3D concrete die

Description

[0001] The present invention relates to a 3D concrete printhead for two- or multi-component materials. The materials that can be processed with such a 3D concrete printhead can be concrete, mortar, or geopolymers, as well as mixtures of these materials. For example, factory-premixed dry mortars, which may also contain geopolymers, can be used. The term "3D concrete printhead" used in this description is therefore not to be understood as meaning that it can only process concrete. Rather, this term is to be understood as including the processing of the aforementioned materials.

[0002] A 3D concrete printhead must enable the continuous dispensing of an intensively mixed two- or multi-component material to ensure consistent material properties of the material dispensed. Otherwise, there is a risk that a component produced using the 3D concrete printing process would exhibit randomly varying material properties depending on its location. Furthermore, a 3D concrete printhead should be as compact and lightweight as possible to allow for quick and precise movement and, in particular, pivoting, for example, using a robotic arm.

[0003] To achieve desired properties in the material dispensed by a 3D concrete printhead, an additive is typically mixed with the concrete, mortar, or similar material that forms the base. Depending on the desired material properties, several additives can be used. Such additives include, for example, curing accelerators or retarders, color pigments, and / or substances that influence the rheological properties of the material being processed. These substances can be plasticizers, which modify the thixotropy of the material, or superplasticizers, which make a material mixture more fluid.

[0004] Regardless of the exact type of additive(s) used, it is crucial for a 3D concrete printhead to thoroughly mix the additive(s) with the base material, concrete, mortar, or similar material before the entire material is dispensed. German patent DE 10 2020 003 760 A1 discloses a 3D concrete printhead in which thorough mixing of the base concrete or mortar material with the additive(s) is ensured in the mixing chamber by introducing the base concrete or mortar material and one or more additives simultaneously but separately through a common opening in a circumferential wall of the mixing chamber. In this way, the entire length of the mixing chamber is available to thoroughly mix the materials introduced into it.

[0005] CN 208 133 209 U discloses a 3D concrete printhead for two- or multi-component materials according to the preamble of claim 1.

[0006] The invention is based on the objective of providing a 3D concrete printhead which ensures an intimate mixing of the materials used and is more compact than the 3D concrete printhead known from DE 10 2020 003 760 A1.

[0007] Based on the aforementioned prior art, this problem is solved according to the invention by a 3D concrete printhead with the features of claim 1. The 3D concrete printhead according to the invention is designed such that the concrete or mortar base material and the additive(s) used can be brought into contact and mixed with each other before entering the mixing chamber. To achieve this, an additive line, the end section of which is arranged in a material supply line leading into the mixing chamber, opens into the aforementioned material supply line through an additive opening, wherein the additive opening is located upstream of a material supply opening through which the material supply line enters the mixing chamber.The additive opening is therefore not located in the material feed opening of the mixing chamber's perimeter wall, as in the aforementioned prior art, but is set back into the material feed line and thus spaced away from the housing wall of the mixing chamber. The distance between the additive opening and the housing wall or the material feed opening should be at least approximately the same as the diameter of the material feed opening, but can also be significantly larger. The much smaller volume of the material feed line, compared to the mixing chamber, allows for better and faster mixing of the additive(s) with the concrete or mortar base material directly in the material feed line. This, in turn, makes it possible to shorten the length of the mixing chamber compared to the aforementioned prior art while maintaining the same diameter.In terms of the task at hand, this leads to a more compact and lighter 3D concrete print head, which, despite its more compact design, is able to deliver better mixing quality.

[0008] The additive line can be made of metal or plastic, for example. Preferably, the additive line, and in particular its end section, is provided with a lining that prevents material adhesion. Such a lining can be made of, for example, polytetrafluoroethylene (Teflon®). If the entire additive line, or at least its end section, is made of such a friction-reducing material, the lining of the additive line or the end section is unnecessary. Furthermore, the end of the additive line can be designed as a nozzle or be equipped with a nozzle to increase the flow velocity of the additive(s) into the material feed line and thereby achieve even better initial mixing of the additive(s) with the material already flowing in the material feed line.

[0009] According to one embodiment of the 3D concrete printhead according to the invention, the additive line can have two or more channels, each opening into the material supply line via a corresponding additive opening. In this way, two or more additives can be fed into the material supply line via a single additive line. Regardless of whether the additive line has only one or more channels, the end section of the additive line is preferably arranged concentrically to the material supply line, i.e., the cross-section of the material supply line and the cross-section of the additive line have a common center point.

