JP5137900B2 - Manufacturing method of gas purification filter - Google Patents

Description

  The present invention relates to a method for manufacturing a gas purification filter, and more particularly to a method for manufacturing a gas purification filter that may be used at high temperatures.

  In many filters used at high temperatures, the occurrence of cracks due to heating becomes a problem. For example, a diesel particulate filter (hereinafter sometimes referred to as “DPF”) that collects particulate matter contained in gas discharged from a diesel engine is used when the collected particulate matter has accumulated to some extent. Then, a regeneration process for burning the particulate matter by self-heating or external heating is performed. At this time, if the temperature distribution in the filter base becomes non-uniform, there is a risk that cracks will occur in the filter base due to thermal stress. And when a crack generate | occur | produces in a filter base | substrate, the particulate matter discharged | emitted with waste gas without being collected by DPF will increase.

  Therefore, a joining type DPF in which a filter base is formed by joining a plurality of segments and thermal stress is mitigated by a sealing material layer between the segments has been proposed (see, for example, Patent Document 1). ing. Here, in the technique of Patent Document 1, a plurality of segments are bonded with a sealing material composed of inorganic fibers, an inorganic binder, an organic binder, and inorganic particles, and the thermal stress generated in each segment is absorbed and relaxed by the sealing material layer. At the same time, the plurality of segments are to be firmly joined by the sealing material layer.

  However, as described above, in the conventional bonded DPF in which a plurality of segments are bonded with a sealing material as described above, it cannot be said that the thermal stress is sufficiently relaxed. As an example, FIG. 8 shows a temperature distribution when a regeneration process is performed after depositing particulate matter on a DPF 100 in which a plurality of segments formed of silicon carbide ceramics are bonded with a silicon carbide sealing material. Show. Here, the DPF 100 used in the measurement was formed into a cylindrical shape having a diameter of 5.66 inches and a length of 10 inches after joining 4 × 4 segments having a cell density of 150 cpsi and a partition wall thickness of 0.4 mm with a sealing material. In the regeneration process, the particulate matter 8g / L is deposited, and after raising the exhaust gas temperature to about 680 ° C, the engine is idling at once and the oxygen supply is increased. This was done by burning particulate matter in a dry environment. FIG. 8 shows the temperature distribution at the time when 30 seconds have elapsed after the start of the regeneration process, and the arrows in the figure show the flow direction of the exhaust gas.

  From FIG. 8, it can be seen that in the DPF 100, the temperature distribution is extremely uneven during the regeneration process. That is, the temperature is extremely high at 900 ° C. or more on the downstream side of the gas flow, and a temperature difference of about 250 ° C. is generated on the upstream end. In addition, the temperature distribution is not uniform in the radial direction, and a temperature difference of about 200 ° C. is generated between the central portion and the peripheral portion of the filter base on the downstream side. As described above, in the junction type DPF in which a plurality of segments are joined, the temperature varies greatly depending on the position of the segment, and the thermal expansion coefficient varies accordingly. In general, the higher the temperature, the greater the difference between the coefficient of thermal expansion of the material constituting the segment and the coefficient of thermal expansion of the sealing material. As a result, in the conventional bonded DPF, a large thermal stress that cannot be relaxed by the sealing material layer is generated, and cracks are often generated.

  Therefore, in view of the above circumstances, the present invention is a gas purification filter that may be used at high temperatures, and is a gas purification filter that is unlikely to crack even if the temperature distribution in the filter base is uneven. It is an object to provide a manufacturing method.

In order to solve the above problems, a method for producing a gas purification filter according to the present invention includes:
“A method for producing a gas purification filter that is disposed in a gas flow path and collects a substance in a gas,
A molding step of forming a plurality of segment molded bodies composed of a plurality of cells partitioned by partition walls extending in a single axial direction by extrusion molding of an unfired ceramic material that becomes a porous body by firing,
An unsintered connecting body formed of a ceramic material and having an axial length shorter than the axial length of the segment molded body is disposed between the plurality of segment molded bodies, and the adjacent segment molded bodies are A pasting step of pasting together with the connector;
The segment molded body and the coupling body bonded together are fired, and the segment molded body and the coupling body are sintered, thereby integrating the segment section and the coupling section having a shorter axial length than the segment section. And a firing step of obtaining a sintered body of the filter main body including the separated filter part in which the connecting part does not exist between the adjacent segment parts.

