JP5578709B2 - Mold production equipment - Google Patents

Description

  The present invention relates to an apparatus for producing a mold used for casting.

  Currently used molds are generally hard molds such as ordinary sand molds, high pressure molds, high speed molds and other clay molds as binders, thermosetting molds, self-hardening molds, gas curing molds, precision casting molds, etc. They are classified into special molds that use adhesive binders and other molds. These molds have merits and demerits, but they often have a problem that it takes time to solidify or cure the binder and it is difficult to stably produce the mold in a short time.

  Therefore, the present applicant fills a mold with a coated sand prepared by mixing a binder with a refractory aggregate, blows steam into the mold, and heats the binder with steam to solidify. It proposes a method for producing a mold by curing.

  FIG. 5 shows an example of an apparatus for producing a mold using water vapor (see Patent Documents 1 and 2, etc.). As shown in FIG. 5A, an injection port 11 is provided on the upper surface of a mold 1 formed by providing a cavity 10 therein, and an exhaust port 13 closed by a net 12 is provided on the lower surface of the mold 1. It is. The coated sand 2 is stored in a storage tank 14, and an air supply pipe 16 with a cock 15 is connected to the storage tank 14. Then, after the nozzle port 17 at the lower end of the storage tank 14 is matched with the injection port 11 of the mold 1, the inside of the storage tank 14 is pressurized by opening the cock 15 and blowing air into the storage tank 14. The coated sand 2 is blown into the molding die 1 with this air pressure as shown in FIG. 5B, and the coated sand 2 is filled into the cavity 10 of the molding die 1. Since the exhaust port 13 is blocked by the net 12, the coated sand 2 does not leak from the exhaust port 13.

  After filling the coated sand 2 into the mold 1 in this way, the storage tank 14 is removed from the inlet 11 of the mold 1, and then the water vapor pipe 19 is connected to the inlet 11 as shown in FIG. . The steam pipe 19 is connected to a steam generator 3 formed with a boiler or the like. Then, the cock 18 provided in the steam pipe 19 is opened, and the steam sent from the steam generator 3 is blown into the cavity 10 of the mold 1 through the steam pipe 19. The water vapor passes between the particles of the coated sand 2 filled in the mold 1 to heat the coated sand 2 and is then discharged from the exhaust port 13. Since water vapor has high condensation latent heat, by blowing water vapor in this way, the latent heat is transmitted when the water vapor contacts the coated sand 2, and the entire coated sand 2 in the mold 1 can be instantaneously heated. The binder can be solidified or cured in a short time. Therefore, it is possible to stably mold a mold in a short time.

Japanese Patent No. 3563973 Japanese Patent No. 4181251 WO2007 / 132669

  When the steam is blown into the cavity 10 of the mold 1 as described above and the coated sand 2 filled in the cavity 10 is heated, the steam is blown as shown in FIG. In the initial stage of blowing water vapor into the mold 1, a part of the heat of the water vapor is taken away by the mold 1. For this reason, the heating efficiency of the coated sand 2 by water vapor | steam became low, and there existed a limit in shortening the molding time of a casting_mold | template.

  Further, water vapor is supplied to the cavity 10 of the mold 1 from the injection port 11, but it is difficult to uniformly distribute the water vapor blown into the cavity 10 from the injection port 11 to every corner of the cavity 10. . In particular, when the shape of the mold is complicated or elongated, it is difficult to uniformly heat the coated sand 2 by spreading water vapor to every corner of the cavity 10. For this reason, there has been a problem that it is difficult to uniformly produce a mold having a complicated shape and an elongated shape.

  The present invention has been made in view of the above points, and it is an object of the present invention to provide a mold manufacturing apparatus that can shorten the molding time of the mold and can manufacture the mold uniformly. is there.

The mold manufacturing apparatus according to the present invention heats a molding die 1 having a cavity 10 filled with a coated sand 2 coated with a refractory aggregate with a binder, and the coated sand 2 filled in the molding die 1. In a mold manufacturing apparatus provided with a steam generator 3 for generating steam, a mold heating cavity 5 provided in the mold 1 at a position surrounding the cavity 10, a steam generator 3, and a mold heating cavity 5, a plurality of steam supply passages 6 for constantly supplying the steam delivered from the steam generator 3 to the mold heating cavity 5, and a plurality of mold heating between the mold heating cavity 5 and the cavity 10, A steam introduction path 7 for introducing water vapor supplied to the mold heating cavity 5 into the cavity 10, and an inlet 22 and an outlet 23 are formed in the mold heating cavity 5. But with steam return passage 36 is connected to the outlet 23, in which the opening and closing valve 35 which coated sand 2 into the cavity 10 is closed after being filled, characterized in that provided in the steam return path 36 is there.