[0010] Regardless of whether the end section of the additive line is arranged concentrically to the material feed line or not, it can be provided that the end section of the additive line is axially displaceable, so that the distance of the additive opening (or openings, if there are multiple channels in the additive line) from the housing wall of the mixing chamber can be varied. In this way, the distance available for mixing and homogenization in the material feed line up to the entry into the mixing chamber can be lengthened or shortened, and thus adapted to the mixing properties of the additive(s) used.

[0011] To improve mixing quality even with a short distance available for mixing and homogenization in the material supply line, some embodiments of the 3D concrete print head according to the invention incorporate a flow cross-sectional constriction in the material supply line downstream of the additive opening and upstream of the material supply opening. Such a flow cross-sectional constriction can, in particular, have the form of a Laval nozzle. The flow cross-sectional constriction leads to a locally increased flow velocity in the material supply line and thus to more intensive mixing of the additive(s) with the concrete or mortar base material in the material supply line.Alternatively or additionally, a static mixer may be present in the material supply line downstream of the additive opening and upstream of the material supply opening, which also leads to a more intensive mixing of additive(s) and concrete or mortar base material in the material supply line.

[0012] It was previously explained that an additive line can have two or more channels to allow multiple additives to be fed into the material feed line. Alternatively or additionally, several additive lines, each with its end section located within the material feed line, can be arranged so that their additive openings connect to the material feed line. These multiple additive lines can connect to the material feed line at the same point when viewed in the direction of flow. The end sections of the multiple additive lines can be arranged axially within the material feed line or project radially into it and be offset from each other circumferentially.For example, the end sections of the multiple additive lines can project radially into the material supply line in such a way that their additive openings are located near the center of the material supply line. All additives fed into the material supply line via such additive lines then meet in the core area of ​​the flow running through the material supply line and are thus intensively mixed with each other and with the concrete or mortar base material flowing in the material supply line immediately after their introduction.

[0013] Alternatively, the end sections of the multiple additive lines can project tangentially into the material feed line, and they can also be arranged offset from each other in the circumferential direction of the material feed line. Such a tangential injection of additive(s) into the material feed line can impart a swirl to the flow in the material feed line, which intensifies the mixing and thereby improves the mixing quality. It is also possible to configure the system in which some end sections of the multiple additive lines project radially into the material feed line and other end sections project tangentially into the material feed line.

[0014] Depending on the properties of the additives used, it may be advantageous not to introduce all or any of the additives into the material supply line at the same point in the flow direction. This applies, for example, if certain additives are not readily compatible with each other and therefore must first be mixed individually with the concrete or base material. To achieve this, certain embodiments of the 3D concrete printhead according to the invention are characterized by the fact that the additive openings of the multiple additive lines are arranged one after the other in the flow direction of the material supply line. The additive openings of the multiple additional lines are thus axially spaced apart from each other in the material supply line.As previously explained, the end sections of the multiple additive lines can project radially or tangentially into the material supply line and are preferably arranged offset from each other in the circumferential direction of the material supply line.

[0015] In other embodiments of the 3D concrete printing head according to the invention with multiple additive lines, the end sections of the multiple additive lines are arranged axially and one behind the other in the material supply line. This also ensures that the additive openings of the multiple additive lines are axially spaced apart from one another in the material supply line. In the latter embodiment, a static mixer or a flow cross-sectional constriction can be provided between two additive openings of the multiple additive lines that are successive in the flow direction of the material supply line in order to intensify the mixing and homogenization process and thereby improve the mixing quality. As already explained, the flow cross-sectional constriction can, in particular, have the shape of a Laval nozzle.

