JPH0113781Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a catalytic converter for exhaust gas purification.

In conventional converters for exhaust gas purification, a perforated plate was used to hold the catalyst layer. However, the perforated plate has a small porosity, so the openings are blocked by catalyst particles, which impedes the flow of exhaust gas from the engine, resulting in an increase in exhaust gas back pressure. Additionally, there was a problem in that the top surface of the catalyst in the filling chamber descended during use, causing exhaust gas to pass through and reduce purification performance.

The object of this invention is to provide a catalytic converter for exhaust gas purification that can eliminate the above-mentioned problems.

This devised catalytic converter for exhaust gas purification is
an upper casing having an exhaust gas inlet (outlet);
An annular ring consisting of outer and inner rings hung vertically on the upper casing, cylindrical outer and inner wedge wire screens vertically hung on these rings, and a closing plate fixed to the lower ends of these screens. a catalyst container having a filling chamber;
It consists of a lower casing surrounding the catalyst container and having an exhaust gas outlet (inlet) attached to the upper casing, and the outer and inner wedge wire screens are respectively arranged between the outer and inner rings and the closing plate. It is composed of a plurality of support rods, and a plurality of wedge wires having a triangular cross section are arranged in parallel at a desired pitch with their tops facing outside of the filling chamber. be.

An embodiment of this invention will be described below with reference to the drawings. As shown in FIG. 1, the exhaust gas purifying catalytic converter 1 is installed in the middle of the exhaust pipe 3 of the engine 2 to purify harmful exhaust gas, and the purified exhaust gas is sent to the atmosphere via a muffler 4. It is now being released into the world. The catalytic converter 1 includes an upper casing 11, a catalyst container 31 vertically disposed on the upper casing 11, and a lower casing 21 surrounding the catalyst container 31 and connected to the upper casing 11 by bolts.

The upper casing 11 is constructed by welding a short pipe 13, which is an exhaust gas inlet 12, to an annular closing plate 14 on which a catalyst container 31 is vertically installed, and a flange 15 for connecting to an exhaust pipe 3 to this short pipe 13. It is composed of Bolt holes 16 for attaching the lower casing 21 are drilled at equal pitches on the same circumference in the outer circumference of the annular closing plate 14. A socket 17 for filling the catalyst container 31 with pellet-type catalyst C is welded to the annular closing plate 14, and is closed by a plug 18 via a packing 19 when in use.

The catalyst container 31 includes a cylindrical outer wedge wire screen 32, an inner wedge wire screen 33 concentric with the cylindrical outer wedge wire screen 32, and
2 and 33, and a closing plate 34 welded to the lower ends of the catalyst C, forming a filling chamber 35 for the catalyst C. As shown in FIGS. 3 and 4, the outer wedge wire screen 32 is constructed by welding the upper end of a ring 41 with no air permeability and having a height h to the lower surface of the annular closing plate 14, and the outer circumference of the lower end surface of this ring 41. A plurality of support rods 43 are welded at equal pitches around the entire circumference, and a cross section 3 is formed on the inside of these support rods 43.
It is constructed by disposing rectangular wedge wires 44 with their tops facing outward at intervals of pitch P. This forms a screen having slits 45. In addition, the inner wedge wire screen 33
This has the same structure as the outer wedge wire screen 32, but in this case, a support rod 43 is welded to the inner periphery of the lower end surface of the ring 46, and the top of the wedge wire 44 is placed on the outside of the support rod 43, with the top facing inward. The difference is in how they are set up. Then, a closing plate 34 is welded to the lower ends of these screens 32, 33,
A filling chamber 35 for catalyst C is formed. A pellet type catalyst C is inserted into this filling chamber 35 from the socket 17.
to form a catalyst layer. When the catalytic converter 1 is warm, the top surface of the catalyst layer lowers due to the difference in thermal expansion coefficient between the filling chamber 35 and the catalyst C, creating a space above the filling chamber 35, but the height h of the rings 41, 46
By setting the height higher than the expected height of the space, it is possible to prevent exhaust gas from short-passing. Further, by changing the size and arrangement pitch P of the wedge wire 44, the width of the slit 45 can be changed and the aperture ratio can be set to an appropriate value. Further, by changing the size and number of support rods 43, the required strength for holding the catalyst layer can be obtained.

