Mixing head

Abstract

The invention relates to a mixing head for processing a plurality of components (K1, K2, K3,...) in order to form a mixture, in particular a mixture of a reaction plastic, and for discharging the mixture, comprising a mixing chamber and a plurality of injection channels connected to the mixing chamber, wherein each of the components can be introduced into the mixing chamber via one the injection channels. According to the invention, at least one component feed switching device through which two or more components can flow is provided, the component feed switching device having an outlet as a feed connection, which is or can be fluidically connected to an injection channel. The component feed switching device is designed such that a component can be selected which can be supplied to the feed connection. Furthermore, at least one component return switching device with an analog design is provided. Both switching devices can be combined in a component switching block (5).

Description

[0001] 77774-WO-KMT / Wl-Wl 15.01.2026

[0002] Description

[0003] Mixing head

[0004] The invention relates to a mixing head according to the preamble of claim 1.

[0005] Mixing heads for processing reactive or polymeric components for the production of mostly thermoset materials, especially polyurethane, are known in various designs. In such mixing heads, at least two reactive starting materials are intimately mixed together in a mixing chamber, and the mixture is then discharged from the mixing chamber.

[0006] Document DE 195 15 039 A1 discloses a device for mixing at least two chemically reactive plastic components under high pressure, comprising a cylindrical mixing chamber into which the components are injected, and a reversible piston arranged within the mixing chamber for discharging residual plastic mixture. The device also includes a cylindrical settling chamber / discharge chamber / discharge channel adjoining the mixing chamber and extending at an angle of preferably 90° to the longitudinal axis of the mixing chamber, wherein a reversible cleaning piston is arranged in the settling chamber for discharging the reactive plastic mixture from the settling chamber. The cleaning piston has recesses on its cylindrical surface, which are filled with spacer material and arranged in a spiral pattern on the surface, such that axial movement of the cleaning piston causes it to rotate.This leads to an interruption of the cylinder surface during axial movement of the piston and thus serves as wear protection.

[0007] Document EP1979143A1 discloses a mixing head with recirculation grooves in the control piston. These recirculation grooves serve to ensure recirculation of the starting material, i.e., a return flow of the starting materials to the output container, in a forward switching position that closes the mixing chamber (recirculation state). Such recirculation via these recirculation grooves is known per se and requires no further explanation. In a retracted switching position of the control piston, the mixing chamber is released, the starting materials can mix with each other, and are then discharged from the mixing chamber (discharge phase).

[0008] In a simple embodiment, mixing heads typically have one connection for a polyol component and one for an isocaynant component. Each of these connections includes a supply port and a return port. The respective component can be fed via the supply port to an injection channel, in particular an injection nozzle, from where it enters the mixing chamber. If no material discharge from the mixing chamber is desired, the components flow back into their respective storage containers via recirculation grooves and the return port (recirculation state).

[0009] Furthermore, mixing heads are known that can process more than two components. Each component has its own component connection block, which is fluidically connected to the mixing chamber. Due to the design constraints, the number of component connection blocks that can be attached to the mixing head, and therefore the number of components that can be processed, is limited.

[0010] Based on this, the invention aims to provide a mixing head suitable for an increased number of processable components.

[0011] This problem is solved by a mixing head with the features of dependent claims 1 and 6. Advantageous embodiments and further developments are found in the dependent claims. 77774-WO-KMT / Wl-Wl 15.01.2026

[0012] According to a first core concept of the present invention, at least one component feed switching device, through which fluid flows from two or more components, is provided. Such a component feed switching device has an outlet as a feed connection, which is fluid-connected or connectable to an injection channel. The component feed switching device is designed such that a component can be selected which can be supplied to the feed connection. Such a component feed switching device can be arranged directly on the mixing head, in particular on the head section of the mixing head. However, it can also be spaced apart from it, with the necessary fluid connections to the mixing head or the head section of the mixing head being established via suitable pipes or hoses.

