COILS FOR DIRECTIONAL VALVE ASSEMBLIES AND METHOD FOR MANUFACTURING COILS

Abstract

A coil (120) defining a coil longitudinal axis (122), the coil (120) comprising:a first web module (130) defining a first web module circumferential surface (132);a second web module (140) defining a second web module circumferential surface (142); anda first dosing module (150), wherein:a first end cap (152) of the first dosing module (150) is coupled to the first web module (130); anda second end cap (154) of the first dosing module (150) is coupled to the second web module (140),characterized in thatthe first dosing module (150) defines a virtual central core region (180) of the first dosing module that is concentric with the coil longitudinal axis (122) and a virtual hollow cylinder region (182) of the first dosing module that surrounds the virtual central core region (180) of the first dosing module;andat least two columns (184) of the first dosing module (150) extend between the first end cap (152) of the first dosing module (150) and the second end cap (154) of the first dosing module (150), wherein the at least two columns (184) of the first dosing module (150) are arranged entirely within the virtual hollow cylinder region (182) of the first dosing module.;

Description

Technical area

[0001] The present disclosure relates to hydraulic valves used in heavy machinery used in the earthmoving, construction, and mining industries, or the like. More particularly, the present disclosure relates to a valve component, such as a spool, and methods of manufacturing spools. State of the art

[0002] Heavy machinery, such as that used in the earthmoving, construction, and mining industries, employs various hydraulically powered systems and implements to perform movements and tasks, such as moving payloads with buckets, crushing materials using a hydraulic breaker, lifting a boom, etc. These systems and implements include hydraulic valve assemblies for controlling the flow of hydraulic fluid. A spool valve assembly is a type of hydraulic valve assembly that includes a housing defining a spool cavity within which a spool is disposed. The spool typically includes land portions that slidably contact the spool cavity and metering portions that have one or more cavities to allow fluid flow therethrough.

[0003] U.S. Patent No. US 10,508,746 B2 (the "'746 patent"), issued on December 17, 2019, describes a directional control valve with a spool formed as a single monolithic component that includes both lands for blocking fluid flow and chambers for passing fluid flow. The spool of the '746 patent also has a solid core running the entire length of the spool. While the '746 patent may be advantageous, a better spool is desired.

[0004] DE 10 2016 220 855 A1 discloses a valve spool and a valve equipped therewith. The valve spool has a longitudinal axis and a shaft body with support sections and control units connected thereto. The support sections protrude radially from the shaft body and have a larger outer diameter. Further valve arrangements are known from FR 3 025 844 A1 and US 3 017 901 A. Brief description of the revelation

[0005] In one aspect of the present disclosure, a coil is disclosed according to claim 1, defining a coil longitudinal axis. The coil includes a first land module defining a first land module circumferential surface, a second land module defining a second land module circumferential surface, and a first metering module. The first metering module has a first end cap coupled to the first land module and a second end cap coupled to the second land module.According to the invention, it is provided that the first dosing module defines a virtual central core region of the first dosing module, which is concentric with the coil longitudinal axis, and a virtual hollow cylinder region of the first dosing module, which surrounds the virtual central core region of the first dosing module, wherein at least two columns of the first dosing module extend between the first end cap of the first dosing module and the second end cap of the first dosing module, wherein the at least two columns of the first dosing module are arranged completely within the virtual hollow cylinder region of the first dosing module.

[0006] In another aspect of the disclosure, a directional control valve assembly is disclosed according to claim 12. The directional control valve assembly includes a housing having a housing interior surface defining a spool cavity. The housing further defines a first port, a second port, and a third port, each of the first port, the second port, and the third port extending through the housing interior surface and being in fluid communication with the spool cavity. A spool according to the invention is disposed within the spool cavity and defines a spool longitudinal axis.The coil includes a first land module defining a first land module circumferential surface dimensioned for sliding contact with the housing interior surface, a second land module defining a second land module circumferential surface dimensioned for sliding contact with the housing interior surface, and preferably a third land module defining a third land module circumferential surface dimensioned for sliding contact with the housing interior surface. The coil further includes a first dosing module having a first end cap coupled to the first land module and preferably defining at least one dosing pocket, and a second end cap coupled to the second land module and preferably defining at least one dosing pocket.In addition, the coil preferably further includes a second dosing module having a first end cap coupled to the second web module and defining at least one dosing pocket, and a second end cap coupled to the third web module and defining at least one dosing pocket.

