Multi-way valve units for plastic melts and other medium to high viscosity fluids

Abstract

The invention relates to a multi-way valve unit (100) for medium-viscosity to high-viscosity fluids, the multi-way valve assembly having a housing, the housing comprising at least one of the following: an inlet plate having at least one main flow channel (41); an outlet plate having at least one main flow channel; and at least one secondary flow channel (42); wherein at least one intermediate plate (13, 14) and / or at least one spacing element (15) are located between the inlet plate and the outlet plate. The multi-way valve unit also has at least one switching element (20) pivotably or rotatably mounted in the housing (10), the switching element: being located between the inlet plate and the outlet plate; in a starting position, it connects the main flow channels (41) to each other via at least one through-opening (22, 23); and in at least one switching position, it connects at least one main flow channel (41) to at least one secondary flow channel (42) via at least one deflection channel (24), which leads only to one side of the switching element (20); wherein The switching element (20) is segmented and adjacent to the intermediate plates (13, 14) and / or at least one spacing element (15); the mouth opening of the main flow channel (41), which is arranged in the inlet plate (11) and / or the outlet plate (12) and faces the switching element (20), and the mouth opening of at least one secondary flow channel (42) are located on different pitch circles (1, 2) relative to the pivot axis (19) of the switching element (20); and the deflection channel (24) extends between the pitch circles (1, 2) on the switching element (20).

Description

Technical Field

[0001] The present invention relates to a multi-way valve unit for plastic melts and other medium to high viscosity fluids. Background Art

[0002] A multi-way valve unit is known from DE 100 30 584 A1. At least one switching element, rotatably mounted between two housing plates, switches reliably even at the high pressures and temperatures typical of plastic melts. One embodiment with the switching element is configured as a 3 / 2 valve and makes it possible to selectively direct the main flow from the inlet port to one of the two outlet ports. Two switching elements in the form of disks form a 4 / 7 valve, which allows a wide range of switching between a total of four connections. In this way, two independent circuits can operate adjacent to each other and form an alternating transmission between them. Since the switching elements are designed as disks, a correspondingly large housing is required, resulting in a large installation space required to accommodate the multi-way valve unit. Furthermore, at the moment of switching, the flow of the fluid is interrupted by the rotation of at least one switching element, which leads to problems caused by pressure peaks in the upstream and downstream production equipment.

[0003] WO 2003 090 998 A1 describes a simple filter device in which a screen holder with two screen elements can be rotated to allow one screen element at a time to be introduced into the production process. The production process is interrupted during the switchover between the two screen positions. There is no description or even possibility of using this device as a switching valve without a filtering function, as two branch lines cannot be connected on the output side, and no switching options are provided on the movable screen holder.

[0004] WO 2003 090 997 A1 shows another screen changing device in which one of two screens arranged on a segmented support can be brought into or out of the production process by rotating the support. The possibility of switching via a secondary flow channel or the like is not disclosed.

[0005] DE 10 2009 014 029 B4 describes a switching valve that achieves the goal of not interrupting the production process even during the switchover from one output line to another. However, its construction differs significantly from conventional multi-way valve units, as it is based on a cylindrical bolt that is axially displaceable within a bore in the housing. Achieving a leak-free connection requires significant manufacturing effort to precisely calibrate the fit between the bolt and the inner bore. For example, post-processing involving material removal is not possible. Summary of the Invention

[0006] The object of the present invention is therefore to create a multi-way valve unit which is suitable for plastic melts and fluids with similarly high viscosities, allows the fluid to be transferred from one main flow channel to at least one secondary flow channel, requires less space and is easier to produce and later handle than in the case of switching valves with cylindrical screws.

[0007] This object is achieved by the plastic melt multi-way valve unit of the present invention.

[0008] According to the invention, the switching element is first designed in the form of a segment, in particular a circular segment. Mounting is not done directly at the edge, but rather with the pivot axis offset toward the center of the segment. In this design, the narrow side of the segment acts as a control cam, where the connection to the drive is established, for example, in particular by the linear action of a hydraulic cylinder.

