WO2007058701A1

WO2007058701A1 - Exhaust treatment device with condensate gate

Info

Publication number: WO2007058701A1
Application number: PCT/US2006/036726
Authority: WO
Inventors: David M. Thaler
Original assignee: Caterpillar Inc.
Priority date: 2005-11-21
Filing date: 2006-09-20
Publication date: 2007-05-24
Also published as: FI20085594A; US20070113547A1; DE112006003148T5

Abstract

A method and apparatus for treating fluid are provided. The fluid treatment device (10) may include a housing (14) having a fluid treatment element (18) therein. The device may further include at least one of (i) an inlet channel (34) coupled to the housing and configured to direct fluid toward the fluid treatment element and (ii) an outlet channel (42) coupled to the housing and configured to direct fluid away from the fluid treatment element. The at least one of the inlet channel and the outlet channel may include a shell member (54) having an inner diameter and defining a fluid passage (46). The at least one of the inlet channel and the outlet channel may further include a gate member (50) coupled to and arranged at least partially within the shell member and extending longitudinally from a first gate member portion (50a) having a diameter less than the inner diameter of the shell member to a second gate member portion (50b) having a diameter greater than the inner diameter of the shell member.

Description

EXHAUST TREATMENT DEVICE WITH CONDENSATE GATE

Technical Field

This disclosure relates generally to a method and apparatus for treating gases and, more particularly, to a method and apparatus for treating exhaust gases from an engine.

Background

A diesel particulate filter (DPF) is a fluid treatment device that is commonly arranged within an exhaust gas stream of an internal combustion engine to trap particulates present in the exhaust gas. A DPF may include a cylindrical metal housing wrapped around a cylindrical ceramic filter element. A resilient mat may be compressed between the outer wall of the filter element and the inner wall of the metal housing. Because the mat is resilient and is compressed around the filter element by the housing wall, the mat may help secure the filter element within the housing while reducing vibratory effects between the housing and the filter.

A mat's effectiveness in securing a filter element within a housing may partly depend on the mat's ability to exert pressure on the filter element. The mat's exertion capacity may be decreased if the mat deteriorates or if the mat is exposed to undesirable conditions for a period of time. For example, if a mat is exposed to excessive moisture for a prolonged period, the mat's capacity to exert a holding pressure on a filter may be temporarily or permanently relaxed. Thus, it may be helpful to prevent a mat's overexposure to moisture within a DPF.

During operation of an internal combustion engine attached to a DPF, hot exhaust gases from the engine cause components within the DPF to heat up. When the engine is shut down, the DPF components cool, and condensation may occur on surfaces of the DPF components. This condensation, if allowed to pool around a mat, may adversely affect the mat's characteristics, as referenced above.

Various devices have been proposed for reducing a mat's exposure to moisture within a DPF. For example, in one such device, a cylindrical particulate filter is wrapped with a mat, and a sheet of metal is wrapped around the filter and mat to form a cylindrical metal housing. The cylindrical housing has a first outer diameter along most of its length. A longitudinal end of the cylindrical housing has a slightly decreased outer diameter with respect to the first outer diameter. The cylindrical housing is then tightly wrapped with a second, relatively longer piece of metal to form a second, longer cylindrical housing. A condensate catch volume is defined inside the second housing between the inner wall of the second housing and the outer wall of the first housing at the region of the first housing having a slightly decreased diameter. The DPF is then arranged in a vertical orientation so that the condensate catch volume faces upward. During operation, exhaust gas from an internal combustion engine is directed into a lower longitudinal end of the DPF and is exhausted from an upper longitudinal end of the DPF. When the engine is shut down, components within the DPF cool, and condensation is formed on the interior wall of the second housing. When the condensation drips down this wall, it is directed toward and held within the condensate catch volume rather than directly into the first housing (where the mat is arranged).

Exhaust treatment devices may be improved, for example by providing alternative, robust devices and methods for preventing or reducing moisture exposure within the devices.