[0016] Due to its many possible variations, the design of the 3D concrete printhead according to the invention can be specifically tailored to any application and any material combination to be processed. Furthermore, in every embodiment, the 3D concrete printhead according to the invention ensures excellent mixing and homogenization of the material used and, due to its compact and lightweight design, is very easy to handle, which in particular reduces the demands placed on handling robots. Embodiments of the 3D concrete printhead according to the invention are explained in more detail below with reference to the exemplary schematic drawings. These show: Fig. 1 a partial longitudinal section through a first embodiment of a 3D concrete printhead according to the invention, Fig. 1 the view AA from Fig. 1 with an additive line having a channel, arranged concentrically in a material supply line, Fig. 1b, view AA from Fig. 1 with an additive line having two channels, arranged concentrically in the material supply line, Fig. 1c, view AA from Fig. 1 with three additive lines arranged circumferentially offset and projecting radially into the material supply line, Fig. 1d view AA from Fig. 1 with two radially projecting and opposing additive lines into the material supply line, Fig. 1e the view AA from Fig. 1 with two opposing additive lines projecting tangentially into the material supply line, Fig. 2 a detailed view of a modification of the in Fig. 1 The embodiment shown, Fig. 3, is a detailed view of a further modification of the one described in Fig. 3. Fig. 1 Figure 4 shows a partial longitudinal section through an embodiment with a flow cross-sectional narrowing in the material supply line, Figure 5 shows a partial longitudinal section of an embodiment with a static mixer in the material supply line, Figure 6 shows a partial longitudinal section of an embodiment with three additive lines arranged axially one behind the other in the material supply line, and Figure 7 shows a partial longitudinal section of an embodiment with two additive lines arranged axially one behind the other in the material supply line and a static mixer arranged between them.

[0017] Fig. 1 Figure 1 shows a first embodiment of a 3D concrete printhead 10 for dispensing concrete, mortar, or the like in a partially longitudinal section. The 3D concrete printhead 10 has a housing 12 with a mixing chamber 14 arranged therein, which is bounded by a housing wall 16. The terms "above," "above," "below," "below," and "side" used in connection with the accompanying figures are not to be understood as absolute, but refer only to the representation of the 3D concrete printhead 10 shown in the figures. It is understood that a 3D concrete printhead 10 can assume any desired and necessary orientation during operation.

[0018] In the illustrated embodiments, the mixing chamber 14 has a circular cylindrical shape and can therefore also be referred to as a mixing tube.

[0019] The mixing chamber 14 extends axially along a longitudinal axis L from an upper end 18 of the mixing chamber 14 (as shown in the figures) to a lower end formed by a mixing chamber outlet opening 20. Specifically, the mixing chamber 14 extends between a material supply opening 19, arranged laterally here, and the mixing chamber outlet opening 20. The material supply opening 19 serves to introduce concrete, mortar, or the like into the mixing chamber 14. Although in all embodiments shown here the material is introduced into the mixing chamber 14 in a circumferential region of the housing wall 16, it is also possible to arrange the material introduction in an end-face region of the housing wall 16, for example, at the upper end 18 of the mixing chamber 14 (not shown).If necessary, the upper end 18 of the mixing chamber 14 must be made slightly wider compared to the illustrated embodiments in order to create enough space at the upper end 18 of the mixing chamber 14 for a material supply opening 19.

[0020] In the mixing chamber 14 is an actively driven mixing device, here in the form of a mixing unit 22 with a mixing shaft 24 extending axially through the mixing chamber 14, to which several radially outwardly projecting mixing vanes 26 are attached. An electric motor 28 is connected to the upper end of the mixing shaft 24 and serves to rotate the mixing shaft 24 and thus the entire mixing unit 22, causing the mixing shaft 24 to rotate about the longitudinal axis L. Instead of the electric motor 28 shown here, the mixing shaft 24 can also be driven mechanically, pneumatically, or hydrodynamically in other ways. Likewise, the illustrated mixing unit 22 is merely an example. Any other mixing unit or mixing device that achieves the desired mixing in the mixing chamber 14 can be used instead of the mixing unit 22 shown.

[0021] Below the mixing chamber 14, a discharge component 30 is arranged, which forms a discharge opening 32 of the 3D concrete print head 10 at its lower, free end. In the embodiments shown here, the discharge component 30 is attached to the housing 12 and can have a flow cross-section that narrows conically in the direction of flow. As shown, the mixing chamber outlet opening 20 of the mixing chamber 14 is in flow-conducting communication with the discharge component 30 and thus also with the discharge opening 32, so that during operation of the 3D concrete print head 10, material from the mixing chamber 14 can be discharged through the discharge opening 32.

[0022] To introduce material to be dispensed into the mixing chamber 14, the material feed opening 19 of the mixing chamber 14 is connected to a material feed line 34, which extends outwards from the material feed opening 19 and can be designed, for example, as a feed pipe and / or a feed hose. The main components of a material mixture to be dispensed by the 3D concrete printhead are supplied to the mixing chamber 14 via the material feed line 34. For example, the material feed line 34 can be directly connected to a concrete or mortar mixing device (not shown), wherein the concrete or mortar mixing device produces concrete or mortar, or the like, and forces it through the material feed line 34 into the mixing chamber 14 of the 3D concrete printhead 10.