  As the “ceramic material” constituting the “segment molded body” and the “unfired joined body”, silicon carbide, silicon nitride, cordierite, alumina, and mullite ceramic materials can be used.

  The type of the ceramic material for forming the connected body may be the same as or different from the type of the ceramic material for forming the segment molded body, but it is desirable that the thermal expansion coefficients of both are close. In addition, the segment molded body is “becomes a porous body by firing”, but the connected body may be a porous body or a dense body by firing. If the coupling body is a porous body, the filtering action is exhibited not only by the “segment portion” obtained by sintering the segment molded body but also by the “connection portion” obtained by sintering the coupling body.

  The present invention is characterized in that an unfired coupling body is used whose axial length is shorter than the axial length of the segment molded body, and as a result, a sintered body obtained through a firing step. The axial length of the connecting portion is shorter than the axial length of the segment portion. In this respect, the present invention is greatly different from a conventional filter manufacturing method in which a plurality of segments are bonded together with a sealing material over the entire length in the axial direction as described above.

  In the gas purification filter manufactured according to the present invention having the above-described configuration, each of the plurality of segment portions is only partially connected to the adjacent segment portion. Therefore, in a separation type filter unit in which adjacent segment units are not connected, each segment unit can be expanded and contracted without being restricted by the adjacent segment units. That is, even if the temperature distribution is non-uniform and the thermal expansion coefficient differs for each segment part, the individual segment parts have a high degree of freedom of thermal expansion at their respective thermal expansion coefficients. This suppresses the occurrence of cracks in the filter body due to the difference in thermal expansion coefficient.

  In addition, the present invention is characterized in that a portion connecting a plurality of segment portions is fired to form a sintered body. Also in this respect, a pasty sealing material obtained by mixing an inorganic powder or the like with a binder is applied to the surface of a segment, and after adhering to an adjacent segment, only a drying treatment is performed, and the sealing material layer is not baked. This is different from the manufacturing method of the junction type filter. Here, the reason why the sealing material layer is not baked in the conventional filter manufacturing method is that the thermal stress is intended to be relaxed by the elasticity of the sealing material layer. On the other hand, in the present invention, the thermal stress generated between the segment portions is not relaxed by the connecting portions, but the length of the connecting portions is shortened, and the individual segment portions are made as much as possible according to the respective thermal expansion coefficients. Generation of thermal stress is suppressed by allowing thermal expansion freely. Therefore, even if a connection part is a partial connection, between segment parts needs to be connected firmly.

  Therefore, in the present invention, the segment molded body is bonded with an unfired coupling body and then fired to integrate both portions by sintering, and the coupling portion that is configured to couple the segment portions to the sintered body. did. Here, a ceramic sintered body generally has a higher mechanical strength at room temperature and higher temperature than a ceramic material that is not sintered. Therefore, in the integrated filter part of the gas purification filter manufactured according to the present invention, the plurality of segment parts are firmly integrated via the connecting part, and the form of the filter body as an aggregate of the plurality of segment parts is Easy to hold. Thereby, even if it is the structure where the several segment part is connected only partially, the operation | work which cuts the external shape of a filter main body and the operation | work (canning) which sets a filter main body to a casing can are performed without trouble. be able to.

  Further, in the separation type filter unit, the gas that has flowed into the cell located at the outermost periphery in the segment unit passes through the partition wall and flows through the space between the segment units. Therefore, the gas purification filter manufactured according to the present invention has a filtering function compared to a conventional joining type filter in which adjacent segment portions are bonded with a sealing material and gas cannot flow in the sealing material layer. It has the advantages of high efficiency and low pressure loss.

  In addition, according to the present invention, a plurality of segment portions are only partially connected by a connecting portion that is a sintered body in a simple process of bonding a segment molded body with an unfired connecting body and then firing. Can be obtained.

A method for producing a gas purification filter according to the present invention includes:
"In the pasting step, the adjacent segment molded bodies are pasted together on the end side to be upstream of the gas flow by the connecting body".

  When the gas purification filter is used as a DPF, during the regeneration process, as described above, the segment portion becomes extremely hot at the downstream side of the gas flow compared to the upstream side, and at the downstream side, compared to the upstream side. The temperature distribution tends to be extremely uneven.

