Automatic mixing chamber changing device

Abstract

Mixing device (10) for mixing two or more substances, comprising: - a body portion (12) in which respective feed channels (14, 16) for the first and second substances are provided; - a drive shaft (18) which extends along a longitudinal axis (L18) through the body portion (12) and is drivable for rotation about the longitudinal axis (L18); - a mixing tip (100) comprising an outer shell (104) and a mixer (102) received therein; and - a connecting unit (20) associated with the body section (12), which is configured to detachably connect the mixing tip (100) to the body section (12) by means of a counter-unit (108) associated with the mixing tip (100), wherein the mixer (102) is coupled to the drive shaft (18) in the connected state of the mixing tip (100) and can be driven in rotation by the latter; characterized in that the mixing device (10) further comprises an automatic changing device (200) configured to automatically connect a mixing tip (100) to the body section (12) in a state in which initially no mixing tip (100) is connected to the body section (12).

Description

The present invention relates to a mixing device for mixing two or more substances, comprising a body section in which respective feed channels for the first and the second substance are provided, a drive shaft which extends along a longitudinal axis through the body section and is drivable for rotation about the longitudinal axis, a mixing tip comprising an outer shell and a mixer accommodated therein, and a connecting unit assigned to the body section, which connecting unit is configured to connect the mixing tip to the body section in a detachable manner by means of a counter unit assigned to the mixing tip, wherein the mixer is coupled to the drive shaft in the connected state of the mixing tip and is drivable in rotation by the latter.Such mixing devices of the generic type, in which a drivable mixer is provided in order to be able to ensure the mixing of the two substances to be mixed in the desired manner, are also known as dynamic mixing devices and differ from purely passive mixing devices, in which two substances are combined only in a mixing chamber and then discharged as a mixture without mechanical swirling or the like of the two substances being carried out.It is known that in such mixing devices the mixing tips must be regularly exchanged, since they can become soiled, clogged or otherwise unusable over time, in particular in cases in which the substances to be mixed tend to harden or other reactions which promote premature wear of the mixing tips. In this context, in addition to the pure replacement of used mixing tips with new mixing tips, further manual interventions by operators are frequently necessary, for example an at least partial cleaning of the body portion at its transition to the mixing tip, which results in increased time and work effort.Furthermore, it should be pointed out that in known mixing devices of the generic type a corresponding installation of a new mixing tip or the exchange of a used mixing tip must also be carried out manually by an operator, which is likewise already disadvantageous with regard to the operating efficiency of the mixing device and accordingly offers potential for improvements.It is therefore the object of the present invention to eliminate the above-described disadvantages of the known prior art and to further develop a generic mixing device for mixing two or more substances in such a way that operation thereof as free from maintenance as possible is made possible over a long period of time without any necessary manual interventions by an operator.This object is achieved according to a first aspect of the present invention in that the mixing device according to the invention further comprises an automatic changeover device which is configured to connect a mixing tip to the body section in an automatic manner in a state in which no mixing tip is initially connected to the body section.Here, the term "automatic connection" is to be understood such that an operator intervention in a manual manner is not necessary. In particular, the corresponding connection process can be followed by a process of separating a previously used mixing tip or, for example, can also be carried out when the mixing device is put into operation starting from a state in which initially no mixing tip was previously attached to the body section. It should also be noted that the mixing tips usable in a corresponding mixing device according to the invention will generally also have, in addition to their outer shell and their mixer, a head portion which forms a structural component thereof and can, for example, support the shell in a suitable manner. Accordingly, such a head section can also be considered as part of the casing itself in a functional viewing mode, since it also surrounds the mixer accommodated in the mixing tip in sections. In the region of this head section, the connection to the body section of the mixing device is likewise usually to be produced.The provision of the automatic changing device according to the invention accordingly makes it possible to pick up a new mixing tip in an automatic manner either at regular intervals or, for example, also upon input by an external control, after manual triggering by an operator or when a need for changing the corresponding mixing tip has been detected by means of suitable sensors. It is understood that different types of mixing tips can also be used together with a single body section, which may differ, for example, with regard to the configuration of their