[0007] In yet another aspect of the disclosure, a method of manufacturing a coil for use with a housing according to claim 13 is disclosed, having a housing inner surface defining a coil cavity. The method includes forming a first land module having a first land module circumferential surface dimensioned for sliding contact with the housing inner surface, forming a second land module having a second land module circumferential surface dimensioned for sliding contact with the housing inner surface, and forming a first metering module having a first end cap and a second end cap by additive manufacturing. The method further includes coupling the first end cap of the first metering module to the first land module and coupling the second end cap of the first metering module to the second land module.The first web module, the first dosing module, and the second web module extend along a coil longitudinal axis. According to the invention, the method further comprises forming a third web module with a third web module circumferential surface dimensioned for sliding contact with the housing inner surface, forming a second dosing module with a first end cap and a second end cap by additive manufacturing, coupling the first end cap of the second dosing module to the second web module, and coupling the second end cap of the second dosing module to the third web module, wherein the second dosing module and the third web module extend along the coil longitudinal axis, the first dosing module defines a virtual central core region of the first dosing module that is concentric with the coil longitudinal axis, and a virtual hollow cylinder region of the first dosing module that surrounds the virtual central core region of the first dosing module.Forming the first dosing module by additive manufacturing further comprises forming at least two columns of the first dosing module that extend between the first end cap of the first dosing module and the second end cap of the first dosing module, wherein the at least two columns of the first dosing module are arranged entirely within the virtual hollow cylinder region of the first dosing module. Brief description of the drawings Fig. 1 is a perspective cross-sectional view of an exemplary directional control valve assembly incorporating a spool according to the present disclosure; Fig. 2 is an enlarged perspective view of the coil of Fig. 1. Fig. 3 is an exploded perspective view of the coil of Fig. 1. Fig. 4 is an enlarged perspective view of a first dosing module of the coil of Fig. 1-3. Fig. 5 is an end view of the first dosing module of the coil of Fig. 1-4. Fig. 6 is an end view of a second dosing module of the coil of Fig. 1-3. Fig. Figure 7 is a schematic view of a cross section of another embodiment of a column used in the coil of Fig. 1-3 can be used; and Fig. Figure 8 is a schematic block diagram of a method of forming a coil for use in a package. Detailed description

[0008] Reference will now be made in detail to specific embodiments or features, examples of which are illustrated in the accompanying drawings. In general, throughout the drawings, corresponding reference numerals are used to refer to like or corresponding parts unless otherwise indicated. Fig. 1 shows an example of a directional control valve assembly 100 incorporating the features of the present disclosure. The directional control valve assembly 100 may be provided as part of a hydraulic system, such as a steering system, a braking system, an implement control system, a pump control system, an engine system, or a fuel control system used on a machine such as a wheel loader, motor grader, work machine, or excavator.

[0009] Fig. 1 illustrates an exemplary directional control valve assembly 100 including a housing 102 with an interior housing surface 104 defining a spool cavity 106. In the illustrated embodiment, the housing further includes a first through-opening 108, a second through-opening 110, and a third through-opening 112. The first through-opening 108, the second through-opening 110, and the third through-opening 112 each extend through the interior housing surface 104 and are in fluid communication with the spool cavity 106. The first, second, and third through-openings 108, 110, 112 are in fluid communication with other cavities within the housing 102 and / or with components coupled to the housing 102 to thereby direct fluid flow through the housing 102.

[0010] The directional control valve assembly 100 also includes a spool 120 disposed within the spool cavity 106 for selectively establishing fluid communication between the first, second, and third passageways 108, 110, 112. The spool 120 defines a spool longitudinal axis 122 along which the spool 120 is translated during operation.

[0011] According to certain aspects of the present disclosure, the coil 120 is formed from multiple modules that are independently manufactured and subsequently assembled. As best described in Fig. 1-3, for example, the spool 120 includes a first land module 130 defining a first land module circumferential surface 132 dimensioned for sliding contact with the housing interior surface 104. The spool 120 further includes a second land module 140 spaced from the first land module 130 and defining a second land module circumferential surface 142 dimensioned for sliding contact with the housing interior surface 104. A first metering module 150 structurally couples the first land module 130 to the second land module 140. More specifically, the first metering module 150 includes a first end cap 152 coupled to the first land module 130 and a second end cap 154 ​​coupled to the second land module 140.