[0023] For the successful application of a 3D concrete printing process, it is generally necessary to add one or more additional substances to the material to be processed, which is fed into the mixing chamber 14 via the material feed line 34, in order to precisely adjust the properties of the material mixture to be applied with the 3D concrete print head 10. These additional substances are referred to here as additives.

[0024] To introduce such additional substances into the material to be processed by the 3D concrete printhead 10, at least one additive line 36 with an end section 38 arranged in the material supply line 34 is used. The end section 38 has an additive opening 40 through which the additive line 36 opens directly into the material supply line 34. To ensure that an additive supplied through such an additive line 36 can mix with the material flowing through the material supply line 34 before entering the mixing chamber 14, the additive opening 40 is arranged upstream of the material supply opening 19 in the direction of flow of the material flowing through the material supply line 34. In other words, the additive opening 40 is located upstream of the material supply opening 19 at a distance X from the housing wall 16 of the mixing chamber 14.This distance X is dimensioned such that the material flowing through the material feed line 34 (now including the additive(s)) is sufficiently mixed along this distance X before entering the mixing chamber 14. The distance X should be at least approximately the same size as the diameter of the material feed opening 19; however, the distance X can also be several times the diameter of the material feed opening 19, for example, two, three, four, or five times the stated diameter. Even larger distances X are also possible in principle. In the mixing chamber 14, the material mixture entering through the material feed opening 19 is then further mixed and homogenized.

[0025] In the Fig. 1 In the illustrated embodiment, the additive line 36 enters the material supply line 34 laterally and is then guided such that the end section 38 of the additive line 36 is axially aligned within the material supply line 34, i.e., in the flow direction of the material flowing in the material supply line 34. However, the additive line 36 can also be introduced into the material supply line 34 differently than shown, for example, from the rear (not shown).

[0026] The Figuren 1a bis 1e Each shows the AA view. Fig. 1 for various configurations of the arrangement of one or more additive lines 36 in the material supply line 34. Fig. 1a essentially corresponds to the one in Fig. 1 In the illustrated embodiment, the additive line 36 has only a single channel 42 for supplying an additive into the material supply line 34. According to this embodiment, the end section 38 of the additive line 36 is arranged concentrically to the cross-section of the material supply line 34, i.e., an end face 44 of the end section 38 encompassing the additive opening 40 and the circular cross-section of the material supply line 34 have the same center point.

[0027] The end section 38 of the additive line 36 does not necessarily have to be centered in the material supply line 34, but can also be arranged eccentrically in the material supply line 34 (not shown). The material supply line 34 also does not need to have a circular cross-section.

[0028] Fig. 1b shows one of the Fig. 1a similar embodiment, however, the additive line 36' has, in contrast to the Fig. 1a The cross-section is not circular, but rectangular. Furthermore, the additive line 36' contains two channels 46, 48, each with an additive opening 40', 40", so that, according to this embodiment, two additives can be introduced into the material supply line 34. The end section 38 of the additive line 36' is analogous. Fig. 1 axially aligned in the material supply line 34 and centered on the midpoint of the cross-section of the material supply line 34. As previously described for Fig. 1a As explained, an eccentric arrangement is also possible here (not shown).

[0029] Fig. 1c Figure 1 illustrates another embodiment in which three additive lines 36a, 36b, and 36c, each with their associated end section 38, project radially into the material supply line 34. The additive lines 36a, 36b, and 36c are arranged offset from one another in the circumferential direction of the material supply line 34, in the illustrated embodiment by 120° each, but viewed axially, they all enter the material supply line 34 at the same point. Fig. 1c Three different additives can be introduced into the core of a flow in the material supply line 34. These three additives immediately mix upon exiting their respective additive lines 36a, 36b, and 36c through the additive openings 40a, 40b, and 40c, respectively, due to their mutual collision. According to a modified embodiment (not shown here), the additive lines 36a, 36b, and 36c are arranged offset axially along the material supply line 34 and no longer enter the material supply line 34 at the same point. This modified embodiment may also include an offset of the additive lines 36a, 36b, and 36c circumferentially along the material supply line 34, but this offset may also be omitted.

[0030] Fig. 1d shows one of the Fig. 1c A similar embodiment with only two additive lines 36a, 36b, which are arranged opposite each other according to this embodiment. A non-opposite arrangement of the additive lines 36a, 36b is also possible (not shown). Otherwise, the provisions regarding Fig. 1c As explained above, in an analogous manner, i.e. the two additive lines 36a, 36b can enter the material supply line 34 at the same point or at axially spaced points with respect to the axial direction of the material supply line 34.

