Mixing nozzle, device with mixing nozzle for dispensing multi-component masses and use of the device

Abstract

Mixing nozzle (1) with inlet openings (14, 14') and passage openings (12, 12') that can be connected to the outlet openings (21, 21') of a dispensing device, to a mixing chamber (3), wherein each passage opening (12, 12') is assigned to an inlet opening (14, 14') and a common storage chamber (10) is provided between the inlet openings (12, 12') and passage openings (14, 14'), wherein the passage openings (12, 12') are arranged on the wall of the storage chamber opposite the inlet openings offset from the inlet openings (14, 14') in such a way that they are not arranged overlapping in a parallel projection in order to prevent the components from shooting through, and wherein the passage openings (12, 12') are designed in such a way that the mixture passing through the respectively assigned inlet opening (14, 14') supplied components (25, 25') only enter the mixing chamber (3) through the passage openings (12, 12') when the common storage chamber (10) is filled.

Description

[0001] The invention relates to a device for dispensing multi-component materials, particularly for dental purposes, and a suitable mixing nozzle. The invention also relates to the use of the device.

[0002] Devices for multi-component masses, in which the individual, usually pasty, components are fed separately to a mixer, mixed by the mixer to form the desired multi-component mass, and then dispensed, are known from the prior art. The mixing ratio can be adjusted by feeding the components to be mixed in a corresponding volume ratio.

[0003] A corresponding device based on this basic principle is known from EP 1 029 585 B1. There, the individual components to be mixed are pressed out by a dedicated dispensing device in a predetermined, constant volume ratio through separate outlet openings of cartridges and, via inlet openings connected to the outlet openings, enter a common mixing chamber of a mixing nozzle. In or adjacent to the mixing chamber, fixed mixing baffles (static mixer) or rotating mixing blades (dynamic mixer) are arranged for mixing the separately supplied components into the desired multi-component mass with the desired volume ratios.

[0004] The device of EP 1 029 585 B1 further addresses the problem of component overflow. "Overflow" means that when the components begin to be extruded, a first component reaches the mixing chamber earlier than a second component, for example due to different flow behavior or different initial contact pressure. The overflowing portion of the first component passes through the mixing chamber without being sufficiently mixed with the other component(s). Only the first component then initially exits the mixing nozzle before the actual multi-component mass exits. The overflowing portion of the first component can cause problems during further processing of the extruded mass.

[0005] In EP 1 029 585 B1, the pre-flow of a component known to be prone to pre-flow is counteracted by providing a storage volume in the mixing nozzle in the flow path of this component from the inlet opening to the mixing chamber of the mixer. This storage volume initially fills completely with the component during extrusion before the component continues into the mixing chamber. The storage volume is to be adjusted to the expected pre-flow volume so that the components to be mixed enter the mixing chamber essentially simultaneously.

[0006] Documents DE 10 2005 054 153 A1 and DE 20 319 813 U1 show dispensing devices for multi-component masses, e.g. construction and insulating materials, in which two components to be mixed are fed separately from one another laterally into a common anteroom of a dynamic mixer, which is delimited by a perforated disc at the transition to the actual mixing area.

[0007] Document DE 10 2017 117 199 A1 discloses a mixer, in particular for dental materials, in which the pre-flow of one of the components to be mixed is addressed by all components first flowing into a common compensation channel and, only when this channel is completely filled, exiting through a common opening to the mixing chamber.

[0008] Document DE 10 2007 041 737 A1 provides a mixing device for viscous components, in which the components are fed into the mixing chamber through a plurality of feed channels distributed around the circumference and arranged alternately.

[0009] US 2017 / 0 265 969 A1 describes a reusable device for dispensing dental material, which allows for a comparable storage volume. In DE 101 12 904 A1, the storage volume is optimized with regard to friction losses.

