DE102005029747A1 - Support mat for elements of exhaust system consists of mineral fibers and is constructed free of swelling means and/or fibers are exclusively mechanically interlinked and have constant diameter over longitudinal extent - Google Patents

Abstract

The support mat (1) consists of mineral fibers and is constructed free of swelling means and/or the fibers (2) are exclusively mechanically interlinked. The fibers have a constant diameter over their longitudinal extent and/or are endless drawn from a molten mass and/or the fibers have a diameter of over 3 microns and/or a length of at least 20 mm. The support mat consists exclusively of the aforesaid fibers. An independent claim is included for an arrangement of a support mat of fibers for the support of an element such as a particle filter, catalyser, honeycomb core or silencer in a housing of an exhaust system, whereby the support mat is installed in a gap between the element and housing.

Description

The The present invention relates to a storage mat according to the preamble of claim 1, a method for producing such Storage mat as well as a use of a storage mat for storage an element, such as a particulate filter, catalyst, monolith or silencer, in a housing an exhaust system.

A Storage mat according to the present invention is used for storage an element of an exhaust system, in particular a particle filter, a catalyst, a monolith of a muffler or like. The storage mat is usually between a metal housing and the existing example of ceramic element. The storage mat is thermal, mechanical and chemical in use Loads exposed and must this Withstand loads. Furthermore, the storage mat must have sufficient elasticity even with continuous use keep to the item in the exhaust system secure to fix.

Usually currently storage mats of mineral fibers, which are held together by a binder used, such as from DE 196 38 542 C2 known. Practice has shown that the binders are often not sufficiently resistant to the high temperature loads over time. This has the consequence that the mechanical properties of binder-containing storage mats deteriorate over time and often fibers of the storage mat can be blown out by exhaust gases in an undesirable manner.

In The practice is very common Storage mats, in particular ceramic mats, used with fibers, which are produced by centrifuging or in the sol-gel process or in the silane process and partly a conical shape with often relatively thick Melt bead at the rounded end. In use, especially due to the mechanical loads break individual fibers. In the known Fibers there is a risk that respirable fragments with a diameter of less than 3 microns discharged or released in the production process become. This is hazardous to health.

Of the present invention is based on the object, a storage mat, a method for producing such a storage mat and a Use a storage mat specify, with a simple and cost-effective Construction with good durability, in particular being an undesirable Blowing out fibers or respirable fiber components avoided or at least minimized.

The The above object is achieved by a storage mat according to claim 1, a method according to claim 12 or a use according to claim 15 solved. Advantageous developments are the subject of the dependent claims.

The proposal provides that that the storage mat blähmittelfrei is formed and / or the fibers exclusively mechanically with each other are chained that the Fibers one over each Your longitudinal extension have constant diameter and / or endless liquid melt are drawn and / or that the Fibers each have a diameter of about 3 microns and / or a length of at least 20 mm.

Preferably the storage mat consists exclusively of the fibers. Especially is therefore neither a blowing agent still contain a binder. This allows a simple and affordable Production. Next can be prevented so that, for example a binder due to the thermal stresses with time "burns" or its fixing effect in terms of the fibers decreases.

The Using fibers with constant diameter leads too much defined mechanical properties. Furthermore, it can be prevented be that at the inevitable breakage of individual fibers respirable fragments may arise.

Endless from liquid Melt drawn fibers are very inexpensive to produce and have an at least largely constant diameter on This is in turn a defined mechanical behavior beneficial.

Prefers the fibers have a diameter of about 3 microns, in particular of at least 4 μm, especially preferably at least 6 μm, on to a pulmonary function the fibers, if they are blown out to be able to exclude. Problematic is namely, that respirable fibers or pieces of fiber be considered carcinogenic.

The preferred length of the fibers of at least 20 mm, in particular at least 40 mm or even 50 mm, on the one hand leads to a surprisingly good cohesion of the storage mat - even without binders or the like - and on the other hand to good mechanical properties of the storage mat with respect to the fixation of the supplied arranged element in the exhaust system. In addition, the large length makes it difficult to blow out individual fibers.

A simple preparation of the storage mat is obtained by two layers of fibers with fibers directed substantially opposite obliquely to the main plane or production layer stacked and compressed or pressed together, in particular so that the density of the storage mat in the uninstalled state 100 to 250 kg / m ³ . This allows a simple and inexpensive production of the storage mat.

Preferably the purely mechanical linking of the fibers takes place by needling, in particular from the opposite flat sides of the storage mat.

Especially Glass fibers are preferred except R-glass fibers, in particular modified glass fibers, with sufficient Temperature resistance used. This allows a cost-effective Production and achievement of good mechanical properties of the Positioning mat.

alternative can but also other, in particular also endless from the liquid melt drawn fibers such as silicate fibers or the like used become.

In particular, the storage mat has a density of 100 to 250 kg / m ³ in the uninstalled state. In the installed state, the density then increases in particular to 150 to 600 kg / m ³ in order to achieve the desired secure fixation of the element in the exhaust system and in particular to achieve a contact pressure of 70 kPa or more and correspondingly high holding forces.