  According to the present invention, the mold heating cavity 5 is provided in the mold 1 at a position surrounding the cavity 10, and the steam fed from the steam generator 3 is supplied to the mold heating cavity 5 through the steam supply path 6. Therefore, the mold 1 can be preheated using steam, and when the steam is supplied to the cavity 10 and the coated sand 2 is heated, the heat of the steam is deprived by the mold 1. Therefore, the heating efficiency of the coated sand 2 by water vapor can be increased, and the molding time of the mold can be shortened. In addition, a plurality of steam introduction paths 7 are provided between the mold heating cavity 5 and the cavity 10 disposed at a position surrounding the cavity 10, and water vapor supplied to the mold heating cavity 5 is passed through the steam introduction path 7 to form the cavity. 10, the steam supplied to the mold heating cavity 5 is blown from a plurality of locations surrounding the cavity 10 through the steam introduction path 7, and the steam is uniformly distributed throughout the cavity 10. By supplying, the entire coated sand 2 in the cavity 10 can be heated uniformly, and a homogeneous mold can be manufactured.

  In the present invention, a water vapor main supply passage 4 is provided between the water vapor generator 3 and the cavity 10 of the mold 1 and supplies the water vapor sent from the water vapor generator 3 into the cavity 10. It is what.

  According to the present invention, a large amount of water vapor is supplied to the cavity 10 of the mold 1 through the water vapor main supply path 4 and the coated sand 2 in the cavity 10 is heated with this water vapor, as described above. Steam can be introduced into the cavity 10 from the path 5 through the steam introduction path 7, and the coated sand 2 can be heated uniformly, and a homogeneous mold can be produced in a short time.

  In the present invention, the steam generator 3 includes a superheater 8, and the steam is superheated steam generated by overheating in the superheater 8.

  Superheated steam is high-temperature dry steam, and by using such superheated steam as water vapor, the generation of condensed water from water vapor in the mold 1 is reduced, and the coated sand 2 in the mold 1 Heating efficiency can be increased.

  The present invention also includes a storage tank 14 that supplies the coated sand 2 to the cavity 10 of the mold 1 and stores a sand preheater 40 that preheats the coated sand 2 using steam generated by the steam generator 3 as a heat source. The tank 14 is provided.

  According to the present invention, the coated sand 2 can be preheated using water vapor. When the coated sand 2 is heated with the water vapor supplied into the cavity 10, the heat of the water vapor is applied at the initial stage of heating. 2 can be prevented from condensing and condensing, and the heating efficiency of the coated sand 2 by water vapor can be increased, and the molding time of the mold can be shortened.

  According to the present invention, the mold heating cavity 5 is provided in the mold 1 at a position surrounding the cavity 10, and the steam delivered from the steam generator 3 is supplied to the mold heating cavity 5 through the steam supply path 6. Therefore, the mold 1 can be preheated using steam, and when the steam is supplied to the cavity 10 and the coated sand 2 is heated, the heat of the steam is deprived by the mold 1. Therefore, the heating efficiency of the mold 1 with water vapor can be increased, and the molding time of the mold can be shortened. In addition, a plurality of steam introduction paths 7 are provided between the mold heating cavity 5 and the cavity 10 disposed at a position surrounding the cavity 10, and water vapor supplied to the mold heating cavity 5 is passed through the steam introduction path 7 to form the cavity. 10, the steam supplied to the mold heating cavity 5 is blown from a plurality of locations surrounding the cavity 10 through the steam introduction path 7, and the steam is uniformly distributed throughout the cavity 10. By supplying, the entire coated sand 2 in the cavity 10 can be heated uniformly, and a homogeneous mold can be manufactured.

It is a schematic sectional drawing which shows an example of embodiment of this invention. It shows another example of the embodiment of the present invention, (a) is a schematic cross-sectional view of the mold, (b) is a schematic side view of the mold. It is a schematic sectional drawing, such as a storage tank and a steam generator, showing an example of an embodiment of the invention. It is a schematic sectional drawing which shows an example of other embodiment of this invention. A prior art example is shown, and (a) to (c) are schematic views.

