JP4757002B2 - Papermaking compacts used in connecting structures for fluid transport pipes - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a connecting structure for fluid transport pipes, and more particularly to a fluid transport pipe connecting structure suitable for connecting molten metal transport pipes.

  The applicant has proposed a technique described in Patent Document 1 below regarding a tubular casting manufacturing part used as a runner pipe or the like when manufacturing a casting. The technology described in Patent Document 1 is a paper tube base paper containing organic fibers, inorganic fibers and a binder, which is formed into a tubular shape. It is lighter and easier to handle than conventional refractory materials. Excellent for later disposal.

JP 2004-174605 A

  By the way, if it is going to connect the said casting manufacturing components which shape | molded the paper tube base paper in the shape of a tube, since the paper tube base paper is wound spirally, the part which is easy to come loose will be formed in the edge part. When casting parts are connected by fitting to form a mold and molten metal is injected from the injection port, the exposed end portion is exposed to the molten metal injection flow, and the end portion is There was a risk that the quality of the cast product could be affected.

  The objective of this invention is providing the connection structure of the pipe body for fluid transport which does not have a bad influence on the transport of a fluid, and the papermaking body used for it.

  According to the present invention, a first tube body having a wound layer in which a papermaking sheet is spirally wound and formed into a tubular shape, and a second tube body formed integrally with each other are disposed between end portions thereof. A connection structure for tubular bodies connected by fitting, wherein the first tubular body is fitted so as to cover the outer peripheral surface of the end portion of the second tubular body. The object is achieved by providing.

  Further, the present invention is a papermaking body constituting the second tubular body in the fluid transport tubular body connection structure of the present invention, wherein a convex portion worn by fitting on the outer peripheral surface thereof, and the first The papermaking molded object provided with the latching | locking part which contact | abuts the end surface when this pipe body is fitted is provided.

  According to the connecting structure for fluid transport pipes of the present invention and the papermaking compact used therefor, the pipes can be connected without fear of adversely affecting the transport of the fluid that is the transported material. Here, the fluid does not indicate only gas and liquid, but a mixed phase state, for example, a state where gas and solid (powder, granular material, etc.), liquid and solid, liquid and gas (liquid containing bubbles, etc.) are mixed. Also refers to. Moreover, as long as a gas such as air is present in the tubular body, the transportation of only the solid is a mixed phase state of the gas and the solid.

Hereinafter, the present invention will be described based on preferred embodiments thereof.
FIG. 1 shows an embodiment in which the connection structure of a fluid transport pipe body according to the present invention and the papermaking molded body used therefor are applied to connection of a transport pipe body (runner pipe) for molten metal in casting production. .

  As shown in FIG. 1, the connection structure 10 of the present embodiment includes runner pipes (first tube bodies) 11 and 11 each having a wound layer in which a papermaking sheet is spirally wound and formed into a tubular shape. And the integrally formed relay pipe (second pipe body) 12 are connected by fitting the end portions thereof, and the runner pipes 11, 11 are connected to the end portions of the second relay pipe 12. Are fitted so as to cover the outer peripheral surface.

  The runner pipe 11 has a water-repellent paper tube layer 111 as an outermost layer, and two paper tube layers (wound layers) in which a heat-resistant paper tube base paper is wound inside the water-repellent paper tube layer 111. ) It has a heat-resistant paper tube layer 112 made of 112A and 112B.

  The water-repellent paper tube layer 111 is composed of plain paper mainly composed of organic fibers and functional paper mainly composed of inorganic fibers. Here, “mainly composed of organic fibers or inorganic fibers” means that 50% or more of organic fibers or inorganic fibers are contained with respect to the total solid content.

  In addition to organic fibers or inorganic fibers, the water-repellent paper tube layer 111 includes a coating agent for developing water repellency described later, a sizing agent that imparts water repellency to the base paper itself, PVA (polyvinyl alcohol), polyethylene, and polypropylene. 1 type, or 2 or more types of chemical fibers, such as PET (polyethylene terephthalate), powder binder, etc. are included.