[0012] In some examples, the spool 120 includes more than two land modules and one metering module. In the illustrated example, the spool 120 further includes a first land module 160 defining a third land module peripheral surface 162 dimensioned for sliding contact with the housing interior surface 104. Additionally, the spool 120 may include a second metering module 170 structurally coupling the second land module 140 to the third land module 170. The second metering module 170 may include a first end cap 172 coupled to the second land module 140 and a third end cap 174 coupled to the second land module 140. In other examples, the spool 120 may include additional land modules and metering modules as required for a particular application.

[0013] After independent fabrication, the modules can be coupled together to form the coil 120. For example, each of the web modules 130, 140, and 160 can include externally threaded portions 177, and each of the metering modules 150, 170 can include internally threaded portions 179, so that the modules can be threadably coupled.

[0014] The first and second metering modules 150, 170 may be configured to improve the metering of fluid flow during operation of the directional control valve assembly 100. As best described in Fig. 2 and Fig. 3, the first end cap 152 and the second end cap 154 ​​of the first dosing module 150 each include at least one dosing pocket 156. Similarly, the first end cap 172 and the second end cap 174 of the second dosing module 170 each include at least one dosing pocket 176. In the illustrated embodiment, each end cap is shown with four dosing pockets 156 or 176 spaced circumferentially around the associated end cap, however, the exact number of dosing pockets on each end cap may be greater or less than four. While the dosing pockets 156, 176 are illustrated as crescent-shaped depressions, the dosing pockets 156, 176 may take other shapes. Furthermore, each end cap may be formed with a beveled surface 158 or 178, and each dosing pocket 156, 176 extends into a respective beveled surface 158, 178.

[0015] According to further aspects of the present disclosure, both the first dosing module 150 and the second dosing module 170 are constructed to have reduced weight and improved fluid flow therethrough while maintaining structural integrity. More specifically, instead of employing a conventional solid core, each of the first and second dosing modules 150, 170 includes discrete structural components, referred to herein as "pillars," located around the perimeter of the module. For example, as shown in Fig. As shown in Figures 2-5, the first dispensing module 150 defines a virtual first dispensing module central core region 180 concentric with the coil longitudinal axis 122 and a virtual first dispensing module hollow cylinder region 182 surrounding the virtual first dispensing module central core region 180. The first dispensing module 150 includes at least two columns 184 extending between the first end cap 152 of the first dispensing module 150 and the second end cap 154 ​​of the first dispensing module 150. The at least two columns 184 of the first dispensing module 150 are disposed entirely within the virtual hollow cylinder region 182 of the first dispensing module.

[0016] In a similar way as in Fig. 2, Fig. 3 and Fig. 6, the second dosing module 170 defines a virtual second dosing module central core region 190 concentric with the coil longitudinal axis 122 and a virtual second dosing module hollow cylinder region 192 surrounding the virtual second dosing module central core region 190. The second dosing module 170 includes at least two columns 194 extending between the first end cap 172 of the second dosing module 170 and the second end cap 174 of the second dosing module 170. The at least two columns 194 of the second dosing module 170 are disposed entirely within the virtual hollow cylinder region 192 of the second dosing module.

[0017] As used herein, "virtual" means having the attributes of an entity without possessing its physical form. A virtual core region is, for example, an intangible region or a reference region that can be defined relative to other physical and / or intangible entities. In the illustrated embodiments, the central core region 180 of the virtual first dosing module and the central core region 190 of the virtual second dosing module have cylindrical shapes, while the hollow cylinder region 182 of the virtual first dosing module and the hollow cylinder region 192 of the virtual second dosing module have hollow cylindrical shapes.

[0018] By locating the columns 184, 194 outside the central cores of the first and second dosing modules 150, 170, the spool 120 reduces the amount of turbulence produced as fluid flows through the first and second dosing modules 150, 170. Furthermore, by locating the columns 184, 194 closer to the peripheries of the first and second dosing modules 150, 170, weight is reduced while maintaining structural integrity.