  Embodiments of the present invention will be described below.

  FIG. 1 shows an example of an embodiment of the present invention. The molding die 1 is formed by providing a cavity 10 therein, and in the embodiment shown in FIG. An injection port 11 is provided on the upper surface of the mold 1, and an exhaust port 13 is provided on the lower surface of the mold 1 so as to be closed by a net 12 such as a metal mesh and formed to be air permeable.

  The mold 1 is provided with a mold heating cavity 5. In the embodiment of FIG. 1, the mold heating cavity path 5 is provided by forming a hollow inside the wall surface of the mold 1. A pair of mold heating cavities 5 are provided so that the mold 1 can be divided into left and right halves, and the pair of mold heating cavities 5 are formed so as to surround the entire outer periphery of the cavity 10. The mold heating cavity 5 is opened on the outer surface of the mold 1 at one end as an inlet 22 and at the other end as an outlet 23.

  A steam introduction path 7 is provided between the mold heating cavity path 5 and the cavity 10. The steam introduction path 7 is provided between the inner peripheral surface of the mold heating cavity 5 and the outer peripheral surface of the cavity 10, and by drilling a hole penetrating the thickness of the wall surface of the mold 1, One end is formed in the mold heating cavity 5 and the other end is opened in the cavity 10. A large number of the steam introduction paths 7 are provided so as to be arranged over the entire outer peripheral surface of the cavity 10. The inner diameter of the steam introduction path 7 is preferably smaller than the diameter of the coated sand 2 so that the coated sand 2 does not enter. However, as will be described later, steam blows out from the steam introduction path 7 into the cavity 10. Therefore, even if the inner diameter of the steam introduction path 7 is slightly larger than the diameter of the coated sand 2, the coated sand 2 does not enter the steam introduction path 7 and clog the inside of the steam introduction path 7.

  As the mold heating cavity 5, in addition to forming the mold 1 with a hollow wall as shown in FIG. 1, as shown in FIG. It may be provided to form the mold heating cavity 5. The mold heating cavity 5 formed as a hollow channel is formed in a meandering shape as shown in FIG. 2B so that the entire outer periphery of the cavity 10 can be surrounded. . When the mold heating cavity 5 is formed as a meandering cavity channel, the steam introduction channel 7 can be provided along the longitudinal direction of the mold heating cavity 5. The mold heating cavity 5 is formed by embedding a hollow pipe or the like in the mold 1 in addition to forming the inside of the mold 1 as a hollow cavity as shown in FIGS. Also good.

  The steam generator 3 is formed with a boiler 25, and a water introduction path 27 provided with an on-off valve 26 is connected to the boiler 25. Water supplied from the water introduction path 27 can be heated in the boiler 25 to generate water vapor (saturated water vapor). In FIG. 1, 28 is a pressure gauge and 29 is a safety valve. When the steam generated in the boiler 25 is used as it is, it is sent out from the steam delivery path 30 connected to the boiler 25. Further, by connecting the superheater 8 to the water vapor delivery path 30, the water vapor generated by the boiler 25 can be further heated by the superheater 8 and sent out from the water vapor delivery path 30 as superheated steam. Superheated steam is water vapor in a complete gas state generated by further heating saturated steam and having a temperature equal to or higher than the boiling point, and is dry steam at 100 ° C. or higher. The superheated steam may be one that has been expanded at a constant pressure without increasing the pressure, or may be pressurized steam that has been increased in pressure without being expanded. Although the temperature of the superheated steam is not particularly limited, the temperature of the superheated steam can be increased to about 900 ° C., and therefore, the temperature may be set between 100 and 900 ° C. as necessary. In FIG. 1, 31 is an on-off valve provided on the entry side of the steam delivery path 30 to the superheater 8, and 32 is an on-off valve provided on the exit side of the steam delivery path 30 from the superheater 8.

  The main steam supply path 4 and the steam supply path 6 are branched and connected to the end of the steam delivery path 30 beyond the on-off valve 32. The steam main supply path 4 and the steam supply path 6 are provided with on-off valves 33 and 34, respectively. The front end of the water vapor supply path 6 is branched according to the number of mold heating hollow paths 5 provided in the mold 1, and this branched end portion is the inlet 22 of the mold heating hollow path 5 of the mold 1. Is connected to the mold heating cavity 5. One end of the water vapor return path 36 is connected to the outlet 23 of the mold heating cavity 5, and the other end of the water vapor return path 36 is connected to the water introduction path 27 in a branched state. An opening / closing valve 35 is provided in the water vapor return path 36.

