FI74522C - FOERFARANDE FOER INKAPSLING AV EN KATALYTCELL AVSEDD FOER RENING AV AVGAS. - Google Patents

Description

1 74522

The present invention relates to a method for supporting a catalyst cell for exhaust gas purification, in which the outer shell portions are arranged around at least one cell, after which the outer shell portions are fastened together to form a jacket around the cell.

The catalyst cells currently in use are mainly ceramic, which is why their propulsion requires special precision and care due to the fragility of the ceramic cells. U.S. Patent 4,328,188 discloses a support method in which the sheath forming the outer shell of a catalyst cell consists of two shell halves welded to one of their edges. The longitudinal movement of the catalyst cell is prevented by forming a protrusion in the shell halves to which the cell fits and by permanently fixing the cell using a separate fastening member which is welded to the shell. The separate fastening member may be a simple collar. In addition, some flexible material, such as a steel wire braided mat or heat-resistant felt, must be placed between the sheath and the honeycomb to prevent the honeycomb from being knocked over. This also prevents possible disadvantages due to thermal expansion.

U.S. Patent 4,400,860 discloses a method of supporting a metal honeycomb in which the honeycomb is placed between two shell halves which are pressed together and welded to the seams. The honeycomb and the jacket are attached to each other by spot welding or soldering.

Prior art methods require the use of expensive press tools to make shell halves, and if the catalyst is to be resized, new tools are always required, which is costly. In order to keep costs reasonable, known methods require the production of long series 2 74522 to be profitable. However, since there are many car brands and models, and the same catalyst cannot be installed on different brands, the conversion of the outer shell should be easy without high tool costs.

It is an object of the present invention to provide a catalyst cell support method which does not have the disadvantages of the previously known methods. This is achieved according to the invention by fitting a metal honeycomb inside a tube, the first end of which is optionally pre-formed into a cone, and then forming one or both ends of the tube into cones, the honeycomb placed inside the tube being attached at its ends to the outer jacket. covering only the conical ends of the tube.

In the support method according to the invention, two shell halves have been replaced by a tube and two end cones 1a. The catalyst can be adapted to different car brands and models simply by changing the length or diameter of the tube and changing the end cones, which is easy and cheap to implement.

For example, a standard steel tube can be used as the tube and the end cones can be made with relatively inexpensive press tools. The shape of the tube used as the catalyst jacket can be varied from round to oval, so the best possible solution can be found for each car brand. However, a round pipe is often the best and easiest structural solution. The catalyst support method according to the invention is thus easily modified and is also suitable for small series.

The metal honeycombs used in the method can withstand any mechanical stresses that may occur during both the propulsion and operation phases without breaking. Thus, there is no need for any type of flexible material between the jacket and the honeycomb, like a ceramic honeycomb, which reduces the size of the catalyst and reduces the manufacturing and material costs.

3,74522

The longitudinal movement of the catalyst cell inside the outer shell can be prevented by the method according to the invention in a simple manner. A honeycomb is placed in a tube, the first end of which can optionally be pre-formed into a cone, after which one or both ends of the tube are pressed into cones, whereby the honeycomb inserted into the tube is immobilized inside the jacket. Appropriate end cones are then welded to the ends of the pipe and the supported catalyst cell is complete.

According to an embodiment of the invention, one or two inwardly directed grooves are formed in the metal tube, and two metal cells are placed in the tube, one end of which is held in place by the groove (s) formed in the tube.

Of course, more than two honeycombs can also be placed in the pipe, in which case these honeycombs are fastened at both ends by means of grooves formed in the pipe.

The invention will now be illustrated with reference to the accompanying figures, in which Figure 1 shows a support method according to the invention using one cell, and Figure 2 shows an embodiment according to the invention with two cells.

Figure 1 shows a metal tube (2) with one end formed in a cone (3). A catalyst cell (1) is placed inside the pipe. The straight end of the tube is then formed into a cone and the end cones (4) are attached to the ends of the tube.

Figure 2 shows a metal tube (2) inside which two honeycombs (1) are placed. The honeycombs are fixed in place at the open ends of the tube by forming the ends of the tube into cones (3) and the inner ends of the honeycombs are held in place by grooves (5) formed inwardly in the tube. In the last step of the method, end cones (4) are attached to the ends of the pipe.

Claims (4)

4,74522 Patent Requirements A method of supporting a catalyst cell for exhaust gas purification, wherein the outer shell portions are arranged around at least one cell, after which the outer shell portions are attached to form a sheath around the cell, characterized in that a metal cell (1) is placed inside a tube (2). the end is optionally pre-formed into a cone (3), and then one or both ends of the tube are formed into cones (3), the honeycomb fitted inside the tube being attached at its ends to the hard shell, and then suitable end cones (4) are attached to the tube ends. formed ends. Method according to Claim 1, characterized in that one or two inwardly directed grooves (5) are formed in the tube (2) and two honeycombs (1) are arranged in the tube, the other end of which is held in place by the groove (s) (5) formed in the tube. Method according to Claim 1 or 2, characterized in that the tube (2) is oval. Method according to one of Claims 1 to 3, characterized in that the pipe is made of metal and the metal end cones are fastened by welding.