 31, wherein the mixing chamber 31 is formed in the outer tube 22 and connects to the first fluid channel 18.

[0040] Starting from the mixing chamber 31, the outer tube 22 extends a short distance, so that an atomized fluid jet emerging from the outlet openings 28, 30 or from the mixing chamber 31 is partially shielded. This creates a chamber 33 with a larger cross-section than the mixing chamber 31, e.g., by at least a factor of 3.

[0041] The dosing unit 12 also comprises a housing 32 in which the inner tube 20 and the outer tube 22 are mounted and through which the fluid channels 16, 18 consequently run.

[0042] Fig. Figure 3 shows the dosing unit 12 in a perspective view, wherein the shape of the housing 32 is Fig. 3 is evident.

[0043] The housing 32 also contains fluid connections 34, 36 (see also Fig. 2) for supplying fluids to the first fluid channel 16 and to the second fluid channel 18.

[0044] In addition, Fig. 3 illustrates the attachment of the outer tube 22 to the housing 32.

[0045] The system 10 also includes a mass flow controller 38 (see Fig. 1) for regulating a fluid flow through the first fluid channel 16 and a second mass flow controller 40 for regulating a fluid flow through the second fluid channel 18.

[0046] In known dosing units, the inner tube 20 and the outer tube 22 are fixedly positioned relative to each other.

[0047] In the dosing unit 12 according to the invention, the inner tube 20 is mounted in the outer tube 22 in such a way that a displacement of the inner tube 20 varies an effective flow cross-section of the first fluid channel 16.

[0048] According to an embodiment described in Fig. 2, the inner tube 20 is mounted so as to be linearly displaceable by means of a spindle drive 42.

[0049] Here, the inner tube 20 is firmly connected to a threaded rod 44, onto which a lock nut 46 rigidly fastened to the housing 32 is screwed, so that a user can move the inner tube 20 linearly by rotating the threaded rod 44 at a frontal drive geometry of the threaded rod 44 (here, for example, a slot).

[0050] The spindle drive 42 is therefore arranged coaxially to the inner tube 20.

[0051] Instead of a manual drive, the drive can also be implemented as an electric motor to enable automatic displacement of the inner tube 20. For the sake of simplicity, such an electric motor-driven rotational or axial drive is not shown in the figures.

[0052] To ensure stable guidance of the inner tube 20, the inner tube 20 is guided in sections along the outer tube 22 in the exemplary embodiment. For this purpose, the inner tube 20 has at least one radially projecting projection 48, e.g., an annular collar. Instead of projections 48, the inner tube 20 can have a collar with recesses.

[0053] In the Fig. 2, the second fluid channel 18 runs from the fluid connection 36 through the housing 32 to the threaded rod 44 and then through the threaded rod 44, which has an opening 50 and an adjoining channel running within the threaded rod 44, to the inner tube 20.

[0054] In this case, the fluid channel 18 has a kink.

[0055] Fig. Fig. 4 shows a further embodiment of a dosing unit 12 in a sectional view, which can be used equally in the system 10 according to Fig. 1 can be used.

[0056] For identical structures with identical functions known from the above embodiment, the same reference numerals are used below and reference is made to the previous explanations, with the differences of the embodiment being discussed below in order to avoid repetition.

[0057] The embodiment according to Fig. 4 differs from the embodiment according to Fig. 2 by the way in which the inner tube 20 is driven.

[0058] Due to the different design of the drive, it is possible to design the second fluid channel 18 in a straight line, as will be described in more detail below.

[0059] In the embodiment according to Fig. 4, the drive is not arranged coaxially to the inner tube 20, but a linear drive 52 is arranged axially offset to it.

[0060] The linear drive 52 comprises a rotatably mounted threaded rod 54 that is axially fixed. In the exemplary embodiment, the threaded rod 54 is axially fixed in the housing 32 by pins 56.

[0061] In order to rotate the threaded rod 54, an engagement geometry 58 is provided at a freely accessible end.