Preferably the use of the storage mat is such that the storage mat in a gap between the element to be fixed and a housing of Exhaust system is installed so that the storage mat bridges the gap. The Length of Fibers when used as intended is while at least 3 times, preferably at least 5 times and in particular at least 7 times the gap. The thickness of the storage mat before installation is generally greater than the gap and is preferably at least 1.5 times the gap. This allows safe storage of the element to be held in the Exhaust system and leads to that individual Fibers of the storage mat even without a binder or at best only in negligible Dimensions blown out can be.

Further Aspects, advantages, features and characteristics of the present invention arise from the claims and the following description of a preferred embodiment. It shows:

1 a schematic representation of the proposed production of a proposed storage mat; and

2 a schematic representation of the storage mat in the installed state.

1 illustrates in a schematic diagram only a preferred production of a proposed storage mat 1 made of mineral fibers 2 , By a corresponding air flow and by means of two cylinders or the like from the fibers 2 formed two layers, which are brought together or stacked on top of each other. The individual fibers 2 are at least substantially opposite to each other before the final installation or at least in the initial phase of manufacture and obliquely to the conveying or production direction according to arrow P or to the main plane of the mounting mat 1 directed. Preferably, the storage mat 1 constructed only from the two layers, in particular as a single-layered, single-layered and / or substantially homogeneous.

The storage mat 1 with the initially relatively loose layers of fibers 2 is preferably compressed by means of further rollers or the like pre-compressed in order to achieve a preferred density of 100 to 250 kg / m ³ in the non-installed state - especially after needling.

The storage mat 1 preferably consists exclusively of the fibers 2 , In particular, therefore, no binder, blowing agent or the like is provided. The fibers 2 are accordingly linked only mechanically.

In order to ensure sufficient mechanical interlinking, the fibers become 2 preferably needled together, in particular from opposite sides of the storage mat 1 , This needling is in 1 not shown.

As fibers 2 For example, glass fibers other than R glass fibers are preferably used. However, other mineral fibers, in particular silicate fibers, can also be used.

The fibers 2 are resistant to high temperatures, preferably up to 600 ° C., in particular up to 800 ° C., most preferably up to 1000 ° C or more.

The Fibers are preferably drawn endlessly from a melt and have a constant diameter. The diameter is at least 3 μm, preferably at least 4 μm and in particular at least 6 microns or more. According to one most preferred embodiment is the diameter essentially 9 μm with a tolerance of at most 3 μm.

The length of the fibers 2 is at least 20 mm, preferably at least 30 mm or 40 mm and in particular about 50 mm or more.

The fibers 2 each preferably have a bending force of less than 0.01 mN. This represents a measure of the bending stiffness. The intended limit for the bending force leads to an at least specific elasticity of the fibers 2 ,

The determination of the bending force is preferably carried out on a bundle of 50 fibers 2 , which are clamped on one side under a fineness-related prestressing force of 5 mN / tex. The bending force P is the force needed to bend the fibers 2 by 30 ° with a free clamping length of 2 mm is required.

The fibers 2 preferably each have a fracture torsion number of at least 0.05. The fracture torsion number is a parameter for evaluating the brittleness. The fibers 2 are preferably clamped in groups of, for example, 50 fibers or individually in a fixed and in a rotatably mounted about its longitudinal axis clamp a torsion device and rotated to break, the distance of the terminals is kept constant. From the free clamping length 1 , the average number N of rotations of the clamp to break, and the average fineness T and density ρ of the fibers, the ^{fracture torsion number B is} calculated according to 2 · π ^½ · 1 ^-1 · T ^½ · ρ ^-½ · N.

The fibers 2 preferably each have a loop strength in the raw state of at least 1 cN / tex and / or in the installed state of at least 0.7 cN / tex. To determine the loop strength, two fibers are intertwined in an U-shaped manner. The fibers 2 are clamped in separate clamps. The distance between the clamps is increased until one of the clamped fibers breaks in the loop of the loop. The loop strength is then taken into account the fineness of the fibers 2 as the quotient of the mean loop breaking force F in mN and the mean normal climate fineness T in tex, ie according to F / 2T.

2 shows a schematic, partially sectional representation of a proposed use of the storage mat 1 for storage of an element 3 , such as a particulate filter, catalyst or muffler, an exhaust system 4 , in particular in a housing 5 the exhaust system 4 , The storage mat 1 is in particular radially between the element to be held 3 and the housing 5 the exhaust system 4 built-in. Preferably in a gap 6 between the element 3 and the housing 5 , This is the storage mat 1 further compressed, in particular so that a contact pressure of the mounting mat 1 in the installed state of at least 70 kPa, preferably 80 kPa or more, is achieved.

The gap S of the gap 6 is usually 3.5 to 7 mm. According to a preferred use, the length of the fiber is 2 at least 3 times, preferably at least 5 times, in particular at least 7 times, the gap dimension S. This tuning leads to very good mechanical properties of the mounting mat in the installed state 1 and prevents or reduces the blowing out of individual fibers 2 in the installed state.

