JPS6189916A - Seal-mat with concaves for exhaust gas purifying device - Google Patents

Abstract

PURPOSE:To reduce excessive occurrence of surface pressure to honeycomb catalyzer by providing concaves on one side or both sides of a seal-mat consisting of heat-resistant fiber. CONSTITUTION:A seal-mat 1 consists of heat-resistant fiber such as asbestos, rock wool, ceramic fiber, carbon fiber, etc. Concaves 1a of optional profile and amount are provided on one side or both sides of the seal-mat. Providing means of concaves are also optional. Owing to the concave provision, when excessive compression is applied, one part of convex portions (b) of the surface of seal-mat 1 moves to the concave portions 1a and the compression is reduced, and as a result, breaking possibility of honeycomb catalizer is largely lowered.

Description

[Detailed Description of the Invention] [Field of Application] The present invention relates to a honeycomb contact (sealed pine with concave portions having improved winding characteristics and excellent airtightness) in an exhaust gas purification device. It is something.

[Conventional technology]

Conventionally, a seal mat made of heat-resistant fiber is used by being wrapped around the side of a honeycomb catalyst used to purify automobile exhaust gas, etc., which consists of a catalyst and a ceramic cylinder integrally molded into a honeycomb shape. C. For example, there is known a product manufactured by 3M Company in the United States (trade name: Intalum Mat) which is made by bonding ceramic fibers and vermiculite with a binder. this is,
The previous method of wrapping a corrugated wire mesh around the side of the honeycomb catalyst resulted in a 5-7% exhaust gas leak rate, so this method was proposed as a means to improve sealing performance. be.

[Problems to be solved]

However, when the above-mentioned mat is wound around more than half of the length of the side peripheral portion of the honeycomb catalyst and housed in a case (FIG. 2), there is a problem that the honeycomb catalyst is damaged during the assembly. This damage problem is caused by extremely large variations in the finished outer diameter of the honeycomb catalyst currently in use. This variation causes variation in the size of the gap between the honeycomb catalyst and the case,
Therefore, when the honeycomb catalyst is housed in a case, this is reflected in the variation in the compressive force of the seal mat, and when the seal mat is excessively compressed, the compression stress causes damage to the honeycomb catalyst.

Solution to Problem c] The present invention proposes a new seal mat that can overcome the above problems, and provides an exhaust gas purification device in which an integrally formed honeycomb catalyst is housed in a case. ml is wrapped around the side shoulder of the honeycomb catalyst. The present invention provides a sealing mat made of heat-resistant fibers and having concave portions on one or both sides of the honeycomb catalyst to alleviate generation of excessive surface pressure against the honeycomb catalyst.

[Effects of Embodiment 9] FIG. 1 is a perspective view of an embodiment of the present invention, in which concave portions 1a are provided on both sides of a seal mat 1 that are continuous in the longitudinal direction of the mat.

FIG. 2 is a sectional view of the honeycomb catalyst 2 housed in a stainless steel case 3 using the seal mattora of FIG. In order to improve the sealability of the seal mat IK, the seal mat 1 is interposed between the honeycomb catalyst 2 and the case 3 in a suitably compressed state through a storage process to be described later. Due to this, when excessive compressive force is applied, a part of the convex part on the surface of the seal mat 1 moves to the concave part 1alC, and the compressive force is alleviated, and as a result, the degree of damage to the honeycomb catalyst is significantly reduced. do. Note that the recess 1aK
Even with the above-mentioned compressive force relaxation effect, the convex portions on both sides of the seal mat 1 still have two honeycomb contacts.
Since the seal mat 1 is in close contact with the surface of the case 3 or the inner surface of the case 3, the seal mat 1 maintains good sealing performance.

The recesses provided on the surface of the seal mat in the present invention have the above-described function. As long as this function is achieved, the shape, amount, and arrangement of the recesses may be arbitrary. For example, examples include the one shown in FIG. 1, the one with a corrugated surface, the one with base grooves, the one with many discontinuous depressions, etc. The size of the recess is determined by the gap between the honeycomb catalyst 2 and the case 3, the thickness of the seal mat, compression resistance, etc. For example, the above gap is 1.5 to 4u, the thickness of the seal mat before compression is about 5ff, and its 65% compression resistance is 7.
In the case of 0 to 150 kgf/d, depth 2,
It is appropriate to provide continuous grooves with a width of 21 nI on at least one side of the seal mat at intervals of 2 to 10 ff.

The seal mat 1 of the present invention is made of, for example, asbestos, rock wool, ceramic fiber, carbon l!, etc. in order to withstand the high temperature of exhaust gas. It is made of heat-resistant fibers such as alIa/galanu fibers, sufugu wool, and metal fibers. A tape made of fine fibers is preferably used from the viewpoint of airtightness.

The seal mat of the present invention can be produced by impregnating a heat-resistant nonwoven fabric with a heat-resistant adhesive such as an alkali metal silicate-based inorganic adhesive, a phosphate-based inorganic adhesive, or an alkyl silicate-based inorganic adhesive. This can also be done by layering them.

Contains substances that have a lower melting point than the heat-resistant fibers used, such as aluminum powder, calcium powder, lead powder, barium powder, sodium chloride, and calcium chloride, and that melt at a temperature higher than the temperature of the exhaust gas flowing into the purification device. A non-woven fabric made of heat-resistant fibers was impregnated with a liquid adhesive, and the resulting mat was heated to melt the substance, and then cooled and solidified to bond the heat-resistant fibers with the substance. This can also be done by forming a mat. In the latter method, the liquid adhesive used usually ashes and disappears during the heat treatment process. Incidentally, heat-expandable additives such as vermiculite may be added to seal pine) K.

〔Effect of the invention〕

If the seal mat of the present invention is used, even if existing honeycomb catalysts with large variations in finished outer diameter are used, the damage rate of honeycomb catalysts during assembly will be significantly reduced, which will improve the yield of juice in the production of exhaust gas purification devices. Moreover, the obtained purification device has excellent sealing ability.

[Comparative example, application example]

Interlam mat (product name, US 3M ), a ceramic honeycomb catalyst with a diameter of 10a11 and a length of 201J! Wrap it once around the 41st circumference and store it in one half of a stainless steel case.
Next, the other cake was placed on top of it, and pressure was applied until the welding parts of both halves of the case came into contact. The gap between the honeycomb catalyst and the inner surface of the case upon completion of compression is 2. O
It was B.

When the above assembly work was performed 5 times, 3 of them were
The internal honeycomb catalyst was damaged due to the above pressure.

Next, a mat of the same size as the above-mentioned interlam mat taken from the same production loft as the above-mentioned intalum mat was placed on both sides with a depth of 2ff and a width of 2M.
When the same assembly operation as described above was repeated five times using a honeycomb catalyst having vertical grooves arranged at intervals of 5f1, no damage to the honeycomb catalyst was found.

[Brief explanation of drawings]

1. FIG. 1 is a perspective view of a seal mat according to an embodiment, and FIG. 2 is a sectional view showing a structural example of an exhaust gas purification device to which the seal mat is applied.

Claims (1)

[Claims] 1. In an exhaust gas purification device in which an integrally formed honeycomb catalyst is housed in a case, it is made of heat-resistant fibers that are wrapped around the side circumference of the honeycomb catalyst, and alleviates excessive surface pressure against the honeycomb catalyst. A sealing mat with recesses on one or both sides.