The present invention is directed to overcome or improve one or more disadvantages associated with prior apparatus and methods for treating gases. Summary of the Invention

In one aspect of the present invention, a fluid treatment device is disclosed. The fluid treatment device may include a housing having a fluid treatment element therein. The device may further include at least one of (i) an inlet channel coupled to the housing and configured to direct fluid toward the fluid treatment element and (ii) an outlet channel coupled to the housing and configured to direct fluid away from the fluid treatment element. The at least one of the inlet channel and the outlet channel may include a shell member having an inner diameter and defining a fluid passage. The at least one of the inlet channel and the outlet channel may further include a gate member coupled to and arranged at least partially within the shell member and extending longitudinally from a first gate member portion having a diameter less than the inner diameter of the shell member to a second gate member portion having a diameter greater than the inner diameter of the shell member. . In another aspect of the present invention, a method of assembling a fluid treatment apparatus is disclosed. The method may include inserting a gate member at least partially into a fluid passage of a shell member having an inner diameter so that (i) a first portion of the gate member having a diameter less than the inner diameter of the shell member is arranged within the shell member and (ii) a second portion of the gate member having a diameter greater than the inner diameter of the shell member is arranged outside the shell member. The method may further include coupling the shell member to a housing having a fluid treatment element therein so that the shell member is configured to direct a flow of fluid toward or away from the fluid treatment element. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. Brief Description of the Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments or features of the invention and, together with the description, serve to explain principles of the invention. In the drawings,

Fig. l is a front cross-sectional view of a fluid treatment device;

Fig. 2 is a partial front cross-sectional view of the fluid treatment device of Fig. 1; and

Fig. 3 is a partial front cross-sectional view of the fluid treatment device of Fig. 1.

Although the drawings depict exemplary embodiments or features of the present invention, the drawings are not necessarily to scale, and certain features may be exaggerated in order to better illustrate and explain the present invention. The exemplifications set out herein illustrate exemplary embodiments or features of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

Detailed Description

Reference will now be made in detail to embodiments or features of the invention, examples of which are illustrated in the accompanying drawings. Generally, the same or corresponding reference numbers will be used throughout the drawings to refer to the same or corresponding parts.

Referring now to Fig. 1, a fluid treatment device 10 for treating fluid is shown. More particularly, Fig. 1 shows a diesel particular filter (DPF) 10 for treating exhaust gas from an engine. It should be appreciated that while a DPF is shown in the drawings and described herein for explanatory purposes, other types of fluid treatment devices 10 may be used in accordance with this disclosure. For example, various devices having fluid treatment elements, such as substrates, may be used. The DPF 10 may include an element housing 14, a fluid treatment element 18 arranged within the housing 14, a mat 22 arranged between the housing 14 and the fluid treatment element 18, and inlet and outlet channels, such as inlet and outlet portions 34, 42, configured to permit fluid flow toward and away from the fluid treatment element 18, respectively.

The housing 14 may form a metallic shell for the DPF 10 for receiving a stream of engine exhaust gas from an exhaust pipe 38 via the exhaust inlet portion 34. The gas is directed from the inlet portion 34 through the fluid treatment element 18, and out of the DPF 10 via the exhaust outlet portion 42. The housing 14 may be formed into a generally cylindrical shape and may be made from a suitable metallic material, such as steel, for handling hot exhaust gases.

The fluid treatment element 18 may be an exhaust treatment element 18, such as a cylindrical ceramic substrate for treating exhaust gas from an engine. For example, as discussed earlier, a ceramic substrate 18 may be used to remove particulates from a stream of engine exhaust gas.