[0031] Fig. 1e Figure 1 shows a further modified embodiment in which the end sections 38 of two additive lines 36a, 36b project tangentially into the material supply line 34 and are arranged offset from each other in the circumferential direction of the material supply line 34. With such a tangential arrangement of the end sections 38 of the additive lines 36a and 36b, the introduced additives no longer collide directly with each other in the core of a flow passing through the material supply line 34. Rather, such an arrangement of the end sections 38, tangential to the cross-section of the material supply line 34, imparts a swirl to the flow in the material supply line 34, which promotes thorough mixing of the introduced additives with each other and also with the material located in the material supply line 34.As previously explained, the end sections 38 can also be arranged at the same axial position on the material supply line 34 or can be axially spaced apart from each other. Instead of the one in . Fig. 1e In addition to the two additive lines 36a and 36b shown, there can also be several additive lines with such a tangential arrangement, particularly if the inlet points to the material supply line 34 are axially spaced apart, and of course, there can also be only a single additive line with a tangential arrangement. Furthermore, the Fig. 1c bis Fig. 1e The embodiments shown can be combined with one another; that is, some additive lines can enter the material supply line 34 at the same axial location, and other additive lines can be axially spaced from this axial location and, if desired, also from each other. Furthermore, some end sections 38 of the additive lines can have a tangential arrangement as shown in Fig. 1e illustrated, and other end sections can be arranged radially. A combination with those shown in Fig. 1a und Fig. 1b The illustrated embodiments are possible, i.e., for example, one or two additives can be replaced by the ones shown. Fig. 1a oder Fig. 1b The materials shown in the arrangements are introduced into the material supply line 34, while further additives are supplied via arrangements as shown in the Figuren 1c bis 1e are illustrated.

[0032] Fig. 2 shows a further embodiment of an additive line 36', the arrangement of which is basically the same as in Fig. 1 The arrangement shown corresponds to that shown. As in Fig. 1b The additive line 36' shown also has the in Fig. 2 The additive line shown has two channels, 46 and 48, however, in the Fig. 2 In the embodiment shown, these channels 46 and 48 are arranged concentrically to each other. Channel 46 has a circular flow cross-section, whereas channel 48 has an annular flow cross-section.

[0033] Fig. 3 shows a opposite Fig. 2 A modified embodiment in which the end section 38 of the additive line 36 is axially displaceable. As indicated by arrow P, the distance X of the additive opening 40 from the housing wall 16 or the material feed opening 19 can be changed in this way. This makes it possible to adapt the distance X, at least within certain limits, to the mixing properties of a supplied additive and, for example, to provide such an additive with a longer distance X for mixing with the material flowing in the material feed line 34. If a bearing arrangement 50, 52 as in Fig. 3 If the units are provided with flow openings 54, then the space concentrically surrounding the additive line 36 can be described as in the embodiment shown. Fig. 2 can be used to supply another additive to the material supply line 34.

[0034] Fig. 4 shows an arrangement similar to that in Fig. 1 The illustrated embodiment features a flow cross-sectional constriction in the material supply line 34, arranged downstream of the additive opening 40 and upstream of the material supply opening 19. In this embodiment, the flow cross-sectional constriction has the form of a Laval nozzle 56. Any flow cross-sectional constriction, and in particular a Laval nozzle, increases the flow velocity in the region of the constriction, thereby intensifying the mixing of an additive supplied through the additive line 36 with the material flowing in the material supply line 34. If the Laval nozzle 56 is arranged near the material supply opening 19 as shown, then such a Laval nozzle also achieves an accelerated flow of the material mixture flowing in the material supply line 34 into the mixing chamber 14, which also contributes to better mixing.

[0035] Fig. 5 shows a modified embodiment in which, instead of the one in Fig. 4 In the Laval nozzle 56 shown, a static mixer 58 is arranged downstream of the additive opening 40 and upstream of the material feed opening 19 in the material feed line 34. Such a static mixer leads to a thorough mixing of the additive fed into the material feed line 34 with the material already flowing in the material feed line 34 over a relatively short distance.

[0036] Fig. 6 shows a similar embodiment Fig. 1 , however, according to Fig. 6 Three additive lines 36a, 36b, 36c are arranged such that their end sections 38 are arranged axially and one behind the other in the material supply line 34. In other words, the end sections 38 follow one another in the axial direction when viewed in the flow direction of the material supply line 34.