  Although it does not specifically limit as the coated sand 2 in this invention, The thing which coat | covered the surface of the fireproof aggregate with the binder by mixing a binder with a fireproof aggregate can be used.

  The refractory aggregate is not particularly limited, and can be exemplified by dredged sand, mountain sand, alumina sand, olivine sand, chromite sand, zircon sand, mullite sand, and other artificial sand, These may be used alone or in combination of two or more.

  Further, as the binder, a thermosetting resin is generally used, but saccharides can also be used. You may make it use a thermosetting resin and saccharides together as a binder.

  Examples of the thermosetting resin used for the binder include phenol resins such as resol type, novolac type, and benzylic ether type, furan resin, isocyanate compound, amine polyol resin, polyether polyol resin, and the like. These can be combined with isocyanate compounds, organic esters, hexamethylenetetramine, etc. as curing agents, and tertiary amines, pyridine derivatives, organic sulfonic acids, etc. as curing catalysts, and can be used with thermosetting properties. It is. Among these, a phenol resin is preferable.

  In addition, as the saccharide used in the binder, monosaccharides, oligosaccharides, and polysaccharides can be used, and one type selected from various monosaccharides, oligosaccharides, and polysaccharides can be used alone. You can also select seeds and use them together.

  Although it does not specifically limit as monosaccharide, Glucose (glucose), fructose (fructose), galactose, etc. can be mentioned.

  Examples of oligosaccharides include disaccharides such as maltose (malt sugar), sucrose (sucrose), lactose (lactose), and cellobiose.

  Furthermore, as polysaccharides, there are starch sugar, dextrin, xanthan gum, curdlan, pullulan, cycloamylose, chitin, cellulose, starch, etc., and one of these can be selected or used in combination of two or more. it can. Examples of starch include raw starch and processed starch. Specifically, raw starch such as potato starch, corn starch, high amylose, sweet potato starch, tapioca starch, sago starch, rice starch, amaranth starch, and these modified starches (roasted dextrin, enzyme-modified dextrin, acid-treated starch, Oxidized starch, dialdehyde starch, etherified starch (carboxymethyl starch, hydroxyalkyl starch, cationic starch, methylolated starch, etc.), esterified starch (acetic acid starch, phosphate starch, succinate starch, octenyl succinic acid starch, maleic acid Starch, higher fatty acid esterified starch, etc.), cross-linked starch, kraft starch, wet heat-treated starch, etc. Among these, roasted dextrin, enzyme modified Dextrin, acid treatment starches, those low molecular weight as oxidized starch, and low viscosity, such as cross-linked starch starches are preferred.

  The binder may contain a carboxylic acid as a curing agent for saccharides, particularly polysaccharides. The carboxylic acid is not particularly limited, and examples thereof include oxalic acid, maleic acid, succinic acid, citric acid, butanetetradicarboxylic acid, methyl vinyl ether-maleic anhydride copolymer, and the like. The content of the carboxylic acid in the binder is preferably such that the amount of the carboxylic acid to the saccharide is 0.1 to 10 parts by mass of the carboxylic acid with respect to 100 parts by mass of the saccharide. Carboxylic acid is preferably mixed with saccharide in a state of being dissolved in water in advance because the effect as a curing agent is exhibited highly.

  And, by coating the refractory aggregate particles with a binder or the like and mixing them, the surface of the refractory aggregate can be coated with a coating layer containing the binder to obtain the coated sand 2. is there. The amount of the binder to be coated on the refractory aggregate differs depending on the components and applications and cannot be specified unconditionally. Is generally preferred. Examples of a method for coating the surface of the refractory aggregate with a binder include a hot coat method, a cold coat method, a semi-hot coat method, and a powder solvent method. In any method, the coated sand 2 that is granular and free-flowing can be obtained by coating the surface of the refractory aggregate with a coating layer made of a solid binder at ordinary temperature (30 ° C.).