[0010] A disadvantage of this prior art is that the flow volume of the component in question must be precisely known in order to determine the storage volume. Changes in the flow volume, e.g., due to different operating conditions during use of the device, such as component temperature, cannot be taken into account, so that the possibility of a component flowing ahead cannot be completely ruled out. Furthermore, the mixing nozzle according to EP 1 029 585 B1 is practically limited to a specific component mixture, as it is fundamentally not designed for other components with different flow volumes.

[0011] The invention is based on the object of creating a device for dispensing multi-component masses and a mixing nozzle suitable therefor, in which or when used, the disadvantages of the prior art no longer occur or only occur to a reduced extent.

[0012] This object is achieved by a mixing nozzle according to claim 1, a device according to claim 7 and a use of the device according to claim 8. Advantageous further developments are the subject of the dependent claims.

[0013] In the device according to the invention, the components discharged in the specified ratio from the outlet openings first pass through the inlet openings into a common storage chamber. This chamber is completely filled before the further introduced components enter the actual mixing chamber through the passage opening. The passage openings are designed and / or arranged such that, after the storage chamber is completely filled, only the component that is introduced into the storage chamber through the respective assigned inlet opening passes through a passage opening.

[0014] By first filling the storage chamber together before entering the mixing chamber through the passage(s) assigned to their respective inlet openings, the pre-flow of individual components can generally be completely compensated for. The ratio of the individual components is practically irrelevant for filling the storage chamber; once the chamber is completely filled, the individual components enter the mixing chamber through the passages in the same ratio as they were introduced through the inlet openings and can thus be mixed in the specified ratio to form the desired multi-component mass.In contrast to the prior art, in the device according to the invention, no fixed storage volume is specified for each leading component, but rather the individual leading and trailing components take up the volume they require in the storage chamber until it is completely filled.

[0015] In the event that a leading component already fills the storage chamber to such an extent that the leading component would also enter the flow path between the inlet opening of another component and one of its associated passage openings before the other component fills this area, a small initial deviation in the component ratios in the mixing chamber could occur until the other component has completely displaced the leading component from its flow path. This scenario can be completely avoided by ensuring the storage chamber is sufficiently large.

[0016] It is preferable if the cross-section of the storage chamber is several times larger than the passage openings to the mixing chamber. This ensures that the introduced components initially completely fill the storage chamber due to the lower flow resistance before passing through the passage openings, which represent a greater flow resistance.

[0017] The storage chamber and the mixing chamber can be separated from each other by a partition wall, whereby the passage openings can be arranged, for example, directly in the partition wall. The passage openings can each be provided in spatial proximity to the respective associated inlet opening and / or have a circular cross-section. The storage chamber is preferably annular and preferably arranged around the mixing chamber.

[0018] The passage openings are located on the wall of the storage chamber opposite the inlet openings. This reduces deflections when the components flow through the fully filled storage chamber. To prevent the components from overshooting, the passage openings are offset from the inlet openings in such a way that they do not intersect in a parallel projection—i.e., on a plane parallel to the wall.

[0019] It is preferred that the storage chamber has at least one vent opening. The vent openings preferably have such a small diameter that the components to be mixed do not pass through the vent openings at the expected pressures in the storage chamber. Appropriate vent openings can ensure that no unwanted air bubbles form in the storage chamber when the components are introduced.

[0020] The replaceable mixing nozzle can be designed as a static or dynamic mixing nozzle, ie it can have fixed mixing baffles or rotating mixing blades.

[0021] The individual components of the multi-component compound are preferably pasty compounds, such as those commonly used for dental purposes. "Pasty" in this context means that the compounds are not inherently flowable, but can only be forced through pipes, etc., using appropriate (extrusion) pressure.

[0022] For an explanation of the mixing nozzle according to the invention and the use according to the invention, reference is made to the above statements.

[0023] The invention will now be described by way of example using advantageous embodiments with reference to the accompanying drawings. They show: Fig. 1: schematic representations of a first embodiment of a mixing nozzle; Fig. 2a-c: schematic representations of the use of a first embodiment of a device with a mixing nozzle according to Fig. 1; and Fig. 3: schematic representations of an embodiment of a mixing nozzle according to the invention.