mixers, as long as they are each matched to a use with the corresponding body section and the connection unit assigned to it.Although different configurations of changing devices are conceivable within the scope of the mixing device according to the invention, this can comprise, for example, a displacement unit, in particular a 3- or 6-axis robot, which is configured to displace the body section along at least one axis. In less expensive designs, however, only a displacement of the body section with respect to one or two axes could also be provided. However, in a kinematic reversal it would of course also be conceivable to displace the mixing tip to be accommodated by means of a correspondingly configured changing device in order to move it to the body section, which could remain stationary in such a configuration. In this case, too, robot arms could be used, wherein in both cases these could optionally be additionally equipped with suitable sensor units and / or operatively coupled, which could monitor the connection process between the body portion and the mixing tip and optionally readjust it, for example optical sensors with a downstream image recognition to ensure the correct relative alignment of the two components to be connected or the like.Furthermore, the mixing device according to the invention could further comprise a magazine which is configured to receive and contain at least one mixing tip in such a way that it can be connected to the body section by means of the changing device. Again, the magazine could be held in a fixed position during a process of connecting a mixing tip to the body portion, provided that the body portion is moved in relation thereto for the connection process, or the magazine itself could be supported in a movable manner by a corresponding automatic changing device, so that a respective mixing tip can be brought up to the body portion in this way.It is also understood that such a magazine could in principle hold and reserve as many mixing tips as desired, wherein the corresponding number could be matched to the effect that, for example, within the scope of extensive maintenance work which is usually carried out anyway, the corresponding magazine could then be manually replenished by a human operator, but between these maintenance intervals the corresponding mixing device has sufficiently many mixing heads available to enable continuous operation with only automatic changeover operations thereof.Furthermore, it is understood that the mixing device according to the invention can likewise be configured for automatically dispensing used or generally exchanged mixing tips, wherein, in connection with the above-mentioned use of a displacement unit, for example, the body section could first be moved into an area in which a used mixing tip could be deposited or dropped, before a new mixing tip can be taken over at another position, for example from the magazine just mentioned. For this purpose, the connecting unit can then at the given time release the connection to the counter unit and the mixing tip can separate from the body section either purely by gravity or with the aid of a detachment device, for example a gripper or the like.In this connection, it should be pointed out that the connecting unit of the mixing device according to the invention can comprise, for example, at least one electromagnet and the counter unit can comprise at least one ferromagnetic element, which enables a particularly simple, low-maintenance, reliable connection between the body section and the mixing tip, and yet which is easy to separate. Of course, in principle, other types of connecting units and counter units are also conceivable, which can act, for example, via a form fit such as a locking or engagement. For this purpose, suitable latching or engagement sections can then be provided as counter sections on the mixing tip, which allow a gripping or latching of corresponding connection units on the body section. On the other hand, in the case of using at least one electromagnet as a connecting unit, the corresponding counter unit at the mixing tip can be embodied as a simple steel disk or as a similar component, which enables a particularly simple and cost-effective production thereof. Theoretically, however, it would also be conceivable to assign the at least one electromagnet to the mixing tip, but this would require a much more complex construction with a corresponding controllable energy supply, which on the other hand can be effected much more easily in the region of the body section.Furthermore, the mixing device according to the invention can comprise a connecting unit displacement device which is configured to displace the connecting unit with respect to the body section, in particular in the direction of the longitudinal axis of the drive shaft. Such a displacement device for the connecting unit enables a particularly precise connection to corresponding mixing tips and can serve, for example, to compensate tolerances in the magazine mentioned above, on account of which the corresponding mixing tips are held slightly deviating from their intended position. In particular, the coupling of the mixer to the drive shaft, which is discussed further below, can always be carried out in a precise and controlled manner by the provision of such a displacement unit.In this connection, also to ensure the correct connection of the mixing tip to the body portion, the drive shaft and the mixer of the mixing tip may be provided with self-aligning end portions in the region of their coupling. In this way, it can be ensured that the intended rotating drive of the mixer