[0009] The flow-through groove is arranged in another part of the segment, and the pivot is located between the two. Since the flow-through groove is arranged on a circular segment, especially a size of 1 / 6 to 1 / 8 of the full circle, the required installation space is much smaller than that of the known multi-way valve having at least a disk as a switching element.

[0010] Furthermore, the present invention provides a configuration in which the grooves through which the flow of the primary and secondary flow channels can pass are arranged to be radially separated from each other or to extend between two different pitch circles. Thus, the pressure-bearing area is reduced to a narrow area adjacent to a single radius line, and a good seal is achieved.

[0011] The construction of the housing is similar to that of a rotary screen filter, i.e. the movable switching element is mounted between an inlet plate and an outlet plate, wherein the inlet plate and the outlet plate are kept at a certain distance from one another by means of interposed intermediate plates and / or other spacing elements, in such a way that in each case there is a minimum gap between the switching element and the inlet plate and the outlet plate, which gap allows the switching element to move but prevents the outflow of fluids with a moderately high viscosity.

[0012] The pressurized area should lie within a polygon which is delimited by a plurality of clamping elements which screw the housing panels together and, insofar as the movable switching element is concerned, preload them against one another.

[0013] A preferred embodiment provides only three clamping bolts or clamping screws, which define a prestressing triangle in which the flow-through groove is arranged.

[0014] It is further preferred that one of the clamping bolts or the clamping screw simultaneously forms the axis about which the switching element can be rotated.

[0015] A return channel is a groove extending inward from the segmented surface, but does not completely penetrate the segmented disc. The edge can be perpendicular to the surface, like a groove, or it can be rounded or beveled. The return channel directs flow from one side of the switch element from one flow channel to the other, but does not allow it to pass through.

[0016] In order to allow uninterrupted operation of the main channel during the switching process, it is advantageous to provide that the size, shape and position of the radially inner through-opening and the return flow channel in the switching element are selected relative to the size and position of the main channel terminal opening in the inlet plate and / or outlet plate so that the terminal opening and the through-opening continuously overlap during the rotation of the switching element. Consequently, the main channel is not closed and can operate uninterrupted.

[0017] For the purposes of the present invention, "non-closing" or "uninterrupted" means in particular that in any operating state of the multi-way valve unit, the cross-section of the flow channel is not restricted so strongly that more than 80% of the cross-sectional area of the individual flow channels in the multi-way valve unit is covered by the switching element and / or that a sharp pressure increase occurs during the switching process due to the change in the cross-section in the flow channel.

[0018] For uninterrupted operation, a bridging web narrower than the diameter of the end opening of the main channel is formed on the switching element, in particular between the radially inner through-opening and the return channel.

[0019] In another embodiment, it is possible to operate continuously in two independent circuits or to switch continuously between them. To this end, the size, shape, and position of the radially outer through-opening and the return flow channel of the switching element are selected relative to the size and position of the terminal openings of the secondary flow channel on the inlet plate and / or outlet plate so that the terminal openings continuously overlap with the through-opening or the return flow channel or both during rotation of the switching element.

[0020] Furthermore, the diameter of the outer through-opening can be selected to be significantly larger than the diameter of the inner through-opening, and the groove on one side between them can be shaped accordingly. This applies in particular to the tangential extension of the through-opening or its extension along the respective pitch arc.

[0021] Since the opening cross sections are located in each case on the same pitch circle, a small pivot angle of the switching element is sufficient for switching, wherein the opening cross sections on the inner pitch circle and the opening cross sections on the outer pitch circle simultaneously overlap.

[0022] The openings on the inner and outer pitch circles can be provided with circular cross sections. For this reason, it is necessary to design the segment-shaped switching element to be longer so that its overall size is increased.

[0023] It is therefore particularly preferred that the outer through-openings and / or the outer portion of the return channel are designed in a rectangular or arched manner and extend along the outer pitch circle. In this case, however, the radial extent of the openings on both pitch circles is approximately equal. This also allows for a continuous overlap of the cross sections during the transition, resulting in very compact dimensions.