  FIG. 3 shows a storage tank 14 for storing the coated sand 2, and a nozzle port 17 provided with a cock 39 is provided at the lower end of the storage tank 14. The storage tank 14 is provided with a sand preheater 40 for preheating the coated sand 2 stored in the storage tank 14. In the embodiment of FIG. 3, the sand preheater 40 is formed by a preheating pipe 40 a made of a heat exchange pipe bent in a spiral, and the preheating pipe 40 a is inserted into the central portion of the storage tank 14 and arranged. is there.

  As described above with reference to FIG. 1, the steam main supply path 4 and the steam supply path 6 are branched and connected to the steam delivery path 30 of the steam generator 3. The path 41 is branched. The preheating water vapor supply path 41 is connected to a preheating heat exchanger 42. 52 is an on-off valve provided in the preheating steam supply passage 41. In the preheating heat exchanger 42, an introduction chamber 43 is formed at one end thereof, and a lead-out chamber 44 is formed at the other end, and the heat exchange chamber 45 is formed between the introduction chamber 43 and the lead-out chamber 44. It has become. A large number of heat exchange pipes 51 communicating with the introduction chamber 43 and the outlet chamber 44 are provided in the heat exchange chamber 45. The preheating water vapor supply path 41 is connected to the introduction chamber 43 in the preheating heat exchanger 42. One end of a steam return path 46 is connected to the lead-out chamber 44, and the other end of the steam return path 46 is connected in a branched state to the water introduction path 27 of the boiler 25, similarly to the steam return path 36 of FIG. It is. An air introduction path 47 is connected to one end of the heat exchange chamber 45 of the preheating heat exchanger 42, and a heated air supply path 48 is connected to the other end of the heat exchange chamber 45. In the embodiment of FIG. 3, a blower 49 such as a fan is provided in the air introduction path 47, and air is sent into the heat exchange chamber 45 by the blower 49. The other end of the heated air supply path 48 whose one end is connected to the heat exchange chamber 45 is connected to an inlet 50 at one end of a preheating pipe 40 a constituting the sand preheater 40.

  The apparatus shown in FIGS. 1 and 3 shares one water vapor generator 3. Water is supplied from the water introduction path 27 to the boiler 25 of the water vapor generating device 3, and water vapor is generated by the boiler 25. When the superheater 8 is provided in the steam generator 3, this steam can be further heated to generate superheated steam. The steam generated in this way is sent out from the steam delivery path 30 by opening the on-off valve 32.

  Here, in FIG. 1, the on-off valve 33 of the steam main supply path 4 is closed except when steam is supplied into the cavity 10 of the mold 1 and blown, but the on-off valve 34 of the steam supply path 6 is basically the same. The water vapor is always open, and the water vapor delivered from the water vapor delivery passage 30 is always supplied through the water vapor supply passage 6. The water vapor that has passed through the water vapor supply path 6 in this manner is supplied from the inlet 22 into the mold heating cavity 5 of the mold 1, and after passing through the mold heating cavity 5, the water vapor return path from the outlet 23. Go out to 36. Thus, when passing water vapor through the mold heating cavity 5 in the mold 1, the heating mold 1 can be heated by the water vapor, and the temperature of the mold 1 can be prevented from being lowered. It can be done. The water vapor that has passed through the mold heating cavity 5 goes out to the water vapor return path 36, but since the heat is deprived in order to heat the mold 1, the temperature is lowered. Returned and regenerated to steam again. When the steam supplied from the steam supply path 6 into the mold heating cavity 5 is returned to the boiler 25 through the steam return path 36, the on-off valve 35 provided in the steam return path 36 is opened. Further, a part of the water vapor supplied from the water vapor supply path 6 to the mold heating cavity path 5 is transferred to the cavity 10 through the steam introduction path 7, and the inside of the cavity 10 can also be preheated.

  On the other hand, in FIG. 3, the on-off valve 52 is basically configured so that steam is always supplied from the steam delivery path 30 to the preheating steam supply path 41 branched and connected to the steam delivery path 30 of the steam generator 3. Always open. The steam that has passed through the preheating steam supply passage 41 enters the introduction chamber 43 of the preheating heat exchanger 42, passes through the heat exchange pipe 51, then moves to the outlet 44, and is then discharged to the steam return passage 46. . In addition, air is sent into the heat exchange chamber 45 by the blower 49, and when this air passes through the heat exchange chamber 45, heat exchange is performed with water vapor passing through the heat exchange pipe 51, and in the heat exchange chamber 45. Air is heated. The heated air is sent out from the heat exchange chamber 45 to the heated air supply path 48, and the heated air that has passed through the heated air supply path 48 is supplied from the inlet 50 at one end to the preheating pipe 40a constituting the sand preheater 40. The The coated sand 2 is always stored in the storage tank 14, and the preheating pipe 40a disposed in the central portion of the storage tank 14 is in a state of being buried in the coated sand 2, so that the heated air is supplied to the preheating pipe. When passing through 40a, the coated sand 2 can be heated to preheat the coated sand 2. The heated air that has passed through the preheating pipe 40a is discharged into the atmosphere from the outlet 53 at the end. Further, since the temperature of the steam that has passed through the preheating heat exchanger 42 and is discharged to the steam return path 46 is lowered, it is returned from the water introduction path 27 to the boiler 25 and regenerated again as steam. Here, a large number of small holes may be provided in the preheating pipe 40a along the longitudinal direction thereof, and the heated air passing through the preheating pipe 40a may be blown out from the small holes. The air can be directly applied to the coated sand 2 to preheat the coated sand 2 more efficiently.

  Next, a method for producing a mold using the above apparatus will be described. First, the nozzle port 17 of the storage tank 14 is connected to the injection port 11 of the mold 1. Then, the cock 39 of the nozzle port 17 is opened, the coated sand 2 stored in the storage tank 14 is supplied to the mold 1, and the cavity 10 is filled with the coated sand 2. Since the exhaust port 13 of the mold 1 is closed by the net 12, the coated sand 2 does not leak from the exhaust port 13. After the coated sand 2 is filled into the cavity 10 of the mold 1, the cock 39 of the storage tank 14 is closed, the connection of the storage tank 14 is disconnected from the inlet 11 of the mold 1, and the coated sand 2 is filled into the mold 1. The process ends.

  Next, the water vapor main supply path 4 is connected to the inlet 11 of the mold 1. A connection nozzle 54 is provided at the tip of the water vapor main supply path 4, and the water vapor main supply path 4 is connected to the injection port 11 by inserting the connection nozzle 54 into the injection port 11. . When the on-off valve 33 is opened, the water vapor sent out from the water vapor delivery path 30 of the water vapor generating device 3 is blown into the cavity 10 of the mold 1 through the water vapor main supply path 4. When water vapor is blown into the mold 1, the water contacts the surface of the coated sand 2, so that the coated sand 2 can be directly heated by the high latent heat of the water vapor, and the temperature of the coated sand 2 is around 100 ° C. Rising rapidly. Moreover, the water vapor passes between the particles of the coated sand 2 and penetrates the entire inside of the mold 1 so that the coated sand 2 in the mold 1 can be heated to a uniform temperature. The water vapor blown from the injection port 11 into the mold 1 is exhausted from the exhaust port 13 after heating the coated sand 2 in the mold 1.

  In this way, the coated sand 2 is rapidly heated by the latent heat of the steam blown into the mold 1 so that the binder of the coated sand 2 can be solidified or cured in a short time, thereby shortening the molding time of the mold. Is something that can be done. In this way, after the process of solidifying or curing the binder of the coated sand 2 in the mold 1 and molding the mold is completed, the on-off valve 33 is closed and the steam main supply passage 4 from the inlet 11 of the mold 1 is closed. The connection nozzle 54 is removed, the storage tank 14 is connected to the injection port 11 again as described above, and the process returns to the step of filling the mold 1 with the coated sand 2.

  At this time, as described above, the mold 1 is heated so that the temperature does not decrease by supplying water vapor from the water vapor supply path 6 to the mold heating cavity 5. Accordingly, in heating the coated sand 2 by blowing water vapor into the mold 1 in the mold making process, it is prevented that a part of the heat of the water vapor is taken away by the mold 1, and the water vapor is generated in the mold 1. Condensation can be suppressed, the heating efficiency of the coated sand 2 by water vapor can be kept high, and the molding time of the mold can be further shortened.