by means of the drive shaft is carried out in the desired manner in the connected state, and the coupling operation of the two components per se can be simplified.In particular, for this purpose, the end section of the drive shaft can comprise at least one wedge-shaped section and the end section of the mixer can comprise at least one recess for receiving the wedge-shaped section and also outlet surfaces in order, when the mixer is pushed onto the end section of the drive shaft, to guide the at least one recess onto the at least one wedge-shaped section, where a positive fit for transmitting the rotational movement of the drive shaft to the mixer is accordingly ensured. Of course, this configuration would also be conceivable in the reverse manner, i.e. an assignment of the wedge-shaped section to the mixer and of the recess to the end section of the drive shaft, whereby the same advantages would only be achieved in kinematic reversal.Furthermore, the mixer may comprise an enlarged diameter portion which is received in a corresponding groove on the inner side of the outer shell. In this way, when dispensing or separating the corresponding mixing tip, it is ensured that the sleeve is not removed via the mixer and the latter thus remains connected to the drive shaft. Accordingly, the cooperation of the enlarged diameter portion and the groove on the shell ensures that the components of the mixing tip always remain as a single assembly and cannot be detached from each other.According to a second aspect of the present invention, which is to be claimed both alone and in combination with the first aspect and the developments of the invention discussed up to now, the feed channels and the mixing tip are configured such that the two substances come into contact with one another only in the region of the mixer, such that a mixing chamber for the two substances lies completely in the region of the mixing tip. In this way, it is prevented that mixing of the substances and thus contact of the corresponding resulting mixture with components of the mixing device other than the mixing tip occurs, which can significantly reduce the required cleaning effort in the event of a change of the mixing tip. In particular, this measure according to the invention cannot result in situations in which the corresponding, possibly solidifying, mixture sets on sections of the body section and the corresponding regions must accordingly be cleaned off before a new mixing tip is connected. Consequently, both alone and in particular in combination with the first aspect, this second aspect of the invention achieves efficient operation and reduced maintenance effort or a reduced number of necessary manual interventions during operation of the mixing device according to the invention.For example, the two feed channels can introduce their respective substance laterally, but at different heights with respect to a longitudinal axis of the mixing tip, wherein at least a first of the two substances is introduced below the upper end of the mixer with respect to the longitudinal direction of the mixing tip, wherein it is assumed that the mixing tip is arranged downward in a vertical extension of the longitudinal axis of the drive shaft. Accordingly, this measure prevents the two substances from coming into contact with one another already in a position which is above the mixer with respect to the longitudinal axis of the mixing tip.In order to facilitate the introduction of the aforementioned first substance into the mixing tip, the sleeve of the mixing tip can have a circumferential groove and a plurality of transverse holes in the region of the introduction of the first substance, through which the corresponding substance can then respectively enter the interior of the mixing tip and only come into contact with the second substance there. It is understood here that the sheath of the mixing tip discussed in this context can of course also relate to a head section of the mixing tip, provided such a head section is provided in the region of the connection of the mixing tip to the body section.With regard to the input of the second substance, in the region of the coupling of the mixer to the drive shaft, a chamber can furthermore be provided, into which the feed channel of the second substance opens laterally, so that this second substance will enter the mixing tip substantially along the longitudinal direction of the latter and will only come into contact with the first substance there. Alternatively, however, the second substance can also be introduced into the mixing tip in a similar manner as described above for the first substance through an annular channel or a circumferential groove and transverse bores, wherein the corresponding groove would then have to be provided spaced apart from the corresponding groove for the first substance with respect to the longitudinal direction of the mixing tip.Furthermore, the mixing device according to the invention can comprise a vibration sensor which is configured to check a correct state of the mixer by means of an evaluation of vibration patterns. In particular, this vibration sensor can be placed or can be placed on the sleeve of the mixing head from the outside and can carry out a comparison on the basis of known expected vibration patterns of functional mixing heads and trigger suitable countermeasures in the event of a deviation, for example a shutdown of the mixing device until a manual checking of the corresponding mixing tip by an operator or an exchange thereof for a functional mixing tip has taken place. By means of such vibration sensors, it is also possible, for