[0013] According to one embodiment of the aforementioned first core concept, a component switching block through which two components can flow is provided as a component feed switching device. Functionally, such a component switching block corresponds to a component connection block for a single component, but allows the alternating supply of two different components to an injection channel, in particular an injection nozzle, connected to the mixing chamber. During operation, the mixing chamber of the mixing head can thus be supplied with one or the other component via the component switching head, as required. This component switching block comprises a feed section (VL) with two feed channels, namely a first feed channel for a first component and a second feed channel for a second component. The two feed channels are connected at a feed connection of the feed section (VL).Furthermore, a supply valve is provided, which can selectively open the flow path to the supply connection for either of the two components, with a fluid connection provided between the supply connection and one of the injection channels. A line or channel can be provided between the supply connection and an injection nozzle, allowing the component arriving at the supply connection to flow to the injection nozzle connected to this supply connection and from there into the mixing chamber.

[0014] Advantageously, the flow control valve can be designed as a double seat valve with two switching positions, namely a first switching position in which the first component can flow to the flow connection and at the same time the flow path of the second component to the flow connection is blocked, and a second switching position in which the second component can flow to the flow connection and at the same time the flow path of the first component to the flow connection is blocked.

[0015] In order to ensure that the desired component can reach the mixing chamber without a long flow path and in a short time, the flow path of the components from the outlet of the supply connection to the inlet of the mixing chamber can be less than 1200 mm, preferably less than 800 mm and most preferably less than 200 mm.

[0016] Preferably, the supply connection can be directly connected to an injection channel connected to the mixing chamber.

[0017] According to a second key concept of the present invention, at least one component return switching device, through which flow is possible between two or more components, is provided. The component return switching device is designed such that switching between the component returns is possible in such a way that a selected component return is fluidly connected to a recirculation device of the mixing head.

[0018] According to one embodiment of the aforementioned second core concept, a component changeover block through which flow can be passed by two components is provided as a component return switching device. This component changeover block comprises a return section (RL) with two return channels, namely a first return channel for a first component and a second return channel for a second component. The two return channels are joined at a return port of the return section. Furthermore, a return switching valve is provided, with which the flow path of the component flowing back from the recirculation device to the component changeover block can be opened from the return port into the return channel assigned to that component.

[0019] Preferably, the return switching valve is designed as a double seat valve with two switching positions, namely a first switching position in which the first component can flow from the return port via the first return channel to the return line of the first component and at the same time the flow path of the second component from the return port via the second return channel to the return line of the second component is blocked, and a second switching position in which the second component can flow from the return port via the second return channel to the return line of the second component and at the same time the flow path of the first component from the return port via the first return channel to the return line of the first component is blocked.

[0020] According to an advantageous embodiment of the invention, a mixing head can be configured with a component feed switching device and a component return switching device. In this respect, such an embodiment corresponds to a combination of the features of dependent claims 1 and 6.

[0021] A mixing head can have at least one flow switching valve in the component flow switching device and at least one return switching valve in the component return switching device. Such a flow switching valve can be designed as a double-seat valve or as a double spool valve. Likewise, the return switching valve can be designed as a double-seat valve or as a double spool valve. The double-seat valve is preferably designed as a double needle seat valve, double cone seat valve, double ball seat valve, or double disc seat valve. The aforementioned valve variants allow the design of a switching device to be kept comparatively simple. In particular, double-seat or double spool valves have the advantage that by simply switching between two end positions, one valve opening is opened while the other valve opening is simultaneously closed, and vice versa.

[0022] A first drive for actuating the flow control valve and a second drive for actuating the return control valve can be provided, with both drives preferably being designed as hydraulic drives.

[0023] According to an advantageous embodiment, a hydraulic actuator can be provided for both the flow control valve and the return control valve, wherein the two hydraulic actuators can be operated simultaneously via a common hydraulic valve, such that the flow control valve and the return control valve are actuated simultaneously, in particular to the same switching position. This embodiment is characterized by low complexity and a relatively small design.

