The present disclosure relates generally to exhaust treatment and, more particularly, to an assembly and a method of assembly for exhaust treatment.
Internal combustion engines, including diesel engines, gasoline engines, natural gas engines, and other engines known in the art, may exhaust a complex mixture of air pollutants. The air pollutants may be composed of gaseous compounds, which may include nitrous oxides (NOx), and/or other harmful pollutants. Due to increased attention on the environment, exhaust emission standards have become more stringent, and the amount of NOx, and/or other harmful pollutants emitted to the atmosphere from an engine may be regulated depending on the type of engine, size of engine, and/or class of engine.
One method that has been implemented by engine manufacturers to comply with the regulation of these engine emissions has been to equip engines with ceramic filter elements. These ceramic filter elements may react with exhaust to reduce the amount of NOx, and/or other harmful pollutants, emitted. Such ceramic filter elements are sometimes packaged into filter assembly, sometimes referred to as a reactor unit. This may include a stainless steel box-shape structure enclosing an internal honey-comb type metal structure with the ceramic filter elements in each compartment of the honey-comb structure, and with outer walls and grids around the ceramic filter elements to provide structural integrity. These outer wall and grids are often made from stainless steel or other suitable metal.
One filter assembly is disclosed in U.S. Pat. No. 5,228,892 (the '892 patent), issued to Akitsu et al. on Jul. 20, 1993. In the '892 patent, the filter assembly may include a pair of side plates that may be integrally assembled in a square framework by the use of brackets. The '892 patent also discloses that a plurality of ceramic filter elements may be aligned in parallel within the square framework, and may be clamped by the pair of side plates. The use of the side plates, the brackets, and the square framework may require extensive consumption of stainless steel or other suitable metal, which may be expensive. Also, gaps may exist between the ceramic filter elements in the filter assembly of the '892 patent because no sealant is applied to the ceramic filter elements and their respective support structure. The existence of such gaps would, in turn, decrease the efficiency of the filter assembly.
The disclosed assembly and method of assembly for exhaust treatment are directed to improvements in the exiting technology.
In one aspect, the present disclosure is directed to an exhaust treatment assembly. The exhaust treatment assembly may include a plurality of first grid members. The exhaust treatment assembly may also include a plurality of second grid members engaged with the plurality of first grid members. The first and second grid members may be arranged to form spaces between the grid members. The exhaust treatment assembly may further include a plurality of exhaust filter elements disposed in the spaces and forming an exhaust filter block. The exhaust treatment assembly may also include a first side wall engaged with the plurality of first grid members. The first side wall may be adjacent a first edge of the exhaust filter block. The exhaust treatment assembly may further include a second side wall engaged with the plurality of second grid members. The second side wall may be adjacent a second edge of the exhaust filter block. Moreover, the exhaust treatment assembly may include an insulator located between the first side wall and the first edge of the exhaust filter block, and located between the second side wall and the second edge of the exhaust filter block.
In another aspect, the present disclosure is directed to a method of assembling an exhaust treatment assembly. The method may include providing a plurality of first grid members, each one of the first grid members having a locking member. The method may also include engaging the plurality of first grid members with a plurality of second grid members, each one of the second grid members having a locking member, and the plurality of first and second grid members forming a grid with spaces between the engaging plurality of first and second grid members. The method may further include positioning a plurality of exhaust filter elements in the spaces and forming an exhaust filter block. The method may also include wrapping a perimeter of the exhaust filter block with an insulator. The method may further include engaging a first side wall with the plurality of first grid members, the first side wall having openings configured to receive the locking members of the plurality of first grid members. Moreover, the method may include engaging a second side wall with the plurality of second grid members, the second side wall having openings configured to receive the locking members of the plurality of second grid members.
First grid members 14 and second grid members 20 may be positioned within grid element 12 so as to form spaces 40. Spaces 40 may be, for example, generally square. Exhaust filter elements 42 may also be generally square. Exhaust filter elements 42 may be made of any appropriate type of materials employed in the art. For example, exhaust filter elements 42 may be ceramic. It is contemplated that spaces 40 may assume other geometric shapes, and similarly, exhaust filter elements 42 may assume other geometric shapes. For example, spaces 40 and exhaust filter elements 42 may be generally circular in shape. It is also contemplated that spaces 40 may assume geometric shapes that are different from the shapes of exhaust elements 42.