[0024] In a preferred embodiment, the primary and secondary flow channels in the housing plate each have a circular cross section, as these are easy to manufacture. However, oval or rectangular cross sections in the housing are also possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be described in detail below with reference to an exemplary embodiment of a multi-way valve unit shown in the drawings, which is designed as a 4 / 2 valve. Specifically, these drawings show:

[0026] Figure 1 is a perspective view of the multi-way valve unit at a certain angle from the front;

[0027] Figure 2 It is a perspective view of the multi-way valve unit at a certain angle from the rear;

[0028] Figures 3A to 3C 1 and 2. Various positions of the multi-way valve unit 100 according to the first embodiment;

[0029] Figure 4 is a schematic cross-sectional view of the multi-way valve unit in an initial position;

[0030] Figure 5 is a schematic cross-sectional view of a multi-way valve unit in a switching position;

[0031] Figures 6A to 6B is a schematic cross-sectional view of a multi-way valve unit according to a second embodiment;

[0032] 7A to 7C Various positions of the multi-way valve according to the third embodiment. DETAILED DESCRIPTION

[0033] Figure 1 A perspective view of a multi-way valve unit 100 is shown at an angle to the front. The valve comprises a housing 10, a switching element 20 pivotably mounted therein and a drive unit 30 for the switching element 20.

[0034] The housing 10 includes:

[0035] an inlet plate 11 having a primary flow channel 41 terminating in an inlet-side terminal opening 11 . 1 , and a secondary flow channel 42 terminating in a terminal opening 11 . 2 ,

[0036] - a plurality of intermediate plates 13, 14 and spacer elements 15;

[0037] - An outlet plate 12 which in turn contains outlet openings and terminal openings for the primary and secondary flow channels.

[0038] The inlet plate 11 , the outlet plate 12 , the intermediate plates 13 , 14 and the spacer element 15 are connected to one another and preloaded against one another by means of three clamping bolts 17 , 18 , which extend straight through the entire plate stack.

[0039] The drive unit 30 is arranged on the top of the housing 10 and comprises two parallel beams 32, of which the front beam is shown in FIG. Figure 1 The hydraulic cylinder 31 forms the drive device. The hydraulic cylinder 31 is pivotally mounted between crossbeams 32 on an axis 34. The piston rod of the hydraulic cylinder 31 is connected to the cam 29 of the switching element 20 via a fork-shaped element 33.

[0040] Figure 2 A perspective view of a multi-way valve unit 100 is shown, angled from the rear and below, that is, from the outlet side. The outlet plate 12 is shown transparent here to allow visibility of the elements arranged between the inlet and outlet plates 11, 12: the fixed intermediate plates 13, 14 and the pivotally arranged switching element 20. The switching element 20 is mounted on the spacing element 15 via a hole; a sliding bearing is used between them. The arrangement and path of the three clamping bolts 17, 18 can also be seen. These bolts extend straight through the entire plate stack of the inlet plate 11, outlet plate 12, and intermediate plates 13, 14, including through the spacing element 15. In this design, the center of the top clamping bolt 18 also forms the pivot axis 19, about which the switching element 20 can be moved.

[0041] The switching element 20 is in the form of a circular segment. Most of its surface facing the inlet plate 11 or outlet plate 12 is embodied as a sealing surface 21. Grooves for guiding the fluid and spacer elements 15 serving as bearings are arranged within the sealing surface 21. A cam 29 extends from the top of the housing 10 and is connected to the drive unit.

[0042] The main flow channel 43 extends through the outlet plate 12 to the outlet terminal opening 12.1. A curved secondary flow channel 44 also extends within the outlet plate 12, terminating at the outlet terminal opening 12.2 arranged in the side surface of the outlet plate 12.

[0043] The task of the intermediate plates 13 , 14 and the spacer elements 15 is to position the inlet plate 11 and the outlet plate 12 at a constant, precisely defined distance from one another. In addition, the intermediate plates 13 , 14 can serve as fixed stops to limit the movement of the switching element 20 .