The lower casing 21 has a funnel part 25 welded to the lower end of a cylindrical part 24 having a size that surrounds the catalyst container 31, and an exhaust gas outlet 27 at the lower end of the funnel part 25.
The cylindrical part 24 is constructed by welding a short pipe 26 that becomes
A flange 22 with a screw hole 23 for connecting to the upper casing 11 is welded to the upper end, and a flange 28 for connecting to the exhaust pipe 3 is welded to the lower end of the short pipe 26. . The lower casing 21 has a packing 5 between the flange 22 and the annular closing plate 14 of the upper casing 11.
2, and is attached to the upper casing 11 by inserting the bolt 51 into the bolt hole 16 drilled in the annular closing plate 14 via the washer 53 and screwing it into the screw hole 23 of the flange 22. .

Therefore, the exhaust gas from the engine 2 enters the inlet 12.
It flows into the catalytic converter 1 through the catalytic converter 1, enters the catalyst layer from inside the inner screen 33, and exits outside the outer screen 32. At this time, the exhaust gas is purified by a catalyst C filled in the filling chamber 35, such as an oxidation catalyst, a reduction catalyst, or a three-way catalyst. Since the catalyst layer is held by wedge wire screens 32 and 33 having large porosity and having slits 45, the back pressure of exhaust gas can be kept low. The purified exhaust gas is guided to the cylindrical part 24 and the funnel part 25, is discharged from the outlet 27, and is discharged to the atmosphere via the muffler 4.

Furthermore, even if the pellet-type catalyst C is cracked or missing due to vibration or thermal deformation of the catalyst container 31, the slits 45 of the screen are widened toward the tip, so catalyst powder will not clog the screen. Since it spills easily, the back pressure of the exhaust gas does not increase due to clogging. Furthermore, even if the packed catalyst layer falls down due to its own weight, a ring 41 with no air permeability is installed at the upper end of the filling chamber 35.
46, the exhaust gas will not short-pass, and the purification performance of the exhaust gas will not be degraded.

Moreover, since the structure is simple, the catalytic converter 1 is assembled into one unit by connecting the lower casing 21 to the upper casing 11 with the catalyst container 31 vertically disposed thereon using bolts 51, so that it can be manufactured easily. Since it can be easily incorporated into the engine exhaust system using the upper and lower flanges 15 and 28, the exhaust gas emitted by the engine can be purified in a high temperature state, and a highly efficient purification action can be performed. .

Note that in the above embodiment, the exhaust gas flows through the upper inlet 1.
2, the exhaust gas is purified and discharged from the lower outlet 27. However, in the opposite direction, exhaust gas is introduced from the lower inlet 27, enters the catalyst layer from the outer periphery of the outer screen 32, and is then purified and discharged from the lower outlet 27. The same effect as described above can be obtained even if the liquid is discharged upward from the inside through the outlet 12.

This devised catalytic converter for exhaust gas purification is
As described above, the back pressure of exhaust gas can be suppressed lower than in the conventional case. Furthermore, it is possible to perform efficient purification with a simple structure.

[Brief explanation of drawings]

Figures 1 to 4 show one embodiment of this invention, with Figure 1 being an explanatory diagram of the catalytic converter installed in the engine exhaust system, Figure 2 being a longitudinal sectional view,
Figure 3 is an enlarged sectional view of the part in Figure 2, and Figure 4 is an enlarged cross-sectional view of the part in Figure 2.
FIG. 11...upper casing, 12...inlet (outlet),
14... Annular closure plate, 15... Flange, 17...
...Catalyst filling socket, 21...Lower casing,
27... Outlet (inlet), 28... Flange, 31...
... Catalyst container, 32 ... Outer wedge wire screen, 33 ... Inner wedge wire screen, 34 ... Closure plate, 35 ... Filling chamber, 41,4
6...Ring, 43...Support rod, 44...
...Wedge wire, 51...bolt.

Claims (1)

[Scope of utility model registration request] An upper casing having an exhaust gas inlet (outlet), outer and inner rings vertically disposed on the upper casing, cylindrical outer and inner wedge wire screens vertically disposed on these rings, and these screens. Consisting of a catalyst container having an annular filling chamber configured with a closing plate fixed to the lower end, and a lower casing surrounding the catalyst container and having an exhaust gas outlet (inlet) attached to the upper casing, The outer and inner wedge wire screens have a plurality of wedge wires each having a triangular cross section attached to a plurality of support rods disposed between the outer and inner rings and the closing plate, and the tops of the wedge wires are connected to the filling chamber. Catalytic converters for exhaust gas purification are arranged in parallel at a desired pitch toward the outside of the exhaust gas.