  Preferable organic fibers constituting the water-repellent paper tube layer 111 include pulp fibers, synthetic fibers (for example, nylon and polyester fibers), recycled fibers (for example, rayon and fibers), and the like. The organic fibers can be used alone or in combination of two or more.

  The preferred inorganic fibers constituting the water-repellent paper tube layer 111 include carbon fibers, glass fibers, mineral fibers such as rock wool, metal fibers such as gold threads, silver threads, copper threads, steel fibers, and mineral fibers such as slug fibers. Is mentioned. The inorganic fibers can be used alone or in combination of two or more.

  The water repellent paper tube layer 111 has water repellency. This water repellency is expressed based on the water repellent (coating agent, sizing agent, etc.). The water repellency is preferably 50% or less, more preferably 10%, in consideration of prevention of strength reduction of the casting part, water absorption rate (water absorption mass / mass before water absorption of the casting part). Here, the water absorption rate of the water-repellent paper tube layer 111 is measured by, for example, “paper and paperboard water absorption test method (Cobb method)” shown in JIS P 8140. However, the above water absorption is a value when the contact time between the test piece and water is 60 seconds.

The thickness of the water-repellent paper tube layer 111 is suitably 0.01 to 2.0 mm, but considering the moldability and strength when forming a wound tube, 0.03 to 1.5 mm is preferable. -1.0 mm is more preferable. Also, when functional paper is made of glass fiber, carbon fiber, etc. that are spread thinly and hardened with a binder, the rigid fibers such as carbon fiber from the inner layer directly stimulate the human skin through the holes (gap between the fibers). There is. In order to prevent this irritation, there is no hole penetrating from the front surface to the back surface of the functional paper, or even if there is a hole, the hole is not straight, or the maximum hole diameter is 7 μm or less so that the fiber does not come out. Preferably there is. This is because the average diameter of the carbon fibers is 7 μm. In addition, the plain paper mainly composed of organic fibers also has no holes penetrating from the front to the back of the plain paper in order to prevent irritation in the same manner as described above, or even if there is a hole, the hole is not straight. Alternatively, the maximum pore diameter is preferably 7 μm or less so that the fibers do not come out. In particular, the above-described method is more preferable for plain paper having many gaps between fibers such as Japanese paper.
Here, the plain paper is defined as follows in accordance with the definition of paper and paperboard stipulated by JIS. Plain paper is "paper made by attaching organic fibers, vegetable fibers, and other fibers, or paper made from wood pulp, waste paper, etc.".
On the other hand, functional paper is paper made by blending glass fibers, synthetic polymer substances, inorganic materials, etc., and is paper that has properties (heat resistance, high rigidity, etc.) that plain paper does not have. That is.
In addition, since water resistance can be expressed even in plain paper if the above-mentioned water repellent is added to the papermaking raw material, paper having water repellency is not limited to functional paper.

  Specific examples of the water-repellent paper tube layer 111 include raw materials such as corrugated cardboard, yellow paper, white paperboard, and other chemical fibers, such as wood pulp, chemical pulp, groundwood pulp, straw pulp, and waste paper. Chemical fiber paper, general fine paper, printing paper, kraft paper, and the like are conceivable, but considering the price of the base paper and availability, kraft paper is mentioned. Here, craft paper refers to paper made from kraft pulp including JIS P 3401 kraft paper and JIS P 3412 kraft stretched paper. The outermost layer is preferably plain paper because of its price and availability, but any paper having water repellency may be used. For example, it may be a functional paper produced by making glass wool, carbon fiber or the like dispersed in water into paper, and directly spraying a binder on the dehydrated one.

  The thickness of the heat-resistant paper tube layer 112 is preferably 0.3 mm or more, particularly 0.5 mm or more in consideration of the strength as a runner tube and the endurance of the dynamic pressure when molten metal flows.

  The paper tube layers 112A and 112B constituting the heat resistant paper tube layer 112 contain inorganic powder, inorganic fiber, organic fiber, thermosetting resin, papermaking binder and water repellent.

  The paper tube layers 112A and 112B constituting the heat resistant paper tube layer 112 are based on the total mass of the inorganic powder, the inorganic fiber, the organic fiber, the thermosetting resin, the papermaking binder, and the water repellent. The blending ratio (mass ratio) of each component is inorganic powder / inorganic fiber / organic fiber / thermosetting resin (solid content) / papermaking binder (solid content) / water repellent = 0-70% / 1 The range of 60% / 1-40% / 1-40% / 1-10% / 0-5% (mass ratio) is preferable, 40-70% / 1-10% / 1-25% / 1-25% / 1-10% / 0-5% (mass ratio) is more preferable, 50-70% / 1-8% / 1-20% / 10-25% / 3-7% / 0-1% (mass ratio) Is more preferable. Moreover, the content mass ratio of each said component is 100% in total. When the blending of the inorganic powder is within such a range, the shape retention at the time of casting and the surface property of the molded product are good, and the mold release property after molding is also suitable. When the blending ratio of the inorganic fibers is within such a range, papermaking properties and shape retention during casting are good. When the blending ratio of the organic fibers is within such a range, papermaking properties are good, and the amount of combustion gas generated during casting can be reduced, so that blow back (back flow of molten iron) can be suppressed. When the mixing ratio of the thermosetting resin is within such a range, moldability, shape retention after casting, and surface smoothness are good. When the papermaking binder is within such a range, the powder component in the raw material can adhere to the fibers, and the fibers can be appropriately entangled to form an optimum floc for papermaking, and the yield is also good. When the mixing ratio of the water repellent is within such a range, it is possible to prevent the adhesive used when manufacturing a casting manufacturing part from the base paper made by papermaking from entering the base paper, and an appropriate amount of adhesive. Is enough. Further, it is possible to prevent moisture in the foundry sand from penetrating into the foundry manufacturing part when the foundry producing part is buried in the foundry sand. In addition, the usage environment of the heat-resistant paper tube layer is in a dry state, or the thermosetting resin may exhibit water repellency depending on the type and amount of the thermosetting resin. It is not necessary to add a water repellent.

  Examples of the inorganic powder include obsidian, mullite, and graphite such as plate-like graphite. These inorganic powders can be used alone or in combination of two or more. When the carbon content of the casting is 4.2% or less, a carburization phenomenon (a phenomenon in which carbon is absorbed into the casting and becomes brittle) occurs. In this case, it is necessary to use an inorganic powder containing silica to prevent the carburization phenomenon from the cast carbide. Obsidian, mullite, etc. are preferably used as the inorganic powder. Further, when the carbon content of the casting is 4.2% or more, the inorganic powder may not be included.

  The inorganic fiber mainly forms a skeleton of the heat-resistant paper tube layer, and maintains its shape without being burned by the heat of molten metal at the time of casting, for example. Examples of the inorganic fiber include carbon fiber, artificial mineral fiber such as rock wool, ceramic fiber, and natural mineral fiber, and these can be used alone or in combination of two or more. Among these, it is preferable to use pitch-based or polyacrylonitrile (PAN) -based carbon fibers having high strength even at high temperatures from the viewpoint of effectively suppressing shrinkage due to carbonization of the thermosetting resin, and in particular, PAN-based carbon. Fiber is preferred.

  The inorganic fibers have an average fiber length of 0.1 to 10 mm, particularly 0. 10 mm, from the viewpoints of ease of forming when the heat-resistant paper tube paper is made and formed, and quality such as uniform thickness of the molded product. What is 5-8 mm is preferable. When the average fiber length is more than 0.1 mm, the probability that the fibers pass through the eyes of the papermaking net is low, so that it is possible to suppress the mixing of the fibers with the white water and the yield. Further, the strength of the obtained molded product is increased. On the other hand, when the average fiber length is less than 10 mm, the entire molded product is not bulky and the surface of the molded product is hardly uneven, and good fluidity of the molten metal is maintained during casting.

  Examples of the organic fiber include pulp fiber, synthetic fiber, and recycled fiber (for example, rayon fiber). The organic fibers can be used alone or in combination of two or more. Pulp fibers are preferred from the viewpoints of moldability, strength after drying, and cost.

  Examples of the pulp fiber include wood pulp, cotton pulp, linter pulp, bamboo straw and other non-wood pulp. Pulp fibers can be used singly or in combination of two or more of these virgin pulp or waste paper pulp. The pulp fiber is particularly preferably waste paper pulp from the viewpoint of easy availability, environmental protection, and reduction of production costs.

  In view of surface smoothness and impact resistance, the organic fiber preferably has an average fiber length of 0.1 to 20 mm, particularly 0.5 to 10 mm.

  The thermosetting resin is a component necessary for maintaining the normal temperature strength and hot strength of the heat-resistant paper tube layer 112, improving the surface property of the heat-resistant paper tube layer, and improving the surface roughness of the casting. It is. Examples of the thermosetting resin include a phenol resin, an epoxy resin, and a furan resin. Among these, in particular, there is little generation of combustion gas, there is a combustion suppressing effect, the residual carbon ratio after pyrolysis (carbonization) is as high as 25% or more, and it is good to form a carbonized film when used for casting. It is preferable to use a phenol resin from the viewpoint that a cast surface can be obtained. Here, the residual carbon ratio refers to a value obtained by dividing the mass measured after heating a sample of the thermosetting resin from room temperature to 1200 ° C. at a heating rate of 50 ° C./min in a nitrogen atmosphere by the mass before heating. . Since the combustion gas is released from the thermosetting resin during heating, the mass after heating becomes lighter than before heating. As the phenol resin, a novolak phenol resin that requires a curing agent or a resol type phenol resin that does not require a curing agent is used. In order to suppress the eluted free phenol in white water as much as possible, it is preferable to use a low free phenol resin. For example, a high molecular weight type of resol phenol resin synthesized with a basic catalyst or an acidic catalyst is preferable. When a novolac phenol resin is used, a curing agent is required. Since the curing agent is easily soluble in water, it is preferably applied to the surface of the base paper after dehydration. It is preferable to use hexamethylenetetramine or the like as the curing agent. The thermosetting resins can be used alone or in combination of two or more.

  In addition to carbon monoxide and carbon dioxide, the combustion gas includes hydrocarbons such as methane and ethylene.

  Examples of the papermaking binder include starch, gelatin, guar gum, natural polymers such as CMC (carboxymethylcellulose), sponge (polyamideamine epichlorohydrin resin), PVA (polyvinyl alcohol), PAM (polyacrylamide), PEO (polyethylene oxide), and the like. And water-soluble synthetic polymers and latexes such as styrene / butadiene, acrylonitrile / butadiene, acrylic and vinyl acetate, and inorganic binders such as colloidal silica and alumina. Among these, it is preferable to use sponge, CMC, acrylic latex, etc., which have excellent powder fixing performance. The addition amount of the papermaking binder is preferably 0.01 to 5%, particularly 0.02 to 1% of the organic fiber mass in terms of solid content. These papermaking binders can be used alone or in combination of two or more.

  Examples of the sizing agent that exhibits water repellency include natural systems such as rosin, synthetic systems such as AKD (alkyl ketene dimer) and ASA (alkenyl succinic anhydride), and waxes. Among these, AKD which has excellent water repellency in a small amount in a neutral region and excellent in acid resistance and alkali resistance compared to rosin or the like is preferable.

  In addition to the above components, other components such as a flocculant and a colorant can be added to the paper tube layers 112A and 112B constituting the heat resistant paper tube layer 112 in an appropriate ratio.

  The total thickness of the runner pipe 11 can be appropriately set according to the place where it is used, but 0.5% is taken into consideration when securing the strength as a runner pipe, ensuring air permeability, suppressing manufacturing costs, and the like. -6.0 mm is preferable and 1.0-3.0 mm is more preferable.

  The runner pipe 11 is preferably 20N or more, more preferably 40N or more, in terms of securing strength, the compressive strength before being used for casting. Here, the compressive strength of the runner tube 11 is measured by compressing the tubular molded product to a length of 60 mm and using a Tensilon universal testing machine (RTA500 manufactured by A & D Co., Ltd.) with the cut surface lying sideways. The compressive strength of the side surface of the tube measured by pushing down at a compression speed of 10 mm / min with a vessel.

  The runner pipe 11 has a moisture content (mass moisture content) in a state before being used for casting of 20% or less, and more preferably 10% or less from the viewpoint of suppressing generation of water vapor as much as possible when contacting the molten metal. This is because the generation of water vapor causes blowback (back flow) from the molten metal inlet.

As will be described later, the relay pipe 12 is integrally formed by a wet papermaking method, and the runner pipes 11 and the ridge parts (convex parts) 121 and 122 worn by fitting are fitted to the outer peripheral surface part thereof. A locking portion 123 is sometimes provided that contacts the end surface. The protrusions 121 (first protrusions) extend along the direction of insertion into the runner pipe 11 and are provided at predetermined intervals on the outer peripheral surface. The protrusion 122 (second protrusion) is provided on the outer peripheral surface of the relay pipe 12 so as to connect the protrusions 121. The number of protrusions 121, 122, the arrangement interval, and the like are set according to the form (length, inner diameter, material, etc.) of the relay pipe 12.

  The fitting allowance length L12, the inner diameter φ12, and the thickness T12 of the relay pipe 12 are appropriately set according to the application. When used for connecting runner pipes as in this embodiment, the longer the fitting allowance length L12, the more stable the connection structure can be obtained. Is preferable. The inner diameter φ12 is preferably 15 to 150 mm, and the thickness T12 is preferably 0.2 to 5.0 mm.

  The protrusion 121 is provided over the entire length of the relay pipe 12. Thus, by providing the protrusion 121 over the entire length of the relay pipe 12, the cut relay pipe 12 always has the protrusion 121 regardless of the position at which the relay pipe 12 is cut. Become. The protrusion 121 is worn when the runner pipe 11 is connected to the relay pipe 12 by fitting, and the contact force therebetween becomes stronger and functions to obtain a strong fitting state, and in the longitudinal direction. It also has a function to supplement the strength of the papermaking compact. The height H121 and the width W121 of the ridge 121 are appropriately set according to the size, mass, etc. of the relay pipe 12, but the height H121 is 0.3 to 3 mm and the width W121 is 0.2 mm or more. It is preferable. In order to obtain a stronger fitting state, it is preferable that the protrusions 121 are provided at equal intervals. Further, the inner diameter of the runner pipe 11 that crushes the protrusion 121 by fitting is slightly smaller than the outer diameter of the relay pipe 12 obtained by a line connecting the vertices of the protrusions of the relay pipe 12 having the protrusion. Set smaller.

The height H122 of the ridge 122 is set to be lower than the height H121 of the ridge 121. The protrusion 122 is provided at a predetermined interval from both ends, and is preferably provided at a basic length unit, for example, every 1 cm, 5 cm, or 10 cm. By providing the protrusions 122 every basic length unit in this way, in addition to reinforcing the relay pipe 12, when the relay pipe 12 is cut into a predetermined length, the fitting length (the length of the fitting portion) ) Can be used as an indicator when confirming.

The height H123 of the locking portion 123 only needs to be a height that can abut against the tip of the runner 11 and restrict insertion.

  The relay pipe 12 is preferably 20N or more, more preferably 40N or more in compressive strength before being used for casting in terms of securing strength. Here, the compressive strength of the relay pipe 12 refers to the compressive strength of the pipe side surface measured in the same manner as the runner pipe.

  The relay pipe 12 can be made of the same material as the paper tube layers 112A and 112B constituting the heat-resistant paper tube layer 112 described above. If it is such a material, the relay pipe 12 may be made of the same material as the paper tube layers 112A and 112B, or may be made of a different material. Is preferred.

Next, the manufacturing method of the runner pipe 11 used for the said connection structure 10 is demonstrated.
First, a plain paper and a heat-resistant paper tube base paper to be used as the base paper for the water-repellent paper tube layer 111 and the heat-resistant paper tube layer 112 are prepared.
These base papers are respectively prepared raw slurry in which each component constituting the water-repellent paper tube layer and the heat-resistant paper tube layer is dispersed in a dispersion medium, paper is made from these raw material slurry by a wet paper making method, dehydrated, Prepare by drying.

  Examples of the dispersion medium include water, white water, and solvents such as ethanol and methanol. Among these, water is preferable from the viewpoints of papermaking, dewatering molding stability, quality stability, cost reduction, and ease of handling.

  Additives such as flocculants and preservatives can be added to the raw material slurry.

The raw paper slurry prepared as described above is used to make a base paper for each paper tube layer.
Examples of paper making methods of these base papers include, for example, a paper making method using a continuous paper making machine such as a circular paper machine, a long paper machine, a short paper machine, a twin wire paper machine, and a batch paper making method. A papermaking method such as a koji method can be employed.

  Next, each dehydrated base paper is dried in a drying step. For drying in the drying step, a conventional method conventionally used for paper drying is used. In order to strengthen the hydrogen bond between fibers and improve the mechanical strength of each base paper, it is preferable to dry each base paper until the water content becomes 30% or less, preferably 10% or less. .

  Next, the obtained base paper is cut into a predetermined width and subjected to winding tube processing. A conventionally used technique is used for the winding tube processing. First, heat-resistant paper tube base paper is spirally wound around the outer periphery of the winding tube processing shaft and formed into a cylindrical shape, and then heat-resistant paper tube base paper is spirally wound on the outside and heat-resistant. The paper tube layer. Then, the plain paper to be the outermost water-repellent paper tube layer is overlaid on the outer side. The base paper constituting the adjacent layers may be wound in the same direction or in different directions. In the case of the same direction, it is preferable that the wrapping is performed so as to cover the seam portion of the base paper that has been previously lap-wrapped. The width of each base paper, the stacking width, the inner diameter of the paper tube, and the like are set according to the mass of the casting (amount of molten metal passing through the tube) and the molding strength (strength that can withstand the pressure when making the sand mold). The layers are bonded by applying an adhesive.

  After the lap winding of all the layers is completed, it is dried by heating at a predetermined temperature and cut into a predetermined dimension to complete the manufacture of the runner pipe.

Next, a method for manufacturing the relay pipe 12 used in the connection structure 10 will be described.
For example, as described below, the relay pipe 12 is manufactured by making a wet fiber laminate by a wet papermaking method using a papermaking mold, and then dehydrating and drying the fiber laminate. In addition, although the protrusion parts 121 and 122 and the latching | locking part 123 can be formed also at the time of papermaking, the method formed at the time of drying is shown here.

  For making the forming intermediate body of the relay pipe 12, a cavity substantially corresponding to the outer shape of the relay pipe 12 is provided, and the formation surface of the cavity is covered with a paper making net having a predetermined opening and a wire diameter. A papermaking mold is used which has a fluid flow passage which is open at the forming surface and communicates with the outside. It is preferable to use the papermaking mold in which the cavity is formed by combining two or more split molds.

  Then, a raw material slurry using the same material as that for the heat-resistant paper tube layer is supplied into the cavity of the papermaking mold, the raw material slurry is sucked through the flow passage, and the solid in the raw material slurry is placed on the papermaking net. Deposit minutes.

  After a predetermined fiber laminate (no protruding portion is formed) is deposited on the papermaking net, the fiber laminate deposited on the papermaking net is dehydrated.

  The dehydration of the fiber laminate is preferably performed by sucking and removing moisture from the fiber laminate through the flow passage. When the fiber laminate is dehydrated to a predetermined moisture content, the fiber laminate is taken out from the papermaking mold and transferred to a dry molding step. The dehydration can also be performed while inserting a core similar to that used in the drying step described later into the fiber laminate, expanding the core and pressing the fiber laminate from the inside.

  The moisture content (% by mass) of the fiber laminate when dehydration is completed is preferably 30 to 80% from the viewpoint of preventing damage to the fiber molded body at the time of shifting to the dry molding step, improving drying efficiency, and the like. 70% is more preferable. Even when the dehydration is finished, no protrusion is formed yet.

Next, the fiber laminate is dry-molded as follows using a dry mold and a core.
The drying mold has a cavity that substantially matches the outer shape of the relay pipe 12, and is provided with slits and recesses corresponding to the shape of the desired protrusions to be formed. As the dry mold, it is preferable to use the dry mold in which the cavity is formed by combining two or more split molds. The core is preferably made of a heat-resistant elastic material such as silicone rubber.

  In the drying step, first, the fiber laminate that has been dehydrated and molded is placed in a drying mold, and then the drying mold is heated to a predetermined temperature by the heating means, and the core is inserted into the cavity. The fluid is supplied to the core to expand the core, and the fiber laminate is pressed against the inner surface of the drying mold (the surface on which the cavity of each split mold is formed) and dried while pressing the fiber laminate from the inside. Thus, by pressing the fiber laminate from the inside with the core, a part of the surface of the fiber laminate enters the slit and the recess, and the protrusion corresponding to the slit and the recess is the relay pipe. 12 surfaces are formed. Moreover, the inner surface of the obtained relay pipe 12 can also be made smooth.

  The temperature of the drying mold is preferably from 100 to 250 ° C., more preferably from 120 to 220 ° C. from the viewpoint of preventing the fiber laminate from being burnt and drying efficiency. In addition, before a fiber laminated body is arrange | positioned in a dry mold, it is preferable that a dry mold is heated and hold | maintained at predetermined temperature.

  The pressure of the fluid when supplying the fluid into the core can be appropriately set according to the fiber laminate to be dried, but is preferably 0.01 to 5 MPa, particularly preferably 0.1 to 3 MPa. Examples of the fluid used for expanding the core include air, hot air (heated pressurized air), gas such as steam and superheated steam, oil (heating oil), and other liquids. In particular, it is preferable to use pressurized air, hot air, and superheated steam from the viewpoint of operability.

  When the fiber laminate is dried to a predetermined moisture content, the suction through the flow passage is stopped, the fluid in the core is discharged to contract the core, and the core is taken out from the dry mold.

  Then, the drying mold is opened, the relay pipe is taken out, and the production is finished. The relay pipe can be subjected to various processes such as trimming, printing, coating, and inner / outer surface finishing as required. Here, the coating treatment refers to, for example, a coating treatment with colloidal silica or the like for improving the hot strength (the mechanical strength when the tube is in contact with the molten metal).

Since the relay pipe 12 obtained in this way has the protrusion 121 on the outer peripheral surface portion, when the relay pipe 12 and the runner pipe 11 are fitted and connected, the protrusion 121 is provided. By crushing and fitting them, a strong connected state can be obtained. Moreover, since the relay pipe 12 has the protrusion 122, its strength is reinforced, and the protrusion 122 can be used as an index when cutting the paper-molded molded body 1 to a desired length. It also serves as an index for confirming the fitting length (length of the fitting portion). Moreover, since it has the latching | locking part 123, it can confirm that it is fitting reliably.

As described above, according to the connection structure 10 of the fluid transport pipe body of the present embodiment, the end portion of the runner tube 11 that is easily loosened is not exposed to the molten metal at the fitting portion, and therefore the end portion is not flowed. There is no risk of affecting the quality of the cast product. Further, since the protrusions 121 and 122 are provided on the outer peripheral portion of the relay pipe 12, it is easy to handle when cutting or assembling a mold.

  In addition, since the relay pipe 12 can be easily cut with a light and simple device as in the prior art, it is excellent in handling in this respect as well.

  4 to 11 show another embodiment of the relay pipe (papermaking body) used in the fluid transport pipe connecting structure of the present invention. In these embodiments, portions common to the relay pipe 12 of the above embodiment are denoted by the same reference numerals. In addition, the back view of each embodiment is abbreviate | omitted since it is bilaterally symmetrical with the front view.

The papermaking body of the present invention is formed into an L-shaped bent shape like the relay pipe 12 ′ of the embodiment shown in FIGS. 4 and 5 and FIGS. 8 and 9, and wound around the ends thereof. It can also be set as the form which connects the pipe body which has a layer by fitting.
Moreover, like the relay pipe 12 ′ of the embodiment shown in FIGS. 6 and 7 and FIGS. 10 and 11, it is formed into a bifurcated form, and a tubular body having a winding layer is fitted to each end. It can also be set as the form connected by.

  The present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

  In the embodiment, the heat-resistant paper tube layer 112 is composed of two paper tube layers and the water-repellent paper tube layer is composed of one paper tube layer. However, the heat-resistant paper tube layer is composed of one or three or more paper tubes. It is also possible to form a layer, and the water-repellent paper tube layer can be composed of two or more paper tube layers. Each paper tube layer is multi-layered from the viewpoints of withstanding the dynamic pressure during casting of molten metal, preventing leakage of molten metal from the winding part, and withstanding the pressure when the tubular casting production parts are buried in sand. It is preferable to make it. However, these layer configurations take into consideration the dynamic pressure of the molten metal at the time of casting, the pressure when the tubular casting production part is buried in sand, the production cost of the tubular casting production part, the amount of combustion gas generated, etc. Thus, the paper tube layers can be appropriately set as needed, and the paper tube layers are not limited to being formed of multiple layers, and each paper tube layer may be a single layer.

  The present invention is suitable for connecting the runner pipes used in the mold as described above, but can also be applied to the connection of other pipe bodies constituting the mold.

  The present invention can be applied to connection of tubular bodies constituting a mold.

It is a half sectional view showing typically one embodiment of the connection structure of the pipe for fluid transportation of the present invention. It is a perspective view which shows typically the pipe body which has a winding layer used for one Embodiment of the connection structure of the pipe structure for fluid transportation of this invention. It is a figure which shows typically the relay pipe used for one Embodiment of the connection structure of the pipe for fluid transportation of this invention, (a) is a top view, (b) is a front view, (c) is a principal part. It is an enlarged view. It is a figure which shows the relay pipe in other embodiment of the connection structure of the fluid transport pipe body of this invention, (a) is a top view, (b) is a left view, (c) is a front view, (d) Is a right side view, and (e) is a bottom view. It is AA sectional drawing of the relay pipe shown in FIG. It is a figure which shows the relay pipe in other embodiment of the connection structure of the fluid transport pipe body of this invention, (a) is a top view, (b) is a left view, (c) is a front view, (d) Is a right side view, and (e) is a bottom view. It is BB sectional drawing of the relay pipe shown in FIG. It is a figure which shows the relay pipe in other embodiment of the connection structure of the fluid transport pipe body of this invention, (a) is a top view, (b) is a left view, (c) is a front view, (d) Is a right side view, and (e) is a bottom view. It is CC sectional drawing of the relay pipe shown in FIG. It is a figure which shows the relay pipe in other embodiment of the connection structure of the fluid transport pipe body of this invention, (a) is a top view, (b) is a left view, (c) is a front view, (d) Is a right side view, and (e) is a bottom view. It is DD sectional drawing of the relay pipe shown in FIG.

Explanation of symbols

10 Connection structure of fluid transport pipe 11 Runner pipe (first pipe)
12 Relay pipe (second pipe)

Claims (2)

First structure having a wound layer in which a sheet-forming sheet is spirally wound and formed into a tubular shape in a connection structure of fluid-transporting pipe bodies used for connection of a molten-metal transportation tube body, and wet papermaking And a second tubular body, which is a paper-molded molded body integrally formed by the method, is connected by fitting of the end portions thereof, and the first tubular body has an outer peripheral surface of the end portion of the second tubular body. A papermaking molded body constituting the second pipe body in the connecting structure of fluid transport pipe bodies fitted so as to cover ,
A convex portion that is worn by fitting to the outer peripheral surface and an engaging portion that abuts on the end surface when the first tubular body is fitted are provided integrally with the outer peripheral surface, respectively. The papermaking molded product. As the convex portions, a first convex portion extending along the insertion direction into the first tubular body , and a closed annular second convex portion extending in a direction intersecting the insertion direction are provided. has a convex portion of said second, papermaking molded article according to claim 1, provided with a plurality at predetermined intervals in the longitudinal direction of the second pipe.

Images