This patent disclosure relates generally to a system and method for accommodating an aftertreatment brick in an aftertreatment system and, more particularly, to a system and method for releasably securing the aftertreatment brick inside the system.
Industrial scale power systems may include large internal combustion engines or similar devices that burn hydro-carbon based fuels or similar fuel sources to convert the chemical energy therein to mechanical energy that can be utilized to power an associated machine or application. The combustion of such fuel sources may create or release byproducts and emissions like hydrocarbons (H—C); carbon dioxide and carbon mono-oxide; nitrogen oxides (NO and NO2, commonly referred to a NOX) and particulate matter. The quantity or characteristics of these byproducts and emissions that can be discharged to the environment may be subject to governmental regulation. Accordingly, to treat the byproducts and emissions for compliance with possible regulations, the power systems may be associated with exhaust gas aftertreatment systems.
The aftertreatment system may be disposed in the exhaust channel of the power system and may include a unit or module through which the exhaust gasses may be directed. The aftertreatment module may utilize one or more aftertreatment devices that can remove or convert the byproducts and/or emissions in the exhaust gasses. Specifically, these devices may include aftertreatment bricks made of materials or substances that change, chemically or physically, the composition of the exhaust gasses that encounter the bricks. Examples of aftertreatment bricks include catalysts that chemically alter the exhausts and filters that can trap specific components of the exhaust gasses. Because some types of aftertreatment bricks may become depleted or deactivated over time, or may become damaged due to the conditions in which they operate, the aftertreatment bricks may be removable from the aftertreatment module.
An example of an aftertreatment system configured for removable catalysts is described in U.S. Pat. No. 5,169,604 (the '604 patent). The '604 patent describes a generally tubular housing assembly that establishes a flow path into which one or more catalyst carriers can be placed. To access the catalyst carriers inside the housing assembly, a removable cover covers a hatch disposed in the assembly. To lift the catalyst carriers through the hatch, a U-shaped removal means extends partially around the catalyst carriers. Hence, the catalyst carriers can be set inside and removed from the housing. The present disclosure is directed to enabling similar functionality in an aftertreatment system.
In an aspect, the disclosure describes a method of releasably securing an aftertreatment brick in an aftertreatment system. According to the method, a first bracket is installed in a brick compartment disposed along the exhaust flow path of the aftertreatment system. The first bracket may have a first surface complementary to a periphery of the aftertreatment brick. The aftertreatment brick is placed on the first bracket so that the first surface is adjacent a portion of the periphery of the brick. A second bracket is installed in the brick compartment and may include a second surface complementary to the periphery of the aftertreatment brick. The second bracket is installed so that the second surface is adjacent another portion of the periphery of the aftertreatment brick. A band clamp is secured about the first and second brackets to secure the first and second brackets to the aftertreatment brick.
In another aspect, the disclosure provides a releasable securing assembly for securing an aftertreatment brick inside an aftertreatment system. The assembly includes a first bracket having a first surface complementary to a periphery of the aftertreatment brick. The first bracket is adapted to be permanently installed in a brick compartment of the aftertreatment system. The assembly also includes a second bracket having a second surface also complementary to the periphery of the aftertreatment brick and which is adapted to be removably installed in the brick compartment. The assembly further includes a band clamp adapted to be secured about the first bracket and the second bracket to compress the first bracket and the second bracket about the aftertreatment brick.
In yet a further aspect, the disclosure provides another method for servicing an aftertreatment brick in an aftertreatment system. According to the method, a brick compartment is accessed through an access hatch to access the aftertreatment bricks. A band clamp is slid off a first bracket and a second bracket securing an aftertreatment brick in the brick compartment. The second bracket, proximate the hatch, is uninstalled and removed from the brick compartment. The aftertreatment brick may then be lifted from the first bracket and removed from the brick compartment.
This disclosure relates generally to an exhaust aftertreatment system that may be associated with a power system producing exhaust gasses and, more particularly, relates to aftertreatment bricks that may be a removable component of such aftertreatment systems. Now referring to the drawings, wherein like reference numbers refer to like elements, there is illustrated in
To direct intake air into and exhaust gasses from the power system 100, the power system can include an air introduction system 110 and an exhaust system 112. The air introduction system 110 introduces air or an air/fuel mixture to the combustion chambers of the internal combustion engine 102 for combustion while the exhaust system 112 includes an exhaust pipe or exhaust channel 114 in fluid communication with the combustion chambers to direct the exhaust gasses produced by the combustion process to the environment. To pressurize intake air by utilizing the positive pressure of the expelled exhaust gasses, the power system 100 can include one or more turbochargers 116 operatively associated with the air introduction system 110 and the exhaust system 112.