[0024] However, it is also possible for the two actuators to be operated independently. In this case, hydraulic actuators can also be used for the flow control valve and the return control valve. The hydraulic actuators can be switched independently of each other. This makes it possible to provide a certain time offset between the flow control valve and the return control valve. For example, the flow control valve switches first, and the first component still present in the mixing chamber can be fed into the return line of the first component until the incoming second component has reached the mixing chamber or at least partially filled it. After a time offset, when all of the first component has entered the return line, the return control valve switches over, so that the second component can now flow into the return line when the mixing head enters recirculation mode. 77774-WO-KMT / Wl-Wl 15.01.2026 Other types of drives can also be provided as drives, such as: pneumatic drive, electric, electromagnetic or mechanical drive.

[0025] According to an advantageous embodiment, a component feed switching device and a component return switching device can be combined in a one-piece component switching block, such that a feed section (VL) and a return section (RL) are connected to or combined in one block. This block can be provided on the mixing head, preferably being attached to the mixing head such that the feed connection of the feed section (VL) and / or the return connection of the return section (RL) are directly connected to an injection channel.

[0026] In the aforementioned advantageous embodiment, a component switching block thus comprises a supply section (VL) and a return section (RL). The supply section contains the two supply channels and the supply switching valve for the switchable supply of two components to the supply connection. The return section contains the two return channels and the return switching valve for the switchable discharge of the two aforementioned components coming from the mixing chamber into their respective return lines.

[0027] The component switching block can be designed as a single piece, such that the supply section (VL) and the return section (RL) are connected or combined into a single block. This block is provided on the mixing head, preferably in such a way that the supply connection and / or the return connection are directly connected to an injection channel. However, the supply section (VL) and the return section (RL) can also be designed as separate components. This allows the supply section (VL) and the return section (RL) to be attached to the mixing head in a spatially separate manner. In particular, whether a component switching block (77774-WO-KMT / Wl-Wl 15.01.2026) or a component switching device should be designed as a single piece or as two pieces depends on the design of the mixing head and on the possibilities for connecting the supply and return lines to the injection nozzle of the mixing head.

[0028] The mixing head can be designed as a high-pressure mixing head and comprises a mixing chamber in which a control piston can be moved between at least two positions, namely a first position as a discharge position in which the mixture can be discharged from the mixing chamber into the molding tool, and a second position as a recirculation position in which the supply of components to the mixing chamber is interrupted and the components flowing to the mixing chamber can flow back into their associated storage containers.

[0029] The mixing head can also be designed as a low-pressure mixing head, comprising a mixing chamber in which means for mixing the components are provided, in particular a rotating stirrer.

[0030] According to a further embodiment of the invention, the component feed switching device can be designed as a switching valve block, wherein the switching valve block has a number of inlets corresponding to the number of components and one outlet, which forms the outlet of the component feed switching device. The switching valve block has a check valve for each of the components, which is fluid-connected to the outlet of the switching valve block on the outlet side. A selected component can be activated, which can then flow to the outlet of the switching valve block via the check valve assigned to that component.

[0031] One or more of the injection channels can be configured as injection nozzles. A pressure compensation device can be provided for at least one of the injection nozzles to compensate for changes in viscosity or quantity, in particular a spring-loaded nozzle needle or a nozzle needle pre-tensioned with compressed air. 77774-WO-KMT / Wl-Wl 15.01.2026 A component switching device or a component switching block can be used for similar components, for example, for a polyol 1 and a polyol 2. The isocyanate component can be supplied via a separate component connection block. Depending on the application, a polyol 1 can be a catalyst with a low emission rate in the final product (low emission catalyst) and a polyol 2 a standard catalyst for a lower-priced final product.

[0032] A mixing head according to the invention preferably comprises a head section and a mixing chamber assembly arranged in the head section. The mixing chamber assembly has at least one mixing chamber and at least two inlets for introducing starting material or components to be mixed into the mixing chamber. The mixing head is intended for the production of reactive polymers. Furthermore, an outlet is provided through which the mixture of components or starting materials can be discharged from the mixing chamber. A control piston is movably arranged in the mixing chamber. The mixing chamber assembly is preferably detachably arranged in the head section to allow for replacement. A transition fit and, additionally or alternatively, a clearance fit can be formed between the head section and the mixing chamber assembly.