example, to detect a fracture of a mixer within the casing or a similar defect, which can likewise ensure the desired mode of operation of the mixing device according to the invention and prevent erroneous operating states.Finally, it should be pointed out that the mixer usable in the mixing device according to the invention can be produced from a plastic, in particular by means of 3D printing or injection molding.Further features and advantages of the present invention will become more apparent from the following description of an embodiment thereof when taken in conjunction with the accompanying drawings. These show in detail: FIGS. 1a to 1c are three sectional views of a mixing device according to the invention during a process of connecting its body portion to a mixing tip; FIG. 2 is an enlarged view of the connecting portion of the body portion with the mixing tip in the connected state of the two; FIG. 3 is an alternative view of the portion of FIG. 2; FIG. 4 shows a detailed view of the connection region of the mixer of the mixing device from FIGS. 1 ato 1 cto the corresponding drive shaft; FIG. 5 is a detail view of a portion of the mixing tip; and FIG. 6 shows an external view of the mixing device from FIGS. 1 ato 1 c, with a vibration sensor mounted thereon.Referring first to Figures 1a to 1c, a mixing device according to the invention, generally designated by the reference numeral 10, is shown in three states during an operation of connecting its body portion 12 to a corresponding mixing tip 100 in respective cross-sectional views. In this case, the basic structure of the body section 12 is known from the prior art in that it comprises two feed channels 14 and 16 with corresponding sealing means, which are supplied by means of connection sections 14 aand 16 awith a corresponding first and second substance, which are to be mixed by the mixing device 10. Furthermore, a drive shaft 18 extends through the body section 12 along a longitudinal axis L 18 which is here located in the top-bottom direction and can be driven to rotate by means of a drive, not shown in any more detail here, and is mounted within the body section 12 by means of corresponding bearings.In the operational state of the mixing device 12 which is illustrated in FIG. 1 c, the mixer 102 of the mixing tip 100 is pushed onto the drive shaft 18 just mentioned, so that the latter can likewise be set in rotation within the casing 104 of the mixing tip and the device 10 is consequently a dynamic mixing device. Accordingly, the longitudinal axis L 102 of the mixer 102 is an extension of the longitudinal axis L 18 of the drive shaft 18.Furthermore, the mixing tip 100 comprises a head section 106, which can be understood as part of the casing 104 and in the region of which the connection between the mixing tip 100 and the body section 12 of the mixing device 10 is brought about. For this purpose, the body section 12 is assigned a connecting unit 20 which can be connected in a detachable manner to a counter unit 108 of the mixing tip 100, for example in that the connecting unit 20 comprises one or more electromagnets and the counter unit 108 is designed as a ferromagnetic disc which is accordingly attracted and held on the at least one electromagnet during operation. The dispensing of the mixture of the two substances from the mixing tip 100 takes place during operation of the device on the lower side thereof in FIGS. 1 ato 1 c, by means of a nozzle section 100 a.Furthermore, the mixing device 10 comprises an automatic changing device 200, which is only schematically illustrated here and by means of which the mixing tip 100 and the body portion 12 of the mixing device 10 can be connected in an automatic manner, for example in that the changing device 200 comprises a displacement unit such as a 3- or 6-axis robot arm, which makes it possible to bring the body portion 12 and the mixing tip 100 into a suitable alignment with respect to one another so that the ferromagnetic disc 108 is attracted by the action of the at least one electromagnet 20 and the two components are connected to one another. In this context, it should be pointed out that at such a point in time the mixing tip 100 can be located in a magazine 202, which is merely indicated schematically and in which further mixing tips 100 can also be held in a suitable manner in order to enable a corresponding picking up of in each case one of the mixing tips 100.The corresponding connection process will now be explained with reference to FIGS. 1a to 1c, wherein in this connection reference should be made in particular to the connection unit displacement device 22, which by means of suitable lifting cylinders enables displacement of the connection unit 20 with respect to the remaining components of the body section 12, including the drive shaft 18 and the feed channels 14 and 16.By means of this displacement device 22, the connecting unit 20 is first lowered to the maximum in the states from FIGS. 1 aand 1 b, or is displaced away from the drive shaft 18 along the longitudinal direction L 18. In this state, the body section 12 is now moved by means of the automatic changing device 200 to the mixing tip 100 present in the magazine 202 and the electromagnets of the connecting unit 20 are put into operation, so that in the state of FIG. 1 b, there is now already a connection between the connecting unit 20 and the counter unit 108. Subsequently, as can be seen in FIG. 1 c, the connecting unit 20 is displaced by means of the connecting unit displacement device 22 in the direction of the longitudinal axis L 18 of the drive shaft 18 upwards towards the