  In the present invention, since the segment molded body is bonded by the connecting body on the end side that is upstream of the gas flow, in the manufactured gas purification filter, the segment is formed by connecting the plurality of segment parts at the connecting part. The integral filter part in which the individual expansion and contraction of the part is restricted is formed on the upstream side where the temperature of the segment part is not so high during the regeneration process and the temperature difference between the segment parts is not large. Therefore, the restriction of the free expansion and contraction of the individual segment portions in the integrated filter portion is unlikely to lead to the occurrence of cracks due to thermal stress. On the other hand, the separation type filter unit to which the segment units are not connected is formed on the downstream side where the temperature of the segment unit may become extremely high during the regeneration process, and the temperature difference between the segment units tends to be large. Therefore, the effect | action of this invention that each segment part can be thermally expanded freely according to each thermal expansion coefficient can be acquired more effectively.

A method for producing a gas purification filter according to the present invention includes:
“In the bonding step, the connecting body is arranged so that a space penetrating in the axial direction does not occur between the adjacent segment molded bodies”.

  With the above configuration, in the gas purification filter manufactured according to the present invention, the space between adjacent segments is blocked by the connecting portion, and the space penetrating between the adjacent segment portions from the upstream end portion to the downstream end portion in the filter body. Will not exist. Note that, here, the continuous pores existing in the connection body are not included in the concept of the “space penetrating between the segment portions”.

  Therefore, according to the present invention having the above-described configuration, in the manufactured gas purification filter, it is possible to prevent a situation in which the substance in the gas is discharged outside through the adjacent segment portions without being collected. it can.

The manufacturing method of the gas purification filter according to the present invention includes, in addition to the above configuration,
“In the separation-type filter portion of the filter main body that has undergone the firing step, a non-adhesive filling step of filling a filler between adjacent segments without adhering to the surface of the segment” is provided. be able to.

As is used to form a "non-adhesive material filling layer", "fillers", it can be used sheet over preparative shaped ceramic sintered body, by simply inserting between adjacent segments of the filler “Fill without sticking to the surface of the segment”.

  When the proportion of the separation filter part in the filter body is large, in other words, when the part not connected to other segment parts is long in each segment part, each segment part vibrates when using the gas purification filter. May be easier. On the other hand, in this invention, since the filler is filled between the segment parts of the separation type filter part, the vibration of each segment part is reduced in the manufactured gas purification filter.

  In addition, since the filler is filled without adhering to the surface of the segment part, in the manufactured gas purification filter, the filler can slide relative to the segment part. As a result, the free expansion and contraction of each segment portion is not restricted by the filler, and the effect that the individual segment portions can be freely thermally expanded at a thermal expansion coefficient corresponding to the respective temperature is hindered by the filler. It has never been done.

  As described above, as an effect of the present invention, a gas purification filter that may be used at a high temperature, and a gas purification filter that is unlikely to crack even if the temperature distribution in the filter base is non-uniform. A method can be provided.

(A) Process drawing which shows the manufacturing method of the gas purification filter of one Embodiment of this invention, (b) Process drawing in the case of further providing a non-adhesive material filling process, (c) Process which shows the manufacturing method of other embodiment FIG. And (d) are process diagrams in the case of further including a non-adhesive filling process for the manufacturing method of another embodiment. FIG. 2A is a perspective view of a segment molded body used in the manufacturing method of FIG. 1, and FIG. 2B is a cross-sectional view cut along a plane perpendicular to the axial direction in the vicinity of one end. It is a figure explaining the bonding process of the manufacturing method of FIG. 1A is a plan view of the sintered body of the filter body before performing the outer periphery processing step in the manufacturing method of FIG. 1, viewed from the upstream side, FIG. 1B is a side view, FIG. It is a CC line end view, (e) DD line end view, (f) EE line end view. In the manufacturing method of FIG. 1, (a) a plan view of the sintered body of the filter body after undergoing the peripheral processing step, (b) a plan view from the upstream side, (c) an end view taken along line AA, It is the end elevation cut | disconnected by the surface perpendicular | vertical to a direction, (d) The end elevation which cut | disconnected the separation type filter part by the surface perpendicular | vertical to an axial direction. It is an AA line end elevation of a sintered compact of a filter body after passing a non-adhesive material filling process in a manufacturing method of Drawing 1 (b). It is the end view which cut | disconnected the molded object after passing through the bonding process about the manufacturing method of other embodiment which manufactures the gas purification filter of another structure, and cut | disconnected by the surface parallel to an axial direction through an axial center. It is a figure explaining the temperature distribution at the time of a regeneration process about the conventional junction type diesel particulate filter.