A mat 22 may be arranged between the housing 14 and the fluid treatment element 18. For example, the mat 22 may be formed from a resilient material and may be compressed to a predetermined amount between an inner surface of the housing 14 and an outer surface of the fluid treatment element 18. The mat 22 may take the form of a single piece of material covering a substantial portion of the outer surface of the fluid treatment 18 (as shown in Fig. 1). However, it should be appreciated that, alternatively, the mat may take other forms, such as one or more relatively smaller strips of material, each covering a relatively small portion of the outer surface of the fluid treatment element 18. The mat 22 may be formed from an intumescent material, a non-intumescent material, or a combination material having intumescent and non-intumescent properties, and may also function as a heat and/or vibration insulator between the fluid treatment element 18 and the housing 14. In one embodiment, the mat 22 may be formed at least in part from alumina-silicate cloth.

Referring now to Fig. 2, the inlet portion 34 may form a fluid passage 46. The inlet portion 34 may include first and second shell members 54, 58, and insulating material 62 arranged between the first and second shell members 54, 58.

In one embodiment, the first shell member 54 may be formed from a sheet of metal arranged to form a generally cylindrical cavity 59 having an inner diameter Dl . An additional piece of material 60 (e.g., steel) may be sealingly attached to one end of the shell member 54. An opening 60a may be formed in the piece of material 60 to permit insertion of the exhaust pipe 38 into the cavity 59.

The second shell member 58 may similarly be formed from a sheet of metal arranged to form a generally cylindrical cavity 63 having an inner diameter D2. The second shell member 58 may be arranged around the first shell member such that an internal cavity 66 is formed between the first and second shell members 54, 58. An additional piece of material 65 (e.g., steel) may be sealingly attached to one end of the second shell member 58. An opening 65a may be formed in the piece of material 65 to permit insertion of the exhaust pipe 38 into the cavity 59. As referenced above, insulating material 62 may be held within the cavity 66 and within a cavity 67 formed between the two pieces of material 60, 65. Spacing elements 69, such as clips 69, may be arranged between the first and second shell members 54, 58 and between the pieces of material 60, 65 to maintained desired spaced relationships therebetween. A gate member 50 may be configured at least partially within the fluid passage 46 of the inlet portion 34 for at least inhibiting flow of condensed fluid within the fluid treatment device 10. In the embodiment of Figs. 1 and 2, the gate member 50 is a generally frustoconical member arranged partially within the first shell member 54. The gate member 50 extends longitudinally from a first gate member portion 50a having an outer diameter D3 less than the inner diameter Dl of the first shell member 54 to a second gate member portion 50b with an outer diameter D4 greater than the inner diameter Dl of the first shell member 54. The first gate member portion 50a is arranged within the fluid passage 46 of the first shell member 54, while the second gate member portion 50b is arranged outside the fluid passage 46 of the first shell member 54 and inside the second shell member 58.

The gate member 50 may extend from the first gate member portion 50a into sealing engagement with the first shell member 54, for example at an exterior surface location 70 on gate member 50 between the first and second gate member portions 50a, 50b. In one embodiment, the gate member 50 is welded to the first shell member 54 at location 70 (Fig. 2) about all or substantially all of the circumference of gate member 50. Thus, a fluid volume 74 may be defined within the first shell member 54 between an outer surface of the gate member 50 and an inner surface of the first shell member 54. It should be appreciated that the gate member 50 may alternatively be welded to the first shell member 54 at various locations about the circumference of the gate member 50.

The gate member 50 may also be coupled to the second shell member 58. For example, the gate member 50 and the second shell member 58 may be welded together, for example at or proximate an end location 78 (Fig. 2) of gate member 50, either about all or substantially all of the entire circumference of the gate member 50 or at various locations thereon.

In the embodiment of Fig. 2, the gate member 50 extends from outside of the first shell member 54 into an opening 82 of the first shell member 54 and extends into the first shell member 54 a distance D5 from the opening 82.

The gate member 50 may be configured to extend into the fluid passage 46 a predetermined radial distance D7 away from the first shell member 54. For example, the outer diameter D4 of the gate member portion 50a may be smaller than the inner diameter Dl of the first shell member 54 by a value of twice the distance D7.

