JPH01179772A - Perforated formed body - Google Patents

Abstract

PURPOSE:To prevent the release of a surface layer due to the thermal shock or local external force and to obtain the title durable formed body by unidirectionally arranging plural extruded looped coils of an inorg. material on a plane, and joining adjacent coils to a specified length. CONSTITUTION:A porous inorg. material (e.g., zeolite) is added with a binder (e.g., CMC), and kneaded. The mixture is extruded in the form of a loop while moving an extruding die in the arranging direction 4. The obtained strand 3 is looped, and sent onto a planar receiving surface. The centers of the plural coils 1 are shifted with the specified arranging pitch in the arranging direction 4 to arrange the coils. Plural coils 1 are partly overlapped, and a coil array 2 arranged in the arranging direction 4 is formed. Plural coil arrays 2 are arranged in parallel on one plane to form one layer, and plural layers are laminated and solidified. The coils of the adjacent coil arrays are overlapped to a length greater than the diameter of the strand and of <=1/2 times the coil diameter, and joined.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a porous molded body used as a permeable solid for molten metal filter media and high-temperature radiant plates.

[Prior Art] Conventional porous molded bodies include ceramic foam types and honeycomb types, but both of these are susceptible to thermal shock and crack when exposed to thermal shock, such as when suddenly exposed to direct flame. It has the disadvantage of being stored away.

On the other hand, strands of wire with a wire diameter of 0.5 to 6.0+ nm are formed into a waveform or loop shape in the same plane approximately perpendicular to the thickness direction of the formed body, and some of the wires are stacked on top of each other in one direction. A linear porous molded body arranged in a staggered manner has attracted attention as a molded body that has little structural restraint and is relatively resistant to thermal shock.

FIG. 7 is a schematic diagram showing a conventional linear porous molded body. A single strand of wire extruded from the nozzle of the die is wound into a loop to form a wire ring 1, and by shifting this wire ring 1 in one direction and arranging it so that a part of it overlaps, a wire ring train is created. 2 are configured. Then, a plurality of these train wheels 2 are arranged in parallel with each other on the same plane, and the next upper layer train train is placed on top of this train train 2 so as to straddle an adjacent pair of train wheels 2. Layer 2. By stacking a plurality of layers of wire wheel trains in this manner, a linear porous molded body is obtained. In addition, as mentioned above, this wire train 2 is overlapped in the thickness direction of the molded body. Therefore, in the lowest layer of the molded body, each train wheel train is placed on the same plane, or from the second layer onwards, it is superimposed on the train train in the lower layer. In this way, the train wheels superimposed on the train train can also be considered to be substantially placed on the same plane.

[Problem to be solved by the invention] However, in the conventional linear porous molded body, within the plane formed by the wire ring 1 obtained by molding the strands,
The wire wheels 1 do not overlap each other between the plurality of wire wheel rows 2 arranged in parallel.

Therefore, each train wheel train 2 is only connected to the train wheel train 2 stacked on the upper or lower layer. In addition, since the wire train 2 is laminated without intertwining with the extruded wires forming the wire ring (or waveform) in the upper or lower layer, the wire train 2 is exposed to high temperatures, especially in the thickness direction of the molded product, when used as a molded product. If a strong thermal shock that causes a distribution is applied, or if a local external force is applied to one of the wire wheels on the surface of the molded object, one row of wire wheels on the surface of the molded object will peel off. There is a problem with this.

The present invention has been made in view of such problems, and includes:
It is an object of the present invention to provide a long-life porous molded body that prevents peeling of the surface layer due to thermal shock or local external force while taking advantage of the advantages of a linear porous molded body.

[Means for Solving the Problems] The porous molded article according to the present invention has a plurality of wire rings formed by extruding an inorganic substance into a loop shape and arranged in one direction to form a plurality of wire wire rows. The multiple rows of wire wheels are arranged on the same plane, and the wires of adjacent wire wheels are separated from each other so that the wire diameter of the wire is greater than or equal to 1/2 of the diameter of the wire. It is characterized by being joined together by overlapping each other in length.

[Function] In the present invention, for example, a plurality of wire rings are formed by extruding an inorganic substance in a loop shape, and each wire ring is arranged with its axial center shifted in one direction.