[0019] The columns 184, 194 can be formed with different cross-sectional shapes. In the examples shown in Fig. 1-6, for example, each of the columns 184, 194 has a circular cross-section 200. Alternatively, as in Fig. 7, the columns 184, 194 may be formed with a non-circular cross-section 210. Furthermore, the non-circular cross-section 210 may have a major axis 212 and a minor axis 214. Without wishing to be bound by theory, it is believed that the non-circular cross-section 210 may further improve the flow characteristics of the fluid through the first and second dosing modules 150, 170. Furthermore, it is believed that the non-circular cross-section 210 may resist rotation of the coil 120 within the housing 102, causing the fluid flowing around the columns to generate forces that align the major axes 212 with the direction of fluid flow.

[0020] While the illustrated example includes first and second dosing modules 150, 170 that are identically configured, in other examples, the first dosing module 150 may have a different configuration than the second dosing module 170. That is, the number, placement, cross-sectional shape, and configuration of the columns 184 in the first dosing module 150 may differ from those of the columns 194 of the second dosing module 170. Additionally or alternatively, the first and second end caps 152, 154 of the first dosing module 150 may have a different overall configuration, number and shape of the dosing pockets 156, and the location and shape of the beveled surface 158 than the first and second end caps 172, 174 of the second dosing module 170.

[0021] It should be noted that each of these components and their features may be configured differently in other embodiments of the present disclosure. The components of the valve assembly may be constructed from any suitable material, including but not limited to steel, aluminum, thermoplastics, etc., as long as the material is durable enough to withstand the pressure and is chemically compatible with the fluids used.

[0022] All dimensions, configurations, etc. discussed herein may be varied as needed or desired, so that they differ from the values ​​or features specifically mentioned herein or shown in the drawings for each of the embodiments. Industrial applicability

[0023] In practice, a valve assembly and / or valve component, such as a spool, constructed according to an embodiment disclosed herein may be sold, purchased, manufactured, or otherwise acquired in an OEM (original equipment manufacturer) or aftermarket context. In some cases, various components of the valve assembly and spool may be provided as a kit for field repair or retrofitting of a hydraulic system or other device (e.g., a lubrication system, etc.).

[0024] While each of the modules may be manufactured using any suitable manufacturing technique, the use of certain manufacturing techniques for certain types of modules may provide additional advantages. For example, the first, second, and third web modules 130, 140, and 160 may be manufactured using subtractive manufacturing. As used herein, the term "subtractive manufacturing" is intended to include operations in which a workpiece may be formed into an approximate net shape, such as by conventional casting or molding, and then formed into a final net shape by removing material from the workpiece, such as by milling, grinding, cutting, sanding, knurling, drilling, turning, machining, and polishing. The use of subtractive manufacturing to form the first, second, and third web modules 130, 140, and 160 may reduce the time and cost required to manufacture these components.Furthermore, in some examples, the first and second dispensing modules 150, 170 may be manufactured using additive manufacturing. As used herein, the term "additive manufacturing" is intended to include processes in which material is deposited onto a substrate in successive layers to produce a workpiece, such as material jetting, binder jetting, powder bed fusion, stereolithography, sheet lamination, directed energy deposition, and material extrusion. Using additive manufacturing to form the first and second dispensing modules may reduce the time and cost of manufacturing the more intricate and complex shapes of the columns 184, 194, the end caps 152, 154, 172, and 174, and the dispensing pockets 156, 176.While the previous example uses subtractive manufacturing to form the web modules 130, 140 and 160 and additive manufacturing to form the dispensing modules 150 and 170, any suitable manufacturing technique can be used to manufacture the modules 130, 140, 150, 160 and 170.

[0025] Fig.7 shows a method 300 for forming the spool 120 for use with the housing 102. The directional control valve housing 102 has a housing inner surface 104 defining the spool cavity 106. The method 300 includes, at block 302, forming the first land module 130 with the first land module circumferential surface 132 dimensioned to be in sliding contact with the housing inner surface 104. At block 304, the method includes forming the second land module 140 with the second land module circumferential surface 142 dimensioned to be in sliding contact with the housing inner surface 104. At block 306, the first metering module 150 is formed using additive manufacturing with the first end cap 152 and the second end cap 154. In block 308, the first end cap 152 of the first dosing module 150 is coupled to the first web module 130, and in block 310, the second end cap 154 ​​of the first dosing module 150 is coupled to the second web module 140.In the assembled state, the first web module 130, the first dosing module 150 and the second web module 140 extend successively along a coil longitudinal axis.