[0033] Furthermore, the mixing head preferably has at least two recirculation outlets. Each inlet for the introduction of components or starting material is assigned a recirculation outlet. The mixing head, and in particular the control piston of the mixing head, is shaped such that, in the closed position, a fluid connection exists between the inlet and the assigned recirculation outlet, allowing recirculation of the starting material introduced via the inlet to the assigned recirculation outlet. The mixing head thus has at least one recirculation outlet per inlet, which, in the closed position of the control piston, are connected to the respective assigned inlet for recirculation. 77774-WO-KMT / Wl-Wl 15.01.2026 The mixing head can be a mixing head for a reaction casting machine for the production of reactive plastics.This could be a polyurethane foaming system designed for the production of reactive plastics, such as polyurethane foams. Reactive plastics generally consist of two (reactive) components (base and hardener) and possibly other additives, and harden through a chemical reaction between them. The components, particularly the reactive ones, can be considered the starting material. A component of the surrounding atmosphere can also react. The mixture can be prepared immediately before application, at which point the hardening process begins. The reactive plastic in its processable state before chemical hardening is referred to as a reactive resin. Examples of reactive plastics include epoxy resin (EP), polyurethane (PU / PUR), nylon or polyamide (thermoplastic – but produced in the mixing head as a polyaddition reaction), DPCD (dicyclopentadiene / polyester), or unsaturated polyesters (UP).

[0034] In particular, a mixing head according to the invention can be used for the production of polyurethane (PUR). The basic components of the PUR material are polyol and isocyanate, with mixtures of different polyols being particularly suitable for use on the polyol side. The processing of such a multi-component reaction system can be described as reaction casting. If the reaction mixture additionally contains a blowing agent and is thus capable of foaming, it can also be described as reaction foam casting. The mixing head is preferably based on the countercurrent injection principle and utilizes the mixing effect of turbulent flow. The supplied components can be subjected to a pressure of over 50 bar, particularly between 100 bar and 250 bar.

[0035] The invention will now be described in more detail using an exemplary embodiment and with reference to the figures. The figures show:

[0036] Fig. 1 perspective view of a mixing head according to the invention;

[0037] Fig. 2 Section through a component switching block; 77774-WO-KMT / Wl-Wl 15.01.2026 Fig. 3 Head section of a mixing head with connected component switching block in a sectional view and during operation with a first component (K6);

[0038] Fig. 4 Head section of a mixing head with connected component switching block in a sectional view and during operation with a second component (K7);

[0039] Fig. 5 shows an embodiment of a component pre-run switching device with a switching valve block.

[0040] Figure 1 shows a perspective view of a mixing head which, in a manner known per se, comprises a cleaning piston hydraulic cylinder 1 for actuating a cleaning piston movable therein. The cleaning piston can be moved between a retracted, rear end position and a forward end position by actuating the hydraulic cylinder. For this purpose, a hydraulic connection 1A is provided for moving to the rear end position and a hydraulic connection 1B for moving to the forward end position. In the mixing chamber (not visible here), a control piston is movable between a first open position and a second closed position. In the open position, one or more components can enter the mixing chamber, whereas in the closed position no component can enter the mixing chamber.A hydraulic control cylinder 2 with hydraulic connections 2A and 2B is provided for moving the control piston. The control piston can be moved to the closed position via hydraulic connection 2A. The control piston can be moved to the open position via hydraulic connection 2B. The injection nozzles are controlled via hydraulic connections 3 and 4. The mixing head has a component connection block for each of the five components K1 to K5, with connections for the supply and return lines and an injection nozzle. The return line for K2 is concealed and not visible in the figure.

[0041] According to the invention, a component switching block 5 is also provided on the mixing head, via which two further components K6 and K7 are alternately supplied to the mixing chamber and, in the recirculation state, can flow back into their storage containers. According to a preferred embodiment, two double-seat valves are hydraulically movable between two switching positions in the component switching block. For this purpose, two hydraulic connections 5A and 5B are provided on the component switching block. Details of the design and operation of such a component switching block 5 are explained in more detail below with reference to Figures 2 to 4.