[0044] In this design, the thickness of the intermediate plates 13, 14 or the spacer element 15 and the thickness of the switching element 20 must be matched to one another, so that the intermediate plates 13, 14 and the spacer element 15 are slightly oversized, thereby forming a minimum gap between the sealing surface 21 of the switching element 20 and the adjacent surfaces of the inlet and outlet plates 11, 12. This gap allows the switching element 20 to move relative to the inlet and outlet plates 11, 12, but on the other hand, it is so small that a medium with a medium to high viscosity (e.g., a plastic melt) can only enter this gap to a very small extent without flowing out of the housing 10 in the process. In this case, the fluid that enters the gap effectively acts as a lubricant for the movable switching element 20. Therefore, in the multi-way valve unit 100 according to the present invention, the necessary sealing effect can only be achieved in combination with the use of a suitable medium- to high-viscosity medium, particularly a plastic melt. Consequently, the multi-way valve unit 100 according to the present invention is not suitable for dispensing gases and low-viscosity fluids such as water.

[0045] The main flow channel formed in the multi-way valve unit 100 is connected from the inlet side terminal opening 11.1 (see Figure 1 ) extends in a straight line through the corresponding through-opening in the switching element 20 and through the main channel 43 to the outlet-side terminal opening 12.1. The secondary channel 44 in the outlet plate 12 extends from the internal contact plane with the switching element 20 to the lateral terminal opening 12.2.

[0046] In the sealing surface 21 of the switching element 20 facing the outlet plate 12 , a recess is introduced as a return flow channel 25 , via which a flow connection can be produced between the primary flow channel 43 and the secondary flow channel 44 .

[0047] The arrangement of the terminal openings 11.2, 12.2 of the secondary channels 42, 44 on one side of the corresponding inlet plate 11 or outlet plate 12 has the advantage that the multi-way valve unit 100 can be directly inserted into the production line via the main channels 41, 43 opening on both end faces and can be connected to upstream or downstream production equipment, wherein there are no obstacles to the connection to the secondary channels 42, 44.

[0048] The exemplary embodiment of the multi-way valve unit 100 therefore comprises four connections to the end openings 11 . 1 , 11 . 2 , 12 . 1 , 12 . 2 and provides two different operating positions of the switching element, so that it is a 4 / 2 valve.

[0049] Figures 3A to 3C Various positions of the multiway valve unit 100 during switching are shown, for which purpose only the elements arranged between the inlet plate 11 and the outlet plate 12 are shown in each case, in particular the switching element 20 in a front view facing the inlet plate.

[0050] The switching element 20 is pivotally mounted on the pivot axis 19 formed by the spacer element 15. The latter is annular. The outer circumference serves as a sliding bearing surface, while the inner circumference accommodates the clamping screw 18. The dashed circles indicate the location of the primary flow channel 41 and the secondary flow channel 42. The switching element 20 has two through-openings 22 and 23, which are designed as circular holes and extend completely through the switching element 20. Another groove is designed in the form of a return flow channel 24, which is located on the front side of the switching element 20 facing the inlet plate.

[0051] Figure 3A The illustrated position of the switching element 20 corresponds to the initial position of the multi-way valve unit 100, wherein the respective primary channels 41, 43 in the inlet plate 11 and the outlet plate 12 are connected via the through-opening 22 in the switching element 20, while the respective secondary channels 42, 44 are connected via the through-opening 23. It can also be seen here that the clamping bolts 17, 18 define a triangle within which the flow path formed by the primary channel 41 and the secondary channel 42 lies. This serves to increase the tightness of the seal, as the gap width between the inlet plate 11 and the outlet plate 12 of the housing 10 and the switching element 20 can be adjusted, as pressurization of the flowing fluid can be counteracted by a corresponding preload at the clamping bolts 17, 18, thereby preventing excessive widening.

[0052] Figure 3B shows an intermediate position in the conversion process. Figure 3A In comparison, the switching element has been pivoted clockwise by approximately 30°.

