WO2012074501A2

WO2012074501A2 - Exhaust stack with baffles

Info

Publication number: WO2012074501A2
Application number: PCT/US2010/054374
Authority: WO
Inventors: Paul F. Olsen
Original assignee: Caterpillar Inc.
Priority date: 2009-12-22
Filing date: 2010-10-28
Publication date: 2012-06-07
Also published as: CN102782276B; US20110151760A1; DE112010004974T5; CN102782276A; WO2012074501A3

Abstract

Art exhaust stack is disclosed for protecting exhaust system components from liquid entering art exhaust stack discharge port-. The exhaust stack includes a first section defining a first flow passage.extending along a first longitudinal axis and a second section having an open end and defining a second flow passage extending along a second longitudinal axis. The exhaust stack further includes a liquid drain disposed in the first section and one or more baffles disposed in the second flow passage, wherein the one or more baffles are; configured to block lihe-of-sight between the open second end and any inner surface. below the liquid drain

Description

Description EXHAUST STACK WITH BAFFLES

Technical Field

The present disclosure relates generally to an exhaust system and, more particularly, to an exhaust system having one or more baffles disposed near the discharge end.

Background

Internal combustion engines, including diesel engines, gasoline, engines, natural gas engines, turbine engines, and other engines known in the art, are used to drive many types of power systems. Exhaust from the internal combustion engines is typically discharged into the atmospherei A power system may include an exhaiist. stack that extends vertically from the engine or from an enclosure of the engine in order.to discharge the exh aust. As such, it is possible for precipitation to enter the, exhaust stack when the engine is non-operational (i.ei, when the exhaiist stack is not being pressurized by a flow of exhaust). When the engine. is operational, . precipitation can also enter the exhaust stack where the exhaust flow is weakest.

Moisture in the exhaust system can damage various exhaust, system components, such as after-treatment devices. For example, diesel particular filters (DPFs) often utilize a ceramic wall- flow substrate. When the engine is non-operational in cold environments, water in the exhaust system may freeze. If in contact with the ceramic substrate, the freezing and expansion of the water may crack the substrate.

To avoid problems wilh moisture, such as precipitation, entering thc cxhaust system via a vertically extending stack, some stacks include protective devices. For example, U.S. Patent 2,630,748 (hereinafterthe '748 patent), by Brockelsby, discloses an exhaust rain protector.. The '748 patent discloses using an adapter that mounts onto.a vertically extending exhaust pipe. The adapter includes a pair of angled baffles that divert any rain water entering, the exhaust discharge etid out a pair of spouts and create maze-like flow path for the exhaust that prevents water from entering the exhaust system past the baffles.

While the device disclosed in the '748 patent may prevent rainwater from entering the exhaust system, it requires fitting an offset, bulky adapter onto the end of the exhaust pipe that increase space and height of the exhaust stack. Furthermore, the device is ill-suited for exhaust stacks already haying an angled discharge end. Still further, the maze-like flow path may result iii an undesirable increase in exhaust back pressure.

The present disclosure is directed to overcoming one or more of the shortcomings ih the existing technology.

Summary of the Disclosure

In accordance with one aspect, the present disclosure is directed an exhaust stack having

a first section defining a first flow passage extending along a first longitudinal axis and a second section haying an open end and defining a second flow passage extending along a second longitudinal axis, The exhaust stack further includes a liquid drain disposed in the first section and one or more baffles disposed in the second flow passage, wherein the one.or more baffles are configured to block I ine-of-sight between the. open second end and any inner surface below the liquid drain.

According to another aspect, the present disclosure is directed toward a method of protecting exhaust system components from liquid entering an exhaust stack. discharge port. The method includes providing a liquid drain along an exhaust flow path in the exhaust stack, blocking lirteof sight between the exhaust stack discharge port and any inner surface of the exhaust system below the liquid drain, and positioning one or more baffles in the exhaust stack such that liquid falling by gravity from the one or more baffles will contact an inner surface of the exhaust stack between the liquid drairi.arid the one of more baffles.