[0037] Fig. 7 Finally, one of the Fig. 6 A similar embodiment with only two additive lines 36a and 36b, wherein a static mixer 58 is arranged between the two additive openings 40b and 40a of the additive lines 36b and 36a, which are successive in the flow direction of the material supply line 34, in order to effect intimate mixing of an additive introduced through the additive line 36b with the material flowing in the material supply line 34. Such a static mixer, or alternatively a flow cross-sectional constriction, can of course also be used in the Fig. 6 as illustrated embodiment, possibly also several times, i.e. after one or more or all additive openings 40a, 40b and 40c.

Claims

1. 3D concrete printhead (10) for two- or multi-component materials, having - a housing (12), and a mixing chamber (14) arranged in the housing and delimited by a housing wall (16), - a material supply line (34) having a material supply opening (19) which opens into the mixing chamber (14), - at least one additive line (36) having an end portion (38), - a mixing device which is arranged in the mixing chamber (14) and can be actively driven, - a mixing chamber outlet opening (20), the mixing chamber (14) extending along a longitudinal axis (L) at least between the material supply opening (19) and the mixing chamber outlet opening (20), and - a discharge opening (32) which is in fluidic communication with the mixing chamber outlet opening (20), wherein - the at least one additive line (36) opens into the material supply line (34) through an additive opening (40), the additive opening (40) being located upstream of the material supply opening (19) and being at a distance (X) from the housing wall (16) of the mixing chamber (14), characterised in that the end portion (38) of the additive line (36) is arranged in the material supply line (34).

2. 3D concrete printhead according to claim 1, characterised in that the additive line (36') comprises two or more channels (46, 48), each of which opens into the material supply line (34) via an additive opening (40', 40").

3. 3D concrete printhead according to claim 1 or 2, characterised in that the end portion (38) of the additive line (36, 36') is arranged concentrically with the material supply line (34).

4. 3D concrete printhead according to any one of the preceding claims, characterised in that the end portion (38) of the additive line (36) is mounted so as to be axially displaceable such that the distance (X) of the additive opening (40) from the housing wall (16) of the mixing chamber (14) is variable.

5. 3D concrete printhead according to any one of the preceding claims, characterised in that there is a flow cross section constriction, in particular in the form of a Laval nozzle (56), in the material supply line (34) downstream of the additive opening (40) and upstream of the material supply opening (19).

6. 3D concrete printhead according to any one of the preceding claims, characterised in that there is a static mixer (58) in the material supply line (34) downstream of the additive opening (40) and upstream of the material supply opening (19).

7. 3D concrete printhead according to any one of claims 1 to 3, characterised in that multiple additive lines (36a, 36b, 36c), the end portions (38) of which are each arranged in the material supply line (34), open with their additive openings (40a, 40b, 40c) into the material supply line (34).

8. 3D concrete printhead according to claim 7, characterised in that the multiple additive lines (36a, 36b, 36c), as seen in the flow direction of the material supply line (34), open into the material supply line (34) at the same point.

9. 3D concrete printhead according to claim 8, characterised in that the end portions (38) of the multiple additive lines (36a, 36b, 36c) project radially into the material supply line (34) and are arranged offset with respect to one another in the circumferential direction of the material supply line (34).

10. 3D concrete printhead according to claim 8, characterised in that the end portions (38) of the multiple additive lines (36a, 36b) project tangentially into the material supply line (34) and are arranged offset with respect to one another in the circumferential direction of the material supply line (34).

11. 3D concrete printhead according to claim 7, characterised in that the additive openings (40a, 40b, 40c) of the multiple additive lines (36a, 36b, 36c) are arranged one behind the other as seen in the flow direction of the material supply line (34).

12. 3D concrete printhead according to claim 11, characterised in that the end portions (38) of the multiple additive lines (36a, 36b, 36c) project radially or tangentially into the material supply line (34) and are preferably arranged offset with respect to one another in the circumferential direction of the material supply line (34).

13. 3D concrete printhead according to claim 7, characterised in that the end portions (38) of the multiple additive lines (36a, 36b, 36c) are arranged in the material supply line (34) axially and one behind the other.

14. 3D concrete printhead according to claim 13, characterised in that a static mixer (58) or a flow cross section constriction, in particular in the form of a Laval nozzle (56), is arranged in the material supply line (34) between two additive openings (40a, 40b, 40c) of the multiple additive lines (36a, 36b, 36c) that follow one another in the flow direction of the material supply line (34).