A plurality of the train wheels obtained in this way are arranged in parallel on the same plane, and the wire wheels in the adjacent train wheels are partially overlapped and joined together.

Length L of the overlapped portion of this adjacent train wheel train
If the wire diameter of the wire is d and the diameter of the wire is D, then the following inequality is satisfied.

d≦L≦D/2 As a result, the train wheel trains located on the same plane are mutually joined and reinforced, preventing separation of the train wheels and preventing fluid flow from being inhibited. .

Note that when a porous molded body is constructed by laminating multiple wire ring forming layers each consisting of a plurality of wire ring rows arranged on the same plane, the lower layer forming layer is strictly speaking concave = 5 - convex. In fact, in the upper molding layer placed on this lower molding layer, each train wheel train is on the same plane.
Although there may be slight deviations from the above, in this specification,
Such a train wheel train is also considered to be on the same plane.

[Example] Hereinafter, an example of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a plan view showing a porous molded body according to an embodiment of the present invention. While moving an extrusion die (not shown) in the arrangement direction 4, the inorganic material is extruded from the extrusion die in a loop shape, and while the obtained wire 3 is wound in a loop shape, the flat receiver is ). Then, the plurality of wire rings 1 are arranged with their centers shifted by a predetermined arrangement pitch in the arrangement direction 4. This results in
A wire train row 2 is formed in which a plurality of wire wheels 1 are arranged in an arrangement direction 4 by partially overlapping each other.

A plurality of such wire ring rows 2 are arranged in parallel on one plane to constitute one layer of wire forming layer made of extruded strands of inorganic material, and such wire forming layers are made up of six or more layers. They are laminated to form a linear porous molded body. 1 space for each wire ring,
The inorganic material strands 3 are stacked in a softened state between the wire wheel trains 2 and between the wire forming layers, and then the inorganic material is solidified to be fixed.

As the inorganic substance, either a porous inorganic substance or a non-porous inorganic substance may be used.

First, examples of porous inorganic substances include synthetic or natural zeolite, γ-alumina, silica gel, silica/alumina, boehmite, activated titania, activated carbon, molecular sieve carbon, and the like. Examples of non-porous inorganic substances include metal oxide-containing minerals such as Murai I, corantum, and cordierite. These inorganic substances are generally available in the form of powder or granules.

In order to make these inorganic substances into a viscoelastic material, for example, a binder may be added to the inorganic substance, the mixture may be kneaded, and the viscosity may be adjusted to form a slurry.

As the binder, it is preferable to use one that exhibits a caking function for powder and granules, and various materials can be used. Typical binders include MC and CMC1.
Starch, CM3 (carboxymethyl starch), HEC (
Hydroxyethyl cellulose>, HPC (hydroxypropyl cellulose), sodium lignin sulfonate,
Organic binders such as calcium lignin sulfonate, polyvinyl alcohol, acrylic esters, methacrylic esters, phenolic resins, and melamine resins, and inorganic binders such as water glass, colloidal silica, colloidal alumina, colloidal titanium, bentonite, nitric acid, and aluminum. be. In addition, these binders are
More than one species may be used in combination.

Further, the blending ratio of the binder is preferably 35% or less (based on the total crosstalk) on a dry weight basis. If the blending ratio exceeds 35%, the strength of the final product tends to decrease.

Each train wheel train 2 arranged in one plane is partially overlapped with each other. Figure 2(a).

(b) is a schematic plan view for explaining this overlapping distance (hereinafter referred to as weight distance). As shown in the figure, the wire diameter of the wire ring 1 is d, the diameter of the wire ring 1 is D, and the weight allowance is L. However, the wire diameter is defined by the distance between the centers of the wires 3 constituting the wire 1, and the weight allowance is understood as the distance between the outer edges of the wire 1. In addition, Fig. 2 (a>,
(b) shows only one train wheel 1 for each train wheel train 2.

As shown in FIG. 2 (a>), in the adjacent wire wheel trains 2, the overlapping portion of the wire wheels 1 overlapping each other is greater than or equal to the wire diameter d.If the overlapping portion is less than the wire diameter 6, the wire Since the bonding area between the wheels 1 is small and the bonding force is low, separation of the wire wheel train 2 is likely to occur.