  A gas purification filter manufacturing method (hereinafter simply referred to as “manufacturing method”) according to an embodiment of the present invention will be described below with reference to FIGS. Here, the case where this invention is applied to the manufacturing method of the diesel particulate filter arrange | positioned in the flow path of the gas discharged | emitted from a diesel engine and collecting the particulate matter in gas is illustrated. Although the size of the sintered body is smaller than that of the molded body as a whole due to thermal contraction, such a size difference is not shown in the drawing.

  In the manufacturing method of the present embodiment, as shown mainly in FIG. 1 (a), a segment molded body 10g composed of a plurality of cells 5 partitioned by partition walls 4 extending in a single axial direction Z is arranged. A molding step S1 for forming a plurality of unfired ceramic materials that become a porous body by firing, a plugging step S2 for alternately sealing one end of the cell 5 in each segment formed body 10g, and a plurality of steps Between the segment molded bodies 10g, an unfired coupling body 11g formed of a ceramic material and having a length L in the axial direction Z shorter than the length N in the axial direction Z of the segment molded body 10g is disposed, and adjacent segment molded bodies 10g are disposed. The bonding step S3 for bonding the bonded body 11g, the bonded segment molded body 10g and the unfired linked body 11g are fired, and the segment molded body 10g and the linked body 11g are sintered. The integrated filter part Cf in which the segment part 10 and the connecting part 11 whose axial length is shorter than the segment part 10 are integrated, and the separation type filter part in which no connecting part exists between the adjacent segment parts 10 A firing step S4 for obtaining a sintered body 15 of the filter main body 1a including Sf and an outer shape processing step S5 for processing the outer shape of the sintered body 15 to obtain a columnar filter main body 1a are provided.

  More specifically, in the molding step S1, for example, a square columnar segment molded body 10g as shown in FIG. 2A is molded by extrusion molding. Here, a segment molded body 10g having 18 × 18 cells 5 and having a square cross-sectional shape in a direction perpendicular to the axial direction Z is illustrated.

  Next, in the plugging step S2, for each of the cells 5 arranged in the segment molded body 10g, only one end or the other end of the cell 5 is filled with the plugging material, thereby FIG. As shown in FIG. 5, the sealing portions 6 are formed so that the cells 5 are alternately sealed. Here, FIG. 2B is a cross-sectional view taken along a plane perpendicular to the axial direction Z in the vicinity of one end of the segment molded body 10g.

  In bonding process S3, as shown in FIG. 3, after arrange | positioning nine segment molded bodies 10g 3x3 piece, unfired coupling body 11g is arrange | positioned between adjacent segment molded bodies 10g, and it connects. Adjacent segment molded bodies 10g are bonded together by the body 11g. At this time, the coupling body 11g is stuck so that a space penetrating in the axial direction Z does not occur between the adjacent segment molded bodies 10g.

  Here, since the length L in the axial direction Z of the coupling body 11g is shorter than the length N in the axial direction Z of the segment molded body 10g, the segment molded body 10g is bonded to the entire length in the axial direction Z by the coupling body 11g. Can not. In the present embodiment, the segment molded body 10g is bonded so that one end of the segment molded body 10g and the end of the coupling body 11g coincide with each other. More specifically, in the segment molded body 10g, when the gas purification filter is used, The connecting body 11g is affixed to the end Eu to be the side. As the unfired coupling body 11g, for example, a sheet material formed from a clay-like mixture obtained by mixing a ceramic material of the same quality as the ceramic material used for the segment molded body 10g with a binder is used. be able to.

