JPH03186312A - Filter for removing dust - Google Patents

Abstract

PURPOSE:To absorb deformation of connecting fittings by clamping and compressing the outer peripheries of connecting ends of a plurality of filter elements by means of the connecting fittings through inorganic fibers having elasticity. CONSTITUTION:Filters 4 for removing dust are disposed between an upper partition wall 2 and a supporting plate 3. Filter elements 8 are connected to the wall in such a manner that the outer periphery of each connecting end of the elements 8 is clamped and compressed by means of a two-piece split type connecting fitting 9 of heat resistant metal such as nickel chrome steel, etc., and inorganic fiber 10 having elasticity is interposed between the filter element 8 and the fitting 9. In this manner, even if differences in thermal expansion occur between the element 8 and fitting 9, the fiber 10 absorbs the differences by its elasticity, preventing thereby a gap from being produced. As a result, damages of filter elements can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a dust removal filter such as a ceramic filter used for removing solid matter from high temperature gas.

(Prior art) As methods for removing solids from gas, wet processing methods using scrubbers, etc., and dry processing methods using electrostatic precipitators, bag filters, etc. have been known for a long time. The transition to dry processing methods is progressing from the viewpoint of processing and sensible heat recovery. Particularly in the case of dust collection for high-temperature gases, electrostatic precipitators do not have sufficient collection efficiency or heat resistance, and bag filters only have a heat resistance of about 250°C, so S
Ceramic filters made of iC and the like are becoming popular.

However, there are limits to the dimensions that can be manufactured with ceramic filters, so in practice it is necessary to connect several filter elements. For this purpose, metal fittings are used for the connection parts up to 850℃ due to their strength and reliability, but because the coefficient of thermal expansion of the filter element made of SiC etc. and the metal fittings are different, When this happens, loosening or twisting occurs between the two. The former causes dust leakage and deformation between the filter elements, while the latter causes damage to the filter elements. These phenomena become even more noticeable, especially when heat cycles occur during operation.

Therefore, an idea has been taken to interpose a heat-resistant inorganic mortar with a coefficient of thermal expansion between the filter element and the connecting fitting. However, when the temperature is high, the adhesive peels off and a gap is created, and the position between the two is shifted due to the weight and fixing force acting on the filter element at this time, and when the temperature drops again, there are cases where prying occurs and damage occurs. there were.

(Issues to be Solved by the Invention!) The present invention solves the above-mentioned conventional problems, and despite having a structure in which multiple filter elements are connected by connecting fittings, gaps may occur even at high temperatures. There are no streaks, and there is no risk of damage to the filter element due to prying, and it has sufficient strength during installation and operation, and can absorb deformation of the connecting fittings that may occur when used for long periods at high temperatures. It was completed to provide a dust removal filter.

(Means for Solving the Problem) The above problem is solved by tightening and compressing the outer periphery of the connecting end of multiple filter elements with a connecting fitting via an elastic inorganic fiber. The present invention will be explained in detail with reference to the illustrated embodiments.

(Example) In Fig. 1, (1) indicates a can body constituting the dust collector body;
(2) is an upper partition wall provided inside the can body (1);
) is a support plate, and the dust removal filter (4) of the present invention is installed between the upper partition wall (2) and the support plate (3). Also, (5) is the dust-containing gas inlet formed on the side wall of the can body (1), (6) is the clean gas outlet formed at the upper end of the can body (1), and [7] is the backwash gas inlet. be.

The dust removal filter (4) of the present invention is made up of a plurality of filter elements (8) connected in series as shown in the figure, and in the embodiment, the filter element (8) is S
It is made by iC.

As shown in Figure 2, these filter elements (
The connection of 8) is made by tightening and compressing the outer periphery of each connection end with a two-piece connecting fitting (9) made of heat-resistant metal such as nickel chromium steel. However, in the present invention, the filter element (8) ) and the connecting fitting (9), an elastic inorganic fiber 00 is interposed between the connecting fitting (9) and the connecting fitting (9). As this inorganic fiber 00, A! O0. -3iO□quality, A
Ceramic fibers containing either lzOs or SiCij as the main component are suitable, and those with a layered or bulk shape are preferable; in the examples, the fiber diameter is 2.
．． A blanket of ceramic fibers of 8μ, specific gravity 2,6^1, o, -5to, is used.

Since such inorganic fiber 0IIl has appropriate elasticity, it can absorb the difference in thermal expansion between the connecting fitting (9) and the filter element (8) at high temperatures. However, between the inorganic fiber 00 and the connection fitting (9), or between the inorganic fiber 0m and the filter element (8),
) Since there is a possibility that a gap may be generated between the inorganic fiber 〇[D] and the inorganic fiber 〇[D] due to repeated heat cycles, it is preferable to bond the space between the inorganic fiber 〇 [D] and these using an inorganic mortar.

If the packing density of the inorganic fiber Qffl used is too low, the strength of the connection part will be insufficient and there is a risk of dust leakage.On the other hand, if the packing density is too high, the elasticity will gradually be lost during use, which makes it difficult to use the present invention. The purpose cannot be distantly related.