latter until the mixer 102 of the mixing tip 100 and the drive shaft 18 couple to one another. This coupling process will be described in more detail further below in connection with FIG. 4, wherein, however, the arrangement of the feed channels 14 and 16 in the region of the coupling of the mixer 102 to the drive shaft 18 will be discussed first with reference to FIGS. 2 and 3.As can be seen in these figures, in this region the feed channels 14 and 16 and the mixing tip 100 are designed in such a way that the two substances transported by the feed channels 14 and 16 come into contact with one another only in the region of the mixer 102 within the mixing tip 100, with the result that a mixing chamber for the two substances lies completely in the region of the mixing tip 102.For this purpose, the feed channels 14 and 16 each end laterally, but at different heights with respect to the longitudinal axis L 18 of the drive shaft 18 and thus also the longitudinal axis L 102 of the mixer 102, which longitudinal axis represents an extension thereof. In this way, it is ensured that, in the manner which can be understood with reference to FIGS. 2 and 3, the two supplied substances, which are indicated by means of corresponding arrows, do not come into contact with one another outside the mixing tip 100, and therefore no contamination will also occur as a result of mixing of the two substances in the region of the body section 12. Rather, it can be seen that in the region of the input of the first substance in the opening zone of the first feed channel 14, the casing 104 or the head section 106 of the mixing tip 100 has a circumferential groove 110 and a plurality of transverse bores 112, through which the corresponding substance can enter the interior of the mixing tip 100 and mix there with the second substance added from above, so that a corresponding mixing chamber is formed in the upper section of the mixing tip 100, which mixing chamber is not bounded on any side by a component of the body section 12. For this purpose, a chamber 24 is also provided in the region of the coupling of the mixer 102 to the drive shaft 18, into which chamber the second feed duct 16 opens and which chamber is open downward in order to allow the corresponding substance to enter the mixing tip 100.As already indicated further above, the region of the coupling of the drive shaft 18 and of the mixer 102 of the mixing tip 100 is now illustrated in FIG. 4, in which region a correct coupling of these two components is ensured by self-aligning end sections.In particular, in the embodiment shown here, the end section 18 aof the drive shaft 18 is designed as a wedge-shaped section and the end section 102 aof the mixer 102 has a recess 102 band also outflow surfaces 102 c, by means of which, when the mixer 102 is pushed onto the end section 18 aof the drive shaft 18, the mixer 102 is first rotated into a suitable angular orientation until its recess 102 bis guided onto the wedge-shaped end section 18 aof the drive shaft 18, where a form-fit connection is accordingly produced. This ensures a transmission of a rotational movement of the drive shaft 18 to the mixer 102 in order to drive the latter for a corresponding rotation within the casing 104 of the mixing tip 100, as a result of which the two substances to be mixed are swirled.In order to ensure that the mixing tip 100 remains intact and, in particular, that the sleeve 104 is not pulled off the mixer 102 when the mixing tip 102 is detached from the body section 12, reference is also made to the illustration from FIG. 5, which shows a further section from the upper region of the mixing tip 100 in an enlarged illustration. It will be seen that the mixer 102 at this location has an enlarged diameter portion 102d which is received in a corresponding groove 104a on the inside of the outer shell. If the connection between the mixing tip 100 and the body section 12 is now disconnected by releasing the connecting unit 20 and the counter unit 108 from one another, in the example shown here by switching off the corresponding electromagnets, the mixing tip 100 can only be pulled off the drive shaft 18 as a whole, since a disconnection of these two components is prevented by the cooperation of the section 102 dhaving an enlarged diameter of the mixer 102 and the groove 104 aof the outer casing 104.Finally, reference is also made to FIG. 6, in which the mixing device 10 from FIGS. 1 ato 1 cis illustrated in an external view, wherein it can be seen that a vibration sensor 300 is additionally placed from the outside on the mixing tip 100, which vibration sensor is configured to check a correct state of the mixer 102 by means of an evaluation of vibration patterns.For this purpose, the vibration sensor 300 can in particular comprise its own vibration source and a detector for a vibration feedback by the mixing tip 100, from which it can be derived by means of a comparison with stored expected vibration patterns whether the mixing tip 100 and in particular the mixer 102 contained therein meet the expectation or whether, for example, a fracture of the mixer 102 is detected on the basis of a corresponding vibration response. For this purpose, the vibration sensor 300 can be connected in a suitable manner to a central control unit of the mixing device 10 or a higher-order system and supply the corresponding data thereto, so that, for example, when a defect of the corresponding mixing tip 100 is detected, the mixing device 10 can be taken out of operation in order to be able to perform a manual check or to perform a replacement or a change of the mixing tip 10 automatically.

