Catalyst unit and exhaust catalyst

Abstract

Catalyst unit (10) for an exhaust gas catalyst, in particular an SCR catalyst unit for an SCR exhaust gas catalyst of a marine diesel internal combustion engine, comprising several catalyst modules (11), wherein each catalyst module (11) has a ceramic catalyst body through which exhaust gas flows and a metallic housing (12) for the ceramic catalyst body, the respective ceramic catalyst body being received in the respective metallic housing (12) and partially surrounded by it. The catalyst modules (11) are positioned with their first flow-through ends on a support grid (13), with a counter-support (14) being positioned at the opposite second flow-through ends of the catalyst modules (11).The catalyst modules (11) are clamped between the support grid (13) and the counterholder (14), the counterholder (14) having several parallel counterholder struts (21) which engage a housing structure (27a) of an exhaust gas catalyst at a first end (22) and interact at opposite second ends (23) with a retainer strut (24) extending perpendicular to the counterholder struts (21). The counterholder struts (21) are connected at their second ends (23) to the retainer strut (24) via connecting means (25) extending in the axial direction of the counterholder struts (21) such that, as a result of the connection, the counterholder struts (21) press against structural elements (29) of the housing structure (27a) at their first ends (22).

Description

[0001] The invention relates to a catalyst unit according to the preamble of claim 1. The invention further relates to an exhaust gas catalyst.

[0002] A catalyst unit for an exhaust gas catalyst comprises several catalyst modules. Each catalyst module has a ceramic catalyst body through which exhaust gas flows and a metallic, rectangular-section housing for the ceramic catalyst body, also referred to as a canning. The housing of each catalyst module accommodates and partially surrounds the respective catalyst body, leaving open ends of the catalyst body through which the exhaust gas flows. One open end provides an inflow and the other an outflow of the respective catalyst body.

[0003] In conventional catalyst units, the catalyst modules are arranged in an array-like fashion in multiple rows and columns, with immediately adjacent catalyst modules being firmly connected in the area of ​​their metallic, rectangular-section housings, particularly by welding. When a catalyst module in a catalyst unit needs to be replaced, these welded connections must be broken, for example, by grinding, which can damage adjacent catalyst modules. Connecting adjacent catalyst modules by welding is therefore disadvantageous. Documents DE 15 67 474 B2, DE 35 12 102 A1, DE 10 2011 001 367 A1, and US 2009 / 0 293 464 A1 disclose further possibilities for positioning exhaust aftertreatment components in the exhaust system; however, these also share the common characteristics that replacing the components is difficult and / or maintaining component tolerances is very demanding.

[0004] Therefore, there is a need for a catalyst unit for a catalyst, on which catalyst modules can be replaced more easily.

[0005] Starting from this premise, the present invention aims to create a novel catalyst unit for an exhaust gas catalyst and an exhaust gas catalyst incorporating such a catalyst unit. This objective is achieved by a catalyst unit according to claim 1. According to the invention, the catalyst modules are positioned with their first flow-through ends on a support grid, with a counter-holder positioned at the opposite second flow-through ends of the catalyst modules. The catalyst modules are clamped between the support grid and the counter-holder. The counter-holder has several counter-holder struts extending parallel to one another, which engage a housing structure of an exhaust gas catalyst at a first end and interact at opposite second ends with a retainer strut extending perpendicular to the counter-holder struts.The counter-support struts are connected at their second ends to the retaining strut via connecting means extending in the axial direction of the counter-support struts, such that, as a result of the connection, the counter-support struts press against structural elements of the housing structure at their first ends. The invention allows for the simple, trouble-free replacement of catalyst modules of a catalyst unit without risk of damage to adjacent catalyst modules and for the secure clamping of the catalyst modules between the support grid and the counter-support.

[0006] In a further advantageous development, the counter-support struts press with their first ends against inclined contours of the structural elements of the housing structure, such that the counter-support struts exert a clamping force on the catalyst modules in the region of their first ends. This allows the catalyst modules to be clamped particularly advantageously between the support grid and the counter-support.

[0007] With a further advantageous development, a force can be applied to all counter-support struts in the region of their second ends via the clamping strut for clamping the catalyst modules between the support grid and the counter-support. This allows the catalyst modules to be clamped particularly advantageously between the support grid and the counter-support.

[0008] Preferably, a clamping force can be applied to the retaining strut via pressure plates that act on the retaining strut on one side and on the housing structure of the exhaust gas catalyst on the other. This allows the catalyst modules to be clamped particularly advantageously between the support grid and the counter-holder.