The exhaust system 112 can include components to condition or treat the exhaust gasses before they are discharged to the environment. For example, an exhaust aftertreatment system 120 in the form of a clean emissions module (CEM) can be disposed in fluid communication with the exhaust system 112 downstream of the turbochargers 116 to receive the exhaust gasses discharged from the internal combustion engine 102. The term “aftertreatment” refers to the fact that the system treats exhaust gasses after they have been produced and is therefore distinguishable from fuel additives and the like that affect the combustion process. The aftertreatment system 120 can be designed as a separate unit that can be mounted to the power system 100 generally over the generator 104, for example, and can receive exhaust gasses from the exhaust channel 114. By manufacturing the aftertreatment system 120 as a separate modular unit, the design can be utilized with different sizes and configurations of the power system 100. However, in other embodiments, the aftertreatment system 120 can be integral with the power system 100 and can be disposed at other locations rather than above the power system.
Referring to
To receive the untreated exhaust gasses into the aftertreatment system 120, one or more inlets 140 can be disposed through the first wall 126 of the housing 122 and can be coupled in fluid communication to the exhaust channel from the exhaust system. In the embodiment illustrated, the aftertreatment system 120 includes two inlets 140 arranged generally in parallel and centrally located between the third and fourth sidewalls 130, 132 on either side of the system axis line 134 so that the entering exhaust gasses are directed toward the rearward second wall 128. However, other embodiments of the aftertreatment system 120 may include different numbers of and/or locations for the inlets. To enable the exhaust gasses to exit the aftertreatment system 120, two outlets 142 can also be disposed through the first wall 126 of the housing 122. Each outlet 142 can be parallel to the centrally disposed inlets 140 and can be aligned adjacent to one of the respective third and fourth sidewalls 130, 132.
To treat or condition the exhaust gasses, the housing 122 can contain various types or kinds of exhaust treatment devices through or past which the exhaust gasses are directed. For example and following the arrows indicating exhaust flow through the aftertreatment system 120, in order to slow the velocity of the incoming exhaust gasses for treatment, the inlets 140 can each be communicatively associated with an expanding, cone-shaped inlet diffuser 144 mounted exteriorly of the front first wall 126. Each inlet diffuser 144 can direct the exhaust gasses to a compartment accommodating one or more aftertreatment bricks 150, specifically in the form of diesel oxidation catalysts (DOC) 152. Although
CO+½ O2=CO2 (1)
[HC]+O2=CO2+H2O (2)
After being directed through the DOCs 152, the aftertreatment system 120 may direct the exhaust gasses onto other devices to further reduce emissions. For example, to reduce nitrogen oxides such as NO and NO2, sometimes referred to as NOX, the aftertreatment system 120 may include a selective catalytic reduction (SCR) system 160. In the SCR process, a liquid or gaseous reductant agent is introduced to the exhaust system and directed through an SCR catalyst along with the exhaust gasses to convert the NOX to nitrogen (N2) and water (H2O). A common reductant agent is urea ((NH2)2CO), though other suitable substances such as ammonia (NH3) can be used in the SCR process. The reaction may occur according to the following general formula:
NH3+NOX=N2+H2O (3)
Referring to
As is apparent from the foregoing description, aftertreatment bricks are available in different types and styles to perform different aftertreatment processes, including as mentioned herein, DOC and SCR processes. Referring to
To protect the support structure 182, a tubular mantle 190 can be generally disposed around the substrate matrix 180. The tubular mantle 190 can be made of a thicker or more rigid material than the thin-walled support structure 182, such as aluminum or steel. For example, the mantle may be about 5/16 of an inch thick to provide sufficient structural rigidity to the catalyst. The mantle 190 can be generally cylindrical to correspond to the cylindrical shape of the substrate matrix 180, although in other embodiments, different shapes are contemplated. The tubular mantel 190 can extend between a circular first rim 192 and a corresponding circular second rim 194 that are opened so that exhaust gasses may access the substrate matrix 180. In the illustrated embodiment, the diameter of first and second rim 192, 194 delineates a diameter 196 of the aftertreatment brick while the distance between the first and second rims delineates a length 198 of the aftertreatment brick. By way of example only, the diameter 196 may be approximately 14 inches and the length 198 may be approximately 8 inches.
Disposed around the exterior of the mantle 190 can be one or more circumferentially extending, protruding ribs 199. The ribs 199 may be formed into the tubular skin of the mantle 190 and can protrude, for example, about 0.25 inches beyond the diameter 196. In the illustrated embodiment, two ribs 199 are provided with a first rib oriented toward, but set back from, the first rim 192 and a second rib oriented towards, but set back from, the second rim 194. Furthermore, in some embodiments, the substrate matrix 180 may be coextensive with the length 198 of the mantle such that the first and second faces 186, 188 are flush with the respective first and second rims 192, 194 while, in other embodiments, the first and second faces can be set back from the first and second rims for protection.
Referring back to
To receive the incoming exhaust gasses from the inlets 140, one or more entry ports 210 can be disposed through the front wall 202 and to discharge the gasses, one or more exit ports 212 can be disposed through the rear wall 204. In the particular embodiment illustrated, one entry port 210 and one exit port 212 may be provided for each of the two inlets 140 included with the aftertreatment module 120. Further, each associated entry port 210 and exit port 212 can be generally aligned along a port axis 214 extending between the front and rear walls 202, 204 and that is parallel to the system axis line 134. The entry ports 210 and the exit ports 212 may generally correspond in shape and size to the circular aftertreatment bricks 150, e.g., circular. When installed in the compartment, the aftertreatment bricks 150 may be positioned between the entry and exit ports 210, 212 and aligned along the ports axes 214. Accordingly, exhaust gasses traversing the brick compartment 200 will be directed from the entry port 210 through the aftertreatment bricks 150 along the port axis 214 to the exit port 212.