Claims

A mixing device (10) for mixing two or more substances, comprising: - a body portion (12) in which respective feed channels (14, 16) for the first and second substances are provided; - a drive shaft (18) which extends along a longitudinal axis (L18) through the body portion (12) and is drivable for rotation about the longitudinal axis (L18); - a mixing tip (100) comprising an outer shell (104) and a mixer (102) accommodated therein; and - a connecting unit (20) assigned to the body section (12), which is configured to connect the mixing tip (100) to the body section (12) in a detachable manner by means of a counter unit (108) assigned to the mixing tip (100), wherein the mixer (102) is coupled to the drive shaft (18) in the connected state of the mixing tip (100) and can be driven in rotation by the latter; characterized in that the mixing device (10) further comprises an automatic changeover device (200), which is configured to connect a mixing tip (100) to the body section (12) in an automatic manner in a state in which no mixing tip (100) is initially connected to the body section (12).The mixing device (10) according to claim 1, wherein the changing device (200) comprises a displacement unit, in particular a 3- or 6-axis robot arm, which is configured to displace the body portion (12) along at least one axis.The mixing device (10) according to any one of the preceding claims, further comprising a magazine (202) configured to receive at least one mixing tip (100) in such a manner that it is connectable to the body portion (12) by means of the change device (200).The mixing device (10) according to any one of the preceding claims, wherein the connection unit (20) comprises at least one electromagnet and the counter unit (108) comprises at least one ferromagnetic element.Mixing device (10) according to one of the preceding claims, further comprising a connecting unit displacement device (22) which is configured to displace the connecting unit (20) with respect to the body portion (12), in particular in the direction of the longitudinal axis (L18) of the drive shaft (18).The mixing device (10) according to any one of the preceding claims, wherein the drive shaft (18) and the mixer (102) of the mixing tip (100) are provided with self-aligning end portions (18a, 102a) in the region of their coupling.The mixing device (10) according to claim 6, wherein the end section (18a) of the drive shaft (18) comprises at least one wedge-shaped section and the end section (102a) of the mixer (100) comprises at least one recess (102b) for receiving the wedge-shaped section and run-off surfaces (102c) for guiding the at least one recess (102b) onto the at least one wedge-shaped section when the mixer (102) is pushed onto the end section (18a) of the drive shaft (18).The mixing device (10) according to any of the preceding claims, wherein the mixer (102) comprises an enlarged diameter portion (102d) accommodated in a corresponding groove (104a) on the inside of the outer shell (104).Mixing device (10) according to the preamble of claim 1 and optionally the features of the characterizing part of claim 1 and / or at least one of claims 2 to 8, characterised in that the feed channels (14, 16) and the mixing tip (100) are designed such that the two substances come into contact with one another only in the region of the mixer (102), so that a mixing chamber for the two substances lies completely in the region of the mixing tip (100).The mixing device (10) according to claim 9, wherein the two feed channels (14, 16) introduce the respective substance laterally, but at different heights with respect to a longitudinal axis (L102) of the mixing tip (100), wherein at least a first of the two substances is introduced below the end of the mixer (102) with respect to the longitudinal direction (L102) of the mixing tip (100).Mixing device (10) according to claim 10, wherein in the region of the input of the first substance and / or of the second substance, the casing (104) of the mixing tip (100) has a circumferential groove (110) and a plurality of transverse bores (112).Mixing device (100) according to one of claims 10 and 11, wherein in the region of the coupling of the mixer (102) to the drive shaft (18), a chamber (24) is provided, into which the feed duct (16) of the second substance opens laterally.The mixing device (10) according to any one of the preceding claims, further comprising a vibration sensor (300) configured to check a correct state of the mixer (102) by means of an evaluation of vibration patterns.Mixing device (10) according to claim 13, wherein the vibration sensor (300) is placed or can be placed from the outside onto the sleeve (104) of the mixing head (100).The mixing device (10) according to any one of the preceding claims, wherein the mixer (102) is made of a plastic, in particular by 3d printing or injection molding.

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