  In this way, the molded body in which the plurality of segment molded bodies 10g are bonded together with the unfired coupling body 11g is fired in the firing step S4 to obtain the sintered body 15 of the filter body. By this firing step S4, the segment molded body 10g and the unfired coupling body 11g are firmly bonded by sintering. As a result, as shown in FIG. 4, an integrated type in which the segment portion 10 formed by sintering the segment molded body 10g and the connecting portion 11 formed by sintering the connecting body 11g are integrated. The filter part Cf is formed on the end Eu side that should be the upstream side of the gas flow, and the separation type filter part Sf that does not have a connecting part between the adjacent segment parts 10 is the end that should be the downstream side of the gas flow A sintered body 15 of a quadrangular columnar filter body formed on the Ed side is obtained. Thereafter, the outer shape is processed into a cylindrical shape by cutting the sintered body 15 in the outer shape processing step S5.

Further, as shown in FIG. 1 (b), by performing a non-adhesive filling step S6 after the outer shape processing step S5, a filter body 1b further comprising a non-adhesive filling layer 8 is manufactured as shown in FIG. can do. Here, the non-adhesive material filling step S <b> 6 can be a step of simply inserting a filler between adjacent segment portions 10 without adhering to the surface of the segment portion 10. Incidentally, the free thermal expansion of the segment portions 10 to not interfere with the filling material, it is desirable to use a filler sliding properties excellent good abrasion resistance, as such fillers, intersegment portion A ceramic sintered body formed in a sheet shape having a size to be fitted into the space is used .

  In the above, the case where the plugging step S2 is performed subsequent to the molding step S1 has been illustrated, but as shown in FIGS. 1C and 1D, the bonding step S2 ′ subsequent to the molding step S1. After that, the plugging step S3 ′ may be performed.

  By the above manufacturing method, a gas purification filter having the following configuration is obtained. That is, the manufacturing method including steps S1, S2, S3, S4, and S5 shown in FIG. 1A or the manufacturing method including steps S1, S2 ′, S3 ′, S4, and S5 shown in FIG. According to this, as shown in FIG. 5, a plurality of segments each composed of a plurality of cells 5 formed by a porous ceramic sintered body and partitioned by partition walls 4 extending in a single axial direction Z. And a filter main body 1a including a connecting portion 11 that connects adjacent segment portions 10, and the connecting portion 11 is formed of a ceramic sintered body integral with the segment portion 10 and has an axial direction Z. Is shorter than the length N ′ of the segment part 10 in the axial direction Z, and the filter body 1a is adjacent to the integrated filter part Cf in which the adjacent segment parts 10 are connected by the connecting part 11, and adjacent to the filter part 1f. Between segment portion 10 connecting portion 11 is formed from a non-existent separation filter unit Sf.

  In each segment portion 10, one end of each of the plurality of cells 5 is sealed by the sealing portion 6 so that cells opened in one direction and cells opened in the other direction are alternated. When the cells 5 are alternately sealed in this manner, when the gas purification filter is disposed in the gas flow path so that the axial direction Z of the segment portion 10 coincides with the flow direction of the exhaust gas, the exhaust gas is upstream. Since the gas flows in from the cell 5 opened to the cell and flows out from the cell opened in the downstream direction after passing through the porous partition wall 4, when the gas passes through the partition wall 4, Particulate matter is collected.

  The integral filter portion Cf is formed on the end Eu side that should be upstream of the gas flow in the filter body 1a, and the separation filter portion Sf is formed on the end Ed side that should be downstream of the gas flow. Yes. In addition, as shown in FIG. 5C, the connecting portion 11 closes between adjacent segments in the integrated filter portion Cf.

  Further, from the manufacturing method including steps S1, S2, S3, S4, S5, and S6 shown in FIG. 1B, or from steps S1, S2 ′, S3 ′, S4, S5, and S6 shown in FIG. According to this manufacturing method, as shown in FIG. 6 which is an end view corresponding to the end view taken along the line AA, in addition to the above configuration, the segment portion 10 between the segment portions 10 adjacent to each other in the separation type filter portion Sf. The filter main body 1b in which the non-adhesive material filling layer 8 is formed of the filler that is not adhered to the surface can be obtained.

  The filter main bodies 1a and 1b having such a configuration can be installed while covering the outer peripheral surface with a sheet material of an elastic heat-resistant material, and set in the exhaust gas flow passage with the axial direction Z aligned with the exhaust gas flow direction. Thus, it can be used as a DPF for collecting and removing particulate matter from exhaust gas.

  According to the gas purification filter having the above-described configuration manufactured by the manufacturing method of the above-described configuration, each segment portion 10 is freely expanded and contracted without being limited to the adjacent segment portion 10 in the separation filter portion Sf. Therefore, even if the temperature distribution is not uniform, the individual segment portions 10 can be thermally expanded at a coefficient of thermal expansion corresponding to each temperature. Thereby, it can suppress that a crack generate | occur | produces in filter main body 1a, 1b resulting from the difference in a thermal expansion coefficient.

  In addition, since the connecting portion 11 is a sintered body that is firmly integrated with the segment portion 10 by sintering, the filter main body 1a as an aggregate of the plurality of segment portions 10 even if it is partially connected. , 1b is easily maintained.

  In addition, the gas purification filter used as the DPF has an extremely high temperature on the downstream side of the gas flow compared to the upstream side during the regeneration process in which the collected particulate matter is burned and removed. Becomes extremely uneven. In the filter main bodies 1a and 1b, an integrated filter portion Cf in which free expansion and contraction of each segment portion 20 is restricted is provided on the end Eu side that should be upstream of the gas flow, and the end Ed that should be downstream. Since the separation type filter part Sf in which each segment part can freely expand and contract is provided on the side, the effect of relaxing the thermal stress by the free thermal expansion of each segment part 10 can be effectively exhibited. .

  Further, in the separation type filter unit Sf, the gas that has flowed into the cell 5 located at the outermost periphery in the segment unit 10 passes through the partition wall 4 and flows through the space between the segment units 10. Therefore, the filtering efficiency is high and the pressure loss is small.

  Furthermore, in this embodiment, since the space between the adjacent segment parts 10 is obstruct | occluded by the connection part 11, the situation where the particulate matter in waste gas is discharged | emitted outside between the adjacent segment parts 10 is produced. It is prevented. Further, in the filter main body 1b, the non-adhesive material filling layer 8 is provided between the segment portions 10 in the separation type filter portion Sf, so that the vibration of the segment portions 10 is allowed while allowing the individual segment portions 10 to freely expand. Can be suppressed.

  Here, in the filter main bodies 1a and 1b, the length N ′ of the segment part 10 and the length L ′ of the connection part 11 are respectively the length N of the segment molded body 10g and the length L of the unfired connection body 11g. The length is shortened according to the shrinkage rate in the firing step. And if the length L of the connecting body 11g with respect to the length N of the segment forming body 10g is too short, the force for connecting the segment forming body 10g becomes weak, but actually the connecting body 11g with respect to the length N of the segment forming body 10g. When the ratio L / N of the length L was 1/30, it was difficult to bond the segment molded body 10g with the connecting body 11g in the bonding step S3. On the other hand, when the length L of the coupling body 11g is long enough to be equal to the length N of the segment molded body 10g, the individual segment portions 10 are freely heated in the separated filter portions Sf of the manufactured filter bodies 1a and 1b. The effect of expanding is small. Therefore, the ratio L / N is desirably 1/2 or less.

  Further, by manufacturing with different ratios L / N, using a plurality of filter bodies having different ratios L ′ / N ′, holding them in a furnace at a predetermined temperature for 15 minutes, and then cooling them out of the furnace When the thermal shock test was conducted, when the ratio L ′ / N ′ was 1/15 to 2/15, cracks occurred in the closed connection portion 11 due to rapid cooling from the inside of the furnace at 650 to 700 ° C. From this, it can be seen that by setting the ratio L ′ / N ′ within the above range, when an extremely large thermal shock is applied, the coupling portion 11 is cracked by the integrated filter portion Cf, so that the thermal shock can be absorbed. . In addition, even if a crack occurs in the connecting portion 11, when the non-adhesive material filling layer 8 is provided on the downstream side of the connecting portion 11 as in the filter main body 1 b, the non-adhesive material filling layer 8 is particulate. The substance can be collected and the particulate matter can be prevented from being discharged to the outside through the segment portion 10. In other words, it is sufficient that the action of holding the form of the filter main body as an aggregate of the plurality of segment portions 10 by the connecting portion 11 is obtained until the outer shape processing step S5 and the canning operation are completed. That is, in the subsequent use, it is assumed that the non-adhesive material filling layer 8 is appropriately provided and the coating material is appropriately filled between the outer peripheral surface of the filter body and the casing, so that the connecting portion 11 is cracked. In addition, the shape of the filter body can be maintained.