As illustrated in Fig. 3, the outlet portion 38 may be configured generally the same as the inlet portion 34. The first and second shell members 54', 58' of the outlet portion

38 may each have an aperture 86' therein configured for permitting fluid (e.g., condensation) egress from within the first shell member 54' and the outlet portion 38. A tube 90' may be inserted through the apertures 86' for transmitting the fluid out of the outlet portion 38. In the embodiment of Fig. 3, the aperture 86' in the first shell member 54' is arranged within the first shell member 54' at least partially within a distance D6' from the opening 82'. The distance D6' may, in one embodiment, be less than or equal to the distance D5' so that if the fluid treatment device 10 is arranged in a vertical orientation and the outlet portion 38 is arranged atop the housing 14, if condensate becomes held within the fluid volume 74', the condensate may drain from the outlet section 38 via the tube 90'.

Industrial Applicability

In an assembly operation, the fluid treatment element 18 may be wrapped with the mat 22 and the housing 14. The fluid inlet portion 34 for carrying fluid toward the fluid treatment element 18 and the fluid outlet portion 38 for carrying fluid away from the fluid treatment element 18 may each be assembled by inserting the frustoconical gate member 50 partially into the fluid passage 46 formed by the first shell member 54. The first gate member portion 50a may be arranged within the first shell member 54, and the second gate member portion 50b may be arranged outside the first shell member 54. The gate member 50 may then be coupled to the first shell member 54, for example via a welding process as referenced above. The welding process may form a weld around the outer surface of gate member 50 and the end, or an outer surface of, the first shell member 54. After insulating material 62 and clips 69 are placed around the outer surface of the first shell member 54, the second shell member 58 may be arranged about the first shell member 54 and the gate member 50. The gate member 50 then may be coupled to the second shell member 58, for example via a welding process as referenced above. The welding process may form a weld around the end of, or around an inner surface of, gate member 50 and the end of, or an inner surface of, second shell member 58. As shown in Fig. 2, the second shell member 58 may be arranged about the first shell member 54 and the gate member 50 such that a frustoconical portion of the gate member 50 extending from within the first shell member 54 to a position outside of the first shell member 54 extends within the second shell member 58. As shown in Fig. 2, the second shell member 58 may extend beyond the longitudinal end of gate member portion 50b, for example a predetermined distance D8. This extension of the second shell member 58 beyond the edge of gate member portion 50b may facilitate a welding process during which the gate member 50 is coupled to the second shell member 58. It should be appreciated that the distance D8 may be minimized or reduced to substantially zero in order to place the filter-side end of the gate member 50 as close as possible to the joint between the inlet / outlet portion 34 / 38 and the housing 14, filter 18, and mat 22 to better protect the mat 22 from condensate formed on most surface area in the inlet / outlet portion 34 / 38.

The inlet and outlet portions 34, 38 of the device 10 may be coupled to the housing 14, for example via a clamping operation during which each of the inlet and outlet portions 34, 38 is placed adjacent the housing 14 and a clamping element 94 is arranged about each of the portions 34, 38 to hold each of the portions 34, 38 together with the housing 14. In the embodiment of Fig. 1, portions 34, 38 and housing 14 each contain mating flanges 98, 102, around which a clamping element 94 may be arranged. It should be appreciated that one or more seals or gaskets may be arranged between the clamped components for sealing the junctions therebetween.

It should further be appreciated that the inlet and outlet portions

34, 38 may be arranged so that a larger diameter portion 50b of the gate member 50 may be arranged toward the filter element 18, while a smaller diameter portion

50a of the gate member 50 may be arranged relatively away from the filter element 18.

During operation of the fluid treatment device 10, hot engine exhaust may be transmitted through the device 10 (for example via exhaust pipes 38, 38'), and the components thereof may be heated. When the engine is shut off, the components of the device 10 may cool, and condensate may form on them.