FIG. 3 is a graph showing the results of measuring the relationship between the filling density and the adhesive strength and the relationship between the filling density and the gap generated when ceramic fibers of AlzOs-3iO1 quality are used. As shown in this graph, as the packing density of inorganic fiber 〇 [D is increased, the adhesive strength in the fresh state increases, but the adhesive strength after heat cycling peaks at 400 to 600 kg/m3 and tends to decrease. Moreover, the gap after the heat cycle also increases rapidly when the weight exceeds 600 kg/bo because the elasticity is lost. In this way, All0s-3iO
xf no no 1! When using quality fiber OI, the packing density is preferably 400 to 600 kg/rd, and similar experiments have shown that when 1203 N inorganic fiber G11l is used, the packing density is 500 to 800 kg/rd.
kg/m, and when SiC inorganic fiber 00) is used, it is preferable to set the packing density to 420 to 720 kg/n (.The compression ratio of the inorganic fiber 00) to obtain such a packing density is: It is in the range of 20-40%.

In addition, the value of L/D, which is the ratio between the axial length L of the connection part and the diameter of the filter element (8), has a large effect on the bending strength (extraction strength) of the dust removal filter (4). . Figure 4 is a graph showing this relationship, and the diameter is 7.
1 in both cases of 0, 120 m, and 170 m.
When 4/D becomes less than 0.3, the bending strength decreases rapidly. Therefore, it is preferable that the value of L/D is 0.3 or more.

(Function) In the dust removal filter of the present invention configured as described above, the outer periphery of the connecting end of the plurality of filter elements (8), (8) is connected to the connecting fitting (9) via the elastic inorganic fiber 00. The filter element (8) and the connecting fitting (
9) Even if there is a difference in thermal expansion between
absorbs this with its elasticity and prevents the formation of gaps. For this reason, not only is the dust sealing property excellent, but there is no prying between the filter element (8) and the connecting fitting (9) even when heat cycles are applied, and damage to the filter element (8) due to stress concentration is prevented. In addition, sufficient bonding strength can be ensured, and in particular, if the packing density of the inorganic fibers IIl is within the range described above depending on the material, sufficient strength can be exhibited during installation and operation. In addition, by bonding between the inorganic fiber 〇 (11) and the connecting fittings etc. with an inorganic binding material,
Further, by setting the value of L/D to 0.3 or more, even more excellent effects can be exhibited.

In addition, if the inorganic fiber 〇〇 is impregnated with a silicate solution such as water glass and allowed to ooze out onto the surface during filling, the inorganic fiber 〇〇 [D] will harden on the surface and create a stronger bond. It will be done.

In order to confirm the above effects, the outer diameter was 170 mm and the inner diameter was 140 mm.
SiC filter element with a length of 700 m (
8) with the connecting fitting (9) as shown in Figure 2 and A1□0. −
A test was conducted in which 450" CO gas containing ore dust was filtered for 3°0 hours by connecting three fibers in a bottom row using 3i02 quality inorganic fibers Oa). The density was 450 kg/n (and the L/D value was 0.5. The filtration flow rate was 2 to 4 m/min, and the dust removal rate was 99.9% or more.
No dust leaks, damage, deformation, etc. were observed even after hours of use.

(Effects of the Invention) As explained above, the dust removal filter of the present invention does not generate gaps or leak dust even when used under high temperature conditions, and there is no fear of damage to the filter element due to prying. Further, since the dust removal filter of the present invention is made by connecting a plurality of filter elements, it can be made to have any size, and the connecting portion has sufficient strength. Therefore, the present invention greatly contributes to the development of industry as a dust removal filter that solves the problems of the conventional filters.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view showing an embodiment of the present invention, Fig. 2 is an enlarged cross-sectional view of the main part, Fig. 3 is a graph showing the relationship between packing density, adhesive strength, and the gap that occurs. The figure is a graph showing the relationship between the value of L/D and bending strength. (8): Filter element, (9): Connection fitting, 0
ω: Inorganic fiber

Claims (1)

[Claims] 1. A plurality of filter elements (8), (8),
The outer periphery of the connecting end is made of elastic inorganic fiber (
A dust removal filter characterized in that a filter element (8) is connected and integrated in the axial direction by tightening and compressing a connecting fitting (9) via a connecting fitting (9). 2. The inorganic fiber (10) is Al_2O_3-S
The main component is iO_2, Al_2O_3, or SiC, and the packing density is 400 to 6 in each case.
00kg/m^3, 500-800kg/m^3, 42
The dust removal filter according to claim 1, wherein the dust removal rate is 0 to 720 kg/m^3. 3. Filter element (8), inorganic fiber (
10) The dust removal filter according to claim 1, wherein the connection fittings (9) are bonded together with an inorganic binding material. 4. The dust removal filter according to claim 1, wherein the length/diameter value of the connecting part between the connecting fitting (9) and the filter element (8) is 0.3 or more.