[0026] Optionally, the method 300 further includes, in block 312, forming the third land module 160 with the third land module circumferential surface 162 dimensioned to be in sliding contact with the housing inner surface 104. In block 314, the method 300 may further include forming the second dosing module 170 with the first end cap 172 and the second end cap 174 by additive manufacturing. Furthermore, the method 300 may include coupling the first end cap 172 of the second dosing module 170 to the second land module 140 in block 316 and coupling the second end cap 174 of the second dosing module 170 to the third land module 160 in block 318, wherein the second dosing module 170 and the third land module 160 extend along the coil longitudinal axis. In some examples, the first web module 130, the second web module 140, and the third web module 160 are each formed by subtractive manufacturing.

[0027] In some examples, forming the first dosing module 150 using additive manufacturing (in block 306) further includes forming the at least two columns 184 of the first dosing module 150 extending between the first end cap 152 of the first dosing module 150 and the second end cap 154 ​​of the first dosing module 150, wherein the at least two columns 184 of the first dosing module 150 are disposed entirely within the virtual hollow cylinder region 182 of the first dosing module.Similarly, forming the second dosing module 170 using additive manufacturing (in block 314) further includes forming the at least two columns 194 of the second dosing module 170 extending between the first end cap 172 of the second dosing module 170 and the second end cap 174 of the second dosing module 170, wherein the at least two columns 194 of the second dosing module 170 are disposed entirely within the virtual hollow cylinder region 192 of the second dosing module.

[0028] In still further examples, forming the first dosing module 150 (in block 306) using additive manufacturing also includes forming the at least one dosing pocket 156 in each of the first end cap 152 and the second end cap 154 ​​of the first dosing module 150, and forming the second dosing module 170 (in block 314) using additive manufacturing also includes forming the at least one dosing pocket 176 in each of the first end cap 172 and the second end cap 174 of the second dosing module 170.

[0029] From the foregoing, it will be appreciated that, although only certain embodiments have been set forth for purposes of illustration, alternatives and modifications will be apparent to those skilled in the art from the foregoing description. These and other alternatives are considered equivalent and within the spirit and scope of this disclosure and the appended claims.