[0024] In Fig. Figure 1 shows a first embodiment of a mixing nozzle 1. The mixing nozzle 1 comprises a substantially cylindrical mixing chamber 3 defined by a mixing tube 2, in which static mixing baffles 4 are arranged.

[0025] At the end of the mixing tube 2 remote from the outlet opening 5 of the mixing tube 2, a storage chamber 10 is provided, arranged in a ring around the mixing tube 2 and separated from the mixing chamber 3 only by a partition 11. Two passage openings 12, 12' with a circular cross-section are provided in the partition 11. In addition, a plurality of vent openings 13 are provided in the partition 11 between the storage chamber 10 and the mixing chamber 3, the respective diameters of which are selected to be so small that only gases, such as air, can pass through, but not pasty masses.

[0026] Furthermore, two inlet openings 14, 14' are provided on the storage chamber 10, through which pasty masses can be introduced into the storage chamber. In each case, a passage opening 12, 12' is provided in spatial proximity to an inlet opening 14, 14', whereby the passage opening 12, 12' is each assigned to an inlet opening 14, 14'. In particular, from the detailed illustrations A, B in Fig. 1, the cross section of the storage chamber 10 is several times larger than the cross section of the passage opening 12, 12' in the partition wall 11 to the mixing chamber 3. This ensures that pasty components introduced through the inlet openings 14, 14' first completely fill the storage chamber 10 before the components in question enter the mixing chamber 3 through the passage openings 12, 12'. This will be explained below with reference to the Fig. 2 ac explained in more detail.

[0027] In Fig. 2a shows a device 20 for dispensing multi-component masses, which has a mixing nozzle 1 according to Fig. 1. The information already provided in connection with Fig. The mixing nozzle 1 described in Figure 1 and its inlet openings 14, 14' are connected to outlet openings 21, 21' of a dispensing device 22 shown only schematically. More precisely, the dispensing device 22 comprises only the double cartridge 23, in whose two chambers 24, 24' each of the components 25, 25' to be mixed is arranged and can be dispensed through the respective associated outlet opening 21, 21' by appropriately moving the pistons 26, 26'. For the synchronous movement of the pistons 26, 26', a widely known dispensing device from the prior art can be used; this device has been omitted for reasons of clarity and otherwise requires no further explanation.

[0028] The two chambers 24, 24' of the double cartridge 23 have the same diameter. Consequently, when the pistons 26, 26' are moved synchronously, an identical amount of the component 25, 25' contained therein is dispensed from each of the two chambers 24, 24', so that a multi-component mass with equal proportions of the two components 25, 25' is ultimately produced.

[0029] If the component 25' tends to run ahead, ie when an extrusion force is initially applied to the pistons 26, 26', the component 25' exits the outlet opening 21' earlier than the component 25 exits the outlet opening 21. This circumstance is in Fig. 2b. Due to the significantly larger cross-section of the storage chamber 10 compared to the cross-section of the passage opening 12', the leading component 25' initially collects exclusively in the storage chamber 10 and, in particular, does not enter the mixing chamber 3.

[0030] The second trailing component 25 also initially collects exclusively in the storage chamber 10 after passing through the inlet opening 14, until the storage chamber 10 is completely filled by the two components 25, 25', which are not mixed in the storage chamber 10. This is Fig. 2c. Due to the leading component 25', it occupies a larger volume in the completely filled storage chamber 10 than the trailing component 25. However, the path between the inlet openings 14, 14' and the respectively associated passage opening 12, 12' in the partition wall 11 is filled exclusively by the component 25, 25' introduced through the respective inlet opening 14, 14'. If the components 25, 25' are now further uniformly pressed out of the double cartridge 23, the components 25, 25' enter the mixing chamber 3 simultaneously and in the desired equal volume ratio and are mixed there in a known manner by the static mixing baffles 4 before the multi-component mass thus produced exits the outlet opening 5 of the mixing tube 2.