[0062] A driver 60 is in toothed engagement with the threaded rod 54 and is moved linearly when the threaded rod 54 rotates.

[0063] A carriage 62 is attached to the driver 60. In particular, the driver 60 is screwed to the carriage 62.

[0064] The slide 62 is positively connected to the inner tube 20.

[0065] This means that when the threaded rod 54 rotates, the carriage 62 is moved linearly via the driver 60 and takes the inner tube 20 with it.

[0066] The slide 62 also forms a section boundary of the second fluid channel 18. For this purpose, the slide 62 is tubular.

[0067] To guide the slide 62, a guide element 64 is arranged in the housing, on which the cylindrical slide 62 is slidably mounted by pushing the slide 62 onto the guide element 62.

[0068] In the exemplary embodiment, the guide element 64 is designed as a sleeve which is screwed into the housing 32.

[0069] The second fluid channel 18 runs through the guide element 64, whereby the straight course of the second fluid channel 18 is possible.

[0070] To seal the second fluid channel 18, seals 66 are provided on the guide element 64, in particular between the guide element 64 and the carriage 62.

[0071] Furthermore, a seal 68 is provided between the inner tube 20 and the housing 32 to seal the first fluid channel 16 relative to the second fluid channel 18.

[0072] As already mentioned in connection with Fig. 2, the linear drive 52 can also be driven by an electric motor instead of manually.

[0073] Based on the Fig. 5 to 9, a function of the dosing unit 12 is illustrated, in particular with reference to the Fig. 2 illustrated embodiment of the dosing unit 12. The functioning of the Fig. However, the embodiment illustrated in Figure 4 is identical apart from the different drive.

[0074] In the Fig. 5 to 9, the dosing unit 12 is shown in different states, wherein the inner tube 20 is in a different position relative to the outer tube 22.

[0075] Based on the Fig. 5 to 9 it can be seen that an effective flow cross-section of the first fluid channel 16 can be varied by displacing the inner tube 20.

[0076] In particular, the scattering cone of the two-component nozzle 14 can be varied by changing the annular channel. For example, the angle of the scattering cone can be set to a value between 10° and 40°.

[0077] Specifically, by turning back the inner tube 20, i.e. by enlarging the annular channel, the air flow in the first fluid channel 16 can be increased, whereby the scattering cone becomes more pointed (see in particular Fig. 5).

[0078] By pre-turning the inner tube 20, i.e. by reducing the size of the annular channel, the air flow becomes smaller and thus the scattering cone becomes wider.

[0079] In addition, the droplet size and number of the aerosol can be influenced by adjusting the ring channel.

[0080] In the diagram in Fig. 10, on the one hand, the bar diagrams illustrate an aerosol quality of a conventional dosing unit with a static ring channel in comparison with an aerosol quality of a dosing unit 12 according to the invention with a variable ring channel for different sterilization volumes.

[0081] The aerosol quality is shown in % on the left vertical axis, while the sterilization volume in cm 3 is applied.

[0082] Aerosol quality refers to the degree of optimal droplet size achieved during atomization.

[0083] Optimization for different disinfection or sterilization volumes is required, for example, when an application needs to be able to adapt flexibly and without major conversion work to different liquid and air volumes while maintaining consistent aerosol quality. One possible application is the sterilization of containers of different sizes or shapes in the packaging industry.

[0084] The diagonally hatched columns represent the aerosol quality of a conventional dosing unit and the vertically dashed columns represent the aerosol quality of a dosing unit 12 according to the invention.

[0085] The bar chart shows that when using a conventional dosing unit with a fixed first fluid channel 16, the aerosol quality fluctuates greatly, whereas with the dosing unit 12 according to the invention, a constant aerosol quality can be achieved.

[0086] The line diagrams illustrate the air consumption at different sterilization volumes both for a system with a conventional dosing unit and for a system 10 with a dosing unit 12 according to the invention.