[0042] The component switching block 5 shown in Figure 2 has two ports 7 and 8 through which a fluidic connection to the mixing chamber can be established, or already exists. A first port 7 serves as the supply port and a second port 8 as the return port. The component switching block 5 can be conceptually divided into two parts: a supply section VL, located to the right of line A, and a return section RL, located to the left of line A. Accordingly, the supply port 7 belongs to the supply section VL and the return port 8 to the return section RL of the component switching block 5. In the embodiment described here, the component switching block 5 is formed in one piece, such that the supply section VL and the return section RL are connected or combined into a single block.This block is provided on the mixing head, preferably mounted such that the supply and / or return connections are directly connected to an injection nozzle. In principle, the supply section (VL) and the return section (RL) can also be designed as separate components. This allows the supply and return sections to be mounted separately on the mixing head. Whether the component switching block is designed as a single piece or two pieces depends in particular on the design of the mixing head and the possibilities for connecting the supply and return lines to the injection nozzle of the mixing head.

[0043] In the supply section VL of the component switching block 5, two supply channels 9a and 9b are provided, which are joined at the supply connection 7, namely a first supply channel 9a for a first component and a second supply channel 9b for a second component. The two components are supplied via component supply connections 10a and 10b. For example, component K6 can be supplied via component supply connection 10a, specifically via the supply line K6 located at component supply connection 10a (see Figure 1). Component K7 can thus be supplied via component supply connection 10b, specifically via the supply line K7 located at component supply connection 10b (see Figure 1). The supply channels 9a and 9b are separated from each other by a supply switching valve 11, which in this case is designed as a double cone seat valve.The two valve bodies 12a and 12b are equipped with conical sealing surfaces 13a and 13b. Furthermore, the two valve bodies 12a and 12b are connected to each other by a piston rod 14, which runs through a hydraulic cylinder 15 and is equipped with a hydraulic piston 16. In the depressurized state, the hydraulic piston 16 is held in the position shown here by a preload spring 17. This position can also be referred to as the default position of the flow control valve 11. The hydraulic piston 16 is pressurized with hydraulic fluid via hydraulic ports 18a and 18b.By pressurizing the hydraulic piston 16 with pressurized fluid, the supply switching valve 11 can be moved between two switching positions: a first switching position in which component K6 can flow to the supply port 7 and simultaneously the flow path of component K7 to the supply port 7 is blocked, and a second switching position in which component K7 can flow to the supply port 7 and simultaneously the flow path of component K6 to the supply port 7 is blocked. In the illustration of Figure 3, the supply switching valve 11 is in the first switching position, i.e., the component K6 supplied via the component supply port 10a can flow past the retracted valve body 12a and its retracted conical sealing surface 13a. On its further path, component K6 can flow via the supply channel 9a to the supply port 7 and from there into the mixing chamber.Simultaneously, the flow path of component K7 to the supply connection 7 is blocked. The valve body 12b, with its conical sealing surface 13b, seals the access to the supply channel 9b. Component K7, which is present at or flowing to the component supply connection 10a, can be routed directly to the return line K7 via a bypass. The bypass can be located outside the component switching block.

[0044] The design of the return section RL of the component switching block 5 is analogous to the previously described design of the supply section VL. The return section RL of the component switching block 5 has two return channels 9'a and 9'b, which are joined at the return connection 8. A first return channel 9'a is for the return of one component, and a second return channel 9'b is for the return of the other component. In this example, the return of component K6 occurs via return channel 9'a, and the return of component K7 occurs via return channel 9'b. The return channels 9'a and 9'b are separated from each other by a return switching valve 11'. The design and operation of the return switching valve 11' correspond to the operation of the supply switching valve 11. Therefore, a further description of the design and operation of the return switching valve 11' is unnecessary here.The switching position of the return switching valve 11' is identical to the switching position of the supply switching valve 11. This means that component K6 can flow to the mixing chamber via the supply channel 9a and the supply connection 7, and that, when flowing back from the mixing chamber, component K6 can enter the component switching block 5 via the return connection 8. From there, the returning component K6 can flow via the return channel 9'a through the return switching valve 11', which is open in this switching position, into the return line of component K6.