[0009] In a further advantageous development, spring elements elastically support the retaining strut on the housing structure of the exhaust gas catalyst and / or the counter-support struts on the catalyst modules and / or the retaining strut. This elastic support is advantageous for compensating for temperature-related expansion.

[0010] The exhaust gas catalyst according to the invention is defined in claim 10.

[0011] Preferred embodiments of the invention are described in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. The drawing shows: Fig. 1: a perspective view of a catalyst unit according to the invention for an exhaust gas catalyst; Fig. 2: a cross-section through the catalyst unit of the Fig. 1; Fig. 3: the catalyst unit of the Fig. 1 without counterweight; Fig. 4: the counterholder of the catalyst unit of the Fig. 1; Fig. 5: Detail V of the Fig. 1; and Fig. 6: Detail VI of the Fig. 1.

[0012] The invention relates to a catalyst unit for an exhaust gas catalyst of an internal combustion engine for ship or marine applications and an exhaust gas catalyst. In particular, the catalyst unit according to the invention is designed as an SCR catalyst unit for an SCR exhaust gas catalyst of a marine diesel internal combustion engine. Fig. 1 to Fig. Figure 6 shows different views and details of a preferred embodiment of a catalyst unit.

[0013] The catalyst unit 10 according to the invention comprises several catalyst modules 11, wherein the catalyst modules 11 are positioned adjacent to one another in an array-like arrangement in columns and rows. Each catalyst module 11 has a metallic housing 12, which accommodates a ceramic catalyst body (not shown). In the illustrated embodiment, the metallic housings 12 have a rectangular cross-section, and these housings 12 partially surround a rectangular catalyst body on the outside. The housing 12, which is also referred to as a canning, leaves the catalyst body exposed at opposite ends, forming an inlet and an outlet of the respective catalyst module 11.

[0014] The catalyst unit 10 has a support grid 13. The catalyst modules 11 rest on the support grid 13 at their first flow-through ends. A counter-holder 14 is positioned at the opposite second flow-through ends of the catalyst modules 11, with the catalyst modules 11 being clamped between the support grid 13 and the counter-holder 14.

[0015] What is the best way? Fig. The support grid 13, which can be removed from the first support struts 15a running parallel to each other, has several second support struts 15b running parallel to each other and perpendicular to the first support struts 15a, on which the catalyst modules 11 are positioned.

[0016] Between the directly parallel support struts 15a and 15b of the support grid 13, on which directly adjacent catalyst modules 11 are positioned, there is a sealing element 16 (see Fig. 6) arranged, which prevents exhaust gas flow between the housings 12 of immediately adjacent catalyst modules 11. Thus, in Fig. Figure 6 shows a gap 17 between the housings 12 of two immediately adjacent catalyst modules 11, wherein the sealing element 16 prevents exhaust gas flow through this gap 17 and thus ensures that all exhaust gas flow passes through the catalyst bodies of the catalyst modules 11. The in Fig. 6 visible sealing element 16 is positioned on a U-shaped profiled profile carrier 18, which is in Fig. 6 is positioned between the support struts 15b of the support grid 13 which run directly parallel to each other.

[0017] How Fig. As can be seen from section 6, the housings 12 of the catalyst modules 11 have bent or flanged support feet 19 at their first flow-through ends, which are supported by or rest on a sealing element 16. If the wall thickness of the canning at the ends is sufficient, a flange can be omitted. The wall thickness must be between 2 mm and 20 mm for this to be possible. Between the support struts 15a, 15b and the first flow-through ends of the catalyst modules 11, there is a Fig. 6 a gap 20 is formed, which, however, preferably disappears after the catalyst modules 11 are clamped between the support grid 13 and the counterholder 14.

[0018] How Fig. Each catalyst module 11 interacts with individual support struts 15a, 15b of the support grid 13. The catalyst modules 11 engage with their support feet 19 in the spaces defined between immediately adjacent support struts 15a and 15b, in which the sealing elements 16 are positioned. In this way, the parallel support struts 15a, 15b provide individual tolerance compensation for dimensional tolerances of the catalyst modules 11, so that the individual tolerances of adjacent catalyst modules 11 do not add up. This allows the catalyst unit 10 according to the invention to be integrated particularly advantageously into a housing structure of an exhaust gas catalyst.