The thickness of the storage mat 1 in the non-installed state is preferably at least 1.5 times, in particular 2 times or more of the gap S. Thus, the required compression of the storage mat 1 in the installed state, to a secure holding the element 3 in the housing 5 to be ensured.

The thickness of the storage mat 1 is preferably 3 to 25 mm, in particular about 6 to 12 mm. The basis weight of the storage mat 1 is preferably 500 to 4000 g / m ² .

Experiments have shown that the proposed storage mat 1 and the proposed use to a very good assurance of the element 3 in the case 5 lead, wherein in the proposed solution, a density of the storage mat 1 in the installed state of 150 to 600 kg / m ³ , in particular substantially from 250 to 450 kg / m ² , in contrast to about 1000 kg / m ² in the prior art is sufficient. This illustrates the superior mechanical properties of the proposed solution.

In addition, the proposed storage mat is 1 or their use harmless to health, insofar as the emergence and expulsion of respirable fibers or pieces of fiber is avoided.

Claims (20)

Storage mat ( 1 ) of mineral fibers ( 2 ) except R-glass fibers for an element ( 3 ), such as a particulate filter, catalytic converter, monolith or silencer, in an exhaust system ( 4 ), thereby ge indicates that the storage mat ( 1 ) is formed without blowing agent and / or the fibers ( 2 ) are linked together mechanically only, that the fibers ( 2 ) each have a diameter which is constant over their longitudinal extension and / or are drawn endlessly from liquid melt, and / or that the fibers ( 2 ) each have a diameter of about 3 microns and / or a length of at least 20 mm. Storage mat according to claim 1, characterized in that the storage mat ( 1 ) exclusively from the fibers ( 2 ) consists. Storage mat according to claim 1 or 2, characterized in that the storage mat ( 1 ) is monolayered and / or substantially homogeneous. Storage mat according to one of the preceding claims, characterized in that the storage mat ( 1 ) from an upper and lower layer of fibers ( 2 ), wherein the fibers ( 2 ) of the two layers at least before the final mechanical chaining of the fibers ( 2 ) or deformation of the storage mat ( 1 ) substantially opposite obliquely or perpendicular to the main plane of the mounting mat ( 1 ) are aligned. Storage mat according to one of the preceding claims, characterized in that the fibers ( 2 ) are preferably exclusively needled for mechanical interlinking, in particular simultaneously or from opposite sides of the support mat ( 1 ). Storage mat according to one of the preceding claims, characterized in that the fibers ( 2 ) are resistant to high temperatures. Storage mat according to one of the preceding claims, characterized in that the fibers ( 2 ) are formed as silicate fibers or glass fibers other than R glass fibers or a mixture thereof. Storage mat according to one of the preceding claims, characterized in that the fibers ( 2 ) have an average diameter of at least 4 μm, preferably at least 6 μm. Storage mat according to one of the preceding claims, characterized in that the fibers ( 2 ) have an average length of at least 40 mm, preferably substantially 50 mm or more. Storage mat according to one of the preceding claims, characterized in that the fibers ( 2 ) each have a bending force of less than 0.01 mN and / or in each case a fracture torsion number of at least 0.05. Storage mat according to one of the preceding claims, characterized in that the fibers ( 2 ) have in each case a loop strength in the raw state of at least 1 cN / tex and / or in the installed state of at least 0.7 cN / tex. Method for producing a storage mat ( 1 ) according to one of the preceding claims, wherein two layers of fibers ( 2 ) with fibers directed essentially opposite to the main plane or production direction ( 2 ) are stacked and compressed or pressed together. Method according to claim 12, characterized in that the fibers ( 2 ) in particular alternately or simultaneously from opposite sides of the support mat ( 1 ) are needled. Method according to claim 12 or 13, characterized in that the density of the support mat ( 1 ) is 100 to 250 kg / m ³ when not installed. Use of a storage mat ( 1 ) of fibers ( 2 ) for storing an element ( 3 ), such as a particulate filter, catalyst, monolith or muffler, in a housing ( 5 ) an exhaust system ( 4 ), wherein the storage mat ( 1 ) into a gap ( 6 ) between the element ( 3 ) and the housing ( 5 ) and bridges it, whereby the length of the fibers ( 2 ) at least 3 times the gap dimension (S) and the thickness of the storage mat ( 1 ) before installation is at least 1.5 times the gap (S). Use according to claim 15, characterized in that the length of the fibers ( 2 ) is at least 5 times, in particular at least 7 times, the gap dimension (S). Use according to claim 15 or 16, characterized that this Gap (S) 3.5 to 7 mm. Use according to one of claims 15 or 17, characterized in that the density of the support mat ( 1 ) in the installed state is 150 to 600 kg / m ³ . Use according to one of claims 15 or 18, characterized in that the contact pressure of the support mat ( 1 ) is at least 70 kPa when installed. Use according to one of claims 15 or 19, characterized in that the support mat ( 1 ) is formed according to one of claims 1 to 11.