Other features and aspects of this disc losure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings

In the accompanying drawings, which are incorporated in and constitute a part of this specification, exemplary embodiments of the disclosure arc illustrated, which, together with the written description, serve to explain the, principles of the disclosed system:

Fig. 1 is a side cross section illustration of an exemplary power system with a first embodiment of an exhaust stack;

Fig. 2 is a front view of the exhaust stack of Fig. 1 ;

Fig. 3 is a side cross section illustration of an exemplary power system with a second embodiment of an exhaust stack;.and

[0014] Fig. 4 is; a side cross section illustration of another embodiment of a liquid drajn of the exhaust stack.of Fig. 3.

Detailed Description

Referring to Fig. 1 , an exemplary power system 10 is disclosed. The power system 10 may include an engine 12; an exhaust system 1 Ί, and a housing 16. The engine 12 may include feanires not shown, such as fuel systems, air systems^ cooling systems, peripheries, drivetraih components, turbochafgers,, etc. The engine 12 may be any type of engine (infernal combustion, turbine, gas, diesel, gaseous^¾fuel_? natural gas, propane, etc.), may be o f any size^ with any number of cylinders, and in any configuration ("V," in-line, radial, etc.). The engine 12 may be used to power any machine or other device, including locomotive applications, on-highway trucks or vehicles, off-highway trucks or machines, earth moving equipment, generators,, aerospace applications, marine applications, pumps, stationary equipment, or other engine powered applications. The housing 16 may be any structure that encloses or partially encloses the engine 12 and exhaust system 14. For example, the housing 16 may be a vehicle body or hood.

The exhaust system 14 may include an exhaust manifold 18, one or more exhaust aftertreatmerit devices 20 designed to reduce undesirable emissions from the exhaust of the engine 12, and an exhaust stack 22. The exhaust aftertreatment devices 20 may include a variety of emissions treatment technology, including, but not limited to, regeneration devices, heat sources, oxidation catalysts, diesel oxidation catalysts (DOCs), diesel particulate filters (DPFs), selective catalytic reduction catalysts (SCRs), lean NOx traps (LNTs), mufflers, or other devices needed to treat the exiting, the engine 12.

In the depicted embodiment, the exhaust iftertreatment devices 20 include a diesel particulate filter (DPF) 24. The DPF 24 may include a DPF substrate 26 at least partially disposed within a DPF housing 28. The DPF substrate 26 may be configured in a variety of ways. Any structure capable of removing particulate matter from the exhaust of the engine 12- may be. used. For example, the DPF substrate may a wall-flow ceramic structure having a honeycomb, cross-section constructed of cordiefite, silicon carbide, or other material to remove the particulate matter.

The exhaust stack 22 may be configured in a variety of ways. Any structure capable of routing exhaust exiting; the power_;system 1.0 in a desired direction may be used. For example, the cross-sectional shape of the exhaust stack 22 may be circular or may be some other geometric- shape. The exhaust stack 22 may extend substantially vertically upward or may extend at an angle to , vertical. Referring to Fig. 1 , in the first depicted embodiment, the exhaust stack 22 includes a first section 30 defining a first flow passage 31 and a second section 32 defining a second flow passage 33. The first section 30 is configured as a substantially cylindrical tube extending along a first longitudinal axis 34 and having a first inner surface 36. The first section 30 may have a first eiid 38 configured to receive exhaust from the engine 12 and a second end 40 configured to fluidly couple to the second section 32.

The first section 30 may include a liquid drain 42. The liquid drain 42 may be configured in a variety of ways. Any structure capable of collecting or redirecting liquid (such as water) that flows down the first inner surface 36 of the first section 30 may be used. In the depicted embodiment, the liquid drain 42 is configured as an annular trough having a bottom wall 44 disposed between a sidewall 46 and the first inner surface 36. One or more apertures 48 may be formed in the first inner surface 36 adjacent the bottom wall 44. The one or more apertures 48 being configured to transport liquid from the trough (and interior of the stack) to the exterior of the first section 30.

