JPH0570642U - Tandem type metal carrier - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a tandem carrier for increasing the temperature of gas passing through an upper honeycomb body and promoting a catalytic reaction. In a carrier in which two honeycomb bodies are housed in an outer cylinder, a heat insulating layer is provided between an inner peripheral portion and an outer peripheral portion of the upper honeycomb body to form an outer peripheral portion of the upper honeycomb body,
It is possible to prevent heat conduction and dissipation to the outer cylinder part.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a tandem-type metal carrier used for purifying exhaust gas emitted from an automobile engine or the like.

[0002]

[Prior Art]

 As a catalyst carrier for exhaust gas purification, flat foil and corrugated foil of heat-resistant metal foil are alternately laminated and spirally wound, or both foils are alternately laminated to form a honeycomb body. A catalyst carrier has been developed and is already put into practical use. In recent years, in order to further improve the catalyst performance, a tandem carrier in which two honeycomb bodies are brazed and held in one outer cylinder is being used as a catalyst for automobiles, as disclosed in Japanese Utility Model Laid-Open No. 2-4918. That is, in such a tandem carrier, as shown in FIG. 3, the upper honeycomb body 2 and the lower honeycomb body 3 are rigidly joined at the brazing portions 6 and 7 in one outer cylinder 1. When such a metallic catalyst carrier is mounted in the exhaust gas system of an automobile engine, the temperature of the upper honeycomb body 2 rapidly rises due to the small volume of the honeycomb due to the exhaust gas when the engine is started. Dissipation of heat conduction from the joint of the joints also occurs at the same time, which is not desirable.

[0003]

[Problems to be solved by the device]

 If the outer periphery of the upper honeycomb body is joined to the outer cylinder, the heat quantity of the honeycomb body heated by the exhaust gas is deprived to the outer cylinder side, the heating rate is delayed, and the temperature drop after heating is large. However, there is a problem in that the catalyst efficiency becomes low, and the catalyst efficiency is reduced and damage due to thermal stress occurs. Therefore, it is possible to reduce the area where the outer periphery of the upper honeycomb body is in contact with the outer cylinder, but the carrier length of the upper honeycomb body is as short as 10 to 30 mm, and the outer periphery of the upper honeycomb body is in contact with the outer cylinder. There is a problem in that the bonding strength between the upper honeycomb body and the outer periphery becomes insufficient when the area that is covered is reduced.

In order to solve the above problems, the present invention provides a tandem-type metal carrier in which a heat insulating layer is provided in the upper metallic honeycomb body and the temperature rising efficiency of the upper honeycomb body is good.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the gist of the present invention is that two honeycomb bodies formed by stacking flat foils and corrugated foils made of heat-resistant metal and spirally winding or laminating them are made of heat-resistant metal. In a metallic catalyst carrier that is housed and fixed in an outer cylinder, the tandem carrier is characterized by having a heat insulating layer between the inner peripheral portion and the outer peripheral portion of the upper honeycomb body.

That is, when a part of the upper metallic honeycomb body becomes high in temperature, the catalytic reaction of the part proceeds, and the reaction heat raises the temperature of the gas passing through the upper metallic honeycomb body to promote the catalytic reaction. However, a heat insulating layer is provided between the inner peripheral portion and the outer peripheral portion of the upper honeycomb body so that the temperature (heat) of the central portion of the upper honeycomb body does not escape to the outer peripheral portion.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is an example showing the present invention, in which 1 is an outer cylinder, which houses an upper honeycomb body 2 and a lower honeycomb body 3. Reference numeral 4 is a heat insulating layer provided in the upper honeycomb body. As the heat insulating layer material, a heat insulating material such as a ceramic sheet may be used. Reference numeral 6 is a retainer for holding the upper honeycomb body 2 and storing the upper honeycomb body 2 in the outer cylinder 1. FIG. 2 shows a cross section taken along the line AA of the upper honeycomb body in FIG.

That is, conventionally, the outer honeycomb of the upper honeycomb body 2 is in contact with the outer cylinder, so that there is a problem that the heat amount of the heated upper honeycomb body is taken to the outer cylinder side and the temperature rising rate is delayed. The present invention solves the above-mentioned problem that the temperature rising rate is delayed by thermally insulating the central portion 2a of the upper honeycomb body 2 from the outer peripheral portion 2b and the outer cylinder 1 as shown in FIG. The lower honeycomb body 3 and the outer cylinder 1 may be joined by brazing 5 at a part in the axial direction.

[0009]

[Effect of the device]

 According to the tandem carrier of the present invention, it is possible to prevent heat conduction and dissipation between the outer cylinder and the upper honeycomb body, the temperature of the gas passing through the upper honeycomb body rises, the catalytic reaction is promoted, and its effect is extremely high. It's a big one.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a tandem type metal carrier of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory view showing a conventional tandem type metal carrier.

[Explanation of symbols]

 1 Outer Cylinder 2 Upper Honeycomb Body 2a Central Part 2b Outer Part 3 Lower Honeycomb Body 4 Thermal Insulation Layer 5, 7 Brazing Part 6 Retainer

Claims (1)

[Scope of utility model registration request] 1. A metallic material in which two honeycomb bodies formed by stacking a flat foil and a corrugated foil made of a heat-resistant metal and spirally winding or stacking them are housed and fixed in an outer cylinder made of a heat-resistant metal. In the catalyst carrier, a tandem type metal carrier having a heat insulating layer between the inner peripheral portion and the outer peripheral portion of the upper honeycomb body.