[0087] The air consumption in nanoliters per minute is plotted on the right vertical axis.

[0088] The dashed line illustrates the air consumption of a system with a conventional dosing unit and variable fluid supply. The dotted line illustrates the air consumption of a system 10 according to the invention with a dosing unit 12 according to the invention.

[0089] By additionally regulating air consumption by adjusting the flow cross-section of the first fluid channel 16, combined with regulating the liquid supply, optimal aerosol quality can always be generated for different sterilization volumes. In contrast to a conventional system, the system 10 according to the invention allows air consumption to be continuously increased even with high sterilization volumes.

Claims

[1] Dosing unit (12) for atomising liquids, comprising a two-component nozzle (14) which has a first fluid channel (16) and a second fluid channel (18) which extends at least partially within the first fluid channel (16) and is fluidically separated therefrom, wherein both fluid channels (16, 18) extend in such a way that a fluid flowing through the second fluid channel (18) is atomised by means of the fluid flowing through the first fluid channel (16), wherein the two-component nozzle (14) has an inner tube (20) and an outer tube (22) and the first fluid channel (16) is delimited by an outer wall (24) of the inner tube (20) and an inner wall (26) of the outer tube (22), which tapers towards an outlet opening (30), so that the first fluid channel (16) is an annular channel, and the second fluid channel (18) runs at least partially in the inner tube (20) and tapers towards its outlet opening (30), wherein the inner tube (20) is mounted in the outer tube (22) in a linearly displaceable manner, such that an effective flow cross-section of the first fluid channel (16) varies by a displacement of the inner tube (20), characterized by that the dosing unit (12) comprises a housing (32) in which the inner tube (20) and the outer tube (22) are mounted and in which fluid connections (34, 36) for supplying fluids to the first and second fluid channels (16, 18) are formed. [2] Dosing unit (12) according to claim 1, characterized by that the outer wall (24) of the inner tube (20) tapers towards the outlet opening (30) of the second fluid channel (18) and the tapered section of the inner tube (20) is arranged in the tapered section of the outer tube (22). [3] Dosing unit (12) according to one of the preceding claims, characterized by that the inner tube (20) is mounted so as to be linearly displaceable by means of a spindle drive (42). [4] Dosing unit (12) according to one of the preceding claims, characterized by that the inner tube (20) is positively connected to a carriage (62) which is displaceably mounted by means of a linear drive (52), so that the inner tube (20) is displaceably mounted by means of the carriage (62). [5] Dosing unit (12) according to claim 4, characterized by that the carriage (62) delimits the second fluid channel (18) in sections. [6] Dosing unit (12) according to one of the preceding claims, characterized by that the displacement of the inner tube (20) is carried out manually or automatically. [7] Dosing unit (12) according to one of the preceding claims, characterized by that the inner tube (20) is guided in sections on the outer tube (22). [8] Dosing unit (12) according to one of the preceding claims, characterized bythat the first fluid channel (16) and the second fluid channel (18) open into a mixing chamber (31), wherein the mixing chamber (31) is formed in the outer tube (22) and adjoins the first fluid channel (16). [9] Dosing unit (12) according to claim 4 or 5, characterized by that a guide element (64) is arranged in the housing (32), wherein the second fluid channel (18) extends through the guide element (64) and the carriage (62) is slidably mounted on the guide element (64). [10] Dosing unit (12) according to one of the preceding claims, characterized by that the second fluid channel (18) runs in a straight line. [11] System (10) with a dosing unit (12) according to one of the preceding claims, comprising a first mass flow controller (38) for regulating a fluid flow through the first fluid channel (16) and a second mass flow controller (40) for regulating a fluid flow (18) through the second fluid channel (18). [12] Method for disinfecting objects with a dosing unit according to one of claims 1 to 10 or a system according to claim 11, wherein a disinfectant is introduced into the second fluid channel and air is introduced into the first fluid channel (16), wherein the disinfectant with which an object is disinfected is atomized at the outlet opening (30).

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