In the depicted embodiment, the second section 32 is configured as a substantially cylindrical tube extending along a second longitudinal axis 49 and having a second inner surface 50. The second longitudinal axis 49 may be disposed at an angle Θ relative to the first longitudinal axis 34. The second section 32 may have a first end 52 fluidly coupled to the second end 40 of the first section 30. The second section 32 may also have an open second end 54 that terminates to form an exhaust stack discharge port. The open second end 54 may terminate in a plane that is substantially parallel with the first longitudinal axis 34.

The second section 32 may include one or more baffles 56 disposed in the second flow passage 33. The number of baffles 56 and the shape, size, and orientation of the baffles may vary. Any structure(s) capable of protecting the exhaust aftertreatment device(s) 20 from water entering the discharge port of the stack may be used. In the depicted embodiment, the four baffles are arranged in the second section 32* though more or less baffles may be used. Each baffle 56 has a generally elongated body having a first end 58 and a second end 60.

The one or more baffles 56 may be arranged generally parallel to the second longitudinal axis 49 {i.e. at an angle Θ to the first longitudinal axis 34) and generally parallel with each other. The second end 60 of each baffle may be generally located proximate the open second end 54 of the second sectidn 32.

Referring to Fig. 2, each the one or more baffles 56 may extend horizontally across the open second end 54 such that exhaust that exits the exhaust stack 22 flows between two adjacent baffles 56 or between a baffle 56 and the second inner surface 50 of the second section 32. Each of the one or more baffles 56 may have one or more, side surfaces 62. The one or more side surfaces 62 may fol low the contour of the second inner surface 62. The one or more baffles 56 may be fixably attached to the second inner surface 50 by any suitable means, such as fasteners or welding. For example, one or'more side surfaces 62 of a baffle 56 may be welded to the inner surface 50 of the section second 32.

Referring to F ig. 1 , the first end 58 of each baffle 56 may be if located a distance D from the edge or intersection between the first section 30 and the second. section 32. Thus, the first end 58 does not extend into or over the first flow passage 3 1 and, as viewed in Figure 1, is over the second inner surface so;

Referring to Fig. 3, a second embodiment of an exemplary exhaust stack is disclosed. The exhaust stack 122 illustrated in Fig. 3, is similar to the exhaust stack 22 of Fig. 1, with the exception of a baffle modification. Thus, the power system 110 of Fig. 3 rnay include an engine 1 12, an exhaust system 114, and a housing ! 16. The exhaust system 1 14 may include an exhaust manifold 1 18, one or more exhaust artertreatment devices 120 and the exhaust stack 122.

The exhaust aftertreatriient devices 120 may include for example, adiesel particulate Filter (DPF) 124 that includes a DPF substrate 126 at least partially disposed within a DPF housing 128.

The exhaust stack 122 may be configured in a variety of ways. Any structure capable of routing exhaust exiting the power system 1 10 in a desired direction may be used. The exhaust stack 122 may extend substantially vertically upward or may extend at an angle to vertical. In the depicted embodiment, the exhaust stack 122 includes a first section 130 defining a first flow passage 131 and a second section 132 defining a second flow passage 133. The first section 130 is configured as a substantially cylindrical tube extending along a firstjongitudinal axis 134 and having a first inner surface; 136. The first section 130 may have a first end 38 configured to receive exhaust from the engine 1 12 and a second end 140 configured to fliiidly couple to the second section 132.

The first section 130 may include a liquid drain 142. The liquid drain 42 may be configured in a variety of ways. Any structure capable of diverting and/or catching liquid (such as water) that flows down the first inner surface 136 may be used. In the depicted embodiment, the liquid drain 142 is configured as an annular trough having a bottom wall 144 disposed between a sidewall 146 and the first inner surface 136; One or more apertures 148 may be formed in the first inner surface 136 adjacent the bottom .wall 144· The one or more apertures 148 being configured to allow liquid to flow from the trough (and interior ofthe stack) to the exterior of the first section 130. Thus, the liquid drain 42 catches and diverts the liquid so that the liquid does not continue to flow down the interior ofthe pipe.