[0053] In order to allow uninterrupted operation in the primary channel 41 even during the switching process, this channel is arranged radially closer to the pivot bearing or pivot axis 19 of the switching element 20 than the secondary channel 42. In addition, a bridging web 26 is formed between the through-opening 22 of the primary channel 41 and the return channel 24. At a reference line about the pivot axis 19, which passes through the center point of the radially inner region of the through-opening 22 and the return channel 24, the bridging web 26 is narrower than the diameter of the through-opening 22 and narrower than the preferably equally large cross-sectional opening of the primary channel 41.

[0054] exist Figure 3B In the middle position, the main flow channel 41 overlaps with the through opening 22 of the switching element 20 and the radially inner area of the return flow channel 24. In this way, some fluid can still continue to flow through the main flow channels 41, 43, while a connection with the secondary flow channel 42 already exists through the return flow channel 24.

[0055] exist Figure 3C, the switching position is shown, in which the switching element 20 separates the primary flow channels 41, 43 and the secondary flow channels 42, 44 on the inlet plate 11 and the outlet plate 12 from one another. Conversely, the primary flow channel 41 is connected to the secondary flow channel 42 on the inlet plate 11 via the return channel 24. The same situation occurs on the far side of the switching element 20 at the outlet plate.

[0056] Two possible operating positions of the multi-way valve unit 100 are shown in FIG. Figure 4 and 5 , in each case a schematic cross-sectional side view is shown. Each arrow indicates a possible flow direction.

[0057] exist Figure 4 In the figure, the corresponding Figure 3A The flow path configuration for the position of switching element 20 corresponds to the initial position during normal operation of multi-way valve unit 100. Fluid enters primary channel 41 on inlet plate 11 through inlet-side terminal opening 11.1, flows through through-opening 22 in switching element 20 into primary channel 43 on outlet plate 12, and exits again at outlet-side terminal opening 12.1. Simultaneously, fluid enters secondary channel 44 from terminal opening 12.2 on outlet plate 12, passes through through-opening 23 into secondary channel 42 in inlet plate 11, and exits at terminal opening 11.2, creating a flow connection in the opposite direction.

[0058] exist Figure 5 In the switching position, the multi-way valve unit 100 is in the switching position. A connection now exists between the main flow channel 41 and the secondary flow channel 42 in the inlet plate 11, and between the main flow channel 43 and the secondary flow channel 44 in the outlet plate 12, in each case via a return flow channel 24, 25 on the switching element 20. Figure 4 and Figure 5 The configuration in [ ] uses switching without reverse traffic direction.

[0059] Figure 6A and Figure 6B The cross-sectional views of another embodiment of the multi-way valve unit 100" in the switching position are schematically shown. The initial position (not shown) of the multi-way valve unit 100" is Figure 4 , that is, in the initial position, there is a connection between the main flow channel 41 and the secondary flow channel 42 in the inlet plate 11 and between the flow channels 43, 44 in the outlet plate 12, in each case via one of the through-openings in the switching element 20". In other words, there is a continuous main flow channel and a continuous secondary flow channel.

[0060] During the switching process, the main flow channel remains open; however, an additional flow connection is created between the main flow channel and a portion of the secondary flow channel. To this end, the switching element 20" is provided with a return flow channel 24" on one side. This channel comprises a groove extending radially on one side of the switching element 20" and terminates in a through-opening, thus forming an L-shaped structure in cross section. The secondary flow channel 44 is closed, and the secondary flow channel 42 feeds from the main flow channels 41 and 43, with the flow direction remaining unchanged.

[0061] In this embodiment, a further return channel 25" can be provided at a third angular position on the segmented switching element 20". The return channel 25" also consists of a through-opening and a single-sided groove on the other side of the switching element 20", so that the secondary flow channel 44 in the outlet plate 12 can be connected to the main flow channel 43. In this case, for example, the flow direction is reversed, so that this position is suitable for backflushing the secondary flow channel.

