Gas separation – Combined or convertible – In motor vehicle
Reexamination Certificate
1999-06-17
2001-12-04
Simmons, David A. (Department: 1724)
Gas separation
Combined or convertible
In motor vehicle
C055S322000, C055S446000, C055S466000, C055SDIG003, C422S171000, C422S177000, C422S180000
Reexamination Certificate
active
06325834
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to exhaust gas filters, and more particularly to particulate matter collection and catalytic conversion structures useful in trapping the particulates and fumes of combustion emitted by a diesel power plant.
2. Description of the Prior Art
Diesel engines are characteristically very effective producers of power, primarily because of the high pressures and temperatures of combustion process thereof. While under ideal conditions the power efficiency of the diesel cycle is an attractive feature, in practice the process is infested with numerous faults. For example, once some wear has occurred and the ideal design conditions of combustion are no longer in place, the process becomes quite dirty with large by-products of incomplete combustion and particulates emitted. Those traveling the nation's highways will therefore be familiar with the dark exhaust plumes typically produced by a diesel powered truck. In fact it is the presence of these dark plumes that distinguishes the power plant.
In the recent past the foregoing pollution producing attributes of diesel power have had some attention in the rulemaking process of the US Environmenal Protection Agency [EPA] and heavy vehicles on our highways will therefore be regulated in their exhaust output by the year 2004. This regulatory impetus, along with the earlier concerns over the diesel exhaust, have focused public attention and techniques for trapping and collecting diesel exhaust products are now extensively sought. Exemplary teachings of such mechanisms can be found in U.S. Pat. Nos. 4,183,896 to Gordon; 3,946,748 to Frankfurt; and 4,852,349 to Abthoff et al. While suitable for the purposes intended each of the foregoing teachings either solves the pollution problem by mechanical traps or filters, or by chemical or catalytic processes. The synergistic benefits of a combination of both techniques have had little attention.
Catalytic processes typically rely on expensive material structures, such as platinum, and for that reason the catalyst is a significant cost component of any exhaust treating device. As a consequence techniques that either prolong the useful life of the catalyst, or allow for its convenient cleaning, are an economic necessity in any drive for cleaner exhaust. One factor inherent in the life of the catalyst is the accumulation of soot and condensate on the catalyst surfaces, a problem that is particularly exacerbated in a diesel process. Techniques that trap, reduce and allow for convenient cleaning of this accumulate are therefore desired and it is one such technique that is disclosed herein.
SUMMARY OF THE INVENTION
Accordingly, it is the general purpose and object of the present invention to provide an exhaust particulate accumulator conformed also to cool and condense vapors in the exhaust flow prior to exposure to a catalyst.
Other objects of the invention are to provide a reusable exhaust products collection canister that can be attached to a diesel exhaust.
Further objects of the invention are to provide an exhaust product collection canister which combines the condensation and kinematic processes for optimum reduction of combustion emissions, along with catalytic reactions.
Yet other and further objects of the invention are to provide an emission control device including a catalyst that may be conveniently refurbished by the manufacturer.
Briefly, these and other objects are accomplished within the present invention by providing a generally cylindrical, hollow casing cooled on the exterior by cooling fins and conformed for releasable attachment to the exhaust pipe of a diesel engine. In the first example the casing includes on its interior a series of transverse, perforated and louvered plates that act as kinematic traps and surfaces in the flow of particulate matter from the exhaust pipe. This kinematic exchange reduces the gas temperature of the exhaust flow, thereby promoting condensation of the exhaust vapors and their consequent collection in the form of condensate onto the same louvered plates. The collected condensate then acts as a glue or adhesive to trap additional particulate matter in the exhaust flow.
Accordingly, in the course of use particulate matter is accumulated on the first louvered plates, to form an insulative layer and thereby transfer the heat exchange and condensation functions to the next succeeding plate. Thus the utility period of this collection mechanism can be controlled by the number of plates in the sequence.
This first stage or group of coarse matter collection plates may then be followed by a finer perforation grouping, again in plural repetition, which may take the form as fine metal screening or even fiberglass matting. These fine disks then accumulate the lower temperature vapors and the finer particulate matter, in a manner similar to that earlier described.
A set of spring loaded by-pass vents may be provided to permit flow into exterior manifolds in the event that the collection plates are fully loaded in the course of use. At the same time, the canister may be split and hinged along its length to provide access to the collection plates for cleaning. A simple detergent cleaning process then transfers the collected condensate and particulate matter for proper disposal.
In the second example the benefits of the of the above described particulate filter structure may be used as a prefilter for a third stage including a catalyst, thus limiting the accumulation of debris thereon. The catalyst itself may take the form of a rolled up strip of corrugated metal on which a surface deposit of platinum group metals is accumulated. This tightly wound corrugated roll is then confined between further arcuate retainers along the flow through the housing, allowing for manual unwinding in the course of each cleaning sequence. As a consequence, the catalyst surfaces are protected by the filters, extending their life between cleanings.
While this example is useful with the filter structures described above, in those instances where the catalytic reaction increases the internal temperatures in the housing somewhat coarser filter grid may be used. Thus screen elements of expanded steel, or wire mesh, may provide the necessary collection elements in the exhaust flow, and at the same time are easily cleaned in a washing process. In this manner full reuse of the exhaust assembly is rendered both convenient and effective.
REFERENCES:
patent: 3946748 (1976-03-01), Frankfurt
patent: 4183896 (1980-01-01), Gordon
patent: 4818497 (1989-04-01), Andersson et al.
patent: 4852349 (1989-08-01), Abthoff et al.
patent: 5008086 (1991-04-01), Merry
patent: 5055274 (1991-10-01), Abbott
patent: 5119551 (1992-06-01), Abbott
patent: 5207989 (1993-05-01), MacNeil
patent: 5228891 (1993-07-01), Apiletta
patent: 5447697 (1995-09-01), Ito et al.
patent: 5482681 (1996-01-01), Sager, Jr.
patent: 5618501 (1997-04-01), Wieres et al.
patent: 5672324 (1997-09-01), Okamoto et al.
patent: 5882608 (1999-03-01), Sanocki et al.
patent: 6057263 (2000-05-01), Takahashi et al.
Fonseca Roberto
Paje Rufino A.
Pham Minh-Chau T.
Simmons David A.
Tope - McKay & Associates
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