[0031] In Fig. 3 shows an embodiment of a mixing nozzle 1 according to the invention. The mixing nozzle 1 corresponds in many respects to that of Fig. 1, so that only the differences between the two versions will be discussed below. For the rest, please refer to the explanations for Fig. 1.

[0032] For the mixing nozzle 1 according to Fig. 3, the passage openings 12, 12' in the storage chamber 10 are no longer arranged perpendicular to the respective inlet openings 14, 14' but parallel thereto on the opposite wall of the storage chamber 10. This allows the number of 90° deflections of the material flows of the component 25, 25' entering via the inlet opening 14, 14' to be reduced: While in the embodiment according to Fig. 1 a first 90° deflection takes place between the inlet openings 14, 14' and the respective passage openings 12, 12' and a second 90° deflection takes place between passage openings 12, 12' and the static mixing baffles 4, which each have no influence on the mixing of the two components 25, 25', in the exemplary embodiment only one such 90° deflection is required, namely in the flow direction behind the passage openings 12, 12'. As can be seen from the Fig. As can be seen from the flow paths shown in Figure 3 for the two components 25, 25' when the storage chamber 10 is completely filled, only a slight deflection is necessary between the inlet openings 14, 14' and the respective passage openings 12, 12'.

[0033] To prevent one of the two components 25, 25' from passing through the storage chamber 10, the passage openings 12, 12' are arranged offset from the inlet openings 14, 14' such that they do not overlap in a parallel projection. In the illustrated embodiment, the passage openings 12, 12' are each arranged at the outer edge of the storage chamber 10 relative to the axis of the mixing tube 2.

Claims

[1] Mixing nozzle (1) with inlet openings (14, 14') and passage openings (12, 12') that can be connected to the outlet openings (21, 21') of a dispensing device, to a mixing chamber (3), wherein each passage opening (12, 12') is assigned to an inlet opening (14, 14') and a common storage chamber (10) is provided between the inlet openings (12, 12') and passage openings (14, 14'), wherein the passage openings (12, 12') are arranged on the wall of the storage chamber opposite the inlet openings offset from the inlet openings (14, 14') in such a way that they are not arranged overlapping in a parallel projection in order to prevent the components from shooting through, and wherein the passage openings (12, 12') are designed in such a way that the mixture passing through the respectively assigned inlet opening (14, 14') supplied components (25, 25') only then enter the mixing chamber (3) through the passage openings (12, 12'),when the common storage chamber (10) is filled., [2] Mixing nozzle according to claim 1, characterized by that the cross-section of the storage chamber (11) relevant for the flow resistance for the introduced components is larger than the cross-section of the passage openings (12, 12') to the mixing chamber determining the flow resistance, so that the flow resistance into the storage chamber (11) for the introduced components is lower than the flow resistance through the passage openings (12, 12'). [3] Mixing nozzle according to one of the preceding claims, characterized by that the passage openings (12, 12') have a circular cross-section. [4] Mixing nozzle according to one of the preceding claims, characterized by that the storage chamber (10) is annular and is preferably arranged around the mixing chamber (3). [5] Mixing nozzle according to one of the preceding claims, characterized bythat the storage chamber (10) has at least one vent opening (13), wherein the vent openings (13) preferably have such a small diameter that the components (25, 25') to be mixed do not pass through the vent openings (13) at the pressures to be expected in the storage chamber (10). [6] Mixing nozzle according to one of the preceding claims, characterized by that the mixing nozzle (1) is a static or dynamic mixing nozzle. [7] Device (20) for dispensing multi-component masses comprising - a dispensing device for dispensing the individual components (25, 25') of the multi-component mass through separate outlet openings (21, 21') assigned to them in a predetermined ratio; and - a replaceable mixing nozzle (1) according to one of the preceding claims, which is arranged such that the separate outlet openings (21, 21') of the dispensing device are connected to the inlet openings (14, 14') of the mixing nozzle (1). [8] Use of a device according to claim 7, characterized by that the individual components (25, 25') of the multi-component mass to be applied are pasty masses, in particular pasty dental masses.

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