[0062] 7A to 7C Shown in a similar Figures 3A to 3C A further embodiment of a multi-way valve unit 100' with a switching element 20' is provided in the position of the switch. Its segmented shape, mounting on the clamping bolt 18, and the position and size of the through-opening 22 are identical to those of the first embodiment. The difference lies in the shape of the through-opening 23', located radially outside the through-opening 22 and designed as a rectangular hole or an arc-shaped slot. This is also the through-opening in the switching element 20'.

[0063] exist Figure 7A In the initial position, the two main flow channels 41 and 43 of the inlet plate 11 and the outlet plate 12 are connected to each other through the through-opening 22. At the same time, the secondary flow channels 42 and 44 in the inlet plate 11 and the outlet plate 12 are connected to each other through the through-opening 23'. The portion of the cross-sectional area of the through-opening 23' that is not directly aligned with the secondary flow channels 42 and 44 is also pressurized. This portion remains within the area pre-stressed by the clamping bolts 17 and 18.

[0064] exist Figure 7B In a similar way Figure 3B ' shows an intermediate position between two operating states of the multi-way valve unit 100 according to the present invention. It can be seen here that the through-opening 22 and the return channel 24 are connected to each other by a terminal opening on the side radially close to the axis. At the same time, in this intermediate position, a flow connection also exists between the outer area of the return channel 24, the secondary channel 42 and the rectangular through-opening 23'. Due to the improved switching element 20', in this embodiment of the multi-way valve unit 100', all flow channels can be operated continuously, that is, during the switching process, the main channels 41, 43 and the secondary channels 42, 44 are not completely closed.

[0065] exist Figure 7CIn the switching position, the switching position is reached again, in which the main flow channel 41 and the secondary flow channel 42 in the inlet plate 11 and the main flow channel 43 and the secondary flow channel 44 in the outlet plate 12 are connected together in pairs through the return channels 24 and 25.

[0066] Reference numerals:

[0067] 100, 100', 100" multi-way valve unit

[0068] 1st and 2nd pitch circles

[0069] 10 Housing

[0070] 11 entrance panel

[0071] 11.1, 11.2 Terminal openings

[0072] 12 outlet plates

[0073] 12.1, 12.2 Terminal openings

[0074] 13, 14 middle plate

[0075] 15 spacer elements

[0076] 17, 18 clamping elements

[0077] 19 pivot axis

[0078] 20, 20', 20" switch elements

[0079] 21 Sealing surface

[0080] 22, 23, 23', 22" through openings

[0081] 24, 25, 24", 25" return channel

[0082] 26 Bridging web

[0083] 29 Cam

[0084] 30 drive units

[0085] 31 hydraulic cylinder

[0086] 32 beam

[0087] 33 Fork element

[0088] 34 axis

[0089] 41, 43 main channel

[0090] 42, 44 secondary flow channel

Claims

1. A multi-way valve unit (100, 100', 100") for plastic melts and medium- to high-viscosity fluids, the multi-way valve unit having a housing (10) comprising at least: - an inlet plate (11) having at least one main flow channel (41); - an outlet plate (12) having at least one main flow channel (43), and - at least one secondary flow channel (42, 44); wherein at least one intermediate plate (13, 14) and / or at least one spacer element (15) is arranged between the inlet plate (11) and the outlet plate (12), The multi-way valve unit has at least one switching element (20, 20', 20"), which is pivotally or rotatably mounted in a housing (10), and the switching element: - arranged between the inlet plate (11) and the outlet plate (12), - in the initial position, the main channels (41, 43) are connected to each other via at least one through-opening (22, 23, 23', 22"), and - in at least one switching position, connecting at least one main flow channel (41, 43) to at least one secondary flow channel (42, 44) via at least one return flow channel (24, 25, 24", 25") which is open only on one side of the switching element (20, 20', 20"), It is characterized by - the switching element (20, 20', 20") is designed in the form of a segment and is arranged adjacent to the intermediate plate (13, 14) and / or at least one spacing element (15), - a terminal opening of a main channel (41, 43) present in the inlet plate (11) and / or the outlet plate (12) and facing the switching element (20, 20', 20"), and a terminal opening of at least one secondary channel (42, 44), the terminal openings of the main channel (41, 43) and the terminal openings of the secondary channel (42, 44) being arranged at different pitch circles (1, 2) relative to the pivot axis (19) of the switching element (20, 20', 20"), and The return flow channels (24, 25, 24", 25") on the switching elements (20, 20', 20") extend between the pitch circles (1, 2).