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For example, exhaust filter block 43 may be formed by securing sixteen exhaust filter elements 42 together. On the other hand, four exhaust filter units may be formed with each exhaust filter units formed by securing four of the sixteen exhaust filter elements 42 together. The four exhaust filter units may then be secured together to form exhaust filter block 43. It is contemplated that exhaust filter block 43 may be formed by securing more or less than sixteen exhaust filter elements 42. Similarly, exhaust filter units may be formed by securing more or less than four exhaust filter elements 42.
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The disclosed exhaust treatment assembly may be applicable to any machine where treatment of exhaust is desired.
Exhaust treatment assembly 10 may be assembled by engaging first grid elements 14 and second grid elements 20 to form grid element 12. A plurality of exhaust filter elements 42 may then be disposed within grid element 12 and may be secured together to form exhaust filter block 43. Grid element 12 may assume any appropriate geometric shapes. For example, grid element 12 may be generally square in cross section and planar in shape. Alternatively, grid element 12 may be generally circular in cross section and planar in shape. The different geometric shapes may help to facilitate the use of grid element 12 in various applications of exhaust treatment where different geometric limitations are required. Sealant may be applied to the engagement between the plurality of exhaust filter elements 42. Exhaust filter block 43 may also be wrapped with insulator 45. Each one of the first grid members 14 and second grid members 20 may include a locking mechanism 50 at one or both ends. Locking mechanism 50 may include a first portion, such as alignment member 52, and a second portion, such as twist tab 54. Twist tab 54 may extend from top surface 56 of alignment member 52. Side walls 44 may engage grid element 12 and exhaust filter block by extending twist tab 54 through opens 46 of side walls 44. Because the width of alignment member 52 may be substantially equal to the width of one opening 46, locking mechanism 50 may facilitate assembling of exhaust treatment assembly 10 and provide more accurate positioning for the engagement of side walls 44 with first and second grid members 14 and 20.
The application of sealant between each one of exhaust filter elements 42 to form exhaust filter block 43 may help to reduce the possibility of a gap existing within exhaust filter block 43. The surrounding of exhaust filter block 43 with insulator 45 may also help to reduce the likelihood of a gap existing within exhaust filter block 43. The application of sealant and the surrounding of exhaust filter block 43 with insulator 45 may also help to enhance the structural integrity of exhaust filter block 43. The existence of gap within exhaust filter block 43 may allow exhaust to pass through the gap without passing through exhaust filter elements 42. Therefore, the reduction in the possibility of a gap existing within exhaust filter block 43 may improve the efficiency of exhaust filter block 43 and reduce emission.
Insulator 45 may also help to dampen vibration and impulses experienced by exhaust filter block 43 during the operation of a machine equipped with exhaust treatment assembly 10. In addition, insulator 45 may help to provide thermo-retardation of exhaust filter block 43 during the operation of a machine equipped with exhaust treatment assembly 10. The use of sealant and insulator 45 may further help to reduce the metal needed to ensure the structural integrity of exhaust filter block 43. Consequently, the cost of assembling and manufacturing exhaust treatment assembly 10 may be reduced.
Any appropriate type of sealant may be applied to the interfaces (not shown) where side walls 44 engage exhaust filter block 43. The application of sealant to the interfaces may help to reduce the likelihood of a gap existing between side walls 44 and exhaust filter block 43. The reduction of the likelihood of a gap existing within exhaust treatment assembly 10, i.e., between side walls 44 and exhaust filter block 43, may also help to improve the efficiency of exhaust treatment assembly 10 and reduce emissions.
In addition, locking mechanism 50 may help to secure the engagement of grid element 12 with side walls 44. For example, one first grid member 14 may be engaged with one side wall 44 by inserting locking mechanism 50 of one first grid member 14 through one opening 46 of one side wall 44. After one first grid member 14 engages one side wall 44, the engagement between them may be strengthened by moving twist tab 54 from a first position to a second position as described above. The engagement between alignment member 52 and inner surfaces 61 and 62 may also be strengthened by welding interfaces 55 where alignment member 52 engages inner surfaces 61 and 62. Twist tab 54 may be removed by moving twist tab 54 with necessary force. The removal of twist tab 54 may form space 53, which may be filled with any appropriate material, such as a sealant or a filler. The application of the sealant to space 53 may help to reduce the likelihood of a gap existing at interfaces 55. Flanges 47 on side walls 44 and extension members 26 on second grid members 20 may facilitate installation of exhaust treatment assembly 10 into a machine and/or an engine where an exhaust treatment assembly is desired.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed exhaust treatment assembly. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed exhaust treatment assembly. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims.