JP5496738B2 - Ceramic tube and manufacturing method thereof - Google Patents

Description

  The present invention relates to a ceramic tube and a manufacturing method thereof, and more particularly to a ceramic tube formed by joining one tubular body and the ends of another tubular body or a solid rod and a manufacturing method thereof.

Conventionally, a linear ceramic tube is generally used as a thermocouple protective tube as described in Patent Document 1, for example.
Patent Document 1 describes a method of manufacturing the linear thermocouple protective tube by forming the linear thermocouple protective tube into a predetermined size by casting mud and then firing it. According to this method, it is relatively easy to manufacture. be able to.
By the way, for example, when a long ceramic tube exceeding the size limit of the mold is necessary, conventionally, a plurality of ceramic tubes are connected as described in Patent Document 2.

As shown in FIG. 8, the ceramic tube connection structure disclosed in Patent Document 2 is formed by inserting the end portions of the first and second ceramic tubes 50a and 50b into the cylindrical sleeve tube 51, respectively. The tubes 50a and 50b are connected to each other.
The sleeve tube 51 is made of a material having a smaller thermal expansion coefficient than the ceramic tubes 50a and 50b. When the connected ceramic tubes 50a and 50b are used as a core tube in a continuous furnace, the ceramic tube 50a expanded by heating. , 50b are tightened by the sleeve tube 51, and the two ceramic tubes 50a, 50b are securely connected.

JP-A-10-67582 Japanese Patent Laid-Open No. 10-148470

By the way, when the two ceramic tubes are connected as described above and the obtained ceramic tube is used as a piping for a fluid such as a liquid or a gas, the airtightness inside the tube needs to be maintained. For this reason, in the connection structure disclosed in Patent Document 2, it is most desirable that the entire inner peripheral surface of the sleeve tube 51 is in close contact with the outer peripheral surfaces of the ceramic tubes 50a and 50b.
However, it is difficult to completely adhere the entire inner peripheral surface of the sleeve tube 51 to the outer peripheral surfaces of the ceramic tubes 50a and 50b. In practice, the adhesiveness becomes non-uniform and the airtightness may be lowered.
A method of using a slurry having the same composition as the ceramic tube as the adhesive on the joint surface of the two ceramic tubes is also conceivable. However, the remaining adhesive layer becomes a porous body, so that airtightness can be maintained. There is a problem that it is insufficient and cannot be used as piping for fluids such as liquid and gas.

  The present invention has been made under the circumstances as described above, and in a ceramic tube formed by joining the ends of one tubular body and another tubular body or a solid rod, and a method for manufacturing the ceramic tube, It is an object of the present invention to provide a ceramic tube that can be bonded to the tube and maintain the airtightness inside the tube, and a method for manufacturing the ceramic tube.

In order to solve the above-described problems, a ceramic tube according to the present invention includes a tubular first long body made of ceramics and a tubular second long body made of ceramics having the same inner diameter as the first long body. A scale body and a cylindrical body made of ceramics disposed in the first long body and the second long body, and annular around the outer periphery of one end of the cylindrical body along the circumferential direction. And a first annular recess that is covered with the first elongated body is formed on the outer periphery of the other end of the cylindrical body, and is annularly formed along the circumferential direction. A second annular recess covered with two elongated bodies is provided, and a connecting portion where the end of the first elongated body and the end of the second elongated body are abutted with each other is the first annular recess and the The cylindrical body is disposed so as to be between the second annular recess, and the first elongated body has an inner periphery on which the first A first annular inward protrusion that fits in the first annular recess and an inner periphery of the second elongated body, and the second annular recess. And a second annular inward protrusion that fits in the second annular recess is provided.
In addition, the angle which the recessed part side wall and the outer peripheral surface of the said cylindrical body make in the pipe-axis direction cross section of said 1st annular recessed part and 2nd annular recessed part is formed in the range of 60 degrees-150 degrees. Is desirable. More preferably, it is 80 ° to 120 °.
Further, a tangent line of the first annular inward projecting portion and the second annular inward projecting portion with the entrance-side corners of the first annular recess and the second annular recess as fulcrums, and the first long It is desirable that the angle formed between the body and the inner peripheral surface of the second long body is in the range of 120 ° to 178 °.

  Thus, the 1st, 2nd elongate body connection part and the cylindrical body which formed the 1st, 2nd annular recessed part were provided, and the 1st, the 2nd elongate body formed in the inner periphery of the 2nd elongate body By fitting the first and second annular protrusions into the first and second annular recesses, the first and second elongated bodies can be firmly joined with high airtightness. Therefore, a ceramic tube having such a configuration can be sufficiently used as a pipe for fluid such as liquid or gas.

Alternatively, in order to solve the above-described problem, a ceramic tube according to the present invention includes a tubular first long body made of ceramics and a tubular first tube made of ceramics having the same inner diameter as the first long body. Two long bodies, and a cylindrical body made of ceramics disposed in the first long body and the second long body, and along the circumferential direction on the outer periphery of one end of the cylindrical body. And is formed in a ring shape along the circumferential direction on the outer periphery of the other end of the cylindrical body. A second annular convex portion that is covered by the second elongated body is provided, and a connecting portion in which the end of the first elongated body and the end of the second elongated body are abutted is the first The cylindrical body is arranged so as to be between the annular convex portion and the second annular convex portion, and the inner circumference of the first elongated body is A first annular outer recessed portion that is formed in an annular shape along the first annular convex portion and fits into the first annular convex portion, and an inner periphery of the second elongated body, The second annular convex portion is formed in an annular shape along the second annular convex portion, and a second annular outwardly recessed portion is provided to be fitted to the second annular convex portion.
The tangent line of the first annular outward depression and the second annular outward depression with the front side corners of the first annular projection and the second annular projection as fulcrums, and the first It is desirable that the angle formed between the annular convex portion and the top surface of the second annular convex portion is in the range of 105 ° to 175 °.

  Thus, the cylindrical body which formed the connection part of the 1st, 2nd elongate body, and the 1st, 2nd annular convex part was provided, and it was formed in the inner periphery of the 1st, 2nd elongate body. By fitting the first and second annular outward depressions to the first and second annular projections, the first and second elongated bodies can be firmly joined with high airtightness. it can. Therefore, a ceramic tube having such a configuration can be sufficiently used as a pipe for fluid such as liquid or gas.

Further, either one of the first elongated body and the second elongated body has a convex taper shape whose outer peripheral surface is tapered, and is joined to the end portion of the convex taper shape. It is desirable that the end of the other elongate body has a concave taper shape in which the inner peripheral surface has an inner diameter that increases toward the tip.
By comprising in this way, since axis alignment becomes easy and reliable, the joining property and airtightness of 1st, 2nd elongate bodies can be improved.

In order to solve the above-described problem, the method for manufacturing a ceramic tube according to the present invention is formed in a tubular shape made of ceramics, and is formed on the outer periphery of one end thereof in an annular shape along the circumferential direction. A cylindrical body having a second annular recess formed annularly in the circumferential direction on the outer periphery of the other end portion, and made of ceramics, and larger than the outer diameter of the cylindrical body a first elongate body having an inner diameter is formed tubular, made of ceramics, a forming step of forming a second elongate body of the tubular formed on the first elongate member and the inner diameter, by the molding process A first firing step of firing the cylindrical body obtained at a predetermined temperature; a calcining step of calcining the first long body and the second long body obtained by the molding step; The cylindrical body sintered in the first firing step is used as the calcining step. Inserted into the calcined body of the first elongated body and the second elongated body obtained by connecting the first elongated body and the calcined body of the second elongated body, the cylindrical body The first elongated body and the second elongated body are covered with a connecting portion, the first annular recess is covered with the first elongated body, and the second annular recess is covered with the second elongated body. It is characterized by including an assembling process for assembling as a cover ceramic tube calcined body and a main firing process for firing the ceramic tube calcined body after the assembling process at a temperature higher than the calcining temperature.

By performing such a process, the inner peripheral surfaces of the first and second elongated bodies are in close contact with the outer peripheral surface of the cylindrical body, and the first and second annular rings provided on the outer periphery of the cylindrical body. The inner circumferences of the first and second elongated bodies bite into the recesses, and the first and second elongated bodies can be fitted into the cylindrical body.
Therefore, it is possible to obtain a ceramic tube with high bondability and airtightness, and it can be sufficiently used as a pipe for fluid such as liquid or gas.

Or in order to solve an above-described subject, the manufacturing method of the ceramic pipe | tube which concerns on this invention is formed in the tubular shape which consists of ceramics, and was formed in the annular | circular shape along the circumferential direction in the one end part outer periphery. A cylindrical body having a second annular convex portion formed annularly along the circumferential direction on the outer periphery of the other end, and ceramics, and from the outer diameter of the cylindrical body a first elongate body tubular inner diameter is large is formed, made of ceramics, a forming step of forming a second elongate body of the tubular formed on the first elongate member and the inner diameter, the forming A first firing step of firing the cylindrical body obtained by the process at a predetermined temperature; a calcining step of calcining the first long body and the second long body obtained by the molding step; The cylindrical body sintered by the first firing step is subjected to the calcination step. Thus, the first elongated body and the second elongated body thus obtained are inserted into the calcined body, the first elongated body and the second elongated body calcined body are connected, and the cylindrical body is The first elongated body and the second elongated body are covered with a connecting portion, the first annular convex portion is covered with the first elongated body, and the second annular convex portion is covered with the second elongated body. And an assembly process for assembling as a ceramic tube calcined body, and a main firing process for firing the ceramic tube calcined body that has undergone the assembly process at a temperature higher than the calcining temperature.

By performing such a process, the first and second annular protrusions provided on the outer periphery of the cylindrical body bite into the inner periphery of the first and second elongated bodies, While the inner peripheral surfaces of the first and second elongated bodies are in close contact with the outer peripheral surface, the first and second elongated bodies can be in a state of being fitted to the cylindrical body.
Therefore, a ceramic tube having high bondability and airtightness can be obtained, and can be sufficiently used as a pipe for fluid such as air or water.

Or in order to solve an above-described subject, the manufacturing method of the ceramic pipe | tube which concerns on this invention is formed in the tubular shape which consists of ceramics, and was formed in the annular | circular shape along the circumferential direction in the one end part outer periphery. A cylindrical body having a second annular recess formed annularly in the circumferential direction on the outer periphery of the other end portion, and made of ceramics, and larger than the outer diameter of the cylindrical body a first elongate body having an inner diameter is formed tubular, made of ceramics, a forming step of forming a second elongate body of the tubular formed on the first elongate member and the inner diameter, by the molding process A calcining step of calcining the obtained cylindrical body at a predetermined temperature and calcining the first long body and the second long body at a temperature lower than the calcining temperature of the cylindrical body. And the cylindrical body obtained by the calcining step with the first elongated body and the second And inserting the first elongated body and the second elongated body into a calcined body, and connecting the cylindrical body with the first elongated body and the second elongated body. An assembly step of covering with a connecting portion, covering the first annular recess with the first elongated body, and covering the second annular recess with the second elongated body, and assembling as a ceramic tube calcined body; and the assembly step And a main firing step of firing the ceramic tube calcined body having undergone the above at a temperature higher than the calcining temperature.

By performing such a process, the shrinkage rate of the first and second elongated bodies is larger than the shrinkage rate of the cylindrical body in the main firing step. For this reason, the inner peripheral surfaces of the first and second elongated bodies are in close contact with the outer peripheral surface of the cylindrical body, and the first and second annular recesses provided on the outer periphery of the cylindrical body have the first The inner circumference of the second elongate body bites into the state where the first and second elongate bodies are fitted into the cylindrical body.
Therefore, it is possible to obtain a ceramic tube with high bondability and airtightness, and it can be sufficiently used as a pipe for fluid such as liquid or gas.

Or in order to solve an above-described subject, the manufacturing method of the ceramic pipe | tube which concerns on this invention is formed in the tubular shape which consists of ceramics, and was formed in the annular | circular shape along the circumferential direction in the one end part outer periphery. A cylindrical body having a second annular convex portion formed annularly along the circumferential direction on the outer periphery of the other end, and ceramics, and from the outer diameter of the cylindrical body a first elongate body tubular inner diameter is large is formed, made of ceramics, a forming step of forming a second elongate body of the tubular formed on the first elongate member and the inner diameter, the forming Temporarily calcining the cylindrical body obtained by the process at a predetermined temperature and calcining the first elongated body and the second elongated body at a temperature lower than the calcining temperature of the cylindrical body. The cylindrical body obtained by the firing process and the calcining process is divided into the first elongated body and the second body. And inserting the first elongated body and the second elongated body into a calcined body, and connecting the cylindrical body with the first elongated body and the second elongated body. An assembly step of covering with a connecting portion, covering the first annular projection with the first elongated body, and covering the second annular projection with the second elongated body, and assembling as a ceramic tube calcined body; And a main firing step of firing the ceramic tube calcined body after the assembly step at a temperature higher than the calcining temperature.

By performing such a process, the shrinkage rate of the first and second elongated bodies is larger than the shrinkage rate of the cylindrical body in the main firing step. For this reason, while the inner peripheral surface of a 1st, 2nd elongate body closely_contact | adheres to the outer peripheral surface of a cylindrical body, the 1st, 2nd annular convex part provided in the outer periphery of a cylindrical body is said 1st. The second elongate body can bite into the inner periphery of the second elongated body and be in close contact with the outer peripheral surface of the cylindrical body, and the first and second elongated bodies can be fitted into the tubular body.
Therefore, it is possible to obtain a ceramic tube with high bondability and airtightness, and it can be sufficiently used as a pipe for fluid such as liquid or gas.

In the assembling process of the calcined body, an average particle size of 100 nm or less is formed between the cylindrical body, the first long body, and the second long body, and the first long body, the second long body, It is desirable to use, as an adhesive, a slurry containing 10% or more of powder having the same composition as the long and cylindrical bodies.
As described above, by using an adhesive on the joining surface or the like, the joining property and the airtightness can be improved.

  According to the present invention, in a ceramic tube formed by bonding ends of one tubular body and another tubular body, and a manufacturing method thereof, ceramic that can be reliably bonded and the airtightness inside the tube can be maintained. A tube and its manufacturing method can be obtained.

FIG. 1 is a partially broken plan view showing a first embodiment of a ceramic tube of the present invention. FIG. 2 is a view for explaining a state in which each member constituting the ceramic tube of FIG. 1 is assembled and manufactured. FIG. 3 is a partially enlarged view (sectional view) of the ceramic tube of FIG. FIG. 4 is a partially broken plan view showing a second embodiment of the ceramic tube of the present invention. FIG. 5 is a view for explaining a state in which the respective members constituting the ceramic tube of FIG. 4 are assembled and manufactured. 6 is a partially enlarged view (cross-sectional view) of the ceramic tube of FIG. FIG. 7 is a view showing a modification of the ceramic tube of the present invention. FIG. 8 is a diagram for explaining a conventional method of connecting ceramic tubes.

  Hereinafter, a first embodiment of a ceramic tube and a manufacturing method thereof according to the present invention will be described with reference to the drawings. FIG. 1 is a partially broken plan view showing a first embodiment of a ceramic tube of the present invention. FIG. 2 is a view for explaining a state in which each member constituting the ceramic tube of FIG. 1 is assembled and manufactured. FIG. 3 is a partially enlarged view (sectional view) of the ceramic tube of FIG.

The ceramic tube 1 shown in FIG. 1 is obtained by assembling a plurality of members shown in FIG. 2A as shown in FIG. 2B and then obtaining a sintered body shown in FIG. be able to.
That is, the ceramic tube 1 includes a tubular first long body 2 (hereinafter referred to as “tube member 2”) and a tubular second long body 3 (hereinafter referred to as “tube member 2”) extending along the axis of the tube. Tube member 3 ") and a cylindrical body 4 for reliably joining them into one tube. The tube member 2, the tube member 3, and the cylindrical body 4 are each formed of ceramics. More specifically, the tube members 2 and 3 have substantially the same inner and outer diameters, and the inner diameters of the tube members 2 and 3 are formed larger than the outer diameter of the tubular body 4. As shown in the figure, the one end 2 a of the tube member 2 and the one end 3 a of the tube member 3 are coaxially butted and connected to each other, and the tubular body 4 is disposed in the tube member 2 and the tube member 3. .

  The cylindrical body 4 has a first annular recess 4B (hereinafter referred to as “annular recess 4B”) and a second groove, which are grooves having a square cross section along the circumferential direction, on the outer periphery close to the end portions 4A and 4a, respectively. The annular recess 4b (hereinafter referred to as "annular recess 4b") is formed, and the connecting portion 1a between the tube member 2 and the tube member 3 is disposed between the annular recess 4B and the annular recess 4b. Has been. Due to the shrinkage of the tube member 2 and the tube member 3 in the main firing step, the peripheral surfaces of the tube member 2 and the tube member 3 are deformed and bite into the annular recess 4B and the annular recess 4b as shown in FIG. . That is, the ceramic tube 1 obtained as a sintered body is formed so as to project annularly on the inner peripheral surface side of the tube member 2 and the tube member 3 with respect to the annular recess 4B and the annular recess 4b of the tubular body 4. The first annular inward protrusion 5 (hereinafter referred to as “annular protrusion 5”) and the second annular inward protrusion 6 (hereinafter referred to as “annular protrusion 6”) are fitted. It is in a state.

  If it demonstrates in detail, the cyclic | annular protrusion part 5 (6) of the pipe member 2 (3) will be continuously formed along the formation direction (circumferential direction) of the cyclic | annular recessed part 4B (4b) in the cylindrical body 4. FIG. As shown in the cross-sectional view in the tube axis direction of FIG. 3, the pipe member 2 (3) is inserted into the annular recess 4 B (4 b) starting from the pair of inlet side corners 4 C (4 c) of the annular recess 4 B (4 b). The peripheral surface bites in and the side surface 5a (6a) of the annular protrusion 5 (6) is formed in the annular recess 4B (4b).

If the cross section angle θ1 of the inlet side corner portion 4C (4c), which is the angle formed by the recess side wall in the cross section in the tube axis direction of the annular recess 4B (4b) and the outer peripheral surface of the cylindrical body 4, is too acute, the tube member When the second and third peripheral surfaces are deformed and bite in, the corner 4C (4c) may be lost. On the other hand, if the obtuse angle is too large, the surface that comes into contact with the peripheral surfaces of the pipe members 2 and 3 that bite in becomes large, the joint portion becomes uneven, and the airtightness may be lowered. Therefore, the cross-sectional angle θ1 in the tube axis direction of the corner 4C (4c) shown in FIG. 3 is preferably in the range of 60 ° ≦ θ1 ≦ 150 °.
In order to obtain high airtightness, the tangent line of the annular protrusion 5 (6) with the inlet side corner 4C (4c) of the annular recess 4B (4b) as a fulcrum and the inner circumference of the pipe member 2 (3) The angle θ2 (cross-sectional angle in the tube axis direction) formed with the surface is preferably in the range of 120 ° ≦ θ2 ≦ 178 °.

In the manufacturing method of the ceramic tube according to the first embodiment of the present invention, the molded body of the tube member 2, the tube member 3, and the cylindrical body 4 is manufactured, and the cylindrical body 4 is fired (first firing). ) Or calcining, and the molded body of the tube member 2 and the tube member 3 is calcined at a firing temperature of the tubular body 4 or a temperature lower than the calcining temperature.
In addition, the molded object of the pipe member 2, the pipe member 3, and the cylindrical body 4 can be manufactured by the method of manufacturing a general ceramic molded body.
For example, 100 parts by weight of an alumina raw material powder having an average particle size of 0.5 μm (maximum particle size 2 μm, minimum particle size 0.1 μm), 20 parts by weight of ion-exchanged water, a small amount of ammonium polyacrylate as a dispersant, and a binder A slurry is prepared by mixing 1 part by weight of polyvinyl alcohol with a pot mill.

The obtained slurry is granulated using a spray dryer, and the obtained granulated powder is formed into a cylindrical body (for example, outer diameter φ14.3 mm, inner diameter φ10 using a CIP at a pressure of 2 ton / cm 2. .8 mm, length 48 mm). Here, annular recesses 4B and 4b (for example, a width of 0.8 mm and a depth of 0.3 mm) are respectively provided along the circumferential direction at positions of predetermined dimensions (for example, 8 mm) from the tips of the end portions 4A and 4a of the cylindrical body. Is provided.
Similarly, the obtained slurry is granulated using a spray dryer, and the obtained granulated powder is obtained using CIP with an inner diameter larger than the outer diameter of the cylindrical body at a pressure of 2 ton / cm 2. And two linear tube members having the same outer diameter (for example, outer diameter φ18.5 mm, inner diameter φ14.5 mm, length 60 mm).

Subsequently, each of the cylindrical bodies is preferably fired in the atmosphere at a temperature of 1800 ° C. to 1900 ° C., and the two tubular member molded bodies are preferably calcined at 800 ° C. to 900 ° C. .
Alternatively, the molded body of the tubular body is preferably calcined at a temperature of preferably 1100 ° C. to 1200 ° C., and the molded body of the two pipe members is lower than the calcining temperature of the cylindrical body, Is calcined at 800 ° C to 900 ° C.
Then, the one end 2a of the obtained tube member 2 and the one end 3a of the tube member 3 are abutted against each other and inserted into the calcined body of the cylindrical body 4 in a state of being connected to one tube, and the cylindrical body 4 The annular recess 4B is covered with the tube member 2, and the annular recess 4b of the cylindrical body 4 is covered with the tube member 3, and assembled as a ceramic tube calcined body.
At this time, the inlet-side corner 4C of the annular recess 4B and the inlet-side corner 4c of the annular recess 4b are R-chamfered or C-chamfered, and the chamfered surface and at least the tube member in contact with the chamfered surface The inner surface portion is preferably machined to Ra ≦ 5 μm. More preferably, Ra ≦ 2 μm or less. As a result, the degree of adhesion between the inner peripheral surface of the pipe member and the inlet side corner of the annular recess can be further increased, and the possibility of damage to the pipe member and the inlet side corner due to firing can be further reduced. .
Further, during this assembly, in the main firing, in order to more reliably join and improve the airtightness, the connecting portion between the tube member 2 and the tube member 3, and the tubular body 4 and the tube member 2 and the tube member 3 It is preferable that a slurry having an average particle diameter of 100 nm containing 10% or more of the same material (same composition) as each member to be bonded is interposed as an adhesive in the joint portion.

Thereafter, the assembled ceramic tube calcined body is subjected to main firing at a temperature higher than the calcining temperature, for example, 1800 ° C. in the atmosphere.
In addition, since the molded body of the tube member 2 and the tube member 3 is calcined at a temperature lower than the calcining temperature of the tubular body 4 as described above, in this main firing step, the tube member 2 and the tube member 3 are calcined. The contraction amount of the cylinder body 4 becomes larger than the contraction amount of the cylindrical body 4.
As a result, the pipe member 2 and the pipe member 3 contract more greatly, and the peripheral surfaces thereof are brought into close contact with the outer peripheral surface of the cylindrical body 4 and are deformed so as to bite along the annular recesses 4B and 4b.
Therefore, after this main firing, the ceramic tube 1 in a state where the annular protrusions 5 and 6 formed in the tube member 2 and the tube member 3 are fitted in the annular recess 4B and the annular recess 4b of the cylindrical body 4. Is obtained.

As described above, according to the first embodiment of the present invention, in the ceramic tube 1 obtained as a sintered body, the annular member 4B and the annular recess 4b of the tubular member 4 are provided with the tube member 2 and the tube member. The annular projecting portion 5 and the annular projecting portion 6 formed in 3 are fitted together, and the tube member 2 and the tube member 3 can be firmly joined with high airtightness.
Therefore, it is possible to obtain the ceramic tube 1 having high bondability and high airtightness, and it can be sufficiently used as piping for fluid such as liquid or gas.

  Then, 2nd embodiment which concerns on the ceramic pipe | tube of this invention and its manufacturing method is described. FIG. 4 is a partially broken plan view showing a second embodiment of the ceramic tube of the present invention. FIG. 5 is a view for explaining a state in which the respective members constituting the ceramic tube of FIG. 4 are assembled and manufactured. 6 is a partially enlarged view (cross-sectional view) of the ceramic tube of FIG.

The ceramic tube 10 shown in FIG. 4 is a fired body shown in FIG. 5C after assembling a plurality of calcined members shown in FIG. 5A as shown in FIG. Can be obtained.
That is, the ceramic tube 10 includes a tubular first long body 12 (hereinafter referred to as “tube member 12”) and a tubular second long body 13 (hereinafter referred to as “tube member 12”) extending along the axis of the tube. Tube member 13 ") and a cylindrical body 14 for reliably joining them into one tube. The tube member 12, the tube member 13, and the cylindrical body 14 are each formed of ceramics. More specifically, the pipe member 12 and the pipe member 13 have the same inner and outer diameters, and the inner diameters of the pipe member 12 and the pipe member 13 are formed larger than the outer diameter of the cylindrical body 14. As shown in the drawing, one end portion 12 a of the tube member 12 and one end portion 13 a of the tube member 13 are abutted and connected on the same axis, and the tubular body 14 is disposed in the tube member 12 and the tube member 13. .

  The cylindrical body 14 is formed with an annular protrusion 14B and an annular protrusion 14b extending in the circumferential direction on the outer periphery close to the end 14A and the end 14a, respectively, in which the cross section in the tube axis direction is a square projecting outward. The connecting portion 10a between the tube member 12 and the tube member 13 is disposed between the annular convex portion 14B and the annular convex portion 14b. The inner diameters of the tube member 12 and the tube member 13 are formed larger than the outer diameter of the cylindrical body 14 including the heights of the annular convex portion 14B and the annular convex portion 14b. As shown in FIG. 5B, before the main firing, the annular convex portion 14B and the annular convex portion 14b are covered by the tube member 12 and the tubular member 13, and therefore, after the main firing, the tubular member is formed as shown in FIG. 12. Due to the contraction of the tube member 13, the circumferential surface of the tubular member 12 is deformed into the annular convex portion 14B of the tubular body 14, and the annular convex portion 14b of the tubular body 14 is deformed into the circumferential surface of the tubular member 13. It is in a state (further, the inner peripheral surfaces of the tube member 12 and the tube member 13 are in close contact with the outer peripheral surface of the cylindrical body 14). Further, the tubular protrusions 14B and the annular protrusions 14b of the cylindrical body 14 are fitted in a state where the inner peripheral surfaces of the tube member 12 and the tube member 13 are covered.

That is, in the tube member 12 and the tube member 13 after the main firing, the section in the tube axis direction is an annular convex portion as shown in FIG. 6 at a portion in contact with the annular convex portion 14B and the annular convex portion 14b of the cylindrical body 14. 14B, an annular outwardly recessed part 15 (hereinafter referred to as “annularly recessed part 15”) and an annular outwardly recessed part 16 (hereinafter referred to as “annularly recessed part 16”) that are deformed and fitted into a concave shape with respect to the annular convex part 14b. Is formed in an annular shape along the circumferential direction.
Here, in order to obtain high airtightness, the tangent line of the annular depression 15 (16) with the tip side corner 14C (14c) of the annular projection 14B (14b) as a fulcrum, and the annular projection 14B ( The angle θ3 (cross-sectional angle in the tube axis direction) formed with the top surface of 14b) is preferably in the range of 105 ° ≦ θ3 ≦ 175 °.

  Thus, after the main firing, the annular convex portion 14B of the cylindrical body 14 bites into the inner peripheral surface of the tube member 12, and the annular convex portion 14b of the cylindrical body 14 bites into the pipe member 13 into the inner peripheral surface. The annular projections 14B and 14b are covered with the annular depressions 15 and 16 of the pipe members 12 and 13, respectively, and are brought into a fitted state. As a result, the two pipe members 12 and 13 are reliably connected, and one ceramic pipe 10 having high airtightness is obtained.

When this ceramic tube 10 is manufactured, the molded body of the tube members 12 and 13 and the molded body of the cylindrical body 14 are manufactured in the same manner as in the first embodiment (ceramic tube 1). The body 14 is fired or calcined, and the molded bodies of the tube members 12 and 13 are calcined at a temperature lower than the firing temperature or calcining temperature of the tubular body 14.
And the obtained calcined body is assembled and main baking is performed at a temperature higher than the calcining temperature.
That is, in this main firing, the tube member 12 and the tube member 13 contract more greatly than the tubular body 14 due to the difference in the calcining temperature, and the annular convex portion 14B of the tubular body 14 is the annular depressed portion 15 of the tube member 12. In addition, the ceramic tube 10 is obtained in a state in which the annular protrusions 14 b are respectively fitted in the annular depressions 16 of the tube member 13.

As described above, according to the second embodiment, in the ceramic tube 10 obtained as a sintered body, the annular depressed portions 15 of the tubular members 12 and 13 are formed with respect to the annular convex portions 14B and 14b of the tubular body 14. 16 will be in the state each fitted, and the pipe members 12 and 13 can be firmly joined with high airtightness.
Therefore, the ceramic tube 10 having high bondability and airtightness can be obtained, and can be sufficiently used as a pipe for fluid such as air or water.

  Moreover, in the said embodiment, although what provided one cyclic | annular recessed part 4B (4b) or the cyclic | annular convex part 14B (14b) on the surrounding surface of the cylindrical body was shown, two or more are shown in the cylindrical body. You may comprise so that an annular recessed part or an annular convex part may be provided and they may be covered with a cylindrical body.

Moreover, in said 1st, 2nd embodiment, although the edge part shape used as the joining surface of pipe members was shown as a surface orthogonal to a pipe axis, in this invention, it is limited to the form. Is not to be done.
For example, as shown in FIG. 7 as a modification of the first embodiment, the outer peripheral surface 7 of one end of the tube member 2 (or the tube member 3) is tapered and the other tube member 3 (or the tube) The inner peripheral surface 8 of the end portion of the member 2) may be tapered so that the inner diameter increases toward the tip.
By forming in such a manner, in the assembly work after calcination, the work of connecting the pipe members 2 and 3 coaxially becomes easy, and the airtightness inside the pipe can be improved.

In the first and second embodiments, the annular concave portion 4B (4b) or the annular convex portion 14B (14b) provided on the outer peripheral surface of the cylindrical body is formed along the circumferential direction thereof. However, the present invention is not limited to this form.
For example, as a modification of the first embodiment, annular recesses 4B and 4b (or annular projections) formed on the outer peripheral surface of the cylindrical body 4 are provided in a state inclined at a predetermined angle with respect to the circumferential direction and the axial direction. May be.
Or you may provide the annular recessed part 4B, 4b (or annular convex part) formed in the outer peripheral surface of the cylindrical body 4 in zigzag shape, S shape, etc. along the circumferential direction of a pipe | tube.
Furthermore, in said 1st, 2nd embodiment, both annular recessed part 4B (4b) or annular convex part 14B (14b) provided in the outer peripheral surface of a cylindrical body is annular recessed part, or both are annular convex. However, in the present invention, one may be an annular concave portion and the other may be an annular convex portion.

In the above embodiment, the outer diameters of the tube members 2 and 3 (or the tube members 12 and 13) are substantially the same. However, the ceramic tube of the present invention is not limited thereto. .
For example, if the inner diameters of the tube members 2 and 3 (12, 13) are substantially the same, the tube members 4 (14) can be reliably coupled to each other, so that the outer diameters thereof are different. It doesn't matter.
Alternatively, even if the inner diameters of the pipe members 2 and 3 (12 and 13) are different, it is sufficient that the cylindrical body 4 (14) has an outer diameter corresponding to these different inner diameters. Tube members can be joined together while maintaining airtightness.

  The ceramic tube and the manufacturing method thereof according to the present invention will be further described based on examples. In this example, a ceramic tube was manufactured according to the above embodiment, and the effect of the present invention was verified.

[Example 1]
In Example 1, an alumina raw material was used, a cylindrical body having an outer diameter of 14.3 mm, an inner diameter of 10.8 mm, and a length of 48 mm, and two pipe members having an outer diameter of 18.5 mm, an inner diameter of 14.5 mm, and a length of 60 mm And molded.
In addition, each edge part used as the joint surface of the said 2 pipe member was taper-processed in convex shape and concave shape, respectively so that it might have a 12 degree inclination with respect to an axial direction.
In the cylindrical body, annular recesses (grooves) having a width of 0.8 mm and a depth of 0.3 mm were formed annularly along the circumferential direction at positions of 8 mm from the end portions of the outer peripheral surface in the vicinity of both ends.
Next, the cylindrical body was fired at 1800 ° C., and two pipe members were calcined at 900 ° C. lower than the firing temperature of the cylindrical body.
Thus, when assembling each member fired and calcined, alumina fine particles having an average particle diameter of 80 nm and pure water are mixed at a ratio of 1: 1 at the joint portion of the two pipe members and the outer peripheral surface of the cylindrical body. The kneaded slurry was applied.
Thereafter, the assembled ceramic tube calcined body was air-fired at 1800 ° C. to obtain a sintered body of the ceramic tube.

One end of the sintered body of the obtained ceramic tube was sealed, and the other was installed in a leak measuring machine, and the amount of leak was measured. As a result, it was confirmed that the leak amount was 0.0042 Lusec (Lussec), and it was confirmed that the leak amount was sufficiently usable as piping for air, water, and the like.
Moreover, in the obtained ceramic tube, the outer diameter in the longitudinal direction of the tube member was 17.4 mm to 17.8 mm, and a variation of 2.3% occurred. From this result, it was estimated that the tube member bite into the annular recess of the cylindrical body by the main firing.
Further, a plurality of actually obtained ceramic tubes were cut in the tube axis direction, and 10 cross sections near the annular recess of the cylindrical body were observed. As a result, it was confirmed that the inner peripheral surface of the tubular member had digged into the annular recess of the cylindrical body, and the hollow section cross-sectional area of the annular recess was an average value in the range of 15% to 33% of the original cross-sectional area. It decreased by 25%. The angle θ2 formed between the tangent line of the annular inward projecting portion with the inlet side corner of the annular recess as a fulcrum and the inner peripheral surface of the pipe member was an average value of 142 ° in the range of 135 ° to 145 °. .

[Example 2]
In Example 2, an alumina raw material was used to form two pipe members having an outer diameter of 19 mm, an inner diameter of 15 mm, and a length of 60 mm, and a cylindrical body having an outer diameter of 14.2 mm, an inner diameter of 11.5 mm, and a length of 45 mm. .
In addition, each end portion serving as a joining surface of the two pipe members was tapered into a convex shape and a concave shape so as to have an inclination of 12 ° with respect to the axial direction.
Also, on the cylindrical body, annular convex portions (width 0.8 mm, height 0.3 mm) having a square cross section in the tube axis direction at positions of 7 mm from both ends in the vicinity of both ends along the circumferential direction. Formed. In the tube member, the outer diameter of the portion where the annular convex portion is formed is 14.8 mm, and the other outer diameter is 14.2 mm.
Next, the cylindrical body was fired at 1800 ° C., and two pipe members were calcined at 900 ° C. lower than the firing temperature of the cylindrical body.
Thus, when assembling each member fired and calcined, alumina fine particles having an average particle diameter of 80 nm and pure water are mixed at a ratio of 1: 1 at the joint portion of the two pipe members and the outer peripheral surface of the cylindrical body. The kneaded slurry was applied. Thereafter, the assembled ceramic tube calcined body was fired at 1800 ° C. in the air.

One end of the sintered body of the obtained ceramic tube was sealed, and the other was installed in a leak measuring machine, and the amount of leak was measured. As a result, the leak amount was confirmed to be 0.0049 Lusec (Lussec), and it was confirmed that the leak amount could be sufficiently used as piping for air, water and the like.
Moreover, the outer diameter in the longitudinal direction of the tube member of the obtained ceramic tube was 17.7 mm to 18.3 mm, and a variation of 3.4% occurred. From this result, it was estimated that the annular convex portion of the cylindrical body bites into the inner peripheral surface of the pipe member by the main firing.
Further, a plurality of ceramic tube sintered bodies actually obtained were cut in the tube axis direction, and the cross section of the annular convex portion of the cylindrical body was observed at 10 points. As a result, it was confirmed that the annular convex portion of the cylindrical body bites into the inner peripheral surface of the pipe member. Note that the angle θ3 formed between the tangent to the annular outwardly recessed portion with the tip side corner of the annular convex portion as a fulcrum and the top surface of the annular convex portion is in the range of 165 ° to 175 °, and the average value is 168 °. It was.

Example 3
In Example 3, an annular recess having a width of 0.5 mm and a depth of 0.2 mm, which is inclined by 60 ° with respect to the axial direction, is formed on the circumferential surface of a cylindrical body having a predetermined size from the tip of the end portion, which is covered with a pipe member. did.
Other conditions were formed in the same manner as the sample used in Example 1, and a sintered body of a ceramic tube was obtained by air firing at 1800 ° C.
As a result of measuring the amount of leakage with respect to the obtained sintered body of the ceramic tube, it was 0.0061 Lusec (Lussec), compared with the case where the formation direction of the annular recess is orthogonal to the tube axis direction (Example 1). However, the result was inferior.
In addition, when a plurality of the annular recesses are formed in parallel in the circumferential direction on the peripheral surface of the cylindrical body covered with the pipe member, or when the annular recesses are formed in a zigzag shape, or the annular recess and the annular protrusion The amount of leakage was measured also when the part was mixed in parallel, or when the annular convex part was formed in a zigzag manner, but the value was not inferior.

Example 4
In Example 4, the angle θ1 shown in FIG. 3 (the angle formed between the side wall of the concave portion in the cross section in the tube axis direction of the annular recess and the outer peripheral surface of the cylindrical body), the angle θ2 (the outer peripheral surface of the cylindrical body 4 and the annular concave portion). The cross section angle in the tube axis direction formed by the tangent of the annular protrusion 5 (6) with respect to the inlet side corner 4C (4c) of 4B (4b) was changed, and the most suitable range for suppressing the leak amount was examined. . The angle θ1 was 15 ° from 45 ° to 180 °, and the angle θ2 was 110 ° to 180 °. Each sample was prepared under the conditions shown in Table 2, and the leak amount was measured for each sample. Other conditions were the same as in the sample used in Example 1.
Table 1 shows the determination results for the angle θ1 and the angle θ2 obtained as a result of the measurement. In the determination results in the table, “O” indicates that the leak amount is 0.01 Lusec (Lussec) or less, and “Δ” indicates that the leak amount is greater than 0.01 Lusec and is less than 0.1 Lusec. , “×” indicates that the amount of leakage is not greater than 0.1 Lusec, and “XX” indicates that chipping occurs in 4C (4c), and that “−” cannot be theoretically produced.

  As shown in Table 1, it was confirmed that the range of the angle θ1 that can sufficiently suppress the leak amount is a range of 60 ° to 150 °, and the range of the angle θ2 is a range of 120 ° to 178 °. Moreover, as a result of observing the axial direction cross section of the sample in those angle ranges, it was confirmed that the inner peripheral surface of the pipe member bites into the annular recess surely.

Example 5
In Example 5, the angle θ3 shown in FIG. 6 (the top surface of the annular protrusion 14B (14b) and the annular recess 15 (16) with respect to the tip side corner 14C (14c) of the annular protrusion 14B (14b) are provided. We examined the most suitable range for reducing the amount of leakage by changing the cross-sectional angle in the tube axis direction with the tangent line. Each sample was created under the conditions shown in Table 3 for the angle θ3 from 90 ° to 180 °, and the leak amount was measured for each sample. Other conditions were the same as in the sample used in Example 2.
Table 2 shows the leak amount with respect to the angle θ3 obtained as a result of the measurement and the determination result. In the determination results in the table, “O” indicates that the leak amount is 0.01 Lusec (Lussec) or less, and “Δ” indicates that the leak amount is greater than 0.01 Lusec and is less than 0.1 Lusec. , “×” indicates that the leak amount is more than 0.1Lusec (Lussec).

  As shown in Table 2, it was confirmed that the range of the angle θ3 that can sufficiently suppress the leak amount is a range of 105 ° to 175 °. Moreover, as a result of observing the axial direction cross section of the sample in those angle ranges, it was confirmed that the peripheral surface of the pipe member bites between the two annular convex portions.

DESCRIPTION OF SYMBOLS 1 Ceramics tube 1a Connection part 2 Tube member (1st elongate body)
2a End 3 Tube member (second long body)
3a end 4 cylindrical body 4A end 4a end 4B annular recess (first annular recess)
4b annular recess (second annular recess)
5 annular protrusion (first annular inward protrusion)
6 annular projection (second annular inward projection)
DESCRIPTION OF SYMBOLS 10 Ceramic tube 10a Connection part 12 Tube member (1st elongate body)
12a End 13 Tube member (second long body)
13a end part 14 cylindrical body 14B annular convex part (first annular convex part)
14b Annular convex part (second annular convex part)
15 annular depression (first annular outward depression)
16 annular depression (second annular outward depression)

Claims (11)

A tubular first elongated body made of ceramics;
A tubular second elongated body made of ceramics having the same inner diameter as the first elongated body,
A cylindrical body made of ceramics arranged in the first long body and the second long body,
On the outer peripheral surface of one end of the cylindrical body, a first annular recess is provided that is annularly formed along the circumferential direction and is covered by the first elongated body,
A second annular recess is provided on the outer peripheral surface of the other end of the cylindrical body, and is formed in an annular shape along the circumferential direction, and is covered with the second elongated body,
The cylindrical body so that the connecting portion where the end of the first elongated body and the end of the second elongated body are abutted is between the first annular recess and the second annular recess. And place
A first annular inward projection formed on the inner peripheral surface of the first elongated body along the first annular recess and fitted into the first annular recess; and A second annular inward protruding portion that is annularly formed along the second annular recess and fitted into the second annular recess is provided on the inner peripheral surface of the two elongated bodies. Ceramic tube characterized by   The angle formed by the side wall of the recess in the cross section in the tube axis direction of the first annular recess and the second annular recess and the outer peripheral surface of the cylindrical body is formed within a range of 60 ° to 150 °. The ceramic tube according to claim 1.   Tangent lines of the first annular inward projection and the second annular inward projection with the entrance-side corners of the first annular recess and the second annular recess as fulcrums, the first elongated body, The ceramic tube according to claim 1 or 2, wherein an angle formed with an inner peripheral surface of the second elongated body is formed within a range of 120 ° to 178 °. A tubular first elongated body made of ceramics;
A tubular second elongated body made of ceramics having the same inner diameter as the first elongated body,
A cylindrical body made of ceramics arranged in the first long body and the second long body,
On the outer peripheral surface of one end of the cylindrical body, a first annular convex portion that is formed in an annular shape along the circumferential direction and is covered with the first elongated body is provided,
A second annular convex portion is provided on the outer peripheral surface of the other end portion of the cylindrical body, and is formed in an annular shape along the circumferential direction, and is covered with the second elongated body,
The tube so that the connecting portion where the end of the first elongate body and the end of the second elongate body abut each other is between the first annular convex portion and the second annular convex portion. Place the body,
A first annular outward recess formed on the inner peripheral surface of the first elongate body along the first annular protrusion and fitted into the first annular protrusion; and Provided on the inner peripheral surface of the second elongate body is a second annular outward recessed portion that is annularly formed along the second annular convex portion and fits into the second annular convex portion. Ceramic tube characterized by being made.   A tangent line of the first annular outer recessed portion and the second annular outer recessed portion with the first side annular convex portion and the tip side corner portion of the second annular convex portion as a fulcrum, and the first annular convex portion. 5. The ceramic tube according to claim 4, wherein an angle formed between the convex portion and the top surface of the second annular convex portion is formed within a range of 105 ° to 175 °. Either one end of the first elongated body and the second elongated body has a convex taper shape whose outer peripheral surface is tapered,
The end portion of the other elongated body joined to the end portion of the convex taper shape is a concave taper shape in which an inner peripheral surface thereof increases in inner diameter toward the tip end. 5. The ceramic tube described in any one of 5 above. It is formed in a tubular shape made of ceramics and has a first annular recess formed in an annular shape along the circumferential direction on the outer periphery of one end thereof, and formed in an annular shape along the circumferential direction on the outer periphery of the other end. a cylindrical body having a second annular recess which is made of ceramic, a first long body tubular inner diameter larger than the outer diameter of the tubular body is formed, made of ceramic, said first long A molding step for forming a tubular second elongated body having the same inner diameter as the scale body;
A first firing step of firing the cylindrical body obtained by the molding step at a predetermined temperature;
A calcining step of calcining the first elongated body and the second elongated body obtained by the molding step;
The cylindrical body sintered in the first firing step is inserted into the calcined body of the first long body and the second long body obtained in the calcining step, and the first long body And the calcined body of the second long body, the cylindrical body is covered with a connecting portion between the first long body and the second long body, and the first annular recess is the first long An assembly process of covering with a scale and covering the second annular recess with the second elongated body and assembling as a ceramic tube calcined body;
And a main firing step of firing the ceramic tube calcined body having undergone the assembly step at a temperature higher than the calcining temperature. It is formed in a tubular shape made of ceramics, and has a first annular convex portion formed annularly along the circumferential direction on the outer periphery of one end portion, and annularly formed along the circumferential direction on the outer periphery of the other end portion. a cylindrical body having a second annular projection formed, made of ceramic, a first long body tubular is larger inner diameter than the outer diameter formed in the tubular body, made of ceramic, said first A forming step of forming a tubular second elongated body having the same inner diameter as the one elongated body;
A first firing step of firing the cylindrical body obtained by the molding step at a predetermined temperature;
A calcining step of calcining the first elongated body and the second elongated body obtained by the molding step;
The cylindrical body sintered in the first firing step is inserted into the calcined body of the first long body and the second long body obtained in the calcining step, and the first long body And the calcined body of the second long body, the cylindrical body is covered with a connecting portion between the first long body and the second long body, and the first annular convex portion is the first An assembly step of covering with a long body and covering the second annular convex portion with the second long body and assembling as a ceramic tube calcined body;
And a main firing step of firing the ceramic tube calcined body having undergone the assembly step at a temperature higher than the calcining temperature. It is formed in a tubular shape made of ceramics and has a first annular recess formed in an annular shape along the circumferential direction on the outer periphery of one end thereof, and formed in an annular shape along the circumferential direction on the outer periphery of the other end. a cylindrical body having a second annular recess which is made of ceramic, a first long body tubular inner diameter larger than the outer diameter of the tubular body is formed, made of ceramic, said first long A molding step for forming a tubular second elongated body having the same inner diameter as the scale body;
The cylindrical body obtained by the molding step is calcined at a predetermined temperature, and the first long body and the second long body are calcined at a temperature lower than the calcining temperature of the cylindrical body. A calcining process to
The cylindrical body obtained by the calcining step is inserted into the calcined body of the first long body and the second long body, and the calcined body of the first long body and the second long body is obtained. Connected, the cylindrical body is covered with a connecting portion between the first elongated body and the second elongated body, the first annular recess is covered with the first elongated body, and a second annular recess is formed. An assembly process of covering the second elongated body and assembling as a ceramic tube calcined body,
And a main firing step of firing the ceramic tube calcined body having undergone the assembly step at a temperature higher than the calcining temperature. It is formed in a tubular shape made of ceramics, and has a first annular convex portion formed annularly along the circumferential direction on the outer periphery of one end portion, and annularly formed along the circumferential direction on the outer periphery of the other end portion. a cylindrical body having a second annular projection formed, made of ceramic, a first long body tubular is larger inner diameter than the outer diameter formed in the tubular body, made of ceramic, said first A forming step of forming a tubular second elongated body having the same inner diameter as the one elongated body;
The cylindrical body obtained by the molding step is calcined at a predetermined temperature, and the first long body and the second long body are calcined at a temperature lower than the calcining temperature of the cylindrical body. A calcining process to
The cylindrical body obtained by the calcining step is inserted into the calcined body of the first long body and the second long body, and the calcined body of the first long body and the second long body is obtained. Connected, the cylindrical body is covered with the connecting portion of the first elongated body and the second elongated body, the first annular convex portion is covered with the first elongated body, and the second annular body An assembly process of covering the convex portion with the second long body and assembling as a ceramic tube calcined body,
And a main firing step of firing the ceramic tube calcined body having undergone the assembly step at a temperature higher than the calcining temperature. In the assembly process of the calcined body,
An average particle diameter of 100 nm or less is formed between the cylindrical body, the first long body, and the second long body, and has the same composition as the cylindrical body, the first long body, and the second long body. The method for producing a ceramic tube according to any one of claims 7 to 10, wherein a slurry containing 10% or more of said powder is used as an adhesive.