Referring to F igure 4, in another embodiment of the. liquid drain, the first section 230 may include an upper portion 232 and a lower portion 234. The lower portion 234 includes ah inward flared inlet or venturi ihlet:236 that at least partially is received within the upper portion 232. One or more apertures 238 may be formed between the upper portion 232 and the lower portion 234 to form a liquid drain 242. Thus, liquid that flows down the inner surface of the upper portion 232 will not.enter the flared inlet 236 Of the lower portion 234 and will be diverted to the exterior of the stack. In another embodiment, one or more baffles (not shown) may be positioned proximate the inlet 236 to further divert any liquid away from entering the inlet 236.

.In the depicted embodiment, the second section 132 is configured as a substantially cylindrical tube extending along a second longitudinal axis 138 and having a second inner surface 150. The second longitudinal axis 138 may be disposed at an angle Θ relative to the first longitudinal axis 134. The second section 132 may have a first end 152 fluidly coupled to the second end 140 of. the first section 130. The second section 132 may also have an open second end 154 that terminates to form an exhaust discharge port. The open second end 154 may terminate in a pjane that is substantially parallel with the first longitudinal axis 134,

The second section 132 may include one or more baffles 156 d isposed in the second flow passage 133. The number of baffles 156 and the shape, size, and orientation of the baffles may vary. Any structure(s) capable Of protecting the exhaust aftertreatmerit device(s) 120 from water entering the discharge port of the stack may be used. In the depicted embodiment, the two baffles are arranged in the second section 132, though more or less baffles may be used. Each baffle 156 has a generally elongated. body having a first end 158 and a second end 160. The one or more baffles 156 may be arranged generally parallel with each other. In the depicted embodiment, the two baffles 1 56 are not parallel to the second longitudinal axis 138. In other embodiments, however, the battles 156 may be parallel with the second longitudinal axis 138.

Each of the baffles 156 may include a. lip 166 extending outward at an angle from the second end 160. In the depicted embodiment, the lip 166 extends in a generally perpendicular direction from the baffle 156. The lip 166 may be configured to collect arid channel any liquid on the baffle 156 to the second inner surface 150.

Unlike the embodiment of Fig.1 , the 'second end 160 of each baffle 156 may extend into or over the first flow passage 131.

Industrial Applicability

The disclosed exhaust stack may be applicable to any power system 10 such as for example an engine, a furnace or any other power source know in the art where precipitation may enter (he exhaust stack and cause damage to the exhaust system .components, including ; exhaust after treatment devices. The disclosed exhaust stack may prevent water, which may enter the discharge port of the exhaust stack, from making contact with an exhaust aftertreatment device in the exhaust system, such as a DPF substrate. As a result, the concern of water, in contact with the DPF substrate, rreezing ahd cracking the substrate is eliminated. The operation of exhaust system 14 will now he explained.

Atmospheric air may be drawn into the engine 12, mixed with fuel, and then be combusted to produce mechanical work. Exhaust from the combustion of the air-fuel mixture may contain, gaseous compounds and . solid particulate matter. The exhaust may be directed from engine 12 to the exhaust system 14, arid then directed via the. exhaust stack 22 to an exterior of power system 10.

Since, the open second end 54 of the exhaust stack 22 may be directed upward and open to atrnbsphere,.pfecipitatibn, . sprayed/splashed water or other liquid may enter the exhaust stack 22. and flow downward! toward one or more exhaust aftertreatment devices 20.

The baffles 56, however, may be. configured to. prevent or reduce · the. amount;o,f liquid that may reach the exhaust.aftertreatment de.vice(s) 20. in particular, the one or more baffles 56. may block line_^of^sight between the open second end 54 and any inner surface below thejiquid drain 42. Thus, the trajectory of any liquid that enters, the open second end 54 and does not contact any of the one or more baffles 56 will direct the liquid onto the first inner surface 36 or second inner surface'50 above the liquid drain 42. Therefore, the liquid will flow down the first inner surface 36, be collected by the liquid drain 42; and redirected to the exterior of the exhaust stack 22 via .the one.or more apertures 48 before reaching the DPF substrate 26, for example.