  Then, the steam main supply path 4 is connected to the inlet 11 of the mold 1 as described above, and at the same time when the steam is blown into the cavity 10 of the mold 1, the opening / closing valve 35 of the steam return path 36 is Closed. When the on-off valve 35 is closed in this way, the steam supplied from the steam supply path 6 to the mold heating cavity 5 is not discharged from the outlet 23 to the steam return path 36, so It is introduced into the cavity 10 through the introduction path 7 and blown into the cavity 10 from the outer peripheral surface of the cavity 10. Here, it is difficult to uniformly distribute the water vapor supplied from the inlet 11 into the cavity 10 to every corner of the cavity 10, especially when the shape of the mold is complicated or elongated. Although difficult, in this way, water vapor is blown into the entire cavity 10 by blowing water vapor from the outer periphery into the cavity 10 from the mold heating cavity 5 formed so as to surround the cavity 10 and through the vapor introduction passage 7. In this case, water vapor can be applied to the entire coated sand 2 filled in the cavity 10, and the entire coated sand 2 can be heated uniformly. Therefore, even a mold having a complicated shape and an elongated shape can be easily manufactured uniformly. As described above, after the process of forming the mold by heating the coated sand 2 in the cavity 10 with water vapor, the open / close valve 35 of the main steam supply path 4 is closed and the open / close valve 35 is opened. The steam in the mold heating cavity 5 is returned from the steam return path 36 to the boiler 25.

  Here, the mold 1 is formed of a dense metal material that does not allow gas to pass through. However, as described in International Publication WO2007 / 132669, which cited the mold 1 as Patent Document 3, You may make it form with a porous material. When the mold 1 is formed of a porous material in this way, the water vapor in the mold heating cavity 5 can be blown into the cavity 10 not only through the steam introduction channel 7 but also through the porous communication hole. It will be possible. However, when the mold 1 is formed of a porous material, the inner peripheral surface of the cavity 10 becomes porous, so that the mold is solidified or cured in a state where the binder of the coated sand is contained in the hole, and the mold is molded. May stick to the inner peripheral surface of the cavity 10 and it may become very difficult to release.

  Further, as described above, the coated sand 2 supplied from the storage tank 14 to the mold 1 is preheated by the sand preheater 40. Therefore, at the initial stage of blowing water vapor into the cavity 10 of the mold 1, it is possible to prevent the latent heat of the water vapor from being taken away by the coated sand 2 and to suppress the water vapor from condensing in the mold 1. The heating efficiency of the coated sand 2 by steam can be maintained high, and the molding time of the mold can be shortened.

  Then, the steam is blown into the cavity 10 of the mold 1 from the inlet 11 only in the process of heating the coated sand 2 in the mold 1 to mold the mold. As described above, the steam generator 3 The mold 1 is heated or the coated sand 2 in the storage tank 14 is heated using the water vapor generated in step 1. The heating of the mold 1 and the coated sand 2 are performed as follows. It is always performed not only in the mold making process but also in the process of filling the mold 1 with the coated sand 2. Therefore, even if the water vapor is always generated by the water vapor generating device 3, the water vapor can be effectively used outside the process of molding the mold, and the water vapor is wasted in other than the mold molding process. It disappears and water vapor can always be used effectively.

  In the embodiment of FIG. 1 described above, the coated sand 2 is supplied from the inlet 11 of the mold 1 and filled into the cavity 10, and then the main steam supply passage 4 is connected to the inlet 11 to supply the main steam. Although the steam is blown into the cavity 10 through the path 4, the coated sand 2 in the cavity 10 is heated mainly by the steam supplied from the steam main supply path 4, but the steam main supply path 4 is not provided. It can also be formed into a system. FIG. 4 shows an example thereof. The steam supply path 6 of the steam generator 3 is connected to the steam supply path 6 and the preheating steam supply path 41, and the steam main supply path 4 is not provided.

  In the system of the embodiment of FIG. 4 as well, the on-off valve 34 of the water vapor supply path 6 is basically always open, and the water vapor sent from the water vapor supply path 30 is used for heating the mold 1 through the water vapor supply path 6. It is always supplied into the cavity 5. The on-off valve 35 of the water vapor return path 36 is also open, and the water vapor supplied from the water vapor supply path 6 to the mold heating cavity path 5 passes through the mold heating cavity path 5 and then exits to the water vapor return path 36. The mold 1 is preheated when the water vapor passes through the mold heating cavity 5 in this way. Then, as described above, the nozzle port 17 of the storage tank 14 is connected to the injection port 11 of the mold 1, and the coated sand 2 is supplied and filled into the cavity 10, and then the lid 11 is put on the injection port 11. Close up. The lid 57 is preferably a breathable lid 57 stretched with a net 58 or the like.