Claims

[1] Coil (120) defining a coil longitudinal axis (122), the coil (120) comprising: a first web module (130) defining a first web module peripheral surface (132); a second web module (140) defining a second web module peripheral surface (142); and a first dosing module (150), wherein: a first end cap (152) of the first dosing module (150) is coupled to the first web module (130); and a second end cap (154) of the first dosing module (150) is coupled to the second web module (140), characterized by , that the first dosing module (150) defines a virtual central core region (180) of the first dosing module, which is concentric with the coil longitudinal axis (122), and a virtual hollow cylinder region (182) of the first dosing module, which surrounds the virtual central core region (180) of the first dosing module; and at least two columns (184) of the first dosing module (150) extend between the first end cap (152) of the first dosing module (150) and the second end cap (154) of the first dosing module (150), wherein the at least two columns (184) of the first dosing module (150) are arranged entirely within the virtual hollow cylinder region (182) of the first dosing module. [2] The spool (120) of claim 1, wherein each of the first end cap (152) and the second end cap (154) of the first dosing module (150) defines at least one dosing pocket (156). [3] The spool (120) of claim 2, wherein each of the first end cap (152) and the second end cap (154) of the first dosing module (150) includes a beveled surface (158) and each of the at least one dosing pocket (156) extends into a corresponding beveled surface (158) of the first end cap (152) and the second end cap (154) of the first dosing module (150). [4] Coil (120) according to claim 1, wherein the first dosing module (150) is screwably coupled to the first web module (130) and the second web module (140). [5] Coil (120) according to any one of the preceding claims, wherein each of the at least two columns (184) of the first dosing module (150) has a circular cross-section (200). [6] The coil (120) of any one of claims 1 to 4, wherein each of the at least two columns (184) of the first dosing module (150) has a non-circular cross-section (210), the non-circular cross-section (210) including a major axis (212) and a minor axis (214). [7] The coil (120) of claim 1, further comprising: a third web module (160) defining a third web module peripheral surface (162); and a second dosing module (170), wherein: a first end cap (172) of the second dosing module (170) is coupled to the second web module (140); and a second end cap (174) of the second dosing module (170) is coupled to the third web module (160). [8] Coil (120) according to claim 7, wherein: the first dosing module (150) defines a virtual central core region (180) of the first dosing module that is concentric with the coil longitudinal axis (122) and a virtual hollow cylinder region (182) of the first dosing module that surrounds the virtual central core region (180) of the first dosing module; at least two columns (184) of the first dosing module (150) extend between the first end cap (152) of the first dosing module (150) and the second end cap (154) of the first dosing module (150), wherein the at least two columns (184) of the first dosing module (150) are arranged entirely within the virtual hollow cylinder region (182) of the first dosing module; the second dosing module (170) defines a virtual central core region (190) of the second dosing module, which is concentric with the coil longitudinal axis (122), and a virtual hollow cylinder region (192) of the second dosing module, which surrounds the virtual central core region (190) of the second dosing module; and at least two columns (194) of the second dosing module (170) extend between the first end cap (172) of the second dosing module (170) and the second end cap (174) of the second dosing module (170), wherein the at least two columns (194) of the second dosing module (170) are arranged entirely within the virtual hollow cylinder region (192) of the second dosing module. [9] Coil (120) according to claim 8, wherein: the first end cap (152) and the second end cap (154) of the first dosing module (150) each define at least one dosing pocket (156); and the first end cap (172) and the second end cap (174) of the second dosing module (170) each define at least one dosing pocket (176). [10] Coil (120) according to claim 9, wherein: the first end cap (152) and the second end cap (154) of the first dosing module (150) each comprise a beveled surface (158) and each of the at least one dosing pocket (156) extends into a corresponding beveled surface (158) of the first end cap (152) and the second end cap (154) of the first dosing module (150); and the first end cap (172) and the second end cap (174) of the second dosing module (170) each comprise a beveled surface (178) and each of the at least one dosing pocket (176) extends into a corresponding beveled surface (178) of the first end cap (172) and the second end cap (174) of the second dosing module (170). [11] Coil (120) according to claim 7, wherein: the first dosing module (150) is screwably coupled to the first web module (130) and the second web module (140); and the second dosing module (170) is screwably coupled to the second web module (140) and the third web module (160). [12] Directional control valve assembly (100) comprising: a housing (102) having an inner housing surface (104) defining a coil cavity (106), the housing (102) further defining a first through-opening (108), a second through-opening (110), and a third through-opening (112), each of the first through-opening (108), the second through-opening (110), and the third through-opening (112) extending through the inner housing surface (104) and being in fluid communication with the coil cavity (106); a coil (120) according to any one of claims 7-11. [13] A method (300) for forming a coil (120) for use with a housing (102) having a housing inner surface (104) defining a coil cavity (106), the method (300) comprising: Forming (302) a first web module (130) having a first web module peripheral surface (132) dimensioned for sliding contact with the housing inner surface (104); Forming (304) a second web module (140) having a second web module peripheral surface (142) dimensioned for sliding contact with the housing inner surface (104); Forming (306) a first dosing module (150) with a first end cap (152) and a second end cap (154) by additive manufacturing; Coupling (308) the first end cap (152) of the first dosing module (150) to the first web module (130); and coupling (310) the second end cap (154) of the first dosing module (150) to the second web module (140); wherein the first web module (130), the first dosing module (150) and the second web module (140) extend along a coil longitudinal axis (122), characterized by Forming (312) a third web module (160) having a third web module peripheral surface (162) dimensioned for sliding contact with the housing inner surface (104); Forming (314) a second dosing module (170) with a first end cap (172) and a second end cap (174) by additive manufacturing; coupling (316) the first end cap (172) of the second dosing module (170) to the second web module (140); and Coupling (318) the second end cap (174) of the second dosing module (170) to the third web module (160); wherein: the second dosing module (170) and the third web module (160) extend along the coil longitudinal axis (122); the first dosing module (150) defines a virtual central core region (180) of the first dosing module, which is concentric with the coil longitudinal axis (122), and a virtual hollow cylinder region (182) of the first dosing module, which surrounds the virtual central core region (180) of the first dosing module; and Forming (306) the first dosing module (150) by means of additive manufacturing further comprises forming at least two columns (184) of the first dosing module (150) that extend between the first end cap (152) of the first dosing module (150) and the second end cap (154) of the first dosing module (150), wherein the at least two columns (184) of the first dosing module (150) are arranged entirely within the virtual hollow cylinder region (182) of the first dosing module.

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