[0045] Figures 3 and 4 each show an embodiment of a mixing head in which the component switching block 5 is attached directly to the head section 19 of the mixing head. Two injection nozzles 20 and 21 are installed in the head section 19, each having a nozzle housing 22, a nozzle needle 23 slidably therein, and a nozzle opening 24. A control piston 25 is slidably mounted in a corresponding bore in the head section 19 (see 77774-WO-KMT / Wl-Wl 15.01.2026 double arrow in Figure 3). In Figure 3, the control piston 25 is in a forward position. The control piston 25 is located within the mixing chamber (not shown here) and its front end connects to the outlet chamber 28. In Figure 4, the mixing chamber 26 is indicated by a spirally outlined rectangle. In both figures, the mixing head is shown in a recirculation state.The components flow back to their storage containers via recirculation grooves 27. When the control piston 25 is retracted, the mixing chamber 26 is released, and the components can flow into the mixing chamber 26 via the injection nozzles 20 and 21 and mix. The mixture is discharged via a discharge chamber 28. The discharge chamber 28 is cylindrical and extends downwards perpendicular to the plane of the drawing (in the direction behind the sectional view). A cleaning piston (not shown here) is movable within the discharge chamber 28, i.e., it moves perpendicular to the plane of the drawing.

[0046] Figure 3 shows a switching position of the component switching block 5 in which component K6 can flow towards the injection nozzle 21. Both the supply switching valve 11 and the return switching valve 11' are in a switching position such that only component K6 can flow to the injection nozzle 21. For this purpose, the hydraulic cylinders 15 and 15' are pressurized via the hydraulic connections 18a and 18'a. The flow path of component K6 is shown with solid arrows. The flow paths of component K7 are blocked. The flow paths of component K7 are shown with dotted arrows. Component K7 circulates via an associated bypass, not shown here. There is no flow in the supply channel 9b and the return channel 9'b of component K7.

[0047] Figure 4 shows a switching position of the component switching block 5 in which component K7 can flow towards the injection nozzle 21. Both the supply switching valve 11 and the return switching valve 11' are in a switching position such that only component K7 can flow to the injection nozzle 21 (see arrows with dotted lines). For this purpose, the hydraulic cylinders 15 and 15' are pressurized via the hydraulic connections 18b and 18'b. The flow paths of component K6 are blocked. Component K6 circulates via an associated bypass, not shown here. There is no flow in the supply channel 9a and the return channel 9'a of component K6.

[0048] Figure 5 shows an embodiment of a component feed switching device with a switching valve block 29 for components K8, K9, and K10. The switching valve block is shown in a very schematic and simplified manner. It comprises three inputs 30a, 30b, and 30c for the three components K8, K9, and K10 and an output 31 connected to the injection nozzle 20. This output 31 forms the outlet of the component switching device. A check valve 32a, 32b, and 32c is provided for each component, which is fluid-connected to the output 31 of the switching valve block 29 via a manifold 33. The desired component can be activated or deactivated.The component is activated and connected to the component supply line by building up pressure in the supply line 34a, 34b or 34c assigned to this component, which opens the associated check valve and thus allows the selected and activated component to flow through the switching valve block 29 to the injection nozzle 20. 77774-WO-KMT / Wl-Wl 15.01.2026.

[0049] Reference symbol

[0050] 1 cleaning piston hydraulic cylinder

[0051] 1A Hydraulic connection for rear end position

[0052] 1B Hydraulic connection for front end position

[0053] 2 control piston hydraulic cylinders

[0054] 2A Hydraulic connection for closed position

[0055] 2B Hydraulic connection for open position

[0056] 3, 4 hydraulic connections for injection nozzles

[0057] 5-component switching block

[0058] 5A, 5B Hydraulic connections for component switching

[0059] 7 Flow connection

[0060] 8 Return connection

[0061] 9a Supply channel for first component

[0062] 9b Supply channel for second component

[0063] 9'a Return channel for first component

[0064] 9'b Return channel for second component

[0065] 10a Component pre-connection for first component

[0066] 10b Component pre-connection for second component

[0067] 11 Flow control valve

[0068] 11' Return switching valve

[0069] 12a First valve body (First component)

[0070] 12b Second valve body (Second component)