The gate member 50 may operate to prevent or at least inhibit the condensate 50 from flowing toward the mat 18 within the housing 14. For example, if the device 10 is arranged in a horizontal configuration (as shown in Figs. 1-3), condensate may gather in the fluid volume 74 and may pool between the gate member 50 and the piece of material 60 at the rear of the cavity 59, rather than flowing from the inlet portion 54 into the housing 14 and toward the mat 22.

If the device 10 is arranged in a vertical configuration, condensate may still flow into and gather in the fluid volume 74, 74' rather than flowing from the inlet or outlet portion 54, 58 (whichever is placed atop the filter element

18) into the housing 14 and toward the mat 22.

It should be appreciated that the orientation and form of the gate members 50 may facilitate holding condensate away from the filter element 18 and mat 22 during start up of an engine until the system heats up enough to evaporate the condensate. Moreover, the forms (e.g., the frustoconical aspects thereof) of the gate members 50 disclosed herein may facilitate relatively smooth exhaust flow transitions into and out of the filter element housing 14 during operation of the device 10. -l i¬

lt should further be appreciated that since a gate member 50 may be attached to an inlet portion 34 or an outlet portion 38, each of which may be detachable from the element housing 14, each gate member 50 may be detached from the main housing 14 and adjusted, replaced, or maintained without having to work directly on the fluid treatment housing 14.

From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit or scope of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and figures and practice of the invention disclosed herein. It is intended that the specification and disclosed examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims and their equivalents. Accordingly, the invention is not limited except as by the appended claims.

Claims

1. An apparatus for treating fluid, comprising: a housing (14) having a fluid treatment element (18) therein; at least one of (i) an inlet channel (34) coupled to the housing and configured to direct fluid toward the fluid treatment element and (ii) an outlet channel (42) coupled to the housing and configured to direct fluid away from the fluid treatment element; wherein at least one of the inlet channel and the outlet channel includes: a shell member (54) having an inner diameter and defining a fluid passage (46); a gate member (50) coupled to and arranged at least partially within the shell member and extending longitudinally from a first gate member portion (50a) having a diameter less than the inner diameter of the shell member to a second gate member portion (50b) having a diameter greater than the inner diameter of the shell member.

2. The apparatus of claim 1, wherein at least a portion of the gate member has a frustoconical form.

3. The apparatus of claim 2, wherein the frustoconical form of the gate member extends from the first gate member portion to the second gate member portion.

4. The apparatus of claim 1, wherein: the gate member extends from the first gate member portion toward and into engagement with the shell member; and a fluid volume (74) is defined within the shell member between the gate member and an internal wall of the shell member.

5. The apparatus of claim 4, wherein: the gate member extends from the first gate member portion toward and into sealing engagement with the shell member.

6. The apparatus of claim 1, wherein: the shell member is a first shell member; and the apparatus includes a second shell member (58) arranged at least partially about the first shell member.

7. The apparatus of claim 6, wherein the gate member is coupled to the first shell member and the second shell member.

8. The apparatus of claim 6, wherein a frustoconical portion of the gate member engages the first shell member and the second shell member.

9. The apparatus of claim 1, wherein the fluid treatment element is an exhaust treatment element for treating exhaust gas from an engine.

10. The apparatus of claim 1 , wherein the gate member is configured for at least inhibiting a flow of condensed fluid within the apparatus toward the fluid treatment device.

11. A method of assembling a fluid treatment apparatus, the method comprising: arranging an annular gate member (50), having a generally frustoconical portion, at least partially within a fluid passage (46) of a shell member (54); then coupling the shell member to a housing (14) having a fluid treatment element (18) therein so that the shell member is configured to direct a flow of fluid toward or away from the fluid treatment element.

12. The method of claim 11 , wherein the step of arranging an annular gate member at least partially within a fluid passage of a shell member includes coupling the gate member to the shell member.

13. The method of claim 11 , wherein: the shell member is a first shell member; and the method includes arranging a second shell member (58) at least partially around the first shell member and at least partially around the gate member.

14. The method of claim 13, including coupling the gate member to the second shell member.