  Therefore, from the above, the ratio L ′ / N ′ is desirably 1/15 to 1/2, and more desirably 1/15 to 2/15. Therefore, when using a ceramic material having the same thermal contraction rate as the material of the segment molded body 10g and the coupling body 11g, the length N of the coupling body 11g with respect to the length N of the segment molded body 10g in the bonding step S3. The ratio L / N is preferably set to 1/15 to 1/2, and more preferably set to 1/15 to 2/15.

  The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various improvements can be made without departing from the scope of the present invention as described below. And design changes are possible.

  For example, in the bonding step S3, the plurality of segment molded bodies 10g are bonded to each other by the connecting body 11g on the end Eu side that should be upstream of the gas flow, so that the manufactured filter mains 1a and 1b However, the present invention is not limited to this, and as shown in FIG. 7 (a), the connecting body 11g is connected to the intermediate portion in the axial direction of the segment molded body 10g. It can also be pasted together. In such a configuration, the separation type filter part Sf is formed on both the end Eu side which is upstream of the gas flow and the end Ed side which is the downstream, and the integral filter is provided in the middle part of the length in the axial direction Z. Part Cf is formed.

  Alternatively, as shown in FIG. 7 (b), in the bonding step S3, the adjacent segment molded body 10g is bonded by the connecting body 11u on the upstream side of the gas flow, and the adjacent segment molded body is also adjacent on the downstream side of the gas flow. 10 g can be bonded together by the coupling body 11d. By such a manufacturing method, a filter main body having a configuration in which both the integrated filter portion Cf and the separation filter portion Sf are provided on one end side is manufactured.

  Moreover, although the case where the segment molded body 10g was a quadrangular prism shape was illustrated above, it is not limited thereto, and may be a triangular prism shape, for example. Moreover, although the case where the external shape of the final filter main body was a column shape was illustrated, it is not limited to this, It can be set as a prismatic column shape or a column shape with an elliptical cross section.

  In addition, in the above, the case where the present invention is applied to a manufacturing method for manufacturing a DPF for purifying gas discharged from a diesel engine is exemplified, but the present invention is not limited to this and is used in other internal combustion engines, steam turbines, and the like. The present invention can be widely applied to a method for manufacturing a gas purification filter that is used, that is, a gas purification filter that may be used at high temperatures.

1a, 1b, 1c, 1d Filter body 4 Partition wall 5 Cell 8 Non-adhesive filling layer 10 Segment portion 10g Segment molded body 11 Connection portion 11g Connection body Cf Integrated filter portion Sf Separable filter portion Eu Becomes upstream of gas flow End portion Ed End portion S1 to be downstream of gas flow Molding step S3, S2 'Pasting step S4 Firing step S6 Non-adhesive filling step

Japanese Patent No. 3121497

Claims (1)

A method for producing a gas purification filter that is disposed in a gas flow path and collects a substance in a gas,
A molding step of forming a plurality of segment molded bodies composed of a plurality of cells partitioned by partition walls extending in a single axial direction by extrusion molding of an unfired ceramic material that becomes a porous body by firing,
An unsintered connecting body formed of a ceramic material and having an axial length shorter than the axial length of the segment molded body is disposed between the plurality of segment molded bodies, and the adjacent segment molded bodies are A pasting step of pasting together with the connector;
The segment molded body and the coupling body bonded together are fired, and the segment molded body and the coupling body are sintered, thereby integrating the segment section and the coupling section having a shorter axial length than the segment section. And a firing step of obtaining a sintered body of a filter main body including a separate filter part including the separated filter part in which the connecting part does not exist between the adjacent segment parts ,
In the bonding step, the adjacent segment molded bodies are bonded to each other on the end side to be upstream of the gas flow by the connecting body, and the connecting body is interposed between the adjacent segment molded bodies in the axial direction. Arranged so that there is no space to penetrate,
In the separation-type filter portion of the filter body that has undergone the firing step, a filler made of a ceramic sintered body formed in a sheet shape between the adjacent segment portions is bonded to the surface of the segment portion. Further comprising a non-adhesive filling process for filling.
A method for producing a gas purification filter , characterized in that :

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