[0071] 13a Sealing surface on the first valve body 12a

[0072] 13b Sealing surface on the second valve body 12b

[0073] 14 Piston rod

[0074] 15 hydraulic cylinders in the flow section VL

[0075] 15' Hydraulic cylinder in the return section RL

[0076] 16 hydraulic pistons in the flow section VL

[0077] 17 Preload spring in the leading section VL

[0078] 18a, b Hydraulic connections on hydraulic cylinder 15 in the flow section VL 18'a, b Hydraulic connections on hydraulic cylinder 15' in the return section RL 19 Head section of a mixing head

[0079] 20, 21 injection nozzles

[0080] 22 Nozzle housing / nozzle cartridge / nozzle needle guide 77774-WO-KMT / Wl-Wl 15.01.2026

[0081] 23 jet needle

[0082] 24 nozzle openings

[0083] 25 control pistons

[0084] 26 Mixing chamber

[0085] 27 recirculation grooves

[0086] 28 Outlet chamber

[0087] 29 Diverter valve block

[0088] 30a, b, c Inputs on the changeover valve block

[0089] 31 Output on the changeover valve block

[0090] 32a, b, c Check valves

[0091] 33 Collection line

[0092] 34a, b, c Supply lines for components K8, K9, K10 VL Supply section

[0093] RL return section

Claims

1. 77774-WO-KMT / Wl-Wl 15.01.2026 Claims 1. Mixing head for processing several components (K1, K2, K3, ... ) into a mixture, in particular a mixture of a reactive plastic, and for discharging the mixture, comprising a mixing chamber and several injection channels connected to the mixing chamber, wherein one of the components can be introduced into the mixing chamber via one of the injection channels, characterized by the fact that at least one of two or more components through which a component supply switching device (5) is provided, that the component supply switching device (5) has an outlet as a supply connection which is fluidly connected or connectable to an injection channel, and that the component supply switching device is designed so that a component can be selected which can be supplied to the supply connection.

2. Mixing head according to claim 1 , characterized by the fact that A component switching block (5) through which flow can be passed by two components is provided as a component supply switching device, the component switching block (5) comprising a supply section (VL) with two supply channels (9a, 9b), namely a first supply channel (9a) for a first component and a second supply channel (9b) for a second component, the two supply channels (9a, 9b) being joined at a supply connection (7) of the supply section (VL), a supply switching valve (11) being provided with which the flow path to the supply connection (7) can be selectively opened for one of the two components, and a fluid connection being provided between the supply connection (7) and one of the injection channels bypassing the component arriving at the supply connection (7) to the injection channel connected to this supply connection (7). 77774-WO-KMT / Wl-Wl 15.01.2026 3. Mixing head according to one of the preceding claims, characterized by the fact that The flow control valve (11) is designed as a double seat valve with two switching positions, namely a first switching position in which the first component can flow to the flow connection (7) and at the same time the flow path of the second component to the flow connection (7) is blocked, and a second switching position in which the second component can flow to the flow connection (7) and at the same time the flow path of the first component to the flow connection (7) is blocked.

4. Mixing head according to one of the preceding claims, characterized by the fact that the flow path of the components from the outlet of the supply connection (7) via the injection channel assigned to the component supply switching block to the entry into the mixing chamber is less than 1200 mm, preferably less than 800 mm and most preferably less than 200 mm.

5. Mixing head according to one of the preceding claims, characterized by the fact that the supply connection (7) is directly connected to an injection channel connected to the mixing chamber.

6. Mixing head for processing several components (K1, K2, K3, ...) into a mixture, in particular a mixture of a reactive plastic, and for discharging the mixture, comprising a mixing chamber and several injection channels connected to the mixing chamber, wherein one of the components can be introduced into the mixing chamber via each of the injection channels, and with one or more recirculation devices, in particular recirculation grooves or recirculation channels, which can be fluidly connected to component returns. characterized by the fact that at least one component return switching device (5) through which flow is provided, and that the component return switching device is designed such that switching between the component returns is possible in such a way that a selected component return is fluidly connected to a recirculation device.

