Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Waste gas purifier
Patent
1996-02-13
1998-04-14
Tran, Hien
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Waste gas purifier
422170, 422171, 422180, 422211, 422222, 502527, B01D 5334
Patent
active
057388334
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention generally relates to a metal support suitable for use in an exhaust gas cleaning system of an automotive vehicle for supporting an exhaust gas cleaning catalyst.
More specifically, this invention is concerned with an economical unit-type metallic support which is excellent in properties such as durability and which features, as constituent members of a metallic support, use of unit members (wire arrays)--which are each constructed of a wire frame having both a function as a casing and a wire-holding function and wires mounted
BACKGROUND ART
Known catalyst supports of the above-described sort include two types, one being the ceramic-made monolithic type (ceramic monoliths) and the other the metal-made monolithic type (metallic monoliths).
Especially in recent days, a great deal of research and development work has been concentrated on metallic monoliths with a view of improving drawbacks encountered with ceramic monoliths, in other words, from the viewpoints of mechanical strength, durability, flow resistance, cleaning efficiency (the size reduction of a system) and the like.
Conventional metal-made catalyst supports of this type (metallic supports) (MS', metallic supports") are illustrated in FIG. 10 and FIG. 11. A metallic support of this type is constructed of a metal-made honeycomb structure H (hereinafter called a "metal-made honeycomb body" or simply a "honeycomb body") and a cylindrical metal-made casing 4 opening at opposite ends thereof and fixedly enclosing the honeycomb body H therein. In general, the honeycomb body has been fabricated by stacking a planar band 1, which is made of a steel sheet excellent in high-temperature oxidation resistance and heat resistance, and a corrugated band 2, which has been formed by corrugating a similar steel sheet, one over the other in a mutually contiguous relation and then rolling them together into a spiral form or by stacking such planar bands and corrugated bands into a multilayered form, so that the honeycomb body defines a number of network-patterned gas flow passages 3 (hereinafter called "cells") for permitting axial passage of exhaust gas therethrough.
Incidentally, FIG. 10 illustrates the rolled metallic honeycomb body H while FIG. 11 depicts the stacked metallic honeycomb body H.
The honeycomb body and the metal-made casing, which make up the above-described metallic support, are then firmly fixedly together by brazing or welding so that they can withstand thermal expansions and thermal stresses--which occur due to the high temperature of exhaust gas itself and an exothermic reaction of the exhaust gas by the cleaning catalyst (a catalyst formed of Pt, Pd, Rh and the like)--and also vibrations during running of the automotive vehicle. Needless to say, the planar band(s) and the corrugated band(s), which form the honeycomb body, are also fixed together at points or areas of contact therebetween by one of various methods.
As the planar band(s) 1 and the corrugated band(s) 2 in each of the above-described conventional honeycomb bodies, it is possible to use bands (sheets) having a thickness not greater than 0.1 mm and made of a material such as a heat-resistant stainless steel, e.g., chromium steel (chromium content: 13-25%) or Fe-20% Cr-5% Al, or a stainless steel formed by adding one or more rare earth metals to the former stainless steel to improve the high-temperature oxidation resistance. An Al-containing steel band is an extremely preferred material as each band, because it is equipped with improved high-temperature oxidation resistance and, when subjected to heat treatment, .alpha.-Al.sub.2 O.sub.3 is caused to deposit in various forms such as whisker and mushroom forms on its surfaces and serves to firmly hold a wash coat for carrying the exhaust gas cleaning catalyst.
The planar band(s) 1 and corrugated band(s) 2, which make up the metal-made honeycomb body H, are extremely costly because their material itself is expensive and a rolling cost is needed to form the material into sheets (thickness: 0.04-0.1 mm) s
REFERENCES:
patent: 3362783 (1968-01-01), Leak
patent: 4282186 (1981-08-01), Nonnenmann et al.
patent: 4843815 (1989-07-01), Smojver
Tran Hien
Usui Kokusai Sangyo Kaisha Ltd.
LandOfFree
Unit-type metallic support does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Unit-type metallic support, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Unit-type metallic support will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-632514