[0019] As already explained, the catalyst modules 11 are clamped between the support grid 13 and the counterholder 14. The counterholder 14 has several counterholder struts 21 running parallel to each other. Each of the counterholder struts 21 engages a housing structure 27a of the exhaust catalyst with a first end 22, and a retaining strut 24 extending perpendicular to the counterholder struts 21 interacts with them at a second end 23 opposite the counterholder struts 21.

[0020] A clamping force can be applied to the counter-support struts 21 via the retaining strut 24 to clamp the catalyst modules 11 between the support grid 13 and the counter-support 14. This clamping force presses the counter-support struts 23 against the housings 12 of the catalyst modules 11, and thus ultimately presses the catalyst modules 11 against the support grid 13, thereby clamping the catalyst modules 11 between the support grid 13 and the counter-support 14.

[0021] The counter-support struts 21, which extend along two immediately adjacent rows or columns of catalyst modules 11, are supported on the catalyst modules 11 of these immediately adjacent rows or columns. Only the outer counter-support struts 21 are supported solely on the catalyst modules 11 of a single row or column.

[0022] The clamping force to be applied via the hold-down strut 24 to the counter-support struts 21 of the counter-support 14 is provided in the illustrated embodiment by two depressors 26, which engage opposite ends of the hold-down strut 24. Each depressor 26 engages the hold-down strut 24 at one end and a housing structure 27b of a catalyst housing at the other, whereby the distance between the housing structure 27b and the hold-down strut 24, and thus the clamping force, can be adjusted via the nuts 28 interacting with the depressor 26.

[0023] The counter-support struts 21 are connected at their second ends 23 to the hold-down strut 24 via connecting means 25 extending in the axial direction of the counter-support struts 21, such that as a result of the connection, the counter-support struts 21 press with their first ends 22 against structural elements 29 of the housing structure 27a. How best Fig.As can be seen from section 5, the connecting means 25 extend both through a flange section 30 at the second end 23 of the respective support strut 21 and through the common hold-down strut 24 for the support struts 21, namely in the axial direction or longitudinal direction of the support struts 21. Through the connection, which is preferably realized via connecting screws, a force acting in the axial or longitudinal direction of the support struts 21 is exerted on the support struts 21, causing the support struts 21 to press with their first ends 22 against inclined contours 31 of the structural elements 29 of the housing structure 27a. In this way, the support struts 21 exert a further clamping force on the catalyst modules 11 in the region of their first ends 22.

[0024] The clamping force required to clamp the catalyst modules 11 between the support grid 13 and the counterholder 14 is therefore applied on the one hand via the hold-down strut 24 and the second ends 23 of the counterholder struts 21 and on the other hand via the interaction of the connecting means 25 and the structural elements 29 of the housing structure 27a with the counterholder struts 21 via the first ends 22 of the counterholder struts 21 onto the housings 12 of the catalyst modules 11.

[0025] According to an advantageous further development of the invention, it is provided that the counterholder 14 is elastically supported on the housing structure 27b, namely via spring elements 32 which are supported between the hold-down strut 24 and the housing structure 27b in the area of ​​the push-down depressors 26.

[0026] Likewise, the catalyst unit 10 can be elastically supported by spring elements (not shown) that act between the support grid 13 and a housing structure 27c of a catalyst housing of an exhaust gas catalyst.

[0027] Furthermore, it is possible that spring elements not shown are provided which elastically support the counter-support struts 21 against the housings 12 of the catalyst modules 11 and / or the hold-down strut 24 and / or the housing structure 29.

[0028] Such spring elements can compensate for changes in the geometry of the catalyst unit 10 caused by temperature cycles. Additionally, it is possible to make the counter-supports elastic, particularly by using spring steel.

[0029] The catalyst unit 10 according to the invention therefore comprises several catalyst modules 11, which are arranged in an array-like manner in columns and rows positioned directly adjacent to one another. The catalyst modules 11 are supported at their first ends by their rectangular housings 12 on a static support grid 13. A counter-support 14 is arranged on the opposite side of the catalyst modules 11, comprising several movable counter-support struts 21 and a retaining strut 24. The catalyst modules 11 are clamped between the static support grid 13 and the movable counter-support 14.

[0030] Each counter-support strut 21 engages a housing structure 27a of the exhaust gas catalyst housing at a first end 22. At the opposite second end 23 of the counter-support struts 21, the common hold-down strut 24 engages to ultimately clamp the catalyst modules 11 between the support grid 13 and the counter-support 14. A first clamping force can be applied to the hold-down strut 24 via the hold-down strut 26 and to the second ends 23 of the counter-support struts 21 via the hold-down strut 24. A second clamping force is applied to the first end 22 of the counter-support struts 21 via the interaction of the connecting elements 25 and the inclined contour 31 of the structural elements 29 of the housing structure 27a.