To secure the aftertreatment bricks 150 in their intended location inside the brick compartment 200, a releasable securing assembly may be provided. Referring to
To accommodate the aftertreatment brick 150, the first and second brackets 222, 224 can include surfaces shaped to be complementary with the periphery of the aftertreatment brick. Specifically, the first bracket 222 can include a first surface 230 designed to fit about a portion of the aftertreatment brick and the second bracket 224 can include a second surface 232 designed to fit about another portion of the periphery of the brick. In the illustrated embodiments, where the aftertreatment brick 150 is cylindrical in shape, the first bracket 222 may have a semi-annular shape and the first surface 230 may be curved to correspond to the periphery of the brick. The second bracket 224 can similarly have a semi-annular shape and the second surface 232 can be curved to correspond to the cylindrical shape of the brick. In the specific embodiment illustrated, the first bracket can be formed from a thin rectangular plate of metal that is curved into the semi-annular shape, but in other embodiments could have additional features or framework that positions the lower bracket in the brick compartment with respect to the port. In addition, the second bracket 224 can include a mounting flange 236 extending perpendicularly from the semi-annular shape and, more particularly, extends from a curved edge of the second surface 232 to be flush with the front or rear walls 202, 204 of the brick compartment 200. The mounting flange 236 may include holes or apertures that can accommodate fasteners 238 such as bolts to fix the flange to the wall. In the illustrated embodiment, the first bracket 222 and the second brackets 224 may each extend approximately around half the circumference of the cylindrical aftertreatment brick but, in other embodiments, the degrees of extension may vary. The radius of the curved first and second surface 230, 232 may correspond to the diameter of the aftertreatment brick. In other embodiments, the aftertreatment bricks and brackets may have different complementary shapes.
The band clamp 226 can include an elongated, semi-flexible strap 240 of metal or other suitable material with fasteners or clips 242 disposed at either end that can interlock together to fasten the ends together in a loop. The clips 242 may be configured so that the length and/or diameter of the band clamp 226 are adjustable. Any suitable adjustment mechanism can be used including, for example, ratchets, cooperative screw threads and grooves, threaded rods and nuts, and the like. The band clamp 226 may extend around the exterior of the first and second brackets 222, 224 and can be tightened to secure and possibly compress the brackets around the cylindrical periphery of the aftertreatment brick 150. The band clamp 226 may be positioned so that the clips 242 are oriented along the upper second bracket 224 and towards the hatch for ease of access.
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The locations and dimensions of the steps 248 on the brackets and the ribs 199 on the aftertreatment brick 150 can be arranged so that the first rim 192 of the mantle 190 of the aftertreatment brick is moved into abutting contact with the wall 210, 212 of the brick compartment. To achieve this, a first axial distance indicated by arrow 260 between the step 248 and the inside surface of the compartment wall 210, 212, when the first bracket 222 is attached thereto and a second axial distance indicated by arrow 262 between the rib 199 and the first rim 192 of the aftertreatment brick 150 can be correlated. Specifically, the second axial distance 262 is slightly smaller than the first axial distance 260 so that the steps 248 are positioned at the side of the rib 199 opposite the orientation of the compartment wall 210, 212, as described above, and urge the aftertreatment brick 150 against the compartment wall. Contact between the first rim 192 of the mantle 190 and the compartment walls 210, 212 may form a seal between the aftertreatment brick and the entry or exit ports 210, 212 preventing leakage of the exhaust gasses and assist in directing exhaust gasses through the bricks.
At this point, to releasably secure the second bracket 224 to the inside of the brick compartment in a manner that completes the assembly of the aftertreatment brick and first and second brackets inside the brick compartment, the fasteners 238 can be inserted through holes in the mounting flange 236 of the second bracket and threaded to the compartment wall. In an embodiment, to receive the fasteners 238, a threaded nut or boss 252 may be disposed on the opposite side of the compartment wall 210, 212. The aftertreatment brick 150 is thereby releasably secured in a substantially leak free manner proximate the respective entry or exit ports 210, 212
The present disclosure is applicable to the installation and servicing of aftertreatment bricks in an aftertreatment system for treating exhaust gasses, which may be beneficial if the bricks become damaged or depleted. Referring to
Because the aftertreatment brick 150 is no longer vertically constrained by the second bracket 224 and the band clamp 226 has been axially displaced with respect to the first bracket 222, the aftertreatment brick can also be removed through the open hatch 206. The same aftertreatment brick can be serviced and reinstalled, or a new aftertreatment brick can be installed, by reversing the foregoing process. The same first bracket, second bracket and band clamps can be reused. If necessary, the operator can sever the low cost fasteners 238 if they have become corroded by galling or the like during the removal process and replace them with the new fasteners. Referring to
It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.
The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context.
Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.