In addition, in the exemplary embodiment of Fig. 1 , the first end 58 of each of the one or more baffles 56 does not extend into or over the first flow passage 3 1. Thus, any liquid that contacts the one or more baffles.56 Will flow off of the first end 58 of each baffle 56 and fall, by gravity, onto the second inner surface 50. Once on the second inner surface 50, the liquid will flow down the first inner surface 36, be collected by the liquid drain 42, and redirected to'the exterior of the exhaust stack 22.

.In the exemplary embodiment of Fig. 3, any liquid that contacts the one or more baffles 156, will flow to the lip 1.66 and be channeled to the. second inner surface 150. Once on the second inner surface 50, the liquid will flow down the first inner surface 36, be collected by the liquid drain 42, and redirected to the exterior of the exhaust stack 22.

Thus, the exhaust stack 22 provides protection'to exhaust system components from liquid entering the stack. Furthermore, since the one or more baffles.may be angled in=lien with the flow of exhaust exiting the stack, the baffles providing minimal increase in exhaust back pressure.

It will be apparent to those skilled in the ait that various modifications and variations can be made to the; disclosed dosing system. Other embodiments wi ll be apparent to those skilled in . the art from consideration of the specification and practice of the disclosed method and apparatus. It is intended - that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.

Claims

1. An exhaust stack (22), comprising:

a first section (30) defining a first flow passage (31) extending along a first longitudinal axis (34);

a second section (32) defining a second flow passage.(33) extending along a second longitudinal axis (49), the second flow passage (33) in fluid communication with the first flow passage (31 ), the second longitudinal axis (49) extending at an angle to the first.longitudinal axis (3.4)* the second section (32) having an open end (54);

a liquid drain (42) disposed in the first section (30); and

one or more baffles (56) disposed in the second flow passage (33), wherein the one or more baffles (56) are configured to block line-qfcsight between the Open end (54) and any inner surface below the liquid drain (42).

2. The exhaust stack (22) of claim 1 wherein the liquid drain (42) extends around a circumference of an inner surface_, (36) of the.first section (30),

3. The exhaust stack (22) of claim 2 wherein the liquid drain (42) includes an aperture (48) configured to direct liquid frorri the liquid drain (42) to an exterior surface of the first section (30).

4. The exhaust stack (22) of claim 1 wherein the one or more of baffles (56) do not extend over the first flow passage (31 ).

5. The exhaust stac k (22) of claim 1 where in the one or more of baffles (56) include a plurality of baffles that are substantially parallel to each other.

6. The exhaust stack (22) of claim 1 wherein the one or more baffles (56) extend in a direction substantially parallel lo the second longitudinal axis (49).

7. The exhaust stack (22) of claim 1 wherein the one or more baffles (56) arc configured such that liquid falling by gravity from the one or more baffles (56) will contact an inner surface of the exhaust stack (22) between the liquid drain (42) and the one or more baffles (56).

8. The exhaust stack (22) of claim 1 wherein the one or more baffles (5,6) include a body portion and a lip (166) extending from the body portion, the lip; (166) configured to route liquid to an inner surface of the exhaust stack (22) between the liquid drain (42) and the one or more baffles (56).

9. A method of protecting exhaust system components from l iquid entering an exhaust stack discharge port, comprising:

providihg a liquid drain(42) along an exhaust flow path (31) in the exhaust stack (22);

blocking line-of sight between the exhaust stack discharge port (54) and any inner surface of the exhaust System below the liquid drain (42); positioning one or more baffles (56) in the exhaust stack (22) such that liquid failing by gravity from the one or more baffles (56) will contact an . inner surface of the exhauststack (22) between the liquid drain (42) and the one or more baffles (56).

1 0. The method of claim 19 further cpmprising.collecting liquid that flows down the inner surface of the exhaust stack (22) and transporting the collected liquid to an exterior of the exhaust stack (22).