2. The multi-way valve unit (100, 100', 100") according to claim 1, characterized in that The inlet plate (11) and the outlet plate (12) each have a main flow channel (41, 43) and a secondary flow channel (42, 44).

3. The multi-way valve unit (100, 100', 100") according to claim 2, characterized in that The switching element (20, 20', 20") has a return flow channel (24, 25, 24", 25") on each of its two sides.

4. The multi-way valve unit (100, 100', 100") according to claim 2 or 3, characterized in that The switching element (20, 20', 20") has a through opening (22, 23, 22") on each of the two pitch circles (1, 2).

5. The multi-way valve unit (100") according to claim 2 or 3, characterized in that: A switching element (20") for producing a flow connection between an open primary flow channel and at least a section of a secondary flow channel (42, 44) comprises at least one return flow channel (24", 25") which extends between the pitch circles (1, 2) and is connected to one of the through openings (22, 23, 23', 22").

6. The multi-way valve unit (100, 100', 100") according to claim 1, characterized in that The size, shape and position of the radially inner through-opening (22) and the return channel (24, 25, 24", 25") on the switching element (20, 20', 20") are selected according to the size and position of the terminal opening of the main channel (41, 43) in the inlet plate (11) and / or the outlet plate (12), so that the terminal opening continuously overlaps with the through-opening (22) or with the return channel (24, 25, 24", 25") or with both the through-opening and the return channel during the pivoting of the switching element (20, 20', 20").

7. The multi-way valve unit (100, 100', 100") according to claim 6, characterized in that The terminal opening of the main flow channel (41, 43) on the switching element (20, 20', 20") and the related through opening (22) on the switching element (20, 20', 20") are arranged closer to the pivot axis (19) than the terminal opening of the at least one secondary flow channel (42, 44).

8. The multi-way valve unit (100, 100', 100") according to claim 6, characterized in that At least one bridging web (26) is formed on the switching element (20, 20', 20") between at least one through opening (22, 23) and the return channel (24, 25, 24", 25"), and the bridging web is narrower than the diameter of the terminal opening of the main channel (41, 43).

9. The multi-way valve unit (100, 100', 100") according to claim 4, characterized in that The through openings (22, 23) are located on the same radial line, and the longitudinal extent of the return flow channels (24, 25, 24", 25") is radially oriented between the pitch circles (1, 2).

10. The multi-way valve unit (100, 100', 100") according to claim 4, characterized in that The tangential extent of the through-opening (23) located on the outer pitch circle (2) is greater than the tangential extent of the inner through-opening (22).

11. The multi-way valve unit (100') according to claim 10, characterized in that: The outer through-opening (23') is designed to be oblong or arched and extends along the outer pitch circle (2).

12. The multi-way valve unit (100, 100', 100") according to claim 1, characterized in that The respective ends of a main flow channel (41) in an inlet plate (11) at the transition to a switching element (20, 20', 20") and a secondary flow channel (42) in an outlet plate (12) at the transition to a switching element (20, 20', 20") are arranged within a polygon, which is delimited by a plurality of clamping elements (17, 18) which pass through adjacent plates among the inlet plate, the outlet plate and the intermediate plate.

13. The multi-way valve unit (100, 100', 100") according to claim 12, characterized in that Three clamping elements (17, 18) are provided which define a triangle.

14. The multi-way valve unit (100, 100', 100") according to claim 1, characterized in that The return flow channel (24, 25, 24", 25") is formed by at least one groove or recess introduced into one side of the switching element (20, 20', 20").

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