[0031] The contours 31 of the structural elements 29 of the housing structure 27a are inclined such that the first end 22 of the counter-support struts 21 presses more strongly against the housings 12 of the catalyst modules 11 the more strongly the first ends 22 of the counter-support struts 21 are pressed in the axial direction or longitudinal direction by tightening the connecting means 25 against the housing structure 27a or the structural elements 29 of the housing structure 27a, namely against the contours 31 of the structural elements 29.

[0032] Thermal expansions of the catalyst unit 10 are preferably compensated by spring elements that act on the support grid 13 and / or on the retainer strut 24 and / or on the counter-support struts 21. An alternative for providing compensation for thermal expansions is to manufacture the counter-support struts 21 and preferably the retainer strut 24 of the counter-support 14 from an elastic material, in particular spring steel. This allows any thermal expansions that may occur to be absorbed and compensated directly by the counter-support 14.

[0033] Several such catalyst units 10 can be used in one housing of an exhaust gas catalyst. Reference symbol list 10 catalyst unit 11 Catalyst module 12 cases 13 support grids 14 Counterholds 15a Support strut 15b Support strut 16 Sealing element 17 gaps 18 profile beams 19 support foot 20 gaps 21 Counter support strut 22 End 23 End 24 hold-down strut 25 Fasteners 26 pressure plates 27a Housing structure 27b Housing structure 27c Housing structure 28 Mother 29 Structural element 30 Flange section 31 contour 32 spring element

Claims

[1] Catalyst unit (10) for an exhaust gas catalyst, in particular an SCR catalyst unit for an SCR exhaust gas catalyst of an internal combustion engine, with several catalyst modules (11), wherein each catalyst module (11) has a ceramic catalyst body through which exhaust gas flows and a metallic housing (12) for the ceramic catalyst body, wherein the respective ceramic catalyst body is received in the respective metallic housing (12) and is partially surrounded by it, characterized bythat the catalyst modules (11) are positioned with their first flow-through ends on a support grid (13), that a counterholder (14) is positioned at the opposite second flow-through ends of the catalyst modules (11), wherein the catalyst modules (11) are clamped between the support grid (13) and the counterholder (14), that the counterholder (14) has several counterholder struts (21) extending parallel to each other, which engage at a first end (22) a housing structure (27a) of an exhaust gas catalyst and cooperate at opposite second ends (23) with a retainer strut (24) extending perpendicular to the counterholder struts (21), wherein the counterholder struts (21) are connected at their second ends (23) to the retainer strut (24) via connecting means (25) extending in the axial direction of the counterholder struts (21),that as a result of the connection, the counter-support struts (21) press with their first ends (22) against structural elements (29) of the housing structure (27a). [2] Catalyst unit according to claim 1, characterized by , that the counter-support struts (21) with their first ends (22) press against inclined contours (31) of the structural elements (29) of the housing structure (27a), namely in such a way that the counter-support struts (21) exert a clamping force on the catalyst modules (11) in the area of ​​their first ends (22). [3] Catalyst unit according to claim 1 or 2, characterized by , that a force can be applied to all counterholder struts (21) in the area of ​​their second ends (23) via the retaining strut (24) for clamping the catalyst modules (11) between the support grid (13) and the counterholder (14). [4] Catalyst unit according to claim 3, characterized by, that a clamping force can be applied to the retaining strut (24) via pressure plates (26), which act on the retaining strut (24) on one side and on the other side on the housing structure (27) of the exhaust catalyst. [5] Catalyst unit according to any one of claims 1 to 4, characterized by , that spring elements (32) elastically support the retaining strut (24) on the housing structure (27) of the exhaust catalyst. [6] Catalyst unit according to claim 5, characterized by , that spring elements elastically support the counter-support struts (21) on the catalyst modules (11) and / or on the hold-down strut (24) and / or on the structural elements (29). [7] Catalyst unit according to any one of claims 1 to 6, characterized by , that the structural elements (29) are elastically mounted relative to the housing structure (27). [8] Catalyst unit according to any one of claims 1 to 7, characterized by that the counter-supports (21) are designed to be elastic. [9] Catalyst unit according to claim 8, characterized by that the counterholders (21) are made of spring steel. [10] Exhaust gas catalyst, comprising several catalyst units (10) according to any one of claims 1 to 9.

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