Since the wire wheels 1 have a circular cross section, when the wire wheels 1 are stacked on top of each other, they are substantially joined at a point. and,
The size of the joint is determined by the weight of the wire ring 1 and the softness of the wire 3. In this case, when the coils 1 are overlapped with their centers coincident, the joint surfaces become linear and the joint area becomes the widest. When the centers of the wires shift, the bonding area decreases. In particular, when the weight allowance becomes smaller than the wire diameter d, the bonding area becomes extremely small and the fixing strength becomes extremely low.

In Figure 3, the horizontal axis represents the weight allowance of the wire ring 1, and the vertical axis represents the probability that the wire train will not peel off (non-separation rate) and the pressure loss, and the non-separation rate, pressure loss, and weight. FIG. This graph shows mullite (3Aρ20
This figure shows the results of a thermal shock test and a pressure drop measurement test performed on molded bodies of 3.2SiO2) with various overlap margins.

The thermal shock test was conducted using the apparatus shown in FIG. A test material 11 is placed on a bottomless cart 10, and the cart 10 is reciprocated on a rail 12. A burner 13 and a blower 14 are installed below this rail 12, and by moving the test material 11 back and forth between the burner 13 and the blower 14 together with the cart 10, the test material 11 is heated by the burner. Cold air cooling is repeated. As a result, the test material 11 undergoes a thermal cycle as shown in FIG. As a result of applying 20 thermal shock cycles to the test material 11 in this way,
The probability that separation of the train wheel train did not occur is shown on the vertical axis of FIG. 3 as the non-separation rate.

On the other hand, the pressure drop measurement test was carried out using the apparatus shown in FIG. That is, the air blower 15 is connected to the duct 17, the rectifying part 16 is provided in the duct 17, and the test material 18 is installed downstream of this rectifying part 16.

Then, the pressure difference between the upstream and downstream sides of the test material 18, that is, the pressure difference before and after the test material 17 passes, is measured,
From this, the pressure loss was determined.

Note that the data in FIG. 3 was obtained for wires with a wire diameter d of 1 dragon and a wire diameter of 8 to 10 ffil+, so d is about 10% of D. Moreover, the weight allowance on the horizontal axis in FIG. 3 is a ratio to the diameter of the wire ring. Therefore, when the weight allowance is approximately 10%, the weight allowance approximately matches the wire diameter d. Further, when the weight allowance is 50%, the coils overlap at a portion that is 1/2 of the diameter of the coil.

As is clear from the curve showing the non-peeling rate in Figure 3,
When the weight allowance is smaller than 10%, that is, when the weight allowance is smaller than the strand diameter d, the non-peeling rate decreases rapidly. Therefore, in the present invention, a weight allowance of 10% or more is ensured.

Next, as shown in FIG. 2(b), the weight should be set to 1/2 or less of the diameter of the wire. Each wire ring 1 is close to circular, but
In reality, it forms a circular shape that is distorted in the arranging direction 4 of the coils or in a direction perpendicular to this arranging direction. Therefore, the diameter of the wire ring 1 varies to some extent depending on the measurement direction, but in the present invention, as shown in the figure, the diameter of the wire wire 1 is set perpendicular to the arrangement direction 4 of the wire wire 1. It is assumed that the measurement was made in the direction. If the weight allowance of the wire ring 1 exceeds 1/2 of the diameter of this line ring 1 (if the weight allowance exceeds 50%), the third
As shown in the figure, the pressure loss increases, impairing the fluidity of the flowing fluid, and increasing the flow resistance. Therefore, in the present invention, the weight difference between adjacent wire wheel trains 2 is set to 1/2 or less of the wire wheel diameter.

In addition, in each train wheel train 2, each train wheel 1 is arranged in its arrangement direction 4.
It is preferable that the coils 1 overlap each other with the wire wheels 1 located before and after. This further increases the ability to prevent peeling, which is preferable in terms of manufacturing and quality.

In addition, by sequentially laminating a wire forming layer composed of a plurality of wire train trains 2 arranged in one plane on a wire forming layer formed in another plane, a predetermined thickness can be achieved. A molded body is obtained. In this case, the thickness of the molded body can be adjusted to a predetermined value by overlapping the upper coil forming layer while each coil forming layer has viscosity.