  Next, when the on-off valve 35 of the steam return path 36 is closed, the steam supplied from the steam delivery path 30 through the steam supply path 6 into the mold heating cavity 5 cannot go out to the steam return path 36. Therefore, the water vapor in the mold heating cavity 5 is blown into the cavity 10 through the steam introduction path 7. Accordingly, the mold can be formed by heating the coated sand 2 in the cavity 10 by using the steam supplied to the mold heating cavity 5 in order to preheat the mold 1. is there. At this time, by forming the lid 57 that closes the injection port 11 so as to be air permeable, the water vapor blown into the cavity 10 from the mold heating cavity 5 through the steam introduction channel 7 is discharged from the exhaust port 13 of the mold 1. In addition, the air is exhausted from the inlet 11 through the lid 57, and the water vapor can be distributed more uniformly in the cavity 10. After the molding of the mold is completed, the steam in the mold heating cavity 5 is sent to the steam return path 36 by opening the on-off valve 35 of the steam return path 36.

  In the embodiment shown in FIG. 4, after the nozzle port 17 of the storage tank 14 is connected to the injection port 11 and the coated sand 2 is supplied to the cavity 10 of the mold 1, the storage tank 14 is removed from the injection port 11. Thereafter, the on-off valve 35 of the water vapor return path 36 is closed so that water vapor is blown into the cavity 10 from the mold heating cavity path 5 through the steam introduction path 7, but the nozzle port 17 of the storage tank 14 is connected to the injection port 11. The open / close valve 35 of the steam return path 36 is closed while the cock 39 of the nozzle port 17 is closed without disconnecting it, so that the cavity 10 passes from the mold heating cavity path 5 through the steam introduction path 7. Water vapor may be blown into the tank.

DESCRIPTION OF SYMBOLS 1 Mold 2 Coated sand 3 Steam generator 4 Steam main supply path 5 Cavity path for heating 6 Steam supply path 7 Steam introduction path 8 Superheater 14 Storage tank
22 entrance
23 Exit
33 On-off valve
35 On-off valve
36 Steam return path 40 Sand preheater

Claims (8)

Manufacture of a mold comprising a mold having a cavity filled with a coated sand coated with a refractory aggregate with a binder, and a steam generator for generating water vapor for heating the coated sand filled in the mold In the apparatus, the mold heating cavity provided in the mold at a position surrounding the cavity, and the water vapor sent from the steam generator provided between the steam generator and the mold heating cavity is used as the mold heating cavity. A plurality of steam supply paths that are constantly supplied to the mold, and a steam introduction path that is provided between the mold heating cavity path and the cavity and that introduces the steam supplied to the mold heating cavity path into the cavity. the use hollow path inlet and outlet are formed, the steam supply passage to the inlet, with the water vapor return passage is connected to the outlet, the coated sand into the cavity of the filling Mold manufacturing apparatus that is closed off valve, characterized in that provided in the steam return path after.   2. The mold manufacturing apparatus according to claim 1, further comprising a steam main supply path that is provided between the steam generator and the cavity and supplies the steam delivered from the steam generator into the cavity. 3. The mold manufacturing apparatus according to claim 2, wherein the on-off valve of the water vapor return path is closed simultaneously with the supply of water vapor from the main water supply path to the cavity and is opened simultaneously with the stop of the supply. 4. The mold according to claim 2 or 3, wherein the steam main supply passage is provided with an on-off valve that opens after the cavity of the mold is filled with the coated sand and supplies steam into the cavity. manufacturing device. 5. The water vapor delivery path for delivering the water vapor generated by the water vapor generation device is provided, and the water vapor supply path and the water vapor main supply path are branched and connected to the water vapor delivery path. The mold manufacturing apparatus described in 1. The mold manufacturing apparatus according to any one of claims 2 to 5, wherein the steam return path returns the steam that has passed through the mold heating cavity path to a steam generator. The said steam generator is provided with a superheater, The said steam is superheated steam produced | generated by overheating with a superheater, The manufacturing apparatus of the casting mold in any one of the Claims 1 thru | or 6 characterized by the above-mentioned. A storage tank for supplying the coated sand to the cavity of the mold is provided, and the storage tank is provided with a sand preheater for preheating the coated sand using the steam generated by the steam generator as a heat source. The mold manufacturing apparatus according to any one of 1 to 7 .

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