7. Mixing head according to claim 6, characterized by the fact that A component switching block (5) through which flow can be passed by two components is provided as a component return switching device, the component switching block (5) comprising a return section (RL) with two return channels (9'a, 9'b), namely a first return channel (9'a) for a first component and a second return channel (9'b) for a second component, the two return channels (9'a, 9'b) being joined at a return port (8) of the return section (RL), and a return switching valve (11') being provided with which the flow path of the component flowing back from the recirculation device to the component switching block (5) can be released from the return port (8) into the return channel (9'a, 9'b) assigned to this component.

8. Mixing head according to claim 6 or 7, characterized by the fact that that the return switching valve (11') is designed as a double-seat valve with two switching positions, namely a first switching position in which the first component can flow from the return port (8) via the first return channel (9'a) to the return line of the first component and simultaneously the flow path of the second component from the return port (8) via the second return channel (9'b) to the return line of the second component is blocked, and a second switching position in which the second component can flow from the return port (8) via the second return channel (9'b) to the return line of the second component and simultaneously the flow path of the first component from the return port (8) via the first return channel (9'a) to the return line of the first component is blocked. 77774-WO-KMT / Wl-Wl 15.01.2026 9. Mixing head according to claim 1 and claim 6.

10. Mixing head according to one of the preceding claims, comprising at least one flow switching valve in the component flow switching device and at least one return switching valve in the component return switching device, characterized by the fact that the flow control valve (11) is designed as a double seat valve or as a double slide valve or as a combined slide-seat valve and / or that the return control valve (11') is designed as a double seat valve or as a double slide valve or as a combined slide-seat valve, wherein the double seat valve is preferably designed as a double needle seat valve, double cone seat valve, double ball seat valve or double disc seat valve.

11. Mixing head according to one of the preceding claims, characterized by the fact that a first drive for actuating a flow control valve (11) and a second drive for actuating a return control valve (1T) are provided, wherein the two drives are preferably each designed as a hydraulic drive (14, 15, 16).

12. Mixing head according to claim 11 , characterized by the fact that a hydraulic actuator is provided for the flow control valve (11) and for the return control valve (11'), and that the two hydraulic actuators can be operated simultaneously via a common hydraulic valve, such that the flow control valve (11) and the return control valve (1T) are operated simultaneously, in particular brought into the same switching position.

13. Mixing head according to claim 11 , characterized by the fact that The two drives can be operated independently of each other. 77774-WO-KMT / Wl-Wl 15.01.2026 14. Mixing head according to one of the preceding claims, characterized by the fact that a component supply switching device and a component return switching device are combined in a one-piece component switching block (5), such that a supply part (VL) and a return part (RL) are connected to form a block or combined in a block, and that this block is provided on the mixing head, wherein the block is preferably attached to the mixing head such that the supply connection of the supply part (VL) and / or the return connection of the return part (RL) are directly docked to an injection channel.

15. Mixing head according to one of the preceding claims, wherein the mixing head is designed as a high-pressure mixing head, comprising a mixing chamber in which a control piston is movable between at least two positions, namely a first position as a discharge position in which the mixture can be discharged from the mixing chamber into the molding tool, and a second position as a recirculation position in which the supply of components to the mixing chamber is interrupted and the components flowing to the mixing chamber can flow back into their associated storage containers.

16. Mixing head according to one of claims 1 to 14, wherein the mixing head is designed as a low-pressure mixing head, comprising a mixing chamber in which means for mixing the components are provided, in particular a rotating stirrer.

17. Mixing head according to claim 1 , characterized by the fact that The component feed-in switching device is designed as a switching valve block, wherein the switching valve block has a number of inlets corresponding to the number of components and an output which forms the outlet of the component feed-in switching device, wherein the switching valve block has a check valve for each of the components which is fluidly connected to the outlet of the switching valve block, and wherein a selected component can be activated which can flow to the outlet of the switching valve block via the check valve assigned to this component.

18. Mixing head according to one of the preceding claims, characterized by the fact that one or more of the injection channels are designed as injection nozzles.

19. Mixing head according to claim 18, characterized by the fact that A pressure compensation device is provided for at least one of the injection nozzles to compensate for changes in viscosity or quantity, in particular a spring-loaded nozzle needle or one pre-tensioned with compressed air. Jet needle.

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