Furthermore, when stacking the coil forming layers in the thickness direction of the molded body, a coil train 2 consisting of a plurality of coils 1 arranged in one arrangement direction is added.
A first wire forming layer in which a plurality of rows of wire wheels are arranged and a second wire forming layer having wire rows arranged in another arrangement direction substantially orthogonal to this one arrangement direction are alternately laminated. By this,
The directions in which the coils are arranged in the upper layer and the lower layer are substantially orthogonal, and the directionality of the arrangement is eliminated. This makes peeling even more difficult to occur, and there is no need to pay attention to the direction of attachment during actual work, making handling easier.

Next, the characteristics of the case where the linear porous molded body according to the embodiment of the present invention is provided in a flue (Application Example 1) and the case where it is provided in a gutter of a continuous molten metal casting apparatus (Application Example 2) The results of the test will be explained in comparison with the case where a conventional linear porous molded body (see FIG. 7) is applied.

Application example 1 A linear porous molded body made of a mullite or alumina inorganic substance as a breathable solid is installed in the middle of the flue, and hot air at 1100°C and cold air at room temperature are passed through the porous body. A thermal shock test was conducted with alternating flow. As a result, the number of cases where peeling occurred is shown in Table 1 below.

Table 1 However, the test conditions are as follows.

Test piece size: Width: 150 mm, length: 250 mm, thickness: 30 mm Wire diameter: 1.5 mm Weight allowance for example product: 50% Mullite composition: 99% of 3Aρ203 and 2Si02
Alumina composition: Aρ20B of 99% or more, balance 5i0
2, Fe203, Ca ○ The linear porous molded body provided in this flue needs to be replaced every 20 times due to the deterioration of the filtering performance of the molded body itself. In contrast, in the case of the molded article according to the example of the present invention, no peeling occurred during the period of use.

Application Example 2 A linear porous molded body made of an SiC inorganic material was installed in the gutter of a continuous molten metal casting device, and a preheating test was conducted using direct flame from a gas burner. The size of the test material is 300 mm in width and length, 50 mm in thickness, and the preheating end temperature is 120 mm.
0'C. As a result, in the case of the example product of the present invention (Fig. 1), no peeling occurred during 50 preheating tests, whereas in the case of the conventional product (Fig. 7), no peeling occurred during 50 preheating tests. During the test, peeling occurred five times.

[Effects of the Invention] As explained above, according to the present invention, peeling of the surface layer due to sudden thermal shock or local application of external force can be prevented while taking advantage of the characteristics of the linear porous molded body. Therefore, when the porous molded body according to the present invention is applied to filter molten metal, interruption of use due to mechanical destruction can be avoided, and the service life determined by the deterioration of the filtering performance can be completed.

Moreover, since it can withstand sudden thermal shock, the applicable temperature range is widened and the range of uses is expanded.

Furthermore, conversion work due to peeling during use is avoided, improving work efficiency.

As described above, the porous molded article according to the present invention exhibits extremely excellent effects and is extremely useful as a filter or a radiation plate used in fields susceptible to thermal shock.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a porous molded body according to an embodiment of the present invention, FIGS. 2(a) and (b) are schematic plan views for explaining the weight allowance, and FIG. 3 is a non-peeling rate. and a graph showing the relationship between pressure loss and weight allowance, Fig. 4 is a schematic diagram showing the thermal shock test device, Fig. 5 is a graph showing the temperature change pattern of the test material, and Fig. 6 is pressure drop measurement. FIG. 7 is a schematic diagram showing a test apparatus, and a plan view showing a conventional porous molded body. 1: wire wheel, 2: wire wheel row, 3: bare wire, 4: arrangement direction

Claims (4)

[Claims] (1) A plurality of wire rings formed by extruding an inorganic material into a loop shape are arranged in one direction, and these multiple rows of wire rings are arranged on the same plane. A porous molding characterized in that the wire wheels of adjacent wire train rows are overlapped and bonded to each other with a length that is not less than the diameter of the wire but not more than 1/2 of the diameter of the wire. body. (2) The porous molded body according to claim 1, wherein in each wire train train, adjacent wire wheels in the arrangement direction are overlapped and bonded to each other. (3) The porous molded article according to claim 1, characterized in that a plurality of wire ring forming layers obtained by arranging a plurality of wire wheel rows on the same plane are laminated. (4) The porous molded body according to claim 3, wherein the wire ring forming layers that are vertically adjacent to each other have wire arrangement directions substantially orthogonal to each other.